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Abstract In the design and optimisation of marine wireless communication and navigation systems, a thorough investigation of radio wave propagation characteristics under atmospheric ducting conditions is essential. The authors aim to enhance the efficiency of radio wave propagation loss prediction in marine atmospheric ducting environments, proposing a prediction model based on Fast Reordered‐Alternate Direction Decomposition (FR‐ADD). By approximating the diffraction term into three independent components, exploiting the commutative properties of the Fourier transform to reduce the spatial dimensions, and incorporating a rapid algorithm for the parabolic equation, the model optimises the stepping process and significantly improves computational efficiency. Simulation experiments demonstrate that, in the long‐distance and complex marine ducting environments, the model not only maintains prediction accuracy but also substantially reduces computational load and prediction time, effectively realising over‐the‐horizon propagation prediction. In the experiment of radio wave propagation characteristics in the Yellow and Bohai Seas, the simulation data from the FR‐ADD model showed significant correlation with actual measurements and simulations from the AREPS software, confirming the method's efficiency and practicality.

Abstract The repair of bone defects remains a major challenge in the clinic, and treatment requires bone grafts or bone replacement materials. Existing biomaterials have many limitations and cannot meet the various needs of clinical applications. To treat bone defects, we constructed a nanohydroxyapatite (nHA)/methylacrylylated silk fibroin (MASF) composite biological scaffold using photocurable 3D printing technology. In this study, scanning electron microscopy (SEM) was used to detect the changes in the morphological structure of the composite scaffold with different contents of nanohydroxyapatite, and FTIR was used to detect the functional groups and chemical bonds in the composite scaffold to determine the specific components of the scaffold. In in vitro experiments, bone marrow mesenchymal stem cells from SD rats were cocultured with scaffolds soaking solution, and the cytotoxicity, cell proliferation, Western blot analysis, Quantitative real-time PCR analysis, bone alkaline phosphatase activity and alizarin red staining of scaffolds were detected to determine the biocompatibility of scaffolds and the effect of promoting proliferation and osteogenesis of bone marrow mesenchymal stem cells in vitro. In the in vivo experiment, the skull defect was constructed by adult SD rats, and the scaffold was implanted into the skull defect site. After 4 weeks and 8 weeks of culture, the specific osteogenic effect of the scaffold in the skull defect site was detected by animal micro-CT, hematoxylin and eosin (HE) staining and Masson's staining. Through the analysis of the morphological structure of the scaffold, we found that the frame supported good retention of the lamellar structure of silk fibroin, when mixed with nHA, the surface of the stent was rougher, the cell contact area increased, and cell adhesion and lamellar microstructure for cell migration and proliferation of the microenvironment provided a better space. FTIR results showed that the scaffold completely retained the β -folded structure of silk fibroin, and the scaffold composite was present without obvious impurities. The staining results of live/dead cells showed that the constructed scaffolds had no significant cytotoxicity, and thw CCK-8 assay also showed that the constructed scaffolds had good biocompatibility. The results of osteogenic induction showed that the scaffold had good osteogenic induction ability. Moreover, the results also showed that the scaffold with a MASF: nHA ratio of 1: 0.5 (SFH) showed better osteogenic ability. The micro-CT and bone histometric results were consistent with the in vitro results after stent implantation, and there was more bone formation at the bone defect site in the SFH group.This research used photocurable 3D printing technology to successfully build an osteogenesis bracket. The results show that the constructed nHA/MASF biological composite material, has good biocompatibility and good osteogenesis function. At the same time, in the microenvironment, the material can also promote bone defect repair and can potentially be used as a bone defect filling material for bone regeneration applications.

ABSTRACTChilling injury is the dominant factor for quality deterioration and marketability suffers of cucumber fruit during low-temperature storage. Nitric oxide (NO) is a kind of endogenous signaling molecule that significantly regulates the abiotic stress response. In the current investigation, the membrane lipid and energy metabolism were investigated after cucumber fruit was exposed to a sodium nitropruside (SNP) solution that acts as a NO donor before being kept at 4°C for 12 days. The results illustrated that SNP treatment reduced chilling injury and lightened the increase in membrane permeability under cold stress, maintaining a better quality. Subsequently, SNP regulated lipid metabolism by reducing the expression of genes encoding PLA, PLD, lipase, and LOX and decreasing the activities. Compared to the control, the SNP-treated fruit exhibited higher ATP and EC (energy charge) levels. Moreover, SNP-treated suppressed the decrease of H+-ATPase, Ca2+-ATPase, SDH, and CCO activity, which is involved in energy metabolism. The above results showed that exogenous nitric oxide might be an effective method to alleviate the chilling damage in postharvest cucumber fruit by modifying membrane lipids and energy metabolism.

BACKGROUND Germanium is an essential element for life. With the discovery of germanium-enriched soils all over China in recent years, the development of germanium-enriched agriculture has gradually gained attention. OBJECTIVES To study the characteristics and range of germanium-enriched soil in typical black soil areas, and to analyze factors affecting soil germanium content. METHODS Germanium content in soil was determined by inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-optical emission spectrometry (ICP-OES). RESULTS The germanium content in the topsoil of the Nehe area was 0.74-1.78mg/kg, with an average value of 1.13mg/kg. There was a large area of concentrated and contiguous germanium-enriched soil in the Nehe area, about 599.8km2, accounting for 9.31% of the city's area. The source of germanium in the soil was the middle Pleistocene upper Huangshan Formation and the upper Pleistocene Guxiangtun Formation. The content of germanium in swamp soil and black soil was highest. CONCLUSIONS The germanium content in the soil is related to the stratum, soil type and human activities. Soybeans have the highest germanium content in the crops. This area has good potential for the development of germanium-enriched agriculture.

Electron beam irradiation is a physical fungicidal technique that has emerged as a potential application in China. However, its antifungal activity and mechanism against Rhizopus oryzae have not been reported. Thus, this study aimed to investigate the antifungal activity and mechanism of electron beam irradiation of R. oryzae. The antifungal activity analysis showed that the D10 value and complete elimination dose of R. oryzae irradiated by electron beam were 1.73 kGy and 8.08 kGy, respectively. Electron beam irradiation has a strong inhibitory effect on the filamentous biomass of R. oryzae. To reveal the antifungal mechanism of electron beam against R. oryzae, this study analyzed the dynamic changes in the cell wall, cell membrane, and oxidative stress induced by different irradiation doses. The results showed that electron beam irradiation destroyed the cell wall structure of R. oryzae, increasing chitinase activity and decreasing chitin content. Cell membrane integrity is disrupted, increasing relative conductivity, decreasing pH values, and decreasing soluble protein content. Electron beam irradiation causes oxidative stress in cells, increasing H2O2 content, decreasing antisuperoxide anion activity, decreasing DPPH free radical scavenging activity, and inhibiting defense enzyme (CAT and SOD) activity. This phenomenon indicates that electron beams can cause structural damage to and metabolic dysfunction of cells and disorders of redox homeostasis, which may be the main cause of growth inhibition and cell death in R. oryzae.

To study the effects of different storage temperatures (25, 15, 4 ℃) after harvest on the sugar components and related enzyme activities of "Shixia" longan fruits. The longan pulp soluble solid content (SSC), the content of three main sugars and the changes in the activities of sugar metabolism-related enzymes were measured. Principal component analysis and load factor analysis were performed on samples at different storage temperatures and various periods, and the correlation analysis of each index was performed. The results showed that the SSC of longan stored at 25 ℃ decreased the fastest, from 23.5% to 22.0% after 8 days of storage, and the sucrose content decreased the fastest, but the glucose and fructose content showed an upward trend; both 15℃ and 4 ℃ could effectively delay SSC. The decrease in SSC of longan stored at 4 ℃ was slower and the sucrose and glucose content decreased the slowest, but the decrease in fructose content was faster than 15 ℃. The acid invertase (AI), neutral invertase (NI) and sucrose synthase (SS) activities of longan pulp stored at different temperatures all increase with the storage time, the amplitude and speed of the increase was the fastest at 25 °C, at 15 °C was secondly, and the 4 ℃ rise was the most gentle, indicating that low temperature significantly inhibited the increase in the activity of sucrose metabolizing enzymes. Correlation analysis showed that the sucrose content of longan stored at different temperatures had a very significant positive correlation with SSC, indicating that SSC could reflect the sucrose content to a certain extent; the sucrose content had a significant positive correlation with the glucose content, and it also had significant negative correlation with AI, NI, and SS. It was inferred that glucose and fructose were degraded from sucrose; glucose content and fructose content were extremely significantly positively correlated, but the two decline patterns in 15 ℃ and 4 ℃ storage fruits were inconsistent, suggesting that the consumption of the two was different. The above results indicate that low temperature could significantly inhibit the increase of sugar metabolism and related enzyme activities in longan fruit, thereby slowing down the decomposition of sugar during storage and prolonging the storage time. Among them, the storage effect at 4 ℃ was the best.

The understanding of the spatial distribution of soil organic carbon (SOC) and its influencing factors is crucial for comprehending the global carbon cycle. However, the impact of soil geochemical and climatic conditions on SOC remains limited, particularly in dryland farming areas. In this study, we aimed to enhance the understanding of the factors influencing the distribution of SOC in the drylands of the Songliao Plain, Northeast China. A dataset comprising 35,188 measured soil samples was used to map the SOC distribution in the region. Multiple linear regression (MLR) and random forest models (RFM) were employed to assess the importance of driving indicators for SOC. We also carried out partial correlation and path analyses to further investigate the relationship between climate and geochemistry. The SOC content in dryland soils of the Songliao Plain ranged from 0.05% to 11.63%, with a mean value of 1.47% ± 0.90%. There was a notable increasing trend in SOC content from the southwest to the northeast regions. The results of MLR and RFM revealed that temperature was the most critical factor, demonstrating a significant negative correlation with SOC content. Additionally, iron oxide was the most important soil geochemical indicator affecting SOC variability. Our research further suggested that climate may exert an indirect influence on SOC concentrations through its effect on geochemical properties of soil. These insights highlight the importance of considering both the direct and indirect impact of climate in predicting the SOC under future climate change. [ABSTRACT FROM AUTHOR]

Background The calmodulin-like (CML) protein is a crucial Ca2+-binding protein that can sense and conduct the Ca2+ signal in response to extracellular stimuli. The CML protein families have been identified and characterized in many species. Nevertheless, scarce information on cucumber CML is retrievable. Methods In this study, bioinformatic analyses, including gene structure, conserved domain, phylogenetic relationship, chromosome distribution, and gene synteny, were comprehensively performed to identify and characterize CsCML gene members. Spatiotemporal expression analysis in different organs and environment conditions were assayed with real-time quantitative polymerase chain reaction (qRT-PCR). Results Forty-four CsCMLs family members were well characterized, and the results showed that the 44 CsCML proteins contained one to four EF-hand domains without other functional domains. Most of the CsCML proteins were intron-less and unevenly distributed on seven chromosomes; two tandemly duplicated gene pairs and three segmentally duplicated gene pairs were identified in the cucumber genome. Cis-acting element analysis showed that the hormone, stress, and plant growth and development-related elements were in the promotor regions. In addition, spatiotemporal expression analysis revealed distinctive expression patterns for CsCML genes in different tissues and environmental conditions, and a putative protein interaction network also confirmed their potential role in responding to various stimuli. These results provide a foundation for understanding CsCMLs and provide a theoretical basis for further study of the physiological functions of CsCMLs.

There are three traditional surgical approaches to hemiarthroplasty (HA) for femoral neck fractures, respectively, the anterior approach (AA), the lateral approach (LA) and the posterior approach (PA). However, the optimum approach is still controversial, the purpose of this meta-analysis is to identify the merits and demerits of all three approaches. All clinical published studies in PubMed, Web of Science, Embase, and the Cochrane Library from January 2000 to April 2022 were searched which compared different surgical approaches and covered surgery-related outcomes and frequent complications. Five randomized controlled trials and 26 cohort studies for a total of 31 clinical trials were included in the meta-analysis. The dislocation of PA was significantly higher than LA (OR: 3.00 95% CI: 2.25–4.01 I2 = 27% P