Aplicação dos isótopos estáveis em aqüicultura

O produto mais importante do conhecimento é a ignorância. A situação sugere a imagem de alguém que vive numa ilha de conhecimento cercado por um mar de ignorância. Quando a área dessa ilha aumenta pelo progresso da ciência, também aumenta o litoral, - a fronteira com o desconhecido. Esta expansão é o fruto mais valioso do conhecimento (David Gross, Nobel em Física, 2004). O uso dos isótopos estáveis dos bioelementos (CHON'S) presentes na Atmosfera, Hidrosfera, Litosfera e Biosfera enquadra-se neste contexto, surgindo como ferramenta de alto potencial em pesquisas nas diversas áreas das Ciências da Vida. Com organismos aquáticos, a aplicação dos isótopos estáveis do carbono (δ 13C) e do nitrogênio (δ 15N) tem ocorrido em diversas áreas. em larvas de pacu Piaractus mesopotamicus, a técnica evidenciou a escolha voluntária entre organismos vivos e dieta seca pelos animais, desde as primeiras alimentações até o final da larvicultura. Na carcinicultura, o crescimento do Penaeus vannamei resultou do aproveitamento dos alimentos oferecidos e da produtividade primária do lago (biota). Por meio do balanço de massa e isotópico foi possível determinar a contribuição da biota, da ordem de 44 a 86% do carbono assimilado pelos animais durante o crescimento. Outro exemplo é com o caranguejo de mangue Sesarma rectum, em que sua preferência alimentar por Spartina alterniflora (C4) versus Rhizophora mangle (C3) ou Hibiscus tiliaceus (C3) foi evidenciada pelo modelo isotópico de duas fontes alimentares e os isótopos estáveis do carbono (δ13C). A técnica dos isótopos estáveis associada ao conhecimento dos conceitos básicos da variabilidade isotópica natural e ao uso criterioso das razões 13C/12C; ²H/¹H; 18O/16O; 15N/14N e 36S/34S revela-se como um avanço na fronteira dos conhecimentos, nas diversas reentrâncias do litoral da aqüicultura.

Bone reformation and implant integration following maxillary sinus membrane elevation: An experimental study in primates

Background: Recent clinical studies have described maxillary sinus floor augmentation by simply elevating the maxillary sinus membrane without the use of adjunctive grafting materials. Purpose: This experimental study aimed at comparing the histologic outcomes of sinus membrane elevation and simultaneous placement of implants with and without adjunctive autogenous bone grafts. The purpose was also to investigate the role played by the implant surface in osseointegration under such circumstances. Materials and Methods: Four tufted capuchin primates had all upper premolars and the first molar extracted bilaterally. Four months later, the animals underwent maxillary sinus membrane elevation surgery using a replaceable bone window technique. The schneiderian membrane was kept elevated by insertion of two implants (turned and oxidized, Brånemark System®, Nobel Biocare AB, Göteborg, Sweden) in both sinuses. The right sinus was left with no additional treatment, whereas the left sinus was filled with autogenous bone graft. Implant stability was assessed through resonance frequency analysis (Osstell™, Integration Diagnostics AB, Göteborg, Sweden) at installation and at sacrifice. The pattern of bone formation in the experimental sites and related to the different implant surfaces was investigated using fluorochromes. The animals were sacrificed 6 months after the maxillary sinus floor augmentation procedure for histology and histomorphometry (bone-implant contact, bone area in threads, and bone area in rectangle). Results: The results showed no differences between membrane-elevated and grafted sites regarding implant stability, bone-implant contacts, and bone area within and outside implant threads. The oxidized implants exhibited improved integration compared with turned ones as higher values of bone-implant contact and bone area within threads were observed. Conclusions: The amount of augmented bone tissue in the maxillary sinus after sinus membrane elevation with or without adjunctive autogenous bone grafts does not differ after 6 months of healing. New bone is frequently deposited in contact with the schneiderian membrane in coagulum-alone sites, indicating the osteoinductive potential of the membrane. Oxidized implants show a stronger bone tissue response than turned implants in sinus floor augmentation procedures. © 2006 Blackwell Publishing, Inc.

Histological findings following the use of a space-making device for bone reformation and implant integration in the maxillary sinus of primates

Background: Previous studies have shown that membrane elevation results in predictable bone formation in the maxillary sinus provided that implants can be placed as tent poles. In situations with an extremely thin residual crest which impairs implant placement, it is possible that a space-making device can be used under the sinus membrane to promote bone formation prior to placement of implants. Purpose: The present study was conducted to test the hypothesis that the use of a space-making device for elevation of the sinus membrane will result in predictable bone formation at the maxillary sinus floor to allow placement of dental implants. Materials and Methods: Eight tufted capuchin primates underwent bilateral sinus membrane elevation surgery, and a bioresorbable space-making device, about 6 mm wide and 6 mm in height, was placed below the elevated membrane on the sinus floor. An oxidized implant (Nobel Biocare AB, Gothenburg, Sweden) was installed in the residual bone protruding into the created space at one side while the other side was left without an implant. Four animals were sacrificed after 6 months of healing. The remaining four animals received a second implant in the side with a space-making device only and followed for another 3 months before sacrifice. Implant stability was assessed through resonance frequency analysis (RFA) using the Osstell™ (Osstell AB, Gothenburg, Sweden) at installation, 6 months and 9 months after the first surgery. The bone-implant contact (BIC) and bone area inside the threads (BA) were histometrically evaluated in ground sections. Results: Histologically there were only minor or no signs of bone formation in the sites with a space-making device only. Sites with simultaneous implant placement showed bone formation along the implant surface. Sites with delayed implant placement showed minor or no bone formation and/or formation of a dense fibrous tissue along the apical part of the implant surface. In the latter group the apical part of the implant was not covered with the membrane but protruded into the sinus cavity. Conclusions: The use of a space-making device, with the design used in the present study, does not result in bone formation at the sinus floor. However, membrane elevation and simultaneous placement of the device and an implant does result in bone formation at the implant surface while sites with implants placed 6 months after membrane elevation show only small amounts of bone formation. It is suggested that lack of stabilization of the device and/or a too extensive elevation of the membrane may explain the results. © 2009, Wiley Periodicals, Inc.

Implant osseointegration in circumferential bone defects treated with latex-derived proteins or autogenous bone in dog's mandible

Background: In sites with diminished bone volume, the osseointegration of dental implants can be compromised. Innovative biomaterials have been developed to aid successful osseointegration outcomes. Purpose: The aim of this study was to evaluate the osteogenic potential of angiogenic latex proteins for improved bone formation and osseointegration of dental implants. Materials and Methods: Ten dogs were submitted to bilateral circumferential defects (5.0×6.3mm) in the mandible. Dental implant (3.3×10.0mm, TiUnite MK3™, Nobel Biocare AB, Göteborg, Sweden) was installed in the center of the defects. The gap was filled either with coagulum (Cg), autogenous bone graft (BG), or latex angiogenic proteins pool (LPP). Five animals were sacrificed after 4 weeks and 12 weeks, respectively. Implant stability was evaluated using resonance frequency analysis (Osstell Mentor™, Osstell AB, Göteborg, Sweden), and bone formation was analyzed by histological and histometric analysis. Results: LPP showed bone regeneration similar to BG and Cg at 4 weeks and 12 weeks, respectively (p≥.05). Bone formation, osseointegration, and implant stability improved significantly from 4 to 12 weeks (p≤.05). Conclusion: Based on methodological limitations of this study, Cg alone delivers higher bone formation in the defect as compared with BG at 12 weeks; compared with Cg and BG, the treatment with LPP exhibits no advantage in terms of osteogenic potential in this experimental model, although overall osseointegration was not affected by the treatments employed in this study. © 2009 Wiley Periodicals, Inc.

Influence of natural polymer derived from starch as a sensory modifier in sunscreen formulations

Background: Nowadays, there has been increased incidence of skin cancer, which is mainly related to increased sun exposure. Although sunscreen products may prevent the appearing of this disease, consumers may not use them due to some factors, including the sensory properties. The Aluminum Starch Octenylsuccinate (Dry-Flo® Pure, Akzo Nobel), an aluminum salt produced by the reaction of anhydride octenylsuccinic with starch, is able to improve the spreadability on the skin and reduce the oiliness of the formulation. Objective: To verify volunteers' acceptance for sunscreen formulation with natural polymer, compared with a control formulation (without polymer). Methods: To carry out the sensory analysis a formulation with or without 2. 0% Aluminum Starch Octenylsuccinate was prepared. Formulations had FPS 15, with critical wavelength of 353 nm, determined by testing in silico using the BASF® Sunscreen Simulator. Sensory analysis was performed on 60 students of both sexes, aged between 18 and 25 years, regular users of sunscreen products. Results: The results suggested that the polymer was able to promote a very soft and velvety feel on the skin when used in a sunscreen formulation, and it was able to mitigate and noticeably reduce the oiliness of the skin. Of the 60 volunteers who participated in the study, 45 volunteers (75%) considered that the polymer formulation provides little brightness or did not notice the difference in brightness of the skin after application. Conclusions: It was able to improve the sensory of the product, contributing to greater volunteers' acceptance.

Atrasos e turbulências na educação brasileira

Incluye Bibliografía

Osseointegração de implantes usinados e oxidados em seio maxilar preenchido por coágulo com ou sem osso autógeno: estudo histológico, histométrico e de RFA em macacos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação espectrofotométrica de diferentes sistemas cerâmicos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A poesia plural de Pablo Neruda

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência do número e inclinação dos implantes para a ancoragem de prótese fixa em maxila atrófica: estudo comparativo com elementos finitos 3D

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A desumana neutralidade da métrica

A frase que serve de título a este trabalho foi recolhida de um ensaio sobre a poetisa russa Anna Akhmatova, escrito pelo poeta e crítico Joseph Brodsky (1994) e intitulado A musa lastimosa. O apreço negativo em que, ali, o crítico tem à métrica - efeito do emprego do adjetivo desumana e, até certo ponto, do substantivo neutralidade - é responsável por um certo constrangimento, induzido em quem, nos dias que correm, se ocupa do estudo da poesia clássica greco-latina, cuja existência se funda por inteiro na observância estrita de metros inventariados e exaustivamente catalogados ao longo de mais de dois milênios de estudos. E forçoso procurar compreender o real papel da métrica na composição de poemas, se não pelo prestígio que o prêmio Nobel de Literatura de 1987 confere a sua crítica, pelo menos pela recorrência com que asserções desse mesmo naipe aparecem em poetas que exercem atividade crítica, como o Otávio Paz (1982) de O arco e a lira, ao afirmar categoricamente que metro e ritmo não são a mesma coisa. Esse artigo utiliza tais afirmações como ponto de partida para uma reflexão sobre o engendramento do ritmo e da poeticidade de versos em latim.

Influence of Platform and Abutment Angulation on Peri-Implant Bone. A Three-Dimensional Finite Element Stress Analysis

The aim of this study was to evaluate stress distribution on the pen-implant bone, simulating the influence of Nobel Select implants with straight or angulated abutments on regular and switching platform in the anterior maxilla, by means of 3-dimensional finite element analysis. Four mathematical models of a central incisor supported by external hexagon implant (13 mm x 5 mm) were created varying the platform (R, regular or S. switching) and the abutments (S, straight or A, angulated 15 degrees). The models were created by using Mimics 13 and Solid Works 2010 software programs. The numerical analysis was performed using ANSYS Workbench 10.0. Oblique forces (100 N) were applied to the palatine surface of the central incisor. The bone/implant interface was considered perfectly integrated. Maximum (sigma(max)) and minimum (sigma(min)) principal stress values were obtained. For the cortical bone the highest stress values (sigma(max)) were observed in the RA (regular platform and angulated abutment, 51 MPa), followed by SA (platform switching and angulated abutment, 44.8 MPa), RS (regular platform and straight abutment, 38.6 MPa) and SS (platform switching and straight abutment, 36.5 MPa). For the trabecular bone, the highest stress values (sigma(max)) were observed in the RA (6.55 MPa), followed by RS (5.88 MPa), SA (5.60 MPa), and SS (4.82 MPa). The regular platform generated higher stress in the cervical periimplant region on the cortical and trabecular bone than the platform switching, irrespective of the abutment used (straight or angulated).

Avaliação da resistência adesiva entre a superfície de uma cerâmica aluminizada e um cimento resinoso

Pós-graduação em Odontologia Restauradora - ICT

Avaliação da temperatura gerada e do tempo gasto durante o preparo do tecido ósseo com a utilização de brocas de diferentes sistemas de implantes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Valor de corte para teste respiratório com isótopos estáveis (Carbono 13) no diagnóstico do Helicobacter pylori utilizando IRMS para análise do sopro

After the isolation of Helicobacter pylori from an injury at the stomach mucosa by Marshall and Wareen, work that was recognized with the Nobel Prize of Medicine or Physiology in 2005, many other works showed the relationship between the presence of H. pylori and diseases at the digestive system, such as gastritis, gastric, duodenal and peptic ulcer, and stomach cancer. The 13C-Urea Breath Test - 13C-UBT is a non-invasive diagnostic method that utilizes the breath of a patient to determine the presence of H. pylori through stable isotopes. This work aimed to find an ideal 13C-UBT Isotopic Ratio Mass Spectroscopy cut-off value (a threshold between positive and negative) to diagnose H. pylori infection at Brazilian population. Patients were selected at the UNESP-Botucatu Clinical Hospital Endoscopy Section. With these results it was possible to indicate that the best cut-off value is between 2.5 to 6 ‰ of Delta Over Baseline (DOB)