bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of S‐adenosylmethionine and related sulfur metabolites in bacterial isolates of Pseudomonas aeruginosa (BAA‐47) by liquid chromatography/electrospray ionization coupled to a hybrid linear quadrupole ion trap and Fourier transform ion cyclotron resonance mass spectrometry
Authors: Cataldi Tommaso R. I. , Bianco Giuliana , Abate Salvatore , Mattia Daniela 
Published: October 2009

AbstractA comprehensive and highly selective method for detecting in bacterial supernatants a modified sulfur nucleoside, S‐adenosyl‐L‐methionine (SAM), and its metabolites, i.e., S‐adenosylhomocysteine (SAH), adenosine (Ado), 5′‐deoxy‐5′‐methylthioadenosine (MTA), adenine (Ade), S‐adenosyl‐methioninamine (dcSAM), homocysteine (Hcy) and methionine (Met), was developed. The method is based on reversed‐phase liquid chromatography with positive electrospray ionization (ESI+) coupled to a hybrid linear quadrupole ion trap (LTQ) and 7‐T Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS). A gradient elution was employed with a binary solvent of 0.05 M ammonium formate at pH 4 and acetonitrile. The assay involves a simultaneous cleanup of cell‐free bacterial broths by solid‐phase extraction and trace enrichment of metabolites with a 50‐fold concentration factor by using immobilized phenylboronic and anion‐exchange cartridges. While the quantitative determination of SAM was performed using stable‐isotope‐labeled SAM‐d3 as an internal standard, in the case of Met and Ade, Met‐13C and Ade‐15N2 were employed as isotope‐labeled internal standards, respectively. This method enabled the identification of SAM and its metabolites in cell‐free culture of Pseudomonas aeruginosa grown in Davis minimal broth (formulation without sulphur organic compounds), with routine sub‐ppm mass accuracies (−0.27 ± 0.68 ppm). The resulting contents of SCSS‐SAM, SS‐dcSAM, MTA, Ado and Met in the free‐cell supernatant of P. aeruginosa was 56.4 ± 2.1 nM, 32.2 ± 2.2 nM, 0.91 ± 0.10 nM, 19.6 ± 1.2 nM and 1.93 ± 0.02 µM (mean ± SD, n = 4 extractions), respectively. We report also the baseline separation (Rs ≥1.5) of both diastereoisomeric forms of SAM (SCSS and SCRS) and dcSAM (SS and RS), which can be very useful to establish the relationship between the biologically active versus the inactive species, SCSS/SCRS and SS/RS of SAM and dcSAM, respectively. An additional confirmation of SAM‐related metabolites was accomplished by a systematic study of their MS/MS spectra. Copyright © 2009 John Wiley & Sons, Ltd.
Zur Entwicklung und zum Einsatz des Liquid‐V‐Dampers zur Tilgung von vertikalen Brückenschwingungen – Teil 1 – Mechanische Grundlagen und Wirkungsweise
Authors: Fink Josef , Kuss Stefan 
Published: October 2009

AbstractDie Kenntnis über das dynamische Verhalten von Bauwerken gewinnt immer mehr an Bedeutung. Dies trifft insbesondere auf Brücken zu, die durch den Einsatz von hochfesten Materialien sowie komplexen Computerprogrammen schlanker und leichter denn je geplant und gebaut werden können. Dadurch wird die Berücksichtigung dynamischer Kriterien in der Planung und Bauwerksüberwachung unumgänglich. Eine Möglichkeit der Minimierung der auftretenden Schwingungen ist die Anordnung von Schwingungsdämpfern am Tragwerk, die bis dato hauptsächlich in der Form des Masse‐Feder‐Dämpfers realisiert wurden.In diesem zweiteiligen Beitrag soll der alternative Einsatz von Flüssigkeitsschwingungstilgern in V‐Form (Liquid‐V‐Damper) gegen vertikale Brückenschwingungen speziell für den Einsatz bei Fachwerkbrücken dargestellt werden. Dabei wird der Schwerpunkt im vorliegenden ersten Teil des Beitrages auf die mechanische Wirkungsweise gelegt, der zweite Teil beschäftigt sich mit den zugehörigen Versuchen sowie der praktischen Anwendung der Tilger. Auf die baupraktische Einsatzmöglichkeit der Liquid‐V‐Damper wird dabei ein besonderes Augenmerk gelegt.Development and use of the Liquid‐V‐Damper against vertical bridge vibrations. Part 1 – Mechanical basics and mode of operation.Nowadays the acknowledgment of the dynamical behavior of structures, in special for bridges, becomes more and more important because of the use of high strength materials and complex computer simulations. Due to that reasons these structures can be planed and build more slender and light weighted than ever. So the consideration of dynamical effects in the planning phase and the structure monitoring is indispensable. One possible method to reduce structural vibrations is the arrangement of dampers on the structure. The common type of dampers is the mass‐spring damper.In this two‐part paper the alternative use of tuned liquid column damper (Liquid‐V‐Damper) against vertical bridge vibrations in special designed for truss bridges is presented. The presented first part concerns with the mechanical mode of operation, the second part will present the corresponding testing series and the practical tuning of the damper. Special attention is paid to the practical use of the Liquid‐V‐Damper.
Hsp20-Engineered Mesenchymal Stem Cells Are Resistant to Oxidative Stress via Enhanced Activation of Akt and Increased Secretion of Growth Factors
Authors: Wang Xiaohong , Zhao Tiemin , Huang Wei , Wang Tao , Qian Jiang , Xu Meifeng , Kranias Evangelia G. , Wang Yigang , Fan Guo-Chang 
Published: October 2009

Abstract
Although heat-shock preconditioning has been shown to promote cell survival under oxidative stress, the nature of heat-shock response from different cells is variable and complex. Therefore, it remains unclear whether mesenchymal stem cells (MSCs) modified with a single heat-shock protein (Hsp) gene are effective in the repair of a damaged heart. In this study, we genetically engineered rat MSCs with Hsp20 gene (Hsp20-MSCs) and examined cell survival, revascularization, and functional improvement in rat left anterior descending ligation (LAD) model via intracardial injection. We observed that overexpression of Hsp20 protected MSCs against cell death triggered by oxidative stress in vitro. The survival of Hsp20-MSCs was increased by approximately twofold by day 4 after transplantation into the infarcted heart, compared with that of vector-MSCs. Furthermore, Hsp20-MSCs improved cardiac function of infarcted myocardium as compared with vector-MSCs, accompanied by reduction of fibrosis and increase in the vascular density. The mechanisms contributing to the beneficial effects of Hsp20 were associated with enhanced Akt activation and increased secretion of growth factors (VEGF, FGF-2, and IGF-1). The paracrine action of Hsp20-MSCs was further validated in vitro by cocultured adult rat cardiomyocytes with a stress-conditioned medium from Hsp20-MSCs. Taken together, these data support the premise that genetic modification of MSCs before transplantation could be salutary for treating myocardial infarction.
Disclosure of potential conflicts of interest is found at the end of this article.
Klf4 Interacts Directly with Oct4 and Sox2 to Promote Reprogramming
Authors: Wei Zong , Yang Yang , Zhang Peilin , Andrianakos Rosemary , Hasegawa Kouichi , Lyu Jungmook , Chen Xi , Bai Gang , Liu Chunming , Pera Martin , Lu Wange 
Published: October 2009

Abstract
Somatic cells can be reprogrammed to induced pluripotent stem (iPS) cells by ectopic expression of specific sets of transcription factors. Oct4, Sox2, and Klf4, factors that share many target genes in embryonic stem (ES) cells, are critical components in various reprogramming protocols. Nevertheless, it remains unclear whether these factors function together or separately in reprogramming. Here we show that Klf4 interacts directly with Oct4 and Sox2 when expressed at levels sufficient to induce iPS cells. Endogenous Klf4 also interacts with Oct4 and Sox2 in iPS cells and in mouse ES cells. The Klf4 C terminus, which contains three tandem zinc fingers, is critical for this interaction and is required for activation of the target gene Nanog. In addition, Klf4 and Oct4 co-occupy the Nanog promoter. A dominant negative mutant of Klf4 can compete with wild-type Klf4 to form defective Oct4/Sox2/Klf4 complexes and strongly inhibit reprogramming. In the absence of Klf4 overexpression, interaction of endogenous Klf4 with Oct4/Sox2 is also required for reprogramming. This study supports the idea that direct interactions between Klf4, Oct4, and Sox2 are critical for somatic cell reprogramming.
Disclosure of potential conflicts of interest is found at the end of this article.
Self-Renewal of the Long-Term Reconstituting Subset of Hematopoietic Stem Cells Is Regulated by Ikaros
Authors: Papathanasiou Peter , Attema Joanne L. , Karsunky Holger , Hosen Naoki , Sontani Yovina , Hoyne Gerard F. , Tunningley Robert , Smale Stephen T. , Weissman Irving L. 
Published: October 2009

AbstractHematopoietic stem cells (HSCs) are rare, ancestral cells that underlie the development, homeostasis, aging, and regeneration of the blood. Here we show that the chromatin-associated protein Ikaros is a crucial self-renewal regulator of the long-term (LT) reconstituting subset of HSCs. Ikaros, and associated family member proteins, are highly expressed in self-renewing populations of stem cells. Ikaros point mutant mice initially develop LT-HSCs with the surface phenotype cKit+Thy1.1(lo)Lin(-/lo)Sca1+Flk2-CD150+ during fetal ontogeny but are unable to maintain this pool, rapidly losing it within two days of embryonic development. A synchronous loss of megakaryocyte/erythrocyte progenitors results, along with a fatal, fetal anemia. At this time, mutation of Ikaros exerts a differentiation defect upon common lymphoid progenitors that cannot be rescued with an ectopic Notch signal in vitro, with hematopoietic cells preferentially committing to the NK lineage. Althoughdispensable for the initial embryonic development of blood, Ikaros is clearly needed for maintenance of this tissue. Achieving successful clinical tissue regeneration necessitates understanding degeneration, and these data provide a striking example by a discrete genetic lesion in the cells underpinning tissue integrity during a pivotal timeframe of organogenesis.Disclosure of potential conflicts of interest is found at the end of this article.
MiR-21 Regulates Adipogenic Differentiation through the Modulation of TGF-β Signaling in Mesenchymal Stem Cells Derived from Human Adipose Tissue
Authors: Kim Yeon Jeong , Hwang Soo Jin , Bae Yong Chan , Jung Jin Sup 
Published: October 2009

Abstract
A better understanding of the molecular mechanisms that govern human adipose tissue-derived mesenchymal stem cells (hASCs) differentiation could improve hASCs-based cell therapy and provide new insights into a number of diseases, including obesity. In this study, we examined the roles of microRNA-21 (miR-21) in adipogenic differentiation of hASCs. We found that miR-21 expression was transiently increased after induction of adipogenic differentiation, peaked at 3 days, and returned to the baseline level 8 days. Lentiviral overexpression of miR-21 enhanced adipogenic differentiation. Overexpression of miR-21 decreased both protein and mRNA levels of TGFBR2. The expression of TGFBR2 was decreased during adipogenic differentiation of hASCs in concordance with an increase in the level of miR-21. In contrast, inhibiting miR-21 with 2′-O-methyl-antisense microRNA increased TGFBR2 protein levels in hASCs, accompanied by decreased adipogenic differentiation. The activity of a luciferase construct containing the miR-21 target site from the TGFBR2 3′UTR was lower in LV-miR21-infected hASCs than in LV-miLacZ infected cells. TGF-β-induced inhibition of adipogenic differentiation was significantly decreased in miR-21 overexpressing cells compared with control lentivirus-transduced cells. RNA interference-mediated downregulation of SMAD3, but not of SMAD2, increased adipogenic differentiation. Overexpression and inhibition of miR-21 altered SMAD3 phosphorylation without affecting total levels of SMAD3 protein. Our data are the first to demonstrate that the role of miR-21 in the adipogenic differentiation of hASCs is mediated through the modulation of TGF-β signaling. This study improves our knowledge of the molecular mechanisms governing hASCs differentiation, which may underlie the development of obesity or other metabolic diseases.
Disclosure of potential conflicts of interest is found at the end of this article.
Joint consideration of energy‐efficiency and coverage‐preservation in microsensor networks
Authors: Amini Navid , Vahdatpour Alireza , Dabiri Foad , Noshadi Hyduke , Sarrafzadeh Majid 
Published: October 2009

AbstractThis paper presents an energy‐efficient and coverage‐preserving communication protocol which distributes a uniform energy load to the sensors in a wireless microsensor network. This protocol, called Distance‐based Segmentation (DBS), is a cluster‐based protocol that divides the entire network into equal‐area segments and applies different clustering policies to each segment to (1) reduce total energy dissipation and (2) balance the energy load among the sensors. Therefore, it prolongs the lifetime of the network and improves the sensing coverage. Moreover, the proposed routing protocol does not need any centralized support from a certain node which is at odds with aiming to establish a scalable communication protocol. Results from extensive simulations on two different network configurations show that by lowering the number of wasteful transmissions in the network, the DBS can achieve as much as a 20% reduction in total dissipated energy as compared with current cluster‐based protocols. In addition, this protocol is able to distribute energy load more evenly among the sensors in the network. Hence, it yields up to a 66% increase in the useful network lifetime. According to the simulation results, the sensing coverage degradation of the DBS is considerably slower than that of the other cluster‐based protocols. Copyright © 2009 John Wiley & Sons, Ltd.
Measuring the performance of movement‐assisted certificate revocation list distribution in VANET
Authors: Chen Jiming , Cao Xianghui , Zhang Yu , Xu Weiqiang , Sun Youxian 
Published: October 2009

AbstractVehicular Ad hoc Network (VANET) emerges as a promising technology and has chances of very likely to be deployed in the coming years. The security of vehicular networks will be an important way to facilitate road safety. In this paper, we are concerned with the problem of effective and efficient distribution of the certificate revocation units (RSUs) in vehicular networks. We propose a novel distributed approach by introducing mobile nodes that have public safety. An optimal route for mobile nodes is designed to cover blind areas under both delay and cost constraints. The performances of the movement‐assisted approach are measured and evaluated by extensive experiments in large scale networks for Certificate Revocation List (CRL) distribution in VANET. The results show that the proposed movement‐assisted approach obviously improves the performance. Copyright © 2009 John Wiley & Sons, Ltd.
A survey and challenges in routing and data dissemination in vehicular ad hoc networks
Authors: Chen Wai , Guha Ratul K. , Kwon Taek Jin , Lee John , Hsu Yuan‐Ying 
Published: October 2009

AbstractIn this paper, we survey recent results in vehicular ad hoc networks (VANETs) data dissemination. We describe methods proposed to enforce dissemination scope such as geocast/broadcast and multicast. A growing category consisting of methods designed to achieve disruption tolerance in vehicular networks is presented. We describe the key ideas of representative technologies in each category. In addition, we consider location service and security issues that are crucial for data dissemination in VANET. We conclude by sharing our thoughts on further challenges. Copyright © 2009 John Wiley & Sons, Ltd.
Performance of vehicular delay‐tolerant networks with relay nodes
Authors: Farahmand Farid , Cerutti Isabella , Patel Ankitkumar N. , Jue Jason P. , Rodrigues Joel J. P. C. 
Published: October 2009

AbstractDelay‐tolerant networking (DTN) is an architecture to enable data communications between isolated or remote regions, where long delays and intermittent connectivity can be tolerated. An emerging class of DTN, called Vehicular DTNs (VDTN), exploits transportation systems as the transport layer to transfer data. In these networks, vehicles (e.g., buses, boats, and trains) act as mobile nodes and carry data messages around. Mobile nodes can exchange data messages using devices called relay nodes. Relay nodes, placed in strategic positions along vehicle routes, have the capability to download, store, and upload the data messages from/to the mobile nodes. An important issue in VDTN is the optimal placement of the relay nodes such that delay‐tolerant connectivity in VDTN is ensured at minimum cost. In this paper we show that the problem of optimal relay node placement is an NP‐hard problem. Other contributions of this paper are the formulation of the relay node placement problem using integer linear programming (ILP) formulation and the proposal of heuristic algorithms solving the optimization problem. Using simulation results, we compare the performance of each algorithm under different network constraints, such as node storage capability and network topology. Copyright © 2009 John Wiley & Sons, Ltd.
Analysis of nutrient concentrations in the diet, serum, and urine of giraffe from surveyed North American zoological institutions
Authors: Sullivan Kathleen , van Heugten Eric , Ange‐van Heugten Kimberly , Poore Matthew H. , Dierenfeld Ellen S. , Wolfe Barbara 
Published: October 2009

AbstractThe objectives of the present research were to conduct a survey to investigate the health history and feeding practices of giraffe in captivity in North America and to obtain samples of hay, concentrate, browse, urine, and serum to compare across zoos, possible factors relating to the development of urolithiasis. Forty‐one out of 98 institutions contacted responded, representing 218 giraffe. All responding zoos fed concentrate and alfalfa hay was the primary forage. Sixty‐five percent of zoos fed browse and 43 different species of browse were listed. Six zoos reported a history of urolithiasis, seven reported wasting syndrome, and 10 reported sudden death. The median daily amount (as fed) of concentrate and hay offered were 5.45 kg (range of 2.73–9.55 kg) and 6.82 kg (range of 2.53–12.50 kg), respectively. The concentrate:hay ratio of the offered diet ranged from 0.22 to 3.47 with a median value of 0.79. Forty‐three percent of the institutions offered a ratio greater than 1:1. Samples of concentrate and hay (six zoos), serum (five zoos), and urine (seven zoos) were obtained for chemical analyses. Analyzed nutrient content of the consumed diet, measured by weighing feed and orts for three consecutive days, met recommendations for giraffe, but was excessive for crude protein and P. Concentrate:hay and serum P were positively correlated (r=0.72; P<0.05). High dietary P content and a high level of concentrate relative to hay may be contributing factors to urolith formation and warrant further investigation. Zoo Biol 29:457–469, 2010. © 2009 Wiley‐Liss, Inc.
Contrafreeloading in grizzly bears: implications for captive foraging enrichment
Authors: McGowan Ragen T. S. , Robbins Charles T. , Alldredge J. Richard , Newberry Ruth C. 
Published: October 2009

AbstractAlthough traditional feeding regimens for captive animals were focused on meeting physiological needs to assure good health, more recently emphasis has also been placed on non‐nutritive aspects of feeding. The provision of foraging materials to diversify feeding behavior is a common practice in zoos but selective consumption of foraging enrichment items over more balanced “chow” diets could lead to nutrient imbalance. One alternative is to provide balanced diets in a contrafreeloading paradigm. Contrafreeloading occurs when animals choose resources that require effort to exploit when identical resources are freely available. To investigate contrafreeloading and its potential as a theoretical foundation for foraging enrichment, we conducted two experiments with captive grizzly bears (Ursus arctos horribilis). In Experiment 1, bears were presented with five foraging choices simultaneously: apples, apples in ice, salmon, salmon in ice, and plain ice under two levels of food restriction. Two measures of contrafreeloading were considered: weight of earned food consumed and time spent working for earned food. More free than earned food was eaten, with only two bears consuming food extracted from ice, but all bears spent more time manipulating ice containing salmon or apples than plain ice regardless of level of food restriction. In Experiment 2, food‐restricted bears were presented with three foraging choices simultaneously: apples, apples inside a box, and an empty box. Although they ate more free than earned food, five bears consumed food from boxes and all spent more time manipulating boxes containing apples than empty boxes. Our findings support the provision of contrafreeloading opportunities as a foraging enrichment strategy for captive wildlife. Zoo Biol 29:484–502, 2010. © 2009 Wiley‐Liss, Inc.
GAPs in the study of zoo and wild animal welfare
Authors: Goulart Vinícius D. , Azevedo Pedro G. , van de Schepop Joanna A. , Teixeira Camila P. , Barçante Luciana , Azevedo Cristiano S. , Young Robert J. 
Published: October 2009

AbstractTo investigate the science of animal welfare for zoo and wild animals in the period from 1966 to 2007, we conducted a bibliometric analysis of abstracts downloaded from The Web of Science© database using the keyword combination “Animal welfare, Zoo* and wild” in the topic field. In total we downloaded 1,125 abstracts, which were classified into the following categories: year of publication; environment of the study (e.g., zoo) or theoretical; area of knowledge (e.g., conservation in situ); number of experimental animals used; species; addresses of authors; taxonomic classification; publication language; journal name; number of citations received. Since 1990, there has been a rapid increase in the number of articles published in this area of animal welfare. One worrying result was that published articles were predominately of a theoretical nature (58.65%, N=563). Most of the articles were published by authors either in Europe (47.43%, N=480) or North America (37.65%, N=381) and written in English (87.71%, N=971). The majority of experimental studies were conducted with mammals (75.92%, N=391), and had small sample sizes (N=7 for zoo‐based studies). In terms of impact factor (IF), the journals in this study had a median factor equivalent to that for the area of biological sciences (median IF=1.013). Little knowledge cross‐over from farm animal welfare was found (only four articles) in this study. In conclusion, zoo and wild animal welfare as a science may benefit from a greater interaction with farm animal welfare. Zoo Biol 28:561–573, 2009. © 2009 Wiley‐Liss, Inc.
High Methanol Oxidation Activity of Well-Dispersed Pt Nanoparticles on Carbon Nanotubes Using Nitrogen Doping
Authors: Fang Wei-Chuan 
Published: October 2009

Abstract
Pt nanoparticles (NPs) with the average size of 3.14 nm well dispersed on N-doped carbon nanotubes (CNTs) without any pretreatment have been demonstrated. Structural properties show the characteristic N bonding within CNTs, which provide the good support for uniform distribution of Pt NPs. In electrochemical characteristics, N-doped CNTs covered with Pt NPs show superior current density due to the fact that the so-called N incorporation could give rise to the formation of preferential sites within CNTs accompanied by the low interfacial energy for immobilizing Pt NPs. Therefore, the substantially enhanced methanol oxidation activity performed by N-incorporation technique is highly promising in energy-generation applications.