Design and implementation of a universal converter for microgrid applications using approximate dynamic programming and artificial neural networks

This paper introduces a novel design for a universal DC-DC and DC-AC converter tailored for DC/AC microgrid applications using Approximate Dynamic Programming and Artificial Neural Networks (ADP-ANN). The proposed converter is engineered to operate efficiently with both low-power battery and single-phase AC supply, utilizing identical side terminals and switches for both chopper and inverter configurations. This innovation reduces component redundancy and enhances operational versatility. The converter's design emphasizes minimal switch usage while ensuring efficient conversion to meet diverse load requirements from battery or AC sources. A conceptual example illustrates the design's principles, and comprehensive analyses compare the converter's performance across various operational modes. A test bench model, rated at 3000W, demonstrates the converter's efficacy in all five operational modes with AC/DC inputs. Experimental results confirm the system's robustness and adaptability, leveraging ADP-ANN for optimal performance. The paper concludes by outlining potential applications, including microgrids, electric vehicles, and renewable energy systems, highlighting the converter's key advantages such as reduced complexity, increased efficiency, and broad applicability.

Chandrayaan-3 APXS elemental abundance measurements at lunar high latitude

The elemental composition of the lunar surface provides insights into mechanisms of the formation and evolution of the Moon1,2. The chemical composition of lunar regolith have so far been precisely measured using the samples collected by the Apollo, Luna and Chang'e 5 missions, which are from equatorial to mid-latitude regions3,4; lunar meteorites, whose location of origin on the Moon is unknown5,6; and the in situ measurement from the Chang'e 3 and Chang'e 4 missions7-9, which are from the mid-latitude regions of the Moon. Here we report the first in situ measurements of the elemental abundances in the lunar southern high-latitude regions by the Alpha Particle X-ray Spectrometer (APXS) experiment10 aboard the Pragyan rover of India's Chandrayaan-3 mission. The 23 measurements in the vicinity of the Chandrayaan-3 landing site show that the local lunar terrain in this region is fairly uniform and primarily composed of ferroan anorthosite (FAN), a product of the lunar magma ocean (LMO) crystallization. However, observation of relatively higher magnesium abundance with respect to calcium in APXS measurements suggests the mixing of further mafic material. The compositional uniformity over a few tens of metres around the Chandrayaan-3 landing site provides an excellent ground truth for remote-sensing observations.

A high-efficiency poly-input boost DC-DC converter for energy storage and electric vehicle applications

This research paper introduces an avant-garde poly-input DC-DC converter (PIDC) meticulously engineered for cutting-edge energy storage and electric vehicle (EV) applications. The pioneering converter synergizes two primary power sources-solar energy and fuel cells-with an auxiliary backup source, an energy storage device battery (ESDB). The PIDC showcases a remarkable enhancement in conversion efficiency, achieving up to 96% compared to the conventional 85-90% efficiency of traditional converters. This substantial improvement is attained through an advanced control strategy, rigorously validated via MATLAB/Simulink simulations and real-time experimentation on a 100 W test bench model. Simulation results reveal that the PIDC sustains stable operation and superior efficiency across diverse load conditions, with a peak efficiency of 96% when the ESDB is disengaged and an efficiency spectrum of 91-95% during battery charging and discharging phases. Additionally, the integration of solar power curtails dependence on fuel cells by up to 40%, thereby augmenting overall system efficiency and sustainability. The PIDC's adaptability and enhanced performance render it highly suitable for a wide array of applications, including poly-input DC-DC conversion, energy storage management, and EV power systems. This innovative paradigm in power conversion and management is poised to significantly elevate the efficiency and reliability of energy storage and utilization in contemporary electric vehicles and renewable energy infrastructures.

Custom-designed 3D printed feed spacers and TFN membranes with MIL-101(Fe) for water recovery by forward osmosis

In this work, a dual-pronged approach- (i) novel thin-film nanocomposite polyether sulfone (PES) membrane with MIL-101 (Fe) and (ii) 3D printed spacers were explored to enhance water recovery by forward osmosis. The concentration of PES, pore former, draw solution, and MIL-101(Fe) was optimised for maximum pure water flux (PWF) and minimum specific reverse solute flux (SRSF). The best membrane exhibited a PWF of 7.52 Lm-2 h-1 and an SRSF of 0.33 ± 0.03 gL-1 using 1.5 M NaCl and DI water feed. The M22 membrane with the diamond-type spacer demonstrated a PWF of 2.53 Lm-2 h-1 and SRSF of 0.75 gL-1 for emulsified oily wastewater feed. The novel spacer design imparted significant turbulence to the feed flow and a lower foulant resistance of 1.3 m-1 as compared to the ladder type (1.5 m-1) or commercial spacer (1.7 m-1). This arrangement could recover 19% pure water within 12 h of operation (98% oil rejection) with a ∼ 94% flux recovery after hydraulic wash.

Statistical optimized production of Phytase from Hanseniaspora guilliermondii S1 and studies on purification, homology modelling and growth promotion effect

This investigation was performed to obtain a promising phytase enzyme producing yeast. In this regard, the PSM was used to isolate the phytase-producing Hanseniaspora guilliermondii S1 (MG663578) from sugarcane juice. The SSF optimum conditions for phytase generation were optimized using (OVAT) one-variable-at-a-time strategy using both Box-Behnken design and shake flask method (g/100 ml: 0.05 yeast extract, 0.15 Peptone, 0.05 malt extract 0.50 dextrose, pH 5.8 and 28ᵒC). The protein model developed was shown to be adequate for phytase production (91% accuracy), with the greatest phytase productivity in shake flask with substrate jack fruit seed powder being 395 ± 0.43 U/ml compared to 365U/ml for the BBD projected value. Crude Phytase was partially purified with a protein recovery of 43%, revealing a molecular weight of 120 kDa. It had an enzyme kinetic value of Km 3.3 mM and a Vmax of 19.1 mol/min. The 3D structure of PhyS1 amino acid sequences (PhyS1. B99990002) was simulated using Modeler 9.23, and the validated result revealed that 86.7% were in the favored region by Ramachandran plot. The SAVES server verified the 3D PDB file as satisfactory, and the model (in.pdb format) was uploaded in the PMDB database with the accession number ID: PM0082974. At the lab level, Hanseniaspora guilliermondii S1 (MG663578) producing phytase exhibited successful plant growth promotion activity in Ragi - CO 19 (Eleusine coracana L.) and Rice -Navarai - IR 64 (Oryza sativa L.). As a result, a phytase-based formulation for sustainable agriculture must be developed and tested on a large scale in diverse geographical areas of agricultural lands to determine its effect and potential on plant development.

Preconceptional paternal caloric restriction of high-fat diet-induced obesity in Wistar rats dysregulates the metabolism of their offspring via AMPK/SIRT1 pathway

BACKGROUND

Obesity is a metabolic syndrome where allelic and environmental variations together determine the susceptibility of an individual to the disease. Caloric restriction (CR) is a nutritional dietary strategy recognized to be beneficial as a weight loss regime in obese individuals. Preconceptional parental CR is proven to have detrimental effects on the health and development of their offspring. As yet studies on maternal CR effect on their offspring are well established but paternal CR studies are not progressing. In current study, the impact of different paternal CR regimes in diet-induced obese male Wistar rats (WNIN), on their offspring concerning metabolic syndrome are addressed.

METHODS

High-fat diet-induced obese male Wistar rats were subjected to caloric restriction of 50% (HFCR-I) and 40% (HFCR-II) and then they were mated with normal females. The male parent's reproductive function was assessed by sperm parameters and their DNMT's mRNA expression levels were also examined. The offspring's metabolic function was assessed by physiological, biochemical and molecular parameters.

RESULTS

The HFCR-I male parents have shown reduced body weights, compromised male fertility and reduced DNA methylation activity. Further, the HFCR-I offspring showed attenuation of the AMPK/SIRT1 pathway, which is associated with the progression of proinflammatory status and oxidative stress. In line, the HFCR-I offspring also developed altered glucose and lipid homeostasis by exhibiting impaired glucose tolerance & insulin sensitivity, dyslipidemia and steatosis. However, these effects were largely mitigated in HFCR-II offspring. Regarding the obesogenic effects, female offspring exhibited greater susceptibility than male offspring, suggesting that females are more prone to the influences of the paternal diet.

CONCLUSION

The findings highlight that HFCR-I resulted in paternal undernutrition, impacting the health of offspring, whereas HFCR-II largely restored the effects of a high-fat diet on their offspring. As a result, moderate caloric restriction has emerged as an effective weight loss strategy with minimal implications on future generations. This underscores the shared responsibility of fathers in contributing to sperm-specific epigenetic imprints that influence the health of adult offspring.

Identification and physico-chemical characterization of microplastics in marine aerosols over the northeast Arabian Sea

Microplastics (MPs) in the atmosphere can undergo long-range transport from emission regions to pristine terrestrial and oceanic ecosystems. Due to their inherent toxic and hazardous characteristics, MPs pose serious risks to both human well-being and the equilibrium of ecosystem. The present study outlines the comprehensive characterization, spanning physical and chemical attributes of MPs associated with atmospheric aerosols. Total suspended particulates (TSPs) were collected on a quartz fibre filter by operating a high-volume sampler for 24 h during distinct years (March, 2016 and November, 2020) at a coastal location in the northeast Arabian Sea. Subsequent to the sampling, a series of techniques were applied including density separation. The assessment and scrutiny of the MPs was carried out using stereo-zoom microscopy with supplementary validation using advanced fluorescence microscopy for enhanced precision in identification. Our comparative assessment suggests peroxide treatment followed by density separation could be a robust procedure for the definitive identification and characterization of MPs in the atmosphere. Average total abundance of MPs was found to be 1.30 ± 0.14 n/m3 in 2016 and 1.46 ± 0.12 n/m3 in 2020 with fibres, fragments and films having similar relative contributions (41 %, 31 %, 28 % in 2016 and 40 %, 35 %, 25 % in 2020). Fibres were found to be dominant morphotype followed by fragments and films over the coastal region of the Arabian Sea. In order to unravel the detailed chemical nature of these MPs, spectral analysis using μ-FTIR was carried out. The outcome of the analysis showed prevailing polymers as polyvinyl chloride and polymethyl methacrylate (50545 %) as dominant polymers followed by polyester (15 %), styrene butyl methacrylate (11 %), and polyacetal (9 %). MPs present in the vicinity of the Arabian Sea have potential to supply nutrients and toxicants, consequently can contribute to the modulation of the surface water biogeochemical processes.

A randomized controlled study to compare first stick success with Instaflash technology: The FIRSST study

BACKGROUND

Peripheral intravenous catheters (PIVCs) are frequently used in clinical settings for intravenous access. Multiple attempts of PIVC insertions leads to patient discomfort, delay in treatment, associated complications, and extensive expenditure cost. Reduced number of attempts causes patient/nursing personnel satisfaction and expenditure costs. The present study evaluated performance efficacy of BD Venflon™ I with Instaflash needle technology (investigational device) as compared to the BD Venflon™ without Instaflash needle technology (control device).

METHODOLOGY

The PIVC insertions were randomized in the ratio 1:1 using either investigational or control device and were monitored for first stick success rate, ease of insertion, and patient satisfaction. Data was analyzed using R 4.0.3 and Microsoft Excel. Chi square test was used to establish association between two categorical variables.

RESULTS

In total, 1402 patients were analyzed for first attempt insertion success which showed 98.72% success rate in investigational device as compared to 88.87% success rate in case of the control device (p = 0.0004). Marginal differences were observed in ease of insertion in investigational (98.71%) and control devices (99%) signifying high satisfaction levels of nursing personnels. Positive responses were observed in investigational (98.01%) and control devices (99%) underlining satisfactory performances of overall patient experiences.

CONCLUSION

The present study showed that BD Venflon™ I with Instaflash needle technology enhanced first attempt insertion success rate along with marginal differences in its efficacy in comparison with the BD Venflon™ without Instaflash needle technology thus enhancing patient and nursing personnel satisfaction in turn making it a better alternative to be used in hospitals.

Cold atmospheric plasma mediated cell membrane permeation and gene delivery-empirical interventions and pertinence

Delivery of genetic material to cells is an integral tool to analyze and reveal the genetic interventions in normal cellular processes and differentiation, disease development and for gene therapy. It has profound applications in pharmaceutical, agricultural, environmental and biotechnological sectors. The major methods relied for gene delivery or transfection requires either viral vectors or xenogenic carrier molecules, which renders probabilistic carcinogenic, immunogenic and toxic effects. A newly evolved physical method, Cold atmospheric plasma induced transfection neither needs vector nor carriers. The 4th state of matter 'Plasma' is a quasineutral ionized gas-containing ions, neutral atoms, electrons and reactive radical molecules; and possess electric and magnetic field, along with emanating photons and UV radiations. Plasma produced at atmospheric pressure conditions, and having room temperature is conferred as Low temperature plasma or Cold atmospheric plasma. Selective and controlled application of cold atmospheric plasma on tissues creates temporary, restorable pores on cell membranes that could be diligently manipulated for gene delivery. Research in this regard attained pace since 2016. Cold atmospheric plasma induces transfection by lipid peroxidation, electroporation, and clathrin dependent endocytosis in cell membranes, by virtue of its reactive radicals and electric field. Plasma formed reactive radicals, especially 'OH' penetrates to the cell membrane and cleaves the phosphate head group of membrane lipids, peroxidize and detaches fatty acid tails. This decreases membrane thickness, increases membrane fluidity and permeability. Simultaneously plasma formed ions, electrons and reactive radicals accumulate over cells, generating local electric field and neutralize the negative charge of cell membrane. This induces stress on cell membrane and disrupts its structural integrity, by infringing the dynamic equilibrium between surface tension, spatial repulsion and linear tension between the head groups of phospholipids, generating minute pores. Neutralization of membrane charge promote foreign, external plasmid and gene movement towards cells and its enhanced binding with ligands and receptors on cell membrane, instigating clathrin dependent endocytosis. In vitro and in vivo studies have successfully delivered plasmids, linear DNA, siRNA and miRNA to several established cell lines like, HeLa, PC12, CHL, HUVEC, Jurkat, MCF, SH-SY5Y, HT, B16F10, HaCaT, LP-1, etc., and live C57BL/6 and BALB/c mice, using cold atmospheric plasma. This review delineates the cell surface mechanism of plasma-induced transfection, critically summarizes the research progress in this context, plasma devices used, and the inimitable features of this method. Metabolic activity, cell function, and viability are not adversely affected by this process; moreover, the cell permeating plasma-formed reactive radicals are effectively defended by cellular antioxidant mechanisms like superoxide dismutase, glutathione reductase and cytokines, alleviating its toxicity. A deeper understanding on mechanism of plasma action on cells, its aftermath, and the research status in this field would provide a better insight on future avenues of research.

A Systematic Review and Network Meta-Analysis Assessing the Impact of Adding First Generation Non-Steroidal Anti-Androgens (NSAA) to LHRH Agonists (LHRHa) in Men Receiving Radiotherapy for Localized Prostate Cancer

PURPOSE/OBJECTIVE(S)

Randomized clinical trials consistently demonstrate that the addition of androgen deprivation therapy (ADT) to prostate radiation therapy improves overall survival (OS). However, there is substantial heterogeneity regarding the type of ADT: LHRHa alone, first generation NSAA alone (e.g., bicalutamide) or combination androgen blockade (CAB) with NSAA and LHRHa. There are no published randomized trials in localized disease that specifically compare the efficacy of NSAA to LHRHa, nor the utility of CAB over monotherapy ADT. We herein performed a systematic review and network meta-analysis to assess the impact of NSAA in relation to LHRHa in men receiving radiotherapy for localized prostate cancer.

MATERIALS/METHODS

We performed a systematic literature search in PubMed to identify clinical trials of patients with localized prostate cancer for which ADT duration was the primary randomization variable. Both definitive and salvage radiation trials were included. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated from data extracted from published survival curves. A network meta-analysis was performed to compare OS by ADT regimens. We defined NSAA toxicity as early discontinuation of any ADT agent due to side effects given the inconsistent reporting of specific related toxicity. A meta-regression was performed to assess association with NSAA toxicity, adjusted for study year, patient age, T stage, Gleason score and total ADT duration. NSAA duration was assessed as a continuous variable.

RESULTS

Of the 11 trials (8,169 patients) with OS data, the median duration of any ADT was 3 months (range 0-36 months) and the median duration of NSAA specifically was 3.5 months (range 0-24 months). There was no significant difference in OS between those treated with LHRHa (n = 369) vs. CAB (n = 4,792; HR 1.10, 95% CI 0.78-1.55). Among those receiving CAB, increased NSAA duration did not improve OS (versus 0 months; 1-6 months HR 1.41, 95% CI 0.94-2.13; 7-12 months HR 1.43, 95% CI 0.87-2.34) when controlling for total ADT duration. Of the 19 trials (15,067 patients) with toxicity data, patients on NSAA (n = 503) appeared more likely to discontinue treatment early compared to those receiving LHRHa (n = 902), though this was not statistically significant (odds ratio [OR] 4.20, 95% CI 0.16-109.19). A longer duration of NSAA did not adversely affect ADT compliance. Patients were more likely to discontinue ADT prematurely, regardless of type, if the planned duration was longer (OR 1.08, 95% CI 1.07-1.09).

CONCLUSION

We did not detect an overall survival benefit to adding NSAA to LHRHa, and NSAA appeared less well tolerated than LHRHa in men receiving radiation therapy for localized prostate cancer. These data suggest that providers should consider LHRHa without the addition of a NSAA as optimal when clinically appropriate.

Cellular temperature probing using optically trapped single upconversion luminescence

BACKGROUND

The thermally coupled energy states that contribute to the upconversion luminescence of rare earth element-doped nanoparticles have been the subject of intense research due to their potential nanoscale temperature probing. However, the inherent low quantum efficiency of these particles often limits their practical applications, and currently, surface passivation and incorporation of plasmonic particles are being explored to improve the inherent quantum efficiency of the particle. However, the role of these surface passivating layers and the attached plasmonic particles in the temperature sensitivity of upconverting nanoparticles while probing the intercellular temperature has not been investigated thus far, particularly at the single nanoparticle level.

RESULTS

The analysis of the study on the thermal sensitivity of oleate-free UCNP, UCNP@SiO₂, and UCNP@SiO₂@Au particles is carried out at a single particle level in a physiologically relevant temperature range (299 K-319 K) by optically trapping the particle. The thermal relative sensitivity of the as-prepared upconversion nanoparticle (UCNP) is found to be greater than that of UCNP@SiO₂ and UCNP@SiO₂@Au particles in an aqueous medium. An optically trapped single luminescence particle inside the cell is used to monitor the temperature inside the cell by measuring the luminescence from the thermally coupled states. The absolute sensitivity of optically trapped particles inside the biological cell increases with temperature, with a greater impact on the bare UCNP, which exhibits higher values for thermal sensitivity than UCNP@SiO₂ and UCNP@SiO₂@Au. The thermal sensitivity of the trapped particle inside the biological cell at 317 K indicates the thermal sensitivity of UCNP > UCNP@SiO₂@Au > UCNP@SiO₂ particles.

SIGNIFICANCE AND NOVELTY

Compared to bulk sample-based temperature probing, the present study demonstrates temperature measurement at the single particle level by optically trapping the particle and further explores the role of the passivating silica shell and the incorporation of plasmonic particles on thermal sensitivity. Furthermore, thermal sensitivity measurements inside a biological cell at the single particle level are investigated and illustrated that thermal sensitivity at a single particle is sensitive to the measuring environment.

Geochemical tracing of synoptic scale modern dust transport over the Northeast Arabian Sea during the southwest monsoon

During the Southwest monsoon (SWM), aeolian dust is mainly supplied via wet deposition over the north-eastern Arabian Sea (NEAS). To understand their impact on the biogeochemistry of the Arabian Sea, it is important to identify their sources and characteristics. In this context, wet deposit particulate (WDP) samples were collected at a coastal station (Goa; 15.4° N, 73.8° E) in the NEAS during the SWM for three years. These samples were used to characterize and identify mineral dust sources using mineralogical, elemental, and isotopic (Sr and Nd) signatures. The WDP samples were classified as Beginning of Monsoon (BM, June samples), Mid Monsoon (MM, July-August samples) and End of Monsoon (EM, September samples). Clay mineralogical composition indicate high palygorskite content during BM, which subsequently found to decrease in MM, and almost negligible in EM. However, smectite is highest during MM, with moderate presence of palygorskite during this period. The considerable variation in the relative percentages of clay minerals suggests significant temporal variability in dust sources which is further corroborated by the radiogenic isotopic composition. A strong seasonality in the isotopic composition is observed with ⁸⁷Sr/⁸⁶Sr ratio being relatively less radiogenic during MM than the BM and highly radiogenic at the EM. Whereas Ɛ_Nd values show an opposite trend to ⁸⁷Sr/⁸⁶Sr ratios throughout the monsoon, with more radiogenic Ɛ_Nd in the MM, and less radiogenic at the EM. End member mixing plot indicate dominant contribution of dust from the Arabian Peninsula (ARB) and Northeast African (NEA) sources during BM and MM, while a shift towards the Thar desert and Southwest Asian (SWA) sources at the EM. Trace elements associated with different sources were quantified and suggest high Fe concentration is associated with NEA dust sources, despite of ARB is the major supplier of aeolian dust to the Arabian Sea.

Optically trapped SiO2@Au particle-dye hybrid-based SERS detection of Hg2+ ions

The selective ultra-sensitive detection of a very low concentration of analyte in a liquid environment using surface-enhanced Raman spectroscopy (SERS) is a challenging task owing to the poor reproducibility of the Raman signals arising from the nonstationary nature of the substrate. However, plasmonic metal particle-incorporated microparticles can be effectively 3-D arrested in a liquid environment that can serve as a stable SERS substrate by employing an optical trapping force. Herein, we demonstrate a 3-D optically trapped Au-attached SiO₂ microparticle as an efficient SERS substrate that can detect 512 pM for Rhodamine6G and 6.8 pM for crystal violet. Further, the substrate allows the simultaneous detection of multiple analytes. By utilizing the Raman signal from Rhodamine 6G as the probe beam, the selective detection of Hg²⁺ ions as low as 100 pM is demonstrated.

Assessment of aeolian dust concentration, elemental composition, and their wet and dry deposition fluxes over the Northeast Arabian Sea

Atmospheric aerosol over the Arabian Sea is significantly impacted by the long-range transported mineral dust from the surrounding continents. This transported mineral dust is hypothesized and tested during several studies to see the impacts on the surface ocean biogeochemical processes and subsequently to the Carbon cycle. It is, thus important to quantify dust contributions and their fluxes to the Arabian Sea. Here we assess temporal variability of dust concentration, their elemental characteristics as well as quantify their dry and wet deposition fluxes over the North-eastern Arabian Sea. The dust concentrations were found to vary from 59 to 132 µg m^-3 which accounts for 50% to 90% of total mass during dusty days. However, its contribution during pre and post dust storms ranges between 6% and 60%. Relatively higher dust dry deposition flux of 28 ± 7 mg m^-2 day^-1 (range: 20-44) is estimated for dusty days compared to pre and post dusty days (range: 0.4-22 mg m^-2 day^-1). In contrast to dry deposition fluxes, significantly higher fluxes are estimated from wet deposition, averaging around 240 ± 220 mg m^-2 day^-1. These values are five times higher than those reported from cruise samples collected over the Arabian Sea. The contribution of dust to aerosol mass is further ascertained using elemental composition, wherein a significant correlation was observed between Fe and Al (r² = 0.77) for samples collected during the dusty period, highlighting their similar crustal sources. Our estimation of dust flux over this region has implications for the supply of nutrients associated with natural dust to the surface water of the Arabian Sea.Implications: The Arabian Sea, one of the productive oceanic regions among the global oceans, has been identified as a perennial source of atmospheric CO₂. This basin is heavily impacted by atmospheric dust deposition/inputs owing to its geographical location being surrounded by arid and semi-arid regions. It has been hypothesized that aeolian dust plays a significant role in modulating surface water biogeochemical processes including primary productivity, in the Arabian Sea. Furthermore, modelling studies have highlighted on the role of dust (containing Fe) in fueling and enhancing primary productivity in the Arabian Sea. However, quantification of dust deposition fluxes (wet and dry) on seasonal time scale is missing in the literature. This paper aims to partially fulfil this research gap by providing a long-term data of wet and dry deposition fluxes over the northeastern Arabian Sea. We have also discussed their seasonal variability and factors affecting this flux. Thus, this study will be valuable contribution to the aeolian research community and have significant implication toward the role of aeolian deposition to the surface water biogeochemical processes in the Arabian Sea.

Luminescence studies of a Li2 Ca1-x SiO4 :xSm3+ phosphor for the generation of white light under NUV-excited phosphor converting LEDs

In this paper, we present new aspects of Sm³⁺ -doped pure Li₂ CaSiO₄ as a suitable candidate for white light emitting diode (WLED) applications. The samples were mainly prepared using a conventional modified solid-state synthesis technique. The structural studies were done using X-ray diffraction and Rietveld refinement. Instruments such as a scanning electron microscope (SEM) were used to obtain information about the morphology of the as-prepared samples. Photoluminescence (PL) analysis of phosphor samples for variable concentrations of doping ions with variable excitations were presented. When doped with Sm³⁺ in host Li₂ CaSiO₄ it emitted intense blue, green and red emissions and a more intense red emission peak (605 nm) under 408 nm excitation (near-UV-blue). Our study shows that the as-prepared phosphor may be useful for optical devices and mainly for WLEDs. The corresponding transitions of doping ions and concentration quenching effect were studied in detail. The 1931 Commission Internationale de l'Eclairage (x, y) chromaticity coordinates showed the distribution of spectral regions calculated from PL emission spectra and this was found (0.63, 0.36) in the red region, so the phosphor may be useful for near-UV-blue excited WLED applications.

Economic analysis of a hybrid intelligent optimization-based renewable energy system using smart grids

Renewable energy has seen a substantial increase in deployment as an alternative to traditional power sources. However, two fundamental constraints exist that preclude widespread adoption: the availability of the generated power and the expense of the equipment. One of the most critical difficulties with this sort of hybrid system is to appropriately design the Hybrid Renewable Energy System (HRES) elements so that they fulfill all load requirements while requiring the least amount of investment and running expenditures. This research proposes a novel technique for evaluating the optimal smart grid linking Hybrid Renewable Energy (Solar photovoltaic and wind) with battery, to increase profitability, dependability, and feasibility. A multiobjective function is suggested and constructed to be optimized utilizing two optimization algorithms: Enhanced Particle Swarm Optimization (EPSO) and Harris Hawks Optimization (HHO) algorithm with Fuzzy-Extreme Learning Machine (ELM). The primary goal for the HRES is to operate optimally to reduce the cost of energy generat ion through hourly day-ahead. Here, the Fuzzy-ELM is utilized to predict the required load of the smart grid-connected system and hybrid EPSO-HHO, which are introduced to solve the problem of HRES economic analysis. Finally, the suggested EPSO-EHO method is implemented in the MATLAB software, and its performance comparison is made with other existing methods such as PSO, WOA, and HHO. The simulation result shows that the cost of the newly suggested EPSO-HHO technique-based Hybrid Renewable Energy System is less than PSO, WOA, and HHO by 4.89 %, 4.51 %, and 4.05 %, respectively.

Two-factor-based RSA key generation from fingerprint biometrics and password for secure communication

In an asymmetric-key cryptosystem, the secure storage of private keys is a challenging task. This paper proposes a novel approach for generating the same public and private key pair on a need basis. Hence, the need for secure storage of the private key is done away with. The proposed approach for generating the key pair is based on two factors: fingerprint biometrics and password. A stable binary string is generated from the distances among pairs of minutiae points in a fingerprint using a gray code-based method. Experiments show that gray code representation significantly reduces the number of inconsistencies between the generated bit strings from two instances of the same fingerprint as against the binary code representation. Hence, the Reed–Solomon error correction code successfully corrects errors due to variations in multiple instances of the same fingerprint to induce stability in the generated string. Hash of the stable string generated from the fingerprint and the string generated from hashed password are XORed to derive a stable seed value. The proposed approach uses this seed value to generate two large prime numbers. These prime numbers are used to generate the public and private key pair using the RSA key generation method. This seed value ensures the generation of the same key pair every time. The experimental results show that the proposed approach can ensure a stable generation of the key. It is not required to store either the fingerprint template or the password. Moreover, the generated private key is also not stored. It can be regenerated on a need basis.

Secondary attack rate of COVID-19 among contacts and risk factors, Tamil Nadu, March-May 2020: a retrospective cohort study

OBJECTIVE

To describe the characteristics of contacts of patients with COVID-19 case in terms of time, place and person, to calculate the secondary attack rate (SAR) and factors associated with COVID-19 infection among contacts.

DESIGN

A retrospective cohort study SETTING AND PARTICIPANTS: Contacts of cases identified by the health department from 14 March 2020to 30 May 2020, in 9 of 38 administrative districts of Tamil Nadu. Significant proportion of cases attended a religious congregation.

OUTCOME MEASURE

Attack rate among the contacts and factors associated with COVID-19 positivity.

RESULTS

We listed 15 702 contacts of 931 primary cases. Of the contacts, 89% (n: 14 002) were tested for COVID-19. The overall SAR was 4% (599/14 002), with higher among the household contacts (13%) than the community contacts (1%). SAR among the contacts of primary cases with congregation exposure were 5 times higher than the contacts of non-congregation primary cases (10% vs 2%). Being a household contact of a primary case with congregation exposure had a fourfold increased risk of getting COVID-19 (relative risk (RR): 16.4; 95% CI: 13 to 20) than contact of primary case without congregation exposure. Among the symptomatic primary cases, household contacts of congregation primaries had higher RR than household contacts of other cases ((RR: 25.3; 95% CI: 10.2 to 63) vs (RR: 14.6; 95% CI: 5.7 to 37.7)). Among asymptomatic primary case, RR was increased among household contacts (RR: 16.5; 95% CI: 13.2 to 20.7) of congregation primaries compared with others.

CONCLUSION

Our study showed an increase in disease transmission among household contacts than community contacts. Also, symptomatic primary cases and primary cases with exposure to the congregation had more secondary cases than others.

Antioxidant Activities and Hepatoprotective Potential of Ethanol Leaf Extract of Justicia quinqueangularis against Selected Hepatotoxins Induced Hepatotoxicity in Albino Wistar Rats

Background: The objective of this research was to see whether the ethanolic extract of Justicia quinqueangularis leaves had antioxidant and hepatoprotective properties against paracetamol (PCT), ethanol (ETN), and isoniazid and rifampicin (IR)-induced hepatotoxicity in Albino Wistar rats. Methods: The leaves of Justicia quinqueangularis were dried in the shade at room temperature, pulverised, and extracted by soxhlet using ethanol. Quantitative phytochemical experiments were carried out as a first step. The ethanol extract's hepatoprotective activity was evaluated in Albino Wistar rats. PCT (3 g/kg), ETN (5 g/kg), and IR (100 mg/kg) reduced the levels of serum glutamic oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT), alkaline phosphatase (ALP) and bilirubin, which are all biochemical indicators of liver injury. Both hepatotoxin-treated and untreated group of animals determined for their antioxidant levels. SGOT, SGPT, ALP, bilirubin, antioxidant function of DPPH (2,2-diphenyl-1-picrylhydrazyl), hydrogen peroxide (H2O2), lipid peroxidation methods, hydroxyl radicals, and nitric oxide scavenging activities were among the biochemical and histopathological tests performed. Results: The altered levels of biochemical markers were restored to near normal levels in a dose-dependent fashion after treatment with J. quinqueangularis ethanol leaf extract (100 mg / kg, 200 mg / kg, and 400 mg / kg body weight). Conclusion: The findings of the current research indicated that the ethanol leaf extract of J. quinqueangularis had potent antioxidant and hepatoprotective properties against standard drug.

Evaluation of Hepatoprotective and Antioxidant Activity of Ethanolic Extract of Artabotrys zeylanicus Stem against Various Hepatotoxins Induced Hepatotoxicity in Albino Wister Rats

The objective of the present study was to investigate the antioxidant and hepatoprotective activity of ethanolic stem extract of Artabotrys zeylanicus against paracetamol (PCT), Ethanol (ETN) and Isoniazid and Rifampicin (IR) induced hepatotoxicity in Albino wister rats. Methodology: The material was dried in shade, they were powdered and extracted with ethanol. Preliminary Phytochemical tests were done. The hepatoprotective activity of the ethanol extract was assessed in Albino wister rats. PCT (3 g/kg), ETN (5 gm/kg) and IR (100 mg/kg) has enhanced the levels of various biochemical markers of hepatic damage like Serum Glutamic Oxaloacetic Trasaminase (SGOT), Serum Glutamic pyruvic transaminase (SGPT), Alkaline phosphatise (ALP), bilirubin. Antioxidant levels were tested in all the Hepatotoxins treated and untreated groups. Results: The various biochemical and Histopathological investigations done were Serum Glutamic Oxaloacetic Trasaminase (SGOT), Serum Glutamic pyruvic transaminase (SGPT), Alkaline phosphatise (ALP), Bilirubin, antioxidant activity by 1,1-diphenyl 2-picryl hydrazyl (DPPH), Nitro Blue Tetrazolium (NBT), Hyderogen peroxide (H2O2), lipid perioxidation, hyderoxil radical and nitric oxide. Treatment of ethanolic extract of stem of A. zeylanicus (100mg/kg, 200mg/kg and 400mg/kg body weight) has brought back the altered levels of biochemical markers to the near normal levels in the dose dependent manner. Ethanolic extract of A. zeylanicus were observed to inhibit oxidant stress with the maximum value of 71% and 62% at the concentration of 100 µg/mL. The crude ethanolic extract of A. zeylanicus had a calculated IC50 value of 62.2 and 63.25 μg/mL, which is nearly similar to the calculated IC50 value of the known antioxidant, ascorbic acid, ie 65.3 μg/mL. While the rats treated with AZ extract (100, 200 and 400 mg/kg) which were shown as reduction/absence of inflammatory cells, vascular congestion, cellular degeneration, necrosis and vacuoles. In contrast, the lower doses (100 mg/kg) of ethanolic extract of AZ stem shown low protection than at higher dose 400 mg/kg. Conclusion: Our findings suggested that A. zeylanicus ethanol stem extract possessed a potent antioxidant and hepatoprotective activity.

Tool Wear and Temperatures Analysis While Machining Ti-6Al-4V in MQCL-MIST Environment

Sustainable machining of titanium alloys have deficiency of studies on the built-up edges over the cutting tools and temperature correlation in minimum quantity cooling lubrication (MQCL) environment. Researchers focused on experimentation in dry, wet, and MQL (minimum quantity lubrication) conditions to analyze surface finish, cutting forces, and metal removal rates. This work focuses on the study of cutting parameters effects on temperatures and tool wear analysis by consideration of individual response and their optimality basing on signal-to-noise ratios. Efficacy of process parameters on wear of tool and temperatures requires a comprehensive understanding. An elaborated tool wear analysis is carried based on the microscopic flank wear investigations. Machining of Ti-6Al-4V alloy is carried in the environment of MQCL in form of mist using semi-synthetic fluid. Correlation study of tool wear with regard to temperatures is analyzed and regression models generated on tool wear and cutting temperatures individually showed 83% of goodness-of-fit and correlation regression is 85%.

Evaluation of bactericidal and virucidal activity of novel disinfectant Aaride AGT-1 compared to other commercially available disinfectants against hospital-acquired infections (HAIs)

Hand hygiene is the topmost crucial procedure to prevent hospital-acquired infections. Choosing an effective hand disinfectant is necessary in enforcing good hand hygiene practice especially in hospital settings. The aim of the study was to investigate the efficacy of Aaride AGT-1 as a hand disinfectant for the inhibition of pathogenic microorganisms' transmission among both patients and personnel in the health care system compared to other commercially available disinfectants. In the present study, a new hand disinfectant Aaride AGT-1 was tested against several bacterial and viral pathogens to evaluate its antimicrobial activity profile. The results revealed that Aaride AGT-1 displayed the highest antibacterial activity against five pathogenic bacteria including MRSA when compared to other commercially available hand sanitizers. Aaride AGT-1 showed the lowest percentage needed to inhibit the growth of bacterial pathogens. In addition, results obtained from time killing assay revealed that Aaride AGT-1 demonstrated the best killing kinetics, by eradicating the bacterial cells rapidly within 0.5 min with 6 log reduction (>99.99% killing). Also, Aaride AGT1 was able to reduce 100% plaque formed by three viruses namely HSV-1, HSV-2 and EV-71. In conclusion, Aaride AGT-1 is capable of killing wide-spectrum of pathogens including bacteria and viruses compared to other common disinfectants used in hospital settings. Aaride AGT-1's ability to kill both bacteria and viruses contributes as valuable addition to the hand disinfection portfolio.