bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proteomics study of anthrax lethal toxin‐treated murine macrophages
Authors: Kuhn Jeffrey F. , Hoerth Patric , Hoehn Silvia T. , Preckel Tobias , Tomer Kenneth B. 
Published: April 2006

AbstractThe anthrax lethal toxin (LeTx) is composed of two proteins, protective antigen and lethal factor, which bind and enter the cell through a host receptor termed the anthrax toxin receptor (ATR). In the cell, LeTx targets p38, part of the MAP kinase signaling pathway. The toxin appears to initiate an apoptotic pathway in infected cells, indicating additional downstream targets of the toxin. We have applied a proteomics approach to investigate these downstream targets and the affected processes. In this study we have used an improved strategy for fractionation based on protein pI, off‐gel electrophoresis, employed in conjunction with relative quantitation using the mass labeling approach. In our survey, 67 proteins were observed and quantified from the cytosol of RAW 264.7 cells with respect to control versus toxin‐treated cells. Many of these proteins are involved in the oxidative stress response, as well as apoptosis, and thus likely to be relevant to the effects of anthrax in infected cells. Our results indicate that the tumor necrosis factor‐α‐mediated pathway is compromised in intoxicated cells. The knowledge of such changes and the pathways leading to the changes should be of great value in understanding and combating this disease.
Tetrabutylammonium salt of the B24F224− anion. Two B12F112− icosahedra linked by a 2c–2e BB bond and surrounded by a sheath of CH· · ·FB hydrogen bonds
Authors: Kobayashi Yoshihiro , Ivanov Sergei V. , Popov Alexey A. , Miller Susie M. , Anderson Oren P. , Solntsev Konstantin A. , Strauss Steven H. 
Published: April 2006

AbstractThe B24F224− anion, which was formed as a minor by‐product when the B12H122− anion was treated with F2 in liquid HF, has been isolated as its N(n‐Bu)4+ salt and characterized by 10B, 11B, and 19F NMR spectroscopy, electrospray mass spectrometry, cyclic voltammetry, single‐crystal X‐ray diffraction, and calculations at the DFT level of theory. The B24F224− anion has idealized D5 symmetry and consists of two B12F112− icosahedra linked by a 2c–2e boron–boron single bond with a BB distance of 1.725(4) Å. In the solid state, the anion interacts with eight N(n‐Bu)4+ cations via a network of 34 CH···FB hydrogen bonds with H· · ·F distances that range from 2.26 to 2.55 Å. These hydrogen bonds were successfully modeled by DFT calculations, which showed that the hydrogen bonds probably have a measurable, albeit subtle, effect on the structure of the B24F224−. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:181–187, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20220
Expression of the angiomatrix and angiogenic proteins CYR61, CTGF, and VEGF in osteonecrosis of the femoral head
Authors: Radke S. , Battmann A. , Jatzke S. , Eulert J. , Jakob F. , Schütze N. 
Published: April 2006

AbstractAngiogenesis and bone repair are closely linked processes. VEGF, CYR61, and CTGF have been identified as signaling factors that control angiogenesis and could be important in fracture healing. The purpose of this study was to investigate the expression of these signaling factors in osteonecrosis of the femoral head. Twenty‐one bone cylinders were retrieved from hips of patients with osteonecrosis of the femoral head at different ARCO stages. Immunohistochemistry for CD34, CYR61, CTGF, and VEGF expression was done on each bone cylinder representing the different regions of osteonecrosis (necrosis, fibrosis, transition zone, and edematous area). VEGF, CYR61, and CTGF were expressed in samples with osteonecrosis. Particularly VEGF and CYR61 were highly expressed in the edematous area. CYR61 was also highly expressed in the transition zone. CTGF was expressed mainly in the area of marrow fibrosis and edema. CYR61, CTGF, and VEGF are expressed to different degrees in the different repair zones of osteonecrosis. Particularly, the high expression of VEGF and CYR61 in the edematous area may represent a consequence of hypoxia and indicate a role of these proteins in the repair processes ongoing in osteonecrosis. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Regional gene therapy for full‐thickness articular cartilage lesions using naked DNA with a collagen matrix
Authors: Di Cesare Paul E. , R. Frenkel Sally , Carlson Cathy S. , Fang Carrie , Liu Chuanju 
Published: April 2006

AbstractA novel gene therapy approach for treating damaged cartilage is proposed that involves placing endotoxin‐free cDNA containing the gene for bone morphogenetic protein‐2 (BMP‐2) in type I collagen sponges and then transferring the naked plasmid DNA construct to the injury site. A full‐thickness cartilaginous defect in rabbits implanted with plasmid containing a marker gene (β‐galactosidase) showed expressed protein as detected by immunostaining. At 1 week postimplantation, mesenchymal cells subjacent to the defect had incorporated the implanted naked plasmid DNA and, once transfected, served as local bioreactors, transiently producing the gene product. Plasmids containing the gene for BMP‐2 implanted in collagen sponges in cartilage lesions stimulated hyalinelike articular cartilage repair at 12 weeks postimplantation, nearly equivalent in quality to that induced by collagen sponges with recombinant BMP‐2 protein. Our approach circumvents the risks of inflammation and immunogenic response associated with the use of viral vectors. Naked plasmid DNA as a vehicle for transferring therapeutic genes has been shown to be effective in a therapeutic model within rabbit articular cartilage and appears to be safe and cost effective. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Density and structural changes in the bone of growing rats after weekly alendronate administration with and without a methotrexate challenge
Authors: Spadaro J.A. , Damron T.A. , Horton J.A. , Margulies B.S. , Murray G.M. , Clemente D.A. , Strauss J.A. 
Published: April 2006

AbstractAlendronate (ALN) and other bisphosphonates have been used successfully in pediatric patients with osteopenia secondary to connective tissue diseases. Loss of growth in height has not been reported, but concerns remain regarding the effect of these potent antiresorptive agents when used in children and adolescents. High‐dose methotrexate (MTX) and other chemotherapy drugs have been implicated in osteoporosis and a high fracture incidence in survivors of childhood cancers and are also associated with osteopenia in adult animals. The effect of high dose MTX on bone densityduring rapid skeletal growth, however, has not been widely studied, nor has the potentially therapeutic effect of bisphosphonates in this setting. We examined the effects of ALN and MTX administration, alone and in combination, on bone density, morphology, mechanical strength, and longitudinal growth in normal growing rats. Sprague‐Dawley rats were given ALN once weekly (0.3 mg/kg) from 5 to 11 weeks of age, with and without a course of methotrexate (MTX) given daily in weeks 1 and 3 (0.75 mg/kg/day). Twenty‐four animals were randomly divided into four groups: Control (vehicle), ALN alone, ALN + MTX, and MTX alone. After 6 weeks, the femora, tibiae, and lumbar spine were studied by dual‐energy X‐ray absorptiometry, peripheral quantitative computed tomography, mechanical strength testing, microradiography, light microscopy, and by determination of ash weights and bone lengths. ALN treatment increased bone mineral density (BMD) by 23% to 68%. The largest increases in the femur occurred in the distal third where endochondral bone growth was greatest and included large increases in trabecular bone and total cross‐sectional area. ALN + MTX produced similar effects to ALN alone. MTX only reduced BMD by 8% in the vertebrae, but not significantly at other sites. MTX also led to femoral length reductions of 2.9%. The small reductions in BMD due to MTX were overwhelmed by the increases due to ALN, whereas the length loss was unaffected. Transverse density banding corresponding to weekly ALN administrations were clearly evident radiographically throughout the growing skeleton, likely due to decreased resorption and possibly increased mineralization in the bands. ALN or ALN + MTX treatment also led to increases in mechanical strength in the femora. Although MTX administration during growth leads to some BMD reduction, ALN given with MTX eliminates this reduction and in fact bone density and strength increase above control levels. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
N‐bromosuccinimide oxidation of dipeptides and their amino acids: Synthesis, kinetics and mechanistic studies
Authors: Gowda N. S. Linge , Kumara M. N. , Gowda D. Channe , Rangappa K. S. 
Published: April 2006

AbstractDipeptides (DP), namely valyl–glycine (Val–Gly), alanyl–proline (Ala–Pro), and valyl–proline (Val–Pro) were synthesized by classical solution phase methods and characterized. The kinetics of oxidation of amino acids (AA) and DP by N‐bromosuccinimide (NBS) was studied in the presence of perchlorate ions in acidic medium at 28°C. The reaction was followed spectrophotometrically at λmax = 240 nm. The reactions follow identical kinetics, being first order each in [NBS], [AA], and [DP]. No effect on [H+], reduction product [succinimide], and ionic strength was observed. Effects of varying dielectric constant of the medium and addition of anions such as chloride and perchlorate were studied. Activation parameters have been computed. The oxidation products of the reaction were isolated and characterized. The proposed mechanism is consistent with the experimental results. An apparent correlation was noted between the rate of oxidation of AA and DP. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 376–385, 2006
Kinetic study of the reactions of atomic chlorine with several volatile organic compounds at 240–340 K
Authors: Li Zhuangjie , Pirasteh Ali 
Published: April 2006

AbstractThe rate constant for the reactions of atomic chlorine with 1,4‐dioxane (k1), cyclohexane (k2), cyclohexane‐d12(k3), and n‐octane (k4) has been determined at 240–340 K using the relative rate/discharge fast flow/mass spectrometer (RR/DF/MS) technique developed in our laboratory. Essentially, no temperature dependence for these reactions was observed over this temperature range, with an average of k1 = (1.91 ± 0.20) × 10−10 cm3 molecule−1 s−1, k2 = (2.91 ± 0.31) × 10−10 cm3 molecule−1 s−1, k3 = (2.73 ± 0.30) × 10−10 cm3 molecule−1 s−1, and k4 = (3.22 ± 0.36) × 10−10 cm3 molecule−1 s−1, respectively. The kinetic isotope effect of the reaction of cyclohexane with atomic chlorine has also been determined to be 1.14 by directly monitoring the decay of both cyclohexane and cyclohexane‐d12 in the presence of chlorine atoms, which is consistent with the literature value of 1.20. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 386–398, 2006
Carbothermal synthesis of vanadium nitride: Kinetics and mechanism
Authors: Ortega A. , Roldan M. A. , Real C. 
Published: April 2006

AbstractConstant rate thermal analysis (CRTA) has been used for the first time to study the kinetics of the carbothermal reduction of V2O5 in nitrogen to obtain vanadium nitride. It is noteworthy to point out that CRTA method allows both a good control of pressure in the sample surroundings and the use of reaction rates low enough to keep temperatures gradients at a negligible level to avoid any heat or mass transfer phenomena. This method allows one to control the texture and the structure of many materials through kinetic control of the thermal treatment of the precursors. The precise control of the external parameters of the reaction shows that CRTA is an attractive method for kinetic studies and leads to more reliable kinetic data. It has been shown that the carbothermal synthesis of vanadium nitride is best described by a three‐dimensional diffusion kinetic model (the Jander equation) with an activation energy which falls in the range of 520–540 kJ/mol. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 369–375, 2006
Structure determination of ursene‐type triterpenes by NMR techniques
Authors: Ahmed Zaheer , Ali Dildar , Malik Abdul 
Published: April 2006

AbstractTwo new ursene‐type triterpenes, nudicauline A and nudicauline B, have been isolated from Launaea nudicaulis. Their structures have been assigned as 3β‐hydroxy‐urs‐11‐ene (1) and 3β‐acetyl‐urs‐11‐ene (2), respectively, by extensive NMR studies. In addition, olean‐11,13(18)‐diene (3), 3β‐hydroxy‐13(28)‐epoxy‐urs‐11‐ene (4) and 3‐keto‐13(28)‐epoxy‐urs‐11‐ene (5) are also reported for the first time from this species. Copyright © 2006 John Wiley & Sons, Ltd.
Nonempirical calculations of NMR indirect spin–spin coupling constants. Part 15: pyrrolylpyridines
Authors: Rusakov Yury Yu. , Krivdin Leonid B. , Schmidt Elena Yu. , Mikhaleva Albina I. , Trofimov Boris A. 
Published: April 2006

AbstractConformational study of 2‐(2‐pyrrolyl)pyridine and 2,6‐di(2‐pyrrolyl)pyridine was performed on the basis of the experimental measurements and high‐level ab initio calculations of the one‐bond 13C–13C, 13C–1H and 15N–1H spin–spin coupling constants showing marked stereochemical behavior upon the internal rotation around the pyrrole–pyridine interheterocyclic bonds. Both compounds were established to adopt predominant s‐cis conformations with no noticeable out‐of‐plane deviations. Copyright © 2006 John Wiley & Sons, Ltd.
MGMT promoter methylation correlates with survival benefit and sensitivity to temozolomide in pediatric glioblastoma
Authors: Donson Andrew M. , Addo‐Yobo Steven O. , Handler Michael H. , Gore Lia , Foreman Nicholas K. 
Published: April 2006

AbstractBackgroundMethylation of the DNA‐repair gene O6‐methylguanine‐DNA methyltransferase (MGMT) causes gene silencing. This epigenetic modification has been associated with a favorable prognosis in adult patients with glioblastoma (GBM) who receive temozolomide and other alkylating agents. We explored MGMT promoter methylation in pediatric GBM and its relationship to survival and temozolomide sensitivity.ProcedureWe performed a retrospective study of MGMT promoter methylation in 10 pediatric GBM. The methylation status of the MGMT was determined using a 2‐stage methylation specific PCR analysis on DNA extracted from tumor specimens which had been snap frozen at surgery. The relationships between MGMT promoter methylation and patient outcome and response to temozolomide were evaluated.ResultsFour of our 10 pediatric patients with GBM were found to have methylation of the MGMT gene promoter. Methylation of the MGMT promoter was shown to correlate (P = 0.0005) with survival. The average survival time for patients with methyltated MGMT was 13.7 months as compared to 2.5 months for the 6 patients with unmethylated MGMT promoter. Of the seven patients that received temozolomide, those patients that had the methylated MGMT gene promoter responded better to treatment (P = 0.007).ConclusionsAs in adults, pediatric GBM patients with methylated MGMT promoter benefited from temozolomide. However, a stronger correlation with overall survival, regardless of treatment, was observed in this group of patients. These data suggest that MGMT methylation may be a prognostic factor for survival in pediatric GBM, as well as a marker for temozolomide sensitivity. Pediatr Blood Cancer © 2006 Wiley‐Liss, Inc.
Aggregation of poly(1,3‐cyclohexadiene): Effects of molecular weight and polymer chain structure
Authors: Natori Itaru , Sato Hisaya 
Published: April 2006

AbstractThe aggregation of poly(1,3‐cyclohexadiene) (PCHD), obtained by anionic polymerization with alkyllithium/amine systems, was examined using size exclusion chromatography (SEC) and size exclusion chromatography coupled with a multiangle laser light scattering photometer (SEC‐MALS). The PCHD polymer chain has a structure consisting of a main chain formed by 1,2‐addition (the 1,2‐CHD unit) and 1,4‐addition (the 1,4‐CHD unit). Mild stirring with relatively low temperature in the polymerization reaction forms an aggregation of PCHD. The molecular weight and molar ratio of 1,2‐CHD/1,4‐CHD units in the polymer chain strongly influence the aggregation of PCHD. In a high molecular weight PCHD, containing ∼50% 1,2‐CHD units, an aggregation of the polymer was observed in tetrahydrofuran (THF) solution at room temperature. This aggregation of PCHD was soluble in 1,2,4‐trichlorobenzene (TCBz) and could be separated into each polymer molecule. In contrast, a polymer chain with a high content of 1,4‐CHD units having a relatively low cis‐stereospecificity was easily soluble in THF and TCBz without aggregating. A long polymer chain structure with a high content of 1,2‐CHD units is considered to be the reason for the generation of strong intermolecular forces contributing to the aggregation of PCHD with the solvophobic interactions. The degree of aggregation could be controlled by the conditions of the PCHD polymer solution. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1442–1452, 2006
Tensile behavior of Nafion and sulfonated poly(arylene ether sulfone) copolymer membranes and its morphological correlations
Authors: Liu Dan , Kyriakides Steven , Case Scott W. , Lesko John J. , Li Yanxiang , McGrath James E. 
Published: April 2006

AbstractThe tensile stress–strain behavior of Nafion 117 and sulfonated poly(arylene ether sulfone) copolymer (BPSH35) membranes were explored with respect to the effects of the strain rate, counterion type, molecular weight, and presence of inorganic fillers. The yielding properties of the two films were most affected by the change in the strain rate. The stress–strain curves of Nafion films in acid and salt forms exhibited larger deviations at strains above the yield strain. As the molecular weight of the BPSH35 samples increased, the elongation at break improved significantly. Enhanced mechanical properties were observed for the composite membrane of BPSH35 and zirconium phenylphosphonate (2% w/w) in comparison with its matrix BPSH35 film. The stress‐relaxation behavior of Nafion and BPSH35 membranes was measured at different strain levels and different strain rates. Master curves were constructed in terms of plots of the stress‐relaxation modulus and time on a double‐logarithm scale. A three‐dimensional bundle‐cluster model was proposed to interpret these observations, combining the concepts of elongated polymer aggregates, proton‐conduction channels, and states of water. The rationale focused on the polymer bundle rotation/interphase chain readjustment before yielding and polymer aggregate disentanglements and reorientation after yielding. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1453–1465, 2006
From toric geometry to quiver gauge theory: The equivalence of a‐maximization and Z‐minimization
Authors: Butti A. , Zaffaroni A. 
Published: April 2006

AbstractAdS/CFT predicts a precise relation between the central charge a, the scaling dimensions of some operators in the CFT on D3‐branes at conical singularities and the volumes of the horizon and of certain cycles in the supergravity dual. We review how this quantitative check can be performed for all toric singularities. We discuss how these results are related to the recently discovered map between toric singularities and tilings; in particular, we discuss how to find the precise distribution of R‐charges in the quiver gauge theory using dimers technology.
Chronology protection in AdS/CFT
Authors: Caldarelli M.M. 
Published: April 2006

AbstractWe review the issue of chronology protection and show how string theory can solve it in the half BPS sector of AdS/CFT. According to the LLM prescription, half BPS excitations of AdS5 × 𝒮5 geometries in type IIB string theory can be mapped into free fermion configurations. We show that unitarity of the theory describing these fermions is intimately related to the protection of the chronology in the dual geometries.
Fluxes, moduli fixing and MSSM‐like vacua in type IIA string theory
Authors: Cámara P.G. 
Published: April 2006

AbstractWe review some of the features of Type IIA compactifications in the presence of fluxes. In particular, the case of T6/(Ω (‐1) σ) orientifolds with RR, NS and metric fluxes is considered. This has revealed to possess remarkable properties such as vacua with all the closed string moduli stabilized, null or negative contributions to the RR tadpoles or supersymmetry on the branes enforced by the closed string background. In this way, Type IIA compactifications with non trivial fluxes seem to constitute a new window into the building of semi‐realistic models in String Theory.
ZZ‐branes from a spacetime perspective
Authors: Cirafici M. 
Published: April 2006

AbstractWe review the analysis of the tachyon and RR scalar spacetime field configurations sourced by the (m, n) ZZ D‐branes in type 0 theories. We focus on three approaches: the mini‐superspace approximation, a motivated ansatz to go beyond the semi‐classical approximation and finally by using the FZZT branes as probes. In all the three methods we find that the tension of the (m, n) ZZ brane is m n times the tension of the (1,1) ZZ brane. The RR charge of these branes is non‐zero only for the case of both m and n odd, in which case it is identical to the charge of the (1,1) brane.
The spinorial method of classifying supersymmetric backgrounds
Authors: Gran U. , Gutowski J. , Papadopoulos G. , Roest D. 
Published: April 2006

AbstractWe review how the classification of all supersymmetric backgrounds of IIB supergravity can be reduced to the evaluation of the Killing spinor equations and their integrability conditions, which contain the field equations, on five types of spinors. This is an extension of the work [hep‐th/0503046] to IIB supergravity. By using the explicit expressions for the Killing spinor equations evaluated on the five types of spinors the Killing spinor equations become a linear system in terms of the fluxes, the geometry and the spacetime derivatives of the functions that determine the Killing spinors. This system can be solved to express the fluxes in terms of the geometry and to determine the conditions on the geometry of any supersymmetric background. Similarly, the integrability conditions of the Killing spinor equations are turned into a linear system. This can be used to determine the field equations that are implied by the Killing spinor equations for any supersymmetric background. These linear systems simplify for generic backgrounds with maximal and half‐maximal number of H‐invariant Killing spinors, H ⊂ Spin(9,1). In the maximal case, the Killing spinor equations factorise, whereas in the half‐maximal case they do not.
Vertex algebras and conformal field theory models in four dimensions
Authors: Todorov I. 
Published: April 2006

AbstractThe notion of global conformal invariance (GCI) in Minkowski space allows to prove rationality of correlation functions and to extend the concept of vertex algebra to any number D of space‐time dimensions. The case of even D, which includes a conformal stress‐energy tensor with a rational 3‐point function, is of particular interest. Recent progress, reviewed in the talk, includes a full account of Wightman positivity at the 4‐point level for D=4, and a study of modular properties of thermal expectation values of the conformal energy operator.