Influence of Inert Particle Additives on Properties of Nano-Microcrystalline Alloys on Based on Al–Fе–V–Si

Metallurgist - A new trend in production of aluminum alloys used in construction in the automotive and aerospace industries is manufacture of composite materials. The structure and connection...     

Structural and spectroscopic studies of mechanochemically activated nanosized apatite from Syria

Phosphorite sample from Syria is subjected to mechanochemical treatment in planetary mill equipped with 20 mm steel milling bodies. A complex of chemical and physical methods was applied, namely chemical analysis, powder XRD, IR spectroscopy, and SEM in order to prove changes in the structure of the minerals in the modified samples. These changes are manifested mainly in transformations of a considerable part of apatite into a nanosized phase, breakage of the coordination complex CaO₆F, and localization of OH⁻ groups in the position of F⁻ and CO₃²⁻ in the position of PO₄³⁻ of the apatite structure. As a result of these transformations the assimilable content of in the activated samples is increased and this gives opportunity to suppose that the activated phosphorite could be used as a phosphorous fertilizer.     

Interaction of DNA-dependent protein kinase with DNA and with Ku: biochemical and atomic-force microscopy studies

DNA-dependent protein kinase (DNA-PK or the scid factor) and Ku are critical for DNA end-joining in V(D)J recombination and in general non-homologous double-strand break repair. One model for the function of DNA-PK is that it forms a complex with Ku70/86, and this complex then binds to DNA ends, with Ku serving as the DNA-binding subunit. We find that DNA-PK can itself bind to linear DNA fragments ranging in size from 18 to 841 bp double-stranded (ds) DNA, as indicated by: (i) mobility shifts; (ii) crosslinking between the DNA and DNA-PK; and (iii) atomic-force microscopy. Binding of the 18 bp ds DNA to DNA-PK activates it for phosphorylation of protein targets, and this level of activation is not increased by addition of purified Ku70/86. Ku can stimulate DNA-PK activity beyond this level only when the DNA fragments are long enough for the independent binding to the DNA of both DNA-PK and Ku. Atomic-force microscopy indicates that under such conditions, the DNA-PK binds at the DNA termini, and Ku70/86 assumes a position along the ds DNA that is adjacent to the DNA-PK.     

Web users with autism: eye tracking evidence for differences

Anecdotal evidence suggests that people with autism may have different processing strategies when accessing the web. However, limited empirical evidence is available to support this. This paper presents an eye tracking study with 18 participants with high-functioning autism and 18 neurotypical participants to investigate the similarities and differences between these two groups in terms of how they search for information within web pages. According to our analysis, people with autism are likely to be less successful in completing their searching tasks. They also have a tendency to look at more elements on web pages and make more transitions between the elements in comparison to neurotypical people. In addition, they tend to make shorter but more frequent fixations on elements which are not directly related to a given search task. Therefore, this paper presents the first empirical study to investigate how people with autism differ from neurotypical people when they search for information within web pages based on an in-depth statistical analysis of their gaze patterns.     

Interaction of histone H1 with cis-platinum modified DNA

Cis-diamminedichloroplatinum(II) (cis-DDP) is known as an effective anticancer drug. Its therapeutic effect is supposed to be a consequence of the covalent binding to DNA. A number of cellular proteins were found to bind selectively to DNA modified by cis-DDP (but not by its isomer trans-DDP). Here we present our observations on interaction of the linker histone H1 with cis- and trans-DDP modified DNA fragments. The results afford new experimental information about the preferential binding of histone H1 to cis-DDP-distorted DNAs versus trans-DDP modified ones.     

Analyses and assessment of the spatial and temporal distribution of nitrogen compounds in surface waters

The temporal concentration variations and spatial distribution of nitrogen compounds (nitrate, nitrite, ammonium) in the natural surface waters of Stara Zagora Region, Bulgaria, over a period of 1 year were assessed in the present study. Nitrate‐nitrogen concentrations in all surface water samples, except for the December value – 21.8 mg/L in Zetyovo Reservoir, were within the permissible national quality standards. NO₂ ^–‐N could be classified as a priority pollutant of Chirpan and Zetyovo Reservoirs waters. The greatest extent of NH ₄ ⁺‐N pollution was registered in Chirpan Reservoir surface waters. The correlation study revealed appreciable mutual relationship only between NH₄ ⁺‐N and NO ₂ ^–‐N in the surface waters. The hierarchical cluster analysis (HCA) exhibited divergent apportionment of nitrogen compounds in the surface water bodies.     

Measuring the235U α values at a thermal point

Translated from Atomnaya Énergiya, Vol. 65, No. 6, pp. 434–435, December, 1988.     

“Keep it simple!”: an eye-tracking study for exploring complexity and distinguishability of web pages for people with autism

Universal Access in the Information Society - A major limitation of the international well-known standard web accessibility guidelines for people with cognitive disabilities is that they have not...