X-Irradiation-Induced Disorganization of Cytoskeletal Filaments and Cell Contacts in HT29 Cells

Organization of cytoskeleton and cell contacts were studied by immunochemistry and electron microscopy in confluent HT29 cultured cells following exposure to 0.5 and 1.0 Gy doses of X-ray. Microtubules were resistant to irradiation, whereas, the actin and intermediate filaments disrupted rapidly following the treatment and their components appeared as clumps of actin and cytokeratin aggregates in the cytoplasm as demonstrated by immunochemistry. Loss of cell contacts and decrease in the number of desmosomes was also characteristic of irradiated cells. Electron microscopy revealed intact desmosomes in control cells and abnormal desmosomes in the irradiated samples characterized by the absence of tonofilaments. The perinuclear filament network and cortical filaments were well detectable by electron microscopy. Under the effect of irradiation, the perinuclear filaments almost disappeared and, at the same time, small bundles of filaments were formed irregularly in the cytoplasm associated with amorphous material

On Gauge Invariance and Spontaneous Symmetry Breaking

We show how the widely used concept of spontaneous symmetry breaking can be explained in causal perturbation theory by introducing a perturbative version of quantum gauge invariance. Perturbative gauge invariance, formulated exclusively by means of asymptotic fields, is discussed for the simple example of Abelian U(1) gauge theory (Abelian Higgs model). Our findings are relevant for the electroweak theory, as pointed out elsewhere.Comment: 13 pages, latex, no figure

Dynamic mineral clouds on HD 189733b : I. 3D RHD with kinetic, non-equilibrium cloud formation

Funding: European community under the FP7 ERC starting grant 257431 (G.L., Ch. H.).Context. Observations of exoplanet atmospheres have revealed the presence of cloud particles in their atmospheres. 3D modelling of cloud formation in atmospheres of extrasolar planets coupled to the atmospheric dynamics has long been a challenge. Aims. We investigate the thermo-hydrodynamic properties of cloud formation processes in the atmospheres of hot Jupiter exoplanets. Methods. We simulate the dynamic atmosphere of HD 189733b with a 3D model that couples 3D radiative-hydrodynamics with a kinetic, microphysical mineral cloud formation module designed for RHD/GCM exoplanet atmosphere simulations. Our simulation includes the feedback effects of cloud advection and settling, gas phase element advection and depletion/replenishment and the radiative effects of cloud opacity. We model the cloud particles as a mix of mineral materials which change in size and composition as they travel through atmospheric thermo-chemical environments. All local cloud properties such as number density, grain size and material composition are time-dependently calculated. Gas phase element depletion as a result of cloud formation is included in the model. In situ effective medium theory and Mie theory is applied to calculate the wavelength dependent opacity of the cloud component. Results. We present a 3D cloud structure of a chemically complex, gaseous atmosphere of the hot Jupiter HD 189733b. Mean cloud particle sizes are typically sub-micron (0.01−0.5 μm) at pressures less than 1 bar with hotter equatorial regions containing the smallest grains. Denser cloud structures occur near terminator regions and deeper (~1 bar) atmospheric layers. Silicate materials such as MgSiO3[s] are found to be abundant at mid-high latitudes, while TiO2[s] and SiO2[s] dominate the equatorial regions. Elements involved in the cloud formation can be depleted by several orders of magnitude. Conclusions. The interplay between radiative-hydrodynamics and cloud kinetics leads to an inhomogeneous, wavelength dependent opacity cloud structure with properties differing in longitude, latitude and depth. This suggests that transit spectroscopy would sample a variety of cloud particles properties (sizes, composition, densities).Publisher PDFPeer reviewe

Respiratory diseases in the »Đuro Đakovic« smelting plant in Slavonski Brod

Uvodno su prikazani uvjeti rada (mikroklima i zaprašenost) u ljevaonici, a zatim su priopćeni rezultati ciljanoga zdravstvenog pregleda 190 radnika izvršenog u 1984. i 1985. godini. Pregled je bio usmjeren na bolesti i oštećenja respiratornog trakta. Najčešće su bile bolesti gornjih dišnih putova (19,4 %) a 12,6 % radnika imalo je kronični bronhitis. Jedan radnik s 25 godina radnog staža u ljevaonici na poslovima čišćenja odljevaka imao je silikozu, u jednog su rendgenološke promjene upućivale na početnu pneumokoniozu, dok je u dvojice nalaz bio suspektan na silikozu. Unatoč bitnom poboljšanju radnih uvjeta i smanjenju zaprašenosti nužni su redoviti pregledi radnika izloženih mineralnoj prašini.Ambient and other working conditions in the smelting plant are described. The results are presented of medical check-up of 190 workers performed in 1984 and 1985 with special emphasis on respiratory diseases. As many as 19.4 % of the examined workers showed affection of the upper respiratory tract, and 12.6 % suffered from chronic bronchitis. One worker with 25 years of work on cast cleaning had apparent silicosis, another showed X-rays findings indicative of silicosis and two workers were found suspect of having the disease. Despite a considerable improvement in working conditions regular medical check-ups of workers exposed to mineral dusts are mandatory

Space of State Vectors in PT Symmetrical Quantum Mechanics

Space of states of PT symmetrical quantum mechanics is examined. Requirement that eigenstates with different eigenvalues must be orthogonal leads to the conclusion that eigenfunctions belong to the space with an indefinite metric. The self consistent expressions for the probability amplitude and average value of operator are suggested. Further specification of space of state vectors yield the superselection rule, redefining notion of the superposition principle. The expression for the probability current density, satisfying equation of continuity and vanishing for the bound state, is proposed.Comment: Revised version, explicit expressions for average values and probability amplitude adde

Pseudo-Hermitian Hamiltonians, indefinite inner product spaces and their symmetries

We extend the definition of generalized parity $P$, charge-conjugation $C$ and time-reversal $T$ operators to nondiagonalizable pseudo-Hermitian Hamiltonians, and we use these generalized operators to describe the full set of symmetries of a pseudo-Hermitian Hamiltonian according to a fourfold classification. In particular we show that $TP$ and $CTP$ are the generators of the antiunitary symmetries; moreover, a necessary and sufficient condition is provided for a pseudo-Hermitian Hamiltonian $H$ to admit a $P$-reflecting symmetry which generates the $P$-pseudounitary and the $P$-pseudoantiunitary symmetries. Finally, a physical example is considered and some hints on the $P$-unitary evolution of a physical system are also given.Comment: 20 page

High-Resolution Image Reconstruction from a Sequence of Rotated and Translated Frames and its Application to an Infrared Imaging System

Some imaging systems employ detector arrays that are not sufficiently dense to meet the Nyquist criterion during image acquisition. This is particularly true for many staring infrared imagers. Thus, the full resolution afforded by the optics is not being realized in such a system. This paper presents a technique for estimating a high-resolution image, with reduced aliasing, from a sequence of undersampled rotated and translationally shifted frames. Such an image sequence can be obtained if an imager is mounted on a moving platform, such as an aircraft. Several approaches to this type of problem have been proposed in the literature. Here we extend some of this previous work. In particular, we define an observation model that incorporates knowledge of the optical system and detector array. The high-resolution image estimate is formed by minimizing a regularized cost function based on the observation model. We show that with the proper choice of a tuning parameter, our algorithm exhibits robustness in the presence of noise. We consider both gradient descent and conjugate-gradient optimization procedures to minimize the cost function. Detailed experimental results are provided to illustrate the performance of the proposed algorithm using digital video from an infrared imager

Low and high beta band activity in the primary sensorimotor cortex is diminished by ipsilateral subthalamic stimulation in Parkinsonian patients [Abstract]

Objective: We analyzed how change of the low and high beta power in the primary sensorimotor cortex relates to different levels of subthalamic stimulation; we hypothesized that it is a suitable biomarker for a closed-loop system. Background: Beta power in the motor system is shown to indicate the kinetic state in Parkinson’s disease. Method: We recruited 20 Parkinsonian patients. Bradykinesia of the most affected hand was measured first with Kinesia motion sensor system (Great Lakes NeuroTechnologies) in medication withdrawal; and four levels of contralateral stimulation (0: OFF, 1-3: decreasing symptoms to ON state) was individually selected. We performed 64-channel electroencephalography (EEG) measurement during a resting state with the four levels of stimulation settings mentioned above. We stimulated the usually used contacts during the whole study, and the ipsilateral stimulation remained ON and unchanged. The 2 minutes long EEG segments were cleaned from DBS artifacts by in-house algorithms. We performed line-noise removal; eye blinks and muscle artifacts were eliminated using ICA analyses. We calculated spectral power at the low (13-20Hz) and high (21-30Hz) beta frequency bands at the sensorimotor cortical region both sides using a beamformer algorithm called the Dynamic Imaging of Coherent Sources. We used repeated measures ANOVA to compare power values in the different locations and stimulation conditions in the two frequency bands. The Medical Research Council in Hungary provided ethical approval. (080958/2015/OTIG). Results: Resting state low- and high-frequency beta power in the primary sensorimotor cortex gradually decreased with the elevation of the ipsilateral stimulation level. In the continuously stimulated contralateral hemisphere, beta power remained at the baseline level. The beta power values measured in the two hemispheres were significantly different in stimulation levels 0-2 but not in level 3 (p < 0.05) both in the low- and high-frequency bands. Conclusion: The change of beta power in the primary sensorimotor cortex during STN-DBS is strictly ipsilateral, and depends on the level of stimulation. Beta power in the sensorimotor cortex could be a potential biomarker for closed-loop DBS. The support of Medtronic Inc. for this project is gratefully acknowledged