Biomimetic PLGA sensor: proof of principle and application

Abstract  

Spoilage of products can mainly be attributed to microorganisms which “live on the product”, i.e. which are able to utilize and/or metabolize components and/or molecules of the product. The objective of this work was to develop and optimize sensor prototypes indicating the quality of a product “in real time”, i.e. at the time the consumer is looking at the product. The design of the presented sensors relates to optical phenomena, for example anomalous absorption and remission of light. The crucial point of the sensor prototypes is a layer sensitive to the analyte, a polymer degradable by enzymes produced by the respective microorganisms. After incubation of the sensor setup with contaminated products, the lytic enzymes released from decaying cell material change the thickness of the polymer layer and generate a colour change visible by the naked eye. Production of the sensor prototypes is very simple and inexpensive and they might be successfully integrated into product packaging.     

High-quality alloyed CdSxSe1-x whiskers as waveguides with tunable stimulated emission

High-quality ultra-long alloyed CdS(x)Se(1)(-)(x) (0 < or = x < or = 1) whiskers were obtained by a simple thermal evaporation route. The near band-edge emission in these whiskers can be effectively guided at the sub-millimeter scale under continuous-wave laser excitation. As good optical waveguide cavities, the whiskers exhibit stimulated emissions under pulsed light excitation at room temperature for all compositions 0 < or = x < or = 1. The spectral positions of the sharp emission lines of the whiskers were tuned by their compositions, covering the spectral range from green to red.     

Markov Processes Related with Dunkl Operators

Dunkl operators are parameterized differential-difference operators on ^Nthat are related to finite reflection groups. They can be regarded as a generalization of partial derivatives and play a major role in the study of Calogero–Moser–Sutherland-type quantum many-body systems. Dunkl operators lead to generalizations of various analytic structures, like the Laplace operator, the Fourier transform, Hermite polynomials, and the heat semigroup. In this paper we investigate some probabilistic aspects of this theory in a systematic way. For this, we introduce a concept of homogeneity of Markov processes on ^Nthat generalizes the classical notion of processes with independent, stationary increments to the Dunkl setting. This includes analogues of Brownian motion and Cauchy processes. The generalizations of Brownian motion have the càdlàg property and form, after symmetrization with respect to the underlying reflection groups, diffusions on the Weyl chambers. A major part of the paper is devoted to the concept of modified moments of probability measures on ^Nin the Dunkl setting. This leads to several results for homogeneous Markov processes (in our extended setting), including martingale characterizations and limit theorems. Furthermore, relations to generalized Hermite polynomials, Appell systems, and Ornstein–Uhlenbeck processes are discussed.     

Synthesis of annulated dioxins as electron-rich donors for cation radical salts

The synthesis of a series of new alkoxylated linearly annulated dioxins is described together with their cyclic voltammetric behavior and some preliminary result on their ability to form cation radical salts. Of these dioxins, seven (8, 12, 19, 21, 27, 33, 34) are the first representatives of entirely new heterocyclic systems. Dioxins 8, 21, 22 and 27 gave good quality cation radical salts upon electrocrystallization.     

Photomodulation of Oxidative Metabolism and Electron Chain Enzymes in Rat Liver Mitochondria

Abstract— Low-level laser irradiation has been applied in a variety of laboratory studies and clinical trials for photobiostimulation over the last three decades. Considerable skepticism exists regarding the concept of photostimulation within the medical community. One of the major difficulties with photoirradiation research is that it lacks experimentally supportable mechanisms for the alleged photobiostimulatory effects. This study was undertaken to determine whether oxidative metabolism and electron chain enzymes in rat liver mitochondria can be modulated by photoirradiation. Oxygen consumption, phosphate potential, and energy charge of rat liver mitochondria were determined following photoirradiation. Activities of mitochondrial enzymes were analyzed to assess the specific enzymes that are directly involved with the photostimulatory process. An argon-dye laser at a wavelength of 660 nm and at a power density of 10 mW/cm² was used as a photon source. Photoirradiation significantly increased oxygen consumption (0.6 J/cm² and 1.2 J/cm², P < 0.05), phosphate potential, and the energy charge (1.8 J/cm² and 2.4 J/cm², P < 0.05) of rat liver mitochondria and enhanced the activities of NADH: ubiquinone oxidoreductase, ubiquinol: ferricytochrome C oxidoreductase and ferrocytochrome C: oxygen oxidoreductase (0.6 J/cm², 1.2 J/cm², 2.4 J/cm² and 4.8 J/cm², P < 0.05). The activities of succinate ubiquinone oxidoreductase, ATPase, and lactate dehydrogenase were not affected by photoirradiation.     

Influence of fillers and additives on the cure kinetics of an epoxy/anhydride resin

The cure kinetics of a cycloaliphatic epoxy resin with and without additives and cured with an anhydride hardener was investigated by isothermal and nonisothermal differential scanning calorimetry (DSC).Dynamic measurements were used to predict the total heat of reaction of the epoxy resin as well as its activation energy based on the methods of Kissinger and Ozawa. With these methods the inhibition and acceleration effects of additives and fillers on the kinetics have been demonstrated. Additives for advanced processing and property upgrade were added in less than 2 wt.%, whereas fillers on base of SiO₂ were incorporated in more than 50 wt.%. The effect of SiO₂ surface treatment was also objective of this study.To describe the dependence of the conversion on time and temperature, isothermal DSC data were fitted to an autocatalytic model developed by Kamal and extended with a diffusion factor. The results show a very good agreement within the whole conversion range. Also the highly-filled system could be described very well by the phenomenological Kamal model.     

Central European journal of operations research (CJOR) “operations research applied to health services (ORAHS) in Europe: general trends and ORAHS 2020 conference in Vienna,Austria”

Central European Journal of Operations Research - This articles provides a short summary of the research topics and latest research results of the European Working Group “Operations Research...     

Zweifach und dreifach intramolekular verbrückte p‐tert‐Butylcalix[8]aren‐triphosphate – Synthese,Struktur und Stereochemie

Two‐ and Threefold Intramolecular Brigdging p‐tert‐Butylcalix[8]arene Triphosphates – Synthesis, Structure and Stereochemistry [1] The phosphorylation of p‐tert‐butylcalix[8]arene ( 1 ) with phosphorus pentachloride and hydrolysis gives intramolecular bridging tert‐butylcalix[8]arene triphosphates. The reactivity (esterification, dehydratisation, complexation), the structure (nmr and x‐ray), and the stereochemical behaviour of the phosphates will be discussed.