Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 155
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
J Environ Manage ; 354: 120228, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38377746

RESUMEN

The effective reduction of hazardous organic pollutants in wastewater is a pressing global concern, necessitating the development of advanced treatment technologies. Pollutants such as nitrophenols and dyes, which pose significant risks to both human and aquatic health, making their reduction particularly crucial. Despite the existence of various methods to eliminate these pollutants, they are not without limitations. The utilization of nanomaterials as catalysts for chemical reduction exhibits a promising alternative owing to their distinguished catalytic activity and substantial surface area. For catalytically reducing the pollutants NaBH4 has been utilized as a useful source for it because it reduces the pollutants quiet efficiently and it also releases hydrogen gas as well which can be used as a source of energy. This paper provides a comprehensive review of recent research on different types of nanomaterials that function as catalysts to reduce organic pollutants and also generating hydrogen from NaBH4 methanolysis while also evaluating the positive and negative aspects of nanocatalyst. Additionally, this paper examines the features effecting the process and the mechanism of catalysis. The comparison of different catalysts is based on size of catalyst, reaction time, rate of reaction, hydrogen generation rate, activation energy, and durability. The information obtained from this paper can be used to steer the development of new catalysts for reducing organic pollutants and generation hydrogen by NaBH4 methanolysis.


Asunto(s)
Contaminantes Ambientales , Contaminantes Químicos del Agua , Purificación del Agua , Humanos , Aguas Residuales , Purificación del Agua/métodos , Catálisis , Hidrógeno , Contaminantes Químicos del Agua/análisis
2.
Anim Biotechnol ; 34(5): 1807-1814, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-35593671

RESUMEN

Rotaviruses are rising as zoonotic viruses worldwide, causing the lethal dehydrating diarrhea in children, piglets, and other livestock of economic importance. A simple, swift, cost-effective, highly specific, and sensitive antigen-capture enzyme-linked immunosorbent assay (AC-ELISA) was developed for detection of porcine rotavirus-A (PoRVA) by employing rabbit (capture antibody) and murine polyclonal antibodies (detector antibody) produced against VP6 of PoRVA (RVA/Pig-tc/CHN/TM-a/2009/G9P23). Reactivity of the both polyclonal antibodies was confirmed by using an indirect ELISA, western-blot analysis and indirect fluorescence assay against rVP6 protein and PoRVA. The detection limit of AC-ELISA was found 50 ng/ml of PoRVA protein. The relative sensitivity and specificity of this in-house AC-ELISA were evaluated for detection of PoRVA from 295 porcine diarrhea samples, and results were compared with that of RT-PCR and TaqMan RT-qPCR. The relative sensitivity and specificity of AC-ELISA compared with those of TaqMan RT-qPCR were found as 94.4 and 99.2%, respectively, with the strong agreement (κ -0.58) between these two techniques. Furthermore, AC-ELISA could not detect any cross-reactivity with porcine epidemic diarrhea virus, transmissible gastro-enteritis virus, pseudo rabies virus and porcine circovirus-2. This in-house AC-ELISA efficiently detected PoRVA from clinical samples, which suggests that this technique can be used for large-scale surveillance and timely detection of rotavirus infection in the porcine farms.


In this study, we used a Chinese porcine rotavirus-A (PoRVA) strain containing the I5, a dominant VP6-genotype in pigs, for production of VP6 (most conserved) protein based polyclonal antibodies (pAb) in rabbits (as capture Ab) and mouse (as detector Ab) for development of simple, cost effective, highly specific and sensitive AC-ELISA for detection of PoRVA. Furthermore, there is no any previous published report on application of rabbit and mouse pAb against VP6 for developing an AC-ELISA against PoRVA.


Asunto(s)
Infecciones por Rotavirus , Rotavirus , Enfermedades de los Porcinos , Animales , Porcinos , Conejos , Ratones , Infecciones por Rotavirus/diagnóstico , Infecciones por Rotavirus/veterinaria , Diarrea , Ensayo de Inmunoadsorción Enzimática/veterinaria , Anticuerpos Antivirales , Sensibilidad y Especificidad , Enfermedades de los Porcinos/diagnóstico
3.
Pak J Med Sci ; 39(4): 1101-1107, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37492326

RESUMEN

Objective: To evaluate the various temporary transvenous pacemaker (TPM) access sites, its indications, procedural complications, and outcomes of patients. Methods: This prospective study conducted in a tertiary care hospital of Peshawar, included 100 patients, who underwent TPM for any reasons, via the trans jugular, subclavian, or trans-femoral route. The duration of the study was from October 1st, 2021 to March 31st, 2022. The demographic, procedure -related complications, causes of complete heart block and in hospital outcomes were recorded. Results: Of the 100 patients who underwent temporary transvenous pacing, 56%were males and 44% were females, with an age range of 46-80 years. In majority of the patients, (N =54) internal jugular vein was used as the venous access site followed by the subclavian vein. (N=24). Coronary artery disease was prevalent in 42% of the patients. 50% had complete AV block, 19% had symptomatic second-degree block, and 10% had sinus nodal diseases. Seventy three percent of the patients needed TPM implantation on an emergency basis, which is statistically significant (p=0.009). Almost 40% of the patient ultimately underwent a permanent pacemaker. Out of 100 patients, 16 patients expired. The major procedure related complications were bleeding 16% overall at the puncture site and 14.8% in the internal jugular group. Other complications were local infection 13% at the insertion site followed by hemopericardium 3%, in the internal jugular group. Conclusion: Atrioventricular block is the commonest indication for temporary pacing in our study. The average time the TPM remained in place was significantly higher in the trans jugular approach group along with a higher complication rate in this group.

4.
Pak J Med Sci ; 39(6): 1657-1660, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37936769

RESUMEN

Objective: The objective of this study was to determine the diagnostic value of stress perfusion CMR for the detection of coronary artery disease. Methods: The was a retrospective cross sectional study in which 43 subjects were included from Cardiac MRI unit in the Hayatabad Medical Complex, Peshawar for study from 1st April 2020 to 30th November 2020. All the subjects who had been referred for stress perfusion CMR with suspected CAD were included in the study. Cardiac MRI both at rest and with adenosine stress perfusion was performed which was followed by invasive coronary angiography. Result: A total of 43 patients were enrolled for the detection or exclusion CAD who underwent stress perfusion CMRI and invasive coronary artery angiography. The study revealed strong and statistically significant association between positive stress perfusion CMR and positive coronary angiogram vs negative stress perfusion CMR and negative coronary angiogram (p= value 0.0001). Conclusions: Stress perfusion CMRI can be considered as a first line, relatively safe, noninvasive test with significant accuracy to diagnose coronary artery disease in patients with suspected CAD without subjecting these patients to invasive coronary angiogram.

5.
Angew Chem Int Ed Engl ; 61(5): e202113207, 2022 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-34918438

RESUMEN

Hybrid lead halide perovskite solar cells (PSCs) have emerged as potential competitors to silicon-based solar cells with an unprecedented increase in power conversion efficiency (PCE), nearing the breakthrough point toward commercialization. However, for hole-transporting materials, it is generally acknowledged that complex structures often create issues such as increased costs and hazardous substances in the synthetic schemes, when translated from the laboratory to manufacture on a large scale. Here, we present cyclobutane-based hole-selective materials synthesized using simple and green-chemistry inspired protocols in order to reduce costs and adverse environmental impact. A series of novel semiconductors with molecularly engineered side arms were successfully applied in perovskite solar cells. V1366-based PSCs feature impressive efficiency of 21 %, along with long-term operational stability under atmospheric environment. Most importantly, we also fabricated perovskite solar modules exhibiting a record efficiency over 19 % with an active area of 30.24 cm2 .

6.
Microb Pathog ; 129: 118-124, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30738177

RESUMEN

For detection and isolation of Salmonella enterica, 650 meat and tissue samples were processed using Rappaport-Vassiliadis Enrichment broth and Salmonella Chromogenic agar followed by confirmation through specific antisera and polymerase chain reaction (PCR) targeting their Specific Serovar Genomic Regions (SSGRS). Isolates were tested for 15 antibiotics (CRO, AMX, GEN, STR, TET, CHL, CLR, LVX, OFX, GAT, CIP, SXT, AMP, LIN and AZM) according to the disc diffusion method and antimicrobial resistant genes (tet(A), tet(B), tet(C), strA/strB, aadA, aac(3)IV), aadB, sul1, sul2 and sul3, blaCMY-2, blaTEM and blaSHV) using PCR. The overall prevalence of Salmonella enterica was 12%, being higher in markets (15%) as compared to poultry farms (37.2%). The MPN of all positive meat and tissue samples was found 3.6 MPN/gram (0.17-18). A total of 234 isolates were obtained, serovar Typimurium (139) and Enteridits (95) were the most prevalent. Antimicrobial resistance patterns were different in different serovars according to origin of Salmonella isolates. The overall isolates were highly resistant for LIN (93.1%, 218/234) followed by AMX (80%, 187/234), AMP (74.3%, 174/234), TET (64.5%, 151/234) and STR (64.5%, 151/234). Overall, the most common ARG was blaTEM (76%, 178/234), followed by blaSHV (71.7%, 168/234), tet(A) (64%, 151/234) and tet(B) (64%, 150/234), while the least ARG was aadB (7.2%, 17/234). Both Typimurium and Enteridits were tested in the Balb/C mice for pathogenicity. Both Typimurium and Enteridits were found to cause successful colonization, 100% morbidity but Enteriditis were found to cause 33% mortality.


Asunto(s)
Farmacorresistencia Bacteriana , Enfermedades de las Aves de Corral/microbiología , Productos Avícolas/microbiología , Salmonelosis Animal/microbiología , Salmonella enteritidis/aislamiento & purificación , Salmonella typhimurium/aislamiento & purificación , Animales , Antibacterianos/farmacología , Técnicas Bacteriológicas , Femenino , Genes Bacterianos , Ratones Endogámicos BALB C , Modelos Animales , Reacción en Cadena de la Polimerasa , Aves de Corral , Prevalencia , Salmonelosis Animal/epidemiología , Salmonella enteritidis/efectos de los fármacos , Salmonella enteritidis/genética , Salmonella typhimurium/efectos de los fármacos , Salmonella typhimurium/genética , Análisis de Supervivencia
7.
Microb Pathog ; 115: 93-99, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29273508

RESUMEN

Shiga toxin Escherichia coli (STEC) O157:H7 is an important zoonotic food borne pathogen causing gastroenteritis that may lead to life threatening hemorragic colitis (HC) and hemorrhagic uremic syndrome (HUS). 325 meat and tissue samples were tested for enumeration of O157:H7 strains using most probable number (MPN)-PCR targeting their specific genes flicH7 and rfbO157 followed by isolation, sereotyping and pathogenicity testing. The overall prevalence of O157:H7 was 41.3% (134/325) along the production and supply chain of pork (PSCP), being higher in supply chain (59%, 118/200) as compared to pig farms (12.8%, 16/125). Along the PSCP, the highest prevalence was found in slaughter houses (86.25%, 69/80) followed by wet- (53.3%, 32/60) and super-markets (28.3%, 17/60). The MPN values ranged from 3 to 1100 MPN/g in overall positive samples, being higher in slaughter houses followed by wet and super markets. Except from intestine and meat samples of slaughter house, the MPN was found higher in summer as compared to winter samples. Eight STEC O157:H7 isolated from meat and liver samples were tested in Balb/C mice for pathogenicity. After development of clinical signs and symptoms, 50-83.3% mortality was produced in the infected mice. Histopathological investigations revealed visible necrosis of intestinal epithelial cells, shedding of cellular debris in the intestine, while in the kidney, necrosis of renal cortical portion of tubular epithelial cells was observed. STEC O157:H7 is prevalent along PSCP around Hubei of China in different proportions being alarmingly higher in supply chain and markets which is a matter of concern for public health.


Asunto(s)
Infecciones por Escherichia coli/epidemiología , Infecciones por Escherichia coli/microbiología , Escherichia coli O157/aislamiento & purificación , Escherichia coli O157/patogenicidad , Microbiología de Alimentos , Toxinas Shiga/genética , Escherichia coli Shiga-Toxigénica/aislamiento & purificación , Escherichia coli Shiga-Toxigénica/patogenicidad , Mataderos , Animales , Animales Domésticos , Proteínas Bacterianas/genética , China/epidemiología , ADN Bacteriano , Modelos Animales de Enfermedad , Células Epiteliales/microbiología , Células Epiteliales/patología , Escherichia coli O157/clasificación , Escherichia coli O157/genética , Proteínas de Escherichia coli/genética , Femenino , Flagelina/genética , Contaminación de Alimentos/análisis , Intestinos/microbiología , Intestinos/patología , Hígado/microbiología , Ratones , Ratones Endogámicos BALB C , Técnicas de Diagnóstico Molecular , Mortalidad , Necrosis/microbiología , Necrosis/patología , Reacción en Cadena de la Polimerasa , Prevalencia , Carne Roja/microbiología , Serotipificación , Escherichia coli Shiga-Toxigénica/clasificación , Escherichia coli Shiga-Toxigénica/genética , Porcinos , Virulencia , Factores de Virulencia/genética
8.
Biochem Biophys Res Commun ; 490(3): 889-894, 2017 08 26.
Artículo en Inglés | MEDLINE | ID: mdl-28648600

RESUMEN

We present here the biosynthesis of AgNps from the aqueous extract of H. thebaica fruit, and monitored through UV-Vis spectrophotometer. The functional group were characterized through ATR-FTIR spectroscopy, the particle size, morphologies and elemental composition of the nanoparticles were investigated by using TEM, FESEM and EDS respectively. The anti-proliferation activity of the synthesized AgNps was carried out using MTT assay on human prostate (PC3), breast (MCF7) and liver (HepG2) cancer cell lines. The anti-proliferation assay showed that the AgNps were able to inhibit the proliferation of the cancer cell lines in a dose depending manner. The effect was found more pronounced on prostate (IC50 2.6 mg/mL) followed by breast (IC50 4.8 mg/mL) and then liver cancer cell lines (IC50 6.8 mg/mL). The prepared AgNps were found to inhibit 99% growth of both E. coli and S. aureus after 24 h of incubation. The nanoparticles were used for the degradation of 4-nitrophenol (4-NP) and Congo red dyes (CR), which efficiently degrade CR, but make complex formation with 4-NP. Therefore, the AgNps synthesized from the aqueous fruit extract of H. thebaica have potential application in pharmacology and waste water treatment.


Asunto(s)
Antibacterianos/química , Antineoplásicos/química , Arecaceae/química , Contaminantes Ambientales/aislamiento & purificación , Nanopartículas del Metal/química , Plata/química , Antibacterianos/farmacología , Antineoplásicos/farmacología , Línea Celular Tumoral , Colorantes/química , Colorantes/aislamiento & purificación , Rojo Congo/química , Rojo Congo/aislamiento & purificación , Contaminantes Ambientales/química , Escherichia coli/metabolismo , Infecciones por Escherichia coli/tratamiento farmacológico , Frutas/química , Humanos , Nanopartículas del Metal/ultraestructura , Neoplasias/tratamiento farmacológico , Nitrofenoles/química , Nitrofenoles/aislamiento & purificación , Oxidación-Reducción , Extractos Vegetales/química , Plata/farmacología , Infecciones Estafilocócicas/tratamiento farmacológico , Staphylococcus aureus/efectos de los fármacos
9.
Microb Pathog ; 112: 254-258, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28963012

RESUMEN

The study project was designed to determine the effects of Clostridium perfringens type D infection on hematological and biochemical parameters in goats. Purposive blood samples were collected from 6 healthy and 12 diseased goats positive for C. perfringens infection. Neither the animals nor their mother were vaccinated against Clostridium perfringens from whom samples were obtained. Study was carried out in two different topographic areas; hilly (district Swat) and plain (district Mardan) of Khyber Pakhtunkhwa, Pakistan but nonsignificant (P > 0.05) statistical difference was recorded between the prevalence of Clostridium perfringens infected goats. Mean erythrocytes count (RBC) and hemoglobin level decreased significantly (P < 0.05) while the white blood cells (WBC) increased significantly (P < 0.05) in diseased animals compared to the healthy animals. However non-significant differences (P > 0.05) were observed in packet cell volume (PCV) and platelets count in healthy and diseased animals. According to biochemical analysis, a significant increase (P < 0.05) in liver enzymes, total bilirubin, serum creatinine, blood urea and glucose was recorded in diseased goats. . The results demonstrated that fluctuation in most of the mean hematological values remained within the normal range however the mean liver enzymes, total bilirubin, serum creatinine, blood urea and glucose levels gone beyond the normal levels which demonstrated severe damages to liver and kidneys.


Asunto(s)
Biomarcadores/sangre , Infecciones por Clostridium/sangre , Infecciones por Clostridium/veterinaria , Clostridium perfringens/patogenicidad , Enfermedades de las Cabras/microbiología , Animales , Animales Domésticos , Bilirrubina , Glucemia , Infecciones por Clostridium/epidemiología , Infecciones por Clostridium/microbiología , Clostridium perfringens/clasificación , Clostridium perfringens/genética , Clostridium perfringens/aislamiento & purificación , Creatinina/sangre , ADN Bacteriano/análisis , Eritrocitos , Heces/microbiología , Femenino , Enfermedades de las Cabras/diagnóstico , Enfermedades de las Cabras/epidemiología , Cabras , Humanos , Riñón , Recuento de Leucocitos , Hígado/enzimología , Masculino , Pakistán/epidemiología , Prevalencia , Factores de Riesgo , Factores Sexuales , Encuestas y Cuestionarios , Urea/sangre
10.
Mikrochim Acta ; 185(1): 24, 2017 12 06.
Artículo en Inglés | MEDLINE | ID: mdl-29594448

RESUMEN

The authors describe a sensor based on the deposition of the binary oxide SnO2-Mn3O4 between copper electrodes fixed on a glass substrate. The impedance of the sensor is shown to strongly depend on relative humidity (RH) and mechanical pressure. A silicone adhesive was added to the binary oxide nanomaterials and investigated with respect to its effect on the sensing performance. The impedance of the material decreases by a factor of 54.7 with increasing RH in the range of 10-90% in pristine SnO2-Mn3O4 nanorods, but 29.6 times in SnO2-Mn3O4 nanocomposites. Capacitance increases 390 times in pristine SnO2-Mn3O4 and 26.6 times in SnO2-Mn3O4 silicone nanocomposite at 100 Hz on going from 10 to 90% RH. Similarly, the impedance of the sensor also depends on mechanical pressure. The impedance of the material decreases by 80% on applying a mechanical pressure of 11.0 kN·m-2, while capacitance increases by 70% at the same pressure. Graphical abstract A multimodal sensor was fabricated using SnO2-Mn3O4 mixed oxide and its nanocomposite with silicon adhesive. The impedance of the material decreases while capacitance increases much more with increase in relative humidity and applying a mechanical pressure in SnO2-Mn3O4 mixed oxide as compared to SnO2-Mn3O4 nanocomposite.

11.
RSC Adv ; 14(1): 211-221, 2024 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-38173605

RESUMEN

A hydrogel membrane was prepared using activated carbon and sodium dodecyl sulphate modified montmorillonite clay incorporated into sodium alginate polymer. The activated carbon was prepared from a locally available susbine plant. The physiochemical characteristics of the synthesized hydrogel membrane were investigated using FTIR, SEM, EDX, and TGA techniques. The performance of the membrane was evaluated as an adsorbent by methyl red adsorption from water. The adsorption behavior of the hydrogel membrane was investigated under varying conditions of pH (2-10), membrane dose (0.0025-0.015 mg g-1), equilibrium adsorption time (30-360 minutes), solution temperature (25-45 °C) and dye concentration (100-500 mg L-1). The maximum adsorption capacity of the hydrogel membrane was 248.13 mg g-1. The kinetics of methyl red adsorption on hydrogel membrane best followed the pseudo-second order (PSO). The equilibrium adsorption results suggested that it obeyed the Freundlich isotherm very closely (R2 = 0.994). The thermodynamics of methyl red adsorption on the hydrogel membrane revealed that the adsorption was spontaneous (ΔS° = 16.15 kJ K-1 mol-1), favorable (ΔG° = -3.51 kJ mol-1), and endothermic (ΔH° = -1.48 kJ mol-1) in nature. These investigations suggested that the fabricated hydrogel membrane could be suitably used for methyl red adsorption from the solution.

12.
Int J Biol Macromol ; 268(Pt 1): 131558, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38614166

RESUMEN

Water contamination caused by toxic compounds has emerged as one of the most severe challenges worldwide. Biomass-based nanocomposites offer a sustainable and renewable alternative to conventional materials. In this study, a nanocomposite of mint and cellulose acetate (Mint-CA) was prepared and employed as a supportive material for Cu nanoparticles (CuNPs) and Ag nanoparticles (AgNPs). The selectivity of CuNPs@mint-CA and AgNPs@mint-CA was assessed by comparing their performance in the reduction reaction of various dyes solutions. AgNPs@mint-CA exhibited superior catalytic performance, with a removal of 95.2 % for methyl orange (MO) compared to 68 % with CuNPs@mint-CA. The absorption spectra of MO exhibited a distinct peak at 464 nm. The reduction reaction of MO by AgNPs@mint-CA followed pseudo-first-order-kinetic with a rate constant of k = 0.0063 min-1 (R2 = 0.928). The highest removal of MO was achieved under the following conditions: a catalyst weight of 40 mg, an initial MO concentration of 0.07 mM, the addition of 0.5 mL of 0.1 M NaBH4, and a temperature of 25 °C. Furthermore, the AgNPs@mint-CA catalyst exhibited exceptional reducibility even after five use cycles, highlighting its potential for efficiently removing MO.


Asunto(s)
Compuestos Azo , Celulosa , Nanopartículas del Metal , Compuestos Azo/química , Celulosa/química , Celulosa/análogos & derivados , Nanopartículas del Metal/química , Catálisis , Plata/química , Nanocompuestos/química , Mentha/química , Oxidación-Reducción , Contaminantes Químicos del Agua/química , Cinética , Cobre/química
13.
Int J Biol Macromol ; 257(Pt 1): 128544, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38061525

RESUMEN

This work reports silver nanoparticles (AgNPs) supported on biopolymer carboxymethyl cellulose beads (Ag-CMC) serves as an efficient catalyst in the reduction process of p-nitrophenol (p-NP) and methyl orange (MO). For Ag-CMC synthesis, first CMC beads were prepared by crosslinking the CMC solution in aluminium nitrate solution and then the CMC beads were introduced into AgNO3 solution to adsorb Ag ions. Field emission scanning electron microscopy (FE-SEM) analysis suggests the uniform distribution of Ag nanoparticles on the CMC beads. The X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis revealed the metallic and fcc planes of AgNPs, respectively, in the Ag-CMC catalyst. The Ag-CMC catalyst exhibits remarkable reduction activity for the p-NP and MO dyes with the highest rate constant (kapp) of a chemical reaction is 0.519 and 0.697 min-1, respectively. Comparative reduction studies of Ag-CMC with CMC, Fe-CMC and Co-CMC disclosed that Ag-CMC containing AgNPs is an important factore in reducing the organic pollutants like p-NP and MO dyes. During the recyclability tests, the Ag-CMC also maintained high reduction activity, which suggests that CMC protects the AgNPs from leaching during dye reduction reactions.


Asunto(s)
Nanopartículas del Metal , Plata , Plata/química , Nanopartículas del Metal/química , Carboximetilcelulosa de Sodio , Biopolímeros , Colorantes/química
14.
Chemosphere ; 355: 141743, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38513958

RESUMEN

Silver oxide doped iron oxide (Ag2O-Fe2O3) nanocatalyst was prepared and coated on cotton cloth (CC) as well as wrapped in sodium alginate (Alg) hydrogel. Ag2O-Fe2O3 coated CC (Ag2O-Fe2O3/CC) and Ag2O-Fe2O3 wrapped Alg (Ag2O-Fe2O3/Alg) were utilized as catalysts in reduction reaction of 4-nitrophenol (4-NP), congo red (CR), methylene blue (MB) and potassium ferricyanide (K3[Fe(CN)6]). Ag2O-Fe2O3/CC and Ag2O-Fe2O3/Alg were found to be effective and selective catalyst for the reaction of K3[Fe(CN)6]. Further amount of catalyst, K3[Fe(CN)6] quantity, amount of NaBH4, stability of catalyst and recyclability were optimized for the reaction of K3[Fe(CN)6] reduction. Ag2O-Fe2O3/Alg and Ag2O-Fe2O3/CC were appeared to be the stable catalysts by maintaining high activity during recyclability tests showing highest reaction rate constants (kapp) of 0.3472 and 0.5629 min-1, correspondingly. However, Ag2O-Fe2O3/CC can be easily recovered as compared to Ag2O-Fe2O3/Alg by simply removing from the reaction which is the main advantage of Ag2O-Fe2O3/CC. Moreover, Ag2O-Fe2O3/Alg and Ag2O-Fe2O3/CC were also examined in real samples and found useful for K3[Fe(CN)6] reduction involving real samples. The Ag2O-Fe2O3/CC nanocatalyst is a cost and time saving material for economical reduction of K3[Fe(CN)6] and environmental safety.


Asunto(s)
Alginatos , Compuestos Férricos , Ferricianuros , Nanocompuestos , Óxidos , Compuestos de Plata
15.
Z Naturforsch C J Biosci ; 79(5-6): 137-148, 2024 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-38820053

RESUMEN

Antimicrobial resistance (AMR) has emerged as a significant and pressing public health concern, posing serious challenges to effectively preventing and treating persistent diseases. Despite various efforts made in recent years to address this problem, the global trends of AMR continue to escalate without any indication of decline. As AMR is well-known for antibiotics, developing new materials such as metal containing compounds with different mechanisms of action is crucial to effectively address this challenge. Copper, silver, and chitosan in various forms have demonstrated significant biological activities and hold promise for applications in medicine and biotechnology. Exploring the biological properties of these nanoparticles is essential for innovative therapeutic approaches in treating bacterial and fungal infections, cancer, and other diseases. To this end, the present study aimed to synthesize silver@copper oxide (Ag@CuO) nanoparticles and its chitosan nanocomposite (Chi-Ag@CuO) to investigate their antimicrobial efficacy. Various established spectroscopic and microscopic methods were employed for characterization purposes, encompassing scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Subsequently, the antimicrobial activity of the nanoparticles was assessed through MIC (minimum inhibitory concentration), MBC (minimum bactericidal concentration), and well-disk diffusion assays against Pseudomonas aeruginosa, Acinetobacter baumannii Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans. The size of the CuO-NPs, Ag@CuO, and Chi-Ag@CuO NPs was found to be 70-120 nm with a spherical shape and an almost uniform distribution. The nanocomposites were found to possess a minimum inhibitory concentration (MIC) of 5 µg/mL and a minimum bactericidal concentration (MBC) of 250 µg/mL. Moreover, these nanocomposites generated varying clear inhibition zones, with diameters ranging from a minimum of 9 ± 0.5 mm to a maximum of 25 ± 0.5 mm. Consequently, it is evident that the amalgamation of copper-silver-chitosan nanoparticles has exhibited noteworthy antimicrobial properties in the controlled laboratory environment, surpassing the performance of other types of nanoparticles.


Asunto(s)
Antiinfecciosos , Quitosano , Cobre , Nanopartículas del Metal , Pruebas de Sensibilidad Microbiana , Nanocompuestos , Plata , Quitosano/química , Quitosano/farmacología , Cobre/química , Cobre/farmacología , Nanocompuestos/química , Plata/química , Plata/farmacología , Nanopartículas del Metal/química , Antiinfecciosos/farmacología , Antiinfecciosos/química , Espectroscopía Infrarroja por Transformada de Fourier , Difracción de Rayos X , Antibacterianos/farmacología , Antibacterianos/química , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/crecimiento & desarrollo , Microscopía Electrónica de Rastreo , Bacterias/efectos de los fármacos , Bacterias/crecimiento & desarrollo
16.
Int J Biol Macromol ; 262(Pt 2): 129986, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38360231

RESUMEN

Until now, many efficient catalysts have been reported that are used for the reduction of nitroarenes. However, a catalyst reusability is a challenge that is often faced in practical environment. In this report, we designed a hydrogel composite (CMC-LDH), which act as support and making it possible to address this challenge. In this research work, zinc/aluminum based layered double hydroxides (Zn/Al LDH) have been assembled with carboxymethyl cellulose (CMC) to prepare CMC/LDH hydrogel beads. The CMC/LDH hydrogel beads were prepared by the ionotropic gelation method. For CMC/LDH/Au preparation, the already prepared CMC/LDH beads were kept in gold ion (Au3+) solution, and their subsequent reduction with sodium borohydride (NaBH4). For the characterization of the prepared samples different instrumental techniques, such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy, and scanning electron microscopy (SEM) were adopted. For the catalytic evaluation of CMC/LDH/Au, it was utilized as a catalyst in 4-NP and 4-NA reduction reactions. The continuity of the reaction was monitored by a UV-visible spectrophotometer. Rate constant (kapp) of 0.48474 min-1 and 0.7486 min-1 were obtained for 4-NP and 4-NA reduction, respectively. The hydrogel beads were recycled and reused for up to five successive cycles without significantly changing their catalytic efficiency.


Asunto(s)
Carboximetilcelulosa de Sodio , Nanopartículas del Metal , Compuestos de Zinc , Carboximetilcelulosa de Sodio/química , Oro , Nanopartículas del Metal/química , Hidrogeles/química , Zinc , Compuestos Orgánicos , Hidróxidos/química
17.
Int J Biol Macromol ; 233: 123564, 2023 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-36754261

RESUMEN

In this project, lanthanum oxide doped tin oxide (SnLa2O5) nanomaterial was prepared and characterized morphologically and physiochemically by different techniques. The catalytic performance of SnLa2O5 was assessed toward catalytic reduction of 4-nitrophenol (4-NP), methyl orange (MO), congo red (CR), methylene blue (MB) and potassium ferricyanide (K3[Fe(CN)6]). SnLa2O5 was found to be efficient for K3[Fe(CN)6] in the presence of NaBH4, which reduced in only 8.0 min. SnLa2O5 was further wrapped in carboxymethyl cellulose mixed calcium alginate (CMC-Alg) hydrogel beads because the powder catalyst cannot be simply recovered from reaction media to recycle and use again. SnLa2O5 wrapped CMC-Alg (SnLa2O5/CMC-Alg) was assessed for detail analysis of K3[Fe(CN)6] reduction. The effect of NaBH4, K3[Fe(CN)6] concentration and amount of catalyst was optimized using SnLa2O5/CMC-Alg. The amount of catalyst has positive impact on catalytic reduction of K3[Fe(CN)6]. The kinetic study revealed that K3[Fe(CN)6] reduction by SnLa2O5 and SnLa2O5/CMC-Alg was fast, which completed in 8.0 and 4.0 min with rate constant of 0.4283 min-1 and 0.7461 min-1, respectively. These findings indicated that the developed SnLa2O5/CMC-Alg is best and proficient nanocatalyst for K3[Fe(CN)6] reduction. The efficiency along with cost-effective and simple treatment route of the developed nanocatalyst have prospect to compete and replace the reputable commercial catalysts.


Asunto(s)
Contaminantes Ambientales , Nanocompuestos , Carboximetilcelulosa de Sodio/química , Alginatos/química , Hidrogeles
18.
Polymers (Basel) ; 15(6)2023 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-36987282

RESUMEN

In this work, we have developed novel beads based on carboxymethyl cellulose (CMC) encapsulated copper oxide-titanium oxide (CuO-TiO2) nanocomposite (CMC/CuO-TiO2) via Al+3 cross-linking agent. The developed CMC/CuO-TiO2 beads were applied as a promising catalyst for the catalytic reduction of organic and inorganic contaminants; nitrophenols (NP), methyl orange (MO), eosin yellow (EY) and potassium hexacyanoferrate (K3[Fe(CN)6]) in the presence of reducing agent (NaBH4). CMC/CuO-TiO2 nanocatalyst beads exhibited excellent catalytic activity in the reduction of all selected pollutants (4-NP, 2-NP, 2,6-DNP, MO, EY and K3[Fe(CN)6]). Further, the catalytic activity of beads was optimized toward 4-nitrophenol with varying its concentrations and testing different concentrations of NaBH4. Beads stability, reusability, and loss in catalytic activity were investigated using the recyclability method, in which the CMC/CuO-TiO2 nanocomposite beads were tested several times for the reduction of 4-NP. As a result, the designed CMC/CuO-TiO2 nanocomposite beads are strong, stable, and their catalytic activity has been proven.

19.
Materials (Basel) ; 16(21)2023 Oct 31.
Artículo en Inglés | MEDLINE | ID: mdl-37959575

RESUMEN

Silver oxide-doped tin oxide (SnAg2O3) nanoparticles were synthesized and different spectroscopic techniques were used to structurally identify SnAg2O3 nanoparticles. The reduction of 4-nitrophenol (4-NP), congo red (CR), methylene blue (MB), and methyl orange (MO) was studied using SnAg2O3 as a catalyst. Only 1.0 min was required to reduce 95% MO; thus, SnAg2O3 was found to be effective with a rate constant of 3.0412 min-1. Being a powder, SnAg2O3 is difficult to recover and recycle multiple times. For this reason, SnAg2O3 was coated on adhesive tape (AT) to make it recyclable for large-scale usage. SnAg2O3@AT catalyst was assessed toward MO reduction under various conditions. The amount of SnAg2O3@AT, NaBH4, and MO was optimized for best possible reduction conditions. The catalyst had a positive effect since it speed up the reduction of MO by adding more SnAg2O3@AT and NaBH4 as well as lowering the MO concentration. SnAg2O3@AT totally reduced MO (98%) in 3.0 min with a rate constant of 1.3669 min-1. These findings confirmed that SnAg2O3@AT is an effective and useful catalyst for MO reduction that can even be utilized on a large scale for industrial purposes.

20.
ACS Omega ; 8(42): 38849-38859, 2023 Oct 24.
Artículo en Inglés | MEDLINE | ID: mdl-37901518

RESUMEN

In the present study, a biosorbent was prepared through the radiation-induced graft polymerization (RIGP) technique by using a glycidyl methacrylate (GMA) monomer. Functionalized bamboo materials were used for grafting. The grafting percentage (G %) of GMA on bamboo fibers was assessed based on the optimization of the absorbed dose and concentration of the monomer. The chemical modification of the polymerized product into the sulfonated form of the grafted biopolymer was carried out by using sodium sulfite solution. The modification of the biopolymer at various stages was analyzed by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) techniques. By performing scanning electron microscopy (SEM), the morphological changes of the prepared biopolymer were analyzed. The temperature stability of the synthesized material was assessed by the thermogravimetric analysis (TGA) technique. The prepared sulfonated biosorbent was used in the batch adsorption study for the uptake of copper. We examined a variety of variables, including pH, adsorbent dosage, and time. The adsorption kinetics were studied using pseudo-first-order (PFO) and pseudo-second-order (PSO) models. Adsorption isotherms and thermodynamic parameters were also applied to study the adsorption capacity of the biosorbent. The maximum copper adsorption capacity was found to be 198 mg g-1 from the Langmuir isotherm. Copper adsorption followed PSO kinetics (R2 = 0.999). This inexpensive and eco-friendly biosorbent removed 96% of copper ions from the solution.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA