Different Concentrations Of Zn Research Articles

Towards a comprehensive understanding of zinc tolerance in Limonium brasiliense as a useful tool for environmental remediation and monitoring.

Heavy metal pollution is a serious environmental problem worldwide, creating the necessity to find eco-friendly strategies for monitoring and remediating environments. This study aimed to evaluate morphological, physiological, and biochemical responses as indicative of Zn tolerance in Limonium brasiliense and to determine the ability of this halophyte to accumulate different concentrations of Zn (0, 100, and 200 μM) in hydroponic conditions. The leaf shape at high Zn concentration showed enlarged petioles and lanceolate blades, whereas the leaf size was reduced. Water content, chlorophyll fluorescence parameters, and pigment content decreased with Zn addition. Of the antioxidant activities, only APx increased 75% compared to the control by Zn stress. Zn concentration was higher in aerial structures than in roots (BAC>1 and TF>1), suggesting that L. brasiliense could function as an accumulator of Zn. Its great ability to resist metal stress and its strong capacity to protect itself against high Zn concentration postulate it as a good phytoremediation of environments enriched with Zn. The study emphasizes using leaf morphology as an early biomonitoring tool for detecting Zn pollution, providing more evidence of their potential use as a biomarker for evaluating and assessing ecosystem health in biomonitoring programs.

Responses in Plant Growth and Root Exudates of Pistia stratiotes under Zn and Cu Stress.

At present, the situation regarding heavy metal pollution in aquatic environments is becoming more and more serious. The bioaccumulation of heavy metals in aquatic plants causes obvious phytotoxicity, which can also induce secondary pollution in the aquatic environment. Zinc and copper, as indispensable elements for plant growth, are also prominent heavy metals in water pollution in China, and their concentrations play a crucial role in plant growth. In this study, we investigated the response of Pistia stratiotes (P. stratiotes) to different concentrations of Zn and Cu, and the results showed that plant growth and photosynthesis were inhibited under both Zn (1, 2, 4, and 8 mg/L) and Cu (0.2, 0.4, 0.8, and 1 mg/L) stresses. The relative growth rates of P. stratiotes under 8 mg/L Zn or 1 mg/L Cu stress were 6.33% and 6.90%, which were much lower than those in the control group (10.86%). Meanwhile, Zn and Cu stress caused insignificant change in the relative water contents of plants. The decrease in phlorophyll fluorescence parameters and chlorophyll contents suggested the significant photoinhibition of Zn and Cu stress. Chemical analysis of plant root exudates showed that the root secretion species obtained by gas chromatography-mass spectrometry (GC-MS) mainly included amino acids, alkanes, aldehydes, ketones, phenols, and more. Compared with the control group, the influence of Zn or Cu on the reduction in relative amounts of exudates was greater than that on the increase. The results of this study provide important data for the utilization of P. stratiotes in heavy metal-polluted water environments.

Effects of Exogenous Zinc on Growth and Root Architecture Classification of Maize Seedlings Under Cadmium Stress

To explore the effects of different concentrations of zinc （Zn） on the growth and root architecture classification of maize seedlings under cadmium （Cd） stress， a hydroponic experiment was conducted to study the effects of different concentrations of Zn （0， 10， 25， 50， 100， 200， and 400 μmol·L-1） on the growth， root architecture and classification characteristics， Cd content， root Cd uptake capacity， and photosynthetic system of maize seedlings under Cd stress （50 μmol·L-1） by using Zhengdan 958 as the experimental material. Principal component analysis and the membership function method were used for comprehensive evaluation. The results showed that the 50 μmol·L-1 Cd stress had a significant toxic effect on maize seedlings， which significantly reduced chlorophyll content and photosynthetic parameters. The main root length， plant height， biomass， root forks， and root tips， including the root length and root surface area of the grade Ⅰ-Ⅲ diameter range and the root volume of the grade Ⅰ-Ⅱ diameter range， decreased significantly， which hindered the normal growth and development of maize seedlings. Compared with that under no Zn application， 100 μmol·L-1 and 200 μmol·L-1 Zn application reduced the uptake of Cd by maize seedlings， significantly reduced the Cd content in shoots and roots and the Cd uptake efficiency. The toxic effect on maize seedlings was alleviated， and the fresh weight， dry weight， tolerance index， and root forks of shoots and roots were significantly increased. The photosynthesis of maize seedlings was significantly enhanced， and the photosynthetic rate and the total chlorophyll content was significantly increased. The RL， SA， and RV in the Ⅰ-Ⅱ diameter range reached the maximum at 100 μmol·L-1 Zn， and the RL， SA， and RV in the Ⅲ diameter range reached the maximum at 200 μmol·L-1 Zn， which were significantly higher than those without Zn treatment. The comprehensive evaluation of the growth tolerance of maize seedlings showed that 100 μmol·L-1 and 200 μmol·L-1 Zn had better effects on alleviating Cd toxicity. Comprehensive analysis showed that the application of appropriate concentration of Zn could reduce the Cd content in maize seedlings， the Cd uptake capacity， and Cd uptake efficiency of roots； increase the biomass accumulation of maize seedlings； reduce the effect of Cd toxicity on root architecture； reduce the effect on the light and system； and improve the tolerance of maize seedlings to Cd.

Fe-Zn alloy, a new biodegradable material capable of reducing ROS and inhibiting oxidative stress.

Fe-based biodegradable materials have attracted significant attention due to their exceptional mechanical properties and favorable biocompatibility. Currently, research on Fe-based materials mainly focuses on regulating the degradation rate. However, excessive release of Fe ions during material degradation will induce the generation of reactive oxygen species (ROS), leading to oxidative stress and ferroptosis. Therefore, the control of ROS release and the improvement of biocompatibility for Fe-based materials are very important. In this study, new Fe-Zn alloys were prepared by electrodeposition with the intention of using Zn as an antioxidant to reduce oxidative damage during alloy degradation. Initially, the impact of three potential degradation ions (Fe2+, Fe3+, Zn2+) from the Fe-Zn alloy on human endothelial cell (EC) activity and migration ability was investigated. Subsequently, cell adhesion, cell activity, ROS production and DNA damage were assessed at various locations surrounding the alloy. Finally, the influence of different concentrations of Zn2+ in the medium on cell viability and ROS production was evaluated. High levels of ROS exhibited evident toxic effects on ECs and promoted DNA damage. As an antioxidant, Zn2+ effectively reduced ROS production around Fe and improved the cell viability on its surface at a concentration of 0.04 mmol/l. These findings demonstrate that Fe-Zn alloy can attenuate the ROS generated from Fe degradation thereby enhancing cytocompatibility.

Deciphering responses of sulfur autotrophic denitrification system to the single and joint stress of Zn(II) and dialkyldimethyl ammonium compounds: Performance, microbial community and different fractions of resistance genes

Zn(II) and dialkyldimethyl ammonium compounds (DADMAC) are common heavy metal and disinfectant contaminants in wastewater treatment plants. The response of sulfur autotrophic denitrification (SAD) system under single and joint stress with different concentrations of Zn(II) (1–25 mg/L) and DADMAC (0.2–10 mg/L) was evaluated using sequencing batch fixed-bed biofilm reactors in this study. The joint stress of high concentrations of Zn(II) and DADMAC had stronger inhibitory effects on microbial activity and metabolic function genes compared to the single stress, thus significantly inhibiting the performance of the SAD system. Furthermore, Zn(II) stress contributed to the proliferation of resistance genes (RGs) in water (w-RGs), whereas stress of DADMAC was able to induce the proliferation of intracellular RGs (si-RGs) and extracellular RGs (se-RGs) in sludge. And under the joint stress of Zn(II) and DADAMC, the abundances of si/se-RGs were much higher than that under single stress, with a higher risk of RGs transmission. The α-Helix/(β-sheet + random coil) in tightly bound extracellular polymeric substances correlated positively with si-tnpA-04 and se-tnpA-04. Horizontal gene transfer via mobile genetic elements was the main mode of RGs transmission. This work assessed the risk of DADAMC and Zn(II) in the SAD system and established new insights into the transmission of three-fraction RGs under DADMAC and Zn(II) stress.

Effects of exogenous zinc on the physiological characteristics and enzyme activities of Passiflora edulis Sims f. edulis seedlings.

Passionflower (Passiflora edulis Sims) is widely distributed in tropical and subtropical areas for edible, medicinal and skin care product processing, and the market demand is large. Zinc (Zn) is a necessary trace element for plant growth and development. In many countries, the content of Zn in soil is low and/or bioavailability is low. The exogenous application of Zn has become a common agronomic measure in agriculture. However, the effect of Zn on the physiological characteristics and enzyme activity of passionflower seedlings is not clear. In this study, pot experiments were conducted to analyse the effects of different concentrations of Zn (0, 200, 400, 800 mg kg-1) on the plant growth, photosynthetic pigments, osmotic regulators, membrane system and antioxidant enzyme system of purple passionflower (Passiflora edulis Sims f. edulis) seedlings, and Pearson correlation and principal component analyses were performed. The results showed that (1) the 200 mg kg-1 Zn treatment increased the contents of chlorophyll a (37.65%), chlorophyll b (41.22%), chlorophyll a+b (38.59%) and carotenoids (29.74%). The value of chlorophyll a/b changed little and had no effect on leaf growth. (2) The contents of proline (Pro) and malondialdehyde (MDA) in P. edulis Sims f. edulis seedlings treated with 400 mg kg-1 Zn increased significantly by 116.84% and 42.69%, respectively. The activities of catalase (CAT) and peroxidase (POD) increased by 16.82% and 18.70%, respectively. Superoxide dismutase (SOD), leaf area (LA), leaf perimeter (LP) and leaf width (LW) decreased significantly by 47.20%, 19.75%, 8.32% and 11.97%, respectively. (3) 800 mg kg-1 Zn significantly increased the contents of Pro (202.56%) and MDA (26.7%) and the activities of CAT (16.00%) and POD (67.00%), while the soluble sugar (SS), SOD, LA, LP and LW decreased significantly by 36.67%, 32.86%, 23.36%, 8.32% and 11.18%, respectively. (4) There was a significant positive correlation between Pro and photosynthetic pigments and between SOD and leaf growth and a significant negative correlation between POD and SS and between SOD and MDA. (5) A low concentration (200 mg kg-1) of Zn promoted the growth of P. edulis Sims f. edulis seedlings and allowed stress caused by high Zn concentrations to be tolerated. The results of this study can provide a reference for the application of Zn fertilizer to P. edulis Sims f. edulis.

High tolerance to zinc but no evidence for local adaptation in the aquatic plant Lemna minor

Duckweeds are a widely distributed and economically important aquatic plant family that have high potential for phytoremediation of polluted water bodies. We collected four ecotypes of the common duckweed Lemna minor from the four corners of Switzerland and assessed how their home versus away environments influenced their growth. Additionally, we investigated their response to a metal pollutant (zinc, Zn) in both their home and away environments. Zn is found in freshwater systems and can become harmful to plants at elevated concentrations. We hypothesized that growing in their home environment would help the plants buffer the negative effect of the metal pollutant. To test this, we measured Lemna growth in a common garden experiment in a glasshouse where the four ecotypes were grown in each of the water environments, as well as in three different concentrations of Zn. To investigate whether interactions between Lemna and its microbial community can enhance or reduce tolerance to heavy metal pollution, we sampled chlorophyll‐a as a proxy for algal biomass. Finally, we measured total nitrogen and total organic carbon to describe the abiotic environment in more detail.The four Lemna ecotypes exhibited significantly different growth rates across the water treatments. This difference in fitness was matched with DNA sequencing revealing genetic differentiation between the four ecotypes. However, the effect of the water and Zn treatment on Lemna growth was the same for all ecotypes. We did not find evidence for local adaptation; instead, we observed strong plastic responses. Lemna growth rates were higher under higher Zn concentrations. This positive effect of Zn on Lemna growth could be in part due to reduced competition with algae. We conclude that L. minor ecotypes may exhibit large differences in growth rate, but that the species overall has a high Zn tolerance and strong plastic adaptive potential in novel environments.

Higher cadmium and zinc accumulation in parsley (Petroselinum crispum) roots activates its antioxidants defense system.

Parsley (Petroselinum crispum) is herb with many biological and medicinal benefits for humans. However, growth on zinc (Zn) and cadmium (Cd) contaminated sites might get severely affected due to over accumulation of heavy metals (HM) in different plant tissues. Antioxidants play a crucial role in minimizing the negative effects of HM. The present study investigates the effects of Zn and Cd stress on P. crispum morphological parameters, enzymatic/non-enzymatic antioxidant profiling and metal accumulation in shoot/root. Plants were exposed to different concentrations of Zn (50, 100, 150 and 200µM) and Cd (10, 20, 40 and 80µM) along with control (no stress), in soil-less Hoagland's solution. The results showed that Zn and Cd substantially decrease the growth parameters with increased contents of malondialdehyde (MDA), hydrogen peroxide (H2O2), and electrolyte leakage (EL). Non-enzymatic antioxidant activities, like total phenolic contents (TPC) and ferric reducing antioxidant power (FRAP), were induced high in leaves only upon Cd stress and contrarilydecreased upon Zn stress. Total flavonoid contents (TFC) were decreased under Zn and Cd stress. Enzymatic antioxidant activities like superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were also strongly induced upon Cd stress. At the same time, SOD and guaiacol peroxidase (GPX) activity was induced significantly upon Zn stress. Cd uptake and accumulation was notably high in roots as compared to shoots, which suggests P. crispum have a reduced ability to translocate Cd towards aboveground parts (leaves). Additionally, strong induction of antioxidants by P. crispum under Cd stress might indicate the capacity to effectively re-modulate its physiological response. However, further investigations regarding other HMs and experiments at the molecular level are still needed.

Investigation of active laser delivery and antimycotic activity of zinc-containing nanomaterials and photodynamic drugs in the treatment of onychomicosis

One of the most common nail pathologies is onychomycosis, a fungal nail infection. The low efficiency of existing methods for the treatment of onychomycosis stimulates the search for new drugs and technologies for their delivery under the nail plate. The aim of the investigation was to study the possibility of using Er:YLF laser radiation for sequential laser microporation of the human nail plate and active laser delivery of modern photodynamic preparations and zinc-containing nanomaterials under the nail plate, as well as to determine their antimycotic activity against the Candida albicans fungus under photodynamic exposure with a wavelength of 656±10 nm. A 0.001 % aqueous solution of methylene blue, a chlorine-containing Revixan gel, as well as zinc-containing nanomaterials, which are aqueous solutions of polyvinylpyrrolidone gel with different concentrations of Zn(NO3)2 nanoparticles and acidity, were studied. It was established that the smallest number of laser pulses required for in vitro microporation of the nail plate and active laser delivery under the nail plate is required when using a 0.001 % aqueous solution of methylene blue, and the largest is required when using Revixan gel. For zinc-containing nanomaterials, an increase in the concentration of Zn(NO3)2 nanoparticles from 14 to 40 % leads to an increase in the number of laser pulses required for active drug delivery under the nail plate by 1.25 times, while a change in the acidity of the pH gel from 7.0 to 6.7 does not has a significant impact on it. It was found that all the studied drugs in combination with photodynamic action at a wavelength of 656±10 nm have an antimycotic effect on the Candida albicans fungus culture. The minimum growth rate of Candida albicans colonies was observed when using the Revixan gel, for which the antimycotic activity reached 73.8 %. The obtained results can be applied in the development of laser systems and technologies for the treatment of fungal diseases, including for photodynamic therapy of onychomycosis.

Characterizing Mammalian Zinc Transporters Using an In Vitro Zinc Transport Assay.

Transition metals such as Zn2+ ions must be tightly regulated due to their cellular toxicity. Previously, the activity of Zn2+ transporters was measured indirectly by determining the expression level of the transporter under different concentrations of Zn2+. This was done by utilizing immunohistochemistry, measuring mRNA in the tissue, or determining the cellular Zn2+ levels. With the development of intracellular Zn2+ sensors, the activities of zinc transporters are currently primarily determined by correlating changes in intracellular Zn2+, detected using fluorescent probes, with the expression of the Zn2+ transporters. However, even today, only a few labs monitor dynamic changes in intracellular Zn2+ and use it to measure the activity of zinc transporters directly. Part of the problem is that out of the 10 zinc transporters of the ZnT family, except for ZnT10 (transports manganese), only zinc transporter 1 (ZnT1) is localized at the plasma membrane. Therefore, linking the transport activity to changes in the intracellular Zn2+ concentration is hard. This article describes a direct way to determine the zinc transport kinetics using an assay based on a zinc-specific fluorescent dye, FluoZin-3. This dye is loaded into mammalian cells in its ester form and then trapped in the cytosol due to cellular di-esterase activity. The cells are loaded with Zn2+ by utilizing the Zn2+ ionophore pyrithione. The ZnT1 activity is assessed from the linear part of the reduction in fluorescence following the cell washout. The fluorescence measured at an excitation of 470 nm and emission of 520 nm is proportional to the free intracellular Zn2+. Selecting the cells expressing ZnT1 tagged with the mCherry fluorophore allows for monitoring only the cells expressing the transporter. This assay is used to investigate the contribution of different domains of ZnT1 protein to the transport mechanism of human ZnT1, a eukaryotic transmembrane protein that extrudes excess zinc from the cell.

Effects of Zinc Accumulation on Earthworm Aporrectodea caliginosa (Haplotaxida: Lumbricidae)

Earthworms are key to the earth's ecosystem, which helps the soil increase its fertility and repair its existing elements, as well as remove contaminants. This study investigated the accumulation of Zn in the earthworm Aporrectodea caliginosa after 15 days of exposure. The worms were grown in media with different concentrations of Zn between 750 and 1500 ppm. Each treatment consisted of three replicates, containing 30 worms. A control group without Zn was also used. Data were analyzed by using Duncan Multi–Range. The results revealed that A. caliginosa had a strong ability to accumulate Zn in its tissue compared to the control group. It was noticed that the increase of the heavy metal in the worm´s tissue is associated with the elevation of the metal in its media. The results show a significant loss of weight in the worm´s body and loss in the growth rate; they also shown a decrease in specific growth rate. Moreover, there was a significant decrease in the worm length, showing a high effect, especially after 15 days of breeding with all concentrations used in this study. The researchers recommend using earthworms to purify the soil from contaminants because earthworm has a great ability to get rid of all pollutants, whether metals or pesticides or parasites, especially in industrialized countries and agricultural lands.

Revealing Photocatalytic Performance of ZnxCd1-xS Nanoparticles Depending on the Irradiation Wavelength.

Photocatalysts are useful for various applications, including the conservation and storage of energy, wastewater treatment, air purification, semiconductors, and production of high-value-added products. Herein, ZnxCd1-xS nanoparticle (NP) photocatalysts with different concentrations of Zn2+ ions (x = 0.0, 0.3, 0.5, or 0.7) were successfully synthesized. The photocatalytic activities of ZnxCd1-xS NPs varied with the irradiation wavelength. X-ray diffraction, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, and ultraviolet-visible spectroscopy were used to characterize the surface morphology and electronic properties of the ZnxCd1-xS NPs. In addition, in situ X-ray photoelectron spectroscopy was performed to investigate the effect of the concentration of Zn2+ ions on the irradiation wavelength for photocatalytic activity. Furthermore, wavelength-dependent photocatalytic degradation (PCD) activity of the ZnxCd1-xS NPs was investigated using biomass-derived 2,5-hydroxymethylfurfural (HMF). We observed that the selective oxidation of HMF using ZnxCd1-xS NPs resulted in the formation of 2,5-furandicarboxylic acid via 5-hydroxymethyl-2-furancarboxylic acid or 2,5-diformylfuran. The selective oxidation of HMF was dependent on the irradiation wavelength for PCD. Moreover, the irradiation wavelength for the PCD depended on the concentration of Zn2+ ions in the ZnxCd1-xS NPs.

Study on the zinc ions binding to human lactoferrin

The article presents the results of the study of Zn2+ binding to recombinant human lactoferrin. Isotherm studies were utilized with subsequent fit to Langmuir, Freundlich, and Henry models. Moreover, the kinetics of the process was investigated with the use of pseudo-first, pseudo-second, and Weber-Morris models for the process description. The study results revealed the complex nature of Zn2+ binding to lactoferrin, where based on isotherm three different sorption steps can be distinguished. Based on isotherm three different concentrations of Zn2+ solution (60, 300, and 600 mg/L) were chosen for Zn-lactoferrin complexes synthesis for further investigations. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transmission electron microscopy, inductively coupled plasma mass spectrometry, Fourier-transform infrared and Raman spectroscopies were utilized which enabled the description of the Zn-binding process in a more accurate way. As a result, the highest Zn2+ content (7.92 mg/g) was observed for the complex synthesized with 600 mg/L Zn2+ solution. Spectroscopic studies reveal that the zinc ions binding may occur through the deprotonated carboxylic groups of aspartic and glutamic acids, imidazole ring of a histidine, or –CN and –OH groups of other amino acids as well as through weak noncovalent cation–π interactions. According to obtained results, it is also can be suggested that high Zn2+ concentration can lead to changes in protein structure and partial loss of Fe3+ from the metal-binding clefts. The obtained lab results were also complemented with Molecular Dynamics and Density Functional Theory simulations that support the conclusions outlined from lab experiments.

Psoralen synergies with zinc implants to promote bone repair by regulating ZIP4 in rats with bone defect

BackgroundThe regulation of dose-dependent biological effects induced by biodegradation is a challenge for the production of biodegradable bone-substitute materials, especially biodegradable zinc (Zn) -based materials. Cytotoxicity caused by excess local Zn ions (Zn2+) from degradation is one of the factors limiting the wide application of Zn implants. Given that previous studies have revealed that delayed degradation of Zn materials by surface modification does not reduce cytotoxicity; in the present study, we explore whether preventing the entry of excess Zn2+ into cells may can reduce local Zn toxicity by applying Psoralen (PRL) to Zn implants and assessing its ability to regulate intracellular Zn2+ concentrations.MethodsThe effects of different concentrations of Zn2+ on cellular activity and cytotoxicity were investigated; briefly, we identified natural compounds that regulate Zn transporters, thereby regulating the concentrations of intracellular Zn2+, and applied them to Zn materials. Of these materials, PRL, a natural, tricyclic, coumarin-like aromatic compound that promotes the proliferation and differentiation of osteoblasts and enhances osteogenic activity, was loaded onto the surface of a Zn material using peptides and chitosan (CS), and the surface characteristics, electrochemical properties, and activity of the modified Zn material were evaluated. In addition, the ability of Zn + CS/pPRL implants to promote bone formation and accelerate large-scale bone defect repairs was assessed both in vitro and in vivo.ResultsWe determined that 180 µM Zn2+ significantly induced pre-osteoblast cytotoxicity, and a 23-fold increase in Zrt- and Irt-like protein 4 (ZIP4) expression. We also found that PRL dynamically regulates the expression of ZIP4 in response to Zn2+ concentration. To address the problem of cytotoxicity caused by excessive Zn2+ in local Zn implants, PRL was loaded onto the surface of Zn implants in vivo using peptides and CS, which dynamically regulated ZIP4 levels, maintained the balance of intracellular Zn2+ concentrations, and enhanced the osteogenic activity of Zn implants.ConclusionsThis study reveals the importance of Zn2+ concentration when using Zn materials to promote bone formation and introduces a natural active ingredient, PRL, that can regulate intracellular Zn2+ levels, and thus may be clinically applicable to Zn implants for the treatment of critical bone defects.Graphical

Effects of different concentration of Zn(II) on the organic material degradation and nitrification process in the treatment of real industrial wastewater

Effects of different concentration of Zn(II) on the organic material degradation and nitrification process in the treatment of real industrial wastewater

THE TOXICITY OF ESSENTIAL ELEMENT (Zn) IN THE BLOOD PROFILE OF FRESH WATER TELEOST, CLARIAS BATRACHUS

Minerals such as zinc (Zn) are abundant in the Earth's crust, serving as cofactors for a variety of proteins and modulating immune functions, however, in high doses, it might cause toxic effects on the body. This study examined the effects of excessive Zn concentrations on fish hematological parameters. The authors employed fresh water fishes Clarias batrachus as an experimental model and treated them with three different concentrations of Zn. The treatment with Zn was done for total 28 days and hematological parameters were assessed at different time intervals. As compared to control, Zn treated fishes showed considerable changes in hematological parameters such as, Haemoglobin (Hb), total erythrocyte counts (TEC), total leucocytes count (TLC), erythrocyte sedimentation rate (ESR), packed cell volume (PCV), mean corpuscular haemoglobin (MCH) and mean corpuscular volume (MCV). The present study showed that exposure to Zn could be linked to chronic and acute hematological toxicity in fishes in time and dose-dependent manner.

THE TOXICITY OF ESSENTIAL ELEMENT (Zn) IN THE BLOOD PROFILE OF FRESH WATER TELEOST, CLARIAS BATRACHUS

Minerals such as zinc (Zn) are abundant in the Earth's crust, serving as cofactors for a variety of proteins and modulating immune functions, however, in high doses, it might cause toxic effects on the body. This study examined the effects of excessive Zn concentrations on fish hematological parameters. The authors employed fresh water fishes Clarias batrachus as an experimental model and treated them with three different concentrations of Zn. The treatment with Zn was done for total 28 days and hematological parameters were assessed at different time intervals. As compared to control, Zn treated fishes showed considerable changes in hematological parameters such as, Haemoglobin (Hb), total erythrocyte counts (TEC), total leucocytes count (TLC), erythrocyte sedimentation rate (ESR), packed cell volume (PCV), mean corpuscular haemoglobin (MCH) and mean corpuscular volume (MCV). The present study showed that exposure to Zn could be linked to chronic and acute hematological toxicity in fishes in time and dose-dependent manner.

ВПЛИВ Zn2+ ВОДНОГО СЕРЕДОВИЩА НА ДОБОВУ ЦИКЛІЧНІСТЬ ДИХАННЯ АЛОВИДІВ PLANORBARIUS CORNEUS S. L. (MOLLUSCA, GASTROPODA, PLANORBIDAE)

We investigated the impact of the different concentrations of Zn2+ in the water (in the 0.5 MPL – 3 MPL range) on the chronological features of lung and direct diffusive respiration in representatives of superspecies complex of ramshorns Planorbarius corneus s. l. (“eastern” and “western” allospecies) from the Ukrainian river network. They have a bimodal respiration. Atmospheric oxygen goes into their true lungs through the breathing pore – pneumostome, – during the periodical rises up to the water surface tension film. And the oxygen soluble in the water is acquired by the osmosis through the epithelial body coverings and the surface of adaptive gill. Both ways are almost equally important for the oxygen supply of mollusks’ organisms.
 Zn2+ ions are the powerful toxins of local effect for ramshorns. The excess of the MPL may lead to the impairment of stable homeostasis. Both P. corneus allospecies s. l. have clearly expressed diurnal cyclicality of their lung respiration (in the “day-night” rhythm). They perform 1.2–1.3 times more “inhales” during the day with the shorter (1.3–1.4 times) intervals. This apparently is the consequence of physiological activity increasing in the period of their most intensive life-giving metabolic processes occurring. 
 Under the 0.5 MPL of Zn2+ there were no statistically significant changes in lung and direct diffusive respirations indexes (comparing to the control) in both allospecies during the latent phase of their intoxication process. “Inhales” during the day were 1.1 time longer than during the night in experimental animals. This let mollusks replenish the amount of oxygen they underreceived due to the decreased number of night “inhales”.
 Under MPL Zn2+ level the respirational indexes of ramshorns (number, length and volume of “inhales” and intervals between them) increased in average 1.1 times. Their feeding and moving behaviors visibly activated, which promoted the increasing of the daily frequency of their respiration rhythm. Under the 2 MPL concentration of Zn2+ there was further significant increasing (p

Dislocation kinetics explains energy partitioning during strain hardening: Model and experimental validation by infrared thermography and acoustic emission

The energy dissipation and storage during strain hardening of metals have been investigated by means of complementary in situ techniques - infrared thermography (IRT), digital image correlation (DIC) and acoustic emission (AE). Inspired by experimental results obtained in the present work and data available in literature, we proposed the analytically tractable thermodynamic modelling approach, which is conceptually based on a single-variable dislocation evolution approach with a total dislocation density serving as a principal variable governing the strain hardening process. Unified by the kinetic approach involving generation, annihilation and motion of dislocations, the models accounting for the acoustic emission behaviour and heat dissipation under load have been proposed and verified experimentally. For the first time, we were able to demonstrate that the key parameters governing the dislocation storage and annihilation rates can be, in principle, recovered from independent AE and IRT measurements. These results agree favourably with the predictions of the dislocation-based constitutive strain hardening models of the Kocks-Mecking type. The self-consistency, versatility and predictive capacity of the proposed modelling approach are demonstrated in the examples of Cu–Zn alloys with different concentrations of Zn varied from 0 to 30% and correspondingly different stacking fault energies.

Biochar from Cyperus alternifolius Linn.: from a waste of phytoremediation processing to efficient depolluting agent.

Phytoremediation is one of the most powerful and viable solutions for developing countries to clean the soil and water bodies from metallic pollutants. Cyperus alternifolius Linn. (CAL), a tropical wetland plant, has been widely researched for removing harmful contaminants due to its hyperaccumulation ability. However, the waste biomass of phytoremediation processing may risk secondary environmental pollution. Thus, the preparation and application of biochar from metal-contaminated plants can be considered a new approach. In a 60-day experiment, CAL plants were irrigated with different concentrations of Zn(II) (200, 700, 1200, 1700, and 2200mg·L-1), and then the plants were converted into biochar via the pyrolysis process. The characteristics of biochar including of surface composition and morphology, phase formation, and optical property were analyzed. The biochar enriched with Zn(II) at 1200mg·L-1 had a bandgap value of 3.17eV and consisted of carbon microparticles intermingled with ZnO and SiO2 nanoparticles. Furthermore, the adsorption and photocatalysis of the biochar were studied in the discolouration of methylene blue (MB), as a test reaction, with the maximum MB removal capacities of 55.2mg·g-1. Such results will serve as the basis for new research aiming at the potential for reusing metal-contaminated plants to produce efficient depolluting biochar.