bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temperature‐Regulated Fluorescence Characteristics of Supramolecular Assemblies Formed By a Smart Polymer and a Conjugated Polyelectrolyte
Authors: Inal Sahika , Kölsch Jonas D. , Chiappisi Leonardo , Kraft Mario , Gutacker Andrea , Janietz Dietmar , Scherf Ullrich , Gradzielski Michael , Laschewsky André , Neher Dieter 
Published: December 2012

AbstractAqueous mixtures of a coumarin‐labeled non‐ionic thermoresponsive copolymer and a cationic polythiophene exhibit marked changes in their fluorescence properties upon heating. At room temperature, emission from the label is significantly quenched due to energy transfer to the conjugated polyelectrolyte. Heating the mixture reduces the energy‐transfer efficiency markedly, resulting in a clearly visible change of the emission color. Although the two macromolecules associate strongly at room temperature, the number of interacting sites is largely reduced upon the phase transition. Crucially, the intermolecular association does not suppress the responsiveness of the smart polymer, meaning that this concept should be applicable to chemo‐ or bioresponsive polymers with optical read‐out, for example, as a sensor device.
Oxidation‐Responsive Polymers: Which Groups to Use, How to Make Them, What to Expect From Them (Biomedical Applications)
Authors: Lallana Enrique , Tirelli Nicola 
Published: December 2012

AbstractDramatic physical changes may take place upon the occurrence of oxidation reactions in a polymer, for example, solubilization or crosslinking. These effects can be used to perform responsive actions such as modulating the release kinetics of a drug with the extent of oxidation. The relevance of oxidation‐responsive applications to the biomedical/pharmaceutical field is discussed, starting from a review of chemical groups that can respond to physiologically occurring oxidants. An overview of the preparative processes of polymers containing groups such as metallocenes, (poly)pyridyl metal complexes, polyconjugated sequences, thiols, thioethers (sulfides), and stannanes is presented, and the mechanisms of oxidative response are reviewed.
Bioinspired Photo‐Core‐Crosslinked and Noncovalently Connected Micelles From Functionalized Polystyrene and Poly(ethylene oxide) Homopolymers
Authors: Wu Yi‐Chen , Wu Yu‐Shian , Kuo Shiao‐Wei 
Published: December 2012

AbstractIn this paper, we report a simple and effective method for the preparation of stable core‐crosslinked micelles after the self‐assembly of thymine‐functionalized polystyrene (PVBT) and adenine‐terminated poly(ethylene oxide) (PEO‐A) homopolymers, and subsequent bioinspired photo‐crosslinking of the thymine units in PVBT. We obtained “graft‐like” copolymers from the interactions of PEO‐A with the PVBT chains through complementary multiple hydrogen bonding in a common solvent (dimethylformamide) after the addition of selective solvents (H2O and MeCN for PVBT and PEO‐A, respectively). Stable micelles featuring PVBT as the core and PEO‐A as the shell were formed via selective solvent pairs; they were clearly visualized using transmission electronic microscopy and staining techniques. The shapes and sizes of the core/shell micelle structures did not change after exposure to UV light, revealing the enhanced dimensional stability of these photo‐core‐crosslinked micelles.
Rejuvenation, Aging, and Confinement Effects in Atactic‐Polystyrene Films Subjected to Oscillatory Shear
Authors: Hudzinskyy Dmytro , Michels Matthias A. J. , Lyulin Alexey V. 
Published: December 2012

AbstractMolecular‐dynamics simulations of 5 nm‐thick atactic‐polystyrene films have been used to study the influence of cyclic‐shear deformation on the stress–strain behavior and local segmental mobility. Upon cyclic yield the stress–strain behavior of the films slowly evolves towards a steady state which is characterized by a decrease of the maximum stress and by an enhanced dissipative process. Immediately after plastic deformation the storage modulus is decreased and the loss modulus is increased as compared with their initial values. Such changes in the viscoelastic moduli reflect the mechanical rejuvenation of a polymer glass. This mechanical rejuvenation of polymers is connected to the increase in the simulated segmental mobility, which is calculated for the entire film as well as in different layers. magnified image
Levodopa improves motor deficits but can further disrupt cognition in a macaque parkinson model
Authors: Schneider Jay S. , Pioli Elsa Y. , Jianzhong Yang , Li Qin , Bezard Erwan 
Published: December 2012

BackgroundLevodopa effectively relieves motor symptoms in Parkinson's disease (PD), but has had inconsistent effects on cognition, even worsening some aspects of cognitive functioning. Therefore, remediation of PD cognitive deficits is a major unmet need. However, drug development efforts have been hampered by lack of an animal model in which motor and cognitive deficits can be examined simultaneously.MethodsCynomolgus monkeys were trained to perform cognitive tasks and then chronically exposed to MPTP to slowly produce cognitive and motor deficits of parkinsonism.ResultsAdministration of L‐dopa to these animals dose dependently improved motor functioning, but did not significantly improve cognitive performance. At doses that maximally improved motor function, additional cognitive deficits were observed. The present model of MPTP‐induced parkinsonism recapitulates important motor and cognitive aspects of PD. Results with L‐dopa mirror data derived from PD patients.ConclusionThis model should allow more efficient testing of potential PD therapeutics to evaluate motor and cognitive functions simultaneously. © 2012 Movement Disorder Society
Atherosclerotic Risk Factors, Vascular Cognitive Impairment, and Alzheimer Disease
Authors: Kovacic Jason C. , Fuster Valentin 
Published: December 2012

AbstractThe involvement of vascular factors in Alzheimer dementia was first appreciated over 100 years ago. Recently, significant advances in our understanding of these brain‐vascular relationships have taken place. Vascular cognitive impairment is now recognized as a distinct group of interrelated vascular‐based neurological insults that can accumulate and lead to dementia. Importantly, the pathology of vascular cognitive impairment extends far beyond brain destruction wrought by major stroke. Other subtle changes may also arise that contribute to vascular cognitive impairment and dementia, including subclinical stroke, white‐matter changes such as hyperintensities and lipohyalinosis, small lacunar infarcts, cerebral hypoperfusion, and compromise of the blood‐brain barrier. In this review we critically examine the emerging body of evidence that relates atherosclerotic risk factors, brain functioning, and Alzheimer disease. Mt Sinai J Med 79:664–673, 2012. © 2012 Mount Sinai School of Medicine
Evaluating Efficacy of Pharmaceutical Interventions in Atherosclerosis: Role of Magnetic Resonance Imaging and Positron Emission Tomography
Authors: Hyafil Fabien , Feldman Laurent , Le Guludec Dominique , Fayad Zahi A. 
Published: December 2012

AbstractThe rate of acute complications of atherosclerosis (acute myocardial infarction, ischemic stroke) has continuously decreased over the last 20 years in Western countries. This is largely explained by improvements in the reduction and treatment of cardiovascular risk factors and by the increasing number of patients who benefit from preventive treatments such as antiplatelet, lipid‐lowering, or antihypertensive drugs. This means also that, when testing new drugs aimed at either halting or even reversing the progression of atherosclerotic plaques, a large number of patients will need to be included in clinical trials to demonstrate an improvement in patient outcome with the drugs. Pharmaceutical companies are therefore looking for early surrogate markers that could be evaluated in a small number of patients to predict the beneficial effects of new drugs on atherosclerotic plaques before moving to costly clinical trials with a large number of patients. In this review, we will discuss the place of atherosclerotic plaque imaging with magnetic resonance imaging and positron emission tomography for the evaluation of new antiatherosclerotic drugs. Mt Sinai J Med 79:689–704, 2012. © 2012 Mount Sinai School of Medicine
Amyloid Neuropathies
Authors: Shin Susan C. , Robinson‐Papp Jessica 
Published: December 2012

AbstractPeripheral neuropathy is a common complication of many of the systemic amyloidoses. Although the cause of neuropathy is not entirely clear, it is likely related to amyloid deposition within the nerve. This may lead to focal, multifocal, or diffuse neuropathies involving sensory, motor and/or autonomic fibers. The presenting symptoms depend on the distribution of nerves affected. One of the most common phenotypes is sensorimotor polyneuropathy, which is characterized by symptoms of neuropathic pain, numbness, and in advanced cases weakness. Symptoms begin in the feet and ultimately progress to the proximal legs and hands. The most common focal neuropathy is a median neuropathy at the wrist, clinically known as carpal tunnel syndrome. Carpal tunnel symptoms may include pain and sensory disturbances in the lateral palm and fingers; hand weakness may ensue if the focal neuropathy is severe. Autonomic neuropathy may affect a variety of organ systems such as the cardiovascular, gastrointestinal, and genitourinary systems. Symptoms may be non‐specific making the diagnosis of autonomic neuropathy more difficult to identify. However, it is important to recognize and distinguish autonomic neuropathy from diseases of the end‐organs themselves. This article reviews the inherited and acquired amyloidoses that affect the peripheral nervous system including familial amyloid polyneuropathy, and primary, secondary and senile amyloidosis. We emphasize the clinical presentation of the neurologic aspects of these diseases, physical examination findings, appropriate diagnostic evaluation, treatment and prognosis. Mt Sinai J Med 79:733–748, 2012. © 2012 Mount Sinai School of Medicine
Cancer recording and mortality in the General Practice Research Database and linked cancer registries
Authors: Boggon Rachael , van Staa Tjeerd P. , Chapman Michael , Gallagher Arlene M. , Hammad Tarek A. , Richards Mike A. 
Published: December 2012

ABSTRACTPurposeLarge electronic datasets are increasingly being used to evaluate healthcare delivery. The aim of this study was to compare information held by cancer registries with that of the General Practice Research Database (GPRD).MethodsA convenience sample of 101 020 patients aged 40+ years drawn from GPRD formed the primary data source. This cohort was derived from a larger sample originally established for a cohort study of diabetes. GPRD records were linked with those from cancer registries in the National Cancer Data Repository (NCDR). Concordance between the two datasets was then evaluated. For cases recorded only on one dataset, validation was sought from other datasets (Hospital Episode Statistics and death registration) and by detailed analysis of a subset of GPRD records.ResultsA total of 5797 cancers (excluding non‐melanomatous skin cancer) were recorded on GPRD. Of these cases, 4830 were also recorded on NCDR (concordance rate of 83.3%). Of the 976 cases recorded on GPRD but not on NCDR, 528 were present also in the hospital records or death certificates. Of the 341 cases recorded on NCDR but not on GPRD, 307 were recorded in these other two datasets. Rates of concordance varied by cancer type. Cancer registries recorded larger numbers of patients with lung, colorectal, and pancreatic cancers, whereas GPRD recorded more haematological cancers and melanomas. As expected, GPRD recorded significantly more non‐melanomatous skin cancer. Concordance decreased with increasing age.ConclusionAlthough concordance levels were reasonably high, the findings from this study can be used to direct efforts for better recording in both datasets. Copyright © 2012 Crown copyright.
An automated tool for detecting medication overuse based on the electronic health records
Authors: Salmasian Hojjat , Freedberg Daniel E , Abrams Julian A , Friedman Carol 
Published: December 2012

ABSTRACTPurposeMedication overuse is a serious concern in healthcare as it leads to increased expenditures, side effects, and morbidities. Identifying overuse is only possible through excluding appropriate indications that are primarily mentioned in unstructured notes. We developed a framework for automatic identification of medication overuse and applied it to proton pump inhibitors (PPIs).MethodsWe first created an indications knowledge base using data from drug labels, clinical guidelines, expert opinion, and other sources. We also obtained the list of current problems for 200 randomly selected inpatients who received PPIs using a natural language processing system and the discharge summaries of those patients. These problems were checked against the indications knowledge base to identify overuse candidates. Two gastroenterologists manually reviewed the notes and identified cases of overuse. Results from the automated framework were compared with the manual review.ResultsReviewers had high interrater reliability in finding indications (agreement = 92.1%, Cohen's κ = 0.773). In 137 notes included in the final analysis, our system identified indications with a sensitivity of 74% (95%CI = 59–86) and specificity of 95% (95%CI = 87–98). In cases of appropriate use where the automated system also found one or more indications, it always included the correct indication.ConclusionsWe created an automated system that can identify established indications of medication use in electronic health records with high accuracy. It can provide clinical decision support for identifying potential overuse of PPIs and could be useful for reducing overuse and encouraging better documentation of indications. Copyright © 2012 John Wiley & Sons, Ltd.
Synthesis, characterization, and CO2 permeation properties of acetylene‐terminated polyimide membranes
Authors: Kanehashi Shinji , Onda Masaki , Shindo Ryohei , Sato Shuichi , Kazama Shingo , Nagai Kazukiyo 
Published: December 2012

AbstractA novel fluorine‐containing telechelic polyimide end‐capped with acetylene group which derived from 4,4‐(hexafluoroisopropylidene) diphthalic anhydride (6FDA), 3,4‐diaminodiphenyl ether (DADE), and 4‐(2‐phenylethynyl) phthalic anhydride (PEPA) was synthesized using polycondensation. The physical and CO2 permeation properties of its crosslinked membranes prepared by the cyclotrimerization reaction of the acetylene groups at the polymer chain end using tantalum (V) chloride (TaCl5) as a catalyst under thermal treatment was investigated in terms of CO2‐induced membrane plasticization. The crosslinked membranes showed a gel content in organic solvent, which was good solvent of noncrosslinked membranes, and improved their thermal stability. Based on the measurement of the high‐pressure time dependence on CO2 permeation, the crosslinked 6FDA–DADE–PEPA membranes exhibited more resistance to CO2‐induced plasticization than noncrosslinked 6FDA–DADE and thermal treated 6FDA–DADE–PEPA. Furthermore, the increase in TaCl5 content resulted in more resistance to plasticization. The cyclotrimerization reaction of the acetylene groups at the polymer chain ends using a transition metal catalyst under thermal treatment was found to be more effective than conventional thermal treatments for suppressing membrane plasticization without the membrane densification. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Accelerated irradiance and temperature cycle test for amorphous silicon photovoltaic devices
Authors: Igari Sanekazu , Takahisa Kiyoshi 
Published: December 2012

ABSTRACTAn accelerated irradiance and temperature cycle test (AITCT) has been developed as a method to evaluate the long‐term performance stability of amorphous silicon (a‐Si) photovoltaic (PV) devices. The AITCT simulates the daily light–dark cycle in 6 min (0.1 h). It also simulates the annual temperature cycle while controlling the temperature at 45 °C above the average monthly outdoor ambient temperature. This allows the influence of the day–night cycle and seasonal variation to be included in the acceleration factor for single‐junction a‐Si PV devices. The initial degradation and seasonal variation of performance of a‐Si PV devices simulated by the AITCT agreed well with experimental results of 4‐year outdoor exposure. Subsequent tests with the AITCT equivalent of 30‐year outdoor exposure revealed that rapid degradation in the efficiency of a‐Si PV devices would not occur by repeating the cyclic changes corresponding to seasonal variations following the initial degradation. The AITCT is able to accelerate further recovery in addition to light‐induced degradation. Furthermore, the AITCT is applicable to other PV devices with light‐intensity dependencies related to light‐induced degradation as well as thermal recovery dependencies, such as multi‐junction PV devices consisting of a‐Si layers and other materials. This point will be discussed. Copyright © 2012 John Wiley & Sons, Ltd.
Influence of the substrate material on the surface morphology of electrochemically deposited ZnO layers
Authors: Dimova‐Malinovska Doriana , Lovchinov Konstantin , Ganchev Maxim , Angelov Orlin , Graff Joachim Seland , Ulyashin Alexander 
Published: December 2012

AbstractIn this paper we report results of fabrication of ordered ZnO nanorods (NRs) or nanowalls (NWs) electrochemically deposited on different highly conductive substrates. The following types of conductive substrates have been used: (i) highly doped p‐type multi‐crystalline Si, and (ii) copper thin plates. The influence of a seeding Ag layer deposited on multi‐Si substrates on the growth of ZnO NRs has been studied as well. It is observed that morphology of the deposited ZnO structures depends strongly on the type of the substrate used. It is found that ZnO structures with different shapes, such as NRs, nanotubes or NWs can be grown on top of highly conductive substrates used in this work. It is observed that optical reflection of the deposited layers depends on the substrate used as well as on the time of the electrochemical deposition of ZnO layers. It was found that: (i) for ZnO NWs/Cu structures, diffused reflection exhibit strong enhancement compared to pure Cu substrate; (ii) in case of ZnO NRs/Si structures reflection is decreased compared to that for pure Si substrate. Possible applications of ZnO NRs or NWs‐based structures for the processing of advanced Si‐based solar cells are discussed.
Fragmentation patterns of protonated amino acids formed by atmospheric pressure chemical ionization
Authors: Choi Sung‐Seen , Song Min Ju , Kim Ok‐Bae , Kim Yeowool 
Published: December 2012

RATIONALEDissociation reactions of protonated amino acids (AAs) can be used as models for the fragmentation of protonated peptides. Atmospheric pressure chemical ionization mass spectrometry (APCI‐MS) provides a great deal of structural information in a short analysis time.METHODSIn APCI‐MS, the fragmentation patterns can be obtained by varying the cone voltage and some fragment ions are produced that can be used to identify the structure of an analyte. In general, the fragmentation of AAs has used liquid chromatography/tandem mass spectrometry (LC/MS/MS). However, we studied the fragmentation of protonated AAs using a single quadrupole mass spectrometer.RESULTSThe principal fragment ions were [M + H – H2O – CO]+, [M + H – H2O]+, and [M + H – NH3]+. AAs that only generated [M + H – H2O – CO]+ were alanine, glycine, histidine, isoleucine, leucine, proline, phenylalanine, and valine. AAs that generated [M + H – H2O]+ and [M + H – H2O – CO]+ were aspartic acid, glutamic acid, serine, and threonine, while AAs that generated [M + H – NH3]+ and [M + H – H2O – CO]+ were asparagine, cysteine, glutamine, methionine, tryptophan, and tyrosine. Arginine and lysine generated [M + H – H2O]+ and [M + H – NH3]+.CONCLUSIONSThe relative abundances of the fragment ions increased with increase in the cone voltage. The experimental results were explained by the favorability of the intermediate structure and the stability of the fragment ion structure. The specific fragmentation patterns could be used for differentiating underivatized AAs. Copyright © 2012 John Wiley & Sons, Ltd.
Fragmentation studies of SIRT1‐activating drugs and their detection in human plasma for doping control purposes
Authors: Höppner Sebastian , Schänzer Wilhelm , Thevis Mario 
Published: December 2012

RATIONALEThe efficiency of Sirtuin1, a major target for the treatment of various metabolic disorders such as inflammation and type 2 diabetes mellitus, can be modulated via low molecular mass SIRT1 activators (e.g. resveratrol, SRT1720, and SRT2104).The administration of such compounds results in increased deacetylation of substrates including p53, FOXO1, and PGC1alpha, potentially leading to an improved physical performance. Consequently, proactive and preventive anti‐doping measures are required and an assay dedicated to serum and plasma was desirable.METHODSModel substances of emerging SIRT1 drug candidates were obtained and synthesized and their mass spectrometric behavior following positive or negative electrospray ionization and collision‐induced dissociation was elucidated using low and high resolution/high accuracy (tandem) mass spectrometry. Subsequently, a screening and confirmation procedure necessitating 100 μL of plasma was established employing liquid chromatography/tandem mass spectrometry (LC/MS/MS) based on diagnostic ion transitions recorded in multiple reaction monitoring mode. Sample preparation consisted of the addition of two deuterated internal standards (D8‐SRT1720 and D4‐resveratrol) to the plasma specimen and subsequent protein precipitation.RESULTSCharacteristic product ions indicative of the core structures of the model analytes were characterized and utilized for the development of a multi‐analyte LC/MS/MS detection method applicable to sports drug testing programs. The doping control assay was validated with regard to specificity, limits of detection (0.1–1 ng/mL), recoveries (90–98%), intraday and interday precisions (2–18%), and ion suppression/enhancement effects.CONCLUSIONSThe fragmentation pathways of SRT1720 and 4 SIRT1 activator models based on a common thiazole‐imidazole nucleus as well as two different complementary activators (SIRT1 activator 3 and CAY10602), comprising a quinoxaline core, were studied. The resulting information was used to establish and validate a sports drug testing methodology relevant for an efficient and timely anti‐doping procedure, targeting a new class of emerging therapeutics possessing significant potential for misuse in elite and amateur sport. Copyright © 2012 John Wiley & Sons, Ltd.