bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Characterization of Magnesium‐Aluminum Layered Double Hydroxides Containing (Tetrasulfonated porphyrin)cobalt
Authors: Barbosa César A. S. , Ferreira Ana Maria D. C. , Constantino Vera R. L. 
Published: April 2005

AbstractWe report the synthesis and characterization of a magnesium‐aluminum layered double hydroxide (LDH) containing[5,10,15,20‐tetrakis(4‐sulfonatophenyl)porphyrinato]cobalt(II)(CoTPhsP) by two routes: (i) CoTPhsP intercalation by structure reconstruction of the calcined pristine LDH [Mg2.8Al(CoTPhsP)int] and (ii) adsorption of the CoTPhsP on the external surfaces of the noncalcined pristine LDH [Mg3.0Al(CoTPhsP)ads]. The intercalation and adsorption of CoTPhsP in the LDHs were evaluated using different techniques, such as X‐ray diffraction, thermogravimetry, scanning electronic microscopy, and surface area and porosity analysis. Further characterization by electron spin resonance and UV/Vis spectroscopy showed that the CoTPhsP molecules adsorbed and intercalated in the LDHs are present as two predominant species: the complex formed with molecular oxygen (CoTPhsP–O2) and the corresponding deoxy monomeric species (CoTPhsP). The stability and reactivity of the CoTPhsP immobilized in the LDHs were evaluated in the presence of hydrogen peroxide solution. CoTPhsP in homogeneous conditions is deactivated by molecular aggregation and/or oxidative self‐destruction in the presence of H2O2. On the other hand, CoTPhsP stability and reactivity were improved when adsorbed and intercalated in the LDHs. Mg3.0Al(CoTPhsP)ads is more active than Mg2.8Al(CoTPhsP)int in the decomposition of hydrogen peroxide to H2O and O2. A porosity analysis carried out by N2 adsorption‐desorption experiments for the intercalated material exhibited a type‐IV isotherm characteristic of nonmicroporous materials. Hence, the CoTPhsP molecules located in the LDH galleries are not acessible to the H2O2, while the metal centers in the Mg3.0Al(CoTPhsP)ads sample are more available, which may explain the enhanced reactivity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Chiral Indenes and Group‐4 Metallocene Dichlorides Containing α‐ and β‐Pinenyl‐Derived Ligand Substituents: Synthesis and Catalytic Applications in Polymerization and Carboalumination Reactions
Authors: Silver Satu , Puranen Arto , Sjöholm Rainer , Repo Timo , Leino Reko 
Published: April 2005

AbstractThe synthesis and characterization of chiral bis(indenyl)zirconium dichlorides containing β‐pinenyl‐derived ligand substituents is reported. Unbridged metallocene complexeshaving the {[(1S,2S,5S)‐6,6‐dimethylbicyclo[3.1.1]hept‐2‐yl]methyl}dimethylsilyl substituent in both 1‐ and 2‐positions of the indenyl moiety were prepared and isolated in moderate to low yields by reaction of the corresponding indenyllithium salts with ZrCl4 followed by work‐up and crystallization procedures. The corresponding tetrahydroindenyl complexes were obtained in excellent yields by catalytic hydrogenation of the indenyl six‐membered rings. In a complementary approach, a synthetic route to α‐pinenyl‐substituted indenyl ligand analogues was briefly evaluated, which however, suffered from low yields. Selected β‐pinenyl‐substituted indenyl complexes were scanned as catalysts for the dehydropolymerization of phenylsilane upon activation with nBuLi, for polymerization of ethylene and propylene upon activation with methylaluminoxane (MAO) as well as for enantioselective carboalumination of 1‐octene with triethyl‐ and trimethylaluminum. The bis(indenyl) complexes catalyzed the carboalumination reaction, albeit only low yields (8–16 %) and low enantioselectivities (ee = 0.5–10 %) were obtained. The 2‐substituted bis(indenyl)zirconocene/MAO catalyst system produced atactic low‐molecular weight polypropylene with low polymerization activity whereas both 1‐ and 2‐substituted complexes showed high activities in ethylene polymerization producing polyethylenes with high molecular weights (Mw > 440000). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
The First Sandwich‐Type Heteropolytungstates Consisting of Trivacant Gallium(III)‐Substituted Keggin Fragments
Authors: Drewes Daniel , Limanski Eva Melanie , Krebs Bernt 
Published: April 2005

AbstractThe new polyoxotungstates (NH4)5Na9[Cu4(H2O)2(GaW9O34)2]·22 H2O (1) and (NH4)14[Zn4(H2O)2(GaW9O34)2]·37 H2O (2) were synthesized in aqueous solution and characterized by IR and Raman spectroscopy, energy dispersive X‐ray fluorescence and single‐crystal X‐ray analysis. Compounds 1 and 2 contain the trivacant α‐B‐(GaW9O34)11– Keggin fragment, which is structurally characterized for the first time. The lacunary (GaW9O34)11– structure exhibits a centered GaIII atom, which is bound to four oxygen atoms and thus achieves a tetrahedral coordination sphere. The synthesis of 1–2 enlarges the class of sandwich‐type polyoxoanions and enables the syntheses of a new series of gallium(III)‐substituted polyoxotungstates. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Prevalence of five previously reported and recurrent BRCA1 genetic rearrangement mutations in 20,000 patients from hereditary breast/ovarian cancer families
Authors: Hendrickson Brant C. , Judkins Thaddeus , Ward Benjamin D. , Eliason Kristilyn , Deffenbaugh Amie E. , Burbidge Lynn Anne , Pyne Kristin , Leclair Benoît , Ward Brian E. , Scholl Thomas 
Published: April 2005

AbstractMany rearrangement mutations in the BRCA1 gene have been identified. It is becoming clear that some of these mutations are prevalent, and therefore their detection is necessary in order for clinical genetic tests to have high sensitivity. Published information on particular rearrangements is frequently limited to a single patient, small groups of patients, or patients of a particular ethnicity. The objectives of this work included characterizing the prevalence of five specific rearrangement mutations in a large North American patient population. A mutation‐specific multiplex PCR assay was used for determining the prevalence of five BRCA1 rearrangement mutations that previously had been reported to occur in unrelated patients. The mutation status of these rearrangements, which came from 20,712 patients at high risk for hereditary breast and/or ovarian cancers who had submitted specimens for clinical genetic testing, is presented. The results, obtained from 2,634 mutation carriers, showed a 6‐kb duplication of exon 13, identified in 53 patients (2.01%); a 26‐kb deletion encompassing exons 14–20, detected in seven patients (0.27%); a 510‐bp deletion of exon 22, detected in 5 patients (0.19%); and a 3.4‐kb deletion of exon 13, detected in one patient (0.04%). A previously reported 7.1‐kb deletion of exons 8–9 was not found. The high frequency of the exon 13 duplication makes it the fourth most prevalent mutation in these patients. These results provide an accurate picture of the prevalence of these mutations in hereditary breast/ovarian cancer patients undergoing genetic testing in North America. © 2005 Wiley‐Liss, Inc.
Alterations in metabolism and gap junction expression may determine the role of astrocytes as “good samaritans” or executioners
Authors: Farahani Reza , Pina‐Benabou Mara H. , Kyrozis Andreas , Siddiq Ayesha , Barradas Penha C. , Chiu Fung‐Chow , Cavalcante Leny A. , Lai James C.K. , Stanton Patric K. , Rozental Renato 
Published: April 2005

AbstractOur knowledge of astroglia and their physiological and pathophysiological role(s) in the central nervous system (CNS) has grown during the past decade, revealing a complex picture. It is becoming increasingly clear that glia play a significant role in the homeostasis and function of the CNS and that neurons should no longer be considered the only cell type that responds, both rapidly and slowly, to electrochemical activity. We discuss recent advances in the field with an emphasis on the impact of hypoxia and ischemia on astrocytic metabolism and the functional relationship between glucose metabolism and gap junctions in astrocytes. We also address the controversy over whether astrocytic gap junctions mediate protection or killing of neurons during or after hypoxic or ischemic insults. © 2005 Wiley‐Liss, Inc.
Automated quality assurance routines for fMRI data applied to a multicenter study
Authors: Stöcker Tony , Schneider Frank , Klein Martina , Habel Ute , Kellermann Thilo , Zilles Karl , Shah N. Jon 
Published: April 2005

AbstractStandard procedures to achieve quality assessment (QA) of functional magnetic resonance imaging (fMRI) data are of great importance. A standardized and fully automated procedure for QA is presented that allows for classification of data quality and the detection of artifacts by inspecting temporal variations. The application of the procedure on phantom measurements was used to check scanner and stimulation hardware performance. In vivo imaging data were checked efficiently for artifacts within the standard fMRI post‐processing procedure by realignment. Standardized and routinely carried out QA is essential for extensive data amounts as collected in fMRI, especially in multicenter studies. Furthermore, for the comparison of two different groups, it is important to ensure that data quality is approximately equal to avoid possible misinterpretations. This is shown by example, and criteria to quantify differences of data quality between two groups are defined. Hum Brain Mapp 25:237–246, 2005. © 2005 Wiley‐Liss, Inc.
Differential activity in left inferior frontal gyrus for pseudowords and real words: An event‐related fMRI study on auditory lexical decision
Authors: Xiao Zhuangwei , Zhang John X. , Wang Xiaoyi , Wu Renhua , Hu Xiaoping , Weng Xuchu , Tan Li Hai 
Published: April 2005

AbstractAfter Newman and Twieg ([2001]: Hum Brain Mapp 14:39–47) and others, we used a fast event‐related functional magnetic resonance imaging (fMRI) design and contrasted the lexical processing of pseudowords and real words. Participants carried out an auditory lexical decision task on a list of randomly intermixed real and pseudo Chinese two‐character (or two‐syllable) words. The pseudowords were constructed by recombining constituent characters of the real words to control for sublexical code properties. Processing of pseudowords and real words activated a highly comparable network of brain regions, including bilateral inferior frontal gyrus, superior, middle temporal gyrus, calcarine and lingual gyrus, and left supramarginal gyrus. Mirroring a behavioral lexical effect, left inferior frontal gyrus (IFG) was significantly more activated for pseudowords than for real words. This result disconfirms a popular view that this area plays a role in grapheme‐to‐phoneme conversion, as such a conversion process was unnecessary in our task with auditory stimulus presentation. An alternative view was supported that attributes increased activity in left IFG for pseudowords to general processes in decision making, specifically in making positive versus negative responses. Activation in left supramarginal gyrus was of a much larger volume for real words than for pseudowords, suggesting a role of this region in the representation of phonological or semantic information for two‐character Chinese words at the lexical level. Hum Brain Mapp 25:212–221, 2005. © 2005 Wiley‐Liss, Inc.
Brain activity associated with painfully hot stimuli applied to the upper limb: A meta‐analysis
Authors: Farrell Michael J. , Laird Angela R. , Egan Gary F. 
Published: April 2005

AbstractThe capacity of pain to alert against potential injury or focus attention on damaged tissue is enhanced by the intrinsically aversive nature of the experience. Finding methods to relieve pain will ultimately be facilitated by deeper understanding of the processes that contribute to the experience, and functional brain imaging has contributed substantially toward that end. An impressive body of literature has identified a distributed network of pain‐related activity in the brain that is subject to considerable modulation by different stimulus parameters, contextual factors, and clinical conditions. The fundamental substrates of the pain network are yet to be distilled from the highly variable results of studies published thus far. Qualitative reviews of the pain‐imaging literature have been contributory, but lack the greater surety of quantitative methods. We employ the activation likelihood estimation (ALE) meta‐analytic technique to establish the most consistent activations among studies reporting brain responses subsequent to the application of noxious heat. A network of pain‐related activity was replicated for stimuli to either upper limb that included two discernible regions of the mid‐anterior cingulate cortex, bilateral thalami, insula, and opercula cortices, posterior parietal cortex, premotor cortex, supplementary motor area, and cerebellum. The findings of the meta‐analysis resonate with other streams of information that continue to enhance our understanding of pain in the brain. The results also point toward new areas of research that may be fruitful for the exploration of central pain processing. Hum Brain Mapp 25:129–139, 2005. © 2005 Wiley‐Liss, Inc.
Insulin‐like growth factor‐I protects granule neurons from apoptosis and improves ataxia in weaver mice
Authors: Zhong Jin , Deng Jixian , Phan Jennifer , Dlouhy Stephen , Wu Huangbing , Yao Weiguo , Ye Ping , D'Ercole A. Joseph , Lee Wei‐Hua 
Published: April 2005

AbstractMost cerebellar granule neurons in weaver mice undergo premature apoptosis during the first 3 postnatal weeks, subsequently leading to severe ataxia. The death of these granule neurons appears to result from a point mutation in the GIRK2 gene, which encodes a G protein‐activated, inwardly rectifying K+ channel protein. Although the genetic defect was identified, the molecular mechanism by which the mutant K+ channel selectively attacks granule neurons in weaver mice is unclear. Before their demise, weaver granule neurons express abnormally high levels of insulin‐like growth factor (IGF) binding protein 5 (IGFBP5). IGF‐I is essential for the survival of cerebellar neurons during their differentiation. Because IGFBP5 has the capacity to block IGF‐I activity, we hypothesized that reduced IGF‐I availability resulting from excess IGFBP5 accelerates the apoptosis of weaver granule neurons. We found that, consistently with this hypothesis, exogenous IGF‐I partially protected cultured weaver granule neurons from apoptosis by activating Akt and decreasing caspase‐3 activity. To determine whether IGF‐I protects granule neurons in vivo, we cross‐bred weaver mice with transgenic mice that overexpress IGF‐I in the cerebellum. The cerebellar volume was increased in weaver mice carrying the IGF‐I transgene, predominantly because of an increased number of surviving granule neurons. The presence of the IGF‐I transgene resulted in improved muscle strength and a reduction in ataxia, indicating that the surviving granule neurons are functionally integrated into the cerebellar neuronal circuitry. These results confirm our previous suggestion that a lack of IGF‐I activity contributes to apoptosis of weaver granule neurons in vivo and supports IGF‐I's potential therapeutic use in neurodegenerative disease. © 2005 Wiley‐Liss, Inc.
Transcriptome analysis of frontal cortex in alcohol‐preferring and nonpreferring rats
Authors: Worst Travis J. , Tan John C. , Robertson Daniel J. , Freeman Willard M. , Hyytia Petri , Kiianmaa Kalervo , Vrana Kent E. 
Published: April 2005

AbstractAlthough it is widely accepted that alcohol abuse and alcoholism have a significant genetic component of risk, the identities of the genes themselves remain obscure. To illuminate such potential genetic contributions, DNA macroarrays were used to probe for differences in normative cortical gene expression between rat strains genetically selected for alcohol self‐administration preference, AA (Alko, alcohol) and P (Indiana, preferring), or avoidance, ANA (Alko, nonalcohol) and NP (Indiana, nonpreferring). Among 1,176 genes studied, six demonstrated confirmable, differential expression following comparison of ethanol‐naive AA and ANA rats. Specifically, the mRNA level for metabotropic glutamate receptor 3 (mGluR3) was down‐regulated in the AA vs. ANA lines. In contrast, calcium channel subunit α2δ1 (cacna2d1), vesicle‐associated membrane protein 2 (VAMP2), syntaxin 1 (both syntaxin 1a and 1b; STX1a and STX1b), and syntaxin binding protein (MUNC‐18) mRNAs were found to be increased in frontal cortex following comparison of AA with ANA animals. Bioinformatic analysis of these molecular targets showed that mGluR3 and cacna2d1 fall within chromosomal locations reported to be alcohol‐related by the Collaborative Study on the Genetics of Alcoholism (COGA) as well as quantitative trait loci (QTL) studies. To determine further whether these differences were strain specific, the above‐mentioned genes were compared in ethanol‐preferring (P) and ‐nonpreferring (NP) selected lines. VAMP2 was the only gene that displayed statistically different mRNA levels in a comparison of P and NP rats. In conclusion, the altered cortical gene expression illuminated here would have the effect of altering neurotransmitter release in AA rats (compared with ANA rats). Such alterations, however, might not be a universal characteristic of all animal models of alcohol abuse and will also require further investigation in post‐mortem human samples. © 2005 Wiley‐Liss, Inc.
Diffusion Kinetics at Liquid‐Glassy Polymer Interphases
Authors: Arzondo Luis , Tomba J. Pablo , Carella José M. , Pastor José M. 
Published: April 2005

AbstractSummary: We explored the diffusion mechanisms in a series of liquid/glassy polymer interphases. The diffusion experiments were performed in a unique way: the temperature range studied encompassed the glass transition temperature (Tg) of the glassy matrices. We observed that the diffusion behavior of the liquid polymer was remarkably continuous when passing through the matrix Tg, and that the diffusion modes at the liquid/glassy interphases were very similar to those observed in liquid/liquid polymer diffusion.Diffusion profiles of liquid PS in glassy PPO obtained by confocal Raman spectroscopy. The sample was held at 160 °C for the times indicated in the plot.magnified imageDiffusion profiles of liquid PS in glassy PPO obtained by confocal Raman spectroscopy. The sample was held at 160 °C for the times indicated in the plot.
Ring‐Opening Polymerization of ε‐Caprolactone by Poly(ethylene glycol) by an Activated Monomer Mechanism
Authors: Kim Moon Suk , Seo Kwang Su , Khang Gilson , Lee Hai Bang 
Published: April 2005

AbstractSummary: The polymerization of ε‐caprolactone (CL) in the presence of HCl · Et2O by an activated monomer mechanism was performed to synthesize diblock or triblock copolymers composed of poly(ethylene glycol) (PEG) and poly(ε‐caprolactone) (PCL). The obtained PCLs had molecular weights close to the theoretical values calculated from the CL to PEG molar ratios and exibited monomodal GPC curves. We successfully prepared PEG and PCL block copolymers by a metal‐free method.The non‐metal catalyzed living ring‐opening polymerisation of ε‐caprolactone by PEG.magnified imageThe non‐metal catalyzed living ring‐opening polymerisation of ε‐caprolactone by PEG.
Minimizing the cost of placing and sizing wavelength division multiplexing and optical crossconnect equipment in a telecommunications network
Authors: Melián Belén , Laguna Manuel , Moreno‐Pérez José A. 
Published: April 2005

AbstractCost reduction is a major concern when designing optical fiber networks. Multiwavelength optical devices are new technology for increasing the capacity of fiber networks while reducing costs, when compared to installing traditional (e.g., SONET) equipment and new fiber. In this article we discuss the development of a metaheuristic method that seeks to optimize the location of Wavelength Division Multiplexing (WDM) and Optical Crossconnect (OXC) equipment in fiber networks. The procedure combines ideas from the scatter search, tabu search, and multistart methodologies. Computational experiments with both real‐world and artificial data show the effectiveness of the proposed procedure. The experiments include a comparison with a permutation‐based approach and with lower bounds generated with CPLEX. © 2005 Wiley Periodicals, Inc. NETWORKS, Vol. 45(4), 199–209 2005
Swelling and electroresponsive characteristics of interpenetrating polymer network hydrogels
Authors: Yoon Seoung Gil , Kim In Young , Kim Sun I , Kim Seon Jeong 
Published: April 2005

AbstractElectroactive polymer gels composed of poly(diallyldimethylammonium chloride), poly(acrylic acid) and poly(vinyl alcohol) were prepared and their swelling properties characterized. The swelling behavior of the polymer gels was studied by immersion of the gels into deionized water at room temperature. The state of the water in the polymer gels was characterized using differential scanning calorimetry and the microstructure of the swollen gel in each sample was investigated using scanning electron microscopy. The samples' response to being stimulated in an applied electric field was also investigated. Copyright © 2005 Society of Chemical Industry
Microstructural Differences between Virgin and Recycled Lots of PBX 9502
Authors: Peterson Paul D. , Idar Deanne J. 
Published: April 2005

AbstractPBX 9502 is an insensitive high explosive formulated comprised of 95 wt% TATB and 5 wt% Kel‐F 800TM binder. Due to the relatively high cost of manufacturing TATB (triaminotrinitrobenzene), methods for reclaiming TATB from PBX 9502 machine cuttings were previously developed. Reclaimed PBX 9502 was mixed with ~ 50% virgin PBX 9502 to produce “recycled” lots of PBX 9502. Several studies have shown significant differences between the mechanical properties of virgin and recycled lots of PBX 9502, and postulated that the differences were related to various aspects of TATB particle size and distribution. The purpose of this study is to show that these differences in mechanical properties are related to differences in the distribution of TATB within the microstructure of PBX 9502. Ultimately, a better understanding of these properties may lead to selected formulation changes for future rebuilds, Lifetime Extension Programs (LEP) and/or candidate replacements to enhance engineering and physics performance.
A Pressurized Vessel Test to Measure the Minimum Burning Pressure of Water‐Based Explosives
Authors: Turcotte Richard , Lightfoot Phillip D. , Badeen Christopher M. , Vachon Marie , Jones David E. G. , Chan Sek Kwan 
Published: April 2005

AbstractIt is well known that water‐based commercial explosives locally ignited in closed vessels do not undergo self‐sustained combustion when the pressure is lower than some threshold value. The latter is usually referred to as the Minimum Burning Pressure (MBP) of the explosive and is now being used by some manufacturers as a basis of safety for many associated manufacture, transport, and handling processes. In the present work, both an apparatus based on hot‐wire ignition and an associated methodology were developed to measure the MBP of water‐based explosives. Typical results for various emulsion and water‐gel explosives are also reported and discussed. It is also shown that the technique could be used to characterize very insensitive explosive substances normally used as explosive precursors.