bluuebunny/crossref_metadata_2025_split huggingface dataset:
Predicting the connectivity of primate cortical networks from topological and spatial node properties
Authors: Costa Lucianoda F , Kaiser Marcus , Hilgetag Claus C 
Published: March 2007

Abstract

Background
The organization of the connectivity between mammalian cortical areas has become a major subject of study, because of its important role in scaffolding the macroscopic aspects of animal behavior and intelligence. In this study we present a computational reconstruction approach to the problem of network organization, by considering the topological and spatial features of each area in the primate cerebral cortex as subsidy for the reconstruction of the global cortical network connectivity. Starting with all areas being disconnected, pairs of areas with similar sets of features are linked together, in an attempt to recover the original network structure.

Results
Inferring primate cortical connectivity from the properties of the nodes, remarkably good reconstructions of the global network organization could be obtained, with the topological features allowing slightly superior accuracy to the spatial ones. Analogous reconstruction attempts for the C. elegans neuronal network resulted in substantially poorer recovery, indicating that cortical area interconnections are relatively stronger related to the considered topological and spatial properties than neuronal projections in the nematode.

Conclusion
The close relationship between area-based features and global connectivity may hint on developmental rules and constraints for cortical networks. Particularly, differences between the predictions from topological and spatial properties, together with the poorer recovery resulting from spatial properties, indicate that the organization of cortical networks is not entirely determined by spatial constraints.
Volume and Lipid, Fatty Acid, and Amino Acid Composition of Golden Shiner Eggs during a Spawning Season
Authors: Lochmann S E , Goodwin K J , Lochmann R T , Stone N M , Clemment T 
Published: March 2007

Abstract
The Arkansas baitfish industry leads the nation in production of golden shiners Notemigonus crysoleucas. To determine nutritional requirements for golden shiner broodstock diets, we examined the volume and lipid, fatty acid, and amino acid composition of the eggs produced by a group of captive broodstock over a spawning season. Egg volume was 0.67 ± 0.117 mm3 (mean ± SD); egg volume declined during the spawning season. Total lipid was 15.67 ± 2.99 μg/egg, and triacylglyceride (TAG) concentration was 6.82 ± 1.81 μg/egg. Based on the stability of egg total lipid, the percent neutral lipid, the consistent contribution of TAG to neutral lipid, the consistent TAG concentration, and the stable fatty acid and amino acid profiles, we conclude that the lipid and amino acids in eggs from the experimental group were stable. The eggs should be equally sufficient for embryological development throughout the spawning season, but specific indices of egg and fry quality must be measured to confirm the links among egg size, biochemical composition, and egg and fry quality.
Captive Survival and Pearl Culture Potential of the Pink Heelsplitter Potamilus alatus
Authors: Hua Dan , Neves Richard J 
Published: March 2007

Abstract
Pink heelsplitter mussels Potamilus alatus were held at two bottom locations and suspended in pocket nets in a pond at the Freshwater Mollusk Conservation Center, Virginia Polytechnic Institute and State University, for 1 year to evaluate survival in captivity. Survival after 1 year differed significantly; the poorest survival (30.0%) was at the bottom of the deep end (2.5 m), and there was no difference in survival) at the shallow end (83.3%; 0.6 m) and in pocket nets (63.3%; 1–1.5 m). Monthly survival was inversely related to water temperature (R = −0.72); the lowest monthly survival occurred in summer, resulting in a significant difference among the three locations. Differences in the mean glycogen content of mussels among the three containment locations and wild-sampled pink heelsplitter mussels were significant (P = 0.001); the highest value was in mussels at the shallow end and the lowest value was in mussels at the deep end. We used pocket nets to hold surgically implanted mussels and measured glycogen reserves to monitor body condition and assess the potential of the pink heelsplitter mussel to produce nonnucleated and image pearls. Results of the pearl culture experiment in two ponds showed that nonnucleated pearls and image pearls with purple or purplish luster were successfully produced. There was no significant difference in pearl weight in mussels held in the two experimental ponds under different environmental conditions. Similarly, no differences in monthly survival rates of mussels were observed in either pond or among mussels with surgical implants and the no-surgery control mussels. Therefore, pink heelsplitter mussels can be considered a potentially suitable species for producing purple pearls in farm pond environments.
Seasonal Variation of Sperm Quality and the Relationship between Spermatocrit and Sperm Concentration in Yamú Brycon amazonicus
Authors: Cruz-Casallas Pablo E , Medina-Robles Víctor M , Velasco-Santamaría Yohana M 
Published: March 2007

Abstract
Osmolality, the concentrations of glucose, total cholesterol, and triglyceride, and the concentrations of ions such as Na+, Cl−, K+, and Mg2+ in the seminal plasma of yamú Brycon amazonicus were evaluated during one reproductive season. Semen quality and the relationship between spermatocrit and sperm concentration were examined over two reproductive seasons. Activation time, spermatocrit, and sperm concentration were significantly higher in 2003 than in 2004. Spermatocrit and sperm concentration showed a significant positive relationship (r 2 = 0.79). During the 2004 reproductive season, a significant variation was observed for spermatocrit and sperm concentration between the initial period (February 15th to March 14th) and the middle and final periods (March 15th to April 14th and April 15th to May 14th, respectively). Neither the ion concentrations nor the glucose and cholesterol concentrations varied between any periods of the reproductive season. Osmolality and triglyceride concentrations showed significant variations between periods during the reproductive season.
Structural and Electronic Properties of the First Monolayers of Spin‐Cast Poly(fluorene)‐Based Conjugated‐ Polymer Films
Authors: Plank H. , Güntner R. , Scherf U. , List E. J. W. 
Published: March 2007

AbstractThis study is an extended investigation on the formation of the first few monolayers of conjugated poly(fluorene)‐based polymer films prepared from solution on defined polar and nonpolar surfaces. In particular, a symmetrical A–B–A triblock copolymer consisting of poly(2‐alkylaniline) as A blocks and poly(9,9‐dialkylfluorene) as B blocks and a poly(9,9‐dialkylfluorene) homopolymer is used for this study. The dependence on drying conditions by means of solvent selection, the influence of a subsequent heat treatment, and the influence of the substrate polarity are investigated for ultrathin films as well as the transition from the first monolayers to the bulk polymer. The study is performed with optical absorption and photoluminescence spectroscopy, and atomic force microscopy to obtain complementary information of optical properties and morphological details. We find that ultrathin films (ca. 1–2 nm) prepared on mica from various solvents form highly defined, flat monolayers at the interface without lateral regularities indicating a dipole–dipole interaction between conjugated‐polymer segments and mica surface dipoles. This is further confirmed by bathochromic photoluminescence shifts observed for the ultrathin layers compared to the bulk polymer. Complementary experiments on nonpolar surfaces, highly oriented pyrolytic graphite (HOPG), show a total absence of defined flat films supporting the assumption of a dipole–dipole assisted formation on mica. For increased film thickness on mica (5 nm and more) the homopolymer does not form any regular structures or ordered layers on top of the monolayer. In contrast, the triblock copolymer, shorter in length, revealed a tendency to form a less‐defined layer‐type growth (3–3.5 nm thick) above the monolayer that was of higher order for higher‐boiling‐point solvents, indicating that the polymers are found in a different conformation. Moreover, one finds that some solvents that show partial immiscibility with the polymer strongly alter the formation of the film. The observations made for the two different types of polymers allow for an assignment of film‐formation driving forces to individual polymer segments and allow for the formulation of a growth model that explains the observed results and indicates the importance of appropriate substrate selection for organic electronic/optoelectronic devices.
Soft Lithography of Ceramic Patterns
Authors: Göbel O. F. , Nedelcu M. , Steiner U. 
Published: March 2007

AbstractPolymer‐based precursor solutions are patterned using a soft‐lithographic patterning technique to yield sub‐micrometer‐sized ceramic patterns. By using a polymer–metal‐nitrate solution as a lithographic resist, we demonstrate a micromolding procedure using a simple rubber stamp that yields a patterned precursor layer. A subsequent high‐temperature annealing step degrades the polymer giving rise to a patterned metal oxide film. This procedure is demonstrated for three different ceramic materials: Al2O3, ZnO, and PbTiO3. Al2O3 initially forms an amorphous phase that is subsequently converted into a polycrystalline material upon electron irradiation. The formed ZnO and PbTiO3 are polycrystalline. PbTiO3 exhibits epitaxial alignment when cast onto a SrTiO3(001) surface that matches its lattice periodicity. This epitaxial alignment is maintained when the PbTiO3 phase is patterned by micromolding, giving rise to epitaxially grown PbTiO3 patterns with feature sizes down to 300 nm.
Dysregulation of X‐linked gene expression in Klinefelter's syndrome and association with verbal cognition
Authors: Vawter Marquis P. , Harvey Philip D. , DeLisi Lynn E. 
Published: March 2007

AbstractKlinefelter's Syndrome (KS) is a chromosomal karyotype with one or more extra X chromosomes. KS individuals often show language impairment and the phenotype might be due to overexpression of genes on the extra X chromosome(s). We profiled mRNA derived from lymphoblastoid cell lines from males with documented KS and control males using the Affymetrix U133P microarray platform. There were 129 differentially expressed genes (DEGs) in KS group compared with controls after Benjamini–Hochberg false discovery adjustment. The DEGs included 14 X chromosome genes which were significantly over‐represented. The Y chromosome had zero DEGs. In exploratory analysis of gene expression–cognition relationships, 12 DEGs showed significant correlation of expression with measures of verbal cognition in KS. Overexpression of one pseudoautosomal gene, GTPBP6 (GTP binding protein 6, putative) was inversely correlated with verbal IQ (r = −0.86, P < 0.001) and four other measures of verbal ability. Overexpression of XIST was found in KS compared to XY controls suggesting that silencing of many genes on the X chromosome might occur in KS similar to XX females. The microarray findings for eight DEGs were validated by quantitative PCR. The 14 X chromosome DEGs were not differentially expressed in prior studies comparing female and male brains suggesting a dysregulation profile unique to KS. Examination of X‐linked DEGs, such as GTPBP6, TAF9L, and CXORF21, that show verbal cognition–gene expression correlations may establish a causal link between these genes, neurodevelopment, and language function. A screen of candidate genes may serve as biomarkers of KS for early diagnosis. © 2007 Wiley‐Liss, Inc.
Facile exfoliation of rectorite nanoplatelets in soy protein matrix and reinforced bionanocomposites thereof
Authors: Yu Jiahui , Cui Guojuan , Wei Ming , Huang Jin 
Published: March 2007

AbstractThe rectorite (REC), a form of layered silicate, was facilely intercalated and even exfoliated in soy protein isolate (SPI) matrix. Furthermore, the reinforced biodegradable nanocomposite sheets were produced, in which the exfoliated REC lamellae plays a key role. After solution‐mixing, XRD patterns showed that the REC lamellae were intercalated and even completely exfoliated for 4 wt % REC added, but the expanded gallery gradually became narrower with increasing REC content. FT‐IR also verified the molecular‐level associations between SPI molecules and REC lamellae by vibration variances of hydrogen bonding. The compression‐molding further promoted intercalation and exfoliation, namely the 8 wt % REC can also be almost dispersed as exfoliated lamellae, while the interlayer of RECs also further separated for nanocomposites with higher REC content. TEM images visualized the transfer from exfoliation to intercalation and the decrease of interlayer distance with increasing REC content. The thicker and longer exfoliated REC lamellae resulted in high load and easy‐to‐yield of material. The maximum strength of nanocomposite sheets occurred at the addition of 12 wt % REC. Thereafter, the SPI chain can move more easily because of weak interaction between free negative‐charge rich domain of SPI and REC surface in gallery, which did not favor enhancing mechanical performance. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Construction of a choline biosensor through enzyme immobilization on a poly(2‐hydroxyethyl methacrylate)‐grafted Teflon film
Authors: Yucel Deniz , Ozer Nazmi , Hasirci Vasif 
Published: March 2007

AbstractAn amperometric choline biosensor was constructed by immobilizing choline oxidase (ChO) on poly(2‐hydroxyethyl methacrylate) (PHEMA)‐grafted Teflon (polytetrafluoroethylene, PTFE) film. Grafting was achieved by γ irradiation. PHEMA‐grafted Teflon films were activated with epichlorohydrin or glutaraldehyde to achieve covalent immobilization of enzyme onto the film. To decrease the diffusional barrier caused by the enzyme‐immobilized film, the film was stretched directly on the electrode. The PHEMA‐grafted Teflon film, therefore, had to have appropriate mechanical properties. Glucose oxidase (GOD) was used in the determination of optimum immobilization conditions, then these were applied to ChO. With GOD, the effect of activation type and film position in electrode on enzyme activity was studied and the highest catalytic activity was obtained when the enzyme was immobilized using glutaraldehyde and the film was stretched over the electrode surface. Further studies revealed that the films activated with glutaraldehyde, immobilized in 2 mg/mL ChO concentration, and stretched directly on the electrode were suitable (specific activity, 0.427 ± 0.068 U mg−1) for use in the choline biosensor. The linear working range of this biosensor was found to be 52–348 μM, with a 40 ± 5 μM minimum detection limit. The response of the sensor, however, decreased linearly upon repeated use. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Melting, crystallization behaviors, and nonisothermal crystallization kinetics of PET/PTT/PBT ternary blends
Authors: Run Mingtao , Song Aijun , Wang Yingjin , Yao Chenguang 
Published: March 2007

AbstractThe melting, crystallization behaviors, and nonisothermal crystallization kinetics of the ternary blends composed of poly(ethylene terephthalate), poly(trimethylene terephthalate) (PTT) and poly(buthylene terephthalate) (PBT) were studied with differential scanning calorimeter (DSC). PBT content in all ternary blends was settled invariably to be one‐third, which improved the melt‐crystallization temperature of the ternary blends. All of the blend compositions in amorphous state were miscible as evidenced by a single, composition‐dependent glass transition temperature (Tg) observed in DSC curves. DSC melting thermograms of different blends showed different multiple melting and crystallization peaks because of their various polymer contents. During melt‐crystallization process, three components in blends crystallized simultaneously to form mixed crystals or separated crystals depending upon their content ratio. The Avrami equation modified by Jeziorny and the Ozawa theory were employed to describe the nonisothermal crystallization process of two selected ternary blends. The results spoke that the Avrami equation was successful in describing the nonisothermal crystallization process of the ternary blends. The values of the t1/2 and the parameters Zc showed that the crystallization rate of the ternary blends with more poly(ethylene terephthalate) content was faster than that with the lesser one at a given cooling rate. The crystal morphology of the five ternary blends investigated by polarized optical microscopy (POM) showed different size and distortional Maltese crosses or light spots when the PTT or poly(ethylene terephthalate) component varied, suggesting that the more the PTT content, the larger crystallites formed in ternary blends. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Electrorheological properties of kaolinite, polyindole, and polyindole/kaolinite composite suspensions
Authors: Arslan Yasin , Ibrahim Unal Halil , Yilmaz Hasim , Sari Bekir 
Published: March 2007

AbstractIn this study, polyindole (PIN) and polyindole/kaolinite (PIN/KAO) composite were synthesized by free radical polymerization using FeCl3 as an initiator. Average particle sizes (d50) of PIN and PIN/KAO composite were determined by dynamic light scattering (DLS) as 7.2 and 6.2 μm, respectively. The samples were characterized by FTIR, elemental analysis, DSC/TGA and SEM measurements. Suspensions of KAO, PIN, and PIN/KAO composite were prepared in silicone oil (SO) and the sedimentation stabilities were determined. Electrorheological (ER) properties of these suspensions were studied as a function of dispersed phase concentration, shear rate, shear stress, and temperature; and yield stresses and excess shear stresses determined. Further, dielectric properties of KAO, PIN, and PIN/KAO composite were investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Haptoglobin‐stimulated bone resorption in neonatal mouse calvarial bones in vitro
Authors: Lerner Ulf H. , Fröhlander Nils 
Published: March 2007

AbstractObjective. To study the in vitro effects of human haptoglobin (Hp) on bone resorption and prostanoid formation.Methods. Parietal bones were dissected out from neonatal mice that had been injected with 45Ca, and were cultured in chemically defined medium with or without test substances. Bone resorption was assessed by analysis of 45Ca release. Prostanoid formation was quantified by analysis of the amount of prostaglandin E2 (PGE2) in culture medium.Results. Hp phenotype 2–1, in quantities ≥0.17 mg/ml, stimulated the release of 45Ca and the biosynthesis of PGE2, in a time‐ and dose‐dependent manner. Hp‐induced PGE2 formation was abolished by indomethacin and flurbiprofen, whereas the stimulation of 45Ca release was only partially reduced.Conclusion. These observations suggest that the acute‐phase reactant Hp may contribute, by a humoral mechanism, to the bone resorption seen in chronic inflammatory processes.
The news of science, a colloquium‐style course designed to promote lifelong scientific awareness
Authors: Mathews Christopher K. 
Published: March 2007

AbstractIt is generally agreed that informed citizens in a republic such as the United States should maintain broad awareness of current developments in science and technology. This paper describes a colloquium‐style course, The News of Science, designed to stimulate in undergraduate students a desire for such awareness, and to present a convenient means for doing so. The course, which has been offered since 2000 at Oregon State University, requires students to read Science magazine and to present oral reports on articles of their choosing. Each student in the course is required to read all of the articles selected for oral presentation, and to contribute toward discussion of each talk.
HPLC determination of caffeine and paraxanthine in urine: An assay for cytochrome P450 1A2 activity
Authors: Furge Laura Lowe , Fletke Kyle J. 
Published: March 2007

AbstractCytochrome P450 enzymes are a family of heme‐containing proteins located throughout the body with roles in metabolism of endogenous and exogenous compounds. Among exogenous compounds, clinically relevant pharmaceutical agents are nearly all metabolized by P450 enzymes. However, the activity of the different cytochrome P450 enzymes varies among individuals and, therefore, so does drug efficacy as well as susceptibility to side effects and toxicity. Thus, assessing P450 activity is of great interest in drug development and clinical pharmacology. This study investigates the phenotyping of a single P450 activity by analyzing urine samples using isocratic reverse‐phase HPLC. Specifically, the activity of human P450 1A2, which converts caffeine into paraxanthine, can be investigated by measuring the change in caffeine and paraxanthine concentrations in urine over time following a single dose of caffeine. There is an observable relationship between caffeine intake and paraxanthine formation that varies among individuals. This laboratory exercise provides a means for simple assessment of P450 1A2 metabolic activity using an HPLC method without additional extraction or purification steps and introduces students to the complexities of individualized medicine as well as the basic biochemical techniques of sample preparation and quantitative HPLC. Furthermore, students may design and test their own hypothesis using these methods.
Reversible ligand binding reactions: Why do biochemistry students have trouble connecting the dots?
Authors: Sears Duane W. , Thompson Scott E. , Saxon S. Robin 
Published: March 2007

AbstractAdaptive chemical behavior is essential for an organism's function and survival, and it is no surprise that biological systems are capable of responding both rapidly and selectively to chemical changes in the environment. To elucidate an organism's biochemistry, its chemical reactions need to be characterized in ways that reflect the normal physiology in vivo. This is a challenging experimental problem because biological systems are inherently complex with myriads of interlinked chemical networks orchestrating processes that are mostly irreversible in nature. One successful approach for simplifying the study of biochemical reactions is to analyze them under controlled reversible equilibrium conditions in vitro that approximate the range of physiological conditions found in vivo. Because this approach has helped elucidate some of the chemical mysteries of complex biological systems, many topics presented in modern biochemistry courses are essentially rooted in the chemistry of reversible equilibrium reactions. Since most undergraduate biochemistry courses typically require students to complete year‐long general and organic chemistry courses, biochemistry instructors may assume that entering students have sufficient understanding of basic reversible equilibrium chemistry to move forward into more advanced biochemical topics. However, this assumption is at odds with our experience in that many entering students seem confused by the conventions, language, symbolic formalism, and/or mathematical tools normally use to describe reversible equilibrium reactions. Part of the problem here may stem from how certain basic chemical concepts are taught (or are not taught) in their prerequisite chemistry courses. Here, we identify some conceptual barriers that many students seem to confront and we discuss instructional strategies designed to help students “connect the dots,” so to speak, and better understand how dynamic biological processes can be analyzed in terms of reversible equilibrium chemistry.