Rolling Velocity Research Articles

Neutrophils form elongated shear‐derived particles (SDP) via shedding tethers and slings

Neutrophils are innate immune cells greatly contributing to the host defense against bacterial and fungal infection and to various sterile inflammatory conditions. To reach their site of action, circulating neutrophils initially roll, then arrest on the activated vessel wall and then migrate out from the vessel lumen. During rolling at high shear stress, neutrophil microvilli anchored to the endothelium by selectin bonds are pulled out behind the cell into several micron long, thin membrane tubes called tethers. As the anchoring bonds break, the tethers turn into slings and may land in front of the rolling cell and provide adhesive substrate for rolling. Here, we show that both tethers and slings can detach and form elongated neutrophil derived particles, which we call shear‐derived particles (SDP).Cremaster intravital microscopy experiments of Ly6G‐AF647 injected male mice showed the presence of SDPs with or without intrascrotal pretreatment with tumor necrosis factor (TNF), suggesting that in mice the cremaster preparation induced trauma is sufficient to induce SDP formation. In 27 vessels of 8 TNF‐pretreated mice, 234 SDPs were observed with median length of 6.5 μm (range 1.9–112 μm). SDPs appeared when rolling neutrophils left tethers behind, but some were also generated from detached slings. While most SDP appeared arrested, 18% “sneaked” along the vessel wall with the blood flow at a median velocity of 1.13 μm/s (range 0.23–4.95 μm/s), which was significantly lower than the neutrophil rolling velocity of 3.47 μm/s (range 0.7–9.76 μm/s). Free‐floating SDPs were visible in the blood harvested from these mice.SDP production by tether and sling detachment was reproduced in flow chamber experiments using CD16‐AF647 labeled human neutrophils. 11.5 (range 0–42) SDPs per 0.1 μl were found in plasma of 20 healthy donors by a CD16 staining and a standardized confocal microscopy scanning protocol. In 24 septic donors, significantly more (median count 70.5, range 0–140) SDPs were found, which were also longer (median length 5.4 μm vs. 4 μm, range 1.7–23 μm and 1.7–12.8 μm). Image stream (Amnis) analysis confirmed the increase of SDP count in septic plasma and showed that the ratio between CD16+ SDPs and CD16+ vesicles is on the order of 1:1000. We speculate that some SDPs may fragment into spherical vesicles. All significances: p<0.0001 with Student's T‐test.We conclude that rolling or arrested neutrophils lose their tethers and slings. These form a new class of elongated microparticles in the blood, which are elevated in sepsis. Further work is required to better characterize the conditions when SDP form and to characterize the composition and function of these structures.Support or Funding InformationK.Ley: NIH grant HL 78784, A.Marki: AHA postdoctoral fellowship 17POST33410940This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Isolating the influences of fluid dynamics on selectin-mediated particle rolling at venular junctional regions

The objective of this study was to isolate the impact of hydrodynamics on selectin-mediated cell rolling in branched microvessels. Significant advancements have been made in furthering the understanding of complex interactions between biochemical and physical factors in the inflammatory cascade in simplified planar geometries. However, few studies have sought to quantify the effects of branched configurations and to isolate the effects of associated fluid forces. Experimental techniques were developed to perform in vitro adhesion experiments in Y-shaped micro-slides. The micro-slides were coated with P-selectin and microspheres coated with Sialyl-Lewisx were observed as they rolled in the chambers at different wall shear stresses. Study results revealed that microsphere rolling velocities and rolling flux were lowest in regions closest to the apex of a junctional region and were dependent on both branch angle and wall shear stress. The regions closest to the junctional region were shown to have low bulk flow velocities and shear stresses using computational fluid dynamics (CFD) modeling. Collectively, the study demonstrates that despite the presence of a uniform coating of P-selectin, hydrodynamic factors associated with the chamber geometry yield non-uniform effects on particle behavior. These findings could explain why cells have been observed to preferentially adhere or transmigrate near junctional regions. Future characterization of inflammatory processes in microvascular network configurations is therefore crucial for furthering our fundamental understanding of inflammation.

An Experimentally Determined State Diagram for Human CD4+ T Lymphocyte CXCR4-Stimulated Adhesion Under Shear Flow

The leukocyte adhesion cascade is important for the maintenance of homeostasis and the ability of immune cells to access sites of infection and inflammation. Despite much work identifying the molecular components of the cascade, and numerous simulations to predict the relationship between molecule density, identity, and adhesion, these relationships have not been measured experimentally. Using surfaces functionalized with recombinant ICAM-1 and/or E-selectin along with immobilized SDF-1α, we used a flow chamber to measure rates of tethering, rolling and arrest of primary naïve human CD4+ T lymphocytes on different surface densities of ligand. Cells required a minimum level of ligand density to progress beyond tethering. E-selectin and ICAM-1 were found to have a synergistic relationship in promoting cell arrest. Surfaces with both ligands had the highest levels of arrest, while surfaces containing only E-selectin hindered the cell's ability to progress beyond rolling. In contrast, surfaces of ICAM-1 allowed only tethering or arrest. Cells maintained constant rolling velocity and time to stop over large variations in surface density and composition. In addition, surface densities of only O(101) sites/μm2 allowed for rolling while surface densities of O(102) sites/μm2 promoted arrest, approximately equal to previously determined simulated values. We have systematically and experimentally mapped out the state diagram of T-cell adhesion under flow, directly demonstrating the quantitative requirements for each dynamic state of adhesion, and showing how multiple adhesion molecules can act in synergy to secure arrest.

Identification and quantification of human microcirculatory leukocytes using handheld video microscopes at the bedside.

Leukocyte recruitment and adhesion to the endothelium are hallmarks of systemic inflammation that manifest in a wide range of diseases. At present, no method is available to directly measure leukocyte kinetics at the bedside. In this study, we validate a new method to identify and quantify microcirculatory leukocytes observed by handheld vital microscopy (HVM) using space-time diagram (STD) analysis. Video clips ( n = 59) containing one capillary-postcapillary venule unit where leukocytes could be observed emanating from a capillary into a venule in cardiac surgery patients ( n = 20) were included. STD analysis and manual counting were used to quantify the number of leukocytes (total, rolling, and nonrolling). Pearson's correlation and Bland-Altman analysis were used to determine agreement between the STDs and manual counting. For reproducibility, intra- and interobserver coefficients of variation (CVs) were assessed. Leukocyte (rolling and nonrolling) and red blood cell velocities were assessed. The STDs and manual counting procedures for the quantification of rolling leukocytes showed good agreement ( r = 0.8197, P < 0.0001), with a Bland-Altman analysis mean difference of -0.0 (-6.56; 6.56). The overall intraobserver CV for the STD method was 1.5%. The overall interobserver CVs for the STD and the manual method were 5.6% and 9.4%, respectively. The nonrolling velocity was significantly higher than the rolling velocity (812 ± 519 µm/s vs. 201 ± 149 µm/s, P = 0.001). STD results agreed with the manual counting procedure results, had a better reproducibility, and could assess the leukocyte velocity. STD analysis using bedside HVM imaging presented a new methodology for quantifying leukocyte kinetics and functions in the microcirculation. NEW & NOTEWORTHY In this study, we introduce space-time diagram analysis of sublingual microcirculation imaging using handheld vital microscopy to identify and quantify the presence and kinetics of human microcirculatory leukocytes. We validated the methodology by choosing anatomical units consisting of a capillary connected to a venule, which allowed precise identification of leukocytes.

Role of flexural stiffness of leukocyte microvilli in adhesion dynamics

Simulations using the Lattice-Boltzmann lattice-spring method (LLM) combined with adhesive dynamics (AD) find that the flexural stiffness of microvilli and their bending deformation have a significant effect on the rolling velocity and on the adhesive forces.

Errors of car wheels rotation rate measurement using roller follower on test benches

The article deals with rotation rate measurement errors, which depend on the motor vehicle rate, on the roller, test benches. Monitoring of the vehicle performance under operating conditions is performed on roller test benches. Roller test benches are not flawless. They have some drawbacks affecting the accuracy of vehicle performance monitoring. Increase in basic velocity of the vehicle requires increase in accuracy of wheel rotation rate monitoring. It determines the degree of accuracy of mode identification for a wheel of the tested vehicle. To ensure measurement accuracy for rotation velocity of rollers is not an issue. The problem arises when measuring rotation velocity of a car wheel. The higher the rotation velocity of the wheel is, the lower the accuracy of measurement is. At present, wheel rotation frequency monitoring on roller test benches is carried out by following-up systems. Their sensors are rollers following wheel rotation. The rollers of the system are not kinematically linked to supporting rollers of the test bench. The roller follower is forced against the wheels of the tested vehicle by means of a spring-lever mechanism. Experience of the test bench equipment operation has shown that measurement accuracy is satisfactory at small rates of vehicles diagnosed on roller test benches. With a rising diagnostics rate, rotation velocity measurement errors occur in both braking and pulling modes because a roller spins about a tire tread. The paper shows oscillograms of changes in wheel rotation velocity and rotation velocity measurement system’s signals when testing a vehicle on roller test benches at specified rates.

Objective measurement of head movement differences in children with and without autism spectrum disorder

BackgroundDeficits in motor movement in children with autism spectrum disorder (ASD) have typically been characterized qualitatively by human observers. Although clinicians have noted the importance of atypical head positioning (e.g. social peering and repetitive head banging) when diagnosing children with ASD, a quantitative understanding of head movement in ASD is lacking. Here, we conduct a quantitative comparison of head movement dynamics in children with and without ASD using automated, person-independent computer-vision based head tracking (Zface). Because children with ASD often exhibit preferential attention to nonsocial versus social stimuli, we investigated whether children with and without ASD differed in their head movement dynamics depending on stimulus sociality.MethodsThe current study examined differences in head movement dynamics in children with (n = 21) and without ASD (n = 21). Children were video-recorded while watching a 16-min video of social and nonsocial stimuli. Three dimensions of rigid head movement—pitch (head nods), yaw (head turns), and roll (lateral head inclinations)—were tracked using Zface. The root mean square of pitch, yaw, and roll was calculated to index the magnitude of head angular displacement (quantity of head movement) and angular velocity (speed).ResultsCompared with children without ASD, children with ASD exhibited greater yaw displacement, indicating greater head turning, and greater velocity of yaw and roll, indicating faster head turning and inclination. Follow-up analyses indicated that differences in head movement dynamics were specific to the social rather than the nonsocial stimulus condition.ConclusionsHead movement dynamics (displacement and velocity) were greater in children with ASD than in children without ASD, providing a quantitative foundation for previous clinical reports. Head movement differences were evident in lateral (yaw and roll) but not vertical (pitch) movement and were specific to a social rather than nonsocial condition. When presented with social stimuli, children with ASD had higher levels of head movement and moved their heads more quickly than children without ASD. Children with ASD may use head movement to modulate their perception of social scenes.

Ball Burnishing Under High Velocities Using a New Rolling Tool Concept

Ball burnishing is a process used to smooth rough surfaces. For not rotational symmetric parts, the process is typically conducted on milling machines. Since it is an incremental process, it is relatively time consuming. Therefore, a rolling tool is developed, which superposes the rotation of the milling spindle with the feed of the machine to increase the rolling velocity. In order to achieve constant rolling forces, hydrostatic ball-burnishing tools are used. Within this work, the influence of this tool concept on the processing time as well as on the leveling of surface irregularities is investigated. This is achieved by a comparison with a conventional ball-burnishing process. Finally, the rotating tool is used to investigate the influence of high rolling speeds on the leveling of the surface. All experiments were carried out with thermally coated specimens. A model for calculating the strain rates at the roughness peaks during ball burnishing is derived. For the experiments carried out with the rotating rolling tool, rolling velocities of 50,000 mm/min were realized. Calculations with the developed model showed that this results in local strain rates at the roughness peaks of up to 1384 s−1. In addition, the flow stresses at the roughness peaks were calculated. Compared with quasi-static experiments, the flow stress drops to less than the half under high velocities. This results in a better leveling of the surface for rolling velocities between 10,000 mm/min and 25,000 mm/min. A further rise of the rolling speed increases the flow stress again and thereby reduces the possible leveling.

Numerical modelling of the temperature distribution in the cross-section of an earthmover tyre

• Finite element model of a 23.5R25 earthmover tyre. • Method used to numerically compute the temperature distribution in the tyre’s cross-section. • Evaluation of the maximum tyre temperature for different load case and inflation pressure conditions. • Verification of the simulated tyre deformation is based on experimental results received from the tyre manufacturer. The numerical modelling of the internal heat generation in passenger vehicle tyres using finite element analysis is a well-known numerical approach. However, this application is rather uncommon for earthmover tyres. This paper describes the development of a finite element model of a 23.5R25 earthmover tyre for the numerical modelling of the temperature distribution in the tyre cross-section at steady-state heat transfer conditions using an uncoupled analysis procedure. Considering the non-linear behaviour of the rubber compounds used for the manufacturing of these tyres, as well as the complexity associated with the composite structural aspects of the tyre, the material properties used for the proposed numerical model were established experimentally. In the analyses completed, the tyre behaviour was studied by simulations at various inflation pressures, loads and rolling velocities. The numerical tyre defection was within an 8% deviation from the actual tyre behaviour. Thermal simulation results were used to derive an equation that can be used to predict the maximum temperature that would occur in the tyre’s cross-section as a function of its vertical deflection, its forward rolling velocity and the ambient temperature of the surroundings. The numerical models and simulations presented in this paper were completed using MSC.Marc/Mentat.

Rolling viscous drops on a non-wettable surface containing both micro- and macro-scale roughness

It has previously been shown that when a liquid drop of high viscosity is placed on a non-wettable inclined surface, it rolls down at a constant descent velocity determined by the balance between viscous dissipation and the reduction rate of its gravitational potential energy. Since increasing the roughness of the surface boosts its non-wetting property, the drop should move faster on a surface structured with macrotextures (ribbed surface). Such a surface was obtained from a superhydrophobic soot coating on a solid specimen printed with an extruder-type 3D printer. The sample became superoleophobic after a functionalization process. The descent velocity of glycerol drops of different radii was then measured on the prepared surface for varied tilting angles. Our data show that the drops roll down on the ribbed surface approximately 27% faster (along the ridges) than on the macroscopically smooth counterpart. This faster velocity demonstrates that ribbed surfaces can be promising candidates for drag-reduction and self-cleaning applications. Moreover, we came up with a modified scaling model to predict the descent velocity of viscous rolling drops more accurately than what has previously been reported in the literature.

Establishment of Processing Maps for 25vol.% B&lt;sub&gt;4&lt;/sub&gt;C&lt;sub&gt;P&lt;/sub&gt;/AA6061 Composite and its Application in Hot Pack-Rolling Process

The hot workability and hot pack-rolling process of B4CP/AA6061 composite were studied. The results showed that the addition of B4C particles could effectively promote the dynamic recrystallization (DRX) process of the composite. DRX and DRX grains growth were dominant deformation mechanism during hot deformation of B4CP/AA6061composite. Typical instability defects included micro voids and particle aggregation. The optimum processing parameters for good workability were obtained in the temperature range of 450°C-500°C and strain rate range of 0.01s-1-0.1s-1. According to the flow stress curves and processing maps, a temperature of 500°C and a rolling velocity of 40 mm/s were chosen for pack-rolling experiments. The pack-rolled composite sheets in the RD and TD showed more homogeneous DRX grains than as-HIPed microstructures, which might indicate that hot pack-rolling could lead to more homogeneous microstructures without any edge cracking and surface cracking.

Analysis of deformation characteristics and microstructure variation of thick plate during asymmetric shear rolling

Aluminium alloy thick plate is widely used in field of aerospace and automobile industry for its light weight, high strength, good corrosion resistance and formability. Hot rolling is the key process of preparation for thick plates, however, the conventional symmetrical rolling process causes large deformation on the surface and small deformation in the central portion of the thick plate, resulting in inhomogeneous deformation, microstructure and property distributions through the thickness direction of the plate. Asynchronous rolling is beneficial for deformation permeation into the central part of thick plate with introduction of strong shear strain due to velocity asymmetry of two work rolls. However, the plate will bend towards the slower roll due to deformation asymmetry at upper and lower surface of the plate and serious bending is bad for multi-pass rolling process. Asymmetrical shear rolling with velocity asymmetry and geometry asymmetry is adopted in this study. Compared to asynchronous rolling, there is a horizontal offset distance of upper roll in outlet direction. A moment will be applied to the plate in the opposite direction of bending towards the slower roll by an offset distance of the slower roll. The comparisons of distributions of equivalent strain, temperature, DRX fraction and average grain size between symmetrical rolling and asymmetrical shear rolling are studied. The effects of velocity asymmetry and offset distance on microstructure variation and microstructure distribution at different positions of the plate are studied. Due to larger velocity of lower work roll, larger equivalent strain and higher temperature appear at lower layer of the plate, which results in higher DRX fraction and finer grain size. The speed ratio contributes greatly to sufficient DRX process and finer grain size; while the ascending offset distance decreases the DRX fraction. Therefore, speed ratio plays significant role in deformation permeation and grain refinement in asymmetrical shear rolling and the offset distance is mainly used to decrease the bending behaviour of the plate. This study can provide guidance to thick plate preparation with good properties in asymmetrical rolling process.

Software in the loop framework for the performance assessment of a navigation and control system of an unmanned aerial vehicle

The use of autonomous vehicles is currently a growing trend, particularly in applications such as manufacturing, hazardous material handling, and surveillance [1]. A quadcopter is an emerging rotorcraft concept for an unmanned aerial vehicle (UAV) that is equipped with four rotors, two pairs of counter-rotating, and fixedpitch blades located at the four corners of the vehicle [2]. In a quadcopter system, yaw is controlled by increasing the angular velocity of rotors that spin in the same direction to a level higher than the velocity of other rotor pairs, and pitch or roll is controlled by increasing the angular velocity of a rotor to a level greater than the velocity of a diametrically opposite rotor (Figure 1) [3].

Coordinated Standoff Target Tracking Guidance Method for UAVs

We need a coordinated control method to continuously track a moving target using a group of UAVs. In this paper, we study the predicted reference point guidance method, where the target is considered to move with a constant velocity in a very short time window and the trajectories of the UAVs are designed as several tiny arcs around the target. The control law of the UAV is divided into roll angle control and velocity control. Simulations are used to verify that the proposed control laws have smaller standoff distances and phase angle control errors than the Lyapunov vector field guidance and model-based predictive control, and the wind is considered in the simulation, too. Therefore, we show that our proposed method has higher steady state accuracy among existing techniques.

Dynamics of non-holonomic systems with stochastic transport.

This paper formulates a variational approach for treating observational uncertainty and/or computational model errors as stochastic transport in dynamical systems governed by action principles under non-holonomic constraints. For this purpose, we derive, analyse and numerically study the example of an unbalanced spherical ball rolling under gravity along a stochastic path. Our approach uses the Hamilton-Pontryagin variational principle, constrained by a stochastic rolling condition, which we show is equivalent to the corresponding stochastic Lagrange-d'Alembert principle. In the example of the rolling ball, the stochasticity represents uncertainty in the observation and/or error in the computational simulation of the angular velocity of rolling. The influence of the stochasticity on the deterministically conserved quantities is investigated both analytically and numerically. Our approach applies to a wide variety of stochastic, non-holonomically constrained systems, because it preserves the mathematical properties inherited from the variational principle.

Experimental study of in-line heat treatment of 1.0577 structural steel

In-line heat treatment is frequently used in rolling mills because it offers a significant improvement of rolled product mechanical properties with costs benefits. This method allows achieving required mechanical properties without necessity of additional alloying and rolled product reheating. Disadvantage of in-line heat treatment is fixed rolling velocity which is typically strong parameter in controlling of final cooling regime. Water flow rate, pressure, type, size and position of nozzles, water temperature are examples of parameters influencing cooling intensity and the Leidenfrost temperature. Laboratory experimental study is needed to design well controllable cooling system which allows keeping required cooling regimes for various product steel grades and dimensions. This paper describes experimental stages of cooling system designing procedure for improving structural steel 1.0577 mechanical properties. First experimental part began with building of cooling intensities (heat transfer coefficients - HTC) database for tested several nozzles configurations. Then required cooling regime was selected according to the continuous cooling transformation diagram. The target was obtaining harder (quenched) material with good ratio between elongation and strength. The final equalization temperature was set to 600 °C in the whole body. Numerical simulations of cooling followed based on the knowledge of heat transfer coefficients from database. Appropriate nozzle configuration was chosen and numerical results were experimentally validated using modified Jomminy test. A hardness was improved significantly up to thickness of 12 mm (275 HV under sprayed surface decreasing to 180 HV in 12 mm). When the required material structure and hardness verified appropriateness of cooling regime by previous tests, the first design of cooling section was done. Full scale sample was heat treated on a new experimental stand (Karusel) which was developed by HeatLab. It enabled to simulate real cooling process in laboratory conditions. The sample was heated to rolling temperature and moved through the intensive spray (surface temperature drop to 300 °C) and then through the soft spray because of water savings. The cooling stopped in required time and the sample tempered to the target equalization temperature of 600 °C in the whole body. Finally, the hardness was measured, tensile and Charpy pendulum tests were done to confirm design of cooling unit. The hardness of the original material was constant along depth – 160 HV. It was improved by heat treatment – decreasing from the sprayed surface (265 HV) to the depth of 12 mm (175 HV). The minimal yield strength of the heat treated material increased from 355 MPa 400 MPa (maximal up to 750 MPa – closed to the sprayed surface). The sample was cooled to -20 °C for Charpy pendulum test. The pendulum energy of heat treated material rapidly increased from 50 J to 150 J.

Downregulation of miR-31 in Diabetic Nephropathy and its Relationship with Inflammation

Background/Aims: There is a lack of reliable biological markers for the early diagnosis of diabetic nephropathy (DN) during type 2 diabetes. In this pilot study we aim to assess whether miR-31 levels are modulated by the presence of DN and whether the expression of this miRNA is related to leukocyte-endothelial interactions and inflammation. Methods: Thirty-one T2D patients were enrolled in this pilot study; 18 with no diabetic complications and 13 with diabetic nephropathy. 24 non-diabetic subjects and 13 T2D patients with retinopathy (absent of other complications) were included to test the specificity of miR-31. Following anthropometric and biochemical evaluation, serum miR-31 levels were assessed by Real Time-PCR. Leukocyte-endothelial interactions were evaluated by a parallel flow chamber in vitro model. Serum TNFα, IL-6 and ICAM-1 levels were determined by XMAP-technology in a flow cytometry-based Luminex 200 instrument. Results: Serum miR-31 levels were similar between control and T2D subjects. However, T2D patients with DN displayed reduced levels of miR-31 with respect to patients without complications. This decrease in miR-31 was more pronounced in patients with macroalbuminuria than in those with microalbuminuria and was specific for DN, since patients with retinopathy displayed unaltered miR-31 levels. The presence of DN involved a lower leukocyte rolling velocity and an increased rolling flux and adhesion. miR-31 levels were positively correlated with leukocyte rolling velocity and negatively associated to leukocyte adhesion, TNFα, IL-6 and ICAM-1 levels. Conclusion: Serum miR-31 may be a biomarker for DN in T2D patients. The regulation of this miRNA seems to be related to the recruitment of leukocytes to vascular walls induced by pro-inflammatory and adhesion molecules.

Study on dependency of rolling velocity and vibration acceleration in a rolling roller on fine coals upon the running velocity

Study on dependency of rolling velocity and vibration acceleration in a rolling roller on fine coals upon the running velocity

Rolling neutrophils form tethers and slings under physiologic conditions in vivo.

Human and mouse neutrophils are known to form tethers when rolling on selectins in vitro. Tethers are ∼0.2 μm thin, ∼5-10 μm-long structures behind rolling cells that can swing around to form slings that serve as self-adhesive substrates. Here, we developed a mouse intravital imaging method, where the neutrophil surface is labeled by injecting fluorescently labeled mAb to Ly-6G. Venules in the cremaster muscle of live mice were imaged at a high frame rate using a confocal microscope equipped with a fast resonant scanner. We observed 270 tethers (median length 3.5 μm) and 31 slings (median length 6.9 µm) on 186 neutrophils of 15 mice. Out of 199 tether break events, 123 were followed by immediate acceleration of the rolling cell, which shows that tethers are load-bearing structures in vivo. In venules with a high wall shear stress (WSS; > 12 dyn/cm2 ), median rolling velocity was higher (19 μm/s), and 43% of rolling neutrophils had visible tethers. In venules with WSS < 12 dyn/cm2 , only 26% of rolling neutrophils had visible tethers. We conclude that neutrophil tethers are commonly present and stabilize rolling in vivo.

A potential hot stamping process for microstructure optimization of 22MnB5 steels characterized by asymmetric pre-rolling and one- or two-step pre-heating

In this paper, a study on the innovative hot stamping process and the typical microstructures is presented, aiming to clarify insights into the influence of processing variables (asymmetric rolling temperature, rolling reduction, pre-heating method, and so on) on the evolution of microstructure, in order to evaluate the feasibility of the new process to improve properties of 22MnB5 steels. TEM investigations of asymmetrically rolled samples indicate different morphologies of dislocation density and pearlite with altering the rolling reduction, velocity ratio (VR) and rolling temperature. And the study demonstrates that asymmetric rolling before hot stamping process greatly promotes the austenite transformation during the pre-heating stage, especially when the rolling temperature is lowered to liquid nitrogen temperature (LNT) and the velocity ratio is higher than 1.5. And two-step pre-heating with induction heater and roller hearth furnace contributes positively to the austenite grain refinement in pre-deformed 22MnB5 steel. Another relevant conclusion is that the cooling microstructures can also be adjusted by changing the pre-deformed temperature of the samples.