bluuebunny/crossref_metadata_2025_split huggingface dataset:
POLG mutations associated with Alpers' syndrome and mitochondrial DNA depletion
Authors: Naviaux Robert K. , Nguyen Khue V. 
Published: March 2004

AbstractAlpers' syndrome is a fatal neurogenetic disorder first described more than 70 years ago. It is an autosomal recessive, developmental mitochondrial DNA depletion disorder characterized by deficiency in mitochondrial DNA polymerase γ (POLG) catalytic activity, refractory seizures, neurodegeneration, and liver disease. In two unrelated pedigrees of Alpers' syndrome, each affected child was found to carry a homozygous mutation in exon 17 of the POLG locus that led to a Glu873Stop mutation just upstream of the polymerase domain of the protein. In addition, each affected child was heterozygous for the G1681A mutation in exon 7 that led to an Ala467Thr substitution in POLG, within the linker region of the protein. Ann Neurol 2004
8‐Oxabicyclo[3.2.1]oct‐6‐en‐3‐one: Anwendungen in der asymmetrischen Synthese polyoxygenierter Bausteine
Authors: Hartung Ingo V. , Hoffmann H. Martin R. 
Published: March 2004

AbstractDie Entdeckung und das Design von zuverlässigen und effizienten Methoden zum Aufbau chiraler Bausteine spielt in der modernen Naturstoffsynthese eine entscheidende Rolle. 8‐Oxabicyclo[3.2.1]oct‐6‐en‐3‐one sind leicht zugängliche Gerüste mit definierten stereochemischen Eigenschaften, die in Nicht‐Aldolansätzen zur Herstellung chiraler Bausteine genutzt werden. Strategien zu ihrer enantioselektiven Synthese umfassen Methoden für asymmetrische Cycloadditionen, Desymmetrisierungsprotokolle und “Racemic‐Switch‐Operationen”. Die Ergebnisse dieser Arbeiten werden in diesem Aufsatz präsentiert und eingeschätzt.
Using N‐grams for Arabic text searching
Authors: Mustafa Suleiman H. , Al‐Radaideh Qasem A. 
Published: March 2004

AbstractN‐grams have been widely investigated for a number of text processing and retrieval applications. This article examines the performance of the digram and trigram term conflation techniques in the context of Arabic free text retrieval. It reports the results of using the N‐gram approach for a corpus of thousands of distinct textual words drawn from a number of sources representing various disciplines. The results indicate that the digram method offers a better performance than trigram with respect to conflation precision and conflation recall ratios. In either case, the N‐gram approach does not appear to provide an efficient conflation approach due to the peculiarities imposed by the Arabic infix structure that reduces the rate of correct N‐gram matching.
Novel Methodologies for the Synthesis of Cyclic Carbonates
Authors: Yoshida Masahiro , Ihara Masataka 
Published: March 2004

AbstractCyclic carbonates are valuable compounds that have applications in a variety of chemical fields. Methodologies for the synthesis of cyclic carbonates are well investigated in recent years, and the most successful and popular procedure is the utilization of CO2. This paper presents recent progress in the synthesis of cyclic carbonates by a CO2‐fixation process, which involves novel palladium‐catalyzed CO2‐recycling reactions.
A Catalytic Antibody against a Tocopherol Cyclase Inhibitor
Authors: Manetsch Roman , Zheng Lei , Reymond Martine T. , Woggon Wolf‐Dietrich , Reymond Jean‐Louis 
Published: March 2004

AbstractThe cyclic ammonium cation 5 and its guanidinium analogue 4 are inhibitors of tocopherol cyclase. Monoclonal antibodies were raised against protein conjugates of the haptens 1–3 and screened for catalytic reactions with alkene 8, a short chain analogue of the natural substrate phytyl‐hydroquinone 6, and its enol ether analogues 10 a, b. Antibody 16E7 raised against hapten 3 was found to catalyze the hydrolysis of Z enol ether 10 a to form hemiacetal 12 with an apparent rate acceleration of kcat/kuncat=1400. Antibody 16E7 also catalyzed the elimination of Kemp's benzisoxazole 59. The absence of cyclization in the reaction of enol ether 10 a was attributed to the competition of water molecules for the oxocarbonium cation intermediate within the antibody binding pocket. Hapten and reaction design features contributing to this outcome are discussed. Antibody 16E7 provides the first example of a carboxyl group acting both as an acid in an intrinsically acid‐catalyzed process and as a base in an intrinsically base‐catalyzed process, as expected from first principles. In contrast to the many examples of general‐acid‐catalyzed processes known to be catalyzed by catalytic antibodies, the specific‐acid‐catalyzed cyclization of phytyl‐hydroquinone 6 or its analogue 8 still eludes antibody catalysis.
A General Study of [(η5‐Cp′)2Ti(η2‐Me3SiC2SiMe3)]‐Catalyzed Hydroamination of Terminal Alkynes: Regioselective Formation of Markovnikov and Anti‐Markovnikov Products and Mechanistic Explanation (Cp′=C5H5, C5H4Et, C5Me5)
Authors: Tillack Annegret , Jiao Haijun , Garcia Castro Ivette , Hartung Christian G. , Beller Matthias 
Published: March 2004

AbstractA general study of the regioselective hydroamination of terminal alkynes in the presence of [(η5‐Cp)2Ti(η2‐Me3SiC2SiMe3)] (1), [(η5‐CpEt)2Ti(η2‐Me3SiC2SiMe3)] (CpEt=ethylcyclopentadienyl) (2), and [(η5‐Cp*)2Ti(η2‐Me3SiC2SiMe3)] (Cp*=pentamethylcyclopentadienyl) (3) is presented. While aliphatic amines give mainly the anti‐Markovnikov products, anilines and aryl hydrazines yield the Markovnikov isomer as main products. Interestingly, using aliphatic amines such as n‐butylamine and benzylamine the different catalysts lead to a significant change in the observed regioselectivity. Here, for the first time a highly selective switch from the Markovnikov to the anti‐Markovnikov product is observed simply by changing the catalyst. Detailed theoretical calculations for the reaction of propyne with different substituted anilines and tert‐butylamine in the presence of [(η5‐C5H5)Ti(NR)(NHR)] (R=4‐C6H4X; X=H, F, Cl, CH3, 2,6‐dimethylphenyl) reveal that the experimentally observed regioselectivity is determined by the relative stability of the corresponding π‐complexes 10. While electrostatic stabilization favors the Markovnikov performance for aniline, the steric repulsive destabilization disfavors the Markovnikov performance for tert‐butylamine.
Parvalbumin‐containing interneurons in the basolateral amygdala express high levels of the α1 subunit of the GABAA receptor
Authors: McDonald Alexander Joseph , Mascagni Franco 
Published: March 2004

AbstractThe basolateral amygdala (ABL) is essential for the amnestic effects of benzodiazepines in aversive learning tasks. Because the α1 subunit of the γ‐aminobutyric acid (GABA)A receptor is critical for these amnestic actions, knowledge of the neuronal localization of this subunit in the ABL should contribute to an understanding of the candidate neuronal mechanisms involved. To examine this question, we used dual‐labeling immunohistochemical techniques to study the localization of the α1 subunit in the ABL. Our results suggest that the α1 subunit of the GABAA receptor is localized primarily in GABAergic interneurons in the ABL at the somal level, although the intense neuropil staining in the lateral nucleus suggests that distal dendrites of pyramidal projection neurons in this nucleus may also contain high levels of the α1 subunit. The great majority of α1‐immunoreactive interneurons also exhibit immunoreactivity for the β2/3 subunits of the GABAA receptor. Parvalbumin‐positive (PV+) interneurons are the main interneuronal subpopulation exhibiting α1 immunoreactivity, but some calretinin‐positive interneurons also express this subunit. These data suggest that certain subpopulations of GABAergic interneurons in the ABL, especially PV+ cells, receive a robust GABAergic innervation. Because the most likely source of this innervation is intrinsic, these results suggest that PV+ interneurons could constitute an important component of interneuronal networks in the ABL. These networks may be critical for the generation of synchronized rhythmic oscillations involved in consolidation of emotional memories. The activation of α1‐containing GABAA receptors in the ABL by benzodiazepines may disrupt rhythmic oscillations critical for memory consolidation. J. Comp. Neurol. 473:137–146, 2004. © 2004 Wiley‐Liss, Inc.
Increased citrullinated glial fibrillary acidic protein in secondary progressive multiple sclerosis
Authors: Nicholas Anthony P. , Sambandam Thiagarajan , Echols Joshua D. , Tourtellotte Wallace W. 
Published: March 2004

AbstractIn this study, we demonstrate that grossly unaffected white matter from secondary progressive multiple sclerosis (SP‐MS) patients is heavily citrullinated, as compared to normal white matter from control patients. Citrullination was most pronounced at plaque interfaces and was shown to colocalize with glial fibrillary acidic protein (GFAP)‐immunoreactivity using dual color immunofluorescence. In contrast, the plaques themselves weakly stained for citrullinated proteins compared to control white matter and usually contained a blood vessel with surrounding astrocytes that were positive both for citrullinated proteins and GFAP. In SP‐MS brain samples, but not in normal brains, long fibers of colocalized GFAP‐ and citrullinated proteins extended into the gray matter. Increased numbers of astrocytes containing citrullinated proteins and GFAP were also present at the junction between the gray and white matter in SP‐MS brains. Western blot analysis of acidic brain proteins from nonplaque‐containing white matter showed upregulation of multiple citrullinated GFAP proteins in SP‐MS brains as compared to controls. Our results demonstrate that increased amounts of citrullinated GFAP are present in SP‐MS brains, but also shows that these proteins are present in areas of MS brains that were grossly normal appearing. These data raise the possibility that citrullination of GFAP contributes to the pathophysiology of MS. J. Comp. Neurol. 473:128–136, 2004. © 2004 Wiley‐Liss, Inc.
Quantitative analysis of axon collaterals of single neurons in layer IIa of the piriform cortex of the guinea pig
Authors: Yang Junli , Ul Quraish Afraz , Murakami Kunio , Ishikawa Youichi , Takayanagi Masaaki , Kakuta Sachiko , Kishi Kiyoshi 
Published: March 2004

AbstractTo study the various types of neurons in layer IIa in the piriform cortex (PC) and the spatial distribution of their axons, axon collaterals of three neurons in layer IIa were labeled and quantitatively analyzed by intracellular injection of biocytin in the guinea pig. Individual neurons have highly distributed axon collaterals, which display a little tendency toward patchy concentrations inside as well as outside the PC. One semilunar cell in the posterior PC had 54‐mm‐long axon collaterals and 4,200 boutons, out of which 2,100 (49% of the total number of boutons) were distributed in the PC. One semilunar‐pyramidal transitional cell in the posterior PC had 256‐mm‐long axon collaterals and 23,000 boutons, out of which 16,100 (70% of the total number of boutons) and 4,000 (18% of the total number of boutons) were respectively distributed in all layers and in layer Ia of the PC. One multipolar cell in the posterior PC had 188‐mm‐long axon collaterals and 18,000 boutons, out of which 13,700 (78% of the total number of boutons) were distributed in the PC. Our results revealed that the connection patterns of individual cells in layer IIa have most of the features required for an associative neural network, which may function as a content‐addressable memory for the association of odor stimuli. J. Comp. Neurol. 473:30–42, 2004. © 2004 Wiley‐Liss, Inc.
Pyrazolate‐Based Dinucleating Ligands in L2M2 Scaffolds: Effects of Bulky Substituents and Coligands on Structures and M···H−C Interactions
Authors: Röder Jens C. , Meyer Franc , Kaifer Elisabeth , Pritzkow Hans 
Published: March 2004

AbstractA series of nickel(II) and palladium(II) complexes [L2M2]2+ have been prepared and structurally characterized, where L is a pyrazolate ligand with bulky 2,6‐dimethyl‐ or 2,6‐di(isopropyl)anilinomethyl side arms. Coordinating counter anions such as chloride can bind to axial sites of the dinickel species in a solvent‐dependent process, giving rise to five‐coordinate high‐spin metal ions. In the case of weakly coordinating anions, the metal ions are found in roughly square‐planar environments, and the structures are governed by the tendency of the bulky aryl groups to avoid each other, which forces the methyl or isopropyl substituents in the aryl 2‐ and 6‐positions to approach the metal ions from the axial directions. This leads to drastic low‐field shifts of the respective 1H NMR signals, e.g. δ = 7.86 ppm for the isopropyl −CH which comes in close proximity to the low‐spin nickel(II) center. The relevance of such low‐field NMR resonances of protons close to the axial sites of d8 metal ions for possible three‐center four‐electron M···H−C hydrogen bonds involving the filled d orbital of the metal ion is discussed. In the present case, attractive M···H interactions are assumed to be of no major significance. This was corroborated by the structure of a further [L2Ni2]2+ type complex where the anilinomethyl side arms bear only a single 2‐isopropyl group, which was found rotated away from the metal. Additional spectroscopic and electrochemical properties of the various complexes are reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Spontaneous and mitomycin C‐induced micronuclei in peripheral blood reticulocytes from severely malnourished rats
Authors: Ortiz Rocío , Medina Hilda , Rodríguez Leonor , González‐Márquez Humberto , Cortés Edith 
Published: March 2004

AbstractSevere malnutrition caused by deficiencies in protein, calorie, and micronutrient intake is widely distributed throughout the world and is a particular problem in developing countries. Animal models have been useful for studying the effects of malnutrition under different experimental conditions. In this study, we have evaluated the effect of malnutrition on the frequency of spontaneous and mitomycin C (MMC)‐induced micronuclei in the peripheral blood of rats measured using a flow cytometric analysis technique. Neonatal rats were experimentally malnourished during lactation and assayed at weaning (21 days of age). The malnourished rats weighed 49.2% less than well‐nourished controls and had lower concentrations of serum protein, triglycerides, and cholesterol. In rats not treated with MMC, the frequency of micronucleated reticulocytes (MN‐RETs) was 1.6 times greater in malnourished rats than in well‐nourished rats (0.48% ± 0.16% vs. 0.31% ± 0.09%). The mean MN‐RET frequency measured 32 hr after treatment with single i.p. doses of 0.5, 0.75, or 1.0 mg/kg of MMC was 0.60 ± 0.10 vs. 0.84 ± 0.14, 1.21 ± 0.52 vs. 2.36 ± 0.47, and 2.50 ± 0.06 vs. 4.64 ± 1.14 for well‐nourished vs. malnourished rats, respectively. Statistical comparisons indicate significant differences between the two groups of rats at all doses tested. Malnourishment and MMC treatment had no significant effects on the frequencies of RETs or micronucleated normochromatic erythrocytes. The data indicate that protein‐calorie malnutrition during lactation is associated with increased frequencies of MN‐RETs, which are indicative of chromosome damage. These findings suggest that malnutrition could result in greater susceptibility to environmental damage. Environ. Mol. Mutagen. 43:179–185, 2004. © 2004 Wiley‐Liss, Inc.
Genotoxicity modulation by cadmium treatment: Studies in the Drosophila wing spot test
Authors: Rizki Mostapha , Kossatz Elk , Creus Amadeu , Marcos Ricardo 
Published: March 2004

AbstractThe genotoxic activity of cadmium chloride (CC) has been evaluated in the somatic mutation and recombination test (SMART) in Drosophila melanogaster. In addition, its possible modulating effect on the genotoxicity of two known mutagenic agents, potassium dichromate (PDC) and ethyl methanesulfonate (EMS), was investigated. Three different types of combined treatments of CC with the two genotoxins were performed: pretreatment, cotreatment, and posttreatment. The SMART assay is based on the principle that loss of heterozygosity for the recessive markers, multiple wing hairs (mwh) and flare‐3 (flr3), leads to the formation of mutant clones in the imaginal disks of larvae, which are expressed as mutant spots on the wings of adult flies. Thus, after adult emergence, the wings of the adult flies were scored for the presence of single and/or twin spots. Our results show that CC alone was not effective in increasing the frequency of any of the three categories of spots (small, large, and twin). In the cotreatment experiments, CC increased the genotoxicity of PDC but it decreased the genotoxicity of EMS. No effects of CC were observed in the pretreatment or posttreatment experiments; however, only low concentrations of CC, PDC, and EMS were tested in the pretreatment assays due to the high toxicity of the treatment. Although our results with PDC are consistent with the hypothesis that cadmium can interfere with repair mechanisms, the EMS data suggest that other modulating mechanisms are also involved in the genotoxicity of this metal. Environ. Mol. Mutagen. 43:196–203, 2004. © 2004 Wiley‐Liss, Inc.
Industrial wastewater treatment in a membrane bioreactor: A review
Authors: Marrot B. , Barrios‐Martinez A. , Moulin P. , Roche N. 
Published: March 2004

AbstractThis paper provides a detailed literature review of wastewater treatment in a membrane bioreactor process (MBR) with special focus on industrial wastewater treatment. MBR systems are compared with conventional wastewater treatment systems. The characteristics of the bioreactor treatment process (biomass concentration and floc size, organic and mass loading rates, etc.) are examined. The membrane separation of microorganisms from the treated wastewater is discussed in detail. Problems of membrane fouling and membrane washing and regeneration, linked to activated sludge characteristics, are examined. © 2004 American Institute of Chemical Engineers Environ Prog, 23: 59–68, 2004
Influence of start‐ups with fuel‐oil on the operation of electrostatic precipitators in pulverised coal boilers
Authors: Navarrete B. , Vilches L.F. , Cañadas L. , Salvador L. 
Published: March 2004

AbstractThis article describes the results of a series of tests carried out in a pilot fly ash electrostatic precipitation facility operating with real gases from a 550 MWe pulverized coal‐fired power station. The main goal of these tests was to determine the effect of boiler start‐ups on the performance of the electrostatic precipitator.The tests were carried out during start‐ups of the power station boiler. All tests were carried out with the same fuel. An evaluation was made of the effect of the use of fuel‐oil as auxiliary fuel in start‐ups and shut‐downs of the boiler, and different electrostatic precipitator operation procedures were tested during start‐ups and shut‐downs.The results of the experiments made it possible to assess the relative importance of different variables on the possible deterioration of the efficiency of the precipitator. Also evaluated were operational modes that have demonstrated an improvement in the performance of the precipitators after the transient stage of these operations. As a result of this study, a number of important operational recommendations are made on boiler start‐up and shut‐down procedures. © 2004 American Institute of Chemical Engineers Environ Prog, 23: 29–38, 2004
Computations of two passing‐by high‐speed trains by a relaxation overset‐grid algorithm
Authors: Liu Jenn‐Long 
Published: March 2004

AbstractThis paper presents a relaxation algorithm, which is based on the overset grid technology, an unsteady three‐dimensional Navier–Stokes flow solver, and an inner‐ and outer‐relaxation method, for simulation of the unsteady flows of moving high‐speed trains. The flow solutions on the overlapped grids can be accurately updated by introducing a grid tracking technique and the inner‐ and outer‐relaxation method. To evaluate the capability and solution accuracy of the present algorithm, the computational static pressure distribution of a single stationary TGV high‐speed train inside a long tunnel is investigated numerically, and is compared with the experimental data from low‐speed wind tunnel test. Further, the unsteady flows of two TGV high‐speed trains passing by each other inside a long tunnel and at the tunnel entrance are simulated. A series of time histories of pressure distributions and aerodynamic loads acting on the train and tunnel surfaces are depicted for detailed discussions. Copyright © 2004 John Wiley & Sons, Ltd.
TNF‐α in vivo stimulates apoptosis in fibroblasts through caspase‐8 activation and modulates the expression of pro‐apoptotic genes
Authors: Alikhani Mani , Alikhani Zoubin , Raptis Markos , Graves Dana T. 
Published: March 2004

AbstractApoptosis of matrix producing cells is common among many inflammatory diseases. The goal of the present study was to examine the apoptotic effects of tumor necrosis factor‐α (TNF‐α) on fibroblastic cells in vivo and to investigate the role of different caspases in this process. This was accomplished in vivo by subcutaneous injection of TNF‐α in mice. The direct effects of TNF‐α on fibroblast apoptosis were studied in vitro with normal diploid human fibroblasts. The results indicate that TNF‐α in vivo induces apoptosis of fibroblasts. By RNase protection assay, we demonstrated that TNF‐α stimulates expression of 12 apoptotic genes. Fluorometric studies demonstrated that TNF‐α in vivo predominantly increased caspase‐8 and ‐3 activity and by use of specific inhibitors, the activation of caspase‐3 was shown to be initiated by caspase‐8 with only a minor contribution from caspase‐9. Thus, TNF‐α acts to modulate the expression of many genes that favors apoptosis of fibroblastic cells, which is dependent mostly upon signaling through caspase‐8. © 2004 Wiley‐Liss, Inc.
G protein‐coupled receptor agonist‐stimulated expression of ATF3/LRF‐1 and c‐myc and comitogenic effects in hepatocytes do not require EGF receptor transactivation
Authors: Nilssen Laila S. , Ødegård John , Thoresen G. Hege , Molven Anders , Sandnes Dagny , Christoffersen Thoralf 
Published: March 2004

AbstractSeveral agonists acting on G protein‐coupled receptors (GPCR) enhance the mitogenic effect of epidermal growth factor (EGF) in rat hepatocytes, through mechanisms that have only partially been clarified. Results in various cells have led to the idea that a major mechanism for GPCR‐mediated stimulation of cell growth is transactivation of receptor tyrosine kinases, particularly the EGF receptor (EGFR), leading to rapid phosphorylation of the EGFR and activation of downstream signaling pathways. In the present study cultured rat hepatocytes were exposed to various GPCR agonists, including vasopressin, angiotensin II (Ang.II), norepinephrine, or prostaglandin F2α (PGF2α). None of these agents increased the phosphorylation of the EGFR or the docking protein Shc. Furthermore, we examined the effect of the GPCR agonists on the expression of two early response genes believed to be involved in growth activation. The GPCR agonists increased the mRNA expression of c‐myc, and also of activating transcription factor 3 (ATF3)/liver regeneration factor‐1 (LRF‐1), which is a novel finding. Finally, the selective EGFR inhibitor AG1478 did not suppress the activation of extracellular signal‐regulated kinase 1/2 (ERK1/2) or the induction of c‐myc or ATF3/LRF‐1 by the GPCR agonists, and did not prevent the comitogenic effects induced by these agents, while it blocked the effect of EGF on these responses. The results suggest that GPCR agonists induce expression of ATF3/LRF‐1 and c‐myc and exert comitogenic effects through mechanisms that do not require EGFR transactivation. © 2004 Wiley‐Liss, Inc.