Functionalized Ferroferric Oxide Nanomagnetic Beads for Extraction of Nucleic Acid and Its Application in Early Screening of Colorectal Cancer

Early screening is an important way to reduce the incidence and mortality of colorectal cancer (CRC). Fecal DNA testing stands out among many screening methods due to its high sensitivity. However, at this stage, researchers have not found a high-efficiency method for fecal DNA extraction. To this end, this work carried out a new round of exploration. Here, this experiment synthesized a kind of nanomagnetic beads (NH2-SiO2@Fe3O4) with good stability for nucleic acid extraction. A comparative study with the centrifugal adsorption column method revealed the significant advantages of the magnetic bead method in extracting fecal DNA. The DNA extracted by the magnetic bead method is of high purity, can also achieve high-throughput tests, and is more suitable for polymerase chain reaction detection, greatly simplifying the stool DNA detection process and providing a basis for the widespread promotion of early screening.

Design and development of a vortex ring generator to study the impact of the ring as a gust

ABSTRACTWe present a simple method to generate discrete aerodynamic gust under controlled laboratory condition in the form of a vortex ring which, unlike conventional methods of perturbation, is well studied and highly controllable. We characterized the flow properties of the vortex ring using flow visualization and novel light bead method. Reynolds number of the vortex ring, based on its average propagation velocity and nozzle exit diameter, was 16000. We demonstrate this method by studying the impact of head-on gust on freely flying soldier flies, Reynolds number of which, based on its wingtip velocity and mean wing chord, was 1100. We also present simple theoretical models to characterize the vortex ring based on generating conditions. The device can also be used to generate continuous gust in any direction and can be applied, in general, to study the gust response of natural fliers and swimmers, man-made micro aerial vehicles and aquatic plant lives.

The study on knee osteoarthritis in diabetic patients based on nanometric magnetic bead method

To study the levels of inflammatory cytokines in synovia fluid from osteoarthritis (OA) patients with/without type 2 diabetes mellitus (T2D). Out of 74 volunteers aged 20–88 years, 64 with knee OA (Kellgren-Lawrence grades over I) were recruited and divided into groups with (n = 20) and without (n = 44) diabetes. The nucleic acid of the patient tissue was extracted by nanometer magnetic bead method. The remaining participants were the control group (n = 10). Synovia fluid, sera, and peripheral blood mononuclear cell (PBMC) samples were collected from all participants and analyzed using ELISA Kits. T2D-OA patients and OA patients had higher basal production of interleukin-1, (IL-1), interleukin-6 (IL-6), and lower-level interleukin-10 (IL-10). However, there were no differences between T2D-OA and OA patients. IL-1, IL-10, and IL-6 in peripheral blood mononuclear cells (PBMCs) after stimulation with LPS were obviously up-regulated in both patients and controls. The production of IL-1 and IL-6 in synovia from T2D-OA and OA patients increased as in the case of variations in sera and PBMCs. Both T2D-OA and OA patients had high-levels of IL-1 and IL-6 compared with controls, especially IL-6. The presence of IL-10 could not be detected in synovia from both patients and controls. Our results suggested that OA patient also had some pro-inflammatory factors in vivo, especially in local lesion; this manifest was particularly evident in T2D-OA patients. The high-level concentration of pro-inflammatory cytokines and low-level anti-inflammatory factors could be one of the reasons why T2D-OA patients are prone to developing synovitis.

DNA extraction and sequencing of the Mawangdui ancient cadaver protected by formalin

Mawangdui ancient Cadaver is the first wet corpse found in the world, which is famous for being immortal for over two thousands of years. After being unearthed, the female corpse was immersed in the formalin protective solution for more than 40 years. We used magnetic bead method and formalin fixed paraffing (FFPE) method to extract the DNA of the female corpse, respectively. PCR amplification, sanger sequencing, library building, high throughput sequencing (testing) and data processing were carried out on the DNA samples, and about 0.5% of the whole genome coverage sequencing data was obtained. Comparing the results of DNA trough two extraction and sequencing methods. We found that the FFPE and high throughput sequencing methods is better than others for DNA extraction of the ancient samples which were preserved in formalin, providing a guidance for dealing with formalin preserved ancient samples in the future.

Axial Calibration of QPD Signal based on Stuck Bead Method for Optical Trapping Applications

Calibration of axial quadrant photodetector (QPD) signal to the trapped bead position in an optical tweezer is important to measure the quantitative mechanical parameter in axial (laser propagation) direction. An alternative calibration based on the Stuck Bead Method (SBM) was proposed in this study. 3 µm polystyrene beads were stuck at the surface of glass coverslip and moved axially around the laser focus. QPD was used to obtain the position dependent intensity profile at three different laser powers (19.8 mW, 34.1 mW, 48.5 mW). The QPD signal-to-distance calibration value was consistent at 26 mV/µm for the used bead at the three laser powers. It was found that the calibration values are independent of laser powers and limited by the resolution of distance adjustment.