Feasibility of TEOS coated CoFe2O4 nanoparticles to a GMR biosensor agent for single molecular detection

Magnetic properties of 200 nm ferrimagnetic CoFe2O4 nanoparticles before and after coating with TEOS were explored and compared to soft ferrimagnetic MgFe2O4 nanoparticles (200 nm) to evaluate the feasibility as an in-vitro GMR SV (giant magnetoresistance spin-valve) biosensor agent for single molecular detection (SMD). It was found that the magnetic degradation (or variation) of TEOS coated CoFe2O4 and MgFe2O4 nanoparticles are dominantly affected by the chemical dispersion process, which is carried out in the oleic acid (OA), oleylamine (OL), or OA+OL surfactant, before starting major coating process. In addition, the TEOS coating thickness controlled by TEOS concentration and pH level in the buffer solution prominently influenced on the magnetic degradation of TEOS coated nanoparticles. According to the experimental analysis results, the magnetic degradation of TEOS coated nanoparticles is mainly attributed to the variation of particle dipole interaction caused by the degree of particle aggregation depending on TEOS coating process conditions. The TEOS coated CoFe2O4 nanoparticles exhibited a higher magnetic stability for a GMR biosensor agent, e.g., small variation of remnant magnetization, saturation magnetization and magnetic coercivity, than that of MgFe2O4 nanoparticles at the different coating process conditions. The physical and chemical analysis confirmed that this is primarily due to its higher magnetic anisotropy. The experimentally verified high biocompatibility as well as the stably maintained magnetic properties of TEOS coated CoFe2O4 nanoparticles demonstrate that CoFe2O4 nanoparticles can be considered as one of the promising ferrimagnetic nanoparticle sensor agent for an SMD GMR SV biosensor.     

On-Site diagnostic device based on immuno-separation of proteins

A membrane immuno-chromatographic system that selectively separates plasma lipoproteins and generates a signal in proportion to the concentration of cholesterol (HDL-C) within high-density lipoprotein (HDL) was investigated as a point-of-care device for the prognosis of coronary heart disease. The system consists of three functional membrane strip pads connected in a sequence for: (from the bottom) immuno-separation based on biotinstreptavidin reaction, catalytic conversion of cholesterol to hydrogen peroxide, and production of a signal. For immunochromatography, a monoclonal antibody, specific to apolipoprotein B100 that is present on the surfaces of low-density lipoproteins (LDL) and very low-density lipoproteins (VLDL), with a high binding constant (5xl0¹⁰ L/mol) was raised and chemically conjugated to streptavidin. The conjugate was first reacted with lipoprotein particles, and this mixture was absorbed by the capillary action into the biotin pad of the system. After being transferred by medium, immunocapture of LDL and VLDL particles onto the biotin pad took place, andin situ generation of a signal in proportion to HDL-C consecutively occurred. The capture was selective as well as effective (minimum 90% of LDL and VLDL in clinical concentration ranges), and the detection limit of HDL-C was far lower than 20 mg/dL. To construct a userfriendly device, we are currently investigating the automation of such processes of reactions and separation by adapting a liquid flow-controlling technology that programs the times for the immune reaction and separation. My group further pursues an interdisciplinary study to develop a micro system employing semiconductor-based technologies that will eventually enable the handling of sub-micro liter volume of body fluid as a specimen.     

Evaluation of standing-wave thermoacoustic cycles for cooling applications

The most promising applications for standing-wave thermoacoustic cooling were investigated from the perspective of the ratio of coefficient of performance (COP) to the reversible COP or COPR. A design optimization program based on the thermoacoustic simulation program known as DELTAE was developed. The program was applied to two standing-wave thermoacoustic cooler configurations in order to determine the best possible COPRs for various temperature spans between hot-side and cold-side stack-end temperatures. It was found that the COPR of standing-wave thermoacoustic coolers increases with temperature span and reaches a maximum for temperature lifts around 80 °C. Analysis of the results and the losses clearly shows that the efficiency of these systems may be good for refrigeration, but not for air-conditioning and cryogenic cooling. The COPRs determined from measurements for various thermoacoustic coolers developed so far show similar trends, and generally support the optimization results.     

Enhanced contrast of electrochromic full cell systems with nanocrystalline PEDOT-prussian blue

Poly-(3,4-ethylenedioxythiophene) (PEDOT) is an ideal polymer for electrochromic (EC) devices due to its fast response time, high conductivity, and facile fabrication in a doped form except its demerit like an optical contrast limitation. In this study, we developed a simple way to overcome low coloration efficiency of PEDOT through fabricating a complementary PEDOT and prussian blue full cell system. Fundamental properties of EC displays, such as optical contrast, coloration efficiency, and switching speed, could be successfully optimized by controlling the deposition time and applied voltage during EDOT polymerization. In particular, UV transmittance spectra indicated that the optical contrast was enhanced up to 31 approximately 99% at the wavelength of 600 nm. Scanning electron microscopy images showed that the optimized PEDOT and prussian blue films were deposited on ITO glass substrate with an uniform thickness of approximately 180 nm and approximately 190 nm, respectively. Moreover, according to the circuit analysis, the average response time of electric current for the optimized full cell system was about 400 ms. It is, therefore, concluded that such a full cell system could have high potential applications as smart windows and/or optical devices.     

Personalizing influence diagrams: applying online learning strategies to dialogue management

We consider the problem of adapting the parameters of an influence diagram in an online fashion for real-time personalization. This problem is important when we use the influence diagram repeatedly to make decisions and we are uncertain about its parameters. We describe learning algorithms to solve this problem. In particular, we show how to modify various explore-versus-exploit strategies that are known to work well for Markov decision processes to the more general influence-diagram model. As an illustration, we describe how our techniques for online personalization allow a voice-enabled browser to adapt to a particular speaker for spoken dialogue management. We evaluate all the explore-versus-exploit strategies in this domain.     

Monitoring of serologic immune parameters in inflammatory skin diseases

This paper deals with the correlation of clinical scoring and serologic markers of inflammation in atopic dermatitis and psoriasis. Serum eosinophil cationic protein (ECP), soluble interleukin-2 receptor (sIL-2R), total serum IgE, IgG and IgM anti-IgE antibodies, and IgE immune complexes were evaluated in monitoring inflammatory skin diseases such as atopic dermatitis and psoriasis. Well-established clinical activity scores were used as standards in recording skin improvement under treatment in a clinical setting. Serum ECP was found to be increased in both atopic dermatitis and psoriasis patients compared to normal controls; sIL-2R and IgE immune complexes were increased only in atopics with increased serum IgE. Anti-IgE antibodies did not show any deviation in both groups of patients. There was a significant elevation of sIL-2R and IgE immune complexes and a nonsignificant elevation of ECP in high-IgE atopics in comparison to those with normal serum IgE. In both groups of patients, there was a significant reduction of ECP and sIL-2R accompanying the improving skin condition. Serum IgE and the other immune parameters failed to respond. In contrast to other studies, serum ECP failed to correspond significantly with disease activity in our study. Our results showed measurable changes of ECP and sIL-2R for atopic dermatitis and/or psoriasis under treatment, but comparison to clinical scores remains difficult due to the different basis of the two systems. The only significant correlation was established for relative changes in sIL-2R and psoriasis area and intensity (PASI), a correlation which might be a useful approach in psoriasis.     

Improving command and control speech recognition on mobile devices: using predictive user models for language modeling

Command and control (C&C) speech recognition allows users to interact with a system by speaking commands or asking questions restricted to a fixed grammar containing pre-defined phrases. Whereas C&C interaction has been commonplace in telephony and accessibility systems for many years, only recently have mobile devices had the memory and processing capacity to support client-side speech recognition. Given the personal nature of mobile devices, statistical models that can predict commands based in part on past user behavior hold promise for improving C&C recognition accuracy. For example, if a user calls a spouse at the end of every workday, the language model could be adapted to weight the spouse more than other contacts during that time. In this paper, we describe and assess statistical models learned from a large population of users for predicting the next user command of a commercial C&C application. We explain how these models were used for language modeling, and evaluate their performance in terms of task completion. The best performing model achieved a 26% relative reduction in error rate compared to the base system. Finally, we investigate the effects of personalization on performance at different learning rates via online updating of model parameters based on individual user data. Personalization significantly increased relative reduction in error rate by an additional 5%.     

Thermodynamic Relation between Silicon and Aluminum in Liquid Iron

The thermodynamic relation between silicon and aluminum in liquid iron was studied by measuring the effect of silicon on the solubility product of AlN in liquid Fe-Si-Al-N alloys containing silicon up to 1.5?mass pct in the temperature range from 1823?K to 1923?K (1550 °C to 1650 °C). The effects of aluminum and silicon on nitrogen solubility in liquid iron were separately determined in the same temperature range. The experimental results were thermodynamically analyzed using Wagner??s interaction parameter formalism to determine the first-order interaction parameters of silicon on nitrogen and aluminum in liquid iron as follows: $ e_{\text{N}}^{\text{Si}} = 0. 0 6 7 3, \;e_{\text{Al}}^{\text{Si}} = 0.009 $ (1823?K to 1923?K (1550 °C to 1650 °C), Si ?? 1.5?mass pct)     

Holographic CDMA

A new technique for all-optical code division multiple access (CDMA) based on optical holography is described. In this technique the energy of an incoming information light signal is spread over a larger spatial domain by a two-dimensional spatial encoder which consists of patterns of (0, 1) or (1, -1). Subsequent decoding, which is obtained by a holographic filter, spatially despreads the energy of information light signal and brings it to a bright focused light spot. Experimental results obtained to demonstrate the encoding, decoding, and multiaccess capability of the proposed holographic CDMA technique are discussed and compared to other all-optical CDMA techniques. The processing gain for a holographic CDMA can be potentially as high as 10⁶-10⁸ , which suggests that this technique can in principle support hundreds of thousands to a few millions of users     

Mathematical Analysis of Throughput Bounds in Random Access with Z<Emphasis Type=SmallCaps>ig</Emphasis>Z<Emphasis Type=SmallCaps>ag</Emphasis> Decoding

We investigate the throughput improvement that ZigZag decoding (Gollakota and Katabi 2008) can achieve in multi-user random access systems. ZigZag is a recently proposed 802.11 receiver design that allows successful reception of packets despite collision. Thus, the maximum achievable throughput of a wireless LAN can be significantly improved by using ZigZag decoding. We analyze the throughput bounds in four different idealized multi-access system models for the case when ZigZag decoding is used. We also provide results for the Aloha and CSMA models where exact closed form solutions are infeasible to calculate. Our analysis and simulation results show that ZigZag decoding can significantly improve the maximum throughput of the random access system.