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Ommochromes are screening and antioxidant pigments in the compound eyes of invertebrates and fulfil the functions of light filtration, light absorption, and antioxidant defense. We report here the first observation that ommochromes display antiglycation activity in vitro. Ommochromes were prepared from the eyes of insects of three different families: Strationyidae, Sphingidae, and Acrididae. All the ommochromes studied were found to inhibit the reaction forming fluorescent serum albumin modification products in the presence of high fructose concentrations (fructosylation). Ommochromes from the eyes of the black soldier fly (Hermetia illucens) were the most effective fructosylation inhibitors. Ommochromes oxidized with hydrogen peroxide produced no inhibitory action in relation to glycation. Our results are of interest both for understanding the biological role of ommochromes in invertebrates, in particular for clarifying their influence on oxidative modification of the proteins of the retinular and pigment cells of ommatidia, and for using them to create pharmacological agents for the treatment and prevention of pathology associated with the development of metabolic syndrome.

Lipofuscin granules accumulate in the retinal pigment epithelium (RPE) with age, especially in patients with visual diseases, including progressive age-related macular degeneration (AMD). Bisretinoids and their photooxidation and photodegradation products are major sources of lipofuscin granule fluorescence. The present study focused on examining the fluorescence decay characteristics of bisretinoid photooxidation and photodegradation products to evaluate the connection between fluorescence lifetime and spectral characteristics of target fluorophore groups. The primary objective of the study was to apply experimental spectral analysis results of lipofuscin granule fluorescence properties to interpretation of fluorescence lifetime imaging ophthalmoscopy data. Fluorescence analysis of the lipofuscin granule fluorophores in RPE collected from cadaver eyes was performed. The fluorescence lifetimes were measured by picosecond-resolved time correlated single photon counting technique. A global analytical method was applied to analyze data sets. The photooxidation and photodegradation products of bisretinoids exhibited a longer fluorescence lifetime (average value approximately 6 ns) and a shorter wavelength maximum (530–580 nm). Further, these products significantly contributed (more than 30%), to total fluorescence compared to the other fluorophores in lipofuscin granules. Thus, the contribution of oxidized lipofuscin bisretinoids to autofluorescence decay kinetics is an important characteristic for fluorescence lifetime imaging microscopy data analysis. The higher average fluorescence lifetime in AMD eyes was likely due to the higher abundance of oxidized bisretinoids compared with non-oxidized bisretinoids. Because higher level of oxidized bisretinoids is indicative of pathological processes in the retina and RPE, the present findings have the potential to improve fluorescence lifetime imaging approaches for early diagnosis of degenerative processes in the retina and RPE.

PURPOSE: The aim of this work is the determination of quantitative diagnostic criteria based on the spectral characteristics of fundus autofluorescence to detect early stages of degeneration in the retina and retinal pigment epithelium (RPE). METHODS: RPE cell suspension samples were obtained from the cadaver eyes with and without signs of age-related macular degeneration (AMD). Fluorescence analysis at an excitation wavelength of 488 nm was performed. The fluorescence lifetimes of lipofuscin-granule fluorophores were measured by counting time-correlated photon method. RESULTS: Comparative analysis of fluorescence spectra of RPE cell suspensions from the cadaver eyes with and without signs of AMD showed a significant difference in fluorescence intensity at 530–580 nm in response to fluorescence excitation at 488 nm. It was notably higher in eyes with visual pathology than in normal eyes regardless of the age of the eye donor. Measurements of fluorescence lifetimes of lipofuscin fluorophores showed that the contribution of photooxidation and photodegradation products of bisretinoids to the total fluorescence at 530–580 nm of RPE cell suspensions was greater in eyes with visual pathology than in normal eyes. CONCLUSION: Because photooxidation and photodegradation products of bisretinoids are markers of photodestructive processes, which can cause RPE cell death and initiate degenerative processes in the retina, quantitative determination of increases in these bisretinoid products in lipofuscin granules may be used to establish quantitative diagnostic criteria for degenerative processes in the retina and RPE.

Hydroxyapatite was synthesized in conditions of mechanoacoustic treatment of an aqueous reaction mixture consisting of ammonium hydrogen phosphate and calcium nitrate using a commercially available rotary pulsation apparatus. Mechanoacoustic treatment of the reaction mixture was found to lead to the formation of nanosized hydroxyapatite particles with a predominant mean diameter of about 20 nm. Purification of technical hydroxyapatite to remove traces of ammonium nitrate by thermal processing at 350°C is proposed. The crystalline phase of hydroxyapatite was found not to be dominant in the structure. The porosity of hydroxyapatite amounted to about 75% with a mean pore diameter of 2.8 × 103 nm. Thermal processing of hydroxyapatite in aqueous medium was found to yield a paste-like form. Hydroxyapatite paste had no cytotoxicity and did not prevent cell adhesion, though it almost completely inhibited cell spreading.

The behavior of detonation and plasma coatings in conditions of dry friction against titanium alloy OT-4 and stainless steel 07Kh16N6 has been studied. The detonation coatings show significantly better tribological properties than the plasma coatings. This is probably due to the presence of aluminum and titanium nitrides possessing high wear resistance in the detonation coatings. Oxidation of the plasma and detonation coatings at a temperature of 900°C in air has been examined. The detonation and plasma coatings exhibit greater oxidation resistance than uncoated titanium alloy VT-16.

Fundus autofluorescence mostly originates from bisretinoid fluorophores in lipofuscin granules, which accumulate in retinal-pigment-epithelium cells with age. The dynamics of accumulation, photo-oxidation, and photodegradation of bisretinoids during aging or in the presence of pathology have been insufficiently investigated. Changes in spectral properties and composition of human lipofuscin-granule fluorophores with age and pathology have now been investigated by a high-performance liquid chromatography method using spectrophotometric and fluorescent detectors connected in series. It was found that: (i) N-retinylidene-N-retinylethanolamine (A2E) fluorescence intensity is not predominant in the chloroform extract of human-cadaver-eye retinal pigment epithelium studied; bisretinoid photo-oxidation and photodegradation products have much higher fluorescent properties; (ii) the relative emission maximum in the fluorescence spectrum of suspended retinal-pigment-epithelium cells obtained from an individual human-cadaver eye without pathology is irrespective of donor age and falls within the range 575 ± 15 nm; in two cadaver eyes with signs of age-related macular degeneration, emission maxima were shifted by 23-36 nm towards the shortwave region; and (iii) the ratio of bisretinoid photo-oxidation and photodegradation products to unoxidized bisretinoids in the chloroform extract of cadaver-eye retinal pigment epithelium increases with donor age, from 0.69 ± 0.03 to 1.32 ± 0.04. The differences in fluorescence properties between chloroform extracts obtained from cadaver eyes with and without signs of age-related macular degeneration could be used to increase the potential of fundus autofluorescence imaging as a noninvasive diagnostic method.

Visible light-induced changes in fluorescence characteristics of lipofuscin granules (LG) isolated from retinal pigment epithelium of human cadaver eyes are compared with the analogous age-related changes and correlated with the content and photooxidation of LG main fluorophore, A2E. We used HPLC to examine changes of LG fluorophore composition with donor age, as well as before and after visible-light irradiation (the latter HPLC tests were also done with synthetic A2E). Visible light induces oxidation of LG fluorophores. As a result, their fluorescence characteristics change: the emission spectrum is blue-shifted by 25–40 nm. The observed age-dependent changes in the relative content of LG fluorophores and their oxidized derivatives were qualitatively similar with those caused by irradiation. To improve the accuracy of a new noninvasive diagnostic method, fundus autofluorescence imaging, it is important to know the ratio of nonoxidized and oxidized fluorophore derivatives depending on age and eye pathology.

The paper examines the phase formation of detonation coatings sprayed from mechanically alloyed Ti–50 Al–25 B powder. It is shown that coatings with different phase compositions and functional properties can be consolidated from this activated powder by varying process conditions (including gas composition during detonation spraying). Three types of composite coatings with different structures are obtained: TiB and TiB2 inclusions are distributed in an intermetallic matrix (Al3Ti, γ-TiAl); inclusions of oxides and oxynitrides are additionally present in the same structure; inclusions of borides, Al, and Ti are distributed in a mixture of intermetallic and nitride (TiN, AlN) phases.

The role of the kidneys in endotoxin aggression (EA) and the involvement of EA in disturbance of hemostasis were shown in 33 children with congenital urological pathology. With a progressive decrease in the accumulative-excretory function of the kidneys, compensated chronic EA became subcompensated or noncompensated with a pronounced clinical manifestation: fever, exacerbation of chronic pyelonephritis, an expanded form of the disseminated intravascular coagulation (DIC) III syndrome, and macrohematuria. Preoperative correction of antiendotoxin immunity and hemostasis and improvement of urine passage prevented bleeding and other postoperative complications.

Collagen induced the synthesis of collagenolytic enzymes in the culture of Aspergillus flavus. Enzyme activity of the culture increased during storage and passage on a medium with this inductor. We developed a method for isolation and purification of collagenolytic enzymes and obtained two electrophoretically homogenous enzyme preparations belonging to neutral thermolabile collagenolytic metalloproteinases.

The authors examined students of specialized secondary education institutions of Syktyvkar during a three-year-long period. Some morphofunctional indices are worse in them than in similar cohorts in Central Russia. The unfavorable environmental situation impaired tolerance to hypoxemia, cardiac rhythm regulation, central hemodynamics, and balance of autonomic processes and affected dynamics of the physiological status of the body during social adaptation to learning.

A new composition for electrovacuum lead glass with a 20 wt. % PbO has been synthesized. The system of loading the charge and glass scrap into a furnace and a new system of tube shaping are described. The effect of the moisture content of the charge and the temperature on volatilization of PbO, Na2O, and K2O is investigated. It is shown that an artificially formed protective layer on the surfaces of discharge channels considerably reduces the volatilization of PbO, Na2O, and K2O from the liquid glass. Practical recommendations are presented.

A unified equation of state of freezant R23 is obtained that adequately describes a thermodynamic surface both in the region of low densities and pressures and in the vicinity of a critical point.

Individual sensitivity to nickel compounds was studied in workers employed in nickel industry. The mutagen sensitivity was inferred from the number of sister chromatid exchanges (SCEs), which was used to characterize the structural alterations of the chromosomes in workers' lymphocytes before and after administration of retinol for a month. The SCE number decreased after retinol administration in nine out of eleven workers.

The critical speed for bending-torsional flutter can be increased by decreasing the unbalance of the airfoil [i], i .e. , by moving the center of mass of each spanwise element closer to the stiffness axis. This can be achieved by adding balance masses ahead of the stiffness axis or even by adding a single concentrated mass at a certain section of the airfoil. The size and situation of the mass have a definite influence on the magnitude of the critical flutter speed. In the usual design calculation for bending-torsional flutter of an airfoil by the Bubnov-Galerkin method [I], an equivalent two-degree-of-freedom system is introduced. The va r i ab l e s in this s y s t e m a r e two "gene r a l i z e d " coord ina tes c o r r e s p o n d i n g to two p r e s c r i b e d modes : bending and to r s ion of the a i r fo i l . The p a r a m e t e r s of the "equiva len t" s y s t e m a r e the values of the fol lowing quant i t ies : the mass of the a i r fo i l , its m o ment of ine r t i a , its bending and to r s iona l s t i f fness , and the s ta t ic m o m e n t d e s c r i b i n g the ine r t i a l coupl ing between bending and to r s ion . Acco rd ing to the Bubnov-Ga le rk in method, the ef fec t of the balance m a s s on the c r i t i c a l f lu t t e r speed is as fol lows. The ins ta l la t ion of a ba lance m a s s changes the p a r a m e t e r s of the "equ iva len t " t w o d e g r e e o f f r e e d o m sys t em, i nc r ea s ing the e f fec t ive m a s s and momen t of iner t ia and d e c r e a s i n g the ef fec t ive coef f ic ien t of i n e r t ia coupling between the " g e n e r a l i z e d " bending and t o r s ional coord ina te s . The d e c r e a s e in coupling leads to a d e c r e a s e in the amount of e n e r g y f r o m the a i r flow, and hence the c r i t i c a l f lu t t e r speed is d e c r e a s e d . A method of de t e rmin ing the c r i t i c a l f lu t t e r speed of an a i r fo i l based on the d i r e c t solut ion of the equations for bend ingto r s iona l v ib ra t ions by means of an analog compute r was d e s c r i b e d in [2]. This method makes no assumpt ions about the types of v ibra t ion . The a c c u r a c y of the solut ion depends only on the extent to which the equat ions d e s c r i b e an actual wing, the a c c u r a c y in spec i fy ing the p a r a m e t e r s and ae rodynamic f o r c e s , and the machine e r r o r s . This method is used below to det e r m i n e the c r i t i c a l f lu t t e r speed, toge the r with the f requency and type of the f lu t t e r modes of an a i r fo i l with ba lance m a s s . The r e s u l t s obtained a r e c o m p a r e d with the c o r r e s p o n d i n g r e s u l t s given by the BubnovGalerk in method. It is shown that for the given example (also c o n s i d e r e d in [2]) of a un i fo rm a i r fo i l t h e r e a r e d i s c r e p a n c i e s be tween the two methods , at l e a s t for ce r t a in b a l a n c e r p a r a m e t e r s . 1. The equat ions for the bend ing to r s iona l v i b r a tion of a long un i fo rm a i r fo i l a r e [1]

In acute and chronic experiments staged on cats and rabbits a study was made of the role played by various portions of the brain in the reaction of respiration to aminazine. In administration of this preparation in a dose of 2–3 mg/kg to cats and in a dose of 8–10 mg/kg to rabbits no significant shifts occurred in the frequency and nature of respiratory movements. The use of hypnotics, acting as a depressive agent on the brain cortex, did not change the reaction of respiration to aminazine. In decerabrated anaimals, aminazine injection led to marked respiratory disturbances. Such animals often perish, the cause of death being repsiratory arrest. Evidently, weakly pronounced respiratory reactions following aminazine administration in intact animals were the result of considerable compensatory capacities of the higher portions of the brain in respiratory regulation.

Cardiovascular and respiratory disturbances occuring in chlorpromazine administration are more pronounced in decerebrated animals than in the intact ones. Antagonistic relationships of chlorpromazine and adrenaline (according to the indices of arterial pressure and respiration) developed in decerebrated animals without significant differences from the animals with an intact central nervous system.