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Abstract Bear bile, a valuable animal-derived medicinal substance primarily composed of tauroursodeoxycholic acid (TUDCA), is widely distributed in the medicinal market across various countries due to its significant therapeutic potential. Given the extreme cruelty involved in bear bile extraction, researchers are focusing on developing synthetic bear bile powder as a more humane alternative. This review presents an industrially practical and environmentally friendly process for producing an artificial substitute for bear bile powder using inexpensive and readily available chicken bile powder through an immobilized 7α-,7β-HSDH dual-enzymatic syste. Current technology has facilitated the industrial production of TUDCA from Tauodeoxycholic acid (TCDCA) using chicken bile powder. The review begins by examining the chemical composition, structure, and properties of bear bile, followed by an outline of the pharmacological mechanisms and manufacturing methods of TUDCA, covering chemical synthesis and biotransformation methods, and a discussion on their respective advantages and disadvantages. Finally, the process of converting chicken bile powder into bear bile powder using an immobilized 7α-Hydroxysteroid Dehydrogenases(7α-HSDH) with 7β- Hydroxysteroid Dehydrogenases (7β-HSDH) dual-enzyme system is thoroughly explained. The main objective of this review is to propose a comprehensive strategy for the complete synthesis of artificial bear bile from chicken bile within a controlled laboratory setting. Graphical Abstract

As the lightest metal structural materials, magnesium (Mg) alloys offer extensive application potential. Gadolinium (Gd), as the primary alloying element in Mg alloys and recognized for its notable thermal neutron capture cross-section, is considered one of the most efficient neutron absorbers. Thus, the Mg–Gd alloy is highly expected to emerge as a material with remarkable neutron absorption capacity. Hence, in this study, the thermal neutron-shielding capabilities of Mg–Gd alloys were comprehensively examined by fabricating four as-cast Mg–xGd alloys with varying compositions (x = 0, 5, 10, and 15 wt%). The obtained results were further corroborated by sophisticated modeling and calculations using SuperMC. The results revealed a direct correlation between the thermal neutron absorption capacity of the Mg–Gd alloys and the increase in Gd content, with a noteworthy neutron attenuation factor of 22.33. Moreover, in an Au ion irradiation experiment conducted at 200°C, the Mg–15Gd alloy exhibited exceptional radiation resistance, with a displacement per atom (dpa) of 10. The matrix and second-phase regions were devoid of any cavity formation. Instead, a finite number of dislocation rings were observed, forming both leaf-like and granular Gd-rich nanoscale precipitates. This study underscores the versatility of Mg–Gd alloys as efficient neutron shielding materials and structural materials tailored for applications demanding radiation resistance in diverse environments.

Background and aim: Spontaneous rupture of hepatocellular carcinoma (HCC) is a life-threatening complication, and patients who experience it are formally assigned to stage T4 in the TNM system, while many clinicians informally assign them to stage C in the more widely used Barcelona Clinic Liver Cancer (BCLC) system. The present study explored whether these re-staging practices are appropriate for HCC patients who suffer tumor rupture. Methods: We retrospectively reviewed the records of 1952 HCC patients who underwent hepatic resection at our hospital between January 2017 and June 2021. We compared recurrence-free and overall survival between 143 patients who had BCLC stage A or B disease at the time of spontaneous rupture and 449 patients who had BCLC stage C disease without rupture. Results: Overall survival rate was significantly higher among the 143 patients (1, 3, 5-year survival rate was 80.3%, 60.4%, 51.4%) with rupture than among the 449 (1, 3, 5-year survival rate was 69.5%, 41.5%, 32.4%) with BCLC stage C disease (hazard ratio 1.65, 95% confidence interval 1.29 to 2.12). The two groups had similar recurrence-free survival (hazard ratio 1.19, 95% confidence interval 0.92 to 1.53), but most patients with rupture were able to receive interventional and potentially curative treatments after recurrence, whereas most patients in BCLC stage C received interventional or supportive care. Similar results were obtained after propensity score matching. Conclusion: HCC patients who experience spontaneous rupture tumor while in BCLC stage A or B have better prognosis than patients in BCLC stage C without rupture. Our results suggest that HCC patients who suffer rupture in BCLC stage A or B should not be assigned to BCLC stage C.

Objective： To detect the level of parathion-methyl and parathion residues in different types of tea by high pressure liquid chromatography coupled with matrix solid phase dispersion. Methods： Before determined by high pressure liquid chromatography （HPLC）, the tea samples were pretreated by matrix solid phase dispersion method grinding with neutral alumina as dispersant and eluting by ethyl acetate: n-hexane （8%）. Results： The results showed that this method was simple, rapid and accurate, with good linearity （0.999 6 for parathion-methyl and 0.999 5 for parathion）, low detection limits （0.015, 0.006 mg/kg, respectively） and high recoveries （90.67% and 86.67%, respectively）. Incidence of parathion-methyl and parathion occurred with a frequency of 7.69% and 19.23%, and the average concentration of 0.004 8 mg/kg and 0.008 5 mg/kg, respectively. The residue levels varied from tea types. The corresponding average daily intake of parathion-methyl and parathion by drinking was 0.023 6 and 0.104 1 μg/（kg·d·BW）, respectively. Conclusion： The problem of methyl parathion and parathion residues in different tea samples was not prominent, and their residues did not exceed the standard. The detection probability and residue of parathion were higher than those of methyl parathion. The probability of parathion detection in oolong tea, black tea and green tea was higher, but the analysis data showed that there was no health risk problem caused by drinking tea for general consumers.

Low ionic conductivity in gel polymer electrolytes (GPEs) affects low dye-sensitized solar cells (DSSCs) performance is a crucial issue. Generally, the GPEs contain polymer (act as solvent holder), solvent, and salt (as ions provider). Usually, the GPE-based DSSCs are assembly with three necessary compartments: working electrode, GPE, and platinum electrode. The DSSCs parameters are included open-circuit voltage, Voc; short-circuit current density, Jsc; fill factor, ff and efficiency, %. This review's main objective was to explore an additive such as plasticizer, filler, and ionic liquid effects on the ionic conductivity in GPEs by improving ions mobility and expanding the free volume of the GPE. The impact of additives in the GPE is also expected to enhance the DSSCs performance by increasing the Jsc, Voc, ff, and efficiency. This comprehensive review discussed the latest progress of GPE utilizing the additive by listing the literature from the recent ten years.

Objective To observe the effect of bilirubin (Bil) on sorafenib (Sor) in the treatment of liver cancer and explore the involved molecular mechanisms. Methods In vitro, Huh7 cells were treated with different concentration of Sor (0, 2, 4, 8, 16, 32 μmol/L), of Bil (0, 2.5, 5, 10, 20, 40 μmol/L) and of Sor (0, 2, 4, 8, 16, 32 μmol/L) +Bil (20 μmol/L) for 24, 48 and 72 h. Cell viability was detected by CCK-8 assay. Huh7 cells were treated with Sor (4 μmol/L), Bil (20 μmol/L) and Sor (4 μmol/L)+Bil (20 μmol/L), cell cycle was detected by flow cytometry after 48 h, and the effects of drugs on cell proliferation were detected by clone formation assay after 14 d. In vivo, 16 mice bearing xenografts of Huh7 cells were divided into Con group, Bil group (25 mg·kg-1·d-1), Sor group (15 mg·kg-1·d-1) and Bil(25 mg·kg-1·d-1)+Sor(15 mg·kg-1·d-1) group (n=4), according to the S type sampling method. The expression levels of peroxisome proliferator-activated receptor (PPARα) and carnitine palmityl transferase 1A (CPT1A) were detected by Western blotting and real time PCR. After etomoxir (Eto), the inhibitor of CPT1A, was added, CCK-8 and clone formation assay were used to verify the mechanisms correlated with PPARα/CPT1A. Results CCK-8 results showed that the inhibitory effect of Sor on Huh7 cells was in a dose and time-dependent manner (P < 0.05), and Bil had no significant effect on Huh7 cells (P>0.05). Compared with Sor group, the cell proliferation in Bil+Sor group was increased (P < 0.05), the relative cell colony formation rate was grown (P < 0.05), and the number of cells in S phase was decreased (P < 0.05). In vivo, results showed that the tumor volume and weight of Sor group were lower than that of Con group (P < 0.05), and the tumor volume and weight of Bil+Sor group were higher than those of Sor group (P < 0.05). Western blotting and RT-qPCR results showed that PPARα and CPT1A expression levels were increased in Bil+Sor group compared with Sor group (P < 0.05). After Eto was added, the cell proliferation and the relative cell clone formation rate of Bil+Sor+Eto group were decreased compared with Bil+Sor group (P < 0.05). Conclusion Bil impairs the antitumor effects of sorafenib treatment in hepatocellular carcinoma through fatty oxidation by up-regulating PPARα/CPT1A.

Magnesium-based composites are promising materials that can achieve higher strength, modulus, stiffness, and wear resistance by using metals, ceramics, and nanoscale carbon-based materials as reinforcements. In the last few decades, high-performance magnesium-based composites with excellent interfacial bonding and uniformly distributed reinforcements have been successfully synthesized using different techniques. The yield strength, Young’s modulus, and elongation of SiC nanoparticle-reinforced Mg composites reached ∼710 MPa, ∼86 GPa, and ∼50%, respectively, which are the highest reported values for Mg-based composites. The present work summarizes the commonly used reinforcements of magnesium composites, particularly nano-reinforcements. The fabrication processes, mechanical properties, reinforcement dispersion, strengthening mechanisms, and interface optimization of these composites are introduced, and the factors affecting these properties are explained. Finally, the scope of future research in this field is discussed.

Cardiovascular diseases are among the major health problems that are likely to benefit from promising developments in quantum machine learning for medical imaging. The chest X-ray (CXR), a widely used modality, can reveal cardiomegaly, even when performed primarily for a non-cardiological indication. Based on pre-trained DenseNet-121, we designed hybrid classical–quantum (CQ) transfer learning models to detect cardiomegaly in CXRs. Using Qiskit and PennyLane, we integrated a parameterized quantum circuit into a classic network implemented in PyTorch. We mined the CheXpert public repository to create a balanced dataset with 2436 posteroanterior CXRs from different patients distributed between cardiomegaly and the control. Using k-fold cross-validation, the CQ models were trained using a state vector simulator. The normalized global effective dimension allowed us to compare the trainability in the CQ models run on Qiskit. For prediction, ROC AUC scores up to 0.93 and accuracies up to 0.87 were achieved for several CQ models, rivaling the classical–classical (CC) model used as a reference. A trustworthy Grad-CAM++ heatmap with a hot zone covering the heart was visualized more often with the QC option than that with the CC option (94% vs. 61%, p < 0.001), which may boost the rate of acceptance by health professionals.

In order to provide wheat quality information for wheat purchasing & storage companies and processing companies in Hebei Province and provide technical basis for the rational use of local wheat resources,The newly harvested wheat from the main wheat producing areas in Hebei Province from 2010 to 2019 was tested for quality indicators such as test weight,mass of 1000 grains,unsound kernel content,sprouted kernel content,moisture content,hardness index,falling number,wet gluten content,and protein content.The quality of wheat in Hebei Province in the past ten years was analyzed from three aspects:the annual change of each detection index,the comparison of the average value of the detection index of each city,and the comparison of the selection of the detection index of each city.The results showed that the quality of wheat was normal except for 2013 and 2018.The quality of wheat in 2013 was the worst in ten years.The test weight,mass of 1000 grains and falling number of wheat were all at the lowest values.The unsound kernel content and sprouted kernel content and moisture content were at the highest values.In the data of past ten years,the wheat in Xinji City has obvious comparative advantages in terms of high test weight,high mass of 1000 grains weight,low unsound kernel content,and high wheat hardness index.In addition,wheat from Handan,Xingtai and Shijiazhuang City has obvious comparative advantages in terms of high test weight.

This study aims to evaluate the effect of protocatechuic acid (PCA) on human hair follicle melanocytes (HFM). Normal primary HFM were isolated and cultured till logarithmic period of second passage, then treated with different concentrations of PCA (0.1–200 μmol L−1) to study the cell proliferation, melanin contents, tyrosinase activity and protein and mRNA expression of melanogenic genes (tyrosinase-related protein 1 (TRP-1), tyrosinase-related protein 2 (TRP-2), and microphthalmia-associated transcription factor (MITF)) in the cultured HFM. In addition, we have also measured the contents of superoxide dismutase (SOD) and glutathione (GSH) in PCA treated HFM. Vitamin C was used as a positive control. The result showed that PCA can decrease the synthesis of melanin and the tyrosinase activity with IC50 = 8.9 μmol L−1 and IC50 = 6.4 μmol L−1, respectively, at the treatment time of 24 hours, without inducing any cytotoxicity in HFM cells. In addition, the mRNA transcription and protein expression levels of TRP-1, TRP-2 and MITF significantly decreased with a dose-dependent manner after 24-hour PCA treated in HFM cells. Furthermore, PCA has significantly increased the SOD and GSH activity in a dose-dependent manner for 24-hour PCA treatment. This study suggested that PCA has an inhibitory effect on the production of melanin through down-regulation of the expression of melanogenesis-related protein and the effect of anti-oxidation, which could be useful for the therapy of melanin overproduction or skin whitening.

Persistent tapetal cell1 (PTC1) plays a curial role in pollen development, and is thought to function as a transcriptional activator in rice. However, the molecular mechanism of PTC1 in regulating pollen development and its cis-elements are not well understood. We identified a novel weak male sterility mutant (ms92) which exhibited expanded tapetum and shrink pollen grains. Map-based cloning and allelic analysis suggested that the male sterility of ms92 was caused by a DNA fragment substitution in the promoter of PTC1. The decreased expression of MS92/PTC1 in ms92 and cis-element analysis indicated that the substituted sequence contained several potential binding cis-element of negative feedback. MS92/PTC1 was specifically expressed in tapetum and microspores at the young microspore stage, and its protein was localized in nucleus. We further found that MS92/PTC1 functions as a transcription activator by recognizing H3K4me3. Transcriptomic analysis revealed that a number of genes involved in tapetum degeneration and pollen wall formation were down-regulated in ms92, which are the potential targets of MS92/PTC1. The substitution fragment in MS92/PTC1 promoter was essential for pollen development, and we provided a novel mutant for further identifying the cis-elements in promoter and the molecular network of MS92/PTC1.

The surface treatment was carried out on the surface of materials of A473M martensitic stainless steel axle sleeve by rolling technology, aiming to investigate the effect on its mechanical properties. The surface morphology and roughness, residual stress, microhardness, tensile and fatigue property were systematically studied using the SEM, white light interferometer, X-ray diffractometer, microhardness tester, EBSD, tensile tester and fatigue tester. The results show that the surface roughness of rolling specimen reduces significantly, which is about 1/5 of that of turning surface. The residual compression stress is induced near surface by rolling processing, the maximum value can reach up to 946 MPa and the residual compression stress decreases along with the depth. The thickness of the residual compression stress layer is about 200 μm. In addition, the rolling surface microhardness can be improved by 30% compared with that of turning surface and the hardened layer can be about 200 μm. As for mechanical properties, the tensile strength, yield strength and elongation of rolling specimens increase about 40%, 22% and 8% respectively compared with that of turning specimens. The fatigue life increases from 5.4×104 cycles to 1×107 cycles after rolling processing. The mechanical properties of the rolled material significantly improve, and the fatigue life significantly increases.

In the post-Three Gorges period,the deep evolution of the relationship between the Yangtze River and Dongting Lake breaks the hydraulic pattern that the water flows into Datong Lake from the northwestern corner and discharges from the southeastern corner of Datong Lake.To study the ecological water replenishment cycle and the characteristics of flow field distribution of Datong Lake under variant environment,we build a two-dimensional hydrodynamic model of water systems based on MIKE 21FM and simulate the hydrodynamic conditions for the project of river-lake connection and ecological water replenishment of Datong Lake.Then,the water replenishment cycle and flow field morphological characteristics of Datong Lake are studied under six scenarios,such as different ecological water replenishment flow and different gate control,and the critical point of ecological water replenishment efficiency is presented.The results reveal that the flow rate distribution of the control scheme of “single in-double out” is more uniform than that of the control scheme of “single in-single out.” During the non-irrigation period,when the flow of ecological water replenishment is 20.48 m3/s,and the pump flow of the Mingshan Station is 10.5 m3/s,the percentage of the lake area with a flow rate of 0.5~5.0 mm/s to the total area is about 79.96%,with a replenishment cycle of 95 d;during the irrigation period,when the flow of ecological water replenishment is 28.92 m3/s,and the pump flow of the Mingshan Station is 10.5 m3/s,the percentage of the lake area with a flow rate of 0.5~5.0 mm/s is about 87.82%,with a replenishment cycle of 80 d.

The surface treatment was carried out on the surface of materials of A473M martensitic stainless steel axle sleeve by rolling technology, aiming to investigate the effect on its mechanical properties. The surface morphology and roughness, residual stress, microhardness, tensile and fatigue property were systematically studied using the SEM, white light interferometer, X-ray diffractometer, microhardness tester, EBSD, tensile tester and fatigue tester. The results show that the surface roughness of rolling specimen reduces significantly, which is about 1/5 of that of turning surface. The residual compression stress is induced near surface by rolling processing, the maximum value can reach up to 946 MPa and the residual compression stress decreases along with the depth. The thickness of the residual compression stress layer is about 200 μm. In addition, the rolling surface microhardness can be improved by 30% compared with that of turning surface and the hardened layer can be about 200 μm. As for mechanical properties, the tensile strength, yield strength and elongation of rolling specimens increase about 40%, 22% and 8% respectively compared with that of turning specimens. The fatigue life increases from 5.4×104 cycles to 1×107 cycles after rolling processing. The mechanical properties of the rolled material significantly improve, and the fatigue life significantly increases.

Diabetic nephropathy (DN) is a major cause of mortality in patients with diabetes, but there is a lack of effective therapeutic drugs for the disease treatment. Betacyanins (BCN) derived from plants exhibits anti-oxidative, anti-tumor and anti-inflammatory activities. However, its effects on DN have not been reported. In this study, we found that BCN supplementation markedly alleviated metabolic disorder and renal dysfunction in db/db mice. Additionally, BCN treatment obviously mitigated podocyte damage in diabetic mice, as evidenced by the decreased glomerular basement membrane thickness and the foot process width. Pathological analysis demonstrated that renal fibrosis was significantly inhibited by BCN through suppressing transforming growth factor (TGF)-β1/SMADs signaling in diabetic mice. Furthermore, diabetes-induced oxidative stress in kidney samples was evidently reduced in mice supplemented with BCN by improving nuclear factor erythroid-derived 2-related factor 2 (Nrf2) nuclear expression. The anti-fibrotic and anti-oxidant activities of BCN were confirmed in high glucose (HG)-stimulated podocytes in vitro. Importantly, we found that Nrf2 suppression could further exacerbate HG-induced collagen accumulation and reactive oxygen species (ROS) production in podocytes. Meanwhile, BCN-ameliorated fibrosis and oxidative stress were almost abrogated by the Nrf2 knockdown in HG-incubated podocytes. These findings elucidated that BCN could alleviate DN through reducing collagen and ROS deposition mainly through improving the Nrf2 signaling, subsequently alleviating renal dysfunction. Thus, BCN could be considered as a promising therapeutic agent for DN treatment.

This paper proposes a novel grey wolf optimization-extreme learning machine model, namely, the GWO-ELM model, to train and predict the ground subsidence by combining the extreme learning machine with the grey wolf optimization algorithm. Taking an excavation project of a foundation pit of Kunming in China as an example, after analyzing the settlement monitoring data of cross sections JC55 and JC56, the representative monitoring sites JC55-2 and JC56-1 were selected as the training monitoring samples of the GWO-ELM model. And three kinds of GWO-ELM models such as considering the influence of time series, influence of settlement factors, and after optimization were established to predict the ground settlement near the foundation pit. The predictive results are that their average relative error and average absolute error are ranked from large to small as GWO-ELM model based on time series, GWO-ELM model based on settlement factors, and optimized GWO-ELM model for the three kinds of GWO-ELM models at monitoring points JC55-2 and JC56-1. Accordingly, the optimized GWO-ELM model has the strongest predictive ability.

Excess fat-rich diet ingestion predisposes the liver to non-alcoholic fatty liver disease (NAFLD), but the mechanism is complicated. Fisetin (Fn) as a natural flavonoid with many bio-activities was determined in a number of diseases models. TACE (tumor necrosis factor-α-converting enzyme)-combined tumor necrosis factor-α (TACE/TNF-α) signaling played a significant role in inflammation-associated diseases. The study aimed to explore the protective mechanisms of Fn against high fat diet (HFD)-induced nonalcoholic steatohepatitis (NASH), with particular focus on TACE/TNF-α signaling. HFD-fed C57BL/6 mice were used as the metabolic syndrome model to explore the effects of Fn on NASH and to determine whether TACE/TNF-α activation was involved in the process. Indeed, HFD increases systemic metabolic disorder, promotes circulating levels of pro-inflammatory cytokines produce, aggravates development of hepatic inflammation, resulting in inflammation overload-associated excessive activation of TACE/TNF-α, ultimately induces hepatic lipid accumulation and NASH. Fisetin protected against HFD-induced liver inflammation and lipid accumulation by decreasing metabolic disorder and inflammation overload-related TACE/TNF-α activation, inhibiting over-expression of pro-inflammatory cytokines, negatively regulating HFD-triggered abnormal lipid metabolism-related genes expression, finally restricting lipid deposition and hepatic steatosis. Fisetin suppressed HFD-induced liver inflammation and lipid accumulation by decreasing metabolic disorder and hepatic inflammation overload-related TACE/TNF-α activation.

Particulate matter (PM2.5) is a risk factor for organ injury and disease progression, such as lung, brain and liver. However, its effects on renal injury and the underlying molecular mechanism have not been understood. The inactive rhomboid protein 2 (iRhom2), also known as rhomboid family member 2 (Rhbdf2), is a necessary modulator for shedding of tumor necrosis factor-α (TNF-α) in immune cells, and has been explored in the pathogenesis of chronic renal diseases. In the present study, we found that compared to the wild type (iRhom2+/+) mice, iRhom2 knockout (iRhom2-/-) protected PM2.5-exposed mice from developing severe renal injury, accompanied with improved renal pathological changes and functions. iRhom2-/- mice exhibited reduced inflammatory response, as evidenced by the reduction of interleukin 1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α) and IL-18 in kidney samples, which might be, at least partly, through inactivating TNF-α converting enzyme/TNF-α receptors (TACE/TNFRs) and inhibitor of α/nuclear factor κ B (IκBα/NF-κB) signaling pathways. In addition, oxidative stress was also restrained by iRhom2-/- in kidney of PM2.5-exposed mice by enhancing heme oxygenase/nuclear factor erythroid 2-related factor 2 (HO-1/Nrf-2) expressions, and reducing phosphorylated c-Jun N-terminal kinase (JNK). In vitro, blockage of HO-1 or Nrf-2 rescued the inflammatory response and oxidative stress that were reduced by iRhom2 knockdown in PM2.5-incubated RAW264.7 cells. Similar results were observed in JNK activator-treated cells. Taken together, our findings indicated that iRhom2 played an essential role in regulating PM2.5-induced chronic renal damage, thus revealing a potential target for preventing chronic kidney diseases development. Keywords: PM2.5, Renal injury, iRhom2, Inflammation, Oxidative stress, JNK

The microstructure of alloy Mg-3Si(mass fraction/%, same as below) after successive additions with different elements of Zn, Nd, Gd and Y was observed and the microstructure evolution was investigated by scanning electron microscopy and X-ray diffraction. The results show the primary Mg2Si particles co-exist with eutectic Mg2Si particles in binary alloy Mg-Si. With minor addition of Zn element, only primary Mg2Si can be found in ternary Mg-3Si-3Zn system while eutectic Mg2Si particles disappear. In quaternary alloy Mg-2.0Nd-3.0Zn-3.0Si, the addition of Nd element can effectively refine the primary Mg2Si particles and form some Mg41Nd5 particles. After continuous adding of Gd and Y elements into quaternary system, Gd5Si3 and YSi particles increase significantly in the alloy Mg-8.0Gd-4.0Y-2.0Nd-3.0Zn-3.0Si, while volume fraction of primary Mg2Si decrease significantly. Thermo-Calc calculation predicts that the Gibbs free energy for primary particles Gd5Si3, YSi is lower, and therefore Gd, Y atom and Si are more likely to form compounds. In Mg-8Gd-4Y-2Nd-3Zn-3Si alloy, room temperature Gibbs free energy for primary particles Mg2Si, Gd5Si3, YSi is -9.56×104, -8.72×104, -2.83×104J/mol, respectively, and the mass fraction of these particles is 8.07%, 5.27%, 1.40% respectively.

To solving the problem that it is difficult to build an accurate solid model of meshing helical gears in ANSYS,a new parameterized approach to building an accurate solid model of meshing helical gear based on APDL is presented. The solid model of helical gear pair is built at the reference position based on the equations of the tooth profile curve equation. Taking the meshing position that helical gear pair has the minimum total length of contact lines as the initial meshing position,the rotational phase from the reference position to the initial meshing position of helical gear pair is determined,the initial solid model of meshing helical gears is built by rotating the helical gear pair based on the rotational phase. The equation of phase change in one contact lines distribution change cycle of meshing helical gears is established,then,the every meshing position of meshing helical gears in one contact lines distribution change cycle can be caught by the control of the meshing phase factor in the equation. The results of numerical experiment show that the meshing solid model of helical gear generated by the presented method has a good geometric precision,which can guarantee that the simulation results is credible.