An investigation of liquid carryover and sample residual for a high-throughput flow cytometer sample delivery system

The phenomenon of intersample contamination in air-segmented continuous-flow assays has been studied for many years, and new uses are being found for these sampling techniques every day. One application that has been developed recently employs a flow cytometer to conduct high-throughput screening assays of biological compounds. We have explored the sources of intersample contamination in the system and shown how methods developed previously can be applied to describe these phenomena. Using a simple model, we were able to accurately measure liquid film thickness in the sample tubing and demonstrate the effects of intersample contamination in a flow cytometer assay. Also, measures have been taken to reduce the level of intersample contamination in cytometric screening assays, helping to make the system a more viable tool for drug screening applications.     

Sum of arbitrarily correlated Gamma variates and performance of wireless communication systems over Nakagami-m fading channels

The probability density function (PDF) and the moment generating function (MGF) of a sum of squares of arbitrarily correlated, non-identically distributed Nakagami-m random variates, with non-identical and non-integer fading orders are derived. The authors proposed a simple method to determine a good truncation of the PDFs infinite sum and the associated truncation error. The derived results can be used to analyse a number of performance measures of diversity combining techniques in wireless communication systems over Nakagami-m fading channels.     

Ozone-mediated polyol synthesis from soybean oil

Polyols from vegetable oils can replace petroleumbased polyols in the preparation of polyurethanes and polyesters in a wide range of applications. However, previous preparation methods are either too costly, inefficient, or yield secondary alcohols, which are less reactive than the desired primary alcohols. The objectives of this study were to prepare primary soy-based polyols by a new catalytic ozonolysis process and to characterize the composition of the product mixture. In this new process, the polyols were prepared by passing ozone through a solution of soybean oil and ethylene glycol in the presence of an alkaline catalyst. Unlike conventional ozonolysis that yields aldehydes and carboxylic acids by spontaneous decomposition of the ozonide intermediates, the ozonides in our method reacted with the hydroxyl group of the glycol to form an ester linkage with a terminal hydroxy group. Statistical analysis of the product mixture indicates that the resulting polyol mixture is more uniform than the original TG mixture, having (2-hydroxy)nonanoate as the major component of the new hydroxyl functional TG. The chemical structure of the polyols produced was further characterized by iodine number and ¹³C NMR and FTIR spectroscopy, which confirmed the cleavage of the double bonds, the presence of hydroxyl groups, and the formation of new ester linkages.     

Deep,Landmark-Free FAME: Face Alignment,Modeling, and Expression Estimation

International Journal of Computer Vision - We present a novel method for modeling 3D face shape, viewpoint, and expression from a single, unconstrained photo. Our method uses three deep...     

Secure communication in untrusted relay selection networks with wireless energy harvesting

In this paper, we consider the secrecy performance of an energy-harvesting relaying system with Kth best partial relay selection where the communication of a multi-antenna source-destination pair is assisted via single-antenna untrusted relays. To protect confidential source messages from untrusted relays, transmit beamforming and destination jamming signals are used. The relays are energy-constrained nodes that use the power-splitting policy to harvest energy through the wireless signals from both the source and destination. For performance evaluation, closed-form expressions of the secrecy outage probability and average secrecy capacity (ASC) are derived for Nakagami-m fading channels. The analytical results are confirmed via Monte Carlo simulations. Numerical results provide valuable insights into the effect of various system parameters, such as relay location, number of relays, and power splitting ratio, on the secrecy performance. Specifically, the maximum ASC is achieved when the relay is located between the source and destination.

     

D.C. optimization approach to robust control: Feasibility problems

The feasibility problem for constant scaling in output feedback control is considered. This is an inherently difficult problem since the set of feasible solutions is non-convex and may be disconnected. Nevertheless, we show that this problem can be reduced to the global minimization of a concave function over a convex set, or alternatively, to the global minimization of a convex program with an additional reverse convex constraint. Thus this feasibility problem belongs to the realm of d.c. optimization, a new field which has recently emerged as an active promising research direction in nonconvex global optimization. By exploiting the specific d.c. structure of the problem, several algorithms are proposed which at every iteration require solving only either convex or linear subproblems. Analogous algorithms with new characterizations are proposed for the bilinear matrix inequality (BMI) feasibility problem.     

Preparation of Al2O3–AlN–Ni Composites

A method is proposed to prepare Al₂O₃-AlN-Ni composites. The composites are prepared by sintering Al₂O₃/NiAl powder mixtures at 1600°C in a mixture of nitrogen and carbon monoxide. The presence of NiAl particles raises the green density of Al₂O₃/NiAl powder compacts. During sintering, NiAl reacts with nitrogen to form AlN and Ni inclusions. A volume expansion accompanies the reaction. Because of the high green density and the reaction, the volume shrinkage of the Al₂O₃-AlN-Ni composite decreases with the increase of added NiAl content.     

Novel regioregular poly(3-hexylthiophene)-based polycationic block copolymers

Regioregular poly(3-hexylthiophene) has been successfully incorporated into various poly(N,N-dimethylamino-2-ethyl methacrylate)-based block copolymers, i.e., P3HT-b-PDMAEMA, via Grignard metathesis (GRIM) method and atom transfer radical polymerization (ATRP) reactions. The structure of the diblock copolymers was fully confirmed by FT-IR, ¹H NMR spectroscopy, gel permeation chromatography (GPC), and ultraviolet–visible spectroscopy (UV–vis). The recovered copolymers could be treated by protonation of the pending tertiary amine functions and depending on the relative content in PDMAEMA, the copolymers could be solubilized in more polar solvents where P3HT alone proved to be totally insoluble.     

Determination of a unique configuration of free-form tensegrity structures

A numerical method is presented for form-finding of free-form tensegrity structures. The topology and an initial randomly generated force density vector are the required information in the present form-finding process. An approach of defining a unique configuration of free-form tensegrity structures by specifying an independent set of nodal coordinates is rigorously provided, which means that the geometrical and mechanical properties of the structure can be at least partly controlled by the proposed method. Several numerical examples are presented to demonstrate the efficiency and robustness in searching new self-equilibrium stable free-form configurations of tensegrity structures.