bluuebunny/crossref_metadata_2025 huggingface dataset:
Image‐based calculation of perfusion and oxyhemoglobin saturation in skeletal muscle during submaximal isometric contractions
Authors: Elder Christopher P. , Cook Ryan N. , Chance Marti A. , Copenhaver Elizabeth A. , Damon Bruce M.
Published: May 2010

The relative oxygen saturation of hemoglobin and the rate of perfusion are important physiological quantities, particularly in organs such as skeletal muscle, in which oxygen delivery and use are tightly coupled. The purpose of this study was to demonstrate the image‐based calculation of the relative oxygen saturation of hemoglobin and quantification of perfusion in skeletal muscle during isometric contractions. This was accomplished by establishing an empirical relationship between the rate of radiofrequency‐reversible dephasing and near‐infrared spectroscopy–observed oxyhemoglobin saturation (relative oxygen saturation of hemoglobin) under conditions of arterial occlusion and constant blood volume. A calibration curve was generated and used to calculate the relative oxygen saturation of hemoglobin from radiofrequency‐reversible dephasing changes measured during contraction. Twelve young healthy subjects underwent 300 s of arterial occlusion and performed isometric contractions of the dorsiflexors at 30% of maximal contraction for 120 s. Muscle perfusion was quantified during contraction by arterial spin labeling and measures of muscle T1. Comparisons between the relative oxygen saturation of hemoglobin values predicted from radiofrequency‐reversible dephasing and that measured by near‐infrared spectroscopy revealed no differences between methods (P = 0.760). Muscle perfusion reached a value of 34.7 mL 100 g−1 min−1 during contraction. These measurements hold future promise in measuring muscle oxygen consumption in healthy and diseased skeletal muscle. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Bayesian estimation of changes in transverse relaxation rates
Authors: Walker‐Samuel Simon , Orton Matthew , McPhail Lesley D. , Boult Jessica K. R. , Box Gary , Eccles Suzanne A. , Robinson Simon P.
Published: May 2010

Although the biasing of
R*2 estimates by assuming magnitude MR data to be normally distributed has been described, the effect on changes in R*2 (ΔR*2), such as induced by a paramagnetic contrast agent, has not been reported. In this study, two versions of a novel Bayesian maximum a posteriori approach for estimating ΔR*2 are described and evaluated: one that assumes normally distributed data and the other, Rice‐distributed data. The approach enables the robust, voxelwise determination of the uncertainty in ΔR*2 estimates and provides a useful statistical framework for quantifying the probability that a pixel has been significantly enhanced. This technique was evaluated in vivo, using ultrasmall superparamagnetic iron oxide particles in orthotopic murine prostate tumors. It is shown that assuming magnitude data to be normally distributed causes ΔR*2 to be underestimated when signal‐to‐noise ratio is modest. However, the biasing effect is less than is found in R*2 estimates, implying that the simplifying assumption of normally distributed noise is more justifiable when evaluating ΔR*2 compared with when evaluating precontrast R*2 values. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
See‐Sedimente als Zeugen der Schadstoffbelastung
Authors: Bogdal Christian , Schmid Peter , Anselmetti Flavio S. , Scheringer Martin
Published: May 2010

Schadstoffmessungen in den Sedimenten von Seen ermöglichen es, die Eintragsgeschichte von Chemikalien zu rekonstruieren. In Gletscherseen steigt die Konzentration persistenter organischer Schadstoffe, die längst verboten sind.
Muscheln, Moos und Milchzähne bringen Schadstoffe ans Licht
Authors: Schmid‐Ruzicka Susanne
Published: May 2010

In den Alpen erfasst das österreichische Umweltbundesamt mit Bioindikatoren unter anderem persistente organische Schadstoffe.
Zeugnistag fürs Chemiestudium
Authors: von Ahn Jessica
Published: May 2010

Chemiestudenten sind mit der Situation an ihren Hochschulen zufrieden. Ein Großteil plant, erst nach der Promotion ins Berufsleben zu starten.
Organischen Kohlenstoff in Feststoffen messen
Authors: Hupach Sascha
Published: May 2010

Ein neues Verfahren macht feste Proben zu flüssigen Proben, um ihren Gehalt an organischem Kohlenstoff zu bestimmen. Es besteht aus drei Schritten: Einwiegen, Dispergieren und Messen.
Umfangreiches Programm trotz sinkender Teilnehmerzahlen
Authors: Terborg Lydia
Published: May 2010

Zur Pittcon in Orlando reisten zwar noch weniger Besucher an als im Jahr zuvor, das Programm konnte sich aber sehen lassen. Etwa 960 Unternehmen präsentierten ihre neuesten Analytikgeräte.
Analytical integrations in 3D BEM for elliptic problems: Evaluation and implementation
Authors: Salvadori A.
Published: May 2010

The present publication deals with 3D elliptic boundary value problems (potential, Stokes, elasticity) in the framework of linear, isotropic, and homogeneous materials. Numerical approximation of the unique solution is achieved by 3D boundary element methods (BEMs). Adopting polynomial test and shape functions of arbitrary degree on flat triangular discretizations, the closed form of integrals that are involved in the 3D BEMs is proposed and discussed. Analyses are performed for all operators (single layer, double layer, hypersingular). The Lebesgue integrals are solved working in a local coordinate system. For singular integrals, both a limit to the boundary as well as the finite part of Hadamard (Lectures on Cauchy's Problem in Linear Partial Differential Equations. Yale University Press: New Haven, CT, U.S.A., 1923) approach have been considered. Copyright © 2010 John Wiley & Sons, Ltd.
Finite deformation frictional mortar contact using a semi‐smooth Newton method with consistent linearization
Authors: Gitterle Markus , Popp Alexander , Gee Michael W. , Wall Wolfgang A.
Published: May 2010

A two‐dimensional, finite deformation frictional contact formulation with Coulomb's law is presented. The approach considers multibody contact and is based on a mortar formulation. The enforcement of contact constraints is realized with dual Lagrange multipliers. These alternative multiplier spaces are constructed in a way that the multipliers can easily be eliminated from the global system of equations by static condensation such that the system size does not increase. Friction kinematic variables are formulated in an objective way and enter non‐smooth complementarity functions for expressing the contact constraints. An active set strategy is derived by applying a semi‐smooth Newton method, which treats contact nonlinearities, material and geometrical nonlinearities in one single iterative scheme. By further carrying out a consistent linearization for both normal and frictional contact forces and constraints, a robust and highly efficient algorithm for linear and higher‐order (quadratic) interpolation is achieved. Efficiency of the proposed method and quality of results are demonstrated in several examples. Copyright © 2010 John Wiley & Sons, Ltd.
Coupled meshfree and fractal finite element method for mixed mode two‐dimensional crack problems
Authors: Rajesh K. N. , Rao B. N.
Published: May 2010

This paper presents a coupling technique for integrating the element‐free Galerkin method (EFGM) with the fractal finite element method (FFEM) for analyzing homogeneous, isotropic, and two‐dimensional linear‐elastic cracked structures subjected to mixed‐mode (modes I and II) loading conditions. FFEM is adopted for discretization of the domain close to the crack tip and EFGM is adopted in the rest of the domain. In the transition region interface elements are employed. The shape functions within interface elements which comprise both the EFG and the finite element (FE) shape functions, satisfies the consistency condition thus ensuring convergence of the proposed coupled EFGM–FFEM. The proposed method combines the best features of EFGM and FFEM, in the sense that no special enriched basis functions or no structured mesh with special FEs are necessary and no post‐processing (employing any path independent integrals) is needed to determine fracture parameters, such as stress‐intensity factors (SIFs) and T‐stress. The numerical results show that SIFs and T‐stress obtained using the proposed method are in excellent agreement with the reference solutions for the structural and crack geometries considered in the present study. Also, a parametric study is carried out to examine the effects of the integration order, the similarity ratio, the number of transformation terms, and the crack length to width ratio on the quality of the numerical solutions. A numerical example on mixed‐mode condition is presented to simulate crack propagation. As in the proposed coupled EFGM–FFEM at each increment during the crack propagation, the FFEM mesh (around the crack tip) is shifted as it is to the new updated position of the crack tip (such that FFEM mesh center coincides with the crack tip) and few meshless nodes are sprinkled in the location where the FFEM mesh was lying previously, crack‐propagation analysis can be dramatically simplified. Copyright © 2010 John Wiley & Sons, Ltd.
Twins in prehistory: The case from Olèrdola (Barcelona, Spain; s. IV II BC)
Authors: Crespo L. , Subirà M. E. , Ruiz J.
Published: May 2010

This paper details the discovery of two perinatal individuals interred simultaneously at the archaeological site of Olèrdola, Barcelona, Spain. Information from the excavation and from the subsequent anthropological study of the recovered skeletal and dental remains suggests that these individuals (OL–2000–8245 and OL–2000–8246) are the first documented case of twins in Iberian period. The possibility of a simultaneous perinatal twins burial at Olèrdola raises new questions concerning about the frequency of twins in prehistory and protohistory. Copyright © 2010 John Wiley & Sons, Ltd.
The association between preeclampsia and placental disruption induced by chorionic villous sampling
Authors: Farina Antonio , Hasegawa Junichi , Raffaelli Simonetta , Ceccarini Chiara , Rapacchia Giuseppina , Pittalis M. Carla , Brondelli Lorena , Righetti Francesca , Rizzo Nicola
Published: May 2010

Objectives

The objectives of this study were (1) to evaluate if the elevation of maternal serum α‐feto protein (MSAFP) and pregnancy‐associated placental protein‐A (PAPP‐A) in the maternal blood after chorionic villous sampling (CVS) is associated with a higher preeclampsia (PE) rate and (2) to verify the clinical utility of the analytes elevation for predicting PE.

Methods

A prospective study on 106 subjects who underwent CVS was performed. At the time of CVS, two blood samples were obtained for MSAFP and PAPP‐A dosage, the first just before the procedure, and the second one 30 min after the procedure. Cases with abnormal karyotype, major anomalies or preterm delivery were subsequently excluded. The ratio between the two samples was calculated as Σ (MSAFP or PAPP‐A post‐CVS/MSAFP or PAPP‐A pre‐CVS) and it was related to subsequent occurrence of PE.

Results

The rate of PE was 5.7% (6/106). Both MSAFP and PAPP‐A levels were higher after than before CVS (median ratio = 8.33 and 1.08, respectively). Cases developing PE had significantly higher MSAFP ratio (11.6 vs 7.4, p‐value = 0.04) and PAPP‐A ratio (1.13 vs 1.08, p‐value = 0.009) than those who did not develop PE. Receiver operating characteristic curve analysis showed that PAPP‐A ratio was a better predictor of subsequent PE than MSAFP ratio: at a fixed false positive rate of 10%, the detection rates for MSAFP and PAPP‐A ratios were 33 and 50%, respectively.

Conclusion

The elevation of MSAFP and PAPP‐A observed with CVS is associated with increased risk of subsequent PE. The ability of such increases to predict PE appears to be modest. Copyright © 2010 John Wiley & Sons, Ltd.
ABCD position statement on physical activity and exercise in diabetes
Authors: Nagi D , Gallen I
Published: May 2010

The Association of British Clinical Diabetologists (ABCD) recognises the key importance of exercise and physical activity in the management of diabetes. This position statement by the ABCD aims to help health professionals working in diabetes to familiarise themselves with the issues surrounding the management of type 1 and type 2 diabetes.

ABCD strongly supports that exercise and physical activity are key components of the initial and ongoing management of type 2 diabetes and can help to improve metabolic control and tackle cardiovascular risk factors. ABCD also believes that diabetes teams have an important role both in promotion of physical activity and in education of the key benefits to patients, carers and health professionals involved in the day to day management of this condition. ABCD also recognises that the issues in type 1 diabetes are very different and that, in this category of patients, the health benefits of exercise are not well documented – the issue is to help and support people to engage in physical activity or sports of their choice in a safe manner. This kind of support is not universally available at present and much needs to be done to achieve this. Copyright © 2010 John Wiley & Sons.
Recommending NSAIDs and paracetamol: A survey of New Zealand physiotherapists' knowledge and behaviours
Authors: Braund Rhiannon , Abbott J. Haxby
Published: May 2010

Background. Clinical guidelines recommend medications as first line treatment for many musculoskeletal injuries. As first line health professionals for musculoskeletal conditions, including sprains and strains, physiotherapists may be asked to recommend suitable medications. Currently recommending medications is outside of the physiotherapists scope of practice. However there is evidence that physiotherapists often do recommend medications, mostly simple analgesics and non‐steroidal anti‐inflammatory drugs (NSAIDs). Purpose. The aim of this study was to investigate the current knowledge and behaviour of New Zealand musculoskeletal physiotherapists regarding recommendation of non‐prescription medications for the treatment of musculoskeletal sprains and strains. Method. 2438 New Zealand physiotherapists were surveyed, of whom approximately 948 work in musculoskeletal physiotherapy. Results. Of 278 respondents (29.3% response rate), 213 (81.0%) sometimes or often recommend oral NSAIDs to patients, and 216 (82.1%) recommend oral paracetamol. Most respondents (225, 85.5%) report that they routinely provide information on potential side effects, 181 (68.8%) on potential risks. Many refer to a pharmacist, however 146 (55.5%) make recommendations on dose, and 119 (45.2%) recommend specific brand names. When asked what the risks associated with NSAIDs were, most respondents (>70%) were able to name at least gastrointestinal upset, ulcers or bleeding, while the proportion able to name respiratory, renal or allergic risks was lower (<31%). Conclusion. These data indicate that a large proportion of New Zealand musculoskeletal physiotherapists are practicing outside of the general scope of physiotherapy practice with regards recommending medicines to patients. While a large proportion have a good knowledge of potential side effects and risks, the knowledge is incomplete and inadequate for this practice. Copyright © 2010 John Wiley & Sons, Ltd.
The crystal structure of the Y140F mutant of ADP‐L‐glycero‐D‐manno‐heptose 6‐epimerase bound to ADP‐β‐D‐mannose suggests a one base mechanism
Authors: Kowatz Thomas , Morrison James P. , Tanner Martin E. , Naismith James H.
Published: May 2010

Bacteria synthesize a wide array of unusual carbohydrate molecules, which they use in a variety of ways. The carbohydrate L‐glycero‐D‐manno‐heptose is an important component of lipopolysaccharide and is synthesized in a complex series of enzymatic steps. One step involves the epimerization at the C6″ position converting ADP‐D‐glycero‐D‐manno‐heptose into ADP‐L‐glycero‐D‐manno‐heptose. The enzyme responsible is a member of the short chain dehydrogenase superfamily, known as ADP‐L‐glycero‐D‐manno‐heptose 6‐epimerase (AGME). The structure of the enzyme was known but the arrangement of the catalytic site with respect to the substrate is unclear. We now report the structure of AGME bound to a substrate mimic, ADP‐β‐D‐mannose, which has the same stereochemical configuration as the substrate. The complex identifies the key residues and allows mechanistic insight into this novel enzyme.
Indoleamine 2,3‐dioxygenase (IDO) activity influence tumor growth in the TRAMP prostate cancer model
Authors: Källberg Eva , Wikström Pernilla , Bergh Anders , Ivars Fredrik , Leanderson Tomas
Published: May 2010

BACKGROUND

Indoleamine 2,3‐dioxygenase (IDO) activity has been shown to be expressed in local lymph nodes and induce immune suppression of tumor immunity. Here we analyze the effect of IDO expression on prostate tumor growth using the transgenic adenocarcinoma of mouse prostate (TRAMP) animal model.

METHODS

Mice deficient in IDO expression were crossed to TRAMP mice and the time to the appearance of palpable tumors were measured. Immune histology was used to analyze the IDO expressing cells in tumors and in local lymph nodes. The levels of the substrate for IDO (tryptophane) and its product (kynurenine) was measured by HPLC.

RESULTS

We found that systemic IDO activity, determined as the kynurenine/tryptophan ratio in serum, correlated with the presence of palpable tumor. Immunohistological analysis showed increased numbers of IDO expressing cells in local lymph nodes. In tumors, IDO expression could be detected in the tumor stroma by both CD31+ and CD31− cells. Essentially no CD45+, IDO expressing cells could be detected in the tumors. The influence of IDO activity on tumor progression was analyzed by back‐crossing TRAMP mice with IDO−/− animals and J‐chain negative (J−/−) mice that have perturbed IDO activity. In both crosses a delayed tumor incidence was observed.

CONCLUSION

Our results argue for a role for IDO mediated immune suppression in the early stages of prostate cancer progression. However, since the intra‐tumor IDO expression in J−/− mice was indistinguishable from that of C57BL/6 animals the IDO expression in the tumor tissue appears to be irrelevant for TRAMP tumor incidence. Prostate 70: 1461–1470, 2010. © 2010 Wiley‐Liss, Inc.
Muscarinic receptors and their mRNAs in type 2 Goto‐Kakizaki diabetic rat prostate
Authors: Saito Motoaki , Kazuyama Emi , Shimizu Shogo , Dimitriadis Fotios , Kinoshita Yukako , Masuda Eiji , Yamada Shizuo , Satoh Keisuke
Published: May 2010

BACKGROUND

As increasing evidence is pointing towards the relationship between diabetes and benign prostatic hyperplasia/lower urinary tract symptoms, we investigated the pharmacological properties and gene expressions of the muscarinic receptors in type 2 diabetes rat prostate.

METHODS

Twelve‐ and 70‐week‐old male Goto‐Kakizaki (GK) rats and age‐matched male Wistar rats were used in this study. The densities of muscarinic receptors (Bmaxvalues) were determined by saturation studies with [3H]NMS ([N‐methyl‐3H] scopolamine methyl chloride) in the prostatic membrane particulates. The participation levels of M1, M2, and M3receptor protein and mRNA levels in the prostate were investigated by immunoblot analysis and real‐time polymerase chain reaction (PCR), respectively.

RESULTS

The Bmaxvalues in 12‐week‐old Wistar and GK, and in 70‐week‐old Wistar and GK rat prostates were 36.0 ± 2.8, 49.4 ± 11.4, 22.0 ± 2.2, and 47.0 ± 4.1 fmol/mg protein, respectively. However, there were no significant differences in the affinity constants between any groups. Immunoblot analysis showed the existence of significant amounts of M1, M2, and M3receptor subtypes in each rat prostate. According to real‐time PCR studies the rank order of expression levels of muscarinic receptors mRNA subtypes in the prostate were M3 > M2 > M1. In each receptor subtype in each group, diabetes induced up‐regulation of mRNAs while the advanced age of the rats was related with down‐regulation of mRNAs.

CONCLUSIONS

Our data indicated that type 2 diabetes induced up‐regulation and age‐related down‐regulation of the expressions of muscarinic receptors and their mRNAs in the rat prostate. Prostate 70: 1533–1539, 2010. © 2010 Wiley‐Liss, Inc.
Effect of high‐pressure food processing on the mass transfer properties of selected packaging materials
Authors: Galotto Maria Jose , Ulloa Pablo , Escobar Rodrigo , Guarda Abel , Gavara Rafael , Miltz Joseph
Published: May 2010

The effect of high‐pressure processing (HPP) on the total migration into distilled water and olive oil and on the barrier properties of four complex packaging materials were evaluated. The films were polyethylene/ethylene‐vinyl‐alcohol/polyethylene (PE/EVOH/PE), metallized polyester/polyethylene, polyester/polyethylene (PET/PE), and polypropylene‐SiOx (PPSiOx). Pouches made from these films were filled with food simulants, sealed and then processed at a pressure of 400 MPa for 30 min, at 20 or 60°C. Pouches kept at atmospheric pressure were used as controls. Prior to and after treatment, all films were evaluated for their barrier properties (oxygen transmission rate and water vapour transmission rate) and ‘Total’ migration into the two food simulants. In the case of water as the food stimulant, a low ‘Total’ migration was observed and even a lower one after the HPP treatment. In the case of oil as the food simulant, a higher ‘Total’ migration was found compared to the control as a result of damage to the structures during the HPP treatment. The gas permeability of the films increased after the HPP, compared to the control, due to damages in the structure caused during the treatment. The PET/PE film presented minimum changes in properties after HPP. Copyright © 2010 John Wiley & Sons, Ltd.
Assessment of technical and environmental performances of wheat‐based foams in thermal packaging applications
Authors: Wang Yong , Gao Yun‐Xin , Song Jim , Bonin Michael , Guo Miao , Murphy Richard
Published: May 2010

This paper presents an assessment of the technical and environmental performance of a wheat‐based foam (WBF) and bio‐composite for shipping chilled products. The thermal conductivity of the WBF was found to be higher than that of polyurethane foams commonly used in high‐value insulation packaging, but close to that of low‐density (expanded polystyrene) EPS foams and significantly lower than that of polyethylene (PE) foams, which are typically used in thermal packaging of foods. The insulation performance of a simple cool box constructed from both the WBF and EPS sandwich panels without the use of any refrigerant was studied experimentally. The comparison demonstrated that the performance of the WBF cool box was comparable to that of the EPS counterpart. Two industrial case studies were conducted on WBF cool boxes with refrigerants in comparison with PE or EPS counterparts. The WBF cool boxes had comparable thermal performance to the EPS and PE counterparts on the basis of identical foam thickness. The performance of the WBF cool boxes was also simulated with finite element (FE) modelling. Good agreement was achieved between experimental data and the FE prediction. The model was then used to assist cool box design. WBF cool boxes made from renewable raw materials are inherently biodegradable and may be used as an alternative to those based on polymer foams in thermal packaging applications. Life‐cycle assessment (LCA) was used to investigate environmental profiles of cool boxes made with WBF, EPS and PE foams. The WBF cool boxes offer substantially lower global warming and abiotic depletion potentials than equivalent cool boxes made from petrochemical foams. Copyright © 2010 John Wiley & Sons, Ltd.
Analytical description of a nocturnal low‐level jet
Authors: Shapiro Alan , Fedorovich Evgeni
Published: May 2010

An exact analytical solution of the equations of motion is presented for the Blackadar conceptual model of the nocturnal low‐level jet as an inertial oscillation arising from the sudden release of frictional constraint (near‐cessation of dry‐convective turbulent mixing) near sunset. The jet is modelled as a transient one‐dimensional boundary‐layer phenomenon, with the release of frictional constraint emulated by an impulsively reduced mixing coefficient (eddy viscosity). Prior to the reduction, the flow is in an equilibrium state described by the classical steady‐state Ekman solution. The dimensional parameters of the transient problem are the Coriolis parameter, the post‐ and pre‐sunset eddy viscosities, and an imposed pressure gradient force. The corresponding non‐dimensional problem is governed by a single parameter, the ratio of the post‐ and pre‐sunset mixing coefficients. The solution is obtained by the method of Laplace transforms. Copyright © 2010 Royal Meteorological Society
Desorption electrospray ionization mass spectrometric analysis of organophosphorus chemical warfare agents using ion mobility and tandem mass spectrometry
Authors: D'Agostino Paul A. , Chenier Claude L.
Published: May 2010

Desorption electrospray ionization mass spectrometry (DESI‐MS) has been applied to the direct analysis of sample media for target chemicals, including chemical warfare agents (CWA), without the need for additional sample handling. During the present study, solid‐phase microextraction (SPME) fibers were used to sample the headspace above five organophosphorus CWA, O‐isopropyl methylphosphonofluoridate (sarin, GB), O‐pinacolyl methylphosphonofluoridate (soman, GD), O‐ethyl N,N‐dimethyl phosphoramidocyanidate (tabun, GA), O‐cyclohexyl methylphosphonofluoridate (cyclohexyl sarin, GF) and O‐ethyl S‐2‐diisopropylaminoethyl methyl phosphonothiolate (VX) spiked into glass headspace sampling vials. Following sampling, the SPME fibers were introduced directly into a modified ESI source, enabling rapid and safe DESI of the toxic compounds. A SYNAPT HDMS™ instrument was used to acquire time‐aligned parallel (TAP) fragmentation data, which provided both ion mobility and MSn (n = 2 or 3) data useful for the confirmation of CWA. Unique ion mobility profiles were acquired for each compound and characteristic product ions of the ion mobility separated ions were produced in the Triwave™ transfer collision region. Up to six full scanning MSn spectra, containing the [M + H]+ ion and up to seven diagnostic product ions, were acquired for each CWA during SPME fiber analysis. A rapid screening approach, based on the developed methodology, was applied to several typical forensic media, including Dacron sampling swabs spiked with 5 µg of CWA. Background interference was minimal and the spiked CWA were readily identified within one minute on the basis of the acquired ion mobility and mass spectrometric data. Copyright © 2010 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
Characterization of protostane triterpenoids in Alisma orientalis by ultra‐performance liquid chromatography coupled with quadrupole time‐of‐flight mass spectrometry
Authors: Liu Xin , Li Song‐Lin , Zhou Yan , Song Jing‐Zheng , Zheng Yun‐Feng , Peng Guo‐Ping , Xu Hong‐Xi
Published: May 2010

A reliable and sensitive ultra‐performance liquid chromatography/quadrupole time‐of‐flight mass spectrometry (UPLC/Q‐TOF‐MS) method has been optimized and established for analysis of protostane triterpenoids in a commonly used traditional Chinese herbal medicine Alisma orientalis (Sam.) Juzep. The separation of crude extract of A. orientalis was achieved on a Waters ACQUITY HSS T3 column (100 mm × 2.1 mm, 1.8 µm) eluting with 0.1% (v/v) formic acid/acetonitrile. A total of 20 protostane triterpenoids including 19 known compounds and a new one were well separated within 7 min. The collision‐induced dissociation (CID) tandem mass spectrometric (MS/MS) fragmentation patterns of protostane triterpenoids was firstly reported in this study. The hydrogen rearrangement at the C‐23‐OH leads to dissociation of the bond between C‐23 and C‐24 in the protostane triterpenoid skeleton during the CID process. This dissociation was the characteristic CID fragmentation pathway of this class of triterpenoids, and was useful for further differentiation of some positional isomers which contain an acetyl unit on the C‐23 or C‐24 position. The identities of isolated compounds were identified by comparing their retention times and CID fragmentation behaviors with those of reference standards or tentatively assigned by matching the empirical molecular formulae with those reported in the literature. It is concluded that this newly established UPLC/Q‐TOF‐MS method is a powerful approach for structural elucidation of protostane triterpenoids isolated from A. orientalis. Copyright © 2010 John Wiley & Sons, Ltd.
The relationship between the electrospray ionization behaviour and biological activity of some phosphino Cu(I) complexes
Authors: Tisato Francesco , Refosco Fiorenzo , Porchia Marina , Tegoni Matteo , Gandin Valentina , Marzano Cristina , Pellei Maura , Papini Grazia , Lucato Lara , Seraglia Roberta , Traldi Pietro
Published: May 2010

Electrospray ionization mass spectrometry was usefully employed for the characterization of three phosphino copper(I) complexes of medicinal interest. This technique revealed that the original [CuL4]+ pro‐drugs (L = hydrophilic tertiary phosphine) underwent dissociation with production of coordinative unsaturated [CuL3]+ and [CuL2]+ species, which represented key intermediates for the activation of potential biological properties. The more favoured was the displacement of the ligands from the [CuL4]+ parent complex, the more favoured was in turn the possibility for the metal ion to directly interact with biological substrates, including pharmacological targets related to cancer proliferation. An inverse correlation between the stability and the cytotoxic activity of the three copper(I) complexes investigated has been clearly established. Copyright © 2010 John Wiley & Sons, Ltd.
Adaptive Naive Bayes method for masquerade detection
Authors: Dash Subrat Kumar , Reddy Krupa Sagar , Pujari Arun K.
Published: May 2010

Recently, researchers have proposed efficient detection mechanisms for masquerade attacks. Most of these techniques use machine learning methods to learn the behavioral patterns of users and to check if an observed behavior conforms to the learnt behavior of a user. Masquerade attack is detected when the observed behavior, reportedly of a specific user, does not match with the learnt pattern of this user's past data. A major shortcoming in this process is that the user may legitimately deviate temporarily from its past behavior. If the deviation is large and near‐permanent, it is desirable that such deviations are captured in a detection mechanism. We propose, in this paper, a method that takes into consideration this aspect of user behavior while detecting masquerade attacks. Our scheme is based on the premise that the commands used by a legitimate user or an attacker may differ from the trained signature. But the deviation of the legitimate user is momentary whereas that of an attacker persists longer. By introducing this novel concept in the detection mechanism, the performance improves. We show this empirically using several benchmark datasets. Copyright © 2010 John Wiley & Sons, Ltd.
Protecting the integrity of trusted applications in mobile phone systems
Authors: Muthukumaran Divya , Schiffman Joshua , Hassan Mohamed , Sawani Anuj , Rao Vikhyath , Jaeger Trent
Published: May 2010

Mobile phones have evolved into indispensable devices that run many exciting applications that users can download from phone vendor's application stores. However, as it is not practical to fully vet all application code, users may download malware‐infected applications, which may steal or modify security‐critical data. In this paper, we propose a security architecture for phone systems that protects trusted applications from such downloaded code. Our architecture uses reference monitors in the operating system and user‐space services to enforce mandatory access control policies that express an approximation of Clark—Wilson integrity. In addition, we show how to justify the integrity of mobile phone applications by using the Policy Reduced Integrity Measurement Architecture (PRIMA), which enables a remote party to verify the integrity of applications running on a phone. We have implemented a prototype on the Openmoko Linux Platform, using an SELinux kernel with a PRIMA module and user‐space services that leverage the SELinux user‐level policy server. We find that the performance of enforcement and integrity measurement is satisfactory, and the SELinux reference policy can be reduced in size by 90% (although more reduction should be possible), enabling practical system integrity with a desirable usability model. Copyright © 2010 John Wiley & Sons, Ltd.
A formal model of trust for calculating the quality of X.509 certificate
Authors: Samer Wazan Ahmad , Romain Laborde , Francois Barrere , AbdelMalek Benzekri
Published: May 2010

The growing number of Public Key Infrastructure (PKI) and the increasing number of situations where partners of a transaction may carry certificates signed by different certification authority (CA) points out the problematic of trust between the different CAs. Several trust models, like the hierarchy model, cross‐certification model, and bridge CA model were proposed in order to establish and extend the domain of trust of relying parties (RP). However, each model has disadvantages and especially the scalability in large open networks like Internet. In this paper, we provide users with quantitative information of the confidence a relying party can have about a certificate. We call this information quality of certificate (QoCER). QoCER depends on two parameters which are the quality of procedures announced in the certificate policy (CP) and the quality of CA (QoCA) that represents the evaluation of the CA commitment to its policy. QoCA is calculated based on the recommendation of different actors (audit agency, RP, etc.). QoCER is balanced by another information that represents the confidence on QoCA calculation. We present a formal model of trust to calculate these values. Copyright © 2010 John Wiley & Sons, Ltd.
Photoemission study of methanol decomposition on Pt/Ni(111) surface alloy
Authors: Veltruská K. , Cabala M. , Libra J. , Skála T. , Tsud N. , Matolín V.
Published: May 2010

Platinum shows excellent catalytic activity in electrochemical oxidation of methanol. It is widely used in direct methanol fuel cells, but it is readily poisoned by CO‐like intermediates generated in methanol activation process. To increase Pt CO tolerance, oxophilic metals such as Ru or Ni are incorporated into Pt.

In our model study we present results of the adsorption and decomposition of methanol on a Pt‐Ni ordered surface alloy prepared by Pt evaporation on Ni(111) surface, examined by conventional and synchrotron radiation XPS. Methanol adsorbed at low temperature formed adsorbate multilayers, which were consecutively desorbed upon heating to 600 K. Reaction intermediates arising during desorption were measured. Reaction pathways are discussed and compared with those obtained on a clean Ni(111) single crystal. Copyright © 2010 John Wiley & Sons, Ltd.
Optimal software maintenance policy considering unavailable time
Authors: Xiong Cheng‐Jie , Xie Min , Ng Szu‐Hui
Published: May 2010

With the enhancement of hardware and software engineering, the effectiveness and correctness of software is less and less doubted and customers are more aware about whether software services are available or not when needed. Software maintenance is one of the main reasons that make software unavailable and it is often very expensive to perform maintenance tasks. Common approaches of studying software maintenance are to consider it as a static by‐product of software operation and only the maintenance cost is covered. In this paper, software maintenance policies are studied with the consideration of unavailable service time. A non‐homogeneous continuous Markov chain is adopted for modeling the software operation and maintenance process, and the cost of software unavailability that is brought in by software maintenance is investigated and analyzed for searching the optimal maintenance policy, which aims at minimizing the average maintenance time cost. The optimality of our proposed policy is shown and checked by numerical examples with discussions of its possible application perspectives. Copyright © 2010 John Wiley & Sons, Ltd.
Aussteifung und Stabilisierung von Bauteilen und Tragwerken durch Sandwichelemente
Authors: Käpplein Saskia , Misiek Thomas , Ummenhofer Thomas
Published: May 2010

Werden die systembedingten Besonderheiten beachtet, die sich aus dem hohen Vorfertigungsgrad der Bauelemente ergeben, lässt sich die hohe Steifigkeit von Sandwichelementen zur Aussteifung oder Stabilisierung nutzen. Der Stand der Technik in der Ermittlung der Steifigkeit und Tragfähigkeit von Sandwichelementen bei Beanspruchung als Scheibe wird vorgestellt. Der dominierende Einfluss der Verbindungen wird erläutert sowie aktuelle Entwicklungstendenzen aufgezeigt.

Bracing and stabilisation by sandwich panels. The high in‐plane stiffness of sandwich panels can be taken into account for bracing (diaphragm action) or stabilisation (beams, columns) if the characteristics of such systems are taken into account. These characteristics are determined by the high degree of pre‐fabrication. The state of the art in the calculation of the stiffness and the load‐bearing capacity of sandwich panels under in‐plane loading is introduced. The dominating influence of the fixings is explained. Current development trends are identified.
Gekrümmte Sandwichpaneele
Authors: Berner Klaus
Published: May 2010

Zur Zeit werden fast ausschließlich gerade, ebene Sandwichbauteile – meist bestehend aus dünnen metallischen Deckschichten und einem Kern aus Polyurethan oder Mineralwolle, für Wandverkleidungen und Dacheindeckungen großtechnisch eingesetzt. Die Elemente werden dabei auf eine tragende Unterkonstruktion montiert. Die Verwendung dieser Sandwichbauteile, einschließlich eines genau definierten Nachweisverfahrens, ist in der europäischen Norm DIN EN 14509 geregelt. Die statischen Systeme entsprechen Einfeld‐ oder Durchlaufträgern, wobei stets bei den Nachweisen die Nachgiebigkeit der Kernschicht beachtet werden muss (Sandwichtheorie).

Zur Erweiterung der Marktchancen ist es sicher interessant, alternative Bauweisen unter Verwendung von Sandwichbauteilen zu erforschen und zu entwickeln. Eine Alternative ist zum Beispiel die Verwendung von gekrümmten Sandwichbauteilen, die sowohl in architektonischer als auch in statischer Hinsicht innovative Lösungen für spezielle Dachkonstruktion ermöglichen. Die gekrümmten Bauteile können in statischer Hinsicht als Zweigelenkbogen ausgeführt werden und unterscheiden sich dadurch generell gegenüber den Trägersystemen der geraden Elemente. Eine vergleichende Gegenüberstellung der Bauweisen, einschließlich der konstruktiven Besonderheiten, zeigt Möglichkeiten und Effizienz bei der Verwendung von gekrümmten Bauteilen.

Curved sandwich panels. At the moment almost all straight flat sandwich panels, mostly consisting of thin metal faces and a core of polyurethane or mineral wool, are used either as wall claddings or roof coverings. For this purpose the elements are mounted on load bearing substructures. The application of these panels, including an accurate method for design by calculation, is regulated in the European standard DIN EN 14509. The static systems are one‐ or multi‐span bending beams. For the design the shear flexibility of the core shall be always taken into account (Sandwich‐Theory). To broaden the market for sandwich panels it is certainly interesting to research and develop alternative construction methods with sandwich panels. One alternative is e.g. the application of curved panels, which offer for architectural and statical regards innovative solutions for special constructions. The curved panels could be used as arch‐constructions, which are definitely different static systems in comparison to the beam‐systems of the flat panels. On the base of a comparison of the two construction methods, also regarding the constructive details, the possibilities and the efficiency are shown with the application of curved panels.
Physiological Levels of Reactive Oxygen Species Are Required to Maintain Genomic Stability in Stem Cells
Authors: Li Tao-Sheng , Marbán Eduardo
Published: May 2010

Stem cell cytogenetic abnormalities constitute a roadblock to regenerative therapies. We investigated the possibility that reactive oxygen species (ROSs) influence genomic stability in cardiac and embryonic stem cells. Karyotypic abnormalities in primary human cardiac stem cells were suppressed by culture in physiological (5%) oxygen, but addition of antioxidants to the medium unexpectedly increased aneuploidy. Intracellular ROS levels were moderately decreased in physiological oxygen, but dramatically decreased by the addition of high-dose antioxidants. Quantification of DNA damage in cardiac stem cells and in human embryonic stem cells revealed a biphasic dose-dependence: antioxidants suppressed DNA damage at low concentrations, but potentiated such damage at higher concentrations. High-dose antioxidants decreased cellular levels of ATM (ataxia-telangiectasia mutated) and other DNA repair enzymes, providing a potential mechanistic basis for the observed effects. These results indicate that physiological levels of intracellular ROS are required to activate the DNA repair pathway for maintaining genomic stability in stem cells. The concept of an “oxidative optimum” for genomic stability has broad implications for stem cell biology and carcinogenesis.
Cocaine causes deficits in radial migration and alters the distribution of glutamate and GABA neurons in the developing rat cerebral cortex
Authors: Lee Chun‐Ting , Chen Jia , Worden Lila T. , Freed William J.
Published: May 2010

Prenatal cocaine exposure induces cytoarchitectural changes in the embryonic neocortex; however, the biological mechanisms and type of cortical neurons involved in these changes are not known. Previously, we found that neural progenitor proliferation in the neocortical ventricular zone (VZ) is inhibited by cocaine; here, we examine the changes in cortical neurogenesis and migration of glutamate and GABA neurons induced by prenatal cocaine exposure. Pregnant rats received 20 mg/kg of cocaine intraperitoneally twice at an interval of 12 h during three periods of neocortical neurogenesis. Neocortical area and distribution of developing neurons were examined by counting Tuj1+, glutamate+, or GABA+ cells in different areas of the cerebral cortex. Cocaine decreased neocortical area by reducing the size of the Tuj1+ layer, but only when administered during early periods of neocortical neurogenesis. The number of glutamatergic neurons was increased in the VZ but was decreased in the outer cortical laminae. Although the number of GABA+ neurons in the VZ of both the neocortex and ganglionic eminences was unchanged, GABA+ cells decreased in all other neocortical laminae. Tangential migration of GABA+ cells was also disrupted by cocaine. These findings suggest that in utero cocaine exposure disturbs radial migration of neocortical neurons, possibly because of decreased radial glia guiding support through enhanced differentiation of neocortical VZ progenitors. Cocaine interrupts radial migration of both glutamatergic and GABAergic neurons within the neocortex, in addition to the tangential migration of GABAergic neurons from the subcortical telecephalon. This may result in abnormal neocortical cytoarchitecture and concomitant adverse functional effects. Synapse 65:21–34, 2011. © 2010 Wiley‐Liss, Inc.
Levator avulsion is a risk factor for cystocele recurrence
Authors: Dietz H. P. , Chantarasorn V. , Shek K. L.
Published: May 2010

Objectives

To determine whether levator avulsion is a risk factor for recurrence after cystocele repair.

Methods

This was an audit of women who underwent anterior colporrhaphy at a tertiary hospital between 2002 and 2005, who were followed up by interview, clinical examination and four‐dimensional translabial ultrasound examination 3–6 years later.

Results

Of 242 patients identified through theater records we were able to contact 171 (71%). Of 83 who agreed to attend, 24 (29%) reported symptoms of recurrent prolapse. There were 33 (40%) recurrent cystoceles (Stage 2 + ), and 34 (41%) had a significant cystocele on ultrasound examination. On pelvic floor tomographic ultrasound examination, a levator avulsion was detected in 29 (35%) patients. The relative risk of recurrence in women with avulsion was 3.9 (95% CI, 2.4–5.8) when ultrasound criteria of recurrent cystocele were used, and 2.9 (95% CI, 1.7–4.5) when using clinical staging.

Conclusion

Levator avulsion is associated with a relative risk of 3–4 for cystocele recurrence after anterior colporrhaphy. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.
A simple learning automata‐based solution for intrusion detection in wireless sensor networks
Authors: Misra Sudip , Krishna P. Venkata , Abraham Kiran Isaac
Published: May 2010

The protocols in designed for Wireless Sensor Networks (WSN) have a unique requirement for being of low complexity and energy‐efficient. Due to their possible deployment in remote locations for civil, educational, scientific, and military purposes, security, which includes intrusion detection and intrusion prevention, is of utmost importance. In this paper, we propose a simple, low complexity, and energy‐aware protocol for intrusion detection in WSN. The protocol is self‐learning and distributed in nature. The distributed nature avoids all other nodes being sacrificed when a single node is compromised. The protocol juxtaposes the concept of stochastic learning automata on packet sampling mechanism to achieve an energy aware intrusion detection system. We have rigorously evaluated the performance of our proposed solution by performing a variety of experiments and have found our solution approach to be promising. In the experiments performed the highest achieved packet sapling efficiency was 97%. Copyright © 2010 John Wiley & Sons, Ltd.
Survey and experiments of WIA‐PA specification of industrial wireless network
Authors: Liang Wei , Zhang Xiaoling , Xiao Yang , Wang Fuqiang , Zeng Peng , Yu Haibin
Published: May 2010

Wireless process control has been a popular topic recently in the field of industrial control. In the industrial field, wireless technologies are considered despite the lack of an ideal industrial wireless standard. However, application development of industrial wireless networks is slow due to the lack of an ideal standard. Open standards are the foundation of industrial wireless application extensions. This paper first summarizes a standardized process for industrial wireless network technologies and then introduces network composition, network topology, protocol stack architecture, and some key protocol technologies of WIA‐PA, which is an international specification of industrial wireless networks for process automation. Furthermore, a comparison between WIA‐PA and other main industrial wireless network specifications like WirelessHART and ISA100.11a is provided. Architecture and key technologies of a WIA‐PA are also introduced. Our first‐hand experiences in developing WIA‐PA testbed based on the modularization method are given. Finally, experiment results illustrate the performance and efficiency of WIA‐PA. Copyright © 2010 John Wiley & Sons, Ltd.