Continued sustained release of VEGF by PLGA nanospheres modified BAMG stent for the anterior urethral reconstruction of rabbit

Objective:To study the biocompatibility and neovascularization of the PLGA nanospheres wrapped with vascular endothelial growth factor(VEGF).which can improve bladder acellular matrix graft(BAMG) with local continuous release of VEGF.Methods:A total of 18 rabbit model (length of stenosis:3cm) with anterior urethral stricture were used as experimental animals and divided into three groups.Group A as the control group:Simple BAMG scaffold materials for urethral reconstruction.Group B as the blank group:PLGA microspheres modified BAMG for urethral reconstruction.Group C:PLGA conjugated with VEGF and modified BAMG for the urethral reconstruction.All rabbits underwent urethral angiography after 7 days,15 days,1 month and 3 months after the operation,and one rabbit in each group was sacrificed to be prepared for the organization histologic examination,HE staining,masson staining,CD31,34 and a-SAM immunohistochemical detection in the repaired sites.Results:In group A,significant urethral restenosis occurred in two rabbits after 15 days of the operation,HE and masson staining showed a lot of collagen arranged in the repaired sites,and there were a large number of inflammatory cell infiltration,and there were also CD31,34 in the repaired sites.a-SAM microvascular tag count showed a small amount of microvascular;Croup B showed anastomotic restenosis,HE and masoon staining showed inflammatory cell infiltration and collagen deposition;Group C:urethrography showed lumen patency.There were a small amount of inflammatory cell infiltration after 7 and 15 days after the operation,and there were also CD31,34 in the repaired sites.The a-SAM microvascular tag count showed many microvascular.And the difference was significant.Conclusions:Anterior urethral reconstruction with sustained-release of VEGF by PLGA nanospheres modified BAMG stents can reduce postoperative restenosis.It can also reduce collagen deposition and scar formation,promote angiogenesis of the repair tissue;therefore it in valuable in the tissue-engineered urethral reconstruction.

Long term outcomes of saphaneous vein graft intervention in elderly patients with prior coronary artery bypass graft

Objectives To investigate the procedure characteristics and long term follow-up ofpercutaneous coronary intervention （PCI） for sa phaneous vein graft （SVG） lesions in the elderly patients. Methods From December 2005 to December 201 l, 84 graft lesions were treated percumneously. Seventeen were located at proximal anastomosis, 48 were located at SVG body, 19 were located at distal anastomosis. Pri mary endpoint was defined as major adverse cardiovascular events （MACE, composite of cardiac death, target vessel revascularization, acute myocardial infarction）. Results The graft age was 6.7 i 4.0 years. Most anastomosis lesions （80.0%） presented within one year post coro-nary artery bypass grafting （CABG）. Proximal anastomosis lesion had the lowest successful rate for PCI compared with graft body and distal anastomosis lesions （70.6% vs. 91.7%, 79.0%, P 〈 0.05）. The distal embolic protection device was used in 19.1% of patients, most frequently used in body graft PCI （29.2%, P 〈 0.01）. The diameter of the stent was smallest in distal anastomosis group （2.9 ±0.4 mm, P 〈 0.05）. The highest post dilatation pressure was required in the proximal anastomosis （17.8 ± 2.7 atm, P 〈 0.05）. The patients were followed up for 24.3 ±16.9 months. MACE occurred in 18.57% of patients. Incidence of MACE was highest among proximal anastomosis PCI （47.1% vs. body graft PCI 16.7%, distal anastomosis PCI 21.1%; P 〈 0.05）. Old myocardial infarction was the predictive factor for the poor clinical outcomes （P〈 0.04）. Conclusions PCI of SVG lesions is feasible with lower success rate. PCI of ostial graft anastomosis lesions had the lowest procedure success rate and highest MACE rate compared with graft body and distal anastomosis lesions. Old myocardial infarction was a predictive factor of poor outcomes.

Comparison of surgical intervention with functional treatment for acute ruptures of lateral ankle ligmant:a meta-analysis

Objective:To compare the effect of surgical intervention on functional treatment.Methods: By searching the MEDLINE(1966 to October 2011),EMBASE(1980 to October 2011),the Chinese Biomedical Database Databases(1980 to October 2011),a total of 9 related RCT studies comparing surgical intervention with functional treatment were included in our study.RevMan software was taken to analyze the data.Results:These 9 studies Involved a total of 1 268 mostly young adults,including 580 patients with surgical treatment and 688 patients with functional treatment.The results showed the stability of ankle activity in surgical treatment group was better than that in functional treatment group,with the OR and 95%CI of 0.72(0.52-0.99).No significant difference was found in the recurrence of the surgical and functional group.However, the movement disorder in the surgical treatment suggested increased risk than that in functional group,with the OR and 95%CI of 2 39(0.98-5.85).Surgical group found more complication than the function group,such as deep vein thrombosis,deep venous thrombosis,tenderness of scar and sensory loss.Conclusions:In conclusion,our finding showed that surgical treatment could gain better efficacy than functional treatment,but may bring more complication.Therefore,further large sample size RCT is warranted.

Real-time Control Oriented HCCI Engine Cycle-to-cycle Dynamic Modelling

For homogeneous charge compression ignition （HCCI） combustion, the auto-ignition process is very sensitive to in-cylinder conditions, including in-cylinder temperature, in-cylinder components and concentrations. Therefore, accurate control is required for reliable and efficient HCCI combustion. This paper outlines a simplified gasoline-fueled HCCI engine model implemented in Simulink environment. The model is able to run in real-time and with fixed simulation steps with the aim of cycle-to-cycle control and hardware- in-the-loop simulation. With the aim of controlling the desired amount of the trapped exhaust gas recirculation （EGR） from the previous cycle, the phase of the intake and exhaust valves and the respective profiles are designed to vary in this model. The model is able to anticipate the auto-ignition timing and the in-cylinder pressure and temperature. The validation has been conducted using a comparison of the experimental results on Ricardo Hydro engine published in a research by Tianjin University and a JAGUAR V6 HCCI test engine at the University of Birmingham. The comparison shows the typical HCCI combustion and a fair agreement between the simulation and experimental results.

Robust Stabilization of Load Frequency Control System Under Networked Environment

The deregulation of the electricity market made the open communication infrastructure an exigent need for future power system. In this scenario dedicated communication links are replaced by shared networks. These shared networks are characterized by random time delay and data loss. The random time delay and data loss may lead to system instability if they are not considered during the controller design stage. Load frequency control systems used to rely on dedicated communication links. To meet future power system challenges these dedicated networks are replaced by open communication links which makes the system stochastic. In this paper, the stochastic stabilization of load frequency control system under networked environment is investigated. The shared network is represented by three states which are governed by Markov chains. A controller synthesis method based on the stochastic stability criteria is presented in the paper. A one-area load frequency control system is chosen as case study. The effectiveness of the proposed method for the controller synthesis is tested through simulation. The derived proportion integration （PI） controller proves to be optimum where it is a compromise between compensating the random time delay effects and degrading the system dynamic performance. The range of the PI controller gains that guarantee the stochastic stability is determined. Also the range of the PI controller gains that achieve the robust stochastic stability is determined where the decay rate is used to measure the robustness of the system.

Modelling of the Whole Process of a University Campus CHP Power Plant and Dynamic Performance Study

Combined heat and power （CHP） refers to a process/system designed to utilize the waste or residual heat from a power generation process. Thus, a CHP plant can produce both electricity and heat. The nature of such a combination makes the process more complex than any single power generation process or boiler heating system. The paper focuses on modelling study and analysis of energy efficiency of the University of Warwick micro-CHP power plant. In this CHP modelling study, a gas turbine module is built to provide driving power and methane is used as fuel gas. Heat recovery system and auxiliary boiler modules are developed for thermal power generation. All the sub-systems are validated by comparing the simulation results with the operating data collected from the CHP plant. The dynamic performance of the key CHP process outputs is studied with respect to the variation of the input syngas stream, including electricity generation, thermal power output and water output temperature. Simplified controllers are also applied to the gas engineheat recovery subsystem and auxiliary boiler. Simulation results with/without feedback control are both analyzed. The study has highlighted the key factors which influence the plant performance and suggested the strategy for potential energy efficiency improvement.