Objective To observe the effects of intermittent 45? head-uptilt on endothelin(ET-1) expression and morphological changes of femoral and carotid arteries in rabbits induced by 21 d simulated weightlessness.Method Twenty-four healthy male rabbits were randomly divided into control group,simulated weightlessness group and countermeasure group,8 rabbits in each group.The simulated weightlessness group kept head-down tilt for 21 d.The countermeasure group was exposed to 45? head-up tilt for 2 h every day during 21 d head-down tilt.After 21 d experiment,structure of femoral artery and carotid artery were studied and ET-1 expression was tested by immunohistochemical method.Result Detachment of endothelial cells in femoral artery,necrosis of smooth muscle cells and decreased ET-1 expression were found in animals in the simulated weightlessness group,and the vessel wall became thinner.While hyperplasia of endothelial cells and thickened internal elastic lamina of the carotid artery were also observed.No significant changes were observed in femoral artery and carotid artery in animals of the countermeasure group.ET-1 expression decreased in femoral artery but increased in carotid artery in animals of the simulated weightlessness group,but no significant change was found in both femoral and carotid arteries in animals of the countermeasure group as compared with those in the control group.Conclusion Twenty-one days simulated weightlessness may induce an atrophic change and decreased ET-1 expression in femoral artery,and hyperplastic change and increased ET-1 expression in carotid artery in rabbits.Two-hour 45? head-up tilt every day may partly counteract the change in femoral artery and carotid artery induced by simulated weightlessness.

Objective The investigation of diatom species composition and database of diatom scanning electron microscope in the Pearl River of Guangdong province. Methods Using the Lefort aqua regia digestion 19 different sampling sites (6 in the West River, 9 in the North River, and 4 in the East River) were sampled by us in June and September 2012.Water samples from each sampling site was digested and then observed by scanning electron microscopy. The diatom genera found in samples were recorded. Results 21 diatom genera, including Achnanthes, Cocconeis, Coscinodiscus, Cyclotella, Cymatopleura, Cymbella, Diatoma, Diploneis, Gomphonema, Gyrosigma, Hantzschia, Melosira, Navicula, Nitzschia, Pinnularia, Rhoicosphenia, Stauroneis, Stephanodisus, Surirella, Synedra, Tabellaria, were found in all the samples. Conclusion It is helpful to legal medical expert by using database of diatom scanning electron microscope in the Pearl River of Guangdong province. As hundreds of diatoms pictures were taken by SEM, it would be a valuable reference of diatoms identification for forensic experts as well as diagnosis of drowning place.

OBJECTIVE To construct and evaluate nomogram prediction model for refractory chemotherapy-induced nausea and vomiting （CINV）. METHODS The data of malignant tumor patients who received chemotherapy at the Third People’s Hospital of Zhengzhou from January 2017 to December 2023 were collected. These patients were categorized into the occurrence group and the non-occurrence group according to the occurrence of refractory CINV. Multivariate Logistic regression analysis was employed to screen predictive factors for refractory CINV and constructing a nomogram prediction model. Model performance was assessed via receiver operating characteristic curve analysis. Model calibration was evaluated using Bootstrap resampling. Decision curve analysis （DCA） was used to determine the clinical net benefit of three strategies under different risk thresholds. Clinical impact curves were utilized to assess the clinical value of the model at different risk thresholds. Shapley additive explanations （SHAP） analysis was performed to evaluate individual factor contributions to the predictive model. RESULTS A total of 388 patients were included， with 219 experiencing refractory CINV. Multivariate Logistic regression identified 11 predictive factors for refractory CINV， including gastrointestinal disease history， anticipated nausea and vomiting， chemotherapy-induced emetic risk classification， and electrolyte levels， etc. The model’s area under the curve was 0.80 [95% confidence interval （0.76， 0.84）]， with a mean error of 0.036. DCA demonstrated the prediction model had higher clinical net benefit when the risk threshold was between 0.05 and 0.85. SHAP analysis revealed the top three predictive factors as gastrointestinal disease history （0.924）， chemotherapy- induced emetic risk classification （0.866）， and electrolyte levels （0.581）. CONCLUSIONS Eleven factors， including gastrointestinal disease history， anticipated nausea and vomiting， chemotherapy-induced emetic risk classification， and electrolyte levels， are identified as predictors of refractory CINV. The model based on these factors has good predictive ability， which can be used to predict the risk of refractory CINV.

OBJECTIVE To explore the influence of surgical history on chemotherapy -induced nausea and vomiting （CINV）. METHODS A retrospective case -control study was adopted ，with 824 patients undergoing chemotherapy as the object . A total of 27 items were collected ，including demographic data ，medical history data ，pre-chemotherapy data ，and chemotherapy treatment status. Logistic regression model was used to analyze the relationship between the history of surgery and the risk of CINV . The multiple models were constructed to correct potential confounding factors ，and subgroup analysis was performed on patients with surgical history . RESULTS The incidence of CINV was higher in patients with surgical history . The statistical result before adjustment was [OR＝1.72，95%CI（1.31，2.28），P＜0.001]；after adjusting potential confounding factors ，the statistical result was [OR＝1.78，95% CI（1.28，2.48），P＝0.001]. In the subgroup analysis ，the time between surgery and chemotherapy was different ， and the impact of surgical history on CINV was different ，and the results were statistically significant （P＝0.027）. The risk of CINV showed decreasing trend with the time ，and the results were statistically significant （P for trend ≤0.050）. Compared with patients who had not undergone surgery ，patients who had undergone surgery within one year had a higher risk of CINV [OR＝ 2.33，95%CI（1.52，3.59），P＜0.001]. CONCLUSIONS Patients with surgical history are more prone to CINV ，and the risk of CINV shows a downward trend in the length of time from surgery .