Exploring uses of persistent homology for statistical analysis of landmark-based shape data

A method for the use of persistent homology in the statistical analysis of landmark-based shape data is given. Three-dimensional landmark configurations are used as input for separate filtrations, persistent homology is performed, and persistence diagrams are obtained. Groups of configurations are compared using distances between persistence diagrams combined with dimensionality reduction methods. A three-dimensional landmark-based data set is used from a longitudinal orthodontic study, and the persistent homology method is able to distinguish clinically relevant treatment effects. Comparisons are made with the traditional landmark-based statistical shape analysis methods of Dryden and Mardia, and Euclidean Distance Matrix Analysis.     

The role of sample collection method and the bias between different standard matrices in the determination of volatile organic compounds in air

This study was undertaken to assess the relative bias between two types of sampling methods for volatile organic compounds (VOCs), i.e., sorbent tube vs. bag sampling methods and between different standard phases. For the purpose of this comparative study, gaseous standards containing three major aromatic VOCs (benzene, toluene, and xylene—commonly called BTX) were analyzed by thermo-desorption gas chromatography (TD-GC) with flame ionization detector. According to our findings, the relative response of target compounds can be smaller in the bag method than in the tube method. Although the relative bias varies with the sample transfer conditions for the TD, the mean slope values of the former are smaller by up to 20% relative to the latter, possibly due to sorptive loss on the bag sampler. In addition, the effects of different standard matrices (i.e. liquid and gas phases) were also examined using the sorbent tube method. The results indicated that the slope values of the gas-phase standard were smaller by half (about 43–56%) than the liquid-phase standard. Consequently, information concerning the extent of relative bias between sampling methods (e.g., bag and tube) or standard matrices (e.g., gas and liquid) should be considered as one of the key factors in TD applications.     

Synthesis of zinc glutarates with various morphologies using an amphiphilic template and their catalytic activities in the copolymerization of carbon dioxide and propylene oxide

Various heterogeneous zinc glutarate (ZnGA) catalysts were synthesized in solvent systems of various polarities from zinc acetate dihydrate and glutaric acid with and without the aid of an amphiphilic block copolymer, poly(ethylene glycol‐b‐propylene glycol‐b‐ethylene glycol) (PE6400), as a template. The presence of the PE6400 template and the polarity of the solvent significantly affected the morphology, particle size, surface area, and crystallinity of the resulting catalyst. However, all the catalysts had the same crystal lattice unit cell structure and similar surface compositions. The surface compositions of the catalysts were quite different from those of conventionally prepared ZnGA catalysts, that is, those prepared from zinc oxide and glutaric acid in toluene. All these characteristics of the catalysts influenced the ZnGA‐catalyzed copolymerization of carbon dioxide and propylene oxide. The catalytic activities of the catalysts in this copolymerization depended primarily on their surface area and secondarily on their crystallinity; a larger surface area and a higher crystallinity resulted in higher catalytic activity. Of the catalysts that we prepared, the ZnGA catalyst that was prepared in ethanol containing 5.5 wt % water with the PE6400 template, ZnGA‐PE3, exhibited the highest catalytic activity in the copolymerization. The catalytic activity of ZnGA‐PE3 was attributed to its wrinkled petal bundle morphology, which provided a large surface area and high crystallinity. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4079–4088, 2005     

Common-intermediate strategy for synthesis of conduritols and inositols via beta-hydroxy cyclohexenylsilanes

[reaction: see text] Syntheses of conduritols B-D and F and d-(+)-chiro- and neo-inositols from cyclohexenylsilane intermediates are described. The key cyclohexylsilane intermediates 5 and 14 were synthesized by stereoselective olefin dihydroxylation of the corresponding cyclohexenylsilanes. Selective Peterson elimination reactions and Fleming-Tamao oxidations of 5 and 14 then delivered the targeted cyclitol derivatives.     

Highly efficient 1,4-addition of 1,3-diesters to conjugated enones by In/TMSCl

Organoindium reagents derived from indium and diethyl bromomalonates were added to a wide range of conjugated enones in a 1,4-fashion in the presence of TMSCl under mild conditions, and corresponding oxo-1,3-diesters were obtained in good to excellent yields.     

Preparation of cholesteric liquid crystal microcapsules for application in colour image storage media

Cholesteric liquid crystal (CLC) microcapsules for application in image storage media can be obtained via a diffusion-controlled polymerization method (DPM). To improve the swelling of the CLC seed particle, in poly(methylmethacrylate) (PMMA), a polymerizable acrylate based on a cholesterol moiety was synthesized and copolymerized with MMA to prepare the seed particle. As a result, monodispersed and CLC core/shell-structured microcapsules may be obtained. The resulting CLC microcapsules selectively, absorbed visible light at around 660 nm, and so appeared blue in the mesophase. Polymer dispersed cholesteric liquid crystal (PDCLC) cells were prepared using the CLC microcapsules, and were used as an image storage medium in reversible writing/erasing experiments.     

Single-stage anaerobic codigestion for mixture wastes of simulated Korean food waste and waste activated sludge

Korean food waste was treated with a single-stage anaerobic codigester (SSAD) using waste activated sludge (WAS) generated from a municipal wastewater treatment plant. The stability and performance of the system was analyzed. The C/N ratio was improved with increasing food waste fraction of feed mixture. The pH, alkalinity, and free ammonia nitrogen concentration were the parameters used to evaluate the digester’s stability. The experimentally determined values of the parameters indicated that there were no methane inhibitions in the digester. Digester performance was determined by measuring the total chemical oxygen demand TCOD), volate solids (VS) removal, methane content in biogas, methane production rate (MPR), and specific methane productivity. Methane content in biogas and MPR were significantly dependent on hydraulic retention time (HRT) and ratio of food waste to WAS. The methane content in biogas decreased at shorter HRT or higher organic loading rate (OLR) with increased food waste fraction. Concerning the performance of the codigester, the optimum operating condition of the SSAD was found to be at an HRT of 10 d with a feed mixture ratio of 50% food waste and 50% WAS. A TCOD removal efficiency of 53.6% and a VS removal efficiency of 53.7% were obtained at an OLR of 5.96 kg of TCOD/(m³·d) and 3.14 kg of VS/(m³·d), respectively. A maximum MPR of 1.15 m³ CH₄/(m³·d) and an SMP of 0.37 m³ CH₄/kg of VS_feed were obtained at an HRT of 10 d with a methane content of 63%.     

Odd-even behavior of ferroelectricity and antiferroelectricity in two homologous series of bent-core mesogens

Two chiral bent-core mesogens Pn-O-PIMB(n - 2)* (n = 9 and 10) and their oxygen analogues Pn-O-PIMB(n - 2)*-(n - 4)O (n = 8, 9, and 10) with omega-[(S)-amyloxy]alkoxy terminal groups were prepared, and their phase structures were investigated by means of electro-optic, polarization reversal current and second harmonic generation measurements in order to clarify the effect of the interlayer steric interaction on the emergence of polar orderings. The odd-even behavior for the alternative appearance of ferroelectricity and antiferroelectricity was observed in two homologous series; the bent-core mesogens P10-O-PIMB8*, P8-O-PIMB6*-4O, and P10-O-PIMB8*-6O in addition to the previously reported P6-O-PIMB4* and P8-O-PIMB6*, where the length of chains n is even, exhibited ferroelectric phases. On the contrary, the mesogens P7-O-PIMB5*, P9-O-PIMB7*, and P9-O-PIMB7*-5O, where n is odd, showed antiferroelectric phases. It is obvious that the interlayer steric interaction plays a major role for the emergence of a variety of phase structures.     

Approaches to the fully functionalized DEF ring system of ristocetin A via highly selective ruthenium-promoted S(N)Ar reaction

Ruthenium-promoted intramolecular S(N)Ar reaction has allowed the construction of the fully functionalized 16-membered DEF macrocycle 4 of ristocetin A that incorporates the required arylglycine and arylserine residues as the F and E ring, respectively.