A Leakage-Based Precoding Scheme for Downlink Multi-User MIMO Channels

In multiuser MIMO downlink communications, it is necessary to design precoding schemes that are able to suppress co-channel interference. This paper proposes designing precoders by maximizing the so-called signal-to-leakage-and-noise ratio (SLNR) for all users simultaneously. The presentation considers communications with both single- and multi-stream cases, as well as MIMO systems that employ Alamouti coding. The effect of channel estimation errors on system performance is also studied. Compared with zero-forcing solutions, the proposed method does not impose a condition on the relation between the number of transmit and receive antennas, and it also avoids noise enhancement. Simulations illustrate the performance of the scheme     

Digital adaptive phase noise reduction in coherent optical links

Coherent optical links enable high-density constellations and, consequently, a higher throughput. However, the phase noise associated with the transmitter and the receiver lasers is a challenging issue in coherent lightwave systems. The authors present an approach that relies on using digital signal processing techniques to compensate for the laser phase-noise effects. The proposed approach exploits the digital processing power to address the problems arising from optical imperfections. The authors present an adaptive filtering scheme that reduces the effect of the laser phase noise and, consequently, relaxes the laser linewidth requirement. The proposed approach shows how the signal processing techniques can be exploited to compensate for the optical impairments by utilizing the continuing scale down in size and power in very large scale integration (VLSI) technology.     

Overcoming Microenvironment-Mediated Chemoprotection through Stromal Galectin-3 Inhibition in Acute Lymphoblastic Leukemia

Environmentally-mediated drug resistance in B-cell precursor acute lymphoblastic leukemia (BCP-ALL) significantly contributes to relapse. Stromal cells in the bone marrow environment protect leukemia cells by secretion of chemokines as cues for BCP-ALL migration towards, and adhesion to, stroma. Stromal cells and BCP-ALL cells communicate through stromal galectin-3. Here, we investigated the significance of stromal galectin-3 to BCP-ALL cells. We used CRISPR/Cas9 genome editing to ablate galectin-3 in stromal cells and found that galectin-3 is dispensable for steady-state BCP-ALL proliferation and viability. However, efficient leukemia migration and adhesion to stromal cells are significantly dependent on stromal galectin-3. Importantly, the loss of stromal galectin-3 production sensitized BCP-ALL cells to conventional chemotherapy. We therefore tested novel carbohydrate-based small molecule compounds (Cpd14 and Cpd17) with high specificity for galectin-3. Consistent with results obtained using galectin-3-knockout stromal cells, treatment of stromal-BCP-ALL co-cultures inhibited BCP-ALL migration and adhesion. Moreover, these compounds induced anti-leukemic responses in BCP-ALL cells, including a dose-dependent reduction of viability and proliferation, the induction of apoptosis and, importantly, the inhibition of drug resistance. Collectively, these findings indicate galectin-3 regulates BCP-ALL cell responses to chemotherapy through the interactions between leukemia cells and the stroma, and show that a combination of galectin-3 inhibition with conventional drugs can sensitize the leukemia cells to chemotherapy.     

Ultra-low power inductorless differential LNA for WSN application

Analog Integrated Circuits and Signal Processing - In this paper, a wide band inductorless differential low noise amplifier (LNA) is designed and analyzed. To attain ultra-low power consumption,...     

Design and Implementation of a Baseband WCDMA Dual-Antenna Mobile Terminal

The design and implementation of a baseband wide-band code-division multiple access (WCDMA) dual-antenna mobile terminal system-on-a-chip (SoC) is presented in this paper. Spatial diversity processing mitigates wireless channel impairments and is a key enabling technology for WCDMA to support high quality of service at high data rates and capacity. The SoC integrates the baseband transceiver, coding and decoding functions, microcontrollers to implement the radio access protocols, and external interfaces to communicate with the application layer. The receiver design, which takes advantage of diversity benefits in several blocks, is described in detail. The SoC was fabricated in a 0.18-mum 1.8-V CMOS technology and requires a total area of 72mm² consuming 532 mW at the maximum data rates. The application-specific integrated circuit was used in lab testing where a gain of up to 9 dB was observed for the dual-antenna receiver, which demonstrates the tremendous improvement provided by spatial diversity. The results presented in this paper provide a base architecture and a performance benchmark for commercial implementations of WCDMA mobile terminals     

Active Antenna Selection in Multiuser MIMO Communications

The paper develops a dynamic antenna scheduling strategy for downlink MIMO communications, where a subset of the receive antennas at certain users is selectively disabled. The proposed method improves the signal-to-leakage-plus-noise (SLNR) ratio performance of the system and it relaxes the condition on the number of transmit-receive antennas in comparison to traditional zero-forcing and time-scheduling strategies. The largest value that the SLNR can achieve is shown to be equal to the maximum eigenvalue of a certain random matrix combination, and the probability distribution of this eigenvalue is characterized in terms of a Whittaker function. The result shows that increasing the number of antennas at some users can degrade the SLNR performance at other users. This fact is used to propose an antenna scheduling scheme that leads to improvement in terms of SINR outage probabilities     

Chemometrics-Enhanced Micelle-Mediated Extraction Spectrophotometric Method for Simultaneous Determination of Cu<Superscript>2+</Superscript> and Zn<Superscript>2+</Superscript> in Medicinal Plant,Rice and Water Samples Using Continuous Wavelet Transform

A new micelle-mediated extraction method for the pre-concentration of trace amounts of Cu²⁺ and Zn²⁺ as a prior step to their simultaneous spectrophotometric determination has been developed in various samples. The analytes were complexed with new synthesized ligand 4,4′-((4-chlorophenyl)methylene)bis(1,3-diphenyl-1H-pyrazol-5-ol) (CPBMPY) and Triton X-100 was added as a extraction agent. The optimal reaction and extraction conditions were optimized and the analytical characteristics of the method were obtained. The detection limit of the method was 0.90 and 0.30 ng mL^?1 for Cu²⁺ and Zn²⁺, respectively. Continuous wavelet transformation (CWT) of visible spectra as a very simple and accurate method was developed for the simultaneous determination of binary mixtures of Cu²⁺ and Zn²⁺ ions. A zero-crossing technique was applied on the transformed signals and the constructed calibrations were tested by analyzing the composition of the different binary mixtures. The proposed procedure successfully was applied to analysis of water, rice, and medicinal plant and reference material samples. The amounts of metal ions obtained by the proposed methods were in good agreement with those obtained by Graphite furnace atomic absorption spectrometry.     

Molecular dynamics simulation to assess the effect of temperature on diffusion coefficients of different ions and water molecules in C-S-H

Diffusion is a particle transportation process beginning from one point of a system to another through random molecular motion. This process depends on various parameters like temperature, concentration gradient, and particle size. The objective of this article is to assess the variation of diffusion coefficients of water molecules, chloride and sodium ions against different temperatures in calcium silicate hydrates (C-S-H) through molecular dynamics simulation. A uniform sodium chloride solution is modeled between cement hydrate layers with no concentration gradient. In such a solution, temperature could affect diffusion process in a significant manner. The two most important crystalline mineral analogues of C-S-H, tobermorite and jennite, are applied in this simulation. Diffusion coefficients of different ions and water molecules are found in different temperatures. It is revealed that diffusion coefficient is higher at high temperatures. Activation energies of chloride and sodium ions transport in cement hydrates are calculated through Arrhenius law. Output values of diffusion coefficients and activation energies are compared to previous experimental and simulation results in the related literature. A multi-scale analysis is run to estimate the penetration depth of \(\mbox{Cl}^{-}\) ions in cement paste through Fick’s second law.     

Bioassay Development for Bispecific Antibodies—Challenges and Opportunities

Antibody therapeutics are expanding with promising clinical outcomes, and diverse formats of antibodies are further developed and available for patients of the most challenging disease areas. Bispecific antibodies (BsAbs) have several significant advantages over monospecific antibodies by engaging two antigen targets. Due to the complicated mechanism of action, diverse structural variations, and dual-target binding, developing bioassays and other types of assays to characterize BsAbs is challenging. Developing bioassays for BsAbs requires a good understanding of the mechanism of action of the molecule, principles and applications of different bioanalytical methods, and phase-appropriate considerations per regulatory guidelines. Here, we review recent advances and case studies to provide strategies and insights for bioassay development for different types of bispecific molecules.