Subnanometric Osmium Clusters Confined on Palladium Metallenes for Enhanced Hydrogen Evolution and Oxygen Reduction Catalysis

Highly efficient, cost-effective, and durable electrocatalysts, capable of accelerating sluggish reaction kinetics and attaining high performance, are essential for developing sustainable energy technologies but remain a great challenge. Here, we leverage a facile heterostructure design strategy to construct atomically thin Os@Pd metallenes, with atomic-scale Os nanoclusters of varying geometries confined on the surface layer of the Pd lattice, which exhibit excellent bifunctional properties for catalyzing both hydrogen evolution (HER) and oxygen reduction reactions (ORR). Importantly, Os5%@Pd metallenes manifest a low η10 overpotential of only 11 mV in 1.0 M KOH electrolyte (HER) as well as a highly positive E1/2 potential of 0.92 V in 0.1 M KOH (ORR), along with superior mass activities and electrochemical durability. Theoretical investigations reveal that the strong electron redistribution between Os and Pd elements renders a precise fine-tuning of respective d-band centers, thereby guiding adsorption of hydrogen and oxygen intermediates with an appropriate binding energy for the optimal HER and ORR.

A Detailed Study on using Novel LM 25 Aluminium Alloy Hybrid Metal Matrix Nanocomposite for Nuclear Applications

AIM

This article describes the use of graphite(Gr) and boron carbide (B4C) as multiple nanoparticle reinforcements in LM25 aluminum alloy. Because boron carbide naturally absorbs neutron radiation, aluminium alloy reinforced with boron carbide metal matrix composite has gained interest in nuclear shielding applications. The primary goal of the endeavor is to create composite materials with high wear resistance, high microhardness, and high ultimate tensile strength for use in nuclear applications.

BACKGROUND

Science and Technology have brought a vast change to human life. The human burden has been minimized by the use of innovation in developing new and innovative technologies. To improve the quality of human life, fresh, lightweight, and creative materials are being used, which play a vital role in science and technology and reduce the human workload. Composite materials made of metal are being used because they are lightweight. Neutron absorption, high ultimate strength, high wear resistance, high microhardness, high thermal and electrical conductivity, high vacuum environmental resistance, and low coefficient of thermal expansion under static and dynamic conditions are all demands for the hybrid metal matrix composites utilized in nuclear applications.

OBJECTIVE

• Stir casting is used to create the novel LM 25 aluminum alloy/graphite and boron carbide hybrid nanocomposites. • The mechanical properties such as ultimate tensile strength, yield strength, percentage of elongation, microhardness, and wear behavior are calculated. • Three analyses are performed: microstructure, worn surface analysis, and fracture analysis of the tensile specimen.

METHOD

• Stir casting process< • Tensile, Hardness, Wear Test • Materials Characterization - FESEM, Optical Microscopy, EDS< Results: The mechanical properties values are 308.76 MPa, 293.51 MPa, 7.8, 169.2 VHN, and 0.01854mm3/m intended for ultimate tensile strength, yield strength, percentage of elongation, microhardness, and wear behavior, respectively. This implies that the synthesized composite may be used in nuclear applications successfully.

CONCLUSION

The subsequent explanation was drawn from this investigative work: • The LM 25/B4C/Gr hybrid nanocomposite was successfully manufactured by employing the stir casting technique. For nuclear shielding applications, these composites were prepared with three different weight percentages of nanoparticle reinforcements in 2,4,6% Boron carbide and constant 4 wt.% graphite. • The microhardness values of the three-hybrid nanocomposite fabricated castings were determined to be 143.4VHN, 156.7VHN, and 169.2VHN, respectively. • The hybrid nano composite's microstructure revealed that the underlying LM 25 aluminum alloy matrix's finegrained, evenly dispersed nanoparticles of graphite and boron carbide were present.

• The microtensile test was carried out and it was found that the ultimate tensile strength, yield strength and percentage of elongation values are 281.35MPa, 296.52MPa, 308.76MPa, 269.43, 274.69, 293.51 and 3.4, 5.7, 7.8 respectively.

• Deformation caused the hybrid LM 25/B4C/Gr nanocomposite to fracture in ductile mode. Dimples and cavities are seen in the fracture because of the nanoparticle reinforcements and the matrix's tight connection.

• The wear loss of nanocomposite based on the input parameter applied load, sliding velocity and sliding distance values are 0.02456, 0.02189, 0.01854, 0.02892, 0.02586, 0.02315 and 0.02682, 0.02254, 0.02015 mm3/m, respectively.

• The LM 25 alloy's elemental analysis displays the aluminum alloy phase as the largest peak and the remaining elements as smaller peaks; also, the spectral analysis reveals the presence of boron (B), graphite (C), silicon, and ferrous in the aluminum alloy LM 25.

• Through worn surface FESEM investigation, it was shown that under sliding and high load situations, debris, delamination, and groove develop. Further rupture, fine, and continuous grooves were seen when low stress and sliding circumstances were applied to the LM 25/B4C/Gr and stir cast specimen. This result implies the presence of mild adhesive and delamination wear processes.

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Performance evaluation and chemical oxygen demand removal of tannery wastewater through the aerobic-anaerobic route

With characterized for complex and maximum substance (suspended solids, broke up oil, a mixture of inorganic and chromium sulfides), tannery wastewater was subjected to a treatment process on removal of chemical oxygen demand (COD) via upstream anaerobic sludge blanket reactor where we found reduced departure efficiencies and that process limits were affected by the assortments in regular stacking rates, closeness of chromium, and sulfides. Hence, a combination of the aerobic-anaerobic hybrid reactor was set up for sequential treatment to determine possible COD reduction. This study investigated the biological degradation of tannery wastewater in a laboratory-scale sequential up-flow aerobic-anaerobic reactor. The aerobic zone at the top was packed with spherical ball-shaped polyhedral polypropylene, and the anaerobic zone at the bottom was packed medium with granular media. The aeration flow rate varied by 2 L/min, 4 L/min, and 6 L/min in the aerobic zone, and the reactor maintained an organic loading rate (OLR) of 5 kg COD/m3/d. Parameters like COD and gas yield assess the performance of the reactor. The maximum COD of 86% is removed in the anaerobic zone with an aeration rate of 6 L/min, and the 1800-mL methane gas yield is measured by the 29th day.

Oxygen-Bridged Stabilization of Single Atomic W on Rh Metallenes for Robust and Efficient pH-Universal Hydrogen Evolution

Highly efficient and durable electrocatalysts are of the utmost importance for the sustainable generation of clean hydrogen by water electrolysis. Here, we present a report of an atomically thin rhodium metallene incorporated with oxygen-bridged single atomic tungsten (Rh-O-W) as a high-performance electrocatalyst for pH-universal hydrogen evolution reaction. The Rh-O-W metallene delivers ascendant electrocatalytic HER performance, characterized by exceptionally low overpotentials, ultrahigh mass activities, excellent turnover frequencies, and robust stability with negligible deactivation, in pH-universal electrolytes, outperforming that of benchmark Pt/C, Rh/C and numerous other reported precious-metal HER catalysts. Interestingly, the promoting feature of -O-W single atomic sites is understood via operando X-ray absorption spectroscopy characterization and theoretical calculations. On account of electron transfer and equilibration processes take place between the binary components of Rh-O-W metallenes, fine-tuning of the density of states and electron localization at Rh active sites is attained, hence promoting HER via a near-optimal hydrogen adsorption.

Pd-PdO Nanodomains on Amorphous Ru Metallene Oxide for High-Performance Multifunctional Electrocatalysis

Developing highly efficient multifunctional electrocatalysts is crucial for future sustainable energy  pursuits, but remains a great challenge. Herein, a facile synthetic strategy is used to confine atomically thin Pd-PdO nanodomains to amorphous Ru metallene oxide (RuO₂ ). The as-synthesized electrocatalyst (Pd₂ RuOx-0.5 h) exhibits excellent catalytic activity toward the pH-universal hydrogen evolution reaction (η₁₀  = 14 mV in 1 m KOH, η₁₀  = 12 mV in 0.5 m H₂ SO₄ , and η₁₀  = 22 mV in 1 m PBS), alkaline oxygen evolution reaction (η₁₀  = 225 mV), and overall water splitting (E₁₀  = 1.49 V) with high mass activity and operational stability. Further reduction endows the material (Pd₂ RuOx-2 h) with a promising alkaline oxygen reduction activity, evidenced by high halfway potential, four-electron selectivity, and excellent poison tolerance. The enhanced catalytic activity is attributed to the rational integration of favorable nanostructures, including 1) the atomically thin nanosheet morphology, 2) the coexisting amorphous and defective crystalline phases, and 3) the multi-component heterostructural features. These structural factors effectively regulate the material's electronic configuration and the adsorption of intermediates at the active sites for favorable reaction energetics.

Beneficial Primary Outcomes of Metabolic Surgery with Changes in Telomere Length and Mitochondrial DNA in Obese Asian Indians with Dysglycemia

INTRODUCTION

Although metabolic surgery has been shown to offer beneficial primary outcome results in obese individuals / obese Type 2 diabetes mellitus (T2DM) patients, there is paucity of information on the underlying mechanisms. In the recent years, estimations of non-invasive molecular parameters viz., telomere length and mtDNA copy number (mtDNAcn) assume significance as robust biomarkers. However, there is lack of evidence about this especially, in the Indian context. To assess the changes in the telomere length and mtDNAcn levels after metabolic surgery in obese Asian Indians with dysglycemia along with routine measurements of anthropometry, glycemic/lipidimic parameters and inflammatory markers.

METHODS

This study is a prospective one-year follow-up study of 16 obese individuals with dysglycemia who underwent metabolic surgery at a tertiary diabetes centre in South India. Telomere length, mtDNAcn, serum adiponectin, glycated haemoglobin and high- sensitivity C-reactive protein (hs-CRP) levels were analysed before surgery and at 6 and 12 months after surgery.

RESULTS

There was a significant reduction in weight (p&lt;0.001), BMI (p&lt;0.001), waist circumference (p&lt;0.001), fasting and postprandial glucose (p&lt;0.05), HbA1c (p&lt;0.001), triglycerides (p&lt;0.05), hs CRP (p&lt;0.05) and increase in serum adiponectin (p&lt;0.05) at 6 and 12 months post-surgery compared to the preoperative status. There was a significant reduction in mtDNAcn (p&lt;0.001) and a significant increase in telomere length (p&lt;0.001) at 6 and 12 months post metabolic surgery.

CONCLUSION

We report an increase in telomere length and decrease in circulatory mtDNA copy number levels at 6 and 12 months post metabolic surgery in obese individuals with T2DM in India.

Metallenes as functional materials in electrocatalysis

2D metals, metallenes, feature exciting opportunities at the forefront of electrocatalysis. We bring to attention metallene preparation techniques and modification strategies for the derivation of highly functional metallenes in key electrocatalytic applications.

Inhalational induction of general anaesthesia for elective caesarean: ethical acceptability in treatment-resistant needle phobia?

We describe the anaesthetic management of a parturient who, due to a severe needle phobia, requested an inhalational induction of general anaesthesia for an elective caesarean section. If general anaesthesia is indicated, conventional practice in the UK is to perform a rapid sequence induction via an intravenous route of drug administration to allow rapid intubation of the trachea. This is because obstetric patients are considered to have a 'full stomach' due to the effects of pregnancy and labour on gastric emptying, and a higher risk of aspiration with consequent maternal and fetal adverse outcomes. Despite a thorough consent process highlighting these significant risks, the patient insisted on an inhalational induction of anaesthesia. We present the case and discuss the ethical dilemma (relating to patient care) in situations in which decisions made by patients deviate from medical recommendations.

Task Analysis of Aircraft Inspection Activities: Methods and Findings

Unless the U.S. commercial aircraft fleet is maintained with high reliability, we cannot be assured of flight safety with an ageing fleet. Maintenance depends upon inspection to be effective, thus the reliability of aircraft inspection is of paramount importance to safety. To provide baseline data on the current inspection activities of commercial aircraft, a task analysis of inspection by commercial carriers was undertaken as part of the Federal Aviation Administration's National Ageing Aircraft Research Program (NAARP). This paper describes the Task Analysis methodology developed, typical results, and some human-system mismatches detected.

Epstein-Barr virus-positive multiple myeloma following an ABO incompatible second renal transplantation

ABO incompatible kidney transplant recipients receive higher dose of immunosuppression. Previous data indicate that the incidence of malignancy is not higher in these patients. Compared to the general population, renal transplant recipients are at 4.4-fold higher risk of developing myeloma. We describe a case of posttransplant multiple myeloma in an ABO incompatible renal transplant recipient of a second graft.

Formulation and Evaluation of in situ Gels Containing Clotrimazole for Oral Candidiasis

Gel dosage forms are successfully used as drug delivery systems to control drug release and protect the medicaments from a hostile environment. The main objective is to formulate and evaluate in situ oral topical gels of clotrimazole based on the concept of pH triggered and ion activated systems. The system utilizes polymers that exhibit sol-to-gel phase transition due to change in specific physico-chemical parameters. A pH triggered system consisting of carbopol 934P (0.2-1.4% w/v) and ion triggered system using gellan gum (0.1-0.75% w/v) along with hydroxylpropylmethylcelluose E50LV was used to prolong the release of clotrimazole (0.1% w/v). Formulations were evaluated for gelling capacity, viscosity, gel strength, bioadhesive force, spreadability, microbiological studies and in vitro release. The use of carbopol as in situ gel forming system was substantiated by the property to transform into stiff gels when the pH was raised, whereas in gellan gum this transformation occurred in the presence of monovalent/divalent cations. Effect of calcium carbonate and other process parameters optimized and found that increase in calcium ions produced stronger gels. The drug content, clarity, and pH of the formulation were found to be satisfactory. The viscosity was found to be in the range 5 to 85 centipoise for the sol, whereas for the gels it was up to 16000 centipoise. The formulation showed pseudoplastic flow with thixotrophy. The maximum gel strength (using texture analyzer) and bioadhesion was found to be up to 6.5 g and 4 g, respectively. The optimized formulations were able to release the drug up to 6 h. The formulation containing gellan gum showed better sustained release compared to carbopol based gels.

Preparation and Evaluation of Nano-vesicles of Brimonidine Tartrate as an Ocular Drug Delivery System

The objective of the present investigation was to design a vesicular formulation of brimonidine tartrate and evaluate its ability to reduce the dosing frequency and improve the therapeutic efficacy of the drug. Nano-vesicles of brimonidine tartrate were prepared by film hydration method. The prepared vesicles were evaluated for photomicroscopic characteristics, entrapment efficiency, in vitro, and ex-in vitro drug release and in vivo intraocular pressure (IOP) lowering activity. The methods employed for preparation of vesicles produced nano vesicles of acceptable shape and size. The in vitro, and ex-in vitro drug release studies showed that there was slow and prolonged release of the drug, which followed zero-order kinetics. The IOP-lowering activity of nano vesicles was determined and compared with that of pure drug solution and showed that the IOP-lowering action of nano-vesicles sustained for a longer period of time. Stability studies revealed that the vesicle formulations were stable at the temperature range of 2-8°C, with no change in shape and drug content. The results of the study indicate that it is possible to develop a safe and physiologically effective topical formulation that is also convenient for patients.

Effect of functional groups on antioxidant properties of substituted selenoethers

Selenoethers attached to functional groups through propyl chain viz., bis(3-carboxypropyl)selenide (SeBA), bis(3-hydroxypropyl)selenide (SePOH) and bis(3-aminopropyl)selenide dihydrochloride (SePAm), have been examined for their ability to inhibit peroxyl radical mediated DNA damage, peroxyl radical scavenging ability and glutathione peroxidase (GPx) like activity. The DNA damage was monitored by gel electrophoresis, bimolecular rate constants for scavenging of model peroxyl radical were determined by pulse radiolysis and the GPx activity was followed by their ability to reduce hydrogen peroxide in the presence of glutathione utilizing NADPH decay and HPLC analysis. Among these compounds, SeBA showed maximum DNA protecting activity and it was also the most efficient in scavenging peroxyl radicals with the highest GPx mimicking activity. Quantum chemical calculations confirmed that SeBA with the highest energy level of HOMO (highest occupied molecular orbital) is the easiest to undergo oxidation and therefore exhibits better radical scavenging, GPx mimicking and DNA protecting activity than SePOH or SePAm.

Re-establishment of erythropoietin responsiveness in end-stage renal failure following renal transplantation

Re-establishment of erythropoietin (EPO) secretion following renal transplantation is poorly understood. The development of sensitive EPO radioimmunoassay has enabled further study of this phenomenon. Forty-one adult patients were studied during the first 16 weeks following renal transplantation. Twenty six received cyclosporin monotherapy and 15 also received prednisolone and azathioprine. Serum creatinine, haemoglobin (Hb), ferritin and EPO were assayed pre-operatively, daily for 1 week, weekly for 1 month, and fortnightly to 16 weeks. An expected EPO value, for any Hb level, was derived by linear regression analysis in 144 patients with iron deficiency anemia. An observed to expected ratio (O/E) was calculated, a value of 1.0 implying appropriate responsiveness. Hb increased from 8.6 +/- 2.0 (SD) to 12.3 +/- 2.1 g/dl (p < 0.001) over 16 weeks, an increase unaffected by ferritin status. Mean EPO concentration increased during the first week with a peak at day 4 (22.1 +/- 13.3 to 44.6 +/- 40.0 mu/ml, p < 0.05), a change apparent only in patients with immediate graft function (24 cases). There was no correlation between EPO and Hb pre-operatively; however a significant inverse relationship was established by week 16 (r = -0.404, p < 0.02). The median O/E ratio (0.22) at baseline increased progressively to 1.0 at 16 weeks (p < 0.001); ratios were significantly greater in the immediate versus delayed function group throughout (p < 0.05). In the former group an O/E ratio of 1.0 was reached at 10 weeks when mean serum creatinine was 142 +/- 48 mumol/l. Patients with poor ongoing renal function (9 cases, serum creatinine > 250 mumol/l at 16 weeks) had impaired Hb recovery (10.1 +/- 1.6 vs 12.7 +/- 2.0 g/dl at 16 weeks, p < 0.05). EPO values were not different in those patients but median O/E ratios were significantly depressed (p < 0.05) throughout, the maximum O/E ratio being 0.75. Recovery of renal function is accompanied by a beneficial Hb response driven by EPO synthesis in the transplant. The O/E ratio provides a useful index to assess EPO responsiveness. Appropriate secretion was achieved during the first 4 months and optimized by immediate and satisfactory graft function.

A comparison of molecular clearance rates during continuous hemofiltration and hemodialysis with a novel volumetric continuous renal replacement system

We developed a continuous, volumetrically controlled veno-venous renal replacement system that can be operated in filtration or dialysis modes. We compared the clearances of substances with a range of molecular weights (MW) in each mode. Ten patients with acute renal failure underwent serial postdilutional hemofiltration and hemodialysis, for 30 min each, in sequence and in randomized order. All were receiving vancomycin for concurrent sepsis. The system incorporated a Filtral 10 AN69 artificial kidney; blood flow rate was 200 ml/min, and dialysate/filtrate flow rate was 25 ml/min. Sieving (SC) and diffusion (DC) co-efficients, for hemofiltration and hemodialysis, respectively, were identical for urea (MW 60; 1.01 +/- 0.05 vs 1.01 +/- 0.07) and creatinine (MW 113; 1.00 +/- 0.09 vs 1.01 +/- 0.06), and clearance equated with dialysate/filtrate flow. There was a modest difference in uric acid clearance (MW 168; SC 1.01 +/- 0.04 vs DC 0.97 +/- 0.04; p < 0.05). Vancomycin (MW 1,800) removal was 19% greater during filtration compared with dialysis (SC 0.87 +/- 0.10 vs DC 0.74 +/- 0.06; p < 0.01). For small solutes, the two modalities were equivalent. Vancomycin clearance was appreciably greater with hemofiltration, which is consistent with a greater potential for convection-based therapy in the removal of uremic and other middle molecules.

Assessment of nutrient intake and associated factors in an Indian elderly population

A group of 420 elderly people (163 women and 257 men with a mean age of 65 years) from urban and rural populations in India were selected for the study. The caloric intake of 93.3% was less than the recommended allowance, the mean daily caloric intake being 1191 kcal in men and 928 kcal in women. Except for calcium, all nutrients were deficient in their diet. Illiteracy (53%), lack of knowledge regarding daily allowances of nutrients (95%), poor economic background (46.7%), and breaking down of joint family system (63%) were possible associated factors examined.

Volumetric control of continuous haemodialysis in multiorgan failure

The authors have developed a system for volumetric control of continuous haemodialysis. The article describes this system and reports its successful use in providing renal support in the intensive care unit to 10 patients with multiorgan failure. In addition to providing effective treatment of uraemia, it permits the precise control of fluid balance in a prospective manner ("dial-up" fluid balance) while reducing nursing workload.

Planning and implementation of microscope work

In modern electronics manufacturing, many of the assembly operations require the use of microscopes. This paper presents measures and suggestions that could help in relieving visual and postural fatigue in microscope work. These measures include the ergonomic design of microscope workstations as well as of microscopes themselves, process changes to minimise use of the microscope, replacement of microscope workstations with television systems, and a training programme for inexperienced operators. The main emphasis in implementing these recommendations was the ergonomic design of microscope workstations; several examples are given.

Breast Cancer Screening Project in Northeast Florida

The American Cancer Society--Duval Unit, in June, 1987, helped organize a community demonstration screening project involving all hospitals and institutions with mammography units in the area. A Northeast Florida Cooperative Breast Cancer Screening Group was formed comprised of physicians and administrators from each institution. A total of 1,200 women agreed to participate in the project and each underwent complete screening including education, instruction in self-examination, physical examination by a physician and mammography as indicated according to ACS guidelines. Of the study group, 1,032 women were eligible for mammography at a participating center, and 628 (61%) underwent a mammogram at no cost to them as instructed. Twenty four (4%) had definite abnormalities which led to biopsy and seven (1%) of them had malignant lesions. The medical community organized to provide breast cancer screening and follow-up with low-cost mammography.