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Abstract The aryl hydrocarbon receptor (AHR) possesses an extraordinary capacity to sense and respond to a wide range of small-molecule ligands, ranging from polycyclic aromatic hydrocarbons to endogenous compounds. Upon ligand binding, AHR translocates from the cytoplasm to nucleus, forming a transcriptionally active complex with aryl hydrocarbon receptor nuclear translocator (ARNT), for DNA binding and initiation of gene expression programs that include cellular detoxification pathways and immune responses. Here, we examine the molecular mechanisms governing AHR’s high-affinity binding and activation by a diverse group of ligands. Crystal structures of the AHR-ARNT-DNA complexes, bound with each of six established AHR ligands, including Tapinarof, 6-formylindolo[3,2-b]carbazole (FICZ), benzo[a]pyrene (BaP), β-naphthoflavone (BNF), Indigo and Indirubin, reveal an unconventional mode of subunit assembly with intimate association between the PAS-B domains of AHR and ARNT. AHR’s PAS-B domain utilizes eight conserved residues whose dynamic rearrangements account for the ability to bind to ligands through hydrophobic and π-π interactions. Our findings further reveal the structural underpinnings of a ligand-driven activation mechanism, whereby a segment of the AHR protein undergoes a structural transition from chaperone engagement to ARNT heterodimer stabilization, to generate the transcriptionally competent assembly. Our results provide key information for the future development of AHR-targeting drugs.

Heat waves are a significant environmental issue threatening global human health. Extreme temperatures can lead to various heat-related illnesses, with heatstroke being among the most severe. Currently, there are no effective treatments to mitigate the multi-organ damage caused by heatstroke. We found that heat stress activated autophagy. Knockdown of the autophagy-related gene 7 (ATG7) or knockout of the autophagy initiation regulatory genes UNC-51-like autophagy activating kinase 1/2 (ULK1/ULK2) increased cell death. PF-06409577, an allosteric activator of AMP-activated protein kinase β (AMPKβ), reduced heat stress-induced cell death by promoting autophagy. Inhibition of ATG7 or ULK1 weakened PF-06409577′s protective effect on cells. Treatment of heatstroke mouse models with PF-06409577 suppressed high temperature-induced damage to multiple organs, including the liver, kidneys, lungs, and small intestine. PF-06409577 protected liver and kidney functions, lowered the expression of kidney injury markers neutrophil gelatinase associated lipocalin (Ngal), secreted phosphoprotein 1 (Spp1), and clusterin (Clu), and reduced levels of the inflammatory factor IL-6. Additionally, it decreased heat stress-induced macrophage infiltration and IL-6 production in the liver. The results indicate that activation of autophagy serves a protective function during heat stress, and the AMPK activator PF-06409577 exhibits potential in mitigating heatstroke-induced multi-organ damage through its ability to promote autophagy.

Abstract Background Abnormal amyloid β (Aβ) deposits in the brain are a hallmark of Alzheimer’s disease (AD). Insufficient sleep duration and poor sleep quality are risk factors for developing AD. Sleep may play a role in Aβ regulation, but the magnitude of the relationship between sleep and Aβ deposition remains unclear. This systematic review examines the relationship between sleep (i.e., duration and efficiency) with Aβ deposition in later-life adults. Methods A search of PubMed, CINAHL, Embase, and PsycINFO generated 5,005 published articles. Fifteen studies met the inclusion criteria for qualitative syntheses; thirteen studies for quantitative syntheses related to sleep duration and Aβ; and nine studies for quantitative syntheses related to sleep efficiency and Aβ. Results Mean ages of the samples ranged from 63 to 76 years. Studies measured Aβ using cerebrospinal fluid, serum, and positron emission tomography scans with two tracers: Carbone 11-labeled Pittsburgh compound B or fluorine 18-labeled. Sleep duration was measured subjectively using interviews or questionnaires, or objectively using polysomnography or actigraphy. Study analyses accounted for demographic and lifestyle factors. Based on 13 eligible articles, our synthesis demonstrated that the average association between sleep duration and Aβ was not statistically significant (Fisher’s Z = -0.055, 95% CI = -0.117 ~ 0.008). We found that longer self-report sleep duration is associated with lower Aβ (Fisher’s Z = -0.062, 95% CI = -0.119 ~ -0.005), whereas the objectively measured sleep duration was not associated with Aβ (Fisher’s Z = 0.002, 95% CI = -0.108 ~ 0.113). Based on 9 eligible articles for sleep efficiency, our synthesis also demonstrated that the average association between sleep efficiency and Aβ was not statistically significant (Fisher’s Z = 0.048, 95% CI = -0.066 ~ 0.161). Conclusion The findings from this review suggest that shorter self-reported sleep duration is associated with higher Aβ levels. Given the heterogeneous nature of the sleep measures and outcomes, it is still difficult to determine the exact relationship between sleep and Aβ. Future studies with larger sample sizes should focus on comprehensive sleep characteristics and use longitudinal designs to better understand the relationship between sleep and AD.

Abstract Background Neddylation, an important post-translational modification (PTM) of proteins, plays a crucial role in follicular development. MLN4924 is a small-molecule inhibitor of the neddylation-activating enzyme (NAE) that regulates various biological processes. However, the regulatory mechanisms of neddylation in rabbit ovarian cells have not been emphasized. Here, the transcriptome and metabolome profiles in granulosa cells (GCs) treated with MLN4924 were utilized to identify differentially expressed genes, followed by pathway analysis to precisely define the altered metabolisms. Results The results showed that 563 upregulated and 910 downregulated differentially expressed genes (DEGs) were mainly enriched in pathways related to cancer, cell cycle, PI3K-AKT, progesterone-mediated oocyte maturation, and PPAR signaling pathway. Furthermore, we characterized that MLN4924 inhibits PPAR-mediated lipid metabolism, and disrupts the cell cycle by promoting the apoptosis and proliferation of GCs. Importantly, we found the reduction of several metabolites in the MLN4924 treated GCs, including glycerophosphocholine, arachidic acid, and palmitic acid, which was consistent with the deregulation of PPAR signaling pathways. Furthermore, the increased metabolites included 6-Deoxy-6-sulfo-D-glucono-1,5-lactone and N-Acetyl-D-glucosaminyldiphosphodolichol. Combined with transcriptome data analyses, we identified genes that strongly correlate with metabolic dysregulation, particularly those related to glucose and lipid metabolism. Therefore, neddylation inhibition may disrupt the energy metabolism of GCs. Conclusions These results provide a foundation for in-depth research into the role and molecular mechanism of neddylation in ovary development.

Plant-based fermentations provide an untapped source for novel biotechnological applications. In this study, a probiotic named Lactobacillus fermentum 21828 was introduced to ferment Lentinus edodes. Polysaccharides were extracted from fermented and non-fermented L. edodes and purified via DEAE-52 and Sephadex G-100. The components designated F-LEP-2a and NF-LEP-2a were analyzed by FT-IR, HPGPC, HPAEC, SEM, GC-MS and NMR. The results revealed that probiotic fermentation increased the molecular weight from 1.16 × 104 Da to 1.87 × 104 Da and altered the proportions of glucose, galactose and mannose, in which glucose increased from 45.94 % to 48.16 %. Methylation analysis and NMR spectra indicated that F-LEP-2a and NF-LEP-2a had similar linkage patterns. Furthermore, their immunomodulatory activities were evaluated with immunosuppressive mice. NF-LEP and F-LEP improved immune organ indices, immunoglobulin (IgG and IgM) and cytokines concentrations; restored the antioxidation capacity of liver; and maintained the balance of gut microbiota. F-LEP displayed better moderating effects on the spleen index, immunoglobulin, cytokines and the diversity of gut microbiota than NF-LEP (200, 400 mg/kg). Our study provides an efficient and environment-friendly way for the structural modification of polysaccharides, which helps to enhance their biological activity and promote their wide application in food, medicine and other fields.

Whether hypoxia-inducible factors (HIFs) can be directly regulated by endogenous small molecules is a long-standing question. Here authors identified the metabolite oleoylethanolamide as a HIF-3α ligand and further revealed its mechanism of action.

BackgroundA wide range of bacterial pathogens have been identified in ticks, yet the diversity of viruses in ticks is largely unexplored.MethodsHere, we used metagenomic sequencing to characterize the diverse viromes in three principal tick species associated with pathogens, Haemaphysalis concinna, Dermacentor silvarum, and Ixodes persulcatus, in North China.ResultsA total of 28 RNA viruses were identified and belonged to more than 12 viral families, including single-stranded positive-sense RNA viruses (Flaviviridae, Picornaviridae, Luteoviridae, Solemoviridae, and Tetraviridae), negative-sense RNA viruses (Mononegavirales, Bunyavirales, and others) and double-stranded RNA viruses (Totiviridae and Partitiviridae). Of these, Dermacentor pestivirus-likevirus, Chimay-like rhabdovirus, taiga tick nigecruvirus, and Mukawa virus are presented as novel viral species, while Nuomin virus, Scapularis ixovirus, Sara tick-borne phlebovirus, Tacheng uukuvirus, and Beiji orthonairovirus had been established as human pathogens with undetermined natural circulation and pathogenicity. Other viruses include Norway mononegavirus 1, Jilin partitivirus, tick-borne tetravirus, Pico-like virus, Luteo-like virus 2, Luteo-likevirus 3, Vovk virus, Levivirus, Toti-like virus, and Solemo-like virus as well as others with unknown pathogenicity to humans and wild animals.ConclusionIn conclusion, extensive virus diversity frequently occurs in Mononegavirales and Bunyavirales among the three tick species. Comparatively, I. persulcatus ticks had been demonstrated as such a kind of host with a significantly higher diversity of viral species than those of H. concinna and D. silvarum ticks. Our analysis supported that ticks are reservoirs for a wide range of viruses and suggested that the discovery and characterization of tick-borne viruses would have implications for viral taxonomy and provide insights into tick-transmitted viral zoonotic diseases.

In this study, we screened the expression stability of six reference genes (18S rRNA, β-actin, GAPDH, EF1a, B2M, and HPRT1) in hybrid yellow catfish (n = 6), considering the SBM levels, sampling time points, and different tissues. Four different statistical programs, BestKeeper, NormFinder, Genorm, and Delta Ct, combined with a method that comprehensively considered all results, were used to evaluate the expression stability of these reference genes systematically. The results showed that SBM levels significantly impacted the expression stability of most of the reference genes studied and that this impact was time-, dose-, and tissue-dependent. The expression stability of these six reference genes varied depending on tissue, sampling time point, and SBM dosage. Additionally, more variations were found among different tissues than among different SBM levels or sampling time points. Due to its high expression, 18S rRNA was excluded from the list of candidate reference genes. β-actin and GAPDH in the liver and β-actin, HPRT1 and EF1a in the intestine were the most stable reference genes when SBM levels were considered. HPRT1, and EF1a in tissues sampled at 2 W and EF1a and β-actin in tissues sampled at 4 and 6 W were proposed as two stable reference genes when different tissues were considered. When the sampling time points were considered, β-actin, EF1a, and HPRT1 were the top three stable reference genes in the intestine. In contrast, β-actin and B2M are the most stable reference genes in the liver. In summary, β-actin, EF1a, and HPRT1 were the more stable reference genes in this study. The stability of reference genes depends on the tissues, sampling time points, and SBM diet levels in hybrid yellow catfish. Therefore, attention should be paid to these factors before selecting suitable reference genes for normalizing the target genes.

The application of mobile robots is an important link in the development of intelligent greenhouses. In view of the complex environment of a greenhouse, achieving precise positioning and navigation by robots has become the primary problem to be solved. Simultaneous localization and mapping (SLAM) technology is a hot spot in solving the positioning and navigation in an unknown indoor environment in recent years. Among them, the SLAM based on a two-dimensional (2D) Lidar can only collect the environmental information at the level of Lidar, while the SLAM based on a 3D Lidar demands a high computation cost; hence, it has higher requirements for the industrial computers. In this study, the robot navigation control system initially filtered the information of a 3D greenhouse environment collected by a 3D Lidar and fused the information into 2D information, and then, based on the robot odometers and inertial measurement unit information, the system has achieved a timely positioning and construction of the greenhouse environment by a robot using a 2D Lidar SLAM algorithm in Cartographer. This method not only ensures the accuracy of a greenhouse environmental map but also reduces the performance requirements on the industrial computer. In terms of path planning, the Dijkstra algorithm was used to plan the global navigation path of the robot while the Dynamic Window Approach (DWA) algorithm was used to plan the local navigation path of the robot. Through the positioning test, the average position deviation of the robot from the target positioning point is less than 8 cm with a standard deviation (SD) of less than 3 cm; the average course deviation is less than 3° with an SD of less than 1° at the moving speed of 0.4 m/s. The robot moves at the speed of 0.2, 0.4, and 0.6 m/s, respectively; the average lateral deviation between the actual movement path and the target movement path is less than 10 cm, and the SD is less than 6 cm; the average course deviation is

Fibrous materials have unique applications in drug release and biomedical fields. This study reports on the preparation of porous silica nanofibers, using organic nanofibers as templates, and their use for drug release. Different from the commonly used electrospinning method, the organic nanofibers are produced via a self-assembly approach between melamine and benzene-1,3,5-tricarboxylic acid. Silica is then coated on the organic nanofibers via homogenization in a silica sol, a freeze-drying process, and then a sol–gel process. In order to regulate the surface area and mesopore volume of silica nanofibers, cetyltrimethyl ammonium bromide at different concentrations is used as template in the sol–gel process. With the removal of organic nanofibers and the surfactant by calcination, porous silica nanofibers are generated and then assessed as a scaffold for controlled drug release with ketoprofen as a model drug. Poly (D, L-lactide-co-glycolide) is coated on the silica nanofibers to achieve slow burst release and prolonged cumulative release of 25 days. This study demonstrates an effective method of preparing hollow silica nanofibers and the use of such nanofibers for long-term release with high drug loading.

In this study, a low-cost, self-balancing crop spectral reflectance sensor (CSRS) was designed for real-time, nondestructive monitoring of the spectral reflectance and vegetation index of crops such as tomato and rapeseed. The sensor had a field of view of 30°, and a narrow-band filter was used for light splitting. The filter’s full width at half-maximum was 10 nm, and the spectral bands were 710 nm and 870 nm. The sensor was powered by a battery and used WiFi for communication. Its software was based on the Contiki operating system. To make the sensor work in different light intensity conditions, the photoelectric conversion automatic gain circuit had a total of 255 combinations of amplification. The gimbal of the sensor was mainly composed of an inner ring and an outer ring. Under the gravity of the sensor, the central axis of the sensor remained vertical, such that the up-facing and down-facing photosensitive units stayed in the horizontal position. The mechanical components of the sensor were designed symmetrically to facilitate equal mass distribution and to meet the needs of automatic balancing. Based on the optical signal transmission process of the sensor and the dark-current characteristics of the photodetector, a calibration method was theoretically deduced, which improved the accuracy and stability of the sensor under different ambient light intensities. The calibration method is also applicable for the calibration of other crop growth information sensors. Next, the standard reflectance gray scale was taken as the measurement variable to test the accuracy of the sensor, and the results showed that the root mean square error of the reflectance measured by the sensor at 710 nm and 870 nm was 1.10% and 1.27%, respectively; the mean absolute error was 0.95% and 0.89%, respectively; the relative error was below 4% and 3%, respectively; and the coefficient of variation was between 1.0% and 2.5%. The reflectance data measured by the sensor under different ambient light intensities suggested that the absolute error of the sensor was within ±0.5%, and the coefficients of variation at the two spectral bands were 1.04% and 0.39%, respectively. With tomato and rapeseed as the monitoring targets, the proposed CSRS and a commercial spectroradiometer were used to measure at the same time. The results showed that the reflectance measured by the two devices was very close, and there was a linear relationship between the normalized difference vegetation index of the CSRS and that of the commercial spectroradiometer. The coefficient of determination (R2) for tomato and rapeseed were 0.9540 and 0.9110, respectively.

Aberrant immune cell infiltrates and microcircumstances represent characteristic features of liver fibrosis. In this study, we profiled the transcriptomes of intrahepatic CD45+ immune cells, from mice, using single-cell RNA sequencing (scRNA-seq) technology to understand the landscape of intrahepatic immune cells during the pathogenesis of fibrosis. Analysis of approximately 10,000 single-cell transcriptomes revealed an increase in dendritic cells (DCs), macrophages, and neutrophils and a decrease in T and natural killer T (NKT) cells. In addition, we report changes in the transcriptomes of diverse immune cell types, implying a deteriorating intrahepatic immune microcircumstance. Furthermore, we uncovered a novel fibrosis-associated CD8 T (Ccl5+, Ccl4+) and CD4 T (mt-Co1+) cell subpopulation, which infiltrates fibrotic liver and is characterized by abnormal activation or inactivation as well as a TCR decline. The results from scRNA-seq and bulk immune repertoire sequencing (IR-seq) revealed an obvious decline in T cell receptor (TCR) clonotypes combined with shrinking VJ and VDJ segment usage, as well as lower complementarity-determining region 3 (CDR3) amino acid (AA) diversity from fibrotic liver. Interestingly, a deficiency of TCR IR (TcrbKO mice) led to a deterioration of liver fibrosis, coupled with activation of hepatic stellate cells (HSCs) induced by the upregulation of macrophage and γδ T cell distribution in fibrotic TcrbKO livers. Our findings reveal the landscape and dynamics of single immune cells in liver fibrosis, and clarify the protective role of TCR IR in response to chronic liver injury.

Gut microbiota (GM) modifies the intrahepatic immune microenvironment, but the underlying mechanisms remain poorly understood. Liver fibrosis-associated imprinting is predicted to be reflected in GM. This study investigated the link between GM and the intrahepatic T cell receptor (TCR) immune repertoire (IR), and whether GM modulates the intrahepatic immune microenvironment via TCR IR during liver fibrosis. We analyzed the correlation between GM and TCR IR during liver fibrogenesis. Accordingly, 16S rRNA gene sequencing (16S-seq) and bulk immune repertoire sequencing (IR-seq) were performed to characterize GM and intrahepatic TCR IR. Fecal microbial transplant (FMT) and TCRβ knockout (TcrbKO) mouse models were employed to determine the biological link between GM and TCR IR in liver fibrosis. We found that GM and intrahepatic TCR IR are highly correlated, with both showing reduced diversity and centralized distribution during liver fibrosis. The restoration of normal intestinal microbiota may reshape intrahepatic TCR IR and delay liver fibrosis. Interestingly, TCR IR ablation abrogated the impact of GM on liver fibrogenesis. Furthermore, GM modulated hepatic stellate cell (HSC) activation via TCR IR-mediated intrahepatic immune milieu. Our study demonstrates that GM, which exhibits cross-talk with the intrahepatic TCR IR, influences the intrahepatic immune microenvironment and liver fibrosis progression.

We study an initial boundary value problem for Kirchhoff-type parabolic equation with the fractional p-Laplacian. We first discuss the blow up of solutions in finite time with three initial energy levels: subcritical, critical and supercritical initial energy levels. Then we estimate an upper bound of the blowup time for low and for high initial energies.

In the framework of fractional Sobolev space, using Nehari manifold and concentration compactness principle, we study a minimization problem in the whole space involving the fractional Laplacian. Firstly, we give a Lions type lemma in fractional Sobolev space, which is crucial in the proof of our main result. Then, by showing a relative compactness of minimizing sequence, we obtain the existence of minimizer for the above-mentioned fractional minimization problem. Furthermore, we also point out that the minimizer is actually a ground state solution for the associated fractional Schrodinger equation

Research on efficient sensitizers for dye-sensitized solar cells (DSSCs) is in high demand to further improve the device efficiency, which can be accelerated through computational protocols. However, characterizing the photovoltaic properties of a sensitizer relies on expensive theoretical simulations for molecular excited states, making it a great challenge to achieve cost-effective performance prediction. In this study, an accurate and robust model is established by combining deep learning (DL) technique and quantum chemical (QC) calculation. By exclusively utilizing ground-state-related features as initial descriptors, a feedforward neural network is employed to predict the averaged light-harvesting efficiency and photocurrent density associated with absorption for dyes in DSSCs. The DL algorithm achieves a Pearson correlation coefficient exceeding 0.9 when compared to QC results, qualitatively reproducing experimental observations and effectively revealing relevant molecular design principles. Furthermore, the reliability of this approach is validated by the assessment of six newly designed molecules. The DL prediction exhibits a high consistency with the calculated result, indicating its potential in the discovery of prospective materials. Remarkably, the DL method shows a substantial advantage in terms of speed, being capable of calculations that are millions of times faster than comparable QC calculations, which provides an efficient tool for identifying candidates with preferable photovoltaic performance. The proposed model is expected to contribute to the rapid screening of sensitizers with desired photo-physical properties and to discovering new design strategies for high-performance DSSCs. [ABSTRACT FROM AUTHOR]

Neuronal PER-ARNT-SIM (PAS) domain protein 4 (NPAS4) is a protective transcriptional regulator whose dysfunction has been linked to a variety of neuropsychiatry and metabolic diseases. As a member of the basic helix-loop-helix PER-ARNT-SIM (bHLH-PAS) transcription factor family, NPAS4 is distinguished by an ability to form functional heterodimers with aryl hydrocarbon receptor nuclear translocator (ARNT) and ARNT2, both of which are also bHLH-PAS family members. Here, we describe the quaternary architectures of NPAS4-ARNT and NPAS4-ARNT2 heterodimers in complexes involving DNA response elements. Our crystallographic studies reveal a uniquely interconnected domain conformation for the NPAS4 protein itself, as well as its differentially configured heterodimeric arrangements with both ARNT and ARNT2. Notably, the PAS-A domains of ARNT and ARNT2 exhibit variable conformations within these two heterodimers. The ARNT PAS-A domain also forms a set of interfaces with the PAS-A and PAS-B domains of NPAS4, different from those previously noted in ARNT heterodimers formed with other class I bHLH-PAS family proteins. Our structural observations together with biochemical and cell-based interrogations of these NPAS4 heterodimers provide molecular glimpses of the NPAS4 protein architecture and extend the known repertoire of heterodimerization patterns within the bHLH-PAS family. The PAS-B domains of NPAS4, ARNT, and ARNT2 all contain ligand-accessible pockets with appropriate volumes required for small-molecule binding. Given NPAS4's linkage to human diseases, the direct visualization of these PAS domains and the further understanding of their relative positioning and interconnections within the NPAS4-ARNT and NPAS4-ARNT2 heterodimers may provide a road map for therapeutic discovery targeting these complexes. [ABSTRACT FROM AUTHOR]

A large family of two-dimensional (2D) transition metal carbides, MXene, has demonstrated potential applications for electrochemical energy storage. 2D MXene sheets may buffer large volume changes and form a 3D conductive network to facilitate the electronic transfer of working electrodes. However, multilayer Ti3C2Tx material could only deliver a moderate capacity in sodium ion battery cells, below the requirement of commercial applications. Herein, we decorated multilayer MXene (Ti3C2Tx) with Sb nanoparticles (NPs) via a facile solution-phase method, in which Sb NPs with a diameter of about 5–10 nm are absorbed on the surface of MXene layers by the electrostatic attraction action. The hybrid material Ti3C2Tx@Sb-0.5 delivers a higher reversible capacity of 200 mA h g−1 at 0.1 A g−1 than that of pure Ti3C2Tx (90 mA h g−1), and shows a much better capacity retention of nearly 98% after 500 cycles compared with Sb NPs. Also, it achieves superior rate performance (remaining a capacity of 127 mA h g−1 at 2 A g−1) and excellent long-term stability (a capacity retention of almost 92.3% after 8000 cycles). These results indicate that Ti3C2Tx@Sb-0.5 possess a potential for high-performance sodium ion batteries anodes. [ABSTRACT FROM AUTHOR]

In order to yield a marketable product, hand fruit thinning (HFT) has become the major but costly management practice in modern pear planting. Two kinds of new blossom thinners for pear blossom thinning were developed, which are tractor-mounted three arms blossom thinner (TTBT) and hand-held electric blossom thinner (HEBT). Four treatments for 24 trunk type 'Cuiguan' pear trees (7 years) were tested. They are TTBT combined with HFT, HEBT combined with HFT, hand blossom thinning (HBT) combined with HFT, and HFT only. Pear trees were divided into 4 groups equally. Four indexes were used to evaluate the test: flower reserve rate, fruit set rate, work efficiency and cost, fruit yield, and quality. Pear canopy was divided into the inner, middle, and outer 3 layers in the top view. 20 inflorescence samples were selected for each layer. Field tests showed: there was no obvious difference in quality between mechanical blossom thinning and HBT, and the working stability of TTBT was higher than other treatments. Mechanical blossom thinning decreased the fruit set rate to a certain degree, but did not reduce the yield and quality of harvesting. TTBT could save 61.35% operation time compared with HFT, and the profitable area was 5845.76 m². TTBT is suitable for large-scale sparse layer trunk-type pear orchards. HEBT could save 36.01% operation time compared with HFT, and the profitable area was 663.96 m². HEBT is suitable for small and medium-sized trunk-type pear orchards. Blossom thinning can improve the average weight of high quality fruit and brix of sugar solids. [ABSTRACT FROM AUTHOR]

The Fresnel diffraction of an aperture with a rough edge is studied in this paper. Circular and elliptical apertures with sinusoidal and random edges are chosen as examples to investigate the influence of the aperture edge on the diffraction. The numerical calculation results indicate intuitively the variations of the transverse and longitude diffraction intensity distributions with the edge parameters of the aperture. The data files of aperture models are obtained through the numerical calculations, and the aperture samples are obtained with the help of a liquid crystal light modulator (LCLM). Thus, the practical experiments of the diffractions of apertures with rough edges are carried out. The measured results are consistent with the calculated ones. The approximate analytic expressions of the diffraction by the modified aperture are deduced on the basis of the Fresnel diffraction theory and the statistic optics, and the reasonable explanations for the influence of edge parameters on the diffraction are given through the theoretical analysis. [ABSTRACT FROM AUTHOR]

Understanding the role of humic substances in soils is important for developing and utilizing organic fertilizers or soil amendments for sustainable agriculture. The objective of this study was to determine the effects of different fractions of humic acids derived from Leonardite on enzymatic activities and bioavailability of nutrients in a soil. The experiment was carried out by mixing different factions of humic acids with a soil and incubated for 70 d. The treatments included five factions of humic acids (HS1 (low molecular weight), HS2 (medium molecular weight), HS3 (large molecular weight, SED (sediment of fractions), HS (mixture of HS1, HS2, and HS3)), raw Leonardite (IM) and a control (no addition of humic acid). Experimental results showed that application of humic acids significantly improved acid and alkaline phosphatase activities, especially with HS1. Humic substances with high molecular weights significantly inhibit urease activity, and the optimal application rate was 600 kg/hm² of humic substances with the high molecular weights. Concentrations of NH4+-N were decreased with increasing humus applications. All treatments (HSmix, HS1, HS2, HS3, IM, SED) did not affect the soil contents of Ca, although soil concentrations of K, P, Cu, Zn were increase significantly when small molecular weight humus (HS1) was applied. [ABSTRACT FROM AUTHOR]