bluuebunny/crossref_metadata_2025_split huggingface dataset:
Single crystal EPR study of Mn(II) doped MgRb2(SO4)2·6H2O: A case of interstitial site
Authors: Sankar B. , Natarajan B. , Mithira S. , Anandhalakshmi H. , Rao P. Sambasiva 
Published: January 2007

AbstractSingle crystal electron paramagnetic resonance studies on magnesium rubidium sulphate hexahydrate doped with Mn(II) impurity, in the form of 0.1% of manganous chloride, are carried out at room temperature. The angular variation spectra of the crystal in the three orthogonal planes show that the paramagnetic impurity Mn(II) has entered the host lattice interstitially. The spin Hamiltonian parameters calculated are: gxx = 1.974, gyy = 1.928, gzz = 1.980; Axx = 9.28, Ayy = 8.58, Azz = 9.87 mT and Dxx = ‐18.71, Dyy = ‐5.59, Dzz = 24.30 mT. The room temperature and liquid nitrogen temperature study for polycrystalline sample indicate no phase transition. The percentage covalency of Mn–O bond has been estimated to be 11. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Studies on the structural, thermal and optical behaviour of solution grown organic NLO material: 8‐hydroxyquinoline
Authors: Vijayan N. , Bhagavannarayana G. , Maurya K. K. , Pal S. , Datta S. N. , Gopalakrishnan R. , Ramasamy P. 
Published: January 2007

AbstractSingle crystal of 8‐hydroxyquinoline (8HQ) having chemical formula C9H7NO, an organic nonlinear optical (NLO) material has been successfully grown by slow evaporation solution growth technique at room temperature. The crystal system has been confirmed from the powder X‐ray diffraction (PXRD) analysis. The crystalline perfection was evaluated by high resolution X‐ray diffractometry (HRXRD). From this analysis we found that the quality of the crystal is quite good. However, a very low angle (tilt angle 14 arc sec) boundary was observed which might be due to entrapping of solvent molecules in the crystal during growth. Its optical behavior has been examined by UV‐Vis. analysis, which shows the absence of absorbance between the wavelengths ranging from 400 to 1200 nm. From the thermal analysis it was observed that the material exhibits single sharp weight loss starting at 113°C without any degradation. The laser damage threshold was measured at single shot mode and the SHG behavior has been tested using Nd:YAG laser as a source. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polymeric metal‐organic octupolar NLO materials: lithium(I) and sodium(I) 3,5‐dinitrobenzoates
Authors: Yang Guang , Weng Ng Seik 
Published: January 2007

AbstractLithium 3,5‐dinitrobenzoate (Li(dnb)) exhibits a 1D propeller chain structure of D 3 point symmetry and the chains are trigonally assembled in the crystal under the chiral space group P 3121. Sodium 3,5‐dinitrobenzoate (Na(dnb)) also crystallizes in space group P 3121 and exhibits a 3D structure. The structure of Na(dnb) could be regarded to be similar to that of Li(dnb) if the weaker Na‐O(nitro) bonds were to be ignored. These two compounds represent rare examples of octupoles arranged in an octupolar environment and show modest powder SHG effects. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
fgf1 is required for normal differentiation of erythrocytes in zebrafish primitive hematopoiesis
Authors: Songhet Pascal , Adzic Dejan , Reibe Saskia , Rohr Klaus B. 
Published: January 2007

AbstractHematopoiesis in vertebrate development involves an embryonic, primitive wave and a later, definitive wave in which embryonic blood cells are replaced with adult blood cells. We here show that zebrafish fgf1 is involved in vivo in primitive hematopoiesis. Fibroblast growth factor‐1 (FGF1) morpholino knockdown leads to abnormal accumulation of blood cells in the posterior intermediate cell mass at 32 hr postfertilization. Expression of the erythroid markers gata1 and ika, normally diminishing in differentiating erythrocytes at this stage, is maintained at abnormally high levels in primitive blood cells. The onset of erythrocyte differentiation as assessed by o‐dianisidine staining is severely delayed. Most fgf1 morphants later recover to wild‐type appearance, and primitive erythrocytes eventually differentiate. Zebrafish fgf1 is syntenic to human FGF1, which maps to a critically deleted region in human del(5q) syndrome posing an increased risk of leukemia to patients. As its knockdown in zebrafish changes expression of gata1, a gene involved in hematopoietic stem cell decisions, FGF1 should be considered to play a role in the pathogenesis of del(5q) syndrome. Developmental Dynamics 236:633–643, 2007. © 2007 Wiley‐Liss, Inc.
Activation of dendritic cells by the Gal‐lectin of Entamoeba histolytica drives Th1 responses in vitro and in vivo
Authors: Ivory Catherine P. A. , Chadee Kris 
Published: January 2007

AbstractAmebiasis is a human disease caused by the protozoan intestinal parasite Entamoeba histolytica. Vaccine development has focused on the parasite's surface galactose‐N‐acetyl‐d‐galactosamine inhibitable lectin (Gal‐lectin) as a protective antigen. The Gal‐lectin is immunogenic and has been shown to induce Th1 cytokines in vitro and in vivo. The immunological basis of the protective immune response elicited by the Gal‐lectin is unknown. In this study, we investigated the response of BALB/c bone marrow‐derived DC to E. histolytica Gal‐lectin. Incubation of immature DC with Gal‐lectin resulted in activation and maturation after 24 h. FACS analysis demonstrated an up‐regulation of DC maturation markers CD80, CD86, CD40 and MHC class II upon exposure to Gal‐lectin. The Gal‐lectin also induced DC production of IL‐12, indicating a Th1 response. Gal‐lectin‐activated DC were able to stimulate T cell proliferation in an allogeneic mixed leukocyte reaction and adoptive transfer of Gal‐lectin‐treated DC into naïve mice resulted in IFN‐γ‐producing Gal‐lectin‐sensitized T cells. The activation of DC by Gal‐lectin was mediated by MAPK and NF‐κB. These findings indicate that E. histolytica Gal‐lectin is a potent vaccine antigen capable of directly initiating DC maturation and activation characterized by Th1 cytokine production.
Formation of a Ruthenium μ‐Carbide Complex with Acetylene as the Carbon Source (Eur. J. Inorg. Chem. 3/2007)
Authors: Solari Euro , Antonijevic Sasa , Gauthier Sébastien , Scopelliti Rosario , Severin Kay 
Published: January 2007

AbstractThe cover picture shows the structure of a novel ruthenium complex with a μ‐carbide ligand. This complex was obtained in an unexpected reaction from [(p‐cymene)Ru(μ‐Cl)3RuCl(C2H4)(PCy3)] and acetylene. The solid‐state 13C NMR spectrum of a μ‐carbide complex obtained from fully 13C‐labeled acetylene shows a strong peak at δ = 430.5 ppm. This confirms that acetylene was the source of the μ‐carbide ligand and that the complex was formed by cleavage of the carbon triple bond. More details about this unusual reaction are described in the Short Communication by K. Severin et al. on p. 367 ff.
Feedbacks between erosion and sediment transport in experimental bedrock channels
Authors: Johnson Joel P. , Whipple Kelin X. 
Published: January 2007

AbstractNatural bedrock rivers flow in self‐formed channels and form diverse erosional morphologies. The parameters that collectively define channel morphology (e.g. width, slope, bed roughness, bedrock exposure, sediment size distribution) all influence river incision rates and dynamically adjust in poorly understood ways to imposed fluid and sediment fluxes. To explore the mechanics of river incision, we conducted laboratory experiments in which the complexities of natural bedrock channels were reduced to a homogenous brittle substrate (sand and cement), a single sediment size primarily transported as bedload, a single erosion mechanism (abrasion) and sediment‐starved transport conditions. We find that patterns of erosion both create and are sensitive functions of the evolving bed topography because of feedbacks between the turbulent flow field, sediment transport and bottom roughness. Abrasion only occurs where sediment impacts the bed, and so positive feedback occurs between the sediment preferentially drawn to topographic lows by gravity and the further erosion of these lows. However, the spatial focusing of erosion results in tortuous flow paths and erosional forms (inner channels, scoops, potholes), which dissipate flow energy. This energy dissipation is a negative feedback that reduces sediment transport capacity, inhibiting further incision and ultimately leading to channel morphologies adjusted to just transport the imposed sediment load. Copyright © 2007 John Wiley & Sons, Ltd.
Geoarchaeology of the Kostenki–Borshchevo sites, Don River Valley, Russia
Authors: Holliday Vance T. , Hoffecker John F. , Goldberg Paul , Macphail Richard I. , Forman Steven L. , Anikovich Mikhail , Sinitsyn Andrei 
Published: January 2007

AbstractThe Kostenki–Borshchevo localities include 26 Upper Paleolithic sites on the first and second terraces along the west bank of the Don River, near Voronezh on the central East European Plain. Geoarchaeological research from 2001 through 2004 focused on sites Kostenki 1, 12, and 14, with additional work at Kostenki 11 and 16, and Borshchevo 5. The strata are grouped into three units (bottom up): Unit 1, > 50 ka, consists of coarse alluvium (representing upper terrace 2 deposits) and colluvium, overlain by fine‐grained sediments. Unit 2 includes archaeological horizons sealed within two sets of thin lenses of silt, carbonate, chalk fragments, and organic‐rich soils (termed the Lower Humic Bed and Upper Humic Bed) dating 50–30 ka. Separating the humic beds is a volcanic ash lens identified as the Campanian Ignimbrite Y5 tephra, dated elsewhere by Ar/Ar to ca. 40 ka. The humic beds appear to result from the complex interplay of soil formation, spring deposition, slope action, and other processes. Several horizons buried in the lower part of Unit 2 contain Upper Paleolithic assemblages. The springs and seeps, which are still present in the area today, emanated from the bedrock valley wall. Their presence may account for the unusually high concentration of Upper Paleolithic sites in this part of the central East European Plain. Unit 3, < 30 ka, contains redeposited loess with a buried soil (Gmelin Soil) overlain by a primary full‐glacial loess with an associated Chernozem (Mollisol), forming the surface of the second terrace. © 2007 Wiley Periodicals, Inc.
The lower paleolithic landscape of 'Ayoun Qedim, al‐Jafr Basin, Jordan
Authors: Rech Jason A. , Quintero Leslie A. , Wilke Philip J. , Winer Emily R. 
Published: January 2007

AbstractThe 'Ayoun Qedim locality includes seven deflated Acheulian sites within and around a limestone box canyon, Juwit el Ghuweir, in the northern al‐Jafr Basin, Jordan. Survey of these sites identified dense scatters of Acheulian bifaces ( _ 1650) along with debris, cores, and reduction material from their production and maintenance. Although there is a clear Levallois component in the assemblages, reflecting a Late Acheulian occupation, strictly Middle and Upper Paleolithic sites are uncommon in this locality. Analysis of the geology and geomorphology of the northern al‐Jafr Basin indicates the area is strongly influenced by shallow subsurface groundwater flow and discharge, and Juwit el Ghuweir displays classic features of a canyon formed by groundwater seepage and sapping, except for the lack of a perennial spring within the modern canyon. The authors suggest that the extreme density of Lower Paleolithic material at 'Ayoun Qedim is associated with perennial groundwater discharge at Juwit el Ghuweir during the Middle Pleistocene and that the dearth of later Paleolithic material is attributable to the cessation of perennial spring discharge. The cause of the spring's cessation is unknown, but may have been related to local geomorphic factors, such as head migration of adjacent streams, or to more regional geomorphic factors, such as the lowering of theregional water table in the area of al‐Jafr Basin. © 2007 Wiley Periodicals, Inc.
A haplotype‐linkage analysis method for estimating recombination rates using dense SNP trio data
Authors: Zhao Lue Ping , Li Shuying Sue , Shen Fumin 
Published: January 2007

AbstractMeiotic recombination is an important evolution force in shaping human genomes and creating human diversity. Recent explorations suggest that meiotic recombination events tend to happen in certain regions of the genome, leading to the hypothesis of recombination hot spots. To identify such hot spots, we describe an empirical method for estimating the recombination rate, which reflects both historical and current meiotic events, using unphased genotypes from nuclear families, in particular, parents‐child trios. The key idea is that use of the haplotypic polymorphisms with multiple adjacent SNPs will increase the number of informative meioses and hence would improve the power of linkage analysis. Since haplotypes of individuals are not directly observed, e.g., in HapMap data, we infer the haplotypes simultaneously while estimating recombination rate. We refer this described method as haplotype‐linkage (HALIN) method. Our simulation results show that HALIN gives unbiased estimates of recombination rate. We apply HALIN to analyze the genotype data of chromosome 20 from HapMap data and compare the results to the results using two existing methods, Bayesian coalescent method described by McVean et al. [2004] science 304:581–584 and empirical method by Clarke and Cardon ([2005] Genetics). Results suggest that HALIN identified 75 hot spots on chromosome 20, and 85% of them are also identified by the method by McVean et al. ([2004] science 304:581–584), in addition to a few new hot spots. In comparison with Clarke and Cardon's result, estimated recombination rates (RRs) under these 75 hot spots are significantly greater than those outside of hot spots, which support the general consistency in discovering recombination hot spots between two methods. Genet. Epidemiol. 31:154–172, 2007. © 2007 Wiley‐Liss, Inc.
An improved algorithm for analytical gradient evaluation in resolution‐of‐the‐identity second‐order Møller‐Plesset perturbation theory: Application to alanine tetrapeptide conformational analysis
Authors: Distasio Robert A. , Steele Ryan P. , Rhee Young Min , Shao Yihan , Head‐Gordon Martin 
Published: January 2007

AbstractWe present a new algorithm for analytical gradient evaluation in resolution‐of‐the‐identity second‐order Møller‐Plesset perturbation theory (RI‐MP2) and thoroughly assess its computational performance and chemical accuracy. This algorithm addresses the potential I/O bottlenecks associated with disk‐based storage and access of the RI‐MP2 t‐amplitudes by utilizing a semi‐direct batching approach and yields computational speed‐ups of approximately 2–3 over the best conventional MP2 analytical gradient algorithms. In addition, we attempt to provide a straightforward guide to performing reliable and cost‐efficient geometry optimizations at the RI‐MP2 level of theory. By computing relative atomization energies for the G3/99 set and optimizing a test set of 136 equilibrium molecular structures, we demonstrate that satisfactory relative accuracy and significant computational savings can be obtained using Pople‐style atomic orbital basis sets with the existing auxiliary basis expansions for RI‐MP2 computations. We also show that RI‐MP2 geometry optimizations reproduce molecular equilibrium structures with no significant deviations (>0.1 pm) from the predictions of conventional MP2 theory. As a chemical application, we computed the extended‐globular conformational energy gap in alanine tetrapeptide at the extrapolated RI‐MP2/cc‐pV(TQ)Z level as 2.884, 4.414, and 4.994 kcal/mol for structures optimized using the HF, DFT (B3LYP), and RI‐MP2 methodologies and the cc‐pVTZ basis set, respectively. These marked energetic discrepancies originate from differential intramolecular hydrogen bonding present in the globular conformation optimized at these levels of theory and clearly demonstrate the importance of long‐range correlation effects in polypeptide conformational analysis. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Versican modulates gap junction intercellular communication
Authors: Sheng Wang , Dong Haiheng , Lee Daniel Y. , Lu Wei‐yang , Yang Burton B. 
Published: January 2007

AbstractVersican is a large chondroitin sulfate proteoglycan and belongs to the family of lecticans. Versican possesses two globular domains, G1 and G3 domain, separated by a CS‐attachment region. The CS‐attachment region present in the middle region is divided into two spliced domains named CSα and β. Alternative splicing of versican generates at least four versican isoforms named V0, V1, V2, and V3. We have successfully cloned the full‐length cDNA of chick versican isoforms V1 and V2 and found that versican isoform V1 induced mesenchymal‐epithelial transition in NIH3T3 cells. Mesenchymal‐epithelial transition induced by V1 in NIH3T3 cells is characterized by expression of E‐cadherin and occludin, two epithelial markers, and reduced expression of fibroblastic marker vimentin (Sheng et al., 2006, Mol Biol Cell. 17, 2009–2020). In the present studies, we found that versican V1 isoform not only induced cell transition, but also increased intercellular communication via gap junction channels composed of connexin proteins. Our results showed that V1 induces plasma membrane localization of connexin 43, resulting in increased cell communication. This was further confirmed by blocking assays. Gap junctions mediated the transfer of small cytoplasmic molecules and the diffusion of second messenger molecules between adjacent cells. The ability of versican in regulating gap junction implied a potential role of versican in coordinating functions. J. Cell. Physiol. 211: 213–219, 2007. © 2007 Wiley‐Liss, Inc.
Activation of caspase‐8 and Erk‐1/2 in domes regulates cell death induced by confluence in MDCK cells
Authors: Chang Yung‐Heng , Lin Hsi‐Hui , Wang Yang‐Kao , Chiu Wen‐Tai , Su Hsiao‐Wen , Tang Ming‐Jer 
Published: January 2007

AbstractUnder normal culture conditions, cells adhere to culture dish, spread out, proliferate, and finally cover all areas and reach confluence. During the confluent stage, cell proliferation ceases and differentiation is enhanced. Meanwhile, cell death also appears as the monolayer confluence proceeds. To delineate the mechanism of cell death induced by the confluent process, we employed Madin‐Darby canine kidney (MDCK) cells. When approaching confluence, MDCK cells exhibited increase the levels of caspase‐2 and enhanced the activity of caspase‐8. Using various caspase inhibitors to block apoptosis, we found that only z‐VAD‐fmk and z‐IETD‐fmk can inhibit confluent cell death, indicating that confluent cell death is mediated by activation of caspase‐8. Overexpression of Bcl‐2 inhibited confluent cell death, suggesting the involvement of mitochondria‐dependent pathway in confluent cell death. Interestingly, the activity of phospho‐Erk (p‐Erk) was initially decreased before confluence, but markedly increased after confluence. Immunofluorescence staining studies showed that p‐Erk was expressed exclusively on dome‐forming cells that underwent apoptosis. Treatment of confluent MDCK cells with PD98059 and UO126, the inhibitors of MEK, enhanced apoptosis as well as activity of caspase‐8. These data indicate that elevation of p‐Erk activity during confluence may serve to suppress confluent cell death. Taken together, activation of caspase‐8 contributes to and results in confluent cell death, whereas elevated p‐Erk activity serves to prevent confluent cell death by regulating activation of caspase‐8. J. Cell. Physiol. 211: 174–182, 2007. © 2007 Wiley‐Liss, Inc.
Downregulation of TLR4‐dependent ATP production is critical for estrogen‐mediated immunoprotection in Kupffer cells following trauma‐hemorrhage
Authors: Hsieh Ya‐Ching , Frink Michael , Kawasaki Takashi , Thobe Bjoern M. , Choudhry Mashkoor A. , Schwacha Martin G. , Bland Kirby I. , Chaudry Irshad H. 
Published: January 2007

AbstractToll‐like receptor 4 (TLR4) mediates mitochondrial DNA (mtDNA) damage and biogenic responses. Mitochondrial transcription factor A (Tfam) is an essential regulator for mtDNA transcription and ATP production. Increased ATP levels were associated with normalization of immune function following trauma‐hemorrhage. Moreover, administration of 17β‐estradiol following trauma‐hemorrhage upregulates cardiac Tfam and ATP levels. We therefore hypothesized that the salutary effect of 17β‐estradiol on Kupffer cell function following trauma‐hemorrhage is mediated via negative regulation of TLR4, which downregulates iNOS, upregulates Tfam and mtDNA‐encoded gene cytochrome c oxidase I (mtCOI), and consequently increases cellular ATP levels. Male C3H/HeN, C3H/HeOuJ (intact TLR4), and C3H/HeJ (TLR4 mutant) mice were subjected to trauma‐hemorrhage (mean BP 35 ± 5 mmHg ∼90 min, then resuscitation) or sham operation. At the beginning of resuscitation, mice received 17β‐estradiol (25 µg/25 g) or vehicle intravenously and were sacrificed 2 h thereafter. Kupffer cell TLR4, iNOS, IL‐6 and TNF‐α production capacities were increased, and ATP, Tfam, and mtCOI levels were decreased following trauma‐hemorrhage. Administration of 17β‐estradiol following trauma‐hemorrhage prevented the increase in Kupffer cell TLR4, iNOS, and cytokine production. This was accompanied by normalized ATP, Tfam, and mtCOI levels. Furthermore, the decreased Kupffer cell ATP and mtCOI levels were not observed in TLR4 mutant mice following trauma‐hemorrhage. Taken together, these findings suggest that downregulation of TLR4‐dependent ATP production is critical to 17β‐estradiol‐mediated immunoprotection in Kupffer cells following trauma‐hemorrhage. J. Cell. Physiol. 211: 364–370, 2007. © 2007 Wiley‐Liss, Inc.
Phylogeographic inferences from the mtDNA variation of the three‐toed skink, Chalcides chalcides (Reptilia: Scincidae)
Authors: Giovannotti Massimo , Cerioni Paola Nisi , Kalboussi Mohsen , Aprea Gennaro , Caputo Vincenzo 
Published: January 2007

AbstractGenetic diversity was analyzed in Chalcides chalcides populations from peninsular Italy, Sardinia, Sicily and Tunisia by sequencing 400 bp at the 5′ end of the mitochondrial gene encoding cytochrome b (cyt b) and by restriction fragment length polymorphism (RFLP) analysis of two mitochondrial DNA segments (ND‐1/2 and ND‐3/4). The results of the phylogenetic analysis highlighted the presence of three main clades corresponding with three of the four main geographical areas (Tunisia, Sicily and the Italian peninsula), while Sardinia proved to be closely related to Tunisian haplotypes suggesting a colonization of this island from North Africa by human agency in historical times. On the contrary, the splitting times estimated on the basis of cyt b sequence data seem to indicate a more ancient colonization of Sicily and the Italian Peninsula, as a consequence of tectonic and climatic events that affected the Mediterranean Basin during the Pleistocene. Finally, the analysis of the genetic variability of C. chalcides populations showed a remarkable genetic homogeneity in Italian populations when compared to the Tunisian ones. This condition could be explained by a rapid post‐glacial expansion from refugial populations that implied serial bottlenecking with progressive loss of haplotypes, resulting in a low genetic diversity in the populations inhabiting the more recently colonized areas. J. Exp. Zool. (Mol. Dev. Evol.) 308B:297–307, 2007. © 2007 Wiley‐Liss, Inc.