Spatial Position Research Articles

Cross-sectional and retrospective study regarding the changes in the spatial position of the hyoid bone and upper airways before and after orthodontic therapy in developing patients with normocclusion.

The objective was to study the effect of orthodontic therapy regarding the position of the hyoid bone and upper airways in nighty-one 6-21 year-old Caucasian patients with normoclussion. Nineteen variables were analyzed by teleradiography. The differences were analyzed with the ANOVA test of repeated measures with an intra-group factor for two occasions. The statistical analysis revealed a greater influence on the variables Hy-MP (12.3 vs 14.2), Hps-C3 (25.2 vs 28.1), Hpi-C3 (28.8 vs 35.5), H°-C3 (14.4 vs 12.7), Hps-Rg (36.0 vs 42.7), Hpi-Rg (34.1 vs 39.7), USP (16.2 vs 20.2), MPP (12.9 vs 14.8), C3P (10.6 vs 12.8), PNS-Ba (43.5 vs 66.5), PtV-Ad (12.0 vs 17.1) and PtM-Ba (33.9 vs 35.9), and Ad2-SO (24.16 vs 20.87). Significant differences were observed between most of the airway and hyoid bone variables before and after orthodontic treatment in our Spanish pediatric population, especially in the nasopharynx.

Contextual cueing—Eye movements in rotated and recombined displays

Contextual cueing leads to improved efficiency in visual search resulting from the extraction of spatial regularities in repeated visual stimuli. Previous research has demonstrated the independent contributions of global configuration and spatial position to contextual cueing. The present study aimed to investigate whether learned spatial configuration or individual locations would elicit fixation patterns resembling those observed in the original displays. We found that search guidance based on either local or global spatial context, by combining distractor locations from two learned displays or rotating displays, kept not only search time facilitation intact, in agreement with previous studies, but also enabled search with less fixations and more direct scan paths to the target. Fixation distribution maps of recombined or rotated displays were more similar to the original displays than random new displays. However, for rotated displays this was only true when the rotation angle was taken into account. Overall, this shows an astonishingly flexible use of the oculomotor system for search in incompletely repeated displays.

DNA Origami‐Directed Self‐Assembly of Gold Nanospheres for Plasmonic Metasurfaces

AbstractPlasmonic nanostructures are frequently utilized to create metasurfaces with a large variety of optical effects. Control over shape and positioning of the nanostructures is key to the function of such plasmonic metasurfaces. Next to lithographic means, directed self‐assembly is a viable route to create plasmonic structures on surfaces with the necessary precision. Here, a combined approach of DNA origami self‐assembly and electron beam lithography is presented for determinate positioning of gold nanospheres on a SiO2 surface. First, DNA origami structures bind to the electron beam‐patterned substrate and subsequently, gold nanoparticles attach to a defined binding site on the DNA origami structure via DNA hybridization. A sol‐gel reaction is then used to grow a silica layer around the DNA, thereby increasing the stability of the self‐assembled metasurface. A mean yield of 74% of single gold nanospheres is achieved located at the determinate positions with a spatial position accuracy of 9 nm. Gold nanosphere dimers and trimers are achieved with a rate of 65% and 60%, respectively. The applicability of this structuring method is demonstrated by the fabrication of metasurfaces whose optical response can be tuned by the polarization of the incoming and the scattered light.

Self-Perceptional Soft Robotics by a Dielectric Elastomer.

Soft robotics has been a rapidly growing field in recent decades due to its advantages of softness, deformability, and adaptability to various environments. However, the separation of perception and actuation in soft robot research hinders its progress toward compactness and flexibility. To address this limitation, we propose the use of a dielectric elastomer actuator (DEA), which exhibits both an actuation capability and perception stability. Specifically, we developed a DEA array to localize the 3D spatial position of objects. Subsequently, we integrate the actuation and sensing properties of DEA into soft robots to achieve self-perception. We have developed a system that integrates actuation and sensing and have proposed two modes to achieve this integration. Furthermore, we demonstrated the feasibility of this system for soft robots. When the robots detect an obstacle or an approaching object, they can swiftly respond by avoiding or escaping the obstacle. By eliminating the need for separate perception and motion considerations, self-perceptional soft robots can achieve an enhanced response performance and enable applications in a more compact and flexible field.

MR2CPPIS: Accurate prediction of protein–protein interaction sites based on multi-scale Res2Net with coordinate attention mechanism

Proteins play a vital role in various biological processes and achieve their functions through protein–protein interactions (PPIs). Thus, accurate identification of PPI sites is essential. Traditional biological methods for identifying PPIs are costly, labor-intensive, and time-consuming. The development of computational prediction methods for PPI sites offers promising alternatives. Most known deep learning (DL) methods employ layer-wise multi-scale CNNs to extract features from protein sequences. But, these methods usually neglect the spatial positions and hierarchical information embedded within protein sequences, which are actually crucial for PPI site prediction. In this paper, we propose MR2CPPIS, a novel sequence-based DL model that utilizes the multi-scale Res2Net with coordinate attention mechanism to exploit multi-scale features and enhance PPI site prediction capability. We leverage the multi-scale Res2Net to expand the receptive field for each network layer, thus capturing multi-scale information of protein sequences at a granular level. To further explore the local contextual features of each target residue, we employ a coordinate attention block to characterize the precise spatial position information, enabling the network to effectively extract long-range dependencies. We evaluate our MR2CPPIS on three public benchmark datasets (Dset 72, Dset 186, and PDBset 164), achieving state-of-the-art performance. The source codes are available at https://github.com/YyinGong/MR2CPPIS.

Analysis of the Rigid Foldability of Origami Patterns Based on Spatial Positions of Creases

Abstract Rigid foldability is a special property of rigid origami patterns, where each origami plane remains undeformed during continuous movement along the predetermined crease. Current research on the rigid foldability of origami patterns mainly focuses on kinematics, while less attention is paid to factors that cause deformation of the folding plane. Whether the relative spatial position of adjacent creases has been changed is a critical factor that influences the state (rigid or deformed) of the folding plane between the two adjacent creases during the folding process. This study considered two factors (linear relationship and Euclidean distance) to measure the changes in the spatial positions of creases, explored the relationship between the two factors and rigid folding, and identified deformation forms that affects rigid foldability. First, the origami pattern was regarded as a linkage mechanism, and the linear relationship between creases was determined from the single-vertex origami unit forming this origami structure. Then, the geometric parameters of the origami pattern were used to calculate the Euclidean distance between two points on adjacent creases during the folding process. If the linear relationship and Euclidean distance always remain the same, the origami pattern has rigid foldability. Based on changes in Euclidean distance, this method can also help determine the main deformation of non-rigidly foldable origami patterns. In addition, it further provides a novel approach for determining the layout of the crease position and the judgment of rigid foldability during origami-inspired mechanism design.

Time and Distance Perception in Highly Dynamic Environments

Abstract Space- and time-based tasks, like flying airplanes, driving cars, or the manual controlled rendezvous and docking of spacecrafts can be very demanding for pilots, drivers, or astronauts, depending on selected trajectories, approaching speeds, or distracting information. One characteristic of highly dynamic environments is that persons have to consider their spatial position in relation to surrounding elements based on passing time, detected speed, and trajectories to avoid collisions with other objects. An inadequate perception of the own position in relation to other objects and passing time can lead to impaired decision-making processes, resulting in errors or collisions. A framework for the explanation of cognitive processes involved in perception, anticipation, and decision-making in dynamic environments is provided by the concept of situation awareness. Based on this framework persons must perceive relevant elements, integrate them in a coherent mental representation and anticipate the development of the current situation in the near future, to plan safe upcoming maneuvers. Thus, for safe maneuvers anticipation processes are playing a major role in decision-making and action selection. In this paper it is proposed that time and distance perceptions are central features of anticipation processes in dynamic situations. It is suggested to combine theories like the attentional-gate model and time-to-contact with the framework of situation awareness to explain anticipation processes in dynamic environments. The major aim is to develop precise cognitive models of persons acting in dynamic situations. Such cognitive models can be the basis for the development and parameterization of assistance systems, supporting anticipation in dynamic environments.

Experimental study on the spray characteristics of an internal-mixing gas-liquid injector

To determine the spray characteristics of internal-mixing gas-liquid injector under various operating conditions, the experimental facilities for spraying are established. By means of high-speed camera, laser particle size analyzer and PIVlab, the effects of gas and liquid flow conditions on the spray characteristics, such as position of jet impingement, spray angle, breakup length, velocity distribution and droplet size, have been investigated in detail. Experimental results demonstrated that there are two types of atomization for this injector, namely impact atomization and aerodynamic atomization. The impingement position of the liquid jets is outside of the injector exit. Alternatively, no impingement occurs between the jets. The spray angle increases with the increase of liquid flow rate, and decreases with the increase of gas flow rate. The breakup length decreases with the increase of the liquid or gas flow rate. The higher the liquid flow rate, the greater the velocity distributed along the axial and radial direction. However, the effect of gas flow rate on the velocity along the axial and radial directions acts differently at different spatial position. An increase in the liquid flow rate causes the droplet diameter to increase first and then decrease. The droplet size will decrease when the gas-liquid momentum ratio increases.

Change in the Spatial Position of Mini-implants During Distal Movement of the Entire Maxillary Dentition: An Observational CBCT Study.

To determine the change in the sagittal and vertical position of the mini-implant placed in the maxilla during distal movement of the entire maxillary dentition. Twenty eight mini-implants, fourteen on each side were evaluated in young healthy patients in the age group of 15 years to 25 years. Distal movement of the entire maxillary arch was performed with 1.2 mm x 8 mm stainless steel mini-implants on 0.018" x 0.025" stainless steel wire. CBCT were taken at the start of (T1) and at the end of six months (T2) of distal movement of the maxillary teeth. The vertical and sagittal angulation of the mini-implant was measured at T1 and T2. The linear distance between the mini-implant and the alveolar crest, the maxillary sinus, the maxillary second premolar and the maxillary first permanent molar were measured. The change in angulation and the linear displacement of the mini-implant were evaluated in the vertical and sagittal plane. Wilcoxon signed rank test was performed to determine if there was a statistically significant change in the position of the mini-implant. Vertically, there was a significant change in the linear distance between the miniimplant and the alveolar crest on the right side (p≤.006) and the mini-implant and the maxillary sinus on the left side (p≤.003). Sagittally, there was a statistically significant rotation of the miniimplant occlusally (left side p≤.004 and right side p≤.002). The head and tip of the mini-implant were displaced towards the maxillary second premolar and away from the maxillary first permanent molar respectively. There was a significant relative displacement of the mini-implant anteriorly away from the maxillary first permanent molar (left side p≤.026 and right side p≤.041)and closer to the maxillary second premolar (left side: p≤..011 and right side: p≤.002). There was a statistically and clinically significant rotation of the mini-implant in the vertical and sagittal direction during distal movement of the entire maxillary teeth. The linear displacement of the mini-implant was more pronounced in the sagittal direction compared to the vertical direction.

Multimodal aircraft flight altitude inversion from SDGSAT-1 thermal infrared data

Accurately detecting and localizing high-speed aircraft is significant for monitoring global flight activities, conducting searches, and performing emergency rescues. Typically, the spatial position of an air target is obtained through active communication or multi-satellite observation. Here, we propose a multimodal flight altitude inversion method using a single thermal infrared payload (SDGSAT-1 TIS). Space-based longwave thermal infrared is a passive detection method that can measure the surface thermal radiation of objects and capture radiation differences caused by flying aircraft against the background, thereby providing an opportunity for their detection and location. Considering geographic location, time, climate, and aircraft size, we establish a framework to integrate the radiation transmission model with three-spectral-band remote sensing data. This proposed framework elucidates the relationship between flight altitude and top-of-atmosphere radiance, realizing the inversion from thermal infrared remote sensing images to altitude. Validated on 100 aircraft, the proposed framework achieved an average altitude measurement accuracy of 0.508 km compared with Flightradar24. This research provides a unique solution for the all-time passive localization of air targets.

An Artificial Liquid–Liquid Phase Separation-Driven Silk Fibroin-Based Adhesive for Rapid Hemostasis and Wound Sealing

The powerful adhesion systems of marine organisms have inspired the development of artificial protein-based bioadhesives. However, achieving robust wet adhesion using artificial bioadhesives remains technically challenging because the key element of liquid–liquid phase separation (LLPS)-driven complex coacervation in natural adhesion systems is often ignored. In this study, mimicking the complex coacervation phenomenon of marine organisms, an artificial protein-based adhesive hydrogel (SFG hydrogel) was developed by adopting the LLPS-mediated coacervation of the natural protein silk fibroin (SF) and the anionic surfactant sodium dodecylbenzene sulfonate (SDBS). The assembled SF/SDBS complex coacervate enabled precise spatial positioning and easy self-adjustable deposition on irregular substrate surfaces, allowing for tight contact. Spontaneous liquid-to-solid maturation promoted the phase transition of the SF/SDBS complex coacervate to form the SFG hydrogel in situ, enhancing its bulk cohesiveness and interfacial adhesion. The formed SFG hydrogel exhibited intrinsic advantages as a new type of artificial protein-based adhesive, including good biocompatibility, robust wet adhesion, rapid blood-clotting capacity, and easy operation. In vitro and in vivo experiments demonstrated that the SFG hydrogel not only achieved instant and effective hemostatic sealing of tissue injuries but also promoted wound healing and tissue regeneration, thus advancing its clinical applications. Statement of significanceMarine mussels utilize the liquid–liquid phase separation (LLPS) strategy to induce the supramolecular assembly of mussel foot proteins, which plays a critical role in strong underwater adhesion of mussel foot proteins. Herein, an artificial protein-based adhesive hydrogel (named SFG hydrogel) was reported by adopting the LLPS-mediated coacervation of natural protein silk fibroin (SF) and anionic surfactant sodium dodecylbenzene sulfonate (SDBS). The assembled SFG hydrogel enabled the precise spatial positioning and easy self-adjustable deposition on substrate surfaces with irregularities, allowing tight interfacial adhesion and cohesiveness. The SFG hydrogel not only achieved instant and effective hemostatic sealing of tissue injuries but also promoted wound healing and tissue regeneration, exhibiting intrinsic advantages as a new type of artificial protein-based bioadhesives.

[Assessment of auditory perception of children with single-sided deafness after cochlear implantation].

Unilateral deafness will lead to the decline of children's speech recognition rate, language development retardation and spatial positioning ability, which will have many adverse effects on children's life and study. Cochlear implantation can help children rebuild binaural hearing, and systematic audiological evaluation after operation is particularly important for clinicians to evaluate the hearing recovery of children. In this study, a variety of commonly used audiological evaluation, testing processes and methods after cochlear implantation in children with unilateral deafness are described in detail, and the related research status and results are summarized.

DEM-CFD coupling verification and analysis of a sand control medium structure with weakened particle blockage performance

This study addresses the prominent contradiction between solid phase control and production capacity release during the exploitation of natural gas hydrate in fine silty sand reservoirs. A novel mechanical sand control medium structure incorporating the filter slots/nets (referred to as the sand control component, SCC) and the cylindrical/spherical structures placed outside the SCC (referred to as the blockage control component, BCC) has been designed. Concurrently, a DEM-CFD sand-retaining numerical model is developed, and the traditional/new structural screens have been separately simulated for sand retention. Through the spatiotemporal evolution of DEM and CFD characteristic model parameters during simulation, the blockage mechanism and characteristics of fine particles are obtained. Compared to the traditional screen structure without a BCC, the existence of a BCC effectively evacuates particles within the accumulated sand body towards the wellbore, reducing the compactness and stress level within the sand body; while the pressure loss generated by fluid flow through the sand body decreases, significantly improving the porous and permeable conditions within the sand body. The degree of influence of a BCC on different DEM and CFD characteristic model parameters is further determined and ranked. A comprehensive blockage optimization index is introduced to quantify the performance of weakening sand blockage by the BCC and optimize the spatial position of the BCC. The BCC enables the design of sand control schemes to reduce the filter aperture of the SCC to a sufficiently small size to effectively control the fine silty sand production, while avoiding gradually severe blockage as production progresses.

A Ligand-Directed Spatial Regulation to Structural and Functional Tunability in Aggregation-Induced Emission Luminogen-Functionalized Organic-Inorganic Nanoassemblies.

Aggregation-induced emission luminogen (AIEgen)-functionalized organic-inorganic hybrid nanoparticles (OINPs) are an emerging category of multifunctional nanomaterials with vast potential applications. The spatial arrangement and positioning of AIEgens and inorganic compounds in AIEgen-functionalized OINPs determine the structures, properties, and functionalities of the self-assembled nanomaterials. In this work, a facile and general emulsion self-assembly tactic for synthesizing well-defined AIEgen-functionalized OINPs is proposed by coassembling alkane chain-functionalized inorganic nanoparticles with hydrophobic organic AIEgens. As a proof of concept, the self-assembly and structural evolution of plasmonic-fluorescent hybrid nanoparticles (PFNPs) from concentric circle to core shell and then to Janus structures is demonstrated by using alkane chain-modified AuNPs and AIEgens as building blocks. The spatial position of AuNPs in the signal nanocomposite is controlled by varying the alkane ligand length and density on the AuNP surface. The mechanism behind the formation of various PFNP nanostructures is also elucidated through experiments and theoretical simulation. The obtained PFNPs with diverse structures exhibit spatially tunable optical and photothermal properties for advanced applications in multicolor and multimode immunolabeling and photothermal sterilization. This work presents an innovative synthetic approach of constructing AIEgen-functionalized OINPs with diverse structures, compositions, and functionalities, thereby championing the progressive development of these OINPs.

Research on Human Pose Estimation Model Based on Long-Range Fine-Grained Modeling

To address the issues of lacking long-range spatial position learning ability and excessive loss of fine-grained feature information during spatial feature pooling in human pose estimation models, a novel human pose estimation model based on the Yolopose network is proposed. Firstly, an enhanced coordinate attention module is introduced and embedded into the backbone network to endow the model with long-range spatial position modeling capability. Secondly, a fine-grained cascaded spatial pyramid pooling module is proposed to mitigate the loss of fine-grained feature information caused by spatial feature pooling. Finally, an implicit knowledge learning module is incorporated to reduce the model parameter count and enhance the model's capability for multi-task joint optimization.

Control over Anion Coordination on Pd(II), Cu(I), and Ag(I) with Regioisomeric Phosphine-Carboxylate Ligands.

The coordination of anionic donors is involved at various stages of catalytic cycles in transition-metal catalysis, but control over the spatial positioning of anions around a metal center is a challenge in coordination chemistry. Here we show that regioisomeric phosphine-carboxylate ligands provide spatial anion control on palladium(II) centers by favoring either κ2, cis-κ1, or trans-κ1 coordination of the carboxylate donor. Additionally, the palladium(II) carboxylates, which contain a methyl donor, upon protonation, deliver metal-alkyl complexes that feature a coordinated carboxylic acid. Such complexes can be considered as models for the minima that follow the concerted metalation-deprotonation transition state for C-H activation. The predictability of the coordination modes is further demonstrated on silver(I) and copper(I) centers, for which less common structures of mononuclear and binuclear complexes can be obtained by using spatial anion control. Our results demonstrate the potential for spatial control over carboxylate anions in coordination chemistry.

Effect of Intake Acoustic Reflection on Blade Vibration Characteristics

Recent studies in turbomachinery have shown that the phase of acoustic wave reflection within an intake can have either positive or negative effects on the aeroelastic stability of fan rotor blades. However, the typical flow structures, such as the shock wave, within rotor blade passages with acoustic wave reflection remain unclear. The aim of this research was to address this gap by investigating how these flow structures impact blade aeroelastic stabilities with acoustic wave reflections. The focus of this study was the NASA Rotor 67 blade with an extended intake. Moreover, a bump is incorporated on the shroud at different distances from the fan to reflect acoustic waves of varying phases. Utilizing the energy method, variations in the aerodynamic work density on blade surfaces were calculated under different phases of reflected acoustic waves. Analysis indicates that the spatial position of the shock wave undergoes periodic changes synchronized with the phase of acoustic reflection, marking the first instance of such an observation. This synchronization is identified as the primary factor causing variations in the aeroelastic stability of blades due to acoustic wave reflection, contributing to a deeper understanding of the mechanism behind acoustic flutter. The acoustic–vortex coupling at the blade tip leads to unpredictable variations in unsteady pressures on the blade suction surface, although its effect on blade aeroelastic stabilities is relatively limited compared to that of the shock wave.

Vehicle vibration test platform structure design and control strategy optimization

AbstractFor the needs of vehicle vibration test platform with high precision, large load capacity and fast response, the three‐dimensional model design and analysis of vehicle vibration test platform are carried out; in order to improve the motion performance of the platform, a vibration test plat‐form control strategy combining hybrid heuristic algorithm and PID control is proposed. Based on the designed 3D model parameters, the single‐channel mathematical model of the servo‐electric cylinder is derived and a hybrid heuristic algorithm PID optimization model is established to compare and analyze the control performance of the platform with the Ziegler‐Nichols method PID. The results show that the step system overshoot is 3.80% and the dynamic performance of the system is significantly improved when the hybrid heuristic algorithm PID control is used. The simulation system model of vehicle vibration test platform control is established, and the operation results show that the platform is closer to the input signal in the spatial position change curve when the hybrid heuristic algorithm PID control is used. Its maximum displacement error is 0.09 mm, and the motion accuracy of the system is improved by 61% compared with the Ziegler‐Nichols method PID control.

Gold Deposits Related to the Island Arc Formations and Ophiolitic Complexes of Eastern Cuba: A Review

Several gold deposits in the eastern region of Cuba are genetically related to the island arc- and the ophiolitic complex formation. These have been studied and exploited since the time of the Spanish colonization in the mid-sixteenth century. These deposits belong to the Aguas Claras-Guajabales mineral field in the Holguín Province (Cuba) and lie in an elongated zone approximately 15 km in length. The object of this work is to make a methodical, detailed, and chronological review of the geological and mining work carried out in this region, as well as highlight the degree of the previously achieved studies. To realize this, an extensive bibliographic review of all available data, including published reports and articles, as well as unpublished material, was carried out. Moreover, ore mineralogy and petrography were reviewed by thin section analyses from samples from these deposits by petrographic and scanning electron microscopy. The results obtained from this study highlight that the gold mineralization in that area is closely linked to metasomatic processes produced by the circulation of hydrothermal fluids that affected the different volcanic and ultramafic rocks. This study shows that the highest gold contents observed are controlled by the contacts between the different host lithologies with high rheological contrasts. The presence of different alteration styles such as serpentinization, listvenitization, rodingitization, and propylitization have played a primary role in the deposition of gold during mineralization processes. This work could be a very useful exploration guide for future research in this region, as it provides a useful and practical compilation of the characteristics of the mineralization and alteration styles, as well as a precise indication of the spatial position, thicknesses, and contents of the gold-rich horizons.

How to resolve the contradiction between driving safety and lighting energy conservation in a highway tunnel? − An experiment on linear guiding system

High rates of traffic accidents and lighting energy consumption are significant problems in highway tunnels. To address these problems, this study proposes a linear guiding system that uses line-shaped visual guiding facilities to improve the local luminance and contrast, and outlines the tunnel contour and road alignment. In addition, the principle, function, setting method, and composition of the linear guiding system are discussed. Using the existing highway tunnels as prototypes, we built simulation scenarios with different luminance and conducted driving simulation experiments and questionnaire surveys. We analysed the human factor demands of tunnel driving, studied the change rule of various human factor indicators under different luminance levels, and comprehensively evaluated the impact of linear guiding system on driving safety from multiple perspectives of the driver’s vision, psychology, and behaviour. We introduce the concept of equivalent luminance, quantify the impact of linear guiding system on the driver, and explore the role of linear guiding system in energy conservation. The results showed that the linear guiding system has a positive effect on driver vision, psychology, and behaviour, particularly in low-luminance environments. A linear guiding system can optimise a driver’s visual reference frame, enhance driver visual perception in a tunnel environment, and alleviate driver tension. It helps drivers to accurately perceive their own spatial position and speed, providing a good sense of position, speed, and comfort. A 2.3 cd/m2 luminance highway tunnel with a linear guiding system is equivalent to a 4 cd/m2 luminance traditional tunnel. For highway tunnels with luminance values of 4, 5, 6, and 7 cd/m2, the equivalent luminance values of the linear guiding system are 1.7, 1.8, 1.8, and 2.1 cd/m2 respectively, which can reduce the energy consumption by 30–42 %.