Optimized Design, Monitoring System Development and Experiment for a Long-Belt Finger-Clip Precision Corn Seed Metering Device

To solve multiple problems, such as the poor seeding process stability in the conventional finger-clip precision corn seed metering device and the inability to monitor the seeding effect, a long-belt finger-clip precision seed metering device was optimized and designed. The overall structure and working principle were described, and the mechanism of smooth transport and delivery was analyzed. A diffuse reflection photoelectric sensor and rectangular optical fiber sensor were used to monitor the number of corn seeds in the seeding process, and the states of multiple and miss seeding were calculated. A corn seeding quality monitoring system was designed. In this study, the seed metering performance of the long-belt finger-clip precision seed metering device was compared to that of the conventional finger-clip precision corn seed metering device. It was shown that the reseeding index, the miss-seeding index and the coefficient of variation can be effectively reduced with increasing seed metering tray speed. At the maximum speed of 65r/min, the qualified index increased from 75.75 to 84.70%, the reseeding index decreased from 13.66 to 8.49%, the miss-seeding index decreased from 10.59 to 6.81%, and the coefficient of variation decreased from 20.69 to 6.83%. The variations of these four evaluation parameters with the seed metering tray rotating speed were analyzed. Furthermore, the effects of the seeding frequency and seeding speed on the four evaluation parameters were studied through single factor and variance analyses. The results showed that the relative errors of the qualified index, the reseeding index, the miss-seeding index and the seeding amount increased gradually with the increase in the seed metering tray rotating speed, and the monitoring accuracy of the sensor decreased gradually. The accuracy of sensor monitoring decreased with increasing seeding frequency and seeding speed. This study provides an optimized scheme for the smooth delivery and movement of conventional seed metering devices and provides a technical reference for the development and design of monitoring systems with multiple index and the miss-seeding index of seed metering devices.

Evolutionary history of the oriental fire-bellied toad (Bombina orientalis) in Northeast China

The evolutionary history of a species is generally affected by the combination of geological events and climate fluctuations. By analyzing the population features, genetic structure and the effective population historical dynamics of existing species, the population evolutionary history can be reestablished. In recent years, geological evidence shows that the Yilan-Yitong fault zone located in Northeast Asia experienced strong and frequent geological changes in the late Quaternary period. Species population history has been shaped by the combination of the complex climatic conditions of the Quaternary and Pleistocene glacial interglacial cycles and palaeogeological events in Northeast Asia and it has become a research focus for evolutionary biology researchers. In this study, mitochondrial and microsatellite molecular markers were used to reveal the population features, genetic structure, and the effective population historical dynamics of the Oriental fire-bellied toad (Bombina orientalis). The results showed that the strong seismic activity of the Yilan-Yitong fault zone in the late Quaternary period was the main reason for the population differentiation of Oriental fire-bellied toad in northeast China. The Quaternary Pleistocene glacial interglacial cycles led to the significant bottleneck effect of the western population located in the Maoer mountain area. As a result, the western population has low genetic diversity. Recent gene flow between eastern and western populations and historical evidence of population expansion proved that the dispersal behavior of the western populations was the main cause of the low genetic diversity and mitochondrial and nuclear discordance. Human economic activity may be the mainly driving factor. These evidences showed that the comprehensive influence of geology, climate, human activities and other factors should be considered in the process of exploring the evolutionary history of species.

Insights into Synergistic Effect of Acid on Morphological Control of Vanadium Oxide: Toward High Lithium Storage

Morphological control is a fundamental challenge of nanomaterial development. Commonly, hierarchical nanostructures cannot be induced by a single driving force, but obtained through balancing multiple driving forces. Here, a feasible strategy is reported based on the synergistic effect of proton and acid anion, leading to the morphological variation of vanadium oxide from nanowire, bundle, to hierarchical nanoflower (HNF). Protons can only induce the formation of nanowire through reducing the pH value ≤ 2. However, acid anions with strong coordination ability, e.g., phosphate radicals, can also participate in morphological regulation at high concentration. Through coordinating with exposed vanadium ions, the enrichment of phosphate radicals at ledge and kink changes the growth directions, giving rise to the advanced structures of bundle and HNF. The lithium ion batteries using HNF as a cathode achieve a 30% improved initial discharge specific capacity of 436.23 mAh g-1 at a current density of 0.1 A g-1, reaching the theoretical maximum value of vanadium oxide based on insertion/desertion of three lithium ions, in addition to strong cyclic stability at 1 A g-1.

AtNSF regulates leaf serration by modulating intracellular trafficking of PIN1 in Arabidopsis thaliana

In eukaryotes, N-ethylmaleimide-sensitive factor (NSF) is a conserved AAA+ ATPase and a key component of the membrane trafficking machinery that promotes the fusion of secretory vesicles with target membranes. Here, we demonstrate that the Arabidopsis thaliana genome contains a single copy of NSF, AtNSF, which plays an essential role in the regulation of leaf serration. The AtNSF knock-down mutant, atnsf-1, exhibited more serrations in the leaf margin. Moreover, polar localization of the PIN-FORMED1 (PIN1) auxin efflux transporter was diffuse around the margins of atnsf-1 leaves and root growth was inhibited in the atnsf-1 mutant. More PIN1-GFP accumulated in the intracellular compartments of atnsf-1 plants, suggesting that AtNSF is required for intracellular trafficking of PIN between the endosome and plasma membrane. Furthermore, the serration phenotype was suppressed in the atnsf-1 pin1-8 double mutant, suggesting that AtNSF is required for PIN1-mediated polar auxin transport to regulate leaf serration. The CUP-SHAPED COTYLEDON2 (CUC2) transcription factor gene is up-regulated in atnsf-1 plants and the cuc2-3 single mutant exhibits smooth leaf margins, demonstrating that AtNSF also functions in the CUC2 pathway. Our results reveal that AtNSF regulates the PIN1-generated auxin maxima with a CUC2-mediated feedback loop to control leaf serration. This article is protected by copyright. All rights reserved.

Dual-Enhanced Doping in ReSe2 for Efficiently Photoenhanced Hydrogen Evolution Reaction

Rhenium dichalcogenides (ReX2, X = S or Se) are catalysts that have great promise for the photoenhanced hydrogen evolution reaction (PE-HER) because of their unique physiochemical properties. However, the catalytic performance is still restricted by their low concentration of electrocatalytic activity sites and poor injection of hot electrons. Herein, dual-enhancement in ReSe2 nanosheets (NSs) with high concentration of active sites and efficient use of hot electrons is simultaneously achieved with moderate Mo doping. Contributions from exposed catalytically active sites, improved electrical conductivity, and enhanced solar spectral response are systematically investigated. Superior PE-HER catalytical performance is obtained in Re0.94Mo0.06Se2, which has more catalytically active sites and optimized band structure than other Re1- x Mo x Se2 samples. Here, it is demonstrated that only doping can reduce the overpotential (η10) from 239 to 174 mV at -10 mA cm-2 (Δ1η10 = 65 mV). Then, η10 is further improved to 137 mV under simulated AM 1.5 sun illumination (Δ2η10 = 37 mV). The total improvement (Δη10) toward PE-HER is 102 mV (Δ1η10 + Δ2η10 = 102 mV) in optimal Re0.94Mo0.06Se2. This work presents a new perspective for researching high-efficiency photoenhanced HER ReSe2-based electrocatalysts and other layered transition metal dichalcogenides.

piRNA-63076 contributes to pulmonary arterial smooth muscle cell proliferation through acyl-CoA dehydrogenase

Piwi-interacting RNAs (piRNAs) are thought to be germline-specific and to be involved in maintaining genome stability during development. Recently, piRNA expression has been identified in somatic cells in diverse organisms. However, the roles of piRNAs in pulmonary arterial smooth muscle cell (PASMC) proliferation and the molecular mechanism underlying the hypoxia-regulated pathological process of pulmonary hypertension are not well understood. Using hypoxic animal models, cell and molecular biology, we obtained the first evidence that the expression of piRNA-63076 was up-regulated in hypoxia and was positively correlated with cell proliferation. Subsequently, we showed that acyl-CoA dehydrogenase (Acadm), which is negatively regulated by piRNA-63076 and interacts with Piwi proteins, was involved in hypoxic PASMC proliferation. Finally, Acadm inhibition under hypoxia was partly attributed to DNA methylation of the Acadm promoter region mediated by piRNA-63076. Overall, these findings represent invaluable resources for better understanding the role of epigenetics in pulmonary hypertension associated with piRNAs.

The optimization of fermentation conditions for Pichia pastoris GS115 producing recombinant xylanase

Xylanase is a member of an important family of enzymes that has been used in many biotechnological processes. However, the overall cost of enzyme production has been the main problem in the industrial application of enzymes. To obtain maximum xylanase production, statistical approaches based on the Plackett-Burman design and response surface methodology were employed. The results of the statistical analyses demonstrated that the optimal conditions for increased xylanase production were the following: inoculum size, 3.8%; maize meal, 4.5%; histidine, 0.6%; methanol, 1%; culture volume, 20%; bean pulp, 30 g L-1; and Tween-80, 0.8%; and pH 5.0. Verification of the optimization demonstrated that 3273 U mL-1 xylanase was observed under the optimal conditions in shake flask experiments. SDS-PAGE results showed that the size of xylanase protein was about 23 kDa. The results showed that the xylanase produced by fermentation came from Aspergillus Niger by MALDI-TOF-MS. The optimized medium resulted in 2.1- and 1.4-fold higher the activity of xylanase compared with the unoptimized medium (the main nutrients are maize meal and bean pulp) and laboratory medium (the main nutrients are yeast extract and peptone), respectively. The optimization of fermentation conditions is an effective means to reduce production cost and improve xylanase activity.

Phagocytosis by endothelial cells inhibits procoagulant activity of platelets of essential thrombocythemia in vitro

BACKGROUND

Essential thrombocythemia (ET) is characterized by thrombocytosis with increased platelet number and persistent activation. The mechanisms of thrombosis and the fate of these platelets are not clear. The aim of the present study is to explore the phagocytosis of platelets of ET patients by endothelial cells (ECs) in vitro and its relevance to the procoagulant activity (PCA).

METHODS

Phosphatidylserine (PS) exposure on platelets was detected by flow cytometry. Phagocytosis of the platelets by ECs was performed using flow cytometry, confocal microscopy, and electron microscopy. The PCA of platelets was evaluated by coagulation time and purified coagulation complex assays.

RESULTS

The PS exposure on platelets in ET patients is higher than that in healthy controls. The PS-exposed platelets are highly procoagulant and lactadherin reduced 80% of the PCA by blockade of PS. When cocultured, the platelets of ET patients were sequestered by ECs in a time-dependent fashion. Lactadherin enhanced phagocytosis by bridging the PS on activated platelets and the integrin αvβ3 on ECs, and P-selectin played at least a partial role in this process. Furthermore, factor Xa and prothrombinase activity of PS-exposed platelets were decreased after incubation with ECs.

CONCLUSION

Our results suggest that phagocytic clearance of platelets by ECs occurs in ET patients, thus representing a novel mechanism to remove activated platelets from the circulation; lactadherin and phagocytosis could cooperatively limit the thrombophilia in ET patients.