bluuebunny/crossref_metadata_2025_split huggingface dataset:
Toward localizing genes underlying cerebral asymmetry and mental health
Authors: Smalley Susan L. , Loo Sandra K. , Yang May H. , Cantor Rita M. 
Published: April 2005

AbstractGenome investigations of autism, attention deficit hyperactivity disorder (ADHD), and dyslexia suggest possible genetic overlap. Atypical cerebral asymmetry (ACA), the absence of the left hemisphere dominance for language, may be a shared phenotype due to genes located in regions of overlap. A binomal test is used to evaluate whether linked regions overlap more than expected by chance for 15 genome‐wide scans in autism, ADHD, and dyslexia. Significant evidence of linkage overlap (P = 10−7) is seen for autism, ADHD, and dyslexia for seven chromosomal regions (2p11–12, 5p13, 7q22–33, 9q33–34, 13q22, 16p13, and 17p11–q11). Linkage analysis of ACA and molecular markers for 270 sibling pairs with ADHD is conducted using the Haseman–Elston statistic. Linkage analysis supports ACA as a shared phenotype with risk genes located on 9q33–34 or 16p13 (P < 0.004). Further support stems from the overlap of these regions in schizophrenia, bipolar illness, specific language impairment (SLI), and handedness, all traits associated with ACA. Autism, ADHD, and dyslexia share regions of linkage overlap and ACA may be a shared phenotype for such genes similar to HLA in autoimmune disease. Because ACA is associated with certain aspects of creativity, such risk genes may also be enhancer genes for creativity. © 2005 Wiley‐Liss, Inc.
Vesicular glutamate transporter‐1 colocalizes with endogenous opioid peptides in axon terminals of the rat locus coeruleus
Authors: Barr Jeffrey , Van Bockstaele Elisabeth J. 
Published: April 2005

AbstractWe have previously shown that a subset of axon terminals in the locus coeruleus (LC) containing methionine5‐enkephalin (ENK) forms type I (asymmetric‐type) synaptic specializations that are characteristic of excitatory‐type transmitters. In addition, we previously provided ultrastructural evidence showing that ENK is colocalized with glutamate using a combination of pre‐ and postembedding immunohistochemistry. To examine cellular substrates for interactions between glutamate and other endogenous opioid peptides in the LC, we examined the localization of the vesicular glutamate transporter 1 (VGLUT1), a transporter protein involved in the accumulation of the transmitter glutamate into synaptic vesicles, with either ENK or preprodynorphin (ppDYN). Dual‐immunofluorescence and electron microscopy showed prominent coexistence of VGLUT1 and ENK in varicose processes of the LC, confirming our previous report using postembedding immunolabeling for glutamate. Likewise, VGLUT1 and ppDYN were identified in common varicose processes in the LC using confocal fluorescence microscopy. Immunoelectron microscopy using gold‐silver labeling for VGLUT1 and peroxidase labeling for ppDYN established that this endogenous opioid peptide also colocalizes with glutamate transporters. The majority of these formed asymmetric‐type synapses. Taken together, these results demonstrate that excitatory LC afferents are enriched with endogenous opioid peptides and are positioned to modulate LC neuronal activity dually. © 2005 Wiley‐Liss, Inc.
Embryonic cerebrospinal fluid regulates neuroepithelial survival, proliferation, and neurogenesis in chick embryos
Authors: Gato Ángel , Moro J.A. , Alonso M.I. , Bueno D. , De La Mano A. , Martín C. 
Published: April 2005

AbstractEarly in development, the behavior of neuroepithelial cells is controlled by several factors, which act in a developmentally regulated manner. Diffusible factors are secreted locally by the neuroepithelium itself, although other nearby structures may also be involved. Evidence suggests a physiological role for the cerebrospinal fluid in the development of the brain. Here, using organotypic cultures of chick embryo neuroepithelial explants from the mesencephalon, we show that the neuroepithelium in vitro is not able to self‐induce cell survival, replication, and neurogenesis. We also show that the embryonic cerebrospinal fluid (E‐CSF) promotes neuroepithelial stem cell survival and induces proliferation and neurogenesis in mesencephalic explants. These data strongly suggest that E‐CSF is involved in the regulation of neuroepithelial cells behavior, supporting the hypothesis that this fluid plays a key role during the early development of the central nervous system. © 2005 Wiley‐Liss, Inc.
Arterial embolization using poly‐N‐acetyl glucosamine gel in a rat kidney model
Authors: Kang Qian K. , An Yuehuei H. , Moreira Patricia L. , Demcheva Marina V. , Vournakis John N. 
Published: April 2005

AbstractAqueous solutions of poly‐N‐acetyl glucosamine (p‐GlcNAc) exhibit a liquid‐gel transition at physiological pH and temperature. This feature inspired the authors to conduct a study to evaluate the macro‐ and histological changes of rat kidneys after embolization using either p‐GlcNAc gel injection into the renal artery or ligation of the renal artery. The procedures were performed in 46 rats through open abdominal surgeries. Animals were sacrificed at 3 days and at 1, 3, 5, and 8 weeks postoperatively. The results of both macro‐observation and histological study showed that p‐GlcNAc gels were effective in causing necrosis and subsequent fibrosis in all embolized kidneys. The data indicate that p‐GlcNAc gel may have promise as an effective agent for therapeutic embolization. © 2005 Wiley‐Liss, Inc.
Community networks: Community capital or merely an affordable Internet access tool?
Authors: Kwon Nahyun 
Published: April 2005

AbstractIn this study a perceived gap between the ideal and the reality of a community network (CN) is examined. Most proponents of CNs state that building a better physical community is their major service goal. However, there has been a concern that citizens might use the service simply as a means to connect to the Internet rather than as a means to connect to their communities. Using a survey research method (n = 213), users' perceptions of community aspects of CN service and the influence of such perceptions on their use were investigated. User demographics and alternative service accessibility were also examined as predictors of use. The present study found that the respondents were using the service mainly for general Internet features. More than two thirds of the respondents were not aware of the community content aspect of the service. Approximately 20% of respondents were identified as those whose perceptions of the community aspects actually affected their use of the service. They were both aware of community contents and using an additional Internet service provider. Findings suggest that the providers did not fully communicate the community aspects of the service with the users, while the user perception of community aspects is a key to further promotion of the service.
Testing user interaction with a prototype visualization‐based information retrieval system
Authors: Koshman Sherry 
Published: April 2005

AbstractThe VIBE (Visual Information Browsing Environment) prototype system, which was developed at Molde College in Norway in conjunction with researchers at the University of Pittsburgh, allows users to evaluate documents from a retrieved set that is graphically represented as geometric icons within one screen display. While the formal modeling behind VIBE and other information visualization retrieval systems is well known, user interaction with the system is not. This investigation tested the designer assumption that VIBE is a tool for a smart (expert) user and asked: What are the effects of the different levels of user expertise upon VIBE usability? Three user groups including novices, online searching experts, and VIBE system experts totaling 31 participants were tested over two sessions with VIBE. Participants selected appropriate features to complete tasks, but did not always solve the tasks correctly. Task timings improved over repeated use with VIBE and the nontypical visually oriented tasks were resolved more successfully than others. Statistically significant differences were not found among all parameters examined between novices and online experts. The VIBE system experts provided the predicted baseline for this study and the VIBE designer assumption was shown to be correct. The study's results point toward further exploration of cognitive preattentive processing, which may help to understand better the novice/expert paradigm when testing a visualized interface design for information retrieval.
Growth characteristics of Arthrospira platensis cultured inside a new close‐coil photobioreactor incorporating a mandrel to control culture temperature
Authors: Carlozzi Pietro , Pinzani Edoardo 
Published: April 2005

AbstractThe aim of this study was to investigate Arthrospira growth inside a new CCP incorporating a mandrel for culture temperature control. Some hydrodynamic aspects and photobioreactor performances were investigated as well. The bioreactor incorporated A. platensis grown under batch and semicontinuous conditions. Two systems were used to recycle Arthrospira cultures: a peristaltic pump and an airlift system. When the pump recycled the culture, we achieved a very high Dean number (De = 3,950), which decreased a great deal when the pump was replaced with the airlift system. During outdoor Arthrospira batch growth, a cell concentration of 16.4 g (DW)l−1 was reached after 9 days. However, the maximum chlorophyll content of the biomass (2.0% of DW) was achieved on the fifth and sixth days. The highest daily biomass output rate was obtained using the airlift system, when the CCP was operated under a semicontinuous regime: the gross output rate was 2.85 ± 0.37 g (DW) l−1 d−1 and the net was 2.32 ± 0.11 g (DW) l−1 d−1. The advantages of the airlift system may be due to the low concentration of oxygen built up inside Arthrospira culture and the lack of cell damage due to the pump system. Thus, oxygen and pump stress may have been avoided. © 2005 Wiley Periodicals, Inc.
Immobilized N‐alkylated polyethylenimine avidly kills bacteria by rupturing cell membranes with no resistance developed
Authors: Milović Nebojša M. , Wang Jun , Lewis Kim , Klibanov Alexander M. 
Published: April 2005

AbstractSeveral critical mechanistic and phenomenological aspects of the microbicidal surface coatings based on immobilized hydrophobic polycations, previously developed by us, are addressed. Using Escherichia coli (Gram‐negative) and Staphylococcus aureus (Gram‐positive) bacteria, remarkable bactericidal action (up to a 109‐fold reduction in live bacteria count in the surface‐exposed solution and a 100% inactivation of the surface‐adhered bacteria) of an amino‐glass slide covalently derivatized with N‐hexyl,methyl‐polyethylenimine (PEI) is found to be due to rupturing bacterial cell membranes by the polymeric chains. The bacteria fail to develop noticeable resistance to this lethal action over the course of many successive generations. Finally, the immobilized N‐alkyl‐PEI, while deadly to bacteria, is determined to be harmless to mammalian (monkey kidney) cells. © 2005 Wiley Periodicals, Inc.
Fed‐batch culture of a metabolically engineered Escherichia coli strain designed for high‐level succinate production and yield under aerobic conditions
Authors: Lin Henry , Bennett George N. , San Ka‐Yiu 
Published: April 2005

AbstractAn aerobic succinate production system developed by Lin et al. (Metab Eng, in press) is capable of achieving the maximum theoretical succinate yield of 1.0 mol/mol glucose for aerobic conditions. It also exhibits high succinate productivity. This succinate production system is a mutant E. coli strain with five pathways inactivated: ΔsdhAB, Δ(ackA‐pta), ΔpoxB, ΔiclR, and ΔptsG. The mutant strain also overexpresses Sorghum vulgare pepc. This mutant strain is designated HL27659k(pKK313). Fed‐batch reactor experiments were performed for the strain HL27659k(pKK313) under aerobic conditions to determine and demonstrate its capacity for high‐level succinate production. Results showed that it could produce 58.3 g/l of succinate in 59 h under complete aerobic conditions. Throughout the entire fermentation the average succinate yield was 0.94 ± 0.07 mol/mol glucose, the average productivity was 1.08 ± 0.06 g/l‐h, and the average specific productivity was 89.77 ± 3.40 mg/g‐h. Strain HL27659k (pKK313) is, thus, capable of large‐scale succinate production under aerobic conditions. The results also showed that the aerobic succinate production system using the designed strain HL27659k(pKK313) is more practical than conventional anaerobic succinate production systems. It has remarkable potential for industrial‐scale succinate production and process optimization. © 2005 Wiley Periodicals, Inc.
Quantitative determination of alkylated quaternary amines and their n‐hydroxylated metabolites in an enzyme incubation matrix by liquid chromatography electrospray ionization mass spectrometry
Authors: Holmes Victoria E. , Shaw P. Nicholas , Ortori Catharine A. , Barrett David A. 
Published: April 2005

AbstractA simple, rapid and sensitive reversed‐phase liquid chromatography method coupled to electrospray ionization mass spectrometry has been developed for studying the in vitro metabolism of the long‐chain quaternary ammonium compounds dodecyltrimethylamine, tetradecyltrimethylamine and hexadecyltrimethylamine. Samples were prepared from the biological matrix by a simple protein precipitation stage. The separation was performed using a BDS Hypersil C8 3 µm particle size (100 × 3 mm i.d.) column with a fast gradient separation (60% B to 100% B) using a mobile phase of 10 mm aqueous ammonium acetate (pH 4.0, with 0.06% triethylamine; (A)–acetonitrile (B) at 0.7 mL min−1. To minimize contamination of the MS source a switching value was used to divert the solvent front to waste. Decylammonium bromide was used as the internal standard and analytes were identified and quantified by positive ion electrospray selected ion monitoring of their intact molecular cations. The assay had a limit of quantitation of 0.25 µm (6.25 pmol on column) and was linear over the range 0.25–100 µm assay concentration for this series of long‐chain quaternary amines. The precision of intra‐ and inter‐day assays was better than 19% and the accuracy was between 93 and 109%. The method was used to assess the in vitro metabolism of the quaternary amines by wild‐type cytochrome P450 enzyme CYP4A1 and mutants in an artifical membrane system. Copyright © 2005 John Wiley & Sons, Ltd.
The effects of ligand chain length, salt concentration and temperature on the adsorption of bovine serum albumin onto polypropyleneglycol–Sepharose
Authors: Dias‐Cabral A. C. , Ferreira A. S. , Phillips J. , Queiroz J. A. , Pinto N. G. 
Published: April 2005

AbstractThe interaction thermodynamics associated with bovine serum albumin adsorption on polypropylene glycol (n = 3)–Sepharose CL‐6B and polypropylene glycol (n = 7)–Sepharose CL‐6B, using ammonium sulfate as the modulator was studied. Analysis of data under linear conditions was accomplished with the stoichiometric displacement retention model, preferential interaction approach and van't Hoff plots applied to HIC systems. Preferential interaction analysis indicated a strong entropic driving force under linear conditions, due to the release of a large amount of solvent on adsorption. In contrast, flow microcalorimetry under overloaded conditions showed that the adsorption of bovine serum albumin may be entropically or enthalpically driven. It is postulated that adsorption in the nonlinear region is influenced by the degree of water release, protein–protein interactions on the surface, reorientation of ligand, and conformational changes in the protein. Copyright © 2005 John Wiley & sons, Ltd.
Coherent Control for Spectroscopy and Manipulation of Biological Dynamics
Authors: Wohlleben Wendel , Buckup Tiago , Herek Jennifer L. , Motzkus Marcus 
Published: April 2005

AbstractMotivated originally by the goal of steering a photoreaction into desired product channels, the concept of coherent control is to adapt the spectral and temporal characteristics of the excitation light to the inherent molecular resonances and dynamics, such that these can be selectively addressed and manipulated. In the last decade, the ultrafast dynamics of many atomic and molecular quantum systems in the gas and condensed phase have been controlled successfully. Motivations in chemistry are now 1) to perform spectroscopy by coherent control, which requires a deeper understanding of control mechanisms, 2) to treat more complex, biological photoreactions, and 3) the pragmatic use of coherent control techniques, for example, for pulse compression or enhanced contrast in multiphoton microscopy. As examples for 1) and 2) we review here the combined effort and interplay of conventional spectroscopy and coherent control experiments, applied to the energy flow in the light‐harvesting complex LH2 from bacterial photosynthesis. Closed‐loop control experiments allowed the characteristic coupling frequency of internal conversion in the carotenoid in LH2 to be extracted. Open‐loop three‐pulse control experiments, on the other hand, could directly observe an anticipated Raman‐excited carotenoid ground state. As a variant of difference spectroscopy, coherent control has thus served to gain complementary spectroscopic knowledge about the energy flow in carotenoids by comparing natural to manipulated dynamics. Finally, we propose future coherent control experiments on the electronic state structure of carotenoids and discuss prospects of coherent control for other biological chromophores.
Theoretical Study of Inversion and Topomerization Processes of Substituted Cyclohexanes: The Relevance of the Energy 3D Hypersurface
Authors: Fernández‐Alonso María del Carmen , Cañada Javier , Jiménez‐Barbero Jesús , Cuevas Gabriel 
Published: April 2005

AbstractAlthough the potential energy surface of highly symmetric cyclohexane has been extensively reviewed, no attention has been paid to the study of the effect of substitution of a methylene group by a heteroatom. The substitution may cause changes in molecular symmetry as well as the dipole moment, and the unshared electron pairs associated with the heteroatom may also introduce changes in molecular reactivity. However, these phenomena are not yet completely understood. To address these issues, a rigorous description of the inversion–topomerization process of methylcyclohexane and a revision of the conformational potential energy of oxane and thiane are presented. Moreover, the usefulness of providing a three‐dimensional representation of these processes is discussed. In the case of methylcyclohexane, calculations show that three transition states are associated with inversion and four more with topomerization. In contrast, for oxane and thiane, only two transition states are involved with inversion and two with topomerization.Two fundamental conclusions can be drawn from this study. The first is that the inversion process occurs through elementary stages that we have denoted “conformational elemental stages”, which is an analogous term to that used for reaction mechanism description (minima–transition state–minima) where several elemental steps take place. The second conclusion is that two independent processes, inversion and topomerization, are connected by some common conformers. The inversion process controls the ring interchange, while topomerization allows exchange between skewed boats.
Single‐Molecule Quantum‐Dot Fluorescence Resonance Energy Transfer
Authors: Hohng Sungchul , Ha Taekjip 
Published: April 2005

AbstractColloidal semiconductor quantum dots are promising for single‐molecule biological imaging due to their outstanding brightness and photostability. As a proof of concept for single‐molecule fluorescence resonance energy transfer (FRET) applications, we measured FRET between a single quantum dot and a single organic fluorophore Cy5. DNA Holliday junction dynamics measured with the quantum dot/Cy5 pair are identical to those obtained with the conventional Cy3/Cy5 pair, that is, conformational changes of individual molecules can be observed by using the quantum dot as the donor.
Thermomechanics of the shape memory effect in polymers for biomedical applications
Authors: Gall Ken , Yakacki Christopher M. , Liu Yiping , Shandas Robin , Willett Nick , Anseth Kristi S. 
Published: April 2005

AbstractWe examine the shape memory effect in polymer networks intended for biomedical, and specifically cardiovascular, applications. The polymers were synthesized by photopolymerization from a tert‐butyl acrylate monomer with a diethyleneglycol diacrylate crosslinker. Three‐point flexural tests were used to systematically investigate the thermomechanics of shape storage (predeformation) and shape recovery. The glass transition temperature, Tg, of the polymers was determined to be approximately 65°C. The polymers show 100% strain recovery, at low and high predeformation temperatures, up to maximum strains of ∼80%. The polymers show a sigmoidal free strain recovery response as a function of increasing temperature at a constant heating rate. Free strain recovery was determined to depend on the temperature during predeformation; lower predeformation temperatures (T < Tg) decreased the temperature required for free strain recovery. Constrained stress recovery shows a complex evolution as a function of temperature and also depends on the temperature during predeformation. Stress recovery after low‐temperature predeformation (T < Tg) shows a peak in the generated recovery stress, whereas stress recovery after high‐temperature predeformation (T > Tg) is sigmoidal. The isothermal free strain recovery rate was found to increase with increasing temperature or decreasing predeformation temperature. The thermomechanical results are discussed in light of potential biomedical applications, and a prototype device is presented. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res 73A: 339–348, 2005