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Hydraulic fracturing (HF) is an important technique for enhancing the permeability of petroleum and gas reservoirs. To understand the coupling response mechanism of fluid pressure and in situ stress during the expansion of hydraulic fractures-based on the theory of the fluid flow of seepage porous media and damage mechanics-a poromechanical model of hydraulic fracture propagation is proposed and the finite element method (FEM) numerical weak coupling calculation method of hydraulic fracturing is realized. First, the effect of the coupling stress field is described by introducing the β value of the amount of pore volume that varies, resulting from internal pressure per unit of fluid internal, and the coupling calculation method of the pore pressure-effective stress-element damage-pore pressure expansion coefficient is formulated. Second, based on the concept of damage localization, a calculation method for the hydraulic fracture opening equation is proposed, and then the element damage-hydraulic fracture opening-permeability tensor-pore pressure field calculation cycle is established. The model indicates four stages of fracture propagation: I, fracture nucleation, II, kinetic propagation, III, steady propagation, and IV, propagation termination. Finally, as an example, a numerical simulation of three-dimension hydraulic fracturing is performed. In comparison to previous research, the morphology of the fracture zone and the fluid pressure contour of the horizontal section are approximately ellipses, which verify the feasibility of the weak coupling calculation method; the fracture parameters verify its accuracy, which include the length, width, and fluid pressure., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Moxidectin (MXD), an antiparasitic drug, is effective for a variety of external and internal parasites in companion and farm animals. This study aimed to calculate the withdrawal period by investigating the residue depletion of MXD in swine edible tissues after pouring at the dosage of 2.5 mg/kg B.W. The concentrations of MXD in swine edible tissues were determined by a modified preparation procedure based on HPLC-FLD. The method was validated giving LOD and LOQ of 0.5 μg/kg and 1 μg/kg respectively with measured recoveries ranging from 62.9%-89.2% at three different concentrations and a precision (RSD) of less or equal to 15.7%. The muscle, liver, kidney and fat tissues were collected at 0.5, 5, 10, 20, 25 d after administration. The results showed that fat was the target tissue with the highest concentration for MXD. The withdrawal period was 26 days for the MRL of 500 μg/kg in fat. The results provide fundamental information to ensure food safety and establishment of a rational medication regimen.

Objective: It has been found that asphyxia influences proliferation and differentiation of brain neural stem cells in newborn animal models, and that peripheral blood stem cells play an important role in repairing brain damage. But it has not been reported yet whether asphyxia influences peripheral blood stem cells differentiating into neural cells, and whether with the progress of the disease there is a change of peripheral blood stem cells differentiating into neural cells in newborns with hypoxic ischemic encephalopathy (HIE)., Methods: Fifty term HIE infants were enrolled in research from March, 2007 to March, 2010. There were 10 cases of the severe HIE patients with good improvement, the severe HIE patients with poor improvement, the moderate HIE patients, the mild HIE patients and the controls, respectively. The peripheral mononuclear cells collected within 24 hours and on 7th day after birth were cultured in vitro for 10 days to differentiate into neural cells. The induced nestin positive cells were identified with Immunohistochemistry and counted. Findings : Within 24 hours after birth, there were no difference of induced nestin positive cells among the severe HIE patients with good improvement (68.99±7.85), the severe HIE patients with poor improvement (71.43±6.88), the moderate HIE patients (73.34±6.46), the mild HIE patients (70.46±6.66) and the controls (71.13±7.19, F=0.51, P=0.7). In the severe HIE patients with obvious improvement, the induced nestin positive cells from 7th day peripheral blood mononuclear cells (94.50±15.57) increased markedly compared with that within 24 hours (68.99±7.85, t=4.66, P<0.001), and were higher than the induced nestin positive cells from 7(th) day peripheral blood mononuclear cells in the severe HIE patients with no obvious improvement (94.50±15.57 vs 69.48±5.32, t=4.62, P<0.001)., Conclusion: The ability of peripheral mononuclear cells differentiating into neural cells in term infants with good improvement suffering from severe HIE was enhanced, which may suggest possible relationship between the brain repair and the peripheral stem cells.

Background: Volumetric intravascular ultrasound (IVUS) analysis has contributed significantly to the assessment of coronary artery disease. The aim of this study is to validate the novel IVUS analysis software (NICORAS) compared to the previously validated software (EchoPlaque)., Methods: Selected from clinical cases, we used 30 IVUS images that utilized motorized pullback at 0.5 mm/sec. Judging from at least two vascular landmarks, identical coronary artery segments were selected and analyzed with two software systems (NICORAS and EchoPlaque). Lumen and external elastic membrane (EEM) borderlines were traced at every 0.5 mm interval. Plaque area was calculated as EEM minus lumen area. Then, volumetric IVUS data were calculated using interpolated frame data from which lumen, EEM, and plaque volume were computed., Results: The average analyzed coronary segment was 15.4 +/- 4.3 mm. There was excellent agreement between NICORAS and EchoPlaque for lumen volume (r = 0.999, p < 0.0001), EEM volume (r= 0.999, p < 0.0001), and plaque volume (r = 0.998, p < 0.0001)., Conclusion: The new volumetric IVUS analysis software provided IVUS data similar to previously examined software.