bluuebunny/crossref_metadata_2025_split huggingface dataset:
A low‐complexity MSK‐based M‐ary cyclic‐shift keying transceiver for direct sequence spread spectrum system over multipath fading channels
Authors: Deng Juinn‐Horng , Chiu Yu‐Lun , Hwang Jeng‐Kuang 
Published: February 2011

AbstractIn this paper, a low‐complexity spread spectrum system with M‐ary cyclic‐shift keying (MCSK) symbol spreading is proposed. In addition, by using the minimum‐shift‐keying (MSK) as the chip‐level modulation, we obtain a high‐rate QPSK‐MCSK transceiver scheme which not only provides a constant‐envelop and continuous‐phase transmitted signal, but can also achieve a better performance than the conventional direct sequence spread spectrum (DSSS) system. At the transmitter, the data stream is first mapped into QPSK‐MCSK symbols in terms of orthogonal Gold code sequences, then followed by the cyclic prefix (CP) insertion for combating the interblock interference, and finally applying the MSK scheme to maintain the constant‐envelope property. The receiver first performs MSK demodulation, then CP removal, and finally the channel‐included MCSK despreading and symbol demapping. Furthermore, the single input single output (SISO) QPSK‐MCSK transceiver can be easily extended to the multiple input single output (MISO) case by incorporating the space–time block coding for high‐link quality. Simulation results show that the proposed SISO and MISO QPSK‐MCSK systems significantly outperform the conventional DSSS counterparts under the AWGN channel, and attain a more robust performance under the multipath fading channel. Copyright © 2011 John Wiley & Sons, Ltd.
Long‐term diabetic complications may be ameliorated by targeting Rho kinase
Authors: Zhou Hong , Li Yongjun 
Published: February 2011

AbstractThis review addresses the roles of Rho/Rho‐kinase (ROCK) pathway in the pathogenesis of diabetes complications. Diabetes can cause many serious complications and can result in physical disability or even increased mortality. However, there are not many effective ways to treat these complications. The small guanosine‐5′‐triphosphate‐binding protein Rho and its downstream target Rho‐kinase mediate important cellular functions, such as cell morphology, motility, secretion, proliferation, and gene expression. Recently, the Rho/Rho‐kinase pathway has attracted a great deal of attention in diabetes‐related research. These studies have provided evidence that the activity and gene expression of Rho‐kinase are upregulated in some tissues in animal models of type 1 or type 2 diabetes and in cell lines cultured with high concentrations of glucose. Inhibitors of Rho‐kinase could prevent or ameliorate the pathological changes in diabetic complications. The inhibitory effects of statins on the Rho/Rho‐kinase signalling pathway may also play a role in the prevention of diabetic complications. However, the precise molecular mechanism by which the Rho/Roh‐kinase pathway participates in the development or progression of diabetic complications has not been extensively investigated. This article evaluates the relationship between Rho/Roh‐kinase tivation and diabetic complications, as well as the roles of Roh‐kinase inhibitors and statins in the complications of diabetes, with the objective of providing a novel target for the treatment of long‐term diabetic complications. Copyright © 2011 John Wiley & Sons, Ltd.
Predictors of response to dipeptidyl peptidase‐4 inhibitors: evidence from randomized clinical trials
Authors: Monami Matteo , Cremasco Francesco , Lamanna Caterina , Marchionni Niccolò , Mannucci Edoardo 
Published: February 2011

AbstractAimDipeptidyl peptidase‐4 (DPP‐4) inhibitors are used in the treatment of type 2 diabetes. Available sub‐group analysis of clinical trials does not allow a clear identification of predictors of therapeutic response to these drugs. The aim of this study is the assessment of predictors of response to DPP‐4 inhibitors.Materials and methodsA meta‐analysis was performed, exploring correlation between 24‐week effects on HbA1c of maximal doses of DPP‐4 inhibitors, compared either with placebo or with other active drugs, matches to baseline characteristics of patients enrolled in 63 randomized clinical trials, either published or unpublished but disclosed on different websites were studied.ResultsDPP‐4 inhibitors significantly reduce HbA1c at 24 weeks [by 0.6 (0.5–0.7)%] when compared with placebo; no difference in HbA1c was observed in comparisons with thiazolidinediones and α‐glucosidase inhibitors, whereas sulfonylureas and metformin produced a greater reduction of HbA1c, at least in the short term. DPP‐4 inhibitors produced a smaller weight gain than thiazolidinediones, and showed a lower hypoglycaemia risk than sulfonylureas. The placebo‐subtracted effect of DPP‐4 inhibitors on HbA1c was greater in older patients and in those with lower fasting plasma glucose at baseline. Similar results were obtained in comparisons with thiazolidinediones and metformin.ConclusionsAlthough drugs for type 2 diabetes are studied in heterogeneous samples of patients, their efficacy can be predicted by some clinical parameters. DPP‐4 inhibitors appear to be more effective in older patients with mild/moderate fasting hyperglycaemia. These data could be useful for a better definition of the profile of patients who are likely to benefit most from these drugs. Copyright © 2011 John Wiley & Sons, Ltd.
Calix[4]arene with Lower‐Rim β‐Amino α,β‐Unsaturated Ketones Containing Bis‐Chelating Sites as a Highly Selective Fluorescence Turn‐On Chemosensor for Two Copper(II) Ions
Authors: Ho I‐Ting , Chu Jean‐Ho , Chung Wen‐Sheng 
Published: February 2011

AbstractWe report herein the synthesis of a fluorescence turn‐on chemosensor, 25,27‐bis{N‐[1‐(4‐{[4‐amino‐4‐(1‐naphthyl)‐2‐oxo‐3‐butenyl]oxy}phenyl)aminocarbonyl]methoxy}‐26,28‐dihydroxycalix[4]arene (3b), which is highly selective toward Cu2+. The fluorescence intensity of 3b was enhanced upon adding [Cu(ClO4)2], which reached a maximum with approximately 4 equiv. of Cu2+ but then started to decrease in intensity at higher Cu2+ concentrations. Job plot experiments revealed a 1:2 binding stoichiometry of 3b with Cu2+. Based on 1H NMR titration results, we infer that there are two possible binding sites for Cu2+ in 3b: one at the lower‐rim phenolic‐OH and amide groups, and the second at the β‐amino α,β‐unsaturated ketone groups. It is important to note that during the complexation of 3b with [Cu(ClO4)2], the Cu2+ ions were reduced to Cu+ by both the phenolic OH and the amines of the β‐amino α,β‐unsaturated ketones. Furthermore, control compounds 6 and 9b were synthesized to clarify the possible binding sites of Cu2+ in 3b. By comparing the binding constants of 3b, 6, and 9b with Cu2+, we found that 3b exhibited a positive allosteric behavior toward the coordination of two Cu2+ ions.
Potassium Fluoride Supported on Natural Nanoporous Zeolite: A New Solid Base for the Synthesis of Diaryl Ethers
Authors: Khalilzadeh Mohammad A. , Hosseini Abolfazl , Pilevar Afsaneh 
Published: February 2011

AbstractAn efficient and inexpensive synthesis of diaryl ethers has been developed. The process involves the nucleophilic aromatic substitution of electron‐deficient aryl halides and phenols and is mediated by potassium fluoride/Clinoptilolite (KF/CP) in dimethyl sulfoxide (DMSO). The approach affords good to excellent yields of the arylated products without the need for additional cation capture. The solid base is also efficient in the Ullmann ether synthesis.
Evolution and Synthetic Applications of the Heck–Matsuda Reaction: The Return of Arenediazonium Salts to Prominence
Authors: Taylor Jason G. , Moro Angélica Venturini , Correia Carlos Roque D. 
Published: February 2011

AbstractThis review highlights the potential and the versatility of arenediazonium salts as viable alternatives to conventional aryl halides and oxygen‐based electrophiles for Pd‐catalyzed Heck reactions. It also presents an overview of the field over the last decade, including some historical perspective of the Heck–Matsuda (HM) reaction with general considerations regarding reaction conditions, type of catalysts used, and the application of arenediazonium salts as reagents for the HM arylation of several types of alkenes. Throughout this review, the principal aspects related to reactivity and selectivity are discussed, and when applicable a comparison is made between the HM and the conventional Heck reactions. One‐pot procedures that involve generation of the arenediazonium salt in situ from the corresponding aniline have been presented as well as some useful heterogeneous catalytic protocols. Allylic alcohols, conjugated alkenes, unsaturated heterocycles, and unactivated alkenes are capable of being arylated with arenediazonium salts by using simple catalysts such as Pd(OAc)2 or Pd2(dba)3 at room temperature in air and in benign and conventional solvents. In addition to the intramolecular variant of the HM reaction, intermolecular tandem coupling–cyclization processes have also been developed for the construction of a range of oxygen and nitrogen heterocycles. Finally, several applications towards the total synthesis of biologically active natural and nonnatural compounds are highlighted as well as the use of the HM reaction in the synthesis of new chiral, nonracemic ligands.
Effect of humic substances on toxicity of inorganic oxidizer bioluminescent monitoring
Authors: Tarasova Anna S , Stom Devard I , Kudryasheva Nadezhda S 
Published: February 2011

Abstract
The current study deals with the effect of humic substances (HS) on toxicity of solutions of a model inorganic oxidizer, potassium ferricyanide. Chemical reactions responsible for toxicity changes are under consideration. The bioluminescent system of coupled enzymatic reactions catalyzed by bacterial luciferase and oxidoreductase was used as a bioassay. General and oxidative toxicity of ferricyanide solutions were evaluated. Ability of HS to decrease or increase general and oxidative toxicity of the solutions was revealed. Two types of chemical processes are supposed to be responsible for detoxification by HS: ferricyanide–HS complex formation and acceleration of endogenous redox reactions in the bioluminescent assay system. Decrease of oxidative toxicity of ferricyanide solution was observed under incubation with HS at all concentrations of HS used. Conditions for general toxicity decrease were prior incubation of ferricyanide with HS and low HS concentrations (&lt;10−4 g/L). Acceleration of NADH auto-oxidation under higher HS concentrations was supposed to result in a toxicity increase. Environ. Toxicol. Chem. 2011; 30:1013–1017. © 2011 SETAC
Paper‐Fibres Used as a Pore‐Former for Anode Substrate of Solid Oxide Fuel Cell
Authors: Pan W.‐P. , Lü Z. , Chen K.‐F. , Zhu X.‐B. , Huang X.‐Q. , Zhang Y.‐H. , Wei B. , Su W.‐H. 
Published: February 2011

AbstractPaper‐fibres are studied for use as a pore‐former to produce gas channels in the anode substrates of solid oxide fuel cells (SOFCs). These fibres produce cylindrical pores within the anode substrate, which are different from the pores formed by the conventional pore‐formers such as wheat flour and graphite. The cylindrical pores make it easier to connect each other to form continuous pathways for rapid gas diffusion. Paper‐fibres can create more open porosity than the same amount of flour. The application of the paper‐fibres significantly improves the cell performance by enhancing the gas diffusion process. The anode‐supported YSZ film cells with 5 wt.‐% and 10 wt.‐% paper‐fibres exhibit maximum power densities of 0.72 and 1.06 W cm–2, respectively, using hydrogen as fuel and ambient air as oxidant at 800 °C.
Effect of pH Value and Temperatures on Performances of Pd/C Catalysts Prepared by Modified Polyol Process for Formic Acid Electrooxidation
Authors: Wang Z.‐B. , Yuan G.‐H. , Zhou K. , Chu Y.‐Y. , Chen M. 
Published: February 2011

AbstractThe highly active Pd/C catalysts for formic acid electrooxidation have been prepared by a modified polyol process at different pH values of reaction solutions and different reducing temperatures, respectively. Their physical properties have been characterised by energy dispersive analysis of X‐ray, X‐ray diffraction and transmission electron microscopy. Their electrochemical performances for formic acid electrooxidation have been tested by cyclic voltammetry and amperometric i–t curves. The results of physical characterisations show that all the Pd/C catalysts present an excellent face centered cubic crystalline structure. Their particle sizes are decreasing firstly and then increasing with the increasing of the pH values of reaction solutions. The reducing temperatures also markedly affect the Pd particle sizes. And their nanoparticles have narrow size distributions and are highly dispersed on the surface of carbon support, and Pd metal loading in Pd/C catalyst is similar to the theoretical value of 20 wt.%. The results of electrochemical measurements present that the Pd/C catalyst prepared by waterless polyol process at the pH value of 10 and the reducing temperature of 120 °C has the smallest particle size of about 5.6 nm, and exhibits the highest catalytic activity (1172.0 A · gPd<?h‐2.85>–1<?h.8>) and stability for formic acid electrooxidation.
Speculation and hedging in the currency futures markets: Are they informative to the spot exchange rates
Authors: Tornell Aaron , Yuan Chunming 
Published: February 2011

AbstractThis study presents an empirical analysis investigating the relationship between the futures trading activities of speculators and hedgers and the potential movements of major spot exchange rates. A set of trader position measures are employed as regression predictors, including the level and change of net positions, an investor sentiment index, extremely bullish/bearish sentiments, and the peak/trough indicators. We find that the peaks and troughs of net positions are generally useful predictors to the evolution of spot exchange rates, but other trader position measures are less correlated with future market movements. In addition, speculative position measures usually forecast price‐continuations in spot rates while hedging position measures forecast price‐reversals in these markets. © 2011 Wiley Periodicals, Inc. Jrl Fut Mark
Sediment targets for informing river catchment management: international experience and prospects
Authors: Collins A. L. , Naden P. S. , Sear D. A. , Jones J. I. , Foster I. D. L. , Morrow K. 
Published: February 2011

AbstractSediment plays a pivotal role in determining the physical, chemical and biological integrity of aquatic ecosystems. A range of factors influences the impacts of sediment pressures on aquatic biota, including concentration, duration of exposure, composition and particle size. In recognition of the need to assess environmental status for sediment and mitigate excessive sediment pressures on aquatic habitats, both water column and river substrate metrics have been proposed as river sediment targets. Water column metrics include light penetration, turbidity, sediment concentration summary statistics and sediment regimes. Substrate metrics include embeddedness, the fredle index and riffle stability. Identification of meaningful numeric targets along these lines has, however, been undermined by various issues including the uncertainty associated with toxicological dose‐response profiles and the impracticalities of deploying statistically robust sampling strategies capable of supporting catchment‐scale targets. Many of the thresholds reported are based on correlative relationships that fail to capture the specific mechanisms controlling sediment impacts on aquatic habitats and are stationary in nature. Temporal windows represented by the key life stages of specific species must be given greater emphasis. Given such issues and the need to support the revision of sediment targets for river catchment management, it is proposed that greater emphasis should be placed on developing generic modelling toolkits with the functionality for coupling current or future projected sediment regimes with biological response for a range of biota. Such tools should permit the identification of river catchment‐specific targets within a national context, based on biological effect and incorporate sufficient flexibility for utilizing updated physical, chemical, biological and catchment attribute data. Confidence will continue to be required in compliance screening to ensure cost‐effective management programmes for avoiding disproportionate investment in impacted river catchments. Copyright © 2011 John Wiley & Sons, Ltd.
Temporal trend in surface water resources in Tianjin in the Haihe River Basin, China
Authors: Wu Guanghong , Chen Shuirong , Su Ruixian , Jia Meiqing , Li Wanqing 
Published: February 2011

AbstractConsidering the highly stochastic nature of the hydrological process, wavelet transform was used to analyse the characteristics, trends and causes of variations in annual run‐off (1917–2006) into Tianjin in the Haihe River Basin. Run‐off was steadily declining due to climate change and human activity and a significant decrease in run‐off along the time series was discovered around the 1960s; however, the change in precipitation was insignificant. The time series of run‐off was heavily influenced by a nonlinear feature and mainly influenced by the natural climate before the 1960s, but after the 1970s the change remained steady, with an annual run‐off that fluctuated between 0·2 and 48·4 mm and was maintained at a low level (9·3 mm). The main cause of the run‐off decline in the 1960s was that more than 1900 reservoirs with a total holding capacity of up to 83 mm were constructed in the upper and middle reaches, which controlled 85% of the total run‐off. These projects have played an active role in the reservoir action and water conservation since they were implemented. At the beginning of the 1980s, the demand for water resources increased with the rapid growth of the population and the large‐scale development of industry and agriculture in the Haihe River Basin, which caused a reduction in run‐off into Tianjin. Overall, the hydrological effects of water storage projects regulating river run‐off were beneficial to flood control, but might cause a serious reduction in river run‐off into Tianjin and the lower reaches of the basin. In addition, a decrease in annual precipitation and changes in temperature in Northern China have also had an adverse effect on natural run‐off, which caused a greater decline in water resources, but this did not have a powerful influence on the overall decline in the run‐off. Copyright © 2011 John Wiley & Sons, Ltd.
Submarine groundwater discharge and seawater circulation in a subterranean estuary beneath a tidal flat
Authors: Nakada Satoshi , Yasumoto Jun , Taniguchi Makoto , Ishitobi Tomonori 
Published: February 2011

AbstractA numerical simulation and stationary geophysical survey at Omaehama, Japan, described the hydrogeology in a tidal flat and adjacent sea water column. The simulation of a tidally influenced aquifer with inland fresh groundwater discharges showed three circulations in the subterranean tidal flat estuary: a small, tide‐induced recirculation (TIR) near the sloping beach, a deeper circulation (DC) across the interface between saltwater and freshwater, and a large, tidal flat‐induced circulation (TFIC) in the offshore subterranean tidal flat and slope. The horizontal distribution of the simulated submarine groundwater discharge (SGD) showed two peaks, depending on the distance from the coast along the transect line of tidal flat; the offshore peak was quantitatively consistent with the previously observed peak based on automated seepage measurements. Time‐series of the observed resistivity profiles using a marine cable (140 m) showed the structure of the fresh water/salt water interface, and indicated a salt wedge intruding from the bottom aquifer and infiltration at the surface in the beach and nearshore tidal flat. The qualitative structure of the resistivity hardly changed at each tidal stage. These results qualitatively validated the circulation patterns shown by the numerical simulation. The source of this discharging groundwater in the tidal flat is a complex mixture of fresh groundwater derived from the landward aquifer, as well as locally recycled seawater, which can contribute to the purification of the nearshore seawater. Copyright © 2011 John Wiley & Sons, Ltd.
Geometric and structural river channel complexity and the prediction of urban inundation
Authors: Fewtrell Timothy J. , Neal Jeffrey C. , Bates Paul D. , Harrison Peter J. 
Published: February 2011

AbstractRecent research modelling floodplain inundation processes has concentrated on issues surrounding the level of physical, topographical, and numerical solver complexity needed to represent floodplain flows adequately. However, during flooding episodes the channel typically still conveys the bulk of the flow. Despite this, the effect of channel physical processes and topographic complexity on model results has been largely unexplored. To address this, the impact of channel cross‐section geometry, channel long‐profile variability and the representation of hydraulic structures on floodplain inundation are explored using a coupled dynamic 1D‐2D hydraulic model (ESTRY‐TUFLOW) of the Carlisle floods of January 2005. These simulations are compared with those from a simplified 1D‐2D model, LISFLOOD‐FP. In this case, the simpler model is sufficient to simulate the far‐field peak flood elevations. However, comparison of channel dynamics suggests that the full shallow water approximation used by ESTRY‐TUFLOW gives a more robust performance when models calibrated on maximum floodplain water elevations are used to predict channel water levels. Examination of the response of ESTRY‐TUFLOW to variations in channel geometric complexity shows that downstream variations in the channel long profile are more important than cross‐section variability for obtaining a dataset‐independent calibration. The results show, in general, that as model physical complexity is increased, calibrated parameters become less ‘effective’, and as a consequence, the values of performance measures reduce less rapidly away from the optimum value. This means that often more physically complex models are less likely to yield different optimum parameter values when calibrated on different datasets resulting in a more robust numerical model. Lastly, the inclusion of bridge structures can simulate substantial local backwatering effects, but the variability in observed water and wrack marks is such that it is not possible to discern the effect of the bridges at this site in the post‐event observational dataset. Copyright © 2011 John Wiley & Sons, Ltd.