L-Theanine-Treated Adipose-Derived Mesenchymal Stem Cells Alleviate the Cytotoxicity Induced by N-Nitrosodiethylamine in Liver

Lai Yun-Ju,Sung Yi-Ting,Lai Yi-An,Chen Li-Nian,Chen Tung-Sheng,Chien Chiang-Ting 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.6

BACKGROUND: Liver inflammation is the main cause of severe liver diseases, including liver fibrosis, steatohepatitis, cirrhosis and hepatocellular carcinoma. Cell therapy topics are receiving increasingly more attention. The therapeutic applications of mesenchymal stem cells (MSC) have become one of the most discussed issues. While other stem cells have therapeutic effects, they have only one or two clinical applications. MSCs are responsible for repairing a variety of tissue injuries. Moreover, MSCs could be derived from several sources, including adipose tissue. MSCs are usually more abundant and easier to obtain compared to other stem cells. METHODS: To prove the concept that MSCs have homing ability to the injured tissue and assist in tissue repair, we examined the effects of intravenous injected adipose-derived mesenchymal stem cells (ADSCs) in a N-nitrosodiethylamine (DEN)-induced liver injury rat model. RESULTS: The significant repairing ability of ADSCs was observed. The levels of fibrosis, apoptosis, and tumorigenesis in the DEN-injured liver tissues all decreased after ADSC treatment. Furthermore, to enhance the therapeutic effects of ADSCs, we pretreated them with L-theanine, which promotes the hepatocyte growth factor secretion of ADSC, and therefore improved the healing effects on injured liver tissue. CONCLUSION: ADSCs, especially L-theanine-pretreated ADSCs, have anti-inflammation, anti-apoptosis, and anti-tumorigenesis effects on the N-nitrosodiethylamine-induced liver injury rat model.

String scattering amplitudes and deformed cubic string field theory

Lai, Sheng-Hong,Lee, Jen-Chi,Lee, Taejin,Yang, Yi North-Holland Pub. Co 2018 Physics letters. Section B Vol.776 No.-

<P><B>Abstract</B></P> <P>We study string scattering amplitudes by using the deformed cubic string field theory which is equivalent to the string field theory in the proper-time gauge. The four-string scattering amplitudes with three tachyons and an arbitrary string state are calculated. The string field theory yields the string scattering amplitudes evaluated on the world sheet of string scattering whereas the conventional method, based on the first quantized theory brings us the string scattering amplitudes defined on the upper half plane. For the highest spin states, generated by the primary operators, both calculations are in perfect agreement. In this case, the string scattering amplitudes are invariant under the conformal transformation, which maps the string world sheet onto the upper half plane. If the external string states are general massive states, generated by non-primary field operators, we need to take into account carefully the conformal transformation between the world sheet and the upper half plane. We show by an explicit calculation that the string scattering amplitudes calculated by using the deformed cubic string field theory transform into those of the first quantized theory on the upper half plane by the conformal transformation, generated by the Schwarz–Christoffel mapping.</P>

Estimation of <i>C</i>(<i>t</i>) and the creep crack tip stress field of functionally graded materials and verification via finite element analysis

Lai, Huan Sheng,Yoon, Kee Bong Elsevier 2016 COMPOSITE STRUCTURES -BARKING THEN OXFORD- Vol.153 No.-

<P><B>Abstract</B></P> <P>Functionally graded materials (FGMs) are increasingly being used in high-temperature structural components. The time-dependent <I>C</I>-integral, <I>C</I>(<I>t</I>), is a significant parameter in characterizing the crack tip stress field from the small-scale to the extensive steady-state creep stages. In this paper, the creep crack behavior of FGMs with a crack parallel to the material property gradients was studied by using the finite element method. It was proven that <I>C</I>(<I>t</I>) remained valid for FGMs. An engineering method was proposed to estimate <I>C</I>(<I>t</I>) in the small scale and transition creep stages and estimate the crack tip stress field. Finite element results verified that the method could estimate <I>C</I>(<I>t</I>) in the small scale and transition creep stages and estimate the crack tip stress field. For cases with creep properties that increased in the crack growth direction, the effect of constraint on the estimated crack tip stress field had to be considered. The constraint parameter of <I>Q</I> was significantly affected by the creep property gradients. The method was independent of the gradient variation law of material properties.</P>

An Engineering Approach for Sustainable Peptide Synthesis

Sheng-Sheng Yu,Chen-Yu Chien,Chun-Wei Lai 한국고분자학회 2019 한국고분자학회 학술대회 연구논문 초록집 Vol.44 No.2

A Study on Proper Location of Welding Defect in Three Point Bend Testing with MDPE Pipe

Lai, Huan Sheng,Yoon, Kee Bong,Kil, Seong Hee The Korean Society for Energy 2015 에너지공학 Vol.24 No.1

Welding defects affect the performance of welded pipe joints. In this study, a three point bend test of welded steel and medium density polyethylene (MDPE) pipe joints with defects of various defect locations and defect materials was studied using the finite element method. The defect was assumed to be located at 12 o'clock, 3 o'clock or 6 o'clock direction. The results showed that pipes failed more easily on the compression side due to stress or local buckling. The air defect was more dangerous than the steel defect if the defect was located in the compression side; otherwise, the defect material effect on the integrity of pipes was ignorable. It is argued that the integrity of pipes with defects in the compression side is weaker than that in other regions, and the defect should be located in the compression side or the 12 o'clock position in the three point bend test to maximize the effect of defect existence on the pipe structural integrity.

A Study on Proper Location of Welding Defect in Three Point Bend Testing with MDPE Pipe

Huan Sheng Lai,Kee Bong Yoon,Seong Hee Kil 한국에너지학회 2015 에너지공학 Vol.24 No.1

Power Electronics for Household Appliance Revolution

Jih-Sheng (Jason) Lai 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

Effects of defect size on failure of butt fusion welded MDPE pipe under tension

Huan Sheng Lai,길성희,윤기봉 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.5

Since medium density polyethylene (MDPE) pipes are increasingly used in the gas industry, welding defects are becoming a safetyconcern. In this study, butt fusion welded MDPE pipe joints with spherical and planar defects of various sizes were studied by experimentaltensile tests and finite element analysis. These defects were considered for simulating lack of bonding during the welding. Thetensile test results showed that pipe strength was not reduced by defects that were up to 15% of the pipe’s thickness in size. On the otherhand, when the size of the defect was increased to 30% and 45% of the thickness, the failure strain decreased considerably. Finite elementanalysis verified that the effects of steel defects inserted intentionally before welding are comparable to those of air defects, whichare close to actual weld defect conditions. Hence, the experimental results obtained in this study can represent the actual situation. It isargued that a single welding defect with a maximum size smaller than 15% of the pipe’s thickness can be accepted without compromisingthe structural integrity of the pipe during short term of usage not considering long term creep or slow crack growth.

Effect of defects on the burst failure of butt fusion welded polyethylene pipes

Huan Sheng Lai,Nwe Ni Tun,Seong Hee Kil,윤기봉 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.5

With the increasing demand of Medium density polyethylene (MDPE) pipes for gas transmission, the safety concern related with welding defects is becoming a serious matter. In this paper, experimental burst tests and finite element analyses were employed to study butt fusion welded MDPE pipe joints with spherical and planar defects of various sizes. These defects were used to simulate lack of bonding during the welding. Test results showed that in all pipe test cases, the failure location originated from pipe substrates, even though the defect size was increased to 45% of the pipe’s wall thickness. The burst pressure could be estimated by the expression employed in the ASME BPVC, and in the burst pressure, the hoop stress was 20.28 MPa. Simulation results showed that the failure position was not only affected by the defect size, but also by the welding bead. It can be argued that a single welding defect whose maximum size is smaller than 15% of the thickness can be used without failure during short-term usage, even when there is no welding bead in the welded joint.

Metastatic Axillary Lymph Node Ratio (LNR) is Prognostically Superior to pN Staging in Patients with Breast Cancer -- Results for 804 Chinese Patients from a Single Institution

Xiao, Xiang-Sheng,Tang, Hai-Lin,Xie, Xin-Hua,Li, Lai-Sheng,Kong, Ya-Nan,Wu, Min-Qing,Yang, Lu,Gao, Jie,Wei, Wei-Dong,Xie, Xiaoming Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.9

The number of axillary lymph nodes involved and retrieved are important prognostic factors in breast cancer. The purpose of our study was to investigate whether the lymph node ratio (LNR) is a better prognostic factor in predicting disease-free survival (DFS) for breast cancer patients as compared with pN staging. The analysis was based on 804 breast cancer patients who had underwent axillary lymph node dissection between 1999 and 2008 in Sun Yat-Sen University Cancer Center. Optimal cutoff points of LNR were calculated using X-tile software and validated by bootstrapping. Patients were then divided into three groups (low-, intermediate-, and high-risk) according to the cutoff points. Predicting risk factors for relapse were performed according to Cox proportional hazards analysis. DFS was estimated using the Kaplan-Meier method and compared by the log-rank test. The 5-year DFS rate decreased significantly with increasing LNRs and pN. Univariate analysis found that the pT, pN, LNR, molecule type, HER2, pTNM stage and radiotherapy well classified patients with significantly different prognosis. By multivariate analysis, only LNR classification was retained as an independent prognostic factor. Furthermore, there was a significant prognostic difference among different LNR categories for pN2 category, but no apparent prognostic difference was seen between different pN categories in any LNR category. Therefore, LNR rather than pN staging is preferable in predicting DFS in node positive breast cancer patients, and routine clinical decision-making should take the LNR into consideration.