bluuebunny/crossref_metadata_2025 huggingface dataset:
Stimuli‐Responsive Biointerface Based on Polymer Brushes for Glucose Detection
Authors: Crulhas Bruno P. , Sempionatto Juliane R. , Cabral Murilo F. , Minko Sergiy , Pedrosa Valber A.
Published: March 2014

The construction and characterization of a biosensor based on polymer brushes is reported. The use of polymer brushes combined with nanoparticles was applied to show its suitability as a biosensor platform – with glucose oxidase as an enzyme probe. The biosensor demonstrated a pH‐sensitive on‐off property, and it was further used to control or modulate the electrochemical responses. In terms of the kinetic behavior, we were able to show the changing in the kinetic parameters of glucose oxidase operating in “on” and “off” state of the polymer brushes. The performance of the bioelectrode was investigated by chronoamperometry, impedance electrochemistry and cyclic voltammetric techniques. At optimized experimental conditions the dynamic concentration range was 2.0 to 16.0 mmol L−1 with a detection limit of 5.6×10–6 mol L−1. The repeatability of current responses for injections of 5.0 mmol L−1 glucose was evaluated to be 5.3 % (n=10). The resulting biosensor seemed to provide the enzymes with a biocompatible nanoenvironment as it sustained the enhanced enzyme activity for an extended time and promoted possible good electron transfer through the polymer brushes to the electrode.
Combination of dynamic pH junction with capillary electrophoresis‐mass spectrometry for the determination of systemins in plant samples
Authors: Bai Yu , Chang Cuilan , Du Fuyou , Tan Zhijing , Bai Yu , Liu Huwei
Published: March 2014

Systemin is an important group of plant peptide hormones participating in the regulation of plant defensive responses. An improved method, based on dynamic pH junction and capillary electrophoresis‐quadrupole time‐of‐flight mass spectrometry, was developed for online enrichment and sensitive determination of trace systemins in plants. After optimization, the online enrichment factors for six target systemins ranged from 90‐ to 127‐fold. The detection limits reached lower than 0.5 nM, which were comparable with the sensitivity of LC‐MS method. Satisfactory quantitative results were obtained in terms of linearity (R2 ≥ 0.993), dynamic range (3–120 ng/mL), and reproducibility (≤6.7%). For the analysis of real plant samples, a rapid sample preparation method was developed, using two steps of SPE purification with different retention and separation mechanisms. Finally, this method realized the successful detection of tomato systemin and tobacco hydroxyproline‐rich systemin I from plant leaves with shorter analysis time.
Prediction of partition coefficients for complex environmental contaminants: Validation of COSMOtherm, ABSOLV, and SPARC
Authors: Stenzel Angelika , Goss Kai-Uwe , Endo Satoshi
Published: March 2014

Prediction of partition coefficients is essential for screening of environmentally relevant compounds. Prediction methods using only the molecular structure as input are especially useful for this purpose. In the present study, the authors validated 3 prediction method—COSMOtherm, ABSOLV, and SPARC—which are based on more mechanistic approaches than most other quantitative structure–activity relationships. Validation was based on a consistent experimental data set of up to 270 compounds, mostly pesticides and flame retardants. The validation systems included 3 gas chromatographic (GC) columns and 4 liquid/liquid systems that represent all relevant types of intermolecular interactions. Results revealed that the overall prediction accuracy of COSMOtherm and ABSOLV is comparable, whereas SPARC performance is substantially lower than the other methods. For instance, the root mean squared error for the 4 liquid/liquid partition coefficients was 0.65 log units to 0.93 log units for COSMOtherm, 0.64 log units to 0.95 log units for ABSOLV, and 1.43 to 2.85 log units for SPARC. In addition, version and parameterization influences of COSMOtherm on the prediction accuracy were determined. Environ Toxicol Chem 2014;33:1537–1543. © 2014 SETAC
An inexpensive, temporally integrated system for monitoring occurrence and biological effects of aquatic contaminants in the field
Authors: Kahl Michael D. , Villeneuve Daniel L. , Stevens Kyle , Schroeder Anthony , Makynen Elizabeth A. , LaLone Carlie A. , Jensen Kathleen M. , Hughes Meagan , Holmen Bruce A. , Eid Evan , Durhan Elizabeth J. , Cavallin Jenna E. , Berninger Jason , Ankley Gerald T.
Published: March 2014

Assessment of potential risks of complex contaminant mixtures in the environment requires integrated chemical and biological approaches. In support of the US Great Lakes Restoration Initiative, the US Environmental Protection Agency lab in Duluth, MN, is developing these types of methods for assessing possible risks of aquatic contaminants in near-shore Great Lakes (USA) sites. One component involves an exposure system for caged fathead minnow (Pimephales promelas) adults suitable for the wide range of habitat and deployment situations encountered in and around the Great Lakes. To complement the fish exposure system, the authors developed an automated device for collection of composite water samples that could be simultaneously deployed with the cages and reflect a temporally integrated exposure of the animals. The present study describes methodological details of the design, construction, and deployment of a flexible yet comparatively inexpensive (<600 USD) caged-fish/autosampler system. The utility and performance of the system were demonstrated with data collected from deployments at several Great Lakes sites. For example, over 3 field seasons, only 2 of 130 deployed cages were lost, and approximately 99% of successfully deployed adult fish were recovered after exposures of 4 d or longer. A number of molecular, biochemical, and apical endpoints were successfully measured in recovered animals, changes in which reflected known characteristics of the study sites (e.g., upregulation of hepatic genes involved in xenobiotic metabolism in fish held in the vicinity of wastewater treatment plants). The automated composite samplers proved robust with regard to successful water collection (>95% of deployed units in the latest field season), and low within- and among-unit variations were found relative to programmed collection volumes. Overall, the test system has excellent potential for integrated chemical–biological monitoring of contaminants in a variety of field settings. Environ Toxicol Chem 2014;33:1584–1595. © 2014 SETAC
Stabilized finite element formulations for liquid membranes and their application to droplet contact
Authors: Sauer Roger A.
Published: March 2014

A liquid membrane formulation is presented that is suitable to analyze liquid films and their contact behavior. The governing strong form and weak form equations are presented in the general framework of the curvilinear coordinate system that is used for the surface description of the membrane. Particular emphasis is placed on the stabilization of the in‐plane equilibrium equations, which is essential for the quasi‐static description of liquid membranes. Two new stabilization schemes are proposed that affect only the in‐plane membrane behavior while leaving the out‐of‐plane membrane behavior unaffected. Further emphasis is placed on the description of line contact needed to impose nontrivial contact angles. The proposed formulation is discretized within the finite element method considering both standard Lagrange‐based and isogeometric NURBS‐based finite elements. Computational contact algorithms are formulated both for surface and line contact. The complete linearization of the discretize formulation is given. A large range of numerical examples is presented to illustrate the different physical aspects that are captured by the proposed formulation. The examples are further used to analyze the performance of the new stabilization schemes. Copyright © 2014 John Wiley & Sons, Ltd.
Bioactive compound reveals a novel function for ribosomal protein S5 in hepatic stellate cell activation and hepatic fibrosis
Authors: Xu Wei-Heng , Hu Hong-Gang , Tian Yuan , Wang Shao-Zhan , Li Jie , Li Jian-Zhong , Deng Xing , Qian Hui , Qiu Lei , Hu Zhen-Lin , Wu Qiu-Ye , Chai Yi-Feng , Guo Cheng , Xie Wei-Fen , Zhang Jun-Ping
Published: March 2014

Liver fibrosis and its endstage, cirrhosis, represent a major public health problem worldwide. Activation of hepatic stellate cells (HSCs) is a central event in hepatic fibrosis. However, the proteins that control HSC activation are incompletely understood. Here we show that (6aS, 10S, 11aR, 11bR, 11cS)-10-methylamino-dodecahydro-3a, 7a-diaza-benzo [de]anthracene-8-thione (MASM) exhibits potent inhibitory activity against liver fibrosis in vitro and in vivo associated with the reduction of Akt phosphorylation. Furthermore, ribosomal protein S5 (RPS5) was identified as a direct target of MASM, which stabilized RPS5 in cultured HSCs and in the liver of experimental animals after dimethylnitrosamine (DMN) or bile duct ligation (BDL). Functional studies revealed that RPS5 could prevent HSC activation. RPS5 overexpression in HSCs resulted in Akt dephosphorylation at both Ser473 and Thr308, and led to subsequent dephosphorylation of GSK3β or P70S6K. Progression of DMN- and BDL-induced hepatic fibrosis was aggravated by Rps5 knockdown and alleviated by RPS5 overexpression, which correlated with the modulation of Akt phosphorylation and HSC number in the fibrotic livers. Moreover, RPS5 was substantially reduced in the transdifferentiated HSCs, experimental fibrotic livers, and human cirrhosis samples. Conclusion: These results demonstrate that RPS5 is implicated in hepatic fibrogenesis and may represent a promising target for potential therapeutic intervention in liver fibrotic diseases. (Hepatology 2014;60:648–660)
Engineering liver
Authors: Griffith Linda G. , Wells Alan , Stolz Donna B.
Published: March 2014

Interest in “engineering liver” arises from multiple communities: therapeutic replacement; mechanistic models of human processes; and drug safety and efficacy studies. An explosion of micro- and nanofabrication, biomaterials, microfluidic, and other technologies potentially affords unprecedented opportunity to create microphysiological models of the human liver, but engineering design principles for how to deploy these tools effectively toward specific applications, including how to define the essential constraints of any given application (available sources of cells, acceptable cost, and user-friendliness), are still emerging. Arguably less appreciated is the parallel growth in computational systems biology approaches toward these same problems—particularly in parsing complex disease processes from clinical material, building models of response networks, and in how to interpret the growing compendium of data on drug efficacy and toxicology in patient populations. Here, we provide insight into how the complementary paths of engineering liver—experimental and computational—are beginning to interplay toward greater illumination of human disease states and technologies for drug development. (Hepatology 2014;60:1426–1434)
MATERNAL SENSITIVITY AND LATENCY TO POSITIVE EMOTION FOLLOWING CHALLENGE: PATHWAYS THROUGH EFFORTFUL CONTROL
Authors: Conway Anne , Mcdonough Susan C. , Mackenzie Michael , Miller Alison , Dayton Carolyn , Rosenblum Katherine , Muzik Maria , Sameroff Arnold
Published: March 2014

The ability to self‐generate positive emotions is an important component of emotion regulation. In this study, we focus on children's latency to express positive emotions following challenging situations and assess whether this ability operates through early maternal sensitivity and children's effortful control. Longitudinal relations between maternal sensitivity, infant negative affect, effortful control, and latency to positive emotion following challenge were examined in 156 children who were 33 months of age. Structural equation models supported the hypothesis that maternal sensitivity during infancy predicted better effortful control and, in turn, shorter latencies to positive emotions following challenge at 33 months. Directions for future research are discussed.
Evaluation of benzothiophene carboxamides as analgesics and anti‐inflammatory agents
Authors: Pathak Chandramani , Ranjan Singh Rajiv , Yadav Saurabh , Kapoor Neha , Raina Varshiesh , Gupta Sarika , Surolia Avadhesha
Published: March 2014

Nonsteroid anti‐inflammatory drugs (NSAIDs) represent standard therapy for the alleviation of pain and inflammation. At present various classes of compounds have been reported as selective inhibitors of cyclooxygenase‐2 (COX‐2). However, they are associated with adverse side effects. To address these issues, we report here a new class of compounds that exhibit potent analgesic and anti‐inflammatory response. Substituted bromo‐benzothiophene carboxamides (4–11) were examined for their analgesic and anti‐inflammatory properties. Our findings demonstrate that newly synthesized bromo‐benzothiophene carboxamide derivatives 4, 6, and 8 attenuate nociception and inflammation at lower concentration than classical NSAIDs, such as ibuprofen. These compounds act by selectively inhibiting COX‐2 and by disrupting the prostaglandin‐E2‐dependent positive feedback of COX‐2 regulation, which was further substantiated by reduction in the levels of cytokines, chemokines, neutrophil accumulation, synthesis of prostaglandin‐E2, expression of COX‐2, and neutrophil activation at lower concentration than the classic NSAID ibuprofen. Toxicological study reveals that these compounds are well tolerated and metabolized to avoid any toxicity. Thus, these molecules represent a new class of analgesic and anti‐inflammatory agents. © 2014 IUBMB Life, 66(3):201–211, 2014
A multiple time step scheme for multiresolved models of Macromolecules
Authors: Di Pasquale Nicodemo , Gowers Richard J. , Carbone Paola
Published: March 2014

In hybrid particle models where coarse‐grained beads and atoms are used simultaneously, two clearly separate time scales are mixed. If such models are used in molecular dynamics simulations, a multiple time step (MTS) scheme can therefore be used. In this manuscript, we propose a simple MTS algorithm which approximates for a specific number of integration steps the slow coarse‐grained bead–bead interactions with a Taylor series approximation while the atom–atom ones are integrated every time step. The procedure is applied to a previously developed hybrid model of a melt of atactic polystyrene (di Pasquale, Marchisio, and Carbone, J. Chem. Phys. 2012, 137, 164111). The results show that structure, local dynamics, and free diffusion of the model are not altered by the application of the integration scheme which can confidently be used to simulate multiresolved models of polymer melts. © 2014 Wiley Periodicals, Inc.
Improvement of GC‐MS Analysis of Shahrbabak Ziziphora tenuior Essential Oil by Using Multivariate Curve Resolution Approaches
Authors: Pakniyat Ehsan , Mousavi Mehdi
Published: March 2014

Essential oil of aerial parts of Ziziphora tenuior growing in Shahrbabak in central Iran are isolated by hydrodistillation. Due to complexity of essential oils, there are fundamental problems such as co‐elution in their direct gas chromatography‐mass spectrometry analysis. These problems can result in low similarity matches in MS library search, so that true identification and determination of individual components may fail. In the present work, each component was identified and determined using GC‐MS coupled with multivariate curve resolution (MCR) techniques. In this way, more information along with higher accuracy and precision can be extracted from pure experimental GC‐MS data. The number of identified components found increased from 37 in direct similarity search to 80 in GC‐MS/MCR method. To identify each individual component, similarity search and Kovat's retention index comparison were implemented. The results found showed that pulegone (38.3%), 3′,5′‐dihydroxyacetophenone (22.83%), isomenthone (7.06%), 2‐methyl‐5‐(1‐methylethyl)‐phenol (3.41%), limonene (2.59%) and 2‐acetyl‐4,4‐dimethyl‐cyclopent‐2‐enone (2.49%) were the most abundant components. The reported compounds accounted for 94.39% of total content of the essential oil. A characteristic feature of the Iranian Ziziphora tenuior is the absence of piperitenone in its constituents compared with the oil of other Ziziphora species from Turkey.
Solvation Chemistry of DL‐Nor‐Valine in Aqueous Mixture of Dipolar Aprotic N,N‐Dimethyl Formamide
Authors: Mahali K. , Roy S. , Dolui B. K.
Published: March 2014

In this article, we reported the solubilities of the amino acid DL‐nor‐valine (VAL) at five equidistant temeratures i.e. from 15 to 35 °C in aqueous mixtures of N,N‐dimethyl formamide (DMF). The Standard free energies (ΔG (i)) and entropies (ΔS (i)) of transfer of VAL from water to aqueous mixture of cationophilic dipolar aprotic DMF have been evaluated at 25 °C. The transfer of Gibbs energies (ΔG (i)) and entropies (TΔS (i)) due to the chemical effects have been obtained after elimination of cavity effect, estimated by the scaled particle theory and dipole‐dipole interaction effects, computed by the used of Keesom‐orientation expression. The chemical contribution of transfer energetics of DL‐nor‐valine (VAL) are mainly guided by the composite effects of increased dispersion interaction, basicity effect and decreased acidity, hydrogen bonding effects, hydrophilic hydration and hydrophobic hydration of aqueous DMF mixtures as compared to that of reference solvent, water.
Nano‐composite Based on Platinum Particles and Modified Polyaniline for Methanol, Formic Acid, and Ethanol Oxidation
Authors: Kuo Chung‐Wen , Tsai Cheng‐Jang , Chen Wan‐Ping , Chen Pin‐Rong , Wu Tzi‐Yi , Tseng Ching‐Guey
Published: March 2014

Polyaniline (PANI) is doped with poly(styrenesulfonic acid) (PSS) via a doping‐dedoping‐redoping process. Fourier transform infrared (FT‐IR) spectroscopy results confirm that PANI is doped with PSS. X‐ray photoelectron spectroscopy (XPS) results indicate that the strong interaction between Pt particles and sulfonic acid groups of PANI‐PSS. Scanning electron microscopy (SEM) images reveal that PANI‐PSS is composed of highly porous nanowires. Platinum (Pt) can be deposited onto PANI‐PSS film using the potentiostatic mode to obtain PANI‐PSS‐Pt composite electrode. Transmission electron microscopy (TEM) image result indicates that Pt particles are dispersed uniformly into the electrode. The effects of concentration on electrocatalytic oxidation of ethanol, formic acid, and methanol are investigated. Cyclic voltammetry results and chronoamperometric response measurements show that the activity and stability toward methanol oxidation of the PANI‐PSS‐Pt electrode are better than those of the PANI‐PSS‐Pt electrodes toward ethanol and formic acid oxidation.
Photocatalytic degradation kinetics and mechanisms of antibacterial triclosan in aqueous TiO2 suspensions under simulated solar irradiation
Authors: Stamatis Nikolaos , Antonopoulou Maria , Hela Dimitra , Konstantinou Ioannis
Published: March 2014

BACKGROUND

The present study focuses on the photocatalytic transformation and mineralization of triclosan (TCS) using TiO2 catalyst. The main objectives were: (a) to investigate the effect of TiO2, TCS concentration and irradiation intensity on the photocatalytic efficiency and to model the degradation and mineralization percentage of TCS using response surface methodology (RSM) based on central composite design (CCD); (b) to identify transformation products (TPs) and degradation mechanisms, (c) to assess the toxicity of the TPs.

RESULTS

The results from the RSM analysis indicated that all operating parameters studied have significant effects on TCS degradation and mineralization. A quadratic response surface model was found to fit the experimental data and was used to find the optimum experimental conditions. Scavenging experiments indicated that HO• radicals were principally responsible for TCS degradation. The transformation of TCS involved reactions of mono‐ and di‐ hydroxylation, dechlorination, and cleavage of the ether bond. Total detoxification of the treated solution was obtained after 30 min, as revealed by Microtox bioassay.

CONCLUSION

TCS can be effectively degraded and mineralized using TiO2 under simulated solar light avoiding the formation of highly toxic TPs. RSM modeling provided a statistically accurate prediction of the optimum degradation and mineralization of TCS. © 2014 Society of Chemical Industry
Recovery of streptomycin sulfate from the wastewater using foam fractionation coupled with adsorption separation for reusing sodium dodecyl sulfate
Authors: Kou Qian‐yun , Li Juan , Zhao Bin , Wu Zhao‐liang
Published: March 2014

BACKGROUND

Surfactants are always used as collectors to form complexes with the hazardous materials of wastewaters in foam fractionation. An important topic is how to reuse the surfactants in the process of recovering the hazardous materials. In this work, a novel technology of foam fractionation coupled with adsorption separation was developed for separating streptomycin sulfate (SS) from its simulated wastewater and reusing the collector sodium dodecyl sulfate (SDS).

RESULTS

D152 resin had a high SS adsorption capacity and a low SDS adsorption capacity using adsorption separation. A high SS desorption percentage of 96.0% was obtained while SDS was not desorbed. The desorbed resin still had the same high SS adsorption capacity as a fresh one and SDS was not adsorbed. From the coupling technology, the SS recovery percentage reached as high as 94.1% which was better than foam fractionation or adsorption separation, respectively and 93.7% of SDS was reused.

CONCLUSION

It was effective for the coupling technology not only to separate SS from the wastewaters, but also to reuse SDS in foam fractionation. The coupling technology gave a novel and effective method for treating wastewaters. © 2014 Society of Chemical Industry
Multiplicative by nature: Logarithmic transformation in allometry
Authors: Packard Gary C.
Published: March 2014

The traditional allometric method, which is at the heart of research paradigms used by comparative biologists around the world, entails fitting a straight line to logarithmic transformations of the original bivariate data and then back‐transforming the resulting equation to form a two‐parameter power function in the arithmetic scale. The method has the dual advantages of enabling investigators to fit statistical models that describe multiplicative growth while simultaneously addressing the multiplicative nature of residual variation in response variables (heteroscedasticity). However, important assumptions of the traditional method seldom are assessed in contemporary practice. When the assumptions are not met, mean functions may fail to capture the dominant pattern in the original data and incorrect form for error may be imposed upon the fitted model. A worked example from metabolic allometry in doves and pigeons illustrates both the power of newer statistical procedures and limitations of the traditional allometric method. J. Exp. Zool. (Mol. Dev. Evol.) 322B: 202–207, 2014. © 2014 Wiley Periodicals, Inc.
Interdecadal modulation of ENSO teleconnections to the Indian Ocean Basin Mode and their relationship under global warming in CMIP5 models
Authors: Tao Weichen , Huang Gang , Hu Kaiming , Qu Xia , Wen Guanhuan , Gong Hainan
Published: March 2014

On the basis of Coupled Model Intercomparison Project phase 5 (CMIP5) models, this study have examined the ability of models to capture the El Niño/Southern Oscillation (ENSO)–Indian Ocean Basin Mode (IOBM) relationship, and investigated the characteristics of interdecadal change of ENSO–IOBM relationship as well as the response of the ENSO–IOBM relationship to the global warming. Among 23 CMIP5 models, the capability of models in representing the IOBM depends largely on the simulation of ENSO. Moreover, half of the models can reproduce the unstable ENSO–IOBM relationship. Considering the simulations of ENSO, ENSO–IOBM relationship and interdecadal change, 6 of 23 CMIP5 models are chosen for further investigation. The interdecadal change of ENSO–IOBM relationship is relative to the three ENSO‐related processes. During the high correlation (HC) period, the tropospheric temperature (TT) mechanism, oceanic Rossby waves and antisymmetric wind pattern are strong, prolonging the persistence of IOBM. In comparison, during the low correlation (LC) period, the three processes are weak. The results show that the shallow thermocline in the southwestern Indian Ocean (SWIO), increased interannual variability and prolonged periodicity of ENSO are all responsible for the interdecadal change.

Furthermore, the possible changes of ENSO–IOBM relationship in the future are investigated. The ENSO‐related tropical Indian Ocean (TIO) warming is strengthened under global warming. Despite the deepened thermocline over SWIO and unchanged ENSO activity, the ENSO‐related TIO warming is strengthened by the enhanced TT mechanism, which is caused by the increased saturated specific humidity. The results reveal that there is more downward net heat flux (NHF) over the TIO, which is conducive to the TIO warming, and the latent heat flux (LHF) change makes a great contribution to the NHF change. The weakened upward or strengthened downward LHF is possibly due to the decreased anomalous sea–air temperature difference by strengthened TT mechanism.
Quantitative analysis of progressive removal of nasal structures during endoscopic suprasellar approach
Authors: de Notaris Matteo , Prats‐Galino Alberto , Enseñat Joaquim , Topczewski Thomas , Ferrer Enrique , Cavallo Luigi Maria , Cappabianca Paolo , Solari Domenico
Published: March 2014

Objectives/Hypothesis

Following recent studies measuring working area and surgical freedom of transcranial approaches, we aimed to quantify the gain achieved with progressive removal of nasal structures during the endoscopic endonasal suprasellar approach.

Study Design

Human cadaveric anatomic study.

Methods

The width of the endoscopic endonasal corridor to the suprasellar area was obtained and measured in five cadaver heads using a computerized tracking system with six steps: 1) standard approach with monolateral lateralization of middle turbinate; 2) standard bilateral lateralization of the middle turbinates; 3) monolateral middle turbinectomy; 4) bilateral middle turbinectomy; 5) monolateral ethmoidectomy; 6) bilateral ethmoidectomy.

Results

The progressive removal of nasal structures offers a nonlinear increasing of the working area during the first steps of the procedure. The maximum advantage is offered by bilateral lateralization of the middle turbinates (102.7% increase in exposure), whereas a moderate increase is observed with each following step. Surgical freedom mainly increased during the first part of the approach, that is, with a monolateral right middle turbinectomy (17.9% raise of maneuverability), whereas additional steps did not increase surgical freedom enough to justify an aggressive nasal disruption.

Conclusions

Monolateral turbinectomy on the side of endoscope docking represents the best solution, optimizing working area and surgical freedom (offering increases of 116.9% and 17.9%, respectively). Bilateral turbinectomy, together with a monolateral anterior and posterior ethmoidectomy, can be reserved for selected cases (increases of 148.5% and 24.7%, respectively). Bilateral ethmoidectomy does not significantly improve surgical freedom (0.81%).

Level of Evidence

N/A. Laryngoscope 124:2231–2237, 2014
Deep‐subwavelength light confinement and transport in hybrid dielectric‐loaded metal wedges
Authors: Bian Yusheng , Gong Qihuang
Published: March 2014

The goal of confining light at the deep‐subwavelength scale while retaining moderate attenuation has been pursued for years in the field of plasmonics. However, few feasible configurations at present are excellent at balancing the tradeoff between confinement and loss. This work proposes to overcome the above limitation by using hybrid wedge structures, which consist of triangular metal wedges loaded with nanometric low/high‐index dielectric claddings. Owing to the superior guiding properties of wedge plasmons in conjunction with high refractive index contrast near wedge tips, the modal sizes can be squeezed into significantly smaller spaces than those of their conventional wedge and planar hybrid counterparts, while simultaneously featuring propagation distances over tens of micrometers at telecommunication wavelengths. Studies on the evolution from a single metallic wedge to semiconductor–insulator–metal wedge(s) reveal strategies for continuous improvement of the optical performance. Discussions concerning practical issues including crosstalk and mode excitation have further elucidated their potential in building high‐performance nanophotonic components.
Severe muscle depletion predicts postoperative length of stay but is not associated with survival after liver transplantation
Authors: Montano-Loza Aldo J. , Meza-Junco Judith , Baracos Vickie E. , Prado Carla M. M. , Ma Mang , Meeberg Glenda , Beaumont Crystal , Tandon Puneeta , Esfandiari Nina , Sawyer Michael B. , Kneteman Norman
Published: March 2014

Muscle depletion or sarcopenia is associated with increased mortality in patients with cirrhosis; how it affects mortality after liver transplantation requires further study. In this study, we aimed to establish whether sarcopenia predicts increased morbidity or mortality after liver transplantation. We analyzed 248 patients with cirrhosis who had a computed tomography (CT) scan including the third lumbar vertebra before liver transplantation. Data were recovered from medical charts, the skeletal muscle cross-sectional area was measured with CT, and sarcopenia was defined with previously published sex- and body mass index–specific cutoffs. One hundred sixty-nine patients (68%) were male, and the mean age at transplantation was 55 ± 1 years. The etiologies of cirrhosis were hepatitis C virus (51%), alcohol (19%), autoimmune liver diseases (15%), hepatitis B virus (8%), and other etiologies (7%). Sarcopenia was present in 112 patients (45%), and it was more frequent in males (P = 0.002), patients with ascites (P = 0.02), and patients with higher bilirubin levels (P = 0.05), creatinine levels (P = 0.02), international normalized ratios (P = 0.04), Child-Pugh scores (P = 0.002), and Model for End-Stage Liver Disease scores (P = 0.002). The median survival period after liver transplantation was 117 ± 17 months for sarcopenic patients and 146 ± 20 months for nonsarcopenic patients (P = 0.4). Sarcopenic patients had longer hospital stays (40 ± 4 versus 25 ± 3 days; P = 0.005) and a higher frequency of bacterial infections within the first 90 days after liver transplantation (26% versus 15%, P = 0.04) in comparison with nonsarcopenic patients. In conclusion, sarcopenia is one of the most common complications in patients with cirrhosis and is predictive of longer hospital stays and a higher risk of perioperative bacterial infections after liver transplantation, but it is not associated with increased mortality. Liver Transpl 20:640–648, 2014. © 2014 AASLD.
Stress–Strain Relations for Nematic Polymer Networks with Various Concentrations of Flexible and Stiff Parts
Authors: Walasek Janusz , Jedynak Radosław
Published: March 2014

A polymer network consists of linear chains. Each chain is an alternant sequence of flexible and stiff parts. The stiff parts of all the networked chains interact via nematic potential interactions. The flexible parts do not interact with other parts (flexible or stiff) of the network system. Various concentrations of flexible and stiff parts lend various elastic properties to the network. The influence of these molecular mechanisms on the stress–strain relations of the polymer network near the isotropic–nematic transition is calculated and discussed.
Mechanosensitivity may be enhanced in skeletal muscles of spinal cord–injured versus able‐bodied men
Authors: Yarar‐Fisher Ceren , Bickel C. Scott , Kelly Neil A. , Windham Samuel T. , Mclain Amie B. , Bamman Marcas M.
Published: March 2014

We investigated the effects of an acute bout of neuromuscular electrical stimulation–induced resistance exercise (NMES‐RE) on intracellular signaling pathways involved in translation initiation and mechanical loading–induced muscle hypertrophy in spinal cord–injured (SCI) versus able‐bodied (AB) individuals. AB and SCI individuals completed 90 isometric knee extension contractions at 30% of maximum voluntary or evoked contraction, respectively. Muscle biopsies were collected before, and 10 and 60 min after NMES‐RE. Protein levels of α7‐ and β1‐integrin, phosphorylated and total GSK‐3α/β, S6K1, RPS6, 4EBP1, and FAK were assessed by immunoblotting. SCI muscle appears to be highly sensitive to muscle contraction even several years after the injury, and in fact it may be more sensitive to mechanical stress than AB muscle. Heightened signaling associated with muscle mechanosensitivity and translation initiation in SCI muscle may be an attempted compensatory response to offset elevated protein degradation in atrophied SCI muscle. Muscle Nerve 50: 599–601, 2014
Respiratory assessment in centronuclear myopathies
Authors: Smith Barbara K. , Goddard Melissa , Childers Martin K.
Published: March 2014

The centronuclear myopathies (CNMs) are a group of inherited neuromuscular disorders classified as congenital myopathies. While several causative genes have been identified, some patients do not harbor any of the currently known mutations. These diverse disorders have common histological features, which include a high proportion of centrally nucleated muscle fibers, and clinical attributes of muscle weakness and respiratory insufficiency. Respiratory problems in CNMs may manifest initially during sleep, but daytime symptoms, ineffective airway clearance, and hypoventilation predominate as more severe respiratory muscle dysfunction evolves. Respiratory muscle capacity can be evaluated using a variety of clinical tests selected with consideration for the age and baseline motor function of the patient. Similar clinical tests of respiratory function can also be incorporated into preclinical CNM canine models to offer insight for clinical trials. Because respiratory problems account for significant morbidity in patients, routine assessments of respiratory muscle function are discussed. Muscle Nerve 50: 315–326, 2014
Rock me Avogadro
Authors: Osterath Brigitte
Published: March 2014

Fetzige Musikvideos machen Lust auf Wissenschaft: Sie peppen den Schulunterricht auf, zeigen die Forscherwelt oder animieren zu einer Ausbildung in der Chemieindustrie. Das Genre hat Potenzial, birgt aber auch Gefahren.
Informationen in neuem Gewand
Authors: Parlow Axel , Heineke Stephan
Published: March 2014

Die Produkte des FIZ Chemie sind nach einem fast zweijährigen Evaluierungs‐ und Akquisitionsprozess und einem Jahr der Eingewöhnung nun bei Wiley‐VCH integriert. Über seine neue Tochter Wiley Information Services in Berlin entwickelt der Verlag die Datenbanken, das Lernportal und die Internetpräsenz.
Hohe Nachfrage nach Unternehmen
Authors: Schneider Bernd
Published: March 2014

Die Chemie scheint den Abwärtstrend bei Transaktionen gebrochen zu haben. Die Unternehmen stehen an den Börsen gut da, und im Markt ist ausreichend Anlagekapital. Das ist gut für alle, die verkaufen wollen, stärkt aber auch die Kaufkraft von Interessenten. Deals mit deutschen Unternehmen wird es überwiegend auf internationaler Ebene geben.
Computational fluid dynamics simulation and theoretical study the air jet flow field of a wide slot positive pressure drawing assembly in the spunbonding nonwoven process
Authors: Zhao Bo
Published: March 2014

The polymer air‐drawing model of polyethylene terephthalate spunbonding nonwovens and the air jet flow field model in wide slot positive pressure spunbonding process have been established. The influence of the density and the specific heat capacity of polymer melt at constant pressure changing with polymer temperature on the fiber diameter have been studied, which is solved by introducing the numerical computation results of the air jet flow field of attenuator. It is simulated by means of the finite difference method. The predicted fiber diameter agrees with the experimental data. The effects of the processing parameters on the fiber diameter with the help of the image analysis method have been investigated. A higher inlet pressure, smaller slot width, and smaller jet angle will all cause higher z‐axis position of air velocity and air pressure, which are beneficial to the air drawing of the polymer melt and thus to reducing the fiber diameter. The experimental results show that the agreement between the results and experimental data is better, which verifies the reliability of these models. The results present great prospects for this research in the field of computer assisted design of spunbonding process, technology, and equipment. POLYM. ENG. SCI., 55:231–242, 2015. © 2014 Society of Plastics Engineers
Synthesis and characterization of first‐ and second‐generation polyamide pyridylimine nickel dihalide metallodendrimers and their uses as catalysts for ethylene polymerization
Authors: Ahamad Tansir , Alshehri Saad M
Published: March 2014

First‐ and second‐generation pyridylimine‐terminated dendrimeric ligands were prepared by the reaction of the corresponding amine‐terminated aromatic polyamide dendrimers with 2‐acetylpyridine. The pyridylimine terminal groups were used as bidentate N,N ligands of nickel halide to prepare the corresponding first‐generation and second‐generation nickel dihalide metallodendrimers C1 and C2, respectively. The synthesized dendrimers and metallodendrimers were characterized by elemental and spectral analyses. C1 and C2 were evaluated as catalyst precursors for ethylene oligomerization after being activated with methylaluminoxane (MAO) and diethylaluminum chloride (Et2AlCl) under 1 atm and 5 atm pressure of ethylene. In both cases, the use of 1 atm or 5 atm pressure of ethylene and a 1500:1 Al:Ni molar ratio for C1 and C2 resulted in high catalytic activities toward ethylene polymerization. Upon activation with MAO and Et2AlCl, C1 exhibited promising activities toward ethylene polymerization and produced linear chain structures that were associated with high density polyethylene. In contrast, C2 produced a polymer with the branching nature of low density polyethylene under similar conditions. © 2014 Society of Chemical Industry
An atypical presentation of pulmonary air‐leak syndrome and multisystem toxic epidermal necrolysis
Authors: Ellenburg Joseph T. , Josey David
Published: March 2014

Toxic epidermal necrolysis (TEN) is a rare and potentially fatal mucocutaneous condition that may affect both children and adults. TEN mortality rates vary greatly between both patient populations, but multisystem involvement is common. Management presents many challenges as there is no specific therapy for TEN, and patients often require the expertise of burn units. We report a child who survived TEN with multisystem involvement including the rare but life threatening occurrence of a pulmonary air‐leak syndrome while also reviewing controversies surrounding TEN's pathophysiology, sequelae, and multidisciplinary approach to management. Pediatr Pulmonol. 2014; 49:E130–E134. © 2014 Wiley Periodicals, Inc.
Lung function by impulse oscillometry at age 5–7 years after bronchiolitis at age 0–6 months
Authors: Lauhkonen Eero , Koponen Petri , Nuolivirta Kirsi , Paassilta Marita , Toikka Jyri , Korppi Matti
Published: March 2014

Background

Viral bronchiolitis in infancy has been associated with increased bronchial reactivity and reduced lung function in later childhood and even in adulthood. However, lung function at preschool age is less studied, mainly due to technical difficulties. The purpose of the study was to evaluate lung function and bronchial reactivity at preschool age in children who were hospitalized for bronchiolitis in early infancy.

Subjects and methods

Airway resistance and reactance, and bronchial reactivity to exercise were studied with impulse oscillometry (IOS) at the mean age of 6.3 years in 103 children hospitalized for bronchiolitis at less than 6 months of age.

Results

In baseline lung‐function measurement, resistance (n = 8; 7.8%) or reactance (19; 18.4%) at 5 Hz were pathological in 20% of children compared to Finnish population‐based height‐adjusted reference values. Increased bronchial reactivity by exercise challenge (5; 4.9%) or bronchodilatation (11; 10.7%) tests was present in 16%. Irreversible changes were revealed in only one case.

Conclusions

Though reduced lung function and increased airway reactivity were rather common, evidence for persistent lung function reduction was rare, less than 1%, at preschool age in children hospitalized for bronchiolitis caused mainly by respiratory syncytial virus at age less than 6 months. Pediatr Pulmonol. 2015; 50:389–395. © 2014 Wiley Periodicals, Inc.
Second antibody modeling assessment (AMA‐II)
Authors: Almagro Juan C. , Teplyakov Alexey , Luo Jinquan , Sweet Raymond W. , Kodangattil Sreekumar , Hernandez‐Guzman Francisco , Gilliland Gary L.
Published: March 2014

To assess the state of the art in antibody 3D modeling, 11 unpublished high‐resolution x‐ray Fab crystal structures from diverse species and covering a wide range of antigen‐binding site conformations were used as a benchmark to compare Fv models generated by seven structure prediction methodologies. The participants included: Accerlys Inc, Chemical Computer Group (CCG), Schrodinger, Jeff Gray's lab at John Hopkins University, Macromoltek, Astellas Pharma/Osaka University and Prediction of ImmunoGlobulin Structure (PIGS). The sequences of benchmark structures were submitted to the modelers and PIGS, and a set of models were generated for each structure. We provide here an overview of the organization, participants and main results of this second antibody modeling assessment (AMA‐II). Also, we compare the results with the first antibody assessment published in this journal (Almagro et al., 2011;79:3050). Proteins 2014; 82:1553–1562. © 2014 Wiley Periodicals, Inc.
A Trust Evaluation Model for E‐Learning Systems
Authors: Tan Wenan , Chen Senbo , Li Jingxian , Li Lingxia , Wang Tong , Hu Xiaoming
Published: March 2014

In recent years, electronic learning (e‐learning) has become an increasingly important method in education. Under the environment of Internet of Things, it has been predicted that e‐learning systems will grow at an even greater pace. Therefore, it is crucial to find a simple and effective evaluation method to assess user trust in e‐learning systems. In this paper, we present an evaluation model based on user trust cloud and user capability for trusted e‐learning. A user trust cloud model is proposed to assess a user's subjective trust, and a capability matrix method is introduced to assess a user's objective trust. The proposed model has been implemented for trust management in e‐learning systems. Experimental results show that the proposed trust evaluation model is useful and applicable to the user trust assessment in complex e‐learning systems. Copyright © 2014 John Wiley & Sons, Ltd.
Critical Role of Jak2 in the Maintenance and Function of Adult Hematopoietic Stem Cells
Authors: Akada Hajime , Akada Saeko , Hutchison Robert E. , Sakamoto Kazuhito , Wagner Kay-Uwe , Mohi Golam
Published: March 2014

Jak2, a member of the Janus kinase family of nonreceptor protein tyrosine kinases, is activated in response to a variety of cytokines, and functions in survival and proliferation of cells. An activating JAK2V617F mutation has been found in most patients with myeloproliferative neoplasms, and patients treated with Jak2 inhibitors show significant hematopoietic toxicities. However, the role of Jak2 in adult hematopoietic stem cells (HSCs) has not been clearly elucidated. Using a conditional Jak2 knockout allele, we have found that Jak2 deletion results in rapid loss of HSCs/progenitors leading to bone marrow failure and early lethality in adult mice. Jak2 deficiency causes marked impairment in HSC function, and the mutant HSCs are severely defective in reconstituting hematopoiesis in recipient animals. Jak2 deficiency also causes significant apoptosis and loss of quiescence in HSC-enriched LSK (Lin−Sca-1+c-Kit+) cells. Jak2-deficient LSK cells exhibit elevated reactive oxygen species levels and enhanced p38 MAPK activation. Mutant LSK cells also show defective Stat5, Erk, and Akt activation in response to thrombopoietin and stem cell factor. Gene expression analysis reveals significant downregulation of genes related to HSC quiescence and self-renewal in Jak2-deficient LSK cells. These data suggest that Jak2 plays a critical role in the maintenance and function of adult HSCs. Stem Cells  2014;32:1878–1889
Modification of glycolysis and its effect on the production ofl-threonine inEscherichia coli
Authors: Xie Xixian , Liang Yuan , Liu Hongliang , Liu Yuan , Xu Qingyang , Zhang Chenglin , Chen Ning
Published: March 2014

High concentrations of acetate, the main by-product of Escherichia coli (E. coli) high cell density culture, inhibit bacterial growth and l-threonine production. Since metabolic overflux causes acetate accumulation, we attempted to reduce acetate production by redirecting glycolysis flux to the pentose phosphate pathway by deleting the genes encoding phosphofructokinase (pfk) and/or pyruvate kinase (pyk) in an l-threonine-producing strain of E. coli, THRD. pykF, pykA, pfkA, and pfkB deletion mutants produced less acetate (9.44 ± 0.83, 3.86 ± 0.88, 0.30 ± 0.25, and 6.99 ± 0.85 g/l, respectively) than wild-type THRD cultures (19.75 ± 0.93 g/l). THRDΔpykF and THRDΔpykA produced 11.05 and 5.35 % more l-threonine, and achieved a 10.91 and 5.60 % higher yield on glucose, respectively. While THRDΔpfkA grew more slowly and produced less l-threonine than THRD, THRDΔpfkB produced levels of l-threonine (102.28 ± 2.80 g/l) and a yield on glucose (0.34 g/g) similar to that of THRD. The dual deletion mutant THRDΔpfkBΔpykF also achieved low acetate (7.42 ± 0.81 g/l) and high l-threonine yields (111.37 ± 2.71 g/l). The level of NADPH in THRDΔpfkA cultures was depressed, whereas all other mutants produced more NADPH than THRD did. These results demonstrated that modification of glycolysis in E. coli THRD reduced acetate production and increased accumulation of l-threonine.
“Reversed” intraguild predation: red fox cubs killed by pine marten
Authors: Brzeziński Marcin , Rodak Łukasz , Zalewski Andrzej
Published: March 2014

Camera traps deployed at a badger Meles meles set in mixed pine forest in north-eastern Poland recorded interspecific killing of red fox Vulpes vulpes cubs by pine marten Martes martes. The vixen and her cubs settled in the set at the beginning of May 2013, and it was abandoned by the badgers shortly afterwards. Five fox cubs were recorded playing in front of the den each night. Ten days after the first recording of the foxes, a pine marten was filmed at the set; it arrived in the morning, made a reconnaissance and returned at night when the vixen was away from the set. The pine marten entered the den several times and killed at least two fox cubs. It was active at the set for about 2 h. This observation proves that red foxes are not completely safe from predation by smaller carnivores, even those considered to be subordinate species in interspecific competition.
Antifreeze activity enhancement by site directed mutagenesis on an antifreeze protein from the beetle Rhagium mordax
Authors: Friis Dennis Steven , Kristiansen Erlend , von Solms Nicolas , Ramløv Hans
Published: March 2014

The ice binding motifs of insect antifreeze proteins (AFPs) mainly consist of repetitive TxT motifs aligned on a flat face of the protein. However, these motifs often contain non‐threonines that disrupt the TxT pattern. We substituted two such disruptive amino acids located in the ice binding face of an AFP from Rhagium mordax with threonine. Furthermore, a mutant with an extra ice facing TxT motif was constructed. These mutants showed enhanced antifreeze activity compared to the wild type at low concentrations. However, extrapolating the data indicates that the wild type will become the most active at concentrations above 270 μmol.