In many research works, the fluid medium in electroosmosis is considered to be a Newtonian fluid, while the polymer solutions and biological fluids used in biomedical fields mostly belong to the non-Newtonian category. Based on the finite volume method (FVM), the electroosmotic flow (EOF) of viscoelastic fluids in near-neutral (pH = 7.5) solution considering four ions (K+, Cl−, H+, OH−) is numerically studied, as well as the viscoelastic fluids’ flow characteristics in a microchannel described by the Linear Phan-Thien–Tanner (LPTT) constitutive model under different conditions, including the electrical double layer (EDL) thickness, the Weissenberg number (Wi), the viscosity ratio and the polymer extensibility parameters. When the EDL does not overlap, the velocity profiles for both Newtonian and viscoelastic fluids are plug-like and increase sharply near the charged wall. Compared with Newtonian fluid at Wi = 3, the viscoelastic fluid velocity increases by 5 times and 9 times, respectively, under the EDL conditions of kH = 15 and kH = 250, indicating the shear thinning behavior of LPTT fluid. Shear stress obviously depends on the viscosity ratio and different Wi number conditions. The EOF is also enhanced by the increase (decrease) in polymer extensibility parameters (viscosity ratio). When the extensibility parameters are large, the contribution to velocity is gradually weakened.
A retrospective study.To compare the accuracy of pedicle screw placement and proximal facet joint violation (FJV) in single-level degenerative lumbar diseases using cortical bone trajectory (CBT) and traditional trajectory (TT) techniques, and analyze their possible risk factors.CBT screws have been utilized increasingly to improve cortical bone contact to prevent screw pullout and reduce approach-related morbidity. However, the studies on intra-pedicular accuracy and proximal FJV between the two methods are rare.A total of 40 patients who required single-level instruments were included in the retrospective study treated with the CBT-TLIF and the TT-TLIF at a 1:1 ratio from March 2019 to August 2020. The radiographic outcomes were the intra-pedicular accuracy and proximal FJV. Moreover, the possible risk factors were assessed using bivariate and multivariate analyses.As for the intra-pedicular accuracy, 73 screws (91.3%) were classified as grade A, 7 screws (8.7%) classified as grade B in the CBT group. A total of 71 screws (88.8%) were graded A with remaining 8 screws (10.0%) graded B and 1 screw (1.2%) graded C in the TT group. The proportion of optimal and clinically acceptable screw positions in the two groups were not significantly different (P > 0.05). In addition, the rate of proximal FJV in CBT approach (8.3%) was significantly lower than that in the TT approach (35.0%) (P < 0.001). Multivariate analysis showed the TT insertion approach and facet angle ≥45° were the independent risk factors for proximal FJV, but no factors above affected intra-pedicular accuracy.Compared with the TT approach in TLIF, the CBT approach showed similar intra-pedicular accuracy and remarkable superiority in proximal facet joint protection. Facet angle ≥45° is the independent risk factors for proximal FJV.Level of Evidence: 2.
A theoretical analysis of alkali metal thermal to electric converter is made in this paper. The dependence of output voltage, maximum electric power density of electrode and efficiency of electrode on working temperature, electric current density of electrode and surface resistance of BASE are deduced.
The problem of water shortage needs to be solved urgently. The membrane-embedded microchannel structure based on the ion concentration polarization (ICP) desalination effect is a potential portable desalination device with low energy consumption and high efficiency. The electroosmotic flow in the microchannel of the cation exchange membrane and the desalination effect of the system are numerically analyzed. The results show that when the horizontal electric field intensity is 2 kV/m and the transmembrane voltage is 400 mV, the desalting efficiency reaches 97.3%. When the electric field strength increases to 20 kV/m, the desalination efficiency is reduced by 2%. In terms of fluid motion, under the action of the transmembrane voltage, two reverse eddy currents are formed on the surface of the membrane due to the opposite electric field and pressure difference on both sides of the membrane, forming a pumping effect. The electromotive force in the channel exhibits significant pressure-flow characteristics with a slip boundary at a speed approximately six times that of a non-membrane microchannel.
Metformin is an antidiabetic agent that is used as the first-line treatment of type 2 diabetes mellitus. Gallic acid is a type of phenolic acid that has been shown to be a potential drug candidate to treat diabetic kidney disease, an important complication of diabetes. We aimed to test whether a combination of gallic acid and metformin can exert synergetic effect on diabetic kidney disease in diabetic mice model.Streptozotocin (65 mg/kg) intraperitoneal injection was used to induce diabetic kidney disease in mice. The diabetic mice were treated with saline (Vehicle), gallic acid (GA) (30 mg/kg), metformin (MET) (200 mg/kg), or the combination of gallic acid (30 mg/kg) and metformin (200 mg/kg) (GA + MET).Our results demonstrated that compared to the untreated diabetic mice, all three strategies (GA, MET, and GA + MET) exhibited various effects on improving renal morphology and functions, reducing oxidative stress in kidney tissues, and restoring AMP-activated protein kinase (AMPK)/silent mating type information regulation 2 homolog 1 (SIRT1) signaling in kidney tissues of diabetic mice. Notably, the combination strategy (GA + MET) provided the most potent renal protection effects than any single strategies (GA or MET).Our results support the hypothesis that gallic acid might serve as a potential supplement to metformin to enhance the therapeutical effect of metformin.
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