An Adiabatic Bond Charge Model for the Phonon Properties of II-VI Materials and Superlattices.

I present an extension of the adiabatic Bond Charge model to study lattice dynamics of highly polar II-VI semi-conductors and semi-metals and CdTe-HgTe superlattices grown along (001) and (111) directions. This is the first attempt to study phonons in CdTe-HgTe superlattices. My results for phonon dispersion, specific heat and elastic constants for the six bulk materials are in good agreement with experimental observations. The best parameter sets for the six compounds show trends that are consistent with the parameters for group IV elemental semi-conductors and III-V compounds. For CdTe-HgTe superlattices, I find that the long range Coulomb interaction between particles situated on the opposite sides of the interface needs to be handled carefully to get positive eigenvalues and eigenvectors with proper symmetry and continuity. For CdTe-HgTe superlattices grown along (001) direction, many propagating modes are seen which travel with different wavevectors in CdTe and HgTe layers. The wavevectors in HgTe are different from the corresponding bulk values. This difference is significant for long wavelength modes. For (111) superlattices all the optical modes are either confined or interface modes. In both cases, the frequencies of the HgTe optical modes do not map well to the bulk LO branch. Also, in both cases the frequency of the highest HgTe LO mode does not reach the bulk limit even for 27 monolayer thick HgTe layers. These effects are interpreted in terms of the lowering of HgTe-frequencies from their bulk values due to the presence of higher charges in CdTe layers. My results for (001) superlattices indicate that all the un-identified peaks seen in the Raman spectra of these structures can be explained in terms of superlattice modes

All optical signal regeneration technique design and real time implementation for different modulation schemes using ultrascale FPGA

The all-optical signal regeneration is a demanding research area for long haul optical communication systems. Electronic signal regeneration is limited due to its real-time infeasibility in terms of data rate and accumulated losses; therefore, all-optical signal regeneration is utilized to overcome these issues. The existing all-optical signal regeneration techniques have not been able to facilitate low power consumption, demonstration of real-time low cost commercial based design systems and application for the optical systems. In this research, a new all-optical signal regeneration technique is developed using single- pump Phase Sensitive Amplification, designed Optical Frequency Locked Model and noise mitigation model. The designed technique consumes less power than existing signal regeneration techniques for 10Gb/s optical degraded signal for different amplitude and phase modulation formats transmitted at different transmission distances between 50 km to 250 km. The designed all-optical signal regeneration technique is realized using numerically and verified using Simulink model. A real-time demonstration and commercial design based application is developed using Xilinx KCU105 UltraScale FPGA. The new all-optical signal regeneration technique has achieved a very low Bit Error Rate (BER) of 10-13 at low received power of -16 dBm averagely for different transmission distances between 50 km to 250 km via simulation and experiment. The new all-optical signal regeneration technique consumes low power of -16dBm, compared to existing all-optical signal regeneration techniques that consumes -9dBm. The new all-optical signal regeneration technique consumes 45% less power; with low BER and low received power compared to existing technique. The new all-optical signal regeneration system offers, real time implementation, live monitoring and commercial based design for Differential Phase Shift keying (DPSK) Non-Return-to-Zero (NRZ), DPSK-Return-to-Zero (RZ), Binary PSK (BPSK), Differential BPSK, Quadrature PSK, Orthogonal Frequency Division Multiplexing (OFDM), Quadrature Amplitude Modulation (QAM), Binary Frequency Shift Keying (BFSK), 8-PSK, and On-Off Keying (OOK)

Pattern of lipid profile in type 2 diabetes mellitus-a study from north Bihar

Background: Diabetes mellitus refers to a group of common metabolic disorders that share the phenotype of hyperglycemia. Type 2 Diabetes Mellitus (DM) is a heterogeneous group of disorders characterized by variable degree of insulin resistance, impaired insulin secretion, and increased glucose production.Methods: To study of pattern of lipid profile in type 2 diabetes mellitus, 100 cases of type 2 Diabetes Mellitus attending the tertiary care centre were selected. The result was compared with 25 healthy, non-obese, non- diabetic and non-hypertensive subjects.Results: Triglyceride (TG) and very low-density lipoprotein (VLDL) were significantly higher whereas high density lipoprotein (HDL) levels lower in diabetics than healthy controls. Total cholesterol (TC) and low-density lipoprotein (LDL) were other fractions which were slightly above optimal levels in diabetics.Conclusions: From our study, it was concluded that diabetes mellitus has a real impact on lipid metabolism

Simulation Study of an Autonomous Ground Vehicle Model

The focus of the paper is to understand what an Autonomous Vehicle (AV) is, and realising a simulation model of intended vehicle for coarse testing of autonomous guidance navigation and control (AGNC) algorithm. MATLAB and SIMULINK are used as platform for development of this model. The model is developed to calculate the next position and direction of the vehicle based on the steering angle as commanded by the AGNC algorithm. This would lead towards the design of an scaled down model of AV using a modified radio control car chassis. The AV would then be equipped with a GPS and ultrasonic or infrared sensors to navigate it to a predetermined geographical location with obstacle avoidance. Keywords: Autonomous, Control, GPS, Model, Simulink, Vehicl

Design of cyclic prefix characteristic-based OFDM system for WiMAX technology

Worldwide interoperability for microwave access (WiMAX) offers the wireless connectivity using orthogonal frequency division multiplexing (OFDM) modulation is a proficient wireless technology that capacities high-speed data transmission facilities. The existing WiMAX techniques have the problem of increase in inter-symbol interference (ISI) and bit error rate (BER) at reduced power spectrum that degrades the performance of WiMAX system due to high data rate transmission. The utilization of different adaptive modulation techniques seen as a potential solution to reduce the ISI and BER for high data rate transmission. In this paper, OFDM is adapted using advanced modulation technique for WiMAX system. The technique proposes the cyclic prefix (CP) is utilized that include supplementary bits at the stage of the transmitter. The proposed technique offers minimization of ISI and improvement in BER. It is defined that performance of the existing CP system is equated with the designed single cyclic prefix (SCP) and double cyclic prefix (DCP) and non-cyclic prefix (NCP). BER, probability of error, and power spectral density are utilized to analyse the performance of the designed system. The OFDM based SCP and DCP and NCP for WiMAX are demonstrated for modulation techniques such as; QPSK, BPSK, and QAM. It is determined that BPSK has the smallest BER when compared to QPSK, 16-QAM, and 64-QAM modulations. It is also demonstrated that QPSK is also very competent, however, it has a higher BER as compared to BPSK modulation. It is also observed that 16-QAM and 64-QAM are less efficient in terms of BER compared to QPSK and BPKS modulations. 64-QAM offers the high data rates, and due to high SNR ratio. The designed system is tested for under AWGN and Rayleigh fading channel, and effect power spectral density of signal to noise ratio on OFDM for rayleigh fading channel are demonstrated for SCP and DCP and NCP. It is determined that the OFDM transmitter with proposed DCP for random signals is efficiently reducing the BER and ISI for WiMAX system

Study of the renal profile in relation to CD4 count in human immuno-deficiency virus patients from a tertiary centre of Bihar

Background: Human immuno-deficiency virus (HIV)-positive individuals are at increased risk for kidney disease, including HIV-associated nephropathy (HIVAN). HIV peptides rather than infection may be more important in pathogenesis of HIVAN. Much has been learnt about the pathogenesis and treatment of HIV-associated renal diseases because of the development of animal models and the molecular evaluation of clinical samples.Methods: We studied 90 consecutive patients with HIV and allocated them into 3 groups, each containing 30 patients on the basis of their CD4 counts. Then each group was divided into two subgroups, X and Y on the basis of whether they received anti-retroviral treatment (HAART) or not. Subgroup X received HAART and subgroup Y did not received HAART.Results: There was male preponderance (M: F=5.4: 1). Microalbuminuria, increased serum creatinine and decreased GFR was highest among HIV patients having CD4 count below 200 as compared to those having CD4 count of 200-350 and above 350.Conclusions: Our study demonstrates that both proteinuria and HIVAN are common in HIV infected patients. Proteinuria and glomerular filtration rate have a negative correlation with the CD4 count

Effect of general loss-cone distribution function on EIC waves in multi- component plasma-particle aspect approach

Electrostatic ion-cyclotron waves are investigated in multi-ion plasma (H+, He+ and O+) using particle aspect analysis. Variations with perpendicular wave number of wave frequency, resonant energy and growth rate with general loss-cone distribution function are studied. The whole plasma is considered to consist of resonant and non-resonant particles. The resonant particles participate in energy exchange while the non-resonant particles support the oscillatory motion of the wave. The wave is assumed to propagate obliquely to the static magnetic field. It is found that the frequency for the lighter ions increases then decreases by increasing the perpendicular wave number while the frequency for the heavier ions is constant. Perpendicular wave number decreases the growth rate of the wave and also decreases perpendicular resonant energy and increases parallel resonant energy. The effect of general loss-cone distribution is also discussed with multi-component plasma which increases the wave frequency, growth rate and parallel resonant energy while decreases the perpendicular resonant energy. The study may explain the EIC waves observed in auroral acceleration region. The results are interpreted for the space plasma parameters appropriate to the auroral acceleration region around the earth’s magnetosphere

Primary hyperparathyroidism: Experience from a tertiary care centre in Pakistan

Objective: To study the clinical, biochemical and radiological features and management outcomes of patients with primary hyperparathyroidism.Methods: This retrospective study was conducted at the Aga Khan University Hospital, Karachi, Pakistan and comprised data of patients with primary hyperparathyroidism from 2008 to 2017.Results: Out of 103 patients, 83(80.6%) were female. Overall mean age was 59.3±16.2 years. Musculoskeletal manifestations were seen in 60(58.3%) patients and renal manifestations in 28(27.2%). Ostieits fibrosa cystica was found in 04(3.88%) patients. Overall, Ultrasound neck and sestamibi scan localized the lesion in 66 (64.1%) and 77 (76.2%) patients respectively. Among 79 patients who underwent surgery, 67 (84.8%) patients had an adenoma, 05 (6.3%) had hyperplasia and 02(2.53%) patients had parathyroid carcinoma whereas histopathology was inconclusive in 5 (6.32%) out of the 79 surgically treated patients. Disease recurrence was seen in 13 out of 79(16.45%) patients who underwent surgery.Conclusion: Primary hyperparathyroidism is associated with significant morbidity in our population. Targeted measures like improving patient awareness, routine calcium screening, vitamin D supplementation and a high index of suspicion by the clinician may help in early diagnosis of the condition and thus reduce morbidity