Directional Movement Research Articles

Class II kinesin-12 facilitates cell plate formation by transporting cell plate materials in the phragmoplast.

Cell plate formation in plants is a complex process orchestrated by the targeted delivery of Golgi-derived and endosomal vesicles containing cell plate components to the phragmoplast midzone. It has long been hypothesized that vesicles are directionally transported along phragmoplast microtubules by motor proteins. However, the mechanisms governing the accumulation and immobilization of vesicles at the phragmoplast midzone remain elusive, and the motor protein responsible has yet to be identified. Here we show that the plant-specific class II kinesin-12 (kinesin12-II) functions as a motor protein that drives vesicle transport towards the phragmoplast midzone in the moss Physcomitrium patens. In the kinesin12-II mutant, the directional movement of cell plate materials towards the midzone and their retention were abolished, resulting in delayed cell plate formation and phragmoplast disassembly. A macroscopic phenotype arising from kinesin12-II disruption was the impediment to gametophore development. We showed that this defect was attributable to the production of aneuploid and polyploid cells in the early gametophore, where chromosome missegregation and cytokinesis failure occurred. These findings suggest that plant kinesin-12 has evolved to acquire a unique and critical function that facilitates cell plate formation in the presence of phragmoplasts.

A Lithium Complex Ferroelectric with High Curie Temperature: [Li(1,10-Phenanthroline)2]I.

Paraelectric-ferroelectric phase transitions have been mainly acknowledged by the order-disorder type in most molecular ferroelectrics or the displacive type in inorganic ferroelectrics. However, reports regarding symmetry-breaking ferroelectric phase transitions induced by distortion in the coordination geometry have been scarce. In this study, we present a lithium complex molecular ferroelectric [Li(1,10-phenanthroline)2]I, which undergoes an Aizu mmmFmm2 type symmetry-breaking ferroelectric phase transition at 371 K. Its ferroelectricity has been identified by the geometric distortion of the lithium ions coordination environment and the concomitant directional movement of iodide ions. Besides, the ferroelectric loop of [Li(1,10-phenanthroline)2]I can be readily obtained from a polarized polycrystalline pellet at room temperature; in addition, its nonlinear optical signal is comparable to that of KH2PO4 (KDP). To the best of our knowledge, [Li(1,10-phenanthroline)2]I represents the first lithium-based organic complex ferroelectric exhibiting a coordination geometry-triggered symmetry-breaking ferroelectric phase transition. This work will provide significant inspiration for the design of novel molecular ferroelectrics.

Enhancing FOREX Market Predictions: A Comparative Study of Candlestick Patterns and the MIDDAM Patterns

Candlestick patterns are widely recognized as tools for predicting price movements, gaining popularity in the stock market. However, their applicability in the FOREX market, which operates continuously 24 hours daily, remains uncertain. This study assesses the accuracy of widely known candlestick patterns, particularly Doji patterns, in the FOREX market. We analyze the top eight most-traded currency pairsEUR/USD, EUR/GBP, GBP/USD, GBP/JPY, USD/JPY, USD/CHF, AUD/USD, and XAU/USDusing 13 years of data. The findings reveal that Doji patterns are unreliable indicators of reversals in the FOREX market. Instead, this research introduces a new candlestick pattern, MInimal Dierence in shadow for Directional Analytical Movement (MIDDAM), which is designed for both uptrends and downtrends and significantly improves predictive accuracy. Extensive experiments demonstrate that the proposed patterns outperform traditional ones in protability and trade success. By comparing the effectiveness of these patterns in real market simulations involving over 38 million 1-minute historical candles, MIDDAM patterns yield 138 times more protable than Doji patterns, achieving a win-to-loss ratio of 6:2 across the tested currency pairs. This study underscores the potential of MIDDAM patterns for more reliable predictions and superior trading performance in the FOREX market.

Cerebellar control of targeted tongue movements

AbstractThe cerebellum is critical for coordinating movements related to eating, drinking and swallowing, all of which require proper control of the tongue. Cerebellar Purkinje cells can encode tongue movements, but it is unclear how their simple spikes and complex spikes induce changes in the shape of the tongue that contribute to goal‐directed movements. To study these relations, we recorded and stimulated Purkinje cells in the vermis and hemispheres of mice during spontaneous licking from a stationary or moving water spout. We found that Purkinje cells can encode rhythmic licking with both their simple spikes and complex spikes. Increased simple spike firing during tongue protrusion induces ipsiversive bending of the tongue. Unexpected changes in the target location trigger complex spikes that alter simple spike firing during subsequent licks, adjusting the tongue trajectory. Furthermore, we observed increased complex spike firing during behavioural state changes at both the start and the end of licking bouts. Using machine learning, we confirmed that alterations in Purkinje cell activity accompany licking, with different Purkinje cells often exerting heterogeneous encoding schemes. Our data highlight that directional movement control is paramount in cerebellar function and that modulation of the complex spikes and that of the simple spikes are complementary during acquisition and execution of sensorimotor coordination. These results bring us closer to understanding the clinical implications of cerebellar disorders during eating, drinking and swallowing. imageKey points When drinking, mice make rhythmic tongue movements directed towards the water source. Cerebellar Purkinje cells can fire rhythmically in tune with the tongue movements. Purkinje cells encode changes in the position of the water source with complex spikes. Purkinje cell simple spike firing affects the direction of tongue movements. Purkinje cells that report changes in the position of the target can also adjust movements in the right direction.

High-resolution fleezers reveal duplex opening and stepwise assembly by an oligomer of the DEAD-box helicase Ded1p

DEAD-box RNA-dependent ATPases are ubiquitous in all domains of life where they bind and remodel RNA and RNA-protein complexes. DEAD-box ATPases with helicase activity unwind RNA duplexes by local opening of helical regions without directional movement through the duplexes and some of these enzymes, including Ded1p from Saccharomyces cerevisiae, oligomerize to effectively unwind RNA duplexes. Whether and how DEAD-box helicases coordinate oligomerization and unwinding is not known and it is unclear how many base pairs are actively opened. Using high-resolution optical tweezers and fluorescence, we reveal a highly dynamic and stochastic process of multiple Ded1p protomers assembling on and unwinding an RNA duplex. One Ded1p protomer binds to a duplex-adjacent ssRNA tail and promotes binding and subsequent unwinding of the duplex by additional Ded1p protomers in 4–6 bp steps. The data also reveal rapid duplex unwinding and rezipping linked with binding and dissociation of individual protomers and coordinated with the ATP hydrolysis cycle.

Inversion of circularly polarized luminescence by electric current flow during transition.

The development of chiral compounds exhibiting circularly polarized luminescence (CPL) has advanced remarkably in recent years. Designing CPL-active compounds requires an understanding of the electric transition dipole moment (μ) and the magnetic transition dipole moment (m) in the excited state. However, while the direction and magnitude of μ can, to some extent, be visually inferred from chemical structures, m remains elusive, posing challenges for direct predictions based on structural information. This study utilized binaphthol, a prominent chiral scaffold, and achieved CPL-sign inversion by strategically varying the substitution positions of phenylethynyl (PE) groups on the binaphthyl backbone, while maintaining consistent axial chirality. Theoretical investigation revealed that the substitution position of PE groups significantly affects the orientation of m in the excited state, leading to CPL-sign inversion. Furthermore, we propose that this CPL-sign inversion results from a reversal in the rotation of instantaneous current flow during the S1 → S0 transition, which in turn alters the orientation of m. The current flow can be predicted from the chemical structure, allowing anticipation of the properties of m and, consequently, the characteristics of CPL. This insight provides a new perspective in designing CPL-active compounds, particularly for C2-symmetric molecules where the S1 → S0 transition predominantly involves LUMO → HOMO transitions. If μ represents the directionality of electron movement during transitions, i.e., the "difference" in electron locations before and after transitions, then m could be represented as the "path" of electron movement based on the current flow during the transition.

On-chip non-contact mechanical cell stimulation - quantification of SKOV-3 alignment to suspended microstructures.

Although the accumulation of random genetic mutations has been traditionally viewed as the main cause of cancer progression, altered mechanobiological profiles of the cells and microenvironment also play a major role as a mutation-independent element. To probe the latter, we have previously reported a microfluidic cell-culture platform with an integrated flexible actuator and its application for sequential cyclic compression of cancer cells. The platform is composed of a control microchannel in a top layer for introducing external pressure, and a polydimethylsiloxane (PDMS) membrane from which a monolithically-integrated actuator protrudes downwards into a cell-culture microchannel. When actuated, the integrated actuator, referred to as micro-piston, transfers the pressure from the control channel as a mechanical force to the cells underneath. When not actuated, the micro-piston remains suspended above cells, separated from the latter via a liquid-filled gap of ∼108 μm. Despite the lack of direct physical contact between the micro-piston and cells in the latter arrangement, we observed distinct alignment of SKOV-3 ovarian cancer cells to the piston shape. To characterize this observation, micro-piston localization, shape, and size were adjusted and the directionality of a mono-layer of SKOV-3 cells relative to the suspended structure was probed. Cell alignment analysis was performed in a novel, label-free approach by measuring elongation angles of whole cell bodies with respect to micro-piston peripheries. Alignment of SKOV-3 cells to the structure outline was significant for circular, triangular and square micro-piston when compared to control areas without micro-piston on the same chip. The effect was present irrespective of whether cells were loaded with micro-pistons in static position (∼108 μm gap) or actively retracted using vacuum (>108 μm gap). Similar alignment was not observed for MCF7 cancer cells and MCF10A non-cancerous epithelial cells. The reported observation of directional movement and growth of SKOV-3 cells towards the region under micro-pistons point towards a to-date unexplored mechanotactic behavior of these cells, warranting future investigations regarding the mechanisms involved and the role these may play in cancer.

(South-)West to (North-)East Directional Movement of Respiratory Virus Activity in Europe: A Spatial-Temporal Cross-Sectional Study.

(South-)West to (North-)East Directional Movement of Respiratory Virus Activity in Europe: A Spatial-Temporal Cross-Sectional Study.

Spatial Movement With Explicit Memory and Nonlocal Pregnancy Delay

ABSTRACTIn depicting animal movement, besides considering spatial memory, the pregnancy period of the animals themselves should also be taken into account. This article proposes a novel single‐population model with discrete memory delay and nonlocal spatiotemporal gestation delay. Assuming the positive equilibrium is locally stable without spatiotemporal delay, the study investigates two types of directional movements using memory delay and gestation delay as control parameters. The research shows that for the positive memory‐based diffusion coefficient, the system destabilizes through homogeneous/nonhomogeneous Hopf bifurcations, but for the negative memory diffusion coefficient, the system not only undergo Hopf bifurcations but also becomes unstable through Turing bifurcations, and may even exhibit Turing–Hopf bifurcation. Finally, we use a diffusive logistic model with predation behavior as an example to numerically simulate the theoretical results and also discover stability switch phenomena.

금리 변동을 반영한 LSTM 기반 주가 예측 모델 연구

Due to the recent impact of inflation, central banks have maintained a policy of raising interest rates, highlighting the growing importance of financial market forecasting that reflects these economic conditions. However, there has been a lack of recent studies in Korea that consider interest rate in stock price prediction. In this study, we aimed to improve prediction accuracy by incorporating interest rates as a variable into stock price prediction models. For this purpose, we utilized the LSTM algorithm and trained the model on historical data from periods of high stock market volatility to predict the KOSPI index. Additionally, we conducted a multi-faceted analysis of the impact of interest rates through market conditions and sector-specific analyses. By employing various evaluation metrics, we performed both stock price prediction and directional movement prediction simultaneously. As a result, the model that incorporated interest rates demonstrated a 48.31% reduction in RMSE, compared to the baseline model, with the performance difference being statistically significant. This study confirms that interest rates are a critical variable in stock price prediction and that models reflecting interest rate fluctuations can enhance predictive performance.

High-Performing Direct X-Ray Detection Made of One-Dimensional Perovskite-Like (TMHD)SbBr5 Single Crystal With Anisotropic Response.

3D and 2D organic hybrid perovskites, as well as double perovskites, have demonstrated their suitability for direct X-ray detection. However, the sensitivity and stability of 3D perovskite X-ray detectors are currently being hindered by the existing constraints on ion movement. Therefore, there is an immediate need to develop X-ray detectors that are both highly sensitive and stable while also being environmentally friendly. The novel low-dimensional perovskites demonstrate exceptional inherent stability and effectively mitigate ion migration, thereby showcasing their remarkable photoelectric performance. Inspired by this, a solution crystallization method is employed to synthesize novel single crystals (SCs) of one dimensional (1D) (TMHD)SbBr5. The dimensions of the chained (TMHD)SbBr5 SC are 13×1.3×1.2 mm3 in size. The device based on a perovskite chain (TMHD)SbBr5 exhibits unique anisotropic X-ray detection performance with a sensitivity of 62.8 and 30.5 µC Gyair -1cm-2 in the parallel and perpendicular orientations, respectively. It can lead to the directional movement of ions, resulting in large carrier mobility under the action of electric fields, and effectively increase the sensitivity to X-ray detection.

Role of thermal and electric fields in the failure mechanism of metallized film capacitors: insights from molecular chain dynamics within polymer dielectrics

Abstract The seamless integration of modern power systems and renewable energy sources heavily relies on advanced power electronics technologies, with metallized film capacitors (MFCs) playing a pivotal role in this ecosystem. Ensuring the operational efficiency and safety of these systems necessitates a thorough understanding of MFC failure mechanisms. In this study, molecular dynamics and density functional theory are employed to analyze the microscopic parameters governing MFC failure characteristics across a temperature spectrum of 25 °C–105 °C. The investigation is geared toward theoretically assessing MFC failure mechanisms under varying voltage ramp rates. Our findings highlight temperature as the primary influencer of failure characteristics at slower ramp rates (50 and 75 V s−1), where the interplay between carrier transport and intermolecular interaction energy dictates the trend of capacitor failure voltage—a pattern of initial increase followed by decrease with temperature. Conversely, higher voltage ramp rates accentuate the significance of the electric field. At a rapid ramp rate of 900 V s−1, the dominance of the electric field mitigates the impact of temperature, resulting in minimal variation in failure voltage across temperatures. Moreover, under intense electric fields, the reduction in free volume within the polypropylene unit exhibits a rapid decline, significantly constraining the mobility of molecular chains. Consequently, certain segments of these molecular chains exhibit localized alignment and directional movement. The rise in molecular polarity and reduction in energy gap contribute to substantially lower failure voltages compared to slower ramp rates. This study offers robust theoretical insights into comprehending MFC failure characteristics, thereby ensuring their reliable operation in demanding environments.

Effects of magnetotactic bacteria (MTB) on membrane fouling control in an ultrafiltration treatment of chromium-containing surface water.

Ultrafiltration membranes are widely used in the treatment of surface water. However, membrane fouling is a core issue that needs to be addressed in its application. Magnetotactic bacteria (MTB) show early film-forming and magnetotactic behaviour in the presence of external magnetic fields. The objective of this study was to alleviate membrane fouling in ultrafiltration membranes using MTB, which can prioritise film formation and show directional movement under external magnetic fields. The concentration of Cr6+ in the water was 10 mg/L, and the dosage of MTB was 10 mg/L. Results show that the transmembrane pressure of the ultrafiltration membrane decreased by 5 kPa following the application of a magnetic field of 33.71 mT for a period of 90 min, and the membrane fouling could therefore be effectively controlled. With the addition of MTB, the average removal of Cr6+ from water by the ultrafiltration system was 20.10%, which was 14.56% higher than that of the conventional ultrafiltration system. The average removal of chromaticity was 20.13%, which was 10% higher than that achieved by the conventional ultrafiltration system. Furthermore, MTB progressively developed into the predominant flora during the operational phase, thereby enhancing the efficiency of the ultrafiltration system.

Model supports asymmetric regulation across the intercellular junction for collective cell polarization.

Symmetry breaking, which is ubiquitous in biological cells, functionally enables directed cell movement and organized embryogenesis. Prior to movement, cells break symmetry to form a well-defined cell front and rear in a process called polarization. In developing and regenerating tissues, collective cell movement requires the coordination of the polarity of the migration machineries of neighboring cells. Though several works shed light on the molecular basis of polarity, fewer studies have focused on the regulation across the cell-cell junction required for collective polarization, thus limiting our ability to connect tissue-level dynamics to subcellular interactions. Here, we investigated how polarity signals are communicated from one cell to its neighbor to ensure coordinated front-to-rear symmetry breaking with the same orientation across the group. In a theoretical setting, we systematically searched a variety of intercellular interactions and identified that co-alignment arrangement of the polarity axes in groups of two and four cells can only be achieved with strong asymmetric regulation of Rho GTPases or enhanced assembly of complementary F-actin structures across the junction. Our results held if we further assumed the presence of an external stimulus, intrinsic cell-to-cell variability, or larger groups. The results underline the potential of using quantitative models to probe the molecular interactions required for macroscopic biological phenomena. Lastly, we posit that asymmetric regulation is achieved through junction proteins and predict that in the absence of cytoplasmic tails of such linker proteins, the likeliness of doublet co-polarity is greatly diminished.

PERK transition–induced directional mode switching promotes epithelial tumor cell migration

Increasing evidence suggests that tumor cells exhibit extreme plasticity in migration modes in order to adapt to microenvironments. However, the underlying mechanism for governing the migration mode switching is still unclear. Here, we revealed that epithelial tumor cells could develop a stable directional mode driven by hyperactivated ERK activity. This highly activated and dynamically changing ERK activity, called pERK transition, is crucial for inducing the switch from pauses state to directional movement and is also necessary for maintaining epithelial tumor cells in the directional mode. PERK transition integrated pERK surf, the dynamic and localized ERK activity at the leading edge. The sequential activation of RhoA and Rac1 by pERK transition played critical roles in generation of pERK surf activity through a movement feedback mechanism. PERK transition activity converted the orderly collective migration into the disordered dispersal movement, enhanced the invasiveness of epithelial tumor cells, and promoted their metastasis in immune-deficient mice. These findings revealed that the exquisite spatiotemporal organization of ERK activity orchestrates migration and invasion of tumor cells and provide evidence for the mechanism underlying migration mode switching in epithelial tumor cells.

Survivin modulates stiffness-induced vascular smooth muscle cell motility.

Arterial stiffness is a key contributor to cardiovascular diseases, including atherosclerosis, restenosis, and coronary artery disease, it has been characterized to be associated with the aberrant migration of vascular smooth muscle cells (VSMCs). However, the underlying molecular mechanisms driving VSMC migration in stiff environments remain incompletely understood. We recently demonstrated that survivin, a member of the inhibitor of apoptosis protein family, is highly expressed in both mouse and human VSMCs cultured on stiff polyacrylamide hydrogels, where it modulates stiffness-mediated cell cycle progression and proliferation. However, its role in stiffness-dependent VSMC migration remains unknown. To assess its impact on migration, we performed time-lapse video microscopy on VSMCs seeded on fibronectin-coated soft and stiff polyacrylamide hydrogels, mimicking the physiological stiffness of normal and diseased arteries, with either survivin inhibition or overexpression. We observed that VSMC motility increased under stiff conditions, while pharmacologic or siRNA-mediated inhibition of survivin reduced stiffness-stimulated migration to rates similar to those observed under soft conditions. Further investigation revealed that cells on stiff hydrogels exhibited greater directional movement and robust lamellipodial protrusion compared to those on soft hydrogels. Interestingly, survivin-inhibited cells on stiff hydrogels showed reduced directional persistence and lamellipodial protrusion compared to control cells. We also examined whether survivin overexpression alone is sufficient to induce cell migration on soft hydrogels, and found that survivin overexpression modestly increased cell motility and partially rescued the lack of directional persistence compared to GFP-expressing control VSMCs on soft hydrogels. In conclusion, our findings demonstrate that survivin plays a key role in regulating stiffness-induced VSMC migration, suggesting that targeting survivin and its signaling pathways could offer therapeutic strategies for addressing arterial stiffness in cardiovascular diseases.

Constructing Ultra-High Current Direct-Current Tribo-Photovoltaic Nanogenerators via Cu/Perovskite Schottky Junction.

Perovskite-based direct-current triboelectric nanogenerators (DC-TENGs) leveraging the tribo-photovoltaic effect have garnered significant attention for their ability to simultaneously harvest mechanical and solar energy, effectively enhancing the output performance of DC-TENGs. Herein, we innovatively construct a rolling-mode Cu/ternary cation perovskite (FA0.945MA0.025Cs0.03Pb(I0.975Br0.025)3) Schottky junction DC-TENGs with ultrahigh current output and excellent operational stability. The Cu/perovskite Schottky junction ensures the formation of an internal electric field, promoting carrier separation and directional movement for a stable DC output. Under AM 1.5 G illumination, the DC-TENG achieves a short-circuit current (Isc) and current density of 408 μA and 27.2 A/m2, respectively, marking a 119 times increase as compared to dark conditions and the highest reported Isc for perovskite DC-TENGs. With over 30 min of operation, the current output remains stable. The DC-TENGs exhibit promising applications in temperature and humidity sensing and self-powered photodetection. Furthermore, by adjusting the light power density, the optimal internal output impedance of DC-TENGs can be tuned broadly from 0.9 to 132 kΩ, offering great potential for impedance matching in self-powered microelectronic components. This research provides insights into the development of multifunctional DC-TENG devices with coupled mechanical and solar energy, expanding the application scope of perovskite materials and devices.

Granular metamaterials with dynamic bond reconfiguration.

Biological materials dynamically reconfigure their underlying structures in response to stimuli, achieving adaptability and multifunctionality. Conversely, mechanical metamaterials have fixed interunit connections that restrict adaptability and reconfiguration. This study introduces granular metamaterials composed of discrete bimaterial structured particles that transition between assembled and unassembled states through mechanical compression and thermal stimuli. These materials enable dynamic bond reconfiguration, allowing reversible bond breaking and formation, similar to natural systems. Leveraging their discrete nature, these materials can adaptively reconfigure their shape and respond dynamically to varying conditions. Our investigations reveal that these granular metamaterials can substantially alter their mechanical properties, like compression, shearing, and bending, offering tunable mechanical characteristics across different states. Furthermore, they exhibit collective behaviors like directional movement, object capture, transportation, and gap crossing, showcasing their potential for reprogrammable functionalities. This work highlights the dynamic reconfigurability and robust adaptability of granular metamaterials, expanding their potential in responsive architecture and autonomous robotics.

Gradient Nonwettability Controls Water-Film Flowing Features.

The flow of the water film on solid surface depended on the film Reynolds number and wind speed. Moreover, environmental factors had an impact on the flow process. This study explored how surface wettability impacts the stability and detachment of water film under varying conditions. Superhydrophobic surface played a critical role in speeding up the detachment of water film, especially under conditions of strong wind and specific flow dynamics, such as a wind speed of 19 m/s and a Reynolds number of 83. The efficiency in water removal was due to a combination of forces: capillary action, which pulls the water into smaller areas, reduced surface tension, and decreased adhesion between the liquid and surface. These factors worked together to shrink the area of contact, allowing the film to break and detach more easily. The findings suggested that enhancing nonwettability can improve water removal efficiency, with potential applications in fields like aerospace. Furthermore, additional trials across varying wind speeds and Reynolds numbers consistently supported the superior performance of superhydrophobic surface in driving rapid water-film detachment. To advance this effect, a gradient nonwetting surface was introduced, specifically engineered within the superhydrophobic regime, to amplify the velocity of film separation. This design innovation leveraged variations in surface energy across the gradient, which fostered directional water-film movement and accelerated detachment. A comprehensive analysis of the underlying physical mechanisms further elucidated its potential in enhancing water-shedding applications across a range of environmental conditions.

Movement as an activity vs. movement as an event: Czech translation correspondences of English walk in locative inversion constructions

The article shows that the verb ‘kráčet’ predominantly appears as a translation correspondence of ‘walk’ used in subject-verb inversion constructions lacking overt directionality of movement. In these situations, the movement has the status of an activity. The verb ‘jít’ and its derivatives predominantly appear as translation correspondences of ‘walk’ used in subject-verb inversion constructions involving overt directionality of movement. In these situations, the movement represents an event. The verbs’ propensity to be employed in the types of motion situations in question is underlain by differences in the degrees of the salience of their manner and path schemata.