Experimental Study on Chloride Ion Diffusion in Concrete under Uniaxial and Biaxial Sustained Stress.

The existence of axial and lateral compressive stress affect the diffusion of chloride ions in concrete will lead to the performance degradation of concrete structure. This paper experimentally studied the chloride diffusivity properties of uniaxial and biaxial sustained compressive stress under one-dimensional chloride solution erosion. The influence of different sustained compressive stress states on chloride ion diffusivity is evaluated by testing chloride concentration in concrete. The experiment results show that the existence of sustained compressive stress does not always inhibit the diffusion of chloride ions in concrete, and the numerical value of sustained compressive stress level can affect the diffusion law of chloride ions in concrete. It is found that the chloride concentration decreases most when the lateral compressive stress level is close to 0.15 times the compressive strength of concrete. In addition, the sustained compressive stress has a significant effect on chloride ion diffusion of concrete with high water/cement ratio. Then, the chloride diffusion coefficient model under uniaxial and biaxial sustained compressive stress is established based on the apparent chloride diffusion coefficient. Finally, the results demonstrate that the chloride diffusion coefficient model is reasonable and feasible by comparing the experimental data in the opening literature with the calculated values from the developed model.

[Treatment of central nervous system leukemia with CD19-chimeric antigen receptor T-cell immunotherapy: two cases report and literature review].

Objective: To explore the efficacy and safety of chimeric antigen receptor T (CAR-T) cells in the treatment of central nervous system leukemia (CNSL). Methods: Two leukemia patients with CNSL were treated with CD19-CAR-T cells. The process and results of the entire treatment is reported and related literature review is conducted. Results: The patients were diagnosed as acute myeloid leukemia (AML)-M(2) with B lymphoid antigen expression and B cell acute lymphoblastic leukemia(B-ALL) by morphology and immunophenotype assay. The immunophenotype was consistent with the abnormal manifestations of AML-M(2) and B-ALL. Their clinical manifestations and laboratory tests met the diagnostic criteria of CNSL. The diagnosis was clear and the two patients were treated with CD19-CAR-T cell immunotherapy. Central nervous system symptoms were relieved. The imaging abnormalities of patient one has disappeared but cytokines release syndrome (CRS) occurred during the treatment. Cerebrospinal fluid of patient two was negative and no obvious CRS reaction was found. Conclusions: CAR-T cell immunotherapy is likely to induce the remission of CNSL and improve the prognosis.

[Calculating the Hausdorff distance based on the scripting in RayStation treatment planning system].

Objective: To calculate out the Hausdorff distance based on the scripting in RayStation treatment planning system, which was then applied in measuring the deformation error of brain stem during image automatic registration between CT and MR. Methods: Scripting was edited in RayStation system (version 4.7) by using IronPython. The set of point coordinates on the contour of any two region of interest (ROI) had been found firstly, then the Hausdorff distance between the two point sets was calculated out. A graphical user interface (GUI) was designed by using XAML to acquire the visualized output of Hausdorff distance. GUI appeared when the script was run, where two ROIs was selected, then the corresponding Hausdorff distance and the running time were displayed by pressing the "Calculate" button. Results: The mean Hausdorff distance of brain stem in 20 patients with head and neck neoplasms was 1.20 cm while the mean elapsed time was 11.01s. Conclusions: Hausdorff distance of any two ROIs can be calculated out by using the developed method. GUI is designed to realize the visual interaction with RayStation system. Therefore, the RayStation system satisfies the demands of Hausdorff distance calculation in both clinical and research work.

Instrumentation design for bridge scour monitoring using fiber Bragg grating sensors.

Scour is one of the main causes of bridge failures. In order to measure and monitor scour depth variations including deposition (refilling) process, three designs for a scour monitoring system using fiber Bragg grating (FBG) sensors are discussed in the present study. By a comparative study, one of them is recommended in the present study and its instrumentation manufacture process is also introduced in detail. Using this recommended design, the advantages of FBG sensors for monitoring, such as immunity from electromagnetic interference and multiplexing capability, can be fully utilized. Both scour depth variations and entire scour development process including deposition process can be correctly monitored in real-time by continuously identifying the locations of emerging FBG sensors from the riverbed. A reliable sensor protection measure is also designed for FBG sensors in harsh environments, especially in floods. Finally, a verification test using a flume is carried out in the laboratory and three experimental cases are conducted to demonstrate the capability of FBG sensors and applicability of the recommended scour monitoring system. It can be concluded that the recommended scour monitoring system using FBG sensors is capable of measuring the water level, (maximum) scour depth, entire process of scour development, and deposition height due to refilling process. The advantages over other conventional scour monitoring systems are clearly demonstrated.

Seismic damage identification for steel structures using distributed fiber optics.

A distributed fiber optic monitoring methodology based on optic time domain reflectometry technology is developed for seismic damage identification of steel structures. Epoxy with a strength closely associated to a specified structure damage state is used for bonding zigzagged configured optic fibers on the surfaces of the structure. Sensing the local deformation of the structure, the epoxy modulates the signal change within the optic fiber in response to the damage state of the structure. A monotonic loading test is conducted on a steel specimen installed with the proposed sensing system using selected epoxy that will crack at the designated strain level, which indicates the damage of the steel structure. Then, using the selected epoxy, a varying degree of cyclic loading amplitudes, which is associated with different damage states, is applied on a second specimen. The test results show that the specimen's damage can be identified by the optic sensors, and its maximum local deformation can be recorded by the sensing system; moreover, the damage evolution can also be identified.