Últimos itens adicionados do Acervo: Universidade Federal dos Vales do Jequitinhonha e Mucuri

A Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM) é uma universidade pública brasileira sediada na cidade de Diamantina, estado de Minas Gerais, no Brasil. Foi criada em 6 de setembro de 2005.

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‣ Esse ? um Teste

Fonte: Universidade Federal dos Vales do Jequitinhonha e Mucuri Publicador: Universidade Federal dos Vales do Jequitinhonha e Mucuri
Tipo: Artigo de Revista Científica
Português

‣ Teste; Teste

Teste, Teste
Fonte: Universidade Federal dos Vales do Jequitinhonha e Mucuri Publicador: Universidade Federal dos Vales do Jequitinhonha e Mucuri
Tipo: Dissertação de Mestrado Formato: Teste
Português
Teste; Teste; Teste; Teste

‣ Efeitos da restri??o cal?rica desde o nascimento sobre o cora??o de ratos adultos

Melo, Dirceu de Sousa
Fonte: Universidade Federal dos Vales do Jequitinhonha e Mucuri Publicador: Universidade Federal dos Vales do Jequitinhonha e Mucuri
Tipo: Dissertação de Mestrado
Português
Evid?ncias recentes sugerem que a restri??o cal?rica intensa (RCI) (>40%) exerce efeitos ben?ficos sobre o cora??o de ratos. No entanto, a maioria destes estudos avaliaram os efeitos da RCI em cora??es de ratos que iniciaram esta restri??o j? na idade adulta. Neste trabalho, investigamos as conseq??ncias de uma restri??o cal?rica de 50% desde o nascimento sobre a fun??o e morfologia card?aca de ratos adultos e avaliamos os poss?veis mecanismos envolvidos nestas adapta??es. Desde o nascimento at? a idade de 90 dias ratos RC50 tiveram sua alimenta??o restrita a 50% do consumo do grupo ad libitum (AL). Durante o per?odo de 90 dias os animais tiveram sua ingest?o alimentar, peso corporal e press?o arterial monitorados. Ap?s este per?odo, foi realizado um teste de capacidade aer?bica m?xima para avaliar indiretamente a fun??o cardiovascular global. Quarenta e oito horas ap?s este teste os animais foram eutanasiados, o sangue foi coletado para an?lise do hemat?crito, bioqu?mica s?rica e estresse oxidativo e o m?sculo s?leo retirado para an?lise do estresse oxidativo. A t?bia foi retirada para aferi??o do comprimento e f?gado, ba?o, supra-renais, test?culos e gordura viceral removidos para aferi??o do peso. O cora??o foi retirado e o ?ndice de desenvolvimento de tens?o m?xima (+dT/dt) e m?nima (-dT/dt) do mioc?rdio foram analisados pela prepara??o de cora??o isolado. Tamb?m foi realizada an?lise do estresse oxidativo card?aco e o di?metro...

‣ vbv

Fonte: Universidade Federal dos Vales do Jequitinhonha e Mucuri Publicador: Universidade Federal dos Vales do Jequitinhonha e Mucuri
Português
vbvbv

‣ gvbcvbv; cvbcvb

vbcvb, bcbfbvc
Fonte: UFVJM Publicador: UFVJM
Formato: xcxcx
Português
dcds; cxcx; xcxc; Tese (Doutorado em Ci?ncias Fisiol?gicas) ? Programa Multic?ntrico de P?s-gradua??o em Ci?ncias Fisiol?gicas, Universidade Federal dos Vales do Jequitinhonha e Mucuri, ano de defesa.

‣ Determina??o simult?nea de catecol e hidroquinona empregando um sensor seletivo ? base de ftalocianina de mangan?s e nanotubos de carbono

Silva, Saimon Moraes
Fonte: UFVJM Publicador: UFVJM
Tipo: Dissertação de Mestrado
Português
?rea de concentra??o: Qu?mica Anal?tica; ABSTRACT The present work describes the development of a selective and sensitive voltammetric sensor for catechol (CC) and hydroquinone (HQ) using a glassy carbon (GC) electrode modified with manganese phthalocyanine (MnPc) adsorbed on multiwalled carbon nanotubes (MWCNT). The modified electrode showed an excellent electrochemical activity towards the oxidations and reductions of CC and HQ. At the GC/MWCNT/MnPc electrode both CC and HQ can generate a pair of quasi-reversible and well-defined redox peaks. Under the optimized experimental and operational conditions, the cathodic peak current was linear over the 1.0 x 10-6 mol L-1 to 6.0 x 10-4 mol L-1 range for both CC and HQ, with detection limits of 0.95 and 0.41 ?mol L-1, respectively. In addition, anodic peak current were linear over the 1.0 x 10-6 mol L-1 range to 6.0 x 10-4 mol L-1 for both CC and HQ, with detection limits of 0.96 and 0.48 ?mol L-1, respectively. The proposed method was effectively applied to the simultaneous detection of hydroquinone and catechol in water samples.; O presente trabalho descreve o desenvolvimento de um sensor voltam?trico seletivo e sens?vel para a determina??o simult?nea de catecol (CC) e hidroquinona (HQ) usando um eletrodo de carbono v?treo (ECV) modificado com ftalocianina de mangan?s (MnPc) adsorvida sobre nanotubos de carbono de paredes m?ltiplas (NTCPM). O eletrodo modificado apresentou uma excelente atividade eletroqu?mica tanto para oxida??o quanto para a redu??o de CC e HQ. No ECV/NTCPM/MnPc tanto CC...

‣ Efeitos da restri??o cal?rica desde o nascimento sobre o cora??o de ratos adultos

Melo, Dirceu de Sousa
Fonte: UFVJM Publicador: UFVJM
Tipo: Dissertação de Mestrado
Português
ABSTRACT There has been growing evidence suggesting that a severe caloric restriction (SCR) (above 40%) leads to beneficial effects on heart rats. However, most of the reports are focused on the effects of SCR on hearts of rats which started this restriction at adulthood. In this work, we investigated the consequences of a 50% caloric restriction since birth on cardiac morphology and function in adult rats and evaluated the possible mechanisms involved in these adaptations. From birth up to the age of 90 days CR50 rats were fed restricted at 50% of the Ad Libitum group (AL). During the period of 90 days the animals had their food intake, body weight and blood pressure monitored. After this period, a maximal aerobic test was performed in order to indirectly evaluate the global cardiovascular function. Forty-eight hours after this test the animals were euthanized the blood collected for analysis of hematocrit, serum biochemistry and oxidative stress and soleus muscle collected for oxidative stress analysis. The tibia was removed for measurement of length and liver, spleen, adrenals, testes and visceral fat were removed for measurement of weight. The heart was removed and the index of velocity of myocardial contraction (+dT/dt) and relaxation (-dT/dt) was analyzed by isolated heart preparation. We also carried out analysis of cardiac oxidative stress and cardiomyocyte diameter...

‣ Efeitos da adi??o da vibra??o de todo o corpo ao exerc?cio em cadeia cin?tica fechada (agachamento) sobre par?metros inflamat?rios e neuroend?crinos e a sua associa??o com o desempenho e a capacidade funcional em idosos com osteoartrite de joelho

Sim?o, Adriano Prado
Fonte: UFVJM Publicador: UFVJM
Tipo: Tese de Doutorado
Português
ABSTRACT Introduction: Recently, whole body vibration (WBV) has been an alternative method of exercise that has been indicated to improve the physical performance of the elderly with osteoarthritis (OA) knee. However, the mechanisms related to the effects produced by this training mode have not been fully elucidated in the literature. Objectives: 1) To investigate the effects of the adittion of whole-body vibration to squat exercises on the plasma concentration of inflammatory markers and the functional performance of elderly individuals with knee OA remission phase (Study 1) and investigate the effects of WBV in addition to squat exercise training in elderly women with knee OA remission phase on the following parameters: 1) isometric strength of the quadriceps muscle; 2) BDNF plasma concentration; and 3) the testosterone/cortisol salivary concentration ratio (Study 2). 3). To analyze the concentrations of TNF-?, soluble receptors (sTNFR1 and sTNFR2) and BDNF in both plasma and synovial fluid of patients with inflammatory acute phase primary knee osteoarthritis during inflammatory acute phase, and to determine the possible correlations of plasma and synovial fluid TNF-?, soluble receptors (sTNFR1 and sTNFR2) and BDNF with the radiographic grading of knee OA and with self-reported pain...

‣ An?lise da composi??o qu?mica, atividade citot?xica e inibi??o de citocinas in vitro de prepara??es de partes a?reas da planta ageratum fastigiatum

Freitas, Beth?nia Alves de Avelar
Fonte: UFVJM Publicador: UFVJM
Tipo: Tese de Doutorado
Português
ABSTRACT Ageratum fastigiatum is a plant used in folk medicine as topical anti-inflammatory and analgesic agent. However, few studies have been conducted with this plant in order to detail the molecular mechanisms involved in its biological activities. Therefore, main purpose of the present study was to investigate the anti-inflammatory activity of the essential oil and leaf rinse dichloromethane of A. fastigiatum extract. The cytotoxicity of the compounds was assessed by means of trypan blue exclusion. The essential oil at 5x10-3 e 1x10-2 ?L/ did not present cytotoxic activity. These two concentrations were used for investigating the anti-inflammatory potential of the essential oil, by analyzing the pro-inflammatory (TNF-? and IFN-?) and anti-inflammatory (IL-10) cytokine profiles on human leukocyte cultures stimulated and non-stimulated with PMA (phorbol myristate acetate). The data obtained by flow cytometry demonstrated that both concentrations decreased the percentage of lymphocytes ?TNF-? + on the cell cultures stimulated with PMA. In the non-stimulated cell cultures there were no changes in the percentage of IL-10+ cells. The gas phase chromatography coupled with mass spectrometry analysis (GC/MS) revealed that the main compounds present in oil samples were: ?-pinene (7.51%)...

‣ Influ?ncia da vibra??o de todo o corpo sobre os par?metros mec?nicos, fisiol?gicos e desempenho f?sico em homens fisicamente ativos

Avelar, N?bia Carelli Pereira de
Fonte: UFVJM Publicador: UFVJM
Tipo: Tese de Doutorado
Português
ABSTRACT Introduction: Recently, whole body vibration (WBV) has been an alternative method of exercise that is increasingly used to improve the physical performance of athletes. However, the mechanisms related to the effects produced by this training mode have not been fully elucidated in the literature. Objectives: The objectives of this study were to define the protocol of WBV able to increase muscle performance in athletes (Studies 1 and 2) and propose possible physiological mechanisms of WBV on physical performance (studies 3, 4 and 5). Methods: In study 1 was evaluated the influence of different angles of knee flexion and adittion of WBV in the vastus lateralis muscle activation and transmissibility of vibratory stimulus to propose the best body position for this exercise. In this study, 34 individuals had electromyography activity (EMG) of the vastus lateralis and the acceleration assessed while squatting with 60? and 90? of knee flexion either with or without whole-body vibration (WBV: 30 Hz, 4mm). In study 2 was proposed to evaluate the dose-response curve of vibratory stimulation on muscle performance of the lower and upper limb. Nine recreationally males were subjected to five experimental conditions: 1) Squat exercise (SE) without WBV; 2) SE/WBV [20 Hz...

‣ Sele??o de isolados de pisolithus para mudas clonais de eucalipto em viveiro comercial

Fonseca, Arley Jos?
Fonte: UFVJM Publicador: UFVJM
Tipo: Dissertação de Mestrado
Português
A inocula??o de fungos ectomicorr?zicos em mudas clonais de eucalipto pode promover o crescimento delas, principalmente ap?s o plantio no campo, mas este efeito ? dependente do fungo, da planta hospedeira e das condi??es ambientais. O objetivo deste trabalho foi selecionar isolados de fungos ectomicorr?zicos para programas de inocula??o em viveiros comerciais de eucalipto clonal. Para isto foram montados dois experimentos, um em viveiro comercial, e outro em vasos mantidos em casa de vegeta??o onde simulou-se a condi??o de campo, em que mudas j? formadas inoculadas e n?o-inoculadas foram plantadas em solo. O experimento em viveiro objetivou selecionar isolados de Pisolithus sp. que colonizem mudas clonais de eucalipto em condi??es de viveiro comercial. O delineamento utilizado foi inteiramente casualizado, em esquema fatorial 2 x 17, sendo: os clones de eucalipto GG100, h?brido de Eucalyptus urophylla, e o GG680, h?brido do cruzamento de E. urophylla com Eucalyptus grandis, inoculados com 15 isolados de Pisolithus sp. e crescidos em substrato com redu??o da aduba??o fosfatada; e os controles n?o inoculados com (Controle) e sem (Comercial) redu??o da aduba??o fosfatada do substrato, com cinco repeti??es. As conclus?es obtidas foram que a inocula??o de isolados de Pisolithus promove a coloniza??o ectomicorr?zica...

‣ Influ?ncia do glyphosate na anatomia e fisiologia de cultivares de caf? ar?bica

Reis, Lilian Alves Carvalho
Fonte: UFVJM Publicador: UFVJM
Tipo: Dissertação de Mestrado
Português
O manejo das plantas daninhas possui grande import?ncia para a manuten??o dos n?veis produtivos da cultura do caf?. O herbicida mais utilizado mundialmente na cultura do caf? ? o glyphosate, por possuir alta efici?ncia e ser mais barato. Ele atua inibindo a enzima 5-enolpiruvilshiquimato, respons?vel pela produ??o de tr?s amino?cidos tirosina, fenilalanina, tryptofano. Influenciando assim a produ??o de metabolitos secund?rios, inclusive os relacionados a forma??o das estruturas anat?micas, metabolitos de defesa e fotoss?ntese. Objetivou-se no presente trabalho avaliar os efeitos da deriva simulada de glyphosate sobre a anatomia e fisiologia de cultivares de caf? arabica. Para isso, fez-se tr?s avalia??es diferenciadas visando avaliar modifica??es primeiramente morfoanat?micas, depois concentra??es de fen?is totais, flavon?ides, cafe?na e por ultimo, floresc?ncia, concentra??es de clorofilas e quantifica??es de est?matos. O experimento foi instalado em esquema fatorial (3 x 5), com tr?s cultivares de caf? MGS Travessia, Oeiras MG 6851 e Catua? IAC 144, e cinco doses de glyphosate (0,0; 57,6; 115,2; 230,4 e 460,8 g ha-1), em delineamento de blocos casualizados, com quatro repeti??es. Trinta dias ap?s a aplica??o, foram coletadas doze folhas rec?m-expandidas do ?ltimo ramo plagiotr?pico do cafeeiro...

‣ Efeito cr?nico do tabagismo no perfil inflamat?rio, estresse oxidativo e desempenho f?sico em homens assintom?ticos

Neves, Camila Danielle Cunha
Fonte: UFVJM Publicador: UFVJM
Tipo: Dissertação de Mestrado
Português
O efeito do consumo cr?nico do cigarro no perfil inflamat?rio, estresse oxidativo e desempenho f?sico t?m sido investigado em fumantes assintom?ticos, contudo, estes estudos na sua maioria ainda s?o poucos e divergentes. Sendo assim, o objetivo deste estudo foi avaliar o efeito cr?nico do tabagismo no perfil inflamat?rio, estresse oxidativo, fun??o muscular esquel?tica perif?rica e aptid?o cardiorrespirat?ria de homens adultos assintom?ticos. Os sujeitos do estudo foram divididos igualmente entre o grupo fumante (GF, n= 20) e grupo controle (GC, n= 20), composto por sujeitos n?o fumantes. A fun??o pulmonar de todos participantes foi avaliada pela espirometria. O perfil inflamat?rio foi avaliado pela mensura??o das concentra??es plasm?ticas das citocinas IL-6, TNF-?, IL-10 e pelos receptores sol?veis de TNF-? (sTNFR1 e sTNFR2). O estresse oxidativo foi avaliado pela mensura??o das concentra??es plasm?ticas das subst?ncias reativas ao ?cido tiobarbit?rico (TBARS), da atividade das enzimas antioxidantes super?xido dismutase (SOD) e catalase de eritr?citos e pela capacidade antioxidante total do plasma. A fun??o muscular esquel?tica perif?rica foi avaliada por meio das medidas de pico de torque dos m?sculos extensores e flexores de joelho e da resist?ncia e fadiga muscular dos m?sculos extensores de joelho; e a aptid?o cardiorrespirat?ria foi avaliada atrav?s da mensura??o do consumo pico de oxig?nio (VO2pico)...

‣ Desenvolvimento de dispositivo de fototerapia para aumento de desempenho e recupera??o do exerc?cio f?sico de alta intensidade e curta dura??o

Telles, Maria Cec?lia
Fonte: UFVJM Publicador: UFVJM
Tipo: Dissertação de Mestrado
Português
Introdu??o: A capacidade de um indiv?duo gerar e manter pot?ncia pico elevada ? fundamental para o desempenho no exerc?cio f?sico de alta intensidade. Assim, o desenvolvimento e o estudo de novas tecnologias que possam aprimorar a desempenho ou minimizar a ocorr?ncia de les?es durante a recupera??o de exerc?cio de alta intensidade poderiam contribuir para a melhora da prepara??o e planejamento do treinamento. Objetivos: Confeccionar um aparelho para terapia com diodo emissor de luz, em um ?nico comprimento de onda, com uma maior ?rea de irradia??o e avaliar a influ?ncia desta terapia no desempenho f?sico, bem como em componentes metab?licos, par?metros inflamat?rios e de les?o muscular durante o per?odo de recupera??o de exerc?cio de alta intensidade e curta dura??o (30-s) no cicloerg?metro em homens fisicamente ativos e ciclistas. Metodologia: Primeira fase: (Estudo 1) Realizou-se estudo randomizado e balanceado para avaliar o desempenho, onde foram irradiadas 4 doses de terapia LED: LED placebo (0 J/cm2), LED 21s (3,6J/cm2), LED 42s (7,2J/cm2), LED 84s (14,4J/cm2), em dias distintos, com 24h de intervalo, antes de cada teste de Wingate (TW). (Estudo 2) 4 homens foram submetidos a coletas de sangue antes e ap?s (3, 60, 120 minutos e 24 horas) a realiza??o de TW para mensura??o das concentra??es plasm?ticas de CK...

‣ Rela??o entre hipertens?o arterial sist?mica e efici?ncia da troca de calor durante a recupera??o ao exerc?cio f?sico realizado em ambiente quente

Fonseca, Sueli Ferreira da
Fonte: UFVJM Publicador: UFVJM
Tipo: Dissertação de Mestrado
Português
ABSTRACT Purpose: The systemic arterial hypertension is associated with sympathetic hypertonia dependent on central cholinergic activity. Thus, it is believed that hypertensive individuals have an enhanced response of heat dissipation, especially during recovery from moderate-intensity exercise performed under heat stress conditions. Thus, the aim of this study was to examine the thermoregulatory responses of hypertensive subjects during and after (recovery period) moderate-intensity exercise performed in the heat. Methods: A total of 8 essential hypertensive (H) and 8 normotensive participants (N) (age: 46.5 ? 1.3 and 45.6 ? 1.4 years, BMI: 25.8 ? 0.8 and 25.6 ? 0.6 kg/m2, mean arterial pressure: 98.0 ? 2.8 and 86.0 ? 2.3 mmHg, respectively) remained in the environmental chamber (38 ?C and 60 % relative humidity) for 2 hours and 30 minutes (30 min at rest, 1 h of treadmill exercise at 50 % of VO2max and 1 h at rest during recovery exercise). Skin and core temperatures, heart rate and blood pressure were measured. Calculations of heat production, heat storage, mean body temperature, heat exchange by radiation, convection and evaporated sweat were performed from the collected variables. Results: The mean blood pressure of the hypertensive subjects was higher than of the normotensive participants throughout the experimental protocol (p < 0.05). Although the thermoregulatory parameters evaluated did not differ between groups at rest and during exercise...

‣ Produ??o de biodiesel a partir de ?leos e gorduras residuais utilizando ?cido sulf?rico imobilizado em s?lica como catalisador e aplica??o do glicerol na produ??o de cetal; Biodiesel production from waste cooking oil using sulfuric acid as catalyst immobilized on silica and applied of glycerol in the production of ketal

Macedo, Alice Lopes
Fonte: UFVJM Publicador: UFVJM
Tipo: Dissertação de Mestrado
Português
ABSTRACT The heterogeneous catalysts developed by our research group based Lewis acid supported on various inorganic oxides such as: ZnCl2/SiO2 and FeSO4/SiO2, has proved excellent for esterification of free fatty acids, but ineffective when applied in the transesterification vegetable oils. This paper proposes the synthesis and study of a catalyst produced from the Br?nsted-Lowry acids sulfuric acid in replacement of previously employed Lewis acids. Waste oils and fats generally contain a high content of free fatty acids (FFA), as well as a high water content, these substances hinders the action of basic catalysts such as NaOH or KOH which are widely used in these processes, taking also inhibition of some catalysts from the mineral acids. The new catalyst mixture (H2SO4/SiO2) was synthesized from 10 M sulfuric acid immobilized on silica 24 mesh, previously prepared from construction sand and sodium carbonate. Later this material was characterized using the following analytical techniques, Scanning Electron Microscopy, Spectroscopy Dispersion Energy, Infrared and thermogravimetric analysis. Initially, the catalyst was applied in transesterification of vegetable oils and refined oils and waste fats purified. However, the most challenge was to perform the transesterification of vegetable oils of low quality...

‣ Pept?deo antimicrobiano homotarsinina: s?ntese, estudos reacionais de dimeriza??o e ensaios de citotoxicidade

Guimar?es, Carlos Felipe Reis Costa
Fonte: UFVJM Publicador: UFVJM
Tipo: Dissertação de Mestrado
Português
ABSTRACT This dissertation is mainly related to studies concerning the role of the structural effects on the dimerization reaction that leads to the antimicrobial peptide homotarsinin (Htr). Besides, hemolytic assays as well as the toxicity of this peptide against human cells have also been investigated. Firstly, the monomeric chain (Htr-M) was obtained by Fmoc solid-phase synthesis. The product was purified by reverse phase high performance liquid chromatography (RP-HPLC) and then sequenced and characterized by mass spectrometry (MALDI-ToF). Circular dichroism (CD) studies regarding the Htr-M conformational preferences were performed for the peptide in different media and conditions, such as Tris-HCl aqueous buffer, TFE:H2O mixtures, as well as in the presence of SDS micelles. The dimerization reaction was then performed in three distinct media, namely: (i) Tris-HCl aqueous buffer 100 mmol?L-1 pH 8.5, (ii) SDS micellar solution of 350 mmol?L-1 in Tris-HCl 100 mmol?L-1 pH 8.5 and (iii) TFE:H2O 40:60 in Tris-HCl 100 mmol?L-1 pH 8.5. CD studies performed in similar conditions indicated that Htr-M presents predominantly random conformations in aqueous Tris-HCl buffer, whereas it adopts ?-helical arrangements in either TFE:H2O (40:60) solution or in the presence of SDS micelles. The kinetic monitoring of the dimerization reactions was carried out by RP-HPLC. The results indicated that the reaction is completed in about 6 h (yield 62%) in the presence of SDS micelles...

‣ Determina??o simult?nea de ?cido ?rico e epinefrina empregando um sensor ? base de nanotubos de carbono e bis-tetracianoquinodimetaneto de tris- fenantrolina de cobre (ii); Development and application of a voltammetric sensor for simultaneous analysis of Uric Acid and Epinephrine in the presence of Ascorbic Acid employing a glassy carbon electrode modified with (tris(1,10-phenantroline)copper(II) bis(tetracyanoquinodimethanide)) functionalized multi-wall carbon nanotubes

Pimentel, Dilton Martins
Fonte: UFVJM Publicador: UFVJM
Tipo: Dissertação de Mestrado
Português
?rea de concentra??o: Qu?mica Anal?tica; ABSTRACT A sensitive and selective sensor for determination of uric acid and epinephrine in the presence of ascorbic acid by differential pulse voltammetry using a glassy carbon electrode modified with Cu(phen)3(TCNQ)2 (tris(1,10-phenantroline)copper(II) bis(tetracyanoquinodimethanide)) functionalized multi-wall carbon nanotubes was developed in this work. The composite was characterized by Scanning Electron Microscopy, Electrochemical Impedance Spectroscopy and Fourier Transform Infrared Spectroscopy. The anodic and cathodic transfer coefficients and the standard rate transfer constant for electrochemical reaction of functionalized nanotubes were determined; the found values were 0,58, 0,41 and 2,9 s-1, respectively. The number of electrons and the heterogeneous rate constant involved in the oxidation reaction of uric acid and epinephrine was calculated, the values obtained were 2 electrons, 2.6 x 104 for 0.1 mmolL-1 and 1.2 x 104 mol-1s-1L for 0.5 mmolL-1 of uric acid and 2 electrons, 3.5x105 for 0,1 mmolL-1 and 1.1x104 mol-1s-1L for 0.5 mmolL-1 of epinephrine. A linear response range from 20 up to 440 ?molL-1, with a sensitivity of 0.024 A.L.mol-1, quantification and detection limits of 23.23 and 7 ?molL-1 for epinephrine and linear response range from 10 up to 420 ?molL-1...

‣ Desenvolvimento e aplica??o de um biossensor ? base da enzima acetilcolinesterase empregando NTCPM/CoTSPc para a determina??o de pesticidas organofosforados

Pereira, Neuma das Merc?s
Fonte: UFVJM Publicador: UFVJM
Tipo: Dissertação de Mestrado
Português
ABSTRACT In this work, a highly sensitive acetylcholinesterase (AChE) inhibition-based amperometric biosensor has been developed. The method is based on a cobalt phthalocyanine tetrasulfonate and 1-methyl-3-octylimidazolium tetrafluoroborate ionic liquidmodified nanotubes paste electrode. Images Scanning Electron Microscopy and Spectroscopy Fourier Transform Infrared were used to characterize the materials. The thiocholine oxidation process was investigated by cyclic voltammetry (CV) and chronoamperometry. The AChE enzyme was immobilized on the composite electrode surface by cross-linking with glutaraldehyde and chitosan. The synergistic action of NTCPM/CoTSPc/AChE showed excellent electrocatalytic activity with low applied potential for the detection of thiocholine. Parameters affecting the biosensor response such as enzyme loading, incubation time, pH and concentration of the buffer solution were optimized utilizing acetylthiocholine chloride (ATChCl) as substrate. The results showed that the fenitrothion, dichlorvos and malathion can lead to a reversible inhibition process of the enzyme. This biosensor showed low detection limit, good reproducibility, high stability and was used to determine pesticides in water samples. Linear relationships were found for fenitrothion (1.0-1000.0 pmol L-1)...