Base de dados : LILACS
Pesquisa : E05.196.867.335 [Categoria DeCS]
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Texto completo SciELO Chile
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Id: biblio-950872
Autor: Kargupta, Roli; Puttaswamy, Sachidevi; Lee, Aiden J; Butler, Timothy E; Li, Zhongyu; Chakraborty, Sounak; Sengupta, Shramik.
Título: Rapid culture-based detection of living mycobacteria using microchannel electrical impedance spectroscopy (m-EIS)
Fonte: Biol. Res;50:21, 2017. tab, graf.
Idioma: en.
Projeto: NIH.
Resumo: BACKGROUND: Multiple techniques exist for detecting Mycobacteria, each having its own advantages and drawbacks. Among them, automated culture-based systems like the BACTEC-MGIT™ are popular because they are inexpensive, reliable and highly accurate. However, they have a relatively long "time-to-detection" (TTD). Hence, a method that retains the reliability and low-cost of the MGIT system, while reducing TTD would be highly desirable. METHODS: Living bacterial cells possess a membrane potential, on account of which they store charge when subjected to an AC-field. This charge storage (bulk capacitance) can be estimated using impedance measurements at multiple frequencies. An increase in the number of living cells during culture is reflected in an increase in bulk capacitance, and this forms the basis of our detection. M. bovis BCG and M. smegmatis suspensions with differing initial loads are cultured in MGIT media supplemented with OADC and Middlebrook 7H9 media respectively, electrical "scans" taken at regular intervals and the bulk capacitance estimated from the scans. Bulk capacitance estimates at later time-points are statistically compared to the suspension's baseline value. A statistically significant increase is assumed to indicate the presence of proliferating mycobacteria. RESULTS: Our TTDs were 60 and 36 h for M. bovis BCG and 20 and 9 h for M. smegmatis with initial loads of 1000 CFU/ml and 100,000 CFU/ml respectively. The corresponding TTDs for the commercial BACTEC MGIT 960 system were 131 and 84.6 h for M. bovis BCG and 41.7 and 12 h for M smegmatis, respectively. CONCLUSION: Our culture-based detection method using multi-frequency impedance measurements is capable of detecting mycobacteria faster than current commercial systems.
Descritores: Técnicas Bacteriológicas/métodos
Espectroscopia Dielétrica
Mycobacterium/isolamento & purificação
Mycobacterium/crescimento & desenvolvimento
-Fatores de Tempo
Reprodutibilidade dos Testes
Meios de Cultura
Mycobacterium/classificação
Limites: Humanos
Responsável: CL1.1 - Biblioteca Central


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Id: biblio-910617
Autor: Chattopadhyay, Rajat; Mahata, C. R.
Título: A Fundamental Study to Observe Correlation at Molecular Level between Bio-Samples of Patients and Indicated Homoeopathic Medicines
Fonte: Int. j. high dilution res;15(3):11-17, Oct.10 2016.
Idioma: en.
Resumo: Background: 'Like cures like' is the principle that is followed in homoeopathy. Substances whichcause disorder in healthy individuals are used as medicines to treat similar patterns of disorder in sick persons. This article aims to find out whether any similarity picture exists at molecular levelalso that can make a selection of medicines based on scientifically measurable parameters. Method: It consisted of getting frequency domain signatures for the dielectric functions of (i) biofluids(blood serums) of six arthritis patients and (ii) medicines selected for them on the basis of macroscopic similarity. Then, they were compared to find existence/absence of similarity betweenthem.Results: Medicines administered to the six patients were Rhus tox 200cH, Thuja 30cH, Medorrhinum 200cH. The dielectric loss at resonance for the bio-fluids of the patients and themedicines are given in the body of the article.Conclusion: It was observed that the patients who had beneficial results with their medicines havea similarity (resonance frequency matching) in spectral signatures of the two groups of substancesi.e. bio-fluids (blood serum) of patients and the indicated remedies. This similarity was not evidentin the cases where medicines failed to benefit the patients. These results are explorative andenthusiastic, but as the research is limited only to patients with arthritis, generalization could notbe drawn. Further work with more rigor is required to establish the facts and apply generalizationsto other disease condition. In future, this might be a new tool to integrate the fundamental researchwith clinical applications in homeopathy. (AU)
Descritores: Espectroscopia de Ressonância Magnética
Espectroscopia Dielétrica
Biologia Molecular
-FRAUDABDOMINAL INJURIES
Limites: Humanos
Responsável: BR926.1 - Biblioteca Artur de Almeida Rezende Filho


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Id: biblio-972904
Autor: Chatterjee, Ahana; Paul, Biplab Kumar; Kar, Subrata; Das, Sukhen; Basu, Ruma; Bhar, Durga Shankar; Manchanda, Rajkumar; Khurana, Anil Kumar; Nayak, Debadatta; Nandy, Papiya.
Título: Effect of ultrahigh diluted homeopathic medicines on the electrical properties of PVDF-HFP
Fonte: Int. j. high dilution res;15(1):10-17, 2016. ilus, graf.
Idioma: en.
Resumo: In an effort to improve the electrical properties of the electroactive Poly(vinylidene fluoride-hexafluoropropylene) (PVdF-HFP), we introduced a novel and simple approach to synthesize PVDFHFP composite films by incorporating ultrahigh dilutions of two homeopathic medicines Ferrum metallicum (FM) and Zincum oxidatum (ZO) in different potencies. The homeo-PVDF-composite films (HPCF) were synthesized by simple solution casting technique. XRD, FESEM, FTIR studies were performed to check the presence of nanoparticles in the film. The electrical properties of the HPCF samples get enhanced significantly due to the incorporation of the medicines and the effect increases with the increase in potency of the medicines.
Descritores: Homeopatia
Ferrum Metallicum
Zinco
Nanopartículas
Altas Potências
Espectroscopia Dielétrica
-Polímeros
Responsável: BR926.1 - Biblioteca Artur de Almeida Rezende Filho


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Texto completo SciELO Brasil
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Id: lil-777363
Autor: Thomas, Anie; Sridhar, Sathyanarayanan; Aghyarian, Shant; Watkins-curry, Pilanda; Chan, Julia Y; Pozzi, Alessandro; Rodrigues, Danieli C.
Título: Corrosion behavior of zirconia in acidulated phosphate fluoride
Fonte: J. appl. oral sci;24(1):52-60, Jan.-Feb. 2016. graf.
Idioma: en.
Resumo: ABSTRACT Objective The corrosion behavior of zirconia in acidulated phosphate fluoride (APF) representing acidic environments and fluoride treatments was studied. Material and Methods Zirconia rods were immersed in 1.23% and 0.123% APF solutions and maintained at 37°C for determined periods of time. Surfaces of all specimens were imaged using digital microscopy and scanning electron microscopy (SEM). Sample mass and dimensions were measured for mass loss determination. Samples were characterized by powder X-ray diffraction (XRD) to detect changes in crystallinity. A biosensor based on electrochemical impedance spectroscopy (EIS) was used to detect ion dissolution of material into the immersion media. Results Digital microscopy revealed diminishing luster of the materials and SEM showed increased superficial corrosion of zirconia submerged in 1.23% APF. Although no structural change was found, the absorption of salts (sodium phosphate) onto the surface of the materials bathed in 0.123% APF was significant. EIS indicated a greater change of impedance for the immersion solutions with increasing bathing time. Conclusion Immersion of zirconia in APF solutions showed deterioration limited to the surface, not extending to the bulk of the material. Inferences on zirconia performance in acidic oral environment can be elucidated from the study.
Descritores: Fluoreto de Fosfato Acidulado/química
Zircônio/química
-Cerâmica/química
Corrosão
Implantes Dentários
Espectroscopia Dielétrica/métodos
Imersão
Teste de Materiais
Microscopia Eletrônica de Varredura
Propriedades de Superfície/efeitos dos fármacos
Fatores de Tempo
Difração de Raios X/métodos
Responsável: BR1.1 - BIREME


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Ribeiro, Ricardo Faria
Mattos, Maria da Glória Chiarello de
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Id: lil-626302
Autor: Galo, Rodrigo; Ribeiro, Ricardo Faria; Rodrigues, Renata Cristina Silveira; Rocha, Luís Augusto; Mattos, Maria da Glória Chiarello de.
Título: Effects of chemical composition on the corrosion of dental alloys
Fonte: Braz. dent. j;23(2):141-148, Mar.-Apr. 2012. ilus, graf, tab.
Idioma: en.
Resumo: The aim of this study was to determine the effect of the oral environment on the corrosion of dental alloys with different compositions, using electrochemical methods. The corrosion rates were obtained from the current-potential curves and electrochemical impedance spectroscopy (EIS). The effect of artificial saliva on the corrosion of dental alloys was dependent on alloy composition. Dissolution of the ions occurred in all tested dental alloys and the results were strongly dependent on the general alloy composition. Regarding the alloys containing nickel, the Ni-Cr and Ni-Cr-Ti alloys released 0.62 mg/L of Ni on average, while the Co-Cr dental alloy released ions between 0.01 and 0.03 mg/L of Co and Cr, respectively.The open-circuit potential stabilized at a higher level with lower deviation (standard deviation: Ni-Cr-6Ti = 32 mV/SCE and Co-Cr = 54 mV/SCE). The potenciodynamic curves of the dental alloys showed that the Ni-based dental alloy with >70 wt% of Ni had a similar curve and the Co-Cr dental alloy showed a low current density and hence a high resistance to corrosion compared with the Ni-based dental alloys. Some changes in microstructure were observed and this fact influenced the corrosion behavior for the alloys. The lower corrosion resistance also led to greater release of nickel ions to the medium. The quantity of Co ions released from the Co-Cr-Mo alloy was relatively small in the solutions. In addition, the quantity of Cr ions released into the artificial saliva from the Co-Cr alloy was lower than Cr release from the Ni-based dental alloys.

O objetivo deste estudo foi determinar o efeito do ambiente bucal na corrosão de diferentes ligas odontológicas, utilizando métodos eletroquímicos. Os índices de corrosão foram obtidos por meio das curvas de corrente-potencial e impedância eletroquímica (EIS). O efeito de saliva artificial na corrosão de ligas odontológicas foi dependente da composição. A dissolução dos íons ocorreu em todas as amostras e os resultados foram dependentes da composição da liga. Algumas mudanças na microestrutura foram observadas durante o estudo e influenciou o comportamento corrosivo das ligas investigadas. As ligas de Ni-Cr e Ni-Cr-Ti libertaram quantidade de 0,62 mg/L de íons Ni enquanto a liga de Co-Cr liberou entre 0,01 e 0,03 mg/L. As curvas potenciodinâmicas das ligas odontológicas mostraram que as ligas a base >70 wt% de Ni obtiveram curvas similares e a liga de Co-Cr apresentou a menor densidade de corrente e em consequência uma resistência alta a corrosão quando comparada as ligas à base de Ni. A baixa resistência à corrosão também levou a maior libertação de íons de níquel para o meio e a quantidade de Co liberado pela liga de Co-Cr-Mo foi relativamente pequena nas soluções. As quantidades de Cr liberada na saliva artificial pela liga de Co-Cr foi menor que a libertação de Cr pela liga à base de Ni.
Descritores: Corrosão
Ligas Dentárias/química
Saliva Artificial/química
-Espectroscopia Dielétrica
Eletroquímica
Íons
Potenciometria
Propriedades de Superfície
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME



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