The In Vivo Antioxidant and Hepatoprotective Actions of Selected Chinese Teas.

Tea is a popular beverage and shows very strong in vitro antioxidant activity. However, the relationship among in vitro and in vivo antioxidant activities in teas is seldom reported. In this study, in vivo antioxidant and hepatoprotective activities of 32 selected Chinese teas were evaluated on a mouse model with acute alcohol-induced liver injury. The results showed that most teas significantly reduced the levels of alanine transaminase, aspartate transaminase, alkaline phosphatase, triacylglycerol, and total bilirubin in the sera of mice at a dose of 400 mg/kg. In addition, most teas greatly decreased the malondialdehyde level and increased the levels of superoxide dismutase, glutathione peroxidase, and glutathione in the liver of mice, indicating the antioxidant and hepatoprotective activities of teas. Furthermore, the in vivo antioxidant activity of dark tea was stronger than that of green tea, opposite to the results of the in vitro study. Among these 32 teas, Black Fu Brick Tea, Pu-erh Tea, and Qing Brick Tea showed the strongest antioxidant and hepatoprotective activities. Moreover, total phenolic content as well as the contents of epicatechin, gallocatechin gallate, and chlorogenic acid were found to contribute, at least partially, to the antioxidant and hepatoprotective actions of these teas. Overall, teas are good dietary components with antioxidant and hepatoprotective actions.

Reliability Analysis of CFRP-Strengthened RC Bridges Considering Size Effect of CFRP.

A reliability analysis of an existing structure and a carbon fiber-reinforced plastic (CFRP)-strengthened structure is commonly used to evaluate the effectiveness of strengthening. It also provides the basis for the calibration of the partial factors involved in strengthening design codes. As the fundamental data, the statistical characteristics of the CFRP tensile strength affect the evaluation result. In general, the statistical characteristics of the CFRP strength were obtained from laboratory experiments with small-scale specimens, which resulted in errors caused by the size effect. In this study, a probabilistic series-parallel model is developed to describe the size effect of CFRP. The CFRP fabric is divided into a set of representative volume elements. By numerically simulating the CFRP strength, the relationship between the number of representative volume elements and the mean and coefficient of variation (COV) of the CFRP strength is analyzed. A chi-square test is carried out to determine the distribution type of the CFRP strength. An analytical expression of the mean, COV, and the cumulated density function of the CFRP strength are derived. Finally, an existing bridge, which has operated for 41 years, is selected for the case study; it is strengthened by using CFRP fabric. Reliability indexes of the existing and the strengthened bridges are calculated to analyze the size effect on the reliability of the strengthened structure.

Effects and Mechanisms of Tea for the Prevention and Management of Diabetes Mellitus and Diabetic Complications: An Updated Review.

Diabetes mellitus has become a serious and growing public health concern. It has high morbidity and mortality because of its complications, such as diabetic nephropathy, diabetic cardiovascular complication, diabetic neuropathy, diabetic retinopathy, and diabetic hepatopathy. Epidemiological studies revealed that the consumption of tea was inversely associated with the risk of diabetes mellitus and its complications. Experimental studies demonstrated that tea had protective effects against diabetes mellitus and its complications via several possible mechanisms, including enhancing insulin action, ameliorating insulin resistance, activating insulin signaling pathway, protecting islet ß-cells, scavenging free radicals, and decreasing inflammation. Moreover, clinical trials also confirmed that tea intervention is effective in patients with diabetes mellitus and its complications. Therefore, in order to highlight the importance of tea in the prevention and management of diabetes mellitus and its complications, this article summarizes and discusses the effects of tea against diabetes mellitus and its complications based on the findings from epidemiological, experimental, and clinical studies, with the special attention paid to the mechanisms of action.

A Highly Sensitive Colorimetric Method for Copper Ions Detection Based on Controlling the Peroxidase-like Activity of Au@Pt Nanocatalysts.

In this study, a sensitive colorimetric method for the detection of copper ion (Cu2+) was developed based on controlling the peroxidase-like activity of (gold core)@(ultrathin platinum shell) nanocatalysts (Au@Pt-NCs). It was found that D-penicillamine can effectively inhibit the activity of Au@Pt-NCs. After being incubated with Cu2+, D-penicillamine lost inhibition toward the catalytic ability of Au@Pt-NCs. Based on the above interaction, a colorimetric detection of Cu2+ was develop by measuring the colorimetric signal variation of the H2O2-3,3',5,5'-tetramethylbenzidine (TMB) reaction. This method exhibited high sensitivity and selectivity toward Cu2+ over a panel of other metal ions. The detection limit of this method was 3.7 nM and the linear range was 20 - 300 nM. Moreover, 20 nM Cu2+ can be distinguished directly by the naked eye. Furthermore, this method was applied to the analysis of water samples with good accuracy. These results demonstrated the excellent application potential of the method.

Using FTIR spectra and pattern recognition for discrimination of tea varieties.

In order to classify typical Chinese tea varieties, Fourier transform infrared spectroscopy (FTIR) of tea polysaccharides (TPS) was used as an accurate and economical method. Partial least squares (PLS) modeling method along with a self-organizing map (SOM) neural network method was utilized due to the diversity and heterozygosis between teas. FTIR spectra results of tea extracts after spectra preprocessing were used as input data for PLS and SOM multivariate statistical analyses respectively. The predicted correlation coefficient of optimization PLS model was 0.9994, and root mean square error of calibration and cross-validation (RMSECV) was 0.03285. The features of PLS can be visualized in principal component (PC) space, contributing to discover correlation between different classes of spectra samples. After that, a data matrix consisted of the scores on the selected 3PCs computed by principle component analysis (PCA) and the characteristic spectrum data was used as inputs for training of SOM neural network. Compared with the PLS linear technique's recognition rate of 67% only, the correct recognition rate of the PLS-SOM as a non-linear classification algorithm to differentiate types of tea reaches up to 100%. And the models become reliable and provide a reasonable clustering of tea varieties.

Synthesis, molecular docking and kinetic properties of ß-hydroxy-ß-phenylpropionyl-hydroxamic acids as Helicobacter pylori urease inhibitors.

Inhibition of urease results in Helicobacter pylori growth arrest in the stomach, promoting urease as promising targets for gastrointestinal ulcer therapy. Twenty hybrid derivatives of flavonoid scaffold and hydroxamic acid, ß-hydroxy-ß-phenylpropionylhydroxamic acids, were therefore synthesized and evaluated against H. pylori urease. Biological evaluation of these compounds showed improved urease inhibition exhibiting micromolar to mid-nanomolar IC50 values. Most importantly, 3-(3-chlorophenyl)-3-hydroxypropionyl-hydroxamic acid (6g) exhibited high potency with IC50 of 0.083±0.004 µM and Ki of 0.014±0.003 µM, indicating that 6g is an excellent candidate to develop novel antiulcer agent. A mixture of competitive and uncompetitive mechanism was putatively proposed to understand the inconsistency between the crystallographic and kinetic studies for the first time, which is supported by our molecular docking studies.

[Exploration of the broken parts of a brake hose by ATR-FTIR and SEM].

ATR-FTIR and SEM were respectively utilized to analyze the chemical components and to observe the micromorphology of a broken brake hose from a traffic case, which could be a supplementary for the traditional microscopic examination. The instrumental analysis results indicated that the rubber from the brake hose had already aged; the rubber from external side had experienced brittle fracture and there were original hollows in the rubber from internal side. The breaking of the brake hose resulted from all these reasons. The experimental results also demonstrated that the fact could be reflected efficiently, accurately and objectively by the application of ATR-FTIR and SEM to the physical evidence from a case. Therefore, it could be an effective complement for traditional traffic trace examination.

Application of CdSe nanoparticle suspension for developing latent fingermarks on the sticky side of adhesives.

Nanometer-sized fluorescent particles were synthesized in an aqueous solution using TGA (mercaptoacetic acid) as the stabilizer. The prepared solution was characterized by fluorescence spectroscopy and applied for detection of latent fingermarks on adhesives. The effects of stabilizer, precursor, pH value, the concentration of cadmium ion and shell structure on fluorescence were also discussed. The results indicated that the intensity of fluorescence was remarkably increased and the selectivity was well improved when using CdSe nanoparticles, it produced significantly less background development and better contrast after 15 min developing process.

Application of photoluminescent CdS/PAMAM nanocomposites in fingerprint detection.

Uniform and well-dispersed photoluminescent semiconductor CdS (cadmium sulfide) QDs (quantum dots) were in situ prepared inside Generation 4.0-NH(2) PAMAM (polyamidoamine) dendrimers in methanol, methanol and water mixed solutions of volume ratio 1:9, respectively. The prepared solutions containing photoluminescent semiconductor CdS QDs were utilized for detection of cyanoacrylate ester fumed fingerprints on tinfoil. The results show that fumed latent fingerprints treated with prepared CdS/PAMAM nanocomposites in methanol, 1:9 methanol:water mixed solutions emit pale yellow-green and orange luminescence respectively under ultraviolet excitation of 365 nm from an UV LED. Fumed fingerprints were successfully detected with good resolving rate and the mechanism was studied in detail.

[Study on amidation reaction between CdS/PAMAM and amino acid and its application to latent fingerprint development].

A new method for the development of latent fingerprints by CdS/PAMAM nanocomposites was explored in the present research. Amidation reaction between terminal carboxylate groups of amino acids and terminal amino groups of PAMAM G4. 5 dendrimers was studied by FTIR spectrometry. The reacting processes under different conditions were monitored by H(1267/1735) (the relative ratio of peak height) in order to find out the optimized condition and developing method. The results indicated that the reacting processes were affected remarkably by the changes in temperature. The reaction was efficient under 90 degrees C within 4 hours, while the reacting speed decreased after 3 hours under 120 degrees C. CdS/PAMAM was utilized as the latent fingerprint developing reagent and compared with the routine one. The results indicated that the fluorescence intensity of the former is 65 times higher than that of the latter. Great predominance in florescence could be observed when CdS/PAMAM and the routine developing reagent were compared. Latent fingerprints on the surface of different objects were developed under 120 degrees C within 0.5-3 h. Good developing results could be obtained under the optimized condition. The method is simple, rapid, highly sensitive, safe and economical.