Form Of Oxide Research Articles

Hyperbilirubinemia and transaminitis in hepatitis A: case report on early remission through ayurveda interventions

Hepatitis A is a common cause for acute hepatitis and jaundice. It is mostly self-limiting requires no or suppurative treatment and very rare cases prolong jaundice, liver failure and death. Prolonged jaundice types of cases are mostly going to folk healers and herbalist. Ayurveda has no recordable evidence of course of treatment in Hepatitis A. Therefore, this case paper will be a notable evidence for Ayurveda in hepatitis A. A 43-year female came to hospital with an one week history of lethargy, anorexia, weight loss and yellow discoloration of urine. The patient has Hepatitis A (HAV) IgM antibody positive with other viral profile negative and elevated bilirubin(6.28mg/dl) and high transaminase (SGOT-824U/L and SGPT 1263 U/L). Arogyavardhini Vati, Liv 52Hb and Phalatrikadi Kwatha were administrated in its standard doses as these regimen have Agnideepak(Carminative), Srotosothaka (channel purifier), Mrudu virechana ( Mild purgative)properties, but no signicant change in liver function test . then ( Siddha Makardwaja Rasa) is added to reduce liver inflammation and possible involvement of cholangitis. The physical strength , appetite was normalised along with normalisation of bilirubin and liver transaminase within three weeks of the therapy. The combination of therapy may reduce the bile acid cytotoxicity of bile and, possibly, decrease of the concentration of hydrophobic bile acids in the cholangiocyte. As Siddha Makardwaja special is in metallic oxide form (Au/HgO), it may be acts as an anti-inflammatory drug by reducing pro inflammatory cytokine expression, blocking leucocyte adhesion and decreasing oxidative stress due to infection. This case report is preliminary evidence for further stresses the significance of Siddha Makardwaja Rasayana along with other Ayurveda formulations in early remission of high bilirubin and liver transaminase in Hepatitis A infection. This treatment regimen can be used for local epidemic of Hepatitis A for appropriate Ayurveda management after randomised clinical trial.

Effect of 60Co Irradiation on Boehmite Dissolution in Caustic Solutions.

Here, we examine how radiation impacts the dissolution behavior of boehmite by subjecting dry nanoparticles of different sizes to 60Co γ radiation and subsequently analyzing their dissolution behavior in caustic solutions as a function of temperature. The measured kinetics show that irradiation with an amount 228.24 Mrad significantly slows the dissolution rate, particularly for smaller sizes at lower temperatures. Specifically, the temperature-dependent dissolution rates of irradiated 20 nm boehmite versus pristine material in 3 M NaOH solutions were several times lower (e.g., rate constant of 0.026 vs 0.075 h-1 at 60 °C), with an apparent activation energy 40 kJ mol-1 higher. Although various imaging techniques and X-ray diffraction measurements consistently revealed no obvious differences between pristine and irradiated samples, after irradiation significant binding energy shifts were detected in the X-ray photoelectron Spectroscopy peaks of Al 2p and O 1s, and a change in their relative intensities indicated a lower O/Al ratio. This suggests that γ-irradiation may stabilize boehmite particle surfaces by driving their chemistry and structure toward more stable aluminum oxide forms. This finding may help explain slower dissolution rates of boehmite in nuclear waste and may be useful for the development of more robust predictive models and effective strategies for waste processing.

Geotechnical, Mineralogical, Petrographic and Microstructural Characterization of Two Lateritic Gravels from Congo

The recovery of lateritic gravel contributes to the reduction of road construction costs and environmental impact. These materials are of particular interest in road construction because of their abundance, especially in tropical countries, as in the case of Congo. The results obtained on the soils of ʽʽTSANGA and TSIAKIʼʼ show an identical appearance of the two particle size curves, with more fines in the TSANGA sample. Both soils are moderately plastic and their properties predispose them to mechanical treatment (TSIAKI soils) and hydraulic binders (TSANGA soils). The lateritic gravels of TSIAKI can be used as road sub-base for medium traffic while those of TSANGA as sub-base for low traffic. The geotechnical properties of the two samples differ due to the mineralogy, petrography and microstructure which vary from one deposit to another. The SEM microstructure study shows two matrices completely made of kaolinite and the matrix facies are cemented by hematite. X-ray microscopy and SEM allowed the differentiation of goethite and hematite to distinguish the two forms of iron oxides. The TSIAKI soil has a normal iron oxide content (mainly goethite), and has less quartz and kaolinite, which could justify its high CBR index.

Microfluidic sensor using pH gradient with hybrid magnetoliposomes containing laccase immobilized nanocrystals.

A method using pH gradient to modify the phospholipid dissociation has been developed using hybrid magnetoliposomes with encapsulated enzyme laccase, which has been immobilized on hydrophilic magnetic nanocrystals (PAA-MNCs) retained in the reaction/detection zone of a microfluidic system. The hybrid magnetoliposomes act as micro containers, providing the safe transfer of the enzyme to the reaction/detection site, where it is retained, and preconcentration of the enzyme in this placeoccurs, which improves the system's sensitivity. The use of pH change involves the lack of external molecules to release the encapsulated materials. The laccase-mediated redox oxidation of the fluorescent substrate 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS) to form its non-fluorescent oxide form has been used as the indicator reaction. The method was applied to determine potential laccase inhibitors in beverages and fruits. The study of the inhibitory effect has focused on compounds that follow different mechanisms: cysteine, malic acid, and fumaric acid. The dynamic ranges of the calibration graphsof these compoundswere between 0.05-100, 0.02-100, and 0.1-100μmol L-1, respectively. The detection limits have been established between 6 and 30nmol L-1, and the precision expressed as the percent of relative standard deviation (RSD%) was between 2.5 and 5.1%. The overall microfluidic system showed a sampling frequency of 8h-1. The method has been applied to determine fumaric acid as a laccase inhibitor in several juice samples (apple, pear, and grape), with recovery values between 85 and 101%. The results were comparable to those obtained using a LC reference method.

Silver-Tungsten induced codeposition: Influence of pH and carboxylic acid form in a DMH-based electrolyte

Silver-tungsten coatings were successfully electrodeposited on platinum and copper substrates from a non-toxic 5.5-dimethylhydantoin electrolyte at low pH and two different carboxylic acid forms: citrate or tartrate. Tungsten contents remain at low levels compared to former works, but close to the values considered as optimal for functional properties without having to recourse to controversial substances such as thiourea. Electrochemical studies by linear sweep voltammetry allow to distinguish two typical behaviors and give interesting insight into the induced codeposition mechanism. Silver-tungsten codeposition only occurred at pH 2.0 and 3.5 using citrates and at pH 2.0 using tartrates, corresponding to the forms H3Cit, H2Cit-2, and H2Tar, respectively. No silver-tungsten reduction was possible with less than two protonated carboxyl groups on either tartrate or citrate ions. Separate silver and tungsten lattice are both present in the resulting alloy. Grain and crystallite sizes were observed by SEM. XPS investigations show that for our low W content alloys, silver is found to be metallic whereas tungsten is present in oxide form. The carbon peaks and also gaps between peaks when N is absent indicate that citrates are present in the coating, unlike DMH.

Strength gradient in impact-induced metallic bonding

Solid-state bonding can form when metallic microparticles impact metallic substrates at supersonic velocities. While the conditions necessary for impact-induced metallic bonding are relatively well understood, the properties emerging at the bonded interfaces remain elusive. Here, we use in situ microparticle impact experiments followed by site-specific micromechanical measurements to study the interfacial strength across bonded interfaces. We reveal a gradient of bond strength starting with a weak bonding near the impact center, followed by a rapid twofold rise to a peak strength significantly higher than the yield strength of the bulk material, and eventually, a plateau covering a large portion of the interface towards the periphery. We show that the form of the native oxide at the bonded interface—whether layers, particles, or debris—dictates the level of bond strength. We formulate a predictive framework for impact-induced bond strength based on the evolution of the contact pressure and surface exposure.

Enhanced adsorption of Pb(II) ions using a magnetic mesoporous molecular sieves derived from coal fly ash and Nano-Fe3O4 particles

The synthesis of high-performance adsorption materials from coal fly ash presents a promising approach to mitigating environmental pollution in wastewater treatment processes. A novel magnetic mesoporous molecular sieve (MMS) was synthesized through hydrothermal methods utilizing coal fly ash and nano-Fe3O4 particles. The resultant MMS was characterized using XRD, FT-IR, SEM, TEM, and BET analysis. The adsorption performance of MMS for Pb(II) was evaluated by examining thermodynamic and adsorption models. The results show that MMS exhibited mesoporous structures with embedded Fe3O4 nanoparticles, possessing a surface area of 22.94 m2/g and a pore size of 28.47 nm, favorable for applications in aqueous adsorption. The adsorption behavior of Pb(II) onto MMS adhered well to both pseudo-first-order kinetic model and Langmuir isotherm, with a maximum adsorption capacity of 236.97 mg/L. Further insights into the adsorption mechanism were provided by zeta potential and XPS analysis, which revealed that lead is effectively adsorbed onto MMS, with the lead existing predominantly in the form of oxides on the MMS surface. The adsorption process was primarily governed by physical adsorption, accompanied by chemical adsorption. This study presents an innovative approach to converting coal fly ash into highly efficient magnetic adsorbents, thereby offering a sustainable solution for wastewater treatment.

Understanding Trace Iron and Chromium Incorporation During Gibbsite Crystallization and Effects on Mineral Dissolution.

Incorporation of pollutants, e.g., heavy metals, or critical elements, e.g., lithium, as impurities in mineral phases can significantly affect their mobility or sequestration in the environment. Even when present at low concentrations, impurities can alter the solubility and reactivity of the host mineral. In this study, we investigate the incorporation of trace amounts of iron (Fe3+) and chromium (Cr3+) during the crystal growth of the aluminum (Al3+) hydroxide, gibbsite, a major component of bauxite ores, an important soil mineral, and a dominant mineral phase in stored radioactive wastes. Using a comprehensive suite of analytical techniques, we show that both Cr3+ and Fe3+ can be incorporated into the gibbsite lattice during coprecipitation by replacing Al3+ in octahedral sites. These small amounts are consistent with limited to no structural isomorphism shared between Al3+ and Cr3+/Fe3+ hydroxide precipitates, nor room temperature miscibility of their isostructural M2O3 oxide forms, in contrast with oxyhydroxide forms where Al3+ and Fe3+ share similar structural topologies. Despite the limited uptake of Cr3+/Fe3+, we show that these impurities have significant implications for gibbsite dissolution behavior. The limited uptake of Cr3+/Fe3+ (e.g. 0.43% Cr3+ and 0.4% Fe3+), we show that these impurities have significant implications for gibbsite dissolution behavior and subsequent reactivity in complex environments.

CO2 reduction by chars obtained by pyrolysis of real wastes: Low temperature adsorption and high temperature CO2 capture

In this work, the carbon dioxide capture of waste derived chars was investigated. The char samples were obtained by pyrolysis of municipal plastic waste, biomass and sewage sludge from agriculture at 400, 600 and 900 °C in nitrogen atmosphere. For further experiments, chars with a grain size between 0.315 mm and 1.50 mm were investigated. The CO2 uptake capacity of samples was tested at 40 °C through a 10 adsorption-desorption cycles using a mixture of 70 % nitrogen and 30 % carbon dioxide. The CO2 uptake capacity of the reference activated carbon was 3.71–3.90 mmol CO2/g, while that of the waste derived char samples varied between 0.76–2.33 mmol CO2/g depending on the pyrolysis temperature and the raw materials. Chars with large specific surface area obtained at 900 °C had the highest CO2 uptake capacity. Char obtained from municipal plastic waste at a pyrolysis temperature of 900 °C has the largest specific surface area. The biomass and sewage sludge derived chars contained alkali metals and earth metals in oxide form, therefore the possibility of their application for carbonization-calcination cycles was also investigated. In case of the high-temperature tests, the CO2 uptake took place at 750 °C, while the release at 900 °C. During the 10 cycles test, significant decrease in capacity up to the 5th cycle was found. The capacity of char obtained from agricultural sewage sludge was 18.68 mmol CO2/g in the first cycle, which decreased drastically to 2.88–2.96 mmol CO2/g after the 5th cycle.

Decarbonization of Nitrogen Fertilizers, from Production to Runoff: A Policy Memo

Decarbonization of agriculture is critical to reshaping the U.S. economy as climate-resilient and less carbon-intensive. Decarbonizing nitrogen fertilizers specifically is increasingly important for the U.S. to achieve its climate targets while feeding a growing population in a changing climate, as around 5% of global greenhouse gas emissions result from nitrogen fertilizers alone. Carbon dioxide equivalent emissions from fertilizer come from non-renewable energy use, chemical processes, transportation, and on-farm applications. These emissions typically take the form of carbon dioxide or nitrous oxide, potent greenhouse gasses. To reduce emissions from nitrogen fertilizers, the United States Department of Agriculture (USDA), Environmental Protection Agency (EPA), and Department of Energy (DOE) should 1) create federal regulations for nitrogen fertilizer use, 2) provide financial incentives for farmers transitioning to less-intensive nitrogen fertilizer use, and 3) create a research grant solicitation focused on regional methods for reducing nitrogen fertilizer use and the creation of green hydrogen.

A Study on the Potential for the Application of Peanut Shells as a Reducer in the Process of Metal Recovery from Metallurgical Slags

Copper production technology is a complex process consisting of many stages. The combination of pyrometallurgical and hydrometallurgical stages, on the one hand, complicates production while, on the other hand, allowing for a relatively selective separation of intermediate or waste materials that can be subjected to the process of recovery of useful components. Materials of this type are characterised by a much higher copper content relative to the ore material. On the other hand, due to the oxide form, reduction processes are used in which coke is mainly applied. Reduction of the unfavourable phenomenon of CO2 emissions, in this case, can be performed through the use of bioreducers, which are characterised by an inert carbon footprint since the generation of carbon dioxides is the same as its absorption at the stage of vegetation and growth. In this paper, the topic of determining the feasibility of using selected bioreducers, such as peanut shells, to verify their suitability in the process of reducing copper oxides as well as the impact on the working components of the laboratory reactor in which the process is carried out are discussed. In this case, raw materials with a composition similar to the that of slags produced at the copper production stage in a flash furnace were tested for reduction. The results referring to reducing lead and copper contents above 88% Pb and 98% Cu indicate the great potential of this type of bioreducer. An additional advantage is the relatively wide availability of peanut resources. The effects of the copper reduction time on the degree of decopperisation performed with a constant reducer addition at 1300 °C were studied in this paper. Following 1 h of the process, the copper content in the slag was 0.78 wt%, while the longer process duration resulted in a copper fraction of 0.19 wt%. Considering lead, its content was 0.33 wt% after the reduction process.

Heteronuclear Fe-Mn Cyclopentadienyl Complexes Supported on Boehmite. Thermochemistry and Thermodynamics of their Decomposition

Boehmite samples with compounds of the composition (C5H5)2FeMnX2(μ-CO)n, where X=Cl, Br and n=1.2, precipitated at room temperature from tetrahydrofuran solutions and then heated in an air flow up to 873 K were obtained and characterized using X-ray diffractometry, infrared Fourier spectroscopy, electron magnetic resonance and temperature-programmed desorption methods. It was shown that the thermal decomposition of these compounds applied to the boehmite samples in the range from room temperature to 873 K occurs stepwise and consists of at least two stages. The first stage of thermal decomposition occurs in the range of 453–753 K, and the second – in the range of 813–843 K. The XRD data show that when calcining at 873 K the boehmite samples with the applied compounds of the above composition and containing these compounds less than 10 wt.%, the diffraction patterns show only reflections characteristic of poorly crystallized aluminum oxide. However, the electron paramagnetic resonance (EPR) spectra of these samples clearly show intense signals characteristic of superpara/ferromagnetic particles of iron and manganese oxides, as well as EPR signals from isolated Fe3+ substituting Al3+ ions in the aluminum oxide structure. EPR spectra most of the iron and manganese is stabilized on the surface of poorly crystallized aluminum oxide in the form of nanostructured iron and manganese oxides.

Recycling of spent heat pack towards Fe-Fe3O4@NC catalyst for ORR in direct methanol fuel cells and Al-air batteries

The effective repurposing of waste materials is crucial for sustainable development. The widespread use of disposable iron-based chemical warmers (IBCW) generates substantial solid waste annually. In this study, IBCWs were repurposed as raw materials to synthesize different electrocatalyst composites comprising metallic and oxide forms of iron embedded in nitrogen-doped carbon (NC). The composites were evaluated as oxygen reduction reaction (ORR) catalysts. The optimized Fe-Fe3O4@NC demonstrated enhanced ORR kinetics, with an onset potential of 0.92 V and a half-wave potential of 0.86 V vs. RHE. As an air cathode for direct methanol fuel cell (DMFC), Fe-Fe3O4@NC achieved a power density of 33.3 mW cm−2 at 88 mA cm−2, demonstrating its practical applicability. Additionally, a quasi solid-state aluminium-air battery (SAAB) was assembled using this catalyst as the air cathode with a PVA-KOH gel electrolyte and the separator. The quasi SAAB exhibited an open circuit voltage (OCV) of 1.46 V, a power density of 40 mW cm-2, and good rate capability compared to Pt/C. The combined effect of metallic and oxide iron with nitrogen doping enhances the overall catalytic activity. This study demonstrates that IBCWs can be effectively transformed into valuable catalysts for renewable energy applications, enabling clean and sustainable utilization of waste materials.

Effects of inhaled nitric oxide on endothelial function in patients with ischemic stroke

BACKGROUND: A crucial pathogenetic link in the development of stroke is the deterioration of endothelial function, which is a pathological condition characterized by an imbalance between endothelium-dependent relaxing and constricting factors. An example of an endothelium-dependent relaxing factor is nitric oxide, a substance synthesized by the body’s cells that has a vasodilating, antithrombogenic, anti-inflammatory, and antiproliferative effect. Studies have shown the neuroprotective function of inhaled nitric oxide after ischemia; however, determining the minimum effective dose of inhaled nitric oxide in patients who have suffered an acute cerebrovascular accident remains challenging. AIM: To analyze the protective effect of exogenous nitric oxide using the TIANOX device on the vascular endothelium in patients who have had an ischemic stroke in the early and late recovery period during medical rehabilitation. MATERIALS AND METHODS: The study involved 21 patients (10 people in the main group, 56.9±8.9 years old, 11 people in the control group, 57.2±8.8 years old) in the early or late recovery period after an ischemic stroke. Patients in the main group underwent an individual medical rehabilitation program and a course of 8–10 inhalations of a gas mixture with nitric oxide at 20 ppm for 20 minutes. Those in the control group underwent an individual rehabilitation course without nitric oxide therapy. Flow-dependent vasodilation of the brachial artery was evaluated to assess endothelial function. RESULTS: In the main group, a statistically insignificant (p 0.05) increase was found in the diameter of the brachial artery (3.68±0.64 mm), whereas in the control group, this indicator at rest during repeated diagnostics was less than the initial one (3.09±0.87 mm). During repeated diagnostics, the average endothelial shear velocity in patients of the control group increased from 141.53±52.62 to 159.3±82 versus from 143.17±43.53 to 143.48±46.37 in the main group; however, the results were not statistically significant (p=0.753). CONCLUSION: The increase in the diameter of the brachial artery during flow-dependent vasodilation in patients in the main group may indicate a prosthetic effect of the exogenous form of nitric oxide when using the Tianox device on the vascular endothelium, owing to the possibility of depositing nitric oxide in the body. To confirm the obtained data, a larger sample size of patients is critical in order to further divide the groups of patients into early and late recovery periods after ischemic stroke.

Endogenous silicon-activated rice husk biochar prepared for the remediation of cadmium-contaminated soils: Performance and mechanism

Biochar is widely used for the remediation of heavy metal-contaminated soils. However, pristine biochar generally has limited active functional groups and adsorption sites, thereby exhibiting low immobilization performance for heavy metals. In addition to carbon (C), silicon (Si) is another common macro-element present in rice husk biochar, but it often exists in the form of amorphous oxide and therefore contributes little to the adsorption performance for heavy metals. The transformation of amorphous Si oxide to dissolved silicate through a precipitation effect can significantly improve its heavy metal immobilization capability. Herein, the amorphous Si oxide in rice husk biochar was activated by sodium hydroxide and then the dissolved silicate was immobilized by calcium salt. The as-synthetized Si-activated biochar was used to remediate cadmium (Cd)-contaminated soils. The results indicated that Si-activated rice husk biochar could reduce Cd migration and environmental risks by the transformation from exchangeable Cd into carbonate-bound and residual Cd. With increasing Ca: Si molar ratio, the content of CaCl2 and H2O-extractable Cd exhibited a decreasing trend. Moreover, a higher addition amount of Si-activated biochar improved the Cd immobilization efficiency. The application of 1.0% Ca/Si molar ratio of 2: 2 Si-activated rice husk biochar decreased the CaCl2-Cd and H2O-Cd concentration by a maximum of 83.7% and 90.5% compared with pristine rice husk biochar, respectively. The present work proposes an approach for highly efficient remediation of Cd-polluted soils by biochar.

Optimization of pure elemental and oxide-based shielding materials for cost

A common aspect to shielding material research is the combination of high atomic number inclusions with binders although the costs of the inclusions will vary with chemical form and have associated density and atomic number dependencies on attenuation properties. As most metals are cheaper in their oxide forms (sometimes drastically) we considered oxide forms to substantially reduce potential cost. This study then investigates the combined shielding and cost optimization of pure elemental and oxide-based shielding materials as well as steel, water and concrete. This focus on shielding effectiveness per cost and weight basis also incorporates contributions from scattered radiation in the form of radiation buildup for these comprehensive materials. In this sense, we define a new metric which incorporates cost, weight and scatter radiation for assessing shielding material attractiveness. We used MicroShield to calculate the shielding ability of each material. Our findings revealed that water, concrete, and lead demonstrated superior performance in terms of cost-effectiveness. This research contributes to the understanding of affordable and efficient shielding materials and has implications for industries reliant on radiation protection, such as nuclear power generation, medical imaging, and space exploration.

Exogenous deferoxamine mesylate suppresses iron-dependent ferroptosis in postharvest fruit rot of blueberry caused by Alternaria alternata and Fusarium fujikuroi

Plant development relies heavily on regulated cell death, which is crucial for specific plant responses to biological stresses. Ferroptosis, an iron-dependent, oxidative, and non-apoptotic cell death form, has been recently discovered in animal cells. In this study, we investigated whether a ferroptosis-like process could be relevant to cell death in postharvest fruit rot of blueberry caused by Alternaria alternata and Fusarium fujikuroi. The results showed that deferoxamine mesylate and glutathione (GSH) treated fruit showed enhanced disease resistance with lower lesion areas, whereas an opposite result was observed in hydrogen peroxide (H2O2) treatment, indicating that intracellular ferroptosis might exist in the fungal infected blueberry fruit. Compared to control, deferoxamine mesylate or GSH treatment improved chlorophyll fluorescence parameters, which contributed to the stability of photosynthesis. In terms of ferroptosis pathway in the adjacent area of infected fruit, deferoxamine mesylate suppressed an iron-dependent cell death pathway that was characterized by depletion of H2O2 and MDA and accumulation of GSH, as well as the reduction of ferrous ions and total iron ions. Meanwhile, deferoxamine mesylate could effectively delay the decrease rate of unsaturation value and key phospholipids of fungi infected fruit during storage, which possibly maintained the integrity of cell membrane. Due to the serious rot of the lesion area, the peroxidation of membrane lipids was severe, accompanied by metabolic disorders. These combined results demonstrated that deferoxamine mesylate treatment could reduce Fenton reaction by chelating Fe2+ and avoid excessive accumulation of reactive oxygen species (ROS), suppress iron-dependent ferroptosis, thereby maintaining fruit quality and reducing postharvest diseases.

Antibacterial and cytocompatible silver coating for titanium Boston Keratoprosthesis.

The Boston Keratoprosthesis (BKPro) serves as a medical solution for restoring vision in complex cases of corneal blindness. Comprising a front plate made of polymethylmethacrylate (PMMA) and a back plate of titanium (Ti), this device utilizes the beneficial biomaterial properties of Ti. While BKPro demonstrates promising retention rates, infection emerges as a significant concern that impacts its long-term efficacy. However, limited research exists on enhancement of BKPros through intrinsic infection-preventing mechanisms. In this regard, metal ions, especially the well-known Ag+ ions, are a promising alternative to obtain implants with innate antibacterial properties. However, little information is available about the effects of Ag in corneal tissue, especially within human corneal keratocytes (HCKs). In this work, an electrodeposition treatment using a constant pulse is proposed to attach Ag complexes onto rough Ti surfaces, thus providing antibacterial properties without inducing cytotoxicity. Complete physicochemical characterization and ion release studies were carried out with both control and Ag-treated samples. The possible cytotoxic effects in the short and long term were evaluated in vitro with HCKs. Moreover, the antibacterial properties of the silver-treated surfaces were tested against the gram-negative bacterial strain Pseudomonas aeruginosa and the gram-positive strain Staphylococcus epidermidis, that are common contributors to infections in BKPros. Physicochemical characterization confirmed the presence of silver, predominantly in oxide form, with low release of Ag+ ions. Ag-treated surfaces demonstrated no cytotoxicity and promoted long-term proliferation of HCKs. Furthermore, the silver-treated surfaces exhibited a potent antibacterial effect, causing a reduction in bacterial adhesion and evident damage to the bacterial cell walls of P. aeruginosa and S. epidermidis. The low release of Ag+ ions suggested reactive oxygen species (ROS)-mediated oxidative stress imbalance as the bactericidal mechanism of the silver deposits. In conclusion, the proposed electrodeposition technique confers antibacterial protection to the Ti backplate of BKPro, mitigating implant-threatening infections while ensuring non-cytotoxicity within the corneal tissue.

Synthesis and characterization of nickel and molybdenum catalysts supported on alumina derived from bauxite

In this study, a natural ore (bauxite), which is characterized by its high content of various aluminum minerals, such as gypsite, , bohmite, and diaspore, AlO(OH), was used to obtain alumina ( ), which was used as a support for the catalyst. The components of the ore were studied using multiple techniques, such as The X-ray energy dispersion (EDX) technique, X-ray diffraction (XRD) and X-ray fluorescence (XRF) technology. Then, undesirable components that negatively affect the behavior of the prepared catalyst were removed, such as carbonates, iron, and amorphous silica, and then aluminum oxide (alumina) was prepared from the ore using a series of chemical treatments. Then the mixed catalyst consisting of (nickel/molybdenum) carried on alumina was prepared, its properties were studied, and its components were identified by measuring energy dispersion with X-rays (EDX) and ensuring the extent of its thermal stability by conducting a thermal analysis measurement. Gravimetric analysis (TGA), differential thermal analysis (DTA), measurement of the surface area of ​​the prepared catalyst (BET), scanning electron microscope (SEM) measurement, as well as X-ray diffraction (XRD) and X-ray fluorescence (XRF) measurements to identify the percentages of metals, and then estimating the percentage of these elements in their oxide form. KEY WORDS: Catalyst, Bauxite, Nickel, Molybdenum Bull. Chem. Soc. Ethiop. 2024, 38(6), 1715-1724. DOI: https://dx.doi.org/10.4314/bcse.v38i6.17

Electrodeposition of actinides: Optimization of deposition parameters by chronoamperometric studies

To quantify alpha-emitting radionuclides by alpha spectrometry, it is necessary to prepare a thin and uniform alpha source on a suitable substrate. Electrodeposition is the most used electrochemical technique for this purpose. In order to better understand the electrochemical process carried out in the electrodeposition of actinides, in particular the selection of the current densities applied, a chronoamperometric study of the electrodeposition of actinides (Th, U, Pu, Am and Cm), in three different electrolytes (Na2SO4/H2SO4, NH4NO3, NaF) using stainless steel and platinum as cathode and anode, respectively, is presented. The corresponding polarization curves (potential vs. current density), characteristic for each electrolyte and actinide used, were constructed from the chronoamperometric data. The limiting diffusion current as well as the minimum current necessary for the electrodeposition process to take place were determined. To achieve a quantitative electrodeposition of actinides, a balance between OH− production and the thickness of the OH− layer formed near the cathode must be reached. These parameters are controlled by the electrolyte used and the current density applied to the electrochemical system. Actinides were electrodeposited mainly in the form of oxides, according to Raman spectroscopy results.