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1.
Microb Pathog ; 195: 106890, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39208960

RESUMO

The toxicity of the contaminated powder contributed to toxic aflatoxins has been well-known in the literature. However, before this study, the specific fungal strain behind aflatoxin production remained unidentified. Our research aimed to isolate and identify fungi from the tainted sandwiches while also assessing the preservation of sandwiches in ambient conditions. The study pinpointed Aspergillus flavus as the fungus responsible for aflatoxin production. Analysis revealed that the sandwich samples contaminated with pure A. flavus exhibited a significant Aflatoxin B1 (AFB1) concentration of 55.2 ± 0.21 ng/g, accompanied by a spore count of 2 × 106 Colony-Forming Unit (CFU)/g after ten days. In contrast, sandwich samples contaminated with the unspecified fungi displayed a lower AFB1 content of 16.21 ± 0.42 ng/g, with a spore count of 2.2 × 102 CFU/g after the same duration. In the prevention study, the efficacy of the ethanol spray method for inhibiting aflatoxin from A. flavus was investigated. Results demonstrated that a 70 % ethanol concentration at a ratio of 2.0 % total weight of the sandwich proved highly effective, significantly impeding fungal growth. This method extended the preservation time by sevenfold compared to the control. Importantly, tests at 2.0 % ethanol of the sandwich weight did not detect aflatoxin presence.


Assuntos
Aflatoxina B1 , Aflatoxinas , Aspergillus flavus , Contaminação de Alimentos , Microbiologia de Alimentos , Aspergillus flavus/metabolismo , Aspergillus flavus/crescimento & desenvolvimento , Aflatoxina B1/metabolismo , Aflatoxina B1/análise , Contaminação de Alimentos/análise , Aflatoxinas/análise , Aflatoxinas/metabolismo , Esporos Fúngicos/crescimento & desenvolvimento , Etanol/metabolismo , Contagem de Colônia Microbiana , Fungos/metabolismo , Fungos/isolamento & purificação , Fungos/efeitos dos fármacos , Conservação de Alimentos/métodos
2.
Molecules ; 27(23)2022 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-36500557

RESUMO

Efforts to improve the solar power conversion efficiencies of binary bulk heterojunction-type organic photovoltaic devices using an active layer consisting of a poly-(3-alkylthiophene) (P3AT) homopolymer and a suitable fullerene derivative face barriers caused by the intrinsic properties of homopolymers. To overcome such barriers, researchers might be able to chemically tailor homopolymers by means of monomer ratio-balanced block copolymerization to obtain preferable properties. Triblock copolymers consisting of three components-3-hexylthiophene (HT), 3-butylthiophene (BT), and 3-octylthiophene (OT)-were synthesized via Grignard metathesis (GRIM) polymerization. The component ratios of the synthesized block copolymers were virtually the same as the feeding ratios of the monomers, a fact which was verified using 1H-NMR spectra. All the copolymers exhibited comparable crystalline and melting temperatures, which increased when one type of monomer became dominant. In addition, their power conversion efficiencies and photoluminescence properties were governed by the major components of the copolymers. Interestingly, the HT component-dominated block copolymer indicated the highest power conversion efficiency, comparable to that of its homopolymer, although its molecular weight was significantly shorter.


Assuntos
Energia Solar , Tiofenos , Tiofenos/química , Polímeros/química
3.
Molecules ; 25(17)2020 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-32842659

RESUMO

k-Oligocarrageenan (OC) is an effective biostimulator and a protector against disease infections for plants. However, the effect of OC molecular weight (MW) on plant growth is not fully understood. In this work, OCs with three different MWs (42, 17 and 4 kDa) was prepared by varying the degradation reaction time using ascorbic acid as a reagent. The product structure was confirmed by Fourier-transform infrared spectroscopy (FTIR) data. The growth promotion for maize (Zea mays L.) plants was investigated by foliar spray application of the prepared OCs. Field trials were carried out in two years, 2018 and 2019. The results showed that among treatments, OC with 4 kDa exhibited the best performance in both crop growth and grain yield parameters which indicated increases compared to the control in plant height (6.9-19.9%), length of ears (12.2%), diameter of ears (9.1%), fresh grain weight (17.8%), dry grain weight (20.0%) and grain yield (21.3%). Moreover, low MW OC augmented NP uptake in the plant growth while no effect on K uptake was observed. Therefore, OC with low MWs is potentially promising to apply as a promoter to enhance yield of crops.


Assuntos
Carragenina/farmacologia , Produtos Agrícolas , Desenvolvimento Vegetal/efeitos dos fármacos , Folhas de Planta , Zea mays , Produtos Agrícolas/genética , Produtos Agrícolas/crescimento & desenvolvimento , Cruzamentos Genéticos , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Zea mays/genética , Zea mays/crescimento & desenvolvimento
4.
Angew Chem Int Ed Engl ; 58(9): 2710-2714, 2019 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-30600872

RESUMO

Multiple sharp-edged gold nanostars were efficiently assembled on nanopipette tips through electrostatic interactions for use as a potent intracellular hypoxia-sensing Raman probe. Colloidal stability and surface immobilization were checked using scanning electron microscopy, light scattering, and zeta potential measurements. Site-specific intracellular hypoxia levels can be estimated in vitro and in vivo using Raman lancets (RL). Distinct Raman spectral changes for the nitro-(NO2 ) functional group of the redox marker 4-nitrothiophenol (4NTP) can be quantified according to the intracellular oxygen (O2 ) content, ranging from 1 % to 10 %. Redox potential changes in mitochondrial respiration were also examined through serial injections of inhibitors. 3D-cultured cells and in vivo tests were used to validate our method, and its application in the assessment of the aggressiveness of cancer cells by differentiating spectral changes between malignant and benign cells was demonstrated.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Hipóxia Celular , Sondas Moleculares/química , Nanopartículas/química , Oxigênio/análise , Análise de Célula Única , Animais , Células Cultivadas , Feminino , Humanos , Injeções Subcutâneas , Camundongos , Sondas Moleculares/administração & dosagem , Imagem Óptica , Oxirredução , Tamanho da Partícula , Análise Espectral Raman , Propriedades de Superfície
5.
Sensors (Basel) ; 17(11)2017 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-29140287

RESUMO

A surface-enhanced Raman scattering (SERS) detection method for environmental copper ions (Cu2+) was developed according to the vibrational spectral change of diethyldithiocarbamate (DDTC) on gold nanoparticles (AuNPs). The ultraviolet-visible (UV-Vis) absorption spectra indicated that DDTC formed a complex with Cu2+, showing a prominent peak at ~450 nm. We found Raman spectral changes in DDTC from ~1490 cm-1 to ~1504 cm-1 on AuNPs at a high concentration of Cu2+ above 1 µM. The other ions of Zn2+, Pb2+, Ni2+, NH4⁺, Mn2+, Mg2+, K⁺, Hg2+, Fe2+, Fe3+, Cr3+, Co2+, Cd2+, and Ca2+ did not produce such spectral changes, even after they reacted with DDTC. The electroplating industrial wastewater samples were tested under the interference of highly concentrated ions of Fe3+, Ni2+, and Zn2+. The Raman spectroscopy-based quantification of Cu2+ ions was able to be achieved for the wastewater after treatment with alkaline chlorination, whereas the cyanide-containing water did not show any spectral changes, due to the complexation of the cyanide with the Cu2+ ions. A micromolar range detection limit of Cu2+ ions could be achieved by analyzing the Raman spectra of DDTC in the cyanide-removed water.

6.
Bioorg Chem ; 63: 45-52, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26432615

RESUMO

A series of O-alkyl and O-acyl flavonoid derivatives was synthesized in high efficiency. Alkylation and acylation of 5-hydroxyflavonoids showed that the low reactivity hydroxyl group, 5-OH, well reacted with strong reagents whereas with weaker reagents, the different products were obtained dependently on structural characteristic of ring C of respective flavonoid. In order to evaluate anti-inflammatory activity, all compounds were tested for in vitro inhibition of bovine serum albumin denaturation and in vivo inhibition of carrageenan-induced mouse paw edema. Among them, the compounds 3, 3b, 4b and 4c demonstrated more effective anti-inflammatory activity than standard drugs (diclofenac sodium and ketoprofen) in both tests. Meanwhile, the flavonoids 2, 2c, 3a and 4b displayed anti-proliferative activity against MCF-7 cell lines. Triacetyl derivative of hesperetin 4b inducing degradation of DNA in MCF-7 cells was observed.


Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Antineoplásicos/farmacologia , Flavonoides/farmacologia , Animais , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/química , Antineoplásicos/síntese química , Antineoplásicos/química , Carragenina , Bovinos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Edema/induzido quimicamente , Edema/tratamento farmacológico , Feminino , Flavonoides/síntese química , Flavonoides/química , Humanos , Células MCF-7 , Masculino , Camundongos , Estrutura Molecular , Soroalbumina Bovina/efeitos dos fármacos , Relação Estrutura-Atividade
7.
Beilstein J Nanotechnol ; 15: 1227-1237, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39376727

RESUMO

This study introduces a highly efficient and straightforward method for synthesizing gold nanoparticles (AuNPs) within a glucosamine/alginate (GluN/Alg) nanocomposite via an ionotropic gelation mechanism in aqueous environment. The resulting nanocomposite, AuNPs@GluN/Alg, underwent thorough characterization using UV-vis, EDX, FTIR, SEM, TEM, SAED, and XRD analyses. The spherical AuNPs exhibited uniform size with an average diameter of 10.0 nm. The nanocomposites facilitated the recyclable reduction of organic dyes, including 2-nitrophenol, 4-nitrophenol, and methyl orange, employing NaBH4 as the reducing agent. Kinetic studies further underscored the potential of this nanocomposite as a versatile catalyst with promising applications across various industrial sectors.

8.
RSC Adv ; 14(29): 20466-20478, 2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-38946772

RESUMO

In recent years, smartphones have been integrated into rapid colorimetric sensors for heavy metal ions, but challenges persist in accuracy and efficiency. Our study introduces a novel approach to utilize biogenic gold nanoparticle (AuNP) sensors in conjunction with designing a lightbox with a color reference and machine learning for detection of Fe3+ ions in water. AuNPs were synthesized using the aqueous extract of Eleutherine bulbosa leaf as reductants and stabilizing agents. Physicochemical analyses revealed diverse AuNP shapes and sizes with an average size of 19.8 nm, with a crystalline structure confirmed via SAED and XRD techniques. AuNPs exhibited high sensitivity and selectivity in detection of Fe3+ ions through UV-vis spectroscopy and smartphones, relying on nanoparticle aggregation. To enhance image quality, we developed a lightbox and implemented a reference color value for standardization, significantly improving performance of machine learning algorithms. Our method achieved approximately 6.7% higher evaluation metrics (R 2 = 0.8780) compared to non-normalized approaches (R 2 = 0.8207). This work presented a promising tool for quantitative Fe3+ ion analysis in water.

9.
Beilstein J Nanotechnol ; 15: 954-964, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39108590

RESUMO

Theragnostic platforms, which integrate therapeutic and diagnostic capabilities, have gained significant interest in drug research because of to their potential advantages. This study reports the development of a novel multifunctional nanoparticle carrier system based on poly(ᴅ,ʟ-lactic-co-glycolic acid) (PLGA) for the targeted delivery of the chemotherapeutic agent chlorambucil (CHL) and the imaging agent IR780. The approach in this study incorporates Pluronic F127-folate onto the PLGA nanoparticles, which enables targeted delivery to folate receptor-expressing cancer cells. The F127-folate@PLGA/CHL/IR780 nanoparticles were formulated using a nanoprecipitation technique, resulting in small size, high homogeneity, and negative surface charge. Importantly, the folate-targeted nanoparticles demonstrated enhanced uptake and cytotoxicity in folate receptor-positive cancer cell lines (MCF-7 and HepG-2) compared to folate receptor-negative cells (HEK 293). Additionally, the F127-folate@PLGA/CHL/IR780 nanoparticles exhibited a lower IC50 value against cancer cells than non-targeted F127@PLGA/CHL/IR780 nanoparticles. These findings suggest that the developed F127-folate@PLGA/CHL/IR780 nanoparticles hold promise as a theragnostic system for targeted cancer therapy and diagnosis, leveraging the advantages of PLGA, folate targeting, and the integration of therapeutic and imaging agents.

10.
Beilstein J Nanotechnol ; 14: 781-792, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37441001

RESUMO

We present the in situ synthesis of silver nanoparticles (AgNPs) through ionotropic gelation utilizing the biodegradable saccharides lactose (Lac) and alginate (Alg). The lactose reduced silver ions to form AgNPs. The crystallite structure of the nanocomposite AgNPs@Lac/Alg, with a mean size of 4-6 nm, was confirmed by analytical techniques. The nanocomposite exhibited high catalytic performance in degrading the pollutants methyl orange and rhodamine B. The antibacterial activity of the nanocomposite is pH-dependent, related to the alterations in surface properties of the nanocomposite at different pH values. At pH 6, the nanocomposite demonstrated the highest antibacterial activity. These findings suggest that this nanocomposite has the potential to be tailored for specific applications in environmental and medicinal treatments, making it a highly promising material.

11.
Spectrochim Acta A Mol Biomol Spectrosc ; 268: 120709, 2022 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-34894570

RESUMO

In this study, a simple, eco-friendly and low-cost approach was used to fabricate silver nanoparticles (AgNPs) from an aqueous extract of Gleditsia australis (GA) fruit. The nanoparticles synthesized in the optimal condition have an average size of 14 nm. The peroxidase-like activity of GA-AgNP in the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in combination with hydrogen peroxide (H2O2) was investigated. Further, optimal conditions for the use of peroxidase-like catalytic activity in sensing applications were identified. The colourimetric detection of H2O2 showed a linear range of 1-8 mM with a limit of detection (LOD) of 0.34 mM. The oxidation of TMB (red-TMB) enables the detection of glucose, which is converted into H2O2 and gluconic acid in the presence of the enzyme glucose oxidase. The observations showed linearity from 0.05 to 1.5 mM with a LOD of 0.038 mM. Moreover, the blue colour of oxidized TMB (ox-TMB) was reduced according to ascorbic acid (AA) concentration, with a linear range of 0.03-0.14 mM and a LOD of 3.0 µM. The practical use of the sensing system for the detection of AA was studied using real fruit juice and showed good sensitivity. Hence, the easy-to-use peroxidase-like sensor provides a new platform for the detection of bioactive compounds in biological systems.


Assuntos
Gleditsia , Nanopartículas Metálicas , Ácido Ascórbico , Colorimetria , Frutas , Glucose , Peróxido de Hidrogênio , Limite de Detecção , Peroxidase , Prata
12.
RSC Adv ; 12(40): 25962-25976, 2022 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-36199614

RESUMO

The extraction of bioactive compounds, including essential oils and flavonoids, using organic solvents is a significant environmental concern. In this work, waste C. grandis peel was the ingredient used to extract essential oil and naringin by conducting a supercritical CO2 technique with a two stage process. In the first stage, the extraction with only supercritical CO2 solvent showed a significant enhancement of the d-limonene component, up to 95.66% compared with the hydro-distillation extraction (87.60%). The extraction of naringin using supercritical CO2 and ethanol as a co-solvent was done in the second stage of the process, followed by evaluating in vitro antimicrobial activity of both the essential oil and naringin. The essential oil indicated significant activity against M. catarrhalis (0.25 mg ml-1), S. pyogenes (1.0 mg ml-1), S. pneumoniae (1.0 mg ml-1). Whilst naringin gave good inhibition towards all tested microbial strains with MIC values in the range of 6.25-25.0 µM. In particular, naringin exhibited high antifungal activity against T. rubrum, T. mentagrophytes, and M. gypseum. The molecular docking study also confirmed that d-limonene inhibited bacterium M. catarrhalis well and that naringin possessed potential ligand interactions that proved the inhibition effective against fungi. Molecular dynamics simulations of naringin demonstrated the best docking model using Gromacs during simulation up to 100 ns to explore the stability of the complex naringin and crystal structure of enzyme 2VF5: PDB.

13.
J Agric Food Chem ; 69(21): 5882-5886, 2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-34028273

RESUMO

The diastereoselectivity of adducts in the addition reaction via the Felkin-Anh model is affected significantly by the steric effect of bulky groups. However, the influence of steric alkyl chain length has not been studied for the diastereoselectivity. In this work, we present a new strategy for the racemic synthesis of ß-methyl alcohols to obtain various diastereomer ratios using the Felkin-Anh model. The addition of alkyl Grignard reagents to α-methyl aldehydes afforded diastereomer ratios of threo/erythro ≈ 2:1, while the reduction in structurally related ketones using LiAlH4 afforded ratios of threo/erythro ≈ 1:1. The experimental data showed no effect of alkyl chain length on either side on the stereoselectivity of adducts. All synthesized analogues were evaluated for attractiveness to Rhynchophorus ferrugineus weevils in the field. Five novel derivatives, including two alcohols and three ketones, were found to attract weevils in the field trials. Among them, 3-methyldecan-4-one (5b) and 4-methyldecan-5-ol (11a) were found to be the most attractive to the insects.


Assuntos
Gorgulhos , Álcoois , Animais , Cetonas , Metanol
14.
Polymers (Basel) ; 13(19)2021 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-34641255

RESUMO

A series of poly-3-alkylthiophenes (P3ATs) with butyl (P3BT), hexyl (P3HT), and octyl (P3OT) side-chains and well-defined molecular weights (MWs) were synthesized using Grignard metathesis polymerization. The MWs of P3HTs and P3OTs obtained via gel permeation chromatography agreed well with the calculated MWs ranging from approximately 10 to 70 kDa. Differential scanning calorimetry results showed that the crystalline melting temperature increased with increasing MWs and decreasing alkyl side-chain length, whereas the crystallinity of the P3ATs increased with the growth of MWs. An MW-dependent red shift was observed in the UV-Vis and photoluminiscence spectra of the P3ATs in solution, which might be a strong evidence for the extended effective conjugation occurring in polymers with longer chain lengths. The photoluminescence quantum yields of pristine films in all polymers were lower than those of the diluted solutions, whereas they were higher than those of the phenyl-C61-butyric acid methyl ester-blended films. The UV-Vis spectra of the films showed fine structures with pronounced red shifts, and the interchain interaction-induced features were weakly dependent on the MW but significantly dependent on the alkyl side-chain length. The photovoltaic device performances of the P3BT and P3HT samples significantly improved upon blending with a fullerene derivative and subsequent annealing, whereas those of P3OTs mostly degraded, particularly after annealing. The optimal power conversion efficiencies of P3BT, P3HT, and P3OT were 2.4%, 3.6%, and 1.5%, respectively, after annealing with MWs of ~11, ~39, and ~38 kDa, respectively.

15.
Carbohydr Polym ; 251: 116998, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33142567

RESUMO

This work presents a simply new method for in situ synthesis of gold nanoparticles (AuNPs) using the biodegradable polysaccharides. A novel composite of lactose/alginate (Lac/Alg) could be prepared easily through ionotropic gelation mechanism which can reduce in situ gold ions into AuNPs. Lactose plays a crucial role as a reducing reagent which are demonstrated by FTIR analysis. The crystalline structure of AuNPs with a mean size of 10 nm has been confirmed by analysis techniques. The nanocomposite powder possesses highly catalytic performance for degradation of contaminants including 4-nitrophenol, methyl orange, rhodamine 6 G and rhodamine B. The dispersion solution of AuNPs@Lac/Alg was used as an effective probe for highly selective detection of Fe3+ ions. The detection mechanism replies on the aggregation of nanocomposite in the presence of Fe3+ ions. LOD value was found to be 0.8 µM in a linear range of 2.0-80.0 µM.


Assuntos
Alginatos/química , Compostos Férricos/análise , Lactose/química , Nanopartículas Metálicas/química , Nanocompostos/química , Biodegradação Ambiental , Catálise , Colorimetria/métodos , Corantes/isolamento & purificação , Ouro/química , Limite de Detecção , Nanopartículas Metálicas/ultraestrutura , Microscopia Eletrônica , Nanocompostos/ultraestrutura , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Poluentes Químicos da Água/isolamento & purificação
16.
Environ Sci Pollut Res Int ; 28(45): 63448-63463, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32588305

RESUMO

The emergent occurrence of sulfonamide species involving sulfadiazine (SDZ) and sulfamethazine (SMZ) in aquatic systems can cause a wide range of potential risks; hence, remediation strategies need to be necessary. Here, we develop the novel metal-organic framework-derived nanocomposite, and apply for the adsorption of SDZ and SMZ antibiotics. To assess the best-fitting kinetic (pseudo first-order, pseudo second-order) and isotherm (Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Redlich-Peterson, Sips, Toth, and Khan) models, a series of numerous statistical analysis was performed. Numerous error functions including squares of the errors (SSE), hybrid fractional error function (HYBRID), Marquardt's percent standard deviation (MPSD), and mean relative error (MRE) were also analyzed to assess the linear and nonlinear models. The results indicated that both linear and nonlinear kinetic models were mostly fitted well with pseudo second-order models (Radj)2 > 0.97. Although linear kinetics gave better (Radj)2, error functions (MRE, SSE, HYBRID, and MPSD) were mostly higher than those of nonlinear kinetics. For adsorption isotherm, nonlinear Redlich-Peterson was the most compatible model with extremely high adjusted coefficients of determination (Radj)2 ~ 1.0000. While nonlinear Langmuir model gave relatively high (Radj)2 (0.9898-0.9960) and acceptable error functions, we found the considerable difference of error functions and parameters among four types of linear Langmuir (Types I, II, III, IV). The findings indicate potential errors as selecting one of linearized Langmuir types in equilibrium study. It is suggested that nonlinear models should be applied for better fitness.


Assuntos
Estruturas Metalorgânicas , Nanocompostos , Poluentes Químicos da Água , Adsorção , Antibacterianos , Concentração de Íons de Hidrogênio , Cinética , Sulfonamidas , Termodinâmica
17.
Front Bioeng Biotechnol ; 8: 529365, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33102452

RESUMO

Cardiovascular diseases account for the number one cause of deaths in the world. Part of the reason for such grim statistics is our limited understanding of the underlying mechanisms causing these devastating pathologies, which is made difficult by the invasiveness of the procedures associated with their diagnosis (e.g., inserting catheters into the coronal artery to measure blood flow to the heart). Likewise, it is also difficult to design and test assistive devices without implanting them in vivo. However, with the recent advancements made in biomedical scanning technologies and computer simulations, image-based modeling (IBM) has arisen as the next logical step in the evolution of non-invasive patient-specific cardiovascular medicine. Yet, due to its novelty, it is still relatively unknown outside of the niche field. Therefore, the goal of this manuscript is to review the current state-of-the-art and the limitations of the methods used in this area of research, as well as their applications to personalized cardiovascular investigations and treatments. Specifically, the modeling of three different physics - electrophysiology, biomechanics and hemodynamics - used in the cardiovascular IBM is discussed in the context of the physiology that each one of them describes and the mechanisms of the underlying cardiac diseases that they can provide insight into. Only the "bare-bones" of the modeling approaches are discussed in order to make this introductory material more accessible to an outside observer. Additionally, the imaging methods, the aspects of the unique cardiac anatomy derived from them, and their relation to the modeling algorithms are reviewed. Finally, conclusions are drawn about the future evolution of these methods and their potential toward revolutionizing the non-invasive diagnosis, virtual design of treatments/assistive devices, and increasing our understanding of these lethal cardiovascular diseases.

18.
Environ Sci Pollut Res Int ; 27(6): 6148-6162, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31863387

RESUMO

In the present study, cost-effective, and environmentally friendly fabrication of silver and gold nanoparticles was performed by using aqueous extract of waste corn-cob. The formation of the metallic nanoparticles (MNPs) was optimized by UV-Vis method. The phytoconstituents were responsible for reduction of silver and gold ions to silver nanoparticles (CC-AgNPs) and gold nanoparticles (CC-AuNPs) which were demonstrated by Fourier-transform infrared (FTIR) spectroscopy while formation of AgCl was attributed to the presence of chloride ions in the aqueous extract. The crystalline nature of the AgNPs, AgCl, and AuNPs was confirmed using the X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns. Morphological studies showed that the synthesized CC-AgNPs existed in spherical shape with the size ranging from 2 to 28 nm possessing an average value of 11 nm while CC-AuNPs were present in the multiple shapes with size ranging from 5 to 50 nm possessing an average value of 35 nm. For studies on bioactive application, the CC-AgNPs exhibited a high antibacterial activity against three bacterial strains including Salmonella typhimurium, Bacillus cereus, and Staphylococcus aureus. In addition, the catalytic efficiency of MNPs was investigated for reduction of o-, m-, p-nitrophenols, and degradation of organic dyes including Eosin Y and Rhodamine 6G. The rate constants calculated from the kinetical data revealed that the biosynthesized nanoparticles are excellent catalysts in potential applications for treatment of wastewater. Graphical abstract .


Assuntos
Antibacterianos/química , Nanopartículas Metálicas/química , Zea mays , Ouro , Química Verde , Extratos Vegetais , Prata , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
19.
Materials (Basel) ; 12(17)2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31443413

RESUMO

In this study, we investigated sulfate-modified BiVO4 with the high photocatalytic activity synthesized by a sol-gel method in the presence of thiourea, followed by the annealing process at different temperatures. Its structure was characterized by thermal gravimetric analysis (TGA), powder X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS). The BiVO4 synthesized in the presence of thiourea and calcined at 600 °C (T-BVO-600) exhibited the highest photocatalytic degradation efficiency of methylene blue (MB) in water; 98.53% MB removal was achieved within 240 min. The reaction mechanisms that affect MB photocatalytic degradation on the T-BVO-600 were investigated via an indirect chemical probe method, using chemical agents to capture the active species produced during the early stages of photocatalysis, including 1,4-benzoquinone (scavenger for O2-), ethylenediaminetetraacetic acid disodium salt (scavenger for h+), and tert-butanol (scavenger for HO•). The results show that holes (h+) and hydroxyl radicals (HO•) are the dominant species of MB decomposition. Photoluminescence (PL) measurement results of terephthalic acid solutions in the presence of BiVO4 samples and BiVO4 powders confirm the involvement of hydroxyl radicals and the separation efficiency of electron-hole pairs in MB photocatalytic degradation. Besides, the T-BVO-600 exhibits good recyclability for MB removal, achieving a removal rate of above 83% after five cycles. The T-BVO-600 has the features of high efficiency and good recyclability for MB photocatalytic degradation. These results provide new insight into the purpose of improving the photocatalytic activity of BiVO4 catalyst.

20.
Colloids Surf B Biointerfaces ; 171: 49-57, 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30005290

RESUMO

Zidovudine (AZT) adsorbed on colloidal gold nanoparticles (AuNPs) undergoes pH-induced conformational changes according to spectral changes in surface-enhanced Raman scattering (SERS). In acidic pH values conditions, AZT assumes the C(2')-endo conformer, which binds more weakly to AuNPs than under neutral and alkaline conditions. In this study, density functional theory (DFT) calculations were performed; these calculations also supported the conformation-dependent binding energies. A lactobionic acid-conjugated PEGylated (LA-PEG-SH; molecular weight: 3400) unit was attached to AuNPs to target the asialoglycoprotein receptors overexpressed in hepatocarcinoma cells of Huh7 and SNU-354. The loading efficiency values were measured to be ∼44-49% and ∼66-68% at pH values of 7 and 10, respectively. At an acidic pH of 4.5, they were estimated to be only ∼35-38%. pH-dependent spectral changes were observed for the asymmetric stretching modes of the azide (NNN) bands at 2183 cm-1 (in acidic pH) and at 2129 cm-1 (in basic pH). Cell viability analysis indicated that the LA-PEG-capped, AZT-coated AuNPs specifically inhibited the growth of the targeted hepatocarcinoma cells with better cancer cell killing efficiency than was observed with the LA-PEG-capped AuNPs without AZT.


Assuntos
Dissacarídeos/química , Liberação Controlada de Fármacos , Coloide de Ouro/química , Polietilenoglicóis/química , Análise Espectral Raman , Zidovudina/química , Adsorção , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Dissacarídeos/farmacologia , Coloide de Ouro/farmacologia , Humanos , Concentração de Íons de Hidrogênio , Conformação Molecular , Tamanho da Partícula , Polietilenoglicóis/farmacologia , Teoria Quântica , Propriedades de Superfície , Zidovudina/farmacologia
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