Improved Random Demodulator for Compressed Sensing Applications

The advances in the field of signal processing have led to the continuous increase in the bandwidth of signals. Sampling these signals becomes harder and harder due to the increased bandwidth. This brings in need for a complex high rate ADCs to meet the Nyquist rate which is the minimum rate to avoid aliasing. For a given increase in bandwidth, there has to be a corresponding increase in the sampling rate of ADC. This might not be possible in the near future at the current rate of increase in bandwidth. Hence, there is a need to replace the current Nyquist rate sampling method by a process that relaxes the requirements but still keeps the quality of signal reconstruction good . Compressed sensing is a new technique in the field of signal acquisition. Compressed sensing allows a signal to be acquired below Nyquist rate if the signal is sparse in a given domain. Compressed sensing makes possible to acquire sparse signals at rates below Nyquist rate. Signals like audio and images are sparse and can be sampled at a rate below the Nyquist rate. The random demodulator (RD) is a hardware architecture that is used to implement compressed sensing. A direct implementation of compressed sensing in hardware requires several copies of the RD. To reduce the complexity fewer RDs can be used. Usage of fewer RDs comes at the cost of decreased signal reconstruction performance. The contribution of this thesis is about improving the efficiency of RD. First contribution of this thesis involves proposing a new RD architecture that improves signal reconstruction quality using a post-acquisition randomization step. The second contribution of this thesis is to develop a hardware platform for compressed sensing using field programmable analog arrays (FPAAs) and field programmable gate arrays (FPGAs). This platform can be used to test new architectures of RD in hardware

Identification of host factors in swine respiratory epithelial cells that contribute to host anti-viral defense and influenza virus replication

Swine influenza viruses (SIV) are a common and an important cause of respiratory disease in pigs. Pigs can serve as mixing vessels for the evolution of reassortment viruses containing both avian and human signatures, which have the potential to cause pandemics. NS1 protein of influenza A viruses is a major antagonist of host defence and it regulates multiple functions during infection by interacting with a variety of host proteins. Therefore, it is important to study swine viruses and NS1-interacting host factors in order to understand the mechanisms by which NS1 regulates virus replication and exerts its host defense functions. Influenza A viruses enter the host through the respiratory tract and infect epithelial cells in the respiratory tract, which form the primary sites of virus replication in the host. Thus, studying SIV infection in primary swine respiratory epithelial cells (SRECs) would resemble conditions similar to natural infection. The objectives of this study were to identify NS1-interacting host factors in the virus-infected SRECs and to understand the physiological role of at least one of the factors in influenza virus infection. The approaches to meet this objective were to generate a recombinant SIV carrying a Strep-tag in the NS1 protein, infect SRECs with the Strep-tag virus, purify NS1-interacting host protein complex from the infected cells by pull-down using strep-tactin resin and then study the physiological role of one of the NS1-interacting partners during influenza infection. Using a reverse-genetics strategy, a recombinant virus carrying the Strep-tag NS1 was successfully rescued and the SRECs were infected with this recombinant virus. The Strep-tag in the NS1 protein facilitated the isolation of an intact NS1-interacting protein complex and the proteins present in the complex were identified by liquid chromatography-tandem mass spectrometry. The identified proteins were grouped to enrich for different functions using bioinformatics. This gave an insight into the different functions that NS1 may regulate during infection and the potential host partners involved in these functions. Among the host proteins identified as potential interaction partners, RNA helicases were particularly of interest to study. Influenza being an RNA virus, RNA helicases could have important functions in the virus life cycle. Among the identified RNA helicases, DDX3 has been shown to regulate IFNβ induction and affect the life cycle of a number of viruses. However, its function in influenza A virus life cycle has not been studied. Hence, this study explored whether DDX3 has any role in the influenza A virus life cycle. Immunoprecipitation studies revealed viral proteins NP and NS1 as direct interaction partners with DDX3. DDX3 is a known component of stress granules (SGs) and influenza A virus lacking the NS1 gene is reported to induce SG formation. Therefore, the role of DDX3 in SG formation, induced by PR8 influenza A virus lacking NS1 (PR8 del NS1) was explored. The results from this study showed that DDX3 co-localized with NP in SGs indicating that DDX3 may interact with NP in the SGs. NS1 protein was found to inhibit virus-induced SGs and DDX3 downregulation impaired virus-induced SG formation. The contribution of the different domains of DDX3 to viral protein interaction and virus-induced SG formation was also studied. While DDX3 helicase domain did not interact with NS1 and NP, it was essential for DDX3 localization in virus induced SGs. Moreover, DDX3 downregulation resulted in the increased replication of PR8 del NS1virus, accompanied by an impairment of SG induction in infected cells. Since DDX3 is reported to regulate IFNβ induction, the role of DDX3 in influenza A virus induced IFNβ induction was also examined. Using small molecule inhibitors and siRNA-mediated gene knockdown, the RIG-I pathway was identified as the major contributor of influenza induced IFNβ induction in newborn porcine tracheal epithelial (NPTr) cells. DDX3 downregulation and overexpression also showed that DDX3 has an inhibitory effect on IFNβ expression induced by both influenza infection and low molecular weight (LMW) poly I:C treatment, which is also a RIG-I ligand. RNA competition assay to identify the mechanism of DDX3-mediated inhibition, showed that RIG-I binding affinity to its ligands LMW poly I:C and influenza viral RNA (vRNA) is much higher than that of DDX3. Furthermore, DDX3 downregulation enhanced titers of the PR8 del NS1 virus, while it did not affect the titers of the wild-type strains of PR8 and SIV/SK viruses. Overall, the results show that DDX3 has an antiviral role and the SG regulatory function of DDX3 has a profound effect on virus replication than the IFNβ regulatory function

IMPACT OF RAPID EYE MOVEMENT SLEEP DEPRIVATION ON HYPOTHALAMIC-PITUITARYTESTICULAR AXIS IN WISTAR ALBINO RATS

Objectives: The objectives of the study were to study the impact of rapid eye movement (REM) sleep deprivation (SD) on the hypothalamic-pituitary-testicular (HPT) axis in the Wistar albino rats.Methods: Adult male Wistar albino rats weighing about 200 g were segregated into Group I–IV of control, 48 h SD, 72 h SD, and 96 h SD, respectively, in a custom-made SD tank. After SD procedure, the sexual behavior of rats was assessed, after which blood was collected from the animals for the estimation of HPT and stress hormones and then the testicles were used for histological studies.Results: SD has increased (p<0.05) the mounting latency and intromission latency and decreased (p<0.05) the mounting frequency and intromission frequency compared with control group. A significant increase (p<0.05) in corticosterone, follicle stimulating hormone levels and a significant decrease (p<0.05) in gonadotropin-releasing hormone, luteinizing hormone and testosterone levels were observed in all the SD groups when compared with control group. SD-induced testis architecture displayed sperm retention, sperm reduction, and shape alteration when compared to the control group. Furthermore, apoptotic bodies were observed in the testis of 72 h and 96 h of sleep-deprived animals.Conclusion: Outcome of the project reveals that out of 48 h, 72 h, and 96 h of SD, 96 h of SD has a great impact on sexual behavior, HPT hormones, and testicular morphology

Multi-Objective Optimization of Construction Project Time-Cost-Quality Trade - off Using Differential Evolution Algorithm

Time and cost are among the important aspects considered for every construction project. Many research approaches have been followed to model time-cost relationship. There is a constant rise in the use of innovative contract methods which provide incentives for maximizing quality. There is an increasing pressure to improve the project performance due to the innovative contracting methods which necessitate developing models incorporating quality along with time and cost. A main contractor normally subcontracts most of the tasks of a project for improving project performance. It is always a complex and challenging task for a main contractor, to choose a correct bid which satisfies the time, cost and quality requirements of a project. In the present study, a differential evolution algorithm is used to solve this multi-objective time-cost-quality optimization problem. Two case studies are analyzed and the results obtained compared with the existing approaches to test the applicability and efficiency of the algorithm. It is evident from the results that the differential evolution algorithm performs efficiently in locating the optimal solution with minimum function evaluation

Palmoplantar Psoriasis: A Comparative Therapeutic study

INTRODUCTION: Psoriasis is an immunologically mediated inflammatory dermatosis characterized by erythematous scaly plaques, extremely variable in clinical manifestations ranging from innocuous lesions to life threatening pustular & erythrodermic psoriasis. Palmoplantar psoriasis present as hyperkeratotic plaques with fissures leading to significant disability. Palmoplantar psoriasis can managed with either topical agents, phototherapy or systemic agents AIMS AND OBJECTIVES: 1. To study the therapeutic efficacy of a) oral methotrexate, b) hand & foot phototherapy using NBUVB, c) topical calcitriol with clobetasol propionate ointment. 2. To do clinical evaluation using PASI scoring and assess quality of improvement using DLQI. MATERIALS AND METHODS: Sixty patients with palmoplantar psoriasis were randomly selected. Clinical examination and necessary investigations were done and PASI scoring calculated to assess the area involved. Patients were grouped under three groups. Group A patients were put on calcipotriol with clobetasol propionate ointment. Group B patients had hand and foot NB-UVB. Group C patients were put on tablet methotrexate. OBSERVATION AND RESULTS: Thirty three patients were males with male to female ratio of 1.22:1. Mean age of patients was 36. Mean duration of illness was 11months. Most of the patients were manual labourers. 36 patients had lesions over palms and soles, 9 palms alone and 15 involving soles. Mean PASI reduction at 16weeks was maximum with methotrexate. Compliance was good with methotrexate and topical group. Relapse cases were seen with methotrexate. CONCLUSION: There is no significant change in clinico-epidemiology and presentation of palmoplantar psoriasis. Methotrexate is the most efficacious modality in treatment of palmoplantar psoriasis

Finite element characterisation of graphene-silicon hybrid waveguides

Recent years have witnessed remarkable progress in nanoscience and nonlinear optics research, paving entry of 2D materials such as graphene, phosphorene, silicene, and so on. Graphene has extraordinary optical, electrical, mechanical and thermal properties. The uniqueness of graphene lies in its modulation depth (> 90%) and signal attenuation (< 5%), achieved by controlling its Fermi level through gate voltage. It is envisioned that graphene-based modulators would be the ultimate high-speed modulator of the future, performing at speeds up to 10 times faster than existing ones. The accuracy of such solutions lies in determining the permittivity (εr) of materials used. Graphene possesses complex conductivity (Ϭ(ω) = Ϭ1 + jϬ2) and permittivity (ε(ω) = ε1 + jε2). Using Kubo formalism, we derived an analytical method for finding the conductivity of graphene (Ϭg,interband +Ϭg,intraband) and then the complex permittivity (εg). The values of ε(ω) are plotted as a function of chemical potential (μ, eV), wavelength (λ, nm) and thickness of graphene layers (t(g)). Benchmarking was carried out using two solvers viz., complex and perturbation to ascertain the suitability of the method. Effective mode index (n(eff)) and absorption (α) are calculated for quasi-TE and quasi-TM guided modes of the waveguide. We found that the waveguide performance parameters are highly influenced by the position of graphene layers in the waveguide and the thickness and type of dielectric material that encapsulate the graphene layers. Two positions viz., graphene-as-top layer and graphene-as-slot layer were analysed. Three dielectric materials, hBN, Al2O3 and HfO2, classified as low-, high-and very-high index, respectively, are chosen. For operation wavelength range (1.3{1.7μm) and for varying dielectric layer thickness from 5 to 70 nm, the plots for neff and α (dB/μm) are obtained. Performance parameters such as extinction ratio (ER) and insertion loss (IL) were calculated for varying dielectric thickness (5-70 nm). ER and IL are achieved within the ranges 20-70 and 3-4 dB/μm, respectively. We inferred that to enhance the modal properties (n(eff) and α), graphene-as top layer waveguide can have a combination of very high-index (εr = 25) dielectric material (thickness > 15 - 20 nm) encapsulating graphene whereas a very high-index dielectric with reduced thickness (< 5 - 10 nm) encapsulating graphene is suitable for graphene-as-slot layer waveguide