Cranio-maxillofacial computer aided system is discussed including its conception,study situation,design sig-nificance and system structure,and then the main problems and its solution project of the research is also expounded.The clinical application of the system can be treated craniofacial deformities perfectly,producing very good social and economic benefits.

Abstract: To investigate the status and influencing factors of tooth loss among the elderly population in China, so as to provide insights into early prevention of tooth loss. Methods: Based on the Chinese Longitudinal Healthy Longevity Survey (CLHLS), data of the elderly people aged 65 years and older who participated in the survey in 2018 were collected, including demographic information, lifestyle, dietary habits, medical history, number of teeth remaining and self-assessment indicators. The status of tooth loss among the elderly were described based on the standard of 28 teeth, and factors affecting tooth loss were analyzed using a multivariable ordinal logistic regression model. Results: A total of 5 260 people was recruited, including 3 346 males (63.61%) and 1 914 females (36.39%). The median age was 78.00 (interquartile range, 18.00) years. The median number of teeth remaining was 12.00 (interquartile range, 23.00), and the median number of missing teeth was 16.00 (interquartile range, 23.00). Multivariable ordinal logistic regression analysis showed that the elderly who were female (OR=1.270, 95%CI: 1.098-1.470), had advanced age (OR=1.090, 95%CI: 1.083-1.098), lived in rural areas (OR=1.369, 95%CI: 1.165-1.610) and urban areas (OR=1.208, 95%CI: 1.027-1.422), smoked (past, OR=1.471, 95%CI: 1.240-1.746; always, OR=1.545, 95%CI: 1.300-1.838) and brushed teeth less than once a day (OR=1.791, 95%CI: 1.488-2.160) had more missing teeth; while the elderly who had high levels of education (junior high school, OR=0.819, 95%CI: 0.681-0.972; high school, OR=0.626, 95%CI: 0.507-0.771; college and above, OR=0.468, 95%CI: 0.334-0.657), kept physical exercise (OR=0.840, 95%CI: 0.736-0.958) and were overweight/obese (OR=0.868, 95%CI: 0.769-0.980) had less missing teeth. Conclusion Gender, age, residence, educational level, smoking, physical exercise, teeth brushing frequency and overweight/obese are the influencing factors for tooth loss among the elderly in China.

The two important methods for displaying three-dimensional data called surface rendering and volume rendering are introduced and analyzed.It is concluded that volume rendering is superior to surface rendering for the former one provides a basis for visualization of three-dimensional data.

The paper puts forward the design and application of an imaging analysis system for micro-particles.The structure of the system,design theory and its application are discussed in the paper.

This paper introduces the method of electron tomography three-dimensional reconstruction,which is widely applied in structural biology field and summarizes its advantages and disadvantages.The aim is to provide a reference for the application of the method.

Objective To obtain the expression pattern of imprint gene H19 in JEG-3 cell in order to explore the regulation mechanism of H19 on trophoblast cellular biological behavior .Methods After correct identification with sequencing for the recom-binant eukaryotic expression plasmid pRc/CMV which including the whole length of H19 cDNA ,the plasmid was transfected to the cell line JEG-3 .The expression of H19 mRNA was observed and the gene expression profile of three groups of JEG-3 cell were de-tected with Affymetri :U133 plus 2 .0 Array .Results After being transfected with target H 19 gene ,the expression of the mRNA level was significantly increased compared with control group .And the gene expression profile was changed significantly .19 genes were up-regulated ,77 genes were down-regulated .Expression levels of HES1 gene which being choosed as a different expression gene were detected by fluorescence quantitative PCR in severe preeclampsia placenta tissue and normal late pregnant placenta .The expression level of HES1 mRNA in severe preeclampsia placenta decreased significantly than normal late pregnant placenta tissues . Conclusion Many genes induced by H19 have been screened by high-throughput gene chip method .It provides the experimental ba-sis for advanced studying the regulation the cellular biological behavior with H 19 gene .

Objective To explore the role of H19 imprinting in etiology of pre-eclampsia. Methods Placentas of 24 women with pre-eclampsia (3 with mild pre-eclampsia and 21 with severe pre-eclampsia) and 50 healthy pregnant women at full term (control) were collected during selected cesarean delivery between August 2007 and March 2008. The statuses of H19 imprinting with placental tissues from normal pregnancy and patients with pre-eclampsia were identified upon polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The systolic and diastolic pressure were analyzed in H19 heterozygotic women. Results (1) There were 20 (40%) heterozygotes in 50 cases placenta tissues of the third trimesters, 11 (45%) heterozygotes in 24 cases placenta tissues of pre-eclampsia, There were no significant difference between two groups ( P > 0.05 ). (2) All 20 heterozygotes in placenta tissues of the third trimesters are exclusively monoallelically expressed, while 5 cases (45%) in 11 heterozygotes of pre-eclampsia are biallelically expressed (loss of imprinting, LOI). There were significant difference between two groups (P < 0. 01 ). (3) The values of systolic and diastolic pressure of patients with monoallelic expression of H19 were (171 ±9) mm Hg (1 nun Hg =0.133 kPa) and ( 104±8) mm Hg, the values of systolic and diastolic pressure with biallelic expression were ( 194±21 ) mm Hg and ( 124±18) mm Hg. There were significant difference between two groups (P<0.05 ). Conclusion LOI of H19 can be identified in pre-eclamptic placentas and is associated with maternal blood pressures, which implies the involvement of H19 gene LOI in the pathogenesis of pre-eclampsia and its potential relationship with the severity of the disease.

The scientificalness of page quality assessment was improved by adding the page vote fraction and the user satisfaction with page according to the time perception-based PageRank Algorithm. The individualized retrieval was realized by adding the users-interested model that was matched with page types and by moving up the users-interested page rank.

Objective To investigate the effect of dipeptidyl peptidase-4 (DPP-4) inhibitor on lipopolysaccharide (LPS)-induced changes in the mass and function of pancreatic β-cells.Methods RINm cells were cultured and treated with LPS alone or combined with different concentrations of sitagliptin for 24 h.The proliferation of RINm cells was detected by CCK-8 assay.Apoptotic rate was determined by Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide flow cytometry.Insulin secretion was measured by enzyme-linked immunosorbent assay.The expression of IL-6 mRNA was displayed by RT-PCR.Results LPS significantly stimulated the proliferation of RINm cells (0.89 ± 0.04 vs 1.14 ± 0.08,P＜0.01),while LPS+sitagliptin showed no significant difference compared with LPS group.The cell apoptotic rate in LPS + 10-1 mmol/L sitagliptin group was significantly lower than that in LPS group.There were no significant differences in basal insulin secretion among all groups,but after the high/low glucose stimulation,LPS increased insulin secretion as compared with the control.The IL-6 mRNA expression in LPS+sitagliptin group was significantly lower than that in LPS group (0.77 ± 0.33 vs 1.30 ± 0.41,P =0.006).Conclusions DPP-4 inhibitor has no influence on LPS-induced proliferation of pancreatic β-cell,but it can inhibit LPS-induced apoptosis and insulin secretion,and IL-6 may be involved in the process.

Objective To investigate the effect of tube voltage and iodine concentration of contrast medium (CM) on abdominal dynamic enhanced CT image quality.Methods Six miniature pigs underwent repeated upper abdomen dynamic contrast-enhanced CT scans in 4 scanning protocols with different concentration of CM and tube voltage,namely,protocol 1,CM with iodine concentration of 270 milligrams iodine per milliliter (mg/ml) and 80 kV tube voltage;protocol 2,270 mg/ml and 120 kV;protocol 3,370 mg/ml and 80 kV and protocol 4,370 mg/ml and 120 kV.The same iodine dose (600 mg/ml) and iodine delivery rate (IDR) (920 mg/s) were used in all protocols.The CM with iodine concentration of 270 mg/ml were injected at a flow rate of 3.4 ml/s,and 370 mg/ml CM injected at 2.5 ml/s.Image reconstruction was performed with iterative reconstruction (iDose4) in protocol 1 and 3,filtered back projection (FBP) was used in protocol 2 and 4.A subjective scoring system for image quality,image noise and sharpness was conducted by 2 radiologists independently.The measured values (peak of enhanced CT values,image noise of aorta,inferior vena cava,portal vein,hepatic vein and liver parenchyma) as well as the calculated values [their time-to-peak,signal-to-noise (SNR) and contrast-to-noise (CNR) ratios] were compared between among 4 protocols.The CT volume dose index (CDTIvol) and dose length product (DLP) were recorded from the CT console after each scanning.Factorial designed ANOVA was used for comparison of enhanced CT values of vessels and liver parenchyma,noise,SNR and CNR.The Kruskal-Wallis test was used for comparison of values among the 4 protocols,including the time-to-peak enhancement of vessels and liver parenchyma,the subjective scores of image quality indices.Result There was no significant differences in subjective scores of the image quality,image noise and image sharpness (P＞0.05).The scored were more than 3,and the images with 4 scanning protocols were all acceptable for diagnosis.There was no significant differences between protocol 1 and 3,protocol 2 and 4 in the peak enhancement CT values of aorta [(729±46) HU vs.(707±59)HU,(515±84)HU vs.(513±53)HU],inferior vena cava [(366±95)HU vs.(368±92)HU,(282±39)HU vs.(262 ± 67)HU],portal vein [(213± 18)HU vs.(201 ±29)HU,(180±21)HU vs.(176±27)HU],hepatic vein [(207±18)HU vs.(193±10)HU,(179±24)HU vs.(170±14)HU] and liver parenchyma [(128±7) HU vs.(127±4) HU,(135±5)HU vs.(135±6)HU] (P＞0.05).But the CT values of vessels (aorta,inferior vena cava,portal vein and hepatic vein) in protocol 1 and 3 were significantly higher than those in protocol 2 and 4 (P＜0.05),the CT values of liver parenchyma in protocol 1 and 3 were significantly lower than values in protocol 2 and 4 (P＜0.05).The image noises of vessels were higher in protocol 1 and 3 than noises in other protocols (P＜0.05),but there was no significant difference in liver parenchyma noise among protocols (P＞0.05).No significant differences were observed on the peak times,SNR and CNR in aorta,inferior vena cava,portal vein,hepatic vein and liver parenchyma among 4 protocols (P＞0.05).The CDTIvol and DLP were 199.67 mGy,1 597.4 mGy· cm respectively in protocol 1 and 3,585.12 mGy and 4 680.9 mGy· cm in protocol 2 and 4 (scanning with 120 kV).Conclusions CM with different iodinated concentration could achieve the same enhancement in the abdominal vessels and liver parenchyma by using the proper scan protocols,which have the same IDR and iodine dose per kilogram body weight.Higher vessel enhanced peak values were achieved when using the protocols with 80 kV tube voltage than 120 kV.By using a low dose protocol of 80 kV tube voltage with the iterative reconstruction algorithm,the quality of image can be warranted.