bluuebunny/crossref_metadata_2025 huggingface dataset:
Simultaneous determination of methocarbamol and aspirin by RP‐HPLC using fluorescence detection with time programming: its application to pharmaceutical dosage form
Authors: El‐Din M Sharaf , Eid M , Zeid AM
Published: June 2012

A new simple, rapid and sensitive reversed‐phase liquid chromatographic method was developed and validated for the simultaneous determination of methocarbamol (MET) and aspirin (ASP) in their combined dosage form. The separation of these compounds was achieved within 6.0 min on a CLC Shim‐pack C8 column (250 × 4.6 mm, 5 µm particle size) using isocratic mobile phase consisting of acetonitrile and 0.02 M dihydrogenphosphate buffer (30:70, v/v) at pH = 5.0. The analysis was performed at a flow rate of 1.0 mL/min with fluorescence detection at 277/313 nm for MET and 298/410 nm for ASP using real‐time programming. The selectivity, linearity of calibration, accuracy, inter‐ and intra‐day precision and recovery were examined as parts of the method validation. The concentration–response relationship was linear over concentration ranges of 0.02‐0.20 and 0.02‐0.40 µg/mL for MET and ASP, respectively, with a limit of detection of 6 and 32 ng/mL for MET and ASP, respectively. The proposed method was successfully applied for the analysis of both MET and ASP in prepared tablets with average recoveries of 99.88 ± 0.65% for MET and 100.44 ± 0.78% for ASP. The results were favourably compared to those obtained by a reference method. Copyright © 2012 John Wiley & Sons, Ltd.
Development of a dual‐label time‐resolved fluoroimmunoassay for the detection of α‐fetoprotein and hepatitis B virus surface antigen
Authors: Lin Guan‐Feng , Liu Tian‐Cai , Zou Li‐Ping , Hou Jing‐Yuan , Wu Ying‐Song
Published: June 2012

Time‐resolved fluorometry of lanthanide chelates is one of the most useful non‐isotopic detection techniques and has been used in numerous applications in biomedical science. We developed a time‐resolved fluoroimmunoassay (TRFIA) to quantify α‐fetoprotein (AFP) and hepatitis B virus surface antigen (HBsAg) in human serum. Based on a two‐site sandwich protocol, monoclonal antibodies (McAbs) against AFP and HBsAg were co‐coated in 96 microtitration wells and tracer McAbs against HBsAg and AFP were labeled with europium (Eu) and samarium (Sm) chelates, respectively. After application of diluted serum samples, Eu3+‐ and Sm3+‐McAbs were added and fluorescence signals of Sm3+ and Eu3+ tracers were collected. Detection limits of AFP and HBsAg were 0.09 mIU/L and 0.01 µg/L, respectively. Measurement ranges of AFP‐TRFIA and HBsAg‐TRFIA were 1–1000 mIU/L and 0.2‐150 µg/L, respectively. Intra‐ and inter‐assay coefficients of variation of AFP‐TRFIA were 3.3‐4.1% and 5.7‐7.2% and for HBsAg‐TRFIA were 2.9‐3.9% and 4.9‐6.8%, respectively. Linear correlation of TRFIA and chemiluminescence immunoassay measurements resulted in a correlation coefficient of 0.9949 for AFP and 0.9940 for HBsAg. For the endurance test, Eu‐labeled McAbs were stable for at least one year at −20°C and the results of the TRFIA with the same reagents were also reproducible after one year. The availability of a highly sensitive, reliable and convenient AFP/HBsAg TRFIA will allow the quantification of both AFP and HBsAg, thereby providing diagnostic value in various clinical conditions and could be applied for clinical use. Copyright © 2012 John Wiley & Sons, Ltd.
Internal standard strategies for relative and absolute quantitation of peptides in biological matrices by liquid chromatography tandem mass spectrometry
Authors: Pailleux Floriane , Beaudry Francis
Published: June 2012

The development of LC‐MS/MS instruments and related applications improved the large‐scale analyses of proteins and peptides in complex biological mixtures. The historical factor limiting these types of studies was the lack of sensitivity and reproducibility. However, the capacity of these analyses to detect proteins and peptides was significantly enhanced to a point where they are routinely performed in specialized laboratories in support to drug development programs as well as prognostic and diagnostic investigations. The analytical strategy used in peptidomic analyses needs to minimize the fluctuation in data measurements that might mask or reduce the precision of the determinations and consequently reduce the sensitivity of the assay. Inherently, it outlines the importance of careful standardization to reduce technical and instrumental variation. Therefore, this review will focus on the strengths and the limitations of the different experimental approaches used for the integration of internal standards in peptidomic studies. This review will examine a wide variety of methods, reagents, instrumentations and data analysis tools available to design peptidomic experiments. Moreover, this review will focus on the importance of precision and accuracy in order to adequately establish analysis threshold to detect peptide expression differences. Copyright © 2012 John Wiley & Sons, Ltd.
Highly Efficient D2 Generation by Dehydrogenation of Formic Acid in D2O through H+/D+ Exchange on an Iridium Catalyst: Application to the Synthesis of Deuterated Compounds by Transfer Deuterogenation
Authors: Wang Wan‐Hui , Hull Jonathan F. , Muckerman James T. , Fujita Etsuko , Hirose Takuji , Himeda Yuichiro
Published: June 2012

Deuterated compounds have received increasing attention in both academia and industrial fields. However, preparations of these compounds are limited for both economic and practical reasons. Herein, convenient generation of deuterium gas (D2) and the preparation of deuterated compounds on a laboratory scale are demonstrated by using a half‐sandwich iridium complex with 4,4′‐dihydroxy‐2,2′‐bipyridine. The “umpolung” (i.e., reversal of polarity) of a hydrogen atom of water was achieved in consecutive reactions, that is, a cationic H+/D+ exchange reaction and anionic hydride or deuteride transfer, under mild conditions. Selective D2 evolution (purity up to 89 %) was achieved by using HCO2H as an electron source and D2O as a deuterium source; a rhodium analogue provided HD gas (98 %) under similar conditions. Furthermore, pressurized D2 (98 %) without CO gas was generated by using DCO2D in D2O in a glass autoclave. Transfer deuterogenation of ketones gave α‐deuterated alcohols with almost quantitative yields and high deuterium content by using HCO2H in D2O. Mechanistic studies show that the H+/D+ exchange reaction in the iridium hydride complex was much faster than β‐elimination and hydride (deuteride) transfer.
Enantioselective LC/ESI‐MS/MS Analysis and Pharmacokinetic and Tissue Distribution Study of (2RS)‐1‐(7‐Methoxy‐1H‐indol‐4‐yloxy)‐3‐(2‐(2‐methoxyphenoxy)ethylamino)‐propan‐2‐ol in Rats
Authors: Walczak MARIA , Szymura‐Oleksia JOANNA , Groszek GRAZYNA
Published: June 2012

A sensitive and stereospecific liquid chromatography‐tandem mass spectrometry method for the quantitative determination of TWo8 enantiomers ((2RS)‐1‐(7‐methoxy‐1H‐indol‐4‐yloxy)‐3‐(2‐(2‐methoxyphenoxy)ethylamino)‐propan‐2‐ol) was developed and validated in rat serum and some tissues. Racemic TWo8 is a new chemical entity, and it has been shown to possess pharmacological activity in vivo. The assay involved the diastereomeric derivatization of racemic TWo8 with 2,3,4,6‐tetra‐O‐acetyl‐beta‐glucopyranosyl isothiocyanate. The TWo8 diastereoisomers quantification was performed on a triple quadrupole mass spectrometer employing an electrospray ionization technique. The precursor to the product ion transition for TWo8 derivatives and for the internal standard (carbamazepine) was m/z 776.4 → 387.2 and 237.4 → 194.4, respectively. The assay was validated with a linear range of 10–2000 ng/ml of racemic TWo8. The inter‐day precisions for (−)‐(S)‐TWo8 and (+)‐(R)‐TWo8 were 2.1% to 14.9% and 1.3% to 14.8%, respectively. The inter‐day accuracy for (−)‐(S)‐TWo8 and (+)‐(R)‐TWo8 was within 86% to 114% and 91% to 114%, respectively. A pilot pharmacokinetic study of this new β‐adrenolytic compound has shown that (−)‐(S)‐TWo8 is eliminated faster than its antipode. The terminal half‐lives of (−)‐(S)‐TWo8 and (+)‐(R)‐TWo8 were 3.2 and 3.9 h, respectively. The compound distribution into different organs, evaluated in tissue homogenate samples following TWo8 intravenous administration, showed an enantioselective penetration of TWo8 enantiomers in the liver (p < 0.03), in the kidney (p < 0.001), and in the lungs (p < 0.05). The developed method using liquid chromatography‐tandem mass spectrometry method with electrospray ionization could be employed for quantitative determination of compounds with similar structure. Chirality 24:591–599, 2012. © 2012 Wiley Periodicals, Inc.
Simultaneous Emulsification and Mixing
Authors: Köhler Karsten , Schuchmann Heike Petra
Published: June 2012

Das Hochdruckhomogenisieren ist heute eine weitverbreitete Technik in der chemischen, kosmetischen oder pharmazeutischen, aber auch der Erdöl‐ und Lebensmittelindustrie. Allerdings ist diese Technik immer noch wenig verstanden. Die Folgen sind schwer steuerbare Produktqualitäten und ein unnötig hoher Energieverbrauch. Die neu entwickelte simultane Emulgier‐ und Mischtechnik (SEM‐Technik) wird vorgestellt. Mit ihr ist es möglich, ein besseres Verständnis der einzelnen Teilvorgänge beim Hochdruckhomogenisieren, wie dem Zerkleinern und dem Stabilisieren, zu gewinnen und so den Prozess zu optimieren. Dies ermöglicht die Entwicklung neuer Prozesse und Produkte und Energieersparnisse von bis zu 90 %.
Toward a modular and efficient distribution for Web service handlers
Authors: Yildiz Beytullah , Fox Geoffrey C.
Published: June 2012

Over the last few decades, distributed systems have architecturally evolved. One recent evolutionary step is SOA. The SOA model is perfectly engendered in Web services, which provide software platforms for building applications as services. Web services utilize supportive capabilities such as security, reliability, and monitoring. These capabilities are typically provisioned as handlers, which incrementally add new features. Even though handlers are very important, the method of utilization is crucial for obtaining potential benefits. Every attempt to support a service with an additional handler increases the chance of an overwhelmingly crowded handler chain. Moreover, a handler may become a bottleneck because of its comparably higher processing time. In this paper, we present the Distributed Handler Architecture to provide an efficient, scalable, and modular architecture. The performance and scalability benchmarks show that the distributed and parallel handler executions are very promising for suitable handler configurations. The paper is concluded with remarks on the fundamentals of a promising computing environment for Web service handlers. Copyright © 2012 John Wiley & Sons, Ltd.
An architecture for retrieval of animal sound recordings based on context variables
Authors: Cugler Daniel Cintra , Medeiros Claudia Bauzer , Toledo Luís Felipe
Published: June 2012

For decades, biologists around the world have recorded animal sounds. As the number of records grows, so does the difficulty to manage them, presenting challenges to save, retrieve, share, and manage sounds. These challenges are complicated by the fact that animal sound recordings have specific peculiarities, associated to the context in which the sound was recorded. For example, sounds emitted by individuals that are in groups may be different from ones emitted by isolated individuals. Although these characteristics may be relevant to biologists, they are seldom explicit in the recording metadata. This paper discusses our ongoing research on the management of sound recordings, considering factors such as environmental or social contexts, which are not treated by current systems. This work exploits retrieval based on context analysis. Query parameters include context variables that are dynamically derived using public services and ontologies associated with sound recording metadata. Part of the results have been validated through a web prototype, discussed in the text. Copyright © 2012 John Wiley & Sons, Ltd.
An efficient self‐diagnosis protocol for hierarchical wireless mesh networks
Authors: Xu Li , Ji Lei , Zhou Shu Ming
Published: June 2012

With the development of wireless mesh networks (WMNs), fault diagnosis in WMNs is becoming a very challenging task. In this paper, a two‐level scheme for fault diagnosis in WMNs is presented. We partition the network into a two‐level topology architecture where level 1 is composed of mesh clients and level 2 consists of mesh routers. A new comparison approach is introduced to diagnose the two levels. On the basis of the new comparison approach, every node in WMNs can be diagnosed either as fault‐free or faulty. Our protocol assumes that the WMN's topology may change during the testing phase and utilize the shortest path spanning tree, which is constructed along with the process of fault diagnosis, to disseminate local messages and global messages in WMNs. The proposed model is only for static fault circumstances. We provide the analysis of correctness, communication complexity, and time complexity of our protocol, and the comparison between our protocol and others through both theoretical proof and practical simulation. The analysis shows that our model has significant advantages over other existing models. Copyright © 2012 John Wiley & Sons, Ltd.
Using Premia and Nsp for constructing a risk management benchmark for testing parallel architecture
Authors: Chancelier Jean‐Philippe , Lapeyre Bernard , Lelong Jérôme
Published: June 2012

Financial institutions have massive computations to carry out overnight, which are very CPU demanding. The challenge is to price many different products on a cluster‐like architecture. We have used the Premia software to valuate the financial derivatives. In this work, we explain how Premia can be embedded into Nsp, a scientific software like MATLAB, to provide a powerful tool to valuate a whole portfolio. Finally, we have integrated an Message Passing Interface (MPI) toolbox into Nsp to enable the use of Premia to solve a bunch of pricing problems on a cluster. This unified framework can then be used to test different parallel architectures. Copyright © 2012 John Wiley & Sons, Ltd.
Strain analysis of InGaN/GaN multi quantum well LED structures
Authors: Şebnem Çetin S. , Kemal Öztürk M. , Özçelik S. , Özbay E.
Published: June 2012

Five period InGaN/GaN multi quantum well (MQW) light emitting diode (LED) structures were grown by a metalorganic chemical vapor deposition (MOCVD) system on c‐plane sapphire. The structural characteristics as a strain‐stress analysis of hexagonal epilayers MQWs were determined by using nondestructive high resolution x‐ray diffraction (HRXRD) in detail. The strain/stress analysis in AlN, GaN, and InGaN thin films with a variation of the In molar fraction in the InGaN well layers was conducted based on the precise measurement of the lattice parameters. The a‐ and c‐lattice parameters of the structures were calculated from the peak positions obtained by rocking the theta axis at the vicinity of the symmetric and asymmetric plane reflection angles, followed by the in‐plane and out‐of‐plane strains. The biaxial and hydrostatic components of the strain were extracted from the obtained a‐ and c‐direction strains values.
One‐step green synthesis by organic molten salt method and optical properties of CdS nanosheets
Authors: Zhang Jianjun
Published: June 2012

Cadmium sulfide (CdS) nanosheets were synthesized by an environment friendly, “green” organic molten salt (OMS) method at 220 °C. The as‐synthesized products were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS), respectively. The XRD results reveal that the as‐synthesized CdS nanosheets are of the hexagonal wurtzite structure and the CdS nanosheets grow along the c‐axis. The SEM results indicate that the diameters and thickness of the CdS nanosheets are about 20–40 nm and 5–10 nm, respectively. The optical properties of the CdS nanosheets were investigated by ultraviolet–visible (UV‐Vis) spectroscopy and photoluminescence (PL) spectroscopy. The ultraviolet–visible spectrum exhibits two excitonic peaks with a step‐like absorption and the photoluminescence spectrum shows a green emission peak centered at around 524 nm. A possible growth mechanism of CdS nanosheets was discussed.
Growth and dielectric properties of Ta2O5 single crystal by the floating zone method
Authors: Xu Hong , Jiang Yijian , Fan Xiujun , Wang Yue , Liu Guoqing
Published: June 2012

Large Ta2O5 single crystal with high‐dielectric permittivity was successfully grown by floating zone (FZ) method under air atmosphere. The grown crystal that has been obtained was typically about 8 mm in diameter and 90 mm in length. The crystal growth parameters were optimized. The crystal symmetry, characterized by means of X‐ray diffraction (XRD), was found to be tetragonal. The relative permittivity and loss tangent along growth and [001] direction were measured in the temperature range between ‐200 °C and 200 °C, which showed a strong dielectric anisotropy. At a frequency of 1 MHz and 20 °C, the dielectric permittivity along the growth direction and [001] direction are 81.17 and 25.04 respectively. The stabilization of high‐temperature phase can explain the dielectric enhancement.
Metabolic studies of 1‐testosterone in horses
Authors: Kwok W. H. , Ho Emmie N. M. , Leung Gary N. W. , Tang Francis P. W. , Wan Terence S. M. , Wong Henry N. C. , Yeung John H. K.
Published: June 2012

1‐Testosterone (17β‐hydroxy‐5α‐androst‐1‐en‐3‐one), a synthetic anabolic steroid, has been described as one of the most effective muscle‐building supplements currently on the market. It has an anabolic potency of 200 as compared to 26 for testosterone. Apart from its abuse in human sports, it can also be a doping agent in racehorses. Metabolic studies on 1‐testosterone have only been reported for human in the early seventies, whereas little is known about its metabolic fate in horses. This paper describes the studies of in vitro and in vivo metabolism of 1‐testosterone in horses, with the aim of identifying the most appropriate target metabolites to be monitored for controlling the misuse or abuse of 1‐testosterone in racehorses.

Six in vitro metabolites, namely 5α‐androst‐1‐ene‐3α,17β‐diol (T1a), 5α‐androstane‐3β,17β‐diol (T2), epiandrosterone (T3), 16,17‐dihydroxy‐5α‐androst‐1‐ene‐3‐one (T4 & T5), and 5α‐androst‐1‐ene‐3,17‐dione (T6), were identified.

For the in vivo studies, two thoroughbred geldings were each administered orally with 800 mg of 1‐testosterone by stomach tubing. The results revealed that the parent drug and eight metabolites were detected in urine. Besides the four in vitro metabolites (T1a, T2, T3, and T5), four other urinary metabolites, namely 5α‐androst‐1‐ene‐3β,17α‐diol (T1b), 5α‐androst‐1‐ene‐3β,17β‐diol (T1c), 5α‐androstane‐3α,17α‐diol (T7) and 5α‐androstane‐3β,17α‐diol (T8) were identified. This study shows that the detection of 1‐testosterone administration is best achieved by monitoring the parent drug, which could be detected for up to 30 h post‐administration. Copyright © 2012 John Wiley & Sons, Ltd.
The evolution of disease resistance and tolerance in spatially structured populations
Authors: Horns Felix , Hood Michael E.
Published: June 2012

The ubiquitous challenge from infectious disease has prompted the evolution of diverse host defenses, which can be divided into two broad classes: resistance (which limits pathogen growth and infection) and tolerance (which does not limit infection, but instead reduces or offsets its negative fitness consequences). Resistance and tolerance may provide equivalent short‐term benefits, but have fundamentally different epidemiological consequences and thus exhibit different evolutionary behaviors. We consider the evolution of resistance and tolerance in a spatially structured population using a stochastic simulation model. We show that tolerance can invade a population of susceptible individuals (i.e., neither resistant nor tolerant) with higher cost than resistance, even though they each provide equivalent direct benefits to the host, because tolerant hosts impose higher disease burden upon vulnerable competitors. However, in spatially structured settings, tolerance can invade a population of resistant hosts only with lower cost than resistance due to spatial genetic structure and the higher local incidence of disease around invading tolerant individuals. The evolution of tolerance is therefore constrained by spatial genetic structure in a manner not previously revealed by nonspatially explicit models, suggesting mechanisms that could maintain variation or limit the occurrence of tolerance relative to resistance.
Impacts of upstream drought and water withdrawals on the health and survival of downstream estuarine oyster populations
Authors: Petes Laura E. , Brown Alicia J. , Knight Carley R.
Published: June 2012

Increases in the frequency, duration, and severity of regional drought pose major threats to the health and integrity of downstream ecosystems. During 2007–2008, the U.S. southeast experienced one of the most severe droughts on record. Drought and water withdrawals in the upstream watershed led to decreased freshwater input to Apalachicola Bay, Florida, an estuary that is home to a diversity of commercially and ecologically important organisms. This study applied a combination of laboratory experiments and field observations to investigate the effects of reduced freshwater input on Apalachicola oysters. Oysters suffered significant disease‐related mortality under high‐salinity, drought conditions, particularly during the warm summer months. Mortality was size‐specific, with large oysters of commercially harvestable size being more susceptible than small oysters. A potential salinity threshold was revealed between 17 and 25 ppt, where small oysters began to suffer mortality, and large oysters exhibited an increase in mortality. These findings have important implications for watershed management, because upstream freshwater releases could be carefully timed and allocated during stressful periods of the summer to reduce disease‐related oyster mortality. Integrated, forward‐looking water management is needed, particularly under future scenarios of climate change and human population growth, to sustain the valuable ecosystem services on which humans depend.
Stereoselective Synthesis of (–)‐α‐Conhydrine and Its Pyrrolidine Analogue
Authors: Dong Guang Ri , Hong Seungmin , Kim Seung In , Kim In Su , Jung Young Hoon
Published: June 2012

The stereoselective synthesis of (–)‐α‐conhydrine and its pyrrolidine analogue was achieved from readily available D‐erythronolactone. The key step of this synthesis includes a highly regioselective and diastereoselective addition of chlorosulfonyl isocyanate to 1,2‐anti‐dibenzyl ether to afford the 1,2‐anti‐amino alcohol.
Straightforward Reductive Esterification of Carbonyl Compounds with Carboxylic Acids through Tosylhydrazone Intermediates
Authors: García‐Muñoz Angel‐Humberto , Tomás‐Gamasa María , Pérez‐Aguilar M. Carmen , Cuevas‐Yañez Erick , Valdés Carlos
Published: June 2012

The reaction of carboxylic acids with tosylhydrazones in basic media gives rise to the corresponding esters through an O–H insertion reaction in the in situ generated diazo compound. The process is operationally very simple, catalyst free, and very general with regard to the structure of both coupling partners. In particular, the esterification can be accomplished by employing tosylhydrazones derived from enolizable carbonyl compounds. Considering the ready availability of tosylhydrazones from carbonyl compounds, this reaction can be visualized as a reductive esterification of carbonyl compounds.
Urban district identity as a common ingroup identity: The different role of ingroup prototypicality for minority and majority groups
Authors: Ufkes Elze G. , Otten Sabine , Van Der Zee Karen I. , Giebels Ellen , Dovidio John F.
Published: June 2012

In this paper, we examined how identification with urban districts as a common ingroup identity and perceived ingroup prototypicality influence the attitudes of residents toward other ethnic groups in their neighborhood. The overall conclusion of two field studies (N = 214 and N = 98) is that for majority‐group members, there may be a positive relation between identification with an overarching identity and outgroup attitudes but only when they perceive their ingroup as low in prototypicality for the overarching group (Study 1 and 2). Conversely, for minority‐group members, there may be a positive relation between identification and outgroup attitudes but only when they perceive their ingroup as high in prototypicality for the overarching group (Study 2). Outgroup prototypicality did not moderate the relation between identification and outgroup attitudes. Copyright © 2012 John Wiley & Sons, Ltd.
Toxicological effect of joint cadmium selenium quantum dots and copper ion exposure on zebrafish
Authors: Zhang Wei , Sun Xue , Chen Lin , Lin Kuang-Fei , Dong Qiao-Xiang , Huang Chang-Jiang , Fu Rong-Bing , Zhu Jiang
Published: June 2012

Quantum dots (QDs) have strong adsorption capacity; therefore, their potential toxicity to aquatic organisms from the facilitated transport of other trace toxic pollutants when they coexist has received increasing interest. However, the impact of cadmium selenium (CdSe) QDs and copper ion (Cu2+) joint exposure on zebrafish (Danio rerio) embryo and larvae remains almost unknown. Therefore, the present study was performed to determine the developmental toxicities to zebrafish exposed to combined pollution with CdSe QDs (500 µg/L) and Cu2+ (0, 0.1, 1, 10, and 100 µg/L CuC12) compared with single exposure. Our findings for the first time revealed that: (1) QDs facilitated the accumulation of Cu2+ in zebrafish; (2) QDs caused higher mortality, lower hatch rate, and more malformations of the exposed zebrafish; (3) junction, bifurcation, crossing, particles, and aggregation of the exposed FLI-1 transgenic zebrafish larvae can be observed; (4) embryo cell apoptosis appeared in the head and tail region; and (5) synergistic effects played an important role during joint exposure. These observations provide a basic understanding of CdSe QDs and Cu2+ joint toxicity to aquatic organisms and suggest the need for additional research to identify the toxicological mechanism. Environ. Toxicol. Chem. 2012; 31: 2117–2123. © 2012 SETAC
The effect of nitrobenzene on antioxidative enzyme activity and DNA damage in tobacco seedling leaf cells
Authors: Si Liang , Guo Changhong , Cao Yuwei , Cong Wenwen , Yuan Zening
Published: June 2012

Nitrobenzene, although widely used in industry, is a highly toxic environmental pollutant. To evaluate the toxicity of nitrobenzene to tobacco seedlings, seedlings were exposed to varying concentrations of nitrobenzene (0–100 mg/L) for 24 h. The contents of reactive oxygen species (hydrogen peroxide [H2O2] and superoxide anion [O 2−]) and the activities of antioxidative enzymes (superoxide dismutase [SOD], guaiacol peroxidase [POD], and catalase [CAT]) were measured in leaf cells. Damage to DNA was assessed by single-cell gel electrophoresis (comet assay). Compared with the control, the contents of H2O2 increased significantly with nitrobenzene concentrations ranging from 5 to 100 mg/L. Activity of SOD was induced by 50 to 100 mg/L of nitrobenzene but not by 10 to 25 mg/L. Activity of POD was stimulated by nitrobenzene at 10 to 50 mg/L but inhibited at 100 mg/L. Activity of CAT was increased significantly only by 100 mg/L. Lipid peroxidation increased with 50 to 100 mg/L, which indicated that nitrobenzene induced oxidative stress in tobacco leaf cells. Comet assay of the leaf cells showed a significant enhancement of the head DNA (H-DNA), tail DNA (T-DNA), and olive tail moment (OTM) with increasing doses of nitrobenzene. The values of H-DNA, T-DNA, and OTM exhibited significant differences from the control when stress concentrations were higher than 10 mg/L. The results indicated that nitrobenzene caused oxidative stress, which may be one of the mechanisms through which nitrobenzene induces DNA damage. Environ. Toxicol. Chem. 2012; 31: 2078–2084. © 2012 SETAC
Developmental and polyamine metabolism alterations in Rhinella arenarum embryos exposed to the organophosphate chlorpyrifos
Authors: Sotomayor Verónica , Lascano Cecilia , de D'Angelo Ana María Pechen , Venturino Andrés
Published: June 2012

Organophosphorus pesticides (OPs) are widely applied in the Alto Valle of Río Negro and Neuquén, Argentina, due to intensive fruit growing. Amphibians are particularly sensitive to environmental pollution, and OPs may transiently accumulate in ponds and channels of the region during their reproductive season. Organophosphorus pesticide exposure may alter amphibian embryonic development and the reproductive success of autochthonous species. In the present study, embryos of the common toad Rhinella arenarum were employed to assess developmental alterations and to study polyamine metabolism, which is essential to normal growth, as a possible target underlying the effects of the OP chlorpyrifos. As the duration of chlorpyrifos exposure increased and embryonic development progressed, the median lethal concentration (LC50) values decreased, and the percentage of malformed embryos increased. Developmental arrest was also observed and several morphological alterations were recorded, such as incomplete and abnormal closure of the neural tube, dorsal curvature of the caudal fin, reduction of body size and caudal fin length, atrophy, and edema. An early decrease in ornithine decarboxylase (ODC) activity and polyamine levels was also observed in embryos exposed to chlorpyrifos. The decrease in polyamine contents in tail bud embryos might be a consequence of the reduction in ODC activity. The alteration of polyamine metabolism occurred before embryonic growth was interrupted and embryonic malformations were observed and may be useful as a biomarker in environmental studies. Environ. Toxicol. Chem. 2012; 31: 2052–2058. © 2012 SETAC
Enzymatic kinetic parameters for polyfluorinated alkyl phosphate hydrolysis by alkaline phosphatase
Authors: Jackson Derek A. , Mabury Scott A.
Published: June 2012

The hydrolysis kinetics of three polyfluorinated alkyl phosphate monoesters (monoPAPs), differing in fluorinated chain length, were measured using bovine intestinal alkaline phosphatase to catalyze the reaction. Kinetic values were also measured for analogous hydrogenated phosphate monoesters to elucidate the effects of the fluorinated chain on the rate of enzymatic hydrolysis. Michaelis constants (Km) were obtained by a competition kinetics technique in the presence of p-nitrophenyl phosphate (PNPP) using UV-vis spectroscopy. Compared with Km (PNPP), Michaelis constants for monoPAPs ranged from 0.9 to 2.1 compared with hydrogenated phosphates, which ranged from 4.0 to 13.0. Apparent bimolecular rate constants (kcat/Km) were determined by monitoring rates of product alcohol formation at low substrate concentrations using gas chromatography–mass spectrometry. The experimental values for kcat/Km averaged as 1.1 × 107 M−1s−1 for monoPAPs compared with 3.8 × 105 M−1s−1 for hexyl phosphate. This suggests that the electron-withdrawing nature of the fluorinated chain enhanced the alcohol leaving group ability. The results were used in a simple model to suggest that monoPAPs in a typical mammalian digestive tract would hydrolyze in approximately 100 s, supporting a previous study that showed its absence after a dosing study in rats. Environ. Toxicol. Chem. 2012; 31: 1966–1971. © 2012 SETAC
Dynamic relay‐location‐oriented group management in MMR WiMAX networks
Authors: Sendín‐Raña Pablo , González‐Castaño Francisco J. , Gil‐Castiñeira Felipe , Rodríguez‐Hernández Pedro S.
Published: June 2012

Multihop wireless systems outperform single‐hop ones in terms of coverage and capacity. The IEEE 802.16 standard, also known as Worldwide Interoperability for Microwave Access (WiMAX), is one of the latest broadband wireless access technologies over long distances. Mobile multihop relay (MMR) WiMAX networks introduce relay stations (RS) to improve range and performance at low cost.

Providing multimedia capabilities to groups defined by node proximity is an interesting feature in tactical communications, which MMR WiMAX networks may support. This paper presents a dynamic group management scheme at the Medium Access Control (MAC) layer based on RS position, with dynamic RS selection, suitable for military environments where communications between close nodes are prioritary. The proposal is evaluated analytically and by simulations. Copyright © 2012 John Wiley & Sons, Ltd.
Outage probability scaling laws for SISO and MIMO ad‐hoc networks
Authors: Keshavarz Hengameh , Ahmadi‐Shokouh Javad
Published: June 2012

In this paper, the outage probability scaling laws for ad‐hoc networks with an arbitrary topology is studied. In single‐input single‐output ad‐hoc networks, the outage probability is tightly bounded as the number of users goes to infinity in case that channel gains are independent and identically distributed (i.i.d.). If channel gains are not i.i.d. or calculating the distribution function is complicated because path loss, it is still possible to bound the outage probability if the distances between transmitter–receiver pairs are bounded. However, there is a gap between the upper and lower bounds. Unlike previous results, our analysis is completely general and is not limited to specific node and fading distributions. In multiple‐input multiple‐output ad‐hoc networks, the calculations are much more complicated, and it is hard to tightly bound the outage probability. For a special case of i.i.d. Gaussian channel matrices, the outage probability is asymptotically bounded in terms of Chi‐square distribution functions. Finally, as an application, the outage probability analysis is utilized to study delay scaling laws in random ad‐hoc networks. Simulation results show accuracy of this estimation for different scenarios. Copyright © 2012 John Wiley & Sons, Ltd.
Network‐wide energy efficiency in wireless networks with multiple access points
Authors: Ozel Omur , Uysal‐Biyikoglu Elif
Published: June 2012

This paper presents a distributed mechanism for improving the overall energy efficiency of a wireless network where users can control their uplink transmit power targeted to the multiple access points in the network. This mechanism lets the network achieve a trade‐off between energy efficiency and spectral efficiency through the use of suitably designed utility functions. A user's utility is a function of throughput and average transmission power. Throughput is assumed to be a sigmoidal function of signal‐to‐interference‐plus‐noise ratio. Each user, being selfish and rational, acts to maximise its utility in response to signal‐to‐interference‐plus‐noise ratio by adjusting its power. The resulting mechanism is a distributed power control scheme that can incline towards energy‐efficient or spectrally efficient operating points depending on the choice of utility function. Existence and uniqueness of Nash equilibrium points in this game are shown via convergence of the distributed power iterations. It is shown that, in the best‐response strategy, each user selects a single access point. An extension of this result for a multicarrier system is considered, and the corresponding power levels used for various priorities between energy efficiency and spectral efficiency are characterised. Finally, several numerical studies are presented to illustrate the analysis. Copyright © 2012 John Wiley & Sons, Ltd.
Bin size determination for the measurement of mean flow velocity in molecular dynamics simulations
Authors: Karimian S. M. H. , Izadi S.
Published: June 2012

Extracting macroscopic properties from molecular simulation of fluids is required in most of the molecular dynamics problems. However, methods used for this purpose, their accuracy, and their dependence on the sampling and averaging schemes are still ambiguous. Macroscopic properties at any point of a molecular domain can be extracted via sampling and averaging of molecular behavior within a control region around that point, called a bin. The size of this bin has a significant impact on the accuracy of the macroscopic properties' measurement. In this research, we will focus on the measurement of mean flow velocity using ‘binning method’. On the basis of the results of this study, the most appropriate range of the bin size in which mean velocity can be measured accurately is determined. Although this range is determined based on the measurement of mean flow velocity, we believe that it can be used to estimate the proper range for the measurement of other flow quantities as well. Copyright © 2012 John Wiley & Sons, Ltd.
An implicit meshless method for application in computational fluid dynamics
Authors: Kennett D. J. , Timme S. , Angulo J. , Badcock K. J.
Published: June 2012

An implicit meshless scheme is developed for solving the Euler equations, as well as the laminar and Reynolds‐averaged Navier–Stokes equations. Spatial derivatives are approximated using a least squares method on clouds of points. The system of equations is linearised, and solved implicitly using approximate, analytical Jacobian matrices and a preconditioned Krylov subspace iterative method. The details of the spatial discretisation, linear solver and construction of the Jacobian matrix are discussed; and results that demonstrate the performance of the scheme are presented for steady and unsteady two dimensional fluid flows. Copyright © 2012 John Wiley & Sons, Ltd.
Detection of EML4‐ALK fusion genes in non‐small cell lung cancer patients with clinical features associated with EGFR mutations
Authors: Shaozhang Zhou , Xiaomei Lin , Aiping Zeng , Jianbo He , Xiangqun Song , Qitao Yu
Published: June 2012

EML4‐ALK fusion genes have been recognized as novel “driver mutations” in a small subset of non‐small cell lung cancers (NSCLC). The frequency of EML4‐ALK fusions in NSCLC patients who have clinical characteristics related to EGFR mutation remains unknown. We screened 102 Chinese patients with NSCLC based on one or more of the following characteristics: female, no or light smoking history, and adenocarcinoma histology. EML4‐ALK fusion genes were identified by RT‐PCR, whereas EGFR (Exons 18–21) and KRAS (Exons 1 and 2) mutations were detected by DNA sequencing. Eight specimens (8%) were positive for EML4‐ALK fusions, with seven being Variant 1 and one Variant 2. There were 44 (43%) and 17 (16%) patients harboring EGFR and KRAS mutations, respectively. Thirty‐one (31%) cases were wild type for EML4‐ALK, EGFR, and KRAS mutations. Of the eight patients with EML4‐ALK, none had an EGFR mutation, whereas a KRAS mutation was detected in one patient. Histologically, five of the EML4‐ALK positive tumors were adenocarcinoma and two were mixed adenosquamous carcinoma; only one was a squamous carcinoma. Our data support the conclusion that the EML4‐ALK fusion gene defines a new molecular subset of NSCLC with distinct pathologic features. © 2012 Wiley Peiodicals, Inc.
Torino subsoil characterization by combining site investigations and numerical modelling / Charakterisierung des Turiner Untergrunds mithilfe von Feldstudien und numerischer Modellierungen
Authors: Barla Marco , Barla Giovanni
Published: June 2012

This paper presents the results of the studies undertaken to assess the geotechnical parameters of the Torino subsoil (Italy). The ground conditions are characterized by a sand and gravel deposit, ranging from medium to highly dense, down to a depth of 8 to 10 m, and cemented soil (in cases a conglomerate), due to calcareous deposition processes, below this depth. The random distribution of cementation in the ground is a key factor in design and construction of underground works. To assess the ground properties as a function of the cementation degree, continuum and discontinuum numerical modelling were used. These were closely linked to the results of the characterization studies carried out so far in the laboratory and in the field (monitored drilling, SPT, large diameter pits, plate loading tests).

In diesem Artikel werden die Ergebnisse mehrerer Untersuchungen der geotechnischen Parameter des Turiner Untergrunds (Italien) vorgestellt. Der Turiner Boden zeichnet sich durch eine mitteldicht‐ bis dichtgelagerte Sand‐ und Kiesablagerung aus, die in einer Tiefe von 8 bis 10 m ansteht; darunter liegt zementierter Boden (in einigen Fällen als Konglomerat), der auf Kalkablagerungsprozesse zurückzuführen ist. Die zufällige Verteilung der Bodenzementierung ist einer der wesentlichen Faktoren, die die Bemessung und die Durchführung von unterirdischen Bauvorhaben beeinflusst. Um die Charakteristika des Bodens in Abhängigkeit vom Zementierungsgrad zu untersuchen, wurden kontinuums‐ und diskontinuumsmechanische numerische Modellierungen durchgeführt. Diese Modelle stehen in direktem Zusammenhang mit den Ergebnissen von Versuchsreihen, die bis dahin im Labor und in situ ausgearbeitet wurden (Bohraufzeichnungen, SPT, großflächige Schürfe, Plattendruckversuche).
Torino Metro Line 1 south extension – modelling and settlement monitoring / Süderweiterung der Turiner Metro Linie 1 – Modellierung und Monitoring der Setzungen
Authors: Barla Marco , Barla Giovanni , Gianoglio Gianluca
Published: June 2012

The excavation of a 3.6 km long tunnel for the Torino Metro Line 1 South Extension was recently completed by a 7.8 m diameter EPB TBM. A critical section of the tunnel was near Corso Spezia, in the Lingotto area, where the main difficulties were the presence of the water table and the poor ground conditions encountered. Another concern was the effect of the excavation on two five‐storey masonry buildings adjacent to the tunnel alignment, which were constructed in 1930 and suffered severe damage during World War II. Continuous monitoring was undertaken during excavation as time dependent settlements occurred. 2D Finite Element modelling was used to simulate the excavation and its effects on the buildings. This paper describes the most significant performance monitoring data, which is compared with the results of modelling.

Kürzlich wurde der Vortrieb eines 3,6 km langen Tunnels für die Süderweiterung der Turiner Metro Linie 1 mittels einer EPB‐Tunnelbohrmaschine mit einem Durchmesser von 7,8 m abgeschlossen. Ein kritischer Abschnitt des Tunnels lag nahe dem Corso Spezia, im Lingotto Bereich. Die Hauptschwierigkeiten dort waren die Lage des Grundwasserspiegels und die schlechten angetroffenen Bodenverhältnissen. Eine weitere Sorge galt den Auswirkungen des Tunnelvortriebs auf zwei nahe der Tunneltrasse gelegene, fünfstöckige Mauerwerksgebäude, die in den 1930er Jahren erbaut wurden und bereits im zweiten Weltkrieg erhebliche Schäden erlitten hatten. Während des Vortriebs wurde daher eine kontinuierliche Überwachung der auftretenden zeitabhängigen Setzungen durchgeführt. Eine 2D Finite‐Elemente Modellierung diente der Simulation des Vortriebsvorgangs und dessen Auswirkungen auf die Gebäude. Im vorliegenden Beitrag werden die wichtigsten Daten des Monitorings dargestellt und mit den Modellierungsergebnissen verglichen.
Multiple P2Y subtypes in spinal microglia are involved in neuropathic pain after peripheral nerve injury
Authors: Kobayashi Kimiko , Yamanaka Hiroki , Yanamoto Fujio , Okubo Masamichi , Noguchi Koichi
Published: June 2012

A prominent signaling pathway in the development of neuropathic pain involves ATP acting on microglial purinergic receptors. Among the P2Y metabotropic receptors, we reported before that the P2Y12 receptor is upregulated in microglia following nerve injury and involved in the phosphorylation of p38 MAPK, and in the development of pain behavior. In this study, we examined the expression of P2Y6, P2Y13, and P2Y14 receptors in the spinal cord and whether these receptors are involved in the pathogenesis of neuropathic pain following peripheral nerve injury. We found that spared nerve injury induced a dramatic increase of not only P2Y12, but also P2Y6, 13, and 14 receptor mRNA expression in spinal microglia. The increase continued for at least 2 weeks after injury. To determine whether p38 MAPK can induce the expression of P2Y receptors, we administered intrathecally the p38 MAPK inhibitor SB203580 and found that it significantly suppressed P2Y6, P2Y13, and P2Y14 but not P2Y12 mRNAs. Intrathecal injection of the specific P2Y6 antagonist MRS2578, specific P2Y13 antagonist MRS2211 or P2Y14 antisense LNA, attenuated mechanical pain hypersensitivity. Themixture of three antagonists for P2Y6, 12, and 13 showed a longer suppressive effect on pain behavior than the individual treatments. Our data demonstrate that ATP and other nucleotides may stimulate activated microglia with the upregulation of P2Y6, P2Y12, P2Y13, and P2Y14 receptors following nerve injury and these receptors are involved in the development of neuropathic pain. © 2012 Wiley Periodicals, Inc.
CaMKII, MAPK, and CREB are coactivated in identified neurons in a neocortical circuit required for performing visual shape discriminations
Authors: Zhang Guo‐Rong , Zhao Hua , Choi Eui M. , Svestka Michael , Wang Xiaodan , Cook Robert G. , Geller Alfred I.
Published: June 2012

Current theories postulate that the essential information for specific cognitive tasks is widely dispersed in multiple forebrain areas. Nonetheless, synaptic plasticity and neural network theories hypothesize that activation of specific signaling pathways, in specific neurons, modifies synaptic strengths, thereby encoding essential information for performance in localized circuits. Consistent with these latter theories, we have shown that gene transfer of a constitutively active protein kinase C into several hundred glutamatergic and GABAergic neurons in rat postrhinal cortex enhances choice accuracy in visual shape discriminations, and the genetically‐modified circuit encodes some of the essential information for performance. However, little is known about the role of specific signaling pathways required for learning, in specific neurons within a critical circuit. Here we show that three learning‐associated signaling pathways are coactivated in the transduced neurons during both learning and performance. After gene transfer, but before learning a new discrimination, the calcium/calmodulin‐dependent protein kinase (CaMKII), MAP kinase, and CREB pathways were inactive. During learning, these three pathways were coactivated in the transduced neurons. During later performance of the discrimination, CaMKII activity declined, but MAP kinase and CREB activity persisted. Because the transduced neurons are part of a circuit that encodes essential information for performance, activation of these learning‐associated signaling pathways, in these identified neurons, is likely important for both learning and performance. © 2012 Wiley Periodicals, Inc.