bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heterozygous Insertions Alter Crossover Distribution but Allow Crossover Interference in Caenorhabditis elegans
Authors: Hammarlund Marc , Davis M Wayne , Nguyen Hung , Dayton Dustin , Jorgensen Erik M 
Published: August 2005

Abstract
The normal distribution of crossover events on meiotic bivalents depends on homolog recognition, alignment, and interference. We developed a method for precisely locating all crossovers on Caenorhabditis elegans chromosomes and demonstrated that wild-type animals have essentially complete interference, with each bivalent receiving one and only one crossover. A physical break in one homolog has previously been shown to disrupt interference, suggesting that some aspect of bivalent structure is required for interference. We measured the distribution of crossovers in animals heterozygous for a large insertion to determine whether a break in sequence homology would have the same effect as a physical break. Insertions disrupt crossing over locally. However, every bivalent still experiences essentially one and only one crossover, suggesting that interference can act across a large gap in homology. Although insertions did not affect crossover number, they did have an effect on crossover distribution. Crossing over was consistently higher on the side of the chromosome bearing the homolog recognition region and lower on the other side of the chromosome. We suggest that nonhomologous sequences cause heterosynapsis, which disrupts crossovers along the distal chromosome, even when those regions contain sequences that could otherwise align. However, because crossovers are not completely eliminated distal to insertions, we propose that alignment can be reestablished after a megabase-scale gap in sequence homology.
TFIID and Spt-Ada-Gcn5-Acetyltransferase Functions Probed by Genome-wide Synthetic Genetic Array Analysis Using a Saccharomyces cerevisiae taf9-ts Allele
Authors: Milgrom Elena , West Robert W , Gao Chen , Shen W-C Winston 
Published: August 2005

Abstract
TAF9 is a TATA-binding protein associated factor (TAF) conserved from yeast to humans and shared by two transcription coactivator complexes, TFIID and SAGA. The essentiality of the TAFs has made it difficult to ascertain their roles in TFIID and SAGA function. Here we performed a genomic synthetic genetic array analysis using a temperature-sensitive allele of TAF9 as a query. Results from this experiment showed that TAF9 interacts genetically with: (1) genes for multiple transcription factor complexes predominantly involving Mediator, chromatin modification/remodeling complexes, and regulators of transcription elongation; (2) virtually all nonessential genes encoding subunits of the SWR-C chromatin-remodeling complex and both TAF9 and SWR-C required for expressing the essential housekeeping gene RPS5; and (3) key genes for cell cycle control at the G1/S transition, as well as genes involved in cell polarity, cell integrity, and protein synthesis, suggesting a link between TAF9 function and cell growth control. We also showed that disruption of SAGA by deletion of SPT20 alters histone-DNA contacts and phosphorylated forms of RNA polymerase II at coding sequences. Our results raise the possibility of an unappreciated role for TAF9 in transcription elongation, perhaps in the context of SAGA, and provide further support for TAF9 involvement in cell cycle progression and growth control.
Saccharomyces cerevisiae Ub-Conjugating Enzyme Ubc4 Binds the Proteasome in the Presence of Translationally Damaged Proteins
Authors: Chuang Show-Mei , Madura Kiran 
Published: August 2005

Abstract
Surveillance mechanisms that monitor protein synthesis can promote rapid elimination of misfolded nascent proteins. We showed that the translation elongation factor eEF1A and the proteasome subunit Rpt1 play a central role in the translocation of nascent-damaged proteins to the proteasome. We show here that multiubiquitinated proteins, and the ubiquitin-conjugating (E2) enzyme Ubc4, are rapidly detected in the proteasome following translational damage. However, Ubc4 levels in the proteasome were reduced significantly in a strain that expressed a mutant Rpt1 subunit. Ubc4 and Ubc5 are functionally redundant E2 enzymes that represent ideal candidates for ubiquitinating damaged nascent proteins because they lack significant substrate specificity, are required for the degradation of bulk, damaged proteins, and contribute to cellular stress-tolerance mechanisms. In agreement with this hypothesis, we determined that ubc4Δ ubc5Δ is exceedingly sensitive to protein translation inhibitors. Collectively, these studies suggest a specific role for Ubc4 and Ubc5 in the degradation of cotranslationally damaged proteins that are targeted to the proteasome.
A Markov Chain Monte Carlo Technique for Identification of Combinations of Allelic Variants Underlying Complex Diseases in Humans
Authors: Favorov Alexander V , Andreewski Timophey V , Sudomoina Marina A , Favorova Olga O , Parmigiani Giovanni , Ochs Michael F 
Published: August 2005

AbstractIn recent years, the number of studies focusing on the genetic basis of common disorders with a complex mode of inheritance, in which multiple genes of small effect are involved, has been steadily increasing. An improved methodology to identify the cumulative contribution of several polymorphous genes would accelerate our understanding of their importance in disease susceptibility and our ability to develop new treatments. A critical bottleneck is the inability of standard statistical approaches, developed for relatively modest predictor sets, to achieve power in the face of the enormous growth in our knowledge of genomics. The inability is due to the combinatorial complexity arising in searches for multiple interacting genes. Similar “curse of dimensionality” problems have arisen in other fields, and Bayesian statistical approaches coupled to Markov chain Monte Carlo (MCMC) techniques have led to significant improvements in understanding. We present here an algorithm, APSampler, for the exploration of potential combinations of allelic variations positively or negatively associated with a disease or with a phenotype. The algorithm relies on the rank comparison of phenotype for individuals with and without specific patterns (i.e., combinations of allelic variants) isolated in genetic backgrounds matched for the remaining significant patterns. It constructs a Markov chain to sample only potentially significant variants, minimizing the potential of large data sets to overwhelm the search. We tested APSampler on a simulated data set and on a case-control MS (multiple sclerosis) study for ethnic Russians. For the simulated data, the algorithm identified all the phenotype-associated allele combinations coded into the data and, for the MS data, it replicated the previously known findings.
Spectral Properties of Pro‐multimodal Imaging Agents Derived from a NIR Dye and a Metal Chelator
Authors: Zhang Zongren , Achilefu Samuel 
Published: August 2005

ABSTRACTMonomolecular multimodal imaging agents (MOMIAs) are able to provide complementary diagnostic information of a target diseased tissue. We developed a convenient solid‐phase approach to construct two pro‐MOMIAs (before incorporating radiometal) derived from 1,4,7,10‐tetraazacy‐clododecane‐1,4,7,10‐tetraacetic acid (DOTA) and cypate, a near‐infrared (NIR) fluorescent dye analogous to indocyanine green (ICG). The possible interaction between d orbitals of transition metal DOTA complexes or free metals and the p orbitals of cypate chromophore could quench the fluorescence of pro‐MOMIAs. However, we did not observe significant changes in the spectral properties of cypate upon conjugation with DOTA and subsequent chelation with metals. The fluorescence intensity of the chelated and nonmetal‐chelated PRO‐MOMIAs remained fairly the same in dilute 20% aqueous dimethylsulfoxide (DMSO) solution (1 × 10−6M). Significant reduction in the fluorescence intensity of pro‐MOMIAs occurred in the presence of a large excess of metal ions (> 1 molar ratio for indium and 20‐fold for a copper relative to pro‐MOMIA). This study suggests the feasibility of using MOMIAs for combined optical and radioisotope imaging.
Highly Efficient Non‐Doped Blue Organic Light‐Emitting Diodes Based on Fluorene Derivatives with High Thermal Stability
Authors: Tao S. L. , Peng Z. K. , Zhang X. H. , Wang P. F. , Lee C.‐S. , Lee S.‐T. 
Published: August 2005

AbstractA new series of blue‐light‐emitting fluorene derivatives have been synthesized and characterized. The fluorene derivatives have high fluorescence yields, good thermal stability, and high glass‐transition temperatures in the range 145–193 °C. Organic light‐emitting diodes (OLEDs) fabricated using the fluorene derivatives as the host emitter show high efficiency (up to 5.3 cd A–1 and 3.0 lm W–1) and bright blue‐light emission (Commission Internationale de L'Eclairage (CIE) coordinates of x = 0.16, y = 0.22). The performance of the non‐doped fluorene‐based devices is among the best fluorescent blue‐light‐emitting OLEDs. The good performance of the present blue OLEDs is considered to derive from: 1) appropriate energy levels of the fluorene derivatives for good carrier injection; 2) good carrier‐transporting properties; and 3) high fluorescence efficiency of the fluorene derivatives. These merits are discussed in terms of the molecular structures.
The effect of ligand type and density on osteoblast adhesion, proliferation, and matrix mineralization
Authors: Harbers Gregory M. , Healy Kevin E. 
Published: August 2005

AbstractPolystyrene surfaces grafted with a nonfouling interfacial interpenetrating polymer network (IPN) of poly(acrylamide‐co‐ethylene glycol/acrylic acid) [p(AAm‐co‐EG/AAc)] were modified with several peptide ligands adapted from bone sialoprotein (BSP). IPNs were modified with both single ligands and ligand blends to study the correlation between a simple metric, ligand–receptor adhesion strength, and the extent of matrix mineralization for osteoblast like cells (rat calvarial osteoblasts). The ligands studied included RGD cell‐binding [CGGNGEPRGDTYRAY (l‐RGD), CGGEPRGDTYRA (s2‐RGD), CGPRGDTYG (lc‐RGD), cyclic(CGPRGDTYG) (c‐RGD), and CGGPRGDT (s‐RGD)], heparin binding (CGGFHRRIKA), and collagen binding (CGGDGEAG) peptides, with the appropriate controls. Adhesion strength scaled with ligand density (1–20 pmol/cm2) and was dependent on ligand type with the following trend: l‐RGD > s2‐RGD ≈ c‐RGD >> s‐RGD ≈ lc‐RGD >>> FHRRIKA ≈ DGEA. Independent of ligand density, % matrix mineralization varied with ligand type resulting in the following trend: lc‐RGD > s2‐RGD > l‐RGD ≈ c‐RGD >> s‐RGD >>> FHRRIKA. The Tyr (Y) residue immediately following the RGD cell‐binding domain proved to be critical for stable cell proliferation and mineralization, since removal of this residue resulted in erratic cell attachment and mineralization behavior. The minimum BSP sequence necessary for strong adhesion and extensive mineralization was CGGEPRGDTYRA; the minimal sequence suitable for extensive mineralization but lacking strong adhesion was CGPRGDTYG. The cyclic peptide (c‐RGD) had much greater adhesion strength compared to its linear counterpart (lc‐RGD). The calculated characteristic adhesion strength (F70) obtained using a centrifuge adhesion assay proved to be a poor metric for predicting % mineralized area; however, in general, surfaces possessing a F70 > 100g promoted extensive matrix mineralization. Percent mineralization and number of mineralized nodules scaled with number of cells seeded suggesting a critical dependence on the initial number of osteoprogenitors in culture. This study demonstrates matrix mineralization dependence on ligand type, ligand density, and adhesion strength. The high‐throughput character of these surfaces allowed efficient investigation of multiple ligands at multiple densities providing an excellent tool for studying ligand–receptor interactions under normal cell culture conditions with serum present. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Effects of porosity and pore size on in vitro degradation of three‐dimensional porous poly(D,L‐lactide‐co‐glycolide) scaffolds for tissue engineering
Authors: Wu Linbo , Ding Jiandong 
Published: August 2005

AbstractIn vitro degradation of seven three‐dimensional porous scaffolds composed of PLGA85/15, a very useful poly(D,L‐lactide‐co‐glycolide), was performed in phosphate‐buffered saline solution at 37°C up to 26 weeks, and effects of porosity (80–95%) and pore size (50–450 μm) on the degradation of the scaffolds were investigated. A series of quantities were measured during the degradation processes: molecular weight and its distribution of PLGA; compressive strength and modulus; and weight, dimension, and porosity of scaffolds. In all of cases with different pore morphologies, the degradation processes obeyed a three‐stage model. Scaffolds with a higher porosity or a smaller pore size degraded more slowly than and thus outlasted those with a lower porosity or a larger pore size. The effects are both attributed to a wall effect and a surface area effect because the scaffolds with lower porosities or larger pores possess thicker pore walls and smaller surface area, which depress the diffusion of acidic degradation products and thus results in a stronger acid‐catalyzed hydrolysis. This work suggests that, in designing a tissue‐engineering scaffold composed of PLGA and adjusting its degradation rate, the effects of pore morphologies should be taken into consideration in addition to those of chemical composition and condensed state of raw materials. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Elation Laguerre planes of order 16 are ovoidal
Authors: Steinke Günter F. 
Published: August 2005

AbstractWe conduct a computer search for elation Laguerre planes of order 16 and show that each such plane is ovoidal. The search results also confirm the numbers of hyperovals through certain points in the dual translation planes of order 16 given in [15]. © 2005 Wiley Periodicals, Inc. J Combin Designs 14: 313–323, 2006
Renal sexual segment of the ground skink, Scincella laterale (Reptilia, Squamata, Scincidae)
Authors: Sever David M. , Hopkins William A. 
Published: August 2005

AbstractMature squamates possess hypertrophied regions of the distal urinary ducts, the renal sexual segment (RSS). The RSS is believed to provide seminal fluid that mixes with sperm and is released into the female cloaca during coitus. This study is the first to describe ultrastructure of the RSS in a lizard collected throughout the active season. The species examined, Scincella laterale, represents the largest family (Scincidae: 1,200 species) of lizards. Although sperm are present in the posterior ductus deferens of male S. laterale throughout the year, an annual spermatogenic cycle occurs that results in spermiation in spring, coinciding with maximum development of the RSS. Female S. laterale may possess stored sperm in vaginal crypts from March–May and large oviductal eggs April–June. Thus, the correlation between mating and RSS activity observed in other squamates is also found in S. laterale. Cytologically, the active RSS consists of columnar cells with numerous apical, electron‐dense secretory vacuoles which are released by an apocrine process. The granules stain positively for proteins with bromphenol blue and react with PAS for neutral carbohydrates. After the mating season the RSS undergoes recrudescence and the electron‐dense granules are replaced by a mucoid secretion that characterizes more proximal portions of the nephric tubules throughout the year. Little variation in ultrastructure of the RSS occurs between S. laterale and Cnemidophorus lemniscatus (Teiidae), the only other lizard in which seasonal variation of the RSS has been studied using similar methods. Females exhibit differentiation similar to that of males in the distal urinary tubules, but to a lesser degree. This is only the second such report for female squamates, and the differentiation of the region in females is proposed to result from adrenal androgens. J. Morphol. Published 2005 Wiley‐Liss, Inc.
Gastrointestinal stromal tumor involving the second and third portion of the duodenum: Treatment by partial duodenectomy and Roux‐en‐Y duodenojejunostomy
Authors: Goh Brian K.P. , Chow Pierce K.H. , Ong Hock‐Soo , Wong Wai‐Keong 
Published: August 2005

AbstractThe optimal surgical procedure for duodenal gastrointestinal tumors (GIST) remains undefined because while surgical resection clearly confers survival advantage, there is little submucosal spread in GIST and lymphatic involvement is rare. Various surgical procedures for duodenal GIST, pancreatoduodenectomy, pancreas‐sparing duodenectomy, segmental duodenectomy, or local resection, have been described depending on the size and exact site of the lesion. In this report, we describe two cases of GIST involving the second and third portion of the duodenum successfully treated by partial duodenectomy with Roux‐en‐Y duodenojejunostomy. This surgical technique is ideal when GIST does not involve the ampulla as it avoids a pancreatoduodenectomy and has not been previously described for the management of this malignancy. J. Surg. Oncol. 2005;91:273–275. © 2005 Wiley‐Liss, Inc.
Personal resources, coping self‐efficacy, and quake exposure as predictors of psychological distress following the 1999 earthquake in Turkey
Authors: Sumer Nebi , Karanci A. Nuray , Berument Sibel Kazak , Gunes Hatice 
Published: August 2005

AbstractThis study examined the predictive power of personal resources (i.e., self‐esteem, optimism, and perceived control), severity of earthquake experience (i.e., material and human loss and perceived threat), and coping self‐efficacy (CSE) on general distress, intrusion, and avoidance symptoms among the survivors of the 1999 Marmara earthquake in Turkey. Specifically, we expected that CSE would mediate the links between personal resources, severity of earthquake experience, and distress. Survivors (N = 336) filled out various measures of earthquake exposure, personal resources, CSE, and distress. Results of the path analyses indicated that personal resources, earthquake experiences, CSE, and gender have direct effects on intrusion and general distress. Personal resources had also an indirect effect on general distress mediated by CSE. Findings were discussed considering the implications for conservation of resources model and social cognitive theory as well as for interventions following natural disasters.
Multilayer Capsules with Cell‐like Topology: Fabrication and Spontaneous Loading of Various Substances in Aqueous and Ethanol Solutions
Authors: Tong Weijun , Dong Wenfei , Gao Changyou , Möhwald Helmuth 
Published: August 2005

AbstractSummary: Multilayer microcapsules are fabricated by layer‐by‐layer assembly of sodium poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) on porous CaCO3 microparticles, followed by removal of the sacrificial template. Confocal microscopy (CLSM) reveals that the obtained capsules have polyelectrolyte complex cores, which connect with the shells through polyelectrolyte complex fibers (so called cell‐like topology). The complex is composed of PSS and PAH bound by electrostatic interaction during the assembly procedure, as evidenced by confocal Raman image. CLSM characterization demonstrates that positively charged rhodamine 6G, neutral Nile red and negatively charged 6‐carboxyfluorescein can all be spontaneously encapsulated either in aqueous or in ethanol solution.CLSM images of the cell‐like microcapsule.magnified imageCLSM images of the cell‐like microcapsule.
Anisotropic Dimensional Swelling of Membranes of Ultrafine Hydrogel Fibers
Authors: Jin Xing , Hsieh You‐Lo 
Published: August 2005

AbstractSummary: Interconnecting fibrous membranes were generated by electrospinning an aqueous mixture of poly(acrylic acid) and poly(vinyl alcohol) at a 3.5 COOH/OH molar ratio. The membranes containing 200 to 500 nm diameter fibers were crosslinked by heat‐induced esterification and behaved like anionic hydrogels, i.e., they swelled significantly more at a pH above 4. The dimensional expansion of these fibrous membranes was far greater in their thickness than in their planar areas. The anisotropic dimensional expansion was associated with the spatial arrangement of fibers, i.e., much smaller inter‐fiber spaces along the thickness direction than in the planar directions. Crosslinking under constraint caused further fiber compaction in the thickness direction, leading to anisotropic and accordion‐like dimensional expansion upon swelling.SEM image of the PAA/PVA membrane (C1) thermally crosslinked under high constraint.magnified imageSEM image of the PAA/PVA membrane (C1) thermally crosslinked under high constraint.
Photodeformable Polymers: A New Kind of Promising Smart Material for Micro‐ and Nano‐Applications
Authors: Yu Yanlei , Ikeda Tomiki 
Published: August 2005

AbstractSummary: Starting in the 1960s, several kinds of photodeformable polymers have been developed, such as monolayers, polymer gels, solid films and liquid‐crystalline elastomers with different photodeformation mechanisms. This field evolved slowly until recently when significant achievements have been made. Most recently, Lendlein and co‐workers have put forward another new concept – using photo‐crosslinking to prepare deformable polymers with various pre‐determined shapes (Nature 2005, 434, 879). This highlight gives a general introduction into photodeformable polymers and brings forth future challenges.A polymer film doped with SCAA molecules where (a) is the permanent shape, (b) is the temporary shape and (c) is the recovered shape.magnified imageA polymer film doped with SCAA molecules where (a) is the permanent shape, (b) is the temporary shape and (c) is the recovered shape.
Factors affecting the complexation of polyacrylic acid with uranyl ions in aqueous solutions: A luminescence study
Authors: Dubolazov Artem V. , Güven Olgun , Pekel Nursel , Mun Grigoriy A. , Nurkeeva Zauresh S. 
Published: August 2005

AbstractA study was carried out in aqueous solutions using luminescence technique to investigate the effects of pH, salt concentration, and temperature on the polyacrylic acid/uranyl ion (PAA/UO) complex formation as well as competitive phenomena of enhancement and quenching effects on photoexcited state of uranyl ions. It was found that excess of H+ and OH− is not favorable for complexation between uranyl ions and polymer. Added nitrate salts of Na+ and K+ had significant enhancement effect on emission spectra of PAA/UO complex. These results indicated that the metal ion/polymer chain complex collapsed by addition of salts and then complex became more compact with consequent phase separation. No significant effect of temperature on the PAA/UO complex stability has been observed between 25–50 °C. The quenching rate constants obtained from Stern–Volmer plots were found to be in the order of kq(H+) >> kq(K+) > kq(Na+). © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2737–2744, 2005