Concentration-dependence of faradaic currents and conductivity in a polystyrene sulfonic latex suspension

The conductivity, κ, in a suspension of polystyrene sulfonic latex without supporting electrolyte showed a linear dependence on the volume fraction, v_f, of the latex for v_f<0.03 with a finite intercept. In contrast, this deviated upward from the linear line for v_f>0.03. These variations were qualitatively consistent with the dependence of the voltammetric reduction current of H⁺ on v_f without supporting electrolyte. The current values were only a few percent of the theoretical diffusion-controlled current that could be observed in the suspension with supporting electrolyte. This fact indicates the electrostatic immobilization of the hydrogen ions by sulfonic latex particles. A plot of the current against κ at common values of v_f showed that the current for v_f>0.07 was smaller than the value predicted from the conductivity. This can be explained in terms of a combination of the increase in electrostatically unbounded H⁺ estimated by conductance measurements and electric migration in which the electrochemical depletion of [H⁺] also causes the depletion of the latex.     

Acoustic characteristics of rough voice: Subharmonics

This study investigates the relationship between rough voice and the presence of Subharmonics, which correspond to smaller yet distinct peaks located between two consecutive harmonic peaks in the power spectrum. Spectrum analysis was undertaken in 389 pathologic voices, of which 20 had subharmonics. Although all 20 voices had roughness perceptually, 8 had normal jitter and/or shimmer. The degree of roughness had a significant inverse relationship with the frequency of subharmonics. By digital signal processing, sound samples with various types of subharmonics were synthesized and perceptually analyzed. Power and frequency of subharmonics in the synthesized sound also had significant relationships with the degree of roughness. Rough voice is acoustically characterized not only by jitter and shimmer but also by the presence of subharmonics in the power spectrum. Subharmonics are important acoustic properties for objective evaluation of rough voices.     

Sequential Upscaling Method

This paper presents a new method for scaling up multiphase flow properties which properly accounts for boundary conditions on the upscaled cell. The scale-up proposed does not require the simulation of a complete finely-gridded model, instead it calls for assumptions allowing the calculation of the boundary conditions related to each block being scaled up. To upscale a coarse block, we have to assume or determine the proper boundary conditions for that coarse block. To date, most scale-up methods have been based on the assumption of steady-state flow associated with uniform fractional flows over all the boundaries of the coarse block. However, such an assumption is not strictly valid when we consider heterogeneities. The concept of injection tubes is introduced: these are hypothetical streamtubes connecting the injection wellbore to all inlet faces of the fine grid cells constituting the block to be scaled up. Injection tubes allow the capturing of the fine-scale flow behavior of a finely-gridded model at the inlet face of the coarse block without having to simulate that fine grid. We describe how to scale up an entire finely-gridded model sequentially using injection tubes to determine the boundary conditions for two-phase flow. This new scale-up method is able to capture almost exactly the fine-scale two-phase flow behavior, such as saturation distributions, inside each isolated coarse-grid domain. Further, the resultant scaled-up relative permeabilities reproduce accurately the spatially-averaged performance of the finely-gridded model throughout the simulation period. The method has been shown to be applicable not only to viscous-dominated flow but also to flow affected by gravity for reasonable viscous-to-gravity ratios.     

Reconstitution of Biosynthetic Machinery for the Synthesis of the Highly Elaborated Indole Diterpene Penitrem

Penitrem A is one of the most elaborated members of the fungal indole diterpenes. Two separate penitrem gene clusters were identified using genomic and RNA sequencing data, and 13 out of 17 transformations in the penitrem biosynthesis were elucidated by heterologous reconstitution of the relevant genes. These reactions involve 1) a prenylation‐initiated cationic cyclization to install the bicyclo[3.2.0]heptane skeleton (PtmE), 2) a two‐step P450‐catalyzed oxidative processes forming the unique tricyclic penitrem skeleton (PtmK and PtmU), and 3) five sequential oxidative transformations (PtmKULNJ). Importantly, without conventional gene disruption, reconstitution of the biosynthetic machinery provided sufficient data to determine the pathway. It was thus demonstrated that the Aspergillus oryzae reconstitution system is a powerful method for studying the biosynthesis of complex natural products.     

Precise determination of bromine in PP resin pellet by instrumental neutron activation analysis using internal standardization

Instrumental neutron activation analysis with the internal standardization was applied to the precise determination of Br in polypropylene resin of candidate certified reference material. The known amount of ¹⁹⁷Au was used as an internal standard to compensate for neutron flux inhomogeneity, to improve the γ ray measurement uncertainty and the linearity of the calibration curves. The reliability of the proposed method validated using analytical results of BCR-681. The analytical result of Br in the sample was consistent with that obtained by ID-ICPMS. The relative expanded uncertainty (k = 2) was 1.5 %, and it was equivalent to that of ID-ICPMS.     

A novel approach for LC-MS/MS-based chiral metabolomics fingerprinting and chiral metabolomics extraction using a pair of enantiomers of chiral derivatization reagents

Chiral metabolites are found in a wide variety of living organisms and some of them are understood to be physiologically active compounds and biomarkers. However, the overall analysis of chiral metabolomics is quite difficult due to the high number of metabolites, the significant diversity in their physicochemical properties, and concentration range from metabolite-to-metabolite. To solve this difficulty, we developed a novel approach for chiral metabolomics fingerprinting and chiral metabolomics extraction, which is based on the labeling of a pair of enantiomers of chiral derivatization reagents (i.e., DMT-(S,R)-Pro-OSu and DMT-3(S,R)-Apy) and precursor ion scan chromatography of the derivatives. The multivariate statistics is also required for this strategy. The proposed procedures were evaluated by the detection of a diagnostic marker (i.e., d-lactic acid) using the saliva of diabetic patients. This method was used for the determination of biomarker candidates of chiral amines and carboxyls in Alzheimer's disease (AD) brain homogenates. As the results, l-phenylalanine (L-Phe) and l-lactic acid (L-LA) were identified as the decreased and increased biomarker candidates in the AD brain, respectively. Therefore, the proposed approach seems to be helpful for the determination of non-target chiral metabolomics possessing amines and carboxyls.     

Towards the chiral metabolomics: Liquid chromatography–mass spectrometry based dl-amino acid analysis after labeling with a new chiral reagent, (S)-2,5-dioxopyrrolidin-1-yl-1-(4,6-dimethoxy-1,3,5-triazin-2-yl)pyrrolidine-2-carboxylate,and the application to saliva of healthy volunteers

A novel triazine-type chiral derivatization reagent, i.e., (S)-2,5-dioxopyrrolidin-1-yl-1-(4,6-dimethoxy-1,3,5-triazin-2-yl) pyrrolidine-2-carboxylate (DMT-(S)-Pro-OSu), was developed for the highly sensitive and selective detection of chiral amines and amino acids by UPLC–MS/MS analysis. The enantiomers of amino acids were easily labeled with the reagents at room temperature within 40 min in an alkaline medium containing triethylamine. The diastereomers derived from proteolytic amino acids, except serine, were well separated under isocratic elution conditions by reversed-phase chromatography using an ODS column (R_s = 1.2–9.0). dl-Serine was separated by use of an ADME column which has relatively higher polar surface than the conventional ODS column. The characteristic product ions, i.e., m/z 195.3 and m/z 209.3, were detected from all the diastereomers by the collision-induced dissociation of the protonated molecule. A highly sensitive detection on the amol–fmol level was obtained from the selected reaction monitoring (SRM) chromatogram. The chiral amines (e.g., adrenaline and noradrenaline) labeled with DMT-(S)-Pro-OSu were also well separated and sensitively detected by the present procedure. The method using DMT-(S)-Pro-OSu was used for the determination of dl-amino acids in the human saliva from healthy volunteers. Various l-amino acids were identified in the saliva. Furthermore, d-alanine (d-Ala) and d-proline (d-Pro) were also detected in relatively high concentrations (>5%). The ratio was higher in male saliva than in female saliva. However, the difference in the ratio of d-Ala for one day was not very high and the effect of foods and beverage seemed to be negligible. Based on the results using l-Ala-d₃, the d-Ala in saliva seemed to be produced due to the racemization with some enzymes such as racemase. The racemization reaction was reversible, i.e., d-Ala-d₃ was also racemized to l-Ala-d₃ in saliva. Thus, care should be taken during the analysis of dl-amino acids in saliva. The present method using DMT-(S)-Pro-OSu may be applicable for the determination of chiral amine metabolomics, because the resulting derivatives produce the same product ions without relation to the compounds and show highly sensitive detection in the SRM mode of MS/MS. Consequently, DMT-(S)-Pro-OSu seems to be a useful chiral derivatization reagent for the determination of amines and amino acids in biological samples.     

Coronenetetraimide‐Centered Cruciform Pentamers Containing Multiporphyrin Units: Synthesis and Sequential Photoinduced Energy‐ and Electron‐Transfer Dynamics

A series of coronenetetraimide (CorTIm)‐centered cruciform pentamers containing multiporphyrin units, in which four porphyrin units are covalently linked to a CorTIm core through benzyl linkages, were designed and synthesized to investigate their structural, spectroscopic, and electrochemical properties as well as photoinduced electron‐ and energy‐transfer dynamics. These systems afforded the first synthetic case of coroneneimide derivatives covalently linked with dye molecules. The steady‐state absorption and electrochemical results indicate that a CorTIm and four porphyrin units were successfully characterized by the corresponding reference monomers. In contrast, the steady‐state fluorescence measurements demonstrated that strong fluorescence quenching relative to the corresponding monomer units was observed in these pentamers. Nanosecond laser flash photolysis measurements revealed the occurrence of intermolecular electron transfer from triplet excited state of zinc porphyrins to CorTIm. Femtosecond laser‐induced transient absorption measurements for excitation of the CorTIm unit clearly demonstrate the sequential photoinduced energy and electron transfer between CorTIm and porphyrins, that is, occurrence of the initial energy transfer from CorTIm (energy donor) to porphyrins (energy acceptor) and subsequent electron transfer from porphyrins (electron donor) to CorTIm (electron acceptor) in these pentamers, whereas only the electron‐transfer process from porphyrins to CorTIm was observed when we mainly excite porphyrin units. Finally, construction of high‐order supramolecular patterning of these pentamers was performed by utilizing self‐assembly and physical dewetting during the evaporation of solvent.     

Reversible strain gage

A reversible strain gage was developed for accurately measuring thermal strains, especially for use on large structures where strain gages cannot be welded. These strain gages can be peeled after taking required apparentstrain measurements in a furnace and can be attached reverse-side-up at the points of interest on a test structure. After many trials, a polyimide strain gage was developed that is the same on both the base side and the cover side. The thermal characteristics of the reversible strain gage—repeatability of apparent strain, gage-factor change, creep, drift and the output for a given mechanical strain—were investigated. The repeatability of apparent strains for 100 reversible gages was within 60 microstrain of difference at 250°C. The output of reversible gages for mechanical strain, after 2 to 3 heat cycles which were peeled and cemented in the reverse-side-up position, almost coincided with those of virgin reversible gages.Paper was presented at Fourth SESA International Congress on Experimental Mechanics held in Boston, MA on May 25–30, 1980