Accuracy and reproducibility of 3D digital tooth preparations made by gypsum materials of various colors

Tan, Fa-Bing,Wang, Chao,Dai, Hong-Wei,Fan, Yu-Bo,Song, Jin-Lin The Korean Academy of Prosthodonitics 2018 The Journal of Advanced Prosthodontics Vol.10 No.1

PURPOSE. The study aimed to identify the accuracy and reproducibility of preparations made by gypsum materials of various colors using quantitative and semi-quantitative three-dimensional (3D) approach. MATERIALS AND METHODS. A titanium maxillary first molar preparation was created as reference dataset (REF). Silicone impressions were duplicated from REF and randomized into 6 groups (n=8). Gypsum preparations were formed and grouped according to the color of gypsum materials, and light-scanned to obtain prepared datasets (PRE). Then, in terms of accuracy, PRE were superimposed on REF using the best-fit-algorithm and PRE underwent intragroup pairwise best-fit alignment for assessing reproducibility. Root mean square deviation (RMSD) and degrees of similarity (DS) were computed and analyzed with SPSS 20.0 statistical software (${\alpha}=.05$). RESULTS. In terms of accuracy, PREs in 3D directions were increased in the 6 color groups (from 19.38 to $20.88{\mu}m$), of which the marginal and internal variations ranged $51.36-58.26{\mu}m$ and $18.33-20.04{\mu}m$, respectively. On the other hand, RMSD value and DS-scores did not show significant differences among groups. Regarding reproducibility, both RMSD and DS-scores showed statistically significant differences among groups, while RMSD values of the 6 color groups were less than $5{\mu}m$, of which blue color group was the smallest ($3.27{\pm}0.24{\mu}m$) and white color group was the largest ($4.24{\pm}0.36{\mu}m$). These results were consistent with the DS data. CONCLUSION. The 3D volume of the PREs was predisposed towards an increase during digitalization, which was unaffected by gypsum color. Furthermore, the reproducibility of digitalizing scanning differed negligibly among different gypsum colors, especially in comparison to clinically observed discrepancies.

Effect of different tooth preparation designs on the marginal and internal fit discrepancies of cobalt-chromium crowns produced by computer-aided designing and selective laser melting processes

Na Yu,Hong-Wei Dai,Fa-Bing Tan,Jin-Lin Song,Chao-Yi Ma,Xue-Lu Tong 대한치과보철학회 2021 The Journal of Advanced Prosthodontics Vol.13 No.5

PURPOSE. To evaluate the impact of five different tooth preparation designs on the marginal and internal fit discrepancies of cobalt-chromium (CoCr) crowns produced by computer-aided designing (CAD) and selective laser melting (SLM) processes. MATERIALS AND METHODS. Five preparation data were constructed, after which design crowns were obtained. Actual crowns were fabricated using an SLM process. After the data of actual crowns were obtained with structural light scanning, intaglio surfaces of the design crown and actual crown were virtually superimposed on the preparation. The fit-discrepancies were displayed with colors, while the root means square was calculated and analyzed with one-way analysis of variance (ANOVA), Tukey’s test or Kruskal-Wallis test (α = .05). RESULTS. The marginal or internal color-coded images in the five design groups were not identical. The shoulder-lip and sharp line angle groups in the CAD or SLM process had larger marginal or internal fit discrepancies compared to other groups (P < .05). In the CAD process, the mean marginal and internal fit discrepancies were 10.0 to 24.2 μm and 29.6 to 31.4 μm, respectively. After the CAD and SLM processes, the mean marginal and internal fit discrepancies were 18.4 to 40.9 μm and 39.1 to 47.1 μm, respectively. The SLM process itself resulted in a positive increase of the marginal (6.0 - 16.7 μm) and internal (9.0 - 15.7 μm) fit discrepancies. CONCLUSION. The CAD and SLM processes affected the fit of CoCr crowns and varied based on the preparation designs. Typically, the shoulder-lip and sharp line angle designs had a more significant effect on crown fit. However, the differences between the design groups were relatively small, especially when compared to fit discrepancies observed clinically.

Study of the Enhancement of Magnetic Properties of NdFeB Materials Fabricated by Modified HDDR Process

Meng Fu,Fa-zeng Lian,Ji-jie Wang,Wen-li Pei,Yu-lan Chen,Hong-cai Yang 한국자기학회 2004 Journal of Magnetics Vol.9 No.4

The HDDR (Hydrogenation-Disproportionation-Desorption-Recombination) process is a special method to produce anisotropic NdFeB powders for bonded magnet. The effect of the modified HDDR process on magnetic properties of Nd₂Fe₁₄B-based magnet with several composition Nd_(11.2)Fe_(66.5-x)Co_(15.4)B_(6.8)Zr_(0.1)Ga_x (x = 0~1.0) and that of microelement Ga, disproportional temperature and annealing temperature on jHc, grain size were investigated in order to produce anisotropic powder with high magnetic properties. It was found that modified HDDR process is very effective to enhance magnetic properties and to fine grain size. The addition of Ga could change disproportionation character remarkably of the alloy and could improve magnetic properties of magnet powder. Increasing annealing temperature induces significant grain growth. And grain size produced by modified HDDR process is significantly smaller than those produced by conventional HDDR process.

A Discovery of Low Hydraulic Resistance Channel Along Meridians

Wei-Bo Zhang,Yu-Ying Tian,Hong Li,Jia-He Tian,Ming-Fu Luo,Fa-Liang Xu,Guang-Jun Wang,Tao Huang,Yi-Hui Xu,Rui-Hong Wang 사단법인약침학회 2008 Journal of Acupuncture & Meridian Studies Vol.1 No.1

A hydro-mechanic model was put forward to study the fundamental nature of acupuncture meridians. The basic state of low hydraulic resistance was tested on humans and mini pigs using three methods. The first, a modified Guyton’s method, proved that there was lower hydraulic resistance on meridians compared with nonmeridians. The second scanning method involved a single pressure transducer that can find the lowest resistance point in tissue, and the third method used two transducers and provided a more stable measurement. Using the latter method, low hydraulic resistance points were found very close to low impedance points along meridians. The transmission of artificial interstitial fluid pressure waves was measured to examine their connection to the low resistance points, with the result that a good connection between the points was confirmed. This means the points form channels along the meridians that we refer to as low hydraulic resistance channels. The channel was imaged through isotopic tracing and a migration of isotope 99mTe could be found along the channel. The layer of the channel was detected by injecting Alcian blue and the track was found beneath the skin. All of the above experiments suggest the existence of a new type of channel in living tissues that has not yet been described in modern science, but coincides quite well with the Qi channel theory of traditional Chinese medicine. A hydro-mechanic model was put forward to study the fundamental nature of acupuncture meridians. The basic state of low hydraulic resistance was tested on humans and mini pigs using three methods. The first, a modified Guyton’s method, proved that there was lower hydraulic resistance on meridians compared with nonmeridians. The second scanning method involved a single pressure transducer that can find the lowest resistance point in tissue, and the third method used two transducers and provided a more stable measurement. Using the latter method, low hydraulic resistance points were found very close to low impedance points along meridians. The transmission of artificial interstitial fluid pressure waves was measured to examine their connection to the low resistance points, with the result that a good connection between the points was confirmed. This means the points form channels along the meridians that we refer to as low hydraulic resistance channels. The channel was imaged through isotopic tracing and a migration of isotope 99mTe could be found along the channel. The layer of the channel was detected by injecting Alcian blue and the track was found beneath the skin. All of the above experiments suggest the existence of a new type of channel in living tissues that has not yet been described in modern science, but coincides quite well with the Qi channel theory of traditional Chinese medicine.

Electromagnetic Field Exposure and Male Breast Cancer Risk: A Meta-analysis of 18 Studies

Sun, Jing-Wen,Li, Xiao-Rong,Gao, Hong-Yu,Yin, Jie-Yun,Qin, Qin,Nie, Shao-Fa,Wei, Sheng Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.1

Background: The possibility that electromagnetic fields (EMF) exposure may increase male breast cancer risk has been discussed for a long time. However, arguments have been presented that studies limited by poor quality could have led to statistically significant results by chance or bias. Moreover, data fo the last 10 years have not been systematically summarized. Methods and Results: To confirm any possible association, a meta-analysis was performed by a systematic search strategy. Totals of 7 case-control and 11 cohort studies was identified and pooled ORs with 95% CIs were used as the principal outcome measures. Data from these studies were extracted with a standard meta-analysis procedure and grouped in relation to study design, cut-off point, exposure assessment method, adjustment and exposure model. A statistical significant increased risk of male breast cancer with EMF exposure was defined (pooled ORs = 1.32, 95% CI = 1.14-1.52, P < 0.001), and subgroup analyses also showed similar results. Conclusions: This meta-analysis suggests that EMF exposure may be associated with the increase risk of male breast cancer despite the arguments raised.

Experimental Study on Magnesium Sulfate Cement Concrete Splices of Widened Box Girder

Li-fang Zhang,Jun Yan,Hai-yan Ma,Hong-fa Yu,Ying Wang,Qi-quan Mei 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.12

The connecting part of bridge widening undertakes complicated forces and tends to crack. Basic magnesium sulfate cement concrete has excellent properties such as ideal early strength and tensile strength, meeting the performance requirements of joint materials. Experiments of two spliced box girder specimens with C40 basic magnesium sulfate cement concrete (MC) and normal Portland cement concrete (NC) as joint materials are carried out. Concrete strain, reinforcement strain, deflection and crack propagation law of the joint section are tested and analyzed under symmetrical loading at the cantilever of the box girders. The study shows when MC material is used in the splicing section, the joint section showed a multi-cracks failure mode with an ultimate load ratio of 0.99 and a maximum crack width of 1.3 mm; NC joint section has only three longitudinal cracks with an ultimate load ratio of 0.97 and a maximum crack width of 0.98 mm. Under the same load, the crack width and the deflection of mid-span MC joint section are greater than which of NC joint section. The maximum deflection of NC splicing section is 1.20 mm, which is 1/633 of the calculating span length. The maximum deflection of MC spliced section is 2.03 mm, which is 1/374 of the calculating span length. Comparison of the maximum deflection and the maximum crack width shows that MC material has better ductility.

Diversity of Arbuscular Mycorrhizal Fungi Associated with a Sb Accumulator Plant, Ramie (Boehmeria nivea), in an Active Sb Mining

( Yuan Wei ),( Zhi Peng Chen ),( Feng Chang Wu ),( Ji Ning Li ),( Yu Xian Shangguan ),( Fa Sheng Li ),( Qing Ru Zeng ),( Hong Hou ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.8

Arbuscular mycorrhizal fungi (AMF) have great potential for assisting heavy metal hyperaccumulators in the remediation of contaminated soils. However, little information is available about the symbiosis of AMF associated with an antimony (Sb) accumulator plant under natural conditions. Therefore, the objective of this study was to investigate the colonization and molecular diversity of AMF associated with the Sb accumulator ramie (Boehmeria nivea) growing in Sb-contaminated soils. Four Sb mine spoils and one adjacent reference area were selected from Xikuangshan in southern China. PCR-DGGE was used to analyze the AMF community composition in ramie roots. Morphological identification was also used to analyze the species in the rhizosphere soil of ramie. Results obtained showed that mycorrhizal symbiosis was established successfully even in the most heavily polluted sites. From the unpolluted site Ref to the highest polluted site T4, the spore numbers and AMF diversity increased at first and then decreased. Colonization increased consistently with the increasing Sb concentrations in the soil. A total of 14 species were identified by morphological analysis. From the total number of species, 4 (29%) belonged to Glomus, 2 (14%) belonged to Acaulospora, 2 (14%) belonged to Funneliformis, 1 (7%) belonged to Claroideoglomus, 1 (7%) belonged to Gigaspora, 1 (7%) belonged to Paraglomus, 1 (7%) belonging to Rhizophagus, 1 (7%) belonging to Sclervocystis, and 1 (7%) belonged to Scutellospora. Some AMF sequences were present even in the most polluted site. Morphological identification and phylogenetic analysis both revealed that most species were affiliated with Glomus, suggesting that Glomus was the dominant genus in this AMF community. This study demonstrated that ramie associated with AMF may have great potential for remediation of Sb-contaminated soils.

Suppression of MED19 expression by shRNA induces inhibition of cell proliferation and tumorigenesis in human prostate cancer cells

( Xin Gang Cui ),( Dan Feng Xu ),( Chao Lv ),( Fa Jun Qu ),( Jin He ),( Ming Chen ),( Yu Shan Liu ),( Yi Gao ),( Jian Ping Che ),( Ya Cheng Yao ),( Hong Yu Yu ) 생화학분자생물학회(구 한국생화학분자생물학회) 2011 BMB Reports Vol.44 No.8

MED19 is a member of the Mediator that plays a key role in the activation and repression of signal transduction or the regulation of transcription in carcinomas. To tested the functional role of MED19 in human prostate cancer, we downregulated MED19 expression in prostate cancer cells (PC-3 and DU145) by lentivirus- mediated short hairpin (shRNA), and analyzed the effect of inhibition of MED19 on prostate cancer cell proliferation and tumorigenesis. The in vitro prostate cancer cell proliferation, colony formation, and in vivo tumor growth in nude mice xenografts was significantly reduced after the downregulation of MED19. Knock- down of MED19 caused S-phase arrest and induced apoptosis via modulation of Bid and Caspase 7. It was suggested that MED19 serves as a novel proliferation regulator that promotes growth of prostate cancer cells. [BMB reports 2011; 44(8): 547-552]