directional movement
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Author(s):  
Н.Н. Ефремов

В статье рассматривается модель пространственных предложений якутского языка, которыми описываются отношения адлокации и директив - финиша. Подобные предложения формируются конструкциями, предикат которых выражается глаголами направленного движения, ориентированного относительно конечного пункта, а актант - локализатор обозначается синтетическими и аналитическими формами. Их типовая модель представлена тремя структурными вариантами: падежным, с послелогом диэки, с наречиями и именами. Варианты в соответствии с лексико - грамматическим характером глаголов движения, выступающих предикатами, а также имен и наречий, функционирующих в роли локализаторов, наделяются теми или иными семантическими модификациями. Падежный вариант представляется относительно большим числом модификаций в связи с их сочетаемостным потенциалом, что позволяет расценивать их как ядерные средства выражения анализируемых отношений. The article discusses the model of spatial sentences of the Yakut language, which describe the relation between adlocation and direction - finish. Such sentences are formed by constructions, the predicate of which is expressed by verbs of directional movement, oriented relative to the final point, and the localizing actant is designated by certain synthetic and analytical forms. Their typical model is represented by three structural variants: case, with postposition dieki, with adverbs and names. Variants in accordance with the lexical and grammatical nature of verbs of motion, acting as predicates, as well as names and adverbs, functioning as localizers, are endowed with one or another semantic modification. The case variant is represented by a relatively large number of modifications due to their collocational potential, which allows us to regard them as core means of expressing the analyzed relations.


2021 ◽  
Author(s):  
Nadine Urban ◽  
Maximillian Hoerner ◽  
Wilfried Weber ◽  
Can Dincer

Circumventing the limitations of current bioassays, we introduce the first light-controlled assay, the OptoAssay, towards wash- and pump-free point-of-care diagnostics. Extending the capabilities of standard bioassays with light-dependent and reversible interaction of optogenetic switches, OptoAssays enable a bi-directional movement of assay components, only by changing the wavelength of light. Combined with smartphones, OptoAssays obviate the need for external flow control systems like pumps or valves and signal readout devices.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2365-2365
Author(s):  
Shireen J. Usman ◽  
Thomas Conley ◽  
Hannah E. Whitehead ◽  
Wojciech Wojciechowski ◽  
Kaye Thomas ◽  
...  

Abstract INTRODUCTION Naked nuclei (NN) are observed upon examining bone marrow aspirate slides from healthy individuals and from those with hematologic malignancies, but are not well understood. Without characteristic findings like cytoplasm or plasma membrane, NN are considered remnants of slide preparation or are discounted as cells of undetermined significance. NN have been associated with poor prognosis in several solid cancers. Understanding the significance of NN in hematologic malignancies such as acute myelogenous leukemia (AML) may elucidate valuable diagnostic and prognostic knowledge. Decellularized Wharton's jelly matrix (DWJM) is an extra cellular matrix (ECM)-based in vitro model that shares similar elements with the bone marrow ECM and can be used as scaffolding to culture leukemia cells. We hypothesize that NN exist in AML and interact with other cells, suggesting potential biological relevance within the bone marrow microenvironment. METHODS Primary AML samples obtained by leukapheresis were cultured in suspension with growth media or in the presence of DWJM submerged in growth media. In samples grown with DWJM, cells that were non-adherent to the matrix were collected first and then adherent cells were isolated by treating DWJM with collagenase. Live cells were stained with CellVue Maroon (CVM) for membrane, CellTracker Green (CTG) for cytoplasm, and Hoechst 33342 for nucleus, followed by analysis with Amnis/Luminex ImageStream-X imaging flow cytometer (Figure 1A). NN were defined as events positive for nuclear stain and negative for cytoplasmic and membrane stains (Figure 1B). 3-D movement of adherent AML cells in DWJM was captured in real time using confocal microscopy. Fixed cells from leukemia cell line K562 served as a control for movement. NN (Hoechst positive only), non-nucleated (Hoechst negative/CTG positive), and nucleated cells (Hoechst and CTG positive) were identified by fluorescent labeling. NN were also observed after isolation by cell sorting. Cell speed, cell displacement from origin, and change in distance to closest neighboring cell over time were measured. Additionally, flow sorted NN were examined by immunohistochemistry (IHC). RESULTS Adherent populations contained significantly more NN than non-adherent and suspension populations. The frequency of NN in matrix adherent cells ranged from 0.4-2.4% at day 3 and 0.5-5.4% at day 7 of culture (Figure 1C). Through confocal microscopic analysis, we observed NN, nucleated, and non-nucleated cells moving at speeds ranging from 0.002-0.08 µm/sec. Fixed cells showed no discernible movement in DWJM. The average speed of NN [0.019 mm/s, SD 0.011] significantly differed from the average speed of nucleated and non-nucleated cells [0.027 mm/s, SD 0.016] (p=0.004) (Figure 1E). To demonstrate directional movement, we measured change in distance between NN and closest neighboring nucleated or non-nucleated cells over time. Cells (nucleated and non-nucleated) and NN moved closer to each other over time suggesting directional movement (p=0.001) (Figure 1D). NN also showed movement in DWJM after isolation by cell sorting. IHC analysis showed sorted NN stained positive for nuclear lamin A/C, which are considered markers of nuclear membrane (Figure 1F). CONCLUSIONS Our findings confirm that NN are present in primary AML cells cultured in vitro using ourECM-based model and that they can be isolated using flow cytometry. Additionally, NN display directional movement in DWJM suggesting that they interact with other cells and may be biologically relevant structures in the bone marrow microenvironment. Figure 1 Figure 1. Disclosures Baran: AstraZeneca/Acerta: Research Funding. Chu: Pfizer: Current equity holder in publicly-traded company; Acerta/AstraZeneca: Research Funding; TG Therapeutics: Research Funding.


2021 ◽  
Author(s):  
Shuai Yang

Abstract In the past scientific cognition, changes in the magnetic field produce electric field, so when there is current and voltage generation, need to have a change in magnetic flux, However, in the process of studying the nature of magnetization, we found that the microscopic formation of a magnetic field is the directional movement of positive and negative charges, under the guidance of this theory, we use other methods, realize the separation of positive and negative charges, observation of induced current generation, this can be used as another way to generate electricity.


2021 ◽  
Author(s):  
Daisuke Nakane ◽  
Gen Enomoto ◽  
Annegret Wilde ◽  
Takayuki Nishizaka

Many cyanobacteria, which use light as an energy source via photosynthesis, show directional movement towards or away from a light source. However, the molecular and cell biological mechanisms for switching the direction of movement remain unclear. Here, we visualized type IV pilus-dependent cell movement in the rod-shaped thermophilic cyanobacterium Thermosynechococcus vulcanus using optical microscopy at physiological temperature and light conditions. Positive and negative phototaxis were controlled on a short time scale of 1 min. The cells smoothly moved over solid surfaces towards green light, but the direction was switched to backward movement when we applied additional blue light illumination. The switching was mediated by three photoreceptors, SesA, SesB and SesC, which have cyanobacteriochrome photosensory domains and synthesis/degradation activity of the bacterial second messenger cyclic dimeric GMP (c-di-GMP). Our results suggest that the decision-making process for directional switching in phototaxis involves light-dependent changes in the cellular concentration of c-di-GMP. Furthermore, we reveal that rod-shaped cells can move perpendicular to the light vector, indicating that the polarity can be controlled not only by pole-to-pole regulation but also within-a-pole regulation. This study provides insights into previously undescribed rapid bacterial polarity regulation via second messenger signalling with high spatial resolution.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Patricia P. M. Mathiassen ◽  
Anant K. Menon ◽  
Thomas Günther Pomorski

AbstractTransbilayer movement of phospholipids in biological membranes is mediated by a diverse set of lipid transporters. Among them are scramblases that facilitate a rapid bi-directional movement of lipids without metabolic energy input. Here, we established a new fluorescence microscopy-based assay for detecting phospholipid scramblase activity of membrane proteins upon their reconstitution into giant unilamellar vesicles formed from proteoliposomes by electroformation. The assay is based on chemical bleaching of fluorescence of a photostable ATTO-dye labeled phospholipid with the membrane-impermeant reductant sodium dithionite. We demonstrate that this new methodology is suitable for the study of the scramblase activity of the yeast endoplasmic reticulum at single vesicle level.


2021 ◽  
Vol 7 (29) ◽  
pp. eabf3882
Author(s):  
Joshua François ◽  
Adithan Kandasamy ◽  
Yi-Ting Yeh ◽  
Amy Schwartz ◽  
Cindy Ayala ◽  
...  

Neutrophils migrating through extravascular spaces must negotiate narrow matrix pores without losing directional movement. We investigated how chemotaxing neutrophils probe matrices and adjust their migration to collagen concentration ([col]) changes by tracking 20,000 cell trajectories and quantifying cell-generated 3D matrix deformations. In low-[col] matrices, neutrophils exerted large deformations and followed straight trajectories. As [col] increased, matrix deformations decreased, and neutrophils turned often to circumvent rather than remodel matrix pores. Inhibiting protrusive or contractile forces shifted this transition to lower [col], implying that mechanics play a crucial role in defining migratory strategies. To balance frequent turning and directional bias, neutrophils used matrix obstacles as pivoting points to steer toward the chemoattractant. The Actin Related Protein 2/3 complex coordinated successive turns, thus controlling deviations from chemotactic paths. These results offer an improved understanding of the mechanisms and molecular regulators used by neutrophils during chemotaxis in restrictive 3D environments.


2021 ◽  
Vol 118 (27) ◽  
pp. e2101807118
Author(s):  
Haichao Wu ◽  
Benjamin Greydanus ◽  
Daniel K. Schwartz

Micro/nanoswimmers convert diverse energy sources into directional movement, demonstrating significant promise for biomedical and environmental applications, many of which involve complex, tortuous, or crowded environments. Here, we investigated the transport behavior of self-propelled catalytic Janus particles in a complex interconnected porous void space, where the rate-determining step involves the escape from a cavity and translocation through holes to adjacent cavities. Surprisingly, self-propelled nanoswimmers escaped from cavities more than 20× faster than passive (Brownian) particles, despite the fact that the mobility of nanoswimmers was less than 2× greater than that of passive particles in unconfined bulk liquid. Combining experimental measurements, Monte Carlo simulations, and theoretical calculations, we found that the escape of nanoswimmers was enhanced by nuanced secondary effects of self-propulsion which were amplified in confined environments. In particular, active escape was facilitated by anomalously rapid confined short-time mobility, highly efficient surface-mediated searching for holes, and the effective abolition of entropic and/or electrostatic barriers at the exit hole regions by propulsion forces. The latter mechanism converted the escape process from barrier-limited to search-limited. These findings provide general and important insights into micro/nanoswimmer mobility in complex environments.


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