bluuebunny/crossref_metadata_2025_split huggingface dataset:
HydrophobicN‐Diazeniumdiolates and the Aqueous Interface of Sodium Dodecyl Sulfate (SDS) Micelles
Authors: Mohr Andreas , Pozo Vila Tommy , Korth Hans‐Gert , Rehage Heinz , Sustmann Reiner 
Published: October 2008

AbstractZwitterionic diazeniumdiolates of the form RN[N(O)NO−](CH2)2NH2+R, where R=CH3(1), (CH2)3CH3(2), (CH2)5CH3(3), and (CH2)7CH3(4) were synthesized by reaction of the corresponding diamines with nitric oxide. Spectrophotometrically determined pKa(O) values, attributed to protonation at the terminal oxygen of the diazeniumdiolate group, show shifts to higher values in dependence of the chain lengths of R. The pH dependence of the decomposition of NO donors1–3was studied in buffered solution between pH 5 and 8 at 22 °C, from which pKa(N) values for protonation at the amino nitrogen, leading to release of NO, were estimated. It is shown that the decomposition of these diazeniumdiolates is markedly catalyzed by anionic SDS micelles. First‐order rate constants for the decay of1–4were determined in phosphate buffer pH 7.4 at 22 °C as a function of SDS concentration. Micellar binding constants,KSM, for the association of diazeniumdiolates1–3with the SDS micelles were also determined, again showing a significant increase with increasing length of the alkyl side chains. The decomposition of1–3in micellar solution is quantitatively described by using the pseudo‐phase ion‐exchange (PIE) model, in which the degree of micellar catalysis is taken into account through the ratio of the second‐order rate constants (k2m/k2w) for decay in the micelles and in the bulk aqueous phase. The decay kinetics of1–3were further studied in the presence of cosolvents and nonionic surfactants, but no effect on the rate of NO release was observed. The kinetic data are discussed in terms of association to the micelle–aqueous phase interface of the negatively charged micelles. The apparent interfacial pH value of SDS micelles was evaluated from comparison of the pH dependence of the first‐order decay rate constants of2and3in neat buffer and the rate data obtained for the surfactant‐mediated decay. For a bulk phase of pH 7.4, an interfacial pH of 5.7–5.8 was determined, consistent with the distribution of H+in the vicinity of the negatively charged micelles. The data demonstrate the utility of2and3as probes for the determination of the apparent pH value in the Stern region of anionic micelles.
Hydration Dynamics of Water near an Amphiphilic Model Peptide at Low Hydration Levels: A Dielectric Relaxation Study
Authors: Sasisanker Padmanabhan , Weingärtner Hermann 
Published: October 2008

AbstractA dielectric relaxation study of aqueous solutions of the amphiphilic model peptide N‐acetyl‐leucine amide (NALA) at 298 K over a wide range of hydration levels is presented. The experiments range from states where water builds up several hydration layers to states where single water molecules or small water clusters are shared by several NALA molecules. The dielectric spectra reveal two modes on the 10 and 100 ps timescales. These are largely broadened with regard to the Lorentzian shape caused by simple Debye‐type relaxation, and are well described by the Kohlrausch–Williams–Watts stretched exponential function. The fast mode is assigned to water reorientation comprising bulk water as well as hydration water. Even when all water molecules are in contact with the solute, this fast component is dominant, and its mean relaxation time is retarded by less than a factor of two relative to neat water. The amplitude of the slow process is far higher than expected for the dipolar reorientation of the solute. The observations are consistent with results from molecular dynamics simulations for a similar model peptide reported in the literature. They suggest that the slow relaxation mode is mainly founded in peptide–water dipolar couplings, with some additional contribution from slowly reorienting hydration water molecules. The results are discussed with regard to the hydration dynamics of proteins and the interpretation of dielectric spectra of protein solutions.
Rh‐Catalyzed Asymmetric Hydrogenation of Unsaturated Lactate Precursors in Propylene Carbonate
Authors: Schäffner Benjamin , Andrushko Vasyl , Holz Jens , Verevkin Sergey P. , Börner Armin 
Published: October 2008

AbstractThe asymmetric hydrogenation of α‐acetoxy acrylates to O‐acetyl lactates with Rh catalysts based on chiral bisphospholane ligands was investigated in propylene carbonate (PC) as “green” solvent. In contrast to DuPHOS‐type ligands, catASium M ligands lead to full conversion of the substrate in PC and induce excellent enantioselectivities for ethyl ester and methyl ester substrates (>98 %). Moreover, the undesired opening of the maleic anhydride moiety of the catASium M ligand observed in MeOH can be prevented under these conditions. The chiral product can be easily separated from the carbonate solvent by distillation. In this way, an ecologically benign process for the production of enantiopure lactic acid derivatives was established which offers a highly efficient catalytic transformation in a green solvent under mild conditions (1–10 bar H2).
Comparison of conventional Papanicolaou smears and fluid‐based, thin‐layer cytology with colposcopic biopsy control in central Italy: A consecutive sampling study of 461 cases
Authors: Rahimi Siavash , Carnovale‐Scalzo Caterina , Marani Carla , Renzi Cristina , Malvasi Antonio , Votano Sergio 
Published: October 2008

AbstractThe aim of this study was to compare the cytologic diagnosis and specimen adequacy of conventional Papanicolaou (CP) and fluid‐based, thin‐layer [ThinPrep (TP), Cytyc, Boxborough, MA] cervical cytology in a population from central Italy. CP and TP samples were collected simultaneously using a consecutive sampling method on women presenting for cervical screening. Colposcopy was performed as clinically indicated, and biopsy results were compared with cytologic diagnoses. Among the 461 patients included in the study, 413 were negative at both CP and TP, 9 had unsatisfactory results at both tests and 39 patients presented abnormal results at CP, TP or both. Cohen's Kappa was 0.77 showing good agreement between CP and TP test results. Histological data were available for 20 (51.28%) of the 39 patients with at least one positive test. Among the 13 patients with HSIL at histology, 7 had HSIL at CP (sensitivity 53.85%) and 5 at TP (sensitivity 38.46%). For all three patients with squamous cell carcinoma (SCC) at histology, CP and TP had shown the same diagnosis (sensitivity 100%). The positive predictive values were 33.33% for CP and 25.0% for TP regarding the LSIL diagnosis and 100% for both CP and TP regarding HSIL and SCC diagnoses. Our results may be influenced by the consecutive sampling procedure. Diagn. Cytopathol. 2009. © 2008 Wiley‐Liss, Inc.
The Role of Axial Ligation in Nitrate Reductase: A Model Study by DFT Calculations on the Mechanism of Nitrate Reduction
Authors: Pal Kuntal , Sarkar Sabyasachi 
Published: October 2008

AbstractThe reactivity differences of the model anionic complexes [Mo(mnt)2(X)(PPh3)]– [mnt2– = 1,2‐dicyanoethylenedithiolate; X = SPh (1a), SEt (1b), Cl (1c), Br (1b)] towards oxygen atom transfer from nitrate, which is a key step performed by nitrate reductase, has been investigated by density functional theory calculations. Unlike complexes 1a and 1b, complexes 1c and 1d do not react with nitrate. Thermodynamically, all these complexes have a similar ability to generate the pentacoordinate active state [Mo(mnt)2(X)]– by dissociation of PPh3, although the inaccessibility of the dxy orbital in 1c,d and the instability of the corresponding nitrate‐bound enzyme substrate (ES) type complex contributes to their failure to reduce nitrate. The nature of the ES complex for 1a,b is described. The variation in the experimental data due to the change of axial ligation from SPh to SEt on the catalytic pathway has also been addressed. The gas‐phase and solvent‐corrected potential energy surface for the reaction of 1a,b with nitrate are established with fully optimized minima and transition states.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Transition Metal Complexes of N‐Heterocyclic Germylenes
Authors: Ullah Farman , Kühl Olaf , Bajor Gabor , Veszprémi Tamas , Jones Peter G. , Heinicke Joachim 
Published: October 2008

AbstractThe five‐membered N‐heterocyclic germylenes (NHGe) 1a–3a, with or without benzo or naphtho anellation, react with [Mo(CO)3(cht)] (cht = 1,3,5‐cycloheptatriene) to form thefac‐[(NHGe)3Mo(CO)3] complexes 1b–3b. Similarly, [Ni(bnNHGe)4] was obtained from the benzo‐anellated germylene (bnNHGe) and Ni(1,5‐cod)2; attempts to synthesize less electron‐rich complexes with mono‐ or divalent transition metals failed. The CO valence vibrations in the IR spectra of 1b–3b, together with their short GeII–Mo bonds (as determined by X‐ray crystallography), hint at the weak donor and good π‐acceptor properties of the ligands. Quantum chemical studies on the benzo‐anellated germylene, which are supported by the good correlation between calculated and experimental (PES) orbital ionization potentials, confirm this proposal in terms of the low energy of the Ge lone electron pair and two higher π‐MOs. The slight folding about the C–C bridging and N···N axes observed for the benzo‐anellated (NHGe)molybdenum and ‐nickel complexes by X‐ray structure analyses, may be due to packing effects. Quantum chemical calculations on slightly bent (for dineopentyl substitution in the gas phase) and planar bnNHGe complexes show that the energy differences between the two are very small.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
An integrated threat model of explicit and implicit attitudes
Authors: Aberson Christopher L. , Gaffney Amber M. 
Published: October 2008

AbstractThe current study applied integrated threat theory (ITT) to the prediction of implicit and explicit attitudes toward African‐Americans. We tested models predicting attitudes from threats (intergroup anxiety, realistic, and symbolic) and antecedents to threat (contact, status, ingroup identification, and negative stereotyping). Data collected from 389 White undergraduate participants indicated that ITT is a good model for predicting both implicit and explicit attitudes. With few exceptions, antecedents predicted threats, and threats mediated the impact of antecedents on attitudes. This work adds importantly to ITT as it demonstrated common predictors of explicit and implicit attitudes, distinguished between negative and positive forms of contact, and tested a latent variable model. We discuss theoretical implications for dual process interpretations of implicit and explicit attitudes. Copyright © 2008 John Wiley & Sons, Ltd.
A Novel Sensor Based on Layer‐by‐Layer Hybridized Phosphomolybdate and Poly(ferrocenylsilane) on a Cysteamine Modified Gold Electrode
Authors: Chen Chuangye , Song Yonghai , Wang Li 
Published: October 2008

AbstractA novel sensor have been constructed by layer‐by‐layer hybridizing phosphomolybdate (POM) and poly(ferrocenylsilane) (PFS) on a cysteamine modified gold electrode. The properties and performance of the sensor have been measured by electrochemistry and atomic force microscopy in detail. The results showed that the constructed multilayers modified gold electrode combined the properties of POM and PFS, and exhibited good electrocatalytic ability to a series of inorganic ions, including BrO$\rm{ {_{3}^{-}}}$, IO$\rm{ {_{3}^{-}}}$, NO$\rm{ {_{2}^{-}}}$, Fe3+, ascorbic acid and SO$\rm{ {_{3}^{2-}}}$. The well catalytic activity of the sensor was ascribed to the porous structure of hybrid POM‐PFS multilayer. The resulted sensor exhibited extremely fast amperometric response, low detection limit, high selectivity and wide linear range to these analyses.
Electrochemical Biosensing of DNA Immobilized Poly(Vinylferrocenium) Modified Electrode
Authors: Kuralay Filiz , Erdem Arzum , Abacı Serdar , Özyörük Haluk , Yıldız Attila 
Published: October 2008

AbstractThe polymer, poly(vinylferrocenium) (PVF+) modified electrode was developed as the first time herein for the improved electrochemical sensing of DNA based on the oxidation signals of polymer and guanine. The morphologies of polymer film and DNA immobilized polymer film were examined using scanning electron microscope (SEM). The electrochemical behavior of polymer modified electrode was investigated by using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in the absence/presence of DNA. Experimental parameters, such as the polymeric film thickness, the DNA immobilization time, the concentration of buffer solution, pH and DNA concentration were examined in order to obtain more sensitive and selective electrochemical signals. After optimization studies, DNA hybridization was also investigated.
Designing unique words for near‐optimal training in block transmission systems
Authors: Coon Justin P. , Sandell Magnus 
Published: October 2008

AbstractIn this paper, we consider the problem of designing unique words (UWs) in single‐carrier block transmission systems for the purpose of performing bandwidth efficient channel estimation. By first deriving the Cramér‐Rao lower bound (CRLB) for the UW‐based channel estimator, we show that designing optimal UWs reduces to a problem of constructing sequences of lengthQ ≤ N/2that, when padded with zeros to make a length‐Nsequence, have good periodic autocorrelation properties. We then show that the only class of short (length‐Q) sequences that, when padded withN − Qzeros, have perfect periodic autocorrelation properties is the class of Kronecker delta sequences. Due to the fact that these sequences typically suffer from a high peak‐to‐average power ratio (PAPR), we then formulate two optimisation procedures to find near‐optimal UWs under certain constraints. Finally, we show that the sequences that are found with the proposed technique perform significantly better than Kronecker delta sequences that have been scaled to meet a given PAPR constraint. Copyright © 2008 John Wiley & Sons, Ltd.
Forecasting using high‐frequency data: a comparison of asymmetric financial duration models
Authors: Zhang Qi , Cai Charlie X , Keasey Kevin 
Published: October 2008

AbstractThe first purpose of this paper is to assess the short‐run forecasting capabilities of two competing financial duration models. The forecast performance of the Autoregressive Conditional Multinomial–Autoregressive Conditional Duration (ACM‐ACD) model is better than the Asymmetric Autoregressive Conditional Duration (AACD) model. However, the ACM‐ACD model is more complex in terms of the computational setting and is more sensitive to starting values. The second purpose is to examine the effects of market microstructure on the forecasting performance of the two models. The results indicate that the forecast performance of the models generally decreases as the liquidity of the stock increases, with the exception of the most liquid stocks. Furthermore, a simple filter of the raw data improves the performance of both models. Finally, the results suggest that both models capture the characteristics of the micro data very well with a minimum sample length of 20 days. Copyright © 2008 John Wiley & Sons, Ltd.
Inhibition of Kupffer cell-mediated early proinflammatory response with carbon monoxide in transplant-induced hepatic ischemia/reperfusion injury in rats
Authors: Tomiyama Koji , Ikeda Atsushi , Ueki Shinya , Nakao Atsunori , Stolz Donna B. , Koike Yasushi , Afrazi Amin , Gandhi Chandrashekhar , Tokita Daisuke , Geller David A. , Murase Noriko 
Published: October 2008

Abstract

Proinflammatory responses play critical roles in hepatic ischemia/reperfusion (I/R) injury associating with liver transplantation (LTx), and carbon monoxide (CO) can effectively down-regulate them. Using wild-type (WT) to enhanced green fluorescent protein (EGFP)-transgenic rat LTx with 18-hour cold preservation in University of Wisconsin solution, this study analyzed the relative contribution of donor and host cells during early posttransplantation period and elucidated the mechanism of hepatic protection by CO. CO inhibited hepatic I/R injury and reduced peak alanine aminotransferase levels at 24 hours and hepatic necrosis at 48 hours. Abundant EGFP+ host cells were found in untreated WT liver grafts at 1 hour and included nucleated CD45+ leukocytes (myeloid, T, B, and natural killer cells) and EGFP+ platelet-like depositions in the sinusoids. However, reverse transcription polymerase chain reaction (RT-PCR) analysis of isolated graft nonparenchymal cells (NPCs) revealed that I/R injury-induced proinflammatory mediators [for example, tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and inducible nitric oxide synthase (iNOS)] were not up-regulated in purified CD45+ cells of donor or host origin. Instead, TNF-α and IL-6 messenger RNA (mRNA) elevation was exclusively seen in isolated CD68+ cells, whereas iNOS mRNA up-regulation was seen in hepatocytes. Nearly all CD68+ cells at 1 hour after LTx were EGFP− donor Kupffer cells, and CO efficiently inhibited TNF-α and IL-6 up-regulation in the CD68+ Kupffer cell fraction. When graft Kupffer cells were inactivated with gadolinium chloride, activation of inflammatory mediators in liver grafts was significantly inhibited. Furthermore,

in vitro

rat primary Kupffer cell culture also showed significant down-regulation of lipopolysaccharide (LPS)-induced inflammatory responses by CO.

Conclusion:

These results indicate that CO ameliorates hepatic I/R injury by down-regulating graft Kupffer cells in early postreperfusion period. The study also suggests that different cell populations play diverse roles by up-regulating distinctive sets of mediators in the acute phase of hepatic I/R injury. (Hepatology 2008;48:1608–1620.)
A dual role of p21 in liver regeneration and hepatocarcinogenesis
Authors: Liedtke Christian , Trautwein Christian 
Published: October 2008

Willenbring H, Sharma AD, Vogel A, Lee AY, Rothfuss A, Wang Z, Finegold M, Grompe M. Loss of p21 permits carcinogenesis from chronically damaged liver and kidney epithelial cells despite unchecked apoptosis. Cancer Cell 2008;14:59-67 (Reprinted with permission).

Abstract
Accumulation of toxic metabolites in hereditary tyrosinemia type I (HT1) patients leads to chronic DNA damage and the highest risk for hepatocellular carcinomas (HCCs) of any human disease. Here we show that hepatocytes of HT1 mice exhibit a profound cell-cycle arrest that, despite concomitant apoptosis resistance, causes mortality from impaired liver regeneration. However, additional loss of p21 in HT1 mice restores the proliferative capabilities of hepatocytes and renal proximal tubular cells. This growth response compensates cell loss due to uninhibited apoptosis and enables animal survival but rapidly leads to HCCs, renal cysts, and renal carcinomas. Thus, p21's antiproliferative function is indispensable for the suppression of carcinogenesis from chronically injured liver and renal epithelial cells and cannot be compensated by apoptosis.
Reshaping AAV vectors for liver gene therapy
Authors: Kühnel Florian , Kubicka Stefan 
Published: October 2008

Grimm D, Lee JS, Wang L, Desai T, Akache B, Storm TA, Kay MA. In vitro and in vivo gene therapy vector evolution via multispecies interbreeding and retargeting of adeno-associated viruses. J Virol 2008;82:5887-5911. (Reprinted with permission.)

Abstract
Adeno-associated virus (AAV) serotypes differ broadly in transduction efficacies and tissue tropisms and thus hold enormous potential as vectors for human gene therapy. In reality, however, their use in patients is restricted by prevalent anti-AAV immunity or by their inadequate performance in specific targets, exemplified by the AAV type 2 (AAV-2) prototype in the liver. Here, we attempted to merge desirable qualities of multiple natural AAV isolates by an adapted DNA family shuffling technology to create a complex library of hybrid capsids from eight different wild-type viruses. Selection on primary or transformed human hepatocytes yielded pools of hybrids from five of the starting serotypes: 2, 4, 5, 8, and 9. More stringent selection with pooled human antisera (intravenous immunoglobulin [IVIG]) then led to the selection of a single type 2/type 8/type 9 chimera, AAV-DJ, distinguished from its closest natural relative (AAV-2) by 60 capsid amino acids. Recombinant AAV-DJ vectors outperformed eight standard AAV serotypes in culture and greatly surpassed AAV-2 in livers of naïve and IVIG-immunized mice. A heparin binding domain in AAV-DJ was found to limit biodistribution to the liver (and a few other tissues) and to affect vector dose response and antibody neutralization. Moreover, we report the first successful in vivo biopanning of AAV capsids by using a new AAV-DJ–derived viral peptide display library. Two peptides enriched after serial passaging in mouse lungs mediated the retargeting of AAV-DJ vectors to distinct alveolar cells. Our study validates DNA family shuffling and viral peptide display as two powerful and compatible approaches to the molecular evolution of novel AAV vectors for human gene therapy applications.
Synthesis and Reactivity in [3+2] Cycloadditions of Isoxanthopterin N(5)‐Oxides – A New Synthesis of 6‐Substituted Pteridinediones
Authors: Steinlin Thomas , Sonati Tiziana , Vasella Andrea 
Published: October 2008

AbstractIntramolecular condensation of the N‐(4‐amino‐5‐nitrosopyrimidin‐4‐yl)‐2‐chloroacetamide 2 led to the pteridinone N(5)‐oxide 4, while treatment of 2 with Me3P yielded the 8‐(chloromethyl)purine 3. A high‐yielding [3+2] dipolar cycloaddition of the N(5)‐oxide 4 to electron‐poor dipolarophiles, followed by spontaneous N,O‐bond cleavage, gave the C(6)‐substituted pteridinones 8a–8d that were deprotected to provide the pteridine‐4,7(3H,8H)‐diones 9a–9d, constituting a new synthesis of pterinones possessing a functionalised side chain at C(6).
Is it HIV TTP or HIV‐associated thrombotic microangiopathy?
Authors: Brecher Mark E. , Hay Shauna N. , Park Yara A. 
Published: October 2008

AbstractThrombocytopenia is a common complication of Human Immunodeficiency Virus (HIV) infection. With advanced HIV disease, the presence of both thrombocytopenia and schistocytosis are frequently observed. In such cases, the diagnosis of HIV associated TTP is often considered. This article reviews emerging concepts of HIV associated microangiopathies. It concludes that the pathophysiology, in many cases seems to be distinct from idiopathic TTP (particularly with advanced HIV disease—<100 CD4/microliter). A sine que non for successful therapy of HIV‐TMA appears to be the treatment of the underlying HIV infection.infection. J. Clin. Apheresis, 2008. © 2008 Wiley‐Liss, Inc.
Transport infrastructure and foreign direct investment
Authors: Khadaroo A. J. , Seetanah B. 
Published: October 2008

AbstractThis paper analyses the role of infrastructure availability, particularly with respect to transportation, in improving the investment climate for and in determining the attractiveness of foreign direct investment (FDI) inflows. The study is initially based on the small island developing state of Mauritius for the period 1960–2004. Using an ARDL approach, transport infrastructure availability is seen to have contributed to the relative attractiveness of the country towards FDI and such is also the case for non‐transport infrastructure. Moreover, the presence of dynamism and endogeneity is also established in FDI modelling. The analysis was then extended for the case of a sample of 20 African economies over the period 1986–2000. Using panel data framework, the fixed effect model estimated a positive and significant coefficient for transport infrastructure, implying that foreign direct investors are sensitive to transport capital. The other type of infrastructure is also judged to be important by these investors, though to a slightly lesser extent than transport. These findings supplement the existing literature on the determinant of FDI. Copyright © 2008 John Wiley & Sons, Ltd.