Electrocardiac signal is one of the most important signals which is used to trigger ventricular assist device (VAD), and the delay time of VAD assistance is very important to get a satisfied result. Proper delay will give VAD relatively enough time to assist, avoiding left heart failure caused by the collision of the heart and VAD during systolic phase. This becomes much more important when the left atrium drainage is insufficient. The aim of our study is to set up an equation to calculate the delay time by RR interval. We try to set up an equation about RR and R-Ao like: R-Ao = A x (RR)n + B(A and B are constant). RR represents the RR interval and R-Ao represents the duration of the period between the peak point of QRS and the point of aortic valve closing; First, calculate RR according to weighting average method, and then, calculate the anticipant R-Ao according to the before-mentioned equation. After adjustment, R-Ao will be used as assistance delay time. R-R interval was measured in 457 selected pediatric patients who were undergiong left heart catheterization and who did not have arrhythmias. From the ECG recording during catheterization, R-R interval was measured while R-Ao was obtained from aortic pressure wave chart; Plot graphs with R-Ao as dependent variable and (RR)n as independent variable; find out correlating model and calculate the arguments A and B of R-Ao = A x (RR)n + B. The results showed that the relation between (RR)1/3 and R-Ao is the most significant, the relation coefficient is 0.733, the regress coefficient is -0.182 (P < 0.001) and the interception is 1.070. This means that R-Ao = (-0.182) (RR) 1/3 + 1.070. The likelyhood degrees of different sections differ markedly. When heart rate is less than 120 beats per min. The relation argument is about 0.733 while 0.45 when heart rate is more than 120 beats per min, Therefore, we can use the equation R-Ao = (-0.182) (RR)1/3 + 1.070 to calculate R-Ao when heart rate is less than 120 beats per min.
Adolescent ; Algorithms ; Child ; Child, Preschool ; Counterpulsation ; methods ; Electrocardiography ; Heart ; physiology ; Heart-Assist Devices ; Humans ; Signal Processing, Computer-Assisted

The ethical dilemma in scientific research exists at all stages of the scientific research activities among medical graduate students,mainly involving conflicts of interest,clinical trials,animal experiments,and the relationship between teachers and students.If medical graduate students are in the ethical dilemma in scientific research for a long time,their research activities will be greatly affected.By discussing the connotation,evaluation tools,current situation,influencing factors,and improvement measures of ethical dilemmas in scientific research,this paper proposed some suggestions,such as comprehensively investigating the influencing factors of ethical dilemmas in scientific research,and formulating targeted improvement measures,with a view to helping medical graduate students identify and get rid of ethical dilemmas in scientific research,and promote the stability of research activities.

Objective:To investigate the diagnostic value of different vaginal micro-environmental factors in low-grade cervical intraepithelial neoplasia (CIN Ⅰ) and determine the optimal model in high-risk human papillomavirus (HR-HPV) infection.Methods:A total of 926 women, including 623 with normal cervical (NC) condition and 303 CINⅠ patients, had undergone pathological examinations, and were enrolled in the study. All the women were from a community previously established cohort. Vaginal cleanliness, pH, H 2O 2, β-glucuronidase, coagulase, sialidase, and leukocyte esterase (LE) were detected by the combined detection method aerobic vaginitis/bacterial vaginosis in vaginal secretions. HPV genotyping was performed by using the flow-through hybridization technology. The data were analyzed by SAS 9.2 and SPSS 23.0. Results:The vaginal cleanliness, pH, sialidase, and LE were determined as the representative vaginal micro-environment factors by principal component analysis. Based on logistic regression theory to analyze the ROC curve, the results showed that the highest sensitivity was with pH value (76.2%), and the highest specificity was with sialidase (90.9%). The area under ROC curve were higher in combination detection modes of sialidase+LE (0.714), pH+sialidase+LE (0.719), vaginal cleanness+sialidase+LE (0.713) and pH+vaginal cleanness+sialidase+LE (0.709). According to HR-HPV infection status, the TOPSIS method was used to analyze the combined detection optimal model. Specifically, we found that the best diagnostic model was pH+sialidase +LE ( C i=0.585) in the HR-HPV positive group and vaginal cleanness+sialidase+LE ( C i=0.641) in the negative group. Conclusions:The combined detection of vaginal microenvironment factors could be used for auxiliary diagnosis for CINⅠ. It would be more effective when detecting pH, sialidase, and LE in HR-HPV positive women while vaginal cleanness, sialidase, and LE in HR-HPV negative women at the same time.

Objective:To investigate the effects of polycyclic aromatic hydrocarbons (PAHs) exposure on the prognosis of high risk human papillomavirus (HR-HPV) infection.Methods:In this prospective study, 564 patients with low-grade cervical intraepithelial neoplasia confirmed by pathology were selected from the natural cohort population established by our research group in Shanxi province in 2014. Based on the baseline data of demographic characteristics and factors related to HPV infection, the concentrations of 1-hydroxypyrene in urine samples of the patients were determined by high performance liquid chromatography to define the exposure level of PAHs. At baseline survey and follow-up after 24 months, flow-through hybridization was used to detect HPV infection types, and to evaluate the prognosis of HR-HPV (persistent infection, negative conversion, positive conversion and persistent negative status).Results:Of the 564 subjects, 483 completed the follow-up, with a follow-up rate of 85.6% (483/564). Among them, the persistent infection rate was 52.4% (75/143), the persistent homotype infection rate was 35.7% (51/143), the negative conversion rate was 47.6% (68/143), the positive conversion rate was 19.7% (67/340), and the persistent negative rate was 80.3% (273/340). The follow-up results showed that the persistent infection rate (a RR=3.22, 95% CI: 1.85-5.62) and positive conversion rate (a RR=2.84, 95% CI: 1.64-4.94) of HR-HPV in high PAHs exposure group were higher than those in low PAHs exposure group, while the persistent negative rate (a RR=0.55, 95% CI: 0.43-0.70) of HR-HPV in high PAHs exposure group were lower than those in low PAHs exposure group. Based on restrictive cubic spline analysis, the results showed that the effects of PAHs exposure on persistent HR-HPV infection and persistent homotype infection showed an ascending linear dose-response relationship, while on HR-HPV positive conversion and persistent negative status showed an ascending and declining nonlinear dose-response relationship respectively ( P<0.01). Conclusions:High PAHs exposure could promote persistent HR-HPV infection and persistent homotypic infection. Reducing PAHs exposure might conducive to HR-HPV continuous negative maintenance. Active prevention and control of PAHs exposure is of great significance to prevent HR-HPV infection and persistent infection.

Objective:To investigate the effect of red blood cell folate on the prognosis of high-risk human papillomavirus (HR-HPV) infection .Methods:A total of 564 participants with low-grade cervical intraepithelial neoplasias (CINⅠ) were selected from the community-based married women cohort established in 2014. The general baseline information and factors related to HPV infection were collected. Meanwhile, HPV genotyping and levels of folate were measured. The subjects were divided into different levels of exposure group according to the folate levels and followed up for 24 months to observe the changes of HR-HPV infection status. There were four changes, including persistent infection, infection turned negative, from negative to positive and constant negative by comparing HR-HPV infection status at baseline and follow-up to 24 months.Results:483 participators completed 24 months of follow-up observation, with a follow-up rate of 85.64% (483/564). The rates of persistent infection, infection turned negative, from negative to positive, and the constant negative were 52.45% (75/143), 47.55% (68/143), 19.71% (67/340), 80.29% (273/340), respectively. Our results demonstrated that the risk of persistent infection (a RR=2.50, 95% CI: 1.55-4.02) and from negative to positive (a RR=4.55, 95% CI: 2.52-8.23) in the low level of folate were significantly higher than that in the high level of folate, especially the risk of homotype persistent infection (a RR=2.72, 95% CI: 1.51-4.90). The risk of persistent infection (trend χ2=20.62, P<0.001), from negative to positive (trend χ2=31.76, P<0.001), persistent homotypic infection (trend χ2=20.09, P<0.001) increased with the decrease of red blood cell folate level. On the contrary, no similar results were found in persistent heterotypic infection. Conclusions:A low level of red blood cell folate could increase the risk of HR-HPV persistent infection and from negative to positive. In women with HR-HPV infection, the risk of persistent homotypic infection is higher.

Enzymes are widely used in chemical and pharmaceutical industries because of their advantages of high efficiency and specificity. However， the shortcomings of the free enzymes， such as poor stability and difficulty in recycling， limit their application. Therefore， the immobilization and application of enzymes have become one of the research hotspots. The selection of the immobilization carriers is a critical step in the process of enzyme immobilization. Metal-organic frameworks（MOFs）， a kind of porous materials， are formed by the coordination of metal ions or metal clusters with organic ligands. As an emerging immobilization carrier， its advantages such as high porosity， strong stability， and surface modifiability make it ideal for immobilized enzyme carriers. By immobilizing the free enzyme on MOFs， the above mentioned deficiencies of the free enzymes can be effectively solved， which greatly broaden the applicable condition. Ligand fishing is a method to find receptor-specific ligands from complex components， which has the advantages of high efficiency， simple sample pretreatment and high specificity. The MOF-enzyme complex formed by enzyme immobilization can act as a "fishing rod" for ligand fishing， which can screen out the targets from the complex system of components. The complex chemical composition and various active ingredients of traditional Chinese medicine（TCM） make the ligand fishing technology to play a big role in the screening of enzyme inhibitors from TCM. And the screened enzyme inhibitors are expected to be further developed into the lead compounds with good efficacy and low adverse effects， so the immobilized enzymes of MOFs have a wide application in the screening of active ingredients from TCM. Based on this， this paper summarized the methods of immobilized enzymes of MOFs in recent years， analyzed the characteristics， advantages and disadvantages of each method， and summarized the laws of preparation conditions and mechanisms. Meanwhile， the application and future development of immobilized enzymes of MOFs in the field of enzyme inhibitor screening from TCM were also summarized and prospected， with a view to providing a reference for the development of natural ingredients and the modernization of TCM.