Objective To identify the cytokine biomarker candidates in serum associated with ionizing radiation dose, and analyze the patterns of them by cytokine antibody array. Methods Eighty male C57BL/6 mice were randomly divided into radiation group (n=60) and control group (n=20). Mice in radiation group were treated with 60Co total-body irradiation with the dose of 3, 5 and 10Gy, respectively (20 each dose group). Six hours after radiation, blood was obtained from the orbital sinus bleeding, and serums were collected. The serum cytokine concentration was analyzed by antibody array of 96 mouse cytokines, and cytokine biomarker candidates which were shown to be dose-responsive to ionizing radiation had been identified. Results Interestingly, the majority of the 96 mouse cytokines showed positive changes in amounts of cytokine. Following ionizing radiation exposure, only 44 cytokines changed at the expose dose of 3Gy, while 47 cytokines changed at the dose of 5Gy and 66 cytokines at the dose of 10Gy. Further analysis revealed that 14 cytokines were shown to be dose-responsive to ionizing radiation. Among those, 7 cytokines were shown up-regulated in a dose-dependent trend in response to ionizing radiation, and 7 cytokines were shown downregulated. Conclusion These serum cytokine biomarkers which are sensitive to ionizing radiation may act in a dose-dependent manner, suggesting that the serum cytokine biomarker candidates can be used for estimating dose of ionizing radiation.
DOI: 10.11855/j.issn.0577-7402.2013.10.008
Geological hazards such as instability of surrounding rock and leakage of water are easily occurred in subway tunnels crossing water rich sand layers. Based on the principle of fluid solid coupling in porous media, this paper studies the plastic zone distribution of surrounding rock and reinforcement ring, vertical settlement of tunnel vault and water seepage of tunnel before and after grouting reinforcement for water rich sand layer. Considering the compressibility of rock mass, the relationship between porosity, permeability and volume strain is further deduced and simplified. A set of numerical calculation formula is set up to study the change of physical parameters of the water rich sand layer before and after grouting to determine the grouting effect and select the thickness of the best grouting reinforcement ring. The results show that the deformation and water permeability of the tunnel decrease with the increase of the thickness of the grouting reinforcement ring. The thickness of the grouting reinforcement ring is the most reasonable when the thickness of the reinforcing ring reaches a certain value, and the thickness of the grouting reinforcement ring is designed to be 5~6m. The research results have been successfully applied in the grouting project of Qingdao Metro stone elderly bathing beach. The reliability of the numerical simulation is verified by comparing the data from the field monitoring and measurement, providing reference for the related projects.
When the TBM passes through the weak and broken strata, it is easy to get stuck and be buried. Through the advance pre grouting engineering practice of TBM crossing fault zone in Qingdao area, the pre grouting reinforcement measures for preventing the occurrence of TBM card machine are explored, including grouting pressure, grouting drilling design, grouting material and other key parameters. The research results show that the surface pre grouting method is an effective grouting measure to prevent the occurrence of TBM stuck and buried accidents. Single cement slurry and C-S double slurry are used as grouting materials. The cement slurry is used to fill the void in soft broken stratum and C-S double slurry is used to improve the controllability of slurry diffusion. In the process of advanced pre-grouting construction on the ground surface, the application of progressive segmental grouting technology and membrane bag sealing grouting technology can effectively guarantee the strengthening range of soft ground and improve the effect of grouting reinforcement.
Abstract A strongly weathered stratum needs to be reinforced by grouting before tunnel excavation due to its poor self-stability. This work studied the law of surface uplift caused by grouting in a strongly weathered stratum overlying a subway. A strongly weathered stratum overlying a subway section was taken as the research object, and the field test method was used to reveal the time and space variation characteristics of the surface uplift with grouting reinforcement. Then, the influence of the grouting reinforcement technology, quantity, and material on the maximum surface uplift value in the practical grouting process was analyzed. The results show the following. Regardless of whether film bag grouting is used or not, the uplift value of the monitoring points is directly proportional to time, and the growth rate of the uplift value tends to accelerate. The spatial distribution of the surface uplift is mainly related to its distance to the grouting point. In addition, the maximum uplift value of the film bag grouting technology is 32.1% lower than that of the ordinary grouting technology; given the same grouting materials and technology, the grouting amount increases by 50%, and the surface uplift value increases by 121%. Moreover, the C-S slurry exhibits rapid setting, a small diffusion range, and a large thickness of the grouting vein; the surface uplift value of the C-S slurry is 3.08 times that of the cement slurry. The field test research conclusion is applied to practical engineering, where the final uplift value is 1.8 to 2.5 cm, and the average permeability coefficient of the inspection hole is 3.52×10 −7 cm/s, which reflects a good engineering governance effect.
Urban subway construction inevitably causes disturbances to the rock strata. It can even cause ground collapse accidents when construction encounters a bad geological body in the stratum. To verify the influence of cavities on surface settlement and the mechanism of formation instability, the instability mechanism of cavity‐bearing strata under tunnel excavation disturbance was herein studied by tests using self‐designed indoor models and numerical simulations. This study was based on the concrete project case of Qingdao Metro. Two groups of experiments (with and without cavities) were designed to simulate the four‐step excavation by staged unloading of an airbag. The results show that the settlement value in the cavity state was about twice as much as that in the nonvoid state at the same stage. Besides the first step of excavation, in the numerical simulation, the settlement value of the same stage is about 1.3 times that of the model test. Simulating the deformation process of the surrounding rock in model tests shows that, in the excavation of the tunnel, the collapse surface of the tunnel arch roof will be connected with the sliding surface of the formation cavity. The cavity will gradually change from a regular circle to an ellipse or may even close, resulting in a sudden increase in land subsidence or even ground collapse. This indicates that disturbance during tunnel excavation would cause greater instability in a stratum when bad geological bodies, such as cavities, exist in the stratum.
Liquefaction has caused significant failures and represents a significant problem for the community and geotechnical engineering designers.The survey in the Chengdao sea of Yellow River Delta showed the presence of a large number of pits, geological disasters gullies, landslides, residual body and buried ancient river.In this paper, we utilize in-situ test data in Chengdao sea of Yellow River delta to analyse the nonuniformity liquefaction of the space.The results is exhibited to the vertical non-uniformity, which is located in correlation distance between 0.32~0.93m.The depth of liquefaction varies with the larger storm level, and weak interlayer is susceptible to liquefaction.
To solve the problem that the type and area of macular disease are not easy to identify due to the irregular scale and unobvious characteristics of macular disease region on retinal OCT images, an improved YOLOv8n macular disease detection model is proposed, and a data set of retinal macular disease detection is established. Firstly, the feature pyramid module of bidirectional weighted feature fusion was added. Secondly, the attention mechanism was introduced. Finally, the novel loss function was replaced. The improved model can complete the multi-scale and irregular multi-objective training task of retinal maculopathy. The experimental results show that the improved model has a good effect on the self-built data set. The accuracy of central serous macular degeneration, macular hole, and choroidal neovasculation can reach 97.7%, 97.8%, and 97.4%, respectively, and can accurately identify the location of the lesion.
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