bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessment of Exposure to Magnetic Fields in Occupational Settings
Authors: Sakurazawa Hirofumi , Iwasaki Akio , Higashi Toshiaki , Nakayama Takeo , Kusaka Yukinori 
Published: March 2004

Assessment of Exposure to Magnetic Fields in Occupational Settings: Hirofumi Sakurazawa, et al. Department of Environmental Health, School of Medicine, Fukui Medical UniversityObjectiveIt is important to have data about occupational magnetic field intensity to consider the contribution of occupational magnetic field exposure on the human body. We conducted research on exposure to occupational magnetic fields and tried to qualify data on the distribution of magnetic field’ intensity in certain general working environments with individual measurements.Subjects and MethodsWe performed sample research on the exposure to low frequency magnetic fields of workers in certain occupations and in the working environment. We also assessed the relationship between working environmental magnetic field distribution and individual exposure.ResultsSome occupations were found to be exposed to high magnetic fields. We observed that some workspaces, such as the transformer substation, generally had a uniform and high magnetic field measurement but employees were exposed to a lower intensity. We also found that welders were exposed to high magnetic fields at about 600 µT in a very short time but with a geometrical value of 0.08 µT.ConclusionThe determination of administrative levels and control levels, not only of the time weighted average of threshold limits or short term exposure limits, but also ceiling limits should be considered. More systematic research is necessary to determine variables such as operating conditions, measuring position, and frequency bands. Also, further studies will be needed to make a job‐exposure matrix for the magnetic fields for each occupation type and to combine it with exposure in non‐occupational settings such as commuting and ordinary life situations to explore the causal relationship between exposure to magnetic fields and disease.
Gene Expression of Surfactant Protein‐A and Thyroid Transcription Factor‐1 in Lungs of Rats Exposed to Silicon‐Carbide Whisker in vivo
Authors: Morimoto Yasuo , Ding Li , Oyabu Takako , Kim Heungnam , Ogami Akira , Hirohashi Masami , Nagatomo Hiroko , Yamato Hiroshi , Akiyama Izumi , Hori Hajime , Higashi Toshiaki , Tanaka Isamu 
Published: March 2004

Gene Expression of Surfactant Protein‐A and Thyroid Transcription Factor‐1 in Lungs of Rats Exposed to Silicon‐Carbide Whisker in vivo: Yasuo Morimoto, et al. Institute of Industrial and Ecological Sciences, University of Occupational and Environmental Health—Intratracheal instillation studies have shown that exposure to silicon carbide whisker (SiCW), an asbestos substitute, produces pulmonary fibrotic changes, suggesting that SICW might have a fibrogenic potential. It is thought that surfactant protein is a good biomarker of lung injury and pulmonary fibrotic activity. In order to explore whether or not surfactant protein is associated with lung disorder through exposure to SiCW, we examined the expression of SP‐A, SP‐C and thyroid transcription factor‐1 (TTF‐1), a common transcription factor of SP‐A and SP‐C mRNA in lungs exposed to SiCW. Male Wistar rats were administered 2 mg or 10 mg of SiCW suspended in saline by a single intratracheal instillation, and were sacrificed at 3 d, 1 wk, 1 month, 3 months and 6 months after the intratracheal instillation. RNA was subsequently extracted from the lungs, and expression of SP‐A, SP‐C and TTF‐1 mRNA from the lungs was observed by reverse transcriptionpolymerase chain reaction (RT‐PCR). Exposure to 2 mg of SiCW showed a decrease in mRNA of SP‐A and TTF‐1 at 6 months, but exposure to 10 mg of SiCW showed decreased levels of SP‐A and TTF‐1 mRNA at 3 d and 6 months. On the other hand, 2 mg of SiCW increased the level of SP‐C mRNA from 3 d to 3 months, and 10 mg of SiCW decreased the levels of SP‐C mRNA in the rat lungs at 3 d, 1 month and 6 months. No clear tendency to the expression of SP‐C was observed, but the patterns of expression of TTF‐1 and SP‐A were similar.These data suggest that SP‐A and TTF‐1 are associated with not only the acute phase but also the chronic phase in lungs exposed to SiCW.
Chemistry and Biology of Terpene Trilactones fromGinkgo Biloba
Authors: Strømgaard Kristian , Nakanishi Koji 
Published: March 2004

AbstractGinkgo biloba, the ginkgo tree, is the oldest living tree, with a long history of use in traditional Chinese medicine. In recent years, the leaf extracts have been widely sold as phytomedicine in Europe and as a dietary supplement worldwide. Effects ofGinkgo bilobaextracts have been postulated to include improvement of memory, increased blood circulation, as well as beneficial effects to sufferers of Alzheimer's disease. The most unique components of the extracts are the terpene trilactones, that is, ginkgolides and bilobalide. These structurally complex molecules have been attractive targets for total synthesis. Terpene trilactones are believed to be partly responsible for the neuromodulatory properties ofGinkgo bilobaextracts, and several biological effects of the terpene trilactones have been discovered in recent years, making them attractive pharmacological tools that could provide insight into the effects ofGinkgo bilobaextracts.
Synthesis and Biological Testing of Novel Analogues of Sydnone as Potential Antibacterial Agents
Authors: Moustafa Mohamed A. , Nasr Magda N. , Gineinah Magdy M. , Bayoumi Waleed A. 
Published: March 2004

AbstractSeveral series of 3‐phenylsydnone derivatives conjugated to well‐known moieties with antibacterial activity were synthesized via several routes. These derivatives include 3‐cyano‐2‐oxopyridine, 2‐amino‐3‐cyanopyridine, 2‐arylidene‐1‐ethylidenehydrazine and 2‐aroyl‐1‐ethylidenehydrazine moieties. Thus, the key intermediate 3‐(4‐acetylphenyl)sydnone (3) was allowed to react with the appropriate aldehyde, ethyl cyanoacetate or malononitrile in presence of excess ammonium acetate in two steps (method 1) or through a one‐pot reaction technique (methods 2 and 3) to give the corresponding sydnone derivatives 5 and 6, respectively. Moreover, condensation of compound 3 with hydrazine hydrate followed by the reaction with the appropriate aldehyde, mono‐ and dicarboxylic acid hydrazide yielded the corresponding sydnone derivatives 8, 9 and 10, respectively. Most of the synthesized compounds were screened for their in vitro antibacterial activity against various pathogenic organisms of both Gram‐positive and Gram‐negative bacteria. The minimum inhibitory concentrations (MICs) were determined using agar dilution method.
Maternal use of acetaminophen and nonsteroidal anti‐inflammatory drugs (NSAIDs), and muscular ventricular septal defects
Authors: Cleves Mario A. , Savell Van H. , Raj Sarika , Zhao Weizhi , Correa Adolfo , Werler Martha M. , Hobbs Charlotte A. 
Published: March 2004

AbstractBACKGROUNDMuscular ventricular septal defects (mVSDs) are the most common congenital heart defects. Previous studies have suggested maternal use of acetaminophen or nonsteroidal anti‐inflammatory drugs (NSAIDs), and/or fever as risk factors. We evaluated the association between mVSDs and maternal use of acetaminophen or NSAIDs adjusting for fever.METHODSInfants with nonsyndromic mVSDs (cases) and without birth defects (controls), with gestational age ≥37 weeks and their mothers were enrolled in the National Birth Defects Prevention Study. Two exposure periods were defined: the first trimester of pregnancy, and one month before pregnancy through delivery. Mothers reporting fever or medication use at least once during either period were considered exposed. Adjusted odds ratios and 95% confidence intervals were estimated independently for each exposure period.RESULTSThe analysis included 168 cases and 692 controls. Two case groups were evaluated: all mVSD infants (n = 168) (including those with associated minor cardiac defects or noncardiac defects), and infants with isolated mVSDs (n = 133). Mothers of cases were less likely to be African‐American than Caucasian (OR, 0.36; 95% CI, 0.18, 0.73). Approximately equal numbers of case mothers and control mothers (10.4 versus 9.7%, respectively) reported at least one febrile episode during the first trimester. Neither acetaminophen nor NSAID exposure was significantly associated with mVSDs. This was true for both case groups and both exposure periods.CONCLUSIONSSignificant associations were not detected between the occurrence of mVSDs and maternal use of NSAIDs or acetaminophen adjusting for maternal fever, nor were they detected between maternal fever and mVSDs. Birth Defects Research (Part A), 2004. Published 2004 Wiley‐Liss, Inc.
Changes in sialylation in homozygous Sp2H mouse mutant embryos
Authors: Glogarová Kateřina , Buckiová Daniela 
Published: March 2004

AbstractBACKGROUNDThe splotch (Sp2H), Pax‐3 mutant mice are characterized by neurulation defects, neural crest deficiencies, and altered somitogenesis. A link connecting all morphological abnormalities in the Pax‐3 homozygous embryos is the composition of extracellular matrix and misexpression of cell adhesion molecules. The neural cell adhesion molecule (NCAM) is one of the Pax‐3 target genes. Its adhesive properties depend on the attached polysialic acid (PSA). We have studied whether NCAM sialylation has been affected in the Pax‐3 mutant embryos.METHODSGenotyping of embryos was determined using polymerase chain reaction. The periodate‐resorcinol method was used for quantitative determination of sialic acid. Immunoblotting was used to detect sialylated NCAM isoforms and sialic acids on the blot. This antibody was also used to detect PSA‐NCAM spatial expression.RESULTSQuantitative determination of sialic acid at days 10.5–13.5 showed decreased sialic acid content in Sp2H homozygotes. The results of both techniques used in evaluating the expression of PSA‐NCAM isoforms in our study indicate that the 180‐kDa isoform is decreased in homozygous Splotch (Sp2H) embryos. Immunohistochemistry showed decreased staining in the neural tube, ganglion VIII, (day 13.5), frontal lobe, olfactory bulb, and neuroblastic retinal cells (day 18.5).CONCLUSIONSPSA‐NCAM is present in Sp2H embryos of all genotypes, starting on developmental day 9.5. Sialylation of the 180‐kDa NCAM isoform begins to decrease on day 12.5 in Sp2H homozygotes. Reduced NCAM sialylation could contribute to the decreased migration of cells in the sensory organs. Birth Defects Research (Part A), 2004. © 2004 Wiley‐Liss, Inc.
Determination of three compounds in Aloe vera by capillary electrophoresis
Authors: Yang Yifang , Wang Hongmei , Guo Lei , Chen Yi 
Published: March 2004

AbstractA capillary electrophoretic assay for determining aloe‐emodin (AE), methyl p‐coumarate (MC), and 3,4‐dihydro‐6,8‐dihydroxyl‐[(3s)‐2′‐acetyl‐3′‐hydroxyl‐5′‐methoxy‐benzyl]‐isocoumarin (DDI) in Aloe vera has been developed. Baseline separation was achieved within 15 min using a running buffer of 20 mm borax containing 10% (v/v) acetonitrile at pH 10.5. A linear relationship between the peak area and the concentration of the analytes was found in the ranges 5–500, 10–1000 and 2–1000 µg/mL for AE, MC and DDI, respectively, with correlation coefﬁcients of 0.9992–0.9998. The relative standard deviations of migration time and peak area were within 0.17–0.19 and 1.52–3.37%, respectively. The recoveries of AE, MC and DDI were 105, 102 and 96.4%. The contents of AE, MC and DDI in Aloe vera were measured to be 5.13, 0.768 and 1.30 mg/g, respectively. Copyright © 2004 John Wiley & Sons, Ltd.
Analysis of latent structures in linear models
Authors: Höskuldsson Agnar 
Published: March 2004

AbstractIn chemometrics the emphasis is on latent structure models. The latent structure is the part of the data that the modeling task is based upon. This paper addresses some fundamental issues that arise when latent structures are used. The paper consists of three parts. The first part is concerned with defining the latent structure of a linear model. Here the ‘atomic’ parts of the algorithms that generate the latent structure for linear models are analyzed. It is shown how the PLS algorithm fits within this way of presenting the numerical procedures. The second part concerns graphical illustrations, which are useful when studying latent structures. It is shown how loading weight vectors are generated and how they can be interpreted in analyzing the latent structure. It is shown how the covariance can be used to get useful a priori information on the modeling task. Some simple methods are presented for deciding whether a single or multiple latent structures should be used. The last part is about choosing the variables that should be used in the analysis. The traditional procedures for selecting variables to include in the model are presented and the insufficiencies of such approaches are demonstrated. A case study to illustrate the use of CovProc methods is presented. The CovProc methods are discussed and some of their advantages are presented. Copyright © 2004 John Wiley & Sons, Ltd.
Theory of net analyte signal vectors in inverse regression
Authors: Bro Rasmus , Andersen Charlotte M. 
Published: March 2004

AbstractThe net analyte signal and the net analyte signal vector are useful measures in building and optimizing multivariate calibration models. In this paper a theory for their use in inverse regression is developed. The theory of net analyte signal was originally derived from classical least squares in spectral calibration where the responses of all pure analytes and interferents are assumed to be known. However, in chemometrics, inverse calibration models such as partial least squares regression are more abundant and several tools for calculating the net analyte signal in inverse regression models have been proposed. These methods yield different results and most do not provide results that are in accordance with the chosen calibration model. In this paper a thorough development of a calibration‐specific net analyte signal vector is given. This definition turns out to be almost identical to the one recently suggested by Faber (Anal. Chem. 1998; 70: 5108–5110). A required correction of the net analyte signal in situations with negative predicted responses is also discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Is Water Templating Nanoporous Materials?
Authors: Henry Marc , Taulelle Francis , Loiseau Thierry , Beitone Lionel , Férey Gerard 
Published: March 2004

Abstract(H2O)17, a cluster with pentagonal water arrangements, squeezed in the sodalite cage of the crystal structure MIL‐74 (Zn6Al12P24O96⋅ [N(CH2CH2NH3)3]8⋅(H2O)34), has its oxygen atoms well located by X‐ray powder diffraction. Positioning of hydrogen atoms has been performed by a dynamic partial atomic charges and hardnesses analysis calculation, in which partial charges are recalculated for each hydrogen sub‐network modification. Hydrogen atoms are therefore positioned by energy minimization. A quantitative estimation of the hydrogen bonds energy for each Hbond and for the network in the MIL‐74 nanoporous compound has been obtained. This result allows a discussion of the effect of imprinting the nanoporous structure onto water or alternatively the templating effect of the cluster onto the inorganic framework.
Diorganotin(IV) Derivatives of Substituted Benzohydroxamic Acids with High Antitumor Activity
Authors: Li Qingshan , Guedes da Silva M. Fátima C. , Pombeiro Armando J. L. 
Published: March 2004

AbstractA series of diorganotin(IV) and dichlorotin(IV) derivatives of 4‐X‐benzohydroxamic acids, [HL1 (X = Cl) or HL2 (X = OCH3)] formulated as [R2SnL2] (R = Me, Et, nBu, Ph or Cl; L = L1 or L2), along with their corresponding mixed‐ligand complexes [R2Sn(L1)(L2)] have been prepared and characterized by FT‐IR, 1H, 13C, and 119Sn NMR spectroscopy, mass spectrometry, elemental analysis, and melting points. In addition, single‐crystal X‐ray diffraction analyses were carried out for [Me2SnL2] (L = L1 or L2), which show coordination structures intermediate between distorted octahedra and bicapped tetrahedra. The hydroxamate ligands are asymmetrically coordinated by the oxygen atoms, the carbonyl oxygen atom is further away from the metal center than the other oxygen atom. The complexes are stable monomeric species; most of them are soluble not only in chlorohydrocarbon solvents, but also in alcohols and hydroalcoholic solutions. In polar solvents, the mixed‐ligand complexes gradually decompose into the corresponding single‐ligand complex couples. The complexes exhibit in vitro antitumor activities (against a series of human tumor cell lines) which, in some cases, are identical to, or even higher than, that of cisplatin. For the dialkyltin complexes, the activity increases with the length of the carbon chain of the alkyl ligand and is higher in the case of the chloro‐substituted benzohydroxamato ligand. The [nBu2Sn(L1)2] complex displays a high in vivo activity against H22 liver and BGC‐823 gastric tumors, and has a relatively low toxicity.
Ligand Design for Alkali‐Metal‐Templated Self‐Assembly of Unique High‐Nuclearity CuII Aggregates with Diverse Coordination Cage Units: Crystal Structures and Properties
Authors: Du Miao , Bu Xian‐He , Guo Ya‐Mei , Ribas Joan 
Published: March 2004

AbstractThe construction of two unique, high‐nuclearity CuII supramolecular aggregates with tetrahedral or octahedral cage units, {(μ3‐Cl)[Li⊂ Cu4(μ‐L1)3]3}(ClO4)8(H2O)4.5 (1) and {[Na2⊂Cu12(μ‐L2)8(μ‐Cl)4](ClO4)8(H2O)10(H3O+)2}∞ (2) by alkali‐metal‐templated (Li+ or Na+) self‐assembly, was achieved by the use of two newly designed carboxylic‐functionalized diazamesocyclic ligands, N,N′‐bis(3‐propionyloxy)‐1,4‐diazacycloheptane (H2L1) or 1,5‐diazacyclooctane‐N,N′‐diacetate acid (H2L2). Complex 1 crystallizes in the trigonal R̄3c space group (a = b = 20.866(3), c = 126.26(4) Å and Z = 12), and 2 in the triclinic P$\bar 1$ space group (a = 13.632(4), b = 14.754(4), c = 19.517(6) Å, α = 99.836(6), β = 95.793(5), γ = 116.124(5)° and Z = 1). By subtle variation of the ligand structures and the alkali‐metal templates, different polymeric motifs were obtained: a dodecanuclear architecture 1 consisting of three Cu4 tetrahedral cage units with a Li+ template, and a supramolecular chain 2 consisting of two crystallographically nonequivalent octahedral Cu6 polyhedra with a Na+ template. The effects of ligand functionality and alkali metal template ions on the self‐assembly processes of both coordination supramolecular aggregates, and their magnetic behaviors are discussed in detail.
Multistate/Multifunctional Behaviour of 4′‐Hydroxy‐6‐nitroflavylium: A Write‐Lock/Read/Unlock/Enable‐Erase/Erase Cycle Driven by Light and pH Stimulation
Authors: Moncada Margarida C. , Parola A. Jorge , Lodeiro Carlos , Pina Fernando , Maestri Mauro , Balzani Vincenzo 
Published: March 2004

AbstractWe have investigated the network of reactions observed for the photochromic 4′‐hydroxy‐6‐nitroflavylium compound in aqueous solutions upon pH changes (including pH jump and stopped flow experiments) and light excitation. The changes observed in the NMR and UV/Vis spectra allowed identification of ten different forms in which this compound can be transformed depending on the experimental conditions. Equilibrium and kinetic constants have been determined. Compared with other members of the flavylium family, 4′‐hydroxy‐6‐nitroflavylium is characterized by a large cis→trans isomerization barrier, and a very efficient hydration reaction. These peculiar features allow writing, reading, storing and erasing photonic information on 4′‐hydroxy‐6‐nitroflavylium by a novel cyclic process that involves the following steps: write‐lock/read/unlock/enable‐erase/erase.
Synthesis and Characterization of Dendritic Multichromophores Based on Rylene Dyes for Vectorial Transduction of Excitation Energy
Authors: Weil Tanja , Reuther Erik , Beer Cornelia , Müllen Klaus 
Published: March 2004

AbstractThe synthesis of dendritic multichromophores based on a rigid polyphenylene scaffold is presented. Different rylene chromophores are incorporated into the core, the branches, and the surface of the dendrimer. In this way, two generations of dendritic dyads consisting of a terrylenediimide core, a stiff polyphenylene scaffold, and a perylenemonoimide periphery were obtained. Furthermore, the first synthetic approach to a dendritic triad is introduced. The outer sphere of this macromolecule is formed by naphthalenemonoimide chromophores, whereas perylenemonoimide groups are located in the dendritic scaffold, and the terrylenediimide chromophore serves as a core molecule. This multichromophore absorbs over the whole range of the visible spectrum and shows well‐separated absorption envelopes. In the course of dendrimer synthesis new attempts towards a straightforward functionalization strategy for rylene dyes are also presented.
Mechanism of the Reaction of the [W3S4H3(dmpe)3]+ Cluster with Acids: Evidence for the Acid‐Promoted Substitution of Coordinated Hydrides and the Effect of the Attacking Species on the Kinetics of Protonation of the Metal‐Hydride Bonds
Authors: Basallote Manuel G. , Feliz Marta , Fernández‐Trujillo M. Jesús , Llusar Rosa , Safont Vicent S. , Uriel Santiago 
Published: March 2004

AbstractThe cluster [W3S4H3(dmpe)3]+ (1) (dmpe=1,2‐bis(dimethylphosphino)ethane) reacts with HX (X=Cl, Br) to form the corresponding [W3S4X3(dmpe)3]+ (2) complexes, but no reaction is observed when 1 is treated with an excess of halide salts. Kinetic studies indicate that the hydride 1 reacts with HX in MeCN and MeCN–H2O mixtures to form 2 in three kinetically distinguishable steps. In the initial step, the WH bonds are attacked by the acid to form an unstable dihydrogen species that releases H2 and yields a coordinatively unsaturated intermediate. This intermediate adds a solvent molecule (second step) and then replaces the coordinated solvent with X− (third step). The kinetic results show that the first step is faster with HCl than with solvated H+. This indicates that the rate of protonation of this metal hydride is determined not only by reorganization of the electron density at the MH bonds but also by breakage of the HX or H+solvent bonds. It also indicates that the latter process can be more important in determining the rate of protonation.