Distribution Of Zinc Research Articles

The ancient alarmone ZTP and zinc homeostasis in Bacillus subtilis

In Bacillus subtilis a sophisticated regulatory circuit that involves Z nucleoside triphosphate (ZTP) is recruited to optimize cellular zinc distribution when cytoplasmic zinc is scarce. This process uses enzymatic reactions to measure the pool of available zinc ions and amplifies this signal to control the activity of zinc chaperones. The ZTP-dependent regulatory circuit that is exploited for zinc homeostasis controls purine and folate biosynthesis, which starts with GTP as initial substrate. Low concentrations of formyl-tetrahydrofolate (fTHF) lead to accumulation of the intermediate 5'-phosphoribosyl-4-carboxyamide-5-aminoimidazole (AICAR or ZMP), which is pyrophosphorylated by another intermediate to ZTP. This alarmone activates expression of genes using a ZTP-dependent riboswitch in many bacterial strains. In this way, the cellular folate concentration controls folate biosynthesis via the enzymatic activity of the fTHF-dependent AICAR-transforming reaction. Zinc distribution control is layered onto this circuit. The 'sensor' is the activity of the initial reaction of folate synthesis from GTP, which is catalyzed by a zinc-dependent enzyme FolEIA or its metal-cambialistic paralog FolEIB . Consequently, low zinc lowers folate levels, causing AICAR accumulation and ZTP formation. In addition to the riboswitch, ZTP activates the zinc chaperone ZagA of the COG0523 protein family, which efficiently allocate zinc to zinc-dependent enzymes such as FolEIA .

Distribution, Geochemical Speciation, and Bioavailable Potencies of Cadmium, Copper, Lead, and Zinc in Sediments from Urban Coastal Environment in Osaka Bay, Japan

Due to proximity to the urban and industrial areas, coastal environments of the Osaka Bay have been continuously polluted with the human activities. Coastal sediments are known as large pool of contaminants including heavy metals. The Osaka Bay is no exception. However, recent information regarding the distributions, geochemical speciations, and risk evaluations of metals is limited for coastal sediments in the Bay. Therefore, we investigated the distributions, geochemical speciations, bioavailabilities, and conducted risk evaluations of the heavy metals, such as cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn) in sediments collected from 25 sites of the urban coastal environment of Osaka Bay, Japan. We observed high concentrations of Zn (76–967 mg/kg dry weight; DW) followed by Cu (not detected; ND-399 mg/kg DW), Pb (ND-73 mg/kg DW), and Cd (0.2–2.9 mg/kg DW). A considerable fraction of Cd was exchangeable (ND-0.4 mg/kg DW) and carbonate-bound (0.03–0.4 mg/kg DW). Cu occurred predominantly in the organic material-bound fraction (ND-348 mg/kg DW). Both Pb and Zn occurred predominantly in the Fe-Mn oxide fraction, with concentration ranges of ND-41 mg/kg DW and 24–277 mg/kg DW, respectively. Comparison with the effect range low (ERL) and effect range median (ERM) revealed that Cd, Cu, and Zn contribute potential biological toxicities to the sediments of Osaka Bay. High bioavailable concentrations of Cd and Zn may have ecotoxicological significance, because these metals are potentially highly available, especially to the benthic organisms.

System-level analysis of the generation and distribution for Pb, Cu, and Ag in the process network of zinc hydrometallurgy: Implications for sustainability

Heavy metals could serve as both pollutants and resources. To better understand the cleaner production potential of material flow control for simultaneous pollution reduction and resource conservation at source in zinc hydrometallurgy system, the generation and distribution of the Pb, Cu, and Ag in the process network of a typical zinc hydrometallurgy plant were investigated in this study. Four kinds of hazardous wastes with a total dry weight of 942 kg/tZn were identified as the major system outputs for Pb (12.08 kg/tZn), Cu (5.63 kg/tZn), and Ag (70.5 g/tZn). More than 85% of the target substances were accumulated in the leaching and purification subsystem, which determined the final proportion of the substances in the system outputs. The unsatisfactory distribution of the substances in the present process network contributes 0%, 45.9% and 27.5% of final resource wastage or pollution for Pb, Cu, and Ag of the generated wastes, corresponding to 0, 0.53 kg/tZn, and 13 g/tZn, respectively. Presently the Pb wastage or generation of Pb pollution was mainly due to the lack of recovery process. However, the potential to optimize the flow partitioning for Cu is relatively high. In summary, optimization of the process distribution might slightly increase the total recovery rate of the substances, but could significantly reduce the environmental risk of the disposed wastes generated in the zinc hydrometallurgy system. These results will be helpful to improve the understanding of the mechanisms for heavy metal pollution generation and provide further insight in the control of pollution and resource in process industries, such as nonferrous metals industry.

A retrospective mixed-methods evaluation of a national ORS and zinc scale-up program in Uganda between 2011 and 2016.

BackgroundIn Uganda, diarrhoea was the third leading cause of mortality among children under the age of five in 2010. To address this issue, the Ministry of Health (MOH) formed a national Diarrhoea and Pneumonia Coordination Committee (DPCC) in 2011. One of the objectives of the DPCC for reducing diarrhoea mortality was to increase the use of oral rehydration salts (ORS) and zinc. This study aimed to describe and evaluate efforts by the DPCC to increase ORS and zinc coverage.MethodsWe conducted a retrospective mixed-methods evaluation to describe the activities conducted under the DPCC and evaluate the extent to which the committee’s goal of increasing ORS and zinc use was achieved. We conducted secondary analysis using Uganda’s Demographic and Health Survey from 2011 and 2016, analyzed cross-sectional private medicine outlet surveys from 2014 and 2016, analyzed ORS and zinc distribution data from the Uganda National Medical Stores, and reviewed program documents from DPCC partners.ResultsNationally, the proportion of children under five with diarrhoea treated with ORS and zinc increased from 1% (95% confidence interval (CI) = 1%, 2%) in 2011 to 30% (95% CI = 27%, 32%) in 2016. Among private medicine outlets, the adjusted odds of having any zinc in-stock was 1.5 (95% CI = 1.14, 1.97) times higher in 2016 than in 2014, and the retail price for a complete treatment (2 ORS sachets and 10 zinc tablets) declined by $0.19 (95% CI = -0.31, -0.06), or 14%.ConclusionsUse of combined ORS and zinc for treatment of diarrhoea in children under five significantly increased in Uganda during the program period. The range of activities conducted by the various members of the DPCC likely contributed to the increase in the use of combined ORS and zinc.

The role of ZIP proteins in zinc assimilation and distribution in plants: current challenges

Soils with mineral deficiencies lead to nutritional imbalance in crops worldwide. Zinc (Zn) is a micronutrient that is fundamental for plant growth and development, being essential for the proper functioning of a range of enzymes and transcription factors. Zn transporters tightly regulate Zn homeostasis. Plants contain a large number of Zn-responsive genes that are specifically expressed under Zn deficiency to ensure the coordination of assimilatory pathways and meet the physiological requirements. This review brings together a range of studies that have been undertaken to investigate the effects of Zn status on the regulatory mechanisms involved in plant mineral nutrition. The ZIP (ZRT, IRT-like Protein) family is especially implicated in Zn transport and in the maintenance of cellular Zn homeostasis. Regulation of expression in relation to plant tissue, mineral concentration, and species has been determined for several ZIP family members. In the omic era, genomic and proteomic approaches have facilitated a rapid increase in our understanding of the roles of ZIP family members and their regulation, though significant knowledge gaps remain. A comprehensive understanding of ZIP proteins could lead to many potential molecular applications to improve crop management and food quality.

Revealing the internal organization of a Middle Bronze Age fortified settlement in Kakucs-Turján through geoarchaeological means: Magnetometric survey and sedimentological verification of a housing structure

Kakucs – Turján is a multi – layered fortified settlement from the Middle Bronze Age located in Central Hungary. The site was subjected to a non – invasive prospection using the magnetometry method. The magnetic anomalies provided insight into the horizontal plan of the site, revealing a tri-partite structure encircled and divided internally by ditches. In one of the so-defined zones, an agglomeration of a house – like anomalies were detected indicating the location of the housing area. One of these features was subjected to archaeological excavations which revealed the remains of two houses built on top of each other (tell – like deposition). In addition to excavations, sedimentological and geochemical sampling provided data on the functional aspects of the house. The spatial distribution of chemical elements and grain – size parameters showed that the house witnessed heavy anthropogenic activity. The distribution of phosphorous, copper and zinc indicated that a large part of activities could have taken place outside of the house, in the area where a suspected entrance was registered during the excavations. Geoarchaeological analysis at Kakucs – Turján thus resulted in a delimitation of the site's internal organization and a clarification of one of the house's chronology and functionality.

Hypothyroidism-related zinc deficiency leads to suppression of T lymphocyte activity.

Hypothyroidism has been shown to induce immunosuppression and both the thyroid status and immunity are affected by zinc deficiency. However, the impact of hypothyroidism on zinc metabolism and its possible relationship with the immune status has not yet been deeply explored. Here, our aim was to study whether hypothyroidism may alter zinc metabolism and thus lead to the impairment of T lymphocyte activity. Variations in the distribution of zinc in the body were evaluated in PTU-treated hypothyroid mice. The effects of hypothyroidism and zinc deficiency were studied on T lymphocyte proliferation after stimulation both in vitro and in vivo. For in vitro assays, thyroid hormone-free or zinc chelator (TPEN or DTPA)-supplemented media were used. For in vivo assays, lymphocyte activity was evaluated in cells from hypothyroid, T3-treated, and zinc-supplemented mice. Hypothyroid mice showed lower levels of zinc in femur and lymph nodes than controls. T3 and zinc supplementation reversed these effects. In vitro, both thyroid hormone and zinc deficiency led to a decreased response to mitogen stimulation. However, only zinc deficiency was able to induce lymphocyte apoptosis. Mitogen-stimulated T cells from hypothyroid mice showed impaired proliferation, accompanied by decreased activation of PKC and lower levels of p-ERK, effects that were reversed by T3 replacement or zinc supplementation. Our results show an important role of zinc deficiency in hypothyroid-mediated T-cell suppression and suggest the importance of evaluating zinc levels and restoring them when necessary to maintain an efficient immune response in hypothyroid patients.

Geochemical Distribution of Copper and Zinc in the Aquatic Sediment of Nyolo Spring Water at Karangploso Malang East Java

Aquatic sediment has a role for heavy metals sink. Understanding the geochemical fractions of heavy metals in the aquatic sediment can predict the mobility and reactivity of heavy metals fractions that can induce environmental problems. The aim of this study was to determine the distribution of geochemical fractions of copper and zinc in aquatic sediment of Nyolo spring. Sediments samples were taken from five locations along the spring. Geochemical fractions of copper and zinc were extracted using BCR (Community Bureau of Reference) sequential extraction method. The concentration of these metals in each extract was analyzed using AAS. The result showed that overall the sediment consisted of zinc at a higher concentration than copper. Amongst the geochemical fractions, copper and zinc were found dominantly at an oxidizable fraction. As the first fraction, Zn was more bioavailable than copper for biological uptake. Furthermore, based on the Risk Assessment Code (RAC) value, the aquatic sediment of Nyolo Spring was low risk to the Zn and Cu contaminations at most sites, except for Zn in Site III showed a medium risk. This metals fraction will potentially available for organism uptake with the changing of pH sediment or overlying water

Plant diversity and profile distribution of some available micronutrients in selected soils of Kano State, Nigeria

Availability of micronutrients in the right amount and proportion is vital for optimum nutrients utilization by diversity of plants. However, the current fertilizer recommendation for plants in Northern Nigeria is only for macronutrients and continuous application of one or two macronutrients may deplete the soil reserve of other nutrients; micronutrients inclusive, due to nutrients antagonism and consequently, reduce plant yield. For these reasons, this study was conducted to assess the profile distribution of zinc, copper, iron and manganese in selected soils of Kano state, Nigeria. Thirteen profile pits were sunk across thirteen (13) local government areas of Kano state. A total of (39) thirty nine composite samples were collected according to the pedogenic horizons at the different locations. In addition to the determination of other physical and chemical properties, available micronutrients; Cu, Fe, Zn and Mn were extracted with 0.1N HCl and the concentration of nutrients measured with atomic absorption spectrophotometer (AAS). Data obtained were subjected to Generalized Linear Model (GLM) procedure of Statistical Analysis Software (SAS) laid down in a randomized complete block design (RCBD). Significantly different means were then separated using Duncan multiple range test. Results obtained revealed that although Fe and Mn contents were adequate for crop production, Zn and Cu values ranges from 0.79 to 1.14 mg kg -1 and 0.76 to 1.11 mg kg - respectively and were rated as inadequate in all the soils of the study area as such, supplementary application of these micronutrients could be beneficial for plant diversity development. Similarly, addition of organic residues as well as including Cu and Zn in fertilizer blends to be used in soils of the study area is necessary to improve plant diversity development. However, result of plant diversity is indicated with the Sahel Savanna having1,086 species, Sudan Savanna 1,116 species and 1,264 species in the Northern Guinea Savanna respectively. Keywords: Distribution, Kano state, Micronutrients, Plant diversity, Soil profile

The The influence of high doses of α-tocopherol on the content of selected trace elements in the liver of developing chicken embryos in experimentally induced 2,3,7,8-tetrachlorodibenzo-p-dioxin intoxication.

A chicken embryo develops in ovo without access to a constant circulating maternal nutrient supply, and therefore all necessary nutrients are initially stored in the yolk, and with progressive development are transferred to the liver, where they are taken up in response to various needs. Fluctuations in hepatic trace elements correlate with their mobilization from egg stores. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) intoxication causes liver damage by production of free radicals, while α-tocopherol is a well-known antioxidant and may play a protective role. In the experiment presented here, a solution containing only TCDD, TCDD and α-tocopherol, as well as α-tocopherol exclusively, was administrated into the yolk sac. The iron, zinc, copper and magnesium distribution was evaluated using histological and chemical methods. It has been found that α-tocopherol has no influence on magnesium and zinc content in the liver. The observed increase in iron content may be caused by antagonistic action of iron and α-tocopherol. On the other hand, synergistic action of α-tocopherol and TCDD has been noted with respect to the copper content.

Spatial distribution of zinc in the topsoil of four vegetated infiltration swales treating zinc roof runoff

Since stormwater runoff from zinc roofs is polluted with high concentrations of zinc (Zn), runoff treatment is recommended in order to avoid harmful influences to the ecosystem. For the retention of Zn, vegetated infiltration swales with a topsoil layer are often used as decentralized Sustainable Urban Drainage Systems (SUDS). The aim of this study was to assess the risks of groundwater contamination due to infiltration of stormwater runoff of a Zn roof using infiltration swales. The spatial horizontal and vertical distribution of Zn content in four 15 year old vegetated infiltration swales at a zinc roof was analyzed and evaluated. High Zn contents (up to 27.9 g/kg dry mass) have been measured only for spatially limited areas at the inflow zones of each infiltration swale. Zn content decreased significantly with increasing distance from inflow and with increasing topsoil depth. Because the topsoil is still contaminated in deeper layers and because the soil's sorption potential is locally exceeded, the risk of groundwater contamination was expected to be high. Possible optimization of the hydraulic functioning and regular maintenance of the swales is recommended as well as a regular topsoil exchange of highly polluted areas.

Correlation between microstructure and corrosion behaviour of Bi-Zn solder alloys

ABSTRACTBi-Zn solder alloys with different Zn contents (1.5, 2.7 and 5wt-%) were prepared by casting and the correlation between the microstructure and corrosion behaviour by mean of direct current electrochemical tests was studied. The surface analysis of the hypoeutectic Bi-Zn alloy samples revealed the presence of needle-like ZnO and very small agglomerated spherical particles. By contrast, eutectic alloy presented the formation of a uniform and compact film of ZnO, which is related to the better distribution of Zinc in the Bi-rich matrix. Despite the increase in Zn content compared to the hypoeutectic alloy, the corrosion rate showed similar values regardless of its content in the alloy. The Bi-5wt-% Zn alloy presented the highest limiting current density, and consequently, the highest degree of corrosion of the studied alloys. The pro-eutectic phase consisting of large and thick Zn fibres is preferentially dissolved, promoting a selective attack that penetrates inside the sample.

Novel CBWD Gene Products Augment Mammalian Zinc Homeostasis

The CBWD genes (coding for COBW domain‐containing proteins) was previously identified through an in silico search of the human genome for the presence of a zinc‐responsive element known as Zinc Transcriptional Regulatory Element (ZTRE)1. The human CBWD gene family consist of six isoforms with different chromosomal and cytogenetic locations and exhibit a remarkable nucleotide and amino acid sequence conservation. The prokaryotic homologues of CBWD proteins belonging to the GOG0523 family of proteins have been reported to have roles in zinc homeostasis2, however, no known role has yet been documented for the mammalian types. The discovery that the zinc‐sensitive element (ZTRE) occurred in multiple copies of the CBWD genes was intriguing and triggered further investigations into a likely role for this gene family in mammalian cellular zinc handling and/or trafficking. Moreover, we reported a protein that acts at the ZTRE site to mediate regulation of zinc homeostatic genes and found CBWD genes to be a prominent feature3. Using Caco‐2 cells as in vitro model of human enterocytes, we demonstrate the ability of CBWD genes to respond to changes in zinc content at both transcriptional and post‐transcriptional levels evidenced by decreased transcript and overexpressed protein abundance in response to increased extracellular zinc concentration. We also show that increased expression of CBWD protein through a transgene extended cellular tolerance to extreme windows of zinc availability, demonstrating the potential of the human CBWD gene products to augment cellular zinc buffering. This potential buffering ability of CBWD gene products may be effected through cellular zinc redistribution evidenced by a less punctate zinc distribution in cells made to overexpress CBWD protein compared to control cells. Furthermore, overexpression of COBW protein attenuated the responsiveness of a zinc‐sensitive metallothionein promoter, indicating an action consistent with a role in zinc trafficking or buffering. These findings give plausible evidence in support of the involvement of the mammalian CBWD gene products in cellular zinc homeostasis.Support or Funding InformationThis work was supported by the Nigerian Tertiary Education Trust Fund through Benue State University, Makurdi, Benue State NigeriaThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Fatigue life of micro-arc oxidation coated AA2024-T3 and AA7075-T6 alloys

Two types of aluminum (Al) alloys, namely 2024-T3 and 7075-T6, were treated by micro-arc oxidation (MAO). Microstructure of as-fabricated ceramic coatings was investigated. Furthermore, the effect of MAO time on fatigue life of the coated samples with thin coating was systematically explored. Morphologies of the coating, second phase particles, and distribution of copper (Cu) and Zinc (Zn) in the coating were observed by scanning electron microscopy, confocal laser scanning microscopy, and energy dispersive spectrometry. Residual stress and phase compositions were analyzed by X-ray diffraction. More Cu in 2024-T3 Al alloy promoted formation of the coating; however, surface porosity of the coating was high. Residual stress induced in the coating deposited on AA2024 was compressive in nature. In contrast, the residual stress in the coating prepared on AA7075 was tensile due to the high content of Zn in the substrate. The results of fatigue test showed that fatigue life of the coated AA2024 increased; however, the MAO treatment was detrimental to fatigue performance of the AA7075 compared to uncoated samples. With prolonging oxidation time, the fatigue life of the coated samples first increased and then decreased. The changes of fatigue life were attributed to the residual stress, coating defects including micro-pores and micro-cracks, and second phase particles in the Al alloy substrate.

Trace mineral source influences ruminal distribution of copper and zinc and their binding strength to ruminal digesta1,2,3.

Eight crossbred steers (BW 719.0 ± 65.0 kg) with ruminal and duodenal cannulae were used to examine the effect of trace mineral (TM) source on digestibility; ruminal and duodenal solubility of Cu, Zn, and Mn; and in vitro release of Cu, Zn, and Mn from the solid fraction of ruminal digesta. Experiment 1 determined the effect of TM source on DM and NDF digestibility in steers fed a corn silage and steam-flaked corn-based diet. Treatments consisted of 10 mg Cu, 20 mg Mn, and 30 mg Zn/kg DM from either sulfate TM (STM) or hydroxy TM (HTM) sources. Following a 14-d adaptation period, total fecal output was collected for 5 d. Dry matter digestibility was not affected by treatment, but NDF digestibility tended (P < 0.09) to be greater in HTM vs. STM supplemented steers. In Exp. 2, steers were fed a diet without supplemental Cu, Zn, or Mn for 19 d. Steers were then administrated a pulse dose of STM or HTM (2× the National Research Council requirements for Cu, Mn, and Zn) via the rumen fistula. Ruminal and duodenal samples were obtained at 2-h intervals starting at -4 and ending at 24 h relative to dosing. Ruminal soluble Cu and Zn concentrations were affected by treatment, time, and treatment × time. Soluble concentrations and percent soluble Cu and Zn in ruminal digesta increased (P < 0.05) above 0-h values for 10 h following dosing with STM, but not HTM. Concentrations of Cu and Zn in ruminal solid digesta were also affected by treatment, time, and treatment × time. Steers dosed with STM had greater (P < 0.05) solid digesta Cu concentrations at 2 and 4 h but lesser (P < 0.05) concentrations from 6 to 20 h post-dosing than those receiving HTM. Ruminal solid digesta Zn concentrations were greater (P < 0.05) in HTM vs. STM-dosed steers from 6 through 24 h post-dosing. Distribution of Mn in ruminal digesta was affected by TM source, but to a lesser extent than Zn and Cu. Duodenal soluble TM concentrations were variable and not affected by treatment. Binding strength of TM to ruminal solid digesta was estimated at 0, 6, and 12 h post-dosing using dialysis against chelating agents. The percentage of Cu and Zn released from ruminal solid digesta by dialysis against Tris-EDTA was greater (P < 0.05) at 12 h post-dosing from steers receiving HTM vs. STM. Results indicate that Cu and Zn from HTM have low solubility in the rumen and appear to be less tightly bound to ruminal solid digesta than Cu and Zn from STM.

BÜYÜKÇEKMECE GÖLÜ HAVZASINDA TOPRAK KİRLİLİĞİNİN COĞRAFİ BİLGİ SİSTEMLERİ İLE İNCELENMESİ

Heavy metals, emitted from many anthropogenic sources, are the most common pollutants in the soil as a result of rapid urbanization. Heavy metal pollution in heavily urbanized areas are one of the important environmental problems due to their potential impacts on human health. Determination of the soil pollution potential is of great importance to utilization and protection of soil resources. Therefore, in this study, it is aimed to determine the spatial distribution of copper (Cu), nickel (Ni), cadmium (Cd) and zinc (Zn) heavy metals and the sources of pollution in the surface soils of Büyükçekmece Basin. 40 soil samples with pre-determined coordinates by systematic random grid sampling method were collected from the study area in February 2016. Geographic Information Systems and spatial analysis, used most frequently in determining soil contamination and spatial distribution in recent years, were used to determine the spatial distribution of heavy metals being studied. As a result of the study, it was observed that the concentration values of copper (Cu), nickel (Ni), cadmium (Cd) and zinc (Zn), were high in the overall study area. Hazardous points in terms of contaminants had been identified throughout the study area. However, the highest values were generally observed around the lake in the south of the study area. For this reason, the study area was considered as highly risky in terms of ecological risks. It was concluded that the source of Cu, Ni, Cd and Zn pollution found in Büyükçekmece Basin soil was closely associated with industrial establishments and settlements.

Distributions of cadmium, zinc, and polyphenols in Gamblea innovans

Gamblea innovans is a Cd- and Zn-accumulating deciduous tree widely distributed in the secondary forests of Japan. We aimed to understand the characteristics of Cd and Zn accumulation in G. innovans in order to effectively utilize the species for phytoremediation. To accomplish that, we studied the relationship between secondary metabolite concentrations and the accumulation and distributions of Cd and Zn in G. innovans leaves and basal stems using micro-X ray fluorescence (µ-XRF). Our results showed a negative correlation between Zn leaf concentrations and polyphenol/2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. This finding might be related to stress or the manifestation of a mechanism for tolerance to Cd and Zn accumulation. In addition, we observed that Cd accumulated primarily in the apoplastic region of surface tissues such as bark and the epidermis of leaves, whereas Zn accumulated in both apoplastic and symplastic regions. Thus, it might be possible that G. innovans can distinguish between Cd and Zn and control their translocation.

Investigation of calcium and zinc distribution in rabbit patella-patellar tendon interface using synchrotron radiation micro X-ray fluorescence technique

Objective The unique distributions and maps of calcium and zinc at the regions of interest in patella-patellar tendon interface (PPTI) were detected by synchrotron radiation micro X-ray fluorescence (SR-μXRF). Methods Healthy New Zealand rabbits were used in this experiment. Five harvested PPTI samples were cut along the sagittal plane of the PPTI by a microtome. Sections of PPTI were then scanned by SR-μXRF at BL15U1 of shanghai synchrotron radiation facility (SSRF) in China. Then the samples were used for histological staining with hematoxylin and eosin (HE) and Van-Gieson. Results Histological staining showed that the thickness of calcified fibrocartilage in PPTI was (163.00±42.00) μm; The distributions and characterization of calcium and zinc of PPTI were successfully obtained via the SR-μXRF. The maximum calcium content [93 853 cps, (28.00±9.05) times of that of patellar tendon] was found in the transitional zone of calcified fibrocartilage region and the patella. A significant accumulation of zinc [10 100 cps, (3.20±0.65) times of that of patellar tendon] was exhibited in the transition area of tidemark. The maximum content of zinc was (8.70±3.20) times of that of calcium. The distribution distance between the maximum content of calcium and zinc was (135.00±16.00) μm, which was consistent with histological staining (r2=0.935). Conclusion SR-μXRF served as a high-precision and high-resolution instrument to qualitatively assess the distributions of calcium and zinc in the PPTI, which provides a new insight for the study of bone tendon interface repair. Key words: Synchrotron radiation-based micro X-ray fluorescence analysis; Calcium; Zinc; Bone tendon interface

Changes in copper, zinc and cadmium distributions in the liver of Formosan squirrels with characteristic high copper accumulation.

We discovered previously that Formosan squirrels (Callosciurus erythraeus) accumulate copper (Cu) in their livers at levels averaging 1700 μg per dry g (approximately 420 μg per wet g). In the current study, we investigated the relationship between Cu accumulation and hepatic injury, and we determined the distribution and chemical form of Cu in the liver supernatant. In particular, we explored the role of metallothionein in the liver supernatant. We observed no significant differences in hepatic Cu concentration between squirrels that showed pathological changes in the liver and those that did not. Serum alanine aminotransferase activity did not increase with increasing hepatic Cu concentration. These results suggest that abnormal Cu accumulation in the livers of Formosan squirrels does not induce severe hepatic injury. We found that 26.7% of the Cu in the liver was distributed to the supernatant, and only 11.0% of the Cu in the liver was bound to metallothionein, suggesting that metallothionein in the hepatic supernatant does not contribute to detoxification of excess Cu in Formosan squirrels.

Y–Zn–Al system at 670 K

Interaction of the components in the ternary Y–Zn–Al system at the temperature 670 K has been studied by means of the X-ray phase and structure analyses. Samples for investigation have been prepared by double sintering of previously pressed into pellets mixtures of powders of pure components. Pellets were sealed into evacuated quarts tubes and then heat-treated in the muffle furnace. Existence of the earlier known ternary aluminides, namely Y 3 Zn 3.25 Al 7.75 (space group Immm , La 3 Al 11 –type of structure), and YZnAl (space group P 6 3 / mmc , CaIn 2 –type of structure) has been confirmed and new ternary compound Y 4 Zn 22,34 Al 9,66 Zn 0,22 (Yb 8 Cu 16 Al 49 –type of structure, space group I 4/ mmm ) has been studied. Limit compositions of the solid solutions on the base of several Y–Al and Y–Zn binary compounds have been established: Y(Zn 0.90 Al 0.10 ) 12 (ThMn 12 –type of structure, space group I 4/ mmm , a = 0.88789(2), c = 0.52381(2) nm), Y 2 (Zn 0.95 Al 0.05 ) 17 (Th 2 Zn 17 –type of structure, space group R -3 m , a = 0.90006(4), c = 1.31388(6) nm), YZn 0.76 Al 0.24 (CsCl–type of structure, space group Pm -3 m , a = 0.35645(2) nm), Y(Al 0.93 Zn 0.07 ) 3 (BaPb 3 –type of structure, space group R -3 m , a = 0.61929(2), c = 2.1115(1) nm), and Y(Al 0.88 Zn 0.12 ) 2 (MgCu 2 –type of structure, space group Fd -3 m , a = 0.78486(2) nm). All solid solutions are formed due to the substitution of zinc and aluminum atoms in the crystallographic positions of the respective space groups. Other binary compounds don’t dissolve any significant amount of the third component. Ternary compounds with the structures of CaIn 2 and La 3 Al 11 –types have large homogeneity ranges, and their compositions can be described by formulas: YZn 0.90-1.05 Al 1.10-0.95 ( a = 0.4472(1)–0.4495(1), c = 0.7127(1)–0.7138(1) nm) and Y 3 Zn 3.15-4.10 Al 7.85-6.90 ( a = 0.4219(1)–0.4231(1), b = 1.2423(1)–1.2471(2), c = 0.9901(2)–0.9989(2) nm). However, the ternary compound Y 4 Zn 22 . 7 Al 9 . 5 Zn 0 . 2 , despite the statistical distribution of zinc and aluminum atoms in the structure, does not form noticeable homogeneity range. Crystal structure of the compounds YZn 1.02 Al 0.98 (CaIn 2 -type of structure, space group P 6 3 / mmc , Pearson’s symbol h P6, refined lattice parameters a = 0.44923(5), c = 0.7136(1) nm, R I = 0.072, R P = 0.126) and Y 4 Zn 22,34 Al 9,66 Zn 0,22 (Yb 8 Cu 16 Al 49 -type of structure, space group I 4/ mmm , Pearson’s symbol t I72,4, a = 0,86182(2), c = 1,65054(3) nm, R I = 0,078, R P = 0,127) has been studied from powder X-ray diffraction data. Isothermal section of the ternary Y–Zn–Al system has been constructed at 670 K and concentration range up to 70 at. % of yttrium. Keywords: intermetallic compound, crystal structure, phase equilibria.