bluuebunny/crossref_metadata_2025_split huggingface dataset:
Connection Between the Rag4 Glucose Sensor and the KlRgt1 Repressor in Kluyveromyces lactis
Authors: Rolland Stéphane , Hnatova Martina , Lemaire Marc , Leal-Sanchez Juana , Wésolowski-Louvel Micheline 
Published: June 2006

Abstract
The RAG4 gene encodes for the sole transmembrane glucose sensor of Kluyveromyces lactis. A rag4 mutation leads to a fermentation-deficient phenotype (Rag− phenotype) and to a severe defect in the expression of the major glucose transporter gene RAG1. A recessive extragenic suppressor of the rag4 mutation has been identified. It encodes a protein (KlRgt1) 31% identical to the Saccharomyces cerevisiae Rgt1 regulator of the HXT genes (ScRgt1). The Klrgt1 null mutant displays abnormally high levels of RAG1 expression in the absence of glucose but still presents an induction of RAG1 expression in the presence of glucose. KlRgt1 is therefore only a repressor of RAG1. As described for ScRgt1, the KlRgt1 repressor function is controlled by phosphorylation in response to high glucose concentration and this phosphorylation is dependent on the sensor Rag4 and the casein kinase Rag8. However, contrary to that observed with ScRgt1, KlRgt1 is always bound to the RAG1 promoter. This article reveals that the key components of the glucose-signaling pathway are conserved between S. cerevisiae and K. lactis, but points out major differences in Rgt1 regulation and function that might reflect different carbon metabolism of these yeasts.
A Role for Sterol Levels in Oxygen Sensing in Saccharomyces cerevisiae
Authors: Davies Brandon S J , Rine Jasper 
Published: June 2006

Abstract
Upc2p and Ecm22p are a pair of transcription factors responsible for the basal and induced expression of genes encoding enzymes of ergosterol biosynthesis in yeast (ERG genes). Upc2p plays a second role as a regulator of hypoxically expressed genes. Both sterols and heme depend upon molecular oxygen for their synthesis, and thus the levels of both have the potential to act as indicators of the oxygen environment of cells. Hap1p is a heme-dependent transcription factor that both Upc2 and Ecm22p depend upon for basal level expression of ERG genes. However, induction of both ERG genes and the hypoxically expressed DAN/TIR genes by Upc2p and Ecm22p occurred in response to sterol depletion rather than to heme depletion. Indeed, upon sterol depletion, Upc2p no longer required Hap1p to activate ERG genes. Mot3p, a broadly acting repressor/activator protein, was previously shown to repress ERG gene expression, but the mechanism was unclear. We established that Mot3p bound directly to Ecm22p and repressed Ecm22p- but not Upc2p-mediated gene induction.
Nucleotide Variation and Haplotype Diversity in a 10-kb Noncoding Region in Three Continental Human Populations
Authors: Zhao Zhongming , Yu Ning , Fu Yun-Xin , Li Wen-Hsiung 
Published: June 2006

Abstract
Noncoding regions are usually less subject to natural selection than coding regions and so may be more useful for studying human evolution. The recent surveys of worldwide DNA variation in four 10-kb noncoding regions revealed many interesting but also some incongruent patterns. Here we studied another 10-kb noncoding region, which is in 6p22. Sixty-six single-nucleotide polymorphisms were found among the 122 worldwide human sequences, resulting in 46 genotypes, from which 48 haplotypes were inferred. The distribution patterns of DNA variation, genotypes, and haplotypes suggest rapid population expansion in relatively recent times. The levels of polymorphism within human populations and divergence between humans and chimpanzees at this locus were generally similar to those for the other four noncoding regions. Fu and Li's tests rejected the neutrality assumption in the total sample and in the African sample but Tajima's test did not reject neutrality. A detailed examination of the contributions of various types of mutations to the parameters used in the neutrality tests clarified the discrepancy between these test results. The age estimates suggest a relatively young history in this region. Combining three autosomal noncoding regions, we estimated the long-term effective population size of humans to be 11,000 ± 2800 using Tajima's estimator and 17,600 ± 4700 using Watterson's estimator and the age of the most recent common ancestor to be 860,000 ± 258,000 years ago.
Assessment of Linkage Disequilibrium in Potato Genome With Single Nucleotide Polymorphism Markers
Authors: Simko Ivan , Haynes Kathleen G , Jones Richard W 
Published: June 2006

Abstract
The extent of linkage disequilibrium (LD) is an important factor in designing association mapping experiments. Unlike other plant species that have been analyzed so far for the extent of LD, cultivated potato (Solanum tuberosum L.), an outcrossing species, is a highly heterozygous autotetraploid. The favored genotypes of modern cultivars are maintained by vegetative propagation through tubers. As a first step in the LD analysis, we surveyed both coding and noncoding regions of 66 DNA fragments from 47 accessions for single nucleotide polymorphism (SNP). In the process, we combined information from the potato SNP database with experimental SNP detection. The total length of all analyzed fragments was &gt;25 kb, and the number of screened sequence bases reached almost 1.4 million. Average nucleotide polymorphism (θ = 11.5 × 10−3) and diversity (π = 14.6 × 10−3) was high compared to the other plant species. The overall Tajima's D value (0.5) was not significant, but indicates a deficit of low-frequency alleles relative to expectation. To eliminate the possibility that an elevated D value occurs due to population subdivision, we assessed the population structure with probabilistic statistics. The analysis did not reveal any significant subdivision, indicating a relatively homogenous population structure. However, the analysis of individual fragments revealed the presence of subgroups in the fragment closely linked to the R1 resistance gene. Data pooled from all fragments show relatively fast decay of LD in the short range (r2 = 0.208 at 1 kb) but slow decay afterward (r2 = 0.137 at ∼70 kb). The estimate from our data indicates that LD in potato declines below 0.10 at a distance of ∼10 cM. We speculate that two conflicting factors play a vital role in shaping LD in potato: the outcrossing mating type and the very limited number of meiotic generations.
The Contributions of Protein Kinase A and Smoothened Phosphorylation to Hedgehog Signal Transduction in Drosophila melanogaster
Authors: Zhou Qianhe , Apionishev Sergey , Kalderon Daniel 
Published: June 2006

Abstract
Protein kinase A (PKA) silences the Hedgehog (Hh) pathway in Drosophila in the absence of ligand by phosphorylating the pathway's transcriptional effector, Cubitus interruptus (Ci). Smoothened (Smo) is essential for Hh signal transduction but loses activity if three specific PKA sites or adjacent PKA-primed casein kinase 1 (CK1) sites are replaced by alanine residues. Conversely, Smo becomes constitutively active if acidic residues replace those phosphorylation sites. These observations suggest an essential positive role for PKA in responding to Hh. However, direct manipulation of PKA activity has not provided strong evidence for positive effects of PKA, with the notable exception of a robust induction of Hh target genes by PKA hyperactivity in embryos. Here we show that the latter response is mediated principally by regulatory elements other than Ci binding sites and not by altered Smo phosphorylation. Also, the failure of PKA hyperactivity to induce Hh target genes strongly through Smo phosphorylation cannot be attributed to the coincident phosphorylation of PKA sites on Ci. Finally, we show that Smo containing acidic residues at PKA and CK1 sites can be stimulated further by Hh and acts through Hh pathways that both stabilize Ci-155 and use Fused kinase activity to increase the specific activity of Ci-155.
Septicemia in a young dog following treatment of patent ductus arteriosus via coil occlusion
Authors: Wood Anne C. , Fine Deborah M. , Spier Alan W. , Eyster George E. 
Published: June 2006

Abstract
Case Description—A 12-week-old female English Springer Spaniel was evaluated for lethargy, vomiting, and pyrexia 1 week after treatment of patent ductus arteriosus (PDA) via coil occlusion.
Clinical Findings—Test results were consistent with septicemia, and the assumption was made that the PDA occlusion coils were infected. Radiography revealed partial migration of the coil mass into the pulmonary artery and signs of congestive heart failure.
Treatment and Outcome—After successful treatment of the septicemia and heart failure, surgical removal of the coils and resection of the PDA were undertaken. Although the coil that embolized to the pulmonary vasculature was left in place, the dog's clinical signs resolved.
Clinical Relevance—This case highlights the fact that as PDA coil occlusion devices become more widely used in dogs, practitioners must be prepared to treat implant infections aggressively, with both medical and surgical interventions if necessary.
Metal Bioavailability: How Does its Significance Change in the Time?
Authors: Calace Nicoletta , Petronio Bianca Maria , Pietroletti Marco 
Published: June 2006

AbstractThe significance of terms “metal bioavailability” and “bioavailable metal fraction” is evolved in the time, passing from a very simple concept to a complex concept bound to abiotic and biotic aspects. At the beginning metal toxicity was related to metal fraction present in water phase, than only free metal ion activity was considered and the free ion activity model (FIAM) was proposed. Successively, due to the exceptions observed and to the consciousness that metal bioavailability could be considered as dynamic characteristic the concept of metal bioavailability became very complex, depending on physical, chemical and biological factors.
Tracer measurements in groyne fields for the quantification of mean hydraulic residence times and of the exchange with the stream
Authors: Kozerski Hans‐Peter , Schwartz René , Hintze Thomas 
Published: June 2006

AbstractTracer experiments were carried out in groyne fields (GF) of the river Elbe near Havelberg (Germany) in order to estimate the hydraulic connectivity with the river channel. The characteristic times of the five groyne fields, which were estimated from the exponentially declining tracer curves in 43 runs, ranged between 15 min and 69 min and did not correlate with the water level. Methodological investigations show that single point injection and two measurements (in the outflowing water and in the dominant region) are sufficient to provide robust in‐situ tracer curves. Using simplified mathematical simulations with connected stirred tanks, the conditions are investigated for the development of breaks in tracer curves and for the occurrence of significant errors in the estimation of intrinsic residence times. It was shown that an initial uniform dye distribution is not mandatory for the estimation during steady states. In special cases, point injections are more advisable. Moreover, the mean hydraulic residence time was found to be not equivalent to the estimated characteristic time. In fact, it is mostly overestimated by tracer experiments. The degree of overestimation depends on mixing and the volumetric proportions between the different parts of the GF and can be calculated from measured dye concentration differences. For example, an overestimation of 32% was calculated for a groyne field with a commonly found circulation flow pattern.
Tetanus antibody titers and duration of immunity to clinical tetanus infections in free‐ranging rhesus monkeys (Macaca mulatta)
Authors: Kessler Matthew J. , Berard John D. , Rawlins Richard G. , Bercovitch Fred B. , Gerald Melissa S. , Laudenslager Mark L. , Gonzalez‐Martinez Janis 
Published: June 2006

AbstractPrior to 1985 tetanus was a major cause of mortality in the free‐ranging colony of rhesus monkeys on Cayo Santiago, accounting for almost a quarter of annual deaths. In 1985 and 1986 all animals (except infants) received primary and booster doses, respectively, of tetanus toxoid. In subsequent years primary immunizations were given to all yearlings, and boosters were administered to all 2‐year‐old animals during the annual capture of the colony. The main objectives of the tetanus immunization program were to reduce the pain and suffering caused by tetanus infections and to decrease mortality in the colony. Other objectives were to evaluate the efficacy of the two‐dose tetanus toxoid immunization protocol and to determine whether additional boosters might be required to provide adequate long‐term protection against tetanus infections. The immediate effect of the mass immunization program was the elimination of clinical tetanus infections in the population and a 42.2% reduction in the overall mortality rate. Since the immunization program began, no cases of tetanus have been observed in the colony, except in two unimmunized infants, and it has not been necessary to give tertiary injections of tetanus toxoid to maintain protection against infection. A sample collected in 2004 of the original cohort of monkeys immunized in 1985 and 1986 showed that 93.3% (14/15) had protective tetanus antibody titers (>0.01 IU/ml) at the ages of 20–23 years, which is close to the life expectancy of the Cayo Santiago rhesus macaques. Two intramuscular doses of tetanus toxoid provided long‐term, if not lifelong, protection against tetanus for rhesus monkeys living in a tropical clime where tetanus is enzootic and the risk of infection is great. Am. J. Primatol. 68:725–731, 2006.© 2006 Wiley‐Liss, Inc.
Bed‐building in captive chimpanzees (Pan troglodytes): the importance of early rearing
Authors: Videan Elaine N. 
Published: June 2006

AbstractIn the wild, great apes sleep in beds they make by successively bending branches into an interwoven platform. These beds are functionally more closely related to human beds than they are to the nests and tree‐holes used by other primate species. The idea that bed‐building by great apes is learned behavior that is dependent on appropriate early experiences has been proposed but never fully tested. In the present study this hypothesis was indirectly tested in 73 captive adult chimpanzees (Pan troglodytes; 27 wild‐born and 46 captive‐born). Bed‐building and use were tested experimentally by the introduction of three sets of bedding materials. Over 200 hr of scan‐sampling data were collected during 45‐min observations following introduction of the bedding material. The wild‐born subjects built and used beds significantly more often than the captive‐born subjects. Also, wild‐born subjects used more complex techniques during construction. Captive‐born subjects that were mother‐reared through early adolescence spent more time building and using beds than their nursery‐reared counterparts. These differences remained consistent even when previous adult experience with bedding (measured as naturalistic vs. traditional housing) was accounted for. These results suggest that bed‐building is a learned behavior that requires early experience and practice for acquisition. Am. J. Primatol. 68:745–751, 2006. © 2006 Wiley‐Liss, Inc.
New approach to antibacterial treatment of cotton fabric with silver nanoparticle–doped silica using sol–gel process
Authors: Tarimala Sowmitri , Kothari Neha , Abidi Noureddine , Hequet Eric , Fralick Joe , Dai Lenore L. 
Published: June 2006

AbstractIn this study, cotton fabric was successfully modified to have an antibacterial property through use of the sol–gel process. Dodecanethiol‐capped silver nanoparticles, which have powerful antibacterial activity, were incorporated in silica sol. The starting materials were silver nitrate, tetraoctylammonium bromide, sodium borohydride, chloroform, 1‐dodecanethiol, ethanol, tetraethylorthosilicate, and water. The cotton fabric was padded with dodecanethiol‐capped silver nanoparticle–doped sol, dried at 60°C, and cured at 150°C. Scanning electron microscopy showed a uniform and continuous layer of doped sol on the fiber surface. The antibacterial effects of the treated cotton fabric against Escherichia coli were examined and found to be excellent. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101:2938–2943, 2006
Morphology of polyvinylidene fluoride and its blend in thermally induced phase separation process
Authors: Li Xianfeng , Lu Xiaolong 
Published: June 2006

AbstractPolyvinylidene fluoride (PVDF) and its blend films were prepared by melt‐blending the binary mixture of PVDF/dibutyl phthalate (DBP) and the ternary mixture of PVDF/CaCO3/DBP in combination of TIPS. Their morphologies were characterized by scanning electron microscope depended on preparation condition, such as the diluent and CaCO3 weight fraction, and the cooling rate, and the crystallization information was also investigated by DSC. The results showed that CaCO3 influenced the morphology of PVDF in the TIPS process regardless of the cooling conditions, and the formation of the spherulitic morphology can be disturbed by CaCO3 at the quenching condition. The effect of CaCO3 weight fraction on the tensile strength of PVDF was measured, which indicated CaCO3 had a negative effect on PVDF tensile strength. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2944–2952, 2006
Study on the rheological behavior of the hydrophobically modified hydroxyethyl cellulose with 1,2‐epoxyhexadecane*
Authors: Ye Lin , Li Qin , Huang Ronghua 
Published: June 2006

AbstractThrough the macromolecule reaction method, the hydrophobically modified hydroxyethyl cellulose (EP16–HAHEC) was synthesized using 1, 2‐epoxyhexadecane as the hydrophobic monomer. The solution properties of EP16–HAHEC were comprehensively investigated, which showed that the polymer with enhanced; viscosification property, thermal stability, shear resistance, and salt resistance was obtained. Amphiphilic structure of EP16–HAHEC molecules contributed to the surface activity of the polymer. By forming complex solution with surfactants or carboxylmethyl cellulose (CMC), the viscosification property of EP16–HAHEC could be enhanced through the interactions of hydrophobic groups and hydrogen bonds. The viscosity‐enhancing mechanism of HAHEC was studied by the environment scan electronic microscope (ESEM) and the fluorescence spectrum measurements, which demonstrated that the formation of the supramolecular aggregation networks was coincident with the increase of the apparent viscosity of HAHEC. With the gradual formation of the complete polymer molecule networks, the apparent viscosity rised dramatically, and the associating aggregations of the polymer molecules appeared far before the great change of the macroproperty of the polymer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2953–2959, 2006
HEMA‐grafted chitosan for dialysis membrane applications
Authors: Radhakumary C. , Nair Prabha D. , Mathew Suresh , Nair C. P. Reghunadhan 
Published: June 2006

AbstractChitosan was graft copolymerized with HEMA (2‐Hydroxyethylmethacrylate) for the development of blood‐compatible dialysis membranes. The permeation characteristics of HEMA‐grafted chitosan films for four different solutes creatinine, urea, glucose, and albumin was studied in vitro at 37°C for assessment of the suitability as dialysis membranes. The grafted film CH‐12.5 composition (425% grafting) showed very high permeation to creatinine by reaching the equilibrium within 45 min. The compositions CH‐7.5 and CH‐12.5 showed excellent permeation to glucose when compared to virgin chitosan films. In the case of urea permeation, all the grafted compositions exhibited higher percent permeation than the virgin chitosan films. The copolymer films CH‐7.5 and CH‐12.5 showed enhanced permeability for the high molecular weight solute, albumin. The other grafted copolymer compositions followed almost the same trend as that of chitosan for the low molecular weight solutes as well as the high molecular weight solute. The copolymer films were also found to be highly blood compatible, noncytotoxic, and biodegradable. Hence, the need for developing blood‐compatible chitosan membranes with desirable permeability properties is achieved by the graft copolymerization of HEMA onto chitosan. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2960–2966, 2006
Poly(methacrylamide‐co‐acrylic acid) hydrogels for gastrointestinal delivery of theophylline. I. Swelling characterization
Authors: Dubey Seema , Bajpai S. K. 
Published: June 2006

AbstractpH sensitive copolymeric hydrogels have been synthesized by free‐radical polymerization of methacrylamide and acrylic acid in aqueous medium. The gels were characterized by FTIR spectroscopy, thermogravimetric analysis, and swelling measurements. To determine the suitability of theses hydrogels for gastrointestinal oral delivery of model drug theophylline, their swelling behavior was investigated as a function of pH and various structural parameters such as the average molecular weight between crosslinks, crosslink density, and mesh size were calculated. Likewise initial, average and late time diffusion coefficients were also evaluated in simulating intestinal fluid of pH 6.8 at 37°C. The gel underwent sharp volume phase transition in the vicinity of pH 5.8. The mesh sizes of the hydrogel were between 8.4 and 9.2 Å in the collapsed state (pH range 1–2; SGF) and between 514 and 524 Å in the swollen state (pH range 7–8; SIF). The experimental data was found to fit well to Beren‐Hopfenberg equation thus suggesting that later part of swelling was chain relaxation controlled. The activation energy, as determined from Arrhenius equation was found to be 13.71 kJ mol−1. Likewise, enthalpy of mixing was also evaluated using Gibbs‐Helmholtz equation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2995–3008, 2006
Functionalization of low‐molecular‐weight oligomer dienes and olefins with sulfur‐ and oxygen‐containing compounds
Authors: Biglova R. Z. , Galimzyanova A. U. , Dokichev V. A. , Konesev G. V. , Zaikov G. E. , Talipov R. F. 
Published: June 2006

AbstractThe functionalization of piperylene fractions, oligodienes, and oligo‐olefins by elemental sulfur and phenols was carried out. The functionalized compounds were shown to be multipurpose additives, exhibiting high antiwear and antiscuff properties and simultaneously antioxidant and viscous properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3097–3105, 2006
Effects of metallic monomer powders on the mechanical properties of hardened polyester and acrylic polymer concrete
Authors: Ahn Namshik 
Published: June 2006

AbstractTo investigate the effects of three metallic monomer powders on polyester‐ and acrylic‐hardened polymer concretes, polymer concretes incorporating different levels of these materials were investigated for the properties of hardened polymer concrete. The mix design was made and optimized for workability and strength, depending on the resin viscosity, the intended use, and the additional quantities of these polymeric materials. The investigated properties included the compressive strength, flexural strength, and bond strength of hardened polymer concrete. It was concluded that these polymeric materials offer the possibility of improving the properties of polyester‐ and acrylic‐hardened polymer concretes. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3106–3113, 2006
Self‐assembled honeycomb polyurethane nanofibers
Authors: Thandavamoorthy S. , Gopinath N. , Ramkumar S. S. 
Published: June 2006

AbstractElectrospinning uses a high voltage electric field to produce fine fibers. A new phenomenon of self‐assembly in the electrospinning of polyurethane nanofibers is observed. This report is the first known self‐assembling phenomenon in polyurethane electrospun nanofibers. Electrospun polyurethane nanofibers self‐assemble into unique honeycomb patterns on the collector surface. This novel observation opens up new and interesting opportunities for electrospun fibers in the areas of drug delivery devices, protective clothing, filters, and tissue scaffolds. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3121–3124, 2006