Cycle Speed Research Articles

Uncovering cell cycle speed modulations with statistical inference.

Uncovering cell cycle speed modulations with statistical inference.

Statistical inference with a manifold-constrained RNA velocity model uncovers cell cycle speed modulations.

Across biological systems, cells undergo coordinated changes in gene expression, resulting in transcriptome dynamics that unfold within a low-dimensional manifold. While low-dimensional dynamics can be extracted using RNA velocity, these algorithms can be fragile and rely on heuristics lacking statistical control. Moreover, the estimated vector field is not dynamically consistent with the traversed gene expression manifold. To address these challenges, we introduce a Bayesian model of RNA velocity that couples velocity field and manifold estimation in a reformulated, unified framework, identifying the parameters of an explicit dynamical system. Focusing on the cell cycle, we implement VeloCycle to study gene regulation dynamics on one-dimensional periodic manifolds and validate its ability to infer cell cycle periods using live imaging. We also apply VeloCycle to reveal speed differences in regionally defined progenitors and Perturb-seq gene knockdowns. Overall, VeloCycle expands the single-cell RNA sequencing analysis toolkit with a modular and statistically consistent RNA velocity inference framework.

FEATURES OF FUNCTIONAL DIAGNOSTICS OF OPTIC NERVE DAMAGE IN CASE OF HEAD INJURY

Introduction. Traumatic optic nerve damage is a rare complication of a head injury. Symptoms of primary damage appear at the time of first diagnostic in the early period and mask TON’s signs. Understanding of visual disturbances for the patient comes in a later period, when recovery is limited due to the irreversibility of the received injuries. Difficulties of early diagnosis of optic nerve damage in case of head trauma encourage the search for new, more informative methods. The aim of the study was to analyze the functional manifestations of the optic nerve damage in case of head injuries with different localization. Materials and methods. 366 cases (732 eyes) of patients with traumatic optic neuropathy (TON) were studied according to archival data in the period from 2014 to 2019. The control group consisted of 58 practically healthy persons (116 eyes). All patients were divided into three groups: A group - patients with traumatic brain injury (TBI) was 120 persons, B group - patients with craniofacial injury (CFI) - 118 persons and C group - with combined injuries - 128 injured. The degree of optic nerve damage was assessed using visometry, pupillometry, and perimetry. Results. In case of craniocerebral injury, decrease of visual acuity with an average value of 0.92±0.06 corresponded to degrees 0 (93%) and I (7%). In the case of craniofacial trauma, according to the research, visual acuity decreased to 0.76±0.13 (by 0.24, 24% compared to the control group, p<0.05). The first degree (23%) and the second degree (7%) were determined. With a combined primary head injury, visual acuity decreased to 0.42±0.21 (by 0.58, 58%, compared to the control group, p<0.05). One third were patients with I, II and III degrees of visual impairment. The use of static perimetry made it possible to detect damage to the optic nerve in patients with 0 degrees of reduced visual acuity. At the same time, 88% of patients of A group (n=120) had 0A class, 23% of B group (n=118) had 0B class, and in C group (n=122) there was almost no. The relative afferent pupillary defect’s test was negative at 0A group of vision loss, but the pupil cycle speed (PSC) was reduced in all patients. This confirms damage to the optic nerve in patients with high visual acuity This study showed that patients with TBI had high visual acuity in 93% of cases, The visual acuity was around 0.5-1.0, but sensitivity in the central part of the visual field decreased by 12 times, and the pupil reaction rate decreased by 55% compared to the control group. In case of craniofacial trauma (B group), visual acuity decreased to 0.76±0.13 (by 0.24, 24% compared to the control group, p<0.05). I degree (23%) and II degree (7%) decrease of visual acuity was determined. As for the sensitivity in the central part of the visual field, it was 46.59% lower than in the A group. In patients with a combined injury of the head and face, a third of the injured had visual acuity less than 0.1, which is not found in other variants of injury. Conclusions. Analysis showed that severity of optic nerve damage depends on localization of the head injury. The use of static perimetry and pupillometry is important for the early diagnosis of TON in conditions with high visual acuity when other symptoms are weak or not amenable to examination.

Experimental study on the cerium oxide nanoparticles doped in diesel fuel improving the cold start performance of diesel engines at high-altitude and low-temperature environments

CeO2 nanoparticles are effective fuel additives that enhance fuel spray, atomization, and combustion characteristics due to their high catalytic activity and excellent thermal properties. When added to fuel, CeO2 nanoparticles significantly improve in-cylinder combustion, and engine performance, and reduce pollutant emissions under normal engine operating conditions. Diesel engines encounter persistent challenges during cold starts at low temperatures and high altitudes. However, there is limited research on the effects of CeO2 nanoparticles on ignition and combustion at low temperatures and cold start performance. This study aims to evaluate the impact of CeO2 nanoparticles doping in diesel fuel on the cold start performance of diesel engines in high-altitude and low-temperature environments. Diesel fuel doped with CeO2 nanoparticles at various concentrations was prepared using magnetic stirring and ultrasonication. The cold start performance of the test engine was assessed in an environmental chamber. This work investigated and evaluated the improvements of CeO2 nanoparticles on cold start performance from three perspectives: general low-temperature conditions, high-altitude environments, and extreme low-temperature scenarios with diethyl ether premixing. Experimental results indicate that incorporating CeO2 nanoparticles expanded the critical temperature required for a successful cold start from 0 °C to −5 °C. At high altitudes, the addition of CeO2 nanoparticles effectively increased the proportion of efficient combustion, evidenced by single peak and parent peak patterns during cold starts. CeO2 nanoparticles facilitated the transition from low-temperature to high-temperature reactions, promoting fuel ignition during the first injection cycle and reducing speed fluctuations during cold starts with diethyl ether premixing at −40 °C. Furthermore, adding CeO2 nanoparticles prevented detonation and rapid pressure surges during cold starts. Overall, doping diesel fuel with CeO2 nanoparticles proves to be an effective method for enhancing cold start performance in diesel engines. This study offers a novel approach for improving diesel engine cold start performance in high-altitude and low-temperature conditions.

Determining the differences in O3-NOx-VOCs sensitivity between sauna and roast days

Temperature is a key meteorological factor that affects tropospheric ozone (O3), with both humid-heat (sauna days) and dry-heat (roast days) conditions leading to O3 exceedances. However, the mechanisms influencing O3 formation and degradation under these two weather conditions remain unclear. Therefore, experiments were conducted in Beijing from 2019-2021 to observe O3, its precursors, and related meteorological elements. A total of 18 days with O3 exceedances were selected, including 10 sauna days and 8 roast days. The results of this study revealed that on roast days, the sensible heat flux was 143.5 W/m2 greater and the wind speed gradient was 0.018 s-1 greater than those on sauna days, indicating more intense thermal and dynamic turbulence. The strong turbulence enhanced the vertical cycle of nitrogen dioxide (NO2) and O3, resulting in a 58.2 μg/(m2·h) increase in NO2 upward transport rate and a 1,034.4 μg/(m2·h) increase in O3 downward transport rate on roast days than sauna days. Subsequently, a box model analysis was used to examine O3 formation under the two types of weather conditions, revealing that the NO2-O3 vertical cycling speed dominated the O3 sensitivity. The O3 sensitivity was synergistically controlled by nitrogen oxides (NOx) and volatile organic compounds on sauna days, while it tended to be NOx-limited on roast days. The aim of this study was to provide a scientific theoretical basis for the control of O3 under different types of high temperature weather conditions.

Design of Solar Electric Bicycle Based on Pulse Width Modulation on Throttle as DC Motor Speed Regulator

Electric bicycles are designed to use renewable energy to support the government's efforts to reduce carbon emission consumption. Problems in every region or city regarding fueled vehicles certainly increase air pollution. Generally, electric bicycles are designed to be a solution and are used in daily life to carry out daily activities by requiring a bicycle gas throttle control that can assist the driver or person in controlling the speed of the electric bicycle. In this study, designing a solar electric bicycle as environmentally friendly energy based on PWM signals to determine the duty cycle value or duty cycle with an optimized PWM value can affect the speed system (km / h) in Revolutions Per Minute (RPM) to determine the performance of the DC motor. The electric bicycle uses 30Wp solar power, two 12V 7.5 Ah batteries assembled in series, and a 24V 250W DC brushless motor. Based on the design results with a total weight of 37kg electric bicycle plus the weight of 55kg, 65kg, 75kg, and 85kg driver variations, the total controller power value is 163.44 watts. The results of duty cycle testing (duty cycle) were 25%, 50%, 75%, and 98%, with 249.9 as the maximum value of PWM and 9.8 Vout generated against the maximum speed of the electric bicycle of 2648 RPM or the equivalent of an electric bicycle speed of 18-28 km/hour. In this case, the electric bicycle is in a condition suitable for use to carry out daily activities by utilizing clean, cheap and appropriate energy

The biological and preformed carbon pumps in perpetually slower and warmer oceans

Abstract. The marine carbon cycle is vitally important for climate and the fertility of the oceans. However, predictions of future biogeochemistry are challenging because a myriad of processes need parameterization and the future evolution of the physical ocean state is uncertain. Here, we embed a data-constrained model of the carbon cycle in slower and warmer ocean states as simulated under the RCP4.5 and RCP8.5 (RCP: Representative Concentration Pathway) scenarios for the 2090s and frozen in time for perpetuity. Focusing on steady-state changes from preindustrial conditions allows us to capture the response of the system integrated over all the timescales of the steady-state biogeochemistry, as opposed to typical transient simulations that capture only sub-centennial timescales. We find that biological production experiences only modest declines (of 8 %–12 %) because the reduced nutrient supply due to a more sluggish circulation and strongly shoaled mixed layers is counteracted by warming-stimulated growth. Organic-matter export declines by 15 %–25 % due to reductions in both biological production and export ratios, the latter being driven by warming-accelerated shallow respiration and reduced subduction of dissolved organic matter. The perpetual-2090s biological pump cycles a 30 %–70 % larger regenerated inventory accumulated over longer sequestration times, while preformed DIC is shunted away from biological utilization to outgassing. The regenerated and preformed DIC inventories both increase by a similar magnitude. We develop a conceptually new partitioning of preformed DIC to quantify the ocean's preformed carbon pump and its changes. Near-surface paths of preformed DIC are more important in the slower circulations, as weakened ventilation isolates the deep ocean. Thus, while regenerated DIC cycling becomes slower, preformed DIC cycling speeds up.

Electrochemical treatment of azo dye wastewater by dynamic flow diaphragm system: Response surface methodology optimization and energy consumption analysis

In this experiment, the degradation process of azo dye wastewater was studied based on the diaphragm double chamber electrochemical reactor, taking the mono azo dye amaranth as an example. Through the circulation flow of appropriate volume of wastewater in the cathode and anode chamber, the simultaneous action of cathode and anode was realized, and the degradation and decolorization efficiency of azo wastewater was improved while reducing energy waste. The optimal reaction conditions optimized by response surface methodology were as follows: the voltage was 20.74 V, the plate spacing was 4.89 cm, and the cycle speed was 60.66 rad / min. The optimal decolorization rate was 99.66 %. The energy consumption analysis of the dynamic flow diaphragm system electrochemical method and the static flow diaphragm system electrochemical method for the treatment of azo dye wastewater was compared and analyzed. In addition, the possible degradation process of azo dye wastewater by dynamic flow electrochemistry was inferred by ultraviolet spectroscopy and mechanism prediction analysis. The experimental results show the great potential of the dynamic flow membrane system process in the treatment of azo dyes.

Scenario-oriented adaptive ECMS using speed prediction for fuel cell vehicles in real-world driving

To exploit the energy-saving potential and optimize the battery state of charge (SOC) maintaining capability of energy management strategies for fuel cell hybrid vehicles in specific driving scenarios, this study proposes a scenario-oriented adaptive equivalent consumption minimization strategy (SA-ECMS) based on a Nanjing-oriented driving cycle (NODC) and future speeds predicted via a hybrid neural network model. The proposed strategy determines the initial value of the equivalent factor (EF) and the proportional coefficient of the adaptive increment based on the NODC. Then, it periodically adjusts the EF via local optimization process according to the predicted speed to enhance scenario-specific adaptability and energy efficiency performance. Simulation results show that the hybrid neural network model achieves an average calculation time of 0.0033 s with a root-mean-square error of 0.85 m/s for 10 s prediction horizon, outperforming existing speed prediction models. Compared with the existing SOC feedback-based ECMS, the proposed SA-ECMS effectively suppresses the battery SOC within a narrower fluctuation range of −0.12% to 0.33%, achieves a deviation of only 0.0026 from the SOC reference value, and reduces the equivalent hydrogen-fuel consumption by 2.49% to 7.06 g/km.

A non-stationary bivariate extreme value model to estimate real-time pedestrian crash risk by severity at signalized intersections using artificial intelligence-based video analytics

Vehicle-pedestrian crashes are generally severe due to the vulnerability of pedestrians compared to the occupants of vehicles. However, the estimation of pedestrian crash risk by severity has not been given adequate attention in the field of proactive safety assessments applying traffic conflict techniques. This study proposes a novel analytical framework to estimate real-time pedestrian crash risk by severity at the signal cycle level while incorporating the effect of time-varying exogenous variables. Specifically, the study applies a non-stationary bivariate extreme value model to jointly model the post encroachment time and Delta-V for estimating real-time pedestrian crash risk by severity at individual signal cycles. The proposed framework is tested on 144 h of video data collected from three signalized intersections in Queensland, Australia. The developed bivariate extreme value model has been found to reliably predict severe and non-severe pedestrian crash frequencies compared to the historical crash records of severe and non-severe pedestrian crashes at those signalized intersections. Results suggest that the frequency of pedestrian conflicts per signal cycle and average pedestrian speed in a signal cycle are associated with real-time pedestrian crash risks. In addition, pedestrian conflicts per signal cycle and average vehicle speed per cycle were associated with the interaction severity component of the non-stationary bivariate extreme value model. The proposed proactive estimation of pedestrian crash risk by severity levels can help design time-sensitive countermeasures for vulnerable road users.

The Effect of Arm Movements on the Dynamics of the Wheelchair Frame during Manual Wheelchair Actuation and Propulsion

Wheelchair propulsion and actuation are influenced by the moving masses of the wheelchair user; however, the extent of this effect is still unclear. The main evidence of this effect is that the speed of the wheelchair frame continues to increase after the end of the push phase. The wheelchair’s speed was measured using IMUs and the duration of the push period was recorded using miniaturised pressure sensors attached to the driver’s middle fingers. The velocity and acceleration were determined for various average stroke cycle speeds to determine the speed dependency of the acceleration. The wheelchair was then mounted on a force plate to measure the inertial forces of the hands moving back and forth. The aerodynamic drag and rolling resistance forces were determined from coast-down experiments. Based on the measured forces, the behaviour of the force and velocity profiles was finally modelled by gradually reducing the mass of the arms and thus their inertial force. The results showed that the wheelchair is accelerated throughout the push phase (except for a temporary deceleration in the middle of the push phase at higher velocities), and that this acceleration continues well after the push phase. In the second half of the recovery phase, the wheelchair decelerates. The horizontal inertial forces measured on the force plate are predominantly negative in the push phase and in the second half of the recovery phase, and positive in the first half of the push phase, and their impulse is zero due to the conservation of momentum. Modelling the wheelchair with moving masses showed that reducing the horizontal inertial forces has no effect on the driver’s propulsive force but reduces the velocity fluctuations. The main conclusion of this research is that the wheelchair user’s power should be calculated only from the pure propulsive force that is required in the push phase to overcome the dissipative forces and that enables the gain or loss in speed per stroke cycle, but not directly from the measured velocity.

Harnessing cardiac power: Heart kinetic motion analysis for energy harvesters

Accurately estimating the complex motion of the heart can unlock enormous potential for kinetic energy harvesting. This paper presents a foundational dataset for heart kinetic motion through in-vivo tests and investigates the most influential factors in heart kinetic motion. In-vivo tests on a living pig's heart, with signal processing, were carried out to study the heart movement by heart beating and respiration motions. A network of nine points on the heart was employed for in vivo measurements. These measurements illustrated the kinetic energy signals in displacement, velocity, and acceleration. The results indicated that the motion level varies in distinct locations over epicardium. The statistical features and autocorrelations were reported for these points, illustrating the highest displacement and acceleration. Each heartbeat generated an energy of 14.35 mJ and a power of 1.03 W. However, this available energy is not uniformly distributed. The results illustrated that not only is cardiac movement location-dependent, but the speed of cardiac displacement cycles is also location-dependent. The right atrium has the highest cardiac kinetic movement with an amplitude of 16.19 mm displacement and 16.3 m/s2 acceleration. To evaluate the energy harvesting possibility from the heart's motion, a piezoelectric energy harvester was simulated by the finite element method, implying that the energy harvesting level significantly depends on implant location over epicardium. The results of this study open the potential of designing novel energy harvesters based on accurate heart movements and provide a foundation for future investigations of energy harvesting for leadless pacemaker energy systems.

Affordance-based control of braking in cycling: Experience reveals differences in the style of control

We investigated whether in an in-situ collision avoidance experiment cyclists regulate braking by adopting an affordance-based control strategy. Within an affordance-based control strategy for braking, deceleration is controlled relative to the maximum achievable deceleration rather than by nulling out deviations from ideal deceleration, and potentially allowing for different braking styles. Twenty active- and eighteen inactive-cyclists were asked to cycle on a straight path in an indoor gym and to stop as close as possible in front of a stationary obstacle. Maximum achievable deceleration was manipulated by loading the bike: no-load, load-5 kg, and load-10 kg. Two approach distances were used to vary cycling speed. Participants in both groups stopped farther from the obstacle when approaching with long- than short-initial distance conditions. No systematic effects of loading on braking performance and control were found across the two groups. However, both groups did increase the magnitude of brake adjustments as ideal deceleration increased and got closer to the action boundary, even when current deceleration approached the ideal deceleration. This indicates that participants adopted an affordance-based control strategy for braking. Two braking styles were identified: an aggressive style, characterized by a late braking onset and a high, steep peak in ideal deceleration, and a conservative style, characterized by an early braking onset and gradual, linear increase in ideal deceleration. The aggressive braking style was more prevalent among the active-cyclists. We suggest that the braking styles emerge from differences in calibration between information and action. The novelty of our work lies in confirming that cyclists adopt an affordance-based control strategy in an in-situ experiment and in demonstrating and explicating how affordance-based control can incorporate the emergence of different styles of braking.

Statistical modeling and optimization of clad geometry in laser cladding of Amdry 961 on Inconel 713LC superalloy with response surface methodology

In this study, Inconel 713LC superalloy was laser-clad with Amdry 961 powder using a 1 kW fiber laser. Response surface methodology was used to investigate the effect of laser power, duty cycle, and scanning speed on the deposited bead's geometry (width, height, and clad angle) and the dilution ratio. Interestingly, higher laser power and duty cycle increased bead width, clad angle, and dilution ratio but decreased bead height, while the opposite effect was observed for scanning speed. The process optimization was performed by a simultaneous optimization technique. This technique identified the ideal parameters: a laser power of 840 W, a duty cycle of 79.5%, and a scanning speed of 4.38 mm/s. These settings effectively optimized clad properties, with mean absolute errors of 7.96% for clad width, 14.74% for clad height, 16.71% for clad angle, and 5.166% for dilution ratio. These values demonstrate the precision of optimized parameter settings.

Experimental investigation and optimization of modification during coaxial waterjet-assisted femtosecond laser drilling

Waterjet-assisted laser drilling technology facilitates the fabrication of high-quality micro-holes by utilizing the collaborative benefits of waterjets and lasers. In this study, the coaxial waterjet-assisted laser drilling (CWALD) technique was employed to improve the properties of micro-holes during femtosecond laser drilling. Based on computational fluid dynamics (CFD) simulations, the stability of the waterjet was initially verified by optimizing the structure of the watercourse and nozzle shape in the CWALD device. Furthermore, a comparative experiment between laser direct drilling (LDD) and CWALD revealed that while CWALD can produce well-rounded micro-holes with a high aspect ratio, it exhibits lower efficiency and results in a larger heat-affected zone (HAZ). To address these drawbacks associated with CWALD, a two-step coaxial waterjet-assisted composite laser drilling (TS-CWALD) method was proposed. TS-CWALD involves applying CWALD for secondary modification of micro-hole shape following LDD with punching. This modification process is pivotal for enhancing drilling accuracy but requires consideration of multiple parameters. For this purpose, regression models were established for the inlet diameter, outlet diameter, and taper; response surface methodology was then employed to optimize these parameters. Subsequently, interactive effects analysis was conducted on different responses based on laser pulse energy, frequency, modification speed, and number of modification cycles. The adequacy of the developed models was subsequently verified using analysis of variance methods. Finally, the successful fabrication of a film hole with an inlet diameter of 205 μm and an outlet diameter of 200 μm, featuring a taper of only 0.2°, was achieved ultimately through meticulous parameter optimization. Furthermore, the micro-hole retained a minimal HAZ. The optimized parameters encompassed a pulse energy of 20.6 μJ, frequency of 127 kHz, modification speed of 3 mm/s, and shape modification carried out over 335 cycles.

Cycling speed variation: a multilevel model of characteristics of cyclists, trips and route tracking points

AbstractSmooth cycling can improve the competitiveness of bicycles. Understanding cycling speed variation during a trip reveals the infrastructure or situations which promote or prevent smooth cycling. However, research on this topic is still limited. This study analyses speed variation based on data collected in the Netherlands, using GPS-based devices, continuously recording geographical positions and thus the variation in speeds during trips. Linking GPS data to spatial data sources adds features that vary during the trip. Multilevel mixed-effects models were estimated to test the influence of factors at cyclist, trip and tracking point levels. Results show that individuals who prefer a high speed have a higher average personal speed. Longer trips and trips made by conventional electric bicycles and sport bicycles have a higher average trip speed. Tracking point level variables explain intra-trip cycling speed variations. Light-medium precipitation and tailwind increase cycling speed, while both uphill and downhill cycling is relatively slow. Cycling in natural and industrial areas is relatively fast. Intersections, turns and their adjacent roads decrease cycling speed. The higher the speed, the stronger the influence of infrastructure on speed. Separate bicycle infrastructure, such as bike tracks, streets and lanes, increase speed. These findings are useful in the areas of cycling safety, mode choice models and bicycle accessibility analysis. Furthermore, these findings provide additional evidence for smooth cycling infrastructure construction.

Controlling the weld penetration depth of laser beam micro welding by using an iterative learning approach

AbstractIn order to meet the increasing demand for high‐speed joining processes, laser beam micro welding is used to reproducibly weld metallic joining partners such as steel. Long weld seams or high cycle speeds, however, remain a challenge to achieve a constant welding depth throughout the entire welding process without major fluctuations. This paper shows the development and evaluation of a weld penetration depth control system based on interferometric measurement of the depth of the vapor capillary. High path speeds and small weld depths are challenging for real‐time depth control. Therefore, the offline data of the interferometric measurements are used to implement an iterative learning control of the weld penetration depth. The quality of the control is verified by welding with and without spatial power modulation on 1.4301 steel while following a linear and sinusoidal trajectory.

Industrial Internet of Things Gateway with OPC UA Based on Sitara AM335X with ModbusE Acquisition Cycle Performance Analysis.

This article presents the hardware and software architectures used to implement the Modbus Extension (ModbusE) IIoT gateway, the performance of the acquisition cycle at the PRU real-time programmable core level, the acquisition cycle communication flow-dispatcher-OPC UA server (Linux)-OPC UA client (Windows) as well as the performance analysis of data communications between the IIoT ModbusE gateway and the OPC UA client (Windows). In order to be able to implement both the ModbusE acquisition cycle and the OPC UA server, the BeagleBone Black Board was chosen as the hardware platform. This board uses the Sitara AM335x processor (Texas Instruments (TI), Dallas, TX, USA) from Texas Instruments. Thus, the acquisition cycle was implemented on the PRU0 real-time core, and the OPC UA server, running under the Linux operating system, was implemented on the ARM Cortex A8 processor. From the analysis of the communication speed of the messages between the OPC UA client and the ModbusE servers, it was found that the ModbusE acquisition cycle speed was higher than the acquisition speed of the OPC UA client.

3D rolling contact finite element analysis of high-speed railway turnout considering ratchetting effect

The present work introduces a three-dimensional finite element model for the wheel-turnout-sleeper system, incorporating a cyclic constitutive model that accurately captures the nonlinear hardening behavior of rail steel under cyclic loadings. At the same time, a mixed implicit-explicit finite element method is employed to investigate the transient rolling contact behavior of wheel-turnout. Through dynamic analysis, the transient rolling contact status of the wheel-turnout, stress and strain responses of the turnout, and wheel-rail forces are investigated under varying crossing speeds and number of cycles. It is found that during the wheelset crossing, the contact stress remains relatively stable on the stock rail, and multi-point contact occurs at the wing rail and long point rail, and the contact stress on the surface of the long point rail is more significant. With an increase in crossing speed in the same cycle, there is a gradual rise in contact stress on the long point rail face. At the same crossing speed, with the increase in the number of cycles, the contact position between the wheelset and the long point rail gradually moves back, and the top width of the contact position gradually expands. Meanwhile, the fluctuation range of vertical displacement of the wheel center diminishes, and the wheel flange moves away from the long point rail. Additionally, a progressive accumulation of ratcheting strain is observed on the rail, and the ratcheting strain on the long point rail significantly exceeds that on the stock rail. The research results will help to provide a reference for the optimization and design of the critical cross-section profile of the long point rail and will have guiding significance for the maintenance and repair of turnouts.

Effect of nerve growth factor on elderly degenerative knee osteoarthritis pain

To explore effect of nerve growth factor (NGF) antibody on knee osteoarthritis (KOA) pain model was evaluated by in vitro model. Thirty male SPF rats aged 28-week-old were divided into blank group (10 rats with anesthesia only). The other 20 rats were with monoiodoacetate (MIA) on the right knee joint to establish pain model of OA, and were randomly divided into control group (injected intraperitoneal injection of normal saline) and treatment group (injected anti-NGF) intraperitoneal after successful modeling, and 10 rats in each group. All rats were received retrograde injection of fluorogold (FG) into the right knee joint. Gait was assessed using catwalk gait analysis system before treatment, 1 and 2 weeks after treatment. Three weeks after treatment, right dorsal root ganglia (DRG) were excised on L4-L6 level, immunostained for calcitonin gene-related peptide (CGRP), and the number of DRGS was counted. In terms of gait analysis using cat track system, duty cycle, swing speed and print area ratio in control and treatment group were significantly reduced compared with blank group (P<0.05). Compared with control group, duty cycle and swing speed of treatment group were significantly improved (P<0.05), and there was no significant difference in print area ratio between treatment group and blank group (P>0.05). The number of FG-labeled DRG neurons in control group was significantly higher than that in treatment group and blank group (P<0.05). The expression of CGRP in control group was up-regulated, and differences were statistically significant compared with treatment group (P<0.05). Intraperitoneal injection of anti-NGF antibody inhibited gait injury and upregulation of CGRP in DRG neurons. The results suggest that anti-nerve growth factor therapy may be of value in treating knee pain. NGF may be an important target for the treatment of knee OA pain.