Antibacterial Activity of Dental Composite with Ciprofloxacin Loaded Silver Nanoparticles

Resin composites have been widely used in dental restoration. However, polymerization shrinkage and resultant bacterial microleakage are major limitations that may lead to secondary caries. To overcome this, a new type of antibacterial resin composite containing ciprofloxacin-loaded silver nanoparticles (CIP-AgNPs) were synthesized. The chemical reduction approach successfully produced CIP-AgNPs, as demonstrated by FTIR, zeta potential, scanning electron microscopy, and ultraviolet-visible (UV-vis) spectroscopy. CIP-AgNPs were added to resin composites and the antibacterial activity of the dental composite discs were realized against Enterococcus faecalis, Streptococcus mutans, and the Saliva microcosm. The biocompatibility of modified resin composites was assessed and mechanical testing of modified dental composites was also performed. The results indicated that the antibacterial activity and compressive strength of resin composites containing CIP-AgNPs were enhanced compared to the control group. They were also biocompatible when compared to resin composites containing AgNPs. In short, these results established strong ground application for CIP-AgNP-modified dental composite resins.     

Die klassisch-reguläre Lösbarkeit des Rand-Anfangswertproblems nichtlinearer Wellengleichungen mit einer Randbedingung vom gemischten Typ

Ohne ZusammenfassungFür viele wertvolle Hinweise möchte ich an dieser Stelle meinem akademischen Lehrer, Herrn Prof. Dr. W. von Wahl, danken     

The dielectric properties of liquid-crystal random copolyesters of 4-hydroxybenzoic acid and 2-hydroxy 6-naphthoic acid

Dielectric measurments made from 1 Hz to 10 kHz and from -80 to 150°C on random copolyesters of 4-hydroxybenzoic acid (HBA) and 2-hydroxy 6-naphthoic acid (HNA) reveal three relaxation processes at low frequencies rather than the two seen at audio frequencies. The higher temperature α process is similar to a glass transition, with a high activation energy ～ 170 kcal/mol, but the two lower temperature processes are identified as local mode processes associated with the HNA and HBA moieties, respectively. It is shown that the observed value of the permittivity above the glass transition is lower than that which would be expected for ester groups rotating freely about the local chain axis, and it is suggested that this may be due to several factors including immobilization of dipoles in the crystalline regions, correlated motion of dipoles, and librational rather than rotational motion.     

High speed hydrophilic interaction liquid chromatographic method for simultaneous determination of selected pharmaceuticals in wastewater using a cyano-bonded silica column

In this work, a fast analytical method based on hydrophilic interaction liquid chromatographic-Ultraviolet detection (HILIC-UV) using a short narrow bore cyano-bonded silica column packed with fully porous sub-2?µm particles has been developed for simultaneous determination of eight pharmaceuticals in wastewater. The method involved pre-concentration and clean-up by solid phase extraction using Oasis HLB extraction cartridges. The analytes were separated using a mobile phase consisted of acetonitrile and 5?mM ammonium acetate buffer (95:5?v/v) with a flow rate of 0.6?mL/min. The chromatographic separation was optimized in order to achieve short analysis time and good resolution for all analytes in a single run. Each analyte was detected at its maximum wavelength for higher sensitivity. All analytes could be separated in 5.7?min with resolution ≥2.7. The optimized method was validated based on linearity, precision, detection and quantification limits, selectivity and accuracy. The detection limits of the studied pharmaceuticals ranged from 0.6 to 3?µg/L, while limits of quantification were in the range from 2 to 10?µg/L with UV detection. The developed method is fast, reliable, cost-effective and could be used for the analysis of the studied analytes in other matrices such as food, pharmaceutical preparations and biological fluids.     

Error analysis for rotating active Stokes-Mueller imaging polarimeters

Retrieval of Mueller matrices from intensity measurements is a noise-sensitive process. In addition, the choice of the method used for extracting Mueller matrix elements greatly influences the precision of the final results. Among available procedures, three have been tested and their robustness analyzed by adding Gaussian noise to computer synthesized data and have been verified by comparing experimental data. As expected, the methods based on classical matrix inversion reach their noise reduction limit even if more data are considered. In contrast, the discrete Fourier transform approach features a remarkable stability. The identified reason is that the retrieval process corresponds to filtering with a periodic kernel.     

Effects of thermal fluctuations on non-minimal regular magnetic black hole

We analyze the effects of thermal fluctuations on a regular black hole (RBH) of the non-minimal Einstein–Yang–Mill theory with gauge field of magnetic Wu–Yang type and a cosmological constant. We consider the logarithmic corrected entropy in order to analyze the thermal fluctuations corresponding to non-minimal RBH thermodynamics. In this scenario, we develop various important thermodynamical quantities, such as entropy, pressure, specific heats, Gibb’s free energy and Helmholtz free energy. We investigate the first law of thermodynamics in the presence of logarithmic corrected entropy and non-minimal RBH. We also discuss the stability of this RBH using various frameworks such as the \(\gamma \) factor (the ratio of heat capacities), phase transition, grand canonical ensemble and canonical ensemble. It is observed that the non-minimal RBH becomes globally and locally more stable if we increase the value of the cosmological constant.     

Impact of generalized dissipative coefficient on warm inflationary dynamics in the light of latest Planck data

The warm inflation scenario in view of the modified Chaplygin gas is studied. We consider the inflationary expansion to be driven by a standard scalar field whose decay ratio \(\Gamma \) has a generic power-law dependence with the scalar field \(\phi \) and the temperature of the thermal bath T. By assuming an exponential power-law dependence in the cosmic time for the scale factor a(t), corresponding to the intermediate inflation model, we solve the background and perturbative dynamics considering our model to evolve according to (1) weak dissipative regime and (2) strong dissipative regime. Specifically, we find explicit expressions for the dissipative coefficient, scalar potential, and the relevant inflationary observables like the scalar power spectrum, scalar spectral index, and tensor-to-scalar ratio. The free parameters characterizing our model are constrained by considering the essential condition for warm inflation, the conditions for the model evolves according to weak or strong dissipative regime, and the 2015 Planck results through the \(n_s\)–r plane.     

Two Novel Lyso-Ornithine Lipids Isolated from an Arctic Marine Lacinutrix sp. Bacterium

The Lacinutrix genus was discovered in 2005 and includes 12 Gram-negative bacterial species. To the best of our knowledge, the secondary metabolite production potential of this genus has not been explored before, and examination of Lacinutrix species may reveal novel chemistry. As part of a screening project of Arctic marine bacteria, the Lacinutrix sp. strain M09B143 was cultivated, extracted, fractionated and tested for antibacterial and cytotoxic activities. One fraction had antibacterial activity and was subjected to mass spectrometry analysis, which revealed two compounds with elemental composition that did not match any known compounds in databases. This resulted in the identification and isolation of two novel isobranched lyso-ornithine lipids, whose structures were elucidated by mass spectrometry and NMR spectroscopy. Lyso-ornithine lipids consist of a 3-hydroxy fatty acid linked to the alpha amino group of an ornithine amino acid through an amide bond. The fatty acid chains were determined to be iso-C15:0 (1) and iso-C16:0 (2). Compound 1 was active against the Gram-positive S. agalactiae, while 2 showed cytotoxic activity against A2058 human melanoma cells.     

Overlap of Doxycycline Fluorescence with that of the Redox-Sensitive Intracellular Reporter roGFP

Tetracycline-inducible systems allow for either suppression or induction of transgene expression to facilitate studies of cell physiology. Doxycycline is a preferred inducer for these gene expression systems due to its membrane permeability; however, the heterocyclic structure of doxycycline exhibits fluorogenic properties that can potentially bias measurement of other fluorochromes. Thus the simultaneous use of tetracycline-inducible systems and fluorescent proteins as reporter genes or as intracellular biosensors may lead to potentially confounding results. Herein, using cells which co-express the ratiometric redox sensitive intracellular reporter, roGFP, and a tetracycline-inducible reporter plasmid encoding the reporter gene, mCherry, as a model system, we describe the overlapping intracellular fluorescent signals between doxycycline and commonly used intracellular fluorescent probes. In our cells, the addition of doxycycline to cells caused a dose- and time-dependent increase in cell fluorescence with 405 nm excitation which overlapped with that of the oxidized configuration of roGFP. Incubating cells in concentrations of doxycycline less than 1 μg/mL and removing doxycycline from the media 60 min before performing experiments eliminated fluorescence interference while still maintaining maximal reporter transgene activation.     

Studies of the Rate Constant of l-DOPA Oxidation and Decarboxylation by HPLC

The objective of current investigation was to study the degradation behavior of l-DOPA under different conditions by high performance liquid chromatography (HPLC), and to develop and validate a stability-indicating HPLC method. The developed RP-HPLC method was validated with respect to linearity, accuracy, precision and specificity. Oxidation was found to occur in alkaline and to some extent in thermal conditions, while the drug was stable when incubated at acidic conditions and under photolytic stress. The oxidation of l-DOPA was observed to follow first-order kinetics. The degradation rate constants and half-life were calculated. The cytotoxicity and enzymatic degradation of l-DOPA was examined using the human intestinal epithelial Caco-2 cells. The drug was rapidly decarboxylated by aromatic amino acid decarboxylase to dopamine. The conversion of l-DOPA to dopamine was dose- and time-dependent.