A study of roll attractor and wing rock of delta wings at high angles of attack

Wing rock is a high angle of attack dynamic phenomenon of limited cycle motion predominantly in roll. The wing rock is one of the limitations to combat effectiveness of the fighter aircraft. Roll Attractor is the steady state or equilibrium trim angle (phi(sub trim)) attained by the free-to-roll model, held at some angle of attack, and released form rest at a given initial roll (bank) angle (phi(sub O)). Multiple roll attractors are attained at different trim angles depending on initial roll angle. The test facility (Vigyan's low speed wind tunnel) and experimental work is presented here along with mathematical modelling of roll attractor phenomenon and analysis and comparison of predictions with experimental data

Advances in structure elucidation of small molecules using mass spectrometry

The structural elucidation of small molecules using mass spectrometry plays an important role in modern life sciences and bioanalytical approaches. This review covers different soft and hard ionization techniques and figures of merit for modern mass spectrometers, such as mass resolving power, mass accuracy, isotopic abundance accuracy, accurate mass multiple-stage MS(n) capability, as well as hybrid mass spectrometric and orthogonal chromatographic approaches. The latter part discusses mass spectral data handling strategies, which includes background and noise subtraction, adduct formation and detection, charge state determination, accurate mass measurements, elemental composition determinations, and complex data-dependent setups with ion maps and ion trees. The importance of mass spectral library search algorithms for tandem mass spectra and multiple-stage MS(n) mass spectra as well as mass spectral tree libraries that combine multiple-stage mass spectra are outlined. The successive chapter discusses mass spectral fragmentation pathways, biotransformation reactions and drug metabolism studies, the mass spectral simulation and generation of in silico mass spectra, expert systems for mass spectral interpretation, and the use of computational chemistry to explain gas-phase phenomena. A single chapter discusses data handling for hyphenated approaches including mass spectral deconvolution for clean mass spectra, cheminformatics approaches and structure retention relationships, and retention index predictions for gas and liquid chromatography. The last section reviews the current state of electronic data sharing of mass spectra and discusses the importance of software development for the advancement of structure elucidation of small molecules

Binding of 125I-labelled human alpha interferon to human lymphoid cells

To investigate the binding of interferon to human lymphoid cells, we purified human alpha interferon and radio-labelled it with iodine-125. Binding at 4 degrees C could be saturated and was inhibited by unlabelled interferon; it was specific for cells of human origin. Dissociation constants for the complex of interferon and receptor site were of the order 10(-9)-10(-11) M. All human cells tested showed such binding. Occupation of these high-affinity sites, at 37 degrees C, was compared with the inhibition of cellular growth due to interferon. The most sensitive cell line (Daudi) gave a complete biological response with only a fraction of its sites occupied. Evidence of two sites was found for a line (P3HRI) showing intermediate sensitivity. A relatively insensitive line (Raji) showed no response when all its high-affinity sites were occupied

Interferon enhances the expression of fcgamma receptors.

© 2014, Canadian Center of Science and Education. All rights reserved. In this article the evolution of main conceptions of analyticity is analyzed. Kant’s criteria for analytic/synthetic distinction are discussed. Frege and Carnap notions of analyticity are set out. It is shown that Frege and Carnap shifted the criteria of analyticity to the justificatory status of judgments. The notion of truth in virtue of meaning and its criticism is exposed. Critical arguments against analyticity by W. V. O. Quine are discussed. Williamson’s arguments against traditional notions of analyticity are formulated. Williamson maintains that analytic truths are reduced to truths of other base classes-necessary, semantic or logical. It is shown that the stipulative definition of analyticity is vulnerable to Williamson’s argument. Russell’s conception of truth in virtue of reference determiner is exposed and evaluated. It is defended that the notion of truth in virtue of reference determiner is immune to many standard objections against analyticity