bluuebunny/crossref_metadata_2025_split huggingface dataset:
D‐Serine metabolism in C6 glioma cells: Involvement of alanine‐serine‐cysteine transporter (ASCT2) and serine racemase (SRR) but not D‐amino acid oxidase (DAO)
Authors: Sikka Pilleriin , Walker Rosie , Cockayne Rebecca , Wood Matthew J.A. , Harrison Paul J. , Burnet Philip W.J. 
Published: January 2010

AbstractD‐serine is an endogenous N‐methyl‐D‐aspartate (NMDA) receptor coagonist. It is synthesized from L‐serine by serine racemase (SRR), but many aspects of its metabolism remain unclear, especially in the forebrain, which lacks active D‐amino acid oxidase (DAO), the major D‐serine degradative enzyme. Candidate mechanisms include SRR operating in α,β‐eliminase mode (converting D‐serine to pyruvate) and regulation by serine transport, in which the alanine‐serine‐cysteine transporter ASCT2 is implicated. Here we report studies in C6 glioma cells, which “simulate” the forebrain, in that the cells express SRR and ASCT2 but lack DAO activity. We measured D‐serine, ASCT2, SRR, and DAO expression and DAO activity in two situations: after incubation of cells for 48 hr with serine isomers and after increased or decreased SRR expression by transfection and RNA interference, respectively. Incubation with serine enantiomers decreased [3H]D‐serine uptake and ASCT2 mRNA and increased SRR immunoreactivity but did not alter DAO immunoreactivity, and DAO activity remained undetectable. SRR overexpression increased D‐serine and pyruvate and decreased [3H]D‐serine uptake and ASCT2 mRNA but did not affect DAO. SRR knockdown did not alter any of the parameters. Our data suggest that D‐serine transport mediated by ASCT2 contributes prominently to D‐serine homeostasis when DAO activity is absent. The factors regulating D‐serine are important for understanding normal NMDA receptor function and because D‐serine, along with DAO and SRR, is implicated in the pathogenesis and treatment of schizophrenia. © 2010 Wiley‐Liss, Inc.
Serum ceruloplasmin and copper are early biomarkers for traumatic brain injury‐associated elevated intracranial pressure
Authors: Dash Pramod K. , Redell John B. , Hergenroeder Georgene , Zhao Jing , Clifton Guy L. , Moore Anthony 
Published: January 2010

AbstractHigh intracranial pressure (ICP) is a prominent secondary pathology after traumatic brain injury (TBI) and is a major contributor to morbidity and mortality. Currently, there are no clinically proven methods for predicting which TBI patients will develop high ICP. In the present study, we examined whether the serum levels of the copper‐binding protein ceruloplasmin are differentially altered in patients with elevated ICP (≥25 mmHg) vs. those whose ICP remained below 20 mmHg throughout the study period. Consistent with its role as an acute‐phase reactant, we found that ceruloplasmin levels were significantly increased by 3 days post‐TBI compared with healthy volunteers. However, prior to this delayed increase, ceruloplasmin levels during the first 24 hr following injury were found to be significantly reduced in patients who subsequently developed high ICP. This decrease was found to have prognostic accuracy in delineating TBI patients based on their ICP status (cutoff of 140 μg/ml; sensitivity: 87%, specificity: 73%), Likewise, low total serum copper (below 1.32 μg/ml) was also found to be predictive of high ICP (sensitivity 86%, specificity 73%). These results suggest that initial serum ceruloplasmin/copper levels may have diagnostic value in predicting patients at risk for developing high intracranial pressure. © 2010 Wiley‐Liss, Inc.
Effects of detrital carbonate on stable oxygen and carbon isotope data from varved sediments of the interglacial Piànico palaeolake (Southern Alps, Italy)
Authors: Mangili Clara , Brauer Achim , Plessen Birgit , Dulski Peter , Moscariello Andrea , Naumann Rudolf 
Published: January 2010

AbstractContamination with detrital matter is a well‐known bias in δ18O records from lake carbonates but quantitative information of this effect is yet lacking. Therefore, we developed a new methodological approach combining isotope analyses with microfacies, X‐ray diffraction and micro‐X‐ray fluorescence data and applied this in a case study for the Piànico interglacial lake record in order to provide a quantitative estimate of the effect of detrital carbonate on stable δ18O and δ13C data. The Piànico record contains a long series of distinct and well‐preserved calcite varves and is correlated to Marine Isotope Stage 11. Intercalated in the varve sequence are detrital layers triggered by surface erosion events. These detrital layers are mainly composed of dolomite, thus reflecting the mineralogical signature of the catchment. Microfacies analyses of a 9350 varve year interval allows the identification of detrital layers down to sub‐millimetre scale and a precise selection of three different types of samples for isotope analyses: (1) pure endogenic calcite varves (five varves per sample) without detrital contamination; (2) individual detrital layers; and (3) ‘mixed’ samples including five calcite varves and up to four thin detrital layers. Detrital samples show the isotopic signature of the catchment dolomite and are up to 5.7‰ enriched in δ18O values with respect to endogenic calcite samples. In mixed samples, the degree of isotopic enrichment is directly related to the amount of detrital contamination; δ18O of bulk carbonates is significantly biased when the detrital component amounts to more than 5% of the sample. It is also shown that samples containing detrital material have an influence on the calculation of the covariance between δ13C and δ18O. Covariance is high (r = 0.76) when the correlation coefficient is calculated on the base of all samples, but absent (r = −0.43) when samples containing detrital dolomite are excluded. It has been demonstrated that microfacies analysis is a quick tool to avoid or reduce detrital contamination in bulk carbonate samples during sample selection. Copyright © 2009 John Wiley & Sons, Ltd.
Simultaneous HPLC determination of 14 tricyclic antidepressants and metabolites in human plasma
Authors: Mercolini Laura , Mandrioli Roberto , Finizio Giulia , Boncompagni Giancarlo , Raggi Maria Augusta 
Published: January 2010

AbstractA HPLC method has been developed for the simultaneous determination of seven tricyclic antidepressants (TCAs) and seven metabolites in human plasma. The analyte separation was obtained using a C8 reversed phase column and a mobile phase composed of 68% aqueous phosphate buffer at pH 3.0 and 32% ACN. The UV detector was set at 220 nm and loxapine was used as the internal standard. A careful pre‐treatment procedure for plasma samples was developed, using SPE on C2 cartridges, which gives satisfactory extraction yields (>80%) and good sample purification. The LOQs were always lower than 9.1 ng/mL and the LODs always lower than 3.1 ng/mL for all analytes. The method was successfully applied to plasma samples from depressed patients undergoing therapy with one or more TCA drugs. Precision data (RSD <8.1%), as well as accuracy results (recovery >80%), were satisfactory and no interference from other drugs was found. Hence the method seems to be suitable for the therapeutic drug monitoring of patients treated with TCAs under monotherapy or polypharmacy regimens.
Visible light initiated polymerization of styrenic monolithic stationary phases using 470 nm light emitting diode arrays
Authors: Walsh Zarah , Levkin Pavel A. , Jain Vijay , Paull Brett , Svec Frantisek , Macka Mirek 
Published: January 2010

AbstractPoly(styrene‐co‐divinylbenzene) monolithic stationary phases have been synthesized for the first time by photoinitiated polymerization. An initiator composed of (+)‐(S)‐camphorquinone/ethyl‐4‐dimethylaminobenzoate/N‐methoxy‐4‐phenylpyridinium tetrafluoroborate was activated using a 470 nm light emitting diode array as the light source. Spatially controlled polymerization of styrenic monoliths has been achieved within specific sections of a 100 μm id polytetrafluoroethylene‐coated fused‐silica capillary using simple photo masking. The sharpness of the edges was confirmed by optical microscopy, while SEM was used to verify a typical porous, globular morphology. Flow resistance data were used to assess the permeability of the monoliths and they were found to have good flow through properties with a flow resistance of 0.725 MPa/cm at 1 μL/min (water, 20°C). Conductivity profiling along the length of the capillary was used to assess their lateral homogeneity. Monoliths which were axially rotated during polymerization were found to be homogeneous along the whole length of the capillary. The monolithic stationary phases were applied to the RP gradient separation of a mixture of proteins. Column fabrication showed excellent reproducibility with the retention factor (k) having a RSD value of 2.6% for the batch and less than 1.73% on individual columns.
Photodynamic therapy of cottontail rabbit papillomavirus‐induced papillomas in a severe combined immunodeficient mouse xenograft system
Authors: Lee Richard G. , Vecchiotti Mark A. , Heaphy John , Panneerselvam Ashok , Schluchter Mark D. , Oleinick Nancy L. , Lavertu Pierre , Alagramam Kumar N. , Arnold James E. , Sprecher Robert C. 
Published: January 2010

AbstractObjectives/Hypothesis:To evaluate the efficacy of photodynamic therapy (PDT) with the phthalocyanine photosensitizer Pc 4 for treating an animal model of recurrent respiratory papillomatosis (RRP).Methods:Rabbit skin was grafted onto the dorsum of severe combined immunodeficient mice, two xenografts per animal. After the graft healed, it was inoculated with cottontail rabbit papillomavirus (CRPV). When papillomas developed, Pc 4 (0.6 or 1.0 mg/kg) was administered systemically, and 48 hours later, one papilloma of the two on each animal was exposed to 675‐nm photoactivating light at either 100 or 150 J/cm2. In addition to the contralateral tumors, which received Pc 4 but no light, other controls included animals receiving light only or neither agent. Response was assessed by measuring papilloma size with a caliper. Some papillomas and residual skin were harvested for histological assessment.Results:For the lower‐dose PDT regimens, papilloma growth rates were not significantly different from the controls. In contrast, 13 of 15 papillomas receiving the higher Pc 4 dose (1.0 mg/kg) and the higher light fluence (150 J/cm2) regressed completely and did not regrow within the observation period of up to 79 days. The response of these papillomas was significantly different from the controls (P < .001). Histological analysis confirmed the absence of residual tumor following complete response and replacement with near‐normal epithelium.Conclusions:Pc 4‐PDT is highly effective in treating virally induced (CRPV) papillomas in a murine model of RRP, and thus warrants further study as a treatment for HPV‐induced papillomas. Laryngoscope, 2010
Effect of defects on fatigue life of plates with fastener holes
Authors: Liu Y. S. , Gou B. W. , Liu J. , Yue Z. F. 
Published: January 2010

AbstractThe behavior of defects (inclusions and cavities) on fatigue life of plates with fastener holes under tensile loading has been analyzed. Special attentions have been paid on the influence of the size and location of defects on fatigue life of plates with fastener holes. Thirty‐five different finite element models of plates with different size and location of defects are established and the nominal stress method is used to estimate the fatigue lives of this models. The results show that there is a region whose center is the maximum stress point of the hole without defects. When the defect is located in this region, the influence of defects on fatigue life of plates with fastener holes is obvious. When the defects are far away form this region' center, the defects hardly influence the fatigue life of plates with fastener hole. The larger the size of the defect is, the bigger this region is. In this region, the larger the size of the defect and the shorter the distance between the defect and the region's center, the shorter the fatigue life of plates with fastener hole is.
Mild microscopic wear in the boundary lubrication regime
Authors: Bosman R. 
Published: January 2010

AbstractThe transition from a mild wear situation to a severe (adhesive) wear situation is of great interest to be able to design highly loaded concentrated contacts operating in the boundary lubricated regime. In this article a method is described to estimate this transition, based on a thermal criterion. It is stated that if a certain percentage of the contacting asperities transcends a critical temperature which is determined experimentally the transition from mild to severe wear takes place. The theory presented is validated with a model system and the results from experiments are is good agreement with the simulations.
Postconditioning protects skeletal muscle from ischemia‐reperfusion injury
Authors: Park Jong Woong , Kang Jong Woo , Jeon Woo Joo , Na Heung Sik 
Published: January 2010

AbstractIschemia‐reperfusion (I/R) injury caused by abrupt restoration of the circulation after prolonged ischemic insult induces significant morbidity after reconstructive microsurgery. The authors investigated whether a postconditioning (post‐con) procedure attenuated skeletal muscle I/R injury and protected muscular function. Three hours of complete ischemia was induced by occluding the muscular branches of rat extensor digitorum longus (EDL) muscle. The post‐con procedure was started at the end of ischemia and involved six cycles of 15 seconds of reperfusion followed by 15 seconds of re‐occlusion (3 minutes of total intervention) prior to initiating unlimited reperfusion. EDL muscle contractilities were compared with those of normal sides (no ischemic exposure), and experimental group results were also compared with control group results (3 hours of ischemia followed by full reperfusion without post‐con) at 3 hours and 5 days postreperfusion. Muscle wet weights, myeloperoxidase (MPO) activities, and histological results were also evaluated. The muscle contractilities in the post‐con group were significantly preserved at both 3 hours and 5 days postreperfusion as compared with ischemic controls. Decreased inflammatory cell infiltration, MPO activity, and wet weight of postconditioned EDL muscle suggested that post‐con attenuated acute inflammatory reactions induced by I/R. This study demonstrates that post‐con provides effective functional protection to skeletal muscles from I/R injury. © 2010 Wiley‐Liss, Inc. Microsurgery 2010.
A super‐toughened nylon 12 blends via anionic ring‐opening polymerization of lauryllactam in a twin screw extruder. Preparation, morphology, and mechanical properties
Authors: Du Libo , Yang Guisheng 
Published: January 2010

AbstractNylon 12 blends (BP) with nitrile‐butadiene ultrafine full‐vulcanized powdered rubber (NBUFPR) were successfully synthesized in a corotating intermeshing twin screw extruder via anionic ring‐opening polymerization of lauryllactam at 250°C. The in situ formed blends were characterized by mechanical test, fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. A brittle‐tough transition occurs when NBUFPR content is 4 wt%. And the notched Izod impact strength achieves 989 J m−1 when 5 wt% NBUFPR was added. Because of the good dispersion property of NBUFPR during the process ofreactive extrusion, the interparticle distance decrease remarkably. Besides, the in situ formed NBUFPR‐graft‐PA12 leads to better adhesion between the two phases. For comparison, another series of blends (BL) were also prepared by melt blending hydrolytic‐polymeric PA12 and NBUFPR in the same twin screw extruder. Brittle‐tough transition did not appear in BL blends within the same range of NBUFPR content. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers
New computational method for prediction of interacting protein loop regions
Authors: Danielson Matthew L. , Lill Markus A. 
Published: January 2010

AbstractFlexible loop regions of proteins play a crucial role in many biological functions such as protein–ligand recognition, enzymatic catalysis, and protein–protein association. To date, most computational methods that predict the conformational states of loops only focus on individual loop regions. However, loop regions are often spatially in close proximity to one another and their mutual interactions stabilize their conformations. We have developed a new method, titled CorLps, capable of simultaneously predicting such interacting loop regions. First, an ensemble of individual loop conformations is generated for each loop region. The members of the individual ensembles are combined and are accepted or rejected based on a steric clash filter. After a subsequent side‐chain optimization step, the resulting conformations of the interacting loops are ranked by the statistical scoring function DFIRE that originated from protein structure prediction. Our results show that predicting interacting loops with CorLps is superior to sequential prediction of the two interacting loop regions, and our method is comparable in accuracy to single loop predictions. Furthermore, improved predictive accuracy of the top‐ranked solution is achieved for 12‐residue length loop regions by diversifying the initial pool of individual loop conformations using a quality threshold clustering algorithm. Proteins 2010. © 2010 Wiley‐Liss, Inc.
Current status of membrane protein structure classification
Authors: Neumann Sindy , Fuchs Angelika , Mulkidjanian Armen , Frishman Dmitrij 
Published: January 2010

AbstractFor over 2 decades, continuous efforts to organize the jungle of available protein structures have been underway. Although a number of discrepancies between different classification approaches for soluble proteins have been reported, the classification of membrane proteins has so far not been comparatively studied because of the limited amount of available structural data. Here, we present an analysis of α‐helical membrane protein classification in the SCOP and CATH databases. In the current set of 63 α‐helical membrane protein chains having between 1 and 13 transmembrane helices, we observed a number of differently classified proteins both regarding their domain and fold assignment. The majority of all discrepancies affect single transmembrane helix, two helix hairpin, and four helix bundle domains, while domains with more than five helices are mostly classified consistently between SCOP and CATH. It thus appears that the structural constraints imposed by the lipid bilayer complicate the classification of membrane proteins with only few membrane‐spanning regions. This problem seems to be specific for membrane proteins as soluble four helix bundles, not restrained by the membrane, are more consistently classified by SCOP and CATH. Our findings indicate that the structural space of small membrane helix bundles is highly continuous such that even minor differences in individual classification procedures may lead to a significantly different classification. Membrane proteins with few helices and limited structural diversity only seem to be reasonably classifiable if the definition of a fold is adapted to include more fine‐grained structural features such as helix–helix interactions and reentrant regions. Proteins 2010. © 2010 Wiley‐Liss, Inc.
Negative differential conductivity in the hopping transport model
Authors: Jansson F. , Nenashev A. V. , Baranovskii S. D. , Gebhard F. , Österbacka R. 
Published: January 2010

AbstractThe effect of negative differential conductivity (NDC) in the hopping transport mode is studied by computer simulations. NDC is an important effect in a class of memory devices. Understanding the origin of NDC is vital to modeling these devices. Based on analytical arguments, it has been suggested by Shklovskii et al. that NDC can arise in the hopping model due to geometrical traps. Our computer simulations have confirmed this result. Another possibility is that the NDC is caused by Coulomb interaction between the charge carriers. This has been reported for special configurations of sites by Shin et al. We show that the NDC effect due to Coulomb interaction is not sensitive to the exact configuration of sites, and that it can appear also when the sites are placed randomly.
Doping of oligo(phenyl acetylene) with iodine vapour
Authors: Bakker R. , Weijers P. , van der Werf C. H. M. , Rath J. K. , Schropp R. E. I. 
Published: January 2010

AbstractThe doping with I2‐vapour and dopant effusion of thin films of conjugated oligomers are reported in this work. The layers have been created solvent‐free, by initiated chemical vapour deposition (iCVD). FTIR spectra show an interaction of the dopant with the phenyl ring of the oligomer. Reflectance/transmittance measurements showed a saturation of the dopant in the 400 nm thick layers after 40 min. The films change from transparent to brown‐green in the doping process and show a drastic increase in conductivity. The material is quite easily processable and can be grown at an adequate rate (∼3.5 nm/min) for thin film device applications.
UV‐sensitive optical sensors based on ITO‐gallium phosphide heterojunctions
Authors: Malik Oleksandr , Javier De la Hidalga‐Wade F. , Zúňiga‐Islas Carlos , Abundis Patiño Jesús H. 
Published: January 2010

AbstractDesign and characteristics of wide‐band UV sensors based on ITO/GaP heterostructures are discussed. Such sensors have perfect electrical parameters and high UV‐visible sensitivity in comparison with surface‐barrier structures using a semi‐transparent thin metal film as an electrode. Many applications require UV sensors with an effective rejection of visible radiation and a wide temperature operating interval.For this aim, the theoretical modelling of extreme selective optical sensors with a double Ag/ITO thin film on the GaP surface, in which the thin silver film serves as a narrow bandpass filter at 320 nm, has been conducted. With this modelling the optimal thickness combination for the silver and ITO films was found for the maximum rejection of the sensitivity to visible radiation (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical processing devices based on a‐SiC:H multilayer architectures
Authors: Vieira M. , Louro P. , Vieira M. A. , Fernandes M. , Costa J. , Fantoni A. , Barata M. A. 
Published: January 2010

AbstractRed, green and blue optical signals were directed to an a‐SiC:H multilayered device, each one with a specific transmission rate. The combined optical signal was analyzed by reading out, under different applied voltages, the generated photocurrent. Results show that when a chromatic time dependent wavelength combination with different transmission rates irradiates the multilayered structure, the device operates as a tunable wavelength filter and can be used in wavelength division multiplexing systems for short range communications. An application to fluorescent proteins detection is presented. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)