Laser-Induced Periodic Surface Structures on Layered GaSe Crystals: Structural Coloring and Infrared Antireflection.

We study structural and morphological transformations caused by multipulse femtosecond-laser exposure of Bridgman-grown ϵ-phase GaSe crystals, a van der Waals semiconductor promising for nonlinear optics and optoelectronics. We unveil, for the first time, the laser-driven self-organization regimes in GaSe allowing the formation of regular laser-induced periodic surface structures (LIPSSs) that originate from interference of the incident radiation and interface surface plasmon waves. LIPSSs formation causes transformation of the near-surface layer to amorphous Ga2Se3 at negligible oxidation levels, evidenced from comprehensive structural characterization. LIPSSs imprinted on both output crystal facets provide a 1.2-fold increase of the near-IR transmittance, while the ability to control local periodicity by processing parameters enables multilevel structural color marking of the crystal surface. Our studies highlight direct fs-laser patterning as a multipurpose application-ready technology for precise nanostructuring of promising van der Waals semiconductors, whose layered structure restricts application of common nanofabrication approaches.

[Creatine phosphokinase as a predictor of acute destructive cholecystitis]. / Kreatinfosfokinaza kak prediktor ostrogo destruktivnogo kholetsistita.

OBJECTIVE: To analyze creatine phosphokinase as a predictor of destructive cholecystitis. MATERIAL AND METHODS: We analyzed 105 patients with various clinical variants of acute calculous cholecystitis (catarrhal, phlegmonous, gangrenous), and comparable age, gender and comorbidities. The study included patients with gallstone disease and gallbladder inflammation aged 30-7 years who underwent laparoscopic cholecystectomy, open cholecystectomy, cholecystectomy through mini-laparotomy. We excluded patients with gallstone disease complicated by mechanical jaundice aged under 30 years and over 70 years old. Control group consisted of 35 patients with exacerbation of chronic calculous cholecystitis. Creatinine phosphokinase (CPK) was analyzed at admission by standard kinetic colorimetric method in all patients with suspected acute cholecystitis. Statistical analysis of data was carried out using the SPSS Statistics 7.0 software in compliance with the principles of statistical analysis adopted for research in biology and medicine. RESULTS: CPK level was 257.7±27.9 U/L (p<0.05) in patients with acute calculous cholecystitis that is 3.5 times higher than in the control group. We found an increase of concentration of this enzyme depending on severity of gallbladder wall destruction. CONCLUSION: Analysis of serum creatine phosphokinase can be included in the algorithm of preoperative examination to study the prospects of this approach for predicting severity of acute cholecystitis.

[Retroperitoneal drainage for apostematous pyelonephritis in a patient with severe COVID-19 infection and diabetes mellitus type 1]. / Retroperitoneal'noe drenirovanie pri apostematoznom pielonefrite na fone tyazhelogo techeniya Covid-19 pri sakharnom diabete 1-go tipa.

The authors report successful surgical treatment of apostematous pyelonephritis complicated by sepsis in an 18-year-old patient with severe COVID-19 pneumonia (CT-2) and diabetes mellitus type 1. Active surgical approach with retroperitoneal drainage and decapsulation of the right kidney ensured positive dynamics in the treatment of destructive pyelonephritis, course of diabetes mellitus and elimination of sepsis. These aspects determined favorable outcome of disease.

[Surgical procedures at the city hospital for patients with Covid-19. A 9-month experience]. / Khirurgicheskie vmeshatel'stva v gorodskoi bol'nitse v period ee deyatel'nosti v kachestve monostatsionara dlya patsientov s Covid-19. Devyatimesyachnyi opyt.

OBJECTIVE: To report our experience in surgical treatment of patients with COVID-19. MATERIAL AND METHODS: There were 7815 patients with COVID-19 for the period from April 1, 2020 to December 31, 2020. During this period, 172 operations were performed in this group. RESULTS: The most common procedures were tracheostomy (n=86, 50.0%), pleural puncture and drainage (n=20, 11.6%), caesarean section (n=22, 12.7%). There were 24 (14.0%) abdominal surgeries including 11 laparoscopies, 5 appendectomies, 3 bowel resections and others. Six lower limb amputations were carried out. We should emphasize common soft tissue hematomas and effusions. This complication is associated with anticoagulation recommended for patients with COVID-19. CONCLUSION: Surgical interventions using personal protective equipment is a significant challenge. According to our experience, round-the-clock surgical care in a specialized hospital is required.

[Retroperitoneoscopic technologies in retroperitoneal procedures].

The active development of minimally invasive procedures on retroperitoneal organs using endoscopic technology raises the question of the most rational approach. The studies dedicated to the comparison of transperitoneal and retroperitoneoscopic approach are analyzed in the article. The advantages and the most common complications, as well as the factors limiting the widespread use of retroperitoneoscopic approach, are reviewed.

Optical and electronic properties of lithium thiogallate (LiGaS2): experiment and theory.

We report the relation between the optical properties and electronic structure of lithium thiogallate (LiGaS2) by performing XPS and XES measurements and theoretical calculations. According to the XPS measurements, the LiGaS2 crystals grown by the Bridgman-Stockbarger method possess promising optical qualities, low hygroscopicity and high stability upon middle-energy Ar+-ion irradiation. The difference in the LiGaS2 band gaps obtained by theoretical calculations and experimental measurements was, for the first time, reduced down to 0.27 eV by applying the Tran-Blaha modified Becke-Johnson (TB-mBJ) potential where the Coulomb repulsion was considered by introducing Hubbard parameter, U. The TB-mBJ+U method also reproduces the XPS spectrum well. The TB-mBJ+U band-structure calculations of LiGaS2 are found to be in good agreement with the XPS and XES experimental data. The accurate electronic structure of LiGaS2 allows further investigation of the optical properties. The relation between the photoluminescence of LiGaS2 and its electronic structure was revealed. Moreover, the theoretical results show the possibility of emissions at higher energy levels in LiGaS2, that has not been measured in experiments yet. Good phase-matching of LiGaS2 was expected to occur at energy levels of 5, 6, 6.2, 7, 7.2, and 8 eV.

Efficient quantitative hyperspectral image unmixing method for large-scale Raman micro-spectroscopy data analysis.

Vibrational micro-spectroscopy is a powerful optical tool, providing a non-invasive label-free chemically specific imaging for many chemical and biomedical applications. However, hyperspectral image produced by Raman micro-spectroscopy typically consists of thousands discrete pixel points, each having individual Raman spectrum at thousand wavenumbers, and therefore requires appropriate image unmixing computational methods to retrieve non-negative spatial concentration and corresponding non-negative spectra of the image biochemical constituents. Here, we present a new efficient Quantitative Hyperspectral Image Unmixing (Q-HIU) method for large-scale Raman micro-spectroscopy data analysis. This method enables to simultaneously analyse multi-set Raman hyperspectral images in three steps: (i) Singular Value Decomposition with innovative Automatic Divisive Correlation which autonomously filters spatially and spectrally uncorrelated noise from data; (ii) a robust subtraction of fluorescent background from the data using a newly developed algorithm called Bottom Gaussian Fitting; (iii) an efficient Quantitative Unsupervised/Partially Supervised Non-negative Matrix Factorization method, which rigorously retrieves non-negative spatial concentration maps and spectral profiles of the samples' biochemical constituents with no a priori information or when one or several samples' constituents are known. As compared with state-of-the-art methods, our approach allows to achieve significantly more accurate results and efficient quantification with several orders of magnitude shorter computational time as verified on both artificial and real experimental data. We apply Q-HIU to the analysis of large-scale Raman hyperspectral images of human atherosclerotic aortic tissues and our results show a proof-of-principle for the proposed method to retrieve and quantify the biochemical composition of the tissues, consisting of both high and low concentrated compounds. Along with the established hallmarks of atherosclerosis including cholesterol/cholesterol ester, triglyceride and calcium hydroxyapatite crystals, our Q-HIU allowed to identify the significant accumulations of oxidatively modified lipids co-localizing with the atherosclerotic plaque lesions in the aortic tissues, possibly reflecting the persistent presence of inflammation and oxidative damage in these regions, which are in turn able to promote the disease pathology. For minor chemical components in the diseased tissues, our Q-HIU was able to detect the signatures of calcium hydroxyapatite and ß-carotene with relative mean Raman concentrations as low as 0.09% and 0.04% from the original Raman intensity matrix with noise and fluorescent background contributions of 3% and 94%, respectively.

[Contact lithotripsy in treatment of choledocholithiasis].

It was suggested to use contact ultrasonic lithotripsy in lumen of common bile duct during laparoscopic surgery in order to preserve the sphincter apparatus of major duodenal papilla. Waveguide with original structure was used for lithotripsy performing. Waveguide's total length is 400 mm. It has a radially curved 40 degrees broken part with diameter of 6 mm cone rolling in working portion with diameter of 4 mm and length of 60 mm for introduction in common bile duct. There is concave lens on waveguide working portion end with diameter of 1 mm. A lens permits concentrating the waves beam in longitudinal direction avoiding its scattering and minimizing the impact on surrounding tissues. Lithotripsy efficiency was proved in the in vitro (n=68) and in vivo (n=20) experiments. Such structure of waveguide permits to penetrate in lumen of common bile duct through dilated cystic duct or choledochendysis for calculi fragmentation.

[Gerontological features of changes in indicators of lipid peroxidation and antioxidant enzymes in the wall of the small bowel in patients with acute severe peritonitis].

The aim of the work was to study age related changes of lipid peroxidation and antioxidant system in the wall of the small bowel in patients with severe secondary peritonitis. Group I, control (n=42) was consisted of patients from 30 to 89 years. Age of the group II patients (n=36) was from 30 to 59 years, III (n=43) from 60 to 74 years and IV (n=28) from 75 to 89 years. The obtained results of the study showed a significant increase in the concentration of conjugated dienes in the wall of the small intestine, especially in third grade enteric insufficiency as in patients of the second group, which amounted 0,34±0,03 s.u./mg of lipids, and in elderly patients - 0,38±0,03 cu./mg of lipids and senile patients 0,42±0,04 s.u./mg of lipids. On increasing the concentration of the toxic products of lipid peroxidation in the intestinal wall testified a negative accumulation of malondialdehyde from 6,91±0,38 nmol/g protein in patients of the second group, even with second degree enteral insufficiency to 7,49±0,51 nmol/g of protein for elderly patients (fourth group).

[Some features of the modeling and age differences of the course of acute experimental peritonitis].

Investigations were carried out on 24 white Wistar rats which, depending on age were divided into two groups: the first 6 months, the other 12 months. Using the priority method of autointestine (20% mixture of the colon at the rate of 1.0 ml per 100 g of weight of test animal) modeling peritonitis enabled reproduce the disease process adequately and set the age differences. In experimental animals 12 months of peritonitis 18 hours, as opposed to six month, it has been a significant deterioration in hemodynamics with reduction of systolic blood pressure to 83,18±2,98 mm.Hg and diastolic blood pressure up to 64,59±5,43 mm.Hg. In addition, there has been differences in the toxicity of enteric contents, as evidenced by the decrease in pH to 4,06±0,28 and reducing the time paramecium test to 3,12±0,14 minutes. The results of experimental studies have also been installed significant age differences transintestinal redistribution of toxic substances. The 12 month animals predominate intestine-portal contamination, which was expressed in increasing concentration of AMW-280 and 0,45±0,03 S.U., LII to 2,58±0,11 and lower Paramecium test to 5,44±0,26 minutes. Thereby, the modeling of experimental peritonitis of 18 hours there were significant age differences in the pace and extent redistribution of contamination processes that lead to the aggravation of the generalization of the pathological process, which requires the development of modern methods of intra-operative intra-abdominal correction.

A luminescence spectroscopy and theoretical study of 4f-5d transitions of Ce3+ ions in SrAlF5 crystals.

This research is focused on the 4f-5d transitions in Ce(3+) centers doped into tetragonal ß-SrAlF(5) single crystals belonging to the I4(1)/a space group. The presence of four non-equivalent Sr(2+) sites in this compound leads to the appearance of three spectroscopically non-equivalent Ce(3+) luminescence centers, which can be well distinguished using a time-resolved laser spectroscopy technique. All 4f-5d transitions have slightly varying excitation and emission energies with characteristic probabilities resulting in several decay times that can be determined experimentally. One of these centers experiences strong perturbation due to a defect nearby, probably the O(2-) impurity ion substituting for the F(-) ion and acting as a charge compensator as well. Identification of these photoluminescence centers is performed using crystal field calculations. The crystal field parameters are calculated for two identified centers using the structural data for SrAlF(5); diagonalization of the crystal field Hamiltonian results in obtaining the splitting of the Ce(3+) 5d states. This method allows 'regular' unperturbed Ce(3+) centers with selected Sr(2+) sites to be assigned.

[Lipid peroxidation and antiradical defense in patients after endosurgical cholelithiasis].

The peroxide status was studied after cholecystectomy depending on the procedure of a surgical access and the duration of exposure to the pneumoperitoneum during laparoscopic operations. Endosurgical interventions, unlike open operations and miniaccess operations, were found to have the least impact on the values of lipid peroxidation (LPO) expirate. There was evidence that a marked imbalance occurred in the LPO-antioxidant system with longer exposure to the peritoneum.

Optical properties of LiGaS(2): an ab initio study and spectroscopic ellipsometry measurement.

Electronic and optical properties of lithium thiogallate crystal, LiGaS(2), have been investigated by both experimental and theoretical methods. The plane-wave pseudopotential method based on DFT theory has been used for band structure calculations. The electronic parameters of Ga 3d orbitals have been corrected by the DFT+U methods to be consistent with those measured with x-ray photoemission spectroscopy. Evolution of optical constants of LiGaS(2) over a wide spectral range was determined by developed first-principles theory and dispersion curves were compared with optical parameters defined by spectroscopic ellipsometry in the photon energy range 1.2-5.0 eV. Good agreement has been achieved between theoretical and experimental results.

Morphofunctional changes in mitochondria during stress.

Electron microscopy revealed morphofunctional changes in mitochondria of rats under stress conditions. Reparative processes and pathomorphological changes were monitored. Heterogeneous ultrastructural changes in mitochondria were revealed.

Mid-infrared (2.75-6.0-microm) second-harmonic generation in LiInS(2).

Phase-matched second-harmonic generation is obtained in various LiInS(2) crystals by use of the tunable picosecond output of the free-electron laser for infrared experiments (FELIX) as the pump source in the mid-IR range from 2.75 to 6.0 microm. Deviations from the phase-matching curve calculated from Boyd's refractive-index data are observed. Furthermore, the optical damage threshold of the crystals has been measured to be 1.1. J/cm(2)(>6 GW/cm(2)) at the 5-microm wavelength. LiInS(2) holds great promise for parametric interaction in the 1-13-microm range.

Compact, broadly tunable, mid-IR source for the spectroscopic investigation of molecular reference lines in the 27- to 33-THz range.

We report on the improvement of a tunable, high resolution, diode laser-based, difference-frequency spectrometer using an AgGaS(2) nonlinear crystal. We use a type-II cut crystal as a part of the improvement compared with a type-I cut, which was used in our preliminary setup. The two tunable laser-diodes are operating near lambda(3)=778 nm (pump) and lambda(2)=842 nm (signal) with a sub-100-kHz linewidth. The high resolution spectrometer is being developed as an alternative to CO(2) laser spectrometers in the 9- to Il-mum range. Using a dual-arm cavity to enhance the two radiation powers, and with 35 mW in front of the 778-nm arm and 100 mW in front of the 842 nm arm, about 70 nW of the tunable 10-mum radiation are generated. This power level is enough to investigate the linear absorption spectroscopy of SF(6). Doppler-limited spectra over 2 GHz, are recorded, showing the wide continuous tunability of the spectrometer.

Toward a 3:1 frequency divider based on parametric oscillation using AgGaS(2) and PPLN crystals.

Frequency divide-by-two (2:1) and divide-by-three (3:1) optical parametric oscillators (OPOs) are basic devices for the implementation of future accurate optical frequency division chains. We report our latest development toward a phase-locked 3:1 frequency division of a radiation at lambda(p) approximately 843 nm (355.9 THz), using doubly resonant oscillators (DROs) based on silver gallium sulfide (AgGaS(2 ) or AGS) and multigrating periodically poled lithium niobate (PPLN). Although stable single-mode pair operation is achievable without any active cavity length servo with the AGS-DRO, because of a strong passive thermal feedback servo, the PPLN-DRO requires an active intensity side-of-fringe locking servo to maintain long-term, single-mode pair operation. To overcome the limited idler output power (<1 mW) due to the weak mirror transmissivity at 2.53 mum, a CaF (2) Brewster-oriented plate was inserted in a longer-cavity PPLN-DRO as a variable output coupler. About 3 mW of idler wave is thus coupled outside the cavity, yielding 15 nW of doubled-idler. We obtained a 30 dB signal-to-noise ratio beatnote in a 100 kHz resolution bandwidth of a spectrum analyser. This beat signal will be used to phase-lock the divider.

[Effects of presensitization and clinical death in the history on the dynamics of morphofunctional parallels of retinal and cerebral circulation]. / Vliianie predvaritel'noi sensibilizatsii i perenesennoi klinicheskoi smerti na dinamiku morfofunktsional'nykh parallelei retinal'nogo i mozgobogo krovotoka.

A negative effect of preliminary sensibilization with a normal serum and clinical death (restoring to life according to V. A. Negovsky et al.) on cerebral blood supply and eye retina within 5 weeks of postresuscitation period was studied on dogs. Microcirculation disorders in the groups of sensibilized dogs were more prominent as compared to intact animals. The diameter changes of pial and retinal microvessels did not correlate, but qualitative alterations in retinal and cerebral microvessels were of the same type.

[A new transplant for iridoplasty]. / Novyi transplantat dlia iridoplastiki.

A new transplant is proposed for replacing extensive defects of the iris: cadaveric aortic wall. Experiments demonstrated that taking in of this graft courses as incomplete regeneration with partial taking in and replacement of the graft by cell elements of the iris with the formation of a cicatrice. Aortic wall transplant was used in the treatment of 4 patients.