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1.
Nanoscale Adv ; 5(22): 6102-6114, 2023 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-37941953

RESUMO

This study examines the numerical representation of fluid flow on the Maxwell model in a double-diffusive boundary layer over a horizontal plate. The investigation incorporates slip conditions, encompassing momentum slip, thermal slip, and suction parameters. Moreover, the study includes the inspiration of thermal radiation, heat generation, and mass transfer. The governing partial differential equations (pertaining to momentum, continuity, energy transport, and mass transport) are transformed into ordinary differential equations (ODEs) using appropriate similarity transformations. To solve these equations in conjunction with suitable boundary conditions, the bvp4c inbuilt software is implemented. This is achieved through the shooting approach employed in MATLAB. A comprehensive agreement between the numerical technique and previously published findings demonstrates its efficacy. The outcomes are presented through graphical representations and tables, showcasing various parameters such as momentum slip, temperature slip, local Nusselt number, Sherwood number, and suction parameter. The primary motivation of this research lies in investigating the behaviour of Maxwell fluid flow in the absence of slip conditions. The study of Maxwell fluid flow over a flat plate with the combined effects of suction, thermal slip, and momentum slip conditions has a wide range of practical applications that span multiple industries, contributing to improved designs, efficiency, and understanding of fluid behaviour in various systems. The main aim of this study is to present streamlined results under varying conditions, explicitly investigating the influence of suction effects and slip conditions on the flow.

2.
Chemosphere ; 303(Pt 1): 134956, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35588873

RESUMO

Oil spillage is one of the most common pollutants which brings greater economic loss and damage to the environment. The intensity and amount of the damage may vary depending on factors such as the type of oil, the location of the spill, and the climatic parameters in the area. As for any pollution management, the guidelines are Reduce, Re-use, Recover and Disposal. Amongst the other remediation processes, Bioremediation is amongst the most significant environmentally friendly and cost-effective approaches for marine biological restoration because it allows complex petroleum hydrocarbons in spilt oil to decompose completely into harmless compounds. Mainly, the necessity and essence of bioremediation were talked about. This review discussed the bacteria identified which are capable of degrading various oil related pollutants and their components. Also, it covered the various media components used for screening and growing the oil degrading bacteria and the pathways that are associated with oil degradation. This article also reviewed the recent research carried out related to the oil degrading bacteria.


Assuntos
Poluentes Ambientais , Poluição por Petróleo , Petróleo , Bactérias/metabolismo , Biodegradação Ambiental , Poluentes Ambientais/metabolismo , Hidrocarbonetos/metabolismo , Petróleo/metabolismo
3.
Bioresour Technol ; 346: 126442, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34848334

RESUMO

The present study proposes a system for co-composting food waste and poultry manure amended with rice husk biochar at different doses (0, 3, 5, 10%, w/w), saw dust, and salts. The effect of rice husk biochar on the characteristics of final compost was evaluated through stabilization indices such as electrical conductivity, bulk density, total porosity, gaseous emissions and nitrogen conservation. Results indicated that when compared to control, the biochar amendment extended the thermophilic stage of the composting, accelerated the biodegradation and mineralization of substrate mixture and helped in the maturation of the end product. Carbon dioxide, methane and ammonia emissions were reduced and the nitrogen conservation was achieved at a greater level in the 10% (w/w) biochar amended treatments. This study implies that the biochar and salts addition for co-composting food waste and poultry manure is beneficial to enhance the property of the compost.


Assuntos
Compostagem , Eliminação de Resíduos , Animais , Carvão Vegetal , Poeira , Esterco , Minerais , Nitrogênio/análise , Aves Domésticas , Sais , Solo
4.
Bioprocess Biosyst Eng ; 42(6): 1053-1064, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30879146

RESUMO

Bacillus pumilus, the thermophilic microorganism, was used to biosynthesise lipase of specific activity 5173 U. The purified lipase was highly stable in the pH range from 1 to 7 and temperature at 50 °C. The functionalized nanoporous activated carbon matrix was used for the immobilization of lipase at the optimum conditions and was used for the hydrolysis of palm oil-containing wastewater at optimum time, 3 h, pH 7, and at temperature 50 °C. The hydrolyzed palm oil wastewater was treated in an upflow anaerobic reactor for the removal of soluble COD at hydraulic retention time (HRT) of 3 days. The anaerobic-treated wastewater was applied to the fluidized immobilized carbon catalytic oxidation (FICCO) reactor at HRT of 16 h to reduce the soluble COD. The FICCO-treated wastewater was further treated in chemo-autotrophic activated carbon oxidation (CAACO) reactor to reduce the COD less than 100 mg/L.


Assuntos
Bacillus pumilus/enzimologia , Proteínas de Bactérias/química , Reatores Biológicos , Enzimas Imobilizadas/química , Lipase/química , Óleo de Palmeira/química , Esgotos , Catálise , Temperatura Alta , Concentração de Íons de Hidrogênio , Oxirredução
5.
Colloids Surf B Biointerfaces ; 65(2): 292-9, 2008 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-18565742

RESUMO

A new carrier matrix for nanoemulsion drug delivery was synthesized from glycine as the raw material, using mesoporous/microporous electron rich carbon-silica composite surface (MAC(800)). MAC(800) was prepared from rice husk in two-stage carbonization. The surface area, pore volume, and pore size distribution of MAC(800) were measured, using nitrogen adsorption isotherms at 77K. The unpaired electron density of MAC(800) was measured in electron spin resonance spectroscopy (ESR), using TEMPOL (4-hydroxy-2,2,6,6-tetramethyl piperidine-1-oxyl) as the reference spin probe. Glycine was converted into ketene at the surface of MAC(800), which further underwent radical polymerization to form a low molecular weight ketene polymer (LMKP) of ester structure. The structure and the properties of LMKP were confirmed through (13)C, (1)H and DEPT nuclear magnetic resonance (NMR) spectroscopy, attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and size exclusion chromatography (SEC). The two hydrophilic drugs namely ciprofloxacin hydrochloride (CPH) and gentamicin sulphate (GS) were chosen for the nanoemulsion preparation and characterization. They were characterized for morphology, interaction of drugs with the polymer and their crystallinity, using HR-TEM, DSC and XRD, respectively. The encapsulation efficiency of the LMKP towards the drugs ciprofloxacin hydrochloride and gentamicin sulphate were 26% and 12%, respectively. The dissolution studies of the nanoemulsion were carried out for the pH 6.5, 7.4 and 8.0. The cytocompatibility studies were done for LMKP as well as nanoemulsion using Hep2 epithelial cells.


Assuntos
Carbono/química , Emulsões , Etilenos/química , Cetonas/química , Nanotecnologia , Poliésteres/química , Dióxido de Silício/química , Varredura Diferencial de Calorimetria , Espectroscopia de Ressonância de Spin Eletrônica , Microscopia Eletrônica de Transmissão , Peso Molecular , Solubilidade
6.
J Mater Sci Mater Med ; 19(9): 3005-14, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18389347

RESUMO

A ketene based Low molecular weight polymer (LMKP) having ester functional group was prepared using glycine through surface initiated anionic polymerization. NMR, ATR-FTIR & SEC were used to characterize the LMKP. The LMKP and acrylamide (AAm) were co-polymerised in methyl ethyl ketone to yield semi-IPN nanohydrogels (NHG). Benzoyl peroxide (BPO) was used as an initiator and N,N-methylene bisacrylamide (MBA) as crosslinking agent. Formation of NHG was confirmed through frequency shift in LMKP and poly acrylamide (PAAm) in FTIR spectroscopy. Photon correlation spectroscopy reveals that the sizes of the NHG were in the range of 140-225 nm and Transmission Electron Micrograph (TEM) also confirms the nano dimension of NHG. Biocompatibility of the NHG was confirmed through the cytotoxicity analysis. The swelling and diffusion behaviour of NHG, prepared under various formulations, were evaluated. The swelling pattern of NHG was studied at different pH conditions. The drug delivery capacity of NHG was investigated using ciprofloxacin as a model drug. The drug release kinetics of NHG suggested their anomalous (non-fickian) behaviour.


Assuntos
Resinas Acrílicas/química , Etilenos/química , Hidrogéis/química , Cetonas/química , Nanotecnologia/métodos , Poliésteres/química , Materiais Biocompatíveis , Química Farmacêutica/métodos , Ciprofloxacina/farmacocinética , Sistemas de Liberação de Medicamentos , Íons , Nanopartículas/química , Fótons , Polímeros/química , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície
7.
Chemosphere ; 69(2): 262-70, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17544053

RESUMO

Investigations were carried out in batch modes for studying the immobilization behavior of polyphenol oxidase (PPO) on two different mesoporous activated carbon matrices, MAC400 and MAC200. The PPO was immobilized onto MAC400 and MAC200 at various enzyme activities 5 x 10(4), 10 x 10(4), 20 x 10(4), 30 x 10(4)Ul(-1), at pH 5-8, and at temperature ranging from 10 to 40 degrees C. The intensity of immobilization of PPO increased with increase in temperature and initial activities, while it decreased with increase in pH. Immobilization onto MAC400 followed the Langmuir model while Langmuir and Freundlich models could fit MAC200 data. Non-linear pseudo first order, pseudo second order and intraparticle diffusion models were evaluated to understand the mechanism of immobilization. The free and immobilized enzyme kinetic parameters (K(m) and V(max)) were determined by Michaelis-Menten enzyme kinetics. The K(m) values for free enzyme, PPO immobilized in MAC400 and in MAC200 were 0.49, 0.41 and 0.65 mM, respectively. The immobilization of PPO in carbon matrices was confirmed using FT-IR spectroscopy and scanning electron microscopy.


Assuntos
Carbono/metabolismo , Catecol Oxidase/metabolismo , Enzimas Imobilizadas/metabolismo , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier , Termodinâmica
8.
J Biosci ; 30(3): 359-70, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16052074

RESUMO

Real time kinetic studies were used to map conformational epitopes in human chorionic gonadotropin (hCG) for two monoclonal antibodies (MAbs). The epitopes were identified in the regions (alpha 5--14 and alpha 55--62). The association rate constant (k+1) was found to be altered by chemical modification of hCG, and the ionic strength of the reaction medium. Based on these changes, we propose the presence of additional interactions away from the epitope- paratope region in the hCG-MAb reaction. We have identified such incidental interacting regions (IIRs) in hCG to be the loop region alpha 35--47 and alpha 60--84. The IIRs contribute significantly towards the KA of the interaction. Therefore, in a macromolecular interaction of hCG and its MAb, KA is determined not only by epitopeparatope interaction but also by the interaction of the nonepitopic-nonparatopic IIRs. However, the specificity of the interaction resides exclusively with the epitope-paratope pair.


Assuntos
Anticorpos Monoclonais , Gonadotropina Coriônica/química , Mapeamento de Epitopos/métodos , Epitopos/química , Afinidade de Anticorpos , Sítios de Ligação de Anticorpos , Gonadotropina Coriônica/imunologia , Dissulfetos , Humanos , Cinética , Modelos Moleculares , Ligação Proteica , Conformação Proteica
9.
Malays J Pathol ; 27(2): 75-81, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17191389

RESUMO

Antimicrobial resistance to the extended-spectrum cephalosporins is increasingly reported worldwide. In the local setting, nosocomial infections with multi-resistant Gram-negative bacilli are not uncommon and are a growing concern. However, there is limited data on the carriage rates of such organisms in the local setting. In May 2001, a prospective study was carried out to determine the enteric carriage rates of ceftazidime-resistant Gram negative bacilli (CAZ-R GNB) among residents of nursing homes and from in-patients of the geriatric and adult haematology wards of University Malaya Medical Centre. Ceftazidime-resistant Gram-negative bacilli (CAZ-R GNB) were detected in 25 samples (30%), out of which 6 were from nursing home residents, 5 from geriatric in-patients and 14 from the haematology unit. A total of 28 CAZ-R GNB were isolated and Escherichia coli (10) and Klebsiella pneumoniae (7) were the predominant organisms. Resistance to ceftazidime in E. coli and Klebsiella was mediated by extended-spectrum beta-lactamases (ESBLs). Although the majority of the CAZ-R GNB were from patients in the haematology ward, the six nursing home residents with CAZ-R GNB were enteric carriers of ESBL-producing coliforms. Prior exposure to antibiotics was associated with carriage of ESBL organisms and to a lesser extent, the presence of urinary catheters.


Assuntos
Infecções por Enterobacteriaceae/epidemiologia , Enterobacteriaceae/isolamento & purificação , Fezes/microbiologia , beta-Lactamases/metabolismo , Idoso , Antibacterianos/uso terapêutico , Ceftazidima/uso terapêutico , Resistência a Medicamentos , Enterobacteriaceae/enzimologia , Infecções por Enterobacteriaceae/complicações , Doenças Hematológicas/complicações , Doenças Hematológicas/microbiologia , Humanos , Pacientes Internados/estatística & dados numéricos , Casas de Saúde/estatística & dados numéricos , Reação em Cadeia da Polimerase , Polimorfismo Conformacional de Fita Simples , Prevalência , Resistência beta-Lactâmica
10.
Biochim Biophys Acta ; 1572(1): 31-6, 2002 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-12204330

RESUMO

A thermodynamic analysis of the interaction of 125I-labeled human chorionic gonadotropin (IhCG) with two of its monoclonal antibodies (MAbs) was carried out. The dissociation profile of IhCG-MAb complex conforms to a two-step model. vant Hoff enthalpies were calculated with the K(A) (equilibrium constant) values obtained from dissociation at different temperatures. Free energy and entropy changes were calculated using the standard equations. DeltaH values for one of the MAbs, viz. VM7 were favorable at temperatures beyond 30 degrees C. Interestingly, the DeltaS values were also favorable at all temperatures. In the case of MAb VM4a, however, the interaction throughout the temperature range was driven by large favorable entropic contributions, indicating the importance of hydrophobic interaction in the binding of this MAb to hCG. The energetics of the interaction of these two monoclonals with hCG is discussed.


Assuntos
Anticorpos Monoclonais/química , Reações Antígeno-Anticorpo , Gonadotropina Coriônica/química , Termodinâmica , Gonadotropina Coriônica/imunologia , Radioisótopos do Iodo , Cinética , Temperatura
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