Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
1.
Artigo em Inglês | MEDLINE | ID: mdl-39023728

RESUMO

Perovskites are an emerging material with a variety of applications, ranging from their solar light conversion capability to their sensing efficiency. In current study, perovskite nanocrystals (PNCs) were designed using theoretical density functional theory (DFT) analysis. Moreover, the theoretically designed PNCs were fabricated and confirmed by various characterization techniques. The calculated optical bandgap from UV-Vis and fluorescence spectra were 2.15 and 2.05 eV, respectively. The average crystallite size of PNCs calculated from Scherrer equation was 15.18 nm, and point of zero charge (PZC) was obtained at pH 8. The maximum eosin B (EB) removal efficiency by PNCs was 99.56% at optimized conditions following first-order kinetics with 0.98 R2 value. The goodness of the response surface methodology (RSM) model was confirmed from analysis of variance (ANOVA), with the experimental F value (named after Ronald Fisher) of 194.66 being greater than the critical F value F0.05, 14, 14 = 2.48 and a lack of fit value of 0.0587. The Stern-Volmer equation with a larger Ksv value of 1.303710 × 10 6 for Pb2+ suggests its greater sensitivity for Pb2+ among the different metals tested.

2.
Int J Biol Macromol ; 274(Pt 2): 133379, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38936571

RESUMO

Chitin is the second most abundant natural biopolymer, which is composed of N-acetyl glucosamine units linked by ß-(1 â†’ 4) Chitosan is an N-deacetylated product of chitin. Properties of chitosan and chitin, such as biocompatibility, non-toxic nature, and biodegradability, make them successful alternatives for energy and environmental applications. However, their low mechanical properties, small surface area, reduced thermal properties, and greater pore volume restrict the potential for adsorption applications. Multiple investigations have demonstrated that these flaws can be prevented by fabricating chitosan and chitin with carbon-based composites. This review presents a comprehensive analysis of the fabrication of chitosan/chitin carbon-based materials. Furthermore, this review examines the prevalent technologies of functionalizing chitosan/chitin biopolymers and applications of chitin and chitosan as well as chitosan/chitin carbon-based composites, in various environmental fields (mitigating diverse water contaminants and developing biosensors). Also, the subsequent regeneration and reuse of adsorbents were also discussed. Finally, we summarize a concise overview of the difficulties and potential opportunities associated with the utilization of chitosan/chitin carbon-based composites as adsorbents to remove water contaminants.


Assuntos
Carbono , Quitina , Quitosana , Adsorção , Quitosana/química , Carbono/química , Quitina/química , Biopolímeros/química , Poluentes Químicos da Água/química , Purificação da Água/métodos
3.
Chemosphere ; 360: 142408, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38789056

RESUMO

A massive amount of toxic substances and harmful chemicals are released every day into the outer environment, imposing serious environmental impacts on both land and aquatic animals. To date, research is constantly in progress to determine the best catalytic material for the effective remediation of these harmful pollutants. Hybrid nanomaterials prepared by combining functional polymers with inorganic nanostructures got attention as a promising area of research owing to their remarkable multifunctional properties deriving from their entire nanocomposite structure. The versatility of the existing nanomaterials' design in polymer-inorganic hybrids, with respect to their structure, composition, and architecture, opens new prospects for catalytic applications in environmental remediation. This review article provides comprehensive detail on catalytic polymer nanocomposites and highlights how they might act as a catalyst in the remediation of toxic pollutants. Additionally, it provides a detailed clarification of the processing of design and synthetic ways for manufacturing polymer nanocomposites and explores further into the concepts of precise design methodologies. Polymer nanocomposites are used for treating pollutants (electrocatalytic, biocatalytic, catalytic, and redox degradation). The three catalytic techniques that are frequently used are thoroughly illustrated. Furthermore, significant improvements in the method through which the aforementioned catalytic process and pollutants are extensively discussed. The final section summarizes challenges in research and the potential of catalytic polymer nanocomposites for environmental remediation.


Assuntos
Poluentes Ambientais , Recuperação e Remediação Ambiental , Nanocompostos , Polímeros , Recuperação e Remediação Ambiental/métodos , Catálise , Polímeros/química , Poluentes Ambientais/química , Nanocompostos/química , Oxirredução
4.
Chemosphere ; 334: 138923, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37178938

RESUMO

Perovskites overtaking simple metal oxides as solar light harvesting material due to their excellent photocatalytic efficiency and superior stability. An efficient visible light responsive, K2Ba0.3Cu0.7O3 single perovskites oxides (SPOs) photocatalyst was fabricated by a facile hydrothermal method. The fabricated SPOs was characterized by various techniques. SEM analysis confirm the cubic morphology of SPOs, the average length and diameter of SPOs were 27.84 and 10.06 µm calculated from SEM images. FT-IR analysis confirmed the presence of M-M and M - O bonds. EDX showed prominent peaks of the constituent elements. The average crystallite size of SPOs calculated by Scherrer and Williamson-Hall equation was 14.08 and 18.47 nm respectively. The optical band gap value lies in visible region of spectrum (2.0 eV) determined from the Tauce's plot. The fabricated SPOs was applied for photocatalytic degradation of methylene blue (MB) dye. Maximum degradation 98.09% of MB was achieved at 40 min irradiation time, 0.01 g catalyst dose, 60 mg L-1 MB concentration and pH 9. The photocatalytic degradation of MB follows first order kinetic. RSM modeling of MB removal was also caried out. Reduce quadratic model was best fitted model having F-value = 300.65, P-value = < 0.0001,R2 = 0.9897, predicted R2 = 0.9850 and adjusted R2 = 0.9864.


Assuntos
Óxidos , Luz Solar , Espectroscopia de Infravermelho com Transformada de Fourier , Óxidos/química , Luz , Catálise , Azul de Metileno/química
5.
Chemosphere ; 328: 138476, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36963573

RESUMO

The unplanned anthropogenic activities and raced industrial revolution detrimentally causes serious threat to terrestrial and aquatic life. A high discharge of wastewater from industries using dyes affects living organisms and the environment. This paper presents studies on polycationic selenides (PCS) synthesized by hydrothermal methods for photocatalytic degradation of dyes. The synthesized PCS were confirmed by various characterization techniques such as FTIR, SEM, EDX, UV/Vis, and XRD. The FTIR spectra revealed characteristic band at 843, 548 cm-1, and 417 cm-1 due to the M - Se stretching and intrinsic stretching vibrations, respectively. The optical bandgap of polycationic selenide lies in the visible light region (2.36 eV). The SEM images showed that PCS has a spherical shape with an average crystallite size of 29.23 nm calculated from XRD data using Scherer's equation. The PCS has a point of zero charge (PZC) at pH 7. The efficiency of synthesized PCS photocatalyst was confirmed in terms of its activity towards Eosin (EY) and Crystal violet (CV) dyes mineralization. The photocatalytic degradation for EY and CV dyes at optimum conditions was 99.47% and 99.31% and followed second order reactions kinetics with 1.4314 and 0.551 rate constant, respectively. The polynomial quadratic model is the best-fitted response surface methodology (RSM) model having a maximum desirability factors value and significant terms, with R2 (0.9994) and adj R2 values (1.0).


Assuntos
Luz Solar , Purificação da Água , Águas Residuárias , Corantes/química , Têxteis , Catálise
6.
Int J Biol Macromol ; 235: 123591, 2023 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-36801223

RESUMO

Due to the rapid race of industrialization natural assets like fresh water has been deteriorated causing lethal effects in living organisms. In the current study robust and sustainable composite of in-situ antimony nanoarchitectonics in chitosan/synthesized carboxymethyl chitosan matrix were synthesized. To improve solubility, metal adsorption and water decontamination, chitosan was modified into carboxymethyl chitosan and the modification was confirmed through various characterization techniques. The characteristic bands in the FTIR spectrum confirm substitution of carboxymethyl group in the chitosan. This was further illustrated that the characteristic proton peaks of CMCh observed at δ = 4.097 to 4.192 ppm, suggesting O-carboxy methylation of chitosan by 1H NMR. The second order derivative of potentiometric analysis confirmed 0.83 degree of substitution. The antimony (Sb) loaded modified chitosan were confirmed by FTIR and XRD analysis. The potential effectiveness of chitosan matrix was determined and compared toward reductive removal of the Rhodamine b dye. Rhodamine b mitigation is following first order kinetics with R2 value of 0.9832 and 0.969 with a constant rate of 0.0977 and 0.2534 ml/min for Sb loaded chitosan and carboxymethyl chitosan respectively. The Sb/CMCh-CFP enables us to achieve 98.5 % mitigation efficiency within 10 min. The CMCh-CFP chelating substrate was found stable and efficient even after 4th batches of cycles with <4 % decrease in efficiency. The in-situ synthesized material was found tailored composite, in terms of dyes remediation, reusability and biocompatibility as compared to chitosan.


Assuntos
Quitosana , Recuperação e Remediação Ambiental , Quitosana/química , Antimônio , Solubilidade , Cobre/química , Prótons , Adsorção
7.
Pak J Med Sci ; 38(4Part-II): 822-825, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35634624

RESUMO

Objectives: To document improvement in quality of life in patients with Hepatitis-C related cirrhosis after successful eradication of the virus. Methods: In this observational cohort study conducted at Fatima Memorial Hospital from September 2015 to July 2017, patients with HCV were assessed for improvement in quality of life by using FACIT-F questionnaire. We compared the Quality of life (QOL) score before the start of treatment with DAAs and after achieving SVR12 in various aspects of quality of life including physical, emotional, functional and social well-being. Results: A total of 71 patients, 52 (73%) were CTP class A, 18 (25%) in B and one (1.4%) in C. The mean score of QOL before AVT was 23.93±7.04 and after achieving SVR it was 36.83±6.36 (P-value <0.001). In the subcategories, score of functional wellbeing, physical well-being and social wellbeing were significantly improved except emotional wellbeing scores. All scores improved across the spectrum of patients in the CTP class A and B. There was only one patient in the CTP-C class. Conclusion: Chronic HCV infection complicated by cirrhosis causes a significant decline in quality of life. There was a marked improvement in the functional, social and physical health of the patients after eradication of Hepatitis-C with anti-viral therapy except emotional health of the individuals.

8.
Chemosphere ; 289: 133121, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34871610

RESUMO

The release of dyes-loaded wastewater from various industries is a major threat to human beings due to their health hazard effects. Ternary ferrites-based visible light photocatalyst Fe2Zn0.5Cu0.5 O4-CM (CZF-CM) was formed via the co-precipitation method. These prepared ternary ferrites nanoparticles Fe2Zn0.5Cu0.5O4 (CZF-NPs) and photocatalyst (CZF-CM) were analyzed using different spectroscopic techniques. The average crystallite size of CZF-NPs was calculated from XRD data using Scherer's equation and found to be 12 nm. The elemental composition of the synthesized ternary ferrites nanoparticles (CZF-NPs) was defined by the EDX images. The morphology of CZF-CM photocatalyst is spherical, having a smooth surface and average microspheres size of 810 µm based on SEM micrographs. The photocatalyst has bandgap of 2.57 eV, which lies in the visible range of the electromagnetic spectrum derived by extrapolating Tauc's plot. Photocatalyst CZF-CM showed 94% degradation efficiency for Rhodamine B (RB) dye at optimized conditions of initial dye concentration, catalyst dosage, pH and sunlight irradiation contact time as 40 ppm, 0.7 g, pH 8 and 125 min, respectively. Maximum degradation (96%) of methyl orange (MO) dye occurred at pH 6, at similar optimized conditions as the RB dye. The binary ferrites photocatalyst Fe2CuO4-CM (CF-CM) and Fe2ZnO4-CM (ZF-CM) of the selected metals showed lesser photocatalytic efficiency than ternary ferrites. An artificial neural network in addition to the response surface methodology was used for the optimization process. The artificial neural network is highly in agreement with the experimental results obtained for the selected dyes. The corresponding predicted response for each data set from ANOVA showed high R2, R2adj, and R2pred values for the proposed model. It also indicates that contributing parameters in the model are significant due to having very high F-values and low p-values. It is concluded that the synthesized photocatalysts are considered an efficient entrant for the decolorization of industrial wastewater.


Assuntos
Descontaminação , Águas Residuárias , Catálise , Corantes , Humanos , Luz
9.
PLoS One ; 16(8): e0255189, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34415906

RESUMO

BACKGROUND & AIM: Hepatitis B and C infections are global issues that are associated with a massive financial burden in developing countries where vertical transmission is the major mode and remains high. This cross-sectional study was designed to investigate the seroepidemiology and associated risk factors of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections among 375 pregnant women attending antenatal care health facilities at Bacha Khan Medical Complex (BKMC) Shahmansoor and District Head Quarter (DHQ) Hospital Swabi, Khyber Pakhtunkhwa, Pakistan. METHODOLOGY: From a total of 375 pregnant women selected using systematic random sampling from both hospitals, 10 ml of blood samples were collected and alienated serum was examined for indicators identification through the Immuno-Chromatographic Test (ICT) and 3rd Generation Enzyme-Linked Immunosorbent Assay (ELISA). A pre-structured questionnaire was used to collect the socio-demographic data and possible risk factors. The data was analyzed via SPSS 23.0 statistical software. A chi-square analysis was performed to determine the association between variables. P-value < 0.05 was set statistically significant. RESULTS: The overall frequency of HBV and HCV among 375 pregnant women involved in the study was 3.7% and 2.1% respectively. None of the pregnant women were co-infected with HBV and HCV. Dental extraction (P = 0.001) and blood transfusion (P = 0.0005) were significantly allied with HBV infection while surgical procedure (P = 0.0001) was significantly associated with HCV infection. Moreover the sociodemographic characteristics: residential status (P = 0.017) and educational level (P = 0.048) were found significant risk factors of HBsAg and maternal age (P = 0.033) of anti-HCV, respectively. CONCLUSION & RECOMMENDATION: HBV and HCV infections are intermediary endemic in the study area. A higher prevalence of HBV was detected among pregnant mothers with a history of dental extraction, history of blood transfusion, resident to the urban area and low educational level. The age and surgical procedures were the potential risk factors found significantly associated with HCV positivity among pregnant mothers in our setup. Future negotiations to control vertical transmission should include routine antenatal screening for these infections early in pregnancy and the requirement of efficient preventive tools including the birth dose of the hepatitis B vaccine in combination with hepatitis B immune globulins to the neonate.


Assuntos
Hepatite B/epidemiologia , Hepatite C/epidemiologia , Hospitais , Gestantes , Estudos Soroepidemiológicos , Adulto , Feminino , Humanos , Paquistão/epidemiologia , Gravidez , Prevalência , Fatores de Risco , Adulto Jovem
10.
Pak J Med Sci ; 36(5): 1117-1132, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32704299

RESUMO

Approximately one half of patients develop ascites within 10 years of diagnosis of compensated cirrhosis. It is a poor prognostic indicator, with only 50% surviving beyond two years. Mortality worsens significantly to 20% to 50% at one year if the ascites becomes refractory to medical therapy. Pakistan has one of the highest prevalence of viral hepatitis in the world and patients with ascites secondary to liver cirrhosis make a major percentage of both inpatient and outpatient burden. Studies indicate that over 80% of patients admitted with ascites have liver cirrhosis as the cause. This expert opinion suggests proper assessment of patients with ascites in the presence of underlying cirrhosis. This expert opinion includes appropriate diagnosis and management of uncomplicated ascites, refractory ascites and complicated ascites (including spontaneous bacterial peritonitis (SBP) ascites, hepatorenal syndrome (HRS) and hyponatremia. The purpose behind this expert opinion is to help consultants, postgraduate trainees, medical officers and primary care physicians optimally manage their patients with cirrhosis and ascites in a resource constrained setting as is often encountered in a developing country like Pakistan.

12.
J Pak Med Assoc ; 65(5): 532-41, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-26028389

RESUMO

Gastroesophageal reflux disease (GERD) is the most common acid-related disorder encountered during clinical practice in Pakistan and is associated with significant impairment of health-related quality of life. A number of guidelines and recommendations for the diagnosis and management of GERD have been published in different countries, but a Pakistani accepted directive by the standards of evidence-based medicine is still lacking. Our aim was to create an understanding of the natural history and presentations of reflux disease; evaluating possible treatment options available for the patients with complex and uncomplicated reflux ailments with the development of current and up to date evidence based endorsement, relevant to the needs of Pakistani health care providers in order to treat oesophageal manifestations of GERD. In order to make such guidelines, a comprehensive literature search was conducted with pertinent evidence reviewed, and quality of relevant data assessed. The resultant conclusions were based on the best available evidence and expert opinion of the authors of technical review panel.


Assuntos
Antiácidos/uso terapêutico , Antiulcerosos/uso terapêutico , Fundoplicatura , Refluxo Gastroesofágico/terapia , Inibidores da Bomba de Prótons/uso terapêutico , Comportamento de Redução do Risco , Adenocarcinoma/diagnóstico , Adenocarcinoma/etiologia , Sulfato de Bário , Esôfago de Barrett/diagnóstico , Esôfago de Barrett/etiologia , Gerenciamento Clínico , Neoplasias Esofágicas/diagnóstico , Neoplasias Esofágicas/etiologia , Monitoramento do pH Esofágico , Esofagoscopia , Medicina Baseada em Evidências , Refluxo Gastroesofágico/complicações , Refluxo Gastroesofágico/diagnóstico , Humanos , Paquistão
13.
J Coll Physicians Surg Pak ; 24(9): 640-4, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25233967

RESUMO

OBJECTIVE: To assess the utility of liver function tests (LFTs) for early recognition and prediction of severity of Dengue fever in hospitalized patients. STUDY DESIGN: An analytical study. PLACE AND DURATION OF STUDY: Services Institute of Medical Science and Fatima Memorial Hospital, Lahore, from September - December 2010. METHODOLOGY: Admitted cases of Dengue fever were divided into 3 groups; mild, moderate and severe increases in aminotransferases. Elevation in LFTs was co-related with good or bad outcome i.e. (survival or complication free stay) or (death or complications). RESULTS were analyzed in SPSS version 18. RESULTS: Out of the 353 patients with mean age of 37.12 ± 15.45 years, 245 (69.4%) were males and 108 (30.6%) were females. Seventy five patients (21.2%) had mild elevation of aminotransferases (2 fold increases), 265 patients (75.1%) had moderate increases (3 to 4 fold) and 13 (3.7%) had severe (> 4 fold increase). ALT was statistically higher in patients with septicemia, hepatic and renal failure (p-value ² 0.05). AST was higher in almost all complications. Prolonged hospital stay was associated with raised LFTs and greater complications and mortality. AST was found to be twice as much raised as ALT. CONCLUSION: AST and ALT were statistically higher in patients with worse outcome thus can lead to early recognition of high risk cases.


Assuntos
Dengue/diagnóstico , Testes de Função Hepática/métodos , Fígado/enzimologia , Índice de Gravidade de Doença , Transaminases/sangue , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Alanina Transaminase/sangue , Aspartato Aminotransferases/sangue , Criança , Pré-Escolar , Dengue/complicações , Dengue/epidemiologia , Feminino , Humanos , Tempo de Internação/estatística & dados numéricos , Fígado/fisiopatologia , Masculino , Pessoa de Meia-Idade , Paquistão/epidemiologia , Adulto Jovem
14.
Liver Int ; 31 Suppl 2: 61-80, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21651703

RESUMO

BACKGROUND: The hepatitis C pandemic has been systematically studied and characterized in North America and Europe, but this important public health problem has not received equivalent attention in other regions. AIM: The objective of this systematic review was to characterize hepatitis C virus (HCV) epidemiology in selected countries of Asia, Australia and Egypt, i.e. in a geographical area inhabited by over 40% of the global population. METHODOLOGY: Data references were identified through indexed journals and non-indexed sources. In this work, 7770 articles were reviewed and 690 were selected based on their relevance. RESULTS: We estimated that 49.3-64.0 million adults in Asia, Australia and Egypt are anti-HCV positive. China alone has more HCV infections than all of Europe or the Americas. While most countries had prevalence rates from 1 to 2% we documented several with relatively high prevalence rates, including Egypt (15%), Pakistan (4.7%) and Taiwan (4.4%). Nosocomial infection, blood transfusion (before screening) and injection drug use were identified as common risk factors in the region. Genotype 1 was common in Australia, China, Taiwan and other countries in North Asia, while genotype 6 was found in Vietnam and other Southeast Asian countries. In India and Pakistan genotype 3 was predominant, while genotype 4 was found in Middle Eastern countries such as Egypt, Saudi Arabia and Syria. CONCLUSION: We recommend implementation of surveillance systems to guide effective public health policy that may lead to the eventual curtailment of the spread of this pandemic infection.


Assuntos
Hepatite C/epidemiologia , Pandemias , Ásia/epidemiologia , Austrália/epidemiologia , Egito/epidemiologia , Genótipo , Hepacivirus/genética , Hepatite C/diagnóstico , Hepatite C/prevenção & controle , Hepatite C/terapia , Hepatite C/transmissão , Humanos , Prevalência , Medição de Risco , Fatores de Risco , Fatores de Tempo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA