bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonribosomal cyclic peptides: specific markers of fungal infections
Authors: Jegorov Alexandr , Hajduch Marian , Sulc Miroslav , Havlicek Vladimir 
Published: June 2006

AbstractSome cyclic peptides and depsipeptides are synthesized in microorganisms by large multienzymes called nonribosomal peptide synthetases. The structures of peptide products originating in this way are complex and diverse and are microorganism‐specific. This work proposes the use of fungal cyclic peptides and depsipeptides as extremely specific markers of fungal infections. Since a reliable molecular tool for diagnosing fungal infections at an early stage is still missing, we present mass spectrometry as a new, modern, broadband (with respect to fungal strain) and specific tool for clinical mycologists. More than 40 different fungal species can be rapidly characterized according to specific families of cyclic peptides, and in some cases, a particular fungal strain can be identified on the basis of its cyclopeptide profile. This paper is also aimed at initiating discussion on the biological role of these secondary metabolites, especially of those synthesized by medically important strains. Proven cytotoxic, anti‐inflammatory or immunosuppressive activities of some cyclic peptides indicate that these molecules may contribute to the synergistic array of fungal virulence factors and support microbial invasion during fungal infection. In addition to an overview on recent mass spectrometric protocols for cyclic peptide sequencing, the structures of new peptides from Paecilomyces and Pseudallescheria are presented. Copyright © 2006 John Wiley & Sons, Ltd.
Non‐zwitterionic structures of aliphatic‐only peptides mediated the formation and dissociation of gas phase radical cations
Authors: Lam Corey N. W. , Ruan Eric D. L. , Ma C. Y. , Chu Ivan K. 
Published: June 2006

AbstractWe have investigated how the non‐zwitterionic and zwitterionic structures of aliphatic‐only tripeptides affect the formation and dissociation of peptide radical cations in the gas phase. The non‐zwitterionic forms of the aliphatic‐only peptides in their metal complexes play an important role in determining whether the electron transfer pathway predominates. We extended this study by synthesizing permanent non‐zwitterionic and zwitterionic forms of aliphatic‐only peptide radical cations and exploring their reactivities in the gas phase. Collision‐induced dissociation spectra demonstrated the feasibility of generating both non‐zwitterionic and zwitterionic forms. Radical cations in zwitterionic forms may indeed mediate the β and γ carbon–carbon bond cleavages of leucine and isoleucine side chains from the GlyGlyXle radical peptides; this feature allows leucine and isoleucine residues to be distinguished unambiguously. Copyright © 2006 John Wiley & Sons, Ltd.
Loss of arginase I results in increased proliferation of neural stem cells
Authors: Becker‐Catania Sara G. , Gregory Teresa L. , Yang Yawei , Gau Chia‐Ling , de Vellis Jean , Cederbaum Stephen D. , Iyer Ramaswamy K. 
Published: June 2006

AbstractLoss of arginase I (AI) results in a metabolic disorder characterized by growth retardation, increased mental impairment and spasticity, and potentially fatal hyperammonemia. This syndrome plus a growing body of evidence supports a role for arginase and arginine metabolites in normal neuronal development and function. Here we report our initial observations of the effects of AI loss on proliferation and differentiation of neural stem cells (NSCs) isolated from the germinal zones of embryonic and newborn AI knockout (KO) mice compared with heterozygous (HET) and wild‐type (WT) control animals. By using both short and long‐term proliferation assays (3 and 10 days, respectively), we found a 1.5–2‐fold increase in the number of KO cells compared with WT. FACS analysis showed an increase in KO cells in the synthesis phase of the cell cycle vs. WT cells. After NSC differentiation, AI‐deficient cells expressed β‐tubulin, SMI81 (SNAP25), glial fibrillary acidic protein, and CNPase, which are markers consistent with neurons, astrocytes, and oligodendrocytes. Many KO cells exhibited a more mature morphology and expressed mature neuronal markers that were decreased or not present in HET or WT cells. Limited, comparative expression array and quantitative RT‐PCR analysis identified differences in the levels of several mRNAs encoding structural, signaling, and arginine metabolism proteins between KO and WT cells. The consequence of these changes may contribute to the differential phenotypes of KO vs. WT cells. It appears that AI may play an important and unanticipated role in growth and development of NSCs. © 2006 Wiley‐Liss, Inc.
Matrix effects in quantitative pesticide analysis using liquid chromatography–mass spectrometry
Authors: Niessen W.M.A. , Manini P. , Andreoli R. 
Published: June 2006

AbstractCombined liquid chromatography–mass spectrometry using electrospray or atmospheric‐pressure chemical ionization has become an important tool in the quantitative analysis of pesticide residues in various matrices in relation to environmental analysis, food safety, and biological exposure monitoring. One of the major problems in the quantitative analysis using LC–MS is that compound and matrix‐dependent response suppression or enhancement may occur, the so‐called matrix effect. This article reviews issues related to matrix effects, focusing on quantitative pesticide analysis, but also paying attention to expertise with respect to matrix effects acquired in other application areas of LC–MS, especially quantitative bioanalysis in the course of drug development. © 2006 Wiley Periodicals, Inc.
Economic burden of Parkinson's disease in a developing country: A retrospective cost analysis in Shanghai, China
Authors: Wang Gang , Cheng Qi , Zheng Rui , Tan Yu‐Yan , Sun Xiao‐Kang , Zhou Hai‐Yan , Ye Xiao‐Lai , Wang Ying , Wang Zeng , Sun Bo‐Min , Chen Sheng‐Di 
Published: June 2006

AbstractWe investigated economic costs from patients with Parkinson's disease (PD) in Shanghai, China, which could be used as a baseline for future evaluations. Data were collected from 190 patients by interview during 1‐year period. Direct medical care costs averaged approximately Chinese yuan, renminbi (RMB) 4,305 (USD 519, or EUR 410) per year per patient, of which drugs (RMB 2,677) accounted for the major costly component. Nonmedical direct costs were much less than direct health care costs, averaging approximately RMB 3,301 (USD 398, or EUR 314). Costs due to loss of productivity averaged approximately RMB 73 (USD 8.8, or EUR 7.0) per patient per year. Taken together, the overall mean annual cost for PD in our series was approximately RMB 7,679 (USD 925, or EUR 731), and these costs accounted for around half of the mean annual income. Total cost was significantly associated with the disease severity and the frequency of outpatient visits. In addition, levodopa equivalent dose (LED) and the number of drugs being taken were also closely related with the drug cost. The results indicate that the economic burden of Chinese PD patients is heavy. © 2006 Movement Disorder Society
Non‐DYT1 early‐onset primary torsion dystonia: Comparison with DYT1 phenotype and review of the literature
Authors: Fasano Alfonso , Nardocci Nardo , Elia Antonio Emanuele , Zorzi Giovanna , Bentivoglio Anna Rita , Albanese Alberto 
Published: June 2006

AbstractTo investigate the clinical features of early‐onset primary torsion dystonia (EO‐PTD), 57 consecutive genetically characterized patients with onset before 21 years were studied. Sex, ethnic origin, family history of dystonia, age at onset, disease duration, site of dystonia onset and distribution at latest examination, dystonia progression, time to generalization, and motor disability were noted. The 14 patients (25%) with GAG deletion (904_906/907_909delGAG) in the DYT1 gene were compared with the remaining non‐DYT1 patients. Cranial involvement was present in 49% of non‐DYT1 cases, but only 14% of DYT1 cases; non‐DYT1 patients were younger at time of generalization. DYT1 cases had features similar to sporadic non‐DYT1 cases but differed markedly from familial non‐DYT1 cases, the latter having later age at onset, less common limb onset, more frequent cervical involvement, and slower progression than DYT1 PTD. These findings indicate that non‐DYT1 forms of EO‐PTD differ clinically from those of DYT1 forms. Cranial involvement before 21 years of age is the strongest predictor of non‐DYT1 status. Positive family history and cervical involvement are associated with less severe progression in non‐DYT1 forms. © 2006 Movement Disorder Society
Dopamine transporters, D2 receptors, and glucose metabolism in corticobasal degeneration
Authors: Klaffke Stefanie , Kuhn Andrea A. , Plotkin Michail , Amthauer Holger , Harnack Daniel , Felix Roland , Kupsch Andreas 
Published: June 2006

AbstractAlterations in presynaptic and postsynaptic dopaminergic system and cerebral glucose metabolism in corticobasal degeneration (CBD) were assessed to evaluate the potential usefulness of different imaging methods for CBD. 123I‐FP‐CIT/123I‐β‐CIT SPECT and 123I‐IBZM SPECT as well as 18F‐FDG PET were performed in eight CBD patients. Decreased presynaptic dopamine transporter binding was found in all CBD patients while D2 receptor binding was reduced in only one patient. 18F‐FDG PET displayed a contralateral hypometabolism in cortical and subcortical areas in seven out of eight patients. Our results demonstrate that glucose metabolism and DAT are reduced, while D2 receptors may be frequently preserved in CBD. © 2006 Movement Disorder Society
Hyperhidrosis in Parkinson's disease
Authors: Schestatsky Pedro , Valls‐Solé Josep , Ehlers João Arthur , Rieder Carlos R.M. , Gomes Irênio 
Published: June 2006

AbstractWe studied the sudomotor skin response (SSR) in patients with Parkinson's disease with and without symptomatic hyperhidrosis. The study was carried out in 13 patients who complained of excessive sweating and in 37 patients who did not have excessive sweating. Patients were matched for age, sex, degree of impairment, duration of the disease, and number and severity of autonomic disturbances. Excessive sweating involved mainly the face, head, and trunk. The SSR was recorded from the palm of the hands to electrical stimulation of the median nerve at the wrist. We analyzed onset latency, peak to peak amplitude, and waveform. Patients with hyperhidrosis had more often absent responses (χ2 = 5.292; P = 0.021), their responses were of lower mean amplitude (analysis of variance [ANOVA]; F[2,101] = 11.678; P < 0.001), and they had a reduced number of responses with a predominantly negative component (χ2 = 8.493; P = 0.004) than patients who did not complain of sweating disturbances. Our results indicate that excessive sweating in Parkinson's disease concurs with decreased activation of sweat glands in the palms of the hands and suggests that axial hyperhidrosis could be a compensatory phenomenon for reduced sympathetic function in the extremities. © 2006 Movement Disorder Society
Retrospective distortion correction for 3D MR diffusion tensor microscopy using mutual information and fourier deformations
Authors: Mistry Nilesh N. , Hsu Edward W. 
Published: June 2006

AbstractMagnetic resonance diffusion tensor imaging (DTI) can be complicated by distortions that contribute to errors in tissue characterization and loss of fine structures. This work presents a correction scheme based on retrospective registration via mutual information (MI), using Fourier transform (FT)‐based deformations to enhance the reliability of the entropy‐based image registration. The registration methodology is applied to correct distortions in 3D high‐resolution DTI datasets, incorporating a complete set of affine deformations. The results demonstrate that the proposed methodology can consistently and significantly reduce the number of misregistered pixels, leading to marked improvement in the visualization of internal brain white matter (WM) structure via DTI. Post‐registration analysis revealed that eddy‐current effects cannot fully account for the observed image distortions. Combined, these findings support the non‐model‐based, postprocessing approach for correcting distortions, and demonstrate the advantages of combining FT‐based deformations and MI registration to enhance the practical utility of DTI. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.
Integral transform solution of internal flow problems based on Navier–Stokes equations and primitive variables formulation
Authors: de Lima G. G. C. , Santos C. A. C. , Haag A. , Cotta R. M. 
Published: June 2006

AbstractThe generalized integral transform technique (GITT) is employed in the solution of incompressible laminar channel flows as formulated by the steady‐state Navier–Stokes and continuity equations under the primitive variables mathematical representation. A hybrid numerical–analytical solution is developed based on eigenfunction expansions in one space co‐ordinate and error‐controlled numerical solution of the resulting system of coupled ordinary differential equations in the remaining space direction. The approach is illustrated for developing flow between parallel‐plates with uniform and irrotational inlet flow condition. The conventional Poisson‐type equation for the pressure field with appropriate boundary conditions is also transformed and simultaneously solved with the momentum equation along the longitudinal direction, by considering eigenvalue problems for each of the two potentials, defined in the transversal direction. The transversal velocity component is then explicitly determined from the continuity equation. Numerical results of the longitudinal velocity component and friction factor fields are reported to illustrate the convergence behaviour and user prescribed error control inherent to the proposed hybrid approach. Critical comparisons with previous contributions on the same method that made use of the streamfunction‐only formulation are also provided. Copyright © 2006 John Wiley & Sons, Ltd.
Generalized coupled thermoelasticity of functionally graded cylindrical shells
Authors: Bahtui A. , Eslami M. R. 
Published: June 2006

AbstractIn this paper, the response of a circular cylindrical thin shell made of the functionally graded material based on the generalized theory of thermoelasticity is obtained. The governing equations of the generalized theory of thermoelasticity and the energy equations are simultaneously solved for a functionally graded axisymmetric cylindrical shell subjected to thermal shock load. Thermoelasticity with second sound effect in cylindrical shells based on the Lord–Shulman model is compared with the Green–Lindsay model. A second‐order shear deformation shell theory, that accounts for the transverse shear strains and rotations, is considered. Including the thermo‐mechanical coupling and rotary inertia, a Galerkin finite element formulation in space domain and the Laplace transform in time domain is used to formulate the problem. The inverse Laplace transform is obtained using a numerical algorithm. The shell is graded through the thickness assuming a volume fraction of metal and ceramic, using a power law distribution. The effects of temperature field for linear and non‐linear distributions across the shell thickness are examined. The results are validated with the known data in the literature. Copyright © 2006 John Wiley & Sons, Ltd.
Enhanced one‐point quadrature shell element for nonlinear applications
Authors: Cardoso Rui P. R. , Yoon Jeong Whan , Valente Robertt A. F. 
Published: June 2006

AbstractThis work is an extension to nonlinear applications of a previously published work (Int. J. Numer. Meth. Engng 2006; 66:214–249) about membrane and transverse shear improvement for one‐point quadrature shell elements. A new formulation based on the enhanced assumed strain method and reduced integration techniques, called iCYSE‐E6 (improved Cardoso and Yoon shell element with 6 enhanced parameters) was suggested by Cardoso et al. to improve membrane and transverse shear performances under the framework of linear applications. It was proven that the proposed linear formulation gives accurate responses, even with extremely coarse meshes. The proposed extension of this work is then performed in such a way that the resulting new finite element can be applied in general simulations with nonlinearities in geometry, material and contact.The interaction among hourglass and enhanced assumed strain stiffness matrices and internal force vectors is taken into account in the present formulation. Special emphasis is given for the construction of nonlinear hourglass terms such that excessive hourglass energy in elastoplastic applications can be controlled efficiently. The finite element matrices are constructed in resultant form, allowing a much simpler and effective formulation for the hourglass terms, and also for the coupling between the constant and the enhanced strain–displacement matrices. It is shown that the present formulation is accurate in demanding problems, even for the cases of relatively large coarse mesh structures. The paper presents several nonlinear examples to assess the element's performance. Copyright © 2006 John Wiley & Sons, Ltd.
Synthesis and characterization of poly(ester ether siloxane)s
Authors: Vuckovic Marija V , Antic Vesna V , Dojcinovic Biljana P , Govedarica Milutin N , Djonlagic Jasna 
Published: June 2006

AbstractA series of novel thermoplastic elastomers based on ABA‐type triblock prepolymers, poly[(propylene oxide)–(dimethylsiloxane)–(propylene oxide)] (PPO‐PDMS‐PPO), as the soft segments, and poly(butylene terephthalate) (PBT), as the hard segments, was synthesized by catalyzed two‐step melt transesterification of dimethyl terephthalate (DMT) with 1,4‐butanediol (BD) and α,ω‐dihydroxy‐(PPO‐PDMS‐PPO) (M̄n = 2930 g mol−1). Several copolymers with a content of hard PBT segments between 40 and 60 mass% and a constant length of the soft PPO‐PDMS‐PPO segments were prepared. The siloxane‐containing triblock prepolymer with hydrophilic terminal PPO blocks was used to improve the compatibility between the polar comonomers, i.e. DMT and BD, and the non‐polar PDMS segments. The structure and composition of the copolymers were examined using 1H NMR spectroscopy, while the effectiveness of the incorporation of α,ω‐dihydroxy‐(PPO‐PDMS‐PPO) prepolymer into the copolyester chains was controlled by chloroform extraction. The effect of the structure and composition of the copolymers on the transition temperatures (Tm and Tg) and the thermal and thermo‐oxidative degradation stability, as well as on the degree of crystallinity, and some rheological properties, were studied. Copyright © 2006 Society of Chemical Industry
Synthesis of amphiphilic copolymer brushes: Poly(ethylene oxide)‐graft‐polystyrene
Authors: Li Zhongyu , Li Pengpeng , Huang Junlian 
Published: June 2006

AbstractA well‐defined amphiphilic copolymer brush with poly(ethylene oxide) as the main chain and polystyrene as the side chain was successfully prepared by a combination of anionic polymerization and atom transfer radical polymerization (ATRP). The glycidol was first protected by ethyl vinyl ether to form 2,3‐epoxypropyl‐1‐ethoxyethyl ether and then copolymerized with ethylene oxide by the initiation of a mixture of diphenylmethylpotassium and triethylene glycol to give the well‐defined polymer poly(ethylene oxide‐co‐2,3‐epoxypropyl‐1‐ethoxyethyl ether); the latter was hydrolyzed under acidic conditions, and then the recovered copolymer of ethylene oxide and glycidol {poly(ethylene oxide‐co‐glycidol) [poly(EO‐co‐Gly)]} with multiple pending hydroxymethyl groups was esterified with 2‐bromoisobutyryl bromide to produce the macro‐ATRP initiator [poly(EO‐co‐Gly)(ATRP). The latter was used to initiate the polymerization of styrene to form the amphiphilic copolymer brushes. The object products and intermediates were characterized with 1H NMR, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry, Fourier transform infrared, and size exclusion chromatography in detail. In all cases, the molecular weight distribution of the copolymer brushes was rather narrow (weight‐average molecular weight/number‐average molecular weight < 1.2), and the linear dependence of ln[M0]/[M] (where [M0] is the initial monomer concentration and [M] is the monomer concentration at a certain time) on time demonstrated that the styrene polymerization was well controlled. This method has universal significance for the preparation of copolymer brushes with hydrophilic poly(ethylene oxide) as the main chain. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4361–4371, 2006
A novel method for the pore size control of the battery separator using the phase instability of the ternary mixtures
Authors: Kim L. U. , Kim C. K. 
Published: June 2006

AbstractThe battery separator plays a key role in determining the capacity of the battery. Since separator performance mainly depends on the pore size of membrane, development of a technique for the fabrication of the membrane having controlled pore size is essential in producing a highly functional battery separator. In this study, microporous membranes having the desired pore size were produced via thermally‐induced phase separation (TIPS) process. Control of the phase boundaries of polymer‐diluent blends is the main concern in manipulating pore size in TIPS process, because pore size mainly depends on the temperature gap between phase separation temperature of the blend and the crystallization temperature of polymer. Microporous membranes having controlled pore size were produced from polyethylene (PE)/dioctyl phthalate (DOP) blends, PE/isoparaffin blends, and polymer/diluent‐mixture ternary blends, that is, PE/(DOP/isoparaffin) blends. PE/DOP binary blends and PE/(DOP/isoparaffin) ternary blends exhibited typical upper critical solution temperature (UCST) type phase behavior, while PE formed a homogeneous mixture with isoparaffin above the crystallization temperature of PE. When the mixing ratio of polymer and diluent‐mixture was fixed, the phase separation temperature of PE/diluent‐mixture blend first increased with increasing DOP content in the diluent‐mixture, went through a maximum centered at about 80 wt % DOP and then decreased. Furthermore, the phase separation temperatures of the PE/diluent‐mixture blends were always higher than that of the PE/DOP blend when diluent‐mixture contained more than or equal to 20 wt % of DOP. Average pore size of microporous membrane prepared from PE/DOP blend and that prepared from PE/isoparaffin blend were 0.17 and 0.07 μm, respectively. However, average pore size of microporous membrane prepared from ternary blends was varied from 0.07 to 0.5 μm by controlling diluent mixing ratio. To understand the phase behavior of ternary blend, phase instability of the ternary mixture was also explored. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2025–2034, 2006