Mitral valve regurgitation and endocarditis triggered by a needle

Abstract Background Cardiac foreign bodies are extremely rare in clinical patients, especially when foreign bodies damage the internal structure of the heart coincidentally after they penetrate the heart. Case presentation Here, we report the case of a two-year-old girl whose heart was penetrated by a needle, which triggered mitral valve regurgitation and endocarditis. After a comprehensive inspection, accurate judgment and surgical preparation, we removed the needle and repaired her mitral valve. Fortunately, she recovered postoperatively. Conclusion From this case, we can know that when cardiac foreign bodies are suspected, ultrasound is an important inspection method. Moreover, the approaches for handling each such case are different depending on the associated injuries

Compaction Quality Inspection and Uniformity Analysis of Soil-Rock Mixed Subgrade

GeoGauge is a portable instrument for rapid determination of the stiffness and modulus of compacted soil, which can quickly, safely, and nondestructively evaluate the quality of each compacted layer. In order to deeply study the effectiveness of the detection instrument and equipment used in the soil-rock mixed subgrade, based on the construction project of Beijing-Qinhuangdao Expressway, the influence of water content and compaction degree on the test results and the correlation between GeoGauge detection stiffness and settlement difference were studied and analyzed by indoor model test and field test. Finally, the subgrade compaction uniformity is evaluated according to the measured data of the test section and the predicted value obtained by the ordinary Kriging interpolation method. The results show that: The GeoGauge detection stiffness value shows a trend of first increasing and then decreasing as the water content increases. When the water content is 8%, the detection stiffness value of the earth rock mixture reaches the maximum value. There is a good exponential relationship between the compactness of soil-rock mixture and the stiffness value of GeoGauge detection, and the correlation coefficient is 0.9231, which indicates that the stability of GeoGauge detection results is high. The GeoGauge detection stiffness value increases with the increase of the number of rolling passes. When the number of rolling passes is greater than five, the increase in the detection stiffness of subgrade soil decreases, indicating that the subgrade filler has approached the compaction standard after five passes of rolling. The regression equation between GeoGauge detection stiffness value and settlement difference is established, and the specific index of subgrade stiffness is calculated according to the regression equation when the compactness meets the design conditions, which provides reference for practical engineering

Pretreatment with intraluminal rapamycin nanoparticle perfusion inhibits neointimal hyperplasia in a rabbit vein graft model

Kai Liu1*, Guangqing Cao1*, Xiquan Zhang1, Ruifang Liu2, Weiwei Zou3, Shuming Wu11Departments of Cardiovascular Surgery, 2Anesthesia, Qilu Hospital of Shandong University, Jinan; 3The School of Pharmaceutical Science, Shandong University, Jinan, Shandong, People’s Republic of China; *Kai Liu and Guangqing Cao contributed equally to this work.Purpose: Poly lactic-co-glycolic acid nanoparticles (PLGA-NP) are widely used as a biodegradable biomaterial in medicine. Rapamycin-eluting stents have been used for prevention of restenosis during surgery. This study investigated the effect of pretreatment with intraluminal perfusion of carbopol-encapsulated rapamycin-loaded PLGA nanoparticles (RAP-PLGA-NP) on neointimal hyperplasia in a rabbit vein graft model.Methods: A segment of common carotid artery was replaced with a segment of external jugular vein in 60 rabbits which were then separated into four treatment groups, ie, Group 1, in which vein grafts were pretreated with intraluminal RAP-PLGA-NP perfusion, Group 2 in which vein grafts underwent equivalent empty vehicle (PLGA-NP) perfusion, Group 3, in which vein grafts received no treatment, and Group 4, which served as a sham operation group receiving normal vein contrast. On postoperative day 28, the grafts and normal veins were harvested for histologic examination, flow cytometry analysis, and high-performance liquid chromatography measurement.Results: Compared with Group 1, the intima of the grafts were thickened, the ratio of intimal area to vessel area increased, and the collagen volume index of the vein grafts increased significantly in Groups 2 and 3. The cell proliferation index in Group 1 (21.11 ± 3.15%) was much lower than that in Group 2 (30.35 ± 2.69%) and in Group 3 (33.86 ± 8.72%). By high-performance liquid chromatography measurement, retention of rapamycin was detected in Group 1 (11.2 ± 0.37 µg/10 mg) 28 days after single drug perfusion.Conclusion: Pretreatment with intraluminal RAP-PLGA-NP perfusion may inhibit neointimal hyperplasia in vein grafts by penetrating into local tissue and limiting cell proliferation.Keywords: autograft, stenosis, jugular vein, transplant

Three-Dimensional IFE-PIC Numerical Simulation of Background Pressure\u27s Effect on Accelerator Grid Impingement Current for Ion Optics

A three-dimensional numerical simulation modeling is developed to investigate the background pressure\u27s effect on the characteristics of ion impingement on the accelerator grid for the ion optical system. The immersed-finite-element particle-in-cell (IFE-PIC) method is combined with Monte Carlo method to compute the electric field, track the ions, and describe the charge-exchange collision process while direct simulation Monte Carlo (DSMC) method is adopted to simulate the motion of neutral atoms. Results show that the residual neutral atoms in the vacuum chamber play an important role in the neutral atoms distribution when the background pressure is higher than a specific magnitude, and the accelerator grid impingement current increases with the increase of the background pressure. To improve the reliability of ion thruster service lifetime prediction in the ground life tests, the background pressure in the vacuum chamber should be below 10-3 Pa

Performance evaluation of two types of heated cables for distributed temperature sensing-based measurement of soil moisture content

Distributed temperature sensing (DTS) using heated cables has been recently developed for distributed monitoring of in-situ soil moisture content. In this method, the thermal and electrical properties of heated cables have a significant influence on the measurement accuracy of soil moisture content. In this paper, the performances of two heated cables, i.e. the carbon-fiber heated cable (CFHC) and the metal-net heated cable (MNHC), are studied in the laboratory. Their structures, uniformity in the axial direction, measurement accuracy and suitability are evaluated. The test results indicate that the MNHC has a better uniformity in the axial direction than CFHC. Both CFHC and MNHC have high measurement accuracy. The CFHC is more suitable for short-distance measurement (≤500 m), while the MNHC can be used for long-distance measurement (>500 m)

Stability Analysis and Reinforcement Management of Slope

The sliding damage occurred on a slope site due to rainfall and other environmental conditions, and the slope stability coefficient was calculated to be 1.05 based on the numerical analysis model of the slope based on the site investigation data, which did not meet the reinforcement requirements of the code. The slope stability coefficient after reinforcement is 1.39, which is 32.4% higher than that before reinforcement, indicating that the reinforcement scheme is feasible

A distributed measurement method for in-situ soil moisture content by using carbon-fiber heated cable

Moisture content is a fundamental physical index that quantifies soil property and is closely associated with the hydrological, ecological and engineering behaviors of soil. To measure in-situ soil moisture contents, a distributed measurement system for in-situ soil moisture content (SM-DTS) is introduced. The system is based on carbon-fiber heated cable (CFHC) technology that has been developed to enhance the measuring accuracy of in-situ soil moisture content. Using CFHC technique, a temperature characteristic value (Tt) can be defined from temperature–time curves. A relationship among Tt, soil thermal impedance coefficient and soil moisture content is then established in laboratory. The feasibility of the SM-DTS technology to provide distributed measurements of in-situ soil moisture content is verified through field tests. The research reported herein indicates that the proposed SM-DTS is capable of measuring in-situ soil moisture content over long distances and large areas