The Systemic Immune Inflammatory Index Predicts No-Reflow Phenomenon after Primary Percutaneous Coronary Intervention in Older Patients with STEMI

Purpose:Coronary no-reflow phenomenon(NRP),a common adverse complication in patients with ST-segment eleva-tion myocardial infarction(STEMI)treated by percutaneous coronary intervention(PCI),is associated with poor patient prognosis.In this study,the correlation between the systemic immune-inflammation index(SII)and NRP in older patients with STEMI was studied,to provide a basis for early identification of high-risk patients and improve their prognosis.Materials and methods:Between January 2017 and June 2020,578 older patients with acute STEMI admitted to the Department of Cardiology of Hebei General Hospital for direct PCI treatment were selected for this retrospective study.Patients were divided into an NRP group and normal-flow group according to whether NRP occurred during the operation.Clinical data and the examination indexes of the two groups were collected.Logistic regression was used to analyze the independent predictors of NRP,and the receiver operating characteristic curve was used to further analyze the ability of SII to predict NRP in older patients with STEMI.Results:Multivariate logistic analysis indicated that hypertension(OR=2.048,95%CI:1.252–3.352,P=0.004),lymphocyte count(OR=0.571,95%CI:0.368–0.885,P=0.012),platelet count(OR=1.009,95%CI:1.005–1.013,P<0.001),hemoglobin(OR=1.015,95%CI:1.003–1.028,P=0.018),multivessel disease(OR=2.237,95%CI:1.407–3.558,P=0.001),and SII≥1814(OR=3.799,95%CI:2.190–6.593,P<0.001)were independent predictors of NRP after primary PCI in older patients with STEMI.Receiver operating characteristic curve analysis demonstrated that SII had a high predictive value for NRP(AUC=0.738;95%CI:0.686–0.790),with the best cut-off value of 1814,a sensitivity of 52.85%and a specificity of 85.71%.Conclusion:For older patients with STEMI undergoing primary PCI,SII is a valid predictor of NRP.

Effects of intracoronary arterial injection of tirofiban on no-reflow phenomenon in patients with acute ST-segment elevation myocardial infarction underwent primary percutaneous coronary intervention

Objective: To compare the effect of intracoronary arterial injection of tirofiban and sodium nitroprusside (SNP) on no-reflow phenomenon in patients with acute ST-segment elevation myocardial infarction (STEMI) underwent primary percutaneous coro-nary intervention (PCI). Methods: A total of 68 patients with acute STEMI who had no-reflow phenomenon during PCI were chosen and randomly divided into SNP group (n = 34) and tirofiban group (n = 34). Aiming at no-reflow phenomenon during PCI, with the use of microcatheters, intracoronary arterial injection of tirofiban was given in tirofiban group, while intracoronary bolus of SNP was given in SNP group. Coronary angiography was conducted to record TIMI flow grade of the infarct-related artery after 10 minutes. Plasma brain natriuretic peptide (BNP) was monitored before and after PCI (in 24 hours). With the help of ultrasound cardiogram, left ventricular ejection fraction (LVEF), left ventricular end-diastolic dimension (LVEDD) and left ventricular end-systolic dimension (LVESD) were recorded and compared in 30 days after PCI. Results: The ratio of TIMI grade 3 blood flow in tirofiban group was significantly higher than that in SNP group (76.5% (26/34) vs. 52.9% (18/34), p = .03)BNP levels in two groups had no statistical significance before PCI (p = .16), but in 24 h after PCI, BNP levels in tirofiban group were significantly lower than those in SNP group ((439.00 ± 4.90) μmol/L vs. (632.00 ± 3.63) μmol/L, p = .02)In 30 days after PCI, LVEF, LVEDD and LVESD in tirofiban group were all superior to those in SNP group (all p < .05). Conclusions: Intracoronary arterial injection of tirofiban was superior to SNP in improving no-reflow phenomenon in STEMI patients after PCI in the emergency treatment. Tirofiban therapy can increase coronary blood flow and myocardial perfusion after the occurrence of no-reflow phenomenon during PCI in STEMI patients, and improve long-term prognosis.

Convergence Phenomenon with Fourier Series of tg(x2)and Alike

The Fourier series of the 2π-periodic functions tg(x2)and 1sin(x)and some of their relatives (first of their integrals) are investigated and illustrated with respect to their convergence. These functions are Generalized functions and the convergence is weak convergence in the sense of the convergence of continuous linear functionals defining them. The figures show that the approximations of the Fourier series possess oscillations around the function which they represent in a broad band embedding them. This is some analogue to the Gibbs phenomenon. A modification of Fourier series by expansion in powers cosn(x)for the symmetric part of functions and sin(x)cosn−1(x)for the antisymmetric part (analogous to Taylor series) is discussed and illustrated by examples. The Fourier series and their convergence behavior are illustrated also for some 2π-periodic delta-function-like sequences connected with the Poisson theorem showing non-vanishing oscillations around the singularities similar to the Gibbs phenomenon in the neighborhood of discontinuities of functions. .

Intracoronary nitroprusside in the prevention of the no-reflow phenomenon in acute myocardial infarction

Background No-reflow phenomenon during percutaneous coronary intervention （PCI） for acute myocardial infarction （AMI） is a predictive factor of continuous myocardial ischemia, ventricular remodeling and cardiac dysfunction, which is closely associated with a worse prognosis. This study aimed to evaluate intracoronary nitroprusside in the prevention of the no-reflow phenomenon in AMI.Methods Ninety-two consecutive patients with AMI, who underwent primary PCI within 12 hours of onset, were randomly assigned to 2 groups： intracoronary administration of nitroprusside （group A, n=46）, intracoronary administration of nitroglycerin （group B, n=46）. The angJographic results were observed. The real-time myocardial contrast echocardiography （RT-MCE）, including contrast score index （CSI）, wall motion score index （WMSI）, transmural contrast defect length （CDL） and serious WM abnormal length （WML） were recorded at 24 hours and 1 week post-PCI. High sensitivity C-reactive protein （Hs-CRP） was examined by immune rate nephelometry. N-terminal prohormone brain natriuretic peptide （NT-proBNP） was tested with enzyme-linked immunosorbent assay. Patients were followed up for six months. Major adverse cardiac events （MACE） were recorded. Results The incidence of final TIMI-3 flow in group A was much higher than that in Group B （P 〈0.05）, final corrected TIMI frame count （cTFC） in group A decreased significantly than that in group B （P 〈0.01）. The CSI, CDL/LV length, WMSI and WL/LV length in group A were significantly lower than that in group B （P 〈0.01）. Levels of Hs-CRP and NT-proBNP at 1 week post-PCI decreased significantly in group A than that in group B （P 〈0.01）. Patients were followed up for 6 months and the incidence of MACE in group A was significantly lower than that in group B （P〈0.05）.Conclusion Intracoronary nitroprusside can improve myocardial microcirculation, leading to the decrease of the incidence of no-reflow phenomenon and better prognosis.

Clinical significance of intra-aortic balloon pumping on no-reflow phenomenon of primary percutaneous coronary intervention for acute myocardial infarction

Background Percutaneous coronary intervention （PCI） is used as a treatment for acute myocardial infarction （AMI）, and one of its major complications is the angiographic no-reflow phenomenon （NR）. Although intra-aortic balloon pumping （IABP） is sometimes used in such patients to increase the diastolic coronary blood flow, there is little available information regarding the effects of IABP on the angiographic no-reflow phenomenon. Method Twenty-two AMI patient with NR were performed primary PCI between January 2006 and December 2009, of which 12 patients were selected for IABP therapy and the left 10 were selected as the control group by group procedure of odd and even days; We observed the vasoactive substance in both groups on the days of 1, 2, 3, 5, 7, 10 after the different interventions, which include plasma renin activity （PRA）, angiotensin Ⅱ （ANG Ⅱ）, aldosterone （ALD）, adrenaline （E）, and noradrenalin （NE）; In addition, cardiac structure and cardiac ventricle systolic function including left atrium medial diameter （LAMD）, left ventricular medial diameter （LVMD） Finally, left ventricular ejection fraction （LVEF） were evaluated after 10 days, 3 months and 6 months; statistics was taken to analysis. Results According to the time concentration curve, vasoactive substance of the IABP group decreased faster than that of the control group, and this difference had statistical significance （P 〈 0.01 ） ; In terms of LAMD, LVMD, and LVEF, echocardiography difference of the IABP and the control group in 10 days, 3 months, and 6 months also showed statistical significance （P 〈 0.05）. Conclusions IABP can significantly reduce the release of vasoactive substances of NR in patients of primary PCI for AMI; LAMD, LVMD and LVEF in 10 days, 3 months, and 6 months can be improved using this method, which is conducive to recovery of heart function.

Application of intra-aortic balloon pumping on no-reflow phenomenon in primary PCI for STEMI

Background To investigate the effect of intra-aortic balloon pumping （IABP） on no-reflow phenomenon primary percutaneous coronary intervention （PCI） for ST-Elevation Myocardial Infarction （STEMI）. Methods Clinical data of 22 acute myocardial infarction patients after PCI with angiographic no-reflow phenomenon were retrospectively analyzed between January 2006 and December 2009.12 patients underwent IABP, other 10 patients as control group. We observed difference of cardiac structure, brain natriuretic peptide （BNP） and ventricular systolic function between two group, as well as cardiac injury markers （MYO,CK-MB, cTnI） in both groups on the days of 1, 2, 3, 5, 7, 10 after the different interventions. In addition, cardiac structure and ventricular systolic function including left atrium medial diameter （LAMD）, left ventricular medial diameter （LVMD）, left ventricular ejection fraction （LVEF） was evaluated after 10 days, 3 months,6 months Finally, statistics was used to analysis the data. Results The several vasoactive substances as well as cardiac injury markers and LAMD, LVMD, LVEF of 10 days, 3 months, 6 months of IABP group were significant difference with control group significant difference （P 〉 0.0 PCI with angiographic no-reflo （P 〈 0.05）. 5）. Conclusions w phenomenon, BNP targets of IABP group compared with the control group no IABP has effects on prognosis in STEMI patients who performed which is conducive to recovery of heart function.

Feasibility of lymphocyte-to-monocyte ratio in predicting no-reflow phenomenon in ST-elevation myocardial infarction patients undergoing primary percutaneous coronary intervention

Background The no-reflow phenomenon is correlated with adverse effects on short-term and long-term outcomes of ST-elevation myocardial infarction(STEMI) in patients undergoing primary percutaneous coronary intervention(PCI). The lymphocyte-to-monocyte ratio(LMR) is a novel inflammatory marker which is associated with slow coronary flow. We aimed to investigate the predictive value of LMR for no-reflow phenomenon in patients with STEMI undergoing primary PCI. Methods A total of 1350 STEMI patients were enrolled in this study from January 2014 to January 2018. Blood samples were obtained at initial admission for analysis of LMR.The univariate and multivariate logistic regression analysis was performed to study the relationship between LMR and no-reflow phenomenon. Results All the 156 patients among the study population suffered from no-reflow phenomenon during the procedure. The LMR level was significantly lower in patients with no-reflow(1.6 ±1.0 vs. 3.25 ± 1.8, P<0.001). Multivariate logistic regression analysis showed that LMR was independently associated with no-reflow post primary PCI in STEMI patients.(OR 2.356, 95% CI 1.201-5.945;P=0.030). The area under the ROC curve for the LMR was 0.757 [95% confidence interval(CI) 0.686-0.828, P<0.001]. Conclusions LMR at admission could serve as a biomarker for no-reflow phenomenon in patients undertaken primary PCI for STEMI.[S Chin J Cardiol 2019;20(4):228-235]

Intracoronary pressure gradient measurement in acute myocardial infarction patients with the no-reflow phenomenon during primary percutaneous coronary intervention

Background:Various experimental and clinical studies have reported on coronary microcirculatory dysfunction("no-reflow"phenomenon).Nevertheless,pathogenesis and effective treatment are yet to be fully elucidated.This study aimed to measure the intracoronary pressure gradient in the no-reflow artery during emergent percutaneous coronary intervention and explore the potential mechanism of no-reflow.Methods:From September 1st,2018 to June 30th,2019,intracoronary pressure in acute myocardial infarction patient was continuously measured by aspiration catheter from distal to proximal segment in the Department of Coronary Care Unit,Tianjin Chest Hospital,respectively in no-reflow arteries(no-reflow group)and arteries with thrombolysis in myocardial infarction-3 flow(control group).At least 12 cardiac cycles were consecutively recorded when the catheter was pulled back.The forward systolic pressure gradient was calculated as proximal systolic pressure minus distal systolic pressure.Comparison between groups was made using the Student t test,Mann-Whitney U-test or Chi-square test,as appropriate.Results:Intracoronary pressure in 33 no-reflow group and 26 in control group were measured.The intracoronary forward systolic pressure gradient was-1.3(-4.8,0.7)and 3.8(0.8,8.8)mmHg in no-reflow group and control group(Z=-3.989,P<0.001),respectively,while the forward diastolic pressure gradient was-1.0(-3.2,0)and 4.6(0,16.5)mmHg in respective groups(Z=-3.851,P<0.001).Moreover,the intracoronary forward pressure gradient showed significant difference between that before and after nicorandil medication(Z=-3.668,P<0.001 in systolic pressure gradient and Z=-3.530,P<0.001 in diastolic pressure gradient).Conclusions:No reflow during emergent coronary revascularization is significantly associated with local hemodynamic abnormalities in the coronary arteries.Intracoronary nicorandil administration at the distal segment of a coronary artery with an aspiration catheter could improve the microcirculatory dysfunction and resume normal coronary pressure gradient.Clinical trial registration:www.ClinicalTrials.gov(No.NCT 03600259).

Asymmetric Environmental Regulation:Mechanism and a Yardstick Phenomenon

In discussing the policy effects of environmental regulation,we should focus not only on whether environmental regulation helps improve the environmental and economic performance of firms,but also on how such improvement is materialized,i.e.whether the obsolete mode of production is reversed.After matching the database of China’s industrial enterprises with that of pollution emissions from these industrial enterprises,this paper identifies the asymmetric scope of clean production standards to test the effect of environmental regulation on the total factor productivity(TFP)of the industrial enterprises.Our empirical research finds that the implementation of clean production standards may induce TFP improvement.However,such improvement only occurs for polluters who cannot or who barely meet clean production standards and does little to improve the production standards of polluters with low pollution emission,reflecting the yardstick phenomenon of the asymmetric environmental regulation policy effect:While polluters are forced to improve,clean enterprises that pollute less are more likely to take no action.Further research finds that such TFP improvement is materialized primarily by means of overall firm optimization;the compensation effect is insignificant and does not reverse the backward mode of production.Polluters cope with the implementation of clean production standards by purchasing more equipment and expanding capacity,which adds to the tension between the expansion of capacity and the abatement of pollution emission.

Correction of dynamic Brazilian disc tensile strength of rocks under preloading conditions considering the overload phenomenon and invoking the Griffith criterion

Dynamic tensile failure is a common phenomenon in deep rock practices,and thus accurately evaluating the dynamic tensile responses of rocks under triaxial pressures is of great significance.The Brazilian disc(BD)test is the suggested method by the International Society for Rock Mechanics and Rock Engineering(ISRM)for measuring both the static and dynamic tensile strengths of rock-like materials.However,due to the overload phenomenon and the complex preloading conditions,the dynamic tensile strengths of rocks measured by the BD tests tend to be overestimated.To address this issue,the dynamic BD tensile strength(BTS)of Fangshan marble(FM)under different preloading conditions were measured through a triaxial split Hopkinson pressure bar(SHPB).The fracture onset in BD specimen was captured through a strain gage around the disc center.The discrepancy between the traditional tensile strength(TTS,determined by the peak load P_(f) of the BD specimen)and the nominal tensile strength(NTS,obtained from the load P_(i) when the diametral fracture commences in the tested BD specimen)was applied to quantitatively evaluating the overload phenomenon.The Griffith criterion was used to rectify the calculation of the tensile stress at the disc center under triaxial stress states.The results demonstrate that the overload ratio(s)increases with the loading rate(σ)and decreases with the hydrostatic pressure(σ_(s)).The TTS corrected by the Griffith criterion is independent of theσ_(s)due to the overload phenomenon,while the NTS corrected by the Griffith criterion is sensitive to both the andσ.Therefore,it is essential to modify the tensile stress in dynamic confined BD tests using both the overload correction and the Griffith criterion rectification to obtain the accurate dynamic BTS of rocks.

Medical and interventional therapy of Kasabach-Merritt phenomenon associated with Kaposiform hemangioendothelioma:A case report

An infant with Kasabach-Merritt Phenomenon(KMP)presented with a giant subcutaneous mass in the right lower limb,severe hypofibrinogenemia,and thrombocytopenia.Glucocorticoids,along with supportive treatments including transfusion of blood products and clotting factors,were administered to reverse fatal disseminated intravascular coagulation and acute hemolysis.The glucocorticoid dose was tapered slowly,and sirolimus was added to treat the hemangiomas.The patient subsequently underwent interventional therapy.After 6 months of medical and interventional therapy,the patient was doing well with a normal platelet count,the tumor volume was markedly reduced,and the primary cutaneous lesion became pale pink.Currently,the patient remains on sirolimus,and no recurrence of thrombocytopenia or further growth of the mass was observed after six months of follow-up.

Anesthetic management of a patient with preoperative R-on-T phenomenon undergoing laparoscopic-assisted sigmoid colon resection:A case report

BACKGROUND The R-on-T phenomenon is a malignant arrhythmia associated with potentially catastrophic consequences.It may initiate ventricular tachycardia or ventricular fibrillation,which can result in syncope or sudden cardiac death.This manifestation poses a great challenge for anesthesiologists.However,it is rarely encountered in the perioperative setting.CASE SUMMARY We herein present a case in which the R-on-T phenomenon was incidentally revealed by 24-h Holter monitoring in a patient diagnosed with sigmoid colon cancer.Careful evaluation and treatment with mexiletine were carried out preoperatively under consultation with a cardiovascular specialist,and surgery was uneventfully performed under general anesthesia after thorough preparation.CONCLUSION Physicians should be vigilant about this infrequent but potentially fatal arrhythmia.Our experience suggests that the anesthetic process can be greatly optimized with careful preparation.

circRNA CCND1对人肝癌HepG2细胞增殖、凋亡、侵袭和迁移的影响

目的 探讨circRNA CCND1对人肝癌HepG2细胞增殖、凋亡、侵袭和迁移的影响。方法 采用荧光原位杂交(FISH)实验及实时荧光定量聚合酶链反应(qRT-PCR)检测circRNA CCND1在HepG2细胞及L02细胞中的表达情况;进一步干扰及过表达circRNA CCND1后,通过qRT-PCR检测circRNA CCND1在HepG2细胞中的表达情况,CCK-8法和EDU法检测HepG2细胞增殖情况,流式细胞术检测细胞凋亡、细胞周期,Transwell实验检测细胞侵袭情况,划痕实验检测细胞迁移情况。结果 HepG2细胞circRNA CCND1相对表达量较LO2细胞高(P <0.05)。Si-circRNA CCND1组circRNA CCND1相对表达量较Control组和Si-NC组下降(P <0.05),Oe-circRNA CCND1组较Control组和Oe-NC组升高(P <0.05)。各组细胞培养0、24、48、72和96 h后细胞增殖活性比较,经重复测量设计的方差分析,结果:(1)不同时间点细胞增殖活性比较,差异有统计学意义(P <0.05);(2)各组细胞增殖活性比较,差异有统计学意义(P <0.05);(3)各组细胞增殖活性变化趋势比较,差异有统计学意义(P <0.05)。与Control组及Si-NC组比较,Si-circRNA CCND1组细胞凋亡率升高(P <0.05),G_(0)/G_(1)期比值升高(P <0.05),S及G_(2)/M期比值下降(P <0.05);与Control组及Oe-NC组比较,OecircRNA CCND1组细胞凋亡率下降(P <0.05),G_(0)/G_(1)期比值下降(P <0.05),S及G_(2)/M期比值升高(P <0.05)。Si-circRNA CCND1组细胞侵袭数、细胞迁移数较Control组、Si-NC组少(P <0.05),Oe-circRNA CCND1组较Control组及Oe-NC组多(P <0.05)。结论 circRNA CCND1能够促进人肝癌细胞HepG2细胞增殖、侵袭和迁移,抑制细胞凋亡。

苦黄注射液预防抗结核药物导致的药物性肝损伤患者疗效研究

目的本研究观察了应用苦黄注射液预防抗结核药物诱发药物性肝损伤(DILI)的作用,以避免不合理的抗痨中断治疗。方法2022年3月~2022年11月我院收治的97例肺结核患者,被随机分为试验组50例和对照组47例。所有患者均接受标准的2HREZ/4HR抗结核治疗,试验组在此治疗的基础上加用苦黄注射液治疗8周。采用ELISA法检测血清白介素6(IL-6)和肿瘤坏死因子-α(TNF-α),采用放射免疫法检测血清血红素加氧酶(HO-1)和超氧化物歧化酶(SOD)水平。结果在治疗4周末,试验适应性肝损伤和DILI发生率分别为6.0%和2.0%,显著低于对照组的17.0%和8.5%(P<0.05),在治疗8周末,试验组适应性肝损伤和DILI发生率分别为6.0%和4.0%,显著低于对照组的21.3%和17.0%(P<0.05);在治疗8周末,试验组血清ALT、AST和TBIL水平分别为(28.4±23.4)U/L、(30.8±18.7)U/L和(12.9±7.3)μmol/L,显著低于对照组【分别为(53.1±33.1)U/L、(52.5±37.7)U/L和(20.1±10.9)μmol/L,P<0.05】;试验组血清HO-1和SOD水平分别为(200.3±14.0)U/L和(418.0±18.7)U/L,显著高于对照组【分别为(128.8±21.4)U/L和(318.0±15.1)U/L,P<0.05】,而血清IL-6和TNF-α水平分别为(11.4±1.9)ng/L和(9.3±1.8)ng/L,显著低于对照组【分别为(17.5±4.0)ng/L和(14.5±3.0)ng/L,P<0.05】。结论在抗痨开始时应用苦黄能够显著降低DILI的发生,尽可能地维持标准化抗结核治疗,且安全性良好。

预电离间隙击穿特性及其对中储开关击穿稳定性的影响

紫外预电离中储开关是大型强电磁脉冲模拟装置的关键器件,中储开关预电离间隙击穿特性是影响开关性能的一个重要因素。在N_(2)气压为0.1~0.7 MPa的工作环境中,开展了预电离间隙的击穿特性及其对中储开关击穿稳定性影响的实验研究。预电离间隙的击穿特性实验结果表明,随着气压的增加,预电离间隙击穿电压呈现出不同的变化趋势:间隙距离较短时,击穿发生在预电离间隙钨针和铜电极之间的气体介质中,击穿电压呈现出渐进饱和的趋势;间隙距离较长时,低气压下的击穿发生在预电离间隙中,高气压条件下击穿发生在预电离电极的陶瓷套管表面气体介质中,此时击穿电压几乎不随气压发生变化。在电磁脉冲模拟装置中开展了预电离间隙击穿特性对紫外预电离中储开关击穿特性影响的实验,结果表明,当中储开关内部气压很高时,开关击穿分散性大于低气压区域。该结果可能与预电离间隙在高气压区域时击穿发生在陶瓷套管上有关,该现象导致预电离间隙击穿过早,使得预电离间隙击穿时刻与主间隙波形波峰时刻之间的时间差大于主间隙击穿的形成时延,从而增大了主间隙击穿电压的分散性。

身份置换下的多元书写——论明代散曲中的代笔现象

在明代,代笔散曲的题材范围较为宽泛,其中代人赠妓或代妓赠人类曲作最多,此外还有代人抒怀、悼内、劝诫、恭贺、饯行、邀柬、嘲谑等曲作。明代散曲代笔现象的产生和多元发展,究其原因,主要有以下几个方面:一是明代文士对代笔传统的承继;二是作者的个人兴趣,以及代笔的获利、抒情、交际、娱乐等功用;三是明代重情纵欲思潮影响下的士风;四是散曲较少受到名教渗透的文体特点。这一现象具有其不可忽视的文化价值与意义。

论小学教师的性别素养——基于小学教育中性别现象的思考

我国小学教育中广泛存在着两种性别现象,一种是反映在教育教学中的性别差异现象,一种是小学女教师偏多的性别失衡现象。本研究通过揭示小学教育中客观存在的性别现象,超越生物本质视角与社会建构视角,回到教育自身来认识小学教育中的性别问题。基于此,本研究在小学教师专业伦理视域下提出小学教师应具备一定的性别素养,立足小学生的“向善性”、小学教师的“示范性”、小学教育的“发展性”,小学教师在教书育人的过程中应遵从性别敏感、性别公正、性别友好三项伦理原则。小学教师性别素养的伦理原则及教育价值可以帮助师生基于性别存在又超越性别存在,不断趋向教育之终极善,即“培养完整的人”这一育人目标。

空化现象对水导激光微水束稳定性的影响研究

为了探寻空化现象对水导激光微水束稳定性影响,利用计算流体动力学的方法,分别在不考虑空化和考虑空化的情况下,对从典型喷嘴出射的水射流进行了数值模拟分析,研究了空化现象的产生机理及对微水束稳定性的影响。结果表明,在入口直径为0.1 mm、圆柱段长径比为1、上边缘锐利的喷嘴结构下,随着入口压力从0.2 MPa增大到16 MPa,水射流与喷嘴壁面分离后再次附着的长度逐渐增大,并且空化会导致该长度延长;在入口压力小于6 MPa的情况下,不考虑空化的水射流在稳定后会贴着喷嘴壁面流下,而添加空化模型使得水束形成翻转流。该研究对设计满足水导激光工艺的喷嘴结构有着重要的参考价值。

美国大学生运动员奥运夺冠现象的多维审视与思考

奥运冠军是彰显竞技体育人才培养质量的显著标志,审视美国大学生运动员奥运夺冠的独特现象,对我国大学竞技体育高质量发展具有一定启示。运用文献研究法和对比分析法对美国大学生运动员奥运夺冠现象进行多维分析。研究认为:美国凭借大学生运动员征战奥运的悠久历史经验、庞大的奥运参赛规模、均衡的奥运项目布局、强劲的竞技体育实力,助力美国奥运代表团位居奥运会金(奖)牌榜前列;通过多元协同的管理机制、深入推进的法治建设、健全完善的人才选拔机制、科技赋能的备战举措、结构均衡的赛事系统、支撑有力的服务保障,实现了美国以大学生运动员为主体的奥运夺冠路径。建议:在新发展阶段,我国应进一步深化大学竞技体育体制改革,加快大学竞技体育法治建设步伐,创新大学竞技体育人才选拔模式,转变大学生运动员训练备战方式,完善大学竞技体育竞赛结构体系,强化大学竞技体育服务保障。

颞叶癫痫患者术后EEG尖慢波表现类似ECG“R-on-T”现象的1例报告

“R-on-T”现象为心电图的一种表型,被认为是下一个心室收缩提前落在上一周期心室易损期内,通常会引起恶性心律失常。本文介绍1例癫痫患者行右颞病灶切除术及选择性海马杏仁核切除术后,在过度换气诱发试验中脑电图尖慢波表现为类似“R-on-T”同源机理现象的病例,并对该现象产生的可能机制进行讨论,旨在提示神经电生理与心脏电生理具有同源性,进一步拓宽电生理理论学习、延伸电生理诊断思维。