Correlated adatom trimer on metal surface: A continuous time quantum Monte Carlo study

The problem of three interacting Kondo impurities is solved within a numerically exact continuous time quantum Monte Carlo scheme. A suppression of the Kondo resonance by interatomic exchange interactions for different cluster geometries is investigated. It is shown that a drastic difference between the Heisenberg and Ising cases appears for antiferromagnetically coupled adatoms. The effects of magnetic frustrations in the adatom trimer are investigated, and possible connections with available experimental data are discussed.Comment: 4 pages, 4 figure

Compatible Poisson-Lie structures on the loop group of SL2SL_{2}

We define a 1-parameter family of $r$-matrices on the loop algebra of $sl_{2}$, defining compatible Poisson structures on the associated loop group, which degenerate into the rational and trigonometric structures, and study the Manin triples associated to them.Comment: 5 pages, amstex, no figure

Endoluminal prolonged endoscopic vacuum-assisted closure therapy in the treatment of patients with perforation of the thoracic segment of the esophagus

Departament Chirurgie №1, Departament Endoscopie, Spitalul Aleksandrovsky, St. Petersburg, Federația Rusă, 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: Perforația esofagului este un eveniment care pune în pericol viața. Tratamentul chirurgical presupune operații de urgență și acestea adesea sunt asociate cu un risc ridicat de complicații postoperatorii. In cazul asocierii mediastinitei mortalitatea este inalta - 40-80%. Principalele cauze ale letalitatii sunt mediastinita, empiemul pleural, complicatile septice. Căutarea unor metode eficiente de corectare a complicațiilor postoperatorii este o problemă stringentă. Material şi metodă: Sub supravegherea noastră în perioada aprilie-mai 2019, au fost trei pacienți cu perforații al segmentului toracic al esofagului.Tuturor pacientilor a fost aplicat tratamentul endoscopic vacuum-asistat (E-VAC). Pentru crearea presiunii negative intraluminale în zona insuficientii suturilor si la nivelul perforării esofagului, a fost utilizată o constructie constând din sonda nasogastrica cu un burete poliuretanic fixat în portiunea distală. Poziționarea acestei construcții în esofag a fost efectuată sub control endoscopic; pacientul a fost supus unei anestezii intravenoase. Nivelul țintă al presiunii negative a fost de 100-150 mmHg. Buretele este înlocuit la fiecare trei-cinci zile. Rezultate: În urma tratamentul endoscopic vacuum-asistat a avut loc inchidera completa a defectului esofagian, manifestările mediastinitei si empiemului pleural au fost cupate. Durata tratamentului spitalicesc a fost în medie 25 de zile. Concluzii: În cazul insuficientei suturilor esofagului operat sau a perforatilor esofagiene, pentruprevenirea patrunderii in mediastin și cavitatea pleurală a sucurilor digestive și a alimentelor; crearea condiților favorabile pentru stimularea proceselor de reparație în zona afectata tratamentul endoscopic vacuum-asistat poate fi recomandată pentru utilizarea pe scară largă.Introduction: Perforation of the esophagus is a life-threatening situation. Surgical treatment demand immediate surgery and is often accompanied by the high risk of the postoperative complications. Mortality, according to different authors, exceeds 80%. The main causes of death are progressive mediastinitis, empyema and sepsis. The searching of effective ways of correcting postoperative complication are a current problem. Material and methods: Under our supervision from April to May 2019, there were three patients with perforations of the thoracic segment of the esophagus. All patients received endoscopic vacuum-assisted treatment (e-vac). For the creation of negative intraluminal pressure at the level of perforation of the esophagus, a construction consisting of nasogastric probe with a polyurethane sponge was used. The positioning of this construction in the esophagus was carried out under endoscopic control; the patient underwent intravenous anesthesia. The target level of negative pressure was 100-150 mmHg. Spongу is replaced every three to five days. Results: Following the endoscopic vacuum-assisted treatment, the complete closure of the esophageal defect took place; the manifestations of mediastinitis and pleural empyema were cupped. The duration of hospital treatment was on average 25 days. Conclusions: in case of insufficiency of the suture of the operated oesophagus or esophageal perforations, for prevention of penetration into the mediastinum and pleural cavity of digestive juices and food, creating favorable conditions for stimulating the repair processes in the affected area, endoscopic vacuum-assisted treatment can be recommended for widespread use

Surface layer structure of AISI 1020 steel at different stages of dry sliding under electric current of high density

Wear intensity of the sliding electric contact steel 1020/steel 1045 depending on sliding time is presented at the contact current density higher than 100 A/cm{2} without lubricant. It is shown that wear intensity of 1020 steel decreases at increasing of sliding time. Wear intensity is stabilized after some sliding time. This time (burn-in time) decreases at reduction of current density. Structural changes are realized in surface layer. Signs of liquid phase are observed on sliding surface. This liquid isn't a result of melting. It is established using Auger spectrometry that the contact layer contains up to 50 at.% of oxygen