The tractive performance of a friction-based prototype track

In recent years, the interest in the design, construction and utilization of rubber tracks for agriculture and earth moving machinery has increased considerably. The development of such types of tracks was initiated by the efforts to invent a more environmentally friendly vehicle-terrain system. These tracks are also the result of the continuous effort to develop more cost-effective traction systems. A rubber-surfaced and friction-based prototype track was developed and mounted on the patented modification of a new Allis Chalmers four wheel drive tractor. The track is propelled by smooth pneumatic tyres by means of rubber-rubber friction and the tractive effort of the track is mainly generated by soil-rubber friction between the rubber surface of the track elements and terrain. The experimental track layer tractor, based on an Allis Chalmers 8070 tractor (141 kW) was tested on concrete and on cultivated sandy loam soil at 7.8%; 13% and 21% soil water content. The contact pressure and the tangential force on an instrumented track element, as well as the total torque input to one track, was simultaneously recorded during the drawbar pull-slip tests. Soil characteristics for pressure-sinkage and friction-displacement were obtained from the field tests by using an instrumented linear shear and soil sinkage device. By applying the approach based on the classical bevameter technique, analytical methods were implemented for modelling the traction performance of the prototype track system. Different possible pressure distribution profiles under the tracks were considered and compared to the recorded data. Two possible traction models were proposed, one constant pressure model, for minimal inward track deflection and the other a flexible track model with inward deflection and a higher contact pressure at both the front free-wheeling and rear driving tyres. For both models, the traction force was mainly generated by rubber-soil friction and adhesion with limited influence by soil shear. For individual track elements, close agreement between the measured and predicted contact pressure and traction force was observed based on the flexible track model. The recorded and calculated values of the coefficient of traction based on the summation of the traction force for the series of track elements were comparable to the values predicted from modelling. However, the measured values of drawbar pull coefficient were considerably lower than the predicted values, largely caused by internal track friction in addition to energy dissipated by soil compaction. The tractive efficiency for soft surface was also unacceptably low, probably due to the high internal track friction and the low travel speeds applied for the tests. The research undertaken identified and confirmed a model to be used to predict contact pressure and tangential stresses for a single track element. It was capable of predicting the tractive performance for different possible contact pressure values.Thesis (PhD (Argricultural Engineering))--University of Pretoria, 2007.Civil EngineeringUnrestricte

Calibration and Testing of Discrete Element Modeling Parameters for Fresh Goji Berries

This paper aims at the standard grading of fresh goji berries and develops a variable gap-type fresh goji berry grading machine. To establish a complete simulation model, the discrete element parameters of the model were calibrated by a combination of physical experiments and simulation experiments. The outline of the goji berry was extracted by the SFM-CMVS technique, and a goji berry model was obtained using the multi-spherical particle model filling method in the EDEM software. By designing the free-fall, suspension collision, slope slip, and slope rolling experiments, we obtained the discrete element simulation parameters: the inter-particle collision restitution coefficient was 0.158, the collision restitution coefficient of fresh goji berry–silicone rubber material was 0.195, the static friction coefficient of fresh goji berry–silicone rubber material was 0.377, and the rolling friction coefficient of fresh goji berry–silicone rubber material was 0.063. By designing the steepest ascent search and central composite design experiments with the angle of repose (AoR) value obtained from the physical experiment as the target value (31.27°), we determined the inter-particle static friction coefficient to be 0.454 and the inter-particle rolling friction coefficient to be 0.037. Validation tests were conducted on the calibrated discrete element modeling parameters, and the results showed that the established fresh goji berry model and the optimally calibrated parameter combination are effective for discrete element studies on fresh goji berries

Hierarchically nanostructured porous TiO2(B) with superior photocatalytic CO2 reduction activity

Hierarchically nanostructured, porous TiO2(B) microspheres were synthesized by a microwave-assisted solvothermal method combined with subsequent heat treatment in air. The materials were carefully characterized by scanning and transmission electron microscopy, X-ray diffraction, CO2 adsorption, and a range of spectroscopies, including Raman, infrared, X-ray photoelectron and UV-Vis spectroscopy. The hierarchical TiO2 (B) particles are constructed by ultrathin nanosheets and possess large specific surface area, which provided many active sites for CO2 adsorption as well as CO2 conversion. The TiO2 (B) nanostructures exhibited marked photocatalytic activity for CO2 reduction to methane and methanol. Anatase TiO2 and P25 were used as the reference photocatalysts. Transient photocurrent measurement also proved the higher photoactivity of TiO2(B) than that of anatase TiO2. In-situ infrared spectrum was measured to identify the intermediates and deduce the conversion process of CO2 under illumination over TiO2(B) photocatalyst

A direct Z-scheme g-C3N4/SnS2 photocatalyst with superior visible-light CO2 reduction performance

Highlights - SnS2 quantum dots anchored in situ on g-C3N4 by a simple one-step hydrothermal method. - The internal electric field between g-C3N4 and SnS2 was confirmed. - Internal-electric-field-induced direct Z-scheme g-C3N4/SnS2 charge transfer for enhanced photocatalytic CO2 reduction. - In situ FTIR analysis further proved the suggested photocatalytic mechanism. Abstract Photocatalytic reduction of CO2 to solar fuels is an ideal approach to simultaneously solve the global warming and energy crisis issues. Constructing a direct Z-scheme heterojunction is an effective way to overcome the drawbacks of single-component or conventional heterogeneous photocatalysts for photocatalytic CO2 reduction. Here, a novel type of direct Z-scheme g-C3N4/SnS2 heterojunction was constructed by depositing SnS2 quantum dots onto the g-C3N4 surface in situ via a simple one-step hydrothermal method. l-Cysteine not only acted as the sulfur source, but also grafted ammine groups onto g-C3N4 in the hydrothermal process, which greatly enhanced the CO2 uptake of the composite. XPS analysis and density functional theory (DFT) calculation show that electron transfer occurred from g-C3N4 to SnS2, resulting in the formation of interfacial internal electric fields (IEF) between the two semiconductors at equilibrium. As a result, Z-scheme charge transfer took place under photoexcitation, with the electrons in SnS2 combining with the holes in g-C3N4, which improved the extraction and utilization of photoinduced electron in g-C3N4. The g-C3N4/SnS2 hybrid shows superior photocatalytic CO2 reduction as compared with individual g-C3N4 and SnS2, which should be attributed to the IEF-induced direct Z-scheme as well as improved CO2 adsorption capacity. In situ FTIR spectra illustrate that HCOOH appeared as an intermediate during the CO2 conversion, which can only be generated by g-C3N4 according to the energy level of the photoinduced electrons, further confirming the Z-scheme configuration for the g-C3N4/SnS2 system

PLCE1 Promotes Esophageal Cancer Cell Progression by Maintaining the Transcriptional Activity of Snail

Esophageal cancer is among the most deadly malignant diseases. However, the genetic factors contributing to its occurrence are poorly understood. Multiple studies with large clinic-based cohorts revealed that variations of the phospholipase C epsilon (PLCE1) gene were associated with esophageal cancer susceptibility. However, the causative role of PLCE1 in esophageal cancer is not clear. We inactivated the functional alleles of PLCE1 by CRISPR/Cas9 genome editing technology. The resultant PLCE1 inactivated cells were analyzed both in vitro and in vivo. Our results showed that loss of PLCE1 dramatically decreased the invasion and proliferation capacity of esophageal carcinoma cells in vitro. Moreover, such PLCE1 inactivated tumor grafts exhibited significantly decreased tumor size in mice. We found that PLCE1 was required to maintain protein level of snail a key transcription factor responsible for invasion. Our further transcriptomic data revealed that deficient cells were significantly decreased in expression of genes enriched as targets of Snail. Strikingly, recovery of Snail protein at least partially rescued the invasion and proliferation capacity in PLCE1 inactivated cells. In ESCC clinical specimens, PLCE1 was correlated with tumor stage (P < .0001). Interestingly, PLCE1 expression was positively correlated Snail by immunohistochemistry in such specimens (P < .0001). Therefore, our functional experiments showed the essential roles of PLCE1 in esophageal carcinoma cells and provided evidences that targeting PLCE1 and its downstream molecules could be effective therapies for esophageal cancer

A Multicenter, Double-Blind, Randomized, Placebo-Controlled Trial to Evaluate the Efficacy and Safety of Duliang Soft Capsule in Patients with Chronic Daily Headache

Objective. To investigate the efficacy and safety of traditional Chinese medicine Duliang soft capsule (DSC) in prophylactic treatment for patients with chronic daily headache (CDH). Methods. A multicenter, double-blind, randomized, placebo-controlled clinical study was conducted at 18 Chinese clinical centers. The participants received either DSC or placebo for 4 weeks. The primary efficacy measure was headache-free rate (HFR) in a 4-week period between the pretreatment and posttreatment stages. The secondary efficacy measures were the decrease of headache days, the duration of headache attacks, the frequency of analgesic usage, quality of life, disability, and the headache severity (VAS scores). The accompanying symptoms and adverse events were also assessed. Results. Of 584 CDH patients assessed, 468 eligible patients were randomized. 338 patients received DSC, while 111 patients were assigned in the placebo group. Following treatment, there was a 16.56% difference in HFR favoring DSC over placebo (P<0.01). Significant differences were also observed between DSC and placebo groups in the secondary measures. However, no statistical difference was found between the two groups in the associated symptoms. No severe adverse effects were observed in the study. Conclusions. DSC might be an effective and well-tolerated option for the prophylactic treatment of patients with CDH

Additional file 1 of A phase 3, randomised, placebo-controlled study of erenumab for the prevention of chronic migraine in patients from Asia: the DRAGON study

Additional file 1: Supplementary Table 1. Definitions used in the study. Supplementary Table 2. Details of eligibility criteria. Supplementary Table 3. Patient reported outcome tool: mMIDAS. Supplementary Table 4. Change from baseline in MMD by visit, observed,mixed model repeated measures (full analysis set). Supplementary Table 5. Patientincidence rates of treatment-emergent SAEs in the study by primary SOC (Safety analysis set)

A direct Z-scheme g-C3N4/SnS2 photocatalyst with superior visible-light CO2 reduction performance

Highlights - SnS2 quantum dots anchored in situ on g-C3N4 by a simple one-step hydrothermal method. - The internal electric field between g-C3N4 and SnS2 was confirmed. - Internal-electric-field-induced direct Z-scheme g-C3N4/SnS2 charge transfer for enhanced photocatalytic CO2 reduction. - In situ FTIR analysis further proved the suggested photocatalytic mechanism. Abstract Photocatalytic reduction of CO2 to solar fuels is an ideal approach to simultaneously solve the global warming and energy crisis issues. Constructing a direct Z-scheme heterojunction is an effective way to overcome the drawbacks of single-component or conventional heterogeneous photocatalysts for photocatalytic CO2 reduction. Here, a novel type of direct Z-scheme g-C3N4/SnS2 heterojunction was constructed by depositing SnS2 quantum dots onto the g-C3N4 surface in situ via a simple one-step hydrothermal method. l-Cysteine not only acted as the sulfur source, but also grafted ammine groups onto g-C3N4 in the hydrothermal process, which greatly enhanced the CO2 uptake of the composite. XPS analysis and density functional theory (DFT) calculation show that electron transfer occurred from g-C3N4 to SnS2, resulting in the formation of interfacial internal electric fields (IEF) between the two semiconductors at equilibrium. As a result, Z-scheme charge transfer took place under photoexcitation, with the electrons in SnS2 combining with the holes in g-C3N4, which improved the extraction and utilization of photoinduced electron in g-C3N4. The g-C3N4/SnS2 hybrid shows superior photocatalytic CO2 reduction as compared with individual g-C3N4 and SnS2, which should be attributed to the IEF-induced direct Z-scheme as well as improved CO2 adsorption capacity. In situ FTIR spectra illustrate that HCOOH appeared as an intermediate during the CO2 conversion, which can only be generated by g-C3N4 according to the energy level of the photoinduced electrons, further confirming the Z-scheme configuration for the g-C3N4/SnS2 system

Status of diagnosis and preventative treatment for primary headache disorders: real-world data of unmet needs in China

Abstract Background Headache disorders are widely prevalent and pose a considerable economic burden on individuals and society. Globally, misdiagnosis and inadequate treatment of primary headache disorders remain significant challenges, impeding the effective management of such conditions. Despite advancements in headache management over the last decade, a need for comprehensive evaluations of the status of primary headache disorders in China regarding diagnosis and preventative treatments persists. Methods In the present study, we analyzed the established queries in the Survey of Fibromyalgia Comorbidity with Headache (SEARCH), focusing on previous diagnoses and preventative treatment regimens for primary headache disorders. This cross-sectional study encompassed adults diagnosed with primary headache disorders who sought treatment at 23 hospitals across China between September 2020 to May 2021. Results The study comprised 2,868 participants who were systematically examined. Migraine and tension-type headaches (TTH) constituted a majority of the primary headache disorders, accounting for 74.1% (2,124/2,868) and 23.3% (668/2,868) of the participants, respectively. Medication overuse headache (MOH) affected 8.1% (231/2,868) of individuals with primary headache disorders. Over half of the individuals with primary headache disorders (56.6%, 1,624/2,868) remained undiagnosed. The previously correct diagnosis rates for migraine, TTH, TACs, and MOH were 27.3% (580/2,124), 8.1% (54/668), 23.2% (13/56), and 3.5% (8/231), respectively. The misdiagnosis of “Nervous headache” was found to be the most prevalent among individuals with migraine (9.9%, 211/2,124), TTH (10.0%, 67/668), trigeminal autonomic cephalalgias (TACs) (17.9%, 10/56), and other primary headache disorders (10.0%, 2/20) respectively. Only a minor proportion of individuals with migraine (16.5%, 77/468) and TTH (4.7%, 2/43) had received preventive medication before participating in the study. Conclusions While there has been progress made in the rate of correct diagnosis of primary headache disorders in China compared to a decade ago, the prevalence of misdiagnosis and inadequate treatment of primary headaches remains a veritable issue. As such, focused efforts are essential to augment the diagnosis and preventive treatment measures related to primary headache disorders in the future