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1.
Biodegradation ; 35(1): 1-46, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37436665

RESUMO

Petroleum hydrocarbon (PH) pollution has mostly been caused by oil exploration, extraction, and transportation activities in colder regions, particularly in the Arctic and Antarctic regions, where it serves as a primary source of energy. Due to the resilience feature of nature, such polluted environments become the realized ecological niches for a wide community of psychrophilic hydrocarbonoclastic bacteria (PHcB). In contrast, to other psychrophilic species, PHcB is extremely cold-adapted and has unique characteristics that allow them to thrive in greater parts of the cold environment burdened with PHs. The stated group of bacteria in its ecological niche aids in the breakdown of litter, turnover of nutrients, cycling of carbon and nutrients, and bioremediation. Although such bacteria are the pioneers of harsh colder environments, their growth and distribution remain under the influence of various biotic and abiotic factors of the environment. The review discusses the prevalence of PHcB community in colder habitats, the metabolic processes involved in the biodegradation of PH, and the influence of biotic and abiotic stress factors. The existing understanding of the PH metabolism by PHcB offers confirmation of excellent enzymatic proficiency with high cold stability. The discovery of more flexible PH degrading strategies used by PHcB in colder environments could have a significant beneficial outcome on existing bioremediation technologies. Still, PHcB is least explored for other industrial and biotechnological applications as compared to non-PHcB psychrophiles. The present review highlights the pros and cons of the existing bioremediation technologies as well as the potential of different bioaugmentation processes for the effective removal of PH from the contaminated cold environment. Such research will not only serve to investigate the effects of pollution on the basic functional relationships that form the cold ecosystem but also to assess the efficacy of various remediation solutions for diverse settings and climatic conditions.


Assuntos
Ecossistema , Petróleo , Hidrocarbonetos/metabolismo , Biodegradação Ambiental , Bactérias/metabolismo
2.
J Basic Microbiol ; 60(3): 198-206, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31856349

RESUMO

The growth of technology and requirements globally for various commodities has brought about new challenges. Biofilms are aggregations of microbial cells, which contaminate and spoil industrial components and environments. These microbial cells with extracellular polymeric substances colonize living and nonliving surfaces and pose a serious problem for all industries, affecting their processes, leading to a reduction of product quality and economic loss. Industries, such as medical, food, water, dairy, wine, marine, power plants are exposed to biofilm formation. Pipe blockages, waterlogging and reduction of the heat-transfer efficiency, hamper the operating system of plants. Many industries do not set up remedial measures to control biofilm formation as they are not aware of this threat. Various conventional methods to control these biofilms are adopted by industries in their regular workflow, but these are temporary solutions. This calls for further research into remediation of the biofilm and its control for industrial components. This review article addresses the problems of biofilms and proposes solutions for various industrial components. Nanotechnology promises several options, and bring about a new aspect into the industrial economy, by solving the problems of environmental biofilms.


Assuntos
Biofilmes , Incrustação Biológica/prevenção & controle , Microbiologia Ambiental , Indústrias , Biofilmes/crescimento & desenvolvimento , Indústrias/economia , Nanotecnologia
3.
Bull Environ Contam Toxicol ; 104(5): 619-626, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32172338

RESUMO

Cadmium contamination of agricultural soils is a serious problem due to its toxic effects on health and yield of crop plants. This study investigates the potential of low-dose nano-TiO2 as soil nanoremediation on Cd toxicity in cowpea plants. To achieve this goal, cowpea seeds were germinated on Cd-spiked soils at 10 mg/kg for 14 days and later augmented with 100 mg nTiO2/kg (nTiO2-50 nm and bTiO2-68 nm, respectively). The results showed that chlorophylls were not altered by nano-TiO2 intervention. Cadmium partitioning in roots and leaves was reduced by the applied nano-TiO2 but significantly higher than control. Ascorbate peroxidase and catalase activities in roots and leaves were promoted by nano-TiO2 intervention compared to control and sole Cd, respectively. However, magnitudes of activity of enzyme activities were higher in nTiO2 compared to bTiO2 treatments. The enhanced enzymes activity led to reduced malonaldehyde content in plant tissues. The study concludes that soil application of nano-TiO2 could be a green alternative to ameliorate soil Cd toxicity in cowpea plants.


Assuntos
Cádmio/metabolismo , Nanopartículas/química , Estresse Oxidativo/efeitos dos fármacos , Poluentes do Solo/toxicidade , Titânio/farmacologia , Vigna/efeitos dos fármacos , Vigna/enzimologia , Antioxidantes/metabolismo , Ascorbato Peroxidases/metabolismo , Cádmio/toxicidade , Clorofila/metabolismo , Germinação , Malondialdeído/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/enzimologia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/enzimologia , Sementes , Solo/química , Poluentes do Solo/metabolismo , Titânio/química , Vigna/crescimento & desenvolvimento
4.
J Cell Biochem ; 119(10): 8574-8587, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30058078

RESUMO

Hepatitis C virus (HCV) nonstructural protein 5B (NS5B) is an RNA-dependent RNA polymerase that plays a key role in HCV replication, and, hence, NS5B is an attractive target for hepatitis C drug discovery. Hepatitis C is a chronic liver disease affecting the global population significantly. Many NS5B inhibitors targeting active site were launched in recent years, however, still there exists a pressing need for cost-effective therapies with pan genotypic activity and therapies targeting niche HCV population with comorbities and resistant to earlier therapies. The objective of the current study is to identify potential anti-HCV agents from FDA approved drugs that are already in the market for a different disease-Drug repurposing approach. A combination of computational chemistry and computational biology techniques was used to discover potential therapies for hepatitis C targeting the NS5B Thumb I allosteric site. Computational chemistry analysis emphasized the fact that fluvastatin, a lipid lowering agent, and olopatadine, an antihistamine, exhibited good binding affinity to NS5B. In addition, gene set enrichment analysis brought to light the significant overlap between disease characteristic features and the mechanism of action of fluvastatin and olopatadine. The current study concludes the potentially beneficial use of fluvastatin in niche hepatitis C patient population suffering from nonalcoholic fatty liver diseases.


Assuntos
Antivirais/química , Biologia Computacional/métodos , Reposicionamento de Medicamentos/métodos , Fluvastatina/química , Hepacivirus/enzimologia , Cloridrato de Olopatadina/química , Proteínas não Estruturais Virais/química , Sítio Alostérico , Antivirais/uso terapêutico , Fluvastatina/metabolismo , Fluvastatina/uso terapêutico , Hepatite C/tratamento farmacológico , Hepatite C/genética , Humanos , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Ligantes , Redes e Vias Metabólicas/genética , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Cloridrato de Olopatadina/metabolismo , Cloridrato de Olopatadina/uso terapêutico , Ligação Proteica , Estrutura Secundária de Proteína , Transcriptoma , Interface Usuário-Computador , Proteínas não Estruturais Virais/antagonistas & inibidores
5.
Ecotoxicol Environ Saf ; 155: 86-93, 2018 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-29510313

RESUMO

Increased use of nanoparticles-based products in agriculture portends important implications for agriculture. Therefore, the impact of nano-copper particles (<25 nm and 60-80 nm) on Cu uptake, bioaccumulation (roots, leaves and seeds), activity of ascorbate peroxidase (APX), catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GR), and lipid peroxidation in leaves and roots of Vigna unguiculata (cowpea) was studied. Plants were exposed to four levels (0, 125, 500 and 1000 mg/kg) of 25 nm or 60-80 nm nano-Cu for 65 days. Results indicated significant (P<.05) uptake of Cu at all nano-Cu levels compared to control, and bioaccumulation increased in seeds by at least 250%. Response of antioxidant enzymes to both nano-Cu types was concentration-dependent. Activity of APX and GR was enhanced in leaves and roots in response to both nano-Cu treatments in similar patterns compared to control. Both nano-Cu increased CAT activity in roots while SOD activity reduced in both leaves and roots. This shows that response of antioxidant enzymes to nano-Cu toxicity was organ-specific in cowpea. Malondialdehyde, a measure of lipid peroxidation, increased at 500 -1000 mg/kg of 25 nm nano-Cu in leaves by average of 8.4%, and 60-80 nm nano-Cu in root by 52.8%, showing particle-size and organ-dependent toxicity of nano-Cu. In conclusion, exposure of cowpea to nano-Cu treatments increased both the uptake and bioaccumulation of Cu, and also promoted the activity of APX and GR in root and leaf tissues of cowpea. Therefore, APX- and GR-activity level could be a useful predictive biomarker of nano-Cu toxicity in cowpea.


Assuntos
Cobre/toxicidade , Nanopartículas Metálicas/toxicidade , Poluentes do Solo/toxicidade , Vigna/efeitos dos fármacos , Ascorbato Peroxidases/metabolismo , Catalase/metabolismo , Glutationa Redutase/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Malondialdeído/farmacologia , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Sementes/efeitos dos fármacos , Sementes/metabolismo , Superóxido Dismutase/metabolismo , Vigna/metabolismo
6.
Int J Biol Macromol ; : 133684, 2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-39084979

RESUMO

For Bacterial Nanocellulose (BNC) production, standard methods are well-established, but there is a pressing need to explore cost-effective alternatives for BNC commercialization. This study investigates the feasibility of using syrup prepared from maize stalk as a valuable nutrient and sustainable carbon source for BNC production. Our study achieved a remarkable BNC production yield of 19.457 g L-1 by utilizing Komagataeibacter saccharivorans NUWB1 in combination with components from the Hestrin-Schramm (HS) medium. Physicochemical properties revealed that the obtained BNC exhibited a crystallinity index of 60.5 %, tensile strength of 43.5 MPa along with enhanced thermostability reaching up to 360 °C. N2 adsorption-desorption isotherm of the BNC displayed characteristics of type IV, indicating the presence of a mesoporous structure. The produced BNC underwent thorough investigation, focusing on its efficacy in addressing environmental concerns, particularly in removing emerging pharmaceutical pollutants like Metformin and Paracetamol. Remarkably, the BNC exhibited strong adsorption capabilities, aligning with the Langmuir isotherm and pseudo-second-order model. Thermodynamic analysis confirmed a spontaneous and endothermic adsorption process. Furthermore, the BNC showed potential for regeneration, enabling up to five recycling cycles. Cytotoxicity and oxidative stress assays validated the biocompatibility of BNC. Lastly, the BNC films displayed an impressive 88.73 % biodegradation within 21 days.

7.
Membranes (Basel) ; 13(8)2023 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-37623797

RESUMO

Membrane biofouling is the consequence of the deposition of microorganisms on polymer membrane surfaces. Polymeric membranes have garnered more attention for filtering and purifying water because of their ease of handling, low cost, effortless surface modification, and mechanical, chemical, and thermal properties. The sizes of the pores in the membranes enable micro- and nanofiltration, ultrafiltration, and reverse osmosis. Commonly used polymers for water filter membranes are polyvinyl chloride (PVA), polyvinylidene fluoride (PVDF), polyamide (PA), polyethylene glycol (PEG), polyethersulfone (PES), polyimide (PI), polyacrylonitrile (PAN), polyvinyl alcohol (PA), poly (methacrylic acid) (PMAA), polyaniline nanoparticles (PANI), poly (arylene ether ketone) (PAEK), polyvinylidene fluoride polysulfone (PSF), poly (ether imide) (PEI), etc. However, these polymer membranes are often susceptible to biofouling because of inorganic, organic, and microbial fouling, which deteriorates the membranes and minimizes their lives, and increases operating costs. Biofouling infection on polymer membranes is responsible for many chronic diseases in humans. This contamination cannot be eliminated by periodic pre- or post-treatment processes using biocides and other chemicals. For this reason, it is imperative to modify polymer membranes by surface treatments to enhance their efficiency and longevity. The main objective of this manuscript is to discuss application-oriented approaches to control biofouling on polymer membranes using various surface treatment methods, including nanomaterials and fouling characterizations utilizing advanced microscopy and spectroscopy techniques.

8.
3 Biotech ; 13(5): 163, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37159590

RESUMO

Nanoengineered nanoparticles have a significant impact on the morphological, physiology, biochemical, cytogenetic, and reproductive yields of agricultural crops. Metal and metal oxide nanoparticles like Ag, Au, Cu, Zn, Ti, Mg, Mn, Fe, Mo, etc. and ZnO, TiO2, CuO, SiO2, MgO, MnO, Fe2O3 or Fe3O4, etc. that found entry into agricultural land, alter the morphological, biochemical and physiological system of crop plants. And the impacts on these parameters vary based on the type of crop and nanoparticles, doses of nanoparticles and its exposure situation or duration, etc. These nanoparticles have application in agriculture as nanofertilizers, nanopesticides, nanoremediator, nanobiosensor, nanoformulation, phytostress-mediator, etc. The challenges of engineered metal and metal oxide nanoparticles pertaining to soil pollution, phytotoxicity, and safety issue for food chains (human and animal safety) need to be understood in detail. This review provides a general overview of the applications of nanoparticles, their potentials and challenges in agriculture for sustainable crop production.

9.
Int J Biol Macromol ; 251: 126309, 2023 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-37573902

RESUMO

In the present study, bacterial nanocellulose/graphene oxide nano-biocomposites (BNC-GO-NBCs) were fabricated by Komagataeibacter saccharivorans NUWB1 using an in-situ method involving three time-dependent approaches. Physicochemical studies showed that the chosen dried BNC-GO-NBC possessed a three-dimensional interconnected porous structure of BNC with GO layers embedded within the BNC fibrils. BNC-GO-NBC had a crystallinity index of 74.21 %, higher thermostability up to 380 °C and could withstand a tensile load of 84.72 MPa. N2 adsorption-desorption isotherm of the BNC-GO-NBC was found to be of type IV, suggesting a mesoporous type structure with a total pore volume and surface area of 6.232e-04 cc g-1 and 10.498 m2. BNC-GO-NBC exhibited remarkable adsorption capacity for two cationic dyes, Rhodamine B (RhB) and Acridine Orange (AO), and the adsorption data conformed well to the Langmuir isotherm (R2 = 0.99) and pseudo-second-order model. Thermodynamic studies indicated that the adsorption process was spontaneous and endothermic. Additionally, the BNC-GO-NBC displayed the potential for regeneration, with the ability to be recycled up to five times. Further, the antibacterial activity, cell cytotoxicity and oxidative stress assays of the BNC-GO-NBC revealed its non-cytotoxic nature. The findings of the present investigation evidently suggest the potentiality of BNC-GO-NBC in the application of dye adsorption and other environmental applications.

10.
3 Biotech ; 12(1): 13, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34966636

RESUMO

In the present study, the efficiency of four different strains of Pseudomonas aeruginosa and their biosurfactants in the bioremediation process were investigated. The strains were found to be capable of metabolizing a wide range of hydrocarbons (HCs) with preference for high molecular weight aliphatic (ALP) over aromatic (ARO) compounds. After treating with individual bacteria and 11 different consortia, the residual crude oils were quantified and qualitatively analyzed. The bacterial strains degraded ALP, ARO, and nitrogen, sulphur, oxygen (NSO) containing fractions of the crude oil by 73-67.5, 31.8-12.3 and 14.7-7.3%, respectively. Additionally, the viscosity of the residual crude oil reduced from 48.7 to 34.6-39 mPa s. Further, consortium designated as 7 and 11 improved the degradation of ALP, ARO, and NSO HCs portions by 80.4-78.6, 42.7-42.4 and 21.6-19.2%, respectively. Moreover, addition of biosurfactant further increased the degradation performance of consortia by 81.6-80.7, 43.8-42.6 and 22.5-20.7%, respectively. Gas chromatographic analysis confirmed the ability of the individual strains and their consortium to degrade various fractions of crude oil. Experiments with biosurfactants revealed that polyaromatic hydrocarbons (PAHs) are more soluble in the presence of biosurfactants. Phenanthrene had the highest solubility among the tested PAHs, which further increased as biosurfactant doses raised above their respective critical micelle concentrations (CMC). Furthermore, biosurfactants were able to recover 73.5-63.4% of residual oil from the sludge within their respective CMCs. Hence, selected surfactant-producing bacteria and their consortium could be useful in developing a greener and eco-sustainable way for removing crude oil pollutants from soil.

11.
Chemosphere ; 273: 129677, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33503526

RESUMO

Recovery and recycle of wastewater are essential because of the need of huge quantities of water everywhere in this world. Presence of heavy metals in wastewater such as iron (Fe), molybdenum (Mo), manganese (Mn), zinc (Zn), nickel (Ni), copper (Cu), vanadium (V), cobalt (Co), tungsten (W), chromium (Cr), arsenic (As), silver (Ag), antimony (Sb), cadmium (Cd), mercury (Hg), lead (Pd), uranium (U), etc is the serious environmental issues and risk for human and animal health. Adsorbents are simple and low-cost methods to treat the pollutants and heavy metals of wastewater. The adsorbents are capable to treat the wastewater prepared from different wastes such as domestic, agricultural, industrial, animal and marine waste etc. In recent years, novel nanomaterials are also used as adsorbents which enhance the treatment efficiency of wastewater. Adsorption is a mass transfer phenomenon revolving shift of elements from a fluid to a solid phase based on the concentration gradient. The mechanism which helps in separation of contaminants from the effluent and the factors governing the efficiency of adsorption are discussed elaborately.


Assuntos
Metais Pesados , Nanoestruturas , Animais , Cromo/análise , Humanos , Metais Pesados/análise , Águas Residuárias , Zinco/análise
12.
Environ Sci Pollut Res Int ; 28(8): 9338-9345, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33141383

RESUMO

This study is focused on polymeric coatings on fly ash concrete submerged under seawater. The specimens were casted and coated with acrylic resin and epoxy resin of three layers each. The mechanical, durability, and microstructural properties of coated and uncoated fly ash concrete specimen were studied as pre- and post-exposed in seawater. Fly ash concrete coated with epoxy and acrylic had attained more strength compared to uncoated specimens. An increased strength in coated specimens and a decrease in value were observed in uncoated fly ash concrete specimens during split tensile strength. Coated specimens showed less reduction in pH value as compared to uncoated specimens. Rapid chloride permeability test (RCPT) analysis confirmed that epoxy and acrylic-coated concrete specimens appear to be denser than uncoated specimens leading to more resistance against the penetration of aggressive chemicals. The X-ray diffraction (XRD) comparative analysis of 56 and 90 days acrylic resin and epoxy resin-coated and uncoated specimen showed higher intensity in 90 days coated specimens than the uncoated specimens. Field emission scanning electron microscope (FESEM) investigation of uncoated 56 and 90 days concrete specimens subjected to seawater demonstrated dense appearance of hydrated products, whereas epoxy and acrylic-coated specimens were verified with no visible micro-cracks or holes on the surface, even at higher magnification. The epoxy and acrylic-coated fly ash concrete showed high physical strength and good bonding with concrete and will be appropriate for construction.


Assuntos
Cinza de Carvão , Materiais de Construção , Resinas Acrílicas , Água do Mar , Resistência à Tração
13.
Microbiol Res ; 244: 126666, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33338970

RESUMO

ß-lactamase inhibitors are potent synergistic drugs to deteriorate the multidrug-resistant bacteria. Here, we report the ß-lactamase inhibitory ability of kalafungin isolated from a marine sponge derived Streptomyces sp. SBRK1. The IC50 value of the kalafungin was calculated as 225.37 ± 1.95 µM against ß-lactamase. The enzyme kinetic analysis showed the Km value of 3.448 ± 0.7 µM and Vmax value of 215.356 ± 8 µM/min and the inhibition mechanism was identified as uncompetitive type. Along with the antibacterial activity, the cell surface analysis of kalafungin treated Staphylococcus aureus cells revealed destruction of cell membrane in response to ß-lactamase inhibition. Molecular docking studies have confirmed the binding property of kalafungin against ß-lactamase with two hydrogen bonds. In vivo efficacy studies in the zebrafish model by green fluorescent protein expressing S. aureus infection, survival, safety and behavioral profile were reported. The toxicity and anti-infection revealed that the compound was evidently active and safe to all organs. In conclusion, this is the first report on kalafungin with ß- lactamase inhibition and suggests that kalafungin may useful for synergic antibacterial therapy with ß-lactam drugs to overcome ß-lactamase-based resistance of any bacterial pathogens.


Assuntos
Antibacterianos/administração & dosagem , Proteínas de Bactérias/metabolismo , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/fisiologia , Streptomyces/química , Inibidores de beta-Lactamases/administração & dosagem , Animais , Antibacterianos/química , Proteínas de Bactérias/química , Modelos Animais de Doenças , Humanos , Cinética , Simulação de Acoplamento Molecular , Naftoquinonas/administração & dosagem , Naftoquinonas/química , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/enzimologia , Streptomyces/genética , Streptomyces/isolamento & purificação , Inibidores de beta-Lactamases/química , beta-Lactamases/química , beta-Lactamases/metabolismo
14.
Environ Toxicol Chem ; 40(12): 3306-3316, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-33289939

RESUMO

Contamination of agricultural soil with cadmium (Cd) has become a global concern because of its adverse effects on ecohealth and food safety. Soil amendment with biochar has become one of the phytotechnologies to reduce soil metal phyto-availability and its potential risks along the food chain. Biochar, derived from cocoa pod, was evaluated in soil Cd fractions (exchangeable, reducible, oxidizable, and residual) by modified Commission of the European Communities Bureau of Reference sequential extraction and its efficacy to ameliorate Cd toxicity to soil enzymes and leaf bioactive compounds. A pot experiment was conducted using Cd-spiked soil at 10 mg/kg with tomato (Solanum lycopersicum L.) at a biochar application rate of 1 and 3% (w/w) for 6 wk. The addition of biochar significantly reduced (p < 0.05) the exchangeable, reducible, and residual fractions by at least approximately 23%, with a consequential decrease in Cd root uptake and transport within tomato tissues. The activity of soil enzymes (catalase, dehydrogenase, alkaline phosphatase, and urease) was affected by Cd toxicity. However, with the exception of dehydrogenase, biochar application significantly enhanced the activity of these enzymes, especially at the 3% (w/w) rate. As for the secondary metabolites we studied, Cd toxicity was observed for glutathione, terpenoids, and total phenols. However, the biochar application rate of 1% (w/w) significantly ameliorated the effects of toxicity on the secondary metabolites. In conclusion, biochar demonstrated the potential to act as a soil amendment for Cd immobilization and thereby reduce the bioavailability of Cd in soil, mitigating food security risks. Environ Toxicol Chem 2021;40:3306-3316. © 2020 SETAC.


Assuntos
Poluentes do Solo , Solanum lycopersicum , Cádmio/análise , Carvão Vegetal/farmacologia , Solanum lycopersicum/metabolismo , Solo , Poluentes do Solo/análise
15.
Environ Sci Pollut Res Int ; 27(33): 41372-41380, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32681340

RESUMO

Sulfate attack on concrete structures is a major durability concern wherein concrete interacts with marine water, swamp water, groundwater, sewage water, freshwater, etc. In this study, the supplementary cementitious materials such as fly ash (FA) and nanoparticles are together incorporated into conventional concrete aiming to enhance the resistance of concrete against the penetration of sulfates. The present work is focused to understand the degradation in FA concrete modified with nanoparticles by surface sulfate attack. Concrete mix such as FA and FA modified with 2 wt% nano-TiO2 (FAT), nano-CaCO3 (FAC), and 1:1 ratio of nano-TiO2 to nano-CaCO3 (FATC) was fabricated. The specimens were exposed in 3% of ammonium and sodium sulfate for 90 days. The deterioration effects and changes in microstructural properties in all the specimens were comparatively studied. Results showed FAT, FAC, and FATC concrete have been deteriorated in ammonium and sodium sulfate solution compared with FA concrete. Partial replacement of cement with fly ash decreases the quantity of freely available reactive aluminates. Consumption of free lime by the fly ash prevents to react with sulfate. The enhanced properties of fly ash concrete against sulfate attack could be achieved with less C3A content thus reducing the available Ca(OH)2 and reducing the possibility of development of deleterious ettringite and gypsum.


Assuntos
Cinza de Carvão , Nanopartículas , Materiais de Construção , Esgotos , Sulfatos
16.
J Biotechnol ; 310: 54-61, 2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-32014560

RESUMO

The study was conducted to investigate the effects of foliar-intervention of nano-TiO2 on Cd toxicity in cowpea plants. Cowpea plants were exposed to Cd toxicity at 10 mg/kg soil for 21 days and afterwards, subjected to six episodes of foliar application of nano-TiO2 intervention. Results showed that foliar-applied nano-TiO2 significantly promoted chlorophyll b and total chlorophyll contents after Cd stress as compared to Cd-stressed plants without the intervention. Interestingly, Cd contents of roots, shoots and grains were significantly reduced (p < 0.05) after nano-TiO2 sprays compared to Cd-stressed plants. However, the Cd contents in edible tissues (leaves and seeds) after interventions remained above recommended threshold. Furthermore, nano-TiO2 interventions promoted stress enzymes activity in both roots and leaves as well as increased Zn, Mn and Co levels in seeds compared to Cd-stressed plants without intervention. Estimated daily intake of Cd in leaves and seeds for adult subpopulation exceeded the WHO recommended daily intake by some folds in Cd-stressed and nano-TiO2-treated plants. The health risk quotient (HQ) for adult subpopulation exceeded unitary in seeds from nano-TiO2 treatments (HQ = 1.75 and 1.96, respectively) while no potential risk was obtained for leaves. Overall, foliar application of nano-TiO2 portends significant ameliorative potential for Cd toxicity in cowpea plants.


Assuntos
Cádmio/toxicidade , Fibras na Dieta , Nanopartículas/efeitos adversos , Estresse Fisiológico/efeitos dos fármacos , Titânio/toxicidade , Vigna/metabolismo , Raízes de Plantas/metabolismo , Brotos de Planta/metabolismo , Sementes/metabolismo
17.
J Biomol Struct Dyn ; 38(5): 1448-1466, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31007134

RESUMO

Nonstructural protein 5B (NS5B), the RNA-dependent RNA polymerase of Hepatitis C Virus (HCV), plays a key role in viral amplification and is an attractive and most explored target for discovery of new therapeutic agents for Hepatitis C. Though safe and effective, NS5B inhibitors were launched in 2013 (Sovaldi) and 2014 (Harvoni, Viekira Pak), the high price tags of these medications limit their use among poor people in developing countries. Hence, still there exists a need for cost-effective and short duration anti-HCV agents especially those targeting niche patient population who were non-respondent to earlier therapies or with comorbid conditions. The present study describes the discovery of novel non-nucleoside (NNI) inhibitors of NS5B using a series of rational drug design techniques such as virtual screening, scaffold matching and molecular docking. 2D and 3D structure based virtual screening technique identified 300 hit compounds. Top 20 hits were screened out from identified hits using molecular docking technique. Four molecules, that are representative of 20 hits were evaluated for binding affinity under in vitro conditions using surface plasmon resonance-based assay and the results emphasized that compound with CoCoCo ID: 412075 could exhibit good binding response toward NS5B and could be a potential candidate as NS5B inhibitor.Communicated by Ramaswamy H. Sarma.


Assuntos
Hepacivirus , Hepatite C , Sítio Alostérico , Antivirais/farmacologia , Antivirais/uso terapêutico , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/uso terapêutico , Hepatite C/tratamento farmacológico , Humanos , Simulação de Acoplamento Molecular , Proteínas não Estruturais Virais
18.
J Nanosci Nanotechnol ; 9(9): 5480-3, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19928248

RESUMO

Biofouling is one of the major impediment in the use of titanium, which is otherwise excellent material with respect to corrosion resistance and mechanical properties, for seawater-cooled condensers of power plants. The routine chlorination treatment and sponge ball cleaning may not be successful to keep the titanium condenser tube clean over a period extending to years. This brings into focus the relevance of surface modification of titanium to improve the antimicrobial properties, which can effectively supplement the present treatment programmes. In this study antimicrobial thin film of copper (Cu) is developed on titanium surfaces, as copper is known to be very toxic to microorganisms and effectively kills most of the microbes by blocking the respiratory enzyme system. The preparation of nanocrystalline thin films of copper on titanium surfaces was done by pulsed DC magnetron-sputtering technique. Then this thin film was characterized using Glancing Incidence X-ray Diffraction (GIXRD) and Atomic Force Microscopy (AFM). Antimicrobial properties of these specimens were evaluated by exposure studies in seawater. Results showed two order decrease in the bacterial density on copper coated surface and epifluorescence micrographs depicted very few fluorescing cells and no biofilm formation clearly demonstrating the superior antibacterial capability of this nanocrystalline copper thin film.


Assuntos
Cobre , Titânio , Incrustação Biológica , Cobre/química , Microscopia de Força Atômica , Propriedades de Superfície , Titânio/química , Difração de Raios X
19.
Biofouling ; 25(8): 705-10, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20183129

RESUMO

Biofouling, especially microfouling, is a major concern with the use of titanium (Ti) in the marine environment as a condenser material in cooling water systems. Earlier, copper-nickel (Cu/Ni) alloys were extensively used in marine environments due to their high corrosion and biofouling resistance. However, the choice of condenser material for the new fast breeder reactor in Kalpakkam is Ti to avoid steam side corrosion problems, which may pose a threat to steam generator parts having sodium as the secondary coolant. This study evaluates the surface modification of Ti using nano films of copper (Cu) and nickel (Ni) to utilize the antibacterial property of copper ions in reducing microfouling. The surface modification of Ti was carried out by the deposition of a Cu/Ni bilayer and (Cu/Ni)(10) multilayer films using a pulsed laser deposition technique. Various surface characterization studies revealed that the deposited Cu/Ni films were thin and nanocrystalline in nature. The antibacterial properties were evaluated using total viable count and epifluorescence microscopic techniques. The results showed an apparent decrease in bacterial attachment on multilayered and bilayered Cu/Ni thin films on Ti surfaces. Comparative studies between the two types of films showed a bigger reduction in numbers of microorganisms on the multilayers.


Assuntos
Antibacterianos/farmacologia , Bactérias , Biofilmes , Cobre/farmacologia , Nanoestruturas/química , Níquel/farmacologia , Titânio/farmacologia , Antibacterianos/química , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Cobre/química , Lasers , Biologia Marinha/métodos , Teste de Materiais , Microscopia de Fluorescência , Nanopartículas , Níquel/química , Propriedades de Superfície , Titânio/química
20.
Environ Technol ; 40(4): i-xi, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30112961

RESUMO

Concrete structures develop biofilms when exposed to various environments. At a certain stage, the microbial films destroy the concrete structures leading to significant deterioration. Culture-dependent techniques give an incomplete picture of the microbial communities on the concrete surface. Culture-independent techniques or molecular biological tools pave a new way to analyse microbial communities involved in concrete biodeterioration. This study highlights the need to 'build' a database, for Microbiologically Influenced Concrete Corrosion (MICC) involving microbial groups that are being identified using culture-dependent and independent techniques. The role of molecular tools such as 16S rRNA sequencing, denaturing gradient gel electrophoresis (DGGE), Fluorescent in situ hybridization (FISH), Real-time Polymerase Chain Reaction (RT-PCR), microarray analysis, 2-Dimensional gel electrophoresis (2-DE) in analysing microbial communities on the concrete structures have been reviewed in this paper.

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