Regio- and Enantioselective Nickel-Catalyzed Ipso- and Remote Hydroamination Utilizing Organic Azides as Amino Sources for the Synthesis of Primary Amines.

Primary amines serve as key synthetic precursors to most other N-containing compounds, which are important in organic and medicinal chemistry. Herein, we present a NiH-catalyzed mild ipso- and remote hydroamination technique that utilizes organic azides as deprotectable primary amine sources. This strategy offers a highly flexible platform for the efficient construction of α-chiral branched primary amines, as well as linear primary amines.

Effect of age on postoperative 24-hour moderate-to-severe pain after radical resection of lung cancer-specific pain in the post-anaesthesia care unit: a single-centre retrospective cohort study.

OBJECTIVES: To explore the relationship between age and postoperative 24-hour moderate-to-severe pain after radical resection of lung cancer and the specific effect of moderate-to-severe pain in the post-anaesthesia care unit (PACU) on this relationship. DESIGN: Retrospective cohort study. SETTING: Single medical centre. PARTICIPANTS: Patients ≥18 years having radical resection of lung cancer between 2018 and 2020. MEASUREMENTS: Postoperative 24-hour moderate-to-severe pain. RESULTS: A total of 3764 patients were included in the analysis. The incidence of postoperative 24-hour moderate-to-severe pain was 28.3%. Age had a significant effect on the prediction model of postoperative 24-hour moderate-to-severe pain. Among the whole population and those without moderate-to-severe pain in the PACU, those who were younger than 58.5 years were prone to experience moderate-to-severe pain 24 hours after surgery, and in patients with moderate-to-severe pain in the PACU, the age threshold was 62.5 years. CONCLUSION: For patients who underwent elective radical resection for lung cancer, age was related to postoperative 24-hour moderate-to-severe pain, and moderate-to-severe pain in the PACU had a specific effect on this relationship. Patients among the whole population and those patients without moderate-to-severe pain in the PACU were more likely to experience postoperative 24-hour moderate-to-severe pain when they were younger than 58.5 years old, and in patients with moderate-to-severe pain in the PACU, the age threshold was 62.5 years old.

Analysis of the diagnostic value of CT radiomics models in differentiating GIST and other mesenchymal tumors.

OBJECTIVE: To analyze the diagnostic value of computed tomography (CT) radiomics models in differentiating gastrointestinal stromal tumors (GIST) and other mesenchymal tumors. MATERIAL AND METHODS: A retrospective analysis of clinical data from 153 patients with pathologically confirmed gastrointestinal mesenchymal tumors treated in our hospital from July 2019 to March 2024 was conducted, including 107 cases of GIST, 18 cases of leiomyoma, and 28 cases of schwannoma. LASSO regression was used for feature selection. Logistic regression and Random Forest (RF) models were established based on selected features using machine learning algorithms, with the dataset divided into training (107 cases) and validation sets (46 cases) at a 7:3 ratio. The diagnostic performance of the models was evaluated using receiver operating characteristic (ROC) curves. RESULTS: In the training set, there were significant differences between GIST and non-GIST in terms of enhancement degree, age, maximum diameter, and tumor location distribution (P<0.05). A total of 180 radiomics features were extracted using A.K software. LASSO regression reduced the high-dimensional data to 13 radiomics features. Logistic regression and RF models were established based on these 13 features. The AUC for the Logistic regression model was 0.753 in the training set and 0.582 in the validation set, while the AUC for the RF model was 0.941 in the training set and 0.746 in the validation set. The RF model showed higher diagnostic performance than the Logistic regression model (P<0.05). Decision curve analysis showed that the net benefit of the RF model in differentiating GIST was superior to classifying all patients as either GIST or non-GIST and also superior to the Logistic regression model within a probability threshold range of 20%-90%. CONCLUSION: The machine learning models based on radiomics features have good diagnostic value in predicting the pathological classification of GIST and other mesenchymal tumors, with the RF model showing superior diagnostic value compared to the Logistic regression model.

BOC targets SMO to regulate the Hedgehog pathway and promote proliferation, migration, and invasion of glioma cells.

The purpose of this study was to investigate the effects of BOC on glioblastoma cells and its underlying mechanisms. In vitro, BOC-knockdown was performed in glioma cell lines. CCK-8 and Transwell were used to assess the impact of BOC on the viability, invasion, and migration of gliobma cells. RNA-seq technology was employed to analyze the differential gene expression between BOC-knockdown glioma cells and the control group, and qRT-PCR was used to validate the expression of downstream differential genes. SMO-overexpression was performed to investigate the effects of SMO on glioma cells. A BOC-knockdown mouse subcutaneous tumor model was to verify the effects of BOC on mouse tumors. Tissue microarray technology was used to detect the expression of BOC and SMO in samples of normal human brain tissue and glioma tissue. In vitro, BOC-knockdown inhibited the viability, invasion, and migration of glioma cells, as well as downregulated the expression of downstream differential genes SMO, EGFR, HRAS, and MRAS. Conversely, SMO-overexpression upregulated the viability, invasion, and migration abilities of BOC-knockdown cells. In vivo, BOC-knockdown suppressed tumor growth in mice and downregulated the expression of downstream differential genes SMO, EGFR, HRAS, and MRAS. Tissue microarray results showed that both BOC and SMO were highly expressed in glioma tissues. BOC is aberrantly overexpressed in glioma patients and promotes glioma development. Mechanistically, BOC activates the Hedgehog (Hh) and RAS signaling pathways by upregulating the expression of SMO, EGFR, HRAS, and MRAS, thereby facilitating the Proliferation, invasion and migration of glioma cells.

pyRBDome: a comprehensive computational platform for enhancing RNA-binding proteome data.

High-throughput proteomics approaches have revolutionised the identification of RNA-binding proteins (RBPome) and RNA-binding sequences (RBDome) across organisms. Yet, the extent of noise, including false positives, associated with these methodologies, is difficult to quantify as experimental approaches for validating the results are generally low throughput. To address this, we introduce pyRBDome, a pipeline for enhancing RNA-binding proteome data in silico. It aligns the experimental results with RNA-binding site (RBS) predictions from distinct machine-learning tools and integrates high-resolution structural data when available. Its statistical evaluation of RBDome data enables quick identification of likely genuine RNA-binders in experimental datasets. Furthermore, by leveraging the pyRBDome results, we have enhanced the sensitivity and specificity of RBS detection through training new ensemble machine-learning models. pyRBDome analysis of a human RBDome dataset, compared with known structural data, revealed that although UV-cross-linked amino acids were more likely to contain predicted RBSs, they infrequently bind RNA in high-resolution structures. This discrepancy underscores the limitations of structural data as benchmarks, positioning pyRBDome as a valuable alternative for increasing confidence in RBDome datasets.

Effect of preoperative natural killer cell on postoperative pulmonary complications in patients of lung cancer - A single-center retrospective cohort study.

BACKGROUND: The effect of preoperative natural killer (NK) cell abnormalities on postoperative pulmonary complications (PPCs) after thoracoscopic radical resection of lung cancer is still unclear. The main purpose of this study was to investigate the relationship between the preoperative NK cell ratio and PPCs. METHODS: The patients who underwent thoracoscopic radical resection for lung cancer were divided into a normal group and an abnormal group according to whether the proportion of preoperative NK cells was within the reference range. The main outcome was the incidence of PPCs during postoperative hospitalization. The demographic and perioperative data were collected. Propensity score matching was used to exclude systematic bias. Univariate logistic regression was used to test the relationship between the preoperative NK cell ratio and the incidence of PPCs. The restrictive cubic spline curve was used to analyze the dose-effect relationship between the preoperative NK cell ratio and the incidence of PPCs. RESULTS: A total of 4161 patients were included. After establishing a matching cohort, 910 patients were included in the statistical analysis. The incidence of PPCs in the abnormal group was greater than that in the normal group (55.2% vs. 31.6%). The incidence of PPCs first decreased and then increased with increasing NK cell ratio. The proportion of patients with Grade 3 or higher PPCs in the normal group was lower than that in the abnormal group [108 (23.7%) vs. 223 (49%)]. The indwelling time of the thoracic drainage tube in the abnormal group was longer than that in the normal group [3 (3, 4) vs. 3 (3, 5)]. A preoperative abnormal NK cell ratio constituted a risk factor for PPCs in each subgroup. CONCLUSION: Lung cancer patients with an abnormal proportion of peripheral blood NK cells before surgery were more likely to develop PPCs, their disease degree was more severe, and they had a prolonged duration of chest tube indwelling. Compared with those with abnormally high NK cell ratios, those with abnormally low NK cell ratios had more pronounced PPCs.

A Study on the Removal of Impurity Elements Silicon and Zinc from Rubidium Chloride by Vacuum Distillation.

With the rapid development of high and new technology, rubidium and its compounds show broad application prospect and market demand with their unique characteristics. At present, the production of rubidium metal is mainly prepared by calcium thermal reduction of rubidium chloride. Rubidium metal obtained by reduction requires multi-step vacuum distillation to obtain high-purity rubidium metal. The purity of rubidium metal depends on the purity of the raw material rubidium chloride. Rubidium metal is relatively active and is easy to oxidize and explode in air. Therefore, a method combining vacuum decomposition and vacuum distillation to reduce impurity elements in rubidium chloride from raw materials is proposed in this paper. The experimental results show that under the conditions of pressure of 5-10 Pa, distillation temperature of 823 K and vacuum distillation time of 60 min, the contents of Si and Zn impurities are reduced from 1206 mg/kg and 310 mg/kg to less than 0.1 mg/kg, and the removal rates are 99.99% and 99.97%, respectively. Rubidium chloride has almost no loss, and through one-step vacuum distillation, the impurity elements silicon and zinc can be deeply removed, reducing the flammability and explosiveness, high cost, long process and other problems caused by the subsequent preparation of high-purity rubidium metal.

Controlling the graphite-like microcrystalline structure of lignin-based ultrafine carbon fibers via the design of condensed structures.

Obtaining lignin-based graphite-like microcrystallites at a relatively low carbonization temperature is still very challenging. In this work, we report a new method based on condensed structures, for regulating graphite-like microcrystalline structures via the incorporation of 4,4'-diphenylmethane diisocyanate (MDI) into the main structure of lignin. The effects of MDI on the thermal properties of lignin and the graphite-like microcrystalline structure of lignin-based ultrafine carbon fibers were extensively studied and investigated. The incorporation of MDI decreased the thermal stability of lignin, increased the carbon yield and enhanced the formation of graphite-like microcrystallites, which are beneficial for reducing energy consumption during the preparation of lignin-based carbon fibers. The modified lignin-based ultrafine carbon fibers (M-LCFs) demonstrated satisfactory electrochemical performance, including high specific capacitance, low charge transfer resistance, and good cycle performance. The M-LCFs-3/2 electrode had a specific capacitance of 241.3 F g-1 at a current density of 0.5 A g-1, and a residual ratio of 90.2 % after 2000 charge and discharge cycles. This study provides a new approach to control the graphite-like microcrystalline structure and electrochemical performance while also optimizing the temperature.

How work stress influence turnover intention among Chinese local undergraduate university teachers: the mediating effect of job burnout and the moderating effect of self-efficacy.

Background: Turnover intention is one of the common disturbances that affect the career development and management of university teachers. With an aim to solve this thorny issue, the study examined the associations between turnover intention and work stress among local undergraduate university teachers in China. Methods: A questionnaire survey was carried out on 7,565 local university teachers. Initially, confirmatory factor analysis was employed to validate the reliability and validity of the scale. Subsequently, descriptive statistics and correlation analyses were conducted. Following this, a latent moderated structural equation (LMS) was used to explore the relationship among work stress, job burnout, self-efficacy, and turnover intention. Moreover, the bias-corrected Bootstrap method was applied to further examine the mediating effects, moderating effects, and moderated mediating effects in the model. Results: The hypothesized moderated mediation model was verified significant. Work stress directly and positively predicted job burnout and turnover intention, with job burnout serving a partial mediating role between work stress and turnover intention. Additionally, self-efficacy negatively moderated the direct impact of work stress on job burnout, as well as the mediating effect of job burnout. As the self-efficacy of university teachers increased, the direct effect of work stress on job burnout and the mediating effect of job burnout decreased. Conclusion: This study expanded the research on the antecedent variables of university teachers' turnover intention and revealed the individual contingency mechanism by which work stress affected turnover intention: the negative moderating effect of self-efficacy. Work stress induced university teachers' turnover intention, and this phenomenon was more obvious for faculties with low self-efficacy. Administrators of local undergraduate universities need to rationalize the allocation of teachers' job responsibilities and pay attention to the negative consequences of work stress in order to reduce turnover intentions. Particular attention should be paid to enhance teachers' self-efficacy. The findings of this study can provide in-depth recommendations for university faculty management and policy making, which can help shape a working atmosphere more conducive to teaching and research, thus enhancing the overall quality and competitiveness of faculty members within universities.

Developing Air-Stable n-Type SWCNT-Based Composites with High Thermoelectric and Robust Mechanical Properties for Wearable Electronics.

Flexible organic thermoelectric generators are gaining prominence in wearable electronics, leveraging body heat as an energy source. Their advancement is hindered by the scarcity of air-stable n-type organic materials with robust mechanical properties. This study introduces two new polymers (HDCN4 and HDCN8), created through polycondensation of paraformaldehyde and diamine-terminated poly(ethylene glycol) (PEGDA) with molecular weights of 4000 and 8000 g/mol into single-walled carbon nanotubes (SWCNTs). The resulting HDCN4/SWCNT and HDCN8/SWCNT composites show impressive power factors of 225.9 and 108.2 µW m-1 K-2, respectively, and maintain over 90% in air for over four months without encapsulation. The HDCN4/SWCNT composite also demonstrates significant tensile strength (33.2 MPa) and flexibility (up to 10% strain), which is currently the best mechanically n-type thermoelectric material with such a high power factor reported in the literature. A thermoelectric device based on HDCN4/SWCNT generates 4.2 µW of power with a 50 K temperature difference. Additionally, when used in wearable temperature sensors, these devices exhibit high mechanical reliability and a temperature resolution of 0.1 K. This research presents a viable method to produce air-stable n-type thermoelectric materials with excellent performance and mechanical properties.

Effect of dexmedetomidine on postoperative nausea and vomiting in female patients undergoing radical thoracoscopic lung cancer resection.

Introduction: Postoperative nausea and vomiting (PONV) is a prevalent postsurgical complication. The objective of our study was to compare the effect of different doses of dexmedetomidine on PONV in female patients undergoing radical thoracoscopic lung cancer resection. Methods: A total of 164 female patients undergoing elective thoracoscopic radical lung cancer surgery were enrolled and assigned to one of four groups. Patients received 0.2 µg/kg/h, 0.4 µg/kg/h, 0.8 µg/kg/h dexmedetomidine and normal saline in the Dex1, Dex2, Dex3 and Control groups, respectively. The primary outcome was the incidence of PONV during 48 h postoperatively. The second outcomes included the incidence of PONV and postoperative vomiting (POV) at four time points postoperatively (T1: PACU retention period; T2: PACU discharge to postoperative 12 h; T3: postoperative 12 h-postoperative 24 h; T4: postoperative 24 h-postoperative 48 h), the area under the curve of PONV grade (PONVAUC), PONV grade, POV grade and other postoperative recovery indicators. Results: The incidence of PONV differed among the four groups. The Dex2 group (29.27%) was lower than that in the Dex1 group (61.90%) and Control group (72.50%). The incidence of PONV at T2 in the Dex1 group (11.90%) and Dex2 group (9.76%) was lower than that in the Control group (42.50%). The incidence of PONV at T3 in the Dex2 group (29.27%) was lower than that in the Dex1 group (61.90%) and Control group (62.50%). The PONVAUC was lower in the Dex2 group than in the Control group. The incidence of POV at T3 in the Dex2 and Dex3 groups was lower than that in the Control group. The consumption of remifentanil, norepinephrine, PACU dwell time, VAS scores, postoperative PCA press frequency, and the time for the first postoperative oral intake were different among the four groups. The regression model shows that the Dex2 group is a protective factor for PONV. Conclusion: Dexmedetomidine can reduce the incidence of PONV and accelerate postoperative recovery in female patients undergoing radical thoracoscopic lung cancer resection. Compared with the other two dosages, 0.4 µg/kg/h dexmedetomidine is preferable. Clinical Trial Registration: chictr.org.cn, identifier ChiCTR2300071831.

A patient with a pulmonary hernia and chance fracture of the thoracic vertebra following a fall: A case report and literature review.

INTRODUCTION AND IMPORTANCE: Pulmonary hernia is a rare disease caused mostly by chest trauma. Patients often present with non-specific signs and symptoms. Currently, there is no unified approach to treating it. For asymptomatic pulmonary hernias, conservative treatment has been chosen in the past. However, the increasing number of cases has shown that surgery has a more positive effect on some patients with asymptomatic pulmonary hernias. CASE PRESENTATION: A 63-year-old female patient who accidentally fell from an agricultural vehicle while doing farm work presented with back pain and lower limb paralysis. Her vital signs were stable. A chest computed tomography (CT) scan showed the patient had a pulmonary hernia, thoracic vertebra Chance fracture, rib fractures, and right hydropneumothorax. The patient received an open reduction internal fixation (ORIF) of the thoracic vertebra at the trauma emergency center. The postoperative chest CT scan showed that the pulmonary hernia had reset to the chest cavity. Subsequently, the patient got a pulmonary hernia repair at the thoracic surgery department. The patient was discharged on the 19th day after the injury. Long-term follow-up showed good recovery from the thoracic trauma. CLINICAL DISCUSSION: The patient had a pulmonary hernia combined with thoracic Chance fracture and other injuries. Surgical repair achieved satisfactory results. CONCLUSION: We lack guidelines on whether to manage pulmonary hernias surgically. Patients with asymptomatic pulmonary hernias particularly should have their long-term prognoses fully evaluated. Surgery is needed if the patient has high-risk factors and severe intercostal muscle defects.

Human umbilical cord mesenchymal stem cells-derived exosomes exert anti-inflammatory effects on osteoarthritis chondrocytes.

Inflammation of chondrocytes plays a critical role in the occurrence and development of osteoarthritis (OA). Recent evidence indicated exosomes derived from mesenchymal stem cells (MSCs-Exos) exhibit excellent anti-inflammatory ability in many troublesome inflammatory diseases including OA. In the present study, we aimed to explore the role of human umbilical cord-derived MSCs-Exos (hUC-MSCs-Exos) in treating the inflammation of chondrocytes and its related mechanisms. Ultracentrifugation was applied to isolate hUC-MSCs-Exos from the culture supernatant of hUC-MSCs. Two OA-like in vitro inflammation models of human articular chondrocytes induced with interleukin 1ß (IL-1ß) and co-incubation with macrophage utilizing transwell cell culture inserts were both used to evaluate the anti-inflammatory effects of hUC-MSCs-Exos. The mRNA sequencing of chondrocytes after treatment and microRNA (miRNA) sequencing of hUC-MSCs-Exos were detected and analyzed for possible mechanism analysis. The results of the study confirmed that hUC-MSCs-Exos had a reversed effect of IL-1ß on chondrocytes in the expression of collagen type II alpha 1 (COL2A1) and matrix metalloproteinase 13 (MMP13). The addition of hUC-MSCs-Exos to M1 macrophages in the upper chamber showed down-regulation of IL-1ß and tumor necrosis factor α (TNF-α), up-regulation of IL-10 and arginase1 (ARG1), and reversed the gene and protein expression of COL2A1 and MMP13 of the chondrocytes seeded in the lower chamber. The results of this study confirmed the anti-inflammatory effects of hUC-MSCs-Exos in the human articular chondrocytes inflammation model. hUC-MSCs-Exos may be used as a potential cell-free treatment strategy for chondrocyte inflammation in OA.

Visible light-activated prodrug system with a novel heavy-atom-free photosensitizer.

The use of light to activate prodrugs offers a promising method for the precise control of drug release, reducing drug-related side effects, and enhancing therapeutic effectiveness. We have created a novel prodrug system that utilizes a unique, heavy-atom-free photosensitizer to produce singlet oxygen, which then triggers the conversion of the prodrug into its active form. This system has been successfully demonstrated through the creation of "photo-unclick" prodrugs of paclitaxel (PTX), combretastatin A-4 (CA-4), and 10-hydroxy-7-ethylcamptothecin (SN-38). These prodrugs show decreased toxicity in the absence of light, but exhibit increased toxicity when exposed to red light.

Sex and age differences in chronic postoperative pain among patients undergoing thoracic surgery: a retrospective cohort study.

Background: The effect of sex and age on chronic post-thoracic surgical pain (CPTP) at rest and with activity remains unclear. The main purpose of this study was to investigate the relationship between the incidence of chronic postoperative pain (at rest and with activity) and sex/age differences. Methods: This was a single-center retrospective study that included adult patients who had undergone elective thoracic surgery. Patients were divided into two groups based on sex. Demographic and perioperative data were collected, including age, sex, education level, Body Mass Index (BMI), American Society of Anesthesiologists (ASA) physical status, and medical history (hypertension, diabetes mellitus). Chronic postoperative pain data were collected by telephone follow-up. Results: Among the 3,159 patients enrolled, 1,762 were male, and 1,397 were female. After creating a matched-pairs cohort, 1,856 patients were analyzed. The incidence of CPTP at rest was 14.9% among males and 17.8% among females (p = 0.090). The incidence of CPTP with activity was 28.4% among males and 35.0% among females (p = 0.002). We analyzed three different models after propensity matching to validate the stability of the prediction model between sex and CPTP, and female sex was a significant predictor of CPTP with activity 3 months after surgery. Further analysis showed that females in the 45-55-year-old age group were more prone to develop CPTP. Conclusion: Females have a higher incidence of chronic postoperative pain with activity after thoracic surgery. Females in the 45-55-year-old age group are more prone to develop CPTP than females in other age groups.

MSL1 Promotes Liver Regeneration by Driving Phase Separation of STAT3 and Histone H4 and Enhancing Their Acetylation.

Male-specific lethal 1 (MSL1) is critical for the formation of MSL histone acetyltransferase complex which acetylates histone H4 Lys16 (H4K16ac) to activate gene expression. However, the role of MSL1 in liver regeneration is poorly understood. Here, this work identifies MSL1 as a key regulator of STAT3 and histone H4 (H4) in hepatocytes. MSL1 forms condensates with STAT3 or H4 through liquid-liquid phase separation to enrich acetyl-coenzyme A (Ac-CoA), and Ac-CoA in turn enhances MSL1 condensate formation, synergetically promoting the acetylation of STAT3 K685 and H4K16, thus stimulating liver regeneration after partial hepatectomy (PH). Additionally, increasing Ac-CoA level can enhance STAT3 and H4 acetylation, thus promoting liver regeneration in aged mice. The results demonstrate that MSL1 condensate-mediated STAT3 and H4 acetylation play an important role in liver regeneration. Thus, promoting the phase separation of MSL1 and increasing Ac-CoA level may be a novel therapeutic strategy for acute liver diseases and transplantation.

Effects of preoperative current smoking on chronic postsurgical pain in thoracic surgery: a retrospective cohort study.

OBJECTIVE: This study aimed to investigate the effect of preoperative current smoking on chronic postsurgical pain in patients who underwent thoracic surgery. METHODS: A total of 5,395 patients aged over 18 years old who underwent thoracic surgery from January 2016 to March 2020 in Henan Provincial People's Hospital were enrolled. Patients were divided into two groups: the smoking group (SG group) and the nonsmoking group (NSG group). Propensity score matching was utilized to eliminate the influence of confounding factors, and a multivariable logistic regression model was established to determine the effect of preoperative current smoking on chronic postsurgical pain. The dose-response relationship between the smoking index (SI) and chronic postsurgical pain at rest was analyzed using a restricted cubic spline curve. RESULTS: In a matched cohort of 1028 patients, the incidence of chronic pain at rest was 13.2% in the smoking group and 19.0% in the nonsmoking group (P = 0.011). Three different models were used to verify the stability of the model between preoperative current smoking and chronic postsurgical pain. A regression model was established to determine the influence of different smoking indexes (SIs) on chronic postsurgical pain. The incidence of chronic pain at rest was lower in patients with SI ≥400 before thoracic surgery than in patients whose SI was less than 400. CONCLUSIONS: A relationship between the preoperative current smoking index and chronic postsurgical pain at rest was observed. The incidence of chronic postsurgical pain at rest was lower in patients whose SI was greater than 400.

Hyper non-CG methylation of expanded plant disease resistance NLR genes.

KEY MESSAGE: We explored the phylogenomics and methylomics of NLR genes in 41 plant species and found that highly duplicated plant NLR genes are hyper methylated in non-CG context.

Discontinuous low temperature stress and plant growth regulators during the germination period promote roots growth in alfalfa (Medicago sativa L.).

In high-cold regions, alfalfa is susceptible to cold damage during the seed germination. The effects of discontinuous low temperature stress and plant growth regulators (PGRs) on alfalfa were studied in response to the high day/night temperature differentials in the area. The experiments included seed germination, seedling cold tolerance and plant recovery. Variable temperatures (VT) of 0 °C/15 °C, 5 °C/20 °C and 10 °C/25 °C were set and seeds were soaked with alginate oligosaccharides (AOS), brassinolide (BR) and diethyl aminoethyl hexanoate (DA-6) during the germination period. Parameters such as seed germination and mean germination time (MGT), phenylalanine ammonia-lyase (PAL) activity and oligomeric proanthocyanidins (OPC) content of early seedlings, dry matter accumulation and root crown of the restored plants were analysed. The results showed that low variable-temperature (LVT) stress prolonged the MGT but had little inhibitory effect on germination percentage. Early seedlings adapted to LVT stress by regulating their own water and OPC content, PAL activity and other parameters. LVT induced early alfalfa seedlings to increase their underground biomass by shortening root length and increasing root diameter, and those that had accumulated more underground biomass had faster growth rates and higher total biomass when the ambient temperature rose. AOS also promoted an increase in root crown diameter and root dry weight. This research proved that LVT stress and AOS during the germination process can lead to better growth of alfalfa in high cold regions.

Relationships Between College Students' Belief in a Just World and Their Learning Satisfaction: The Chain Mediating Effects of Gratitude and Engagement.

Purpose: This paper reveals the mechanism of the influence of belief in a just world on college students' learning satisfaction, and provides reference for further improving the quality of talent training in higher education. Methods: By convenient sampling method, 131,894 college students from 348 undergraduate universities in China were investigated on the belief in a just world scale, gratitude scale, learning engagement scale and learning satisfaction scale. Then, SPSS, AMOS and other software were used to analyze the data. Results: 1) Belief in a just world, gratitude, learning engagement and learning satisfaction are positively correlated. 2) Belief in a just world can not only directly and positively predict college students' learning satisfaction, but also indirectly and positively predict college students' learning satisfaction through gratitude and learning engagement respectively. 3) Gratitude and learning engagement play a chain mediating role between belief in a just world and learning satisfaction. Conclusion: Belief in a just world positively predicts college students' learning satisfaction through gratitude and learning engagement, suggesting that colleges and universities should create a fair learning environment and enhance college students' sense of gratitude, so as to improve college students' belief in a fair world and gratitude level, thus promoting their learning engagement and finally improving their learning satisfaction.