Chemistry

In the current study, bulk tungsten material surfaces are exposed to hydrogen, deuterium, and helium plasmas in the radiofrequency domain (13.56 MHz) at an input power of 250 W using the hollow-cathode configuration. The ejected material is collected on titanium substrates at various distances (from 6 mm up to 40 mm). Therefore, the exposed tungsten materials are investigated for surface changes (blister occurrence, dust formation, or nano-structuration), along with the crystallinity, depending on the plasma’s exposure times (from 30 min up to 120 min for each plasma type). Also, the collected materials are analyzed (morphological, structural, and statistical investigations) for dust and dust film-like appearance. Plasma discharges are analyzed using two methods: optical emission spectroscopy, and single Langmuir probes, to emphasize the nature of the used plasmas (cold discharges, ~2 eV), along with the presence of tungsten emission (e.g., WI 406.31 nm, WI 421.31 nm) during the pla...

In this work we report on the deposition of UV resistant shellac thin films by matrix assisted pulsed laser evaporation (MAPLE). The films obtained starting from a solution of 1-2 wt% shellac in methanol were very smooth and their chemical structure was preserved after the laser transfer. Upon short exposure time (u to 60 min), UV irradiation did not induce significant modifications in the films composition and surface appearance, while upon increasing the irradiation time (240 min) an esterification process of shellac can be observed.

Worldwide, hypoxia-related conditions, including cancer, COVID-19, and neuro-degenerative diseases, often lead to multi-organ failure and significant mortality. Oxygen, crucial for cellular function, becomes scarce as levels drop below 10 mmHg (<2% O2), triggering mitochondrial dysregulation and activating hypoxia-induced factors (HiFs). Herein, Oxygen nanoBubbles (OnB), an emerging versatile oxygen de-livery platform, implies to offer a novel approach to address hypoxia-related pathologies. This review explores OnB oxygen delivery strategies and systems, including diffusion, ultrasound, photodynamic, and pH-responsive nanobubbles. It delves into the nanoscale mechanisms of OnB, elucidating their role in mitochondrial metabolism (TFAM, PGC1alpha), hypoxic responses (HiF-1alpha), and their interplay in chronic pathologies including cancer and neurodegenerative disorders, amongst others. By understanding these dynamics and underlying mechanisms, this article aims to contribute to o...

Background Retinol-binding protein (RBP) is a non-glycosylated protein synthesized by the liver. The role of RBP is to transport retinol (vitamin A) from the liver to the target tissues. RBP is also a sensitive marker of undernutrition. Serum/plasma RBP levels decrease with Vitamin A deficiency, hepatocellular insufficiency, and severe inflammation. Serum/plasma RBP levels increase with renal failure, type-2 diabetes, and steatosis. Methods The immunoassay was developed and validated on the turbidimetric instrument Cobas c501 from Roche Diagnostics. The antibodies against RBP in the assay react with RBP in the sample, and the turbidity formed by formation of antibody-antigen complexes is measured at 340 nm and 700 nm. The analytical sensitivity was tested in a study including 4 samples, analysed in 3 replicates over 3 days using a protocol based on the CLSI guideline EP17. The limit of quantification (LoQ) is defined as the lowest concentration of an analyte that can be reliably det...

Background: -To enhance child health, Indian Child Development Scheme (ICDS) and National Health Mission (NHM) strategized that reinforcement of Infant and Young Child Feeding (IYCF) practices would be a good take off. Anganwadis, where 78% of mothers of children below 6 receive services, can serve as an effective platform for mothers to receive counseling on appropriate breast feeding and complementary foods, in a priority state like Odisha.  Aim: -As a prelude to a detailed intervention, a rapid baseline situational analysis was planned in 4 intervention districts to know about the district specific variations and also the overall IYCF practices in the area. Objective: Assess the IYCF indicators in the districts with focus on feeding practices above 6 months of age. Assess the factors responsible for breast feeding and complementary feeding in the sample Materials and Methods: - Final sample of 600 was chosen using 30 cluster sampling based on proportions of less than 2 years chil...

Wild lingonberries are a traditional source of food in the Nordic countries and an important contributor to economic activity of non-wood forest products in the region. Lingonberries are a rich source of bioactive compounds and can be a valuable contributor to a healthy diet. However, there are few studies available on how the bioactive compounds in lingonberries develop as they ripen. In this investigation, we examined the content of 27 phenolic compounds, three sugars, four organic acids, and 71 volatile organic compounds at five ripening stages. The study showed that, while the highest content of phenolic compounds was found early in the development, the organoleptic quality of the fruits improved as they ripened. From the first to the last stage of development, anthocyanins went from being nearly absent to 100 mg/100 g fw, and there was an increased content of sugars from 2.7 to 7.2 g/100 g fw, whereas the content of organic acids decreased from 4.9 to 2.7 g/100 g fw, and there ...

The development of new fermentative strategies exploiting the potential of different wine-related species is of great interest for new winemaking conditions and consumer preferences. One of the most promising non-conventional approaches to wine fermentation is the combined use of deacidifying and acidifying yeasts. Lachancea thermotolerans shows several other properties besides lactic acid production; among them, high malic acid consumption is of great interest in the production of red wines for avoiding undesirable refermentations once bottled. The combination of a L. thermotolerans strain that is able to consume malic acid with a Schizosaccharomyces pombe strain helps to ensure malic acid elimination during alcoholic fermentation while increasing the final acidity by lactic acid production. To properly assess the influence of this alternative strategy, we developed combined fermentations between specific strains of L. thermotolerans and S. pombe under sequential inoculation. Both ...

Wastewater from tofu (soybean curd) production contains a high organic concentration that might pollute the environment if it is not treated properly. Among the major organic constituents of tofu wastewater are proteins. Degradation of proteins generates ammonia and H2S gases, and if this occurs in an anaerobic digester might hamper the digester’s performance. On the other hand, proteins can potentially be recovered as value-added products. This research aimed to identify protein amounts in different fractions of tofu wastewater, as a basis of designing a process to recover the proteins. Furthermore, the influence of a lower protein concentration to anaerobic digestion of tofu wastewater was calculated. Tofu wastewater was fractionated by gravity settlement and filtration into settleable, suspended, and dissolved fractions. Subsequently, total solids, protein, and COD concentrations of each fraction were analysed. Our results show that tofu wastewater contained 2.9 g-protein/L, equi...

Increasing antimicrobial resistance to the action of existing antibiotics has prompted researchers to identify new natural molecules with antimicrobial potential. In this study, a green system was developed for biosynthesizing gold nanoparticles (BAuNPs) using sage (Salvia officinalis L.) leaf extract bioconjugated with non-toxic, eco-friendly, and biodegradable chitosan, forming chitosan/gold bioconjugates (Chi/BAuNPs). Characterization of the BAuNPs and Chi/BAuNPs conjugates takes place using transmission electron microscopy (TEM), X-ray spectra, Fourier transform infrared (FT-IR) spectroscopy, and zeta potential (Z-potential). The chemical composition of S. officinalis extract was evaluated via gas chromatography/mass spectrometry (GC/MS). This study evaluated the antioxidant and antimicrobial activities of human pathogenic multidrug-resistant (MDR) and multisensitive (MS) bacterial isolates using the agar diffusion method. Chi/BAuNPs showed inhibition of the MDR strains more eff...

This paper presents the process optimization for heterogeneous catalysts transesterification of refined cottonseed oil catalyzed by calcium oxide (CaO) and magnesium oxide (MgO) impregnated on saw dust ash (SDA) using response surface methodology central composite design (RSMCCD). The five transesterification process variables studied are: catalyst concentration (4-8 wt% oil), methanol/oil molar ratio (4:1-8:1), reaction temperature (45-85oC), reaction time (3-5h) and agitation speed (200-300rpm). From this study, it was found out that reaction temperature gave the most significant effect on the yield of fatty acid methyl ester (FAME), followed by methanol/oil molar ratio. There were also significant interaction effects between catalyst concentration and methanol/oil molar ratio, catalyst concentration and agitation speed, methanol/oil molar ratio and reaction temperature, methanol/oil molar ratio and reaction time, methanol/oil molar ratio and agitation speed, reaction time and agi...

Considerable effort has been devoted to the development of first-row transition-metal catalysts containing redox-active imino-pyridine ligands that are capable of storing multiple reducing equivalents. This property allows abundant and inexpensive first-row transition metals, which favor sequential one-electron redox processes, to function as competent catalysts in the concerted two-electron reduction of substrates. Herein we report the syntheses and characterization of a series of iron complexes that contain both π-donating thiolate and π-accepting (α-imino)-N-heterocycle redox-active ligands, with progressively larger N-heterocycle rings (imidazole, pyridine, and quinoline). A cooperative interaction between these complementary redox-active ligands is shown to dictate the properties of these complexes. Unusually intense charge-transfer (CT) bands, and intraligand metrical parameters, reminiscent of a reduced (α-imino)-N-heterocycle ligand (L), initially suggested that the electron...

Metastable Mn-peroxo species are proposed to form as key intermediates in biological oxidation reactions involving O(2) and C-H bond activation. The majority of these have yet to be spectroscopically characterized, and their inherent instability, in most cases, precludes structural characterization. Cysteinate-ligated metal-peroxos have been shown to form as reactive intermediates in both heme and nonheme iron enzymes. Herein we report the only examples of isolable Mn(III)-alkylperoxo species, and the first two examples of structurally characterized synthetic thiolate-ligated metal-peroxos. Spectroscopic data, including electronic absorption and IR spectra, and ESI mass spectra for (16)O vs (18)O-labeled metastable Mn(III)-OOR (R = (t)Bu, Cm) are discussed, as well as preliminary reactivity.

Understanding the metal ion properties that favor O-H bond formation versus O-H bond cleavage, should facilitate the development of catalysts tailored to promote a specific reaction, e.g., C-H activation or H2O oxidation. The first step in H2O oxidation involves the endothermic cleavage of a strong O-H bond (BDFE= 122.7 kcal/mol), and is promoted both by binding the H2O to a metal ion, and by coupling electron transfer to proton transfer (PCET). Details regarding how a metal ion's electronic structure and ligand environment can tune the energetics of M(HO-H) bond cleavage is part of the focus of the study herein. The synthesis and characterization of an Fe(II)-H2O complex, [FeII(OMe2N4(tren))(H2O)]+ (1), that undergoes PCET (66 mV/pH) in H2O to afford a rare example of a monomeric Fe(III)-OH (g= 8.79, 5.16, 4.23), [FeIII(OMe2N4(tren))(OH)]+ (7) is described. High-spin 7 is also reproducibly generated in solution via the addition of 240 equiv of H2O to a MeCN solution of oxo-brid...

Superoxide reductases (SORs) are nonheme iron-containing enzymes that reduce HO 2 to H 2 O 2 . Exogenous substrates such as N \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \setlength{\oddsidemargin}{-69pt} \begin{document} \begin{equation*}_{3}^{-}\end{equation*}\end{document} and CN − have been shown to bind to the catalytic iron site of SOR, and cyanide acts as an inhibitor. To understand how these exogenous ligands alter the physical and reactivity properties of the SOR iron site, acetate-, azide-, and cyanide-ligated synthetic models of SOR have been prepared. The x-ray crystal structures of azide-ligated [Fe III (S Me2 N 4 (tren))(N 3 )] + (3), dimeric cyanide-bridged ([Fe III (S Me2 N 4 (tren))] 2 -μ-CN) 3+ (5), and acetate-ligated [Fe III (S Me2 N 4 (tren))(OAc)] + (6) are described, in addition to x-ray absorption spectrum-derived and preliminary crystallographic st...