MOLECULAR AND GENOMIC APPROACHES TO UNDERSTANDING HOST-VIRUS INTERACTIONS IN SHAPING THE OUTCOME OF EQUINE ARTERITIS VIRUS INFECTION

Equine arteritis virus (EAV) is the causal agent of equine viral arteritis, a disease of equids. During natural outbreaks of the disease, EAV can cause abortion in pregnant mares and persistent infection in stallions. Understanding how host cellular proteins interact with viral RNA and viral proteins, as well as their role in viral infection, will enable better characterization of the pathogenesis of EAV and establishment of persistent infection in stallions. Accordingly, we hypothesized that both viral factors and host genetically related factors could influence the outcome of EAV infection in horses. To test this hypothesis, we first combined contemporary molecular biology techniques with dual color flow cytometric analysis to characterize the interactions of viral structural proteins and the equine peripheral blood mononuclear cells in vitro. Results from this study demonstrated that interactions between GP2, GP3, GP4, GP5 and M envelope proteins of EAV play a major role in determining the CD14+ monocyte tropism while the tropism of CD3+ T lymphocytes is determined by GP2, GP4, GP5 and M envelope proteins but not the GP3 protein. Secondly, a genome wide association study using SNP genotyping identified a common haplotype associated with the in vitro CD3+ T lymphocyte/resistance to EAV infection among four breeds of horses. Subsequently, these studies were extended to establish a possible correlation between the in vitro susceptibility of CD3+ T lymphocytes to EAV and establishment of persistent infection in stallions. Interestingly, carrier stallions with susceptible CD3+ T lymphocyte phenotype to EAV may represent those at higher risk of becoming persistently infected. Finally, the precise effect of EAV on the immune system of horses, innate and humoral immunity, was studied. Horses were shown to mount a strong humoral antibody response to nonstructural proteins (nsps) 2, 4, 5 and 12 of EAV, whereas nsps 1, 2 and 11 suppressed the type I interferon production. The data presented in this dissertation suggest new directions for future EAV research using genomic and proteomic approaches to study host cell factors involved in EAV attachment and entry and establishment of persistent infection in the stallions

New Kid on the Block: Double-Peak Strain Pattern in Arrhythmic Mitral Valve Prolapse.

peer reviewe

Atrial Secondary Mitral Regurgitation: Often Overlooked, But Never Forgotten.

peer reviewe

Optical Packet Switching Contention Resolution Based On A Hybrid Wavelength Conversion-Fiber Delay Line Scheme

Due to the convergence of computer communication and telecommunication technology, data traffic exceeds the telephony traffic. Thus, existing connection oriented and circuit switched network will need to be upgraded toward optical packet switched network. Optical packet switching has characteristics like high speed, data rate/data format transparency and configurable. Wavelength Division Multiplexing is the technology of combining a number of wavelengths in a single fiber. It is a tremendous trend to harness larger bandwidth for enormous delivery. WDM optical devices for multiplexing and switching in simple configuration are now available at a reasonable cost. It is a very appealing solution for development of optical packet switching. The issue of contention arises when two or more packets contend for the same output port in a switch with the same wavelength, which results to packet loss. The packet loss probability is addressed as the most inevitable and significant measurable performance parameter with QoS provisioning that is dominated by wavelength contention in optical packet switches. In electronic domain packet switched network, the contention is resolved by store and forward technique using the available electronic random access memory (RAM). Due to the immaturity of optical memory storage technology, there is no available ready-to-use optical random access memory. In order to overcome this bottleneck, several approaches have been adopted to resolve the contention problem from three domains: time, space and wavelength as stated: fiber delay line (time), deflection routing (space) and wavelength conversion (wavelength). Consequently, contention resolution in wavelength domain has attracted considerable interest among the optical communications community instead of implementing optical buffering and deflection routing that have been studied previously. This thesis proposes a bufferless, single stage, non-blocking fully connected optical packet switch for synchronous optical packet switching network, followed by a prioritized scheduling algorithm in association with hybrid contention resolution schemes. This iterative prioritized scheduling comprises of a set of preemptive selective policies for contention resolution. It is a hybrid technique that integrates wavelength conversion with feedback mechanism realized by fiber delay lines (FDL). By means of simulation, the proposed scheme has been investigated and compared with the conventional baseline scheme. A sensitive description of the satisfied packet loss probability and average packet delay as a function of main design parameters such as switch size, number of wavelengths, traffic load, degree of conversion and number of fiber delay lines have been carried out with significant improvement.Simulation results proved that the proposed scheme is an efficient approach in resolving packet contention with less complexity in execution. Relatively, number of wavelength, traffic load and degree of conversion has significant impact to packet loss ratio. The implementation of fiber delay lines results on average packet delay. Simulation results demonstrated that the switch size mildly affect the performance parameter. Respectively, packet loss ratio below 10-10 is obtained via simulation by the means of wavelength conversion without conventional buffering delay. The packet loss ratio is further reduced with the method as aforementioned with the insertion of fiber delay lines where PLR below 10-13 is achieved, which is much lower than the benchmark value. Furthermore, the obtained simulation results show that by classifying packet priority, the proposed scheduling scheme and architecture are able to offer differentiated class of service

Stress imaging versus fractional flow reserve: what comes first-the chicken or the egg?

peer reviewe

Is Malaysia ready for sustainable energy? Exploring the attitudes toward solar energy and energy behaviors in Malaysia

To meet the larger demand for electricity supply, Malaysia needs to achieve two main psychosocial conditions, among others—having the awareness of renewable energy and demonstrating energy-conserving behavior. To examine whether Malaysia has met these two conditions, we recruited 225 participants (n = 109 women, n = 113 men, n = 3 did not indicate) to complete a series of questionnaires. The results showed that the public was aware of the option of solar energy but was not ready to install solar photovoltaic panels after being told the cost incurred. Furthermore, the public did not show satisfying energy-conserving behaviors. To boost the installation of solar power, increasing the public’s energy knowledge and implementing policies to reduce the installation cost might be helpful. These findings highlighted Malaysia’s low readiness for solar power and shed some light on what needs to be done to be better prepared for solar power

Psychosocial implications of large-scale implementations of solar power in Malaysia

The present study aimed to investigate the psychosocial impacts of large-scale solar (LSS) power projects. There were 225 participants (n = 109 women, n = 3 did not indicate gender) participated in our study by completing a series of questionnaires. We found that participants who lived farther from the LSS power project location and those who viewed the project as being impactful were optimistic about the benefits LSS power projects could bring. Our participants also demonstrated support for renewable energy development in Malaysia. These findings may provide important implications for the implementation and execution of LSS power projects and policies

The Conundrum of Tricuspid Regurgitation Grading

Findings from early percutaneous tricuspid intervention trials have shown that the severity of tricuspid regurgitation (TR) far exceeded the current definition of severe TR. Also, the improvement in the amount of TR following tricuspid intervention is not accounted for by the current definition of TR as different degrees of severity at the severe end was grouped under the same umbrella term of “severe.” There has been a recent call to expand the TR grading system, encompassing two more grades, namely “massive” and “torrential” TR, in the order of increasing severity. This seems appropriate as the patients enrolled in tricuspid intervention trials were found to have TR severity up to 2 grades above the current severe thresholds of effective regurgitant orifice area (EROA) 40 mm2, regurgitant volume (R Vol) 45 ml and vena contracta (VC) width 7 mm. The proposed grade of “massive” is defined by EROA 60–79 mm2, R Vol 60–74 ml and VC 14–20 mm, while “torrential” is defined by EROA ≥80 mm2, R Vol ≥75 ml, and VC ≥21 mm. The grading of TR requires a comprehensive, multi-parametric approach. In particular, quantitative assessment of TR should be performed in patients who require serial monitoring and quantification of treatment effect