bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhanced system design for download and streaming services using Raptor codes
Authors: Gasiba Tiago , Xu Wen , Stockhammer Thomas 
Published: February 2008

AbstractRaptor codes have been recently standardised by 3rd Generation Partnership Project (3GPP) to be used in the application layer (AL) for multimedia broadcast and multicast services (MBMS) including download delivery and streaming delivery. Furthermore, digital video broadcast (DVB) has also recommended the inclusion of these Raptor codes for IP‐datacast services. In this paper, enhancements on the system and receiver design using Raptor codes are studied, namely the permeable layer receiver (PLR) and the individual post‐repair mechanism. With the PLR, the partial information ignored in the conventional receiver is passed from lower layer to higher layer. We show how a practical and efficient implementation of the Raptor decoder as a PLR can be done, which can not only achieve huge performance gains, but the gains can be achieved at an affordable low decoding complexity. Whereas the PLR is employed for enhancing both download and streaming services, the post‐repair aims at guaranteeing reliable download delivery when a feedback channel is available. We propose here two efficient post‐repair algorithms which fully exploit the properties of the Raptor codes. One allows to find a minimum set of source symbols to be requested in the post‐delivery, and another allows to find a sufficient number of consecutive repair symbols. Selected simulations verify the good performance of proposed techniques. Copyright © 2008 John Wiley & Sons, Ltd.
Comparison of approaches for machine‐learning optimization of neural networks for detecting gene‐gene interactions in genetic epidemiology
Authors: Motsinger‐Reif Alison A. , Dudek Scott M. , Hahn Lance W. , Ritchie Marylyn D. 
Published: February 2008

AbstractThe detection of genotypes that predict common, complex disease is a challenge for human geneticists. The phenomenon of epistasis, or gene‐gene interactions, is particularly problematic for traditional statistical techniques. Additionally, the explosion of genetic information makes exhaustive searches of multilocus combinations computationally infeasible. To address these challenges, neural networks (NN), a pattern recognition method, have been used. One limitation of the NN approach is that its success is dependent on the architecture of the network. To solve this, machine‐learning approaches have been suggested to evolve the best NN architecture for a particular data set. In this study we provide a detailed technical description of the use of grammatical evolution to optimize neural networks (GENN) for use in genetic association studies. We compare the performance of GENN to that of a previous machine‐learning NN application—genetic programming neural networks in both simulated and real data. We show that GENN greatly outperforms genetic programming neural networks in data sets with a large number of single nucleotide polymorphisms. Additionally, we demonstrate that GENN has high power to detect disease‐risk loci in a range of high‐order epistatic models. Finally, we demonstrate the scalability of the GENN method with increasing numbers of variables—as many as 500,000 single nucleotide polymorphisms.Genet. Epidemiol. 2008. © 2008 Wiley‐Liss, Inc.
Redistribution or horizontal equity in Hong Kong's mixed public–private health system: a policy conundrum
Authors: Leung Gabriel M. , Tin Keith Y. K. , O'Donnell Owen 
Published: February 2008

AbstractWe examine the distributional characteristics of Hong Kong's mixed public–private health system to identify the net redistribution achieved through public spending on health care, compare the income‐related inequality and inequity of public and private care and measure horizontal inequity in health‐care delivery overall. Payments for public care are highly concentrated on the better‐off whereas benefits are pro‐poor. As a consequence, public health care effects significant net redistribution from the rich to the poor. Public care is skewed towards the poor in part not only because of allocation according to need but also because the rich opt out of the public sector and consume most of the private care. Overall, there is horizontal inequity favouring the rich in general outpatient care and (very marginally) inpatient care. Pro‐rich bias in the distribution of private care outweighs the pro‐poor bias of public care. A lesser role for private finance may improve horizontal equity of utilisation but would also reduce the degree of net redistribution through the public sector. Copyright © 2008 John Wiley & Sons, Ltd.
Energy metabolism transition in multi‐cellular human tumor spheroids
Authors: Rodríguez‐Enríquez Sara , Gallardo‐Pérez Juan Carlos , Avilés‐Salas Alejandro , Marín‐Hernández Alvaro , Carreño‐Fuentes Liliana , Maldonado‐Lagunas Vilma , Moreno‐Sánchez Rafael 
Published: February 2008

AbstractIt is thought that glycolysis is the predominant energy pathway in cancer, particularly in solid and poorly vascularized tumors where hypoxic regions develop. To evaluate whether glycolysis does effectively predominate for ATP supply and to identify the underlying biochemical mechanisms, the glycolytic and oxidative phosphorylation (OxPhos) fluxes, ATP/ADP ratio, phosphorylation potential, and expression and activity of relevant energy metabolism enzymes were determined in multi‐cellular tumor spheroids, as a model of human solid tumors. In HeLa and Hek293 young‐spheroids, the OxPhos flux and cytochrome c oxidase protein content and activity were similar to those observed in monolayer cultured cells, whereas the glycolytic flux increased two‐ to fourfold; the contribution of OxPhos to ATP supply was 60%. In contrast, in old‐spheroids, OxPhos, ATP content, ATP/ADP ratio, and phosphorylation potential diminished 50–70%, as well as the activity (88%) and content (3 times) of cytochrome c oxidase. Glycolysis and hexokinase increased significantly (both, 4 times); consequently glycolysis was the predominant pathway for ATP supply (80%). These changes were associated with an increase (3.3 times) in the HIF‐1α content. After chronic exposure, both oxidative and glycolytic inhibitors blocked spheroid growth, although the glycolytic inhibitors, 2‐deoxyglucose and gossypol (IC50 of 15–17 nM), were more potent than the mitochondrial inhibitors, casiopeina II‐gly, laherradurin, and rhodamine 123 (IC50 > 100 nM). These results suggest that glycolysis and OxPhos might be considered as metabolic targets to diminish cellular proliferation in poorly vascularized, hypoxic solid tumors. J. Cell. Physiol. 216: 189–197, 2008. © 2008 Wiley‐Liss, Inc.
Regulation of Na+/H+ exchanger 1 allosteric balance by its localization in cholesterol‐ and caveolin‐rich membrane microdomains
Authors: Tekpli Xavier , Huc Laurence , Lacroix Jérôme , Rissel Mary , Poët Mallorie , Noël Josette , Dimanche‐Boitrel Marie‐Thérèse , Counillon Laurent , Lagadic‐Gossmann Dominique 
Published: February 2008

AbstractThe Na+/H+ exchanger 1, which plays an essential role in intracellular pH regulation in most tissues, is also known to be a key actor in both proliferative and apoptotic processes. Its activation by H+ is best described by the Monod–Wyman–Changeux model: the dimeric NHE‐1 oscillates between a low and a high affinity conformation, the balance between the two forms being defined by the allosteric constant L0. In this study, influence of cholesterol‐ and caveolin‐rich microdomains on NHE‐1 activity was examined by using cholesterol depleting agents, including methyl‐β‐cyclodextrin (MBCD). These agents activated NHE‐1 by modulating its L0 parameter, which was reverted by cholesterol repletion. This activation was associated with NHE‐1 relocation outside microdomains, and was distinct from NHE‐1 mitogenic and hormonal stimulation; indeed MBCD and serum treatments were additive, and serum alone did not change NHE‐1 localization. Besides, MBCD activated a serum‐insensitive, constitutively active mutated NHE‐1 (625KDKEEEIRK635 into KNKQQQIRK). Finally, the membrane‐dependent NHE‐1 regulation occurred independently of Mitogen Activated Protein Kinases, especially Extracellular Regulated Kinase activation, although this kinase was activated by MBCD. In conclusion, localization of NHE‐1 in membrane cholesterol‐ and caveolin‐rich microdomains constitutes a novel physiological negative regulator of NHE‐1 activity. J. Cell. Physiol. 216: 207–220, 2008. © 2008 Wiley‐Liss, Inc.
Hepatocyte growth factor modulates Sertoli–Sertoli tight junction dynamics
Authors: Catizone A. , Ricci G. , Galdieri M. 
Published: February 2008

AbstractIn mammalian testes Sertoli cells form tight junctions whose function is fundamental for the maintenance of a normal spermatogenesis. Hepatocyte growth factor (HGF) is a cytokine influencing the cellular tight junctions either in normal or in tumor cells. We have previously demonstrated that HGF is expressed in the rat testis and influences many functional activities of somatic and germ cells. We now report that HGF decreases the levels of testicular occludin and influences the position of the molecule in the tight junctions as demonstrated by confocal microscopy analysis. In fact in the presence of the factor occludin was mainly localized in the suprabasal region of the tubules whereas in its absence occludin was prevalently localized in the basal region. Occludin production is known to be regulated by different cytokines including TGFβ. We have investigated the role of HGF in the regulation of the levels of TGFβ and we report that HGF significantly increases the amount of the active fraction of the factor without affecting the amount of the total TGFβ. Urokinase type plasminogen activator (uPA) is closely related with the tight junctions and is one of the molecules able to activate the inactive TGF‐β. We found that HGF significantly increases the amount of uPA present in the testis suggesting that HGF regulates the amount of active TGFβ via uPA levels. In conclusion we report that in the testis HGF regulates Sertoli–Sertoli tight junctions inducing a reduction and redistribution of occludin possibly modulating the levels of uPA and active TGFβ. J. Cell. Physiol. 216: 253–260, 2008. © 2008 Wiley‐Liss, Inc.
Comparison of atmospheric aqueous glycerol and steam explosion pretreatments of wheat straw for enhanced enzymatic hydrolysis
Authors: Sun Fubao , Chen Hongzhang 
Published: February 2008

AbstractBACKGROUND: The oversupply of cheap glycerol by the oleochemicals industry together with problems occurring in low‐boiling‐point organosolv pretreatments, has generated an interest in the use of glycerol in the organosolv pretreatment of lignocellulosic biomass. Atmospheric aqueous glycerol autocatalytic organosolv pretreatment (AAGAOP) is a promising strategy that can effectively enhance enzymatic hydrolysis of lignocellulosic biomass. As a cost‐effective technique, steam explosion pretreatment (SEP) is being adopted in industrial applications. Accordingly, work has been carried out to investigate how AAGAOP enhanced enzymatic hydrolysis of lignocellulosic biomass compares with the SEP method.RESULTS: Under controlled laboratory conditions, based on ≥ 90% cellulose recovery, AAGAOP removed ≥ 60% hemicellulose and ≥ 60% lignin from wheat straw while SEP led to ∼80% hemicellulose and 10% lignin removal. Enzymatic hydrolysis yields of AAGAOP and SEP reached ∼90% and ∼70%, respectively. Physical‐chemical structural characterization by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT‐IR), helped explain the above results. The two methods gave priority to dissociating the guaiacyl lignin and had a relatively small effect on syringyl units. However, AAGAOP exhibited a superior performance.CONCLUSION: The two methods enhanced the enzymatic hydrolysis of lignocellulosic biomass by removing and/or altering physical‐chemical structural impediments. The AAGAOP technique, with some special advantages, was more effective than SEP in enhancing the recovery and enzymatic digestibility of cellulose. Copyright © 2008 Society of Chemical Industry
Systematic study of β‐asarone‐rich volatile oil from Acori graminei rhizoma by off‐line supercritical CO2 extraction–gas chromatography–mass spectrometry
Authors: Dai Jian , Ha Chengyong , Shen Minmin 
Published: February 2008

AbstractSupercritical CO2 extraction (SCE) technology was used to extract a volatile oil, rich in β‐asarone, from Acori graminei rhizoma (AGR). The effect of different extraction and fractionation parameters on oil yield and selectivity towards β‐asarone was investigated by SCE using commercial AGR samples. The optimal conditions (Pe/Te = 10 MPa/45°C; Pf1/Tf1 = 8 MPa/–10°C; Pf2/Tf2 = 2 MPa/10°C) gave a good oil yield and selectivity for β‐asarone. The extracts were also analyzed by GC–MS and compared with the volatile oil obtained by hydrodistillation, in which 39 main constituents including β‐asarone were found. Different cultivated AGR samples obtained from three areas of China were evaluated in terms of their volatile oil compositions obtained by extraction of commercial AGR samples under optimal conditions; the extract of the Guangdong (GD) sample showed a high β‐asarone content.
Optimized derivatization of acidic herbicides with trimethylsilyldiazomethane for GC analysis
Authors: Ranz Andreas , Korpecka Justyna , Lankmayr Ernst 
Published: February 2008

AbstractIn the present study, the preparation of methyl esters of chlorophenoxy acids with trimethylsilyldiazomethane (TMSD) is reported. TMSD is a mild and safe alternative to the highly toxic, thermally labile, and explosive diazomethane. Due to the novelty of this method, the characteristics of the reaction were investigated and the derivatization procedure was screened for statistically significant factors. The parameters identified as influential are the amount of methanol as well as reaction time and temperature. A careful optimization by a complete factorial response surface design was carried out to generate optimal reaction conditions with respect to maximum recovery and reaction yield. Special emphasis has been given to an accurate validation of the derivatization procedure. LODs were determined between 4.1 and 8.1 ng/mL for the enriched sample and linearity was proofed for more than five orders of magnitude. The applicability of the method was demonstrated by the analyses of quality control material including sample preparation with SPE. Polar herbicides investigated in the study belong to acetic acid (2,4‐D, MCPA, and 2,4,5‐T), butanoic acid (MCPB), and propanoic acid (mecoprop). An efficient, fast, and high‐throughput method for the determination of polar herbicides including the potential for automation is proposed.
gIsolation and purification of acetylshikonin and β‐acetoxyisovalerylshikonin from cell suspension cultures of Arnebia euchroma (Royle) Johnston using rapid preparative HPLC*
Authors: Sharma Nandini , Sharma Upendra Kumar , Malik Sonia , Bhushan Shashi , Kumar Vinod , Verma Subash Chandra , Sharma Naina , Sharma Madhu , Sinha Arun Kumar 
Published: February 2008

AbstractShikonin and its derivatives are important red colored naphthoquinone pigments found in a large number of Arnebia species, including A. euchroma, that are responsible for the various pharmacological activities exhibited by the plant. The precise separation of each naphthoquinone is essential for total quality evaluation and bioactivity analysis of herbal formulations of A. euchroma. Furthermore, the overexploitation of this useful plant has resulted in species becoming endangered. With this in mind, a simple and rapid preparative scale HPLC method with single compound recovery for the isolation and purification of two shikonin derivatives (i. e. acetylshikonin, β‐acetoxyisovalerylshikonin) from cell suspension cultures of A. euchroma is presented. The compounds were separated on a C18 column within 10 min using acetonitrile/methanol (95:5) as mobile phase in isocratic mode. The isolated compounds were found to be more than 98% pure. The LOD for acetylshikonin and β‐acetoxyisovalerylshikonin was estimated at 0.063 and 0.146 μg/mL, respectively, while the LOQ was found to be 0.209 and 0.487 μg/mL, respectively. The recoveries accomplished for both the shikonin derivatives were in the range of 94.7–96.8%. The repeatability, expressed as %RSD, of acetylshikonin and β‐acetoxyisovalerylshikonin was found to be 1.74 and 1.27, respectively.
The effect of multiple language product descriptions on product evaluations
Authors: Gopinath Mahesh , Glassman Myron 
Published: February 2008

AbstractThis study investigates the influence of bilingual product packaging descriptions on product evaluation. In an experimental study, the evaluation of a product with an English‐only package is compared to the evaluation of the same product in a bilingual package. The evaluation of the product in the bilingual package is found to be significantly lower. Ethnocentrism and prejudice are investigated as possible explanations for this differential. The effect of the method of information processing used to evaluate the product (peripheral vs. central) is also explored. Both ethnocentrism and prejudice affect evaluations of a product in a bilingual package in a peripheral processing situation, but not in a central processing situation. © 2008 Wiley Periodicals, Inc.
Opinion leaders and followers: A replication and extension
Authors: Shoham Aviv , Ruvio Ayalla 
Published: February 2008

AbstractOpinion leadership has been a central construct in studies of new product diffusion models. Flynn, Goldsmith, and Eastman (1996) introduced the related concept of opinion seeking and documented its measurement properties. This replication and extension paper examines these two concepts, using their original scales and placing them in a nomological model that includes innovativeness and computer and software use as antecedents. The research model is tested empirically using a convenience sample of 123 Israeli consumers, with regression models and a multiple discriminant analysis. Innovativeness and computer usage were found to explain opinion leadership and opinion seeking. Opinion leadership and opinion seeking predicted several computer‐related outcomes. The findings can be used to identify and utilize the differing information search profiles for opinion leaders and seekers. The former use a variety of sources, such as store visits and category‐specific newspapers and magazines. In contrast, seekers rely more on expert advice from opinion leaders. © 2008 Wiley Periodicals, Inc.
Pathogenicity of LRRK2 P755L variant in Parkinson's disease
Authors: Tan Eng‐King , Lim Hui‐Qin , Yuen Yih , Zhao Yi 
Published: February 2008

AbstractA heterozygous 2264C→T variant (P755L) in LRRK2 gene has been reported to be a likely pathogenic variant among ethnic Chinese patients with Parkinson's disease (PD). In a case control study, we performed genetic analysis of the P755L variant in an independent cohort of Chinese patients with PD and controls. The P755L variant was present in 4/204 (2.0%) of PD compared with 6/235 (2.6%) of controls (odds ratio = 0.76, 95% CI 0.23, 2.6, P = 0.76). All subjects carried the heterozygous genotype. Subset analysis in the group ≥65 years of age revealed a prevalence of 2.8% in PD compared with 3.1% in controls (odds ratio = 0.92, 95% CI 022, 3.7, P = 0.9), and in the group <65 years of age showed a 0% in PD versus 2.1% in controls (P = 0.2). The phenotype of patients with PD with the P755L variant was generally similar to other patients with PD and none of the carriers reported a positive family history. The lack of functional data, absence of segregation of the variant with disease, and the presence of the variant in apparently healthy individuals suggest that P755L is possibly a rare polymorphism in the Chinese population. Further validation of our findings in other populations would be important. © 2008 Movement Disorder Society
Adult onset simple phonic tic after caudate stroke
Authors: Gomis Meritxell , Puente Victor , Pont‐Sunyer Claustre , Oliveras Carlos , Roquer Jaune 
Published: February 2008

AbstractWe describe a case of adult onset simple phonic tic after subcortical stroke involving left caudate nucleus. In the acute phase of stroke the patient presented a mild right clumsiness with complete recovery one week after onset. Within 3 weeks after stroke the patient noticed the gradual onset of involuntary simple phonic tic consisting of an “a” sound which persists. The patient did not present motor tics or the typical Tourette syndrome co‐morbidities, such as attention deficit or obsessive‐compulsive disorder. © 2008 Movement Disorder Society
A FETI‐based domain decomposition technique for time‐dependent first‐order systems based on a DAE approach
Authors: Nakshatrala K. B. , Hjelmstad K. D. , Tortorelli D. A. 
Published: February 2008

AbstractWe present a novel partitioned coupling algorithm to solve first‐order time‐dependent non‐linear problems (e.g. transient heat conduction). The spatial domain is partitioned into a set of totally disconnected subdomains. The continuity conditions at the interface are modeled using a dual Schur formulation where the Lagrange multipliers represent the interface fluxes (or the reaction forces) that are required to maintain the continuity conditions. The interface equations along with the subdomain equations lead to a system of differential algebraic equations (DAEs). For the resulting equations a numerical algorithm is developed, which includes choosing appropriate constraint stabilization techniques. The algorithm first solves for the interface Lagrange multipliers, which are subsequently used to advance the solution in the subdomains.The proposed coupling algorithm enables arbitrary numeric schemes to be coupled with different time steps (i.e. it allows subcycling) in each subdomain. This implies that existing software and numerical techniques can be used to solve each subdomain separately. The coupling algorithm can also be applied to multiple subdomains and is suitable for parallel computers. We present examples showing the feasibility of the proposed coupling algorithm. Copyright © 2008 John Wiley & Sons, Ltd.
Flame retarding polyamide 6 with melamine cyanurate and layered silicates
Authors: Zhang Jin , Lewin Menachem , Pearce Eli , Zammarano Mauro , Gilman Jeffrey W. 
Published: February 2008

AbstractThe flammability behavior of the system polyamide 6 (PA 6) + melamine cyanurate (MC) with or without organically modified layered montmorillonite (OMMT) or sodium montmorillonite (Na+MMT) was studied. The high degree of flame retardancy (FR) obtained with 13 wt% MC is maintained upon adding up to 0.2 wt% OMMT or Na+MMT. Increase mass % of OMMT is antagonistic to the MC effect. The rate of dripping decreases while the size and mass of drops in the UL‐94 tests increases with increasing wt% OMMT indicating increase in viscosity of the melt and decrease in the rate of sublimation of melamine. Addition of poly vinyl pyrrolidone (PVP) decreases the viscosity and partially restores the FR rating. Na+MMT does not increase the viscosity and the FR ratings are partially preserved. The peak of heat release rate (PHRR) in the cone calorimeter decreases with increased loading of OMMT. Addition of Na+MMT or PVP has little influence on the PHRR. The time of ignition decreases with increase in OMMT, but is not affected when Na+MMT is used. This is explained by the low thermal conductivity of the clay containing surface layer of samples during pyrolysis and combustion. Mechanistic considerations are presented. Copyright © 2008 John Wiley & Sons, Ltd.