Diamond Coated Wire Cutting of Solar Si Ingots: New Insights Using Raman Microspectroscopy

Diamond embedded abrasive wire (henceforth called diamond wire) sawing process of Si is a highly efficient technique for rapid wafering of solar Si ingots. However, the root causes for cutting efficiency losses are unknown. One approach to understanding this complex process is to study 1) diamond particles on diamond coated wire (DCW) and 2) Si swarf collected during cutting process. In this thesis, we use confocal, micro Raman spectroscopy to unravel loss mechanisms of wafer sawing efficiency. In the first part, we analyze the diamond microparticles which perform the sawing. By analyzing the phase transformation and stress distribution on single diamond particle, graphitization (i.e. softening of diamond) and residual stresses are observed. By studying the individual Si particles (swarf), correlations between particle shape and phase is established. Fibrillar Si particles are found to be amorphous – indicative of a ductile cut; while spherical Si articles are crystalline – indicative of a brittle cut. This important find helps to quantify the rates of cutting efficiency by simply measuring the entire Si swarf cluster; its phase distribution and stress change, as a function of Si swarf extraction time during the cutting process

Target profiling analyses of bile acids in the evaluation of hepatoprotective effect of gentiopicroside on ANIT-induced cholestatic liver injury in mice

AbstractEthnopharmacological relevanceGentiopicroside (GPS), one of iridoid glucoside representatives, is the most potential active component in Gentiana rigescens Franch. ex Hemsl and Gentiana macrophylla Pall. These two herbs have been used to treat jaundice and other hepatic and billiary diseases in traditional Chinese medicine for thousands of years.Aim of the studyThis study aimed to investigate the protective effects and mechanisms of GPS on α-naphthylisothiocyanate (ANIT) induced cholestatic liver injury in mice.Materials and methodsMice were treated with GPS (130mg/kg, ig) for 5 consecutive days. On the third day, mice were given a single dose of Alpha-naphthylisothiocyanate (75mg/kg, ig). Serum biochemical markers and individual bile acids in serum, liver, urine and feces were measured at different time points after ANIT administration. The expression of hepatic bile acid synthesis, uptake and transporter genes as well as ileum bile acid transporter genes were assayed.ResultsIn this study, ANIT exposure resulted in serious cholestasis with liver injury, which was demonstrated by dramatically increased serum levels of ALT, ALP, TBA and TBIL along with TCA CA, MCAs and TMCAs accumulation in both liver and serum. Furthermore, ANIT significantly decreased bile acid synthesis related gene expressions, and increased expression of bile acid transporters in liver. Continuous treatment with GPS attenuated ANIT-induced acute cholestasis as well as liver injury and correct the dyshomeostasis of bile acids induced by ANIT. Our data showed that GPS significantly upregulated the hepatic mRNA levels of synthesis enzymes (Cyp8b1 and Cyp27a1) and transporters (Mrp4 Mdr1 and Ost-β) as well as ileal bile acid circulation mediators (Asbt and Fgf15), accompanied by serum and hepatic bile acid levels decrease and further urinary and fecal bile acid levels increase.ConclusionGPS can change bile acids metabolism which highlights its importance in mitigating cholestasis, resulting in the marked decrease of intracellular bile acid pool back toward basal levels. And the protective mechanism was associated with regulation of bile acids-related transporters, but the potential mechanism warrants further investigation

Cu-Catalysed carboxylation of aryl boronic acids with CO₂

A copper/N-heterocyclic carbene (NHC) catalysed carboxylation of aryl boronic acids under one atmospheric pressure of CO₂ has been developed. A wide range of aryl boronic acids was transformed into benzoic acid derivatives in moderate to high yields. The carboxylation method shows excellent functional group compatibility, and sensitive functional groups such as carbonyls, esters, and nitriles were tolerated. Mechanistic studies revealed the vital role of the base in promoting the transmetalation step for this copper-catalysed carboxylation

Changes in element accumulation, phenolic metabolism, and antioxidative enzyme activities in the red-skin roots of Panax ginseng

AbstractBackgroundRed-skin root disease has seriously decreased the quality and production of Panax ginseng (ginseng).MethodsTo explore the disease's origin, comparative analysis was performed in different parts of the plant, particularly the epidermis, cortex, and/or fibrous roots of 5-yr-old healthy and diseased red-skin ginseng. The inorganic element composition, phenolic compound concentration, reactive oxidation system, antioxidant concentrations such as ascorbate and glutathione, activities of enzymes related to phenolic metabolism and oxidation, and antioxidative system particularly the ascorbate–glutathione cycle were examined using conventional methods.ResultsAluminum (Al), iron (Fe), magnesium, and phosphorus were increased, whereas manganese was unchanged and calcium was decreased in the epidermis and fibrous root of red-skin ginseng, which also contained higher levels of phenolic compounds, higher activities of the phenolic compound-synthesizing enzyme phenylalanine ammonia-lyase and the phenolic compound oxidation-related enzymes guaiacol peroxidase and polyphenoloxidase. As the substrate of guaiacol peroxidase, higher levels of H2O2 and correspondingly higher activities of superoxide dismutase and catalase were found in red-skin ginseng. Increased levels of ascorbate and glutathione; increased activities of l-galactose 1-dehydrogenase, ascorbate peroxidase, ascorbic acid oxidase, and glutathione reductase; and lower activities of dehydroascorbate reductase, monodehydroascorbate reductase, and glutathione peroxidase were found in red-skin ginseng. Glutathione-S-transferase activity remained constant.ConclusionHence, higher element accumulation, particularly Al and Fe, activated multiple enzymes related to accumulation of phenolic compounds and their oxidation. This might contribute to red-skin symptoms in ginseng. It is proposed that antioxidant and antioxidative enzymes, especially those involved in ascorbate–glutathione cycles, are activated to protect against phenolic compound oxidation

Cu-Catalysed carboxylation of aryl boronic acids with CO₂

A copper/N-heterocyclic carbene (NHC) catalysed carboxylation of aryl boronic acids under one atmospheric pressure of CO₂ has been developed. A wide range of aryl boronic acids was transformed into benzoic acid derivatives in moderate to high yields. The carboxylation method shows excellent functional group compatibility, and sensitive functional groups such as carbonyls, esters, and nitriles were tolerated. Mechanistic studies revealed the vital role of the base in promoting the transmetalation step for this copper-catalysed carboxylation

Traditional Chinese Medicine syndrome-related herbal prescriptions in treatment of malignant tumors

AbstractObjectiveTo investigate the distribution characteristics of TCM syndromes and the related herbal prescriptions for malignant tumors (MT).MethodsA clinical database of the TCM syndromes and the herbal prescriptions in treatment of 136 MT patients were established. The data were then analyzed using cluster and frequency analysis.ResultsAccording to the cluster analysis, the TCM syndromes in MT patients mainly included two patterns: deficiency of both Qi and Yin and internal accumulation of toxic heat. The commonly-prescribed herbs were Huangqi (Astraglus), Nüzhenzi (Fructus Ligustri Lucidi), Lingzhi (Ganoderma Lucidum), Huaishan (Dioscorea Opposita), Xiakucao (Prunella Vulgaris), and Baihuasheshecao (Herba Hedyotidis).ConclusionDeficiency of Qi and Yin is the primary syndrome of MT, and internal accumulation of toxic heat is the secondary syndrome. The herbs for Qi supplementation and Yin nourishment are mainly used, with the assistance of herbs for heat-clearance and detoxification

Transition-Metal-Free Borylation of Alkyl Iodides via a Radical Mechanism

We describe an operationally simple transition-metal-free borylation of alkyl iodides. This method uses commercially available diboron reagents as the boron source and exhibits excellent functional group compatibility. Furthermore, a diverse range of primary and secondary alkyl iodides could be effectively transformed to the corresponding alkylboronates in excellent yield. Mechanistic investigations suggest that this borylation reaction proceeds through a single-electron transfer mechanism featuring the generation of an alkyl radical intermediate