Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 81
Filtrar
1.
RSC Adv ; 14(14): 10120-10130, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38566837

RESUMO

Hybrid supercapacitors can produce extraordinary advances in specific power and energy to display better electrochemical performance and better cyclic stability. Amalgamating metal oxides with metal-organic frameworks endows the prepared composites with unique properties and advantageous possibilities for enhancing the electrochemical capabilities. The present study focused on the synergistic effects of the CuCo(5-NIPA)-Nd2O3 composite. Employing a half-cell configuration, we conducted a comprehensive electrochemical analysis of CuCo(5-NIPA), Nd2O3, and their composite. Owing to the best performance of the composite, the hybrid device prepared from CuCo(5-NIPA)-Nd2O3 and activated carbon demonstrated a specific capacity of 467.5 C g-1 at a scan rate of 3 mV s-1, as well as a phenomenal energy and power density of 109.68 W h kg-1 and 4507 W kg-1, respectively. Afterwards, semi-empirical techniques and models were used to investigate the capacitive and diffusive mechanisms, providing important insights into the unique properties of battery-supercapacitor hybrids. These findings highlight the enhanced performance of the CuCo(5-NIPA)-Nd2O3 composite, establishing it as a unique and intriguing candidate for applications requiring the merging of battery and supercapacitor technologies.

2.
Nature ; 628(8008): 527-533, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38600389

RESUMO

Topology1-3 and interactions are foundational concepts in the modern understanding of quantum matter. Their nexus yields three important research directions: (1) the competition between distinct interactions, as in several intertwined phases, (2) the interplay between interactions and topology that drives the phenomena in twisted layered materials and topological magnets, and (3) the coalescence of several topological orders to generate distinct novel phases. The first two examples have grown into major areas of research, although the last example remains mostly unexplored, mainly because of the lack of a material platform for experimental studies. Here, using tunnelling microscopy, photoemission spectroscopy and a theoretical analysis, we unveil a 'hybrid' topological phase of matter in the simple elemental-solid arsenic. Through a unique bulk-surface-edge correspondence, we uncover that arsenic features a conjoined strong and higher-order topology that stabilizes a hybrid topological phase. Although momentum-space spectroscopy measurements show signs of topological surface states, real-space microscopy measurements unravel a unique geometry of topologically induced step-edge conduction channels revealed on various natural nanostructures on the surface. Using theoretical models, we show that the existence of gapless step-edge states in arsenic relies on the simultaneous presence of both a non-trivial strong Z2 invariant and a non-trivial higher-order topological invariant, which provide experimental evidence for hybrid topology. Our study highlights pathways for exploring the interplay of different band topologies and harnessing the associated topological conduction channels in engineered quantum or nano-devices.

3.
Heliyon ; 10(4): e25609, 2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38375273

RESUMO

Climate change alters the climate condition and ocean environment, leading to accelerated coastal erosion and a shift in the coastline shape. From previous studies, Southeast Asia's coastal region is suffering from severe coastal erosion. It is most sensitive and vulnerable to climate change, has broad and densely populated coastlines, and is under ecological pressure. Efforts to systematically review these studies are still insufficient despite many studies on the climate change linked to coastal erosion, the correlation between coastal erosion and coastal communities, and the adaptative measures to address these issues and their effectiveness in Southeast Asia. Therefore, by analyzing the existing literature, the purpose of this review was to bridge the knowledge gap and identify the link between climate change and coastal erosion in Southeast Asia in terms of sea-level rise, storm surge, and monsoon patterns. The RepOrting standards for Systematic Evidence Syntheses (ROSES) guided the study protocol, including articles from the Scopus and Dimension databases. There were five main themes considered: 1) climate change impact, 2) contributing factors to coastal erosion, 3) coastal erosion impact on coastal communities, 4) adaptation measure and 5) effectiveness of adaptation measure using thematical analysis. Subsequently, nine sub-themes were produced from the themes. Generally, in Southeast Asia, coastal erosion was reflected by the rising sea level. Throughout reviewing past literature, an interesting result was explored. Storm surges also had the potential to affect coastal erosion due to alterations of the atmospheric system and seasonal monsoon as the result of climate change. Meanwhile, an assessment of current erosion control strategies in relation to the relative hydrodynamic trend was required to avoid the failure of defence structures and the resulting danger to coastal communities. Systematically reviewing the existing literature was critical, hence it could significantly contribute to the body of knowledge. It provides valuable information for interested parties, such as authorities, the public, researchers, and environmentalists, while comprehending existing adaptation practices. This kind of review could strategize adaptation and natural resource management in line with coastal communities' needs, abilities, and capabilities in response to environmental and other change forms.

4.
RSC Adv ; 14(3): 1655-1664, 2024 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-38187454

RESUMO

The development of electrode materials with extraordinary energy densities or high power densities has experienced a spectacular upsurge because of significant advances in energy storage technology. In recent years, the family of metal-organic frameworks (MOFs) has become an essential contender for electrode materials. Herein, two cobalt-based MOFs are synthesized with distinct linkers named 1,2,4,5-benzene-tetra-carboxylic acid (BTCA) and 1,2,3,4-cyclopentane-tetracarboxylic acid (CPTC). Investigations have been rigorously conducted to fully understand the effect of linkers on the electrochemical properties of Co-based MOFs. The best sample among the MOFs was used with activated carbon to create a battery-supercapacitor hybrid device. Due to its noteworthy results, specific capacity (100.3 C g-1), energy density (23 W h kg-1), power density (3400 W kg-1) and with the lowest ESR value of 0.4 Ω as well as its 95.4% capacity retention, the fabricated hybrid device was discovered to be very appealing for applications demanding energy storage. An approach for evaluating battery-supercapacitors was employed by quantifying the capacitive and diffusive contributions using Dunn's model to reflect the bulk and surface processes occurring during charge storage. This study fills the gap between supercapacitors and batteries, as well as providing a roadmap for creating a new generation of energy storage technologies with improved features.

5.
RSC Adv ; 14(4): 2205-2213, 2024 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-38213966

RESUMO

Efficient energy storage and conversion is crucial for a sustainable society. Battery-supercapacitor hybrid energy storage devices offer a promising solution, bridging the gap between traditional batteries and supercapacitors. In this regard, metal-organic frameworks (MOFs) have emerged as the most versatile functional compounds owing to their captivating structural features, unique properties, and extensive diversity of applications in energy storage. MOF properties are governed by the structure and topological characteristics, which are influenced by the types of ligands and metal nodes. Herein, MOFs based on pyridine 3,5-dicarboxylate (PYDC) ligand in combination with copper and cobalt are electrochemically analyzed. Owing to the promising initial characterization of Cu-PYDC-MOF, a battery supercapacitor hybrid device was fabricated, comprising Cu-PYDC-MOF and activated carbon (AC) electrodes. The device showcased energy and power density of 17 W h kg -1 and 2550 W kg -1, respectively. Dunn's model was employed to gain deeper insights into the capacitive and diffusive contributions of the device. With their performance and versatility, the PYDC-based MOFs stand at the forefront of energy technology, ready to power a brighter future for upcoming generations.

6.
Environ Sci Pollut Res Int ; 31(10): 15339-15347, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38294656

RESUMO

Soil contaminated with heavy metals cause serious threat to the soil quality, biota, and human. The removal or stabilization of heavy metals through plants is an environment friendly approach. The aim of study was to assess the potential of Celosia argentea L. for the phytoremediation of heavy metals contaminated soil. Soil was spiked with different levels (0, 100, 200, 300, and 400 mg/kg) of chromium (Cr), copper (Cu), lead (Pb), and Zn (Zn). Experiment was carried out in greenhouse and impact of heavy metals was evaluated on plant by assessing the germination rate and plant growth. To evaluate either plant has potential to extract/stabilize the heavy metals, concentration in roots and shoot, translocation factor (TF), bioconcentration factor (BCF), and bioaccumulation factor (BAF) were determined. Application of heavy metals significantly affected the germination rate and minimum (26.6%) was observed in Cr spiked soil (400 mg/kg). Moreover, the biomass of C. argentea was also affected by the application of heavy metals. However, the concentration of heavy metals in roots and shoots were low. The BCF and BAF of C. argentea was lower than 1 except at lower levels of Pb and Zn, but the TF was greater than 1. The TF showed that plants have capability to transfer heavy metals to shoots once they are taken up by roots. However, based on the BCF and concentrations of heavy metals in shoots, it is evident that plant could play important role in the phytostabilization of heavy metals polluted soil.


Assuntos
Celosia , Metais Pesados , Poluentes do Solo , Humanos , Biodegradação Ambiental , Solo , Chumbo , Poluentes do Solo/análise , Metais Pesados/análise , Cromo , Plantas
7.
Parasitol Res ; 123(1): 5, 2023 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-38052938

RESUMO

Cutaneous Leishmaniasis is endemic in the tribal district of Khyber near the Pak-Afghan border and is caused by Leishmania tropica. In Pakistan, cutaneous leishmaniasis caused by L. tropica is considered anthroponotic and is thought to be maintained by a human-sand fly-human transmission cycle. Along with humans, other mammals may also be acting as reservoir hosts of leishmaniasis in the study area. To investigate the role of non-human mammals in the transmission of leishmaniasis, blood samples were collected from 245 animals from the CL endemic district of Khyber, Pakistan. Leishmania parasite in these samples was detected by amplifying the species-specific sequences in minicircle kinetoplast DNA, using PCR. L. tropica DNA was detected in 18 (7.35%) samples, comprising 11 cows (Bos taurus), 6 goats (Capra hircus), and 1 dog (Canus lupus familiaris). Only a single cow and dog had a leishmaniasis-like lesion, and the remaining positive samples were asymptomatic. None of the tested sheep (Ovis aries) and rat (Rattus rattus, Rattus norvegicus) was positive. The present study reports the first instance of molecular detection of L. tropica in domestic animals. Our study indicates that along with humans' cows, goats and dogs may also be playing an important role in the transmission of anthroponotic cutaneous leishmaniasis in district Khyber in particular and Pakistan in general.


Assuntos
Leishmania tropica , Leishmaniose Cutânea , Feminino , Humanos , Animais , Ratos , Bovinos , Cães , Ovinos , Leishmania tropica/genética , Paquistão/epidemiologia , Leishmaniose Cutânea/epidemiologia , Leishmaniose Cutânea/veterinária , Leishmaniose Cutânea/diagnóstico , Animais Domésticos , Cabras
8.
Cureus ; 15(11): e48725, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38046753

RESUMO

BACKGROUND: Peak flow is a crucial but simple test used to categorize the severity of an episode of an acute exacerbation of asthma. It should be regularly done in all the patients who present with asthma acute exacerbation in the emergency department. The British Thoracic Society (BTS)/Scottish Intercollegiate Guidelines Network (SIGN) guidelines stipulate peak flow use as one of the main tools to categorize acute asthma into moderate, severe, and life-threatening asthma. The BTS and SIGN guidelines also state peak flow is to be utilized in monitoring the disease and to guide in treating patients with acute asthma. METHODS AND MATERIALS: This study aims to identify the adherence to BTS/SIGN guidelines around the use of peak expiratory flow rate (PEFR) in assessing the severity of patients presenting with acute exacerbation of asthma in a district general hospital. The retrospective cohort study involved collating data between October 2022 and February 2023 from our hospital electronic system. The data collected about the use of PEFR and whether the patients were being classified by severity in presentation following this was compared to the BTS/SIGN 158 asthma guidelines. Following this, the data analysis was done using IBM SPSS Statistics for Windows, Version 21.0 (Released 2012; IBM Corp., Armonk, New York, United States). RESULTS: Data from 92 patients were collated. PEFR was recorded for 29.3% (n=27) of patients and acute exacerbation of asthma severity was documented in merely 17.4% (n=16) patients. CONCLUSION: The results indicate a significant proportion of the patient cohort analyzed did not have peak flow readings, there is clear room for improvement, and further intervention is needed in order for the department to adhere to the gold standard guidelines (i.e., BTS/SIGN 158), and thus improve the management and monitoring of acute asthma exacerbations. Future directions can include departmental education, posters as a reminder, and prompts on the electronic system used to alert users to check PEFR when a diagnosis of acute asthma exacerbation is documented.

9.
RSC Adv ; 13(47): 32918-32926, 2023 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-38025850

RESUMO

The increasing levels of carbon dioxide (CO2) in the atmosphere may dissolve into the ocean and affect the marine ecosystem. It is crucial to determine the level of dissolved CO2 in the ocean to enable suitable mitigation actions to be carried out. The conventional electrode materials are expensive and susceptible to chloride ion attack. Therefore, there is a need to find suitable alternative materials. This novel study investigates the electrochemical behaviour of dissolved CO2 on roughened molybdenum (Mo) microdisk electrodes, which were mechanically polished using silicon carbide paper. Pits and dents can be seen on the electrode surface as observed using scanning electron microscopy. X-ray diffraction spectra confirm the absence of abrasive materials and the presence of defects on the electrode surface. The electrochemical surface for the roughened electrodes is higher than that for the smoothened electrodes. Our findings show that the roughened electrodes exhibit a significantly higher electrocatalytic activity than the smoothened electrodes for the reduction of dissolved CO2. Our results reveal a linear relationship between the current and square root of scan rate. Furthermore, we demonstrate that saturating the electrolyte solution with CO2 using a bubbling time of just 20 minutes at a flow rate of 5 L min-1 for a 50 mL solution is sufficient. This study provides new insights into the electrochemical behaviour of dissolved CO2 on roughened Mo microdisk electrodes and highlights their potential as a promising material for CO2 reduction and other electrochemical applications. Ultimately, our work contributes to the ongoing efforts to mitigate the effects of climate change and move towards a sustainable future.

10.
Environ Monit Assess ; 195(12): 1474, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37964088

RESUMO

Climate factors like temperature, precipitation, humidity, and sunshine time exert a profound influence on vegetation. The intricate interplay between the two is crucial to understand in the face of changing climate to develop mitigation strategies. In the current exploration, we delve how climate variability (CV) has impacted the vegetation in the Peshawar Basin (PB) using remote sensing data tools. The trend of climatic variability was investigated using the modified Mann-Kendall test and Sen's slope statistics. The changing climatic parameters were regressed on the Moderate Resolution Imaging Spectroradiometer (MODIS) normalized difference vegetation index (NDVI). The NDVI was further analyzed for spatiotemporal variability under land surface temperature (LST) influence. Results revealed that among the climate factors, average annual temperature and solar radiation have a significant (p < 0.05) negative impact on vegetation while precipitation and relative humidity significantly (p < 0.05) influence NDVI positively. The overall positive trend shows that vegetation improved between 2001 and 2020 with time, however some years (2010, 2012, 2014, 2016, and 2017) with low NDVI. NDVI varied in space considerably due to climatic extremes brought on by CV and the urbanization of agricultural land. NDVI regressed on LST showed that there was no or very little vegetation in the grids with high LST. The study concluded that the region is significantly impacted by both CV-related extreme weather events and anthropogenic activities. The vegetation is improving, but it is in danger of being destroyed by deforestation due to CV and human activities that exacerbate the risk of future calamities. To protect vegetation and avoid disasters, there is an immense need for adaptation and mitigation measures to deal with the region's fast-changing environment. The study urges local authorities to create climate-resilient governmental policies and supports regional sustainable development and vegetation restoration.


Assuntos
Mudança Climática , Monitoramento Ambiental , Humanos , Imagens de Satélites , Temperatura , Agricultura , China
11.
Nanoscale ; 15(43): 17249-17269, 2023 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-37859601

RESUMO

Dye-sensitized solar cells (DSSCs) have attracted much attention as promising tools in renewable energy conversion technology. This is mainly because of their beneficial qualities, such as their impressive efficiency levels and low-cost fabrication techniques. An overview of MXene-modified electrodes in DSSCs is given in this review article. MXenes are two-dimensional (2D) transition metal carbides or nitrides with remarkable properties such as high conductivity and large surface area. MXenes' properties make them an appealing material for various applications, including energy storage, catalysis, and electronic devices. MXene integration enhances ion transport, dye adsorption, and charge transport in DSSC electrodes. In-depth analysis of the use of 2D Mxene and integration with carbon nanotubes (CNTs), reduced graphene oxide (rGO), 2D MoS2, and hybrids like 2D-2D heterostructures for electrode modification in photovoltaics (PVs), including anodes, photoanodes, composite decorated electrodes, counter electrodes (CEs), and electrolytes, is provided in this review article. The effects on the performance metrics of various deposition techniques are discussed and assessed. The use of MXene-modified electrodes in DSSCs suggests potential for enhancing the performance and efficiency of these solar cells in general. The article examines this strategy's potential advantages and implications, illuminating the fascinating advancements in the area and emphasizing MXenes' potential as a valuable substance for renewable energy applications. We also discuss the difficulties and potential benefits of using MXene-modified electrodes in DSSCs and emphasize the need for additional study to enhance stability, optimize MXene integration techniques, and enhance long-term device performance. The scalability and potential of MXene-based electrode modifications for commercial applications are also covered, addressing issues and prospects for the future, focusing on the necessity of more study. Electrodes modified with MXenes can improve DSSC performance and advance sustainable energy conversion.

12.
ACS Nano ; 17(18): 17884-17896, 2023 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-37656985

RESUMO

In future solar cell technologies, the thermodynamic Shockley-Queisser limit for solar-to-current conversion in traditional p-n junctions could potentially be overcome with a bulk photovoltaic effect by creating an inversion broken symmetry in piezoelectric or ferroelectric materials. Here, we unveiled mechanical distortion-induced bulk photovoltaic behavior in a two-dimensional (2D) material, MoTe2, caused by the phase transition and broken inversion symmetry in MoTe2. The phase transition from single-crystalline semiconducting 2H-MoTe2 to semimetallic 1T'-MoTe2 was confirmed using X-ray photoelectron spectroscopy (XPS). We used a micrometer-scale system to measure the absorption of energy, which reduced from 800 to 63 meV during phase transformation from hexagonal to distorted octahedral and revealed a smaller bandgap semimetallic behavior. Experimentally, a large bulk photovoltaic response is anticipated with the maximum photovoltage VOC = 16 mV and a positive signal of the ISC = 60 µA (400 nm, 90.4 Wcm-2) in the absence of an external electric field. The maximum values of both R and EQE were found to be 98 mAW-1 and 30%, respectively. Our findings are distinctive features of the photocurrent responses caused by in-plane polarity and its potential from a wide pool of established TMD-based nanomaterials and a cutting-edge approach to optimize the efficiency in converting photons-to-electricity for power harvesting optoelectronics devices.

13.
Bot Stud ; 64(1): 25, 2023 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-37716923

RESUMO

BACKGROUND: The present study was conducted to explore the diversity pattern of spring vegetation under the influence of topographic and edaphic variables in sub-tropical zone, District Malakand. In the present vegetation study, 252 species of 80 families were recorded in the study area. It included 39 species of trees, 43 species of shrubs, 167 species of herbs and 3 climber species. As a whole, 12 communities were established on the basis of topographic and edaphic characteristics in 12 different stations. RESULTS: The results of the present study revealed that all diversity indices (species diversity, evenness index, species richness index, maturity index) during spring showed that the communities in plains lying at lower altitudes had higher diversity while the communities formed at high altitudes had lower diversity. The results of the similarity index showed that there was low similarity (below 50%) amongst the communities in different stations. CONCLUSIONS: It can be concluded that variations in topographic and edaphic factors affect species diversity and communities pattern.

14.
ACS Omega ; 8(25): 22788-22808, 2023 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-37396236

RESUMO

Drought and osmotic stresses are major threats to agricultural crops as they affect plants during their life cycle. The seeds are more susceptible to these stresses during germination and establishment of seedlings. To cope with these abiotic stresses, various seed priming techniques have broadly been used. The present study aimed to assess seed priming techniques under osmotic stress. Osmo-priming with chitosan (1 and 2%), hydro-priming with distilled water, and thermo-priming at 4 °C were used on the physiology and agronomy of Zea mays L. under polyethylene glycol (PEG-4000)-induced osmotic stress (-0.2 and -0.4 MPa). The vegetative response, osmolyte content, and antioxidant enzymes of two varieties (Pearl and Sargodha 2002 White) were studied under induced osmotic stress. The results showed that seed germination and seedling growth were inhibited under osmotic stress and germination percentage, and the seed vigor index was enhanced in both varieties of Z. mays L. with chitosan osmo-priming. Osmo-priming with chitosan and hydro-priming with distilled water modulated the level of photosynthetic pigments and proline, which were reduced under induced osmotic stress; moreover, the activities of antioxidant enzymes were improved significantly. In conclusion, osmotic stress adversely affects the growth and physiological attributes; on the contrary, seed priming ameliorated the stress tolerance resistance of Z. mays L. cultivars to PEG-induced osmotic stress by activating the natural antioxidation enzymatic system and accumulating osmolytes.

15.
Small ; 19(48): e2305059, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37507833

RESUMO

Electrochemical energy storage devices run on two fundamentally different processes: charge storage across the double layer and redox reactions. A satisfactory understanding of the underlying mechanism is only possible once the two contributions are deconvoluted. The b-value and the ν -ν1/2 model are two familiar steps undertaken to separate these contributions but as it is shown here both metrics are flawed, prone to misinterpretation, frequently invoked without attention to their limitations, and in need of re-examination. After exploring these flaws through the lens of a diverse set of cyclic voltammetry data we opine that use of the b-value be discouraged on account of subjectivity inherent to the metric, and the ν -ν1/2 model be replaced by the one proposed here. This new model ultimately reduces the root mean square error significantly and provides a robust tool for the evaluation of energy storage devices.

16.
RSC Adv ; 13(33): 22936-22944, 2023 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-37520089

RESUMO

In the pursuit of developing superior energy storage devices, an integrated approach has been advocated to harness the desirable features of both batteries and supercapacitors, particularly their high energy density, and high-power density. Consequently, the emergence of hybrid supercapacitors has become a subject of increasing interest, as they offer the potential to merge the complementary attributes of these two technologies into a single device, thereby surpassing the limitations of conventional energy storage systems. In this context the Metal-Organic Frameworks (MOFs), consisting of metal centers and organic linkers, have emerged as highly trending materials for energy storage by virtue of their high porosity. Here, we investigate the electrochemical performance of cobalt-pyridine-3,5-di-carboxylate-MOF (Co-PDC-MOF) and cobalt-1,2,3,4-cyclopentane tetra-carboxylate-MOF (Co-CPTC-MOF). In the setup involving the analysis of Co-PDC-MOF and Co-CPTC-MOF materials, a configuration comprising three electrodes was utilized. Drawing upon the promising initial properties of CPTC, a battery device was fabricated, comprising Co-CPTC-MOF, and activated carbon (AC) electrodes. Retaining a reversible capacity of 97% the device showcased impressive energy and power density of 20.7 W h g-1 and 2608.5 W kg-1, respectively. Dunn's model was employed, to gain deeper insights into the capacitive and diffusive contributions of the device.

17.
Molecules ; 28(13)2023 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-37446722

RESUMO

Plants are sessile and mostly exposed to various environmental stresses which hamper plant growth, development, and significantly decline its production. Drought stress is considered to be one of the most significant limiting factors for crop plants, notably in arid and semi-arid parts the world. Therefore, the present study aimed to evaluate the potential impact of different concentrations (10, 100, and 200 µg/mL) of kinetin capped zinc oxide nanoparticles (Kn-ZnONPs) on Vigna radiata (L.) R. Wilczek under varying levels (5%, 10%, 15%) of PEG-induced drought stress. ZnONPs were synthesized by a co-precipitation method using Zinc acetate as a precursor at pH-12, incinerated to 500 °C, and kinetin was used as a surface functionalizing agent. The resulting Kn-ZnONPs were characterized by various contemporary analytical techniques, including SEM, SEM-EDS, XRD, DLS, and Zeta potential and IR spectroscopy. Crystalline Kn-ZnONPs, with a zeta potential of 27.8 mV and a size of 67.78 nm, of hexagonal wurtzite structure and vibrational stretches associated with N-H, C-O, C-N, etc., were confirmed. PEG-induced drought stress significantly reduced the growth of V. radiata by declining the chlorophyll and carotenoid contents. Moreover, a significant decrease in the levels of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), soluble sugar contents, proline, protein contents, phenol, and tannin were observed compared to the control. However, the exogenous application of Kn-ZnONPs ameliorated all photosynthetic parameters by up-regulating the antioxidant defense system through the promotion of SOD, POD, CAT, and lipid peroxidation levels. The biochemical parameters, such as proteins, soluble sugars, and proline, were observed to be maximum in plants treated with 200 µg/mL Kn-ZnONPs under 5% drought stress. The application of Kn-ZnONPs also enhanced the total phenol contents, flavonoid, and tannin contents. In conclusion, the findings of this study demonstrate that the exogenous application of Kn-ZnONPs provides beneficial effects to V. radiata by attenuating the damaging effects of drought stress through the up-regulation of the antioxidant defense system and osmolytes. These results suggest that Kn-ZnONPs have potential as a novel approach to improve crop productivity under drought stress conditions.


Assuntos
Fabaceae , Nanopartículas , Vigna , Óxido de Zinco , Antioxidantes/farmacologia , Vigna/metabolismo , Cinetina/farmacologia , Óxido de Zinco/farmacologia , Secas , Fabaceae/metabolismo , Peroxidases/metabolismo , Superóxido Dismutase/metabolismo , Peroxidase/metabolismo , Prolina/metabolismo
18.
RSC Adv ; 13(26): 18038-18044, 2023 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-37323445

RESUMO

Transition metal dichalcogenides (TMDCs) have been explored in recent years to utilize in electronics due to their remarkable properties. This study reports the enhanced energy storage performance of tungsten disulfide (WS2) by introducing the conductive interfacial layer of Ag between the substrate and active material (WS2). The interfacial layers and WS2 were deposited through a binder free method of magnetron sputtering and three different prepared samples (WS2 and Ag-WS2) were scrutinize via electrochemical measurements. A hybrid supercapacitor was fabricated using Ag-WS2 and activated carbon (AC) since Ag-WS2 was observed to be the most proficient of all three samples. The Ag-WS2//AC devices have attained a specific capacity (Qs) of 224 C g-1, while delivering the maximum specific energy (Es) and specific power (Ps) of 50 W h kg-1 and 4003 W kg-1, respectively. The device was found to be stable enough as it retains 89% capacity and 97% coulombic efficiency after 1000 cycles. Additionally, the capacitive and diffusive currents were obtained through Dunn's model to observe the underlying charging phenomenon at each scan rate.

19.
RSC Adv ; 13(23): 15575-15585, 2023 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-37228682

RESUMO

The layered structures of tungsten disulfide (WS2) and molybdenum tungsten disulfide (MoWS2) are considered as the most promising electrode materials for energy storage devices. Herein, MS (magnetron sputtering) is required for the deposition of WS2 and MoWS2 on the surface of the current collector to attain an optimized layer thickness. The structural morphology and topological behavior of the sputtered material were examined via X-ray diffraction and atomic force microscopy. Three-electrode assembly was used to start the electrochemical investigations to identify the most optimal and effective sample among WS2 and MoWS2. CV (cyclic voltammetry), GCD (galvanostatic charging discharging), and EIS (electro-impedance spectroscopy) techniques were employed to analyze the samples. After preparing WS2 with optimized thickness as the superior performing sample, a hybrid device was designed as WS2//AC (activated carbon). With a remarkable cyclic stability of 97% after 3000 continuous cycles, the hybrid supercapacitor generated a maximum energy density (Es) value of 42.5 W h kg-1 and 4250 W kg-1 of power density (Ps). Besides, the capacitive and diffusive contribution during the charge-discharge process and b-values were calculated by Dunn's model, which lay in the 0.5-1.0 range and the fabricated WS2 hybrid device was found to have a hybrid nature. The outstanding outcomes of WS2//AC make it suitable for future energy storage applications.

20.
J Phys Condens Matter ; 35(30)2023 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-37072005

RESUMO

Raman scattering (RS) in bulk hafnium disulfide (HfS2) is investigated as a function of temperature (5 K - 350 K) with polarization resolution and excitation of several laser energies. An unexpected temperature dependence of the energies of the main Raman-active (A1gand Eg) modes with the temperature-induced blueshift in the low-temperature limit is observed. The low-temperature quenching of a modeω1(134 cm-1) and the emergence of a new mode at approx. 184 cm-1, labeledZ, is reported. The optical anisotropy of the RS inHfS2is also reported, which is highly susceptible to the excitation energy. The apparent quenching of the A1gmode atT = 5 K and of the Egmode atT= 300 K in the RS spectrum excited with 3.06 eV excitation is also observed. We discuss the results in the context of possible resonant character of light-phonon interactions. Analyzed is also a possible effect of the iodine molecules intercalated in the van der Waals gaps between neighboringHfS2layers, which inevitably result from the growth procedure.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA