Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 32
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Br J Neurosurg ; 37(1): 35-40, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33349075

RESUMO

BACKGROUND: Gliomas are the most aggressive form of brain tumors responsible for the majority of brain cancer related deaths. Interleukin (IL)-6, 10 and tumor necrosis factor (TNF)- α are tumor specific proteins that are expressed in gliomas. This study aims to estimate the pre- and postoperative levels of serum markers of these cytokines to evaluate any bearing with its grade and volume. METHODS: Prospective analysis of 80 patients of newly-diagnosed gliomas of any grade was carried out. Pre- and postoperative blood samples day one, one month and at 3rd month of surgery was taken and levels of IL-6, 10 and TNF- α measured and matched with 20 healthy controls. RESULTS: Of the 80 patients, 3 patients had pilocytic astrocytoma, 4 had ganglioglioma, 9 had oligodendroglioma, 17 had diffuse astrocytoma, 5 had anaplastic astrocytoma while 43 had glioblastoma. Preoperative levels of IL-6 and TNF- α was found to be markedly raised in high grade gliomas. Positive correlation was seen between IL-6 with the grade of tumor and high-grade tumors were seen to be more significantly correlated with IL-6. However, preoperative IL-10 in both low and high grade of gliomas did not show any correlation with the volume and grade of tumor. CONCLUSION: High level of IL-6 and TNF-α in peripheral blood in patients of high-grade gliomas provides clue to the invasiveness of the disease which can be useful for understanding the premorbid development of tumor and perhaps extrapolating to ongoing tumor response to treatment.


Assuntos
Astrocitoma , Neoplasias Encefálicas , Glioma , Humanos , Estudos Prospectivos , Citocinas , Interleucina-6 , Astrocitoma/cirurgia , Astrocitoma/patologia , Glioma/cirurgia , Glioma/patologia , Neoplasias Encefálicas/cirurgia , Neoplasias Encefálicas/patologia , Fator de Necrose Tumoral alfa
2.
Pak J Pharm Sci ; 34(1(Supplementary)): 215-223, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34275845

RESUMO

The main cause of hepatitis C is hepatitis C virus or HCV and for the cure of hepatitis C, NS3/4A protease has been found an important and emerging target. A number of HCV NS3/4A protease inhibitors have been discovered which have shown subsequent reduction in reducing the viral load leading to this infection however they are still undergoing clinical trials for improvement. Bacterial proteases are of great pharmaceutical importance and have a key role in various biological processes and in life cycle of several pathogens. The current study was planned to explore hexapeptides derived from conserved regions of bacterial proteases for their potential in blocking the NS3 protease activity of HCV which would finally inhibit HCV multiplication. For this, a novel protease gene nprB was isolated from a thermophilic bacterium Streptomyces thermovulgaris and bioinformatics analyses were performed. PCR amplification and sequencing of nprB gene indicated an open reading frame of 178 aa (20191.18 Dalton).The peptide GGVHIN was the top ranked with minimum S-score of -17.21) followed by hexapeptides VDAHAN, GVGREA, GALNES and VHINSS with their S-scores of -14.73, -13.78, -10.72 and -10.70, respectively. A phylogram was also reconstructed to reveal evolutionary relationships of nprB with its various homologs. The provided data will serve as a background to further reveal pharmaceutical and biotechnological importance of this novel protease gene from S. thermovulgaris in future.


Assuntos
Proteínas de Bactérias/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Metaloendopeptidases/metabolismo , Peptídeos/metabolismo , Inibidores de Proteases/metabolismo , Streptomyces/genética , Proteínas não Estruturais Virais/metabolismo , Sequência de Aminoácidos , Antivirais/metabolismo , Antivirais/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/farmacologia , Sequência Conservada , Metaloendopeptidases/genética , Metaloendopeptidases/farmacologia , Simulação de Acoplamento Molecular , Peptídeos/genética , Peptídeos/farmacologia , Inibidores de Proteases/farmacologia
3.
Pak J Pharm Sci ; 33(1(Special)): 459-468, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32173644

RESUMO

We have developed a new analytical method for simultaneous determination of Metronidazole and Furazolidone by High Performance Liquid Chromatography (HPLC). The method is coupled to double salting-out assisted liquid-liquid extraction (SALLE) which facilitates the detection and quantification of Metronidazole and Furazolidone in different dosage forms by subsequent HPLC analysis. Extraction parameters such as solvent, pH and salt concentration are optimized and liquid liquid extraction showed efficiency up to 102% and 100% for Metronidazole and Furazolidone respectively in chloroform, at pH 3 and low salt concentration (0.5g KCl and 0.5 gNaNO3). The designed simultaneous analytical method is further validated and Metronidazole and Furazolidone showed linearity upto R20.994 and 0.9936 respectively. LOD was 2.1µg/ml, 1.5µg/ml and LOQ was 21.1µg/ml, 15.2µg/ml for metronidazole benzoate and furazolidone. Precision of the method is 1.84% (RSD) and 1.72% (RSD) for Metronidazole and Furazolidine respectively. Moreover, accuracy is measured in terms of percent recovery which is more than 100% for both analytes under optimized conditions. Finally, robustness is evaluated by changing the flow rate and detection wavelength which is also obtained within permissible limit. This indicates that the proposed method is simple, efficient and shows excellent recoveries for simultaneous determination of Metronidazole and Furazolidone in different dosage forms and Industrial effluents.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Furazolidona/isolamento & purificação , Resíduos Industriais/análise , Extração Líquido-Líquido/métodos , Metronidazol/isolamento & purificação , Indústria Farmacêutica , Espectrofotometria Ultravioleta
4.
Pak J Pharm Sci ; 33(5(Supplementary)): 2361-2369, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33832913

RESUMO

Bacterial proteases are of great pharmaceutical importance and have a key role in various biological processes and in life cycle of several pathogens. New technology used for rational protein engineering as well improved delivery options will expand the potential pharmaceutical applications of proteases. The catalytic proteases belong to metalloproteases (EC.3.4.24) that comprise thermo lysine. The metalloproteases and their homologs have many important biotechnological and therapeutic applications. In the present study, a novel protease gene nprB was isolated from a thermophilic bacterium Streptomyces thermovulgaris and bioinformatics analyses were performed. PCR amplification and sequencing of nprB gene indicated an open reading frame of 178 aa (20191.18 Dalton). Based on protein sequence homology as well as conserved motifs and PTF domain the protein is characterized as a thermo lysine-like protease and is a member of M4 family of metalloproteases. Different bioinformatics tools such as ProtParam, SOPMA, signalP4.1 and ProDom from the ExPAsy server were used for structural and functional analyses. A phylogram was also reconstructed to reveal evolutionary relationships of nprB with its various homologs. The provided data will serve as a background to further reveal pharmaceutical and biotechnological importance of this novel protease gene from S. thermovulgaris in future.


Assuntos
Proteínas de Bactérias/metabolismo , Metaloproteases/farmacologia , Streptomyces/enzimologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/isolamento & purificação , Biologia Computacional , Estabilidade Enzimática , Metaloproteases/genética , Metaloproteases/isolamento & purificação , Modelos Moleculares , Filogenia , Conformação Proteica , Streptomyces/genética , Relação Estrutura-Atividade , Especificidade por Substrato
5.
Langmuir ; 35(27): 8996-9003, 2019 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-31189312

RESUMO

Tainting of waterbodies with noxious industrial waste is the gravest environmental concern of the day that continues to wreak inevitable havoc on human health. To cleanup these hard-to-remove life-threatening water contaminants, we have prepared hierarchically porous poly(acrylic acid) beads by emulsion templating. These emulsion-templated macroporous polymer beads not only mediate the synthesis of Fe3O4 nanoparticles inside their porous network using a coprecipitation approach but, in turn, create diverse anchoring sites to immobilize an additional poly(acrylic acid) active layer onto the nanocomposite beads. These post-synthetically modified nanocomposite beads with macropores and abundant acrylic acid moieties offer the ready mass transfer and fair advantage of relatively higher overall negative charge to efficiently adsorb lead [Pb(II)] and crystal violet with impressive performance-even superior to many of the materials explored in this regard so far. Furthermore, the strong entanglement of nanoparticles in the porous polymeric scaffolds tackles the curb of trade-off between all-round effective remediation and secondary pollution and the millimeter size eases their processing and recovery during the adsorption tests, thereby making these materials practically worthwhile.

6.
Langmuir ; 35(40): 13165-13173, 2019 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-31525878

RESUMO

Emulsion templating has emerged as a cutting-edge technique to prepare a wide array of porous polymer-metal nanocomposites with intriguing properties. Using this strategy, we set out to prepare novel hierarchically porous poly(vinylsulfonic acid) beads, which were then used for the in situ production of silver nanoparticles to obtain poly(vinylsulfonic acid)-Ag nanocomposite beads via a facile approach. Owing to their multimodal macro-meso-/microporosity that accounts for their decent BET surface areas (170.75-197.74 m2/g) and easier mass diffusion and transport together with the synergistic benefits of very small silver nanoparticles (down to ∼3.77 nm), the nanocomposite beads are found effective to remove Hg(II) and RhB and to kill Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria. The adsorption capacities (167.98-190.58 mg/g) of these materials for Hg(II) surpass some recently reported benchmark materials. The larger size (1.56 ± 0.20-1.50 ± 0.14 mm) of the beads that helps favor the handling and subsequent recovery for recycling is also very useful to further broaden the horizons of these materials to develop decentralized water treatment systems.

7.
Pak J Pharm Sci ; 31(1): 153-157, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29348097

RESUMO

In this study we have reported a new, fast and extraction free spectrophotometric procedure for the assessment of caroverine in pharmaceutical raw and tablet dosage forms. In the reported visible spectrophotometric procedure tungstate in Folin-Ciocalteu phenol reagent is reduced in alkaline medium and produces the blue colored chromogen that shows Λmax at 740nm with the calibration range of 2-28µg/ml. The LOD and LOQ values are 1.15 and 3.81µg/ml respectively. The newly developed analytical procedure is used to determine caroverine in raw material of and commercial tablets dosage forms. The spectrophotometric method represented in this study is simple, rapid and extraction free. It may easily be utilized for the determination of caroverine in pharmaceutical laboratories for quality control and stability studies purpose.


Assuntos
Composição de Medicamentos/normas , Molibdênio/química , Quinoxalinas/análise , Quinoxalinas/normas , Espectrofotometria/métodos , Compostos de Tungstênio/química , Estabilidade de Medicamentos , Excipientes/análise , Indicadores e Reagentes , Limite de Detecção , Estrutura Molecular , Comprimidos
8.
Guang Pu Xue Yu Guang Pu Fen Xi ; 37(1): 306-11, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30221908

RESUMO

A comparative study of Cannabis sativa (Hemp) essential constituents obtained by using Supercritical Fluid Extraction (SCFE), Steam Distillation (SD) and Hydrodistillation (HD) is presented here. The optimized extraction temperatures were 130,110 and 50 ℃ for hydrodistillation, steam distillation and supercritical fluid extraction respectively. The essential oil of C. sativa was analyzed by using Gas chromatography mass spectrometry (GC-MS). A total of 33, 30 and 31 components have been identified in HD, SD and SCFE respectively. Yield of essential oil using SCFE (0.039%) was more than HD (0.025%) and SD (0.035%) extraction respectively. The main component of sesquiterpenes obtained by hydrodistillation at 130 ℃ with their percentages included caryophyllene (40.58%), trans-α-bergamotene (5.41%), humulene (10.97%), cis-ß-farnesene (8.53%) and monoterpenes included α-pinene (2.13%), d-limonene (6.46%), p-cymol (0.65%) and cineole (2.58%) respectively. The main component of sesquiterpenes obtained by SD steam distillation at 110 ℃ including caryophyllene (38.60%) trans-α-bergamotene (4.22%), humulene (10.26%), cis-ß-farnesene (6.67%) and monoterpenes included α-pinene (3.21%), d-limonene (7.07%), p-cymol (2.59%) and cineole (3.88%) whereas the more percentages of major components were obtained by SCFE at 50 ℃ included caryophyllene (44.31%), trans-α-bergamotene (6.79%), humulene (11.97%) cis-ß-farnesene (9.71%) and monoterpenes included α-pinene (0.45%), d-limonene (2.13%) p-cymol (0.19%) and cineole (1.38 %) respectively. We found yield/efficiency, chemical composition, quality of the essential oils by supercritical fluid extraction superior in terms of modern, green, saving energy and a rapid approach as compared to traditional techniques.


Assuntos
Cannabis/química , Óleos Voláteis/química , Cromatografia com Fluido Supercrítico , Destilação , Cromatografia Gasosa-Espectrometria de Massas , Limoneno/análise , Monoterpenos/análise
9.
Pak J Pharm Sci ; 27(2): 255-60, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24577911

RESUMO

A fast, sensitive and extraction free spectrophotometric method for the quantitative determination of citalopram hydrobromide in pharmaceutical raw and tablet formulations has been proposed. The newly proposed method is based on the charge transfer reaction between citalopram as electron donor and chloranil as electron acceptor. The charge transfer complex of citalopram and chloranil shows λ(max) at 550 nm in methanol. The experimental conditions such as reaction time, temperature, stoichiometry of the colored complex have been optimized. The developed method allows the determination of citalopram hydrobromide over a concentration range of 1-25 mg/ ml. The proposed method is used to determine the citalopram in tablet dosage forms. The results of proposed method are compared to the official USP method. The newly developed method is accurate, reproducible and easy to perform. It does not require stringent experimental conditions. No interference has been observed for excipients and additives in tablet formulations.


Assuntos
Cloranila/química , Citalopram/análise , Inibidores Seletivos de Recaptação de Serotonina/análise , Calibragem , Química Farmacêutica , Cromatografia Líquida de Alta Pressão , Cor , Indicadores e Reagentes , Soluções Farmacêuticas , Padrões de Referência , Reprodutibilidade dos Testes , Espectrofotometria Infravermelho , Comprimidos
10.
BMC Chem ; 18(1): 53, 2024 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-38493163

RESUMO

This study encompasses a quick, efficient, repeatable and reproducible analytical method for simultaneous determination of Bromoxynil (3, 5-Dibromo-4-hydroxybenzonitrile) and MCPA (2-methyl-4-chlorophenoxyacetic acid) using RP-HPLC with UV-Detector. Bromoxynil + MCPA is one of the most selective post emergent herbicide formulations for the control of important broad leaf weeds infesting small grains (wheat, barley, oats, rye), conservation reserve program areas and grass grown for seed. Optimum weed control is achieved when Bromoxynil + MCPA is applied to actively growing weed seedlings. So, a simple, repeatable, reproducible and efficient simultaneous analytical method was developed for Bromoxynil + MCPA. The developed method was applied for the detection and quantitation of these pesticides in formulations and raw materials with excellent recoveries. It was validated according to ICH Guidelines with excellent linearity R2 = 0.992 for Bromoxynil and 0.998 for MCPA. For Bromoxynil, LOD = 1.57 mg/L and LOQ = 5.22 mg/L while for MCPA the LOD = 1.08 mg/L and LOQ = 3.62 mg/L was found. The proposed method has shown high precision (RSD %) 0.06% and 0.11% for Bromoxynil and MCPA respectively while the trueness has been calculated in terms of recovery percentage obtained as "mean value of Bromoxynil 99.53% and MCPA 100.10%" which is excellent under optimized conditions. For repeatability and reproducibility, five replicate readings of standard and sample were taken and had found within acceptable limits of relative standard deviation (RSD ≤ ± 2%). Finally, the robustness of the developed method was determined by changing flow rate and mobile phase ratios that has found within the permissible limits (% RSD NMT 1.5). So, the proposed analytical method has found to be more precise, valid and accurate at commercial scale.

11.
Pak J Pharm Sci ; 25(2): 377-80, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22459465

RESUMO

A study was carried out to investigate the concentrations of macro-elements (Na(+), K(+) and Mg(+2)) in twelve commercially available pharmaceutical preparations used as sex stimulant, by Atomic Absorption Spectrophotometer. A wet digestion method was adopted to prepare the samples. The results indicated that sodium concentration was maximum (3702 ± 29 µg g(-1)) in LB and minimum (495 ± 06 µg g(-1)) in H-E-H. Potassium concentration was maximum (6337 ± 13 µg g(-1)) in NBA while minimum (150 ± 06 µg g(-1)) in ZGRA. Magnesium concentration was maximum in V-100 (9226 ± 11 µg g(-1)) and minimum in FGRA (1194 ± 25 µg g(-1)). The concentration of macro-elements in the imported herbal preparations was in the order of Mg

Assuntos
Magnésio/análise , Preparações Farmacêuticas/análise , Potássio/análise , Sódio/análise , Espectrofotometria Atômica
12.
Ethiop J Health Sci ; 32(5): 955-962, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36262707

RESUMO

Background: The aim of this pilot study is to obtain preliminary results comparing topical oxygen therapy (TOT) and vacuum assisted closure (VAC) in terms of its ability to accelerate wound healing. Methods: This non-randomised prospective study included patients with age 16-50 years, wound size ≥ 16cm2 and present below knee joint within seven days of occurrence. Bates-Jensen wound assessment tool (BWAT) was used for evaluation at 8-day interval along with percent area reduction at final follow up. Results: Mean number of cycles required in VAC and TOT group were 1.97 (range 1-3) and 2.1 (range 1-3) (each cycle of 5 days) per patient respectively. Percent area reduction was significantly higher in the VAC group (34±9.7%) than TOT (11.3±3.8%) group at final follow up (p<0.05). TOT patients had better improvement in epithelialization compared to VAC at last follow up. More extensive debridement was needed in patients of TOT than VAC. There was no significant difference between final score in both groups. Conclusions: TOT appears to be comparable to well-established VAC in treatment of fresh traumatic wounds below the knee joint. Further large scale, multicentric and randomised studies comparing both these modalities of treatment should be the way forward.


Assuntos
Tratamento de Ferimentos com Pressão Negativa , Humanos , Adolescente , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Tratamento de Ferimentos com Pressão Negativa/métodos , Desbridamento/métodos , Estudos Prospectivos , Oxigênio/uso terapêutico , Projetos Piloto , Cicatrização , Infecção da Ferida Cirúrgica , Resultado do Tratamento
13.
ACS Appl Mater Interfaces ; 13(23): 27400-27410, 2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34081850

RESUMO

Emulsion template-guided strategy has been used to produce porous architectures with exquisite structure, tailored morphology, and exclusive features for ubiquitous applications. Notwithstanding, the practical water remediation is often marred by their transport-limited behavior and fragility. To circumvent these conundrums, we prepared hierarchically porous poly(acrylic acid)-alumina nanocomposite beads by solidifying the droplets of emulsions jointly stabilized by the organic surfactants and alumina nanoparticles. By virtue of their positive charge, the alumina nanoparticles got entrapped within the poly(acrylic acid) scaffolds that excluded the risk of secondary contamination typically observed with conventional nanocomposites. Being amenable to surface modification, the carboxyl moieties of the beaded polymer were further exploited to covalently tether branched polyethylenimine throughout the exterior and interior surface of the porous matrix via a grafting-to approach. The macropores expedite an active fluid flow and easier adsorbate transport throughout the functionalized nanocomposites whose overall higher density of positive charge over a certain pH range electrostatically attracts and effectively adsorbs the negatively charged Cr(VI) complexes and anionic congo red ions/molecules from water. This proof-of-concept synthetic approach and postsynthetic modification offer an improved mechanical robustness to these macrosized multifunctional nanocomposite beads for their easier processing, thereby paving the way for the point-of-use water purification technology development.

14.
Adv Sci (Weinh) ; 8(22): e2102540, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34553500

RESUMO

Emulsion templating is at the forefront of producing a wide array of porous materials that offers interconnected porous structure, easy permeability, homogeneous flow-through, high diffusion rates, convective mass transfer, and direct accessibility to interact with atoms/ions/molecules throughout the exterior and interior of the bulk. These interesting features together with easily available ingredients, facile preparation methods, flexible pore-size tuning protocols, controlled surface modification strategies, good physicochemical and dimensional stability, lightweight, convenient processing and subsequent recovery, superior pollutants remediation/monitoring performance, and decent recyclability underscore the benchmark potential of the emulsion-templated porous materials in large-scale practical environmental applications. To this end, many research breakthroughs in emulsion templating technique witnessed by the recent achievements have been widely unfolded and currently being extensively explored to address many of the environmental challenges. Taking into account the burgeoning progress of the emulsion-templated porous materials in the environmental field, this review article provides a conceptual overview of emulsions and emulsion templating technique, sums up the general procedures to design and fabricate many state-of-the-art emulsion-templated porous materials, and presents a critical overview of their marked momentum in adsorption, separation, disinfection, catalysis/degradation, capture, and sensing of the inorganic, organic and biological contaminants in water and air.

15.
J Hazard Mater ; 161(1): 88-94, 2009 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-18502037

RESUMO

Studies on the biosorptive ability of Gossypium hirsutum (Cotton) waste biomass outlined that smaller size of biosorbent (0.355mm), higher biomass dose (0.20g), 5 pH and 100mg/L initial Pb(II) concentration were more suitable for enhanced Pb(II) biosorption from aqueous medium. The Langmuir isotherm model and pseudo second order kinetic model fitted well to the data of Pb(II) biosorption. Highly negative magnitude of Gibbs free energy (DeltaG degrees ) indicated that the process was spontaneous in nature. In addition to this surface coverage and distribution coefficient values of Pb(II) biosorption process were also determined. At optimized conditions Pb(II) uptake was more rapid in case of industrial effluents in comparison to synthetic solutions. FTIR spectroscopic analysis revealed that the main functional groups involved in the uptake of Pb(II) on the surface of G. hirsutum biomass were carboxyl, carbonyl, amino and alcoholic.


Assuntos
Biomassa , Fibra de Algodão/métodos , Substâncias Perigosas/análise , Substâncias Perigosas/metabolismo , Chumbo/análise , Chumbo/metabolismo , Poluentes Químicos da Água/análise , Concentração de Íons de Hidrogênio , Cinética , Sementes/química , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Poluentes Químicos da Água/metabolismo
16.
J Hazard Mater ; 156(1-3): 64-73, 2008 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-18242826

RESUMO

The present study reports the use of locally available fish (Labeo rohita) scales for Pb(II) removal from aqueous solutions under different experimental conditions. Maximum Pb(II) adsorption (196.8 mg g(-1)) occurred at pH 3.5. Pb(II) sorption was found to be pH, dose, initial metal concentration, contact time and shaking speed dependent while particle size and temperature independent. Experimental data of Pb(II) biosorption onto fish scales fitted well to Freundlich isotherm model in comparison to the model of Langmuir. The fast adsorption process in first 30 min followed by subsequent slow adsorption rate was suitably described by pseudo-second order model. In addition, this study was designed to evaluate the effect of physical and chemical pretreatments on surface properties of fish scales by the application of Fourier Transform Infrared (FTIR) Spectroscopic analysis. Physical pretreatments resulted in partial degradation of some functional groups. Alkaline pretreatments of fish scales did not have any significant influence on the nature of functional groups responsible for Pb(II) uptake, while acidic pretreatments resulted in degeneration of the most of functional groups on biosorbent cell wall. FTIR analysis confirmed the involvement of amino, carboxylic, phosphate and carbonyl groups in Pb(II) biosorption by fish scales.


Assuntos
Peixes/metabolismo , Chumbo/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Animais , Chumbo/química
17.
Environ Sci Pollut Res Int ; 25(24): 23657-23666, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29047055

RESUMO

The waste tyre and waste cooking oils have a great potential to be used as alternative fuels for diesel engines. The aim of this study was to convert light fractions of pyrolysis oil derived from Pakistani waste vehicle tyres and waste soybean oil methyl esters into valuable fuel and to reduce waste disposal-associated environmental problems. In this study, the waste tyre pyrolysis liquid (light fraction) was collected from commercial tyre pyrolysis plant and biodiesel was prepared from waste soybean oil. The fuel blends (FMWO10, FMWO20, FMWO30, FMWO40 and FMWO50) were prepared from a 30:70 mixture of waste tyre pyrolysis liquid and waste soybean oil methyl esters with different proportions of mineral diesel. The mixture was named as the fuel mixture of waste oils (FMWO). FT-IR analysis of the fuel mixture was carried out using ALPHA FT-IR spectrometer. Experimental investigations on a diesel engine were carried out with various FMWO blends. It was observed that the engine fuel consumption was marginally increased and brake thermal efficiency was marginally decreased with FMWO fuel blends. FMWO10 has shown lowest NOx emissions among all the fuel blends tested. In addition, HC, CO and smoke emissions were noticeably decreased by 3.1-15.6%, 16.5-33.2%, and 1.8-4.5%, respectively, in comparison to diesel fuel, thereby qualifying the blends to be used as alternative fuel for diesel engines.


Assuntos
Biocombustíveis , Gasolina , Eliminação de Resíduos/métodos , Culinária , Desenho de Equipamento , Gasolina/análise , Veículos Automotores , Óleos , Paquistão , Óleo de Soja/química , Espectroscopia de Infravermelho com Transformada de Fourier , Emissões de Veículos/análise
18.
RSC Adv ; 8(52): 29628-29636, 2018 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-35547285

RESUMO

Nano/microscale TiO2 materials and their composites have reached the pinnacle of their photocatalytic performances to destroy persistent organic pollutants and waterborne microorganisms, but their practical applications are limited by the drawbacks associated with their stability, leaching, processing and separation. To overcome these shortcomings, we have prepared hierarchically porous nanostructured TiO2 macrobeads via an exotemplating or nanocasting strategy by infiltrating the TiO2 sol into the emulsion-templated porous polyacrylamide scaffold followed by its gelation, drying and calcination. The nanoscale TiO2 building units tailor the shape of the porous polymeric network after calcination thereby retaining the macroscale morphology of polymer beads after template removal. A novel combination of the hierarchical macroporosity, orderly crystalline anatase nature, nanoscale feature and good surface area revealed by the relevant characterization tools makes these TiO2 scaffolds particularly effective for superior degradation of methylene blue with the enhanced rate constant and efficient disinfection of E. coli and S. aureus under UV light. The macrosize and mechanical stability of these purely TiO2 beaded architectures have several potential advantages over conventional TiO2 nanocomposites and slurry systems to address the inherent bottlenecks of secondary contamination, difficult operation and energy-intensive post-recovery processes that are indeed deemed to be the barriers to develop practically useful water treatment technologies.

19.
J Hazard Mater ; 139(2): 345-55, 2007 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-16860463

RESUMO

Cassia fistula is a fast-growing, medium-sized, deciduous tree which is now widely cultivated worldwide as an ornamental tree for its beautiful showy yellow flowers. Methods are required to reuse fallen leaves, branches, stem bark and pods when they start getting all over lawn. This investigation studies the use of these non-useful parts of C. fistula as naturally occurring biosorbent for the batch removal of Ni(II) in a well stirred system under different experimental conditions. The data showed that the maximum pH (pHmax) for efficient sorption of Ni(II) was 6 at which evaluated biosorbent dosage, biosorbent particle size, initial concentrations of Ni(II) and sorption time were 0.1 g/100 mL, <0.255 mm, up to 200 mg/L and 720 min, respectively. The experimental results were analyzed in terms of Langmuir and Freundlich isotherms. The Langmuir isotherm model fitted well to data of Ni(II) biosorption by C. fistula biomass as compared to the model of Freundlich. The kinetic studies showed that the sorption rates could be described better by a second order expression than by a more commonly applied Lagergren equation. The magnitude of the Gibbs free energy values indicates spontaneous nature of the sorption process. The sorption ability of C. fistula biomass for Ni(II) removal tends to be in the order: leaves

Assuntos
Cassia/metabolismo , Poluentes Ambientais/isolamento & purificação , Níquel/isolamento & purificação , Adsorção , Poluentes Ambientais/metabolismo , Concentração de Íons de Hidrogênio , Cinética , Níquel/metabolismo , Tamanho da Partícula , Casca de Planta/metabolismo , Folhas de Planta/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier
20.
ACS Appl Mater Interfaces ; 9(28): 24190-24197, 2017 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-28644011

RESUMO

Water, the driver of nature, has always been polluted by the blind hurling of highly toxic contaminants, but human-friendly science has continuously been presenting better avenues to help solve these challenging issues. In this connection, the present study introduces novel nanocomposites composed of emulsion-templated hierarchically porous poly(1-vinylimidazole) beads loaded with the silver nanoparticles generated via an in situ approach. These nanocomposites have been thoroughly characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, Brunauer-Emmett-Teller, and field emission scanning electron microscopy. The appropriate surface chemistry, good thermal stability, swelling behavior, porosity, and nanodimensions contributed to achieve very good performance in water treatment. Owing to their easier handling and separation, these novel nanocomposites are highly efficient to remove arsenic and eriochrome black T with decent adsorption capacities in addition to the inactivation and killing of Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA