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The goal was to evaluate the efficacy of the sausage technique in reconstructing the crestal buccal bone thickness, focusing on the distribution shape of the regenerated volume. Ten implants were placed in five patients with Cawood-Howell class IV defects. A cone beam computed tomography (CBCT) was executed at T0 (before surgery). Guided bone regeneration (GBR) with the sausage technique utilized a resorbable collagen membrane, made of a 50% autologous bone and a 50% anorganic bovine bone matrix (ABBM) mixture. After 6 months, a CBCT (T1) was performed before implant placement. Using CBCT software, a plane parallel to the implant axis intersected perpendicular planes every 1.5 mm from the crest level. T0 and T1 CBCT sections were analyzed, yielding 140 measurements. Statistical analysis via SPSS revealed a significant increase in thickness (average 2.82 ± 1.79 mm). Maximum gains occurred at 4.5 mm from the coronal crest line (3.8 ± 1.51 mm). The GBR sausage technique was effective with minimal post-operative complications, yielding the biggest gain at the mid-ridge sagittal area. Within the analysis limitations, it can be assumed that the sausage technique is effective for horizontal GBR in the maxilla, but a lesser volume might be achieved at the crestal level because it seems to follow a bowed regeneration shape.
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INTRODUCTION: Broken screw removal from the implant connection is a common but challenging process. Several proposed methods and technical solutions may result in unsuccessful removal; thus, a novel, more conservative, risk-free method is proposed as a first attempt. DESCRIPTION OF THE CASE: The proposal is to use a silicon restoration holder to be twisted counterclockwise on the dried surface of the broken fragment inside the implant connection. This method, within the limitations of a minimal case series, yielded 100% results; however, despite previous attempts with less con- servative techniques, this approach showed no efficacy. CONCLUSION: This article aims to promote the use of silicon restoration holders as a minimally invasive first attempt at broken screw retrieval treatment before considering other options.
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[This corrects the article DOI: 10.1371/journal.pone.0282748.].
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PURPOSE: There is growing interest in intelligent assistive technologies (IATs) in the rehabilitation and support of older adults, however, the factors contributing to or preventing their use in practice are not well understood. This study aimed to develop an overview of current knowledge on barriers and facilitators to the use of smart technologies in rehabilitative practice with older adults. MATERIALS AND METHODS: We undertook a scoping review following guidelines proposed by Arksey and O'Malley (2005) and Levac et al. (2010). A computerised literature search was conducted using the Scopus and Ovid databases, yielding 7995 citations. Of these, 94 studies met inclusion criteria. Analysis of extracted data identified themes which were explored in semi-structured interviews with a purposefully selected sample of seven clinical rehabilitation practitioners (three physical therapists, two occupational therapists, and two speech-language pathologists). RESULTS: Barriers and facilitators to using these technologies were associated with accessibility, reported effectiveness, usability, patient-centred considerations, and staff considerations. CONCLUSIONS: Collaborative efforts of policy-makers, researchers, manufacturers, rehabilitation professionals, and older persons are needed to improve the design of technologies, develop appropriate funding and reimbursement strategies, and minimise barriers to their appropriate use to support independence and quality of life. Any strategies to improve upon barriers to prescribing smart technologies for older people should leverage the expertise of rehabilitation professionals operating at the interface between older people; their health/mobility; their families; and technology-based solutions.Implications for rehabilitationThere is growing interest in intelligent assistive technologies (IATs) in the rehabilitation of older adults, as well as barriers to their use in practice.Rehabilitation professionals can play a key role in enabling access to IATs by recommending or prescribing their use to their older clients. Strategies to address barriers to the use of IATs for older people should leverage the expertise of rehabilitation professionals operating at the interface between older people, their families, and technology-based solutions.Older people and their families require technical support to initiate and continue to use IATs for rehabilitation. While rehabilitation providers may be well-placed to offer this support, they may require time and organizational support to build and maintain expertise in the fast-advancing field of smart technologies for rehabilitation.Cost and usability are universal challenges across the types of smart technologies considered in this review. Participatory approaches to involving older people in the design and development of smart assistive technologies contribute to better usability of these technologies. Devices and interventions that leverage more readily available devices and lower-cost components may overcome cost barriers to accessibility.
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Childhood obesity is a global public health concern linked to metabolic and psychological comorbidities. There is growing evidence that children's lifestyle habits are shifting towards obesity, with dire consequences for their future well-being and healthcare costs. In this interventional study, we enrolled 115 children aged between 4-5 years (53% females and 47% males) and carried out nutrition education interventions to improve their dietary habits. We introduced "Nutripiatto", a visual plate icon and easy guide, which was used by the children during the study. We investigated the children's dietary habits using a Food Frequency Questionnaire at the beginning and end of the study, after one month of using "Nutripiatto". The results showed that the children significantly increased the portion sizes and frequency of vegetable consumption (P<0.001) and reduced the consumption of several junk foods such as French fries and crisps (P<0.001), reaching the recommended dietary allowances and frequency of consumption. Daily consumption of water also significantly increased, reaching the suggested amount of six glasses per day. Based on these results, "Nutripiatto" can be considered an effective visual guide and helpful tool to achieve small changes and empower families to make healthier food choices. It can also be considered an effective educational tool for nutritionists and healthcare professionals to improve children's dietary behavior.
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Obesidade Infantil , Criança , Feminino , Masculino , Pré-Escolar , Humanos , Educação em Saúde , Escolaridade , Comportamento Alimentar , Inquéritos e QuestionáriosRESUMO
BACKGROUND: Integrating culturally competent approaches in the provision of health care services is recognized as a promising strategy for improving health outcomes for racially and ethnically diverse populations. Person-centered care, which ensures patient values guide care delivery, necessitates cultural competence of health care providers to reduce racial/ethnic health disparities. Previous work has focused on interventions to improve cultural competence among health care workers generally; however, little investigation has been undertaken regarding current practices focused on racialized foreign-born older adults. OBJECTIVE: We seek to synthesize evidence from existing literature in the field to gain a comprehensive understanding of interventions to improve the cultural competence of health professionals who care for racialized foreign-born older adults. The aim of this paper is to outline a protocol for a systematic review of available published evidence. METHODS: Our protocol will follow the PRISMA-P (Preferred Reporting Items for Systematic Reviews and Meta-Analyses-Protocols) for systematic review protocols. We will conduct a systematic search for relevant studies from four electronic databases that focus on health and social sciences (PubMed, CINAHL, Scopus, and Cochrane Database). After selecting relevant papers using the inclusion and exclusion criteria, data will be extracted, analyzed, and synthesized to yield recommendations for practice and for future research. RESULTS: The systematic review is currently at the search phase where authors are refining the search strings for the selected databases; the search strings will be finalized by July 2022. We anticipate the systematic review to be completed by December 2022. CONCLUSIONS: This study will inform the future development and implementation of interventions to support culturally competent, person-centered care of racialized foreign-born older adults. TRIAL REGISTRATION: PROSPERO CRD42021259979; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=259979. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/31691.
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OBJECTIVE: Efforts to describe the current state of research are needed to advance the field of physical-mental multimorbidity (ie, the co-occurrence of at least one physical illness and at least one mental disorder) among children and youth. Our objective was to systematically explore the breadth of physical-mental multimorbidity research in children and youth and to provide an overview of existing literature topics. DESIGN: Scoping review. METHODS: We conducted a systematic search of four key databases: PubMed, EMBASE, PsycINFO and Scopus as well as a thorough scan of relevant grey literature. We included studies of any research design, published in English, referring to physical-mental multimorbidity among children and youth aged ≤18 years. Studies were screened for eligibility and data were extracted, charted and summarised narratively by research focus. Critical appraisal was employed using the modified Quality Index (QI). RESULTS: We included 431 studies and 2 sources of grey literature. Existing research emphasises the co-occurrence of anxiety, mood and attention disorders among children with epilepsy, asthma and allergy. Evidence consists of mostly small, observational studies that use cross-sectional data. The average QI score across applicable studies was 9.1 (SD=1.8). CONCLUSIONS: There is a pressing need for more robust research within the field of child physical-mental multimorbidity.
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Multimorbidade , Transtornos Psicóticos , Adolescente , Ansiedade , Transtornos de Ansiedade , Criança , Estudos Transversais , HumanosRESUMO
(1) Objective: To longitudinally assess food and beverages sold in vending machines in secondary schools (grades 9-12) participating in the COMPASS study (2015/2016 and 2018/2019) and (2) to examine if patterns and trends observed in previous years (2012/2013 to 2014/2015) are consistent with lack of policy compliance in Ontario and Alberta, Canada. (2) Methods: Policy compliance was assessed through comparing nutritional information on drink (e.g., sports drinks) and snack (e.g., chocolate bars) products in vending machines to Policy and Program Memorandum (P/PM) 150 in Ontario (required policy) and the Alberta Nutrition Guidelines for Children and Youth (recommended policy). Longitudinal results and descriptive statistics were calculated. (3) Results: Longitudinal results indicate that between Y4 (2015/2016) and Y7 (2018/2019), snack and drink vending machines remained mostly non-compliant in Ontario and Alberta, with a small proportion of Ontario drink machines changing from non-compliant to compliant. At the school level, descriptive results indicate the proportion of Ontario schools with policy-compliant snack and drink machines decreased between Y4 and Y7. Alberta schools were non-compliant for drink and snack machines. (4) Conclusions: Secondary schools continue to be non-compliant with provincial policies. School nutrition policies need to be simplified in order to make it easier for schools to be compliant. Enforcement of compliancy is also an area that deserves consideration.
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Distribuidores Automáticos de Alimentos , Fidelidade a Diretrizes , Adolescente , Alberta , Bebidas , Criança , Seguimentos , Humanos , Política Nutricional , Ontário , Instituições AcadêmicasRESUMO
BACKGROUND: Endovascular therapy is the first-line strategy for femoropopliteal obstructive disease. However, for lesions involving the common femoral artery (CFA) surgical endarterectomy is still the gold standard. AIMS: The aim of this study was to evaluate the safety and efficacy of directional atherectomy (DA) for the treatment of CFA lesions. METHODS: A retrospective analysis of patients who underwent DA of the CFA between March 2009 and June 2017 was performed. The primary efficacy endpoint was the incidence of clinically driven target lesion revascularisation (cdTLR). Secondary endpoints included the overall procedural complication rate at 30 days, change in ankle-brachial index (ABI), and Rutherford-Becker class (RBC) during follow-up. RESULTS: This analysis included 250 patients. The mean follow-up period was 31.03±21.56 months (range 1-88, median follow-up period 25 months). The procedural complication rate including access-site complications, target lesion perforation, and outflow embolisation was 10.4% (n=26). All but one complication could be treated conservatively or endovascularly. One surgical revision was necessary. Freedom from major adverse events (death, cdTLR, myocardial infarction and major target limb amputation) at 30 days was 99.6%. The rate of cdTLR during follow-up was 13.6% (n=34). A significant improvement of the mean ABI and the RBC was observed. Multivariate logistic regression analysis revealed residual target lesion stenosis >30% (p=0.005), and heavy calcification of the target lesion (p=0.033) to be independent predictors for cdTLR. CONCLUSIONS: The use of DA for the treatment of CFA lesions leads to promising midterm results with an acceptable complication rate.
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Angioplastia com Balão , Doença Arterial Periférica , Aterectomia/efeitos adversos , Artéria Femoral/cirurgia , Humanos , Doença Arterial Periférica/cirurgia , Artéria Poplítea , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento , Grau de Desobstrução VascularRESUMO
Purpose: To assess the practical application and acute outcomes of the Tack Endovascular System for infrainguinal dissection repair in a real-world setting. Materials and Methods: Fifty-one consecutive patients who underwent endovascular revascularization for symptomatic peripheral artery disease and experienced 63 dissections requiring treatment were included in the prospective, single-center, single-arm study between January and June 2019. Thirty-nine (76.5%) lesions were ≥10 cm in length, 33 (64.7%) were totally occluded, and 13 (25.5%) were severely calcified. Fifty-six (88.9%) dissections were classified as severe. Dissections were treated either by means of the 6-F above-the-knee (ATK) or the 4-F below-the-knee (BTK) Tack Endovascular System. Observational outcomes were conditions and scopes of application. Clinical outcomes were acute technical and procedural success as well as safety. Results: Lesions were revascularized with 2.3±0.8 attempts such as standard balloon angioplasty, drug-coated balloon angioplasty, atherectomy, and/or lithotripsy. The Endovascular System was applied in 60 (95.2%) of 63 dissections. All dissections of the femoral artery were treated with the ATK system, and all infrapopliteal dissections with the BTK system. Both systems were successfully applied in popliteal artery dissections. Dissection length predicted the number of Tack implants deployed. Technical success was achieved in 98.3% (59 of 60 dissections). No major adverse event or device-related complication occurred during the procedure. Conclusion: Acute results in effectiveness and safety of the Tack Endovascular System for infrainguinal dissection repair in a real-world setting are promising.
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Procedimentos Endovasculares/instrumentação , Artéria Femoral/lesões , Doença Arterial Periférica/terapia , Artéria Poplítea/lesões , Próteses e Implantes , Calcificação Vascular/terapia , Lesões do Sistema Vascular/terapia , Ligas , Procedimentos Endovasculares/efeitos adversos , Artéria Femoral/diagnóstico por imagem , Artéria Femoral/fisiopatologia , Humanos , Doença Arterial Periférica/diagnóstico por imagem , Doença Arterial Periférica/fisiopatologia , Artéria Poplítea/diagnóstico por imagem , Artéria Poplítea/fisiopatologia , Estudos Prospectivos , Desenho de Prótese , Índice de Gravidade de Doença , Stents , Resultado do Tratamento , Turquia , Calcificação Vascular/diagnóstico por imagem , Calcificação Vascular/fisiopatologia , Grau de Desobstrução Vascular , Lesões do Sistema Vascular/diagnóstico por imagem , Lesões do Sistema Vascular/etiologia , Lesões do Sistema Vascular/fisiopatologiaRESUMO
O arroz irrigado é cultivado na maior parte do RS com aplainamento da superfície do solo em desnível e sistema de cultivo mínimo. Com a semeadura em solo seco, há necessidade de conformar drenos, que cortam transversalmente as taipas, na área de cultivo. Para o estabelecimento da lâmina de água definitiva, essas taipas abertas para drenagem devem ser fechadas e, para essa finalidade, não existe um equipamento específico que execute tal atividade com devida agilidade e qualidade, sendo necessário o desenvolvimento de um implemento com este fim. Ainda, para o processo de desenvolvimento de máquinas agrícolas, faz-se necessário o levantamento de uma série de informações. Na fase de projetação, essas informações são necessárias para o estabelecimento das necessidades dos clientes/usuários e dos requisitos dos clientes, para posteriormente serem transformadas em requisitos de projeto e estabelecidas as especificações de projeto. Desse modo, este trabalho objetivou determinar os requisitos dos clientes, a partir das suas necessidades, para o projeto de um implemento com a função de fechamento de taipas abertas para drenagem no arroz irrigado. As informações foram levantadas a partir de pesquisas bibliográficas e aplicação de questionários a futuros clientes/usuários. Como resultados, foram identificadas as necessidades dos clientes, assim como 25 requisitos de clientes.
The irrigated rice is grown on most part of RS with planning surface on sunken soil and minimum tillage system. With the dry soil sowing there is a need to conform drains, which cut across the levees in the growing area. For the establishment of a definitive water slide, these open for drainage levees must be closed and for this goal there is no specific equipment that execute such activity with agility and quality, being necessary the development of an implement. Still, for the agricultural machinery development process, the raising of a lot of information is required. At the design specification phase, this information is required for the constitution of the customer/users needs and requirements, in order to be transformed in design requirements and later establish the design specifications. Thereby, this study had the objective of determining the customer requirements, starting from customer needs, to design an implement for closure of open levees for drainage of irrigated rice. All the information was obtained from bibliographic research and questionnaire application to future customers/users. The customer needs, as well as, 25 customer requisites were identified as results.
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Tipicamente, a mandioca é comercializada na forma in natura, o que requer o descasque manual para posterior consumo humano. Atualmente, é crescente a comercialização da mandioca sem casca, pré-cozida e congelada, no entanto, o beneficiamento é realizado de forma artesanal. Este artigo trata do estudo da operação de retirada da casca e da entrecasca da mandioca, assim como dos demais fatores envolvidos, necessários à construção da base de conhecimentos requeridos para a definição conceitual da estrutura funcional, que expressa um equipamento a ser desenvolvido, destinado a este fim. Assim, o trabalho se delimita às fases iniciais do processo de projeto de produtos industriais. Nesse contexto, o objetivo é verificar se existe relação entre os fatores de influência na operação de descasque e a estrutura funcional de uma descascadora de mandioca. A metodologia empregada baseia-se no modelo de referência para o processo de desenvolvimento de máquinas agrícolas, com foco nas atividades concernentes às fases de projeto informacional e conceitual. Os resultados obtidos definem que a análise da operação de descasque, o conhecimento do sistema de cultivo e do processo operacional, as interferências e limites, os requisitos energéticos, o clima, ambiente e a planta são fatores de influência determinantes para a definição completa da estrutura funcional do equipamento. A função global "retirar a casca e a entrecasca da mandioca" se desdobra em quatro funções parciais, as quais decompõem-se em treze funções elementares. Destas, dez funções derivam-se diretamente dos fatores de influência identificados inicialmente. Com isso, verifica-se a existência de relação entre os fatores de influência no projeto e a estrutura funcional do descascador de mandioca, demonstrando dependência entre as definições feitas no início da fase de projeto informacional e as atividades da fase de projeto conceitual, responsáveis pela definição linguística do funcionamento do equipamento e de suas interdependências.
Cassava is marketed in fresh form, which requires manual peeling for later human consumption. Currently, there is a growing commercialization of peeled cassava, however the processing is done by hand. This article presents the study of the operation to remove the external shell and the inner shell of cassava, as well as others factors involved, necessary to build the knowledge base required for the conceptual definition of functional structure of a cassava peeling machine. This research is delimited to the early stages of the design of industrial products. The objective is to check whether there is a relationship between factors of influence in the operation of peeling and the functional structure of a cassava peeling machine. The methodology is based on a reference model for agricultural machinery development process, with a focus on activities pertaining to the phases of informational and conceptual design. The results establish that the analysis of the operation of peeling are determinants influencing factors for the complete definition of the functional structure. The global function "to remove the external shell and inner shell of cassava" consists in four partial functions that divide into thirteen elementary functions. Of these, ten functions are derived from the influence of the factors initially identified. Thus, it is possible to verify the existence of a relationship between the design influence factors and the functional structure of cassava peeling machine, demonstrating the dependence of the settings made in the informational design phase and the tasks established during the conceptual design phase.
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Our study concerns the effects of exposure to lead chloride on the morphology, K(+) efflux, SO(4)(-) influx and GSH levels of the human erythrocyte. Blood was collected in heparinized tubes and washed three times. The cells were suspended at 3% hematocrit and incubated for 1 h at 25°C in a medium containing increasing concentrations of lead chloride (0, 0.3, 0.5 and 1 µM). After incubation, the suspensions were centrifuged and the erythrocyte pellets were divided into three aliquots for testing. The results show: an increase in the permeability of erythrocytes treated with lead chloride with consequent damage and cellular death, especially in the presence of high concentrations; an increase in potassium ion efflux; alterations in the morphology and membrane structure of the red blood cells; and a decrease in sulphate uptake, due either to the oxidative effect of this compound on the band 3 protein, which loses its biological valence as a carrier of sulphate ions, or to a decrease in the ATP erythrocyte concentration. In conclusion, the exposure of erythrocytes to Pb(2+) ions leads to a reduction in the average lifetime of the erythrocytes and the subsequent development of anemia. These data are discussed in terms of the possible effect of lead on the reduction-oxidation systems of the cell. Oxidant agents, such as lead, are known to cross-link integral membrane proteins, leading to K/Cl-cotransport. The increased K(+) efflux affects the altered redox state.
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Membrana Eritrocítica/efeitos dos fármacos , Glutationa/metabolismo , Chumbo/toxicidade , Sulfatos/metabolismo , Trifosfato de Adenosina/metabolismo , Proteína 1 de Troca de Ânion do Eritrócito/metabolismo , Ânions/química , Apoptose/efeitos dos fármacos , Permeabilidade da Membrana Celular/efeitos dos fármacos , Membrana Eritrocítica/metabolismo , Humanos , Cinética , Oxirredução , Potássio/metabolismoRESUMO
O Brasil, terceiro maior produtor de biodiesel do mundo e terceiro maior produtor mundial de frango, pode incrementar, na sua matriz energética, o uso de óleo oriundo de aves como alternativa aos combustíveis fósseis e à redução da dependência do óleo de soja para esse fim. O país dispõe de mais de 350 milhões de litros de óleo de frango por ano. Considerando a aplicação dos combustíveis alternativos para os motores a diesel, em máquinas agrícolas, o trabalho teve por objetivo avaliar o desempenho do motor de um trator agrícola de 53kW acoplado pela TDP em bancada dinamométrica, operando com biodiesel metílico de óleo de frango e misturas com óleo diesel, sendo: B5 (testemunha), B20, B40, B60, B80 e B100. Avaliaram-se a potência, o torque, a reserva de torque, o consumo de combustível, o consumo de energia e a eficiência térmica do motor. O ensaio foi instalado com delineamento inteiramente casualizado (DIC) em esquema fatorial com seis tratamentos. Os resultados foram submetidos à análise de variância e as médias ajustadas por equações de regressão. Foram observadas perdas na geração de potência e torque, aumento no consumo de combustível, redução do consumo energético e melhoria na eficiência térmica do motor, de acordo com o aumento da proporção de biodiesel na mistura.
Brazil, the world third largest producer of biodiesel, and also the third largest producer of chicken, may increase the energy matrix, using oil derived from chicken, as an alternative to fossil fuels and reduce dependence on soybean oil for this purpose. The country can produce over 350 million liters of chicken oil per year. Considering the application of alternative fuels on diesel engines in agricultural machinery. The study aimed to evaluate the performance of a engine agricultural tractor with 53kW coupled by PTO in dynamometer bench operating with methyl biodiesel oil chicken and mix with diesel oil. Fuels B5 (reference), B20, B40, B60, B80 and B100 mixtures were used. The power, torque, torque reserve, fuel consumption, energy consumption and thermal efficiency of the engine were evaluated. The trial was conducted with a completely random design (CRD) in a factorial design with six treatment, which was held after the analysis of variance and adjusted means for the regression equations. Losses were observed in the generation of power and torque, increase in fuel consumption, reduction of energy consumption and improvement in engine thermal efficiency, according to the increasing proportion of biodiesel in the blend.
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Considerando que o Brasil detém uma vasta gama de matérias-primas para produção de biodiesel, e também que há a possibilidade de produção em pequena escala, prima-se por estudos de cunho econômico a partir de metodologias de fácil execução. O objetivo do trabalho foi demonstrar uma metodologia e sua aplicação para avaliação dos custos inseridos dentro do processo produtivo e de utilização do biodiesel. A metodologia foi aplicada a biodieseis originários de óleo de soja, girassol, frango e sebo bovino, dos quais se avaliaram economicamente os custos fixos e variáveis para conversão química dos óleos e gorduras em ésteres metílicos, em uma planta de produção experimental. Os custos de produção para cada uma das quatro citadas são distintos em função do valor inicial por litro de cada uma. Também fora avaliado o custo específico e o consumo específico de cada um dos biodieseis, a fim de determinar a diferença em relação ao óleo diesel comercial. No estudo de caso, os resultados mostraram vantagens para o óleo diesel, tanto no custo quanto no consumo. Comparando-se os biodieseis, o de sebo bovino apresentou-se com o menor custo de produção e o menor consumo.
Considering that Brazil has a wide range of raw materials for biodiesel production, and also the possibility of small scale production, there is a demand for economic methodology studies with easy implementation. The objective of this research was to demonstrate a methodology and its application to assess the costs within the production process and the biodiesel use. The methodology was applied to biodiesels originated from soybean oil, sunflower oil, chicken oil and beef tallow, which assessed the fixed and variable costs for chemical conversion of oils and fats into methyl esters in an experimental production plant. Production costs for each of the four mentioned esters are peculiar due to the initial value of each oil per liter. Also the specific cost and specific fuel consumption were evaluated for each biodiesel to determine the difference with the commercial diesel oil. The case study showed advantages for diesel oil, both in cost and consumption. Comparing the biodiesels, the beef tallow showed the lowest production costs and lower consumption.
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The objective of this study was to assess the effects of nickel chloride on human and rainbow trout erythrocytes in vitro. The cells were incubated with 0, 0.5 and 1 mM nickel chloride for 1 h at pH 7.40 and 25 degrees C, then K(+) efflux, SO (4) (2-) uptake and GSH and GSSG concentrations were measured. In both kind of cells, "high concentration" nickel treatment increased KCl efflux with respect to the control. The SO (4) (2-) uptake was not significantly different at "low nickel concentration" but was lower in erythrocytes treated with 1 mM nickel chloride; the rate constant of SO (4) (2-) uptake decreased by 35% in human erythrocytes and by 44% in fish erythrocytes. Nickel chloride also acts on cellular metabolism and in particular on erythrocyte glutathione peroxidase with consequent increase in oxidative stress; the data show a significant decrease in intracellular GSH in both human (25%) and fish erythrocytes (18%) after treatment with nickel chloride, with concomitantly high GSSG concentrations and lower GSH/GSSG ratios.
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Proteína 1 de Troca de Ânion do Eritrócito/metabolismo , Eritrócitos/efeitos dos fármacos , Níquel/farmacologia , Animais , Tamanho Celular , Glutationa/sangue , Humanos , Oncorhynchus mykiss , Oxirredução , Estresse Oxidativo , Potássio/metabolismo , Sulfatos/metabolismoRESUMO
BACKGROUND/AIMS: The erythrocyte is a cell exposed to a high level of oxygen pressure and to oxidative chemical agents. This stress involves SH-groups oxidation, cell shrinkage by activation of K-Cl co-transport (KCC) and elevation of the band 3 tyrosine phosphorylation level. The aim of our study was to test whether oxidative stress could influence band 3-mediated anion transport in human red blood cells. METHODS: To evaluate this hypothesis, normal and pathological (glucose 6 phosphate dehydrogenase (G6PDH) defficient) erythrocytes were treated with known sulphydryl-blocking or thiol-oxidizing agents, such as N-ethylmaleimide (NEM), azodicarboxylic acid bis[dimethylamide] (diamide), orthovanadate, Mg2+ and tested for sulphate (SO4-) uptake, K+ efflux, G6PDH activity and glutathione (GSH) concentration. RESULTS: In normal red blood cells, the rate constants of SO4- uptake decreased by about 28 % when cells were incubated with NEM, diamide and orthovanadate. In G6PDH-deficient red blood cells, in which oxidative stress occurs naturally, the rate constant of sulphate uptake was decreased by about 40% that of normal red cells. Addition of oxidizing and phosphatase inhibitor agents to pathological erythrocytes further decreased anion transport. In contrast, G6PDH activity was increased under oxidative stress in normal as well as in pathological cells and was lower in the presence of exogenous Mg2+ in parallel to a significant increase in sulphate transport. In both cells, the oxidizing agents increased K+ efflux with depletion of GSH. CONCLUSION: The data are discussed in light of the possible opposite effects exerted by oxidative agents and Mg2+ on KCC and on the protein tyrosine kinase (PTK)-protein tyrosine phosphatase (PTP) equilibrium. The decreased sulphate uptake observed in the experimental and pathological conditions could be due to band 3 SH-groups oxidation or to oxidative stress-induced K-Cl symport-mediated cell shrinkage with concomitant band 3 tyrosine phosphorylation.
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Proteína 1 de Troca de Ânion do Eritrócito/metabolismo , Eritrócitos/metabolismo , Proteína 1 de Troca de Ânion do Eritrócito/química , Tamanho Celular , Cloretos/sangue , Eritrócitos/citologia , Eritrócitos/efeitos dos fármacos , Deficiência de Glucosefosfato Desidrogenase/sangue , Glutationa/sangue , Humanos , Técnicas In Vitro , Transporte de Íons/efeitos dos fármacos , Magnésio/farmacologia , Oxidantes/farmacologia , Estresse Oxidativo , Fosforilação , Potássio/sangue , Sulfatos/sangue , Compostos de Sulfidrila/química , Reagentes de Sulfidrila/farmacologia , Simportadores/sangue , Simportadores/química , Cotransportadores de K e Cl-RESUMO
Sulfate transport by band-3 protein in adult human erythrocytes was shown to be modulated by oxygen pressure. In particular, a higher transport activity was measured under high oxygen pressure than at low one (0.0242+/-0.0073 vs. 0.0074+/-0.0010 min(-1)). Other factors, such as magnesium ions and orthovanadate, which can indirectly affect the binding properties of the cytoplasmic domain of band 3 (cdb3), influence significantly the anion exchanger activity. No effect of oxygen pressure on sulfate transport was found in chicken erythrocytes, which may be related to their lacking the cdb3 binding site. These findings are fully consistent with a molecular mechanism where the oxygen-linked transition of hemoglobin (T-->R) could play a key role in the regulation of anion exchanger activity.