MODAL RESPONSE AND VIBRATION CHARACTERISTICS OF SUGAR BEET COMBINE HARVESTER FRAME

ABSTRACT In complex environments, beet harvesters vibrate strongly under the influence of multiple sources of excitation. The modal constraints of the harvester's frame were obtained using modal simulation, and the accuracy of the finite element model was verified through SIMO modal testing. Additionally, field experiments were conducted to collect the vibration signals of the harvester under various conditions. Time-domain analysis revealed that the RMS value of the frame's Z-axis acceleration was highest in sugar beet fields and lowest on unpaved roads. There is a correlation between the operation of working components and changes in amplitude. Frequency domain analysis determined that the main vibration frequency of the frame was in the range of 0–75 Hz, and the operating frequency of the engine (35 Hz) and the power input shaft (12.7 Hz) excites the constrained modal of the frame, which may lead to resonance. Integrating the results of the modal response and vibration testing provides a more comprehensive approach to studying the vibration characteristics of agricultural machinery

DESIGN AND DISCRETE ELEMENT SIMULATION OF A BIOMIMETIC WEEDING DEVICE MODELLED ON A CRAB CLAW TOE

ABSTRACT As weeds cannot be eradicated in corn fields, a crab claw toe was used as the research object and combined with the agronomic requirements of corn fields to design a bionic weed claw suitable for corn fields. The contour curve of the crab claw toe was extracted and fitted through the Matlab image processing technology and fitting tool to establish a bionic claw finger 3D model using Solid works. According to the mechanical soil dynamics theory of dynamics analysis, the root–soil aggregates are easily broken, loosened, and drained under the action of the bionic claw fingers. Based on single image inverse reconstruction technology, the weed root system–soil aggregates discrete meta-model was established. Recur Dyn was used in the bionic weed claw kinematics simulation to verify the reliability of the movement of the mechanism and to realise the expected action of the weeding operation. We analysed the movement speed, displacement, and trajectory of soil particles in different depth layers through the joint simulation and comparison test. Using the mechanism of weeding and resistance reduction of the bionic weeding claw, under the same working conditions, the average resistance reduction rate of the bionic claw finger compared with the flat claw finger in the grasping process was 16.4%. The resistance of grass roots was reduced 23.3%, making it easier to pull out the more intact grass roots

Malondialdehyde Suppresses Cerebral Function by Breaking Homeostasis between Excitation and Inhibition in Turtle Trachemys scripta

The levels of malondialdehyde (MDA) are high in the brain during carbonyl stress, such as following daily activities and sleep deprivation. To examine our hypothesis that MDA is one of the major substances in the brain leading to fatigue, the influences of MDA on brain functions and neuronal encodings in red-eared turtle (Trachemys scripta) were studied. The intrathecal injections of MDA brought about sleep-like EEG and fatigue-like behaviors in a dose-dependent manner. These changes were found associated with the deterioration of encoding action potentials in cortical neurons. In addition, MDA increased the ratio of γ-aminobutyric acid to glutamate in turtle's brain, as well as the sensitivity of GABAergic neurons to inputs compared to excitatory neurons. Therefore, MDA, as a metabolic product in the brain, may weaken cerebral function during carbonyl stress through breaking the homeostasis between excitatory and inhibitory neurons

Determination of conifer age biomarker DAL1 interactome using Y2H-seq

Age is a sophisticated physiological signal that ensures the sequence of different developmental stages in organisms. The regulation of ageing pathways appears to differ between gymnosperms and angiosperms. We previously identified DAL1 as a conserved conifer age biomarker that plays a crucial role in the transition from vegetative to reproductive life-history phases in pines. Therefore, elucidating the specific interaction events related to DAL1 is key to understanding how age drives conifer development. Large-scale yeast two-hybrid (Y2H) analysis followed by next-generation high-throughput sequencing (Y2H-seq) allowed us to identify 135 PtDAL1 interacting proteins in Pinus tabuliformis. Our study found that PtDAL1 interacting proteins showed an ageing-related module, with sophisticated interacting networks composed of transcription factors (TFs), transcriptional regulators (TRs), and kinases. These interacting proteins are produced in response to a variety of phytohormones and environmental signals, and are likely involved in wood formation, needle development, oleoresin terpenoids biosynthesis, and reproductive development. In this study, we propose a novel regulation model of conifer ageing pathways whereby PtDAL1 coordinates different environmental stimuli and interacts with corresponding proteins to regulate appropriate development

What contributes to medical debt? Evidence from patients in rural China.

BACKGROUND: Rural households in developing countries usually have severe medical debt due to high out-of-pocket (OOP) payments, which contributes to bankruptcy. China implemented the critical illness insurance (CII) in 2012 to decrease patients' medical expenditure. This paper aimed to explore the medical debt of rural Chinese patients and its influencing factors. METHODS: A questionnaire survey of health expenditures and medical debt was conducted in two counties of Central and Western China in 2017. Patients who received CII were used as the sample on the basis of multi-stage stratified cluster sampling. Descriptive statistics and multivariate analysis of variance were used in all data. A two-part model was used to evaluate the occurrence and extent of medical debt. RESULTS: A total of 826 rural patients with CII were surveyed. The percentages of patients incurring medical debt exceeded 50% and the median debt load was 20,000 Chinese yuan (CNY, 650 CNY = US$100). Financial assistance from kin (P < 0.001) decreased the likelihood of medical debt. High inpatient expenses (IEs, P < 0.01), CII reimbursement ratio (P < 0.001), and non-direct medical costs (P < 0.001) resulted in increased medical debt load. CONCLUSIONS: Medical debt is still one of the biggest problems in rural China. High IEs, CII reimbursement ratio, municipal or high-level hospitals were the risk determinants of medical debt load. Financial assistance from kin and household income were the protective factors. Increasing service capability of hospitals in counties could leave more patiemts in county-level and township hospitals. Improving CII with increased reimbursement rate may also be issues of concern

A 5-50 Gb/s quarter rate transmitter with a 4-tap multiple-MUX based FFE in 65 nm CMOS

This paper presents a 5-50 Gb/s quarter-rate transmitter with a 4-tap feed-forward equalization (FFE) based on multiple-multiplexer (MUX). A bandwidth enhanced 4:1 MUX with the capability of eliminating charge-sharing effect is proposed to increase the maximum operating speed. To produce the quarter-rate parallel data streams with appropriate delays, a compact latch array associated with an interleaved-retiming technique is designed. Implemented in 65 nm CMOS technology, the transmitter occupying an area of 0.6 mm2 achieves a maximum data rate of 50 Gb/s with an energy efficiency of 3.1 pJ/bit

Rapid and Visual Detection of Monkey B Virus Based on Recombinase Polymerase Amplification

Monkey B virus (BV) infection in humans and other macaque species has a mortality rate of approximately 80%. Because BV infects humans through bites, scratches, and other injuries inflicted by macaques, the simple and rapid diagnosis of BV in field laboratories is of great importance to protect veterinarians, laboratory researchers, and support personnels from the threat of infection. Two recombinase polymerase amplification (RPA) assays with a closed vertical flow (VF) visualization strip (RPA-VF-UL27 and RPA-VF-US6) were developed that target two conserved genes combined with a one-off, closed visualization strip device. We compared the sensitivities and specificities of the two assays after optimization of the reaction conditions. The performance of RPA-VF-US6 at room temperature was determined to evaluate its potential in point-of-care (POC) testing. RPA-VF-US6 specifically detected the positive plasmid control (rather than nucleic acids of herpesviruses) with a detection limit of 28 copies, while RPA-VF-UL27 had cross-reactivity with HSV-1, but even 3.4 copies of plasmid standards were readout by this assay. Moreover, RPA-VF-US6 had excellent performance at room temperature (the detection limit was 2,800 plasmid copies), indicating the potential of RPA-VF-US6 in POC testing. We developed two RPA assays for BV visualization diagnosis. RPA-VF-US6 is a simple, rapid, and specific detection method for BV. The entire reaction can be performed at a constant temperature within 30 min, suggesting the potential of RPA-VF-US6 for POC testing in field laboratories without sophisticated instruments

The Chinese pine genome and methylome unveil key features of conifer evolution

Conifers dominate the world's forest ecosystems and are the most widely planted tree species. Their giant and complex genomes present great challenges for assembling a complete reference genome for evolutionary and genomic studies. We present a 25.4-Gb chromosome-level assembly of Chinese pine (Pinus tabuliformis) and revealed that its genome size is mostly attributable to huge intergenic regions and long introns with high transposable element (TE) content. Large genes with long introns exhibited higher expressions levels. Despite a lack of recent whole-genome duplication, 91.2% of genes were duplicated through dispersed duplication, and expanded gene families are mainly related to stress responses, which may underpin conifers' adaptation, particularly in cold and/or arid conditions. The reproductive regulation network is distinct compared with angiosperms. Slow removal of TEs with high-level methylation may have contributed to genomic expansion. This study provides insights into conifer evolution and resources for advancing research on conifer adaptation and development

The methylation landscape of giga-genome and the epigenetic timer of age in Chinese pine

DNA methylation level declines during aging of mammals. Here, the authors report single-base resolution landscape of cytosine DNA methylation at different ages of Chinese pine and show that the global cytosine DNA methylation gradually increases as age progresses.Epigenetics has been revealed to play a crucial role in the long-term memory in plants. However, little is known about whether the epigenetic modifications occur with age progressively in conifers. Here, we present the single-base resolution DNA methylation landscapes of the 25-gigabase Chinese pine (Pinus tabuliformis) genome at different ages. The result shows that DNA methylation is closely coupled with the regulation of gene transcription. The age-dependent methylation profile with a linearly increasing trend is the most significant pattern of DMRs between ages. Two segments at the five-prime end of the first ultra-long intron in DAL1, a conservative age biomarker in conifers, shows a gradual decline of CHG methylation as the age increased, which is highly correlated with its expression profile. Similar high correlation is also observed in nine other age marker genes. Our results suggest that DNA methylation serves as an important epigenetic signature of developmental age in conifers