Autofocus technique for three-dimensional imaging, direct-detection laser radar using Geiger-mode avalanche photodiode focal-plane array

An autofocus technique is proposed for a three-dimensional imaging, direct-detection laser radar system that uses a Geiger-mode avalanche photodiode focal plane array (GmAPD-FPA). This technique is implemented by pointing laser pulses on a target of interest and observing its scattered photon distribution on a GmAPD-FPA. Measuring the standard deviation of the photon distribution on a GmAPD-FPA enables the best focus condition to be found. The feasibility of this technique is demonstrated experimentally by employing a 1 × 8 pixel GmAPD-FPA. It is shown that the spatial resolution improves when the GmAPD-FPA is located in the best focus position found by the autofocus technique.     

Magnesium perchlorate anhydrate,Mg(ClO4)2, from laboratory X‐ray powder data

The previously unknown crystal structure of magnesium perchlorate anhydrate, determined and refined from laboratory X‐ray powder diffraction data, represents a new structure type. The title compound was obtained by heating magnesium perchlorate hexahydrate at 523 K for 2 h under vacuum and it crystallizes in the monoclinic space group P2₁/c. The asymmetric unit contains one Mg (site symmetry on special position 2a), one Cl and four O sites (on general positions 4e). The structure consists of a three‐dimensional network resulting from the corner‐sharing of MgO₆ octahedra and ClO₄ tetrahedra. Each MgO₆ octahedron share corners with six ClO₄ tetrahedra. Each ClO₄ tetrahedron shares corners with three MgO₆ octahedra, with one O‐atom corner dangling. The ClO₄ tetrahedra are oriented in such a way that one‐dimensional channels parallel to [100] are formed between the dangling O atoms.     

Wave-front phase measurements of high-order harmonic beams by use of point-diffraction interferometry

We report the wave-front phase measurement of high-order harmonics employing point-diffraction interferometry. The high-order harmonics generated in a gas-filled hollow tube showed excellent spatial coherence over nearly the whole cross section of the harmonic beams. Using this coherent harmonic source in the extreme-ultraviolet-soft-x-ray region, we have demonstrated the operation of a point-diffraction interferometer and measured the wave-front phase of high-order harmonics.     

Application of QPLEXTM biomarkers in cognitively normal individuals across a broad age range and diverse regions with cerebral amyloid deposition

The deposition of beta-amyloid (Aβ) in the brain precedes the onset of symptoms such as cognitive impairment in Alzheimer’s disease (AD); therefore, the early detection of Aβ accumulation is crucial. We previously reported the applicability of the QPLEX^TM Alz plus assay kit for the prescreening of Aβ accumulation. Here, we tested the specific application of the kit in a large cohort of cognitively normal (CN) individuals of varying ages for the early detection of Aβ accumulation. We included a total of 221 CN participants with or without brain Aβ. The QPLEX^TM biomarkers were characterized based on age groups (1^st–3^rd tertile) and across various brain regions with cerebral amyloid deposition. The 3^rd tertile group (>65 years) was found to be the most suitable age group for the application of our assay kit. Receiver operating characteristic curve analysis showed that the area under the curve (AUC, discrimination power) was 0.878 with 69.7% sensitivity and 98.4% specificity in the 3^rd tertile group. Additionally, specific correlations between biomarkers and cerebral amyloid deposition in four different brain regions revealed an overall correlation with general amyloid deposition, consistent with previous findings. Furthermore, the combinational panel with plasma Aβ1–42 levels maximized the discrimination efficiency and achieved an AUC of 0.921 with 95.7% sensitivity and 67.3% specificity. Thus, we suggest that the QPLEX^TM Alz plus assay is useful for prescreening brain Aβ levels in CN individuals, especially those aged >65 years, to prevent disease progression via the early detection of disease initiation.Subject terms: Alzheimer''s disease, Neural ageing, ELISA     

Abatement of Trichloromethane by Using Nonthermal Plasma Reactors

This work investigated the destruction of a halogenated carbon (trichloromethane) using different types of nonthermal plasma reactors. Three reactors, i.e., a surface discharge reactor, a dielectric-packed bed reactor and a barrier discharge reactor with a perforated dielectric tube, were compared with respected to the trichloromethane destruction efficiency. The effect of oxygen content and input power on the trichloromethane destruction was examined, and the byproducts were analyzed to elucidate the destruction pathways. The dielectric-packed bed reactor was found to show better performance in the trichloromethane destruction than the other two reactors. The increase in the oxygen content decreased the destruction efficiency, and the highest destruction efficiency was obtained at oxygen content 0.5%. The calculations for electron-molecule collisions indicated that the most abundant reactive species initiating the destruction of trichloromethane are metastable nitrogen molecules. The major byproducts were CO and Cl₂, and the formations of NO₂ and N₂O were also significant.     

An Edgeworth expansion for functionals of Gaussian fields and its applications

This paper is concerned with the rate of convergence in the normal approximation of the sequence $\left\{F_n\right\}$, where each $F_n$ is a functional of an infinite-dimensional Gaussian field. We develop new and powerful techniques for computing the exact rate of convergence in distribution with respect to the Kolmogorov distance. As a tool for our works, the Edgeworth expansion of general orders, with an explicitly expressed remainder, will be obtained, and this remainder term will be controlled to find upper and lower bounds of the Kolmogorov distance in the case of an arbitrary sequence $\left\{F_n\right\}$. As applications, we provide the optimal fourth moment theorem of the sequence $\left\{F_n\right\}$ in the case when $\left\{F_n\right\}$ is a sequence of random variables living in a fixed Wiener chaos or a finite sum of Wiener chaoses. In the former case, our results show that the conditions given in this paper seem more natural and minimal than ones appeared in the previous works.     

Colloidal rotation near the colloidal glass transition

We compare, using single-particle optical imaging, trajectories of rotation and translation for micron-sized spheres in index-matched colloidal suspensions near their glass transition. Rotational trajectories, while they show intermittent caged behavior associated with supercooled and glassy behavior, explore a sufficiently wider phase space such that in the averaged mean-square angular displacement there appears no plateau regime, but instead sub-Fickian angular diffusion that follows an apparent power law in time. We infer translation and rotation time constants, the former being the time to diffuse a particle diameter and the latter being the time to rotate a full revolution. Correlation between time constants increases with increasing volume fraction, but unlike the case for molecular glasses, the rotation time constant slows more weakly than the translation time.     

An Effective and Convenient Esterefication of Cephalospor in Derivatives by Using Quarternary Ammonium Salts as Catalysts

A method for preparing cephalosporin derivatives by reacting cephalosporin alkaline metal salts with organic halide in the presence of quarternary ammonium salts catalyst is disclosed. Δ³ to Δ² isomerization, a side reaction commonly reported in preparation of cephalosporin derivatives, was successfully eliminated. The desired Δ³ was obtained as a sole product in the reaction.     

Enhanced local density of states at the Fermi level of the surface platinum in carbon-supported platinum particles by Nafion ionomer

¹⁹⁵Pt nuclear magnetic resonance (NMR) was employed to study the influence of Nafion ionomers (NIs), a common ingredient used as a proton conducting mediator and binder in a membrane-electrode-assembly (MEA) for proton exchange membrane fuel cells, on the local density of states at the Fermi surface (E_F-LDOS) of Pt/C catalysts. NIs were observed to increase the surface E_F-LDOS of Pt particles, thereby altering of the catalytic properties of metal particles. This correlates well with the reduction of fuel oxidation rates. Thus, ionomers decreasing the surface E_F-LDOS of Pt particles would be desirable. In addition, a new concept to interpret the surface E_F-LDOS was introduced and validated.