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Alfalfa (Medicago sativa L.) is an important and widely cultivated forage grass. The productivity and forage quality of alfalfa are severely affected by salt stress. Melatonin is a bioactive molecule with versatile physiological functions and plays important roles in response to various biotic and abiotic stresses. Melatonin has been proven efficient in improving alfalfa drought and waterlogging tolerance in recent studies. In our reports, we applied melatonin exogenously to explore the effects of melatonin on alfalfa growth and salt resistance. The results demonstrated that melatonin application promoted alfalfa seed germination and seedling growth, and reduced oxidative damage under salt stress. Further application research found that melatonin alleviated salt injury in alfalfa plants under salt stress. The electrolyte leakage, malondialdehyde (MDA) content and H 2 O 2 content were significantly reduced, and the activities of catalase (CAT), peroxidase (POD), and Cu/Zn superoxide dismutase (Cu/Zn-SOD) were increased with melatonin pretreatment compared to control plants under salt stress with the upregulation of genes related to melatonin and antioxidant enzymes biosynthesis. Melatonin was also involved in reducing Na + accumulation in alfalfa plants. Our study indicates that melatonin plays a primary role as an antioxidant in scavenging H 2 O 2 and enhancing activities of antioxidant enzymes to improve the salt tolerance of alfalfa plants.Plants 2020, 9, 220 2 of 17 world's irrigated land affected by saline or sodic globally [7,8]. Salinity has become one of the most important environmental stress factors impairing worldwide agricultural productivity. Under salinity conditions, the seed germination, growth and development processes of alfalfa are inhibited and they finally impair the herbage yield, as well as the forage quality [9]. Breeding new alfalfa cultivars with high salt tolerance is always needed. Genetic engineering and conventional breeding have been proven efficient for improving salt tolerance of various plant species [10][11][12][13]. However, they are time-consuming and complicated. Exogenous application of certain plant growth regulators such as phytohormone and other small molecules has been proven efficient at overcoming the harmful effects of salt stress on plants [14][15][16][17]. Moreover, plant growth regulators in low concentrations always play a role in plants, and are cost-effective. Foliar spraying of salicylic acid (SA) on faba bean inhibits Na + accumulation and lipid peroxidation, improving the antioxidant resistance and finally mitigating the damage caused by salinity [18]. Exogenously applied poly-γ-glutamic acid on wheat maintains the Na + and K + homeostasis and enhances antioxidant capacity by alleviating salinity damage under salt stress conditions [19]. Exogenous spermidine application to salt-stressed cucumber improves the photosynthetic capacity and the activity of key enzymes for CO 2 fixation by regulating the expression of related genes, and tolerance to salinity is thus...

Abstract. While nocturnal low-level jets (NLLJs) occur frequently in many parts of the world, the occurrence and other detailed characteristics of NLLJs over the Taklimakan Desert (TD) are not well known. This paper presents a climatology of NLLJs and coincident dust over the TD by analyzing multi-year ERA-Interim reanalysis and satellite observations. It is found that the ERA-Interim dataset can capture the NLLJs' features well by comparison with radiosonde data from two surface sites. The NLLJs occur in more than 60 % of nights, which are primarily easterly to east-northeasterly. They typically appear at 100 to 400 m above the surface with a speed of 4 to 10 m s −1 . Most NLLJs are located above the nocturnal inversion during the warm season, while they are embedded in the inversion layer during the cold season. NLLJs above the inversion have a strong annual cycle with a maximum frequency in August. We also quantify the convective boundary layer (CBL) height and construct an index to measure the magnitude of the momentum in the CBL. We find that the magnitude of momentum in the lower atmosphere from the top of the surface layer to the top of mixed layer is larger for NLLJ cases than for non-NLLJ cases, and in the warm season the downward momentum transfer process is more intense and rapid. The winds below the NLLJ core to the desert surface gain strength in summer and autumn, and these summer and autumn winds are coincident with an enhancement of aerosol optical depth. This indicates that the NLLJ is an important mechanism for dust activity and transport during the warm season over the Taklimakan.

Background: Post-operative pain management for patients undergoing thoracoscopy surgery is challenging for clinicians which increase both health and economic burden. The non-selective NMDA receptor antagonist esketamine possesses an analgesic effect twice that of ketamine. The application of esketamine might be beneficial in alleviating acute and chronic pain after thoracic surgery. The current study describes the protocol aiming to evaluate the analgesic effect of esketamine after pulmonary surgery via visual analog scale (VAS) score for acute and chronic pain.Methods: A multi-center, prospective, randomized, controlled, double-blind study is designed to explore the analgesic effect of esketamine in randomized patients undergoing video-assisted thoracoscopic surgery (VATS) with general anesthesia. Patients will be randomly assigned to Esketamine Group (Group K) and Control Group (Group C) in a ratio of 1:1. Group K patients will receive esketamine with a bolus of 0.1 mg/kg after anesthesia induction, 0.1 mg/kg/h throughout the operation and 0.015 mg/kg/h in PCIA after surgery while Group C patients will receive the same volume of normal saline. The primary outcome is to measure the pain intensity through the VAS score at 3 months after the operation. The secondary outcome includes VAS score at 1, 4, 8, 24, and 48 h and on the 7th day and 1 month after the operation, complications, ketamine-related neurological side effects, recovery time of bowel function, and total amount of supplemental analgesics.Discussion: The results of the current study might illustrate the analgesic effect of esketamine for patients undergoing thoracoscopy pulmonary surgery and provide evidence and insight for perioperative pain management.Study Registration: The trial was registered with Chinese Clinical Trial Registry (CHICTR) on Nov 18th, 2020 (ChiCTR2000040012).

Objectives Dexmedetomidine (DEX) is a selective α2-adrenoceptor agonist that has anti-inflammatory and cardioprotective effects in myocardial ischemia/reperfusion (I/R) injury. The present study aimed to investigate the underlying mechanism by which DEX protects against myocardial I/R. Methods Sprague Dawley rats were subjected to either sham operation or myocardial I/R, which was induced by ligating the left anterior descending coronary artery for 30 min followed by reperfusion for 120 min. Rats were treated with either DEX or saline prior to surgery. We measured heart infarct size, serum cardiac Troponin I (cTnI), cardiac High mobility group box-1 (HMGB1) expression, myocardial apoptosis and cytokine production of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). Besides, we evaluated the heart function at 4 weeks post-reperfusion by echocardiography. Unilateral vagotomy or inhibition of the α7 nicotinic acetylcholine receptor (α7nAChR) with methyllycaconitine (MLA) was applied to investigate whether DEX-induced cardioprotection is mediated via the cholinergic anti-inflammatory pathway. Cardiac-selective overexpression of HMGB1 was administered to further confirm if HMGB1 is a key anti-inflammatory target during DEX-induced cardioprotection. Results DEX pretreatment significantly attenuated I/R-induced cardiac damage, as evidenced by decreases in short-term injury indicators including myocardial infarct size, cTnI release, myocardial apoptosis, cardiac HMGB1 expression, IL-6 and TNF-α production, as well as improvement on long-term cardiac function at 4 weeks post-reperfusion. These effects were partially reversed by either unilateral vagotomy or methyllycaconitine treatment. Besides, cardiac HMGB1-overexpression nearly abolished DEX-induced cardioprotection. Conclusions DEX pretreatment protects against myocardial I/R by inhibiting cardiac HMGB1 production and activating the cholinergic anti-inflammatory pathway.

Melatonin (N-acetyl-5-methoxytryptamine) is a pleiotropic signaling molecule that plays important roles in plant growth, development and stress responses. Alfalfa (Medicago sativa L.) is an important and widely cultivated leguminous forage crop with high biomass yield and rich nutritional value. The effects of exogenous melatonin content regulation on alfalfa stress tolerance have been investigated in recent years. Here, we isolated and introduced the MsASMT1 (N-acetylserotonin methyltransferase) gene into alfalfa, which significantly improved the endogenous melatonin content. Compared with wildtype (WT) plants, MsASMT1 overexpression (OE-MsASMT1) plants exhibited a series of phenotypic changes, including vigorous growth, increased plant height, enlarged leaves and robust stems with increased cell sizes, cell numbers and vascular bundles, as well as more branches. We also found that the flavonoid content and lignin composition of syringyl to guaiacyl ratio (S/G) were decreased and the cellulose content was increased in OE-MsASMT1 transgenic alfalfa. Further transcriptomic and metabolomic exploration revealed that a large group of genes in phenylalanine pathway related to flavonoids and lignin biosynthesis were significantly altered, accompanied by significantly reduced concentrations of the glycosides of quercetin, kaempferol, formononetin and biochanin in OE-MsASMT1 transgenic alfalfa. Our study first uncovers the effects of endogenous melatonin on alfalfa growth and metabolism. This report provides insights into the regulation effects of melatonin on plant growth and phenylalanine metabolism, especially flavonoids and lignin biosynthesis.

Air pollution can increase the morbidity and mortality of cardiovascular and cerebrovascular diseases, but there are few related studies in counties and cities with serious pollution in China. China is at a critical stage of environmental pollution control. Assessing the health impact of PM2.5 (particulate matter with a diameter equal or lower than 2.5 micrometers) on the death toll from cardiovascular and cerebrovascular diseases in heavily polluted counties and cities is of great importance to the formulation of air defense policies related to PM 2.5. Generalized additive models (GAMs) were used to analyze the effects of PM2.5 exposure on the death toll of circulatory system diseases in 16 districts, counties and cities in Shijiazhuang from 2014 to 2016 after controlling the long-term trend of the time series, seasonal effects, holiday effects, air temperature, relative humidity and other factors. The average PM2.5 concentration was 121.2 ± 96.6 μg/m3; during the corresponding period, the daily mean mortality of circulatory system diseases in Shijiazhuang was 4.6 ± 4.7. With the increase of PM2.5 by 10 μg/m3, the risk of total death from circulatory system diseases with a lag of two days (lag02) increased by 3.3‰ (95% confidence interval (CI): 1.0025, 1.0041). The relative risk (RR) of the effect of PM2.5 exposure on the death toll of the circulatory system in Shijiazhuang is consistent with the spatial distribution of the PM2.5 concentration and the mortality of circulatory system diseases: the RR of the eastern plain with heavy pollution and a relatively dense population is high, while the RR of the western mountainous area with relatively light pollution and a relatively sparse population is low. For every 10-μg/m3 increase of PM2.5, the risk of the increasing death toll from circulatory system diseases in Luancheng of the eastern plain is the highest at 11.9‰ (95% CI: 1.0071, 1.0168), while the RR of Pingshan of the western mountainous area is the lowest at 2.1‰ (95% CI: 0.9981, 1.0062). Conclusions: Based on the epidemiological analysis and GAMs model, after controlling for other confounding factors, PM2.5 exposure increased the death risk of the circulatory system in Shijiazhuang, and the risk is higher in heavily polluted plain areas. It provides a scientific basis for formulating scientific air pollution prevention and control policies and provides a reference for improving the prevention awareness of sensitive groups.

Using the chronic obstructive pulmonary disease (COPD) medical records from January 1st to December 31st of 2013 and the Meteorological observation data, the air pollution data in the same time periods, generalized additive models were used to quantitatively analyze the relationship between COPD hospitalizations and temperature with controlling the confounding effects of time trend, meteorological factors and air pollution index (AQI). Results showed: variable temperature in 24 h (BT), 3d lagged minimum temperature (Tm3) and 5d lagged diurnal maximum temperature and minimum temperature range (Tc5) have different effects on COPD hospitalizations. When BT is between −4.4˚C and −0.7˚C, the relative risk (RR) increases to 1.0207 (95% CI: 1.0074 -1.0342）with every 1˚C increase in BT; when Tm3 is between −3.6˚C and 3.2˚C, the relative risk (RR) increases to 1.0118 (95% CI: 1.0015 -1.0222） with every 1˚C increase in Tm3, and when Tm3 is greater than 20.5˚C, the relative risk (RR) increases to 1.0069 (95% CI: 1.0005 -1.0133) with every 1˚C increase in Tm3; when Tc5 is between 0.9˚C and 8.6˚C, if the Tc5 increases 1˚C, the relative risk (RR) increases to 1.0125 (95% CI: 1.0066 -1.0185. There are different effects for weather in different seasons on COPD hospitalizations: in autumn and winter, it is mainly of little BT and heavy air pollution weather; in spring, the large Tc5 weather is a main feature, and in summer, it's mainly of high temperature and low pressure weather. The results help to provide some guidance on COPD forecasting services.