A Novel Similarity Learning Method via Relative Comparison for Content-Based Medical Image Retrieval

Nowadays, the huge volume of medical images represents an enormous challenge towards health-care organizations, as it is often hard for clinicians and researchers to manage, access, and share the image database easily. Content-based medical image retrieval (CBMIR) techniques are employed to facilitate the above process. It is known that a few concrete factors, including visual attributes extracted from images, measures encoding the similarity between images, user interaction, etc. play important roles in determining the retrieval performance. This paper concentrates on the similarity learning problem of CBMIR. A novel similarity learning paradigm is proposed via relative comparison, and a large database composed of 5,000 images is utilized to evaluate the retrieval performance. Extensive experimental results and comprehensive statistical analysis demonstrate the superiority of adopting the newly introduced learning paradigm, compared with several conventional supervised and semi-supervised similarity learning methods, in the presented CBMIR application.     

Relative Rigidity of Cell–Substrate Effects on Hepatic and Hepatocellular Carcinoma Cell Migration

Abstract

Polyacrylamide gels with different stiffness and glass were employed as substrates to investigate how substrate stiffness affects the cellular stiffness of adherent hepatocellular carcinoma (HCCLM3) and hepatic (L02) cells. The interaction of how cell-substrate stiffness influences cell migration was also explored. An atom force microscope measured the stiffness of HCCLM3 and L02 cells on different substrates. Further, F-actin assembly was analyzed using immunofluorescence and Western blot. Finally, cell-surface expression of integrin β1 was quantified by flow cytometry. The results show that, while both HCCLM3 and L02 cells adjusted their cell stiffness to comply with the stiffness of the substrate they were adhered to, their tuning capabilities were different. HCCLM3 cell stiffness complied when substrate stiffness was between 1.1 and 33.7 kPa, whereas the analogous stiffness for L02 cells occurred at a higher substrate stiffness, 3.6 kPa up to glass. These ranges correlated with F-actin filament assembly and integrin β1 expression. In a migration assay, HCCLM3 cells migrated faster on a relatively soft substrate, while L02 cells migrated faster on substrates that were relatively rigid. These findings indicate that different tuning capabilities of HCCLM3 and L02 cells may influence cell migration velocity on substrates with different stiffness by regulating cy- toskeleton remodeling and integrin β1 expression.     

Development of a coronavirus social distance attitudes scale

ObjectiveOur goal was to develop a scale to assess social distance attitudes related to COVID-19.MethodsWe performed an online national survey of US adults (n = 1,074) to assess social distance attitudes, COVID-19 related beliefs and behaviors, and demographics. We assessed scale structure using confirmatory factor analysis and evaluated internal consistency and validity. We assessed association of scale factors with respondent characteristics.ResultsConfirmatory factor analysis supported a hypothesized two-factor solution. Internal consistency was high for both positive (Alpha = 0.92) and negative (Alpha = 0.91) attitude factors. Analyses supported construct and predictive validity with expected associations between scale factors and perceived norms and behavior (e.g. trips out of the home). We found an interaction suggesting that holding highly negative attitudes reduced the effect of holding positive beliefs. Both attitude factors were related to age, gender, race/ethnicity, and political affiliation. Perceived COVID-19 risk (to others but not for self) and perceived severity were consistently associated with higher positive and lower negative attitudes.ConclusionThis COVID-19 Social Distance Attitude Scale contains positive and negative factors with high internal consistency and construct and predictive validity.Practice implicationA greater understanding and ongoing assessment of COVID-19 social distance attitudes could inform policymakers, researchers, and clinicians who seek to promote protective social distance behaviors.     

基于锥形束CT对邻面接触区釉质厚度的测量与分析

目的    应用锥形束CT（cone beam computed tomography,CBCT）测量上下颌牙列邻面接触区釉质厚度及邻接点距离牙合面和釉牙骨质界的垂直高度,为临床邻面去釉提供参考数据。方法    选取2019年6—10月于吉林大学口腔医院医学影像科行CBCT检查患者50例,根据纳入标准选取符合测量条件的牙齿145颗,运用Invivo软件测量每颗牙齿邻面接触区的釉质厚度及邻接点距离牙合面和釉牙骨质界的垂直高度。结果    从切牙至第一磨牙邻面接触区釉质厚度有逐渐增大的趋势;大多数牙位的远中邻面接触区釉质厚度大于近中（P < 0.05）,仅有上颌第一前磨牙和下颌第一磨牙的近远中邻面接触区釉质厚度差异无统计学意义（P > 0.05）;上下颌左右侧同名牙邻面接触区釉质厚度差异无统计学意义（P > 0.05）;除上颌中切牙-侧切牙、上下颌侧切牙-尖牙邻面接触区外,其余相邻牙齿近远中邻面接触区釉质厚度相似,差异均无统计学意义（均P > 0.05）;上颌邻面接触区平均釉质厚度大于下颌,差异有统计学意义（P < 0.05）;上下颌近远中邻接点到牙合面的垂直距离均小于到釉牙骨质界的垂直距离（均P < 0.05）。结论    不同牙位近远中邻面接触区釉质厚度不同,邻接点距离牙合面和釉牙骨质界的垂直高度也不同,临床邻面去釉时不同牙位去釉量不能按照同一标准进行,应结合CBCT影像资料制定个体化治疗方案。     

曲面体层片与锥形束CT比较分析上颌后牙牙根与上颌窦的关系

目的研究曲面体层片与锥形束CT(cone beam computer tomography,CBCT)判断上颌后牙牙根与上颌窦关系的准确性,为临床医师根据曲面体层片信息治疗上颌后牙区相关疾病提供参考。方法纳入80例符合标准的患者(牙根数671个),以锥形束CT为标准,在曲面体层片及锥形束CT片上测量上颌后牙根尖到上颌窦的距离。结果当曲面体层片显示上颌窦的皮质骨连续,牙根距上颌窦存在明显距离、与上颌窦相切时,曲面体层片判断上颌后牙牙根与上颌窦关系的准确率分别为82.0%、70.0%;当曲面体层片显示上颌窦皮质骨中断,牙根突入上颌窦内时,曲面体层片判断上颌后牙牙根与上颌窦关系的准确率为48.5%。曲面体层片、锥形束CT均显示牙根突入上颌窦时,曲面体层片测量上颌后牙牙根突入上颌窦距离为(2.19±1.82)mm,而锥形束CT测量距离为(1.47±1.01)mm,两者差异具有统计学意义(P<0.05)。结论曲面体层片判断上颌后牙牙根未进入上颌窦的准确率较高,但判断上颌后牙牙根突入上颌窦的准确率较低。     

应用高频超声建立未育女性腹直肌间距正常值参考范围及影响因素分析

目的 应用高频超声测量未育女性在四个位置的腹直肌间距并分析相关因素,旨在初步制定正常腹直肌间距(IRD)的参考值范围。 方法 选取2019年6月至2019年9月在我院行健康体检的106名健康未育女性志愿者,体质量指数（BMI）均≤30kg/m2,应用高频超声分别于仰卧位静息状态及卷腹动作测量脐上3cm、脐部、脐下2cm和脐下3cm四个位置的IRD,应用百分位数法计算IRD参考值范围,并分析IRD与年龄、身高、体重、BMI指数之间的关系。 结果 未育女性仰卧位静息状态IRD正常值范围如下：脐上3cm为4~15mm,脐部为5~20mm,脐下2cm为0~7mm,脐下3cm为0~3mm。相关性分析显示IRD与年龄、身高无相关性,与体重和BMI指数呈较弱的正相关。 结论 本研究应用高频超声初步建立了未育女性IRD的参考值范围,为腹直肌分离的诊断提供了依据,IRD与体重和BMI指数呈较弱的正相关。     

一测多评法测定心可宁胶囊中6种蟾蜍二烯内酯类化合物

目的 建立一测多评法同时测定心可宁胶囊中6种蟾蜍二烯内酯类化合物的含量,并验证此方法在心可宁胶囊中应用的可行性和准确性。方法 以华蟾酥毒基为内参物,建立日蟾毒它灵、沙蟾毒精、蟾毒它灵、蟾毒灵和脂蟾毒配基与华蟾酥毒基的相对校正因子。分别采用外标法和一测多评法测定心可宁胶囊中6种蟾蜍二烯内酯类化合物的含量,比较2种方法的结果差异,验证一测多评法的可行性和准确性。结果 日蟾毒它灵、沙蟾毒精、蟾毒它灵、蟾毒灵和脂蟾毒配基与华蟾酥毒基的相对校正因子分别为1.06,0.862,0.897,1.09,0.915;2种方法结果无显著差异。结论 以华蟾酥毒基为内参物建立的相对校正因子重现性好,一测多评法可用于心可宁胶囊中多个蟾蜍二烯内酯类成分的质量评价。