Ultra-trace Ag doped carbon quantum dots with peroxidase-like activity for the colorimetric detection of glucose.

Carbon quantum dots (CQDs) have significant applications in nanozymes. However, previous studies have not elucidated the structure-activity relationship and enzyme mechanism. In this study, we employed a one-step microwave method to synthesize ultra-trace Ag-doped carbon quantum dots (Ag-CQDs). In the presence of hydrogen peroxide (H2O2), we used the oxidative coupling reaction of 3,3',5,5'-tetramethylbenzidine (TMB) to evaluate the intrinsic peroxidase-like activity, kinetics, and mechanism of Ag-CQDs. The trace amount of doped Ag (1.64 %) facilitated electron transfer from the CQDs interior to the surface. The electron transfer triggered the peroxide activity of CQDs, producing hydroxyl radical (·OH), which oxidized the colorless TMB to blue-colored TMB (oxTMB). By coupling with glucose oxidase (GOx), the Ag-CQDs/H2O2/TMB system has been used for colorimetric glucose determination. The system demonstrated a low detection limit (0.17 µM), wide linear range (0.5-5.5 µM), and satisfactory results when fruit juice was analyzed. This study reports a feasible method for the colorimetric detection of glucose by synthesizing ultra-trace Ag-doped carbon quantum dots with peroxidase-mimicking activity.

Association of sleep quality, depressive symptoms with non suicidal self injury among rural middle school students / 中国学校卫生

Objective@#To investigate the association of sleep quality, depressive symptoms and their interaction with non suicidal self injury (NSSI) among rural middle school students, so as to provide a reference for early prevention and control of NSSI among rural middle school students.@*Methods@#A multi stage cluster sampling method was used to randomly select four rural middle schools in Xuzhou, Jiangsu Province. A total of 1 723 middle school students were investigated according to the principle of grade stratification and class random selection. Paper questionnaires (including demographic factors, Non Suicidal Self Injury Short Scale, Pittsburgh Sleep Quality Index, Patient Health Questionnare-9) were used to conduct the questionnaire survey. Logistic regression model was used to analyze the association of sleep quality, depressive symptoms and their interaction with NSSI among rural middle school students.@*Results@#Totally 30.5% of middle school students had NSSI. Univariate results showed that girls (33.0%) had a higher incidence of NSSI than boys(27.3%), and those with sleep disorders and depressive symptoms had a higher incidence of NSSI, which was 46.8%, 43.6%. The results of multivariate Logistic regression showed that the risk of NSSI in students with sleep disorder was 1.80 times that in those without sleep disorder( OR 95%CI=1.42-2.28, P <0.01). The risk of NSSI in students with depressive symptoms was 3.32 times higher than that in those without depressive symptoms( OR 95%CI=2.60-4.24, P <0.01). The interaction results showed that there was additive interaction between sleep disturbance and depressive symptoms on the occurrence of NSSI behavior in rural middle school students, and the relative excess risk, attributable proportion and synergy index were 1.80, 0.30 and 1.57, respectively.@*Conclusion@#Sleep disorder and depressive symptoms are risk factors for NSSI among rural middle school students, and there is additive interaction between them.

Measurement of spino-pelvic anatomical parameters and finite element analysis of lower lumbar vertebra in lumbarization patients / 解剖学报

Objective To measure the sagittal anatomical parameters of the spine and pelvis based on EOS imaging system, and to evaluate the stress of the lower lumbar spine by finite element analysis (FEA). Methods A total of 44 subjects examined by EOS imaging system were included, including 11 sacral lumbar vertebra patients and 33 normal subjects. The sagittal plane parameters of lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS) were measured and compared in both groups. Pearson test was used to analyze the correlation between PI and LL in the two groups. At the same time, the finite element model of the lower lumbar vertebra was established. The stress condition of the lumbar spine model during forward bending, backward extension and left and right bending was evaluated by FEA method. Results The differences of PI, PT, SS and LL between the two groups were statistically significant (P<0.05). The correlation study found that there was a positive correlation between the two groups of subjects' PI and LL, including the lumbarization group (r = 0.69, P<0.05) and the normal group (r = 0.52, P<0.05). Under the conditions of forward bending, backward stretching, left bending and right bending, the bending moment of the model was 2 Nmm, and the stress concentration gradually decreased from bottom to top. The maximum stress concentration point was located at the lower articular process. Conclusion The physiological curvature and stress distribution of the lumbar spine in lumbarization population were different than normal, especially the stress concentration of the transitional intervertebral disc and articular process joint was obvious, and early degeneration of the spine was easy to occur.

Cardioprotective effects of limb ischemic postconditioning by different strength and time in rabbits / 中国应用生理学杂志

<p><b>OBJECTIVE</b>In this study, we try to find the better protocol of limb ischemia postconditioning by observing different protective effects of limb ischemic postconditioning (different strength and time windows in rabbits).</p><p><b>METHODS</b>42 healthy New Zealand rabbits were randomly divided into 7 groups (n = 6): Sham; Control (CON); Skeletal muscle postconditioning (SP); 6 min-delayed skeletal muscle postconditioning (6M-DSP); 1 min-delayed skeletal muscle postconditioning (1M-DSP); Strengthen skeletal muscle postconditioning (SSP); Weakened skeletal muscle postconditioning (WSP). Acute ischemia/reperfusion (I/R) model was induced by 45 minutes occlusion on left circumflex coronary artery (LCX) and 2 hours reperfusion in all anesthetized open-chest rabbits except the Sham. Limb ischemia was induced by external iliac arteries occlusion and reperfusion through artery clamps. The extent of myocardial infarction was assessed by triphenyltetrazolium (TTC) staining. Blood serum creatine kinase (CK) activity and lactate dehydrogenase (LDH) activity were measured at baseline,the end of ischemia, after 1 hour and 2 hours of reperfusion respectively.</p><p><b>RESULTS</b>Compared with the CON, the weight ratio and area ratio of myocardial infarction size were significantly decreased by 49.97% and 43.78% in SP, by 42.32% and 42.68% in 1M-DSP, by 48.36% and 48.86% in SSP (P < 0.05). But there was no significant difference between SP and 1M-DSP and SSP (P > 0.05). Otherwise, compared with the CON, myocardial infarct size was not significantly reduced in 6M-DSP or WSP (P > 0.05). The change of CK was similar to the trend of myocardial infarct size.</p><p><b>CONCLUSION</b>The limb ischemia strength of 5 mini/1 minR x 1 cycle could significantly reduce the myocardial ischemia/ reperfusion injury in rabbits, if it was achieved before myocardial reperfusion.</p>

Studies on cyclodextrin inclusion complexes of Dragon's blood and its tablets preparation / 中国中药杂志

<p><b>OBJECTIVE</b>To study the cyclodextrin inclusion complexes of Dragon's blood for improving the drug solubility and the preparation.</p><p><b>METHOD</b>The inclusion complexes were prepared with beta-cyclodextrin, HP-beta-cyclodextrin, SBE-beta-cyclodextrin and confirmed by DTA. The activity of the inclusion complex was tested by animal experiments. Inclusion complexes tablets were prepared and the dissolution test was performed.</p><p><b>RESULT</b>The solubility of inclusion complexes was increased to 13. 75-168. 39 times. The activity of the inclusion complex was markedly improved, and dissolution rate was 78.69%.</p><p><b>CONCLUSION</b>The cyclodextrin inclusion complexes of Dragon's blood have a good solubility, dissolution rate and pharmacological activity.</p>