scholarly journals Mechanosensitivity of amoeboid cells crawling in 3D

2021 ◽  
Author(s):  
Florian Gaertner ◽  
Patricia Reis-Rodrigues ◽  
Ingrid de Vries ◽  
Miroslav Hons ◽  
Juan Aguilera ◽  
...  
Keyword(s):  
Three Dimensional ◽  
The Body ◽  
Three Dimensions ◽  
Cortical Actin ◽  
Actin Networks ◽  
Motile Cells ◽  
Spatio Temporal ◽  
Adhesive Interactions ◽  
The Right ◽  
Amoeboid Cells

Efficient immune-responses require migrating leukocytes to be in the right place at the right time. When crawling through the body amoeboid leukocytes must traverse complex three-dimensional tissue-landscapes obstructed by extracellular matrix and other cells, raising the question how motile cells adapt to mechanical loads to overcome these obstacles. Here we reveal the spatio-temporal configuration of cortical actin-networks rendering amoeboid cells mechanosensitive in three-dimensions, independent of adhesive interactions with the microenvironment. In response to compression, Wiskott-Aldrich syndrom protein (WASp) assembles into dot-like structures acting as nucleation sites for actin spikes that in turn push against the external load. High precision targeting of WASp to objects as delicate as collagen fibers allows the cell to locally and instantaneously deform its viscoelastic surrounding in order to generate space for forward locomotion. Such pushing forces are essential for fast and directed leukocyte migration in fibrous and cell-packed tissues such as skin and lymph nodes.

scholarly journals Actin-based protrusions of migrating neutrophils are intrinsically lamellar and facilitate direction changes

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Lillian K Fritz-Laylin ◽  
Megan Riel-Mehan ◽  
Bi-Chang Chen ◽  
Samuel J Lord ◽  
Thomas D Goddard ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Light Sheet ◽  
Time Lapse ◽  
Three Dimensions ◽  
Cortical Actin ◽  
Linear Arrangement ◽  
Collagen Matrices ◽  
Flat Surfaces ◽  
Actin Networks ◽  
Light Sheet Microscopy

Leukocytes and other amoeboid cells change shape as they move, forming highly dynamic, actin-filled pseudopods. Although we understand much about the architecture and dynamics of thin lamellipodia made by slow-moving cells on flat surfaces, conventional light microscopy lacks the spatial and temporal resolution required to track complex pseudopods of cells moving in three dimensions. We therefore employed lattice light sheet microscopy to perform three-dimensional, time-lapse imaging of neutrophil-like HL-60 cells crawling through collagen matrices. To analyze three-dimensional pseudopods we: (i) developed fluorescent probe combinations that distinguish cortical actin from dynamic, pseudopod-forming actin networks, and (ii) adapted molecular visualization tools from structural biology to render and analyze complex cell surfaces. Surprisingly, three-dimensional pseudopods turn out to be composed of thin (<0.75 µm), flat sheets that sometimes interleave to form rosettes. Their laminar nature is not templated by an external surface, but likely reflects a linear arrangement of regulatory molecules. Although we find that Arp2/3-dependent pseudopods are dispensable for three-dimensional locomotion, their elimination dramatically decreases the frequency of cell turning, and pseudopod dynamics increase when cells change direction, highlighting the important role pseudopods play in pathfinding.

scholarly journals Three-dimensional actin-based protrusions of migrating neutrophils are intrinsically lamellar and facilitate direction changes

2017 ◽  
Author(s):  
Lillian K. Fritz-Laylin ◽  
Megan Riel-Mehan ◽  
Bi-Chang Chen ◽  
Samuel J. Lord ◽  
Thomas D. Goddard ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Light Sheet ◽  
Time Lapse ◽  
Three Dimensions ◽  
Cortical Actin ◽  
Linear Arrangement ◽  
Collagen Matrices ◽  
Flat Surfaces ◽  
Actin Networks ◽  
Light Sheet Microscopy

AbstractLeukocytes and other amoeboid cells change shape as they move, forming highly dynamic, actin-filled pseudopods. Although we understand much about the architecture and dynamics of thin lamellipodia made by slow-moving cells on flat surfaces, conventional light microscopy lacks the spatial and temporal resolution required to track complex pseudopods of cells moving in three dimensions. We therefore employed lattice light sheet microscopy to perform three-dimensional, time-lapse imaging of neutrophil-like HL-60 cells crawling through collagen matrices. To analyze three-dimensional pseudopods we: (i) developed fluorescent probe combinations that distinguish cortical actin from dynamic, pseudopod-forming actin networks, and (ii) adapted molecular visualization tools from structural biology to render and analyze complex cell surfaces. Surprisingly, three-dimensional pseudopods turn out to be composed of thin (<0.75 μm), flat sheets that sometimes interleave to form rosettes. Their laminar nature is not templated by an external surface, but likely reflects a linear arrangement of regulatory molecules. Although we find that pseudopods are dispensable for three-dimensional locomotion, their elimination dramatically decreases the frequency of cell turning, and pseudopod dynamics increase when cells change direction, highlighting the important role pseudopods play in pathfinding.

The three-dimensional stable mandibular landmarks in patients between the ages of 12.5 to 17.1 years

2020 ◽  
Author(s):  
Gui Chen ◽  
Mona Al Awadi ◽  
David William Chambers ◽  
Manuel O Lagravère-Vich ◽  
Tianmin Xu ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Growth Period ◽  
Mandibular Canal ◽  
Mental Foramen ◽  
Three Dimensions ◽  
Head Orientation ◽  
Facial Growth ◽  
Linear Distance ◽  
The Right ◽  
Stable Structures

Abstract Background: With the aid of implants, Björk identified the two-dimensional mandibular stable structures in cephalogram during facial growth. However, we don't know the three-dimensional stable structures exactly. The purpose of this study was to identify the most stable mandibular landmarks in growing patients using three-dimensional images.Methods: The sample was comprised of two cone-beam computed tomography (CBCT) scans taken about 4.6 years apart in 20 growing patients between the ages of 12.5 (T1) to 17.1 years (T2). After head orientation, landmarks were located on the chin (Pog), internal symphysis (Points C, D and E), and mandibular canals, which included the mental foramina (MF and MFA) and mandibular foramina (MdF). The linear distance change between Point C and these landmarks was measured on each CBCT to test stability through time. The reliability of the suggested stable landmarks was also evaluated. Results: The total distance changes between Point C and points D, E, Pog, MF, and MFA were all less than 1.0 mm from T1 to T2. The reliability measures of these landmarks, which were measured by the Cronbach alpha, were above 0.94 in all three dimensions for each landmark. From T1 to T2, distance changes from Point C to the right and left mandibular foramina were respectively 3.39±3.29 mm and 3.03±2.83 mm. Conclusions: During a growth period that averaged 4.6-years, ranging from 11.2 to 19.8 years, the structures that appeared relatively stable and could be used in mandibular regional superimposition included Pog, landmarks on the inferior part of the internal symphysis, and the mental foramen. The centers of the mandibular foramina, the starting points of the mandibular canal, underwent significant changes in the transverse and sagittal dimensions.

Investigation into effects of cooling rate on properties of polyamide 12 parts in the multi jet fusion process

2020 ◽  
Vol 26 (10) ◽  
pp. 1789-1795
Author(s):  
Mattia Mele ◽  
Giampaolo Campana ◽  
Gregorio Pisaneschi ◽  
Gian Luca Monti
Keyword(s):  
Cooling Rate ◽  
Three Dimensional ◽  
The Body ◽  
Scanning Calorimetry ◽  
Content Type ◽  
Polyamide 12 ◽  
Body Of Knowledge ◽  
Cooling Phase ◽  
The Right ◽  
High Building

Purpose Multi jet fusion is an industrial additive manufacturing technology characterised by high building speed and considerable properties of the parts. The cooling phase represents a crucial step to determine productivity, since it can take up to 4.5 times the building time. The purpose of this paper is to investigate into effects of cooling rate on parts manufactured by multi jet fusion. Crystallinity, density, distortions and mechanical properties of specimens produced through an HP multi jet fusion 4200 are examined. Design/methodology/approach An experimental activity is carried out on specimens cooled down at three different rates. Properties of the parts are analysed by means of differential scanning calorimetry, optical microscopy, three-dimensional scanning and tensile testing. Originality/value The present work makes a contribution to the body of knowledge providing correlations between the cooling phase of multi jet fusion and part properties. These results can be used to choose the right balance between production time and product quality.

Extrapolating and interpolating surfaces in depth

1985 ◽  
Vol 224 (1234) ◽  
pp. 43-56 ◽  
Keyword(s):  
Three Dimensional ◽  
Surface Orientation ◽  
Three Dimensions ◽  
Apparent Depth ◽  
Right Hand ◽  
Pictorial Cues ◽  
Random Dot Stereograms ◽  
Sloping Surface ◽  
The Right ◽  
Hand Image

Random -dot stereograms were generated with a blank area placed in part of the right-hand image so making a patchwork of monocular and binocular areas. The perceived depth and shape of the monocular region, where depth was not explicitly marked, depended in p art on the depth and surface orientation of adjacent binocular areas. Thus a monocular rectangle flanked by two binocular rectangles which were placed in different fronto-parallel planes was seen as a sloping surface spanning the depth between the binocular regions, and, under some conditions, the gradient of a sloping binocular plane extended into a neighbouring monocular area. Division of the monocular region into two by textural discontinuities or discontinuities of motion sometimes altered the shape of the extrapolated surface. Often, though, the shape was unchanged by such discontinuities implying that both two- and three-dimensional features are used to segment a scene into separate surfaces. Pictorial cues also contribute to the shape and apparent depth of the monocular surface. For instance, when subjects viewed a display consisting of portions of a cube of which two ends were shown stereoscopically and one side monocularly, the monocular side was seen in three dimensions filling the gap between the ends. When stereo cues were pitted against pictorial cues, sometimes pictorial cues and sometimes stereo cues dominated, and sometimes the surface contained sharp discontinuities enabling both to be accommodated.

scholarly journals Simulating rhizodeposition patterns around growing and exuding root systems

2021 ◽  
Author(s):  
Magdalena Landl ◽  
Adrian Haupenthal ◽  
Daniel Leitner ◽  
Eva Kroener ◽  
Doris Vetterlein ◽  
...  
Keyword(s):  
Root Architecture ◽  
Three Dimensional ◽  
Temporal Distribution ◽  
Root Systems ◽  
Distribution Patterns ◽  
Three Dimensions ◽  
Root Branching ◽  
Architecture Model ◽  
Spatio Temporal ◽  
Model Approach

1AbstractIn this study, we developed a novel model approach to compute the spatio-temporal distribution patterns of rhizodeposits around growing root systems in three dimensions. This model approach allows us for the first time to study the evolution of rhizodeposition patterns around complex three-dimensional root systems. Root systems were generated using the root architecture model CPlantBox. The concentration of rhizodeposits at a given location in the soil domain was computed analytically. To simulate the spread of rhizodeposits in the soil, we considered rhizodeposit release from the roots, rhizodeposit diffusion into the soil, rhizodeposit sorption to soil particles, and rhizodeposit degradation by microorganisms. To demonstrate the capabilities of our new model approach, we performed simulations for the two example rhizodeposits mucilage and cit-rate and the example root system Vicia faba. The rhizodeposition model was parameterized using values from the literature. Our simulations showed that the rhizosphere soil volume with rhizodeposit concentrations above a defined threshold value (i.e., the rhizodeposit hotspot volume), exhibited a maximum at intermediate root growth rates. Root branching allowed the rhizospheres of individual roots to overlap, resulting in a greater volume of rhizodeposit hotspots. This was particularly important in the case of citrate, where overlap of rhizodeposition zones accounted for more than half of the total rhizodeposit hotspot volumes. Coupling a root architecture model with a rhizodeposition model allowed us to get a better understanding of the influence of root architecture as well as rhizodeposit properties on the evolution of the spatio-temporal distribution patterns of rhizodeposits around growing root systems.

Measurement of Skier-Generated Forces during Roller-Ski Skating

1995 ◽  
Vol 11 (3) ◽  
pp. 245-256 ◽  
Author(s):  
Glenn M. Street ◽  
Edward C. Frederick
Keyword(s):  
Force Measurement ◽  
Three Dimensional ◽  
Axial Loading ◽  
Three Dimensions ◽  
Calibration Data ◽  
Force Transducers ◽  
Sample Data ◽  
Reaction Forces ◽  
The Right ◽  
Force Measurement System

This paper describes a system that was developed to measure ski pole and roller-ski reaction forces in three dimensions during roller-ski skating. Uni-axial force transducers mounted in the right and left ski poles measure axial loading of the poles. Six transducers in one roller-ski measure biaxial loads beneath the foot. A remote computer stores the amplified transducer signals transmitted from the skier through 100 m cables. Three-dimensional video-graphy determines the orientations of the poles and roller-ski in order to resolve the resultant poling and skating forces into three components. Calibration data suggest that the resolution of the force measurement system is ±3 to 9% of the actual poling and skating forces, respectively. Sample data are presented from a VI skating trial during roller-skiing. These data provide the first glimpse at the major functions of the upper and lower body during roller-ski skating and show how the tool could be used to examine the size and effectiveness of skier-generated forces.

scholarly journals Three-dimensional mobility and muscle attachments in the pectoral limb of the Triassic cynodontMassetognathus pascuali

2017 ◽  
Author(s):  
Phil H. Lai ◽  
Andrew A. Biewener ◽  
Stephanie E. Pierce
Keyword(s):  
Body Wall ◽  
Three Dimensional ◽  
Detailed Examination ◽  
The Body ◽  
Three Dimensions ◽  
Glenoid Fossa ◽  
Micro Computed Tomography ◽  
Skeletal Morphology ◽  
Shoulder Muscles ◽  
Maximum Range

ABSTRACTThe musculoskeletal configuration of the mammalian pectoral limb has been heralded as a key anatomical feature leading to the adaptive radiation of mammals, but limb function in the cynodont outgroup remains unresolved. Conflicting reconstructions of abducted and adducted posture are based on mutually-incompatible interpretations of ambiguous osteology. We reconstruct the pectoral limb of the Triassic non-mammalian cynodontMassetognathus pascualiin three dimensions, by combining skeletal morphology from micro-computed tomography with muscle anatomy from an extended extant phylogenetic bracket. Conservative tests of maximum range of motion suggest a degree of girdle mobility, as well as substantial freedom at the shoulder and the elbow joints. The glenoid fossa supports a neutral pose in which the distal end of the humerus points 45° posterolaterally from the body wall, intermediate between classically “sprawling” and “parasagittal” limb postures.Massetognathusis reconstructed as having a near-mammalian complement of shoulder muscles, including an incipient rotator cuff (m. subscapularis, m. infraspinatus, m. supraspinatus, and m. teres minor). Based on close inspection of the morphology of the glenoid fossa, we hypothesize a posture-driven scenario for the evolution of the therian ball-and-socket shoulder joint. The musculoskeletal reconstruction presented here provides the anatomical scaffolding for more detailed examination of locomotor evolution in the precursors to mammals.

Stratified rotating flow over and around isolated three-dimensional topography

1987 ◽  
Vol 322 (1564) ◽  
pp. 213-241 ◽  
Keyword(s):  
Numerical Model ◽  
Three Dimensional ◽  
Wave Pattern ◽  
The Body ◽  
Lee Waves ◽  
Lee Wave ◽  
Long Time ◽  
Dynamical Parameters ◽  
The Right ◽  
Eddy Shedding

Laboratory and numerical experiments have been conducted on the flow of a linearly stratified rotating fluid past isolated obstacles of revolution (conical and cosinesquared profiles). Laboratory experiments are considered for a range of Rossby, Ekman and Burger numbers, the pertinent dynamical parameters of the system. In these experiments, inertial, Coriolis, pressure, viscous and buoyancy forces all play a significant role. Emphasis is given to examining the nature of the time development of the flow fields as well as its long-time behaviour, including eddy shedding. It is shown, for example, that increased stratification tends to diminish the steering effect of the obstacle, other parameters being fixed, at elevation levels above the topography. At levels below the top of the obstacle, increased stratification tends to force the fluid around rather than over the body and this, in turn, tends to develop vortex shedding at smaller Reynolds numbers than would occur in corresponding lower stratification cases. Data for the cone reveal that the Strouhal number for the eddy-shedding regime is relatively insensitive to the values of Ro , Ek and S for the range of parameters investigated. Stratification tends to induce lee waves in the topography wake, and the nature of this lee-wave pattern is modified by the presence of rotation. For example, it is demonstrated that for vertically upward rotation, the lee waves on the right, facing downstream, have a larger amplitude than their counterparts at the same location on the left. The steering effects, as predicted by a three-level quasigeostrophic numerical model, are shown to be in good agreement with the laboratory results for a narrow range of parameter space. The numerical model is used to examine the effects of rotation, friction and stratification in modifying the flow. The quasigeostrophic numerical simulations do not produce eddy shedding, and it is concluded that a full, primitive equation numerical model would be needed to explore this phenomenon.

Stereograms to aid group recognition and trend identification in vegetation data

1978 ◽  
Vol 56 (2) ◽  
pp. 162-165 ◽  
Author(s):  
P. Fewster ◽  
L. Orlóci
Keyword(s):  
Three Dimensional ◽  
Three Dimensions ◽  
Simple Method ◽  
Sample Points ◽  
Left Image ◽  
Dimensional Object ◽  
The Right ◽  
Trend Identification ◽  
Dimensional Picture

When vegetation data are summarized on the basis of some method of ordination, a search for distinct groups or trends is greatly facilitated if the cloud of sample points is viewed under a lens stereoscope in three dimensions. The present paper describes a simple method to construct stereograms and illustrates their application in a classification problem.A stereogram is composed of two images of a three-dimensional object. The left image and the right correspond respectively to sightings with the left eye or the right eye of the observer. The diagrams are placed side by side at a specified distance apart, and when viewed with the aid of a stereoscope, the images will merge resulting in a three-dimensional picture.

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