High-performance liquid chromatography (HPLC) is the most common analytical method practiced in various fields and used for analysis of almost all drug compounds in the pharmaceutical industries. ...During drug development, an evaluation of potential drug interaction with cytochrome P450 (CYP) is essential. A "cocktail" approach is often used in drug development to evaluate the effect of a drug candidate on multiple CYP enzymes in a single experiment. So far, simultaneous analysis of multiple CYP substrates, which have greatly different structure and physicochemical properties, has required organic solvents and mobile phase gradient methods. However, despite the recent emphasis on environmental protection, analytical methods that use only aqueous solvents without the use of organic solvents for separation have not been studied well. This study sought to develop the simultaneous analysis of multiple CYP substrates by using poly(N-isopropylacrylamide) (PNIPAAm)-based temperature-responsive chromatography with only aqueous solvents and isocratic methods. Good separation of multiple CYP substrates was achieved without using organic solvents and any gradient methods by temperature-responsive chromatography utilizing a P(NIPAAm-co-n-butyl methacrylate (BMA))- and P(NIPAAm-co-N-acryloyl L-tryptophan methyl ester (L-Trp-OMe))-grafted silica column. Overall, PNIPAAm-based temperature-responsive chromatography represents a remarkably simple, versatile, and environmentally friendly bioanalytical method for CYP substrates and their metabolites.
The direct optimization of ship hull designs using deep learning algorithms is increasingly expected, as it proposes optimization directions for designers almost instantaneously, without relying on ...complex, time-consuming, and expensive hydrodynamic simulations. In this study, we proposed a GAN-based 3D ship hull design optimization method. We eliminated the dependence on hydrodynamic simulations by training a separate model to predict ship performance indicators. Instead of a standard discriminator, we applied a relativistic average discriminator to obtain better feedback regarding the anomalous designs. We add two new loss functions for the generator: one restricts design variability, and the other sets improvement targets using feedback from the performance estimation model. In addition, we propose a new training strategy to improve learning effectiveness and avoid instability during training. The experimental results show that our model can optimize the form factor by 5.251% while limiting the deterioration of other indicators and the variability of the ship hull design.
Kusatsu–Shirane Volcano is an active Quaternary andesitic-to-dacitic volcano located in the Central Japan Arc. We conducted a detailed petrological investigation of orthopyroxene (opx)–magnetite (mt) ...symplectites associated with olivine in the Sessho lava, an andesitic lava flow from Kusatsu–Shirane. We concluded that the symplectites are pseudomorphs after olivine and were formed through the breakdown of olivine in a mafic magma as a result of oxidation during mixing with a felsic magma. Various olivines and opx–mt symplectites that show different stages of the progressive breakdown reaction of olivine coexist in a single lava flow. We suggest that basaltic recharge into the magma reservoir beneath Kusatsu–Shirane occurred repeatedly, leading to a hybrid andesite magma with different types of olivine and symplectite being erupted at Kusatsu–Shirane Volcano.
Position‐controlled vapor‐liquid‐solid (VLS) growth of nanowires (NWs) is investigated using GaAs substrates with SiN‐patterned masks and Au catalysts for the realization of axial GaAsSb/InAs ...heterostructures. Rod‐like InAs NWs are obtained by the introduction of a small amount of HCl gas. The InAs NW diameter depends on the Au catalyst size and pitch of NWs, which can be explained by the VLS growth accompanied by lateral growth. A peculiar change in NW shapes for additive HCl gas is also revealed. Moreover, the formation of axial GaAsSb/InAs heterostructure NWs, by controlling the growth temperature of GaAsSb segments is demonstrated. These results indicate that this growth method is promising for the development of NWs suitable for vertical nano‐scale devices with Sb‐containing heterostructures.
Position‐controlled VLS growth of nanowires (NWs) is investigated for GaAsSb/InAs system. Growth properties of InAs NWs are defined by the VLS mechanism and patterned‐mask effect, and a peculiar change in InAs NW shapes for additive HCl gas is revealed. The formation of axial GaAsSb/InAs heterostructure NWs is demonstrated.
This work shows a broadband, high-efficiency power amplifier (PA) monolithic microwave integrated circuit (MMIC) that uses InP-based metal-oxide-semiconductor (MOS) high-electron-mobility transistors ...(HEMTs) with an extended drain-side access region and broadband conjugate matching topology. Advanced device technologies, namely, double-side-doped structures, MOS gate structures, and asymmetric gate recess, were adopted, and the length of the drain-side access region was optimized to simultaneously obtain high power and efficiency. A common-source PA MMIC based on InP-based MOS-HEMTs was fabricated, and an interstage circuit was designed to maximize the S21 per unit stage in the broadband, resulting in a record-high power-added efficiency and wide bandwidth.
This paper investigated the back‐barrier (BB) effect for gallium nitride (GaN)‐based high‐electron‐mobility transistors with an Fe‐doped buffer and Fe‐buffer + Indium gallium nitride (InGaN)‐BB ...structure. The authors found that the Fe‐doped buffer + InGaN‐BB structure was effective in reducing the off‐state leakage current compared to the Fe‐doped buffer. Secondary‐ion‐mass spectrometry measurements revealed that the segregated Fe existed with peaks at ∼2 × 1017 cm−3 around the InGaN‐BB layer. The authors believe that the negative charges which are generated by Fe effectively increased the BB effect as they exist just underneath the 2‐dimensional‐electron‐gas channel and successfully achieved a high output power operation of 4.6 W/mm at 94 GHz.
The high output power density of 4.6 W/mm at 94 GHz was achieved for GaN‐HEMT using Fe‐buffer + InGaN BB structure.
A high-efficiency uniform/selective heating microwave oven was developed. Because the power amplifier requires high-efficiency characteristics to function as a microwave source, a free-standing ...Gallium Nitride (GaN) substrate was applied in this study. By applying a harmonic tuning circuit, an output power of 71 W and PAE of 73% were achieved in pulsed operation, and an output power of 63 W and PAE of 69% were achieved in CW operation. Moreover, we fabricated a prototype PA module that consists of an oscillator, a driver amplifier, PA, and other RF circuits. The output power was controlled by pulse width modulation to maintain high efficiency regardless of output power. We evaluated the arrangement of antenna polarizations to isolate each antenna. By suppressing the interference of output from adjacent antennas, it is possible to irradiate the object on the top surface of the antenna, thereby demonstrating heating characteristics with small temperature unevenness. The prototype microwave oven successfully demonstrated uniform/selective heating.
In this study, we investigated the heat dissipation characteristics of gallium nitride (GaN) high-electron mobility transistors (HEMTs) fabricated on a freestanding GaN substrate (GaN-on-GaN HEMTs) ...by simulation. Although the GaN substrate has a lower thermal conductivity than the conventional silicon carbide (SiC) substrate, it was demonstrated that the GaN-on-GaN HEMT has a thermal resistance comparable to the conventional GaN-on-SiC HEMT in a simulated structure composed of a 100-<inline-formula> <tex-math notation="LaTeX">\mu \text{m} </tex-math></inline-formula>-thick substrate and a 2-<inline-formula> <tex-math notation="LaTeX">\mu \text{m} </tex-math></inline-formula>-thick GaN epitaxial layer. This is because GaN-on-GaN has a higher thermal conductivity of the GaN epitaxial layer and a lower thermal boundary resistance than GaN-on-SiC. Next, the thermal design of a 400-W/eight-channel selective heating microwave oven, which consists of eight pairs of patch antennas and power amplifier (PA) modules, involving a 50-W-class GaN-on-GaN HEMT PA, a driving amplifier, an oscillator, and several circuits, was carried out. The fan and fin specifications and enclosure configuration have been optimized to keep the temperature of the metal base on which the PA modules are mounted below 40 °C during full operation. Excellent agreement between the oven thermal simulation and the prototype thermocouple measurements was confirmed for the temperature difference between the metal base and the ambient. Finally, device dimensions for reliable operation were determined by simulating the channel temperature of the GaN-on-GaN HEMT PA during microwave heating. To keep the maximum channel temperature below 200 °C, the simulated device layout with a unit gate width (<inline-formula> <tex-math notation="LaTeX">W_{\mathrm {gu}} </tex-math></inline-formula>) of 100-<inline-formula> <tex-math notation="LaTeX">300~\mu \text{m} </tex-math></inline-formula> and a gate-to-gate spacing (<inline-formula> <tex-math notation="LaTeX">L_{\mathrm {gg}} </tex-math></inline-formula>) of 30-<inline-formula> <tex-math notation="LaTeX">70~\mu \text{m} </tex-math></inline-formula> was acceptable at a drain efficiency (<inline-formula> <tex-math notation="LaTeX">\eta _{\mathrm {D}} </tex-math></inline-formula>) of 75%. However, appropriate <inline-formula> <tex-math notation="LaTeX">W_{\mathrm {gu}} </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">L_{\mathrm {gg}} </tex-math></inline-formula> were found to be required with a <inline-formula> <tex-math notation="LaTeX">\eta _{\mathrm {D}} </tex-math></inline-formula> of 65%.
In this study, a p-GaAs0.4Sb0.6/n-InAs nanowire backward diode (NW BWD) with a large sensitivity of 706 kV/W, exceeding that of Schottky barrier diodes (SBDs), was developed for low-power microwave ...rectification at zero bias. The interband tunneling of the NW BWDs under zero-bias condition displayed a large nonlinear characteristic of typical BWDs, which is effective for realizing power detection with high sensitivity. The fabricated NW BWDs indicated linear detected voltages (Vdet) when a microwave input power (Pin) of ∼1 µW was applied at 2.4 GHz. From the Vdet, Pin, and return loss obtained from the S-parameter measurements, an impedance-matched voltage sensitivity of 706 kV/W was calculated for the NW BWD at zero bias. The obtained sensitivity value was higher than that of a well-designed SBD, which was ∼62 kV/W at 2.4 GHz. According to the extracted device parameters, it was found that to improve the sensitivity of the NW-BWD, not only the junction capacitance of the diode but also the parasitic pad capacitance needs to be reduced. The high sensitivity is attributed to the high curvature coefficient of −26.7 V−1 and the small junction capacitance of the NW structure of the BWD.
Meteorological-tsunami-like (or meteotsunami-like) periodic oscillation was muographically detected with the Tokyo-Bay Seafloor Hyper-Kilometric Submarine Deep Detector (TS-HKMSDD) deployed in the ...underwater highway called the Trans-Tokyo Bay Expressway or Tokyo Bay Aqua-Line (TBAL). It was detected right after the arrival of the 2021 Typhoon-16 that passed through the region 400 km south of the bay. The measured oscillation period and decay time were respectively 3 h and 10 h. These measurements were found to be consistent with previous tide gauge measurements. Meteotsunamis are known to take place in bays and lakes, and the temporal and spatial characteristics of meteotsunamis are similar to seismic tsunamis. However, their generation and propagation mechanisms are not well understood. The current result indicates that a combination of muography and trans-bay or trans-lake underwater tunnels will offer an additional tool to measure meteotsunamis at locations where tide gauges are unavailable.
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