Increase In Zinc Content Research Articles

SWITCH TO GREEN METHODS FOR WASTE WATER MANAGEMENT

The proposed research work is indebted to the green solution for mitigation of water pollutant that was discharge from industries. In this modern era, water pollution caused by heavy metals is a serious concern to improve the quantity of drinking water. To solve this problem, an environmental friendly Zinc oxide (ZnO) photo catalyst has developed that is suitable for removal of arsenic impurities from wastewater originating from industries. ZnO is less hazardous metal oxide in compared to other mixed or metal oxide as increase in Zinc concentration has minimum impact on living organism, hence it is referred as green synthesis in this work. The physical characterization of zinc oxide performed using Scanning electron microscopy, Fourier Transform Infra-Red spectroscopy, Thermo gravimetric analysis, and X-ray diffraction analysis. To study the catalytic performance of ZnO, we have observed different O.D. values (at 380nm) for a series of ZnO solution ranging from control to 10%, 20% and 30% of ZnO. The photo catalytic activity was studied for 24 h with 10% and 20% ZnO (p H 7.8) at room temperature and it was found to be effective towards remediation of water pollution. It was found to be 78.46% in case of 10% ZnO and 78.04 % for 20% ZnO solution. Therefore, ZnO photocatalyst is proven to be an ecofriendly, and cost effective technique for water pollution mitigation.

Distribution, structure, and mineralization of calcified cartilage remnants in hard antlers

Antlers are paired deciduous bony cranial appendages of deer that undergo a regular cycle of growth, death and casting, and constitute the most rapidly growing bones in mammals. Antler growth occurs in an appositional mode and involves a modified form of endochondral ossification. In endochondral bones, calcified cartilage is typically a transient tissue that is eventually completely replaced by bone tissue. We studied the distribution and characteristics of calcified cartilage in hard antlers from three deer species (Capreolus capreolus, Cervus elaphus, Dama dama), i.e., in antlers from which the skin (velvet) had been shed. Remnants of calcified cartilage were regularly present as part of the trabecular framework in the late formed, distal antler portions in all three species, whereas this tissue was largely or completely missing in the more proximal antler portions. The presence of calcified cartilage remnants in the distal antler portions is attributed to the limited antler lifespan of only a few months, which is also the reason for the virtual lack of bone remodeling in antlers. The calcified cartilage matrix was more highly mineralized than the antler bone matrix. Mineralized deposits were observed in some chondrocyte lacunae and occasionally also in osteocyte lacunae, a phenomenon that has not previously been reported in antlers. Using synchrotron radiation-induced X-ray fluorescence (SR-XRF) mapping, we further demonstrated increased zinc concentrations in cement lines, along the inner borders of incompletely formed primary osteons, along the walls of partly or completely mineral-occluded chondrocyte and osteocyte lacunae, and in intralacunar mineralized deposits. The present study demonstrates that antlers are a promising model for studying the mineralization of cartilage and bone matrices and the formation of mineralized deposits in chondrocyte and osteocyte lacunae.

High Temperature-Induced Oxidative Stress Affects Systemic Zinc Homeostasis in Broilers by Regulating Zinc Transporters and Metallothionein in the Liver and Jejunum.

To investigate the change in zinc homeostasis of broilers under heat stress, 512 broiler chickens were raised to the age of 28 days. The broilers were then assigned to heat stress and normal temperature (36.0°C vs. 26.0°C) groups for 7 days. The results showed that oxidative stress induced by high temperature had a negative effect on the growth performance of broilers. Heat stress altered zinc homeostasis and led to a redistribution of zinc in broilers, which was reflected in increased zinc concentrations in the jejunum, liver, and tibia. Upregulation of the expression of the zinc exporter ZnT1 and importers ZIP8 and ZIP14 in the jejunum indicated that more zinc was absorbed and transported from the jejunum into the blood, while the liver increased its capacity to hold zinc through upregulation of metallothionein (MT) expression, which was achieved by reducing ZnT1 expression and upregulating the expression of the importer ZIP3. The pathway was mediated by zinc transporters, but the capacity of MT to chelate and release zinc ions also played a crucial role. The mechanism of alterations in zinc homeostasis under heat stress was revealed by the changes in zinc transporters and MT levels in the intestine and liver. Heat stress also altered cecal microbial diversity and reduced the relative abundances of Bilophila and Dialister. In conclusion, broilers altered systemic zinc homeostasis through the regulation of zinc transporters and MT in the liver and jejunum to resist oxidative stress induced by high temperature.

Construction of polysaccharide based physically crosslinked double-network antibacterial hydrogel

Most hydrogels are chemically crosslinked hydrogels, the use of excessive chemical crosslinkers limits their application in biomedicine and other fields. Herein, a completely physically crosslinked double-network hydrogel of sodium alginate/chitosan/zinc ion (SA/CS/Zn2+ PDH) which does not contain toxic chemical reagents was prepared. Compared with the sodium alginate/chitosan single-network hydrogel crosslinked by electrostatic interactions, the mechanical properties of the PDH is significantly improved. Gelation time, swelling behavior, mechanical performance, and antibacterial ability were evaluated with zinc concentration as a variable. It was found that with the increase of zinc content, the gelation rate increased, the swelling rate decreased, and the mechanical properties improved. The PDH exhibited outstanding antibacterial activity against both Staphylococcus aureus and Escherichia coli. Our work provides a new idea for the fabrication of environment-friendly physically crosslinked double-network hydrogels based on natural polysaccharides.

The impact of chronic exposure to MLX i3Dome on people under stress: effects on body detoxification, immune function, and mood state

ABSTRACT Using a parallel randomised control trial to demonstrate the effectiveness of 10 sessions of a Triple Combined Intervention (TCI, far-infrared, negative air ions and light therapy) in reducing stress-related symptoms in workers and detoxify the body. Twenty-one participants were randomly assigned to the experimental group (Gexp, N = 11) or the control group (Gcon, N = 10). The Gexp completed 10 × 20 min sessions using the MLX i3Dome over a 4-week period. Subjective questionnaires were assessed for sleep and psychological disturbances. Trace elements, toxic metals, cortisol, white blood count, muscular and joint soreness level (SL), body weight, resting blood pressure and well-being were also measured. Systolic blood pressure was lower after the 4-week period for Gexp participants only. Sleep improved for Gexp participants and insomnia index decrease significantly. The increase in zinc and copper concentrations were associated with a decrease in the level of lead, mercury and cortisol in the blood following the 10-session programme. An increase in lymphocyte count was reported in the Gexp only. Initial evidence suggests that a triple combined intervention (i.e. MLX i3Dome) reduces excessive stress, improves perceived sleep quality, increases general well-being, enhances body detoxification.

Introduced oxygen vacancies in cadmium ferrite anode materials via Zn2+ incorporation for high performance lithium-ion batteries

Cationic substitution strategy was recognized as an effective approach to create a defective structure and increase the oxygen vacancies in the crystal structure for improving the electrochemical performance of Li-ion batteries components. In this study, ZnxCd1-xFe2O4 nanoparticles were synthesized via a facile inexpensive process at low temperature. The collected XRD data confirmed the formation of cubic structure with Fd3m space group. HR-TEM investigations showed the size enlargement of spherical-like crystals with increasing the concentration of doping Zn2+ ion. FESEM and BET measurements indicated the conversion of micropores in pure CdFe2O4 into mesopores and macropores in Zn-doped CdFe2O4 samples. XPS results of O1s spectra elucidated that Zn-doped CdFe2O4 samples have higher conductivity due to the created lattice defects and oxygen species. Zn-doped CdFe2O4 anodes exhibit great improvement in their initial discharge capacities ∼1618 and 1880 mAhg−1 upon substitution of Cd with 5% and 10% Zn, respectively. Furthermore, 10% Zn-doped CdFe2O4 anode displayed the highest Li-ions diffusion coefficient and exchange current density due to the enhanced Li+ ions mobility. The increase in zinc content (0.0–0.1) led to a decrease in the DC activation energy from 0.11 to 0.09 eV.

Integrated Membrane Process Coupled with Metal Sulfide Precipitation to Recover Zinc and Cyanide

In gold cyanidation plants, which include a zinc cementation process, there is a progressive increase in zinc content in the solution and a higher cyanide concentration in leaching tailings. Consequently, there are opportunities to: (i) recover zinc and cyanide from these solutions, (ii) generate a saleable ZnS by-product, and (iii) reduce cyanide consumption and cyanide concentration in leaching tailings. Previous studies have proposed the use of the SART (Sulfidization, Acidification, Recycling, and Thickening) process for this purpose; however, this process has disadvantages that must be addressed. This study presents the results of the experimental assessment of an alternative process, the SuCy process, which uses an integrated membrane process. The SuCy process is composed of a metal sulfide precipitation coupled with a membrane filtration stage, a membrane contactor step to recover and concentrate cyanide, and a final neutralization and ultrafiltration stage. The flux obtained for zinc sulfide separation was around 0.01 L/m2s, with cyanide recovery of 95% at 60 min, whereas flux for ultrafiltration was 0.22 L/m2s. A comparison with an experimental study of the SART process at laboratory scale showed that the SuCy process could obtain a higher zinc recovery and can reduce the solid–liquid separation equipment by around five times. Therefore, the SuCy process could be a promising alternative for zinc and cyanide recovery in gold cyanidation.

The effect of calcium carbonate content on the zinc quantity-intensity relationship in some soils of Mosul, Irak

The quantity-intensity relationship (Q/I) was used to evaluate thermodynamic parameters of zinc in soils under different agricultural management. Ten soil samples were collected from Mosul city to study zinc distribution of calcium carbonate content in these soils. Generally, Q/I relationship of zinc may provide an index for the strength and quantity of effective zinc supply to plants in soils. The Q/I parameters of zinc were studied to quantify zinc release before and after removing carbonates in the studied soils. Results showed that the zinc activity ratio (AReZn) is related to changes with labile zinc (±ΔZn) at equilibrium and increased together with increasing zinc concentrations, intensity (I) ranged between 0.8584 and 0.9972×10-3 mol/L1/2 before removing carbonates and between 0.0909 and 2.7626×10-3 mol/L1/2 after removing carbonates. The ranges of labile Zinc (ZnL) values before and after removing carbonates were between 0.5755-0.7815 and 0.0009-0.0104 cmol/kg, respectively, while the Zinc (PBCZn) before and after removing carbonates fluctuated from 0.5839 to 0.9104 and 0.00112 to 0.00990 cmol/kg(mol/L)−1/2, respectively. That means calcium carbonate increases exchangeable zinc and zinc capacity at equilibrium conditions. The free energy (−ΔF) ranged between -1.001 and -0.979 kJ/mol before removing carbonates and between -1.319 and -0.841 kJ/mol after removing carbonates. Gapon Selectivity Coefficient (kG) ranged between 0.0193835 and 0.027453 and 0.000045 and 0.00450 (mol/L)1/2 before and after removing carbonates, respectively. Therefore, these results may be used as a reference for zinc soil fertilization, whereas thermodynamic parameters values may be used to predict soil ability to supply available zinc.

Serum Trace Elements Concentrations in Patients with Restless Legs Syndrome.

Increased brain and serum zinc levels in patients with idiopathic restless legs syndrome (idiopathic RLS or iRLS) were described when compared with controls, suggesting a possible role of zinc in the pathogenesis of this disease. However, serum magnesium, calcium, manganese, iron, and copper levels of RLS patients were similar to controls, suggesting a specific impairment of zinc-dependent metabolism in RLS. The aim of this study is to assess the serum concentrations of trace elements involved in oxidative stress or causing peripheral nerve toxicity in a large series of patients with iRLS and controls. We determined serum levels of iron, copper, manganese, zinc, magnesium, selenium, calcium, aluminium, lead, cadmium, arsenic and mercury in 100 patients diagnosed with iRLS and in 110 age- and sex-matched controls using Inductively Coupled Plasma Mass Spectrometry. Serum copper, magnesium, selenium, and calcium concentrations were significantly higher in RLS patients than in controls. These differences were observed both in men and women. There were no major correlations between serum trace metal concentrations and age at onset of RLS or RLS severity, nor was there any association with a family history of RLS or drug response. This study shows an association between increased serum concentrations of copper, magnesium, selenium, and calcium with RLS in a Spanish Caucasian population and does not confirm the previously reported increase in serum zinc concentrations in patients suffering from this disease, suggesting that the different accuracy of the analytical methods used could have influenced the inconsistent results found in the literature.

Biofortified Wheat Increases Dietary Zinc Intake: A Randomised Controlled Efficacy Study of Zincol-2016 in Rural Pakistan.

A new variety of zinc biofortified wheat (Zincol-2016) was released in Pakistan in 2016. The primary aim of this study was to examine the effects of consuming Zincol-2016 wheat flour on biochemical and functional markers of zinc status in a population with widespread zinc deficiency. An individually-randomised, double-blind, placebo-controlled cross over design was used. Fifty households were recruited to participate in the study, with each household included at least one woman of reproductive age (16–49 years) who was neither pregnant nor breast feeding or currently taking nutritional supplements. All households were provided with control flour for an initial 2-week baseline period, followed by the intervention period where households were randomly allocated in a 1:1 ratio to receive biofortified flour (group A; n = 25) and control flour (group B; n = 25) for 8-weeks, then switched to the alternate flour for 8-weeks. The trial has been registered with the ISRCTN (https://www.isrctn.com), ID ISRCTN83678069. The primary outcome measure was plasma zinc concentration, and the secondary outcome measures were plasma selenium and copper concentrations, plasma copper:zinc ratio and fatty acid desaturase and elongase activity indices. Nutrient intake was assessed using 24-h dietary recall interviews. Mineral concentrations in plasma were measured using inductively coupled plasma mass spectrometry and free fatty acids and sphingolipids by mass spectrometry. Linear Mixed Model regression and General Linear Model with repeated measures were used to analyse the outcomes. Based on an average flour consumption of 224 g/day, Zincol-2016 flour provided an additional daily zinc intake of between 3.0 and 6.0 mg for white and whole grain flour, respectively. No serious adverse events were reported. This resulted in significant, increase in plasma zinc concentration after 4 weeks [mean difference 41.5 μg/L, 95% CI (6.9–76.1), p = 0.02]. This was not present after 8 weeks (p = 0.6). There were no consistent significant effects of the intervention on fatty acid desaturase and elongase activity indices. Regular consumption of Zincol-2016 flour increased the daily zinc intake of women of reproductive age by 30–60%, however this was not associated with a sustained improvement in indices of zinc status.

Lack of ZnT8 protects pancreatic islets from hypoxia- and cytokine-induced cell death.

Pancreatic β-cells depend on the well-balanced regulation of cytosolic zinc concentrations, providing sufficient zinc ions for the processing and storage of insulin, but avoiding toxic effects. The zinc transporter ZnT8, encoded by SLC30A8,is a key player regarding islet cell zinc homeostasis, and polymorphisms in this gene are associated with altered type 2 diabetes susceptibility in man. The objective of this study was to investigate the role of ZnT8 and zinc in situations of cellular stress as hypoxia or inflammation. Isolated islets of WT and global ZnT8−/− mice were exposed to hypoxia or cytokines and cell death was measured. To explore the role of changing intracellular Zn2+ concentrations, WT islets were exposed to different zinc concentrations using zinc chloride or the zinc chelator N,N,N′,N′-tetrakis(2-pyridinylmethyl)-1,2-ethanediamine (TPEN). Hypoxia or cytokine (TNF-α, IFN-γ, IL1-β) treatment induced islet cell death, but to a lesser extent in islets from ZnT8−/− mice, which were shown to have a reduced zinc content. Similarly, chelation of zinc with TPEN reduced cell death in WT islets treated with hypoxia or cytokines, whereas increased zinc concentrations aggravated the effects of these stressors. This study demonstrates a reduced rate of cell death in islets from ZnT8−/− mice as compared to WT islets when exposed to two distinct cellular stressors, hypoxia or cytotoxic cytokines. This protection from cell death is, in part, mediated by a reduced zinc content in islet cells of ZnT8−/− mice. These findings may be relevant for altered diabetes burden in carriers of risk SLC30A8 alleles in man.

Содержание тяжёлых металлов в компонентах малой реки, не подверженной влиянию антропогенной деятельности

The article presents the results of the analysis of surface waters, bottom sediments and muscles of the silver carp (Carassius auratus gibelio) from the upper reaches of the Olgokhta River. The results of laboratory studies have shown that the content of nutrients (NH4+, NO3-, NO2-, PO43-) in the river water does not exceed the maximum permissible values.Heavy metals (Fe, Mn, Zn, Pb, Cu and Ni) in river water, with the exception of iron and manganese, are within the MPC. The high concentrations of Fe and Mn are explained by the peculiarity of the Burein geochemical province. The increased zinc content in bottom sediments is explained by the increased geochemical activity of this metal. The content of heavy metals in the muscles of carp compared to other rivers in Russia is one of the lowest. Presumably, zinc and iron accumulate most in the muscles. The data obtained on the composition and quality of water, bottom sediments, as well as the concentration of metals in the muscles of the silver carp can be considered background for the region due to the absence of anthropogenic load on the watercourse.

ОЦЕНКА ЗАГРЯЗНЕНИЯ ТЯЖЕЛЫМИ МЕТАЛЛАМИ ПОЧВ ГОРОДА ПЕТРОПАВЛОВСКА-КАМЧАТСКОГО, КАМЧАТСКИЙ КРАЙ

The results of determining the gross content of zinc, copper and lead in the surface soil layer, collected in Petropavlovsk-Kamchatsky, are presented in the paper. Based on them the heavy metal pollution degree assessment in different places of the city during 2017–2020 is given. It was found that almost everywhere the lead content in soils corresponded to a very high or high degree of contamination. According to the concentration of copper and zinc, the soils were classified as low and medium polluted. During 2017–2020 an increase of copper and zinc concentration in soils was registered. The dynamics of changes in lead concentration, on the contrary, was poorly expressed during 2017–2018. In 2020 a decrease in its content was found in all observed areas. According to the integrated pollution indexes PLI and NPI, the most polluted soils were identified in such areas as ‟Hospital” (2017),‟Botanicheskiy Pereulok” (2018), ‟Stadium Spartak” (2020). All city soils were characterized by a weak degree of potential environmental risk resulting from heavy metal pollution. The obtained data can be used to monitor heavy metal contamination of urbanized territories soils in Kamchatka Territory.

Synthesis and role of structural disorder on the optical, magnetic and dielectric properties of Zn doped NiFe2O4 nanoferrites

Nanoferrites of the chemical formula Ni1-xZnxFe2O4 (0 ≤ x ≤ 0.6) were synthesized via the sol-gel auto combustion process. All the samples were extensively characterized to explore the influence of zinc doping on several physical properties. The detailed analysis of the XRD data confirms the cubic spinel structure of the compositions. The lattice constants and unit cell volume as computed by the Rietveld refinement program are found to follow the Vegard's law. Crystallite sizes of the samples as calculated through Scherrer equation and Williamson-Hall method decrease upon Zn doping in NiFe2O4. The formation of spinel phase was further confirmed by the characteristics bands in FTIR spectra. The well defined spherical morphology and narrow size distribution of the particles together with the purity of synthesized samples were examined by the scanning electron microscopy (SEM) along with energy dispersive x-ray (EDX) analysis. Raman spectra divulge the tetrahedral and octahedral sites in the structure and infer the successful Zn2+doping and replacement of Fe3+ ions from the tetrahedral sites. The optical bandgap and other parameters were calculated by the UV–visible absorption spectra that reveal considerable increase in the band gap of the samples on account of Zn doping. The frequency dependent dielectric investigations show distinct behavior of dielectric constant and an increase in loss tangent on increasing zinc concentration. The ac conductivity enhances with the increase in dopant concentration and attributed to the electron-hole hopping mechanism. The Nyquist plots revealed incomplete and partial semicircular curves for all compositions, signifying a non-Debye type of relaxation mechanism in the system. Field-dependent magnetization predicts ferromagnetic behavior with a narrower hysteresis loop for the samples of higher zinc concentration. An increase is observed in saturation magnetization (Ms) and coercivity (Hc) till 20% zinc content, while further doping reduces these parameters. This effect was elaborated by metal cations distribution into the tetrahedral and octahedral sites.

Nanofibrous matrix of polycaprolactone embedded with zinc/vanadate doped hydroxyapatite: Mechanical and in vitro cellular growth

The sequence of co-doped hydroxyapatite (HAP)/polycaprolactone (PCL) nanofibrous composites was prepared with different amounts of zinc. X-ray diffraction and Infrared techniques were approved for both Zn/V-HAP and Zn/V-HAP@PCL composites formation. The morphological and mechanical behaviors were considered. The 0.8Zn/V-HAP composite offers the smallest grains almost with a slight appearance of aggregates, besides small shallow pores with a highly rough surface. Its grain size starts from 0.13 to 0.9 μm. On the other hand, zinc ions cause fiber size homogeneity and reduction that the 0.8Zn/V-HAP composite is sized from 1.1 to 1.75 μm. Zinc incorporation into HAP powder causes a significant rise in surface roughness. Moreover, tensile strength records its maximum value of 5.00 ± 0.32 MPa in 0.6Zn/V-HAP@PCL, while it declines for 0.8Zn/V-HAP@PCL to 4.94 ± 0.22 MPa. Additionally, the nanofibrous composite (0.0Zn/V-HAP@PCL) shows a contact angle of 100°±3, while the angle becomes narrower with increasing zinc content till reaching 83°±2 for the composition of 0.8 Zn/V-HAP@PCL scaffolds. Cell viability shows excellent potential in the absence of zinc with 92.4 ± 1%, while zinc contribution offers higher performance, reaching 98.4 ± 4% in 0.8Zn/V-HAP@PCL nanofiber. The scaffolds with the highest zinc content (0.8 Zn/V-HAP@PCL) record an inhibition zone of 22.1 ± 1.3 and 21.1 ± 1.1 mm against Escherichia coli and Staphylococcus aureus, respectively. Regarding cell attachment, zinc addition and amounts introduce manipulating tools and significant improvement in proliferation potential upon the whole fiber. Thus the previous data is recommended these scaffolds for more research in biological applications.

Influence of Zinc on Nonisothermal Gasification Kinetics of Coke in a Blast Furnace.

The effect of zinc on the kinetics of coke gasification was studied by a nonisothermal method. The results indicated that with the increase of zinc content, coke gasification tended to move to the low-temperature zone, it occurred earlier, and the reaction rate increased. The main curve fitting method was used to analyze the mechanism function of coke gasification before and after adding zinc. The modified shrinking core model was found to be the optimal mechanism function for coke gasification, with which the kinetic parameters obtained showed that the pre-exponential factor and apparent activation energy of coke gasification decreased significantly with the increase of zinc adsorption amount. Moreover, a kinetic compensation effect was found to exist in the effect of zinc on coke gasification. Combined with X-ray diffraction (XRD) and the peak fitting technique, it was found that the difference in the catalytic effect of zinc on coke gasification was attributed to the carbon structure.

Intracellular zinc during cell activation and zinc deficiency

IntroductionZinc is an essential trace element having manifold functions within living cells. Zinc deficiency but also zinc excess impairs cell-specific functions whereas a balanced zinc level is required for an adequate cell behavior. Material and methodsThis study deals with the impact of cellular priming due to stimulation with interleukin (IL)-1, IL-2, IL-4, IL-6 or the chemokine CXCL12a and its subsequent influence on the intracellular free zinc concentration. Since cellular priming and activation is essential for proper immunological reactions, and across that highly cell-type specific, we investigated T cells, B cells, and peripheral blood mononuclear cells (PBMCs). Additionally, alterations of the intracellular zinc content was investigated by inducing zinc deficiency using the zinc chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethane-1,2-diamine (TPEN) with subsequent re-supplementation of zinc, hence generating an intracellular zinc flux. Evaluation of zinc staining with FluoZin3-AM, Zinpyr-1 and Zinquin was done by flow cytometry or by fluorescence microscopy. ResultsOur results indicate that cellular priming for different periods of time (10 minutes/one hour) causes decreased intracellular free zinc concentrations in the FluoZin3-AM staining and increased zinc concentrations stained with Zinpyr-1. Furthermore, zinc supplementation after induced zinc deficiency leads to a fast and excessive rise of the intracellular free zinc levels in most cellular compartments. ConclusionOur study emphasizes the importance of zinc homeostasis and zinc distribution during cellular priming and for certain signaling cascades especially in T and B cells. Moreover, we demonstrated that zinc re-supplementation of zinc deficient cells results in significantly elevated intracellular free zinc concentrations compared to untreated controls. Hence, this underlines the need of a balanced zinc homeostasis for proper immune cell function.

Structure and magnetic state of hydrothermally prepared Mn-Zn ferrite nanoparticles

Magnetic behaviour of nanoparticles deviates from their bulk equivalents not only due to finite-size and surface effects but it may be also affected by occurrence of metastable states, such as non-equilibrium cation distribution. The chemical composition along with the specific cation distribution are decisive for magnetic properties of spinel ferrites, the nanoparticles of which can be easily tailored to exhibit peculiar properties suitable for various applications. The present study is devoted to hydrothermally prepared MnZn ferrite nanoparticles; namely to five samples with approximate composition Mn1−xZnxFe2O4, where x = 0.21–0.63, that were prepared by a surfactant-free hydrothermal procedure at a rather low temperature of 180 °C. XRD measurements evidenced the cubic spinel structure and a gradual decrease of the mean crystallite size from 14 to 10 nm with increasing zinc content, which was further confirmed by TEM analysis. 57Fe Mössbauer spectroscopy and temperature-variable magnetic measurements provided valuable insight into the blocking behaviour of particles on two dramatically different time scales and demonstrated that Néel relaxation can be enhanced by increasing the zinc content. Nanoparticles of the selected composition Mn0.62Zn0.41Fe1.97O4 were subjected to neutron diffraction study at 2 K to determine the ferrimagnetic order and in combination with Mössbauer spectroscopy to analyse the cation distribution. The non-zero occupancy of Zn2+ in octahedral sites evidenced a metastable distribution, and the supplemental DFT study revealed that the distribution of Mn2+ is non-equilibrium as well.

Zinc containing calcium phosphates obtained via microwave irradiation of suspensions

Hydroxyapatite (HA) is a synthetic bio-ceramic very much like biological apatite which is the mineral constituent of bone. Biological apatite, however, varies in chemical composition with the presence of several additional ions such as Mg+2, Zn+2, Mn+2, Na+, K+, Sr+2, CO3−2, HPO4−2, F−1 and SiO4−4. These ions are responsible for specific biological functions; therefore, their substitution into the HA lattice is of interest. Zinc (Zn+2) is of interest due to its presence in all biological tissues and role in various biological functions. Traditional methods for synthesis of phase pure or substituted HA are either time consuming or require expensive methodologies. Traditional co-precipitation method often requires ageing time up to 24 h or more, in order to ensure that the precipitated amorphous apatitic phase attains stoichiometry ratio (i.e. Ca:P molar ratio of 1.67). Stochiometric ratio also plays an important role in thermal stability. It was envisaged that microwave irradiation of pre-precipitated suspensions can be used as a quick route for synthesis of zinc substituted calcium phosphates. This study, therefore, explores the possibility of incorporating zinc into the apatitic structure, the effect of zinc concentration and temperature on phase-purity and morphology. Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Fourier Transform Infra-Red Spectroscopy were used to characterize the materials. Increasing zinc content influenced phase-purity and thermal stability of the resulting material.

Induction of sex ratio change and intersex in Tegillarca granosa (Bivalvia: Arcidae) by waterborne zinc exposure

This study aims to investigate the effect of zinc on the sex ratio and intersexuality of Tegillarca granosa, a sequential hermaphroditic bivalve that undergoes sex change during the gonadal inactive stage. Groups of T. granosa in the gonadal inactive stage were first exposed to zinc under indoor aquarium conditions for 5 weeks, and then under wild conditions for 3 months. The proportion of males and females tended to increase and decrease, respectively as the zinc concentration increased. Intersexuality increased with an increase in zinc concentration, and occurred more in female than male groups in all zinc exposed groups. The intersex of T. granosa exposed to zinc could be divided into interfollicular and intrafollicular types according to the histological pattern. The results of this study suggest that zinc exposure higher than a certain concentration may induce male sexuality during the gonadal inactive stage in the same population of T. granosa, and could result in unequal sex ratios as well as intersex.