能缩小尺寸且不影响效果的天线技术

美国海军海底战争中心天线测试显示，一种名为DLM（Distributed Load Monopole）的新的天线技术能够使天线尺寸大大缩小，且不影响其性能。这一技术是Rhode Island大学Rob Vincent开发的，可以用于适合WLAN应用的贴装蜂窝电话天线生产，并且能够使对讲机的通话距离至少增加一倍。     

Chemical composition and antioxidant activities of Myrtus communis L. berries extracts

Myrtle (Myrtus communis L.) berries extracts were prepared with solvents at different polarity (water, ethanol, and ethyl acetate) and analysed using different in vitro tests in order to evaluate their antioxidant properties. Antiradical and total antioxidant activities were measured with DPPH and FRAP tests, respectively. Their ability to protect biological molecules was assessed using the cholesterol and LDL oxidation assays. In addition, phenolic compounds and unsaturated fatty acids composition was analysed by HPLC–DAD and HPLC–MS/MS. Ethanol and water extracts showed the highest amount of extracted compounds, but the highest antiradical and antioxidant activities were found in ethanol and ethyl acetate extracts. These extracts were also the ones with the highest content of phenolic compounds. In addition, our results showed a highly significant correlation between the amount of total phenols and antiradical (R² = 0.9993) or antioxidant activities (R² = 0.9985) in these extracts. HPLC–DAD and HPLC–MS analyses showed significant quantitative and qualitative differences among these three extracts. The ethyl acetate extract had the highest protective effect in assays of thermal (140 °C) cholesterol degradation and Cu²⁺-mediated LDL oxidation, inhibiting the reduction of polyunsaturated fatty acids and cholesterol, and the increase of their oxidative products. These results suggest that because of these properties, myrtle berries could be used in dietary supplements preparations or as food additives.     

Multivariate fatty acid and fatty alcohol profile of mullet bottarga

Mullet bottarga is a food delicacy obtained by salting and drying the intact roes of mullet (Mugil spp.). The fatty acid and fatty alcohol compositions of different samples of bottarga were studied by means of gas chromatography (GC) and multivariate analysis (MVA). High percentages of beneficial n‐3 PUFA, among which docosahexaenoic acid (DHA) (22:6n‐3, 11.9%) and eicosapentaenoic acid (EPA) (20:5n‐3, 8.6%), were detected. Differences in the concentrations of unsaturated FA and FAL were observed among samples, while saturated components showed little variations. On the other hand, the total contents of saturated, monounsaturated and polyunsaturated components were similar. The principal component analysis loadings bi‐plot showed that n‐6 PUFA concentrations were inversely correlated to those of n‐3 PUFA, except for DHA that showed no correlations. Correlations between FAL concentrations were also observed. Furthermore, integrating our GC data with those from the literature on mullet and tuna bottarga, the MVA showed that both bottarga typologies exhibit a similar trend in the FA distribution and that 16:0 and 16:1n‐7 FA are the variables with the highest discriminant power. In this work, we demonstrated the usefulness of the application of MVA to GC data to extract meaningful information otherwise hidden in the amount of data.     

Wine extracts from Sardinian grape varieties attenuate membrane oxidative damage in Caco-2 cell monolayers

One of the most important sites of polyphenol action seems to be in the gastrointestinal system before absorption. We investigated the ability of three wine phenolic extracts, obtained from grape varieties grown in Sardinia, Cannonau (red), Vermentino and Malvasia (white), to exert an antioxidant action against tert-butyl hydroperoxide (TBH)-induced oxidative damage to Caco-2 cell monolayers as a model system of the human intestine. TBH treatment caused the disruption of epithelial integrity, measured as transepithelial electrical resistance, and markers of the peroxidation process of membrane lipids, MDA, fatty acid hydroperoxides and 7-ketocholesterol. All wine extracts were able to counteract the oxidising action of TBH and, in spite of the differences in phenolic composition, exerted a comparable activity. Our findings point out a direct antioxidant action of the wine extracts on enterocytes exposed to oxidising species and further support the opinion that total phenolic content is not essential for antioxidant activity.     

低温金属环境中198Au半衰期的测量

利用德国鲁尔大学DTL实验室的中子源,通过¹⁹⁷Au(n,γ)¹⁹⁸Au反应得到¹⁹⁸Au@Au样品,在室温（T=293K）和低温（T=12K）条件下交替测量金属Au环境中¹⁹⁸Au的412keV特征γ射线,通过分析得到不同温度下198Au的半衰期。实验结果表明,与文献值T_1/2=（2.6943±0.0008）d相比,T=293K时¹⁹⁸Au的半衰期变长(0.4±0.7)%;T=12K时变长(4.0±0.7)%。这一变化趋向与德拜等离子体模型的预言相符,但其幅度显著小于模型的估计值。     

Do Synovial Inflammation and Meniscal Degeneration Impact Clinical Outcomes of Patients Undergoing Arthroscopic Partial Meniscectomy? A Histological Study

The menisci exert a prominent role in joint stabilization and in the distribution of mechanical loading. Meniscal damage is associated with increased risk of knee OA. The aim of this study was to characterize the synovial membrane and meniscal tissues in patients undergoing arthroscopic partial meniscectomy for meniscal tear and to evaluate association with clinical outcomes. A total of 109 patients were recruited. Demographic and clinical data were collected. Visual Analogic Scale (VAS) measuring pain and Knee injury and Osteoarthritis Outcome Score (KOOS) were recorded at baseline and at 2-years follow-up. Histological and immunohistochemical characterizations were performed on synovial membranes and meniscal tissues. More than half of the patients demonstrated synovial mononuclear cell infiltration and hyperplasia. Synovial fibrosis was present in most of the patients; marked vascularity and CD68 positivity were observed. Inflammation had an impact on both pain and knee symptoms. Patients with synovial inflammation had higher values of pre-operative VAS and inflammation. Higher pre-operative pain was observed in patients with meniscal MMP-13 production. In conclusion, multivariate analysis showed that synovial inflammation was associated with pre-operative total KOOS scores, knee symptoms, and pain. Moreover, meniscal MMP-13 expression was found to be associated with pre-operative pain in multivariate analysis. Thus, targeting inflammation of the synovial membrane and meniscus might reduce clinical symptoms and dysfunction at the time of surgery.     

众多元件亮相2005西部电子展

与Plastec、West Pack、太平洋设计与制造及医疗电子制造等诸多展览会同地举行的2005西部电子展(Electronics West 2005)吸引了来自众多不同学科领域的OEM制造商。以下是部分参展产品。     

An evaluation of the Diamat HPLC analyser for simultaneous determination of haemoglobins A2 and F

The authors describe a modification of the instrumental parameters of the Diamat fully automated HPLC system for Hb A₂ assay (Bio-Rad Laboratories, Milan, Italy) in order to obtain simultaneous determination of Hb A₂ and Hb F.Hb A₂ and Hb F measurements are reproducible (within-run CV 2.6%, with Hb A₂2.7%; 5.1%, with Hb F 1.3%) and accurate (from a comparison with two microchromatographic techniques for Hb A₂: r = 0.9639 and 0.9755; with two alkali denaturation procedures for Hb F: r = 0.9990 and 0.9952; with radial immunodiffusion, r = 0.9877). Assay linearity has been confirmed for Hb A₂ concentrations between 0 and 6.0%, and for Hb F between 0 and 60%. The data obtained from the analysis of some pathological samples for Hb Bart''s, Hb H, Hb J Sardegna, Hb Lepore and Hb S are in agreement with cellulose acetate electrophoresis analysis.The Hb A₂ reference intervals for normals (N = 597) and Beta-thalassemia carriers (N = 200) are respectively (95% limits) 2.02-3.27 and 3.92-5.90 in % units. Hb F values measured in normals (N = 968), in β-thal carriers (N = 302) and in δβ-thal carriers (N =3) have been found to be consistent with the usual diagnostic parameters.Some minor limitations emerged: the most relevant concerns Hb A_1c, which is overestimated with respect to a reference method (y = 1.217x + 0.16; N = 79; r = 0.9235). A probable interference from labile fractions is responsible for this Hb A_1c inaccuracy.