In order to study the condensation process of CH4-CO2 mixture gas in the supersonic nozzle, the physical and mathematical model of CH4-CO2 mixture of supersonic condensation process in the nozzle was ...given out based on the gas-liquid two-phase flow control equation, droplet nucleation, growth model and CO2 droplet surface tension. The effects of inlet pressure, inlet temperature and inlet CO2 fraction on the flow and condensation parameters were investigated. The results confirm the feasibility of using the supersonic separator for the removal of CO2 from natural gas. With the increase of the inlet pressure and the decrease of the inlet temperature, the condensation position moves forward, the maximum nucleation rate decreases and the liquid fraction of CO2 increases. The increase of inlet CO2 fraction makes it easier to achieve spontaneous condensation but the liquefaction efficiency remains at 57%~58%. The liquefaction efficiency of CO2 in the supersonic nozzle can be improved by increasing the inlet pressure and decreasing the inlet temperature.
Flow and condensation parameters distribution in the nozzle (a) temperature; (b) pressure; (c) droplet radius; (d) nucleation rate; (e) liquid fraction; (f) droplet number. Display omitted
•Mathematical model of CH4-CO2 supersonic condensation process was established.•Flow and condensation characteristics of CH4-CO2 were numerically simulated.•Influences of inlet conditions on the CO2 condensation characteristics were studied.•Methods of improving the liquefaction efficiency of the nozzle were put forward.
Triclocarban (TCC) is a highly effective antibacterial agent, which is widely used in a variety of applications and present at significant levels (e.g., 760 μg/L) in wastewater worldwide. However, ...the interaction between TCC and nitrifiers, important microbial cultures in wastewater treatment plants, has not been documented. This work therefore aimed to evaluate the fate of TCC in a nitrifying culture and its impact on nitrifiers in four long-term nitrifiers-rich reactors, which received synthetic wastewater containing 0, 0.1, 1, or 5 mg/L TCC. Experimental results showed that 36.7%–50.7% of wastewater TCC was removed by nitrifying cultures in stable operation. Mass balance analysis revealed that the removal of TCC was mainly achieved through adsorption rather than biodegradation. Adsorption kinetic analysis indicated that inhomogeneous multilayer adsorption was responsible for the removal while fourier transform infrared spectroscopy indicated that several functional groups such as hydroxyl, amide and polysaccharide seemed to be the main adsorption sites. The adsorbed TCC significantly deteriorated settleability and performance of nitrifying cultures. With an increase of influent TCC from 0 to 5 mg/L, reactor volatile suspended solids and effluent nitrate decreased from 1200 ± 90 mg/L and 300.81 ± 7.52 mg/L to 880 ± 80 and 7.35 ± 4.62 mg/L while effluent ammonium and nitrite increased from 0.41 ± 0.03 and 0.45 ± 0.23 mg/L to104.65 ± 3.46 and 182.06 ± 7.54 mg/L, respectively. TCC increased the extracellular polymeric substances of nitrifying cultures, inhibited the specific activities of nitrifiers, and altered the abundance of nitrifiers especially Nitrospira sp.. In particular, TCC at environmentally relevant concentration (i.e., 0.1 mg/L) significantly inhibited NOB activity and reduced NOB population.
Display omitted
•Nitrifying cultures removed TCC mainly by inhomogeneous multilayer adsorption.•Hydroxyl, amide and polysaccharide seemed to be the main adsorption sites.•TCC significantly deteriorated settleability and performance of nitrifying cultures.•TCC inhibited nitrifiers especially Nitrospira sp.
Cadmium (Cd) is a toxic metal capable of damaging brain. Studies have demonstrated that Cd can induce apoptosis in neuronal cells. The CD95/APO-1 (Fas)/Fas Ligand (FasL) signaling pathway is one of ...the primary apoptosis pathways, but the role and regulatory mechanism of this pathway in neuronal cells remain unclear. Here, we demonstrated the underlying mechanism of the Fas/FasL system involving the mitochondrial apoptotic pathway in neuronal cells. Primary rat cerebral cortical neurons and PC12 cells were exposed to Cd, which significantly activated expression of Fas, FasL, Fas-associated death domain (FADD) and cleaved caspase-8. However, expression of cleaved caspase-8 decreased at 20 µM Cd in primary cerebral cortical neurons. Importantly, Cd-induced apoptotic morphological changes and increase in the apoptosis rate were partially blocked by Z-IETD-FMK, which is a specific inhibitor of caspase-8. Cd-mediated increase of apoptosis rate was inhibited by anti-FasL antibody. Furthermore, our data revealed that Z-IETD-FMK also blocked increase of truncated BH3 interacting domain death agonist (tBID)/BID, decrease of the B-cell lymphoma 2 (Bcl-2)/Bcl-2 associate X protein (Bax) ratio and mitochondrial membrane potential (MMP), release of cytochrome c, as well as cleavage of caspase-9/3 and poly (ADP-ribose) polymerase (PARP) induced by Cd. Taken together, our results demonstrate that the Fas/FasL-mediated mitochondrial apoptotic pathway plays an important role in Cd-induced neuronal apoptosis.
A conical winding formation and tension control system was proposed in the doubling operation based on the yarn guide mode of a single spindle in this study. Conical winding formation realized the ...radial unwinding of wound package. An overfeed mechanism was introduced to achieve closed-loop control of yarn tension. The overfeed wheel was driven by a brushless Direct Current motor. The tension control system combined a Proportion Integration Differentiation controller with a radial-basis-function neural network, whose purpose was to meet the control requirements of the brushless DC motor. This system consisted of three main steps: Firstly, the radial-basis-function neural network was used to identify the system online. Secondly, the gradient descent method was used to adjust the node weight, center vector, and baseband width. Finally, incremental PID parameters online were adjusted according to the identified Jacobian information. A mathematical model of a control system was established in Matrix Laboratory. An experimental platform was designed for doubling winder to compare the control effects of Radial-basis-function-PID with traditional PID. The simulation results showed that the RBF-PID had a smaller overshoot of yarn tension, shorter adjustment time, and smaller steady-state error compared with the traditional PID controller in doubling operation by simulating the mathematical model. Experimental results showed the RBF-PID controller had good performance and stability and could be applied to yarns with different average linear velocity, yarn counts and strands . The yarn tension fluctuation will not exceed ±3% of the target value when the experimental materials and the cone angles are unchanged.
We report a case of non-bacterial cystitis after treatment with programmed death-1 (PD-1) and programmed cell death-ligand 1 (PD-L1) antibodies, which was considered an immune-related adverse event ...(irAE). A 48-year-old male patient with intrahepatic cholangiocarcinoma (ICC) was treated with nivolumab after postoperative multi-line treatment. This patient recurred worsening of psoriasis and repeated urinary tract discomfort. The drug was discontinued and surgery was performed due to the recurrence of the tumor suggested by imaging. After receiving three cycles of chemotherapy treatment combined with atezolizumab, urinary tract discomfort reappeared. No bacteria were found in multiple urine cultures, and non-bacterial bladder inflammation was considered after cystoscopy biopsy. This is a report of non-bacterial inflammation of the urinary tract caused by immunotherapy.
The assembly of oligopeptide and polypeptide molecules can reconstruct various ordered advanced structures through intermolecular interactions to achieve protein-like biofunction. Here, we develop a ..."molecular velcro"-inspired peptide and gelatin co-assembly strategy, in which amphiphilic supramolecular tripeptides are attached to the molecular chain of gelatin methacryloyl via intra-/intermolecular interactions. We perform molecular docking and dynamics simulations to demonstrate the feasibility of this strategy and reveal the advanced structural transition of the co-assembled hydrogel, which brings more ordered β-sheet content and 10-fold or more compressive strength improvement. We conduct transcriptome analysis to reveal the role of co-assembled hydrogel in promoting cell proliferation and chondrogenic differentiation. Subcutaneous implantation evaluation confirms considerably reduced inflammatory responses and immunogenicity in comparison with type I collagen. We demonstrate that bone mesenchymal stem cells-laden co-assembled hydrogel can be stably fixed in rabbit knee joint defects by photocuring, which significantly facilitates hyaline cartilage regeneration after three months. This co-assembly strategy provides an approach for developing cartilage regenerative biomaterials.
•First endoscopic imaging challenge on multi-instance segmentation.•>10,000 annotated images from three different surgery types.•Three-stage validation with increasing domain gap between training and ...test data.•Performance of algorithms substantially worse compared to binary segmentation.•Multi-instance segmentation of small, closely spaced and crossing instruments remains challenging.
Display omitted
Intraoperative tracking of laparoscopic instruments is often a prerequisite for computer and robotic-assisted interventions. While numerous methods for detecting, segmenting and tracking of medical instruments based on endoscopic video images have been proposed in the literature, key limitations remain to be addressed: Firstly, robustness, that is, the reliable performance of state-of-the-art methods when run on challenging images (e.g. in the presence of blood, smoke or motion artifacts). Secondly, generalization; algorithms trained for a specific intervention in a specific hospital should generalize to other interventions or institutions.
In an effort to promote solutions for these limitations, we organized the Robust Medical Instrument Segmentation (ROBUST-MIS) challenge as an international benchmarking competition with a specific focus on the robustness and generalization capabilities of algorithms. For the first time in the field of endoscopic image processing, our challenge included a task on binary segmentation and also addressed multi-instance detection and segmentation. The challenge was based on a surgical data set comprising 10,040 annotated images acquired from a total of 30 surgical procedures from three different types of surgery. The validation of the competing methods for the three tasks (binary segmentation, multi-instance detection and multi-instance segmentation) was performed in three different stages with an increasing domain gap between the training and the test data. The results confirm the initial hypothesis, namely that algorithm performance degrades with an increasing domain gap. While the average detection and segmentation quality of the best-performing algorithms is high, future research should concentrate on detection and segmentation of small, crossing, moving and transparent instrument(s) (parts).
The hydraulic joint is the key driving component of a robot. To reduce the joint size of the hydraulic robot, and improve the control accuracy and dynamic response performance, this paper proposes a ...novel joint structure and control method of a ball double-screw hydraulic robot. Using ball and circular arc spiral groove transmission, the hydraulic joint has a small transmission friction coefficient, compact overall structure and higher transmission accuracy. Aiming to resolve the problems of low control accuracy and motion instability caused by temperature drift in valve-controlled hydraulic systems, the high-precision joint control method based on adaptive fuzzy control compensation is used to improve the control accuracy and stability. The static and dynamic characteristics of the designed hydraulic joint are analyzed by simulation. A test platform was built, and the physical prototype of the hydraulic joint underwent static testing, dynamic control, amplitude frequency response and trajectory tracking tests. The experimental results were similar to the simulation results. The ball double-screw hydraulic robot joint has the characteristics of low starting pressure, high energy density, fast dynamic response, small amplitude frequency attenuation and high control accuracy. The starting pressure is 0.5 MPa, maximum swing frequency is 3 Hz, positioning accuracy is ± 0.03°, tracking accuracy is ± 3.9° and maximum angular velocity at 10 MPa is about 7.6 rad/s, which is close to the angular velocity of the actual human joint.
PDF
