Gamma-ray dose threshold for MAPbI3 solar cells.

In this work, we report on the effects observed in MAPbI3 polycrystalline films and solar cells under moderate gamma-ray doses of 3-21 kGy. We applied several instrumental techniques such as photoluminescence spectroscopy, time-resolved photoluminescence, Suns-VOC measurement, and impedance spectroscopy to characterize exposed samples. We observed a nonlinear dependency of such characteristics as PL intensity, career lifetime, ideality factor, and recombination resistance on the exposure dose. Small doses of 3-5 kGy annihilate some of the defect centers in the material, which results in improved carrier extraction and prolonged carrier lifetime, while with larger doses of 10 kGy and above, nonradiative recombination becomes predominant. In this way, we revealed a gamma-ray threshold for MAPbI3 films of around 10 kGy, above which it is not recommended to exploit this material. In space environment, yearly doses rarely exhibit 0.1 kGy (10 krad), and the MAPbI3 material has a sufficient margin of safety for space applications. Moreover, this unusual behaviour opens up the opportunity to use gamma-ray sources as an effective method to improve the quality of defective polycrystalline perovskite films before actual exploitation in an ionizing radiation-free environment.

Light-emitting diodes with Ge(Si) nanoislands embedded in photonic crystals.

Room temperature lateral p+-i-n+light-emitting diodes (LEDs) with photonic crystals embedded in the i-region were fabricated on structures with Ge(Si) self-assembled islands and their optical properties were investigated. The use of preliminary amorphization and solid phase epitaxy of the implanted p+and n+contact regions made it possible to reduce the impurity activation temperature from 800 °Ð¡-1100 °Ð¡ to 600 °Ð¡, which corresponds to the growth temperature of Ge(Si) islands. This resulted in a significant reduction of the detrimental effect of the high-temperature annealing used for diode formation on the intensity and spectral position of the luminescence signal from the islands. It was shown that significant enhancement (more than an order of magnitude) of room temperature electroluminescence of Ge(Si) islands in the spectral range of 1.3-1.55µm can be achieved due to their interaction with different modes of the photonic crystals. The measured radiation power of the obtained diodes in the spectral range of 1.3-1.55µm exceeds 50 pW at a pump current of 8 mA, which is an order of magnitude higher than the previously achieved values for micro-LEDs with Ge(Si) nanoislands. The obtained results open up new possibilities for the realization of silicon-based light emitting devices operating at telecommunication wavelengths.

[The analysis of secondary AA-amyloidosis current etiology and its influence on the approaches for diagnosis and treatment].

AIM: To investigate an influence of the currently changed etiologic structure of AA-amyloidosis on the diagnosis and treatment tactics. MATERIALS AND METHODS: In 110 patients with АА-amyloidosis followed during full disease duration (1 month 29 years) etiology, clinical manyfestations and approaches to diagnose and treatment of AA-amyloidosis were evaluated. With ELISA levels of amyloid precursor acute phase inflammation reactant SAA and neutrophil activity marker S100A12 were measured. RESULTS: Among the most common causes of AA-amyloidosis at the present stage, in addition to RA (40.3%), a significant place is occupied by a group of diseases with a predominantly autoinflammatory mechanism (53.73%). To confirm the autoinflammatory mechanism of the predisposing disease it is recommended to study a highly sensitive parameter serum protein S100A12. An effective marker of the risk of AA-amyloidosis progression, especially in patients with subclinical activity of inflammatory disease, is a high level of production of amyloidogenic protein-a precursor of SAA.

[Complex rehabilitation of a patient with marked motor and cognitive impairments after a brain injury]. / Kompleksnaya reabilitatsiya patsienta posle tyazheloi zakrytoi cherepno-mozgovoi travmy s vyrazhennymi dvigatel'nymi i kognitivnymi narusheniyami.

In the presented case report, the complex approach of rehabilitation in the remote period of traumatic brain injury (TBI) allowed the achievement of the significant clinical effect. The authors analyzed the experience of reflex therapy in the treatment of TBI. The effectiveness and potential of acupuncture, objectification of the results are topical issues that require further research.

Preservation of Mesenchymal Stem Cell-Derived Extracellular Vesicles after Abdominal Delivery in the Experiment.

Light luminescent microscopy was used to study the distribution of extracellular microvesicles with PKH26-stained membranes secreted by placenta-derived mesenchymal stromal cells in the uterine tissues at different terms after injections to intact rats and after abdominal delivery (a model of cesarian section). Microvesicles migrated through the uterine tissues and were detected for at least 8 days after injection. In some cases, microvesicles were more numerous in the uterus after cesarian section modeling, which can be related to blockade of microcirculation and lymph flow due to inflammation accompanying surgical intervention. The content of microvesicles in the uterine tissues gradually declined due to macrophage phagocytosis and, probably, due to their migration into the vascular bed. Despite their size, properly stained extracellular microvesicles can be detected by light microscopy in tissues after injections.

Towards the indium nitride laser: obtaining infrared stimulated emission from planar monocrystalline InN structures.

The observation of a stimulated emission at interband transitions in monocrystalline n-InN layers under optical pumping is reported. The spectral position of the stimulated emission changes over a range of 1.64 to 1.9 µm with variations of free electron concentration in InN layers from 2·1019 cm-3 to 3·1017 cm-3. The main necessary conditions for achieving the stimulated emission from epitaxial InN layers are defined. In the best quality samples, a threshold excitation power density is obtained to be as low as 400 W/cm2 at T = 8 K and the stimulated emission is observed up to 215 K. In this way, the feasibility of InN-based lasers as well as the potentials of crystalline indium nitride as a promising photonic material are demonstrated.

[Carotid endarterectomy and stenting in patients with internal carotid artery stenosis and contralateral occlusion]. / Karotidnaia éndarteréktomiia i stentirovanie u bol'nykh s gemodinamicheski znachimym stenozom vnutrennei sonnoi arterii i kontralateral'noi okkliuziei.

AIM: To determine surgical risk factors and to compare early outcomes after carotid endarterectomy and carotid stenting in patients with internal carotid artery stenosis and contralateral occlusion. MATERIAL AND METHODS: 132 patients were enrolled. 62 and 70 patients underwent carotid endarterectomy and carotid stenting respectively. Early postoperative results were compared depending on type of surgical intervention and presence of risk factors. RESULTS: Significant difference between groups was only found for incidence of neuropathy of the cranial nerves. It was established that cardiac comorbidities are risk factors for adverse events after carotid endarterectomy. Stable (homogeneous) atherosclerotic plaque with clear contour and no ulceration is optimal for carotid stenting.

Electrically pumped InGaAs/GaAs quantum well microdisk lasers directly grown on Si(100) with Ge/GaAs buffer.

In this work we report, to the best of our knowledge, the first quantum well electrically-pumped microdisk lasers monolithically deposited on (001)-oriented Si substrate. The III-V laser structure was epitaxially grown by MOCVD on silicon with an intermediate MBE-grown Ge buffer. Microlasers with an InGaAs/GaAs quantum well active region were tested at room temperature. Under pulsed injection, lasing is achieved in microlasers with diameters of 23, 27, and 31 µm with a minimal threshold current density of 28 kA/cm2. Lasing spectrum is predominantly single-mode with a dominant mode linewidth as narrow as 35 pm.

[Surgical treatment of patients with haemodynamically significant stenosis of the internal carotid artery and contralateral occlusion]. / Khirurgicheskoe lechenie bol'nykh s gemodinamicheski znachimym stenozom vnutrennei sonnoi arterii i kontrlateral'noi okkliuziei.

Presented herein is a review of the literature dedicated to the problem regarding surgical management of patients with haemodynamically significant stenosis of the internal carotid artery and collateral occlusion. Special consideration is given to the studies comparing perioperative and early postoperative outcomes of carotid endarterectomy in patients with the nosology concerned. The literature was retrieved by means of the following databases Scopus, Web of Science, Medline, and the Russian Science Citation Index.

[Automated decision making support system for urologists on the prediction and the prevention of stone formation in urolithiasis].

This article describes a decision making support system for urologists on the prediction and management of preventive interventions for urolithiasis using fuzzy logic decision-making device. Dictionary of informative signs and alphabet of classes are formed. The formulas for calculating the membership functions according to the known features are developed; these formulas allow to calculate the certainty factors for pertaining of inspected object to the desired class by means of iterative rules of rule of logical inference. Based on comparison of the values obtained with the threshold certainty factors, dephasification of conclusion is produced. In accordance with the obtained decision rules, control algorithm for the prevention measures in urolithiasis is developed. To test the effectiveness of "operation" of the synthesized decision rules, the certainty factors were calculated or 200 patients with urolithiasis, which were divided into two groups according to the results of observation during the year depending on the presence of recurrence. The analysis of the intersection of histograms of distribution of coefficient values showed high diagnostic efficiency (0.94) of synthesized decision rules.

Binding of sterols affects membrane functioning and sphingolipid composition in wheat roots.

The present work was devoted to the exploration of the role of sterols in the functioning of membranes in root cells. Membrane characteristics and composition of the membrane lipids in the roots of wheat (Triticum aestivum L.) seedlings treated with exogenous cholesterol and antibiotic nystatin, which specifically binds with endogenous sterols, were analyzed. Cholesterol caused a fall of membrane potential, acidification of the incubation medium, decrease in potassium leakage of roots, and increase in the level of exogenous superoxide radical. Similarly to cholesterol, the application of nystatin also induced the depolarization of the plasma membrane, but in contrast with cholesterol it was accompanied by alkalinization of the incubation medium and decrease in the level of exogenous superoxide radical. Analysis of membrane lipids showed that following nystatin treatment the total sterol content in roots did not change, while the level of complex sphingolipids represented mainly by glycoceramides became higher. Using mass spectrometry with electrospray ionization ((+)ESI-MS) for the analysis of the glycoceramide composition, we showed that nystatin induced changes in the ratios of molecular species of glycoceramides. It was suggested that the modification of the sterol component of plasma membrane could influence membrane functioning by changing the sphingolipid composition of lipid rafts.

ESI-MS studies of silver ion competitive interaction with cysteine-containing peptides and sulfur-containing amino aсids.

The paper deals with investigation of silver ion interaction with sulfur-bearing amino acids and cysteine-bearing peptides using an electrospray ionisation orthogonal ion introduction time-of-flight (ESI-o-TOF) mass spectrometer. It has been shown that Cys and Hcy demonstrate the largest affinity for silver, both in relation to methionine and cysteine residues in peptides. The studies have for the first time revealed the effect of predominant forming of ions containing two silver atoms per a sulfhydryl group of cysteine-bearing peptides if the nearest microenvironment does not hinder this.

[Ligands of glutamate and dopamine receptors evenly labeled with hydrogen isotopes].

A reaction of high-temperature solid-phase catalytic isotope exchange (HSCIE) was studied for the preparation of tritium- and deuterium-labeled ligands of glutamate and dopamine receptors. Tritium-labeled (5S,10R)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclopenten-5,10-imine ([G-(3)H]MK-801) and R(+)-7-hydroxy-N,N-di-n-propyl-2-aminotetraline ([G-(3)H]-7-OH-DPAT) were obtained with a specific activity of 210 and 120 Ci/mol, respectively. The isotopomeric distribution of deuterium-labeled ligands was studied using time-of-flight mass-spectrometer MX 5310 (ESI-o-TOF) with electrospray and orthogonal ion injection. Mean deuterium incorporation per ligand molecule was 11.09 and 3.21 atoms for [G-(2)H]MK-801 and [G-(2)H]-7-OH-DPAT, respectively. The isotope label was shown to be distributed all over the ligand molecule. The radioreceptor binding of tritium-labeled ligands [G-(3)H]MK-801 and [G-(3)H]-7-OH-DPAT was analyzed using the brain structure of Vistar rats. It was demonstrated that [G-(3)H]MK-801 specifically binds to hippocampus membranes with K(d) 8.3 +/- 1.4 nM, B(max) being 3345 +/- 300 fmol/mg protein. The [G-(3)H]-7-OH-DPAT ligand specifically binds to rat striatum membranes with K(d) 10.01 +/- 0.91 nM and B(max) 125 +/- 4.5 fmol/mg protein. It was concluded that the HSCIE reaction can be used for the preparation of highly tritium-labeled (+)-MK-801 and 7-OH-DPAT with retention of their physiological activities.

[Use of fuzzy models for predicting post-surgery complications in urological patients].

Use of modern information technologies in combination with fuzzy decision logic makes it possible to generate prognostic models for high-confidence determination of the risk of post-surgery complications in urological patients. Problems of use of automated decision support systems based on fuzzy models for improving the accuracy of prediction of post-surgery complications in urological patients are discussed.

[A new bromine-containing reagent for cysteine modification].

5-Bromo-2[(2-iodoacetyl)amino]benzenesulfonic acid (AIBSA), a reagent for modification of free of cysteine thiol groups in proteins and peptides, was synthesized. Rate constants of its interaction with thiol groups were determined. The presence of a bromine atom allows an easy identification of the AIBSA-labeled peptides in mass spectra due to the characteristic isotope distribution. The compound is stable in solution and under exposure to light.

[Arachidonoyl amino acids and arachidonoyl peptides: synthesis and properties].

N-Arachidonoyl (AA) derivatives of amino acids (glycine, phenylalanine, proline, valine, gamma-amino butyric acid (GABA), dihydroxyphenylalanine, tyrosine, tryptophan, and alanine) and peptides (Semax, MEHFPGP, and PGP) were synthesized in order to study the biological properties of acylamino acids. The mass spectra of all the compounds at atmospheric pressure electrospray ionization display the most intense peaks of protonated molecular ions; the detection limits for these compounds are 10 fmol per sample. AA-Gly showed the highest inhibitory activity toward fatty acid amide hydrolase from rat brain (IC50 6.5 microM) among all the acylamino acids studied. AA-Phe, AA-Tyr, and AA-GABA exhibited a weak but detectable inhibitory effect (IC50 55, 60, and 50 microM, respectively). The acylated amino acids themselves, except for AA-Gly, were stable to the hydrolysis by this enzyme. All the arachidonoylamino acids inhibited cabbage phospholipase D to various degrees; AA-GABA and AA-Phe proved to be the most active (IC50 20 and 27 microM, respectively). Attempts to detect the biosynthesis of AA-Tyr in homogenates of rat liver and nerve tissue showed no formation in vitro of either this acylamino acid or AA-dopamine and AA-Phe, the products of its metabolism. The highest contents of these metabolites were detected in liver homogenate and in the brain homogenate, respectively. Acylamino acids exert no cytotoxic effect toward the glioma C6 cells. It was shown that N-acylation of Semax with arachidonic acid results in enhancement of its hydrolytic stability and increases its affinity for the sites of specific binding in rat cerebellum membranes. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2006, vol. 32, no. 3; see also http://www.maik.ru.

[Mortality of able-bodied population in Saratov oblast and measures of its decreasing].

On the basis of analysis of health status of able-bodied population in Saratov oblast measures of enhancing health promotion of this population group are validated.