Objective:To explore the method of obtaining the key parameters of the average value articulator in healthy people based on mandibular movement trajectory data, with a view to providing a reference for the clinical application of the average value articulator.Methods:One hundred healthy volunteers (42 males and 58 females) with individual normal occlusion, aged 18-55 years old, who met the inclusion criteria were recruited from Beijing, and their mandibular movement trajectory data were collected. The left and right sagittal condylar inclination(SCI) and transversal condylar inclination(TCI) were obtained from the values of the articulator parameters which were generated in the mandibular movement analysis system.The SCI and TCI were grouped by gender and calculated separately for the two groups and the overall sample; the gender differences in the two parameters and the differences between the mean values of the two parameters and the average value articulator empirical values (35° for SCI and 15° for TCI) for the overall sample were compared.Results:The differences between SCI (35.8°±7.4°) and TCI [11.2° (11.3°)] in males and the corresponding parameters [35.6°±8.3° and 10.8° (9.5°), respectively] in females were not statistically significant ( t=0.10, P=0.922; Z=-0.60, P=0.552); the overall sample SCI (35.7°±7.9°) did not differ statistically from the average value articulator empirical value ( t=1.23, P=0.221), and the overall sample TCI [10.9° (10.3°)] was significantly smaller than the average value articulator empirical value ( W=5 825.00, P<0.001). Conclusions:The mandibular movement trajectory data of 100 adults with individual normal occlusion in this study shows that the gender factor does not affect the setting of the key parameters of the average value articulator, the SCI of the average value articulator empirical values is appropriate, and the TCI has the possibility of being on the large side. In the clinical use of the articulator to assist in the design of restorations, the parameter values should be rationally adjusted according to the actual situation of the patient′s dentition and mandibular movement.

Objective This study proposes a chairside digital design and manufacturing method for band and loop space maintainers and preliminarily validates its clinical feasibility.Methods Clinical cases of 10 children requiring space maintenance caused by premature loss of primary teeth were collected.Intraoral scan data of the affected children were also collected to establish digital models of the missing teeth.Using a pediatric band and loop space maintainer de-sign software developed by our research team,a rapid personalized design of band and loop structures was achieved,and a digital model of an integrated band and loop space maintainer was ultimately generated.A chairside space maintainer was manufactured through metal computer numerical control machining for the experimental group,whereas metal 3D printing in the dental laboratory was used for the control group.A model fitting assessment was conducted for the space maintainers of both groups,and senior pediatric dental experts were invited to evaluate the clinical feasibility of the space maintainers with regard to fit and stability using the visual analogue scale scoring system.Statistical analysis was also performed.Results The time spent in designing and manufacturing the 10 space maintainers of the experimental group was all less than 1 h.Statistical analysis of expert ratings showed that the experimental group outperformed the control group with regard to fit and stability.Both types of space maintainers met clinical requirements.Conclusion The chairside digital design and manufacturing method for pediatric band and loop space maintainers proposed in this study can achieve same-day fitting of space maintainers at the first appointment,demonstrating good clinical feasibility and significant potential for clinical application.

Based on the domestic and foreign research on the application of self-disclosure in gynecological cancer patients, the relevant concepts, main modes of self-disclosure, measuring tools, research status and influencing factors of self-disclosure in gynecological cancer patients are reviewed. In order to provide a reference for the research on self-disclosure of gynecological cancer population, and promote the development of self-disclosure.

Objective:To establish an intelligent registration algorithm under the framework of original-mirror alignment algorithm to construct three-dimensional (3D) facial midsagittal plane automatically. Dynamic Graph Registration Network (DGRNet) was established to realize the intelligent registration, in order to provide a reference for clinical digital design and analysis.Methods:Two hundred clinical patients without significant facial deformities were collected from October 2020 to October 2022 at Peking University School and Hospital of Stomatology. The DGRNet consists of constructing the feature vectors of key points in point original and mirror point clouds (X, Y), obtaining the correspondence of key points, and calculating the rotation and translation by singular value decomposition. Original and mirror point clouds were registrated and united. The principal component analysis (PCA) algorithm was used to obtain the DGRNet alignment midsagittal plane. The model was evaluated based on the coefficient of determination (R 2) index for the translation and rotation matrix of test set. The angle error was evaluated on the 3D facial midsagittal plane constructed by the DGRNet alignment midsagittal plane and the iterative closet point (ICP) alignment midsagittal plane for 50 cases of clinical facial data. Results:The average angle error of the DGRNet alignment midsagittal plane and ICP alignment midsagittal plane was 1.05°±0.56°, and the minimum angle error was only 0.13°. The successful detection rate was 78% (39/50) within 1.50° and 90% (45/50) within 2.00°.Conclusions:This study proposes a new solution for the construction of 3D facial midsagittal plane based on the DGRNet alignment method with intelligent registration, which can improve the efficiency and effectiveness of treatment to some extent.

Objective:To conduct radiation detection and dose assessment in selective internal radiotherapy with 90Y resin microspheres for the purpose of providing a reference for radiological protection. Methods:The dose rates from radiotherapy with 90Y resin microspheres were detected in the process of each operation at different distances from the body surface of patients the levels of dose to the persons concerned were compared with the relevant national regulations and standards. Results:The estimated dose rates were 1.12-454 μSv/h during 90Y resin microspheres dispensing and 2.06-58.2 μSv/h during surgical procedure. The dose rates at 0.5 h after surgery were 22.7-64.1 μSv/h at 5 cm and 0.82-2.55 μSv/h at 1 m from three patient′s body surface. Assuming treating 200 patients a year, the annual individual effective dose to the radiation workers was 0.12-1.03 mSv/year. The annual individual effective dose to the public, comforters and carers of patients was 0.02-0.24 mSv/year after release of a patient. Conclusions:During the treatment, nursing and release of patients, the radiation doses to workers, carers and the public are lower than the individual dose limit given in the GB18871-2002 basic standards for protection against ionizing radiation and for the safety of radiation sources and the management target value set by of the relevant medical institutions.

BACKGROUND: In our previous studies, zinc-calcium-phosphate (Zn-Ca-P) coating has been successful y prepared on the surface of AZ31 magnesium al oy, which improves the corrosion resistance of the al oy. OBJECTIVE: To analyze the hemocompatibility of Zn-Ca-P coated AZ31 magnesium al oy in vitro. METHODS: Zn-Ca-P coating was prepared on the surface of AZ31 magnesium al oy using chemical transformation. Afterwards, the characteristics of the Zn-Ca-P coating were investigated using scanning electron microscope, and X-ray diffraction analyzed its components. Besides, hemocompatibility in vitro was evaluated by platelet adhesion assay, dynamic clotting time test and hemolysis test. RESULTS AND CONCLUSION: Under scanning electron microscope, a flower-like coating was formed ont surface of the AZ31 magnesium al oy, with the main chemical component of insoluble phosphates Zn3(PO4)2?4H2O. And some round distortionless blood platelets adhered to the surface of AZ31 magnesium al oy, with no pseudopodia. In dynamic clotting time test, the long curve of Zn-Ca-P coating tended to descend indicating better anticoagulant activity. And the hemolysis rate was below 5%. In conclusion, Zn-Ca-P coating has good hemocompatibility in vitro.

OBJECTIVETo establish a method for determining cyanamide in workplace air by high-performance liquid chromatography (HPLC).

METHODSAir samples were collected from the workplace using the shock absorption tube containing water solution at a rate of 2.8∼3.0 ml/min for 60 min; dansyl chloride was used as a derivatization reagent to conduct pre-column derivatization, and the procedure was as follows: acetone solution (2.5 ml), mixed solution (1.0 ml) containing 0.016 mol/L Na2CO3 and 0.184 mol/L NaHCO3, and 10 mg/ml acetone solution of dansyl chloride (0.5 ml) were added into the samples, and reaction proceeded in a water bath (50 °C) for 1 h. HPLC was performed on an ODS C18 column (250 mm × 4.6 mm, 5 üm) with a mobile phase of acetonitrile-phosphate buffer (35:65) at a flow rate of 1.0 ml/min and a column temperature of 25°C; a fluorescence detector was used at an excitation wavelength of 360 nm and an emission wavelength of 495 nm.

RESULTSThe minimum detectable concentration of cyanamide was 0.05 üg/ml; a good linear relationship was noted when the concentration of cyanamide was 0.2∼100.0 üg/ml; the intraday relative standard deviation (RSD) was 0.28%∼1.18%, and the interday RSD was 0.22∼2.16%; the recovery rate was 95.7%∼103.0%, and the sampling efficiency was 95.8%∼96.9%. Water solution of cyanamide (pH<6.5) could be stable in the dark at room temperature for 7 d.

CONCLUSIONThis method is stable, reliable, easy to operate, and highly sensitive and suitable for determination of cyanamide in workplace air.

OBJECTIVE To investigate the effects of lead exposure on the permeability,secretion and transportation function of blood-cerebro-spinal fluid barrier (BCB)of rats in order to provide the theo-rical basis for elucidating the mechanis m of lead induced neurotoxicity.MEHTODS 60 SPF SD rats were rando mly divided into 4 groups,including a control group and three doses lead exposed groups. Rat in the lead exposure groups were given drinking water containning 0.05%,0.1 % and 0.2% lead acetate (at dose of 80,160,320 mg·kg -1 )for 8 weeks.Laser scanning confocal microscopy was uti-lized to determine the lead content in seru m,cerebrospinal fluid (CSF)and choroid plexus sa mples. Morris maze was used to test learning and me mory.Fe moral artery perfusion of Evans blue (EB)and fluorescein sodiu m (NaFI)was performed to measure BCB permeability function.Confocal laser scan-ning was applied to detect junction adhesion molecule (JAM)and occludin protein expression in choroid plexus.ELISA was used to measure the concentration of transthyretin (TTR)and leptin in seru m and CSF.RESULTS The lead content in seru m,choroid plexus and CSF significantly increased,especially the lead level in CSF.Morris water maze data showed that escape latency of rat in lead acetate 160 and 320 mg·kg -1 group were 52 ±12,(89 ±19)s,respectively,longer than that of control group 〔(28 ±7)s, P<0.05〕.The ti mes across platform of rats in lead acetate 160 and 320 mg·kg -1 group were lower than that of control group(P <0.05).The NaFI content in CSF of rats in all lead acetate exposure groups were 0.94 ±0.09,1 .02 ±0.03 and (1 .08 ±0.18)mg·L -1 ,respectively,and were higher than those of control group〔(0.74 ±0.04)mg·L -1 〕;While the EB content in CSF of rat in lead acetate 160 and 320 mg·kg -1 group were higher than the control group(P <0.05),which indicated that lead acetate exposure at low dose can lead to the increase of permeability of BCB.Laser scanning confocal micro-scope i mages showed that the JAM protein expression of choroid plexus in lead acetate 160 and 320 mg·kg -1 group were 44.9% and 42.9% of the control group.Sa me decline was seen in terms of occludin expression.The TTR content of CSF of rats in lead acetate 80 mg·kg -1 group was (32.3 ± 1 1 .7)ng·g -1 protein,lower than that of the control group,and the difference was significant.This decline was also noted in lead acetate 160 and 320 mg·kg -1 group.The data of TTR in CSF suggested that the low dose lead acetate exposure can disrupt the BCB secretion function.The leptin levels in CSF of lead acetate 160 and 320 mg·kg -1 group were lower than that in the control group (P <0.05 ). CONCLUSION Lead exposure did disrupt the permeability,transportation and secretion function of BCB.Our data suggest that BCB dysfunction might be involved in the mechanis m of lead induced neurotoxicity.

Objective To detect the dynamic changes of the level of serum Clara cell protein(CC16)and surfactant protein-D(SP-D)in rats with pulmonary fibrosis induced by bleomycin and to evaluate their value in early diagnosis of pulmonary fibrosis. Methods Sixty Wistar rats were randomly divided into two groups, the control group and bleocin-induced pulmonary fibrotic group,with 30 rats in each group. The rats were killed at 1,3,7,14 and 28 days of treatment Pathology changes of lung tissue were observed by HE,Masson stain,alkaline hydrolysis to assess the hydroxyproline concentration of lung tissue, enzyme-linked immunosorbent assay (ELISA) was used to measure the levels of serum CC16 and SP-D. Results The hydroxyproline concentration of lung tissue in the pulmonary fibrotic group ((913. 1 ±69. 3) μg/g) were higher than those of the control group ((790. 5 ± 36. 8) μg/g) from the seventh day(P <0. 05). The levels of serum CC16 of the pulmonary fibrotic group((27. 34 ± 0. 32) μg/L) were lower than those of the control group((27. 85 ±0. 32)μg/L) since the third day(P<0. 05) ,and tended to decrease with the development of the disease. However,the levels of SP-D of the former group were always higher(P <0. 05), and tended to increase with the development of the disease. Conclusions The levels of serum CC16 and SP-D changed considerably in early-stage of pulmonary fibrosis, thus might be used as biomarker for early diagnosis and have some value for pathogenesis of pulmonary fibrosis.

BACKGROUNDAngiotensin-converting enzyme (ACE), the key enzyme of RAS, is expressed in abundance in lung. Recent studies show that it plays various biological roles and even contributes importantly to the carcinogenesis of malignant tumors. The aim of this study is to investigate whether the insertion (I)/deletion (D) polymorphism of ACE is related to the susceptibility, pathological type or staging of lung cancer.

METHODSDNA was extracted from the peripheral veinous blood derived from 47 lung cancer patients and 54 normal persons. The ACE genotype of each sample was amplified with PCR.

RESULTSThe frequencies of II, ID and DD genotype of ACE in lung cancer group were 0.447, 0.447 and 0.106 respectively, and the frequencies of I and D allele were 0.670 and 0.330 respectively. The frequencies of II, ID and DD geno-(type) of ACE in control group were 0.370, 0.556 and 0.074 respectively, and the frequencies of I and D allele were 0.648 and 0.352 respectively. There was no significant difference of ACE genotypes or alleles frequencies between the lung cancer and control groups. No significant difference of ACE genotypes or alleles frequencies was found between small cell lung cancer and non-small cell lung cancer groups or between the different staging groups of lung cancer patients.

CONCLUSIONSNo association is found between the polymorphism of ACE gene and the susceptibility, pathological type or clinical staging of lung cancer.