36 research outputs found
Susceptibility Characterization of a Cavity with an Aperture by using Slowly Rotating EM Fields: FDTD Analysis and Measurements
This paper describes the evaluation of the susceptibility of a cavity with an aperture using the finite-difference time-domain (FDTD) method and experimentally. To reduce the computing time, the FDTD method is used for the radiation from the cavity and the susceptibility is obtained by using the reciprocity theorem. The cavity used here is modeled after a full-tower desktop enclosure with a 3.5-in bay. The susceptibility characteristics are evaluated by measuring outputs of a monopole antenna and transmission lines installed in the cavity. The susceptibility characteristics, using a three-dimensional (3-D) map, are studied from the computed and the measured results by applying slowly rotating electromagnetic fields to the cavity on a turntable. Measured and modeled results are in good agreement, indicating the merits of the proposed approach for susceptibility/immunity evaluation. Moreover, some discussions are made to check the susceptibility mechanism
Modeling Noise Coupling from Non-Parallel PCB Trace Routing
Coupling between PCB signal traces in proximity is of concern to PCB designers and EMC engineers. The behavior of noise coupling between non-parallel microstrip lines is studied in this paper by a full-wave numerical modeling method CEMPIE, designating a circuit extraction approach based on a mixed-potential integral equation formulation. Good agreement between the numerical results and measurements was obtained
Extracting CAD Models for Quantifying Noise Coupling Between Vias in PCB Layouts
A method to extract a lumped element prototype SPICE model is used to study noise coupling between non-parallel traces on a PCB. The parameters in this model are extracted using a PEEC-like approach, a Circuit Extraction approach based on a Mixed-Potential Integral Equation formulation (CEMPIE). Without large numbers of unknowns, the SPICE model saves computation time. Also, it is easy to incorporate into system SPICE net list to acquire the system simulation result considering the coupling between traces on the printed circuit board (PCB). A representative case is studied, and the comparison of measurements, CEMPIE simulation, and SPICE modeling are given
Identification of TRIM14 as a Type I IFN-Stimulated Gene Controlling Hepatitis B Virus Replication by Targeting HBx
Hepatitis B virus (HBV) remains a major cause of hepatic disease that threatens human health worldwide. Type I IFN (IFN-I) therapy is an important therapeutic option for HBV patients. The antiviral effect of IFN is mainly mediated via upregulation of the expressions of the downstream IFN-stimulated genes. However, the mechanisms by which IFN induces ISG production and inhibits HBV replication are yet to be clarified. TRIM14 was recently reported as a key molecule in the IFN-signaling pathway that regulates IFN production in response to viral infection. In this study, we sought to understand the mechanisms by which IFN restricts HBV replication. We confirmed that TRIM14 is an ISG in the hepatic cells, and that the pattern-recognition receptor ligands polyI:C and polydAdT induce TRIM14 dependent on IFN-I production. In addition, IFN-I-activated STAT1 (but not STAT3) directly bound to the TRIM14 promoter and mediated the induction of TRIM14. Interestingly, TRIM14 played an important role in IFN-I-mediated inhibition of HBV, and the TRIM14 SPRY domain interacted with the C-terminal of HBx, which might block the role of HBx in facilitating HBV replication by inhibiting the formation of the Smc-HBx–DDB1 complex. Thus, our study clearly demonstrates that TRIM14 is a STAT1-dependent ISG, and that the IFN-I–TRIM14–HBx axis shows an alternative way to understand the mechanism by which IFN-I inhibits virus replication
Type-I-IFN-Stimulated Gene TRIM5Îł Inhibits HBV Replication by Promoting HBx Degradation
To understand the molecular mechanisms that
mediate the anti-hepatitis B virus (HBV) effect
of interferon (IFN) therapy, we conduct highthroughput
bimolecular fluorescence complementation
screening to identify potential physical
interactions between the HBx protein and 145 IFNstimulated
genes (ISGs). Seven HBx-interacting
ISGs have consistent and significant inhibitory effects
on HBV replication, among which TRIM5g suppresses
HBV replication by promoting K48-linked
ubiquitination and degradation of the HBx protein
on the K95 ubiquitin site. The B-Box domain of
TRIM5g under overexpression conditions is sufficient
to trigger HBx degradation and is responsible
both for interacting with HBx and recruiting
TRIM31, which is an ubiquitin ligase that triggers
HBx ubiquitination. High expression levels of
TRIM5g in IFN-a-treated HBV patients might indicate
a better therapeutic effect. Thus, our studies identify
a crucial role for TRIM5g and TRIM31 in promoting
HBx degradation, which may facilitate the development
of therapeutic agents for the treatment of patients
with IFN-resistant HBV infection
A high-throughput platform for stem cell niche co-cultures and downstream gene expression analysis
Stem cells reside in 'niches', where support cells provide critical signalling for tissue renewal. Culture methods mimic niche conditions and support the growth of stem cells in vitro. However, current functional assays preclude statistically meaningful studies of clonal stem cells, stem cell-niche interactions, and genetic analysis of single cells and their organoid progeny. Here, we describe a 'microraft array' (MRA) that facilitates high-throughput clonogenic culture and computational identification of single intestinal stem cells (ISCs) and niche cells. We use MRAs to demonstrate that Paneth cells, a known ISC niche component, enhance organoid formation in a contact-dependent manner. MRAs facilitate retrieval of early enteroids for quantitative PCR to correlate functional properties, such as enteroid morphology, with differences in gene expression. MRAs have broad applicability to assaying stem cell-niche interactions and organoid development, and serve as a high-throughput culture platform to interrogate gene expression at early stages of stem cell fate choices
Noise Coupling from Single-Ended or Differential Signaling to Nearby Power Trace
Abstract Power and ground planes in the multilayer printed circuit board exhibits resonance in the frequency domain. Replacing the power supply planes by traces can considerably reduce the noise in the reference or ground, which leads to a dramatic reduction of the radiated electromagnetic fields. The power trace, however, may be coupled by nearby single-ended or differential signaling. The noise coupling from a single-ended or differential signaling to a nearby power trace is investigated in this work. First, the telegrapher's equations for multiconductor lines are applied. The analysis of the noise coupling is obtained by solving the telegrapher's equations using the mode decomposition technique. The results will be used as guidelines in the future interconnect design