63 resultados para Ácidos graxos de cadeia longa
Resumo:
Diversion colitis is a chronic inflammatory process affecting the dysfunctional colon, after a colostomy. It is postulated that nutritional deficiency of the colonic epithelium by the absence of short-chain fatty acids (SCFA) is one of the factors responsible for the appearance of DC and that their employment could reverse the morphological changes of the mucosa. The treatment of choice for fecal diversion colitis (DC) is the reconstruction of the intestinal tract, although they suggested therapeutic options using enemas. This study evaluates the effect of SCFA in atrophy and inflammation in excluded colonic segments before and after the installation DC. Forty Wistar rats were divided into four groups (n = 10 for each group), submitted colostomy with distal colon exclusion. Two control groups (A1 and B1) received rectally administered physiological saline, whereas two experimental groups (A2 and B2) received rectally administered short-chain fatty-acids. The A groups were prophylactically treated (5th to 40th days postoperatively), whereas the B groups were therapeutically treated (after postoperative day 40), for 07 days. Histological sections stained with HE were used for histological analysis of the thickness of the colonic mucosa excluded (t- Student p ≤0.05). Inflammatory reaction of the lamina propria and mucosa were measured with scores previously established (Mann Whitney p ≤ 0.05). There was a significant thickness recovery of the colonic mucosa in group B2 animals (p = 0.0001), which also exhibited a significant reduction in the number of eosinophilic polymorphonuclear cells in the lamina propria (p = 0.0126) and in the intestinal lumen (p = 0.0256). Group A2 did not prevent the mucosal atrophy and significant increases in the numbers of lymphocytes (p=0.0006) and 50 eosinophilic polymorphonuclear cells in the lamina propria of the mucosa (p = 0.0022). Therapeutic use of short-chain fatty-acids significantly reduced eosinophilic polymorphonuclear cell numbers in the intestinal wall and in the colonic lumen; it also reversed the atrophy of the colonic mucosa. Prophylactic use did not impede the development of mucosal atrophy
Resumo:
The biodiesel is defined as the mono-alkyl ester derived from long-chain fatty acids, from renewable sources such as vegetable oils or animal fat, whose use is associated with the replacement of fossil fuels in diesel engine cycle. The biodiesel is susceptible to oxidation when exposed to air and this process of oxidation affects the quality of fuel, mainly due to long periods of storage. Because of this, the oxidation stability has been the focus of numerous researches since it directly affects the producers, distributors and users of fuel. One of the possibilities to increase the resistance of biodiesel is the autoxidation treatment with inhibitors of oxidation. The antioxidants can be used as potential inhibitors of the effects of oxidation on the kinematic viscosity and the index of acidity of biodiesel, thereby increasing oxidative stability. This work aims to examine the efficiency of antioxidants, α-tocopherol and butylated hydroxy-toluene (BHT), added the biodiesel content of remembrance through Pressurized-Differential Scanning Calorimetry (P-DSC), Thermogravimetry (TG) and Petrology. The results showed that the use of antioxidant BHT, at the concentration of 2000ppm, increased resistance to oxidation of the biodiesel and oxidative induction time (OIT), which is a better result as antioxidant than the α-tocopherol. With the thermogravimetric analysis, it was observed that the biodiesel presented an initial decomposition temperature of lower tendency than that of oil, demonstrating to be more volatile, bearing great similarity to the diesel and being characterized as an alternative fuel. The rheological analysis indicated that each sample of biodiesel behaved as a Newtonian fluid
Resumo:
Corrosion usually occurs in pipelines, so that it is necessary to develop new surface treatments to control it. Surfactants have played an outstanding role in this field due to its capacity of adsorbing on metal surfaces, resulting in interfaces with structures that protect the metal at low surfactant concentrations. The appearance of new surfactants is a contribution to the area, as they increase the possibility of corrosion control at specific conditions that a particular oil field presents. The aim of this work is to synthesize the surfactants sodium 12 hydroxyocadecenoate (SAR), sodium 9,10-epoxy-12 hydroxyocadecanoate (SEAR), and sodium 9,10:12,13-diepoxy-octadecanoate (SEAL) and apply them as corrosion inhibitors, studying their action in environments with different salinities and at different temperatures. The conditions used in this work were chosen in order to reproduce oil field reality. The study of the micellization of these surfactants in the liquid-gas interface was carried out using surface tensiometry. It was observed that cmc increased as salt concentration was increased, and temperature and pH were decreased, while cmc decreased with the addition of two epoxy groups in the molecule. Using the values of cmc and the Gibbs equation, the values of Gibbs free energy of adsorption, area per adsorbed molecule, and surface excess were calculated. The surface excess increases as salt concentration and temperature decreases, increasing as pH is increased. The area per adsorbed molecule and the free energy of adsorption decrease with salt concentration, temperature, and pH increase. SAXS results showed that the addition of epoxy group in surfactant structure results in a decrease in the repulsion between the micelles, favoring the formation of more oblong micellar structures, ensuring a better efficiency of metal coverage. The increase in salt and surfactant concentrations provides an increase in micellar diameter. It was shown that the increase in temperature does not influence micellar structure, indicating thermal stability that is advantageous for use as corrosion inhibitor. The results of inhibition efficiency for the surfactants SEAR and SEAL were considered the best ones. Above cmc, adsorption occurred by the migration of micelles from the bulk of the solution to the metal surface, while at concentrations below cmc film formation must be due to the adsorption of semi-micellar and monomeric structures, certainly due to the presence of the epoxy group, which allows side interactions of the molecule with the metal surface. The metal resistance to corrosion presented values of 90% of efficiency. The application of Langmuir and Frumkin isotherms showed that the later gives a better description of adsorption because the model takes into account side interactions from the adsorbing molecules. Wettability results showed that micelle formation on the solid surface occurs at concentrations in the magnitude of 10-3 M, which isthe value found in the cmc study. This value also justifies the maximum efficiencies obtained for the measurements of corrosion resistance at this concentration. The values of contact angle as a function of time suggest that adsorption increases with time, due to the formation of micellar structures on metal surface
Resumo:
The objective of this research was to evaluate the influence of the supply of five types of native and exotic cacti Brazilian semiarid northeast on the sensory characteristics of milk of Saanen goats. Five multiparous goats were used with nine weeks of lactation, average live weight of 50 kg ± 4 kg., confined and distributed in a Latin square design 5 x 5 with five experimental diets and five periods. Each period lasted 17 days, with 10 days of adaptation to the diets of the animals and seven days for the data collection. The treatments were defined based on dry matter consisted of: 47.33 to 50.12% of a cactus (“Xiquexique”, “Mandacaru”, “Facheiro” or two species of forage cactus “Miúda” or “Orelha de Elefante Mexicana”) more 18.78 to 19.79% hay of plant “Sabiá” and 31.10 to 32.89% of concentrate. There was not effect of the experimental diets in the physical and chemical composition of milk for fat, total solids and salts, which showed mean values of 3.24%; 11.30% and 0.66%, respectively. However the protein, lactose, nonfat dry extract and freezing point were affected by diets. In the profile of fatty acids was higher concentration of fatty short and medium chain fatty acids, however, there were not changes between treatments, except for the butyric acid (C4:0), with mean values of 4.24% (“Orelha de Elefante Mexicana”) to 6.05% (“Facheiro”). The diets also did not provide sensory changes in milk for the parameters: odor, flavor, aftertaste and overall assessment. The use of the five cactus in the diet of dairy goats do not influence the sensory characteristics and lipid profile of milk. The physical and chemical composition of milk was showed within the minimum requirements of current legislation, except for nonfat dry extract and freezing point.
Resumo:
Provide healthier meat to consumers of pig farmers has required an adjustment of nutrition and feed management. Nutrition is a primary factor in defining the qualitative aspects of pork, because through it we can modify the fatty acid profile. The objective of this study was to analyze the effects of adding bran bagasse cashew (FBC) in diets for finishing pigs, on carcass traits and meat quality. 20 crossbred barrows with an average initial weight of 57.93 ± 3.67 kg / BW were used Diets were formulated based on corn and soybean meal containing vegetable oil, commercial core and different levels of inclusion of the bran bagasse cashew ( 0.0, 7.5 % , 15.0 % , 22.5 % and 30.0 % ) . The experimental design was a randomized block with 5 treatments and 4 replications. Quantitative, qualitative, fatty acid profile of the longissimus muscle and fat area parameters were evaluated. It was observed that with the inclusion of FBC, the parameters of carcass yield, backfat thickness, fat area had a negative linear effect relationship and meat / fat positive effect. Regarding the profile of fatty acids in fat area, the content of linoleic fatty acid level of 30 % of FBC was 18.2 % higher ( P < 0.05 ) at the level of 0.0 % and the arachidonic level of 22.5 % was higher than 33.3 % and 37.5 % at levels of 0.0 % and 15.0 % ( FBC ) respectively. It is concluded that finishing pigs may be food diets containing up to 30 % of FBC, improving the quality of housing for lower fat deposition and modification in the fatty acid profile.
Resumo:
A colite de derivação fecal (CD) é um processo inflamatório que ocorre no segmento colorretal desfuncionalizado, após uma cirurgia de desvio do trânsito intestinal. As principais características dessa entidade clínica são: apresenta-se na desfuncionalização do cólon ou reto; não há doença inflamatória intestinal preexistente; nunca acomete o sítio proximal à colostomia e ocorre resolução do processo após a restauração do trânsito intestinal. Diversas são as hipóteses postuladas para explicar o seu aparecimento; todavia, a deficiência nutricional do epitélio colônico, pela ausência dos ácidos graxos de cadeia curta (AGCC), no segmento desfuncionalizado, é a mais aceita na atualidade. Os autores fazem uma revisão da literatura enfocando os aspectos clínicos, histopatológicos e terapêuticos desta doença
Resumo:
A colite de derivação fecal (CD) é um processo inflamatório que ocorre no segmento colorretal desfuncionalizado, após uma cirurgia de desvio do trânsito intestinal. As principais características dessa entidade clínica são: apresenta-se na desfuncionalização do cólon ou reto; não há doença inflamatória intestinal preexistente; nunca acomete o sítio proximal à colostomia e ocorre resolução do processo após a restauração do trânsito intestinal. Diversas são as hipóteses postuladas para explicar o seu aparecimento; todavia, a deficiência nutricional do epitélio colônico, pela ausência dos ácidos graxos de cadeia curta (AGCC), no segmento desfuncionalizado, é a mais aceita na atualidade. Os autores fazem uma revisão da literatura enfocando os aspectos clínicos, histopatológicos e terapêuticos desta doença
Resumo:
The growing utilization of surfactants in several different areas of industry has led to an increase on the studies involving solutions containing this type of molecules. Due to its amphiphilic nature, its molecule presents one polar part and one nonpolar end, which easily interacts with other molecules, being able to modify the media properties. When the concentration in which its monomers are saturated, the airliquid system interface is reached, causing a decrease in interfacial tension. The surfactants from pure fatty acids containing C8, C12 and C16 carbonic chains were synthesized in an alcoholic media using sodium hydroxide. They were characterized via thermal analysis (DTA and DTG) and via infrared spectroscopy, with the intention of observing their purity. Physical and chemical properties such as superficial tension, critical micelle concentration (c.m.c), surfactant excess on surface and Gibbs free energy of micellization were determined in order to understand the behaviour of these molecules with an aqueous media. Pseudo-ternary phase diagrams were obtained aiming to limit the Windsor equilibria conditions so it could be possible to understand how the surfactants carbonic chain size contributes to the microemulsion region. Solutions with known concentrations were prepared to study how the surfactants can influence the dynamic light scattering spectroscopy (DLS) and how the diffusion coefficient is influenced when the media concentration is altered. The results showed the variation on the chain size of the studied surfactant lipophilic part allows the conception of surfactants with similar interfacial properties, but dependent on the size of the lipophilic part of the surfactant. This variation causes the surfactant to have less tendency of microemulsionate oil in water. Another observed result is that the n-alcanes molecule size promoted a decrease on the microemulsion region on the obtained phase diagrams
Resumo:
The aim of this work was the preparation of polyols from reactions between castor oil and dietanolamine to increase the hydroxyl content and the network degree in the products to application in electronic devices. The polyols and the mixtures obtained were characterized by nuclear magnetic ressonance. Castor oil (CO) is a natural triglyceride - based polyol possessing hydroxyl groups, which allow several reactions that produce many different products. Among them are the polyurethanes (PU), which have been considered an ideal product for the covering of electricelectronic circuits, due to their excellent electrical, shock-absorbing, solvents resistance and hydrolytic stability properties. About 90% of the fatty acids present in the castor oil are ricinoleic acid (12-hydroxyoleic acid), while the remaining 10% correspond to non-hydroxylated fatty acids, mainly linoleic and oleic acids. The chemical analysis of castor oil indicates a hydroxyl number of 2.7. In this work, a polyol was obtained by the reaction of the CO with diethanolamine (DEA), in order to elevate the hydroxyl value from 160 to 230 or to 280 mgKOH/g, and characterized by nuclear magnetic resonance (NMR) 1H and 13C (Mercury 200). The polyadition of the resulting polyol with isophorone diisocianate (IPDI) was carried out at 60°C, and the reaction kinetics was followed by rheological measurements in a Haake RS150 rheometer. The electrical properties were determined in a HP LCR Meter 4262A, at 1.0 Hz and 10.0 KHz. The chemical analysis showed that the polyols obtained presented hydroxyl number from 230 to 280 mgKOH/g. The polyadition reaction with IPDI produced polyurethane resins with the following properties: hardness in the range from 45 shore A to 65 shore D (ASTM D2240); a dielectric constant of 3.0, at 25°C (ASTM D150). Those results indicate that the obtained resins present compatible properties to the similar products of fossil origin, which are used nowadays for covering electric-electronic circuits. Therefore, the PUs from castor oil can be considered as alternative materials of renewable source, free from the highly harmful petroleum - derived solvents
Resumo:
Recently, marine organisms have attracted attention because of the complexity and potent biological activity from your secondary metabolites. Our planet has 80% it surface covered by oceans and seas, therefore, housing a wide number of different forms of life, among them, the sponges. These sessile and filtrating animals, according to numerous researches, come showing like true chemistry factories. The substances from these animals, sometimes show as news targets to therapeutics agents, and some countries has already use them for treatment of some diseases. Further of the secondary metabolites, the polysaccharides of marine origin also have been target of studies, because the presence of the sulfates groups in its molecules. Polysaccharides with differents biological activities have been related in a large number of researches. Actually, many studies show the sponges as source of promising medicine. These studies inspire new researches, because the few number of sponges species studied until now. Because of that, the present work shows the chemistry prospection of the sponge Callyspongia vaginalis. Chromatographic methods in silica gel allowed the isolations of two secondary metabolites: the known β- sitosterol and a ceramide, no reported in the genus Callyspongia, previously. The analysis of the their lipid extracts show different kinds of fatty acids with a variety of chain length (saponifiable fraction), and others metabolites like Lupenone and stigmasterol, also unprecedented in the genus. The Polysaccharide characterization and the elucidation of the secondary metabolites acquired through of chromatography analysis (CC, molecular exclusion) and spectrometric (NMR 1H and 13C, mass, IR), respectively and comparison with literature data
Estudo teórico de intermediários tetraédricos acidez / basicidade e estereosseletividade enzimáticos
Resumo:
The present work aimed first, the theoretical study of tetrahedral intermediate stability formed from carbonyl addition reactions using the second (MP2) and third (MP3) order Møller–Plesset perturbation theory. Linear correlations between electronic energy difference of reactions with Wiberg Indexes and C-O bond lengths were obtained, and was observed that the stability of adducts formed depends directly of electronic density involved between these atoms. The knowing of electronic parameters of these structures has an important hole due to the large use on reactions that in his course forms this tetrahedral intermediate. Employing the ONIOM (B3LYP:AMBER) methodology, was evaluated the stereoselectivity of a enzymatic reaction between CAL B enzyme and a long chain ester. In this study, were obtained the electronic energies of ground state and intermediate state of transesterification rate-determing step from two possible proquirals faces Re and Si. The objective was study the enantioselectivity of CAL B and rationalizes it using quantum theory of atoms in molecules (QTAIM). A theoretical study employing inorganic compounds was performed using ab initio CBS-QB3 method aiming to find a link between thermodynamic and equilibrium involving acids and bases. The results observed showed an excellent relationship between difference in Gibbs free energy, ΔG of acid dissociation reaction and ΔG of hydrolysis reaction of the corresponding conjugate base. It was also observed, a relationship between ΔG of hydrolysis reaction of conjugate acids and their corresponding atomic radius showing that stability plays an important role in hydrolysis reactions. The importance of solvation in acid/base behavior when compared to theoretical and experimental ΔG´s also was evaluated.
Resumo:
Analisar a atuação dos enfermeiros de unidade de terapia intensiva na prevenção da úlcera por pressão. Método: trata-se de estudo descritivo desenvolvido com 13 enfermeiros da unidade de terapia intensiva do Hospital Universitário Onofre Lopes (HUOL), em Natal-RN. Foi aplicado um questionário, submetido à análise de conteúdo temática. O estudo foi aprovado pelo Comitê de Ética da Universidade Federal do Rio Grande do Norte (UFRN), sob o CAAE n. 0240.0.051.000-10. Resultados: os enfermeiros reportaram a realização da mudança de decúbito, a avaliação de risco, a discussão com os colegas sobre as medidas adotadas, a higiene e hidratação da pele do paciente através de uso de ácidos graxos essenciais e hidratante corporal, o cuidado com a disposição dos lençóis, de forma a evitar dobras, a utilização de colchão de ar e a aplicação de placas de hidrocoloide nas proeminências ósseas. Conclusão: a prática da prevenção das úlceras por pressão aplicada pelos enfermeiros da unidade de terapia intensiva ocorre sem padronização dos cuidados
Resumo:
The β-proteobacterium Chromobacterium violaceum is a Gram-negative, free-living, saprophytic and opportunistic pathogen that inhabits tropical and subtropical ecosystems among them, in soil and water of the Amazon. It has great biotechnological potential, and because of this potential, its genome was completely sequenced in 2003. Genome analysis showed that this bacterium has several genes with functions related to the ability to survive under different kinds of environmental stresses. In order to understand the physiological response of C. violaceum under oxidative stress, we applied the tool of shotgun proteomics. Thus, colonies of C. violaceum ATCC 12472 were grown in the presence and absence of 8 mM H2O2 for two hours, total proteins were extracted from bacteria, subjected to SDS-PAGE, stained and hydrolysed. The tryptic peptides generated were subjected to a linear-liquid chromatography (LC) followed by mass spectrometer (LTQ-XL-Orbitrap) to obtain quantitative and qualitative data. A shotgun proteomics allows to compare directly in complex samples, differential expression of proteins and found that in C. Violaceum, 131 proteins are expressed exclusively in the control condition, 177 proteins began to be expressed under oxidative stress and 1175 proteins have expression in both conditions. The results showed that, under the condition of oxidative stress, this bacterium changes its metabolism by increasing the expression of proteins capable of combating oxidative stress and decreasing the expression of proteins related processes bacterial growth and catabolism (transcription, translation, carbon metabolism and fatty acids). A tool with of proteomics as an approach of integrative biology provided an overview of the metabolic pathways involved in the response of C. violaceum to oxidative stress, as well as significantly amplified understanding physiological response to environmental stress. Biochemical and "in silico" assays with the hypothetical ORF CV_0868 found that this is part of an operon. Phylogenetic analysis of superoxide dismutase, protein belonging to the operon also showed that the gene is duplicated in genome of C. violaceum and the second copy was acquired through a horizontal transfer event. Possibly, not only the SOD gene but also all genes comprising this operon were obtained in the same manner. It was concluded that C. violaceum has complex, efficient and versatile mechanisms in oxidative stress response
Resumo:
Biodiesel is a fuel obtained from vegetable oils, such as soy, castorbean, among others. The monoester of fatty acid of these oils have chains with mono, di and tri double connections. The presence of these insaturations are susceptible to oxidization. Antioxidants are substances able to prevent oxidization from oils, fats, fat foods, as well as esters of Alquila( biodiesel). The objective of this work is to summarize a new antioxidant from the Cashew Nut Shell Liquid (CNSL) using the electrolysis technique. A current of 2 amperes was used in a single cell of only one group and two eletrodos of stainless steel 304 in a solution of methanol, together with the eletrolits: acetic acid, sodium chloride and sodium hydroxide, for two hours of agitation. The electrolysis products are characterized by the techniques of cromatography in a thin layer, spectroscopy of infrared and gravimetric analysis. The material was submitted to tests of oxidative stability made by the techniques of spectropy of impendancy and Rancimat (EN 14112). The analyses of characterization suggest that the polimerization of the electrolytic material ocurred. The application results of these materials as antioxidants of soy biodiesel showed that the order of the oxidative stability was obtained by both techniques used
Resumo:
Biodiesel is an alternative fuel, renewable, biodegradable and nontoxic. The transesterification of vegetable oils or animal fat with alcohol is most common form of production of this fuel. The procedure for production of biodiesel occurs most commonly through the transesterification reaction in which catalysts are used to accelerate and increase their income and may be basic, acid or enzyme. The use of homogeneous catalysis requires specific conditions and purification steps of the reaction products (alkyl ester and glycerol) and removal of the catalyst at the end of the reaction. As an alternative to improve the yield of the transesterification reaction, minimize the cost of production is that many studies are being conducted with the application of heterogeneous catalysis. The use of nano-structured materials as catalysts in the production of biodiesel is a biofuel alternative for a similar to mineral diesel. Although slower, can esterify transesterified triglycerides and free fatty acids and suffer little influence of water, which may be present in the raw material. This study aimed at the synthesis, characterization and application of nano-structured materials as catalysts in the transesterification reaction of soybean oil to produce biodiesel by ethylic route. The type material containing SBA-15 mesoporous lanthanum embedded within rightly Si / La = 50 was used catalyst. Solid samples were characterized by X-ray diffraction, thermogravimetric analysis, infrared spectroscopy, nitrogen adsorption and desorption. For the transesterification process, we used a molar ratio of 20:1 alcohol and oil with 0.250 g of catalyst at 60°C and times of 6 hours of reaction. It was determined the content of ethyl esters by H-NMR analysis and gas chromatography. It was found that the variable of conversion obtained was 80%, showing a good catalytic activity LaSBA-15 in the transesterification of vegetable oils via ethylic route