Objective To investigate the prognostic value of serum amyloid A (SAA) in the patients with Corona Virus Disease 2019 (COVID-19). Methods The medical data of 89 COVID-19 patients admitted to Renmin Hospital of Wuhan University from January 3, 2020 to February 26, 2020 were collected. Eighty-nine cases were divided into survival group (53 cases) and non-survival group (36 cases) according to the results of 28-day follow-up. The SAA levels of all patients were recorded and compared on 1 day after admission (before treatment) and 3 days, 5 days, and 7 days after treatment. The ROC curve was drawn to analyze the prognosis of patients with COVID-19 by SAA. Results The difference of comparison of SAA between survival group and non-survival group before treatment was not statistically significant, Z 1 = − 1.426, P = 0.154. The Z 1 values (Z 1 is the Z value of the rank sum test) of the two groups of patients at 3 days, 5 days, and 7 days after treatment were − 5.569, − 6.967, and − 7.542, respectively. The P values were all less than 0.001, and the difference was statistically significant. The ROC curve results showed that SAA has higher sensitivity to the prognostic value of 1 day (before treatment), 3 days, 5 days, and 7 days after treatment, with values of 0.806, 0.972, 0.861, and 0.961, respectively. Compared with SAA on the 7th day and C-reactive protein, leukocyte count, neutrophil count, lymphocyte count, and hemoglobin on the 7th day, the sensitivities were: 96.1%, 83.3%, 88.3%, 83.3%, 67.9%, and 83.0%, respectively, of which SAA has the highest sensitivity. Conclusion SAA can be used as a predictor of the prognosis in patients with COVID-19.

In order to investigate flexural behavior of simply-supported beam using recycled coarse aggregate concrete, the difference of the component normal section stress distortion performance and failure characteristic between the recycled concrete beam and the normal concrete beam is researched. The approaches of testing the flexural behavior of 6 recycled course aggregate beams with the same section size, different replacement ratio of recycled coarse aggregate (0%, 50%, 70% and 100%) and different percentage reinforcement (0.68%, 0.89% and 1.13%). Based on the experimental the following conclusions are draw. There are also 4 phases of elasticity, cracking, yield and ultimate during the stress course of recycled concrete beam component normal section stress; the average strain measured on cross-section obliges to the plane section assumption; the characteristics of stress distortion and destruction of recycled concrete beam are basically the same as those of the normal concrete beam. Under same conditions, the cracking moment and the ultimate flexural carrying capability of recycled concrete beam is almost the same as those of normal concrete beam. The deformation of recycled concrete beam is larger than concrete beam. The conclusion of the paper is that it is still feasible to calculate the ultimate bending moment, cracking moment, and the biggest crack width of recycled concrete beam according to the formula in China Concrete Structure Design Code, but the deflection formula needs to be adjusted.

The optothermal manipulation of micro-objects is significant for understanding and exploring the unknown in the microscale word, which has found many applications in colloidal science and life science. In this work, we study the transverse forces of an optothermal trap in front of a gold film, which is an absorbing reflective surface for the incident laser beam. It is demonstrated that optothermal forces can be divided into two parts: optical force of a standing-wave trap, and thermal force of a thermal trap. The optical force of the standing-wave trap can be obtained by measuring the optical trapping force close to a non-absorbing film with same reflectance. The thermal force can be obtained by subtracting the optical force of the standing-wave trap from the total trapping force of the optothermal trap close to the gold film. The results show that both optical and thermal trapping forces increase with laser power increasing. The optical trapping force is larger than the thermal trapping force, which is composed of convective drag force and thermophoretic force. Further experiment is run to study the composition of thermal force. The result shows that the convective flow is generated later than the thermophoretic flow. The results proposed here are useful for enabling users to optimize optothermal manipulation method for future applications.

The photothermal effects have shown the possibilities for applications in optical manipulation. In this paper, an approach is demonstrated to generate and manipulate a bubble using the photothermal effects. First, a high-power laser is used to irradiate the light absorbing particles for creating a microbubble. The bubble grows up to a diameter of a few hundred micrometers in several seconds due to the diffusion of dissolved gases. The bubble does not float up and is confined at the lower boundary of the sample cell by the thermocapillary force. The force is induced by laser heating of the particles at the bubble base. Second, the bubble can be manipulated following the laser focal spot. The bubble is dragged by the horizontal component of thermocapillary force. The bubble re-grows as it moves because it absorbs the dissolved gases in its migration path. The bubble floats up finally when it grows up to the maximum size. The perpendicular component of thermocapillary force can be estimated equal to the buoyancy of the floated bubble and is about 38 nN at the laser power of 130 mW. Furthermore, we show the generation and manipulation of the bubbles in a capillary. The reason for the decrease in movement velocity in the capillaries has been studied and discussed. The approach of bubble manipulation shows a potential application in transporting the microparticles.

The ability to trap and rotate magnetic particles has important applications in biophysical research and optical micromachines. However, it is difficult to achieve the spin rotation of magnetic particles with optical tweezers due to the limit in transferring spin angular momentum of light. Here, we propose a method to obtain controlled spin rotation of a magnetic microparticle by the phoretic torque, which is originated from inhomogeneous heating of the microparticle’s surface. The microparticle is trapped and rotated nearby the laser focus center. The rotation frequency is several Hertz and can be controlled by adjusting the laser power. Our work provides a method to the study of optical rotation of microscopic magnetic particles, which will push toward both translational and rotational manipulation of the microparticles simultaneously in a single optical trap.