Catalytic transfer hydrogenation of 7-ketolithocholic acid to ursodeoxycholic acid with Raney nickel

He Tian,Xuejun Cao,Hongbin Zhao 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.2

Ursodeoxycholic acid was produced by the stereoselective reduction of 7-ketolithocholic acid. This hydrogenation reaction was catalyzed by the T-1 Raney nickel and potassium borohydride was used as hydrogen donor instead of inflammable hydrogen gas. Potassium tert-butoxide was introduced to improve yield of ursodeoxycholic acid from about 70% to a maximum of 94% by inducing the stereoselectivity on hydroxyl group at 40 8C and atmospheric pressure. Reduction reaction conditions such as amount of reactants, temperature and stirring speed were optimized. The whole process is safe and low-cost. Eventually, the product, ursodeoxycholic acid was characterized by IR, 1H NMR and 13C NMR spectra.

Characterization of Solidification and Microstructure of an Al-Zn-Mg-Si Alloy

( He Tian ),( Dongdong Qu ),( Zherui Tong ),( Nega Setargew ),( Daniel J. Parker ),( David Stjohn ),( Kazuhiro Nogita ) 한국부식방식학회 2024 Corrosion Science and Technology Vol.23 No.2

Al-Zn-Mg-Si alloy coatings have been developed to inhibit corrosion of cold rolled steel sheets, and an understanding of the alloy system helps prevent coating defects. We used a Bridgman furnace to characterise the nature and formation mechanisms of the phases present in the quaternary system with 0.4 wt% Fe. In the directional solidification experiments we imposed steep temperature gradients and varied the pull rate. After the samples were quenched in the furnace, detailed characterization of the samples was carried out by electron microscopy (SEM/EDS). From the dT/dt vs T plots of the cooling curves of the alloys, the solidification path was determined to be Liquid → α-Al → Al/Mg₂Si → Al/Zn → Zn/ mgZn₂. The formation mechanisms of the Mg and Zn containing phases and their morphology was discussed together with the effects of the cooling rate. Key findings include the lengthening of the mushy zone in directionally solidified samples remelted against a positive temperature gradient, as well as an enrichening of the α-Al phase by Zn through remelting. Mg₂Si and other Si based phases were observed to adopt a much finer faceted microstructure in favour of a script-like microstructure when exposed to the higher cooling rate of coolant quenching.

Impacts of peat on nitrogen conservation and fungal community composition dynamics during food waste composting

He Zaihua,Li Qiang,Zeng Xiaoyi,Tian Kai,Kong Xiangshi,Tian Xingjun 한국응용생명화학회 2020 Applied Biological Chemistry (Appl Biol Chem) Vol.63 No.6

Peat, as a heterogeneous mixture of decaying plant debris and microbial residues, has been widely used in many fields. However, little research focused on the impact of peat addition on food waste composting. To fill this gap, a composting experiment of food waste mixed with five varying percent peat 0, 5, 10, 15, and 20% (w/w, dry weight) was designed to investigate the effect of different dosages of peat on nitrogen conservation, physiochemical parameters, and fungal community dynamics during composting. The results showed that adding peat elevated the peak temperature of composting, lowered final pH, reduced ammonia emissions and increased the final total nitrogen content. Compared to control, adding 5, 10, 15, and 20% peat decreased ammonia emissions by 1.91, 10.79, 23.73, and 18.26%, respectively, during 42 days of composting. Moreover, peat addition increased fungal community diversity especially during maturation phase. The most two abundant phyla were Basidiomycota and Ascomycota in all treatments throughout the composting process. At the end of composting, in treatments with adding 10 and 15% peat, the richest fungi were Scedosporium spp. and Coprinopsis spp., respectively. Simultaneously, canonical correlation analyses showed that pH, moisture content, and seed germination index had significant association with fungal community composition. The study also showed that fungal community and nitrogen conservation had no direct obvious relation during composting. Overall, the results suggest that the addition of peat could efficiently enhance nitrogen conservation through reduction of ammonia emissions and 15% peat addition is the optimal formula for food waste composting.

Distinct Electronic Structure for the Extreme Magnetoresistance in YSb

He, Junfeng,Zhang, Chaofan,Ghimire, Nirmal J.,Liang, Tian,Jia, Chunjing,Jiang, Juan,Tang, Shujie,Chen, Sudi,He, Yu,Mo, S.-K.,Hwang, C. C.,Hashimoto, M.,Lu, D. H.,Moritz, B.,Devereaux, T. P.,Chen, Y. L American Physical Society 2016 Physical Review Letters Vol.117 No.26

특집 : 『중국법연구중심』 개소식 기념 학술강연회 ; 중국형법개혁의 추세

전화 ( He Tian ) 연세대학교 법학연구원 2004 法學硏究 Vol.14 No.4

Infrared Image Edge and Texture Analysis Method based on Visual Habit

Yu Tian-he,Yu Xiao-yang,Dai Jing-min 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.10

The general edge extraction algorithm is not ideal to process infrared images, which is low contrast and blurred edge. In this paper, we used the multi-fractal spectrum to edge of infrared image. We extracted the edge information of the image and calculate the measure and fractal spectrum with multiple singular values of each pixel. Analysis of the similarities and differences of multiple measure, the function in edge extraction, meanwhile, analyzed the fiction of fractal characteristics to edge image extraction. This method differs from the traditional gradient algorithm,It determines whether the edge or not just according to the local extreme points , but according to the pixels in the local and global relationships to determine whether the pixel is a real edge. It can neglect important edge pixel and texture pixel,which is more in line with the human visual mental. It provide a good reference for recognition of infrared image and further processing.

關于當代中國精神倫理問題思考的思考

하조전 ( Zhao Tian He ) 국민대학교 중국지식네트워크 2015 중국지식네트워크 Vol.6 No.-

對흔多中國大陸人來說, 中國大陸近三十多年經濟上超速發展的령一面, 是精神文明方面驚人的不理想。而相比有越來越多的學界人士開始把中國大陸經濟奇迹作爲嚴肅硏究課題, 中國大陸在精神文明方面越來越嚴酷的現實, 雖然在實際生活中困擾着中國大陸絶大多數人, 却少有人把타作爲重要課題來認眞硏究思考, 少有人把타作爲要深入把握中國大陸近幾十年歷史和現實必不可少的理解、審問視角來對待。本報告則試圖對該如何硏究、思考中國大陸精神文明問題進行深入探討。 One hidden side of the rapid progress in China’s economic growth is that there’s not much of the equivalent advance in the field of spiritual civilization. While the growing number of academics started to consider the miraculous economic growth over the 30 years as the subject of a full-fledged study, few people took the state of spiritual culture as a serious challenge despite the fact that most people in everyday life were tormented by its wretched condition. What is worse, few people understand the importance of in-depth knowledge of the recent history and the effect of turbulent changes upon the society. This paper is going to review how to facilitate comprehensive discussion about the issues of spritual civilization in China, and to shed light on the situation which is far from ideal.

Multiplexed photoluminescent sensors: towards improved disease diagnostics

He, X. P.,Hu, X. L.,James, T.,Yoon, J.,Tian, H. Royal Society of Chemistry 2017 Chemical Society reviews Vol.46 No.22

Numerical simulation of three-dimensional flow and heat transfer characteristics of liquid lead-bismuth

He, Shaopeng,Wang, Mingjun,Zhang, Jing,Tian, Wenxi,Qiu, Suizheng,Su, G.H. Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.6

Liquid lead-bismuth cooled fast reactor is one of the most promising reactor types among the fourth-generation nuclear energy systems. The flow and heat transfer characteristics of lead-bismuth eutectic (LBE) are completely different from ordinary fluids due to its special thermal properties, causing that the traditional Reynolds analogy is no longer recommended and appropriate. More accurate turbulence flow and heat transfer model for the liquid metal lead-bismuth should be developed and applied in CFD simulation. In this paper, a specific CFD solver for simulating the flow and heat transfer of liquid lead-bismuth based on the k - 𝜀 - k_𝜃 - 𝜀_𝜃 model was developed based on the open source platform OpenFOAM. Then the advantage of proposed model was demonstrated and validated against a set of experimental data. Finally, the simulation of LBE turbulent flow and heat transfer in a 7-pin wire-wrapped rod bundle with the k - 𝜀 - k_𝜃 - 𝜀_𝜃 model was carried out. The influence of wire on the flow and heat transfer characteristics and the three-dimensional distribution of key thermal hydraulic parameters such as temperature, cross-flow velocity and Nusselt number were studied and presented. Compared with the traditional SED model with a constant Pr_t = 1.5 or 2.0, the k - 𝜀 - k_𝜃 - 𝜀_𝜃 model is more accurate on predicting the turbulence flow and heat transfer of liquid lead-bismuth. The average relative error of the k - 𝜀 - k_𝜃 - 𝜀_𝜃 model is reduced by 11.1% at most under the simulation conditions in this paper. This work is meaningful for the thermal hydraulic analysis and structure design of fuel assembly in the liquid lead-bismuth cooled fast reactor.

Curcumin modulates the apolipoprotein B mRNA editing by coordinating the expression of cytidine deamination to uridine editosome components in primary mouse hepatocytes

He, Pan,Tian, Nan The Korean Society of Pharmacology 2019 The Korean Journal of Physiology & Pharmacology Vol.23 No.3

Curcumin, an active ingredient of Curcuma longa L., can reduce the concentration of low-density lipoproteins in plasma, in different ways. We had first reported that curcumin exhibits hypocholesterolemic properties by improving the apolipoprotein B (apoB) mRNA editing in primary rat hepatocytes. However, the role of curcumin in the regulation of apoB mRNA editing is not clear. Thus, we investigated the effect of curcumin on the expression of multiple editing components of apoB mRNA cytidine deamination to uridine (C-to-U) editosome. Our results demonstrated that treatment with $50{\mu}M$ curcumin markedly increased the amount of edited apoB mRNA in primary mouse hepatocytes from 5.13%-8.05% to 27.63%-35.61%, and significantly elevated the levels of the core components apoB editing catalytic polypeptide-1 (APOBEC-1), apobec-1 complementation factor (ACF), and RNA-binding-motif-protein-47 (RBM47), as well as suppressed the level of the inhibitory component glycine-arginine-tyrosine-rich RNA binding protein. Moreover, the increased apoB RNA editing by $50{\mu}M$ curcumin was significantly reduced by siRNA-mediated APOBEC-1, ACF, and RBM47 knockdown. These findings suggest that curcumin modulates apoB mRNA editing by coordinating the multiple editing components of the edito-some in primary hepatocytes. Our data provided evidence for curcumin to be used therapeutically to prevent atherosclerosis.