Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Colloid Interface Sci ; 576: 476-485, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32485397

RESUMO

The study deals with the hydrothermal growth of a CuCo2O4 hierarchical 3D nanoflower-like array on carbon cloth (CuCo2O4@CC), which is a useful multifunctional electrode. The electrocatalytic oxygen evolution reaction (OER) study of the CuCo2O4@CC electrode shows high durability and good activity in 1 M KOH. As an energy storage electrode, it shows a high specific capacitance of 1438 Fg-1 at 10 mA cm-2 in a 3 M KOH electrolyte. The electrochemical stability of the CuCo2O4@CC electrode was tested for 5000 cycles at 10 mA cm-2, and it showed 98.6% stability. This CuCo2O4@CC electrode produces a capacitance of 10 mA cm-2 at an overpotential of 288 mV for the OER, with a Tafel slope of 64.2 mV dev-1. The electrochemical stability measured at an overpotential of 292 mV for 12 h at 10 mA cm-2 shows good electronic stability in an alkaline medium. The enhanced electrochemical performance of the CuCo2O4@CC electrode may be due to the Cu and Co counterparts in addition to the high surface area. The CuCo2O4@CC electrode is a simple, flexible, and cost-effectivive electrode in both electrocatalytic OER and energy storage applications.

2.
Ultrason Sonochem ; 58: 104663, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31450378

RESUMO

To overcome problem of energy crises, and water pollution, multifunctional nanoflower-like FeCo2O4 is synthesized for energy storage and photocatalysis applications. The nanoflower-like FeCo2O4 possesses charge transportation ability. The nanoflower-like morphology of FeCo2O4 is designed by simple hydrothermal synthesis with use of probe sonicator. The systematic analysis is performed for verify relevance of surface characteristics with electrochemical and photocatalytic properties of FeCo2O4 electrode. FeCo2O4 exhibits hierarchical flower-like nanostructure with high surface area and appropriate pore volume, which increases specific capacitance (Cs) up to 1230 F g-1 with stability up to 5000 cycles. Degradation efficiency of crystal violet using FeCo2O4 photocatalyst is reached up to 94.19% under sunlight irradiation for 160 min.

3.
Ultrason Sonochem ; 56: 290-296, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31101265

RESUMO

The nanostructure of metal oxides attracts great attention in the field of supercapacitors because of fast charge transport process. The hydrothermal method is used for development of NiCo2O4nanostructure on carbon cloth as current collector backbone. The stepwise study of various structural, morphological and electrochemical properties of NiCo2O4electrode is studied. The ultrasonic treatment is used to obtain nanowire-like morphology of NiCo2O4 which exhibits hierarchical nanostructure, which provides surface properties such as high surface area and appropriate pore capacity. NiCo2O4 nanostructure with specific capacitance of 1460 F g-1 with high electrochemical stability of 84% after 3000 cycles in 3 M KOH aqueous electrolyte at 100 mV s-1. The electrochemical property shows NiCo2O4is one of the potential candidates for energy storage application. The specific capacitance and energy density for NiCo2O4@CC//NiCo2O4@CC symmetric supercapacitor device is of 124 F g-1 and 16.18 Wh.kg-1, respectively at current density of 5 mA.

4.
J Indian Med Assoc ; 103(10): 522, 524, 526-7, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16498753

RESUMO

This study was aimed to determine during exercise the maximum related oxygen transport viz, maximum heart rate (max HR), dyspnoeic index (DI), oxygen pulse (O2 pulse), recovery heart rate in an athletic and a non-athletic group. Both study groups were subjected to graded treadmill exercise testing and pulmonary function test (PFT) was done using an electronic spirolyser. Results were compared and analysed. Significantly higher values in athletes were observed as compared to non-athletes regarding the following parameters: VO2 max, V(E) max, delta heart rate and max O2 pulse where resting heart rate, DI at VO2 max and recovery heart rate were lower in athletes while there was no significant change in both the groups in observed value of: MW, BR at VO2 max HR. The observations suggest an overall higher adaptability of the cardiovascular system and the relative refractoriness of the respiratory system to the effects of training and the maximum oxygen consumption in both the groups show similar values as that from otherparts of the country while MW, V(E) max, BR at VO2 and DI at VO2 max differ. A higher delta heart rate in athletes suggests a lesser risk for cardiovascular mortality in this group.


Assuntos
Fenômenos Fisiológicos Cardiovasculares , Consumo de Oxigênio/fisiologia , Esportes/fisiologia , Adolescente , Adulto , Feminino , Frequência Cardíaca/fisiologia , Humanos , Masculino , Oximetria , Aptidão Física/fisiologia
5.
HIV Med ; 5(4): 253-7, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15236613

RESUMO

OBJECTIVES: To assess the spectrum of hepatic disorders in AIDS, liver specimens from 171 patients (155 autopsies and 16 biopsies) were reviewed. METHODS: A retrospective and prospective study of 171 autopsy and biopsy specimens was carried out at a tertiary level hospital in Mumbai, India. RESULTS: Of the patients included in the study, 127 (74%) were male and 44 (26%) were female. The heterosexual route was the predominant mode of HIV transmission, identified in 163 (95%) patients. A total of 99 of 171 patients (58%) showed significant pathological lesions, and the most common pathological processes involving the liver appeared to be secondary to infections. None of our patients showed isolated infectious diseases of the liver. The spectrum of liver diseases identified was as follows: tuberculosis in 70 patients (41%), cryptococcosis in eight (5%), cytomegalovirus infection in six (3%), hepatitis B infection in five (3%), candidiasis in one (0.5%), malaria in one (0.5%), cirrhosis in six (3%), amyloidosis in one (0.5%) and primary hepatic lymphoma in one (0.5%). CONCLUSIONS: AIDS patients were found to have a high prevalence of underlying hepatic abnormalities. The spectrum of disease among patients with AIDS in India differs from that in developed countries. Our results suggest that hepatic tuberculosis is more common in AIDS than previously recognized, and that liver specimens should be examined routinely for the presence of acid-fast bacilli.


Assuntos
Síndrome da Imunodeficiência Adquirida/patologia , Países em Desenvolvimento , Hepatopatias/patologia , Fígado/patologia , Adolescente , Adulto , Amiloidose/patologia , Amiloidose/virologia , Candidíase/patologia , Candidíase/virologia , Criptococose/patologia , Criptococose/virologia , Infecções por Citomegalovirus/patologia , Infecções por Citomegalovirus/virologia , Feminino , Hepatite B/patologia , Hepatite B/virologia , Humanos , Índia , Fígado/microbiologia , Cirrose Hepática/patologia , Cirrose Hepática/virologia , Hepatopatias/microbiologia , Hepatopatias Parasitárias/patologia , Hepatopatias Parasitárias/virologia , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/virologia , Linfoma/patologia , Linfoma/virologia , Malária/patologia , Malária/virologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Estudos Retrospectivos , Tuberculose Hepática/patologia , Tuberculose Hepática/virologia
6.
J Indian Med Assoc ; 101(2): 96-7, 108, 2003 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-12841492

RESUMO

Smoking is a pernicious scourge of the world today. There is paucity of literature on the effect of acute smoking on ventilatory functions. The present work is undertaken to study the effect of 2-5 years of tobacco smoking on ventilatory functions. The study group consisted of 30 male, young, healthy subjects, free from cardiopulmonary diseases and with history of smoking of 2-5 years duration, on an average of 10 cigarettes per day. The control group consisted of 30 age-and sex-matched healthy individuals who had naver smoked tobacco. The ventilatory function tests were carried out using electronic spriolyser. There was a significant lowering of the following parameters in smokers: Vital capacity (VC), inspiratory reserve volume (IRV), inspiratory capacity (IC), forced vital capacity (FVC), forced expiratory volume at the end of first second (FEV1), maximum midexpiratory flow (MMEF), peak expiratory flow (PEF), midexpiratory flow75 (MEF75), maximum voluntary ventilation (MVV). This study shows that 2-5 years of tobacco smoking leads to a definite tendency to narrowing of both the large and the small airways.


Assuntos
Pulmão/fisiopatologia , Fumar/fisiopatologia , Adulto , Estudos de Casos e Controles , Humanos , Masculino , Testes de Função Respiratória
9.
Australas J Dermatol ; 39(3): 177-8, 1998 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9737046

RESUMO

Two well-circumscribed keratotic plaques in an elderly man, one each on symmetrically identical locations over the sides of the buttocks, are described. Clinical and histopathological features supported the diagnosis of benign lichenoid keratosis, which had probably resulted from constant pressure over the site and regressed when this factor was eliminated.


Assuntos
Ceratose/diagnóstico , Erupções Liquenoides/diagnóstico , Idoso , Leitos , Nádegas/patologia , Epiderme/patologia , Humanos , Ceratose/patologia , Erupções Liquenoides/patologia , Masculino , Pressão/efeitos adversos
10.
J Pharm Pharmacol ; 49(5): 491-5, 1997 May.
Artigo em Inglês | MEDLINE | ID: mdl-9178182

RESUMO

The severe toxicity and low therapeutic index of colchicine limit its therapeutic use. Encapsulation in liposomes might reduce these toxic effects. The objective of this study was to determine the factors influencing encapsulation of colchicine in liposomes and to optimize the encapsulation parameters. Colchicine was encapsulated in multilamellar liposomes and large unilamellar liposomes prepared using various phospholipids. The effects of method of preparation, type of vesicle, charge, and concentration of cholesterol on encapsulation of colchicine in liposomes were investigated. Also, stability of colchicine under stress conditions and at various temperatures, and in-vitro release characteristics were determined. A significant difference in encapsulation of colchicine in multilamellar liposomes was observed when prepared by two different methods. Induction of charge on the liposome surface increased encapsulation of colchicine in multilamellar liposomes, but did not affect large unilamellar liposomes. The liposome preparations could withstand simulated transport conditions and frequent changes in temperature. Particle size and concentration of colchicine did not change significantly during storage at various temperatures for six months. In order to retain encapsulated colchicine in liposomes, storage at or below room temperature was found to be suitable. In-vitro release of colchicine from large unilamellar liposomes was biphasic and was influenced by two rate-limiting barriers, the dialysis membrane and the liposome bi-layers. For optimum encapsulation and stability of colchicine liposomes were prepared from a mixture of 1,2-distearoyl-sn-glycero-3-phosphocholine, cholesterol and either stearylamine or dicetyl phosphate.


Assuntos
Colchicina/administração & dosagem , Colchicina/química , Supressores da Gota/química , Supressores da Gota/farmacologia , Cápsulas , Química Farmacêutica/métodos , Colchicina/farmacocinética , Portadores de Fármacos , Sistemas de Liberação de Medicamentos , Estabilidade de Medicamentos , Supressores da Gota/farmacocinética , Lipossomos , Tamanho da Partícula
11.
Mol Reprod Dev ; 46(4): 535-50, 1997 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9094101

RESUMO

Bovine spermatozoa were shown to exhibit rapid regulatory volume decrease (RVD) when exposed to hypotonic saline media. This quinine- and quinidine-sensitive regulatory volume decrease was coincident with K+ release due to stretch-activation of inhibitor-specific presumptive K+ channels. The regulatory volume decrease response was much faster than a similar phenomenon observed in human peripheral blood lymphocytes. Studies on volume changes in different electrolyte and nonelectrolyte media suggested that: (1) this inhibitor-specific channel could also be a nonspecific pore in the spermatozoal membrane for nonelectrolytes below 150 daltons; (2) subpopulations (of nearly equal size) of the spermatozoa differ in the expression of the pore; (3) capacitation abolishes this distinction between subpopulations of spermatozoa; and (4) the general case of RVD for other mammalian spermatozoa was also established.


Assuntos
Canais de Potássio/efeitos dos fármacos , Quinina/farmacologia , Espermatozoides/citologia , Animais , Búfalos , Bovinos , Células Cultivadas , Meios de Cultura , Masculino , Concentração Osmolar , Consumo de Oxigênio/efeitos dos fármacos , Canais de Potássio/metabolismo , Capacitação Espermática/efeitos dos fármacos , Motilidade dos Espermatozoides/efeitos dos fármacos , Espermatozoides/metabolismo
12.
J Pharm Pharmacol ; 48(11): 1112-5, 1996 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-8961156

RESUMO

The purpose of this study was to compare the various methods available to separate non-encapsulated drug from large unilamellar liposomes (LUV). Multilamellar liposomes (MLV) were prepared by thin film hydration using distearoylphosphatidylcholine:cholesterol (2:1 molar ratio). MLVs were passed through a 0.2 micron polycarbonate membrane using an extruder to prepare LUVs. Particle size of liposome preparations was characterized using a submicron particle-size analyser. The non-encapsulated drug was separated by: filtering through Centrifree tubes; passing through gel (Sepharose-4B and Sephadex G-25M); passing through minicolumn; ficoll density gradient; protamine aggregation; or dialysis. The dialysis method was found to be unsuitable for separation of non-encapsulated drug due to equilibration of encapsulated drug as the free drug was dialyzed. The upper limit for lipid concentration was 5 mg mL-1 using the Centrifree method. Separation using gel chromatography led to dilution of liposome preparation. Minicolumn and density gradient techniques did not lead to sample dilution, however the minicolumn method was tedious. The time required for separation of liposomes by protamine aggregation was longer for neutral liposomes. Thus it was concluded that the Centrifree was the fastest method to estimate encapsulation; the density gradient method was ideal to separate non-encapsulated drug; and protamine aggregation was the least expensive method to estimate encapsulation efficiency.


Assuntos
Portadores de Fármacos , Composição de Medicamentos/métodos , Lipossomos/química , Fármacos Anti-HIV/química , Cápsulas , Cromatografia em Gel , Didanosina/química , Humanos
13.
Biochim Biophys Acta ; 1281(2): 189-204, 1996 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-8664318

RESUMO

The role of the permeability barrier of the outer membrane of Pseudomonas was re-evaluated based on the physical theory of molecular sieving in view of its intrinsic antibiotic resistance. We developed a set of analytical procedures based on parametric and non-parametric statistical tests to evaluate, validate and adopt the better among a set of competing non-linear models of diffusion. The molecular mass dependence of uptake of non-electrolytes in bacteria yielded a quantitative measure to distinguish between sieving mechanisms and specific uptake/efflux mechanisms. The experimental data, supported by the physical model of DEAE-Sephadex and various analytical models and extensive simulation of the errors, both in measurement and models, yielded evidence consistent with the relaxation of the outer membrane matrix barrier in Pseudomonas.


Assuntos
Permeabilidade da Membrana Celular , Pseudomonas aeruginosa/fisiologia , Metabolismo dos Carboidratos , Membrana Celular/ultraestrutura , Permeabilidade da Membrana Celular/efeitos dos fármacos , Cetrimônio , Compostos de Cetrimônio/farmacologia , Cromatografia por Troca Iônica , Difusão , Resistência Microbiana a Medicamentos , Escherichia coli/fisiologia , Escherichia coli/ultraestrutura , Matemática , Modelos Biológicos , Peso Molecular , Nefelometria e Turbidimetria , Concentração Osmolar , Pseudomonas aeruginosa/ultraestrutura , Dodecilsulfato de Sódio/farmacologia
14.
J Microencapsul ; 12(3): 229-46, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-7650588

RESUMO

Liposomes have been used as carriers for drugs, toxins, enzymes, proteins/peptides and other bioactive materials there are several liposomal formulations that are being investigated in preclinical and clinical trials. Achieving high encapsulation as well as retention of the encapsulated drug is very important in developing liposomes as drug carriers. A high drug-to-lipid ratio is likely to reduce the cost of formulations and also the risk of lipid-induced toxicity following their injection. Comparison of the encapsulation efficiency of the drug in liposomes with the therapeutic dose indicates whether, in principle, liposomes can be used as a delivery system for that drug. The optimization of the liposomal encapsulation of a drug is usually based on trial and error, rather than on a thorough investigation of the factors affecting it. To obtain optimum encapsulation of a drug into a liposomal preparation, parameters influencing both the liposome and the drug need to be carefully considered during the early stages of development. In this review, factors that affect encapsulation of drugs in liposomes such as liposome size and type, charge on the liposome surface, bilayer rigidity, method of preparation, remote loading, addition of ion pairing, and complexing agents and characteristics of the drug to be encapsulated are discussed.


Assuntos
Portadores de Fármacos , Composição de Medicamentos/métodos , Lipossomos/química , Cápsulas , Bicamadas Lipídicas , Estrutura Molecular , Fosfolipídeos/química , Solubilidade
15.
Anc Sci Life ; 12(3-4): 327-34, 1993 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22556610

RESUMO

The histological features of both the bark and leaf of a poisonous plant H.ferruginea March responsible for contact dermatitis has been reported.

16.
Mutat Res ; 298(1): 17-23, 1992 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-1279412

RESUMO

On exposure to visible light, riboflavin and lumiflavin produced reactive oxygen species such as singlet oxygen and superoxide radicals. The reaction was found to be time- and concentration-dependent. Both riboflavin and lumiflavin, upon illumination, showed mutagenic response in the umu test as well as in the Ames/Salmonella assay with Salmonella typhimurium TA102. The mutagenic response was partially abolished by superoxide dismutase while sodium azide did not have any effect. No mutagenicity was observed if the compounds were not illuminated. The results suggested the involvement of superoxide radicals in light-induced mutagenicity of riboflavin as well as lumiflavin.


Assuntos
Flavinas/toxicidade , Luz/efeitos adversos , Mutagênicos/toxicidade , Riboflavina/toxicidade , Azidas/farmacologia , Relação Dose-Resposta a Droga , Testes de Mutagenicidade , Oxigênio/metabolismo , Salmonella typhimurium , Azida Sódica , Superóxido Dismutase/farmacologia , Superóxidos/metabolismo , Fatores de Tempo , beta-Galactosidase
18.
Acta Microbiol Hung ; 35(2): 93-9, 1988.
Artigo em Inglês | MEDLINE | ID: mdl-3188835

RESUMO

Presence of insecticide-endosulfan, phosalone or permethrin in the growth medium caused concentration dependent inhibition in the vegetative growth of Chlamydomonas reinhardtii algal cells. The rate of inhibition produced by endosulfan was two-fold higher than that of phosalone or permethrin. Endosulfan affected the cell growth completely at 100 times less concentration as compared to that of phosalone or permethrin. Non-dividing cell populations encountered significant losses in cells during their exposure (2 h) to endosulfan and did not show further loss in the 72 h post-treatment period. The populations treated with phosalone exhibited losses of considerable magnitude in the post-treatment period. Permethrin treated non-diving cell populations did not lower the cell number, either after the treatment period (2 h) or the post-treatment period (72 h). However, these populations showed reduced levels of chlorophyll following the exposure of the insecticide and did not display recovery or further reduction in the levels in the post-treatment period. The chlorophyll levels of endosulfan or phosalone treated cell populations remained unaffected. The cells remaining intact after the treatment (2 h) of endosulfan or phosalone exhibited significant decreases in their post treatment vegetative growth abilities. The growth ability of such permethrin exposed cells was similar to that of untreated cells.


Assuntos
Chlamydomonas/efeitos dos fármacos , Endossulfano/farmacologia , Inseticidas/síntese química , Compostos Organotiofosforados/farmacologia , Piretrinas/farmacologia , Contagem de Células , Células Cultivadas , Chlamydomonas/crescimento & desenvolvimento , Chlamydomonas/metabolismo , Clorofila/metabolismo , Inseticidas/farmacologia , Permetrina
19.
Contact Dermatitis ; 17(4): 219-22, 1987 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-3427948

RESUMO

9 of 10 patients who developed dermatitis following contact with Holigarna ferruginea and 5 of 35 asymptomatic volunteers showed a positive patch test reaction to 2% W/V acetone extract of the plant's resinous exudate. 6 albino rats were sensitized following 3 weekly applications of the same extract. Laccol (3-heptadecadienyl catechol) was identified as the active principle in the exudate.


Assuntos
Catecóis/intoxicação , Dermatite de Contato/etiologia , Intoxicação por Plantas/complicações , Adulto , Idoso , Animais , Criança , Feminino , Humanos , Índia , Masculino , Testes do Emplastro , Ratos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...