27 results on '"Porter SJ"'
Search Results
2. Inelastic exchange scattering at surfaces
- Author
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Matthew, JAD, primary and Porter, SJ, additional
- Published
- 1988
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3. Connecting Scientometrics: Dimensions as a Route to Broadening Context for Analyses.
- Author
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Porter SJ and Hook DW
- Abstract
Modern cloud-based data infrastructures open new vistas for the deployment of scientometric data into the hands of practitioners. These infrastructures lower barriers to entry by making data more available and compute capacity more affordable. In addition, if data are prepared appropriately, with unique identifiers, it is possible to connect many different types of data. Bringing broader world data into the hands of practitioners (policymakers, strategists, and others) who use scientometrics as a tool can extend their capabilities. These ideas are explored through connecting Dimensions and World Bank data on Google BigQuery to study international collaboration between countries of different economic classification., Competing Interests: SP and DH were employed by Digital Science, the creator and provider of Dimensions., (Copyright © 2022 Porter and Hook.)
- Published
- 2022
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4. Measuring Research Information Citizenship Across ORCID Practice.
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Porter SJ
- Abstract
Over the past 10 years, stakeholders across the scholarly communications community have invested significantly not only to increase the adoption of ORCID adoption by researchers, but also to build the broader infrastructures that are needed both to support ORCID and to benefit from it. These parallel efforts have fostered the emergence of a "research information citizenry" between researchers, publishers, funders, and institutions. This paper takes a scientometric approach to investigating how effectively ORCID roles and responsibilities within this citizenry have been adopted. Focusing specifically on researchers, publishers, and funders, ORCID behaviors are measured against the approximated research world represented by the Dimensions dataset., Competing Interests: SP was employed by Digital Science., (Copyright © 2022 Porter.)
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- 2022
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5. Improving phylogenetic resolution of the Lamiales using the complete plastome sequences of six Penstemon species.
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Stettler JM, Stevens MR, Meservey LM, Crump WW, Grow JD, Porter SJ, Love LS, Maughan PJ, and Jellen EN
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- Lamiales classification, Penstemon classification, Phylogeny, DNA, Plant genetics, Evolution, Molecular, Genome, Plastid, Lamiales genetics, Penstemon genetics, Plastids genetics
- Abstract
The North American endemic genus Penstemon (Mitchell) has a recent geologic origin of ca. 3.6 million years ago (MYA) during the Pliocene/Pleistocene transition and has undergone a rapid adaptive evolutionary radiation with ca. 285 species of perennial forbs and sub-shrubs. Penstemon is divided into six subgenera occupying all North American habitats including the Arctic tundra, Central American tropical forests, alpine meadows, arid deserts, and temperate grasslands. Due to the rapid rate of diversification and speciation, previous phylogenetic studies using individual and concatenated chloroplast sequences have failed to resolve many polytomic clades. We investigated the efficacy of utilizing the plastid genomes (plastomes) of 29 species in the Lamiales order, including five newly sequenced Penstemon plastomes, for analyzing phylogenetic relationships and resolving problematic clades. We compared whole-plastome based phylogenies to phylogenies based on individual gene sequences (matK, ndhF, psaA, psbA, rbcL, rpoC2, and rps2) and concatenated sequences. We also We found that our whole-plastome based phylogeny had higher nodal support than all other phylogenies, which suggests that it provides greater accuracy in describing the hierarchal relationships among taxa as compared to other methods. We found that the genus Penstemon forms a monophyletic clade sister to, but separate from, the Old World taxa of the Plantaginaceae family included in our study. Our whole-plastome based phylogeny also supports the rearrangement of the Scrophulariaceae family and improves resolution of major clades and genera of the Lamiales., Competing Interests: The authors have declared that no competing interests exist.
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- 2021
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6. Scaling Scientometrics: Dimensions on Google BigQuery as an Infrastructure for Large-Scale Analysis.
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Hook DW and Porter SJ
- Abstract
Cloud computing has the capacity to transform many parts of the research ecosystem, from particular research areas to overall strategic decision making and policy. Scientometrics sits at the boundary between research and the decision-making, policy-making, and evaluation processes that underpin research. One of the biggest challenges in research policy and strategy is having access to data in a way that allows for analysis that can respond in an iterative way to inform decisions. Many decisions are based on "global" measures such as benchmark metrics that are hard to source and hence are often nonspecific or outdated. The use of cloud technologies may be promising in addressing this area of providing data for research strategy and policy decisions. A novel visualisation technique is introduced and used as a means to explore the potential for scaling scientometrics by democratising both access to data and compute capacity using the cloud., Competing Interests: The authors declare that this study was funded by Digital Science. Both authors and investigators are employees of Digital Science and the investigations presented here were undertaken as part of the normal operation of the business. No special funding or conditions were attached to this work., (Copyright © 2021 Hook and Porter.)
- Published
- 2021
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7. Real-Time Bibliometrics: Dimensions as a Resource for Analyzing Aspects of COVID-19.
- Author
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Hook DW, Porter SJ, Draux H, and Herzog CT
- Abstract
Dimensions was built as a platform to allow stakeholders in the research community, including academic bibliometricians, to more easily create and understand the context of different types of research object through the linkages between these objects. Links between objects are created via persistent identifiers and machine learning techniques, while additional context is introduced via data enhancements such as per-object categorisations and person and institution disambiguation. While these features make analytical use cases accessible for end users, the COVID-19 crisis has highlighted a different set of needs to analyze trends in scholarship as they occur: Real-time bibliometrics. The combination of full-text search, daily data updates, a broad set of scholarly objects including pre-prints and a wider set of data fields for analysis, broadens opportunities for a different style of analysis. A subset of these emerging capabilities is discussed and three basic analyses are presented as illustrations of the potential for real-time bibliometrics., Competing Interests: All co-authors of this paper are employees of Digital Science, the creator and provider of Dimensions., (Copyright © 2021 Hook, Porter, Draux and Herzog.)
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- 2021
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8. Clinical Use of the Automated Neuropsychological Assessment Metrics TBI-Mil Expanded Battery in Evaluating Concussion Recovery: A Retrospective Study.
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Porter SJ and Johnson DE
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- Athletic Injuries, Benchmarking, Female, Humans, Male, Military Personnel, Neuropsychological Tests, Reaction Time, Retrospective Studies, Brain Concussion complications, Brain Concussion diagnosis
- Abstract
Introduction: This retrospective study evaluated the use of the Automated Neuropsychological Assessment Metrics (ANAM4) Expanded battery in a clinical setting to determine if the resolution of physiological symptoms, in the absence of neurocognitive assessment, was sufficient data in the return-to-duty (RTD) determination., Materials and Methods: In this study, 508 U.S. Naval Academy midshipmen were diagnosed with concussion and prescribed a standard treatment protocol. As directed by the protocol, they were evaluated and tracked by medical providers until determined to have normal balance and to be asymptomatic at rest and with exertion. Upon the resolution of these physiological symptoms, the midshipmen were referred for neurocognitive (ANAM4) testing. When results indicated a return to neurocognitive baseline, a RTD determination was made., Results: The analysis of data in this study indicated that RTD determinations based solely on the resolution of physiological symptoms would have resulted in 25.1% of the sample being returned to duty before neurocognitive recovery. Additional analysis of the ANAM4 reliable change index (RCI) data for each of the concussed patients revealed a pattern of scores that correlated with an expected length of recovery. Individuals with at least one RCI greater than or equal to -1.64 returned to neurocognitive baseline in 8.92 days, whereas individuals with 2 or more RCIs greater than or equal to -1.25 (but less than -1.64) returned to baseline in 5.78 days, and those with a difference in measured reaction times that were greater or equal to -1.25 returned to baseline in 3.20 days. Furthermore, findings indicated that female service members required additional time for the resolution of physical symptoms as compared to their male counterparts. The mean number of days from injury to being deemed symptoms free in males was approximately 14, as compared to females who were deemed symptom free in 21 days. This difference is statistically significant., Conclusions: Findings of this investigation revealed three specific outcomes. First, a computerized neurocognitive assessment instrument should be used as an adjunct measure in evaluating the resolution of physiological symptoms following a concussive injury. Second, results revealed that based on the RCIs of postinjury ANAM4 assessments, it is possible to estimate the remaining recovery time needed for a return to neurocognitive baseline. Third, results of this analysis revealed that gender appears to be a factor in time between concussive injury and resolution of symptoms., (© The Author(s) 2020. Published by Oxford University Press on behalf of Association of Military Surgeons of the United States. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
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- 2020
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9. Prevalence of Covid-19 Infection and Subsequent Cohorting in a Residential Substance Use Treatment Program in Boston, MA.
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Barocas JA, Blackstone E, Bouton TC, Kimmel SD, Caputo A, Porter SJ, and Walley AY
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- Adult, Betacoronavirus genetics, Boston epidemiology, COVID-19, COVID-19 Testing, Clinical Laboratory Techniques, Coronavirus Infections diagnosis, Coronavirus Infections genetics, Female, Humans, Pandemics, Prevalence, SARS-CoV-2, Young Adult, Coronavirus Infections epidemiology, Health Personnel statistics & numerical data, Pneumonia, Viral epidemiology, Residential Treatment statistics & numerical data, Substance Abuse Treatment Centers statistics & numerical data
- Abstract
Objectives: The global pandemic of coronavirus disease 2019 (Covid-19) may disproportionately affect persons in congregate settings, including those in residential substance use treatment facilities. To limit the spread of SARS-CoV-2 through congregate settings, universal testing may be necessary. We aimed to determine the point prevalence of SARS-CoV-2 in a residential treatment program setting and to understand the unique challenges of Covid-19 transmission in this setting., Methods: We performed a case series of SARS-CoV-2 rT-PCR testing via nasopharyngeal in a residential substance use treatment program for women in Boston. Staff and residents of the treatment program were tested for SARS-CoV-2. The primary outcome was SARS-CoV-2 test result., Results: A total of 31 residents and staff were tested. Twenty-seven percent (6/22) of the residents and 44% (4/9) of staff tested positive for SARS-CoV-2. All of the SARS-CoV-2 positive residents resided in the same residential unit. Two positive cases resided together with 2 negative cases in a 4-person room. Two other positive cases resided together in a 2-person room. One positive case resided with 2 negative cases in a 3-person room. One positive case resided with a negative case in a 2-person room. Based on test results, residents were cohorted by infection status and continued to participate in addiction treatment on-site., Conclusions: SARS-CoV-2 infection was common among staff and residents within a residential substance use treatment program for women in Boston. Universal SARS-CoV-2 testing in residential substance use programs can be instituted to reduce the risk of further transmission and continue addiction treatment programming when accompanied by adequate space, supplies, and staffing.
- Published
- 2020
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10. High-Q Tuneable 10-GHz Bragg Resonator for Oscillator Applications.
- Author
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Bale SJ, Deshpande PD, Hough M, Porter SJ, and Everard JKA
- Abstract
This paper describes the design, simulation, and measurement of a tuneable 9.365-GHz aperiodic Bragg resonator. The resonator utilizes an aperiodic arrangement of non ( /4) low-loss alumina plates ( , loss tangent of to ) mounted in a cylindrical metal waveguide. Tuning is achieved by varying the length of the center section of the cavity. A multi-element bellows/probe assembly is presented. A tuning range of 130 MHz (1.39%) is demonstrated. The insertion loss varies from -2.84 to -12.03 dB while the unloaded Q varies from 43 788 to 122 550 over this tuning range. At 10 of the 13 measurement points, the unloaded Q exceeds 1 00 000, and the insertion loss is above -7 dB. Two modeling techniques are discussed; these include a simple ABCD circuit model for rapid simulation and optimization and a 2.5-D field solver, which is used to plot the field distribution inside the cavity.
- Published
- 2018
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11. The 18-month impact of special supplemental nutrition program for women, infants, and children food package revisions on diets of recipient families.
- Author
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Kong A, Odoms-Young AM, Schiffer LA, Kim Y, Berbaum ML, Porter SJ, Blumstein LB, Bess SL, and Fitzgibbon ML
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- Adult, Chicago, Child, Preschool, Energy Intake, Feeding Behavior, Female, Humans, Infant, Longitudinal Studies, Male, Prospective Studies, Young Adult, Black or African American statistics & numerical data, Diet standards, Food Assistance standards, Hispanic or Latino statistics & numerical data
- Abstract
Background: Beginning in 2009, the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) revised its food packages and provided more whole grains, fruits, and vegetables and fewer foods with high saturated fat content. However, knowledge of the impact of this policy shift on the diets of WIC participants remains limited., Purpose: To examine the longer-term impact of the 2009 WIC food package change on nutrient and food group intake and overall diet quality among African American and Hispanic WIC child participants and their mothers/caregivers., Methods: In this natural experiment, 24-hour dietary recalls were collected in the summer of 2009, immediately before WIC food package revisions occurred in Chicago IL and at 18 months following the food package change (winter/spring 2011). Generalized estimating equation models were used to compare dietary intake at these two time points. Data were analyzed in July 2013., Results: Eighteen months following the WIC food package revisions, significant decreases in total fat (p=0.002) and saturated fat (p=0.0004) and increases in dietary fiber (p=0.03) and overall diet quality (p=0.02) were observed among Hispanic children only. No significant changes in nutrient intake or diet quality were observed for any other group. The prevalence of reduced-fat milk intake significantly increased for African American and Hispanic children, whereas the prevalence of whole milk intake significantly decreased for all groups., Conclusions: Positive dietary changes were observed at 18 months post policy implementation, with the effects most pronounced among Hispanic children., (Copyright © 2014 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.)
- Published
- 2014
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12. Evaluating the initial impact of the revised Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) food packages on dietary intake and home food availability in African-American and Hispanic families.
- Author
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Odoms-Young AM, Kong A, Schiffer LA, Porter SJ, Blumstein L, Bess S, Berbaum ML, and Fitzgibbon ML
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- Animals, Anthropometry, Chicago, Child, Preschool, Cross-Sectional Studies, Diet, Edible Grain, Female, Fruit, Humans, Infant, Life Style, Mental Recall, Milk chemistry, Self Report, Socioeconomic Factors, Vegetables, Black or African American, Energy Intake, Feeding Behavior ethnology, Food Assistance statistics & numerical data, Food Supply statistics & numerical data, Hispanic or Latino
- Abstract
Objective: The present study assessed the impact of the 2009 food packages mandated by the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) on dietary intake and home food availability in low-income African-American and Hispanic parent/child dyads., Design: A natural experiment was conducted to assess if the revised WIC food package altered dietary intake, home food availability, weight and various lifestyle measures immediately (6 months) following policy implementation., Setting: Twelve WIC clinics in Chicago, IL, USA., Subjects: Two hundred and seventy-three Hispanic and African-American children aged 2-3 years, enrolled in WIC, and their mothers., Results: Six months after the WIC food package revisions were implemented, we observed modest changes in dietary intake. Fruit consumption increased among Hispanic mothers (mean = 0·33 servings/d, P = 0·04) and low-fat dairy intake increased among Hispanic mothers (0·21 servings/d, P = 0·02), Hispanic children (0·34 servings/d, P < 0·001) and African-American children (0·24 servings/d, P = 0·02). Home food availability of low-fat dairy and whole grains also increased. Dietary changes, however, varied by racial/ethnic group. Changes in home food availability were not significantly correlated with changes in diet., Conclusions: The WIC food package revisions are one of the first efforts to modify the nutrition guidelines that govern foods provided in a federal food and nutrition assistance programme. It will be important to examine the longer-term impact of these changes on dietary intake and weight status.
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- 2014
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13. Racial/ethnic differences in dietary intake among WIC families prior to food package revisions.
- Author
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Kong A, Odoms-Young AM, Schiffer LA, Berbaum ML, Porter SJ, Blumstein L, and Fitzgibbon ML
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- Adult, Chicago, Child, Preschool, Diet Surveys, Feeding Behavior ethnology, Female, Humans, Infant, Infant, Newborn, Male, Mother-Child Relations, Poverty, Pregnancy, Black or African American statistics & numerical data, Diet ethnology, Diet statistics & numerical data, Hispanic or Latino statistics & numerical data, Public Assistance
- Abstract
Objective: To compare the diets of African American and Hispanic families in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) prior to the 2009 food package revisions., Methods: Mother-child dyads were recruited from 12 WIC sites in Chicago, IL. Individuals with 1 valid 24-hour recall were included in the analyses (n = 331 children, n = 352 mothers)., Results: Compared to their African American counterparts, diets of Hispanic mothers and children were lower (P < .001) in percentage of calories from fat, added sugars, sodium, and sweetened beverages, but higher (P < .001) in vitamin A, calcium, whole grains, fruit, and total dairy. However, no groups met national recommendations for percentage of calories from saturated fat, fiber, sodium, whole grains, vegetables, and total dairy., Conclusions and Implications: There are racial/ethnic differences in dietary intake, and future research is needed to determine whether diets improve as a result of package revisions and whether uptake of these changes varies by race/ethnicity., (Copyright © 2013 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.)
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- 2013
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14. Your Guide to Diet and Diabetes: web-based diabetes education tailored to Hispanics.
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Porter SJ, Chapman-Novakofski KM, and Scherer JA
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- Blood Glucose analysis, Diabetes Mellitus, Type 2 blood, Diabetes Mellitus, Type 2 rehabilitation, Diet, Diabetic, Education, Distance, Feeding Behavior psychology, Health Education methods, Humans, Internet, Diabetes Mellitus, Type 2 diet therapy, Hispanic or Latino education, Hispanic or Latino psychology, Nutritional Sciences education, Patient Education as Topic
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- 2009
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15. In vivo and in vitro potency studies of 6beta-naltrexol, the major human metabolite of naltrexone.
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Porter SJ, Somogyi AA, and White JM
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- Animals, Culture Techniques, Dose-Response Relationship, Drug, Guinea Pigs, Ileum drug effects, Isometric Contraction drug effects, Male, Mice, Gastrointestinal Motility drug effects, Naloxone pharmacology, Naltrexone analogs & derivatives, Naltrexone pharmacology, Narcotic Antagonists pharmacology, Pain Threshold drug effects, Receptors, Opioid, mu drug effects
- Abstract
Naltrexone, a mu opioid receptor antagonist, is used in the treatment of opioid and alcohol dependence. Naltrexone's longer duration of action compared to naloxone has been considered to be due partly to its major human metabolite, 6beta-naltrexol. To date, no studies have examined the in vitro or in vivo potency of 6beta-naltrexol compared to naltrexone and naloxone. In the electrically-stimulated guinea pig ileum, 6beta-naltrexol was more potent (K(i) = 94 +/- 25 pM), than naloxone (420 +/- 150 pM), and naltrexone (265 +/- 101 pM). In vivo comparative potencies were assessed using the mouse hotplate test and morphine (agonist), with doses of the antagonists from 0.001 to 30 mg/kg. The order of potency was naltrexone (ID(50) 7 microg/kg), naloxone (ID(50) 16 microg/kg) and 6beta-naltrexol (ID(50) 1300 microg/kg). Antagonist ID(50) doses were then administered at 45, 90, 120, 180 and 1080 minutes prior to morphine administration. The duration of antagonist activity to decrease by 50% was 80, 125 and 340 minutes for naltrexone, naloxone and 6beta-naltrexol, respectively. 6beta-naltrexol is highly potent in the guinea pig ileum, but much less so in vivo after an acute dose. However, the potency of 6beta-naltrexol in vivo is time-dependent, and it has a longer duration of action than naloxone and naltrexone, consistent with a pharmacokinetic longer terminal half-life. Therefore, 6beta-naltrexol is likely to contribute to the efficacy of naltrexone in humans.
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- 2002
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16. Kinetics and inhibition of the formation of 6beta-naltrexol from naltrexone in human liver cytosol.
- Author
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Porter SJ, Somogyi AA, and White JM
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- Adult, Aged, Analgesics, Opioid pharmacology, Benzodiazepines pharmacology, Chromatography, High Pressure Liquid, Corticosterone pharmacology, Cytosol drug effects, Cytosol enzymology, Cytosol metabolism, Dihydrotestosterone pharmacology, Enzyme Inhibitors pharmacology, Humans, Kinetics, Liver drug effects, Microsomes, Liver drug effects, Microsomes, Liver enzymology, Microsomes, Liver metabolism, Middle Aged, Naloxone pharmacology, Naltrexone antagonists & inhibitors, Naltrexone pharmacokinetics, Oxidoreductases antagonists & inhibitors, Oxycodone, Reproducibility of Results, Substrate Specificity, Testosterone pharmacology, Vitamin K pharmacology, Liver metabolism, Naltrexone analogs & derivatives, Naltrexone metabolism
- Abstract
Aims: To determine the kinetics of the formation of 6beta-naltrexol from naltrexone in human liver cytosol, and to investigate the role of potential inhibitors., Methods: The kinetics of the formation of 6 beta-naltrexol from naltrexone were examined in eight human liver cytosol preparations using h.p.l.c. to quantify 6 beta-naltrexol and, the extent of inhibition of 6 beta-naltrexol formation was determined using chemical inhibitors. The formation of 6 beta-naltrexol and the back reaction of 6 beta-naltrexol to naltrexone were also examined in a microsomal preparation., Results: The Vmax, Km and CLint values for the formation of 6 beta-naltrexol from naltrexone were in the ranges of 16-45 nmol mg-1 protein h-1, 17-53 microM and 0.3-2.2 ml h-1 mg-1 protein, respectively. The steroid hormones testosterone (Ki = 0.3 +/- 0.1 microM) and dihydrotestosterone (Ki = 0.7 +/- 0.4 microM) were the most potent competitive inhibitors of 6 beta-naltrexol formation, with naloxone, menadione and corticosterone also producing > 50% inhibition at a concentration of 100 microM. The opioid agonists morphine, oxycodone, oxymorphone and hydromorphone, and a range of benzodiazepines showed < 20% inhibition at 100 microM. In the microsomal preparation, there was no formation of naltrexone from 6beta-naltrexol nor any formation of 6beta-naltrexol from naltrexone., Conclusions: The intersubject variability in the kinetic parameters of 6beta-naltrexol formation could play a role in the efficacy of and patient compliance with naltrexone treatment. This variability could be due in part to a genetic polymorphism of the dihydrodiol dehydrogenase DD4, one of the enzymes reported to be responsible for the formation of 6beta-naltrexol from naltrexone. DD4 also has hydroxysteroid dehydrogenase activity which could account for the potent inhibition by the steroid hormones testosterone and dihydrotestosterone. The clinical significance of the latter finding remains to be established.
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- 2000
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17. Ribosomal proteins S5 and L6: high-resolution crystal structures and roles in protein synthesis and antibiotic resistance.
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Davies C, Bussiere DE, Golden BL, Porter SJ, Ramakrishnan V, and White SW
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- Amino Acid Sequence, Bacterial Proteins biosynthesis, Bacterial Proteins genetics, Crystallography, X-Ray, Escherichia coli genetics, Molecular Sequence Data, Protein Biosynthesis, Protein Conformation, Structure-Activity Relationship, Drug Resistance, Microbial, Escherichia coli metabolism, Ribosomal Proteins chemistry, Ribosomal Proteins metabolism
- Abstract
Antibiotic resistance is rapidly becoming a major medical problem. Many antibiotics are directed against bacterial ribosomes, and mutations within both the RNA and protein components can render them ineffective. It is well known that the majority of these antibiotics act by binding to the ribosomal RNA, and it is of interest to understand how mutations in the ribosomal proteins can produce resistance. Translational accuracy is one important target of antibiotics, and a number of ribosomal protein mutations in Escherichia coli are known to modulate the proofreading mechanism of the ribosome. Here we describe the high-resolution structures of two such ribosomal proteins and characterize these mutations. The S5 protein, from the small ribosomal unit, is associated with two types of mutations: those that reduce translational fidelity and others that produce resistance to the antibiotic spectinomycin. The L6 protein, from the large subunit, has mutations that cause resistance to several aminoglycoside antibiotics, notably gentamicin. In both proteins, the mutations occur within their putative RNA-binding sites. The L6 mutations are particularly drastic because they result in large deletions of an RNA-binding region. These results support the hypothesis that the mutations create local distortions of the catalytic RNA component.When combined with a variety of structural and biochemical data, these mutations also become important probes of the architecture and function of the translational machinery. We propose that the C-terminal half of S5, which contains the accuracy mutations, organizes RNA structures associated with the decoding region, and the N-terminal half, which contains the spectinomycin-resistance mutations, directly interacts with an RNA helix that binds this antibiotic. As regards L6, we suggest that the mutations indirectly affect proofreading by locally distorting the EF-Tu.GTP.aminoacyl tRNA binding site on the large subunit., (Copyright 1998 Academic Press Limited.)
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- 1998
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18. The activation domain of the MotA transcription factor from bacteriophage T4.
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Finnin MS, Cicero MP, Davies C, Porter SJ, White SW, and Kreuzer KN
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- Amino Acid Sequence, Bacteriophage T4 genetics, Crystallography, X-Ray, DNA metabolism, DNA-Binding Proteins genetics, DNA-Binding Proteins metabolism, Dimerization, Magnetic Resonance Spectroscopy, Models, Molecular, Molecular Sequence Data, Mutation, Protein Folding, Protein Structure, Secondary, Transcription Factors genetics, Transcription Factors metabolism, Viral Proteins genetics, Viral Proteins metabolism, Bacteriophage T4 chemistry, DNA-Binding Proteins chemistry, Transcription Factors chemistry, Transcriptional Activation, Viral Proteins chemistry
- Abstract
Bacteriophage T4 encodes a transcription factor, MotA, that binds to the -30 region of middle-mode promoters and activates transcription by host RNA polymerase. We have solved the structure of the MotA activation domain to 2.2 A by X-ray crystallography, and have also determined its secondary structure by NMR. An area on the surface of the protein has a distinctive patch that is populated with acidic and hydrophobic residues. Mutations within this patch cause a defective T4 growth phenotype, arguing that the patch is important for MotA function. One of the mutant MotA activation domains was purified and analyzed by NMR, and the spectra clearly show that the domain is properly folded. The mutant full-length protein appears to bind DNA normally but is deficient in transcriptional activation. We conclude that the acidic/hydrophobic surface patch is specifically involved in transcriptional activation, which is reminiscent of eukaryotic acidic activation domains.
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- 1997
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19. The use of massage for neonates requiring special care.
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Porter SJ
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- Humans, Infant, Newborn, Holistic Nursing methods, Massage methods, Massage nursing, Neonatal Nursing methods
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- 1996
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20. Vortex channeling along twin planes in YBa2Cu3O7-x.
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Oussena M, de Groot PA, Porter SJ, Gagnon R, and Taillefer L
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- 1995
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21. Inelastic exchange scattering in electron-energy-loss spectroscopy: Localized excitations in transition-metal and rare-earth systems.
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Porter SJ, Matthew JA, and Leggott RJ
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- 1994
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22. Crystal structure of prokaryotic ribosomal protein L9: a bi-lobed RNA-binding protein.
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Hoffman DW, Davies C, Gerchman SE, Kycia JH, Porter SJ, White SW, and Ramakrishnan V
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- Amino Acid Sequence, Crystallography, X-Ray, Geobacillus stearothermophilus, Models, Molecular, Molecular Sequence Data, Protein Conformation, RNA-Binding Proteins chemistry, Ribosomal Proteins chemistry
- Abstract
The crystal structure of protein L9 from the Bacillus stearothermophilus ribosome has been determined at 2.8 A resolution using X-ray diffraction methods. This primary RNA-binding protein has a highly elongated and unusual structure consisting of two separated domains joined by a long exposed alpha-helix. Conserved, positively charged and aromatic amino acids on the surfaces of both domains probably represent the sites of specific interactions with 23S rRNA. Comparisons with other prokaryotic L9 sequences show that while the length of the connecting alpha-helix is invariant, the sequence within the exposed central region is not conserved. This suggests that the alpha-helix has an architectural role and serves to fix the relative separation and orientation of the N- and C-terminal domains within the ribosome. The N-terminal domain has structural homology to the smaller ribosomal proteins L7/L12 and L30, and the eukaryotic RNA recognition motif (RRM).
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- 1994
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23. The MotA protein from bacteriophage T4 contains two domains. Preliminary structural analysis by X-ray diffraction and nuclear magnetic resonance.
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Finnin MS, Hoffman DW, Kreuzer KN, Porter SJ, Schmidt RP, and White SW
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- Base Sequence, Crystallography, DNA Replication, Magnetic Resonance Spectroscopy, Molecular Sequence Data, Peptide Fragments chemistry, Regulatory Sequences, Nucleic Acid, X-Ray Diffraction, Bacteriophage T4 chemistry, DNA-Binding Proteins ultrastructure, Transcription Factors ultrastructure, Viral Proteins ultrastructure
- Abstract
Controlled protease cleavage experiments and N-terminal sequence analyses were used to show that the transcriptional activator MotA from bacteriophage T4 has a two-domain structure. The N and C-terminal domains have M(r) values of 10,300 and 11,800, respectively, and were separately cloned and overexpressed in Escherichia coli. One and two-dimensional NMR spectroscopy indicate that both domains have stably folded structures and contain extensive secondary structure. The N-terminal domain is substantially alpha-helical, whereas the C-terminal domain has a high content of beta-strand. The N-terminal domain has been crystallized under three different conditions, all with the space group P3(1(2))21 and similar unit cell dimensions. The best crystals are grown from ammonium sulfate, have cell dimensions a = b = 46.7 A, c = 139.6 A, and diffract to beyond 2.4 A. The high quality of the NMR and diffraction data will allow a complete structural analysis of MotA by a combination of these techniques.
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- 1993
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24. Effects of oophorectomy on biochemical and bone variables in the rat.
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Morris HA, Porter SJ, Durbridge TC, Moore RJ, Need AG, and Nordin BE
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- Alkaline Phosphatase blood, Analysis of Variance, Animals, Biomarkers, Bone and Bones anatomy & histology, Calcium metabolism, Female, Hydroxyproline urine, Osteocalcin blood, Phosphates blood, Rats, Rats, Inbred Strains, Serum Albumin analysis, Bone and Bones metabolism, Ovariectomy
- Abstract
The metabolic effects of oophorectomy (Oophx) were studied in 6-month-old rats maintained on a normal chow diet. Nine weeks following operation, Oophx animals had a significantly lower femoral trabecular bone volume (BV/TV) than sham-operated animals; mean (SD) Oophx 8.5 (3.8)%; Sham 13.4 (2.5)%; P = 0.013). They also had a higher urine hydroxyproline (P less than 0.001), serum alkaline phosphatase activity (P less than 0.001), serum phosphate (P less than 0.001) and lower serum albumin (P less than 0.001) than the controls. Serum osteocalcin was inversely related to the BV/TV in the Oophx animals at 9 weeks post operation (r = -0.85, P = 0.007, n = 8). A fall in serum ionized calcium from 3 to 9 weeks post operation correlated with a fall in urinary hydroxyproline in the Oophx animals (r = 0.57, P = 0.002, n = 27). The data are consistent with a model of ovarian hormones acting directly to modulate bone cell activity as well as exerting an effect on the renal handling of phosphate.
- Published
- 1992
- Full Text
- View/download PDF
25. Comparison of Duroc and British landrace pigs for meat a and eating quality.
- Author
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Cameron ND, Warriss PD, Porter SJ, and Enser MB
- Abstract
Duroc and halothane negative British Landrace boars and gilts were performance tested from 30 to 80kg on ad-libitum or restricted feeding regimes, with like-sexed non-littermate groups of pigs penned together. Meat and eating quality was determined using objective laboratory measurements and by taste panel and consumer panel assessment on 160 pigs with 20 full-sib families for each breed, and two boars and two gilts per family. Duroc M. longissimus(†) was darker in colour, had a more intense, redder colour and contained more fat and less moisture than Landrace muscle. Duroc subcutaneous fat was less firm, had a higher water content and concentrations of linoleic acid and lower concentrations of stearic acid than Landrace fat. The taste and consumer panels scored Duroc meat as being more juicy, but less tender, having poorer flavour and being less acceptable than Landrace meat. The higher juiciness scores of Duroc meat were probably attributable to the higher intramuscular fat content compared to Landrace meat. Duroc boars had lower values for flavour liking and acceptability compared to other breed-sex combinations which may be due to the particular fatty acid composition of the subcutaneous fat in Duroc boars., (Copyright © 1990. Published by Elsevier Ltd.)
- Published
- 1990
- Full Text
- View/download PDF
26. Distribution of a major allergen of rye grass (Lolium perenne) pollen between other grass species.
- Author
-
Standring R, Spackman V, and Porter SJ
- Subjects
- Allergens immunology, Animals, Antibodies immunology, Antibodies, Monoclonal isolation & purification, Antibody Specificity, Collodion, Cross Reactions, Electrophoresis, Polyacrylamide Gel methods, Humans, Paper, Plant Extracts analysis, Plant Extracts immunology, Poaceae analysis, Protein Binding, Rabbits, Allergens analysis, Epitopes analysis, Lolium immunology, Poaceae immunology
- Abstract
Polyacrylamide gel electrophoresis in sodium dodecyl sulphate (SDS) followed by protein staining has shown that extracts from 11 different grass pollens contained proteins with similar molecular weights to that of the allergen R7 from rye grass (Lolium perenne) pollen extract (i.e. 29,000-31,000 daltons). Western blotting and detection with polyclonal (rabbit) antibodies raised against the purified R7 (Rye I) allergen indicated that these proteins were antigenically related and their allergenic properties were demonstrated by the binding of human IgE to immunoblots. The distribution of cross-reacting antigenic determinants was further investigated by immunoblotting with 2 mouse monoclonal antibodies, R7M1 and R7M2, produced with purified R7 as the initial immunogen. The 2 monoclonal antibodies were shown to react with 'R7-like' components of grass pollen extracts other than the component from rye grass. Differences in the distribution of R7M1 and R7M2 binding were found indicating that they are directed at separate R7 epitopes.
- Published
- 1987
- Full Text
- View/download PDF
27. The metabolic response of tumour-bearing mice to fasting.
- Author
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Rofe AM, Porter SJ, Bais R, and Conyers RA
- Subjects
- 3-Hydroxybutyric Acid, Acetoacetates metabolism, Adipose Tissue metabolism, Animals, Blood Glucose metabolism, Glucose metabolism, Hydroxybutyrates metabolism, Ketone Bodies metabolism, Lactates metabolism, Liver metabolism, Liver Glycogen metabolism, Male, Melanoma blood, Mice, Mice, Inbred C57BL, Pyruvates metabolism, Fasting, Melanoma metabolism
- Abstract
The suggestion that the ketonaemic response to fasting may be altered in the tumour-bearing state was investigated by studying the metabolism of fasted C57/BL6j mice bearing transplanted B16 melanomas. Ketone body (D-3-hydroxybutyrate and acetoacetate) concentrations in the blood of the tumour-bearing mice were significantly increased after a 24 h fast compared to control mice with identical dietary histories. Hepatic glycogen levels were lower at the start of the fasting period in the tumour-bearing mice as were the fat stores. The loss of adipose tissue during the fasting period was greater in the tumour-bearing mice. After 48 h of fasting, the ketonaemia was significantly lower in the tumour-bearing mice compared to the appropriate controls. Two distinct metabolic states are indicated in these fasted tumour-bearing mice, one characterised by accelerated ketonaemia, and a later, near terminal stage, where fat deposits are markedly depleted and ketonaemia is decreased.
- Published
- 1985
- Full Text
- View/download PDF
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