The most common mechanism 1 for generating ultrasound in air is via a piezoelectric transducer, whereby an electrical signal is converted directly into a mechanical vibration. But the acoustic pressure so generated is usually limited to less than 10 Pa, the frequency bandwidth of most piezoelectric ceramics is narrow, and it is difficult to assemble such transducers into a fine-scale phase array with no crosstalk 2,3 . An alternative strategy using micromachined electrostatic diaphragms is showing some promise 4,5 , but the high voltages required and the mechanical weakness of the diaphragms may prove problematic for applications. Here we show that simple heat conduction from porous silicon to air results in high-intensity ultrasound without the need for any mechanical vibrational system. Our non-optimized device generates an acoustic pressure of 0.1 Pa at a power consumption of 1 W cm −2 , and exhibits a flat frequency response up to at least 100 kHz. We expect that substantial improvements in efficiency should be possible. Moreover, as this material lends itself to integration with conventional electronic circuitry, it should be relatively straightforward to develop finely structured phase arrays of these devices, which would give control over the wavefront of the acoustic emissions.

Uremic pruritus is a very common and frustrating condition for both patients and clinicians because no treatment has been demonstrated to be effective in relieving the itch. In this report, nalfurafine, a new -opioid receptor agonist, was used to treat uremic pruritus in patients who were undergoing routine hemodialysis. Two multicenter, randomized, double-blind, placebocontrolled studies enrolled 144 patients with uremic pruritus to postdialysis intravenous treatment with either nalfurafine or placebo for 2 to 4 wk. A meta-analysis approach was used to assess the efficacy of nalfurafine. Statistically significant reductions in worst itching (P ‫؍‬ 0.0212), itching intensity (P ‫؍‬ 0.0410), and sleep disturbances (P ‫؍‬ 0.0003) were noted in the nalfurafine group as compared with placebo. Improvements in itching (P ‫؍‬ 0.0025) and excoriations (P ‫؍‬ 0.0060) were noted for the nalfurafine-treated patients. Nalfurafine showed similar types and incidences of drug-related adverse events as did placebo. Nalfurafine was shown to be an effective and safe compound for use in this severely ill patient population. U remic pruritus has a major impact on the quality of life in patients who already have a compromised lifestyle (1-5). It is, of itself, not a life-threatening condition; however, it is known to contribute to an increase in morbidity (6) and mortality (7) of uremic patients. The only current definitive treatment for uremic pruritus is successful renal transplantation (8). Increasing the dialysis dose as well as implementing other therapeutic measures to lessen the symptoms, some as extraordinary as acupressure, (9) have provided only limited effectiveness in dialysis patients.Stimulation of the -opioid receptor in the brain and/or peripheral nerve endings by its agonists, such as morphine, can result in itching (10 -12). -Opioid receptor antagonists can inhibit itching induced by substance P (13). -Opioid stimulation inhibits -receptor effects both centrally and peripherally (11). Nalfurafine, a new -opioid receptor agonist, was effective in reducing the scratching behavior induced by an injection of substance P in the mouse model (13,14). From these findings, it was hypothesized that uremic pruritus could be triggered and sustained by the release of substance P (15). This led to the studies in the treatment of uremic pruritus using nalfurafine. Materials and Methods Study Design and TreatmentsTwo multicenter, randomized, double-blind, placebo-controlled clinical studies were performed with the common objective of assessing the efficacy and the safety of nalfurafine, as compared with placebo, in the treatment of uremic pruritus. The inclusion and exclusion criteria and the evaluations, methods of evaluations, and times of evaluations were the same in both studies.Patients were males and females who were at least 18 yr of age and undergoing routine hemodialysis secondary to ESRD and had severe, uncontrolled pruritus caused only by ESRD. Female patients were not of childbearing potential or were using an acceptab...

All‐solid‐state batteries (ASSBs) with inorganic solid electrolytes (SEs) have attracted significant interest as next‐generation energy storage. Halides such as Li3YCl6 are promising candidates for SE because they combine high oxidation stability and deformability. However, the ionic conductivities of halide SEs are not as high as those of other SEs, especially sulfides. Here, we discover new lithium‐metal‐oxy‐halide materials, LiMOCl4 (M=Nb, Ta). They exhibit extremely high ionic conductivities of 10.4 mS cm−1 for M=Nb and 12.4 mS cm−1 for M=Ta, respectively, even in cold‐pressed powder forms at room temperature, which are comparable to or surpass those of organic liquid electrolytes used in lithium‐ion batteries. Bulk‐type ASSB cells using the oxyhalides as the cathode SE demonstrate an outstanding rate capability with a capacity retention of 80 % at 5 C/0.1 C. We believe that the proposed oxyhalides are promising SE candidates for the practical applications of ASSBs.

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The ternary zinc nitrides CaZn 2 N 2 and SrZn 2 N 2 are promising materials for solar energy conversion because their direct band gaps are tunable to optimal values, and they contain only earth-abundant elements. We report first-principles calculations with a focus on defect chemistry and propose a method of synthesis for SrZn 2 N 2 . Our calculations reveal that although the N vacancy has a relatively low formation energy among the native defects in SrZn 2 N 2 and shows deep levels within the band gap, its concentration can be sufficiently reduced by controlled crystal growth and extrinsic doping. The SrZn 2 N 2 powder was synthesized by NH 3 nitridation of the SrZn 2 alloy at 600 °C and atmospheric pressure. We experimentally determined the direct band gap of SrZn 2 N 2 to be 1.6 eV, consistent with our theoretical prediction.

It is demonstrated that there are distinct off and on states in the current–voltage characteristics of porous silicon (PS) diodes, and that the visible electroluminescence (EL) is observed in the on state. The PS diodes are composed of semitransparent thin Au films, rapid thermal oxidization (RTO)-treated PS layers (∼0.5 μm thick), p-type Si substrates, and ohmic back contacts. After the PS layers were prepared by anodizing Si wafers in an ethanoic HF solution, the samples were treated by RTO process. The bistable states of this PS diode can be simply and reversibly controlled by the external bias voltage. Based on the behavior of the EL and capacitance–voltage characteristics, the model of memory effect is presented, in which field-induced carrier injection and ejection into and from silicon nanocrystallites strongly affects the carrier transport.

A segmented mirror system is essential to realize extremely large telescopes. In this paper, we discuss the conceptual design for the control system of the segmented primary mirror in the SEIMEI telescope employing 18 segments, 72 sensors, and 54 actuators. Two types of control algorithms, Centralized Control System (CCS) and Distributed Control System (DCS), are presented. CCS drives all the segments by integrated information of all sensors and DCS drives each segment by individual information of local sensors, and they are expected to play complementary roles. The effectiveness of CCS and DCS are demonstrated by numerical simulations.