bluuebunny/crossref_metadata_2025 huggingface dataset:
Economical discretization schemes for the finite‐section method
Authors: Lebedeva E.V. , Solodky S.G.
Published: September 2008

A problem of economical discretization of equations, arising at the finite‐section approximation of Fredholm integral equations of the first kind on the half‐line, are investigated. The piecewise‐constant discretization schemes providing given accuracy are developed for finite‐section equations. The order estimates for the volume of used discrete information are calculated. The comparative analysis of the information expenses for proposed schemes and known earlier is given. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Null controllability of degenerate parabolic equations
Authors: Martinez Patrick , Cannarsa Piermaco , Vancostenoble Judith
Published: September 2008

Motivated by a boundary layer problem, we are interested in the controllability properties of parabolic equations degenerating at the boundary of the space domain.

We derive new Carleman estimates for a class of degenerate parabolic equation; the proof is based in particular on Hardytype inequalities. Then we deduce observability and null controllability results. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electromagnetic and thermal modelling of axisymmetric induction furnaces
Authors: Bermúdez A. , Gómez D. , Muñiz M.C. , Salgado P.
Published: September 2008

A numerical method to describe the thermo‐electric behavior of an induction heating furnace is introduced. It is obtained by using an enthalpy formulation concerning the thermal model and an integral representation of the electromagnetic potential in an unbounded domain. A BEM‐FEM method is used and an iterative algorithm together with numerical results for an industrial heating system are presented. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Design of robust signal and clock networks
Authors: Panitz P. , Olbrich M. , Barke E. , Buehler M. , Koehl J.
Published: September 2008

As technology scales down into the nanometer region new design challenges emerge. Wire delays become the performance bottleneck in VLSI circuits. Copper is introduced as new wiring material because of its low sheet resistivity, hence low signal propagation delay. The main defect mechanism shifts from shorts to opens due to the different manufacturing process for copper wires. Open defects limit functional yield. Parametric yield decreases because of timing uncertainties emerging from manufacturing variation. Clock skew variation becomes critical because it may shorten the cycle length of the critical path. The variation of signal nets has to be considered simultaneously avoiding overly pessimistic designs. Design techniques which reduce the variation of design parameters avoid over design and increase parametric yield.

Whereas tree topologies have been applied due to their minimal wire length, the application of generic routing graphs provides multiple paths to specific sinks. Multiple paths from source to sink increase the robustness against open defects and smoothes the effect of variation. New design techniques applying loops in VLSI wiring networks are the topic of this abstract. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hybrid neural network shock absorber model
Authors: Pracny Vladislav , Meywerk Martin
Published: September 2008

A hybrid neural network model is presented and described. The model is composed of a mechanical and thermodynamical part. The mechanical part is described by Akima spline in combination with a feed‐forward neural network, while in the case of the thermodynamic part differential equation of dissipative heating is formulated. The interface between both part is provided by the neural network. To identify a proper parameter set of the hybrid model a shock absorber of a middle class passenger car is measured on a servo‐hydraulic testing machine. As an excitation a stochastic signal with a predefined power spectral density (PSD) is used. Subsequently the hybrid shock absorber is implemented into a full vehicle model in ADAMS/Car to test its numerical performance and influence on the vertical vehicle dynamics. As reference a standard spline shock absorber model is taken. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A contribution to the modeling of metal foams on the mesoscale
Authors: Schwarzer Daniel , Gatouillat Sebastien , Proppe Carsten
Published: September 2008

Due to their useful properties in lightweight construction and due to their excellent behavior in energy absorption for example in crash mechanics, metal foams became an interesting, often utilized and investigated material. For the determination of the mechanical properties of foams without the help of expensive experiments, a way for computing these properties is searched. The problem in doing so is that foams can be composed out of randomly distributed edges and faces with varying thickness and of other inhomogeneities on the mesoscale like imperfections. The goal in this paper is, to investigate the influence of these irregularities on the mechanical, linear elastic properties of a metal foam on the macroscale and to determine the size of a representative volume element, for which the irregularities on the mesoscale do not have a great influence on the linear elastic properties. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analytical determination of residual stresses in a butt‐weld of two thin rectangular plates
Authors: Tokovyy Yuriy V. , Ma Chien‐Ching
Published: September 2008

Based upon the direct integration method, the technique for analysis of residual stresses in a thin rectangular plate consisting of two butt‐welded plates is presented. The material of plate is assumed to be elastic‐plastic. The welded joint is modeled by a locally distributed field of longitudinal and transversal residual strains. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Non‐invasive tension time index in relation to severity of disease in children with cystic fibrosis
Authors: Hahn Andreas , Ankermann Tobias , Claass Andreas , Mann Marion , Lindemann Hermann , Neubauer Bernd A.
Published: September 2008

The non‐invasive tension‐time index of the inspiratory muscles at rest (TTMUS) can be used for assessing respiratory muscle function in children with cystic fibrosis (CF). This study aimed to investigate how TTMUS becomes altered with increasing pulmonary impairment, and which factors determine TTMUS changes in CF. We assessed TTMUS in 47 patients with stable CF ranging in age from 9 to 26 years and in 47 controls of same age and gender. Pulmonary impairment was assessed by the pulmonary function score (PFS) according to Cropp (PFS 0–2 = no, 3–7 = mild, 8–12 = moderate, and 13–18 = severe dysfunction). Median TTMUS was significantly higher in the entire CF‐group than in controls ((0.112 (0.079–0.174) vs. 0.07 (0.052–0.094), P < 0.001)). It was nearly identical in CF‐patients without (0.079 (0.056–0.114)) and mild (0.080 (0.059–0.128)) pulmonary dysfunction. It was non‐significantly higher in subjects with moderate (0.118 (0.103–0.173)) and grossly elevated in individuals with severe (0.232 (0.211–0.31), P < 0.001)) respiratory impairment when compared to the other PFS‐groups. TTMUS was significantly related to percent predicted airway resistance (Raw%pred) (r = 0.60, P < 0.001), percent predicted Forced Expiratory Volume in 1 sec (r = −0.49, P < 0.001), percent predicted Vital Capacity (−0.57, P < 0.001), Functional Residual Capacity in percent Total Lung Capacity (r = 0.42, P = 0.003), and transcutaneous oxygen saturation (r = −0.49, P < 0.001). By contrast, Raw%pred was the only variable that had a significant effect on TTMUS (P = 0.01), when a multivariate logistic regression was applied, using the median of the entire CF‐cohort to dichotomise TTMUS. These findings suggest that subjects with stable CF and severe pulmonary dysfunction are prone to respiratory muscle fatigue, and that airway obstruction is an important factor contributing to the increase of TTMUS in CF. Regular determination of TTMUS may be clinically useful during course of disease, and may aid the decision to institute therapies like respiratory muscle training or non‐invasive intermittent ventilation. Pediatr Pulmonol. 2008; 43:973–981. © 2008 Wiley‐Liss, Inc.
The origin of reduced fill factors of emitter‐wrap‐through‐solar cells
Authors: Ulzhöfer Christian , Hermann Sonja , Harder Nils‐Peter , Altermatt Pietro P. , Brendel Rolf
Published: September 2008

Low fill factors generally limit the efficiency of emitter‐wrap‐through (EWT) solar cells. Until now, a conventional series resistance limitation along the laser‐drilled EWT vias has usually been assumed to be responsible for this effect. We demonstrate that the characteristic fill factor loss is caused by a crucial change in the diffusion currents inside the base, which are influenced by the conductivity along the laser‐drilled EWT vias. In addition, we show that the EWT via conductivity influences the fill factor loss caused by an iron contaminated base. This result affects the proposition that the EWT design is suitable for multicrystalline silicon in which interstitial iron is known to be the main contaminant. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrocaloric effect in antiferroelectric PbZrO3 thin films
Authors: Parui Jayanta , Krupanidhi S. B.
Published: September 2008

Antiferroelectric PbZrO3 thin films have been deposited on Pt(111)/Ti/SiO2/Si substrate by polymer modified sol–gel route. Temperature dependent P –E hysteresis loops have been measured at 51 MV/m within a temperature range of 40 °C to 330 °C. The maximum electrocaloric effect ∼0.224 × 10–6 K mV–1 has been observed near the dielectric phase transition temperature (235 °C) of the thin films. The electrocaloric effect and its strong temperature dependence have been attributed to nearly first‐order phase transition. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Site modelling methods for detecting hydrologic alteration of flood frequency and flood duration in the floodplain below the carlyle dam, lower Kaskaskia River, Illinois, USA
Authors: Romano Susan P. , Baer Sara G. , Zaczek James J. , Williard Karl W. J.
Published: September 2008

Reports concerning the influence of dams on river hydrology vary among researchers, interest groups and government agencies. These often contradicting statements may occur because changes in hydrology caused by dams are distinct for each dam and river watershed. The objective of this research was to use site specific techniques to determine if the 1967 installation of the Carlyle Dam, lower Kaskaskia River, Illinois, altered flood frequency and duration within the forested floodplain located below the dam. Results indicated a decrease in flood duration and frequency, and a decrease in annual flood frequency variation at a site 6.4 km below the dam. Pre‐dam versus post‐dam differences in flood frequency and duration at the site 32.2 km below the dam were related to climate rather than dam effects. Although dam impacts are a concern, this research shows that distance downstream from the dam and downstream tributary and watershed characteristics should be considered before assuming that the dam has changed hydrologic parameters for portions of rivers. This research also indicates that areas of the lower Kaskaskia River may still maintain hydrologic ecological integrity, and could be targeted for restoration and adaptive management purposes. Hydrologic modelling combined with river gage and on‐site well measurement techniques presented in this study could provide detailed flood frequency and duration information for land use, sociological and geomorphological questions in focus areas within river floodplains. Copyright © 2008 John Wiley & Sons, Ltd.
Improving the performance and functionality of Mondrian open‐source OLAP systems
Authors: Sendín‐Raña Pablo , González‐Castaño Francisco J. , Pérez‐Barros Enrique , Rodríguez‐Hernández Pedro S. , Gil‐Castiñeira Felipe , Pousada‐Carballo José M.
Published: September 2008

For a long time, the design of relational databases has focused on the optimization of atomic transactions (insert, select, update or delete). Currently, relational databases store tactical information of data warehouses, mainly for select‐like operations. However, the database paradigm has evolved, and nowadays on‐line analytical processing (OLAP) systems handle strategic information for further analysis. These systems enable fast, interactive and consistent information analysis of data warehouses, including shared calculations and allocations. OLAP and data warehouses jointly allow multidimensional data views, turning raw data into knowledge. OLAP allows ‘slice and dice’ navigation and a top‐down perspective of data hierarchies. In this paper, we describe our experience in the migration from a large relational database management system to an OLAP system on top of a relational layer (the data warehouse), and the resulting contributions in open‐source ROLAP optimization. Existing open‐source ROLAP technologies rely on summarized tables with materialized aggregate views to improve system performance (in terms of response time). The design and maintenance of those tables are cumbersome. Instead, we intensively exploit cache memory, where key data reside, yielding low response times. A cold start process brings summarized data from the relational database to cache memory, subsequently reducing the response time. We ensure concurrent access to the summarized data, as well as consistency when the relational database updates data. We also improve the OLAP functionality, by providing new features for automating the creation of calculated members. This makes it possible to define new measures on the fly using virtual dimensions, without re‐designing the multidimensional cube. We have chosen the XML/Ade factostandard for service provision. Copyright © 2008 John Wiley & Sons, Ltd.
On the problems of symbol‐spaced tapped‐delay‐line models for WSSUS channels
Authors: Guti Carlos A. , Cabrera‐Bean Margarita , Pätzold Matthias
Published: September 2008

This paper analyzes the validity and statistical behavior of symbol‐spaced tapped‐delay‐line (SSTDL) models for wide‐sense stationary uncorrelated scattering (WSSUS) mobile radio channels. SSTDL models are obtained by sampling the channel impulse response (CIR) in delay domain at a rate equal to the reciprocal of the symbol duration. They were proposed more than four decades ago as canonical channel models for band‐limited time‐variant linear (TVL) systems, and are nowadays widely in use for assessing the performance of several wireless communication systems. The applicability of these tapped‐delay‐line (TDL) models seems to be unquestionable, as they were developed in the framework of the sampling theorem. Nonetheless, we show here that SSTDL models should be used with care to model WSSUS channels, because the channel's uncorrelated scattering (US) condition might easily be violated. Furthermore, we show that SSTDL models suffer from strong limitations in emulating the channel frequency correlation function (FCF). This drawback leads to an inaccurate performance evaluation of wireless communication systems sensitive to the FCF. To cope with this problem, we present a simple solution by doubling the channel's sampling rate. The benefits of this solution are demonstrated with some exemplary simulation results. Copyright © 2008 John Wiley & Sons, Ltd.
l‐2‐Hydroxyglutaric aciduria: Clinical and molecular study in three Tunisian families. Identification of a new mutation and inter‐familial phenotype variability
Authors: Larnaout A. , Amouri R. , Kefi M. , Hentati F.
Published: September 2008

We report clinical and molecular studies in three unrelated Tunisian families containing seven patients with L2HGA. Although the age of onset is similar in all these patients at nearly 6 years, they progressively developed peculiar clinical phenotypes different from family to family. The three patients of family 1 showed mental retardation, epilepsy, cerebellar ataxia and pyramidal and pseudobulbar syndromes. The two patients of family 2 showed mental retardation and parkinsonism especially extrapyramidal stiffness, dystonia and myoclonus. The two patients of family 3 showed an intermediate phenotype; they share some clinical signs of the patients of family 1 (epilepsy, pyramidal and extrapyramidal syndromes) and some clinical signs of the patients of family 2 (extrapyramidal stiffness and dystonia). Molecular study identified a novel homozygous c.185C > A, p.A62D mutation on the L2HGDH gene in families 1 and 3 and the already known homozygous c.241A > G, p.K81E mutation in family 2. We suppose that the type of mutation in the L2HGDH gene does not play a complete role in the inter‐familial phenotype variability. Disturbance of other unknown metabolic pathways related to L2HGA may contribute to this phenomenon.
Standardization of a Surgical Site Precleansing Technique for Vascular Patients
Authors: Grelle Kelli , Linker Laura , Maninang Jennifer , Bruce Susan , Vish Nancy , Sample Shirley
Published: September 2008

SURGICAL SITE INFECTION (SSI) is a serious complication that can increase hospital costs and length of stay and may be life threatening.

THE PREOPERATIVE CHLORHEXIDINE shower is widely recommended to decrease SSI risk, although standardized guidelines for this practice and supporting clinical evidence are lacking.

BECAUSE VASCULAR PATIENTS often have comorbidities that hinder preoperative showering, OR nurses at a specialty hospital in Dallas, Texas, developed and implemented an intraoperative surgical site precleansing technique as standard practice for patients undergoing procedures involving the axilla or groin. AORN J 88 (August 2008) 261–265. © AORN, Inc, 2008.
Physiological levels of insulin and IGF‐1 synergistically enhance the differentiation of mesenteric adipocytes.
Authors: Sato Takashige , Nagafuku Masakazu , Shimizu Kyoko , Taira Toshio , Igarashi Yasuyuki , Inokuchi Jin‐ichi
Published: September 2008

Visceral adipose tissue, particularly mesenteric adipose tissue, is important in the pathogenesis of metabolic syndrome. Here, we present a physiologically relevant differentiation system of rat mesenteric‐stromal vascular cells (mSVC) to mesenteric‐visceral adipocytes (mVAC). We optimized the insulin concentration at levels comparable to thosein vivo(∼0.85 ng/ml) by including physiological concentrations of IGF‐1. We found that the insulin‐like growth factor (IGF‐1) and insulin worked synergistically, since IGF‐1 alone could induce CCAAT/enhancer binding protein alpha (C/EBPα) and adipocyte lipid binding protein (aP2) mRNA expression but not lipid droplet accumulation associated with maturation. Using real‐time PCR analyses on 180 adipocyte‐related genes, we identified a dramatic effect by IGF‐1 plus insulin. We also demonstrated the state of insulin resistance at pathologically high insulin concentrations. This culture system will contribute to understanding the physiological differentiation process and the patho/physiology of mVAC.
Dynamic determination of Ox‐LDL‐induced oxidative/nitrosative stress in single macrophage by using fluorescent probes
Authors: Deng Tongle , Xu Kedi , Zhang Le , Zheng Xiaoxiang
Published: September 2008

Increased oxidative/nitrosative stress, resulting from generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) appears to play an important role in the inflammatory responses to atherosclerosis. By using MitoTracker Orange CM‐H2TMRos, CM‐H2DCFDA (DCF‐DA), Dihydrorhodamine 123 (DHR123), DAF‐FM, Dihydroethidium (DHE) and JC‐1 alone or in all combinations of red and green probes, the present study was designed to monitor the ROS and RNS generation in acute exposure of single monocyte U937‐derived macrophage to oxidized low density lipoprotein (Ox‐LDL). Acute Ox‐LDL (100 μg/ml) treatment increased time‐dependently production of intracellular nitric oxide (NO), superoxide (O2−), hydrogen peroxide (H2O2) and peroxynitrite (ONOO−), and decreased mitochondrial membrane potential (Δ∍) in single cell. Pretreatment of aminoguanidine (an inhibitor of inducible nitric oxide synthase (iNOS), 10 μM) and vitamin C (an antioxidant agent, 100 μM) for 2 h, reduced significantly the Ox‐LDL‐induced increase of NO and O2−, and vitamin C completely inhibited increase of intracellular NO and O2−. In contrast to aminoguanidine, Vitamin C pretreatment significantly prevented Ox‐LDL‐induced overproduction of NO and O2−(P< 0.01), indicating that antioxidant may be more effective in therapeutic application than iNOS inhibitor in dysfunction of ROS/RNS. By demonstrating a complex imbalance of ROS/RNS via fluorescent probes in acute exposure of single cell to Ox‐LDL, oxidative/nitrosative stress might be more detected in the early atherosclerotic lesions.
Characterization and hepatogenic differentiation of mesenchymal stem cells from human amniotic fluid and human bone marrow: A comparative study
Authors: Zheng Yu‐Bao , Gao Zhi‐Liang , Xie Chan , Zhu Hai‐Peng , Peng Liang , Chen Jun‐Hong , Chong Yu Tian
Published: September 2008

Since stem cells can differentiate into hepatocyte, stem cell‐based therapy becomes a potential alternative treatment for terminal liver diseases. However, an appropriate source of human mesenchymal stem cells (hMSCs) for hepatocytes has not yet been clearly elucidated. The aim of the present study was to investigate the in vitro biological characterization and hepatic differentiation potential of human amniotic fluid‐derived mesenchymal stem cells (AF‐hMSCs) and human bone marrow‐derived mesenchymal stem cells (BM‐hMSCs). Our results show that AF‐hMSCs possess higher proliferation and self‐renewal capacity than BM‐hMSCs. Cytogenetic studies indicate that AF‐hMSCs are as genetically stabile as BM‐hMSCs. Following incubation with specific hepatogenic agents, AF‐hMSCs showed a higher hepatic differentiation potential than BM‐hMSCs. Expression of several liver‐specific markers was significantly greater in AF‐hMSCs than in BM‐hMSCs, as shown by real time RT‐PCR and immunofluorescence (IF). In conclusion, AF‐hMSCs possess superior potential for hepatic differentiation, making them more suitable for diverse terminal liver diseases.
Effect of polyamine deficiency on proteins involved in Okazaki fragment maturation
Authors: Johansson Veronica M. , Miniotis Maria Falck , Hegardt Cecilia , Jönsson Göran , Staaf Johan , Berntsson Pia S.H. , Oredsson Stina M. , Alm Kersti
Published: September 2008

Polyamine depletion causes S phase prolongation, and earlier studies indicate that the elongation step of DNA replication is affected. This led us to investigate the effects of polyamine depletion on enzymes crucial for Okazaki fragment maturation in the two breast cancer cell lines MCF‐7 and L56Br‐C1. In MCF‐7 cells, treatment withN1,N11‐diethylnorspermine (DENSPM) causes S phase prolongation. In L56Br‐C1 cells the prolongation is followed by massive apoptosis. In the present study we show that L56Br‐C1 cells have substantially lower basal expressions of two Okazaki fragment maturation key proteins, DNA ligase I and FEN1, than MCF‐7 cells. Thus, these two proteins might be promising markers for prediction of polyamine depletion sensitivity, something that can be useful for cancer treatment with polyamine analogues. DENSPM treatment affects the cellular distribution of FEN1 in L56Br‐C1 cells, but not in MCF‐7 cells, implying that FEN1 is affected by or involved in DENSPM‐induced apoptosis.
Unique membrane‐interacting properties of the immunostimulatory cationic peptide KLKL5KLK (KLK)
Authors: Aichinger Michael C. , Ortbauer Martina , Reipert Siegfried , Zauner Wolfgang , Bogner Péter , Froschauer Elisabeth , Nowikovsky Karin , Lingnau Karen , von Gabain Alexander , Schweyen Rudolf , Henics Tamás
Published: September 2008

We have monitored the effects of KLKL5KLK (KLK), a derivative of a natural cationic antimicrobial peptide (CAP) on isolated membrane vesicles, and investigated the partition of the peptide within these structures. KLK readily interacted with fluorescent dyes entrapped in the vesicles without apparent pore formation. Fractionation of vesicles revealed KLK predominantly in the membrane. Peptide‐treated vesicles appeared with generally disorganized bilayers. While KLK showed no effect on osmotic resistance of human erythrocytes, dramatic decrease in core and surface membrane fluidity was observed in peptide‐treated erythrocyte ghosts as measured by fluorescence anisotropy. Finally, CD spectroscopy revealed lipid‐induced random coil to β‐sheet and β‐sheet to α‐helix conformational transitions of KLK. Together with the oligonucleotide oligo‐d(IC)13 [ODN1a], KLK functions as a novel adjuvant, termed IC31™. Among other immunological effects, KLK appears to facilitate the uptake and delivery of ODN1a into cellular compartments, but the nature of KLK's interaction with the cell surface and other membrane‐bordered compartments remains unknown. Our results suggest a profound membrane interacting property of KLK that might contribute to the immunostimulatory activities of IC31™.
Differences in the sensitivity of behavioural measures of pain to the selectivity of cyclo‐oxygenase inhibitors
Authors: Huntjens Dymphy R.H. , Spalding David J.M. , Danhof Meindert , Pasqua Oscar E. Della
Published: September 2008

Objectives:Freund's complete adjuvant (FCA) is an animal model of inflammatory pain commonly used in the screening of COX‐inhibitors. However, there is little understanding of how behavioural measures of the anti‐inflammatory effect in the FCA model correlate to differences in mechanism of action and whether such endpoints equally reflect drug activity in humans. In the current investigation we evaluate the time course of the analgesic effect for different endpoints after treatment with drugs with varying degrees of selectivity for COX‐1 and COX‐2. We also assess prostaglandin (PGE2) and thromboxane (TXB2) inhibition to establish the correlation between behavioural measures and the degree of selectivity for COX‐1 and COX‐2.

Methods:Sprague–Dawley rats were treated with FCA by intra‐plantar injection. On post‐inoculation day (PID) 7, rats received a single oral dose of naproxen, diclofenac, ketorolac or rofecoxib. Drug treatment continued until PID 21. A control group received placebo only. Behavioural endpoints for inflammatory pain and blood samples for biomarkers were obtained at various time points before and after dosing to characterise the time course of drug effect and disease progression.

Results:COX‐inhibitors showed no effect on the dynamic plantar test. In contrast, full analgesia was observed after drug administration for weight bearing capacity (WBC) and paw pressure (PP), with varying duration of the effect for each of the endpoints. No tolerance to drug effect was observed up to 14 days of chronic treatment. Rofecoxib showed an increase in baseline pain threshold values after chronic treatment, which may be related to its pharmacokinetic characteristics.

Conclusions:Changes in paw pressure threshold seem to best reflect the anti‐hyperalgesic properties of COX‐inhibitors with enough sensitivity to enable estimation of the dose‐exposure‐response curve.
The impact of stressful life events on risk of relapse in women with multiple sclerosis: A prospective study
Authors: Mitsonis Charalampos I. , Zervas Iannis M. , Mitropoulos Panagiotis A. , Dimopoulos Nikolaos P. , Soldatos Constantin R. , Potagas Constantin M. , Sfagos Constantin A.
Published: September 2008

Purpose

The aims of this study were first, to examine the general relation between stressful life events (SLEs) and clinical relapses in women with multiple sclerosis (MS) and second, to investigate the relations of the specific stressor attributes of duration, type, and severity on MS exacerbations.

Methods

Twenty six ambulating women with relapsing-remitting MS were followed-up for a mean of 56.3 weeks. Patients documented SLEs weekly in self report diaries which were then collected at regular pre-scheduled clinic visits every 4 weeks. SLEs were classified as short-term if they had subjectively no lasting effect and long-term if they had a subjectively felt psychological impact that lasted at least 10–14 days after the event. The severity of SLEs was determined using the Recent Life Change Questionnaire.

Results

Experiencing three or more SLEs, during a 4-week period, was associated with a 5-fold increase of MS relapse rate (95% CI 1.7–16.4, p = 0.003). The presence of at least one long-term SLE was associated with three times (95% CI 1.01–9.13, p < 0.05) the rate of MS exacerbation during the following 4 weeks. There was no significant association between the severity (95% CI 0.99–1.01, p > 0.05) or the type (χ2 = 7.29, df = 5, p > 0.05) of stressor and the risk for relapse.

Conclusion

Ambulatory women with relapsing-remitting MS who experience cumulative SLEs may be at a greater risk for relapse. Duration is the only stress attribute that seems to increase the risk for relapsing in contrast to stress type and stress severity that were not found to interact with MS exacerbation.
Oxidative demethylation of 3‐methylthymine and 3‐methyluracil in single‐stranded DNA and RNA by mouse and human FTO
Authors: Jia Guifang , Yang Cai-Guang , Yang Shangdong , Jian Xing , Yi Chengqi , Zhou Zhiqiang , He Chuan
Published: September 2008

The human obesity susceptibility gene, FTO, encodes a protein that is homologous to the DNA repair AlkB protein. The AlkB family proteins utilize iron(II), α‐ketoglutarate (α‐KG) and dioxygen to perform oxidative repair of alkylated nucleobases in DNA and RNA. We demonstrate here the oxidative demethylation of 3‐methylthymine (3‐meT) in single‐stranded DNA (ssDNA) and 3‐methyluracil (3‐meU) in single‐stranded RNA (ssRNA) by recombinant human FTO protein in vitro. Both human and mouse FTO proteins preferentially repair 3‐meT in ssDNA over other base lesions tested. They showed negligible activities against 3‐meT in double‐stranded DNA (dsDNA). In addition, these two proteins can catalyze the demethylation of 3‐meU in ssRNA with a slightly higher efficiency over that of 3‐meT in ssDNA, suggesting that methylated RNAs are the preferred substrates for FTO.
A conserved dibasic site is essential for correct processing of the peptide hormone AtRALF1 in Arabidopsis thaliana
Authors: Matos Juliana L. , Fiori Celso S. , Silva-Filho Marcio C. , Moura Daniel S.
Published: September 2008

Prohormone proteins in animals and yeast are typically processed at dibasic sites by convertases. Propeptide hormones are also found in plants but little is known about processing. We show for the first time that a dibasic site upstream of a plant peptide hormone, AtRALF1, is essential for processing. Overexpression of preproAtRALF1 causes semi‐dwarfism whereas overexpression of preproAtRALF1(R69A), the propeptide with a mutation in the dibasic site, shows a normal phenotype. RALF1(R69A) plants accumulate only the mutated proprotein and not the processed peptide. In vitro processing using microsomal fractions suggests that processing is carried out by a kexin‐like convertase.
The role of a conserved histidine residue in a pyruvate‐specific Class II aldolase
Authors: Wang Weijun , Seah Stephen Y.K.
Published: September 2008

Histidine 45 in HpaI was replaced with alanine (H45A) and glutamine (H45Q). In the aldol cleavage reaction, k
cat values were lowered by 78‐ and 2059‐fold while K
m values were increased by 100‐ and 42‐fold in H45A and H45Q, respectively, compared to the wild‐type enzyme. Both mutants displayed higher dissociation constants towards the metal cofactor, pyruvate and the transition state analogue, oxalate. Pyruvate proton exchange rates are consequently reduced in H45A and H45Q. pK
a for a catalytic base (6.5) is lost in the mutant enzymes and catalysis is dependent on hydroxide ions. The results show that histidine 45 is important for metal cofactor binding and for facilitating C4‐OH proton abstraction of the substrate in the reaction mechanism.
Feline panleukopenia virus, feline herpesvirus-1, and feline calicivirus antibody responses in seronegative specific pathogen-free cats after a single administration of two different modified live FVRCP vaccines
Authors: Lappin Michael R. , Veir Julia , Hawley Jennifer
Published: September 2008

Two groups of feline panleukopenia virus (FPV), feline calicivirus (FCV), and feline herpesvirus-1 (FHV-1) seronegative cats (five cats per group) were administered one of two modified live feline viral rhinotracheitis, calicivirus, and panleukopenia virus (FVRCP) vaccines and the serological responses to each agent were followed over 28 days. While all cats developed detectable FPV and FCV antibody titers; only two cats developed detectable FHV-1 antibody titers using the criteria described by the testing laboratory. For FPV and FHV-1, there were no differences in seroconversion rates between the cats that were administered the intranasal (IN) FVRCP vaccine and the cats that were administered the parenteral FVRCP vaccine on any day post-inoculation. For FCV, the cats that were administered the IN FVRCP vaccine were more likely to seroconvert on days 10 and 14 when compared to cats that were administered the parenteral FVRCP vaccine.
Orbital- and sub-orbital-scale climate impacts on vegetation of the western Mediterranean basin over the last 48,000 yr
Authors: Fletcher William J. , Sánchez Goñi Maria Fernanda
Published: September 2008

High-resolution pollen analysis of Alborán Sea core MD95-2043 provides a 48-ka continuous vegetation record that can be directly correlated with sea surface and deep-water changes. The reliability of this record is supported by comparison with that of Padul (Sierra Nevada, Spain). Marine Isotope Stage (MIS) 3 was characterised by fluctuations in Quercus forest cover in response to Dansgaard-Oeschger climate variability. MIS 2 was characterised by the dominance of semi-desert vegetation. Despite overall dry and cold conditions during MIS 2, Heinrich events (HEs) 2 and 1 were distinguished from the last glacial maximum by more intensely arid conditions. Taxon-specific vegetation responses to a tripartite climatic structure within the HEs are observed. In MIS 1, the Bölling-Allerød was marked by rapid afforestation, while a re-expansion of semi-desert environments occurred during the Younger Dryas. The maximum development of mixed Quercus forest occurred between 11.7 and 5.4 cal ka BP, with forest decline since 5.4 cal ka BP. On orbital timescales, a long-term expansion of semi-desert vegetation from MIS 3 into MIS 2 reflects global ice-volume trends, while Holocene arboreal decline reflects summer insolation decrease. The influence of precession on the amplitude of forest development and vegetation composition is also detected.
Does Legal Doctrine Matter? Unpacking Law and Policy Preferences on the U.S. Supreme Court
Authors: BAILEY MICHAEL A. , MALTZMAN FORREST
Published: September 2008

Judicial scholars often struggle to disentangle the effects of law and policy preferences on U.S. Supreme Court decision making. We employ a new approach to measuring the effect—if any—of the law on justices' decisions. We use positions taken on Supreme Court cases by members of Congress and presidents to identify policy components of voting. Doing so enables us to isolate the effects of three legal doctrines: adherence to precedent, judicial restraint, and a strict interpretation of the First Amendment's protection of speech clause. We find considerable evidence that legal factors play an important role in Supreme Court decision making. We also find that the effect of legal factors varies across justices.
Commentary on ‘Prebiotics, immune function, infection and inflammation: a review of the evidence’
Authors: Tuohy K. M.
Published: September 2008

There is a growing awareness that the gut microbiota and an appropriately functioning immune system play an important role in maintaining human health. Recent population statistics have highlighted some worrying trends, specifically that there is a growing burden of immunological disease in Western populations, that Western populations are ageing, and that obesity, with its strong inflammatory component, is reaching epidemic proportions.
The addition of high manganese to a copper-deficient diet further depresses copper status and growth of cattle
Authors: Hansen Stephanie L. , Ashwell Melissa S. , Legleiter Leon R. , Fry Robert S. , Lloyd Karen E. , Spears Jerry W.
Published: September 2008

A study was conducted evaluating the effect of long-term Cu deficiency, with or without high Mn, on growth, gene expression and Cu status of beef cattle. Twenty-one Angus calves were born to cows receiving one of the following treatments: (1) 10 mg supplemental Cu/kg DM (+Cu); (2) no supplemental Cu and 2 mg Mo/kg DM ( − Cu); (3) − Cu diet plus 500 mg supplemental Mn/kg DM ( − Cu+Mn). Calves were weaned at approximately 183 d of age and individually fed throughout the growing and finishing phases. Plasma Cu was lower (P < 0·01) in − Cu calves compared with +Cu calves while high dietary Mn further depressed (P < 0·01) plasma Cu in − Cu+Mn calvesv.− Cu calves. Liver Cu concentrations in +Cu calves were greater (P < 0·01) than in − Cu calves, with no differences between − Cu and − Cu+Mn calves. The daily body-weight gain of +Cu calves was greater (P < 0·01) than − Cu calves during the period from birth to weaning, but did not differ during the growing phase. − Cu+Mn calves gained less (P < 0·05) than − Cu calves during the growing phase. DM intake was lower (P < 0·01) in − Cu+Mn calvesv.− Cu calves, and did not differ among +Cu and − Cu calves. The relative gene expression of cytochrome c oxidase in the liver was lower (P < 0·05) in − Cu calves compared with +Cu or − Cu+Mn calves. In conclusion, feeding a Cu − deficient diet in combination with high Mn negatively affected the growth and Cu status of beef cattle.
Effects of a flaxseed-derived lignan supplement on C-reactive protein, IL-6 and retinol-binding protein 4 in type 2 diabetic patients
Authors: Pan An , Demark-Wahnefried Wendy , Ye Xingwang , Yu Zhijie , Li Huaixing , Qi Qibin , Sun Jianqin , Chen Yanqiu , Chen Xiafei , Liu Yong , Lin Xu
Published: September 2008

Elevated C-reactive protein (CRP), IL-6 and retinol-binding protein 4 (RBP4) levels are associated with insulin resistance and diabetes mellitus. Phytoestrogens (including lignans and isoflavones) may enhance the management of diabetes and are hypothesized to act through inflammation pathways. The present study explored the effects of flaxseed-derived lignan on inflammatory factors and RBP4 concentrations in type 2 diabetics, who have higher levels of these biomarkers. Seventy community-dwelling diabetic patients (twenty-six men and forty-four post-menopausal women) with mild hypercholesterolaemia completed a randomized, double-blind, placebo-controlled, cross-over trial of supplementation with flaxseed-derived lignan capsules (360 mg/d) or placebo for 12 weeks, separated by an 8-week wash-out period. The participants maintained their habitual diets and levels of physical activity. Baseline to follow-up concentrations of CRP increased significantly within the placebo group (1·42 (sem 0·19) v. 1·96 (sem 0·22) mg/l, P < 0·001), but were comparatively unchanged in the lignan-supplemented group (1·67 (sem 0·19) v. 1·90 (sem 0·26) mg/l, P = 0·94); a significant difference was observed between treatments ( − 0·45 (95 % CI − 0·76, − 0·08) mg/l, P = 0·021). This effect was confined to women (P = 0·016), but not observed in men (P = 0·49). No between-treatment differences were found with regard to IL-6 or RBP4; though IL-6 concentrations increased significantly from baseline to follow-up in both groups (P = 0·004 and P < 0·001 following lignan and placebo treatments, respectively). The study suggests that lignan might modulate CRP levels in type 2 diabetics. These results need to be confirmed by further large clinical trials of longer duration.
Virgin olive oil polyphenol hydroxytyrosol acetate inhibitsin vitroplatelet aggregation in human whole blood: comparison with hydroxytyrosol and acetylsalicylic acid
Authors: González Correa José Antonio , López-Villodres Juan Antonio , Asensi Rocío , Espartero José Luis , Rodríguez-Gutiérez Guillermo , De La Cruz José Pedro
Published: September 2008

Hydroxytyrosol acetate (HT-AC) is a polyphenol present in virgin olive oil (VOO) at a proportion similar to hydroxytyrosol (HT) (160–479 μmol/kg oil). The present study was designed to measure thein vitroplatelet antiaggregating activity of HT-AC in human whole blood, and compare this effect with that of HT and acetylsalicylic acid (ASA). The experiments were designed according to the standard procedure to investigate the activity of ASA. HT-AC and HT inhibited platelet aggregation induced by ADP, collagen or arachidonic acid in both whole blood and platelet-rich plasma (PRP). ASA and HT-AC had a greater effect in whole blood than in PRP when ADP or collagen was used as inducer. ASA and HT-AC had a greater effect in PRP+leucocytes than in PRP alone. All three compounds inhibited platelet thromboxane B2and leucocyte 6-keto-prostaglandin F1α(6-keto-PF1α) production. The thromboxane/6-keto-PGF1αinhibition ratio (as an indirect index of the prostanoid equilibrium) was 10·8 (se1) for HT-AC, 1·0 (se0·1) for HT and 3·3 (se0·2) for ASA. All three compounds stimulated nitric oxide production, although HT was a weaker effect. In our experiments only concentrations higher than 500 μm(HT) or 1 mm(HT-AC and ASA) inhibited 3-nitrotyrosine production. All three compounds inhibited the production of TNFα by leucocytes, with no significant differences between them. In quantitative terms HT-AC showed a greater antiplatelet aggregating activity than HT and a similar activity to that of ASA. This effect involved a decrease in platelet thromboxane synthesis and an increase in leucocyte nitric oxide production.
Milk composition of franciscana dolphin (Pontoporia blainvillei) from Rio Grande do Sul, southern Brazil
Authors: Caon Glauco , Secchi Eduardo Resende , Capp Edison , Kucharski Luiz Carlos
Published: September 2008

Milk is the only external energy source for mammals in their early stages of life. Its composition varies during lactation in baleen whales and pinnipeds, while only descriptive studies are available for odontocetes. The aim of this work was to identify the components of the milk of franciscana,Pontoporia blainvillei, from southern Brazil. Samples were manually collected from lactating females (N = 5) incidentally caught in the gill-net fishery. The amount of fat, protein, carbohydrate, mineral and trace metal content, and caloric value of the samples were estimated. Milk of the franciscana dolphin presented mean fat, protein and carbohydrate concentrations similar to those described for other coastal species. A significant increase in fat concentration was observed in winter months, with a higher energy density. Potassium was the mineral found in higher amounts. Zinc, mercury and copper were detected in low concentrations. Due to different habitat conditions along the species distribution, the presence of a highly seasonal reproductive period and inter-population genetic variability, studies on milk composition in other areas is recommended.
Partitioning of the Pelagos Sanctuary (north-western Mediterranean Sea) into hotspots and coldspots of cetacean distributions
Authors: Moulins Aurélie , Rosso Massimiliano , Ballardini Marco , Würtz Maurizio
Published: September 2008

This study used Monte Carlo methods to generate simulations that considered the effort distribution to determine the locations of significant aggregations of cetacean sightings inside the northern Pelagos Sanctuary (north-western Mediterranean Sea). For three years, monitoring has been conducted from five motor vessels covering about 30,050 km. The most frequently encountered species were the striped dolphinStenella coeruleoalbarepresenting 64.7% of all sightings, the fin whaleBalaenoptera physalus(17.0%), Cuvier's beaked whaleZiphius cavirostris(9.9%), Risso's dolphinGrampus griseus(4.3%) and the sperm whalePhyseter catodon(2.2%). Sightings' positions and effort coverage were distributed over a grid of 5′ longitude and 5′ latitude. Spatial concentrations of sightings were analysed according to the distribution of effort to identify ‘hotspots’ (locations where the species occurred at a significantly greater frequency than expected), and ‘coldspots’ (locations with a significantly lower frequency than expected). Most fin whale hotspots (14) were located on the bathyal plain between 2000 and 2500 m, four hotspots were around the 1000 m isobaths, and one is located close to the seamount off Genoa. Fin whale coldspots were mainly along the coast. Striped dolphin hotspots were widely distributed over two main areas, in waters with depths between 2000 and 2500 m and at the continental slope; coldspots for this species were also mainly along the coast in the northern part of the study area. Many hotspots were found in the Genoa Canyon, and hotspots of striped dolphins, Cuvier's beaked whales, sperm whales and Risso's dolphins overlapped in this region. Some of the hotspots of Cuvier's beaked whales were identified at the seamount in the study area, where no other species was sighted frequently. Risso's dolphin hotspots were mainly near the 1000 m isobath. For sperm whales, several hotspots were identified: three associated with steep slope features (such as canyons or the continental slope), and one was in the centre of the flat area of Pelagos where the depth is 2500 m. This study highlights the ecological importance of particular locations inside the Pelagos Sanctuary—locations that should be protected from anthropogenic degradations for marine mammal conservation.
Fatty acid characterization of lipid fractions from blubber biopsies of sperm whalesPhyseter macrocephaluslocated around the Azores
Authors: Walton M.J. , Silva M.A. , Magalhães S.M. , Prieto R. , Santos R.S.
Published: September 2008

Fatty acid profiles of blubber have been shown previously to provide information on stock structure and sex differences. Generally the predominant blubber lipid of marine mammal species is triacylglycerol (fatty acids linked to glycerol) and previous studies have focused on this lipid class. But in some species such as the sperm whales the predominant lipid is wax esters (fatty acids linked to fatty alcohols) although triacylglycerols are also present. In this study the fatty acids and fatty alcohols of these lipid classes were characterized and the fatty acid profiles compared in order to assess their potential to provide qualitative ecological data.

Biopsy samples were obtained from 40 whales found in seas around the Azores achipelago during the period 2002–2003. The samples contained about 10% lipid of which 70% was wax ester and 11% triacylglycerol. The fatty acids of the triacylglycerols and wax esters were respectively approximately 19% and 16% saturated, 74% and 80% monounsaturated and 5% and 3% polyunsaturated with the main contributors being 18:1n-9, 16:1n-7 and 16:0. The alcohols of the wax esters were mainly either saturated or monounsaturated with the main contributors being 18:1n-9 (40%) and 16:0 (22%). No statistically significant differences in profiles were found between different island groups, between sexes or between years of sampling. In future studies there would not appear to be any apparent benefits over total lipid in examining each of the fatty acid classes of sperm whale blubber separately.