Validation of a two-fluid turbulence model in comsol multiphysics for the problem of flow around aerodynamic profiles.

The article presents a study of a two-fluid turbulence model in the Comsol Multiphysics software package for the problem of a subsonic flow around the DSMA661 and NACA 4412 airfoils with angles of attack of 0 and 13.87 degrees, respectively. In this paper, the finite element method is used for the numerical implementation of the turbulence equations. To stabilize the discretized equations, stabilization by the Galerkin least squares method was used. The results obtained are compared with the results of other RANS, LES, DES models and experimental data. It is shown that in the case of continuous flow around the DSMA661 airfoil, the results of the two-fluid model are very close to the SST results and are in good agreement with the experimental data. When flowing around the NACA 4412 airfoil, flow separation occurs and a recirculation zone appears. It is shown that in such cases the two-fluid model gives more accurate results than other turbulence models. Implementation of the Comsol Multiphysics software package showed good convergence, stability, and high accuracy of the two-fluid turbulence model.

[Long-term results of surgical correction of H-type fistula in girls with a normal anus]. / Otdalennye rezul'taty khirurgicheskoi korrektsii H-fistul u devochek pri normal'no sformirovannom anuse.

OBJECTIVE: To evaluate the long-term results of surgical correction of H-type fistula in girls with a normal anus. MATERIAL AND METHODS: There were 7 patients with rectovestibular fistula and 3 patients with rectovaginal fistula with a normal anus were observed from 2014 to 2019 in the Surgical Department No. 1 of the Russian Children's Clinical Hospital. Upon admission, all patients underwent genital examination, vaginoscopy, rectal examination and probing the fistulous canal, irrigography, abdominal and retroperitoneal ultrasound. They were also examined by a gynecologist and genital smears were obtained. Surgical treatment was determined depending on the height and diameter of the fistula for each child. One patient underwent perineal fistulectomy, three patients - anterior anorectoplasty. Invaginated fistula extirpation, abdominoperineal proctoplasty and perineal fistulectomy using a pad flap between the defects were used in two cases, respectively. Patients were followed-up for the period from 6 months to 1 year after the last recurrence. Follow-up examination, irrigography and functional examination of sphincter were performed. RESULTS: Two (20%) patients did not require redo surgery. In 6 (60%) cases, recurrences didn't occur within a year after the second surgery, in 2 (20%) cases - after 3 operations. Recurrent H-type fistula appeared after 3 of 4 perineal fistulectomy procedures, 3 of 9 anterior anorectoplasty, 2 of 2 abdominoperineal proctoplasty and 2 of 3 invaginated fistula extirpation. Hypotension of internal anal sphincter and neo-rectal ampulla, recurrent vulvovaginitis were diagnosed in 2 patients in 6 months after anterior anorectoplasty. CONCLUSION: We recommend anterior anorectoplasty and perineal fistulectomy using a pad flap between the defects for the treatment of H-type fistula to minimize the risk of recurrence.

Nanodomain structure of single crystalline nickel oxide.

In this work we present a comprehensive study of the domain structure of a nickel oxide single crystal grown by floating zone melting and suggest a correlation between point defects and the observed domain structure. The properties and structure of domains dictate the dynamics of resistive switching, water splitting and gas sensing, to name but a few. Investigating the correlation between point defects and domain structure can provide a deeper understanding of their formation and structure, which potentially allows one to tailor domain structure and the dynamics of the aforementioned applications. A range of inhomogeneities are observed by diffraction and microscopy techniques. X-ray and low-energy electron diffraction reveal domains on the submicron- and nanometer-scales, respectively. In turn, these domains are visualised by atomic force and scanning tunneling microscopy (STM), respectively. A comprehensive transmission electron microscopy (TEM) study reveals inhomogeneities ranging from domains of varying size, misorientation of domains, variation of the lattice constant and bending of lattice planes. X-ray photoelectron spectroscopy and electron energy-loss spectroscopy indicate the crystal is Ni deficient. Density functional theory calculations-considering the spatial and electronic disturbance induced by the favourable nickel vacancy-reveal a nanoscale distortion comparable to STM and TEM observations. The different inhomogeneities are understood in terms of the structural relaxation induced by ordering of nickel vacancies, which is predicted to be favourable.

Electronic correlation effects and the Coulomb gap at finite temperature.

We have investigated the effect of the long-range Coulomb interaction on the one-particle excitation spectrum of n-type germanium, using tunneling spectroscopy on mechanically controllable break junctions. At low temperatures, the tunnel conductance shows a minimum at zero bias voltage due to the Coulomb gap. Above 1 K, the gap is filled by thermal excitations. This behavior is reflected in the variable-range hopping resistivity measured on the same samples: up to a few degrees Kelvin the Efros-Shklovskii lnR infinity T(-1/2) law is obeyed, whereas at higher temperatures deviations from this law occur. The type of crossover differs from that considered previously in the literature.

[Incidence of urination disorders and erectile dysfunction after surgical treatment of congenital anorectal defects in children]. / Chastota rasstroistv mocheispuskaniia i érektil'nykh disfunktsii posle khirurgicheskoi korrektsii anorektal'nykh porokov razvitiia u detei.

For assessment of the incidence and characteristics of urination disorders and erectile dysfunction after radical surgical treatment of anorectal congenital defects in children, 60 patients (12 girls, 48 boys) without urination disorders before operation, who have undergone 1-4 proctoplasties were examined. Their was Hirschsprung's disease in 20 patients, anorectal atresia in 40 patients. Iatrogenic urination disorders and erectile dysfunction were revealed in 38 (63.3%) patients, majority of them (24) underwent repeated proctoplasty. The main urination disorders were urinary incontinence (30 patients), infravesical obstruction (10), hyporeflexion of urinary bladder. Erectile dysfunction after operation was in 11 (34.4%) patients from 32. The combination of disorders was revealed in 17 (44.7%) patients. Primary radical operations in children with anorectal defects often cause iatrogenic urination disorders and erectile dysfunction. The number of complications increases progressively after repeated proctoplasty. It is necessary to improve the treatment and the methods of surgical correction bearing in mind the risk of iatrogenic disorders of genitourinary apparatus.

[Endourethral correction of valvular obstruction in children]. / Endouretral'naia korrektsia klapannoi obstruktsii u detei.

Endourethral dissection of valvular cusps was carried out by means of an urethrotome in 34 boys with Type I and III valves of the posterior urethra. The indications for and the techniques of the dissection on depending on the type of the valve are discussed and measures for preventing complications are suggested. Endoscopic, radiological, and urodynamic methods of examination of the lower urinary tract determined the therapeutic tactics and help in evaluation of the efficacy of the operative treatment. The method allows correction in patients with valves to be performed in one stage in the compensated stage of the disease and after preliminary derivation of urine in the decompensated stage. The authors recommend optic urethrotomy for the treatment of children with valves of the posterior urethra.

[The cytochemical characteristics of neutrophilic leukocytes in the peripheral blood and synovial fluid of patients with rheumatoid arthritis in the course of treatment]. / Tsitokhimicheskaia kharakteristika neitrofil'nykh leikotsitov perifericheskoi krovi i sinovial'noi zhidkosti u bol'nykh revmatoidnym artritom v dinamike lecheniia.

The authors studied the activity of alkaline and acid phosphatase (AP), myeloperoxidase (MP), the level of cationic protein (CP), spontaneous and pyrogenal-induced tests of restoration of nitroblue of tetrazolium (HCT-test) in the blood and synovial fluid (SF) neutrophils in 116 patients with rheumatoid arthritis (RA) in the dynamics of a 3-4-week and subsequent 6-month therapy with chrysanol, salazopyridazine and delagil. In the active phase all the patients exhibited an abrupt increase in the activity of alkaline and acid phosphatase in blood neutrophils, a drop in the level of CP (in 69%), a rise in the activity of MP (in 32%); pyrogenal did not induce any capacity for restoring HCT (in 44%). Indices of alkaline and acid phosphatase in blood and SF neutrophils and also of the induced TCT-test in blood neutrophils correlated with the degree of RA activity. Statistically significant positive cytochemical shifts were noted only after 6 months of treatment: a decrease in alkaline and acid phosphatase activity, a rise in the level of CP, MP and capacity for restoration pf HCT with pyrogenal in blood neutrophils. Increase in the correlation of CP or MP levels by 0.2 or more in blood and SF neutrophils, and also of the normal level of CP in blood neutrophils or its increase not less than by 15% 3-4 weeks after the beginning of therapy evidence good prognostic informativeness with respect to the effectiveness of basic therapy.

[The diagnostic information value of determining the cytochemical properties of the neutrophils from the blood and synovial fluid of patients with rheumatoid arthritis and osteoarthrosis deformans]. / Diagnosticheskaia informativnost' opredeleniia tsitokhimicheskikh svoistv neitrofilov krovi i sinovial'noi zhidkosti u bol'nykh revmatoidnym artritom i deformiruiushchim osteoartrozom.

Alkaline phosphatase (AP), acid phosphatase and myeloperoxidase (MP) activity and the level of cation protein (CP) in blood and synovial fluid (SF) neutrophils were studied and compared in 54 patients with rheumatoid arthritis (RA) and in 22 patients suffering from primary osteoarthrosis deformans (OAD) combined with reactive synovitis. As compared to the patients with OAD, the patients with RA manifested a significant rise of AP, acid phosphatase and MP activity together with a decrease of the level of CP in blood neutrophils. Meanwhile in SF neutrophils from the patients with RA, all the parameters appeared higher than in OAD and were lower that in blood neutrophils in both the groups. As compared to the routine biochemical and cytological tests, the diagnostic information content of the cytochemical parameters of blood neutrophils (AP, acid phosphatase) and SF neutrophils (AP, acid phosphatase, MP) from the patients with RA (against the patients suffering from OAD) was noticeably higher.

[A comparative assessment of the intensity of cytochemical reactions in blood leukocytes and synovial fluid]. / Sravnitel'naia otsenka intensivnosti tsitokhimicheskikh reaktsii v leikotsitakh krovi i sinovial'noi zhidkosti.

A method for the comparative assessment of the results obtained by Caplow's semiquantitative method and by Actaldi-Verg's technique in cellular populations of varying size is considered, as exemplified by studies of the cytochemistry of the peripheral blood and synovial fluid leukocytes in patients with rheumatoid arthritis.

[Factors affecting the prognosis of neuroblastomas in children]. / Faktory, vliiaiushchie na prognoz pri neiroblastomakh u detei.

A computer analysis of 102 history cases of pediatric neuroblastoma of different localization established certain factors significantly influencing prognosis in this disease. Such factors as treatment modality, stage, patient's age, site and histogenetic pattern of tumor corresponded to the following values of conjugacy coefficient-0.01, 0.02 and 0.05. Treatment modality is of the highest importance. It should be complex and include radiation treatment, surgery and chemotherapy. Radiation treatment (focal dose of not less than 25 Gy) should be supported by combination polychemotherapy. Indications for surgery should be based on stage.

[Diagnosis of uncomplicated compression fractures of the spine in children]. / Diagnostika neoslozhnennykh kompressionnykh perelomov pozvonochnika u detei.

During the first three days after trauma a pronounced hypotonia of muscles independent of the localization of the vertebral column was observed. Two patients of mathematical estimation of the clinoid form of the vertebra were proposed aimed at objectivization of the roentgenological information. In 90% of cases the methods proved to be effective. Gamma scintigraphic examination of the vertebral column was carried out in 101 patients. The results obtained have shown the method to be highly sensitive and objective and to distinguish the normal state, disease and trauma of the vertebral column

[Blood serum somatomedin activity in children with bone tumors]. / Somatomedinovaia aktivnost' syvorotki krovi u detei s opukholiami kostei.

Blood somatomedin levels were assayed biologically in 10 children with Ewing's sarcoma and osteosarcoma and 11 children with other benign tumors. The patients were of the same age. The basal level of somatomedin in malignant bone sarcoma was similar to that in controls. However, after glucose loading, the patterns of somatomedin level curve in children and adults with normal lipo-carbohydrate metabolism were different. The difference may be due either to the specific features of child's organism or a rise in the level of blood somatomedin inhibitors.