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1.
J Environ Manage ; 348: 119363, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37931434

RESUMO

Worldwide, environmental concerns about MPs pollution have increased. Microplastic contamination that pollutes the ocean is mostly caused by terrestrial transfer from close proximity locations. A study of MPs pollution near coastal locations becomes necessary to address the MPs transit, fate, and mitigation. In the current study MPs pollution in the surface water and sediment of the Mahanadi River estuary was assessed during Pre-MS and MS. The size, shape, and colour of the MPs were determined using a stereomicroscope, and the MPs polymer composition was identified by Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy. The mean concentration of MPs that were potentially discovered in water was 16.6 ± 5.2 and sediments 197.3 ± 5.4 during Pre-MS. In the MS observed mean abundance of MPs was 15.1 ± 5.4 in water and 164.6 ± 76.9 in sediments. The highest abundant size was smaller than 1 mm; the most prevalent shape were fibers followed by film and fragments; black and white was a prominent colour in water and sediments respectively. Polyesters (PEs), polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), polyamide (PA), Polystyrene (PS), and Polycarbonates (PC) were found in the analysis of the chemical composition of MPs in water and sediments samples. The calculated PLI value shows pollution load at category I, with polymer hazard levels at categories III, IV, and V, indicating very high risk. The current research results show that river inflows and fishing-related actions are probably the main causes of MPs pollution.


Assuntos
Microplásticos , Poluentes Químicos da Água , Microplásticos/análise , Microplásticos/química , Plásticos/química , Água/análise , Rios/química , Sedimentos Geológicos , Poluentes Químicos da Água/análise , Monitoramento Ambiental , Polímeros , Índia
2.
J Environ Manage ; 316: 115194, 2022 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-35537267

RESUMO

The oil spill represents one of the most important pollution sources for marine environments, that occurs due to tanker collisions, ship accidents, and platforms. Several techniques are used for treating oil spill disasters including chemical, physical, and biochemical. The use of chemicals, magnetite nanomaterials (MNMs) in particular, is one of the most applied techniques used for oil spill remediation due to their low cost, fast remediation, and reusability. This work aims to synthesize and use new ionic liquids (ILs) for the modification of MNMs surfaces to enhance their performance for crude oil uptake. For that, octadecylamine (OA) was reacted with epichlorohydrin (EH), followed by reaction with either diethylenetriamine (DT), or tetraethylenepentamine (TP) to obtain corresponding amines, OADT, and OATP, respectively. The produced amines were quaternized using acetic acid (AA) forming corresponding ILs, OADT-IL, and OATP-IL. The obtained ILs, OADT-IL, and OATP-IL were applied for modification of magnetite nanomaterials (MNMs) surface to obtain the surface-modified MNMs, DT-MNMs, and TP-MNMs, respectively. The surface-modified MNMs were characterized using different techniques including Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and contact angle. The efficacy of DT-MNMs, and TP-MNMs for heavy crude oil uptake (EMU) was evaluated. Further, the factors affecting on the crude oil uptake including MNMs: heavy crude oil ratio, and contact time were also evaluated. The data exhibited that, the EMU relatively declined as the ratio of DT-MNMs, and TP-MNMs decreased. Even at low MNMs:crude oil ratio (1:50), DT-MNMs, and TP-MNMs displayed EMU 87%, and 90%, respectively, which means 1 g of either DT-MNMs, or TP-MNMs can uptake 45 g, or 43.5 g, respectively. These values are high as compared with other studies that reported the use of MNMs for oil spill cleanup. Furthermore, the data indicated that the EMU increased as the contact time increased, and reached maximum EMU of 98% for both MNMs samples after 10 min.


Assuntos
Líquidos Iônicos , Nanoestruturas , Transportadores de Ânions Orgânicos , Poluição por Petróleo , Petróleo , Aminas , Óxido Ferroso-Férrico , Poluição por Petróleo/análise
3.
Artif Organs ; 45(12): 1501-1512, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34309044

RESUMO

The primary role of bone tissue engineering is to reconcile the damaged bones and facilitate the speedy recovery of the injured bones. However, some of the investigated metallic implants suffer from stress-shielding, palpability, biocompatibility, etc. Consequently, the biodegradable scaffolds fabricated from polymers have gathered much attention from researchers and thus helped the tissue engineering sector by providing many alternative materials whose functionality is similar to that of natural bones. Herein, we present the fabrication and testing of a novel composite, magnesium (Mg)-doped hydroxyapatite (HAp) glazed onto polylactic acid (PLA) scaffolds where polyvinyl alcohol (PVA) used as a binder. For the composite formation, Creality Ender-3 pro High Precision 3D Printer with Shape tool 3D Technology on an FSD machine operated by Catia design software was employed. The composite has been characterized for the crystallinity (XRD), surface functionality (FTIR), morphology (FESEM), biocompatibility (hemolytic and protein absorption), and mechanical properties (stress-strain and maximum compressive strength). The powder XRD analysis confirmed the semicrystalline nature and intact structure of HAp even after doping with Mg, while FTIR studies for the successful formation of Mg-HAp/PVA@PLA composite. The FESEM provided analysis indicated for the 3D porous architecture and well-defined morphology to efficiently transport the nutrients, and the biocompatibility studies are supporting that the composite for blood compatible with the surface being suitable enough for the protein absorption. Finally, the composite's antibacterial activity (against Staphylococcus aureus and Escherichia coli) and the test of mechanical properties supported for the enhanced inhibition of active growth of microorganisms and maximum compressive strength, respectively. Based on the research outcomes of biocompatibility, antibacterial activity, and mechanical resistance, the fabricated Mg-HAp/PVA@PLA composite suits well as a promising biomaterial platform for orthopedic applications by functioning towards the open reduction internal fixation of bone fractures and internal repairs.


Assuntos
Osso e Ossos , Poliésteres/química , Engenharia Tecidual/métodos , Alicerces Teciduais , Durapatita/química , Escherichia coli/efeitos dos fármacos , Hemólise , Humanos , Magnésio/química , Teste de Materiais , Impressão Tridimensional , Staphylococcus aureus/efeitos dos fármacos
4.
Molecules ; 25(23)2020 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-33261115

RESUMO

With an aim to develop more effective and affordable anticancer agents possessing a unique mechanism of action, we designed and synthesized derivatives of spirooxindole-pyrrolidine heterocyclic hybrids in good yields through a one-pot three-component (3+2) cycloaddition strategy. The synthesized compounds were characterized thoroughly for the physicochemical properties by making use of FT-IR, NMR spectroscopy, and mass spectrometry. Further, these compounds have been evaluated for the influence of anticancer activity against HepG2 cells up to 200 µg/mL concentration. The highly active molecular scaffold was tested for the in-depth mechanistic studies, and it was found that the major pathway of cell death is apoptosis which occurs through the induction of reactive oxygen species followed by the involvement of caspases.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Compostos Heterocíclicos/química , Pirrolidinas/química , Compostos de Espiro/química , Apoptose , Proliferação de Células , Reação de Cicloadição , Células Hep G2 , Humanos , Técnicas In Vitro , Estrutura Molecular , Relação Estrutura-Atividade
5.
Molecules ; 25(11)2020 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-32526838

RESUMO

Early diagnosis of bone metastases is crucial to prevent skeletal-related events, and for that, the non-invasive techniques to diagnose bone metastases that make use of image-guided radiopharmaceuticals are being employed as an alternative to traditional biopsies. Hence, in the present work, we tested the efficacy of a gallium-68 (68Ga)-based compound as a radiopharmaceutical agent towards the bone imaging in positron emitting tomography (PET). For that, we prepared, thoroughly characterized, and radiolabeled [68Ga]Ga-NODAGA-pamidronic acid radiopharmaceutical, a 68Ga precursor for PET bone cancer imaging applications. The preparation of NODAGA-pamidronic acid was performed via the N-Hydroxysuccinimide (NHS) ester strategy and was characterized using liquid chromatography-mass spectrometry (LC-MS) and tandem mass spectrometry (MSn). The unreacted NODAGA chelator was separated using the ion-suppression reverse phase-high performance liquid chromatography (RP-HPLC) method, and the freeze-dried NODAGA-pamidronic acid was radiolabeled with 68Ga. The radiolabeling condition was found to be most optimum at a pH ranging from 4 to 4.5 and a temperature of above 60 °C. From previous work, we found that the pamidronic acid itself has a good bone binding affinity. Moreover, from the analysis of the results, the ionic structure of radiolabeled [68Ga]Ga-NODAGA-pamidronic acid has the ability to improve the blood clearance and may exert good renal excretion, enhance the bone-to-background ratio, and consequently the final image quality. This was reflected by both the in vitro bone binding assay and in vivo animal biodistribution presented in this research.


Assuntos
Acetatos/farmacocinética , Osso e Ossos/diagnóstico por imagem , Osso e Ossos/metabolismo , Radioisótopos de Gálio/farmacocinética , Compostos Heterocíclicos com 1 Anel/farmacocinética , Pamidronato/farmacocinética , Tomografia por Emissão de Pósitrons/métodos , Compostos Radiofarmacêuticos/farmacocinética , Acetatos/química , Animais , Cromatografia Líquida de Alta Pressão , Radioisótopos de Gálio/química , Compostos Heterocíclicos com 1 Anel/química , Masculino , Espectrometria de Massas , Pamidronato/química , Compostos Radiofarmacêuticos/química , Ratos , Ratos Sprague-Dawley , Distribuição Tecidual
6.
Bioorg Med Chem ; 27(12): 2487-2498, 2019 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-30853330

RESUMO

A small library of spirooxindole-pyrrolidine hybrids have been synthesized for the first time in an ionic liquid, [bmim]Br in good to excellent yields employing a new class of non-stabilized azomethine ylides derived from isatin and tyrosine, a combination that has been rarely employed for the in situ generation of azomethine ylides using [3+2] cycloaddition strategy. Following the synthesis and characterization of the spirooxindole-pyrrolidine heterocyclic hybrids, they were tested for their anticancer activity as against the changes in the concentrations and time periods with different in vitro cell cultures containing cancer and non-cancer cells, where the results revealed for a potential therapeutic activity. Further analysis for the mechanism of cell death by the cancer cells indicated for the caspase-dependent apoptotic pathway, specifically mediated by caspase-3. Based on these results, it can be demonstrated that the synthesized spirooxindole-pyrrolidine hybrids may serve as one of the better therapeutic agents used for the treatment of malignant tumors.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Indóis/química , Pirrolidinas/química , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Reação de Cicloadição , Humanos , Compostos de Espiro/química , Relação Estrutura-Atividade
7.
Molecules ; 24(21)2019 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-31652778

RESUMO

Novel hexacyclic cage-like hybrid heterocycles have been synthesized in excellent yields employing a relatively less explored non-stabilized azomethine ylides derived from acenaphthenequinone and tyrosine with functionalized dipolarophiles using [3 + 2] cycloaddition strategy. The synthesized hexacyclic cage-like hybrid heterocycles were characterized by spectroscopic analysis. Following the physical characterization, these cage-like hybrid heterocycles were tested for their biological activity by means of different cancer (A549 and Jurkat cells) and non-cancer (BRL-3A and PCS-130) in vitro cell culture systems. The results of the study under tested concentrations (up to 100 µM) indicated that these compounds are not affecting any viability to the cell growth of non-cancer cells, while providing significant anticancer activity against both of the cancer cells. Further analysis of in-depth mechanistic study for the cell death indicated that these compounds are exhibiting late apoptosis or early necrosis pathway to the cells where it is operated by the induction of caspases.


Assuntos
Acenaftenos/química , Antineoplásicos/química , Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Compostos Azo/química , Neoplasias/tratamento farmacológico , Tiossemicarbazonas/química , Células A549 , Reação de Cicloadição , Humanos , Células Jurkat , Estrutura Molecular , Neoplasias/metabolismo , Neoplasias/patologia
8.
Mediators Inflamm ; 2018: 5346413, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29507527

RESUMO

Interleukin-33 (IL-33) is an IL-1 family member, which exhibits both pro- and anti-inflammatory properties solely based on the type of the disease itself. Generally, IL-33 is expressed by both endothelial and epithelial cells and mediates its function based on the interaction with various receptors, mainly with ST2 variants. IL-33 is a potent inducer for the Th2 immune response which includes defence mechanism in brain diseases. Thus, in this paper, we review the biological features of IL-33 and the critical roles of IL-33/ST2 pathway in selected neurological disorders including Alzheimer's disease, multiple sclerosis, and malaria infection to discuss the involvement of IL-33/ST2 pathway during these brain diseases and its potential as future immunotherapeutic agents or for intervention purposes.


Assuntos
Proteína 1 Semelhante a Receptor de Interleucina-1/metabolismo , Interleucina-33/metabolismo , Doenças do Sistema Nervoso/metabolismo , Animais , Humanos , Transdução de Sinais/fisiologia
9.
Sensors (Basel) ; 18(6)2018 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-29899214

RESUMO

In the present study, a beneficial approach for the ultrasensitive and affordable naked eye detection and diagnosis of tuberculosis (TB) by utilizing plasmonic enzyme-linked immunosorbent assay (ELISA) via antibody-antigen interaction was studied. Here, the biocatalytic cycle of the intracellular enzymes links to the formation and successive growth of the gold nanoparticles (GNPs) for ultrasensitive detection. The formation of different colored solutions by the plasmonic nanoparticles in the presence of enzyme labels links directly to the existence or non-existence of the TB analytes in the sample solutions. For disease detection, the adapted protocol is based mainly on the conventional ELISA procedure that involves catalase-labeled antibodies, i.e., the enzymes consume hydrogen peroxide and further produce GNPs with the addition of gold (III) chloride. The amount of hydrogen peroxide remaining in the solution determines whether the GNPs solution is to be formed in the color blue or the color red, as it serves as a confirmation for the naked eye detection of TB analytes. However, the conventional ELISA method only shows tonal colors that need a high concentration of analyte to achieve high confidence levels for naked eye detection. Also, in this research, we proposed the incorporation of protein biomarker, Mycobacterium tuberculosis ESAT-6-like protein esxB (CFP-10), as a means of TB detection using plasmonic ELISA. With the use of this technique, the CFP-10 detection limit can be lowered to 0.01 µg/mL by the naked eye. Further, our developed technique was successfully tested and confirmed with sputum samples from patients diagnosed with positive TB, thereby providing enough evidence for the utilization of our technique in the early diagnosis of TB disease.


Assuntos
Proteínas de Bactérias/análise , Ensaio de Imunoadsorção Enzimática , Tuberculose/diagnóstico , Proteínas de Bactérias/imunologia , Ouro/química , Humanos , Peróxido de Hidrogênio/química , Peróxido de Hidrogênio/metabolismo , Limite de Detecção , Nanopartículas Metálicas/química , Mycobacterium tuberculosis/metabolismo , Tuberculose/microbiologia
10.
Int J Mol Sci ; 19(4)2018 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-29641433

RESUMO

The recently identified cytokines-interleukin (IL)-35 and interleukin (IL)-37-have been described for their anti-inflammatory and immune-modulating actions in numerous inflammatory diseases, auto-immune disorders, malignancies, infectious diseases and sepsis. Either cytokine has been reported to be reduced and in some cases elevated and consequently contributed towards disease pathogenesis. In view of the recent advances in utilizing cytokine profiles for the development of biological macromolecules, beneficial in the management of certain intractable immune-mediated disorders, these recently characterized cytokines (IL-35 and IL-37) offer potential as reasonable targets for the discovery of novel immune-modulating anti-inflammatory therapies. A detailed comprehension of their sophisticated regulatory mechanisms and patterns of expression may provide unique opportunities for clinical application as highly selective and target specific therapeutic agents. This review seeks to summarize the recent advancements in discerning the dynamics, mechanisms, immunoregulatory and anti-inflammatory actions of IL-35 and IL-37 as they relate to disease pathogenesis.


Assuntos
Doenças Autoimunes/etiologia , Doenças Cardiovasculares/etiologia , Interleucina-1/metabolismo , Interleucinas/metabolismo , Neoplasias/etiologia , Animais , Humanos , Interleucina-1/genética , Interleucinas/genética , Transdução de Sinais
11.
J Mater Sci Mater Med ; 28(9): 138, 2017 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-28791524

RESUMO

5-Fluororaucil (5-FU) as anti-cancer drug was reported to induce thymidine synthase (TS) overexpression and cancer cell resistance. To improve its therapeutic efficacy and selective targeting, here we developed a targeted delivery system mediated by the active ligand-folate receptor chemistry to deliver the 5-FU drug selectively into the tumor microenvironment. The preparation was achieved by exploring chitosan (CS)-biopolymer based system with folic acid (FA)-conjugation. The 5-FU@FACS-Mn:ZnS quantum dots (QDs) based on the histological assessment conducted in the 4T1 challenged mice showed an improved tumor remission in the liver, spleen and lungs. The 5-FU@FACS-Mn:ZnS composite induced anti-proliferative properties in these organs as compared to the free 5-FU drug. Unlike the 5-FU@FACS-Mn:ZnS treated groups which showed some specific morphological changes such as cell shrinkage without obvious presence of adipocytes, the excised section of the tumor in the untreated control group and the free 5-FU drug treated group showed necrotic and degenerated cells; these cells are multifocally distributed in the tumor mass with evidence of widely distributed adipocytes within the tumor mass. These findings suggest that the 5-FU@FACS-Mn:ZnS composite has a superior role during the induction of apoptosis in the 4T1 cells as compared to the free 5-FU drug treated groups. The results of the study therefore suggest that the impregnation of 5-FU anti-cancer drug within the FACS-Mn:ZnS system significantly improves its selective targeting efficacy, in addition to improving the anti-proliferative properties and attenuate possible tumor resistances to the 5-FU drug. The work discusses about the anti-metastatic effects of folic acid-bound 5-Fluororacil loaded Mn:ZnS quantum dots towards 4T1 cell line proliferation in mice based on the histological analysis.


Assuntos
Antineoplásicos/administração & dosagem , Fluoruracila/administração & dosagem , Fluoruracila/uso terapêutico , Compostos de Manganês/química , Neoplasias Experimentais/tratamento farmacológico , Sulfetos/química , Compostos de Zinco/química , Animais , Antimetabólitos Antineoplásicos/administração & dosagem , Antimetabólitos Antineoplásicos/uso terapêutico , Quitosana , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Pontos Quânticos
12.
Sensors (Basel) ; 17(7)2017 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-28671559

RESUMO

A semiconducting water-soluble core-shell quantum dots (QDs) system capped with thiolated ligand was used in this study for the sensitive detection of glucose in aqueous samples. The QDs selected are of CdSe-coated ZnS and were prepared in house based on a hot injection technique. The formation of ZnS shell at the outer surface of CdSe core was made via a specific process namely, SILAR (successive ionic layer adsorption and reaction). The distribution, morphology, and optical characteristics of the prepared core-shell QDs were assessed by transmission electron microscopy (TEM) and spectrofluorescence, respectively. From the analysis, the results show that the mean particle size of prepared QDs is in the range of 10-12 nm and that the optimum emission condition was displayed at 620 nm. Further, the prepared CdSe/ZnS core shell QDs were modified by means of a room temperature ligand-exchange method that involves six organic ligands, L-cysteine, L-histidine, thio-glycolic acid (TGA or mercapto-acetic acid, MAA), mercapto-propionic acid (MPA), mercapto-succinic acid (MSA), and mercapto-undecanoic acid (MUA). This process was chosen in order to maintain a very dense water solubilizing environment around the QDs surface. From the analysis, the results show that the CdSe/ZnS capped with TGA (CdSe/ZnS-TGA) exhibited the strongest fluorescence emission as compared to others; hence, it was tested further for the glucose detection after their treatment with glucose oxidase (GOx) and horseradish peroxidase (HRP) enzymes. Here in this study, the glucose detection is based on the fluorescence quenching effect of the QDs, which is correlated to the oxidative reactions occurred between the conjugated enzymes and glucose. From the analysis of results, it can be inferred that the resultant GOx:HRP/CdSe/ZnS-TGA QDs system can be a suitable platform for the fluorescence-based determination of glucose in the real samples.


Assuntos
Pontos Quânticos , Compostos de Cádmio , Glucose , Compostos de Selênio , Sulfetos , Sulfato de Zinco
13.
Int J Mol Sci ; 16(5): 10562-77, 2015 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-26006226

RESUMO

In recent years, molecularly-imprinted polymers (MIPs) have attracted the attention of several researchers due to their capability for molecular recognition, easiness of preparation, stability and cost-effective production. By taking advantage of these facts, Hg(II) imprinted and non-imprinted copolymers were prepared by polymerizing mercury nitrate stock solution (or without it) with methacrylic acid (MAA), 2-hydroxyl ethyl methacrylate (HEMA), methanol and ethylene glycol dimethacrylate (EGDMA) as the monomer, co-monomer solvent (porogen) and cross-linker, respectively. Thus, the formed Hg(II) imprinted polymer was characterized by using Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), Brunauer, Emmett and Teller (BET) and thermal gravimetric analysis (TGA). The separation and preconcentration characteristics of Hg(II) imprinted polymer were investigated by solid phase extraction (SPE) procedures, and an optimal pH of 7 was investigated as ideal. The specific surface area of the Hg(II) imprinted polymer was found to be 19.45 m2/g with a size range from 100 to 140 µm in diameter. The maximum adsorption capacity was observed to be 1.11 mg/g of Hg(II) imprinted beads with 87.54% removal of Hg(II) ions within the first 5 min. The results of the study therefore confirm that the Hg(II) imprinted polymer can be used multiple times without significantly losing its adsorption capacity.


Assuntos
Mercúrio/isolamento & purificação , Impressão Molecular , Petróleo/análise , Polímeros/química , Extração em Fase Sólida , Adsorção , Metacrilatos/química , Impressão Molecular/métodos , Extração em Fase Sólida/métodos
14.
Heliyon ; 10(11): e31912, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38841468

RESUMO

An analytic design of a prototype filter for M-channel maximally decimated cosine-modulated Near Perfect Reconstruction (NPR) filter banks is proposed in this work. The prototype filter is created using the least-square (CLS) method with weighted constraints, which is one-dimensional and requires single-parameter optimization. Compared to existing approaches, this suggested method achieves rapid convergence by analytically determining the optimal step size, ensuring the 3 dB cutoff frequency at π/2 M. The simulation results for design examples outperform the techniques in the available literature in terms of amplitude and aliasing distortion, reaching distortion around 2.4489 × 10-4 and 3.4907 × 10-9, respectively. This optimization algorithm's usefulness is further demonstrated with the sub-band coding of ECG signals. Implementing optimal prototype filters has tangible real-world effects, especially in critical sectors like healthcare and communications, improving diagnostics accuracy, data transmission efficiency, and overall performance.

15.
ACS Omega ; 9(14): 16458-16468, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38617684

RESUMO

The limited solubility of graphene in water can be attributed to the existence of π-π bonds connecting its layers. Functionalized graphene or graphene oxide (GO) is frequently produced in order to overcome the shortcomings of graphene. Using density functional theory (DFT) calculation, functionalized graphene with various combinations of hydroxyl, epoxy, and carboxylic functional groups were investigated computationally. The study focused on the effects of functional group combinations on the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies, giving information about the chemical reactivity and stability of the molecules under investigation. Global chemical reactivity descriptors, including chemical hardness, softness, electronegativity, chemical potential, and electrophilicity index, were calculated to further elucidate the overall stability and reactivity of the molecules. The results demonstrated that the introduction of oxygen-containing functional groups on graphene significantly influenced its electronic properties, leading to variations in the chemical reactivity and stability. Molecular electrostatic potential (MEP) maps highlighted the susceptibility of specific regions to electrophilic and nucleophilic attacks. The flexibility and stability of functionalized graphene through root mean square fluctuation (RMSF) and root mean square deviation (RMSD) analyses indicate the stability of functionalized graphene in water. This comprehensive computational investigation provides valuable insights into the design and understanding of functionalized graphene for potential applications in drug delivery.

16.
Sci Rep ; 14(1): 3867, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38365987

RESUMO

Solar Photovoltaic (SPV) technology advancements are primarily aimed at decarbonizing and enhancing the resiliency of the energy grid. Incorporating SPV is one of the ways to achieve the goal of energy efficiency. Because of the nonlinearity, modeling of SPV is a very difficult process. Identification of variables in a lumped electric circuit model is required for accurate modeling of the SPV system. This paper presents a new state-of-the-art control technique based on human artefacts dubbed Drone Squadron Optimization for estimating 15 parameters of a three-diode equivalent model solar PV system. The suggested method simulates a nonlinear relationship between the P-V and I-V performance curves, lowering the difference between experimental and calculated data. To evaluate the adaptive performance in every climatic state, two different test cases with commercial PV cells, RTC France and photo watt-201, are used. The proposed method provides a more accurate parameter estimate. To validate the recommended approach's performance, the data are compared to the results of the most recent and powerful methodologies in the literature. For the RTC and PWP Photo Watt Cell, the DSO technique has the lowest Root Mean Square Error (RMSE) of 6.7776 × 10-4 and 0.002310324 × 10-4, respectively.

17.
Sci Rep ; 14(1): 8363, 2024 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-38600138

RESUMO

A comprehensive examination of human action recognition (HAR) methodologies situated at the convergence of deep learning and computer vision is the subject of this article. We examine the progression from handcrafted feature-based approaches to end-to-end learning, with a particular focus on the significance of large-scale datasets. By classifying research paradigms, such as temporal modelling and spatial features, our proposed taxonomy illuminates the merits and drawbacks of each. We specifically present HARNet, an architecture for Multi-Model Deep Learning that integrates recurrent and convolutional neural networks while utilizing attention mechanisms to improve accuracy and robustness. The VideoMAE v2 method ( https://github.com/OpenGVLab/VideoMAEv2 ) has been utilized as a case study to illustrate practical implementations and obstacles. For researchers and practitioners interested in gaining a comprehensive understanding of the most recent advancements in HAR as they relate to computer vision and deep learning, this survey is an invaluable resource.


Assuntos
Aprendizado Profundo , Humanos , Redes Neurais de Computação , Atividades Humanas
18.
Sci Rep ; 14(1): 7916, 2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38575667

RESUMO

In a DFIG grid interconnected system, the control of real and reactive power relies on various factors. This paper presents an approach to regulate the flow of real and reactive power using a Neural Tuning Machine (NTM) based on a recurrent neural network. The focus is on controlling the flow of reactive power from the rotor-side converter, which is proportional to the grid-side controller through a coupling voltage. The proposed NTM method leverages neural networks to fine-tune the parameters of the PI controller, optimizing performance for DFIG grid integration. By integrating dense plexus terminals, also known as dense connections, within the neural network, the control system achieves enhanced adaptability, robustness, and nonlinear dynamics, addressing the challenges of the grid. Grid control actions are based on the voltage profile at different bus locations, thereby regulating voltage. This article meticulously examines the analysis in terms of DFIG configuration and highlights the advantages of the neural tuning machine in controlling inner current loop parameters compared to conventional PI controllers. To demonstrate the robustness of the control algorithm, a MATLAB Simulink model is designed, and validation is conducted with three different benchmarking models. All calculations and results presented in the article strictly adhere to IEEE and IEC standards. This research contributes to advancing control methodologies for DFIG grid integration and lays the groundwork for further exploration of neural tuning methods in power system control.

19.
Bull Environ Contam Toxicol ; 91(6): 689-96, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24154614

RESUMO

In the present report, we explored the toxicological behaviour of engineered polystyrene-titanium-arsenate (PS-Ti-As) composite using cultured H9c2 cardiomyoblasts in vitro. From in vitro cytotoxicity studies, it appears that the composite can be toxic to the cardiac cells and the value of IC50 investigated to be the highest concentration of 500 µg mL(-1), during 16-24 h of incubation period. The cell morphological studies based on dual staining with acridine orange and ethidium bromide indicates that apoptosis is the dominating pathway of cell death. Furthermore, an enhanced DNA fragmentation, increased reactive oxygen species production and caspase release demonstrates the potential risks associated with the exposure of PS-Ti-As composite to the cardiac cells.


Assuntos
Arseniatos/toxicidade , Substâncias Perigosas/toxicidade , Poliestirenos/toxicidade , Titânio/toxicidade , Apoptose , Linhagem Celular , Espécies Reativas de Oxigênio/metabolismo , Testes de Toxicidade
20.
Gels ; 9(7)2023 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-37504460

RESUMO

In this study, we tested the biosorption capacity of trimethyl chitosan (TMC)-ZnO nanocomposite (NC) for the adsorptive removal of Escherichia coli (E. coli) in aqueous suspension. For the formation of ZnO NPs, we followed the green synthesis route involving Terminalia mantaly (TM) aqueous leaf extract as a reducing agent, and the formed ZnO particles were surface-coated with TMC biopolymer. On testing of the physicochemical characteristics, the TM@ZnO/TMC (NC) hydrogel showed a random spherical morphology with an average size of 31.8 ± 2.6 nm and a crystal size of 28.0 ± 7.7 nm. The zeta potential of the composite was measured to be 23.5 mV with a BET surface area of 3.01 m2 g-1. The spectral profiles of TM@ZnO/TMC NC hydrogel on interaction with Escherichia coli (E. coli) revealed some conformational changes to the functional groups assigned to the stretching vibrations of N-H, C-O-C, C-O ring, and C=O bonds. The adsorption kinetics of TM@ZnO/TMC NC hydrogel revealed the pseudo-second-order as the best fit mechanism for the E. coli biosorption. The surface homogeneity and monolayer adsorption of the TM@ZnO/TMC NC hydrogel reflects majorly the entire adsorption mechanism, observed to display the highest correlation for Jovanovic, Redlich-Peterson, and Langmuir's isotherm models. Further, with the use of TM@ZnO/TMC NC hydrogel, we measured the highest adsorption capacity of E. coli to be 4.90 × 10 mg g-1, where an in-depth mechanistic pathway was proposed by making use of the FTIR analysis.

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