bluuebunny/crossref_metadata_2025_split huggingface dataset:
Performance of fiber delay‐line buffers in asynchronous packet‐based optical switching networks with wavelength conversion
Authors: Zhang Tao , Wang Jin 
Published: January 2014

SummaryA major challenge in asynchronous packet‐based optical networks is packet contention, which occurs when two or more packets head to the same output at the same time. To resolve contention in the optical domain, two primary approaches are wavelength conversion and fiber delay line (FDL) buffering. In wavelength conversion, a contending packet can be converted from one wavelength to another in order to avoid conflict. In FDL buffering, contending packets can be delayed for a fixed amount of time. While the performance of wavelength conversion and FDL buffering has been evaluated extensively in synchronous networks with fixed‐sized packets, in this paper, we study the performance of FDL buffers in asynchronous packet‐based optical networks with wavelength conversion. An analytical model is proposed to evaluate the performance in terms of packet loss probability and average delay. Extensive simulation and analytical results show that, with appropriate settings, FDL buffers can perform much better in switches with wavelength conversion than in switches with no conversion. Copyright © 2014 John Wiley & Sons, Ltd.
Electronic and Steric Effects of the Peripheral Substitution in Deca‐ and Undecaaryl Metallocorroles
Authors: Gao Di , Canard Gabriel , Giorgi Michel , Vanloot Pierre , Balaban Teodor Silviu 
Published: January 2014

AbstractInvited for the cover of this issue are chemists from the University of Aix Marseille, France. The cover image shows the saddling of the aromatic corrole macrocycle that occurs when the cavity of the corrole is metallated with a copper ion. This saddling is reinforced by bulky peripheral aryl groups, which modulate the electrochemical properties of deca‐ and undecaaryl copper corroles. The background is a view of the autonomous port of Marseille.
Human mitochondrial leucyl tRNA synthetase can suppress non cognate pathogenic mt‐tRNA mutations
Authors: Hornig‐Do Hue Tran , Montanari Arianna , Rozanska Agata , Tuppen Helen A , Almalki Abdulraheem A , Abg‐Kamaludin Dyg P , Frontali Laura , Francisci Silvia , Lightowlers Robert N , Chrzanowska‐Lightowlers Zofia M 
Published: January 2014

AbstractDisorders of the mitochondrial genome cause a wide spectrum of disease, these present mainly as neurological and/or muscle related pathologies. Due to the intractability of the human mitochondrial genome there are currently no effective treatments for these disorders. The majority of the pathogenic mutations lie in the genes encoding mitochondrial tRNAs. Consequently, the biochemical deficiency is due to mitochondrial protein synthesis defects, which manifest as aberrant cellular respiration and ATP synthesis. It has previously been reported that overexpression of mitochondrial aminoacyl tRNA synthetases has been effective, in cell lines, at partially suppressing the defects resulting from mutations in their cognate mt‐tRNAs. We now show that leucyl tRNA synthetase is able to partially rescue defects caused by mutations in non‐cognate mt‐tRNAs. Further, a C terminal peptide alone can enter mitochondria and interact with the same spectrum of mt‐tRNAs as the entire synthetase, in intact cells. These data support the possibility that a small peptide could correct at least the biochemical defect associated with many mt‐tRNA mutations, inferring a novel therapy for these disorders.
The use of a Corophium volutator chronic sediment study to support the risk assessment of medetomidine for marine environments
Authors: Fox Michelle , Ohlauson Cecilia , Sharpe Alan D. , Brown Rebecca J. 
Published: January 2014

Abstract

Chronic sediment studies were conducted using the marine amphipod Corophium volutator as part of an environmental risk assessment of the novel antifouling compound medetomidine. Two studies were performed, starting with neonates of less than 7 d old. A 28-d study considered endpoints of survival and growth (length and wet wt) and a 76-d study looked at survival, growth (length and wet wt), and reproduction (number of gravid females and neonates). Medetomidine was dosed via the sediment at nominal test concentrations of 1.0 µg/kg, 3.2 µg/kg, 10 µg/kg, 32 µg/kg, and 100 µg/kg (dry wt). In the 28-d growth study, a significant increase in mortality was observed at 32 µg/kg and 100 µg/kg. In the 76-d reproduction study, there were significant adverse effects on survival (32 µg/kg and 100 µg/kg), growth (100 µg/kg), and reproduction (100 µg/kg). The overall lowest-observed-effect concentration was 32 µg/kg medetomidine. For this test substance the increased study duration did not increase the overall sensitivity of the test. The present study suggests that the predicted sediment environmental concentration (PECsediment) of 0.003 µg/kg for medetomidine would not be expected to cause adverse effects on the life history of C. volutator. Environ Toxicol Chem 2014;33:937–942. © 2014 SETAC
Effects of 17β-estradiol pollution on water microbial methane oxidation activity
Authors: Ruan Aidong , Zong Fengjiao , Zhao Ying , Liu Chenxiao , Chen Jing 
Published: January 2014

Abstract

17β-estradiol (17β-E2), a widespread and natural estrogen in the environment, has imposed a serious threat to the safety and function of aquatic ecosystems because of worsening pollution and high potential toxicity. In the present study, the authors focus on the impact of 17β-E2 pollution on water microbial methane oxidation function. The authors investigated the mechanism of its influence on water microbial activity and discuss the growth rate of methane-oxidizing bacteria. The results showed that 17β-E2 could significantly inhibit the function of water microbial methane oxidation. When 17β-E2 concentration was ≥5 ng L−1, the methane oxidation rate increased with increasing 17β-E2 and finally settled to a constant value. Furthermore, the authors found no significant linear correlation between 17β-E2 concentrations and its methane oxidation rate. However, increasing 17β-E2 dramatically improved water microbial community activity, because a significant or highly significant promotion in the generation rate of CO2 was measured. Moreover, within a certain period of time and at certain concentrations, positive linear correlation existed between water CO2 generation rate and 17β-E2 concentrations. In addition, the growth rate of culturable methane-oxidizing bacteria was promoted when 17β-E2 pollution concentration from 2 ng L−1 to 20 ng L−1. Therefore, 17β-E2 pollution can inhibit microbial methane oxidation function in water, which indirectly promotes the release of water methane and directly contributes to the rate of water-generated and released CO2. Specifically, 17β-E2 pollution can promote water emissions of greenhouse gases. Environ Toxicol Chem 2014;33:768–775. © 2014 SETAC
Tanshinone II A Inhibits Tat‐Induced HIV‐1 Transactivation Through Redox‐Regulated AMPK/Nampt Pathway
Authors: Zhang Hong‐Sheng , Chen Xin‐Yu , Wu Tong‐Chao , Zhang Feng‐Juan 
Published: January 2014

AbstractTat transactivating activity regulated by NAD+‐dependent histone deacetylase sirtuin1 (SIRT1) connects HIV transcription with the metabolic state of the cell. Nicotinamide phosphoribosyltransferase (Nampt) is a rate‐limiting enzyme in the mammalian NAD+ biosynthesis. Nampt, SIRT1, and AMPK were involved in inhibiting HIV‐1 transactivation through redox‐regulated pathway. Tanshinone II A is a main lipid‐soluble monomer derivative from the root of Salvia miltiorrhiza (Danshen) and tanshinone II A possess a variety of biological activities through redox signaling pathway. Here we investigated the effect of tanshinone II A on Tat‐induced HIV‐1 transactivation and the redox signaling pathway involved in it. As the results were shown, tanshinone II A reversed Tat‐induced reactive oxygen species (ROS) production and down‐regulation of glutathione (GSH) levels in TZM‐bl cells through up‐regulation of Nrf2 expression. Tanshinone II A reversed Tat‐induced inhibition of SIRT1 activity but not SIRT1 protein expression. Tanshinone II A reversed Tat‐induced inhibition of Nampt protein expression and depletion of NAD+ levels in TZM‐bl cells in a dose‐dependent manner. Tanshinone II A‐evoked Nampt expression was mediated by AMPK signaling pathway. Tanshinone II A inhibited Tat‐induced HIV‐1 LTR transactivation dependent on AMPK‐Nampt pathway. Collectively, our data provide new insights into understanding of the molecular mechanisms of tanshinone II A inhibited Tat‐regulated transcription, suggesting that targeting AMPK/Nampt/SIRT1 pathway could serve as new anti‐HIV‐1 agents. J. Cell. Physiol. 229: 1193–1201, 2014. © 2014 Wiley Periodicals, Inc.
Distribution of slow‐cycling cells in epiphyseal cartilage and requirement of β‐catenin signaling for their maintenance in growth plate
Authors: Candela Maria Elena , Cantley Leslie , Yasuaha Rika , Iwamoto Masahiro , Pacifici Maurizio , Enomoto‐Iwamoto Motomi 
Published: January 2014

ABSTRACTSlow proliferation is one of the characteristics of stem cells. We examined the presence, distribution, and regulation of slow‐cycling cells in the developing and growing skeleton using a pulse‐chase method with a new nucleoside derivative, 5‐ethynyl‐2′‐deoxyuridine (EdU). C57BL/6 mice received daily intraperitoneal injections of EdU from postnatal day 4 to day 7. One day after the last EdU injection, a large population of cells in articular cartilage and growth plate was labeled. Six weeks after the last injection, the number of EdU‐labeled cells dramatically decreased, but a small number of them were dominantly present in the articular surface, and the labeling index was significantly higher in the surface than that in the rest of articular cartilage. In the growth plate, most EdU‐positive cells were found in the top layer that lies immediately below the secondary ossification center. Interestingly, postnatal conditional ablation of β‐catenin in cartilage caused a complete loss of the EdU‐labeled cells in growth plate that displayed disorganization and dysfunction. Together, our data demonstrate that slow‐cycling cells do reside in specific locations and numbers in both articular cartilage and growth plate. The β‐catenin signaling pathway appears to play a previously unsuspected role in maintenance of the slow‐cycling cells. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:661–668, 2014.
Folin–Ciocalteu spectrophotometric assay of ascorbic acid in pharmaceutical tablets and orange juice with pH adjustment and pre‐extraction of lanthanum(III)–flavonoid complexes
Authors: Olgun F Ayca Ozdemir , Ozyurt Dilek , Berker Kadriye Isil , Demirata Birsen , Apak Resat 
Published: January 2014

AbstractBACKGROUNDThis study proposes modifications to the conventional Folin–Ciocalteu (FC) spectrophotometric method for individually determining ascorbic acid (AA) in complex matrices in the presence of other phenolics and potential interferents. The conventional FC assay in the aqueous phase, which normally measures total water‐soluble phenolics and other antioxidants, has recently been modified by incorporating isobutanol (iso‐BuOH) in the solvent mixture for the simultaneous determination of lipophilic and hydrophilic antioxidants in foods.RESULTSInterference effects of other flavonoids and phenolics to individual AA assays were overcome by preliminary extraction–removal as their La(III) chelates into ethyl acetate (EtAc). The pH of the medium was adjusted to 3.0 in order to prevent conversion of AA into over‐oxidation products further beyond the dehydroascorbic acid stage, as encountered in the conventional FC assay carried out at pH 10. This pH does not permit most phenolics to ionise, rendering their oxidation difficult.CONCLUSIONBoth methods (conventional and iso‐BuOH‐modified FC at pH 3, with and without La(III)/EtAc pre‐extraction) were applied to the determination of ascorbic acid in pharmaceutical tablets and orange juice, showing good agreement with HPLC results. The proposed spectrophotometric methods with their low cost, simplicity, reliability, versatility and accuracy offer novelty to the determination of AA in complex matrices. © 2014 Society of Chemical Industry
Effect of power ultrasound pretreatment on peptidic profiles and angiotensin converting enzyme inhibition of milk protein concentrate hydrolysates
Authors: Uluko Hankie , Liu Lu , Li Hongjuan , Cui Wenming , Zhang Shuwen , Zhao Lili , Xue Haixiao , Lv Jiaping 
Published: January 2014

AbstractBACKGROUNDThe use of power ultrasound as a pretreatment to enhance the hydrolysis of milk protein concentrate (MPC) and subsequent angiotensin converting enzyme (ACE) inhibitory activity has been studied. Liquid chromatography was used to analyse peptide profiles of Neutrase‐derived MPC hydrolysates after pretreatment at 0, 1, 3, 5 and 8 min at an ultrasound power level of 800 W.RESULTSThe peptide profiles indicated an increase in number of peptides when ultrasound pretreatment was applied. There was also an increase in the degree of hydrolysis of MPC hydrolysates. The profiles indicated that new small peptides in ultrasound pretreated samples (1–5 min) which were not present in the control samples and 8 min pretreated samples, could be responsible for increased ACE inhibitory activity. These small peptides were digested in the 8 min pretreated samples.CONCLUSIONUltrasound pretreatment of MPC increases the ACE inhibitory activity of the hydrolysates because of the production of new small peptides. This can be used as a means to derive potent ACE inhibitory peptides at industrial scale in complex protein sources. © 2014 Society of Chemical Industry
The polyphenol quercetin protects themev‐1mutant ofCaenorhabditis elegansfrom glucose‐induced reduction of survival under heat‐stress depending on SIR‐2.1, DAF‐12, and proteasomal activity
Authors: Fitzenberger Elena , Deusing Dorothé J. , Marx Carolin , Boll Michael , Lüersen Kai , Wenzel Uwe 
Published: January 2014

ScopeHyperglycemia is a hallmark of diabetes mellitus but slighter increases of blood glucose levels are observed also during ageing. Using theCaenorhabditis elegans mev‐1mutant, we identified molecular mechanisms underlying the protection from glucose toxicity by the polyphenol quercetin.Methods and resultsWe fedC. elegans mev‐1mutants on a liquid medium supplemented with 10 mM glucose, which resulted in a reduced survival at 37°C. The polyphenol quercetin (1 μM) was able to prevent glucose‐induced lifespan reduction completely. RNA interference revealed that the sirtuin SIR‐2.1, the nuclear hormone receptor DAF‐12, and its putative co‐activator MDT‐15 were critical for the quercetin effects. Moreover, RNA interference for key factors of proteostasis reduced survival, which was not further affected by glucose or quercetin, suggesting that those proteins are a target for both substances. Besides unfolded protein response, proper functionality of the proteasome was shown to be crucial for the survival enhancing effects of quercetin and the polyphenol was finally demonstrated to activate proteasomal degradation.ConclusionOur studies demonstrate that lowest concentrations of quercetin prevent a glucose‐induced reduction of survival. SIR‐2.1, DAF‐12, and MDT‐15 were identified as targets that activate unfolded protein response and proteasomal degradation to limit the accumulation of functionally restricted proteins.
Increased expression of ERp57 in rat oocytes during meiotic maturation is associated with sperm–egg fusion
Authors: Liu Yue , Zhu Yemin , Wu Xiaohui , Li Yandong , Guo Qiangsu , Li Weiping , Ding Zhide 
Published: January 2014

SUMMARYOocyte meiotic maturation is a developmental transition that starts during germinal‐vesicle breakdown and ends at the arrest in metaphase of meiosis II. This transition is associated with changes to both the proteins that are synthesized and the abundance/distribution of post‐translational modifications that are crucial for subsequent fertilization and embryogenesis. Here, we isolated and cultured rat oocytes in vitro during both metaphase of meiosis I (MI) and meiosis II (MII) stages, respectively, and then compared their proteomic profiles by high‐resolution, two‐dimensional gel electrophoresis (2DE) followed by mass spectrometry. We found that the expression of five proteins was up‐regulated while six proteins were down‐regulated when comparing MI to MII oocytes. The expression of ERp57, an endoplasmic reticulum chaperone, underwent a dramatic increase between MI and MII oocytes, and became concentrated in a dome‐shaped area of the cell surface within the microvillar region. A similar profile was observed during spermatogenesis, and sperm ERp57 eventually localized to the head and flagellum surfaces, finally ending in the equatorial region of acrosome‐reacted sperm. Given the localization pattern, we tested and found that a polyclonal antiserum created against recombinant rat ERp57 significantly inhibited spermatozoa from penetrating zona pellucida‐free oocytes without affecting either sperm motility or the acrosome reaction. These results indicate that ERp57 expression on oocytes, and possibly sperm, plays an important physiological role during sperm–egg fusion. Mol. Reprod. Dev. 81: 315–325, 2014. © 2014 Wiley Periodicals, Inc.
Quantitative theory of hydrophobic effect as a driving force of protein structure
Authors: Perunov Nikolay , England Jeremy L. 
Published: January 2014

AbstractVarious studies suggest that the hydrophobic effect plays a major role in driving the folding of proteins. In the past, however, it has been challenging to translate this understanding into a predictive, quantitative theory of how the full pattern of sequence hydrophobicity in a protein shapes functionally important features of its tertiary structure. Here, we extend and apply such a phenomenological theory of the sequence‐structure relationship in globular protein domains, which had previously been applied to the study of allosteric motion. In an effort to optimize parameters for the model, we first analyze the patterns of backbone burial found in single‐domain crystal structures, and discover that classic hydrophobicity scales derived from bulk physicochemical properties of amino acids are already nearly optimal for prediction of burial using the model. Subsequently, we apply the model to studying structural fluctuations in proteins and establish a means of identifying ligand‐binding and protein–protein interaction sites using this approach.
Reducing shadow size in smooth scalable secret image sharing
Authors: Liu Yan‐Xiao , Yang Ching‐Nung , Yeh Po‐Han 
Published: January 2014

ABSTRACTA (k,n)‐scalable secret image sharing (SSIS) scheme shares a secret image into n independent shadow images. This (k,n)‐SSIS scheme can simultaneously provide the properties of threshold (k or more shadow images are required in reconstruction; but k − 1 or less shadow images reveal no information on the secret image) and the scalability (when k or more than k shadow images participate in reconstruction, more shadow images can reveal more information amount of secret image). In this paper, we deal with (k,n)‐SSIS scheme with the smooth scalability such that the information amount of revealed image is “smoothly” proportional to the number of involved shadows, the whole secret image can be reconstructed only when all the n shadow images participate in reconstruction. Comparing with the existing smooth (k,n)‐SSIS schemes, the proposed scheme has the less size of shadow image. Copyright © 2014 John Wiley & Sons, Ltd.
Primers‐4‐Yeast: a comprehensive web tool for planning primers for Saccharomyces cerevisiae
Authors: Yofe Ido , Schuldiner Maya 
Published: January 2014

AbstractThe budding yeast Saccharomyces cerevisiae is a key model organism of functional genomics, due to its ease and speed of genetic manipulations. In fact, in this yeast, the requirement for homologous sequences for recombination purposes is so small that 40 base pairs (bp) are sufficient. Hence, an enormous variety of genetic manipulations can be performed by simply planning primers with the correct homology, using a defined set of transformation plasmids. Although designing primers for yeast transformations and for the verification of their correct insertion is a common task in all yeast laboratories, primer planning is usually done manually and a tool that would enable easy, automated primer planning for the yeast research community is still lacking. Here we introduce Primers‐4‐Yeast, a web tool that allows primers to be designed in batches for S. cerevisiae gene‐targeting transformations, and for the validation of correct insertions. This novel tool enables fast, automated, accurate primer planning for large sets of genes, introduces consistency in primer planning and is therefore suggested to serve as a standard in yeast research. Primers‐4‐Yeast is available at: http://www.weizmann.ac.il/Primers‐4‐Yeast Copyright © 2013 John Wiley & Sons, Ltd.
Observations of bedforms on a dissipative macrotidal beach
Authors: Miles Jon , Thorpe Antony , Russell Paul , Masselink Gerd 
Published: January 2014

Abstract
Field measurements of wave ripples and megaripples were made with a Sand Ripple Profiler in the surf and shoaling zones of a sandy macrotidal dissipative beach at Perranporth, UK in depths 1–6 m and significant wave heights up to 2.2 m. A frequency domain partitioning approach allowed quantification of height (η), length (λ) and migration rate of ripples and megaripples. Wave ripples with heights up to 2 cm and wavelengths ∼20 cm developed in low orbital velocity conditions (u
m < 0.65 m/s) with mobility number ψ < 25. Wave ripple heights decreased with increasing orbital velocity and were flattened when mean currents were >0.1 m/s. Wave ripples were superimposed on top of megaripples (η = 10 cm, λ = 1 m) and contributed up to 35 % of the total bed roughness. Large megaripples with heights up to 30 cm and lengths 1–1.8 m developed when the orbital velocity was 0.5–0.8 m/s, corresponding to mobility numbers 25–50. Megaripple heights and wavelengths increased with orbital velocity but reduced when mean current strengths were >0.15 m/s. Wave ripple and megaripple migrations were generally onshore directed in the shoaling and surf zones. Onshore ripple migration rates increased with onshore-directed (+ve) incident wave skewness. The onshore migration rate reduced as offshore-directed mean flows (undertow) increased in strength and reached zero when the offshore-directed mean flow was >0.15 m/s. The migration pattern was therefore linked to cross-shore position relative to the surf zone, controlled by competition between onshore-directed velocity skewness and offshore-directed mean flow.
Biological heterogeneity in ADNI amnestic mild cognitive impairment
Authors: Nettiksimmons Jasmine , DeCarli Charles , Landau Susan , Beckett Laurel ,   Alzheimer's Disease Neuroimaging Initiative
Published: January 2014

AbstractBackgroundPrevious work examining normal controls from the Alzheimer's Disease Neuroimaging Initiative (ADNI) identified substantial biological heterogeneity. We hypothesized that ADNI mild cognitive impairment (MCI) subjects would also exhibit heterogeneity with possible clinical implications.MethodsADNI subjects diagnosed with amnestic MCI (n = 138) were clustered based on baseline magnetic resonance imaging, cerebrospinal fluid, and serum biomarkers. The clusters were compared with respect to longitudinal atrophy, cognitive trajectory, and time to conversion.ResultsFour clusters emerged with distinct biomarker patterns: The first cluster was biologically similar to normal controls and rarely converted to Alzheimer's disease (AD) during follow‐up. The second cluster had characteristics of early Alzheimer's pathology. The third cluster showed the most severe atrophy but barely abnormal tau levels and a substantial proportion converted to clinical AD. The fourth cluster appeared to be pre‐AD and nearly all converted to AD.ConclusionsSubjects with MCI who were clinically similar showed substantial heterogeneity in biomarkers.