bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved Thermoelectric Performance of Silver Nanoparticles‐Dispersed Bi2Te3 Composites Deriving from Hierarchical Two‐Phased Heterostructure
Authors: Zhang Qihao , Ai Xin , Wang Lianjun , Chang Yanxia , Luo Wei , Jiang Wan , Chen Lidong
Published: December 2014

A practical and feasible bottom‐up chemistry approach is demonstrated to dramatically enhance thermoelectric properties of the Bi2Te3 matrix by means of exotically introducing silver nanoparticles (AgNPs) for constructing thermoelectric composites with the hierarchical two‐phased heterostructure. By regulating the content of AgNPs and fine‐tuning the architecture of nanostructured thermoelectric materials, more heat‐carrying phonons covering the broad phonon mean free path distribution range can be scattered. The results show that the uniformly dispersed AgNPs not only effectively suppress the growth of Bi2Te3 grains, but also introduce nanoscale precipitates and form new interfaces with the Bi2Te3 matrix, resulting in a hierarchical two‐phased heterostructure, which causes intense scattering of phonons with multiscale mean free paths, and therefore significantly reduce the lattice thermal conductivity. Meanwhile, the improved power factor is maintained due to low‐energy electron filtering and excellent electrical transport property of Ag itself. Consequently, the maximum ZT is amazingly found to be enhanced by 304% arising from the hierarchical heterostructure when the AgNPs content reaches 2.0 vol%. This study offers an easily scalable and low‐cost route to construct a wide range of multiscale hierarchically heterostructured bulk composites with significant enhancement of thermoelectric performance.
Electronic Structures and Photoconversion Mechanism in Perovskite/Fullerene Heterojunctions
Authors: Lo Ming‐Fai , Guan Zhi‐Qiang , Ng Tsz‐Wai , Chan Chiu‐Yee , Lee Chun‐Sing
Published: December 2014

It has been generally believed and assumed that organometal halide perovskites would form type II P–N junctions with fullerene derivatives (C60 or PCBM), and the P–N junctions would provide driving force for exciton dissociation in perovskite‐based solar cell. To the best of our knowledge, there is so far no experiment proof on this assumption. On the other hand, whether photogenerated excitons can intrinsically dissociate into free carrier in the perovskite without any assistance from a P–N junction is still controversial. To address these, the interfacial electronic structures of a vacuum‐deposited perovskite/C60 and a solution‐processed perovskite/PCBM junctions is directly measured by ultraviolet photoelectron spectroscopy. Contrary to the common believes, both junctions are found to be type I N–N junctions with band gap of the perovskites embedded by that of the fullerenes. Meanwhile, device with such a charge inert junction can still effectively functions as a solar cell. These results give direct experimental evidence that excitons are dissociated to free carriers in the perovskite film even without any assistance from a P–N junction.
Facile One‐Step Micropatterning Using Photodegradable Gelatin Hydrogels for Improved Cardiomyocyte Organization and Alignment
Authors: Tsang Kelly M. C. , Annabi Nasim , Ercole Francesca , Zhou Kun , Karst Daniel J. , Li Fanyi , Haynes John M. , Evans Richard A. , Thissen Helmut , Khademhosseini Ali , Forsythe John S.
Published: December 2014

Hydrogels are often employed as temporary platforms for cell proliferation and tissue organization in vitro. Researchers have incorporated photodegradable (PD) moieties into synthetic polymeric hydrogels as a means of achieving spatiotemporal control over material properties. In this study protein‐based PD hydrogels composed of methacrylated gelatin and a crosslinker containing o‐nitrobenzyl ester groups are developed. The hydrogels are able to degrade rapidly and specifically in response to UV light and can be photopatterned to a variety of shapes and dimensions in a one‐step process. Micropatterned PD hydrogels are shown to improve cell distribution, alignment, and beating regularity of cultured neonatal rat cardiomyocytes. Overall this work introduces a new class of PD hydrogel based on natural and biofunctional polymers as cell culture substrates for improving cellular organization and function.
On‐Demand Wrinkling Patterns in Thin Metal Films Generated from Self‐Assembling Liquid Crystals
Authors: de Haan Laurens T. , Leclère Philippe , Damman Pascal , Schenning Albertus P. H. J. , Debije Michael G.
Published: December 2014

In this work, a new, universal method is described that uses the photopatterning of liquid crystals, which is accurately translated into a controlled, intricately wrinkled metal surface. Remarkably, the patterns have an oscillation in amplitude of the wrinkles. This rapid method allows generation of intricate multidomain patterns and continuous circular structures, including azimuthal, radial, and even higher complexity arrangements as examples. These wrinkled gold surfaces are also strikingly visual, which is interesting for applications ranging from diffractive elements to fine jewelry.
Large‐Area Low‐Cost Tunable Plasmonic Perfect Absorber in the Near Infrared by Colloidal Etching Lithography
Authors: Walter Ramon , Tittl Andreas , Berrier Audrey , Sterl Florian , Weiss Thomas , Giessen Harald
Published: January 2015

Optical elements with absorbance close to unity are of crucial importance for diverse applications, ranging from thermal imaging to sensitive trace gas detection. A key factor for the performance of such devices is the need for absorbance with high acceptance angles, which are able to utilize all incident radiation from the forward‐facing half‐space. Here, a tunable, angle‐, and polarization independent large‐area perfect absorber is reported, which is fabricated by a combination of colloidal lithography and dry‐etching. This design is easy and fast to produce, and low‐cost compared with other common methods. Variation of the dry‐etching time shifts the resonance from almost 825 to 1025 nm with reflection smaller than 3% and zero transmission. Due to the inherent disordered arrangement, this design is fully polarization independent and the absorbance remains higher than 98% for incident angles up to 50°.
Combination therapy with a Tmprss6RNAi‐therapeutic and the oral iron chelator deferiprone additively diminishes secondary iron overload in a mouse model of β‐thalassemia intermedia
Authors: Schmidt Paul J. , Racie Tim , Westerman Mark , Fitzgerald Kevin , Butler James S. , Fleming Mark D.
Published: January 2015

β‐thalassemias result from diminished β‐globin synthesis and are associated with ineffective erythropoiesis and secondary iron overload caused by inappropriately low levels of the iron regulatory hormone hepcidin. The serine protease TMPRSS6 attenuates hepcidin production in response to iron stores. Hepcidin induction reduces iron overload and mitigates anemia in murine models of β‐thalassemia intermedia. To further interrogate the efficacy of an RNAi‐therapeutic downregulating Tmprss6, β‐thalassemic Hbbth3/+ animals on an iron replete, an iron deficient, or an iron replete diet also containing the iron chelator deferiprone were treated with Tmprss6 siRNA. We demonstrate that the total body iron burden is markedly improved in Hbbth3/+ animals treated with siRNA and chelated with oral deferiprone, representing a significant improvement compared to either compound alone. These data indicate that siRNA suppression of Tmprss6, in conjunction with oral iron chelation therapy, may prove superior for treatment of anemia and secondary iron loading seen in β‐thalassemia intermedia. Am. J. Hematol. 90:310–313, 2015. © 2015 The Authors. American Journal of Hematology Published by Wiley Periodicals, Inc.
Dealing with the complex drug–drug interactions: Towards mechanistic models
Authors: Varma Manthena V. , Pang K. Sandy , Isoherranen Nina , Zhao Ping
Published: December 2014

Unmanageable severe adverse events caused by drug‐drug interactions (DDIs), leading to market withdrawals or restrictions in the clinical usage, are increasingly avoided with the improvement in our ability to predict such DDIs quantitatively early in drug development. However, significant challenges arise in the evaluation and/or prediction of complex DDIs caused by inhibitor drugs and/or metabolites that affect not one but multiple pathways of drug clearance. This review summarizes the discussion topics at the 2013 AAPS symposium on “Dealing with the complex drug‐drug interactions: towards mechanistic models”. Physiologically based pharmacokinetic (PBPK) models, in combination with the established in vitro‐to‐in vivo extrapolations of intestinal and hepatic disposition, have been successfully applied to predict clinical pharmacokinetics and DDIs, especially for drugs with CYP‐mediated metabolism, and to explain transporter‐mediated and complex DDIs. Although continuous developments are being made towards improved mechanistic prediction of the transporter‐enzyme interplay in the hepatic and intestinal disposition and characterizing the metabolites contribution to DDIs, the prediction of DDIs involving them remains difficult. Regulatory guidelines also recommended use of PBPK modeling for the quantitative prediction and evaluation of DDIs involving multiple perpetrators and metabolites. Such mechanistic modeling approaches culminate to the consensus that modeling is helpful in predicting DDIs or quantitatively rationalizing the clinical findings in complex situations. Furthermore, they provide basis for the prediction and/or understanding the pharmacokinetics in populations like patients with renal impairment, pediatrics, or various ethnic groups where the conduct of clinical studies might not be feasible in early drug development stages and yet some guidance on management of dosage is necessary. Copyright © 2014 John Wiley & Sons, Ltd.
Modeling of the pharmacokinetic/pharmacodynamic interaction between irbesartan and hydrochlorothiazide in normotensive subjects
Authors: Hedaya Mohsen A. , Helmy Sally A.
Published: December 2014

Purpose

To investigate the pharmacokinetic/pharmacodynamic (PK/PD) interaction between irbesartan (IRB) and hydrochlorothiazide (HCT) in normotensive subjects.

Methods

A three‐way crossover study was used. Serial drug concentrations and drug effects, including systolic and diastolic blood pressure and heart rate were monitored after administration of irbesartan and hydrochlorothiazide alone and in combination. The data were fitted to a PK/PD model and the parameters for irbesartan and hydrochlorothiazide when administered alone and in combination were compared.

Results

The plasma profiles for irbesartan and hydrochlorothiazide followed the two‐compartment model after a single dose. The PK parameters of irbesartan were not affected by hydrochlorothiazide; however irbesartan decreased the hydrochlorothiazide AUC by 25% and increased its clearance by 25%. There were no significant changes in heart rate after each drug alone or in combination. Irbesartan plus hydrochlorothiazide had a greater blood pressure lowering effect compared with irbesartan alone, despite the unchanged irbesartan PK. The relationship between irbesartan plasma concentration and its effects plotted in chronological order showed anticlockwise hysteresis. The PD parameter estimates for the effect of irbesartan on systolic blood pressure, when administered with hydrochlorothiazide were significantly different from those when irbesartan was administered alone. This was manifested by a 25% increase in Emax, and a 40% decrease in EC50, suggesting a synergistic blood pressure lowering effect for the combination. While parameter estimates for the effect of irbesartan on diastolic blood pressure were changed by hydrochlorothiazide, the differences were only significant for EC50.

Conclusion

A limited potential for clinically significant interactions between irbesartan and hydrochlorothiazide at the given doses were observed; therefore, no dosage adjustments were recommended for either drug when used together. (ClinicalTrials.gov Identifier NCT01858610) Copyright © 2014 John Wiley & Sons, Ltd.
Golgi defects enhance APP amyloidogenic processing in Alzheimer's disease
Authors: Joshi Gunjan , Wang Yanzhuang
Published: December 2014

Increased amyloid beta (Aβ) production by sequential cleavage of the amyloid precursor protein (APP) by the β‐ and γ‐secretases contributes to the etiological basis of Alzheimer's disease (AD). This process requires APP and the secretases to be in the same subcellular compartments, such as the endosomes. Since all membrane organelles in the endomembrane system are kinetically and functionally linked, any defects in the trafficking and sorting machinery would be expected to change the functional properties of the whole system. The Golgi is a primary organelle for protein trafficking, sorting and modifications, and Golgi defects have been reported in AD. Here we hypothesize that Golgi fragmentation in AD accelerates APP trafficking and Aβ production. Furthermore, Golgi defects may perturb the proper trafficking and processing of many essential neuronal proteins, resulting in compromised neuronal function. Therefore, molecular tools that can restore Golgi structure and function could prove useful as potential drugs for AD treatment.
One‐way trip: Influenza virus' adaptation to gallinaceous poultry may limit its pandemic potential
Authors: Long Jason S. , Benfield Camilla T. , Barclay Wendy S.
Published: December 2014

We hypothesise that some influenza virus adaptations to poultry may explain why the barrier for human‐to‐human transmission is not easily overcome once the virus has crossed from wild birds to chickens. Since the cluster of human infections with H5N1 influenza in Hong Kong in 1997, chickens have been recognized as the major source of avian influenza virus infection in humans. Although often severe, these infections have been limited in their subsequent human‐to‐human transmission, and the feared H5N1 pandemic has not yet occurred. Here we examine virus adaptations selected for during replication in chickens and other gallinaceous poultry. These include altered receptor binding and increased pH of fusion of the haemagglutinin as well as stalk deletions of the neuraminidase protein. This knowledge could aid the delivery of vaccines and increase our ability to prioritize research efforts on those viruses from the diverse array of avian influenza viruses that have greatest human pandemic potential.

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MAPping the Ndc80 loop in cancer: A possible link between Ndc80/Hec1 overproduction and cancer formation
Authors: Tang Ngang Heok , Toda Takashi
Published: January 2015

Mis‐regulation (e.g. overproduction) of the human Ndc80/Hec1 outer kinetochore protein has been associated with aneuploidy and tumourigenesis, but the genetic basis and underlying mechanisms of this phenomenon remain poorly understood. Recent studies have identified the ubiquitous Ndc80 internal loop as a protein‐protein interaction platform. Binding partners include the Ska complex, the replication licensing factor Cdt1, the Dam1 complex, TACC‐TOG microtubule‐associated proteins (MAPs) and kinesin motors. We review the field and propose that the overproduction of Ndc80 may unfavourably absorb these interactors through the internal loop domain and lead to a change in the equilibrium of MAPs and motors in the cells. This sequestration will disrupt microtubule dynamics and the proper segregation of chromosomes in mitosis, leading to aneuploid formation. Further investigation of Ndc80 internal loop‐MAPs interactions will bring new insights into their roles in kinetochore‐microtubule attachment and tumourigenesis.
Study on the interaction of plasma protein binding rate between edaravone and taurine in human plasma based on HPLC analysis coupled with ultrafiltration technique
Authors: Tang Dao‐quan , Li Yin‐jie , Li Zheng , Bian Ting‐ting , Chen Kai , Zheng Xiao‐xiao , Yu Yan‐yan , Jiang Shui‐shi
Published: December 2014

In this work, two high‐performance liquid chromatography (HPLC) assays were developed and validated for the independent determination of edaravone and taurine using 3‐methyl‐1‐p‐tolyl‐5‐pyrazolone and L‐glutamine as internal standards. In in vitro experiments, human plasma was separately spiked with a mixture of edaravone and taurine, edaravone or taurine alone. Plasma was precipitated with acetonitrile containing 0.1% formic acid. Ultrafiltration was employed to obtain the unbound ingredients of the two drugs. The factors that might influence the ultrafiltration effiency were elaborately optimized. Plasma supernatant and ultrafiltrate containing taurine were derivated with o‐phthalaldehyde and ethanethiol in the presence of 40 mmol/L sodium borate buffer (pH 10.2) at room temperature within 1 min. Chromatographic separations were achieved on an InertSustain C18 column (250 × 4.6 mm, 5 µm). Isocratic 50 mmol/L ammonium acetate–acetonitrile and gradient 50 mmol/L sodium acetate (pH 5.3)–methanol were respectively selected as the mobile phase for the determination of edaravone and taurine. All of the validation data including linearity, extraction recovery, precision, accuracy and stability conformed to the requirements. Results showed that there were no significant alterations in the plasma protein binding rate of taurine and edaravone, implying that the proposed combination therapy was pharmacologically feasible. Copyright © 2014 John Wiley & Sons, Ltd.
3D printed models for planning endovascular stenting in transverse aortic arch hypoplasia
Authors: Valverde Israel , Gomez Gorka , Coserria Jose Felix , Suarez‐Mejias Cristina , Uribe Sergio , Sotelo Julio , Velasco Maria Nieves , Santos De Soto Jose , Hosseinpour Amir‐Reza , Gomez‐Cia Tomas
Published: January 2015

Objectives

To evaluate whether three‐dimensional (3D) printed models can be used to improve interventional simulation and planning in patients with aortic arch hypoplasia. Background: Stenting of a hypoplastic transverse arch is technically challenging, and complications such as stent migration and partial obstruction of the origin of the head and neck vessels are highly dependent on operator skills and expertise. Methods: Using magnetic resonance imaging (MRI) data, a 3D model of a repaired aortic coarctation of a 15‐year‐old boy with hypoplastic aortic arch was printed. Simulation of the endovascular stenting of the hypoplastic arch was carried out under fluoroscopic guidance in the 3D printed model, and subsequently in the patient. A Bland–Altman analysis was used to evaluate the agreement between measurements of aortic diameter in the 3D printed model and the patient's MRI and X‐ray angiography. Results: The 3D printed model proved to be radio‐opaque and allowed simulation of the stenting intervention. The assessment of optimal stent position, size, and length was found to be useful for the actual intervention in the patient. There was excellent agreement between the 3D printed model and both MRI and X‐ray angiographic images (mean bias and standard deviation of 0.36 ± 0.45 mm). Conclusions: 3D printed models accurately replicate patients' anatomy and are helpful in planning endovascular stenting in transverse arch hypoplasia. This opens a door for potential simulation applications of 3D models in the field of catheterization and cardiovascular interventions. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.
Porous Medium Model in Computational Fluid Dynamics Simulation of a Honeycombed SCR DeNOx Catalyst
Authors: Yao Jie , Zhong Zhaoping , Zhu Lin
Published: January 2015

The commercial computational fluid dynamics software FLUENT was used to simulate the flow and chemical reaction process of a honeycombed SCR DeNOx catalyst. In the calculation model, the porous medium model was applied to describe the wall body region of the honeycombed catalyst and the ordinary flow model in order to define the honeycombed channel region. From the comparison between the two gas diffusion rates within catalyst pore structure and gas medium, their effects on the SCR DeNOx reaction rate were analyzed. A correction factor of the chemical reaction rate was created to modify the porous medium model in order to accurately calculate the chemical reaction process of the catalyst model. The study results indicated that the combination between porous medium model and reaction rate correction factor could compensate the deviation of calculated reaction rate and the interfacial diffusion problems.
Synthesis, Characterization, and Catalytic Activity of Mn‐doped Perovskite Oxides for Three‐Way Catalysis
Authors: Zhou Chen , Zhang Yexin , Hu Lingjun , Yin Hongfeng , Guo Wang Wei
Published: January 2015

Mn‐doped La0.8Sr0.2CoO3 perovskite oxides (La0.8Sr0.2Co1–xMnxO3; x = 0, 0.1, 0.3, 0.5) were synthesized by a modified sol‐gel method. The phase‐pure oxides were obtained. CoO and carbonates were formed on the surface of La0.8Sr0.2CoO3. With increasing doping content, these impurities were reduced while the stability of the perovskite structure was improved. The valence state of B‐site ions and the amount of absorbed oxygen were influenced by Mn doping. The catalytic activity of the perovskite catalysts was investigated for CO oxidation and simultaneous removal of CO, C3H8, and NO. For CO and NO removal, La0.8Sr0.2Co0.9Mn0.1O3 exhibited the best performance. For C3H8 removal, the reactivity was promoted linearly with the doping content. The structure‐activity relationship is also discussed.
Velocity Distribution inside a Laminated‐Sheet Microchannel Reactor
Authors: Pan Minqiang , Li Lei , Shao Xiaojia , Zeng Dehuai
Published: January 2015

In a laminated‐sheet microchannel reactor, several microchannel sheets with the same or different structures are mutually laminated together. The effect of microchannel and manifold structure as well as the number of laminated sheets on the velocity distribution among microchannels in each sheet with the same structure is investigated. Results indicate that a large microchannel length, a high‐aspect‐ratio microchannel, and centrosymmetric manifold structure are favorable for a relatively uniform velocity distribution in each sheet. Considering the centrosymmetric manifold structure, a shorter distance from inlet and outlet to microchannels in direction of the microchannel width and a longer distance to the microchannel array in direction of the microchannel length can contribute to a more uniform velocity distribution. The laminated‐sheet number has only a minor impact on the velocity distribution among microchannels in each sheet.
Pharmacokinetic drug–drug interaction assessment of LCZ696 (an angiotensin receptor neprilysin inhibitor) with omeprazole, metformin or levonorgestrel‐ethinyl estradiol in healthy subjects
Authors: Gan Lu , Jiang Xuemin , Mendonza Anisha , Swan Therese , Reynolds Christine , Nguyen Joanne , Pal Parasar , Neelakantham Srikanth , Dahlke Marion , Langenickel Thomas , Rajman Iris , Akahori Mizuki , Zhou Wei , Rebello Sam , Sunkara Gangadhar
Published: January 2015

LCZ696 is a novel angiotensin receptor neprilysin inhibitor in development for the treatment of cardiovascular diseases. Here, we assessed the potential for pharmacokinetic drug‐drug interaction of LCZ696 (400 mg, single dose or once daily [q.d.]) when co‐administered with omeprazole 40 mg q.d. (n = 28) or metformin 1000 mg q.d. (n = 27) or levonorgestrel‐ethinyl estradiol 150/30 μg single dose (n = 24) in three separate open‐label, single‐sequence studies in healthy subjects. Pharmacokinetic parameters of LCZ696 analytes (sacubitril, LBQ657, and valsartan), metformin, and levonorgestrel‐ethinyl estradiol were assessed. Omeprazole did not alter the AUCinf of sacubitril and pharmacokinetics of LBQ657; however, 7% decrease in the Cmax of sacubitril, and 11% and 13% decreases in AUCinf and Cmax of valsartan were observed. Co‐administration of LCZ696 with metformin had no significant effect on the pharmacokinetics of LBQ657 and valsartan; however, AUCtau,ss and Cmax,ss of metformin were decreased by 23%. Co‐administration of LCZ696 with levonorgestrel‐ethinyl estradiol had no effect on the pharmacokinetics of ethinyl estradiol and LBQ657 or AUCinf of levonorgestrel. The Cmax of levonorgestrel decreased by 15%, and AUCtau,ss and Cmax,ss of valsartan decreased by 14% and 16%, respectively. Co‐administration of LCZ696 with omeprazole, metformin, or levonorgestrel‐ethinyl estradiol was not associated with any clinically relevant pharmacokinetic drug interactions.
Growth of a Carbon Micro‐ and Nanocoils Mixture using NiSO4 as the Catalyst Precursor
Authors: Cui Ruixue , Li Dawei , Fu Xin , Asif Muhammad , Pan Lujun
Published: January 2015

A mixture of carbon micro‐ and nanocoils (CMCs/CNCs) is synthesized by catalytic pyrolysis of acetylene at 650 °C using NiSO4 as the catalyst precursor. The morphology of the grown product is analyzed by scanning electron microscopy (SEM). Experimental results indicate that, in general, the CMCs are in double‐helical form, while most of the grown CNCs are in twisted single‐helical form. The coil diameters of CMCs and CNCs are approximately 4 to 10 mm and 300 to 400 nm, respectively. Raman spectra indicate that the real active catalyst precursor for growing CMCs/CNCs is NiSO4, while NiO is not an effective catalyst precursor for synthesizing CMCs or CNCs.
Expanding the scope of pressure‐assisted electrokinetic injection for online concentration of positively charged analytes in capillary electrophoresis‐mass spectrometry
Authors: D'Ulivo Lucia , Feng Yong‐Lai
Published: December 2014

Sample injection is a crucial step in CE. In past, many efforts have been focused on concentrating the analytes into a sharp sample plug. In 2006, pressure‐assisted electrokinetic injection (PAEKI) was proposed as a new preconcentration technique for anions. In this study, we expanded the applicability of PAEKI to online preconcentrate positively charged analytes. l‐Arginine, l‐lysine, and imidazole were chosen as target analytes for method development. The enhancement factor of PAEKI was over 3000‐fold. When CZE was coupled with a Q‐TOF system, PAEKI delivers a detection limit of 18–28 pg/mL and a dynamic calibration range over four orders of magnitude. The RSD was less than 6.4% (n = 4) on both peak area and migration time, indicating a good repeatability.
Retinal proteins associated with redox regulation and protein folding play central roles in response to high glucose conditions
Authors: Wang Ssu‐Han , Lee Wen‐Chi , Chou Hsiu‐Chuan
Published: December 2014

Diabetic retinopathy typically causes poor vision and blindness. A previous study revealed that a high blood glucose concentration induces glycoxidation and weakens the retinal capillaries. Nevertheless, the molecular mechanisms underlying the effects of high blood glucose induced diabetic retinopathy remain to be elucidated. In the present study, we cultured the retinal pigmented epithelial cell line ARPE‐19 in mannitol‐balanced 5.5, 25, and 100 mM glucose media and investigated protein level alterations. Proteomic analysis revealed significant changes in 137 protein features, of which 124 demonstrated changes in a glucose concentration dependent manner. Several proteins functionally associated with redox regulation, protein folding, or the cytoskeleton are affected by increased glucose concentrations. Additional analyses also revealed that cellular oxidative stress, including endoplasmic reticulum stress, was significantly increased after treatment with high glucose concentrations. However, the mitochondrial membrane potential and cell survival remained unchanged during treatment with high glucose concentrations. To summarize, in this study, we used a comprehensive retinal pigmented epithelial cell based proteomic approach for identifying changes in protein expression associated retinal markers induced by high glucose concentrations. Our results revealed that a high glucose condition can induce cellular oxidative stress and modulate the levels of proteins with functions in redox regulation, protein folding, and cytoskeleton regulation; however, cell viability and mitochondrial integrity are not significantly disturbed under these high glucose conditions.
Determinants of sediment properties and organic matter in beach and dune environments based on boosted regression trees
Authors: Nylén Tua , Hellemaa Pirjo , Luoto Miska
Published: December 2014

Grain size properties and the variation of organic matter in coastal beach and dune environments are assumed to be controlled by the intensity of aeolian processes, time and the sediment source. However, assumptions are based on relatively limited empirical studies. In this study, we examined which environmental variables are the main predictors of multiple topsoil properties. To achieve this, we analysed an extensive dataset systematically collected across all beach zones and a large geographical area at the Finnish Baltic Sea coast characterized by post‐glacial land uplift. We included a comprehensive set of predictors in the analysis and applied boosted regression trees, a modern modelling technique particularly suited for analysis without prior assumptions of the data model. The results suggest that mean grain size and sorting are mainly determined by northing and fetch. Northing, disturbance and fetch predicted the variation of soil organic matter while litter cover was strongly related to disturbance. Based on the analyses, we were able to identify the main drivers of multiple topsoil properties on land uplift beaches. Parent material is suggested to determine sediment textural properties, which largely masks the effects of transient processes. Mean grain size and sorting are highly interdependent: grains become finer and sorting improves with increasing shore exposure. The intensity of momentary geomorphic processes controls the accumulation of litter whereas the slower accumulation of organic matter in the soil is influenced also by the static exposure setting. Skewness and kurtosis of the grain size distribution are mainly influenced by unmeasured processes, potentially relating to the geomorphological origin of the sediment. Copyright © 2014 John Wiley & Sons, Ltd.
Co‐evolution of riparian vegetation and channel dynamics in an aggrading braided river system, Mount Pinatubo, Philippines
Authors: Gran Karen B. , Tal Michal , Wartman Emily D.
Published: December 2014

Increased bank stability by riparian vegetation can have profound impacts on channel morphology and dynamics in low‐energy systems, but the effects are less clear in high‐energy environments. Here we investigate the role of vegetation in active, aggrading braided systems at Mount Pinatubo, Philippines, and compare results with numerical modeling results. Gradual reductions in post‐eruption sediment loads have reduced bed reworking rates, allowing vegetation to finally persist year‐round on the Pasig‐Potrero and Sacobia Rivers. From 2009–2011 we collected data detailing vegetation extent, type, density, and root strength. Incorporating these data into the RipRoot model and BSTEM (Bank Stability and Toe Erosion Model) shows cohesion due to roots increases from zero in unvegetated conditions to > 10·2 kPa in densely‐growing grasses. Field‐based parameters were incorporated into a cellular model comparing vegetation strength and sediment mobility effects on braided channel dynamics. The model shows both low sediment mobility and high vegetation strength lead to less active systems, reflecting trends observed in the field. The competing influence of vegetation strength versus channel dynamics is a concept encapsulated in a dimensionless ratio between timescales for vegetation growth and channel reworking known as T*. An estimated T* between 1·5 and 2·3 for the Pasig‐Potrero River suggests channels are still very mobile and likely to remain braided until aggradation rates decline further. Vegetation does have an important effect on channel dynamics, however, by focusing flow and thus aggradation into the unvegetated fraction of braidplain, leading to an aggradational imbalance and transition to a more avulsive state. The future trajectory of channel–vegetation interactions as sedimentation rates decline is complicated by strong seasonal variability in precipitation and sediment loads, driving incision and armoring in the dry season. By 2011, incision during the dry season was substantial enough to lower the water‐table, weaken existing vegetation, and allow for vegetation removal in future avulsions. Copyright © 2015 John Wiley & Sons, Ltd.
Assessment of radium-226 bioavailability and bioaccumulation downstream of decommissioned uranium operations, using the caged oligochaete (Lumbriculus variegatus)
Authors: Wiramanaden Cheryl I.E. , Orr Patricia L. , Russel Cynthia K.
Published: January 2015

The present study investigated the integrated effects of several geochemical processes that control radium-226 (226Ra) mobility in the aquatic environment and bioaccumulation in in situ caged benthic invertebrates. Radium-226 bioaccumulation from sediment and water was evaluated using caged oligochaetes (Lumbriculus variegatus) deployed for 10 d in 6 areas downstream of decommissioned uranium operations in Ontario and Saskatchewan, Canada. Measured 226Ra radioactivity levels in the retrieved oligochaetes did not relate directly to water and sediment exposure levels. Other environmental factors that may influence 226Ra bioavailability in sediment and water were investigated. The strongest mitigating influence on 226Ra bioaccumulation factors was sediment barium concentration, with elevated barium (Ba) levels being related to use of barium chloride in effluent treatment for removing 226Ra through barite formation. Observations from the present study also indicated that 226Ra bioavailability was influenced by dissolved organic carbon in water, and by gypsum, carbonate minerals, and iron oxyhydroxides in sediment, suggestive of sorption processes. Environmental factors that appeared to increase 226Ra bioaccumulation were the presence of other group (II) ions in water (likely competing for binding sites on organic carbon molecules), and the presence of K-feldspars in sediment, which likely act as a dynamic repository for 226Ra where weak ion exchange can occur. In addition to influencing bioavailability to sediment biota, secondary minerals such as gypsum, carbonate minerals, and iron oxyhydroxides likely help mitigate 226Ra release into overlying water after the dissolution of sedimentary barite. Environ Toxicol Chem 2015;34:507–517. © 2014 SETAC
Hippocampal dendritic spines remodeling and fear memory are modulated by GABAergic signaling within the basolateral amygdala complex
Authors: Giachero Marcelo , Calfa Gaston D. , Molina Victor A.
Published: January 2015

GABAergic signaling in the basolateral amygdala complex (BLA) plays a crucial role on the modulation of the stress influence on fear memory. Moreover, accumulating evidence suggests that the dorsal hippocampus (DH) is a downstream target of BLA neurons in contextual fear. Given that hippocampal structural plasticity is proposed to provide a substrate for the storage of long‐term memories, the main aim of this study is to evaluate the modulation of GABA neurotransmission in the BLA on spine density in the DH following stress on contextual fear learning. The present findings show that prior stressful experience promoted contextual fear memory and enhanced spine density in the DH. Intra‐BLA infusion of midazolam, a positive modulator of GABAa sites, prevented the facilitating influence of stress on both fear retention and hippocampal dendritic spine remodeling. Similarly to the stress‐induced effects, the blockade of GABAa sites within the BLA ameliorated fear memory emergence and induced structural remodeling in the DH. These findings suggest that GABAergic transmission in BLA modulates the structural changes in DH associated to the influence of stress on fear memory. © 2015 Wiley Periodicals, Inc.
Rainfall as dominant driver of rotifer dynamics in shallow wetlands: Evidence from a long‐term data record (Upo Wetlands, South Korea)
Authors: Choi Jong‐Yun , Jeong Kwang‐Seuk , Joo Gea‐Jae
Published: January 2015

In this study, we explain the environmental variables that mainly influence the seasonal pattern of rotifer communities in shallow wetlands (Upo Wetlands, South Korea). Long‐term data (n = 197, 2006–2013) were used to analyze the patterns by means of a self‐organizing map (SOM), which extracts information through competitive and adaptive properties. A total of 32 variables (24 groups of rotifers and 8 environmental variables) were patterned onto the SOM, and then each variable was compared in accordance with four seasonal patterns. Three clusters were categorized according to the Euclidian distance between the clusters on the SOM, and these were interpreted in relation to seasonal features. Using the SOM, the rotifer groups were clearly distinguished by water temperature and rainfall. In particular, pelagic rotifer groups (Brachionus, Keratella, and Polyarthra) were less abundant when high rainfall occurred, but epiphytic rotifers (Lepadella, Leacne, and Monostyla) were strongly associated with high rainfall. Moreover, strong rainfall occurring on several consecutive days increased the rotifer abundance on macrophytes. The SOM results depicted a clear pattern of rotifer density clusters partitioned by rainfall, which determined the seasonal distribution of rotifer groups in a shallow wetland.
Investigation of the pruritus‐induced functional activity in the rat brain using manganese‐enhanced MRI
Authors: Jeong Keun‐Yeong , Kang Ji‐Hyuk
Published: December 2014

Purpose

To provide clear information on the activation regions of itching, we investigated the functional activity of cerebral regions in the pruritus‐induced rat model using manganese‐enhanced magnetic resonance imaging (MEMRI).

Materials and Methods

Itching was induced via neonatal capsaicin treatment in Sprague‐Dawley rats (itching rats), and scratching behavior of the control, itching, and gabapentin (GBP)‐treated itching rats was compared. Then the activated or deactivated brain regions were investigated in the control, itching, and GBP‐treated itching rats using a 4.7T MRI system.

Results

While the itching rats engaged in vigorous scratching (121.2 ± 22.4 times), the scratching behavior was decreased in the GBP‐treated itching rats (30.6 ± 8.8 times). GBP induced the attenuation of functional activity in two regions −7.10 mm from bregma, in one region −6.65 mm from bregma, and in one region −6.06 mm from bregma. The brain regions related to itching were as follows: parafascicular nucleus, thalamus, superior/inferior colliculus, periaqueductal gray, cingulate cortex, amygdala, midbrain regions, lateral habenula, and hypothalamic areas.

Conclusion

Our MEMRI investigation indicates new functional activity of cerebral regions in rats due to the effect of itching or GBP. This information could be used to monitor the therapeutic effects of novel agents or for clinical strategies to treat pathological itch. J. Magn. Reson. Imaging 2015;42:709–716.
Multiyear greenhouse gas flux measurements on a temperate fen soil used for cropland or grassland
Authors: Beyer Colja , Liebersbach Horst , Höper Heinrich
Published: January 2015

To date there is still a lack of reliable data on greenhouse gas emissions from drained fens needed to determine the climatic relevance of land use and land use change on peatlands and to supply the National Inventory Report for the German Greenhouse Gas Inventory. In this study we present the results of monthly‐based multiyear measurements of CO2, N2O and CH4 flux rates in two drained agriculturally used fen ecosystems in NW Germany (cropland and grassland) over a period of 4.5 y using transparent and opaque closed chambers. CO2 exchange was modelled at high resolution with temperature and photosynthetic active radiation. The measured and modelled values fit very well (R2 ≥ 0.93). Annual GHG and Global Warming Potential (GWP) balances were determined. Net CO2 emissions at the cropland and grassland sites were similarly high, taking into account changes in management; net ecosystem C balance amounted to about 4.0 to 5.0 Mg C ha−1 y−1. Emissions of N2O and CH4 were low at both sites. The mean GWP balance for a time frame of 100 y (GWP100) amounted to about 17.0 to 19.0 Mg CO2‐eq. ha−1 y−1. The unexpectedly low greenhouse gas emissions from the cropland site are attributed to the high water table and a change in crop management. The change from corn for silage to corn‐cob mix lead transiently to rather small greenhouse gas emissions. The study confirms the need for multiyear measurements taking climatic and management variation into account.
Engineering of a thermostable β‐1,3‐1,4‐glucanase from Bacillus altitudinisYC‐9 to improve its catalytic efficiency
Authors: Mao Shurui , Gao Peng , Lu Zhaoxin , Lu Fengxia , Zhang Chong , Zhao Haizhen , Bie Xiaomei
Published: December 2014

BACKGROUND

Error‐prone polymerase chain reaction (PCR) is frequently used in directed evolution of enzymes to modify their quality. In this study, error‐prone PCR was used to improve the catalytic efficiency of β‐1,3‐1,4‐glucanase from Bacillus altitudinis YC‐9.

RESULTS

By screening, the mutant Glu‐3060 with higher activity was selected among 5000 transformants. After induction with isopropyl β‐d‐1‐thiogalactopyranoside (IPTG), the activity of the mutant Glu‐3060 reached 474.6 U mL−1, resulting in a 48.6% increment of the parent enzyme activity. Research on the characterization of the mutated enzyme showed the optimal pH of the mutated enzyme to be 5.0, which is lower than the parent enzyme, but thermal stability was almost the same between them. Sequence analysis of the mutated enzyme revealed that three amino acids were changed compared with the parent enzyme, including K142N, Q203L and N214D.

CONCLUSION

The three‐dimensional structure predicted by SWISS‐MODEL of the mutated enzyme Glu‐3060 showed that the substitution of three amino acids had an effect on the catalytic activity, stability and optimal pH of the enzyme, through changing the charge properties or electron density, forming secondary keys, the acidity of the amino acids and the side chain group. The sum effects of all the factors were increased activity of the mutated enzyme and decreased optimal pH, while the same thermostability was maintained, thereby increasing the suitability of the enzyme for industrial use. © 2014 Society of Chemical Industry
Modeling risk of pneumonia epizootics in bighorn sheep
Authors: Sells Sarah N. , Mitchell Michael S. , Nowak J. Joshua , Lukacs Paul M. , Anderson Neil J. , Ramsey Jennifer M. , Gude Justin A. , Krausman Paul R.
Published: January 2015

Pneumonia epizootics are a major challenge for management of bighorn sheep (Ovis canadensis) affecting persistence of herds, satisfaction of stakeholders, and allocations of resources by management agencies. Risk factors associated with the disease are poorly understood, making pneumonia epizootics hard to predict; such epizootics are thus managed reactively rather than proactively. We developed a model for herds in Montana that identifies risk factors and addresses biological questions about risk. Using Bayesian logistic regression with repeated measures, we found that private land, weed control using domestic sheep or goats, pneumonia history, and herd density were positively associated with risk of pneumonia epizootics in 43 herds that experienced 22 epizootics out of 637 herd‐years from 1979–2013. We defined an area of high risk for pathogen exposure as the area of each herd distribution plus a 14.5‐km buffer from that boundary. Within this area, the odds of a pneumonia epizootic increased by >1.5 times per additional unit of private land (unit is the standardized % of private land where global  = 25.58% and SD = 14.53%). Odds were >3.3 times greater if domestic sheep or goats were used for weed control in a herd's area of high risk. If a herd or its neighbors within the area of high risk had a history of a pneumonia epizootic, odds of a subsequent pneumonia epizootic were >10 times greater. Risk greatly increased when herds were at high density, with nearly 15 times greater odds of a pneumonia epizootic compared to when herds were at low density. Odds of a pneumonia epizootic also appeared to decrease following increased spring precipitation (odds = 0.41 per unit increase, global  = 100.18% and SD = 26.97%). Risk was not associated with number of federal sheep and goat allotments, proximity to nearest herds of bighorn sheep, ratio of rams to ewes, percentage of average winter precipitation, or whether herds were of native versus mixed or reintroduced origin. We conclude that factors associated with risk of pneumonia epizootics are complex and may not always be from the most obvious sources. The ability to identify high‐risk herds will help biologists and managers determine where to focus management efforts and the risk factors that most affect each herd, facilitating more effective, proactive management. © 2015 The Wildlife Society.
Is the OSA‐18 predictive of obstructive sleep apnea: Comparison to polysomnography
Authors: Ishman Stacey L. , Yang Christina J. , Cohen Aliza P. , Benke James R. , Meinzen‐Derr Jareen K. , Anderson Rebecca M. , Madden Marie E. , Tabangin Meredith E.
Published: December 2014

Objectives/Hypothesis

To examine the ability of the OSA−18 to predict Obstructive Sleep Apnea (OSA) in a racially diverse population when compared to overnight polysomnography (PSG).

Study Design

Cross‐sectional retrospective.

Methods

Children 2 to 12 years of age diagnosed with OSA who were treated at a tertiary care institution between 2008 and 2013 and had complete PSG and OSA‐18 data were included. We performed logistic regression with OSA as the dependent variable and the OSA‐18 total symptom score (TSS), age, gender, race, asthma, and body mass index (BMI) as independent variables.

Results

Seventy‐nine children (32 females) were included (mean age 5.2 ± 2.4 years). The positive predictive value (PPV) was greater than 90 for an obstructive apnea–hypopnea index (oAHI) ≥ 1. The PPV and specificity were higher for white than for nonwhite children; however, sensitivity and negative predictive value (NPV) of OSA‐18 TSS were low for mild, moderate, and severe OSA regardless of race. Age, race, and BMI were not significantly associated with oAHI.

Conclusions

This study, conducted in a racially diverse cohort, examined the ability of the OSA‐18 to predict OSA when compared to PSG—the gold standard—and found that sensitivity and NPV were extremely low for both white and nonwhite children. This suggests that the OSA‐18 is not sufficiently sensitive to detect OSA nor sufficiently specific to determine the absence of OSA. The OSA‐18 should be used as a quality‐of‐life indicator and is not a reliable substitute for PSG.

Level of Evidence

4. Laryngoscope, 125:1491–1495, 2015