Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 38
Filtrar
Mais filtros

País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Molecules ; 28(3)2023 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-36770591

RESUMO

Reduced graphene oxide nanosheets decorated with ZnS and ZnS-Ag nanoparticles are successfully prepared via a facile one-step chemical approach consisting of reducing the metal precursors on a rGO surface. Prepared rGO-ZnS nanocomposite is employed as an adsorbent material against two model dyes: malachite green (MG) and ethyl violet (EV). The adsorptive behavior of the nanocomposite was tuned by monitoring some parameters, such as the time of contact between the dye and the adsorbent, and the adsorbent dose. Experimental data were also simulated with kinetic models to evaluate the adsorption behavior, and the results confirmed that the adsorption of both dyes followed a pseudo 2nd order kinetic mode. Moreover, the adsorbent was also regenerated in a suitable media for both dyes (HCl for MG and ethanol for EV), without any significant loss in removal efficiency. Ag doped rGO-ZnS nanocomposite was also utilized as a photocatalyst for the degradation of the selected organic contaminant, resorcinol. The complete degradation of the phenolic compound was achieved after 60 min with 200 mg of rGO-ZnS-Ag nanocomposite under natural sunlight irradiation. The photocatalytic activity was studied considering some parameters, such as the initial phenol concentration, the photocatalyst loading, and the pH of the solution. The degradation kinetics of resorcinol was carefully studied and found to follow a linear Langmuir-Hinshelwood model. An additional advantage of rGO-ZnS and rGO-ZnS-Ag nanocomposites was antibacterial activity against Gram-negative bacterium, E. coli, and the results confirmed the significant performance of the nanocomposites in destroying harmful pathogens.


Assuntos
Grafite , Nanopartículas Metálicas , Nanocompostos , Purificação da Água , Prata/farmacologia , Prata/química , Nanopartículas Metálicas/química , Adsorção , Escherichia coli , Grafite/farmacologia , Grafite/química , Antibacterianos/farmacologia , Antibacterianos/química , Fenóis , Corantes , Nanocompostos/química , Resorcinóis
2.
Molecules ; 27(19)2022 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-36234973

RESUMO

In this manuscript, the application of cetyltrimethylammonium bromide (CTAB) and cetylpyridinium chloride (CPC) for the removal of Naphthol Green B (NGB) as a synthetic effluent has been studied. The solubilization of NGB by a single and mixed micellar system using Triton X-100 (TX-100) as a nonionic surfactant has been performed to establish both the extent of the partitioning (kx) of NGB and ultimately their respective Gibbs free energies ΔGp as well. An applied methodology, micellar-enhanced ultrafiltration (MEUF), has also been studied in different micellar media of cationic surfactants by variation in some selective parameters, such as the concentration of surfactant, electrolyte, pressure, pH, and RPM to obtain optimum conditions. The results have been analyzed by a UV/visible double beam spectrophotometer. ΔGp was found to be -39.65 kJ/mol and -47.94 kJ/mol by CTAB and CPC, respectively, in the presence of a nonionic surfactant. The maximum value of Gibbs free energy (ΔGp) of the partition was obtained by CPC. The values of the rejection coefficient (R%) and permeate flux (J) are also calculated. A maximum removal of 99.77% and 98.53% by CTAB and CPC, respectively, was obtained. It has been observed that both of the surfactants are strong candidates for NGB removal.


Assuntos
Micelas , Ultrafiltração , Cetrimônio , Cetilpiridínio , Eletrólitos , Compostos Férricos , Naftalenossulfonatos , Octoxinol , Tensoativos , Ultrafiltração/métodos
3.
Molecules ; 27(23)2022 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-36500426

RESUMO

Micellar-enhanced ultrafiltration (MEUF), being a separation technique, was used to remove cobalt metal ion (Co2+) from their aqueous solutions in an application to reduce the toxicity level from industrial effluents using a micellar solution of anionic and cationic surfactants. The metal ions were first adsorbed by using anionic surfactants, i.e., sodium dodecyl sulfate (SDS) and sodium oleate (SO). The calculations for partition (Kx) and binding constants (Kb) and their respective free energy of partition and binding (ΔGp and ΔGb kJmol-1) helped significantly to find out the extent of binding or interaction of Co2+ with the surfactant and ΔGp and ΔGb were found to be -29.50 and -19.38 kJmol-1 for SDS and -23.95 and -12.67 kJmol-1 in the case of SO. MEUF work was also performed to find out the optimal conditions to remove metal pollutants from the aqueous system. For the said purpose, various factors and concentrations effect were studied, such as the concentration of the surfactant, concentration of the electrolyte (NaCl), transmembrane pressure, RPM, and pH. The efficiency of this process was checked by calculating various parameters, such as rejection percentage (R%) and permeate flux (J). A maximum rejection of 99.95% with SDS and 99.99% with SO was attained.


Assuntos
Cobalto , Micelas , Ultrafiltração/métodos , Dodecilsulfato de Sódio , Tensoativos , Íons
4.
J Environ Manage ; 230: 199-211, 2019 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-30286349

RESUMO

Here in, we presented a facile one-step method for the synthesis of Graphene oxide-silver (GO-Ag) nanocomposite and its applications as a sorbent for the elimination of some toxic pollutants from aqueous medium, as an efficient catalyst in the individual as well as simultaneous reduction reactions of multiple compounds, and as an antibacterial agent for the destruction of some harmful microorganisms existent in wastewater. GO was prepared using a modified Hummers method and Ag nanoparticles were integrated on GO sheets by chemical reduction of Ag+ ions on the surfaces of GO sheets. The composition and morphology of the nanocomposite was extensively characterized with elemental dispersive X-ray analysis (EDX), Fourier transform infra-red (FT-IR) spectroscopy, transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and thermal gravimetric analysis (TGA). The GO-Ag nanocomposite demonstrated remarkable adsorption capacities and recyclability for malachite green (MG) and ethyl violet (EV) dyes. Various experimental parameters affecting adsorptive behavior of nanocomposite like temperature, pH, time of contact between dye and adsorbent, and adsorbent dose were evaluated thoroughly. Experimental data was simulated with different adsorption isotherms and kinetic models to evaluate adsorption behavior of both dyes and results confirmed the adsorption of both the dyes to be followed by pseudo 2nd order kinetic model and Langmuir adsorption model. Moreover, adsorbent was regenerated in suitable media for both dyes without any loss in removal efficiency. The catalytic performance for the 2-nitroaniline (2-NA) reduction was investigated in detail. Most importantly, the prepared nanocomposite was found to have potential to adsorb multiple pollutants all together as well as to catalyze the simultaneous reduction of a mixture of dyes (MG, MO, and EV) and 2-NA. An additional advantage of the GO-Ag nanocomposite was its antibacterial activity acquired to the presence of Ag nanoparticles. Two bacterial strains (Gram-negative bacterium, E. coli and the Gram-positive bacterium, S. aureus) were used to test antibacterial activity of composite and the results confirmed the remarkable performance of the nanocomposite in destroying harmful pathogens.


Assuntos
Antibacterianos/química , Grafite/química , Nanopartículas Metálicas/química , Óxidos/química , Compostos de Prata/química , Água/química , Adsorção , Antibacterianos/farmacologia , Catálise , Descontaminação , Escherichia coli/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Óxidos/síntese química , Compostos de Prata/síntese química , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos
5.
Biol Chem ; 398(7): 737-750, 2017 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-27926476

RESUMO

In the past, divergent results have been reported based on different methods and conditions used for enzymatic activity measurements of cytochrome c oxidase (CytOx). Here, we analyze in detail and show comparable and reproducible polarographic activity measurements of ATP-dependent inhibition of CytOx kinetics in intact and non-intact rat heart mitochondria and mitoplasts. We found that this mechanism is always present in isolated rat heart mitochondria and mitoplasts; however, it is measurable only at high ATP/ADP ratios using optimal protein concentrations. In the kinetics assay, measurement of this mechanism is independent of presence or absence of Tween-20 and the composition of measuring buffer. Furthermore, the effect of atractyloside on intact rat heart mitochondria confirms that (i) ATP inhibition occurs under uncoupled conditions [in the presence of carbonly cyanide m-chlorophenyl hydrazone (CCCP)] when the classical respiratory control is absent and (ii) high ATP/ADP ratios in the matrix as well as in the cytosolic space are required for full ATP inhibition of CytOx. Additionally, ATP inhibition measured in intact mitochondria extends in the presence of oligomycin, thus indicating further that the problem to measure the inhibitory effect of ATP on CytOx is apparently due to the lack of very high ATP/ADP ratios in isolated mitochondria.


Assuntos
Difosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Trifosfato de Adenosina/farmacologia , Complexo IV da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Mitocôndrias Cardíacas/enzimologia , Animais , Cinética , Mitocôndrias Cardíacas/metabolismo , Ratos
6.
Cell Biol Int ; 41(2): 155-162, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27888557

RESUMO

To evaluate the effect of regulatory T cells (Tregs) on the inflammation resulting from lipopolysaccharide (LPS) challenge in prenatal brain tissue, Tregs isolated from pregnant mice were transferred into model mice, and the expression levels of fork head family transcription factor (Foxp3), interleukin-6 (IL-6), CD68 (a marker of microglia), and toll-like receptor 4 (TLR-4) were assessed in the fetal brain tissue. Foxp3, IL-6, and TLR-4 expression were detected by polymerase chain reaction and Western blot; CD68 expression level was detected using immunochemical analysis. Foxp3, IL-6, TLR-4, and CD68 expressions in fetal brain were significantly induced by maternal LPS administration, and the increased expression levels were markedly reduced by adoptive transfer of Tregs. Maternal LPS exposure significantly induced inflammation in perinatal brain tissue, and Tregs negatively regulated this LPS-induced inflammation.


Assuntos
Encéfalo/efeitos dos fármacos , Lipopolissacarídeos/toxicidade , Linfócitos T Reguladores/imunologia , Transferência Adotiva , Animais , Antígenos CD/genética , Antígenos CD/metabolismo , Antígenos de Diferenciação Mielomonocítica/genética , Antígenos de Diferenciação Mielomonocítica/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Modelos Animais de Doenças , Feminino , Feto/efeitos dos fármacos , Feto/metabolismo , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismo , Inflamação/prevenção & controle , Interleucina-6/genética , Interleucina-6/metabolismo , Camundongos , Microglia/metabolismo , Gravidez , Nascimento Prematuro , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/metabolismo , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/metabolismo , Regulação para Cima/efeitos dos fármacos
7.
J Environ Manage ; 197: 631-641, 2017 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-28432888

RESUMO

In this work, microgels based on tris(2-aminoethyl) amine (TAEA) and glycerol diglycidyl ether (GDE) via simple microemulsion polymerization was prepared as p(TAEA-co-GDE) microgels were used as adsorbent for removal of dichromate (Cr (VI)) and arsenate (As (V)) ions from different aqueous environments. The p(TAEA-co-GDE) microgels were demonstrated very efficient adsorption capacity for Cr (VI), and As (V) that are 164.98 mg/g, and 123.64 mg/g from distilled (DI) water, respectively. The effect of the medium pH on the adsorption capacity of p(TAEA-co-GDE) microgels for Cr (VI) and As (V) ions were investigated. The maximum adsorption capacity was obtained at pH 4.0 for both ions with maximum adsorbed amounts of 160.62, and 98.72 mg/g, respectively. In addition, the microgels were also shown moderate adsorption capacity for Cr (VI) and As (V) from other water sources; tap water with 115.18 mg/g and 82.86 mg/g, sea water with 64.24 mg/g and 46.88 mg/g and creek water with 73.52 mg/g and 59.33 mg/g, respectively. Moreover, the increase in adsorbent dose from 0.025 to 0.125 g enhanced % adsorption of Cr (VI) from 54.13 to 98.03, and As (V) from % 26.72-98.70, respectively. For the adsorption process Langmuir and Freundlich adsorption isotherms were applied and found that Langmuir adsorption isotherm with R2 value of 0.99 for both the metal ions are suitable. Moreover, the experimental adsorption capacities of Cr (VI) and As (V) were found very close to the theoretical values calculated from Langmuir adsorption isotherm. More importantly, the microgels were made magnetic responsive to recover them easily from adsorption medium for reuse studies by applying external magnetic field with little decrease in adsorption capacity. Additionally, reusability of p(TAEA-co-GDE) microgels was also evaluated for adsorption of Cr (VI) and As (V) from DI water.


Assuntos
Arseniatos , Poluentes Químicos da Água , Adsorção , Aminas , Cromo , Glicerol , Concentração de Íons de Hidrogênio , Íons
8.
J Environ Sci (China) ; 37: 100-9, 2015 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-26574093

RESUMO

Various compositions of cobalt and sulfur co-doped titania nano-photocatalyst are synthesized via sol-gel method. A number of techniques including X-ray diffraction (XRD), ultraviolet-visible (UV-Vis), Rutherford backscattering spectrometry (RBS), thermal gravimetric analysis (TGA), Raman, N2 sorption, electron microscopy are used to examine composition, crystalline phase, morphology, distribution of dopants, surface area and optical properties of synthesized materials. The synthesized materials consisted of quasispherical nanoparticles of anatase phase exhibiting a high surface area and homogeneous distribution of dopants. Cobalt and sulfur co-doped titania demonstrated remarkable structural and optical properties leading to an efficient photocatalytic activity for degradation of dyes and phenol under visible light irradiations. Moreover, the effect of dye concentration, catalyst dose and pH on photodegradation behavior of environmental pollutants and recyclability of the catalyst is also examined to optimize the activity of nano-photocatalyst and gain a better understanding of the process.


Assuntos
Cobalto/química , Corantes/química , Nanopartículas/química , Fenol/química , Fotólise , Enxofre/química , Titânio/química , Catálise , Poluentes Ambientais/química , Concentração de Íons de Hidrogênio
9.
World Neurosurg X ; 23: 100345, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38511157

RESUMO

Background: The Entrapped Temporal Horn (ETH) is characterized by localized enlargement of the temporal horn of the lateral ventricle of the brain. This study aimed to investigate the factors, development, prognosis, and effective treatment. Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, a systematic search was conducted in major research databases. The inclusion criteria included patients of all ages with TTH diagnosis in cohort studies, case series, and case reports. Results: Our study included 160 patients and 49 studies. The major causes of TTH were neoplastic lesions (42.3%), infections (22.3%), and cystic disease (13.08%). Of these cases, 71 were unrelated to cranial surgery, while 89 were unrelated to prior surgeries. Headache was the most common symptom (41.91%), followed by seizures (13.20%), drowsiness (12.50%) and memory loss (11.00%). Surgery was not required in 17 patients. Fenestration of the trapped temporal horn was performed in 24 patients, while VP/VA shunt surgeries were performed in the majority (57 patients) owing to favorable outcomes, lower revision rates, and extensive experience. However, TTH recurred in six of the 21 patients who underwent endoscopic ventriculocisternostomy. Tumors were the main cause, and isolated headache was the most frequent symptom. Ventriculoperitoneal shunts (VPS) are preferred because of their positive outcomes, lower revision rates, and wider expertise. Tumors near the trigonal area pose a higher risk. Conclusion: Although TTH remains a rare condition, VPS continues to be the most widely preferred procedure among surgeons.

10.
RSC Adv ; 13(41): 28785-28797, 2023 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-37790101

RESUMO

Hybrid composites of molybdenum disulfide (MoS2), graphene nanoplatelets (GNPs) and polyaniline (PANI)/polypyrrole (PPy) have been synthesized as cost-effective electrode materials for supercapacitors. We have produced MoS2 from molybdenum dithiocarbamate by a melt method in an inert environment and then used a liquid exfoliation method to form its composite with graphene nanoplatelets (GNPs) and polymers (PANI and PPy). The MoS2 melt/GNP ratio in the resultant composites was 1 : 3 and the polymer was 10% by wt. of the original composite. XRD (X-ray diffraction analysis) confirmed the formation of MoS2 and SEM (scanning electron microscopy) revealed the morphology of the synthesized materials. The electrochemical charge storage performance of the synthesized composite materials was assessed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge (GCCD) measurements. Resultant composites showed enhanced electrochemical performances (specific capacitance = 236.23 F g-1, energy density = 64.31 W h kg-1 and power density = 3858.42 W kg-1 for MoS2 melt 5 mPP at a current density of 0.57 A g-1 and had 91.87% capacitance retention after 10 000 charge-discharge cycles) as compared to the produced MoS2; thus, they can be utilized as electrode materials for supercapacitors.

11.
RSC Adv ; 13(28): 19508-19529, 2023 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-37388146

RESUMO

It is universally accepted that the financial advancement of a state is essentially dependent upon the energy sector as it is essential in the growth, development, and improvement of the farming, mechanical, and defense sectors. A dependable source of energy is expected to enhance society's expectation of everyday comforts. Modern industrial advancement, which is indispensable for any nation, relies upon electricity. The principal explanation behind the energy emergency is rapidly increasing the use of hydrocarbon resources. Thus, the use of renewable resources is essential to overcome this dilemma. The consumption of hydrocarbon fuels and their discharge has destructive consequences on our surroundings. Third-generation photovoltaic (solar) cells are latest encouraging option in solar cells. Currently, dye-sensitized solar cells (DSSC) utilize organic (natural and synthetic) dye and inorganic (ruthenium) as a sensitizer. The nature of this dye combined with different variables has brought about a change in its use. Natural dyes are a feasible alternative in comparison to expensive and rare ruthenium dye owing to their low cast, easy utility, abundant supply of resources, and no environmental threat. In this review, the dyes generally utilized in DSSC are discussed. The DSSC criteria and components are explained, and the progress in inorganic and natural dyes is monitored. Scientists involved in this emerging technology will benefit from this examination.

12.
Bioengineering (Basel) ; 10(1)2023 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-36671672

RESUMO

Pharmacological strategies to lower the viral load among patients suffering from severe diseases were researched in great detail during the SARS-CoV-2 outbreak. The viral protease Mpro (3CLpro) is necessary for viral replication and is among the main therapeutic targets proposed, thus far. To stop the pandemic from spreading, researchers are working to find more effective Mpro inhibitors against SARS-CoV-2. The 33.8 kDa Mpro protease of SARS-CoV-2, being a nonhuman homologue, has the possibility of being utilized as a therapeutic target against coronaviruses. To develop drug-like compounds capable of preventing the replication of SARS-main CoV-2's protease (Mpro), a computer-aided drug design (CADD) approach is extremely viable. Using MOE, structure-based virtual screening (SBVS) of in-house and commercial databases was carried out using SARS-CoV-2 proteins. The most promising hits obtained during virtual screening (VS) were put through molecular docking with the help of MOE. The virtual screening yielded 3/5 hits (in-house database) and 56/66 hits (commercial databases). Finally, 3/5 hits (in-house database), 3/5 hits (ZINC database), and 2/7 hits (ChemBridge database) were chosen as potent lead compounds using various scaffolds due to their considerable binding affinity with Mpro protein. The outcomes of SBVS were then validated using an analysis based on molecular dynamics simulation (MDS). The complexes' stability was tested using MDS and post-MDS. The most promising candidates were found to exhibit a high capacity for fitting into the protein-binding pocket and interacting with the catalytic dyad. At least one of the scaffolds selected will possibly prove useful for future research. However, further scientific confirmation in the form of preclinical and clinical research is required before implementation.

13.
Chemosphere ; 339: 139583, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37480955

RESUMO

A solvothermal method was used to synthesize the mesoporous TiO2, (1-3w %) Cu-doped mesoporous TiO2 membrane with the help of a bioreactor. To understand the physicochemical composition of all synthesized nanomaterials, the structure, morphology and crystallinity of the materials were studied using X-ray diffractometer (XRD), Field emission scanning electron microscopy (FESEM), Fourier transform-infrared (FTIR), Energy dispersive X-ray spectroscopy (EDS) and cyclic voltammetry (CV). Under artificial light source (500 W mercury bulb) irradiations, the nano catalysts' catalytic effectiveness was examined for the azo dyes, namely Congo red. Cu-doping causes a shift in the light absorption of mTiO2 from the ultraviolet to the visible region. The 3w% Cu-doped mTiO2 photocatalyst exhibits lower band gap energy (2.6eV) than TiO2 which is 3.2 eV to efficiently utilize solar energy. As a result, the light absorption was shifted towards the visible spectrum. The recommended mTiO2 and (1, 2, 3) w% Cu-doped mTiO2 photocatalysts were used to photodegrade Congo red and methylene blue. For the degradation of CR, the mTiO2 photocatalyst exhibited 61% and 3w% Cu-doped mTiO2 demonstrated 99% photocatalytic performance after 50 min. A variety of scavengers were also utilized to distinguish the active species by catching the radicals and holes created during the process of photocatalytic degradation. CV indicates the presence of Cu2+ and Cu1+ in Cu-doped mTiO2. Oxygen vacancies and the electronegative surface of Cu1+ seem to perform the photocatalytic reduction of CR.


Assuntos
Vermelho Congo , Luz , Titânio/química , Corantes , Catálise
14.
Bioelectrochemistry ; 149: 108285, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36240548

RESUMO

This study is designed to investigate the interaction of phenylpiperidine derivative drug paroxetine, which is an effective serotonin reuptake inhibitor and biomolecules through electrochemical, fluorescence spectroscopy, and molecular docking methods. The interaction between paroxetine and biomolecules was investigated by differential pulse voltammetry according to the decrease in deoxyguanosine anodic oxidation signal of double-stranded calf thymus DNA. Fluorescence spectroscopy studies were performed by titrating paroxetine against double-stranded calf thymus DNA solution at four different temperatures. The fluorescent results showed that paroxetine had a great affinity to bind with double-stranded calf thymus DNA. Interaction studies demonstrate that paroxetine binds to double-stranded calf thymus DNA via intercalation binding mode, and the binding constant values ​​were calculated as 7.24 × 104 M-1 and 1.52 × 104 M-1 at 25 °C, based on voltammetric and spectroscopic results, respectively. Moreover, with the aim of elucidating the interaction mechanism between paroxetine and double-stranded calf thymus DNA, electrochemical and fluorescence spectroscopy studies along with molecular docking analysis were made.


Assuntos
DNA , Paroxetina , Antidepressivos/farmacologia , Dicroísmo Circular , DNA/química , Simulação de Acoplamento Molecular , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Termodinâmica
15.
ACS Macro Lett ; 12(10): 1345-1350, 2023 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-37722025

RESUMO

Although graphite derivatives, such as graphene, graphene oxide, and reduced graphene oxide, have been widely used as lubricating oil additives to reduce friction and wear, their synthesis either proceeds with complicated procedures in low yield, suffering from high cost, or involves the utilization of highly corrosive chemicals, raising safety and environmental concerns. Therefore, the direct use of pristine graphite as a lubricating oil additive is indispensable for practical tribological applications. However, the realization of this idea has been seriously hampered by the incompatibility of graphite with lubricating base oils. In this work, we report a rational strategy to directly disperse graphite in base oils in the form of oleogels assisted by pyrene functionalized telechelic polymers under mild condition. The resulting oleogels exhibit long-time colloidal stability for more than one year, wherein the graphite has been exfoliated to in situ form graphene through π-π interactions with the pyrene-containing telechelics. Moreover, compared with the base oil, the graphite-based oleogels are found to exhibit remarkable reductions in friction and wear by up to 52% and 97%, respectively. Significantly, such tribological performances are comparable to those of exfoliated graphite derivatives. Taken collectively, directly using pristine graphite as a lubricating oil additive with superior tribological properties represents a revolutionary approach to create low-cost, green, and high-performance lubricants just based on pristine layered materials without involving any pre-exfoliations.

16.
Gels ; 9(1)2023 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-36661830

RESUMO

Herein, polymeric cryogels containing poly(N-isopropylacrylamide) were synthesized by cryo-polymerization at subzero temperature. The synthesized cryogels were loaded with silver and palladium nanoparticles by the chemical reduction method at room temperature using the reducing agent NaBH4. Moreover, for comparison with cryogels, pure poly(N-isopropylacrylamide) hydrogel and its silver hybrid were also prepared by the conventional method at room temperature. The chemical structure and functional group analysis of the pure cryogels was confirmed by Fourier transform infrared spectroscopy. The synthesis of hybrid cryogels was confirmed by the X-ray diffraction technique and energy dispersive X-ray. The pore size and surface morphology of the pure cryogels, their respective hybrid cryogels and of conventional hydrogels were studied by using the scanning electron microscopy technique. The hybrid cryogels were successfully used as a catalyst for the degradation of methyl orange dye. The degradation performance of the hybrid cryogels was much better than its counterpart hybrid hydrogel for methyl orange dye. The effect of temperature and amount of catalyst on catalytic performance was studied by UV-visible spectroscopy. The reduction follows pseudo-first-order reaction kinetics. In addition, the antibacterial activities of these cryogels were evaluated against Gram-positive bacteria (Staphylococcus aureus, ATCC: 2593) and Gram-negative bacteria (Escherichia coli, ATCC: 25922). Both hybrid cryogels have shown much better antibacterial activity for these two strains of bacteria compared to pure cryogels. The results indicate that these cryogels are potential candidates for water purification systems as well as biomedical applications.

17.
Cureus ; 15(8): e43584, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37719589

RESUMO

We describe a rare case of concurrent eosinophilic granulomatosis with polyangiitis and mixed connective tissue disease in a 27-year-old man who presented with pulmonary, renal, cardiac, and skin manifestations. We confirmed the diagnosis based on clinical, histopathological, and serological criteria. We treated the patient with corticosteroids, methotrexate, cyclophosphamide, and hydroxychloroquine, achieving early remission. The coexistence of both conditions in the same patient is extremely rare and has only been reported in a few cases worldwide. We also review the literature on these two rare autoimmune diseases' coexistence, pathogenesis, diagnosis, and management. Our case emphasizes recognizing overlapping autoimmune conditions in patients with complex clinical features and employing a comprehensive diagnostic approach and tailored treatment strategies. Further research is needed to understand these patients' epidemiology, prognosis, and optimal therapy. Early diagnosis and aggressive immunosuppression are crucial for achieving remission and preventing organ damage. We also identified the knowledge gaps and research needs in this field.

18.
J Ayub Med Coll Abbottabad ; 34(Suppl 1)(3): S730-S732, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36414604

RESUMO

A fibroepithelial polyp is a benign polypoidal lesion of mesodermal origin. It can present in any area of the body with an epithelial surface. These are relatively more common in skin and genitourinary tract and has been reported very rarely in head and neck region. We report here a rare presentation of fibroepithelial polyp in sinonasal cavity presenting with the symptoms of unilateral nasal obstruction. The patient underwent endoscopic surgical excision and recovered completely. In patients with unilateral sinonasal growing masses fibroepithelial polyp should be considered as one of the possible diagnoses. Sinonasal fibroepithelial polyps have good prognosis after being treated surgically.


Assuntos
Neoplasias Cutâneas , Humanos , Pele , Cabeça , Pescoço , Peso Molecular
19.
RSC Adv ; 12(51): 33215-33228, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36425212

RESUMO

Herein, we report poly(N-isopropylacrylamide/2-acrylamido-2-methylpropane sulfonic acid) microgel fabricated with silver nanoparticles. The identification of copolymerization and functional groups in the bare microgel and those fabricated with silver nanoparticles was examined by Fourier transform infrared spectroscopy. The pH and temperature sensitivity of microgels was studied using dynamic light scattering. Thermogravimetric analysis was carried out to study the thermal stability. X-Ray diffraction patterns indicated the amorphous nature of bare microgel and crystalline nature of those containing silver nanoparticles. A bathochromic shift was found in the surface plasmon resonance of silver nanoparticles present in microgel with increase in pH of the medium. Moreover, the microgel containing silver nanoparticles served as an effective catalyst for reducing the toxic nitroaromatic pollutants and carcinogenic dyes. The microgel containing silver nanoparticles also showed good capability to serve as biosensor for the detection of hydrogen peroxide.

20.
Bioelectrochemistry ; 146: 108135, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35468353

RESUMO

This study examines the interaction between pyrimidine nucleoside analogue azacytidine, an anti-leukemic drug, and DNA by employing electrochemical, UV-vis spectroscopy, fluorescence spectroscopy and molecular docking techniques. In the electrochemical technique, azacytidine and dsDNA interaction was investigated in two different ways: (1) in solution and (2) with a biosensor using differential pulse voltammetry (DPV) at a glassy carbon electrode. The interaction between azacytidine and dsDNA at increasing interaction times was investigated in line with the changes in adenine and guanine oxidation signals. In addition, interaction studies of polyguanine-azacytidine and polyadenine-azacytidine were performed with DPV. The binding constant values were calculated as 2.420 × 104 M-1 and 3.266 × 104 M-1 at 25 °C using UV and fluorescence spectroscopy, respectively. In conclusion, based on electrochemical and spectroscopic methods as well as molecular docking studies, it was predicted that azacytidine can bind to dsDNA via groove binding.


Assuntos
Azacitidina , Técnicas Biossensoriais , Técnicas Biossensoriais/métodos , DNA/química , Técnicas Eletroquímicas/métodos , Eletrodos , Simulação de Acoplamento Molecular , Análise Espectral
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA