Microstructure and mechanical properties of aluminum alloy 1421 after ECAP and warm rolling

The process of equichannel angular pressing (ECAP) is studied with the aim of fabricating large-size preforms with a diameter of 40 mm and a length of 160 mm from alloy 1421 to be used for forming sheets by subsequent warm rolling. Special features of the microstructure and optimum modes of superplasticity and mechanical properties of sheets with ultrafine-grain (UFG) structure are considered. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 3, pp. 45–48, March, 2007.     

Superplasticity of nanostructured metallic materials obtained by methods of severe plastic deformation

A review of primarily the authors’ own works on the effect of nano-and submicrocrystalline structure obtained by methods of severe plastic deformation, such as equal channel angular pressing and severe plastic deformation by torsion, on the superplasticity of alloys at relatively low temperature and/or high deformation rate is presented. Special features of the microstructure (grain size, grain-boundary angles, phase composition) required for manifestation of the effect of enhanced superplasticity in ultrafine-grained metals are considered. Special attention is devoted to the effect of grain refinement and development of grain boundary sliding in low-temperature and high-temperature superplasticity. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 5–10, February, 2006.     

Lipid Fractions,Fatty Acid Profiles,and Bioactive Compounds of Lithospermum officinale L. Seeds

Seeds of Lithospermum officinale L. from different climatic zones were analyzed for new sources of γ-linolenic acid (GLA, 18:3n-6) and stearidonic acid (SDA, 18:4n-3). Cultured Borago officinalis was also analyzed for comparative purposes. Analyses were conducted for fatty acid (FA) profiles of the glyceride oils from the seeds and in the neutral and polar lipids by gas chromatography (GC); lipid classes by open column chromatography and preparative thin layer chromatography (TLC); and tocopherols, sterols, and phenolic compounds by high-performance liquid chromatography with diode array detection (HPLC-DAD), and the later compounds were confirmed by liquid-chromatography-mass spectrometry (LC–MS). L. officinale from St. Petersburg Botanical Garden showed the highest percentage of GLA (17.9% of total FA), while wild-growing L. officinale from the Rostov region contained the highest percentage of SDA (17.2% of total FA). Total FA content ranged from 11.3 to 20.8% of seed weight. Neutral and polar lipids accounted for ~98 and 2.27%, respectively, of total lipids. Five neutral lipid classes were identified (% of NL): triterpene esters (1.3), triacylglycerols (93.1), free FA (1.8), diacylglycerols (1.4), and monoacylglycerols (2.4). The highest tocopherol content was found in samples from Chechen Republic (35.7 mg/100 g), in which the δ isomer was the main component. Samples from the Rostov region had the highest amounts of sterols (83.8 mg/100 g), and Δ⁵-avenasterol was the predominant compound in all samples. L. officinale seeds contain high amounts of phenolic compounds (389.9 mg/100 g as upper limit), in which rosmarinic acid is highlighted. Overall, all data suggest the possibility of using L. officinale seed oil in pharmaceutical and cosmetic formulae and as functional food.     

Comparison of ginsenosides in radix and rhizome of wild Panax species using LC‐ELSD and LC‐Q‐TOF‐MS

High‐performance liquid chromatography (HPLC) with evaporative light scattering detector (ELSD) and quadrupole time‐of‐flight mass spectrometry (Q‐TOF‐MS) were used for qualitative and quantitative analysis of wild Panax species, especially wild P. vietnamensis, which is an important medicinal plant. We determined the types and concentrations of ginsenosides in radix and rhizome of wild P. vietnamensis. Identification of ginsenosides was achieved using Q‐TOF‐MS; concentrations were determined by ELSD. The most abundant ginsenosides in wild Vietnamese ginseng were of the ocotillol type, accounting for more than 50% of the total. Compared to the rhizome, the radix had 31% higher ginsenoside content due to variation in protopanaxatriol‐type ginsenoside contents. We also found an unusual difference in the chromatograms of the two parts of wild P. vietnamensis. This difference did not appear in other wild species such as P. ginseng and P. quinquefolius. Our study provides an opportunity for further in‐depth study of the distinctive characteristics of P. vietnamensis.