Inversion-mode InP MISFET using a photochemical phosphorus nitride gate insulator

An inversion-mode n-channel InP MISFET is fabricated using a photochemical phosphorus nitride film as a gate insulator. An effective electron mobility of ~1700 to 2200 cm2/Vs is obtained and the drain current maintains more than 80% of its initial value after 103 s at room temperature. These values are much superior to the characteristics of InP MISFETs using thermally deposited phosphorus nitride gate insulators. These improvements are probably caused by the reduction of thermal degradation of InP substrates through the application of the photochemical CVD technique.     

New InGaAs/InP avalanche photodiode structure for the 1-1.6 µm wavelength region

Low dark current and low multiplication noise properties for an In0.53Ga0.47As/InP avalanche photodiode are described. The diode is prepared with an In0.53Ga0.47As light absorption layer and an InP avalanche multiplication region. The lowest dark current density of5.2 times 10^{-4}A/cm²is obtained at 90 percent of a breakdown voltage. Multiplication noise power is proportional to the 2.7th power of the current multiplication factor. Impact ionization coefficient by holes is larger by 2-3 times than that by electrons in     

An Optimally Controlled Respirator

An optimally controlled respirator was developed. It has three main features: 1) ventilation is controlled by the patient's metabolic rate from continuously measured C02 output, 2) physiologic dead space approximated as a linear function of tidal volume is used to estimate alveolar ventilation, and 3) respiratory rate is computed to minimize ventilatory work.     

Cyclic threshold shear strain in pore water pressure generation in clay in situ samples

The threshold level of the cyclic shear strain required for pore water pressure generation in clay samples is examined through the results of torsional hollow cylinder cyclic shearing tests according to JGS 0543-2009. The study confirms the previous results, namely, that the threshold cyclic shear strain is dependent on the effective consolidation stress and plasticity index (I_p). The average and standard deviations in the estimated threshold strain levels are 0.038?±?0.023% (I_p?<?30, σ′_c?$\leqq$?100?kN/m²), 0.047?±?0.016% (I_p?<?30, σ′_c?>?100?kN/m²), 0.079?±?0.028% (30?$\leqq$?I_p?<?5?0), and 0.143?±?0.041% (I_p?$\geqq$?50). As was found in past research, the levels of threshold strain for pore water pressure generation for clay are larger than those for clean sand. An increase in pore water pressure is only observed when the stiffness is reduced to around 80% of its initial value. This delay occurs because there is a difference between the cyclic threshold strain of the pore water pressure generation, γ_tp, and the cyclic threshold strain of the stiffness degradation, γ_td. Since the test procedure of JGS 0543-2009 is a standard scheme in the practical design process, it is expected that more data will become available in the near future which will allow for further discussions on threshold strain.     

Effects of back cooling with Peltier devices on thermoregulatory responses in a hot environment

To prevent individuals with thermoregulatory dysfunction from becoming hyperthermic in a hot environment, we propose a back‐cooling (BC) system with Peltier devices mounted on a wheelchair backrest. Here, we characterize the changes in thermoregulatory responses induced by BC in order to confirm the feasibility of the proposed system. A cooling experiment in a climate chamber at 33°C with six able‐bodied subjects demonstrated that the amount of sweating and systolic blood pressure were significantly lower in the BC trials than in the no‐cooling trials, providing preliminary evidence that BC can partially replace thermoregulatory responses and reduce the heat burden. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

S-Denitrosylase-Like Activity of Cyclic Diselenides Conjugated with Xaa-His Dipeptide: Role of Proline Spacer as a Key Activity Booster

This study developed dipeptide-conjugated 1,2-diselenan-4-amine ( 1 ), i. e., 1 -Xaa-His, as a new class of S-denitrosylase mimic. The synthesized compounds, especially 1 -Pro-His, remarkably promoted S-denitrosylation of nitrosothiols (RSNO) via a catalytic cycle involving the reversible redox reaction between the diselenide and its corresponding diselenol ([SeH,SeH]) form with coexisting reductant thiols (R′SH), during which the [SeH,SeH] form as a key reactive species reduces RSNO to the corresponding thiol (RSH). Structural analyses of 1 -Pro-His suggested that the peptide backbone of [SeH,SeH] is rigidly bent to form a γ-turn, possibly including an NH⋅⋅⋅Se hydrogen bond between the imidazole ring of His and selenol group, thus stabilizing the [SeH,SeH] form thermodynamically, and dramatically enhancing the catalytic activity. Furthermore, the synthetic compounds were found to prohibit S-nitrosylation-induced protein misfolding in the presence of RSNO, eventually implying their potential as a drug seed for misfolding diseases caused by the dysregulation of the S-denitrosylation system.     

Synthesis of Short Peptides with Perfluoroalkyl Side Chains and Evaluation of Their Cellular Uptake Efficiency

With an increasing demand for macromolecular biotherapeutics, the issue of their poor cell-penetrating abilities requires viable and relevant solutions. Herein, we report tripeptides bearing an amino acid with a perfluoroalkyl (R_F) group adjacent to the α-carbon. R_F-containing tripeptides were synthesized and evaluated for their ability to transport a conjugated hydrophilic dye (Alexa Fluor 647) into the cells. R_F-containing tripeptides with the fluorophore showed high cellular uptake efficiency and none of them were cytotoxic. Interestingly, we demonstrated that the absolute configuration of perfluoroalkylated amino acids (R_F-AAs) affects not only nanoparticle formation but also the cell permeability of the tripeptides. These novel R_F-containing tripeptides are potentially useful as short and noncationic cell-penetrating peptides (CPPs).