bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of novel surface modifying macromolecules and coagulation media on the gas permeation properties of different polymeric gas separation membranes
Authors: Savoji Houman , Rana Dipak , Matsuura Takeshi , Soltanieh Mohammad , Tabe Shahram
Published: October 2011

Integrally skinned asymmetric membranes for the separation of O2 and N2 were fabricated by the phase inversion technique from polysulfone, polyetherimide, and polyimide. Two types of surface modifying macromolecules (SMMs) including hydrophilic SMM (LSMM) and charged SMM (cSMM) were synthesized and blended with the casting solution to modify the membrane surface. The cast film was then immersed in the first coagulant alcohol (methanol, ethanol, or isopropanol) for a predetermined period, before being immersed in the second coagulant (water). The SMMs used in these experiments were laboratory synthesized by the two‐step process of polyurethane prepolymer synthesis and end capping, before being characterized by differential scanning calorimetry. Their molecular structure was determined from the molecular weight obtained by gel permeation chromatography. The membranes were characterized by contact angle measurement and O2 and N2 gas permeation performance. Attempts were made to interpret the gas permeation data by delayed demixing affected by solubility parameters of polymer, solvent, and nonsolvent. Furthermore, the permeation performance of cSMM membranes was interpreted by the solvation of the charged sulfonate groups present in cSMM. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Processing and properties of syntactic foams reinforced with carbon nanotubes
Authors: Guzman Mauricio E. , Rodriguez Alejandro J. , Minaie Bob , Violette Melanie
Published: October 2011

This article presents synthesis and mechanical characterization of carbon nanotube (CNT)‐reinforced syntactic foams. Following a dispersion approach (comprising ultrasonic, calendering, and vacuum centrifugal mixing), single‐ and multi‐walled functionalized CNTs (FCNTs) were incorporated into two foam composites containing various commercially available microballoon grades (S38HS, S60HS, and H50 from 3M). The FCNT‐reinforced composites were tested for compressive strength and apparent shear strength before and after hot/wet conditioning. The results showed that the FCNT‐reinforced composites' mechanical properties depended on the vacuum pressure used during processing. Compared with pristine and commercially available syntactic foam (EC‐3500 from 3M), the FCNT‐reinforced composites processed at high vacuum (0.2 kPa) showed significant increase in compressive strength and apparent shear strength before and after hot/wet conditioning. Dynamic mechanical analysis showed an increase of about 22°C in glass transition temperature for composites processed at high vacuum with 0.5 wt % FCNT and 45 wt % S38HS–5 wt % S60HS microballoons. Thermogravimetric analysis indicated water absorption and lower decomposition temperature for the FCNT‐reinforced composite mixed at atmospheric pressure, whereas no significant change was observed for the compound processed at high vacuum. Fracture analysis showed matrix failure for the composite processed at high vacuum and microballoon crushing for the composite mixed at atmospheric pressure. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
DMA analysis of the damping of ethylene–vinyl acetate/acrylonitrile butadiene rubber blends
Authors: Shi X. Y. , Bi W. N. , Zhao S. G.
Published: October 2011

The mechanical and damping properties of blends of ethylene–vinyl acetate rubber (VA content > 40% wt) (EVM)/acrylonitrile butadiene rubber (NBR), with 1.4 phr BIPB [bis (tert‐butyl peroxy isopropyl) benzene] as curing agent, were investigated by DMA and DSC. The effect of chlorinated polyvinyl chloride (CPVC), silica, carbon black, and phenolic resin (PF) as a substitute curing agent, on the damping and mechanical properties of EVM/NBR blends were studied. The results showed that 10 phr CPVC did not contribute to the damping of EVM700/NBR blends; Silica could dramatically improve the damping of EVM700/NBR blends because of the formation of bound rubber between EVM700/NBR and silica, which appeared as a shoulder tan δ peak between 20 and 70°C proved by DMA and DSC. This shoulder tan δ peak increased as the increase of the content of EVM in EVM/NBR blends. The tensile strength, modulus at 100% and tear strength of the blend with SiO2 increased while the elongation at break and hardness decreased comparing with the blend with CB. PF, partly replacing BIPB as the curing agent, could significantly improve the damping of EVM700/NBR to have an effective damping temperature range of over 100°C and reasonable mechanical properties. Among EVM600, EVM700, and EVM800/NBR/silica blend system, EVM800/NBR/silica blend had the best damping properties. The EVM700/NBR = 80/10 blend had a better damping property than EVM700/NBR = 70/20. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis of a novel benzoxazine‐containing benzoxazole structure and its high performance thermoset
Authors: Yang Po , Gu Yi
Published: October 2011

A novel benzoxazine containing benzoxazole structures (Boz‐BOA) was synthesized and its thermoset [P(Boz‐BOA)] was prepared. For comparison, another benzoxazine‐based 4,4′‐diamine diphenyl methane (Boz‐MDA) was also synthesized using a simplified procedure. The structure of Boz‐BOA and Boz‐MDA was confirmed by Fourier transform infrared (FTIR) and 1H‐NMR. Using FTIR and differential scanning calorimetric scans method, the curing behavior of Boz‐BOA was probed, and the structure of P(Boz‐BOA) was addressed, which was similar to that of P(Boz‐MDA). Data of dynamic mechanical analysis showed that P(Boz‐BOA) exhibited a better modulus retention at high temperature than P(Boz‐MDA), which was attributed to benzoxazole structure restricting the mobility of chains, even at high temperature. P(Boz‐BOA) also exhibited high glass transition temperature (Tg), excellent thermal stability, and low coefficient of thermal expansion value at wide temperature range. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
An Anticoagulant Activity System Using Nanoengineered Autofluorescent Heparin Nanotubes
Authors: Cui Wei , Cui Yue , Zhu Pengli , Zhao Jie , Su Ying , Yang Yang , Li Junbai
Published: October 2011

Heparin (HEP) and periodate‐oxidized heparin (O‐HEP) nanotubes were prepared by combining the template method with a layer‐by‐layer (LbL) technique. The tubular structure was obtained and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and confocal laser scanning microscopy (CLSM). O‐HEP is one of the HEP derivatives that contains anticoagulant activity and preserves its ability for other effects. Chitosan (CHI) and O‐HEP have been used to fabricate nanotubes by covalent cross‐linking Schiff base reactions. It is demonstrated that the obtained nanotubes have the significant feature of autofluorescence without the addition of any fluorescent dyes and they retain their anticoagulation activity. Compared with O‐HEP/CHI nanotubes, HEP/CHI nanotubes show high anticoagulation activity and do not have autofluorescence. Furthermore, this method could be extended to other copolysaccharide derivatives for the preparation of autofluorescent nanomaterials.
A Highly Selective Colorimetric and Fluorescent Probe for Cu2+ and Hg2+ Ions Based on a Distyryl BODIPY with Two Bis(1,2,3‐triazole)amino Receptors
Authors: Shi Wen‐Jing , Liu Jian‐Yong , Ng Dennis K. P.
Published: October 2011

A new distyryl boron dipyrromethene (BODIPY) with two bis(1,2,3‐triazole)amino substituents has been prepared by typical Knoevenagel condensation followed by click reaction. The compound selectively binds to Cu2+ and Hg2+ ions in CH3CN/H2O (1:1 v/v) to give remarkably blueshifted electronic absorption and fluorescence bands as a result of inhibition of the intramolecular charge‐transfer process upon binding to these metal ions. The color changes can be easily seen by the naked eye. The binding stoichiometry between this probe and Cu2+ ions has been determined to be 1:2 by a Job plot of the fluorescence data with a binding constant of ((6.2±0.6)×109) M−2. The corresponding value for Hg2+ ions is about sixfold smaller.
The error ellipsoid in phase space of stellar encounters and its evolution in time
Authors: Serafin R.A. , Birkenbach B.
Published: October 2011

We systematically investigate stellar encounters in their six‐dimensional phase space, including also the error ellipsoid and its evolution in time. It allows to give not only a mathematical model of stellar encounters but also an error model for this process. On that occasion we derive fundamental formulae for the positional error in ℝn: the probability of a position X falling into the error ellipsoid, the standard deviation in an arbitrary direction, and we briefly discuss the mean positional error in ℝn. The case of the close encounter of the star GL 710 (HIP 89825) is an illuminating example of applying the derived results. Moreover, we show that the error ellipsoid can also be successfully applied to approximate the confidence region (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The sunspot observations by Samuel Heinrich Schwabe
Authors: Arlt R.
Published: October 2011

A long time‐series of sunspot observations is preserved from Samuel Heinrich Schwabe who made notes and drawings of sunspots from 1825–1867. Schwabe's observing records are preserved in the manuscript archives of the Royal Astronomical Society, London. The drawings have now been digitized for future measurements of sunspot positions and sizes. The present work gives an inventory and evaluation of the images obtained from the log books of Schwabe. The total number of full‐disk drawings of the sun with spots is 8486, the number of additional verbal reports on sunspots is 3699. There are also 31 reports about possible aurorae (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Angular momentum transport by thermal emission in black hole accretion disks
Authors: Johnson J.L.
Published: October 2011

We calculate the amount of angular momentum that thermal photons carry out of a viscous black hole accretion disk, due to the strong Doppler shift imparted to them by the high orbital velocity of the radiating disk material. While thermal emission can not drive accretion on its own, we show that along with disk heating it does nonetheless result in a loss of specific angular momentum, thereby contributing to an otherwise viscosity‐driven accretion flow. In particular, we show that the fraction of the angular momentum that is lost to thermal emission at a radius r in a standard, multi‐color disk is ∼0.4rs/r, where rs is the Schwarzschild radius of the black hole. We briefly highlight the key similarties between this effect and the closely related Poynting‐Robertson effect (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Algebraic analysis of the phase‐calibration problem in the self‐calibration procedures
Authors: Lannes A. , Prieur J.‐L.
Published: October 2011

This paper presents an analysis of the phase‐calibration problem encountered in astronomy when mapping incoherent sources with aperture‐synthesis devices. More precisely, this analysis concerns the phase‐calibration operation involved in the self‐calibration procedures of phase‐closure imaging. The paper revisits and completes a previous analysis presented by Lannes in the Journal of the Optical Society of America A in 2005. It also benefits from some recent developments made for solving similar problems encountered in global navigation satellite systems. In radio‐astronomy, the related optimization problems have been stated and solved hitherto at the phasor level. We present here an analysis conducted at the phase level, from which we derive a method for diagnosing and solving the difficulties of the phasor approach. In the most general case, the techniques tobe implemented appeal to the algebraic graph theory and the algebraic number theory. The minima of the objective functionals to be minimized are identified by raising phase‐closure integer ambiguities. We also show that in some configurations, to benefit from all the available information, closure phases of order greater than three are to be introduced. In summary, this study leads to a better understanding of the difficulties related to the very principle of phase‐closure imaging. To circumvent these difficulties, we propose a strategy both simple and robust (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bottom‐up modeling and simulation of tacrolimus clearance: prospective investigation of blood cell distribution, sex and CYP3A5 expression as covariates and assessment of study power
Authors: Ohtani Hisakazu , Barter Zoe , Minematsu Tsuyoshi , Makuuchi Masatoshi , Sawada Yasufumi , Rostami‐Hodjegan Amin
Published: October 2011

The objectives were to investigate the ability of population‐based in vitro–in vivo extrapolation (IVIVE) to reproduce the influence of haematocrit on the clearance of tacrolimus, observed previously, and to assess the power of clinical studies to detect the effects of covariates on the clearance of tacrolimus.

A population‐based pharmacokinetic simulator (Simcyp) was used to simulate tacrolimus clearance from in vitro metabolism data and demographic characteristics of Japanese liver transplant patients (JLTs). The relationship between haematocrit and dose‐to‐concentration (D/C) ratio was validated using seven JLTs, whose highly variable haematocrit and D/C ratio were previously analysed. This validation was used as a surrogate for establishing ‘interindividual’ variability and to assess the power of clinical studies to discern the effect of haematocrit, sex and CYP3A5 genotype on tacrolimus clearance in a virtual JLT population.

The relationship between haematocrit and D/C ratio was reproducible by Simcyp and corresponded well to those observed in seven JLTs. The number of JLTs required to detect the influence of CYP3A5 genotype and sex were estimated to be about 50 and > 600, respectively, which was consistent with the results of previous population pharmacokinetic studies for tacrolimus.

In conclusion, population‐based IVIVE is considered to be a useful approach to assess the influence of covariates a priori before conducting clinical studies. This is also helpful with study design and assessment of the statistical power of clinical studies involving population‐based pharmacokinetics to detect the effects of covariates. Copyright © 2011 John Wiley & Sons, Ltd.
The extended ocular hypotensive effect of positive liposomal cholesterol bound timolol maleate in glaucomatous rabbits
Authors: Shafaa Medhat W. , Sabra Neveen M. , Fouad Rehab A.
Published: October 2011

Increased intraocular pressure (IOP) is a significant risk factor for the development of glaucoma. Timolol maleate is a beta‐adrenergic receptor blocking agent and it is used for the treatment of glaucoma in order to reduce the elevated IOP that is characteristic of this eye disease. Systemic toxicity from topical timolol occurs more frequently than local toxicity and can affect the pulmonary, cardiac and central nervous systems. The objective of the present study, therefore, was to formulate multilamellar vesicles (MLVs) liposomal preparations of timolol maleate using their advantage of being less toxic compared with non‐liposome‐based drugs to be applied topically and to evaluate the in vivo performance of the prepared liposomes to extend the time of reduced IOP of glaucomatous rabbit's eye measured using a standard Shiotz tonometer. The encapsulation efficiency of MLVs was measured using a spectrophotometric technique. Differential scanning calorimetry (DSC) was used to monitor the effects of timolol maleate in the absence and presence of cholesterol on liposome thermal behaviour. Positively charged MLVs of timolol in the presence of a lower amount of cholesterol (DPPC(7):Chol(2):Timolol(2):SA(1) molar ratio) were found to be superior compared with other formulations in extending the ocular hypotensive effect approximately for 1 week (160 h) which encourages its physiological effectiveness. The increase of the cholesterol molar ratio in the prepared liposomal formulations serves to decrease the permeability of the lipid bilayer that is manifested by a low rate of drug release, an increased percentage of entrapment efficiency and a consequently lower bioavailability. Copyright © 2011 John Wiley & Sons, Ltd.
Effort and Fairness in Bargaining Games
Authors: Franco‐Watkins Ana M. , Edwards Bryan D. , Acuff Roy E.
Published: October 2011

Most real‐world negotiations involving monetary transactions require exertion of effort to procure services or commodities. Economic games that require individuals to split a pot of money (windfall) measure fairness boundaries in negotiations without accounting for effort. To examine how effort affects perceptions of fairness and allocation of resources during bargaining situations, we compared windfall with business situations in three experiments designed to examine effort from several unique perspectives: (a) implied effort manipulated by game description (all experiments); (b) perceptions of effort (Experiments 2 and 3); and (c) manipulation of indirect effort (Experiment 3). A consistent pattern emerged demonstrating that earned (through effort) and windfall monetary transactions differentially influenced perceived fairness. When effort was expended, participants placed a larger monetary value on that effort and compensated themselves and others accordingly. When no effort was involved, participants relied on egalitarian fairness norms. Copyright © 2011 John Wiley & Sons, Ltd.
Multiple imputation methods for inference on cumulative incidence with missing cause of failure
Authors: Lee Minjung , Cronin Kathleen A. , Gail Mitchell H. , Dignam James J. , Feuer Eric J.
Published: October 2011

Analysis of cumulative incidence (sometimes called absolute risk or crude risk) can be difficult if the cause of failure is missing for some subjects. Assuming missingness is random conditional on the observed data, we develop asymptotic theory for multiple imputation methods to estimate cumulative incidence. Covariates affect cause‐specific hazards in our model, and we assume that separate proportional hazards models hold for each cause‐specific hazard. Simulation studies show that procedures based on asymptotic theory have near nominal operating characteristics in cohorts of 200 and 400 subjects, both for cumulative incidence and for prediction error. The methods are illustrated with data on survival after breast cancer, obtained from the National Surgical Adjuvant Breast and Bowel Project (NSABP).
Response Interruption and Differential Reinforcement of Alternative Behavior for the Treatment of Pica
Authors: Hagopian Louis P. , González Melissa L. , Rivet Tessa Taylor , Triggs Mandy , Clark Seth B.
Published: October 2011

Pica displayed by two individuals with autism was decreased by a treatment involving differential reinforcement and response interruption that altered the chain of behavior involved in pica (i.e., picking up items and placing them in the mouth). The treatment involved establishing prompts to ‘clean‐up’ as a new discriminative stimulus (SD) for picking up items from the floor; and holding potential pica items was established as an SD for discarding those items in a trash receptacle, putting them away, or using them appropriately. After demonstrating the effectiveness of the treatment in an analog setting, the treatment package was systematically generalized to community settings. Copyright © 2011 John Wiley & Sons, Ltd.
The effects of myocyte enhancer factor 2A gene on the proliferation, migration and phenotype of vascular smooth muscle cells
Authors: Zhao Wang , Zhao Shui‐ping , Peng Dao‐quan
Published: October 2011

The genetic basis for the phenotypic switching of vascular smooth muscle cells (VSMCs) is unclear in atherosclerosis. Recent studies showed that the 21‐base pair deletion mutation (Δ21) in myocyte enhancer factor 2A (MEF2A) gene could be an inherited marker for coronary artery disease. MEF2A mutation may affect the phenotypic switching of VSMCs. Human aortic VSMCs were used. Four groups of VSMCs transfected with green fluorescent protein plasmid (control group), MEF2A wild‐type (WT) plasmid (WT group), MEF2A Δ21 plasmid (Δ21 group) or MEF2A siRNA (siRNA group) were studied. The proliferation of VSMCs was determined by methylthiazolyldiphenyl‐tetrazolium bromide, and the migration of VSMCs was measured by Millicell chamber. The protein expressions of MEF2A, smooth muscle α‐actin, SM22α, osteopontin and p38 mitogen‐activated protein kinase signaling pathway were detected by Western blotting. MEF2A protein expression was knockdown by siRNA transfection. MEF2A protein was overexpressed in WT and Δ21 groups. Δ21 and siRNA groups obviously showed more proliferation (methylthiazolyldiphenyl‐tetrazolium bromide, 0.63 vs 0.66 vs 0.31, P < 0.01) and migration (52.6 vs 58.0 vs 21.2, P < 0.01) of VSMCs as compared with the WT group. In addition, the transfection of Δ21 and siRNA could induce the down‐regulation of smooth muscle α‐actin and SM22α (P < 0.01) and the up‐regulation of osteopontin (P < 0.01) in VSMCs. The phosphorylated p38 signaling pathway expression was significantly enhanced in the Δ21 and siRNA groups as compared with that of the WT group (P < 0.01). These results suggest that MEF2A dominant negative mutation and RNA silence could induce the phenotypic switching of VSMCs, leading to its increased proliferation and migration, and p38 mitogen‐activated protein kinase signaling pathway may participate in it. Copyright © 2011 John Wiley & Sons, Ltd.
Development of Dispersive Liquid–Liquid Microextraction Based on Solidification of Floating Organic Drop for the Determination of Trace Lead in Water
Authors: Zhang Jing‐Wen , Wang Yu‐Kun , Du Hai‐Ying , Du Xin , Ma Jing‐Jun , Li Jing‐Ci
Published: October 2011

A new method for determining lead (Pb) content was developed by dispersive liquid–liquid microextraction based on the solidification of floating organic droplets followed by flame atomic absorption spectrometry. Under optimum conditions, the calibration graph was linear within the Pb content range of 8.43–400 µg L−1 with a detection limit of 2.53 µg L−1. The relative standard deviation for 10 replicate measurements of 20 and 400 µg L−1 of Pb were 3.41 and 2.78%, respectively. The proposed method was assessed through the analysis of certified reference water and recovery experiments.
Signal transduction in a compliant short loop of Henle
Authors: Layton Anita T. , Pham Philip , Ryu Hwayeon
Published: October 2011

To study the transformation of fluctuations in filtration rate into tubular fluid chloride concentration oscillations alongside the macula densa, we have developed a mathematical model for tubuloglomerular feedback (TGF) signal transduction along the pars recta, the descending limb, and the thick ascending limb (TAL) of a short‐looped nephron. The model tubules are assumed to have compliant walls and, thus, a tubular radius that depends on the transmural pressure difference. Previously, it has been predicted that TGF transduction by the TAL is a generator of nonlinearities: if a sinusoidal oscillation is added to a constant TAL flow rate, then the time required for a fluid element to traverse the TAL is oscillatory in time but nonsinusoidal. The results from the new model simulations presented here predict that TGF transduction by the loop of Henle is also, in the same sense, a generator of nonlinearities. Thus, this model predicts that oscillations in tubular fluid alongside the macula densa will be nonsinusoidal and will exhibit harmonics of sinusoidal perturbations of pars recta flow. Model results also indicate that the loop acts as a low‐pass filter in the transduction of the TGF signal. Copyright © 2011 John Wiley & Sons, Ltd.
Rotational Energy Transfer of SH(X2Π, v′′=0, J′′=0.5–10.5) by Collision with Ar: Λ‐Doublet Resolved Transition Propensity
Authors: Tsai Po‐Yu , Lin King‐Chuen
Published: October 2011

The behavior of Λ‐doublet resolved rotational energy transfer (RET) by Ar collisions within the SH(X2Π, v′′=0) state is characterized. The matrix elements of terms in the interaction potential responsible for interference effects are calculated to explain the propensity rules for collision‐induced transitions within and between spin–orbit manifolds. In this manner, the physical mechanisms responsible for the F1–F1, F2–F2, and F1–F2 transitions may be reasonably identified. As collision energy increases, the propensity for collisional population of the final e or f level is replaced by the e/f‐conserving propensity. Such a change in propensity rule can be predicted in terms of energy sudden approximation at high J limit for the pure Hund’s case scheme.
On ‘a simple three‐party password‐based key exchange protocol’
Authors: Lin Ching‐Ying , Hwang Tzonelih
Published: October 2011

In 2009, Huang (Int. J. Commun. Syst., 22, 857–862) proposed a simple and efficient three‐party password‐based key exchange protocol without server's public key. This work shows that the protocol could be vulnerable to an undetectable online password guessing attack. Furthermore, an improved protocol is proposed to avoid the attack. Copyright © 2011 John Wiley & Sons, Ltd.
Performance evaluation of priority based adaptive multiguard channel call admission control for multiclass services in mobile networks
Authors: Yang Shun‐Fang , Wu Jung‐Shyr , Hwang Bor‐Jiunn
Published: October 2011

The CAC (call admission control), which can guarantee call services to meet their QoS (Quality of Service) requirements, plays a significant role in providing QoS in wireless mobile networks. In this paper, an adaptive multiguard channel scheme‐based CAC strategy is proposed to prioritize traffic types and handoff calls. The major aim of the study is to develop the analytical model of the priority traffic and handoff calls based adaptive multiguard channel scheme and examining the performance through setting the value of the adaptive ratio parameters. Our proposed scheme tries to mediate the advantages and drawbacks of the static and dynamic CAC schemes. The proposed scheme is quite different from previous studies because multithreshold values have been considered for multiclass traffic by adaption parameters, and a closed form analytical model is developed The numerical results show that this scheme can be used to keep the targeted QoS requirement by suitably setting the adaptive ratio parameters. Copyright © 2011 John Wiley & Sons, Ltd.
Process‐based proxy of oxygen stress surpasses indirect ones in predicting vegetation characteristics
Authors: Bartholomeus Ruud P. , Witte Jan‐Philip M. , van Bodegom Peter M. , van Dam Jos C. , de Becker Piet , Aerts Rien
Published: October 2011

Robust relationships among soil, water, atmosphere and plants are needed to reliably forecast the plant species composition. In this paper, we show the need for, and the application of, a process‐based relationship between soil moisture conditions and vegetation characteristics. We considered 366 groundwater‐dependent sites, where oxygen stress, caused by a surplus of soil moisture, codetermines plant performance. We compared two existing indirect proxies for the soil oxygen status – namely mean spring groundwater level (MSL) and sum exceedence value (SEV) – with our newly developed process‐based proxy, viz. root respiration stress (RS). The two indirect proxies and the process‐based proxy for oxygen stress performed equally well in describing vegetation characteristics for the Netherlands under the current climate. However, relationships based on MSL and SEV appeared to produce systematic prediction errors when applied outside their calibration range, in contrast to the relationship based on RS. Hence, the two indirect proxies cannot be used in projections, such as in predicting effects of climate change on vegetation composition, all the more because they – unlike RS – do not account for essential parameters that determine oxygen stress (e.g. temperature and extreme rainfall events in the growing season). We advocate using RS for estimating vegetation impacts in climate projections to increase the reliability and effectiveness of adaptive strategies. Copyright © 2011 John Wiley & Sons, Ltd.
Enhancement of anti‐tumor immunity through local modulation of CTLA‐4 and GITR by dendritic cells
Authors: Pruitt Scott K. , Boczkowski David , de Rosa Nicole , Haley N. Rebecca , Morse Michael A. , Tyler Douglas S. , Dannull Jens , Nair Smita
Published: October 2011

Cancer vaccines have now demonstrated clinical efficacy, but immune modulatory mechanisms that prevent autoimmunity limit their effectiveness. Systemic administration of mAbs targeting the immune modulatory receptors CTLA‐4 and glucocorticoid‐induced TNFR‐related protein (GITR) on Treg and effector T cells augments anti‐tumor immunity both experimentally and clinically, but can induce life‐threatening autoimmunity. We hypothesized that local delivery of anti‐CTLA‐4 and anti‐GITR mAbs to the sites where T cells and tumor antigen‐loaded DC vaccines interact would enhance the induction of anti‐tumor immunity while avoiding autoimmunity. To achieve this goal, DCs transfected with mRNA encoding the H and L chains of anti‐mouse CTLA‐4 and GITR mAbs were co‐administered with tumor antigen mRNA‐transfected DCs. We observed enhanced induction of anti‐tumor immunity and significantly improved survival in melanoma‐bearing mice, without signs of autoimmunity. Using in vitro assays with human DCs, we demonstrated that DCs transfected with mRNA encoding a humanized anti‐CTLA‐4 mAb and mRNA encoding a soluble human GITR‐L fusion protein enhance the induction of anti‐tumor CTLs in response to DCs transfected with mRNAs encoding either melanoma or breast cancer antigens. Based on these results, this approach of using local delivery of immune modulators to enhance vaccine‐induced immunity is currently being evaluated in a phase I clinical cancer immunotherapy trial.
BAFF‐R expression correlates with positive selection of immature B cells
Authors: Tussiwand Roxane , Rauch Melanie , Flück Lukas A. , Rolink Antonius G.
Published: October 2011

The interaction between BAFF and BAFF‐R is crucial for the development of mature B cells. Here, we report that the expression of BAFF‐R is first detectable on a fraction of mouse CD19+ CD93+ IgM+ CD23– and human CD19+ CD10+ IgM+ BM B cells. This BAFF‐R+ BM B‐cell population shows higher levels of surface IgM expression and decreased RAG‐2 transcripts than BAFF‐R– immature B cells. When cultured, mouse BAFF‐R–, but not BAFF‐R+ immature B cells spontaneously undergo B‐cell receptor editing. However, BAFF‐R+ immature B cells cultured in the presence of an anti‐κ light chain antibody are induced to undergo receptor editing. This receptor editing correlates with down‐modulation of surface BAFF‐R expression and the up‐regulation of RAG‐2 at the RNA level. B‐cell receptor (BCR) cross‐linking on splenic T1 B cells results in down‐modulation of the BAFF‐R, and receptor editing and RAG‐2 up‐regulation in a minor fraction of B cells. BCR cross‐linking on splenic T2/3 B cells results in partly down and partly up‐modulation of BAFF‐R expression and no evidence for receptor editing. Overall, our data indicate that BAFF‐R expression is tightly regulated during B‐cell development in mouse and human and its expression is correlated with positive selection.
A Coordination Chemistry Study of Solvated Thorium(IV) Ions in Two Oxygen‐Donor Solvents
Authors: Torapava Natallia , Lundberg Daniel , Persson Ingmar
Published: October 2011

The structures of the dimethyl sulfoxide (dmso) and N,N′‐dimethylpropyleneurea (dmpu) solvated thorium(IV) ions have been studied in solution by extended X‐ray absorption fine structure (EXAFS), and the structure of the solid oxonium bis[nonakis(κO‐dimethyl sulfoxide)]thorium(IV) trifluoromethanesulfonate dihydrate, (H3O)[Th((CH3)2SO)9]2(CF3SO3)9·2H2O (1) has been determined by single‐crystal X‐ray diffraction and EXAFS. Compound 1 was crystallized by evaporating a saturated dmso solution. It consists of two individual nonakis(κO‐dimethyl sulfoxide)thorium(IV) units, both of which have a tricapped trigonal prismatic configuration, as also found in nonakis(dimethyl sulfoxide)thorium(IV) perchlorate previously reported. Mean Th–O bond lengths of 2.47 and 2.43 Å are found for the two structural units, respectively, for which the differences may be explained by differences in occupancy and temperature factors. The EXAFS data of 1 revealed mean Th–O and S–O bond lengths of 2.449(3) and 1.525(3) Å, respectively, and a Th–O–S bond angle of 135.2(5)° to give a Th···S distance of 3.665(7) Å. In dmso solution, the mean Th–O and S–O bond lengths are 2.447(3) and 1.534(3) Å, respectively, the Th–O–S bond angle is 133.5(5)°, and there is a Th···S distance of 3.672(7) Å. The Th–O bond‐length distribution is somewhat asymmetric in both samples with Rmax values of 2.424 and 2.422 Å for 1 and solution, respectively. In dmpu solution, the Th–O and C–O bond lengths are 2.404(5) and 1.264(2) Å, respectively, and there is a Th–O–C angle of 157.1(5)° to give a Th···C distance of 3.594(7) Å. The observed Th–O bond length indicates strongly that thorium(IV) is eight‐coordinate in dmpu.
Design, Synthesis, Molecular Docking and Crystal Structure Prediction of New Azasugar Analogues of α‐Glucosidase Inhibitors
Authors: Pistarà Venerando , Rescifina Antonio , Punzo Francesco , Greco Graziella , Barbera Vincenzina , Corsaro Antonino
Published: October 2011

This work deals with the design and synthesis of α‐glucosidase inhibitors. In order to perform this task, a molecular docking study was carried out with the N‐terminal catalytic subunit of human maltase glucoamylase, which evidenced a partially empty, hydrophobic part of the docking pocket. As a consequence, we decided to improve the docking abilities of the known α‐glucosidase inhibitor MDL 73495 and carried out the synthesis of new N‐glycosyl‐derived analogues. The addition of a hydrophobic methyl group at C‐5′ax, the concomitant elimination of the equatorial hydroxy group, the inversion of the configuration at C‐4 in the sugar unit and the substitution of the hydroxy group at C‐6′ with an amino group led to 6′‐deoxy‐6′‐amino‐6a. This compound showed the lowest in silico binding affinity among a set of compounds, whose experimental activity has been reported. Bearing these results in mind, we synthesized 6a and 6b. Because of the lack of large amounts of products, which are necessary to perform crystallization, the crystal structures of 6a and 6b were predicted in silico. These can be considered as models for future X‐ray powder diffraction characterization of these two compounds.
Chalcogenoacetylenes Obtained by Indium(III) Catalysis: Dual Catalytic Activation of Diorgano Dichalcogenides and Csp–H Bonds
Authors: Rampon Daniel S. , Giovenardi Rodrigo , Silva Tiago L. , Rambo Raoní S. , Merlo Aloir A. , Schneider Paulo H.
Published: October 2011

A new approach for the one‐pot synthesis of alkynyl chalcogenides, exemplified mainly by selenides, was developed in which dual activation of diorgano dichalcogenides and terminal acetylenes is achieved by using an indium(III) catalyst. The method has advantages of broad substrate scope, simple operation, mild reaction conditions, and good yields. A plausible reaction mechanism is proposed.
A meta‐analysis of the effects of speakers' accents on interpersonal evaluations
Authors: Fuertes Jairo N. , Gottdiener William H. , Martin Helena , Gilbert Tracey C. , Giles Howard
Published: October 2011

This paper reports a meta‐analysis of the empirical literature on the effects of speakers' accents on interpersonal evaluations. Our review of the published literature uncovered 20 studies that have compared the effects of standard accents (i.e., the accepted accent of the majority population) versus non‐standard accents (i.e., accents that are considered foreign or spoken by minorities) on evaluations about the speakers. These 20 studies yielded 116 independent effect sizes on an array of characteristics that were selected by the original researchers. We classified each of the characteristics as belonging to one of three domains that have been traditionally discussed in this area, namely status (e.g., intelligence, social class), solidarity (trustworthiness, in‐group–out‐group member), and dynamism (level of activity and liveliness). The effect was particularly strong when American Network accented speakers were compared with non–standard‐accented speakers. These results underscore prior research showing that speakers' accents have powerful effects on how others perceive them. These and other results are discussed in the context of the literature along with implications for future research in this area. Copyright © 2011 John Wiley & Sons, Ltd.
The role of rock surface hardness and internal moisture in tafoni development in sandstone
Authors: Mol Lisa , Viles Heather A.
Published: October 2011

The development of cavernous weathering features such as tafoni remains poorly understood. In particular, the roles played by internal moisture and case hardening remain unclear. In this study, Electric Resistivity Tomography (ERT) has been used to map moisture distribution within inner walls of tafoni developed in sandstone, and an Equotip device used to measure rock surface hardness as a proxy measure of the degree of weathering and case hardening. Seven large tafoni in the Golden Gate Highlands National Park (South Africa), varying in size and degree of development have been monitored. A dynamic relationship between surface hardness, degree of weathering and internal moisture regimes has been found. We propose a new conceptual model which illustrates the complex interaction between case hardening and internal moisture and suggests a new direction for cavernous weathering research. Copyright © 2011 John Wiley & Sons, Ltd.
Transient CO2 leakage and injection in wellbore‐reservoir systems for geologic carbon sequestration
Authors: Pan Lehua , Oldenburg Curtis M. , Pruess Karsten , Wu Yu‐Shu
Published: October 2011

At its most basic level, the injection of CO2 into deep reservoirs for geologic carbon sequestration (GCS) involves a system comprising the wellbore and the target reservoir, the wellbore being the only conduit available to emplace the CO2. Wellbores in general have also been identified as the most likely conduit for CO2 and brine leakage from GCS sites, especially those in sedimentary basins with historical hydrocarbon production. We have developed a coupled wellbore and reservoir model for simulating the dynamics of CO2 injection and leakage through wellbores, and we have applied the model to situations relevant to geologic CO2 storage involving upward flow (e.g. leakage) and downward flow (injection). The new simulator integrates a wellbore‐reservoir system by assigning the wellbore and reservoir to two different sub‐domains in which flow is controlled by appropriate laws of physics. In the reservoir, we model flow using a standard multiphase Darcy flow approach. In the wellbores, we use the drift‐flux model and related conservation equations for describing transient two‐phase non‐isothermal wellbore flow of CO2‐water mixtures. Applications to leakage test problems reveal transient flows that develop into quasi‐steady states within a day if the reservoir can maintain constant conditions at the wellbore. Otherwise, the leakage dynamics could be much more complicated than the simple quasi‐steady‐state flow, especially when one of the phases flowing in from the reservoir is near its residual saturation. A test problem of injection into a depleted (low‐pressure) gas reservoir shows transient behavior out to several hundred days with sub‐critical conditions in the well disappearing after 240 days. © 2011 Society of Chemical Industry and John Wiley & Sons, Ltd
Synthesis of cyclic carbonates from CO2 and diols via electrogenerated cyanomethyl anion
Authors: Wang Huan , Wu La‐Xia , Zhao Jian‐Qing , Li Rui‐Na , Zhang Ai‐Jian , Kajiura Hisashi , Li Yong‐Ming , Lu Jia‐Xing
Published: October 2011

The electrogenerated cyanomethyl anion reacts with diols in the presence of CO2 to yield the corresponding cyclic carbonates in moderated yields. The reported methodology has been carried out under mild conditions, avoiding any addition of classical bases, catalysts. In this communication, the effects of reaction conditions – such as supporting electrolyte, cathode material, current densities, charge amount, diol concentration – have been investigated to optimize the carbonates yield. © 2011 Society of Chemical Industry and John Wiley & Sons, Ltd
Quantitative liver function tests improve the prediction of clinical outcomes in chronic hepatitis C: Results from the hepatitis C antiviral long-term treatment against cirrhosis trial
Authors: Everson Gregory T. , Shiffman Mitchell L. , Hoefs John C. , Morgan Timothy R. , Sterling Richard K. , Wagner David A. , Lauriski Shannon , Curto Teresa M. , Stoddard Anne , Wright Elizabeth C.
Published: October 2011

Risk for future clinical outcomes is proportional to the severity of liver disease in patients with chronic hepatitis C virus (HCV). We measured disease severity by quantitative liver function tests (QLFTs) to determine cutoffs for QLFTs that identified patients who were at low and high risk for a clinical outcome. Two hundred and twenty-seven participants in the Hepatitis C Antiviral Long-term Treatment Against Cirrhosis (HALT-C) Trial underwent baseline QLFTs and were followed for a median of 5.5 years for clinical outcomes. QLFTs were repeated in 196 patients at month 24 and in 165 patients at month 48. Caffeine elimination rate (kelim), antipyrine (AP) clearance (Cl), MEGX concentration, methionine breath test (MBT), galactose elimination capacity (GEC), dual cholate (CA) clearances and shunt, perfused hepatic mass (PHM), and liver and spleen volumes (by single-photon emission computed tomography) were measured. Baseline QLFTs were significantly worse (P = 0.0017 to P < 0.0001) and spleen volumes were larger (P < 0.0001) in the 54 patients who subsequently experienced clinical outcomes. QLFT cutoffs that characterized patients as “low” and “high risk” for clinical outcome yielded hazard ratios ranging from 2.21 (95% confidence interval [CI]: 1.29–3.78) for GEC to 6.52 (95% CI: 3.63–11.71) for CA clearance after oral administration (Cloral). QLFTs independently predicted outcome in models with Ishak fibrosis score, platelet count, and standard laboratory tests. In serial studies, patients with high-risk results for CA Cloral or PHM had a nearly 15-fold increase in risk for clinical outcome. Less than 5% of patients with “low risk” QLFTs experienced a clinical outcome. Conclusion: QLFTs independently predict risk for future clinical outcomes. By improving risk assessment, QLFTs could enhance the noninvasive monitoring, counseling, and management of patients with chronic HCV. (Hepatology 2012)
Receptor activator of nuclear factor-κB ligand (RANKL) protects against hepatic ischemia/reperfusion injury in mice
Authors: Sakai Nozomu , Van Sweringen Heather L. , Schuster Rebecca , Blanchard John , Burns Justin M. , Tevar Amit D. , Edwards Michael J. , Lentsch Alex B.
Published: October 2011

The transcription factor nuclear factor kappaB (NF-κB) plays diverse roles in the acute injury response to hepatic ischemia/reperfusion (I/R). Activation of NF-κB in Kupffer cells promotes inflammation through cytokine expression, whereas activation in hepatocytes may be cell protective. The interaction of receptor activator of NF-κB (RANK) and its ligand (RANKL) promotes NF-κB activation; however, this ligand-receptor system has not been studied in acute liver injury. In the current study, we sought to determine if RANK and RANKL were important in the hepatic response to I/R. Mice were subjected to partial hepatic ischemia followed by reperfusion. In some experiments, mice received recombinant RANKL or neutralizing antibodies to RANKL 1 hour prior to surgery or at reperfusion to assess the role of RANK/RANKL signaling during I/R injury. RANK was constitutively expressed in the liver and was not altered by I/R. RANK was strongly expressed in hepatocytes and very weakly expressed in Kupffer cells. Serum RANKL concentrations increased after I/R and peaked 4 hours after reperfusion. Serum levels of osteoprotegerin (OPG), a decoy receptor for RANKL, steadily increased over the 8-hour period of reperfusion. Treatment with RANKL, before ischemia or at reperfusion, increased hepatocyte NF-κB activation and significantly reduced liver injury. These beneficial effects occurred without any effect on cytokine expression or liver inflammation. Treatment with anti-RANKL antibodies had no effect on liver I/R injury.

Conclusion :

During the course of injury, endogenous OPG appears to suppress the effects of RANKL. However, exogenous administration of RANKL, given either prophylactically or postinjury, reduces liver injury in a manner associated with increased hepatocyte NF-κB activation. The data suggest that RANK/RANKL may be a viable therapeutic target in acute liver injury.
Human liver cell spheroids in extended perfusion bioreactor culture for repeated-dose drug testing
Authors: Tostões Rui M. , Leite Sofia B. , Serra Margarida , Jensen Janne , Björquist Petter , Carrondo Manuel J. T. , Brito Catarina , Alves Paula M.
Published: October 2011

Primary cultures of human hepatocyte spheroids are a promising in vitro model for long-term studies of hepatic metabolism and cytotoxicity. The lack of robust methodologies to culture cell spheroids, as well as a poor characterization of human hepatocyte spheroid architecture and liver-specific functionality, have hampered a widespread adoption of this three-dimensional culture format. In this work, an automated perfusion bioreactor was used to obtain and maintain human hepatocyte spheroids. These spheroids were cultured for 3–4 weeks in serum-free conditions, sustaining their phase I enzyme expression and permitting repeated induction during long culture times; rate of albumin and urea synthesis, as well as phase I and II drug-metabolizing enzyme gene expression and activity of spheroid hepatocyte cultures, presented reproducible profiles, despite basal interdonor variability (n = 3 donors). Immunofluorescence microscopy of human hepatocyte spheroids after 3–4 weeks of long-term culture confirmed the presence of the liver-specific markers, hepatocyte nuclear factor 4α, albumin, cytokeratin 18, and cytochrome P450 3A. Moreover, immunostaining of the atypical protein kinase C apical marker, as well as the excretion of a fluorescent dye, evidenced that these spheroids spontaneously assemble a functional bile canaliculi network, extending from the surface to the interior of the spheroids, after 3–4 weeks of culture. Conclusion: Perfusion bioreactor cultures of primary human hepatocyte spheroids maintain a liver-specific activity and architecture and are thus suitable for drug testing in a long-term, repeated-dose format. (Hepatology 2012)