1,982 research outputs found

    Synthesis of polyamides from diamines of the fluorene series

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    Aromatic polyamides were prepared by polycondensation of isophthaloyl chloride and 2,7-diaminofluorene, 2,7-dimainofluorenone, or 2,5-diaminofluorenone in AcNMe2 or N-methyl-2-pyrrolidinone at 20 deg - 30 deg for 1.5-2 hr. Isophthaloyl chloride-2,5-diaminofluorenone copolymer 39609-29-51 was sol. in AcNMe2, N-methyl-2-pyrrolidinone, DMF, and hexamethylphosphoramide, whereas isophthaloyl chloride-2,7-diamino-fluorene copolymer 39609-30-3 and isophthaloyl chloride-2,7-diamino-fluorenone copolymer 39609-31-0 were not sol. in the solvents cited. The aromatic polyamides revealed thixotropic properties in 0.5% solutions in H2SO4

    STUDY OF STRESSED-DEFORMED STATE OF THE POLYGONAL ARCH COVERINGS OF WOOD

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    In this work the use of wooden I-beams with OSB wall as the load bearing elements for polygonal arch coverings of buildings of various spans are considered. Special steel connecting pieces can shape the polygonal arch coverings. Calculations of the constructions with a span of 12 and 18 meters and an analysis of their stress-strain state are given.In this work the use of wooden I-beams with OSB wall as the load bearing elements for polygonal arch coverings of buildings of various spans are considered. Special steel connecting pieces can shape the polygonal arch coverings. Calculations of the constructions with a span of 12 and 18 meters and an analysis of their stress-strain state are given

    Quasi-One-Dimensional Quantum Ferrimagnets

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    We present an exact diagonalization study of the half-filled Hubbard model on bipartite quasi-one-dimensional lattices. In particular, we emphasize the dependence of the ferrimagnetic ground state properties, and its associated magnetic excitations, on the Coulomb repulsion U.Comment: 6 pages, 12 figures, to be published in Physica A: special issue in honor of Prof. Bernard Sapova

    Surgical treatment of biliary ducts confluence cholangiocarcinoma

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    Institutul Național de Chirurgie și Transplantologie “А.Shalimov”, Kiev, Ucraina, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Introducere: Tratamentul chirurgical al colangiocarcinomului parahilar rămîne a fi una dintre cele mai complicate și nerezolvate probleme a chirurgiei hepatice contemporane. În pofida succesului semnificativ privind diagnosticul, implementarea tehnologiilor inovative în pregătirea preoperatorie, aplicarea tehnicilor actuale de transecție a parenchimului și transplant hepatic – rezultatele tratamentului chirurgical rămîn nesatisfăcătoare. O dificultate deosebită o prezintă cazurile de invazie tumorală a venei porte și a arterei hepatice. Scopul: Studierea rezultatelor tratamentului chirurgical la pacienții cu tumora Klatskin și invazie tumorală în vasele magistrale. Material și metode: În perioada anilor 2002-2015 în secția de Chirurgie și transplant hepatic au fost efectuate rezecții hepatice extinse la 160 pacienți cu tumori ale confluenței ducturilor biliare hepatice. Rezultate: Vîrsta medie a pacienților a constituit 60±12 ani. Pentru aprecierea caracterului implicării tumorale a arborelui biliar s-a utilizat clasificarea anatomică a colangiocarcinomului hilar după Bismuth–Corlette. În toate cazurile, preoperator era efectuată decompresia biliară prin drenare transparieto-transhepatică sau stentarea căilor biliare. Ca criteriu de apreciere a decompresiei biliare adecvate a fost scăderea valorii bilirubinei <50μmol/l și absența tabloului clinic de colangită. În 86 cazuri sa efectuat rezecția venei porte cu reconstrucția ulterioară a acesteia, în 7 cazuri – hepatoduodenal-ligamentectomia cu rezecția unimomentană și reconstrucția venei porte și a arterei hepatice. În 1 caz a fost efectuată hepatectomia stîngă cu lobectomie caudată totală în asociere cu hepatoduodenal-ligamentectomie și arterializarea fluxului portal. În 4 cazuri rezecția hepatică a fost suplinită cu rezecția pancreatoduodenală. Rata supraviețuirii la 1, 3 și 5 ani în cazul pacienților cu rezecție a venei porte a fost 77,8%, 66,7% și 39%, respectiv. Concluzii: Tactica chirurgicală agresivă în tratamentul pacienților cu tumori Klatskin oferă un caracter radical maxim, permite creșterea rezecabilității tumorilor cu invazia venei porte și arterei hepatice cu o rată acceptabilă a mortalității și supraviețuirii la distanță.Introduction: Surgical treatment of perihilar cholangiocarcinoma is one of the most complicated and not finally solved problems of contemporary hepatic surgery. Despite of significant progress in diagnostics, the implementation of innovative technologies for preoperative prepare, contemporary methods of parenchimal dissection and liver transplantation, the results of surgical treatment remain unsatisfactory. Especial difficulties represent the cases with tumor invasion of portal vein and hepatic artery. Aim: the current study surveys the results of surgical treatment of patients with Klatskin tumor with major vessels invasion. Material and methods: Between 2002 – 2015 in the Transplantology and Liver Surgery Unit were performed large liver resections of 160 patients with malignant tumors of biliary ducts confluence.Results: Mean age was 60±12 years. Description of biliary tree injury was done according to Bismuth–Corlette anatomical classification of hilar cholangiocarcinoma. In all cases patients undergone preoperative decompression of biliary ducts by mean of transcutaneous transhepatic drainage or biliary stenting. The criterion of adequate biliary decompression served decreasing serum bilirubin level under 50 mcmol/l, and the absence of segmentary colangitis clinical signs. From 160 patients, in 86 cases portal vein resection with following reconstruction has been performed. In 7 patients hepatoduodenoligamentectomy was performed, with simultaneous resection and reconstruction of the portal vein and hepatic artery. In one case left-sided hemihepatectomy with total caudate lobectomy associated with hepaticoduodenoligamentectomy and arterialization of portal axis hase been done. In 4 cases liver resection was completed with pancreatduodenectomy. 1, 3 and 5-years survival in the portal vein resection group constituted 77,8%, 66,7% and 39%, respectively. Conclusions: Aggressive tactics of biliary ducts confluence surgical treatment ensure maximal radicalism, provide increase of resecability in portal vein and hepatic artery tumor invasion, with acceptable lethality and distant survival rate

    Statistical shape modeling of multi-organ anatomies with shared boundaries

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    Introduction: Statistical shape modeling (SSM) is a valuable and powerful tool to generate a detailed representation of complex anatomy that enables quantitative analysis of shapes and their variations. SSM applies mathematics, statistics, and computing to parse the shape into some quantitative representation (such as correspondence points or landmarks) which can be used to study the covariance patterns of the shapes and answer various questions about the anatomical variations across the population. Complex anatomical structures have many diverse parts with varying interactions or intricate architecture. For example, the heart is a four-chambered organ with several shared boundaries between chambers. Subtle shape changes within the shared boundaries of the heart can indicate potential pathologic changes such as right ventricular overload. Early detection and robust quantification could provide insight into ideal treatment techniques and intervention timing. However, existing SSM methods do not explicitly handle shared boundaries which aid in a better understanding of the anatomy of interest. If shared boundaries are not explicitly modeled, it restricts the capability of the shape model to identify the pathological shape changes occurring at the shared boundary. Hence, this paper presents a general and flexible data-driven approach for building statistical shape models of multi-organ anatomies with shared boundaries that explicitly model contact surfaces.Methods: This work focuses on particle-based shape modeling (PSM), a state-of-art SSM approach for building shape models by optimizing the position of correspondence particles. The proposed PSM strategy for handling shared boundaries entails (a) detecting and extracting the shared boundary surface and contour (outline of the surface mesh/isoline) of the meshes of the two organs, (b) followed by a formulation for a correspondence-based optimization algorithm to build a multi-organ anatomy statistical shape model that captures morphological and alignment changes of individual organs and their shared boundary surfaces throughout the population.Results: We demonstrate the shared boundary pipeline using a toy dataset of parameterized shapes and a clinical dataset of the biventricular heart models. The shared boundary model for the cardiac biventricular data achieves consistent parameterization of the shared surface (interventricular septum) and identifies the curvature of the interventricular septum as pathological shape differences

    Hepatic veins reconstruction in right lobe liver transplantation from living related donor

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    Institutul Național de Chirurgie și Transplantologie “А.Shalimov”, Kiev, Ucraina, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Introducere: Lobul hepatic drept (LHD) reprezintă cea mai frecvent utilizată grefă de transplant alogen la adulți. Prelevarea acestuia fără vena hepatică medie (VHM) poate fi însoțită de congestia segmentelor V și VIII și de sindromul masei mici de transplant la recipient, în timp ce prelevarea cu VHM se poate complica cu sindromul de ficat restant mic și insuficiență hep atică postoperatorie (IHP) la donator. O opțiune ar fi reconstrucția venelor hepatice ale segmentelor V și VIII și prelevarea grefei fără VHM. Scopul lucrării: Studierea rezultatelor diferitor tehnici de reconstrucție a fluxului venos hepatic în cazul transplantului alogen de LHD de la donator viu. Material și metode: Au fost studiate 73 transplanturi alogene de LHD de la donator viu. În 33 cazuri ca grefă de transplant a servit LHD prelevat cu VHM, plastia căreia a fost efectuată cu petic din vena portă a recipientului (tehnica „bumerang”). În 40 cazuri s-a prelevat LHD fără VHM, din care în 4 cazuri reconstrucția fluxului venos de la segmentele hepatice V și VIII s-a efectuat cu ajutorul unui petic sintetic sau autovenă. Prelevarea LHD cu VHM s-a efectuat doar în cazurile prenzenței venei hepatice segmentare IVb bine definite anatomo-radiologic. Vena hepatică dreaptă infero-posterioară a fost reconstruită doar avînd diametrul mai mare de 5 mm. Rezultate: IHP s-a dezvoltat la 5 (15,5%) recipienți în grupa cu VHM și la 16 (40%) recipienți fără VHM (p=0,03). Volumul hemoragiei (1230±20 ml și 1110±35 ml), durata intervenției (612±22 min și 560±39 min), timpul total al ischemiei (86±13 min și 72±14 min) între ambele grupuri nu au fost semnificativ diferite (p>0,05). Deasemenea nu s-au deosebit și complicațiile vasculare: 3 (9%) și 5 (12,5%), respectiv. În grupul cu VHM mortalitatea la 60 zile în cazul recipienților a fost 12,1% (4 cazuri) vs 15% (6 cazuri) în grupul fără VHM. IHP s-a dezvoltat la donatori în 4 (12,1%) cazuri în grupul cu VHM și în 4 (10%) cazuri în grupul fără VHM. Toți donatorii au fost externați la a 7-14-a zi. Rata complicațiilor infecțioase și biliare în ambele grupuri nu s-a deosebit. Concluzii: Prelevarea LHD cu VHM poate fi efectuată în siguranță în cazul prezenței la donator a venei segmentare IVb bine definite. Utilizarea transplantului LHD cu VHM permite scăderea semnificativă a ratei IHP la recipienți. În prezența unor vene afluente segmentare V și VIII de calibru mare în cazul prelevării LHD fără VHM este necesară reconstrucția acestora cu petic autovenos sau sintetic.Introduction: Right hepatic lobe (RHL) is the most commonly used graft for allogenic transplant in adults. Its collecting without middle hepatic vein (MHV) may be accompanied by congestion of V and VIII segments and by syndrome of small-mass transplant at recipients, while the collecting with VHM may be complicated by small remaining-liver syndrome and postoperative liver failure (PLF) at donors. One option would be the reconstruction of hepatic vein of segments V and VIII and taking graft without VHM. The aim: To study the results of different hepatic veins reconstruction techniques in right lobe liver transplantation from living related donor. Material and methods: We studied the results of 73 RHL transplants from a living related donor. In 33 cases, the RHL graft was used with MHV, its reconstruction being performed using auto-venous portal patch from recipient (the "boomerang" technique). In another 40 cases, the RHL graft was used without the MHV. Of these, in 4 cases was performed a reconstruction of V and VIII segmental veins using prosthesis or auto-venous patch. The collecting of RHL graft with MHV was performed only in the presence of well-defined radiographically and anatomically 4b sub-segmental vein. The right infero-posterior hepatic vein reconstruction was performed at a diameter greater than 5 mm. Results: PLF was revealed at 5 (15.5%) recipients with MHV and 16 (40%) recipients without MHV (p=0.03). The volume of bleeding (1230±20 ml and 1110±35 ml), the operating time (612±22 min and 560±39 min), total time of ischemia (86±13 min and 72±14 min) in both groups was not significant different (p>0.05). Also, the vascular complications were no special different 3 (9%) and 5 (12.5%), respectively. In the group with MHV the mortality at 60 days for recipients was 12.1% (4 cases) vs 15% (6 cases) in the group without MHV. PLF has been developed at 4 (12.1%) donors in group with MHV and 4 (10%) donors without VHM. All donors were discharged in 7-14 days. The rate of infectious and biliar complications in both groups was not different. Conclusions: The RHL graft collecting with MHV can be performed safely only in the presence of well-defined 4b subsegmental vein. The using of RHL transplant with MHV allows a significant decrease of PLF rate at recipients. If you have a large segmental venous tributaries from V and VIII segments in RHL graft collecting without MHV, it needs their reconstruction using prosthesis or auto-venous patch

    15-years experience of living donor liver transplantation in Ukraine

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    Institutul Național de Chirurgie și Transplantologie “А.Shalimov”, Kiev, Ucraina, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Introducere: Transplantul hepatic (TH) reprezintă unica opțiune de tratament radical în cazul patologiilor hepatice terminale. Din 2001 Institutul de Chirurgie și Transplantologie din Ucraina a realizat programul de TH de la donator viu. Scopul lucrării: Evaluarea rezultatelor TH pe perioada anilor 2001-2015. Material și metode: Au fost studiate rezultatele a 142 TH alogene de la donator viu, efectuate pe perioada anilor 2001-2015. Toți recipienții s-au aflat pe lista de așteptare în baza criteriilor UNOS. Indicațiile au fost: ciroza secundară diferitelor maladii (hepatita virală – 23,2%, hepatita autoimună – 9,15%, alte etiologii – 11,3%), ciroza criptogenă – 13,4%, atrezia biliară – 31,7% și tumorile hepatice – 11,3%. Investigarea donatorului a fost efectuată în conformitate cu protocolul prestabilit. Volumul grefei de transplant a fost calculat în baza datelor CT și RMN. Rezultate: Din 142 TH de la un donator viu în 73 cazuri s-a transplantat lobul hepatic drept, 14 – lobul stîng și 54 – secțiunea laterală stângă. Într-un caz, a fost realizat transplantul unimomentan de la 2 donatori vii. Vârsta medie a recipienților a fost – 22,3±8,2 ani (7 luni – 58 ani), 75 dintre aceștia au fost de sex masculin. Toți recipienții au prezentat ciroză decompensată clasa C după Child-Pugh. Valoarea medie a stării funcționale integrale hepatice a fost de 12,5±1,2 puncte. Ascita refractară preoperator a fost observată la 47 pacienți, 8 pacienți au prezentat episoade recurente de peritonită bacteriană spontană, 6 pacienți – sindrom hepatorenal de tip II. Pierderea de sînge intraoperator a fost 2400±900 ml, durata operației – 16±3 ore. Durata ischemiei la rece: 45±17 min, la cald – 48±12 min. Durata medie a spitalizării recipienților a constituit – 32±8 zile. Mortalitatea postoperatorie precoce a fost în 23 cazuri – 16,1%. Rata de supraviețuire la 1 an – 73,9% și la 5 ani – 66,9%. Concluzii: TH alogen de la donator viu reduce semnificativ timpul de aflare a recipientului în lista de așteptare și îmbunătățește supraviețuirea. Rezultatele TH sunt comparabile cu rezultatele studiilor străine, ceea ce face posibilă recomandarea efectuării pe larg a TH, ca metodă de tratament radical a pacienților cu patologii hepatice terminale.Introduction: Liver transplantation is the only radical treatment method of terminal liver diseases. From 2001, Institute of Surgery and Transplantology of Ukraine has been performing allogenic transplantation program from the living donor. Aim: the current study is oriented on the survey of transplantation results for 2001-2015. Material and methods: The study surveyed 142 patients’ transplantations from living donors, performed from 2001 to 2015. All recipients were on the waiting list for transplantation from a relative, according to UNOS Criteria. The indications for inclusion in the waiting-list were: liver cirrhosis as a consequence of different diseases (viral hepatitis – 23.2%; autoimmune hepatitis – 9.15%, other etiology – 11.3%), cryptogenic cirrhosis – 13.4%, biliary atresia – 31.7% and liver cirrhosis – 11.3%. Donor investigations have been done according to the created protocol. Transplant’s volume was calculated with CT and MRI. Results: From 142 patients who supported living donor transplantation, in 73 cases has been performed right hemi-liver transplantation, in 14 – of the left hemi-liver, and in 54 – of the left lateral section. In one case has been performed simultaneous transplantation from 2 living donors. The average recipient’s age was 22.3±8.2 years (7 months – 58 years), 75 recipients were males. All patients with cirrhosis were of C-class according to Child-Pugh. The average index of integral liver functionality has been 12.5±1.2 points. Resistant ascitis in preoperative period was detected in 47 patients, in 8 – recurrent episodes of spontaneous bacterial peritonitis, in 6 – II type hepatorenal syndrome. Intraoperative bleeding was 2400±900mL, time of operation – 16±3 hours. The lasting of cold-ischemia was 45±17 min, warm ischemia – 48±12 min. The average duration of postoperative period for recipients was 32±8 days. Early postoperative lethality was noted in 23 cases – 16.1%. Yearly survival – 73.9%, and the actual 5-year survival rate was 66,9%. Conclusions: Living donor transplantation significantly reduces the patient time from waiting-list and increases patient survival rate. The obtained transplantation results are comparable with the results of international studies, and allow us to recommend transplantation for a large group of indications, as a method of selecting treatment for terminal liver pathology patients

    Polyfuran Conducting Polymers: Synthesis, Properties, and Applications.

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    In this review, polyfuran (PFu) synthesis methods and the nucleation mechanism; the electrochemical, structural, morphological, and magnetic properties of PFu; thermal behavior; theoretical calculations on PFu, as well as its applications reported to date, have been compiled. Not only PFu homopolymers have been reviewed, but also PFu co-polymers, PFu bipolymers, and PFu composites. The results are listed, discussed, and compared. It is hoped that this assembly of all the relevant data might enhance knowledge about this conducting polymer and lead to new research fields
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