Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 67
Filtrar
1.
Dalton Trans ; 53(10): 4544-4550, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38348902

RESUMO

The rational design of multiple metal ions into high-entropy oxide electrode material via a single-step hydrothermal process is applicable to the evolution of oxygen molecules (O2) through simple water electrolysis. Their cost-effectiveness, high performance, and durable nature are the key factors of non-precious high-entropy multiple metal-based electrocatalysts, which can be used as replaceable catalysts instead of precious ones. This article reports a low-temperature synthesis of the cauliflower-type morphology of high-entropy amorphous metal oxides, and their electrochemical performances towards the oxygen evolution reaction (OER) are investigated. The multiple metal ion (Mn2+, Fe3+, Co2+, Ni2+, Cu2+) oxide electrode material shows an acceptable oxygen evolution reaction (OER) with an overpotential of 290 mV at a current density of 10 mA cm-2 and a lower Tafel slope value of 85 mV dec-1, respectively. Moreover, the 20 h durability test with negligible change in overpotential shows the efficacy of the modified electrode material in harsh alkaline media. The observed electrochemical results towards the OER correspond to the amorphous nature of the active material that displayed a cauliflower-type morphology, having a large specific surface area (240 m2 g-1) and providing higher electrochemical active sites as well. Consequently, post-stability characterization studies (such as PXRD, FESEM, TEM, and XPS) provide more information for understanding the post-structural and morphological results of the high-entropy amorphous metal oxide.

2.
Comput Intell Neurosci ; 2022: 2218594, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35795744

RESUMO

In this review, we intend to present a complete literature survey on the conception and variants of the recent successful optimization algorithm, Harris Hawk optimizer (HHO), along with an updated set of applications in well-established works. For this purpose, we first present an overview of HHO, including its logic of equations and mathematical model. Next, we focus on reviewing different variants of HHO from the available well-established literature. To provide readers a deep vision and foster the application of the HHO, we review the state-of-the-art improvements of HHO, focusing mainly on fuzzy HHO and a new intuitionistic fuzzy HHO algorithm. We also review the applications of HHO in enhancing machine learning operations and in tackling engineering optimization problems. This survey can cover different aspects of HHO and its future applications to provide a basis for future research in the development of swarm intelligence paths and the use of HHO for real-world problems.


Assuntos
Inteligência Artificial , Falconiformes , Algoritmos , Animais , Aprendizado de Máquina , Modelos Teóricos
3.
Comput Intell Neurosci ; 2022: 1871841, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35615545

RESUMO

Cancer is a wide category of diseases that is caused by the abnormal, uncontrollable growth of cells, and it is the second leading cause of death globally. Screening, early diagnosis, and prediction of recurrence give patients the best possible chance for successful treatment. However, these tests can be expensive and invasive and the results have to be interpreted by experts. Genetic algorithms (GAs) are metaheuristics that belong to the class of evolutionary algorithms. GAs can find the optimal or near-optimal solutions in huge, difficult search spaces and are widely used for search and optimization. This makes them ideal for detecting cancer by creating models to interpret the results of tests, especially noninvasive. In this article, we have comprehensively reviewed the existing literature, analyzed them critically, provided a comparative analysis of the state-of-the-art techniques, and identified the future challenges in the development of such techniques by medical professionals.


Assuntos
Algoritmos , Neoplasias , Evolução Biológica , Humanos , Neoplasias/diagnóstico , Neoplasias/genética
4.
Appl Radiat Isot ; 70(4): 612-6, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22204786

RESUMO

Coal and coal ash samples were characterized by particle induced X-ray emission spectroscopic technique. Sixteen elements, namely K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, As, Rb, Sr, Y and Pb were quantified in this study. Elements like K, Ca, Ti and Fe were present as major elements, whereas, other elements like V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Rb, Sr and Pb were present in trace level. The enrichment ratio of different ash samples with respect to coal were also estimated and discussed.


Assuntos
Cinza de Carvão/análise , Carvão Mineral/análise , Espectrometria por Raios X/métodos , Elementos Químicos
5.
J Indian Assoc Pediatr Surg ; 15(3): 108-9, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21124669

RESUMO

This study reports four children who developed complete stricture of pylorus and antrum of the stomach following accidental ingestion of corrosive agent (toilet cleaner).

6.
Afr J Paediatr Surg ; 7(3): 156-8, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20859019

RESUMO

BACKGROUND: Colostomy site, which is a potentially contaminated wound, is traditionally closed with interrupted skin stitches and placement of intraperitoneal or parietal or both drains; often with poor cosmetic outcome in our country. This study aims at prospective evaluation of colostomy closure wounds by different techniques. PATIENTS AND METHODS: This study was carried out in all infants and children with colostomy (for different pathologies) admitted for colostomy closure in our institute from August 1, 2006 to February 29, 2008. Patients were divided into two groups: Group A with colostomy closure without any drain and subcuticular skin closure and Group B with colostomy closure with both intraperitoneal and parietal drain and interrupted skin closure. Patient's details, including age, sex, body weight, diagnosis, preoperative bowel preparation, peroperative antibiotics, postoperative wound infection, anastomotic leaks, duration of hospitalisation and postoperative follow-up for wound assessment, were recorded. By the end of February 2008, 151 cases of colostomy closure were recorded, 70 in Group A and 81 in Group B. RESULTS: Statistical analysis of the data showed no statistically significant difference in wound infection and anastomotic leak between the two groups. On postoperative follow-up, wound assessment showed significantly better cosmesis in the no drain subcuticular group. CONCLUSION: This study shows that closing colostomies without any drain and subcuticular skin closure does not result in any increased incidence of wound infection and has better cosmetic results.


Assuntos
Anti-Infecciosos/uso terapêutico , Colostomia/efeitos adversos , Infecção da Ferida Cirúrgica/tratamento farmacológico , Criança , Pré-Escolar , Colostomia/métodos , Países em Desenvolvimento , Drenagem , Feminino , Seguimentos , Humanos , Incidência , Índia/epidemiologia , Lactente , Masculino , Estudos Prospectivos , Distribuição por Sexo , Infecção da Ferida Cirúrgica/epidemiologia , Infecção da Ferida Cirúrgica/etiologia , Técnicas de Sutura , Resultado do Tratamento , Cicatrização
7.
Dalton Trans ; 39(38): 9108-11, 2010 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-20733994

RESUMO

Precipitation of boehmite (Al(2)O(3)·H(2)O) instead of gibbsite (Al(2)O(3)·3H(2)O) from sodium aluminate liquor can be an energy saving option for alumina production. Gibbsite is stable at precipitation temperature lower than 90 °C. Thus when boehmite is precipitated below 90 °C it is always accompanied with a gibbsite phase. However, the addition of certain organic additives favours precipitation of a monophase product i.e. boehmite at a temperature lower than 90 °C. At a temperature as low as 60 °C additives like tartaric acid, xylose and glucose could favour the precipitation of single phase boehmite precipitation. The role of the additive is proposed to be complete inhibition of gibbsite formation and facilitation of boehmite nucleation through different extent of complex formation by multidentate ligands.

8.
Appl Radiat Isot ; 68(3): 454-8, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20053568

RESUMO

Elemental analysis of nine Indian silver coins during British rule was carried out by proton induced X-ray emission spectroscopy. Eight elements, namely Cr, Fe, Ni, Cu, Zn, As, Ag, and Pb were determined in the present study. Ag and Cu were found to be the major elements, Zn was the only minor element and all other elements are present at the trace level. The variation of the elemental concentration may be due to the use of different ores for making coins.

9.
J Indian Med Assoc ; 108(10): 694-6, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21510560

RESUMO

Gastric teratoma is a rare lesion seen most often in male infants. This patient, aged one year, female was having a massive benign gastric teratoma. The size of the tumour was 22 cm x 10 cm x 8 cm and weighted 2.250 kg making it one of the largest gastric teratoma. The tumour was removed by surgery. Histopathology revealed presence of all 3 elements in the form of skin, cartilage, fibrofatty tissue, blood vessels and gland with tall columnar epithelium. Postoperative period was uneventful.


Assuntos
Neoplasias Gástricas/diagnóstico , Neoplasias Gástricas/cirurgia , Teratoma/diagnóstico , Teratoma/cirurgia , Diagnóstico Diferencial , Diagnóstico por Imagem , Feminino , Humanos , Lactente , Neoplasias Gástricas/patologia , Teratoma/patologia
10.
Biogerontology ; 7(2): 81-9, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16802111

RESUMO

This study investigated the influence of chronically administered curcumin on normal ageing-related parameters: lipid peroxidation, lipofuscin concentration and intraneuronal lipofuscin accumulation, activities of the enzymes superoxide dismutase (SOD), glutathione peroxidase (GPx), and Na(+), K(+), -adenosine triphosphatase (Na(+), K(+), -ATPase) in different brain regions (cerebral cortex, hippocampus, cerebellum and medulla) of 6- and 24-month-old rats. In normal ageing, lipid peroxidation and lipofuscin concentration were found to increase with ageing, the activities of SOD, GPx and Na(+), K(+), -ATPase, however, decreased with ageing. Chronic curcumin treatment of both 6 and 24 months old rats resulted in significant decreases in lipid peroxide and the lipofuscin contents in brain regions, the activities of SOD, GPx and Na(+), K(+), -ATPase however, showed significant increase in various brain regions. The present study, thus, demonstrated the antioxidative, antilipofusinogenesic and anti-ageing effects of curcumin in the brain.


Assuntos
Envelhecimento/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Curcumina/farmacologia , Inibidores Enzimáticos/farmacologia , Fármacos Neuroprotetores/farmacologia , Envelhecimento/metabolismo , Animais , Encéfalo/metabolismo , Cerebelo/efeitos dos fármacos , Cerebelo/metabolismo , Glutationa Peroxidase/metabolismo , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Lipofuscina/metabolismo , Masculino , Bulbo/efeitos dos fármacos , Bulbo/metabolismo , Lobo Parietal/efeitos dos fármacos , Lobo Parietal/metabolismo , Ratos , Ratos Wistar , ATPase Trocadora de Sódio-Potássio/metabolismo , Superóxido Dismutase/metabolismo
11.
Planta ; 223(1): 46-56, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16160842

RESUMO

The concept of using higher plants to maintain a sustainable life support system for humans during long-duration space missions is dependent upon photosynthesis. The effects of extended exposure to microgravity on the development and functioning of photosynthesis at the leaf and stand levels were examined onboard the International Space Station (ISS). The PESTO (Photosynthesis Experiment Systems Testing and Operations) experiment was the first long-term replicated test to obtain direct measurements of canopy photosynthesis from space under well-controlled conditions. The PESTO experiment consisted of a series of 21-24 day growth cycles of Triticum aestivum L. cv. USU Apogee onboard ISS. Single leaf measurements showed no differences in photosynthetic activity at the moderate (up to 600 micromol m(-2) s(-1)) light levels, but reductions in whole chain electron transport, PSII, and PSI activities were measured under saturating light (>2,000 micromol m(-2) s(-1)) and CO(2) (4000 micromol mol(-1)) conditions in the microgravity-grown plants. Canopy level photosynthetic rates of plants developing in microgravity at approximately 280 micromol m(-2) s(-1) were not different from ground controls. The wheat canopy had apparently adapted to the microgravity environment since the CO(2) compensation (121 vs. 118 micromol mol(-1)) and PPF compensation (85 vs. 81 micromol m(-2) s(-1)) of the flight and ground treatments were similar. The reduction in whole chain electron transport (13%), PSII (13%), and PSI (16%) activities observed under saturating light conditions suggests that microgravity-induced responses at the canopy level may occur at higher PPF intensity.


Assuntos
Fotossíntese , Triticum/fisiologia , Ausência de Peso , Dióxido de Carbono , Clorofila/metabolismo , Transporte de Elétrons , Sistemas de Manutenção da Vida , Luz , Complexo de Proteína do Fotossistema I/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/metabolismo , Voo Espacial , Tilacoides/metabolismo , Triticum/crescimento & desenvolvimento , Triticum/metabolismo
12.
Photosynth Res ; 81(1): 31-40, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-16328845

RESUMO

The present study was conducted to observe the role of the root-shoot transition zone in the development of PS I and PS II in red light. The development of PS II and PS I was severely inhibited when root-shoot transition zones of wheat seedlings were exposed to red light (670 nm) of intensity 500 micromol m(-2) s(-1). Chlorophyll biosynthesis was also inhibited in these seedlings. Most of the PS I and PS II proteins (D1, LHCPII, CP47, OEC33) and their transcript levels were severely inhibited but cyt b6f complex proteins were only partially inhibited. Protein and transcript levels of Rubisco large subunit and protochlorophyllide (Pchlide) biosynthesis were also severely inhibited in these seedlings. When incubated in the dark with or without the precursor of chlorophyll biosynthesis ALA, these plants accumulated most of the Pchlide, as non-phototransformable Pchlide, suggesting low activity of NADPH:protochlorophyllide oxidoreductase (EC 1.6.99.1) in these plants. These effects were not observed when the seedlings were grown in red light with their root-shoot transition zones covered. These results suggest that the root-shoot transition zone plays an important role in the overall greening process involving transcription and translation of photosynthetic genes.

14.
Indian J Biochem Biophys ; 37(6): 498-505, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11355639

RESUMO

Treatment of diphenyl ether herbicide acifluorfen-Na (AF-Na) to intact cucumber (Cucumis sativus L cv Poinsette) seedlings induced overaccumulation of protoporphyrin IX in light (75 mumole m-2 s-1). The extra-plastidic protoporphyrin IX accumulated during the light exposure disappeared within two hours of transfer of acifluorofen-treated seedlings to darkness. The dark disappearance was due to re-entry of migrated protoporphyrin IX into the plastid and its subsequent conversion to protochlorophyllide. In light, protoporphyrin IX acted as a photosensitizer and caused generation of active oxygen species. The latter caused damage to the cellular membranes by peroxidation of membrane lipids that resulted in production of malondialdehyde. Damage to the plastidic membranes resulted in damage to photosystem I and photosystem II reactions. Dark-incubation of herbicide-sprayed plants before their exposure to light enhanced photodynamic damage due to diffusion of the herbicide to the site of action. Compared to control, in treated samples the cation-induced increases in variable fluorescence/maximum fluorescence ratio and increase in photosystem II activity was lower due to reduced grana stacking in herbicide-treated and light-exposed plants.


Assuntos
Cucumis sativus/efeitos dos fármacos , Herbicidas/farmacologia , Nitrobenzoatos/farmacologia , Estresse Oxidativo , Cucumis sativus/metabolismo , Protoporfirinas/farmacologia
15.
Planta ; 212(1): 52-9, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11219583

RESUMO

Subplastidic preparations from cotyledons of cucumber (Cucumis sativus L.) were tested for their ability to synthesize protoporphyrin IX from the substrate 5-aminolevulinic acid. Envelope or thylakoid membranes failed to synthesize protoporphyrin IX from the substrate 5-aminolevulinic acid. Stromal preparations synthesized a very low amount of protoporphyrin IX. In a reconstitution experiment using stroma + envelope membranes, protoporphyrin IX synthesis from 5-aminolevulinic acid was enhanced by 660% over that of stroma alone. However, when thylakoids were added to the stroma + envelope mixture, protoporphyrin IX synthesis from 5-aminolevulinic acid was completely inhibited. In the reconstituted stroma + envelope membrane mixture, the reducing agent dithiothreitol enhanced the protoporphyrin IX-synthesizing ability and completely abolished the inhibition of protoporphyrin IX synthesis by thylakoids. This suggested that the oxidizing agents usually associated with the thylakoid membranes inhibited protoporphyrin IX biosynthesis and the inhibition was alleviated by the reducing power of dithiothreitol. This study exposes the weakness of in vitro reconstitution experiments in mimicking the in vivo-conditions. Addition of ATP stimulated protoporphyrin IX synthesis by 50% in the supernatant fraction of chloroplast lysate. This ATP-induced stimulation of protoporphyrin IX synthesis was due to the enhancement of the activities of uroporphyrinogen decarboxylase and protoporphyrinogen oxidase, involved in tetrapyrrole biosynthesis. The ATP-induced stimulation of porphyrinogen oxidase activity was an energy-dependent reaction.


Assuntos
Trifosfato de Adenosina/metabolismo , Cucumis sativus/metabolismo , Oxirredutases atuantes sobre Doadores de Grupo CH-CH , Plastídeos/metabolismo , Protoporfirinas/biossíntese , Adenina/metabolismo , Adenosina/metabolismo , Monofosfato de Adenosina/metabolismo , Ácido Aminolevulínico/metabolismo , Fracionamento Químico , Cloroplastos/metabolismo , Ditiotreitol/metabolismo , Ácidos Hidroxâmicos/metabolismo , Hidroximetilbilano Sintase/metabolismo , Oxirredutases/metabolismo , Sintase do Porfobilinogênio/metabolismo , Protoporfirinogênio Oxidase , Tilacoides/metabolismo
16.
Plant Physiol ; 117(3): 851-8, 1998 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9662527

RESUMO

Chlorophyll (Chl) biosynthesis in chill (7 degreesC)- and heat (42 degreesC)-stressed cucumber (Cucumis sativus L. cv poinsette) seedlings was affected by 90 and 60%, respectively. Inhibition of Chl biosynthesis was partly due to impairment of 5-aminolevulinic acid biosynthesis both in chill- (78%) and heat-stress (70%) conditions. Protochlorophyllide (Pchlide) synthesis in chill- and heat-stressed seedlings was inhibited by 90 and 70%, respectively. Severe inhibition of Pchlide biosynthesis in chill-stressed seedlings was caused by inactivations of all of the enzymes involved in protoporphyrin IX (Proto IX) synthesis, Mg-chelatase, and Mg-protoporphyrin IX monoester cyclase. In heat-stressed seedlings, although 5-aminolevulinic acid dehydratase and porphobilinogen deaminase were partially inhibited, one of the porphyrinogen-oxidizing enzymes, uroporphyrinogen decarboxylase, was stimulated and coproporphyrinogen oxidase and protoporphyrinogen oxidase were not substantially affected, which demonstrated that protoporphyrin IX synthesis was relatively more resistant to heat stress. Pchlide oxidoreductase, which is responsible for phototransformation of Pchlide to chlorophyllide, increased in heat-stress conditions by 46% over that of the control seedlings, whereas it was not affected in chill-stressed seedlings. In wheat (Triticum aestivum L. cv HD2329) seedlings porphobilinogen deaminase, Pchlide synthesis, and Pchlide oxidoreductase were affected in a manner similar to that of cucumber, suggesting that temperature stress has a broadly similar effect on Chl biosynthetic enzymes in both cucumber and wheat.

17.
Diabetes Metab Rev ; 14(2): 153-70, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9679668

RESUMO

Fibrocalculous pancreatic diabetes (FCPD) is a unique form of diabetes secondary to chronic pancreatitis seen in developing countries of the world associated with either overt protein-calorie malnutrition or, more likely, with deficiency of certain micronutrients. FCPD affects young individuals and runs an aggressive course to reach the endpoints of diabetes, pancreatic calculi and exocrine pancreatic dysfunction (steatorrhoea) in the majority of cases. There are characteristic features of FCPD radiologically, ultrasonographically, on endoscopic retrograde cholangiopancreatography and on histopathology which distinguish it from chronic pancreatitis of other aetiologies seen in temperate zones, e.g. alcoholic chronic pancreatitis. Although a secondary form of diabetes, specific diabetes-related complications like retinopathy and nephropathy do occur in FCPD. There appears to be a high risk of developing pancreatic carcinoma. Although the aetiology of FCPD is still unclear, the role of micronutrient (antioxidant) deficiency is emerging as a possible aetiological or predisposing factor. The contribution of genetic factors and environmental toxins, e.g. cyanogenic glycosides or other nutritional/toxic factors, merit further study. Studies on FCPD, a good model of a secondary form of diabetes, could lead to improved understanding of other primary forms of diabetes as well. If the underlying aetiological factors are identified, it may also be possible to prevent this type of diabetes.


Assuntos
Diabetes Mellitus/etiologia , Pancreatite/complicações , Adulto , Diabetes Mellitus/patologia , Feminino , Humanos , Masculino , Manihot/efeitos adversos , Distúrbios Nutricionais/complicações , Distúrbios Nutricionais/patologia , Pâncreas/patologia , Pancreatite/patologia , Tomografia Computadorizada por Raios X
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...