bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrochemical Preparation of Poly(Malachite Green) Film Modified Nafion‐Coated Glassy Carbon Electrode and Its Electrocatalytic Behavior Towards NADH, Dopamine and Ascorbic Acid
Authors: Chen Shen‐Ming , Chen Ji‐Yan , Thangamuthu R. 
Published: May 2007

AbstractPoly(malachite green) film modified Nafion‐coated glassy carbon electrodes have been prepared by potentiodynamic cycling in malachite green solution. The pH of polymerisation solution has only minor effect on film formation. Electrochemical quartz crystal microbalance (EQCM) was used to monitor the growth of the poly(malachite green) film. Cyclic voltammogram of the poly(malachite green) film shows a redox couple with well‐defined peaks. The redox response of the modified electrode was found to be depending on the pH of the contacting solution. The peak potentials were shifted to a less positive region with increasing pH and the dependence of the peak potential was found to be 56 mV per pH unit. The electrocatalytic behavior of poly(malachite green) film modified Nafion‐coated glassy carbon electrodes was tested towards oxidation of NADH, dopamine, and ascorbic acid. The oxidation of dopamine and ascorbic acid occurred at less positive potential on poly(malachite green) film compared to bare glassy carbon electrode. In the case of NADH, the overpotential was reduced substantially on modified electrode. Finally, the feasibility of utilizing poly(malachite green) film electrode in analytical estimation of ascorbic acid was demonstrated in flow injection analysis.
Fragility assessment of building structural systems in Mid‐America
Authors: Ellingwood Bruce R. , Celik Ozan Cem , Kinali Kursat 
Published: May 2007

AbstractUncertainty in response of buildings and other civil infrastructure to earthquake ground motion is due to the inherent randomness in the ground motion itself—peak intensity, time‐varying amplitude and strong‐motion duration, and frequency content—and local design and construction practices. In the recently completed SAC project and ongoing research in the Pacific Earthquake Engineering Research (PEER) Center, the focus is on performance of buildings designed for regions of high seismicity. In contrast, current research in the Mid‐America Earthquake (MAE) Center is examining the potential impact of earthquakes on building construction in regions of low‐to‐moderate seismicity in the Central and Eastern United States (CEUS) where design and construction practices seldom have made provision for earthquake resistance. This paper assesses the seismic fragilities of several typical low‐to‐mid‐rise steel and reinforced concrete buildings representative of design and construction practices in the CEUS. A comparison of these fragilities with those incorporated in HAZUS carries implications for damage and loss estimation in this region. Copyright © 2007 John Wiley & Sons, Ltd.
Noncanonical spike‐related BOLD responses in focal epilepsy
Authors: Lemieux Louis , Laufs Helmut , Carmichael David , Paul Joseph Suresh , Walker Matthew C. , Duncan John S. 
Published: May 2007

AbstractTill now, most studies of the Blood Oxygen Level‐Dependent (BOLD) response to interictal epileptic discharges (IED) have assumed that its time course matches closely to that of brief physiological stimuli, commonly called the canonical event‐related haemodynamic response function (canonical HRF). Analyses based on that assumption have produced significant response patterns that are generally concordant with prior electroclinical data. In this work, we used a more flexible model of the event‐related response, a Fourier basis set, to investigate the presence of other responses in relation to individual IED in 30 experiments in patients with focal epilepsy. We found significant responses that had a noncanonical time course in 37% of cases, compared with 40% for the conventional, canonical HRF‐based approach. In two cases, the Fourier analysis suggested activations where the conventional model did not. The noncanonical activations were almost always remote from the presumed generator of epileptiform activity. In the majority of cases with noncanonical responses, the noncanonical responses in single‐voxel clusters were suggestive of artifacts. We did not find evidence for IED‐related noncanonical HRFs arising from areas of pathology, suggesting that the BOLD response to IED is primarily canonical. Noncanonical responses may represent a number of phenomena, including artefacts and propagated epileptiform activity. Hum Brain Mapp 2008. © 2007 Wiley‐Liss, Inc.
Specific Processes and Scrambling in the Dehydrogenation of Ethane and the Degenerate Hydrogen Exchange in the Gas‐Phase Ion Chemistry of the Ni(C,H3,O)+/C2H6 Couple
Authors: Schlangen Maria , Schwarz Helmut , Schröder Detlef 
Published: May 2007

AbstractA mechanistically unprecedented situation characterizes the gas‐phase ion chemistry of Ni(C,H3,O)+ when reacted under thermal, single‐collision conditions with ethane. A dehydrogenation channel leading to Ni(C3,H7,O)+ is to 90% preceded by a complete loss of positional identity of all nine H‐atoms of the encounter complex (‘scrambling’), whereas ca. 10% of the reaction exhibit a selective CH bond activation of the alkane. In addition, a degenerate H exchange between ethane and the (C,H3,O) unit occurs as a side reaction, the mechanistic details of which remain unknown for the time being.
Synthesis and Qualitative Olfactory Evaluation of Benzodioxepine Analogues
Authors: Drevermann Britta , Lingham Anthony R. , Hügel Helmut M. , Marriott Philip J. 
Published: May 2007

AbstractMarine fragrances, particularly Calone 1951® (=7‐methyl‐2H‐1,5‐benzodioxepin‐3(4H)‐one; 1) has carved a minor but distinct niche in the broad field of fragrance chemistry. By focusing on the polar structure fragment of the benzodioxepinone parent compound, we set out to determine the molecular influence on the dominant marine note attributed to the Calone 1951® structure. A selection of one‐step modifications of the ketone 1 resulted in a range of odor‐active conformers with diverse olfactory attributes. The synthesis of a range of benzodioxepine analogues, i.e., of 3–11, is presented alongside olfactory evaluation (Tables 2 and 3). Removal of the carbonyl group of 1 and increasing the size of the aliphatic ring portion (see 6 and 7) introduced sweetness and a predominant loss of the marine character.
Oligonucleotide Analogues with Integrated Bases and Backbone. Part 15
Authors: Zhang Xiaomin , Bernet Bruno , Vasella Andrea 
Published: May 2007

AbstractThe self‐complementary (Z)‐configured U*[ce]A(*) dinucleotide analogues 6, 8, 10, 12, 14, and 16, and the A*[ce]U(*) dimers 19, 21, 23, 25, 27, and 29 were prepared by partial hydrogenation of the corresponding ethynylene linked dimers. Photolysis of 14 led to the (E)‐alkene 17. These dinucleotide analogues associate in CDCl3 solution, as evidenced by NMR and CD spectroscopy. The thermodynamic parameters of the duplexation were determined by van't Hoff analysis. The (Z)‐configured U*[ce]A(*) dimers 14 and 16 form cyclic duplexes connected by Watson–Crick H‐bonds, the (E)‐configured U*[ce]A dimer 17 forms linear duplexes, and the U*[ce]A(*) allyl alcohols 6, 8, 10, and 12 form mixtures of linear and cyclic duplexes. The C(6/I)‐unsubstituted A*[ce]U allyl alcohols 19 and 23 form linear duplexes, whereas the C(6/I)‐substituted A*[ce]U* allyl alcohols 21 and 25, and the C(5′/I)‐deoxy A*[ce]U(*) dimers 27 and 29 also form minor amounts of cyclic duplexes. The influence of intra‐ and intermolecular H‐bonding of the allyl alcohols and the influence of the base sequence upon the formation of cyclic duplexes are discussed.
Donor/Acceptor Effects on the Linear and Nonlinear Optical Properties of Geminal Diethynylethenes (g‐DEEs)
Authors: Zhao Yuming , Zhou Ningzhang , Slepkov Aaron D. , Ciulei Sorin C. , McDonald Robert , Hegmann Frank A. , Tykwinski Rik R. 
Published: May 2007

AbstractA series of geminal diethynylethenes (g‐DEEs) with electron‐donating and/or electron‐accepting (D/A) groups were synthesized via a Pd‐catalyzed cross‐coupling sequence. The UV/VIS spectra for donor–acceptor (D–A) functionalized g‐DEEs 5, 8, and 11 show distinctive absorption trends attributable to intramolecular charge‐transfer (ICT). The bond‐length‐alternation (BLA) index for the cross‐conjugated enediyne framework varies slightly with different terminal substituents as determined by density‐functional theory (DFT) calculations and single‐crystal X‐ray analysis. Ultrafast third‐order optical nonlinearities for the g‐DEEs were measured by the differential optical Kerr effect (DOKE) technique and show that terminal donor–acceptor substitution of g‐DEEs enhances molecular second hyperpolarizabilities (γ) in comparison to donor or acceptor g‐DEEs. A small increase in the two‐photon‐absorption cross‐section (σ(2)) is observed in the series 9–11 as a result of increased functionalization. The effects of donor/acceptor substitution on electron delocalization along the cross‐conjugated enediyne structure are evaluated on the basis of natural‐bond‐orbital (NBO) analysis. Solid‐state structures of the four derivatives 3b, 4b, 7 and 8 were characterized by single‐crystal X‐ray structural analysis and show an asymmetric unit cell for one derivative, D–A g‐DEE 8.
A Novel Method for the Asymmetric Synthesis of α,β‐Diamino Acids by a Glucose‐Mediated Stereoselective Strecker Reaction
Authors: Wang Dong , Zhang Peng‐Fei , Yu Biao 
Published: May 2007

AbstractA novel method for the asymmetric synthesis of α,β‐diamino acids by using the 2,3,4,6‐tetra‐O‐pivaloyl‐β‐D‐glucopyranosyl group (Piv4Glc) as chiral auxiliary was developed (Table and Scheme). The reaction was promoted by CuBr⋅Me2S as Lewis acid, and high yields and good diastereoselectivities were achieved.
Synthesis and Structure of 2‐Substituted Thieno[3′,2′:5,6]pyrido[4,3‐d]pyrimidin‐4(3H)‐one Derivatives
Authors: Liu Jian‐Chao , He Hong‐Wu , Ding Ming‐Wu 
Published: May 2007

AbstractA series of new 2‐substituted 3‐(4‐chlorophenyl)‐5,8,9‐trimethylthieno[3′,2′: 5,6]pyrido[4,3‐d]pyrimidin‐4(3H)‐ones 8 were synthesized via an aza‐Wittig reaction. Phosphoranylideneamino derivatives 6a or 6b reacted with 4‐chlorophenyl isocyanate to give carbodiimide derivatives 7a or 7b, respectively, which were further treated with amines or phenols to give compounds 8 in the presence of a catalytic amount of EtONa or K2CO3. The structure of 2‐(4‐chlorophenoxy)‐3‐(4‐chlorophenyl)‐5,8,9‐trimethylthieno[3′,2′: 5,6]pyrido[4,3‐d]pyrimidin‐4(3H)‐one (8j) was comfirmed by X‐ray analysis.
Evaluating the potential of a blended passive microwave‐interactive multi‐sensor product for improved mapping of snow cover and estimations of snow water equivalent
Authors: Kongoli Cezar , Dean Charles A. , Helfrich Sean R. , Ferraro Ralph R. 
Published: May 2007

AbstractThe retrieval of Snow Water Equivalent (SWE) from remote sensing satellites continues to be a very challenging problem. In this paper, we evaluate the accuracy of a new SWE product derived from the blending of a passive microwave SWE product based on the Advanced Microwave Sounding Unit (AMSU) with a multi‐sensor snow cover extent product based on the Interactive Multi‐sensor Snow and Ice Mapping System (IMS). The microwave measurements have the ability to penetrate the snow pack, and thus, the retrieval of SWE is best accomplished using the AMSU. On the other hand, the IMS maps snow cover more reliably due to the use of multiple satellite and ground observations. The evolution of global snow cover from the blended, the AMSU and the IMS products was examined during the 2006 snow season. Despite the overall good inter‐product agreement, it was shown that the retrievals of snow cover extent in the blended product are improved when using IMS, with implications for improved microwave retrievals of SWE. In a separate investigation, the skill of the microwave SWE product was also examined for its ability to correctly estimate SWE globally and regionally. Qualitative evaluation of global SWE retrievals suggested dependence on land surface temperature: the lower the temperature, the higher the SWE retrieved. This temperature bias was attributed in part to temperature effects on those snow properties that impact microwave response. Therefore, algorithm modifications are needed with more dynamical adjustments to account for changing snow cover. Quantitative evaluation over Slovakia in central Europe, for a limited period in 2006, showed reasonably good performance for SWE less than 100 mm. Sensitivity to deeper snow decreased significantly. Copyright © 2007 John Wiley & Sons, Ltd.
Oxidative damage in mild cognitive impairment and early Alzheimer's disease
Authors: Lovell Mark A. , Markesbery William R. 
Published: May 2007

AbstractIncreasing evidence supports a role for oxidative damage in the pathogenesis of Alzheimer's disease (AD). Multiple studies show significantly increased levels of lipid peroxidation and protein, DNA, and RNA oxidation in vulnerable regions of the brain of patients with late‐stage AD (LAD). More recent studies of patients with amnestic mild cognitive impairment (MCI), the earliest clinical manifestation of AD, show similar patterns of oxidative damage. These observations suggest that oxidative damage to critical biomolecules occurs early in the pathogenesis of AD and precedes pronounced neuropathologic alterations. Because oxidative damage begins early in the progress of the disease, it represents a potential therapeutic target for slowing the onset and progression of AD. © 2007 Wiley‐Liss, Inc.
β‐amyloid (25–35) enhances lipid metabolism and protein ubiquitination in cultured neurons
Authors: Cazzaniga Emanuela , Bulbarelli Alessandra , Cassetti Arianna , Lonati Elena , Re Francesca , Palestini Paola , Mutoh Tatsuro , Masserini Massimo 
Published: May 2007

AbstractWe investigated the effect of β‐amyloid (Aβ) (25–35), a cytotoxic fragment of Aβ peptide, on lipid metabolism and protein ubiquitination in cultured rat hippocampal neurons. After treatment with Aβ under conditions leading to apoptotis, as assessed by caspase activity assay, the total cell mass of lipids changed following a biphasic behavior, with an increase that reached a maximum after 16 hr of treatment, followed by a decrease. The increase at 16 hr was 15.3% in the case of phospholipids and 103.0% in the case of gangliosides and was due to enhanced biosynthesis as confirmed by increase of radioactivity incorporation (phospholipids +52.0%, gangliosides +193.1%) in cells fed with tritiated palmitic acid. No change with respect to cholesterol was observed. Strikingly, under these conditions, the ubiquitination state of cell proteins strongly increased. These effects were not observed with the (35–25) reverse sequence peptide. Similarly to Aβ, lactacystin treatment increased lipid synthesis and protein ubiquitination; only lactacystin, and not Aβ, induced a strong decrease of proteasome chimotrypsin activity. These results suggest that Aβ enhances protein ubiquitination, without inhibiting proteasomal activity, and lipid synthesis. These results may shed new light on the mechanisms of Aβ toxicity. © 2007 Wiley‐Liss, Inc.
Regulatory factor X4 variant 3: A transcription factor involved in brain development and disease
Authors: Zhang Donghui , Zeldin Darryl C. , Blackshear Perry J. 
Published: May 2007

AbstractRegulatory factor X4 variant 3 (RFX4_v3) is a recently identified transcription factor specifically expressed in the brain. Gene disruption in mice demonstrated that interruption of a single allele (heterozygous, +/–) prevented formation of the subcommissural organ (SCO), resulting in congenital hydrocephalus, whereas interruption of two alleles (homozygous, –/–) caused fatal failure of dorsal midline brain structure formation. These mutagenesis studies implicated RFX4_v3 in early brain development as well as the genesis of the SCO. Rfx4_v3 deficiency presumably causes abnormalities in brain by altering the expression levels of many genes that are crucial for brain morphogenesis, such as the signaling components in the Wnt, bone morphogenetic protein, and retinoic acid pathways. RFX4_v3 might affect these critical signaling pathways in brain development. Cx3cl1, a chemokine gene highly expressed in brain, was identified as a direct target for RFX4_v3, indicating that RFX4_v3 possesses trans‐acting activity to stimulate gene expression. Rfx4_v3 is highly expressed in the suprachiasmatic nucleus and might be involved in regulating the circadian clock. One haplotype in RFX4_v3 gene is linked to a higher risk of bipolar disorder, suggesting that this protein might contribute to the pathogenesis of the disease. This Mini‐Review describes our current knowledge about RFX4_v3, an important protein that appears to be involved in many aspects of brain development and disease. © 2007 Wiley‐Liss, Inc.
Peroxynitrite‐mediated oxidative damage to brain mitochondria: Protective effects of peroxynitrite scavengers
Authors: Singh Indrapal N. , Sullivan Patrick G. , Hall Edward D. 
Published: May 2007

AbstractPeroxynitrite‐mediated oxidative damage has been implicated in brain mitochondrial respiratory dysfunction after traumatic brain injury (TBI), which precedes the onset of neuronal loss. The aim of this study was to investigate the detrimental effects of the peroxynitrite donor SIN‐1 (3‐morpholinosydnonimine) on isolated brain mitochondria and to screen penicillamine, a stoichiometric (1:1) peroxynitrite‐scavenging agent, and tempol, a catalytic scavenger of peroxynitrite‐derived radicals, as antioxidant mitochondrial protectants. Exposure of the isolated mitochondria to SIN‐1 caused a significant dose‐dependent decrease in the respiratory control ratio and was accompanied by a significant increase in state II respiration, followed by significant decreases (P < 0.05) in states III and V. These functional alterations occurred together with significant increases in mitochondrial protein carbonyl (PC), lipid peroxidation–related 4‐hydroxynonenal (4‐HNE), and 3‐nitrotyrosine (3‐NT) content. Penicillamine hydrochloride (10 μM) partially but significantly (P < 0.05) protected against SIN‐1‐induced decreases in states III and V. However, a 2.5 μM concentration of tempol was able to significantly antagonize a 4‐fold molar excess (10 μM) concentration of SIN‐1 as effectively as were higher tempol concentrations, consistent with the likelihood that tempol works by a catalytic mechanism. The protection of mitochondrial respiration by penicillamine and tempol occurred in parallel with attenuation of PC, 4‐HNE, and 3‐NT. These results indicate that SIN‐1 causes mitochondrial oxidative damage and complex I dysfunction and that antioxidant compounds that target either peroxynitrite or its radicals may be effective mitochondrial protectants in the treatment of neural injury. © 2007 Wiley‐Liss, Inc.
Evidence that nucleocytoplasmic Olig2 translocation mediates brain‐injury‐induced differentiation of glial precursors to astrocytes
Authors: Magnus Tim , Coksaygan Turhan , Korn Thomas , Xue Haipeng , Arumugam Thiruma V. , Mughal Mohamed R. , Eckley D. Mark , Tang Sung‐Chun , DeTolla Louis , Rao Mahendra S. , Cassiani‐Ingoni Riccardo , Mattson Mark P. 
Published: May 2007

AbstractThe mechanisms by which neural and glial progenitor cells in the adult brain respond to tissue injury are unknown. We studied the responses of these cells to stab wound injury in rats and in two transgenic mouse models in which Y/GFP is driven either by Sox2 (a neural stem cell marker) or by Tα‐1 (which marks newly born neurons). The response of neural progenitors was low in all nonneurogenic regions, and no neurogenesis occurred at the injury site. Glial progenitors expressing Olig2 and NG2 showed the greatest response. The appearance of these progenitors preceded the appearance of reactive astrocytes. Surprisingly, we found evidence of the translocation of the transcription factor Olig2 into cytoplasm in the first week after injury, a mechanism that is known to mediate the differentiation of astrocytes during brain development. Translocation of Olig2, down‐regulation of NG2, and increased glial fibrillary acidic protein expression were recapitulated in vitro after exposure of glial progenitors to serum components or bone morphogentic protein by up‐regulation of Notch‐1. The glial differentiation and Olig2 translocation could be blocked by inhibition of Notch‐1 with the γ‐secretase inhibitor DAPT. Together, these data indicate that the prompt maturation of numerous Olig2+ glial progenitors to astrocytes underlies the repair process after a traumatic injury. In contrast, neural stem cells and neuronal progenitor cells appear to play only a minor role in the injured adult CNS. © 2007 Wiley‐Liss, Inc.
Locally delivered lovastatin nanoparticles enhance fracture healing in rats
Authors: Garrett I.R. , Gutierrez G.E. , Rossini G. , Nyman J. , McCluskey B. , Flores A. , Mundy G.R. 
Published: May 2007

AbstractStatins stimulate bone formation in vitro and in vivo and, when given in large doses or by prolonged infusions, stimulate biomechanical strength of murine long bones with healing fractures. However, administration of statins by large oral doses or prolonged infusions to a fracture site is not a feasible therapeutic approach to hasten healing of human fractures. We administered lovastatin in biodegradable polymer nanobeads of poly(lactic‐co‐glycolide acid) to determine if lovastatin delivered in low doses in nanoparticles of a therapeutically acceptable scaffold could increase rates of healing in a standard preclinical model of femoral fracture. We found that these nanobeads: (1) stimulated bone formation in vitro at 5 ng/mL, (2) increased rates of healing in femoral fractures when administered as a single injection into the fracture site, and (3) decreased cortical fracture gap at 4 weeks as assessed by microcomputed tomography. These preclinical results suggest that lovastatin administered in a nanobead preparation may be therapeutically useful in hastening repair of human fractures. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:1351–1357, 2007
Decreased muscle loading delays maturation of the tendon enthesis during postnatal development
Authors: Thomopoulos Stavros , Kim Hyun‐Min , Rothermich Stefan Y. , Biederstadt Carrie , Das Rosalina , Galatz Leesa M. 
Published: May 2007

AbstractPhysical environment influences the development and maintenance of musculoskeletal tissues. The current study uses an animal model to explore the role of the physical environment on the postnatal development of the supraspinatus tendon enthesis. A supraspinatus intramuscular injection of botulinum toxin A was used to paralyze the left shoulders of mice at birth. The supraspinatus muscles of right shoulders were injected with saline to serve as contralateral controls. The supraspinatus enthesis was examined after 14, 21, 28, and 56 days of postnatal development. Histologic assays were used to examine fibrocartilage morphology and percentage osteoclast surface. Micro‐computed tomography was used to examine muscle geometry and bone architecture. At 14 days there were no differences between groups in fibrocartilage formation, muscle geometry, bone architecture, or osteoclast surface. When comparing groups at 21, 28, and 56 days, muscle volume was decreased, fibrocartilage development was delayed, mineralized bone was decreased, and osteoclast surface was higher at each timepoint in the botulinum group compared to the contralateral saline control group. Our results indicate that the development of the tendon enthesis is sensitive to its mechanical environment. A reduction in muscle loading delayed the development of the tendon‐to‐bone insertion site by impeding the accumulation of mineralized bone. Physical factors did not play a significant role in enthesis maturation in the first 14 days postnatally, implying that biologic factors may drive early postnatal development. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:1154–1163, 2007