Controllability of the heat equation with an inverse-square potential localized on the boundary

This article is devoted to analyze control properties for the heat equation with singular potential $-\mu/|x|^2$ arising at the boundary of a smooth domain \Omega\subset \rr^N, $N\geq 1$. This problem was firstly studied by Vancostenoble and Zuazua [20] and then generalized by Ervedoza [10]in the context of interior singularity. Roughly speaking, these results showed that for any value of parameters $\mu\leq \mu(N):=(N-2)^2/4$, the corresponding parabolic system can be controlled to zero with the control distributed in any open subset of the domain. The critical value $\mu(N)$ stands for the best constant in the Hardy inequality with interior singularity. When considering the case of boundary singularity a better critical Hardy constant is obtained, namely $\mu_{N}:=N^2/4$. In this article we extend the previous results in [18],[8], to the case of boundary singularity. More precisely, we show that for any $\mu \leq \mu_N$, we can lead the system to zero state using a distributed control in any open subset. We emphasize that our results cannot be obtained straightforwardly from the previous works [20], [10].Comment: 32 page

The role of tension-compression asymmetry of the plastic flow on ductility and damage accumulation of porous polycrystals

The influence of the tension-compression asymmetry of the plastic flow, due to intrinsic single-crystal deformation mechanisms, on porosity evolution and the overall ductility of voided metallic polycrystals is assessed. To this end, detailed micromechanical finite-element analyses of three-dimensional unit cells containing a single initially spherical cavity are carried out. The plastic flow of the matrix (fully-dense material) is described by a criterion that accounts for strength-differential effects induced by deformation twinning of the constituent grains of the metallic polycrystalline materials. The dilatational response of porous polycrystals are calculated for macroscopic axisymmetric tensile loadings corresponding to a fixed value of the stress triaxiality and the two possible values of the Lode parameter. It is shown that damage accumulation, and ultimately ductility of the porous polycrystals are markedly different as compared to the case when the matrix is governed by von Mises criterion. Most importantly, a direct correlation is established between the macroscopic material parameter k that is intimately related to the particularities of the plastic flow of the matrix and the rate of damage accumulation. (C) 2017 Portuguese Society of Materials (SPM). Published by Elsevier Espana, S.L.U.. All rights reserved.The authors gratefully acknowledge the financial support of the Portuguese Foundation for Science and Technology (FCT) via the project PTDC/EMETEC/1805/2012.This work has been supported by FCT (Fundacao para a Ciencia e Tecnologia) in the scope of the project UID/EEA/04436/2013.info:eu-repo/semantics/publishedVersio

Localization of Energy and Momentum in an Asymptotically Reissner-Nordstr\"om Non-singular Black Hole Space-time Geometry

The space-time geometry exterior to a new four-dimensional, spherically symmetric and charged black hole solution that, through a coupling of general relativity with a non-linear electrodynamics, is everywhere non-singular, for small $r$ it behaves as a de Sitter metric, and asymptotically it behaves as the Reissner-Nordstr\"{o}m metric, is considered in order to study the energy-momentum localization. For the calculation of the energy and momentum distributions, the Einstein, Landau-Lifshitz, Weinberg and M\o ller energy-momentum complexes have been applied. The results obtained show that in all prescriptions the energy depends on the mass $M$ of the black hole, the charge $q$, two parameters $$ and $\gamma\in \mathbb{R}^+$, and on the radial coordinate $r$. The calculations performed in each prescription show that all the momenta vanish. Additionally, some limiting and particular cases for $r$ and $q$ are studied, and a possible connection with strong gravitational lensing and micro lensing is attempted.Comment: To appear in Univers

On the energy of a non-singular black hole solution satisfying the weak energy condition

The energy-momentum localization for a new four-dimensional and spherically symmetric, charged black hole solution that through a coupling of general relativity with non-linear electrodynamics is everywhere non-singular while it satisfies the weak energy condition is investigated. The Einstein and M\{o} ller energy-momentum complexes have been employed in order to calculate the energy distribution and the momenta for the aforesaid solution. It is found that the energy distribution depends explicitly on the mass and the charge of the black hole, on two parameters arising from the space-time geometry considered, and on the radial coordinate. Further, in both prescriptions all the momenta vanish.In addition, a comparison of the results obtained by the two energy-momentum complexes is made, whereby some limiting and particular cases are pointed out.Comment: 20 pages, 9 figure

Antibiotic therapy in the treatment of acute otitis media

Department of Otorhinolaryngology, District Hospital of Orhei, the Republic of Moldova, Department of Pharmacology, Dunarea de Jos University of Galati, RomaniaBackground: Acute otitis media is an infection of abrupt onset that usually presents with ear pain. Worldwide acute otitis media affects about 8-11% of people a year. In acute otitis media, antibiotics may speed recovery but may result in side effects. Antibiotics are often recommended in those with severe disease or under two years old. Material and methods: Our study included a retrospective analysis of 117 patients with acute otitis media, whose medical records were examined. The information was analyzed statistically. Results: The results demonstrated an increased involvement of older people and women. The use of antibiotics to treat acute otitis media is determined by Cefazolin in 49-50% cases, Ceftriaxone - 49%, Cefotaxime – 48%, Cefoperazone – 14%, Amoxicillini Clavulanic acid in 16% of cases. Antibiogram was released for 53 patients, and according to it: Cefazolin – 23%, Amoxicilini Clavulanic acid – 15% and the rest were treated with cephalosporin third generation. Conclusions: Depending on severity, the treatment requires the use of antibiotics with broad spectrum. Antibacterial therapy according to antibiogram is contemporary and has the advantage of assessing the appropriate antibiotic

Tratamentul unor sindroame algice de origine neurologică prin metoda de electrostimulare transcraniană (ESTC)

Catedra Anesteziologie şi Reanimatologie Nr.2 USMF “N.Testemițanu”, Congresul II Internaţional al Societăţii Anesteziologie Reanimatologie din Republica Moldova 27-30 august 2009Electrostimularea transcraniană cu aplicarea fronto-occipitală a electrozilor şi utilizarea pachetelor de curenţi impulsiformi cu frecvenţa 77,5 Hz şi valoarea sumară a curentului 4,5 ma, s-a dovedit a fi eficientă în tratamentul bolnavilor suferinzi de migrenă şi nevralgia nervului trigemin după 6-10 proceduri, contribuind şi la ameliorarea parametrilor hemodinamicii intracerebrale şi centrale. Studii aprofundate a savanţilor din ultimile decenii au demonstrat eficacitatea experimentală şi clinică a electrostimulării transcraniene cu curenţi impulsiformi rectangulari, având parametri cu valori critice. Metoda constă în influenţa transcutană, transcraniană a curentului electric impulsiform, care stimulează sistemul antinociceptiv cu actizarea structurilor endorfinice, serotoninergice ale creerului cu dezvoltarea efectelor analgezice, antistresorii, imunomodulatorii etc. Scopul acestui studiu a fost de a evalua eficacitatea metodei ESTC în tratamentul pacienţilor cu migrenă şi nevralgia nervului trigemin, care cu greu se supun tratamentului tradiţonal medicamentos. Cu ajutorul ESTC noi am tratat 25 pacienţi, inclusiv 20 femei şi 5 bărbaţi cu vârsta medie 43±6 ani, cu sindrom algic localizat central şi periferic, având durata medie 9±4 ani, care s-au tratat cu diverse remedii medicamentoase, dar fără rezultate importante. Bolnavi cu migrenă au fost 18, iar cu nevralgia nervului trigemin 7. Pentru ESTC am folosit aparatul DES produs de Î.S.CESID. Pacienţii au primit câte o cură de tratament care includea 7-10 şedinţe cu durata de 30-40 min. fiecare. În cadrul studiului s-a cercetat reoencefalografia, parametrii hemodinamicii şi evoluţia clinică. S-a constatat micşorarea esenţială sau chiar dispariţia durerii din prima şedinţă ESTC. Analgezia apare peste 15-17 min. de la iniţierea procedurii şi durează timp de 3-24 ore. Cu fiecare şedinţă durata efectului analgezic creşte şi ajunge la maximum după 4-5 şedinţe. Trebuie de menţionat că la bolnavii cu migrenă eficacitatea tratamentului se observă de la primele proceduri în proporţie de 85% iar remisia durează 3-7 luni după o cură de tratament. La bolnavii cu nevragia trigeminului efectul apare din prima procedură, iar după 4-6 proceduri durerile dispar definitiv. Hemodinamica intracerebrală şi centrală sa caracterizat prin ameliorare esenţială şi stabilizare. Astfel metoda ESTC s-a dovedit a fi eficientă în tratamentul migrenei şi nevralgiei nervului trigemin în cadrul monoterapiei. Este necesară continuarea aprofundată a studiului

RTVP-1 regulates glioma cell migration and invasion via interaction with N-WASP and hnRNPK

Glioblastoma (GBM) are characterized by increased invasion into the surrounding normal brain tissue. RTVP-1 is highly expressed in GBM and regulates the migration and invasion of glioma cells. To further study RTVP-1 effects we performed a pull-down assay using His-tagged RTVP-1 followed by mass spectrometry and found that RTVP-1 was associated with the actin polymerization regulator, N-WASP. This association was further validated by co-immunoprecipitation and FRET analysis. We found that RTVP-1 increased cell spreading, migration and invasion and these effects were at least partly mediated by N-WASP. Another protein which was found by the pull-down assay to interact with RTVP-1 is hnRNPK. This protein has been recently reported to associate with and to inhibit the effect of N-WASP on cell spreading. hnRNPK decreased cell migration, spreading and invasion in glioma cells. Using co-immunoprecipitation we validated the interactions of hnRNPK with N-WASP and RTVP-1 in glioma cells. In addition, we found that overexpression of RTVP-1 decreased the association of N-WASP and hnRNPK. In summary, we report that RTVP-1 regulates glioma cell spreading, migration and invasion and that these effects are mediated via interaction with N-WASP and by interfering with the inhibitory effect of hnRNPK on the function of this protein