Mesoscale Simulations of Structure Formation in Polyacrylonitrile Nascent Fibers Induced by Binary Solvent Mixture.

Polyacrylonitrile (PAN) is widely used as a raw material for the production of high-modulus carbon fibers, the internal structure of which is directly affected by the spinning of the precursor. Although PAN fibers have been studied for a long time, the formation of their internal structure has not been sufficiently investigated theoretically. This is due to the large number of stages in the process and the parameters controlling them.

DELAYED SURGERY FOR GIANT SPONTANEOUS RUPTURE OF THE DISTAL THORACIC AORTA CAUSED BY CYSTIC MEDIAL NECROSIS.

Spontaneous (idiopathic) thoracic aortic rupture (STAR) is uncommon and assumes a rupture of the normal-sized thoracic aorta with no visually apparent aortic disease. Since 1961 about fifty reports have been published. STAR is established in cases of thoracic normal-sized aorta rupture with no traumas, aneurysms/dissections, infection, inflammation, connective tissue diseases, aortic and adjacent organs tumors/metastases, previous surgery, and occurring during pregnancy and the peripartum.

Surgery for Ascending Aortic Aneurysm and Aortic Valve Insufficiency in Conditions of Active Proceeding Syphilitic Aortitis and Valvulitis.

A syphilitic aortitis is a late cardiovascular lesion of tertiary syphilis that has become exceptionally rare in the antibiotic era but not eradicated completely. Syphilitic aortitis of ascending aorta complicates in ascending aortic aneurysm formation and aortic valve regurgitation, both requiring surgical treatment. After surgery, lifelong surveillance of the remainder of the aorta is recommended because of a priori supposed high incidence of delayed involvement of noninvolved aortic segments.

Self-assembly in systems based on L-cysteine-silver-nitrate aqueous solution: multiscale computer simulation.

We use fully atomistic, quantum mechanics and mesoscopic simulations to investigate multiscale structure formation in a supramolecular system based on aqueous solutions of silver nitrate with L-cysteine (CSS). Fully atomistic modeling reveals that silver mercaptide clusters are formed in solution at the stage of aging, which has a pronounced "core-shell" structure. The core is formed due to the bonding of SAg groups of silver mercaptide (SM) zwitterions while the shell consists of NH and C(O)O groups.

Effect of visible light onto self-assembly in l-cysteine-silver solution.

Effects of irradiation with visible light on the process of self-assembly in an aqueous l-cysteine-silver solution (CSS) and hydrogels based on were investigated using a set of physico-chemical methods. It was found that the exposure to light of CSS and hydrogels based on l-cysteine and silver acetate colors them firstly into yellow and subsequently to brown, which is due to the plasmon resonance of free electrons at the surface of resulting silver nanoparticles (AgNPs). A mechanism involving participation of AgNPs was proposed for the self-assembly in CSS and hydrogel.

Effect of Nanoparticles Surface Bonding and Aspect Ratio on Mechanical Properties of Highly Cross-Linked Epoxy Nanocomposites: Mesoscopic Simulations.

The paper aims to study the mechanical properties of epoxy resin filled with clay nanoparticles (NPs), depending on their shapes and content on the surface of a modifying agent capable of forming covalent bonds with a polymer. The cylindrical clay nanoparticles with equal volume and different aspects ratios (disks, barrel, and stick) are addressed. The NPs' bonding ratio with the polymer () is determined by the fraction of reactive groups and conversion time and varies from = 0 (non-bonded nanoparticles) to = 0.

Pulmonary valve reconstruction by allograft replacement of underdeveloped anterior leaflet in case of late combined pulmonary restenosis after early primary repair.

Introduction: The native pulmonary valve (PV) reconstruction is an attractive alternative to a replacement but is challenging due to the systematic underdevelopment of the valve structures in congenital heart diseases. The partial replacement of underdeveloped parts of the valve and saving of well-developed may have advantages versus replacing the whole valve in terms of durability and patient outgrowth of the prosthesis.

Case Presentation: This report describes a case of the PV reconstruction by allograft replacement of an underdeveloped anterior leaflet in an adolescent patient who previously corrected pulmonary stenosis during the first year of her life.

Additive-induced ordered structures formed by PCBM fullerene derivatives.

We report the results of an experimental and theoretical study of structure formation in mixtures of phenyl-C-butyric acid methyl ester (PCBM) with high boiling octane based solvent additives 1,8-octanedithiol (ODT), 1,8-dibromooctane, and 1,8-diiodooctane obtained by evaporation of a host-solvent (chlorobenzene). Experimental studies by DSC, SAXS and WAXS methods found evidence of crystallization of fullerenes in the presence of the high boiling additives in the mixtures. A molecular dynamics simulation of a PCBM/ODT mixture revealed the self-assembly of fullerenes into sponge-like network structures.

[The effect of probiotics on the secretory immunity of saliva in patients with type 2 diabetes].

To study the effect of the use of probiotics on the state of mucosal immunity in patients with type 2 diabetes. Evaluation of the results was carried out based on immunological parameters of the saliva of 50 patients suffering from type 2 diabetes with moderate periodontitis, before and 1 month after taking a probiotic complex based on Lactobacillus. In the salivary fluid of patients, a decrease in the concentration of pro-inflammatory cytokines IL-1β, TNF-α and IL-8 was noted, while an increase in the anti-inflammatory cytokine IL-10 was observed.

Primary leiomyosarcoma of inferior vena cava adjacent to hepatic veins: complete off-pump resection and inferior vena cava graft reconstruction with application of external skin surface cooling.

Objectives: Resection of a leiomyosarcoma of the inferior vena cava (IVC) requires venovenous bypass, especially if IVC clamping above the hepatic veins is planned. This report describes the application of external skin surface cooling for off-pump resection of a primary IVC leiomyosarcoma adjacent to the hepatic veins with graft IVC reconstruction in conditions of suprahepatic caval clamping and uninterrupted Pringle's manoeuvre.

Methods: A 62-year-old woman presented with IVC leiomyosarcoma adjacent to the hepatic veins.

[IMMUNE PARAMETERS OF SALIVA IN PERSONS OF DIFFERENT AGE RESIDING IN ST. PETERSBURG AND LENINGRAD REGION].

The article presents the estimation of indicators of saliva secretory immunity in 109 people of different ages (22-90 years) residing in St. Petersburg and the Leningrad region, with no diseases of the salivary glands. The content in saliva IgA, IgM, IgG and secretory IgA, and pro-inflammatory (IL-1β, IL-6, IL-8, TNF-α) and anti-inflammatory (IL-1 receptor antagonist, IL-4, IL-10) cytokines was studied by ELISA.

[Resection of leiomyosarcoma of the inferior vena cava].

Experience in treatment of leiomyosarcoma of the retrohepatic segment of the inferior vena cava at any separately taken clinic is scarce. Given a rare nature of the pathology involved, whose diagnosis and management require joint participation of various-specialty physicians, we have considered it wise to present our own clinical case report.

Dissociation of molecular iodine in a flow tube in the presence of O2(1Σ) molecules.

Molecular iodine dissociates in the presence of O(2)((1)Δ) and O(2)((1)Σ) molecules, but the mechanism of this process is not completely understood. In this paper, using flow tube experiments, we studied the initiation stage of iodine dissociation. Absolute spectral irradiance measurements were employed for measurements of concentrations of electronically excited particles.

Simultaneous multi-vessel coronary artery bypass grafting, ischemic mitral regurgitation repair and descending aortic aneurysm replacement: analysis of technical points.

The combination of coronary artery disease and its complications (ischemic mitral regurgitation etc.) with the aneurysm of the descending thoracic aorta is not a rare case. The single-stage correction of coronary/intracardiac/aortic lesions may be considered as a way of managing the combined patients.

Primary left atrial leiomyosarcoma: literature review and lessons of a case.

Primary cardiac sarcoma is an uncommon disease. In particular, leiomyosarcoma of cardiovascular origin is extremely rare. Half of all cardiac leiomyosarcomas are located in the left atrium.

Surgical angioplasty of the left main coronary artery and/or proximal segment of the right coronary artery by pulmonary autograft patch.

Objectives: There are controversial opinions about the expediency of performance of the surgical angioplasty of the left main coronary artery (LMCA) and/or proximal segment of the right coronary artery (RCA) in rare cases of isolated lesion or with limited involving of distal coronary branches. One of the many fears restraining a wider performance of this operation is the uncertainty in longevity of patch material. It is supposed that the autovein has tendency to proliferating degeneration similar to that in case of coronary artery bypass grafting (CABG), while the autopericardium may be subjected to calcification.

Trace rare gases optical emission spectroscopy: nonintrusive method for measuring electron temperatures in low-pressure, low-temperature plasmas.

Trace rare gases optical emission spectroscopy (TRG-OES) is a new, nonintrusive method for determining electron temperatures (T(e)) and, under some conditions, estimating electron densities (n(e)) in low-temperature, low-pressure plasmas. The method is based on a comparison of atomic emission intensities from trace amounts of rare gases (an equimixture of He, Ne, Ar, Kr, and Xe) added to the plasma, with intensities calculated from a model. For Maxwellian electron energy distribution functions (EEDFs), T(e) is determined from the best fit of theory to the experimental measurements.

[A comparative evaluation of myocardial protection based on criteria not associated with the quality of myocardial conservation].

Based on the rich clinical material (405 patients), the authors have assessed the most common blood and crystalloid cardioplegic techniques by applying the criteria which do not apply to those of myocardial protection adequacy. Differences have been found between the methods in the volumes of blood loss, the number of patients operated on without utilizing donor blood, terms of aortic occlusion at one-stage operative interventions, recovery of cardiac performance after aortic occlusion. The differences found are essential in choosing the type of cardioplegia by taking into account the individual traits of each surgical intervention and an operating surgeon's opinions.

[Massive arterial air embolism--a complication of heart surgery with extracorporeal circulation (clinical picture, prevention, treatment)].

Based on the literature data, the discussion covers the causes, preventive measures, and treatment of massive arterial air embolism, which is one of the most dangerous complications of artificial circulation (AC). Cerebral retroperfusion, hyperbaric oxygenation, low-temperature AC, and long-term administration of antihypoxic agents in the postoperative period have been considered most effective in the management of air embolism. The authors present their experience of successful management of four massive arterial air embolism cases, which is 0.

[Surgical correction of multivalvular defects in patients who had earlier undergone heart surgery].

The article analyses the results of surgical treatment of 45 patients with multivalvular acquired heart diseases which had been previously treated by operation. Stage III (terminal) circulatory disorders were diagnosed in 11 (24.1%) patients.