12 results on '"L. Pawlak"'
Search Results
2. G550(P) What matters to families of children with complex medical needs? Co-designing an information leaflet for children with complex medical needs
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L Pawlak, S Neilson, R Sheeley, C Wicks, R Ramachandran, T Gray, S Roberts, and Joy Gough
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Medical education ,business.industry ,media_common.quotation_subject ,Context (language use) ,Focus group ,Instinct ,Multidisciplinary approach ,Anticipation (artificial intelligence) ,Food choice ,Medicine ,business ,Psychosocial ,Hindsight bias ,media_common - Abstract
Aim To improve communication between healthcare professionals and families/carers of children with complex medical needs, we co-designeda patient information booklet, to be given on admission to our ward. Methods A focus group involving six families of children with medically complex needs was held with the aid of our Patient Engagement lead. Four questions were asked: In hindsight, what information do you wish you had known or been given on admission to hospital or following diagnosis? What information could we give you that would make your lives easier? What advice would you give other parents in a similar situation? What other resources or contacts have helped you? The resulting information informed the creation of a patient information booklet. Results The work highlighted the importance of seeking patient input, whilst our anticipation had been a focus on medical information, their desire was for much more practical information related to their wider context. Reflecting their longer stay; knowledge of accommodation, food choices and parking were key with one family highlighting they had spent £1000 on parking. In keeping with literature reporting on the high psychosocial and financial burden on these families, information on how to get financial support and signposting to charities that aided with this were valued. Interestingly families had mixed feelings about parent run support groups. Results also made us question common ward practices with parents talking of the emotional distress caused by repeatedly recounting their child’s, often difficult, medical journey. Many found being part of multidisciplinary meetings overwhelming and wanted greater choice over how they were involved. They wanted the important role of allied health professionals to be clearer from the start. Stories also illustrated how misleading commonly used medical phrases such as ‘Delayed development’ can be. Amongst the advice they would give to families they commented on the importance of not losing hope and trusting your own parental instinct; as a result families’ own stories and words of advice have been included in the information leaflet. Conclusion The involvement of families is vital in co-designing any information given to families of children with complex medical needs. more...
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- 2020
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Catalog
3. Effect of Viscosity on Solvent-Free Extrusion Emulsification: Molecular Structure
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Michael Thompson, A. Goger, David J.W. Lawton, John L. Pawlak, Alex Klymachyov, and Mark A. Arnould
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Materials science ,Chromatography ,General Chemical Engineering ,Relative viscosity ,Rheometer ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Industrial and Manufacturing Engineering ,Viscosity ,020401 chemical engineering ,Chemical engineering ,Extrusion ,Particle size ,0204 chemical engineering ,Reduced viscosity ,0210 nano-technology ,Dispersion (chemistry) ,Phase inversion - Abstract
A new continuous emulsification technique known as solvent-free extrusion emulsification (SFEE) was recently introduced to prepare submicron particles (100–500 nm) from high viscosity polymers (100–1000 Pa·s) with a twin screw extruder. The present study examined the influence of matrix viscosity on its dispersion mechanism using cross-linked polyester as a viscosity modifier. The investigation used an inline rheometer for transient and steady state viscosity measurements, and offline characterizations including Soxhlet extraction, colorimetric titration, and particle size analysis. Though it remained possible to produce particles close to their target size of 100–200 nm, particle size was notably increased by varying the matrix viscosity from 250 Pa·s for the neat polyester up to 630 Pa·s with the added modifier. The results point to thicker striated lamellae from less effective mixing prior to phase inversion when the matrix viscosity was increased without a corresponding increase in surface active spec... more...
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- 2017
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4. Inline rheological behavior of dispersed water in a polyester matrix with a twin screw extruder
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John L. Pawlak, A. Goger, Mark A. Arnould, Alexander N. Klymachyov, Michael Thompson, David J.W. Lawton, and Robin L. Sheppard
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chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,Viscometer ,02 engineering and technology ,General Chemistry ,Polymer ,021001 nanoscience & nanotechnology ,Polyester ,Viscosity ,020401 chemical engineering ,Rheology ,chemistry ,Materials Chemistry ,Extrusion ,0204 chemical engineering ,Composite material ,0210 nano-technology ,Dispersion (chemistry) ,Phase inversion - Abstract
Solvent-free extrusion emulsification (SFEE) is a complex process using twin-screw extrusion to prepare solid-liquid dispersions of high viscosity polymers and has received little study to date on its inherent mechanisms. To gain rheological insights into the earliest stage of SFEE as the interfacial boundary between water and polymer grows, prior to phase inversion, an inline orifice-plate type viscometer is introduced to monitor transient behavior over a wide range of viscosities. The presented work examines rheological changes of a polyester-water system produced by varying two factors thought to significantly control the final state of the dispersion, specifically polar group contributions to surface energy and viscosity. A processing modifier was combined with the polyester to study the influence of these two factors. The inline viscometer revealed an abrupt transition in viscosity occurred with the developed state of water dispersion, confirming observations of a prior batch study. Analysis of the rheological response indicated that a higher polar surface energy contribution had the greatest influence on the state of this transition, and that a steeper transition was related to greater incorporation of water within the polyester matrix. POLYM. ENG. SCI., 2017. © 2017 Society of Plastics Engineers more...
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- 2017
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5. Influence of anionic and non-ionic surfactants on nanoparticle synthesis by solvent-free extrusion emulsification
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Tomislav Ivancic, David J.W. Lawton, Michael Thompson, and John L. Pawlak
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chemistry.chemical_classification ,Molar concentration ,Chemistry ,02 engineering and technology ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Polyester ,Colloid and Surface Chemistry ,Pulmonary surfactant ,Chemical engineering ,Phase (matter) ,Emulsion ,Extrusion ,0210 nano-technology ,Dispersion (chemistry) - Abstract
This study examines the impact of surfactants on the mechanism of a new solvent-free extrusion emulsification (SFEE) technique. Two sets of surfactants were used in this work, three anionic (SDBS, Unicid 350, Calfax DB-45) and three non-ionic (Igepal CO-890, Brij 58, Synperonic F-108). Of the anionic surfactants, only SDBS and Calfax were found to create stable O/W emulsions with a polyester in the desired 100–200 nm size range; the latter requiring a lower molar concentration. Igepal CO-890 and Brij 58 resulted in only partial emulsification despite requiring higher molar loadings than their anionic counterparts to accomplish this outcome, with majority of the polymer leaving the extruder without phase inverting. The study reinforced previous findings that the dispersion stage (zone) controls the SFEE technique, and highlighted the importance of water affinity displayed by a surfactant species to compensate for high retarding viscous force for mixing water into the polymer melt. more...
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- 2020
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6. A Structural Model for the Iron-Nitrosyl Adduct of Gentisate Dioxygenase
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William W. Brennessel, Amy L. Speelman, Nicolai Lehnert, Corey J. White, Piotr L. Pawlak, Ferman A. Chavez, Atanu Banerjee, and Jia Li
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010405 organic chemistry ,Hydrogen bond ,Chemistry ,010402 general chemistry ,01 natural sciences ,Article ,0104 chemical sciences ,Adduct ,law.invention ,Inorganic Chemistry ,Solvent ,Crystallography ,chemistry.chemical_compound ,law ,Molecular vibration ,X-ray crystallography ,Density functional theory ,Electron paramagnetic resonance ,Phosphine - Abstract
We present the synthesis, properties, and characterization of [Fe(T1Et4iPrIP)(NO)(H(2)O)(2)](OTf)(2) (1) (T1Et4iPrIP = Tris(1-ethyl-4-isopropyl-imidazolyl)phosphine) as a model for the nitrosyl adduct of gentisate 1,2-dioxygenase (GDO). The further characterization of [Fe(T1Et4iPrIP)(THF)(NO)(OTf)](OTf) (2) which was previously communicated (Inorg. Chem. 2014, 53, 5414) is also presented. The weighted average Fe-N-O angle of 162° for 1 is very close to linear (≥ 165°) for these types of complexes. The coordinated water ligands participate in hydrogen bonding interactions. The spectral properties (EPR, UV-vis, FTIR) for 1 are compared with 2 and found to be quite comparable. Complex 1 closely follows the relationship between the Fe−N−O angle and NO vibrational frequency which was previously identified for 6-coordinate {FeNO}(7) complexes. Liquid FTIR studies on 2 indicate that the ν(NO) vibration position is sensitive to solvent shifting to lower energy (relative to the solid) in donor solvent THF and shifting to higher energy in dichloromethane. The basis for this behavior is discussed. The K(eq) for NO binding in 2 was calculated in THF and found to be 470 M(−1). Density functional theory (DFT) studies on 1 indicate donation of electron density to the iron center from the π* orbitals of formally NO(−). Such a donation accounts for the near linearity of the Fe−N−O bond and the large ν(NO) value of 1791 cm(−1). more...
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- 2018
7. Effect of Viscosity on Solvent-Free Extrusion Emulsification: Varying System Temperature
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A. Goger, Michael Thompson, David J.W. Lawton, John L. Pawlak, Mark A. Arnould, and Chemical Engineering
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chemistry.chemical_classification ,Materials science ,Rheometry ,General Chemical Engineering ,Rheometer ,Plastics extrusion ,Mixing (process engineering) ,02 engineering and technology ,General Chemistry ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,Viscosity ,chemistry ,Chemical engineering ,Extrusion ,Particle size ,0210 nano-technology - Abstract
Solvent-free extrusion emulsification (SFEE) is a new continuous approach for producing nanoparticles from high viscosity molten polymers using a twin-screw extruder. In a previous study, the influence of melt viscosity on lamellae development in the phase inversion mechanism was investigated for an otherwise fixed system of variables including temperature, mixing intensity and surfactant content. Varying system temperature in the current study to produce the same melt viscosities as those previously examined, did not produce the same linear effect on particle size. The investigation to understand the influence of system temperature on the SFEE mechanism was done by using an inline rheometer and different screw/barrel configurations to simulate different zones of SFEE. Characterizations of the emulsified polyester included colorimetric titrations, particle size analysis, parallel plate rheometry, and gel permeation chromatography (GPC). Raising system temperature has a negative effect on the mechanism for producing smaller particles, countering the positively affected parameters, namely lower melt viscosity and a higher content of surface active species based on a contributing neutralization reaction. The findings show good fit to published studies of an osmotic pressure driven emulsification mechanism, which is beneficial in clarifying the role of surfactants in the process. Overall, the results show system temperature to be a complex variable in SFEE, deeming it undesirable in optimizing the process. NSERC more...
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- 2018
8. In Situ Rheological Measurement of an Aqueous Polyester Dispersion during Emulsification
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David J.W. Lawton, John L. Pawlak, Michael Thompson, and A. Goger
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chemistry.chemical_classification ,Chromatography ,Aqueous solution ,Materials science ,General Chemical Engineering ,Rheometer ,Mixing (process engineering) ,General Chemistry ,Polymer ,Industrial and Manufacturing Engineering ,Polyester ,Impeller ,chemistry ,Rheology ,Composite material ,Dispersion (chemistry) - Abstract
Rheological analysis of a complex fluid system like an aqueous polymer dispersion can be challenging but can reveal mechanistic information as the viscous melt is emulsified. A pressurized vessel was used as a rheometer, based on the Metzner–Otto approach, to evaluate formulation variables where the developed morphology of a polyester/water mixture was shear-dependent. The parameters of the study were resin-to-water ratio (R/W), surfactant (type and concentration), and process variables of impeller speed and temperature. Transient in situ information on the system during the mixing of water into the molten polymer showed that a rapid, near-instantaneous decrease in the torque on the impeller occurred consistently around 2% water addition, related to the onset of the developed morphological state. It was observed to only demonstrate a drop in the torque for high shear rates and only with the appropriate content of surface-active species, revealing the chemical and physical parameters necessary to emulsify ... more...
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- 2015
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9. Oxalate Oxidase Model Studies – Substrate Reactivity
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Manashi Panda, Derek J. Averill, Jia Li, Brian J. Shay, Borislava Nikolovski, Piotr L. Pawlak, Ferman A. Chavez, Atanu Banerjee, and William W. Brennessel
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Inorganic Chemistry ,chemistry.chemical_compound ,Oxalate oxidase ,Chemistry ,Coordination polymer ,Ligand ,Inorganic chemistry ,Polymer chemistry ,Substrate (chemistry) ,Carboxylate ,Acetonitrile ,Dissolution ,Oxalate - Abstract
The synthesis and structure of [MnLCl]0.5H2O (1·0.5H2O, HL = 1-benzyl-4-acetato-1,4,7-triazacyclononane) is reported. Complex 1 exists as a coordination polymer in the solid state, and the MnII center is bonded to three amine nitrogen atoms, one carboxylate oxygen atom, a chlorido ligand, and an adjacent carboxylate group in a chelating fashion to afford a seven-coordinate center. The dissolution of 1 in acetonitrile containing excess oxalate (ox) ions results in a monomeric species. When mixtures of 1 and oxalate ions are exposed to oxygen under ambient conditions, a dark pink EPR-silent species is generated. The pink species is believed to be [MnIII(ox)2]–, which results from the displacement of the ligand L– by an oxalate ion. The decomposition of this species ultimately results in the formation of 1 equiv. of CO2 per oxalate ion consumed, a HCO3– ion, and a MnII species. Further reaction of the resulting MnII species with excess oxalate in the presence of oxygen leads to additional oxalate degradation. more...
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- 2015
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10. In Situ Rheological Measurement of an Aqueous PolyesterDispersion during Emulsification.
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A. Goger, M. R. Thompson, J. L. Pawlak, and D. J.W. Lawton
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- 2015
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11. Relationship between Sleep Bruxism, Perceived Stress, and Coping Strategies.
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Saczuk K, Lapinska B, Wilmont P, Pawlak L, and Lukomska-Szymanska M
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- Adult, Aged, Case-Control Studies, Female, Humans, Male, Middle Aged, Sleep, Sleep Bruxism etiology, Young Adult, Adaptation, Psychological, Sleep Bruxism psychology, Stress, Psychological complications
- Abstract
Sleep bruxism (SB) is a common phenomenon defined as a masticatory muscle activity during sleep. Untreated severe SB can have significant dental and orofacial consequences. SB has often been linked with stress and maladaptive coping strategies. Therefore, in this study, a potential correlation between SB, perceived stress and coping strategies was evaluated. A total of 60 adults were enrolled into this study. Participants underwent a detailed intra- and extraoral exam focused on detecting bruxism symptoms. Additionally, the overnight Bruxism Index was recorded using the Bruxoff device. A total of 35 participants with symptoms of bruxism were assigned to the study group, whereas 25 asymptomatic participants were assigned to the control group. The Perceived Stress Scale (PSS-10) was used for stress assessment and Brief-COPE for coping strategies. Results showed that the higher the PSS-10 score, the higher the Bruxism Index was in the study group. Positive coping strategies were chosen most frequently in the control group, while maladaptive ones were chosen in the study group. It can be concluded that there is a relationship between perceived stress and sleep bruxism. Moreover, the type of coping strategies used by participants may have an impact on sleep bruxism, but the relationship should be further investigated. more...
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- 2019
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12. The Bruxoff Device as a Screening Method for Sleep Bruxism in Dental Practice.
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Saczuk K, Lapinska B, Wilmont P, Pawlak L, and Lukomska-Szymanska M
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Sleep bruxism (SB) is a masticatory muscle activity during sleep and a common phenomenon. Severe SB can have a serious impact on the success of dental treatment. Reliable methods of screening and diagnosing patients with SB are crucial. Therefore, in this study, a Bruxoff device as a potential screening and diagnostic method for sleep bruxism was evaluated. A total of 60 adults participated in this study: 35 patients with symptoms of bruxism (study group) and 25 asymptomatic patients (control group). Data were recorded using Bruxoff. All symptomatic patients participating in the study turned out to be bruxers, while not all asymptomatic patients turned out to be non-bruxers according to the Bruxoff device. Bruxoff is a simple screening device that can be safely used to evaluate masseter muscle activity during sleep. Since the device does not have a built-in microphone and/or video camera and, therefore, cannot record grinding sounds, the objective capabilities of Bruxoff as a single diagnostic device for sleep bruxism are limited. more...
- Published
- 2019
- Full Text
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