High-temperature tribological performance of stir-cast and heat-treated EV31A magnesium alloy: Experiments and predictions.

The temperature effect on the wear behaviour of EV31A Mg alloy during dry sliding wear was investigated. Wear tests were carried out at 50, 100, 150, 200, and 250 °C using a standard load of 10 N and a sliding distance of 1000 m. Weight loss method was used to calculate the wear rate. Optical microscopy was used to examine the microstructure of the EV31A alloy. FE-SEM with EDS analysis was used to investigate the wear morphology, and XRD analysis was performed both before and after the wear test. A high wear coefficient (K) value (more than 10-4) indicates extreme wear for EV31A in all the scenarios. T4 EV31A had a maximum wear rate of 20.2 mg at 150 °C. The as-cast EV31A alloy exhibits an excellent wear rate at the price of mechanical properties under all test scenarios. Wear resistance is improved by Nd and Zr oxides, although Mg and Gd oxides have little effect. Zn has no effect on the wear behaviour of the EV31A. In as-cast, T4, and T6 heat-treated conditions, the EV31A alloy exhibits delamination (abrasive wear), oxide development (corrosive wear), and delamination mixed with plastic deformation (adhesive wear). A Three-layered ANN and adapted Fine Gaussian SVM predicted tribological characteristics. In ANN prediction, the maximum R2 was 0.99 for CoF and 0.89 for wear rate, respectively. Despite the fact that the study's normal load is constant, machine learning models allow to deduce that temperature and normal load are the main influential parameters in CoF and wear rate, respectively.

Effect of Europium Addition on the Microstructure and Dielectric Properties of CCTO Ceramic Prepared Using Conventional and Microwave Sintering.

In this work, Eu2O3-doped (CaCu3Ti4O12)x of low dielectric loss have been fabricated using both conventional (CS) and microwave sintering (MWS), where x = Eu2O3 = 0.1, 0.2, and 0.3, respectively. According to X-ray diffraction (XRD) and scanning electron microscope (SEM) reports, increasing the concentration of Eu3+ in the CCTO lattice causes the grain size of the MWS samples to increase and vice versa for CS. The X-ray photoelectron spectroscopy (XPS) delineated the binding energies and charge states of the Cu2+/Cu+ and Ti4+/Ti3+ transition ions. Energy dispersive spectroscopy (EDS) analysis revealed no Cu-rich phase along the grain boundaries that directly impacts the dielectric properties. The dielectric characteristics, which include dielectric constant (ε) and the loss (tan δ), were examined using broadband dielectric spectrometer (BDS) from 10 to 107 Hz at ambient temperature. The dielectric constant was >104 and >102 for CS and MWS samples at x > 0.1, respectively, with the low loss being constant even at high frequencies due to the effective suppression of tan δ by Eu3+. This ceramic of low dielectric loss has potential for commercial applications at comparatively high frequencies.

Modern Synthesis and Sintering Techniques of Calcium Copper Titanium Oxide (CaCu3Ti4O12) Ceramics and Its Current Trend in Prospective Applications: A Mini-Review.

Calcium Copper Titanium Oxide (CaCu3Ti4O12/CCTO) has grasped massive attention for its colossal dielectric constant in high operating frequencies and wide temperature range. However, the synthesis and processing of CCTO directly influence the material's properties, imparting the overall performance. Researchers have extensively probed into these downsides, but the need for a new and novel approach has been in high demand. Modern synthesis routes and advanced non-conventional sintering techniques have been employed to curb the drawbacks for better properties and performance. This review provides a short overview of the modern synthesis and sintering methods that utilize direct pulse current and electromagnetic waves to improve the material's electrical, optical, and dielectric properties in the best ways possible. In addition, the current application of CCTO as a photocatalyst under visible light and CuO's role in the efficient degradation of pollutants in replacement for other metal oxides has been reviewed. This research also provides a brief overview of using CCTO as a photoelectrode in zinc-air batteries (ZAB) to improve the Oxidation-reduction and evolution (ORR/OER) reactions.

Insights on Spark Plasma Sintering of Magnesium Composites: A Review.

This review paper gives an insight into the microstructural, mechanical, biological, and corrosion resistance of spark plasma sintered magnesium (Mg) composites. Mg has a mechanical property similar to natural human bones as well as biodegradable and biocompatible properties. Furthermore, Mg is considered a potential material for structural and biomedical applications. However, its high affinity toward oxygen leads to oxidation of the material. Various researchers optimize the material composition, processing techniques, and surface modifications to overcome this issue. In this review, effort has been made to explore the role of process techniques, especially applying a typical powder metallurgy process and the sintering technique called spark plasma sintering (SPS) in the processing of Mg composites. The effect of reinforcement material on Mg composites is illustrated well. The reinforcement's homogeneity, size, and shape affect the mechanical properties of Mg composites. The evidence shows that Mg composites exhibit better corrosion resistance, as the reinforcement act as a cathode in a Mg matrix. However, in most cases, a localized corrosion phenomenon is observed. The Mg composite's high corrosion rate has adversely affected cell viability and promotes cytotoxicity. The reinforcement of bioactive material to the Mg matrix is a potential method to enhance the corrosion resistance and biocompatibility of the materials. However, the impact of SPS process parameters on the final quality of the Mg composite needs to be explored.

Real-world study of multiple naloxone administrations for opioid overdose reversal among emergency medical service providers.

Background: The increasing rates of highly potent, illicit synthetic opioids (i.e., fentanyl) in the US is exacerbating the ongoing opioid epidemic. Multiple naloxone administrations (MNA) may be required to successfully reverse opioid overdoses. We conducted a real-world study to assess the rate of MNA for opioid overdose and identify factors associated with MNA. Methods: Data from the 2015-2020 National Emergency Medical Services Information System was examined to determine trends in events requiring MNA. Logistic regression analysis was performed to determine factors associated with MNA. Results: The percentage of individuals receiving MNA increased from 18.4% in 2015 to 28.4% in 2020. The odds of an event requiring MNA significantly increased by 11% annually. The adjusted odds ratio (aOR) for MNA were greatest among males, when advanced life support (ALS) was provided, and when the dispatch complaint indicated there was a drug poisoning event. Conclusions: The 54% increase in MNA since 2015 parallels the rise in overdose deaths attributable to synthetic opioids. This growth is visible in all regions of the country, including the West, where the prevalence of illicitly manufactured synthetic opioids is intensifying. Given this phenomenon, higher naloxone formulations may fulfill an unmet need in addressing the opioid overdose crisis.

The need for multiple naloxone administrations for opioid overdose reversals: A review of the literature.

Background A growing challenge in the opioid epidemic is the rise of highly potent synthetic opioids, (i.e., illicitly manufactured fentanyl [IMF]) entering the US non-prescription opioid market. Successful reversal may require multiple doses of naloxone, the standard of care for opioid overdose. We conducted a narrative literature review to summarize the rates of multiple naloxone administrations (MNA) for opioid overdose reversal. Methods: A MEDLINE search was conducted for published articles using MESH search terms: opioid overdose, naloxone and multiple naloxone administration. Of the 2,101 studies identified, articles meeting inclusion/exclusion criteria were reviewed, categorized by primary and secondary outcomes of interest and summarized by data source and study design. Results: A total of 24 articles meeting eligibility criteria were included. Among EMS-based studies, MNA rates ranged from 9% to 53%; in general, bystander-reported studies were notably higher, from 16% to 89%. Variation in study design, data sources, year and geography, may have contributed to these ranges. Three studies that included longitudinal results reported a significant percent increase between 26% and 43% in annual MNA rates or a significant increase in mean naloxone doses over time (p < .001). Conclusions: This summary found that multiple naloxone administrations during opioid overdose encounters vary widely, have occurred in up to 89% of all opioid overdoses, and have significantly increased over time. Higher naloxone formulations may fulfill an unmet need in opioid overdose reversals, given the rising rates of overdoses involving IMF. Further studies are needed to gain a better understanding of MNA during opioid overdose encounters, particularly across a wider geographic region in the US in order to inform continuing efforts to combat the opioid epidemic.

Reviewing Performance Measures of the Die-Sinking Electrical Discharge Machining Process: Challenges and Future Scopes.

The most well-known and widely used non-traditional manufacturing method is electrical discharge machining (EDM). It is well-known for its ability to cut rigid materials and high-temperature alloys that are difficult to machine with traditional methods. The significant challenges encountered in EDM are high tool wear rate, low material removal rate, and high surface roughness caused by the continuous electric spark generated between the tool and the workpiece. Researchers have reported using a variety of approaches to overcome this challenge, such as combining the die-sinking EDM process with cryogenic treatment, cryogenic cooling, powder-mixed processing, ultrasonic assistance, and other methods. This paper examines the results of these association techniques on various performance measures, such as material removal rate (MRR), tool wear rate (TWR), surface roughness, surface integrity, and recast layer formed during machining, and identifies potential gap areas and proposes a solution. The manuscript is useful for improving performance and introducing new resolutions to the field of EDM machining.

Quantitative profiling of Marek's Disease Virus in vaccinated layer chicken.

The present study was undertaken to quantify the Marek's Disease Virus (MDV) serotypes in vaccinated commercial layer flocks at 7, 14, 21, 28, 35 and 60-90 days post vaccination (dpv) and to correlate the pathogenic Gallid herpesvirus 2 (GaHV-2, MDV1) load with vaccine viral load of Gallid herpesvirus 3 (GaHV-3, MDV2) and Meleagridis herpesvirus 1 (MeHV-1, MDV3). A total of 25 commercial layer flocks were selected in and around Namakkal district of Tamil nadu, India and the feather pulp (FP) and blood samples were collected. Out of 25 flocks, 14 were revaccinated with bivalent vaccine, six were revaccinated with monovalent vaccine apart from the initial bivalent vaccination done at hatchery and five flocks were not revaccinated. SYBR green based real time PCR was used for absolute quantification of MDV serotypes. The pathogenic MDV1 load had shown an increasing trend until 21 dpv followed by a dip and again had shown a constant uptick between 60 and 90 dpv in the flocks that went on to develop MD outbreak. The flocks which had not encountered any Marek's Disease outbreak had shown increasing trend of MDV2 and 3 load until 21 dpv followed by a slight decrease but maintained a higher load when compared to MDV 1 which had marked a sharp decline between 60 and 90 dpv. Outbreak of MD was observed in seven (28%) out of 25 flocks between 18 and 27 weeks of age. It includes, two out of fourteen farms (14%) revaccinated with bivalent vaccine, two out of six farms (33%) revaccinated with MDV3 vaccine and three out of five farms (60%) without revaccination. The overall mean of vaccine viral load at various stages of dpv was constantly low where as pathogenic MDV 1 load was constantly high between 60 and 90 dpv in the flocks that went on to develop Marek's Disease during later part of life.

Powder Metallurgical Processing and Characterization of Molybdenum Addition to Tungsten Heavy Alloys by Spark Plasma Sintering.

The effect of adding molybdenum to the heavy tungsten alloy of W-Ni-Fe on its material characteristics was examined in the current study. The elemental powders of tungsten, iron, nickel, and molybdenum, with a composition analogous to W-3Fe-7Ni-xMo (x = 0, 22.5, 45, 67.5 wt.%), were fabricated using the spark plasma sintering (SPS) technique at a sintering temperature of 1400 °C and under pressure of 50 MPa. The sintered samples were subjected to microstructural characterization and tested for mechanical strength. The smallest grain size of 9.99 microns was observed for the 45W-45Mo alloy. This alloy also gave the highest tensile and yield strengths of 1140 MPa and 763 MPa, respectively. The hardness increased with the increased addition of molybdenum. The high level of hardness was observed for 67.5Mo with a 10.8% increase in the base alloy's hardness. The investigation resulted in the alloy of 45W-7Ni-3Fe-45Mo, observed to provide optimum mechanical properties among all the analyzed samples.

Effect of Wettability and Uniform Distribution of Reinforcement Particle on Mechanical Property (Tensile) in Aluminum Metal Matrix Composite-A Review.

There is a massive demand for low-weight high strength materials in automotive, space aerospace, and even structural industries in this present engineering world. These industries attract composites only because of their high strength, resistance to wear, and low weight. Among these composites, metal matrix composite finds wide applications due to its elevated properties, excellent resistance property, corrosion resistance, etc. The reinforcements exist in particles, fiber, and whiskers. Among the three, particles play an important role because of their availability and wettability with the metal matrix. Additionally, among the various metal matrices such as aluminum, magnesium, copper, titanium, etc., aluminum plays a vital role among metal matrices because of its cost, availability in abundance, and castability. Stir casting is the most inexpensive and straightforward composite fabrication technique among the prevailing techniques. Even though so many factors contribute to the elevated property of composites, metal matrix, and reinforcement phase, uniform distribution and wettability are essential factors among all the other factors. This review aims to develop a composite with elevated property in a cost-effective manner. Cost includes metal matrix, reinforcement, and processing technique. Various works have been tabulated to achieve the above objective, and analysis was carried out on tensile strength concerning microstructure. This review paper explores the challenges in composite fabrication and finds a solution to overcome them.

Effect of Microwave and Conventional Modes of Heating on Sintering Behavior, Microstructural Evolution and Mechanical Properties of Al-Cu-Mn Alloys.

In this research, we intended to examine the effect of heating mode on the densification, microstructure, mechanical properties, and corrosion resistance of sintered aluminum alloys. The compacts were sintered in conventional (radiation-heated) and microwave (2.45 GHz, multimode) sintering furnaces followed by aging. Detailed analysis of the final sintered aluminum alloys was done using optical and scanning electron microscopes. The observations revealed that the microwave sintered sample has a relatively finer microstructure compared to its conventionally sintered counterparts. The experimental results also show that microwave sintered alloy has the best mechanical properties over conventionally sintered compacts. Similarly, the microwave sintered samples showed better corrosion resistance than conventionally sintered ones.

Effect of Molybdenum (Mo) Addition on Phase Composition, Microstructure, and Mechanical Properties of Pre-Alloyed Ti6Al4V Using Spark Plasma Sintering Technique.

The effect of molybdenum additions on the phases, microstructures, and mechanical properties of pre-alloyed Ti6Al4V was studied through the spark plasma sintering technique. Ti6Al4V-xMo (where x = 0, 2, 4, 6 wt.% of Mo) alloys were developed, and the sintered compacts were characterized in terms of their phase composition, microstructure, and mechanical properties. The results show that the equiaxed primary alpha and Widmänstatten (alpha + beta) microstructure in pre-alloyed Ti6Al4V is transformed into a duplex and globular model with the increasing content of Mo from 0 to 6%. The changing pattern of the microstructure of the sample strongly influences the properties of the material. The solid solution hardening element such as Mo enhances mechanical properties such as yield strength, ultimate tensile strength, ductility, and hardness compared with the pre-alloyed Ti6Al4V alloy.

Experimental and Numerical Analyses on the Buckling Characteristics of Woven Flax/Epoxy Laminated Composite Plate under Axial Compression.

The evolution of a sustainable green composite in various loadbearing structural applications tends to reduce pollution, which in turn enhances environmental sustainability. This work is an attempt to promote a sustainable green composite in buckling loadbearing structural applications. In order to use the green composite in various structural applications, the knowledge on its structural stability is a must. As the structural instability leads to the buckling of the composite structure when it is under an axial compressive load, the work on its buckling characteristics is important. In this work, the buckling characteristics of a woven flax/bio epoxy (WFBE) laminated composite plate are investigated experimentally and numerically when subjected to an axial compressive load. In order to accomplish the optimization study on the buckling characteristics of the composite plate among various structural criterions such as number of layers, the width of the plate and the ply orientation, the optimization tool "response surface methodology" (RSM) is used in this work. The validation of the developed finite element model in Analysis System (ANSYS) version 16 is carried out by comparing the critical buckling loads obtained from the experimental test and numerical simulation for three out of twenty samples. A comparison is then made between the numerical results obtained through ANSYS16 and the results generated using the regression equation. It is concluded that the buckling strength of the composite escalates with the number of layers, the change in width and the ply orientation. It is also noted that the weaving model of the fabric powers the buckling behavior of the composite. This work explores the feasibility of the use of the developed green composite in various buckling loadbearing structural applications. Due to the compromised buckling characteristics of the green composite with the synthetic composite, it has the capability of replacing many synthetic composites, which in turn enhances the sustainability of the environment.

Effect of Nano Copper on the Densification of Spark Plasma Sintered W-Cu Composites.

In the present work, nano Cu (0, 5, 10, 15, 20, 25 wt.%) was added to W, and W-Cu composites were fabricated using the spark plasma sintering (S.P.S.) technique. The densification, microstructural evolution, tensile strength, micro-hardness, and electrical conductivity of the W-Cu composite samples were evaluated. It was observed that increasing the copper content resulted in increasing the relative sintered density, with the highest being 82.26% in the W75% + Cu25% composite. The XRD phase analysis indicated that there was no evidence of intermetallic phases. The highest ultimate (tensile) strength, micro-hardness, and electrical conductivity obtained was 415 MPa, 341.44 HV0.1, and 28.2% IACS, respectively, for a sample containing 25 wt.% nano-copper. Fractography of the tensile tested samples revealed a mixed-mode of fracture. As anticipated, increasing the nano-copper content in the samples resulted in increased electrical conductivity.

Effect of Heating Modes on Reactive Sintering of Ca3Co4O9 Ceramics.

The traditional solid-state reaction method was employed to synthesize bulk calcium cobaltite (Ca349/Ca3Co4O9) ceramics via ball milling the precursor mixture. The samples were compacted using conventional sintering (CS) and spark plasma sintering (SPS) at 850, 900, and 950 °C. The X-ray diffraction (XRD) pattern indicates the presence of the Ca349 phase for samples sintered at 850 and 900 °C. In addition, SPS fosters higher densification (81.18%) than conventional sintering (50.76%) at elevated sintering temperatures. The thermo-gravimetric analysis (TGA) and differential thermal analysis (DTA) performed on the precursor mixture reported a weight loss of ~25.23% at a temperature range of 600-820 °C. This current work aims to analyze the electrical properties (Seebeck coefficient (s), electrical resistivity (ρ), and power factor) of sintered samples as a function of temperature (35-500 °C). It demonstrates that the change in sintering temperature (conventional sintering) did not evince any significant change in the Seebeck coefficient (113-142 µV/K). However, it reported a low resistivity of 153-132 µΩ-m and a better power factor (82-146.4 µW/mK2) at 900 °C. On the contrary, the SPS sintered samples recorded a higher Seebeck coefficient of 121-181 µV/K at 900 °C. Correspondingly, the samples sintered at 950 °C delineated a low resistivity of 145-158 µΩ-m and a better power factor (97-152 µW/mK2).

Dynamic Characteristics of Woven Flax/Epoxy Laminated Composite Plate.

Due to the growing environmental awareness, the development of sustainable green composites is in high demand in composite industries, mainly in the automotive, aircraft, construction and marine applications. This work was an attempt to experimentally and numerically investigate the dynamic characteristics of Woven Flax/Bio epoxy laminated composite plates. In addition, the optimisation study on the dynamic behaviours of the Woven Flax/Bio epoxy composite plate is carried out using the response surface methodology (RSM) by consideration of the various parameters like ply orientation, boundary condition and aspect ratio. The elastic constants of the Woven Flax/Bio epoxy composite lamina needed for the numerical simulation are determined experimentally using two methods, i.e., the usual mechanical tests as well as through the impulse excitation of vibration-based approach and made a comparison between them. The numerical analysis on the free vibration characteristics of the composite was carried out using ANSYS, a finite element analysis (FEA) software. The confirmation of the FE model was accomplished by comparing the numerical results with its experimental counterpart. Finally, a comparison was made between the results obtained through the regression equation and finite element analysis.

Genomic and phenotypic analysis of COVID-19-associated pulmonary aspergillosis isolates of Aspergillus fumigatus

The ongoing global pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the coronavirus disease 2019 (COVID-19) first described from Wuhan, China. A subset of COVID-19 patients has been reported to have acquired secondary infections by microbial pathogens, such as fungal opportunistic pathogens from the genus Aspergillus. To gain insight into COVID-19 associated pulmonary aspergillosis (CAPA), we analyzed the genomes and characterized the phenotypic profiles of four CAPA isolates of Aspergillus fumigatus obtained from patients treated in the area of North Rhine-Westphalia, Germany. By examining the mutational spectrum of single nucleotide polymorphisms, insertion-deletion polymorphisms, and copy number variants among 206 genes known to modulate A. fumigatus virulence, we found that CAPA isolate genomes do not exhibit major differences from the genome of the Af293 reference strain. By examining virulence in an invertebrate moth model, growth in the presence of osmotic, cell wall, and oxidative stressors, and the minimum inhibitory concentration of antifungal drugs, we found that CAPA isolates were generally, but not always, similar to A. fumigatus reference strains Af293 and CEA17. Notably, CAPA isolate D had more putative loss of function mutations in genes known to increase virulence when deleted (e.g., in the FLEA gene, which encodes a lectin recognized by macrophages). Moreover, CAPA isolate D was significantly more virulent than the other three CAPA isolates and the A. fumigatus reference strains tested. These findings expand our understanding of the genomic and phenotypic characteristics of isolates that cause CAPA.

Novel report on mutation in exon 3 of myostatin (MSTN) gene in Nilagiri sheep: an endangered breed of South India.

The variability in breeding program leads to rapid loss of genetic potential for which National Bureau of Animal Genetic Resources is emphasized to conserve the indigenous breeds. The variation in myostatin (MSTN) gene and its association with growth traits will throw light on its potential use as marker in selection. Hence, the study was conducted to detect polymorphism in exon 3 of MSTN, one of the most important growth regulatory gene and its association with growth in Nilagiri sheep breed. Blood samples were collected from Nilagiri sheep (n = 103) of South India and growth data up to 1 year of age was recorded. Genomic DNA was isolated and amplified for part of MSTN gene; PCR products were genotyped by restriction digestion (MspI) and confirmed by sequencing. Restriction digestion has revealed a single nucleotide polymorphism at locus G5622C in exon 3 which was confirmed by sequencing. The wild-type DNA molecule (MM) cleaved by MspI produced 301-bp and 314-bp fragments and those with mutation (mm) would remain undigested. The genotypic frequencies were MM (0.689) and Mm (0.311) with complete absence of mm genotype; and allelic frequencies were M (0.8445) and m (0.1555). The locus was in Hardy-Weinberg equilibrium. The association analysis revealed that there was no significant difference in mean birth, weaning, 6-, 9-, and 12-month weight between MM and Mm genotypes at g.5622G>C locus of exon 3 of MSTN gene. This is the first report of mutation in exon 3 of MSTN gene. The non-significant effect and absence of mm genotype at this locus needs further studies based on large population size and haplotype analysis.

Environmental triggers in IBD: a review of progress and evidence.

A number of environmental factors have been associated with the development of IBD. Alteration of the gut microbiota, or dysbiosis, is closely linked to initiation or progression of IBD, but whether dysbiosis is a primary or secondary event is unclear. Nevertheless, early-life events such as birth, breastfeeding and exposure to antibiotics, as well as later childhood events, are considered potential risk factors for IBD. Air pollution, a consequence of the progressive contamination of the environment by countless compounds, is another factor associated with IBD, as particulate matter or other components can alter the host's mucosal defences and trigger immune responses. Hypoxia associated with high altitude is also a factor under investigation as a potential new trigger of IBD flares. A key issue is how to translate environmental factors into mechanisms of IBD, and systems biology is increasingly recognized as a strategic tool to unravel the molecular alterations leading to IBD. Environmental factors add a substantial level of complexity to the understanding of IBD pathogenesis but also promote the fundamental notion that complex diseases such as IBD require complex therapies that go well beyond the current single-agent treatment approach. This Review describes the current conceptualization, evidence, progress and direction surrounding the association of environmental factors with IBD.

Classification of PCR-SSCP bands in T2DM by probabilistic neural network: a reliable tool.

A Probabilistic Neural Network (PNN) is a statistical algorithm and consists of a grouping of multi-class data. The conventional method of detection of DNA mutations by the human eye may not detect the minute variations in PCR-SSCP bands, which may lead to false positive or false negative results. The detection by photographic images may contain a blare (noise) caused during the time of photography; therefore, image processing techniques were used to reduce image noise. PCR-SSCP gels of T2DM patients (n = 100) and controls (n = 100) were initially photographed with equal ratio of pixels and later subjected to a two-stage analysis: feature extraction and PNN. The evaluation of the results was done by quality training and the accuracy was up to 95%, and the human eye analysis showed 80% mutation detection rate. This study proves to be very reliable and gives accurate and fast detection for mutation analysis in diabetes. This method could be extended for analysis in other human diseases.