bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of linear aliphatic polycarbonate macroglycols using dimethylcarbonate
Authors: Foy Ernest , Farrell Joseph B. , Higginbotham Clement L. 
Published: October 2008

AbstractA series of linear aliphatic polycarbonate polyols were synthesized using dimethylcarbonate and a linear alkane diol or specific combinations of linear alkane diols. Polyol synthesis was carried out in a two‐stage process using dimethylcarbonate and a linear alkane diol to prepare a series of homopolymer polycarbonate polyols. Polyol grades were characterized using Fourier transform infrared spectroscopy, gel permeation chromatography, and differential scanning calorimetery techniques. Suitable reaction conditions were developed to yield polycarbonate polyols of number average molecular weight between 700 and 1700. The crystallinity of the polycarbonate polyols was shown to reduce as the molecular weight of the alkane diols used in the polycarbonate synthesis was increased. These polymers offer the potential for use in the synthesis of ether free polyurethane elastomers for biomedical applications. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Post‐oligomerization of α‐olefin oligomers: A route to single‐component and multicomponent synthetic lubricating oils
Authors: Kissin Yury V. , Schwab Frederick C. 
Published: October 2008

AbstractThis article describes a synthetic route to single‐component and multicomponent base stocks for synthetic lubricated oils. The synthesis was carried out in two stages. First, oligomers of α‐olefins (1‐hexene, 4‐methyl‐1‐pentene, and 1‐decene) were prepared via reactions catalyzed by metallocene catalysts. The distribution of the oligomers with respect to their oligomerization number could be controlled by the reaction temperature. The oligomer mixtures were then fractionated, and the lightest components, dimers and trimers, were separated. Finally, the latter materials, branched α‐olefins containing vinylidene double bonds, were further oligomerized with cationic catalysts. One such material prepared in the two‐stage process, the dimer of the 1‐decene dimer (C40 product), has a kinematic viscosity of 6.4 cs at 100°C and a viscosity index of 147. It represents the first example of a single‐component base stock for synthetic lubricating oils. The post‐oligomerization procedure was performed on unfractionated oligomer mixtures as well, leading to an improved distribution of the final materials with respect to the carbon atom number. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Poly(vinyl alcohol)/chitosan oligosaccharide blend submicrometer fibers prepared from aqueous solutions by the electrospinning method
Authors: Lee Hyun Woo , Karim Mohammad Rezaul , Park Jae Hyeung , Ghim Han Do , Choi Jin Hyun , Kim Ketack , Deng Yulin , Yeum Jeong Hyun 
Published: October 2008

AbstractSubmicrometer fibers of poly(vinyl alcohol) (PVA) and chitosan oligosaccharide [COS; i.e., (1→4)‐2‐amino‐2‐deoxy‐β‐D‐glucose] were prepared by an electrospinning method with aqueous solutions with polymer concentrations of 7.5–15 wt %. Scanning electron microscopy, Fourier transform infrared, X‐ray diffraction, differential scanning calorimetry, and thermogravimetric analysis were used to characterize the morphology and properties of the PVA/COS fibers. The PVA/COS mass ratio, the total polymer concentration, and processing parameters such as the applied voltage and capillary‐to‐collector distance played important roles in controlling the fiber morphology. Fourier transform infrared and X‐ray diffraction data demonstrated that there were possibly hydrogen bonds between COS and PVA molecules that weakened the interactions in COS and improved the electrospinnability of PVA/COS. Moreover, with a higher percentage of COS in the PVA/COS blend fibers, superior thermal stability could be obtained. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Anhydride production as an additional mechanism of poly(3‐hydroxybutyrate) pyrolysis
Authors: Ariffin Hidayah , Nishida Haruo , Shirai Yoshihito , Hassan Mohd Ali 
Published: October 2008

AbstractAnhydrides production is newly proposed as an additional pyrolysis mechanism of a biopolymer, poly(3‐hydroxybutyrate) (PHB). In spite of many suggestions of multiple degradation mechanisms, simple random chain scission by β‐elimination has been accepted as an exclusive mechanism of the thermal degradation of PHB. However, a wide range of activation energy value of the degradation and the deviation from the random chain scission statistics have suggested the presence of other kinds of mechanism out of the random scission. To confirm other mechanisms out of the random scission, minor pyrolyzates from PHB were characterized with 1H/13C‐NMR, Fourier transform infrared spectroscopy, and fast atom bombardment mass spectrometry. As a result, crotonic anhydride and its oligomers were detected as minor products from condensation reactions between carboxyl groups. The anhydrides production must be one reaction out of the conforming process to the random degradation statistics and contribute to the complexity of PHB pyrolysis. An expected thermal degradation pathway of PHB was proposed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Flame‐retardant epoxy resin from a caged bicyclic phosphate quadridentate silicon complex
Authors: Zhang Li‐Li , Liu An‐Hua , Zeng Xing‐Rong 
Published: October 2008

AbstractThe synergistic effects of phosphorus–silicon in a caged bicyclic phosphate quadridentate silicon complex (CPQS) on the flame retardancy of epoxy resin (EP) were studied with the limiting oxygen index, the UL‐94 test, thermogravimetric analysis, real time Fourier transform infrared spectroscopy, X‐ray powder diffraction, and scanning electron microscopy. The limiting oxygen index data, UL‐94 test, and thermogravimetric analysis results showed that the use of phosphorus and silicon together had a synergistic effect on the flame retardancy of EP. The Fourier transform infrared results and X‐ray powder diffraction measurements provided evidence that CPQS could promote the formation of char with silicophosphate and phosphocarbonaceous structures. The morphological structures observed by scanning electron microscopy demonstrated that more compact charred layers were formed in samples with CPQS than in those with 1‐oxo‐1‐phospha‐2,6,7‐trioxabicyclo[2.2.2]‐4‐hydroxymethyl octane and tetraethoxysilane. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Influence of fluorocarbon chains on the crystallization behaviors of aliphatic polyurethanes
Authors: Chen Kuo‐Yu , Kuo Jen‐Feng 
Published: October 2008

AbstractThe aliphatic polyurethanes were synthesized from either hexamethylene diisocyanate (HDI) and 2,2,3,3‐tetrafluoror‐1,4‐butanediol or HDI and 1,4‐butandiol. The crystallization behaviors of the aliphatic polyurethanes were characterized using differential scanning calorimetry, wide‐angle X‐ray diffraction, and polarized optical microscopy. The effects of fluorocarbon chains on the solubility behavior, microstructure, thermal transition property, crystal morphology, and crystallization behaviors were investigated. The fluorinated polyurethane exhibited a lower viscosity, higher solubility in organic solvents, smaller fraction of ordered hydrogen‐bonded carbonyls, and lower transition temperatures than the corresponding fluorine‐free polyurethane. The wide‐angle X‐ray diffraction measurements reflected change of crystal structure with the (CF2)2 moieties in place of (CH2)2 moieties. Polarized optical microscopy also revealed that the polyurethanes exhibited a variety of spherulitic texture. The isothermal crystallization process of the polyurethanes was described by the Avrami analysis. The result showed that the Avrami exponent (n) was around 2.5, which suggested the growth of crystal might be spherulite growth corresponding to homogeneous (thermal) nucleation and diffusion control. The crystallization activation energy was estimated to be −130.9 kJ/mol for the fluorinated polyurethane and −276.9 kJ/mol for the fluorine‐free polyurethane from Arrhenius form. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Poly(3‐dodecyl thiophene)—Organically modified montmorillonite clay nanocomposites: Influence of chain regioregularity and preparation condition on physical, mechanical, optical, and conductivity properties
Authors: Kuila Biplab K. , Nandi Arun K. 
Published: October 2008

AbstractThe properties of regioregular(R) (98.5 mol % H‐T) and regioirregular(I) (80.5 mol % H‐T) poly(3‐dodecyl thiophene)(P3DDT)—organically modified montmorillonite (om‐MMT) clay nanocomposites obtained from solvent‐cast and melt‐cooled procedures are compared. The solvent‐cast P3DDTI nanocomposites showed partially exfoliated clay structure but P3DDTR nanocomposites showed multistack exfoliation. Type 1 crystalline polymorph was produced in solvent‐cast systems whereas melt‐cooled P3DDTI samples showed mesomorphic structure. Storage modulus of P3DDTI nanocomposites increased with clay concentration showing a maximum increase of 255%. The UV‐vis spectra showed blue shift of π–π* transition band and photoluminescence spectra indicated seven times increase of normalized intensity in solvent cast P3DDTI composites. DC conductivity and I–V characteristic curves showed increased insulating properties with om‐clay concentration. The physical, mechanical, and optical properties of P3DDTI nanocomposites are more improved than that of P3DDTR nanocomposites and from their pristine polymers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Simple modifications to the NMR PGSE technique for investigations in the regime of short diffusion observation times
Authors: Anisimov A.V. , Mishagina E.A. , Dautova N.R. 
Published: October 2008

AbstractSimple modifications to the spin‐echo NMR technique with pulsed magnetic field gradients are proposed. These modifications make it possible to compensate the negative influence of gradient pulse fronts by applying an additional gradient pulse, to eliminate the acoustic effect of gradient pulses on a sample by decoupling the probe and gradient coils, and to simplify the generation of bipolar gradient pulses of the magnetic field using a scheme of two electronic circuits. © 2008 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 33B: 216–219, 2008
Actively decoupled transmit–receive coil‐pair for mouse brain MRI
Authors: Garbow Joel R. , Mcintosh Charlie , Conradi Mark S. 
Published: October 2008

AbstractA low‐cost, high‐performance RF coil‐pair for MR imaging of mouse brain is described. A surface receiving coil is used for high spin‐sensitivity, whereas a larger transmit coil, located outside the mouse holder, delivers good B1 uniformity across the brain with reasonable efficiency. The volume coil is constructed with an open architecture, making experimental setup easy and providing clear access to the head of the mouse. Each coil is switched between active and inactive modes using PIN diodes driven by a small amplifier external to the spectrometer. Because of this active decoupling, there is no requirement for orthogonal orientation of the coils. The coil pair is platform independent, requiring only a transmit/receive (T/R) signal to switch the amplifier that drives the PIN diodes and can therefore be used with virtually any commercial or home‐built MR scanner. © 2008 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 33B: 252–259, 2008
In vivo MRI‐based dental impression using an intraoral RF receiver coil
Authors: Tymofiyeva O. , Rottner K. , Gareis D. , Boldt J. , Schmid F. , Lopez M.A. , Richter E.‐J. , Jakob P.M. 
Published: October 2008

AbstractThe MRI‐based contrast‐enhanced method of tooth surface digitization provides an alternative possibility for making a dental impression. It has recently been demonstrated that tooth surface digitization with an accuracy sufficient for production of dental restorations is possible using a clinical whole‐body MRI scanner. However, for an in vivo application of the technique, the required high nominal resolution and signal‐to‐noise ratio have to be achieved within reasonable measurement times. Existing radio frequency (RF) volume and surface coils have not been able to fulfill this requirement. The objective of this work was to develop a dedicated RF receiver coil for contrast‐enhanced dental MRI which provides a high sensitivity in the region of the whole dental arch and allows for application of the contrast media into the mouth of the patient. To achieve this goal, an intraoral dental coil design with a built‐in contrast medium applicator was developed and implemented. The coil was shown to enable high‐resolution contrast‐enhanced dental MRI in vivo. This was demonstrated on four teeth prepared for dental restorations. The average accuracy obtained for all four teeth was below 100 μm. For two of the teeth, copings were modeled based on MRI data and produced from zirconium oxide using computer‐aided design and manufacturing (CAD/CAM) technology. © 2008 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 33B: 244–251, 2008
A tool for enhancement and scoring of DNA repair foci
Authors: Gerashchenko Bogdan I. , Dynlacht Joseph R. 
Published: October 2008

AbstractUpon induction of DNA double‐strand breaks (DSBs), Mre11 and Rad50 proteins of the Mre11 DNA repair complex accumulate at the sites of DSBs and form discrete nuclear foci. Precision in scoring of Mre11/Rad50‐containing foci depends upon detection of those foci, some of which have a fluorescence staining intensity that is too close to the fluorescence staining intensity of the remaining Mre11 and Rad50 proteins that have not been incorporated into foci. Human U‐1 melanoma cells in exponential growth were irradiated with various doses of X‐rays (0‐12 Gy) to induce the formation of repair foci. Four hours after irradiation, cells were simultaneously labeled for Mre11 and Rad50 proteins, using a two‐color immunofluorescence staining technique. Laser scanning confocal microscopy was used to collect the composite images of randomly selected cell nuclei. Intensity correlation analysis (ICA) of equally intense fluorescence signals from Mre11 and Rad50 proteins was performed to obtain the regions with correlated pixels. ICA permitted enhanced detection of low level fluorescence of Mre11/Rad50 foci (“hidden” foci) that can be barely detected upon imaging of only one protein. For example, while imaging of only one protein (either Mre11 or Rad50) in the nucleus of a 6 Gy‐irradiated cell revealed 9 foci, imaging of two proteins with ICA revealed 11 foci. ICA permitted an evaluation of the dose dependence of nuclear foci in cells irradiated with various doses of X‐rays, with focus formation increasing up to a dose of 6 Gy. Our data accumulated using two‐color immunofluorescence staining of Mre11 and Rad50 proteins and ICA of these two target proteins provide a basis for enhanced detection and accuracy in the scoring of DNA repair foci. © 2008 International Society for Advancement of Cytometry
The choices, choosing model of quality of life: linkages to a science base
Authors: Gurland Barry J. , Gurland Roni V. 
Published: October 2008

AbstractBackgroundA previous paper began with a critical review of current models and measures of quality of life and then proposed criteria for judging the relative merits of alternative models: preference was given to finding a model with explicit mechanisms, linkages to a science base, a means of identifying deficits amenable to rational restorative interventions, and with embedded values of the whole person. A conjectured model, based on the processes of accessing choices and choosing among them, matched the proposed criteria. The choices and choosing (c–c) process is an evolved adaptive mechanism dedicated to the pursuit of quality of life, driven by specific biological and psychological systems, and influenced also by social and environmental forces.ObjectiveIn this paper the c‐c model is examined for its potential to strengthen the science base for the field of quality of life and thus to unify many approaches to concept and measurement.ConclusionsA third paper in this set will lay out a guide to applying the c–c model in evaluating impairments of quality of life and will tie this evaluation to corresponding interventions aimed at relieving restrictions or distortions of the c–c process; thus helping people to preserve and improve their quality of life. The fourth paper will demonstrate empirical analyses of the relationship between health imposed restrictions of options for living and conventional indicators of diminished quality of life. Copyright © 2008 John Wiley & Sons, Ltd.
Cognitive, functional and behavioral factors associated with the burden of caring for geriatric patients with cognitive impairment or depression: evidence from a South American sample
Authors: Machnicki Gerardo , Allegri Ricardo F. , Dillon Carol , Serrano Cecilia M. , Taragano Fernando E 
Published: October 2008

AbstractObjectiveTo examine behavioral, cognitive and functional factors associated with psychosocial burden in caregivers of geriatric patients.MethodsPrimary caregivers assessed were included if the geriatric patient cared for had a cognitive impairment or dementia (degenerative, vascular or mixed) (Group 1) or depression and cerebrovascular disease (CVD) (Group 2). Caregivers completed the Zarit questionnaire, the Neuropsychiatric Inventory (NPI) and Instrumental Activities of Daily Living (IADL). Patients were evaluated for dementia severity using the Clinical Dementia Rating (CDR), Mini Mental State Examination (MMSE) and Beck Depression Inventory (BDI). Structural equation modelling (SEM) was used to assess measurement models and the factors associated with burden.ResultsTwo hundred and fifty‐eight caregiver–patient pairs were included. The best model fit was obtained with a model with two constructs: function‐cognition (CDR, MMSE, and IADL) and behavior (neuropsychiatric symptoms from the NPI). In Group 1, both function (B = 0.32. T = 2.79) and behavior (B = 0.72, T = 7.84) were significantly correlated with caregiver burden, although the strength of association was more than two times higher for behavior. In Group 2, behavior was related to caregiver burden (B = 0.68, T = 6) but not function‐cognition (B = 0.16, T = 1.36).ConclusionThese findings suggest that behavioral symptoms are an important factor associated with caregiver burden in patients with cognitive impairment, dementia, or depression, while functional and cognitive factors seem to also have an influence in patients with cognitive impairment. Copyright © 2008 John Wiley & Sons, Ltd.
Subclinical atherosclerosis is weakly associated with lower cognitive function in healthy hyperhomocysteinemic adults without clinical cardiovascular disease
Authors: Gatto Nicole M. , Henderson Victor W. , St. John Jan A. , McCleary Carol , Detrano Robert , Hodis Howard N. , Mack Wendy J. 
Published: October 2008

AbstractObjectiveAtherosclerosis is the most common pathologic process underlying cardiovascular disease (CVD). It is not well known whether subclinical atherosclerosis is an independent risk factor for lower cognitive function among individuals without clinically evident CVD.MethodsWe examined cross‐sectional associations between subclinical atherosclerosis and cognitive function in a community‐based sample of otherwise healthy adults with plasma homocysteine ≥8.5 µmol/L enrolled in the BVAIT study (n = 504, mean age 61 years). Carotid artery intima‐media thickness (CIMT), coronary artery calcium (CAC) and abdominal aortic calcium (AAC) were used to measure subclinical atherosclerosis. Cognitive function was assessed with a battery of neuropsychological tests. A principal components analysis was used to extract five uncorrelated cognitive factors from scores on individual tests, and a measure of global cognition was derived. Multivariable linear regression was used to examine the association between subclinical atherosclerosis and cognitive function, adjusting for other correlates of cognition.ResultsIncreasing thickness of CIMT was associated with significantly lower scores on the verbal learning factor (β = −0.07 per 0.1 mm increase CIMT [SE(β) = 0.03], p = 0.01). CAC and AAC were not individually associated with any of the cognitive factors.ConclusionsThis study provides evidence that increasing CIMT is weakly associated with lower verbal learning abilities but not global cognition in a population of otherwise healthy middle‐to‐older aged adults with elevated plasma homocysteine levels but without clinically evident CVD. The association between CIMT and poor verbal learning may pertain particularly to men. Copyright © 2008 John Wiley & Sons, Ltd.
Behavioral health needs and problem recognition by older adults receiving home‐based aging services
Authors: Gum Amber M. , Petkus Andrew , McDougal Sarah J. , Present Melanie , King‐Kallimanis Bellinda , Schonfeld Lawrence 
Published: October 2008

AbstractObjectiveOlder adults' recognition of a behavioral health need is one of the strongest predictors of their use of behavioral health services. Thus, study aims were to examine behavioral health problems in a sample of older adults receiving home‐based aging services, their recognition of behavioral health problems, and covariates of problem recognition.MethodsThe study design was cross‐sectional. Older adults (n = 141) receiving home‐based aging services completed interviews that included: Structured Clinical Interview for DSM‐IV; Brief Symptom Inventory‐18; attitudinal scales of stigma, expectations regarding aging, and thought suppression; behavioral health treatment experience; and questions about recognition of behavioral health problems.ResultsThirty (21.9%) participants received an Axis I diagnosis (depressive, anxiety, or substance); another 17 (12.1%) were diagnosed with an adjustment disorder. Participants were more likely to recognize having a problem if they had an Axis I diagnosis, more distress on the BSI‐18, family member or friend with a behavioral health problem, and greater thought suppression. In logistic regression, participants who identified a family member or friend with a behavioral health problem were more likely to identify having a behavioral health problem themselves.ConclusionsFindings suggest that older adults receiving home‐based aging services who recognize behavioral health problems are more likely to have a psychiatric diagnosis or be experiencing significant distress, and they are more familiar with behavioral health problems in others. This familiarity may facilitate treatment planning; thus, older adults with behavioral health problems who do not report familiarity of problems in others likely require additional education. Copyright © 2008 John Wiley & Sons, Ltd.