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Objective To observe the systemic reactions （SRs） associated with subcutaneous immunotherapy （SCIT） using dust mite allergen and to analyze potential risk factors. Methods The occurrence of SRs among 230 patients with allergic rhinitis （AR） who received house dust mite SCIT from December 2019 to December 2022 was retrospectively analyzed， and related risk factors were identified. Results A total of 5 422 injections were given to 230 patients， with an SRs incidence rate of 2.4% per injection and 20.0% per patient. Most SRs were grade I （51.9%）， and no fatal SRs occurred. Symptoms primarily affected the respiratory system for 111 times （84.7%）. Elevated peripheral blood eosinophil count （OR （95% CI）=6.02 （1.76， 20.60）， P = 0.004） and high levels of house dust mite-specific IgE （OR （95% CI）=1.01 （1.00， 1.01）， P = 0.016） were identified as risk factors for SRs， respectively. Conclusions Children with AR allergic to dust mites may experience SRs during SCIT with standardized dust mite allergen preparations， whereas the overall safety of SCIT is good. High eosinophil count and high levels of house dust mite-specific IgE are risk factors for SRs during SCIT.

Under the influences of AC-DC coupling， uncoordinated network-source development， and new energies that fail to meet the demand of grid-related performance， power system stability is becoming a point of extreme gravity. The correlation characteristics of transient voltage and power angle stability of the receiving-end grid are analyzed. Two transient instability modes with transient voltage and transient power angle instability as the dominant causal factors and their specific evolution processes are discussed based on the transient stability mechanism. Afterward， the effects of the optimal control measures on grid layout， power structure， network-source coordination， power distribution， and source-load interaction on optimizing the transient stability are reviewed and verified， and the traditional stability control measure of limiting unit output is not adopted. The study of the evolution of transient instability patterns and simulation analysis provides a reliable reference for identifying transient instability scenarios of key units in the receiving-end grid and formulating control measures.

With the rapid load growth and the increasing density of power grids， the overrun short-circuit current becomes increasingly aggravated. To accurately assess the short-circuit current level of the system is crucial to ensure the safe and stable operation of the power grid. Therefore， a short-circuit current evaluation method based on the branch fault current of the circuit breaker is proposed. In view of the double-bus double-section wiring substations at voltage levels of 220 kV and below and 500 kV three-to-two wire substations， the paper analyzes the short circuit current flowing through the circuit breaker in case of different fault locations， switch-off of circuit breakers， etc. Moreover， it proposes a calculation method of the short circuit current that the circuit breaker requires in the single-jump single-weight stage of single-phase fault occurring at the line outlet and determines the maximum short circuit current required to block the circuit breaker in the substation. Additionally， it specifies a short circuit current calibration standard that the maximum short circuit current flowing through the circuit breakers after the fault should not exceed their breaking capacities. Finally， the effectiveness of the proposed evaluation method is verified through case analysis.

The transient forced excitation of the traditional excitation system used for synchronous condenser is limited and unmaintainable. A flexible excitation system can improve the crest value of transient forced excitation and maintain the forced excitation capacity during and after faults through DC bus voltage control. Therefore， a study is conducted on applying a flexible excitation system for critical units to improve the transient stability characteristics of local power grids. The hardware topology and control method of flexible excitation are introduced， and the flexible excitation control objective to enhance the transient stability characteristics of the units is analyzed. The flexible excitation is applied to the critical units in the actual grid at the receiving end with transient stability problems. The transient stability enhancement effect of the grid is verified in the simulation after the application. The results show that applying flexible excitation to a limited number of critical units can effectively improve the transient stability characteristics of power grid.

In the aftermath of power disturbance in power grid with high-penetration renewable integration， the frequency response trajectory is more likely to present large frequency deviation and high rate of change， which leads to a significant effect on frequency protection action. In order to accurately predict the frequency response characteristics of the system under the strong random operation mode， this paper uses the fast kernel learning algorithm based on the pseudo-inverse of the kernel matrix and integrates the key feature quantities obtained from the common mode frequency analysis to propose a frequency risk assessment method for power grid with high-penetration renewable integration. This method uses a set of mutually independent sample data to directly construct the regular term function through the pseudo-inverse operation of the kernel matrix， avoiding the convergence problems caused by the iterative solution of general machine learning algorithms without reducing the generalization ability of the learning results. The analysis of an example in the IEEE 39-node system verifies the effectiveness of the proposed method.

In order to study the characteristics of carbon emission of tobacco production in China and promote green low-carbon system for tobacco production, the tobacco carbon footprint in southern Henan tobacco growing area was quantitatively analyzed based on the agricultural carbon footprint theory and farmers' survey data. The characteristics of carbon emissions in the tobacco production process were clarified, and the relationship between the carbon footprint of tobacco production fertilizers and the output value per unit area, and that between tobacco yield per unit area and the carbon footprint of different functional units in the southern Henan tobacco growing area were analyzed. The results showed that the carbon footprints per unit area, per unit yield, and per unit production value of the tobacco production system in southern Henan were 12 630.03 kg CO2-eq ⋅ hm-2, 6.62 kg CO2-eq ⋅ kg-1, and 0.21 kg CO2-eq ⋅ ¥-1, respectively. Coal used for tobacco curing, electricity for tobacco curing, agricultural film, and fertilizer application were the main sources of the carbon footprint of tobacco production in southern Henan, accounting for 67.4%, 14.5%, 6.1%, and 4.0%, respectively. Based on the higher output value per unit area, the carbon footprints of fertilizer and nitrogen fertilizer were found to be too high for 28.04% of the farmers surveyed. Based on the lower carbon footprint per unit area, tobacco yield was too low for 20.56% of the farmers surveyed. Therefore, the key to developing green tobacco production in southern Henan tobacco growing area is to maintain tobacco yield and reduce carbon emissions in production, and promoting clean energy curing houses and optimizing fertilizer management will be important measures for green tobacco production in the future. [ABSTRACT FROM AUTHOR]

Objective: To investigate the microRNA (miR)-150 expression level in human osteosarcoma cell lines (Saos-2, MG-63) and its function in cell proliferation, and to explore the potential molecular mechanisms. 
 Methods: MiR-150 expression levels in human osteosarcoma cell lines (Saos-2, MG-63) and normal osteoblast cell line (NHOst) were detected by relative quantitative real-time PCR (qRT-PCR). MiR-150 was overexpressed in Saos-2 and MG-63 cells by lentivirus infection. Cell proliferation rates were monitored by MTS assay. RUNX2 and β-actin protein levels were examined by Western blot. Inhibitory effect of miR-150 on binding RUNX2 3'-UTR was detected by Dual-Luciferase assay.
 Results: MiR-150 expression level is lower in human osteosarcoma cell lines (Saos-2, MG-63) compared to the normal osteoblast cell line (NHOst) (0.23±0.02 and 0.32±0.03 vs 1.00±0.02), which showed statistical significance (P<0.01). After lentivirus infection, miR-150 level increased in Saos-2 (P<0.01) and MG-63 cells (P<0.01). Overexpression of miR-150 decreased cell proliferation and RUNX2 protein level in Saos-2 and MG-63 cells. The binding of miR-150 to RUNX2 3'-UTR decreased luciferase activity by 69% in Saos-2 cells (P<0.05) and 59% in MG-63 cells (P<0.05). Administration of exogenous RUNX2 recovered the cell proliferation in miR-150 overexpressed Saos-2 and MG-63 cell lines (P<0.01).
 Conclusion: MiR-150 inhibites proliferation in human osteosarcoma cell lines through binding to RUNX2 3'-UTR, resulting in the reducion of RUNX2 protein level.