Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
1.
Nanotechnology ; 32(19): 195208, 2021 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-33503597

RESUMO

Highly luminescent all-inorganic cesium lead bromide (CsPbBr3) perovskite quantum dots (QDs) have been extensively used as a photosensitizer in optoelectronic devices, while p-type small-organic-molecule copper phthalocyanine (CuPc) is also widely used as a photoactive material in solar cells, organic field-effect transistors (OFETs), etc. In this paper, we report the preparation of a CsPbBr3-QDs/CuPc heterostructure to study the effect of CsPbBr3-QDs on CuPc. The optical properties of both CuPc and the QDs/CuPc heterostructure were compared and contrasted using UV-vis absorbance and photoluminescence (PL) measurements. Furthermore, to study their electronic and charge transfer features, we fabricated field-effect transistors (FETs) on both pristine CuPc and QDs/CuPc heterostructure thin films and studied their photoresponsive electrical characteristics. Both pristine and QDs/CuPc-based FETs showed an enhancement in current and carrier mobility under illumination. The enhancement in the current and carrier mobility of the QDs/CuPc-based FETs is due to a large number of photoexcited charge carriers. We also observed that the current and carrier mobility in the QDs/CuPc heterostructure-based FET were lower than those of the pristine CuPc-based FET. This can be explained by the n-type doping effect of CsPbBr3 QDs on CuPc, which reduces the accumulation of holes in the active p-channel near the insulating layer and causes charge to be transferred from the QDs to the CuPc. Thus, we have observed a charge transfer effect in the CsPbBr3 QDs/CuPc heterostructure, which can be used in optoelectronic devices.

2.
Water Sci Technol ; 80(11): 2079-2090, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32198326

RESUMO

The paper describes briefly the process performance and the reuse potential of a laboratory scale wastewater treatment system. The treatment involves enhanced primary treatment of Vellore Institute of Technology (VIT) campus sewage using ferric chloride as a coagulant, anaerobic digestion of coagulated organics, and biofilm aerobic process. The treated effluent after disinfection (using sunlight and chlorine) was used for irrigation of Tagetes erecta (marigold) plants and the plant growth parameters were evaluated for a life span of 3 months. In the primary treatment, an optimum ferric chloride dose of 30 mg/L could remove turbidity, chemical oxygen demand (COD), biochemical oxygen demand (BOD), and bacterial count (Escherichia coli) of 69%, 60%, 77%, and 55%, respectively. The coagulated organics could digest in a 25 L anaerobic reactor effectively with methane content in biogas varied between 50 and 60% and enhanced volatile suspended solids (VSS) reduction up to 70%. Sunlight based photo-oxidation followed chlorine disinfection saved 50% of the chlorine dose required for disinfection and treated effluent was fit for reuse. The results of growth parameters for Tagetes erecta plants indicate that anaerobically digested sludge is an excellent soil conditioner cum nutrient supplier. The results of this study exhibit a promising reuse potential of a decentralized wastewater treatment system and needs to be promoted for field scale applications.


Assuntos
Esgotos , Águas Residuárias , Anaerobiose , Análise da Demanda Biológica de Oxigênio , Reatores Biológicos , Desinfecção , Metano , Eliminação de Resíduos Líquidos
3.
Opt Express ; 25(8): A311-A322, 2017 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-28437918

RESUMO

A key challenge in photovoltaics today is to develop cell technologies with both higher efficiencies and lower fabrication costs than incumbent crystalline silicon (c-Si) single-junction cells. While tandem cells have higher efficiencies than c-Si alone, it is generally challenging to find a low-cost, high-performance material to pair with c-Si. However, the recent emergence of 22% efficient perovskite photovoltaics has created a tremendous opportunity for high-performance, low-cost perovskite / crystalline silicon tandem photovoltaic cells. Nonetheless, two key challenges remain. First, integrating perovskites into tandem structures has not yet been demonstrated to yield performance exceeding commercially available crystalline silicon modules. Second, the stability of perovskites is inconsistent with the needs of most end-users, who install photovoltaic modules to produce power for 25 years or more. Making these cells viable thus requires innovation in materials processing, device design, fabrication, and yield. We will address these two gaps in the photovoltaic literature by investigating new types of 2D perovskite materials with n-butylammonium spacer layers, and integrating these materials into bifacial tandem solar cells providing at least 30% normalized power production. We find that an optimized 2D perovskite ((BA)2(MA)3(Sn0.6Pb0.4)4I13)/silicon bifacial tandem cell, given a globally average albedo of 30%, yields a normalized power production of 30.31%, which should be stable for extended time periods without further change in materials or encapsulation.

4.
ScientificWorldJournal ; 2014: 362351, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24672310

RESUMO

The objective of this investigation is to analyze the effect of unsteadiness on the mixed convection boundary layer flow of micropolar fluid over a permeable shrinking sheet in the presence of viscous dissipation. At the sheet a variable distribution of suction is assumed. The unsteadiness in the flow and temperature fields is caused by the time dependence of the shrinking velocity and surface temperature. With the aid of similarity transformations, the governing partial differential equations are transformed into a set of nonlinear ordinary differential equations, which are solved numerically, using variational finite element method. The influence of important physical parameters, namely, suction parameter, unsteadiness parameter, buoyancy parameter and Eckert number on the velocity, microrotation, and temperature functions is investigated and analyzed with the help of their graphical representations. Additionally skin friction and the rate of heat transfer have also been computed. Under special conditions, an exact solution for the flow velocity is compared with the numerical results obtained by finite element method. An excellent agreement is observed for the two sets of solutions. Furthermore, to verify the convergence of numerical results, calculations are conducted with increasing number of elements.


Assuntos
Análise de Elementos Finitos , Modelos Teóricos , Porosidade
5.
Nutrients ; 16(6)2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38542811

RESUMO

This paper explores the multifaceted nature of ß-glucan, a notable dietary fiber (DF) with extensive applications. Beginning with an in-depth examination of its intricate polysaccharide structure, the discussion extends to diverse sources like oats, barley, mushrooms, and yeast, emphasizing their unique compositions. The absorption and metabolism of ß-glucan in the human body are scrutinized, emphasizing its potential health benefits. Extraction and purification processes for high-quality ß-glucan in food, pharmaceuticals, and cosmetics are outlined. The paper underscores ß-glucan's biofunctional roles in immune modulation, cholesterol regulation, and gastrointestinal health, supported by clinical studies. The review discusses global trade dynamics by tracing its evolution from a niche ingredient to a global commodity. In summary, it offers a comprehensive scientific perspective on ß-glucan, serving as a valuable resource for researchers, professionals, and industries exploring its potential in the dietary fiber landscape.


Assuntos
beta-Glucanas , Humanos , beta-Glucanas/química , Disponibilidade Biológica , Fibras na Dieta , Colesterol , Saccharomyces cerevisiae , Avena/química
6.
ACS Omega ; 5(14): 8251-8257, 2020 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-32309735

RESUMO

In India, the major crop is wheat. Its production is severely hampered by seed-borne diseases such as smut and bunt which are responsible for the reduction of crop yield with poor grain quality. In the current study, an attempt was made to prepare a photoluminescence (PL)-based immunosensor for early detection of Karnal bunt (KB) disease. The KB disease-causing pathogen Tilletia indica was detected using functionalized diatom frustules as a sensing platform. The teliospore-covered platform, on exposure to light, showed enhanced intensity of PL in comparison to control. This response was directly proportional to the concentration of spores. For the development of a stable frustule-based immunosensor platform, gluteraldehyde was added for the covalent immobilization of the T. indica antibody onto amine-functionalized diatom substrates. Frustules of diatom consisting of a nanoporous three-dimensional biogenic silica material exhibit a unique property of emitting strong, visible blue PL under ultraviolet (UV) excitation. PL studies were done to reveal the specificity and binding of the conjugated diatom platform that will distinguish between the T. indica (complementary) and A. niger (noncomplementary) antigens. Four times better intensity of PL was observed against the complementary one in comparison to a noncomplementary setup (control). The immunocomplex frustule-based platform serves as a suitable sensor platform for early detection of KB.

7.
J Nanosci Nanotechnol ; 9(9): 5329-34, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19928223

RESUMO

Highly monodispersed, undoped and doped with Mn2+, binary and ternary (CdS, ZnS, Cd(1-x)Zn(x)S) compound semiconductor nanocrystals have been synthesized by co-precipitation method using citric acid as a stabilizer. As prepared sample are characterized by X-ray diffraction, Small angle X-ray scattering, Transmission electron microscope, Optical absorption and Photoluminescence spectroscopy, for their optical and structural properties. X-ray diffraction, Small angle X-ray scattering and Transmission electron microscope results confirm the preparation of monodispersed nanocrystals. Photoluminescence studies show a significant blue shift in the wavelength with an increasing concentration of Zn in alloy nanocrystals.


Assuntos
Sulfetos , Zinco , Luminescência , Nanopartículas/química , Sulfetos/química , Difração de Raios X , Zinco/química , Compostos de Zinco/química
8.
Water Sci Technol ; 58(1): 7-12, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18653930

RESUMO

The present study aimed mainly for the development of a wastewater treatment system incorporating enhanced primary treatment, anaerobic digestion of coagulated organics, biofilm aerobic process for the removal of soluble organics and disinfection of treated water. An attempt was also made to study the reuse potential of treated water for irrigation and use of digested sludge as soil conditioner by growing marigold plants. Ferric chloride dose of 30 mg/l was found to be the optimum dose for enhanced primary treatment with removals of COD and BOD to the extent of 60% and 77%, respectively. Efficient anaerobic digestion of ferric coagulated sludge was performed at 7 days hydraulic retention time (HRT). Upflow aerobic fixed film reactor (UAFFR) was very efficient in removals of COD/BOD in the organic loading rate (OLR) range of 0.25 to 3 kg COD/m(3)/day with COD and BOD removals in the range 65-90 and 82-96, respectively. Photo-oxidation followed by disinfection saved 50% of chlorine dose required for disinfection of treated effluent and treated water was found to be suitable for irrigation. The result also indicated that anaerobically digested sludge may be an excellent soil conditioner. From the results of this study, it is possible to conclude that the developed wastewater treatment system is an attractive ecologically sustainable alternative for sewage treatment from institutional/industrial/residential campuses.


Assuntos
Eliminação de Resíduos Líquidos/normas , Aerobiose , Biofilmes , Reatores Biológicos , Desinfecção/instrumentação , Desinfecção/métodos , Ecossistema , Resíduos Industriais , Cinética , Oxirredução , Fotoquímica , Esgotos , Eliminação de Resíduos Líquidos/instrumentação , Eliminação de Resíduos Líquidos/métodos , Purificação da Água/instrumentação , Purificação da Água/métodos , Purificação da Água/normas
9.
Appl Biochem Biotechnol ; 185(1): 34-41, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29082475

RESUMO

Euryale ferox is native to Southeast Asia and China, and it is one of the important aquatic food crops propagated mostly in eastern part of India. The aim of the present study was to characterize and evaluate the genetic diversity of ex situ collections of E. ferox germplasm from different geographical states of India using microsatellite (simple sequence repeats (SSRs)) markers. Ten SSR markers were analyzed to assess DNA fingerprinting and genetic diversity of 16 cultivated germplasm of E. ferox. Total 37 polymorphic alleles were recorded with an average of 3.7 allele frequency per primer. The polymorphic information content value varied from 0.204 to 0.735 with mean of 0.448. A high range of heterozygosity (Ho 0.228; He 0.512) was detected in the present study. The neighbor-joining (N-J) tree and the principle coordinate analysis showed that the germplasm divided in to three main clusters. The results of the present investigation comply that SSR markers are effective for computing genetic assessment of genetic diversity and similarity with classifying cultivated varieties of E. ferox. Evaluation of genetic diversity among Indian E. ferox germplasm could provide useful information for genetic improvement.


Assuntos
Alelos , Produtos Agrícolas/genética , Impressões Digitais de DNA/métodos , Repetições de Microssatélites , Nymphaeaceae/genética , Polimorfismo Genético
10.
Appl Biochem Biotechnol ; 180(7): 1345-1360, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27364330

RESUMO

Euryale ferox Salisbury is an important aquatic food plant cultivated largely in eastern India. E. ferox is a monotypic genus, and breeding programmes have mostly relied on the variability present in the primary gene pool. Knowledge of the genetic structure of the population is limited, and there are very few reports available on the genetic diversity of E. ferox. In this study, comprehensive research on the genetic diversity of 16 germplasms of E. ferox was carried out using random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) markers. Out of 320 RAPD and 95 ISSR primers screened initially, 61 primers (40 RAPD and 21 ISSR) gave reproducible bands and were selected for further work. Amplification of the 40 RAPD primers gave 533 polymorphic bands with an average of 13.32 polymorphic bands per primer. The percentage of polymorphism ranged from 37.5 to 100, with an average of 88.3 %. The 21 ISSR primers produced 259 bands, of which 214 were polymorphic, with an average of 10.19 polymorphic bands per primer. The percentage of polymorphism using ISSR primers ranged from 50 to 100, with a mean of 82.6 %. Jaccard's coefficient ranged from 0.45 to 0.69 (RAPD), 0.50 to 0.77 (ISSR) and 0.48 to 0.71 (RAPD and ISSR). Molecular characterization of different germplasms of E. ferox not only is essential for its conservation but also can be used in further breeding programmes.


Assuntos
Organismos Aquáticos/genética , Variação Genética , Repetições de Microssatélites/genética , Nymphaeaceae/genética , Técnica de Amplificação ao Acaso de DNA Polimórfico , Sementes/genética , Marcadores Genéticos , Índia , Filogenia , Reação em Cadeia da Polimerase , Análise de Componente Principal
11.
J Cancer Res Ther ; 11(4): 1038, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26881650

RESUMO

Dermatofibrosarcoma protuberans (DFSP) is an uncommon, locally aggressive, soft tissue tumor. Its occurrence over face is very rare. We are presenting a case of giant DFSP over left cheek, which produces oncological, functional and esthetic challenges and deals by multidisciplinary team. We also reviewed the relevant literature in short.


Assuntos
Dermatofibrossarcoma/patologia , Neoplasias Faciais/patologia , Neoplasias Cutâneas/patologia , Dermatofibrossarcoma/cirurgia , Neoplasias Faciais/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Neoplasias Cutâneas/cirurgia
12.
J Surg Tech Case Rep ; 6(2): 55-7, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25598943

RESUMO

Transverse testicular ectopia (TTE) is a rare anomaly in which both testis descend through a single inguinal canal and enter to same hemiscrotum. To the best of our knowledge, we are reporting a new variant of TTE with right inguinal hernia with bilateral pyocoele. In this case, both testes descend separately through corresponding inguinal canal and present in single right scrotum. There is no report of bilateral orchidectomy for this variant of TTE with bilateral pyocoele with calcified necrosed testes. We also describe its embryology and management in brief, and review the previously reported cases.

13.
Appl Biochem Biotechnol ; 166(7): 1723-35, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22367638

RESUMO

Purification and characterization of halotolerant, thermostable alkaline L-glutaminase from a Bacillus sp. LKG-01 (MTCC 10401), isolated from Gangotri region of Uttarakhand Himalaya, is being reported in this paper. Enzyme has been purified 49-fold from cell-free extract with 25% recovery (specific activity 584.2 U/mg protein) by (NH4)2SO4 precipitation followed by anion exchange chromatography and gel filtration. Enzyme has a molecular weight of 66 kDa. L-Glutaminase is most active at pH 11.0 and stable in the pH range 8.0-11.0. Temperature optimum is 70 °C and is completely stable after 3 h pre-incubation at 50 °C. Enzyme reflects more enhanced activity with 1-20% (w/v) NaCl, which is further reduced to 80% when NaCl concentration was increased up to 25%. L-Glutaminase is almost active with K⁺, Zn²âº, and Ni²âº ions and K(m) and V(max) values of 240 µM and 277.77 ± 1.1 U/mg proteins, respectively. Higher specific activity, purification fold, better halo-tolerance, and thermostability would make this enzyme more attractive for food fermentation with respect to other soil microbe derived L-glutaminase reported so far.


Assuntos
Bacillus/enzimologia , Proteínas de Bactérias/isolamento & purificação , Glutaminase/isolamento & purificação , Sulfato de Amônio/química , Proteínas de Bactérias/metabolismo , Cromatografia em Gel , Cromatografia por Troca Iônica , Eletroforese em Gel de Poliacrilamida , Estabilidade Enzimática , Glutaminase/metabolismo , Temperatura Alta , Concentração de Íons de Hidrogênio , Índia , Cinética , Peso Molecular , Filogenia , Tolerância ao Sal , Cloreto de Sódio
14.
Nanoscale Res Lett ; 5(1): 96-102, 2009 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-20652135

RESUMO

Highly luminescent Ag-ion-doped Cd1-xZnxS (0 ≤ x ≤ 1) alloy nanocrystals were successfully synthesized by a novel wet chemical precipitation method. Influence of dopant concentration and the Zn/Cd stoichiometric variations in doped alloy nanocrystals have been investigated. The samples were characterized by X-ray diffraction (XRD) and high resolution transmission electron microscope (HRTEM) to investigate the size and structure of the as prepared nanocrystals. A shift in LO phonon modes from micro-Raman investigations and the elemental analysis from the energy dispersive X-ray analysis (EDAX) confirms the stoichiometry of the final product. The average crystallite size was found increasing from 1.0 to 1.4 nm with gradual increase in Ag doping. It was observed that photoluminescence (PL) intensity corresponding to Ag impurity (570 nm), relative to the other two bands 480 and 520 nm that originates due to native defects, enhanced and showed slight red shift with increasing silver doping. In addition, decrease in the band gap energy of the doped nanocrystals indicates that the introduction of dopant ion in the host material influence the particle size of the nanocrystals. The composition dependent bandgap engineering in CdZnS:Ag was achieved to attain the deliberate color tunability and demonstrated successfully, which are potentially important for white light generation.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA