86 research outputs found
Atomic Scale Fractal Dimensionality in Proteins
The soft condensed matter of biological organisms exhibits atomic motions
whose properties depend strongly on temperature and hydration conditions. Due
to the superposition of rapidly fluctuating alternative motions at both very
low temperatures (quantum effects) and very high temperatures (classical
Brownian motion regime), the dimension of an atomic ``path'' is in reality
different from unity. In the intermediate temperature regime and under
environmental conditions which sustain active biological functions, the fractal
dimension of the sets upon which atoms reside is an open question. Measured
values of the fractal dimension of the sets on which the Hydrogen atoms reside
within the Azurin protein macromolecule are reported. The distribution of
proton positions was measured employing thermal neutron elastic scattering from
Azurin protein targets. As the temperature was raised from low to intermediate
values, a previously known and biologically relevant dynamical transition was
verified for the Azurin protein only under hydrated conditions. The measured
fractal dimension of the geometrical sets on which protons reside in the
biologically relevant temperature regime is given by . The
relationship between fractal dimensionality and biological function is
qualitatively discussed.Comment: ReVTeX4 format with 5 *.eps figure
Charged lepton and neutrino oscillations
Problems long present in the conventional formalism employed for neutrino oscillations are discussed. We here develop a more satisfactory framework based on the Dirac equation and its propagators. When 4-momentum conservation is strictly enforced, there will be induced oscillations in space (but not between generations) for the charged leptons, e.g. and , produced in association with the neutrinos. The oscillations are computed explicitly for the pion decay . Leptonic decays of the are also briefly discussed
Converse Magnetoelectric Experiments on a Room Temperature Spirally Ordered Hexaferrite
Experiments have been performed to measure magnetoelectric properties of room
temperature spirally ordered Sr3Co2Fe24O41 hexaferrite slabs. The measured
properties include the magnetic permeability, the magnetization and the strain
all as a function of the electric field E and the magnetic intensity H. The
material hexaferrite Sr3Co2Fe24O41 exhibits broken symmetries for both time
reversal and parity. The product of the two symmetries remains unbroken. This
is the central feature of these magnetoelectric materials. A simple physical
model is proposed to explain the magnetoelectric effect in these materials.Comment: 6 pages, 5 figure
Viscosity of High Energy Nuclear Fluids
Relativistic high energy heavy ion collision cross sections have been
interpreted in terms of almost ideal liquid droplets of nuclear matter. The
experimental low viscosity of these nuclear fluids have been of considerable
recent quantum chromodynamic interest. The viscosity is here discussed in terms
of the string fragmentation models wherein the temperature dependence of the
nuclear fluid viscosity obeys the Vogel-Fulcher-Tammann law.Comment: 6 pages, ReVTeX 4 format, two figures, *.eps forma
Non-chemical signatures of biological materials: Radio signals from Covid19?
All therapeutic methods dealing with coronavirus (past and present) are based on chemicals. We test for it (positive or negative) chemically and hope to cure it with a future vaccine (some complicated chemical preparation). If and when the virus mutates, another set of chemical protocols for its testing and a hunt for new chemicals as a vaccine shall begin again and again. But the history of modern (western) medicine tells us that our biotechnology is not so limited. Copious scientific evidence for sonic and low energy electromagnetic signals produced by all biological elements (DNA, cells, bacteria, parasites, virus) exists; in turn, the biological elements are affected by these non-chemical signals as well. A careful analysis and a catalogue of the spectrum of these non-chemical signals are proposed here as a unique biophysical signature
Electronic Transport in the Oxygen Deficient Ferromagnetic Semiconducting TiO
TiO films were deposited on (100) Lanthanum aluminates
LaAlO substrates at a very low oxygen chamber pressure
mtorr employing a pulsed laser ablation deposition technique. In previous work,
it was established that the oxygen deficiency in these films induced
ferromagnetism. In this work it is demonstrated that this same oxygen
deficiency also gives rise to semiconductor titanium ion impurity donor energy
levels. Transport resistivity measurements in thin films of TiO
are presented as a function of temperature and magnetic field. Magneto- and
Hall- resistivity is explained in terms of electronic excitations from the
titanium ion donor levels into the conduction band.Comment: RevTeX4, Four pages, Four Figures in ^.eps forma
An All-Atom Model of the Chromatin Fiber Containing Linker Histones Reveals a Versatile Structure Tuned by the Nucleosomal Repeat Length
In the nucleus of eukaryotic cells, histone proteins organize the linear genome into a functional and hierarchical architecture. In this paper, we use the crystal structures of the nucleosome core particle, B-DNA and the globular domain of H5 linker histone to build the first all-atom model of compact chromatin fibers. In this 3D jigsaw puzzle, DNA bending is achieved by solving an inverse kinematics problem. Our model is based on recent electron microscopy measurements of reconstituted fiber dimensions. Strikingly, we find that the chromatin fiber containing linker histones is a polymorphic structure. We show that different fiber conformations are obtained by tuning the linker histone orientation at the nucleosomes entry/exit according to the nucleosomal repeat length. We propose that the observed in vivo quantization of nucleosomal repeat length could reflect nature's ability to use the DNA molecule's helical geometry in order to give chromatin versatile topological and mechanical properties
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