Hair cortisol reflects socio-economic factors and hair zinc in preschoolers

This study examined the relationship between children's hair cortisol and socioeconomic status of the family, as measured by parental education and income. Low family socioeconomic status has traditionally been considered a long-term environmental stressor. Measurement of hair cortisol provides an integrated index of cumulative stress exposure across an extended period of time. The present study is the first to examine the relationship between hair cortisol and parental education as well as parental income in a representative sample of preschoolers. Data on hair cortisol, family income, and parental education were collected for a representative sample of 339 children (Mean age=4.6 years; SD=.5 years) from across 23 neighbourhoods of the city of Vancouver, Canada. As maternal education was shown previously to be associated with hair zinc level, hair zinc measurements were included as well in order to explore potential relationships between hair zinc and hair cortisol. The relationship between hair cortisol and parental education was examined using hierarchical regression, with hair zinc, gender, age, and single parenthood included as covariates. Maternal and paternal education both were correlated significantly with hair cortisol (r=-0.18; p=.001). The relationship remained statistically significant even after controlling for all demographic covariates as well as for hair zinc and after taking the neighbourhood-level clustering of the data into account. Parental income, on the other hand, was not related significantly to children's hair cortisol. This study provides evidence that lower maternal and paternal education are associated with higher hair cortisol levels. As hair cortisol provides an integrated index of cortisol exposure over an extended time period, these findings suggest a possibly stable influence of SES on the function of the hypothalamic-pituitary-adrenal (HPA) axis. Cumulative exposure to cortisol during early childhood may be greater in children from low socio-economic backgrounds, possibly through increased exposure to environmental stressors.

The complex effects of the slow-releasing hydrogen sulfide donor GYY4137 in a model of acute joint inflammation and in human cartilage cells

The role of hydrogen sulfide (H2 S) in inflammation remains unclear with both pro- and anti-inflammatory actions of this gas described. We have now assessed the effect of GYY4137 (a slow-releasing H2 S donor) on lipopolysaccharide (LPS)-evoked release of inflammatory mediators from human synoviocytes (HFLS) and articular chondrocytes (HAC) in vitro. We have also examined the effect of GYY4137 in a complete Freund's adjuvant (CFA) model of acute joint inflammation in the mouse. GYY4137 (0.1-0.5 mM) decreased LPS-induced production of nitrite (NO2 (-) ), PGE2 , TNF-a and IL-6 from HFLS and HAC, reduced the levels and catalytic activity of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) and reduced LPS-induced NF-?B activation in vitro. Using recombinant human enzymes, GYY4137 inhibited the activity of COX-2, iNOS and TNF-a converting enzyme (TACE). In the CFA-treated mouse, GYY4137 (50 mg/kg, i.p.) injected 1 hr prior to CFA increased knee joint swelling while an anti-inflammatory effect, as demonstrated by reduced synovial fluid myeloperoxidase (MPO) and N-acetyl-ß-D-glucosaminidase (NAG) activity and decreased TNF-a, IL-1ß, IL-6 and IL-8 concentration, was apparent when GYY4137 was injected 6 hrs after CFA. GYY4137 was also anti-inflammatory when given 18 hrs after CFA. Thus, although GYY4137 consistently reduced the generation of pro-inflammatory mediators from human joint cells in vitro, its effect on acute joint inflammation in vivo depended on the timing of administration.

The electrochemical reduction of 1-bromo-4-nitrobenzene at zinc electrodes in a room-temperature ionic liquid: a facile route for the formation of arylzinc compounds

The electrochemical reduction of 1-bromo-4-nitrobenzene (p-BrC₆H₄NO₂) at zinc microelectrodes in the [C(₄)mPyrr][NTf₂] ionic liquid was investigated via cyclic voltammetry. The reduction was found to occur via an EC type mechanism, where p-BrC₆H₄NO₂ is first reduced by one electron, quasi-reversibly, to yield the corresponding radical anion. The radical anions then react with the Zn electrode to form arylzinc products. Introduction of carbon dioxide into the system led to reaction with the arylzinc species, fingerprinting the formation of the latter. This method thus demonstrates a proof-of-concept of the formation of functionalised arylzinc species.

Age-Associated Changes of Brain Copper, Iron, and Zinc in Alzheimer's Disease and Dementia with Lewy Bodies

Disease-, age-, and gender-associated changes in brain copper, iron, and zinc were assessed in postmortem neocortical tissue (Brodmann area 7) from patients with moderate Alzheimer's disease (AD) (n = 14), severe AD (n = 28), dementia with Lewy bodies (n = 15), and normal age-matched control subjects (n = 26). Copper was lower (20%; p < 0.001) and iron higher (10–16%; p < 0.001) in severe AD compared with controls. Intriguingly significant Group*Age interactions were observed for both copper and iron, suggesting gradual age-associated decline of these metals in healthy non-cognitively impaired individuals. Zinc was unaffected in any disease pathologies and no age-associated changes were apparent. Age-associated changes in brain elements warrant further investigation.

Two-dimensional images of dissolved sulfide and metals in anoxic sediments by a novel diffusive gradients in thin film probe and optical scanning techniques

A novel diffusive gradients in thin film probe developed comprises diffusive gel layer of silver iodide (AgI) and a back-up Microchelex resin gel layer. 2D high-resolution images of sulfide and trace metals were determined respectively on the AgI gel by densitometric analysis and on the Microchelex resin layer with laser-ablation-inductively-coupled plasma mass spectrometry (LA-ICP-MS).We investigated the validity of the analytical procedures used for the determination of sulfide and trace metals. We found low relative standard deviations on replicate measurements, linear trace-metal calibration curves between the LA-ICP-MS signal and the true trace-metal concentration in the resin gel, and a good agreement of the sulfide results obtained with the AgI resin gel and with other analytical methods. The method was applied on anoxic sediment pore waters in an estuarine and marine system. Simultaneous remobilization of sulfide and trace metals was observed in the marine sediment.

Ionic liquids for efficient hydrogen sulfide and thiol scavenging

Functionalised pyridinium and ammonium ionic liquids bearing a Michael acceptor are shown to scavenge H₂S gas and various thiols, in most cases, without the aid of any added bases. Utilising the effective non-volatility of ionic liquids and ‘tagging’ malodourous substances to an ionic matrix renders them odourless.

Zinc selenide nano- and microspheres via microwave-assisted ionothermal synthesis

Zinc selenide nanospheres were prepared from a diphenyl diselenide precursor and a range of chloro- and bromozincate(II) ionic liquids via a microwave-assisted ionothermal route; this is the first report on the use of microwave irradiation in combination with ionic liquids to prepare this material. The method is a time-efficient and a facile one-pot reaction to produce zinc(II) selenide nanomaterials. The product formation in the ionic liquids has been monitored using Raman spectroscopy. The products have been characterised using PXRD, SEM, EDX, photoluminescence and UV-VIS spectroscopy. Advantages of this new route, such as ease of solubilisation of all reactants into one phase at high concentration, the negligible vapour pressure irrespective of the reaction temperature, very fast reaction times, ease of potential scale-up and reproducibility are discussed.

The effect of variability in the powder/liquid ratio on the strength of zinc phosphate cement

Aim. To investigate (a) variability in powder/liquid proportioning and (b) effect of variability on diametral tensile strength (DTS), in a zinc phosphate cement. Statistical analyses (α = 0.05) were by Student's t-test in the case of powder/liquid ratio and one-way ANOVA and Tukey HSD for pair-wise comparisons of mean DTS. The Null hypotheses were that (a) the powder-liquid mixing ratios would not differ from the manufacturer's recommended ratio (b) DTS of the set cement samples using the extreme powder/liquid ratios would not differ from those made using the recommended ratio. 

Methodology. 34 dental students dispensed the components according to the manufacturer's instructions. The maximum and minimum powder/liquid ratios, together with the manufacturer's recommended ratio, were used to prepare samples for DTS testing. 

Results. Powder/liquid ratios ranged from 2.386 to 1.018. The mean ratio (1.644) was not significantly different from the recommended value of 1.718 (P = 0.189). DTS values for the maximum and minimum ratios were both significantly different from each other (P < 0.001) and from the mean value obtained from the recommended ratio (P < 0.001). 

Conclusions. Variability exists in powder/liquid ratio for hand dispensed zinc phosphate cement. This variability can affect the DTS of the set material.

Genome Wide Association Mapping of Grain Arsenic, Copper, Molybdenum and Zinc in Rice (Oryza sativa L.) Grown at Four International Field Sites

The mineral concentrations in cereals are important for human health, especially for individuals who consume a cereal subsistence diet. A number of elements, such as zinc, are required within the diet, while some elements are toxic to humans, for example arsenic. In this study we carry out genome-wide association (GWA) mapping of grain concentrations of arsenic, copper, molybdenum and zinc in brown rice using an established rice diversity panel of,300 accessions and 36.9 k single nucleotide polymorphisms (SNPs). The study was performed across five environments: one field site in Bangladesh, one in China and two in the US, with one of the US sites repeated over two years. GWA mapping on the whole dataset and on separate subpopulations of rice revealed a large number of loci significantly associated with variation in grain arsenic, copper, molybdenum and zinc. Seventeen of these loci were detected in data obtained from grain cultivated in more than one field location, and six co-localise with previously identified quantitative trait loci. Additionally, a number of candidate genes for the uptake or transport of these elements were located near significantly associated SNPs (within 200 kb, the estimated global linkage disequilibrium previously employed in this rice panel). This analysis highlights a number of genomic regions and candidate genes for further analysis as well as the challenges faced when mapping environmentally-variable traits in a highly genetically structured diversity panel.

A hydrogel based zinc(ii) sensor for use in fluorescent multi-well plate analysis

A polymeric hydrogel containing a photoinduced electron transfer (PET) based probe for Zn(ii) has been formulated into the wells of a 96-well plate. Upon addition of Zn(ii) ions to selected wells, the fluorescence of the gel was observed to increase in a concentration dependent manner in the 0.25-1.75 mM range. The millimolar binding constant observed for this probe is higher than that reported for other Zn(ii) probes in the literature and offers the possibility to determine the concentration of this ion in environments where the Zn(ii) concentration is high. The combination of the multi-well plate set-up with fluorescence detection offers the possibility of high-throughput screening using low sample volumes in a timely manner. To the best of our knowledge, this is the first reported example of a polymeric hydrogel sensor for zinc with capability for use in fluorescence multi-well plate assay.

Zinc Phosphate Cement: Variations in proportioning affects dimetral tensile strength

Objectives: To quantify variability in hand proportioning of zinc phosphate cement among a cohort of dental undergraduates and to determine the effect of any such variability on the diametral tensile strength (DTS) of the set cement. The null hypothesis was that such variability has no effect on DTS. 
Methods: Thirty-four operators dispensed a zinc phosphate cement [Fleck's® Cement] according to the manufacturers' instructions. The mass of powder and liquid dispensed was recorded. Cylindrical specimens (n = 2 x 34) of dimensions 6mm x 3mm were prepared using a stainless steel split mould. The maximum mass of powder and the minimum volume of liquid were used as one extreme ratio and the minimum mass of powder and the maximum volume of liquid used on the other extreme. The manufacturers' recommended ratio was also tested (n=34).The samples were left to set for one hour before being transferred into distilled water for 48 hours. Compression across a diameter was carried out using a universal testing machine, H10KS [Tinius Olsen], at a constant crosshead speed of 0.75 ±0.25 mm/min. Statistical analyses (α = 0.05) were by Student's t-test for the powder/liquid ratio and one-way ANOVA and Tukey HSD for for pair-wise comparisons of mean DTS. Tests were carried out for normality and constant variability. 
Results: The mean (range) amount of powder dispensed was 0.863g (0.531-1.216)g. The mean (range) amount of liquid dispensed was 0.341ml (0.265-0.394)ml. The manufacturer's recommended amounts were 0.8g of powder and 0.3ml of liquid. The mean powder/liquid ratio was not significantly different from the manufacturer's recommended value (p=0.64). Mean (SD) DTS were (MPa) max: 7.19(1.50), min: 2.65(1.01), manufacturer: 6.01(1.30). All pair-wise comparisons were significantly different (p<0.001). 
Conclusions: Variability exists in the hand proportioning powder and liquid components of zinc phosphate cement. This variability can affect the DTS of zinc phosphate cement.

Toxic effects of cadmium and zinc on ectomycorrhizal colonization of scots pine (Pinus sylvestris L.) from soil inoculum

Scots pine seedlings colonized by ectomycorrhizal (ECM) fungi from natural soil inoculum were exposed to a range of Cd or Zn concentrations to investigate the effects of metals on ECM fungi-Scots pine associations in a realistic soil environment. Experiments focused on the relationship between the sensitivity of ECM fungi and their host plants, the influence of metals on ECM community dynamics on Scots pine roots, and the effects of metal exposure on ECM colonization from soil-borne propagules. Ectomycorrhizal colonization was inhibited by Cd and Zn, with a decrease in the proportion of ECM-colonized root tips. Shoot and root biomass, total root length, and total root-tip density, however, were unaffected by Cd or Zn. A decrease in the diversity of ECM morphotypes also occurred, which could have a negative effect on tree vigor. Overall, colonization by ECM fungi was more sensitive than seedling growth to Cd and Zn, and this could have serious implications for successful tree establishment on metal-contaminated soils.

Orange Zinc Germanate with Metallic Ge-Ge Bonds as a Chromophore-Like Center for Visible-Light-Driven Water Splitting

The efficiency of solar-energy-conversion devices depends on the absorption region and intensity of the photon collectors. Organic chromophores, which have been widely stabilized on inorganic semiconductors for light trapping, are limited by the interface between the chromophore and semiconductor. Herein we report a novel orange zinc germanate (Zn-Ge-O) with a chromophore-like structure, by which the absorption region can be dramatically expanded. Structural characterizations and theoretical calculations together reveal that the origin of visible-light response can be attributed to the unusual metallic Ge-Ge bonds which act in a similar way to organic chromophores. Benefiting from the enhanced light harvest, the orange Zn-Ge-O demonstrates superior capacity for solar-driven hydrogen production.

A primer for the Environmental Impact Assessment of mining at seafloor massive sulfide deposits

Seafloor massive sulfides (SMS) contain commercially viable quantities of high grade ores, making them attractive prospect sites for marine mining. SMS deposits may also contain hydrothermal vent ecosystems populated by high conservation value vent-endemic species. Responsible environmental management of these resources is best achieved by the adoption of a precautionary approach. Part of this precautionary approach involves the Environmental Impact Assessment (EIA) of exploration and exploitative activities at SMS deposits. The VentBase 2012 workshop provided a forum for stakeholders and scientists to discuss issues surrounding SMS exploration and exploitation. This forum recognised the requirement for a primer which would relate concepts underpinning EIA at SMS deposits. The purpose of this primer is to inform policy makers about EIA at SMS deposits in order to aid management decisions. The primer offers a basic introduction to SMS deposits and their associated ecology, and the basic requirements for EIA at SMS deposits; including initial data and information scoping, environmental survey, and ecological risk assessment. © 2013 Elsevier Ltd.