bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrogenation of Citral using Monometallic Pt and Bimetallic Pt‐Ru Catalysts on a Mesoporous Support in Supercritical Carbon Dioxide Medium
Authors: Chatterjee M. , Zhao F. Y. , Ikushima Y. 
Published: April 2004

AbstractSupercritical carbon dioxide was shown to be a suitable reaction medium for the highly efficient hydrogenation of citral using monometallic Pt and bimetallic Pt‐Ru supported on a mesoporous material, MCM‐48, as catalyst. A remarkable change in the product distribution was observed after the addition of Ru to the monometallic Pt catalyst in supercritical carbon dioxide. The monometallic Pt catalyst was found to be highly selective to the unsaturated alcohol (geraniol+nerol) at a temperature of 323 K within 2 h whereas the bimetallic catalyst becomes selective to the partially saturated aldehyde (citronellal) under the same reaction conditions. Phase behavior plays an important role in the product distribution. Highest conversion and high selectivity to citronellal were achieved in the homogeneous phase for the Pt‐Ru catalyst while on the other hand the unsaturated alcohol (geraniol+nerol) was produced in the heterogeneous phase for the monometallic Pt catalyst. An XPS study offers strong evidence of the electronic modification of Pt after the addition of Ru in the bimetallic catalyst. The change in product distribution on the Pt‐Ru bimetallic catalyst may be explained by the appreciable interaction between the medium and the metal particles promoted by the presence of metallic Ru.
Synthesis of Thiiranes from Oxiranes in the Presence of β‐Cyclodextrin in Water
Authors: Srilakshmi Krishnaveni N. , Surendra K. , Somi Reddy M. , Nageswar Y. V. D. , Rama Rao K. 
Published: April 2004

AbstractA mild and highly efficient, user‐friendly procedure has been developed for the conversion of oxiranes to thiiranes under supramolecular catalysis in the presence of β‐cyclodextrin in water at ambient temperature in excellent yields. The use of β‐cyclodextrin in this transformation overcomes the use of heavy metal halides as promoters and chlorinated hydrocarbons and other hazardous organic solvents.
The Absolute Configuration of the Products of the Enantioselective Rhodium(I)/BINAP‐Catalyzed Enyne Cyclization
Authors: Hashmi A. Stephen K. , Haufe Patrick , Rivas Nass Andreas , Bats Jan W. 
Published: April 2004

AbstractThe absolute configuration of the product 7 obtained from a rhodium‐catalyzed enyne cyclization of 6 with the (R)‐BINAP ligand was determined by anomalous diffraction in the X‐ray crystal structure analysis.
Model of adsorption–reaction–desorption in a swarm of spheroidal particles
Authors: Coutelieris F. A. , Burganos V. N. , Payatakes A. C. 
Published: April 2004

AbstractThe mass transport problem from a Newtonian fluid to a swarm of prolate or oblate spheroidal adsorbing particles under creeping flow conditions is considered here. The spheroidal‐in‐cell model is used for the analytical description of the flow field within the swarm. A realistic adsorption–reaction–desorption mechanism is used to describe the adsorption of mass on the particle surface, instead of the assumption of instantaneous adsorption that has been adopted previously. The convective diffusion equation accompanied by the appropriate boundary conditions is solved analytically for the case of high Peclet numbers and numerically for the low ones. In both cases, analytical expressions for the overall Sherwood number, the adsorption rate, and the mass transport coefficient were obtained. It was found that the adsorption rate is higher for oblate shapes and for diffusional, instead of convectional, environments. Finally, the assumption of instantaneous adsorption leads to values for the overall Sherwood number and the adsorption efficiency that are 15–50% lower and 10–35% higher, respectively, than those obtained by using the more realistic adsorption–reaction–desorption model. © 2004 American Institute of Chemical Engineers AIChE J, 50: 779–785, 2004
New sorbents for desulfurization of diesel fuels via π‐complexation
Authors: Hernández‐Maldonado Arturo J. , Yang Ralph T. 
Published: April 2004

AbstractDesulfurization of a commercial diesel fuel by different adsorbents was studied in a fixed‐bed adsorber operated at ambient temperature and pressure. In general, the adsorbents tested for total sulfur adsorption capacity at breakthrough followed the order: AC/Cu(I)‐Y > Cu(I)‐Y > Selexsorb® CDX (alumina) > CuCl/γ‐Al2O3 > activated carbon > Cu(I)‐ZSM‐5. The best adsorbent, AC/Cu(I)‐Y (layered bed of 15 wt % activated carbon followed by Cu(I)Y), is capable of producing 30 cm3 of diesel fuel per gram of adsorbent with a weighted average content of 0.15 ppmw‐S, and about 20 cm3 of diesel fuel per gram of adsorbent with a weighted average content of 0.06 ppmw‐S. These low‐sulfur fuels are suitable for fuel cell applications. The added layer of carbon not only delayed the sulfur breakthrough significantly but also sharpened the sulfur wavefronts. GC‐FPD results showed that the π‐complexation sorbents selectively adsorbed highly substituted thiophenes, benzothiophenes, and dibenzothiophenes from diesel, which is not possible with conventional hydrodesulfurization (HDS) reactors. The high sulfur selectivity and high sulfur capacity of Cu(I)Y were because of π‐complexation. © 2004 American Institute of Chemical Engineers AIChE J, 50: 791–801, 2004
Chlorophenol exposure in harbor workers exposed to river silt aerosols
Authors: Radon Katja , Wegner Ralf , Heinrich‐Ramm Regine , Baur Xaver , Poschadel Bernd , Szadkowski Dieter 
Published: April 2004

AbstractObjectivesWhile dredging the river Elbe in the harbor of Hamburg, workers are potentially exposed to river silt aerosols containing organic compounds. The aim of this cross‐sectional study was to determine the internal load of chlorophenols in exposed workers.MethodsEighty‐four exposed workers and eighty‐four unexposed office workers were examined. Urinary samples were analyzed for dichlorophenols, trichlorophenols, tetrachlorophenols, and pentachlorophenol (PCP).ResultsFor exposed workers, more than 2/3 of the urinary samples were above detection limit for 2,5‐dichlorophenol, 2,4/3,4‐dichlorophenol, 2,4,6‐trichlorophenol, and PCP. Harbor workers had significantly higher median levels of 2,5‐dichlorophenol (0.6 vs. 0.4 µg/g creatinine) and PCP (1.4 vs. 1.0 µg/g creatinine) as compared to unexposed subjects. These differences remained statistically significant after adjustment for age, smoking habits, and fish consumption.ConclusionHarbor workers in the harbor of Hamburg have a statistically significant higher internal load of chlorophenols than the general population. However, the internal load is within the range of exposure reported from the general population. Therefore, even though chlorophenols are found in the river silt these exposures do not seem to be the major source of the internal load among workers in the harbor of Hamburg. Am. J. Ind. Med. 45:440–445, 2004. © 2004 Wiley‐Liss, Inc.
Involuntary job loss as a risk factor for subsequent myocardial infarction and stroke: Findings from The Health and Retirement Survey
Authors: Gallo William T. , Bradley Elizabeth H. , Falba Tracy A. , Dubin Joel A. , Cramer Laura D. , Bogardus Sidney T. , Kasl Stanislav V. 
Published: April 2004

AbstractBackgroundThe role of stress in the development of cardiovascular disease is well established. Previous research has demonstrated that involuntary job loss in the years immediately preceding retirement can be a stressful life event shown to produce adverse changes in physical and affective health. The objective of this study was to estimate the risk of myocardial infarction (MI) and stroke associated with involuntary job loss among workers nearing retirement in the United States.MethodsWe used multivariable survival analysis to analyze data from the first four waves of the Health and Retirement Survey (HRS), a nationally representative sample of older individuals in the US. The analytic sample includes 457 workers who experienced job loss and a comparison group of 3,763 employed individuals.ResultsThe results indicate that involuntary job loss is not associated with subsequent risk of MI (adjusted HR = 1.89; 95% CI = 0.91, 3.93); the risk of subsequent stroke associated with involuntary job loss is more than double (adjusted HR = 2.64; 95% CI = 1.01, 6.94).ConclusionsOur findings present new data to suggest that involuntary job loss should be considered as a plausible risk factor for subsequent cardiovascular and cerebrovascular illness among older workers. Am. J. Ind. Med. 45:408–416, 2004. © 2004 Wiley‐Liss, Inc.
An assessment of the effects of increased regulatory enforcement and legislative reform on occupational hearing loss workers' compensation claims: Oregon 1984–1998
Authors: McCall Brian P. , Horwitz Irwin B. 
Published: April 2004

AbstractBackgroundHearing loss from occupational exposures is a serious and widespread problem. This study measured the outcomes that increased enforcement of regulations and legislative interventions had on hearing loss workers' compensation claims.MethodsWorkers' compensation claim data from Oregon was analyzed for the period of 1984–1998 to examine trends and severity of hearing loss claims. In 1987 and 1990, Oregon enacted legislative reforms to improve enforcement and promulgation of safety standards in the state. This study examined hearing loss claims between the periods of pre‐ and post‐legislative reforms.ResultsIt was found that hearing loss claims decreased significantly following the legislative reforms, although the average cost per claim increased. Age and tenure effects, and evidence of moral hazard were also discovered.ConclusionsIncreased enforcement of regulations and legislative interventions by Oregon improved working conditions leading to occupational hearing loss. Nevertheless, hearing loss remains problematic, and continued efforts are required to improve worker safety. Am. J. Ind. Med. 45:417–427, 2004. © 2004 Wiley‐Liss, Inc.
Duplication of the distal long arm of chromosome 15: Report of three new patients and review of the literature
Authors: Roggenbuck Jennifer A. , Mendelsohn Nancy J. , Tenenholz Beverly , Ladda Roger L. , Fink James M. 
Published: April 2004

AbstractPatients with trisomies or duplications of distal 15q have rarely been reported in the literature. Previous authors [Zollino et al., 1999: Am J Med Genet 87:391–394] have described a distal 15q trisomy syndrome, including the unusual features of prenatal overgrowth, tall stature, macrocephaly, and craniosynostosis. We report three new patients with a duplication of 15q24‐q26.3; features common to the two surviving patients include ptosis, small size, and developmental delay. None of these patients had craniosynostosis or overgrowth. We propose that the previously described distal 15q trisomy syndrome [Zollino et al., 1999: Am J Med Genet 87:391–394] may result from specific disruption of a gene linked to 15q25, rather than partial trisomy for the region. © 2003 Wiley‐Liss, Inc.
Does autosomal dominant pseudoxanthoma elasticum exist?
Authors: Plomp Astrid S. , Hu Xiaofeng , de Jong Paulus T.V.M. , Bergen Arthur A.B. 
Published: April 2004

AbstractPseudoxanthoma elasticum (PXE) is a progressive disorder of elastic fibers in skin, eyes, and arterial walls. It is caused by mutations in the ABCC6 gene. Most patients are sporadic cases. The majority of familial cases show autosomal recessive (AR) inheritance, but autosomal dominant (AD) inheritance has also been reported. We reviewed the literature on AD PXE and we studied in detail, both clinically and by DNA studies, a selection of potentially AD pedigrees from our patient population consisting of 59 probands and their family members. Individuals were considered to have definite PXE if they had two of the following three criteria: characteristic ophthalmologic signs, characteristic dermatologic signs, and a positive skin biopsy. In the literature we found only three families with definite PXE in two successive generations and no families with definite PXE in three or more generations. Our own data set comprised three putative AD families. Extensive DNA studies revealed a mutation in only one ABCC6 allele in the patients of these families. Only one of our families showed definite PXE in two generations. Linkage studies revealed that pseudodominance was unlikely in this family. In the other two families AD PXE could not be confirmed after extensive clinical examinations and application of our criteria, since definite PXE was not present in two or more generations. Conclusion: the inheritance pattern in PXE usually is AR. Part of the phenotype in family members of PXE patients might be due to expression in heterozygous carriers of an AR disease. AD inheritance in PXE may exist, but is both after careful literature study and in our patient material much rarer than previously thought. © 2003 Wiley‐Liss, Inc.
Cerebellum—small brain but large confusion: A review of selected cerebellar malformations and disruptions
Authors: Boltshauser Eugen 
Published: April 2004

AbstractDefining and classifying congenital disorders of the cerebellum can be difficult and confusing. One reason is that some abnormalities called “malformations” are not truly (primary) developmental malformations. This applies to Chiari I “malformations” as well as to Chiari II “malformations.” The latter results mainly from a prenatal cerebrospinal fluid (CSF) leak. Also disruptive cerebellar lesions are not uncommon, examples being the “vanishing cerebellum” in myelomeningocele, cerebellar lesions in very low birth weight prematurely born infants, unilateral cerebellar hypoplasia/aplasia, and probably some instances of cerebellar agenesis (CA). The cerebellar hypoplasias consist of a heterogeneous group of inherited and prenatally acquired conditions. The concept of pontocerebellar hypoplasias will need to be expanded beyond the two main types (PCH‐1 and PCH‐2), and demonstrate that a classification system of cerebellar malformations cannot be based on neuroimaging criteria only. Additional studies are expected to show that this also applies to the molar tooth sign, which was initially described in Joubert syndrome (JS). The JS is the prototype of midhindbrain malformation, but its delineation is still unsolved. JS may well be an overdiagnosed entity; many cases likely not having JS are on record. Rhombencephalosynapsis (RS) has been increasingly diagnosed with the advent of neuroimaging. No familial cases have been observed. Although many affected individuals have variable impairments, RS can be found in children with normal cognitive function. In this review, some of the cerebellar anomalies are briefly discussed. © 2004 Wiley‐Liss, Inc.
Cost of fetal alcohol spectrum disorders
Authors: Lupton Chuck , Burd Larry , Harwood Rick 
Published: April 2004

AbstractFetal alcohol syndrome (FAS) is a common identifiable teratogenic cause of mental retardation, neurological deficit, mental disorders, and developmental disabilities. Accurate estimates of the cost of care for persons with FAS are essential for appropriate funding of health care, developmental disabilities services, special education, and other service systems, as well as prioritizing funding of public health prevention efforts. The cost of care for individuals with FAS can be conceptualized as the annual cost of care for one person or a population, or as the lifetime cost of care for an individual. Annual cost estimates for the United States range from $75 million in 1984 to $4.0 billion in 1998. Estimates of lifetime cost vary from $596,000 in 1980 to $1.4 million in 1988. After adjustments for changes in inflation and population, 2002 estimates of total annual cost and lifetime cost are higher. FAS is increasingly being recognized as a large public health problem with high potential for the prevention of future cases and for the prevention of excess disability and premature mortality in persons who are affected. Each day, from 6–22 infants with FAS are born in the United States, and as many as 87–103 more are born with other impairments resulting from prenatal alcohol exposure. Updated and improved cost data on FAS should be a research priority. © 2004 Wiley‐Liss, Inc.
Axonal protection using flecainide in experimental autoimmune encephalomyelitis
Authors: Bechtold David A. , Kapoor Raju , Smith Kenneth J. 
Published: April 2004

AbstractAxonal degeneration is a major cause of permanent neurological deficit in multiple sclerosis (MS), but no current therapies for the disease are known to be effective at axonal protection. Here, we examine the ability of a sodium channel–blocking agent, flecainide, to reduce axonal degeneration in an experimental model of MS, chronic relapsing experimental autoimmune encephalomyelitis (CR‐EAE). Rats with CR‐EAE were treated with flecainide or vehicle from either 3 days before or 7 days after inoculation (dpi) until termination of the experiment at 28 to 30 dpi. Morphometric examination of neurofilament‐labeled axons in the spinal cord of CR‐EAE animals showed that both flecainide treatment regimens resulted in significantly higher numbers of axons surviving the disease (83 and 98% of normal) compared with controls (62% of normal). These findings indicate that flecainide and similar agents may provide a novel therapy aimed at axonal protection in MS and other neuroinflammatory disorders.
Cu2+ toxicity inhibition of mitochondrial dehydrogenases in vitro and in vivo
Authors: Sheline Christian T. , Choi Dennis W. 
Published: April 2004

AbstractWilson's disease results from mutations in the P‐type Cu2+‐ATPase causing Cu2+ toxicity. We previously demonstrated that exposure of mixed neuronal/glial cultures to 20μM Cu2+ induced ATP loss and death that were attenuated by mitochondrial substrates, activators, and cofactors. Here, we show differential cellular sensitivity to Cu2+ that was equalized to 5 μM in the presence of the copper exchanger/ionophore, disulfiram. Because Cu2+ facilitates formation of oxygen radicals (ROS) which inhibit pyruvate dehydrogenase (PDH) and alpha‐ketoglutarate dehydrogenase (KGDH), we hypothesized that their inhibition contributed to Cu2+‐induced death. Toxic CU2+ exposure was accompanied by early inhibition of neuronal and hepatocellular PDH and KGDH activities, followed by reduced mitochondrial transmembrane potential, ΔΨM. Thiamine (1–6mM), and dihydrolipoic acid (LA, 50μM), required cofactors for PDH and KGDH, attenuated this enzymatic inhibition and subsequent death in all cell types. Furthermore, liver PDH and KGDH activities were reduced in the Atp7b mouse model of Wilson's disease prior to liver damage, and were partially restored by oral thiamine supplementation. These data support our hypothesis that Cu2+‐induced ROS may inhibit PDH and KGDH resulting in neuronal and hepatocellular death. Therefore, thiamine or lipoic acid may constitute potential therapeutic agents for Wilson's disease.
Magnetic resonance imaging of labeled T‐cells in a mouse model of multiple sclerosis
Authors: Anderson Stasia A. , Shukaliak‐Quandt Jacqueline , Jordan Elaine K. , Arbab Ali S. , Martin Roland , McFarland Henry , Frank Joseph A. 
Published: April 2004

AbstractMultiple sclerosis (MS) is a T cell–mediated autoimmune disease with early lesions characterized by mononuclear cellular infiltrate, edema, demyelination, and axonal loss that contribute to the clinical course of the disease. Experimental autoimmune encephalomyelitis (EAE) in the mouse is a valuable model with a similar disease course to relapsing‐remitting MS. The ability to detect the migration of encephalitogenic T cells into the central nervous system in EAE and MS would provide key information on these cells role in the development of lesions observed on magnetic resonance imaging (MRI). T cells were labeled for detection by magnetic resonance imaging using Food and Drug Administration–approved, superparamagnetic iron oxide nanoparticles (Ferumoxides) complexed to poly‐L‐Lysine (FE‐PLL). EAE was induced by adoptive transfer of either labeled or unlabeled T cells. After disease onset, FE‐PLL–labeled T cells were detected in the mouse spinal cord using in vivo and ex vivo cellular MRI. Excellent correlation was seen between MRI‐visible lesions in the spinal cord and histopathology. The results demonstrate that T cells labeled with FE‐PLL can induce EAE disease and can be detected in vivo in the mouse model. The magnetic labeling of cells opens the possibility of monitoring specific cellular phenotypes or pharmacologically or genetically engineered cells by MRI.
Graft copolymerization of acrylamide onto carboxymethylcellulose with the xanthate method
Authors: El‐Hady Bothaina Abd , Ibrahim Maha M. 
Published: April 2004

AbstractAcrylamide was grafted to an xanthate mixture of carboxymethylcellulose with a sodium bisulfate/ammonium persulfate redox initiator system in water, sodium hydroxide, potassium hydroxide, and dioxane at 40, 50, 60, 70, and 80°C during a reaction period of 2 h. The grafted polymer and homopolymer were isolated with diethyl ether from the reaction mixture, dried, and weighed. The grafted polymer was characterized with IR and mass spectrometry methods, and the microscopic morphology was detected with electron scanning microscopy. The graft level percentage distinctly increased with the use of sodium hydroxide, potassium hydroxide, and dioxane over that of a reaction carried out completely in an aqueous medium. Also, the graft level decreased as the reaction temperature increased. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 271–278, 2004
Synthesis and properties of 4‐(ω‐methoxyoligodimethylsiloxanyl)butyl maleate: A new surfmer
Authors: Kohut A. M. , Hevus O. I. , Voronov S. A. 
Published: April 2004

AbstractAnionic reactive maleate with hydrophobic oligosiloxane chain was synthesized to use as a stabilizer in the batch and seeded emulsion polymerization of traditional monomers (acrylates, methacrylates, styrene, etc.). Polymerizable surfactant is obtained in a three‐step synthesis, starting from the anionic polymerization of cyclic siloxanes, followed by the silylation of methanol with the obtained cyclic oligomer, and finishing with the acylation of the linear oligomer by maleic anhydride. The improved technique of the synthesis of 4‐chlorobutoxydimethylchlorosilane, one of the initial substances for obtaining siloxane monomer, was elaborated. The anionic polymerization of octamethylcyclotetrasiloxane using cyclic alkoxysilane was carried out to form siloxane cyclic oligomer for the first time. The chemical structure of the monomer synthesized was confirmed by IR spectroscopy and functional analysis. Critical micelle concentration of the obtained surfactant was measured. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 310–313, 2004
1, 2, 4‐Triazine N‐oxide Derivatives: Studies as Potential Hypoxic Cytotoxins. Part II.
Authors: Cerecetto Hugo , González Mercedes , Onetto Silvia , Saenz Patricia , Ezpeleta Olga , de Ceráin Adela López , Monge Antonio 
Published: April 2004

AbstractNew 1, 2, 4‐Triazine N‐oxide and N, N′‐dioxide derivatives were synthesized in order to obtain compounds as selective hypoxic cell cytotoxins. The starting heterocycles have been prepared using a standard microwave oven in a clean and good‐yielded process. The reactivity of methyl‐1, 2, 4‐triazine N4‐oxide and N1, N4‐dioxide with different electrophilic agents has been studied. The desired products were obtained only when iminium electrophiles were employed. The regioselectivity of this process has been studied by means of experimental and theoretical (at ab initio level) procedures. Theoretically was expected that the most stable intermediates where the benzylic‐like anion from position 5. A fact which agreed with the experimental observed regioselectivity. The new compounds were tested for their cytotoxicity in oxia and hypoxia. Some of them proved to be less active in hypoxic conditions than tirapazamine, 3‐amino‐benzo[1, 2‐e]1, 2, 4‐triazine N1, N4‐dioxide. Derivative 19, 6‐methyl‐5‐[2‐(5‐nitrothienyl)ethenyl)‐1, 2, 4‐triazine N4‐oxide, was the most cytotoxic compound, but it was non‐selective.