[Comparison of early outcome between one-stage hybrid technique and frozen elephant thunk technique in the treatment of Stanford A aortic dissection involving the arch]

Objective: To analyze the early outcome of one-stage hybrid technique in the treatment of Stanford type-A aortic dissection involving the arch and compare its therapeutic efficacy with the classical frozen elephant trunk technique (FET). Methods: A total of 106 patients with Stanford type-A aortic dissection involving the arch in Department of Cardiac and Vascular Surgery, 1st Affiliated Hospital of Soochow University from October 2015 to October 2019 was collected. All patients in this group were treated with one-stage hybrid technique (modified arch debranching technique) without deep hypothermia circulation. Meanwhile, 30 patients with Stanford type A dissection involving the arch who underwent FET from January 2014 to September 2015 were collected. The therapeutic effects of the two surgical methods were analyzed and compared. Results: The age [M (Q₁, Q₃)] of 106 patients in hybrid group was 49.0 (40.0, 55.0) years, including 89 males and 17 females. The age [M(Q₁, Q₃)] of 30 patients in FET group was 49.5 (41.5, 65.3) years, including 24 males and 6 females. The time [M(Q₁, Q₃)] of using ventilator in hybrid group was 56.0 (38.0, 72.0) h, which was shorter than 127.0 (92.0, 145.0) h in FET group (P<0.001). The incidence of cerebral infarction in hybrid group was 2.8% (3 cases), which was lower than 13.3% (4 cases) in FET group (P=0.042); the incidence of postoperative renal insufficiency in hybrid group was 7.5% (8 cases), which was lower than 23.3% (7 cases) in FET group (P=0.023); the ICU time [M (Q₁, Q₃)] in hybrid group was 8.0 (6.0, 10.0) d, which was shorter than 14.0 (8.3, 24.0) d in FET group (P<0.001). Conclusion: Compared with FET, one-stage hybrid technology is safer and more effective in the treatment of Stanford type A aortic dissection involving the arch. Its short-term therapeutic efficacy appears good.

Synthesis and receptor dependent 4D-QSAR studies of 4,5-dihydro-1,3,4-oxadiazole derivatives targeting cannabinoid receptor

Cannabinoid receptor has been shown to be overexpressed in various types of cancers, especially non-small cell lung cancer. As a result, it could be used as novel target for anticancer treatments. Because receptor-dependent 4D-QSAR generates conformational ensemble profiles of compounds by molecular dynamics simulations at the binding site of the enzyme, this work describes the synthesis, biological activity evaluation and 4D-QSAR studies of 4,5-dihydro-1,3,4-oxadiazole derivatives targeting cannabinoid receptor. Compared with WIN55,212-2, compound 5 f showed the best antiproliferative activity. The receptor-dependent 4D-QSAR model was generated by multiple linear regression method using QSARINS. Leave-n-out cross-validation and chemical applicability domain were performed to analyse the independent test set and to verify the robustness of the model. The best 4D-QSAR model showed the following statistics: r² = 0.8487, Q²_LOO = 0.7667, Q²_LNO = 0.7524, and r²_Pred = 0.8358.

Conscious sedation and reduction of fractures in the paediatric population: an orthopaedic perspective

PURPOSE

Closed reduction under conscious sedation in the emergency department (ED) has been demonstrated to provide cost-effective, timely care. There has been little research into the efficacy of conscious sedation and reduction from an orthopaedic trauma perspective. This study describes the epidemiology and outcomes associated with fracture conscious sedation and reduction in our level I paediatric ED.

METHODS

All fracture patients presenting overnight to our level I trauma centre ED between 01 June 2016 and 30 June 2017 were identified. Patient records were reviewed to determine diagnoses, treatments and outcomes. The rate of repeat intervention after successful conscious sedation and reduction and rate of changes in management in which the orthopaedic resident's overnight management plan to provide procedural sedation was altered to surgical intervention after morning case review rounds was calculated.

RESULTS

Conscious sedation and reduction was performed on a total of 386 patients covering ten fracture types during the course of our study, with distal radius fractures (n = 167, 43.3%) comprising the majority of cases. A total of 53 cases (13.7%, 53/386) lost alignment and required repeat intervention, consisting of 33 cases (8.5%, 33/386) that required repeat surgery and 5.2% (20/386) that required cast wedging. In all, 12 patients (3.1%, 12/386) initially reduced under conscious sedation required a change in management and surgical intervention. There were five cases of growth arrest and two cases of malunion.

CONCLUSIONS

Conscious sedation and reduction provides an alternative to general anaesthesia for many paediatric trauma injuries without compromising patient outcomes.

LEVEL OF EVIDENCE

IV.

CFD evaluation on the thermohydraulic characteristics of tube support plates in steam generator

The integrity and thermal hydraulic characteristics of steam generator are of great concern in the nuclear industry. The tube support plates (TSP), one of the most important components of the steam generator, not only support the heat transfer tubes, but also affect the flow dynamic and thermal hydraulic characteristics of the secondary-side flow inside the steam generator. Different working conditions, ranging from single-phase adiabatic condition to two-phase high-void boiling condition, are simulated and analyzed. Calculated void fraction, under simple geometry, agrees well with the experiment data whilst the simulated heat transfer coefficient is tremendously close to the empirical correlation. Temperature, void fraction, and velocity distributions in different locations show reasonable distribution. The simulation results indicate that TSP can enhance the heat transfer in the secondary side of the steam generator. On the top of TSP, with the increase in cross-section flow area, the back-flow phenomenon occurs, which might lead to the contamination of precipitation.

CFD analysis on mixing effects of spacer grids with different dimples and sizes for advanced fuel assemblies

The thermal hydraulic characteristics of a mixing vane grid are largely dependent on the structure of key components, such as strip, spring, dimple, weld nugget, as well as the mixing vane configuration. In this paper, several types of spacer grids with different dimple shapes are modeled under subcooled boiling conditions. Prior to the application of CFD on the dimple shape analysis, the mixing effects of spacer grids were studied. After the dimple shape analysis, the side channel effect is discussed by comparing the simulation results of a 3 × 3 and a 5 × 5 spacer grid. The two phase flow CFD models in this study are validated through simple geometry showing that the calculated void fraction is in good agreement with the experimental data. The dimple comparison result shows that varying dimple structures can result in different temperatures, lateral velocities and void fraction distributions downstream of the spacer grids. Comparison of two sizes of spacer grids demonstrate that the side channel generates different flow distribution pattern in the center channel.

Interlayer cross talk in dual-layer read-only optical disks

Volumetric optical disks comprising multiple data layers have been proposed to multiply recording density. Owing to the presence of out-of-focus data layers, interlayer cross talk is induced in readout. An optical model was developed to study the readout process and the effect of interlayer cross talk on the readout of dual-layer read-only optical disks. Schemes to improve the readout characteristics by suppression of the interlayer cross talk were proposed. Experiments that agreed well with the simulation resulted.