bluuebunny/crossref_metadata_2025_split huggingface dataset:
Is a genetic defect in Fkbp6 a common cause of azoospermia in humans?
Authors: Miyamato Toshinobu , Sato Hisashi , Yogev Leah , Kleiman Sandra , Namiki Mikio , Koh Eitetsu , Sakugawa Naoko , Hayashi Hiroaki , Ishikawa Mutsuo , Lamb Dolores , Sengoku Kazuo 
Published: September 2006

AbstractFK506-binding protein 6 (Fkbp6) is a member of a gene family containing a prolyl isomerase/FK506-binding domain and tetratricopeptide protein-protein interaction domains. Recently, the targeted inactivation of Fkbp6 in mice has been observed to result in aspermic males and the absence of normal pachytene spermatocytes. The loss of Fkbp6 results in abnormal pairing and a misalignment of the homologous chromosomes, and in non-homologous partner switches and autosynapsis of the X chromosome cores in meiotic spermatocytes. In this study, we analyzed whether human FKBP6 gene defects might be associated with human azoospermia. We performed a mutation analysis in all the coding regions of the human FKBP6 gene in 19 patients with azoospermia resulting from meiotic arrest. The expression of the human FKBP6 gene was specific to the testis, and a novel polymorphism site, 245C → G (Y60X) could be found in exon 3. Our findings suggest that the human FKBP6 gene might be imprinted in the testis based on an analysis using two polymorphism sites.
Plant dehydrins — Tissue location, structure and function
Authors: Rorat Tadeusz 
Published: September 2006

AbstractDehydrins (DHNs) are part of a large group of highly hydrophilic proteins known as LEA (Late Embryogenesis Abundant). They were originally identified as group II of the LEA proteins. The distinctive feature of all DHNs is a conserved, lysine-rich 15-amino acid domain, EKKGIMDKIKEKLPG, named the K-segment. It is usually present near the C-terminus. Other typical dehydrin features are: a track of Ser residues (the S-segment); a consensus motif, T/VDEYGNP (the Y-segment), located near the N-terminus; and less conserved regions, usually rich in polar amino acids (the Φ-segments). They do not display a well-defined secondary structure. The number and order of the Y-, S-and K-segments define different DHN sub-classes: YnSKn, YnKn, SKn, Kn and KnS. Dehydrins are distributed in a wide range of organisms including the higher plants, algae, yeast and cyanobacteria. They accumulate late in embryogenesis, and in nearly all the vegetative tissues during normal growth conditions and in response to stress leading to cellular dehydration (e.g. drought, low temperature and salinity). DHNs are localized in different cell compartments, such as the cytosol, nucleus, mitochondria, vacuole, and the vicinity of the plasma membrane; however, they are primarily localized to the cytoplasm and nucleus. The precise function of dehydrins has not been established yet, but in vitro experiments revealed that some DHNs (YSKn-type) bind to lipid vesicles that contain acidic phospholipids, and others (KnS) were shown to bind metals and have the ability to scavenge hydroxyl radicals [Asghar, R. et al. Protoplasma 177 (1994) 87–94], protect lipid membranes against peroxidation or display cryoprotective activity towards freezing-sensitive enzymes. The SKn-and K-type seem to be directly involved in cold acclimation processes. The main question arising from the in vitro findings is whether each DHN structural type could possess a specific function and tissue distribution. Much recent in vitro data clearly indicates that dehydrins belonging to different subclasses exhibit distinct functions.
Forces between Surfactant‐Coated ZnS Nanoparticles in Dodecane: Effect of Water
Authors: Godfrey Alig A. R. , Akbulut M. , Golan Y. , Israelachvili J. 
Published: September 2006

AbstractThe forces between mica surfaces confining solutions of spherical and rod‐shaped ZnS nanoparticles (diameter ca. 5 nm) coated with hexadecylamine or octadecylamine surfactant in dodecane have been measured in the absence and after the introduction of trace amounts of water. Initially, or at very low water content, the water molecules cause the nanoparticles to aggregate and adsorb on the hydrophilic mica surfaces, resulting in a long‐range exponentially decaying repulsive force between the surfaces. After longer times (> 20 h), water bridges nucleate and grow between the nanoparticles and mica surfaces, and attractive capillary forces then cause a long‐range attraction and a strong (short‐range) adhesion. It is found, as has previously been observed in nonaqueous bulk colloidal systems, that even trace amounts of water have a profound effect on the interactions and structure of nanoparticle assemblies in thin films, which in turn affect their physical properties. These effects should be considered in the design of thin‐film processing methodologies.
Efficient Polymer Electrophosphorescent Devices with Interfacial Layers
Authors: Yang X. H. , Jaiser F. , Stiller B. , Neher D. , Galbrecht F. , Scherf U. 
Published: September 2006

AbstractIt is shown that several polymers can form insoluble interfacial layers on a poly(ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) layer after annealing of the double‐layer structure. The thickness of the interlayer is dependent on the characteristics of the underlying PEDOT:PSS and the molecular weight of the polymers. It is further shown that the electronic structures of the interlayer polymers have a significant effect on the properties of red‐light‐emitting polymer‐based electrophosphorescent devices. Upon increasing the highest occupied molecular orbital and lowest unoccupied molecular orbital positions, a significant increase in current density and device efficiency is observed. This is attributed to efficient blocking of electrons in combination with direct injection of holes from the interlayer to the phosphorescent dye. Upon proper choice of the interlayer polymer, efficient red, polymer‐based electrophosphorescent devices with a peak luminance efficiency of 5.5 cd A–1 (external quantum efficiency = 6 %) and a maximum power‐conversion efficiency of 5 lm W–1 can be realized.
Theoretical Design of Catalysts for the Heterolytic Splitting of H2
Authors: Maj Ł. , Grochala W. 
Published: September 2006

AbstractHere, we briefly review recent advances in H2 storage technologies relying on mixed proton–hydride and destabilized hydride materials. We establish a general relationship across different materials: the higher the effective H content, the higher the temperatures needed to completely desorb H2. Nevertheless, several systems show promising thermodynamics for H2 desorption; however, the desorption kinetics still needs to be improved by the use of appropriate catalysts. Prompted by the importance of heterolytically splitting stable dihydrogen molecules for proton–hydride technologies, we attempt to theoretically design novel H2 transfer catalysts. We focus mainly on M4Nm4H8 catalysts (M = V, Ti, Zr, Hf, and Nm = Si, C, B, N), which should be able to preserve their functionality in the strongly reducing environment of a H2 storage system. We are able to determine the energy of H2 detachment from these molecules, as well as the associated energy barriers. In order to optimize the properties of the catalysts, we use isoelectronic atom‐by‐atom substitutions, vary the valence electron count, and borrow the concept of near‐surface alloys from extended solids and apply it to molecular systems. We are able to obtain control over the enthalpy and electronic barriers for H2 detachment. Molecules with the coordinatively unsaturated > TiSi < unit exhibit particularly favorable thermodynamics and show unusually small electronic barriers for H2 detachment (> 0.27 eV) and attachment (> 0.07 eV). These and homologous ZrSi frameworks may serve as novel H2 transfer catalysts for use with emerging lightweight hydrogen storage materials holding 5.0–10.4 wt % hydrogen, such as Li2NH, Li2Mg(NH)2, Mg2Si, and LiH/MgB2 (discharged forms). Catalytic properties are also anticipated for appropriate defects on the surfaces and crystal edges of solid Ti and Zr silicides, and for TiSi ad‐units chemisorbed on other support materials.
Estimating radiant fields in flat heterogeneous photoreactors by the six‐flux model
Authors: Brucato A. , Cassano A. E. , Grisafi F. , Montante G. , Rizzuti L. , Vella G. 
Published: September 2006

AbstractHeterogeneous photoreactor modeling is a task complicated by the integro‐differential nature of the Radiation Transfer Equation (RTE) when scattering phenomena are important. In the present work, a novel “Six Flux Model” (SFM) is proposed, which may be regarded as a step forward with respect to the previously proposed “Two Flux Model” (TFM). In order to validate the newly proposed model, Monte Carlo simulations of an indefinite plane‐slab photoreactor have been performed. As no simplifying assumptions are involved in this case, the information obtained may be regarded as “pseudo‐experimental,” and therefore compared with the predictions of both TFM and SFM models. Results show that the novel SFM is able to closely match the exact solution of the RTE better than the TFM, still retaining the TFM advantage of a simple closed‐form solution, that is, ease of use, clearer effect of model parameters, and so forth. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Downside financial loss of sensor networks in the presence of gross errors
Authors: NguyenThanh Duy Quang , Siemanond Kitipat , Bagajewicz M. 
Published: September 2006

AbstractTheoretical expressions for assessing the expected financial loss associated with the accuracy of the instrumentation and the associated probability in the presence of two and more gross errors have been developed in previous work. However, these expressions were given in a form of integrals without closed‐form solutions. This article presents a generalized method to calculate the expected financial loss and the associated probability when two or more gross errors are present in a system. The application of financial loss calculation in the design and retrofit of a sensor network is illustrated in a simple example. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Testing for Ordered Group Effects in Binary and Continuous Outcomes
Authors: Farrell Patrick J. , Park Chul Gyu 
Published: September 2006

AbstractA likelihood ratio test is proposed for the detection of an ordered group effect on bivariate responses where one response is binary and the other is continuous. The procedure is based on a conditional logistic model for the binary response given the continuous outcome. We also develop a likelihood ratio test for simultaneously determining the goodness of fit of the ordering assumption on both responses. Our approach is motivated by a particular toxicity study application involving laboratory animals that focused on the effect of a food color additive on the development of reticuloendothelial (RE) tumors. A brief discussion on extensions to the methodology introduced here is also given, along with a comparison of the approach with a marginal strategy where the presence of an ordered group effect is assessed independently for each of the two responses. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Condensation of nonstochiometric DNA/polycation complexes by divalent cations
Authors: Budker Vladimir , Trubetskoy Vladimir , Wolff Jon A. 
Published: September 2006

AbstractThis study found that divalent cations induced the further condensation of partially condensed DNA within nonstochiometric polycation complexes. The addition of a few mmol of a divalent cation such as calcium reduced by half the inflection point at which DNA became fully condensed by poly‐L‐lysine (PLL) and a variety of other polycations. The effect on DNA condensation was initially observed using a new method, which is based on the concentration‐dependent self‐quenching of fluorescent moieties (e.g., rhodamine) covalently linked to the DNA backbone at relatively high densities. Additional analyses, which employed ultracentrifugation, dynamic light scattering, agarose gel electrophoresis, and atomic force microscopy, confirmed the effect of divalent cations. These results provide an additional accounting of the process by which divalent cations induce greater chromatin compaction that is based on the representation of chromatin fibers as a nonstoichiometric polyelectrolyte complex. They also offer a new approach to assemble nonviral vectors for gene therapy.© 2006 Wiley Periodicals, Inc. Biopolymers 83: 646–657, 2006This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Fibrin gel improved the spatial uniformity and phenotype of human chondrocytes seeded on collagen scaffolds
Authors: Malicev Elvira , Radosavljevic Damjan , Velikonja Nevenka Kregar 
Published: September 2006

AbstractA scaffold made of equine collagen type I based material has been assessed for its use in the preparation of tissue‐engineered cartilage implants with human articular chondrocytes. Improvements of cell‐seeding efficiency and specific gene expression were studied by combining solid scaffold with fibrin glue or human blood plasma. Following 3 weeks of static culture, mRNA expression levels of collagen type I, collagen type II, aggrecan and versican were analyzed by real‐time quantitative PCR and compared to those in native cartilage and monolayer cell cultures.Constructs prepared with fibrin glue or plasma showed higher cell seeding efficiencies than those prepared without gel. Chondrocytes seeded directly onto a collagen scaffold appeared fibroblastic in shape while those encapsulated in fibrin gel were spherical. The presence of fibrin glue positively influences on mRNA levels of collagen type II and aggrecan, while blood plasma enhanced only the level of collagen type II expression. Levels of collagen type I and versican decreased in presence of fibrin glue.In orthopaedics, the combination of solid collagen fleece with fibrin gel for implant preparation is seen to be preferred over solid material or even cells in a suspension, since fibrin gel improves seeding capacity of the scaffold, supports equal distribution of cells and stimulates higher chondrogenic phenotype expression. Biotechnol. Bioeng. 2007;96: 364–370. © 2006 Wiley Periodicals, Inc.
An Approach for a Synthesis of Asparagine‐Linked Sialylglycopeptides Having Intact and Homogeneous Complex‐Type Undecadisialyloligosaccharides
Authors: Yamamoto Naoki , Takayanagi Ayumi , Yoshino Ayako , Sakakibara Tohru , Kajihara Yasuhiro 
Published: September 2006

AbstractThis paper describes synthesis of asparagine‐linked sialylglycopeptides. The typical feature of our strategy for the synthesis of a sialylglycopeptide is to employ undecadisialyloligosaccharyl Fmoc‐asparagine (Fmoc‐Asn(CHO)‐OH) 1 without protecting groups on its hydroxyl groups except for the benzyl ester of the NeuAc residues. Our synthetic methodology solved the problem of esterification toward sugar hydroxyl groups by activated amino acids during the elongation of a peptide chain. When employing high concentrations of the Fmoc‐amino acid, esterification markedly occurred, but the esterification scarcely occurred when employing low concentrations of reactants. Taking advantage of these findings, we examined the synthesis of a high molecular sialylglycopeptide, CTLA‐4 fragment (113–150) 13 having two complex‐type sialyloligosaccharides by use of native chemical ligation (NCL). As a result, we succeeded in the synthesis of a sialylglycopeptide having a cysteine residue at the N‐terminus (CTLA‐4: 129–150 fragment) 11 and a sialylglycopeptide‐thioester (CTLA‐4: 113–128 fragment) 12. Finally, the sialylglycopeptides synthesized were applied to NCL reactions. The reaction successfully afforded the desired product, CTLA‐4 (113–150) 13 containing mature and pure complex‐type sialyloligosaccharides in excellent purity.
Antibiotic prophylaxis in neutropenic patients
Authors: Leibovici Leonard , Paul Mical , Cullen Michael , Bucaneve Giampaolo , Gafter‐Gvili Anat , Fraser Abigail , Kern Winfried V. 
Published: September 2006

AbstractNew evidence shows that antibiotic prophylaxis in neutropenic patients reduces mortality, febrile episodes, and bacterial infections. For patients with acute leukemia or those who undergo bone marrow transplantation, prophylaxis with fluoroquinolones diminished the risk of death from any cause by 33% (95% confidence interval [95% CI], 2–54%). Thus, 55 patients who have acute leukemia or who undergo bone marrow transplantation must receive prophylaxis to prevent 1 death. In 4 studies that included patients with solid tumors or lymphoma, prophylaxis reduced the rate of death during the first month (relative risk, 0.51; 95% CI, 0.27–0.97), and 82 patients had to receive prophylaxis to prevent 1 death. The main argument brought against prophylaxis is the induction of resistance. Patients who received prophylaxis did not experience more infections caused by resistant strains than patients in the control group. The recent GIMEMA study was conducted in a population with a nearly 50% resistance to fluoroquinolones in all pathogens and 20% resistance in gram‐negative isolates, thus indicating that prophylaxis should be offered in settings with similar or less resistance. Prophylaxis with fluoroquinolones was efficacious in reducing infections caused by gram‐positive bacteria. Patients who are treated for acute leukemia should be offered prophylaxis with ciprofloxacin or levofloxacin. Prophylaxis to cover the expected period of neutropenia may be considered for the first cycle of treatment in patients with solid tumors or lymphoma who regularly receive regimens that cause severe neutropenia. Excessive local levels of resistance to fluoroquinolones or high local incidence of infections caused by Clostridium difficile and related to fluoroquinolones should prompt a reconsideration of this policy. Cancer 2006. © 2006 American Cancer Society.
Severe alcohol‐induced neuronal deficits in the hippocampus and neocortex of neonatal mice genetically deficient for neuronal nitric oxide synthase (nNOS)
Authors: Bonthius Daniel J. , MCkim Ross A. , Koele Lindsey , Harb Harb , Kehrberg Ana Hutton , Mahoney Jo , Karacay Bahri , Pantazis Nicholas J. 
Published: September 2006

AbstractAlcohol can severely damage the developing brain, and neuronal loss is a critical component of this injury. Thus, identification of molecular factors that ameliorate alcohol‐induced neuronal loss is of great importance. Previous in vitro work has demonstrated that nitric oxide (NO) protects neurons against alcohol toxicity. We tested the hypothesis that neonatal mice carrying a null mutation for neuronal nitric oxide synthase (nNOS), the enzyme that synthesizes NO in neurons, have an increased vulnerability to alcohol‐induced neuronal loss in the neocortex and hippocampus. Wildtype mice and nNOS−/−mice received ethanol (0.0, 2.2, 3.3, or 4.4 g/kg) daily over postnatal days (P) 4–9 and were sacrificed on P10. The number of hippocampal CA1 and CA3 pyramidal cells, dentate gyrus granule cells, and neocortical neurons were determined using stereological methods. Alcohol pharmacokinetics did not differ between wildtype and nNOS−/−strains. Alcohol induced dose‐dependent reductions in all four neuronal populations, and the losses were substantially more severe in the nNOS−/−mice than in wildtype. Furthermore, the threshold dose of alcohol to induce cell death was lower in the nNOS−/−mice than in the wildtype mice for all neuronal populations. While nNOS deficiency worsened alcohol‐induced neuronal losses, the magnitude of this exacerbation varied among brain regions and depended on alcohol dose. These results demonstrate that nNOS deficiency decreases the ability of developing neurons in vivo to survive the toxic effects of alcohol and strengthen the hypothesis that NO exerts a neuroprotective effect against alcohol toxicity in the developing brain. J. Comp. Neurol. 499:290–305, 2006. © 2006 Wiley‐Liss, Inc.
Binding and complementary expression patterns of semaphorin 3E and plexin D1 in the mature neocortices of mice and monkeys
Authors: Watakabe Akiya , Ohsawa Sonoko , Hashikawa Tsutomu , Yamamori Tetsuo 
Published: September 2006

AbstractAlthough axon guidance molecules play critical roles in neural circuit formation during development, their roles in the adult circuit are not well understood. In this study we examined the expression patterns of Semaphorin 3E (Sema3E), a member of the semaphorin family, in the mature neocortices of monkeys and mice by in situ hybridization (ISH). We found that Sema3E mRNA is highly specific to layer VI throughout the macaque monkey neocortex. We further examined the ratio of Sema3E+ cells among the layer VI excitatory neurons in areas M1, S1, TE, and V1 by fluorescence double ISH, using the vesicular glutamate transporter 1 (VGluT1) gene as a specific marker for excitatory neurons. Among these areas, 34–63% of the VGluT1+ neurons expressed Sema3E mRNA. In the mouse cortex, two significant differences were observed in the pattern of Sema3E mRNA distribution. 1) Sema3E mRNA was expressed in layer Vb, in addition to layer VI in mice. 2) A subset of GABAergic interneurons expressed Sema3E mRNA in mice. By an in vitro binding experiment, we provide evidence that Plexin D1 is the specific receptor for Sema3E. Plexin D1 mRNA was preferentially expressed in layers II–V in both monkey and mouse cortices. The detailed lamina analysis by double ISH, however, revealed that Plexin D1 mRNA is expressed in layers II–Va, but not in layer Vb in the mouse cortex. Thus, the Plexin D1 and Sema3E mRNAs exhibit conserved complementary lamina patterns in mice and monkeys, despite the species differences in the pattern of each gene. J. Comp. Neurol. 499:258–273, 2006. © 2006 Wiley‐Liss, Inc.
Ultrastructural synaptic features differ between α‐ and γ‐motoneurons innervating the tibialis anterior muscle in the rat
Authors: Ichiyama Ronaldo M. , Broman Jonas , Edgerton V. Reggie , Havton Leif A. 
Published: September 2006

AbstractWe investigated the synaptology of retrogradely labeled spinal motoneurons after injection of horseradish peroxidase into the tibialis anterior (TA) muscle of adult rat. In total, 32 TA motoneurons were investigated in the electron microscope and demonstrated a bimodal size distribution with cell diameter peaks at 40 μm and 20 μm, likely representing α‐ and γ‐motoneurons, respectively. Both α‐ and γ‐motoneurons were apposed by S‐ and F‐type synaptic boutons, whereas only α‐motoneurons demonstrated inputs by the large M‐ and C‐type boutons. The proportion of cell body membrane covered by synaptic inputs was surprisingly indistinguishable between α‐motoneurons (72.2%) and γ‐motoneurons (63.5%). The ratio between the number of F‐ and S‐type boutons in apposition with the motoneuron cell body (F/S ratio) and the ratio between the soma membrane coverage provided by F‐ and S‐type boutons were both significantly higher in α‐ than in γ‐motoneurons. When comparing our data with previous findings in other species, we conclude that rat TA α‐motoneurons are similar to cat and primate α‐motoneurons with regard to synaptic terminal morphology, frequency, and distribution. However, rat γ‐motoneurons show a markedly higher total synaptic coverage and frequency than cat γ‐motoneurons, although both species exhibit appositions made by the same synaptic types and similar ratios between inhibitory and excitatory inputs. J. Comp. Neurol. 499:306–315, 2006. © 2006 Wiley‐Liss, Inc.