Alias-free, real coefficient m-band QMF banks for arbitrary m

Based on a generalized framework for alias free QMF banks, a theory is developed for the design of uniform QMF banks with real-coefficient analysis filters, such that aliasing can be completely canceled by appropriate choice of real-coefficient synthesis filters. These results are then applied for the derivation of closed-form expressions for the synthesis filters (both FIR and IIR), that ensure cancelation of aliasing for a given set of analysis filters. The results do not involve the inversion of the alias-component (AC) matrix

Theory and design of uniform DFT, parallel, quadrature mirror filter banks

In this paper, the theory of uniform DFT, parallel, quadrature mirror filter (QMF) banks is developed. The QMF equations, i.e., equations that need to be satisfied for exact reconstruction of the input signal, are derived. The concept of decimated filters is introduced, and structures for both analysis and synthesis banks are derived using this concept. The QMF equations, as well as closed-form expressions for the synthesis filters needed for exact reconstruction of the input signalx(n), are also derived using this concept. In general, the reconstructed. signalhat{x}(n)suffers from three errors: aliasing, amplitude distortion, and phase distortion. Conditions for exact reconstruction (i.e., all three distortions are zero, andhat{x}(n)is equal to a delayed version ofx(n))of the input signal are derived in terms of the decimated filters. Aliasing distortion can always be completely canceled. Once aliasing is canceled, it is possible to completely eliminate amplitude distortion (if suitable IIR filters are employed) and completely eliminate phase distortion (if suitable FIR filters are employed). However, complete elimination of all three errors is possible only with some simple, pathalogical stable filter transfer functions. In general, once aliasing is canceled, the other distortions can be minimized rather than completely eliminated. Algorithms for this are presented. The properties of FIR filter banks are then investigated. Several aspects of IIR filter banks are also studied using the same framework

SIMVASTATIN DOES NOT SENSITIZE IBC3 HER2+ INFLAMMATORY BREAST CANCER BRAIN METASTASES TO WHOLE BRAIN IRRADIATION IN AN IMMUNOCOMPROMISED MOUSE MODEL

Retrospective data analysis suggests that inflammatory breast cancer (IBC) patients who take statins have better locoregional control after radiotherapy than those who do not [23]. Our lab has previously demonstrated that simvastatin radiosensitizes IBC cells in vitro [23], and brain metastases have strong expression of cholesterol-regulation genes compared to lung metastases in vivo [unpublished]. Delaying whole-brain irradiation (WBI) beyond 21 days is insufficient to reduce the incidence of brain metastases (developed by injecting IBC3 cells through the tail vein) in our mouse model because even high rates of cell killing leave substantial cell volume in established metastases [unpublished]. With the above data, I hypothesized that the combination of simvastatin and whole-brain radiation will reduce the incidence of established brain metastases in vivo. I performed two in vivo experiments—in the first, a single-fraction, 10-Gy WBI dose was used, and in the second experiment, a 9-Gy WBI dose was given in 3 fractions of 3 Gy each. The simvastatin dose was kept constant and was mixed with drinking water in both experiments. Brain metastatic lesions were quantified by stereo-microscopy. Brains were cryo-sectioned into mirror sections for mass spectrometry-based tissue imaging and H&E staining. There was a significant reduction (P \u3c 0.05) in brain metastatic burden in the group treated with 10 Gy WBI alone compared to no treatment. Simvastatin by itself did not significantly reduce the brain metastatic burden compared to no treatment. There was no significant reduction in brain metastatic burden in the combination group compared to the no-treatment or radiation-alone group. There was no significant difference in the incidence of brain metastasis between any of the four treatment groups. Repeating the experiment with a 9 Gy–dose of WBI given in 3 fractions of 3 Gy each also demonstrated no synergy between simvastatin and radiation in this model. Mass spectrometry-based tissue imaging revealed that treatment with 10 Gy radiation (both as a single-agent and in combination with statins) increased cholesterol (based on its m/z value of 369.35) levels compared to the no-treatment or simvastatin-alone group. Mice brain treated with simvastatin alone had low cholesterol levels compared to the no-treatment group, confirming the role of statins in inhibiting cholesterol biosynthesis. Contrary to my hypothesis, the metastatic burden did not correlate with cholesterol levels in the brain parenchyma for any of the treatment groups. Thus, simvastatin failed to radiosensitize brain metastases in our model, consistent with our published mathematical model [35] and a recently published clinical trial [28]

Application of signal processing techniques for measurement of muscle fiber conduction velocity

The objectives of this study were to evaluate if muscle fiber conduction velocity (MFCV) could be used as a reliable indicator of fatigue and to characterize the recovery of MFCV after a fatiguing contraction. The decline of MFCV with fatigue was modelled using linear regression and compared with the decline in median frequency (MF). It was found that the percent decline in MF with fatigue was greater than that of MFCV with fatigue and that the decline of MFCV was consistent in all subjects tested. It was thus determined that MFCV could be used as a reliable indicator of fatigue. Possible explanations for the recovery of MFCV after fatigue were given. The recovery curves for all subjects were curve fit using the exponential peeling technique. A comparison of the time constants showed that 8 out of 9 subjects had values between 2-4 minutes, indicating that the recovery process had a similar response in these 8 subjects. Decomposition of the EMG is a useful tool which helps us better understand the functioning of the neuromuscular system. An algorithm was developed to decompose the EMG into its constituent motor units based on the work done by Deluca et al. Preliminary results were obtained. However, further research is needed in this area

Recovering the orthogonal polynomials from its specific spectral transformations

In this work, the concept of quasi-type Kernel polynomials with respect to a moment functional is introduced. Difference equation satisfied by these polynomials along with the criterion for orthogonality conditions are discussed. Recovering the source orthogonal polynomial involving the linear spectral transformation is provided. This process involves an expression of ratio of kernel polynomials. Special cases of such ratios in terms of certain continued fractions are exhibited.Comment: 21 PAGE

Vasoplegic syndrome after off pump coronary artery bypass grafting surgery

We report a case of 48-years-old man who developed nor-epinephrine resistant vasoplegic syndrome after elective off pump coronary artery bypass grafting surgery. The failure of norepinephrine to improve the patients’ hemodynamics promted us to start treatment with vasopressin. Within an hour, the hemodynamics begin to improve. After 4 hours, patient was stable enough to be weaned from vasopressin, extubated at the end of 24 hrs and shifted to ward at the end of 48 hours. Vasoplegic syndrome can occur commonly after cardiopulmonary bypass and incidence can go up to 10%. This case was reported to insist upon the fact that vasoplegic syndrome can occur even after off pump surgeries. Herein we discuss the aetiology, risk factors, pathophysiology and prophylactic measures to be taken, for the prevention of vasoplegic syndrome