bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mitochondrial ROS Metabolism: Modulation by Uncoupling Proteins
Authors: Casteilla L. , Rigoulet M. , Pénicaud L. 
Published: August 2002

AbstractMost of the oxygen consumed by aerobic organisms is reduced to water by the enzyme cytochrome c oxidase in the terminal reaction of the mitochondrial respiratory chain. A significant proportion of the oxygen molecules are converted to superoxide anion radicals by complexes I and III via a nonenzymatic process. A cascade of enzymes, some of them inside the mitochondria themselves, scavenges superoxide anions in order to protect cells from oxidative damage induced by reactive oxygen species (ROS). Unfortunately, the quantification of the fluxes of mitochondrial ROS inside living cells is currently almost impossible, and this in turn limits our knowledge. Presently, the involvement of mitochondrial ROS can only be demonstrated by indirect strategies and among them knockout techniques are the most convincing. The yield of superoxide generation and subsequently ROS production depend mostly on oxygen concentration but can be efficiently modulated by mitochondrial uncoupling. This role could be assumed in part by one of the Uncoupling Proteins (UCPs). These proteins have coenzyme Q as an obligatory partner and we present here the hypothesis of UCPs as a crucial element of the respiratory chain. ROS have been mostly involved in degenerative processes including ageing. More recently, numerous studies point out the role of ROS as true intracellular second messengers. A putative role of mitochondrial ROS as the sensing element of energy metabolism is discussed here. We propose that UCPs could play a central role in modulation of ROS‐dependent signalling pathways and metabolic sensing via the modulation of ROS generation.
Mitochondrial Calcium Homeostasis: Mechanisms and Molecules
Authors: Vandecasteele Grégoire , Szabadkai György , Rizzuto Rosario 
Published: August 2002

AbstractDespite the early characterisation of Ca 2+ fluxes in isolated mitochondria and the ability of this ion to up‐regulate dehydrogenases of the Krebs cycle, the low affinity of the organelle uptake pathways was a long‐standing obstacle to the recognition of a physiological role for mitochondrial Ca 2+ uptake. This review begins with a historical account of the main results that proved the contrary and provides a brief description of mitochondrial Ca 2+ signals. Then, it discusses the characteristics of Ca 2+ regulation of mitochondrial function. Finally, it summarizes recent discoveries on structural aspects of mitochondrial reticulum and its connections to signalling partners such as the endoplasmic reticulum or the plasma membrane.
Redox Regulation by Thioredoxin and Thioredoxin‐Binding Proteins
Authors: Nishiyama Akira , Masutani Hiroshi , Nakamura Hajime , Nishinaka Yumiko , Yodoi Junji 
Published: August 2002

AbstractRecent works have shown the importance of reduction/oxidation (redox) regulation in various biological phenomena. Thioredoxin is a 12‐kDa protein with redox‐active dithiol in the active site ‐Cys‐Gly‐Pro‐Cys‐ and constitutes a major thiol reducing system, the thioredoxin system. Thioredoxin plays multiple roles in cellular processes such as proliferation or apoptosis. It also promotes DNA binding of transcription factors such as NF‐ κB, AP‐1, p53, and PEBP2. Overexpression of thioredoxin suppresses the degradation of I κB and the transactivation of NF‐ κB, whereas overexpression of nuclear‐targeted thioredoxin exhibits the enhancement of NF‐ κB‐dependent transactivation. ASK1, a MAP kinase kinase kinase mediating the TNF‐ α signal has been identified as a thioredoxin binding protein. Thioredoxin shows an inhibitory effect on the TNF‐ α induced activation of ASK1 and p38 MAP kinase pathway. We identified p40phox as the thioredoxin binding protein‐1 (TBP‐1) and vitamin D3 up‐regulated protein 1 (VDUP1) as the thioredoxin binding protein‐2 (TBP‐2) by yeast two‐hybrid system. TBP‐2/VDUP1 negatively regulates the expre and reducing activity of thioredoxin. Thioredoxin interacting proteins may be involved in thioredoxin‐mediating regulation.
Ground-Based Testing of Replacement Thermal Control Materials for the Hubble Space Telescope
Authors: Townsend Jacqueline A , Hansen Patricia A , McClendon Mark W , de Groh Kim K , Banks Bruce A 
Published: August 2002

The mechanical and optical properties of the metallized Teflon® FEP thermal control materials on the Hubble Space Telescope (HST) have degraded over the nearly seven years the telescope has been in orbit. Given the damage to the outer layer of the multilayer insulation (MLI) blanket that was apparent during the second servicing mission (SM2), the decision was made to replace the outer layer during subsequent servicing missions. A Failure Review Board was established to investigate the damage to the MLI and identify a replacement material. The replacement material had to meet the stringent thermal requirements of the spacecraft and maintain mechanical integrity for at least ten years. Ten candidate materials were selected and exposed to ten-year HST-equivalent doses of simulated orbital environments. Samples of the candidates were exposed sequentially to lowand high-energy electrons and protons, atomic oxygen, x-ray radiation, ultraviolet radiation and thermal cycling. Following the exposures, the mechanical integrity and optical properties of the candidates were investigated using optical microscopy, scanning electron microscopy (SEM), a laboratory portable spectroreflectometer (LPSR) and a Lambda 9 spectroreflectometer. Based on the results of these simulations and analyses, the Failure Review Board selected a replacement material and two alternatives that showed the highest likelihood of providing the requisite thermal properties and surviving for ten years in orbit.
Important Factors Controlling Synthesis of Imides in Water
Authors: Dao Buu , Hodgkin Jonathan , Morton Trevor C 
Published: August 2002

Four amine/anhydride models have been studied in order to understand the critical factors which control the synthesis of imides and polyimides in water. This synthesis method has been proposed recently as a convenient, environmentally friendly method of producing both thermosetting and thermoplastic polyimides. The key starting step in the synthesis is the formation of a salt/complex between the hydrolysed anhydride and the amine. The results from a combination of quantitative 1H NMR, HPLC and DSC analysis have shown that the reactions are reversible, and that the important factor in driving the reaction to completion in water is the insolubility of the imide product. Analysis of the precipitated imides shows them to be free of significant amounts of the considerably more water soluble amic acids (i.e. the uncyclized amide acids), which often contaminate imides made in conventional aprotic solvents. Of the models investigated, only the imidization of the second amino group in 2, 4, 6-trimethyl-1, 3-phenylene diamine (TMPDA) was subject to kinetic control. A general conclusion from these experiments is that where a different result is observed in water synthesis of imides compared with conventional aprotic solvent synthesis, it is likely to reflect the vastly different solvation powers of the two solvents rather than a difference in reaction mechanism.
New Thermostable Systems: 2. Structure/Properties Relationship of Nadimide-Terminated Fluorinated Polyimides
Authors: Loustalot Marie Florence Grenier , Billon Laurent , Sillion Bernard 
Published: August 2002

The thermomechanical properties of 12 nadimide endcapped oligomers synthesized by polycondensation of nadic anhydride (NA), hexafluoroisopropylidene-2, 2′-diphthalic acid anhydride (HFDA) and phenylene diamines, meta ( mPDA), para ( pPDA) or 9, 9-bis(4-aminophenyl)fluorene (cardo diamine) have been studied. The rheological curves obtained showed the presence of two relaxations: α, associated with the glass transition temperature, and β, due to local molecular movements with the glass transition. The temperature of the loss modulus G″ associated with these two relaxations varied in the domain of molecular weight M n according to a Fox-Flory relation. By studying the relationship between chemical structures and mechanical properties, the influence of endo/exo isomerization of the nadimide end groups on the glass transition temperature T g has been demonstrated. For a given oligomer, the T g value increases with increasing percentage of exo isomers. The thermo-oxidative stability of the HFDA, PDA and NA oligomers increases when the molecular weight increases.
Aromatic Polyimides Containing p-Quarterphenyl and p-Sexiphenyl Units
Authors: Morikawa Atsushi , Ono Katsumichi 
Published: August 2002

We have prepared aromatic polyimides PI-Ar- m containing p-quarterphenyl ( m = 2) and p-sexiphenyl ( m = 4) units. [ILLEGIBLE] These polyimides are characterized by having long phenylene units and the introduction of these has a strong influence on the properties of polyimides. In this paper, the properties of polyimides are compared with those of polyimides from 3,3″,4,4″- p-terphenyltetracarboxylic dianhydride ( m = 1) and 3,3′,4,4′-biphenyltetracarboxylic dianhydride ( m = 0), which had been previously prepared, and discussed on the basis of the number ( m) of phenylene units in the dianhydrides.
Study of the polymerization of high-performance polymers by electrons and x-rays: 1. The case of polypropargylic-butanedioldimethacrylate systems
Authors: Grenier-Loustalot Marie-Florence , Denizot Vincent , Beziers Daniel 
Published: August 2002

We have investigated the polymerization of polypropargylic butanedioldimeth-acrylate derivatives using electron and x-ray irradiation. The results obtained with the pure resin and carbon-fibre-based composites were compared in terms of kinetics, mechanisms and properties with those obtained by thermal polymerization. Data gathered using a panoply of solid state physicochemical techniques have shown that these polymers are good systems for obtaining composites having high thermal stability at temperatures higher than 350°C.
Impacts of six genetic modifications of corn on feed cost and consumption of traditional feed ingredients
Authors: Yu Tun‐Hsiang , Baumel C. Phillip , Hardy Connie L. , McVey Marty J. , Johnson Lawrence A. , Sell Jerry L. 
Published: August 2002

AbstractThis study evaluates the impact of six genetically modified corns on swine and poultry feed costs and on the use of traditional feed ingredients. A Brill linear programming model was used to calculate least‐cost feed rations for broilers, layers, tom turkeys, 8–13 pound pigs and finisher hogs. This analysis indicates that likely price reductions in traditional feed ingredients will drive most of the current genetic modifications of corn out of the feed markets. Alternative methods of making genetically modified corns more competitive in the marketplace include stacking modifications to increase the gross value per bushel and lowering the costs of modified corn by reducing yield drag and seed costs. [EconLit Classification: Q17] &copy; 2002 Wiley Periodicals, Inc.
Borrowing constraints and the agricultural investment decision process
Authors: Gutierrez Luciano 
Published: August 2002

AbstractThis paper develops a dynamic intertemporal model under the hypothesis of asymmetric information for the analysis of the rate of investment in the agricultural sector. The model stresses the importance of borrowing constraints for the investment decision of firms. Using the model we derive, following Abel and Blanchard's (1986) approach, an estimate for marginal Tobin's Q. We find that this series is positively and strongly related to the agricultural rate of investment in Italy during the period of 1960–1996. [Econ‐Lit Citations: Q14, E62, E22] © 2002 Wiley Periodicals, Inc.
Progressive multifocal leukoencephalopathy after fludarabine therapy for low‐grade lymphoproliferative disease
Authors: Vidarsson Brynjar , Mosher Deane F. , Salamat M. Shahriar , Isaksson Helgi J. , Onundarson Pall T. 
Published: August 2002

AbstractFludarabine is becoming the initial therapy for low‐grade lymphoproliferative malignancies, such as CLL and follicular lymphoma. Fludarabine is highly immunosuppressive in addition to being myelosuppressive and has been associated with neurotoxicity. Progressive multifocal leukoencephalopathy (PML) is an infection with JC virus of the white matter of the central nervous system seen mostly in immunosuppressed patients. We describe two patients treated with fludarabine who developed PML. Immunolabeling was positive for JCV in both patients, but PCR was repeatedly negative in one of them. We suggest that fludarabine may increase the risk of PML in patients with lymphoproliferative diseases. Am. J. Hematol. 70:51–54, 2002. © 2002 Wiley‐Liss, Inc.
Hematologic masquerade of rhabdomyosarcoma
Authors: Sandberg Avery A. , Stone John F. , Czarnecki Lawrence , Cohen Jesse D. 
Published: August 2002

AbstractWe present the case of a 12‐year‐old boy admitted with the diagnosis of acute leukemia, but found to have an infiltration of the marrow by an alveolar rhabdomyosarcoma (RMS) as determined by the cytogenetic demonstration of a t(2;13)(q25;q14). A primary tumor could not be found. With this case as a basis, we have tabulated features of all similar cases in the literature and discuss the possible optimal approaches to establishing the correct diagnosis in such patients. Am. J. Hematol. 68:51–57, 2001. © 2001 Wiley‐Liss, Inc.
Association of polymorphisms of the estrogen receptor gene with anxiety‐related traits in children and adolescents: A longitudinal study
Authors: Prichard Zoë , Jorm Anthony F. , Prior Margot , Sanson Ann , Smart Diana , Zhang Yafei , Huttley Gavin , Easteal Simon 
Published: August 2002

AbstractAnxiety problems and associated temperamental traits are multifactorial, determined by the interaction of genetic and environmental factors. Genetic effects may involve both neurotransmitters and hormones. A good candidate gene for association with anxiety‐related traits is the estrogen receptor (ESRα). Estrogen exerts an effect on mood and behavior in humans through gene regulation on binding to estrogen receptor protein. Association between ESRα polymorphism and anxiety‐related traits was investigated in a cohort of 680 Australian adolescents studied from 4–8 months to 15–16 years of age. Genotype frequencies were estimated for polymorphic PvuII and XbaI restriction sites in intron 1 and a microsatellite [(TA)n] locus 5′ of ESRα. There was strong linkage disequilibrium between the three loci and a significant sex difference was observed in allele (for (TA)n, PvuII) and genotype (for XbaI) frequencies. There were no significant allelic or genotypic differences in anxiety‐related traits for the three loci tested. However, some significant associations were found for PvuII/(TA)n and XbaI/(TA)n two‐locus genotypes and anxiety, accounting for between 1.6% and 2.8% of the total variance for anxiety in this population. The discordance in Hardy‐Weinberg proportions at the XbaI locus between the sexes is an important finding, perhaps indicating a sex‐specific role for ESRα in fetal survival. © 2001 Wiley‐Liss, Inc.
Ring chromosome 6 in three fetuses: Case reports, literature review, and implications for prenatal diagnosis
Authors: Urban Maik , Bommer Christiane , Tennstedt Cornelia , Lehmann Katarina , Thiel Gundula , Wegner Rolf‐Dieter , Bollmann Rainer , Becker Rolf , Schulzke Ines , Körner Hannelore 
Published: August 2002

AbstractPrenatal and postnatal findings in three fetuses with a ring chromosome 6 are presented, and the literature of this rare cytogenetic disorder is reviewed. The described fetuses illustrate the broad spectrum of the clinical manifestation of ring chromosome 6. In one fetus, the disorder was diagnosed incidentally by a routine amniocentesis due to advanced maternal age. The other two fetuses were hydrocephalic and had other congenital anomalies. Remarkably, the ring chromosome 6 tends to disappear in cultured amniotic fluid cells; karyotyping revealed complete or nearly complete monosomy 6. In contrast, the ring was preserved in high proportions of fetal leukocytes. Postnatal growth retardation is the only consistent finding of this chromosomal disorder. Maternal age is not significantly above average. An additional review of 20 literature cases revealed a striking tendency to hydrocephalus, either due to deficient brain growth or secondary to an aqueductal stenosis. Children with hydrocephalus and ring chromosme 6 tend to display facial dysmorphism and may have additional malformations, growth failure, eye anomalies, and seizures. In contrast, there are two reports on children with a ring chromosome 6 who had short stature, normal appearance, and a normal or almost‐normal psychomotor development. In such patients at the mild end of the clinical spectrum, the phenotype is basically restricted to what Kosztolányi. [1987: Hum Genet 75:174–179] delineated as “ring syndrome,” comprising “severe growth failure without major malformations, without a specific deletion syndrome, with only a few or no minor anomalies, and mild to moderate mental retardation.” This “ring syndrome” is considered to occur independently of the autosome involved in the ring formation. The overall impression from our cases and from the literature review of cases with ring chromosome 6 is that the karyotype‐genotype correlation is poor. This makes prognostic counseling of parents difficult and unsatisfactory. Serial targeted ultrasound examinations, especially of the brain, are decisive factors in elucidating the prognosis. © 2002 Wiley‐Liss, Inc.
High risk of malignancy in mosaic variegated aneuploidy syndrome
Authors: Jacquemont Sébastien , Bocéno Michelle , Rival Jean Marie , Méchinaud Françoise , David Albert 
Published: August 2002

AbstractFourteen cases of mosaic variegated aneuploidy (MVA) syndrome have been reported in the last 10 years. The phenotype of this rare condition has been quite consistent: severe microcephaly, growth deficiency, mild physical anomalies, and mental retardation. We describe here a young boy in whom MVA syndrome is associated to myelodysplasia with a monosomy 7 bone marrow clone. At the age of 3 years, myelodysplasia progressed to an acute lymphoblastic leukemia, and the patient died soon after. Several syndromes with short stature and severe microcephaly, such as the Seckel and Nijmegen syndromes, comprise hematological findings and chromosome instability. However, chromosome instability was not comfirmed in our patient. MVA with hematological findings has not been reported before, but 3 patients of 14 (21%) have developed a malignancy (rhabdomyosarcoma, acute lymphoblastic leukemia, and nephroblastoma). Therefore, we propose that MVA is a condition predisposing to neoplasia. © 2002 Wiley‐Liss, Inc.
Association study of MAO‐A, COMT, 5‐HT2A, DRD2, and DRD4 polymorphisms with illness time course in mood disorders
Authors: Cusin Cristina , Serretti Alessandro , Lattuada Enrico , Lilli Roberta , Lorenzi Cristina , Smeraldi Enrico 
Published: August 2002

AbstractThe aim of our study was to investigate a possible influence of monoamine oxydase A (MAO‐A), catechol‐O‐methyltransferase (COMT), serotonin receptor 2A (5‐HT2A), dopamine receptor D2 (DRD2), and dopamine receptor D4 (DRD4) gene variants on timing of recurrence in mood disorders. Gene variants were determined using PCR‐based techniques in 550 inpatients affected by recurrent mood disorders (major depressives: n = 212; bipolars: n = 338), rapid cycling mood disorder (n = 81), and 663 controls. We investigated possible genetic influences by comparing illness time course of subjects subdivided according to genotype using multivariate analysis of variance (MANOVA). We could not observe a significantly different time course. No demographic and clinical variables such as sex, age or polarity of onset, presence of psychotic features, genetic loading, or education level influenced the observed results. Our results suggest that MAO‐A, COMT, 5‐HT2A, DRD2, and DRD4 gene variants are not involved in susceptibility toward different time courses in mood disorders. © 2002 Wiley‐Liss, Inc.
Arsenic pollution of groundwater in Bangladesh
Authors: Tanabe Kimiko , Yokota Hiroshi , Hironaka Hiromi , Tsushima Sachie , Kubota Yoshihiro 
Published: August 2002

AbstractArsenic concentrations in groundwater around the village of Samta, Jessore District, Bangladesh were measured. Distribution patterns of arsenic in groundwater were determined. Arsenic concentrations in drinking water tubewells mostly exceeded WHO guidelines. Copyright © 2001 John Wiley & Sons, Ltd.
Crystallization and crosslinking of polyamide‐1010 under elevated pressure
Authors: Yang Jun , Dong Wenfei , Luan Yucheng , Liu Jingjiang , Liu Shue , Guo Xingyuan , Zhao Xudong , Su Wenhui 
Published: August 2002

AbstractThe structure and thermal properties of polyamide‐1010 (PA1010), treated at 250°C for 30 min under pressures of 0.7–2.5 GPa, were studied with wide‐angle X‐ray diffraction (WAXD), infrared (IR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Crystals were formed when the pressures were less than 1.0 GPa or greater than 1.2 GPa. With increasing pressure, the intensity of the diffraction peak at approximately 24° was enhanced, whereas the peak at approximately 20° was depressed. The triclinic crystal structure of PA1010 was preserved. The highest melting temperature of the crystals obtained in this work was 208°C for PA1010 treated at 1.5 GPa. Crosslinking occurred under pressures of 1.0–1.2 GPa. Only a broad diffraction peak centered at approximately 20° was observed on WAXD patterns, and no melting and crystallization peaks were found on DSC curves. IR spectra of crosslinked PA1010 showed a remarkable absorption band at 1370 cm−1. The NH stretching vibration band at 3305 cm−1 was weakened. Crystallized PA1010 had a higher thermal stability than crosslinked PA1010, as indicated on TGA curves by a higher onset temperature of decomposition. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2522–2527, 2002
Porous properties of poly(glycidyl methacrylate‐co‐trimethylolpropane trimethacrylate) resins synthesized by suspension polymerization
Authors: Qi Tao , Sonoda Akinari , Makita Yoji , Kanoh Hirofumi , Ooi Kenta , Hirotsu Takahiro 
Published: August 2002

AbstractPorous copolymer beads of 2,3‐epoxypropyl methacrylate (glycidyl methacrylate, GMA) crosslinked with 2‐ethyl‐2‐(hydroxymethyl)‐propan‐1,3‐diol trimethacrylate (trimethylolpropane trimethacrylate, TRIM) were prepared with toluene and octan‐2‐one as porogens by suspension polymerization. With an increase in the ratio of porogen to monomer, the total pore volume of poly(GMA‐co‐TRIM) increases significantly, whereas the surface area hardly changes. The total pore volume also depends on the nature of the porogen, exhibiting a maximum at the larger GMA contents in the monomer mixture of 50% v/v with octan‐2‐one and of 60% v/v with toluene, compared to that at the GMA content of 25% v/v with a 9/1 v/v mixture of cyclohexanol and dodecan‐1‐ol [Verweij, P. D.; Sherrington, D. C. J Mater Chem 1991, 1 (3), 371]. The surface area decreases significantly with an increase in the ratio of GMA to TRIM, almost regardless of the nature of the porogen. The porous properties of poly(GMA‐co‐TRIM) was well explained on the basis of phase separation, particularly taking into account not only the solubility parameters of the resulting polymer network and porogen but also the rigidity of TRIM. The porous poly(GMA‐co‐TRIM) may be a promising polymer matrix of novel materials for separation of boron isotopes. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2374–2381, 2002