Thermodynamic and electronic study of Ga-1 _ xMnxN films. A theoretical study

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Toward an understanding of intermediate- and short-range defects in ZnO single crystals. A combined experimental and theoretical study

A joint use of experimental and theoretical techniques allows us to understand the key role of intermediate- and short-range defects in the structural and electronic properties of ZnO single crystals obtained by means of both conventional hydrothermal and microwave-hydrothermal synthesis methods. X-ray diffraction, Raman spectra, photoluminescence, scanning electronic and transmission electron microscopies were used to characterize the thermal properties, crystalline and optical features of the obtained nano and microwires ZnO structures. In addition, these properties were further investigated by means of two periodic models, crystalline and disordered ZnO wurtzite structure, and first principles calculations based on density functional theory at the B3LYP level. The theoretical results indicate that the key factor controlling the electronic behavior can be associated with a symmetry breaking process, creating localized electronic levels above the valence band.

DEA and DSC study of cubic silsesquioxane epoxy resin nanocomposites

Non-isothermal dielectric analysis (DEA) and differential scanning calorimetry (DSC) techniques were used to study the epoxy nanocomposites prepared by reacting 1,3,5,7,9,11,13,15-octa[dimethylsiloxypropylglycidylether] pentaciclo [9.5.1.1(3,9).1(5,15).1(7,13)] octasilsesquioxane (ODPG) with methylenedianiline (MDA). Loss factor (epsilon) and activation energy were calculated by DEA. The relationships between the loss factor, the activation energy, the structure of the network, and the mechanical properties were investigated. Activation energies determined by DEA and DSC, heat of polymerization, fracture toughness and tensile modulus show the same profile for mechanical properties with respect to ODPG content.

Screening and Production Study of Microbial Xylanase Producers from Brazilian Cerrado

Hemicelluloses are polysaccharides of low molecular weight containing 100 to 200 glycosidic residues. In plants, the xylans or the hemicelluloses are situated between the lignin and the collection of cellulose fibers underneath. The xylan is the most common hemicellulosic polysaccharide in cell walls of land plants, comprising a backbone of xylose residues linked by beta-1,4-glycosidic bonds. So, xylanolytic enzymes from microorganism have attracted a great deal of attention in the last decade, particularly because of their biotechnological characteristics in various industrial processes, related to food, feed, ethanol, pulp, and paper industries. A microbial screening of xylanase producer was carried out in Brazilian Cerrado area in Selviria city, Mato Grosso do Sul State, Brazil. About 50 bacterial strains and 15 fungal strains were isolated from soil sample at 35 A degrees C. Between these isolated microorganisms, a bacterium Lysinibacillus sp. and a fungus Neosartorya spinosa as good xylanase producers were identified. Based on identification processes, Lysinibacillus sp. is a new species and the xylanase production by this bacterial genus was not reported yet. Similarly, it has not reported about xylanase production from N. spinosa. The bacterial strain P5B1 identified as Lysinibacillus sp. was cultivated on submerged fermentation using as substrate xylan, wheat bran, corn straw, corncob, and sugar cane bagasse. Corn straw and wheat bran show a good xylanase activity after 72 h of fermentation. A fungus identified as N. spinosa (strain P2D16) was cultivated on solid-state fermentation using as substrate source wheat bran, wheat bran plus sawdust, corn straw, corncob, cassava bran, and sugar cane bagasse. Wheat bran and corncobs show the better xylanase production after 72 h of fermentation. Both crude xylanases were characterized and a bacterial xylanase shows optimum pH for enzyme activity at 6.0, whereas a fungal xylanase has optimum pH at 5.0-5.5. They were stable in the pH range 5.0-10.0 and 5.5-8.5 for bacterial and fungal xylanase, respectively. The optimum temperatures were 55C and 60 A degrees C for bacterial and fungal xylanase, respectively, and they were thermally stable up to 50 A degrees C.

Diclofenac sodium and Imipenem action on rat intestinal mucosa: a biomechanical and histological study

OBJETIVO: Avaliar as alterações histológicas e biomecânicas do diclofenaco de sódio na mucosa intestinal do rato e a associação com o uso de Imipenem. MÉTODOS: Foram estudados 240 ratos Wistar distribuídos aleatoriamente em quatro grupos experimentais: GI: 60 ratos tratados com injeção IM de soro fisiológico 0,9%; GII: 60 ratos tratados com injeção IM de diclofenaco de sódio na dose de 6mg/kg de peso por 4 dias; GIII: 60 ratos tratados com injeção IM de Imipenem na dose de 30 mg/kg de peso por 4 dias; GIV: 60 ratos tratados com injeção IM de soro fisiológico e diclofenaco de sódio nas doses acima. em cada grupo os animais foram posteriormente divididos em 4 momentos de 15 animais em cada um para sacrifício, respectivamente, no 4º, 7º, 14º e 21º dias após o início do tratamento. As alterações da cavidade abdominal, assim como as características histológicas e de força de ruptura do intestino delgado foram analisadas em cada momento, em cada grupo. RESULTADOS: Não foram encontradas alterações histológicas e biomecânicas nos animais do Grupo I nesse estudo. Lesões ulceradas na mucosa do intestino delgado foram observadas nos animais tratados com diclofenaco de sódio, assim como diminuição da força de ruptura. As lesões ulceradas encontradas foram prevenidas pelo uso de Imipenem. CONCLUSÃO: O diclofenaco de sódio induz lesões ulceradas na mucosa intestinal do rato que podem ser prevenidas pelo uso de Imipenem.

Frequency and gravity of human envenomations caused by marine catfish (suborder siluroidei): a clinical and epidemiological study

Introduction and objectives: Catfish occur in marine and freshwater environments worldwide. They have three serrated venomous bony stings in the dorsal and pectoral fins that are used for defence against predators and are refilled by glandular tissues under the epithelium. However, some catfishes do not have poisonous glands next to the sting and cause traumatic wounds without poisoning. The objective of this study was to provide data for, and comment on, the epidemiological and clinical problems caused by marine catfish.Patients and methods: the authors have observed, followed and documented 127 injuries caused by marine catfish stings during different phases of the envenoming over a time period of 8 years at three points along the Western Atlantic Ocean coast.Results: the patients presented intense pain during the acute phase of envenoming and complications, such as bacterial and fungi infections and retention of bony fragments, in the later phase. Immersion of the affected extremity in hot water was used in about 20% of cases with excellent results.Discussion: Injuries caused by marine catfish are common (about 20% of injuries caused by marine animals in a series of more than 700 injuries recorded by the author) and cause intense pain and later complications. Immersion of the affected extremity in hot water results in improvement in the acute phase, but does not prevent the appearance of secondary infection or foreign body reactions. (c) 2006 Elsevier Ltd. All rights reserved.

SEABATHER'S ERUPTION: A CLINICAL and EPIDEMIOLOGICAL STUDY of 38 CASES IN SANTA CATARINA STATE, BRAZIL

Seabather's eruption (SBE) is an intensely itchy, papule-erythematous dermatitis that occurs predominantly in regions of the body covered by bathing costumes, after exposure to marine water. The planulae larvae of Linuche unguiculata scyphomedusae (thimble jellyfish) are the etiologic agent of the dermatitis, which is frequent in waters of Caribbean, Gulf of Mexico and Florida. The authors report 38 cases of SBE in the State of Santa Catarina (Southern region of Brazil), with emphasis on their clinical and epidemiological aspects, such as profile of victim, topography of the papules and conditions predisposing to the accident.

Dysphonia and laryngeal sequelae in paracoccidioidomycosis patients: a morphological and phoniatric study

The larynx is the third most commonly involved organ in paracoccidioidomycosis (PCM). While a few studies have evaluated laryngeal sequelae, there have not been any investigations of voice abnormalities in PCM patients. To evaluate persistent dysphonia and laryngeal lesions, we studied 15 normal subjects and 30 post-treatment PCM patients, i.e., 15 with only pulmonary and 15 with both laryngeal and pulmonary involvement. Perceptual and acoustic voice analysis were performed with all patients, while endoscopic studies were also conducted with the 15 laryngeal patients. Voice analysis showed instability by perceptual analysis (P < 0.01) in both groups, but more severe dysphonia was noted in the laryngeal group (P < 0.01). The dysponia, seen in 66.7% of these patients (dysphonia index < 7.0), was characterized by roughness and breathness. The Dr. Speech (Tiger Electronics) analysis program did not accept five voices from the laryngeal group due to the severe dysphonia. Jitter was elevated in five laryngeal lesion patients. Endoscopy showed that 80% of patients with laryngeal lesion had two or more laryngeal structures involved. Vocal fold alterations were seen in all laryngeal lesion patients, which included involvement of the arythenoids, epiglottis, and vestibular folds. This first functional study of laryngeal sequelae in PCM revealed frequent and severe dysphonia that may have important social consequences for patients.

TNF-308G > A Single Nucleotide Polymorphism Is Associated With Leprosy Among Brazilians: A Genetic Epidemiology Assessment, Meta-Analysis, and Functional Study

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Histological and immunohistochemical study of the expression of p53 and ki-67 proteins in the mucosa of the tongue, pharynx and larynx of rats exposed to cigarette smoke

Introduction: Head and neck cancers are linked to smoking. The most affected sites are the oral cavity, pharynx and larynx. Experimental studies show epithelial lesions caused by cigarette smoke. Objectives: To investigate in rats the effects of acute cigarette smoke exposure on the mucosa of the tongue, pharynx and larynx.Material and method: Wistar rats were allocated into two groups of 20 animals: CG (control) receiving food and water ad libitum and TG (Tobacco) exposed to the smoke of 40 cigarettes/day for 60 days. Biopsy of their tongues, pharynxes and larynxes were subjected to histopathological, histomorphometric and immunohistochemical studies of protein p53 and ki-67.Result: The histological analysis of tongue from the Tobacco group revealed epithelial hyperplasia (90%), basal cell hyperplasia (95%) and mild to moderate dysplasia (85%). In pharynx showed basal cell hyperplasia (85%), dysplasia (25%) and vascular congestion (95%). In larynx showed basal cell hyperplasia (70%), epithelial hyperplasia (55%), congestion (100%) and inflammatory infiltrate (25%). Morphometric analysis revealed that keratin layer thickness was greater in the tobacco group. P53 immunoexpression was negative in both groups. Ki-67 immunoexpression was positive in basal cell nuclei but in parabasal cell nuclei it was positive only in the Tobacco group.Conclusions: The exposure of animals to cigarette smoke for 60 days resulted in benign lesions. The duration of exposure was not enough to cause the development cancer, as confirmed by the negative expression of p53 protein in all slides examined. Analysis of ki-67 expression showed intense epithelial proliferation in response to damage.

EFFECTS of DIURON on MALE RAT REPRODUCTIVE ORGANS: A DEVELOPMENTAL and POSTNATAL STUDY

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Influence of the ratio of particulate autogenous bone graft/platelet-rich plasma on bone healing in critical-size defects: a histologic and histometric study in rat calvaria

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Bone healing in critical-size defects treated with platelet-rich plasma activated by two different methods. A histologic and histometric study in rat calvaria

The purpose of this study was to analyze histologically the influence of platelet-rich plasma (PRP) coagulated with two different activators on bone healing in surgically created critical-size defects (CSD) in rat calvaria.Forty-eight rats were divided into three groups: C, PRP-C and PRP-T. An 8 mm diameter CSD was created in the calvarium of each animal. In group C, the defect was filled by a blood clot only. In groups PRP-C and PRP-T, the defect was filled with PRP activated with either calcium chloride or thromboplastin solution, respectively. Each group was divided into two subgroups (n = 8 per subgroup) and killed at either 4 or 12 weeks postoperatively. Histologic and histometric analyses were performed. The amount of new bone formed was calculated as a percentage of the total area of the original defect. Percentage data were transformed into arccosine for statistical analysis (analysis of variance, Tukey's post hoc test, p < 0.05).No defect completely regenerated with bone. Group PRP-C had a statistically greater amount of bone formation than groups C and PRP-T at both time points of analysis. No statistically significant differences were observed between groups C and PRP-T.It can be concluded that the type of activator used to initiate PRP clot formation influences its biological effect on bone healing in CSD in rat calvaria.

Surface and Biomechanical Study of Titanium Implants Modified by Laser With and Without Hydroxyapatite Coating, in Rabbits

Surface and biomechanical analysis of titanium implant surfaces modified by laser beam with and without hydroxyapatite. Titanium implants with 3 different surfaces were inserted into the tibias of 30 rabbits: group I (GI) machined surface (control group), group II irradiated with laser (GII), and group III irradiated with laser and hydroxyapatite coating applied-biomimetic method (GIII). Topographical analysis with scanning electron microscopy was made before surgery in the tibia. These rabbits were distributed into 2 periods of observation: 4 and 8 weeks postsurgery, after which biomechanical analysis (removal torque) was conducted. Statistical analysis used the Student-Newman-Keuls method. Surface showed roughness in GII and GIII. Biomechanical analysis demonstrated values with significant differences in GII and GIII. Titanium implants modified by laser irradiation can increase osseointegration during the initial phase.

Influence of Bioactive Glass and/or Acellular Dermal Matrix on Bone Healing of Surgically Created Defects in Rat Tibiae: A Histological and Histometric Study

The purpose of this study was to histologically analyze the influence of bioactive glass and/or acellular dermal matrix on bone healing in surgically created defects in the tibiae of 64 rats (Rattus norvegicus, albinus, Wistar). Materials and Methods: A 4-mm X 3-mm unicortical defect was created on the anterolateral surface of the tibia. Animals were divided into 4 groups: C, control; BG, the defect was filled with bioactive glass; ADM, the defect was covered with acellular dermal matrix; and BG/ADM, the defect was filled with bioactive glass and covered with acellular dermal matrix. Animals were sacrificed at 10 or 30 days postoperatively, and the specimens were removed for histologic processing. The formation of new bone in the cortical area of the defect was evaluated histomorphometrically. Results: At 10 and 30 days postoperatively, groups C (39.65% +/- 5.63% / 63.34% +/- 5.22%) and ADM (38.12% +/- 5.53 / 58.96% +/- 7.05%) presented a larger amount of bone formation compared to the other groups (P<.05). In the same periods, groups BG (13.10% +/- 6.29% / 29.5% +/- 5.56%) and BG/ADM (20.72% +/- 8.31% / 24.19% +/- 6.69%) exhibited statistically similar new bone formation. However, unlike the other groups, group BG/ADM did not present a significant increase in bone formation between the 2 time points. Conclusion: Based on these results, it can be concluded that all of the materials used in this study delayed bone healing in non-critical-size defects. INT J ORAL MAXILLOFAC IMPLANTS 2008;23:811-817