Homeostatic Modulation of Stimulation-Dependent Plasticity in Human Motor Cortex

Since recently, it is possible, using noninvasive cortical stimulation, such as the protocol of paired associative stimulation (PAS), to induce the plastic changes in the motor cortex, in humans that mimic Hebb's model of learning. Application of TMS conjugated with peripheral electrical stimulation at strictly coherent temporal manner lead to convergence of inputs in the sensory-motor cortex, with the consequent synaptic potentiation or weakening, if applied repetitively. However, when optimal interstimulus interval (ISI) for induction of LTP-like effects is applied as a single pair, Motor evoked potential (MEP) amplitude inhibition is observed, the paradigm known as short-latency afferent inhibition (SLAI). Aiming to resolve this paradox, PAS protocols were applied, with 200 repetitions of TMS pulses paired with median nerve electrical stimulation, at ISI equal to individual latencies of evoked response of somatosensory cortex (N-20) (PASLTP), and at ISI of N-20 shortened for 5 msec (PASLTD) protocols that mimic LTP-like changes in the human motor cortex. MEP amplitudes before, during and after interventions were measured as an indicator based on output signals originating from the motor system. Post-intervention MEP amplitudes following the TMS protocols of PASLTP and PASLTD were facilitated and depressed, respectively, contrary to MEP amplitudes during intervention. During PASLTP MEP amplitudes were significantly decreased in case of PASLTP, while in the case of PASLTD an upward trend was observed. In conclusions, a possible explanation for the seemingly paradoxical effect of PAS can be found in the mechanism of homeostatic modulation of plasticity. Those findings indicate the existence of complex relationships in the development of plasticity induced by stimulation, depending on the level of the previous motor cortex excitability

An overview of generalized entropic forms

The aim of this focus letter is to present a comprehensive classification of the main entropic forms introduced in the last fifty years in the framework of statistical physics and information theory. Most of them can be grouped into three families, characterized by two-deformation parameters, introduced respectively by Sharma, Taneja, and Mittal (entropies of degree $(\alpha,\,\beta$)), by Sharma and Mittal (entropies of order $(\alpha,\,\beta)$), and by Hanel and Thurner (entropies of class $(c,\,d)$). Many entropic forms examined will be characterized systematically by means of important concepts such as their axiomatic foundations {\em \`{a} la} Shannon-Khinchin and the consequent composability rule for statistically independent systems. Other critical aspects related to the Lesche stability of information measures and their consistency with the Shore-Johnson axioms will be briefly discussed on a general ground.Comment: 14 pages, 6 tables, no figures, to appear on EPL: Focus Issues "Progresses on Statistical Physics and Complexity

Revealing the nature of central emission nebulae in the dwarf galaxy NGC 185

In this paper we present new optical observations of the galaxy NGC 185 intended to reveal the status of supernova remnants (SNRs) in this dwarf companion of the Andromeda galaxy. Previously, it was reported that this galaxy hosts one SNR. Our deep photometric study with the 2m telescope at Rozhen National Astronomical Observatory using narrow-band H$\alpha$ and [SII] filters revealed complex structure of the interstellar medium in the center of the galaxy. To confirm the classification and to study the kinematics of the detected nebulae, we carried out spectroscopic observations using the SCORPIO multi-mode spectrograph at the 6m telescope at the Special Astrophysical Observatory of the Russian Academy of Science, both in low- and high-resolution modes. We also searched the archival X-ray and radio data for counterparts of the candidate SNRs identified by our optical observations. Our observations imply the presence of one more SNR, one possible HII region previously cataloged as part of an SNR, and the presence of an additional source of shock ionization in one low-brightness PN. We detected enhanced [SII]/H_alpha and [NII]/H_alpha line ratios, as well as relatively high (up to 90 km s$^{-1}$) expansion velocities of the two observed nebulae, motivating their classification as SNRs (with diameters of 45 pc and 50 pc), confirmed by both photometric and spectral observations. The estimated electron density of emission nebulae is 30 - 200 cm$^{-3}$. Archival XMM-Newton observations indicate the presence of an extended, low-brightness, soft source in projection of one of the optical SNRs, whereas the archival VLA radio image shows weak, unresolved emission in the center of NGC 185.Comment: 15 pages, 14 figures, accepted for publication in A&

Modulacija eksperimentalnog autoimunog encefalomijelitisa (EAE) DA pacova levamizolom

We investigated the influence of an antiparasitic drug, levamisole (2,3,5,6 - tetrahydro - 6- phenyl-imidazo (2,1 - b) thiazole -hydrochloride) with potent immunomodulatory properties on the course and development of experimental autoimmune encepha-lomyelitis (EAE). EAE was induced in female Dark Agouti (DA) rats aged two months by immunization with guinea pig spinal cord in complete Freunds adjuvant. Following immunization animals were subcutaneously treated every other day with 2.2 mg/kg levamisole. The course, development and characteristics of this autoimmune process were monitored as indirect indicators of immune system activity. Our results indicate that in EAE levamisole exerts immunosuppressive effects when administered every other day from the moment of immunization until the end of the disease. This application regime and dose postponed the onset of the first clinical signs, shortened the duration of the disease, abrogated the severity of clinical symptoms and accelerated the recovery of sick animals. In the period of induction and during EAE, levamisole also decreased the severity of changes in the cerebral perivascular spaces. In the peripheral blood of levamisole treated animals with induced EAE, a significant increase of CD4-CD8+ T cells was demonstrated. Furthermore, all rats with induced EAE had decreased numbers of CD4+CD8- T cells in their blood. These changes were in correlation with clinical signs of EAE.U ovom radu su prikazani rezultati ispitivanja anthelmintika levamizola (2,3,5,6 tetrahidro - 6 - fenil - imidazo (2,1 - b) tiazol hidrohlorida) sa snažnim imunomodulatornim svojstvima na tok i razvoj eksperimentalnog autoimunog encefalomijelitisa (EAE). EAE je indukovan imunizacijom ženki pacova soja DA (Dark Agouti) starih dva meseca pomoću homogenata kičmene moždine zamorčeta u kompletnom Freundovom adjuvansu. Posle imunizacije, životinje su tretirane subkutanim injekcijama levamizola (2.2 mg/kg) svaki drugi dan a praćeni su tok, razvoj i karakteristike ovog autoimunog oboljenja kao indirektni indikatori aktivnosti imunološkog sistema. Postignuti rezultati ukazuju dalevamizol ispoljava imunosupresivno delovanje u modelu EAE ako se aplikuje svaki drugi dan od momenta imunizacije do kraja bolesti. Primenjena doza i režim aplikacije odložili su momenat pojavljivanja prvih kliničkih simptoma, skratili trajanje bolesti, ublažili ispoljavanje simptoma i ubrzali oporavak bolesnih životinja. U periodu indukcije i tokom EAE-a levamizol je smanjio stepen promena u cerebralnim perivaskularnim prostorima. U ženskoj krvi ženki pacova sa indukovanim EAE i tretiranim levamizolom uočeno je značajno povećanje broja CD4-CD8+ T ćelija. Osim toga, u obe imunizovane grupe životinja zapaženo je smanjenje broja CD4+CD8- ćelija. Ove promene su bile u skladu sa kliničkom slikom bolesti

Jet Energy Density in Hadron-Hadron Collisions at High Energies

The average particle multiplicity density dN/deta is the dynamical quantity which reflects some regularities of particle production in low-pT range. The quantity is an important ingredient of z-scaling. Experimental results on charged particle density are available for pp, pA and AA collisions while experimental properties of the jet density are still an open question. The goal of this work is to find the variable which will reflect the main features of the jet production in low transverse energy range and play the role of the scale factor for the scaling function psi(z) and variable z in data z-presentation. The appropriate candidate is the variable we called "scaled jet energy density". Scaled jet energy density is the probability to have a jet with defined ET in defined xT and pseudorapidity regions. The PYTHIA6.2 Monte Carlo generator is used for calculation of scaled jet energy density in proton-proton collisions over a high energy range (sqrt s = 200-14000 GeV) and at eta = 0. The properties of the new variable are discussed and sensitivity to "physical scenarios" applied in the standard Monte Carlo generator is noted. The results of scaled jet energy density at LHC energies are presented and compared with predictions based on z-scaling.Comment: 11 pages, LaTeX, 8 figures, Presented at the XVII International Baldin Seminar on High Energy Physics Problems "Relativistic Nuclear Physics & Quantum Chromodynamics", Dubna, Russia, September 27 - October 2, 200

The influence of temperature on mechanical properties of the base material (BM) and welded joint (WJ) made of steel S690QL

This paper presents the analysis of the influence of temperature on mechanic properties of the base material and welded joints made of high strength steel. The joints were welded on S690QL high strength steel plates using the Metal Active Gas (MAG) Welding and two filler materials of different properties. Since the steel S690QL belongs to a group of steels with high strength, the aim of this paper is to determine the temperature at which strength starts to decrease. Experimental tensile testings of the welded joints were performed at five different temperatures in the range from 20 to 550 °C

The influence of temperature on mechanical properties of the base material (BM) and welded joint (WJ) made of steel S690QL

This paper presents the analysis of the influence of temperature on mechanic properties of the base material and welded joints made of high strength steel. The joints were welded on S690QL high strength steel plates using the Metal Active Gas (MAG) Welding and two filler materials of different properties. Since the steel S690QL belongs to a group of steels with high strength, the aim of this paper is to determine the temperature at which strength starts to decrease. Experimental tensile testings of the welded joints were performed at five different temperatures in the range from 20 to 550 °C

A new epigean false scorpion: Roncus sumadijae n. sp. (Neobisiidae, Pseudoscorpiones) from the Balkan Peninsula (Western Serbia)

A new endemic epigean species from the village of Adžina Livada, nr. Kragujevac, Mts. Gledićke Planine, western Serbia, is erected, described and thoroughly illustrated. Its main morphometric characters and important diagnostic features are analyzed and compared to the two closest congeners, Roncus ivanjicae B. Ćurčić, and R. golijae B. Ćurčić from western Serbia, respectively

Rat duodenal motility in vitro: Prokinetic effects of DL-homocysteine thiolactone and modulation of nitric oxide mediated inhibition

Homocysteine is a significant but modifiable risk factor for vascular diseases. As gastrointestinal smooth musculature is similar to blood vessel muscles, we investigated how elevated homocysteine levels affect nitric oxide-mediated neurotransmission in the gut. There is accumulated evidence that a dysfunction of NO neurons in the myenteric plexus may cause various diseases in the gastrointestinal tract such as achalasia, diabetic gastroparesis and infantile hypertrophic pyloric stenosis. In the present study, we aimed to assess the effects of homocysteine on NO-mediated responses in vitro, and to examine the effects of DL-homocysteine thiolactone on the spontaneous motility of rat duodenum and nitrergic neurotransmission. DL-homocysteine thiolactone concentration of 10 μmol/L leads to the immediate increase in tone, amplitude and frequency of spontaneous movements in isolated rat duodenum. L-NAME (30 μmol/L) leads to an increase in basal tone, amplitude and frequency of spontaneous contractions. The relaxations induced by EFS were significantly reduced in duodenal segments incubated in DL-homocysteine thiolactone compared with the control group. EFS-induced relaxations were inhibited by L-NAME in both experimental and control groups. These results suggest that a high level of homocysteine causes an important impairment of non-adrenergic non-cholinergic innervation of the rat duodenum. [Projekat Ministarstva nauke Republike Srbije, br. 175043