bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vapor phase radiation chemistry studied by electron spin resonance spectroscopy
Authors: Smith D. R. , Tole J. C. 
Published: May 2006

The techniques and some preliminary results of an indirect method of studying vapor phase radiolysis by electron spin resonance (e.s.r.) spectroscopy are reported. After traversing a beam of 40 keV Ar+ ions, a stream of vapor is condensed on a cold finger at 77 °K. Free radicals which are formed by ion bombardment in the vapor phase become trapped in the solid deposit and are detected by e.s.r. Various vapors such as cyclopentane, cyclohexane, benzene, and ethanol have been bombarded at room temperature. The results correlate with conventional radiation chemical data. For example, benzene forms [Formula: see text] (and probably [Formula: see text]) radicals. These may be the intermediates which lead to polymer formation when benzene vapor is irradiated. The potential value of the experiment to vapor phase radiation chemistry is discussed.
Reaction of active nitrogen with ammonia
Authors: Back R. A. , Salahub D. R. 
Published: May 2006

The reaction of14N-active nitrogen with15N-ammonia produces only N2and H2. The nitrogen is exclusively14N15N. It is concluded that the primary process[Formula: see text](where N2* is probably in the A3Σu+state, or a vibrationally excited X1Σg+state) is followed by the secondary reactions[Formula: see text][Formula: see text]which consume nitrogen atoms, in disagreement with earlier conclusions about the ammonia reaction.
Photooxidation of acetone vapor
Authors: Hoare D. E. , Whytock D. A. 
Published: May 2006

The photochemical reaction between acetone and oxygen has been studied at temperatures from 100 to 250 °C at several oxygen pressures with light of 3 130 Å. A study of the quantum yields of all the major products has shown the necessity of introducing the reaction [Formula: see text] [Formula: see text]to the generally accepted mechanism, with a rate constant about 80 times that of the reaction [Formula: see text]at 100 °C. Both this reaction and the reaction of acetyl radicals with oxygen appear to have low or negative activation energies, consistent with a rate-determining process involving combination of the radical with oxygen. The reaction of acetonyl radicals with oxygen to give carbon monoxide is not important at temperatures below 150 °C, but it becomes the most important reaction at temperatures above 250 °C.
An acidity function in ethanol – sulfuric acid based on the protonation of diphenylamines
Authors: Dolman Douglas , Stewart Ross 
Published: May 2006

A Hammett H0 acidity function based on the protonation of 17 diphenylamines in 20 volume % ethanol – aqueous sulfuric acid has been established. The H0 value for the most acidic solution studied (11.2 M sulfuric acid) is −6.97. This acidity function differs from that based on the protonation of azobenzenes in the same solvent system; the latter diverges to more negative H0 values as the sulfuric acid concentration increases.The [Formula: see text] values for the protonation of the diphenylamines vary from +1.36 for 4-methoxy-diphenylamine to − 6.21 for 4,4′-dinitrodiphenylamine. A plot of [Formula: see text] versus the Hammett σ constants for five monosubstituted diphenylamines yields a ρ value of +3.36. The [Formula: see text] values for 4-methoxy-, 4-methyl-, 4-methylsulfonyl-, and 4-nitro-diphenylamine are all less (more negative) than expected from the Hammett substituent constants. The substituent effects on the basicities of aniline and diphenylamine are the same.The basicities of several nitro-substituted diphenylamines appear to vary regularly, and do not reflect the presence of a strong interaction between the nitro group and sulfuric acid.
Thermal decomposition of the ethyl radical
Authors: Loucks L. F. , Laidler K. J. 
Published: May 2006

The kinetics of the thermal decomposition of the ethyl radical to give an ethylene molecule and a hydrogen atom were studied over the pressure range 4 to 650 mm Hg and the temperature range 400 to 500 °C; the mercury-photosensitized decomposition of ethane was used to generate the ethyl radical. The unimolecular decomposition of the ethyl radical was found to be pressure dependent over the entire range of pressures studied, with the order of reaction varying from 1.6 for the lowest pressures to 1.4 at the highest pressures. The extrapolated high-pressure and low-pressure rate constants for the decomposition of the ethyl radical are given by [Formula: see text] [Formula: see text]A best fit of the Kassel equation to the observed pressure dependence shows that s = 8 for this reaction. The results lead to a value of 98 1 kcal/mole for the bond dissociation energy D(C2H5—H). The heat of formation of the ethyl radical was calculated to be 30.0 and 26.2 kcal/mole for 0 °K and 25 °C respectively.
A fixed point theorem for a class of differentiable stable operators in banach spaces
Authors: Azhmyakov Vadim 
Published: May 2006

AbstractWe study Frèchet differentiable stable operators in real Banach spaces. We present the theory of linear and nonlinear stable operators in a systematic way and prove solvability theorems for operator equations with differentiable expanding operators. In addition, some relations to the theory of monotone operators in Hilbert spaces are discussed. Using the obtained solvability results, we formulate the corresponding fixed point theorem for a class of nonlinear expanding operators.
Calcium adsorption and displacement: characterization of lipid monolayers and their interaction with membrane-active peptides/proteins
Authors: Hagge Sven O , Hammer Malte U , Wiese Andre , Seydel Ulrich , Gutsmann Thomas 
Published: May 2006

Abstract

Background
The first target of antimicrobial peptides (AMPs) is the bacterial membrane. In the case of Gram-negative bacteria this is the outer membrane (OM), the lipid composition of which is extremely asymmetric: Whereas the inner leaflet is composed of a phospholipid mixture, the outer leaflet is made up solely from lipopolysaccharides (LPSs). LPS, therefore, represents the first target of AMPs. The binding and intercalation of polycationic AMPs is driven by the number and position of negatively charged groups of the LPS. Also, proteins other than cationic AMPs can interact with LPS, e.g. leading eventually to a neutralization of the endotoxic effects of LPS. We compared different biophysical techniques to gain insight into the properties of the electrical surface potentials of lipid monolayers and aggregates composed of LPSs and various phospholipids and their interaction with peptides and proteins.

Results
The net negative charge calculated from the chemical structure of the phospholipid and LPS molecules is linearly correlated with the adsorption of calcium to two-dimensional lipid monolayers composed of the respective lipids. However, the ζ-potentials determined by the electrophoretic mobility of LPS aggregates can only be interpreted by assuming a dependence of the plane of shear on the number of saccharides and charged groups. Various peptides and proteins were able to displace calcium adsorbed to monolayers.

Conclusion
To characterize the electrical properties of negatively charged phospholipids and LPSs and their electrostatic interaction with various polycationic peptides/proteins, the adsorption of calcium to and displacement from lipid monolayers is a suitable parameter. Using the calcium displacement method, the binding of peptides to monolayers can be determined even if they do not intercalate. The interpretation of ζ-potential data is difficulty for LPS aggregates, because of the complex three-dimensional structure of the LPS molecules. However, the influence of peptides/proteins on the ζ-potential can be used to characterize the underlying interaction mechanisms.
Four genomic islands that mark post-1995 pandemic Vibrio parahaemolyticus isolates
Authors: Hurley Catherine C , Quirke AnneMarie , Reen F Jerry , Boyd E Fidelma 
Published: May 2006

Abstract

Background

Vibrio parahaemolyticus is an aquatic, halophilic, Gram-negative bacterium, first discovered in 1950 in Japan during a food-poisoning outbreak. Infections resulting from consumption of V. parahaemolyticus have increased globally in the last 10 years leading to the bacterium's classification as a newly emerging pathogen. In 1996 the first appearance of a pandemic V. parahaemolyticus clone occurred, a new O3:K6 serotype strain that has now been identified worldwide as a major cause of seafood-borne gastroenteritis.

Results
We examined the sequenced genome of V. parahaemolyticus RIMD2210633, an O3:K6 serotype strain isolated in Japan in 1996, by bioinformatic analyses to uncover genomic islands (GIs) that may play a role in the emergence and pathogenesis of pandemic strains. We identified 7 regions ranging in size from 10 kb to 81 kb that had the characteristics of GIs such as aberrant base composition compared to the core genome, presence of phage-like integrases, flanked by direct repeats and the absence of these regions from closely related species. Molecular analysis of worldwide clinical isolates of V. parahaemolyticus recovered over the last 33 years demonstrated that a 24 kb region named V. parahaemolyticus island-1 (VPaI-1) encompassing ORFs VP0380 to VP0403 is only present in new O3:K6 and related strains recovered after 1995. We investigated the presence of 3 additional regions, VPaI-4 (VP2131 to VP2144), VPaI-5 (VP2900 to VP2910) and VPaI-6 (VPA1254 to VPA1270) by PCR assays and Southern blot analyses among the same set of V. parahaemolyticus isolates. These 3 VPaI regions also gave similar distribution patterns amongst the 41 strains examined.

Conclusion
The 4 VPaI regions examined may represent DNA acquired by the pandemic group of V. parahaemolyticus isolates that increased their fitness either in the aquatic environment or in their ability to infect humans.
How effective is tetracaine 4% gel, before a peripherally inserted central catheter, in reducing procedural pain in infants: a randomized double-blind placebo controlled trial [ISRCTN75884221]
Authors: Lemyre Brigitte , Sherlock Rebecca , Hogan Debora , Gaboury Isabelle , Blanchard Colline , Moher David 
Published: May 2006

AbstractBackgroundProcedural pain relief is sub-optimal in infants, especially small and vulnerable ones. Tetracaine gel 4% (Ametop®, Smith-Nephew) provides pain relief in children and larger infants, but its efficacy in smaller infants and for peripherally inserted central catheters (PICC) remains uncertain. The objective of this trial was to assess the safety and efficacy of tetracaine gel on the pain response of very low birth weight (VLBW) infants during insertion of a PICC.MethodsMedically stable infants greater than or equal to 24 weeks gestation, requiring a non-urgent PICC, were included. Following randomization and double blinding, 1.1 g of tetracaine or placebo was applied to the skin for 30 minutes. The PICC was inserted according to a standard protocol. Pain was assessed using the Premature Infant Pain Profile (PIPP). A 3-point change in the pain score was considered clinically significant, leading to a sample size of 54 infants, with 90% statistical power. Local skin reactions and immediate adverse cardiorespiratory events were noted. The primary outcome, PIPP score at 1 minute, was analysed using an independent Student's t-test.ResultsFifty-four infants were included, 27 +/- 2 weeks gestation, 916 +/- 292 grams and 6.5 +/- 3.2 days of age. Baseline characteristics were similar between groups. The mean PIPP score in the first minute was 10.88 in the treatment group as compared to 11.74 in the placebo group (difference 0.86, 95% CI -1.86, 3.58). Median duration of crying in non-intubated infants was 181 seconds in the tetracaine group compared to 68 seconds in the placebo group (difference -78, 95% CI -539, 117). Local skin erythema was observed transiently in 4 infants (3 in the treatment and 1 in the placebo group). No serious harms were observed.ConclusionTetracaine 4% when applied for 30 minutes was not beneficial in decreasing procedural pain associated with a PICC in very small infants.
Inhibition of homologous recombination repair with Pentoxifylline targets G2 cells generated by radiotherapy and induces major enhancements of the toxicity of cisplatin and melphalan given after irradiation
Authors: Bohm Lothar 
Published: May 2006

AbstractThe presentation reviews the modus operandi of the dose modifying drug Pentoxifylline and the dose enhancement factors which can be achieved in different cell types. Preclinical and clinical data show that Pentoxifylline improves the oxygenation of hypoxic tumours and enhances tumour control by irradiation. In vitro experiments demonstrate that Pentoxifylline also operates when oxygen is not limiting and produces dose modifying factors in the region of 1.2 – 2.0. This oxygen independent effect is poorly understood. In p53 mutant cells irradiation induces a G2 block which is abrogated by Pentoxifylline. The enhancement of cell kill observed when Pentoxifylline and irradiation are given together could arise from rapid entry of damaged tumour cells into mitosis and propagation of DNA lesions as the result of curtailment of repair time. Recovery ratios and repair experiments using CFGE after high dose irradiation demonstrate that Pentoxifylline inhibits repair directly and that curtailment of repair time is not the explanation. Use of the repair defective xrs1 and the parental repair competent CHO-K1 cell line shows that Pentoxifylline inhibits homologous recombination repair which operates predominantly in the G2 phase of the cell cycle. When irradiated cells residing in G2 phase are exposed to very low doses of cisplatin at a toxic dose of 5 %. (TC: 0.05) massive toxicity enhancements up to a factor of 80 are observed in melanoma, squamous carcinoma and prostate tumour cell lines. Enhancements of radiotoxicity seen when Pentoxifylline and radiation are applied together are small and do not exceed a factor of 2.0. The capacity of Pentoxifyline to inhibit homologous recombination repair has not as yet been clinically utilized. A suitable application could be in the treatment of cervical carcinoma where irradiation and cisplatin are standard modality. In vitro data also strongly suggest that regimes where irradiation is used in combination with alkylating drugs may also benefit.
Induction of human neutrophil chemotaxis by Candida albicans-derived β-1,6-long glycoside side-chain-branched β-glucan
Authors: Sato Tadashi , Iwabuchi Kazuhisa , Nagaoka Isao , Adachi Yoshiyuki , Ohno Naohito , Tamura Hiroshi , Seyama Kuniaki , Fukuchi Yoshinosuke , Nakayama Hitoshi , Yoshizaki Fumiko , Takamori Kenji , Ogawa Hideoki 
Published: May 2006

Abstract
Polysaccharide β-1,3-D-glucans (β-glucans) are components of the cell wall of various fungi and show immunomodulatory activities. β-Glucans have been reported to enhance neutrophil accumulation during pathogenic fungi-induced lung inflammation. Therefore, we examined whether β-glucans themselves possess chemotactic activities for human neutrophils. Among several kinds of β-glucans, β-1,6-long glucosyl side-chain-branched β-glucan, isolated from Candida albicans [Candida soluble β-D-glucan (CSBG)], dose-dependently induced neutrophil migration in a Boyden chamber system. In contrast, 1,6-monoglucosyl-branched β-glucans, such as Sparassis crispa-derived β-glucan (SCG) and grifolan (GRN), which were derived from nonpathogenic fungi, hardly induced neutrophil migration. Moreover, CSBG-induced neutrophil migration was inhibited completely by liposomes containing neutral glycosphingolipid lactosylceramide (LacCer; Galβ1-4Glc-ceramide) but not NeuAcα2-3Galβ1-4Glcβ1-1′-Cer ganglioside. Furthermore, binding experiments demonstrated that CSBG bound to glycosphingolipids (such as LacCer) with a terminal galactose residue; however, SCG and GRN (1,6-monoglucosyl-branched β-glucans) did not bind to LacCer. It is important that a Src kinase inhibitor protein phosphatase 1, a phosphatidylinositol-3 kinase (PI-3K) inhibitor wortmannin, and a Gαi/o inhibitor pertussis toxin inhibited neutrophil migration toward CSBG. Taken together, our results suggest that β-1,6-long glucosyl side-chain-branched β-glucan CSBG binds to LacCer and induces neutrophil migration through the activation of Src family kinase/PI-3K/heterotrimeric G-protein signal transduction pathways.
Effects of glucocorticoids on STAT4 activation in human T cells are stimulus-dependent
Authors: Fahey Angela J , Robins R Adrian , Kindle Karin B , Heery David M , Constantinescu Cris S 
Published: May 2006

Abstract
Glucocorticoids affect the immune system by a number of mechanisms, including modulation of cytokine production in lymphocytes. Glucocorticoids suppress T helper cell type 1 immune responses by decreasing the ability of T cells to respond to interleukin (IL)-12, a major inducer of interferon (IFN)-γ. IFN-β increases the expression of the anti-inflammatory cytokine IL-10 and suppresses IL-12. Signaling pathways through IFN-β and the IL-12 receptor (IL-12R) involve activation by phosphorylation of signal transducer and activator of transcription 4 (STAT4). Our aim was to investigate the effects of dexamethasone on STAT4 activation by IFN-β and IL-12 in human T cell blasts. We report that dexamethasone decreases IL-12-induced STAT4 phosphorylation and IFN-γ production and enhances IFN-β-induced STAT4 activation and IL-10 production. These effects are associated with a down-regulation of IL-12Rβ1 expression but an up-regulation of IFN-βR. These results indicate that the effect of glucocorticoids on the STAT4 signaling pathway depends on the stimulus activating that pathway.
Nitric oxide-dependent killing of Cryptococcus neoformans by B-1-derived mononuclear phagocyte
Authors: Ghosn Eliver Eid Bou , Russo Montchilo , Almeida Sandro Rogerio 
Published: May 2006

Abstract
The role of B lymphocytes in protecting the host against pulmonary Cryptococcus neoformans infection is until now, uncertain. A recent study using B lymphocyte-deficient mice suggests that B lymphocytes play a protective role in cryptococcal infection. It has been well established that at least three B cell subsets, B-1a, B-1b, and B-2, are present in the mouse periphery. B-1 cells constitute a minor fraction of the B cell population in the spleen and are not detected in lymph nodes of mice. We demonstrated that B-1 cells migrate to a nonspecific, inflammatory focus and differentiate into macrophage-like cells. However, the role these cells might play on the kinetics and evolution of the inflammatory response and on fungal infection has not yet been established. Based on these data, we decided to investigate the interaction of B-1-derived mononuclear phagocytes (BDMP) with C. neoformans to elucidate the possible influence of this cell in the progression of the disease. In this study, we demonstrated that the BDMP cell internalized C. neoformans and that this process was mediated by complement receptor 3. Thus, our results showed that the BDMP cell was more fungicidal than a macrophage and up-regulated major histocompatibility complex type II and the CD86 costimulatory molecule with the production of proinflammatory cytokines. The phagocytosis of C. neoformans results in the nitric oxide (NO)-mediated death of the fungus, as demonstrated by experiments using NO synthase 2 knockout and aminoguanidine-treated, wild-type mice.
The Relationship between Libido and Testosterone Levels in Aging Men
Authors: Travison Thomas G. , Morley John E. , Araujo Andre B. , O’Donnell Amy B. , McKinlay John B. 
Published: May 2006

Abstract
Context: Although it is known that serum testosterone (T) concentrations are related to libido, the strength of that relationship in community-dwelling men has not yet been determined.
Objective: Our objective was to assess the strength and significance of the association between aging men’s self-reports of libido and serum T concentrations.
Design: Our study was a community-based evaluation of men’s health and aging, including three data collection waves: baseline (T1, 1987–1989) and follow-ups (T2, 1995–1997; T3, 2002–2004). Libido was measured on a 14-point scale assessing self-reported frequency of desire and thoughts/fantasies; low libido was defined as a score of less than 7 of 14.
Setting: We conducted an epidemiological study in greater Boston, Massachusetts.
Participants: There were 1632 men aged 40–70 yr at baseline, with follow-up on 922 (56%) at 9 yr (T2) and 623 (38%) at 15 yr (T3).
Main Outcome Measures: We assessed total and calculated bioavailable T .
Results: Three hundred eighteen (19%) subjects reported low libido at baseline. Libido and T displayed a significant association. However, the difference in mean T levels between those subjects with low libido and those without was small; analyses indicated a 3.4 ng/dl (0.12 nmol/liter) increase in total T per unit increase in libido. Subjects reporting low libido exhibited an increased but modest probability of exhibiting low T. Dividing T concentrations by the number of androgen receptor gene cytosine, adenine, guanine repeats did not enhance associations.
Conclusions: Libido and T concentrations are strongly related at the population level. However, the value of individual patient reports of reduced libido as indicators of low T levels is open to question.
Reduction of Aldehyde with Tributyltin Hydride-HMPA Combined System
Authors: Shibata Ikuya , Yoshida Tomoyuki , Baba Akio , Matsuda Haruo 
Published: May 2006

Abstract
Bu3SnH–HMPA combined system is an efficient reagent for the reduction of aldehydes. The reaction proceeds in good yields, and chemoselective carbonyl reduction is achieved for the substrate which includes another reducible group. Moreover, the intermediate, tin alkoxide, undergoes further reaction such as the preparation of ethers and heterocyclic compounds in the one pot procedure.
Zirconocene–Alkene Complexes. An X-Ray Structure and a Novel Preparative Method
Authors: Takahashi Tamotsu , Murakami Masato , Kunishige Masaki , Saburi Masahiko , Uchida Yasuzo , Kozawa Kozo , Uchida Tokiko , Swanson Douglas R , Negishi Ei-ichi 
Published: May 2006

Abstract
Structural determination of the first zirconocene–olefin complex, i.e., Cp2Zr(PhCH=CHPh)(PMe3), by X-ray crystallography is presented. Zirconium–olefin complexes such as ethylene and butene complexes can be selectively prepared in high yields from dialkylzirconocenes. On treatment of Cp2Zr(CH3)(PhCH2CH2) with, PMe3 a styrene complex 5 was obtained in good yield.
Regioisomeric 6A,6X,6Y-Tri-O-sulfonylated β-Cyclodextrin
Authors: Fujita Kahee , Tahara Tsutomu , Koga Toshitaka 
Published: May 2006

Abstract
All of five regioisomeric 6A ,6X ,6Y-tri-O-(p-toluenesulfonyl)-β-cyclodextrins were prepared, isolated, and their structures were determined through a combination of the extended Körner method, 3,6-anhydration, and the Taka amylase A-catalyzed hydrolysis.