Performance Evaluation of Variable Bandwidth Channel Allocation Scheme in Multiple Subcarrier Multiple Access

Multiple Subcarrier Multiple Access (MSMA) enables concurrent sensor data streamings from multiple wireless and batteryless sensors using the principle of subcarrier backscatter used extensively in passive RFID. Since the interference cancellation performance of MSMA depends on the Signal to Interference plus Noise Ratio of each subcarrier, the choice of channel allocation scheme is essential. Since the channel allocation is a combinatorial problem, obtaining the true optimal allocation requires a vast amount of examinations which is impracticable in a system where we have tens of sensor RF tags. It is particularly true when we have variable distance and variable bandwidth sensor RF tags. This paper proposes a channel allocation scheme in the variable distance and variable bandwidth MSMA system based on a newly introduced performance index, total contamination power, to prioritize indecision cases. The performance of the proposal is evaluated with existing methods in terms of average communication capacity and system fairness using MATLAB Monte Carlo simulation to reveal its advantage. The accuracy of the simulation is also verified with the result obtained from the brute force method

A Case of Traumatic Cyclodialysis Followed by Ultrasound Biomicroscopy

We report a case of persistent traumatic cyclodialysis treated bygoniophotocoagulation and observed by ultrasound biomicroscopy (UBM) throughout the course.A 16 year-old male was struck in his right eye by a rocket firework. After the injury,hypotony continued for 4 months and he was referred to Hiroshima University Hospital. Atthat time, the best visual acuity in his right eye was 0.2 and the intraocular pressure was6 mmHg. Three hundred and sixty degrees of cyclodialysis, partial peripheral anteriorsynechia, hypotony maculopathy and subretinal proliferative tissue were observed.Cyclodialysis was obvious by UBM. From 4 months after the injury goniophotocoagulation wasperformed six times in 2 months. Intraocular pressure recovered 6 months after the injuryand reattachment of cyclodialysis and disappearance of the suprachoroidal space wereconfirmed by UBM. UBM was useful in observing cyclodialysis throughout the course

Cu Species Incorporated into Amorphous ZrO₂ with High Activity and Selectivity in CO₂‑to-Methanol Hydrogenation

We prepared Cu/a-ZrO₂ (a-ZrO₂: amorphous ZrO₂), Cu/m-ZrO₂ (m-ZrO₂: monoclinic ZrO₂), Cu/a-ZrO₂/KIT-6, and Cu/t-ZrO₂/KIT-6 (t-ZrO₂: tetragonal ZrO₂) by a simple impregnation method and examined the effect of the ZrO₂ phase on CO₂-to-methanol hydrogenation. We discovered a-ZrO₂-containing catalysts with high activity and selectivity in CO₂-to-methanol hydrogenation. Next, we focused on Cu species formation on the above-described catalysts. While pure CuO was observed on Cu/m-ZrO₂ and Cu/t-ZrO₂/KIT-6, copper-zirconium mixed oxide (Cu_<i>x</i>Zr_<i>y</i>O_<i>z</i>), not pure CuO, was formed on Cu/a-ZrO₂ and Cu/a-ZrO₂/KIT-6, as evidenced by X-ray absorption spectroscopy (XAS) and the powder color. After reducing a-ZrO₂-containing catalysts with H₂ at 300 °C, we observed highly dispersed Cu nanoparticles in close contact with a-ZrO₂ (or Cu_<i>x</i>Zr_<i>y</i>O_<i>z</i>). In addition, methanol vapor sorption revealed that methanol adsorbed more weakly on a-ZrO₂ than on m-ZrO₂. Therefore, the high dispersion of Cu species and weak adsorption of methanol led to high activity and selectivity in CO₂-to-methanol hydrogenation

Design of Interfacial Sites between Cu and Amorphous ZrO₂ Dedicated to CO₂‑to-Methanol Hydrogenation

We examined the formation mechanism of active sites on Cu/ZrO₂ specific toward CO₂-to-methanol hydrogenation. The active sites on Cu/<i>a</i>-ZrO₂ (<i>a</i>-: amorphous) were more suitable for CO₂-to-methanol hydrogenation than those on Cu/<i>t</i>-ZrO₂ (<i>t</i>-: tetragonal) and Cu/<i>m</i>-ZrO₂ (<i>m</i>-: monoclinic). When <i>a</i>-ZrO₂ was impregnated with a Cu­(NO₃)₂·3H₂O solution and then calcined under air, most of the Cu species entered <i>a</i>-ZrO₂, leading to the formation of a Cu–Zr mixed oxide (Cu_<i>a</i>Zr_1‑<i>a</i>O_<i>b</i>). The H₂ reduction of the thus-formed Cu_<i>a</i>Zr_1‑<i>a</i>O_<i>b</i> led to the formation of Cu nanoparticles on <i>a</i>-ZrO₂, which can be dedicated to CO₂-to-methanol hydrogenation. We concluded that the selective synthesis of Cu_<i>a</i>Zr_1‑<i>a</i>O_<i>b</i>, especially amorphous Cu_<i>a</i>Zr_1‑<i>a</i>O_<i>b</i>, is a key feature of the catalyst preparation. The preparation conditions of the amorphous Cu_<i>a</i>Zr_1‑<i>a</i>O_<i>b</i> specific toward CO₂-to-methanol hydrogenation is as follows: (i) Cu­(NO₃)₂·3H₂O/<i>a</i>-ZrO₂ is calcined at low temperature (350 °C in this study) and (ii) the Cu loading is low (6 and 8 wt % in this study). Via these preparation conditions, the characteristics of <i>a</i>-ZrO₂ for the catalysts remained unchanged during the reaction at 230 °C. The latter preparation condition is related to the solubility limit of Cu species in <i>a</i>-ZrO₂. Accordingly, we obtained the amorphous Cu_<i>a</i>Zr_1‑<i>a</i>O_<i>b</i> without forming crystalline CuO particles

Systemic hemodynamics in advanced cirrhosis: Concerns during perioperative period of liver transplantation

Advanced liver cirrhosis is usually accompanied by portal hypertension. Long-term portal hypertension results in various vascular alterations. The systemic hemodynamic state in patients with cirrhosis is termed a hyperdynamic state. This peculiar hemodynamic state is characterized by an expanded blood volume, high cardiac output, and low total peripheral resistance. Vascular alterations do not disappear even long after liver transplantation (LT), and recipients with cirrhosis exhibit a persistent systemic hyperdynamic state even after LT. Stability of optimal systemic hemodynamics is indispensable for adequate portal venous flow (PVF) and successful LT, and reliable parameters for optimal systemic hemodynamics and adequate PVF are required. Even a subtle disorder in systemic hemodynamics is precisely indicated by the balance between cardiac output and blood volume. The indocyanine green (ICG) kinetics reflect the patient’s functional hepatocytes and effective PVF, and PVF is a major determinant of the ICG elimination constant (kICG) in the well-preserved allograft. The kICG value is useful to set the optimal PVF during living-donor LT and to evaluate adequate PVF after LT. Perioperative management has a large influence on the postoperative course and outcome; therefore, key points and unexpected pitfalls for intensive management are herein summarized. Transplant physicians should fully understand the peculiar systemic hemodynamic behavior in LT recipients with cirrhosis and recognize the critical importance of PVF after LT