Wear of 3D printed and CAD/CAM milled interim resin materials after chewing simulation

Gerelmaa Myagmar,Jae-Hyun Lee,Jin-Soo Ahn,In-Sung Luke Yeo,Hyung-In Yoon,Jung-Suk Han 대한치과보철학회 2021 The Journal of Advanced Prosthodontics Vol.13 No.3

PURPOSE. The purpose of this in vitro study was to investigate the wear resistance and surface roughness of three interim resin materials, which were subjected to chewing simulation. MATERIALS AND METHODS. Three interim resin materials were evaluated: (1) three-dimensional (3D) printed (digital light processing type), (2) computer-aided design and computer-aided manufacturing (CAD/CAM) milled, and (3) conventional polymethyl methacrylate interim resin materials. A total of 48 substrate specimens were prepared. The specimens were divided into two subgroups and subjected to 30,000 or 60,000 cycles of chewing simulation (n = 8). The wear volume loss and surface roughness of the materials were compared. Statistical analysis was performed using oneway analysis of variance and Tukey’s post-hoc test (α=.05). RESULTS. The mean ± standard deviation values of wear volume loss (in mm3) against the metal abrader after 60,000 cycles were 0.10 ± 0.01 for the 3D printed resin, 0.21 ± 0.02 for the milled resin, and 0.44 ± 0.01 for the conventional resin. Statistically significant differences among volume losses were found in the order of 3D printed, milled, and conventional interim materials (P <.001). After 60,000 cycles of simulated chewing, the mean surface roughness (Ra; μm) values for 3D printed, milled, and conventional materials were 0.59 ± 0.06, 1.27 ± 0.49, and 1.64 ± 0.44, respectively. A significant difference was found in the Ra value between 3D printed and conventional materials (P =.01). CONCLUSION. The interim restorative materials for additive and subtractive manufacturing digital technologies exhibited less wear volume loss than the conventional interim resin. The 3D printed interim restorative material showed a smoother surface than the conventional interim material after simulated chewing.

Classification of Crop Lands over Northern Mongolia Using Multi-Temporal Landsat TM Data

( Gerelmaa Ganbaatar ),( Kyu Sung Lee ) 대한원격탐사학회 2013 大韓遠隔探査學會誌 Vol.29 No.6

Although the need of crop production has increased in Mongolia, crop cultivation is very limited because of the harsh climatic and topographic conditions. Crop lands are sparsely distributed with relatively small sizes and, therefore, it is difficult to survey the exact area of crop lands. The study aimed to find an easy and effective way of accurate classification to map crop lands in Mongolia using satellite images. To classify the crop lands over the study area in northern Mongolia, four classifications were carried out by using 1) Thematic Mapper (TM) image August 23, 2) TM image of July 6, 3) combined 12 bands of TM images of July and August, and 4) both TM images of July and August by layered classification. Wheat and potato are the major crop types and they show relatively high variation in crop conditions between July and August. On the other hands, other land cover types (forest, riparian vegetation, grassland, water and bare soil) do not show such difference between July and August. The results of four classifications clearly show that the use of multi-temporal images is essential to accurately classify the crop lands. The layered classification method, in which each class is separated by a subset of TM images, shows the highest classification accuracy (93.7%) of the crop lands. The classification accuracies are lower when we use only a single TM image of either July or August. Because of the different planting practice of potato and the growth condition of wheat, the spectral characteristics of potato and wheat cannot be fully separated from other cover types with TM image of either July or August. Further refinements on the spatial characteristics of existing crop lands may enhance the crop mapping method in Mongolia.

A Study on Antecedents Affecting Customer Satisfactionin Mongolian Postal Service Sector

Battumur Gerelmaa,김원종,GANTUMURKHONGORZUL 한국인터넷전자상거래학회 2020 인터넷전자상거래연구 Vol.20 No.5

‘Mongol Post’, which owns the main postal network of Mongolia, operates more than 30 types of postal services with more than 900 employees and 38 postal service branches in Ulaanbaatar. The purposes of this study are firstly to investigate how service quality affects satisfaction of those who experience services of Mongol Post, and accordingly to figure out how it directly affect customers’ loyalty. To identify how service quality affect customer satisfaction, the construct of service quality has been divided into seven components including tangibility, reliability, responsiveness, empathy, accessibility, communication, and complaint handling. As this study was conducted with the purpose of measuring customer satisfaction in Mongolian postal service, the research method used in this work is a quantitative method with data collection through questionnaires collected from 298 respondents who have experienced Mongolian postal delivery service. The results of the study show that three of seven components of service quality construct, including reliability, accessibility, and complaint handling of service, have positively influenced customer satisfaction, while the rest four components including tangibility, responsiveness, empathy, and communication, however, have not shown significant effects on customer satisfaction. And the results also show that the customer satisfaction has a positive effect on customers’ loyalty.

Investigating Website Quality in e-Delivery Service in Mongolia to Validate Delone and McLean’s Approach

Battumur Gerelmaa,김원종 한국인터넷전자상거래학회 2022 인터넷전자상거래연구 Vol.22 No.2

Delivery services are a highly competitive field under e-commerce pressure. This paper used Delone and McLean's information system success model to evaluate the impact of e-service quality and e-trust on the e-reuse intention of web site-based delivery services in Mongolia. The Mongolian postal services have changed their policies, resulting in a change in competition and monopoly. The rapid development of the Mongolian Delivery service sector has introduced a competitive environment to competitive services and provided new ideas for express service to understand the customer. Two hundred and ninety-nine customers with experience were surveyed and data was collected with the help of the SPSS 21.0 and AMOS 20.0 statistical packages. In this study, four components of e-service quality constructs (including accessibility, interactivity, ease of use and responsiveness) of e-delivery service have been found to have influenced e-trust, but usefulness has no significant effect on e-trust. Moreover, accessibility and responsiveness (both elements of e-service quality) have been proven to affect e-satisfaction, although ease of use, usefulness, and interaction do not. E-trust has a strong influence on perceived fulfillment and e-reuse expectations. E-satisfaction and e-reuse intention both have a strong effect on E-WOM.

Classification of Crop Lands over Northern Mongolia Using Multi-Temporal Landsat TM Data

Ganbaatar, Gerelmaa,Lee, Kyu-Sung The Korean Society of Remote Sensing 2013 大韓遠隔探査學會誌 Vol.29 No.6

Although the need of crop production has increased in Mongolia, crop cultivation is very limited because of the harsh climatic and topographic conditions. Crop lands are sparsely distributed with relatively small sizes and, therefore, it is difficult to survey the exact area of crop lands. The study aimed to find an easy and effective way of accurate classification to map crop lands in Mongolia using satellite images. To classify the crop lands over the study area in northern Mongolia, four classifications were carried out by using 1) Thematic Mapper (TM) image August 23, 2) TM image of July 6, 3) combined 12 bands of TM images of July and August, and 4) both TM images of July and August by layered classification. Wheat and potato are the major crop types and they show relatively high variation in crop conditions between July and August. On the other hands, other land cover types (forest, riparian vegetation, grassland, water and bare soil) do not show such difference between July and August. The results of four classifications clearly show that the use of multi-temporal images is essential to accurately classify the crop lands. The layered classification method, in which each class is separated by a subset of TM images, shows the highest classification accuracy (93.7%) of the crop lands. The classification accuracies are lower when we use only a single TM image of either July or August. Because of the different planting practice of potato and the growth condition of wheat, the spectral characteristics of potato and wheat cannot be fully separated from other cover types with TM image of either July or August. Further refinements on the spatial characteristics of existing crop lands may enhance the crop mapping method in Mongolia.

The Chronic and Acute Toxicity of Traditional Medicines Containing Terminalia chebula

ARONGQIQIGE,Enebish Gerelmaa,Song Wang,Xi Wei Cheng,Gantumur Anuujin,Altanbayar Oyunbaatar,Shimomura Hirofumi,Chimeddorj Battogtokh,Chuluun Batnairamdal,Amgalanbaatar Avarzed 대한약침학회 2023 Journal of pharmacopuncture Vol.26 No.1

Objectives: Terminalia chebula, the main ingredient of Altan Arur 5, has been used for many years in traditional medicine. This medicine is more effective than other drugs and is used to treat chronic gastritis and gastrointestinal disorders such as peptic ulcers and esophageal reflux. Other ingredients of Altan Arur 5 are Punica granatum (pomegranate), tulip seeds, black balm, and excreta of Trogopterus xanthipes. The main ingredients of T. chebula are antibacterial and analgesic in traditional medicine. Despite having been used for many years and although many studies have been conducted on the beneficial effects of this medicine and its ingredients, the toxicity of Altan Arur 5 has not yet been elucidated. Therefore, we aimed to study the toxicity of Altan Arur 5 to ensure that it is safe to use. Methods: Acute and chronic toxicity of Altan Arur 5 were assessed in 10 Kunming mice and 8 Sprague-Dawley rats, respectively, in different doses. In the acute toxicity study, Altan Arur 5 was orally administered to Kunming mice in doses of 12 g/kg, 24 g/kg, and 48 g/kg for 14 days. In the chronic toxicity study, it was orally administered to Sprague-Dawley rats in doses of 1.25 g/kg, 2.5 g/kg, and 5 g/kg for 12 weeks. Results: No significant differences were observed in the relative organ weights for mice treated with Altan Arur 5 compared with those in the control group. Furthermore, no macro- or microstructural changes were noted in the organs of any group. Conclusion: Our toxicity testing revealed that the traditional medicine Altan Arur 5 has no toxic effects in vivo.

Post Ictal Fractures in a Patient with Parathyroidectomy

Adiyakhuu Otgonbayar,Ankhbayar Erdenebaatar,Narangoo Tsog,Gerelmaa Jargalsaikhan,Onon Ganbold,Oyun-Erdene Choijilsuren,Seulgi Hyeon 대한외과학회 2022 대한외과학회 학술대회 초록집 Vol.2022 No.11

Comparison of the Osteogenic Potential of Titanium and Modified Zirconia-Based Bioceramics

Cho, Young-Dan,Shin, Ji-Cheol,Kim, Hye-Lee,Gerelmaa, Myagmar,Yoon, Hyung-In,Ryoo, Hyun-Mo,Kim, Dae-Joon,Han, Jung-Suk Molecular Diversity Preservation International (MD 2014 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.15 No.3

<P>Zirconia is now favored over titanium for use in dental implant materials because of its superior aesthetic qualities. However, zirconia is susceptible to degradation at lower temperatures. In order to address this issue, we have developed modified zirconia implants that contain tantalum oxide or niobium oxide. Cells attached as efficiently to the zirconia implants as to titanium-based materials, irrespective of surface roughness. Cell proliferation on the polished surface was higher than that on the rough surfaces, but the converse was true for the osteogenic response. Cells on yttrium oxide (Y<SUB>2</SUB>O<SUB>3</SUB>)/tantalum oxide (Ta<SUB>2</SUB>O<SUB>5</SUB>)- and yttrium oxide (Y<SUB>2</SUB>O<SUB>3</SUB>)/niobium oxide (Nb<SUB>2</SUB>O<SUB>5</SUB>)-containing tetragonal zirconia polycrystals (TZP) discs ((Y, Ta)-TZP and (Y, Nb)-TZP, respectively) had a similar proliferative potential as those grown on anodized titanium. The osteogenic potential of MC3T3-E1 pre-osteoblast cells on (Y, Ta)-TZP and (Y, Nb)-TZP was similar to that of cells grown on rough-surface titanium. These data demonstrate that improved zirconia implants, which are resistant to temperature-induced degradation, retain the desirable clinical properties of structural stability and support of an osteogenic response.</P>

Diagnosis and molecular epidemiological study with serotype O and Asia 1 specific primers of foot-and-mouth disease for the field samples from Asia

Kwang Nyeong Lee,Su Mi Kim,Seo Yong Lee,Dashzveg Bold,Ulziibat Gerelmaa,Nguyen Tung,Young Joon Ko,Hyang Sim Lee,Eun Jeong Heo,Chang Hee Kweon,Jong Hyeon Park 대한수의학회 2008 대한수의학회 학술대회발표집 Vol.2008 No.-

Use of a Baculovirus-Expressed Structural Protein for the Detection of Antibodies to Foot-and-Mouth Disease Virus Type A by a Blocking Enzyme-Linked Immunosorbent Assay

Ko, Young-Joon,Lee, Hyang-Sim,Jeoung, Hye-Young,Heo, Eun-Jeong,Ko, Hyo-Rim,Chang, Byung-Sik,Joo, Hoo-Don,Gerelmaa, U.,Dashzeveg, B.,Tserendorj, S.,Sodnomdarjaa, R.,Park, Jong-Hyeon,Kweon, Chang-Hee,Ch American Society for Microbiology 2010 CLINICAL AND VACCINE IMMUNOLOGY Vol.17 No.1

<B>ABSTRACT</B><P>A blocking enzyme-linked immunosorbent assay (ELISA) with a baculovirus-expressed structural protein was developed for the detection of antibodies to foot-and-mouth disease virus type A. It exhibited 99% specificity with a cutoff of 53% inhibition. Its sensitivity was comparable to the sensitivities of the virus neutralization test and the liquid-phase blocking ELISA, indicating its potential as an alternative assay.</P>