Experimental study of the topological flow transformations in an aerial vortex bioreactor with a floating washer.

Background: Research into the flow structure in an aerial vortex bioreactor is relevant for developing the methods for growing cell cultures. Determining the optimal cultivation condition for a certain process is especially important in the case when such parameters of the medium as density and viscosity significantly change with the culture growth in the bioreactor.

Methods And Results: The research of the flow dynamic was carried out in an 8.

Magnetotransport in Graphene/PbSnTe Heterostructures: Finding a Way to Avoid Catastrophe.

While heterostructures are ubiquitous tools enabling new physics and device functionalities, the palette of available materials has never been richer. Combinations of two emerging material classes, two-dimensional materials and topological materials, are particularly promising because of the wide range of possible permutations that are easily accessible. Individually, both graphene and PbSnTe (PST) are widely investigated for spintronic applications because graphene's high carrier mobility and PST's topologically protected surface states are attractive platforms for spin transport.

Ocular counter-roll is less affected in experienced versus novice space crew after long-duration spaceflight.

Otoliths are the primary gravity sensors of the vestibular system and are responsible for the ocular counter-roll (OCR). This compensatory eye torsion ensures gaze stabilization and is sensitive to a head roll with respect to gravity and the Gravito-Inertial Acceleration vector during, e.g.

The Role of Different Afferent Systems in the Modulation of the Otolith-Ocular Reflex After Long-Term Space Flights.

Background: The vestibular (otolith) function is highly suppressed during space flight (SF) and the study of these changes is very important for the safety of the space crew during SF missions. The vestibular function (particularly, otolith-ocular reflex-OOcR) in clinical and space medicine is studied using different methodologies. However, different methods and methodologies can influence the outcome results.

Dual vortex breakdown in a two-fluid whirlpool.

Looking for an optimal flow shape for culture growth in vortex bioreactors, an intriguing and impressive structure has been observed that mimics the strong swirling flows in the atmosphere (tornado) and ocean (waterspout). To better understand the flow nature and topology, this experimental study explores the development of vortex breakdown (VB) in a lab-scale swirling flow of two immiscible fluids filling a vertical cylindrical container. The rotating bottom disk drives the circulation of both fluids while the sidewall is stationary.

Alterations of Functional Brain Connectivity After Long-Duration Spaceflight as Revealed by fMRI.

The present study reports alterations of task-based functional brain connectivity in a group of 11 cosmonauts after a long-duration spaceflight, compared to a healthy control group not involved in the space program. To elicit the postural and locomotor sensorimotor mechanisms that are usually most significantly impaired when space travelers return to Earth, a plantar stimulation paradigm was used in a block design fMRI study. The motor control system activated by the plantar stimulation involved the pre-central and post-central gyri, SMA, SII/operculum, and, to a lesser degree, the insular cortex and cerebellum.

Potential high- superconducting lanthanum and yttrium hydrides at high pressure.

A systematic structure search in the La-H and Y-H systems under pressure reveals some hydrogen-rich structures with intriguing electronic properties. For example, LaH is found to adopt a sodalite-like face-centered cubic (fcc) structure, stable above 200 GPa, and LaH a 2/ space group structure. Phonon calculations indicate both are dynamically stable; electron phonon calculations coupled to Bardeen-Cooper-Schrieffer (BCS) arguments indicate they might be high- superconductors.

Quasimolecules in Compressed Lithium.

Under high pressure, some materials form electrides, with valence electrons separated from all atoms and occupying interstitial regions. This is often accompanied by semiconducting or insulating behavior. The interstitial quasiatoms (ISQ) that characterize some high pressure electrides have been postulated to show some of the chemical features of atoms, including the potential of forming covalent bonds.

Topological Surface States in Dense Solid Hydrogen.

Metallization of dense hydrogen and associated possible high-temperature superconductivity represents one of the key problems of physics. Recent theoretical studies indicate that before becoming a good metal, compressed solid hydrogen passes through a semimetallic stage. We show that such semimetallic phases predicted to be the most stable at multimegabar (∼300  GPa) pressures are not conventional semimetals: they exhibit topological metallic surface states inside the bulk "direct" gap in the two-dimensional surface Brillouin zone; that is, metallic surfaces may appear even when the bulk of the material remains insulating.

Dense Hydrocarbon Structures at Megabar Pressures.

The structure, bonding, and other properties of phases in the carbon-hydrogen system over a range of conditions are of considerable importance to a broad range of scientific problems. However, the phase diagram of the C-H system at high pressures and temperatures is still not known. To search for new low-energy hydrocarbon structures, we carried out systematic structure prediction calculations for the C-H system from 100 to 300 GPa.

[The Effects of Optokinetic Stimulation on Visual-Manual Tracking under Support-Proprioceptive Deprivation.].

To determine the effects of additional visual stimuli (retinal optokinetic stimulation - ROKS) on characteristics of the visual-manual tracking (VMT) without support and with decreased proprioceptive afferentation there was used a horizontal "dry" immersion. Altogether 18 subjects aged from 19 to 31 years participated in the study and they were submerged into the immersion bath from 5 to 7 days. There was evaluated performance of the VMT in tasks to pursue the jerky (saccadically) and smooth (linear, pendular and circular) movement of a point visual stimulus before, during and after immersion.

[EFFECT OF REPEATED SPACE FLIGHTS ON OCULAR TRACKING].

The paper reports the results of studying the vestibular and ocular intersensory interactions and eye tracking function in 32 cosmonauts on maiden and repeated missions to the International space station. Mission duration ranged from 125 to 215 days. The cosmonauts were tested twice pre launch (baseline data collection) and on days R + 1/2, 4/5 and 8/9.

Decreased otolith-mediated vestibular response in 25 astronauts induced by long-duration spaceflight.

The information coming from the vestibular otolith organs is important for the brain when reflexively making appropriate visual and spinal corrections to maintain balance. Symptoms related to failed balance control and navigation are commonly observed in astronauts returning from space. To investigate the effect of microgravity exposure on the otoliths, we studied the otolith-mediated responses elicited by centrifugation in a group of 25 astronauts before and after 6 mo of spaceflight.

Chemical bonding in hydrogen and lithium under pressure.

Though hydrogen and lithium have been assigned a common column of the periodic table, their crystalline states under common conditions are drastically different: the former at temperatures where it is crystalline is a molecular insulator, whereas the latter is a metal that takes on simple structures. On compression, however, the two come to share some structural and other similarities associated with the insulator-to-metal and metal-to-insulator transitions, respectively. To gain a deeper understanding of differences and parallels in the behaviors of compressed hydrogen and lithium, we performed an ab initio comparative study of these systems in selected identical structures.

[Computerized method of objectification of dizziness and vertigo and differential diagnostic of vestibulopathies].

Objective: To create a complex computerized method of objectification of dizziness and vertigo, and differentiation of vestibulopathies of various geneses using electrooculography approach that allows to record and analyze spontaneous, vestibular- and visually-induced eye movements, with the following classification (discriminant) analysis of the results obtained.

Material And Methods: The study involved 69 patients of different sex and age complained of dizziness, vertigo and disequilibrium, and 64 healthy men. Based on the results of clinical examination, patients were divided into three groups: patients with peripheral vestibulopathy, patients with central vestibulopathy and patients with psychogenic vestibulopathy.

Predictive Levels of CD24 in Peripheral Blood Leukocytes for the Early Detection of Colorectal Adenomas and Adenocarcinomas.

CD24 is expressed in 90% of colorectal adenomas and adenocarcinomas. Colorectal cancer (CRC) can be mostly prevented but average risk population screening by stool testing or colonoscopy faces many hurdles. Blood testing is clinically needed.

Origin of Transitions between Metallic and Insulating States in Simple Metals.

Unifying principles that underlie recently discovered transitions between metallic and insulating states in elemental solids under pressure are developed. Using group theory arguments and first-principles calculations, we show that the electronic properties of the phases involved in these transitions are controlled by symmetry principles. The valence bands in these systems are described by simple and composite band representations constructed from localized Wannier functions centered on points unoccupied by atoms, and which are not necessarily all symmetrical.

[VESTIBULAR FUNCTION AFTER REPEATED SPACE FLIGHTS].

Results of the vestibular function testing of 32 cosmonauts on return from repeated 125- to 215-day space flights (SF) on the International space station are presented. The cosmonauts were tested twice before flight (baseline data collection) and on days 1-2, 4-5 and 8-9 after landing. Electro- and video-oculography were used to register simultaneously eye and head movements.

Aromaticity, closed-shell effects, and metallization of hydrogen.

CONSPECTUS: Recent theoretical and experimental studies reveal that compressed molecular hydrogen at 200-350 GPa transforms to layered structures consisting of distorted graphene sheets. The discovery of chemical bonding motifs in these phases that are far from close-packed contrasts with the long-held view that hydrogen should form simple, symmetric, ambient alkali-metal-like structures at these pressures. Chemical bonding considerations indicate that the realization of such unexpected structures can be explained by consideration of simple low-dimensional model systems based on H6 rings and graphene-like monolayers.

Lack of CD24 expression in mice reduces the number of leukocytes in the colon.

CD24 is an extensively glycosylated membrane protein that is linked to the membrane via a glycosyl-phosphatidylinositol (GPI)-anchor. In mice, CD24 is expressed by hematopoietic and non-hematopoietic cells. CD24-/- mice do not have gross immunological defects, but detailed analysis revealed strongly reduced responses in an experimental autoimmune encephalomyelitis (EAE) model and a massive proliferation of T cells under lymphopenic conditions.

Aspirin but not meloxicam attenuates early atherosclerosis in apolipoprotein E knockout mice.

Background: Atherosclerosis is a complex vascular inflammatory disease. In the last decade it was suggested that nonsteroidal anti-inflammatory drugs (NSAIDs) and in particular inhibition of cyclooxygenase (COX)-2 are associated with an increase in cardiovascular morbidity and mortality. Aspirin is known to reduce the incidence and mortality from ischemic heart disease and is a mainstay in the prevention of vascular complications of atherosclerosis.

Role of CD24 polymorphisms in the susceptibility to inflammatory bowel disease.

Background: Inflammatory bowel disease (IBD) results from an inappropriate inflammatory response in which genetic, immune, and environmental factors all play important roles. Recently, single nucleotide polymorphisms (SNPs) in the CD24 gene have been associated with the development of several autoimmune diseases.

Aim: To evaluate whether CD24 SNPs, are associated with risk of ulcerative colitis (UC) and Crohn's disease (CD).

CD24 knockout prevents colorectal cancer in chemically induced colon carcinogenesis and in APC(Min)/CD24 double knockout transgenic mice.

Increased expression of CD24 is seen in a large variety of solid tumors, including up to 90% of gastrointestinal (GI) tumors. Stable derivatives of SW480 colorectal cancer (CRC) cells that overexpress CD24 proliferate faster, and increase cell motility, saturation density, plating efficiency, and growth in soft agar. They also produce larger tumors in nude mice as compared to the parental SW480 cells.

Arthroscopic treatment of tibial spine fracture in children with a cannulated Herbert screw.

Background: Avulsion fractures of the anterior tibial intercondylar eminence in childhood are rare and are severe injuries of the knee. Since the injury is equivalent in aetiology with ruptures of the anterior cruciate ligament, the treatment requires anatomic reduction and preservation of the stability of the joint. The aim of the study was to demonstrate our experiences with the arthroscopy-guided Herbert-screw fixation in the treatment of displaced tibial eminence fractures in children.

[The effects of support-proprioceptive deprivation on visual-manual tracking and vestibular function].

To determine the effects of support and proprioceptive afferentation on characteristics of the visual-manual tracking (VMT) we used a model of weightlessness - horizontal "dry" immersion. Altogether 30 subjects who stayed in immersion bath from 5 to 7 days were examined to evaluate the accuracy of VMT in tasks to pursue the jerky (saccadically) and smooth (linear, pendular and circular) movement of a point visual stimulus. Examinations were performed before, during and after immersion using electrooculography (to record eye movements) and a joystick (to record hand movements) with a biological visual feedback - one of the two visible stimuli on the screen matched the current angle of the joystick handle.