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Accumulating evidence has confirmed that chronic obstructive pulmonary disease (COPD) is a risk factor for development of severe pathological changes in the peripheral lungs of patients with COVID-19. However, the underlying molecular mechanisms remain unclear. Because bronchiolar club cells are crucial for maintaining small airway homeostasis, we sought to explore whether the altered susceptibility to SARS-CoV-2 infection of the club cells might have contributed to the severe COVID-19 pneumonia in COPD patients. Our investigation on the quantity and distribution patterns of angiotensin-converting enzyme 2 (ACE2) in airway epithelium via immunofluorescence staining revealed that the mean fluorescence intensity of the ACE2-positive epithelial cells was significantly higher in club cells than those in other epithelial cells (including ciliated cells, basal cells, goblet cells, neuroendocrine cells, and alveolar type 2 cells). Compared with nonsmokers, the median percentage of club cells in bronchiolar epithelium and ACE2-positive club cells was significantly higher in COPD patients. In vitro, SARS-CoV-2 infection (at a multiplicity of infection of 1.0) of primary small airway epithelial cells, cultured on air-liquid interface, confirmed a higher percentage of infected ACE2-positive club cells in COPD patients than in nonsmokers. Our findings have indicated the role of club cells in modulating the pathogenesis of SARS-CoV-2-related severe pneumonia and the poor clinical outcomes, which may help physicians to formulate a novel therapeutic strategy for COVID-19 patients with coexisting COPD.

Clara cell 10-kD protein (CC10) is one of the most abundant proteins in the respiratory secretions, and plays an important role in immune response, anti-infection and lung injury repair. Chronic obstructive pulmonary disease and bronchial asthma are common chronic lower respiratory tract inflammatory diseases, the pathogenesis of which are intimately related to the abnormal expression of CC10. Therefore, an in-depth research of the biological characteristics of CC10 are helpful for exploring for the important targets for the treatment of chronic respiratory inflammatory diseases in the future. This review summarizes the current research progress in this field. DOI: 10.11855/j.issn.0577-7402.2020.02.08

Theoretical distributions of medium-volatile impurities in distillates of terbium(Tb) metal were discussed and analyzed, and theoretical distributions were verified by vacuum distillation purification experiments with the different distillation temperatures. The research results indicated that, Fe and Cu in Tb metal are medium-volatile impurities, the mass-transfer control steps of Fe and Cu impurities are the hybrid mass-transfer process, the effective separation coefficients of above impurities are in the range of 1～2, and distributions of above impurities in distillates present linearly decreasing tendency as the distillation proceeds; there are the similar distribution rules between the theoretically calculated results and experimental results, and the experimental results are less than the theoretically calculated results, which the average standard deviations of Fe impurity at 1790 °C, 1820 °C and 1850 °C are ±0.352, ±0.256 and ±0.284 respectively, and that of Cu impurity are ±0.327, ±0.356 and ±0.290 respectively; the experimental removal rates of Fe and Cu impurities are only in the range of 20～35%, indicating that the medium-volatile impurities of Fe and Cu in Tb metal can be hardly removed by vacuum distillation.

Single-layer latticed domes belong to structure of imperfection sensitivity. The randomly appears various initial geometric imperfection affected the ultimate load carrying capacity of the structure to some degree. To improve structural sensitivity, this paper proposed a new optimum design method considering the requirement of constant stability that is through section optimization design of reticulated domes to make those values of ultimate load carrying capacity shrinks toward equality that were obtained by section optimization and considering many different stochastic initial geometric imperfections. First we add stability constraint into the process of optimization design and the global stability analysis are considering. Then we group the members of structure according to sensitive rate of ultimate bearing capacity to imperfections and sequence two-stage algorithm is adopted to improve the section optimization design. Using single-layer K6 reticulated dome with span of 60 meters and rise of 15 meters as an example, the computed results show that, compared to the structure that has not been optimized in terms of section, those values of ultimate load carrying capacity of optimized structure considering 28 stochastic initial geometric imperfections, whose average value is bigger and the standard deviation is smaller. So we've got a section optimization result to make the structure’s ultimate load carrying capacity pretty robustness and less volatile. In other words, the sensibility of ultimate load carrying capacity to imperfection is decreased and the amount of steel is reduced.

According to the principle of harmonious dimensions, the qualitative distribution model of the internal pressure on elbow pipes were determined; Through FLUENT numerical simulation, the internal pressure were given under 96 kinds of gas fluid conditions; By analyzing the variation of the internal pressure with flow and geometrical parameters, the variation of the internal pressure distribution within the elbow pipes has been studied; By means of 1stOpt nonlinear fitting package, the formula of three-dimensional internal pressure distribution was determined; Compared with the numerical results, the maximum relative error is 0.012%. The formula provides theoretical bases for strength check, the transport pipeline and wall thickness design of the high pressure, high velocity elbow.

In order to study the vibration and seismic performance of K8 triangular cone partial double layer spherical reticulated shell and analyze the factors that impact its self-vibration and seismic performance, this paper used parametric design language APDL of ANSYS to establish the shell model,then used 3D El-Centro seismic waves to analyze the influencing factors of its self-vibration and seismic performance by changing the ratio of rise to span, the ratio of thickness to span, bar section area and other parameters. Therefore this paper get some conclusions with engineering significance.

In order to grasp how the sectional sizing optimum design imposes effect on the global stability of latticed shell, with an example of K6 single-layer reticulated shell whose span is 60 meters and vector height is 6 meters, the impact of different ways in rods grouping and valuing sectional size on bars buckling discipline and mechanical performance was analyzed. Factors like the strength and slenderness ratio of members, local and overall stability of structure are entirely taken into account to guarantee the accuracy of the analysis results. The results show that optimum design of sectional sizing on single-layer latticed shell can reduce the steel consumption, change the buckling discipline and improve the ultimate stable bearing capacity of structure, but simultaneously it would bring about a smaller deformation, and no significant early warning of damage comes up when structural instability failure occurs.

Hexagonal grid cylindrical latticed shell structure is proposed, due to honeycomb structure (although the hexagon structure) is the most effective structure on save the building materials. As a result of the shell structure always with numerous bars, the distribution of internal force and the design of bars often rely on many parameters, likes the span of the structure, the rise-span ratio of the structure, the size of mesh etc., the large scaled finite element software ANSYS parametric design language ANSYS Parametric Design Language (APDL) be used to establish the model of hexagonal grid single-layer cylindrical reticulated shell. The optimization design also was done to found whether the model was a feasibility one. The analysis process shows that the parametric design method provides great convenience for the design of the structure.

According to the rules of six typical spherical reticulated shell nodes, the modeling method and the design macro program is developed for the nodes and the bars of six typical semi-outdoor spherical reticulated shell structures by using the ANSYS parametric design language APDL, so as to achieve the parametric design of six typical semi-outdoor spherical reticulated shells. The modeling design examples indicate that it's convenient to achieve the parametric modeling and design of semi-outdoor shell with given span S, rise high F, number of hoop symmetry areas kn, radial node cycles of whole structure nx and the upper removed laps ns, which provides big convenience for the force analysis and the optimization scheme comparison of semi-outdoor spherical lattice shells with varied types and geometric parameters.

The five double layer cylinder reticulated shells (single diagonal rod cylinder reticulated shell, Foeppl cylinder reticulated shell, double diagonal rod cylinder reticulated shell, lamella cylinder reticulated shell and three way grid of cylinder reticulated shell) are developed by adopting the upper and lower translation method. Five connection forms of web member (cross truss, positive four pyramidal, upend four pyramidal, evacuated positive four pyramidal, evacuated upend four pyramidal) and the methods of the node generation and element connection are established in the cylindrical coordinate system. By using the ANSYS parametric design language APDL, the corresponding parametric design macro program is developed so that the five double-layer cylindrical shells can be parametrically modeled under the given parameters such as shell type, shell span D, rise high t, thickness h, length L and number of grids m and n, etc. Examples prove that this method is simple, efficient and pragmatic, which provides great convenience for the force analysis and the optimization scheme comparison.

Based on the structure features of double primary ribs reticulated domes, a method for node generation and element connection of six typical double primary ribs reticulated domes was produced in spherical coordinate system. A macro program was designed by using ANSYS Parametric Design Language (APDL). This six typical double primary ribs reticulated dome modeling was realized under given parameters such as span, rise high, double primary ribs thickness, grid number in circular and radial direction. It is proved by several examples that this method is simple, efficient and possible. It can be easily used to analyze the internal force and optimized design in shell structures.

l -DOPA (3,4-dihydroxyphenylalanine) production by Stizolobium hassjoo cells was investigated. After inducing an authentic callus, a potent cell line named Sh-2 was bred. The cell line was acclimated by repeated subcultures. The favorable conditions for obtaining high productivity of l -DOPA were found to be the precise control of pH, adequate IAA (indole-3-acetic acid) concentration and color of cells which reflect melanin production. By referring to the assumption that the prosthetic group of the phenol oxidase is copper and that the catalytic activity of the enzyme is based on the change of the valency of cupric ions, Cu ++ concentration in culture medium was increased. When Cu ++ concentration in basal Murashige-Skoog (MS) medium was increased 25-fold (0.625 mg/ l of CuSO 4 ·5H 2 O), the total l -DOPA content in the culture medium was about twofold that obtained in basal MS medium. A similar effect was confirmed with Co ++ . Another strategy used in this work was to lower the ionic strength in the culture medium so that inhibition of the cell growth can be reduced. Dilution of the MS medium influenced the l -DOPA content in the cells. A 1 3 dilution of MS medium supplemented with optimized concentrations of constituents determined from this investigation resulted in the 2.05-fold increase in l -DOPA content.