bluuebunny/crossref_metadata_2025 huggingface dataset:
Remote ischaemic preconditioning of the hind limb reduces experimental liver warm ischaemia–reperfusion injury
Authors: Kanoria S , Jalan R , Davies N A , Seifalian A M , Williams R , Davidson B R
Published: April 2006

Background

Direct ischaemic preconditioning of the liver reduces ischaemia–reperfusion injury (IRI). Remote ischaemic preconditioning (RIPC) of a limb has been shown to reduce IRI to the heart. This study determined the effect of brief remote ischaemia to the limb in reducing early liver warm IRI.

Methods

Twenty-eight male rabbits were allocated to four groups: sham operated, RIPC alone, IRI alone, and RIPC plus IRI. RIPC was induced in the leg with a tourniquet, before liver IRI, by three alternate cycles of 10 min ischaemia followed by 10 min reperfusion. Liver IRI was produced by total inflow occlusion for 25 min. Markers of liver injury and systemic and hepatic haemodynamics were measured for 2 h after reperfusion.

Results

At 2 h, IRI alone was associated with increased serum levels of aminotransferases, and reduced mean arterial blood pressure, hepatic blood flow and peripheral oxygen saturation. There was significant improvement in these variables in animals that had RIPC before liver IRI, and hepatic venous nitrate/nitrite levels were also significantly higher.

Conclusion

In this experimental model RIPC appeared to reduce liver IRI.
A Series of Unconjugated Ferrocenyl Phenols: Prospects as Anticancer Agents
Authors: Hillard Elizabeth , Vessières Anne , Le Bideau Franck , Plażuk Damian , Spera Daniela , Huché Michel , Jaouen Gérard
Published: April 2006

We recently reported that a ferrocenyl diphenol butene derivative showed a very strong cytotoxic effect on both hormone‐dependent and ‐independent breast cancer cell lines. In order to obtain more information about the structure–activity relationship in the cytotoxicity of small ferrocene compounds, we have prepared a series of simple unconjugated ferrocenyl diphenol complexes (ortho,para; meta,para; para,para). These compounds retain a reasonable to good affinity for both estrogen receptor types, with higher values for the β form, and superior binding for the para,para diphenol complex (RBA=28 %). In vitro these complexes exhibit significant cytotoxic effects on hormone‐independent prostate (PC3) and breast cancer cell lines (MDA‐MB231), with IC50 values between 2.5 and 4.1 μM. This effect is more marked with PC3, the ortho,para diphenol complex proving the most effective. On the hormone‐dependent MCF7 breast cancer cell line, the observed effect seems to be the result of two components, one cytotoxic (antiproliferative), the other estrogenic (proliferative). Electrochemical studies show that the cytotoxic effect of the complexes correlates with the ease of oxidation of the ferrocene group. All these complexes are much less cytotoxic than the ferrocenyl diphenol butene derivative.
CMS proposed revisions to conditions to participation: Part II—patient care
Authors: Levy Ralph
Published: April 2006

In February 2005 the Centers for Medicare and Medicaid Services (CMS) released proposed conditions of coverage that must be met by all dialysis facilities in order to be reimbursed by the CMS for services provided to federally insured patients. If adopted, these proposed regulations would replace entirely the conditions of coverage as promulgated by CMS in 1976. Part I of this article, which appeared in the March issue of D&T, discussed the (less controversial) patient safety provisions of these proposed regulations. This, the second installment of this three‐part discussion, addresses the far‐reaching provisions of the proposed conditions relative to patient care. Next month, the final installment of this series will address the administrative provisions of the proposed regulations.
Anemia following renal transplantation: Find it and treat it
Authors: Bihl Geoffrey R.
Published: April 2006

Question: A 34‐year‐old female patient received a cadaveric kidney transplant 22 months ago, and her serum creatinine is 2.2 dL. Despite an extensive workup for persistent anemia, her hemoglobin remains below 9 g/dL. Where to now? This article investigates the reasons anemia post‐transplant occurs, and explores its consequences and treatment options.
Effect of mutual coupling and manufacturing error of array for DOA estimation of ESPRIT algorithm
Authors: Inoue Yuki , Arai Hiroyuki
Published: April 2006

With direction‐of‐arrival estimation by the ESPRIT method, this paper investigates the effect of short spacing between the transmitter and receiver and of mutual coupling and array manufacturing error on the estimation error. A simulation model is presented. The effect of these errors on direction‐of‐arrival estimation is quantitatively presented. It is shown that the maximum estimation error is inversely proportional to the distance between the transmitter and receiver and that the ranges and the standard deviation of the estimation errors can be reduced in the range of 0° <θ1 <60° if the manufacturing error is reduced. Further, the validity of the simulation is confirmed by experiments in an anechoic chamber. It is also confirmed that mutual coupling and manufacturing error in the array antenna are the main causes of the estimation error in the direction‐of‐arrival estimation experiment. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 89(9): 68–76, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10230
Achieving per‐flow fairness in wireless ad hoc networks
Authors: Shagdar Oyunchimeg , Nakagawa Kenji , Zhang Bing
Published: April 2006

Mobile ad hoc networks attract tremendous attention as one form of future network configuration. Among wireless LAN technologies, the IEEE 802.11MAC standard can be considered as the most prominent technology deployed in ad hoc networks. For realization of mobile ad hoc networks, providing QoS support in ad hoc networks is an important task. Among numerous parameters of QoS, per‐flow fairness is an important and problematic issue in ad hoc networks. In the traditional wireline networks, per‐flow unfairness occurs mainly due to the link layer. However, in mobile ad hoc networks, in addition to the link layer, the MAC layer has significant impact on per‐flow fairness problems. In particular, although IEEE 802.11MAC provides per‐node fair bandwidth allocation, in order to achieve per‐flow fairness, a method that provides per‐flow fair bandwidth allocation is required. In this paper, a new scheme is proposed that enables a fair bandwidth allocation to each flow. In addition to fairness, the proposed scheme provides a positive impact on the network in terms of total performance and medium utility. The performance of the proposed scheme is investigated with an ns‐2 network simulator. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 89(8): 37–49, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20250
Estimation of position and radius of cylindrical targets using MUSIC algorithm in cross‐borehole radar
Authors: Miwa Takashi , Arai Ikuo
Published: April 2006

To date, for the tomographic signals obtained in cross‐borehole radar measurement in which transmitting and receiving antennas are scanned independently, a position estimation method for the isolated reflector has been studied by applying the transmission and reception array MUSIC method. However, when the operating wavelength and the size of the conducting cylinder cannot be neglected, as in the case of buried pipes, there is an error in the estimated position in the conventional method when the scattered wave from the point scatterer is used as the steering vector for position estimation. In this paper, the steering vector obtained from rigorous solution of scattering from a conducting cylinder is used. It is shown that the position estimation accuracy is improved by taking into account the effect of the elimination of the direct wave. It is also shown that the cylinder position and the radius can be estimated simultaneously by using the cylindrical radius as an estimation parameter. The effectiveness of multifrequency synthesis is discussed. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 89(8): 26–36, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20271
Improvement of transmission properties of synchronized QoS ad hoc network by rapid control method
Authors: Sugiyama Hisayoshi , Tsujioka Tetsuo , Murata Masashi
Published: April 2006

A rapid control method is proposed to improve the transmission properties of a synchronized QoS ad hoc network (synchronized QoS network). The synchronized QoS network has already been proposed to assure transmission bandwidth in ad hoc networks. However, the VC (virtual circuit) establish time and the VC breakage interval both expand in this network. Furthermore, the rate of successful communication deteriorates in relation to network topology changes. These problems become serious when a synchronized QoS network is applied to the multirobot rescue systems operating in urban disaster areas. The rapid control method modifies the frame structure of the conventional synchronized QoS network. This method accelerates control packet transmission and therefore improves the VC establish time, VC breakage interval, and the rate of successful communications. These improvements are confirmed by computer simulations in which a reconnaissance into distant space by a multirobot rescue system is simulated. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 89(9): 51–59, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20278
Derivation of scattering parameter using local scattering modeling and its application to antenna beam selection
Authors: Tsuji Hiroyuki , Yamada Kenichi
Published: April 2006

We propose a method of beam selection to improve the quality of signals in multipath environments, in which multiple signals impinge on an array antenna from several directions, which uses a new parameter based on local scattering modeling. This “scattering parameter” relates to the degradation of signals impinging on an array antenna and can be used to select the direction‐of‐arrival of the signal for use in forming the antenna beam. We determine the relationship between the scattering parameter and the Rice factor and propose a method of estimating the parameter. The scattering parameter enables us to select the antenna beam without calculating the bit error rate of each arriving signal. Numerical and experimental results show that our method is effective. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 89(9): 41–50, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20279
A proposal and evaluations of marking scheme in DiffServ
Authors: Suematsu Toshimichi , Takenaka Toyofumi
Published: April 2006

Recently, the requirements for real‐time applications have increased and the need for QoS guarantees on the Internet has been intensified. In response to such requirements, the IETF has proposed the IntServ and DiffServ architectures with QoS guarantee. DiffServ is an architecture consisting of a core and edge. In the core, scalability is assured by QoS guarantee using AQM without taking account of the flow. However, it has been pointed out that there are problems at the time of mixture of TCP and UDP flows and in the fairness between edge flows. In order to resolve these problems, this paper proposes three‐color marker control with TSW based on the following policy: (a) guarantee of transmission flow according to the SLA and (b) packet discarding based on the degree of violation for transmission flows violating the SLA. The proposed system is evaluated by simulation and its effectiveness is confirmed. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 89(9): 32–40, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20286
Radiation properties of modified fractal microstrip antennas
Authors: Tada Shinya , Chayono Ridho , Shinohe Yusuke , Kimura Yuichi , Haneishi Misao
Published: April 2006

This paper describes the method of configuration and the radiation properties of a new type of multi‐band planar antenna with a radiating element made of a microstrip antenna (MSA) with a slit‐loaded modified Sierpinski Gasket fractal antenna. In order to verify the multiband characteristics of this antenna, triangular MSA elements loaded with slits of a modified Sierpinski Gasket structure are fabricated. According to the experiment, the present test antenna exhibits excellent multiband characteristics in the C‐band and X‐band. Also, the measured values of the return loss and the radiation patterns are in good agreement with the results given by an electromagnetic simulator in the range meaningful for design. Thus, this antenna system is a useful format for a multiband planar antenna. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 89(9): 10–21, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20296
Single‐stranded small interfering RNA are more immunostimulatory than their double‐stranded counterparts: A central role for 2′‐hydroxyl uridines in immune responses
Authors: Sioud Mouldy
Published: April 2006

It has recently become apparent that certain small interfering RNA (siRNA) sequences stimulate the innate immunity through endosomal Toll‐like receptors (TLR), particularly TLR7 and TLR8. However, it remains unclear whether siRNA duplexes act as specific ligands for these receptors. To address this question and to overcome the problem of immune activation by siRNA, several RNA sequences were chemically synthesized and their effects were investigated. Results indicate that human peripheral blood mononuclear cells (PBMC) recognize and respond to a large number of sense or antisense single‐stranded (ss) siRNA. In most cases immunostimulatory RNA motifs are more effectively recognized by innate immunity in the context of ss siRNA as compared to siRNA duplexes. Novel immunostimulatory RNA motifs were identified and their replacement with adenosines abrogated immune activation. Most notably, replacement of the 2′‐hydroxyl uridines with either 2′‐fluoro, 2′‐deoxy or 2′‐O‐methyl uridines abrogated immune activation. Thus, immune recognition of RNA by TLR can be evaded by 2′‐ribose modifications of only uridines. Collectively, the data should facilitate the development of siRNA therapeutics and expand the understanding of how RNA is sensed by innate immunity.
Tris(tropolonato)phenanthroline Lanthanide(III) Complexes as Photochemical Devices
Authors: Bertolo Laura , Tamburini Sergio , Vigato Pietro Alessandro , Porzio William , Macchi Giorgio , Meinardi Francesco
Published: April 2006

The tris‐tropolonato erbium(III) complexes [Er(hino)3(phen)] and [{Er(hino)3}2(pdon)] (H‐hino = 2‐hydroxy‐6‐isopropylcyclohepta‐2,4,6‐trien‐1‐one; phen = 1,10‐phenanthroline; pdon = 1,10‐phenanthroline‐5,6‐dione) have been prepared by reaction of [Er(hino)3]n with the appropriate chelating ligand in alcoholic solution. The complexes were characterized by elemental analyses, TG, ESI MS, 1H NMR, and IR spectroscopy, also by comparison with the properties of the analogous EuIII and YbIII complexes. The ESI‐MS spectroscopy of the complex with the ditopic ligand pdon parallels the other physico‐chemical data (IR, NMR), confirming the occurrence of a dinuclear entity. All the investigated ErIII complexes show efficient NIR emissions at about 1550 nm upon excitation at 355 nm in the UV ligand absorption band, emerging as possible candidate as active material for the realization of plastic amplifiers for telecommunications. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Transformation of a Tetranuclear Copper(II) Complex Bridged by Sugar Phosphates into Nucleotide‐Containing Cu4 Aggregations
Authors: Kato Merii , Sah Ajay Kumar , Tanase Tomoaki , Mikuriya Masahiro
Published: April 2006

Reaction of [Cu4(μ‐OH){μ‐(α‐D‐Glc‐1P)}2(L)4(H2O)2]X3 (1a: L = bpy, X = NO3, α‐D‐Glc‐1P = α‐D‐glucopyranose‐1‐phosphate) with Na2[H2ATP] (ATP = adenosine 5′‐triphosphate) readily afforded the ATP‐bridged tetranuclear copper(II) complex [Cu4(μ‐ATP)2(bpy)4] (3), which was characterized by X‐ray crystallographic analysis to consist of four linearly dispersed {CuII(bpy)}2+ fragments bridged by two triphosphate groups of the ATP tetravalent anions. The sugar and adenine base parts of the ATP moieties are away from the copper(II) centers, but the structure was stabilized by weak intramolecular π–π stacking between the ATP purine ring and two bpy ligands and intermolecular hydrogen bonding between the adenine base pairs. The variable‐temperature magnetic susceptibility of complex 3 exhibited only weak antiferromagnetic couplings between the four linearly dispersed CuII ions. A similar reaction of 1a or 2 (L = phen, X = NO3) with Na2[IMP] (IMP = inosine 5′‐monophosphate) yielded a different type of tetracopper(II) complex formulated as [Cu4{μ‐(IMP‐H)}2(L)4(H2O)4](NO3)2 [L = bpy (5), phen (6)], in which the IMP moieties are deprotonated at the N‐1 position of the nucleobase, forming IMP‐H trianions, and four {Cu(bpy)(H2O)}2+ fragments are connected through the N‐1, N‐7, and O‐6 atoms of the nucleobase and the monodentate 5′‐phosphate group. Reaction of 1b (L = bpy, X = Cl) with Na2[UMP] (UMP = uridine 5′‐monophosphate) resulted in a polymeric compound formulated as {[Cu{μ‐(UMP‐H)}(bpy)(H2O)]2[Cu4(μ‐OH){μ‐(α‐d‐Glc‐1P)}2(bpy)4(H2O)2]Cl}n (7). The N‐3 deprotonated [UMP‐H]3– anions connect {Cu(bpy)(H2O)}2+ fragments through the N‐3 nitrogen atom and the phosphate oxygen atoms to afford C2‐helical coordination polymers and the tetracopper(II) complex cations, [Cu4(μ‐OH){μ‐(α‐d‐Glc‐1P)}2(bpy)4(H2O)2]3+, are incorporated between the polymer chains with a C2‐chiral arrangement of the {Cu4(μ‐OH)(μ‐PO4)2(bpy)4(H2O)2} framework constrained to the Λ‐form through inter‐ and intramolecular stacking interactions between the bpy ligands. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Electroanalytical Determination of Carcinoembryonic Antigen at a Silica Nanoparticles/Titania Sol–Gel Composite Membrane‐Modified Gold Electrode
Authors: Liu Yan , Jiang Hong
Published: April 2006

A highly hydrophilic and nontoxic colloidal silica nanoparticle/titania sol–gel composite membrane was prepared on a gold electrode via a chemical vapor deposition method. With carcinoembryonic antigen (CEA) as a model antigen and encapsulation of carcinoembryonic antibody (anti‐CEA) in the composite architecture, this membrane could be used for reagentless electrochemical immunoassay. The presence of silica nanoparticles provided a congenial microenvironment for adsorbed biomolecules. The formation of immunoconjugate by a simple one‐step immunoreaction between CEA in sample solution and the immobilized anti‐CEA introduced the change in the potential. The modified procedure was further characterized by electrochemical impedance spectroscopy and cyclic voltammetry. Compared to the commonly applied methods, i.e., the TiO2 direct embedding procedure, this strategy could allow for antibodies immobilized with higher loading amount and better retained immunoactivity. The resulting immunosensor exhibited high sensitivity, good precision, acceptable stability, accuracy, reproducibility and wide linear range from 1.5 to 240 ng mL−1 with a detection limit of 0.5 ng mL−1 at 3σ. Analytical results of clinical samples show that the developed immunoassay is comparable with the enzyme‐linked immunosorbent assays (ELISAs) method, implying a promising alternative approach for detecting CEA in the clinical diagnosis. Furthermore, this composite membrane could be used efficiently for the entrapment of other biomarkers and clinical applications.
Capillary electrophoretic investigation of the enantioselective metabolism of propafenone by human cytochrome P‐450 SUPERSOMES: Evidence for atypical kinetics by CYP2D6 and CYP3A4
Authors: Afshar Minoo , Thormann Wolfgang
Published: April 2006

An enantioselective CE method was used to identify the ability of CYP450 enzymes and their stereoselectivity in catalyzing the transformation of propafenone (PPF) to 5‐hydroxy‐propafenone (5OH‐PPF) andN‐despropyl‐propafenone (NOR‐PPF). Usingin vitroincubations with single CYP450 enzymes (SUPERSOMES), 5OH‐PPF is shown to be selectively produced by CYP2D6 andN‐dealkylation is demonstrated to be mediated by CYP2D6, CYP3A4, CYP1A2, and CYP1A1. For the elucidation of kinetic aspects of the metabolism with CYP2D6 and CYP3A4, incubations with individual PPF enantiomers and racemic PPF were investigated. With the exception of the dealkylation in presence ofR‐PPF only, which can be described by the Michaelis–Menten model, all CYP2D6‐induced reactions were found to follow autoactivation kinetics. For CYP3A4, all NOR‐PPF enantiomer formation rates as function of PPF enantiomer concentration were determined to follow substrate inhibition kinetics. The formation of NOR‐PPF by the different enzymes is stereoselective and is reduced significantly when racemic PPF is incubated. Clearance values obtained for CYP3A4 dealkylation are stereoselective whereas those of CYP2D6 hydroxylation are not. This paper reports the first investigation of the PPF hydroxylation and dealkylation kinetics by the CYP2D6 enzyme and represents the first report in which enantioselective CE data provide the completein vitrokinetics of metabolic steps of a drug.
Proteomic analysis of macrophages stimulated by lipopolysaccharide: Lipopolysaccharide inhibits the cleavage of nucleophosmin
Authors: Zhang Xiulian , Kuramitsu Yasuhiro , Fujimoto Masanori , Hayashi Eiko , Yuan Xiaoqin , Nakamura Kazuyuki
Published: April 2006

Lipopolysaccharide (LPS) is a complex glycolipid composed of a hydrophilic polysaccharide and a hydrophobic domain that is responsible for the biological activity of LPS. There are many reports about LPS stimulation, and many activated proteins have been detected after LPS stimulation in various cell types. Furthermore, most of the LPS signaling pathways are clear. However, we were interested in examining the changes of LPS‐induced total cytosolic proteins expression and the LPS signaling pathway by the proteomics technique during LPS‐induced macrophage activation. Our study employed two‐dimensional gel electrophoresis and mass spectrometry to analyze the proteins involved in LPS‐induced activation in RAW 264.7 cells. We found 11 protein spots whose expression was different between untreated cells and LPS‐treated cells. Ten protein spots were identified, seven of which, tubulin beta‐4 chain (49.6 kDa, pI 4.78), nucleophosmin (32.6 kDa, pI 4.62, two spots), 40S ribosomal protein SA (P40) (32.7 kDa, pI 4.74), transforming protein RhoA (21.8 kDa, pI 5.83), nucleolin (76.6 kDa, pI 4.69), and T‐complex protein 1 zeta subunit (58 kDa, pI 6.63) were down‐regulated, and three of which, nucleophosmin (32.6 kDa, pI 4.62, two spots) and proteosome subunit alpha type‐1 (29.5 kDa, pI 6.00), were up‐regulated. The suppression of the proteolytic degradation of nucleophosmin was associated with LPS‐induced RAW 264.7 cell activation. Cleaved caspase‐3 decreased, thus it might be involved in proteolysis of nucleophosmin in LPS‐induced macrophage activation. Our study also demonstrated that there was no change of the expression of nucleophosmin at the mRNA level.
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

The 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

The 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

Angiogenesis 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

A 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

Alendronate (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

Dipeptides (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

The 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

Constant 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

Two 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

Conformational 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

Background

Methylation 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.

Procedure

We 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.

Results

Four 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).

Conclusions

As 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

The 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

The 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

AdS/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

We 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

We 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

We 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

We 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

The 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.
Heterotic vacua from general (non‐) Abelian bundles
Authors: Weigand T.
Published: April 2006

We report on the construction of four‐dimensional string vacua by considering general abelian and non‐abelian bundles on an internal Calabi‐Yau for both heterotic theories. The structure of the resulting gauge sector is extremely rich and gives rise to many new model building possibilities. We analyse the chiral spectrum including the contribution from heterotic five‐branes and provide the general consistency conditions. The one‐loop corrected supersymmetry condition on the bundles is found to be that of π‐stability. As an application we present a supersymmetric Standard‐Model like example for the SO(32) string with U(n) bundles on an elliptically fibered Calabi‐Yau.
Stringy effects for spinning strings and the Bethe ansatz
Authors: Schäfer‐Nameki S. , Zamaklar M.
Published: April 2006

The one‐loop worldsheet corrections to spinning strings in the sl(2) subsector of AdS5 × S5 are compared to the quantum string Bethe ansatz. The evaluation of the energy shift is performed in two regimes: a) in the large 𝒥 limit, using zeta‐function regularization and b) in the limit of large winding number. The first computation agrees with the Bethe ansatz in the first three orders while the second computation leads to a disagreement with the string Bethe ansatz prediction at leading order. Careful analysis of the zeta‐function regularization shows, that in this approach perturbative as well as non‐perturbative terms in the string sums are missed. Hence, this together with the result b), implies that the proposed quantum string Bethe equations do not reproduce all terms in the exact string result.