Poly(Vinyl Alcohol)/Poly(Acrylic Acid) Gel Polymer Electrolyte Modified with Multi-Walled Carbon Nanotubes and SiO2 Nanospheres to Increase Rechargeability of Zn-Air Batteries.

Zn-air batteries (ZABs) are a promising technology; however, their commercialization is limited by challenges, including those occurring in the electrolyte, and thus, gel polymer electrolytes (GPEs) and hydrogels have emerged as substitutes for traditional aqueous electrolytes. In this work, PVA/PAA membranes were synthesized by the solvent casting method and soaked in 6 M KOH to act as GPEs. The thickness of the membrane was modified (50, 100, and 150 µm), and after determining the best thickness, the membrane was modified with synthesized SiO2 nanospheres and multi-walled carbon nanotubes (CNTs). SEM micrographs revealed that the CNTs displayed lengths of tens of micrometers, having a narrow diameter (95 ± 7 nm). In addition, SEM revealed that the SiO2 nanospheres had homogeneous shapes with sizes of 110 ± 10 nm. Physicochemical experiments revealed that SiO2 incorporation at 5 wt.% increased the water uptake of the PVA/PAA membrane from 465% to 525% and the ionic conductivity to 170 mS cm-1. The further addition of 0.5 wt.% CNTs did not impact the water uptake but it promoted a porous structure, increasing the power density and the stability, showing three-times-higher rechargeability than the ZAB operated with the PVA/PAA GPE.

Tutton salt (NH4)2Zn(SO4)2(H2O)6: thermostructural, spectroscopic, Hirshfeld surface, and DFT investigations.

CONTEXT: Ammonium Tutton salts have been widely studied in recent years due to their thermostructural properties, which make them promising compounds for application in thermochemical energy storage devices. In this work, a detailed experimental study of the Tutton salt with the formula (NH4)2Zn(SO4)2(H2O)6 is carried out. Its structural, vibrational, and thermal properties are analyzed and discussed. Powder X-ray diffraction (PXRD) studies confirm that the compound crystallizes in a structure of a Tutton salt, with monoclinic symmetry and P21/a space group. The Hirshfeld surface analysis results indicate that the main contacts stabilizing the material crystal lattice are H···O/O···H, H···H, and O···O. In addition, a typical behavior of an insulating material is confirmed based on the electronic bandgap calculated from the band structure and experimental absorption coefficient. The Raman and infrared spectra calculated using DFT are in a good agreement with the respective experimental spectroscopic results. Thermal analysis in the range from 300 to 773 K reveals one exothermic and several endothermic events that are investigated using PXRD measurements as a function of temperature. With increasing temperature, two new structural phases are identified, one of which is resolved using the Le Bail method. Our findings suggest that the salt (NH4)2Zn(SO4)2(H2O)6 is a promising thermochemical material suitable for the development of heat storage systems, due to its low dehydration temperature (≈ 330 K), high enthalpy of dehydration (122.43 kJ/mol of H2O), and hydration after 24 h. METHODS: Computational studies using Hirshfeld surfaces and void analysis are conducted to identify and quantify the intermolecular contacts occurring in the crystal structure. Furthermore, geometry optimization calculations are performed based on density functional theory (DFT) using the PBE functional and norm-conserving pseudopotentials implemented in the Cambridge Serial Total Energy Package (CASTEP). The primitive unit cell optimization was conducted using the Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithm. The electronic properties of band structure and density of states, and vibrational modes of the optimized crystal lattice are calculated and analyzed.

Effect of the estrous cycle on zinc transporter expression in bovine cumulus-oocyte complexes and oviduct epithelial cells.

During the luteal and follicular phases of the estrous cycle, cumulus-oocyte complexes (COC) and oviduct epithelial cells (OEC) undergo notable physiological and morphological changes. Maintaining proper zinc (Zn) homeostasis is crucial in both somatic and germinal mammalian cells. This study aimed to assess the impact of the estrous phase (luteal or follicular) on Zn transporter expression in bovine COC and OEC (BOEC). The expression of Zn transporters Slc39a6 (ZIP6), Slc39a8 (ZIP8), Slc39a14 (ZIP14), Slc30a3 (ZnT3), Slc30a7 (ZnT7), and Slc30a9 (ZnT9) was analyzed in COC and BOEC from cows during the luteal or follicular phases. Gene expression of ZIP6, ZIP14, and ZnT9 was quantified in COC and BOEC. The gene expression in the remaining transporters could not be quantified due to low mRNA levels (ZIP8 and ZnT3 in COC and BOEC; ZnT7 in BOEC) or absence of expression (ZnT7 in COC). In COC, the relative expression (RE) of all three transporters was higher in the luteal phase compared to the follicular phase (P ≤ 0.05). In BOEC, the luteal phase increased the RE of ZIP 6 (P ≤ 0.05), decreased the RE of ZnT9 (P ≤ 0.05), and did not modify the RE of ZIP14 (P > 0.05) compared to the follicular phase. In conclusion, the study reveals differences in the gene expression of ZIP6, ZIP14, and ZnT9 according to the estrous cycle phase in ex vivo samples of bovine COC and OEC.

Zinc and Its Impact on the Function of the Testicle and Epididymis.

Zinc (Zn) is an essential trace element; it exhibits a plethora of physiological properties and biochemical functions. It plays a pivotal role in regulating the cell cycle, apoptosis, and DNA organization, as well as in protein, lipid, and carbohydrate metabolism. Among other important processes, Zn plays an essential role in reproductive health. The ZIP and ZnT proteins are responsible for the mobilization of Zn within the cell. Zn is an inert antioxidant through its interaction with a variety of proteins and enzymes to regulate the redox system, including metallothioneins (MTs), metalloenzymes, and gene regulatory proteins. The role of Zn in the reproductive system is of great importance; processes, such as spermatogenesis and sperm maturation that occur in the testicle and epididymis, respectively, depend on this element for their development and function. Zn modulates the synthesis of androgens, such as testosterone, for these reproductive processes, so Zn deficiency is related to alterations in sperm parameters that lead to male infertility.

MnO/ZnO:Zn Thin-Film Frequency Adaptive Heterostructure for Future Sustainable Memristive Systems.

In recent years, advances in materials engineering based on adaptive electronics have found a new paradigm to optimize drawbacks in signal processing. A two-layer MnO/ZnO:Zn heterostructure envisioned for frequency adaptive electronic signal processing is synthesized by sputtering, where the use of internal states allows reconfigurability to obtain new operating modes at different frequency input signals. X-ray diffraction (XRD) analysis is performed on each layer, revealing a cubic structure for MnO and a hexagonal structure for ZnO:Zn with preferential growth in [111] and [002] directions, respectively. Scanning electron microscope (SEM) micrographs show that the surface of both materials is homogeneous and smooth. The thickness for each layer is determined to be approximately 106.3 nm for MnO, 119.3 nm for ZnO:Zn and 224.1 nm for the MnO/ZnO:Zn structure. An electrical characterisation with an oscilloscope and signal generator was carried out to obtain the time-response signals and current-voltage (I-V) curves, where no degradation is detected when changing frequencies within the range of 100 Hz to 1 MHz. An equivalent circuit is proposed to explain the effects in the interface. Measurements of switching speeds from high resistance state (HRS) to low resistance state (LRS) at approximately 17 ns, highlight the device's rapid adaptability, and an estimated switching ratio of approximately 2 × 104 indicates its efficiency as a memristive component. Finally, the MnO/ZnO:Zn heterojunction delivers states that are stable, repeatable, and reproducible, demonstrating how the interaction of the materials can be utilised in adaptive device applications by applying frequencies and internal states to create new and innovative design schematics, thus reducing the number of components/connections in a system for future sustainable electronics.

Interaction of Zinc Mineral Nutrition and Plant Growth-Promoting Bacteria in Tropical Agricultural Systems: A Review.

The relationship between zinc mineral nutrition and plant growth-promoting bacteria (PGPB) is pivotal in enhancing agricultural productivity, especially in tropical regions characterized by diverse climatic conditions and soil variability. This review synthesizes and critically evaluates current knowledge regarding the synergistic interaction between zinc mineral nutrition and PGPB in tropical agricultural systems. Zinc is an essential and fundamental micronutrient for various physiological and biochemical processes in plants. Its deficiency affects plant growth and development, decreasing yields and nutritional quality. In tropical regions, where soil zinc availability is often limited or imbalanced, the PGPB, through different mechanisms such as Zn solubilization; siderophore production; and phytohormone synthesis, supports Zn uptake and assimilation, thereby facilitating the adverse effects of zinc deficiency in plants. This review outlines the impacts of Zn-PGPB interactions on plant growth, root architecture, and productivity in tropical agricultural systems. The positive relationship between PGPB and plants facilitates Zn uptake and improves nutrient use efficiency, overall crop performance, and agronomic biofortification. In addition, this review highlights the importance of considering indigenous PGPB strains for specific tropical agroecosystems, acknowledging their adaptability to local conditions and their potential in sustainable agricultural practices. It is concluded that Zn fertilizer and PGPBs have synergistic interactions and can offer promising avenues for sustainable agriculture, addressing nutritional deficiencies, improving crop resilience, and ensuring food security.

Ecotoxic effect in Allium cepa due to sphalerite weathering arising in calcareous conditions.

The ecotoxic effect of Zn species arising from the weathering of the marmatite-like sphalerite ((Fe, Zn)S) in Allium cepa systems was herein evaluated in calcareous soils and connected with its sulfide oxidation mechanism to determine the chemical speciation responsible of this outcome. Mineralogical analyses (X-ray diffraction patterns, Raman spectroscopy, scanning electron microscopy and atomic force microscopy), chemical study of leachates (total Fe, Zn, Cd, oxidation-reduction potential, pH, sulfates and total alkalinity) and electrochemical assessments (chronoamperometry, chronopotentiometry, cyclic voltammetry, and electrochemical impedance spectroscopy) were carried out using (Fe, Zn)S samples to elucidate interfacial mechanisms simulating calcareous soil conditions. Results indicate the formation of polysulfides (Sn2-), elemental sulfur (S0), siderite (FeCO3)-like, hematite (Fe2O3)-like with sorbed CO32- species, gunningite (ZnSO4·H2O)-like phase and smithsonite (ZnCO3)-like compounds in altered surface under calcareous conditions. However, the generation of gunningite (ZnSO4·H2O)-like phase was predominant bulk-solution system. Quantification of damage rates ranges from 75 to 90% of bulb cells under non-carbonated conditions after 15-30 days, while 50-75% of damage level is determined under neutral-alkaline carbonated conditions. Damage ratios are 70.08 and 30.26 at the highest level, respectively. These findings revealed lower ecotoxic damage due to ZnCO3-like precipitation, indicating the effect of carbonates on Zn compounds during vegetable up-taking (exposure). Other environmental suggestions of the (Fe, Zn)S weathering and ecotoxic effects under calcareous soil conditions are discussed.

Complexation of the Antihypertensive Drug Olmesartan with Zn: In Vivo Antihypertensive and Cardiac Effects.

This study is based on the premise that the application of chemical synthesis strategies to structurally modify commercial drugs by complexation with biometals is a valid procedure to improve their biological effects. Our purpose is to synthesize a compound with greater efficacy than the original drug, able to enhance its antihypertensive and cardiac pharmacological activity. Herein, the structure of the coordination compound of Zn(II) and the antihypertensive drug olmesartan, [Zn(Olme)(H2O)2] (ZnOlme), is presented. After 8 weeks of treatment in SHR male rats, ZnOlme displayed a better blood pressure-lowering activity compared with olmesartan, with a noticeable effect even in the first weeks of treatment, while ZnCl2 showed similar results than the control. ZnOlme also reduced left ventricle (LV) weight and left ventricle/tibia length ratio (LV/TL), posterior wall thickness (PWT), and intraventricular septum in diastole (IVSd) suggesting its potential to prevent LV hypertrophy. Besides, ZnOlme reduced interstitial fibrosis (contents of collagen types I and III, responsible for giving rigidity and promoting vascular elasticity, respectively). The recovery of heart function was also evidenced by fractional shortening (diastolic left ventricular/systolic left ventricular) diameter determinations. Furthermore, ZnOlme increased the antioxidant capacity and prevented cardiac oxidative stress: it enhanced the reduction of reactive oxygen species generation, exerted a significant decrease in lipid peroxidation and enhanced glutathione contents in heart tissues compared to the control, Zn, and olmesartan treatments. Our results demonstrate that continuous oral administration of ZnOlme causes a better antihypertensive effect and grants enhancement of cardioprotection through antioxidant activity, in combination with hemodynamic improvement.

Pesticides luminescent sensing by a Tb3+-doped Zn metal-organic framework with selectivity towards parathion.

Organophosphorus pesticides (OPPs) such as parathion have extensive uses in agriculture and household applications. Chronic exposure to these pesticides can cause severe health and environmental issues. Therefore, a current ecological concern is associated with accumulating these noxious OPPs in food and water sources. In this work, a new Tb3+-doped Zn-LMOF (Zn-LMOF= (3D) {[Zn3(1,4 benzenedicarboxylate)3(EtOH)2]·(EtOH)0.6}∞) was synthesized by a solvent-free reaction between the Zn-LMOF and the salt TbCl3·6H2O using a high-speed ball milling. The Tb@Zn-LMOF was thoroughly characterized by multiple spectroscopic tools, including Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy, and studied in-depth as a luminescent sensor for a series of pesticides (parathion, malathion, methalaxil, carbofuran, iprodione, captan and glyphosate) in aqueous methanol. The Tb@Zn-LMOF is a long-lived green-emitting compound with luminescence originated by an efficient antenna effect from the excited energy levels of Zn-LMOF toward the 5D state of Tb3+ ions, as it is displayed by its strong emission bands at 488, 545, 585, and 620 nm and a lifetime of 1.01 ms upon excitation at 290 nm. Additions of pesticides to a neutral methanolic dispersion of Tb@Zn-LMOF modified its green emission intensity with a pronounced selectivity toward parathion within the micromolar concentration range. The detection limit for parathion was calculated to be 3.04 ± 0.2 µM for Tb@Zn-LMOF. Based on 31P NMR and mass spectrometry studies, it is attributed to the release of lanthanide ions from Tb@Zn-LMOF with the simultaneous formation of a Tb3+-parathion complex.

Improvement of the cardiovascular effect of methyldopa by complexation with Zn(II): Synthesis, characterization and mechanism of action.

BACKGROUND: the antihypertensive drug α-methyldopa (MD) stands as one of the extensively used medications for managing hypertension during pregnancy. Zinc deprivation has been associated with many diseases. In this context, the synthesis of a Zn coordination complex [Zn(MD)(OH)(H2O)2]·H2O (ZnMD) provide a promising alternative pathway to improve the biological properties of MD. METHODS: ZnMD was synthesized and physicochemically characterized. Fluorescence spectral studies were conducted to examine the binding of both, the ligand and the metal with bovine serum albumin (BSA). MD, ZnMD, and ZnCl2 were administered to spontaneous hypertensive rats (SHR) rats during 8 weeks and blood pressure and echocardiographic parameters were determined. Ex vivo assays were conducted to evaluate levels of reactive oxygen species (ROS), thiobarbituric acid reactive substances (TBARS), and nitric oxide (NO). Cross-sectional area (CSA) and collagen levels of left ventricular cardiomyocytes were also assessed. Furthermore, the expression of NAD(P)H oxidase subunits (gp91phox and p47phox) and Superoxide Dismutase 1 (SOD1) was quantified through western blot analysis. RESULTS: The complex exhibited a moderate affinity for binding with BSA showing a spontaneous interaction (indicated by negative ΔG values) and moderate affinity (determined by affinity constant values). The binding process involved the formation of Van der Waals forces and hydrogen bonds. Upon treatment with MD and ZnMD, a reduction in the systolic blood pressure in SHR was observed, being ZnMD more effective than MD (122 ± 8.1 mmHg and 145 ± 5.6 mmHg, at 8th week of treatment, respectively). The ZnMD treatment prevented myocardial hypertrophy, improved the heart function and reduced the cardiac fibrosis, as evidenced by parameters such as left ventricular mass, fractional shortening, and histological studies. In contrast, MD did not show noticeable differences in these parameters. ZnMD regulates negatively the oxidative damage by reducing levels of ROS and lipid peroxidation, as well as the cardiac NAD(P)H oxidase, and increasing SOD1 expression, while MD did not show significant effect. Moreover, cardiac nitric oxide levels were greater in the ZnMD therapy compared to MD treatment. CONCLUSION: Both MD and ZnMD have the potential to be transported by albumin. Our findings provide important evidence suggesting that this complex could be a potential therapeutic drug for the treatment of hypertension and cardiac hypertrophy and dysfunction.

Zn-doped MnOx nanowires displaying plentiful crystalline defects and tunable small cross-sections for an optimized volcano-type performance towards supercapacitors.

MnOx-based nanomaterials are promising large-scale electrochemical energy storage devices due to their high specific capacity, low toxicity, and low cost. However, their slow diffusion kinetics is still challenging, restricting practical applications. Here, a one-pot and straightforward method was reported to produce Zn-doped MnOx nanowires with abundant defects and tunable small cross-sections, exhibiting an outstanding specific capacitance. More specifically, based on a facile hydrothermal strategy, zinc sites could be uniformly dispersed in the α-MnOx nanowires structure as a function of composition (0.3, 2.1, 4.3, and 7.6 wt.% Zn). Such a process avoided the formation of different crystalline phases during the synthesis. The reproducible method afforded uniform nanowires, in which the size of cross-sections decreased with the increase of Zn composition. Surprisingly, we found a volcano-type relationship between the storage performance and the Zn loading. In this case, we demonstrated that the highest performance material could be achieved by incorporating 2.1 wt.% Zn, exhibiting a remarkable specific capacitance of 1082.2 F.g-1 at a charge/discharge current density of 1.0 A g-1 in a 2.0 mol L-1 KOH electrolyte. The optimized material also afforded improved results for hybrid supercapacitors. Thus, the results presented herein shed new insights into preparing defective and controlled nanomaterials by a simple one-step method for energy storage applications.

CRISPR/Cas9-Mediated Disruption of the pcz1 Gene and Its Impact on Growth, Development, and Penicillin Production in Penicillium rubens.

Penicillium rubens is a filamentous fungus of great biotechnological importance due to its role as an industrial producer of the antibiotic penicillin. However, despite its significance, our understanding of the regulatory mechanisms governing biological processes in this fungus is still limited. In fungi, zinc finger proteins containing a Zn(II)2Cys6 domain are particularly interesting regulators. Although the P. rubens genome harbors many genes encoding proteins with this domain, only two of them have been investigated thus far. In this study, we employed CRISPR-Cas9 technology to disrupt the pcz1 gene, which encodes a Zn(II)2Cys6 protein in P. rubens. The disruption of pcz1 resulted in a decrease in the production of penicillin in P. rubens. This decrease in penicillin production was accompanied by the downregulation of the expression of pcbAB, pcbC and penDE genes, which form the biosynthetic gene cluster responsible for penicillin production. Moreover, the disruption of pcz1 also impacts on asexual development, leading to decreased growth and conidiation, as well as enhanced conidial germination. Collectively, our results indicate that pcz1 acts as a positive regulator of penicillin production, growth, and conidiation, while functioning as a negative regulator of conidial germination in P. rubens. To the best of our knowledge, this is the first report involving a gene encoding a Zn(II)2Cys6 protein in the regulation of penicillin biosynthesis in P. rubens.

Strengthening collaborations at the Biology-Physics interface: trends in antimicrobial photodynamic therapy.

The unbridled use of antimicrobial drugs over the last decades contributed to the global dissemination of drug-resistant pathogens and increasing rates of life-threatening infections for which limited therapeutic options are available. Currently, the search for safe, fast, and effective therapeutic strategies to combat infectious diseases is a worldwide demand. Antimicrobial photodynamic therapy (APDT) rises as a promising therapeutic approach against a wide range of pathogenic microorganisms. APDT combines light, a photosensitizing drug (PS), and oxygen to kill microorganisms by oxidative stress. Since the APDT field involves branches of biology and physics, the strengthening of interdisciplinary collaborations under the aegis of biophysics is welcome. Given this scenario, Brazil is one of the global leaders in the production of APDT science. In this review, we provide detailed reports of APDT studies published by the Laboratory of Optical Therapy (IPEN-CNEN), Group of Biomedical Nanotechnology (UFPE), and collaborators over the last 10 years. We present an integrated perspective of APDT from basic research to clinical practice and highlight its promising use, encouraging its adoption as an effective and safe technology to tackle important pathogens. We cover the use of methylene blue (MB) or Zn(II) porphyrins as PSs to kill bacteria, fungi, parasites, and pathogenic algae in laboratory assays. We describe the impact of MB-APDT in Dentistry and Veterinary Medicine to treat different infectious diseases. We also point out future directions combining APDT and nanotechnology. We hope this review motivates further APDT studies providing intuitive, vivid, and insightful information for the readers.

Zn-Salphen Acrylic Films Powered by Aggregation-Induced Enhanced Emission for Sensing Applications.

Zn(II) complexes possess attractive characteristics for supramolecular chemistry, catalysis, and optoelectronic applications, while Zn-Salphen counterparts are also suitable as chemical sensors, although limited by solution-based to date. In this study, we report the synthesis of new polymers from methyl methacrylate, n-butyl acrylate, and a non-symmetrical Zn-Salphen complex. We show that this low-fluorescent complex exhibits aggregation-induced emission enhancement (AIEE) properties and that, the incorporation of AIEE complexes into a polymeric matrix make it possible to achieve fluorescent films with enhanced fluorescence suitable for sensing applications. As a proof of concept, these films could detect acetic acid, showing a decrease of up to 73% in the original fluorescence. Host/guest studies showed a subtle disruption of the emission in aggregates upon treatment with anion guests. These results indicate that an interaction between the guest and Zn-Salphen complex may occur, stabilizing or destabilizing the complex and causing a concomitant increase or decrease in emission.

Sustainable Cellulose Nanofibers-Mediated Synthesis of Uniform Spinel Zn-Ferrites Nanocorals for High Performances in Supercapacitors.

Spinel ferrites are versatile, low-cost, and abundant metal oxides with remarkable electronic and magnetic properties, which find several applications. Among them, they have been considered part of the next generation of electrochemical energy storage materials due to their variable oxidation states, low environmental toxicity, and possible synthesis through simple green chemical processing. However, most traditional procedures lead to the formation of poorly controlled materials (in terms of size, shape, composition, and/or crystalline structure). Thus, we report herein a cellulose nanofibers-mediated green procedure to prepare controlled highly porous nanocorals comprised of spinel Zn-ferrites. Then, they presented remarkable applications as electrodes in supercapacitors, which were thoroughly and critically discussed. The spinel Zn-ferrites nanocorals supercapacitor showed a much higher maximum specific capacitance (2031.81 F g-1 at a current density of 1 A g-1) than Fe2O3 and ZnO counterparts prepared by a similar approach (189.74 and 24.39 F g-1 at a current density of 1 A g-1). Its cyclic stability was also scrutinized via galvanostatic charging/discharging and electrochemical impedance spectroscopy, indicating excellent long-term stability. In addition, we manufactured an asymmetric supercapacitor device, which offered a high energy density value of 18.1 Wh kg-1 at a power density of 2609.2 W kg-1 (at 1 A g-1 in 2.0 mol L-1 KOH electrolyte). Based on our findings, we believe that higher performances observed for spinel Zn-ferrites nanocorals could be explained by their unique crystal structure and electronic configuration based on crystal field stabilization energy, which provides an electrostatic repulsion between the d electrons and the p orbitals of the surrounding oxygen anions, creating a level of energy that determines their final supercapacitance then evidenced, which is a very interesting property that could be explored for the production of clean energy storage devices.

Theoretical studies of Zn2+ complexes with alkyl xanthate ligands: a thermochemical, electronic energy decomposition, and natural bond orbital analysis.

CONTEXT: Xanthates are organic compounds that present great interest for coordination chemistry, because they can bond in different ways to the metal ion. Thus, these compounds have several applications, being best known for their environmental application. In fact, xanthates are recognized for their application as heavy metal collector agents in aqueous environments. In view of this application, this study is aimed at showing the thermochemical and electronic parameters obtained for the reactions of substitution water molecules in the aqua zinc complexes, by xanthate ligands (n-propyl, n-butyl, and n-pentyl xanthates). In addition to their environmental application, xanthates have shown biological properties, such as anti-bacterial and anti-cancer. In recent years, xanthates have also been used in the technological area, where it participates as a precursor of sulfides for the manufacture of thin films. Our results showed complexes with distorted octahedral geometries and with negative values of enthalpy and Gibbs free energy, indicating exothermic and spontaneous processes. For all the complexes, it was observed that Zn2+ complexes have both an ionic and covalent character. However, the monosubstituted complexes showed a predominance of the ionic character. In addition, high donor-acceptor interaction energies were obtained, indicating a good superposition between the s and p orbitals involved in the Zn-S bond. METHODS: This work consists in theoretical studies of Zn2+ complexes with alkyl xanthate ligands, with different structures, where optimization and normal modes calculations were performed at different DFT levels: M06L, M06-2X, wB97XD, and B3LYP/6-311++G**+LANL2TZ, with Gaussian09 program. The process of substitution of two aqua by two xanthate ligands was analyzed in stages, forming cationic and neutral complexes, in the first and second stages, respectively. In addition, electronic energy decomposition (EDA) and natural bond orbital (NBO) analysis were performed at level M06L/6-311++G**+LANL2TZ with Gamess program.

Importance of Magnesium Status in COVID-19.

A large amount of published research points to the interesting concept (hypothesis) that magnesium (Mg) status may have relevance for the outcome of COVID-19 and that Mg could be protective during the COVID disease course. As an essential element, Mg plays basic biochemical, cellular, and physiological roles required for cardiovascular, immunological, respiratory, and neurological functions. Both low serum and dietary Mg have been associated with the severity of COVID-19 outcomes, including mortality; both are also associated with COVID-19 risk factors such as older age, obesity, type 2 diabetes, kidney disease, cardiovascular disease, hypertension, and asthma. In addition, populations with high rates of COVID-19 mortality and hospitalization tend to consume diets high in modern processed foods, which are generally low in Mg. In this review, we review the research to describe and consider the possible impact of Mg and Mg status on COVID-19 showing that (1) serum Mg between 2.19 and 2.26 mg/dL and dietary Mg intakes > 329 mg/day could be protective during the disease course and (2) inhaled Mg may improve oxygenation of hypoxic COVID-19 patients. In spite of such promise, oral Mg for COVID-19 has thus far been studied only in combination with other nutrients. Mg deficiency is involved in the occurrence and aggravation of neuropsychiatric complications of COVID-19, including memory loss, cognition, loss of taste and smell, ataxia, confusion, dizziness, and headache. Potential of zinc and/or Mg as useful for increasing drug therapy effectiveness or reducing adverse effect of anti-COVID-19 drugs is reviewed. Oral Mg trials of patients with COVID-19 are warranted.

Novel Zn(II)-complex with hybrid chalcone-thiosemicarbazone ligand: Synthesis, characterization, and inhibitory effect on HTLV-1-infected MT-2 leukemia cells.

Chalcone and thiosemicarbazone have attracted attention due to their easy synthetic procedure and high success in the development of antiviral and antitumor, however, there are few biological data on the evaluation of chalcone-thiosemicarbazone hybrids and their complexation with metal ions. In this sense, the present work reports the synthesis and characterization of the hybrid (Z)-2-((E)-3-(4-chlorophenyl)-1-phenylallylidene)hydrazine-1-carbothioamide (CTCl) and its Zn(II)-complex (CTCl-Zn). The compounds were cell-based evaluated in terms of cytotoxicity against human T-cell lymphotropic virus type 1 (HTLV-1) infected leukemia cells (MT-2) and the experimental data were correlated with molecular docking calculations. The ligand and Zn(II)-complex were easily synthesized with a good yield - 57% and 79%, respectively. The dynamic of E/Z isomers with respect to the imine bond configuration of CTCl was evidenced by 1H NMR experiments in DMSO­d6, while the X-ray diffraction of CTCl-Zn showed that Zn(II) ion is tetracoordinated to two ligands in a bidentate mode and the metal ion lies on an intermediate geometry between the see-saw and trigonal pyramid. The ligand and complex exhibited low toxicity and the Zn(II)-complex is more cytotoxic than the ligand, with the corresponding IC50 value of 30.01 and 47.06 µM. Both compounds had a pro-apoptotic effect without the release of reactive oxygen species (ROS) and they can interact with DNA via minor grooves driven by van der Waals forces.

Effect of the structural modification of Candesartan with Zinc on hypertension and left ventricular hypertrophy.

Hypertension is the most common cause of left ventricular hypertrophy, contributing to heart failure progression. Candesartan (Cand) is an angiotensin receptor antagonist widely used for hypertension treatment. Structural modifications were previously performed by our group using Zinc (ZnCand) as a strategy for improving its pharmacological properties. The measurements showed that ZnCand exerts a stronger interaction with the angiotensin II receptor, type 1 (AT1 receptor), reducing oxidative stress and intracellular calcium flux, a mechanism implied in cell contraction. These results were accompanied by the reduction of the contractile capacity of mesangial cells. In vivo experiments showed that the complex causes a significant decrease in systolic blood pressure after 8 weeks of treatment in spontaneously hypertensive rats (SHR). The reduction of heart hypertrophy was evidenced by echocardiography, the histologic cross-sectional area of cardiomyocytes, collagen content, the B-type natriuretic peptide (BNP) marker and connective tissue growth factor (CTGF) and the matrix metalloproteinase 2 (MMP-2) expression. Besides, the complex restored the redox status. In this study, we demonstrated that the complexation with Zn(II) improves the antihypertensive and cardiac effects of the parental drug.

Modulation of Zinc Transporter Expressions by Additional Zinc in C2C12 Cells Cultured in a High Glucose Environment and in the Presence of Insulin or Interleukin-6.

Zn status has been related to various chronic diseases presenting oxidative stress and inflammation, such as type 2 diabetes. Zn supplementation has been suggested to be a potential coadjuvant in the management of this condition. Zn transporters constitute a key component in the maintenance of Zn homeostasis. Our aim was to evaluate the modulatory effect of additional Zn (10 or 100 µM; as a ZnSO4*7H20) on the mRNA relative expression of selected Zn transporters (ZnT1, ZnT5, ZnT7, ZIP6, ZIP7, ZIP10, ZIP14), in myoblast (C2C12) cells cultured in normal (10 mM) and high glucose (30 mM), and in the absence or presence of insulin (1 nM), and interleukin-6 (IL-6; 5 nM) for 24 h. The main findings of our study were that in high glucose conditions in absence of insulin or IL-6, additional Zn increased ZnT1 and ZIP6, and decreased ZnT5 and ZIP7 expressions. However, this situation is modified by insulin, where incremental Zn induced increased expressions of ZnT1, ZnT5, and all the ZIP transporters studied. In high glucose conditions and in the presence of IL-6, additional Zn caused increased expressions of ZnT7, ZIP7, and ZIP14, compared with results in the absence of IL-6. This study provides preliminary evidence for the differential expression of selected Zn transporters in C2C12 cells subjected to high glucose and incremental Zn, suggesting that important changes in intracellular Zn distribution take place in response to inflammatory and high-insulin environments. Further study is necessary to understand the implications of these findings.