“师法”向“门阀”的演进——“偃武修文”与东汉文人的士族化

东汉初年,政府推行"偃武修文"的国策,私学蓬勃发展。拥有众多弟子的经师们不仅声名远播,而且具备举荐人才、推荐弟子入仕为官的权力。经师及其推荐入仕的弟子们,父子相传,师徒相依,代代为官,逐渐拥有了雄厚的物质基础和丰富的人脉,于是"士族化"进程迅速开启,形成了一种具有"开放性"的"门阀制度"的雏形。在这一进程中,西汉以来的"师法"体制走向没落而"门阀"制度最终得以形成。

东晋“门阀政治”说献疑

已故著名史学家田余庆先生《东晋门阀政治》(以下简称“田著”)以提出东晋为“门阀政治”时代而著称。然田著在理论阐释和史实分析两个方面都有值得商榷之处。田著对“门阀政治”这一核心概念的定义含混而模糊,在其多种说法中尤强调两个特征:一是士族与皇权的“共治”,二是门阀士族势力“平行于皇权或超越于皇权”。但这两点并不能证明东晋为“门阀政治”时代。君臣“共治”乃中国古代政治的常态而非“变态”,东晋百年亦然,士族与皇权“共治”并未改变东晋皇权政治的基本性质。田著强调东晋“权力结构”发生了变化,也与史实不符,东晋以皇帝专权为核心、执行皇权政治的官僚体制为基础的皇权政治“权力结构”并未发生根本性变化。秦至清两千多年间,官僚或其它势力集团的权力“平行于皇权或超越于皇权”为皇权政治波浪起伏运行中的常态,东晋及其之前、之后皆然,以此作为东晋“门阀政治”的理据并不能成立。田著将次等士族与门阀士族的矛盾视为东晋末年的社会主要矛盾,并在此根本性错误前提下分析东晋末年的其他各种矛盾关系,从而得出东晋“门阀政治”的错误结论。实际上,东晋社会的主要矛盾仍然是“皇权与吏民”的矛盾,故东晋仍是皇权政治时代,而非所谓“门阀政治”时代。

Transcatheter aortic valve replacement and stroke： a comprehensive review

Transcatheter aortic valve implantation （TAVR） has emerged as an alternative, rapidly evolving treatment option for patients with se- vere aortic stenosis and high surgical risk. Stroke is a devastating complication being confined mainly in the periprocedural and 30-day pe- riod following TAVR, with a lower and relatively constant frequency thereafter. Early stroke is mainly due to debris embolization during the procedure, whereas later events are associated with patient specific factors. Despite the fact that the rate of clinical stroke has been constantly decreasing compared to initial TAVR experience, modern neuro-imaging with MRI suggests that new ischemic lesions post-TAVR are almost universal. The impact of the latter is largely unknown. However, they seem to correlate with a reduction in neurocognitive function. Because TAVR is set to expand its indication to lower surgical-risk patients, stroke prophylaxis during and after TAVR becomes of paramount importance. Based on clinical and pathophysiological evidence, three lines of research are actively employed towards this direction： improvement in valve and delivery system technology with an aim to reduce manipulations and contact with the calcified aortic arch and native valve, antithrombotic therapy, and embolic protection devices. Careful patient selection, design of the procedure, and tailored antithrombotic strategies respecting the bleeding risks of this fragile population constitute the main defense against stroke following TAVR.

Mixed refrigerant composition shift due to throttle valves opening in auto cascade refrigeration system

Auto cascade refrigeration(ACR) cycle with phase separators is widely used in the cryogenic system. The composition of mixed refrigerant has a great effect on the performance of the system. Based on the assumption of infinite volume of phase separator, ACR system with one phase separator is simulated in this paper. The variation of refrigerant composition under different valves opening is obtained. A related experimental system is set up to verify the variation. The result shows that when the valve opening connected to the evaporator increases or the valve opening under the phase separator decreases, the low-boiling component concentration of the working mixture passing through the compressor and condenser increases, while the high-boiling component concentration decreases. Furthermore, the variations of condensation pressure and evaporation pressure under different valves opening are also observed. This paper is helpful to deepen the understanding of ACR system.

Transcatheter versus surgical aortic valve replacement in severe, symptomatic aortic stenosis

Aortic stenosis （AS） is the most common type of valvular heart disease in the elderly. Surgical aortic valve replacement （SAVR） has been the standard practice for treating severe, symptomatic AS, but recently new treatment options have emerged, Transcatheter aortic valve replacement （TAVR） is now an established treatment option in patients at high surgical risk. In this review, we focus on recent developments and compare the two treatment methods in specific populations in terms of efficacy and safety （e.g., in patients with history of prior thoracic surgery, type of anesthesia employed, access site used or need for permanent pacing）. The impact of comorbidities （pulmonary hypertension, arterial hypertension and obesity paradox）, the cost-effectiveness of TAVR vs. SAVR and advances in transcatheter valve technology as well as issues that merit further investigation are further discussed. Moreover, outcomes and complications of TAVR in patients of different risk category （extremely high, high, intermediate and low risk） are analyzed. We strongly believe that during the following years, TAVR may evolve as the treatment of choice in a broader group of patients with symptomatic AS and beyond those with intermediate and high-risk features.

Long-term follow-up of quality of life in high-risk patients undergoing transcatheter aortic valve implantation for symptomatic aortic valve stenosis

Background Transcatheter aortic valve implantation （TAVI） has become the standard treatment for patients with severe symptomatic aortic stenosis （AS） considered at very high risk for surgical aortic valve replacement. The purpose of this sub-study was to evaluate long-term （〉 4 years） health-related quality of life （QoL） in octogenarians who underwent TAVI. Methods A single center observational registry in twenty patients who underwent frame analysis assessment ≥ 4 years after TAVI. Health-related QoL was evaluated, using the Short Form-36 （SF-36）, the EuroQoL-5D （EQ-5D） and the visual analogue score （EQ-VAS） questionnaires. Results The mean SF-36 subscale scores at follow-up were physical functioning 40.8 ± 26.3, role physical functioning 67.7 ± 34.9, vitality 54.6 ± 21.6, general health 52.1 ± 20.4, social functioning 63.8 ± 37.7, role emotional functioning 70.2 ± 36.0, mental health 73.2 ± 23.3 and bodily pain 80.9 ± 22.9. The mean EQ-VAS score 〉 4 years after TAVI was 64.7 ± 15.1. With respect to functional class, 80% of the patients were in NYHA class I/II at follow-up compared to 15% prior to TAVI. Conclusions This sub-study reports a significant improvement in functional class （NYHA） in a selected group of very elderly patients 〉 4 years after TAVI. Furthermore, all patients showed a satisfactory QoL despite their age and multiple comorbidities. In addition, our study reveals a lower QoL when compared with the general age matched Dutch population.

High precise control method for a new type of Piezoelectric electro-hydraulic servo valve

A new type of piezoelectric electro-hydraulic servo valve system was proposed. And then multilayer piezoelectric actuator based on new piezoelectric ceramic material was used as the electricity-machine converter of the proposed piezoelectric electro-hydraulic servo valve. The proposed piezoelectric electro-hydraulic servo valve has ascendant performance compared with conventional ones. But the system is of high nonlinearity and uncertainty, it cannot achieve favorable control performance by conventional control method. To develop an efficient way to control piezoelectric electro-hydraulic servo valve system, a high-precise fuzzy control method with hysteresis nonlinear model in feedforward loop was proposed. The control method is separated into two parts: a feedforward loop with Preisach hysteresis nonlinear model and a feedback loop with high-precise fuzzy control. Experimental results show that the hysteresis loop and the maximum output hysteresis by the PID control method are 4.22% and 2.11 μm, respectively; the hysteresis loop and the maximum output hysteresis by the proposed control method respectively are 0.74% and 0.37 μm, respectively; the maximum tracking error by the PID control method for sine wave reference signal is about 5.02%, the maximum tracking error by the proposed control method for sine wave reference signal is about 0.85%.

The role of echocardiography and CT angiography in transcatheter aortic valve implantation patients

The transcatheter aortic valve implantation （TAVI） consist an altemative treatment in patients with severe aortic stenosis. Multimodality imaging using transthoracic echocardiography （TTE） or transesophageal echocardiography （TOE） and multislice CT （MSCT） constitute cornerstone techniques for the pre-operative management, peri-procedural guidance, follow up and recognition of possible transcatheter valve related complications. CT angiography is much more accurate regarding the total definition of aortic annulus diameter and circumferential area. Two-dimensional （2D） echocardiography, underestimates the aortic valve annulus diameter compared to 3D imaging techniques （MSCT, MRI and 3D TOE）. Three-dimensional TOE imaging provides measurements of the aortic valve annulus similar to those delivered by MSCT. The pre-procedural MSCT constitutes the gold standard modality minimizing the presence of paravalvular aortic regurgitation, one of the most frequent complications. TOE/TTE and MSCT performance could predict the possibility of pacemaker implantation post-procedural. The presence of a new transient or persisting MR can be assessed well by TOE. Both TTE and TOE, consist initially the basic examination for post TAVI evaluation. In case of transcatheter heart valve failure, the MSCT could be used as additional imaging technique.

Transmural dispersion of repolarization：a complementary index for cardiac inhomogeneity

We read the article written by Nuis, et al. The authors investigated the effects of transcatheter aortic valve implantation （TAVI） on corrected QT dispersion （cQTD） in severe aortic stenosis patients. They concluded that, 40% of patients had defective cQTD recovery at six months after the procedure and this was associated with increased late mortality risk. We would like to contribute to the study from a different methodological perspective.

Early mortality and safety after transcatheter aortic valve replacement using the SAPIEN 3 in nonagenarians

Background Transcatheter aortic valve replacement （TAVR） has been performed for many elderly patients with severe aortic stenosis （AS）. The SAPIEN 3 is one of the latest balloon-expandable prosthesis. This study aimed to investigate the early clinical outcomes after TAVR using the SAPIEN 3 in nonagenarians. Methods A total of 97 consecutive patients underwent TAVR for severe AS between De- cember 2015 and December 2016. Of these, 85 consecutive patients who underwent TAVR using the SAPIEN 3 were included. According to the age, patients were classified into age 〉 90 years group （17 patients） or age 〈 90 years group （68 patients）. The clinical outcomes in- cluding all-cause mortality and composite endpoint of early safety at 30 days were evaluated. Results The Society of Thoracic Surgeons score in age 〉 90 years group was higher than age 〈 90 years group （12.3 ±6.1% vs. 8.5 ± 5.1%, P 〈 0.01）. There was no significant difference in 30-day mortality between the two groups. However, the life-threatening bleeding and major vascular complications in age 〉 90 years group were greater than age 〈 90 years group （11.8% vs. 1.5%, P = 0.04 and 11.8% vs. 1.5%, P = 0.04, respectively）. The composite endpoint of early safety at 30 days was similar between the two groups. Multivariate logistic regression analysis showed that prior myocardial infarction was an independent predictor of the composite endpoint of early safety （odds ratio： 4.76, 95% confidence interval： 1.02-22.21, P = 0.047）. Conclusions The early mortality and safety after TAVR using the SAPIEN 3 in nonagenarians were similar and acceptable despite of higher operative risk.

Comparison of in-hospital outcomes between octogenarians and nonagenarians undergoing transcatheter aortic valve replacement： a propensity matched analysis

Background Aortic valve stenosis （AS） is very common in the elderly patients above 80 years. Transcatheter aortic valve replacement （TAVR） in such patients is being increasingly performed. This study sought to assess in-hospital outcome differences between octogenarians and nonagenarians and predictors of mortality in nonagenarians undergoing TAVR with severe AS. Method The study population was derived from the National Inpatient Sample （MS） for the years 2012-2014 using ICD-9 CM procedure codes 35.05 and 35.06 for TAVR. Hospitalizations below 80 years of age were excluded. After performing propensity score matching （1： 2）, in-hospital outcomes were compared in matched cohorts. Then, multivariate model was developed to analyze predictors of in-hospital mortality in nonagenarians. Results There were 11,630 hospitalizations in the octogenarian and 5815 hospitalizations in the nonagenarian group. Primary outcome of in-hospital mortality （6% vs. 4.1%, P ≤ 0.001） was higher in nonagenarians compared to octogenarians. Secondary outcomes including stroke （3.4% vs. 2.8%, P ≤ 0.001）, renal failure （18.9% vs. 17.3%, P ≤0.001）, blood transfusion （35% vs. 32.6%, P ≤ 0.001）, vascular complications （4.5% vs. 3.5%, P ≤ 0.001）, and pacemaker implantation （27.8% vs. 24.8%, P ≤ 0.001） were higher in nonagenarians. There was no difference in their length of stay. Median cost （70,3745 vs. 65,3815, P ≤ 0.001） was slightly higher with nonagenarian. Conclusions Although in-hospital mortality is slightly higher in nonagenarians, it is acceptable. This difference in mortality is at least partly explained by higher complications in nonagenarians. Efforts should be made to decrease the complications which can further narrow the difference in in-hospital mortality between the groups.

Use of the reported Edmonton frail scale in the assessment of patients for transcatheter aortic valve replacement： a possible selection tool in very high-risk patients？

Transcatheter aortic valve replacement （TAVR） has revolutionised the treatment of patients with aortic stenosis （AS） over the last 15 years.TAVR is a well-established procedure for the treatment of patients considered high risk for open surgery. Results from the PARTNER （Placement of AoRTic traNscathetER） trial showed that inoperable patients randomly assigned to TAVR, had a 20% reduction in all-cause mortality, as well as hospitalisation, at one year compared to best medical management.

Incidence, pathophysiology, predictive factors and prognostic implications of new onset atrial fibrillation following transcatheter aortic valve implantation

1 Introduction Atrial fibrillation （AF） constitutes the most frequent cardiac arrhythmia with an increasing prevalence and incidence in the general population, demonstrating a significant impact on cardiovascular morbidity and mortality. AF has been correlated with an increased risk of stroke, systemic embolism and long term morbidity compared to individuals with sinus rhythm. The highest prevalence of AF is reported in elderly as well as in patients with severe aortic stenosis, ranging between 16% and 40% in the latter. In the general population, AF scales the death risk up to 1.5 and 1.9 fold in men and women, respectively,

Repetitive narrow QRS tachycardia in a 61-year-old female patient with recent palpitations

A 61-year-old female patient suffering from recent onset palpitations and dyspnea on exertion with hypertension and mitral valve prolapse in her past history came to our outpatient department. Echocardiography revealed a mild mitral valve prolapse, slightly decreased left ventricular （LV） function （LV ejection fraction： 51%） and a mild mitral regurgitation.

Nonlinear Modeling of a High Precision Servo Injection Molding Machine Including Novel Molding Approach

A nonlinear mathematical model of the injection molding process for electrohydraulic servo injection molding machine (IMM) is developed.It was found necessary to consider the characteristics of asymmetric cylinder for electrohydraulic servo IMM.The model is based on the dynamics of the machine including servo valve,asymmetric cylinder and screw,and the non-Newtonian flow behavior of polymer melt in injection molding is also considered.The performance of the model was evaluated based on novel approach of molding - injection and compress molding,and the results of simulation and experimental data demonstrate the effectiveness of the model.

Model-based trajectory tracking control for an electrohydraulic lifting system with valve compensation strategy

The natural frequency of the electrohydraulic system in mobile machinery is always very low,which brings difficulties to the controller design.To improve the tracking performance of the hydraulic system,mathematical modeling of the electrohydraulic lifting system and the rubber hose was accomplished according to an electrohydraulic lifting test rig built in the laboratory.Then,valve compensation strategy,including spool opening compensation (SOC) and dead zone compensation (DZC),was designed based on the flow-pressure characteristic of a closed-centered proportional valve.Comparative experiments on point-to-point trajectory tracking between a proportional controller with the proposed compensations and a traditional PI controller were conducted.Experiment results show that the maximal absolute values of the tracking error are reduced from 0.039 m to 0.019 m for the slow point-to-point motion trajectory and from 0.085 m to 0.054 m for the fast point-to-point motion trajectory with the proposed compensations.Moreover,tracking error of the proposed controller was analyzed and corresponding suggestions to reduce the tracking error were put forward.

Heart Valve Injury Induced by Mediastinum Radiotherapy in Cancer Treatment

Radiotherapy as monotherapy or in combination with chemotherapy, has contributed to the drop in mortality rates related to neoplasms in the last 60 years. However, irradiation may promote heart damage and involvement is very common. As a result, VHD （valvular heart disease） is one of the earliest cardiovascular events post-radiotherapy. What it concerns to valve disease induced by chemotherapeutics, there are still only few studies. However, patients treated with chemotherapy in combination with radiotherapy had twice the risk of developing the disease when compared to those treated by radiotherapy alone. The heart injury caused by radiotherapy begins with damage to the endothelium and results in fibrosis and diffuses calcification primarily of the mitral and aortic valves. The echocardiography is the tool of choice to the patient’s assessment and follow-up after exposure. Prevention is the best option to face the valve damage induced by radiation.

Fault Diagnosis of Reciprocating Compressors Valve Based on Cyclostationary Method

The relationship between second-order cyclostationary method and time-frequency distribution is studied, and cyclic autocorrelation（CA） function is indicated to be one sort of special time-frequency distribution method. Furthermore, a fault diagnosis method for reciprocating compressors based on empirical mode decomposition （EMD） and CA function is proposed, and then it is applied to the fault diagnosis of reciprocating compressor valve. Firstly, the vibration signal of reciprocating compressor valve is decomposed by using ENID method, and several intrinsic mode functions （IMFs） are obtained. Secondly, the IMFs are evaluated by some denoising criterions to remove the noise and interfering ones. Finally, the CA functions of the remained IMFs are calculated, which will be used to reconstruct the CA function of the original vibration signal. Engineering application indicates that this method can sufficiently inhibit the cross-interference items of CA function. Therefore, more explicit working conditions of reciprocating compressor components can be achieved.

Determination of the gas compositions for direct coal liquefaction by gas chromatography

Via multi-dimensional gas chromatography, configured with parallel dual-channel, double detectors, valves switching and back flushing, rapid analysis of the gas compositions consisting of C1-C5 hydrocarbons and permanent gases, such as CO2, H2S, H2, and CO, for direct coal liquefaction has been realized. With four packed chromatographic columns, which are Hayesep-Q pre-column, Hayesep-Q column, molecular sieve 5A column and one PLOT A1203 S capillary column, the gas compositions for direct coal liquefaction are analyzed qualitatively and quantitatively by the external standard method. The determination method has such advantages as excellent separation, simple operation, rapid analysis and accurate results.

Observations on Durability of a Pyrolytic Carbon Bileaflet Mechanical Heart Valve

This study aims to observe the durability of a pyrolytic carbon bileaflet mechanical valve prosthesis. The mechanical valves prosthesis was tested in vitro by the durability test instrument of valve prosthesis. Then in vivo, the durability of the implanted valves was observed with animal experiments and elinieal application. In the impact test for 5 min and durability test of 380 million eyeles in vitro, there was no the phenomenon of flyer, perforation and fracture observed, as well as no wear or pit found on the surface of valve leaflets. The valve leaflets could normally be turned on or off. The weight of the valve was（1.0031 ± 0.0004） g for 23 mm and（1.6003 ± 0.0002） g for 27 mm. The hydrodynamies test demonstrated that the valve prosthesis had still exeellent hemodynamic performance after the durability test. The animal autopsy showed that the valve leaflets could normally be turned on or off, and no wear was found. By follow-up of 62 patients implanted the valves, all patients had long-terms survival, no complication caused by valve was found. The age of the longest survival was more than 10 years. This study demonstrates that the new meehanieal valve prosthesis have excellent durable performance.