bluuebunny/crossref_metadata_2025_split huggingface dataset:
Real‐time Monitoring of Discrete Synaptic Release Events and Excitatory Potentials within Self‐reconstructed Neuromuscular Junctions
Authors: Li Yu‐Tao , Zhang Shu‐Hui , Wang Xue‐Ying , Zhang Xin‐Wei , Oleinick Alexander I. , Svir Irina , Amatore Christian , Huang Wei‐Hua 
Published: June 2015

AbstractChemical synaptic transmission is central to the brain functions. In this regard, real‐time monitoring of chemical synaptic transmission during neuronal communication remains a great challenge. In this work, in vivo‐like oriented neural networks between superior cervical ganglion (SCG) neurons and their effector smooth muscle cells (SMC) were assembled in a microfluidic device. This allowed amperometric detection of individual neurotransmitter release events inside functional SCG‐SMC synapse with carbon fiber nanoelectrodes as well as recording of postsynaptic potential using glass nanopipette electrodes. The high vesicular release activities essentially involved complex events arising from flickering fusion pores as quantitatively established based on simulations. This work allowed for the first time monitoring in situ chemical synaptic transmission under conditions close to those found in vivo, which may yield important and new insights into the nature of neuronal communications.
Graphene‐Based Photocatalysts for Solar‐Fuel Generation
Authors: Xiang Quanjun , Cheng Bei , Yu Jiaguo 
Published: June 2015

AbstractThe production of solar fuel through photocatalytic water splitting and CO2 reduction using photocatalysts has attracted considerable attention owing to the global energy shortage and growing environmental problems. During the past few years, many studies have demonstrated that graphene can markedly enhance the efficiency of photocatalysts for solar‐fuel generation because of its unique 2D conjugated structure and electronic properties. Herein we summarize the recent advances in the application of graphene‐based photocatalysts for solar‐fuel production, including CO2 reduction to hydrocarbon fuel and water splitting to H2. A brief overview of the fundamental principles for splitting of water and reduction of CO2 is given. The different roles of graphene in these graphene‐based photocatalysts for improving photocatalytic performance are discussed. Finally, the perspectives on the challenges and opportunities for future research in this promising area are also presented.
Complex Functional Systems with Three Different Types of Dynamic Covalent Bonds
Authors: Zhang Kang‐Da , Matile Stefan 
Published: June 2015

AbstractMulticomponent surface architectures are introduced that operate with three different dynamic covalent bonds. Disulfide exchange under basic conditions accounts for the growth of π stacks on solid surfaces. Hydrazone exchange under acidic conditions is used to add a second coaxial string or stack, and boronic ester exchange under neutral conditions is used to co‐align a third one. The newly introduced boronic ester exchange chemistry is compatible with stack and string exchange without interference from the orthogonal hydrazone and disulfide exchange. The functional relevance of surface architectures with three different dynamic covalent bonds is exemplified with the detection of polyphenol natural products, such as epigallocatechin gallate, in competition experiments with alizarin red. These results describe synthetic strategies to create functional systems of unprecedented sophistication with regard to dynamic covalent chemistry.
Chemical Ligation and Isotope Labeling to Locate Dynamic Effects during Catalysis by Dihydrofolate Reductase
Authors: Luk Louis Y. P. , Ruiz‐Pernía J. Javier , Adesina Aduragbemi S. , Loveridge E. Joel , Tuñón Iñaki , Moliner Vincent , Allemann Rudolf K. 
Published: June 2015

AbstractChemical ligation has been used to alter motions in specific regions of dihydrofolate reductase from E. coli and to investigate the effects of localized motional changes on enzyme catalysis. Two isotopic hybrids were prepared; one with the mobile N‐terminal segment containing heavy isotopes (2H, 13C, 15N) and the remainder of the protein with natural isotopic abundance, and the other one with only the C‐terminal segment isotopically labeled. Kinetic investigations indicated that isotopic substitution of the N‐terminal segment affected only a physical step of catalysis, whereas the enzyme chemistry was affected by protein motions from the C‐terminal segment. QM/MM studies support the idea that dynamic effects on catalysis mostly originate from the C‐terminal segment. The use of isotope hybrids provides insights into the microscopic mechanism of dynamic coupling, which is difficult to obtain with other studies, and helps define the dynamic networks of intramolecular interactions central to enzyme catalysis.
Optimization of a heat‐tolerant β‐glucosidase production by Bacillus sp. ZJ1308 and its purification and characterization
Authors: Xu Zhenni , Zhang Lei , Yu Ping 
Published: June 2015

AbstractResponse surface methodology was used to optimize the medium composition to improve the production of the heat‐tolerant β‐glucosidase from Bacillus sp. ZJ1308. Three significant factors were found to be corn cob, beef extract, and MnSO4·H2O. The final medium compositions optimized were corn cob (51.8 g/L), beef extract (23.8 g/L), salicin (0.5 g/L), MnSO4·H2O (0.363 g/L), MgSO4·7H2O (0.4 g/L), and NaCl (5 g/L). Under the optimal conditions, the activity of β‐glucosidase was up to 4.71 U/mL. β‐Glucosidase was purified to homogeneity with a recovery rate of 5% and a specific activity of 110.47 U/mg. The optimal pH and temperature were 7.0 and 60 °C, respectively. β‐Glucosidase was stable within a pH range of 6.0–8.0 and showed an extremely high thermostability at 80 and 90 °C, retaining 56% and 38% of its maximal activity, respectively. Ni2+ and Ba2+ heavily inhibited the β‐glucosidase activity. The purified β‐glucosidase showed a high substrate specificity. The kinetic parameters revealed that it had a high catalytic efficiency toward the substrate p‐nitrophenyl‐β‐d‐glucopyranoside (Kcat/Km = 700). It also showed a high catalytic activity toward the natural substrate salicin. This study provides a new insight into the future development and use of β‐glucosidase from Bacillus sp. ZJ1308.
Defect‐Rich CoP/Nitrogen‐Doped Carbon Composites Derived from a Metal–Organic Framework: High‐Performance Electrocatalysts for the Hydrogen Evolution Reaction
Authors: Zhang Zhe , Hao Jinhui , Yang Wenshu , Tang Jilin 
Published: June 2015

AbstractA defect‐rich CoP/nitrogen‐doped carbon composite is reported for the first time derived from ZIF‐67 by means of low‐temperature phosphidation process. As a hydrogen evolution reaction electrocatalyst, the obtained CoP‐N‐C has high HER activity and good stability with a low onset overpotential of 31 mV, a small Tafel slope of 42 mV dec−1, a large exchange current density of 1.6×10−1 mA cm−2, and a 10 mA cm−2 current density at overpotential 91 mV.
Chaotic Analysis of the Concentration Field in a Submerged Impinging Stream Mixer
Authors: Zhang Jianwei , Dong Xin , Ma Hongyue , Li Xiaoming , Feng Ying 
Published: June 2015

AbstractThe concentration field was measured with various nozzle diameters, nozzle distances, and inlet flow rates in a submerged impinging stream mixer (SISM) using planar laser‐induced fluorescence to obtain characteristic parameters such as correlation dimension, Kolmogorov entropy, and Lyapunov exponents that describe the chaos phenomenon and reflect the microcosmic mixture effect of a SISM by mean of the chaos theory. The chaotic characteristic parameters were influenced significantly by different nozzles distances, nozzle diameters, and inlet flow rates and their distributions followed a similar changing regularity by which all parameters decreased with larger nozzle diameter and increased with higher inlet flow rate.
Explicit Determinations of the Colebrook Equation for the Flow Friction Factor by Statistical Analysis
Authors: Heydari Amir , Narimani Elhameh , Pakniya Fatemeh 
Published: June 2015

AbstractThe implicit Colebrook equation is considered as a fundamental equation for estimating the friction factor for turbulent flows in pipes. A large number of simple and accurate explicit approximations cover just a limited area of turbulent regime inside rough or smooth pipes. Here, three explicit approximations of the friction factor were determined. The friction factor data were fitted into polynomials using the response surface design of Minitab® software. To reduce the relative error of the first approximation compared with the implicit Colebrook equation, the domain was divided into two regions based on the Reynolds number (Re). To compare the accuracy and complexity of the approximations with existing relations, advanced comparison analysis based on the relative error was performed. The second set of approximations defined in two ranges of Re demonstrated high accuracy and a satisfying complexity index.
Chemoproteomic Evaluation of the Polyacetylene Callyspongynic Acid
Authors: Nickel Sabrina , Serwa Remigiusz A. , Kaschani Farnusch , Ninck Sabrina , Zweerink Susanne , Tate Edward W. , Kaiser Markus 
Published: June 2015

AbstractPolyacetylenes are a class of alkyne‐containing natural products. Although potent bioactivities and thus possible applications as chemical probes have already been reported for some polyacetylenes, insights into the biological activities or molecular mode of action are still rather limited in most cases. To overcome this limitation, we describe the application of the polyacetylene callyspongynic acid in the development of an experimental roadmap for characterizing potential protein targets of alkyne‐containing natural products. To this end, we undertook the first chemical synthesis of callyspongynic acid. We then used in situ chemical proteomics methods to demonstrate extensive callyspongynic acid‐mediated chemical tagging of endoplasmic reticulum‐associated lipid‐metabolizing and modifying enzymes. We anticipate that an elucidation of protein targets of natural products may serve as an effective guide to the development of subsequent biological assays that aim to identify chemical phenotypes and bioactivities.
A novel acoustically quiet coil for neonatal MRI system
Authors: Ireland Christopher M. , Giaquinto Randy O. , Loew Wolfgang , Tkach Jean A. , Pratt Ronald G. , Kline‐Fath Beth M. , Merhar Stephanie L. , Dumoulin Charles L. 
Published: June 2015

ABSTRACTMagnetic resonance imaging (MRI) acoustic exposure has the potential to elicit physiological distress and impact development in preterm and term infants. To mitigate this risk, a novel acoustically quiet coil was developed to reduce the sound pressure level experienced by neonates during MR procedures. The new coil has a conventional high‐pass birdcage radio frequency design, but is built on a framework of sound abating material. We evaluated the acoustic and MR imaging performance of the quiet coil and a conventional body coil on two small footprint neonatal intensive care unit MRI systems. Sound pressure level and frequency response measurements were made for six standard clinical MR imaging protocols. The average sound pressure level, reported for all six imaging pulse sequences, was 82.2 dBA for the acoustically quiet coil, and 91.1 dBA for the conventional body coil. The sound pressure level values measured for the acoustically quiet coil were consistently lower, 9 dBA (range 6–10 dBA) quieter on average. The acoustic frequency response of the two coils showed a similar harmonic profile for all imaging sequences. However, the amplitude was lower for the quiet coil, by as much as 20 dBA. © 2015 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 45B: 107–114, 2015
Effective clinical practices for improved FNA biopsy cell block outcomes
Authors: Collins Brian T. , Garcia Telly C. , Hudson Jena B. 
Published: June 2015

BACKGROUNDCell blocks are critically important in fine‐needle aspiration (FNA) biopsies and the increasing requirements for personalized medicine testing further highlight their value. When a cell block is inadequate, it can necessitate additional procedures. The objective of the current study was to measure the impact and outcome of dedicated aspirate pass techniques and slide cellularity on cell block quality.METHODSOver a 6‐month period, all FNA biopsy cases with cell blocks were identified. Procedural data including the number of dedicated aspirate passes were recorded. Individual cases were retrospectively reviewed and scored for multiple endpoints, including aspirate smear cellularity and cell block quality.RESULTSA total of 605 FNA biopsy and cell block cases were identified. The cell block quality score demonstrated a progressive improvement with an increasing number of dedicated biopsies. The performance of a single dedicated biopsy demonstrated a higher percentage of intermediate to high cell block quality scores in comparison with none (+12.1%; P = .0142). The performance of 3 dedicated biopsies demonstrated a higher percentage of intermediate to high cell block quality scores in comparison with a single pass (+13.5%; P = .0138). An intermediate‐quality to high‐quality terminal aspirate smear was more likely to have a high cell block quality score (+31.6%; P = .0001).CONCLUSIONSPerforming at least 1 dedicated FNA biopsy pass was found to improve cell block quality and multiple dedicated biopsies resulted in nearly one‐half having a higher quality score. A high‐cellularity terminal FNA biopsy smear contributed significantly to obtaining a high‐quality cell block. Performing dedicated FNA biopsies and the use of high‐quality aspirate smears are effective clinical practices for improving cell block outcomes. Cancer (Cancer Cytopathol) 2015;123:540–547. © 2015 American Cancer Society.
Growth of Two‐Dimensional Metal–Organic Framework Nanosheet Crystals on Graphite Substrates by Thermal Equilibrium Treatment in Acetic Acid Vapor
Authors: Sakata Kouhei , Kashiyama Soichiro , Matsuo Gento , Uemura Shinobu , Kimizuka Nobuo , Kunitake Masashi 
Published: June 2015

AbstractLarge two‐dimensional (2D) nanosheets of crystalline coordination frameworks were prepared on highly oriented pyrolytic graphite (HOPG) by re‐crystallization induced by thermal equilibrium treatment in acetic acid vapor. The nanosheets comprised 5,10,15,20‐tetrakis(4‐carboxyphenyl)‐porphyrin (H2TCPP) cross‐linked by copper ions. We found that an acetic acid vapor environment dramatically decreased the activation energy and accelerated the recombination of coordination bonds between metal ions and carboxylate ligands in the H2TCPP‐Cu frameworks. Ultimately, two‐dimensional horizontal crystal growth was induced to form monomolecular sheets as the most thermodynamically stable crystal structure on a well‐defined surface.
The Role of miR‐21 in Cancer
Authors: Pfeffer Susan R. , Yang Chuan He , Pfeffer Lawrence M. 
Published: June 2015

ABSTRACT

Preclinical Research

MicroRNAs (miRNAs) are small endogenous noncoding RNAs that suppress gene expression at the post‐transcriptional level. In the past decade, miRNAs have been extensively studied in a number of different human cancers. MiRNAs have been identified to act both as oncogenes and as tumor suppressors. In addition, miRNAs are associated with the intrinsic resistance of cancer to various forms of therapy, and they are implicated in both tumor progression and metastasis. The characterization of the specific alterations in the patterns of miRNA expression in cancer has great potential for identifying biomarkers for early cancer detection, as well as for potential therapeutic intervention in cancer treatment. In this chapter, we describe the ever‐expanding role of miR‐21 and its target genes in different cancers, and provide insight into how this oncogenic miRNA regulates cancer cell proliferation, migration, and apoptosis by suppressing the expression of tumor suppressors. Drug Dev Res 76 : 270–277, 2015. © 2015 Wiley Periodicals, Inc.
New approach for vitamin E extraction in rainbow trout flesh: Application in fish fed commercial and red seaweed‐supplemented diets
Authors: Araújo Mariana , Alves Rita C. , Pimentel Filipa B. , Costa Anabela S.G. , Fernandes Telmo J.R. , Valente Luísa M.P. , Rema Paulo , Oliveira M. Beatriz P.P. 
Published: June 2015

A vitamin E extraction method for rainbow trout flesh was optimized, validated, and applied in fish fed commercial and Gracilaria vermiculophylla‐supplemented diets. Five extraction methods were compared. Vitamers were analyzed by HPLC/DAD/fluorescence. A solid‐liquid extraction with n‐hexane, which showed the best performance, was optimized and validated. Among the eight vitamers, only α‐ and γ‐tocopherol were detected in muscle samples. The final method showed good linearity (>0.999), intra‐ (<3.1%) and inter‐day precision (<2.6%), and recoveries (>96%). Detection and quantification limits were 39.9 and 121.0 ng/g of muscle, for α‐tocopherol, and 111.4 ng/g and 337.6 ng/g, for γ‐tocopherol, respectively. Compared to the control group, the dietary inclusion of 5% G. vermiculophylla resulted in a slight reduction of lipids in muscle and, consequently, of α‐ and γ‐tocopherol. Nevertheless, vitamin E profile in lipids was maintained. In general, the results may be explained by the lower vitamin E level in seaweed‐containing diet.Practical Applications: Based on the validation results and the low solvent consumption, the developed method can be used to analyze vitamin E in rainbow trout. The results of this work are also a valuable information source for fish feed industries and aquaculture producers, which can focus on improving seaweed inclusion in feeds as a source of vitamin E in fish muscle and, therefore, take full advantage of all bioactive components with an important role in fish health and flesh quality.Muscle samples from rainbow trout fed a commercial diets were used to select, optimize, and validate an extraction method for vitamin E. The final method was used to extract α and γ‐tocopherol in muscle from rainbow trout fed a control (CTRL) and a seaweed‐supplemented diet (GRA).
A Tris(hydroxymethyl)aminomethane‐Rhodamine Spirolactam Derivative as Dual Channel pH and Water Sensor and Its Application to Bio Imaging
Authors: Devi Manisha , Dhir Abhimanew , Pradeep Chullikkattil P. 
Published: June 2015

AbstractA rhodamine spirolactam derivative, R1, having tris(hydroxymethyl)aminomethane moiety as substituent on the spirolactam ring has been synthesized and characterized. R1 shows visual colour change and fluorescence in protic solvents and it is capable of sensing trace amounts of water present in organic solvents. In addition, R1 shows reversible ON–OFF switching in its fluorescence and absorption properties as a function of solution pH. Different from majority of the reported rhodamine spirolactam derivatives, R1 shows strong fluorescence and absorption over a wide pH range (pH 3–9) and on either side of this range, it gets converted into colourless and non‐fluorescent ring closed form. The reversible ring opening and ring closure of R1 as a function of solution pH have been supported by spectroscopic analyses. We also demonstrate the potential use of R1 in cell imaging as it stains selectively the nucleus of Allium cepa root tip cells and human white blood cells (WBCs) at lower concentrations.
Vertical earthquake response of megawatt‐sized wind turbine with soil‐structure interaction effects
Authors: Kjørlaug Remi A. , Kaynia Amir M. 
Published: June 2015

SummaryThe dynamic response of a wind turbine on monopile is studied under horizontal and vertical earthquake excitations. The analyses are carried out using the finite element program SAP2000. The finite element model of the structure is verified against the results of shake table tests, and the earthquake response of the soil model is verified against analytical solutions of the steady‐state response of homogeneous strata. The focus of the analyses in this paper is the vertical earthquake response of wind turbines including the soil‐structure interaction effects. The analyses are carried out for both a non‐homogeneous stratum and a deep soil using the three‐step method. In addition, a procedure is implemented which allows one to perform coupled soil‐structure interaction analyses by properly tuning the damping in the tower structure. The analyses show amplification of the ground surface acceleration to the top of the tower by a factor of two. These accelerations are capable of causing damage in the turbine and the tower structure, or malfunctioning of the turbine after the earthquake; therefore, vertical earthquake excitation is considered a potential critical loading in design of wind turbines even in low‐to‐moderate seismic areas. Copyright © 2015 John Wiley & Sons, Ltd.
Daytime somnolence as an early sign of cognitive decline in a community‐based study of older people
Authors: Tsapanou Angeliki , Gu Yian , O'Shea Deirdre , Eich Teal , Tang Ming‐Xin , Schupf Nicole , Manly Jennifer , Zimmerman Molly , Scarmeas Nikolaos , Stern Yaakov 
Published: June 2015

ObjectiveThis study aimed to examine the association between self‐reported sleep problems and cognitive decline in community‐dwelling older people. We hypothesized that daytime somnolence predicts subsequent cognitive decline.MethodsThis is a longitudinal study in a 3.2‐year follow‐up, with 18‐month intervals. The setting is the Washington Heights‐Inwood Community Aging Project. There were 1098 participants, who were over 65 years old and recruited from the community.Sleep problems were estimated using five sleep categories derived from the RAND Medical Outcome Study Sleep Scale: sleep disturbance, snoring, awaken short of breath/with a headache, sleep adequacy, and daytime somnolence. Four distinct cognitive composite scores were calculated: memory, language, speed of processing, and executive functioning. We used generalized estimating equations analyses with cognitive scores as the outcome, and time, sleep categories and their interactions as the main predictors. Models were initially unadjusted and then adjusted for age, gender, education, ethnicity, depression, and apolipoprotein E‐ε4 genotype.ResultsIncreased daytime somnolence (including feeling drowsy/sleepy, having trouble staying awake, and taking naps during the day) was linked to slower speed of processing both cross‐sectionally (B = −0.143, p = 0.047) and longitudinally (B = −0.003, p = 0.027). After excluding the demented participants at baseline, the results remained significant (B = −0.003, p = 0.021).ConclusionsOur findings suggest that daytime somnolence may be an early sign of cognitive decline in the older population. Copyright © 2015 John Wiley & Sons, Ltd.