86 results on '"Morrison KA"'
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2. Dharmic projects, imperial reservoirs, and new temples of India: An historical perspective on dams in India
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Morrison Kathleen
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dams ,development ,South Asia ,irrigation ,siltation ,temples ,reservoirs ,religion ,Ecology ,QH540-549.5 - Abstract
As international attention continues to focus on large dam projects across Asia, it is worth noting that conflicts over the politics of and environmental changes caused by dams in India are not new. Population dislocation, siltation, disease, floods caused by catastrophic dam failure, raised water tables, high costs and low returns-all of these concerns, and others, can be discussed in the context of reservoir projects ten, one hundred, or even one thousand years old. In this paper, I identify some of the major issues in the political ecology of contemporary dam projects and show how these same issues have played out in southern India over the last thousand years, suggesting that historical attention to the cultural and political context of reservoir construction might help us to understand some aspects of contemporary conflicts.
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- 2010
3. The implications of ‘jam’ and other ideation technologies for organisational decision making
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Morrison Kate
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Anthropology ,GN1-890 ,Communication. Mass media ,P87-96 - Abstract
New advances in collaborative technologies, often grouped under the umbrella term ‘web 2.0’, are changing the opportunity space for organisational collaboration and decision making. Research and development can now be outsourced to external self-organising communities of scientists, new business models rely wholly on content created by end users and customers are increasingly asked for input to the development of new products and services. The way in which many strategic and operational decisions are made, once the sole prevail of executive management, is being challenged by new forms of knowledge, expertise and opinion from non-management employees, and increasingly, from those outside the organisation such as customers, partners and suppliers. The widespread adoption of web 2.0 technologies and their increasing use in the business context, in other words, is creating an inevitable tension between traditional ‘top-down’ strategic decision-making principles and ‘bottom-up’, ad hoc and sometimes unstructured collaborative processes.
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- 2009
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4. Strengthening integrated research and capacity development within the Caribbean region
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Dewailly Eric, Morrison Karen, Forde Martin, Badrie Neela, and Robertson Lyndon
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Public aspects of medicine ,RA1-1270 - Abstract
Abstract Background The Caribbean region, like other developing regions of the world, faces significant challenges in conducting research, especially in the context of limited resource capacities and capabilities. Further, due to its diverse and multiple island states, research capacity is scattered and unevenly spread within the region. The Caribbean EcoHealth Programme (CEHP) is a research program that is structured to improve the capacity and capability of health professionals in the Caribbean region to respond in integrative and innovative ways to on-going and emerging environmental health challenges by means of multi-sectoral interventions. Methods Core parts of the CEHP’s mission are to (1) conduct collaborative research in areas that the region has identified as critical; (2) build and strengthening integrated approaches to research; and (3) develop and enhance basic research capacity within the Caribbean region. Fundamental to the success of the CEHP’s human and resource development mission has been its use of the Atlantis Mobile Laboratory (AML). The AML has allowed the CEHP program to move throughout the Caribbean and be able to respond to calls for specific research and capacity building opportunities. Results The CEHP’s five main research projects have generated the following results: (1) the Persistent Organic Pollutants (POPs) study has evaluated human exposures to POPs, heavy metals, pesticides, and zoonotic infections; (2) the Burden of Illness (BOI) studies have developed protocols for the testing of foodborne microorganisms, strengthen laboratory analytical capabilities, and determined the prevalence and incidence of food-borne illness; (3) the Rainwater Harvesting (RWH) study has evaluated the microbial and chemical quality of rainwater harvesting systems; (4) the Ecotoxicology Water (ETW) studies have provided much needed data on the quality of recreational and drinking water supplies, and (5) the Food Safety Training Program has developed Diploma and M.Sc Agri-Food Safety and Quality Assurance programmes. Conclusions The CEHP program provides a successful example of how a collaborative instead of researcher driven research agenda can lead to not only the generation of needed information, but also leave within the region where the research has been carried out the capacity and capabilities to continue to do so independent of outside interventions.
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- 2011
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5. CCi Mainstreaming and RHD Jams Outcomes Report
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Morrison Kate
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Anthropology ,GN1-890 ,Communication. Mass media ,P87-96 - Abstract
The ARC Centre of Excellence in Creative Industries and Innovation (CCi) commissioned two jams –online collaborative events – to discover new ideas for improving outcomes in two important aspects of the Centre’s work.
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- 2009
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6. Social network analysis of non-economic rules
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Morrison Kate
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Anthropology ,GN1-890 ,Communication. Mass media ,P87-96 - Published
- 2008
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7. Rationale and design of South Asian Birth Cohort (START): a Canada-India collaborative study
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Anand Sonia S, Vasudevan Anil, Gupta Milan, Morrison Katherine, Kurpad Anura, Teo Koon K, and Srinivasan Krishnamachari
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Birth cohort ,South Asian ,Adiposity ,Insulin resistance ,Early origins ,India ,Canada ,Public aspects of medicine ,RA1-1270 - Abstract
Abstract Background People who originate from the Indian subcontinent (South Asians) suffer among the highest rates of type 2 diabetes in the world. Prior evidence suggests that metabolic risk factors develop early in life and are influenced by maternal and paternal behaviors, the intrauterine environment, and genetic factors. The South Asian Birth Cohort Study (START) will investigate the environmental and genetic basis of adiposity among 750 South Asian offspring recruited from highly divergent environments, namely, rural and urban India and urban Canada. Methods Detailed information on health behaviors including diet and physical activity, and blood samples for metabolic parameters and DNA are collected from pregnant women of South Asian ancestry who are free of significant chronic disease. They also undergo a provocative test to diagnose impaired glucose tolerance and gestational diabetes. At delivery, cord blood and newborn anthropometric indices (i.e. birth weight, length, head circumference and skin fold thickness) are collected. The mother and growing offspring are followed prospectively and information on the growth trajectory, adiposity and health behaviors will be collected annually up to age 3 years. Our aim is to recruit a minimum of 750 mother-infant pairs equally divided between three divergent environments: rural India, urban India, and Canada. Summary The START cohort will increase our understanding of the environmental and genetic determinants of adiposity and related metabolic abnormalities among South Asians living in India and Canada.
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- 2013
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8. Should I stay or should I go? Understanding families’ decisions regarding initiating, continuing, and terminating health services for managing pediatric obesity: the protocol for a multi-center, qualitative study
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Ball Geoff DC, Garcia Arnaldo Perez, Chanoine Jean-Pierre, Morrison Katherine M, Legault Laurent, Sharma Arya M, Gokiert Rebecca, and Holt Nicholas L
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Obesity ,Pediatric ,Treatment ,Family ,Qualitative ,Attrition ,Health services ,Public aspects of medicine ,RA1-1270 - Abstract
Abstract Background At least two million Canadian children meet established criteria for weight management. Due to the adverse health consequences of obesity, most pediatric weight management research has examined the efficacy and effectiveness of interventions to improve lifestyle behaviors, reduce co-morbidities, and enable weight management. However, little information is available on families’ decisions to initiate, continue, and terminate weight management care. This is an important knowledge gap since a substantial number of families fail to initiate care after being referred for weight management while many families who initiate care discontinue it after a brief period of time. This research aims to understand the interplay between individual, family, environmental, and systemic factors that influence families’ decisions regarding the management of pediatric obesity. Methods/Design Individual interviews will be conducted with children and youth with obesity (n = 100) and their parents (n = 100) for a total number of 200 interviews with 100 families. Families will be recruited from four Canadian multi-disciplinary pediatric weight management centers in Vancouver, Edmonton, Hamilton, and Montreal. Participants will be purposefully-sampled into the following groups: (i) Non-Initiators (5 families/site): referred for weight management within the past 6 months and did not follow-up the referral; (ii) Initiators (10 families/site): referred for weight management within the past 6 months and did follow-up the referral with at least one clinic appointment; and (iii) Continuers (10 families/site): participated in a formal weight management intervention within the past 12 months and did continue with follow-up care for at least 6 months. Interviews will be digitally recorded and analyzed using an ecological framework, which will enable a multi-level evaluation of proximal and distal factors that underlie families’ decisions regarding initiation, continuation, and termination of care. Demographic and anthropometric/clinical data will also be collected. Discussion A better understanding of family involvement in pediatric weight management care will help to improve existing health services in this area. Study data will be used in future research to develop a validated survey that clinicians working in pediatric obesity management can use to understand and enhance their own health services delivery.
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- 2012
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9. Protocol for diaphragm pacing in patients with respiratory muscle weakness due to motor neurone disease (DiPALS): a randomised controlled trial
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McDermott Christopher J, Maguire Chin, Cooper Cindy L, Ackroyd Roger, Baird Wendy O, Baudouin Simon, Bentley Andrew, Bianchi Stephen, Bourke Stephen, Bradburn Mike J, Dixon Simon, Ealing John, Galloway Simon, Karat Dayalan, Maynard Nick, Morrison Karen, Mustfa Naveed, Stradling John, Talbot Kevin, Williams Tim, and Shaw Pamela J
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Neurology. Diseases of the nervous system ,RC346-429 - Abstract
Abstract Background Motor neurone disease (MND) is a devastating illness which leads to muscle weakness and death, usually within 2-3 years of symptom onset. Respiratory insufficiency is a common cause of morbidity, particularly in later stages of MND and respiratory complications are the leading cause of mortality in MND patients. Non Invasive Ventilation (NIV) is the current standard therapy to manage respiratory insufficiency. Some MND patients however do not tolerate NIV due to a number of issues including mask interface problems and claustrophobia. In those that do tolerate NIV, eventually respiratory muscle weakness will progress to a point at which intermittent/overnight NIV is ineffective. The NeuRx RA/4 Diaphragm Pacing System was originally developed for patients with respiratory insufficiency and diaphragm paralysis secondary to stable high spinal cord injuries. The DiPALS study will assess the effect of diaphragm pacing (DP) when used to treat patients with MND and respiratory insufficiency. Method/Design 108 patients will be recruited to the study at 5 sites in the UK. Patients will be randomised to either receive NIV (current standard care) or receive DP in addition to NIV. Study participants will be required to complete outcome measures at 5 follow up time points (2, 3, 6, 9 and 12 months) plus an additional surgery and 1 week post operative visit for those in the DP group. 12 patients (and their carers) from the DP group will also be asked to complete 2 qualitative interviews. Discussion The primary objective of this trial will be to evaluate the effect of Diaphragm Pacing (DP) on survival over the study duration in patients with MND with respiratory muscle weakness. The project is funded by the National Institute for Health Research, Health Technology Assessment (HTA) Programme (project number 09/55/33) and the Motor Neurone Disease Association and the Henry Smith Charity. Trial Registration: Current controlled trials ISRCTN53817913. The views and opinions expressed therein are those of the authors and do not necessarily reflect those of the HTA programme, NIHR, NHS or the Department of Health.
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- 2012
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10. One Health and EcoHealth in Ontario: a qualitative study exploring how holistic and integrative approaches are shaping public health practice in Ontario
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Leung Zee, Middleton Dean, and Morrison Karen
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Public health practice ,One Health ,EcoHealth ,Governance ,Sustainability ,Cross-sectoral partnerships ,Public aspects of medicine ,RA1-1270 - Abstract
Abstract Background There is a growing recognition that many public health issues are complex and can be best understood by examining the relationship between human health and the health of the ecosystems in which people live. Two approaches, One Health and Ecosystem Approaches to Health (EcoHealth), can help us to better understand these intricate and complex connections, and appear to hold great promise for tackling many modern public health dilemmas. Although both One Health and EcoHealth have garnered recognition from numerous health bodies in Canada and abroad, there is still a need to better understand how these approaches are shaping the practice of public health in Ontario. The purpose of this study was to characterize how public health actors in Ontario are influenced by the holistic principles which underlie One Health and EcoHealth, and to identify important lessons from their experiences. Methods Ten semi-structured interviews were conducted with ten participants from the public health sphere in Ontario. Participants encompassed diverse perspectives including infectious disease, food systems, urban agriculture, and environmental health. Interviews were recorded, transcribed and analyzed using qualitative content analysis to identify major themes and patterns. Results Four major themes emerged from the interviews: the importance of connecting human health with the environment; the role of governance in promoting these ideas; the value of partnerships and collaborations in public health practice; and the challenge of operationalizing holistic approaches to public health. Overall study participants were found to be heavily influenced by concepts couched in EcoHealth and One Health literature, despite a lack of familiarity with these fields. Conclusions Although One Health and EcoHealth are lesser known approaches in the public health sphere, their holistic and systems-based principles were found to influence the thoughts, values and experiences of public health actors interviewed in this study. This study also highlights the critical role of governance and partnerships in facilitating a holistic approach to health. Further research on governance and partnership models, as well as systems-based organizational working practices, is needed to close the gap between One Health and EcoHealth theory and public health practice.
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- 2012
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11. Protocol for a double-blind randomised placebo-controlled trial of lithium carbonate in patients with amyotrophic Lateral Sclerosis (LiCALS) [Eudract number: 2008-006891-31]
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Kelly Joanna, Thornhill Marie, Murphy Caroline, Morrison Karen E, Young Carolyn A, Shaw Pamela J, Al-Chalabi Ammar, Steen I Nicholas, and Leigh P Nigel
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Neurology. Diseases of the nervous system ,RC346-429 - Abstract
Abstract Background Amyotrophic lateral sclerosis is a rapidly progressive neurodegenerative disorder characterised by loss of motor neurons leading to severe weakness and death from respiratory failure within 3-5 years. Riluzole prolongs survival in ALS. A published report has suggested a dramatic effect of lithium carbonate on survival. 44 patients were studied, with 16 randomly selected to take LiCO3 and riluzole and 28 allocated to take riluzole alone. In the group treated with lithium, no patients had died (i.e., 100% survival) at the end of the study (15 months from entry), compared to 71% surviving in the riluzole-only group. Although the trial can be criticised on several grounds, there is a substantial rationale from other laboratory studies that lithium is worth investigating therapeutically in amyotrophic lateral sclerosis. Methods/Design LiCALS is a multi-centre double-blind randomised parallel group controlled trial of the efficacy, safety, and tolerability of lithium carbonate (LiCO3) at doses to achieve stable 'therapeutic' plasma levels (0.4-0.8 mmol/L), plus standard treatment, versus matched placebo plus standard treatment, in patients with amyotrophic lateral sclerosis. The study will be based in the UK, in partnership with the MND Association and DeNDRoN (the Dementias and Neurodegnerative Diseases Clinical Research Network). 220 patients will be recruited. All patients will be on the standard treatment for ALS of riluzole 100 mg daily. The primary outcome measure will be death from any cause at 18 months defined from the date of randomisation. Secondary outcome measures will be changes in three functional rating scales, the ALS Functional Rating Scale-Revised, The EuroQOL (EQ-5D), and the Hospital Anxiety and Depression Scale. Eligible patients will have El Escorial Possible, Laboratory-supported Probable, Probable or Definite amyotrophic lateral sclerosis with disease duration between 6 months and 36 months (inclusive), vital capacity ≥ 60% of predicted within 1 month prior to randomisation and age at least18 years. Discussion Patient recruitment began in June 2009 and the last patient is expected to complete the trial protocol in November 2011. Trial registration Current controlled trials ISRCTN83178718
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- 2011
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12. Methylation of class II transactivator gene promoter IV is not associated with susceptibility to Multiple Sclerosis
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Lincoln Matthew R, DeLuca Gabriele C, Herrera Blanca M, Morrison Katie M, Dyment David A, Ramagopalan Sreeram V, Orton Sarah M, Handunnetthi Lahiru, Chao Michael J, Sadovnick A Dessa, and Ebers George C
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Internal medicine ,RC31-1245 ,Genetics ,QH426-470 - Abstract
Abstract Background Multiple sclerosis (MS) is a complex trait in which alleles at or near the class II loci HLA-DRB1 and HLA-DQB1 contribute significantly to genetic risk. The MHC class II transactivator (MHC2TA) is the master controller of expression of class II genes, and methylation of the promoter of this gene has been previously been shown to alter its function. In this study we sought to assess whether or not methylation of the MHC2TA promoter pIV could contribute to MS disease aetiology. Methods In DNA from peripheral blood mononuclear cells from a sample of 50 monozygotic disease discordant MS twins the MHC2TA promoter IV was sequenced and analysed by methylation specific PCR. Results No methylation or sequence variation of the MHC2TA promoter pIV was found. Conclusion The results of this study cannot support the notion that methylation of the pIV promoter of MHC2TA contributes to MS disease risk, although tissue and timing specific epigenetic modifications cannot be ruled out.
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- 2008
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13. Dietary carbohydrate restriction in type 2 diabetes mellitus and metabolic syndrome: time for a critical appraisal
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Roth Karl S, Ravnskov Uffe, Nielsen Jørgen, Morrison Katharine, McFarlane Samy I, Manninen Anssi H, Lustig Robert H, Larson Gabriel, Jacobs David B, Gleed Amy, Fine Eugene J, Feinman Richard D, Draznin Boris, Dahlqvist Annika, Bernstein Richard K, Accurso Anthony, Silvestre Ricardo, Sowers James R, Sundberg Ralf, Volek Jeff S, Westman Eric C, Wood Richard J, Wortman Jay, and Vernon Mary C
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Nutrition. Foods and food supply ,TX341-641 ,Nutritional diseases. Deficiency diseases ,RC620-627 - Abstract
Abstract Current nutritional approaches to metabolic syndrome and type 2 diabetes generally rely on reductions in dietary fat. The success of such approaches has been limited and therapy more generally relies on pharmacology. The argument is made that a re-evaluation of the role of carbohydrate restriction, the historical and intuitive approach to the problem, may provide an alternative and possibly superior dietary strategy. The rationale is that carbohydrate restriction improves glycemic control and reduces insulin fluctuations which are primary targets. Experiments are summarized showing that carbohydrate-restricted diets are at least as effective for weight loss as low-fat diets and that substitution of fat for carbohydrate is generally beneficial for risk of cardiovascular disease. These beneficial effects of carbohydrate restriction do not require weight loss. Finally, the point is reiterated that carbohydrate restriction improves all of the features of metabolic syndrome.
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- 2008
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14. Enhancement of Low Temperature Superionic Conductivity by Suppression of Li Site Ordering in Li 7 Si 2-x Ge x S 7 I.
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Han G, Daniels LM, Vasylenko A, Morrison KA, Corti L, Collins CM, Niu H, Chen R, Roberston CM, Blanc F, Dyer MS, Claridge JB, and Rosseinsky MJ
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Ge
4+ substitution into the recently discovered superionic conductor Li7 Si2 S7 I is demonstrated by synthesis of Li7 Si2-x Gex S7 I, where x≤1.2. The anion packing and tetrahedral silicon location of Li7 Si2 S7 I are retained upon substitution. Single crystal X-ray diffraction shows that substitution of larger Ge4+ for Si4+ expands the unit cell volume and further increases Li+ site disorder, such that Li7 Si0.88 Ge1.12 S7 I has one Li+ site more (sixteen in total) than Li7 Si2 S7 I. The ionic conductivity of Li7 Si0.8 Ge1.2 S7 I (x=1.2) at 303 K is 1.02(3)×10-2 S cm-1 with low activation energies for Li+ transport demonstrated over a wide temperature range by AC impedance and7 Li NMR spectroscopy. All sixteen Li+ sites remain occupied to temperatures as low as 30 K in Li7 Si0.88 Ge1.12 S7 I as a result of the structural expansion. This differs from Li7 Si2 S7 I, where the partial Li+ site ordering observed below room temperature reduces the ionic conductivity. The suppression of Li+ site depopulation by Ge4+ substitution retains the high mobility to temperatures as low as 200 K, yielding low temperature performance comparable with state-of-the-art Li+ ion conducting materials., (© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)- Published
- 2024
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15. Risk Factors for Acute-Level Hospital Course in Pediatric Craniofacial Fractures.
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Perez-Otero S, Cassidy MF, Morrison KA, Brydges HT, Tran D, Muller J, Flores RL, and Ceradini DJ
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- Humans, Risk Factors, Child, Male, Female, Child, Preschool, Adolescent, Infant, Databases, Factual, Retrospective Studies, United States epidemiology, Facial Bones injuries, Hospitalization statistics & numerical data, Tracheostomy statistics & numerical data, Skull Fractures epidemiology
- Abstract
Purpose: The pediatric craniofacial trauma literature is limited to single institutions or short study periods. Herein, this study analyzes a national database over 10 years to delineate the epidemiology of pediatric craniofacial fractures and to identify risk factors for acute-level hospital course in the largest series to date., Methods: Utilizing the National Trauma Data Bank, pediatric craniofacial fractures admitted between 2010 and 2019 were identified. Descriptive analyses and multivariable regression were performed to identify risk factors for acute-level hospital course., Results: A total of 155,136 pediatric craniofacial fracture cases were reviewed, including cranial vault (49.0%), nasal (22.4%), midface (21.0%), mandibular (20.2%), and orbital floor fractures (13.7%). Midface and orbital floor fractures occurred commonly as multicraniofacial fractures. Cranial vault fractures were the most common among all age groups, but frequency declined with age. In contrast, facial fractures increased with age. Despite the inherent complexity of multicraniofacial trauma, isolated fractures remained a concern for acute-level hospital course.Cranial vault and midface fractures had an increased risk of intracranial injury and intensive care unit admission (P<0.001). Mandibular and midface fractures had an increased risk for cervical spine fracture and tracheostomy (P<0.001). Patient and injury-specific risk factors among the fractures with the strongest association for each outcome-cranial vault and mandible-were identified., Conclusions: The inherent limitations of prior studies-geographical biases, small cohorts, and short-term study periods-were addressed. Describing the independent contribution of each craniofacial fracture to the risk of acute-level hospital course outcomes can be employed to better optimize risk stratification, counseling, and management., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 by Mutaz B. Habal, MD.)
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- 2024
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16. Analyzing Epidemiology and Hospital Course Outcomes of LeFort Fractures in the Largest National Pediatric Trauma Database.
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Perez Otero S, Cassidy MF, Morrison KA, Brydges HT, Muller J, Flores RL, and Ceradini DJ
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Study Design: Retrospective observational study., Objective: This study analyzes the epidemiology of pediatric Le Fort fractures and assesses the incidence of concomitant injuries and acute-level hospital course using the largest, national pediatric trauma database to date., Methods: Pediatric midface and Le Fort fractures from 2016-2019 were identified in the National Trauma Data Bank. Descriptive analyses of Le Fort compared to non-Le Fort midface fractures were performed. Multivariable regression assessed whether Le Fort fractures were risk factors for ICU admission, intracranial injury, cervical spine (C-spine) fracture, tracheostomy, and mortality., Results: A total of 1489 patients with Le Fort fractures were identified. There were 520 Le Fort I, 632 Le Fort II, and 609 Le Fort III fractures. Fracture incidence increased with age. Le Fort fractures showed higher rates of concomitant intracranial injury ( P < 0.001), ICU admission ( P < 0.001), C-spine fracture ( P < 0.001), and tracheostomy ( P < 0.001). Incidence of all the above increased with higher-grade Le Fort fractures. Le Fort III fractures had higher rates of mortality than non-Le Fort midface fractures (7.6% vs 3.2%). Multivariable regression showed that all Le Fort patterns were independent risk factors for tracheostomy and ICU admission, but only Le Fort I for C-spine fractures., Conclusions: The incidence of Le Fort fractures appears to increase with age. Higher category Le Fort fractures are associated with greater morbidity., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2024.)
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- 2024
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17. Association of Timing With Postoperative Complications in the Management of Open Distal Radius Fractures.
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Morrison KA, Rocks MC, Comunale V, Desai K, Nicholas RS, Azad A, Ayalon O, and Hacquebord JH
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Background: This study investigates whether open distal radius fractures (ODRFs) treated after 24 hours from time of injury have an increased risk of infection or overall complication profile compared with those treated within 24 hours., Methods: Retrospective review was performed of all patients treated for ODRF over a 6-year period at a single large academic institution. Postoperative complications included surgical site infections, need for revision irrigation and debridement, delayed soft tissue healing, loss of reduction, nonunion, and malunion., Results: One-hundred twenty patients were treated for ODRF. Mean (SD) age at time of injury was 59.92 (17.68) years. Twenty patients (16.7%) had postoperative complications. Regarding mechanism of injury, 78 (65.0%) had a low-energy and 42 (35.0%) had a high-energy injury. Age and fracture grade were not significant factors. Mean (SD) open wound size was 1.18 (1.57) cm. Mean (SD) time from injury presentation to the emergency department (ED) and first dose of intravenous antibiotics was 3.07 (4.05) hours and mean (SD) time from presentation to the ED and operative treatment was 11.90 (6.59) hours, which did not show a significant association with postoperative complications. Twenty-four patients (20.0%) were treated greater than 24 hours after presentation to the ED, which was not significantly distinct from those treated within 24 hours., Conclusion: Patients with ODRFs treated after 24 hours were not associated with a greater risk of postoperative complications. Factors including age, energy and mechanism of injury, and fracture grade did not alter outcome in any statistically significant manner., Level of Evidence: Level IV., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
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- 2024
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18. Anatomical Study of Domain Rescue of Palatal Length in Patients With a Wide Cleft Palate: Buccal Flap Reconstruction in Primary Palatoplasty.
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Morrison KA, Park J, Rochlin D, Lico M, and Flores RL
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- Humans, Infant, Surgical Flaps, Palate, Soft surgery, Retrospective Studies, Treatment Outcome, Cleft Palate surgery, Cleft Palate complications, Plastic Surgery Procedures, Fistula surgery
- Abstract
Background: This study characterizes the potential loss of velar length in patients with a wide cleft and rescue of this loss of domain by local flap reconstruction, providing anatomic evidence in support of primary lengthening of the soft palate during palatoplasty., Methods: A retrospective review was conducted of all patients with a cleft palate at least 10mm in width, who underwent primary palatoplasty with a buccal flap prior to 18 months of age over a 2-year period. All patients underwent primary palatoplasty with horizontal transection of the nasal mucosa, which was performed after nasal mucosa repair, but prior to muscular reconstruction. The resulting palatal lengthening was measured and the mucosal defect was reconstructed with a buccal flap., Results: Of the 22 patients included, 3 (13.6%) had a history of Pierre Robin sequence, and 5 (22.7%) had an associated syndrome. No patients had a Veau I cleft, 7 (31.8%) had a Veau II, 12 (54.5%) had a Veau III, and 3 had (13.6%) a Veau IV cleft. All patients had a right buccal flap during primary palatoplasty. The mean cleft width at the posterior nasal spine was 10.6 ± 2.82mm, and mean lengthening of the velum after horizontal transection of the nasal mucosa closure was 10.5 ± 2.23mm. There were 2 (9.1%) fistulas, 1 (4.5%) wound dehiscence, 1 (4.5%) 30-day readmission, and no bleeding complications., Conclusions: Patients with a wide cleft palate have a potential loss of 1cm velar length. The buccal flap can rescue the loss of domain in palatal length, and potentially improve palatal excursion., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
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- 2024
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19. The effect of polymer end-group on the formation of styrene - maleic acid lipid particles (SMALPs).
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Neville GM, Morrison KA, Shilliday ER, Doutch J, Dalgliesh R, Price GJ, and Edler KJ
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A series of block copolymers comprising styrene and maleic acid (SMA) has been prepared using RAFT polymerisation. RAFT often results in a large hydrophobic alkylthiocarbonylthio end group and this work examines its effect on the solution behaviour of the copolymers. SMA variants with, and without, this end group were synthesised and their behaviour compared with a commercially-available random copolymer of similar molecular weight. Dynamic light scattering and surface tension measurements found the RAFT-copolymers preferentially self-assembled into higher-order aggregates in aqueous solution. Small angle neutron scattering using deuterated styrene varients add support to the accepted model that these agreggates comprise a solvent-protected styrenic core with an acid-rich shell. Replacing the hydrophobic RAFT end group with a more hydrophilic nitrile caused differences in the resulting surface activity, attributed to the ability of the adjoining styrene homoblock to drive aggregation. Each of the copolymers formed SMALP nanodiscs with DMPC lipids, which were found to encapsulate a model membrane protein, gramicidin. However, end group variation affected solubilisition of DPPC, a lipid with a higher phase transition temperature. When using RAFT-copolymers terminated with a hydrophobic group, swelling of the bilayer and greater penetration of the homoblock into the nanodisc core occurred with increasing homoblock length. Conversely, commercial and nitrile-terminated RAFT-copolymers produced nanodisc sizes that stayed constant, instead indicating interaction at the edge of the lipid patch. The results highlight how even minor changes to the copolymer can modify the amphiphilic balance between regions, knowledge useful towards optimising copolymer structure to enhance and control nanodisc formation.
- Published
- 2023
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20. The Underused Superomedial Pedicle Reduction Mammaplasty: Safe and Effective Outcomes.
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Morrison KA, Karp NS, and Choi M
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- Female, Humans, Young Adult, Adult, Middle Aged, Nipples surgery, Hypertrophy surgery, Hypertrophy etiology, Retrospective Studies, Cicatrix etiology, Treatment Outcome, Surgical Flaps surgery, Mammaplasty adverse effects, Mammaplasty methods
- Abstract
Background: The superomedial pedicle for reduction mammaplasty remains less commonly performed than the inferior pedicle. This study seeks to delineate the complication profiles and outcomes for reduction mammaplasty using a superomedial pedicle technique in a large series., Methods: A retrospective review was conducted of all consecutively performed reduction mammaplasty cases at a single institution by two plastic surgeons over a 2-year period. All consecutive superomedial pedicle reduction mammaplasty cases for benign symptomatic macromastia were included., Results: A total of 462 breasts were analyzed. Mean age was 38.3 ± 13.38 years, mean body mass index was 28.5 ± 4.95, and mean reduction weight was 644.4 ± 299.16 g. Regarding surgical technique, a superomedial pedicle was used in all cases; Wise-pattern incision was used in 81.4%, and short-scar incision was used in 18.6%. The mean sternal notch-to-nipple measurement was 31.2 ± 4.54 cm. There was a 19.7% rate of any complication, the majority of which were minor in nature, including any wound healing complications treated with local wound care (7.5%) and scarring with intervention in the office (8.6%). There was no statistically significant difference in breast reduction complications and outcomes using the superomedial pedicle, regardless of sternal notch-to-nipple distance. Body mass index ( P = 0.029) and breast reduction specimen operative weight ( P = 0.004) were the only significant risk factors for a surgical complication, and with each additional gram of reduction weight, the odds of a surgical complication increased by 1.001. Mean follow-up time was 40.5 ± 7.1 months., Conclusion: The superomedial pedicle is an excellent option for reduction mammaplasty, portending a favorable complication profile and long-term outcomes., Clinical Question/level of Evidence: Therapeutic, IV., (Copyright © 2023 by the American Society of Plastic Surgeons.)
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- 2023
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21. Analysis of Incidentally Found Proliferative Lesions in Oncoplastic and Macromastia Breast Reductions.
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Morrison KA, Choi M, and Karp NS
- Subjects
- Hypertrophy, Female, Humans, Breast surgery, Breast pathology, Breast abnormalities, Middle Aged, Adult, Retrospective Studies, Carcinoma, Intraductal, Noninfiltrating surgery, Mammaplasty adverse effects, Breast Neoplasms epidemiology, Breast Neoplasms surgery, Breast Neoplasms pathology
- Abstract
Background: Reduction mammaplasty pathologic specimens can reveal incidentally found proliferative lesions. However, there is a lack of data investigating the comparative incidences and risk factors for such lesions., Methods: A retrospective review was conducted of all consecutively performed reduction mammaplasty cases at a single large academic medical institution in a metropolitan city by two plastic surgeons over a 2-year period. All reduction mammaplasties, symmetrizing reductions, and oncoplastic reductions performed were included. There were no exclusion criteria., Results: A total of 632 breasts were analyzed-502 reduction mammaplasties, 85 symmetrizing reductions, and 45 oncoplastic reductions-in 342 patients. Mean age was 43.9 ± 15.9 years, mean body mass index was 29.2 ± 5.7 kg/m 2 , and mean reduction weight was 610.0 ± 313.1 g. Patients who underwent reduction mammaplasty for benign macromastia had a significantly lower incidence (3.6%) of incidentally found breast cancers and proliferative lesions compared with patients with oncoplastic reductions (13.3%) and symmetrizing reductions (17.6%) ( P < 0.001). On univariate analysis, personal history of breast cancer ( P < 0.001), first-degree family history of breast cancer ( P = 0.008), age ( P < 0.001), and tobacco use ( P = 0.033) were all statistically significant risk factors. Using a backward elimination stepwise reduced multivariable logistic regression model for risk factors associated with breast cancer or proliferative lesions, age ( P < 0.001) was the only retained significant risk factor., Conclusions: Proliferative lesions and carcinomas of the breast found in reduction mammaplasty pathologic specimens may be more common than previously reported. The incidence of newly found proliferative lesions was significantly lower in cases of benign macromastia compared with oncoplastic and symmetrizing reductions., Clinical Question/level of Evidence: Risk, II., (Copyright © 2023 by the American Society of Plastic Surgeons.)
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- 2023
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22. A novel treatment of pediatric bilateral condylar fractures with lateral dislocation of the temporomandibular joint (TMJ) using transfacial pinning.
- Author
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Morrison KA and Flores RL
- Abstract
A 3-year-old patient sustained a tripartite mandibular fracture, including bilateral condylar fractures with lateral dislocation of the left condyle and symphyseal fracture. Staged lower jaw reconstruction with closed reduction of the laterally dislocated condyle, transfacial pinning between the mandibular angles, MMF using circummandibular wiring and intermaxillary fixation screws was performed., Competing Interests: The authors declared no potential conflicts of interest with respect to the research, authorship, or publication of this article., (© 2023 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.)
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- 2023
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23. Quantifying Surgical Complications for Reduction Mammaplasty in Adolescents.
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Morrison KA, Vernon R, Choi M, and Karp NS
- Subjects
- Adult, Young Adult, Retrospective Studies, Hypertrophy surgery, Adolescent, Female, Humans, Treatment Outcome, Breast surgery, Breast abnormalities, Mammaplasty methods
- Abstract
Background: Reduction mammaplasty is a safe, effective procedure to alleviate symptoms of adolescent macromastia. However, there remain limited data on surgical complications associated with reduction mammaplasty in adolescents, which may not be concordant with those cited for adults seeking reduction mammaplasty., Methods: A retrospective review was conducted of all consecutively performed reduction mammaplasty cases for symptomatic macromastia in patients aged 20 years and younger over a 7-year period from 2014 to 2021., Results: One hundred sixty total breasts were analyzed in 80 patients. Mean age was 18.3 ± 1.4 years, with an age range from 15 to 20 years. Mean body mass index was 27.17 ± 5.49 kg/m 2 . Mean reduction weight was 584.79 ± 261.19 g. A medial pedicle was used in 91%, and an inferior pedicle was used in 9%. For skin incision, a Wise pattern was used in 60%, and a short-scar was used in 40%. There was a 16.3% rate of any surgical complication, which included wound healing by secondary intention treated with local wound care. There were no significant risk factors for a surgical complication in reduction mammaplasty, and no differences in surgical complications related to skin incision type, pedicle use, or breast reduction weight. Performance of a receiver operating characteristic curve for age at surgery and complication demonstrated that there was no age cutoff where the risk of surgical complication was appreciably increased or decreased., Conclusions: Age was not identified as a risk factor for surgical complications in adolescent reduction mammaplasty. Overall, complication rates were very low and minor in nature for adolescent reduction mammaplasty, with no significant risk factors identified., Clinical Question/level of Evidence: Risk, III., (Copyright © 2022 by the American Society of Plastic Surgeons.)
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- 2023
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24. Transpalpebral Eyelid Approach for Supraorbital Frontal Craniotomy and Access to the Anterior Cranial Fossa.
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Morrison KA, Farber SJ, Riina HA, and Staffenberg DA
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- Humans, Male, Female, Adult, Middle Aged, Craniotomy methods, Neurosurgical Procedures, Eyelids surgery, Cranial Fossa, Anterior surgery, Plastic Surgery Procedures
- Abstract
Summary: The transpalpebral eyelid approach is an innovative alternative to traditional incisions for exposure of the anterior cranial fossa for neurosurgery. However, there is a paucity of data on this surgical technique in the plastic surgery literature for accessing the anterior cranial fossa. A retrospective review was performed of patients who underwent supraorbital frontal craniotomy using an anterior skull base approach with transpalpebral exposure over 8 years by a single plastic surgeon. Surgical techniques, medical comorbidities, intraoperative complications, and long-term complications were assessed. Twenty patients (mean age 52 ± 12 years, 55% male, 45% female) underwent supraorbital frontal craniotomy using an anterior skull base approach with upper transpalpebral exposure. Operative indications included the following: 75% had anterior communicating aneurysms, with a mean aneurysm size of 5.36 ± 1.91 mm; 10% had meningiomas; 10% had dural fistulas; and 5% had an orbital hemangioma. A total of 60% of patients had a smoking history. No intraoperative complications were encountered, and no cases required conversion to a traditional open approach. Mean length of hospital stay was 3.2 ± 1.5 days. Postoperative imaging revealed no residual or recurrent pathology. Mean follow-up time was 62.2 ± 30.6 months. No long-term neurologic or ophthalmologic complications or infections occurred. No forehead paresthesias, brow ptosis, or brow paralysis were noted. The transpalpebral technique is a safe, minimally invasive method to approach lesions of the anterior cranial fossa. Successful application may require appropriate management of the frontal sinus and supraorbital nerve. This approach does not limit neurosurgical access or results and led to no neurosurgical complications., Clinical Question/level of Evidence: Therapeutic, IV., Competing Interests: Disclosure:The authors have no financial disclosures or conflicts of interest to report., (Copyright © 2022 by the American Society of Plastic Surgeons.)
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- 2023
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25. Revisiting Reduction Mammaplasty: Complications of Oncoplastic and Symptomatic Macromastia Reductions.
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Morrison KA, Frey JD, Karp N, and Choi M
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- Adult, Nipples surgery, Hypertrophy complications, Retrospective Studies, Breast abnormalities, Female, Humans, Treatment Outcome, Postoperative Complications epidemiology, Postoperative Complications etiology, Postoperative Complications surgery, Middle Aged, Mammaplasty adverse effects, Mammaplasty methods
- Abstract
Background: Oncoplastic breast reduction has been shown to be an effective and safe approach to breast conservation surgery in women with macromastia. However, there remains a paucity of data investigating the comparative outcomes. This study seeks to delineate the complication profiles for oncoplastic and symmetrizing breast reductions versus mammaplasty for benign macromastia., Methods: A retrospective review was conducted of all consecutively performed reduction mammaplasty cases at a single institution by two plastic surgeons over a 2-year period., Results: A total of 632 breasts were analyzed: 502 reduction mammaplasties, 85 symmetrizing reductions, and 45 oncoplastic reductions in 342 patients. Mean age was 43.9 ± 15.93 years, mean body mass index was 29.15 ± 5.66 kg/m2, and mean reduction weight was 610.03 ± 313.13 g. Regarding surgical technique, a medial pedicle was used in 86% of cases. There were similar postoperative complication outcomes for nipple necrosis, wound healing, scar revision, fat necrosis, seroma, hematoma, and overall complication rates for all procedures. However, the rate of postoperative revision among reduction mammaplasty (2%), oncoplastic reduction (6.7%), and symmetrizing reduction (5.9%) was significantly different (P = 0.027). In univariate analysis, diabetes (P = 0.011), smoking (P = 0.007), higher body mass index (P = 0.003), larger reduction weight (P = 0.011), longer nipple-to-inframammary fold measurement (P = 0.014), and longer sternal notch-to-nipple measurement (P = 0.039) were all significant risk factors for a surgical complication in reductions performed for any indication. Using a multivariate logistic regression model, diabetes (P = 0.047), smoking (P = 0.025), and higher body mass index (P = 0.002) were all retained as statistically significant risk factors., Conclusion: The complication profiles for both oncoplastic breast reductions and breast reductions for symptomatic macromastia are similar and acceptably low., Clinical Question/level of Evidence: Therapeutic, III., (Copyright © 2022 by the American Society of Plastic Surgeons.)
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- 2023
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26. Free Fibula Flap for the Treatment of Agnathia in a 10-Year-Old With Severe Agnathia-Otocephaly Complex.
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Cohen O, Morrison KA, Jacobson A, Levine J, and Staffenberg DA
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- Male, Humans, Child, Fibula transplantation, Mandible diagnostic imaging, Mandible surgery, Mandible abnormalities, Microstomia, Craniofacial Abnormalities, Free Tissue Flaps, Jaw Abnormalities surgery, Mandibular Reconstruction
- Abstract
Agnathia-otocephaly complex (AOC), a first branchial arch defect, is characterized by mandibular hypoplasia or aplasia, ear abnormalities, microstomia, and macroglossia and is a rare and often fatal diagnosis. Herein, the technical considerations and details of mandibular reconstruction using virtual surgical planning (VSP) and a vascularized free fibula flap for further mandibular reconstruction in a 10-year-old boy are presented. The patient's preoperative examination was consistent with agnathia (absence of mandibular symphysis, bilateral mandibular bodies, condyles, coronoids, rami, and temporomandibular joint), severe microstomia, and a Tessier # 30 cleft (maintained to allow oral access until later in treatment). Virtual surgical planning was utilized to plan a 3-segment fibula for the reconstruction of the mandibular symphysis and bilateral body segments, and bilateral costochondral grafts were planned for the rami. To the authors' knowledge, this represents the first application of virtual surgical planning for mandibular reconstruction with a vascularized free fibula flap in a pediatric patient with severe agnathia-otocephaly complex., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 by Mutaz B. Habal, MD.)
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- 2023
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27. Vapor detection and vapor pressure measurements of fentanyl and fentanyl hydrochloride salt at ambient temperatures.
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Ewing RG, Nims MK, Morrison KA, Hart GL, Avalos NM, and Denis EH
- Subjects
- Vapor Pressure, Temperature, Analgesics, Opioid analysis, Gases, Fentanyl analysis, Illicit Drugs
- Abstract
There is a need for non-contact, real-time vapor detection of drugs to combat illicit transportation and help curb the opioid epidemic. The low volatility of drugs, like fentanyl, makes room temperature vapor detection of illicit drugs challenging, but feasible by atmospheric flow tube-mass spectrometry (AFT-MS). AFT-MS is a non-contact vapor detection approach capable of ultra-trace detection of drugs, including fentanyl and its analogs at low parts-per-quadrillion (ppq
v ) levels. The determination of vapor pressure values of fentanyl is necessary to understand potential vapor concentrations that may be available for detection. In this paper, vapor pressures of fentanyl free base and fentanyl hydrochloride salt (a common form of the illicit drug) were measured as a function of temperature at or near ambient conditions using the transpiration (gas saturation) method and AFT-MS. Based on our measurements, the vapor pressure of fentanyl at 25 °C is 9.0 × 10-14 atm (90 ppqv ), and the vapor pressure of fentanyl hydrochloride at 25 °C is 1.8 × 10-17 atm (0.018 ppqv ). We also demonstrate non-contact, real-time vapor detection of fentanyl. Preconcentration of vapors can further extend the detection capabilities. The collection, desorption, and detection of fentanyl vapors at ambient conditions was demonstrated for sampling times of seconds to an hour resulting in increased signal. AFT-MS is a viable detection method of fentanyl and other drugs for screening of packages and cargo.- Published
- 2022
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28. Not Just a Linear Closure: Aesthetic Flat Closure after Mastectomy.
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Morrison KA and Karp NS
- Abstract
Currently, there is an increasing trend in women seeking aesthetic flat closure after mastectomy. To date, there is no plastic surgery literature on specific techniques to achieve an aesthetic flat closure after mastectomy. As plastic surgeons, we need to continue to innovate and to iterate new surgical techniques in our reconstructive armamentarium to address the desires of and to optimize the outcomes for our reconstructive breast surgery patients. Herein, we seek to delineate key considerations and employed techniques for reconstructive plastic surgeons performing aesthetic flat closure after mastectomy. Namely, it is crucial to listen to the patient, and to fully understand the patient's concerns, wishes, and particular aesthetic desired. From a technical perspective, the key surgical pearls include completely obliterating the inframammary fold, ensuring the same size and flap thickness bilaterally, appropriately de-fatting medially on the chest wall to allow for a smooth contour, obviating any presence of dog ears medially or laterally with precise tissue excision, and confirming that the incisions are entirely symmetric bilaterally. Intraoperatively, it is important to sit these patients up to assess soft tissue re-draping, and to confirm that there are no dog ears nor any excess tissue that could compromise the perfectly flat aesthetic chest closure. With the increasing demand for flat closures after mastectomy, plastic surgeons need to be keen on employing modified surgical techniques to best optimize the desired aesthetic flat closure reconstructions for these patients, as these reconstructions are not simply linear closures., (Copyright © 2022 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.)
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- 2022
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29. Membrane extraction with styrene-maleic acid copolymer results in insulin receptor autophosphorylation in the absence of ligand.
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Morrison KA, Wood L, Edler KJ, Doutch J, Price GJ, Koumanov F, and Whitley P
- Subjects
- Insulin, Ligands, Maleates pharmacology, Phosphorylation, Polymers, Polystyrenes, Detergents, Receptor, Insulin
- Abstract
Extraction of integral membrane proteins with poly(styrene-co-maleic acid) provides a promising alternative to detergent extraction. A major advantage of extraction using copolymers rather than detergent is the retention of the lipid bilayer around the proteins. Here we report the first functional investigation of the mammalian insulin receptor which was extracted from cell membranes using poly(styrene-co-maleic acid). We found that the copolymer efficiently extracted the insulin receptor from 3T3L1 fibroblast membranes. Surprisingly, activation of the insulin receptor and proximal downstream signalling was detected upon copolymer extraction even in the absence of insulin stimulation. Insulin receptor and IRS1 phosphorylations were above levels measured in the control extracts made with detergents. However, more distal signalling events in the insulin signalling cascade, such as the phosphorylation of Akt were not observed. Following copolymer extraction, in vitro addition of insulin had no further effect on insulin receptor or IRS1 phosphorylation. Therefore, under our experimental conditions, the insulin receptor is not functionally responsive to insulin. This study is the first to investigate receptor tyrosine kinases extracted from mammalian cells using a styrene-maleic acid copolymer and highlights the importance of thorough functional characterisation when using this method of protein extraction., (© 2022. The Author(s).)
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- 2022
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30. Proton Affinity Values of Fentanyl and Fentanyl Analogues Pertinent to Ambient Ionization and Detection.
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Denis EH, Bade JL, Renslow RS, Morrison KA, Nims MK, Govind N, and Ewing RG
- Subjects
- Atmospheric Pressure, Gases analysis, Gases chemistry, Limit of Detection, Protons, Reproducibility of Results, Substance Abuse Detection methods, Fentanyl analogs & derivatives, Fentanyl analysis, Fentanyl chemistry, Mass Spectrometry methods
- Abstract
Proton affinity is a major factor in the atmospheric pressure chemical ionization of illicit drugs. The detection of illicit drugs by mass spectrometry and ion mobility spectrometry relies on the analytes having greater proton affinities than background species. Evaluating proton affinities for fentanyl and its analogues is informative for predicting the likelihood of ionization in different environments and for optimizing the compounds' ionization and detection, such as through the addition of dopant chemicals. Herein, density functional theory was used to computationally determine the proton affinity and gas-phase basicity of 15 fentanyl compounds and several relevant molecules as a reference point. The range of proton affinities for the fentanyl compounds was from 1018 to 1078 kJ/mol. Fentanyl compounds with the higher proton affinity values appeared to form a bridge between the oxygen on the amide and the protonated nitrogen on the piperidine ring based on models and calculated bond distances. Experiments with fragmentation of proton-bound clusters using atmospheric flow tube-mass spectrometry (AFT-MS) provided estimates of relative proton affinities and showed proton affinity values of fentanyl compounds >1000 kJ/mol, which were consistent with the computational results. The high proton affinities of fentanyl compounds facilitate their detection by ambient ionization techniques in complex environments. The detection limits of the fentanyl compounds with AFT-MS are in the low femtogram range, which demonstrates the feasibility of trace vapor drug detection.
- Published
- 2022
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31. Ab initio reconstruction of small angle scattering data for membrane proteins in copolymer nanodiscs.
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Morrison KA, Doekhie A, Neville GM, Price GJ, Whitley P, Doutch J, and Edler KJ
- Abstract
Background: Small angle scattering techniques are beginning to be more widely utilised for structural analysis of biological systems. However, applying these techniques to study membrane proteins still remains problematic, due to sample preparation requirements and analysis of the resulting data. The development of styrene-maleic acid co-polymers (SMA) to extract membrane proteins into nanodiscs for further study provides a suitable environment for structural analysis., Methods: We use small angle neutron scattering (SANS) with three different contrasts to determine structural information for two different polymer nanodisc-incorporated proteins, Outer membrane protein F (OmpF) and gramicidin. Ab initio modelling was applied to generate protein/lipid structures from the SANS data. Other complementary structural methodologies, such as DLS, CD and TEM were compared alongside this data with known protein crystal structures., Results: A single-phase model was constructed for gramicidin-containing nanodiscs, which showed dimer formation in the centre of the nanodisc. For OmpF-nanodiscs we were able to construct a multi-phase model, providing structural information on the protein/lipid and polymer components of the sample., Conclusions: Polymer-nanodiscs can provide a suitable platform to investigate certain membrane proteins using SANS, alongside other structural methodologies. However, differences between the published crystal structure and OmpF-nanodiscs were observed, suggesting the nanodisc structure could be altering the folding of the protein., General Significance: Small angle scattering techniques can provide structural information on the protein and polymer nanodisc without requiring crystallisation of the protein. Additional complementary techniques, such as ab initio modelling, can generate alternative models both the protein and nanodisc system., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (©2021TheAuthors.PublishedbyElsevierB.V.)
- Published
- 2021
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32. Development of Methodology to Investigate the Surface SMALPome of Mammalian Cells.
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Morrison KA, Heesom KJ, Edler KJ, Doutch J, Price GJ, Koumanov F, and Whitley P
- Abstract
Extraction of membrane proteins from biological membranes has traditionally involved detergents. In the past decade, a new technique has been developed, which uses styrene maleic acid (SMA) copolymers to extract membrane proteins into nanodiscs without the requirement of detergents. SMA nanodiscs are compatible with analytical techniques, such as small-angle scattering, NMR spectroscopy, and DLS, and are therefore an attractive medium for membrane protein characterization. While mass spectrometry has also been reported as a technique compatible with copolymer extraction, most studies have focused on lipidomics, which involves solvent extraction of lipids from nanodiscs prior to mass-spectrometry analysis. In this study, mass spectrometry proteomics was used to investigate whether there are qualitative or quantitative differences in the mammalian plasma membrane proteins extracted with SMA compared to a detergent control. For this, cell surface proteins of 3T3L1 fibroblasts were biotinylated and extracted using either SMA or detergent. Following affinity pull-down of biotinylated proteins with NeutrAvidin beads, samples were analyzed by nanoLC-MS. Here, we report for the first time, a global proteomics protocol for detection of a mammalian cell "SMALPome", membrane proteins incorporated into SMA nanodiscs. Removal of SMA from samples prior to processing of samples for mass spectrometry was a crucial step in the protocol. The reported surface SMALPome of 3T3L1 fibroblasts consists of 205 integral membrane proteins. It is apparent that the detergent extraction method used is, in general, quantitatively more efficient at extracting proteins from the plasma membrane than SMA extraction. However, samples prepared following detergent extraction contained a greater proportion of proteins that were considered to be "non-specific" than in samples prepared from SMA extracts. Tantalizingly, it was also observed that proteins detected uniquely or highly preferentially in pull-downs from SMA extracts were primarily multi-spanning membrane proteins. These observations hint at qualitative differences between SMA and detergent extraction that are worthy of further investigation., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Morrison, Heesom, Edler, Doutch, Price, Koumanov and Whitley.)
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- 2021
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33. State of Microsurgery Training in 2020: Survey of Hand Surgery Fellowship Program Directors.
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Morrison KA, Verzella A, and Hacquebord JH
- Subjects
- Education, Medical, Graduate, Hand surgery, Humans, Microsurgery, Surveys and Questionnaires, United States, Fellowships and Scholarships, Orthopedics education
- Abstract
Background: Given the current national conundrum of decreasing microsurgery case volume performed by hand surgery fellows despite interest, program directors were surveyed to evaluate opinions of exposure gaps in training and to determine the current state of microsurgery training in 2020., Methods: Anonymous national surveys were distributed to hand surgery fellowship program directors by the American Society for Surgery of the Hand. Subgroups were compared by training location and size of the fellowship program. Accreditation Council for Graduate Medical Education public national data on graduate case log procedures by hand surgery fellows were reviewed., Results: Eighty-eight surveys were distributed by the American Society for Surgery of the Hand to hand surgery fellowship program directors with a 44% (n = 39) response rate. Hand surgery fellowship programs from 19 US states participated. Most program's fellows had previous orthopedic surgery residency training with 41.03% of programs surveyed having 100% orthopedic surgery-trained fellows. The average number of weekly vascular microsurgical cases ranged from 25% of fellowships having no microsurgery cases per week, 46.2% having 1 per week, and only 7.7% having 5 or more cases per week. However, 60.5% of program directors prioritized a microvascular surgery case as the most valuable educational opportunity for fellows. Most program directors agreed (79.5%) that a 1-year hand surgery fellowship is sufficient to train a competent hand surgeon, who is proficient in microsurgery. In contrast, the majority disagreed (53.8%) that hand surgery microsurgery skills after a 1-year hand surgery fellowship are equivalent among graduates, regardless of a prior plastic surgery or orthopedic surgery residency training. There was a statistically significant difference in program directors' responses by geographic location regarding prior residency background impacting microsurgical skills (Kendall τ, -0.439; P = 0.001). Graduate case log data revealed an increasing trend in the number of microsurgery procedures performed by orthopedic hand surgery fellows until 2014, with a decline in cases per year and stagnating trend at 7% thereafter., Conclusions: In 2020, most hand surgery fellowship program directors highly value and prioritize microsurgery exposure for their hand surgery fellows' education despite the decrease in case volume for hand surgery fellows., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)
- Published
- 2021
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34. Robin Sequence: Neonatal Mandibular Distraction.
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Morrison KA, Collares MV, and Flores RL
- Subjects
- Airway Obstruction surgery, Humans, Infant, Newborn, Osteogenesis, Distraction adverse effects, Osteogenesis, Distraction instrumentation, Postoperative Complications, Treatment Outcome, Mandible surgery, Orthognathic Surgical Procedures methods, Osteogenesis, Distraction methods, Pierre Robin Syndrome surgery
- Abstract
Pierre Robin sequence is defined by the clinical triad: mandibular hypoplasia, glossoptosis, and airway obstruction. Mandibular distraction osteogenesis (MDO) is a standard treatment of Robin sequence associated with severe airway obstruction and is the only intervention that directly corrects the underlying anatomic pathologic condition. Compared with tongue-lip adhesion, MDO has demonstrated more success in treating airway obstruction in infants with Pierre Robin sequence, including patients with syndromic diagnoses and concomitant anomalies. This article provides a current, comprehensive review of neonatal mandibular distraction and offers treatment guidelines based on a combined surgical experience of more than 400 patients., (Copyright © 2021 Elsevier Inc. All rights reserved.)
- Published
- 2021
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35. Non-contact detection of thiodiglycol vapors and associated degradation products using atmospheric flow tube mass spectrometry.
- Author
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Morrison KA and Clowers BH
- Abstract
Thiodiglycol (TDG) is a synthetic precursor and an environmental degradation product of sulfur mustard (HD). Consequently, its presence can be indicative of illicit preparation or historical presence of chemical weapons, but its lower toxicity lends itself to use as an HD simulant for testing and method development. Detection of TDG vapor often proves elusive with existing techniques exhibiting undesirably high detection limits in the gas phase (>ppm). Moreover, traditional approaches to detecting TDG vapor rely upon non-specific approaches that do not provide the certainty afforded by mass spectrometry. Using atmospheric flow tube mass spectrometry (AFT-MS), which has previously demonstrated the capacity to detect parts-per-quadrillion levels of vapor, we evaluate the capacity of this approach for non-contact residue analysis based upon TDG vapor sampling and nitrate clustering chemistry. Furthermore, we discuss challenges with ambient vapor detection using the AFT-MS system and associated observations related to TDG degradation into 2,2'-sulfonyldiglycol from exposure to ambient conditions with vapor detection being possible even after 7-weeks of sample aging.
- Published
- 2021
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36. Trace explosive residue detection of HMX and RDX in post-detonation dust from an open-air environment.
- Author
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Denis EH, Morrison KA, Wharton S, Phillips S, Myers SC, Foxe MP, and Ewing RG
- Abstract
Explosives are often used in industry, geology, mining, and other applications, but it is not always clear what remains after a detonation or the fate and transport of any residual material. The goal of this study was to determine to what extent intact molecules of high explosive (HE) compounds are detectable and quantifiable from post-detonation dust and particulates in a field experiment with varied topography. We focused on HMX (1,3,5,7-Tetranitro-1,3,5,7-tetrazocane), which is less studied in field detonation literature, as the primary explosive material and RDX (1,3,5-Trinitroperhydro-1,3,5-triazine) as the secondary material. The experiment was conducted at Site 300, Lawrence Livermore National Laboratory's Experimental Test Site, in California, USA. Two 20.4 kg and one 40.8 kg above ground explosions (primarily comprised of LX-14, an HMX-based polymer-bonded high explosive) were detonated on an open-air firing area on separate days. The complex terrain of the firing area (e.g., buildings, berm, low-height obstacles) was advantageous to study HE deposition in relation to plume dynamics. Three types of samples were collected up to 100 m away from each shot: surface swipes of aluminum plates, surface swipes of fixed objects, and filters from air samples. We used atmospheric flow tube-mass spectrometry (AFT-MS) to quantify picogram levels of molecular residue of HE material in the post-detonation dust. An aliquot of sample extract in methanol (e.g., 1 μL of 0.5 mL) was placed onto a resistive material and then thermally desorbed into the AFT-MS. We successfully detected and quantified both HMX and RDX in many of the samples. Based on mass (pg) detected and solution dilution, we back-calculated the mass collected on the swipe or filter (ng per sample). The aerial distribution of molecular residue was consistent with the path of the plume, which was strongly determined by wind speed and direction at the time of each shot. The quantity of material detected appeared to correlate more with distance from the shot and the wind conditions than with shot size. This study demonstrates that the picogram detection levels of AFT-MS are well-suited for quantification of analytes (e.g., HMX and RDX) in environmental samples., (Copyright © 2021 Elsevier B.V. All rights reserved.)
- Published
- 2021
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37. Poly-4-hydroxybutyrate (Phasix™) mesh onlay in complex abdominal wall repair.
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Levy AS, Bernstein JL, Premaratne ID, Rohde CH, Otterburn DM, Morrison KA, Lieberman M, Pomp A, and Spector JA
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- Abdominoplasty adverse effects, Adult, Aged, Aged, 80 and over, Female, Hernia, Ventral surgery, Herniorrhaphy adverse effects, Herniorrhaphy instrumentation, Herniorrhaphy methods, Humans, Male, Middle Aged, Postoperative Complications etiology, Reoperation, Seroma etiology, Young Adult, Abdominal Wall surgery, Abdominoplasty instrumentation, Abdominoplasty methods, Polyesters, Surgical Mesh adverse effects
- Abstract
Background: Poly-4-hydroxybutyric acid (P4HB, Phasix™) is a biosynthetic polymer that degrades by hydrolysis that can be woven into a mesh for use in soft tissue reinforcement. Herein, we describe our initial experience performing complex abdominal wall repair (CAWR) utilizing component separation and P4HB mesh as onlay reinforcement., Methods: All patients undergoing CAWR between June 2014 and May 2017 were followed prospectively for postoperative outcomes. Only those patients who underwent components separation with primary repair of the fascial edges followed by onlay of P4HB mesh were included in this study., Results: 105 patients (52 male, 53 female; mean age 59.2 years, range 22-84) met inclusion criteria. Mean BMI was 29.1 (range 16-48); 52% patients had prior attempted hernia repair, most with multiple medical comorbidities (71% of patients with ASA 3 or greater). 30% of cases were not clean at the time of repair (CDC class 2 or greater). Median follow-up was 36 months (range 9-63). Eighteen patients (17%) developed a hernia recurrence ranging from 2 to 36 months postoperatively. Five (5%) patients developed a localized superficial infection treated with antibiotics, three (2.8%) required re-operation for non-healing wounds, and six (6%) patients developed seroma., Conclusions: These data demonstrate a relatively low rate of hernia recurrence, seroma, and other common complications of CAWR in a highly morbid patient population. Importantly, the rate of mesh infection was low and no patients required complete mesh removal, even when placed into a contaminated or infected surgical field.
- Published
- 2021
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38. Ion Mobility Spectrometry Characterization of the Intermediate Hydrogen-Containing Gold Cluster Au 7 (PPh 3 ) 7 H 5 2 .
- Author
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Ligare MR, Morrison KA, Hewitt MA, Reveles JU, Govind N, Hernandez H, Baker ES, Clowers BH, Laskin J, and Johnson GE
- Abstract
We employ ion mobility spectrometry and density functional theory to determine the structure of Au
7 (PPh3 )7 H5 2+ (PPh3 = triphenylphosphine), which was recently identified by high mass resolution mass spectrometry. Experimental ion-neutral collision cross sections represent the momentum transfer between the ionic clusters and gas molecules averaged over the relative thermal velocities of the colliding pair, thereby providing structural insights. Theoretical calculations indicate the geometry of Au7 (PPh3 )7 H5 2+ is similar to Au7 (PPh3 )7 + , with three hydrogen atoms bridging two gold atoms and two hydrogen atoms forming single Au-H bonds. Collision-induced dissociation products observed during IMS experiments reveal that smaller hydrogen-containing clusters may be produced through fragmentation of Au7 (PPh3 )7 H5 2+ . Our findings indicate that hydrogen-containing species like Au7 (PPh3 )7 H5 2+ act as intermediates in the formation of larger phosphine ligated gold clusters. These results advance the understanding and ability to control the mechanisms of size-selective cluster formation, which is necessary for scalable synthesis of clusters with tailored properties.- Published
- 2021
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39. Vapor Pressures of RDX and HMX Explosives Measured at and Near Room Temperature: 1,3,5-Trinitro-1,3,5-triazinane and 1,3,5,7-Tetranitro-1,3,5,7-tetrazocane.
- Author
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Morrison KA, Denis EH, Nims MK, Broderick AM, Fausey RC, Rose HJ, Gongwer PE, and Ewing RG
- Abstract
Knowing accurate saturated vapor pressures of explosives at ambient conditions is imperative to provide realistic boundaries on available vapor for ultra-trace detection. In quantifying vapor content emanating from low-volatility explosives, we observed discrepancies between the quantity of explosive expected based on literature vapor pressure values and the amount detected near ambient temperatures. Most vapor pressure measurements for low-volatility explosives, such as RDX (1,3,5-trinitro-1,3,5-triazinane) and HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocane), have been made at temperatures far exceeding 25 °C and linear extrapolation of these higher temperature trends appears to underestimate vapor pressures near room temperature. Our goal was to measure vapor pressures as a function of temperature closer to ambient conditions. We used saturated RDX and HMX vapor sources at controlled temperatures to produce vapors that were then collected and analyzed via atmospheric flow tube-mass spectrometry (AFT-MS). The parts-per-quadrillion (ppq
v ) sensitivity of AFT-MS enabled measurement of RDX vapor pressures at temperatures as low as 7 °C and HMX vapor pressures at temperatures as low as 40 °C for the first time. Furthermore, these vapor pressures were corroborated with analysis of vapor generated by nebulizing low concentration solutions of RDX and HMX. We report updated vapor pressure values for both RDX and HMX. Based on our measurements, the vapor pressure of RDX at 25 °C is 3 ± 1 × 10-11 atm (i.e., 30 parts per trillion by volume, pptv ), the vapor pressure of HMX is 1.0 ± 0.6 × 10-14 atm (10 ppqv ) at 40 °C and, with extrapolation, HMX has a vapor pressure of 1.0 ± 0.6 × 10-15 atm (1.0 ppqv ) at 25 °C.- Published
- 2021
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40. Facilitated self-assembly of a prevascularized dermal/epidermal collagen scaffold.
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Morrison KA, Weinreb RH, Dong X, Toyoda Y, Jin JL, Bender R, Mukherjee S, and Spector JA
- Subjects
- Fibroblasts, Humans, Keratinocytes, Skin, Tissue Engineering, Collagen, Endothelial Cells, Epidermis, Tissue Scaffolds
- Abstract
Introduction: Resurfacing complex full thickness wounds requires free tissue transfer which creates donor site morbidity. We describe a method to fabricate a skin flap equivalent with a hierarchical microvascular network. Materials & methods: We fabricated a flap of skin-like tissue containing a hierarchical vascular network by sacrificing Pluronic
® F127 macrofibers and interwoven microfibers within collagen encapsulating human pericytes and fibroblasts. Channels were seeded with smooth muscle and endothelial cells. Constructs were topically seeded with keratinocytes. Results: After 28 days in culture, multiphoton microscopy revealed a hierarchical interconnected network of macro- and micro-vessels; larger vessels (>100 μm) were lined with a monolayer endothelial neointima and a subendothelial smooth muscle neomedia. Neoangiogenic sprouts formed in the collagen protodermis and pericytes self-assembled around both fabricated vessels and neoangiogenic sprouts. Conclusion: We fabricated a prevascularized scaffold containing a hierarchical 3D network of interconnected macro- and microchannels within a collagen protodermis subjacent to an overlying protoepidermis with the potential for recipient microvascular anastomosis.- Published
- 2020
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41. Non-contact vapor detection of illicit drugs via atmospheric flow tube-mass spectrometry.
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Morrison KA, Valenzuela BR, Denis EH, Nims MK, Atkinson DA, Clowers BH, and Ewing RG
- Subjects
- Mass Spectrometry, Substance Abuse Detection, Temperature, Explosive Agents, Illicit Drugs
- Abstract
Real-time, non-contact detection of illicit drugs is a desirable goal for the interdiction of these controlled substances, but the relatively low vapor pressures of such species present a challenge for trace vapor detection technologies. The introduction of atmospheric flow tube-mass spectrometry (AFT-MS), which has previously been demonstrated to detect gas-phase analytes at low parts-per-quadrillion levels for explosives and organophosphorus compounds, also enables the potential for non-contact drug detection. With AFT-MS, direct vapor detection of cocaine and methamphetamine from ∼5 μg residues at room temperature is demonstrated herein. Furthermore, thermal desorption of low- to sub-picogram levels of cocaine, methamphetamine, fentanyl, and heroin is observed via AFT-MS using a carrier flow rate of several L min
-1 of air. These low levels can permit non-contact sampling through collection of vapor, effectively preconcentrating the analyte before desorption and analysis. Quantitative evaluation of the thermal desorption approach has yielded limits of detection (LODs) on the order of 10 fg for cocaine and fentanyl, 100 fg for methamphetamine, and 1.6 pg for heroin. The LOD for heroin was lowered to 300 fg by using tributyl phosphate as a dopant to form a proton-bound heterodimer with heroin. When used with AFT-MS, the intentional formation of specific drug-dopant adducts has the potential to enhance detection limits and selectivity of additional drug species. Species that are prone to form adducts present a challenge to analysis, but that difficulty can be overcome by the intentional addition of a dopant. Molecules unlikely to form adducts will remain essentially unimpacted, but the adduct-forming species will interact with the dopant to compress the analyte signal into a single peak. This approach would be valuable in the application of non-contact screening for illicit substances via vapor collection followed by thermal desorption for analysis.- Published
- 2020
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42. Adsorption of a styrene maleic acid (SMA) copolymer-stabilized phospholipid nanodisc on a solid-supported planar lipid bilayer.
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Hall SCL, Clifton LA, Tognoloni C, Morrison KA, Knowles TJ, Kinane CJ, Dafforn TR, Edler KJ, and Arnold T
- Abstract
Over recent years, there has been a rapid development of membrane-mimetic systems to encapsulate and stabilize planar segments of phospholipid bilayers in solution. One such system has been the use of amphipathic copolymers to solubilize lipid bilayers into nanodiscs. The attractiveness of this system, in part, stems from the capability of these polymers to solubilize membrane proteins directly from the host cell membrane. The assumption has been that the native lipid annulus remains intact, with nanodiscs providing a snapshot of the lipid environment. Recent studies have provided evidence that phospholipids can exchange from the nanodiscs with either lipids at interfaces, or with other nanodiscs in bulk solution. Here we investigate kinetics of lipid exchange between three recently studied polymer-stabilized nanodiscs and supported lipid bilayers at the silicon-water interface. We show that lipid and polymer exchange occurs in all nanodiscs tested, although the rate and extent differs between different nanodisc types. Furthermore, we observe adsorption of nanodiscs to the supported lipid bilayer for one nanodisc system which used a polymer made using reversible addition-fragmentation chain transfer polymerization. These results have important implications in applications of polymer-stabilized nanodiscs, such as in the fabrication of solid-supported films containing membrane proteins., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2020
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43. Results of XPAND II: A Multicenter, Prospective, Continued-Access Clinical Trial Using the AeroForm Tissue Expander for Two-Stage Breast Reconstruction.
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Ascherman JA, Zeidler K, Morrison KA, Appel J, Castle J, Chun Y, Colwell A, Mohebali K, Stokes T, and Sudarsky L
- Subjects
- Adult, Aged, Breast surgery, Female, Humans, Mammaplasty methods, Mastectomy adverse effects, Middle Aged, Patient Satisfaction, Prospective Studies, Treatment Outcome, Young Adult, Breast Implants, Breast Neoplasms surgery, Mammaplasty instrumentation, Tissue Expansion Devices
- Abstract
Background: XPAND II was a prospective, multicenter, single-arm, open-label, continued-access study designed to confirm the results from the XPAND study, a multicenter, prospective, randomized study for breast reconstruction. The AeroForm device received clearance from the U.S. Food and Drug Administration in December 2016 based on the results of the pivotal XPAND trial, which compared the AeroForm to saline expanders., Methods: Fifty women were treated in the XPAND II study and implanted with the AeroForm device (86 devices). The study endpoint was successful completion of the second-stage surgery, and secondary endpoints were days to complete expansion and reconstruction, and patient/physician satisfaction. Following implantation, women were administered 10-cc doses of carbon dioxide at home up to three times daily. When adequate expansion was achieved, the expanders were exchanged for standard breast implants., Results: The primary endpoint (successful exchange to standard breast implant, precluding non-device-related failures) is 100 percent. All-cause interim success is 95 percent, with three subjects (four breasts) failing primary exchange because of non-device-related reasons. Median time to complete expansion was 21 days (range, 5 to 117 days). Median time to complete the reconstruction was 112 days (range, 55 to 329 days). Ninety-six percent of the subjects were very or moderately satisfied with the AeroForm expansion process., Conclusions: Results of the XPAND II continued access study confirm and improve on previous results from the randomized trial (XPAND). These results validate that the AeroForm patient-controlled, needle-free carbon dioxide tissue expander is safe and effective for two-stage breast reconstruction., Clinical Question/level of Evidence: Therapeutic, IV.
- Published
- 2020
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44. Interrogating Proton Affinities of Organophosphonate Species Via Atmospheric Flow Tube Mass Spectrometry and Computational Methods.
- Author
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Morrison KA, Bythell BJ, and Clowers BH
- Abstract
Within trace vapor analysis in environmental monitoring, defense, and industry, atmospheric flow tube mass spectrometry (AFT-MS) can fill a role that incorporates non-contact vapor analysis with the selectivity and low detection limits of mass spectrometry. AFT-MS has been applied to quantitating certain explosives by selective clustering with nitrate and more recently applied to detecting tributyl phosphate and dimethyl methylphosphonate as protonated species. Developing AFT-MS methods for organophosphorus species is appealing, given that this class of compounds includes a range of pollutants, chemical warfare agent (CWA) simulants, and CWA degradation products. A key aspect of targeting organophosphorus analytes has included the use of dopant ion chemistry to form adducts that impart additional analytical selectivity. The assessment of potential dopant molecules suited to enhance detection of these compounds is hindered by few published ion thermochemical properties for organophosphorus species, such as proton affinity, which can be used for approximating proton-bound dimer bond strength. As a preliminary investigation for the progression of sensing methods involving AFT-MS, we have applied both the extended kinetic method and computational approaches to eight organophosphorus CWA simulants to determine their respective gas-phase proton affinities. Notable observed trends, supported by computational efforts, include an increase in proton affinity as the alkyl chain lengths on the phosphonates increased. Graphical Abstract .
- Published
- 2019
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45. Microstructured hydrogel scaffolds containing differential density interfaces promote rapid cellular invasion and vascularization.
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Celie KB, Toyoda Y, Dong X, Morrison KA, Zhang P, Asanbe O, Jin JL, Hooper RC, Zanotelli MR, Kaymakcalan O, Bender RJ, and Spector JA
- Subjects
- Animals, Male, Mice, Microspheres, Hydrogels chemistry, Hydrogels pharmacology, Materials Testing, Neovascularization, Physiologic drug effects, Skin blood supply, Skin metabolism, Skin pathology, Tissue Scaffolds, Wound Healing drug effects
- Abstract
Introduction: Insufficient vascularization of currently available clinical biomaterials has limited their application to optimal wound beds. We designed a hydrogel scaffold with a unique internal microstructure of differential collagen densities to induce cellular invasion and neovascularization., Methods: Microsphere scaffolds (MSS) were fabricated by encasing 1% (w/v) type 1 collagen microspheres 50-150 μm in diameter in 0.3% collagen bulk. 1% and 0.3% monophase collagen scaffolds and Integra® disks served as controls. Mechanical characterization as well as in vitro and in vivo invasion assays were performed. Cell number and depth of invasion were analyzed using Imaris™. Cell identity was assessed immunohistochemically., Results: In vitro, MSS exhibited significantly greater average depth of cellular invasion than Integra® and monophase collagen controls. MSS also demonstrated significantly higher cell counts than controls. In vivo, MSS revealed significantly more cellular invasion spanning the entire scaffold depth at 14 days than Integra®. CD31+ expressing luminal structures suggestive of neovasculature were seen within MSS at 7 days and were more prevalent after 14 days. Multiphoton microscopy of MSS demonstrated erythrocytes within luminal structures after 14 days., Conclusion: By harnessing simple architectural cues to induce cellular migration, MSS holds great potential for clinical translation as the next generation dermal replacement product., Statement of Significance: Large skin wounds require tissue engineered dermal substitutes in order to promote healing. Currently available dermal replacement products do not always adequately incorporate into the body, especially in complex wounds, due to poor neovascularization. In this paper, we present a hydrogel with an innovative microarchitecture that is composed of dense type I collagen microspheres suspended in a less-dense collagen bulk. We show that cell invasion into the scaffold is driven solely by mechanical cues inherent within this differential density interface, and that this induces robust vascular cell invasion both in vitro and in a rodent model. Our hydrogel performs favorably compared to the current clinical gold standard, Integra®. We believe this hydrogel scaffold may be the first of the next generation of dermal replacement products., (Copyright © 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2019
- Full Text
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46. Ambient vapor sampling and selective cluster formation for the trace detection of tributyl phosphate via atmospheric flow tube mass spectrometry.
- Author
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Morrison KA, Ewing RG, and Clowers BH
- Abstract
In addition to serving as an f-element ligand and rare-earth method complexing agent, tributyl phosphate is a compound containing core functional groups that mimic those routinely found in degradation products from industrial processes. Because detection of trace quantities of tributyl phosphate can provide insight into the routes of contamination and degradation in the environment, there is a need to develop methods capable of detecting trace quantities of tributyl phosphate. Vapor detection at atmospheric pressure is one approach that is both sensitive and rapid. We present here the use of atmospheric flow tube mass spectrometry for the ambient vapor sampling of tributyl phosphate from headspace of ppb-level solutions in methanol. Gas phase clustering reactions were to enhance detection levels via the addition of small quantities of the dopants diethylamine, triethylamine, and pinacolyl methylphosphonate in the vapor stream. Detection of the tributyl phosphate vapor emanating from these solutions demonstrated a linear range for the protonated tributyl phosphate species of 1-1000 ppb from solution. The clusters of tributyl phosphate with diethylamine, triethylamine, and pinacolyl phosphonate each yielded linear ranges of 1-250 ppb for tributyl phosphate in solution. Despite smaller linear ranges, the addition of these dopant species added a layer of analytical selectivity and reduced variability in signals from quality control samples. These data were obtained using an atmospheric flow tube source coupled to a linear ion trap mass spectrometer, which demonstrates the applicability of trapping systems to the atmospheric flow tube ionization technique while monitoring positive ions., (Published by Elsevier B.V.)
- Published
- 2019
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47. Optimized Reconstruction Techniques for Multiplexed Dual-Gate Ion Mobility Mass Spectrometry Experiments.
- Author
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Davis AL, Reinecke T, Morrison KA, and Clowers BH
- Abstract
When coupling drift-tube gas-phase ion mobility separations with ion trapping mass analyzers an integrative, stepped approach to spectral reconstruction is a logical, yet highly inefficient means to determine gas-phase mobility coefficients. This experimental mode is largely predicated on the respective time scales of the two techniques each requiring tens of milliseconds to complete under routine conditions. Multiplexing techniques, such as Fourier and Hadamard based techniques, are a potential solution but still require extended experimental times that are not fully compatible with modern front-end separation schemes. Using a basis pursuit denoising (BPDN) approach to deconvolute Fourier transform ion mobility mass spectrometry (FT-IMMS) drift time spectra, we demonstrate significant time savings while maintaining a high degree of spectral resolution and signal-to-noise ratio. Under ideal conditions, the FT-IMMS operates with increased ion transmission (up to 25%); however, the linear chirp that spans into the kHz range often leads to significant levels of ion gate depletion, which limit both resolving power and ion transmission. The method proposed in this manuscript demonstrates the potential to reduce IMS acquisition time while simultaneously maximizing spectral resolution at longer effective gate pulse widths compared to the traditional set of multiplexing and signal averaging experiments.
- Published
- 2019
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48. Tissue engineering the human auricle by auricular chondrocyte-mesenchymal stem cell co-implantation.
- Author
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Cohen BP, Bernstein JL, Morrison KA, Spector JA, and Bonassar LJ
- Subjects
- Animals, Chondrocytes cytology, Chondrocytes transplantation, Congenital Microtia physiopathology, Disease Models, Animal, Ear Auricle growth & development, Ear Auricle physiopathology, Ear Cartilage growth & development, Ear Cartilage physiopathology, Extracellular Matrix genetics, Extracellular Matrix physiology, Humans, Mesenchymal Stem Cells cytology, Mice, Rats, Tissue Engineering methods, Tissue Scaffolds, Congenital Microtia therapy, Ear Auricle transplantation, Ear Cartilage transplantation, Mesenchymal Stem Cell Transplantation
- Abstract
Children suffering from microtia have few options for auricular reconstruction. Tissue engineering approaches attempt to replicate the complex anatomy and structure of the ear with autologous cartilage but have been limited by access to clinically accessible cell sources. Here we present a full-scale, patient-based human ear generated by implantation of human auricular chondrocytes and human mesenchymal stem cells in a 1:1 ratio. Additional disc construct surrogates were generated with 1:0, 1:1, and 0:1 combinations of auricular chondrocytes and mesenchymal stem cells. After 3 months in vivo, monocellular auricular chondrocyte discs and 1:1 disc and ear constructs displayed bundled collagen fibers in a perichondrial layer, rich proteoglycan deposition, and elastin fiber network formation similar to native human auricular cartilage, with the protein composition and mechanical stiffness of native tissue. Full ear constructs with a 1:1 cell combination maintained gross ear structure and developed a cartilaginous appearance following implantation. These studies demonstrate the successful engineering of a patient-specific human auricle using exclusively human cell sources without extensive in vitro tissue culture prior to implantation, a critical step towards the clinical application of tissue engineering for auricular reconstruction., Competing Interests: LJB is a co-founder and equity holder in 3D BioCorp. Remaining authors declare no competing interests. This does not alter our adherence to PLOS ONE policies on sharing data and materials.
- Published
- 2018
- Full Text
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49. Financial Implications of Atypical Mycobacterial Infections After Cosmetic Tourism: Is It Worth the Risk?
- Author
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Lee JC, Morrison KA, Maeng MM, Ascherman JA, and Rohde CH
- Subjects
- Adult, Colombia, Cosmetic Techniques adverse effects, Cost Savings statistics & numerical data, Cost-Benefit Analysis, Dominican Republic, Female, Humans, Middle Aged, Mycobacterium Infections, Nontuberculous diagnosis, Mycobacterium Infections, Nontuberculous etiology, Mycobacterium Infections, Nontuberculous therapy, New York City, Retrospective Studies, Risk, Surgical Wound Infection diagnosis, Surgical Wound Infection therapy, Cosmetic Techniques economics, Health Care Costs statistics & numerical data, Medical Tourism economics, Mycobacterium Infections, Nontuberculous economics, Surgical Wound Infection economics
- Abstract
Background: Cosmetic tourism has become increasingly popular despite many associated risks. The economic impact of atypical mycobacterial infections in cosmetic tourism is poorly defined in the literature. We sought to investigate the costs and clinical course of patients with these infections., Methods: A retrospective review of all patients managed by the Plastic Surgery Division at Columbia University Medical Center from 2013 to 2014 with atypical mycobacterial surgical site infections after cosmetic surgery outside the United States was performed. Data including patient demographics, procedure costs, clinical course, impact on daily life, and costs associated with complications were collected using hospital billing information, patient questionnaires, telephone interviews, and clinical charts. Cost analysis was done to identify the personal and societal costs of these complications., Results: Data from 10 patients were collected and analyzed. Management of mycobacterial infections cost an average of $98,835.09 in medical charges. The indirect cost of these infections was $24,401 with a mean return to work time of 6.7 months. Total patient savings from cosmetic tourism was $3419. The total cost of a mycobacterial infection was greater than $123,236.47. Although the incidence of mycobacterial infection abroad is unknown, the potential cost of an infection alone outweighs the financial benefits of cosmetic tourism if the risk exceeds 2.77%., Conclusions: Atypical mycobacterial infections as a result of cosmetic tourism come at considerable cost to patients and the health care system. When our results are taken into consideration with other risks of cosmetic tourism, the financial risks likely far outweigh the benefits.
- Published
- 2018
- Full Text
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50. Characterization of alkylphosphonic acid vapors using atmospheric flow tube-ion trap mass spectrometry.
- Author
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Morrison KA and Clowers BH
- Abstract
Rationale: A key aspect of detecting hazardous compounds at ultra-trace levels for processing, compliance, and clean-up purposes involves developing methods that are not only sensitive, but also highly selective with minimal sampling effort. Atmospheric flow tube mass spectrometry (AFT-MS) using dielectric barrier discharge ionization has emerged as a technique that combines such features for vapor detection. AFT-MS is thus appealing for application to ambient screening for chemical warfare agents (CWAs) and their degradation products. Initial characterization of AFT-MS for CWA detection necessitates examining less harmful simulant species. A predominant hydrolysis product of most organophosphorus CWAs is methylphosphonic acid and most other hydrolysis products consist of some form of an alkylphosphonic acid., Methods: An application of AFT-MS is presented wherein a homologous series of four alkylphosphonic acids (methyl-, ethyl-, propyl-, and t-butylphosphonic acid) were first qualitatively evaluated as anionic clusters with nitrate. These anionic adducts were subsequently quantified from non-equilibrium headspace vapor sampled over alkylphosphonic acid solutions in methanol., Results: The series of phosphonic acids demonstrated consistent relative ion abundances thought to be related at least in part to the relative vapor pressures depending on their alkyl chains. For quantitation, the resulting linear ranges were found to be 2 to 50 ppm
soln for methylphosphonic acid, 5 to 50 ppmsoln for ethylphosphonic acid, and 2 to 25 ppmsoln for propylphosphonic acid and t-butylphosphonic acid; quality controls of 15 ppmsoln were used to assess the quantitation accuracy., Conclusions: Although measured over a limited dynamic range, the real-time analysis afforded by this method suggests the feasibility of using thermodynamically stable anionic adducts to monitor organophosphorus compounds via AFT-MS. In addition, this is proof-of-concept for the use of this ambient sensing technique to detect phosphonic acids. Furthermore, a discussion is included regarding gaps in clustering thermodynamics literature that would assist in uncovering physical or chemical explanations for observed trends., (© 2018 John Wiley & Sons, Ltd.)- Published
- 2018
- Full Text
- View/download PDF
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