Zn Profiles Research Articles

A multifaceted analysis: Unveiling the complexities of wheat genotypes, fortification, and processing on iron and zinc bioavailability in whole wheat flour and chapati.

This study examines the complex interactions between wheat cultivar selection and fortification with NaFeEDTA and ascorbic acid (AA) on the bioavailability of iron (Fe) and zinc (Zn) in whole wheat flour (WWF) and chapati. Nineteen hexaploid wheat cultivars were rigorously assessed for their intrinsic Fe and Zn profiles, including total content (TC), solubility (S), and bio-accessibility (B), utilizing an in-vitro gastrointestinal model. Significant variations (P<0.05) were observed among cultivars, with Fe content ranging from 32.8mg.kg-1 to 42.8mg.kg-1 and Zn content ranging from 34.5mg.kg-1 to 43.8mg.kg-1 in WWF. Fortification with NaFeEDTA (T3: 250mg.kg-1) significantly increased total Fe TC in WWF by 85.0%, Fe and Zn solubility by 51.2% and 22.3%, and bio-accessibility by 165.5% and 84.2%, respectively, compared to control. Conversely, AA fortification (T3: 250mg.kg-1) elevated Fe and Zn solubility by 98.7% and 62.1%, and bio-accessibility by 282.2% and 230.5%, respectively, compared to control. Notably, cultivar-specific responses to both fortification strategies were also evident. When translated to chapati, both NaFeEDTA and AA fortification (T3) enhanced Fe and Zn bio-accessibility compared to unfortified chapati. The impact of fortification was cultivar-dependent, with certain cultivars showing greater efficacy in improving Fe and Zn bio-accessibility. Correlation analysis revealed intricate relationships among Fe and Zn bioavailability parameters, highlighting the importance of tailored fortification approaches. These findings have significant implications for optimizing fortification strategies to improve bioavailable Fe and Zn intake through wheat-based diets.

Effect of Li on the Uniformity of Zn Recharge Reaction in the Anodic ZnO Passivation Layer

Alkaline rechargeable Zn batteries are regarded as next-generation energy storage systems owing to their cost-effectiveness, safety, and high theoretical capacity. Nevertheless, their application is limited because of the degradation of Zn anodes during charge-discharge cycles. The most notable example of the degradation phenomena is dendrite formation during charge. Under conditions with high current density, current is concentrated at the protruding points of the electrode surface due to significant growth of the diffusion layer. This induces dendritic structures to grow perpendicular to the substrate, which causes short circuits in the worst case. Several methods, such as adding additives to the electrolyte and modifying the surface of electrodes via alloying or coating, have been proposed to suppress dendrites. In particular, additives have been widely investigated to achieve a cost-effective and simple battery manufacturing process. Their effects are often explained in terms of adsorption behavior on pristine Zn surfaces. In practical cases, however, surface states of Zn are more complicated due to the ZnO formation during discharge. Previous studies have suggested that the passivation layer on metal anodes (e.g. Al and Li) has a significant influence on dendritic growth behavior.[1, 2] Therefore, in this study, we investigate the additive effect on the dendritic growth of Zn in the presence of the ZnO passivation layer formed after discharge. In particular, we focus on the additive effect of Li+. Li+ induces crystalline defects in ZnO by inhibiting the crystallization process.[3] Since the electrical properties of ZnO are greatly affected by crystalline defects, Li+ is a qualified additive to focus on in this study, which investigates the influence of the ZnO passivation layer. In addition, Li+ is an interesting target to investigate its additive effects during recharge since it has been identified by our group as an effective additive to inhibit undesirable property changes such as mossy growth and passivation.[3, 4] Fig. 1 shows the surface morphology of the Zn recharged in the presence of varying concentrations of Li+. Without Li+, the Zn electrodeposits contain leaf-like dendrites. In contrast, 0.1 M Li+ addition leads to finer morphology with fewer dendrites. Conversely, with 2 M Li+ addition, the rough deposits containing more and larger dendrites are observed. Notably, the Zn deposition morphology at the initial charge was independent of the concentration of Li+. Therefore, Zn deposition morphology during recharge was most likely affected by the property difference of the ZnO passivation layer formed during discharge. Moreover, the potential profile of Zn during recharge suggested that the conductivity of the ZnO passivation layer was dependent on the concentration of Li+: it increased with 0.1 M Li+ addition and decreased with 2 M Li+ addition. The conductivity changes were attributed to the carrier density change due to crystalline defect formation. These results suggest that the ZnO passivation layer with high conductivity is ideal for suppressing the dendritic growth of Zn during recharge. Furthermore, controlling crystalline defects with additives is an effective strategy for forming a conductive ZnO passivation layer.

Decentralized touch-based micronutrition sensor towards personalized nutrition: Parallel detection of sweat ascorbic acid and zinc ions

The zinc (Zn) and ascorbic acid (AA) micronutrient duo has received a considerable attention in individual’s nutrition plans, particularly after the recent pandemic, owing to its distinct beneficial impact on boosting the immune system. Accordingly, there are growing needs for frequent and decentralized measurements of the trace element and micronutrient levels towards well-balanced personalized nutrition. Leveraging natural sweat sampling from the fingertip, we describe here a disposable electrochemical sensor array, consisting of neighboring Zn ion (Zn(II)), and AA electrodes, towards parallel touch-based on-site monitoring of dynamically-changing sweat Zn(II), and AA levels, following the intake of the corresponding nutrition supplements.. A highly permeable poly (vinyl alcohol) (PVA) hydrogel, placed on the dual-electrode sensor array, served for transferring the sweat from the fingertip onto the electrode surface. Zn(II) measurements were performed on a bismuth/Nafion modified screen printed electrode (SPE) with square-wave anodic stripping voltammetry (SWASV), while the AA detection relied on recording of the open circuit potential (OCP) change, on the tetrathiafulvalene-7,7,8,8-tetracyanoquinodimethane (TTF-TCNQ) immobilized SPE. Rapid decentralized measurements of sweat Zn(II) and AA temporal profiles were carried out on the fingertip sweat of healthy subjects after consuming pill supplements in connection to the disposable strip along with hand-held electrochemical analyzer. The utility of the touch-based disposable Zn(II)/AA multisensory platform for parallel measurements of this pair of micronutrients was demonstrated towards personalized nutrition by providing real-time monitoring of the dose-response relationship. Our findings indicate that the new sweat nutrition sensing device holds considerable promise for guiding dietary interventions and enhancing personalized nutrition.

Effects of zinc supplementation from organic and inorganic sources on growth, blood biochemical indices, and intestinal microarchitecture in broilers

In poultry nutrition, zinc supplementation is typically achieved through the addition of zinc oxide or zinc sulfate to the feed. The alternative approach of organic sources utilizes an organic ligand to bind zinc (Zn), resulting in higher bioavailability. Thus, a study was conducted to assess and compare the impact of a methionine-complexed Zn versus an inorganic Zn on growth, blood biochemical profile, gut histomorphology, and fecal excretion of Zn in broilers. The experimental design included two treatments: the addition of a zinc amino acid complex or zinc oxide to the basal diet. The zinc amino acid complex was supplemented at a dose equivalent to the inorganic zinc (Zn-80), while the organic zinc was provided at levels of 20, 40, and 80 mg/kg to a total of 400 broilers. There were five treatments in total, and each treatment was replicated four times. Broilers supplemented with an organic form of Zn at the level of 80 mg/kg had significantly (p < 0.05) higher body weight gain and lower feed conversion ratio (F/G). Significantly (p < 0.05) higher Zn excretion was recorded in broilers supplemented with inorganic Zn supplementation. Significantly (p < 0.05) higher villus length and width, their ratio, and lower (p < 0.05) crypt depth were observed in birds supplemented with 80 mg/kg organic Zn. From the results of the present study, it was concluded that Zn from an organic source at the rate of 80 mg/kg was superior in terms of growth performance, intestinal histomorphology and less excretion of Zn to the environment in broilers.

Associations of urinary zinc exposure with blood lipid profiles and dyslipidemia: Mediating effect of serum uric acid

The relationship between zinc (Zn) exposure and abnormal blood lipids including dyslipidemia is contentious. Serum uric acid (SUA) has been reported to be correlated to both Zn exposure and dyslipidemia. The underlying mechanisms of Zn exposure associated with blood lipids and the mediating effects of SUA remain unclear. Therefore, this study analyzed the data from Chinese 2110 adults (mean age: 59.0 years old) in rural areas across China to explore the associations of Zn exposure with blood lipid profiles and dyslipidemia, and to further estimate the mediating effects of SUA in these relationships. The study data showed that urinary Zn was associated with increased levels of blood lipid components triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C). Moreover, an increased risk of dyslipidemia was observed in the study participants who had higher urinary Zn levels. Compared with the first quartile, the fourth quartile of urinary Zn concentration corresponded to the increase of TG (β = 0.20, 95 % CI: 0.12, 0.28), LDL-C (β = 0.06, 95 % CI: 0.01, 0.10) and dyslipidemia risk (OR = 2.16, 95 % CI: 1.50, 3.10), respectively. Elevated urinary Zn was also associated with higher levels of SUA and hyperuricemia risk. The SUA levels were positively related to total cholesterol (TC), TG, LDL-C levels and dyslipidemia risk. Mediation analyses revealed that SUA mediated 31.75 %, 46.16 % and 19.25 % of the associations of urinary Zn with TG, LDL-C levels and dyslipidemia risk, respectively. The subgroup and sensitivity analyses confirmed the positive associations between urinary Zn and blood lipid profiles and the mediating effect of SUA. The national population-based study further enhanced our understanding of the associations between Zn exposure and blood lipid profiles and mediating effect of SUA among generally healthy, middle-aged, and elderly individuals.

Historical trend of heavy metals in mangrove sediment from Nusa Lembongan, Bali using 210Pb-geochronology

Mangrove sediment is a natural filter for retaining pollutants before entering the coastal area and ocean. This study collected sediment cores from a Marine Protected Area (MPA) in Nusa Lembongan, Bali, to establish 210Pb geochronology and heavy metals records. Alpha spectrometry and Instrumental Neutron Activation Analysis (INAA) were used to determine 210Pb and heavy metals (Co, Cr, Fe, Hf, Sb, Sc, Se, and Zn), respectively. The Contamination Factor (CF), Enrichment Factor (EF), and Geo-accumulation Index (I_geo) were assessed. The result shows that 210Pb provided records of sediment accumulation spanning approximately 100 years. The vertical profiles of all heavy metals from the 1910s to the 1930s were slightly constant. From the 1930s to the 1990s, the profiles of Co, Cr, Hf, Sb, Sc, and Zn slightly increased; meanwhile, Fe and Se were slightly constant. From the 1990s to 2017, all heavy metals decreased gradually. Based on the CF, heavy metals Cr, Hf, Sb, Sc, and Zn were categorized as moderate contamination, and Co, Fe, and Se were low contamination. The average EFs of all heavy metals suggested their origin was derived from crustal material. In the I_geo index, only Sb was classified as moderate pollution, while the other heavy metals were not pollutants.

Dietary green-synthesized curcumin-mediated zinc oxide nanoparticles promote growth performance, haemato-biochemical profile, antioxidant status, immunity, and carcass quality in Nile tilapia (Oreochromis niloticus)

This study evaluated the effect of dietary curcumin-assisted green synthesized zinc oxide nanoparticles (CUR-ZnONPs) on growth performance, haemato-biochemical profile, antioxidant capacity, immune response, carcass composition, and bioaccumulation of Zn in Nile tilapia. The fish (‎16.20 ± 1.02 g‎) were fed with diets enriched with 0 (CZP1), 5 (CZP2), 7.5 (CZP3), and 10 (CZP4) mg/kg CUR-ZnONPs for 56 days and then challenged with Aeromonas hydrophila. The highest growth performance (final weight, weight gain, and specific growth rate) and the lowest feed conversion ratio were recorded in CZP4 (P < 0.05). Feeding the fish with CZP4 resulted in a significant increase in the hematological indices, body crude protein content, ‎antioxidant capacity (superoxide dismutase and reduced glutathione), and humoral immunity (immunoglobulin M, lysozyme, and complement pathway activity) (P < 0.05). However, the levels of malondialdehyde, body crude lipid, cholesterol, and aspartate aminotransferase were significantly decreased in the fish fed with CZP4 compared to others (P < 0.05). There was no significant difference in the values of glucose, alanine aminotransferase, catalase, monocyte count, and muscle Zn accumulation between the treated fish and the control group (P > 0.05). The mortality rate of the fish infected with A. hydrophila was significantly lower in the group that received CZP4 compared to the other experimental groups (P < 0.05). The principal component analysis demonstrated that the fish fed with CUR-ZnONPs have significantly higher growth performance, immune responses, and antioxidant status than the fish fed with the control diet. Overall, it is suggested to use dietary CUR-ZnONPs, especially at 10 mg/kg, as a beneficial feed supplement to improve growth performance, antioxidant status, and immune parameters in Nile tilapia.

Investigation of interdiffusion in thin films of ZnO/ZnCdO grown by molecular beam epitaxy

Rutherford backscattering spectrometry (RBS) was used to determine the composition, uniformity, impurity, and elemental depth profiles of Zn, Cd, and O in ZnCdO/ZnO thin film deposited on differently oriented Al2O3 substrates using molecular beam epitaxy technique. For the films deposited under the same condition, it was observed that the variation of Zn/Cd/O ratios is dependent on substrate orientation and highly depends on the growth parameters. The composition and thickness variation, in relationship with two different substrates orientations, were explored with RBS, scanning electron microscopy, and photoluminescence measurements. It was found that ZnCdO films deposited on r- oriented ZnO buffers exhibit much less surface roughness and intermixing after the rapid thermal processing annealing is less extensive.

Integrated evaluation of the requirements and excretions of Cu, Fe, Zn, and Mn for broilers via a uniform design method.

This study aimed to determine the ideal balance profile of Cu, Fe, Zn, and Mn for broilers of 1-21 days of age via a uniform experimental design. In Experiment 1, 900 1-day-old Arbor Acres male broilers were randomly allotted to 15 dietary treatments with six replicates of 10 birds. A total of 14 experimental diets were formulated with the supplementation of 8~16, 123~160, 40~80, and 60~120 mg/kg of Cu, Fe, Zn, and Mn, respectively, in the basal diet, according to the uniform design method. The excretion of Cu, Fe, Zn, and Mn in the manure and the broiler performance were determined to build the ideal balance profile of these elements. Experiment 2 was conducted based on the ideal balance profile built in Experiment 1, to test its practicability using 720 broilers with two treatments. The dietary concentrations of Cu, Fe, Zn, and Mn in the control group were 15.19, 203.08, 76.78, and 86.13 mg/kg, respectively. In Experiment 1, the concentrations of Cu, Fe, Zn, and Mn in the diets were 16.96, 166.66, 46.01, and 60.26 mg/kg, respectively, when the average daily gain reached the optimum value. When the dietary concentrations of Cu, Fe, Zn, and Mn were 8.54, 130.66, 38.19, and 64.07 mg/kg, respectively, the total excretion of Cu, Fe, Zn, and Mn got the minimum value. There are corresponding ideal balance profiles for minimum excretion of a certain element. In Experiment 2, the dietary levels of Fe, Zn, and Mn were decreased by 17.93%, 40.08%, and 30.04%, respectively, which had no significant effect on average daily gain, average daily feed intake, and feed gain for 1~21 day-old broilers but markedly decreased the excretion of Cu and Mn and total excretion. It was concluded that there is a dilemma between growth performance and mineral excretion. Although dietary levels of Cu, Fe, Zn, and Mn supporting optimal growth are higher than those for minimizing mineral excretion, supplementing too many trace elements in the diets of broilers is unnecessary.

Hybrid Aqueous Alkaline Zinc/TEMPO Flow Battery: A Sustainable High Voltage Green Energy Storage Device

Aqueous organic redox flow batteries (AORFBs) have number of distinct benefits for large scale energy storage, including synthetically configurable high oxidation/reduction redox potentials and excellent solubility. AORFBs still have poor energy density due to the low cell voltage, which is limited by either catholyte or anolyte. The hybrid RFB inherits the benefits of both aqueous and non-aqueous systems, demonstrating promising characteristics for next generation RFBs such as high potential window and maximum energy density. The hybrid neutral Zinc/TEMPO polymer hybrid flow battery exhibits the limiting cell voltage of 1.4 V, which resulting the low energy density. Herein, we freshly coupled alkaline Zn(OH)4 2−/4-Hydroxy 2,2,6,6-Tetramethylpiperidine 1-oxyl (4HT) as a hybrid RFB system which exhibits the high cell voltage of 2.1 V with 25.32 Wh l−1 energy density. The galvanostatic charge-discharge shows stable performance at 5 to 40 mA cm−2 with the maximum 90% coulombic efficiency. The high rate GCD profile of alkaline Zn(OH)4 2-/4HT at 40 mA cm−2 current density have shown 90% coulombic efficiency and 60% energy efficiency. More importantly, the alkaline-based Zn(OH)4 2−/4HT exhibits remarkable capacity retention of 99.99% over 100 cycles with 25.32 Wh l−1 energy density. Thus, the freshly developed alkaline Zn(OH)4 2−/4HT system would be a potential high voltage RFB for bulk energy storage.

Elemental study of Devarda’s alloy using calibration free-laser induced breakdown spectroscopy (CF‒LIBS)

In the present study, we present the compositional analysis of a Devarda’s alloy using the calibration–free laser-induced breakdown spectroscopy (CF-LIBS) technique. A nanosecond pulsed Q-switched Nd:YAG laser was focused on the target-sample under investigation to ablate its surface and the measured emission spectrum was registered by using a spectrometer (LIBS2000+) having the optical spectral within a range from 200–720 nm. The analysis of the measured optical spectra confirms the presence of three major elements Aluminum (Al), Copper (Cu), and Zinc (Zn) in the target sample. The emission intensity line profiles of Zn, Cu, and Al were utilized to estimate the plasma-parameters consisting of excitation temperature, and the plasma number density. The plasma excitation temperature was investigated using the Boltzmann-plot technique, which yields the temperature for Cu and Zn as 8547 ± 5% K and 8100 ± 5%, respectively, while the electron plasma density was calculated from the Stark-broadening of individual neutral emission lines of Al, Cu, and Zn. For the quantitative analysis of the elements that exist in the target sample, a CF-LIBS technique was employed by assuming the condition of optically thin plasma as well as local thermodynamics equilibrium. Using the CF-LIBS technique, the relative composition in the form of weight percentage was estimated to be Zn: 57%, Al: 39%, and Cu: 4%, whereas, the certified concentration of Devarda’s alloy was 50% for Zn, 45% for Al, and 5% for Cu. These measured results reveal that the elemental concentration utilizing CF-LIBS shows a reasonable agreement with standard estimates illustrated by the manufacturer. This study further suggests that the CF-LIBS technique opens up an opportunity for engineering and industrial usage of LIBS where a quantifiable study of the substance is exceedingly advantageous.

Phytotoxicity level and accumulation ability of pot marigold (Calendula officinalis L.) to zinc

The study aims to reveal the effects of different Zn levels on pot marigold. We determined some germination and young seedling properties in the first experiment, and morphological, stomatal, and physiological parameters besides uptake profiles of both Zn and other plant nutrients in the second one. We supplied the water requirement of the seeds with Zn solutions (0, 250, 500, 750, and 1,000 mg l−1) in the first experiment, and We added the same zinc doses as mg kg−1 to the soil of the pots where the plants would grow in the second one. As a result, the inhibitory effects were more prominent in the early seedling stage (especially at 1,000 mg l−1 Zn) than in the germination one. We determined plant growth retardation, decreases in leaf water contents, and increases in membrane damages with higher Zn (≥500 mg kg−1) in the experiment conducted by potting soil. We detected decreases in chlorophyll parameters parallel with the increases in Zn. The alterations in plant zinc contents revealed the accumulation capacity of pot marigold in potting conditions. That TF value >1 in Zn treatments up to 500 mg kg−1 points to the efficiency limit of pot marigold as a Zn-accumulator plant.

Vertical distribution of heavy metals in core sediments from Kelantan River off Tanah Merah, Kelantan, Malaysia

Core sediments from two sampling points namely TM 2 and TM3 which are located at the Kelantan Rive near to Tanah Merah district had been collected to determine the vertical profile of heavy metals contents. TM 2 and TM3 were located near to gold mining area and agriculture area, respectively. The heavy metals in Tanah Merah were analysed using Atomic Absorption Spectrophotometer (AAS) PinA Acle 900F model. The degree of pollution has been investigated using Geo-accumulation (Igeo) index. For the result, the average value of heavy metals in Tanah Merah are Cu (12.67 ± 5.38 mg/kg), Pb (44.57 ± 8.75 mg/kg), Cr (56.69. ± 10.38 mg/kg), Zn (157.89 ± 88.56 mg/kg), Fe (4.08 ± 0.82 %) and Al (7.84 ± 1.53 %). The vertical profile of Cu and Zn at the bottom layer showed the decreasing trend toward the bottom of sediment suggesting the additional anthropogenic input of both metals to the sediment. In addition, most of the concentration value of Zn at TM2 near to gold mining set were exceed the permissible limit set by WHO. Furthermore, the result from the Igeo index also supported sediments at TM 2 which is located near to mining area are extremely contaminated with Cu and Zn. As conclusion, the authorities should closely monitor the level of pollution at the Kelantan River especially near to mining area.

Simulation of Zinc-diffused InAs cells for low temperature thermophotovoltaic systems

We simulated zinc-diffused InAs cells which used in the low-temperature thermophotovoltaic system under 600–1200 °C blackbody radiation. By analyzing some important parameters, such as surface recombination speed or thickness of different InAs cells, we achieve the optimal cell structure. The Zn diffusion process was experimented at Zn–In alloy sources at different temperatures for 2 h and a box-shaped Zn profile with a single hump was obtained. We also performed a simulation for optimized GaSb structure. Unlike InAs cells, the GaSb cells have been investigated for a long time under various temperatures, from which we have obtained a better structure and a maximal efficiency of 30%. However, the output power density of InAs cells is greater than that of GaSb cells when applied under low temperature heat source below 1200 °C. Its open circuit voltage and short circuit current density were measured as 0.1157 V and 3.786 A, and the output power density was 0.2222 W/cm2, which is better than 0.098 W/cm2 of GaSb cell under a blackbody temperature of 800 °C with anti-reflection coating and 13.7% grid area. The improved performance can be attributed to its lower bandgap and better quantum efficiency (QE) curves.

Advances in Understanding Mobilization Processes of Trace Metals in Marine Sediments.

Different mobilization mechanisms control the metal distribution in surface sediments of the Belgium coastal zone (BCZ) and the anoxic Gotland basin (GB). This mobilization was studied using DGT (diffusive gradients in thin films): vertical one-dimensional (1D) profiles of Cd, Co, Cu, Fe, Mn, Ni, Pb, and Zn were measured at 5 mm intervals, while two-dimensional (2D) high-resolution (100 μm) images of smaller zones of the sediment profile were obtained on separate DGT probes. Removal of dissolved Cd, Cu, and Pb in BCZ sediments caused steep vertical gradients at the sediment-water interface that were well replicated in 1D profiles and 2D images. While 1D profiles showed apparent coincident maxima of Co, Mn, and Fe, 2D images revealed mutually exclusive Co and Fe mobilization. Correlation analysis supported this observation and showed a consistent linkage between Co and Mn. Sharp maxima of some metals in the vertical 1D profiles of GB sediment were attributed to localized mobilization in microniches. Examination of an ∼1 mm diameter Cu and Ni maximum in 2D, defined by ∼300 data points, showed that the metals were supplied from localized decomposition of reactive organic material, rather than from reductively dissolving Fe or Mn oxides, and that they were removed as their sulfides.

Simultaneous determination of Fe and Zn in dried blood spot by HR-CS GF AAS using solid sampling

Dried Blood Spot (DBS) was evaluated as a solid sampling (SS) strategy for the simultaneous determination of Fe and Zn in blood samples by Solid Sampling High-Resolution Continuum Source Graphite Furnace Atomic Absorption Spectrometry (SS HR-CS GF AAS). The alternative lines of Fe and Zn at 307.572 and 307.589 nm, respectively, were evaluated. A good correlation between the area of DBS (in mm2) and volume of blood (in µL) was observed up to 200 µL of blood. A 3.4 mm diameter paper disk, equivalent 3.86 ± 0.13 µL, was punched from the DBS and employed for blood analysis. Random sampling through the area of the paper circle produced by 50 μL blood samples showed no chromatographic effects. The upside of the solid sampling 'boat type' graphite platform was coated with a W-based film. This coating allowed around 350 firings. The use of 3 µL of 15% v/v H2O2 solution as chemical modifier improved both the thermal stability and peak profile of Zn for aqueous medium (standard solution deposited onto Whatman paper), possibly because of the weakening of Zn-paper interactions or even by the formation of thermally more stable Zn oxides. Solid standards used for calibration in the 0.1–3.0 µg Fe and 5.0–50.0 ng Zn ranges were prepared with Whatman 903® paper discs impregnated with standard solutions of the analytes. Results for Fe and Zn determined by the proposed SS HR-CS GF AAS method were in agreement at a 95% confidence level (paired t-test) with those obtained by the comparative method (except for one sample) based on microwave-assisted acid digestion of blood and High-Resolution Continuum Source Flame Atomic Absorption Spectrometry (HR-CS F AAS). The limits of quantification were 10.2 mg/L (0.04 µg) for Fe and 1.2 mg/L (4.6 ng) for Zn. The relative standard deviation was < 10% (n = 12) for a sample containing 516 mg/L Fe and 8.7 mg/L Zn, and the sample throughput was equivalent to ca. 90 s per measurement.

Cation Effect of Chloride Salting Agents on Transition Metal Ion Hydration and Solvent Extraction by the Basic Extractant Methyltrioctylammonium Chloride.

The addition of a nonextractable salt has an important influence on the solvent extraction of metal ions, but the underlying principles are not completely understood yet. However, relating solute hydration mechanisms to solvent extraction equilibria is key to understanding the mechanism of solvent extraction of metal ions as a whole. We have studied the speciation of Co(II), Zn(II), and Cu(II) in aqueous solutions containing different chloride salts to understand their extraction to the basic extractant methyltrioctylammonium chloride (TOMAC). This includes the first speciation profile of Zn(II) in chloride media with the three Zn(II) species [Zn(H2O)6]2+, [ZnCl3H2O]−, and [ZnCl4]2–. The observed differences in extraction efficiency for a given transition metal ion can be explained by transition metal ion hydration due to ion–solvent interactions, rather than by ion–solute interactions or by differences in speciation. Chloride salting agents bearing a cation with a larger hydration Gibbs free energy reduce the free water content more, resulting in a lower hydration for the transition metal ion. This destabilizes the transition metal chloro complex in the aqueous phase and increases the extraction efficiency. Salting agents with di- and trivalent cations reduce the transition metal chloro complex hydration less than expected, resulting in a lower extraction efficiency. The cations of these salting agents have a very large hydration Gibbs free energy, but the overall hydration of these salts is reduced due to significant salt ion pair formation. The general order of salting-out strength for the extraction of metal ions from chloride salt solutions is Cs+ < Rb+ < NH4+ ≈ K+ < Al3+ ≈ Mg2+ ≈ Ca2+ ≈ Na+ < Li+. These findings can help in predicting the optimal conditions for metal separation by solvent extraction and also contribute to a broader understanding of the effects of dissolved salts on solutes.

Zn-Incorporated TiO2 Nanotube Surface Improves Osteogenesis Ability Through Influencing Immunomodulatory Function of Macrophages.

PurposeZinc (Zn), an essential trace element in the body, has stable chemical properties, excellent osteogenic ability and moderate immunomodulatory property. In the present study, a Zn-incorporated TiO2 nanotube (TNT) was fabricated on titanium (Ti) implant material. We aimed to evaluate the influence of nano-scale topography and Zn on behaviors of murine RAW 264.7 macrophages. Moreover, the effects of Zn-incorporated TNT surface-regulated macrophages on the behaviors and osteogenic differentiation of murine MC3T3-E1 osteoblasts were also investigated.MethodsTNT coatings were firstly fabricated on a pure Ti surface using anodic oxidation, and then nano-scale Zn particles were incorporated onto TNTs by the hydrothermal method. Surface topography, chemical composition, roughness, hydrophilicity, Zn release pattern and protein adsorption ability of the Zn-incorporated TiO2 nanotube surface were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), surface profiler, contact angle test, Zn release test and protein adsorption test. The cell behaviors and both pro-inflammatory (M1) and pro-regenerative (M2) marker gene and protein levels in macrophages cultured on Zn-incorporated TNTs surfaces with different TNT diameters were detected. The supernatants of macrophages were extracted and preserved as conditioned medium (CM). Furthermore, the behaviors and osteogenic properties of osteoblasts cultured in CM on various surfaces were evaluated.ResultsThe release profile of Zn on Zn-incorporated TNT surfaces revealed a controlled release pattern. Macrophages cultured on Zn-incorporated TNT surfaces displayed enhanced gene and protein expression of M2 markers, and M1 markers were moderately inhibited, compared with the LPS group (the inflammation model). When cultured in CM, osteoblasts cultured on Zn-incorporated TNTs showed strengthened cell proliferation, adhesion, osteogenesis-related gene expression, alkaline phosphatase activity and extracellular mineralization, compared with their TNT counterparts and the Ti group.ConclusionThis study suggests that the application of Zn-incorporated TNT surfaces may establish an osteogenic microenvironment and accelerate bone formation. It provided a promising strategy of Ti surface modification for a better applicable prospect.

Effects of Strontium incorporation to Mg-Zn-Ca biodegradable bulk metallic glass investigated by molecular dynamics simulation and density functional theory calculation

Molecular dynamics (MD) simulation and density functional theory (DFT) calculations were used to predict the material properties and explore the improvement on the surface corrosion resistance for the Mg66Zn30Ca3Sr1 bulk metallic glass (BMG). The Mg66Zn30Ca4 BMG was also investigated to realize the influence of the addition of Sr element on the material behaviors of Mg66Zn30Ca4. The Mg-Zn-Ca-Sr parameters of the next nearest-neighbor modified embedded atom method (2NN MEAM) potential were first determined by the guaranteed convergence particle swarm optimization (GCPSO) method based on the reference data from the density functional theory (DFT) calculation. Besides, using the 2NN MEAM parameters of the Mg-Zn-Ca-Sr system, the structures of Mg66Zn30Ca4 and Mg66Zn30Ca3Sr1 were predicted by the simulated-annealing basin-hopping (SABH) method. The local atomic arrangements of the predicted BMG structures are almost the same as those measured in some related experiments from a comparison with the calculated and experimental X-ray diffraction (XRD) profiles. Furthermore, the HA index analysis shows that the fractions of icosahedra-like local structures are about 72.20% and 72.73% for Mg66Zn30Ca4 and Mg66Zn30Ca3Sr1, respectively, indicating that these two BMG structures are entirely amorphous. The uniaxial tensile MD simulation was conducted to obtain the stress-strain relationship as well as the related mechanical properties of Mg66Zn30Ca4 and Mg66Zn30Ca3Sr1. Consequently, the predicted Young’s moduli of both BMGs are about 46.4 GPa, which are very close to the experimental values of 48.8 ± 0.2 and 49.1 ± 0.1 GPa for Mg66Zn30Ca4 and Mg66Zn30Ca3Sr1, respectively. However, the predicted strengths of Mg66Zn30Ca4 and Mg66Zn30Ca3Sr1 are about 850 and 900 MPa, both are slightly higher than the measured experimental values about 747 ± 22 and 848 ± 21 MPa for Mg66Zn30Ca4 and Mg66Zn30Ca3Sr1. Regarding the thermal properties, the predicted melting temperature of Mg66Zn30Ca3Sr1 by the square displacement (SD) profile is about 620 K, which is very close to the experimental melting temperature of about 613 K. The self-diffusion coefficients of Mg, Zn, Ca, and Sr elements were also calculated for temperatures near their melting points by means of the Einstein equation. The methodology can determine the diffusion barriers for different elements by utilizing these diffusion coefficients resulting in a fact that the diffusion barriers of Ca and Sr elements of Mg66Zn30Ca3Sr1 are relatively high. For the electronic properties predicted by the DFT calculation, the projected density of states (PDOS) profiles of surface Mg, Zn, Ca, and Sr elements clearly show that the addition of Sr into Mg66Zn30Ca4 effectively reduces the s and p orbital states of surface Mg and Zn elements near the Fermi level, particularly the p orbits, which suppresses the electron transfer as well as increases the surface corrosion resistance of Mg66Zn30Ca4. Consequently, this study has provided excellent 2NN MEAM parameters for the Mg, Zn, Ca, and Sr system by the GCPSO method to predict real BMG structures as well as by means of the DFT calculation to explore the electronic properties. Eventually, through our developed numerical processes the material properties of BMGs with different compositions can be predicted accurately for the new BMG design.

Spatial and Temporal Effects of Decommissioning a Zinc Smelter on the Sediment Quality of an Estuary System: Sepetiba Bay, Rio de Janeiro, Brazil

Sepetiba Bay, Rio de Janeiro, Brazil, was home to a zinc smelter until its shutdown in 1998, and during 2011 the remains of the smelter were decommissioned. This study investigates the impact of decommissioning on metal concentrations in the bottom sediments of the bay. In addition to Zn and Cd, Cr, Cu, Ni and Pb are also quantified. The results show that over these 15 years, Cd and Zn concentrations have decreased by 100 and 70%, respectively. Temporal effects are also studied by applying five dated 210Pb cores, which are validated using the Zn and Cd profiles. The observed decrease in the Zn concentration in oysters is correlated with its reduction in the sediment. It was possible to verify the impact of Cr, Cu, Ni and Pb on the sediment quality due to the remaining metallurgical industries in the Sepetiba Bay basin.