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.

Contribution of sewage organic matter to the diet of the common limpet near the former outflow at Blackhead, Northern Ireland

Stable isotopes (δ13C, δ15N) have been used to document the utilisation of sewage effluent in coastal marine foodwebs in a number of studies (e.g. Rau et al. 1981; Risk et al. 2009; Rogers 1999; 2003). δ13C and, especially, δ15N showed clear differences in the diet of common limpets (Patella vulgata) collected in June 2010 near the untreated sewage outfall at Blackhead, Northern Ireland and a ‘clean’ site nearby. Because sewage contains a significant portion of fossil-fuel derived compounds (Law et al. 2013), 14C measurements enabled us to estimate the contribution of fossil carbon to the effluent and to the foodweb and hence of the level of sewage contamination. The effluent was found to contain 12.2 ± x % fossil carbon on the day sampled. The modern marine carbon endmember is enriched by the discharge from the Sellafield nuclear fuel reprocessing plant across the Irish Sea (c.f. Cook et al. 2004) so 14C analyses of samples from the ‘clean’ site were needed. We found that 38.5 ±x % of the diet of common limpets collected near the sewage was derived from fossil fuel. We plan to collect samples from the same two sites in June 2014 to establish whether the 2012 relocation of the outfall, with preliminary treated discharge farther out to sea has eliminated the contamination at Blackhead

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.

WHO guidelines for a healthy diet and mortality from cardiovascular disease in European and American elderly: the CHANCES project

BACKGROUND: Cardiovascular disease (CVD) represents a leading cause of mortality worldwide, especially in the elderly. Lowering the number of CVD deaths requires preventive strategies targeted on the elderly.

OBJECTIVE: The objective was to generate evidence on the association between WHO dietary recommendations and mortality from CVD, coronary artery disease (CAD), and stroke in the elderly aged ≥60 y.

DESIGN: We analyzed data from 10 prospective cohort studies from Europe and the United States comprising a total sample of 281,874 men and women free from chronic diseases at baseline. Components of the Healthy Diet Indicator (HDI) included saturated fatty acids, polyunsaturated fatty acids, mono- and disaccharides, protein, cholesterol, dietary fiber, and fruit and vegetables. Cohort-specific HRs adjusted for sex, education, smoking, physical activity, and energy and alcohol intakes were pooled by using a random-effects model.

RESULTS: During 3,322,768 person-years of follow-up, 12,492 people died of CVD. An increase of 10 HDI points (complete adherence to an additional WHO guideline) was, on average, not associated with CVD mortality (HR: 0.94; 95% CI: 0.86, 1.03), CAD mortality (HR: 0.99; 95% CI: 0.85, 1.14), or stroke mortality (HR: 0.95; 95% CI: 0.88, 1.03). However, after stratification of the data by geographic region, adherence to the HDI was associated with reduced CVD mortality in the southern European cohorts (HR: 0.87; 95% CI: 0.79, 0.96; I(2) = 0%) and in the US cohort (HR: 0.85; 95% CI: 0.83, 0.87; I(2) = not applicable).

CONCLUSION: Overall, greater adherence to the WHO dietary guidelines was not significantly associated with CVD mortality, but the results varied across regions. Clear inverse associations were observed in elderly populations in southern Europe and the United States.

Chronic PEGylated obestatin treatment prevents the onset of high fat diet-induced hypertension and endothelial dysfunction in the absence of metabolic actions

Background: Obestatin is a gastrointestinal peptide with established metabolic actions and emerging vascular effects which involve activation of NO signalling. The aim of this study was to investigate effects of a recently-characterised stable analogue, PEGylated obestatin (PEG-OB), in the setting of diet-induced obesity which is associated with both metabolic and vascular dysfunction. Methods: Male Sprague Dawley rats (6 weeks; n=8) were maintained on standard (SD) or high fat (HF) diet (60% fat) for 8 weeks with once-daily injection of either PEG-OB (50nmol/kg/day) or saline from 2 weeks. Results: HF feeding for 8 weeks resulted in marked body weight gain which was not affected by chronic PEG-OB treatment (HF saline, 175.0±12.2; HF PEG-OB, 190.4±6.4g; P=NS). Similarly, blood glucose, as indicated by HbA1c (HF saline, 6.30±0.15; HF PEG-OB, 6.13±0.36%; P=NS) and insulin tolerance (HF saline, 105.2±52.5; HF PEG-OB, 90.3±45.4mmol/L.min; P=NS), were unaltered by PEG-OB. Despite the apparent lack of metabolic effects, chronic PEG-OB treatment markedly attenuated development of HF-induced hypertension (HF saline, 146.5±4.9mmHg; HF PEG-OB, 123.0±9.7mmHg; P<0.01), assessed by tail-cuff plethysmography. Furthermore, organ bath pharmacology in isolated aortic rings, indicated that HF diet-induced endothelial dysfunction was completely prevented by PEG-OB (acetylcholine, EC50: SD saline, 335±113; HF saline, 758±164; HF PEG-OB, 277±85nmol/L; P<0.05). However, contraction to phenylephrine and relaxation to the NO donor, sodium nitroprusside, were unaltered between groups. Conclusions: PEG-OB exerts beneficial effects on hypertension and endothelial function in diabetes independently of metabolic actions suggesting that obestatin signalling may represent a novel therapeutic target to reduce the risk of associated cardiovascular complications.

Association of a Mediterranean type diet with age-related macular degeneration in the EUREYE study

Investigative Ophthalmology & Visual Science Volume 56 Issue 7 Pages 3760-3760

Molecular mechanisms mediating the beneficial metabolic effects of [Arg4]tigerinin-1R in mice with diet-induced obesity and insulin resistance

The frog skin host-defense peptide tigerinin-1R stimulates insulin release in vitro and improves glucose tolerance and insulin sensitivity in animal models of type 2 diabetes. This study extends these observation by investigating the molecular mechanisms of action underlying the beneficial metabolic effects of the analogue [Arg4]tigerinin-1R in mice with diet induced obesity, glucose intolerance and insulin resistance. The study also investigates the electrophysiological effects of the peptide on KATP and L-type Ca2+ channels in BRINBD11 clonal β cells. Non-fasting plasma glucose and glucagon concentrations were significantly (P<0.05) decreased and plasma insulin increased by twice daily treatment with [Arg4]tigerinin-1R (75 nmol.kg-1 body weight) for 28 days. Oral and intraperitoneal glucose tolerance were significantly (P < 0.05) improved accompanied by enhanced secretion and action of insulin. The peptide blocked KATP channels and, consistent with this, improved beta cell responses of isolated islets to a range of secretagogues. Peptide administration resulted in up-regulation of key functional genes in islets involved insulin secretion (Abcc8, Kcnj11, Cacna1c and Slc2a2) and in skeletal muscle involved with insulin action (Insr, Irs1, Pdk1, Pik3ca, and Slc2a4). These observations encourage further development of tigerinin-1R analogues for the treatment of patients with type 2 diabetes.

Performance of polarisation functionals for linear and nonlinear optical properties of bulk zinc chalcogenides ZnX (X=S,Se,Te).

We calculated the frequency dependent macroscopic dielectric function and second-harmonic generation of cubic ZnS, ZnSe and ZnTe within time-dependent density-polarisation functional theory. The macroscopic dielectric function is calculated in a linear response framework, and second-harmonic generation in a real-time framework. The macroscopic exchange–correlation electric field that enters the time-dependent Kohn–Sham equations and accounts for long range correlation is approximated as a simple polarisation functional αP, where P is the macroscopic polarisation. Expressions for α are taken from the recent literature. The performance of the resulting approximations for the exchange–correlation electric field is analysed by comparing the theoretical spectra with experimental results and results obtained at the levels of the independent particle approximation and the random-phase approximation. For the dielectric function we also compare with state-of-the art calculations at the level of the Bethe–Salpeter equation.

Developing Food Products For Consumers on a Gluten Free Diet

There is a significant increase in people that choose to follow an avoidance diet, especially excluding gluten. Unlike previously, there is now a demand for ‘no compromise’ gluten-free cereal products that have the same properties as their wheat contain counterparts. This is very challenging for the bakers and the cereal technologists due to the functional role of the gluten network in some of these products. Numerous combinations of raw materials form natural sources have been studied and critically evaluated in this review. Most of the gluten-free products are made of native and modified starches blended with different hydrocolloids due to their structure-building and water binding properties. These ingredients are added to a gluten-free flour, such as rice and corn. The legislation framework, formulations for manufacturing of highl nutritional value bread, pasta and cakes/biscuits as well as quality assurance aspects for the gluten-free manufacturers are discussed in this review.