Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 44
Filtrar
1.
Phys Chem Chem Phys ; 26(24): 17191-17204, 2024 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-38853749

RESUMEN

Structural symmetry breaking plays a pivotal role in fine-tuning the properties of nano-layered materials. Here, based on the first-principles approaches we propose a Janus monolayer of metallic CoSb by breaking the out-of-plane structural symmetry. Specifically, within the CoSb monolayer by replacing the top-layer 'Sb' with 'As' atoms entirely, the Janus Co2AsSb monolayer can be formed, whose structure is confirmed via structural optimization and ab initio molecular dynamics simulations. Notably, the Janus Co2AsSb monolayer demonstrates stability at an elevated temperature of 1200 K, surpassing the stability of the CoSb monolayer, which remains stable only up to 900 K. We propose that both the CoSb and Janus Co2AsSb monolayers could serve as capable anode materials for power-driven metal-ion batteries, owing to their substantial theoretical capacity and robust binding strength. The theoretical specific capacities for Li/Na reach up to 1038.28/1186.60 mA h g-1 for CoSb, while Janus Co2AsSb demonstrates a marked improvement in electrochemical storage capacity of 3578.69/2215.38 mA h g-1 for Li/Na, representing a significant leap forward in this domain. The symmetry-breaking effect upgrades the CoSb monolayer, as a more viable contender for power-driven metal-ion batteries. Furthermore, electronic structure calculations indicate a notable charge transfer that augments the metallic nature, which would boost electrical conductivity. These simulations demonstrate that the CoSb and Janus Co2AsSb monolayers have immense potential for application in the design of metal-ion battery technologies.

2.
ACS Appl Mater Interfaces ; 16(4): 4836-4846, 2024 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-38234104

RESUMEN

Transition-metal dichalcogenide WSe2 has attracted increasing interest due to its large thermopower (S), low-cost, and environment-friendly constituents. However, its thermoelectric figure of merit, ZT, of WSe2 is limited due to its large lattice thermal conductivity (κL) and low electrical conductivity. In view of WSe2 and MoS2 having the same crystal structure, here we designed and prepared Nb-doped quarternary mixed crystal (MC) Nb0.05W0.95-xMox(Se1-xSx)2 (0 ≤ x ≤ 0.095). The results indicate that the κL of the MC can reach as low as 0.12 W m K-1 at 850 K, being 93% smaller than that of WSe2. Our analysis reveals that its low κL originates chiefly from intense scattering of both high-frequency phonons from point defects (mainly alloying elements) and mid/low-frequency phonons from MoS2 inclusions residual within MC. In addition, the alloying of WSe2 with MoS2 causes a 5-fold increase in cation vacancies (VW‴'), leading to a large increase in hole concentration and electrical conductivity, which gives rise to a ∼7.5 times increase in power factor (reaching 4.2 µ W cm-1 K-2 at 850 K). As a result, a record high ZTmax = 0.63 is achieved at 850 K for the MC sample with x = 0.076, which is 20 times larger than that of WSe2, demonstrating that MC Nb0.05W0.95-xMox(Se1-xSx)2 is a promising thermoelectric material.

3.
Phys Chem Chem Phys ; 25(43): 29585-29593, 2023 Nov 08.
Artículo en Inglés | MEDLINE | ID: mdl-37877302

RESUMEN

Tetradymite compounds, such as Bi2Te3, crystallizing in rhombohedral structures have triggered tremendous research interest from the scientific community because of their intriguing properties. Herein, using the state-of-the-art first-principles calculations, we identify that La2X2Y (X = I, Br, Cl; Y = Ge, Te) nanosheets exhibit a ternary tetradymite-type structure with extraordinary electrical and electrochemical properties. It is first demonstrated that the layered La2X2Y compounds exhibit weak interlayer coupling with cleavage energies in the range of ∼0.28-0.38 J m-2, allowing the ready separation of monolayers that can be synthesized by mechanical exfoliation from their bulk counterparts. Next, we predict that La2X2Ge nanosheets exhibit a semiconducting nature, and upon physical realistic strain, a Dirac cone can be realized. These findings can be exploited in the transport properties. Furthermore, we comprehensively investigated the electrochemical properties of the predicted systems to evaluate their potential use in metal-ion (Li/Na) batteries. Our detailed analyses reveal that the Li (Na) adatoms are sufficiently mobile on the surface of the studied systems. For instance, the binding energy for the Li (Na) adatom on La2I2Ge is -2.24(-1.79) eV with a diffusion barrier of as small as ∼0.31(0.20) eV. Subsequently, the maximum theoretical specific capacity for Li (Na) reaches as high as 887(1064) mA h g-1, which can be attributed to a much higher storage capacity compared to previously identified 2D anode materials. These findings substantiate that the predicted nanosheets could be synthesized to explore their potential applications in future metal-ion batteries.

4.
J Phys Condens Matter ; 36(6)2023 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-37903432

RESUMEN

Black phosphorene (BP) is a glowing two-dimensional semiconducting layer material for cutting-edge microelectronics, with high carrier mobility and thickness-dependent band gap. Here, based on van der Waals (vdW)-corrected first-principles approaches, we investigated stacked BP/tin selenide (BP/SnSe) vdW heterostructure as an anode material for metal ion batteries, which exhibits a significant theoretical capacity, along with relatively durable binding strength compared to the constituent BP and SnSe monolayers. Our calculations demonstrated that the Li/Na adatom favors insertion into the interlayer region of BP/SnSe vdW heterostructure owing to synergistic interfacial effect, resulting in comparable diffusivity to the BP and SnSe monolayers. Subsequently, the theoretical specific capacities for Li/Na are found to be as high as 956.30 mAhg-1and 828.79 mAhg-1, respectively, which could be attributed to the much higher storage capacity of Li/Na adatoms in the BP/SnSe vdW heterostructure. Moreover, the electronic structure calculations reveal that a large amount of charge transfer assists in semiconductor-to-metallic transition upon lithiation/sodiation, ensuring good electrical conductivity. These simulations verify that the BP/SnSe vdW heterostructure has immense potential for application in the design of metal-ion battery technologies.

5.
Nanomaterials (Basel) ; 13(19)2023 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-37836344

RESUMEN

Perovskite nanocrystals (PeNCs) have emerged as a promising class of luminescent materials offering size and composition-tunable luminescence with high efficiency and color purity in the visible range. PeNCs doped with Yb3+ ions, known for their near-infrared (NIR) emission properties, have gained significant attention due to their potential applications. However, these materials still face challenges with weak NIR electroluminescence (EL) emission and low external quantum efficiency (EQE), primarily due to undesired resonance energy transfer (RET) occurring between the host and Yb3+ ions, which adversely affects their emission efficiency and device performance. Herein, we report the synergistic enhancement of NIR emission in a CsPbCl3 host through co-doping with Yb3+/Nd3+ ions for perovskite LEDs (PeLEDs). The co-doping of Yb3+/Nd3+ ions in a CsPbCl3 host resulted in enhanced NIR emission above 1000 nm, which is highly desirable for NIR optoelectronic applications. This cooperative energy transfer between Yb3+ and Nd3+ can enhance the overall efficiency of energy conversion. Furthermore, the PeLEDs incorporating the co-doped CsPbCl3/Yb3+/Nd3+ PeNCs as an emitting layer exhibited significantly enhanced NIR EL compared to the single doped PeLEDs. The optimized co-doped PeLEDs showed improved device performance, including increased EQE of 6.2% at 1035 nm wavelength and low turn-on voltage. Our findings highlight the potential of co-doping with Yb3+ and Nd3+ ions as a strategy for achieving synergistic enhancement of NIR emission in CsPbCl3 perovskite materials, which could pave the way for the development of highly efficient perovskite LEDs for NIR optoelectronic applications.

6.
J Colloid Interface Sci ; 650(Pt B): 1725-1735, 2023 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-37506414

RESUMEN

Developing improved anode materials is critical to the performance enhancement and the lifespan prolonging of sodium-ion batteries (SIBs). In this context, carbon-based nanostructures have emerged as a promising candidate. In this work, we have synthesized N, B, and P tri-doped carbon (NBPC) spheres using a one-step carbonization method. The as-prepared NBPC exhibits exceptional properties, including an expanded layer space, sufficient structural defects, and enhanced electrical conductivity. These characteristics synergistically contribute to the remarkable rate capability and ultra-long lifespan when NBPC is employed as an anode material for SIBs. The as-prepared NBPC demonstrates a reversible capacity of 290.6 mAh/g at 0.05 A/g, with a capacity retention of 98.4% after 800 cycles. Furthermore, NBPC exhibits an impressively ultra-long cycle life of 2400 cycles at 1.0 A/g with a reversible capacity of 140.2 mAh/g. First principle calculations confirm that the introduction of N, B, and P heteroatoms in carbon enhances the binding strength of sodium ions within NBPC. This work presents a novel approach for fabricating advanced anode materials, enabling the development of long-life SIBs for practical applications.

7.
Plant Physiol ; 191(4): 2301-2315, 2023 04 03.
Artículo en Inglés | MEDLINE | ID: mdl-36660817

RESUMEN

Drought stress (DS) challenges sustainable agriculture production by limiting crop growth and development. The objective of the study was to evaluate the effect of melatonin-priming on enzymatic and non-enzymatic antioxidant defense mechanisms and its relation with leaf ultrastructure and stomatal traits in maize (Zea mays L) seedlings under DS (PEG-6000). DS drastically decreased seed germination, plant growth, and leaf chlorophyll content due to excessive reactive oxygen species (ROS) production. Melatonin-priming significantly (P < 0.05) increased seed germination, root length, shoot length, fresh seedling weight, proline content, total soluble protein content, sugar content, chlorophyll content, and stomatal aperture size by 101%, 30%, 133%, 51%, 22%, 59%, 54%, 20%, and 424%, compared to no priming (NP) under DS, respectively. Similarly, priming improved leaf ultrastructure and reduced the amount of chlorophyll loss and oxidative damage in maize seedlings. Melatonin seed priming with 500 µM melatonin (M2) greatly increased superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glutathione, and ascorbate (AsA) activity, by 65%, 63%, 94%, 41%, and 55% compared to NP under DS and by 0.26%, 8%, 33%, 42%, and 15% under no-stress (NS), respectively. Melatonin-priming also reduced malondialdehyde content, electrolyte leakage, hydrogen peroxide (H2O2) content, and superoxide anion (O2-) content by 26%, 31%, 31%, and 33% compared to NP under DS and by 8%, 18%, 10%, and 11% under NS, respectively. In response to DS, melatonin-priming also stabilized the chloroplast structure, sustained cell expansion, protected cell walls, and greatly improved stomatal traits, including stomatal number, length, and width. Our results suggest that melatonin-priming improves drought tolerance in maize seedlings by alleviating the negative effect of ROS.


Asunto(s)
Antioxidantes , Melatonina , Antioxidantes/metabolismo , Plantones/metabolismo , Melatonina/farmacología , Melatonina/metabolismo , Zea mays/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Resistencia a la Sequía , Peróxido de Hidrógeno/metabolismo , Clorofila/metabolismo
8.
J Ayub Med Coll Abbottabad ; 35(3): 447-451, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38404090

RESUMEN

BACKGROUND: Platelet concentrates play a crucial role in transfusion medicine, aiding in the management of various medical conditions, including haemorrhage, thrombocytopenia, and platelet dysfunction. However, their storage conditions at 22° C present an optimal environment for bacterial growth, making them susceptible to contamination. Of particular concern is the transmission of microorganisms from the skin flora during the phlebotomy process, which can lead to the transfusion of contaminated platelet concentrates. Such contamination poses significant risks to patients, potentially resulting in morbidity and mortality. Determining the frequency and identifying causative organisms of bacterial contamination in platelet concentrates. METHODS: It was a descriptive cross-sectional study conducted at the Institute of Pathology and Diagnostic Medicine, Khyber Medical University, and the Regional Blood Center in Peshawar from May to October 2021, spanning a duration of six months. The study included 500 participants aged between 18 and 50 years (mean: 28.13±7.67 years. A simple convenient sampling technique was employed. Blood products underwent screening for Hepatitis B, Hepatitis C, HIV, Syphilis, and Malaria. Leaked units were excluded from the study. Platelets were prepared using a Cryofuge and subsequently subjected to culture media. RESULTS: The mean age of the participants included in the study was 28.13±7.67 years, with an age range of 18 to 50 years. Out of the total sample size of 500, there were 483 (96.6%) male participants and 17 (3.4%) female participants. Among the collected samples, bacterial growth was observed in only 11 (2.2%) platelet concentrates. The isolated organisms were Staphylococcus epidermidis, found in 7 (1.4%) platelet concentrates, and Staphylococcus aureus, found in 4 (0.8%) platelet concentrates. CONCLUSIONS: Bacterial contamination of platelet bags is higher compared to developed countries. Therefore, implementing quality control procedures is necessary to reduce the risk of bacterial contamination in platelet concentrates. Additionally, employing enhanced skin disinfection techniques at the phlebotomy site can significantly minimize bacterial contamination.


Asunto(s)
Transfusión de Plaquetas , Infecciones Estafilocócicas , Humanos , Masculino , Femenino , Adolescente , Adulto Joven , Adulto , Persona de Mediana Edad , Transfusión de Plaquetas/efectos adversos , Estudios Transversales , Plaquetas , Bacterias
9.
Mol Biol Rep ; 49(12): 11573-11586, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36104582

RESUMEN

BACKGROUND: Vitamin C is a life saving molecule. Vitamin C based breeding is need of the hour in order to provide humans an immunity boosting supplement in the form of fresh food. METHODS AND RESULTS: Multiple interactions of Anatolian Mediterranean environment were studied with cultivars ('Calinda', 'Rubygem', 'Sabrina', and 'Sahara') and fruit maturity stages. Genetic expression of six vitamin C related genes was estimated showing significantly higher expression in open field. Cultivar 'Calinda' performed better in organic acids but poor in firmness. Cultivar 'Sabrina' showed highest fruit firmness but lower commercially desired fruit quality characters. Cultivar 'Sahara' performed best for vitamin C and fruit redness, and was high in fruit size, weight, and organic acids. Chroma trends indicated simultaneous accumulation of vitamin C and anthocyanins in strawberry fruits. Transition stage of fruits was found most critical for metabolite regulation and sensitive to environmental changes. Fruits of cultivar 'Sahara' at 'Red' maturity stage expressed highest vitamin C levels (138.03 mg/100 g FW) whereas 'Turning' fruits of cultivar 'Sabrina' had lowest vitamin C content (27.80 mg/100 g FW). All studied vitamin C related genes indicate highest genetic expression for cultivar 'Sahara', except for genes FaVTC2 and FaMDHAR which exhibit highest genetic expression for cultivar 'Rubygem.' CONCLUSION: Two-way and three-way interactions between cultivars, environments, and maturity stages were significant for vitamin C and fruit quality regulation under Mediterranean climate. This indicates an absolute requisite of studying combined influences in actual field, rather than single factor, controlled, or lab experiments. Correlation analysis showed that vitamin C content in a fruit is a complex subject and mainly depends on fruit color, size, and firmness. Principal Component Analysis validated that cultivar 'Sahara' is a promising candidate for vitamin C based breeding in strawberry.


Asunto(s)
Fragaria , Humanos , Fragaria/genética , Ácido Ascórbico , Frutas/genética , Consenso , Antocianinas , Fitomejoramiento , Vitaminas
10.
Am J Blood Res ; 12(3): 88-96, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35873102

RESUMEN

BACKGROUND AND OBJECTIVES: To determine the seroprevalence of SARS-CoV-2 antibodies and the associated risk factors among healthy blood donors from Peshawar Pakistan, during the second and third waves of the COVID-19 pandemic. METHODS: The study was conducted on 4047 healthy (with no history or symptoms of COVID-19) blood donors attending regional blood center Peshawar between Nov 2020 and June 2021. Demographic data was collected and donors were screened for the presence of anti-SARS-CoV-2 antibodies using electrochemiluminescence immunoassay (ECLIA). RESULTS: The mean age of the participants was 27.27±7.13 and the majority (99%) were males. Overall, 59% (2391/4047) of the blood donors were reactive for SARS-CoV-2 antibodies. An increasing trend in seropositivity was observed from 45.5% to 64.8% corresponding to the second and third wave of the pandemic in Pakistan. Logistic regression analysis revealed significantly higher odds of seropositivity among male donors compared to females. Similarly, in multivariable analysis, the odds ratio for seropositivity among blood types AB, A, and B were, 1.6, 1.4, and 1.3 (CI 95%) times higher compared to blood group O (P-value ≤0.0001). CONCLUSIONS: Seropositivity of SARS-CoV-2 antibodies among blood donors gradually increased during the second and third wave of the pandemic in Pakistan indicating a widespread prevalence of Covid-19 in the general population. Susceptibility to SARS-CoV-2 varies with ABO blood types, with blood group O associated with low risk of infection.

11.
J Environ Manage ; 317: 115385, 2022 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-35640404

RESUMEN

This study comparatively investigated the influence of changes in pyrolysis temperature on the physicochemical, structural, and adsorptive properties of biochars derived from a green waste (Cynodon dactylon L.). For this purpose, the biophysically dried green wastes were pyrolyzed at 400 °C, 600 °C, and 800 °C under the same pyrolysis conditions. The results revealed that the physicochemical and structural properties were varied, depending upon the pyrolysis temperatures. With the increase of pyrolysis temperature, the surface functional groups were escaped, the structure became more porous (pore volume of 0.089 ± 0.001), the metal oxides were remained consistent, and the biochars turned into more alkaline nature (pH of 11.9 ± 0.2). Furthermore, as referring to the adsorptive performance for potentially toxic elements, with experimental adsorption capacity of up to 33.7 mg g-1 and removal rate up to 96% for a multi-metals containing solution, the biochars pyrolyzed at high temperature (800 °C) was significantly (p < 0.05) higher than those pyrolyzed at low temperature (400 °C). According to the physicochemical and structural properties, and the adsorptive performances of the biochars, the optimal pyrolysis temperature was herein recommended to be 800 °C.


Asunto(s)
Carbón Orgánico , Pirólisis , Adsorción , Carbón Orgánico/química , Temperatura
12.
Nanomaterials (Basel) ; 12(7)2022 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-35407153

RESUMEN

Background: Using a variety of chemical compounds and biomolecules, researchers have been working on new antidiabetic drugs for many years. Anti-diabetic research is increasingly using nanomaterials because of their unique qualities, such as their tiny size, biocompatibility, and ability to penetrate cell membranes for drug delivery. Using extract of T. couneifolia coated with silver nanoparticles as a model for diabetes mellitus research was one of the goals of this work. Methods: Uv-Vis spectroscopy was used to measure the TAgNPs surface plasmon resonance. FTIR spectroscopy confirmed the attached functional groups, XRD analysis confirmed the size and crystallinity, scanning electron microscopy revealed that the majority of the particles were spherical, and EDX performed the elemental analysis. For 21 days, alloxan-induced diabetic Wistar rats (N = 25, n = 5/group) were administered 10 mg/kg body weight of photosynthesized AgNPs as a standard animal model, while those in the untreated normal control group C, received distilled water as a control, diabetics who were treated with 0.5 mg/kg of body weight of glibenclamide, 10 mg/kg of methanolic T. couneifolia extract, and diabetics who were given 10 mg/kg of body weight of synthetic AgNPs derived from T. couneifolia in the DAgNPs group. At the conclusion of the treatment, lipid, liver and kidney profiles were re-examined to determine whether or not the treatment had been effective (day 21). Oral glucose doses of 2 g/kg of body weight were administered to each group, and blood glucose levels were measured at various intervals (day 21). Fasting glucose levels were measured using a glucometer. Each animal's urine was tested for leukocytes, nitrites, and bilirubin using lab-made prepared assay kits. One-way ANOVA and Dunnett's test were used for statistical analysis. Results: The surface plasmon resonance effect was examined with UV-vis, it showed a sharp peak at 412 nm. X-ray diffraction measurements indicated that the produced nanoparticles were between 15 to 31.44 nm in size. Alloxan-induced diabetic rats were fed AgNPs derived from phytosynthesized AgNPs, compared to diabetic control rats, diabetic rats treated with AgNPs showed a considerable improvement in their dyslipidemia status. Over the course of the days, it also lowered blood glucose levels. A reduction in blood glucose levels, a rise in body weight, and significant improvements in the lipid, liver, and renal profiles were also seen. Conclusions: The present findings revealed that plant mediated silver nanoparticles significantly improved the alloxan induced diabetic changes in various treated rats and might be used for the treatment of diabetes.

13.
Nanomaterials (Basel) ; 12(5)2022 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-35269321

RESUMEN

Background: Type-2 diabetes mellitus (T2DM) is a non-communicable, life-threatening syndrome that is present all over the world. The use of eco-friendly, cost-effective and green synthesised nanoparticles (NPs) as a medicinal therapy in the treatment of T2DM is an attractive option. Aim: The present study aimed to evaluate the anti-diabetic potential of the phyto-synthesised silver nanoparticles (AgNPs) obtained from Phagnalon niveum plant methanolic extract. Methods: The green synthesised AgNPs made from Phagnalon niveum plant methanolic extract were analysed by Ultraviolet-Visible (UV-Vis) spectroscopy, and the functional groups involved in the reduction of the silver ions (Ag+) were characterised by Fourier Transform Infrared (FTIR) spectroscopy. The size and crystallinity were assessed via X-ray Diffraction (XRD). The morphology of AgNPs was confirmed using Scanning Electron Microscopy (SEM). The amount of silver (Ag) was estimated via energy dispersive X-ray (EDX) analysis. An intraperitoneal injection of 200 mg alloxan per kg albino Wistar rats' body weight, at eight weeks old and weighing 140-150 g, was used to induce diabetes mellitus (N = 25; n = 5/group). Group C: untreated normal control rats that only received distilled water, group DAC: diabetic control rats that received alloxan 200 mg/Kg body weight, DG: diabetic rats treated with glibenclamide at 0.5 mg/kg body weight, DE: diabetic rats that received methanolic P. niveum extract at 10 mg/Kg body weight, and DAgNPs: diabetic rates that received AgNPs synthesised from P. niveum at 10 mg/kg body weight. The blood glucose levels were monitored on days 0, 7, and 14, while lipid, liver, and kidney profiles were checked after dissection at the end of treatment (day 21). On the final day of the period study (day 21), an oral glucose tolerance test was carried out by administering orally 2 g/kg body weight of glucose to the respective groups, and the blood glucose level was checked. A fasting glucose level was measured using a glucometer. Urine samples were collected from each animal and analysed using lab-made assay kits for glucose, bilirubin, pH, leukocytes, and nitrite, among other factors. For statistical analyses, a one-way ANOVA and Dunnett's test were applied. Results: The green-mediated synthesis of AgNPs using P. niveum methanolic extract produced spherical and mono-dispersed NPs with a size ranging from 12 to 28 nm (average: 21 nm). Importantly, a significant reduction of blood glucose levels and an increase in body weight, as well as a remarkable improvement in lipid, liver, and kidney profiles, were noticed. Conclusions: The biosynthesised AgNPs significantly improved the abnormalities in body weight, urine, and serum levels, indicating that it is a promising anti-diabetic agent.

14.
Phys Chem Chem Phys ; 23(32): 17392-17401, 2021 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-34350913

RESUMEN

Van der Waals (vdW) heterostructure-based electrodes have invoked tremendous research interest due to their intriguing properties and their capability to break the limitations of the restricted properties of single-material systems. Herein, based on first-principles approaches, we propose that the black phosphorene/blue phosphorene (BLK-P/BLE-P) vdW heterostructure can be a capable anode material for power-driving lithium-ion batteries (LIBs), as it exhibits a large theoretical capacity, together with a relatively strong binding strength compared with the individual BLK-P and BLE-P monolayers. Our calculation results show that the Li adatom prefers to intercalate into the interlayer of the BLK-P/BLE-P vdW heterostructure due to the synergistic interfacial effect, resulting in a high binding strength and a diffusivity comparable to the BLK-P and BLE-P monolayers. Subsequently, the theoretical specific capacity is found to be as high as 552.8 mA h g-1, which can be attributed to the much higher storage capacity of Li adatoms in the BLK-P/BLE-P vdW heterostructure. Furthermore, electronic structure calculations reveal that a large amount of charge transfer assists in semiconductor to metallic transition upon lithiation, which would ensure good electrical conductivity. These simulations prove that the BLK-P/BLE-P heterostructure has great potential in LIBs and is essential for future battery design.

15.
J Hazard Mater ; 419: 126450, 2021 10 05.
Artículo en Inglés | MEDLINE | ID: mdl-34323708

RESUMEN

In this study, industrial wastewater and groundwater were comparatively investigated for their physicochemical properties, concentrations of potentially toxic elements (PTEs), human health risks and pollution source(s). Every month, 34 wastewater samples and 26 groundwater samples were collected, for a duration of one year. The results showed that the physicochemical parameters and concentrations of PTEs in the industrial wastewater exceeded the maximum permissible limits of Pakistan Environmental Protection Agency (2000). Specifically, it was found that total dissolved solids (5%), total suspended solids (190%), chemical oxygen demand (107%), five-days biochemical oxygen demand (5.7 times), grease/oil (27.1 times), Fe (67%), Zn (29%), Mn (32%), Cu (27%), Ni (16%), Cr (8%), Pb (106%), and Cd (80%) were higher than the permissible limits. The carcinogenic and non-carcinogenic dermal health risks for wastewater irrigation group were significantly higher than the groundwater irrigation group. The hazard index of irrigation with industrial wastewater was 180 times higher than the groundwater. The principal component analysis indicated that industry was the main polluting source. The cluster analysis results of all PTEs (except Fe) were found in the same clade in the dendrogram, which showed a strong similarity within the monthly data set of the whole year. The study recommends using adjacent groundwater instead of industrial wastewater for irrigation purposes.


Asunto(s)
Metales Pesados , Aguas Residuales , Monitoreo del Ambiente , Humanos , Metales Pesados/análisis , Pakistán , Medición de Riesgo
16.
Rev Bras Parasitol Vet ; 30(2): e001221, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34076046

RESUMEN

In the present study, anthelmintic activities of Arundo (A.) donax L., Areca (Ar.) catechu L., and Ferula (F.) assa-foetida L. were determined. Leaves of A. donax L., latex of F. assa-foetida L. and seeds of Ar. catechu L. in different solvent fractions were subjected to in vitro (egg hatch assay; EHA, and adult motility assay; AMA) and in vivo (faecal egg count reduction test; FECRT) tests of anthelmintic activity using Haemonchus contortus model. In the AMA, crude aqueous methanol extracts (CAME) and ethyl acetate fractions of F. assa-foetida at 10 hr post-treatment showed maximum mortality of H. contortus at 12.5-50 mg mL-1. In the EHA, CAME of F. assa-foetida was identified as a potent ovicide based on its low LC50 (16.9 µg mL-1), followed in order by Ar. catechu and A. donax. Results from the FECRT also showed the extract of F. assa-foetida L. to be more effective than those of Ar. catechu L. and A. donax L., against the gastrointestinal parasitic nematodes. Chloroform and ethyl acetate fractions showed better anthelmintic activities against the adult worms in vitro, while CAME of these plants were better than their crude powders in vivo. It is recommended to document and investigate indigenous knowledge of possible medicinal plants to plan scientific trials that may justify their endorsement.


Asunto(s)
Antihelmínticos , Ferula , Haemonchus , Animales , Antihelmínticos/farmacología , Areca , Extractos Vegetales/farmacología , Poaceae
17.
Chemosphere ; 277: 130350, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33794433

RESUMEN

The impact of different biochars (BCs) on the physicochemical properties and immobilization of potentially toxic elements (PTEs) in contaminated soil irrigated with industrial wastewater for the last three decades was studied. Furthermore, the efficacy of applied BCs in reducing geostatistical risks was also evaluated. For this purpose, BCs were prepared from green waste (Cynodon dactylon L.) for the first time at different pyrolysis temperature (400 °C, 600 °C and 800 °C), and amended the contaminated soil in pots with two different ratios of 2% and 5% (w/w) under controlled conditions. The BCs amended soil samples were analyzed after five months (equivalent to the life span of a wheat crop). The physicochemical impacts of applied BCs on the soil showed that the acidic soil was changed to basic. A tremendous increase in water holding capacity, cation exchange capacity, dissolved organic carbon, carbon, phosphorus and potassium contents was observed. The PTEs concentrations and geostatistical risks were significantly (p ≤ 0.05) decreased by all the BCs. Among them, BC prepared at 800 °C and applied at a ratio of 5% was showed the best effects by reducing the bioavailable concentrations of Cd, Pb, Cr, Ni, Cu, Mn, Fe, As, Co and Zn in 88%, 87%, 78%, 76%, 69%, 65%, 64%, 63%, 46% and 21%, respectively. Similarly, significant (p ≤ 0.05) reductions in geoaccumulation index, enrichment factor, contamination factor, and ecological risk were recorded. Therefore, BC prepared at 800 °C and applied at a ratio of 5% is recommended for soil remediation.


Asunto(s)
Metales Pesados , Contaminantes del Suelo , Carbón Orgánico , Metales Pesados/análisis , Suelo , Contaminantes del Suelo/análisis
18.
Arch Environ Contam Toxicol ; 80(1): 41-54, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33386942

RESUMEN

The focus of the present study was to assess the quality of different drinking water sources, impacts of poor water quality on human health, and to apportion pollution source(s) of the district Bajaur, Pakistan. Drinking water samples (n = 331) were randomly collected from springs, hand pumps, open wells, and tube wells and analyzed for physicochemical parameters including toxic elements, and bacteriological contamination (i.e., Escherichia coli). Furthermore, a questionnaire survey was conducted to record the cases of waterborne diseases in the study area. The results showed that total suspended solids and bacteriological contamination exceeded the permissible limits of the WHO in all four of the water sources. Among the potentially toxic elements, Cd, Pb, and Mn were above the permissible limits of the WHO in some samples. The hazard index for spring water was found to exceed the toxicity level (i.e., HI > 1) set by US EPA for both adults and children, while the sources from hand pumps, open wells, and tube wells were within the safe limit. The order for the overall safety level for water quality in the study area was tube wells > open wells > hand pumps > springs. The pollution source apportionment statistics revealed that both geogenic and anthropogenic activities are the sources of drinking water contamination. The results of the questionnaire survey indicated that reports of waterborne diseases were highest in respondents who took their drinking water from springs, whereas reports of diseases were moderate in respondents taking their water from open wells and hand pumps and lowest in respondents taking their water from tube wells. Based on the findings of the study, the tube well source of water is recommended for drinking water purposes.


Asunto(s)
Agua Potable/normas , Microbiología del Agua/normas , Contaminantes Químicos del Agua/análisis , Contaminación del Agua/análisis , Calidad del Agua/normas , Abastecimiento de Agua/normas , Adulto , Niño , Agua Potable/química , Agua Potable/microbiología , Humanos , Pakistán , Distribución Aleatoria , Medición de Riesgo , Abastecimiento de Agua/métodos , Abastecimiento de Agua/estadística & datos numéricos
19.
Rev. bras. parasitol. vet ; 30(2): e001221, 2021. tab, graf
Artículo en Inglés | LILACS | ID: biblio-1251379

RESUMEN

Abstract In the present study, anthelmintic activities of Arundo (A.) donax L., Areca (Ar.) catechu L., and Ferula (F.) assa-foetida L. were determined. Leaves of A. donax L., latex of F. assa-foetida L. and seeds of Ar. catechu L. in different solvent fractions were subjected to in vitro (egg hatch assay; EHA, and adult motility assay; AMA) and in vivo (faecal egg count reduction test; FECRT) tests of anthelmintic activity using Haemonchus contortus model. In the AMA, crude aqueous methanol extracts (CAME) and ethyl acetate fractions of F. assa-foetida at 10 hr post-treatment showed maximum mortality of H. contortus at 12.5-50 mg mL-1. In the EHA, CAME of F. assa-foetida was identified as a potent ovicide based on its low LC50 (16.9 µg mL-1), followed in order by Ar. catechu and A. donax. Results from the FECRT also showed the extract of F. assa-foetida L. to be more effective than those of Ar. catechu L. and A. donax L., against the gastrointestinal parasitic nematodes. Chloroform and ethyl acetate fractions showed better anthelmintic activities against the adult worms in vitro, while CAME of these plants were better than their crude powders in vivo. It is recommended to document and investigate indigenous knowledge of possible medicinal plants to plan scientific trials that may justify their endorsement.


Resumo No presente estudo, as atividades anti-helmínticas de Arundo (A.) donax L., Areca (Ar.) Catechu L. e Ferula (F.) assa-foetida L. foram determinadas. Folhas de A. donax L., látex de F. assa-foetida L. e sementes de Ar. catechu L. em diferentes frações de solvente foram submetidos a testes in vitro (teste de eclosão de ovos, EHA e ensaio de motilidade em adultos, AMA); e in vivo (teste de redução da contagem de ovos fecais, FECRT) de atividade anti-helmíntica, usando-se Haemonchus contortus. Na AMA, extratos aquosos brutos de metanol (CAME) e frações de acetato de etila de F. assa-foetida. Dez horas pós-tratamento, apresentaram mortalidade máxima de H. contortus em 12,5-50 mg mL-1. No EHA, CAME de F. assa-foetida foi identificado como um ovicida potente baseado em seu baixo LC50 (16,9 µg mL-1), seguido em ordem por Ar. catechu e A. donax. Os resultados do FECRT também mostraram que o extrato de F. assa-foetida L. é mais eficaz do que o de Ar. catechu L. e A. donax L., contra nematoides parasitas gastrointestinais. As frações clorofórmio e acetato de etila mostraram melhores atividades anti-helmínticas contra vermes adultos in vitro, enquanto o CAME dessas plantas foi melhor do que o pó bruto in vivo. Recomenda-se documentar e investigar o conhecimento indígena de possíveis plantas medicinais para planejar ensaios científicos que possam justificar seu endosso.


Asunto(s)
Animales , Ferula , Haemonchus , Antihelmínticos/farmacología , Areca , Extractos Vegetales/farmacología , Poaceae
20.
Environ Pollut ; 260: 113887, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-31982801

RESUMEN

In the present study, biochars (BCs) derived from naturally grown green waste (Cynodon dactylon L.) were investigated regarding their impacts on bioaccumulation of potentially toxic elements (PTEs), agronomic properties and human health risks of wheat crop cultivated on long-term industrially contaminated soil. Typically, three types of BCs were pyrolyzed at different highest temperature of treatment (HTT), i.e. 400 °C, 600 °C and 800 °C, in a horizontal reactor and applied to the contaminated soil with 2% and 5% (w/w) ratio. The characterization results of the BCs showed that significant positive changes in fundamental characteristics such as porosity, surface area, cation exchange capacity, dissolved organic carbon, phosphorus and potassium have occurred with increased HTT. The analytical results of wheat crop indicated that the BCs applications significantly (p ≤ 0.05) reduced concentration of PTEs in roots (48-95%), shoots (38-91%), leaves (30-91%) and grains (38-93%) of wheat plants. After the BCs application, the agronomic properties were enhanced up to 6-18%, 18-38%, 17-46%, 13-45%, 15-42%, 22-55% and 34-57% for germination rate, shoot length, shoot biomass, spike length, spike biomass, grain biomass and root biomass respectively. The human health risks of PTEs were significantly (p ≤ 0.05) decreased (31-93%) from toxicity level to safe level (except for Mn and Cu), after the BCs application. Based on the current study, the BCs (especially 800BC5) were recommended for reducing bioaccumulation of PTEs in different parts of the wheat plant, increasing growth and yield of wheat crop and decreasing human health risks via consumption of wheat grains.


Asunto(s)
Carbón Orgánico , Contaminantes del Suelo , Triticum , Bioacumulación , Biomasa , Carbón Orgánico/farmacología , Indicadores de Salud , Humanos , Suelo/química , Contaminantes del Suelo/metabolismo , Contaminantes del Suelo/toxicidad , Triticum/química , Triticum/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...