Aluminum based reflective nanolens arrays to improve the effectiveness of ultraviolet inactivation of Escherichia coli O157:H7 and Listeria monocytogenes in water and a sucrose solution

Food Science and Biotechnology - Aluminum based reflective nanolens arrays were developed via a series of aluminum electropolishing and anodization steps with subsequent selective dissolution of...     

Isolation and identification of an antiproliferative substance from fructose–tyrosine Maillard reaction products

We isolated a substance from fructose–tyrosine Maillard reaction products (MRPs) and investigated its antiproliferative effect on six human cancer cell lines. The ethyl acetate fraction of fructose–tyrosine MRPs showed a strong antiproliferative effect; this fraction was isolated and purified using silica gel column chromatography, semipreparative RP-HPLC, and recycling HPLC. The structure of the purified compound was determined using spectroscopic methods. The isolated compound was identified as 2,4-bis(p-hydroxyphenyl)-2-butenal (C₁₆H₁₄O₃, HPB242). HPB242 inhibited cell growth in a dose-dependent manner (10–80 μg/ml) on the six human cancer cell lines. The IC₅₀ values of HPB242 on the six human cancer cell lines were 17.34 μg/ml (MCF-7), 29.21 μg/ml (HCT-116), 34.57 μg/ml (H-460), 34.87 μg/ml (HepG2), 48.77 μg/ml (PC-3), and 55.83 μg/ml (MKN-45).     

Antioxidant activities and contents of phytochemicals in methanolic extracts of specialty rice cultivars in Korea

Rice is an important agricultural commodity and a major staple food in Asian diets. The aims of this study were to investigate the antioxidant activities and phytochemical contents of methanolic extracts from specialty rice cultivars and to determine if there is any correlation between antioxidant activity and phytochemical content. Our results indicate that methanolic extracts from different rice cultivars contain different levels of phenolics, anthocyanin, carotenoids, γ-oryzanol, and vitamin E. Black rice cultivars such as ‘Heugkwang’, ‘Heugseol’, and ‘Heugjinju’ contained higher phytochemical contents compared to other cultivars. In contrast, the cultivars ‘Segyejinmi’, ‘Cheonseok’, ‘Hanareum’, and ‘Dasan 1’ contained significantly higher levels of γ-tocotrienol compared with other cultivars. The black rice cultivars also showed higher antioxidant activities. Phenolic content was positively correlated with DPPH and ABTS radical scavenging activities and reducing power. The results could have a direct impact on rice consumption by enhancing consumer awareness of health benefits of the rice.     

ADL tests for threshold cointegration

In this article, we propose new tests for threshold cointegration using an autoregressive distributed lag (ADL) model. The indicators in the threshold model can adopt either a nonstationary or stationary threshold variable. The cointegrating vector is not prespecified in this article. We adopt a supremum Wald type test to account for the so‐called Davies (1987, Biometrika 74 ,33) problem. The asymptotic null distributions of the proposed tests are free of nuisance parameters. As such, a bootstrap procedure is not required and the critical values of the proposed tests are tabulated. Monte Carlo experiments show good finite‐sample performance.     

Antioxidant and antiproliferative activities of grape seeds from different cultivars

Grape seeds contain high levels of phytochemicals, which have been correlated with a decreased risk of chronic diseases. In this study, grape seeds from 10 different cultivars (‘SV 18315’, ‘Naples’, ‘Agawam’, ‘Aligote’, ‘V.50151’, ‘Cabernet Sauvignon’, ‘Urbana’, ‘Baco22A’, ‘Clinton’, and ‘Campbell Early’) were evaluated for their antioxidant and antiproliferative activities. The antioxidant activity of the grape seeds was evaluated by radical scavenging activities and reducing power. The antiproliferative activity was assessed by the inhibition of MCF7, NCI-H460, HCT116, and MKN45 cancer cell proliferation. The total polyphenol and flavonoid contents were determined by spectrophotometric methods. ‘Cabernet Sauvignon’ and ‘Baco22A’ had high polyphenol (4,369.2 and 3,747.0 mg/100 g seeds) and flavonoid contents (3,072.7 and 2,032.9 mg/100 g seeds). ‘Cabernet Sauvignon’ and ‘Baco22A’ also possessed the highest radical scavenging activity. In addition, these were showed generally higher antiproliferative activity than other cultivars. Both the polyphenol and flavonoid contents were positively correlated with radical scavenging activity (R²>0.9). These results may provide basic information about health-beneficial effects of grape seeds.     

Thermal Conductivity and Thermal Boundary Resistances of ALD Al$$_{}$$O$$_{3}$$3 Films on Si and Sapphire

On Si and sapphire substrates, 6–45 nm thick films of atomic layer-deposited Al\(_{2}\)O\(_{3}\) were grown. The thermal conductivity of ALD films has been determined from a linear relation between film thickness and thermal resistance measured by the 3\(\omega \) method. ALD films on Si and sapphire showed almost same thermal conductivity in the temperature range of 50–350 K. Residual thermal resistance was also obtained by extrapolation of the linear fit and was modeled as a sum of the thermal boundary resistances at heater–film and film–substrate interfaces. The total thermal resistance addenda for films on sapphire was close to independently measured thermal boundary resistance of heater–sapphire interface. From the result, it was deduced that the thermal boundary resistance at ALD Al\(_{2}\)O\(_{3}\)–sapphire interface was much lower than that of heater–film. By contrast, the films on Si showed significantly larger thermal boundary resistance than films on sapphire. Data of \(< 30\) nm films on Si were excluded because an AC coupling of electrical heating voltage to semiconductive Si complicated the relation between 3\(\omega \) voltage and temperature.