Effect of a Multiple Reduction Die on the Residual Stress of Drawn Materials

Residual stress may influence the mechanical behavior and durability of drawn materials. Thus, this study develops a multiple reduction die (MRD) that can reduce residual stress during the drawing process. The MRD set consists of several die tips, die cases, and lubricating equipment. All the die tips of the MRD were disposed of simultaneously. Finite element analysis of the drawing process was performed according to the reduction ratio of each die tip, and the variables in drawing process with the MRD were optimized using a deep neural network to minimize the residual stress. Experiments on the drawing process with the conventional die and MRD were performed to evaluate the residual stress and verify the effectiveness of the MRD. The results of X-ray diffraction measurements indicated that the axial and hoop residual stresses on the surface were dramatically reduced.     

Antibacterial Effect of Amino Acid–Silver Complex Loaded Montmorillonite Incorporated in Dental Acrylic Resin

Several dental materials contain silver for antibacterial effect, however the effect is relatively low. The reason for the lower antibacterial efficacy of silver is considered to be the fact that silver ions bind to chloride ions in saliva. To develop new effective silver antibacterial agents that can be useful in the mouth, we synthesized two novel amino acid (methionine or histidine)–silver complexes (Met or His–Ag) loaded with montmorillonite (Mont) and analyzed their antibacterial efficacy. At first the complexes were characterized using nuclear magnetic resonance (NMR), and amino acid–Ag complex-loaded Mont (amino acid–Ag–Mont) were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The antibacterial efficacy of these materials in dental acrylic resin was then investigated by bacterial growth measurement using a spectrophotometer. As controls, commercially available silver-loaded zeolite and silver-zirconium phosphate were also tested. Dental acrylic resin incorporating His–Ag–Mont strongly inhibited Streptococcus mutans growth. This was explained by the fact that His-Ag complex revealed the highest amounts of silver ions in the presence of chloride. The structure of the amino acid–Ag complexes affected the silver ion presence in chloride and the antibacterial efficacy. His–Ag–Mont might be used as antibacterial agents for dental materials.     

The Impact of Water and Road Salt with Anti-Caking Agent on the Stiffness of Select Mixes Used for the Road Surface

An original experimental method was used to investigate the influence of water and road salt with anti-caking agent on the material used in pavement construction layers. This method allowed for monitoring material changes resulting from the influence of water and road salt with anti-caking agent over time. The experiment used five different mineral road mixes, which were soaked separately in water and brine for two time intervals (2 days and 21 days). Then, each sample of the mix was subjected to tests of the complex module using the four-point bending (4PB-PR) method. The increase in mass of the soaked samples and the change in value of the stiffness modulus were analyzed. Exemplary tomographic (X-ray) imaging was performed to confirm the reaction of the road salt and anti-caking agent (lead agent) with the material. Based on measurements of the stiffness modulus and absorption, the correlations of the mass change and the value of the stiffness modulus were determined, which may be useful in estimating the sensitivity of mixes to the use of winter maintenance agents—e.g., road salt with anti-caking agent (sodium chloride). It was found that the greatest changes occur for mixes intended for base course layers (mineral cement mix with foamed asphalt (MCAS) and mineral-cement-emulsion mixes (MCE)) and that the smallest changes occur for mixes containing highly modified asphalt (HIMA).     

Tunable Pseudo-Piezoelectric Effect in Doped Calcium Titanate for Bone Tissue Engineering

CaTiO₃ is a promising candidate as a pseudo-piezoelectric scaffold material for bone implantation. In this study, pure and magnesium/iron doped CaTiO₃ are synthesized by sol-gel method and spark plasma sintering. Energy dispersive X-ray mapping confirm the homogenous distribution of doping elements in sintered samples. High-energy X-ray diffraction investigations reveal that doping of nanostructured CaTiO₃ increased the strain and defects in the structure of CaTiO₃ compared to the pure one. This led to a stronger pseudo-piezoelectric effect in the doped samples. The charge produced in magnesium doped CaTiO₃ due to the direct piezoelectric effect is (2.9 ± 0.1) pC which was larger than the one produced in pure CaTiO₃ (2.1 ± 0.3) pC, whereas the maximum charge was generated by iron doped CaTiO₃ with (3.6 ± 0.2) pC. Therefore, the pseudo-piezoelectric behavior can be tuned by doping. This tuning of pseudo-piezoelectric response provides the possibility to systematically study the bone response using different piezoelectric strengths and possibly adjust for bone tissue engineering.     

一站式CT能谱灌注成像预测兔腋窝淋巴结性质

目的 探讨一站式CT能谱灌注成像定量参数预测兔腋窝淋巴结性质的应用价值。方法 将60只新西兰纯种雌性大白兔随机分为2组,分别建立兔乳腺癌腋窝转移性淋巴结（转移组）与炎性淋巴结动物模型（炎症组）。于建模后第4周末对实验兔行一站式CT能谱灌注成像扫描,扫描完成后摘取腋窝淋巴结行病理检查,并与CT图像逐一对照。采用两独立样本t检验比较2组能谱参数和灌注参数的差异,以Logistic回归和ROC曲线分析单一参数和联合参数诊断实验兔腋窝淋巴结性质的效能。结果 转移组淋巴结的血流量（BF）、血容量（BV）、动静脉期碘浓度（IC）、标准化碘基值（NIC）和40~70 keV间的能谱曲线斜率（λ）均高于炎症组（P均<0.05）,平均通过时间（MTT）和表面通透性（PS）差异无统计学意义（P均>0.05）。最佳联合参数（BF+动脉期λ+静脉期λ）的AUC为0.942,以0.65为临界值,其诊断实验兔腋窝乳腺癌转移性淋巴结的敏感度、特异度、阳性预测值和阴性预测值分别为79.68%、95.92%、92.91%和82.70%。结论 一站式CT能谱灌注成像定量参数鉴别兔腋窝乳腺癌转移性淋巴结与炎性淋巴结的诊断效能较好,联合参数（BF+动脉期λ+静脉期λ）具有较高诊断价值。     

特发性间质性肺炎患者18F-FDG PET/CT与肺功能及炎性指标的相关性

目的 观察特发性间质性肺炎（ⅡP）患者¹⁸F-FDG PET/CT显像与肺功能及实验室炎性指标的关系。方法 回顾性分析20例ⅡP患者（ⅡP组）和20例肺部正常患者（对照组）的PET/CT图像,测量全肺最大标准摄取值（SUV_max）和平均标准摄取值（SUV_mean）,并校正获得最大靶背景比（TBR_max）和平均靶背景比（TBR_mean）,比较ⅡP组与对照组间SUV和TBR的差异,评价ⅡP组TBR与肺功能及炎性指标的相关性。结果 ⅡP组SUV_max、SUV_mean、TBR_max和TBR_mean均显著高于对照组（P均<0.001）。ⅡP组TBR_mean与用力肺活量（FVC,r=-0.811,P=0.004）、肺一氧化碳弥散量（DLCO,r=-0.715,P=0.020）、第1秒用力呼气量（FEV1,r=-0.698,P=0.025）、残气量（RV,r=-0.844,P=0.002）、肺总量（TLC,r=-0.693,P=0.026）及RV/TLC（r=-0.711,P=0.021）呈负相关,与FEV1/FVC（r=0.888,P=0.001）呈正相关。TBR_max与FVC（r=-0.667,P=0.035）和RV（r=-0.643,P=0.045）呈负相关,与DLCO、FEV1、FEV1/FVC、TLC、RV/TLC无明显相关性（P均>0.05）。ⅡP组TBR_max和TBR_mean分别与红细胞沉降率、C反应蛋白均无明显相关性（P均>0.05）。结论 ⅡP患者¹⁸F-FDG放射性摄取增高,其程度与肺功能具有一定相关性。     

基于超声-CT图像的心脏影像融合数据处理方法

目的 应用多模态心脏影像融合技术进行动物实验,获取超声-CT心脏影像融合方法和检验指标,并通过临床试验验证其可行性。方法 采集6只比格犬心脏CT增强图像和超声心脏瓣膜容积图像,使用Mimics innovationsuite 19.0及3-Matic 11.0软件将各配准点及瓣环平面对齐,将超声心脏瓣膜图像融合至CT心脏腔室上,于融合图像和心脏标本中测量配准指标：二尖瓣前外侧联合点（ALC）、后内侧联合点（PIC）、主动脉瓣闭合口（AVC）到心尖部的最大径（D-ALC、D-PIC、D-AVC）及二尖瓣环平面与主动脉瓣环平面夹角（AMA）。对41例心房颤动患者行CT和经食管超声检查,采用同样方法处理图像,并测量基于CT图像和基于CT-超声融合图像的配准指标。结果 动物实验中,超声-CT心脏影像融合成功,融合图像与心脏标本中测量D-ALC、D-PIC、D-AVC和AMA差异均无统计学意义（P均>0.05）。对41例患者均成功完成超声-CT心脏影像融合配准,临床融合组与临床CT组间D-ALC、D-PIC、D-AVC和AMA测量值差异均无统计学意义（P均>0.05）。图像融合后AMA差值在5°以内者占92.68%（38/41）,D-ALC、D-PIC、D-AVC差值百分比均在5%以内者占87.80%（36/41）。结论 采用以瓣环为解剖定位标志的内部特征法进行心脏CT-超声影像融合可行且准确;AMA和瓣环平面与心尖部距离差值可作为检测配准准确性的指标。     

人工智能骨龄评测系统评估儿童腕骨骨龄

目的 探讨人工智能（AI）系统评测儿童腕骨骨龄的可行性。方法 回顾性分析130幅1~13岁儿童左手骨龄X线片。以3名中高年资放射科医师腕骨骨龄评测结果为参考标准,计算并对比AI系统（简称模型）及3名低年资放射科医师（医师1、2、3,简称医师）与参考标准之间腕骨骨龄和腕骨成熟度分值的均方根误差（RMSE）及平均绝对误差（MAE）;采用组内相关系数（ICC）评价模型、医师与参考标准之间评测骨龄结果的一致性;比较模型与医师间骨龄测评时间。结果 模型与参考标准之间腕骨骨龄的MAE、RMSE与医师1、2与参考标准之间MAE、RMSE差异均有统计学意义（P均<0.05）,与医师3的MAE、RMSE差异无统计学意义（P均>0.05）。模型与参考标准之间腕骨成熟度分值的MAE、RMSE与医师1、参考标准之间MAE、RMSE差异均有统计学意义（P均<0.05）,与医师2、3的MAE、RMSE差异均无统计学意义（P均>0.05）。模型与参考标准之间腕骨骨龄评测结果的ICC=0.997,医师1、2、3与参考标准之间ICC分别为0.994、0.996、0.997。模型对骨龄的测评时间均小于医师（P均<0.001）。结论 AI骨龄评测系统能够准确、快速评估儿童腕骨骨龄。     

定量CT测量T12骨密度替代病变腰椎用于骨质疏松诊断的可行性

目的 探讨在低剂量CT肺癌筛查联合定量CT骨密度检查中,以测量T12椎体骨密度替代病变的L1或L2用于骨质疏松诊断的可行性。方法 选取1 298名接受低剂量CT肺癌筛查联合定量CT骨密度检查的健康体检者,测量其T12、L1、L2椎体骨密度,并计算校准的T12骨密度,记为T12^*。以L1+L2为诊断标准,分别分析各椎体组合T12+L1、T12+L2、T12^*+L1、T12^*+L2与L1+L2评估骨量的一致性和诊断骨质疏松的差异性。结果 各椎体组合与L1+L2评估骨量的一致性均较好（Kappa均>0.75,P均<0.05）。各椎体组合诊断骨质疏松的特异度均>98%。T12+L1、T12+L2诊断骨质疏松的敏感度分别为73.33%（143/195）及77.95%（152/195）;而T12^*+L1、T12^*+L2诊断骨质疏松的敏感度分别为83.08%（162/195）及90.26%（176/195）。结论 定量CT测量T12骨密度替代病变L1或L2,可能降低诊断骨质疏松的敏感度,应对其进行校准。     

基于增强CT影像组学模型鉴别肾透明细胞癌与非透明细胞癌

目的 建立基于增强CT的影像组学模型,评估其鉴别肾透明细胞癌（ccRCC）与非透明细胞癌（non-ccRCC）的应用价值。方法 将147例ccRCC及32例non-ccRCC患者随机分为训练集125例和测试集54例。将所有患者的增强CT资料导入ITK-SNAP软件,手动勾画ROI,获得16个特征,分别建立基于特征的随机森林（RF）模型和逻辑回归（LR）模型,采用ROC曲线观察模型对ccRCC的诊断效能。结果 训练集RF模型诊断ccRCC的AUC为0.96（P<0.05）,特异度为1.00,敏感度0.83;LR模型诊断ccRCC的AUC为0.96（P<0.05）,特异度为1.00,敏感度为0.83。测试集RF模型诊断ccRCC的AUC为0.96（P<0.05）,特异度为1.00,敏感度为0.89;LR模型诊断ccRCC的AUC为0.88（P<0.05）,特异度为0.90,敏感度为0.77。结论 基于增强CT影像组学模型可用于鉴别ccRCC与non-ccRCC;RF模型诊断价值较LR模型更高。