Chernobyl radioactivity on the Black Sea coast of Turkey

After the Chernobyl reactor accident, Eastern Black Sea coast was one of the heavily contaminated regions of Turkey. Clouds loaded with radioactive isotopes arrived the region on May 1986 and emptied their contents with the heavy rains that are frequently seen in the region. In order to asses the current level of contamination, several different samples, moss, lichen, litter, surface soil and soil cores were collected on August 1994. Samples were brought to the laboratory and their moisture, pH and organic matter contents were determined. Gamma-ray spectra of the samples were collected with a HpGe detector. ¹³⁷Cs was the major isotope observed. Activity of most litter samples were below 1000 Bq/kg, while most of the moss samples had activities below 5000 Bq/kg, there were a few with higher ¹³⁷Cs activities. Surface soil samples generally had activities less than 2000 Bq/kg and depth profiles of cesium activities in the soil cores showed regional variations.     

An axially symmetric scalar field and teleparallelism

An axially symmetric scalar field is considered in teleparallel gravity. We calculate, respectively, the tensor, the vector and the axial-vector parts of torsion and energy, momentum and angular momentum in the ASSF. We find the vector parts are in the radial and \(\hat{e}_{\theta}\) directions, the axial-vector, momentum and angular momentum vanish identically, but the energy distribution is different from zero. The vanishing axial-vector part of torsion gives us the result that there occurs no deviation in the spherical symmetry of the spacetime. Consequently, there exists no inertia field with respect to a Dirac particle, and the spin vector of a Dirac particle becomes constant. The result for the energy is the same as obtained by Radinschi. Next, this work also (a) supports the viewpoint of Lessner that the Møller energy-momentum complex is a powerful concept for the energy-momentum, (b) sustains the importance of the energy-momentum definitions in the evaluation of the energy distribution of a given spacetime, and (c) supports the hypothesis by Cooperstock that the energy is confined to the region of non-vanishing energy-momentum tensor of the matter and all non-gravitational fields.     

Synthesis of 1-Aryl-3-phenethylamino-1-propanone hydrochlorides as possible potent cytotoxic agents

1-Aryl-3-phenethylamino-1-propanone hydrochlorides 1-10, which are potentialpotent cytotoxic agents, were synthesized via Mannich reactions using paraformaldehyde,phenethylamine hydrochloride as the amine component and acetophenone, 4'-methyl-, 4'-methoxy-, 4'-chloro-, 4'-fluoro-, 4'-bromo-, 2',4'-dichloro-, 4'-nitro-, 4'-hydroxyacetophenone or 2-acetylthiophene as the ketone component. Yields were in the87-98 % range. Of the compounds synthesized, compounds 2, 6-8 and 10 were new. Theoptimum reaction conditions were investigated by changing the mol ratios of the reactants,the solvents and the acidity levels using 1 and 10 as representative targets. It was observedthat the best mol ratio of the ketone, paraformaldehyde and phenethylamine hydrochloridewas 1:1.2:1 (compared with a 2:2.1 ratio), and the most suitable reaction medium wasethanol containing concentrated hydrochloric acid (compared with only ethanol or nosolvent). This study may serve as a guide for the conditions of the reactions to synthesizecompounds having similar chemical structures.     

Three-dimensional optical profilometry using a four-core optical fibre

This paper describes the use of a four-core optical fibre for measurements of three-dimensional rigid-body shapes. A fringe pattern, which is generated by interference of four wavefronts emitted from the four-core optical fibre, is projected on an object's surface. The deformed fringe pattern containing information of the object's surface topography is captured by a digital CCD camera and is analysed using a two-dimensional Fourier transform profilometry. It is demonstrated for the first time that the use of such a four-core optical fibre increases the compactness and the stability of the fringe projection system.     

Cochlear action potential tuning curves recorded with a derived response technique

Previous action potential (AP) tuning curve methods have used a reduction in amplitude of the probe-elicited AP as an indication of tone-induced masking. The reduction criterion used in different studies has varied from 25% to 100%. For low level probe stimuli, which elicit a low-amplitude AP, this is a sensitive indicator. In contrast, for high-amplitude AP responses elicited by high-level stimuli, the required reduction in absolute terms is large, making it an insensitive indicator. AP tuning curves have been recorded using a sensitive method for detecting masker/probe interaction with a fixed criterion, unrelated to the unmasked AP amplitude. For each masking condition, a derived response was obtained by digitally subtracting the tone-masked AP waveform from the unmasked response. Derived responses are generated if there are ANY changes in the AP waveform induced by the masker, including amplitude changes, latency changes, or even changes in AP morphology not necessarily associated with the major peaks. A fixed criterion (10 microV) of tone-derived (TD) response was used as an indication of interaction of the responses to the masker and probe. Tuning curves generated by this method were compared with those generated by conventional amplitude reduction (AR) methods. TD tuning curves show different characteristics, especially with respect to increasing probe levels. They appear to give a good representation of the array of afferent fibers responding to a probe stimulus. In addition, frequency regions making minor contributions to the AP are better represented in TD tuning curves.     

Efficient on-chip isolation of HIV subtypes

HIV has caused a global pandemic over the last three decades. There is an unmet need to develop point-of-care (POC) viral load diagnostics to initiate and monitor antiretroviral treatment in resource-constrained settings. Particularly, geographical distribution of HIV subtypes poses significant challenges for POC immunoassays. Here, we demonstrated a microfluidic device that can effectively capture various subtypes of HIV particles through anti-gp120 antibodies, which were immobilized on the microchannel surface. We first optimized an antibody immobilization process using fluorescent antibodies, quantum dot staining and AFM studies. The results showed that anti-gp120 antibodies were immobilized on the microchannel surface with an elevated antibody density and uniform antibody orientation using a Protein G-based surface chemistry. Further, RT-qPCR analysis showed that HIV particles of subtypes A, B and C were captured repeatably with high efficiencies of 77.2 ± 13.2%, 82.1 ± 18.8, and 80.9 ± 14.0% from culture supernatant, and 73.2 ± 13.6, 74.4 ± 14.6 and 78.3 ± 13.3% from spiked whole blood at a viral load of 1000 copies per mL, respectively. HIV particles of subtypes A, B and C were captured with high efficiencies of 81.8 ± 9.4%, 72.5 ± 18.7, and 87.8 ± 3.2% from culture supernatant, and 74.6 ± 12.9, 75.5 ± 6.7 and 69.7 ± 9.5% from spiked whole blood at a viral load of 10,000 copies per mL, respectively. The presented immuno-sensing device enables the development of POC on-chip technologies to monitor viral load and guide antiretroviral treatment (ART) in resource-constrained settings.     

Bulk and boundary effects in a one-dimensional water-like fluid

Sites of a one-dimensional lattice may be either vacant or occupied by molecules with two orientational states, a ‘monomer’ state taking up one site and a ‘dimer’ state taking up two sites. There is a nearest-neighbour energy — ε for all molecules and an additional bonding energy — ω for adjacent dimers. Hence low temperatures and pressures favour an open structure with molecules predominantly in the dimer state. Bulk behaviour is investigated by both matrix and combinatorial methods and maxima in density isobars and minima in isothermal compressibility curves are found at certain parameter values. These are anomalous properties similar to those occurring in fluid water.

Boundary effects in a chain with end sites are calculated by matrix methods for several types of boundary condition. The effect on the open structure is measured by the change in the number of dimer-dimer bonds due to the presence of the boundary. For a ‘structure-breaking’ boundary, which forces the adjacent molecule into the monomer state, occupation probabilities near the boundary are compared with bulk values. It is concluded that boundary effects in the fluid are confined to the first few layers of molecules.     

A fibre-optic thermometric sensor based on the thermo-optic effect of titanium dioxide coatings

An experimental determination of the thermo-optic effect of titanium dioxide is described in which the test element is a thin film deposited onto the end face of an optical fibre. The film acts as an etalon. The reflectivity of titanium dioxide films was measured as a function of temperature experimentally over the range 20 °C to 500 °C, and modelled theoretically to yield a value of the thermo-optic coefficient of − 1.49 × 10⁻⁴ K⁻¹. The use of the data in the design of a thin-film optical fibre temperature sensor is described.     

Physical axiomatics: Freudenthal vs. Bunge

The following remarks are intended to show that some of Freudenthal's recent criticisms of Bunge'sFoundations of Physics are wide of the mark. Freudenthal sets his criticisms of detail in a framework of some general considerations of the role played by axiomatic theories in the foundations of physics. In particular, he considers the notion of the objects of an axiomatic theory, the relation of an axiomatic theory to reality, and the notion of the transformation group of a theory. These topics are considered below.     

硫酸盐型盐湖卤水天然制取软钾镁矾

根据我国盐湖的自然气候条件和资源特点,以Na、K、Mg/Cl、SO_4-H_2O五元体系25℃介稳相图为依据,提出了一条经调节卤水组成后,藉盐田天然日晒蒸发获得软钾镁矾的新工艺途径。文中给出了在窒内于模拟野外条件下进行实验的结果。过程中钾的回收率可达80％以上。