Predicting the need for hospitalisation of patients with coronavirus disease 2019 (COVID-19) is important for preventing healthcare disruptions. This observational study aimed to use the COVID-19 Registry Japan (COVIREGI-JP) to develop a simple scoring system to predict respiratory failure due to COVID-19 using only underlying diseases and symptoms. A total of 6873 patients with COVID-19 admitted to Japanese medical institutions between 1 June 2020 and 2 December 2020 were included and divided into derivation and validation cohorts according to the date of admission. We used multivariable logistic regression analysis to create a simple risk score model, with respiratory failure as the outcome for young (18–39 years), middle-aged (40–64 years) and older (≥65 years) groups, using sex, age, body mass index, medical history and symptoms. The models selected for each age group were quite different. Areas under the receiver operating characteristic curves for the simple risk score model were 0.87, 0.79 and 0.80 for young, middle-aged and elderly derivation cohorts, and 0.81, 0.80 and 0.67 in the validation cohorts. Calibration of the model was good. The simple scoring system may be useful in the appropriate allocation of medical resources during the COVID-19 pandemic.

The Hodrick–Prescott (HP) filter has been a popular method of trend extraction from economic time series. However, it is impractical without modification if some observations are not available. This paper improves the HP filter so that it can be applied in such situations. More precisely, this paper introduces two alternative generalized HP filters that are applicable for this purpose. We provide their properties and a way of specifying those smoothing parameters that are required for their application. In addition, we numerically examine their performance. Finally, based on our analysis, we recommend one of them for applied studies.

In recent decades, in the research community of macroeconometric time series analysis, we have observed growing interest in the smoothing method known as the Hodrick–Prescott (HP) filter. This article examines the properties of an alternative smoothing method that looks like the HP filter, but is much less well known. We show that this is actually more like the exponential smoothing filter than the HP filter although it is obtainable through a slight modification of the HP filter. In addition, we also show that it is also like the low-frequency projection of Müller and Watson (2018, Econometrica 86, 775–804). We point out that these results derive from the fact that all three similar smoothing methods can be regarded as a type of graph spectral filter whose graph Fourier transform is discrete cosine transform. We then theoretically reveal the relationship between the similar smoothing methods and provide a way of specifying the smoothing parameter that is necessary for its application. An empirical examination illustrates the results.

Changes in crystal structure and ferroelectric properties are investigated for (100)/(001)-oriented epitaxial PbTiO3 thin films grown on CaF2 substrates by metal organic chemical vapor deposition. In this work, PbTiO3 films, with thickness ranging from 60 to 2000 nm, presented volume fraction of (001)-oriented c-domain higher than 90%. Hence, the residual strain is smaller compared to films deposited on widely investigated SrTiO3 substrates. Additionally, more than 60 μC/cm2 remnant polarization is obtained for all film thickness ranges, and the estimated spontaneous polarization taking into account c-domain volume fraction is about 80 μC/cm2 regardless of film thickness, in good agreement with reported values for the single crystal.

Epitaxial rhombohedral Pb(Zr0.65Ti0.35)O3films with (100) and (110)/(10-1) and (111)/(11-1) orientations were grown on various kinds of singlecrystal substrates having different thermal expansion coefficient. Volume fractions of (110) and (111) orientations in respective (110)/(10-1) and (111)/(11-1)-oriented films were almost linearly increased with increasing thermal strain, ε thermal, applied to the films that wasgenerated under the cooling process after the deposition from the growth temperature to the Curie temperature.Observed saturationpolarization (P sat)was changed linearly with the volume fractions of (110) and (111) orientations, in the same manner asthe volume fractions of (001) and (101) orientations in (001)/(100) and (101)/(110) oriented tetragonal Pb(Zr,Ti)O3 filmsreported previously. These results showed that the volume fraction of the non-180o domains Pb(Zr,Ti)O3films of both tetragonal and rhombohedral symmetriescan be manipulated by ε thermal, which brings possibly to control the P sat value.

The growth mechanism of large-size domains in PbTiO3/SrTiO3 heteroepitaxial thin films was examined using annular bright field (ABF) – scanning transmission electron microscopy and geometric phase analysis (GPA). {101} domain walls surrounded 90° domains. The large 90° domain grows by the coalescence of the nano-size domains of less than 5 nm width. A strain map obtained from the GPA of ABF-STEM image showed that 90° domains interacted elastically and attractively with edge dislocations at PbTiO3/SrTiO3 interface through simple shear strain.

We report the photochromism (PC) in Eu3+ doped Sr2SnO4. The Sr2SnO4:Eu3+ is sensitive to UV light (λ < 350 nm) and turns to purple color. When visible light (λ= 400-700 nm) is irradiated, the colored Sr2SnO4:Eu3+ is bleached. From the results of absorption spectrum, Sr vacancies in the host lattice and charge transfer transition between Eu3+-O2- is responsible for PC process of Sr2SnO4:Eu3+.

We report mechanoluminescence (ML) in Sm3+-doped Sr3Sn2O7 phosphors with perovskite-related structure. The ML from Sr3Sn2O7:Sm3+, emitted strong reddish-orange light upon compression, is clearly observable by naked eyes. Based on the comparison between ML spectrum and photoluminescence spectrum, the ML emission was identified to be due to electron transition from an excited state 4G5/2 to the ground state 6HJ (J = 5/2, 7/2, 9/2) in Sm3+ ions. Although the ML emission was gradually decayed as compressive load was applied repeatedly, it recovered completely upon irradiation with UV light (254 nm). This behavior indicating that ML of Sr3Sn2O7:Sm3+ is intimately related to the charge traps. The charge transfer state (CTS) band in the PL excitation spectra was observed for Sr3Sn2O7:Sm3+, indicating that the efficient energy transfer from the host to the Sm3+ ions. The formation of CTS and the charge traps may be responsible for this ML performance.

Raman scattering spectra and ferroelectric properties of epitaxial tetragonal Pb(Zr, Ti)O3 were investigated for polar axis-oriented thin films with various Zr/(Zr + Ti) ratios and by changing the ratios from 0 to 0.50 at different measurement temperatures. The chosen films in the thickness range of 1–2 μm present the advantage of showing small residual strain. The E (TO) modes were successfully isolated using cross-polarization configurations, while A1 (TO) and B1 modes were activated using parallel polarization configurations. Systematic changes in Raman peak positions were observed with changes in the Zr/(Zr + Ti) ratios at different measurement temperatures. It was found in both cases that the tetragonal distortion (c/a-1) and the value of square of spontaneous polarization (Ps2) linearly increased with increasing ω2[A1(1TO)], where a and c are the lattice parameters of a and c-axes. This indicates that monitoring A1(1TO) mode is efficient as a characterization method of ferroelectricity. It can also be used as a novel nondestructive process check or reliability assessment technique during fabrication of microelectromechanical systems (MEMS) using piezoelectric materials.

Perfectly (111)-oriented rhombohedral Pb(Zr, Ti)O3 [PZT] films were successfully grown on (111) CaF2 substrates. These films have the polar-axis perpendicular to the substrate surface without non-180o domains. Well saturated polarization (P) –electric field (E) hysteresis loops were observed at various frequencies and temperatures. Temperature dependence of the saturation polarization (P sat.) was in good agreement with the estimated one by Haun et al. using phenomenological approach but did not strongly depend on the measured frequencies. On the other hand, the coercive field (Ec ) increased with decreasing temperature and with increasing the measurement frequency.

We have developed a new class of proton-conducting organic–inorganic hybrid silicophosphite membranes, produced by ethanol condensation of organically modified alkoxysilanes and anhydrous vinylphosphonic acid under solventless, catalyst-free, low-temperature, one-pot conditions. The membranes synthesized in this study are crack-free, large, and flexible, and they exhibit good thermal stability up to intermediate temperatures (~218 °C). Structural analyses using 29Si and 31P nuclear magnetic resonance spectroscopy and infrared measurements revealed that ethanol condensation produced an inorganic alternating copolymer structure, Si–O–P, with a phosphole group, and successive polymerization between vinyl and/or methacryl groups enabled these structures to connect with each other. In this way, it is possible to achieve structure manufacturing of inorganic–organic networks. The proton conductivities of the hybrids are as high as 5.2 × 10−3 S/cm at 85 °C under 80% relative humidity.

The nano-scale strain fields analysis around 90° domains and misfit dislocations in PbTiO3/SrTiO3 001 epitaxial thin film has been conducted using the geometric phase analysis (GPA) combined with high angle annular dark field - scanning transmission electron microscopy (HAADF-STEM). The films typically possess a-c mixed domain configuration with misfit dislocations. The PbTiO3 layer was formed from the two layer: the upper 200 nm layer shows the typical a- and c- mixed domain configuration where the a-domains are several tens nm in width; the bottom 100 nm layer shows the different domain configuration that the width is several nm. In the latter case, a-domains are terminated within the film and are short in length. On the other hand, the bottom of a-domains does not contact the film/substrate interface. It keeps away from the interface, and there is completely c-domain layer under a-domains. The HAADF-STEM-GPA shows that the strain fields around an a-domain and a misfit dislocation interact each other: the tensile strain field and lattice plane bending fit together. This result indicates that the a-domain originates from the misfit dislocation.

Crystal structure change with the temperature was investigated for 3 m-thick (100)/(001)-oriented epitaxial PbTiO3 films grown on SrTiO3 substrates. Complex strain-relaxed domain structure labeled as Type III was observed and directly transformed to the cubic phase at about 490°C. This transition temperature and the lattice parameter (a and c- axes) change with the temperature well agreed with the reported data for the PbTiO3 powders. The volume fraction of the (001) orientations, Vc, was almost independent of the temperature up to the phase transition temperature. The tilting angles of the spots in XRD plan view were almost the same with the estimated ones from the lattice parameters and the Vc. This suggests that the angle of the domains identified by the domain structure in Type III. This structure is mainly determined by the tetragonality, (c/a ratio) and the Vc.

Recent experiments on ultrasonic measurements of non-doped and boron-doped silicon indicate that vacancies in crystalline silicon can be detected through the elastic softening at low temperature. This is attributed to enhanced response of electronic quadrupole localized at the vacancies to the elastic strain. In the present work, the electronic quadrupole moment of the vacancy orbital in silicon and their strain susceptibility are evaluated quantitatively by using the density-functional method. We show the orbital of gap state is localized around vacancy but extended over several neighbors. The effect of applied magnetic field on the vacancy orbital and its multipole structures are also investigated. We find that the results obtained from these calculations are consistent with the ultrasonic experiments.

Epitaxaially-grown KNbO3 thick films over 8 μm in thickness were successfully grown at 220 °C for 6 h on (100)cSrRuO3//SrTiO3 substrates by a hydrothermal method. Epitaxial SrRuO3 layers grown on (100)cSrTiO3 substrates by sputter method were used as bottom electrode layers. Relative dielectric constant and the dielectric loss were 530 and 0.11, respectively. Clear hysteresis loops originated to the ferreoelectricity were observed and a remanent polarization was 25 μC/cm2 at a maximum applied electric field of 540 kV/cm. In addition, the hydrothermal KNbO3 thick film was able to transmitting and receiving of ultrasonic waves over 50MHz.

Diamond is a promising semiconductor which shows some unique surface electronic features if grown optimized with low bulk and surface defect densities. The appearance of a highly conducting surface layer if immersed into electrolyte solution is maybe the most striking feature. Scanning tunneling microscopy experiments on diamond in electrolyte solutions are applied to determine the electronic properties governing these transition. These experiments reveal the formation of unoccupied quantized electronic states in the valence band close to the surface. A two-dimensional density of state distribution with three levels from light-, heavy-, and split-off-band holes is detected. Removal of the electrolyte causes a reversible transition into the insulating state and vice versa.

Miniaturized DNA sensitive field-effect transistors (DNA-FET) have been realized using single crystalline diamond grown by plasma-enhanced chemical vapor deposition (CVD). To bond DNA to diamond, amine linker-molecules are covalently attached by photochemical means to H-terminated diamond surfaces. Using hetero-bifunctional cross-linker and thiol-modified single-strand (ss) cancer marker DNA (CK20), the gate of diamond FETs is modified to sense hybridization of DNA, forming double-strand (ds) DNA molecules on the gate. The density of DNA bonded to diamond has been adjusted to about 1012 cm−2 and the experiments have been performed in phosphate buffer with different ionicity to control the Debye length of the Helmholtz layer. By hybridization, a gate-potential shift of 64 mV is detected in case of the 100 Å Debye lengths, while 46 mV is detected for 10 Å. This is discussed with respect to DNA related variations of charge and pH by hybridization. Time resolved experiments reveal exponential hybridization dynamics with a time constant of 600 s. The sensitivity limit of our experiment is about 1 nM.

We successfully measured the mechanoluminesence (ML) from a single ML nanoparticle at the first time. In order to measure the weak light emission from a single nanoparticle induced by applying a micro force, we developed an AFM-based new apparatus with a photomultiplier. Interestingly, the emission (ML) intensity from a nanoparticle was approximately proportional to the load, the phenomena is similar to the macroscopic ML emission properties.