A note on determinants,minors and a boundary map

We give an explicit formula for the first non-trivial boundary map of the Akin–Buchsbaum–Weyman resolution (Schur functors and Schur complexes, Adv. Math 1982;44:207-278). The role of the Laplace expansion formula is emphasized.     

CFD-PBM approach for the gas-liquid flow in a nanobubble generator with honeycomb structure

In recent years, nanobubble technologies have drawn great attention due to their wide applications in many fields of science and technology. From previous studies, a kind of honeycomb structure for high efficiency nanobubble generation has been proposed. In this paper, the numerical simulations of bubbly flow in the honeycomb structure were performed by using a computational fluid dynamics–population balance model (CFD-PBM) coupled model. The numerical model was based on the Eulerian multiphase model and the population balance model (PBM) was used to calculate the bubble size distribution. The bubble size distributions in the honeycomb structure under different work conditions were predicted. Two different drag force models (Schiller-Naumann model and Tomiyama model) and two different aggregation models (Luo model and turbulent aggregation model) were investigated. Both two drag models gave similar prediction of bubble number density distribution at the outlet. The results obtained from Luo model had better reflection of the trend of number density distribution. The turbulence dissipation rate ε can be used to evaluate the nanobubble generating ability. The water tank was not included in the CFD model in this work. The bubbles in the water tank should be studied in the future.     

Investigation of the cosmetic ingredient distribution in the stratum corneum using NanoSIMS imaging

In order to understand the mechanisms of action of cosmetic ingredients, it is important to establish the distribution of the component agents within the epidermis of the skin. To date, time-of-flight secondary ion mass spectrometry (TOF-SIMS) has been used to detect cosmetic ingredients in the skin. However, it is technically difficult to investigate the distribution of the agents in the stratum corneum using TOF-SIMS. Therefore, an analytical method with higher spatial resolution is required. In this study, we investigated an imaging analysis technique based on NanoSIMS to detect cosmetic ingredients in the skin. Pig skin was used as a model for human skin. The sample was treated with a cosmetic formulation containing ¹⁵N-labelled pseudo-ceramide (SLE). The sample was frozen with liquid nitrogen and cross-sections were cut using a cryomicrotome. As a result, the fine layer structure of the corneocytes was clearly observed by using NanoSIMS. Our studies indicate that SLE penetrates into the stratum corneum via an intercellular route. We conclude that application of NanoSIMS analysis can contribute to a better understanding of the function of cosmetic ingredients in the skin.     

Ion extraction from the surface ablated materials in electric fields using an intense femtosecond laser pulse

In order to develop a femtosecond laser ablation (fsLA) ion source for TOF mass spectrometry, we have analyzed time-resolved images of laser-induced fluorescence from Sm⁺ ions produced by fsLA of a solid samarium in electric fields. The polarity and the strength of electric fields had a remarkable effect on the expansion of Sm⁺ ions. Moreover, accelerating electric fields elongated the duration of the ion emission from the samarium surface in fsLA, which degraded time-focusing of the ions. We have found that suppression the continuous ion emission caused by fsLA in electric fields is most important in TOF measurements.     

Synthesis and Structural Characterization of Isomers of Ru-Substituted Keggin-Type Germanotungstate with dmso Ligand

We found that three isomers of mono-Ru substituted Keggin-type germanotungstate with a dmso ligand, [GeW₁₁O₃₉Ru^II(dmso)]^6?, could be formed by a reaction of α-Keggin-type mono-lacunary germanotungstate, [α-GeW₁₁O₃₉]^8?, with Ru(dmso)₄Cl₂. The main isomer is an α-isomer, and the others are β₂-isomer and β₃-isomer, which were confirmed by ¹H NMR, cyclic voltammetry, IR, and single crystal X-ray structure analysis.     

Am,Cm recovery from genuine HLLW by extraction chromatography

Journal of Radioanalytical and Nuclear Chemistry - The extraction chromatography experiments for Am(III) and Cm(III) recovery from genuine HLLW were carried out in order to demonstrate modified 2...     

Total Synthesis of the Nonribosomal Peptide Surugamide B and Identification of a New Offloading Cyclase Family

The cathepsin B inhibitor surugamide B ( 2 ), along with structurally related derivatives (A and C–E), has previously been isolated from the marine actinomycete Streptomyces sp. JAMM992. The biosynthetic genes are unexpectedly part of a cluster of four non‐ribosomal peptide synthetase (NRPS) genes, two of which are responsible for the biosynthesis of the additional linear decapeptide surugamide F. However, the thioesterase domain required for the later stage of the biosynthesis of the cyclic peptides surugamides A–E is not present in any module architecture of the surugamide NRPSs. Herein, we report the first total synthesis of surugamide B ( 2 ) through the macrocyclization at the biomimetic position, which not only alleviated the Cα epimerization in the macrolactamization process, but also efficiently provided 2 in 34 % yield for 18 steps. Furthermore, both the chemical and enzymatic studies with the biosynthetic precursor mimics revealed that the stand‐alone enzyme SurE, which belongs to the penicillin‐binding protein family, is responsible for macrocyclization of the tethered octapeptidyl intermediate.     

Transmission electron microscopy observation of GaAs/Al0.3Ga0.7As T-shaped quantum well structure fabricated by glancing angle molecular beam epitaxy on GaAs(100) reverse-mesa etched substrates

GaAs/Al_0.3Ga_0.7As multi-layer structures were grown on GaAs (100) reverse-mesa etched substrates by glancing angle molecular beam epitaxy (GA-MBE). A(111)B facet was formed as a side-facet. Surface migration of Ga and Al atoms from the (100) flat region to the (111)B side-facet region has been investigated to fabricate T-shaped GaAs/AlGaAs quantum wells (QWs) under the condition that Ga and Al atoms impinge only an the (100) flat region and do not impinge on the (111)B side-facet. Observation of T-shaped GaAs/AlGaAs quantum wires (QWRs) by cross-sectional transmission electron microscopy (TEM) revealed that there is no migration of Al atoms from the (100) to the (111)B facet region at a substrate temperature (T_s) as high as 630°C, under a V/III ratio of 28 (in pressure ratio). On the other hand, very thin GaAs epitaxial layers grown on the (111)B side-facet region owing to the Ga migration were observed for substrate temperatures of 600 and 630°C. It was found that the mass flow of Ga atoms from the (100) region to the (111)B side-facet region increases, with the thermal activation energy of 2.0 eV, as the substrate temperature increases from 570 to 630°C. The GA-MBE growth on a reverse-mesa etched GaAs substrate at a low temperature 570°C or lower is desirable to fabricate a nm-scale GaAs/AlGaAs QWR structure with nm-scale precision.     

Preferential migration of indium atoms on the (411)A plane in InGaAs grown on GaAs channeled substrates by molecular beam epitaxy

Lateral profiles of In content in a 1.5 μm thick In_xGa_1−xAs (x 0.2) layer grown on GaAs channeled substrates (CSs) with (411)A side-slopes by molecular beam epitaxy (MBE) have been investigated with the use of energy dispersive X-ray spectroscopy (EDX). The observed profiles of the In content suggested that In atoms migrate preferentially in the [1 ] direction on the (411)A plane during MBE growth. This preferential migration of In atoms along [1 ] on the (411)A plane was confirmed by comparing observed lateral profiles of In content in InGaAs layers grown on GaAs CSs and simulated In profiles which are calculated by taking into account of an additional one-way flow of In atoms along [1 ].     

Deduction of channel-length distribution from isothermal thermogravimetry

A possible deduction is proposed of channel length distribution in one-dimensional porous materials from the kinetic data obtained in isothermal thermogravimetry (TG). The method utilizes the absorption/desorption of small molecules into one-dimensional nano-channel. In the surface-controlled absorption/desorption, the second derivative with respect to time is directly proportional to the channel-length distribution function. Even in the diffusion-controlled case, the second derivative with respect to the square root of time gives rough information on the distribution function.