Growth and characterization of gallium arsenide on silicon-on-sapphire and silicon

A study has been conducted to investigate and compare the growth, strain, defects, electrical and optical properties of GaAs layers grown simultaneously on silicon-on-sapphire (SOS) and Si substrates using a two-step metalorganic chemical vapor deposition (MOCVD) growth procedure. A variety of techniques have been used to characterize and investigate the different properties of these two layers. Among them, x-ray diffraction was used to determine the lattice dimensions and thereby the sign of residual strain, x-ray rocking procedures to measure the strain and crystallinity, and variable temperature x-ray diffraction to investigate the temperature dependence of residual strain. Scanning electron microscopy (SEM) was used to examine the surface morphology. Transmission electron microscopy (TEM) was used to observe the microstructure and defect distribution as well as defect density. Also secondary ion mass spectroscopy (SIMS) was used to study the cross-diffusion from substrates. In addition, capacitance-voltage (C-V) measurements and Hall-effect measurements were used to determine the carrier concentration and mobility. Finally, photoluminescence (PL) was used to observe the low-temperature optical response of GaAs layers. The results of these investigations of GaAs on SOS and Si substrates are compared as a function of the thickness of GaAs layers. Finally, the effects of residual strain, presence of defects and cross-diffusion of Si on electrical and optical properties of GaAs layers are discussed.U of I OnlyETDs are only available to UIUC Users without author permissio

Lessons learned from dengue: Focus on Taiwan

This chapter outlines the current views on dengue disease, epidemiology, treatment and prevention worldwide and with a focus on the Taiwan experience. Geographical differences in virus spread and in clinical profiles are revealed, as well as ongoing research efforts towards a safe and effective dengue vaccine

Negative regulation of type I interferon signaling by integrin-linked kinase permits dengue virus replication.

Dengue virus (DENV) infection can induce life-threatening dengue hemorrhagic fever/dengue shock syndrome in infected patients. DENV is a threat to global health due to its growing numbers and incidence of infection in the last 50 years. During infection, DENV expresses ten structural and nonstructural proteins modulating cell responses to benefit viral replication. However, the lack of knowledge regarding the cellular proteins and their functions in enhancing DENV pathogenesis impedes the development of antiviral drugs and therapies against fatal DENV infection. Here, we identified that integrin-linked kinase (ILK) is a novel enhancing factor for DENV infection by suppressing type I interferon (IFN) responses. Mechanistically, ILK binds DENV NS1 and NS3, activates Akt and Erk, and induces NF-κB-driven suppressor of cytokine signaling 3 (SOCS3) expression. Elevated SOCS3 in DENV-infected cells inhibits phosphorylation of STAT1/2 and expression of interferon-stimulated genes (ISGs). Inhibiting ILK, Akt, or Erk activation abrogates SOCS3 expression. In DENV-infected mice, the treatment of an ILK inhibitor significantly reduces viral loads in the brains, disease severity, and mortality rate. Collectively, our results show that ILK is a potential therapeutic target against DENV infection

Molecular-Clinical Correlation in Pediatric Medulloblastoma: A Cohort Series Study of 52 Cases in Taiwan.

In 2016, a project was initiated in Taiwan to adopt molecular diagnosis of childhood medulloblastoma (MB). In this study, we aimed to identify a molecular-clinical correlation and somatic mutation for exploring risk-adapted treatment, drug targets, and potential genetic predisposition. In total, 52 frozen tumor tissues of childhood MBs were collected. RNA sequencing (RNA-Seq) and DNA methylation array data were generated. Molecular subgrouping and clinical correlation analysis were performed. An adjusted Heidelberg risk stratification scheme was defined for updated clinical risk stratification. We selected 51 genes for somatic variant calling using RNA-Seq data. Relevant clinical findings were defined. Potential drug targets and genetic predispositions were explored. Four core molecular subgroups (WNT, SHH, Group 3, and Group 4) were identified. Genetic backgrounds of metastasis at diagnosis and extent of tumor resection were observed. The adjusted Heidelberg scheme showed its applicability. Potential drug targets were detected in the pathways of DNA damage response. Among the 10 patients with SHH MBs analyzed using whole exome sequencing studies, five patients exhibited potential genetic predispositions and four patients had relevant germline mutations. The findings of this study provide valuable information for updated risk adapted treatment and personalized care of childhood MBs in our cohort series and in Taiwan