Objective To develop a pressure swing adsorption oxygen generating device that is workable at altitudes of 0 to 7000 meters.Methods The three-bed molecular sieve oxygen production process was adopted.The switching time of air circuit solenoid valve and the rotation speed of the compression pump were taken as controllable variables.The performance of the oxygen generating device was tested in a normal atmospheric environment and a low-pressure environment corresponding to altitudes of 0 to 7000 meters.The optimal values of controllable oxygen generating parameters corresponding to 10 low-pressure environments(89.9,79.7,69.7,65.0,62.0,57.7,53.8,47.6,43.0,41.0 kPa)were obtained.Results The oxygen concentration could reach 94％,oxygen flow rate was 9 L/min and oxygen outlet pressure stood at 44 kPa in a normal atmospheric environment(altitude 416 meters),compared with 94％,6.3 L/min and 30 kPa in a low-pressure environment of 41 kPa(altitude 7000 meters).Conclusion The oxygen generating device can meet the oxygen needs of two persons within the altitude range of 0 to 7000 meters.

Objective:To construct a prognostic predictive model for patients with moderate to severe traumatic brain injury (msTBI) based on regional cerebral oxygen saturation (rScO 2) and transcranial Doppler ultrasound (TCD) monitoring parameters and validate its effectiveness. Methods:A retrospective cohort study was conducted to analyze the clinical data of 161 patients with msTBI who were treated at Henan Provincial People′s Hospital from January 2021 to December 2022, including 104 males and 57 females, aged 19-76 years [(53.1±12.8)years]. Glasgow coma scale (GCS) score was 3-12 points [(7.0±1.9)points]. Both rScO 2 and TCD monitoring were performed. Based on the results of prognostic evaluation of patients with the modified Rankin scale (mRS) score at 90 days after discharge, the patients were divided into good prognosis group (mRS score≤3 points, n=88) and poor prognosis group (mRS score of 4-6 points, n=73). The following data of the two groups were collected: the general data, clinical data, rScO 2 monitoring parameters and TCD monitoring parameters. Univariate analysis was employed to compare the differences in the relevant prognostic indicators. Multivariate Logistic stepwise regression analysis was conducted to determine the predictors of poor prognostic outcomes in msTBI patients and regression equations were constructed. A nomogram predictive model based on regression equations was drawn with R language. The discriminability of the model was evaluated by drawing the receiver operating characteristic (ROC) curve, to calculate the area under the curve (AUC), sensitivity, specificity, and Jordan index of the model, and measuring the consistency index (C index). Hosmer-Lemeshow (H-L) goodness of fit test was conducted to evaluate the fit of the model, and the calibration curve was used to evaluate the calibration degree of the model. Decision curve analysis (DCA) was employed to evaluate the clinical benefit and applicability of the model. Results:There were significant differences between the two groups in the clinical data (cerebral hernia formation, GCS on admission, acute physiology and chronic health evaluation II (APACHE II) score on admission, Rotterdam CT score on admission, oxygenation index on admission, mean arterial pressure on admission), rScO 2 monitoring parameters (mean rScO 2, maximum rScO 2, rScO 2 variability), TCD monitoring parameters [peak systolic blood flow velocity (Vs), average blood flow velocity (Vm), pulse index (PI)] ( P<0.05 or 0.01). The results of multivariate Logistic stepwise regression analysis showed that cerebral hernia formation ( OR=9.28, 95% CI 3.40, 25.33, P<0.01), Rotterdam CT score on admission ( OR=1.92, 95% CI 1.32, 2.78, P<0.01), rScO 2 variability ( OR=4.66, 95% CI 1.74, 12.43, P<0.01), Vs ( OR=0.66, 95% CI 0.61, 0.75, P<0.01) and PI ( OR=20.07, 95% CI 4.17, 16.50, P<0.01) were predictive factors for poor prognosis in patients with msTBI. The regression equation was constructed with the forementioned 5 variables: Logit [ P/(1- P)]=2.23×"brain hernia formation"+0.65×"Rotterdam CT score on admission"+1.54×"rScO 2 variability"-0.42×"Vs"+3.00×"PI"-6.75. The AUC of prognostic predictive model of msTBI patients was 0.90 (95% CI 0.85, 0.95), with the sensitivity and specificity of 86.3% and 78.4%, Youden index of 0.65 and C index of 0.90. H-L goodness of fit test showed that the calibration degree of the predictive model was accurate ( χ2 =12.58, P>0.05). The average absolute error of the calibration curve was 0.025, showing that the calibration of the model was good. DCA results showed that this model had higher net return rate than the reference model within the probability range of risk threshold (20%-100%), with good clinical application value in evaluating the risk of poor prognosis of msTBI patients. Conclusion:The model constructed based on the combination of rScO 2 and TCD monitoring parameters (rScO 2 variability, Vs and PI) with multiple clinical indicators (cerebral hernia formation and Rotterdam CT score on admission) has good predictive performance for the prognosis of msTBI.

Objective To investigate the efficacy of Saccharomyces boulardii combined with ursodeoxycholic acid in the treating rectal ulcerative colitis (UC) and its influence on intestinal mucosal barrier function. Methods A total of 88 patients with rectal UC were randomly divided into observation group and control group, with 44 cases in each group. The scores of main symptoms (abdominal pain, diarrhea, purulent stool), score of the Inflammatory Bowel Disease Questionnaire (IBDQ), levels of inflammatory factor indicators [interleukin-6 (IL-6), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α)] and levels of intestinal mucosal barrier function indicators [the ratio of urinary lactolic acid to mannitol (L/M), serum D-lactic acid (D-LA), serum diamine oxidase (DAO), and serum lipopolysaccharide (LPS)] were compared between the two groups before and after treatment. The incidence of adverse reactions were compared between two groups. Results After treatment, the scores of abdominal pain, diarrhea and purulent stool in both groups were significantly lower than those before treatment, while the IBDQ score was significantly higher than that before treatment, and the scores of abdominal pain, diarrhea and purulent stool in the observation group were significantly lower than those in the control group, while the IBDQ score was significantly higher than that in the control group (P < 0.05). After treatment, the levels of serum D-LA, DAO, LPS and urinary L/M in both groups reduced significantly, and the levels of these indicators in the observation group were significantly lower than those in the control group (P < 0.05). After treatment, the levels of serum IL-6, TNF-α and IL-1β in both groups reduced significantly, and the levels of these indicators in the observation group were significantly lower than those in the control group (P < 0.05). The total effective rate inthe observation group was 86.36%, which was significantly higher than 68.18% in the control group (P < 0.05). There were no significant differences in incidence rates of adverse reactions such as lower abdominal pain, allergies and refractory constipation between two groups (P>0.05). Conclusion Saccharomyces boulardii combined with ursodeoxycholic acid is effective in the treatment of patients with rectal UC, which can effectively improve symptoms such as abdominal pain, diarrhea and purulent stool, inhibit the inflammatory response of the body, and alleviate damage to the intestinal mucosal barrier.

Post-stroke cognitive impairment (PSCI), one of the important complications of stroke, seriously affects the quality of life of these patients. PSCI is an important cause of disease burden of stroke. In recent years, more and more evidences show that blood biomarkers are of great significance in PSCI diagnosis, and the detection of blood biomarkers is relatively simple and more suitable for clinical application. Therefore, this paper sorts out the values of 5 blood biomarkers, nerve injury marker, metabolic biomarker, inflammatory biomarker, oxidative stress marker and other biomarker, in diagnosing PSCI, to provide references for early diagnosis and intervention of PSCI.

L-theanine has been shown to have a therapeutic effect on depression.However,whether L-theanine has an excellent preventive effect on depression in children and adolescents and what its mechanism is have not been well explained.Given the complexity of the pathogenesis of depression,this study investigated the preventive effect and mechanism of L-theanine on depression in juvenile rats by combining serum and hippocampal metabolomic strategies.Behavioral tests,hippocampal tissue sections,and serum and hippocampal biochemical indexes were studied,and the results confirmed the preventive effect of L-theanine.Untargeted reversed-phase liquid chromatography-quadrupole-time-of-flight mass spec-trometry and targeted hydrophilic interaction liquid chromatography-triple quadrupole mass spec-trometry were developed to analyze the metabolism changes in the serum and hippocampus to screen for potential biomarkers related to L-theanine treatment.The results suggested that 28 abnormal me-tabolites in the serum and hippocampus that were considered as potential biomarkers returned to near-normal levels after L-theanine administration.These biomarkers were involved in various metabolic pathways,mainly including amino acid metabolism and lipid metabolism.The levels of amino acids and neurotransmitters in the phenylalanine,tryptophan,and glutamic acid pathways were significantly reduced after L-theanine administration compared with chronic unpredictable mild stress-induced rats.In summary,L-theanine had a significant preventive effect on depression and achieved its preventive results on depression by regulating various aspects of the body,such as amino acids,lipids,and inflammation.This research systematically analyzed the mechanism of L-theanine in preventing depression and laid the foundation for applying L-theanine to prevent depression in children and adolescents.

Objective To construct a Nomogram model that can accurately predict early death of metastatic colon cancer (mCC). Methods A total of 6 669 patients from the SEER database were identified using inclusion and exclusion criteria. Multivariate logistic regression was used to identify risk factors for early mortality and to construct a Nomogram. The predictive performance of the Nomogram was evaluated by C-index, calibration curve, and decision curve analysis (DCA). Results Primary tumor location, differentiation grade, T stage, M stage, bone metastases, brain metastases, CEA, tumor size, age and marital status were independent factors for early death in patients with mCC. A Nomogram was constructed based on these variables. The C-index and the calibration curve of the Nomogram showed the good predictive ability of the nomogram. DCA showed that the Nomogram had a superior clinical net benefit in predicting early death compared with TNM stage. Conclusion The developed Nomogram has good predictive ability and can help guide clinicians to identify patients with high-risk mCC for individualized diagnosis and treatment.

Objective:To investigate the short-term and medium-term changes of the left ventricular ejection fraction (LVEF) and the predictive value of relevant electrocardiogram (ECG) indexes in children with dilated cardiomyopathy (DCM) complicated with complete left bundle branch block (CLBBB).Methods:Children clinically diagnosed with DCM in the Department of Heart Center, Women and Children′s Hospital, Qingdao University and Beijing Anzhen Hospital, Capital Medical University between November 2011 and August 2020 were retrospectively recruited.According to the combination of CLBBB, they were divided into CLBBB group and non-CLBBB group.Echocardiogram and ECG were regularly performed.Short-term and medium-term changes of LVEF based on the 1-5-year follow-up data were compared between groups.COX proportional hazards model and Kaplan-Meier multiplicative limit method were used to analyze the predictive value of ECG indexes of LVEF changes in children with DCM combined with CLBBB.Results:Ninety-four children with DCM were enrolled, including 35 cases in CLBBB group and 59 cases in non-CLBBB group.There was no difference in baseline LVEF between groups.However, significant differences were found in QRS duration, corre-cted QT interval(QTc), R peak time in lead V 5 (T V5R) and QRS notching or slurring between groups ( P<0.05). LVEF of all children showed an upward trend within one year after onset, while the Z value of eft ventricular end diastolic diameter(LVEDd) showed a downward trend, and the two indexes tended to be stable within 1 - 5 years.The Z value of LVEDd in CLBBB group was significantly higher than that of non-CLBBB group, while LVEF was significantly lower (all P<0.05). The mean LVEF of CLBBB group slightly fluctuated around 50%, that of LVEF in non-CLBBB group was 60%.The multivariate COX regression analysis showed that QRS duration ( HR=0.979; 95% CI: 0.960-0.999, P<0.05) and QTc ( HR=0.988; 95% CI: 0.979-0.998, P<0.05) were independent predictors of LVEF recovery in children with DCM.Kaplan-Meier method showed a significant difference of LVEF normalization between DCM children with different QRS durations ( P<0.05), which was also detected in those with QTc interval ( P<0.05). Conclusions:LVEF of children with DCM combined with CLBBB increases in the short term after standard treatment, and then being stable.CLBBB can affect the recovery of left ventricular systolic function in children with DCM.Moreover, QRS duration and QTc interval are independent predictors of LVEF recovery in DCM children.

Objective:To investigate the value of metagenomic next-generation sequencing (mNGS) in central nervous system infection (CNSI) of critically ill patients from Neurosurgery.Methods:A prospective study was conducted. From October 2019 to April 2021, 52 patients with highly suspected CNSI in the Department of Neurosurgical Intensive Care Unit (NICU) of our hospital were chosen. The collected cerebrospinal fluid (CSF) samples were simultaneously performed mNGS and traditional culture; the clinical diagnosis of CNSI was taken as the standard, and the sensitivity, specificity, positive predictive value, negative predictive value, and time from sample collection to result feedback of these two methods were compared. Receiver operating characteristic (ROC) curve was used to analyze the diagnostic values of mNGS and traditional culture in CNSI.Results:Eventually, 25 patients with CNSI were clinically confirmed; 23 were with positive mNGS, including 16 with bacterial infection, 4 with viral infection, 1 with fungal infection, and 2 with mixed infection (1 with bacteria+virus+fungus, 1 with bacteria+virus); 8 were with positive traditional culture, all of which were bacterial infections. The sensitivity, specificity, positive predictive value, and negative predictive value of mNGS were 92.0%, 85.2%, 85.2%, and 92.0%, respectively; those of traditional culture were 32.0%, 100.0%, 100.0%, and 61.4%, respectively; the time from sample collection to result feedback of mNGS and traditional culture was (31.77±5.23) h and (101.83±9.15) h, respectively, with significant difference ( P<0.05). ROC curve showed that the area under the curve (AUC) of mNGS for diagnosis of CNSI was 0.886 ( 95%CI: 0.786-0.986, P<0.001); the AUC of traditional culture for diagnosis of CNSI was 0.660 ( 95%CI: 0.508-0.812, P=0.002). Conclusion:For patients with CNSI from NICU, mNGS has good diagnostic efficacy and application value and can effectively compensate for the lack of traditional cerebrospinal fluid culture.

Alzheimer's disease (AD) is the most common form of dementia in the elderly, and there is no specific treatment to stop or reverse its progression. Mild cognitive impairment (MCI) is an important entry point for early diagnosis and prevention of AD. More and more studies have explored the risk factors and biomarkers for conversion from MCI to AD, and a series of risk prediction models have been established. This article analyzes and summarizes the different predictors and risk prediction models so as to provide basis for early identifying the high-risk group of AD, managing the controllable risk factors, and providing references for the selection and improvement of these models.

Objective:Donor cytomegalovirus (CMV) serological negative status may have an adverse effect on the outcome of allogeneic hematopoietic stem cell transplantation (allo-HSCT), while there is inadequate data for Chinese people. This study is to explore the impact of donor CMV serological status on the outcome of CMV seropositive patients receiving allo-HSCT.Methods:Our study retrospectively analyzed 16 CMV seropositive patients with hematological malignancies receiving allogeneic grafts from CMV seronegative donors (antibody IgG negative) at Peking University People′s Hospital from March 2013 to March 2020, which was defined as D -/R + group. The other 64 CMV seropositive patients receiving grafts from CMV seropositive donors at the same period of time were selected as matched controls through a propensity score with 1∶4 depending on age, disease state and donor-recipient relationship (D +/R + group). Results:Patients in D -/R + group developed CMV DNAemia later than patients in the D +/R + group (+37 days vs. +31 days after allo-HSCT, P=0.011), but the duration of CMV DNAemia in D -/R + group was longer than that of D +/R + group (99 days vs. 34 days, P=0.012). The rate of CMV reactivation 4 times or more in D -/R + group was 4/16, significantly higher than that of D +/R + group (4.7%, 3/64, P=0.01). The incidences of refractory CMV DNAemia (14/16 vs. 56.3%, P=0.021) and CMV disease (4/16 vs. 4.7%, P=0.01) in D -/R + group were both higher than those in D +/R + group. In addition, the application of CMV-CTL as the second-line antiviral treatment in D -/R + group was more than that in D +/R + group. Univariate analysis and multivariate analysis suggested that CMV serological negativity is an independent risk factor for refractory CMV DNAemia and the duration of CMV infection. The cumulative incidence of aGVHDⅡ-Ⅳ, cGVHD, 3-year probability of NRM, overall survival, and the cumulative incidence of relapse were all comparable in two groups. Conclusions:Although there is no significant effect on OS and NRM, the incidence of refractory CMV DNAemia, the frequency of virus reactivation, and the development of CMV disease in D -/R + group are higher than those in controls. Therefore, CMV seropositive donors are preferred for CMV seropositive patients.