Association between PDCD1 Gene Polymorphisms and Risk of Systemic Lupus Erythematosus in Three Main Ethnic Groups of the Malaysian Population

The programmed cell death 1 (PDCD1) gene encodes for the PD-1 (programmed death 1) molecule, which negatively regulates self-reactive T- and B-cells in the maintenance of peripheral tolerance. A previous report had shown the development of lupus-like phenotypes in PD-1-deficient C57BL/6 mice, was suggestive to the role of PDCD1 in predisposing to systemic lupus erythematosus (SLE). Hence, we aimed to investigate the association between PDCD1 and SLE susceptibility in the Malaysian population. A TaqMan-based real-time PCR was employed to screen for PD1.1, PD1.3, PD1.5 and PD1.6 in both SLE and healthy control groups of 200 samples each. The observed frequency for PD1.5C/C genotype was significantly higher in Indian SLE patients and Malay controls (p < 0.01). On the other hand, the PD1.5C/T genotype might predispose the Malays to SLE, but confer a protective effect among the Indians (p < 0.01). The PD1.1, PD1.3 and PD1.6 were, however, not correlated to genetic predisposition of SLE in our Malaysian population. In conclusion, PD1.5 variant was significantly associated to SLE susceptibility in our Malaysian cohort. Our failure in replicating the association between other investigated PDCD1 variants and risk of getting SLE might due to ethnic and geographic variations in the distribution of these genetic variants.     

Physics of Silicene Stripes

Silicene, a monolayer of silicon atoms tightly packed into a two-dimensional honeycomb lattice, is the challenging hypothetical reflection in the silicon realm of graphene, a one-atom thick graphite sheet, presently the hottest material in condensed matter physics. If existing, it would also reveal a cornucopia of new physics and potential applications. Here, we reveal the epitaxial growth of silicene stripes self-aligned in a massively parallel array on the anisotropic silver (110) surface. This crucial step in the silicene “gold rush” could give a new kick to silicon on the electronics road-map and open the most promising route towards wide-ranging applications. A hint of superconductivity in these silicene stripes poses intriguing questions related to the delicate interplay between paired correlated fermions, massless Dirac fermions and bosonic quasiparticles in low dimensions.     

Robust stabilization of uncertain impulsive switched systems with delayed control

In this paper, stability criteria and switching controllers’ design problems for uncertain impulsive switched systems with input delay are investigated by using the receding horizon method. Some LMI conditions are derived to guarantee asymptotical stability of an impulsive switched system under a certain designed delayed controller. Finally, a numerical example is presented to illustrate the effectiveness of the results obtained.     

An integrated optimal control algorithm for discrete-time nonlinear stochastic system

Consider a discrete-time nonlinear system with random disturbances appearing in the real plant and the output channel where the randomly perturbed output is measurable. An iterative procedure based on the linear quadratic Gaussian optimal control model is developed for solving the optimal control of this stochastic system. The optimal state estimate provided by Kalman filtering theory and the optimal control law obtained from the linear quadratic regulator problem are then integrated into the dynamic integrated system optimisation and parameter estimation algorithm. The iterative solutions of the optimal control problem for the model obtained converge to the solution of the original optimal control problem of the discrete-time nonlinear system, despite model-reality differences, when the convergence is achieved. An illustrative example is solved using the method proposed. The results obtained show the effectiveness of the algorithm proposed.     

A suboptimal feedback control for nonlinear time-varying systems with continuous inequality constraints

A feedback control law, which is constructed as a first-order approximation to the optimal control, is proposed for nonlinear time-varying systems subject to continuous inequality constraints on the control and state. This control law is effective under small state perturbations caused by changes on initial conditions and/or modeling uncertainty.     

Optimal control for zinc solution purification based on interacting CSTR models

In zinc solution purification process, zinc dust is used to remove impurity ions in several serial stirred tank reactors. It is modelled by using several interacting continuously stirred tank reactor (ICSTR) systems with multiple time delays. Some unknown parameters of the ICSTR model are identified based on experimental data collected from a zinc production factory in China. Then a time delayed optimal control problem with continuous inequality constraints is constructed for the zinc solution purification. A numerical computational algorithm is developed, based on the control parameterization method, to design an optimal control law to ensure that a sufficiently low level of effluent impurities is achieved with the least zinc dust consumption. Finally, numerical simulation is carried out. The results obtained indicate that the effect of the optimal control for zinc solution purification is highly satisfactory.     

Constraint feedforward control for thermal processing of quartz photomasks in microelectronics manufacturing

A feedforward control scheme is designed to improve performance of conductive heating systems used for lithography in microelectronics processing. It minimizes the loading effects induced by the common processing condition of placement of a quartz photomask at ambient temperature on a bake plate at processing temperature. The feedforward control strategy is a model-based method using linear programming to minimize the worst-case deviation from a nominal temperature set-point during the load disturbance condition. This results in a predictive controller that performs a pre-determined heating sequence prior to the arrival of the substrate as part of the resulting feedforward/feedback strategy to eliminate the load disturbance. This procedure is based on an empirical model generated from data obtained during closed-loop operation. It is easy to design and implement for conventional thermal processing equipment. Experimental results are performed for two commercial bake plates and depict an order-of-magnitude improvement in the settling time and the integral-square temperature error between the optimal predictive controller and a feedback controller for a typical load disturbance.     

Spray dried solid dispersions of piroxicam in carboxymethyl sago cellulose using aqueous solvents: A simple,novel and green approach to produce enteric microparticles with enhanced dissolution

Piroxicam-CMSC solid dispersions were produced by spray drying from aqueous solvents. Depending on the drug-polymer ratio, loading and entrapment efficiency of CMSC microparticles were 6.8–46.75 and 40.79–60.35% w/w, respectively. Scanning electron microscopy revealed non-spherical geometry and agglomeration of the spray-dried particles. The average size of the particles ranged from 7 to 170?µm. Infrared spectroscopy, differential scanning calorimetry, and X-ray diffraction confirmed intact crystalline piroxicam in the microparticles. In gastric pH, microparticles and native piroxicam have shown less than 25% and more than 45% of drug dissolution, respectively in 2?h. In contrast, at pH 7.4, microparticles have shown 80% of drug dissolution; whereas native piroxicam achieved only 30% of dissolution by 30?min. The spray-dried CMSC particles are efficient in restricting drug release in gastric pH and enhance drug dissolution in intestinal pH. The method is eco-friendly as it uses aqueous solvents and non-toxic materials.