bluuebunny/crossref_metadata_2025 huggingface dataset:
Patterns of agreement among parent, teacher and youth ratings in a referred sample
Authors: Salbach-Andrae Harriet , Lenz Klaus , Lehmkuhl Ulrike
Published: September 2008

Objective

The purpose of this study was to investigate the degree of agreement among parents, teachers and adolescents with respect to the Child Behavior Checklist (CBCL), the Teacher's Report Form (TRF), and the Youth Self Report (YSR). In addition we evaluated the suitability of these three forms (CBCL, TRF and YSR) in terms of their contribution to understanding internalizing and externalizing disorders in youths being referred to a child and adolescent unit of a psychiatric care facility.

Methods

A total of 611 patients aged 11–18 years (mean age 13.0, SD 1.6) were assessed using the CBCL, the TRF and the YSR.

Results

Intraclass coefficients (ICC) showed low to moderate agreement among informants. Furthermore, the level of agreement was generally less among patients suffering from internalizing disorders than for young patients who displayed externalizing disorders. Logistic regression revealed that the TRF internalizing syndrome scale, the CBCL internalizing syndrome scale and gender were relevant prognostic factors for the occurrence of internalizing disorders in youth. The YSR internalizing syndrome scale, on the other hand, was not a relevant factor among adolescents of a clinical target population. Likewise, only the TRF externalizing syndrome scale, the CBCL externalizing syndrome scale and gender were relevant prognostic factors for the occurrence of externalizing disorders in youth.

Conclusions

Particularly the CBCL and TRF are useful instruments in assessing internalizing and externalizing disorders in adolescents referred to a mental health setting.
GO6976 prevents TNF‐α‐induced suppression of adiponectin expression in 3T3‐L1 adipocytes: Putative involvement of protein kinase C
Authors: Lim Joong-Yeon , Kim Won Ho , Park Sang Ick
Published: September 2008

Adiponectin, one of the adipokines secreted by adipocytes, possesses insulin sensitizing and anti‐atherosclerotic properties. Tumor necrosis factor‐alpha (TNF‐α) is known to suppress the expression and secretion of adiponectin in adipocytes; however, the underlying mechanism remains poorly understood. Here, we demonstrate that GO6976 (a selective inhibitor of conventional protein kinase C (PKC)) prevents TNF‐α‐induced suppression of adiponectin secretion and expression in fully differentiated 3T3‐L1 adipocytes, accompanied by attenuation of c‐Jun N‐terminal kinase (JNK) activation. Additionally, the transcriptional activity of peroxisome proliferator‐activated receptor‐gamma (PPARg) (a strong inducer of adiponectin) on the adiponectin promoter was inhibited in a PKC isoform‐specific manner. These results raise the possibility that PKC is involved in TNF‐α‐induced suppression of adiponectin in 3T3‐L1 adipocytes.
Midlife activity predicts risk of dementia in older male twin pairs
Authors: Carlson Michelle C. , Helms Michael J. , Steffens David C. , Burke James R. , Potter Guy G. , Plassman Brenda L.
Published: September 2008

Background

This was a prospective study of dementia to elucidate mechanisms of disease risk factors amenable to modification and specifically to determine whether midlife cognitive and physical leisure activities are associated with delayed onset or reduced risk of dementia within older male twin pairs.

Methods

The co‐twin control design used prospectively collected exposure information to predict risk of dementia 20 to 40 years later. The subjects were community‐dwelling and nursing home residents living throughout the continental United States. We studied 147 male twin‐pairs who were discordant for dementia or age of dementia onset and were members of the National Academy of Sciences–National Research Council Twin Registry of World War II veterans and participants in the Duke Twins Study of Memory in Aging. The main outcome measure was diagnosed dementia by using a two‐stage screen and full clinical evaluation. Conditional odds ratios were estimated for the association between midlife leisure activities and late‐life dementia.

Results

Greater midlife cognitive activity was associated with a 26% risk reduction for dementia onset. Protective effects were most robust in monozygotic twin pairs, where genetic and early‐life influences were most tightly controlled, and for activities that were often cognitive and social in nature. Cognitive activity was particularly protective among monozygotic twin pairs carrying the apolipoprotein E ε4 allele, with a 30% risk reduction. Midlife physical activity did not modify dementia risk.

Conclusions

Participation in a range of cognitively and socially engaging activities in midlife reduced risk for dementia and AD in twins discordant for onset, particularly among twin pairs at elevated genetic risk, and might be indicative of an enriched environment.
Topical Hemostatic Agents in Surgery: A Surgeon's Perspective
Authors: Samudrala Srinath
Published: September 2008

GOOD HEMOSTASIS IN SURGERY can provide multiple advantages to the patient, surgical team, and health care facility. Active and passive hemostatic agents have been widely used for many years and have extensive history supporting effective and safe use in a wide variety of surgical procedures.

THE TYPE OF SURGICAL PROCEDURE, type of bleeding, hemostatic agent availability, and patient characteristics will influence the choice of topical hemostatic agent that is used by the surgeon. By actively participating in the coagulation cascade, active topical hemostatic agents are more able to meet the criteria of an ideal hemostatic agent in cases of oozing blood and minor bleeding during surgical procedures. Active agents can be used alone or in combination with passive agents.

FAMILIARITY WITH THE PRODUCTS used to achieve hemostasis and their preparation can facilitate optimal use by surgical teams. AORN J 88 (September 2008) S1‐S11. © AORN, Inc, 2008.
A Dutiful Child: The Implications of Article 31 of the African
Children's Charter
Authors: Sloth-Nielsen J , Mezmur BD
Published: September 2008

Each right has a corresponding duty. The African Children's Charter,
under article 31, imposes a range of duties on children. Understandably, it
could become contentious when an instrument on the rights and welfare of
children expressly imposes duties on them. After setting the platform for
discussion by highlighting international experiences and outlining the African
concept of human rights, this article critically examines and attempts to
clarify the precise meaning, content, conditions of compliance and application
of those duties for children. By way of conclusion, it suggests that article 31
represents a valuable addition to the international human rights agenda, and
that a purposeful interpretation of its constituent parts reveals that children
should be required to play a role at family, community, national and continental
levels, in accordance with their age and maturity as they grow up, as part and
parcel of their heritage, empowerment and developing citizenship.
Sexual Harassment in the Workplace in South Africa: The Unlimited Vicarious Liability of Employers?
Authors: Ntsanyu Nana Constantine
Published: September 2008

The South African Supreme Court of Appeal and Constitutional Court have ruled that the employer is vicariously liable for sexual violence perpetrated by his employee on a co-employee or on a third party in the workplace or in what can be considered as an extension of the workplace. This is similar to the current position in the United Kingdom. This article questions the rationale of holding employers vicariously liable for intentional acts of employees such as sexual harassment. In a bid to justify their position, these courts have adopted a sort of vicarious liability with no outer limit that is both needless and tortuous. This article submits that the law imposes a duty on employers to protect their employees and that this unwarranted development of vicarious liability could be avoided if due regard is given to the prescribed direct (and strict) liability of the employer.
Physical processes in laser interaction with porous low-density materials
Authors: Borisenko N.G. , Bugrov A.E. , Burdonskiy I.N. , Fasakhov I.K. , Gavrilov V.V. , Goltsov A.Yu. , Gromov A.I. , Khalenkov A.M. , Kovalskii N.G. , Merkuliev Yu.A. , Petryakov V.M. , Putilin M.V. , Yankovskii G.M. , Zhuzhukalo E.V.
Published: September 2008

New results obtained in experiments on laser irradiation (I = 5 × 1013 W/cm2, λ = 1.054 µm) of low-density (2–10 mg/cm3) porous materials (agar, triacetate cellulose, and foam polysterene) are presented and discussed from the standpoint of optimum porous material utilization in target designs for inertial confinement fusion. The influence of low-density material microstructure of irradiated samples on the absorption of laser radiation and the energy transfer processes was investigated using X-ray and optical diagnostic methods with high temporal and spatial resolution.
Angular distributions of ions emitted from laser plasma produced at various irradiation angles and laser intensities
Authors: Láska L. , Jungwirth K. , Krása J. , Krouský E. , Pfeifer M. , Rohlena K. , Velyhan A. , Ullschmied J. , Gammino S. , Torrisi L. , Badziak J. , Parys P. , Rosinski M. , Ryć L. , Wolowski J.
Published: September 2008

Angular distributions of currents and velocities (energies) of ions produced at various target irradiation angles and laser intensities ranged from 1010 W/cm2 to 1017 W/cm2 were analyzed. It was confirmed that for low laser intensities the ion current distributions are always peaked along the target normal. However, at laser intensities comparable to or higher than 1014 W/cm2, the preferred direction of ion emission strongly depends on the irradiation geometry (laser focus setting, the irradiation angle), and can be off the target normal. This is very likely caused by the non-linear interaction of the laser beam with produced plasma, in particular, by the action of ponderomotive forces and the laser beam self-focusing.
Rethinking geochemical feature of the Afar and Kenya mantle plumes and geodynamic implications
Authors: Meshesha Daniel , Shinjo Ryuichi
Published: September 2008

We discuss the spatial and temporal variation in the geochemistry of mantle sources which were sampled by the Eocene to Quaternary mafic magmas in the vicinity of the Afar and Kenya plume upwelling zones, East Africa. Despite the contributions of lithospheric and crustal sources, carefully screened Eocene to Quaternary mafic lavas display wide range of Sr‐Nd‐Pb isotopic and incompatible trace elemental compositions that can be attributed to significant intraplume heterogeneity. The geochemical variations reflect the involvement of at least four mantle plume components as sources for the northeastern Africa magmatism: (1) isotopically depleted but trace element‐enriched component; (2) component characterized by radiogenic Pb isotope signatures (HIMU?); (3) enriched mantle‐like component; and (4) high‐3He/4He‐type (as HT2‐type basalts) plume component. The first component disappears in the Miocene‐Quaternary magmatism, and the second component is hardly recognized after the eruption of Miocene basalt in southern Ethiopia. Plume‐unrelated depleted asthenosphere starts to involve at a nascent stage of seafloor spreading centers in the Red Sea and Gulf of Aden. The other two‐plume components have persisted from the late Eocene to present, but their proportions have changed through time and space. We propose a model of multiple impingements of plumelets within the broad upwelling zone connected to the African Superplume in the lower mantle beneath southern Africa. The plumelet contains a matrix of high‐3He/4He‐type component with blobs, streaks, or ribbons of other components.
Towards a robust test on North America warming trend and precipitable water content increase
Authors: Wang Jih‐Wang , Wang Ke , Pielke Roger A. , Lin John C. , Matsui Toshihisa
Published: September 2008

An increase in the atmospheric moist content has been generally assumed when the lower‐tropospheric temperature (Tcol) increases, with relative humidity holding steady. Rather than using simple linear regression, we propose a more rigorous trend detection method that considers time series memory. The autoregressive moving‐average (ARMA) parameters for the time series of Tcol, precipitable water vapor (PWAV), and total precipitable water content (PWAT) from the North American Regional Reanalysis data were first computed. We then applied the Monte Carlo method to replicate the ARMA time series samples to estimate the variances of their Ordinary Least Square trends. Student's t tests showed that Tcol from 1979 to 2006 increased significantly; however, PWAV and PWAT did not. This suggests that atmospheric temperature and water vapor trends do not follow the conjecture of constant relative humidity over North America. We thus urge further evaluations of Tcol, PWAV, and PWAT trends for the globe.
Validation of the CloudSat precipitation occurrence algorithm using the Canadian C band radar network
Authors: Hudak David , Rodriguez Peter , Donaldson Norman
Published: September 2008

The ability of CloudSat to detect precipitation in cold season cloud systems is examined using data from the Environment Canada C band weather radar at King City, Ontario. The factors complicating the comparison are the time mismatch, the differences in sensitivity, and the changes to the geometry of cross section with range from the ground radar, W band radar attenuation, and the effect of ground clutter. A total of 40 overpasses with precipitation were observed over the King City radar from September 2006 to April 2007. In about 14% of the precipitation profiles, time mismatches were diagnosed. When these cases were removed, the skill scores of the CloudSat precipitation occurrence product were excellent. The most frequent cause of a false detection was an incorrect precipitation threshold in the algorithm. The most frequent cause of a miss in detection was ground clutter removal of valid echoes by the algorithm. Overall, the CloudSat algorithm handled the effect of attenuation very well. Improvement to the algorithm would arise from a better tuning of the precipitation threshold, a threshold of −10 dBZ instead of −18 dBZ being more appropriate for winter storms in the Great Lakes area, and more effective ground clutter filtering in the lowest four range bins of the CloudSat data. The methodology employed here and the 1456 verified precipitation profiles from CloudSat can serve as a framework for a test bed to evaluate precipitation products from CloudSat.
Matrix‐guided cartilage regeneration in chondral defects
Authors: Wegener Bernd , Schrimpf Florian M. , Pietschmann Mathias F. , Milz Stefan , Berger‐Lohr Meike , Bergschmidt Philipp , Jansson Volkmar , Müller Peter E.
Published: September 2008

Small cartilage defects treated with microfracture show comparable clinical results to those treated with ACI (autologous chondrocyte implantation). Unfortunately, the regenerative tissue generated by microfracture treatment does not exhibit the structure and function of hyaline articular cartilage. Adult mesenchymal stem cells are supposed to be capable of differentiating according to mechanical stimuli, e.g. into chondrocytes, thus generating hyaline cartilage. The treatments used so far, such as the microfracture procedure, are only able to induce mechanically insufficient fibrocartilage. The purpose of the present study was to test the influence of a resorbable implant manufactured from PGLA (polyglycollic‐co‐lactic acid) fleece in combination with microfracture in the weight‐bearing area of the femoral condyle of mature sheep on cartilage repair. Artificial chondral defects (diameter: 8 mm) were created and treated with microfracture, with a PGLA implant alone or with a combination of both (n=6 for each group). Untreated empty defects served as controls. Under thorough pain control, full weight bearing was permitted immediately after the operation. After 12 weeks, the animals were killed and the operated knees were removed and histologically processed. First, the degree of covering of the defect with regenerative tissue was measured; then, the quality of the regenerate was evaluated using the score of O'Driscoll, Keeley and Salter [(1986) J. Bone Joint Surg. Am. 68, 1017–1035], which was modified to include histochemical labelling results. The combination of PGLA implant and microfracture led to a significant improvement of the quality of the regenerate when compared with microfracturing alone.
Palmitoylation of stathmin family proteins domain A controls Golgi versus mitochondrial subcellular targeting
Authors: Chauvin Stéphanie , Poulain Fabienne E. , Ozon Sylvie , Sobel André
Published: September 2008

Background information. Precise localization of proteins to specialized subcellular domains is fundamental for proper neuronal development and function. The neural microtubule‐regulatory phosphoproteins of the stathmin family are such proteins whose specific functions are controlled by subcellular localization. Whereas stathmin is cytosolic, SCG10, SCLIP and RB3/RB3′/RB3″ are localized to the Golgi and vesicle‐like structures along neurites and at growth cones. We examined the molecular determinants involved in the regulation of this specific subcellular localization in hippocampal neurons in culture.

Results. We show that their conserved N‐terminal domain A carrying two palmitoylation sites is dominant over the others for Golgi and vesicle‐like localization. Using palmitoylation‐deficient GFP (green fluorescent protein) fusion mutants, we demonstrate that domains A of stathmin proteins have the particular ability to control protein targeting to either Golgi or mitochondria, depending on their palmitoylation. This regulation involves the co‐operation of two subdomains within domain A, and seems also to be under the control of its SLD (stathmin‐like domain) extension.

Conclusions. Our results unravel that, in specific biological conditions, palmitoylation of stathmin proteins might be able to control their targeting to express their functional activities at appropriate subcellular sites. They, more generally, open new perspectives regarding the role of palmitoylation as a signalling mechanism orienting proteins to their functional subcellular compartments.
Developmental origin of adipocytes: new insights into a pending question
Authors: Billon Nathalie , Monteiro Miguel Caetano , Dani Christian
Published: September 2008

The current epidemic of obesity has caused a surge of interest in the study of adipose tissue formation. Much progress has been made in defining the transcriptional networks controlling the terminal differentiation of preadipocytes into mature adipocytes. However, the mechanisms that direct MSCs (mesenchymal stem cells) down the adipocyte lineage remain largely unknown. Similarly, although adipocytes are generally described to derive from mesoderm, the study of the developmental origin of MSCs and adipose tissues has been largely disregarded until now. Functional variations do exist between different adipose tissues, which suggest possible differences in their developmental origin and might explain why some depots are more associated than other to metabolic disorders. This review summarizes the surprising findings that have recently emerged from both embryonic stem cells and lineage‐tracing studies in vivo, unravelling an unsuspected developmental origin for MSCs and adipocytes in the neural crest.
Adiponectin induces interleukin‐6 production and activates STAT3 in adult mouse cardiac fibroblasts
Authors: Liao Wenqiang , Yu Changan , Wen Jianyan , Jia William , Li Geng , Ke Yuannan , Zhao Shumin , Campell William
Published: September 2008

Background information. APN (adiponectin), an adipocyte‐derived cytokine highly presented in serum, which exerts antidiabetic, anti‐atherosclerotic and cardioprotective actions, also enhances CFB (cardiac fibroblast) proliferation and protects against cardiac fibrosis. STAT3 (signal transducer and activator of transcription 3), a major mediator in the gp130/JAK2 (Janus kinase 2)/STATs signalling pathway, plays a critical role in cardioprotective events. Almost two‐thirds of total myocardial cells are CFBs; however, whether APN regulates STAT3 signalling pathway has not been clarified yet in CFBs. In the present study, we investigated the effect of recombinant globular APN on the STAT3 activity in adult mouse CFBs and explored the possible signalling transduction mechanism.

Results. In cultured CFBs, APN (10 μg/ml) can significantly induce delayed STAT3 Tyr705 phosphorylation time‐dependently, up to 60 min, and mediate STAT3 translocation from cytoplasm to nucleus. Transfection of siRNA (small interfering RNA) specific for AdipoR1 (APN receptor 1), but not AdipoR2, obviously inhibited APN‐induced STAT3 Tyr705 phosphorylation, indicating that AdipoR1, not AdipoR2, is required for STAT3 phosphorylation. Both inhibition of gp130 by anti‐gp130 neutralizing antibody and JAK2 by AG490 (a specific inhibitor for JAK2) can inhibit APN‐induced STAT3 phosphorylation and STAT3 transcription activity detected using 2×pAPRE‐Luc (APRE reporter) assay. Furthermore, we found that the IL (interleukin)‐6 level in culture medium was significantly increased after stimulation with APN and the IL‐6 mRNA level was also markedly increased in CFBs, which can be reversed by siRNA for AdipoR1, but not for AdipoR2, and that anti‐IL‐6 neutralizing antibody can significantly inhibit APN‐induced STAT3 Tyr705 phosphorylation.

Conclusions. APN induces IL‐6 production mediated by AdipoR1, not AdipoR2, in adult mouse CFBs, which leads to the stimulation of the gp130/JAK signalling pathway, and as a result causes STAT3 activation.
COMMD1 expression is controlled by critical residues that determine XIAP binding
Authors: Maine Gabriel N. , Mao Xicheng , Muller Patricia A. , Komarck Christine M. , Klomp Leo W. J. , Burstein Ezra
Published: September 2008

COMMD {COMM [copper metabolism Murr1 (mouse U2af1-rs1 region 1)] domain-containing} proteins participate in several cellular processes, ranging from NF-κB (nuclear factor κB) regulation, copper homoeostasis, sodium transport and adaptation to hypoxia. The best-studied member of this family is COMMD1, but relatively little is known about its regulation, except that XIAP [X-linked IAP (inhibitor of apoptosis)] functions as its ubiquitin ligase. In the present study, we identified that the COMM domain of COMMD1 is required for its interaction with XIAP, and other COMMD proteins can similarly interact with IAPs. Two conserved leucine repeats within the COMM domain were found to be critically required for XIAP binding. A COMMD1 mutant which was unable to bind to XIAP demonstrated a complete loss of basal ubiquitination and great stabilization of the protein. Underscoring the importance of IAP-mediated ubiquitination, we found that long-term expression of wild-type COMMD1 results in nearly physiological protein levels as a result of increased ubiquitination, but this regulatory event is circumvented when a mutant form that cannot bind XIAP is expressed. In summary, our findings indicate that COMMD1 expression is controlled primarily by protein ubiquitination, and its interaction with IAP proteins plays an essential role.
Identification of Tspan9 as a novel platelet tetraspanin and the collagen receptor GPVI as a component of tetraspanin microdomains
Authors: Protty Majd B. , Watkins Nicholas A. , Colombo Dario , Thomas Steven G. , Heath Victoria L. , Herbert John M. J. , Bicknell Roy , Senis Yotis A. , Ashman Leonie K. , Berditchevski Fedor , Ouwehand Willem H. , Watson Steve P. , Tomlinson Michael G.
Published: September 2008

Platelets are essential for wound healing and inflammatory processes, but can also play a deleterious role by causing heart attack and stroke. Normal platelet activation is dependent on tetraspanins, a superfamily of glycoproteins that function as ‘organisers’ of cell membranes by recruiting other receptors and signalling proteins into tetraspanin-enriched microdomains. However, our understanding of how tetraspanin microdomains regulate platelets is hindered by the fact that only four of the 33 mammalian tetraspanins have been identified in platelets. This is because of a lack of antibodies to most tetraspanins and difficulties in measuring mRNA, due to low levels in this anucleate cell. To identify potentially platelet-expressed tetraspanins, mRNA was measured in their nucleated progenitor cell, the megakaryocyte, using serial analysis of gene expression and DNA microarrays. Amongst 19 tetraspanins identified in megakaryocytes, Tspan9, a previously uncharacterized tetraspanin, was relatively specific to these cells. Through generating the first Tspan9 antibodies, Tspan9 expression was found to be tightly regulated in platelets. The relative levels of CD9, CD151, Tspan9 and CD63 were 100, 14, 6 and 2 respectively. Since CD9 was expressed at 49000 cell surface copies per platelet, this suggested a copy number of 2800 Tspan9 molecules. Finally, Tspan9 was shown to be a component of tetraspanin microdomains that included the collagen receptor GPVI (glycoprotein VI) and integrin α6β1, but not the von Willebrand receptor GPIbα or the integrins αIIbβ3 or α2β1. These findings suggest a role for Tspan9 in regulating platelet function in concert with other platelet tetraspanins and their associated proteins.
Kv4.2 is a locus for PKC and ERK/MAPK cross-talk
Authors: Schrader Laura A. , Ren Yajun , Cheng Feng , Bui Dui , Sweatt J. David , Anderson Anne E.
Published: September 2008

Transient outward K+ currents are particularly important for the regulation of membrane excitability of neurons and repolarization of action potentials in cardiac myocytes. These currents are modulated by PKC (protein kinase C) activation, and the K+- channel subunit Kv4.2 is a major contributor to these currents. Furthermore, the current recorded from Kv4.2 channels expressed in oocytes is reduced by PKC activation. The mechanism underlying PKC regulation of Kv4.2 currents is unknown. In the present study, we determined that PKC directly phosphorylates the Kv4.2 channel protein. In vitro phosphorylation of the intracellular N- and C-termini of Kv4.2 GST (glutathione transferase) tagged fusion protein revealed that the C-terminal of Kv4.2 was phosphorylated by PKC, whereas the N-terminal was not. Amino acid mapping and site-directed mutagenesis revealed that the phosphorylated residues on the Kv4.2 C-terminal were Ser447 and Ser537. A phospho-site-specific antibody showed that phosphorylation at the Ser537 site was increased in the hippocampus in response to PKC activation. Surface biotinylation experiments revealed that mutation to alanine of both Ser447 and Ser537 in order to block phosphorylation at both of the PKC sites increased surface expression compared with wild-type Kv4.2. Electrophysiological recordings of the wild-type and both the alanine and aspartate mutant Kv4.2 channels expressed with KChIP3 (Kv4 channel-interacting protein 3) revealed no significant difference in the half-activation or half-inactivation voltage of the channel. Interestingly, Ser537 lies within a possible ERK (extracellular-signal-regulated kinase)/MAPK (mitogen-activated protein kinase) recognition (docking) domain in the Kv4.2 C-terminal sequence. We found that phosphorylation of Kv4.2 by PKC enhanced ERK phosphorylation of the channel in vitro. These findings suggest the possibility that Kv4.2 is a locus for PKC and ERK cross-talk.
A cysteine-rich metal-binding domain from rubella virus non-structural protein is essential for viral protease activity and virus replication
Authors: Zhou Yubin , Tzeng Wen-Pin , Ye Yiming , Huang Yun , Li Shunyi , Chen Yanyi , Frey Teryl K. , Yang Jenny J.
Published: September 2008

The protease domain within the RUBV (rubella virus) NS (non-structural) replicase proteins functions in the self-cleavage of the polyprotein precursor into the two mature proteins which form the replication complex. This domain has previously been shown to require both zinc and calcium ions for optimal activity. In the present study we carried out metal-binding and conformational experiments on a purified cysteine-rich minidomain of the RUBV NS protease containing the putative Zn2+-binding ligands. This minidomain bound to Zn2+ with a stoichiometry of ≈0.7 and an apparent dissociation constant of <500 nM. Fluorescence quenching and 8-anilinonaphthalene-1-sulfonic acid fluorescence methods revealed that Zn2+ binding resulted in conformational changes characterized by shielding of hydrophobic regions from the solvent. Mutational analyses using the minidomain identified residues Cys1175, Cys1178, Cys1225 and Cys1227 were required for the binding of Zn2+. Corresponding mutational analyses using a RUBV replicon confirmed that these residues were necessary for both proteolytic activity of the NS protease and viability. The present study demonstrates that the CXXC(X)48CXC Zn2+-binding motif in the RUBV NS protease is critical for maintaining the structural integrity of the protease domain and essential for proteolysis and virus replication.
Myocardial ischaemia inhibits mitochondrial metabolism of 4-hydroxy-trans-2-nonenal
Authors: Hill Bradford G. , Awe Sunday O. , Vladykovskaya Elena , Ahmed Yonis , Liu Si-Qi , Bhatnagar Aruni , Srivastava Sanjay
Published: September 2008

Myocardial ischaemia is associated with the generation of lipid peroxidation products such as HNE (4-hydroxy-trans-2-nonenal); however, the processes that predispose the ischaemic heart to toxicity by HNE and related species are not well understood. In the present study, we examined HNE metabolism in isolated aerobic and ischaemic rat hearts. In aerobic hearts, the reagent [3H]HNE was glutathiolated, oxidized to [3H]4-hydroxynonenoic acid, and reduced to [3H]1,4-dihydroxynonene. In ischaemic hearts, [3H]4-hydroxynonenoic acid formation was inhibited and higher levels of [3H]1,4-dihydroxynonene and [3H]GS-HNE (glutathione conjugate of HNE) were generated. Metabolism of [3H]HNE to [3H]4-hydroxynonenoic acid was restored upon reperfusion. Reperfused hearts were more efficient at metabolizing HNE than non-ischaemic hearts. Ischaemia increased the myocardial levels of endogenous HNE and 1,4-dihydroxynonene, but not 4-hydroxynonenoic acid. Isolated cardiac mitochondria metabolized [3H]HNE primarily to [3H]4-hydroxynonenoic acid and minimally to [3H]1,4-dihydroxynonene and [3H]GS-HNE. Moreover, [3H]4-hydroxynonenoic acid was extruded from mitochondria, whereas other [3H]HNE metabolites were retained in the matrix. Mitochondria isolated from ischaemic hearts were found to contain 2-fold higher levels of protein-bound HNE than the cytosol, as well as increased [3H]GS-HNE and [3H]1,4-dihydroxynonene, but not [3H]4-hydroxynonenoic acid. Mitochondrial HNE oxidation was inhibited at an NAD+/NADH ratio of 0.4 (equivalent to the ischaemic heart) and restored at an NAD+/NADH ratio of 8.6 (equivalent to the reperfused heart). These results suggest that HNE metabolism is inhibited during myocardial ischaemia owing to NAD+ depletion. This decrease in mitochondrial metabolism of lipid peroxidation products and the inability of the mitochondria to extrude HNE metabolites could contribute to myocardial ischaemia/reperfusion injury.
Oral antioxidants and cardiovascular health in the exercise-trained and untrained elderly: a radically different outcome
Authors: Wray D. Walter , Uberoi Abhimanyu , Lawrenson Lesley , Bailey Damian M. , Richardson Russell S.
Published: September 2008

Both antioxidant supplementation and exercise training have been identified as interventions which may reduce oxidative stress and thus improve cardiovascular health, but the interaction of these interventions on arterial BP (blood pressure) and vascular function has not been studied in older humans. Thus in six older (71±2 years) mildly hypertensive men, arterial BP was evaluated non-invasively at rest and during small muscle mass (knee-extensor) exercise with and without a pharmacological dose of oral antioxidants (vitamins C and E, and α-lipoic acid). The efficacy of the antioxidant intervention to decrease the plasma free radical concentration was verified via EPR (electron paramagnetic resonance) spectroscopy, while changes in endothelial function in response to exercise training and antioxidant administration were evaluated via FMD (flow-mediated vasodilation). Subjects were re-evaluated after a 6-week aerobic exercise training programme. Prior to training, acute antioxidant administration did not change resting arterial BP or FMD. Six weeks of knee-extensor exercise training reduced systolic BP (from 150±8 mmHg at pre-training to 138±3 mmHg at post-training) and diastolic BP (from 91±5 mmHg at pre-training to 79±3 mmHg at post-training), and improved FMD (1.5±1 to 4.9±1% for pre- and post-training respectively). However, antioxidant administration after exercise training negated these improvements, returning subjects to a hypertensive state and blunting training-induced improvements in FMD. In conclusion, the paradoxical effects of these interventions suggest a need for caution when exercise and acute antioxidant supplementation are combined in elderly mildly hypertensive individuals.
Vacuum ultraviolet pulsed field ionization-photoelectron and infrared-photoinduced Rydberg ionization study of trans-1,3-butadiene
Authors: Hou Y. , Woo H.-K. , Wang P. , Xing X. , Ng C. Y. , Lau K.-C.
Published: September 2008

The vacuum ultraviolet (VUV) laser pulsed field ionization-photoelectron (PFI-PE) spectrum of trans-1,3-butadiene (trans-CH2CHCHCH2) has been measured in the region of 0–1700cm−1 above its ionization energy (IE) to probe the vibrational modes νi+ (i=1–18) of trans-CH2CHCHCH2+. The high-frequency vibrational modes νi+ (i=19, 22, and 23) of trans-CH2CHCHCH2+ have also been probed by the VUV-infrared-photoinduced Rydberg ionization (VUV-IR-PIRI) measurement. On the basis of the semiempirical simulation of the origin VUV-PFI-PE band, the IE(trans-CH2CHCHCH2) is determined to be 73150.1±1.5cm−1 (9.06946±0.00019eV). This value has been used to benchmark the state-of-the-art theoretical IE prediction based on the CCSD(T,Full)/CBS procedures, the calculation of which is reported in the present study. The vibrational bands observed in the VUV-PFI-PE and VUV-IR-PIRI spectra were assigned based on ab initio anharmonic vibrational frequencies and Franck–Condon factor calculations for the photoionization transitions. Combining the VUV-PFI-PE and VUV-IR-PIRI measurements, 17 fundamental vibrational frequencies of trans-CH2CHCHCH2+ have been determined, including ν1+=182±3, ν2+=300±3, ν3+=428±3, ν4+=514±3, ν5+=554±5, ν6+=901±3, ν7+=928±5, ν8+=994±3, ν9+=1008±5, ν10+=1094±5, ν13+=1258±3, ν14+=1293±3, ν16+=1479±3, ν18+=1620±3, ν19+=2985±10, ν22+=3030±10, and ν23+=3105±10cm−1.
Effect of donor orientation on ultrafast intermolecular electron transfer in coumarin-amine systems
Authors: Singh P. K. , Nath S. , Bhasikuttan A. C. , Kumbhakar M. , Mohanty J. , Sarkar S. K. , Mukherjee T. , Pal H.
Published: September 2008

Effect of donor amine orientation on nondiffusive ultrafast intermolecular electron transfer (ET) reactions in coumarin-amine systems has been investigated using femtosecond fluorescence upconversion measurements. Intermolecular ET from different aromatic and aliphatic amines used as donor solvents to the excited coumarin-151 (C151) acceptor occurs with ultrafast rates such that the shortest fluorescence lifetime component (τ1) is the measure of the fastest ET rate (τ1=τETfast=(kETfast)−1), assigned to the C151-amine contact pairs in which amine donors are properly oriented with respect to C151 to maximize the acceptor-donor electronic coupling (Vel). It is interestingly observed that as the amine solvents are diluted by suitable diluents (either keeping solvent dielectric constant similar or with increasing dielectric constant), the τ1 remains almost in the similar range as long as the amine dilution does not cross a certain critical limit, which in terms of the amine mole fraction (xA) is found to be ∼0.4 for aromatic amines and ∼0.8 for aliphatic amines. Beyond these dilutions in the two respective cases of the amine systems, the τ1 values are seen to increase very sharply. The large difference in the critical xA values involving aromatic and aliphatic amine donors has been rationalized in terms of the largely different orientational restrictions for the ET reactions as imposed by the aliphatic (n-type) and aromatic (π-type) nature of the amine donors [A. K. Satpati et al., J. Mol. Struct. 878, 84 (2008)]. Since the highest occupied molecular orbital (HOMO) of the n-type aliphatic amines is mostly centralized at the amino nitrogen, only some specific orientations of these amines with respect to the close-contact acceptor dye [also of π-character; A. K. Satpati et al., J. Mol. Struct. 878, 84 (2008) and E. W. Castner et al., J. Phys. Chem. A 104, 2869 (2000)] can give suitable Vel and thus ultrafast ET reaction. In contrary, the HOMO of the π-type aromatic amines is largely distributed throughout the whole molecule and thus most of the orientations of these amines can give significant Vel for ultrafast ET reactions with close-contact C151 dyes.
Local strain distributions in silicon-on-insulator/stressor-film composites
Authors: Kalenci Özgür , Murray Conal E. , Noyan I. C.
Published: September 2008

We have used scanning microdiffraction topography to determine the mismatch strains and local strain distributions in silicon-on-insulator substrates with overlying thin film stressor features. Analysis of the data using the edge-force model and the Ewald–von Laue dynamical diffraction theory shows the presence of an exponential strain gradient in the vicinity of the buried SiO2/Si-substrate interface. We show that, for simple geometries, it is possible to deduce the sign of the mismatch strain simply by inspecting the microdiffraction topograph.
Adaptive kinetic Monte Carlo for first-principles accelerated dynamics
Authors: Xu Lijun , Henkelman Graeme
Published: September 2008

The adaptive kinetic Monte Carlo method uses minimum-mode following saddle point searches and harmonic transition state theory to model rare-event, state-to-state dynamics in chemical and material systems. The dynamical events can be complex, involve many atoms, and are not constrained to a grid—relaxing many of the limitations of regular kinetic Monte Carlo. By focusing on low energy processes and asserting a minimum probability of finding any saddle, a confidence level is used to describe the completeness of the calculated event table for each state visited. This confidence level provides a dynamic criterion to decide when sufficient saddle point searches have been completed. The method has been made efficient enough to work with forces and energies from density functional theory calculations. Finding saddle points in parallel reduces the simulation time when many computers are available. Even more important is the recycling of calculated reaction mechanisms from previous states along the dynamics. For systems with localized reactions, the work required to update the event table from state to state does not increase with system size. When the reaction barriers are high with respect to the thermal energy, first-principles simulations over long time scales are possible.
Structural evolution of medium-sized Pdn (n=15–25) clusters from density functional theory
Authors: Zhang Hualei , Tian Dongxu , Zhao Jijun
Published: September 2008

Four types of possible structural motifs of the medium-sized Pdn (n=15–25) clusters i.e., fcc like, decahedron based, icosahedron based, and prolate ellipsoid based, have been generated from an empirical genetic algorithm search and further investigated using spin-polarized density functional theory calculations. fcc-like structures based on Pd19 octahedron dominate the growth pathway of Pdn clusters (n=15–23). For larger clusters such as Pd24 and Pd25, a prolate ellipsoid-based geometry and a structure consisting of three interpenetrating decahedra are energetically favorable, respectively. The size-dependent cluster properties as well as the correlation between electronic properties and cluster geometry are also discussed, suggesting a particular stability cluster at Pd19 with a fcc-like octahedron structure.
Growth interruption studies on vertically aligned 2-3 wall carbon nanotubes by water assisted chemical vapor deposition
Authors: Patole S. P. , Park J. H. , Lee T. Y. , Lee J. H. , Patole A. S. , Yoo J. B.
Published: September 2008

Highly aligned, 2-3 wall carbon nanotube (CNT) arrays were used to examine the kinetics of CNT growth. A growth interruption method was used to determine the in situ growth rate. The growth interruption method with a water vapor treatment or acetylene treatment during the interruption enabled the production of CNT stacks with different morphologies. The catalytic activity was also monitored using this method. The lifetime of the catalyst was predicted and verified using the catalyst decay model. High temperature metal oxidation behavior using parabolic curve fitting is assigned to the decay process. Details of the analysis are presented.
Giant sharp converse magnetoelectric effect from the combination of a piezoelectric transformer with a piezoelectric/magnetostrictive laminated composite
Authors: Wang Yaojin , Wang Feifei , Or Siu Wing , Chan Helen Lai Wa , Zhao Xiangyong , Luo Haosu
Published: September 2008

Giant sharp converse magnetoelectric (CME) coefficient of 11.9G∕V is obtained in a heterostructure formed by combining a Rosen-type 0.7Pb(Mg1∕3Nb2∕3)O3–0.3PbTiO3 (PMN-PT) piezoelectric single-crystal transformer with a CME laminated composite of a length-magnetized Tb0.3Dy0.7Fe1.92 (Terfenol-D) magnetostrictive alloy plate sandwiched between two thickness-polarized, electroparallel-connected PMN-PT piezoelectric single-crystal plates. The observed giant sharp CME is found to originate from the step-up voltage-gain effect in the transformer and the resonance CME effect in the laminated composite. This heterostructure has promising applications in electrically controlled magnetic memory devices.
Comment on “Effects of magnetic field gradient on ion beam current in cylindrical Hall ion source” [J. Appl. Phys. 102, 123305 (2007)]
Authors: Raitses Y. , Smirnov A. , Fisch N. J.
Published: September 2008

It is argued that the key difference in the cylindrical Hall thruster (CHT) as compared to the end-Hall ion source cannot be exclusively attributed to the magnetic field topology [Tang et al., J. Appl. Phys. 102, 123305 (2007)]. With a similar mirror-type topology, the CHT configuration provides the electric field with nearly equipotential magnetic field surfaces and a better suppression of the electron cross-field transport, as compared to both the end-Hall ion source and the cylindrical Hall ion source of [Tang et al., J. Appl. Phys. 102, 123305 (2007)].
Reconstructing atomistic detail for coarse-grained models with resolution exchange
Authors: Liu Pu , Shi Qiang , Lyman Edward , Voth Gregory A.
Published: September 2008

Coarse-grained (CG) modeling has emerged as a promising tool to bridge the gap between the temporal and spatial scales of all-atom (AA) simulations and those of many important biological processes. Resolution exchange, a variant of the replica exchange method, combines the efficiency of CG simulation and the accuracy of AA simulation by swapping configurations between AA and CG simulations. The crucial step in a resolution exchange move is to rigorously reconstruct the high-resolution system from models at coarser resolutions. In this paper, configurational-bias Monte Carlo is adopted as a general method to rebuild the missing degrees of freedom rigorously for CG models and for the first time combined with resolution exchange. The new approach is demonstrated on an alkane and a peptide system. It is found that the efficiency of resolution exchange depends significantly on the quality of the CG model.
Effect of ion composition on ion acceleration by magnetosonic shock waves
Authors: Toida Mieko , Higashino Hiroyuki , Ohsawa Yukiharu
Published: September 2008

The study of heavy-ion acceleration by magnetosonic shock waves in multi-ion-species plasmas [M. Toida and Y. Ohsawa, Solar Physics 171, 161 (1997)] is extended to the case in which the ion masses are of the same order of magnitude; specifically, the effect of mass and density ratios is examined for H-T and D-T plasmas with three-dimensional, electromagnetic, particle simulations. The frequency difference Δω, where Δω=(ω+0−ω−r)∕ω+0 with ω+0 the cut-off frequency of the high-frequency magnetosonic mode and ω−r the resonance frequency of the low-frequency mode, is a key parameter in the generation of shock waves from a disturbance. In H-T plasmas with nH⪡nT and with nH⪢nT and in D-T plasmas with any density ratio, Δω is small, and the high-frequency-mode shock wave is mainly generated and plays a central role in ion energization processes. In H-T plasmas with nH=nT, for which Δω is much greater, both the high- and low-frequency-mode shock waves are generated and contribute to the acceleration.
Ballooning filament growth in the intermediate nonlinear regime
Authors: Zhu P. , Hegna C. C.
Published: September 2008

A theory is developed for the description of ballooning instability in the intermediate nonlinear regime for general magnetic configurations including toroidal systems such as tokamaks. The evolution equations for the plasma filament growth induced by the ballooning instability are derived accounting for the dominant nonlinear effects in an ideal magnetohydrodynamic description. The intermediate nonlinear regime of ballooning modes is defined by the ordering that the plasma filament displacement across the magnetic surface is comparable to the linear mode width in the same direction. In the tokamak case, this regime could become particularly relevant for a transport barrier as the width of the barrier (or pedestal) region approaches the mode width of the dominant ballooning mode. A remarkable feature of the nonlinear ballooning equations is that solutions of the associated local linear ballooning mode equations continue to be valid solutions into the intermediate nonlinear regime. The filament growth equations for the intermediate nonlinear ballooning regime may be applicable to the precursor and precollapse phase of edge localized modes observed in both simulations and experiments.
Enhanced ac electrothermal fluidic pumping in microgrooved channels
Authors: Du E. , Manoochehri Souran
Published: September 2008

It is important to generate fast fluid flow yet maintain low temperature rise for ac electrothermal (ac ET) pumping in microsystems with conductive fluids. This has been generally the limitation of ac ET driven micropump applications. We present an enhanced ac ET pumping mechanism using low voltage ac signals that can result in a small amount of temperature rise. Different from the published traveling wave and asymmetric electrode structures positioned on insulated flat surfaces, channels with a microgrooved surface are utilized in this study. The effects of the microgroove existence on the modification of the ET body force and recession of the vortex backflows are demonstrated. Forward and backward pumping modes are identified and analyzed. This mechanism utilizes a thin film of asymmetric electrode structure on the microgrooved channel floor that can be fabricated with common planar lithography technologies. This study demonstrates that using the microgrooved structure can increase pumping capacity by five to sixfold as compared to a planar electrode arrangement with the same effective dimensions.