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Orthogonal Frequency Division Multiplexing (OFDM) is a multi-carrier system where data bits are encoded to multiple sub-carriers, while being sent simultaneously. The basic idea of OFDM is to divide the available spectrum in a number of narrowband and low-rate orthogonal subcarriers, to prevent interference between the closely carriers. This makes the OFDM system resistant to multipath effect. Due to wide use of OFDM, it is essential to develop a Digital Signal Processor (DSP) to generate OFDM signals present in the various standards, using a reconfigurable platform like Field Programmable Gate Array (FPGA). The objective of the project is to design and implement OFDM transmitter and receiver on FPGA hardware. This project concentrates on developing custom single purpose processor for OFDM with Fast Fourier Transform i.e., FFT and Inverse Fast Fourier Transform i.e., IFFT in an efficient way. The work also includes design of a mapping module (Modulator)(64-QAM), serial to parallel, parallel to serial converter and Vedic multiplier modules and interconnections between them.Basically we are integrating different proposed ideas into a single paper. The design uses 64-point FFT and IFFT for the processing module, which indicate that the processing block contain 64 inputs data. This design is simulated on Zynq UltraScale+ FPGA Board(Part:xczu7ev-ffvf1517-1LV-i) and tested and verified using Xilinx Vivado 2020 software. Simulations on Python is also done to compare our result with the results obtained from that of use of FPGA.

The COVID-19 pandemic has affected every sector of healthcare. Interventional Radiology in many instances continues to provide frontline care during this pandemic. The purpose of this article is to assist Interventional Radiologists in their preparation to face the challenges, by summarizing global experiences and guidelines. We provide a basic framework that can be used to prepare institue specific guidelines in coordination with multidisciplinary teams and hospital administration.

Author(s): Heba, Elhamy R; Desai, Ajinkya; Zand, Kevin A; Hamilton, Gavin; Wolfson, Tanya; Schlein, Alexandra N; Gamst, Anthony; Loomba, Rohit; Sirlin, Claude B; Middleton, Michael S | Abstract: PurposeTo determine the accuracy and the effect of possible subject-based confounders of magnitude-based magnetic resonance imaging (MRI) for estimating hepatic proton density fat fraction (PDFF) for different numbers of echoes in adults with known or suspected nonalcoholic fatty liver disease, using MR spectroscopy (MRS) as a reference.Materials and methodsIn this retrospective analysis of 506 adults, hepatic PDFF was estimated by unenhanced 3.0T MRI, using right-lobe MRS as reference. Regions of interest placed on source images and on six-echo parametric PDFF maps were colocalized to MRS voxel location. Accuracy using different numbers of echoes was assessed by regression and Bland-Altman analysis; slope, intercept, average bias, and R2 were calculated. The effect of age, sex, and body mass index (BMI) on hepatic PDFF accuracy was investigated using multivariate linear regression analyses.ResultsMRI closely agreed with MRS for all tested methods. For three- to six-echo methods, slope, regression intercept, average bias, and R2 were 1.01-0.99, 0.11-0.62%, 0.24-0.56%, and 0.981-0.982, respectively. Slope was closest to unity for the five-echo method. The two-echo method was least accurate, underestimating PDFF by an average of 2.93%, compared to an average of 0.23-0.69% for the other methods. Statistically significant but clinically nonmeaningful effects on PDFF error were found for subject BMI (P range: 0.0016 to 0.0783), male sex (P range: 0.015 to 0.037), and no statistically significant effect was found for subject age (P range: 0.18-0.24).ConclusionHepatic magnitude-based MRI PDFF estimates using three, four, five, and six echoes, and six-echo parametric maps are accurate compared to reference MRS values, and that accuracy is not meaningfully confounded by age, sex, or BMI.

PurposeThe aim of the study was to determine in patients undergoing gadoxetate disodium (Gx)-enhanced MR exams whether proton density fat fraction (PDFF) estimation accuracy of magnitude-based multi-gradient-echo MRI (MRI-M) could be improved by using high flip angle (FA) on post-contrast images.Materials and methodsThirty-one adults with known or suspected hepatic steatosis undergoing 3T clinical Gx-enhanced liver MRI were enrolled prospectively. MR spectroscopy (MRS), the reference standard, was performed before Gx to measure MRS-PDFF. Low (10°)- and high (50°)-flip angle (FA) MRI-M sequences were acquired before and during the hepatobiliary phase after Gx administration; MRI-PDFF was estimated in the MRS-PDFF voxel location. Linear regression parameters (slope, intercept, average bias, R 2) were calculated for MRS-PDFF as a function of MRI-PDFF for each MRI-M sequence (pre-Gx low-FA, pre-Gx high-FA, post-Gx low-FA, post-Gx high-FA) for all patients and for patients with MRS-PDFF&nbsp

A computational study is carried out to understand the aerodynamics of shuttlecocks used in the sport of badminton. The speed of the shuttlecock considered is in the range of 25–50 m/s. The relative contribution of various parts of the shuttlecock to the overall drag is studied. It is found that the feathers, and the net in the case of a synthetic shuttlecock, contribute the maximum. The gaps, in the lower section of the skirt, play a major role in entraining the surrounding fluid and causing a difference between the pressure inside and outside the skirt. This pressure difference leads to drag. This is confirmed via computations for a shuttlecock with no gaps. The synthetic shuttle experiences more drag than the feather model. Unlike the synthetic model, the feather shuttlecock is associated with a swirling flow towards the end of the skirt. The effect of the twist angle of the feathers on the drag as well as the flow has also been studied.

Objectives: To study the results of magnetic resonance-guided focused ultrasound surgery (MRgFUS) treatment carried out on Indian patients in our Hospital. Materials and Methods: Fifty Indian women (mean age = 36.2 ± 8.3 years) were treated for fibroids as outpatients using the ExAblate MRgFUS system (InSightec). Non-perfused volumes (NPVs) were measured immediately after treatment to calculate the treatment outcomes. A validated symptom-specific questionnaire to record their symptoms prior to treatment and six months following treatment was completed by patients. The size of the fibroids was measured on the day of the treatment and during the 6-month checkup to calculate shrinkage. Adverse events during and following treatment were recorded and monitored. Results: The average NPV ratio measured after the treatment was 88% ± 6%, indicative of high ablated fibroid tissue. Prior to treatment, the mean Symptoms Severity Score was 56.9 ± 4.8 (n = 50), which is indicative of highly symptomatic patients. Six months following treatment, there was an average fibroid shrinkage of 30% ± 11%, and a significant decrease in the mean score to 28.6 ± 6.0 (n = 50) (P < 0.001). There were no reports of serious or unexpected adverse events at any point during treatment or during the follow-up period from any of the 50 women treated in the current study. Conclusions: The current results obtained after 6 months of treatment corroborated previous data on the safety and efficacy of MRgFUS for treating uterine fibroids. This is the first publication that provides such data for a large cohort of Indian women.

© 2014 RSNA. Purpose: To evaluate the diagnostic performance of previously proposed high-specificity magnetic resonance (MR) imaging'estimated proton density fat fraction (PDFF) thresholds for diagnosis of steatosis grade 1 or higher (PDFF threshold of 6.4%), grade 2 or higher (PDFF threshold of 17.4%), and grade 3 (PDFF threshold of 22.1%) by using histologic findings as a reference in an independent cohort of adults known to have or suspected of having nonalcoholic fatty liver disease (NAFLD). Materials and Methods: This prospective, cross-sectional, institutional review board' approved, HIPAA-compliant single-center study was conducted in an independent cohort of 89 adults known to have or suspected of having NAFLD who underwent contemporaneous liver biopsy. MR imaging PDFF was estimated at 3 T by using magnitude-based low'flip-angle multiecho gradientrecalled-echo imaging with T2∗ correction and multipeak modeling. Steatosis was graded histologically (grades 0, 1, 2, and 3, according to the Nonalcoholic Steatohepatitis Clinical Research Network scoring system). Sensitivity, specificity, and binomial confidence intervals were calculated for the proposed MR imaging PDFF thresholds. Results: The proposed MR imaging PDFF threshold of 6.4% to diagnose grade 1 or higher steatosis had 86% sensitivity (71 of 83 patients; 95% confidence interval [CI]: 76, 92) and 83% specificity (five of six patients; 95% CI: 36, 100). The threshold of 17.4% to diagnose grade 2 or higher steatosis had 64% sensitivity (28 of 44 patients; 95% CI: 48, 78) and 96% specificity (43 of 45 patients; 95% CI: 85, 100). The threshold of 22.1% to diagnose grade 3 steatosis had 71% sensitivity (10 of 14 patients; 95% CI: 42, 92) and 92% specificity (69 of 75 patients; 95% CI: 83, 97). Conclusion: In an independent cohort of adults known to have or suspected of having NAFLD, the previously proposed MR imaging PDFF thresholds provided moderate to high sensitivity and high specificity for diagnosis of grade 1 or higher, grade 2 or higher, and grade 3 steatosis. Prospective multicenter studies are now needed to further validate these high-specificity thresholds.