986 resultados para 681.3:656.1
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The SU(3)cxSU(3)LxU(1)N model of Pisano and Pleitez extends the standard model in a particularly nice way, so that, for example, the anomalies cancel only when the number of generations is divisible by 3. The original version of the model has some problems accounting for the lepton masses. We resolve this problem by modifying the details of the symmetry-breaking sector in the model.
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Mononuclear pyrazolyl Pd(II) complexes of the type [PdX2(phmPz)(2)] (X = Cl-, N-3(-)) have been prepared. The 1-phenyl-3-methylpyrazole displaces acetonitrile from [PdCl2(CH3CN)(2)] to form [PdCl2(PhMPz)(2)] (phmPz = 1-phenyl-3-methylpyrazole) (1). [Pd(N-3)(2)(PhmPz)(2)] (2) could be obtained by metathesis from [PdCl2(CH3CN)(2)] or by substitution of the chloride in (1) by the azide ion. Both complexes were characterized by elemental analysis, infrared spectroscopy, H-1 and C-13 NMR and by single crystal X-ray diffraction. The coordination geometry around Pd(II) in these complexes is nearly square-planar, with the ligands in a trans configuration.
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We consider a gauge model based on a SU(3)XU(1) symmetry in which the lepton number is violated explicitly by charged scalar and gauge bosons, including a vector field with double electric
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1-Benzoyl-3-benzylguanidine and 1-benzoyl-3-benzyl-O-ethylisourea were synthesized in good yields (68 and 76%, respectively) from 1-benzoyl-3-benzylthiourea and benzoyl-ethylthiocarbamate in dry media conditions using KF-Al2O3 under microwave irradiation. Strong nucleophilic amines promoted the sulfur elimination by attack on the thiocarbonyl group in both thiourea and thiocarbamates to afford guanidines and isourea, respectively. Transesterification products were obtained from p-TsOH catalyzed reaction of thiocarbamate with alcohols under MW-solvent-free conditions. Very important non-purely thermal MW specific effects were evidenced and attributed to stabilization by coulombic interactions between materials and waves. (c) 2005 Elsevier Ltd. All rights reserved.
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The sesquiterpenes cadina-4,10(15)-dien-3-one (1) and aromadendr-1(10)-en-9-one (squamulosone) (14) along with the triterpenoid methyl ursolate (21) were incubated with the fungus Mucor plumbeus ATCC 4740. Substrates 1, 14 and ursolic acid (20) were isolated from the plant Hyptis verticillata in large quantities. M. plumbeus hydroxylated 1 at C-12 and C-14. When the iron content of the medium was reduced, however, hydroxylation at these positions was also accompanied by epoxidation of the exocyclic double bond. In total nine new oxygenated cadinanes have been obtained. Sesquiterpene 14 was converted to the novel 2α,13-dihydroxy derivative along with four other metabolites. Methyl ursolate (21) was transformed to a new compound, methyl 3β,7β,21β-trihydroxyursa-9(11),12-dien-28-oate (22). Two other triterpenoids, 3β,28-dihydroxyurs-12-ene (uvaol) (23) and 3β,28-bis(dimethylcarbamoxy)urs-12-ene (24) were not transformed by the micro-organism, however. © 2002 Elsevier Science Ltd. All rights reserved.
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Incluye Bibliografía
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Pós-graduação em Biofísica Molecular - IBILCE
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Pós-graduação em Ciências Biológicas (Microbiologia Aplicada) - IBRC
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1,3-propanediol is a high-value specialty chemical which has many industrial applications. Its main use is the production of the polymer polypropylene terephthalate, a thermoplastic used in the textile and automobile industries. The interest in 1,3-propanediol production from glycerol bio-conversion has increased after the employment of biodiesel by various countries, being produced by chemical synthesis from petroleum intermediates or biotechnologically by microbial fermentation. Glycerol is an abundant low-cost byproduct from biodiesel refineries, and it is the only substrate that can be naturally or enzymatically converted to 1,3-propanediol by microbial fermentation. In this review, information on 1,3-propanediol's importance, production and purification are presented, along with results from recent research on glycerol microbial conversion to 1,3-propanediol. The bio-production of this intermediate compound from glycerol is very attractive both economically and environmentally, since it allows the replacement of fossil fuels by renewable resources.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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PURPOSE: To compare gene expression of the chemokines RANTES and eotaxin-2, its receptor, CCR-3, adhesion molecule ICAM-1 and its receptor LFA-1 in eosinophilic polyps and in control normal nasal mucosa. METHODS: Gene expression was quantified by Real Time PCR in polyps (n=35) and in healthy nasal mucosa (n=15). RESULTS: Eosinophilic polyps showed a higher expression of eotaxin-2 and RANTES, but not of CCR-3, ICAM-1 or LFA-1 compared to control nasal mucosa. CONCLUSION: Eosinophilic polyps present greater expression of eotaxin-2 and RANTES, but not of CCR-3, ICAM-1 or LFA-1 compared to control nasal mucosa.
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PURPOSE: Facial esthetics play an important role in social interactions. However, children with a repaired complete unilateral cleft lip and palate usually show some disfigurement of the nasolabial area. To date, few studies have assessed the nasolabial appearance after different treatment protocols. The aim of the present study was to compare the nasolabial esthetics after 1- and 3-stage treatment protocols. MATERIALS AND METHODS: Four components of the nasolabial appearance (nasal form, nasal deviation, mucocutaneous junction, and profile view) were assessed by 4 raters in 108 consecutively treated children who had undergone either 1-stage closure (Warsaw group, 41 boys and 19 girls, mean age 10.8 years, SD 2.0) or 3-stage (Nijmegen group, 30 boys and 18 girls, mean age 8.9 years, SD 0.7). A 5-grade esthetic index of Asher-McDade was used, in which grade 1 indicates the most esthetic and grade 5 the least esthetic outcome. RESULTS: The nasal form was judged the least esthetic in both groups and graded 3.1 (SD 1.1) and 3.2 (SD 1.1). The nasal deviation, mucocutaneous junction, and profile view were scored from 2.1 (SD 0.8) to 2.3 (SD 1.0) in both groups. The treatment outcome after the Warsaw and Nijmegen protocols was comparable. Neither overall nor any of the 4 components of the nasolabial appearance showed intercenter differences (P > .1). CONCLUSIONS: The nasolabial appearance after the Warsaw (1-stage) and Nijmegen (3-stage) protocols was comparable. The technique of lip repair (triangular flap in Warsaw and Millard rotation advancement in Nijmegen) gave comparable results for the esthetics of the nasolabial area.
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Three-dimensional oxalate-based {[Ru(bpy)3][Cu2xNi2(1-x)(ox)3]}n (0≤ x ≤ 1, ox = C2O42-, bpy = 2,2‘bipyridine) were synthesized. The structure was determined for x = 1 by X-ray diffraction on single crystal. The compound crystallizes in the cubic space group P4132. It shows a three-dimensional 10-gon 3-connected (10,3) anionic network where copper(II) has an unusual tris(bischelated) environment. X-ray powder diffraction patterns and their Rietveld refinement show that all the compounds along the series are isostructural and single-phased. According to X-ray absorption spectroscopy, copper(II) and nickel(II) have an octahedral environment, respectively elongated and trigonally distorted. As shown by natural circular dichroism, the optically active forms of {[Ru(bpy)3][CuxNi2(1-x)(ox)3]}n are obtained starting from resolved Δ- or Λ-[Ru(bpy)3]2+. The Curie−Weiss temperatures range between −55 (x = 1) and −150 K (x = 0). The antiferromagnetic exchange interaction thus decreases when the copper contents increases in agreement with the crystallographic structure of the compounds and the electronic structure of the metal ions. At low temperature, the compounds exhibit complex long-range ordered magnetic behavior.
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Changes in (1→3,1→4)-β-D-glucan endohydrolase (EC 3.2.1.73) protein levels were investigated in segments from second leaves of wheat (Triticum aestivum L.). The abundance of the enzyme protein markedly increased when leaf segments were incubated in the dark whereas the enzyme rapidly disappeared when dark-incubated segments were illuminated or fed with sucrose. Addition of cycloheximide (CHI) to the incubation medium led to the disappearance of previously synthesized (1→3,1→4)-β-glucanase and suppressed the dark-induced accumulation indicating that the enzyme was rather unstable. The degradation of (1→3,1→4)-β-glucanase was analyzed without the interference of de-novo synthesis in intercellular washing fluid (IWF). The loss of the enzyme protein during incubation of IWF (containing naturally present peptide hydrolases) indicated that the stability increased from pH 4 to pH 7 and that an increase in the temperature from 25 to 35 °C considerably decreased the stability. Chelating divalent cations in the IWF with o-phenanthroline also resulted in a lowered stability of the enzyme. A strong temperature effect in the range from 25 to 35 °C was also observed in wheat leaf segments. Diurnal changes in (1→3,1→4)-β-glucanase activity were followed in intact second leaves from young wheat plants. At the end of the dark period, the activity was high but constantly decreased during the light phase and remained low if the light period was extended. Activity returned to the initial level during a 10-h dark phase. During a diurnal cycle, changes in (1→3,1→4)-β-glucanase activity were associated with reciprocal changes in soluble carbohydrates. The results suggest that the synthesis and the proteolytic degradation of an apoplastic enzyme may rapidly respond to changing environmental conditions.