Background For esthetic consideration, dentin color post core materials were normally used for all-ceramic crown restorations. However, in some cases, clinicians have to consider combining a full ceramic crown with a ...Background For esthetic consideration, dentin color post core materials were normally used for all-ceramic crown restorations. However, in some cases, clinicians have to consider combining a full ceramic crown with a metal post core. Therefore, this experiment was conducted to test the esthetical possibility of applying cast metal post core in a full ceramic crown restoration.Methods The color of full ceramic crowns on gold and Nickel-Chrome post cores was compared with the color of the same crowns on tooth colored post cores. Different try-in pastes were used to imitate the influence of a composite cementation on the color of different restorative combinations. The majority of patients could not detect any color difference less than △E 1.8 between the two ceramic samples. So, △E 1.8 was taken as the objective evaluative criterion for the evaluation of color matching and patients＇ satisfaction. Results When the Empress 2 crown was combined with the gold alloy post core, the color of the resulting material was similar to that of a glass fiber reinforced resin post core （△E = 0.3）. The gold alloy post core and the try-in paste did not show a perceptible color change in the full ceramic crowns, which indicated that the color of the crowns might not be susceptible to change between lab and clinic as well as during the process of composite cementation. Without an opaque covering the Ni-Cr post core would cause an unacceptable color effect on the crown （△E = 2.0）, but with opaque covering, the color effect became more clinically satisfactory （△E = 1.8）. Conclusions It may be possible to apply a gold alloy post core in the Empress 2 full ceramic crown restoration when necessary. If a non-extractible Ni-Cr post core exists in the root canal, it might be possible to restore the tooth with an Empress 2 crown after covering the labial surface of the core with one layer of opaque resin cement.展开更多
The leaf economic spectrum(LES)quantifes correlations between key leaf traits across vascular plants and distills much of the variation in these traits to a single axis.The LES,remarkable in its near universality,has ...The leaf economic spectrum(LES)quantifes correlations between key leaf traits across vascular plants and distills much of the variation in these traits to a single axis.The LES,remarkable in its near universality,has been extensively researched across a variety of contexts.However,parasitic plants relationship to the LES framework remains relatively unexplored.Because the LES is,in part,driven by physiological tradeoffs in the acquisition of carbon(C),in theory heterotrophy in parasitic plants,which supplants some of the essential functions of leaves,could lead to departures from the LES.Using global leaf trait data from the TRY database,this work assessed the overall representation of parasitic plants in the TRY database,then compared the LES suite of leaf traits in parasitic plants to their non-parasitic counterparts.Despite their unique physiology,parasitic plants did not deviate dramatically from the LES,although there were examples of differences in position on the LES and relationships among traits.Perhaps more importantly,parasitic plants are not well represented in the TRY database,making any conclusions here premature.展开更多
A new sensitive adsorptive voltammetric method was described for the determination of zirconium at a carbon paste electrode (CPE) in the presence of alizarin complexone (ALC). Optimal analytical conditions are: 1.0?0...A new sensitive adsorptive voltammetric method was described for the determination of zirconium at a carbon paste electrode (CPE) in the presence of alizarin complexone (ALC). Optimal analytical conditions are: 1.0?0-6 or 5.0?0-7 mol/L ALC, 0. 20 mol/L HAC-NaAc (pH 4.3), accumulation for 60 s at 0 V (vs. SCE), and linear scanning from 0 V to 1.0 V at 250 mV/s. The peak potential of the complex is at 0.81 V. By using a model JP-303 polarographic analyzer, 2.0?0-10 mol/L (S/N=3) zirconium can be detected with a 90 s accumulation, when the 2nd-order derivative linear sweep technique is used, and the linear range is 6.0?0-10-2.0?0-8 mol/L (5.0?0-7 mol/L ALC) and 2.0?0-8-2.0?0-7 mol/L (1.0?0-6 mol/L ALC), respectively. The developed method was applied to the determination of trace zirconium in the ore samples with satisfactory results.展开更多
本文基于英国国家语料库的统计数据,运用“构式搭配分析法”考察英语中try to V和try V-ing构式的搭配,旨在探究两个构式中try与to V和V-ing的搭配偏好和排斥,以及两个构式中V槽动词的语义聚类特征及其与构式义的关联。研究发现:1)try t...本文基于英国国家语料库的统计数据,运用“构式搭配分析法”考察英语中try to V和try V-ing构式的搭配,旨在探究两个构式中try与to V和V-ing的搭配偏好和排斥,以及两个构式中V槽动词的语义聚类特征及其与构式义的关联。研究发现:1)try to V构式偏好与表示“得到”“使役”“劝阻”等义的V槽动词搭配;排斥与表示“状态”“意愿”义的V槽动词搭配。2)try V-ing构式偏好与表示“使用”“言说”“日常行为”义的V槽动词搭配。3)try to V构式V槽动词的语义聚焦于需要付出较大努力执行和完成的动作;try V-ing构式V槽动词的语义聚焦于使用手、足、耳、眼等器官执行和完成的日常动作。Try to V和try V-ing构式V槽动词的语义聚类体现了两者的构式义。4)V槽动词与try to V和try V-ing构式的搭配是语言使用者凭借语言知识所作的预判和推断,这一搭配特征体现为“相同则吸引,相异则排斥”。以上研究表明,构式搭配分析法为英语try to V和try V-ing构式的搭配研究提供了一个新的视角,对探讨动宾构式宾语和动词搭配具有一定的普遍意义。展开更多
A virtual cosmetics try-on system provides a realistic try-on experience for consumers and helps them efficiently choose suitable cosmetics.In this article,we propose a real-time augmented reality virtual cosmetics tr...A virtual cosmetics try-on system provides a realistic try-on experience for consumers and helps them efficiently choose suitable cosmetics.In this article,we propose a real-time augmented reality virtual cosmetics try-on system for smartphones(ARCosmetics),taking speed,accuracy,and stability into consideration at each step to ensure a better user experience.A novel and very fast face tracking method utilizes the face detection box and the average position of facial landmarks to estimate the faces in continuous frames.A dynamic weight Wing loss is introduced to assign a dynamic weight to every landmark by the estimated error during training.It balances the attention between small,medium,and large range error and thus increases the accuracy and robustness.We also designed a weighted average method to utilize the information of the adjacent frame for landmark refinement,guaranteeing the stability of the generated landmarks.Extensive experiments conducted on a large 106-point facial landmark dataset and the 300-VW dataset demonstrate the superior performance of the proposed method compared to other state-of-the-art methods.We also conducted user satisfaction studies further to verify the efficiency and effectiveness of our ARCosmetics system.展开更多
文摘Background For esthetic consideration, dentin color post core materials were normally used for all-ceramic crown restorations. However, in some cases, clinicians have to consider combining a full ceramic crown with a metal post core. Therefore, this experiment was conducted to test the esthetical possibility of applying cast metal post core in a full ceramic crown restoration.Methods The color of full ceramic crowns on gold and Nickel-Chrome post cores was compared with the color of the same crowns on tooth colored post cores. Different try-in pastes were used to imitate the influence of a composite cementation on the color of different restorative combinations. The majority of patients could not detect any color difference less than △E 1.8 between the two ceramic samples. So, △E 1.8 was taken as the objective evaluative criterion for the evaluation of color matching and patients＇ satisfaction. Results When the Empress 2 crown was combined with the gold alloy post core, the color of the resulting material was similar to that of a glass fiber reinforced resin post core （△E = 0.3）. The gold alloy post core and the try-in paste did not show a perceptible color change in the full ceramic crowns, which indicated that the color of the crowns might not be susceptible to change between lab and clinic as well as during the process of composite cementation. Without an opaque covering the Ni-Cr post core would cause an unacceptable color effect on the crown （△E = 2.0）, but with opaque covering, the color effect became more clinically satisfactory （△E = 1.8）. Conclusions It may be possible to apply a gold alloy post core in the Empress 2 full ceramic crown restoration when necessary. If a non-extractible Ni-Cr post core exists in the root canal, it might be possible to restore the tooth with an Empress 2 crown after covering the labial surface of the core with one layer of opaque resin cement.
基金supported by the Department of Integrative Biology at University of California Berkeley.
文摘The leaf economic spectrum(LES)quantifes correlations between key leaf traits across vascular plants and distills much of the variation in these traits to a single axis.The LES,remarkable in its near universality,has been extensively researched across a variety of contexts.However,parasitic plants relationship to the LES framework remains relatively unexplored.Because the LES is,in part,driven by physiological tradeoffs in the acquisition of carbon(C),in theory heterotrophy in parasitic plants,which supplants some of the essential functions of leaves,could lead to departures from the LES.Using global leaf trait data from the TRY database,this work assessed the overall representation of parasitic plants in the TRY database,then compared the LES suite of leaf traits in parasitic plants to their non-parasitic counterparts.Despite their unique physiology,parasitic plants did not deviate dramatically from the LES,although there were examples of differences in position on the LES and relationships among traits.Perhaps more importantly,parasitic plants are not well represented in the TRY database,making any conclusions here premature.
文摘A new sensitive adsorptive voltammetric method was described for the determination of zirconium at a carbon paste electrode (CPE) in the presence of alizarin complexone (ALC). Optimal analytical conditions are: 1.0?0-6 or 5.0?0-7 mol/L ALC, 0. 20 mol/L HAC-NaAc (pH 4.3), accumulation for 60 s at 0 V (vs. SCE), and linear scanning from 0 V to 1.0 V at 250 mV/s. The peak potential of the complex is at 0.81 V. By using a model JP-303 polarographic analyzer, 2.0?0-10 mol/L (S/N=3) zirconium can be detected with a 90 s accumulation, when the 2nd-order derivative linear sweep technique is used, and the linear range is 6.0?0-10-2.0?0-8 mol/L (5.0?0-7 mol/L ALC) and 2.0?0-8-2.0?0-7 mol/L (1.0?0-6 mol/L ALC), respectively. The developed method was applied to the determination of trace zirconium in the ore samples with satisfactory results.
文摘本文基于英国国家语料库的统计数据,运用“构式搭配分析法”考察英语中try to V和try V-ing构式的搭配,旨在探究两个构式中try与to V和V-ing的搭配偏好和排斥,以及两个构式中V槽动词的语义聚类特征及其与构式义的关联。研究发现:1)try to V构式偏好与表示“得到”“使役”“劝阻”等义的V槽动词搭配;排斥与表示“状态”“意愿”义的V槽动词搭配。2)try V-ing构式偏好与表示“使用”“言说”“日常行为”义的V槽动词搭配。3)try to V构式V槽动词的语义聚焦于需要付出较大努力执行和完成的动作;try V-ing构式V槽动词的语义聚焦于使用手、足、耳、眼等器官执行和完成的日常动作。Try to V和try V-ing构式V槽动词的语义聚类体现了两者的构式义。4)V槽动词与try to V和try V-ing构式的搭配是语言使用者凭借语言知识所作的预判和推断,这一搭配特征体现为“相同则吸引,相异则排斥”。以上研究表明,构式搭配分析法为英语try to V和try V-ing构式的搭配研究提供了一个新的视角,对探讨动宾构式宾语和动词搭配具有一定的普遍意义。
基金supported in part by the National Key R&D Program of China(2021ZD0140407)in part by the National Natural Science Foundation of China(Grant No.U21A20523).
文摘A virtual cosmetics try-on system provides a realistic try-on experience for consumers and helps them efficiently choose suitable cosmetics.In this article,we propose a real-time augmented reality virtual cosmetics try-on system for smartphones(ARCosmetics),taking speed,accuracy,and stability into consideration at each step to ensure a better user experience.A novel and very fast face tracking method utilizes the face detection box and the average position of facial landmarks to estimate the faces in continuous frames.A dynamic weight Wing loss is introduced to assign a dynamic weight to every landmark by the estimated error during training.It balances the attention between small,medium,and large range error and thus increases the accuracy and robustness.We also designed a weighted average method to utilize the information of the adjacent frame for landmark refinement,guaranteeing the stability of the generated landmarks.Extensive experiments conducted on a large 106-point facial landmark dataset and the 300-VW dataset demonstrate the superior performance of the proposed method compared to other state-of-the-art methods.We also conducted user satisfaction studies further to verify the efficiency and effectiveness of our ARCosmetics system.
