bluuebunny/crossref_metadata_2025 huggingface dataset:
A boundary problem for an elliptic system of differential equations involving a discontinuous weight
Authors: Faierman M.
Published: February 2009

We consider a boundary problem for an elliptic system of differential equations in a bounded region Ω ⊂ ℝn and where the spectral parameter is multiplied by a discontinuous weight function ω (x)= diag(ω1(x), …, ωN (x)). The problem is considered under limited smoothness assumptions and under an ellipticity with parameter condition. In a recent paper, Denk, Faierman, and Möller have studied this problem under the assumption that the ωj (x)–1 are essentially bounded in Ω. In this paper we suppose that ω (x) vanishes identically in a proper subregion ΩN 0 of Ω and that the ωj (x)–1's are essentially bounded in Ω′ = Ω\. By appealing to a result of Faierman pertaining to the Calderón method of reducing a boundary problem for a region to a problem on its boundary, we are able remove the region ΩN 0 altogether and reduce our boundary problem to one for the region Ω′ with a special type of boundary condition on ΓN 0. Since this latter problem falls into a class of problems studied in the paper by Denk et al. cited above, all the spectral theory derived in that paper carries over directly to the problem which we are presently considering. Thus in this way we establish the spectral theory for the boundary problem under consideration here (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On a resolvent estimate of the Stokes system in a half space arising from a free boundary problem for the Navier–Stokes equations
Authors: Shibata Y. , Shimizu S.
Published: February 2009

In this paper we consider a resolvent problem of the Stokes operator with some boundary condition in the half space, which is obtained as a model problem arising in evolution free boundary problems for viscous, incompressible fluid flow. We show standard resolvent estimates in the Lq framework (1 < q < ∞), applying some kernel estimates to concrete solution formulas. The Volevich trick in [21] plays a fundamental role in estimating solutions (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
M ‐functions for closed extensions of adjoint pairs of operators with applications to elliptic boundary problems
Authors: Brown B. M. , Grubb G. , Wood I. G.
Published: February 2009

In this paper, we combine results on extensions of operators with recent results on the relation between the M ‐function and the spectrum, to examine the spectral behaviour of boundary value problems. M ‐functions are defined for general closed extensions, and associated with realisations of elliptic operators. In particular, we consider both ODE and PDE examples where it is possible for the operator to possess spectral points that cannot be detected by the M ‐function (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Do polymorphisms in the familial Parkinsonism genes contribute to risk for sporadic Parkinson's disease?
Authors: Sutherland Greg T. , Halliday Glenda M. , Silburn Peter A. , Mastaglia Frank L. , Rowe Dominic B. , Boyle Richard S. , O'Sullivan John D. , Ly Tina , Wilton Steve D. , Mellick George D.
Published: February 2009

Recent whole genome association studies provided little evidence that polymorphisms at the familial Parkinsonism loci influence the risk for Parkinson's disease (PD). However, these studies are not designed to detect the types of subtle effects that common variants may impose. Here, we use an alternative targeted candidate gene approach to examine common variation in 11 genes related to familial Parkinsonism. PD cases (n = 331) and unaffected control subjects (n = 296) were recruited from three specialist movement disorder clinics in Brisbane, Australia and the Australian Electoral Roll. Common genetic variables (76 SNPs and 1 STR) were assessed in all subjects and haplotype, genotype, and allele associations explored. Modest associations (uncorrected P < 0.05) were observed for common variants around SNCA, UCHL1, MAPT, and LRRK2 although none were of sufficient magnitude to survive strict statistical corrections for multiple comparisons. No associations were seen for PRKN, PINK1, GBA, ATP13A2, HTRA2, NR4A2, and DJ1. Our findings suggest that common genetic variables of selected PD‐related loci contribute modestly to PD risk in Australians. © 2009 Movement Disorder Society
Normal interhemispheric inhibition in persistent developmental stuttering
Authors: Sommer Martin , Knappmeyer Kathrin , Hunter Evke Jane , Gudenberg Alexander Wolffvon , Neef Nicole , Paulus Walter
Published: February 2009

Imaging studies suggest a right hemispheric (pre)motor overactivity in patients with persistent developmental stuttering (PDS). The interhemispheric inhibition (IHI) studied with transcranial magnetic stimulation is an established measure of the interplay between right and left motor areas. We assessed IHI in 15 young male adults with PDS and 15 age‐matched fluent‐speaking subjects. We additionally studied the ipsilateral silent period (iSP) duration. We found no significant between‐group difference for IHI or for iSP duration. We conclude that the interplay between the primary motor cortices is normal in patients with PDS. The abnormal right motor and premotor activity observed in functional imaging studies on PDS are not likely to reflect altered primary motor cortex excitability, but are likely to have a different origin. © 2009 Movement Disorder Society
Mortality in Parkinson's disease: A 20‐year follow‐up study
Authors: Diem‐Zangerl Anja , Seppi Klaus , Wenning Gregor K. , Trinka Eugen , Ransmayr Gerhard , Oberaigner Wilhelm , Poewe Werner
Published: February 2009

We determined mortality rates and predictors of survival in 238 consecutive patients with Parkinson's disease (PD) with symptom onset between 1974 and 1984. All patients were regularly followed at the Movement Disorder Clinic (Department of Neurology at the Innsbruck Medical University) until December 31, 2004, or death. As of December 31, 2004, 189 patients had died. Standardized mortality ratios (SMRs) increased over time. SMRs were 0.6 (95% CI 0.4–1.0) by 5 years, 0.9 (95% CI 0.7–1.2) by 10 years, 1.2 (95% CI 1.0–1.4) by 15 years, and 1.3 (95% CI 1.1–1.5) by 20 to 30 years. SMR for male patients was significantly increased to 1.3 (95% CI 1.1–1.6), whereas SMR increase of 1.2 (0.9–1.4) observed in female patients was not significant. Significantly increased SMRs were detected in patients with younger and older age of onset. Male gender, gait disorder, lack of tremor, and lack of asymmetry as presenting clinical features predicted poor survival in a Cox's proportional hazard analysis. This study demonstrates similar survival of patients with PD to the normal control population up to a disease duration of 10 years, followed by a modest rise of mortality with disease duration beyond 10 years compared with the general population. Under regular specialist care using all currently available therapies life expectancy in PD does not appear seriously compromised, but male gender, gait disorder, and absent rest tremor at presentation are associated with poorer long‐term survival. © 2009 Movement Disorder Society
Friedreich's ataxia impact scale: A new measure striving to provide the flexibility required by today's studies
Authors: Cano Stefan J. , Riazi Afsane , Schapira Anthony H.V. , Cooper J. Mark , Hobart Jeremy C.
Published: February 2009

To develop, using modern techniques of rating scale construction, a new patient reported rating scale for clinical studies of Friedreich's ataxia (FA) that strives to meet the measurement needs of different types of study. Qualitative research methods were used to generate a conceptual framework of the impact of FA, and a pool of items necessary to construct a subscale for each area identified. This item pool was then administered to 492 people with FA. Rasch measurement methods guided scale construction. Eight areas for measurement were identified (speech, upper limb functioning, lower limb functioning, body movement, complex tasks, isolation, mood, self perceptions), and a 126‐item scale constructed (FA Impact Scale; FAIS). In addition, three shorter versions were developed to illustrate how the FAIS can be adapted for observational studies, more disabled, and less disabled samples of people with FA. The FAIS is a psychometrically sound 126‐item measure from which subsets of items can be selected to meet the needs of different studies. Importantly, all versions can be referred back to the original scale. This study shows one of the many clinical advantages of using Rasch measurement methods to construct rating scales. © 2009 Movement Disorder Society
Beneficial effect of transcranial magnetic stimulation on sleep in Parkinson's disease
Authors: van Dijk Karin D. , Møst Els I.S. , Van Someren Eus J.W. , Berendse Henk W. , van der Werf Ysbrand D.
Published: February 2009

Sleep disorders are common in Parkinson's disease (PD) and have profound negative influences on quality of life. Sleep structure in healthy participants can be changed by repetitive transcranial magnetic stimulation (rTMS), but this has never been studied systematically in PD. Therefore, we characterized sleep in PD patients and examined effects of rTMS using a combination of actigraphy and a pressure sensitive pad. Thirteen PD patients received 5 Hz rTMS over the motor or parietal cortex. Actigraphic sleep estimates were obtained before, during and after rTMS, as well as compared with 8 healthy, age‐matched controls. Motor symptoms and mood were evaluated before and after rTMS. Mixed‐model regression analyses indicated that PD patients slept shorter (350 ± 17 vs. 419 ± 24 min., P = 0.02), more fragmented (fragmentation index 41 ± 4 vs. 22 ± 2, P = 0.0004) and had a lower sleep efficiency (77 ± 2 vs. 86 ± 2%, P = 0.002) and longer nocturnal awakenings (3.4 ± 0.2 vs. 2.3 ± 0.2 min., P = 0.003) than healthy controls. rTMS over the parietal, but not over the motor cortex improved sleep fragmentation (P = 0.0002) and sleep efficiency (P = 0.0002) and reduced the average duration of nocturnal awakenings (P = 0.02). No change of motor symptoms or mood was observed. Disturbed sleep in PD patients may partly be reversed by parietal rTMS, without affecting motor symptoms or mood. © 2009 Movement Disorder Society
Phenotype variability in spinocerebellar ataxia type 2: A longitudinal family survey and a case featuring an unusual benign course of disease
Authors: Hering Sascha , Achmüller Clemens , Köhler Andrea , Poewe Werner , Schneider Raine , Boesch Sylvia M.
Published: February 2009

We report a 67 years old female patient out of a multigenerational family with spinocerebellar ataxia type 2 (SCA2) with an unusually benign course of disease. Although all SCA2 gene carriers have by now developed the predominant gait ataxia and brainstem oculomotor dysfunction, the index patient presented with a very mild course of disease, scoring only six points on the Scale for the Assessment and Rating of Ataxia after a disease duration of 13 years. Otherwise, intragenerational variability within family members such as the age at onset of disease and the course of disease was low. Reinvestigation of the genetic background variables in the SCA2 gene carrier reported here showed 27 repeats in the normal allele and 37 noninterrupted repeats in the abnormal allele. Interestingly, this patient has been taking lithium‐carbonate over more than 30 years because of psychotic depression. Although anecdotic, this SCA2 case may provide promising insights into possible disease modifying mechanisms in SCA2. © 2009 Movement Disorder Society
Chiral self‐discrimination of the enantiomers of α‐phenylethylamine derivatives in proton NMR
Authors: Huang Shao‐Hua , Bai Zheng‐Wu , Feng Ji‐Wen
Published: February 2009

Two types of chiral analytes, the urea and amide derivatives of α‐phenylethylamine, were prepared. The effect of inter‐molecular hydrogen‐bonding interaction on self‐discrimination of the enantiomers of analytes has been investigated using high‐resolution 1H NMR. It was found that the urea derivatives with double‐hydrogen‐bonding interaction exhibit not only the stronger hydrogen‐bonding interaction but also better self‐recognition abilities than the amide derivatives (except for one bearing two NO2 groups). The present results suggest that double‐hydrogen‐bonding interaction promotes the self‐discrimination ability of the chiral compounds. Copyright © 2009 John Wiley & Sons, Ltd.
New carbasugars from Streptomyces lincolnensis
Authors: Sedmera Petr , Halada Petr , Pospíšil Stanislav
Published: February 2009

Two new carbasugars (9 and 10) were isolated from Streptomyces lincolnensis DSM 40355 along with streptol (valienol, 8), gabosine I (valienone, 14), and glucosylglycerate. The reported 1H and 13C assignments are based on 1D (1H, 13C, 1D‐TOCSY, homodecoupling) and 2D (gCOSY, J‐resolved, TOCSY, ROESY, gHSQC, gHMBC) NMR techniques and electrospray ionization FT mass spectrometry (ESI FTMS). Copyright © 2009 John Wiley & Sons, Ltd.
Trauma and amputations in 19th century miners from Kimberley, South Africa
Authors: Van der Merwe A. E. , Steyn M. , L'Abbé E. N.
Published: February 2009

Trauma is the result of violent accidental or therapeutic events that cause physical or psychological injury. The frequencies and types of trauma within a population can give important information regarding their lifestyle as well as the quantity and quality of medical care available to them. The purpose of this study was to assess the incidence of trauma in the Gladstone sample population with regards to the presence of interpersonal violence a hazardous working environment strenuous working requirements and the availability of medical care. The individuals studied here were diamond miners from Kimberley dating to the late 19th century. A total of 107 well‐preserved skeletons were excavated from unmarked graves after accidental discovery. This sample included 86 males 15 females and 6 individuals of unknown sex. The majority of individuals (71%) were between 19 and 45 years of age. The remains were most likely those of migrant mine workers of low socioeconomic status who had passed away at the local hospitals. All bones were visually assessed for macroscopic indications of traumatic bone alterations and compared to standard palaeopathological texts and photographs. A total of 27% (n = 28) of the individuals in the sample presented with well‐healed healing or perimortem fractures. Fractures to the skull encompassed 49% (n = 20) of all the fractures that were observed. A total of six (6%) amputations were noted. Spondylolysis was observed in 7% (n = 7) of the individuals within the sample and longstanding subluxation was noted in two individuals. The high incidences of cranial fractures within this population are suggestive of high levels of interpersonal violence while long bone fractures spondylolysis and evidence of longstanding subluxations are indicative of the strenuous work requirements and the high‐risk environment to which these individuals were exposed. When considering the presence of well‐reduced fractures and healed amputations it seems that adequate medical care was available to at least some members of this community. Copyright © 2009 John Wiley & Sons Ltd.

This article was published online on 17 February 2009. An error was subsequently identified. This notice is included in the online and print versions to indicate that both have been corrected 3 November 2009.
Identification of an aptamer targeting hnRNP A1 by tissue slide‐based SELEX
Authors: Li Shaohua , Xu Hua , Ding Hongmei , Huang Yanping , Cao Xiaoxiao , Yang Guang , Li Jie , Xie Zhigang , Meng Yuhong , Li Xiaobing , Zhao Qiang , Shen Beifen , Shao Ningsheng
Published: February 2009

We report a new in situ tissue slide‐based SELEX strategy targeting neoplastic tissues from breast cancer patients. The methodology, using the molecular differences between clinical specimens, can evolve aptamers to all fractions of tissue. The aptamers may be used as new molecular probes for pathological diagnosis and tumour imaging, and also to reveal the molecular differences that are responsible for the diseases. The specific aptamers were enriched by unequal length strand PCR employing a structured (−) strand primer. After 12 rounds of selection, using the paraffin tissue sections from infiltrating ductal carcinomas as targets, and using the adjacent normal tissue from the same case as controls, one of the enriched ssDNA aptamers, BC15, was selected from a nucleic acid library and characterized as recognizing breast cancer cells either within the tissue sections or from the culture medium, but only weakly binding to adjacent normal cells or immortalized breast cell line MCF10A. The calculated equilibrium dissociation constants (Kd) of BC15 bound to MCF7 cells was 111.0 ± 36.9 nM. Through streptavidin magnetic beads mediated affinity purification assay followed by mass spectrometry identification and western blot confirmation, the target of BC15 was characterized to be hnRNP A1, which was further verified to be specifically and highly expressed in cancerous tissues of breast by hnRNP A1 antibody immunostaining as well as western blot. BC15 aptamer was also used to probe cancer cells in tissues from other pathological types of breast cancers including lobular carcinoma, ductal carcinoma complicated with lobular carcinoma, comedo carcinoma, and lymph node metastasis of breast ductal carcinoma origin or breast lobular carcinoma origin. Therefore, tissue slide‐based SELEX holds promise in identifying tumour markers and developing specific molecular probes for cancer diagnosis. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Enabling dignity in care through practice development with older people
Authors: Webster Jonathan , Coats Emma , Noble Guy
Published: February 2009

This article describes how a programme of practice development enabled practitioners working within an acute health services provider organization to develop practice through joint learning with older people focused on dignity in care using creative arts. Copyright © 2009 John Wiley & Sons, Ltd.
Comparative gender biases in models of personality disorder
Authors: Samuel Douglas B. , Widiger Thomas A.
Published: February 2009

The potential of gender bias within the DSM personality disorders has long been a concern of scholars and clinicians. Over the past three decades, research findings utilizing the case vignette methodology have repeatedly indicated a gender bias within the histrionic diagnosis. The current study replicates these findings using a novel case vignette, but extends them to investigate the potential for gender biases within an alternative dimensional model of personality—the Five‐Factor Model (FFM). One hundred and forty‐one practicing clinicians rated either a male or a female version of a case vignette in terms of either the FFM or the personality disorders from the Diagnostic and Statistical Manual of Mental Disorders (DSM‐IV‐TR). The results supported the concern of gender bias, with the female case less likely to be diagnosed as antisocial and the male case less likely to be diagnosed as histrionic. However, when the FFM conceptualizations of these two disorders were compared, no significant differences were noted. The results indicate that the FFM may be less prone to gender bias than the current DSM nomenclature. Copyright © 2009 John Wiley & Sons, Ltd.
Spin‐decoherence effects on the pumped spin‐dependent transport through a quantum dot
Authors: Pan Hui , Li Zheng , Duan Su‐Qing , Chu Wei‐Dong , Zhang Wei
Published: February 2009

We theoretically study the spin‐decoherence effects on the pumped spin‐polarized current through a quantum dot subject to a rotating magnetic field and coupled to two ferromagnetic electrodes. The dependence of the current on the magnetic moment orientation angle of the two leads is greatly influenced by the spin pump and the spin decoherence. The spin pump destroys the normal spin‐valve effects, and the spin decoherence makes the current exhibiting a quite complicated angle dependence. These distinct transport behaviors can be used as electrical schemes for detection of electron spin resonance and spin decoherence. Moreover, the current is closely related to the magnetic Rabi frequency and the detuning, in which the spin decoherence also plays an important role, and thus the pumped spin‐polarized current can be used as a sensitive tool to measure these pumping parameters. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Absorption spectroscopy and energy levels of rare earth impurity centres in Srx Ba1–xNb2O6 crystals
Authors: Demirbilek R. , Kutsenko A. B. , Pankrath R. , Kapphan S. E.
Published: February 2009

The absorption spectra of Ce3+, Nd3+, Eu3+, Tb3+, Er3+, Tm3+ and Yb3+ rare earth (RE) impurity ions incorporated in Srx Ba1–x Nb2O6 (SBN) crystals were studied in a wide spectral range from the visible to the mid‐infrared. On the basis of the analysis of the Ce3+ absorption line shapes and their polarization properties the conclusion was drawn about the incorporation of multiple Ce3+ centres mostly in the position A1 of the crystal lattice of SBN. From the observed temperature dependence of the Ce3+ absorption line broadening the electron coupling strength (160 cm–1) and effective phonon energy (300 cm–1) were determined. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
CdSe quantum dot in a ZnSe nanowire as an efficient source of single photons
Authors: Tribu A. , Sallen G. , Aichele T. , Bougerol C. , André R. , Poizat J. P. , Tatarenko S. , Kheng K.
Published: February 2009

We report on our development of fabrication of CdSe QD in ZnSe nanowire. We have been able to obtain high quality structures with very good optical properties. This has allowed us to measure photon emission from single quantum dots and to demonstrate photon antibunching. We show that this new type of II–VI quantum dot is very promising for high temperature operation. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Group III element substitution effects on Eu‐doped thiogallate phosphors
Authors: Kato Ariyuki , Ohno Katsuyoshi , Honda Tatsuya , Noguchi Hiroshi , Azlinda Nora
Published: February 2009

Photoluminescence properties of II‐III2S4:Eu (II=Ca, Sr, Ba; III=Ga, In, Y, La; Eu concentration was 1 mol%) have been investigated systematically. In Ga compounds, well‐known green∼yellow emissions are observed, while the emissions become very weak in In substituted compounds.

In III=Y or La compounds, when II=Ca or Sr, red∼infrared emissons which seem to be due to phonon‐terminated transition of the Eu2+ ions are observed, while when II=Ba, strong sharp lines due to the Eu3+ions are detected. These spectral changes are discussed in terms of the effective ionic radii and the sulfur vacancies (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Capabilities of CdZnTe‐based Schottky diodes for detection of optical and X/γ‐ray radiation
Authors: Maslyanchuk O. L. , Kosyachenko L. A. , Gnatyuk V. A. , Aoki T. , Rarenko I. M. , Sklyarchuk V. M.
Published: February 2009

The electrical and photoelectric properties of Schottky diodes based on low‐resistivity (ρ = 103‐104 Ω·cm) and semi‐insulating (ρ ≈ 107 Ω·cm) Cd1‐xZnxTe (x = 0‐0.2) single crystals are investigated and use of the diodes as detectors, respectively, for optical and X‐ and γ‐ray radiation is analyzed. The charge transport properties of both types of Schottky diodes are shown to be governed by generation‐recombination in the space‐charge region in the frame of the Sah‐Noyce‐Shockley theory. The detection spectrum of Cd1–x Znx Te‐bassed X/γ‐ray detectors with Schottky diodes is studied. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structure and optical properties of PbS‐SnS mixed crystal thin films
Authors: Unuchak D. M. , Bente K. , Kloess G. , Schmitz W. , Gremenok V. F. , Ivanov V. A. , Ukhov V.
Published: February 2009

Thin films of lead tin sulphide PbSnS2 were deposited on glass substrates at 100 °C at vacuum pressure of 3×10–6 mbar using a thermal evaporation method. Scanning electron microscopy (SEM) and X‐ray characterization revealed that thin films were monophase and polycrystalline. The average particle size was approximately 28 nm. Absorption coefficient of PbSnS2 thin films (∼105 cm–1) was found from transmission optical spectroscopy measurements. Its fundamental absorption edge is shown to be 1.65 eV with direct allowed transition recommended for photovoltaic application. Thermoelectric measurements showed the materials to be p‐type in nature. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of CuAlS2 with small indium content
Authors: Shim YongGu , Hasegawa Kouji , Wakita Kazuki , Mamedov Nazim , Yamamoto Nobuyuki
Published: February 2009

Bulky CuAlS2 single crystals were grown by traveling‐heater method (THM) using indium solvent, and shown to have small indium content and represent solid solutions CuAl1–xInxS2 of CuAlS2‐CuInS2 system The composition with x = 0.24 has been studied by spectroscopic ellipsometry at room temperature. The principal components of dielectric function, ϵ⊥ (E⊥C) and ϵ∥ (E∥C), have been obtained in the spectral range 0.75‐6.0 eV. The critical point analysis has been performed and the optical transitions responsible for the observed critical points have been assigned by taking account of the available electronic band structures of CuAlS2 and CuInS2. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Anomalous dissolution of microindentation deformed zone of ITO/Si coated system
Authors: Grabco D. , Shikimaka O. , Harea E. , Gehm N. , Schimmel Th. , Koch Thomas
Published: February 2009

The joint effect of a film and a substrate on the modification of the mechanical properties of an ITO/Si coated system (CS), a promising material for solar cells, and its response to an external load in comparison with the Si substrate were considered. An unusual combination of a pronounced crack formation and a plastic character of indenter–sample contact zone was revealed. This feature was accounted for a high brittleness of the Si substrate and the enhanced plasticity of the ITO film that improves the mechanical characteristics of the whole ITO/Si structure, which is useful for its operation. Another unexpected result, the anomalous etching (dissolution) of the ITO film near the indentations, was found out when the ITO/Si CS was subjected to an aggressive medium. A preferable dissolution of the ITO film was detected in the deformed zone near the indentation (Df), commensurable with the dimension of the substrate elastic/plastic dislocation free zone which was two or three times larger than the indentation diagonal (d) and approximately ten times larger than the dislocation rosette around indentation on the Si support. An assumption was made that the effect is basically determined by high internal stresses in this zone and, hence, by weaker atomic bonds as compared with the undeformed part of the material. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Use of Sequence‐Derived QSPR Descriptors for Predicting Highly Connected Proteins (Hubs) in Protein–Protein Interactions
Authors: Byler Kendall , Hsing Michael , Cherkasov Artem
Published: February 2009

Proteins essential for the viability of cells have been shown to have a higher probability of having a large number of interactions with other cell components. Thus it has been suggested that, by identifying the most connected proteins, hubs, in Protein Interaction Networks (PINs), one may discover essential proteins that may be then isolated as prospective drug targets. Such an approach bears particular importance for the development of new drugs against emergent and drug‐resistant pathogens such as Methicillin‐Resistant Staphylococcus aureus 252 (MRSA).
The Effect of Molecular Fields, Lattice Spacing and Analysis Options on CoMFA Predictive Ability
Authors: Mittal Ruchi R. , McKinnon Ross A. , Sorich Michael J.
Published: February 2009

Comparative Molecular Field Analysis (CoMFA) is a popular Three‐Dimensional Quantitative Structure–Activity Relationship (3D‐QSAR) method. The effect of varying molecular fields [CoMFA vs. Comparative Molecular Similarity Indices Analysis (CoMSIA)], lattice spacing and analysis options on predictive performance was assessed based on cross validated R2 values of 30 datasets taken from the literature. The CoMFA method results in statistically significantly higher cross validated R2 values compared to CoMSIA when only steric and electrostatic fields are used. When the hydrophobic molecular field is included in the CoMSIA analysis (as is most commonly the case) the difference between CoMFA and CoMSIA is no longer statistically significant. Addition of hydrogen bond field does not improve CoMFA predictivity. Although there was a trend towards increased predictivity with decreased lattice spacing, this was not statistically significant. Altering the default filtering criteria and cut‐off values for Lennard Jones and Coulomb fields also did not generally result in a statistically significant effect on predictive performance.
Analysis of impurities in streptomycin and dihydrostreptomycin by hydrophilic interaction chromatography/electrospray ionization quadrupole ion trap/time‐of‐flight mass spectrometry
Authors: Kawano Shin‐ichi
Published: February 2009

Impurities in streptomycin (STR) and dihydrostreptomycin (DHS) were investigated by hydrophilic interaction chromatography/electrospray ionization quadrupole ion trap/time‐of‐flight mass spectrometry (HILIC/ESI‐QIT/TOFMS). Samples were separated on a fused‐core silica column (100 mm × 2.1 mm i.d., particle size: 2.7 µm) with isocratic elution using 200 mM ammonium formate buffer (pH 4.5) and acetonitrile as mobile phase. Constant neutral loss survey in accurate mass measurement was carried out by QIT/TOFMS. Formulae, chemical structures of impurities in an STR sample were suggested with supporting results on the probable pathways of STR biosynthesis by Streptomyces griseus. Copyright © 2009 John Wiley & Sons, Ltd.
Elevated levels of hydroxylated phosphocholine lipids in the blood serum of breast cancer patients
Authors: Hammad Loubna A. , Wu Guangxiang , Saleh Marwa M. , Klouckova Iveta , Dobrolecki Lacey E. , Hickey Robert J. , Schnaper Lauren , Novotny Milos V. , Mechref Yehia
Published: February 2009

The difference in serum phospholipid content between stage‐IV breast cancer patients and disease‐free individuals was studied by employing a combination of chemometric statistical analysis tools and mass spectrometry. Chloroform‐extracted serum samples were profiled for their lipid class composition and structure using precursor ion, neutral loss, and product ion tandem mass spectrometric (MS/MS) scanning experiments. Changes in the relative abundance of phospholipids in serum as a consequence of cancer progression, measured through electrospray ionization (ESI) mass spectrometry of flow‐injected serum samples collected from 25 disease‐free individuals and 50 patients diagnosed with stage‐IV breast cancer, were statistically evaluated using principal component analysis (PCA), analysis of variance (ANOVA) and receiver operating characteristic (ROC) analysis. Lipids whose abundance changed significantly as a consequence of cancer progression were structurally characterized using product ion spectra, and independently quantified using precursor ion scan experiments against an internal standard of known concentration. Phosphocholine lipids that displayed a statistically significant change as a consequence of cancer progression were found to contain an oxidized fatty acid moiety as determined by MS3 experiments. Copyright © 2009 John Wiley & Sons, Ltd.
Electron ionisation mass spectral studies of bridgehead‐fused Δ2‐norbornanethiazolines
Authors: Martínez Antonio García , Vilar Enrique Teso , Jiménez Florencio Moreno , Martínez‐Ruiz Paloma , Vilaboa Ricardo Bernárdez
Published: February 2009

The electron ionisation (EI) mass spectra of a series of bridgehead‐fused Δ2‐norbornanethiazolines, a new class of bridgehead‐norbornane derivatives, have been studied and their cleavage mechanisms rationalised on the basis of the substituent shifts as well as on the identification of relevant peaks through accurate mass measurements and collision‐induced dissociation tandem mass spectrometric experiments. The fragmentation patterns of isomeric pairs of 6,6‐ and 10,10‐dimethylnorbornanethiazolines are almost identical, probably due to an initial isomerisation of molecular ion previous to the fragmentation. In general, the dominant peaks in the spectra of all the studied compounds originate from initial α‐cleavages of C(5)–C(6) or C(1)–C(10) bonds, followed by concomitant homolytic cleavage of C(1)–C(9) and C(7)–C(10) bonds. The driving force for this fragmentation pathway, directed by the gem‐dimethyl group, is the formation of a highly stabilised thiazolilmethyl cation which constitutes the base peak in all the spectra and allows the identification of these interesting ligands. Copyright © 2009 John Wiley & Sons, Ltd.
Study of active naphtodianthrone St John's Wort compounds by electrospray ionization Fourier transform ion cyclotron resonance and multi‐stage mass spectrometry in sustained off‐resonance irradiation collision‐induced dissociation and infrared multiphoton dissociation modes
Authors: Hecka Audrey , Maunit Benoît , Aubriet Frédéric , Muller Jean‐François
Published: February 2009

Five well‐known active naphtodianthrone constituents of Hypericum perforatum (St John's Wort) extracts have been investigated by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI‐FTICRMS) and ESI‐FTICRMSn. The studied compounds were hypericin, pseudohypericin, protohypericin, protopseudohypericin (biosynthetic precursors of the two former compounds, respectively) and isopseudohypericin (alkaline degradation product of pseudohypericin). Dissociation mass spectrometry measurements performed on the [M–H]− ion presented a variable efficiency as a function of the used activation mode. Sustained off‐resonance irradiation collision‐induced dissociation (SORI–CID) only led to a restricted number of fragment ions. In contrast, IRMPD ensured the detection of numerous product ions. Ions detected in ESI‐FTICRMS and ESI‐FTICRMSn experiments were measured with a very high mass accuracy (typically mass error is lower than 0.5 mDa at m/z close to 500) that allowed unambiguous formulae to be assigned to each signal observed in a mass spectrum. In spite of similar structures, specific fragmentation patterns were observed for the different compounds investigated. This study may be useful in the future to characterize in natural extracts these compounds (or derivatives of these compounds) by liquid chromatography/tandem mass spectrometry (LC/MS/MS) experiments by considering the MS/MS transitions highlighted in this paper. Copyright © 2009 John Wiley & Sons, Ltd.
Rapid detection and characterization of reactive drug metabolitesin vitrousing several isotope‐labeled trapping agents and ultra‐performance liquid chromatography/time‐of‐flight mass spectrometry
Authors: Rousu Timo , Pelkonen Olavi , Tolonen Ari
Published: February 2009

Reactive metabolites are believed to be one of the main reasons for unexpected drug‐induced toxicity issues, by forming covalent adducts with cell proteins or DNA. Due to their high reactivity and short lifespan they are not directly detected by traditional analytical methods, but are most traditionally analyzed by liquid chromatography/tandem mass spectrometry (LC/MS/MS) after chemical trapping with nucleophilic agents such as glutathione. Here, a simple but very efficient assay was built up for screening reactive drug metabolites, utilizing stable isotope labeled glutathione, potassium cyanide and semicarbazide as trapping agents and highly sensitive ultra‐performance liquid chromatography/time‐of‐flight mass spectrometry (UPLC/TOFMS) as an analytical tool. A group of twelve structurally different compounds was used as a test set, and a large number of trapped metabolites were detected for most of them, including many conjugates not reported previously. Glutathione‐trapped metabolites were detected for nine of the twelve test compounds, whereas cyanide‐trapped metabolites were found for eight and semicarbazide‐trapped for three test compounds. The high mass accuracy of TOFMS provided unambiguous identification of change in molecular formula by formation of a reactive metabolite. In addition, use of a mass defect filter was found to be a usable tool when mining the trapped conjugates from the acquired data. The approach was shown to provide superior detection sensitivity in comparison to traditional methods based on neutral loss or precursor ion scanning with a triple quadrupole mass spectrometer, and clearly more efficient detection and characterization of reactive drug metabolites with a simpler test setup. Copyright © 2009 John Wiley & Sons, Ltd.
Autonomous science for an ExoMars Rover–like mission
Authors: Woods Mark , Shaw Andy , Barnes Dave , Price Dave , Long Derek , Pullan Derek
Published: February 2009

In common with other Mars exploration missions, human supervision of Europe's ExoMars Rover will be mostly indirect via orbital relay spacecraft and thus far from immediate. The gap between issuing commands and witnessing the results of the consequent rover actions will typically be on the order of several hours or even sols. In addition, it will not be possible to observe the external environment at the time of action execution. This lengthens the time required to carry out scientific exploration and limits the mission's ability to respond quickly to favorable science events. To increase potential science return for such missions, it will be necessary to deploy autonomous systems that include science target selection and active data acquisition. In this work, we have developed and integrated technologies that we explored in previous studies and used the resulting test bed to demonstrate an autonomous, opportunistic science concept on a representative robotic platform. In addition to progressing the system design approach and individual autonomy components, we have introduced a methodology for autonomous science assessment based on terrestrial field science practice. © 2009 Wiley Periodicals, Inc.
Secure and practical key establishment for distributed sensor networks
Authors: Kotzanikolaou Panayiotis , Magkos Emmanouil , Vergados Dimitrios , Stefanidakis Michalis
Published: February 2009

Key establishment in sensor networks is a challenging task, due to the physical constraints of sensor devices and their exposure to several threats. Existing protocols based on symmetric cryptography are very efficient but they are weak against several node impersonation and insider attacks. On the other hand, asymmetric protocols are resilient to such attacks but unfortunately, they are not feasible for sensor networks, even in their most efficient versions (e.g. the elliptic curve (EC) Diffie‐Hellman family of key agreement protocols). In this paper, we present two pairwise key establishment protocols for sensor nodes in unattended distributed sensor networks (DSNs). The first protocol is hybrid and it combines asymmetric (elliptic curve (EC)) cryptography with symmetric key techniques. The second protocol is fully asymmetric. Furthermore, through simulations, we measure the efficiency of the proposed protocols in comparison with existing hybrid protocols. Our results show that under conditions, it is feasible for highly sensitive applications of static sensor networks to employ partial or fully asymmetric key establishment techniques and thus extend their security properties. Copyright © 2009 John Wiley & Sons, Ltd.
Developmental increase of asynchronic glutamate release from hippocampal synapses in mutant taiep rat
Authors: Fuenzalida Marco , Aliaga Esteban , Olivares Virginia , Roncagliolo Manuel , Bonansco Christian
Published: February 2009

During development, regulation of the strength of synaptic transmission plays a central role in the formation of mammalian brain circuitries. In taiep rat, a neurological mutant with severe reactive astrogliosis and demyelination, we have described alterations in the synaptic transmission in central neurons, characterized by asynchronous excitatory postsynaptic currents (ASYNEPSCs), because of delayed neurotransmitter release. This hippocampal synaptic dysfunction has been described in juvenile mutants, concomitantly with the appearance of their main glial alterations. However, it is unknown whether this abnormal synaptic activity is correlated with some alterations of synaptic maturation during the postnatal development. Using intracellular electrophysiological recordings and immunohistochemistry assays, we studied the maturation of CA3‐CA1 synapses in taiep rats. In taiep, the number of ASYNEPSCs evoked by conventional stimulation of Schaffer collaterals increases with age (P7–P30) and can be evoked by stimulation of single fiber. The amplitude and frequency of spontaneous EPSC (sEPSC) increased during the postnatal development in both control and taiep rats. However, in taiep, the increase of sEPSC frequency was significantly higher than in the control rats. The frequency of miniature EPSC (mEPSC) increased over the studied age range, without differences between taiep and control rats. In both control and taiep groups, the synaptophysin immunostaining (SYP‐IR) in the stratum radiatum of CA1 region was significantly lower in the juvenile (P30) than in the neonatal (P10) rats, suggesting that synaptic pruning is normally occurring in taiep, even when SYP‐IR was higher in taiep than control in both ages studied. These results suggest that, in taiep mutants, the asynchronic transmission is due to a dysfunction in the glutamate release mechanisms that progressively increases during development, which is not attributable to the existence of aberrant synaptic contacts. Synapse 63:502–509, 2009. © 2009 Wiley‐Liss, Inc.
Transperineal ultrasound imaging in prolonged second stage of labor with occipitoanterior presenting fetuses: how well does the ‘angle of progression’ predict the mode of delivery?
Authors: Kalache K. D. , Dückelmann A. M. , Michaelis S. A. M. , Lange J. , Cichon G. , Dudenhausen J. W.
Published: February 2009

Objectives

To compare the angle of progression on transperineal ultrasound imaging between different modes of delivery in prolonged second stage of labor with occipitoanterior fetal position.

Methods

We prospectively evaluated 41 women at term (≥ 37 weeks) with failure to progress in the second stage of labor. Only cases with occipitoanterior fetal position were included in the final analysis. These cases were classified into three groups: Cesarean section for failure to progress, vacuum extraction for failure to progress, and spontaneous delivery following prolonged second stage of labor. Transperineal ultrasound examination was performed just before digital examination and subsequent delivery. The angle between a line placed through the midline of the pubic symphysis and a line running from the inferior apex of the symphysis tangentially to the fetal skull (the so‐called ‘angle of progression’) was measured offline by an observer blinded to the mode of delivery.

Results

There were 26 cases with occipitoanterior fetal position (Cesarean section, n = 5; vacuum extraction, n = 16; spontaneous delivery, n = 5). Logistic regression analysis showed a strong relationship between the angle of progression and the need for Cesarean delivery (R2 measure of fit = 55%, likelihood ratio chi‐square P < 0.0001). When the angle of progression was 120°, the fitted probability of either an easy and successful vacuum extraction or spontaneous vaginal delivery was 90%.

Conclusions

This is the first report to document a strong relationship between an objective ultrasound marker (angle of progression) and the mode of delivery following prolonged second stage of labor with occipitoanterior fetal position. A predictive model using this parameter would allow better decision making regarding operative delivery for obstructed labor. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Three‐dimensional endoanal ultrasonography: intraobserver and interobserver agreement using scoring systems for classification of anal sphincter defects
Authors: Norderval S. , Dehli T. , Vonen B.
Published: February 2009

Objectives

To determine the degree of intraobserver and interobserver agreement for an experienced and an inexperienced sonologist using two scoring systems for ultrasonographic assessment of anal sphincter defects.

Methods

The study sample comprised the datasets of all women aged between 20 and 40 years who had attended our outpatient clinic and undergone a complete three‐dimensional (3D) endoanal ultrasound (EAUS) examination in the period from January 2003 to December 2005. The EAUS datasets were assessed twice independently by two sonologists: one with experience of > 400 3D EAUS assessments and one inexperienced sonologist who had performed approximately 50 assessments before the study. Cases with intraobserver disagreement were resolved by a third (final) assessment. The final assessment from each observer was used to determine the degree of interobserver agreement. Sphincter defects were classified according to our EAUS defect score and the Starck score.

Results

EAUS datasets of 55 women were included. Based on first vs. second assessments, intraobserver agreement for the experienced sonologist was good for our EAUS defect score (weighted kappa, 0.75) and the Starck score (weighted kappa, 0.73). Intraobserver agreement for the inexperienced sonologist was moderate for our EAUS defect score (weighted kappa, 0.58) and good for the Starck score (weighted kappa, 0.62). Interobserver agreement was good for both our EAUS defect score (weighted kappa, 0.65) and the Starck score (weighted kappa, 0.74).

Conclusions

Intraobserver and interobserver agreement was acceptable for both scoring systems. The experienced sonologist obtained a higher degree of intraobserver agreement than did the inexperienced sonologist. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
On the singularities of constrained tensegrity systems – application to a modified T3 model
Authors: Pirentis A.P. , Markatis S. , Lazopoulos K.A. , Lazopoulos A.K.
Published: February 2009

Singularity theory is applied for the study of constrained tensegrity systems. Previous studies have already been performed on non‐constrained systems; however, the present one allows for general non‐symmetric equilibrium configurations. A modified T3 tensegrity model comprising seven rigid bars, three elastic cables and one rotational spring is considered. The stability of this model is examined performing singularity theory for deformations under conservative quasistatic loading. Critical conditions for branching of the equilibrium paths are defined and their post‐critical behavior is discussed. Classification of the simple and compound singularities of the total potential energy function is effected. The theory is implemented into the fold catastrophe of the asymmetric configuration of the modified T3 tensegrity model and an elliptic umbilic singularity for the case of compound branching. It is pointed out that singularity studies with constraints demand a quite different mathematical approach than those without constraints.
Vektorfeldalgebren, Gruppenaktionen und das Keplerproblem
Authors: Hamburger C.
Published: February 2009

We supply an analytic proof of the theorem of Palais about the existence of a Lie group action on a compact manifold M with a Lie algebra 𝔳 of vector fields. Every compact connected integral manifold N of 𝔳 is then diffeomorphic to a homogeneous manifold. In the special case of a Lie algebra of Hamiltonian vector fields, the group action consists of symplectic diffeomorphisms. Applications are the non‐commutative version of the Cauchy initial value problem for Hamilton‐Jacobi systems and of Liouville's theorem. As examples with non‐compact M, we determine group actions for the harmonic oscillator and for Kepler's problem.