Bimetallic Single‑Atom Catalysts for Water Splitting

Green hydrogen from water splitting has emerged as a critical energy vector with the potential to spearhead the global transition to a fossil fuel-independent society.The field of catalysis has been revolutionized by single-atom catalysts(SACs),which exhibit unique and intricate interactions between atomically dispersed metal atoms and their supports.Recently,bimetallic SACs(bimSACs)have garnered significant attention for leveraging the synergistic functions of two metal ions coordinated on appropriately designed supports.BimSACs offer an avenue for rich metal–metal and metal–support cooperativity,potentially addressing current limitations of SACs in effectively furnishing transformations which involve synchronous proton–electron exchanges,substrate activation with reversible redox cycles,simultaneous multi-electron transfer,regulation of spin states,tuning of electronic properties,and cyclic transition states with low activation energies.This review aims to encapsulate the growing advancements in bimSACs,with an emphasis on their pivotal role in hydrogen generation via water splitting.We subsequently delve into advanced experimental methodologies for the elaborate characterization of SACs,elucidate their electronic properties,and discuss their local coordination environment.Overall,we present comprehensive discussion on the deployment of bimSACs in both hydrogen evolution reaction and oxygen evolution reaction,the two half-reactions of the water electrolysis process.

Plant Pollen Grains:A Move Towards Green Drug and Vaccine Delivery Systems

Pollen grains and plant spores have emerged as innovative biomaterials for various applications such as drug/vaccine delivery,catalyst support,and the removal of heavy metals.The natural microcapsules comprising spore shells and pollen grain are designed for protecting the genetic materials of plants from exterior impairments.Two layers make up the shell,the outer layer(exine)that comprised largely of sporopollenin,and the inner layer(intine)that built chiefly of cellulose.These microcapsule shells,namely hollow sporopollenin exine capsules have some salient features such as homogeneity in size,non-toxic nature,resilience to both alkalis and acids,and the potential to withstand at elevated temperatures;they have displayed promising potential for the microencapsulation and the controlled drug delivery/release.The important attribute of mucoadhesion to intestinal tissues can prolong the interaction of sporopollenin with the intestinal mucosa directing to an augmented effectiveness of nutraceutical or drug delivery.Here,current trends and prospects related to the application of plant pollen grains for the delivery of vaccines and drugs and vaccine are discussed.

Bongardia chrysogonum(L.)Spach:a valuable source for nutraceutical and pharmacological industries

Background:Bongardia chrysogonum(L.)Spach,also known as“Uruf-el-Deek”,has been used by rural communities for the treatment of various diseases and disorders,owing to its wide array of secondary metabolite compositions.Methods:The current study was conducted to determine the total polyphenolic content of Bongardia chrysogonum(L.)Spach as well as its potential free radical scavenging and metal-chelating antioxidant capacities.Its leaves,stems,and tubers were separately extracted using ethanol,water,and chloroform;their antioxidant activities were analyzed using in vitro models,including DPPH,ABTS,FRAP,and CUPRAC assays.The total polyphenolic content of the extracts was spectrophotometrically measured.Results:The richest polyphenolic content of the extracts was yielded by tuber chloroform and leaf ethanol extraction(215.09±0.53 mg/g extract as gallic acid equivalent and 240.74±1.12 mg/g extract as quercetin equivalent,respectively).Almost all of the tested extracts exhibited remarkable antioxidant activities,with the highest antioxidant capacity observed in the leaf extracts.On the other hand,the tuber ethanol extract demonstrated the weakest DPPH radical scavenging activity(%inhibition=49.75±0.38,P<0.01),while the tuber chloroform extract showed the weakest ABTS radical scavenging activity(%inhibition=62.61±0.06,P<0.05).These were closely followed by the tuber water extract(%inhibition=63.28±0.65,P<0.01).In terms of their FRAP and CUPRAC assays,the leaf ethanol extract was determined as the best one,with absorbance values of 3.64±0.01 and 2.22±0.01(P<0.01),respectively.Conclusion:Bongardia chrysogonum(L.)Spach possesses rich polyphenolic content and strong antioxidant activities.Thus,it could be a valuable source for the pharmaceutical industry in the prevention and treatment of diseases associated with oxidative stress.

Response of a 2-story test-bed structure for the seismic evaluation of nonstructural systems

A full-scale, two-story, two-by-one bay, steel braced-frame was subjected to a number of unidirectional ground motions using three shake tables at the UNR-NEES site. The test-bed frame was designed to study the seismic performance of nonstructural systems including steel-framed gypsum partition walls, suspended ceilings and fire sprinkler systems. The frame can be configured to perform as an elastic or inelastic system to generate large floor accelerations or large inter story drift, respectively. In this study, the dynamic performance of the linear and nonlinear test-beds was comprehensively studied. The seismic performance of nonstructural systems installed in the linear and nonlinear test-beds were assessed during extreme excitations. In addition, the dynamic interactions of the test-bed and installed nonstructural systems are investigated.

Prevascularized Micro‑/Nano‑Sized Spheroid/Bead Aggregates for Vascular Tissue Engineering

Efficient strategies to promote microvascularization in vascular tissue engineering,a central priority in regenerative medicine,are still scarce;nano-and micro-sized aggregates and spheres or beads harboring primitive microvascular beds are promising methods in vascular tissue engineering.Capillaries are the smallest type and in numerous blood vessels,which are distributed densely in cardiovascular system.To mimic this microvascular network,specific cell components and proangiogenic factors are required.Herein,advanced biofabrication methods in microvascular engineering,including extrusion-based and droplet-based bioprinting,Kenzan,and biogripper approaches,are deliberated with emphasis on the newest works in prevascular nano-and micro-sized aggregates and microspheres/microbeads.

Perspicacious Apprehension of HDTbNB Algorithm Opposed to Security Contravention

The exponential pace of the spread of the digital world has served as one of the assisting forces to generate an enormous amount of informationflow-ing over the network.The data will always remain under the threat of technolo-gical suffering where intruders and hackers consistently try to breach the security systems by gaining personal information insights.In this paper,the authors pro-posed the HDTbNB(Hybrid Decision Tree-based Naïve Bayes)algorithm tofind the essential features without data scaling to maximize the model’s performance by reducing the false alarm rate and training period to reduce zero frequency with enhanced accuracy of IDS(Intrusion Detection System)and to further analyze the performance execution of distinct machine learning algorithms as Naïve Bayes,Decision Tree,K-Nearest Neighbors and Logistic Regression over KDD 99 data-set.The performance of algorithm is evaluated by making a comparative analysis of computed parameters as accuracy,macro average,and weighted average.Thefindings were concluded as a percentage increase in accuracy,precision,sensitiv-ity,specificity,and a decrease in misclassification as 9.3%,6.4%,12.5%,5.2%and 81%.

Fast Single Image Haze Removal Method for Inhomogeneous Environment Using Variable Scattering Coefficient

The images capture in a bad environment usually loses its fidelity and contrast.As the light rays travel towards its destination they get scattered several times due to the tiny particles of fog and pollutants in the environment,therefore the energy gets lost due to multiple scattering till it arrives its destination,and this degrades the images.So the images taken in bad weather appear in bad quality.Therefore,single image haze removal is quite a bit tough task.Significant research has been done in the haze removal algorithm but in all the techniques,the coefficient of scattering is taken as a constant according to the homogeneous atmosphere but in real time this does not happen.Therefore,this paper introduces a simple and efficient method so that the scattering coefficient becomes variable according to the inhomogeneous environment.Then,this research aims to remove the haze with the help of a fast and effective algorithm i.e.,Prior Color Fading,according to the inhomogeneous environmental properties.Thereby,to filter the depth map,the authors used a weighted guided image filtering which removes the drawbacks of guided image filter.Afterwards the scattering coefficient is made variable according to the inhomogeneous atmosphere and then the Simple Color Balance Algorithm is applied so that the readability property of images can be increased.The proposed method tested on various general outdoor images and synthetic hazy images and analyzed on various parameters Mean Square Error(MSE),Root Mean Square Error(RMSE),Peak Signal to Noise Ratio(PSNR),Mean Structural Similarity(MSSIM)and the Universal Objective Quality Index(UQI).Experimental results for the proposed method show that the proposed approach provides better results as compared to the state-of-the-art haze removal algorithms.

Selective and effective oxidation of 5-hydroxymethylfurfural by tuning the intermediates adsorption on Co-Cu-CN_(x)

Co-based catalysts are promising alternatives to precious metals for the selective and effective oxidation of 5-hydroxymethylfurfural(HMF)to the higher value-added 2,5-furandicarboxylic acid(FDCA).However,these catalysts still suffer from unsatisfactory activity and poor selectivity.A series of N-doped carbon-supported Co-based dual-metal nanoparticles(NPs)have been designed,among which the Co-Cu_(1.4)-CN_(x) exhibits enhanced HMF oxidative activity,achieving FDCA formation rates 4 times higher than that of pristine Co-CN_(x),with 100%FDCA selectivity.Density functional theory(DFT)calculations evidenced that the increased electron density on Co sites induced by Cu can mediate the positive electronegativity offset to downshift the dband center of Co-Cu_(1.4)-CN_(x),thus reducing the energy barriers for the conversion of HMF to FDCA.Such findings will support the development of superior non-precious metal catalysts for HMF oxidation.

Facile biogenic selenium nanoparticle synthesis, characterization and effects on oxidative stress generated by UV in microalgae

Since nanoparticle synthesis via chemical and physical methods is expensive and includes hazardous chemicals,biosynthesis has emerged as an environmentally friendly,clean and viable alternative.The present study reports the synthesis of selenium nanoparticles(SeNPs)using Citricoccus sp..For the production of SeNPs,the influence of some parameters(time,pH,temperature and stirring rate)was studied.Optimum synthesis conditions were found as pH 8,24 h reaction time,37℃ and 150 rpm.Synthesized particles were spherical and were 104.46±50.82 nm with a zeta potential of–20.43±0.41 mV.Afterward,the effects of the nanoparticles on oxidative stress biomarkers,hydrogen peroxide(H_(2)O_(2)),malondialdehyde(MDA),chlorophyll(a+b)and growth rate,subsequent to UV-C irradiation on Chlorella vulgaris were investigated.In culture contains nanoparticle and UV-C exposed,the amount of H_(2)O_(2) and MDA decreased on the 1st,3rd and 7th days following UV exposure compared to UV-applied group,while optical density and cell density increased,the amount of chlorophyll(a+b)changes were statistically similar.Consequently,it has been shown that the synthesized SeNPs alleviated the adverse effects of UV stress in microalgae.

Exploring Sequence Space to Design Controllable G-Quadruplex Topology Switches

As nonclassical nucleic acid structures,G-quadruplexes(G4s)not only play important roles in gene regulation and stability maintenance,but are also widely used in nanotechnology.Structural diversity is one of the main factors explaining the popularity of G4s,but a comprehensive and integrated study of different factors determining G4 structural versatility is currently lacking.