bluuebunny/crossref_metadata_2025_split huggingface dataset:
A single deletion at position 134, 135, or 136 in the beta 7–beta 8 loop of the p51 subunit of HIV‐1 RT disrupts the formation of heterodimeric enzyme
Authors: Upadhyay Alok , Pandey Nootan , Mishra Chaturbhuj A. , Talele Tanaji T. , Pandey Virendra N. 
Published: December 2009

AbstractThe human immunodeficiency virus type 1 reverse transcriptase (HIV‐1 RT) is a heterodimeric enzyme composed of p66 and p51 subunits. Earlier, we showed that the β7–β8 loop of p51 is crucial for polymerase activity of HIV‐1 RT as either deletion or Ala substitution of amino acids in the β7–β8 loop spanning residues 136‐139 in the p51 subunit impaired dimerization and, in turn, polymerase function of the enzyme (Pandey et al. 2001 Biochemistry 40: 9505–9512). In the present study, we generated subunit‐specific single‐deletion mutants at positions 134, 135, 136, or 137 and examined their effects on the heterodimerization, binary complex formation, and polymerase functions of the enzyme. We found that among these four residues, Ser134, Ile135, and Asn136 in the β7–β8 loop of the p51 subunit are crucial residues for dimerization and polymerase function of the enzyme, but have no impact when specifically deleted from the p66 subunit. These results demonstrate the β7–β8 loop of the p51 subunit in the formation of stable, functional heterodimeric enzyme which could be an attractive target for anti‐HIV‐1 drug development. J. Cell. Biochem. 109: 598–605, 2010. © 2009 Wiley‐Liss, Inc.
The ontogeny of Pseudis platensis (Anura, Hylidae): Heterochrony and the effects of larval development on postmetamorphic life
Authors: Fabrezi Marissa , Quinzio Silvia I. , Goldberg Javier 
Published: December 2009

AbstractRecent studies have described the giant tadpole, delayed metamorphic transformations, and absence of postmetamorphic growth of the skeleton of Pseudis Platensis. These features address questions about derived patterns of life cycles and the role of the heterochrony during the metamorphosis in anurans. Using anatomical methods, we provide new data on the development of reproductive, digestive and integument systems, and age inference obtained from ontogenetic series of Pseudis platensis. Our results indicate that at the end of metamorphosis, the adult skin is completely differentiated, including the calcified dermal layer; the testis has seminiferous tubules with spermatogonia, spermatocytes, and spermatids; ovarian sacs present previtellogenic ova; and the adult digestive tract is fully formed. The froglets differ from adults only in being unable to reproduce. The entire life cycle of P. platensis can occur in 4 years. In the first year, larval development, growth to adult size, and gonad differentiation are completed. Long larval development rather than size of the tadpoles seems to be involved in the absence of juvenile stages. J. Morphol., 2010. © 2009 Wiley‐Liss, Inc.
Modulation of vocal fold scar fibroblasts by adipose‐derived stem/stromal cells
Authors: Kumai Yoshihiko , Kobler James B. , Park Hyoungshin , Galindo Marilyn , Herrera Victoria L.M. , Zeitels Steven M. 
Published: December 2009

AbstractObjectives/Hypothesis:To explore whether adipose‐derived stem/stromal cells (ASCs) have therapeutic potential for treating scarred superficial lamina propria through the effects of secreted hepatocyte growth factor (HGF) on scar fibroblasts.Study Design:In vitro study using coculture system.Methods:Scar fibroblasts (SFs) were isolated from ferret vocal folds electrocauterized 2 weeks previously. ASCs were isolated from ferret lipoaspirated subcutaneous abdominal fat. For coculture experiments, the two cell types were combined in Transwell plates for 6 days, followed by 1 or 3 days of monoculture after removing the upper chamber. Assays were then performed on cells and media from the bottom chamber. We measured: 1) the production of hyaluronic acid (HA), collagen and HGF via enzyme‐linked immunosorbent assays, 2) the expression of α‐smooth muscle actin (α‐SMA), 3) cell proliferation, and 4) apoptosis of SFs (2, 3, and 4 via flow cytometry). Other experiments examined the effects of HGF on SFs and the effects of HGF neutralization in the coculture system.Results:Coculture led to significant decreases in SF collagen production (P < .05), cell proliferation (P < .05), and α‐SMA expression (P < .05), whereas HA production increased (P < .05). Coculture also increased HGF secretion from ASCs (P < .05). Neutralization of HGF abolished the inhibitory effects of ASCs on SF collagen synthesis (P < .05).Conclusions:ASCs influence SFs to adopt a less fibrotic profile. It appears that HGF is at least one of the soluble factors responsible for this effect. Implanted ASCs could potentially ameliorate vocal fold scar by acting as long‐term, intrinsic sources of HGF. Laryngoscope, 2010
Impact of thyroidectomy without laryngeal nerve injury on vocal quality characteristics: An objective multiparameter approach
Authors: Van Lierde Kristiane , D'haeseleer Evelien , Wuyts Floris L. , Baudonck Nele , Bernaert Lut , Vermeersch Hubert 
Published: December 2009

AbstractObjectives/Hypothesis:The main purpose of this study was to determine the impact of thyroidectomy on the subjective and objective vocal quality using the Dysphonia Severity Index. It was hypothesized that objective measures of vocal function and other vocal characteristics would change (temporarily or permanently) from the presurgical to the postsurgical conditions, even with the entire preservation of the laryngeal nerve, due to the surgical approach and other influencing factors.Study Design:Prospective study in which 44 subjects were studied before (1 week) and three times post‐thyroidectomy.Methods:Subjective (auditory perceptual evaluation and videolaryngostroboscopy) and objective (aerodynamic, vocal range, acoustic, and Dysphonia Severity Index measurements) assessment techniques were used.Results:Paired samples t test indicated a significant decrease of the highest frequency, the highest intensity, the fundamental frequency, and the Dysphonia Severity Index in the first postoperative condition. When a repeated measures analysis of variance was performed with the pre‐ and all the postoperative moments of evaluation taken into account, no significant difference was noted for any of the objective voice characteristics.Conclusions:After thyroidectomy subjects had a normal perceptual and objective vocal quality corresponding with a Dysphonia Severity Index of 66%, and there is no permanent change of the vocal performance. Moreover, there is no psychosocial handicapping effect of the vocal quality, but immediately post‐thyroidectomy there are more vocal complaints. To what extent thyroidectomy causes (temporary or permanent) alterations of the singing voice in elite vocal performers is subject to further research. Laryngoscope, 2010
Green's function expansion for exponentially graded elasticity
Authors: Sallah Omar M. , Gray L. J. , Amer M. A. , Matbuly M. S. 
Published: December 2009

AbstractNew computational forms are derived for Green's function of an exponentially graded elastic material in three dimensions. By suitably expanding a term in the defining inverse Fourier integral, the displacement tensor can be written as a relatively simple analytic term, plus a single double integral that must be evaluated numerically. The integration is over a fixed finite domain, the integrand involves only elementary functions, and only low‐order Gauss quadrature is required for an accurate answer. Moreover, it is expected that this approach will allow a far simpler procedure for obtaining the first and second‐order derivatives needed in a boundary integral analysis. The new Green's function expressions have been tested by comparing with results from an earlier algorithm. Copyright © 2009 John Wiley & Sons, Ltd.
Decoupling and balancing of space and time errors in the material point method (MPM)
Authors: Steffen Michael , Kirby Robert M. , Berzins Martin 
Published: December 2009

AbstractThe material point method (MPM) is a computationally effective particle method with mathematical roots in both particle‐in‐cell and finite element‐type methods. The method has proven to be extremely useful in solving solid mechanics problems involving large deformations and/or fragmentation of structures, problem domains that are sometimes problematic for finite element‐type methods. Recently, the MPM community has focused significant attention on understanding the basic mathematical error properties of the method.Complementary to this thrust, in this paper we show how spatial and temporal errors are typically coupled within the MPM framework. In an attempt to overcome the challenge to analysis that this coupling poses, we take advantage of MPM's connection to finite element methods by developing a ‘moving‐mesh’ variant of MPM that allows us to use finite element‐type error analysis to demonstrate and understand the spatial and temporal error behaviors of MPM. We then provide an analysis and demonstration of various spatial and temporal errors in MPM and in simplified MPM‐type simulations.Our analysis allows us to anticipate the global error behavior in MPM‐type methods and allows us to estimate the time‐step where spatial and temporal errors are balanced. Larger time‐steps result in solutions dominated by temporal errors and show second‐order temporal error convergence. Smaller time‐steps result in solutions dominated by spatial errors, and hence temporal refinement produces no appreciative change in the solution. Based upon our understanding of MPM from both analysis and numerical experimentation, we are able to provide to MPM practitioners a collection of guidelines to be used in the selection of simulation parameters that respect the interplay between spatial (grid) resolution, number of particles and time‐step. Copyright © 2009 John Wiley & Sons, Ltd.
Quality improvement of non‐manifold hexahedral meshes for critical feature determination of microstructure materials
Authors: Qian Jin , Zhang Yongjie , Wang Wenyan , Lewis Alexis C. , Qidwai M. A. Siddiq , Geltmacher Andrew B. 
Published: December 2009

AbstractThis paper describes a novel approach to improve the quality of non‐manifold hexahedral meshes with feature preservation for microstructure materials. In earlier works, we developed an octree‐based isocontouring method to construct unstructured hexahedral meshes for domains with multiple materials by introducing the notion of material change edge to identify the interface between two or more materials. However, quality improvement of non‐manifold hexahedral meshes is still a challenge. In the present algorithm, all the vertices are categorized into seven groups, and then a comprehensive method based on pillowing, geometric flow and optimization techniques is developed for mesh quality improvement. The shrink set in the modified pillowing technique is defined automatically as the boundary of each material region with the exception of local non‐manifolds. In the relaxation‐based smoothing process, non‐manifold points are identified and fixed. Planar boundary curves and interior spatial curves are distinguished, and then regularized using B‐spline interpolation and resampling. Grain boundary surface patches and interior vertices are improved as well. Finally, the optimization method eliminates negative Jacobians of all the vertices. We have applied our algorithms to two beta titanium data sets, and the constructed meshes are validated via a statistics study. Finite element analysis of the 92‐grain titanium is carried out based on the improved mesh, and compared with the direct voxel‐to‐element technique. Copyright © 2009 John Wiley & Sons, Ltd.
Transition states in Ei reactions
Authors: Kingsbury Charles A. 
Published: December 2009

AbstractThe pyrolysis of amine oxides, sulfoxides, selenoxides, and esters to form alkenes is believed to be a concerted reaction with a cyclic transition state. Phosphine oxides, sulfones, and nitro compounds are unreactive. This study seeks to identify reasons for the lack of reactivity of the latter. Transition states were located for all substrates progressing from RHF/3‐21G* to the MP2/6‐31+G(d,p) level (in certain cases). For sulfones and nitro compounds, two possible reasons for lack of reactivity were considered: (1) Atoms approaching one another in the transition state may be considered to participate in a local nO → σ*CHinteraction. The second oxygen in the sulfone or nitro compound lowers the energy of the ‘non‐bonded electrons’ at oxygen leading to a greater mismatch in energy with the antibonding CH orbital (in comparison to the sulfoxide or amine oxide). (2) The sulfone and nitro ‘lone pairs’ are not really ‘alone’, and available to react. In fact, complex bonding arrangements exist in the SO2and NO2groups. The situation is less clear for phosphine oxides, although ground state stability of bonds is important. Implications concerning the Hammond postulate are covered. Copyright © 2009 John Wiley & Sons, Ltd.
Antitumor and antiplatelet activity of alkaloids from veratrum dahuricum
Authors: Tang Jian , Li Hui‐Liang , Shen Yun‐Heng , Jin Hui‐Zi , Yan Shi‐Kai , Liu Xiao‐Hua , Zeng Hua‐Wu , Liu Run‐Hui , Tan Ye‐Xiong , Zhang Wei‐Dong 
Published: December 2009

AbstractTen steroidal alkaloids – cyclopamine, veratramine, jervine, 3, 15‐diangyloylgermine, 3‐angyloylzygadenine, 3‐veratroyl zygadenine, 15‐veratroylgermine, germine, veratrosine and pseudojervine – from Veratrum dahuricum, together with the ethanol extract and total alkaloids, were evaluated for their antitumor and antiplatelet activities. Cyclopamine, veratramine and germine significantly inhibited the hedgehog pathway in NIH/3T3 cells. Cyclopamine exerted a potent inhibitory effect against the growth of PANC‐1 tumors in mice, with inhibition rates of 40.64%, 44.37%, 46.77% at doses of 5.0, 15.0 and 50.0 mg kg‐1, respectively. Veratroylgermine was found to produce the strongest inhibition against the platelet aggregation induced by arachidonic acid, with inhibition rate of 92.0% at 100 μM. Copyright © 2009 John Wiley & Sons, Ltd.
Mechanisms underlying vascular effect of chronic resveratrol in streptozotocin‐diabetic rats
Authors: Roghani Mehrdad , Baluchnejadmojarad Tourandokht 
Published: December 2009

AbstractIn this study, some underlying mechanisms responsible for the beneficial effect of chronic oral administration of resveratrol on aortic reactivity of streptozotocin (STZ)‐diabetic rats were investigated. Male diabetic rats received resveratrol (10 mg/kg/day) for 8 weeks, 1 week after diabetes induction. Treatment of diabetic rats with resveratrol produced a hypoglycaemic effect and there were appropriate changes regarding serum lipids. Resveratrol also attenuated the increased malondialdehyde (MDA) content and reduced activity of superoxide dismutase (SOD) in liver and aortic tissues. Maximum contractile response of endothelium‐intact aortic rings to KCl and phenylephrine (PE) was significantly lower in resveratrol‐treated diabetic rats relative to untreated diabetics. Endothelium removal abolished the significant difference between resveratrol‐treated and untreated diabetic groups regarding contractile response to KCl and PE. Meanwhile, endothelium‐dependent relaxation to acetylcholine (ACh) was significantly higher in resveratrol‐treated diabetic rats as compared to diabetic group and pretreatment with N(omega)‐L‐arginine methyl ester (L‐NAME) and indomethacin (INDO) significantly attenuated these responses. Chronic treatment with resveratrol may prevent diabetes‐related changes in vascular reactivity observed in diabetic rats directly and/or indirectly due to its hypoglycaemic and hypolipidaemic effects and attenuation of lipid peroxidation and through endothelial‐derived factors. Copyright © 2009 John Wiley & Sons, Ltd.
Antiproliferative and proapoptotic actions of okra pectin on B16F10 melanoma cells
Authors: Vayssade Muriel , Sengkhamparn Nipaporn , Verhoef René , Delaigue Claire , Goundiam Oumou , Vigneron Pascale , Voragen Alphons G.J. , Schols Henk A. , Nagel Marie‐Danielle 
Published: December 2009

AbstractThe proliferation and apoptosis of metastatic melanoma cells are often abnormal. We have evaluated the action of a pectic rhamnogalacturonan obtained by hot buffer extraction of okra pods (okra RG‐I) on melanoma cell growth and survival in vitro. We added okra RG‐I containing an almost pure RG‐I carrying very short galactan side chains to 2D (on tissue culture polystyrene, tPS) and 3D (on poly(2‐hydroxyethylmethacrylate), polyHEMA) cultures of highly metastatic B16F10 mouse melanoma cells. We then analyzed cell morphology, proliferation index, apoptosis, cell cycle progression and the expression of adhesion molecules. Immunostaining and western blotting were used to assay galectin‐3 (Gal‐3) protein.Incubation with okra RG‐I altered the morphology of B16F10 cells and significantly reduced their proliferation on both tPS and polyHEMA. The cell cycle was arrested in G2/M, and apoptosis was induced, particularly in cells on polyHEMA. The expression of N‐cadherin and α5 integrin subunit was reduced and that of the multifunctional carbohydrate‐binding protein, Gal‐3, at the cell membrane increased.These findings suggest that okra RG‐I induces apoptosis in melanoma cells by interacting with Gal‐3. As these interactions might open the way to new melanoma therapies, the next step will be to determine just how they occur. Copyright © 2009 John Wiley & Sons, Ltd.
Hypotensive effect of aqueous saffron extract (Crocus sativus L.) and its constituents, safranal and crocin, in normotensive and hypertensive rats
Authors: Imenshahidi Mohsen , Hosseinzadeh Hossein , Javadpour Yaser 
Published: December 2009

AbstractIn this study, the effects of saffron (Crocus sativus) stigma aqueous extract and two active constituents, crocin and safranal, were investigated on blood pressure of normotensive and desoxycorticosterone acetate‐induced hypertensive rats. Three doses of crocin (50, 100 and 200 mg/kg), safranal (0.25, 0.5 and 1 mg/kg) and the aqueous extract (2.5, 5 and 10 mg/kg) were administered intravenously in different groups of normotensive and hypertensive animals and their effects on mean arterial blood pressure (MABP) and heart rate (HR) were evaluated. The aqueous extract of saffron stigma, safranal and crocin reduced the MABP in normotensive and hypertensive anaesthetized rats in a dose‐dependent manner. For example, administrations of 10 mg/kg of aqueous extract, 1 mg/kg of safranal and 200 mg/kg of crocin caused 60 ± 8.7, 50 ± 5.2 and 51 ± 3.8 mmHg reductions in MABP, respectively. It can be concluded that the aqueous extract of saffron stigma has hypotensive properties which appear to be attributable, in part, to the actions of two major constitutes of this plant, crocin and safranal. It seems that safranal is more important than crocin for lowering down blood pressure of rats. Copyright © 2009 John Wiley & Sons, Ltd.
Randomized double‐blind placebo‐controlled trial on the potential modes of action of sheaflex70tm in osteoarthritis
Authors: Cheras Phillip A. , Myers Stephen P. , Paul‐Brent Peta‐Anne , Outerbridge Kerry H. , Nielsen Gary V. L. 
Published: December 2009

AbstractExtracts from the seed of the African shea tree Vitellaria paradoxa C.F. Gaertn have been used traditionally for the treatment of arthritic conditions. However, little is known about the mechanisms by which benefit is conferred. This single‐site, 15‐week randomized, double‐blind, parallel, placebo‐controlled study examined a range of biomarkers in 89 patients with osteoarthritis of the knees and/or hips to determine potential modes of action of SheaFlex70TM, a triterpene‐rich extract of Vitellaria paradoxa. In the group of participants with levels of osteoarthritis biomarkers in the upper quartile at baseline, there were significant decreases in inflammation and cartilage breakdown and trend level decreases in bone remodeling in the SheaFlex70TM group versus placebo between commencement and completion of the study. Inflammation marker TNF‐alpha fell 23.9% vs 6% (treatment vs placebo), p = 0.041. Cartilage degradation marker CTX‐II fell 28.7% vs an increase of 17.6% (treatment vs placebo), p = 0.018. This marker also showed significant falls across the entire study group, 10.6% vs an increase of 11.6%, (treatment vs placebo), p = 0.016. Osteocalcin levels fell 9.2%, p = 0.014 (treatment) vs 1.2%, ns (placebo), p = 0.096 (treatment vs placebo). These findings indicate that in patients with the highest levels of osteoarthritis biomarkers, SheaFlex70TM demonstrated multiple beneficial activities consistent with slowing the disease process. Copyright © 2009 John Wiley & Sons, Ltd.
Nonadditive nature of nucleobases interactions in model d(GpG) dinucleotide steps
Authors: Cysewski Piotr 
Published: December 2009

AbstractHigh nonadditive character of intermolecular interaction energy (IIE) has been found for many d(GpG) dinucleotide steps in B‐DNA conformations. Although three‐ and four‐body terms posses opposite signs in all cases, positive nonadditivity is observed. On the other hand, the pairwise additive simplification may still be applied because there is linear correlation between magnitude of additive and nonadditive terms of IIE. The application of the linear regression leads to a higher accuracy with values of standard deviation about 0.5 kcal/mol. The heterogeneity of intermolecular interactions in two subsequent GC pairs was identified as the main source of nonadditivity. The higher the difference between hydrogen bonding and interstrand stacking, the higher the absolute values of three‐ and four‐body terms. This trend is of linear character and may be used for both parametric correction and measure of nonadditivity in d(GpG) steps without necessity of energy calculations for the whole tetramer. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Nonlinear predictive control of smooth nonlinear systems based on Volterra models. Application to a pilot plant
Authors: Gruber Jorn K. , Bordons Carlos , Bars Ruth , Haber Robert 
Published: December 2009

AbstractThere is a large demand to apply nonlinear algorithms to control nonlinear systems. With algorithms considering the process nonlinearities, better control performance is expected in the whole operating range than with linear control algorithms. Three predictive control algorithms based on a Volterra model are considered. The iterative predictive control algorithm to solve the complete nonlinear problem uses the non‐autoregressive Volterra model calculated from the identified autoregressive Volterra model. Two algorithms for a reduced nonlinear optimization problem are considered for the unconstrained case, where an analytic control expression can be given. The performance of the three algorithms is analyzed and compared for reference signal tracking and disturbance rejection. The algorithms are applied and compared in simulation to control a Wiener model, and are used for real‐time control of a chemical pilot plant. Copyright © 2009 John Wiley & Sons, Ltd.
An iris recognition model for secured access to data
Authors: El Khoury Franjieh , Egea Marcel , Meskaoui Nada , Wakim Nagi 
Published: December 2009

AbstractThe exponential growth in the usage of the Internet as well as the emergence of advanced applications, increase the risk of unauthorized access to confidential information. For the last few years, biometric techniques, especially the ones related to iris recognition, have proven their reliability in providing secure access to shared resources in different domains. Many algorithms have been proposed for implementing the iris recognition biometric techniques. In this paper, we study and compare these proposals and propose an efficient new algorithm for iris recognition. Copyright © 2009 John Wiley & Sons, Ltd.