Improvement of Newman inequality

AbstractLet a=exp(−1/n). Newman inequality is∏k=1n−11−ak1+ak<e−n,∀n⩾5. We prove in this paper that∏k=1s−11−ak1+ak=n14e−π24n+O(1),∀s⩾n, which will be applied to improve the estimate concerning the approximation of |x| by using Newman's construction

Preliminary study of improving immune tolerance in vivo of bioprosthetic heart valves through a novel antigenic removal method

The durability of bioprosthetic heart valves is always compromised by the inherent antigenicity of biomaterials. Decellularization has been a promising approach to reducing the immunogenicity of biological valves. However, current methods are insufficient in eliminating all immunogenicity from the biomaterials, necessitating the exploration of novel techniques. In this study, we investigated using a novel detergent, fatty alcohol polyoxyethylene ether sodium sulfate (AES), to remove antigens from bovine pericardium. Our results demonstrated that AES treatment achieved a higher pericardial antigen removal rate than traditional detergent treatments while preserving the mechanical properties and biocompatibility of the biomaterials. Moreover, we observed excellent immune tolerance in the in vivo rat model. Overall, our findings suggest that AES treatment is a promising method for preparing biological valves with ideal clinical application prospects

Acceleration of two-grid stabilized mixed finite element method for the Stokes eigenvalue problem

summary:This paper provides an accelerated two-grid stabilized mixed finite element scheme for the Stokes eigenvalue problem based on the pressure projection. With the scheme, the solution of the Stokes eigenvalue problem on a fine grid is reduced to the solution of the Stokes eigenvalue problem on a much coarser grid and the solution of a linear algebraic system on the fine grid. By solving a slightly different linear problem on the fine grid, the new algorithm significantly improves the theoretical error estimate which allows a much coarser mesh to achieve the same asymptotic convergence rate. Finally, numerical experiments are shown to verify the high efficiency and the theoretical results of the new method

Integrated analysis of autoimmune pancreatitis by CT, MRCP and DWI

Purpose: CT, MRCP and diffusion weighted imaging characteristics were discussed to improve the diagnostic accuracy of autoimmune pancreatitis. Materials and methods: 23 cases of confirmed autoimmune pancreatitis were retrospectively analyzed before treatments. 23 cases underwent CT unenhanced and enhanced scans, 21 cases underwent MRCP examination, and 11 cases underwent DWI examination. Pancreatic lesion, involvement of the pancreatic duct and bile duct, changes of adjacent artery and vein, and other organs lesions. CT values and ADC values of pancreas and lesion were measured. Results: Focal type lesions were shown in 6 cases, diffuse type in14 cases, and both types in 3 cases. Diffuse pancreatic swelling was shown in 20 cases, and peripancreatic halo in 13 cases. Mean CT values of lesions: unenhanced scan 35.81 ± 6.23 HU, late arterial phase 75.80 ± 17.47 HU, venous phase 93.19 ± 14.06 HU, and equilibrium phase 90.00 ± 14.67HU. Delayed homogenous enhancement was shown in 17 cases. Tapered narrowing (12 cases) or multiple segmental pancreatic duct stenosis (8 cases) was detected, the absence of main pancreatic duct dilatation or less than 3.5 mm in 20 cases, and duct penetrating sign in 20 cases. Bile duct lesions were found in 20 cases. ADC values of lesions (0.99 ± 0.03 × 103 mm2/s) were significantly lower that of pancreas (1.47 ± 0.16 × 103 mm2/s). Conclusion: CT and MRI integrated diagnosis was helpful for accurate diagnosis based on the distinctive imaging characteristics of autoimmune pancreatitis

Experimental Study on Oxygen-Enriched Sintering of Vanadium-Titanium Magnetite

The influences of various factors, such as oxygen enrichment time, oxygen enrichment load, and ignition temperature, on the technical indices and sintering performance in the vanadium-titanium magnetite sintering process are simulated using sinter pot experiments. The experiments are based on the field production parameters of a sintering trolley in a steel enterprise in southwest China. Prolonged oxygen enrichment time results in the gradual increase in vertical sintering speed, sintering utilization coefficient, sintered ore yield, sintered ore drum strength, and reductivity. However, the low-temperature reduction pulverability of the sintered ore deteriorates. Oxygen enrichment load increases from 0 m3/h to 2.9 m3/h, and yield increases by 1.1%, while the vertical sintering speed and utilization coefficient increase slightly. Sintered ore drum strength increases from 65.33% to 68.00%, antiwear index decreases to 0.47%, and low-temperature reduction pulverability decreases from 65.07% to 62.85%. The increased ignition temperature is beneficial to improve the drum strength and yield of the ore but reduces the vertical sintering speed and utilization coefficient. With the increase in ignition temperature, the low-temperature reduction pulverability tends to increase first and then decrease. Changes in oxygen time, oxygen enrichment load, and ignition temperature have no significant effects on the soft melting performance of the sintered ore

Flexural Behavior of GFRP Tubes Filled with Magnetically Driven Concrete

Experimental investigation of GFRP (glass fiber reinforced polymer) tubes that were filled with magnetically driven concrete was carried out to study the flexural behavior of specimens under bending. Specimens having different cross section and lengths were tested. The test specimens were fabricated by filling magnetically driven concrete into the GFRP tubes and the concrete was vibrated using magnetic force. Specimens vibrated using vibrating tube were also tested for comparison. In addition, specimens having steel reinforcing bars and GFRP bars were both tested to study the effect of reinforcing bars on the magnetically driven concrete. The load-displacement curves, load-strain curves, failure mode, and ultimate strengths of test specimens were obtained. Design methods for the flexural stiffness of test specimens were also discussed in this study

Behavior of Cross Arms Inserted in Concrete-Filled Circular GFRP Tubular Columns

Fiber-reinforced polymer (FRP) materials nowadays have attracted much attention in both retrofitting of aged infrastructure and developing of new structural systems attributed to the outstanding mechanical properties. Extensive studies have been performed on concrete-filled glass FRP (GFRP) tubes for the potential application in piling, poles, highways overhead sign structures and bridge components. The new hybrid member also provides an alternative solution for traditional transmission structures. However, the connection between concrete-filled GFRP tubes and cross arms has not been fully understood. In this paper, an experimental study and theoretical analysis were conducted on the behavior of cross arms inserted in concrete-filled circular GFRP tubular columns. Steel bars with a larger stiffness in comparison with GFRP tubes were selected here for the cross arm to simulate a more severe scenario. The structural responses of the system when the cross arms were subjected to concentrated loads were carefully recorded. Experimental results showed that the concrete-filled GFRP tubes could offer a sufficient restraint to the deformation of the cross arm. No visible cracks were found on the GFRP tube at the corner of the cross arm where the stress and strain concentrated. Theoretical solutions based on available theories and equations were adopted to predict the displacement of the cross arms and a good agreement was achieved between the prediction results and experimental findings