94 research outputs found

    Design of a trichogramma balls UAV delivery system and quality analysis of delivery operation

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    The field boundaries in our country are complex. In attempts to control pests via trichogramma-dominated biological control, the long-term practice of manual trichogramma release has resulted in low control efficiency, thereby impeding sustainable agricultural development. Currently, the novel approach involves utilizing Unmanned Aerial Vehicles (UAVs) for trichogramma balls delivery; however, the system is still in its nascent stages, presenting opportunities for enhancement in terms of stability and accuracy. Furthermore, there is a notable absence of comprehensive operational quality assessment standards. In this study, we establish a stable and accurate trichogramma balls delivery system using a four-axis plant protection UAV and introduce a comprehensive evaluation method for trichogramma balls delivery system. When dealing with fields with complex boundaries, it is beneficial to divide them into rectangular, trapezoidal, and stepped small fields at the boundary and perform operations within these small fields. According to our proposed evaluation method, when only considering the effect of field operations, the most effective boundary division shape is trapezoidal, followed by rectangular. and the worst is stepped. If both field operation effectiveness and the utilization effect of placed trichogramma balls are considered, the optimal shape is trapezoidal, then stepped, with rectangular being the least effective. Consequently, for UAV sub-area operations in complex boundary fields, it is advisable to divide the boundaries into trapezoids wherever possible. Field experiment results indicate that the system’s delivery area can reach up to 4158 m²/min and the coverage rate of released trichogramma balls can exceed 97%. The system design methodology and comprehensive operational quality evaluation method proposed in this article provide technical support and scientific basis for the application and promotion of UAV delivery trichogramma balls system. This is conducive to the high-quality development of agriculture

    Construction of porphyrinic manganese-organic frameworks based on structural regulation for electrochemical determination of nitrobenzene in water and vegetable samples

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    Nitrobenzene (NB) is one of the major organic pollutants that has seriously endangered human health and the environment even in trace amounts. Therefore, it is of great significance to detect trace NB efficiently and sensitively. Herein, a porphyrinic metal-organic framework (MOF) of Mn-PCN-222 (PCN, porous coordination network) was first synthesized by the coordination between Zr6 cluster and tetrakis (4-carboxyphenyl)-porphyrin-Mn (Ⅲ) (MnTCPPCl) ligand. To regulate its structure and the electrochemical properties, a phenyl group was inserted in each branched chain of TCPP to form the TCBPP organic ligand. Then, we used Zr6 clusters and manganese metalloporphyrin (MnTCBPPCl) to synthesize a new porphyrin-based MOF (Mn-CPM-99, CPM, crystalline porous material). Due to the extended chains of TCPP, the rod-shaped structure of Mn-PCN-222 was switched to concave quadrangular bipyramid of Mn-CPM-99. Mn-CPM-99 exhibited higher porosity, larger specific surface area, better electrochemical performances than those of Mn-PCN-222. By using modular assembly technique, Mn-CPM-99 film was sequentially assembled on the surface of indium-tin-oxide (ITO) to prepare an electrochemical sensor (Mn-CPM-99/ITO). The proposed sensor showed excellent electrochemical reduction of NB and displayed three linear response ranges in the wide concentration ranges. The obtained low limit of detection (LOD, 1.3 nM), high sensitivity and selectivity, and good reproducibility of the sensor for NB detection fully illustrate that Mn-CPM-99 is an excellent candidate for electrochemical sensor interface material. Moreover, the sensor was successfully applied to the detection of NB in lake water and vegetable samples showing satisfactory recovery of 98.9%–101.8%

    Ground beetle assemblages in Beijing’s new mountain forests

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    Mature forests have been almost completely destroyed in China’s northern regions, but this has been followed by large-scale reforestation in the wake of environmental degradation. Although future forest plantations are expected to expand over millions of hectares, knowledge about the ecology and biodiversity of China’s replanted forests remains very limited. Addressing these knowledge gaps, we recorded ground beetle (Coleoptera: Carabidae) communities in five secondary forest types: plantations of Chinese Pine (Pinus tabulaeformis) and Prince Rupprecht’s Larch (Larix principis-rupprechtii), Oak (Quercus wutaishanica) and Asian White Birch (Betula platyphylla) woodlands, and naturally regenerated mixed forest. Species richness peaked in mixed forests, while pine and oak woodlands harboured discrete communities of intermediate species richness. Oak, pine and mixed forest habitats also showed high levels of species turnover between plots. Canopy closure was an important factor influencing ground beetle assemblages and diversity, and a number of forest specialist species only occurred in pine or oak forests. We believe that some forest specialists have survived earlier deforestation and appear to be supported by new plantation forests, but maintenance of secondary native oak and mixed forests is crucial to safeguard the overall species pool

    A systematic bibliometric analysis on the clinical practice of CGM in diabetes mellitus from 2012 to 2022

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    BackgroundContinuous glucose monitoring (CGM) has revolutionized diabetes management, but a comprehensive analysis of its clinical implementation is lacking. This study aims to explore CGM in diabetes practice over the past decade using bibliometric analysis. It will identify trends, research focal points, and provide a framework for future investigations.Materials and methodsThe Web of Science Core Collection (WOSCC) was utilized to acquire literature pertaining to the employment of continuous glucose monitoring (CGM) in diabetes that was published between the years 2012 and 2022, and to conduct a comprehensive analysis of the associated citation data. To achieve bibliometric visualization and analysis of the collated data, the bibliography package in the Rstudio(v.4.2.2), Citespace 6.2.R4, and VOS viewer were employed.ResultsA total of 3024 eligible publications were extracted from 91 countries, with the United States being the leading country in terms of the number of issued articles. Furthermore, the annual publication rate has shown a gradual increase during the past decade. Among the various journals in this field, DIABETES TECHNOLOGY & THERAPEUTICS was identified as the most highly cited one. Keyword clustering analysis of the extracted publications indicates that the research hotspots in the past decade have primarily focused on “continuous glucose monitoring”, “glycemic variability”, “type 1 diabetes”, “hypoglycemia”, and “glycemic control”. Moreover, the analysis of keyword emergence reveals that “Time In Range” and “Young Adult” represent the current research frontiers for the years 2012-2022.ConclusionThe concept of Time in Range (TIR) has garnered considerable attention as a significant area of inquiry and an emerging research trend in the clinical practice of Continuous Glucose Monitoring (CGM) for Diabetes Mellitus. Moreover, recent investigations have demonstrated a growing focus on young adults with type 1 diabetes as the research population of interest. In the foreseeable future, research endeavors will persist in the pursuit of improving glycemic management among young adults through the utilization of continuous glucose monitoring (CGM) technology, while also delving into the examination of the Time in Range metric via supplementary clinical investigations

    A note on the range of the product of two operators

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    Let H and K be two Hilbert spaces,and let A∈B(H),B∈B(K,H) be two bounded linear operators such that ind(A) ≤ 1,R(AB)⊆R(B) and R(B) is closed in H.A sufficient condition is given under which R(AB)=R(A)∩R(B).Furthermore,a counterexample is constructed such that R(AB)≠R(A)∩R(B)

    Associations of physical activity and soybean product consumption with psychological symptoms: a cross-sectional survey of Chinese university students

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    Abstract Introduction Declining physical activity among university students has become a concern, with increasingly poor dietary behaviors and other unfavorable factors having an impact on the occurrence of psychological symptoms. Previous studies have analyzed the association between moderate-to-vigorous physical activity (MVPA) and psychological symptoms, but few studies have investigated the association between soy product consumption and these symptoms. In addition, the associations between physical activity and soy product consumption with psychological symptoms have not been investigated. Methods In this study, 7267 university students from different regions of China were surveyed regarding physical activity, soy product consumption, and psychological symptoms. Binary logistic regression was used to analyze the associations among MVPA, soy product consumption, and psychological symptoms. A generalized linear model (GLM) was applied to further analyze the associations of MVPA and soy product consumption with psychological symptoms in this population. Results The detection rate of psychological symptoms among Chinese university students was 17.9%, with the rate among female students (18.9%) higher than that among male students (16.6%). The proportion of university students with MVPA  60 min/d was 76.1%, 19.3%, and 4.6%, respectively, and the proportion with soy product consumption ≤ 2 times/wk, 3–5 times/wk, and ≥ 5 times/wk was 25.8%, 42.4%, and 31.7%, respectively. The GLM showed that compared with university students who had MVPA  60 min/d and soy product consumption ≥ 6 times/week (OR = 0.198, 95% CI: 0.100–0.393, P  60 min/d and soy product consumption 3–5 times/week (OR = 0.221, 95% CI: 0.102–0.479, P < 0.001). Conclusion In terms of research, there is an association between physical activity and soy product consumption and psychological symptoms among university students. The results of our study suggest that integrated intervention for psychological symptoms among university students is needed from the perspectives of physical activity and dietary behavior to promote good mental health in this population

    Triglyceride glucose index as a predictor of mortality in middle-aged and elderly patients with type 2 diabetes in the US

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    Abstract Despite a wealth of research linking the triglyceride glucose index (TyG index) to metabolic diseases. However, little evidence links the TyG index to all-cause or CVD mortality in middle-aged and elderly individuals with type 2 diabetes (T2D). This study analyzed data from 2998 patients with T2D who participated in the National Health and Nutrition Examination Survey (NHANES) between 1999 and 2018. The TyG index and mortality in middle-aged and elderly T2D patients were investigated using Cox regression models. The nonlinear association between the TyG index and mortality can be understood with the help of a restricted cubic spline (RCS). During a median follow-up period of 82 months, 883 fatalities were observed from all causes and 265 from CVD. The TyG index was found to have a U-shaped relationship with all-cause and CVD mortality in T2D, with cutoffs of 8.95 and 9, respectively, according to the RCS. After controlling for other factors, an increase of 1 unit in the TyG index was related to an increase of 33% in all-cause mortality and 50% in CVD mortality when TyG was ≥ 8.95 and 9. When TyG < 8.95 and 9, with the change in the TyG index, the change in all-cause and CVD death was insignificant. Patients with T2D who are middle-aged or older, especially elderly patients, have higher TyG levels associated with increased mortality. In middle-aged and elderly patients with T2D, the TyG index may predict the probability of death from any cause and death from CVD

    SIW-Based Devices

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    With the development of microwave wireless communication technology, microwave passive frequency selectivity circuits are developing toward multi-function and miniaturization. Substrate-integrated waveguide (SIW) devices have good development prospects in miniaturization and integration. The research on devices based on SIW is lack unified theoretical combing. This chapter describes the novel circuits based on substrate-integrated waveguide, including filter, power divider, switch, phase shifter, diplexer, and crossover. This chapter describes the design methods and special properties of these circuits. The display of these circuits is expected to give some inspiration to your research
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