99mTc Generator — The Maintenance of High Elution Efficiency

Several protecting procedures were applied to ensure good operating performances of the universal ^99mTc generators based on fission produced ⁹⁹Mo. These procedures include the modifications of the adsorbent. Instead of 1 g of pure Al₂O₃ the adsorption of ⁹⁹Mo is carried out on the multicomponent adsorbent containing the mixture of either Al₂O₃ + SiO₂ or Al₂O₃ · Cu²⁺ + SiO₂. The protection by drying should ensure that the columns contain minimum of moisture during the growth period of ^99mTc. It was found experimentally that the best results are obtained when the ratio of alumina in the mixture was 15 ± 5 (wt.%) and content of copper 365 μg Cu²⁺/column. The comparison of efficiency and applicability of the used protecting procedures is also given.     

Nonlinear Gravitational Waves: Their Form and Effects

A gravitational wave must be nonlinear to be able to transport its own source, that is, energy and momentum. A physical gravitational wave, therefore, cannot be represented by a solution to a linear wave equation. Relying on this property, the second-order solution describing such physical waves is obtained. The effects they produce on free particles are found to consist of nonlinear oscillations along the direction of propagation.     

Structure of large incomplete sets in abelian groups

Let G be a finite abelian group and A be a subset of G. We say that A is complete if every element of G can be represented as a sum of different elements of A. In this paper, we study the following question     

Local bifurcations of synchronization in self-excited and forced unidirectionally coupled micromechanical resonators

A unidirectionally coupled system of Microelectromechanical Systems (MEMS) resonators is investigated. Local bifurcations of both the single resonator and the coupled system are analyzed in the design of the coupled system. We discuss the behavior of the coupled system according to the change in the coupling parameter and the excitation force. Phenomena such as quasiperiodic oscillations and synchronization are shown by numerical simulations and studied analytically through perturbation methods. The coupled system shows oscillatory behavior without the excitation force. In the presence of the excitation force the coupled system exhibits complex behavior which can be beneficial in the design of the coupled system as a sensor.     

Sol–gel encapsulation of acid phosphatase in the presence of the ionic liquid [BMIM][BF4]

Abstract  

The effect of the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF₄]) on acid phosphatase (APase) from wheat germ in solution and in the sol–gel-encapsulated form was investigated to explore new methods of enzyme preparation with improved catalytic performance. APase was encapsulated in hydrogel beads made from tetramethyl orthosilicate. Compared with free APase, 20–28% enzymatic activity was retained in over nine catalytic cycles. Sol–gel encapsulation improved the thermal stability of APase. Heat shock exposure at 60 °C for 1 h resulted in activity decreasing by a factor of three, only, for sol–gel-encapsulated APase, in contrast with a factor of nine decrease for free APase. Addition of 10% v/v [BMIM][BF₄] did result in a slight decrease of enzymatic activity for free and sol–gel-encapsulated APase, but resulted in a remarkable increase in alkaline pH tolerance of sol–gel-encapsulated APase.     

Multi-wall carbon nanotubes (MWCNTs)-doped polypyrrole DNA biosensor for label-free detection of genetically modified organisms by QCM and EIS

In this paper, we describe DNA electrochemical detection for genetically modified organism (GMO) based on multi-wall carbon nanotubes (MWCNTs)-doped polypyrrole (PPy). DNA hybridization is studied by quartz crystal microbalance (QCM) and electrochemical impedance spectroscopy (EIS). An increase in DNA complementary target concentration results in a decrease in the faradic charge transfer resistance (R_ct) and signifying “signal-on” behavior of MWCNTs-PPy-DNA system. QCM and EIS data indicated that the electroanalytical MWCNTs-PPy films were highly sensitive (as low as 4 pM of target can be detected with QCM technique). In principle, this system can be suitable not only for DNA but also for protein biosensor construction.     

Two new sesquiterpenes from Sarcandra glabra

Phytochemical study of the ethanol extract of Sarcandra glabra resulted in the isolation of two new sesquiterpenes, glabranols A (1) and B (2). Their structures were elucidated as 8alpha,9alpha,15-trihydroxylinden-4,7(11)-dien-12,8beta-olide (1) and 1beta,4alpha,7beta,11-tetrahydroxyeudesmane (2), by spectroscopic methods including 1D- and 2D-NMR and FTICR-MS.     

The isomeric ratio of fragment 135Xe from photofission of 233U induced by 23.5 MeV bremsstrahlung

The ratio of the probabilities of population of the isomeric and ground states, so called the isomeric ratio is closely connected to the angular momentum of the initial fission fragments that is dissipated at the later stages of gamma ray cascade. This ratio also provides important information on the nuclear level structure as well as the nuclear reaction mechanism involved. In this work, the isomeric ratio in fission fragment ¹³⁵Xe from photofission of ²³³U induced by 23.5 MeV bremsstrahlung has been determined by the method that uses inert gaseous flow. The results have been discussed and compared with that of other authors.     

The influence of the nature of background anions on the buffer capacity of glycine-containing electrolytes for nickel electroplating

The buffer properties of acetate, sulfate, and chloride glycine-containing electrolytes for nickel electroplating were studied. Various forms of the amino acid and background anions were shown to act in solution as two buffer systems related by competitive complex formation. The buffer capacity of a solution was then the result of the joint action of these systems. The contribution of each of them was determined by its absolute concentration in solution on the one hand and changes in this concentration caused by the addition of H⁺ or OH^? ions on the other.