Synthesis and ion transport properties of RE3GaO6 (RE = rare earth) oxide ion conductors

First-principles calculations were conducted, which proposed that members of the RE₃GaO₆ (RE = rare earth) system were oxide ion conductors. This study experimentally verified oxide ion conduction in Dy₃GaO₆, Er₃GaO₆, and Nd₃GaO₆. The sintered bodies were synthesized by a solid-state reaction method, and their properties were characterized. The samples with dopants were observed to be mixed electron and oxide ion conductors. Dy_2.85Ca_0.15GaO_6-δ exhibited oxide ion conductivities of 2.1 × 10^?4 S/cm at 973 K, with an oxide ion transport number of 21 % under O₂ gas flow. Additionally, the Rietveld refinement suggested that oxide ion migration might occur via the oxide ion vacancy between the O2 sites. Overall, the oxide ion conductivities of RE₃GaO₆ increased in the following order: Nd > Dy > Er, which was in good agreement with that predicted by using the first-principles calculations. The discrepancy between the experimentally measured and predicted conductivities was caused by the solid-solution limit at the RE site for the dopants.     

Controllable Magnetic Proximity Effect and Charge Transfer in 2D Semiconductor and Double-Layered Perovskite Manganese Oxide van der Waals Heterostructure

Optically generated excitonic states (excitons and trions) in transition metal dichalcogenides are highly sensitive to the electronic and magnetic properties of the materials underneath. Modulation and control of the excitonic states in a novel van der Waals (vdW) heterostructure of monolayer MoSe₂ on double-layered perovskite Mn oxide ((La_0.8Nd_0.2)_1.2Sr_1.8Mn₂O₇) is demonstrated, wherein the Mn oxide transforms from a paramagnetic insulator to a ferromagnetic metal. A discontinuous change in the exciton photoluminescence intensity via dielectric screening is observed. Further, a relatively high trion intensity is discovered due to the charge transfer from metallic Mn oxide under the Curie temperature. Moreover, the vdW heterostructures with an ultrathin h-BN spacer layer demonstrate enhanced valley splitting and polarization of excitonic states due to the proximity effect of the ferromagnetic spins of Mn oxide. The controllable h-BN thickness in vdW heterostructures reveals a several-nanometer-long scale of charge transfer as well as a magnetic proximity effect. The vdW heterostructure allows modulation and control of the excitonic states via dielectric screening, charge carriers, and magnetic spins.     

Analysis of the unique gait mechanism of locusts focusing on the difference in leg length

The various types of gaits shown by insects are very interesting, and many studies have been conducted to investigate the mechanism of these gaits. In nature, there are many insects with apparent differences in the length of each leg, and it seems that the difference in leg length may affect the resultant gait of insects. However, there has not been much discussion about the influence of these differences in leg length on the gait. In this research, in order to investigate the influence of the difference in leg length on gait, we focus on locusts, whose hind legs are considerably longer than the other legs and shows a unique gait not seen in other insects. First, we measure the kinematics of gait of some insects, including locusts, and analyze the unique gait specific to locusts. Next, we reproduce this unique gait via numerical dynamical simulation. By conducting some simulations while changing the length of the legs, we investigate the mechanism of the unique gait of locusts and the influence of difference in leg length on walking. As a result, it is confirmed that the unique gait of locusts can be reproduced with a combination of long hind legs (compared to the front and middle legs) and the adjustment of the stroke and period of the hind leg based on horizontal ground reaction force.     

Functional Domain Order of an Anti-EGFR × Anti-CD16 Bispecific Diabody Involving NK Cell Activation

Bispecific antibodies (bsAbs) have emerged as promising therapeutics. A bispecific diabody (bsDb) is a small bsAb consisting of two distinct chimeric single-chain components, with two possible arrangements of the domains. We previously reported the effect of domain order on the function of a humanized bsDb targeting the epidermal growth factor receptor (EGFR) on cancer cells, and CD3 on T cells. Notably, the co-localization of a T-cell receptor (TCR) with CD3 is bulky, potentially affecting the cross-linking ability of bsDbs, due to steric hindrance. Here, we constructed and evaluated humanized bsDbs, with different domain orders, targeting EGFR and CD16 on natural killer (NK) cells (hEx16-Dbs). We predicted minimal effects due to steric hindrance, as CD16 lacks accessory molecules. Interestingly, one domain arrangement displayed superior cytotoxicity in growth inhibition assays, despite similar cross-linking abilities for both domain orders tested. In hEx16-Dbs specifically, domain order might affect the agonistic activity of the anti-CD16 portion, which was supported by a cytokine production test, and likely contributed to the superiority of one of the hEx16-Dbs. Our results indicate that both the target antigen and mode of action of an antibody must be considered in the construction of highly functional bsAbs.     

Non‐isothermal crystallization behavior of stereo diblock polylactides with relatively short poly(d‐lactide) segments from the melt

Stereo diblock polylactides (SDB‐PLAs) composed of relatively short poly(d ‐lactide) (PDLA) segments and relatively long poly(l ‐lactide) (PLLA) segments were synthesized to have a wide number‐average molecular weight (M_n) range of 2.5 × 10⁴–2.0 × 10⁵ g mol^?1 and d ‐lactyl unit content of 0.9–38.6%. The effects of incorporated short PDLA segments (M_n = 2.0 × 10³–7.7 × 10³ g mol^?1) on crystallization behavior of the SDB‐PLAs were first investigated during heating after complete melting and quenching or during slow cooling after complete melting. Stereocomplex (SC) crystallites can be formed at d ‐lactyl unit content as low as 4.3 and 5.8% for heating and slow cooling, respectively, and for M_n of PDLA segments as low as 2.0 × 10³ and 3.5 × 10³ g mol^?1, respectively. With decreasing M_n and increasing d ‐lactyl unit content, the cold crystallization temperature during heating decreased and the crystallization temperature during slow cooling increased. With increasing d ‐lactyl unit content, the melting enthalpy (ΔH_m) of SC crystallites during heating and the crystallinity (X_c) of SC crystallites after slow cooling increased, whereas ΔH_m of PLLA homo‐crystallites during heating and X_c of PLLA homo‐crystallites after slow cooling decreased. The total ΔH_m of SC crystallites and PLLA homo‐crystallites during heating and the total X_c after slow cooling became a minimum at d ‐lactyl unit content of 10–15% and gave a maximum at d ‐lactyl unit content of 0%. Despite the accelerated crystallization of some of SDB‐PLAs, the low values of total ΔH_m and X_c at d ‐lactyl unit content of 10–15% are attributable to the formation of two crystalline species of SC crystallites and PLLA homo‐crystallites.     

Estimation of long-term dietary exposure to acrylamide of the Japanese people

Acrylamide is a probable human carcinogen and known human neurotoxin. This study estimated hypothetical long-term dietary exposure to acrylamide of the Japanese people using probabilistic and deterministic approaches by combining the concentration of acrylamide in foods with the amount and frequency of food consumption in the population. Data included acrylamide concentrations in more than 2400 individual food samples from a national survey and the literature from 2004 to 2013. Food consumption amounts were derived from the data of 24,293 Japanese citizens aged 1 year and older in the 2012 National Health and Nutrition Survey. Median lifetime average dietary exposure to acrylamide was estimated as 147–154 ng/kg body weight (bw)/day (95th percentile, 226–261 ng/kg bw/day). The deterministic estimate of lifetime exposure was 158 ng/kg bw/day and ranged from 119 ng/kg bw/day for the period of life after 60 years old to 409 ng/kg bw/day for the period between 1 and 6 years old. This study found that vegetables cooked at a high temperature, coffee and cooked potato were the major food groups contributing to long-term dietary acrylamide exposure of the Japanese people.     

An Analysis of Interference Mitigation Capability of Low Duty-Cycle UWB Communications in the Presence of Wideband OFDM System

Low duty-cycle (LDC) algorithm is interference mitigation technique, which can reduce the average interference to the existing radio systems by lowering pulse repetition interval or pulse occupation time. In this paper, the coexistence environment between low data rate ultra wideband (UWB) communication system such as wireless sensor network and the existing wideband system using orthogonal frequency division multiplexing (OFDM) such as 4th generation mobile cellular system (4G), worldwide interoperability for microwave access (WiMAX), and field pickup unit (FPU) is considered. In order to analyze the interference mitigation capability of LDC algorithm with impulse based UWB (LDC-UWB) system, the frame error rate (FER) of wideband OFDM system is examined for two types of LDC-UWB system: the signal with random polarity such as binary pole signals and without random polarity such as mono pole signals. We present that LDC algorithm is an efficient interference mitigation technique for low data rate UWB communication via computer simulations regardless of definitions of transmitted energy of UWB communication system, and also that the signal with random polarity is suitable for LDC-UWB system to mitigate interference to the other radio systems. We further investigate the adequate duty-cycle of LDC-UWB system for each definition of transmitted power of UWB communication.     

Low-Frequency Spectra of Amino Acids and Short-Chain Peptides Studied by Terahertz Time-Domain Spectroscopy

The low-frequency spectra of the amino acids l-alanine and glycine and their peptides were studied using terahertz (THz) time-domain spectroscopy (TDS) at room temperature. In a previous work (Yamamoto et al., Biophys. J. 89, L22–L24 (2005)), the low-frequency spectra of amino acids (glycine and l-alanine) and their polypeptides (polyglycine and poly- l-alanine) were studied by THz-TDS, and it was found that there is a clear difference in low-frequency dynamics between the amino acids and the polypeptides. In the present study, amino acids and short peptides were chosen in order to investigate the effect of polymerization on low-frequency spectra. We focus on two physical quantities to represent the spectral features: (1) the intensity of the reduced absorption cross section (RACS), which we define from the absorption coefficient and refractive index, and (2) the exponent in the power law behavior of the RACS. We found that the two physical quantities show different dependences on peptide chain length, suggesting that the two physical quantities reflect different dynamics and interactions. The change in RACS intensity may be due to intermolecular or intrachain motion. The validity of the assumption of constant IR activity in the investigated frequency region is critical to understanding the origin of the variation in the exponent with chain length.     

Novel Calibration System with Sparse Wires for CMB Polarization Receivers

A curl competent (also known as B-modes) in the cosmic microwave background (CMB) polarization is a smoking gun signature of the inflationary universe. To achieve better sensitivity to this faint signal, CMB polarization experiments aim to maximize the number of detector elements, resulting in a large focal plane receiver. Detector calibration of the polarization response becomes essential. It is extremely useful to be able to calibrate “simultaneously” all detectors on the large focal plane. We developed a novel calibration system that rotates a large “sparse” grid of metal wires, in front of and fully covering the field of view of the focal plane receiver. Polarized radiation is created via the reflection of ambient temperature photons from the wire surface. Since the detector has a finite beam size, the observed signal is convolved with the beam property. The intensity of the of the calibrator is reasonable (a few Kelvin or less) compared to sky temperature for typical observing conditions (～10?K). The system played a successful role for receiver calibration of QUIET, a CMB polarization experiment located in the Atacama desert in Chile. The successful performance revealed that this system is applicable to other experiments based on different technologies, e.g. TES bolometers.     

Graphene growth on a Pt(111) substrate by surface segregation and precipitation

We report on the fabrication of a sizable graphene sheet on a carbon-doped Pt(111) substrate through surface segregation and precipitation. Scanning Auger electron spectroscopy (AES) reveals that the graphene covered more than 98% of the substrate surface. Our graphene consists of single-layer graphene across the substrate with fractions of several micrometer wide bi- and tri-layer graphene islands. We also show that the number of graphene layers can be precisely determined by analyzing AES data. While Raman spectroscopy is usually used to study graphene on SiO?, we show that AES is a powerful tool to characterize graphene grown on metal substrates.