Influence of wide band gap oxide substrates on the photoelectrochemical properties and structural disorder of CdS nanoparticles grown by the successive ionic layer adsorption and reaction (SILAR) method

The photoelectrochemical properties of nanoheterostructures based on the wide band gap oxide substrates (ZnO, TiO2, In2O3) and CdS nanoparticles deposited by the successive ionic layer adsorption and reaction (SILAR) method have been studied as a function of the CdS deposition cycle number (N). The incident photon-to-current conversion efficiency (IPCE) passes through a maximum with the increase of N, which is ascribed to the competition between the increase in optical absorption and photocarrier recombination. The maximal IPCE values for the In2O3/CdS and ZnO/CdS heterostructures are attained at N ≈ 20, whereas for TiO2/CdS, the appropriate N value is an order of magnitude higher. The photocurrent and Raman spectroscopy studies of CdS nanoparticles revealed the occurrence of the quantum confinement effect, demonstrating the most rapid weakening with the increase of N in ZnO/CdS heterostructures. The structural disorder of CdS nanoparticles was characterized by the Urbach energy (EU), spectral width of the CdS longitudinal optical (LO) phonon band and the relative intensity of the surface optical (SO) phonon band in the Raman spectra. Maximal values of EU (100–120 meV) correspond to СdS nanoparticles on a In2O3 surface, correlating with the fact that the CdS LO band spectral width and intensity ratio for the CdS SO and LO bands are maximal for In2O3/CdS films. A notable variation in the degree of disorder of CdS nanoparticles is observed only in the initial stages of CdS growth (several tens of deposition cycles), indicating the preservation of the nanocrystalline state of CdS over a wide range of SILAR cycles

Raman study of light-emitting SiNx films grown on Si by low-pressure chemical vapor deposition

Si-rich silicon nitride (SRSN) films were deposited on Si wafers by low pressure chemical vapor deposition (LPCVD) technique and, subsequently, annealed at (800–1200) °C to form Si precipitates. The composition of SiNx films was measured by Rutherford backscattering spectrometry (RBS). Two sets of samples differed by the amount of excessive Si (Siexc) in silicon nitride were studied. Evolution of Si nanoclusters from amorphous to crystalline ones during high temperature treatment was examined by Raman scattering (RS) spectroscopy. The amorphous Si clusters were already revealed in as-deposited SiNx while the annealing results in their crystallization. The crystalline nanoprecipitates are only registered in nitride films after annealing at 1200 °C. A dependence of Raman scattering intensity from the Si wafer on the temperature of annealing of SiNx/Si structures was revealed. This information was used to explain the phase transformations in SRSNs during high temperature treatments. The peculiarities of photoluminescence (PL) spectra for two sets of Si-rich SiNx films are explained taking into account the contribution from the quantum confinement effect of Si nanocrystals and from the native defects in silicon nitride matrix, such as N- and K-centers

The combined method of rectocele treatment

Aim of investigation. To present experience of monitoring of 17 patients with 3-rd degree rectocele by clinical and instrumental tests in the early and remote postoperative periods. Studied patients underwent transrectal circular proctoplasty with plasty of rectovaginal septum by allotransplant.Key points. Operation was pathogenically proved, accompanied by long-lasting clinical effect, low rate of postoperative morbidity and reduces terms of rehabilitation of operated patients.Conclusion. Surgical technique, discussed in the article is efficient method of treatment of rectocele of the 3-rd degree

Experience of Two-Stage Treatment of Rectal Fistulas Using Low-Thrombin Fibrin Glue “Kriofit”

Аim: to improve the results of treatment of patients with rectal fistula.Materials and methods. Twenty-eight patients with rectal fistulas were included in the study — 20 (71,4 %) men and 8 (28,6 %) women, average age — 40 (24–68) years. Based on examination and transrectal ultrasound data, 13 (46.4 %) patients had intrasphincteric fistulas and 15 (53.6 %) had transsphincteric fistulas. All patients underwent prehospital transrectal ultrasound and sphincterometry to assess the functional state of the anal sphincter, and the SF-36 quality of life questionnaire and Wexner scale assessing the functional status of the anal sphincter were analyzed. All patients, included in the study, had straight fistulous passage, without collections and significant scarring of the anal canal. Patients underwent two-stage surgical treatment using low-thrombin fibrin glue “Kriofit”. Follow-up of the patients was carried out on days 7, 14, 21 and included collection of complaints, examination of the perianal area, finger examination of the rectum. In the postoperative period, the intensity of pain syndrome was assessed using the visual analog scale of pain. On days 30 and 90 control transrectal ultrasound, sphincterometry, assessment of Wexner scale and patients' quality of life by SF-36 questionnaire on days 7 and 30 after the operation were performed. Results. There were no intraoperative and early postoperative complications among patients. The average bed-day was 6.8 (5–11) days. The follow-up periods ranged from 1 to 42 months. Disease recurrences were diagnosed in 3 (10.7 %) patients. According to the sphincterometry data, no anal holding dysfunction was detected in any of 28 patients.Conclusion. The results of our study have shown that the division of preliminary surgical treatment of the fistulous passage followed by local anti-inflammatory treatment and filling of the wound canal with two-component fibrin glue with low thrombin content “Kriofit” into two stages effectively increases the results of the proposed technique. The use of fibrin glue as a sphincter-preserving technique makes it possible to exclude the development of postoperative anal incontinence, and new technologies and materials reduce the risk of disease recurrence

Surgical methods of treatment of extrasphincter and transsphincteric fistulas of the rectum (literature review)

The aim of review. To present literature data on surgical treatment of extrasphincteric and transsphincteric fistulas of rectum.Key points. Treatment of fistulas of rectum remains a challenge because of risk of frequent relapses varying from 4,7 to 60%. Radical treatment methods are overly traumatic and result in severe fibrotic changes in the anal canal structures that are accompanied by high risk of anal sphincter incompetence - up to 83%. Now highly effective methods with application of various implants to eliminate tissue defect and improve regeneration are presented in the literature more and more commonly. Application of collagenic implants allows to decrease traumatization of sphincter fibres and thus to reduce to minimum risk of anal sphincter incompetence.Conclusion. Elimination of postoperative anal incontinence is a priority task in treatment of extrasphincter fistulas of rectum

Experience of treatment of presacral tumors

Aim of investigation. Improvement of presacral tumors treatment results.Material and methods. Data of surgical treatment 21 patients with true presacral tumors, operated in Federal government-financed institution «Ryzhikh State Scientific Center of Coloproctology», Ministry of healthcare of the Russian Federation with 2004 on 2013 was analyzed. Study group included 16 women (76%) and 5 men (24%) with mean age of 46,3±15,1 years.Results. Tumor relapse was revealed in 4 (5,6%) of operated patients, tumors in these cases had various histological structure.Conclusion. Experience of surgical interventions at benign retrorectal presacral tumors allows to consider surgical method as adequate treatment approach. The highest relapse rate was observed at malignant tumors; such patients require the combined treatment at specialized oncologic clinic. The choice of surgical access is determined, first of all, by neoplasm localization

Raman Study of CVD Graphene Irradiated by Swift Heavy Ions

CVD-graphene on silicon was irradiated by accelerated heavy ions (Xe, 160 MeV, fluence of 1011 cm-2) and characterized by Raman spectroscopy. The defectiveness of pristine graphene was found to be dominated by grain boundaries while after irradiation it was determined by both grain boundaries and vacancies. Respectively, average inter-defect distance decreased from ~ 24 to ~ 13 nm. Calculations showed that the ion irradiation resulted in a decrease in charge carrier mobility from ~ 4.0 × 103 to ~ 1.3·103 cm2/V s. The results of the present study can be used to control graphene structure, especially vacancies concentration, and charge carrier mobility

Ilaser Submucous Destruction in the Treatment of Hemorrhoids

Aim: to improve the results of treatment in patients with hemorrhoids of the 2nd and 3rd stages.Materials and methods. The prospective study included 60 patients with hemorrhoids of the 2nd and 3rd stages. All patients underwent destruction of internal hemorrhoids with a fiber laser with a diode pump with a wavelength of 1940 nm. The technique is based on the effect of laser energy on the cavernous tissue of the internal hemorrhoidal node and on the terminal branches of the upper rectal artery. The efficiency of the destruction of internal hemorrhoids and the frequency of relapses of the disease were evaluated. The effectiveness of the proposed method was evaluated using anoscopy, measurement of the size of internal hemorrhoidal nodes, transrectal ultrasound with dopplerography. The analysis of the intensity of the pain syndrome, the consumption of nonsteroidal anti-inflammatory drugs and the assessment of the quality of life on the SF-36 scale was carried out. Sphincterometry was performed in all patients to determine the possible effect of laser radiation on the rectal locking apparatus. To assess the possible causes of complications, a single-factor analysis of the amount of energy transferred to each hemorrhoidal node and the total amount of energy spent on the operation was conducted.Results. In all patients, by day 7 after surgery, the pain syndrome in 43 patients (75.4 %) corresponded to 0 points according to VAS. In 3 patients (5 %) intraoperative hemorrhage developed. In the early postoperative period, 5 patients (8.3 %) had 7 complications: 5 cases of thrombosis of the external hemorrhoidal node and 2 — of acute urinary retention. The conducted single-factor analysis showed the dependence of the development of complications on the energy transferred to each hemorrhoidal node and its total amount for the entire operation. In terms of up to 6 months, there were no signs of a return of the disease in any case (hemorrhoidal prolapse and blood discharge). The detected hemorrhoids before the operation, a month after the operation, were not visualized, which persisted after 6 months. The performed transrectal ultrasound examination with spectral-wave dopplerography for up to 6 months allowed to diagnose a persistent decrease in blood flow along the terminal branches of the upper rectal artery compared with preoperative values. When performed sphincterometry, there was no change in the parameters of the anal sphincter function compared to preoperative parameters.Conclusion. The proposed method applying a fiber laser with a diode pump with a wavelength of 1940 nm makes it possible to affect transdermally the internal hemorrhoidal node without damaging the mucosa of the anal canal. The absence of postoperative wounds in the anal canal leads to a decrease in pain syndrome, and by day 7 there are no clinical manifestations of hemorrhoids. The method of laser destruction of internal hemorrhoids can be used in outpatient conditions and can improve the quality of life of patients in the early postoperative period

Treatment of rectal fistulas with application of unreconstructed collagen

Aim of investigation. To improve results of treatment of extrasphincter and transsphincteric fistulas of rectum.Material and methods. Treatment experience of 70 patients aged 22 to 61 years with extrasphincteric and transsphincteric rectal fistulas using new surgical technique: resection of fistulous tract, internal ostium plastic by allocollagen membrane and sealing of excised fistulous tract by bioplastic material is presented.Results. In remote postoperative period, in 5 months to 3 years, 45 (64,3 %) patients were followed-up. In 4 (5,7%) patients relapse of disease was detected: in 3 (4,3%) cases fistula relapse in its initial location, these patients underwent segmentary proctoplasty, the fistula was closed, in one case (1,4%) after 2 months postsurgery intrasphincteric fistula was found that required resection into intestinal lumen. Good functional results were confirmed by sphincterometry and profilometry both in preoperative period, and in 3 months after surgery in 15 (21,4%) patients. No decrease of obturative rectum device scores was revealed.Conclusion. Application of bioplastic material can be technique of choice at treatment of extrasphincter and transsphincteric fistulas with involevement of deep portion of sphincter

Micro Raman investigation of graphene synthesized by atmospheric pressure CVD on copper foil from decane

In this article we present the results of micro-Raman studies of graphene grown on copper foil surface by atmospheric pressure CVD using decane as precursor, nitrogen as carrier gas with zero flow of hydrogen. Analysis of Raman spectroscopy data showed that film contains spots with single layer thick graphene. We observed significant blue shift of 2D and G bands positions for mono-atomically thick graphene on copper foil. Following literature we relate this shift to the strain induced by the presence of copper substrate. Moreover, we observed changes in the defectiveness of graphene layers after the transfer, which was related to the appearance of chemically-induced defects and defects induced by changes in the mechanical strain