H. S. Huang

Tissue engineering-based cartilage repair with mesenchymal stem cells in a porcine model†‡

This in vivo pilot study explored the use of mesenchymal stem cell (MSC) containing tissue engineering constructs in repair of osteochondral defects. Osteochondral defects were created in the medial condyles of both knees of 16 miniature pigs. One joint received a cell/collagen tissue engineering construct with or without pretreatment with transforming growth factor β (TGF‐β) and the other joint from the same pig received no treatment or the gel scaffold only. Six months after surgery, in knees with no treatment, all defects showed contracted craters; in those treated with the gel scaffold alone, six showed a smooth gross surface, one a hypertrophic surface, and one a contracted crater; in those with undifferentiated MSCs, five defects had smooth, fully repaired surfaces or partially repaired surfaces, and one defect poor repair; in those with TGF‐β‐induced differentiated MSCs, seven defects had smooth, fully repaired surfaces or partially repaired surfaces, and three defects showed poor repair. In Pineda score grading, the group with undifferentiated MSC, but not the group with TGF‐β‐induced differentiated MSCs, had significantly lower subchondral, cell morphology, and total scores than the groups with no or gel‐only treatment. The compressive stiffness was larger in cartilage without surgical treatment than the treated area within each group. In conclusion, this preliminary pilot study suggests that using undifferentiated MSCs might be a better approach than using TGF‐β‐induced differentiated MSCs for in vivo tissue engineered treatment of osteochondral defects.

Conformational and adsorptive characteristics of albumin affect interfacial protein boundary lubrication: from experimental to molecular dynamics simulation approaches.

The lifetime of artificial joints is mainly determined by their biotribological properties. Synovial fluid which consists of various biological molecules acts as the lubricant. Among the compositions of synovial fluid, albumin is the most abundant protein. Under high load and low sliding speed articulation of artificial joint, it is believed the lubricants form protective layers on the sliding surfaces under the boundary lubrication mechanism. The protective molecular layer keeps two surfaces from direct collision and thus decreases the possibility of wear damage. However, the lubricating ability of the molecular layer may vary due to the conformational change of albumin in the process. In this study, we investigated the influence of albumin conformation on the adsorption behaviors on the articulating surfaces and discuss the relationship between adsorbed albumin and its tribological behaviors. We performed the friction tests to study the effects of albumin unfolding on the frictional behaviors. The novelty of this research is to further carry out molecular dynamics simulation, and protein adsorption experiments to investigate the mechanisms of the albumin-mediated boundary lubrication of arthroplastic materials. It was observed that the thermal processes induce the loss of secondary structure of albumin. The compactness of the unfolded structure leads to a higher adsorption rate onto the articulating material surface and results in the increase of friction coefficient.

Chondrocyte acting as phagocyte to internalize polyethylene wear particles and leads to the elevations of osteoarthritis associated NO and PGE2.

It remains a mystery about the role of chondrocyte or cartilage on the co-existence of ultra-high molecular weight polyethylene (UHMWPE) wear particles from partial joint arthroplasty. An inverted co-culture system was performed to investigate the interactions between chondrocytes and UHMWPE wear particles. It was first time observed that chondrocytes can engulf UHMWPE particles and release osteoarthritis associated pro-inflammatory factors. TEM observation and flow cytometric analysis demonstrated the phagocytosis of particles by chondrocytes. It was found that polyethylene particles may reduce the viability of chondrocytes, and enhance the secretion of nitric oxide (NO) and PGE(2). In conclusion, all these phenomena may contribute to further cartilage degeneration after partial joint arthroplasty surgery. It is first identified in this study that the chondrocyte acts as phagocyte to internalize wear particles and leads to the elevations of precursor mediators of osteoarthritis.

Visible Light Source Disturbing the Source/Drain Current of CLC Poly-Si n-TFT Device

CLC Poly-Si n-TFT Device M.C. Wang, Z.Y. Hsieh, C. Chen, J.M. Shieh, Y.T. Lin, H.S. Huang Institute of Mechatronic Engineering, National Taipei University of Technology, Taipei, 10601, Taiwan Department of Material Science & Engineering, National Chiao Tung University, Hsinchu 300, Taiwan National Nano Device Laboratories, Hsinchu 30078, Taiwan *Dept. of Electronic Engineering, Ming-Hsin University of Science and Technology; No. 1 Hsin-Hsing Road, Hsin-Fong, Hsin-Chu, 304, Taiwan; e-mail: mucwang@must.edu.tw.

Impact of stress induced by stressors on hot carrier reliability of strained nMOSFETs

In this study, the nMOSFETs with contact-etch-stop-layer (CESL) stressor and SiGe channel have been fabricated with a modified 90-nm technology. The performance of nMOSFETs and stress distribution in the channel region have been investigated. The hot carrier reliability of the SiGe-channeled nMOSFETs with various CESL nitride layers has also been extensively studied. In addition, the impact of stress induced by CESL stressor and SiGe-channel on hot-carrier reliability of the strained nMOSFETs has been analyzed through experimental measurements and stress simulation results.

Current conduction mechanisms of 0.65 nm equivalent oxide thickness HfZrLaO thin films

Metal-oxide-semiconductor (MOS) capacitors incorporating atomic-layer-deposited (ALD) LaO/HfZrO stacked gate dielectrics were fabricated. The experimental results reveal that the equivalent oxide thickness (EOT) is 0.65 nm, and the gate leakage current density (Jg) is only 1.9 A/cm2. The main current conduction mechanisms are Schottky emission, Poole-Frankel emission, and Fowler-Nordheim tunneling. The barrier height (ΦB) is estimated to be about 1.07 eV at TaC and HfZrLaO interface.

The influence of physical and electrical properties in HfO 2 thin film with different lanthanum doping position

In this paper, La-incorporated with HfO2 thin films increase crystallization temperature which of thin films is observed from X-ray diffraction (XRD). By nano-Auger analysis, the results show that the Hf atom out-diffusion into Si substrate is increased when the La dopant in the upper layer. The out-diffusion of Hf also affects the thickness of silicate. It is suggested to be the origin of leakage current. The physical and electrical properties of different positions of La were measured and compared in this work.

Interface Characterization of CeO2-Gated MOSFETs Using Gated Diode Method and Charge Pumping Technique

Metal-oxide-semiconductor field-effect transistors (MOSFETs) incorporating CeO2 dielectrics were fabricated and investigated. In this work, the interfacial and electrical properties of CeO2/Si were characterized by gated-diode method and charge pumping technique. The lowest density of interface traps per area and energy (Dit) of CeO2/Si interface in comparison with other high-k material is about 7.3×1010 cm-2-eV-1 due to the very low lattice mismatch at CeO2/Si interface. The density of interface trap per area (Nit) determined using gated diode method is 6×109 cm-2. The minority carrier lifetime (tFIJ), the effective capture cross section of surface state (αs) and surface recombination velocity (so) extracted using gated-diode method are 4.09×10-8 s, 7.14×10-14 cm2 and 4310 cm/s, respectively. Furthermore, a comparison with MOSFETs using the other high-k materials as gate dielectrics was also made.