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1.
J Environ Manage ; 366: 121881, 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-39018861

RESUMO

Coal ash containing significant amount of SiO2 and Al2O3 is utilized as a catalyst substrate for carbon nanotubes (CNTs) synthesis. Three different types of catalysts were made by impregnating coal ash with cobalt, iron, and nickel. These catalysts were used to produce CNTs through pyrolysis of waste polypropylene followed by chemical vapor deposition. The influence of catalyst type and reaction temperature (700, 800 and 900 °C) on CNTs yield and its quality was studied in detail. The produced CNTs were characterized by thermogravimetric analysis (TGA), Raman scattering and electron microscopes (FESEM and HRTEM). The TGA results revealed that the Ni catalyst produced CNTs with highest yield (266 %) compared to those synthesized over and Fe (96 %) and Co (95 %). However, the yield of the CNTs from all three metal impregnated coal ash based catalysts was found to have decreased with increase in reaction temperature. The thermal stability of CNTs obtained over different catalysts followed the order of Fe (570 °C) > Ni (550 °C) > Co (530 °C). Further, the Raman analysis demonstrated that the produced CNTs over different catalysts showed increasing degree of graphitization with the rise in reaction temperature. Additionally, the ID/IG ratios indicated that CNTs produced from Fe catalyst showed highest degree of graphitization followed by Co and Ni. FESEM and HRTEM analysis showed that the coal ash based catalysts produced multiwalled CNTs and the diameter of the CNTs was increasing with the rise in catalysis temperature. Therefore, co-utilization of coal ash and waste plastic for production of high value CNTs can be a sustainable approach to waste management while actively contributing in circular economy.

2.
Sci Rep ; 13(1): 8253, 2023 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-37217776

RESUMO

The propensity of manufacturers to produce goods at affordable cost, with more accuracy, and at a faster rate force them to search for novel solutions, such as deploying robots in place of people in a sector that can accommodate their needs. Welding is one of the most crucial processes in the automotive industry. This process is time-consuming, subject to error, and demands skilled professionals. The robotic application can improve this area of production and quality. Other industries, such as painting and material handling, can also profit from the use of robots. This work describes the fuzzy DC linear servo controller, which functions as a robotic arm actuator. Robots have been widely employed in most productive sectors in recent years, including assembly plates, welding, tasks at higher temperatures, etc. Controlling a robot accurately is a difficult undertaking as a robot is very nonlinear with many joints that are often organized and unstructured. To carry out the effective task, an effective PID control based on fuzzy logic has been employed together with the method of Particle Swarm Optimization (PSO) approach for the estimate of the parameter. This offline technique determines the lowest number of optimal robotic arm control parameters. To verify the controller design with computer simulation, a comparative assessment of controllers is given by means of a fuzzy surveillance controller with PSO which improves the parameter gain to provide a rapid climb, a smaller overflow, no steady condition error signal, and effective torque control of the robot arm.

3.
Environ Monit Assess ; 195(3): 395, 2023 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-36780023

RESUMO

In the present work, the potential of Cephalosporium strain in degrading the pre-treated (ultraviolet irradiation followed by nitric acid treatment) low-density polyethylene and high-density polyethylene films was investigated. Our observations revealed a significant weight reduction of 24.53 ± 0.73% and 18.22 ± 0.31% in pre-treated low-density polyethylene and high-density polyethylene films respectively, after 56 days of incubation with the Cephalosporium strain. Changes in the physicochemical properties of the mineral salt medium (MSM) were studied to assess the extent of biodegradation. The pH of the MSM decreased gradually during the incubation period, whereas its total dissolved solids and conductivity values increased steadily. Fourier transform infrared spectroscopy (FTIR) indicated the formation of hydroxyl and C = C groups in biodegraded low-density polyethylene films, while in the case of biodegraded high-density polyethylene films it indicated the [Formula: see text]CH2 stretching. Furthermore, the thermogravimetric analysis (TGA) revealed an enhancement in the thermal stabilities of both the LDPE and HDPE films post the biodegradation. Modifications in the polymer surface morphologies after UV irradiation, chemical treatment, and biodegradation steps were visualized via scanning electron microscopy (SEM) analysis. All our observations confirm the ability of the Cephalosporium strain in biodegrading the pre-treated LDPE and HDPE films.


Assuntos
Acremonium , Polietileno , Polietileno/química , Acremonium/metabolismo , Monitoramento Ambiental , Biodegradação Ambiental , Espectroscopia de Infravermelho com Transformada de Fourier
4.
Arch Microbiol ; 204(8): 489, 2022 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35835894

RESUMO

Petroleum-based polymers are not susceptible to microorganisms because of its high molecular weight. Acid treatments convert the polymers into a more oxidized form having low molecular weight. The present in-vitro degradation study focuses on the potential of Cephalosporium species to degrade acid-treated polystyrene (PS) and low-density polyethylene (LDPE) films. A weight loss of around 12% and 13% was achieved for PS and LDPE films respectively in eight weeks of treatment with Cephalosporium species. Fourier transform infrared spectroscopy analysis showed the formation of hydroxyl and carbonyl groups in nitric acid treated PS and LDPE films, respectively. Scanning electron microscopy indicated modifications in the surface morphology of PS and LDPE films after chemical and microbial treatment. An increase in crystallinity of pre-treated polymer samples was observed after fungal treatment. The observations of present study confirmed the enzymatic deterioration and assimilation of pre-treated PS and LDPE samples by the microbial species.


Assuntos
Acremonium , Polietileno , Acremonium/metabolismo , Biodegradação Ambiental , Ácido Nítrico , Polietileno/metabolismo , Poliestirenos/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier
5.
Artigo em Inglês | MEDLINE | ID: mdl-35168153

RESUMO

Measurement of drug concentration in biological matrices (such as serum, plasma, blood, urine, and saliva) is important to determine Bioavailability (BA) and/or Bioequivalence (BE) of a drug product which are required during the drug product development and approval process to support applications for new active substances (INDs, NDAs) and generic (ANDAs) drug products to make critical decisions on safety and efficacy. Because of their vital role, bioanalytical methods should be well-characterized, fully validated and documented to yield reliable results. In present work, a simple, specific, high throughput, accurate and sensitive UHPLC-MS/MS method has been developed and validated for quantification of Minoxidil in human plasma. The analyte and the internal standard were extracted from plasma by Liquid-Liquid Extraction using ethyl acetate. The chromatographic separation was achieved on Thermo Hypersil Gold column (4.6x50mm, 5µm) using acetonitrile-0.1% formic acid in water (60:40, v/v) at a flow rate of 0.400 ml/min. Detection by turbospray positive ionization mass spectrometry in the multiple reaction monitoring mode with a mass transition ion-pair of m/z 210.152 → 163.965 (Minoxidil) and m/z 220.267 → 169.089 (Internal Standard-Minoxidil D10) was found to be linear over the concentration range of 1.280 to 151.075 ng/ml. The method was fully validated as per USFDA guidelines and the results were within regulatory limits. The inter and intra-day precision ranged from 5.42 to 9.27% and 2.55-9.42% respectively. The inter and intra-day accuracy ranged from 89.2 to 98.9% and 102-105% respectively. The method was successfully applied to a BE study involving human volunteers.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Minoxidil/sangue , Minoxidil/farmacocinética , Espectrometria de Massas em Tandem/métodos , Adulto , Humanos , Limite de Detecção , Modelos Lineares , Extração Líquido-Líquido , Masculino , Minoxidil/química , Minoxidil/isolamento & purificação , Reprodutibilidade dos Testes
6.
Environ Monit Assess ; 193(8): 513, 2021 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-34302548

RESUMO

The present analysis deals with the ability of Thermomyces lanuginosus to degrade pre-treated low-density polyethylene (LDPE). The synergistic effect of UV irradiation, heat, and acid pre-treatments on the biodegradability of the polymer was thoroughly assessed. Oxidative structural modifications such as the appearance of carboxylate and carbonyl groups in LDPE chains were recorded post the UV and heat treatments. Furthermore, the nitric acid treatment incorporated NO2 groups into the polymer matrix. Alterations in the polymer thermal stabilities and surface morphologies after each pre-treatment were analyzed using thermogravimetric analysis and scanning electron microscopy (SEM), respectively. The gravimetric analysis revealed a reduction in the weight of the pre-treated LDPE films by 9.21 ± 0.84% after 1 month of the incubation period with Thermomyces lanuginosus. An increase in the thermal stability, disappearance of the incorporated hydrophilic functional groups, and reduction in the carbon content of the polymer samples post the incubation period further justified the biodegradation process. SEM analysis showed modifications in the morphology and texture patterns in pre-treated LDPE after inoculation with Thermomyces lanuginosus. The findings suggest that Thermomyces lanuginosus could be efficient for the decomposition of pre-treated LDPE under laboratory conditions.


Assuntos
Monitoramento Ambiental , Polietileno , Biodegradação Ambiental , Eurotiales , Raios Ultravioleta
7.
Arch Microbiol ; 203(5): 2183-2191, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33620524

RESUMO

The present study approaches the capability of Cephalosporium strain NCIM 1251 to degrade pre-treated polystyrene films. Polystyrene was initially treated with UV for the introduction of oxygen molecules in pure polystyrene samples. UV treatment inserts aliphatic ketones functional group in polystyrene whereas it created C-C stretching after chemical treatment in UV-treated polystyrene as analyzed by Fourier-transform infrared spectroscopy (FTIR). The gravimetric study confirmed a decline in the weight of the pre-treated polystyrene by 20.62 ± 1.47% after 8 weeks of the incubation period. pH, total dissolved solids (TDS), and conductivity of mineral salt media were correlated with the extent of biodegradation. Treatment with UV and acid increased the thermal stability of pure polystyrene, whereas thermal stability decreased in pre-treated polystyrene after incubation with Cephalosporium strain NCIM 1251 as studied by Thermogravimetric analysis (TGA). Scanning Electron Microscopy (SEM) analysis observed revisions in the morphology and surface patterns in pre-treated polystyrene after inoculation with Cephalosporium strain NCIM 1251. The observed findings suggest that the Cephalosporium strain NCIM 1251 could be efficient for the decomposition of pre-treated polystyrene.


Assuntos
Acremonium/metabolismo , Biodegradação Ambiental , Poliestirenos/metabolismo , Raios Ultravioleta , Cetonas/química , Microscopia Eletrônica de Varredura , Poliestirenos/química , Espectroscopia de Infravermelho com Transformada de Fourier
8.
Front Physiol ; 12: 817181, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35002783

RESUMO

In the evolving landscape of highly multiplexed imaging techniques that can be applied to study complex cellular microenvironments, this review characterizes the use of imaging mass cytometry (IMC) to study the human kidney. We provide technical details for antibody validation, cell segmentation, and data analysis specifically tailored to human kidney samples, and elaborate on phenotyping of kidney cell types and novel insights that IMC can provide regarding pathophysiological processes in the injured or diseased kidney. This review will provide the reader with the necessary background to understand both the power and the limitations of IMC and thus support better perception of how IMC analysis can improve our understanding of human disease pathogenesis and can be integrated with other technologies such as single cell sequencing and proteomics to provide spatial context to cellular data.

9.
Otolaryngol Head Neck Surg ; 163(6): 1153-1155, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32662746

RESUMO

Aerosol-generating procedures in the office represent a major concern for health care-associated infection of patients and health care providers by SARS-CoV-2, the causative agent for coronavirus disease 2019 (COVID-19). Although the Centers for Disease Control and Prevention has not yet provided any recommendations for the use of portable air purifiers, air purifiers with high-efficiency particulate air (HEPA) filters have been discussed as an adjunctive means for decontamination of SARS-CoV-2 aerosols in health care settings. This commentary discusses HEPA filter mechanisms of action, decontamination time based on efficiency and flow rate, theoretical application to SARS-CoV-2, and limitations. HEPA filter functionality and prior guidance from the Centers for Disease Control and Prevention for SARS-CoV-1 suggest theoretical efficacy for HEPA filters to decontaminate airborne SARS-CoV-2, although direct studies for SARS-CoV-2 have not been performed. Any portable HEPA purifier utilization for SARS-CoV-2 should be considered an adjunctive infection control measure and undertaken with knowledge of HEPA filter functionality and limitations in mind.


Assuntos
Filtros de Ar , COVID-19/prevenção & controle , Transmissão de Doença Infecciosa/prevenção & controle , Controle de Infecções/instrumentação , SARS-CoV-2 , COVID-19/transmissão , Desenho de Equipamento , Humanos , Controle de Infecções/métodos , Pandemias , Material Particulado
10.
Oncogene ; 39(6): 1231-1245, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31616061

RESUMO

Arginine vasopressin (AVP) and its type-2 receptor (V2R) play an essential role in the regulation of salt and water homeostasis by the kidneys. V2R activation also stimulates proliferation of renal cell carcinoma (RCC) cell lines in vitro. The current studies investigated V2R expression and activity in human RCC tumors, and its role in RCC tumor growth. Examination of the cancer genome atlas (TCGA) database, and analysis of human RCC tumor tissue microarrays, cDNA arrays and tumor biopsy samples demonstrated V2R expression and activity in clear cell RCC (ccRCC). In vitro, V2R antagonists OPC31260 and Tolvaptan, or V2R gene silencing reduced wound closure and cell viability of 786-O and Caki-1 human ccRCC cell lines. Similarly in mouse xenograft models, Tolvaptan and OPC31260 decreased RCC tumor growth by reducing cell proliferation and angiogenesis, while increasing apoptosis. In contrast, the V2R agonist dDAVP significantly increased tumor growth. High intracellular cAMP levels and ERK1/2 activation were observed in human ccRCC tumors. In mouse tumors and Caki-1 cells, V2R agonists reduced cAMP and ERK1/2 activation, while dDAVP treatment had the reverse effect. V2R gene silencing in Caki-1 cells also reduced cAMP and ERK1/2 activation. These results provide novel evidence for a pathogenic role of V2R signaling in ccRCC, and suggest that inhibitors of the AVP-V2R pathway, including the FDA-approved drug Tolvaptan, could be utilized as novel ccRCC therapeutics.


Assuntos
Carcinoma de Células Renais/tratamento farmacológico , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Neoplasias Renais/tratamento farmacológico , Receptores de Vasopressinas/química , Tolvaptan/farmacologia , Animais , Antagonistas dos Receptores de Hormônios Antidiuréticos/farmacologia , Apoptose , Biomarcadores Tumorais , Carcinoma de Células Renais/metabolismo , Carcinoma de Células Renais/patologia , Estudos de Casos e Controles , Ciclo Celular , Proliferação de Células , Feminino , Humanos , Neoplasias Renais/metabolismo , Neoplasias Renais/patologia , Camundongos , Camundongos Nus , Prognóstico , Receptores de Vasopressinas/metabolismo , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
11.
Indian J Palliat Care ; 25(3): 471-473, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31413467

RESUMO

Radiation-induced hemorrhagic cystitis (HC) is an unpleasant and sometimes life-threatening complication confronted while treating pelvic malignancies. A wide array of treatment modalities such as bladder irrigation, fulguration, hyperbaric oxygen therapy, and surgical methods has been proposed to treat hematuria, but there is no consensus on the optimal therapeutic strategy for the same. Reported here is a successful superselective embolization of the bilateral vesical arteries in a patient with refractory radiation-induced HC. This technique proved to be effective in controlling intractable hemorrhage and can be considered an option for the treatment of HC not amenable to conventional techniques.

12.
Int J Hypertens ; 2019: 2087064, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30915238

RESUMO

Heart rate (HR) is strongly associated with both peripheral and central blood pressures. This association has implications in hypertension (HTN) prognosis and management. Elevated HR in HTN further elevates the risk of adverse outcomes. Evidence suggests that HR is an independent risk factor for cardiovascular (CV) and total mortality in patients with HTN. With objective to engage physicians and researchers in India to identify and discuss the implications related to HR management in HTN, experts in the HTN management provided consensus recommendations. The key expert recommendations included the following. (i) Heart rate (HR) has inverse relationship with the central aortic pressure, whereby reduction in HR is associated with an increase in central aortic pressure. This counter-balances the benefit of HR reduction with the harmful effects of rising central aortic pressure. (ii) Increase in the resting HR is associated with increased risk of incident HTN. A linear association between the two is observed especially in individuals with HR >80 bpm. (iii) A reduced HR variability further adds to the propensity for the development of HTN, especially in men. (iv) Each 10 beats per minute increase in the resting HR can substantially increase the risk of adverse CV and mortality outcomes. On treatment HR provides a better prognostic guide. (v) Ambulatory HR with day-time and night-time HR evaluation may also suggest different impact on outcomes. (vi) Target HR in patients with HTN remains unclear. Generally, HR<70 bpm on beta blocker (BB) treatment is advised which may be further lowered in patients with comorbidities like heart failure and coronary artery disease. (vii) Adopting healthy lifestyle approaches to keep check on BP and HR is essential. (viii) Use selective beta-1 blocker in symptomatic cases with elevated HR beyond 80-85 mmHg. BBs are expected to benefit by lowering HR by nearly 10 bpm. Preference should be given to newer beta-blockers which reduce HR and both peripheral and central blood pressure to derive comprehensive advantage of this dual action. (ix) It still remains unclear whether reducing HR in HTN without comorbidities alters the CV and mortality outcomes.

13.
J Agric Food Chem ; 67(9): 2467-2475, 2019 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-30741542

RESUMO

The structure and in vitro antiproliferative activity of anthocyanins in the root tubers of a sweet potato variety cv. Bhu Krishna and the purple leaves of a promising accession S-1467 were studied with the objectives of understanding the structure-activity relationship and comparing the leaf and tuber anthocyanins. The chemical structure of anthocyanins was determined by high-resolution electrospray ionization mass spectrometry analysis. A fluorescence-resonance-energy-transfer-based caspase sensor probe had been used to study the antiproliferative property, and analysis of the cell cycle was performed after staining with propidium iodide and subsequent fluorescence-activated cell sorting. Structurally, the anthocyanins in root tubers were identical to those in leaves, but there was a difference in the proportion of various aglycones present in both. This has led to distinguishable differences in the antiproliferative activity of leaf and tuber anthocyanins to various cancer cells. All nine anthocyanins were found in acylated forms in both tubers and leaves. However, peonidin derivatives were major anthocyanins in tubers (33.98 ± 1.41 mg) as well as leaves (27.68 ± 1.07 mg). The cyanidin derivatives were comparatively higher in leaves (20.55 ± 0.91 mg) than tubers (9.44 ± 0.94 mg). The tuber and leaf anthocyanins exhibited potential antiproliferative properties to MCF-7, HCT-116, and HeLa cancer cells, and the structure of anthocyanins had a critical role in it. The leaf anthocyanins exhibited significantly higher activity against colon and cervical cancer cells, whereas tuber anthocyanins had a slightly greater effect against breast cancer cells.


Assuntos
Antocianinas/química , Antocianinas/farmacologia , Antineoplásicos Fitogênicos/farmacologia , Ipomoea batatas/química , Folhas de Planta/química , Tubérculos/química , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Células HCT116 , Células HeLa , Humanos , Células MCF-7 , Estrutura Molecular , Extratos Vegetais/química , Solventes , Espectrometria de Massas por Ionização por Electrospray
14.
J Appl Microbiol ; 126(4): 1011-1022, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30276940

RESUMO

Biocides (antiseptics and disinfectants) are widely used in hospitals and pharmaceutical industries for contamination control. The emergence of reduced susceptibility to biocides is the major concern and this is caused by various factors, among which plasmid-mediated resistance is common. Many publications describe the antibiotic resistance and mechanisms in a clinical setting. However, there are only limited studies available worldwide addressing the molecular mechanisms of biocide resistance in the pharmaceutical sector. In addition, there is a considerable lack of scientific reports regarding minimum inhibitory concentration (MIC) values of typical biocides against pharmaceutical cleanroom environmental isolates. This review analyses the plasmid-mediated resistance in typical pharmaceutical micro-organisms and prevalence of biocide-resistant genes among common clinical and pharmaceutical isolates. This review discusses the MIC values of biocides in pharmaceutical environmental isolates, indicating the importance of the correlation between the presence or absence of biocide-resistant genes and reduced susceptibility of MIC values. This review recommends that pharmaceutical organizations adopt policies and test methodologies to examine the MICs of common cleanroom biocides against the most common types of cleanroom environmental isolates.


Assuntos
Desinfetantes/farmacologia , Resistência Microbiana a Medicamentos/genética , Microbiologia Ambiental , Preparações Farmacêuticas , Plasmídeos/genética , Anti-Infecciosos Locais/efeitos adversos , Anti-Infecciosos Locais/farmacologia , Humanos , Testes de Sensibilidade Microbiana/normas , Preparações Farmacêuticas/normas , Guias de Prática Clínica como Assunto
15.
J Am Soc Nephrol ; 29(10): 2471-2481, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30209078

RESUMO

BACKGROUND: In patients with autosomal dominant polycystic kidney disease (ADPKD), most of whom have a mutation in PKD1 or PKD2, abnormally large numbers of macrophages accumulate around kidney cysts and promote their growth. Research by us and others has suggested that monocyte chemoattractant protein-1 (Mcp1) may be a signal for macrophage-mediated cyst growth. METHODS: To define the role of Mcp1 and macrophages in promoting cyst growth, we used mice with inducible knockout of Pkd1 alone (single knockout) or knockout of both Pkd1 and Mcp1 (double knockout) in the murine renal tubule. Levels of Mcp1 RNA expression were measured in single-knockout mice and controls. RESULTS: In single-knockout mice, upregulation of Mcp1 precedes macrophage infiltration. Macrophages accumulating around nascent cysts (0-2 weeks after induction) are initially proinflammatory and induce tubular cell injury with morphologic flattening, oxidative DNA damage, and proliferation-independent cystic dilation. At 2-6 weeks after induction, macrophages switch to an alternative activation phenotype and promote further cyst growth because of an additional three-fold increase in tubular cell proliferative rates. In double-knockout mice, there is a marked reduction in Mcp1 expression and macrophage numbers, resulting in less initial tubular cell injury, slower cyst growth, and improved renal function. Treatment of single-knockout mice with an inhibitor to the Mcp1 receptor Ccr2 partially reproduced the morphologic and functional improvement seen with Mcp1 knockout. CONCLUSIONS: Mcp1 is upregulated after knockout of Pkd1 and promotes macrophage accumulation and cyst growth via both proliferation-independent and proliferation-dependent mechanisms in this orthologous mouse model of ADPKD.


Assuntos
Quimiocina CCL2/genética , Quimiocina CCL2/fisiologia , Macrófagos/fisiologia , Rim Policístico Autossômico Dominante/genética , Rim Policístico Autossômico Dominante/patologia , Animais , Quimiocina CCL2/deficiência , Dano ao DNA , Modelos Animais de Doenças , Humanos , Túbulos Renais/patologia , Túbulos Renais/fisiopatologia , Ativação de Macrófagos/efeitos dos fármacos , Ativação de Macrófagos/genética , Ativação de Macrófagos/fisiologia , Macrófagos/efeitos dos fármacos , Macrófagos/patologia , Masculino , Camundongos , Camundongos Knockout , Rim Policístico Autossômico Dominante/fisiopatologia , Pirrolidinas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Receptores CCR2/antagonistas & inibidores , Canais de Cátion TRPP/deficiência , Canais de Cátion TRPP/genética , Regulação para Cima
16.
Spectrochim Acta A Mol Biomol Spectrosc ; 204: 537-547, 2018 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-29975916

RESUMO

In the present work, the structural and optical properties of borotellurite glasses co-doped with Dy3+ ions and Ag nanoparticles were investigated. From HR-TEM analysis, the average Ag nanoparticle diameter was calculated as 13.7 ±â€¯1 nm. The negative sign of the bonding parameter explored the ionic nature of metal-ligand (DyO) bonds. The emission spectra exhibited three emission bands in blue, yellow and red regions corresponding to 4F9/2 → 6H15/2, 4F9/2 → 6H13/2 and 4F9/2 → 6H11/2 transitions, respectively. The Yellow/Blue (Y/B) ratio of optimal BTD0.5A glass was found to be 1.881 and this low Y/B ratio indicated the fact that Dy3+ ions were located in higher symmetrical ligand environment. The CCT values are found to vary from 3717 to 3800 K and hence the present glasses may emit cool white light when excited with UV lamp. The radiative parameters were calculated for all the emission transitions by using JO theory. The decay curves are found to show non-exponential behavior for all the studied glasses. The obtained results were discussed in detail and compared with similar reported glasses.

17.
RSC Adv ; 8(41): 23323-23331, 2018 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-35540142

RESUMO

Eu3+-activated Ba2Y5B5O17 (Ba2Y5-x Eu x B5O17; x = 0.1-1) red-emitting phosphors were synthesized by the conventional high temperature solid-state reaction method in an air atmosphere. Powder X-ray diffraction (XRD) analysis confirmed the pure phase formation of the as-synthesized phosphors. Morphological studies were performed using field emission-scanning electron microscopy (FE-SEM). The photoluminescence spectra, lifetimes, color coordinates and internal quantum efficiency (IQE) as well as the temperature-dependent emission spectra were investigated systematically. Upon 396 nm excitation, Ba2Y5-x Eu x B5O17 showed red emission peaking at 616 nm which was attributed to the 5D0 → 7F2 electric dipole transition of Eu3+ ions. Meanwhile, the influences of different concentrations of Eu3+ ions on the PL intensity were also discussed. The optimum concentration of Eu3+ ions in the Ba2Y5-x Eu x B5O17 phosphors was found to be x = 0.8. The concentration quenching mechanism was attributed to the dipole-dipole interaction and the critical distance (R c) for energy transfer among Eu3+ ions was determined to be 5.64 Å. The asymmetry ratio [(5D0 → 7F2)/(5D0 → 7F1)] of Ba2Y4.2Eu0.8B5O17 phosphors was calculated to be 3.82. The fluorescence decay lifetimes were also determined for Ba2Y5-x Eu x B5O17 phosphors. In addition, the CIE color coordinates of the Ba2Y4.2Eu0.8B5O17 phosphors (x = 0.653, y = 0.345) were found to be very close to the National Television System Committee (NTSC) standard values (x = 0.670, y = 0.330) of red emission and also showed high color purity (∼94.3%). The corresponding internal quantum efficiency of the Ba2Y4.2Eu0.8B5O17 sample was measured to be 47.2%. Furthermore, the as-synthesized phosphors exhibited good thermal stability with an activation energy of 0.282 eV. The above results revealed that the red emitting Ba2Y4.2Eu0.8B5O17 phosphors could be potential candidates for application in near-UV excited white light emitting diodes.

18.
Protein Expr Purif ; 143: 9-13, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29031680

RESUMO

We report the molecular cloning, expression, and single-step homogeneous purification of a full-length asparaginyl tRNA synthetase (NRS) from Fasciola gigantica (FgNRS). Fasciola gigantica is a parasitic liver fluke of the class Trematoda. It causes fascioliasis that infects the liver of various mammals, including humans. Aminoacyl tRNA synthetases (AARS) catalyze the first step of protein synthesis. They attach an amino acid to its cognate tRNA, forming an amino acid-tRNA complex. The gene that codes for FgNRS was generated by amplification by polymerase chain reaction. It was then inserted in the expression vector pQE30 under the transcriptional control of the bacteriophage T5 promoter and lac operator. M15 Escherichia coli strain transformed with the FgNRS expression vector pQE30-NRS accumulates large amounts of a soluble protein of about 61 kDa. The protein was purified to homogeneity using immobilized metal affinity chromatography. The recombinant protein was further confirmed by immunoblotting with anti-His antibody. Following size exclusion chromatography, the FgNRS was stable and observed to be a dimeric protein. In this study, the expression and purification procedures have provided a simple and efficient method to obtain full-length FgNRS in large quantities. This will provide an opportunity to study the structure, dynamics and function of NRS.


Assuntos
Aspartato-tRNA Ligase/metabolismo , Fasciola/enzimologia , Fasciola/genética , Aminoacil-RNA de Transferência/metabolismo , Proteínas Recombinantes/metabolismo , Animais , Aspartato-tRNA Ligase/química , Aspartato-tRNA Ligase/genética , Aspartato-tRNA Ligase/isolamento & purificação , Western Blotting , Cromatografia em Gel , Aminoacil-RNA de Transferência/química , Aminoacil-RNA de Transferência/genética , Aminoacil-RNA de Transferência/isolamento & purificação , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação
19.
RSC Adv ; 8(58): 33403-33413, 2018 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-35548130

RESUMO

The Sm3+ ion singly doped LiCa3ZnV3O12 (LCZV) phosphors were synthesized by a traditional high-temperature solid-state method. The luminescence characteristics of the as-prepared samples were studied by photoluminescence excitation and emission spectra. Under 343 nm excitation, the synthesized phosphors exhibited color controllable emission induced by the efficient energy transfer from VO4 3- groups to Sm3+ ions. Besides, the energy transfer efficiency was revealed to be about 58.4% when the dopant concentration was 4 mol%. By utilizing the as-prepared LCZV:Sm3+ phosphors, commercial BaMgAl10O7:Eu2+ blue-emitting phosphors and a near-ultraviolet light-emitting diode (LED) chip, a white LED device was fabricated. Under an injection current of 100 mA, the packaged LED device emitted pure white light with high color rendering index (88.4) and proper correlated color temperature (4320 K). By analyzing the thermal quenching behavior of the VO4 3- groups and Sm3+ ions, the optical thermometric behavior of the Sm3+-doped LCZV compounds was investigated. The maximum absolute sensor sensitivity and relative sensor sensitivity were found to be 0.25 K-1 and 1.8% K-1, respectively. Additionally, the emitting color of the studied samples was dependent on the temperature. Ultimately, the Sm3+-doped LCZV phosphors were potential candidates for indoor illumination, optical thermometry and safety signals in high temperature environments.

20.
Dis Aquat Organ ; 125(2): 115-124, 2017 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-28737157

RESUMO

We report the spontaneous occurrence of oral neoplasms in pickhandle barracuda Sphyraena jello Cuvier, 1829 from Parangipettai, on the southeast coast of India. A total of 11736 fish were examined, of which 43 were affected with oral tumours, with an overall prevalence of 0.37%. Gross and clinical symptoms included reddish to grayish-white distended tumourous growths on the gingiva, intra-oral bones and tongue. The tumours exhibited delayed eruption and intra- or extra-oral swelling, varied in consistency from extremely firm to fleshy and released mucinous material. The majority of tumours consisted of numerous clumped toothlets, but some included hardened tissues. Local area invasion/transmission was observed in most cases; however, necropsy examination revealed no gross evidence of distant metastasis into visceral organs. Radiographic examination of compound odontomas revealed distinct unilocular radio-opaque mini-toothlets surrounded by defined radiolucency, whereas complex odontomas exhibited unilocular and indistinct radio-opaque masses within a much more extensive radiolucent zone. Histopathologically, the intra-oral tumour lesions were characterized by numerous imperfect (germ) toothlets consisting of a disorganized combination of dental tissues: pulp tissues with manifested and predominantly mixed hard dental tissues of immature dentine and enamel, numerous small to large and round to polyhedral ossicles embedded in hypocellular fibrous stromal tissues and sparsely spaced bland spindloid cells with cleft-like spaces of loose mucoid stroma. Histochemically, the neoplastic lesions stained positive for periodic acid-Schiff and Masson's trichrome. Based on the clinical and histological findings, the tumours were diagnosed as compound odontomas, complex odontomas, odontogenic myxomas, lingual myxomas and psammomatoid ossifying fibromas.


Assuntos
Doenças dos Peixes/patologia , Neoplasias Bucais/veterinária , Animais , Doenças dos Peixes/epidemiologia , Peixes , Índia/epidemiologia , Neoplasias Bucais/epidemiologia , Neoplasias Bucais/patologia
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