474 research outputs found
What is berry? Etymology of berries’ names
The main attention is paid to identifying the origin of words in Russian and English and comparing their etymolog
Controls on gut phosphatisation : the trilobites from the Weeks Formation Lagerstätte (Cambrian; Utah)
Despite being internal organs, digestive structures are frequently preserved in Cambrian Lagerstätten. However, the reasons for their fossilisation and their biological implications remain to be thoroughly explored. This is particularly true with arthropods--typically the most diverse fossilised organisms in Cambrian ecosystems--where digestive structures represent an as-yet underexploited alternative to appendage morphology for inferences on their biology. Here we describe the phosphatised digestive structures of three trilobite species from the Cambrian Weeks Formation Lagerstätte (Utah). Their exquisite, three-dimensional preservation reveals unique details on trilobite internal anatomy, such as the position of the mouth and the absence of a differentiated crop. In addition, the presence of paired pygidial organs of an unknown function is reported for the first time. This exceptional material enables exploration of the relationships between gut phosphatisation and the biology of organisms. Indeed, soft-tissue preservation is unusual in these fossils as it is restricted to the digestive structures, which indicates that the gut played a central role in its own phosphatisation. We hypothesize that the gut provided a microenvironment where special conditions could develop and harboured a source of phosphorus. The fact that gut phosphatization has almost exclusively been observed in arthropods could be explained by their uncommon ability to store ions (including phosphorous) in their digestive tissues. However, in some specimens from the Weeks Formation, the phosphatisation extends to the entire digestive system, suggesting that trilobites might have had some biological particularities not observed in modern arthropods. We speculate that one of them might have been an increased capacity for ion storage in the gut tissues, related to the moulting of their heavily-mineralised carapace
DNA Repair is Involved in Mechanism of Drug Sensibilization to Ionizing Radiation of Different Quality
It was shown that chemical compounds inhibit the process of cell recovery irradiated with sparsely and densely ionizing radiations. For both types of radiation, it was demonstrated that the irreversible component of radiation damage increases with increasing in drugs concentration, while the recovery constant, characterizing the probability of recovery per unit time, does not depend on the conditions of irradiation. This means that DNA repair is involved in mechanism of drug sensibilisation to ionizing radiation of different quality, which is associated with the formation of additional irreversible damage but not with damage of recovery processes as it was traditionally suggested. The obtained data indicate the prospects of chemical compounds using after irradiation of cells with ionizing radiations of different quality.
Keywords: ionizing radiation, survival, irreversible component, recovery constant, bleocin, doxorubicin, endoxan, fluorourozil, cisplatin
Estimation of the Severity of Experimental Tularemia against a Number of Morphometric Characteristics
Research objective consisted in the development of a unified approach to the evaluation of severity of experimental tularemia disease based on the morphometric analysis. Experimental tularemia infection was morbidized in Guinea pigs, both female and male, using subcutaneous inoculation with virulent tularemia microbe cultures. Subsequent to the results of morphometric analysis, selected was a range of indicators characterizing intensiveness of dystrophy, necrobiotic and necrotic processes, infiltrate changes within cells and tissues of the infected animals to fullest extent, and reflecting a life-support system functioning state adequately. Thus, application of quantitative counting to distinguish the changes in experimental animals, while modeling specific infectious process, allowed for standardization and verification of severity evaluation approach and facilitated increase in quality of experimental investigations
Microswarm structure of a meteoric complex beyond an ecliptic plane
The purpose of this work is to determine maximum allowed numbers of measurements used in the discrete solution, at which probability to detect a false microshower will be rather small, and to find out how this number is connected to the solution accuracy and how it corresponds with productivity of the meteoric radar. We have advanced a quasi-thomography method in the solution of a problem of determination of meteor radiant distributions on a celestial sphere based on the data of radar goniometer measurements. We have tried to find out, how the stable structures of radiants prolated along an elongation angle from apex in the course of the year vary, how they are correlated in time and whether they will be repeated from one year to other year
Antioxidative Activity of Ferrocenes Bearing 2,6-Di-Tert-Butylphenol Moieties
The antioxidative activity of ferrocenes bearing either 2,6-di-tert-butylphenol or phenyl groups has been compared using DPPH (1,1-diphenyl-2-picrylhydrazyl) test and in the study of the in vitro impact on lipid peroxidation in rat brain homogenate and on some characteristics of rat liver mitochondria. The results of DPPH test at 20°C show that the activity depends strongly upon the presence of phenolic group but is improved by the influence of ferrocenyl fragment. The activity of N-(3,5-di-tert-butyl-4-hydroxyphenyl)iminomethylferrocene (1), for instance, was 88.4%, which was higher than the activity of a known antioxidant 2,6-di-tert-butyl-4-methylphenol (BHT) (48.5%), whereas the activity of N-phenyl-iminomethylferrocene 2 was almost negligible −2.9%. The data obtained demonstrate that the compounds with 2,6-di-tert-butylphenol moiety are significantly more active than the corresponding phenyl analogues in the in vitro study of lipid peroxidation in rat brain homogenate. Ferrocene 1 performs a promising behavior as an antioxidant and inhibits the calcium-dependent swelling of mitochondria. These results allow us to propose the potential cytoprotective (neuroprotective) effect of ditopic compounds containing antioxidant 2,6-di-tert-butylphenol group and redox active ferrocene fragment
Associations of meteor microshowers or as the Kazan radar "SEES" radiants on northern celestial hemisphere
The discrete quasitomographic method of the analysis of the interferometric data of meteor radar gives us the possibility of measuring coordinates and velocities of very weak meteor showers with a 2 × 2 square degree resolution on the celestial sphere. The minimal rate of the meteors in each microstream is five meteors per day. At such sensitivity, basic distinctions between irregularities of the sporadic background and meteor streams vanish. More than 1000 of the detected microshowers per month are associated with a combination of (a) the large known meteor showers, (b) the weaker known meteor showers and (c) till now unknown associations of microshowers. All microshowers regardless of association have the identical velocities, limited areas of radiation and near simultaneity of their acting dates. The results are compiled as maps of radiant distribution and average velocities of microstreams for different months. From these it is possible to see how the microshower activity for various discrete sites on the celestial sphere correlate with the behavior of the well-known meteor streams and thus to infer the orbital properties of the different microstream configurations. © Springer Science+Business Media, Inc. 2005
Дія антимікробних препаратів і світлодіодного випромінювання на добові біоплівки S. aureus та E. coli
Estimating the results of the antimicrobial action and the LED radiation on diurnal S. aureus and E. coli biofilms it has been found that under the complex effects using optical emission of the orange spectrum and β-lactam antimicrobial drugs the density of biofilms was 1.5 times higher than the control values; under the action of the drug from the group of fluoroquinolones levofloxacin and the orange LED emission spectrum the density of daily S. aureus biofilm was 42.8 times reduced, and E. coli decreased by 18.9 times compared to the control. When determining the impact of the green radiation spectrum together with β-lactam antimicrobial drugs on daily biofilms of multiresistant strains there is inhibition of the density of isolates biofilm of both S. aureus and E. coli compared to the control. In a complex application of levofloxacin and the green LED emission spectrum the destruction of daily biofilms of multiresistant isolates of S. aureus by 2.4 times and E. coli by 3.1 times has been determined compared to the control. The similar results have been reported in determining the ability of irradiated planktonic cells to form the secondary biofilms: the lowest density of the secondary biofilm is registered in application of the optical radiation of the violet spectrum in combination with levofloxacin: the density of the secondary S. aureus biofilm reduced by 52.4, and the density of the E. coli biofilm reduced by 39.3 times compared to the control. As a result of this study the possibility of using the incoherent optical radiation of the violet spectrum with levofloxacin, which is a photosensitizer and contributes to decrease in the proliferative activity and the ability to form biofilms of multiresistant isolates of S. aureus and E. coli and increase their antibiotics resistance, in the treatment of inflammatory processes has been substantiated.Оценивая результаты действия противомикробных препаратов и светодиодного излучения на суточные биопленки S. aureus и E. coli, было установлено, что под комплексным воздействием с применением оптического излучения оранжевого спектра и β-лактамных противомикробных препаратов плотность биопленок была в 1,5 раза выше контрольных значений, препарата из группы фторхинолонов левофлоксацина и светодиодного излучения оранжевого спектра наблюдалось снижение плотности суточной биопленки S. aureus в 42,8 раза; а E. coli – в 18,9 раза по сравнению с контролем. При определении влияния излучения зеленого спектра вместе с β-лактамными антимикробными препаратами на суточные биопленки полирезистентных штаммов наблюдается угнетение плотности биопленки изолятов как S. aureus, так и E. coli по сравнению с контролем. А при комплексном применении левофлоксацина и светодиодного излучения зеленого спектра установлено разрушение суточных биопленок полирезистентных изолятов S. aureus в 2,4 раза, а E. coli в 3,1 раза по сравнению с контролем. Аналогичные результаты были зафиксированы при определении способности облученных планктонных клеток образовывать вторичные биопленки: наименьшая плотность вторичной биопленки зарегистрирована при применении оптического излучения фиолетового спектра комплексно с левофлоксацином: плотность вторичной биопленки S.aureus снижена в 52,4 и в 39,3 раза – снижена плотность вторичной биопленки E.coli сравнению с контролем. В результате данного исследования обоснована возможность применения в комплексной терапии гнойно-воспалительных процессов низкоинтенсивного некогерентного оптического излучения фиолетового спектра с левофлоксацином, который является фотосенсибилизатором и способствует подавлению пролиферативной активности и способности к формированию биопленок полирезистентных изолятов S. aureus и E. coli и повышению их антибиотикочувствительности.Оцінюючи результати щодо визначення дії антимікробних препаратів і світлодіодного випромінювання на добові біоплівки S. aureus і E. coli було встановлено, що під комплексним впливом із застосуванням оптичного випромінювання помаранчевого спектра та β-лактамних антимікробних препаратів щільність біоплівок була у 1,5 рази вища за контрольні значення, препарату з групи фторхінолонів левофлоксацину і світлодіодного випромінювання помаранчевого спектра зниження щільності добової біоплівки S. aureus у 42,8 рази а E. coli – у 18,9 рази порівняно з контролем. При визначенні впливу випромінювання зеленого спектра разом з β-лактамними антимікробними препаратами на добові біоплівки полірезистентних штамів спостерігається пригнічення щільності біоплівки ізолятів як S. aureus, так і E. coli порівняно з контролем. А при комплексному застосуванні левофлоксацину і світлодіодного випромінювання зеленого спектра встановлено руйнування добових біоплівок полірезистентних ізолятів S. aureus у 2,4 рази, а E. coli у 3,1 рази порівняно з контролем. Застосування антимікробних препаратів і світлодіодного випромінювання фіолетового спектра призвело до зниження щільності добових біоплівок S. aureus у 17,4 рази при застосуванні амоксиклаву, у 13,4 рази при застосуванні цефтриаксону та у 42,8 рази в комплексі з левофлоксацином. Аналогічні результати були зафіксовані при визначенні здатності опромінених планктонних клітин утворювати вторинні біоплівки: найменша щільність вторинної біоплівки зареєстрована при застосуванні оптичного випромінювання фіолетового спектра комплексно з левофлоксацином: щільність вторинної біоплівки S. aureus знижена у 52,4 та у 39,3 рази – знижена щільність вторинної біоплівки E. coli порівняно з контролем. У результаті цього дослідження обґрунтовано можливість застосування у комплексній терапії гнійно-запальних процесів низькоінтенсивного некогерентного оптичного випромінювання фіолетового спектра з левофлоксацином, який є фотосенсибілізатором та сприяє пригніченню проліферативної активності і здатності до формування біоплівок полірезистентних ізолятів S. aureus та E. coli і підвищенню їх антибіотикочутливості
A nomogram for predicting mortality in patients with COVID-19-associated acute respiratory distress syndrome treated with veno-venous extracorporeal membrane oxygenation
The objective was to develop a predictive model for assessing the risk of hospital mortality in patients with COVID-19-associated acute respiratory distress syndrome (ARDS) treated with veno-venous extracorporeal membrane oxygenation (VV-ECMO).Materials and methods. We carried out the analysis of case histories of 123 patients treated in the ICU № 7 of the Moscow City Clinical Hospital 52 during the COVID-19 pandemic period. All patients were treated with the VV-ECMO for COVID-19-associated ARDS according to current indications. We analyzed the characteristics potentially associated with mortality, after which we performed statistical analysis, on the basis of which we created the predictive model.Results. The overall-mortality rate was 87% (107/123). Independent predictors of death in patients with COVID-19 treated with the VV-ECMO were the maximum VV-ECMO blood flow rate, the period from the onset of the disease to mechanical ventilation, P/F prior to the VV-ECMO initiation and the fact of septic shock development during VV-ECMO. The quality of the prognostic model: AUC = 0.952 [0.909‒0.995], p < 0.001.Conclusions. The nomogram to assess the risk of death in patients with COVID-19 treated with the VV ECMO has been developed. It includes the assessment of the maximum VV-ECMO blood flow rate, the period from the onset of the disease to mechanical ventilation, P/F prior to the VV-ECMO initiation and the fact of septic shock development during VV-ECMO
Migraine and sleep disorders: a systematic review
Migraine and sleep disorders are common and often burdensome chronic conditions with a high prevalence in the general population, and with considerable socio-economic impact and costs. The existence of a relationship between migraine and sleep disorders has been recognized from centuries by clinicians and epidemiological studies. Nevertheless, the exact nature of this association, the underlying mechanisms and interactions are complex and not completely understood. Recent biochemical and functional imaging studies identified central nervous system structures and neurotransmitters involved in the pathophysiology of migraine and also important for the regulation of normal sleep architecture, suggesting a possible causative role, in the pathogenesis of both disorders, of a dysregulation in these common nervous system pathways. This systematic review summarizes the existing data on migraine and sleep disorders with the aim to evaluate the existence of a causal relationship and to assess the presence of influencing factors. The identification of specific sleep disorders associated with migraine should induce clinicians to systematically assess their presence in migraine patients and to adopt combined treatment strategies
- …
