In this study, we applied generalized autoregressive conditional heteroskedasticity (GARCH) model to conditional fluctuation characteristics of heart rate variation (HRV) series (congestive heart failure, Normal), with all the data from PhysioNet ECG database. Research results proved the existence of condition fluctuation characteristic in the series of changing rate of HRV. In the GARCH model family, threshold GARCH (1,1)(TGARCH (1,1)) model performs best in fitting changing rate of HRV. Although the structure of ARCH (1) model is simple, its error is the closest to that of TGARCH (1, 1) model. The results also showed that the difference was obvious between disease group and normal group. All these results provide a new method to the research and clinical application of HRV.
Cardiology ; trends ; Heart Failure ; physiopathology ; Heart Rate ; Humans ; Models, Cardiovascular

Objective To establish a sensitive and specific liquid chromatography method for the determination of loganin and morroniside in rat serum containing Liuwei Dihuang Formula(LDF).Methods Loganin and morroniside were extracted from the rat serum using SPE column,then separated on a C_(18)column.A HPLC method for determining serum concentration of mor- roniside and loganin in rats before and after administration LDF was established.Results A good linear calibration curve of lo- ganin and morroniside was obtained.The recovery of the method was in the range of 95 %～105 %.The extracted recovery was more than 75 % ,and within-day and intra-day precisions were less than 12 %.Conclusion This method is sensitive, simple and rapid for monitoring of drug level in the study on pharmacokinetics and different combination of LDF.

Background Recent researches show that oxidative stress is involved in the progress of keratoconus.Nuclear factor-E2-related factor 2-antioxidant response element (Nrf2-ARE) pathway plays a critical role in the defense against oxidative stress,but its function in keratoconus is unclear.Objective To investigate the differences of Nrf2-ARE signaling activation and matrix degenerating enzymes between keratoconus and normal corneal stromal cells.Methods Corneal stromal cells were isolated from keratoconus and normal cornea by using dispase and collagenase digestion.The cells were treated with hydrogen peroxide (H2O2) to mimic in vivo oxidative stress condition.Reactive oxygen species (ROS) production was measured by fluorescence substrate DCHF-DA incubation.Nrf2 level and the expression of Nrf2-ARE downstream antioxidant genes were analyzed by Western blot and real-time quantitative-PCR(RT-qPCR).The activity of matrix degenerating enzymes,including urokinase-type plasminogen activator (uPA)-uPA receptor (uPAR) system and matrix metalloproteinase-2 (MMP-2) were assessed by Western blot and gelatin zymography respectively.Results In normal culture,keratoconus corneal stromal cells assumed increased basal ROS and Nrf2 level when compared with normal cells(t =18.155,P＜0.01).However,after H2O2 treatment,the keratoconus corneal stromal cells showed increased ROS production,while decreased Nrf2 translocation and no significant difference in expression levels of Nrf2-ARE downstream antioxidant genes (Nrf2:t =62.123,P＜ 0.01 ; (nicotinamide adenine dinucleotide phosphate quinine oxidoreductase-1 [NQO-1]:t =2.209,P =0.092 ; hemo oxygenase-1 [HO-1]:t =0.293,P =0.784 ; superoxide dismutase [SOD2]:t =0.749,P =0.495).The contents of uPA-uPAR and the activity of MMP-2 also showed a higher level in keratoconus corneal stromal cells than normal cells,with significant differences between them (t =19.164,15.458,4.818,all at P＜0.01).Conclusions The defect of Nrf2-ARE signaling activation exists in the keratoconus corneal stromal cells,and correlats with the abnormal expression level of stromal degeneration enzymes,which suggests that the defect of Nrf2-ARE signaling activation may be involved in the progression of keratoconus.

Low carbohydrate diet (LCD), as an adjunctive therapy of type 1 diabetes (T1DM), has attracted much attention in recent years, but its exact efficacy and safety have not yet been determined. Limited literature has reported that LCD plays an important role in controlling blood sugar and its complications in T1DM patients, regulating intestinal microbiota, and autoimmunity. This article elaborates on the research progress of T1DM medical nutritional therapy related to LCD mode in recent years, including its control of blood sugar, adverse reactions, and regulation of intestinal microbiota.

Objective:To explore the effects of competency-based diversified training on the bedside nursing comprehensive ability aand transition shock of newly recruited nurses.Methods:A total of 62 newly recruited nurses from the Second Affiliated Hospital of Zhengzhou University in June 2018 were selected as the control group, and 70 newly recruited nurses from June 2019 were selected as the experimental group by cluster sampling. The control group received routine pre-job training, and the experimental group received diversified training based on the control group. After one year of training, the differences in the scores of bedside nursing comprehensive ability, post competency and transition shock between the two groups of nurses were analyzed.Results:After 1 year of training, the total scores and the scores of nursing problems, nursing evaluation, nursing plan, nursing theory, nursing operation and bedside nursing comprehensive ability in the experimental group were 12.20±1.76, 24.29±2.38, 13.54±1.88, 9.77±1.35, 15.14±2.30 and 79.24±6.59, which were all higher than those of the control group (10.26±1.55,22.31±1.84,10.45±1.58, 8.56±1.80, 13.27±2.38 and 69.82±4.09), the differences were statistically significant ( t value was 4.582-13.679, P<0.05). The total scores and the scores of each dimension of the Post-competency the experimental group were 31.46 ±4.32, 51.03± 4.64, 20.27± 3.78, 17.86±3.99, 58.43± 4.44, 179.37±9.97, which were all higher than those of the control group 24.76±4.12, 40.56±5.55, 16.61±2.88, 15.15± 2.96, 49.74±3.07, 146.66±17.98, the differences were statistically significant ( t value was 4.466-13.197, P<0.05). The scores of psychological knowledge, skills, social culture and development and the total scores of Transition shock in the experimental group were 30.90±3.15, 19.69±2.74, 32.17±3.06, 103.81±12.24, which were all higher than those in the control group (25.69±2.76, 15.92±3.24, 27.50±4.15, 88.32±11.54), the differences were statistically significant ( t value was 7.237-10.040, P<0.05). Conclusions:competency-based diversified training can effectively improve the bedside nursing comprehensive ability and post competency, reduce their transition shock, and has strong clinical reference significance.