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1.
Nat Commun ; 15(1): 5516, 2024 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-38951494

RESUMO

Nanoscale flows of liquids can be revealed in various biological processes and underlie a wide range of nanofluidic applications. Though the integral characteristics of these systems, such as permeability and effective diffusion coefficient, can be measured in experiments, the behaviour of the flows within nanochannels is still a matter of speculation. Herein, we used a combination of quadrupolar solid-state NMR spectroscopy, computer simulation, and dynamic vapour sorption measurements to analyse water diffusion inside peptide nanochannels. We detected a helical water flow coexisting with a conventional axial flow that are independent of each other, immiscible, and associated with diffusion coefficients that may differ up to 3 orders of magnitude. The trajectory of the helical flow is dictated by the screw-like distribution of ionic groups within the channel walls, while its flux is governed by external water vapour pressure. Similar flows may occur in other types of nanochannels containing helicoidally distributed ionic groups and be exploited in various nanofluidic lab-on-a-chip devices.

2.
Surg Open Sci ; 20: 82-93, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38973812

RESUMO

Introduction: New strategies and methods are needed to ensure that new generations can train and acquire surgical skills in a safe environment. Materials and methods: From January 2020 to October 2020, we performed a single centre, prospective observational cohort study. 19 participants (15 students, 4 residents) enrolled and 16 participants (13 students, 3 residents) successfully completed the curriculum. We performed a quantitative data analysis to evaluate its effectiveness in gaining and improving basic surgical endoscopic skills. Results: The time for single knot tying pre-, mid-, and post-training was reduced significantly, the average time (sec) decreased by 79.5 % (p < 0.001), the total linear distance (cm) by 74.5 % (p < 0.001) and the total angular distance (rad) by 71.7 % (p < 0.001). The average acceleration (mm/s2) increased by 20 % (p = 0.041). Additionally, the average speed increased by 23.5 % (p < 0.001), while motion smoothness (m/s3) increased by 20.4 % (p = 0.02). Conclusion: The obtained performance scores showed a significant increase in participants improving their basic surgical performance skills on the endoscopic simulator. This curriculum can be easily implemented in any surgical specialty as part of the residency training curriculum before first exposure in the operation room. All 16 participants recommended the implementation of such simulator training in their surgical training curriculum.

3.
Sci Rep ; 14(1): 7507, 2024 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-38553515

RESUMO

Multiple Sclerosis (MS) is a chronic autoimmune demyelinating disease of the central nervous system (CNS), with a largely unknown etiology, where mitochondrial dysfunction likely contributes to neuroaxonal loss and brain atrophy. Mirroring the CNS, peripheral immune cells from patients with MS, particularly CD4+ T cells, show inappropriate mitochondrial phenotypes and/or oxidative phosphorylation (OxPhos) insufficiency, with a still unknown contribution of mitochondrial DNA (mtDNA). We hypothesized that mitochondrial genotype in CD4+ T cells might influence MS disease activity and progression. Thus, we performed a retrospective cross-sectional and longitudinal study on patients with a recent diagnosis of either Clinically Isolated Syndrome (CIS) or Relapsing-Remitting MS (RRMS) at two timepoints: 6 months (VIS1) and 36 months (VIS2) after disease onset. Our primary outcomes were the differences in mtDNA extracted from CD4+ T cells between: (I) patients with CIS/RRMS (PwMS) at VIS1 and age- and sex-matched healthy controls (HC), in the cross-sectional analysis, and (II) different diagnostic evolutions in PwMS from VIS1 to VIS2, in the longitudinal analysis. We successfully performed mtDNA whole genome sequencing (mean coverage: 2055.77 reads/base pair) in 183 samples (61 triplets). Nonetheless, mitochondrial genotype was not associated with a diagnosis of CIS/RRMS, nor with longitudinal diagnostic evolution.


Assuntos
Doenças Desmielinizantes , Esclerose Múltipla Recidivante-Remitente , Esclerose Múltipla , Humanos , Esclerose Múltipla/genética , Linfócitos T , Estudos Transversais , Estudos Longitudinais , Estudos Retrospectivos , Esclerose Múltipla Recidivante-Remitente/genética , DNA Mitocondrial/genética , Linfócitos T CD4-Positivos , Genótipo
4.
Nanomaterials (Basel) ; 12(24)2022 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-36558233

RESUMO

The development of convenient, non-complicated, and cost-efficient processing techniques for packing low-density MOF powders for industry implementation is essential nowadays. To increase MOFs' availability in industrial settings, we propose the synthesis of a novel 3D Tb-MOF (1) and a simple and non-expensive method for its immobilization in the form of pellets and membranes in polymethacrylate (PMMA) and polysulphone (PSF). The photoluminescent properties of the processed materials were investigated. To simulate industrial conditions, stability towards temperature and humidity have been explored in the pelletized material. Water-adsorption studies have been carried out in bulk and processed materials, and because of the considerable capacity to adsorb water, proton-conduction studies have been investigated for 1.

5.
Molecules ; 27(22)2022 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-36432174

RESUMO

Due to the fast, emerging development of antibiotic-resistant bacteria, the need for novel, efficient routes to battle these pathogens is crucial; in this scenario, metal-organic frameworks (MOFs) are promising materials for combating them effectively. Herein, a novel Cu-MOF-namely 1-that displays the formula [Cu3L2(DMF)2]n (DMF = N,N-dimethylformamide) is described, synthesized by the combination of copper(II) and 3,4-dihydroxybenzoic acid (H3L)-both having well-known antibacterial properties. The resulting three-dimensional structure motivated us to study the antibacterial activity, adsorptive capacity and processability of the MOF in the form of pellets and membranes as a proof-of-concept to evaluate its future application in devices.


Assuntos
Antibacterianos , Cobre , Cobre/química , Ligantes , Adsorção , Antibacterianos/farmacologia
6.
Eur J Neurol ; 29(1): 247-256, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34536255

RESUMO

BACKGROUND AND PURPOSE: Multiple sclerosis (MS) is a chronic immune-mediated disease of the central nervous system with an undetermined etiology. Retinoids may have immunomodulatory effects that favorably influence MS progression. We aimed to explore the yet unknown relationship between exposure to retinoids and the risk of acquiring MS. METHODS: We performed a nationwide cohort study in the Danish population in the period 1998-2016, comparing MS incidence in three groups: users of systemic retinoids; users of topical retinoids (negative control group); and users of non-retinoid acne drugs (control group). We used data from the Danish Multiple Sclerosis Registry (DMSR), the Danish National Prescription Registry and the Danish National Patient Registry. Linkage was obtained through the personal identification number (CPR number). We addressed confounding by three-way propensity score (PS)-matching weights. Additionally, to evaluate a cumulative dose-response effect for systemic retinoids on MS incidence, we conducted a case-control study, nested within the cohort. RESULTS: A total of 257,193 users of non-retinoid acne drugs, 130,560 users of topical retinoids, and 75,610 users of systemic retinoids were included. Systemic retinoid use was not associated with a reduced risk of MS compared to non-retinoid acne drug use in crude (hazard ratio [HR] 0.80, 95% confidence interval [CI] 0.61 to 1.05]) and weighted analyses (HR 0.89, 95% CI 0.67 to 1.20). There was no evidence of a cumulative dose-response association between systemic retinoids and MS incidence. CONCLUSIONS: Use of systemic retinoids was not associated with a reduced incidence of MS compared to use of non-retinoid acne drugs in this study.


Assuntos
Esclerose Múltipla , Retinoides , Estudos de Casos e Controles , Estudos de Coortes , Dinamarca/epidemiologia , Humanos , Esclerose Múltipla/tratamento farmacológico , Esclerose Múltipla/epidemiologia , Retinoides/uso terapêutico
7.
Int J Mol Sci ; 22(21)2021 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-34769461

RESUMO

Despite a multitude of methods for the sample preparation, sequencing, and data analysis of mitochondrial DNA (mtDNA), the demand for innovation remains, particularly in comparison with nuclear DNA (nDNA) research. The Applied Biosystems™ Precision ID mtDNA Whole Genome Panel (Thermo Fisher Scientific, USA) is an innovative library preparation kit suitable for degraded samples and low DNA input. However, its bioinformatic processing occurs in the enterprise Ion Torrent Suite™ Software (TSS), yielding BAM files aligned to an unorthodox version of the revised Cambridge Reference Sequence (rCRS), with a heteroplasmy threshold level of 10%. Here, we present an alternative customizable pipeline, the PrecisionCallerPipeline (PCP), for processing samples with the correct rCRS output after Ion Torrent sequencing with the Precision ID library kit. Using 18 samples (3 original samples and 15 mixtures) derived from the 1000 Genomes Project, we achieved overall improved performance metrics in comparison with the proprietary TSS, with optimal performance at a 2.5% heteroplasmy threshold. We further validated our findings with 50 samples from an ongoing independent cohort of stroke patients, with PCP finding 98.31% of TSS's variants (TSS found 57.92% of PCP's variants), with a significant correlation between the variant levels of variants found with both pipelines.


Assuntos
Genoma Mitocondrial , Mitocôndrias/genética , Algoritmos , Medicina Legal , Variação Genética , Haplótipos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Medicina de Precisão , Análise de Sequência de DNA/métodos , Design de Software
8.
Biology (Basel) ; 10(10)2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34681079

RESUMO

Disease resistance of fish larvae may be improved by bath treatment in water containing immunostimulants. Pattern recognition receptors, such as TLR3, TLR7, and MDA5, work as an "early warning" to induce intracellular signaling and facilitate an antiviral response. A single bath of newly hatched larvae, with Astragalus, upregulated the expression of IFNα, IFNc, ISG15, MDA5, PKR, STAT1, TLR3, and TLR7 immune genes, on day 4 post treatment. Similar patterns were observed for Hyaluronic acid and Poly I:C. Increased expression was observed for ISG15, MDA5, MX, STAT1, TLR3, TLR7, and RSAD2, on day 9 for Imiquimod. Metabolic gene expression was stimulated on day 1 after immunostimulant bath in ULK1, MYC, SLC2A1, HIF1A, MTOR, and SIX1, in Astragalus, Hyaluronic acid, and Imiquimod. Expression of NOS2 in Poly I:C was an average fourfold above that of control at the same timepoint. Throughout the remaining sampling days (2, 4, 9, 16, 32, and 45 days post immunostimulant bath), NOS2 and IL1B were consistently overexpressed. In conclusion, the immunostimulants induced antiviral gene responses, indicating that a single bath at an early life stage could enable a more robust antiviral defense in fish. Additionally, it was demonstrated, based on gene expression data, that cell metabolism was perturbed, where several metabolic genes were co-regulated with innate antiviral genes.

10.
Front Med (Lausanne) ; 8: 672496, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34095177

RESUMO

Background and Aims: Atherosclerosis and osteoporosis share common risk factors, as well as inflammatory mechanisms. Our aim was to understand how atherosclerotic lesions are related with disturbances in bone. Methods: Gene expression of pro-inflammatory and bone metabolism related proteins (IL-1ß, IL-6, IL-17A, TNF, RANKL, OPG, COL1, CTSK, OCL, TRAP, CBFA1, DKK1, SOST, ADIPOQ, and ADIPOR1) were analyzed in arteries and bones from 45 deceased donors and adipose tissue was used as control. Additionally, in 139 patients with advanced atherosclerosis submitted to carotid endarterectomy we compared calcium content (Alizarin red) and plaque inflammatory scores (CD3+, CD68+, and adiponectin) of patients with normal bone mineral density (BMD) with those with low BMD and explored the associations between gene expression in atherosclerotic plaques and BMD. Serum levels of pro-inflammatory and bone related proteins were measured both in donors and patients. Associations were investigated by the Pearson or Spearman correlation tests, and multivariate regression analyzes were performed when justified. Results: Gene expression of bone remodeling and pro-inflammatory proteins correlated positively in bone and aorta, independently of age and sex of donors, but not in adipose tissue. The expression of bone formation genes was significantly higher in atheroma plaques from endarterectomized patients with normal vs. low BMD as well as inflammatory CD68+ scores, regardless of patients' age and sex, but not of body mass index. No relationship was observed between serum levels and gene expression levels of pro-inflammatory or bone remodeling proteins. Conclusions: Our results suggest that the relationship between bones and vessels in the context of atherosclerotic disease and osteoporosis may rely on the intrinsic connection between the tissues involved, independently of disease stage. Serum measurements of pro-inflammatory and bone-remodeling proteins do not accurately translate tissue pathologic processes.

11.
J Am Chem Soc ; 143(3): 1365-1376, 2021 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-33433193

RESUMO

Porous robust materials are typically the primary selection of several industrial processes. Many of these compounds are, however, not robust enough to be used as multifunctional materials. This is typically the case of Metal-Organic Frameworks (MOFs) which rarely combine several different excellent functionalities into the same material. In this report we describe the simple acid-base postsynthetic modification of isotypical porous rare-earth-phosphonate MOFs into a truly multifunctional system, maintaining the original porosity features: [Ln(H3pptd)]·xSolvent [where Ln3+ = Y3+ (1) and (Y0.95Eu0.05)3+ (1_Eu)] are converted into [K3Ln(pptd)]·zSolvent [where Ln3+ = Y3+ (1K) and (Y0.95Eu0.05)3+ (1K_Eu)] by immersing the powder of 1 and 1_Eu into an ethanolic solution of KOH for 48 h. The K+-exchanged Eu3+-based material exhibits a considerable boost in CO2 adsorption, capable of being reused for several consecutive cycles. It can further separate C2H2 from CO2 from a complex ternary gas mixture composed of CH4, CO2, and C2H2. This high adsorption selectivity is, additionally, observed for other gaseous mixtures, such as C3H6 and C3H8, with all these results being supported by detailed theoretical calculations. The incorporation of K+ ions notably increases the electrical conductivity by 4 orders of magnitude in high relative humidity conditions. The conductivity is assumed to be predominantly protonic in nature, rendering this material as one of the best conducting MOFs reported to date.

12.
Nanomaterials (Basel) ; 10(9)2020 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-32872554

RESUMO

The utilization of biobased materials for the fabrication of naturally derived ion-exchange membranes is breezing a path to sustainable separators for polymer electrolyte fuel cells (PEFCs). In this investigation, bacterial nanocellulose (BNC, a bacterial polysaccharide) and lignosulfonates (LS, a by-product of the sulfite pulping process), were blended by diffusion of an aqueous solution of the lignin derivative and of the natural-based cross-linker tannic acid into the wet BNC nanofibrous three-dimensional structure, to produce fully biobased ion-exchange membranes. These freestanding separators exhibited good thermal-oxidative stability of up to about 200 °C, in both inert and oxidative atmospheres (N2 and O2, respectively), high mechanical properties with a maximum Young's modulus of around 8.2 GPa, as well as good moisture-uptake capacity with a maximum value of ca. 78% after 48 h for the membrane with the higher LS content. Moreover, the combination of the conducting LS with the mechanically robust BNC conveyed ionic conductivity to the membranes, namely a maximum of 23 mS cm-1 at 94 °C and 98% relative humidity (RH) (in-plane configuration), that increased with increasing RH. Hence, these robust water-mediated ion conductors represent an environmentally friendly alternative to the conventional ion-exchange membranes for application in PEFCs.

13.
Chem Sci ; 11(24): 6305-6311, 2020 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-32874517

RESUMO

[Gd(H4nmp)(H2O)2]Cl·2H2O (1) converts into [Gd2(H3nmp)2]·xH2O (2) (x = 1 to 4) with a notable increase in proton conductivity. 1 is a charged layered material counter balanced by chloride ions, with proton conductivity values of 1.23 × 10-5 S cm-1 at 98% relative humidity (RH) and 40 °C. At 98% RH and 94 °C the observed conductivity is 0.51 S cm-1, being to date one of the highest values ever reported for a proton-conducting coordination polymer. This increase is observed during a structural transformation into 2 that occurs at high temperature and RH. While this remarkable conductivity is observed only after transformation and by maintaining high humidity conditions, as-synthesized 2 also shows a conductivity value of 3.79 × 10-2 S cm-1 at 94 °C and 98% RH, still ranked as one of the highest reported values. Moreover, it is shown that the key factor for high proton conduction is the unusual dynamic structural transformation with water insertion and release of chloride ions.

14.
ACS Appl Mater Interfaces ; 12(24): 27485-27492, 2020 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-32463652

RESUMO

Nanotubes of self-assembled dipeptides exemplified by diphenylalanine (FF) demonstrate a wide range of useful functional properties, such as high Young's moduli, strong photoluminescence, remarkable piezoelectricity and pyroelectricity, optical waveguiding, etc., and became the object of intensive research due to their ability to combine electronic and biological functions in the same material. Two types of nanoconfined water molecules (bound water directly interacting with the peptide backbone and free water located inside nanochannels) are known to play a key role in the self-assembly of FF. Bound water provides its structural integrity, whereas movable free water influences its functional response. However, the intrinsic mechanism of water motion in FF nanotubes remained elusive. In this work, we study the sorption properties of FF nanotubes directly considering them as a microporous material and analyze the free water self-diffusion at different temperatures. We found a change in the regime of free water diffusion, which is attributed to water cluster size in the nanochannels. Small clusters of less than five molecules per unit cell exhibit ballistic diffusion, whereas, for larger clusters, Fickian diffusion occurs. External conditions of around 40% relative humidity at 30 °C enable the formation of such large clusters, for which the diffusion coefficient reaches 1.3 × 10-10 m2 s-1 with an activation energy of 20 kJ mol-1, which increases to attain 3 × 10-10 m2 s-1 at 65 °C. The observed peculiarities of water self-diffusion along the narrow FF nanochannels endow this class of materials with a new functionality. Possible applications of FF nanotubes in nanofluidic devices are discussed.


Assuntos
Nanotubos de Peptídeos/química , Peptídeos/química , Fenilalanina/química
15.
Carbohydr Polym ; 230: 115604, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31887959

RESUMO

Conductive natural-based separators for application in polymer electrolyte fuel cells (PEFCs) were fabricated by combining a bacterial polysaccharide, i.e. bacterial cellulose (BC), and an algae sulphated polysaccharide, i.e. fucoidan (Fuc). The diffusion of fucoidan aqueous solution containing a natural-based cross-linker, viz. tannic acid, into the wet BC nanofibrous three-dimensional network, followed by thermal cross-linking, originated fully bio-based proton exchange membranes (PEMs). The PEMs present thermal-oxidative stability in the range of 180-200 °C and good dynamic mechanical performance (storage modulus ≥ 460 MPa). Additionally, the BC/Fuc membranes exhibit protonic conductivity that increases with increasing relative humidity (RH), which is a typical feature for numerous water-mediated proton conductors. The traditional Arrhenius-type plots demonstrate a linear behaviour with a maximum protonic conductivity of 1.6 mS cm-1 at 94 °C and 98 % RH. The results showed that these fully bio-based conductive membranes have potential as eco-friendly alternatives to other PEMs for application in PEFCs.


Assuntos
Fontes de Energia Bioelétrica , Celulose/análogos & derivados , Membranas Artificiais , Polissacarídeos/química , Prótons , Condutividade Elétrica , Fucus/química , Temperatura Alta , Oxirredução
16.
Ciênc. Saúde Colet. (Impr.) ; 24(12): 4605-4620, dez. 2019. tab, graf
Artigo em Português | LILACS | ID: biblio-1055738

RESUMO

Resumo O artigo objetiva identificar as estratégias utilizadas, para participação do paciente na segurança do cuidado de saúde. Revisão sistemática, norteada pelas recomendações do modelo PRISMA, nos bancos de dados: Scopus, WOS e Medline. Limitou-se a busca a estudos realizados entre janeiro de 2001 e julho de 2016, redigidos em português, inglês ou espanhol. Foram incluídos estudos observacionais, descritivos, qualitativos e/ou epidemiológicos, que descrevessem a metodologia de elaboração e/ou aplicação de, pelo menos, uma estratégia de inclusão dos pacientes na melhoria da segurança dos cuidados. A qualidade metodológica dos artigos foi avaliada usando a ferramenta Cochrane. Para analisar os resultados se fez uma análise temática. Após leitura de títulos, resumos e aplicação de critérios de exclusão, 19 artigos foram selecionados. Nestes se identificam estratégias de mobilização dos pacientes para a segurança dos cuidados, estratégias para promover a participação ativa dos pacientes na segurança dos cuidados e estratégias de solicitação de informação ao paciente sobre a segurança dos cuidados. Há na literatura diversas estratégias que promovem a participação do paciente na segurança dos cuidados, que têm formas e métodos concretos de implementação, bem como objetivos distintos para o seu uso.


Abstract The scope of this article was to identify the strategies used for the participation of the patient in healthcare security in hospital and outpatient environments. It involved a systematic review of the literature based on the recommendations of the PRISMA model on the Scopus, WOS and Medline databases. The search was restricted to studies written in Portuguese, English or Spanish conducted between January 2001 and July 2016. Observational, descriptive, qualitative and/or epidemiological studies that described a development/appliance methodology using at least one patient security improvement strategy of inclusion were included. The methodological quality of the studies was assessed using the randomized Cochrane risk-of-bias tool. Thematic analyses were performed in order to analyze the results. After the application of criteria of title, abstract analysis and exclusion, 19 studies were selected. In these studies, patient security strategies that promoted patients' active participation on patient security and information request strategies were identified. In the literature, sundry strategies promoting patient participation on healthcare security, with concrete implementation methods, as well as distinct purposes for their use, were encountered.


Assuntos
Humanos , Participação do Paciente , Gestão da Segurança/métodos , Segurança do Paciente , Entrevistas como Assunto , Grupos Focais , Assistência Ambulatorial/normas , Hospitalização
17.
Cien Saude Colet ; 24(12): 4605-4620, 2019 Dec.
Artigo em Português | MEDLINE | ID: mdl-31778511

RESUMO

The scope of this article was to identify the strategies used for the participation of the patient in healthcare security in hospital and outpatient environments. It involved a systematic review of the literature based on the recommendations of the PRISMA model on the Scopus, WOS and Medline databases. The search was restricted to studies written in Portuguese, English or Spanish conducted between January 2001 and July 2016. Observational, descriptive, qualitative and/or epidemiological studies that described a development/appliance methodology using at least one patient security improvement strategy of inclusion were included. The methodological quality of the studies was assessed using the randomized Cochrane risk-of-bias tool. Thematic analyses were performed in order to analyze the results. After the application of criteria of title, abstract analysis and exclusion, 19 studies were selected. In these studies, patient security strategies that promoted patients' active participation on patient security and information request strategies were identified. In the literature, sundry strategies promoting patient participation on healthcare security, with concrete implementation methods, as well as distinct purposes for their use, were encountered.


O artigo objetiva identificar as estratégias utilizadas, para participação do paciente na segurança do cuidado de saúde. Revisão sistemática, norteada pelas recomendações do modelo PRISMA, nos bancos de dados: Scopus, WOS e Medline. Limitou-se a busca a estudos realizados entre janeiro de 2001 e julho de 2016, redigidos em português, inglês ou espanhol. Foram incluídos estudos observacionais, descritivos, qualitativos e/ou epidemiológicos, que descrevessem a metodologia de elaboração e/ou aplicação de, pelo menos, uma estratégia de inclusão dos pacientes na melhoria da segurança dos cuidados. A qualidade metodológica dos artigos foi avaliada usando a ferramenta Cochrane. Para analisar os resultados se fez uma análise temática. Após leitura de títulos, resumos e aplicação de critérios de exclusão, 19 artigos foram selecionados. Nestes se identificam estratégias de mobilização dos pacientes para a segurança dos cuidados, estratégias para promover a participação ativa dos pacientes na segurança dos cuidados e estratégias de solicitação de informação ao paciente sobre a segurança dos cuidados. Há na literatura diversas estratégias que promovem a participação do paciente na segurança dos cuidados, que têm formas e métodos concretos de implementação, bem como objetivos distintos para o seu uso.


Assuntos
Participação do Paciente , Segurança do Paciente , Gestão da Segurança/métodos , Assistência Ambulatorial/normas , Grupos Focais , Hospitalização , Humanos , Entrevistas como Assunto
18.
Nanomaterials (Basel) ; 9(9)2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31510023

RESUMO

A membrane electrolyte that restricts the methanol cross-over while retaining proton conductivity is essential for better electrochemical selectivity in direct methanol fuel cells (DMFCs). Extensive research carried out to explore numerous blends and composites for application as polymer electrolyte membranes (PEMs) revealed promising electrochemical selectivity in DMFCs of carbon nanomaterial-based polymer composites. The present review covers important literature on different carbon nanomaterial-based PEMs reported during the last decade. The review emphasises the proton conductivity and methanol permeability of nanocomposite membranes with carbon nanotubes, graphene oxide and fullerene as additives, assessing critically the impact of each type of filler on those properties.

19.
Nanomaterials (Basel) ; 9(10)2019 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-31554306

RESUMO

The zeolitic imidazolate framework-8 (ZIF-8) combines a significantly high microporosity with an excellent thermal, chemical, and hydrothermal stability. Here, we demonstrated that ZIF-8 can display significant levels of protonic conductivity through a water-mediated surface transport mechanism associated to the presence of di-coordinated Zn ions revealed by X-ray photoelectron spectroscopy. A set of powders with particle sizes from 2.8 µm down to 80 nm studied by dynamic water vapour sorption analysis was used to demonstrate that water adsorbs predominantly in the micropore cavities of microcrystalline ZIF-8, whereas adsorption on the external surface becomes the dominant contribution for the nanostructured material. Impedance spectroscopy in turn revealed that the protonic conductivity of the nanocrystalline ZIF-8 was two orders of magnitude higher than that of the micron-sized powders, reaching approximately 0.5 mS·cm-1 at 94 °C and 98% relative humidity. Simple relations were derived in order to estimate the potential gains in water uptake and conductivity as a function of the particle size. This new strategy combining particle nanostructuring with surface defects, demonstrated here for one of the most know metal organic framework, is of general application to potentially boost the conductivity of other materials avoiding chemical functionalization strategies that in most if not all cases compromise their chemical stability, particularly under high humidity and high temperature conditions.

20.
Nanomaterials (Basel) ; 9(7)2019 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-31284559

RESUMO

Bacterial nanocellulose (BNC) is becoming an important substrate for engineering multifunctional nanomaterials with singular and tunable properties for application in several domains. Here, antimicrobial conductive nanocomposites composed of poly(sulfobetaine methacrylate) (PSBMA) and BNC were fabricated as freestanding films for application in food packaging. The nanocomposite films were prepared through the one-pot polymerization of sulfobetaine methacrylate (SBMA) inside the BNC nanofibrous network and in the presence of poly(ethylene glycol) diacrylate as cross-linking agent. The ensuing films are macroscopically homogeneous, more transparent than pristine BNC, and present thermal stability up to 265 °C in a nitrogen atmosphere. Furthermore, the films have good mechanical performance (Young's modulus ≥ 3.1 GPa), high water-uptake capacity (450-559%) and UV-blocking properties. The zwitterion film with 62 wt.% cross-linked PSBMA showed bactericidal activity against Staphylococcus aureus (4.3-log CFU mL-1 reduction) and Escherichia coli (1.1-log CFU mL-1 reduction), and proton conductivity ranging between 1.5 × 10-4 mS cm-1 (40 °C, 60% relative humidity (RH)) and 1.5 mS cm-1 (94 °C, 98% RH). Considering the current set of properties, PSBMA/BNC nanocomposites disclose potential as films for active food packaging, due to their UV-barrier properties, moisture scavenging ability, and antimicrobial activity towards pathogenic microorganisms responsible for food spoilage and foodborne illness; and also for intelligent food packaging, due to the proton motion relevant for protonic-conduction humidity sensors that monitor food humidity levels.

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