Unsteady flow characteristics in the near-wake of a two-dimensional obstacle

The influence of the characteristics of the boundary layer separation on the formation of vortices and alternate paths in the wake of a bidimensional obstacle at high Reynolds numbers was studied by ultra fast visualization system. It is shown that there are alternate paths for laminar and turbulent flows, with similar flow characteristics. It is found that emission of vortices does not change substantially when the flow passes from laminar to turbulent. A film with a time scale change of 10,000 times illustrates some of the discussed phenomena

МІКРОБІОМ У ФІЗІОЛОГІЇ ЛЮДИНИ

Basic facts concerning human microbiome. Long-term coevolution of the human organism and microbe community has led to the formation of an additional anatomical structure in the human body that was named microbiome. This unique microbe structure has a complex organ organization that functions in mutual consent with all other human organs and systems. Localization of microbiome in the human body. All biotopes of the human body (oral cavity, hair, nose, ears, urogenital system, skin, eyes, gastrointestinal tract, and bronchopulmonary system) have their own unique and specific microbe complex that consists of specialized microbes with various functions. Besides, all these local microbiomes are in continuous interactions with each other and with macroorganism making the united superorganism system. Microbiome functional activity. Microbiome takes active part in realization of a wide spectrum of vitally important physiological processes, including energetic homeostasis and metabolism, synthesis of vitamins and other significant nutrients, endocrine signaling, preventing pathogen colonization, regulation of immune function, metabolism of xenobiotics, toxins, carcinogens and other harmful substances. Most these functions are closely connected and tightly implicated with human physiology. Changes of microbiome during ontogenesis. Microbiome formation begins long before childbirth and continues 2–3 years after it. In the course of the organism maturation and aging, microbiome changes appreciably. Microbiome improvement at all stages of human life is of the utmost importance for improving health of all age group population. Microbiome damages in etiology of human diseases. Numerous investigations showed that microbiome changes are associated with a large spectrum of gastrointestinal and systemic diseases, including inflammatory intestinal diseases, asthma, obesity, metabolic syndrome, cardiovascular pathology, autoimmune, neurobehavioral and many other diseases. Modern approaches to microbiome improvement. To date, many different methods of therapeutic influence on microbiome have been proposed: changing diet, applying probiotics, prebiotics or their complexes (synbiotics), using functional foodstuffs, carrying out fecal transplantation etc. The authors propose universal approaches to prophylaxes of microbiome disturbances and its reversal in people of different age categories; its efficiency has been convincingly demonstrated in clinics.Загальні відомості про мікробіом людини. В результаті тривалої коеволюції людини з мікробним співтовариством сконструйовано і вдосконалено додаткову анатомічну структуру тіла людини, яка отримала назву мікробіом. Цей унікальний мікробний орган має складну органну структуру, функціонуючу у взаємній згоді з усіма іншими органами та системами людини. Локалізація мікробіому в тілі людини. Всі біотопи тіла людини (ротова порожнина, волосся, ніс, вуха, сечостатеві шляхи, шкіра, очі, шлунково-кишковий тракт, бронхо-легенева системи) містять свій власний унікальний специфічний складний мікробний комплекс, що складається зі спеціалізованих мікробів з різними функціями. При цьому всі локальні мікробіоми перебувають у постійній взаємодії між собою і з макроорганізмом, утворюючи єдину надорганізмову систему. Функціональна активність мікробіому. Мікробіом бере активну участь в реалізації широкого спектра життєво важливих фізіологічних процесів, включаючи енергетичний гомеостаз і метаболізм, синтез вітамінів та інших важливих нутрієнтів, ендокринну сигналізацію, регуляцію імунної функції, метаболізм ксенобіотиків, токсинів, канцерогенів та інших шкідливих сполук, запобігає колонізації патогенами. Більшість цих функцій взаємопов’язана та тісно переплетена з фізіологією людини. Зміни мікробіому в онтогенезі. Процес формування мікробіому починається задовго до народження дитини і продовжується 2-3 роки після народження. У міру дорослішання та старіння організму спостерігаються помітні зміни мікробіому. Підтримка мікробіому на всіх етапах життя людини має величезне значення для поліпшення здоров’я населення всіх вікових категорій. Місце мікробіомних порушень в етіології захворювань людини. Багатьма дослідженнями показано, що зміни в мікробіомі асоціюються з широким спектром шлунково-кишкових і системних захворювань, включаючи запальні хвороби кишечнику, астму, ожиріння, метаболічний синдром, серцево-судинну патологію, автоімунні, нейроповедінкові, та з багатьма іншими хворобами. Сучасні підходи до оздоровлення мікробіому. Сьогодні пропонуються різні методи терапевтичного впливу на мікробіом: зміна дієти, застосування пробіотиків, пребіотиків або їх комплексів (синбіотиків), продуктів функціонального харчування, ентеросорбентів, проведення фекальної трансплантації та ін. Авторами запропоновані універсальні підходи до профілактики мікробіомних порушень та їх усунення в осіб різних вікових категорій, ефективність яких переконливо доведена клінікою

The genetic basis of multiple sclerosis: a model for MS susceptibility

<p>Abstact</p> <p>Background</p> <p>MS-pathogenesis is known to involve both multiple environmental events, and several independent genetic risk-factors.</p> <p>Methods</p> <p>A model of susceptibility is developed and a mathematical analysis undertaken to elucidate the nature of genetic susceptibility to MS and to understand the constraints that are placed on the genetic basis of MS, both by the known epidemiological facts of this disease and by the known frequency of the HLA DRB1*1501 allele in the general populations of northern Europe and North America.</p> <p>Results</p> <p>For the large majority of cases (possibly all), MS develops, in part, because an individual is genetically susceptible. Nevertheless, 2.2% or less of the general population is genetically susceptible. Moreover, from the model, the number of susceptibility-loci that need to be in a "susceptible allelic state" to produce MS-susceptibility is small (11-18), whereas the total number of such susceptibility-loci is large (50-200), and their "frequency of susceptibility" is low (i.e., ≤ 0.12). The optimal solution to the model equations (which occurs when 80% of the loci are recessive) predicts the epidemiological data quite closely.</p> <p>Conclusions</p> <p>The model suggests that combinations of only a small number of genetic loci in a "susceptible allelic state" produce MS-susceptibility. Nevertheless, genome-wide associations studies with hundreds of thousands of SNPs, are plagued by both false-positive and false-negative identifications and, consequently, emphasis has been rightly placed on the replicability of findings. Nevertheless, because genome-wide screens don't distinguish between true susceptibility-loci and disease-modifying-loci, and because only true susceptibility-loci are constrained by the model, unraveling the two will not be possible using this approach.</p> <p>The model also suggests that HLA DRB1 may not be as uniquely important for MS-susceptibility as currently believed. Thus, this allele is only one among a hundred or more loci involved in MS susceptibility. Even though the "frequency of susceptibility" at the HLA DRB1 locus is four-fold that of other loci, the penetrance of those susceptible genotypes that include this allele is no different from those that don't. Also, almost 50% of genetically-susceptible individuals, lack this allele. Moreover, of those who have it, only a small fraction (≤ 5.2%) are even susceptible to getting MS.</p

The Inheritance of Resistance Alleles in Multiple Sclerosis

Multiple sclerosis (MS) is a complex trait in which alleles at or near the class II loci HLA-DRB1 and HLA-DQB1 contribute significantly to genetic risk. HLA-DRB1*15 and HLA-DRB1*17-bearing haplotypes and interactions at the HLA-DRB1 locus increase risk of MS but it has taken large samples to identify resistance HLA-DRB1 alleles. In this investigation of 7,093 individuals from 1,432 MS families, we have assessed the validity, mode of inheritance, associated genotypes, and the interactions of HLA-DRB1 resistance alleles. HLA-DRB1*14-, HLA-DRB1*11-, HLA-DRB1*01-, and HLA-DRB1*10-bearing haplotypes are protective overall but they appear to operate by different mechanisms. The first type of resistance allele is characterised by HLA-DRB1*14 and HLA-DRB1*11. Each shows a multiplicative mode of inheritance indicating a broadly acting suppression of risk, but a different degree of protection. In contrast, a second type is exemplified by HLA-DRB1*10 and HLA-DRB1*01. These alleles are significantly protective when they interact specifically in trans with HLA-DRB1*15-bearing haplotypes. HLA-DRB1*01 and HLA-DRB1*10 do not interact with HLA-DRB1*17, implying that several mechanisms may be operative in major histocompatibility complex–associated MS susceptibility, perhaps analogous to the resistance alleles. There are major practical implications for risk and for the exploration of mechanisms in animal models. Restriction of antigen presentation by HLA-DRB1*15 seems an improbably simple mechanism of major histocompatibility complex–associated susceptibility

Active oceanic spreading in the northern north Fiji basin : results of the NOFI cruise of R/V l'Atalante (Newstarmer project)

The South Pandora and the Tripartite Ridges are active spreading centers located in the northern part of the North Fiji Basin. These spreading centers were surveyed over a distance of 750 km during the NOFI cruise of R/V L'Atalante (August-September 1994) which was conducted in the frame of the french-japanese Newstarmer cooperation project. SIMRAD EM12-dual full coverage swath bathymetric and imagery data as well as airgun 6-channel seismic, magnetics and gravity profiles were recorded along an off-axis from 170°40'E to 178°E. Dredging and piston coring were also performed along and off-axis. The axial domain of the South Pandora Ridge is divided into 5 first-order segments characterized by contrasted morphologies. The average width of the active domain is 20 km and corresponds either to bathymetric highs or to deep elongated grabens. The bathymetric highs are volcanic constructions, locally faulted and rifted, which can obstruct totally the axial valley. The grabens show the typical morphology of slow spreading axes, with two steep walls flanking a deep axial valley. Elongated lateral ridges may be present on both sides of the grabens. Numerous volcanoes, up to several kilometers in diameter, occur on both flanks of the South Pandora Ridge. The Tripartite Ridge consists of three main segments showing a sigmoid shape. Major changes in the direction of the active zones are observed at the segment discontinuities. These discontinuities show various geometrical patterns which suggest complex transform relay zones. Preliminary analysis of seismic reflection profiles suggest that the Tripartite Ridge is a very young feature which propagates into an older oceanic domain characterized by a significant sedimentary cover. By contrast, a very thin to absent sedimentary cover is observed about 100 km on both flanks of the South Pandora Ridge active axis. The magnetic anomaly profiles give evidence of long and continuous lineations, parallel to the South Pandora Ridge spreading axis. (Résumé d'auteur

Influence of gel bentonite on physiological indicators of the white laboratory mice.

The evaluation of the effect of lifelong usage of sodium form of gel bentonite on some physiological parameters of mice (body weight, feed and water intake, general condition, change in coordination of movements, state of wool, fertility and mortality) was performed on 110 white laboratory mice (BALB / c line). This experimental study was carried out in two replicates. To accomplish this task, the mice were divided into two groups: control – the animals were on a standard diet, and experimental – they used water with the addition of sodium form of bentonite gel (0.5-1%). It was found that prolonged intake of bentonite gel by laboratory animals neither led to an excessive increase in their weight (the weight gain of the experimental group did not differ statistically significantly from the control group, p≤0.05), nor did it cause acute or chronic intoxication. It is also shown that the constant use of bentonite has a positive effect on the organism of experimental mice, which is expressed in the decrease of animal mortality, increase of life expectancy and pronounced positive effect on fertility functions (increase in the number of offspring). Based on the obtained data it can be assumed that the continuous intake of bentonite by the animal organism is one of the factors of their microbiome improvement, which affects on a plenty of physiological functions, including animals reproduction. It is possible that smectite sorbents also enrich the body of mice by certain essential mineral elements (silicon, etc.) and has cytomucoprotective properties concerning the mucous membranes of the macroorganism

Influence of gel bentonite on physiological indicators of the white laboratory mice.

The evaluation of the effect of lifelong usage of sodium form of gel bentonite on some physiological parameters of mice (body weight, feed and water intake, general condition, change in coordination of movements, state of wool, fertility and mortality) was performed on 110 white laboratory mice (BALB / c line). This experimental study was carried out in two replicates. To accomplish this task, the mice were divided into two groups: control – the animals were on a standard diet, and experimental – they used water with the addition of sodium form of bentonite gel (0.5-1%). It was found that prolonged intake of bentonite gel by laboratory animals neither led to an excessive increase in their weight (the weight gain of the experimental group did not differ statistically significantly from the control group, p≤0.05), nor did it cause acute or chronic intoxication. It is also shown that the constant use of bentonite has a positive effect on the organism of experimental mice, which is expressed in the decrease of animal mortality, increase of life expectancy and pronounced positive effect on fertility functions (increase in the number of offspring). Based on the obtained data it can be assumed that the continuous intake of bentonite by the animal organism is one of the factors of their microbiome improvement, which affects on a plenty of physiological functions, including animals reproduction. It is possible that smectite sorbents also enrich the body of mice by certain essential mineral elements (silicon, etc.) and has cytomucoprotective properties concerning the mucous membranes of the macroorganism

Unraveling the sequence of serpentinization reactions : petrography, mineral chemistry, and petrophysics of serpentinites from MAR 15°N (ODP Leg 209, Site 1274)

Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 33 (2006): L13306, doi:10.1029/2006GL025681.The results of detailed textural, mineral chemical, and petrophysical studies shed new light on the poorly constrained fluid-rock reaction pathways during retrograde serpentinization at mid-ocean ridges. Uniformly depleted harzburgites and dunites from the Mid-Atlantic Ridge at 15°N show variable extents of static serpentinization. They reveal a simple sequence of reactions: serpentinization of olivine and development of a typical mesh texture with serpentine-brucite mesh rims, followed by replacement of olivine mesh centers by serpentine and brucite. The serpentine mesh rims on relic olivine are devoid of magnetite. Conversely, domains in the rock that are completely serpentinized show abundant magnetite. We propose that low-fluid-flux serpentinization of olivine to serpentine and ferroan brucite is followed by later stages of serpentinization under more open-system conditions and formation of magnetite by the breakdown of ferroan brucite. Modeling of this sequence of reactions can account for covariations in magnetic susceptibility and grain density of the rocks.Funding for this research was provided by USSSP and NSF-OCE grant 9986135. WB acknowledges support through a fellowship by the Deep Ocean Exploration Institute