Microdevices for separation, accumulation, and analysis of biological micro- and nanoparticles

Microfabrication and performance of a novel microsystem for separation, accumulation and analysis of biological micro- and nanoparticles is reported. Versatile chip functions based on dielectrophoresis and microfluidics were integrated to isolate particles from complex sample solutions such as serum. A bead-based assay for virus detection is proposed. Separation of micro- and sub-mum beads employing dielectrophoretic deflector and bandpass structures is demonstrated. Individual antibody coated beads with hepatitis A virus bound to their surface were trapped by negative dielectrophoresis in a field cage and analysed by fluorescence microscopy.     

Cu materials—From crystal chemistry to magnetic model compounds

Based on electronic structure calculations within the density functional theory, we report a systematic approach for the modelling of low-dimensional Cu^II materials. Combining concepts of crystal chemistry with ab initio-based magnetic models, we present a systematic study of recently discovered compounds. Our calculation results are in good agreement with thermodynamic and magnetic measurements, suggesting the presented approach as a well-directed route to explore the magnetic phase diagram of low-dimensional Cu^II systems.     

Industrial model predictive control technology as applied to continuous polymerization processes

This paper will review the progress to date concerning the application of the new Model Predictive Control (MPC) tools to a prototype continuous polymerization (CP) process. It will discuss in general why the MPC technology maybe a good fit for the CP control problems (minimize settling time after transition, multivariable interactions, unusual process dynamics). It will also discuss our experience with these tools.     

Joint VSB terrestrial digital TV indoor reception project

The reliability and efficacy of indoor reception of 8VSB digital terrestrial television (DTV) in four major U.S. cities was studied in an initial field measurement survey program and a subsequent data capture and processing program. Measurements from the initial survey identified problem sites for reliable DTV reception using currently available 2nd generation DTV receivers. Subsequent field dual channel data captures made at the identified problem sites provided data for testing and verification of new antenna diversity receiver algorithms destined for future generation DTV receivers. From data captures at selected problem sites of sufficient signal strength, but where currently available 2nd generation DTV receivers failed, it was found that in 70% of the cases DTV reception performance was satisfactory when using new antenna diversity receiver algorithms. These measurements and data captures corroborate the claim that the VSB DTV indoor reception problem may be less severe than implied from surveys using less advanced current 2nd generation receivers with a single antenna. For sites with severe multipath, 8VSB DTV reception could be potentially superior to NTSC, which would experience an unwatchable picture.     

The performance of antenna amplifiers used for terrestrial DTV reception

Measurements were made on currently available commercial antenna-mounted amplifiers to ascertain their effects on DTV reception. Data regarding amplifier gain and noise figure is presented, followed by data illustrating the effects of intermodulation within the tested amplifiers as shown by the change in the D/U interference ratio of a control DTV receiver, and ending with observations regarding amplifier environmental sensitivity. Also presented are the inconsistencies between the performance of commercially available amplifiers, advertised to the public for use with television, and the performance claims made by the manufacturers of such amplifiers.     

Topological Quantum Phase Transition and Superconductivity Induced by Pressure in the Bismuth Tellurohalide BiTeI

A pressure‐induced topological quantum phase transition has been theoretically predicted for the semiconductor bismuth tellurohalide BiTeI with giant Rashba spin splitting. In this work, evolution of the electrical transport properties in BiTeI and BiTeBr is investigated under high pressure. The pressure‐dependent resistivity in a wide temperature range passes through a minimum at around 3 GPa, indicating the predicted topological quantum phase transition in BiTeI. Superconductivity is observed in both BiTeI and BiTeBr, while resistivity at higher temperatures still exhibits semiconducting behavior. Theoretical calculations suggest that superconductivity may develop from the multivalley semiconductor phase. The superconducting transition temperature, T_c, increases with applied pressure and reaches a maximum value of 5.2 K at 23.5 GPa for BiTeI (4.8 K at 31.7 GPa for BiTeBr), followed by a slow decrease. The results demonstrate that BiTeX (X = I, Br) compounds with nontrivial topology of electronic states display new ground states upon compression.     

A New Highly Anisotropic Rh-Based Heusler Compound for Magnetic Recording

The development of high-density magnetic recording media is limited by superparamagnetism in very small ferromagnetic crystals. Hard magnetic materials with strong perpendicular anisotropy offer stability and high recording density. To overcome the difficulty of writing media with a large coercivity, heat-assisted magnetic recording was developed, rapidly heating the media to the Curie temperature T_c before writing, followed by rapid cooling. Requirements are a suitable T_c, coupled with anisotropic thermal conductivity and hard magnetic properties. Here, Rh₂CoSb is introduced as a new hard magnet with potential for thin-film magnetic recording. A magnetocrystalline anisotropy of 3.6 MJ m⁻³ is combined with a saturation magnetization of μ₀M_s = 0.52 T at 2 K (2.2 MJ m⁻³ and 0.44 T at room temperature). The magnetic hardness parameter of 3.7 at room temperature is the highest observed for any rare-earth-free hard magnet. The anisotropy is related to an unquenched orbital moment of 0.42 μ_B on Co, which is hybridized with neighboring Rh atoms with a large spin–orbit interaction. Moreover, the pronounced temperature dependence of the anisotropy that follows from its T_c of 450 K, together with a thermal conductivity of 20 W m⁻¹ K⁻¹, make Rh₂CoSb a candidate for the development of heat-assisted writing with a recording density in excess of 10 Tb in.⁻².     

A cost and value analysis of two interventions with incontinent nursing home residents

OBJECTIVE: More than half of nursing home residents suffer from urinary incontinence. These residents typically have long stays and, because of comorbid cognitive and physical impairments, have little hope of living again in a noninstitutional environment The value of interventions to change functional status of this chronically institutionalized population is often questioned. This paper explores this value issue in the context of two incontinence management interventions that have been shown to improve functional status: (1) Functional Incidental Training (FIT), and (2) Prompted Voiding (PV). The relative value of the different interventions for the nursing home population was estimated using paired preferences. DESIGN: The cost of two interventions (FIT and PV) that target incontinent nursing home residents was related to the value of these interventions as perceived by consumers of nursing home services. Both interventions decrease incontinence frequency, and one intervention also improves mobility endurance. PARTICIPANTS: Ninety incontinent nursing home residents received the intervention; 37 older nondemented board and care residents and 31 family members of the nursing home residents provided estimates of the intervention's value. MEASUREMENT: The staff-time allocations involved in implementing both interventions were documented in more than 85 resident care episodes. These time data were converted to labor cost based on the cost of nursing aides who would actually implement the intervention. The value of each intervention was assessed by asking consumers to make choices between the intervention and its associated outcomes (such as increased dryness) and other nursing home services of known cost (e.g., moving to a private room). RESULTS: Both interventions had labor costs that were greater than "usual care" costs. The additional cost was estimated to be $4.31 per resident per day for PV and $6.42 per resident per day for FIT if these programs were implemented from 7 AM to 7 AM. Consumer preference data indicated that consumers preferred the FIT and PV outcomes to more expensive alternative services, calculated to cost $10.00 per day, often marketed to consumers, CONCLUSION: Consumers may prefer the FIT and PV interventions relative to the typical services often marketed to the nursing home consumer. The analysis completed in this paper suggests that both interventions have value for frail residents likely to live out their lives in a nursing home.     

Size-dependent structural and magnetic properties of chemically synthesized Co-Ni-Ga nanoparticles

Phase transitions and magnetic properties of shape-memory materials can be tailored by tuning the size of the constituent materials,such as nanoparticles.However,owing to the lack of suitable synthetic methods for size-controlled Heusler nanoparticles,there is no report on the size dependence of their properties and functionalities.In this contribution,we present the first chemical synthesis of size-selected Co-Ni-Ga Heusler nanoparticles.We also report the structure and magnetic properties of the biphasic Co-Ni-Ga nanoparticles with sizes in the range of 30-84 nm,prepared by a SBA-15 nanoporous silicatemplated approach.The particle sizes could be readily tuned by controlling the loading and concentration of the precursors.The fractions and crystallite sizes of each phase of the Co-Ni-Ga nanoparticles are closely related to their particle size.Enhanced magnetization and decreased coercivity are observed with increasing partide size.The Curie temperature (Tc) of the Co-Ni-Ga nanoparticles also depends on their size.The 84 nm-sized particles exhibit the highest Tc (≈ 1,174 K) among all known Heusler compounds.The very high Curie temperatures of the Co-Ni-Ga nanoparticles render them promising candidates for application in high-temperature shape memory alloy-based devices.