Passively driven integrated microfluidic system for separation of motile sperm

This paper describes a self-contained integrated microfluidic system that can separate motile sperm from small samples that are difficult to handle using conventional sperm-sorting techniques. The device isolates motile sperm from nonmotile sperm and other cellular debris, based on the ability of motile sperm to cross streamlines in a laminar fluid stream. The device is small, simple, and disposable yet is an integrated system complete with sample inlets, outlets, sorting channel, and a novel passively driven pumping system that provides a steady flow of liquid; it requires no external power source or controls. The device fulfills a need in clinical settings where small amounts of sperm need to be sorted. It also opens the way for convenient bioassays based on sperm motility including at-home motile sperm tests.     

Characteristics of nanocrystalline AlN:Er films co-deposited by using AlN, Er, and SiO2 targets

We report the characteristics of AlN:Er films that were co-deposited by using AlN, Er, and SiO₂ targets. The PL emission spectra show strong green emissions of Er³⁺ ions in AlN:Er films annealed at an optimal temperature of 750 °C, which is attributed to the intra-4f Er³⁺ transitions of ²H_11/2 → ⁴I_15/2 and ⁴F_7/2 → ⁴I_15/2. This optimal temperature can activate Er species as an efficient visible luminescence center. High-resolution transmission electron microscopy (HREM) observations showed that the AlN:Er film annealed at 750 °C exhibits the microstructure of AlN nanocrystallites embedded in the amorphous matrix. The occurrence of strong Er³⁺ emissions in the amorphous-nanocrystalline AlN:Er films by thermal annealing might contribute to an increased number of excitation Er³⁺ centers and the presence of oxygen related to Er³⁺ excitation and recombination processes. A distinct visible bluish green emission is also confirmed from the EL device with an amorphous-nanocrystalline AlN:Er active layer.     

电动汽车稳定性控制中的车体侧偏角观测器研究

采用轮毂电机独立驱动的电动汽车可采用直接横摆力矩控制(Direct Yaw-moment Control,DYC)等稳定性控制,而车体侧偏角(简称β角)是稳定性控制中的重要参数.直接测定车体侧偏角的传感器相当昂贵,所以需要从能够容易测得的参数来进行车体侧偏角的推测.Hori研究室设计了一种用于β角推测的观测器,并充分考虑了车辆运行工况变化所引起的系统模型参数变化,进行了观测器鲁棒性设计以及轮胎侧偏刚度在线辨识,使观测器具备了足够的鲁棒性来克服大的模型误差影响,试验结果证明了该观测器的有效性.     

Dependence of the flux flow viscosity coefficient on the Ginzburg-Landau parameter κ in superconducting indium films

The flux flow viscosity coefficient b ^–1 (in units of ₀ H _{c n} ^–1 c ^–2) of vacuum-deposited indium thin films with low values (1.0–2.8) is measured at temperatures between 0.5T _cand 0.98T _cin the weak magnetic field region. At each temperature, b ^–1 decreases as increases for larger than 1.7. The decrease of b ^–1 with increasing is more rapid as the temperature increases. From an analysis of the present results as well as the existing data on intermediate- and high- superconducting alloys, the relation between b ^–1 and is established over a wide range of . The dependence of b ^–1 on is qualitatively explained by taking into account the contribution of the normal electron dissipation to the viscosity coefficient in the Bardeen-Stephen model.Financial support provided by the Fonds National Suisse de la Recherche Scientifique.On leave from the Department of Electronic Engineering, Faculty of Engineering, Kyushu Industrial University, Fukuoka, Japan.     

An evolutionarily conserved family of Hsp70/Hsc70 molecular chaperone regulators

Heat Shock Protein 70 kDa (Hsp70) family molecular chaperones play critical roles in protein folding and trafficking in all eukaryotic cells. The mechanisms by which Hsp70 family chaperones are regulated, however, are only partly understood. BAG-1 binds the ATPase domains of Hsp70 and Hsc70, modulating their chaperone activity and functioning as a competitive antagonist of the co-chaperone Hip. We describe the identification of a family of BAG-1-related proteins from humans (BAG-2, BAG-3, BAG-4, BAG-5), the invertebrate Caenorhabditis elegans (BAG-1, BAG-2), and the fission yeast Schizosaccharomyces pombe (BAG-1A, BAG-1B). These proteins all contain a conserved approximately 45-amino acid region near their C termini (the BAG domain) that binds Hsc70/Hsp70, but they differ widely in their N-terminal domains. The human BAG-1, BAG-2, and BAG-3 proteins bind with high affinity (KD congruent with 1-10 nM) to the ATPase domain of Hsc70 and inhibit its chaperone activity in a Hip-repressible manner. The findings suggest opportunities for specification and diversification of Hsp70/Hsc70 chaperone functions through interactions with various BAG-family proteins.     

Biodegradation of glutaraldehyde-tanned human umbilical vein grafts

A retrospective analysis of the long-term behavior of 111 glutaraldehyde-tanned human umbilical vein (HUV) grafts implanted between September 1977 and December 1993 was conducted. A total of 81 patients, with a mean age of 68.7 years, received the grafts and were followed up for between 1 and 131 months. The 5-year primary cumulative patency rate for above-knee femoropopliteal bypass was 83.1%, whereas that of other bypasses was 60.9%. An aneurysm of the graft was defined as a physically apparent localized dilatation, with diffuse ectasia being excluded. There were 11 aneurysms found in 9 grafts, 2 of which arose at the factory-made suture lines. The accumulated incidence of aneurysms had reached 21.9% by the 6th year. One aneurysm compressed the graft and resulted in limb-threatening ischemia and another resulted in frank rupture. Moreover, reinforcement of the mesh could not prevent aneurysm development, the repair of which is mandatory due to the risk of rupture and acute thrombosis. The HUV grafts showed an acceptable patency rate in the above-knee location, but the incidence of aneurysm formation after 5 years was abnormally high. Thus, both the risks and benefits of HUV grafts must be taken into account when considering their clinical application.     

A Unified Approach to Submicron DC MOS Transistor Modeling for Low-Voltage ICs

A unified single-equation approach for the MOS transistordrain current modeling for energy-efficient submicron MOS circuitsis presented. Instead of three sets of separate equations forthe triode, saturation, and weak inversion regions, only a continuousexpression which is valid to describe the behavior of drain currentand the derivatives in all operation regions can be realizedby using a combination of hyperbola, sigmoid, and interpolationmethods. The model expression can predict accurate results forthe current, output conductance, and transconductance with continuousand smooth characteristics. The simulation results agree wellwith experimental data.     

Pose-Invariant Facial Expression Recognition Using Variable-Intensity Templates

In this paper, we propose a method for pose-invariant facial expression recognition from monocular video sequences. The advantage of our method is that, unlike existing methods, our method uses a simple model, called the variable-intensity template, for describing different facial expressions. This makes it possible to prepare a model for each person with very little time and effort. Variable-intensity templates describe how the intensities of multiple points, defined in the vicinity of facial parts, vary with different facial expressions. By using this model in the framework of a particle filter, our method is capable of estimating facial poses and expressions simultaneously. Experiments demonstrate the effectiveness of our method. A recognition rate of over 90% is achieved for all facial orientations, horizontal, vertical, and in-plane, in the range of ±40 degrees, ±20 degrees, and ±40 degrees from the frontal view, respectively. Electronic Supplementary Material  The online version of this article () contains supplementary material, which is available to authorized users.     

Motion control of electric vehicles and prospects of supercapacitors

Novel motion control techniques for electric vehicles (EVs) on the basis of the quick torque generation in these vehicles have been developed at the Hori Laboratory. Because EVs are powered by electric motors, they have three major advantages: (i) motor torque generation is quick and accurate, (ii) a motor can be attached to each wheel, and (iii) motor torque can be estimated precisely. These advantages enable us to (i) easily realize high-performance antilock braking systems and traction control systems with minor feedback control of each wheel, (ii) control chassis motion, for example, direct yaw control, and (iii) estimate road surface condition. We have developed test vehicles and confirmed the effectiveness of the proposed methods. Recently, we have manufactured small EVs that are powered only by supercapacitors. Supercapacitors have long operating life, large current density, and are environmental friendly. Furthermore, their energy level can be estimated from their terminal voltage. Because EVs powered by supercapacitors can run for more than 20 min by charging only for 30 s, recharging EVs will not be a major problem. In the future, EVs will be recharged via contactless power transfer. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.