Unusual Exchange Bias Effects Induced in NiFe/Mn Thin Films via Ion-beam Bombardment: Superlattice vs. Nanocomposite

Chi-Hsin Liu,Chin Shueh,Tien-Chi Lan,Ko-Wei Lin,Wen-Chen Chen,Te-Ho Wu,R. D. Desautels,J. van Lierop 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.12

The interplay between interlayer coupling and exchange bias coupling in [NiFe/Mn] multilayerbasedthin films was investigated by using ion-beam bombardment during deposition to control theconfigurations from superlattice to nanocomposite or hybrid-structured thin films. Results showedthat well-defined interfaces in the superlattice [NiFe/Mn] thin film exhibited an interlayer couplingbehavior. In contrast, an enhanced coercivity was observed in the nanocomposite [NiFe-Mn] thinfilm. However, the hybrid [NiFe-Mn]/[NiFe/Mn] thin film with an intermixed NiFeMn alloyed filmcomponent gave rise to unusual positive exchange bias coupling.

Adjuvant Radiotherapy after Breast Conserving Treatment for Breast Cancer:A Dosimetric Comparison between Volumetric Modulated Arc Therapy and Intensity Modulated Radiotherapy

Liu, Zhe-Ming,Ge, Xiao-Lin,Chen, Jia-Yan,Wang, Pei-Pei,Zhang, Chi,Yang, Xi,Zhu, Hong-Cheng,Liu, Jia,Qin, Qin,Xu, Li-Ping,Lu, Jing,Zhan, Liang-Liang,Cheng, Hong-Yan,Sun, Xin-Chen Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.8

Background: Radiotherapy is an important treatment of choice for breast cancer patients after breast-conserving surgery, and we compare the feasibility of using dual arc volumetric modulated arc therapy (VMAT2), single arc volumetric modulated arc therapy (VMAT1) and Multi-beam Intensity Modulated Radiotherapy (M-IMRT) on patients after breast-conserving surgery. Materials and Methods: Thirty patients with breast cancer (half right-sided and half left-sided) treated by conservative lumpectomy and requiring whole breast radiotherapy with tumor bed boost were planned with three different radiotherapy techniques: 1) VMAT1; 2) VMAT2; 3) M-IMRT. The distributions for the planning target volume (PTV) and organs at risk (OARs) were compared. Dosimetries for all the techniques were compared. Results: All three techniques satisfied the dose constraint well. VMAT2 showed no obvious difference in the homogeneity index (HI) and conformity index (CI) of the PTV with respect to M-IMRT and VMAT1. VMAT2 clearly improved the treatment efficiency and can also decrease the mean dose and V5Gy of the contralateral lung. The mean dose and maximum dose of the spinal cord and contralateral breast were lower for VMAT2 than the other two techniques. The very low dose distribution (V1Gy) of the contralateral breast also showed great reduction in VMAT2 compared with the other two techniques. For the ipsilateral lung of right-sided breast cancer, the mean dose was decreased significantly in VMAT2 compared with VMAT1 and M-IMRT. The V20Gy and V30Gy of the ipsilateral lung of the left-sided breast cancer for VMAT2 showed obvious reduction compared with the other two techniques. The heart statistics of VMAT2 also decreased considerably compared to VMAT1 and M-IMRT. Conclusions: Compared to the other two techniques, the dual arc volumetric modulated arc therapy technique reduced radiation dose exposure to the organs at risk and maintained a reasonable target dose distribution.

Occupational Neurotoxic Diseases in Taiwan

Liu, Chi-Hung,Huang, Chu-Yun,Huang, Chin-Chang Occupational Safety and Health Research Institute 2012 Safety and health at work Vol.3 No.4

Occupational neurotoxic diseases have become increasingly common in Taiwan due to industrialization. Over the past 40 years, Taiwan has transformed from an agricultural society to an industrial society. The most common neurotoxic diseases also changed from organophosphate poisoning to heavy metal intoxication, and then to organic solvent and semiconductor agent poisoning. The nervous system is particularly vulnerable to toxic agents because of its high metabolic rate. Neurological manifestations may be transient or permanent, and may range from cognitive dysfunction, cerebellar ataxia, Parkinsonism, sensorimotor neuropathy and autonomic dysfunction to neuromuscular junction disorders. This study attempts to provide a review of the major outbreaks of occupational neurotoxins from 1968 to 2012. A total of 16 occupational neurotoxins, including organophosphates, toxic gases, heavy metals, organic solvents, and other toxic chemicals, were reviewed. Peer-reviewed articles related to the electrophysiology, neuroimaging, treatment and long-term follow up of these neurotoxic diseases were also obtained. The heavy metals involved consisted of lead, manganese, organic tin, mercury, arsenic, and thallium. The organic solvents included n-hexane, toluene, mixed solvents and carbon disulfide. Toxic gases such as carbon monoxide, and hydrogen sulfide were also included, along with toxic chemicals including polychlorinated biphenyls, tetramethylammonium hydroxide, organophosphates, and dimethylamine borane. In addition we attempted to correlate these events to the timeline of industrial development in Taiwan. By researching this topic, the hope is that it may help other developing countries to improve industrial hygiene and promote occupational safety and health care during the process of industrialization.

Fenofibrate Increases Radiosensitivity in Head and Neck Squamous Cell Carcinoma via Inducing G2/M Arrest and Apoptosis

Liu, Jia,Ge, Yang-Yang,Zhu, Hong-Cheng,Yang, Xi,Cai, Jing,Zhang, Chi,Lu, Jing,Zhan, Liang-Liang,Qin, Qin,Yang, Yan,Yang, Yue-Hua,Zhang, Hao,Chen, Xiao-Chen,Liu, Zhe-Ming,Ma, Jian-Xin,Cheng, Hong-Yan,S Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.16

Radiation therapy is an important treatment for head and neck squamous cell carcinoma (HNSCC). However, how to promote radiation sensitivity in HNSCC remains a challenge. This study aimed to investigate the radiosensitizing effects of fenofibrate on HNSCC and explore the underlying mechanisms. HNSCC cell lines CNE-2 and KB were subjected to ionizing radiation (IR), in the presence or absence of fenofibrate treatment. Cell growth and survival, apoptosis and cell cycle were evaluated. In addition, CNE-2 cells were xenografted into nude mice and subjected to IR and/or fenofibrate treatment. The expression of cyclinB and CDK1 was detected by Western blotting. Our results showed that fenofibrate efficiently radiosensitized HNSCC cells and xenografts in mice, and induced apoptosis and G2/M arrest via reducing the activity of the CDK1/cyclinB1 kinase complex. These data suggest that fenofibrate could be a promising radiosensitizer for HNSCC radiotherapy.

Challenges and opportunities in the engineering of intelligent systems

Liu, Shi-Chi,Tomizuka, Masayoshi,Ulsoy, A. Galip Techno-Press 2005 Smart Structures and Systems, An International Jou Vol.1 No.1

This paper describes the area of intelligent systems research as funded by the Civil and Mechanical Systems (CMS) Division of the National Science Foundation (NSF). With developments in computer science, information technology, sensing and control the design of typical machines and structures by civil and mechanical engineers is evolving toward intelligent systems that can sense, decide and act. This trend toward electro-mechanical design is well-established in modern machines (e.g. vehicles, robots, disk drives) and often referred to as mechatronics. More recently intelligent systems design is becoming an important aspect of structures, such as buildings and bridges. We briefly review recent developments in structural control, including the role that NSF has played in their development, and discuss on-going CMS activities in this area. In particular, we highlight the interdisciplinary initiative on Sensors and Sensor Networks and the Network for Earthquake Engineering Simulation (NEES). NEES is a distributed cyberinfrastructure to support earthquake engineering research, and provides the pioneering NEES grid computing environment for simulation, teleoperation, data collection and archiving, etc.

Boussinesq equations for internal waves in a two-fluid system with a rigid lid

Liu, Chi-Min Techno-Press 2016 Ocean systems engineering Vol.6 No.1

A theoretical study of Boussinesq equations (BEs) for internal waves propagating in a two-fluid system is presented in this paper. The two-fluid system is assumed to be bounded by two rigid plates. A set of three equations is firstly derived which has three main unknowns, the interfacial displacement and two velocity potentials at arbitrary elevations for upper and lower fluids, respectively. The determination of the optimal BEs requires a solution of depth parameters which can be uniquely solved by applying the $Pad{\acute{e}}$ approximation to dispersion relation. Some wave properties predicted by the optimal BEs are examined. The optimal model not only increases the applicable range of traditional BEs but also provides a novel aspect of internal wave studies.

A nonNMDA antagonist, GYKI 52466 improves microscopic O₂balance in the cortex during focal cerebral ischemia

Chi, Oak Z.,Chang, Qiang,Wang, Guolin,Liu, Xia,Harvey R. Weiss 경희대학교 동서의학연구소 1999 INTERNATIONAL SYMPOSIUM ON EAST-WEST MEDICINE Vol.1999 No.1

Oak Z.Chi,Qiang Chang, Guolin Wang*, Xia Liu, Harvey R. Weiss□.Deprtments of Anesthesai, Departments of Physiology and Biophysics, University of Medicne and Dentisrty of New Jersey,Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA and*Department of Anesthesia, Medical University, Tianjing, People's Republic of China. A non-NMDA antagonist, GYKI 52466 improves microscopic O² balance in the cortex during focal cerebral ischemia. Proceedings of International Symposium on East-West Medicine, Seoul. 172-182, 1999.-This study was performed to test whether GYKI 52466, a non-NMDA receptor antagonist, would improve microregional oxygen supply and consumption balance in the focal cerebral ischemic area. Rats were anesthetized with 1.4% isoflurance. For the GYKI Group (n=8), 19 min before middle cerebral artery (MCA) occlusion, a bolus of 5mg/kg of GYKI 52466 iv was administered and was followed by an infusion of 5mg/kg/hr. For the control Group(n=8), the same volume of the vehicle was administered. One hour after MCA occlusion, regional cerebral blood flow (rCBF) was measured using the 14C-iodoantipyrine autoradiographic technique. Microscopic arterial and venous oxygen saturations were determined using microspectrophotometry. In the cortex contralateral to MCA occlusion, the average rCBF and the average O² consumption were lower in the GYKI Group than in the Control Group (rCBF:GYKI 65.5±24.1, Control 97.7 33.4ml/100g/min;O² consumption: GYKI3.9±1.2, Control 6.2±2.5ml O²/100g/min) without a significant difference in the number of veins with SvO²<50%. In the ischemic cortex, the number of veins with SvO²<50% was significantly smaller in the GYKI Group (21 veins out of 63)than in the Control Group(45 out of 59)without a significant difference in the average rCBF(GYKI44.9±17.7, Control 29.7±10.4) or regional O² consumption between these two groups (GYKI 3.3±1.4,Control 27.7±1.2). Our data demonstrated that GYKI 52466 was effective in improving microscopic O² balance in the focal ischemic cortical area of the brain and it decreased O² consumption in the non-ischemic cortex. [Neurological Research 1999;21:299-304]

Extracellular Vesicles Carrying RUNX3 Promote Differentiation of Dental Pulp Stem Cells

Chi Yuhong,Liu Tingzhong,Jin Qingsong,Liu Hao 한국조직공학과 재생의학회 2024 조직공학과 재생의학 Vol.21 No.1

Background: This study aims to clarify the mechanism underlying dental pulp cells-extracellular vesicles (DPC–EVs) carrying runt-related transcription factor 3 (RUNX3) in mediating odontogenic differentiation of dental pulp stem cells (DPSCs) with the involvement of miR-30a-5p-regulated NOTCH1. Methods: Extracellular vesicles (EVs) were isolated from human DPSCs, and identified using transmission electron microscopy, and nanoparticle tracking analysis. PBS, EVs, or EV inhibitor GW4869 was added to DPSCs for co-culture, whilst odontogenic differentiation was assessed in terms of ratio of mineralized nodules and expression odontoblast differentiation markers. Dual luciferase reporter gene assay and chromatin immunoprecipitation for binding relation among RUNX3, miR-30a-5p and NOTCH1were employed to evaluate their roles in odontogenic differentiation was determined. Animal experiment was established to confirm the effect of DPC-EVs-loaded RUNX3 on dental pulp. Results: In vitro finding demonstrated that EVs delivered RUNX3 to DPSCs, thereby activated miR-30a-5p expression and inhibited NOTCH1 expression, which was reversed by addition of GW4869. RUNX3 upregulation promoted miR-30a-5p while miR-30a-5p targeted and inhibited NOTCH1. Silencing of RUNX3 in EVs decreased expression of those differentiation markers, downregulated miR-30a-5p and upregulated NOTCH1. Conclusion: DPSC-EVs can carry RUNX3 to the DPSCs, promote the transcription of miR-30a-5p, and then inhibit the expression of NOTCH1, and finally promote the odontogenic differentiation of DPSCs. Background: This study aims to clarify the mechanism underlying dental pulp cells-extracellular vesicles (DPC–EVs) carrying runt-related transcription factor 3 (RUNX3) in mediating odontogenic differentiation of dental pulp stem cells (DPSCs) with the involvement of miR-30a-5p-regulated NOTCH1. Methods: Extracellular vesicles (EVs) were isolated from human DPSCs, and identified using transmission electron microscopy, and nanoparticle tracking analysis. PBS, EVs, or EV inhibitor GW4869 was added to DPSCs for co-culture, whilst odontogenic differentiation was assessed in terms of ratio of mineralized nodules and expression odontoblast differentiation markers. Dual luciferase reporter gene assay and chromatin immunoprecipitation for binding relation among RUNX3, miR-30a-5p and NOTCH1were employed to evaluate their roles in odontogenic differentiation was determined. Animal experiment was established to confirm the effect of DPC-EVs-loaded RUNX3 on dental pulp. Results: In vitro finding demonstrated that EVs delivered RUNX3 to DPSCs, thereby activated miR-30a-5p expression and inhibited NOTCH1 expression, which was reversed by addition of GW4869. RUNX3 upregulation promoted miR-30a-5p while miR-30a-5p targeted and inhibited NOTCH1. Silencing of RUNX3 in EVs decreased expression of those differentiation markers, downregulated miR-30a-5p and upregulated NOTCH1. Conclusion: DPSC-EVs can carry RUNX3 to the DPSCs, promote the transcription of miR-30a-5p, and then inhibit the expression of NOTCH1, and finally promote the odontogenic differentiation of DPSCs.

Investigation of Multiscale Failure Mechanism of Red Bed Soft Rock using Grain-Based Finite-Discrete Element Method Combined with X-Ray Micro-computerized Tomography

Chi Liu,Xiaoli Liu,Chunlu Wu,Enzhi Wang,Sijing Wang,Haoyang Peng 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.3

The mechanical properties and failure mechanisms of geomaterials are greatly affected by their heterogeneity. As a special complex rock medium, the mechanical response of red bed soft rock is of considerable importance in stability analyses and the protection of slopes. In this study, X-ray micro-computerized tomography (micro-CT) was used to obtain the spatial distribution of minerals in red bed soft rock. An image processing procedure was proposed to incorporate the extracted mesoscopic mineral and crack distribution into the model of the grain-based finite-discrete element method (GB-FDEM). Subsequently, a uniaxial compression test and Brazilian disc splitting test were performed to obtain the mechanical response and failure modes of mudstone. The microscopic fracture morphology and traces of intragranular and intergranular cracks under tensile and shear stress were analyzed in detail. The numerical results show that the GB-FDEM model successfully characterized the mechanical response, which was similar to that of the laboratory tests and the traditional homogeneous models. The presence of minerals and pre-existing cracks disturbed the stress distribution in the heterogeneous model, which resulted in a difference in local stress that reasonably explained the phenomenon of local fragmentation. The simulated macroscopic failure mode of the heterogeneous models was most consistent with the results of the laboratory tests. The systematic framework proposed in this study provides a powerful tool for further understanding the multiscale (micro, meso, and macro) failure mechanism of red bed soft rock and predicting a realistic fracture process while reducing the tedious and redundant laboratory tests.

Enhanced x-ray irradiation-induced cancer cell damage by gold nanoparticles treated by a new synthesis method of polyethylene glycol modification

Liu, Chi-Jen,Wang, Chang-Hai,Chien, Chia-Chi,Yang, Tsung-Yeh,Chen, Shin-Tai,Leng, Wei-Hua,Lee, Cheng-Feng,Lee, Kuen-Ho,Hwu, Y,Lee, Yao-Chang,Cheng, Chia-Liang,Yang, Chung-Shi,Chen, Y J,Je, J H,Margari IOP Pub 2008 Nanotechnology Vol.19 No.29

<P>We explored a very interesting gold nanoparticle system—pegylated gold in colloidal solution—and analyzed its uptake by mice colorectal adenocarcinoma CT26 tumor cells and the impact on the cell’s response to x-ray irradiation. We found that exposure to polyethylene glycol (PEG) modified (‘pegylated’) 4.7 ± 2.6 nm gold nanoparticles synthesized by a novel synchrotron-based method enhances the response of CT26 cells to x-ray irradiation. Transmission electron microscopy (TEM) and confocal microscopy revealed that substantial amounts of such nanoparticles are taken up and absorbed by the cells and this conclusion is supported by quantitative induced coupled plasma (ICP) results. Standard tests indicated that the internalized particles are highly biocompatible but strongly enhance the cell damage induced by x-ray irradiation. Synchrotron radiation Fourier transform infrared (SR-FTIR) spectromicroscopy analyzed the chemical aspects of this phenomenon: the appearance of C = O stretching bond spectral features could be used as a marker for cell damage and confirmed the enhancement of the radiation-induced toxicity for cells.</P>