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1.
J Hazard Mater ; 470: 134155, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38552391

RESUMO

Iron complex regulated electrochemical reaction was triggered for revealing the reaction mechanism, degradation pathway, and applied potential of perfluorooctanoic acid (PFOA). The increased PMS concentrations, electrode spacing, and current density significantly enhanced PFOA elimination, with current density exhibiting a relatively strong interdependency to PFOA complete mineralization. The synergy between PMS and electrochemical reactions greatly accelerated PFOA decomposition by promoting the generation of key reaction sites, such as those for PMS activation and electrochemical processes, under various conditions. Furthermore, density functional theory calculations confirmed that the reciprocal transformation of Fe2+ and Fe3+ complexes was feasible under the electrochemical effect, further promoting the generation of active sites. The developed electrochemical oxidation with PMS reaction (EO/PMS) system can rapidly decompose and mineralize PFOA while maintaining strong tolerance to changing water matrices and organic and inorganic ions. Overall, it holds promise for use in treating and purifying wastewater containing PFOA.

2.
BMC Oral Health ; 24(1): 187, 2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38317203

RESUMO

BACKGROUND: Mastication is important for breaking down food, aiding swallowing and nutrients absorption, and is therefore fundamental to a child's development. Studies have shown poor masticatory function to be associated with younger age and presence of caries. However, studies of the association between masticatory function and malocclusion yielded contradictory results. The aim of this study is therefore to investigate the association between three-dimensional occlusal features with masticatory function, among preschool children in Hong Kong. METHODS: Self-administered questionnaires on masticatory function in three domains, namely general chewing difficulty, requiring help when eating different food types and increased preference for soft food were completed by parents. Information on non-nutritive sucking habits and basic demographics were also collected in the questionnaire. Clinical examinations were conducted to record three-dimensional occlusal features and presence of caries. Baseline investigations and one-year follow-ups were undertaken for 1,566 and 996 preschool children. Association of poor masticatory function with occlusal features, sucking habits and caries was investigated using chi-squared tests. Binomial logistic regressions were then carried out incorporating any significant factors identified. Longitudinal analysis of the one-year follow-up data was carried out to investigate whether improved occlusal features, sucking habits and caries resulted in better masticatory function. RESULTS: In the cross-sectional study, the first domain of general chewing difficulty was associated with caries and thumb/digit sucking. The second domain of requiring help when eating different food types was associated with the male sex, younger age, caries and pacifier use. The last domain of increased preference for soft foods was associated with caries and thumb/digit sucking. Occlusal features, including abnormal overjet and unilateral permanent molars not in contact, were significantly associated with poor masticatory function in the bivariate analyses, but were not significant in the logistic regressions. In the longitudinal analysis, general chewing difficulty was found to improve in those of older age and those with resolved anterior crossbite. Less help was required to eat meat in those with fewer caries. Similarly, less help was required to eat food containing bones in those with reduced pacifier use. Preferences for eating soft foods was reduced in those who developed a normal overjet. CONCLUSIONS: The study identified significant relationships between masticatory difficulties and factors associated with age, gender, active caries, and non-nutritive oral habits such as thumb/digit sucking and pacifier use. Younger children and males required more assistance with certain food types. Active caries and thumb/digit sucking habits contributed to general masticatory difficulties and preference for soft foods. The one-year follow-up indicated that improvement in masticatory function varies across age cohorts and were associated with improved occlusal features, such as resolution of anterior crossbite and normalized overjet, reduced pacifier use, and a decrease in the number of decayed teeth.


Assuntos
Má Oclusão , Humanos , Masculino , Pré-Escolar , Hong Kong , Seguimentos , Estudos Transversais , Sucção de Dedo , Comportamento de Sucção , Inquéritos e Questionários
3.
Integr Med Res ; 12(4): 100993, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37915438

RESUMO

Background: This study aimed to investigate clinical effectiveness of a structured eight-week mindfulness-based music therapy (MBMT) program on improving mood regulation in older women with blindness. This investigation compared a MBMT group with a mindfulness intervention (MI) group and a control group. Methods: Ninety-two older females with blindness from a residential setting in Hong Kong were recruited and randomly allocated to a MBMT (n = 31), MI (n = 30), or control (n = 31) group. Psychological measurements regarding mood regulation and general mood states (namely, Difficulties in Emotion Regulation Scale [DERS], Geriatric Depression Scale [GDS], and Depression Anxiety Stress Scales-21), were taken at pretest and posttest. Outcome assessors were blinded to group assignment. Results: Data was analyzed based on intention-to-treat basis. At posttest, DERS scores in the MBMT group (mean differences and 95% confidence interval: 12.1, 5.5 to 18.8) and the MI group (7.2, 0.5 to 13.8) were lower than that in the control group. GDS scores in the MBMT group (2.9, 1.7 to 4.0) and the MI group (1.7, 0.6 to 2.9) were lower than those in the control group. Compared with the MI group, the MBMT group improved emotional awareness sub-scores in DERS (2.1, 0.2 to 4.1) and appeared to lower depression in GDS scores (1.1, -0.0 to 2.3; p = 0.053). Conclusion: MBMT seems more beneficial than MI alone for improving emotional regulation in older women with blindness. The combination of mindfulness and music can generate a synergetic effect by enhancing both attention and appraisal components within the emotional-regulation process. Trial registration: ClinicalTrials.gov, NCT05583695.

4.
Int J Hyg Environ Health ; 253: 114224, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37523818

RESUMO

SARS-CoV-2 remains one of the biggest global health problems, which has already reached our wastewater through fecal shedding by COVID-19 patients. While the development of vaccines has mitigated the threats of the COVID-19 pandemic, the evolutionary dynamics of SARS-CoV-2 in wastewater lack monitoring and understanding. In this study, SARS-CoV-2 variants in wastewater were identified by analyzing 8511 wastewater-derived genome sequences from 9 countries from March 2020 to May 2023. The dominance of co-circulating variants was observed, namely B.1 in 2020, Alpha and Delta in 2021, then superseded by Omicron lineages in 2022 with a three-times increase. Mutations were also profiled, revealing nearly 5031 unique amino acid substitutions occurring approximately 371,591 times, some of which were associated with enhanced viral transmission and fitness. This study provided the first long-term multi-country overview of the prevalence of co-circulating SARS-CoV-2 lineages and mutations in wastewater and showed its comparison with conventional epidemiological surveillance. The results highlight the ability of wastewater-based genome monitoring to supplement clinical surveillance efforts in rapidly detecting viruses up to the strain level to keep track of their potential transmission routes and evolutionary dynamics.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , COVID-19/epidemiologia , Pandemias , SARS-CoV-2/genética , Águas Residuárias
5.
Chem Sci ; 14(26): 7114-7125, 2023 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-37416716

RESUMO

The structure and chemistry of metal-organic frameworks or MOFs dictate their properties and functionalities. However, their architecture and form are essential for facilitating the transport of molecules, the flow of electrons, the conduction of heat, the transmission of light, and the propagation of force, which are vital in many applications. This work explores the transformation of inorganic gels into MOFs as a general strategy to construct complex porous MOF architectures at nano, micro, and millimeter length scales. MOFs can be induced to form along three different pathways governed by gel dissolution, MOF nucleation, and crystallization kinetics. Slow gel dissolution, rapid nucleation, and moderate crystal growth result in a pseudomorphic transformation (pathway 1) that preserves the original network structure and pores, while a comparably faster crystallization displays significant localized structural changes but still preserves network interconnectivity (pathway 2). MOF exfoliates from the gel surface during rapid dissolution, thus inducing nucleation in the pore liquid leading to a dense assembly of percolated MOF particles (pathway 3). Thus, the prepared MOF 3D objects and architectures can be fabricated with superb mechanical strength (>98.7 MPa), excellent permeability (>3.4 × 10-10 m2), and large surface area (1100 m2 g-1) and mesopore volumes (1.1 cm3 g-1).

6.
ACS Omega ; 8(14): 12636-12643, 2023 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-37065060

RESUMO

Healthy skin has a high vitamin C concentration that protects against ultraviolet (UV)-induced damage, promotes wound healing, and lowers cancer risk. The present contribution describes two drug delivery systems for topical administration of vitamin C. The electrospun poly(vinyl alcohol) (PVA) nanofiber carrier of vitamin C exhibits a burst release profile (66 mg/g/h followed by 6.3 mg/g/h). In comparison, a new composite PVA nanofiber-molecular capsule delivers vitamin C at a constant rate (8.2 mg/g/h) with a zeroth-order release profile for better therapeutic management. Both delivery systems protect vitamin C and afford increased heat stability. The molecular capsules of ß-cyclodextrin with the vitamin C inclusion complex are immobilized on cellulose acetate and electrosprayed onto an electrospun PVA nanofiber mat.

7.
Small ; 19(37): e2301561, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37096929

RESUMO

Atmospheric water harvesting is considered a viable source of freshwater to alleviate water scarcity in an arid climate. Water condensation tends to be more efficient on superhydrophobic surfaces as the spontaneous coalescence-induced droplet jumping on superhydrophobic surfaces enables faster condensate removal. However, poor water nucleation on these surfaces leads to meager water harvest. A conventional approach to the problem is to fabricate micro- and nanoscale biphilic structures. Nonetheless, the process is complex, expensive, and difficult to scale. Here, the authors present an inexpensive and scalable method based on manipulating the water-repellent coatings of superhydrophobic surfaces. Flexible siloxane can facilitate water nucleation, while a branched structure promotes efficient droplet jumping. Moreover, ToF-SIMS analysis indicated that branched siloxane provides a better water-repellent coating coverage than linear siloxane and the siloxanes comprise hydrophilic and hydrophobic molecular segments. Thus, the as-prepared superhydrophobic surface, TiO2 nanorods coated with branched siloxanes harvested eight times more water than a typical fluoroalkylsilane (FAS)-coated surface under a low 30% relative humidity and performed better than most reported biphasic materials.

8.
Small ; 19(32): e2300430, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37058085

RESUMO

A soft microbot assembled from individual magnetic microsphere scaffold (MMS) beads carrying mesenchymal stem cells (MSC) is navigated under magnetic actuation, where an oscillating field induces mechanical flexion to propel the microbot toward the target site. A seven-bead microbot attained a top translational speed of 205.6 µm s-1 (0.068 body length s-1 ) under 10 mT and 2 Hz field oscillation. The shallow flexion angle (10-24.5°) allows precision movements required to navigate narrow spaces. Upon arrival at the target site, the MMS beads unload their MSC cargo following exposure to a phosphate-buffered saline (PBS) solution, mimicking the extracellular fluid's sodium concentration. The released stem cells have excellent viability and vitality, promoting rapid healing (i.e., 83.2% vs 49%) in a scratch-wound assay. When paired with minimally invasive surgical methods, such as laparoscopy and endoscopic surgery, the microbot can provide precise stem cell delivery to hard-to-reach injury sites in the body to promote healing. Moreover, the microbot is designed to be highly versatile, with individual MMS beads customizable for cargoes of live cells, biomolecules, bionanomaterials, and pharmaceutical compounds for various therapeutic requirements.


Assuntos
Células-Tronco Mesenquimais , Microesferas , Células-Tronco , Cicatrização , Fenômenos Magnéticos
9.
Environ Res ; 219: 115000, 2023 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-36529328

RESUMO

Toluene is a prevalent pollutant in indoor environments and its removal is essential to maintain a healthy environment. Adsorption is one of the best alternatives for organic vapours removal, specially at low indoor concentrations. Metal Organic Frameworks (MOFs) and Ionic Liquids (ILs) are potential materials for this mean. In this work, the synthesis and application of IL/MOF composite materials for toluene removal is reported. Loading [BMIM][CH3COO] ionic liquid into MIL101 porous structure improves parent materials affinity towards toluene capture by two orders of magnitude (as Henry's constants, attesting to their synergy). MIL101(Cr) and absorption in [BMIM][CH3COO] IL is best described by Henry's Law, while the Langmuir adsorption model predicts toluene adsorption on [BMIM][CH3COO]/MIL101(Cr) better than Freundlich and Toth equations. Diffusional and kinetics models revealed that toluene diffusion is the rate limiting step for pristine MIL101. Kinetic and diffusion rates were systematically improved upon the incorporation of the ionic liquid due to shorter toluene hops with the adsorbed IL and the increased hydrophobicity in the composites making the sorption more favourable. This study provides a systematic analysis and modelling of the toluene capture process in IL/MOF composites aiding a better understanding of the sorption process in these novel materials.


Assuntos
Poluentes Ambientais , Líquidos Iônicos , Estruturas Metalorgânicas , Tolueno/química , Líquidos Iônicos/química , Gases
10.
Environ Res ; 215(Pt 3): 114341, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36179882

RESUMO

Indoor exposure to volatile organic compounds (VOCs) is detrimental to the health of the occupants, and their removal is crucial in maintaining good air quality. Novel adsorbents prepared by modifying Metal-Organic Frameworks (MOFs), MIL101 (Cr), UiO-66, and UiO-66-NH2 with [BMIM][CH3COO] ionic liquid, were characterized and tested for toluene adsorption. [BMIM][CH3COO]/MIL101 performed best with a fast sorption rate, large sorption capacity, and good regenerability. It displays synergistic interactions between the IL and MOF. Adding one weight percent [BMIM][CH3COO] to UiO-66 and UiO-66-NH2 has a synergistic effect with respective 14% and 5% enhancements sorption over calculated values. The strong interactions between IL and UiO-66 and UiO-66-NH2, as observed in their thermogravimetric data, results in poor toluene sorption for 10 wt% [BMIM][CH3COO] loadings. This work provides a basis for IL modification of MOFs for enhanced sorption of VOCs for air treatment.


Assuntos
Líquidos Iônicos , Estruturas Metalorgânicas , Compostos Orgânicos Voláteis , Adsorção , Ácidos Ftálicos , Tolueno
11.
Sci Rep ; 12(1): 4872, 2022 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-35318346

RESUMO

This work describes a versatile electrospinning equipment with rapid, independent, and precise x-y-z movements for large-area depositions of electrospun fibers, direct writing or assembly of fibers into sub-millimeter and micron-sized patterns, and printing of 3D micro- and nanostructures. Its versatility is demonstrated thought the preparation of multilayered functional nanofibers for wound healing, nanofiber mesh for particle filtration, high-aspect ratio printed lines, and freestanding aligned nanofibers.

12.
Water Res ; 215: 118259, 2022 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-35294910

RESUMO

Polyfluoroalkyl and perfluoroalkyl chemicals (PFCs) widely used in lubricants, surfactant, textiles, paper coatings, cosmetics, and fire-fighting foams can release a large deal of organics contaminants into wastewater and pose great risks to the health of humans and eco-environments. Although advanced oxidation processes can effectively deconstruct various organic contaminants via reactive radicals, the stable structure of PFCs makes it difficult to be degraded. Here, we confirm that electrochemical oxidation process coupled with peroxymonosulfate (PMS) reaction can efficiently destroy stable structure of PFCs via electron transfer and meanwhile completely degrade PFCs via generated active radicals. We further studies via capturing and scavenging radicals, and DFT calculations find that electron hydroxyl radials play a dominant role in degrading PFCs. Based on the calculations of adsorption energy and molecular orbital energy we further demonstrate that many active sites on the surface of Ti4O7 (1 0 4) plane can rapidly take part in electrochemical reaction for generating radials and removing organic contaminants. These results give a promising insight towards high-effective and deep degradation of PFCs via electrochemical reaction coupled with advanced oxidation processes, as well as providing guidance and technical support for the remove of multiple organic contaminants.


Assuntos
Ácidos Alcanossulfônicos , Fluorocarbonos , Transporte de Elétrons , Elétrons , Humanos
13.
Water Res ; 207: 117849, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34785408

RESUMO

Perfluorooctane sulfonate (PFOS), normally present in groundwater and surface water, is an emerging environmental contaminants, but is extremely difficult to be degraded due to high energy of the C-F bond. Here, an electrocoagulation (EC) technique coupled with peroxymonosulfate (PMS) activation was used to deeply degrade PFOS. Results showed that approximately 100% PFOS was removed from the solution in the monopolar serial (MS) mode within 60 min and achieved a high kinetic rate of 0.074 min-1, which was significantly higher than those of reported studies (Table S3). Energy consumption (2.06 kWh/kg) in the MS mode was significantly lower than that of Al (52.30 kWh/kg) and Zn (213.50 kWh/kg) electrodes, which further confirmed the potential application prospects of EC technique. The quenching experiments, electron spin response (ESR) analysis, and DFT calculations can verify that ·OH was the main radical from the reaction of Fe2+-OH reaction site with PMS. In addition, results from fluorine balance and TOC removal also indicated the complete mineralization and degradation of PFOS in the EC process. Quantum chemical calculations can confirm the PFOS degradation mechanism and key active sites for direct electron transfer and radical attack. After five cycle operations of PFOS degradation, the EC process was still effective in degrading PFOS with a removal efficiency above 98%. Thus, this work provided a novel alternative for the high-effective treatment of PFOS from contaminated environmental water bodies.


Assuntos
Ácidos Alcanossulfônicos , Fluorocarbonos , Poluentes Químicos da Água , Domínio Catalítico , Eletrocoagulação , Fluorocarbonos/análise , Peróxidos , Poluentes Químicos da Água/análise
14.
J Am Chem Soc ; 143(1): 196-205, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33320650

RESUMO

A unique 1D nanostructure of Pt@CeO2-BDC was prepared from Pt@CeBDC MOF. The Pt@CeO2-BDC was rich in oxygen vacancies (i.e., XPS Oß/(Oα + Oß) = 39.4%), and on the catalyst, the 2 nm Pt clusters were uniformly deposited on the 1D mesoporous polycrystalline CeO2. Toluene oxidation was conducted in a spectroscopic operando Raman-online FTIR reactor to elucidate the reaction mechanism and establish the structure-activity relationship. The reaction proceeds as follows: (I) adsorption of toluene as benzoate intermediates on Pt@CeO2-BDC at low temperature by reaction with surface peroxide species; (II) reaction activation and ring-opening involving lattice oxygen with a concomitant change in defect densities indicative of surface rearrangement; (III) complete oxidation to CO2 and H2O by lattice oxygen and reoxidation of the reduced ceria with consumption of adsorbed oxygen species. The Pt clusters, which mainly exist as Pt2+ with minor amounts of Pt0 and Pt4+ on the surface, facilitated the adsorption and reaction activation. The Pt-CeO2 interface generates reduced ceria sites forming nearby adsorbed peroxide at low temperature that oxidize toluene into benzoate species by a Langmuir-Hinshelwood mechanism. As the reaction temperature increases, the role of lattice oxygen becomes important, producing CO2 and H2O mainly by the Mars-van Krevelen mechanism.

15.
Dement Neuropsychol ; 14(4): 430-433, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33354298

RESUMO

Dementia causes disorders in multiple higher cortical functions. Visual impairment could further impact cognition in those with dementia. This study reports the results of a computerized attention training program in a patient with dementia and visual impairment. The case involves a 98-year-old woman with bilateral maculopathy and moderate dementia. The program consisted of pre- and post-assessments and training sessions. Assessments included the Cantonese version of the Mini-Mental State Examination, the digit span forward test, the Chinese version of the Verbal Learning Test (CVVLT), and the Test of Attentional Performance (TAP). Training sessions were conducted once to twice a week for a total of 8 45-minute sessions. The participant showed a decrease in the CVVLT score and improvements in TAP parameters. The results indicated that, in visually impaired older adults with dementia, attention and processing speed (measured by a sensitive test such as TAP) could potentially be improved with appropriate computerized training.


A demência causa distúrbios em várias funções corticais superiores. O comprometimento da visão pode impactar ainda mais a cognição em pessoas com demência. Este estudo relata os resultados de um programa de treinamento computadorizado de atenção em um paciente com demência e deficiência visual, uma mulher de 98 anos com maculopatia bilateral e demência moderada. O programa consistia em avaliações e pré- e pós-sessões de treinamento. As avaliações incluíram o Mini-Exame do Estado Mental em Cantonês, o teste de extensão de dígitos, a versão chinesa do Teste de Aprendizagem Verbal (CVVLT) e o Teste de Desempenho de Atenção (TAP). As sessões de treinamento foram realizadas uma a duas vezes por semana, com um total de 8 sessões de 45 minutos. A paciente apresentou diminuição no escore CVVLT e melhora nos parâmetros TAP. Os resultados indicaram que em idosos com deficiência visual com demência, a atenção e a velocidade de processamento (medida por um teste sensível como o TAP) poderiam ser melhoradas com a realização de treinamento computadorizado adequado.

16.
Dement. neuropsychol ; 14(4): 430-433, Oct.-Dec. 2020. graf
Artigo em Inglês | LILACS | ID: biblio-1142837

RESUMO

ABSTRACT. Dementia causes disorders in multiple higher cortical functions. Visual impairment could further impact cognition in those with dementia. This study reports the results of a computerized attention training program in a patient with dementia and visual impairment. The case involves a 98-year-old woman with bilateral maculopathy and moderate dementia. The program consisted of pre- and post-assessments and training sessions. Assessments included the Cantonese version of the Mini-Mental State Examination, the digit span forward test, the Chinese version of the Verbal Learning Test (CVVLT), and the Test of Attentional Performance (TAP). Training sessions were conducted once to twice a week for a total of 8 45-minute sessions. The participant showed a decrease in the CVVLT score and improvements in TAP parameters. The results indicated that, in visually impaired older adults with dementia, attention and processing speed (measured by a sensitive test such as TAP) could potentially be improved with appropriate computerized training.


RESUMO. A demência causa distúrbios em várias funções corticais superiores. O comprometimento da visão pode impactar ainda mais a cognição em pessoas com demência. Este estudo relata os resultados de um programa de treinamento computadorizado de atenção em um paciente com demência e deficiência visual, uma mulher de 98 anos com maculopatia bilateral e demência moderada. O programa consistia em avaliações e pré- e pós-sessões de treinamento. As avaliações incluíram o Mini-Exame do Estado Mental em Cantonês, o teste de extensão de dígitos, a versão chinesa do Teste de Aprendizagem Verbal (CVVLT) e o Teste de Desempenho de Atenção (TAP). As sessões de treinamento foram realizadas uma a duas vezes por semana, com um total de 8 sessões de 45 minutos. A paciente apresentou diminuição no escore CVVLT e melhora nos parâmetros TAP. Os resultados indicaram que em idosos com deficiência visual com demência, a atenção e a velocidade de processamento (medida por um teste sensível como o TAP) poderiam ser melhoradas com a realização de treinamento computadorizado adequado.


Assuntos
Humanos , Atenção , Transtornos da Visão , Capacitação de Usuário de Computador , Demência
17.
Small ; 15(42): e1903525, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31448563

RESUMO

Mixed transition metal oxides (MTMOs) have enormous potential applications in energy and environment. Their use as catalysts for the treatment of environmental pollution requires further enhancement in activity and stability. This work presents a new synthesis approach that is both convenient and effective in preparing binary metal oxide catalysts (CeCuOx ) with excellent activity by achieving molecular-level mixing to promote aliovalent substitution. It also allows a single, pure MTMO to be prepared for enhanced stability under reaction by using a bimetallic metal-organic framework (MOF) as the catalyst precursor. This approach also enables the direct manipulation of the shape and form of the MTMO catalyst by controlling the crystallization and growth of the MOF precursor. A 2D CeCuOx catalyst is investigated for the oxidation reactions of methanol, acetone, toluene, and o-xylene. The catalyst can catalyze the complete reactions of these molecules into CO2 at temperatures below 200 °C, representing a significant improvement in performance. Furthermore, the catalyst can tolerate high moisture content without deactivation.

18.
Mater Sci Eng C Mater Biol Appl ; 102: 616-622, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31147033

RESUMO

Nanostructured Ag@SiO2-Penicillin was synthesized from high-purity Ag0 NPs with a mean particle size of about 10 nm produced by electromagnetic levitation gas condensation (ELGC) method. The silver and penicillin contents of the synthesized nano-antibiotic were about 34 wt% and 2.5 wt% respectively, as determined by ICP-OES and TGA analyses. The antibacterial properties and synergistic effects of nanostructured Ag@SiO2 and Ag@SiO2-Penicillin on killing the Methicillin-susceptible S. aureus (MSSA) and Methicillin-resistant S. aureus (MRSA) bacteria were also examined. The nanoparticles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Ag@SiO2-Penicillin NPs showed an outstanding antibacterial activity compared to Penicillin and Ag@SiO2 NPs. The Fractional inhibitory concentration (FIC) indexes were 0.54 and 0.52 against MSSA and MRSA bacteria respectively, illustrating the synergistic effects of Ag@SiO2-Penicillin NPs. In addition, Ag@SiO2-Penicillin NPs showed promising dose-dependent cytotoxicity effects indicating the protective effects emanating from anti-inflammatory properties of penicillin.


Assuntos
Fenômenos Eletromagnéticos , Nanoestruturas/química , Nanotecnologia/métodos , Penicilinas/síntese química , Dióxido de Silício/síntese química , Prata/química , Morte Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Humanos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Nanoestruturas/ultraestrutura , Tamanho da Partícula , Penicilinas/química , Penicilinas/farmacologia , Dióxido de Silício/química , Espectroscopia de Infravermelho com Transformada de Fourier , Eletricidade Estática , Termogravimetria , Difração de Raios X
19.
Phys Chem Chem Phys ; 20(9): 6431-6439, 2018 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-29443336

RESUMO

Graphite oxide powder was obtained using the modified Hummers' method and characterized using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The XPS results indicated that the epoxy groups were the main functional groups on the graphite oxide powder surface. The graphite oxide powder was then reacted with SO2 and NH3 gases, respectively, at 25 °C. The XPS and ToF-SIMS analyses of the surface of the reacted graphite oxide powder showed that the reactions mainly occurred in the epoxy groups. Bisulfate and amine groups were formed on the surface of the graphite oxide powder after the reactions between the graphite oxide powder and SO2 and NH3 gases. This work demonstrates a new method of removing SO2 and NH3 gases using graphite oxide powder.

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