986 resultados para III-V Nitrides
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We study the evolution of structural defects in AlxGa1-xN films (with x=0.0-0.6) bombarded with kilo-electron-volt heavy ions at 77 and 300 K. We use a combination of Rutherford backscattering/channeling spectrometry and cross-sectional transmission electron microscopy. Results show that an increase in Al content not only strongly enhances dynamic annealing processes but can also change the main features of the amorphization behavior. In particular, the damage buildup behavior at 300 K is essentially similar for all the AlGaN films studied. Ion-beam-produced disorder at 300 K accumulates preferentially in the crystal bulk region up to a certain saturation level (similar to50%-60% relative disorder). Bombardment at 300 K above a critical fluence results in a rapid increase in damage from the saturation level up to complete disordering, with a buried amorphous layer nucleating in the crystal bulk. However, at 77 K, the saturation effect of lattice disorder in the bulk occurs only for xgreater than or similar to0.1. Based on the analysis of these results for AlGaN and previously reported data for InGaN, we discuss physical mechanisms of the susceptibility of group-III nitrides to ion-beam-induced disordering and to the crystalline-to-amorphous phase transition. (C) 2004 American Institute of Physics.
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Trägerband: Inc. oct. 473; 'Homil. cath. 686a'; Vorbesitzer: Dominikanerkloster Frankfurt am Main
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The objective of the study was to illustrate the applicability and significance of the novel Lewis urothelial cancer model compared to the classic Fisher 344. Fischer 344 and Lewis females rats, 7 weeks old, were intravesical instilled N-methyl-N-nitrosourea 1.5 mg/kg every other week for a total of four doses. After 15 weeks, animals were sacrificed and bladders analyzed: histopathology (tumor grade and stage), immunohistochemistry (apoptotic and proliferative indices) and blotting (Toll-like receptor 2-TLR2, Uroplakin III-UP III and C-Myc). Control groups received placebo. There were macroscopic neoplastic lesions in 20 % of Lewis strain and 70 % of Fischer 344 strain. Lewis showed hyperplasia in 50 % of animals, normal bladders in 50 %. All Fischer 344 had lesions, 20 % papillary hyperplasia, 30 % dysplasia, 40 % neoplasia and 10 % squamous metaplasia. Proliferative and apoptotic indices were significantly lower in the Lewis strain (p < 0.01). The TLR2 and UP III protein levels were significantly higher in Lewis compared to Fischer 344 strain (70.8 and 46.5 % vs. 49.5 and 16.9 %, respectively). In contrast, C-Myc protein levels were significantly higher in Fischer 344 (22.5 %) compared to Lewis strain (13.7 %). The innovative Lewis carcinogen resistance urothelial model represents a new strategy for translational research. Preservation of TLR2 and UP III defense mechanisms might drive diverse urothelial phenotypes during carcinogenesis in differently susceptible individuals.
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Angle Class III malocclusion has been a challenge for researchers concerning diagnosis, prognosis and treatment. It has a prevalence of 5% in the Brazilian population, and may have a genetic or environmental etiology. This malocclusion can be classified as dentoalveolar, skeletal or functional, which will determine the prognosis. Considering these topics, the aim of this study was to describe and discuss a clinical case with functional Class III malocclusion treated by a two-stage approach (interceptive and corrective), with a long-term follow-up. In this case, the patient was treated with a chincup and an Eschler arch, used simultaneously during 14 months, followed by corrective orthodontics. It should be noticed that, in this case, initial diagnosis at the centric relation allowed visualizing the anterior teeth in an edge-to-edge relationship, thereby favoring the prognosis. After completion of the treatment, the patient was followed for a 10-year period, and stability was observed. The clinical treatment results showed that it is possible to achieve favorable outcomes with early management in functional Class III malocclusion patients.
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This article reports the case of a 19-year-old young man with Class III malocclusion and posterior crossbite with concerns about temporomandibular disorder (TMD), esthetics and functional problems. Surgical-orthodontic treatment was carried out by decompensation of the mandibular incisors and segmentation of the maxilla in 4 pieces, which allowed expansion and advancement. Remission of the signs and symptoms occurred after surgical-orthodontic intervention. The maxillary dental arch presented normal transverse dimension. Satisfactory static and functional occlusion and esthetic results were achieved and remained stable. Three years after the surgical-orthodontic treatment, no TMD sign or symptom was observed and the occlusal results had not changed. When vertical or horizontal movements of the maxilla in the presence of moderate maxillary constriction are necessary, segmental LeFort I osteotomy can be an important part of treatment planning.
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Class III skeletal malocclusion may present several etiologies, among which maxillary deficiency is the most frequent. Bone discrepancy may have an unfavorable impact on esthetics, which is frequently aggravated by the presence of accentuated facial asymmetries. This type of malocclusion is usually treated with association of Orthodontics and orthognathic surgery for correction of occlusion and facial esthetics. This report presents the treatment of a patient aged 15 years and 1 month with Class III skeletal malocclusion, having narrow maxilla, posterior open bite on the left side, anterior crossbite and unilateral posterior crossbite, accentuated negative dentoalveolar discrepancy in the maxillary arch, and maxillary and mandibular midline shift. Clinical examination also revealed maxillary hypoplasia, increased lower one third of the face, concave bone and facial profiles and facial asymmetry with mandibular deviation to the left side. The treatment was performed in three phases: presurgical orthodontic preparation, orthognathic surgery and orthodontic finishing. In reviewing the patient's final records, the major goals set at the beginning of treatment were successfully achieved, providing the patient with adequate masticatory function and pleasant facial esthetics.
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In this work we have studied cyclooctene epoxidation with PhIO, using a new iron porphyrin, 5,10,15,20-tetrakis(2-hydroxy-5-nitrophenyl)porphyrinato iron(III), supported on silica matrices via eletrostatic interaction and / or covalent bonds as catalyst. These catalysts were obtained and immobilized on the solid supports propyltrimethylammonium silica (SiN+); propyltrimethylammonium and propylimidazole silica [SiN+(IPG)] and chloropropylsilica (CPS) via elestrostatic interactions and covalent binding. Characterization of the supported catalysts by UV-Vis spectroscopy and EPR (Electron paramagnetic resonance) indicated the presence of a mixture of FeII and FeIII species in all of the three obtained catalysts. In the case of (Z)-cyclooctene epoxidation by PhIO the yields observed for cis-epoxycyclooctane were satisfactory for the reactions catalyzed by the three materials (ranging from 68% to 85%). Such results indicate that immobilization of metalloporphyrins onto solid supports via groups localized on the ortho positions of their mesophenyl rings can lead to efficient catalysts for epoxidation reactions. The catalyst 1-CPS is less active than 1-SiN and 1-SiN(IPG), this argues in favour of the immobilization of this metalloporphyrin onto solids via electrostatic interactions, which is easier to achieve and results in more active oxidation catalysts. Interestingly, the activity of the supported catalysts remained the same even after three successive recyclings; therefore, they are stable under the oxidizing conditions.
Metal-free synthesis of indanes by iodine(III)-mediated ring contraction of 1, 2-dihydronaphthalenes
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A metal-free protocol was developed to synthesize indanes by ring contraction of 1, 2-dihydronaphthalenes promoted by PhI(OH)OTs (HTIB or Koser's reagent). This oxidative rearrangement can be performed in several solvents (MeOH, CH3CN, 2 , 2, 2-trifluoroethanol (TFE), 1 , 1, 1, 3, 3, 3-hexafluoroisopropanol (HFIP), and a 1:4 mixture of TFE:CH2Cl2) under mild conditions. The ring contraction diastereoselectively gives functionalized trans-1, 3-disubstituted indanes, which are difficult to obtain in synthetic organic chemistry
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Oitenta e quatro espécies são registradas para o Estado do Maranhão: Prioninae (uma), Disteniinae (uma), Cerambycinae (49) e Lamiinae (33). O número total de espécies assinaladas para o Estado eleva-se a 367. Nove novas espécies são descritas em Cerambycinae: Chlorida inexpectata sp. nov. (Bothriospilini); Jupoata germana sp. nov. (Cerambycini); Eburodacrys separatus sp. nov. e Eburodacrys cincora sp. nov. (Eburiini); Ectenessa affinis sp. nov. (Ectenessini); Minibidion bicolor sp. nov. (Ibidionini, Tropidiina); Compsibidion maculatum sp. nov. e Compsibidion ytu sp. nov. (Ibidionini,Ibidionina); Ideratus beatus sp. nov. (Ideratini). Três espécies são descritas em Lamiinae: Aerenea gibba sp. nov. (Compsosomatini); Mimasyngenes barbozai sp. nov. (Desmiphorini); Cacostola exilis sp. nov. (Onciderini). Uma variação no colorido de Adesmus paradiana Galileo & Martins, 2004 é observada. Corrigenda de Piruana pulchra Martins et al., 2009 para Piruauna pulchra (Desmiphorini).
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Oxyommata Zajciw, 1970 e O. collaris (Audinet-Serville, 1833) são redescritos e comentados. Um novo gênero proveniente da divisão de Xenocrasis Bates, 1873 é descrito e três espécies alocadas nele: X. fulvicollis(Lacordaire, 1868); X. pubipennis (Fisher, 1952); e X. vestitipennis Zajciw, 1963. É apresentada chave para as espécies do novo gênero.
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Caracteres genéricos são ampliados para Irundisaua Martins & Galileo, 2005 (configuração das antenas; processo prosternal com largura menor ou igual à largura de uma procoxa; protíbias achatadas e fortemente alargadas para o ápice) ao qual se adicionam espécies transferidas de Acanthoderes Audinet-Serville, 1835: I. forsteri (Tippmann, 1960) comb. nov. do Peru e Brasil (Amazonas) e I. ucayalensis (Tippmann, 1960) comb. nov. do Equador, Peru e Brasil (Amazonas).Três novos gêneros são descritos: (1) Catuana comb. nov., espécie-tipo, C. thoracica (Tippmann, 1960) comb. nov., caracterizado pelo mesosterno com tubérculo; (2) Mundeu comb. nov., espécie-tipo, M. maculicollis (Bates, 1861) comb. nov., com protórax arredondado nos lados e protíbias alargadas; (3) Urangaua comb. nov., caracteriza-se pelos olhos finamente facetados e divididos, comprimento dos antenômeros III e IV subigual ao comprimento dos antenômeros V-XI em conjunto; é proposto para duas espécies: U. analis Melzer, 1935, comb. nov., espécietipo, e U. subanalis (Zajciw, 1964) comb. nov. Adiciona-se chave para as espécies de Urangaua.
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Novas espécies da Guiana Francesa são descritas e figuradas: Trestonia bilineta sp. nov. (Onciderini); Ischnolea odettae sp. nov. (Desmiphorini); Oreodera mageia sp. nov. (Acanthoderini) e Icupima ampliata sp. nov. (Hemilophini). Faz-se um novo registro de Plocaederus fragosoi (Cerambycini) para a Guiana Francesa.
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São discriminados em chave os gêneros semelhantes a Anoreina Bates, 1861, Trichoanoreina Julio & Monné, 2005 e Pyrianoreina gen. nov. Espécies novas descritas: Pyrianoreina piranga sp. nov. do Equador; P. hovorei sp. nov. da Bolívia; do Brasil Anoreina piara sp. nov. (Pará) e A. pinimaiuba sp. nov. (Amazonas); A. ayri sp. nov. do Equador.
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Background: Spinal muscular atrophy (SMA) is an autosomal recessive disorder that affects the motoneurons of the spinal anterior horn, resulting in hypotonia and muscle weakness. The disease is caused by deletion or mutation in the telomeric copy of SMN gene (SMN1) and clinical severity is in part determined by the copy number of the centromeric copy of the SMN gene (SMN2). The SMN2 mRNA lacks exon 7, resulting in a production of lower amounts of the full-length SMN protein. Knowledge of the molecular mechanism of diseases has led to the discovery of drugs capable of increasing SMN protein level through activation of SMN2 gene. One of these drugs is the valproic acid (VPA), a histone deacetylase inhibitor. Methods: Twenty-two patients with type II and III SMA, aged between 2 and 18 years, were treated with VPA and were evaluated five times during a one-year period using the Manual Muscle Test (Medical Research Council scale-MRC), the Hammersmith Functional Motor Scale (HFMS), and the Barthel Index. Results: After 12 months of therapy, the patients did not gain muscle strength. The group of children with SMA type II presented a significant gain in HFMS scores during the treatment. This improvement was not observed in the group of type III patients. The analysis of the HFMS scores during the treatment period in the groups of patients younger and older than 6 years of age did not show any significant result. There was an improvement of the daily activities at the end of the VPA treatment period. Conclusion: Treatment of SMA patients with VPA may be a potential alternative to alleviate the progression of the disease.
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Sinovitis in Scleroderma (SSc) is rare, usually aggressive and fully resembles rheumatoid arthritis. Experimental models of SSc have been used in an attempt to understand its pathogenesis. Previous studies done in our laboratory had already revealed the presence of a synovial remodeling process in rabbits immunized with collagen V. To validate the importance of collagen type V and to explore the quantitative relationship between this factor and synovia remodeling as well as the relationship between collagen type V and other collagens, we studied the synovial tissue in immunized rabbits. Rabbits (N= 10) were immunized with collagen V plus Freund's adjuvant and compared with animals inoculated with adjuvant only (N= 10). Synovial tissues were submitted to histological analysis, immunolocalization to collagen I, III and V and biochemical analysis by eletrophoresis, immunoblot and densitometric method. The synovial tissue presented an intense remodeling process with deposits of collagen types I, III and V after 75 and 120 days of immunization, mainly distributed around the vessels and interstitium of synovial extracellular matrix. Densitometric analysis confirmed the increased synthesis of collagen I, III and V chains (407.69 +/- 80.31; 24.46 +/- 2.58; 70.51 +/- 7.66, respectively) in immunized rabbits when compared with animals from control group (164.91 +/- 15.67; 12.89 +/- 1.05; 32 +/- 3.57) (p<0.0001). We conclude that synovial remodeling observed in the experimental model can reflect the articular compromise present in patients with scleroderma. Certainly, this experimental model induced by collagen V immunization will bring new insights in to pathogenic mechanisms and allow the testing of new therapeutic strategies to ameliorate the prognosis for scleroderma patients.