134 research outputs found

    Transceiver Design for MIMO Systems with Individual Transmit Power Constraints

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    This paper investigate the transceiver design for single-user multiple-input multipleoutput system (SU-MIMO). Joint transceiver design with an improper modulation is developed based on the minimum total mean-squared error (TMSE) criterion under two different cases. One is equal power allocation (EPA) and other is the power constraint that jointly meets both EPA and total transmit power constraint (TTPC) (i.e ITPC). Transceiver is designed based on the assumption that both the perfect and imperfect channel state information (CSI) is available at both the transmitter and receiver. The simulation results show the performance improvement of the proposed work over conventional work in terms of bit error rate (BER)

    Molecular Engineering of Conjugated Polymers for Sensor Applications

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    In recent years, the application of fluorescent conjugated polymers for sensing chemical and biological analytes has received much attention from many researchers. A promising development in this direction was the fabrication of conducting polymer-based sensors for the detection of metal ions, small organic molecules and biomolecules. Herein, we have designed, synthesized and studied a series of copolymers containing alternate phenylene and 2,5- or 2,6-substituted pyridine rings. The basic N-atom of the pyridine ring and the adjacent –OH group from the phenyl ring provide binding sites for metal ions. Another series of water-soluble conjugated polymers with propoxy sulfonate side chains are investigated for biosensor applications. Significant quenching of the polymer fluorescence upon addition of viologen derivatives was also observed. The quenching effect on the polymer fluorescence confirmed that the newly synthesized polymers can be useful in the application of metal and biological sensors.Singapore-MIT Alliance (SMA

    Synthesis, Optical properties and Applications of Water Soluble Conjugated PPPs for Biosensors

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    In recent years, application of fluorescent conjugated polymers to sense chemical and biological analytes has received much attention owing to its technological significance. Water soluble conjugated polymers are interesting towards the developing sensors for biomolecules. In this present contribution, we describe the syntheses and characterization of a series of water soluble conjugated polymers with sulfonic acid groups in the side chain. Such anionic conjugated polymers are designed to interact with biomolecules such as cytochrome-C. All polymers are water soluble and showed strong blue emission. Significant quenching of the fluorescence from our functionalized PPP was observed upon addition of viologen derivatives or cytochrome -C.Singapore-MIT Alliance (SMA

    Molecular Engineering of Amphiphilic Pyridine Incorporated Conjugated Polymers for Metal Ion Sensors

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    Recent developments in the synthesis and structure-property investigation studies of conjugated polymers have led to the design of novel polymeric materials with tailored properties for advanced technological applications. A promising development in this direction involves the fabrication of conducting polymer based sensors for the detection of metal ions and small organic molecules. Herein, we designed, synthesized and studied a series of amphiphilic copolymers containing alternate phenylene and 2,5- or 2,6- or 3,5-substituted pyridine rings. The basic N-atom of the pyridine ring and the adjacent –OH group from the phenyl ring provide binding sites for metal ions. Thermal properties, and optical properties of polymers in presence of acid, base and metal ions are investigated. A few target polymers showed high sensitivities for metal ions in solution.Singapore-MIT Alliance (SMA

    Autologous/Allogeneic Hematopoietic Cell Transplantation versus Tandem Autologous Transplantation for Multiple Myeloma: Comparison of Long-Term Postrelapse Survival

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    We compared postrelapse overall survival (OS) after autologous/allogeneic (auto/allo) versus tandem autologous (auto/auto) hematopoietic cell transplantation (HCT) in patients with multiple myeloma (MM). Postrelapse survival of patients receiving an auto/auto or auto/allo HCT for MM and prospectively reported to the Center for International Blood and Marrow Transplant Research between 2000 and 2010 were analyzed. Relapse occurred in 404 patients (72.4%) in the auto/auto group and in 178 patients (67.4%) in the auto/allo group after a median follow-up of 8.5 years. Relapse occurred before 6 months after a second HCT in 46% of the auto/allo patients, compared with 26% of the auto/auto patients. The 6-year postrelapse survival was better in the auto/allo group compared with the auto/auto group (44% versus 35%; P = .05). Mortality due to MM was 69% (n = 101) in the auto/allo group and 83% (n = 229) deaths in auto/auto group. In multivariate analysis, both cohorts had a similar risk of death in the first year after relapse (hazard ratio [HR], .72; P = .12); however, for time points beyond 12 months after relapse, overall survival was superior in the auto/allo cohort (HR for death in auto/auto =1.55; P = .005). Other factors associated with superior survival were enrollment in a clinical trial for HCT, male sex, and use of novel agents at induction before HCT. Our findings shown superior survival afterrelapse in auto/allo HCT recipients compared with auto/auto HCT recipients. This likely reflects a better response to salvage therapy, such as immunomodulatory drugs, potentiated by a donor-derived immunologic milieu. Further augmentation of the post-allo-HCT immune system with new immunotherapies, such as monoclonal antibodies, checkpoint inhibitors, and others, merit investigation

    Application of Image Processing Techniques for Autonomous Cars

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    This paper aims to implement different image processing techniques that will help to control an autonomous car. A multistage pre-processing technique is used to detect the lanes, street signs, and obstacles accurately. The images captured from the autonomous car are processed by the proposed system which is used to control the autonomous vehicle. Canny edge detection was applied to the captured image for detecting the edges, Also, Hough transform was used to detect and mark the lanes immediately to the left and right of the car. This work attempts to highlight the importance of autonomous cars which drastically increase road safety and improve the efficiency of driving compared to human drivers. The performance of the proposed system is observed by the implementation of the autonomous car that is able to detect and classify the stop signs and other vehicles

    Human personal air pollution clouds in a naturally ventilated office during the COVID-19 pandemic

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    Personal cloud, termed as the difference in air pollutant concentrations between breathing zone and room sites, represents the bias in approximating personal inhalation exposure that is linked to accuracy of health risk assessment. This study performed a two-week field experiment in a naturally ventilated office during the COVID-19 pandemic to assess occupants’ exposure to common air pollutants and to determine factors contributing to the personal cloud effect. During occupied periods, indoor average concentrations of endotoxin (0.09 EU/m3), TVOC (231 μg/m3), CO2 (630 ppm), and PM10 (14 μg/m3) were below the recommended limits, except for formaldehyde (58 μg/m3). Personal exposure concentrations, however, were significantly different from, and mostly higher than, concentrations measured at room stationary sampling sites. Although three participants shared the same office, their personal air pollution clouds were mutually distinct. The mean personal cloud magnitude ranged within 0–0.05 EU/m3, 35–192 μg/m3, 32–120 ppm, and 4–9 μg/m3 for endotoxin, TVOC, CO2, and PM10, respectively, and was independent from room concentrations. The use of hand sanitizer was strongly associated with an elevated personal cloud of endotoxin and alcohol-based VOCs. Reduced occupancy density in the office resulted in more pronounced personal CO2 clouds. The representativeness of room stationary sampling for capturing dynamic personal exposures was as low as 28% and 5% for CO2 and PM10, respectively. The findings of our study highlight the necessity of considering the personal cloud effect when assessing personal exposure in offices

    Combined influence of oceanic and atmospheric circulations on Greenland sea ice concentration

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    The amount and spatial extent of Greenland Sea (GS) ice are primarily controlled by the sea ice export across the Fram Strait (FS) and by local seasonal sea ice formation, melting, and sea ice dynamics. In this study, using satellite passive microwave sea ice observations, atmospheric and a coupled ocean-sea ice reanalysis system, TOPAZ4, we show that both the atmospheric and oceanic circulation in the Nordic Seas (NS) act in tandem to explain the SIC variability in the south-western GS. Northerly wind anomalies associated with anomalously low sea level pressure (SLP) over the NS reduce the sea ice export in the south-western GS due to westward Ekman drift of sea ice. On the other hand, the positive wind stress curl strengthens the cyclonic Greenland Sea Gyre (GSG) circulation in the central GS. An intensified GSG circulation may result in stronger Ekman divergence of surface cold and fresh waters away from the south-western GS. Both of these processes can reduce the freshwater content and weaken the upper-ocean stratification in the south-western GS. At the same time, warm and saline Atlantic Water (AW) anomalies are recirculated from the FS region to the south-western GS by a stronger GSG circulation. Under weakly stratified conditions, enhanced vertical mixing of these subsurface AW anomalies can warm the surface waters and inhibit new sea ice formation, further reducing the SIC in the south-western GS.publishedVersio
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