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1.
Rev. colomb. quím. (Bogotá) ; 51(1): 40-47, Jan.-Apr. 2022. tab, graf
Article in Spanish | LILACS-Express | LILACS | ID: biblio-1408080

ABSTRACT

Resumen La actividad cafetalera en Costa Rica procesa aproximadamente 69.000 toneladas de café mediante la técnica de beneficiado húmedo. Esta actividad conlleva un alto impacto ambiental debido a la generación de8Lde agua residual/kg de café oro producido. El presente trabajo tiene como objetivo utilizar el agua residual del procesamiento de café como sustrato en celdas combustibles microbianas (CCM), con el propósito de generar energía eléctrica a través de su uso y, a la vez, disminuir la carga orgánica del residuo. La CCM empleó un cátodo modificado con ftalocianinas de hierro (FePc), generó una eficiencia coulómbica de 0,7% y una densidad de potencia de 89 UW/ cm2 en un ciclo de operación de cinco días. Además, se determinó que la CCM disminuye la demanda química de oxígeno (DQO) del residuo hasta en 27% bajo las condiciones de operación nativas del sustrato, a temperatura ambiente, sin mediadores químicos para la reacción anódica y con el uso de electrodos de platino para el cátodo. El estudio confirma la oportunidad de emplear el sustrato con una flora microbiana nativa apta para la operación de la tecnología de la CCM, y así perfilar el dispositivo como una opción novedosa para el tratamiento de este residuo en Costa Rica.


Abstract In Costa Rica coffee production is the most traditional agroindustrial activity, each year approximately 69,000 tons of coffee are processed through the technique of wet processing. The process has a high environmental impact since it generates eight liters of wastewater/kg of produced coffee. Consequently, the main goal of this research was to evaluate the electric generation of a Microbial Fuel Cell (MFC) with two chambers, using coffee wastewater as a substrate, which would generate a sustainable solution with an added economic value to this waste in Costa Rica. The MFC with a cathode modified with iron phthalocyanines (FePc) generated a coulombic efficiency of 0.7% and a power density of 89 -uW/cm2 in a 5-day operation cycle. In addition, it was determined that the MFC decreases the COD of the waste by up to 27% under native substrate conditions, without the use of high temperatures, or chemical mediators for the anodic reaction and platinum electrodes for the cathode chamber. The efficiency of the device can be improved with changes at design level that reduce the ohmic internal resistance and improve electrical generation, the study confirms the potential of the substrate with a native microorganism suitable for the use of MFC technology, shaping the device as a novelty option for the treatment of the waste in Costa Rica.


Resumo A indústria do café na Costa Rica processa cerca de 69 000 toneladas de café por meio da técnica de moagem úmida, o que acarreta um alto impacto ambiental devido à geração de 8 L de água residual / kg de café dourado. O objetivo deste trabalho era usar águas residuais do processamento do café como substrato em Células de Combustível Microbianas (CCM) a fim de gerar energia elétrica por meio do seu aproveitamento e ao mesmo tempo reduzir a carga orgânica do resíduo. CCM usando cátodo modificado com ftalocianinas de ferro (FePc) gerou uma eficiência coulômbica de 0,7% e uma densidade de potência de 89 uW/cm2 em um ciclo operacional de cinco dias. Além disso, foi determinado que o CCM reduz a Demanda Química de Oxigénio (DQO) do resíduo em até 27% nas condições nativas de operação do substrato, à temperatura ambiente, sem mediadores químicos para a reação anódica e com a utilização de eletrodos de platina para o cátodo. O estudo confirma a oportunidade de utilizar o substrato com flora microbiana nativa adequada para o funcionamento da tecnologia CCM e, assim, delinear o dispositivo como uma nova opção para o tratamento desses resíduos na Costa Rica.

2.
Rev. peru. biol. (Impr.) ; 27(1): 43-48, ene.-mar 2020.
Article in English | LILACS-Express | LILACS | ID: biblio-1144929

ABSTRACT

Abstract The various industrial sectors, as well as livestock and agricultural activities, are increasing the production of inputs to meet the demand of the worldwide demographic explosion, making a challenge the clean maintenance of water, soil, and air. Therefore, the search for solutions for a pollutant-free environment without compromising economic development has become extremely important. Thereby, biotechnological studies in order to solve environmental issues have been gaining extensive attention through the coupling of technology procedures to biological systems as sustainable solutions to remediate contaminated areas. In this sense, this review covers topics such as the role of Omics era in microbial environmental biotechnology for pollution control as well as the microbial fuel cell use in energy production. Moreover, phytoremediation and the perspective of applying chemical methods are approached as environmentally friendly tools for the pollutant control to improve remediation processes.


Resumen Los diversos sectores industriales, así como las actividades ganaderas y agrícolas, están aumentando la producción de insumos para satisfacer la demanda de la explosión demográfica mundial, lo cual dificulta el mantenimiento limpio del agua, el suelo y el aire. Por lo tanto, la búsqueda de soluciones para un medio ambiente libre de contaminantes sin comprometer el desarrollo económico se ha vuelto extremadamente importante. De este modo, los estudios biotecnológicos para resolver problemas ambientales han recibido una gran atención a través del acoplamiento de procedimientos tecnológicos a sistemas biológicos como soluciones sostenibles para remediar áreas contaminadas. En este sentido, esta revisión cubre temas como el papel de la era Ómica en la biotecnología ambiental microbiana para el control de la contaminación, así como el uso de celdas de combustible microbianas en la producción de energía. Además, la fitorremediación y la perspectiva de aplicar métodos químicos se abordan como herramientas ecológicas para el control de contaminantes y mejorar los procesos de remediación.

3.
Article in Chinese | WPRIM | ID: wpr-865658

ABSTRACT

5-Dimethylaminopropylamino-8-hydroxytriazoloacridinone (C-1305) is a promising antitumor com-pound developed in our laboratory. A better understanding of its metabolic transformations is still needed to explain the multidirectional mechanism of pharmacological action of triazoloacridinone de-rivatives at all. Thus, the aim of the current work was to predict oxidative pathways of C-1305 that would reflect its phase Ⅰ metabolism. The multi-tool analysis of C-1305 metabolism included electrochemical conversion and in silico sites of metabolism predictions in relation to liver microsomal model. In the framework of the first approach, an electrochemical cell was coupled on-line to an electrospray ioni-zation mass spectrometer. The effluent of the electrochemical cell was also injected onto a liquid chromatography column for the separation of different products formed prior to mass spectrometry analysis. In silico studies were performed using MetaSite software. Standard microsomal incubation was employed as a reference procedure. We found that C-1305 underwent electrochemical oxidation pri-marily on the dialkylaminoalkylamino moiety. An unknown N-dealkylated and hydroxylated C-1305 products have been identified. The electrochemical system was also able to simulate oxygenation re-actions. Similar pattern of C-1305 metabolism has been predicted using in silico approach. Both proposed strategies showed high agreement in relation to the generated metabolic products of C-1305. Thus, we conclude that they can be considered as simple alternatives to enzymatic assays, affording time and cost efficiency.

4.
Article in Chinese | WPRIM | ID: wpr-847705

ABSTRACT

BACKGROUND: Electrochemical method based nanoscale hydroxyapatite coating has slow degradation speed (8-12 weeks). Micro-arc oxidation based method could form homogeneous coating on complex surfaces, and this coating promotes cell adhesion and ingrowth in bone tissues. OBJECTIVE: To explore the effect of micro-arc oxidation hydroxyapatite coating titanium alloy on osteoblast proliferation and osteogenic differentiation ability. METHODS: Hydroxyapatite coating titanium alloy materials were prepared by electrochemical method and micro-arc oxidation method. The contact angles of the two materials were detected. Osteoblasts (hFOB1.19) were incubated on the hydroxyapatite coating titanium alloy materials for 48 hours. The morphological changes of osteoblasts on the materials were observed under scanning electron microscope. The cell proliferation was detected by MTT method at 1, 12, 24, 48 and 72 hours. The cell count and alkaline phosphatase activity were detected at 1, 3 and 5 days of culture. At 5 days, the expression levels of bone morphogenetic proteins 2 and 4 were detected by western blot assay. RESULTS AND CONCLUSION: (1) The contact angle in the micro-arc oxidation group was smaller than that in the electrochemical group [(66.5±2.2)°, (52.8±2.1)°, P=0.001 5)]. (2) Scanning electron microscope revealed that the osteoblasts in the electrochemical group had an irregular and shrunken shape, and adhered loosely to the material surface. The osteoblasts in the micro-arc oxidation had a fully outstretched and flat shape, and adhered tightly to the material surface. (3) From 12 to 72 hours, the cell proliferation in the micro-arc oxidation group was faster than that in the electrochemical group (P < 0.05). At 3 and 5 days after culture, the cell proliferation in the micro-arc oxidation group was faster than that in the electrochemical group (P < 0.05). (4) At 1, 3 and 5 days, the alkaline phosphatase activity of osteoblasts in the micro-arc oxidation group was higher than that in the electrochemical group (P < 0.05). (5) The expression levels of bone morphogenetic proteins 2 and 4 were significantly up-regulated in the micro-arc oxidation group compared with the electrochemical group (P < 0.05). (6) These results indicate that micro-arc oxidation hydroxyapatite coated titanium alloy increases osteoblast proliferation and osteogenic differentiation ability.

5.
Braz. dent. sci ; 22(1): 70-78, 2019. tab, ilus
Article in English | LILACS, BBO | ID: biblio-986838

ABSTRACT

This work studied the synthetization and morphological characterization of Polyethylmethacrylate (PEMA) nanofibers (NFs) containing titanium dioxide (TiO2) produced by the electrospinning technique. The solution to produce the nanofibers was prepared by dissolving 2.5g PEMA in 6.75mL of 1.1.2.2- tetrachloroethane and 3.375mL of dimethylformamide (DMF), and 0.405g of TiO2 was added to the solution. The nanofiber production used different distances between the tip of the needle to the collector (10, 12 and 15 cm) and two flow rates (0.05 mLh-1 and 0.08 mLh-1) were employed, while the applied voltage was 17kV. The NF morphology was analyzed by Scanning Electron Microscopy (SEM) and Image J software. We used Fourier Infrared Spectroscopy (FTIR) and Energy Dispersive X-Ray Spectroscopy (EDS) to evaluate the structural properties. All parameters were effective in the NF production, however it was shown that the distance of 12 cm produced the best NFs. The mean diameters showed no statistically significant difference between the samples. The FTIR analysis showed characteristic peaks of PEMA and TiO2 . It was concluded that the employed method was efficient for NF production containing PEMA and TiO2 , and the morphological characteristics of the NFs were influenced by the voltage and distance. (AU)


O presente trabalho estudou a sintetização e a caracterização morfologica de nanofibras (NFs) de polietilmetacrilato (PEMA) contendo dióxido de titânio (TiO2) produzidas pela técnica da eletrofiação. A solução para o preparo das nanofibras utilizou 2,5 g de PEMA dissolvidos em 6,75 mL de 1,1,2,2 - tetracloroetano (TCE) e 3,337 mL de dimetilformamida (DMF), em sequência foi adicionado 0, 405g de TiO2 à solução. Para eletrofiação, o equipamento foi constituído por uma fonte de alta tensão, uma seringa plástica com agulha de ponta reta e as NFs obtidas foram coletadas em anteparo metálico a 10, 12 e 15 cm de distância da ponta da agulha. A tensão aplicada foi de 17 kV e o fluxo de ejecção variou de 0.05 mLh-1 e 0.08 mLh1. O diâmetro e a morfologia das NFs foram avaliados por meio de Microscopia Eletrônica de Varredura (MEV) e pelo software Image J. A Espectroscopia por Transformada de Fourier (FTIR) e a Spectroscopia por energia dispersiva de raios X (EDS) avaliaram as propriedades estruturais. A análise morfológica das micrografias mostrou que a distância de 12cm da ponta da agulha até o coletor produziu as melhores NFs. O FTIR demonstrou picos característicos de PEMA e TiO2 . Diante dos resultados obtidos podemos concluir que o método empregado foi eficiente para a produção de NFs contendo PEMA e TiO2 e a variação da tensão e distancia influenciaram na morfologias das NFs.(AU)


Subject(s)
Polymers , Microscopy, Electron, Scanning , Electrochemistry , Nanofibers
6.
Chinese Journal of Stomatology ; (12): 257-262, 2019.
Article in Chinese | WPRIM | ID: wpr-810553

ABSTRACT

Objective@#To investigate the stress corrosion and electrochemical corrosion resistance of titanium produced through laser rapid forming (LRF), and to provide a basis for their clinical application.@*Methods@#Forged commercial pure titanium (CP-Ti) was used as control group and LRF pure titanium was used as LRF group. All samples were placed in acidic artificial saliva containing fluorine (pH=7), and loaded with a stress of 1.2 × σ0.2 Pa (σ0.2 represents the yield strength of material). Stress corrosion resistance of specimens that have been soaked for 30 days was analyzed by naked eye observation, X-ray diffraction analysis and scanning electron microscopy. For samples placed in artificial saliva, neutral fluoride solution (pH=7) and acidic fluoride solution (pH=3) (4 test pieces in each corrosive medium), and their electrochemical corrosion resistance was evaluated by free corrosion potential (Ecorr) measurements, corrosion current (Icorr), electrochemical impedance spectroscopy (EIS), and anodic polarization curves.@*Results@#With the prolongation of immersion time, the corrosion products gradually increased. The stress corrosion of CP-Ti group was significantly more than that of LRF-Ti group, and the pit diameter was significantly larger than that of LRF-Ti group. The electrochemical corrosion results showed that the Ecorr (-469 mV) of LRF-Ti in artificial saliva was higher than that of CP-Ti (-555 mV), and the Ecorr (-925 mV) of LRF-Ti was higher than that of CP-Ti (-943 mV) in neutral fluoride solution. In acid fluoride solution, the Ecorr (-943 mV) of LRF-Ti was higher than that of CP-Ti (-956 mV). The Ecorr of the same metal was the highest in artificial saliva and the lowest in acid fluoride solution; the Icorr of the same metal was the lowest in artificial saliva and the highest in acid fluoride solution.@*Conclusions@#Under the same corrosion conditions, LRF Ti demonstrated better stress and electrochemical corrosion resistance than CP-Ti.

7.
Article in Chinese | WPRIM | ID: wpr-862103

ABSTRACT

Electrocoagulation technology has excellent effect for the treatment of intracranial aneurysms. However, the pathophysiological mechanism, safety and long-term recurrence of intravascular electrocoagulation are still controversial. The mechanism of electrocoagulation thrombosis and the advancements of its application in treatment of intracranial aneurysms were reviewed in this article.

8.
Chinese Journal of Biotechnology ; (12): 195-203, 2019.
Article in Chinese | WPRIM | ID: wpr-771387

ABSTRACT

Environmental protection and energy supply are our two major concerns. Greenhouse gases released from energy consumption have serious impact on the environment. CO₂ fixation can be used to convert CO₂ into fuels or chemicals. However, natural carbon-fixing organisms usually have some disadvantages such as slow growth and low carbon fixation efficiency. Enhancing or remodeling CO₂ fixation pathways in model microorganisms can realize CO₂ recycling, which can further increase fuel or chemical production and reduce greenhouse gas emission. This review describes in detail metabolic engineering of CO₂ fixation pathways to improve chemical production and sugar synthesis, elaborates the role of relevant metabolic pathways and key enzymes in CO₂ fixation, introduces the application of electro-biochemical synthesis system, shows the great potential of CO₂ fixation, and prospects the future research direction of CO₂ fixation.


Subject(s)
Carbon Cycle , Carbon Dioxide , Heterotrophic Processes , Metabolic Engineering , Metabolic Networks and Pathways
9.
Rev. colomb. quím. (Bogotá) ; 47(2): 45-53, mayo-ago. 2018. tab, graf
Article in English | LILACS-Express | LILACS | ID: biblio-960199

ABSTRACT

Abstract The synthesis of new grid-type complexes of Co2+ and Fe2+ based on a highly soluble double hydrazone framework is reported. The data obtained from 1H NMR, FT-IR, and elemental analysis indicate that the complexes adopted a grid-like structure. Electronic properties of the metallogrids were analyzed by UV-Vis spectroscopy in chloroform, methanol, and dichloromethane. Additionally, cyclic voltammetry and square wave voltammetry were carried out in N,N-dimethylformamide (DMF). These compounds exhibited two oxidation processes corresponding to the organic ligand and several reductions events, comprising the ligand and metal centers. Furthermore, the interplay between the metal nature and the ligand framework was also studied in detail. These results represent an advancement in the chemistry of metallogrids not only because of the few reports concerning to the electrochemical properties found in the literature, but also for the design of novel hydrazone ligands of high solubility and easy preparation.


Resumen Se reporta la síntesis de nuevos complejos metálicos de Co2+ y Fe2+ tipo rejilla que contienen como ligando orgánico una doble hidrazona altamente soluble en solventes orgánicos. Los datos obtenidos de resonancia magnética nuclear (RMN 1H), espectroscopía infrarroja con transformada de Fourier (FT-IR) y análisis elemental indican que los complejos adoptaron una estructura de tipo rejilla. Las propiedades electrónicas de las metalo-rejillas fueron analizadas a través de espectroscopía UV-Vis en cloroformo, metanol y diclorometano. Adicionalmente, se realizaron medidas de voltamperometría cíclica y voltametría de onda cuadrada en DMF. Los complejos exhibieron dos procesos de oxidación atribuidos al ligando orgánico y a varios eventos reductivos que comprometían al ligando y a los centros metálicos, por tanto, la interacción entre la naturaleza del ion metálico y la estructura del ligando fue analizada en detalle. Estos resultados representan un avance en la química de metalo-rejillas no solo por los escasos reportes de propiedades electroquímicas encontrados en la literatura, sino también por el diseño de nuevos ligandos hidrazónicos de alta solubilidad y fácil preparación.


Resumo Neste trabalho relata-se a síntese de novos complexos de Co2+ e Fe2+ tipo grelha baseados na estrutura de uma hidrazona dupla altamente solúvel em solventes orgânicos. Os dados obtidos de ressonância magnética nuclear (1H RMN), espectroscopia de infravermelho com transformada de Fourier (FT-IR), e análise elementar indicam que os complexos adotaram a estrutura tipo grelha. As propriedades eletrônicas das grelhas metálicas foram analisadas por espectroscopia UV-Vis em clorofórmio, metanol e diclorometano. Adicionalmente, foram realizadas medidas de voltametria cíclica e voltametria de onda quadrada em DMF. Os compostos estudados exibiram dois processos de oxidação correspondentes ao ligando orgânico, e a vários eventos redutivos que envolvem o ligando orgânico e os centros metálicos. Além disso, a interação entre a natureza do metal e a estrutura do ligando foi estudada em detalhe. Estes resultados representam um avanço na química de metalo-grelhas não somente pelos escassos relatos de propriedades eletroquímicas encontrados na literatura, mas também pelo design de novos ligandos hidrazônicos de alta solubilidade e fácil preparação.

10.
Rev. colomb. quím. (Bogotá) ; 47(2): 63-72, mayo-ago. 2018. tab, graf
Article in English | LILACS-Express | LILACS | ID: biblio-960201

ABSTRACT

Abstract A novel molecular system based on 2-((2-(4-chlorophenylhydrazone)methyl)quinoline (1-E ) was synthesized. Interconversion of 1-E to its configurational isomer 1-Z was achieved using UV radiation (250 W Hg lamp). Such isomerization was monitored by ¹H-NMR. The results suggest that the hydrazone derivative can act as a chemical brake in solution. This molecular system was structurally (Single Crystal X-Ray diffraction and DFT calculations) and spectroscopically (NMR, UV, and IR) characterized. Electrochemical measurements showed that configurational changes induce differential redox behavior. In this regard, the reported quinoline system exhibits different dynamic absorption and electrochemical properties that are modulated by UV-light. Therefore, 1-E can be regarded as a potential photo-electrochemical switch.


Resumen Se sintetizó un nuevo sistema molecular basado en 2-((2-(4-chlorofenilhidrazona)metil)quinolina. Del mismo modo, se evaluó la respuesta dinámica de este compuesto a radiación ultravioleta y formación de un enlace de hidrógeno intramolecular. Los resultados muestran que este derivado de hidrazona puede actuar como freno en solución. El sistema en mención es descrito estructural (Cristalografía de Rayos X y cálculos DFT) y espectroscópicamente (RMN, UV e IR). La interconversión de este sistema entre las configuraciones 1-E y 1-Z fue mediada por radiación UV y monitoreada a través de RMN-¹H. El estudio electroquímico mostró un comportamiento diferencial en función de su configuración, aspecto fundamental en el desarrollo de sistemas foto- y electroquímicamente modulados.


Resumo Neste trabalho é apresentado um novo sistema molecular baseado na 2-((2-(4-clorofenilhidrazona)metil)quinolina, capaz de responder dinamicamente à radiação ultravioleta formando uma ligação de hidrogénio intramolecular que atua como um freio na solução. Este sistema é descrito estruturalmente (cristalografia de raios-X e DFT) e por diferentes técnicas espectroscópicas (RMN, de UV e de IV). Radiação UV foi usada para fazer a interconversão da hidrazona 1-E no seu isômero configuracional 1-Z . Este processo foi monitorado pelo RMN. As medidas eletroquímicas mostraram que as mudanças configuracionais entre os isômeros induzem a comportamentos redox diferentes, o que é uma caraterística chave no desenvolvimento de interruptores fotoelectroquímicos.

11.
Article in Chinese | WPRIM | ID: wpr-692324

ABSTRACT

Isothermal nucleic acid amplifications, as powerful as polymerase chain reaction but functioning at a constant temperature, are considered to be very promising technique in achieving point-of-care gene diagnostics. However, until now, their practical applications are still seriously lagged by the bad reliability resulting from the problems such as false positive amplification and low signal amplitude. In this work, a universal transduction method in which any sequence ( including loop-mediated isothermal amplification products) could be transduced via a hairpin transducer into a catalyst of a well-engineered circuit (catalytic hairpin assembly, CHA) was established. Because CHA circuit could amplify tens to hundreds fold with especially high sequence specificity, it could provide both accuracy and high amplitude for sequence detection. And for a new targeting sequence, the only sequence needed to be changed was the hairpin transducer. Due to the importance of the transducer, we provided and verified a universal designing rule-set to guarantee the transducing efficiency ( signal to background ratio) of the transducer. Transducers designed following this rule set were then proved to be very efficient in detecting pathogen gene targets. As less as near single molecule ( 20 copies ) of pathogen genes could be detected with significant fluorescent and electrochemical signals.

12.
Article in Chinese | WPRIM | ID: wpr-692267

ABSTRACT

Palladium hydrogel capped by β-cyclodextrins (Pdβ-CD) was prepared by a facile method with β-cyclodextrins and palladium(II) chloride,which were then modified onto the surface of gold electrode. The morphology and structure of the as-prepared palladium hydrogel were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), while the electrochemistry behaviors of gold electrode modified by Pdβ-CDwere investigated by cyclic voltammetry (CV) and differential pulse voltammetry(DPV). The results indicated the sensor had high electrochemistry response to hydrazine hydrate in the presence of K+,Na+,Mg2+,NH+4,Ni+2,Mn2+,Cl-,NO-3,SO2-4,PO3-4,HCOO-, C6H5O-3. Under the optimized conditions, the oxidized peak current showed linear relationship with the concentration of hydrazine hydrate in the concentration range of 25-950 μmol/L and the limit of detection (LOD) of 1.6 μmol/L(S/N=3).Owing to the facile preparation,high sensitivity and selectivity,the sensor has potential applications in determination of hydrazine hydrate in real water samples

13.
Rev. Inst. Nac. Hig ; 48(1-2): 51-66, 2017. graf
Article in Spanish | LILACS, LIVECS | ID: biblio-999958

ABSTRACT

Se realizó el estudio voltamétrico de la inmovilización de anticuerpos anti-Escherichia coli ATCC 25922 en electrodos de oro desnudos y electrodos de oro modificados con tiourea. Las cepas de Escherichia coli fueron cultivadas durante 24 horas en medio tripticasa de soya, provenientes del Laboratorio de Microbiología del Agua de la Facultad de Farmacia y Bioanálisis de la Universidad de Los Andes en Mérida-Venezuela. Los resultados obtenidos muestran que ocurre la inmovilización de los anticuerpos anti-E. coli tanto en la superficie de los electrodos de oro desnudos, así como en los modificados con tiourea, ya que en ambos casos ocurre la detección de Escherichia coli. Al comparar ambos resultados, podemos decir que en oro desnudo el potencial de pico anódico es menor que en oro modificado con tiourea, +0,158V y +0,251V respectivamente; igual comportamiento ocurre con las corrientes de pico anódicas, 0,127x10-4A y 0,156x10-4A respectivamente. Un mayor potencial implica que la presencia de la monocapa de tiourea en el electrodo, hace que se dificulte la transferencia de electrones desde el anticuerpo al electrodo. Así mismo, los resultados obtenidos permiten sugerir un método para la inmovilización de moléculas biológicas en superficies de oro modificadas. De igual forma, el método utilizado permitió demostrar la especificidad de la unión anticuerpo-antígeno (anticuerpo-E.coli), al agregar volúmenes de Klebsiella pneumoneae, demostrando que el inmunosensor tiene la capacidad de reconocer la presencia o ausencia de E. coli en un medio, así como conocer si un anticuerpo es específico o no para un determinado antígeno


The voltammetric study of immobilization of anti-Escherichia coli antibodies ATCC 25922 was carried out on naked gold electrodes and gold electrodes modified with thiourea. The strains of Escherichia coli were cultivated for 24 hours in trypticase soybean medium, from the Laboratory of Microbiology of Water of the Faculty of Pharmacy and Bioanalysis of the University of Los Andes in Merida-Venezuela. The results obtained show that the immobilization of the anti-E. coli antibodies occurs on both the surface of the naked gold electrodes as well as those modified with thiourea, since in both cases the detection of Escherichia coli occurs. When comparing both results, we can say that in naked gold the anodic peak potential is lower than in gold modified with thiourea, +0.158V and +0.251V respectively; similar behavior occurs with the anodic peak currents, 0.127x10-4A and 0.156x10-4A respectively. Higher potential implies that the presence of the thiourea monolayer in the electrode makes it difficult to transfer electrons from the antibody to the electrode. Likewise, the results obtained suggest a method for the immobilization of biological molecules on modified gold surfaces. Likewise, the method used demonstrated the specificity of antibody-antigen (antibody-E.coli) binding, by adding volumes of Klebsiella pneumoneae, demonstrating that the immunosensor has the ability to recognize the presence or absence of E. coli in a medium, as well as to know if an antibody is specific or not for a certain antigen


Subject(s)
Humans , Male , Female , Biosensing Techniques , Electrochemistry , Escherichia coli , Antibodies, Immobilized , Bacteria , Water Microbiology , Public Health , Foodborne Diseases , Antibody Formation , Antigens
14.
Article in Chinese | WPRIM | ID: wpr-611862

ABSTRACT

The active copper-containing carbon nanodots were prepared by hydrothermal method, and then characterized by fluorescence spectroscopy and UV-visible absorption spectroscopy.Subsequently, a highly sensitive and selective electrochemical biosensor was fabricated on the basis of this synthesized carbon nanodots with electro-deposition technique.The electrode behavior was investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse voltammetry.Furthermore, the catalysis mechanism was studied.The experimental results indicated that the biosensor exhibited a strong electrocatalytic activity toward the oxidation of uric acid (UA).What′s more, the interference from ascorbic acid and dopamine was eliminated effectively.Under the optimum conditions, there were linear relationships between the anodic peak current and the concentration of UA (1.00-300.0 μmol/L), and the limit detection was 0.30 μmol/L (S/N=3).The prepared biosensor had advantages such as easy fabrication, strong anti-interference ability, high sensitivity, and wide detection range, and could be used for real sample detection.

15.
Article in Chinese | WPRIM | ID: wpr-503578

ABSTRACT

A new micro embedded telemetry system was developed for the amperometric sensing detection. Its output voltage range was ±0. 5 V and resolution was<1 mV. The current acquisition range was ±1μA and the minimum resolution was 0. 2 nA. This telemetry system was designed based on microprocessor ADuCM360, including a potentiostat, a current detection module and a radio module. And the size was only 24 mm × 13 mm × 11 mm. The computer software written in LabVIEW language was used for data storage and display. In order to verify the accuracy and reliability of this system, an electrical performance test was performed. The current response for ascorbic acid with different concentration was recorded by using the telemetry system. The potential of working electrode was set as 30 mV, and the current response of ascorbic acid electrode had a good linear relationship with its concentration within the concentration range of 50-300 μmol/L. Linear equation was I(nA) = 2. 98CAA(μmol/L)-137. 39, and linear correlation coefficient R2=0. 984. Moreover, the applicability of the instrument in the study for living animals was explored by using the cerebral ischemia as model.

16.
Article in Chinese | WPRIM | ID: wpr-457798

ABSTRACT

A wireless electrochemical recording device was designed for in_vivo neurotransmitters real_time detection. Low_power microcontroller MSP430 was chosen as main control unit in hardware system. Other modules were current detection module, waveform generator module and data transceiver module. This device had the merits of small size (2. 3 cm×1. 8 cm×0. 6 cm) and low power consumption. Firmware program design was based on uC/OS operating system. Combined with the PC software, the device could achieve online display and analysis of the recording data. For neurotransmitter detecting needs, the device implemented fast_scan cyclic voltammetry ( FSCV) and fixed_potential amperometry. By using fast_scan cyclic voltammetry method, a linear relationship ( R=0. 99 ) between the concentration of dopamine and response current was acquired in the range of 5. 0×10-7-7. 0×10-5 mol/L. In the in_vivo experiments, the electrically evoked dopamine was recorded in the caudate_putamen area of brain in rats. Experimental results showed that the system had high detection accuracy, which could realize qualitative and quantitative analysis of the brain neurotransmitter. This work would have a broad application prospect in the field of neuroscience research.

17.
Military Medical Sciences ; (12): 480-483, 2015.
Article in Chinese | WPRIM | ID: wpr-465756

ABSTRACT

Rapid detection of pathogenic microorganisms is important to the prevention and control of diseases.Com-pared with traditional approaches, electrochemical DNA biosensors present great advantages in promising rapid, portable, sensitive and cost-saving detection of pathogens.In this review, the working principle of electrochemical DNA biosensors and the progress in detection of pathogens is introduced, the latest developments of DNA tetrahedron structure and new nano materials in electrochemical DNA biosensors are reviewed, and the challenges to and prospects of development in this field are also discussed.

18.
Rev. colomb. quím. (Bogotá) ; 43(1): 1-1, ene.-jun. 2014. ilus, tab
Article in English | LILACS-Express | LILACS | ID: lil-747660

ABSTRACT

Herein we report the synthesis of the 6-(hydroxymethyl)pyridine-2-carboxaldehyde[2-methyl-pyrimidine-4,6-diyl]bis-hydrazone by a condensation reaction between 6-(hydroxymethyl)picolinaldehyde with 4,6-(bis-hydrazino)-2-methylpyrimidine. This bis-hydrazone can be visualized as a two-arm system which exhibits photochemical induced [E,E]/[E,Z]/[Z,Z’] isomerizations and double coordination to metal centers. Configurational changes, upon UV light irradiation, were followed over time by ¹H NMR, establishing that isomerization, in both arms, is a consecutive reaction that follows first-order kinetics (k1= 4.06 x 10-4 s-1 and k2= 2.80 x 10-4 s-1). Furthermore, the synthesis of bis-hydrazone metal complexes with La and Sm (III) ions was achieved; subsequently, the absorption and emission properties of these complexes were studied, determining the fluorescence quantum yields, ΦLa= 0.2024 and ΦSm= 0.1413. Electrochemical studies of the complexes were conducted by square wave voltammetry, demonstrating that the bis-hydrazone and its complexes are electroactive species between +1.5 and -2.5 V.


Se reporta la síntesis de la 6-(hidroximetil)piridin-2-carboxaldehído[2-metilpirimidina-4,6-diil]bishidrazona mediante la reacción de condensación entre el 6-(hidroximetil)piconaldehído con la 4,6-(bishidracino)-2-metilpirimidina. Esta bishidrazona puede ser visualizada como un sistema de dos brazos los cuales exhiben isomerizaciones [E,E]/[E,Z]/[Z,Z’] fotoquímicamente inducidas y coordinación a centros metálicos. Los cambios configuracionales, después de irradiación UV, fueron seguidos en el tiempo mediante RMN ¹H estableciendo que la isomerización, en ambos brazos del sistema, corresponde a una reacción consecutiva que sigue una cinética de primer orden (k1= 4,06 x 10-4 s-1 and k2= 2,80 x 10-4 s-1). Además se prepararon complejos metálicos de La y Sm(III), seguidamente, las propiedades de absorción y emisión de dichos complejos fueron estudiadas calculando rendimientos cuánticos de fluorescencia de ΦLa= 0,2024 y ΦSm= 0,1413. Estudios electroquímicos de los complejos se llevaron a cabo a través de voltametría de onda cuadrada indicando que los compuestos preparados poseen potenciales redox dentro del rango de trabajo del solvente.


Reporta-se a síntese da 6-(hidroximetil)piridin-2-carboxaldeído[2-metilpirimidina-4,6-diil]bis-hidrazona mediante a reação de condensação entre o 6-(hidroximetil)piconaldeído e a 4,6-(bis-hidrazino)-2-metilpirimidina. Esta bis-hidrazona pode ser visualizada como um sistema de dois braços os quais exibem isomerizações [E,E]/[E,Z]/[Z,Z’] fotoquimicamente induzidas e coordenação com íons metálicos (dupla coordenação a íons metálicos). Após a irradiação UV, as mudanças configuracionais foram monitoradas com o tempo por RMN 1H. Essas medidas estabeleceram que a isomerização em ambos braços do sistema corresponde a uma reação consecutiva apresentando uma cinética de primeira ordem (k1= 4.06 x 10-4 s-1 e k2= 2.80 x 10-4 s-1). Além disso, os complexos metálicos de La e Sm(III) foram preparados e suas propriedades de absorção e de emissão foram estudadas, calculando os rendimentos quânticos de fluorescência de ΦLa= 0.2024 e de ΦSm= 0.1413. Estudos eletroquímicos dos complexos foram feitos através de voltametria de onda quadrada indicando que os compostos preparados possuem potenciais redox dentro da faixa de trabalho do solvente.

19.
Article in Chinese | WPRIM | ID: wpr-671865

ABSTRACT

Objective To evaluate the detectability of HIV antigen-antibody in the window period of acute infection by three HIV antigen-antibody assays.Methods Twenty-two samples of HIV seroconversion serum panels and thirty-seven HIV acute infected plasm samples from our laboratory collected from cohort study of men who have sex with men between 2009 and 2011,were assayed by ECLIA,CLIA and ELISA methods.All assays were evaluated for the ability to detect HIV in the window period,and the sensitivity of each assay for acute samples was analyzed.Chi square test was used for statistical analysis.Results The ability of detecting HIV in the window period of each assay was different.For HIV seroconversion serum panels,the results of ECLIA and CLIA assays were consistent,and the window period was shortened at least 1 to 5 days compared with ELISA assay.For HIV acute samples,all were HIV positive by ECLIA or CLIA assay,but for ELISA assay,94.6% was positive.For samples before seroconversion,ECLIA and CLIA assay had the same sensitivity (93.5%),which is superior to ELISA assay (71.0%) (x2 =5.14,P <0.05).Conclusion The ability of detecting HIV in the window period was different for each assay.The results of ECLIA and CLIA assay are consistent,superior to ELISA assay.

20.
Article in Chinese | WPRIM | ID: wpr-467100

ABSTRACT

Objective: To investigate the effect of chloride concentration on the corrosion of Co-Cr alloy and pure Ti in a simulated oral environment. Methods: The electrochemical corrosion tests of pure Ti and Co-Cr alloy were carried out in neutral artiifcial saliva solutions with different NaCl concentrations (0.9%, 2.0%, and 3.0%). hTe morphologies of corroded surface for pure Ti and Co-Cr alloy were observed by scanning electron microscope (SEM). Results: hTe changes in the self-corrosion potentials (Ecorr) for pure Ti and Co-Cr alloy in three kinds of artificial saliva solutions was not obvious. However, the self-corrosion current densities (Icorr) of pure Ti were much lower than those of Co-Cr. TheIcorr of Co-Cr alloy increased in a concentration-dependent manner of NaCl, whereas the breakdown potential (Eb) of Co-Cr alloy decreased in a concentration-dependent manner. hTe potential ranged for the breakdown of oxide film (Ev) was shortened in a concentration-dependent manner of NaCl. There was no obviousdifference in theIcorr of pure Ti with different concentrations of NaCl. hTe breakdown potential was not seen according to the polarization curves. Conclusion: In a certain range, the increase of the concentration of Cl- leads to accelerate the corrosion behavior of Co-Cr alloy, but it does not affect pure Ti.

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