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Though the component of threshing drum is pre-balancing on the factory, the drum after assembly still has the problem of unbalanced vibration. In this study, the unbalance mechanism produced by assembly are introduced and the centroid propagation model in the series rotation system was established. The influence of the eccentricity and assembly phase on the assembly unbalance was studied. It is shown that there was a superposition effect between the initial centroid eccentricity caused by the machining error and the centroid eccentricity caused by assembly error, the unbalance amount under the in-phase assembly was larger than that of the anti-phase assembly. Moreover, the unbalance variation was experimentally investigated using in-field balancing detection on the test rig and combine harvester. The experiment results showed the excellent vibration reduction effect of in-field balancing, which showed a reduction of 83.0% and 85.8%. In order to increase the range of in-field balance detection and reduce the calculation error, the double-speed influence coefficient method was proposed. The proposed method adopted the way of first low-speed pre-balancing, and then high-speed precision balance, taking advantage of vibration information at two speeds and avoids nonlinear vibration conditions caused by high unbalanced vibration. Finally, the doublespeed influence coefficient method was verified on the test rig. The vibration reduction effect of proposed method was better than the traditional method. [ABSTRACT FROM AUTHOR]

In this paper, the basic rigid unit and discrete element rigid model of reed stem and discrete element flexible model of reed stem were established by means of multi-spherical filling and other methods. Then, three-point bending test was carried out in EDEM software to complete the calibration of bonding parameters. Finally, simulation analysis was carried out with the loss rate as the index. The simulation results show that the optimal parameter combination is 46 r/min for the transverse transmission device, 53 r/min for the vertical clamping longitudinal transmission device, and 470 mm for the center distance of the drum. Finally, the initial field test verifies that the maximum parameter combination of the harvester header is 49 r/min for the transverse conveying device of the header, 51 r/min for the vertical clamping longitudinal conveyor and 1.1 m/s for the field forward speed of the reed harvester, and the loss rate of the harvester is 3.36%, and the optimal parameter combination is consistent with the simulation analysis results. [ABSTRACT FROM AUTHOR]

The value of high moisture content crops is higher and the planting area is wider. However, in the harvest process, due to the high moisture content, the cleaning loss is greater. In order to reduce the adhesion between the crop extraction mixtures and improve the cleaning performance, a method of hot air cleaning was proposed. By using the fan design theory and thermodynamics, the prototype design of the hot air fan was completed. Through orthogonal test, the most suitable parameter combination is 1445 r/min fan speed and 85℃ air inlet temperature. Computational fluid dynamics (CFD) was used to observe the air velocity and air temperature of the outlet under the optimal combination of parameters to check whether it meets the requirements of hot air cleaning. The reliability of numerical simulation was tested by bench test. Finally, a field experiment was carried out with the hot air fan to observe the difference between the cleaning effect and the fan under the optimal parameter combination, and compare the cleaning loss rate. [ABSTRACT FROM AUTHOR]

In view of the fact that the threshing gap of combine harvester can only be controlled by adjusting gravure screen and it is time-consuming and laboring, a kind of variable-diameter threshing drum with movable radial plates is developed by changing the diameter of threshing drum to adjust the threshing gap concentrically. All parts of the threshing drum were designed and checked by mechanical design principle, and the statics and modal analysis of the whole structure were carried out by ANSYS Workbench. The results show that the maximum deformation of the variable-diameter threshing drum with movable radial plates is 0.29 mm under boundary conditions. The maximum allowable deformation of the threshing drum in use is 3 mm, which meets the requirements of use. The equivalent stress of the threshing drum with variable diameter is up to 100 MPa, which is less than the yield strength of the material, and will not cause structural damage. According to the modal analysis, the natural frequency of the threshing drum does not cause resonance phenomenon. The field test of wheat was carried out after the processing of the variable-diameter threshing drum with movable radial plates was installed, and the working performance was compared with that of the ordinary drum. The results showed that the threshing performance was the best when the forward speed was 1 m/s, the grain entrainment loss rate was 0.53%, and the grain un-threshed rate was 0.065%. The grain breakage rate is 0.54%, and the performance is more than 50% higher than that of ordinary rollers. It lays a foundation for the adaptive adjustment of threshing gap in combine harvester. [ABSTRACT FROM AUTHOR]

In this paper, BP neural network is used to collect header height, AMEsim is used to simulate and analyze header height adjustment hydraulic system, and fuzzy PID control is used to adjust header lifting hydraulic cylinder to stabilize header height. The experimental results of harvesting different crops show that under the header height automatic control system, the error between the actual height of crop harvesting and the set height is within 15 mm, and the harvesting effect is good, which can meet the automatic regulation requirements of the header height of the multi crop combine harvester. [ABSTRACT FROM AUTHOR]

It is generally accepted the vegetation of the North-Western Caspian Plain include to the desert zone. The purpose of the article is to justify the belonging of the vegetation of this area to the steppe zone. The descriptions of vegetation on ecological-topological profiles on three key sites carried out in 1961 and 2008 are compared. Comparative analysis of plant communities revealed changes that occurred in almost half a century. It is established that the composition of the vegetation remains the presence the steppe turf grasses on light chestnut and brown-steppe soils and extra zonal of xero-halophytes on solonetz soils. The constant participation of turf grasses in the addition of communities gives grounds to refer the vegetation cover of the North-Western Caspian Plain to the subzone of the southern desert steppes of the steppe zone. [ABSTRACT FROM AUTHOR]

Determination of the mechanical properties (rupture force, deformation, hardness, and toughness) of maize grain could be a significant concern for designing the harvester, thresher, and handling, processing, and storage equipment. Thus, the present research was conducted to assess the vertical and lateral rupture force, deformation, hardness, and toughness of maize grain (Beijing Denong, Lianchuang, Suyu 20, Liyu 88 and Suyu 29) influenced by different moisture contents (11.2%, 17.5%, and 21.3%) and compressive loading speeds (5, 10, 15, 20, and 25 mm/min, respectively). Besides, the mean length, width, thickness, geometric mean diameter, equivalent diameter, arithmetic diameter, sphericity, grain volume, surface area, and aspect ratio of the selected varieties were measured. The results showed that the highest length, width, thickness and sphericity, grain volume, surface area, and aspect ratio were obtained at moisture of 21.3%, whereas the lowest was at 11.2%. Moreover, it was observed that as increasing the loading speed from 5 to 25 mm/min, the vertical and lateral rupture forces decreased. However, as increasing moisture contents from 11.2% to 21.3%, the vertical and lateral rupture forces, hardness, and toughness decreased noticeably. Furthermore, the maximum correlation (R2=0.9957) between rupture force and loading speed was found for Liyu 88 at moisture of 17.5% and minimum correlation (R2=0.7002) was found for Suyu 29 at moisture of 11.2%. Moreover, the highest lateral and vertical rupture force was noticed (p<0.05) at a loading speed of 5 mm/min. Based on the experimentally obtained results, it was concluded that the properties of maize grain evaluated were relevant to the design of planter, harvesters, thrashers, and processing machine. [ABSTRACT FROM AUTHOR]

In order to study the influence of the side drive on the balance state of the threshing drum, this paper used the side eccentric load chain drive as the power on the threshing drum dynamic balance test bench. By analyzing the influence of different radial phases, different axial distances, and spiral combinations of the threshing drum on the counterweight, this paper studies the law of the effect of side partial load chain drive on the dynamic balance of the threshing drum and finds that the side chain drive has obvious influence on the unbalance phase of the threshing drum and the change of the axial distance of unbalance has little effect on the equilibrium state of the threshing drum. And from this, a vibration balance method based on the equivalent unbalance of the chain drive is proposed, which can predict and calculate the unbalance of the threshing drum. The unbalance of the threshing drum predicted by this method is smaller than the actual measured unbalance. The maximum error is 32.64% and the minimum error is 4.6%. In the two tests, the predicted unbalance is 1.24 mm/s in amplitude and 270 degrees in phase and amplitude 1.4 mm/s and phase 120 degrees, respectively. The measured unbalance is amplitude 1.587 mm/s and phases 286 degrees. The error between prediction and actual measurement is less than 32.64%, and the unbalance amplitudes that can be reduced by one-time dynamic balance are 0.856 mm/s and 0.674 mm/s, respectively. The research results in this paper provide an effective method for the balance state of the multidrum side chain transmission. [ABSTRACT FROM AUTHOR]

A knowledge-based fuzzy logic model was developed on experimental data and used to predict the draft, side and vertical forces and soil disturbance area by disc tillage tool operation. The laboratory research work was conducted to evaluate the performance of the disc tool at three working speeds (1.25 m/s, 1.98 m/s and 2.47 m/s, respectively) and depths (0-5 cm, 5-10 cm and 10-15 cm, respectively) on paddy soil under soil-bin environment. Further, draft (Fx), side (Fz) and vertical (Fy) forces of disc and soil disturbance area were assessed and predicted towards working speeds and depths. A fuzzy prediction model with two input variables (speed and depth) and four output variables was developed and the Mamdani inference approach was used. Draft, side and vertical forces of disc and soil disturbance area were positively responded 0.97, 0.95 and 0.84 and 0.99, respectively. The prediction results showed a close relationship between measured and predicted data. Similarly, the measured and predicted results revealed that the draft, side, vertical forces, and soil disturbance area slightly increased, while increasing the speed and depth of the disc tool. Furthermore, disc forces and soil disturbed area were highly significant (p<0.05) for higher speed towards depth. It was concluded that the fuzzy model may be introduced for predicting the disc forces and soil disturbance area during the disc tillage tool operation with high accuracy. [ABSTRACT FROM AUTHOR]

Mechanical shear resistance of wheat grain is a significant concern for the designers and researchers related to the design of threshing, handling and processing machinery of the field crops. The grain mechanical properties directly affect the machine geometry and its operational parameters. The present study was carried out to determine the shear resistance of five wheat varieties (Locally names; TD-02, Sindhu-1105, Benazir, China and SKD-118) influenced by moisture content (16.7%, 18.7% and 19.5%) and loading rate (3 mm/s, 6 mm/s and 9 mm/s). However, some physio-dimensional properties (length, width, thickness, slenderness ratio, surface area and sphericity) were obtained at different moisture contents. The results showed that the shear resistance reduced by increasing the moisture content and loading rate. The average shear resistance decreased from 10.45 N to 3.74 N for 3-9 mm/s loading rate at moisture content of 16.7% to 19.5%. Thus, the maximum correlation (r = 0.905) of shear resistance obtained at 16.7%, whereas minimum correlation (r = 0.692) obtained at 19.5%. The shear resistance of wheat grain was highly significant (p<0.05) at 9 mm/s for 19.5%. Shear resistance decreased with an increase in the moisture content in the grain whereas deformation is increasing with the increase of moisture content. However, the maximum bulk density of wheat grain obtained at 19.5% for SKD-118, while the minimum obtained at 16.7% for TD-02. It is recommended that the design and modification of wheat grain processing equipment should be executed on the physio-mechanical properties of grain varieties. [ABSTRACT FROM AUTHOR]

Grain sieve losses are important parameters to judge the performance of cleaning shoes in combine harvesters. To keep grain sieve loss within acceptable limits, an impact-type piezoelectric sensor was developed for real-time monitoring. Rice grain and short straw particle models were established according to their physical properties, and discrete element method (DEM) simulations were carried out to understand their collision behaviour with the sensor. The influence of grain shape, straw length and impact angle on variations of the maximum normal contact force and force rise-time were analysed in detail. Differences in normal collision force, and force rise-time occurred which lead to corresponding differences in signal frequency and voltage amplitude. A signal processing circuit, which mainly consisted of a band-pass filter circuit and a voltage comparator circuit, was designed to discriminate for full grains. Field tests results indicated that measurement errors recorded by the sensor and checked against manually measurements were <4.48%.Highlights· Collision behaviour of rice grain and straw with the sensor was studied utilizing DEM simulations. · A signal processing circuit was designed to discriminate for rice grains. · Field tests results indicated that measurement errors of the developed sensor were <4.48%. [ABSTRACT FROM AUTHOR]

Warming and grazing significantly affect the structure and function of an alpine meadow ecosystem. Yet, the responses of soil microbes to these disturbances are not well understood. Controlled asymmetrical warming (+1.2/1.7°C during daytime/nighttime) with grazing experiments were conducted to study microbial response to warming, grazing and their interactions. Significant interactive effects of warming and grazing were observed on soil bacterial α-diversity and composition. Warming only caused significant increase in bacterial α-diversity under no-grazing conditions. Grazing induced no substantial differences in bacterial α-diversity and composition irrespective of warming. Warming, regardless of grazing, caused a significant increase in soil bacterial community similarity across space, but grazing only induced significant increases under no-warming conditions. The positive effects of warming on bacterial α-diversity and grazing on community similarity were weakened by grazing and warming, respectively. Soil and plant variables explained well the variations in microbial communities, indicating that changes in soil and plant properties may primarily regulate soil microbial responses to warming in this alpine meadow. The results suggest that bacterial communities may become more similar across space in a future, warmed climate and moderate grazing may potentially offset, at least partially, the effects of global warming on the soil microbial diversity. [ABSTRACT FROM AUTHOR]

Grain separation losses is a key parameter to weigh the performance of combine harvesters, and also a dominant factor for automatically adjusting their major working parameters. The traditional separation losses monitoring method mainly rely on manual efforts, which require a high labor intensity. With recent advancements in sensor technology, electronics and computational processing power, this paper presents an indirect method for monitoring grain separation losses in tangential-axial combine harvesters in real-time. Firstly, we developed a mathematical monitoring model based on detailed comparative data analysis of different feeding quantities. Then, we developed a grain impact piezoelectric sensor utilizing a YT-5 piezoelectric ceramic as the sensing element, and a signal process circuit designed according to differences in voltage amplitude and rise time of collision signals. To improve the sensor performance, theoretical analysis was performed from a structural vibration point of view, and the optimal sensor structural has been selected. Grain collide experiments have shown that the sensor performance was greatly improved. Finally, we installed the sensor on a tangential-longitudinal axial combine harvester, and grain separation losses monitoring experiments were carried out in North China, which results have shown that the monitoring method was feasible, and the biggest measurement relative error was 4.63% when harvesting rice. [ABSTRACT FROM AUTHOR]

A triaxial ellipsoidal particle model was established according to the physical properties of rice seed, and its impact behaviour against a grain loss sensor was simulated using the discrete element method (DEM). The contact criterion was developed directly by solving the intersection equations, and the contact forces were calculated according to elastic–plastic and Mindlin models. It was shown that the seeds may perform translational and rotational motion in a 3D space after the impact. With the influences of particle shape, orientation and angle of incidence, three typical impact processes were found: single impact, multiple impacts in a short-time, and continuous impacts. Two important parameters for the design of loss sensors are the maximum normal impact force F n max and the force rise-time t r. Simulations showed that an increase in particle ellipticity strongly enlarged the differences in F n max. As the ellipticities increased from unity to 2, the defined force ratio η decreased from 100% to about 40%, and this value decreased to less than 20% when ellipticities continuously increased from 2 to 4. Tangential velocity led to an asymmetric variation of η. t r was generally distributed between 12 and 54 μs. In laboratory tests, rice seeds were allowed to free fall onto a loss sensor from a height of 320 mm. Results indicated that the peak output voltage was fluctuated in 1.5–4.5 V, and the rise-time was in 14–48 μs. [Copyright &y& Elsevier]

Impact damage is the main form of rice threshing and it is also a significant cause of rice injury. Based on contact mechanics, models of the compressed displacement and the largest pressure distribution were established for the case when the threshing tooth obliquely impacts against the rice kernel. A critical velocity formula for impact damage was developed. A computer-aided design model of a rice kernel comprising of three layered ellipsoids was established. HyperMesh software was used to partition mesh elements and to set material and contact parameters for each element, constructing a finite element model for the analysis. Using LS-DYNA software, the impact between the threshing tooth and the rice kernel was simulated and analysed. The simulation showed that the rice husk was subjected to tensile stresses. Tensile stress was a maximum at the front of the contact zone and shifted continuously. The entire kernel rolled during impact. The critical damage velocity for the kernel, corresponding to the critical von Mises stress was 29.5 m s−1, which was in agreement with experimental results. [Copyright &y& Elsevier]

Background: Japanese encephalitis (JE) caused by Japanese encephalitis virus (JEV) accounts for acute illness and death. However, few studies have been conducted to unveil the potential pathogenesis mechanism of JEV. Dendritic cells (DCs) are the most prominent antigen-presenting cells (APCs) which induce dual humoral and cellular responses. Thus, the investigation of the interaction between JEV and DCs may be helpful for resolving the mechanism of viral escape from immune surveillance and JE pathogenesis. Results: We examined the alterations of phenotype and function of DCs including bone marrow-derived DCs (bmDCs) in vitro and spleen-derived DCs (spDCs) in vivo due to JEV P3 wild strain infection. Our results showed that JEV P3 infected DCs in vitro and in vivo. The viral infection inhibited the expression of cell maturation surface markers (CD40, CD80 and CD83) and MHCI, and impaired the ability of P3-infected DCs for activating allogeneic naïve T cells. In addition, P3 infection suppressed the expression of interferon (IFN)-α and tumor necrosis factor (TNF)-α but enhanced the production of chemokine (C-C motif) ligand 2 (CCL2) and interleukin (IL)-10 of DCs. The infected DCs expanded the population of CD4+ Foxp3+ regulatory T cell (Treg). Conclusion: JEV P3 infection of DCs impaired cell maturation and T cell activation, modulated cytokine productions and expanded regulatory T cells, suggesting a possible mechanism of JE development. [ABSTRACT FROM AUTHOR]

The performance of a vacuum-cylinder seeder for the precision sowing of rape seeds was investigated. For releasing seeds from nozzles smoothly, a positive differential pressure was applied to the seed. The forces acting on the seeds in free flight were calculated using the computational fluid dynamics (CFD) software Fluent. Using the differential equation for seed motion, seeds falling trajectories using different working parameters were numerically determined. A high-speed camera system mounted on a laboratory seeder test-rig was used to record the motion of seeds. A mean shift algorithm for tracking seeds was used. The horizontal displacement x and the fall time t f of seeds predicted by the numerical analysis and measured by the high-speed camera system were compared. The results indicated that the relative errors of x and t f were <5.5% and 6.5%, respectively, indicating good agreement. Based on the analysis of seeds falling trajectories, it was found that the variations of positive differential pressure Δp and release angle θ had significant effects on seeding uniformity. In order to analyse their effects on horizontal displacement, a coefficient of positive differential pressure variation χ p and coefficient of sowing angle variation χ θ were proposed and their values calculated. Calculations indicated that the optimum levels for Δp and θ for the precision seeding of rape seeds were in the range of 1–2kPa and from −10 to 0°, respectively. Experiments were carried out on the vacuum-cylinder precision seeder test-rig and the results showed that the average seed spacing interval error reached the minimum at Δp =1.5kPa and θ =−5° and that the error increased almost linearly with increasing of cylinder rotational speed. [Copyright &y& Elsevier]

Abstract: The giant magneto-impedance (GMI) effect was observed in almost zero-magnetostrictive Co66.3Fe3.7Si12B18 amorphous ribbon toroidal cores after annealed by a 25A/mm2 pulse current density under a transverse magnetic field of 2kA/m for 30s. A maximum GMI ratio of 34% and a sensitivity of about 65%/Oe were measured employing a 900kHz sharp pulse current generated by a CMOS inverter multivibrator. A sensitive non-contact type current sensor composed of an amorphous ribbon toroidal core connected with a pulse current generator, a peak detector, and a differential amplifier is presented. The sensor is able to examine the value and direction of dc current. The measurement accuracy of 0.45% and sensitivity of 0.67V/A were obtained with full scale ±2.5A using a power source voltage of 5V. [Copyright &y& Elsevier]

Vacuum-vibration precision seeding technology is a crucial technology that affects the industrialization process of super rice plug seedlings. To solve the problems that the vibrating supply seed tray structure in a vacuum-vibration precision seeder caused the vibration of the whole machine and the decline of the seeding eligible rate under high frequency and large amplitude vibration, it is important to design a new supply seed tray structure. This research proposed a method to make the seeds "boiling" under the combined effect of air blowing and vibration, and designed the air-blowing and vibrating supply seed tray structure. FLUENT was used to analyze fluid motion inside the supply seed tray and optimize the structure parameters of the supply seed tray. The maximum airflow velocity was determined when the inlet air pressure was 22 kPa, the number of air inlets was 2, and the diameter of the holes at the bottom of the supply seed tray was 2 mm. Comparative experiments were carried out to prove the air-blowing and vibrating supply seed tray structure could reduce the vibration frequency by 1.5 Hz and decrease the amplitude by 0.25 mm. The mathematical regression models between the inlet air pressure, vibration frequency, amplitude, and seeding performance indexes were established by orthogonal experiments. Through the optimization operation and bench tests, it was determined that when the inlet air pressure was 19.49 kPa, the vibration frequency was 9.00 Hz, and the amplitude was 2.65 mm, the eligible rate, replay rate, and hole rate could reach 93.56%, 3.35%, and 3.09%. The experimental results were generally consistent with the predicted values. The research confirmed that the air-blowing and vibrating supply seed tray could improve the eligible rate while reducing the vibration frequency and amplitude of the vacuum-vibration tray precision seeder. It also provided a necessary basis for precision seeding technology. [ABSTRACT FROM AUTHOR]

Flavivirus protease has been deemed a potential target for drug and therapeutics development due to its crucial role in viral replication. In this study we prepared a monoclonal antibody (mAb) against nonstructural protein 3 (NS3) protease portion of Japanese encephalitis virus (JEV), and evaluated its inhibitory effect for NS3 protease activity. First, a JEV NS3 protease-specific mAb (designated 2C2) was generated by the traditional cell fusion technique. Second, the binding specificity of 2C2 for NS3 protease was determined by indirect fluorescent assay and Western blotting. Finally, inhibitory effect of 2C2 for NS3 protease cleaving human stimulator of interferon gene was evaluated. Therefore, mAb 2C2 provides a potential diagnostic tool for differential diagnosis for patients who have been vaccinated with inactivated vaccine or naturally infected, and might be genetically reconstructed and optimized for new therapeutics development. [ABSTRACT FROM AUTHOR]

Grain damage research has been a focus of many experts in the agriculture machinery industry. A threshing test-bed was developed to investigate the movement and influence of different threshing and separating units on maize grains. The damage to maize grains was analyzed with a high-speed camera to observe the movement and damage received by the maize grains. The results showed that the threshing and separating effects of the perforated concave plate were obviously lower than that of the round steel concave plate, the threshing effects of the rigid rasp bar and polyurethane rasp bar were similar, and the damage ratio of the polyurethane rasp bar was relatively low. It also indicated that moisture content has a significant effect on the damage ratio and damage type of maize grains. The different threshing component types used in this study had an obvious effect on the degree of damage to high moisture content maize grains and the damage to high-moisture kernels during threshing could be further identified. The results can provide a reference for the design of threshing and separating devices in the maize combine harvesting machinery. [ABSTRACT FROM AUTHOR]

To ensure the stable driving of tracked robots in a complex farmland environment, an adaptive backstepping control method for tracked robots was proposed based on real-time slip parameter estimation. According to the kinematics analysis method, the kinematic model of the tracked robot was established, and then, its pose error differential equation was further obtained. On this basis, the trajectory tracking controller of the tracked robot was designed based on the backstepping control theory. Subsequently, according to the trajectory tracking error of the tracked robot, the back propagation neural network (BPNN) was used to adaptively adjust the control parameters in the backstepping controller, and the inputs of the BPNN are the trajectory tracking error xe, ye, θe. After that, the soft-switching sliding mode observer (SSMO) was designed to identify the slip parameters during the running of the tracked robot. And then the parameters were compensated into the adaptive backstepping controller to reduce the trajectory tracking error. The simulation results show that the proposed adaptive backstepping control method with SSMO can improve the accuracy of the trajectory tracking control of the tracked robot. Additionally, the designed SSMO can accurately estimate the slip parameters. [ABSTRACT FROM AUTHOR]

This paper mainly studied the working environment modeling and coverage path planning of combine harvesters. The boundaries of the farmland to be harvested were extracted through the farmland satellite imagery and canny algorithm. The polygon approximation method was used to fit the extracted boundaries as polygons. The edge offset of the farmland and obstacles was realized based on the principle of straight skeleton. According to the structure data of the split points which were obtained through the improved scan line algorithm, the coverage path planning of the combine harvester was realized. Moreover, the circular arc transition algorithm was used to optimize the harvesting paths to achieve the smooth turning of the combine harvester at the edge of farmland and when encountering obstacles. The simulation results show that the proposed the proposed polygon approximation method can accurately depict the boundaries of the farmland to be harvested, and reduce the amount of data to be stored. Additionally, the designed path planning method can realize the coverage path planning of the combine harvester in irregular and internal obstacle farmland. [ABSTRACT FROM AUTHOR]

With the advancement of agricultural mechanization and the development of combine harvesters, cleaning devices play a very important role in the grain harvesting process. In this study, the DFPF-25 type material floating velocity measuring device was used to measure the suspension velocity of each component of the grain material. Secondly, the DFQX-3 cleaning device was used to conduct the airflow field test, then the fluid simulation of the cleaning shoe was carried out. The results showed that the simulation and experimental results were in a good agreement under the conditions of single fan and double fan. The high-speed flow velocity formed by the double fan system at the tail of the cleaning shoe was 4.76 m/s (simulation) and 4.03 m/s (experiment), which had outstanding cleaning effects on unfilled grains, long stems, and short stems. To sum up, the installation of the cross-flow fan at the rear of the cleaning shoe has a positive effect on the cleaning effect of the combine harvester, and the double-fan cleaning structure composed of the cross-flow fan and the centrifugal fan can significantly improve the cleaning effect. [ABSTRACT FROM AUTHOR]

Based on the working principle of magnetorheological fluid damping, in this paper, a set of squeezing mode Magneto-rheological Fluid (MRF) dampers is designed for drilling vibration suppression in deep hole machines. Elaborate analysis of the correlativity between the dynamic morphology trajectory of the machined hole surface, the vibration of the drilling tool-shaft, and the theoretical derivation of the damping force, is put forward in accordance with the Bingham model and Euler-Bernoulli beam Equation. Simultaneously, the contrast analysis of the vibration suppression effect is carried out through the drilling experiments with and without an MRF damper. In addition, a series of measurements on the vibration characteristics of the drilling shaft, the drilling tool and the guide surface wear patterns, and the machine hole surface are analyzed, respectively. Both the drilling experiments and theory studies have revealed that the strength of the magnetic field changed with the drill shaft at different levels of vibration. The MRF damper could suppress the vibration with nonlinear characteristics initiatively and instantaneously, by variable damping, which can eventually improve the surface roughness. In addition, according to the phenomenon of tool tipping, the breakage of the guide bars and the machine hole surface deduces the condition of the vibration effect objectively. [ABSTRACT FROM AUTHOR]

During the baling operation, the wheat stalks are subjected to various mechanisms in the baler and the main form is compression. After the wheat stem is forced by a combination of the threshing cylinder, it needs to be formed under the action of straw baler and meet transport requirements. This paper mainly studies the properties of wheat stalks when baling, and proposes the application of the creep after-effect theory during the baling process. The tension-compression tester is used to perform 50 mm stalk mechanical test, 50 mm stalk static pressure test, 35 mm×40 mm×50 mm stalk module static pressure test and bale static pressure test. The measured elastic modulus of the stem sample is 7.59 MPa, and the elastic modulus of the inner core of the stem is 8.24 MPa. The return curve of the single stalk and the bale is consistent with the initial creep and steady-state creep in the creep after-effect theory. A logarithmic function was used for fitting of the first stage with coefficient of determination R2 = 0.8364, and a linear function was used for fitting of the second stage with coefficient of determination R2 = 0.9921. The high water content static pressure test suggests that the load in the loading direction is the coupled load of the working load of the hydraulic cylinder and the internal stress of the bale. When harvesting wheat stalks with high moisture content, the density parameter of the bale can be appropriately increased while the load parameter of the hydraulic cylinder can be considered unchanged or even reduced. The adjustment of density and load can still ensure the forming quality of the bale. [ABSTRACT FROM AUTHOR]

In view of the current large rapeseed header losses of rape combine harvesters, the effects of the header on rapeseed header loss were studied from the perspective of vibration. First, the vibrations at various measuring points on the header during rape harvest were studied using a data acquisition and analysis system while performing collection tests of rapeseed header loss with the sample slot method. The relationships between total header vibration and total rapeseed header loss and between vertical cutter vibration and rapeseed vertical cutter loss were shown to have a positive correlation, and they all increased with the increase in engine speed. Vertical cutter loss accounted for 31.2% to 42.4% of the total rapeseed header loss. Modal analysis and optimization of the header frame were then performed by simulation and test. The natural frequencies of the first-order and second-order modes of the optimized header were increased, and the possibility of resonance with other working parts was eliminated. Finally, the improved header was tested during rape harvest. The results showed that the total vibration of the improved header was reduced by 19.9% to 43.9%, and the total rapeseed header loss was reduced by 33.2% to 46.9%. The vertical cutter vibration was reduced by 30.5% to 49.8%, and the rapeseed vertical cutter loss was reduced by 20.8% to 34.7%. In addition, the vibration and rapeseed loss of the improved header had relatively slow rates of increase with the increase in engine speed. The method of reducing rapeseed loss by reducing the header vibration achieved an obvious and positive effect. [ABSTRACT FROM AUTHOR]

The article discusses osteosarcoma has the common type of bone cancer and the second leading cause of cancer-related deaths in children and adolescents. Topics include cancer stem cells (CSCs) have involved in tumorigenesis, recurrence, and therapy resistance; and to identify critical regulators of sarcoma CSCs, performed a reporter-based genome-wide CRISPR-Cas9 screen.

During the threshing process of rice, the grains fall off the head of the rice ear due to the impact of the threshing bar. At the same time, the impact force of the threshing element causes a certain degree of damage to the grain. However, there are relatively few methods to analyze the internal damage of rice grains during the threshing process. In this study, the connection force between rice grains and stalks and the compressive bearing capacity of the grains were tested on a push-pull test machine, and then the critical impact force and velocity of rice grains during plastic deformation and brittle fracture were obtained by Hertz theory. On this basis, the quantitative evaluation model of grain internal damage was established through the extraction and calculation of the damaged area inside the grain, and the damage degrees inside the grain under different loading times and loading forces were analyzed. The results showed that the average threshing force required for rice grains is 1.57 N (variance is 0.0529), and the critical impact forces for plastic deformation and brittle fracture of the grains during threshing are 138.79 N and 145.77 N. Since the threshing force during the threshing process was 43.9-71.9 N, it could be known from the internal damage model that the grain is in the safe loading area. Under the same load, the vertical pressure causes the most damage, the lateral pressure takes second place, and the positive pressure was the least. The results of this study can provide a basis for the development of combine harvester and rice grains damage evaluati [ABSTRACT FROM AUTHOR]

Soil compaction and accumulation are caused by crawler steering. Soil characteristics would affect the ability of crawler straight forward and steering in situ. This paper studied the principle of straight forward steering and steering in situ mode of traditional unilateral brake steering gearbox of a crawler combine harvester. Then a positive and negative steering gearbox model was developed and processed. The performance of positive and negative steering gearbox was analyzed by performing two steering modes on soil compaction effect. Results showed that the positive and negative steering gearboxes can achieve three operating modes, such as straight forward, unilateral brake steering, and positive and negative steering in situ. The positive and negative steering in situ was smooth and without soil accumulation phenomenon. When the crawlers center distance, crawler grounding length, crawler width were 1150 mm, 1620 mm and 450 mm respectively, the rolling area and the scratch free area of positive and negative steering gearbox were 5.37 m2 and 0.36 m2 respectively. However, the rolling area and the scratch free area produced by unilateral brake steering gearbox were 13.92 m2 and 1.88 m2 respectively, which was 8.55 m2 larger than that of positive and negative steering gearbox. The crawler with positive and negative steering gearbox has minor damage to paddy soil. This research can provide a theoretical basis for the smooth steering in situ and structural optimization of the crawler steering gearbox. [ABSTRACT FROM AUTHOR]

To improve the driving comfort of combine harvesters, driver seat low-frequency vibration and related driver ride-comfort problems were investigated on a Chinese CFFL-850 crawler-type full-feed combine harvester based on ISO2631. Driver vibration and driving seat transmission characteristics were measured under the following conditions: no-load idling, driving on the road, driving in the field, and simulated harvesting. The root mean square values composite vibration under four conditions were 3.63 m/s², 2.35 m/s², 3.34 m/s², and 2.67 m/s2 , respectively. For the same condition, the maximum root mean square scores of vibration component on driver whole-body occurred in the seat support surface (test point 1) and vertical direction (Z direction), which were 3.56 m/s², 2.05 m/s², 3.15 m/s², and 2.43 m/s², respectively. The test point 2 to test point 1 vertical-transfer function curve trends were nearly identical. Nearly all of the transfer coefficients were greater than 1 in the range of 1-50 Hz, therefore, the seat vibration attenuation performance was poor. Based on the analysis results, the driver seat structure was altered and a verification test was performed. The test results indicated that after an X-damping mechanism was installed, vibration acceleration, on the surface of the seat support under the road-driving conditions, decreased from 2.35 m/s 2 to 1.68 m/s2 . Under the simulated harvesting condition, the vibration acceleration decreased from 2.56 m/s2 to 1.46 m/s² . Nearly all of the seat vertical transfer coefficients were less than 1 within the frequency range of 1-80 Hz, therefore the dynamic comfort of the seat was ameliorated after structural improvement. [ABSTRACT FROM AUTHOR]

To reduce the inertial force of the oscillating sieve and return pan of a rice combine harvester, partial equilibrium was adopted. Firstly, based on the kinematic analysis of a slider-crank mechanism, the appropriate mass of counterweight intervals was achieved. Then, an ADAMS dynamic simulation was used to determine the optimum balance mass of the oscillating sieve and return pan individually. Considering the relative motion between the return pan and the oscillating sieve, the overall inertial force of the two parts would be reduced. The simulation results indicated that the optimum counterweight of the oscillating sieve was 15.5 kg based on an analysis of the movement tracks of the mass center and overall inertial force. The results also showed that the overall balance of inertial force not only reduced the counterweight but also decreased the overall inertial force of the oscillating sieve and return pan. Finally, a search for the most suitable crank initial angle of the return pan to reduce the overall inertial force and optimize the overall balance revealed three groups of initial angles: φ=0°, φ=45°, and φ=90°. The results indicated that arranging the initial angle of the crank of the oscillating sieve and return pan in the same position (φ=90°) was the most favorable for reducing the overall inertial force. In this situation, the optimum counterweight of the oscillating sieve was only 14.0 kg. The results can provide references for the design of the overall balance of the inertial force in the cleaning components of a combine harvester. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) are important endogenous gene regulators that play key roles in prostate cancer development and metastasis. However, specific miRNA expression patterns in prostate cancer tissues from Chinese patients remain largely unknown. In this study, we compared miRNA expression patterns in 65 pairs of prostate cancer and para-cancer tissues by RNA sequencing and found that miR-182-5p was the most up-regulated miRNA in prostate cancer tissues. The result was validated using realtime PCR in 18 pairs of prostate cancer and para-cancer tissues. In in vitro analysis, it was confirmed that miR-182-5p promotes prostate cancer cell proliferation, invasion and migration and inhibit apoptosis. In addition, the androgen receptor directly regulated the transcription of miR-182-5p, which could target to the 3'UTR of ARRDC3 mRNA and affect the expression of ARRDC3 and its downstream gene ITGB4. For the in vivo experiment, miR-182-5p overexpression also promoted the growth and progression of prostate cancer tumors. In this regard, we suggest that miR-182-5p may be a key androgen receptor-regulated factor that contributes to the development and metastasis of Chinese prostate cancers and may be a potential target for the early diagnosis and therapeutic studies of prostate cancer. [ABSTRACT FROM AUTHOR]

For over 30 years, HIV/AIDS has wreaked havoc in the world. In the absence of an effective vaccine for HIV, development of new anti-HIV agents is urgently needed. We previously identified the antiviral activities of the scorpion-venom-peptidederived mucroporin-M1 for three RNA viruses (measles viruses, SARS-CoV, and H5N1). In this investigation, a panel of scorpion venom peptides and their derivatives were designed and chosen for assessment of their anti-HIV activities. A new scorpion venom peptide derivative Kn2-7 was identified as the most potent anti-HIV-1 peptide by screening assays with an EC50 value of 2.76αg/ml (1.65 αM) and showed low cytotoxicity to host cells with a selective index (SI) of 13.93. Kn2-7 could inhibit all members of a standard reference panel of HIV-1 subtype B pseudotyped virus (PV) with CCR5-tropic and CXCR4- tropic NL4-3 PV strain. Furthermore, it also inhibited a CXCR4-tropic replication-competent strain of HIV-1 subtype B virus. Binding assay of Kn2-7 to HIV-1 PV by Octet Red system suggested the anti-HIV-1 activity was correlated with a direct interaction between Kn2-7 and HIV-1 envelope. These results demonstrated that peptide Kn2-7 could inhibit HIV-1 by direct interaction with viral particle and may become a promising candidate compound for further development of microbicide against HIV-1. [ABSTRACT FROM AUTHOR]

The induction of a strong mucosal immune response is essential to building successful HIV vaccines. Highly attenuated recombinant HIV vaccinia virus can be administered mucosally, but even high doses of immunization have been found unable to induce strong mucosal antibody responses. In order to solve this problem, we studied the interactions of recombinant HIV vaccinia virus Tiantan strain (rVTT-gagpol) in mucosal epithelial cells (specifically Caco-2 cell layers) and in BALB/c mice. We evaluated the impact of this virus on HIV antigen delivery and specific immune responses. The results demonstrated that rVTT-gagpol was able to infect Caco-2 cell layers and both the nasal and lung epithelia in BALB/c mice. The progeny viruses and expressed p24 were released mainly from apical surfaces. In BALB/c mice, the infection was limited to the respiratory system and was not observed in the blood. This showed that polarized distribution limited antigen delivery into the whole body and thus limited immune response. To see if this could be improved upon, we stimulated unpolarized budding of the virus and HIV antigens by treating both Caco-2 cells and BALB/c mice with colchicine. We found that, in BALB/c mice, the degree of infection and antigen expression in the epithelia went up. As a result, specific immune responses increased correspondingly. Together, these data suggest that polarized budding limits antigen delivery and immune responses, but unpolarized distribution can increase antigen expression and delivery and thus enhance specific immune responses. This conclusion can be used to optimize mucosal HIV vaccine strategies. [ABSTRACT FROM AUTHOR]