Defect engineering in nanozymes

Due to the high stability, various synthesis strategies, low cost, and tunable performance, nanozymes have gained much attention as the replacement of natural enzymes. To widen the application, highly active, specific, and robust nanozymes are in need. Recently, defects in nanomaterials have been verified to play a significant role in enhancing catalytic performances. Therefore, the marriage between defect engineering and nanozymes is expected to spark new possibilities. In this review, defect engineering strategies in nanozymes are summarized and the close relationships between defects and nanozyme properties are highlighted. It is anticipated that defect engineering will bring new opportunities to the evolving field of nanozymes.     

Tea consumption and disease correlations

Tea is the most widely consumed beverage in the world next to water and is obtained from the leaves Camellia sinensis. In recent years, the potential health benefits and effect mechanisms of tea have attracted a lot of interest. The potential health benefits of tea have been attributed to its various phenolic compounds with unique biological properties found in tea. These phenolic compounds are especially catechins and their derivatives, which constitute at most 30% of the dry weight of the tea. Tea is a new and effective strategy for reducing the severity of neurological diseases and for protecting against obesity, cardiovascular disease, type 2 diabetes and certain types of cancer (ovaryum, lung, skin, breast, endometrial, prostate, bladder, oral and colorectal cancers).Overall, the study that supports the health benefits of tea is increasing. But, the amounts of and the frequency of tea consumption that is associated with potential health benefits vary greatly from work to work and this situation creates difficulty in determining the optimal consumption amount and frequency that tea can exhibit health benefits. For this reason, we aimed to examine the health effect of the tea and how much consumption is to investigate whether it meets the claimed health benefits.Within that frame, there is a need for more studies on the possible health effects of tea. While studying on that effect, the effects of various doses, forms (in synthetic or natural product matrix), exposure in different periods (short or long term) on health should be studied. However, currently the conducted studies are promising for tea is a bioactive component like polyphenol, theaflavins, thearubigins, caffeine and mineral. In addition, although the fact intake with diet proved to be reliable at the end of the conducted acute and chronic toxicity test is another positive part, safety of bioactive component in tea should be supported through further studies.     

Large artificial neural networks applied to the prediction of retention indices of acyclic and cyclic alkanes,alkenes, alcohols,esters, ketones and ethers

Artificial neural networks (ANN) with extended delta-bar-delta (EDBD) back propogation learning algorithms were used to predict the retention indices of 184 organic compounds. These compounds include acyclic and cyclic alkanes, alkenes, alcohols, esters, ketones and ethers. The network's architecture and parameters were optimized to give maximum performance. The best network is 2–6–1, the optimum learning epoch is 2000. In the process of the study, cross-validation and leave-20%-out were used. The results show that the prediction performance of ANN operating with such non-linear systems is remarkably good.     

Microcomputer controlled arc oscillator for automated TIG welding

A magnetic arc oscillation system has been developed to control the fusion characteristic of arc welding. A single-pole electromagnet generates a transverse magnetic field parallel to the weld line. The weave pattern of the magnetic field, hence the bead geometry, is controlled by a custom-built computer. The applied magnetic field has a marked influence on the bead width, but less on the bead depth. Experiments also show that bead appearance is improved by magnetically oscillating the arc.     

Lipid-lowering action of pectin from Cucumis sativus

The oral administration of the pectin extracted from the fruit of Cucumis sativus at a dose of 5 g kg⁻¹ body weight day⁻¹ showed significant hypolipidemic action in normal as well as cholesterol-fed experimental animals. Concentrations of cholesterol, triglycerides, phospholipids and free fatty acids were found to be significantly reduced in the serum and tissues of experimental animals. Activity of HMG CoA reductase was found to be enhanced. Pectin administration decreased the activities of glucose-6-phosphate dehydrogenase and malate dehydrogenase while it increased the activities of lipoprotein lipase and plasma LCAT. Incorporation of labelled ¹⁴C acetate into free cholesterol was significantly higher in the liver of pectin-treated rats. Concentrations of bile acids (hepatic and fecal) and fecal neutral sterols showed significant increases in the pectin-administered groups.     

How do oxyphytosterols affect human health?

Oxyphytosterols are similar to oxycholesterols in structure, and they exhibit pro-atherogenic properties. Recently, more interests were focused on the metabolism of oxyphytosterols for their increasing intake from phytosterol-enriched food. In this review, we discussed the origin, absorption, distribution, and transport of oxyphytosterols in vivo and their biological effects in humans. The two dominant oxyphytosterols in human plasma are 7-keto-sitosterol and 7-keto-campesterol, but their origins are unclear. It is suggested that oxysitosterols are formed to eliminate sitosterol from tissue to the blood stream. Aside from the pro-atherogenic, oxyphytosterols also exhibit pro-inflammatory properties and antiviral activity against equine herpesvirus 1. Further research is needed to investigate the physiological and pathological role of oxyphytosterols in humans.     

Physicochemical properties of waxy and normal corn starches treated in different anhydrous alcohols with hydrochloric acid

Corn starches (25 g, d. b.) were treated in anhydrous methanol, ethanol, 2-propanol or 1-butanol (100 ml) with 1 ml 36% hydrochloric acid at 45 °C for 1 h, the molecular weight and chain length distributions of starch were examined by high-performance size-exclusion chromatography (HPSEC), and the granule size, granular structure, λ_max, blue value, solubility and gelatinization thermal properties of starch were also examined. Results showed the recovery yields of the treated starch were higher than 96%, and the granule sizes of treated starches were slightly lower than their counterpart native starch. Starches after acid-alcohol treated showed internal fissures or cavities in some granules, and the number of granule with fissures or cavities increased with the increasing carbon number of alcohol. The weight average degree of polymerization and relative content of F1 fraction of starch after treated profoundly decreased, and the amylose and long chain of amylopectin of starch were preferentially degraded. The degradation extent of molecules after acid-alcohol treatment was found directly related to the alternation of internal structure of starch granule. The λ_max and blue value of both waxy and normal corn starches after treated also obviously decreased with the increasing carbon number of alcohol, while the solubility of starch profoundly increased after treated. The gelatinization onset temperature (T_o) of acid-alcohol treated waxy corn starch decreased with the increasing carbon number of alcohol, but the treated normal corn starches showed similar T_o values. Despite the alcohol used, the solubility of treated waxy corn starch linearly correlated (r²=0.983) with T/T_o value (T was the measuring temperature used for solubility determination). Whereas, normal corn starch treated in different alcohols showed distinct relations between T/T_o and solubility.     

Effect of rapid solidification on giant magnetostriction in ferromagnetic shape memory iron-based alloys

Ferromagnetic shape memory Fe–29.6 at.% Pd alloy ribbons prepared by the rapid solidification, melt-spinning method, showed a giant magnetostriction of 830 microstrain when an external magnetic field of 7 kOe was applied nearly normal to the ribbon surface at room temperature. This ribbon's magnetostriction was several times as large as conventional polycrystalline bulk's one before rapid solidification. The magnetostriction in the rolling direction depended strongly on a direction of applied magnetic field. We considered that this phenomenon is caused by a rearrangement of activated martensite twin variants just below the austenite phase transformation temperature. We investigated their basic material properties, i.e. the dependencies of magnetostriction on temperature as well as on magnetic angular orientation to the surface, magnetic properties, crystal structure, surface texture morphology and shape memory effect of Fe–29.6 at.% Pd ribbon samples by comparing with conventional bulk sample. It can be concluded that the remarkable anisotropy of giant magnetostriction of ribbon sample is caused by the unique uniaxial-oriented fine grain structure formed by the melt-spinning method. In addition, we confirmed the possibility of rapidly solidified Fe–Pt ribbon as a new kind of iron-based ferromagnetic shape memory alloys for magnetostrictive material.