Multi User Diversity Evaluation in MIMO HSDPA Downlink Channels

A multiple transmit antenna, single receive antenna (per receiver) downlink channel with limited channel feedback is considered. Given a constraint on the total system-wide channel feedback, the following question is considered: is it preferable to get low-rate feedback from a large number of receivers or to receive high-rate/high-quality feedback from a smaller number of (randomly selected) receivers. Acquiring feedback from many users allows multi-user diversity to be exploited, while highrate feedback allows for very precise selection of beamforming directions. It is shown that systems in which a limited number of users feedback high-rate channel information significantly outperform low-rate/many user systems. The marginal benefit of channel feedback is very significant up to the point where the CSI is essentially perfect

Fabrication of drug eluting medical device for treating stenosis by 3D printing and dip coating using aspirin as a model drug

3D printing is a new innovative manufacturing method for fabrication of customized medical devices. The customized medical devices & long-lasting implantable devices.has increasing demand for addressing some critical cases in surgeries. The main aim of this work was to explore the potential of 3D printing in Fabrication of medical devices and prosthetics. The characters of the polymers, the features of softwares were studied. The study showed that drug loading into filament through hot melt extrusion and followed by 3D printing has many defects such as denaturing of drugs at higher printing temperatures. The invention discloses the dip coating process  after fabrication of a 3D printed polymer structure. The drug release depends up on the surface area of the device, coated polymer, concentration of drug and thickness of the coat. The method for preparing the personalized drug eluting coronary stent / Bone wedges / Braces comprises the step that according to image data of coronary angiogram or volume rendered data from CT scans. The designing was done by adopting a QCA technique for measuring the diameter of a diseased coronary artery and reconstructing in a three-dimensional manner. According to indexes such as lesion vascular diameter, lesion length and lesion vascular pattern, a personalized coronary stent can be made for each patient in a customized manner and a stent most suitable for the lesion state of a patient can be prepared. Keywords: 3D printing, manufacturing method, Fabrication of medical device

Cd4 count at the time of presentation in newly diagnosed HIV patients in a tertiary care hospital in south India: implications for the programme

Background: Lower CD4 count at initiation of antiretroviral therapy (ART) can have a significant negative impact on subsequent disease progression and mortality among HIV patients. Hence, author assessed the status of the CD4 count at the time of diagnosis and factors associated with lower CD4 count among newly diagnosed HIV cases.Methods: A prospective observational study was conducted in a single integrated counseling and testing center, affiliated with a Medical College and Hospital, Andhra Pradesh. All newly diagnosed HIV cases in the setting between January to December 2017 were included. The CD4 count was assessed as per national guidelines for enumeration of CD4 2015.Results: The final analysis included 125 participants. The mean CD4 count at diagnosis was 276.51±228.37. Only 19 (15.20%) people had CD4 count >500, 47 (37.60%) had between 200-500 and 59 (47.20%) had CD4 count <200. Only 20% had appropriate knowledge of treatment. Among the study population, 43 (34.70%) had symptomatic conditions attributed to HIV infection, 44 (35.50%) participants had an AIDS-defining illness at the time of diagnosis. Only 3 (2.40%) had voluntary counseling and testing. Even though male gender, poor educational status, having more sexual partners, poor knowledge related to HIV diagnosis and treatment was associated with higher odds of low CD4 count (<200), none of the associations were statistically significant.Conclusions: The mean CD4 count was low and almost half of newly diagnosed cases had low CD4 count (<200) at the time of diagnosis. There is a strong need to intensify the efforts to fill the gaps in the screening for the early diagnosis to maximize the benefits of HAART and to stop the spread of the infection

The Challenge of Continuous Mobile Context Sensing

National Research Foundation (NRF) Singapore under IDM Futures Funding Initiativ