Density Functional Theory Calculations on Electronic and Optical Properties of MOS2/Metal Heterojunction, MOS2/Graphene/Metal Vertical Heterostructure Interfaces and Sulfur Vacancies on MOS2/Au

In this study, we conducted a comprehensive investigation on computational simulations and analyses of heterostructures formed by two-dimensional (2D) molybdenum disulfide (MoS2) and graphene (Gr) on various metal coated substrates, including gold (Au), copper (Cu), nickel (Ni), and platinum (Pt). The frequency-dependent dielectric function (ɛ(ω)), refractive index (n), and reflectivity (R) are determined using light polarization parallel and perpendicular to the c axis of the 2D layers. Our findings reveal that MoS2/Au, MoS2/Cu, and MoS2/Pt heterostructures exhibit a direct bandgap at the K-point of the Brillouin zone, whereas their corresponding MoS2/MoS2/Metal structures present an indirect bandgap. The reduced interlayer spacing in MoS2/MoS2/Ni enhances electronic coupling between MoS2 layers and the Ni substrate, significantly altering the band structure through energy level shifts and band alignment changes. A Dirac point at the Fermi level is revealed by the band structure study of MoS2/Gr/Au and MoS2/Gr/Cu, suggesting that these heterostructures have only minor alterations brought about by interactions. By comparison, the MoS2/Gr/Pt and MoS2/Gr/Ni systems show a modest band gap of 0.15 eV and 0.16 eV, respectively, along with a slight displacement of the Dirac point toward the conduction band. The observed shift and the corresponding band gaps indicate a more robust connection between the metallic substrates (Ni and Pt) and graphene, which could potentially modify the heterostructures\u27 electrical characteristics. Flat bands are observed on sulfur vacancies in MoS2/Au structures. The optical properties exhibit peaks in the infrared and visible regions, decreasing towards the ultraviolet region. Similar optical behavior is noted for the parallel components of the electric field in all three cases of sulfur vacancy on MoS2/Au. In the low energy range (0−5.5 eV), the dielectric function exhibits anisotropic behavior for both the real and imaginary parts for almost all the structures; in the upper range (\u3e 5.5 eV), it exhibits isotropic behavior. In all configurations, there is a small electron transfer per atom from graphene to Au and MoS2, reinforcing graphene\u27s p-type semiconductor characteristics in the heterostructures and heterointerfaces. Similarly, charge transfer from Metals to MoS2 confirms MoS2 as an n-type semiconductor. Among the configurations studied, MoS2/Gr/Pt exhibits the highest work function, correlating with the lowest electrical conductivity. Hence, this work intends to investigate the heterostructures\u27 distinctive physical property features with wide-ranging applications in optoelectronics, integrated nano photonics, electro catalytic and photo-electrochemical energy generation

Reconstruction of hydrologic and climatic variability in the Colorado River Basin

This dissertation investigated the reconstruction of hydrologic and climate variability in the Colorado River Basin for the past 500 years. Unimpaired streamflow stations and regional April 1 snow water equivalent of the basin were reconstructed using tree-ring chronologies as predictors in Partial Least Squares Regression (PLSR). Regional April 1 snow water equivalent time series was developed with principal component analysis and cluster analysis on snow course stations in the basin. For the reconstruction of unimpaired streamflow and regional April 1 snow water equivalent, all available standard tree-ring chronologies inside the Colorado River Basin were screened based on the correlation criterion (\u3e95% significance level). Then, PLSR was run using the cross validation approach (i.e. removing the least correlated screened tree-ring chronologies) to obtain an optimal result. Further, a PLSR reconstruction was compared with the different reconstruction procedures (Stepwise Linear Regression and Stepwise Principal Component Regression) in order to find the preferred method for climate variable reconstruction. Finally, the non-parametric rank sum test was performed to evaluate the individual and coupled impact of interannual and interdecadal ocean climate phenomenon on climate variables (streamflow and snowpack) of the basin using extended records; The major contributions of this research are divided into three major categories. First, unimpaired streamflow stations in the Colorado River basin were reconstructed using the Partial Least Square Regression (PLSR) technique. The current practice of reconstructing streamflows by using multiple linear regression and principal component regression were compared with the performance of Partial Least Square Regression technique (PLSR) based on cross validation standard error. The spatial and temporal variability of drought was evaluated for all the unimpaired streamflow stations and the different centuries in the record. Second, snowpack was regionalized using principal component and cluster analysis which helps to identify coherent regions in the basin. Further, regionalized snowpack was reconstructed for the past 500 years using the PLSR in order to understand the long-term regional spatial and temporal variability of drought in the basin. Third, the teleconnection study between interannual and interdecadal ocean climate phenomenon and climate variables (streamflow and snowpack) in the region was performed using reconstructed data considering different lag years (0, +1, +2 and +3); The outcome of this research identified an improved reconstruction approach to extend the climate variables (unimpaired streamflow and snowpack), regionalized climate variables, and determined the relationship between reconstructed climate variables and reconstructed large-scale ocean atmospheric patterns. These outcomes will help to improve the current practice of drought management planning and drought forecasting in the western United States

Learning Chemistry through Interactive Demonstration: A Pedagogical Perspective

This study was carried out to determine the achievement of school students in learning chemistry. Based on a quasi-experimental research strategy, this study looks at chemistry education at the secondary level. We chose three purposively selected public schools and six selected science teachers from those schools. A simple random sample was used to pick 120 students (57 females and 63 males). Generated data from CAT and CAS were examined manually and with IBM SPSS version -21. Pre-test results showed no significant differences in student performance by group or gender. Students in the experimental group performed well on the post-test, indicating that the interactive demonstration approach effectively taught chemistry. There was no need for students to act differently based on their gender, and they were all very supportive of each other's academic success. Most pupils struggle with understanding the concept of a chemical reaction. Overall, this study's findings imply that interactive demonstration substantially impacts student achievement and that gender does not play a role in student success. Thus, the interactive demonstration method (IDM) is advocated for use in the classroom to help students learn and understand the types of chemistry they will experience in their daily lives

Production and purification of xylooligosaccharides from oil palm empty fruit bunch fibre by a non-isothermal process

Oil palm empty fruit bunches (OPEFB) fibre, a by-product generated from non-woody, tropical perennial oil palm crop was evaluated for xylooligosaccharides (XOS) production. Samples of OPEFB fibre were subjected to non-isothermal autohydrolysis treatment using a temperature range from 150 to 220 ºC. The highest XOS concentration, 17.6 g/L which relayed from solubilisation of 63 g/100 g xylan was achieved at 210 ºC and there was a minimum amount of xylose and furfural being produced. The chromatographic purification which was undertaken to purify the oligosaccharide-rich liquor resulted in a product with 74–78% purity, of which 83–85% was XOS with degree of polymerisation (DP) between 5 and 40

RETRACTED: Innovative Practices for the Promotion of Local/Indigenous Knowledge for Disaster Risk Reduction Management in Sudur Paschim Province, Nepal

The description of the Retraction: This article has been retracted. The Original article has previously been published elsewhere without disclosure to the editor, permission to republish, or justification (ie, redundant publication).We apologise for any inconvenience this retraction may have caused readers.Refers to :RETRACTED: Innovative Practices for the Promotion of Local/Indigenous Knowledge for Disaster Risk Reduction Management in Sudur Paschim Province, NepalKabi Prasad Pokhrel, Shambhu Prasad Khatiwada, Narayan Prasad Paudyal, Keshav Raj Dhakal, Chhabi Lal Chidi, Narayan Prasad Timilsena, Dhana Krishna MahatJournal of Geographical Research, Volume 4, Issue 3, July 2021DOI of original article: https://doi.org/10.30564/jgr.v4i3.322

A suberized exodermis is required for tomato drought tolerance.

Plant roots integrate environmental signals with development using exquisite spatiotemporal control. This is apparent in the deposition of suberin, an apoplastic diffusion barrier, which regulates flow of water, solutes and gases, and is environmentally plastic. Suberin is considered a hallmark of endodermal differentiation but is absent in the tomato endodermis. Instead, suberin is present in the exodermis, a cell type that is absent in the model organism Arabidopsis thaliana. Here we demonstrate that the suberin regulatory network has the same parts driving suberin production in the tomato exodermis and the Arabidopsis endodermis. Despite this co-option of network components, the network has undergone rewiring to drive distinct spatial expression and with distinct contributions of specific genes. Functional genetic analyses of the tomato MYB92 transcription factor and ASFT enzyme demonstrate the importance of exodermal suberin for a plant water-deficit response and that the exodermal barrier serves an equivalent function to that of the endodermis and can act in its place

Extensive profiling of three varieties of Opuntia spp. fruit for innovative food ingredients

[EN] Consumer interest in the use of natural ingredients is creating a growing trend in the food industry, leading to research into the development of natural products such as colorants, antimicrobials and antioxidant compounds. This work involves an extensive morphological (using physico-chemical assays), chemical (antioxidant activity assays) and microbiological (Gram-positive and negative strains) characterization of prickly peras (Opuntia ficusindica (OFI) var. sanguigna, gialla and Opuntia engelmannii) fruits. Through chromatographic assays, these species have shown interesting contents of hydrophilic (sugars, organic acids and betalains) and lipophilic (tocopherols and fatty acids) compounds. While Opuntia engelmannii exhibited higher content of betacyanins and mucilage, OFI varieties sanguigna and gialla displayed greater organic acid content. The sanguigna variety also showed the highest ¿-tocopherol content. All this compounds could be the responsible of enhancing the bioactivity of this variety, which can be observed in its antimicrobial potential, tested in the studied strains too. Results revealed that Opuntia spp. could be used as a nutraceutical and/or food additive, maintaining and promoting health and life quality.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013) and L. Barros contract. This work is funded by the European Structural and Investment Funds (FEEI) through the Regional Operational Program North 2020, within the scope of Project NORTE-01-0145-FEDER-023289 (DeCodE) and ValorNatural (R). B. Melgar (No. 329930) also thanks CONACyT for his grant. The authors are grateful for a grant from the Serbian Ministry of Education, Sciences and Technological Development (no. 173032). The authors would also like to thank Dr. Carlos Aguiar for the botanical identification of these species.Melgar-Castañeda, B.; Pereira, E.; Oliveira, MBP.; Garcia-Castello, EM.; Rodríguez López, AD.; Sokovic, M.; Barros, L.... (2017). Extensive profiling of three varieties of Opuntia spp. fruit for innovative food ingredients. Food Research International. 101:259-265. https://doi.org/10.1016/j.foodres.2017.09.024S25926510