Baseline noise and measurement uncertainty in liquid chromatography.

The stochastic properties of baseline noise in HPLC systems with a UV photo-diode array, photo-multiplier and gamma-ray detector were examined by dividing the noise into auto-correlated random process (Markov process) and an independent process (white noise). The present work focused on the effect of the stochastic noise properties on a theoretical estimation of the standard deviation (SD) of area measurements in instrumental analyses. An estimation theory, called FUMI theory (Function of Mutual Information), was taken as an example. A computer simulation of noise was also used. It was shown that the reliability (confidence intervals) of theoretical SD estimates mainly depends on the following factors: the ratio of the white noise and Markov process occurring in the baselines; the number of data points used for the estimation; the width of a target peak for which the SD is estimated.     

Minkowski’s Second Theorem over a Simple Algebra

We generalize the notion of successive minima, Minkowski’s second theorem and Siegel’s lemma to a free module over a simple algebra whose center is a global field.     

A note on asymptotic solutions for heat transfer in laminar forced flow against a non-isothermal rotating disk

Exact asymptotic expansions for heat transfer in laminar forced flow against a non-isothermal rotating disk are obtained for large and small Prandtl numbers using a perturbation method. The surface temperature of the disk is assumed to vary according to a power law with the radial distance. The results point out the erroneous terms in the existing asymptotic solutions and give the further higher order corrections to them.

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Zusammenfassung Mit Hilfe einer Störungsmethode werden exakte asymptotische Entwicklungen für den Wärmeübergang in laminarer Zwangskonvektion gegen eine nichtisotherme rotierende Scheibe für kleine und große Prandtl-Zahlen erhalten. Die Oberflächentemperatur soll nach einem Potenzgesetz vom Radius abhängen. Die Ergebnisse zeigen die Fehler in den bisherigen Lösungen auf und geben die Korrekturen höherer Ordnung.

     

Glycyl-alanyl-histidine protects PC12 cells against hydrogen peroxide toxicity

Background

Peptides with cytoprotective functions, including antioxidants and anti-infectives, could be useful therapeutics. Carnosine, β-alanine-histidine, is a dipeptide with anti-oxidant properties. Tripeptides of Ala-His-Lys, Pro-His-His, or Tyr-His-Tyr are also of interest in this respect.

Results

We synthesized several histidine-containing peptides including glycine or alanine, and tested their cytoprotective effects on hydrogen peroxide toxicity for PC12 cells. Of all these peptides (Gly-His-His, Ala-His-His, Ala-His-Ala, Ala-Ala-His, Ala-Gly-His, Gly-Ala-His (GAH), Ala-His-Gly, His-Ala-Gly, His-His-His, Gly-His-Ala, and Gly-Gly-His), GAH was found to have the strongest cytoprotective activity. GAH decreased lactate dehydrogenase (LDH) leakage, apoptosis, morphological changes, and nuclear membrane permeability changes against hydrogen peroxide toxicity in PC12 cells. The cytoprotective activity of GAH was superior to that of carnosine against hydrogen peroxide toxicity in PC12 cells. GAH also protected PC12 cells against damage caused by actinomycin D and staurosporine. Additionally, it was found that GAH also protected SH-SY5Y and Jurkat cells from damage caused by hydrogen peroxide, as assessed by LDH leakage.

Conclusion

Thus, a novel tripeptide, GAH, has been identified as having broad cytoprotective effects against hydrogen peroxide-induced cell damage.

     

Effect of Acid Treatment of Montmorillonite on “Support‐Activator” Performance to Support Metallocene for Propylene Polymerization Catalyst

This work is focused on montmorillonite (MMT)‐based “support‐activators” (S‐As) for the metallocene‐catalyzed propylene polymerization. This catalyst was previously industrialized; however, for further technological advances, the activation mechanism is investigated. The chemical and morphological requirements of the S‐A are surveyed using both commercially available raw clay minerals (non‐acid‐treated) and acid‐treated clay minerals. The S‐A possessing strong‐acid sites (pK a < ?8.2) gives a highly active catalyst. Acid treatment of MMT induces morphological changes as well as the formation of strong acid sites. Based on pore size distribution analysis and atomic force microscopy observations, it is concluded that the strong acid sites are located in the small pores around the edge of the clay mineral (not in the interlayer), where the structure is disordered by the acid treatment.

     

Multi-poly-Bernoulli numbers and polynomials with a <Emphasis Type="Italic">q</Emphasis> parameter

We introduce themulti-poly-Bernoulli numbers and polynomialswith a q parameter, which are generalizations of the poly-Bernoulli numbers and polynomials with a q parameter, respectively.We give several combinatorial identities and properties of these new numbers and polynomials.     

Complementary Euler numbers

For an integer k, define poly-Euler numbers of the second kind \(\widehat{E}_n^{(k)}\) (\(n=0,1,\ldots \)) by

$$\begin{aligned} \frac{{\mathrm{Li}}_k(1-e^{-4 t})}{4\sinh t}=\sum _{n=0}^\infty \widehat{E}_n^{(k)}\frac{t^n}{n!}. \end{aligned}$$

When \(k=1\), \(\widehat{E}_n=\widehat{E}_n^{(1)}\) are Euler numbers of the second kind or complimentary Euler numbers defined by

$$\begin{aligned} \frac{t}{\sinh t}=\sum _{n=0}^\infty \widehat{E}_n\frac{t^n}{n!}. \end{aligned}$$

Euler numbers of the second kind were introduced as special cases of hypergeometric Euler numbers of the second kind in Komatsu and Zhu (Hypergeometric Euler numbers, 2016, arXiv:1612.06210), so that they would supplement hypergeometric Euler numbers. In this paper, we study generalized Euler numbers of the second kind and give several properties and applications.

     

Application of partial-filling capillary electrophoresis using lectins and glycosidases for the characterization of oligosaccharides in a therapeutic antibody

Oligosaccharides in therapeutic recombinant antibodies play important roles in regulation of various biological functions. To monitor the glycosylation profiles of antibody pharmaceuticals in the manufacturing process, a highly sensitive and specific method is required. We extended partial-filling techniques using lectins and exoglycosidases in capillary electrophoresis for the characterization of 8-aminopylene-1,3,6-trisulfonic acid labeled N-linked oligosaccharides derived from the therapeutic antibody rituximab. In the lectin-filling method, Galb1–4GlcNAc-specific Erythrina cristagali agglutinin, a1, 6-linked Fuc-specific Aleuria aurantia lectin and Neu5Aca2–3Gal-specific Maackia amurensis lectin were used. The oligosaccharides migrated through the lectin plug during separation; the changes in separation profiles were observed according to the interaction with the lectins. The glycosidase-filling method allowed rapid digestion as suggested by the electropherograms. Partial-filling CE methods can avoid tedious hands-on procedures such as overnight incubation and optimization reaction condition with lectins and exoglycosidases. Combination of these partial-filling capillary electrophoresis methods makes the characterization of oligosaccharide profiles of therapeutic antibodies easier and faster.     

Syntheses, properties and applications of periodic mesoporous organosilicas prepared from bridged organosilane precursors

Periodic mesoporous organosilicas (PMOs) prepared by surfactant-directed polycondensation of bridged organosilane precursors are promising for a variety of next-generation functional materials, because their large surface areas, well-defined nanoporous structures and the structural diversity of organosilica frameworks are advantageous for functionalization. This critical review highlights the unique structural features of PMOs and their expanding potential applications. Since the early reports of PMOs in 1999, various synthetic approaches, including the selection of hydrolytic reaction conditions, development of new precursor compounds, design of templates and the use of co-condensation or grafting techniques, have enabled the hierarchical structural control of PMOs from molecular- and meso-scale structures to macroscopic morphology. The introduction of functional organic units, such as highly fluorescent π-conjugates and electroactive species, into the PMO framework has opened a new path for the development of fluorescent systems, sensors, charge-transporting materials and solid-state catalysts. Moreover, a combinational materials design approach to the organosilica frameworks, pore wall surfaces and internal parts of mesopores has led to novel luminescent and photocatalytic systems. Their advanced functions have been realized by energy and electron transfer from framework organics to guest molecules or catalytic centers. PMOs, in which the precise design of hierarchical structures and construction of multi-component systems are practicable, have a significant future in a new field of functional materials (93 references).