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1.
研究目的：探讨同一患者不同时期所拍的锥形束计算机断层摄影（CBCT）是否因每次拍摄时投照角度不可能完全一致而影响数据测量的准确性。创新要点：提出了一种人类后牙拔除后观察牙槽突外形变化的准确、无创、科学的定位方法。研究方法：选择首都医科大学附属北京口腔医院种植中心60名患者两份于上颌后牙种植前后拍摄的CBCT影像资料。以磨牙根分叉区三个牙根开始分开处（图像上显示为三根恰好融合的点）为基准点定位两次CBCT的起始水平断层。在第一次CBCT的起始水平断层上,连线牙列远端磨牙参照点即矢状断层起点与近端双尖牙的髓室中心进行矢状断层重建。若实验牙为第一磨牙,找到通过其腭根髓室中心的矢状断层;若实验牙为第二双尖牙,找到通过其髓室中心的矢状断层。记录由矢状断层起点到实验牙移动的层数N,在水平断层上测量实验牙牙槽骨宽度,在实验牙髓室中心的矢状断层上测量牙全长。在第二次CBCT中依据第一次记录的移动层数N定位矢状断层,在定位后的矢状断层上测量实验牙全长,在水平断层的相应定位处测量牙槽骨宽度。重要结论：利用本研究提出的定位方法可以精准定位同一患者不同CBCT影像资料中的同一断层,从而实现拔牙位点动态连续观察。  相似文献   

2.
研究目的：创新要点：研究方法：重要结论：观察人类上颌中切牙拔除后牙槽骨外形改建的规律。锥形束计算机断层摄影（CBCT）在口腔硬组织测量方面具有可靠性,在不同时期拍摄的影像中测量具有可重复性。本研究充分利用这一影像学工具观察人类上颌中切牙拔除后牙槽骨改建的规律。选择40名患者上颌中切牙拔牙前和拔牙后三个月时拍摄的两份CBCT影像资料。在第一次CBCT中,选取中切牙拔牙窝深、中、浅三个水平断层进行矢状断层重建,分别记录矢状断层起点到拟拔除中切牙（实验牙T）牙髓中心移动的层数,并测量实验牙T处牙槽骨宽度,在中切牙拔牙窝中层测量腭平面相关垂直距离。在第二次CBCT的三个水平断层上,依据第一次记录的移动层数定位实验牙T,并在定位处测量牙槽骨宽度。在中切牙拔牙窝中层上转移第一次CBCT记录的腭平面相关距离,并测量唇腭侧牙槽嵴顶沿原牙根外形垂直吸收的距离。上颌中切牙拔除后三个月,在拔牙窝的不同深度,唇侧的牙槽骨均有不同程度的水平骨吸收,越接近牙槽嵴项处牙槽骨吸收越明显。唇腭侧牙槽嵴顶均有明显的垂直骨吸收,唇侧牙槽嵴项的垂直骨吸收比腭侧明显。  相似文献   

3.
Early studies had suggested that vitamin D intake was inversely associated with neurodegenerative diseases, such as Alzheimer’s disease and multiple sclerosis. However, the associations of vitamin D intake and outdoor activities with Parkinson’s disease (PD) are still unclear, so this study is to evaluate these relationships from a case-control study in elderly Chinese. The study population involved 209 cases with new onsets of PD and 210 controls without neurodegenerative diseases. The data on dietary vitamin D and outdoor activities were collected using a food-frequency questionnaire and self-report questionnaire. Multivariable logistic regressions were used to examine the associations between dietary outdoor activities, vitamin D intake and PD. Adjustment was made for sex, age, smoking, alcohol use, education, and body mass index (BMI). Adjusted odds ratios (ORs) for PD in quartiles for outdoor physical activity were 1 (reference), 0.739 (0.413, 1.321), 0.501 (0.282, 0.891), and 0.437 (0.241, 0.795), respectively (P=0.002 for trend). Adjusted ORs for PD in quartiles for total vitamin D intake were 1 (reference), 0.647 (0.357, 1.170), 0.571 (0.318, 1.022), and 0.538 (0.301, 0.960), respectively (P=0.011 for trend). Our study suggested that outdoor activity and total vitamin D intake were inversely associated with PD, and outdoor activity seems to be more significantly associated with decreased risk for PD.  相似文献   

4.
A number of studies have identified correlations between children’s stereotypes of scientists, their science identities, and interest or persistence in science, technology, engineering, and mathematics. Yet relatively few studies have examined scientist stereotypes among college students, and the literature regarding these issues in predominantly nonwhite and 2-yr college settings is especially sparse. We piloted an easy-to-analyze qualitative survey of scientist stereotypes in a biology class at a diverse, 2-yr, Asian American and Native American Pacific Islander–Serving Institution. We examined the reliability and validity of the survey, and characterized students’ comments with reference to previous research on stereotypes. Positive scientist stereotypes were relatively common in our sample, and negative stereotypes were rare. Negative stereotypes appeared to be concentrated within certain demographic groups. We found that students identifying nonstereotypical images of scientists at the start of class had higher rates of success in the course than their counterparts. Finally, evidence suggested many students lacked knowledge of actual scientists, such that they had few real-world reference points to inform their stereotypes of scientists. This study augments the scant literature regarding scientist stereotypes in diverse college settings and provides insights for future efforts to address stereotype threat and science identity.  相似文献   

5.
Learning bone anatomy of the skull is a complex topic involving three-dimensional information. The impact of the use of human dry skulls and cone beam computed tomography (CBCT) imaging was investigated in the teaching of undergraduate dental students. Sixty-four first-year students in the University of Hong Kong were randomly divided into eight groups. Four teaching methods were tested: (1) CBCT followed by standard lecture, (2) CBCT followed by lecture with skulls, (3) standard lecture followed by CBCT, and (4) lecture with skulls followed by CBCT. After each, students were given a multiple-choice questionnaire to assess their objective learning outcome (20 questions) and a questionnaire for their subjective satisfaction (10 statements). Surveys were assessed with Cronbach's alpha, Kendall's tau-b, and principal components analysis. Data were analyzed with Student's t-test and a one-way ANOVA (significance α = 0.05). Standard lecture followed by CBCT showed the highest learning outcome score (81.6% ± 14.1%), but no significant difference was present among four teaching methods. Cone beam computed tomography followed by lecture with skulls scored the highest overall subjective satisfaction (4.9 ± 0.8 out of 6), but no significant difference was present among teaching methods. Nevertheless, students' perception of learning was positively influenced by the use of skulls (P = 0.018). The timing of administration of the CBCT did not affect students' subjective satisfaction or objective learning outcome. Students perceived to learn more by using skulls, but their objective learning outcomes were not significantly affected. A discrepancy seems to exist between students' perception of learning and their effective performance.  相似文献   

6.
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7.
E-learning is an educational method that improves knowledge innovation by sharing relevant images for advanced learning, especially in a pandemic state. Furthermore, cone-beam computed tomography (CBCT) is a method that gathers medical or dental diagnostic images. This study aimed to analyze the effectiveness of dental anatomy education through a CBCT technology tool, through teachers' and students' perspectives, adjusted according to the disruptions caused by the Covid-19 pandemic. A cohort study and longitudinal exploratory analysis were performed. Forty undergraduate first-year dental students, from the University of Coimbra in Portugal, were selected as per the inclusion and exclusion criteria. Two different teaching methods were applied during an identical time-period: face-to-face lectures complemented by physical models (T1 cohort) and webinar lectures complemented by CBCT images (T2 cohort). Learning outcomes were then studied according to theoretical and spatial orientation contexts. A self-reported survey that focused on students' satisfaction, stress, and support was studied. Both teaching methods were analyzed with paired sample student's t-test and Pearson Correlation Confidence intervals 95% with P < 0.05. Furthermore, exploratory factor analysis (EFA) was used for self-reported satisfaction survey validity and reliability analysis. The learning outcomes between T1 and T2 cohorts were statistically significant, (P < 0.001) corresponding to differences with a large effect degree (r > 0.60). Students' satisfaction, as measured on a six-point Likert scale, was positively influenced by the webinar lectures supplemented with CBCT images (T2 cohort) in a learning context (4.95 ± 0.5) and future applications (5.92 ± 0.27). In conclusion, the webinar approach with CBCT images was more effective and better learning method for teaching dental anatomy.  相似文献   

8.
The population genetic data and forensic parameters of 19 X-chromosome short tandem repeat (X-STR) loci in Chinese Uygur ethnic minority are presented. These loci were detected in a sample of 233 (94 males and 139 females) unrelated healthy individuals. We observed 238 alleles at the 19 X-STR loci, with the corresponding gene frequencies spanning the range from 0.0021 to 0.5644. After Bonferroni correction (P>0.0026), there were no significant deviations from Hardy-Weinberg equilibrium. The cumulative power of discrimination in females and males, and the probability of exclusion of the 19 X-STR loci were 0.999 999 999 999 999 999 998 091, 0.999 999 999 999 966, and 0.999 999 986 35, respectively. The cumulative mean exclusion chance was 0.999 999 992 849 in deficiency cases, 0.999 999 999 999 628 in normal trios, and 0.999 999 998 722 in duo cases. The high value of the forensic parameters mentioned above revealed that the novel panel of 19 loci had important values for forensic applications in the Uygur group.  相似文献   

9.
Minimally invasive endoscopic resection has been rapidly adopted as a new technique for treating patients with gastric submucosal tumors (SMTs) originating in the muscularis propria (MP) layer. This study was conducted to evaluate the information obtained from endoscopic ultrasonography (EUS) to determine the appropriate endoscopic dissection method for treating SMTs originating in the MP layer. Between February 2014 and May 2016, a total of 50 patients with gastric SMTs originating in the MP layer were enrolled in this study. The clinical features of the patients and their endoscopic, EUS, and histopathologic findings, as well as their postoperative follow-up data, were analyzed in this retrospective study. The mean age of the patients was (55.0±10.2) years, and the male/female ratio was 17:33. Endoscopic submucosal dissection (ESD) was performed on 43 patients and an endoscopic full-thickness resection (EFR) was performed on seven patients. The most frequent location for an SMT was in the upper body region of the stomach (n=16), and the most common pathological diagnosis was a gastrointestinal stromal tumor (GIST) (n=32). The overall rates for complete resection were 95.3% (41/43) and 100.0% (7/7) when the SMTs were treated by ESD and EFR, respectively. The presence of a complete tumor capsule was significantly associated with a complete resection (P=0.001). Of the cases treated by ESD, nine patients developed perforation, one of whom required laparoscopic surgery. The remaining patients were closed with clips or purse-string sutures. The presence of an MP2-type tumor (P=0.018) and a wide connection with the MP layer (P=0.044) were significantly associated with perforation. A preoperative evaluation of the integrity and the location of a tumor capsule and the length of the tumor connection with the MP layer by EUS can improve the complete resection rate and reduce the occurrence of intraoperative complications. Tumors with a complete capsule originating from the superficial MP layer or with a narrow connection with the MP layer are appropriate candidates for treatment by ESD.  相似文献   

10.
The objective of this study was to examine the associations between attendance at childbirth education classes and maternal characteristics (age, income, educational level, single parent status), maternal psychological states (fear of birth, anxiety), rates of obstetric interventions, and breastfeeding initiation. Between women’s 35th and 39th weeks of gestation, we collected survey data about their childbirth fear, anxiety, attendance at childbirth education classes, choice of health-care provider, and expectations for interventions; we then linked women’s responses (n = 624) to their intrapartum records obtained through Perinatal Services British Columbia. Older, more educated, and nulliparous women were more likely to attend childbirth education classes than younger, less educated, and multiparous women. Attending prenatal education classes was associated with higher rates of vaginal births among women in the study sample. Rates of labor induction and augmentation and use of epidural anesthesia were not significantly associated with attendance at childbirth education classes. Future studies might explore the effect of specialized education programs on rates of interventions during labor and mode of birth.  相似文献   

11.
To our knowledge, few reports on Demodex studied at the molecular level are available at present. In this study our group, for the first time, cloned, sequenced and analyzed the chitin synthase (CHS) gene fragments of Demodex folliculorum, Demodex brevis, and Demodex canis (three isolates from each species) from Xi’an China, by designing specific primers based on the only partial sequence of the CHS gene of D. canis from Japan, retrieved from GenBank. Results show that amplification was successful only in three D. canis isolates and one D. brevis isolate out of the nine Demodex isolates. The obtained fragments were sequenced to be 339 bp for D. canis and 338 bp for D. brevis. The CHS gene sequence similarities between the three Xi’an D. canis isolates and one Japanese D. canis isolate ranged from 99.7% to 100.0%, and those between four D. canis isolates and one D. brevis isolate were 99.1%–99.4%. Phylogenetic trees based on maximum parsimony (MP) and maximum likelihood (ML) methods shared the same clusters, according with the traditional classification. Two open reading frames (ORFs) were identified in each CHS gene sequenced, and their corresponding amino acid sequences were located at the catalytic domain. The relatively conserved sequences could be deduced to be a CHS class A gene, which is associated with chitin synthesis in the integument of Demodex mites.  相似文献   

12.
In our secondary analysis of a cross-sectional survey, we explored predictors of childbirth fear for young women (n = 2,676). Young women whose attitudes toward pregnancy and birth were shaped by the media were 1.5 times more likely to report childbirth fear. Three factors that were associated with reduced fear of birth were women’s confidence in reproductive knowledge, witnessing a birth, and learning about pregnancy and birth through friends. Offering age-appropriate birth education during primary and secondary education, as an alternative to mass-mediated information about birth, can be evaluated as an approach to reduce young women’s childbirth fear.  相似文献   

13.
A preschooler's ability to delay gratification in the waiting task is predictive of several developmental outcomes, despite this task's relatively low reliability level. Success in this task depends on the use of distraction strategies. The new Watch-and-Wait Task (WWT) has been developed to enhance reliability and to investigate whether the waiting situation is equally predictive if distraction from the reward is inhibited. To prevent distraction in the WWT, children were instructed to watch an hourglass run out during the waiting period. In a reliability analysis (n = 31) the WWT showed acceptable retest reliability. In a second study (n = 61), the time preschoolers spent waiting in the WWT was associated with later academic achievement and behavioral problems diagnosed at the end of grade 1, even after controlling for intelligence, gender and age. Overall, the WWT proved to be a reliable instrument predictive of children's behavioral and academic development.  相似文献   

14.
基于序列图像的鱼类机动性分析系统(英文)   总被引：3，自引：0，他引：3  
为了建立一个研究鱼类机动性的自动化分析系统,使用高速摄像机(1 000 frame/s)记录了鱼的快速起动过程,并进行动力学分析.首先确定并等分第1帧图中鱼的中轴线,保存等分点坐标;然后运用图像相关在下一帧图中找出第1帧图中的所有等分点,并用样条函数拟合这些等分点,得到鱼的中轴线,重复这一步骤,获得序列图像中鱼的中轴线;最后根据中轴线随时间的变化分析计算鱼在起动过程中的运动特性.运用此系统,测试了鲤鱼的C形起动过程,鲤鱼C形起动分为2个阶段:第1阶段,整个身体弯曲成C形;第2阶段,尾鳍做大幅度反向摆动,然后鲤鱼做直线运动.通过对各个阶段鱼体中轴线的跟踪,获得了鲤鱼C形起动的转动角速度、质心转速和质心转动半径等运动学参数.  相似文献   

15.
ABSTRACT

The purpose of the study was to assess the role of market orientation (MO), mediated by job satisfaction (JS) and its effect on market performance (MP) in Ghana’s private universities. A sample of 205 senior staff of 15 private universities was selected to participate in the study, using a convenience sampling method. Partial Least Squares (PLS) of Structural Equation Modelling (SEM) was used to test the relationships in the study. The results found a significant positive relationship between MO and MP on one hand; Job satisfaction (JS) and MP on the other. Finally, the study found that JS mediates the relationship between MO and MP. The study provides a useful guide to marketing strategy especially the implementation of MO to enhance performance in Ghana’s private universities. The study has practical application to private universities seeking to compete favourably in a competitive environment.  相似文献   

16.
提出了一种改进的二次曲线轮廓度误差的评定方法。以最小二乘曲线的焦点坐标作为中心划分正方形网格,在其中按一定规则设定标志点,若标志点配对拟合曲线计算所得轮廓度误差过大就将其剔除。然后在误差较小的区域进一步细分网格并配对拟合曲线,再以多次迭代运算的方法最终求得最小条件法下的轮廓度误差值。该方法搜索速度快,计算精度高,适用于任意平面二次曲线的轮廓度误差评定,辅以MATLAB软件实现误差求解的可视化,最后实例证明该算法的可靠性。  相似文献   

17.
This study investigates the reliability and validity of the Child Care Ecology Inventory (CCEI), a measure of the quality of family child care in the social domain. The CCEI focuses on research-based environmental features and caregiving practices for promoting positive social development in preschool-age children. A total of 198 family child care homes in the Northwest USA participated. Good scale reliabilities were found for the measures of the environment (Enrichment and Organization) and for caregivers’ practices (Monitoring, Positive Attention, Promoting Social Skills, and Teaching Rules) and interrater reliability was adequate for research purposes. The CCEI was associated with other commonly used measures of child care quality that assessed similar environmental and caregiving constructs. Linear regression models were run to determine the features of family child care quality that were concurrently associated with observed child behavior. The child–caregiver ratio, Environment Organization, and caregivers’ Teaching Rules were negatively associated with children's problem behavior (noncompliance and aggression). Caregivers’ provision of Planned Activities/Routines and Positive Attention were associated with positive child behavior. Results indicate that different aspects of quality are related to different aspects of children's social interactions and behaviors.  相似文献   

18.
Published evaluations of career preparation of alumni from long-standing postdoctoral fellowship programs in the biomedical sciences are limited and often focus on quantitative analysis of data from extant publicly available sources. Qualitative methods provide the opportunity to gather robust information about specific program elements from structured postdoctoral training programs and the influence of this training on subsequent career paths of alumni. In-depth interviews with a subset of the National Cancer Institute’s Cancer Prevention Fellowship Program (CPFP) alumni (n = 27), representing more than 25 years of the program’s history and multiple career sectors, were conducted to assess alumni reflections on the training environment and career preparation during their time in the CPFP. NVivo software was used to analyze data and identify major themes. Four main themes emerged from these interviews, including: the value of structured training curriculum, mentorship, transdisciplinary environment, and professional identity. Even when reflecting on training that occurred one to two decades earlier, alumni were able to highlight specific components of a structured postdoctoral training program as influencing their research and career trajectories. These results may have relevance for those interested in assessing how postdoctoral training can influence fellows throughout their careers and understanding salient features of structured programs.  相似文献   

19.
Objective: XRCC1 polymorphism is a research hotpot in individual treatment for non-small cell lung cancer (NSCLC). To obtain the association between XRCC1 polymorphism and clinical outcome of platinum-based treatment for NSCLC, a meta-analysis was conducted. Methods: Databases including PubMed, Embase, Cochrane, and Chinese National Knowledge Infrastructure (CNKI) were searched for publications that met the inclusion criteria. A fixed effect model was used to estimate pooled odds ratio (OR) and hazard ratio (HR) with 95% confidence interval (CI) for the association between XRCC1 Arg399Gln and response or survival of platinum-based treatment for advanced NSCLC. A chi-squared-based Q-test was used to test the heterogeneity hypothesis. Egger’s test was used to check publication bias. Results: Seventeen published case-control studies that focus on the association between XRCC1 Arg399Gln and response or survival of platinum-based treatment for advanced NSCLC in 2 256 subjects were included in this meta-analysis, of whom 522 were AA genotypes (23.2% frequency), 916 AG genotypes (40.6% frequency), and 818 GG genotypes (36.2% frequency). The overall response rate (ORR) was 45.2% (110/243) for AA genotype patients, 29.9% for AG genotype (73/244), and 30.7% for GG genotype (124/403). The heterogeneity test did not show any heterogeneity and the Egger’s test did not reveal an obvious publication bias among the included studies. The meta-analysis indicated that AA genotype patients presented higher response rates toward platinum drug treatment compared with G model (GG+GA) patients (GG vs. AA model: OR=0.489, 95% CI 0.266–0.900, P=0.021; AG vs. AA model: OR=0.608, 95% CI 0.392–0.941, P=0.026; GA+AA vs. GG model: OR=1.259, 95% CI 0.931–1.701, P=0.135; GG+GA vs. AA model: OR=0.455, 95% CI 0.313–0.663, P=0.0001). However, no evidence validates XRCC1 associates with the survival following platinum drug therapy. Conclusions: Our meta-analysis suggested that XRCC1 Arg399Gln is related with the sensitivity of NSCLC patients to platinum-based treatment. AA genotype patients present more desirable curative effectiveness compared with other patients.  相似文献   

20.
Children’s picture books that recreate, parody, or fictionalize famous artworks and introduce the art museum experience, a genre to which I will refer as “children’s art books,” have become increasingly popular over the past decade. This essay explores the pedagogical implications of this trend through the family program “Picture Books and Picture Looks” conducted at the Art Institute of Chicago. Program sessions were observed to learn the extent to which picture books featuring the painting A Sunday on La Grande Jatte—1884 (Seurat) informed and impacted children’s experiences with the original artwork. The books Katie’s Sunday Afternoon (Mayhew, 2005), Babar’s Museum of Art (De Brunhoff, 2003), and Willy’s Pictures (Browne, 2000) provided the foundation for the program. In addition to these three books, The Dot (Reynolds, 2003), which does not include a reference to La Grande Jatte (Seurat, 1884–1886), acted as a “control” variable. This research demonstrates that while most picture books can be used to establish a level of comfort in an environment that is new to children, those that directly referenced the painting provided a base level of knowledge from which children could confidently draw upon encountering the original work. The research further indicated that, when used in conjunction with original artworks, children’s art books provide unique and distinct entry points for talking about art. The inclusion of artwork in children’s picture books elicits an enthusiasm and recognition that enhances the museum experience, and such books can be effective tools for enabling reflective, imaginative experiences with art.  相似文献   

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