Molecular and cellular effects of green tea on oral cells of smokers: a pilot study

Studies in cell culture and laboratory animals have shown that green tea and its major component, epigallocatechin-3-gallate, inhibit cell growth and reduce tumor incidence. However, results of epidemiological studies have generated inconsistent, sometimes conflicting data regarding protection by green tea against human cancers. To clarify the findings of these laboratory studies in application to humans, we conducted a pilot intervention study with three heavy smokers (> 10 cigarettes/day) and three nonsmokers (never smokers) in order to evaluate the molecular and cellular effects of drinking green tea using human oral cells as an investigative tool. Green tea total extract (400-500 mg/cup, 5 cups/day) was administered in drinking water to the subjects for four weeks. Two oral cytology samples were taken weekly for measurements of tobacco carcinogen-induced DNA damage, including bulky adducts and oxidized bases, cell growth, DNA content, and apoptosis. The study showed that during the course of green tea administration smoking-induced DNA damage was decreased, cell growth was inhibited, and the percentage of cells in S phase was reduced, cells accumulated in G1 phase (cyclin D1 positive), DNA content became more diploid and less aneuploid, and p53, Caspase-3, and TUNEL, markers of apoptosis, were increased. The study, although preliminary, indicates that drinking green tea reduced the number of damaged cells in smokers by inducing cell growth arrest and apoptosis, a mechanism similar to that observed in cultured cells and animals. These results warrant a large-scale intervention trial to further verify the role of green tea in the prevention of oral cancer in smokers.     

Microbial Diversity of Ground Beef Products in South Korean Retail Market Analyzed by PCR-DGGE and 454 Pyrosequencing

The purpose of this study was to assess the microbial community in ground beef purchased from local stores in the north central area of South Korea. A total of 31 ground beef samples showed 3.77 ± 5.16 × 10⁵ CFU/g on aerobic plate counts, and PCR-based denaturing gradient gel electrophoresis was performed to assess the microbial community, which revealed a diverse profile among the products. Four of these samples were selected for further analyses via 454 pyrosequencing. Pseudomonas was the most frequently identified genus in terms of relative abundance (4.54–73.8%), and other bacteria such as Lactobacillus, Acinetobacter, and Carnobacterium were also identified in the ground beef. The presence of bacteria can affect the spoilage of ground beef products depending on the microbial populations, and understanding these populations may help limit spoilage and/or foodborne illness. This study illustrates the microbial diversity occurring among Korean ground beef products, even within a local region, and provides a molecular approach for potential ground beef microbial quality assessment.     

DETERMINATION OF DIMETHYL SUPLHIDE IN BEER BY GAS CHROMATOGRAPHY — COLLABORATIVE TRIAL

The Analysis Committee has collaboratively tested both routine headspace gas chromatographic methods and a standardised method for the determination of dimethyl sulphide in beer using the flame photometric and flame ionisation detectors available in the participating laboratories. The mean repeatability value (r₉₅) was 7.8 μg/litre for the concentration range 12–65 μg/litre, and the reproducibility value (R₉₅) showed the relationship R₉₅ = 18.1 + 0.452m μg/litre to the concentration (m). No differences in precision were attributed either to the methods or the types of detectors used.     

GLUCOSE OXIDASE REACTION FOR ESTIMATION OF GLUCOSE WITHOUT HORSERADISH PEROXIDASE. SOME MICROBIOLOGICAL AND FERMENTATION APPLICATIONS

An enzymic method has been developed for analysis of glucose. Glucose oxidase acts on glucose to produce hydrogen peroxide which acts to directly reduce the green Cu(II) 2–2′-bicinchoninate complex to a violet complex without horseradish peroxidase. A concentration range of 20–200 μM glucose was used but the reaction shows a linear range of 20–800 μM glucose. Interference is controlled by using a blank determination which has not been treated with glucose oxidase. The reaction has been used to estimate glucose levels in Saccharomyces cerevisiae fermentation and α-amylase, invertase and β-galactosidase reactions and coloured corn-steep fermentation media.     

On the Certification of Bonded Repairs to Primary Composite Aircraft Components

Airworthiness certification is required when bonded repairs are made to primary composite structure in situations where damage has reduced or has the potential to reduce residual strength to below the design ultimate strength. Generally, certification of bonded primary structure poses many difficulties. As most repairs are one-off events meeting these certification requirements is especially challenging since demonstration by testing will generally not be possible or cost-effective. This paper discusses options for addressing the two key issues relating to certification: (a) how to validate initial and enduring bond strength of adhesive bonds, mainly given the inability of conventional non-destructive inspection to provide this assurance and (b) how to develop acceptable generic design allowables for bonded repairs which represent actual failure modes – especially for cyclic loading, since validation by testing of simulated repairs will generally be infeasible. It is concluded that proof testing of bonded repair coupons is a promising approach for validating bond strength and fatigue testing of representative bond joint specimen can provide generic allowables for patch design. For hidden structure or very high value repairs structural health monitoring of repairs based on a strain-transfer approach offers considerable promise.     

Laser and GTAW torch processing of Fe–Cr–B coatings on steel

A comparison has been made of the relationship between microstructure and microhardness developed by surface melting Nanosteel SHS 7170 Fe–Cr–B alloy powder onto a plain carbon steel surface. This powder was initially developed as a high velocity oxyfuel sprayed coating, giving a strength 10 times that of mild steel, and is particularly suitable for surface protection against wear and corrosion. In the present study, the alloy powder was injected into the laser melted surface, while a preplaced powder was melted using the gas tungsten arc welding (GTAW) technique. The laser track consisted of fine dendrites and needle-like microstructures, which produced a maximum hardness value of over 800 HV, while the GTAW track produced a mixture of equiaxed and columnar grain microstructures with a maximum hardness value of 670 HV. The lower hardness values are considered to be associated with dilution and grain size.     

DNA-binding properties of the yeast transcriptional activator,Gcr1p

In Saccharomyces cerevisiae the GCR1 gene product is required for high-level expression of genes encoding glycolytic enzymes. In this communication, we extend our analysis of the DNA binding properties of Gcr1p. The DNA-binding domain of Gcr1p binds DNA with high affinity. The apparent dissociation constant of the Gcr1p DNA-binding domain for one of its specific binding sites (TTTCAGCTTCCTCTAT) is 2·9×10⁻¹⁰ M. However, competition experiments showed that Gcr1p binds this site in vitro with a low degree of specificity. We measured a 33-fold difference between the ability of specific competitor and DNA of random sequence to inhibit the formation of nucleoprotein complexes between Gcr1p and a radiolabeled DNA probe containing its binding site. DNA band-shift experiments, utilizing probes of constant length in which the positions of Gcr1p-binding sites are varied relative to the ends, indicated that Gcr1p–DNA nucleoprotein complexes contain bent DNA. The implications of these findings in terms of the combinatorial interactions that occur at the upstream activating sequence elements of genes encoding glycolytic enzymes are discussed.     

Thermal comfort in outdoor urban spaces: understanding the human parameter

The research being undertaken seeks to achieve a better understanding of the richness of microclimatic characteristics in outdoor urban spaces, and the comfort implications for the people using them. The underlying hypothesis is that these conditions influence people’s behaviour and usage of outdoor spaces. The initial results demonstrate that a purely physiological approach is inadequate in characterising comfort conditions outdoors, and an understanding of the dynamic human parameter is necessary in designing spaces for public use. The thermal environment is indeed of prime importance influencing people’s use of these spaces, but psychological adaptation (available choice, environmental stimulation, thermal history, memory effect, expectations) is also of great importance in such spaces that present few constraints.     

Carbon tetrachloride doped Al x Ga1−x As grown by metalorganic chemical vapor deposition

A dilute mixture of CCl₄ in H₂ has recently been shown to be a suitable carbon doping source for obtainingp-type GaAs grown by metalorganic chemical vapor deposition (MOCVD) with carbon acceptor concentrations in excess of 1 × 10¹⁹cm⁻³. To understand the effect of growth parameters on carbon incorporation in CCl₄ doped Al _x Ga_1−x As, carbon acceptor concentration was studied as a function of Al composition, growth temperature, growth rate, and CCl₄ flow rate using electrochemical capacitance-voltage profiling. The carbon incorporation as a function of Al composition, growth temperature and CCl₄ flow rate was also measured by secondary ion mass spectroscopy (SIMS). All layers were grown by low pressure MOCVD using TMGa and TMAl as column III precursors, and 100% AsH₃ as the column V source. Increased Al composition reduced the dependence of carbon concentration on the growth temperature. Reduced growth rate, which resulted in substantially decreased carbon acceptor concentrations in GaAs, had an insignificant effect on the carrier concentration of Al_0.4Ga_0.6As. A linear relationship between hole concentration and CC1₄ flow rate in Al_xGa_1−x As for 0.0 ≤x ≤ 0.8 was observed. These results are interpreted to indicate that adsorption and desorption of CCl _y (y ≤ 3) on the Al _x Ga_1-x As surface during crystal growth plays an important role in the carbon incorporation mechanism.