bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multiarm star‐like unimolecular micelles with a dendritic core and a dual thermosensitive shell
Authors: Luo Shizhong , Hu Xianglong , Ling Congxiang , Liu Xi , Chen Shuaishuai , Han Mengcheng 
Published: December 2010

AbstractStimuli‐responsive unimolecular polymeric micelles have attracted much interest because of their unique structures and properties. In this paper, the double phase transition behavior of unimolecular dendritic three‐layer nanostructures with dual thermoresponsive shells is studied. By using a hydrophobic hyperbranched polyester (Bolton H40)‐based macro reversible addition‐fragmentation transfer (macro‐RAFT) agent, the polymerizations of N‐isopropylacrylamide (NIPAM) and N‐isopropylmethacrylamide (NIPMAM) were conducted via the successive RAFT process. The dendritic core‐shell architecture prepared, i.e. H40‐poly(N‐isopropylacrylamide)‐block‐poly(N‐isopropylmethacrylamide) (H40‐PNIPAM‐b‐PNIPMAM), exists as unimolcular polymeric micelles with hydrophobic dendritic H40 as the core, PNIPAM as the inner shell and PNIPMAM as the corona. Upon continuous heating through the lower critical solution temperatures of PNIPAM and PNIPMAM, dendritic H40‐PNIPAM‐b‐PNIMAM exhibits two‐stage thermoresponsive collapse. Different parts of the shells of H40‐PNIPAM‐b‐PNIMAM were selectively labeled with pyrene (Py) to result in H40‐PNIPAM(Py)‐b‐PNIMAM with inner shell labeling and H40‐PNIPAM‐b‐PNIMAM(Py) with outer corona labeling. Laser light scattering, UV‐visible transmittance, micro‐differential scanning calorimetry and excimer fluorescence measurements were used in combination to probe the conformational changes of chains located at the inner layer and outer corona during the two‐stage collapse upon heating. Results from all four techniques support the double phase transition behavior of this kind of three‐layer dendritic polymer. Copyright © 2010 Society of Chemical Industry
Synthesis, characterization and properties of novel biodegradable multiblock copolymers comprising poly(butylene succinate) and poly(1,2‐propylene terephthalate) with hexamethylene diisocyanate as a chain extender
Authors: Zheng Liuchun , Li Chuncheng , Zhang Dong , Guan Guohu , Xiao Yaonan , Wang Dujing 
Published: December 2010

AbstractIn this exploration of novel biodegradable polyesters, multiblock copolymers based on poly(butylene succinate) (PBS) and poly(1,2‐propylene terephthalate) (PPT) were successfully synthesized with hexamethylene diisocyanate as a chain extender. The amorphous and rigid PPT segment was chosen to modify PBS. The structures of the polymers were characterized using1H NMR and13C NMR spectroscopy, gel permeation chromatography and wide‐angle X‐ray diffraction; the physical properties were investigated using thermogravimetric analysis, differential scanning calorimetry, mechanical testing and enzymatic degradation. The results indicate that the copolymers possess satisfactory mechanical and thermal properties, with impact strength 186% higher than that of PBS homopolymer, while tensile strength, flexural strength, thermal stability and melting point (Tm) are slightly decreased. Crystallization and biodegradation rates are still acceptable at 5 wt% PPT, although they are decreased by the introduction of PPT. The addition of appropriate amounts of PPT can improve the impact strength effectively without an obviously deleterious effect on tensile strength, flexural strength, thermal stability,Tm, crystallization rate and biodegradability. This study describes a convenient route to novel multiblock copolymers comprising crystallizable aliphatic and amorphous aromatic polyesters, which are promising for commercialization as biodegradable materials. Copyright © 2011 Society of Chemical Industry
Correlation between trunk control, respiratory muscle strength and spirometry in patients with stroke: An observational study
Authors: Jandt Sílvia Raquel , da Sil Caballero Raphael Maciel , Junior Luiz Alberto Forgiarini , Dias Alexandre Simões 
Published: December 2010

AbstractIntroduction. Stroke is the main cause of chronic disability in adults, and the effect of a stroke on the respiratory system depends on the structures affected by the lesion. Objectives. To evaluate the correlation between trunk control, respiratory muscle strength and pulmonary function in individuals who suffered stroke. Methods. Observational, quantitative and descriptive study. Twenty‐three patients who had a clinical diagnosis of ischaemic or haemorrhagic stroke. The trunk control was assessed through the Trunk Impairment Scale (TIS), and the respiratory muscle strength was assessed by manovacuometry by measuring the maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP). For pulmonary function analysis, we measured forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow (PEF) and the Tiffeneau index (TIFF) through spirometry. Results. A consistent and statistically significant correlation was found between TIS and PEF (r = 0.489, p = 0.024) and between TIS and EPmax (r = 0.517, p = 0.016). No relation was found between the other variables of pulmonary function and TIS. Conclusion. This study demonstrated that there is a relation between trunk control and respiratory muscular strength, especially concerning the expiratory muscles. However, there seems to be no relation between trunk control and pulmonary function in this series of individuals who suffered stroke. Copyright © 2010 John Wiley & Sons, Ltd.
Topology‐based modeling of intrinsically disordered proteins: Balancing intrinsic folding and intermolecular interactions
Authors: Ganguly Debabani , Chen Jianhan 
Published: December 2010

AbstractCoupled binding and folding is frequently involved in specific recognition of so‐called intrinsically disordered proteins (IDPs), a newly recognized class of proteins that rely on a lack of stable tertiary fold for function. Here, we exploit topology‐based Gō‐like modeling as an effective tool for the mechanism of IDP recognition within the theoretical framework of minimally frustrated energy landscape. Importantly, substantial differences exist between IDPs and globular proteins in both amino acid sequence and binding interface characteristics. We demonstrate that established Gō‐like models designed for folded proteins tend to over‐estimate the level of residual structures in unbound IDPs, whereas under‐estimating the strength of intermolecular interactions. Such systematic biases have important consequences in the predicted mechanism of interaction. A strategy is proposed to recalibrate topology‐derived models to balance intrinsic folding propensities and intermolecular interactions, based on experimental knowledge of the overall residual structure level and binding affinity. Applied to pKID/KIX, the calibrated Gō‐like model predicts a dominant multistep sequential pathway for binding‐induced folding of pKID that is initiated by KIX binding via the C‐terminus in disordered conformations, followed by binding and folding of the rest of C‐terminal helix and finally the N‐terminal helix. This novel mechanism is consistent with key observations derived from a recent NMR titration and relaxation dispersion study and provides a molecular‐level interpretation of kinetic rates derived from dispersion curve analysis. These case studies provide important insight into the applicability and potential pitfalls of topology‐based modeling for studying IDP folding and interaction in general. Proteins 2011; © 2011 Wiley‐Liss, Inc.
The evolution and evolutionary consequences of marginal thermostability in proteins
Authors: Goldstein Richard A. 
Published: December 2010

AbstractWhen we seek to explain the characteristics of living systems in their evolutionary context, we are often interested in understanding how and why certain properties arose through evolution, and how these properties then affected the continuing evolutionary process. This endeavor has been assisted by the use of simple computational models that have properties characteristic of natural living systems but allow simulations over evolutionary timescales with full transparency. We examine a model of the evolution of a gene under selective pressure to code for a protein that exists in a prespecified folded state at a given growth temperature. We observe the emergence of proteins with modest stabilities far below those possible with the model, with a denaturation temperature tracking the simulation temperature, despite the absence of selective pressure for such marginal stability. This demonstrates that neither observations of marginally stable proteins, nor even instances where increased stability interferes with function, provide evidence that marginal stability is an adaptation. Instead the marginal stability is the result of a balance between predominantly destabilizing mutations and selection that shifts depending on effective population size. Even if marginal stability is not an adaptation, the natural tendency of proteins toward marginal stability, and the range of stabilities that occur during evolution, may have significant effect on the evolutionary process. Proteins 2011. © 2010 Wiley‐Liss, Inc.
An automated method for consistent helix assignment using turn information
Authors: Koch Oliver , Cole Jason 
Published: December 2010

AbstractA new automated helix assignment method is presented that leads to a more consistent definition of the helix termini, especially of the helix C‐terminus. The method assigns a helix to segments of protein chain where adjacent helical turn structures are observed, capped by specific distorted turn types (e.g., open helical turns without a hydrogen bond) or capping motifs (e.g., the Schellman motif). Helix termini are detected by observing the behavior of the NH group in N‐termini and the CO group in C‐termini; in each case, the respective group must be free to interact with hydrogen bonding partners outside of the putative helix for a helix terminus to be assigned. The presented assignment method and SHAFT‐assigned helices are part of Secbase and are made available with Relibase+ 3.0 and the free web version of Relibase 3.0. The method can also be used for the helix assignments of additional protein structures. Proteins 2011; © 2011 Wiley‐Liss, Inc.
Cavitation of liquid flow in electrospray mass spectrometry especially for addition of internal calibrant in ‘accurate mass’ measurements
Authors: Lord Gwyn A. , Lim Chang‐Kee 
Published: December 2010

Abstract‘Accurate mass’ measurements in electrospray mass spectrometry are becoming more prevalent with the increasing availability of mass spectrometers with sufficient resolution. A reference compound is ideally admitted separately but almost simultaneously with the analyte and this is achieved by use of a ‘dual sprayer’ or voltage switching between reference and sample sprayers. This paper describes a novel third method, relying on cavitation (segmentation) of the liquid stream containing the reference compound, allowing the sample to ionise independently from the sample, thus preventing interference. The technique may also find application in kinetic experiments, such as protein folding studies.A high‐performance liquid chromatography (HPLC) injector was also used to provide a reference compound, producing Gaussian‐shaped profiles of varying ion intensity, thus allowing easier selection of a desirable measurement point where the intensities of the reference and analyte were similar. Copyright © 2010 John Wiley & Sons, Ltd.
Surface swabbing technique for the rapid screening for pesticides using ambient pressure desorption ionization with high‐resolution mass spectrometry
Authors: Edison Sara. E. , Lin Lora A. , Gamble Bryan M. , Wong Jon , Zhang Kai 
Published: December 2010

AbstractA rapid screening method for pesticides has been developed to promote more efficient processing of produce entering the United States. Foam swabs were used to recover a multiclass mixture of 132 pesticides from the surfaces of grapes, apples, and oranges. The swabs were analyzed using direct analysis in real time (DART) ionization coupled with a high‐resolution Exactive Orbitrap™ mass spectrometer. By using a DART helium temperature gradient from 100–350°C over 3 min, a minimal separation of analytes based on volatility differences was achieved. This, combined with the Exactive's mass resolution of 100 000, allowed the chromatographic step, along with the typical compositing and extraction steps associated with gas chromatography/mass spectrometry (GC/MS) or liquid chromatography/mass spectrometry (LC/MS) approaches, to be eliminated. Detection of 86% of the analytes present was consistently achieved at levels of 2 ng/g (per each apple or orange) and 10 ng/g (per grape). A resolution study was conducted with four pairs of isobaric compounds analyzed at a mass resolution of 100 000. Baseline separation was achieved with analyte ions differing in mass by 25 ppm and analyte ions with a mass difference of 10 ppm were partially resolved. In addition, field samples that had undergone traditional sample preparation using QuEChERS (quick, easy, cheap, rugged, and safe) were analyzed using both LC/MS and DART‐MS and the results from the two techniques were found to be comparable in terms of identification of the pesticides present. The use of swabs greatly increased sample throughput by reducing sample preparation and analysis time. Published in 2010 by John Wiley & Sons, Ltd.
Liquid chromatography/electrospray time‐of‐flight mass spectrometry for the characterisation of cyclic phosphazenes
Authors: Veldboer Katrin , Schürmann Thomas , Vogel Martin , Wiemhöfer Hans‐Dieter , Karst Uwe 
Published: December 2010

AbstractCyclic phosphazenes with different substituents were synthesised and investigated by liquid chromatography (LC) and electrospray ionisation mass spectrometry (ESI‐MS). Hexachlorocyclotriphosphazene was functionalised with aliphatic substituents as alcohols and amines, leading to product mixtures, which were subsequently analysed. In contrast to classical methods of structural analysis such as nuclear magnetic resonance (NMR) spectroscopy or X‐ray crystallography, which are restricted to pure compounds, these complex mixtures can favourably be analysed by means of LC/ESI‐MS. The main products could be separated from by‐products and, moreover, all the components of the unknown mixture were unambiguously identified by accurate mass measurements. For all compounds with different side‐chain ratios, remaining chlorine atoms or hydroxyl groups and even for spiro or ansa products, molecular structures could be suggested. Copyright © 2010 John Wiley & Sons, Ltd.
Challenges in measuring the δ13C of the soil surface CO2 efflux
Authors: Midwood Andrew J. , Millard Peter 
Published: December 2010

AbstractThe δ13C of the soil surface efflux of carbon dioxide (δ13CRS) has emerged as a powerful tool enabling investigation of a wide range of soil processes from characterising entire ecosystem respiration to detailed compound‐specific isotope studies. δ13CRS can be used to trace assimilated carbon transfer below ground and to partition the overall surface efflux into heterotrophic and autotrophic components. Despite this wide range of applications no consensus currently exists on the most appropriate method of sampling this surface efflux of CO2 in order to measure δ13CRS. Here we consider and compare the methods which have been used, and examine the pitfalls. We also consider a number of analysis options, isotope ratio mass spectrometry (IRMS), tuneable diode laser spectroscopy (TDLS) and cavity ring‐down laser spectroscopy (CRDS). δ13CRS is typically measured using chamber systems, which fall into three types: closed, open and dynamic. All are imperfect. Closed chambers often rely on Keeling plots to estimate δ13CRS, which may not be appropriate without free turbulent air mixing. Open chambers have the advantage of being able to maintain steady‐state conditions but analytical errors may become limiting with low efflux rates. Dynamic chambers like open chambers are complex, and controlling pressure fluctuations caused by air movement is a key concern. Both open and dynamic chambers in conjunction with field portable TDLS and CRDS analysis systems have opened up the possibility of measuring δ13CRS in real time permitting new research opportunities and are on balance the most suited to this type of measurement. Copyright © 2010 John Wiley & Sons, Ltd.
A New Era for Cancer Treatment: Gold‐Nanoparticle‐Mediated Thermal Therapies
Authors: Kennedy Laura C. , Bickford Lissett R. , Lewinski Nastassja A. , Coughlin Andrew J. , Hu Ying , Day Emily S. , West Jennifer L. , Drezek Rebekah A. 
Published: December 2010

AbstractNanotechnology‐based cancer treatment approaches potentially provide localized, targeted therapies that aim to enhance efficacy, reduce side effects, and improve patient quality of life. Gold‐nanoparticle‐mediated hyperthermia shows particular promise in animal studies, and early clinical testing is currently underway. In this article, the rapidly evolving field of gold nanoparticle thermal therapy is reviewed, highlighting recent literature and describing current challenges to clinical translation of the technology.
Modafinil‐induced conditioned place preference via dopaminergic system in mice
Authors: Nguyen Thi‐Lien , Tian Yu‐Hua , You In‐Jee , Lee Seok‐Yong , Jang Choon‐Gon 
Published: December 2010

AbstractModafinil, a psychostimulant, is used in the treatment of narcolepsy, shift work sleep disorder, and excessive daytime sleepiness associated with obstructive sleep apnea. Preclinical and clinical studies suggest that modafinil may have reinforcing effects. However, a possible rewarding property of modafinil has not been fully investigated. In this study, we assessed the potential rewarding property of modafinil using the conditioned place preference (CPP) paradigm in mice. Using radiolabeled ligands, we observed changes in dopamine, glutamate, and GABA receptor binding in the brains of mice after treatment with modafinil. Modafinil produced significant CPP in mice at an intraperitoneal (i.p.) dose of 125 mg kg−1and prevented normal body weight gain of mice in a dose‐dependent manner. A significant reduction in normal body weight gain was observed when mice were administrated 125 mg kg−1modafinil. In addition, there were widespread changes in receptor binding in the brains of modafinil‐treated mice; Dopamine D1binding was increased in the caudate putamen, the accumbens, and the substantia nigra, while dopamine D2binding was decreased in the caudate putamen and the accumbens. Dopamine transporter (DAT) binding was increased in the prefrontal cortex, the caudate putamen, and the nucleus accumbens. No changes were observed in NMDA and GABAAreceptor binding. These data indicate that modafinil had a significant rewarding property and could be abused as a recreational drug. Dopamine systems may play a key role in the rewarding property of modafinil. Synapse, 2011. © 2010 Wiley‐Liss, Inc.
123I‐NKJ64: A novel single photon emission computed tomography radiotracer for imaging the noradrenaline transporter in brain
Authors: Tavares Adriana Alexandre S. , Jobson Nicola K. , Dewar Deborah , Sutherland Andrew , Pimlott Sally L. 
Published: December 2010

AbstractDysregulation of noradrenergic function has been implicated in a variety of psychiatric and neurodegenerative disorders, including depression and Alzheimer's disease. The noradrenaline transporter (NAT) is a major target for antidepressant drugs, including reboxetine, a selective noradrenaline reuptake inhibitor. Therefore, the development of a radiotracer for imaging of the NAT is desirable. In this study, NKJ64, a novel iodinated analog of reboxetine, was radiolabeled and evaluated as a potential single photon emission computerized tomography (SPECT) radiotracer for imaging the NAT in brain. Biological evaluation of the novel radiotracer,123/125I‐NKJ64, was carried out in rats using: in vitro ligand binding assays; in vitro and ex vivo autoradiography; in vivo biodistribution studies and ex vivo pharmacological blocking studies.125I‐NKJ64 displayed saturable binding with high affinity for NAT in cortical homogenates (KD= 4.82 ± 0.87 nM, mean ± SEM,n= 3). In vitro and ex vivo autoradiography showed the regional distribution of123I‐NKJ64 binding to be consistent with the known density of NAT in brain. Following i.v. injection there was rapid uptake of123I‐NKJ64 in brain, with maximum uptake of 2.93% ± 0.14% (mean ± SEM,n= 3) of the injected dose. The specific to nonspecific ratio (locus coeruleus:caudate putamen) of123I‐NKJ64 uptake measured byex vivoautoradiography was 2.8 at 30 min post i.v. injection. The prior administration of reboxetine significantly reduced the accumulation of123I‐NKJ64 in the locus coeruleus (>50% blocking). The data indicate that further evaluation of123I‐NKJ64 in nonhuman primates is warranted in order to determine its utility as a SPECT radiotracer for imaging of NAT in brain. Synapse , 2011. © 2010 Wiley‐Liss, Inc.
Allantoic cysts and posterior urethral valves: a case report
Authors: Bureau M. , Bolduc S. 
Published: December 2010

AbstractAllantoic cysts are a somewhat rare entity. They are identifiable on antenatal ultrasound examination but are not easily distinguishable from pseudocysts, which are often associated with a poor prognosis. Their etiology remains obscure and obstructive uropathies have been proposed to be one of the underlying mechanisms. We report on a case in which both allantoic cysts and a patent urachus were detected antenatally and turned out to be associated with posterior urethral valves (PUV). The cysts were first seen in the early second trimester, with a full fetal bladder and patent urachus. They disappeared by the 29th week. During the subsequent sonographic examinations, the bladder was emptying regularly. The kidneys remained normal throughout the pregnancy. It is hypothesized that the increased pressure within the urinary tract kept the urachus patent, led to the formation of allantoic cysts and, later, to their perforation; this allowed the fetus to empty his bladder and kept him from the usual complications of PUV. This case emphasizes the importance of detection and characterization of umbilical cord cysts on antenatal ultasound examination and suggests that obstructive uropathies should be included in the differential diagnosis of umbilical cord cyst communicating with the fetal bladder. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
‘Good’ or ‘bad’ wind power forecasts: a relative concept
Authors: Bessa R. J. , Miranda V. , Botterud A. , Wang J. 
Published: December 2010

AbstractThis paper reports a study on the importance of the training criteria for wind power forecasting and calls into question the generally assumed neutrality of the ‘goodness’ of particular forecasts. The study, focused on the Spanish Electricity Market as a representative example, combines different training criteria and different users of the forecasts to compare them in terms of the benefits obtained. In addition to more classical criteria, an information theoretic learning training criterion, called parametric correntropy, is introduced as a means to correct problems detected in other criteria and achieve more satisfactory compromises among conflicting criteria, namely forecasting value and quality. We show that the interests of wind farm owners may lead to a preference for biased forecasts, which may be in conflict with the larger needs of secure operating policies. The ideas and conclusions are supported by results from three real wind farms. Copyright © 2010 John Wiley & Sons, Ltd.