1H‐decoupling and Isotopic Labeling for the Measurement of the Longitudinal Relaxation Time of Hyperpolarized 13C‐Methylenes in Choline Analogs

The T₁ of a hyperpolarized site in solution is a key parameter that determines the time‐window in which its NMR signals are observable. For ¹³C sites adjacent to protons, ¹H‐decoupling has been shown to increase the hyperpolarized signal resolution and SNR. Additionally, polarization transfer to protons has shown utility in increasing the sensitivity of detection. However, ¹H‐decoupling could lead to a change in the decay rate of a hyperpolarized ¹³C site. Here we tested this possible effect in a case where the protons are directly bound to an sp³ hyperpolarized ¹³C site (using [1,2‐¹³C₂]choline) and ¹H‐decoupling was applied continuously throughout the hyperpolarized decay measurement. We found that ¹H‐decoupling did not lead to any significant changes in the ¹³C polarization decay time but did result in the expected collapse of J‐coupling and produced sharper signals. This result suggested that ¹H‐decoupling did not affect the decay rate of hyperpolarized sp^{3 13}C sites. The deuterium‐substitution approach (using [1,1,2,2‐D₄,1‐¹³C]choline) showed a dramatic prolongation of T₁. Upper bounds on the T₁ of all investigated sites were calculated.     

Recursive structures and finite impulse response implementations oflinear multiuser detectors for an asynchronous CDMA system

We present order-recursive structures for implementing the linear decorrelating and linear minimum mean square error (MMSE) detectors in a computationally efficient manner. These infinite memory length, linear time invariant, noncausal systems can be approximated by implementing them as K-input K-output finite impulse response (FIR) filters. We developed a linear multiuser receiver architecture called a recursive linear multiuser detector which has lower computational and memory requirements then an equivalent tap delay line FIR filter implementation. We establish the tradeoff between window length and bit error rate and find that relatively small window size yields performance indistinguishable from the ideal decorrelating detector and the ideal MMSE detector     

Antihyperglycaemic efficacy of kombucha in streptozotocin-induced rats

Kombucha is a fermented tea beverage produced by fermenting sugared black tea with kombucha mat (consists of bacteria and yeast strains). Diabetes mellitus is group of metabolic disorders characterized by hyperglycaemia resulting from defects in insulin secretion, action or both. The present study was aimed to delineate the antihyperglycaemic effect of lyophilized extract of kombucha in streptozotocin-induced experimental rats. After the experimental period of 45 days we observed that kombucha supplementation with 6 mg/kg bw significantly decreased glycosylated haemoglobin (HbA_1c) and increased the levels of plasma insulin, haemoglobin and tissue glycogen which was decreased up on streptozotocin (STZ) treatment and also significantly reversed the altered activities of gluconeogenic enzymes such as glucose-6-phosphatase, fructose-1,6-bisphosphatase and glycolytic enzymes such as hexokinase in the tissues of experimental rats. Thus, our results substantiate that kombucha found to exert hypoglycaemic effect in STZ-induced diabetic rats. These findings suggest that kombucha may be considered as a potential functional food candidate for future applications as functional food supplement for the treatment and prevention of diabetes.     

Discrimination of maize crop with hybrid polarimetric RISAT1 data

Microwave remote sensing provides an attractive approach to determine the spatial variability of crop characteristics. Synthetic aperture radar (SAR) image data provide unique possibility of acquiring data in all weather conditions. Several studies have used fully polarimetric data for extracting crop information, but it is limited by swath width. This study aimed to delineate maize crop using single date hybrid dual polarimetric Radar Imaging Satellite (RISAT)-1, Fine Resolution Stripmap mode (FRS)-1 data. Raney decomposition technique was used for explaining different scattering mechanisms of maize crop. Supervised classification on the decomposition image discriminated maize crop from other land-cover features. Results were compared with Resourcesat-2, Linear Imaging Self Scanner (LISS)-III optical sensor derived information. Spatial agreement of 91% was achieved between outputs generated from Resourcesat-2, LISS-III sensor and RISAT-1 data.     

Designing a mobile broadband wireless access network

In this paper, a new OFDM-based air interface technology for a mobile broadband wireless system is described. The technology leverages the standard Internet protocol (IP) network elements to build the system and deploys a new air interface technology based on OFDMA. Cross-layer optimization played a major role in the design where the choices made in the physical, MAC, and link layers are also driven by the goal of extending the Internet to the wireless space. A major physical layer benefit of this air interface comes from the orthogonality property that the results in the elimination of in-cell interference are averaged and a worst-case interferer does not limit the system performance. The physical layer features not only result in high capacity but also provide very fine granularity of allocating air link resources, which improves the MAC and link-layer efficiency. The MAC and link layer provide contention-free, fast control channels between the RAR and the WTs. These channels are used to ferry a variety of signaling such as assignments of traffic channel, acknowledgements, channel quality, and traffic request reports. This holistic approach allows for a scheduler that could not only achieve high spectral efficiency but also allow for a fine control over QoS attributes such as latency, reliability, and service differentiation.     

On the design of quadratic filters with application to imageprocessing

We present a systematic design method for quadratic filters, and show an example for an edge detector. Our design maximizes the output signal-to-noise ratio (SNR) constrained to detect desired signals while ignoring specified error signals such as shot noise. This filter compares favorably with Sobel and morphological detectors of similar complexity.     

Time and frequency domain identification and analysis of a permanent magnet synchronous servo motor

Abstract

This study employed the approach of non‐linear autoregressive moving average model with exogenous inputs (NARMAX) to analyze the dynamics of a Permanent Magnet Synchronous Motor (PMSM). The non‐linearity in PMSM including cogging force, reluctance force and force ripple is difficult to estimate. By using the NARMAX approach, thrust‐speed relationship and thrust‐position relationship could be analyzed by identifying both time and frequency domain models of the system. The frequency domain analysis is studied by mapping the discrete‐time NARMAX models into generalized frequency response functions (GFRFs) to reveal the non‐linear coupling between the various input spectral components and the energy transfer mechanisms in the system. From the results, the interpretation of the higher‐order GFRFs has been comprehensively studied and non‐linear effects have been related to the physical models of the systems.