As bulk CMOS scaling is approaching the limit that is imposed by gate oxide tunneling, body doping, band-to-band tunneling, etc., non-classical MOSFET is becoming an intense subject of very large-scale integration (VLSI) research. Among a variety of non-classical MOSFETs, multiple-gate (MG) MOSFETs which are still based on Si have been proposed to scale down CMOS technology more aggressively because of better control of short-channel effects (SCEs), whereas novel MOSFETs utilizing III-V materials instead of Si are suggested to achieve CMOS performance breakthrough even without scaling down too aggressively due to the large mobility of mobile carriers. This dissertation focuses on the design and modeling of these two categories of non-classical MOSFETs. Actually, many different types of Si-based MG MOSFETs have been designed and even fabricated in the last two decades, including double-gate (DG) MOSFETs, surrounding-gate (SG) MOSFETs, quadruple-gate (QG) MOSFETs, triple-gate (TG) MOSFETs, Pi-gate MOSFETs, Omega-gate MOSFETs, and so on. Although the design work has been pretty much done, specific compact models for these MG MOSFETs other than BSIM, PSP, and HiSIM are in urgent need, because the charge sheet approximation is no longer appropriate for MG MOSFETs due to the so-called "volume inversion" effect. In this dissertation, we will first introduce the complete non-charge-sheet based analytic models of drain current, terminal charges and capacitance coefficients for long channel symmetric DG and SG MOSFETs. The DG and SG models will be generalized to a unified analytic drain current model for all kinds of MG MOSFETs, with some non-trivial yet reasonable approximations. Efforts will also be focused on making the physics-based model more versatile and computationally efficient. On the contrary, the research on III-V MOSFETs is still in the primary phase. Compact modeling for III-V MOSFETs is not being considered in the current stage because the device technology itself is far away from maturity, and the interest of this dissertation is in device design and basic physical modeling. With SCEs treated as the top-drawer consideration, a baseline device design of III-V MOSFET for sub-22nm scaling is proposed based on the thin-BOX-SOI -like structure. Physical modeling of capacitances in III- V MOSFETs has also been carried out to gain a more clear picture of capacitance degradation due to small density-of -states (DOS)

Osteoporosis is an age-related progressive bone disease. Recent advances in epigenetics, cell biology, osteoimmunology, and genetic epidemiology have unraveled new mechanisms and players underlying the pathology of osteoporosis, supporting a model of age-related dysregulation and crosstalk in the bone microenvironment.

Advanced age is a shared risk factor for many chronic and debilitating skeletal diseases including osteoporosis and periodontitis. Mesenchymal stem cells develop various aging phenotypes including the onset of senescence, intrinsic loss of regenerative potential and exacerbation of inflammatory microenvironment via secretory factors. This review elaborates on the emerging concepts on the molecular and epigenetic mechanisms of MSC senescence, such as the accumulation of oxidative stress, DNA damage and mitochondrial dysfunction. Senescent MSCs aggravate local inflammation, disrupt bone remodeling and bone-fat balance, thereby contributing to the progression of age-related bone diseases. Various rejuvenation strategies to target senescent MSCs could present a promising paradigm to restore skeletal aging.

This letter presents a novel cantilever and electrode biasing design of a metal-contact radio frequency microelectromechanical systems (RF-MEMS) switch to integrate multiple contact points in a single cantilever to improve the reliability of the switch. In the design presented in this letter, multiple contact points are integrated in a single cantilever. The contact points are used to conduct RF current one by one until one point fails. To switch between the contact points, two actuator electrodes are placed under the cantilever and biased with different voltages and the touching point between the cantilever and bottom RF electrode are changed. The parasitic capacitance of the switch is kept to be the same with that of a single contact point RF-MEMS switch. The OFF-state isolation will not be worsen, while accumulation of the lifetime of each contact point can improve the overall lifetime of the switch. Without the need of shrinking the actuator to maintain small parasitics capacitance, the contact force is also not sacrificed when comparing to the case of putting several miniature switches together. The performance and reliability improvement of the switch are experimentally demonstrated. The insertion losses of the switch of different contact points are <1 dB, and the isolation is better than 10 dB up to 20 GHz.

Dental-derived stem cells (DSCs) are attractive cell sources due to their easy access, superior growth capacity and low immunogenicity. They can respond to multiple extracellular matrix signals, which provide biophysical and biochemical cues to regulate the fate of residing cells. However, the direct transplantation of DSCs suffers from poor proliferation and differentiation toward functional cells and low survival rates due to local inflammation. Recently, elegant advances in the design of novel biomaterials have been made to give promise to the use of biomimetic biomaterials to regulate various cell behaviors, including proliferation, differentiation and migration. Biomaterials could be tailored with multiple functionalities, e.g., stimuli-responsiveness. There is an emerging need to summarize recent advances in engineered biomaterials-mediated delivery and therapy of DSCs and their potential applications. Herein, we outlined the design of biomaterials for supporting DSCs and the host response to the transplantation.

Mesenchymal stem cells (MSCs) have been identified and isolated from dental tissues, including stem cells from apical papilla, which demonstrated the ability to differentiate into dentin-forming odontoblasts. The histone demethylase KDM6B (also known as JMJD3) was shown to play a key role in promoting osteogenic commitment by removing epigenetic marks H3K27me3 from the promoters of osteogenic genes. Whether KDM6B is involved in odontogenic differentiation of dental MSCs, however, is not known. Here, we explored the role of KDM6B in dental MSC fate determination into the odontogenic lineage. Using shRNA-expressing lentivirus, we performed KDM6B knockdown in dental MSCs and observed that KDM6B depletion leads to a significant reduction in alkaline phosphate (ALP) activity and in formation of mineralized nodules assessed by Alizarin Red staining. Additionally, mRNA expression of odontogenic marker gene SP7 (osterix, OSX), as well as extracellular matrix genes BGLAP (osteoclacin, OCN) and SPP1 (osteopontin, OPN), was suppressed by KDM6B depletion. When KDM6B was overexpressed in KDM6B-knockdown MSCs, odontogenic differentiation was restored, further confirming the facilitating role of KDM6B in odontogenic commitment. Mechanistically, KDM6B was recruited to bone morphogenic protein 2 (BMP2) promoters and the subsequent removal of silencing H3K27me3 marks led to the activation of this odontogenic master transcription gene. Taken together, our results demonstrated the critical role of a histone demethylase in the epigenetic regulation of odontogenic differentiation of dental MSCs. KDM6B may present as a potential therapeutic target in the regeneration of tooth structures and the repair of craniofacial defects.

This paper presents a dielectric waveguide based multi-mode sub-THz interconnect channel for high data-rate high bandwidth-density planar chip-to-chip communications. By using a proposed new transition of microstrip line to dielectric waveguide, the interconnect channel achieves wide bandwidth on two orthogonal modes Ey11 and Ex11. To the authors' knowledge, this is the first demonstration of a multi-mode sub-THz interconnect channel. The measured minimum insertion losses for mode Ey11 and mode Ex11 are 8.0 dB with 21.3 GHz 3-dB bandwidth and 9.0 dB with 24.0 GHz 3-dB bandwidth, respectively.

Aging of craniofacial skeleton significantly impairs the repair and regeneration of trauma-induced bony defects, and complicates dental treatment outcomes. Age-related alveolar bone loss could be attributed to decreased progenitor pool through senescence, imbalance in bone metabolism and bone-fat ratio. Mesenchymal stem cells isolated from oral bones (OMSCs) have distinct lineage propensities and characteristics compared to MSCs from long bones, and are more suited for craniofacial regeneration. However, the effect of epigenetic modifications regulating OMSC differentiation and senescence in aging has not yet been investigated. In this study, we found that the histone demethylase KDM4B plays an essential role in regulating the osteogenesis of OMSCs and oral bone aging. Loss of KDM4B in OMSCs leads to inhibition of osteogenesis. Moreover, KDM4B loss promoted adipogenesis and OMSC senescence which further impairs bone-fat balance in the mandible. Together, our data suggest that KDM4B may underpin the molecular mechanisms of OMSC fate determination and alveolar bone homeostasis in skeletal aging, and present as a promising therapeutic target for addressing craniofacial skeletal defects associated with age-related deteriorations.