bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rank‐based dynamic frequency hopping without strict coordination in IEEE 802.22 WRAN system
Authors: Kinoshita Harumasa , Tachibana Takuji , Sugimoto Kenji 
Published: April 2011

SUMMARYIn IEEE 802.22 wireless regional area networks (WRAN), it is indispensable to prevent the in‐use channel from interfering with incumbent services such as digital TV. To achieve this end, in this paper, we propose a dynamic frequency hopping based on rank accounting. In this method, a base station utilizes a ranking database where a rank of a channel which is used frequently is high. Each base station uses an idle channel whose rank is the highest based on the database, and hence this can reduce the number of channels which are used for the data transmission. Moreover, the proposed method performs interference avoidance processes. The proposed method does not require a strict coordination for base stations. We evaluate the performance of the proposed method with simulation. Numerical examples show that the failure probability of the channel switching for the proposed method is smaller than that for the conventional random method. It is also shown that the number of channels that are used for the data transmission can be reduced by using the proposed method. Finally, we investigate the performance of the proposed method in some situations. Copyright © 2011 John Wiley & Sons, Ltd.
Evaluation of ecohydrologic model parsimony at local and regional scales in a semiarid grassland ecosystem
Authors: Istanbulluoglu Erkan , Wang Tiejun , Wedin David A. 
Published: March 2011

AbstractIn this study, a zero‐dimensional land surface model based on a vertically averaged representation of soil moisture in the root‐zone is coupled with grass dynamics represented by live and dead biomass pools. Five variants of the model combined the different time steps (daily vs interstorm), representations of potential evapotranspiration (PET), and constant versus variable water use efficiency (WUE). Model results were compared with field observations of soil moisture, live and dead biomass, and leaf area index (LAI) from a long‐term experiment in the Nebraska Sand Hills (NSH), USA. Results show that the simplest model configuration using a constant WUE term, PET represented from a cosine function, and an inter‐storm model time step can capture grass dynamics nearly as well as daily model simulations with variable WUE. The model is then applied across the NSH to investigate the performance of the model across a climate gradient, and identify parameters that can be calibrated to improve regional predictions. For this purpose a senescence parameter that controls the decay of live aboveground vegetation is further calibrated at 14 different locations across NSH. Model calibrations revealed the dependence of the senescence parameter to regional variations in annual precipitation. Relating the senescence coefficient to annual precipitation using an empirical equation improved the model predictions at the regional scale, and revealed a strong climatic control on grass LAI. Finally, the model is tested against some existing empirical equations that relate annual grassland productivity to annual precipitation and evapotranspiration. Copyright © 2011 John Wiley & Sons, Ltd.
Role of NKG2D and its ligands in the anti‐infectious activity of Vγ9Vδ2 T cells against intracellular bacteria
Authors: Bessoles Stéphanie , Ni Ming , Garcia‐Jimenez Sara , Sanchez Françoise , Lafont Virginie 
Published: March 2011

AbstractHuman Vγ9Vδ2 T cells play a crucial role in early immune response to intracellular pathogens. Their number is drastically increased in the peripheral blood of patients during the acute phase of brucellosis. In vitro, Vγ9Vδ2 T cells exhibit strong cytolytic activity against Brucella‐infected cells and impair intracellular growth of Brucella suis in autologous macrophages. Vγ9Vδ2 T cells use cell contact‐dependent mechanisms such as the release of lytic granules and Fas‐mediated signals to lyse infected macrophages and decrease the development of intracellular Brucella. Although the involvement of the T‐cell receptor (TCR) in the triggering of these responses is known, other surface receptors can modulate Vγ9Vδ2 T‐cell response. In this study, we have investigated a potential role of NKG2D and its ligands in the anti‐infectious activity of human Vγ9Vδ2 T cells against B. suis. We show that the recruitment of NKG2D by its ligands is sufficient to induce cytokine production and the release of lytic granules through PI3K‐dependent pathways, but can also increase the TCR‐triggered responses of Vγ9Vδ2 T cells. We also demonstrate that the interaction between NKG2D and its main ligand expressed on Brucella‐infected macrophages, UL16‐binding protein 1 (ULBP1), is involved in the inhibition of bacterium development. Altogether, these results suggest a direct contribution of NKG2D and its ligands to the anti‐infectious activity of Vγ9Vδ2 T cells.
Spectroscopic, Electrochemical, and DFT Studies of Oxo‐Centered Triruthenium Cluster Complexes with a Bis(tridentate) Triazine Ligand
Authors: Dai Feng‐Rong , Wu Yu‐Hui , Zhang Li‐Yi , Li Bin , Shi Lin‐Xi , Chen Zhong‐Ning 
Published: April 2011

AbstractOxo‐centered triruthenium–acetate complexes with a tridentate or bis(tridentate) triazine ligand have been prepared by the reaction of [Ru3O(OAc)6(py)2(CH3OH)]+ ([1]+) with a triazine ligand [3‐(2‐pyridyl)‐1,2,4‐triazine (pytz), 3‐(2‐pyrimidinyl)‐1,2,4‐triazine (pmtz), or 5,5′,6,6′‐tetramethyl‐3,3′‐bi‐1,2,4‐triazine (bdmt)]. The dimeric complex [{Ru3O(OAc)5(py)2}2(μ4‐pmtz)]2+ ([5]2+), an intercluster mixed‐valence complex ([Ru3III,III,II‐pmtz‐Ru3III,III,III]2+) containing an asymmetric bis(tridentate) pmtz ligands involved in both μ‐η1(N),η2(N,N) and orthometalated μ‐η1(C),η2(N,N) bonding modes, was prepared by substitution of a bridging acetate in the parent Ru3O(OAc)6 cluster core. Chemical or electrochemical reduction or oxidation of [5]2+ gave one‐electron reduced product [5a]+ or oxidized species [5b]3+, respectively. It is demonstrated that substitution of the bridging acetate by a triazine ligand has a remarkable impact on the electronic and redox characteristics of the triruthenium cluster derivatives. Electrochemical, UV/Vis/NIR spectra, and DFT computational studies demonstrated that there is a distinct cluster–cluster interaction between the two triruthenium cluster moieties across an asymmetric bridging bis(tridentate) triazine in the dimeric triruthenium cluster complex [5]2+.
Direct numerical simulation of electrokinetic translocation of a cylindrical particle through a nanopore using a Poisson–Boltzmann approach
Authors: Ai Ye , Qian Shizhi 
Published: March 2011

AbstractNanopore‐based sensing of single molecules is based on a detectable change in the ionic current arising from the electrokinetic translocation of individual nanoparticles through a nanopore. In this study, we propose a continuum‐based model to investigate the dynamic electrokinetic translocation of a cylindrical nanoparticle through a nanopore and the corresponding ionic current response. It is the first time to simultaneously solve the Poisson–Boltzmann equation for the ionic concentrations and the electric field contributed by the surface charges of the nanopore and the nanoparticle, the Laplace equation for the externally applied electric field, and the modified Stokes equations for the flow field using an arbitrary Lagrangian–Eulerian method. Current blockade due to the particle translocation is predicted when the electric double layers (EDLs) of the particle and the nanopore are not overlapped, which is in qualitative agreement with existing experimental observations. Effects due to the electric field intensity imposed, the EDL thickness, the nanopore's surface charge, the particle's initial orientation and lateral offset from the nanopore's centerline on the particle translocation including both translation and rotation, and the ionic current response are comprehensively investigated. Under a relatively low electric field imposed, the particle experiences a significant rotation and a lateral movement. However, the particle is aligned with its longest axis parallel to the local electric field very quickly due to the dielectrophoretic effect when the external electric field is relatively high.
Preinvasive colorectal lesion transcriptomes correlate with endoscopic morphology (polypoid vs. nonpolypoid)
Authors: Cattaneo Elisa , Laczko Endre , Buffoli Federico , Zorzi Fausto , Bianco Maria Antonia , Menigatti Mirco , Bartosova Zdena , Haider Ritva , Helmchen Birgit , Sabates‐Bellver Jacob , Tiwari Amit , Jiricny Josef , Marra Giancarlo 
Published: April 2011

AbstractImproved colonoscopy is revealing precancerous lesions that were frequently missed in the past, and ∼30% of those detected today have nonpolypoid morphologies ranging from slightly raised to depressed. To characterize these lesions molecularly, we assessed transcription of 23,768 genes in 42 precancerous lesions (25 slightly elevated nonpolypoid and 17 pedunculated polypoid), each with corresponding samples of normal mucosa. Nonpolypoid versus polypoid morphology explained most gene expression variance among samples; histology, size, and degree of dysplasia were also linked to specific patterns. Expression changes in polypoid lesions frequently affected cell‐cycling pathways, whereas cell‐survival dysregulation predominated in nonpolypoid lesions. The latter also displayed fewer and less dramatic expression changes than polypoid lesions. Paradigmatic of this trend was progressive loss through the normal > nonpolypoid > polypoid > cancer sequence of TMIGD1 mRNA and protein. This finding, along with TMIGD1 protein expression patterns in tissues and cell lines, suggests that TMIGD1 might be associated with intestinal‐cell differentiation. We conclude that molecular dysregulation in slightly elevated, nonpolypoid, precancerous colorectal lesions may be somewhat less severe than that observed in classic adenomatous polyps.
Developing channel and floodplain dimensions with limited data: a case study in the Amazon Basin
Authors: Beighley R. Edward , Gummadi Venkat 
Published: March 2011

ABSTRACTThis research builds on the concept of hydraulic geometry and presents a methodology for estimating bankfull discharge and the hydraulic geometry coefficients and exponents for a station using limited data; only stage‐discharge and Landsat imagery. The approach is implemented using 82 streamflow gauging locations in the Amazon Basin. Using the estimated values for the hydraulic geometry relations, bankfull discharge, discharge data above bankfull and upstream drainage area at each site, relationships for estimating channel and floodplain characteristics as a function of drainage area are developed. Specifically, this research provides relationships for estimating bankfull discharge, bankfull depth, bankfull width, and floodplain width as a function of upstream drainage area in the Amazon Basin intended for providing reasonable cross‐section estimates for large scale hydraulic routing models. The derived relationships are also combined with a high resolution drainage network to develop relationships for estimating cumulative upstream channel lengths and surface areas as a function of the specified minimum channel width ranging from 2 m to 1 km (i.e. threshold drainage areas ranging from 1 to 431,000 km2). At the finest resolution (i.e. all channels greater than 2 m or a threshold area of 1 km2), the Amazon Basin contains approximately 4.4 million kilometers of channels with a combined surface area of 59,700 km2. The intended use of these relationships is for partitioning total floodable area (channels versus lakes and floodplain lakes) obtained from remote sensing for biogeochemical applications (e.g. quantifying CO2 evasion in the Amazon Basin). Copyright © 2011 John Wiley & Sons, Ltd.
Sources and fate of chiral organochlorine pesticides in western U.S. National Park ecosystems
Authors: Genualdi Susan A , Hageman Kimberly J , Ackerman Luke K , Usenko Sascha , Massey Simonich Staci L 
Published: April 2011

Abstract
The enantiomer fractions (EFs) of alpha-hexachlorocyclohexane (α-HCH), cis-, trans-, and oxychlordane, and heptachlor epoxide were measured in 73 snow, fish, and sediment samples collected from remote lake catchments, over a wide range of latitudes, in seven western U.S. National Parks/Preserves to investigate their sources, fate, accumulation and biotransformation in these ecosystems. The present study is novel because these lakes had no inflow or outflow, and the measurement of chiral organochlorine pesticides (OCPs) EFs in snowpack from these lake catchments provided a better understanding of the OCP sources in the western United States, whereas their measurement in fish and sediment provided a better understanding of their biotic transformations within the lake catchments. Nonracemic α-HCH was measured in seasonal snowpack collected from continental U.S. National Parks, and racemic α-HCH was measured in seasonal snowpack collected from the Alaskan parks, suggesting the influence of regional sources to the continental U.S. parks and long-range sources to the Alaskan parks. The α-HCH EFs measured in trout collected from the lake catchments were similar to the α-HCH EFs measured in seasonal snowpack collected from the same lake catchments, suggesting that these fish did not biotransform α-HCH enantioselectively. Racemic cis-chlordane was measured in seasonal snowpack and sediment collected from Sequoia, indicating that it had not undergone significant enantioselective biotransformation in urban soils since its use as a termiticide in the surrounding urban areas. However, nonracemic cis-chlordane was measured in seasonal snowpack and sediments from the Rocky Mountains, suggesting that cis-chlordane does undergo enantioselective biotransformation in agricultural soils. The trout from these lakes showed preferential biotransformation of the (+)-enantiomer of cis-chlordane and the (−)-enantiomer of trans-chlordane. Environ. Toxicol. Chem. 2011; 30:1533–1538. © 2011 SETAC
Juvenile green frog (Rana clamitans) predatory ability not affected by exposure to carbaryl at different times during larval development
Authors: Davis Melanie J , Kleinhenz Peter , Boone Michelle D 
Published: April 2011

Abstract
Larval exposure to pesticides can occur at different times during development and can negatively impact amphibian fitness. We examined the effects of larval green frog (Rana clamitans) exposure to carbaryl at 2, 4, 8, or 16 weeks of development on juvenile predatory ability. We did not find evidence that predatory ability was affected by exposure to carbaryl, which suggests that carbaryl does not have latent effects on the predatory performance of green frogs in subsequent life stages. Environ. Toxicol. Chem. 2011; 30:1618–1620. © 2011 SETAC
An efficient low‐dissipative WENO filter scheme
Authors: Kang Lei , Lee Chun‐Hian 
Published: April 2011

SUMMARYThis paper presents a simple and efficient procedure developed for tracing discontinuities in flow fields. Numerical experiments are carried out to test the new sensor coupled with the associated nonlinear WENO dissipation filter developed to suppress the numerical dissipation. The tests show that, for a problem containing shocks and vortices, the implementation of the new sensor and an optimized WENO scheme can obtain a stable and highly resolved solution. The numerical experiments demonstrated that the new filter scheme performs efficiently both in parallel and serial running for one‐dimensional inviscid flow problems. Direct numerical simulation of a Mach 5 turbulent boundary layer over a flat plate was carried out to demonstrate the applicability of the scheme to the DNS practices. Copyright © 2011 John Wiley & Sons, Ltd.
Ganz schön turbulent …
Authors: Czarske Jürgen W. 
Published: March 2011

AbstractMesstechnik: Ein neuartiges Verfahren erfasst mikroskopische und makroskopische Strömungen berührunglos und hoch präzise. Der „Laser‐Doppler‐Geschwindigkeitsprofilsensor”︁ hat enormes Anwendungspotenzial für Wissenschaft und Technik.
Entscheidung mit Köpfchen
Authors: Weber Bernd 
Published: March 2011

AbstractOb im Autosalon oder vor dem Kühlregal: Überall hat der Mensch die Qual der Wahl. Was geschieht in seinem Gehirn, wenn er diese oder jene Alternative wählt? Mit bildgebenden Verfahren will die Neuroökonomie die biologischen Grundlagen des Verhaltens besser verstehen.
Gleich und gleich gesellt sich gern
Authors: Küppers Brigitte 
Published: March 2011

AbstractErst schauten sie der Natur auf die Finger, dann synthetisierten sie nach deren Vorbild Ketten von Molekülen, die alle dieselbe Länge und Struktur haben und sich sogar selbst vervielfältigen können. Nun legen Polymerchemiker damit die Grundlagen für neue interessante Werkstoffe.
Study of Methanol‐tolerant Oxygen Reduction Reaction at Pt–Bi/C Bimetallic Nanostructured Catalysts
Authors: Remona A. M. , Phani K. L. N. 
Published: April 2011

AbstractThe nanostructured platinum–bismuth catalysts supported on carbon (Pt3Bi/C, PtBi/C and PtBi3/C) were synthesised by reducing the aqueous metal ions using sodium borohydride (NaBH4) in presence of a microemulsion. The amount of metal loading on carbon support was found to be 10 wt.‐%. The catalyst materials were characterised by X‐ray diffraction (XRD), X‐ray fluorescence (XRF), transmission electron microscope (TEM) and electroanalytical techniques. The Pt3Bi/C, PtBi/C and PtBi3/C catalysts showed higher methanol tolerance, catalytic activity for oxygen reduction reaction (ORR) than Pt/C of same metal loading. The electrochemical stability of these nano‐sized catalyst materials for methanol tolerance was investigated by repetitive cycling in the potential range of –250 to 150 mVMSE. Bi presents an interesting system to have a control over the activity of the surface for MOR and ORR. All Pt–Bi/C catalysts exhibited higher mass activities for oxygen reduction (1–1.5 times) than Pt/C. It was found that PtBi/C catalyst exhibits better methanol‐tolerance than the other catalysts.
Hippocampal morphology in lithium and non‐lithium‐treated bipolar I disorder patients, non‐bipolar co‐twins, and control twins
Authors: van Erp Theo G.M. , Thompson Paul M. , Kieseppä Tuula , Bearden Carrie E. , Marino Alexandria C. , Hoftman Gil D. , Haukka Jari , Partonen Timo , Huttunen Matti , Kaprio Jaakko , Lönnqvist Jouko , Poutanen Veli‐Pekka , Toga Arthur W. , Cannon Tyrone D. 
Published: March 2011

AbstractBackground: Bipolar I disorder is a highly heritable psychiatric illness with undetermined predisposing genetic and environmental risk factors. We examined familial contributions to hippocampal morphology in bipolar disorder, using a population‐based twin cohort design. Methods: We acquired high‐resolution brain MRI scans from 18 adult patients with bipolar I disorder [BPI; mean age 45.6 ± 8.69 (SD); 10 lithium‐treated], 14 non‐bipolar co‐twins, and 32 demographically matched healthy comparison twins. We used three‐dimensional radial distance mapping techniques to visualize hippocampal shape differences between groups. Results: Lithium‐treated BPI patients had significantly larger global hippocampal volume compared to both healthy controls (9%) and non‐bipolar co‐twins (12%), and trend‐level larger volumes relative to non‐lithium‐treated BPI patients (8%). In contrast, hippocampal volumes in non‐lithium‐treated BPI patients did not differ from those of non‐bipolar co‐twins and control twins. 3D surface maps revealed thicker hippocampi in lithium‐treated BPI probands compared with control twins across the entire anterior‐to‐posterior extent of the cornu ammonis (CA1 and 2) regions, and the anterior part of the subiculum. Unexpectedly, co‐twins also showed significantly thicker hippocampi compared with control twins in regions that partially overlapped those showing effects in the lithium treated BPI probands. Conclusions: These findings suggest that regionally thickened hippocampi in bipolar I disorder may be partly due to familial factors and partly due to lithium‐induced neurotrophy, neurogenesis, or neuroprotection. Unlike schizophrenia, hippocampal alterations in co‐twins of bipolar I disorder probands are likely to manifest as subtle volume excess rather than deficit, perhaps indicating protective rather than risk effects. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.
The gene expression profile of unstimulated dendritic cells can be used as a predictor of function
Authors: Liu Wai M. , Dennis Jayne L. , Fowler Daniel W. , Dalgleish Angus G. 
Published: March 2011

AbstractDendritic cells (DCs) represent a subset of professional antigen presenting cell (APC) whose role is to elicit immune responses against harmful antigens. They have been used in DC vaccines to stimulate the immune system to kill cancer cells. However, successes in clinical trials have been limited, which may be attributed to a lack of appreciation of the quality of DCs used. In the present study, whole human genome microarrays were used to examine alterations in gene expression of monocyte‐derived DCs after stimulation with supernatants derived from tumours. Our primary aim was to investigate the possibility of a gene signature for DCs that could be used to forecast responsiveness to tumour stimuli. Results showed that DCs are divided into two groups based on their ability to increase costimulatory markers and to trigger T‐cell responses. The gene profiles of the immature DCs from these two groups were distinct, with particular divergence in genes from the interleukin (IL) 8 and thrombospondin‐1 hubs. A subpanel of genes was identified, whose signature of expression was capable of predicting DC‐stimulatory capacity. Overall, these studies have highlighted a gene‐based screen that predicts DC function, which could be used to guide DC‐vaccine trials.
A distinct DNA methylation profile associated with microsatellite and chromosomal stable sporadic colorectal cancers
Authors: Silver Andrew , Sengupta Neel , Propper David , Wilson Peter , Hagemann Thorsten , Patel Asif , Parker Alexandra , Ghosh Anil , Feakins Roger , Dorudi Sina , Suraweera Nirosha 
Published: March 2011

AbstractAberrant DNA methylation, microsatellite instability (MSI) and chromosomal instability (CIN) are well‐characterised molecular features of sporadic colorectal cancers (CRCs). In addition to CpG island methylator phenotype (CIMP) associated with MSI, an intermediate methylation subgroup is also a feature of non‐MSI cancers. A large proportion of CRCs have no evidence of either MSI or CIN, here called Microsatellite and Chromosomal Stable (MACS), and require their methylation profile to be established. The clinical and molecular features of 170 sporadic CRC patients were investigated and stratified into MSI, CIN and MACS groups. MACS were most often found in the left colon and had a significantly lower BRAF mutation frequency (p < 0.001) compared with MSI. MACS had better survival [hazard ratio (HR) = 0.244, p = 0.017] compared with CIN, but were similar to MSI. The methylation status of 1,505 CpG loci from cancer‐related genes was analysed in a subset of CRCs (n = 44 normal–tumour pairs) and compared with CIN, MSI and MACS status. Using two‐way hierarchical clustering, three subgroups were identified, which associated with CIN, MSI and MACS status. Using significance analysis of microarray, 16 CpG loci demonstrating methylation changes associated with MACS were identified. A combination of six loci identified MACS with 81% sensitivity and 93% specificity. This result now requires independent validation. Hypomethylation of a CpG locus within the sonic hedgehog (SHH) promoter correlated with increased gene expression and was associated significantly with MACS cancers. In conclusion, we propose that MACS have distinct clinicopathological features and can be distinguished from other CRCs by a specific set of methylation loci.