Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 161
Filtrar
1.
Chemosphere ; 339: 139713, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37549744

RESUMO

Wastewater treatment is critically important for the existence of life on earth; however, this approach involves the removal of toxic metal contaminants and organic pollutants, requiring efficient adsorbent materials. Within this agenda, metal-organic frameworks (MOFs) appear to be potential materials due to their unique properties as efficient adsorbents, effective photocatalysts, and reliable semi-permeable membranes. Therefore, MOFs have undergone various modifications over the years without desirable success to improve adsorption capacity, hydro-stability, reaction kinetics, and reusability. Therefore, scientists around the world got engaged in MOF research for novel modifications, including defect engineering, carbonization, and membrane fabrication, at the laboratory scale. This review focuses on developing MOF-based adsorbents, photocatalysts, and semi-permeable membranes for wastewater treatment since 2015, emphasizing their structural-functional relationships. Finally, the challenges and opportunities with MOFs in wastewater treatment are also underlined for future efforts.


Assuntos
Poluentes Ambientais , Estruturas Metalorgânicas , Purificação da Água , Águas Residuárias , Adsorção
2.
ACS Omega ; 8(26): 23501-23509, 2023 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-37426205

RESUMO

Although perovskite solar cells (PSCs) have reached a record high conversion efficiency of 25.7%, the materials used to fabricate them invoke costly hole-transporting materials, such as spiro-OMeTAD, and expensive gold back contacts. The cost of fabrication of a solar cell or any other practical device is an important issue in their practical applications. In this study, we describe the fabrication of a low-cost, mesoscopic PSC, eliminating the use of expensive p-type semiconductors and substituting them with electronically conducting activated carbon, and the gold back contact with expanded graphite. The activated carbon hole transporting material was derived from readily available coconut shells and the expanded graphite from graphite attached to rock pieces of graphite vein banks. We drastically reduced the overall cell fabrication cost using these low-cost materials and added commercial value to discarded graphite and coconut shells. Under ambient conditions, our PSC gives a conversion efficiency of 8.60 ± 0.10 % at 1.5 AM simulated sunlight. We have identified the lower fill factor as the limiting factor for the low conversion efficiency. We believe that the lower cost of the materials used and the deceptively simple powder pressing method would compensate for the relatively lower conversion efficiency in its practical application.

3.
Parasitol Res ; 122(7): 1499-1507, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37093300

RESUMO

The helminth fauna present in the gut contents of Iberian adders, Vipera seoanei (Squamata: Viperidae), were characterised and analysed in respect to biological and eco-geographic factors that may affect the occurrence and diversity of helminths in this species. A total of 317 samples of preserved stomachs and intestines, covering the distributional range of V. seoanei, were examined. Similar to other Vipera species from the Iberian Peninsula, the helminth fauna was also impoverished in V. seoanei, but unlike other Vipera species from Central and East Europe, helminths were mostly found in adult vipers, and occurred in vipers located at the periphery of the species range, characterised by low elevation, high temperature and precipitation levels, and abundant pastures.


Assuntos
Helmintos , Viperidae , Animais , Viperidae/parasitologia , Helmintos/isolamento & purificação
4.
Materials (Basel) ; 16(3)2023 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-36770145

RESUMO

MXene is becoming a "rising star" material due to its versatility for a wide portfolio of applications, including electrochemical energy storage devices, electrocatalysis, sensors, biomedical applications, membranes, flexible and wearable devices, etc. As these applications promote increased interest in MXene research, summarizing the latest findings on this family of materials will help inform the scientific community. In this review, we first discuss the rapid evolutionary change in MXenes from the first reported M2XTx structure to the last reported M5X4Tx structure. The use of systematically modified synthesis routes, such as foreign atom intercalation, tuning precursor chemistry, etc., will be further discussed in the next section. Then, we review the applications of MXenes and their composites/hybrids for rapidly growing applications such as batteries, supercapacitors, electrocatalysts, sensors, biomedical, electromagnetic interference shielding, membranes, and flexible and wearable devices. More importantly, we notice that its excellent metallic conductivity with its hydrophilic nature distinguishes MXene from other materials, and its properties and applications can be further modified by surface functionalization. MXene composites/hybrids outperform pristine MXenes in many applications. In addition, a summary of the latest findings using MXene-based materials to overcome application-specific drawbacks is provided in the last few sections. We hope that the information provided in this review will help integrate lab-scale findings into commercially viable products.

5.
Artigo em Inglês | MEDLINE | ID: mdl-35386389

RESUMO

Introduction: Chronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide, corresponding to 5% of all deaths globally, with more than 90% occurring in low- and middle-income countries (LMIC). Pulmonary Rehabilitation (PR) is a routine clinical service for COPD management, often used in western countries. At present, there is no formal PR in Sri Lanka; a culturally appropriate programme is required that considers the views of adults living with COPD and healthcare providers (HCPs) who would be involved in the referral or delivery of PR. Purpose: The study assessed the attitudes and preferences of Sri Lankan adults living with COPD and attitudes and barriers of HCPs making PR referrals to inform an appropriate PR programme. Methodology: A descriptive cross-sectional study was conducted with the ethical clearance of Colombo south teaching hospital ERC committee (ERC Application No. 674), among adults living with COPD and HCPs in Colombo district, Sri Lanka. Adults living with COPD were enrolled August 2018-December 2018 using systematic random sampling from Colombo South Teaching Hospital and were assessed using a pre-tested interviewer administered questionnaire. HCPs were recruited from Colombo South Teaching Hospital and Jaffna Teaching Hospital between August 2018 and November 2018 and assessed using self-administered questionnaire. Results: Responses from 138 adults living with COPD (53% male, 52% aged ≥60 years) and 277 HCPs were collected. The majority of adults living with COPD were interested in participating in PR (80%) and would prefer PR to be delivered in a supervised, group-based, setting with hospital-based (49%). Adults living with COPD were mostly (73%) willing to spend between 30 minutes and 2 hours per day for PR-related activities. Among HCPs, 234 (83%) were nurses, 29 (11%) were hospital doctors and 14 (4%) were family physicians. The majority of HCPs stated that they were unsure about referring adults with COPD for PR (86%) and 61% stated considerable uncertainty regarding the availability of resources for PR. Nearly half of the HCPs (45%) felt they were not adequately prepared to refer adults living with COPD to PR programmes. Most HCPs (92%) reported that PR is worthwhile for COPD management. Conclusion: Adults living with COPD in Sri Lanka are willing to attend PR and would prefer group-based programmes delivered in hospitals, under the supervision of qualified personnel. Awareness about PR is poor and there is a lack of readiness to refer to PR amongst HCPs. There is an urgent need to train HCPs on PR and develop effective referral strategies to support PR uptake and delivery for adults living with COPD in Sri Lanka.


Assuntos
Doença Pulmonar Obstrutiva Crônica , Adulto , Estudos Transversais , Atenção à Saúde , Feminino , Pessoal de Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Doença Pulmonar Obstrutiva Crônica/reabilitação , Doença Pulmonar Obstrutiva Crônica/terapia , Sri Lanka
6.
J Biophotonics ; 15(6): e202100307, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35133076

RESUMO

This study uses infrared spectrometry coupled with data analysis techniques to understand colitis-induced alterations in the molecular components of serum samples. Using samples from 18 ulcerative colitis patients and 28 healthy volunteers, we assessed features such as absorbance values at wavenumbers of 1033 and 1076 cm-1 , and the ratios at 1121 versus 1020 cm-1 and 1629 versus 1737 cm-1 . Through the deconvolution of the amide I band, protein secondary structure analysis was performed. Colitis-induced alterations are reflected as fluctuations in the vibrational modes, and are used to identify associated spectral signatures. The results of the study show statistically significant differences in five identifying spectral signatures. Among them, the sensitivity and specificity of the spectral signature, I1121 /I1020 , were 100% and 86%, respectively. These findings resemble our earlier proof-of-concept investigations in mouse models and provide preliminary evidence that this could be a reliable diagnostic test for human patients.


Assuntos
Colite Ulcerativa , Colite , Animais , Biomarcadores , Colite Ulcerativa/diagnóstico , Humanos , Camundongos , Sensibilidade e Especificidade , Espectrofotometria Infravermelho
7.
Natl Sci Rev ; 8(3): nwaa134, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34691589

RESUMO

Climate change and increased urban population are two major concerns for society. Moving towards more sustainable energy solutions in the urban context by integrating renewable energy technologies supports decarbonizing the energy sector and climate change mitigation. A successful transition also needs adequate consideration of climate change including extreme events to ensure the reliable performance of energy systems in the long run. This review provides an overview of and insight into the progress achieved in the energy sector to adapt to climate change, focusing on the climate resilience of urban energy systems. The state-of-the-art methodology to assess impacts of climate change including extreme events and uncertainties on the design and performance of energy systems is described and discussed. Climate resilience is an emerging concept that is increasingly used to represent the durability and stable performance of energy systems against extreme climate events. However, it has not yet been adequately explored and widely used, as its definition has not been clearly articulated and assessment is mostly based on qualitative aspects. This study reveals that a major limitation in the state-of-the-art is the inadequacy of climate change adaptation approaches in designing and preparing urban energy systems to satisfactorily address plausible extreme climate events. Furthermore, the complexity of the climate and energy models and the mismatch between their temporal and spatial resolutions are the major limitations in linking these models. Therefore, few studies have focused on the design and operation of urban energy infrastructure in terms of climate resilience. Considering the occurrence of extreme climate events and increasing demand for implementing climate adaptation strategies, the study highlights the importance of improving energy system models to consider future climate variations including extreme events to identify climate resilient energy transition pathways.

8.
Micromachines (Basel) ; 12(9)2021 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-34577714

RESUMO

Infrared radiation (IR) was accidentally discovered in 1800 by the astronomer Sir William Herschel [...].

9.
Atten Percept Psychophys ; 83(5): 2281-2290, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33754299

RESUMO

Perception of the size of body parts, for instance the hand, has been shown to be distorted in healthy participants, with over- and underestimations of width and length, respectively. Illusory manipulations of body shape and size have highlighted the flexibility of the body representation and have also been found to update immediate perceptions of body size and surrounding objects. Here, we examined whether underlying misperceptions of hand width and length can be modified through exposure to illusory changes in hand size using a mirror visual feedback (MVF) paradigm. While questionnaire responses indicated subjective susceptibility to both magnified and minified manipulations, objective hand size estimates only showed significant differences following exposure to minifying mirrors. These variations might reflect differences in the way that stored representations are accessed or updated in response to size manipulations. Secondly, the findings further reinforce differences between subjective and objective outcomes of illusions on subsequent body perception.


Assuntos
Retroalimentação Sensorial , Ilusões , Imagem Corporal , Mãos , Voluntários Saudáveis , Humanos , Percepção Visual
10.
Electrophoresis ; 42(9-10): 1093-1101, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33665842

RESUMO

Electroporation is a promising method to inactivate cells and it has wide applications in medical science, biology and environmental health. Here, we investigate the bacteria inactivation performance of two different microfluidic electroporation devices with rhombus and circular micropillars used for generating locally enhanced electric field strength. Experiments are carried out to characterize the inactivation performance (i.e., the log removal efficiency) of two types of bacteria: Escherichia coli (E. coli, gram-negative) and Enterococcus faecalis (E. faecalis, gram-positive) in these two microfluidic devices. We find that under the same applied electric field, the device with rhombus micropillars performs better than the device with circular micropillars for both E. coli and E. faecalis. Numerical simulations show that due to the corner-induced singularity effect, the maximum electric field enhancement is higher in the device with rhombus micropillars than that in the device with circular micropillars. We also study the effects of DC and AC electric fields and flowrate. Our experiments demonstrate that the use of the DC field achieves higher log removal efficiencies than the use of AC field.


Assuntos
Microfluídica , Eletricidade , Eletroporação , Escherichia coli , Dispositivos Lab-On-A-Chip
11.
Biomed Opt Express ; 11(8): 4679-4694, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32923071

RESUMO

This study presents an application of infrared spectroscopy of sera for monitoring the efficacy of anti-TNFα therapy for inflammatory bowel diseases. Understanding the therapeutic response includes the analysis of absorption bands representing constituent molecules. Interleukin-10 knockout mouse model of the diseases with anti-TNFα treatment was used. The discrimination potential is optimized by analyzing data with curve fitting. It shows; antibody therapy markedly ameliorated the disease, concurring with earlier mucosal immunology and pathophysiologic studies. This technique may thus also be useful for the evaluation of mucosal healing or other therapeutic modalities of gastrointestinal tract diseases keeping the endoscopic tests as confirmatory.

12.
Cancers (Basel) ; 12(7)2020 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-32605072

RESUMO

Protein structural alterations, including misfolding and aggregation, are a hallmark of several diseases, including cancer. However, the possible clinical application of protein conformational analysis using infrared spectroscopy to detect cancer-associated structural changes in proteins has not been established yet. The present study investigates the applicability of Fourier transform infrared spectroscopy in distinguishing the sera of healthy individuals and breast cancer patients. The cancer-associated alterations in the protein structure were analyzed by fitting the amide I (1600-1700 cm-1) band of experimental curves, as well as by comparing the ratio of the absorbance values at the amide II and amide III bands, assigning those as the infrared spectral signatures. The snapshot of the breast cancer-associated alteration in circulating DNA and RNA was also evaluated by extending the spectral fitting protocol to the complex region of carbohydrates and nucleic acids, 1140-1000 cm-1. The sensitivity and specificity of these signatures, representing the ratio of the α-helix and ß-pleated sheet in proteins, were both 90%. Likewise, the ratio of amides II and amide III (I1556/I1295) had a sensitivity and specificity of 100% and 80%, respectively. Thus, infrared spectroscopy can serve as a powerful tool to understand the protein structural alterations besides distinguishing breast cancer and healthy serum samples.

13.
Micromachines (Basel) ; 11(6)2020 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-32481650

RESUMO

The use of multilayer semiconductor heterojunction structures has shown promise in infrared detector applications. Several heterostructures with innovative compositional and architectural designs have been displayed on emerging infrared technologies. In this review, we aim to illustrate the principles of heterostructure detectors for infrared detection and explore the recent progress on the development of detectors with the split-off band and threshold wavelength extension mechanism. This review article includes an understanding of the compositional and the architectural design of split-off band detectors and to prepare a database of their performances for the wavelength extension mechanism. Preparing a unique database of the compositional or architectural design of structures, their performance, and penetrating the basics of infrared detection mechanisms can lead to significant improvements in the quality of research. The brief outlook of the fundamentals of the infrared detection technique with its appropriateness and limitations for better performance is also provided. The results of the long-term study presented in this review article would be of considerable assistance to those who are focused on the heterostructure infrared detector development.

14.
Biomicrofluidics ; 14(1): 014103, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31933713

RESUMO

Microfluidic paper-based analytical devices (µPADs) represent a modest and feasible alternative for conventional analytical methods. However, the inadequate sensitivity of these devices limits the possible applications of µPADs. In this scenario, inducing ion concentration polarization (ICP) on µPADs has shown promise to overcome this limitation by preconcentrating the analytes of interest. Here, we report a µPAD implementing ICP using an off-shelf Nafion® membrane as the perm selective membrane. Two types of devices with a geometrical configuration of a straight channel converging at the middle connecting to circular reservoirs at the end of channels were fabricated. The devices are comprised of a single input channel and an absorption channel. The Nafion membrane is attached to the absorption channel of the device, which is encased by heating with paraffin films at both sides to lower the electro-osmotic flow generated by an applied DC electric field that is needed for ICP. The field induced ICP enables obtaining a maximum concentration factor of more than 2000 folds for fluorescein sodium salt solution on the µPAD. Also, since evaporation of the sample solution was reported to be of great influence on the concentration factor, we analyze the effect of sample solution evaporation on sample preconcentration. Furthermore, our reported fabrication method for µPAD can lower the fabrication cost down to 0.3 USD. This device shows the potential to be developed for serving as a diagnostic and environmental monitoring platform.

15.
Mater Today Proc ; 23(Pt 1): 43-48, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33718004

RESUMO

Performance of Dye-sensitized devices depends on the photon absorption and carrier injection properties of the sensitizer (dye). The orientation of the dye molecule affects the photon absorption cross-section, injection efficiency and carrier transport. These effects are studied, using three variants of cyanine dyes in n-TiO2/Dye/p-CuSCN heterojunction. The results show correlation of dye-molecule's orientation on the short-circuit-photocurrent (Isc). The open-circuit-voltage (Voc) is also subjective. The orientation of the dye molecule influence the photon-harvesting efficiency and obstruct the hole-conductor penetrating onto the working-electrode. Additionally, Cumulative effects of e-e, e-h, spin-coupling and HOMO/LUMO distribution are identified.

16.
Electrophoresis ; 41(10-11): 867-874, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-31667875

RESUMO

We report a microfluidic paper based analytical device implementing ion concentration polarization (ICP) for rapid pre-concentration of Escherichia coli in water. The fabricated device consists of a paper channel with a Nafion® membrane and in-built micro wire electrodes to supply electric voltage to induce the ICP effect. E. coli cells were stained with SYTO 9 and fluorescence was used as a sensing method. The device achieved high concentration factor up to 2 × 105 within minutes. The effect of total ion concentration, on ICP and fluorescence intensity was studied. The reported device and method are suitable and effective for detection of E. coli during ballast water quality monitoring, coastal water quality monitoring where high salinity water is present.


Assuntos
Escherichia coli/isolamento & purificação , Técnicas Analíticas Microfluídicas , Microbiologia da Água , Eletrodos , Desenho de Equipamento , Polímeros de Fluorcarboneto/química , Íons/química , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos , Papel , Cloreto de Sódio/química
17.
Sci Rep ; 9(1): 17756, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31780681

RESUMO

Standard and newly designed building blocks for complex urban sites- also designated by urban archetypes - are used in this study to quantify the influence of urban forms on their energy demand and energy systems design. An energy hub, which consists on a multi-carrier energy system involving multiple energy conversion, storage and/or network technologies, is employed to quantify the impact of the urban morphology on the energy system requirements. This study reveals that urban archetypes have a notable influence on the heating and cooling energy demands of city districts that can be characterized using form factors and floor area ratio. However, the influence on demand profiles cannot be assessed based on the aforementioned indicators. The cost of energy systems can increase up to 50% due to the impact of urban forms that are well beyond the increase of peak and/or annual energy demands. In addition, renewable energy integration to the grid as well its utilization in districts is influenced by urban forms. This makes it essential to consider energy system design as a part of the urban planning process moving even beyond building simulation.

18.
Phys Rev E ; 100(1-1): 010701, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31499900

RESUMO

The unique nanometer-sized helical structure in SmC_{α}^{*} may sometimes evolve continuously to the micrometer-sized one in SmC^{*}; conceivably ferroelectric SmC_{α}^{*} is to be unwound by an applied electric field. By drawing electric-field-induced birefringence contours in the field-temperature phase diagram and by studying the superlattice structure of the field-induced subphase with resonant x-ray scattering, we established that an applied field unexpectedly stabilizes the well-known antiferroelectric four-layer biaxial subphase as well as the other prototypal ferrielectric three-layer one in the SmC_{α}^{*} temperature range; the effective long-range interlayer interaction due to the discrete flexoelectric effect actually plays an important role in stabilizing not only the biaxial subphases but also the optically uniaxial SmC_{α}^{*} subphase, contrary to the notion that the competition between the direct interactions of the nearest-neighbor layers and those of the next-nearest-neighbor layers should be required for the nanometer-sized helical structure.

19.
Electrophoresis ; 40(18-19): 2522-2529, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31177580

RESUMO

Electroporation is a powerful tool for inactivating cells and transfecting biological cells and has applications in biology, genetic engineering, medicine, environment, and many others. We report a new continuous flow device embedded with insulating micropillars to achieve better performance of cell inactivation. The use of micropillars creates multiple electroporation zones with enhanced local electric field strengths. Using a model solution of Saccharomyces cerevisiae, we examined the inactivation performance of the device under various applied electric voltages and flow rates. Results from the numerical simulations and experiments showed that even with an induced transmembrane potential of 0.58 V, close to 63% of cell inactivation was achieved at a flow rate of 2.5 mL/h. This was higher than the 24% cell inactivation observed for a reference device without micropillars that was subjected to the same conditions.


Assuntos
Técnicas Citológicas/instrumentação , Eletroporação/instrumentação , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Citológicas/métodos , Eletroporação/métodos , Desenho de Equipamento , Técnicas Analíticas Microfluídicas/métodos , Saccharomyces cerevisiae/citologia
20.
Exp Brain Res ; 237(7): 1821-1832, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31079236

RESUMO

The rubber hand illusion (RHI) is a perceptual phenomenon in which participants experience ownership over a fake model hand through synchronous visuotactile stimulation. Several studies have shown that the illusion occurs only when both hands are in close proximity to each other. In the present study, we systematically examined the role of relative position (lateral, distal) and distance (13-75 cm) of the model hand (with respect to participants' real hand) on illusion experience across both lateral and distal positions. Furthermore, we also compared different facets of the subjective illusion experience; the experience of the model hand being part of one's body (i.e., ownership) and the perceptual fusion of vision and touch (i.e., referral of touch). In two experiments we observed indications for a stronger illusion experiences in distal compared to lateral positions of identical distances, indicating that the illusory effects may vary as a function of the relative position of the hand. Our results also showed that manipulations of distance differently modulated both facets of the illusion. While ownership was restricted to near distances, referral of touch sensations remained stable at farther distances. These results are interpreted in relation to variations in sensory weighting across different planes.


Assuntos
Percepção de Distância/fisiologia , Mãos/fisiologia , Ilusões/fisiologia , Estimulação Luminosa/métodos , Propriocepção/fisiologia , Percepção do Tato/fisiologia , Feminino , Humanos , Ilusões/psicologia , Masculino , Distribuição Aleatória , Percepção Espacial/fisiologia , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...