Mechanisms of nonlinear spin-wave emission from a microwave driven nanocontact

We present a micromagnetic study of linear and nonlinear spin-wave modes excited in an extended permalloy thin film by a microwave driven nanocontact. We show that the linear mode having the frequency equal to the excitation frequency (f) is driven by the ac Oersted field component perpendicular to the static external field (applied in-plane of the sample). The nonlinear mode with the frequency f /2 is excited as an independent eigenmode within a parametric longitudinal pumping process (due ac Oersted field component parallel to the bias field). Spectral positions of those modes are determined both in the space and phase domain. The results are important for the transfer of information coded into spin-waves between nanocontacts, and for synchronization of spin transfer torque nano-oscillators.Comment: 5 pages, 4 figure

Vasoactive–inotropic score: as a predictor of morbidity in infants after extracorporeal circulation

Catedra de anesteziologie și reanimatologie nr.2, USMF „Nicolae Testemițanu”, Departamentul Reanimare și Terapie Intensivă, Spitalul Clinic Republican, Chișinău, Republica Moldova, Conferința stiințifică „Nicolae Anestiadi – nume etern al chirurgiei basarabene” consacrată centenarului de la nașterea profesorului Nicolae Anestiadi 26 august 2016Introducere. Copiii care suportă intervenții chirurgicale cardiace congenitale cu circulație extracorporeală sunt expuși unui risc ridicat de morbiditate și mortalitate postoperatorie semnificativă. În ciuda faptului că scorul nu a fost încă stabilit ca un predictor al rezultatelor postoperatorii, acest scor a fost ulterior utilizat în cercetarea clinică, ca măsură de severitatea bolii la pacienții care sunt supuși corecției chirurgicale a MCC. Scopul. De a determina asocierea dintre scorul și rezultatul clinic la copii după chirurgia cardiacă. Material și metode. În perioada iunie 2010 decembrie 2015 în unitatea de terapie intensivă au fost admiși 45 pacienți supuși corecției chirurgicale în condiții de circulație extracorporeală a tetralogiei Fallot. Rezultate. Au fost înregistrate toate dozele de preparate ino-vasoactive în primele 24 ore după intervenția chirurgicală și a fost calculat scorul vasoactiv-inotrop. Doar 27% pacienți care au dezvoltat MODS au avut un scor <5p, respectiv 33% au avut un scor <10p, iar 58% un scor <15p și 100% de pacienți care au dezvoltat MODS au avut un scor >15p. De asemenea un scor vasoactiv-inotrop mare a fost asociat cu ședere prelungită în UTI și durata de ventilație mecanică crescută. Concluzii. Intervențiile chirurgicale cardiace congenitale prezic eventuala morbiditate la copiii mici. Utilitatea scorului vasoactiv inotrop ca un predictor independent de dezvoltare a MODS la copii după chirurgia cardiacă poate avea implicații importante pentru cercetări viitoare.Introduction. Children who suffer congenital heart surgery with extracorporeal circulation are at high risk of significant postoperative morbidity and mortality. Despite the fact that the score has not yet been established as a predictor of postoperative outcomes, this score was further used in clinical research as a measure of disease severity in patients undergoing surgical correction of the CHD. Purpose. To determine the association between vasoactive inotropic score and clinical outcome in children after cardiac surgery. Material and methods. Between June 2010 December 2015 in the intensive care unit were admitted 45 patients undergoing surgical correction in conditions of extracorporeal circulation of Fallot's tetralogy. Results. Were registered all doses of vasoactive preparations in the first 24 hours after surgery and was calculated the vasoactive-inotropic score. Only 27% of patients who have developed MODS had a score <5p, and 33% had a score <10p, but 58% of patients had a score <15p and 100% of patients who have developed MODS had a score >15p. Also scoring high inotropic-vasoactive was associated with prolonged ICU stay and duration of mechanical ventilation increased. Also a higher vasoactive inotropic score was associated with prolonged ICU stay and a increased duration of mechanical ventilation. Conclusion. Congenital cardiac surgery with extracorporeal circulation predicts the eventual morbidity in young children. The usefulness of vasoactive inotropic score as an independent predictor of the development of MODS in children after cardiac surgery may have important implications for future research

Магнитно-резонансная томография сердца в оценке аллотрансплантатов, имплантированных в позиции легочной артерии

Centrul de Diagnostic German, Chişinău, Centrul de Chirurgie a Inimii, Spitalul Clinic Republican, ChişinăuTwenty patients with decellularized pulmonary valve allotransplantats in pulmonary position were examined with a 1.5T magnetic resonance imaging unit to assess the diagnostic value of magnetic resonance imaging and clinical performance of the pulmonary allotransplantats replacement. The imaging protocol comprised time-resolved magnetic resonance angiography, axial and short axis cine imaging, for right ventricle functional analysis and phase-contrast velocity encoding imaging, for pulmonary valve and allotransplantats flow evaluation. Time-resolved magnetic resonance angiography yielded diagnostic image data in all examined patients and found normal anatomical and functional information. Axial cine imaging shows right ventricular ejection fraction 51.7 ± 11.7%, median 54.3%. Phase-contrast velocity encoding imaging revealed 7.7 ± 2.6 mm Hg peak pressure gradient, median - 7.1 mm Hg for pulmonary valve allotransplantats and 8.6 ± 4.66 mm Hg peak pressure gradient, median - 8.3 mm Hg, for pulmonary allotransplantats minimal diameter. Regurgitation fraction of pulmonary allotransplantats valve was 14.1 ± 15%, median 14.4%. Magnetic resonance imaging yields clinically relevant information in patients with decellularized pulmonary allotransplantats. Decellularized pulmonary allotransplantats showed good peak pressure gradient and were associated with normal right ventricle function.С целью определения диагностических возможностей метода и оценки морфологического и функционального статуса аллотрансплантатов было обследовано двадцать пациентов с имплантированными аллотрансплантатами в позиции легочной артерии методом магнитно-резонансной томографии. Протокол исследования включил четырехмерную магнитно-резонансную ангиографию, аксиальные срезы cine для функционально-морфологического анализа правого желудочка и фазово-контрастную флоуметрию для изучения гемодинамики аллотрансплантата. Четырехмерная магнитно-резонансная ангиография во всех случаях показала нормальную ангиографическую анатомию и функцию аллотрансплантатов. Фракция выброса правого желудочка при волуметрии cine аксиальных срезов была 51,7 ± 11,7%, медиан 54,3%. Максимальный градиент легочного клапана аллотрансплантатов, рассчитанный методом флоуметрии, был 7,7 ± 2,6 мм рт. ст., медиан 7,1 мм рт. ст. и 8,6 ± 4,66 мм рт. ст., медиан 8,3 мм рт. ст. для минимального диаметра аллотрансплантата. Фракция регургитации легочного клапана аллотрансплантатов составляла 14,1 ± 15,0%, медиан 14,4%. Магнитнорезонансная томография сердца предоставляет клинически исчерпывающую информацию о морфофункциональном состоянии легочных аллотрансплантатов и правого желудочка. Максимальный градиент аллотрансплантатов и систолическая функция правого желудочка у исследуемых пациентов были в пределах нормы, что указывает на удовлетворительное состояние имплантируемых легочных аллотрансплантатов

Direct current control of three magnon scattering processes in spin-valve nanocontacts

We have investigated the generation of spin waves in the free layer of an extended spin-valve structure with a nano-scaled point contact driven by both microwave and direct electric current using Brillouin light scattering microscopy. Simultaneously with the directly excited spin waves, strong nonlinear effects are observed, namely the generation of eigenmodes with integer multiple frequencies (2 \emph{f}, 3 \emph{f}, 4 \emph{f}) and modes with non-integer factors (0.5 \emph{f}, 1.5 \emph{f}) with respect to the excitation frequency \emph{f}. The origin of these nonlinear modes is traced back to three magnon scattering processes. The direct current influence on the generation of the fundamental mode at frequency \emph{f} can be related to the spin-transfer torque, while the efficiency of three-magnon-scattering processes is controlled by the Oersted field as an additional effect of the direct current

Right ventricular outflow tract reconstruction with decellularized human pulmonary valves in congenital heart diseases

Universitatea de Stat de Medicină și Farmacie “Nicolae Testemiţanu”, Spitalul Clinic Republican “Timofei Moşneaga”, Chișinău, Republica Moldova, Al XIII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” și al III-lea Congres al Societății de Endoscopie, Chirurgie miniminvazivă și Ultrasonografie ”V.M.Guțu” din Republica MoldovaIntroducere: Matricea valvulară obţinută prin metodele ingineriei tisulare crează posibilitate de regenerare a ţesutului, un factor important în înlocuirea valvulară la copii. Scopul: Studierea eficacităţii detergenţilor în decelularizarea valvelor pulmonare umane şi a rezultatelor clinice la pacienţii care au suportat implantarea acestor valve. Material şi metode: Au fost prezervate 20 de homogrefe de la donatori cu timpul ischemiei calde cuprins între 2,5 şi 8,5 ore. Pentru decelularizare au fost utilizaţi doi detergenţi pentru 36 ore. În următoarele 96 ore homogrefele au suportat 8 cicluri de spălare în soluţie Ringer cu antibiotice şi antimicotice în condiţii de vibraţie continuă la temperatura de 37 0C. La un termen de 55,8±18,7 luni au fost investigaţi 32 pacienţi la care au fost implantate homogrefele valvulare pulmonare (HVP) decelularizate . Rezultate: În rezultatul preparării HVP cu utilizarea detergenţilor s-a obţinut înlăturarea totală a celulelor de pe matricea valvulară. Semne de degenerare, îngroşarea cuspelor, reducerea mobilităţii lor, dilatarea sau stenozarea valvulară n-a fost depistată în dinamică. Gradientul transvalvular mediu a rămas stabil (4.35±2.54 la 4.66±2.63 mmHg), iar diametrul end-diastolic al ventriculului drept nu s-a schimbat în comparaţiie cu suprafaţa corporală a pacienţilor. Concluzie: Prelucrarea HVP cu detergenţii SDS şi ND a demonstrat înlăturarea totală a celulelor donor de pe homogrefă, cu păstrarea optimală a integrităţii matricei şi membranei bazale. Corecţia chirurgicală a malformaţiilor cardiace congenitale utilizînd HVP decelularizate au arătat un rezultat bun la pacienţii pediatrici cu un potenţial de a se remodela în paralel cu creşterea fiziologică a copilului.Introduction: Non-immunogenic cell-free valvular scaffolds obtained by methods of tissue engineering have provided to induce in/vivo guided tissue regeneration and present a promising valve substitute especially for children. Aim: To investigate the efficacity of detergent treatment in decellularization of HPV tissue and clinical results in patients with implanted cell-free valvular grafts. Material and methods: Twenty PV allografts were harvested from nonbeating heart donors with warm ischemic time from 2,5 to 8,5 hours. Two detergents for 36 hours and eight washing cycles in Ringer solutions with antibiotics during 4 days were used to remove cellular remnants at 370C temperature under continuous shaking conditions. 32 patients with cell-free valvular grafts were investigated mean follow-up 55,8±18,7 months. Results: Treatment of PV with detergents resulted in complete loss of cusps, wall and myocardial cuff cellularity. No signs of pulmonary dilatation or stenosis, valve degeneration, cusps thickness, or reduction of cusp’s mobility were observed during follow-up. Mean transvalvular gradient remained stable (4.35±2.54 to 4.66±2.63 mmHg). End-diastolic diameter of the right ventricle remained unchanged in contrast to physiological increase to BSA of the patients Conclusions: Treatment of the HPVC with ND and SDS solution demonstrated the efficiency in a complete removal of the cells from the human valve tissue with optimal preservation of the scaffold fibres and basal membrane. Surgical correction of congenital heart diseases using “fresh” decellularized PV homografts provides good early postoperative results and has the potential to remodel in parallel with the somatic growth of the child

A passive GHz frequency-division multiplexer/demultiplexer based on anisotropic magnon transport in magnetic nanosheets

The emerging field of magnonics employs spin waves and their quanta, magnons, to implement wave-based computing on the micro- and nanoscale. Multi-frequency magnon networks allow for parallel data processing within single logic elements whereas this is not the case with conventional transistor-based electronic logic. However, a lack of experimentally proven solutions to efficiently combine and separate magnons of different frequencies has impeded the intensive use of this concept. In this Letter, we demonstrate the experimental realization of a spin-wave demultiplexer enabling frequency-dependent separation of GHz signals. The device is based on two-dimensional magnon transport in the form of spin-wave beams in unpatterned magnetic nanosheets. The intrinsic frequency-dependence of the beam direction is exploited to realize a passive functioning obviating an external control and additional power consumption. This approach paves the way to magnonic multiplexing circuits enabling simultaneous information transport and processing.Comment: 16 pages, 3 figure