bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mineralogical characteristics and micromorphological observations of brittle/soft Fe/Mn concretions from Okinawan soils
Authors: Vidhana Arachchi L. P. , Tokashiki Y. , Baba S. 
Published: August 2004

AbstractManganese minerals are not common and the distinction of poorly crystalline Mn minerals from other associated minerals is important. For many years, the crystal structures of poorly crystalline Mn minerals in Fe/Mn concretions have been the subject of considerable conjecture and controversy. This study reports the micromorphological and mineralogical characteristics, and the chemical composition of Fe/Mn minerals in soft Fe/Mn concretions formed in Shimajiri Mahji soils (Typic Hapludalfs) that developed from Ryukyu limestone on Okinawa Island, Japan. The Fe/Mn minerals in brittle/soft Fe/Mn concretions were characterized using a sequential selective dissolution procedure (SSDP) by treatments with NaOH, hydroxylamine hydrochloride (HAHC) at 25°C and 60°C, and dithionite-citrate-bicarbonate (DCB) in combination with X-ray diffraction (XRD) and scanning electron microscopy (SEM). The HAHC treatment at 25°C dissolved birnessite, but not lithiophorite and goethite. A subsequent extraction with HAHC at 60°C dissolved lithiophorite but not goethite. Finally, the DCB treatment was able to dissolve goethite. The SEM images show that birnessite crystals, with a blade- or plate-like habit, form globular aggregates inside veins and cavities. Pseudo-hexagonal crystals of lithiophorite have produced thread-ball structures with crystal shape similar to birnessite and birnessite crystals are closely associated with lithiophorite. Well developed hexagonal plates of gibbsite crystals are clustered in different directions to make foliated vermiform structures. Aggregates of goethite crystals are acicular and are arranged into stars. The supplementary SSDP, in combination with XRD and SEM techniques, provides methods to distinguish and partly quantify birnessite and lithiophorite in the presence of layer silicate and Fe oxide minerals and confirm their own morphological features.
A Short and Efficient Methodology for the Synthesis of Novel 3‐Aryloxazolidin‐2‐one Derivatives
Authors: Nandakumar Mecheril V. 
Published: August 2004

AbstractAn efficient synthesis of novel oxazolidinone derivatives is disclosed. Novel oxazolidinone derivatives were synthesized by a copper‐catalyzed N‐arylation reaction with control of the substituents on both the sides of the phenyl ring.
Direct Sulfonation of Methane to Methanesulfonic Acid by Sulfur Trioxide Catalyzed by Cerium(IV) Sulfate in the Presence of Molecular Oxygen
Authors: Mukhopadhyay Sudip , Bell Alexis T. 
Published: August 2004

AbstractDirect sulfonation of methane with SO3 to methanesulfonic acid (MSA) is accomplished in sulfuric acid with almost 100% selectivity in the presence of a catalyst, namely, Ce and Rh salts and molecular oxygen as the catalyst regenerator. In the absence of O2, the catalyst remains effective but the selectivity to MSA decreases to 53% and byproducts, principally CH3OSO3H, are formed. The effects of O2 pressure, catalyst concentration, temperature, SO3 concentration, and methane pressure have been examined on the rate of SO3 conversion to MSA. The conversion of SO3 to MSA was the same when CF3SO3H was used as the solvent instead of H2SO4.
The Art of Meeting Palladium Specifications in Active Pharmaceutical Ingredients Produced by Pd‐Catalyzed Reactions
Authors: Garrett Christine E. , Prasad Kapa 
Published: August 2004

AbstractThe use of palladium‐derived catalysts in the synthesis of fine chemicals, pharmaceutical intermediates and active pharmaceutical ingredients (APIs) has become quite common in the last few decades. The number of palladium‐catalyzed synthetic reactions (both achiral and chiral) available to chemists has provided access to more complex structures in fewer steps and with less waste, due to the catalytic nature of many of the methods. An unfortunate side effect of using palladium is the potential for palladium‐containing impurities to remain in the desired compound after isolation. This is an especially significant problem for the pharmaceutical industry since there is a low limit for heavy metal impurities allowed in the drug substance. Therefore, various methods of removing palladium impurities from organic compounds of pharmaceutical interest have been developed. This review will provide a survey of the published methods but is not meant to be inclusive of all published material in this area of research.
Prospective study of contrast-enhanced computed tomography, computed tomography during arterioportography, and magnetic resonance imaging for staging colorectal liver metastases for liver resection
Authors: Bhattacharjya S , Bhattacharjya T , Baber S , Tibballs J M , Watkinson A F , Davidson B R 
Published: August 2004

Abstract

Background
This study compared the value of contrast-enhanced helical computed tomography (CT), CT during arterioportography (CTAP), and contrast-enhanced magnetic resonance imaging (MRI) for staging patients with colorectal liver metastases.

Methods
One hundred and twenty patients with known or suspected colorectal liver metastases were evaluated prospectively. MRI and CTAP were performed within 3 weeks of CT in patients with potentially resectable tumours. Results of imaging were compared with findings at surgery, intraoperative ultrasonography and histological examination.

Results
Twenty patients were not considered for liver resection following CT. The remaining 100 patients underwent CT and CTAP, 85 of whom had CT, CTAP and MRI. The sensitivity and specificity were 73·0 and 96·5 per cent for CT, 87·1 and 89·3 per cent for CTAP, and 81·9 and 93·2 per cent for MRI. Positive predictive values were 89·7, 87·5 and 87·5 per cent respectively. Receiver–operator characteristic analysis gave an accuracy on a segment-by-segment analysis of 0·73 for CT, 0·87 for CTAP and 0·82 for MRI. Combining information from CT and CTAP, CT and MRI, or all three modalities, did not significantly increase the percentage of patients staged correctly (71, 72 and 76 per cent respectively).

Conclusion
The diagnostic accuracy of spiral CT, MRI and CTAP was similar. Combining modalities did not improve accuracy.
The Calculation of Indirect Nuclear Spin–Spin Coupling Constants in Large Molecules
Authors: Watson Mark A. , Sałek Paweł , Macak Peter , Jaszuński Michał , Helgaker Trygve 
Published: August 2004

AbstractWe present calculations of indirect nuclear spin–spin coupling constants in large molecular systems, performed using density functional theory. Such calculations, which have become possible because of the use of linear‐scaling techniques in the evaluation of the Coulomb and exchange‐correlation contributions to the electronic energy, allow us to study indirect spin–spin couplings in molecules of biological interest, without having to construct artificial model systems. In addition to presenting a statistical analysis of the large number of short‐range coupling constants in large molecular systems, we analyse the asymptotic dependence of the indirect nuclear spin–spin coupling constants on the internuclear separation. In particular, we demonstrate that, in a sufficiently large one‐electron basis set, the indirect spin–spin coupling constants become proportional to the inverse cube of the internuclear separation, even though the diamagnetic and paramagnetic spin‐orbit contributions to the spin–spin coupling constants separately decay as the inverse square of this separation. By contrast, the triplet Fermi contact and spin‐dipole contributions to the indirect spin–spin coupling constants decay exponentially and as the inverse cube of the internuclear separation, respectively. Thus, whereas short‐range indirect spin–spin coupling constants are usually dominated by the Fermi contact contribution, long‐range coupling constants are always dominated by the negative diamagnetic spin‐orbit contribution and by the positive paramagnetic spin‐orbit contribution, with small spin‐dipole and negligible Fermi contact contributions.
The Induced Magnetic Field in Cyclic Molecules
Authors: Merino Gabriel , Heine Thomas , Seifert Gotthard 
Published: August 2004

AbstractThe response of a molecule to an applied external magnetic field can be evaluated by a graphical representation of the induced magnetic field. We have applied this technique to four representative, cyclic organic molecules, that is, to aromatic (C6H6, D6h), anti‐aromatic (C4H4, D2h) and non‐aromatic (C4H8, D4h, and C6H12, D3d) molecules. The results show that molecules that contain a π system possess a long‐range magnetic response, while the induced magnetic field is short‐range for molecules without π systems. The induced magnetic field of aromatic molecules shields the external field. In contrast, the anti‐aromatic molecules increase the applied field inside the ring. Aromatic, anti‐aromatic, and non‐aromatic molecules can be characterized by the appearance of the magnetic response. We also show that the magnetic response is directly connected to nucleus‐independent chemical shifts (NICS).
Quantitative, not qualitative, differences in CD8+ T cell responses to Theiler's murine encephalomyelitis virus between resistant C57BL/6 and susceptible SJL/J mice
Authors: Lyman Michael A. , Myoung Jinjong , Mohindru Mani , Kim Byung S. 
Published: August 2004

AbstractTheiler's murine encephalomyelitis virus (TMEV) infection of the CNS induces an immune‐mediated demyelinating disease in susceptible mouse strains and serves as a relevant infection model for human multiple sclerosis. However, it is not yet clear what immunological parameters determine the susceptibility of SJL/J mice compared to resistant mice. We have here compared the TMEV‐specific CD8+ T cell responses in highly susceptible SJL/J mice with those of highly resistant C57BL/6 mice. Our results clearly indicate that the levels of initial responses of infiltrating CD8+ T cells to viral capsid proteins are higher in resistant C57BL/6 mice compared to susceptible SJL/J mice. However, the level of virus‐specific CD8+ T cells was much more rapidly reduced in resistant C57BL/6, resulting in a higher CD8+ T cell level in SJL/J mice later in viral infection. The activation states, cytokine production, as well as the cytolytic function of the CD8+ T cells were similar to each other in these mice. These results suggest that an initial induction of a vigorous CD8+ T cell response to TMEV is critically important for the resistance to virally induced demyelinating disease.
BAFF binding to T cell‐expressed BAFF‐R costimulates T cell proliferation and alloresponses
Authors: Ye Qunrui , Wang Liqing , Wells Andrew D. , Tao Ran , Han Rongxiang , Davidson Anne , Scott Martin L. , Hancock Wayne W. 
Published: August 2004

AbstractBinding of the TNF family member, B cell activating factor (BAFF), to its receptor (BAFF‐R, TNFRSF13C) is required for generation and maintenance of mature B cells, but there are no data as to any role for the BAFF/BAFF‐R pathway in T cell functions. We report that the binding of BAFF to BAFF‐R expressed by a subset of primarily CD4+ T cells costimulates T cell activation and allo‐proliferation in vitro and in vivo, and that mice with a mutation in the BAFF‐R, or with a targeted deletion of BAFF, show prolonged cardiac allograft survival as compared to wild‐type or transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI)–/– controls. Taken together, these data indicate the BAFF/BAFF‐R pathway contributes to both T and B cell responses and may be an attractive target for control of acute and chronic allograft rejection.
Dissecting cytotoxic T cell responses towards the NY‐ESO‐1 protein by peptide/MHC‐specific antibody fragments
Authors: Held Gerhard , Matsuo Mitsutoshi , Epel Malka , Gnjatic Sacha , Ritter Gerd , Lee Sang Yull , Tai Tsin Yee , Cohen Cyril J. , Old Lloyd J. , Pfreundschuh Michael , Reiter Yoram , Hoogenboom Hennie R. , Renner Christoph 
Published: August 2004

AbstractNY‐ESO‐1 is a germ cell antigen aberrantly expressed by different tumor types that elicits strong humoral and cellular immune responses, representing one of the most promising candidates for vaccination of cancer patients. A detailed analysis of CD8+ T cells generated in vaccine trials using NY‐ESO‐1‐derived peptides (157–165 and 157–167) revealed that the dominant immune response was directed against a cryptic epitope (159–167) diverting the immune response from tumor recognition. Only CTL reactivity to the NY‐ESO‐1157–165 peptide appeared to be capable of lysing NY‐ESO‐1/HLA‐A0201‐expressing tumor cells. To study the process of NY‐ESO‐1 peptide presentation by tumor cells in more detail we generated a high‐affinity (KD=60 nM) antibody fragment that specifically recognizes the NY‐ESO‐1157–165 peptide/HLA‐A0201 complex. Peptide variants such as the NY‐ESO‐1157–167 peptide or the cryptic NY‐ESO‐1159–167 peptide were not recognized. The antibody fragment blocked in a dose‐dependent fashion the recognition of NY‐ESO‐1/HLA‐A2‐positive tumor cells by NY‐ESO‐1157–165 peptide‐specific CD8+ T cells. This antibody fragment is a novel reagent that binds with TCR‐like specificity to the NY‐ESO‐1157–165/HLA‐A2 complex thus distinguishing between CTL responses against immunological meaningful or cryptic NY‐ESO‐1‐derived peptides. It may therefore become a useful monitoring tool for the development of NY‐ESO‐1‐based cancer vaccines.
Arginine and glutamine availability and macrophage functions in the obese insulin‐resistant Zucker Rat
Authors: Blanc Marie‐Céline , Moinard Christophe , Béziel Aurélie , Darquy Sylviane , Cynober Luc , De Bandt Jean‐Pascal 
Published: August 2004

AbstractIncreased susceptibility to infections in obese patients may be related to decreased availability of arginine and glutamine, which may affect immune cell functions. Our aim was to evaluate the in vitro effects of these amino acids on the function of macrophages from obese insulin‐resistant Zucker rats. Macrophages, isolated from male Zucker obese or lean rats by peritoneal lavage, were incubated in Dulbecco's modified Eagle medium (DMEM) without arginine or glutamine. Arginine or glutamine was added to the medium at increasing final concentrations (0, 0.25, 0.5, 1 or 2 mM). After stimulation by lipopolysaccharide (LPS) from E. coli (40 μg/ml), productions of tumour necrosis factor α (TNFα) and of nitric oxide (NO) were measured after 3 or 48 h incubation, respectively. NO production, lower in macrophages from obese rats, decreased in macrophages from lean rats (0 mM: 2,423 ± 1,174 vs. 2 mM: 198 ± 31 μM/mg protein/24 h; P < 0.05), but not in those from obese rats, when glutamine was added. TNFα production, lower in macrophages from obese rats, was inversely correlated with glutamine concentration. In the presence of arginine, NO production was constantly higher in macrophages from obese rats. It peaked at 0.5 mM arginine and decreased thereafter in both groups. TNFα production in macrophages from lean rats was unaffected by arginine, but decreased in macrophages from obese rats (0 mM: 1920 ± 450 vs. 2 mM: 810 ± 90 μM/mg protein/3 h; P < 0.05). These results suggest that abnormalities in cell signalling or in arginine and glutamine metabolism in macrophages of obese rats, resulting in decreased TNFα production and increased NO release, may contribute to increased susceptibility to infection in insulin‐resistant states. © 2005 Wiley‐Liss, Inc.
Involvement of p42/p44 MAPK, JNK, and NF‐κB in IL‐1β‐induced ICAM‐1 expression in human pulmonary epithelial cells
Authors: Lin Feng‐Shu , Lin Chih‐Chung , Chien Chin‐Sung , Luo Shu‐Feng , Yang Chuen‐Mao 
Published: August 2004

AbstractInterleukin‐1β (IL‐1β) has been shown to induce the expression of intercellular adhesion molecule‐1 (ICAM‐1) on airway epithelial cells and contributes to inflammatory responses. However, the mechanisms regulating ICAM‐1 expression by IL‐1β in human A549 cells was not completely understood. Here, the roles of mitogen‐activated protein kinases (MAPKs) and NF‐κB pathways for IL‐1β‐induced ICAM‐1 expression were investigated in A549 cells. IL‐1β induced expression of ICAM‐1 protein and mRNA in a time‐ and concentration‐dependent manner. The IL‐1β induction of ICAM‐1 mRNA and protein were partially inhibited by U0126 and PD98059 (specific inhibitors of MEK1/2) and SP600125 [a specific inhibitor of c‐Jun‐N‐terminal kinase (JNK)]. U0126 was more potent than other inhibitors to attenuate IL‐1β‐induced ICAM‐1 expression. Consistently, IL‐1β stimulated phosphorylation of p42/p44 MAPK and JNK which was attenuated by pretreatment with U0126 or SP600125, respectively. Moreover, transfection with dominant negative mutants of MEK1/2 (MEK K97R) or ERK2 (ERK2 K52R) also attenuated IL‐1β‐induced ICAM‐1 expression. The combination of PD98059 and SP600125 displayed an additive effect on IL‐1β‐induced ICAM‐1 gene expression. IL‐1β‐induced ICAM‐1 expression was almost completely blocked by a specific NF‐κB inhibitor helenalin. Consistently, IL‐1β stimulated translocation of NF‐κB into the nucleus and degradation of IκB‐α which was blocked by helenalin, U0126, or SP600125. Taken together, these results suggest that activation of p42/p44 MAPK and JNK cascades, at least in part, mediated through NF‐κB pathway is essential for IL‐1β‐induced ICAM‐1 gene expression in A549 cells. These results provide new insight into the mechanisms of IL‐1β action that cytokines may promote inflammatory responses in the airway disease. © 2004 Wiley‐Liss, Inc.
Preferential production of latent transforming growth factor β‐2 by primary prostatic epithelial cells and its activation by prostate‐specific antigen
Authors: Dallas S.L. , Zhao S. , Cramer S.D. , Chen Z. , Peehl D.M. , Bonewald L.F. 
Published: August 2004

AbstractThree mammalian isoforms of transforming growth factor‐β (TGFβ) are known, TGFβ1, 2, and 3, that have non‐overlapping functions during development. However, their specific roles in cancers such as prostate cancer are less clear. Here we show that primary cultures of prostatic epithelial cells preferentially produce and activate the latent TGFβ2 isoform. Paired cultures of normal and malignant prostate cells from prostate cancer patients produced predominantly the TGFβ2 isoform, with 30‐ to 70‐fold less TGFβ1. By mono‐Q ion exchange chromatography, three major peaks of latent TGFβ2 activity were observed corresponding to the known small latent TGFβ2 complex, the known large latent TGFβ2 complex and a novel eluting peak of latent TGFβ2. Although prostate cells are known to activate latent TGFβ, the mechanism for activation is currently unclear. We investigated whether prostate specific antigen (PSA), a serine protease used as a clinical marker for prostate cancer, could play a role in the activation of latent TGFβ. Unlike plasmin, a known activator of both latent TGFβ1 and 2, PSA specifically activated the recombinant small latent form of TGFβ2, but not TGFβ1. Prostate epithelial cells, therefore, preferentially produce the TGFβ2 isoform and PSA, a protease produced by the prostate, specifically targets the activation of this TGFβ isoform. PSA‐mediated activation of latent TGFβ2 may be an important mechanism for autocrine TGFβ regulation in the prostate and may potentially contribute to the formation of osteoblastic lesions in bone metastatic prostate cancer. © 2004 Wiley‐Liss, Inc.
Effects of thermal food processing on the chemical structure and toxicity of fumonisin mycotoxins
Authors: Humpf Hans‐Ulrich , Voss Kenneth A. 
Published: August 2004

AbstractFumonisins are Fusarium mycotoxins that occur in corn and corn‐based foods. They are toxic to animals and at least one analogue, fumonisin B1, is carcinogenic to rodents. Their effect on human health is unclear, however, fumonisins are considered to be risk factors for cancer and possibly neural tube defects in some heavily exposed populations. It is therefore important to minimize exposures in these populations. Cleaning corn to remove damaged or moldy kernels reduces fumonisins in foods while milling increases their concentration in some and reduces their concentration in other products. Fumonisins are water‐soluble and nixtamalization (cooking in alkaline water) lowers the fumonisin content of food products if the cooking liquid is discarded. Baking, frying, and extrusion cooking of corn at high temperatures (⪈ 190°C) also reduces fumonisin concentrations in foods, with the amount of reduction achieved depending on cooking time, temperature, recipe, and other factors. However, the chemical fate of fumonisins in baked, fried, and extruded foods is not well understood and it is not known if the reduced concentrations result from thermal decomposition of fumonisins or from their binding to proteins, sugars or other compounds in food matrices. These possibilities might or might not be beneficial depending upon the bioavailability and inherent toxicity of decomposition products or the degree to which bound fumonisins are released in the gastrointestinal tract. In this review the affects of cooking and processing on the concentration and chemical structure of fumonisins as well as the toxicological consequences of known and likely fumonisin reaction products are discussed.
Self‐assembly structure of the levulinic acid–melamine lattice
Authors: Venkatraman Ramaiyer , Ray Paresh Chandra , Choi Chan Soo 
Published: August 2004

AbstractEquimolar amounts of levulinic acid and melamine formed a self‐assembled unit through a hydrogen‐bonding network. Room‐temperature single‐crystal diffraction studies and FTIR spectroscopy of the system indicated adduct formation between melamine and levulinic acid. Ab initio Hartree–Fock (HF) and density functional theory (DFT) calculations, using the 6‐31G(d,p) basis set, have been performed to investigate the gas‐phase structure and IR frequencies. The theoretical parameters (geometry and vibrational frequencies) predicted by HF and DFT methods for the adduct are in good agreement with the experimental data. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Is the isotopic composition of nitrous oxide an indicator for its origin from nitrification or denitrification? A theoretical approach from referred data and microbiological and enzyme kinetic aspects
Authors: Schmidt Hanns‐Ludwig , Werner Roland A. , Yoshida Naohiro , Well Reinhard 
Published: August 2004

AbstractLiterature data on the isotopic composition of nitrous oxide indicate a general predominance of the α‐15N‐isotopomer and a parallel 18O‐enrichment in N2O from nitrification and denitrification, respectively. As the kinetic isotope effects on any individual reactions of the two processes lead to depletions of the heavy isotopes of nitrogen and oxygen in the products, the observed enrichments could mainly be caused by enzymatic reduction of NO, provided it occurs via a symmetric intermediate like hyponitrite; infrared data are in favour of large differences between the binding constants of the isotopomers and isotopologues of this compound. As a matter of fact one of the mechanisms discussed for the nitric oxide reductase from certain microorganisms implies the parallel binding of two NO molecules and the formation of a symmetrical intermediate, while that of the enzyme from other microorganisms reduces NO in a sequential mechanism. In addition, isotope effects on the reduction of N2O to N2 must contribute to the observed isotope characteristics of N2O, especially in context with denitrification. Therefore, the known enzymatic reaction pathways suggest that the α‐15N‐isotopomer preference and the 18O‐signature of the produced N2O is not essentially characteristic for its origin from nitrification or denitrification, respectively, but rather from the involved population of microorganisms and the type of their nitric oxide reductases. This has to be confirmed experimentally. Copyright © 2004 John Wiley & Sons, Ltd.