bluuebunny/crossref_metadata_2025_split huggingface dataset:
Partitioning the sources of demographic variation reveals density‐dependent nest predation in an island bird population
Authors: Sofaer Helen R. , Sillett T. Scott , Langin Kathryn M. , Morrison Scott A. , Ghalambor Cameron K. 
Published: June 2014

AbstractEcological factors often shape demography through multiple mechanisms, making it difficult to identify the sources of demographic variation. In particular, conspecific density can influence both the strength of competition and the predation rate, but density‐dependent competition has received more attention, particularly among terrestrial vertebrates and in island populations. A better understanding of how both competition and predation contribute to density‐dependent variation in fecundity can be gained by partitioning the effects of density on offspring number from its effects on reproductive failure, while also evaluating how biotic and abiotic factors jointly shape demography. We examined the effects of population density and precipitation on fecundity, nest survival, and adult survival in an insular population of orange‐crowned warblers (Oreothlypis celata) that breeds at high densities and exhibits a suite of traits suggesting strong intraspecific competition. Breeding density had a negative influence on fecundity, but it acted by increasing the probability of reproductive failure through nest predation, rather than through competition, which was predicted to reduce the number of offspring produced by successful individuals. Our results demonstrate that density‐dependent nest predation can underlie the relationship between population density and fecundity even in a high‐density, insular population where intraspecific competition should be strong.
Synthesis of Magnetic Fe3O4@C Nanoparticles Modified with –SO3H and –COOH Groups for Fast Removal of Pb2+, Hg2+, and Cd2+ Ions
Authors: Chen Zhiming , Geng Zhirong , Zhang Zhiyang , Ren Lianbing , Tao Tingxian , Yang Renchun , Guo Zuxiang 
Published: June 2014

AbstractCore–shell magnetic Fe3O4@C nanoparticles functionalized with sulfonic and carboxylic acid groups were synthesized and employed to capture heavy metal ions in aqueous media. The Fe3O4 cores possess unique magnetic properties for adsorbent separation, and the –SO3H and –COOH groups attached to the surface of the carbon shells determine the efficiency of heavy metal ion removal. Batch adsorption experiments showed that Pb2+, Hg2+, and Cd2+ ions can be completely and quickly removed by the Fe3O4@C nanoparticles. The equilibrium was established within 5 min, and the maximum adsorption capacities of the Fe3O4@C nanoparticles toward Pb2+, Hg2+, and Cd2+ ions were 90.7, 83.1, and 39.7 mg/g, respectively. The removal efficiencies were 96.3, 98.1, and 93.8 % for Pb2+, Hg2+, and Cd2+ ions, respectively. This work provides a facile and general approach to synthesize magnetic functional nanocomposites for wastewater treatment.
Synthesis of a Fully Conjugated Phthalocyanine‐Diketopyrrolopyrrole‐Phthalocyanine Triad as Low Band Gap Donor in Small Molecule Bulk Heterojunction Solar Cells
Authors: Molina Desiré , Guerrero Antonio , Garcia‐Belmonte Germà , Fernández‐Lázaro Fernando , Sastre‐Santos Ángela 
Published: June 2014

AbstractWe describe the synthesis and photovoltaic properties of a fully conjugated phthalocyanine‐diketopyrrolopyrrole‐phthalocyanine triad (ZnPc‐DPP‐ZnPc) that presents strong visible absorption from 400 to 900 nm. The synthesis of the phthalocyanine with full conjugation to diketopyrrolopyrrole provides access to a new family of low band gap materials (<1.6 eV). Organic solar cells employing bulk heterojunction ZnPc‐DPP‐ZnPc:PC70BM films using MoO3 as anodic interfacial layer (IFL) show a power conversion efficiency of 1.04 %. The power conversion efficiency decreases considerably by using PEDOT:PSS as interfacial layer as a consequence of protonation of the ZnPc.
Selective Bi‐directional Amide Bond Cleavage ofN‐Methylcysteinyl Peptide
Authors: Qiu Yibo , Hemu Xinya , Liu Ding Xiang , Tam James P. 
Published: June 2014

AbstractA selective bi‐directional peptide bond cleavage mediated byN‐methylcysteine (MeCys) in Xaa‐MeCys‐Yaa peptides (Xaa and Yaa, non‐cysteine residues) leading to thioesters and thiolactones is described. Rate and product analyses showed that an Nα‐amide bond cleavage occurred at the Xaa‐MeCys bond by an N–S acyl shift to generate an Xaa‐S‐(MeCys‐Yaa) thioester at pH 1–5, whereas under strongly acidic conditions ofH0= –5, the MeCys‐Yaa bond underwent a Cα‐amide bond cleavage via an oxazolone intermediate, which was trapped by thiocresol (TC) as an Xaa‐MeCys‐TC thioester. This thioester was then transformed into an Xaa‐MeCys‐β‐thiolactone at pH 4–5. Replacing MeCys by a Cys residue did not result in significant bi‐directional peptide bond cleavage, which suggests thatN‐methylation in a MeCys residue is important for the N–S acyl shift reaction and formation of oxazolone. The isomerization of amides and thioesters was successfully used to prepare cyclic peptides.
Place field stability requires the metabotropic glutamate receptor, mGlu5
Authors: Zhang Sijie , Manahan‐Vaughan Denise 
Published: June 2014

ABSTRACTThe metabotropic glutamate (mGlu) receptors are critically involved in enabling the persistency of forms of synaptic plasticity that are believed to underlie hippocampus‐dependent memory. These receptors and in particular, mGlu5, are also required for hippocampus‐dependent learning and memory. In the hippocampus, synaptic plasticity is one of the mechanisms by which spatial information may be represented. Another mechanism involves increased firing of place cells. Place cells increase their firing activity when an animal is in a specific spatial location. Inhibition of factors that are essential for synaptic plasticity, such as N‐methyl‐d‐aspartate receptors or protein synthesis, also impair place cell activity. This raises the question as to whether mGlu receptors, that are so important for synaptic plasticity and spatial memory, are also important for place cell encoding. We examined location‐dependent place cell firing i.e. place fields. We observed that antagonism of mGlu5, using 2‐methyl‐6‐(phenylethynyl) pyridine (MPEP) had no effect on place field profiles in a familiar environment. However, in a novel environment mGlu5‐antagonism affected long‐term place field stability, reduced place cell firing and spatial information. These data strongly suggest a role for mGlu5 in the mechanisms underlying informational content and long‐term stability of place fields, and add to evidence supporting the importance of these receptors for hippocampal function. © 2014 The Authors. Hippocampus Published by Wiley Periodicals, Inc.
Role of low‐ and high‐frequency oscillations in the human hippocampus for encoding environmental novelty during a spatial navigation task
Authors: Park Jinsick , Lee Hojong , Kim Taekyung , Park Ga Young , Lee Eun Mi , Baek Seunghee , Ku Jeonghun , Kim In Young , Kim Sun I. , Jang Dong Pyo , Kang Joong Koo 
Published: June 2014

ABSTRACTThe hippocampus plays a key role in the encoding and retrieval of information related to novel environments during spatial navigation. However, the neural basis for these processes in the human hippocampus remains unknown because it is difficult to directly measure neural signals in the human hippocampus. This study investigated hippocampal neural oscillations involved in encoding novel environments during spatial navigation in a virtual environment. Seven epileptic patients with implanted intracranial hippocampal depth electrodes performed three sessions of virtual environment navigation. Each session consisted of a navigation task and a location‐recall task. The navigation task consisted of eight blocks, and in each block, the participant navigated to the location of four different objects and was instructed to remember the location of the objects. After the eight blocks were completed, a location‐recall task was performed for each of the four objects. Intracranial electroencephalography data were monitored during the navigation tasks. Theta (5–8 Hz) and delta (1–4 Hz) oscillations were lower in the first block (novel environment) than in the eighth block (familiar environment) of the navigation task, and significantly increased from block one to block eight. By contrast, low‐gamma (31–50 Hz) oscillations were higher in the first block than in the eighth block of the navigation task, and significantly decreased from block one to block eight. Comparison of sessions with high recall performance (low error between identified and actual object location) and low recall performance revealed that high‐gamma (51–100 Hz) oscillations significantly decreased from block one to block eight only in sessions with high recall performance. These findings suggest that delta, theta, and low‐gamma oscillations were associated with encoding of environmental novelty and high‐gamma oscillations were important for the successful encoding of environmental novelty. © 2014 Wiley Periodicals, Inc.
The effects of hydropeaking on hyporheic interactions based on field experiments
Authors: Casas‐Mulet Roser , Alfredsen Knut , Hamududu Byman , Timalsina Netra Prasad 
Published: June 2014

AbstractHydropeaking power production has the potential to pose serious challenges towards hydrology, water quality and ecology in the downstream water bodies. The effects of such abrupt changes of flow in hyporheic exchange have been explored in a few cases in the literature. This paper extends previous works with a study of finer time resolution in a river of a smaller size and with different climatic characteristics, adding to the current knowledge of peaking‐hyporheic interactions. A high‐frequency logging field experiment measuring hyporheic flow and temperature was conducted on a ~30 × 20 m gravel bar frequently exposed to dry conditions because of fast and abrupt flow changes. This study demonstrates that hyporheic processes are sensitive to hydropeaking with respect to rates of change, durations and temperature. Differences BETWEEN individual events, seasons, watering and dewatering processes and positions in the river bed that can be potentially relevant to ecology were investigated. Understanding the complexity of those processes at the fine scale from the physical point of view is both important for the judgement of potential ecological impacts and for the future management of such regulated systems. Copyright © 2014 John Wiley & Sons, Ltd.
Thermoelectric Materials: A Brief Historical Survey from Metal Junctions and Inorganic Semiconductors to Organic Polymers
Authors: Taroni Prospero J. , Hoces Itziar , Stingelin Natalie , Heeney Martin , Bilotti Emiliano 
Published: June 2014

AbstractThe use of thermoelectric technology is attractive in many potential applications, such as energy scavenging from waste heat. The basic principles for harvesting electricity from a temperature gradient were first discovered around 180 years ago, but the contemporary technology utilising inorganic semiconductors was only developed since the early 1950s. The widespread use of this platform has so far been limited by a combination of relatively low efficiency in energy conversion or by issues related to the utilisation of rare, expensive and/or toxic elements that can be difficult to process. Recently much interest has been focused on the use of organic materials in thermoelectric devices, prompted by the possibility of developing large‐area, low‐cost devices. Considerable research in the last 20 years has been focused on understanding and improving organic thermoelectric properties, with remarkable progress recently published for compounds such as PEDOT and others. Here we provide an overview into thermoelectricity, from the initial discoveries made by Johann Seebeck to modern practical applications including the current trends in organic thermoelectric research.
The Mechanism of Operation of Lateral and Vertical Organic Field Effect Transistors
Authors: Ben‐Sasson Ariel J. , Greenman Michael , Roichman Yohai , Tessler Nir 
Published: June 2014

AbstractIn this contribution, we describe the working principles of organic field effect transistors. To place it in context, we start with a brief description of some aspects of semiconductor field effect transistors. We then describe the standard structure and properties of laterally aligned field effect transistors and at the end, touch upon some properties of the newly developed vertically stacked field effect transistors.
Field‐Effect Mobility, Morphology and Electroluminescence of a Semiconductor Based on a DPPQuaterfluorene Quadrupolar Linear Conjugated System
Authors: Arumugam Sasikumar , Brown Roisin E. , Orofino‐Pena Clara , Findlay Neil J. , Inigo Anto Regis , Kanibolotsky Alexander L. , Skabara Peter J. 
Published: June 2014

AbstractAn organic semiconductor, expressed as a quadrupolar linear conjugated system (DPP Linear‐c), consisting of a 1,4‐diketopyrrolo[3,4‐c]pyrrole (DPP) central unit and two quaterfluorenylphenyl arms at the 3‐ and 6‐positions of the DPP fragment, is studied in organic field‐effect transistors (OFETs). The strong propensity of DPP Linear‐c to aggregate in the solid state favours the hole mobility of the semiconductor due to the alignment of HOMOs in the aggregates. The fabrication of OFETs from this novel p‐type semiconductor is reported, using different dielectrics to evaluate their effect on the overall device performance. Despite its aggregation, DPP Linear‐c remains luminescent in the solid state. Electroluminescence of a non‐optimised OLED fabricated from this material is demonstrated.
Comparative genotoxicity of nanosilver in human liver HepG2 and colon Caco2 cells evaluated by fluorescent microscopy of cytochalasin B‐blocked micronucleus formation
Authors: Sahu Saura C. , Roy Shambhu , Zheng Jiwen , Yourick Jeffrey J. , Sprando Robert L. 
Published: June 2014

ABSTRACTAs a consequence of the increased use of silver nanoparticles in food, food contact materials, dietary supplements and cosmetics to prevent fungal and bacterial growth, there is a need for validated rapid screening methods to assess the safety of nanoparticle exposure. This study evaluated two widely usedin vitrocell culture models, human liver HepG2 cells and human colon Caco2 cells, as tools for assessing the potential genotoxicity of 20‐nm nanosilver. The average silver nanoparticle size as determined by transmission electron microscopy (TEM) was 20.4 nm. Dynamic light scattering (DLS) analysis showed no large agglomeration of the silver nanoparticles. The silver concentration in a 20‐nm nanosilver solution determined by the inductively coupled plasma–mass spectrometry (ICP‐MS) analysis was 0.962 mg ml−1. Analysis by ICP‐MS and TEM demonstrated the uptake of 20‐nm silver by both HepG2 and Caco2 cells. Genotoxicity was determined by the cytochalasin B‐blocked micronucleus assay with acridine orange staining and fluorescence microscopy. Concentration‐ and time‐dependent increases in the frequency of binucleated cells with micronuclei induced by the nanosilver was observed in the concentration range of 0.5 to 15 µg ml−1in both HepG2 and Caco2 cells compared with the control. Our results indicated that HepG2 cells were more sensitive than Caco2 cells in terms of micronuclei formation induced by nanosilver exposure. In summary, the results of this study indicate that the widely usedin vitromodels, HepG2 and Caco2 cells in culture, represent potential screening models for prediction of genotoxicity of silver nanoparticles byin vitromicronucleus assay. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.
Salinomycin Suppresses LRP6 Expression and Inhibits Both Wnt/β‐catenin and mTORC1 Signaling in Breast and Prostate Cancer Cells
Authors: Lu Wenyan , Li Yonghe 
Published: June 2014

AbstractEmerging evidence indicates that activation of Wnt/β‐catenin signaling at the cell surface results in inhibition of glycogen synthase kinase 3β (GSK3β), leading to activation of mTORC1 signaling in cancer cells. The low density lipoprotein receptor‐related protein‐6 (LRP6) is an essential Wnt co‐receptor for Wnt/β‐catenin signaling. Salinomycin is a novel small molecule inhibitor of LRP6. In the present study, we found that LRP6 overexpression induced mTORC1 signaling activation in cancer cells, and that salinomycin was not only a potent Wnt/β‐catenin signaling inhibitor, but also a strong mTORC1 signaling antagonist in breast and prostate cancer cells. Mechanistically, salinomycin activated GSK3β in cancer cells. Moreover, salinomycin was able to suppress the expression of cyclin D1 and survivin, two targets of both Wnt/β‐catenin and mTORC1 signaling, in prostate and breast cancer cells, and displayed remarkable anticancer activity. Our results present novel mechanisms underlying salinomycin‐mediated cancer cell death. J. Cell. Biochem. 115: 1799–1807, 2014. © 2014 Wiley Periodicals, Inc.
Protein Kinase A Regulates the Osteogenic Activity of Osterix
Authors: He Siyuan , Choi You Hee , Choi Joong‐Kook , Yeo Chang‐Yeol , Chun ChangJu , Lee Kwang Youl 
Published: June 2014

AbstractOsterix belongs to the SP gene family and is a core transcription factor responsible for osteoblast differentiation and bone formation. Activation of protein kinase A (PKA), a serine/threonine kinase, is essential for controlling bone formation and BMP‐induced osteoblast differentiation. However, the relationship between Osterix and PKA is still unclear. In this report, we investigated the precise role of the PKA pathway in regulating Osterix during osteoblast differentiation. We found that PKA increased the protein level of Osterix; PKA phosphorylated Osterix, increased protein stability, and enhanced the transcriptional activity of Osterix. These results suggest that Osterix is a novel target of PKA, and PKA modulates osteoblast differentiation partially through the regulation of Osterix. J. Cell. Biochem. 115: 1808–1815, 2014. © 2014 Wiley Periodicals, Inc.
High‐Resolution Molecular Validation of Self‐Renewal and Spontaneous Differentiation in Clinical‐Grade Adipose‐Tissue Derived Human Mesenchymal Stem Cells
Authors: Dudakovic Amel , Camilleri Emily , Riester Scott M. , Lewallen Eric A. , Kvasha Sergiy , Chen Xiaoyue , Radel Darcie J. , Anderson Jarett M. , Nair Asha A. , Evans Jared M. , Krych Aaron J. , Smith Jay , Deyle David R. , Stein Janet L. , Stein Gary S. , Im Hee‐Jeong , Cool Simon M. , Westendorf Jennifer J. , Kakar Sanjeev , Dietz Allan B. , van Wijnen Andre J. 
Published: June 2014

AbstractImproving the effectiveness of adipose‐tissue derived human mesenchymal stromal/stem cells (AMSCs) for skeletal therapies requires a detailed characterization of mechanisms supporting cell proliferation and multi‐potency. We investigated the molecular phenotype of AMSCs that were either actively proliferating in platelet lysate or in a basal non‐proliferative state. Flow cytometry combined with high‐throughput RNA sequencing (RNASeq) and RT‐qPCR analyses validate that AMSCs express classic mesenchymal cell surface markers (e.g., CD44, CD73/NT5E, CD90/THY1, and CD105/ENG). Expression of CD90 is selectively elevated at confluence. Self‐renewing AMSCs express a standard cell cycle program that successively mediates DNA replication, chromatin packaging, cyto‐architectural enlargement, and mitotic division. Confluent AMSCs preferentially express genes involved in extracellular matrix (ECM) formation and cellular communication. For example, cell cycle‐related biomarkers (e.g., cyclins E2 and B2, transcription factor E2F1) and histone‐related genes (e.g., H4, HINFP, NPAT) are elevated in proliferating AMSCs, while ECM genes are strongly upregulated (>10‐fold) in quiescent AMSCs. AMSCs also express pluripotency genes (e.g., POU5F1, NANOG, KLF4) and early mesenchymal markers (e.g., NES, ACTA2) consistent with their multipotent phenotype. Strikingly, AMSCs modulate expression of WNT signaling components and switch production of WNT ligands (from WNT5A/WNT5B/WNT7B to WNT2/WNT2B), while upregulating WNT‐related genes (WISP2, SFRP2, and SFRP4). Furthermore, post‐proliferative AMSCs spontaneously express fibroblastic, osteogenic, chondrogenic, and adipogenic biomarkers when maintained in confluent cultures. Our findings validate the biological properties of self‐renewing and multi‐potent AMSCs by providing high‐resolution quality control data that support their clinical versatility. J. Cell. Biochem. 115: 1816–1828, 2014. © 2014 Wiley Periodicals, Inc.
Fusarium species, chemotype characterisation and trichothecene contamination of durum and soft wheat in an area of central Italy
Authors: Covarelli Lorenzo , Beccari Giovanni , Prodi Antonio , Generotti Silvia , Etruschi Federico , Juan Cristina , Ferrer Emilia , Mañes Jordi 
Published: June 2014

AbstractBACKGROUNDFusarium head blight (FHB) of wheat is an important disease causing yield losses and mycotoxin contamination. The aim of the work was to detect and characterise trichothecene producing Fusarium species in durum and soft wheat cultivated in an area of central Italy in 2009 and 2010 and to determine trichothecene contamination by LC‐MS/MS in the grain.RESULTSF. graminearum s. str. was the most frequent species. In 2009, the occurrence of F. avenaceum and F. poae was higher than in 2010. Among F. graminearum strains, the 15‐acetyl deoxynivalenol (15‐ADON) chemotype could be found more frequently, followed by nivalenol (NIV) and 3‐ADON chemotypes, while all F. culmorum isolates belonged to the 3‐ADON chemotype. All F. poae strains were NIV chemotypes. In vitro trichothecene production confirmed molecular characterisation. Durum wheat was characterised by a higher average DON contamination with respect to soft wheat, NIV was always detected at appreciable levels while type‐A trichothecenes were mostly found in durum wheat samples in 2009 with 6% of samples exceeding the contamination level recently recommended by the European Union.CONCLUSIONClimatic conditions were confirmed to be predominant factors influencing mycotoxigenic species composition and mycotoxin contaminations. However, NIV contamination was found to occur irrespective of climatic conditions, suggesting that it may often represent an under‐estimated risk to be further investigated. © 2014 Society of Chemical Industry
Consequences of Delayed Dental Extraction in Lesch‐Nyhan Disease
Authors: Goodman Emily M. , Torres Rosa J. , Puig Juan G. , Jinnah Hyder A. 
Published: June 2014

AbstractPatients with Lesch‐Nyhan disease (LND) often engage in self‐injurious biting. This problem requires difficult management choices, sometimes including removal of the teeth. Although many health care professionals are reluctant to remove teeth in a child because of the permanent negative cosmetic consequences of the edentulous state, disfigurement of the face and tongue from self‐biting can be worse. We analyzed the records of 5LNDpatients who used mouth guards to spare the teeth. Success was variable, and dental extraction ultimately was required in 4 cases. We also reviewed previously published cases on the use of dental devices to spare teeth inLND. Various devices have been recommended, but failure rates are high, and tooth extraction often is still needed. Although dental extraction is not required in all cases, it should not be delayed when biting is severe.