Real-time detection of DNA interactions with long-period fiber-grating-based biosensor

Using an optical biosensor based on a dual-peak long-period fiber grating, we have demonstrated the detection of interactions between biomolecules in real time. Silanization of the grating surface was successfully realized for the covalent immobilization of probe DNA, which was subsequently hybridized with the complementary target DNA sequence. It is interesting to note that the DNA biosensor was reusable after being stripped off the hybridized target DNA from the grating surface, demonstrating a function of multiple usability.     

Preparation of α-terpineol and perillyl alcohol using zeolites beta

The preparation of α-terpineol by direct hydration of limonene catalyzed by zeolites beta was studied. The same catalyst was used to prepare perillyl alcohol by isomerization of β-pinene oxide in the presence of water. The aim was to optimize the reaction conditions to achieve high conversions of starting material and high selectivity to the desired products. In the case of limonene, it was found that the highest selectivity to α-terpineol was 88% with conversion of 36% under the conditions: 50 wt% of catalyst beta 25, 10% aqueous acetic acid (10 mL) (volume ratio limonene:H₂O?=?1:4.5), temperature 50 °C, after 24 h. In the case of β-pinene oxide, it was found that the highest selectivity to perillyl alcohol, which was 36% at total conversion, was obtained in the reaction under the following conditions: dimethyl sulfoxide as solvent (volume ratio β-pinene oxide:DMSO?=?1:5), catalyst beta 25 without calcination (15 wt%), demineralized water (molar ratio β-pinene oxide:H₂O?=?1:8), temperature 70 °C, 3 h. The present study shows that the studied reactions are suitable for the selective preparation of chosen compounds.

     

Stimuli‐Responsive Theragrippers for Chemomechanical Controlled Release

We report on a therapeutic approach using thermo‐responsive multi‐fingered drug eluting devices. These therapeutic grippers referred to as theragrippers are shaped using photolithographic patterning and are composed of rigid poly(propylene fumarate) segments and stimuli‐responsive poly(N‐isopropylacrylamide‐co‐acrylic acid) hinges. They close above 32 °C allowing them to spontaneously grip onto tissue when introduced from a cold state into the body. Due to porosity in the grippers, theragrippers could also be loaded with fluorescent dyes and commercial drugs such as mesalamine and doxorubicin, which eluted from the grippers for up to seven days with first order release kinetics. In an in vitro model, theragrippers enhanced delivery of doxorubicin as compared to a control patch. We also released theragrippers into a live pig and visualized release of dye in the stomach. The design of such tissue gripping drug delivery devices offers an effective strategy for sustained release of drugs with immediate applicability in the gastrointestinal tract.     

Determination of mercury species using thermal desorption analysis in AAS

Analytical aspects of the determination of inorganic mercury (Hg) species by thermal desorption followed by atomic absorption spectrometry (AAS) detection were investigated in this work. Characteristic Hg release curves of the following species were observed: Hg⁰, HgCl₂, HgO, HgSO₄, HgS, and the Hg bound to humic acids. Particular attention was dedicated to the thermal stability and change of bond of Hg⁰ in the following matrices: sand, kaolinite, granite, peat, power plant ash, and soil. The bond of elemental Hg in environmental materials was described on basis of this experiment. Contaminated soil samples from two locations in the Czech Republic were investigated by thermal desorption analysis. Afterwards, the contents of volatile and plant-available Hg in the studied samples were determined. The determination of Hg⁰ using the thermal method was related to the results of liquid sequential extraction. The development of Hg speciation and the stability of Hg were assessed on basis of the data obtained. Thus, the analytical procedure used is a suitable tool for the study of inorganic Hg species in contaminated soils.     

Investigation of the Structure of Crystal-Forming Solutions of Potassium Dihydrogen Phosphate K(H2PO4) (KDP type) on the Basis of Modeling Precursor Clusters and According to Small-Angle X-Ray Scattering Data

Crystallography Reports - The potassium dihydrogen phosphate K(H2PO4) (KDP) cluster structures formed in aqueous solutions have been theoretically and experimentally investigated. Cluster modeling...     

Flow injection in-valve-mini-column pretreatment combined with ion chromatography for cadmium, lead and zinc determination

A flow injection (FI) in-valve-mini-column packed with Chelex-100 resin is proposed for on-line sample pretreatment for some metal ions, namely, Cd(II), Pb(II) and Zn(II), prior to simultaneous determination using ion chromatography (IC). A solution containing a mixture of the cations was first passed through the in-valve-mini-column, followed by on-line elution. The eluate was then flowed further to an injection valve and was injected into an ion chromatograph. Conditions of the system were optimized. A single standard calibration was possible. The recoveries of cations were found to be in the range of 95–105%. The developed method was applied to the accurate analysis of zinc ore samples.     

Cyclization of citronellal in a supercritical solvent in a flow reactor in the presence of Al2O3

The reactivity of citronellal under supercritical solvent conditions in a flow reactor in the presence of Al₂O₃ is examined. It is shown that at 160°C, the main transformation product of citronellal is isopulegol, and when the temperature is increased to 190°C, they are monoterpenes with a para-menthane framework and myrcene.     

Sorption of substituted indoles on highly cross-linked polystyrene from water-acetonitrile solutions

The sorption of first synthesized indole derivatives by highly cross-linked polystyrenes from water-acetonitrile solutions was studied by high-performance liquid chromatography. The retention factors and differences in the Gibbs energy of adsorption from infinite diluted solutions were calculated, and the applicability of the Snyder-Soczewinski and Scott-Kucera models for describing the chromatographic retention of sorbates on a polymer network of highly cross-linked polystyrene was shown.