• Clinical and Experimental Pediatrics
• /
• v.65 no.5
• /
• pp.254-261
• /
• 2022

Background: The use of systemic steroids for 6+ weeks in children is associated with decreased bone mineral content (BMC) and density (BMD). However, the effects of a shorter duration of use on BMD are unknown. Purpose: To determine the effect of the use of systemic steroids for 2-6 weeks on BMD and BMC in pediatric patients. Methods: Twenty-five pediatric patients (21 with tuberculosis, 2 with systemic juvenile idiopathic arthritis, 1 with inflammatory bowel disease, 1 with autoimmune hemolytic anemia) who received systemic steroids for 2-6 weeks and 25 age- and sex-matched controls were enrolled. BMC, BMD, and z scores of the whole body (WB), lumbar spine (LS), nondominant distal radius (DR), and total body less the head (TBLH) were determined by dual-energy x-ray absorptiometry at baseline, the end of steroid therapy or 6 weeks (whichever was earlier; first follow-up), and at the end of 3 months from baseline (second follow-up) in patients and at baseline in controls. The values were adjusted for confounding variables. Continuous and categorical variables were compared using Student t test and the chi-square test or Fisher exact test, respectively. Pairwise comparisons employed Bonferroni correction. Results: Statistically significant decreases in BMC, BMD, and all z scores were observed. BMC declined by 5.37%, 2.08%, 1.82%, and 2.27%, and 11.42%, 3.75%, 3.34%, and 4.17% for WB, LS, DR, and TBLH, respectively, at the first and second follow-ups, respectively. Similarly, BMD declined by 2.01%, 2.31%, 2.18%, and 1.70% and 4.59%, 3.76%, 3.14%, and 3.50% for the WB, LS, DR, and TBLH, respectively, at the first and second follow-ups, respectively. A significant negative correlation was found among bone densitometric parameters, duration, and cumulative dose. Conclusion: The use of systemic steroids for 2-6 weeks in pediatric patients decreased the BMD and BMC of trabecular and cortical bones, an effect that persisted after discontinuation.

• Journal of the Korea Society for Simulation
• /
• v.19 no.1
• /
• pp.133-141
• /
• 2010

This research suggests a unified scheme for using stratified sampling and control variates method to improve the efficiency of estimation for parameters in simulation experiments. We utilize standardized concomitant variables defined during the course of simulation runs. We first use these concomitant variables to counteract the unknown error of response by the method of control variates, then use a concomitant variable not used in the controlled response and stratify the response into appropriate strata to reduce the variation of controlled response additionally. In case that the covariance between the response and a set of control variates is known, we identify the simulation efficiency of suggested method using control variates and stratified sampling. We conjecture the simulation efficiency of this method is better than that achieved by separated application of either control variates or stratified sampling in a simulation experiments. We investigate such an efficiency gain through simulation on a selected model.

• Analytical Science and Technology
• /
• v.36 no.4
• /
• pp.180-190
• /
• 2023

The presence of process related impurities in any drug or the drug product was associated with its safety, stability and efficacy. The overall literature survey proved that there is no method published on the assessment of process related impurities in brigatinib. In this study, a simple, reliable and stable HPLC qualitative method was reported for quantification of process related impurities with easy and quick extraction procedure. The impurities along with standard brigatinib was resolved on Lichrospher^® C18 (250 mm × 4.6 mm; 5 ㎛ particle size) column in room temperature using methanol, acetonitrile, pH 4.5 phosphate buffer in 55:25:20 (v/v) at 1.0 mL/min as mobile phase and UV detection at 261 nm. The method produces well resolved peaks at retention time of 4.60 min, 12.28 min, 3.37 min, 7.34 min and 8.39 min respectively for brigatinib, impurity A, B, C and D. The method produces a very sensitive detection limit of 0.0065 ㎍/mL, 0.0068 ㎍/mL, 0.0053 ㎍/mL and 0.0058 ㎍/mL for impurity A, B, C and D respectively with calibration curve linear in the concentration range of 22.5-135 ㎍/mL for brigatinib and 0.0225-0.135 ㎍/mL for impurities. The method produces all the validation parameters under the acceptable level and doesn't produces any considerable changes in peak area response while minor changes in the developed method conditions. The method can effectively resolve the unknown stress degradation products along with known impurities with less % degradation. The method can efficiently resolve and quantify the impurities in formulation and hence can suitable for the routine quality analysis of brigatinib in raw material and formulation.

• Journal of the Korea Society for Simulation
• /
• v.32 no.1
• /
• pp.13-21
• /
• 2023

This paper proposes a method of automatically generating a model through a machine learning technique by setting a hypothetical model in the form of a gray box or black box with unknown parameters, when the big data of the actual system is given. We implements the proposed framework and conducts experiments to find an appropriate model among various hypothesis models and compares the cost and fitness of them. As a result we find that the proposed framework works well with continuous systems that could be modeled with ordinary differential equation. This technique is expected to be used well for the purpose of automatically updating the consistency of the digital twin model or predicting the output for new inputs using recently generated big data.

• The korean journal of orthodontics
• /
• v.53 no.3
• /
• pp.194-204
• /
• 2023

Objective: To investigate sex-specific correlations between the dimensions of permanent canines and the anterior Bolton ratio and to construct a statistical model capable of identifying the sex of an unknown subject. Methods: Odontometric data were collected from 121 plaster study models derived from Caucasian orthodontic patients aged 12-17 years at the pretreatment stage by measuring the dimensions of the permanent canines and Bolton's anterior ratio. Sixteen variables were collected for each subject: 12 dimensions of the permanent canines, sex, age, anterior Bolton ratio, and Angle's classification. Data were analyzed using inferential statistics, principal component analysis, and artificial neural network modeling. Results: Sex-specific differences were identified in all odontometric variables, and an artificial neural network model was prepared that used odontometric variables for predicting the sex of the participants with an accuracy of > 80%. This model can be applied for forensic purposes, and its accuracy can be further improved by adding data collected from new subjects or adding new variables for existing subjects. The improvement in the accuracy of the model was demonstrated by an increase in the percentage of accurate predictions from 72.0-78.1% to 77.8-85.7% after the anterior Bolton ratio and age were added. Conclusions: The described artificial neural network model combines forensic dentistry and orthodontics to improve subject recognition by expanding the initial space of odontometric variables and adding orthodontic parameters.

• Geomechanics and Engineering
• /
• v.34 no.3
• /
• pp.233-250
• /
• 2023

This paper investigates the flexural analysis of isotropic, transversely isotropic, and laminated composite plates using a new higher-order normal and shear deformation theory. In the present theory, only five unknown functions are involved compared to six or more unknowns used in the other similar theories. The developed theory does not need a shear correction factor. It can satisfy the zero traction boundary conditions on the top and the bottom surfaces of the plate as well as account for sufficient distribution of the transverse shear strains. The thickness stretching effect is considered in the computation. A simply supported was considered on all edges of the plate. The plate is subjected to uniform and sinusoidal distributed load in the static analysis. Laminated composite, isotropic, and transversely isotropic plates are considered. The governing equations are obtained utilizing the virtual work principle. The differential equations are solved via Navier's procedure. The results obtained from the developed theory are compared with other higher-order theories considered in the previous studies and 3D elasticity solutions. The results showed that the proposed theory accurately and effectively predicts the bidirectional bending responses of laminated composite plates. Several parametric studies are presented to illustrate the various parameters influencing the static response of the laminated composite plates.

• Journal of Species Research
• /
• v.12 no.spc2
• /
• pp.45-53
• /
• 2023

In July 2018, solar saltern samples were collected from Siheung, Gyeonggi-do Province to obtain unrecorded haloarchaea in Korea. The samples were suspended in a 20% NaCl (w/v) solution, and serial dilution was performed in fresh DB Characterization media No. 2. The strains isolated in this study showed at least 98.7% sequence similarity or more compared to the previously reported. Finally, 16 haloarchaeal strains, which were not reported in Korea but validly published under the International Code of Nomenclature of Prokaryotes (ICNP), were obtained from a solar saltern in Siheung. These 16 isolates were allocated to the orders Halobacteriales and Haloferacales. The 10 Halobacteriales strains were classified into the family Halobacteriaceae and Haloarculaceae. Each family belonged to three genera, respectively. The other six Haloferacales belonged to the families Haloferacaceae and Halorubraceae. Each family belonged to genus genus, respectively. Collectively, the unrecorded haloarchaeal strains belonged to two orders, four families, and eight genera. During the research, the possibility of discovering previously unknown species in domestic solar saltern was established. Gram-staining, cell morphology, physiological and basic biochemical parameters, and phylogenetic analysis were all performed in this study and are described in detail for each strain.

• Korean Journal of Materials Research
• /
• v.33 no.9
• /
• pp.367-371
• /
• 2023

In this study we examine variations in the structure of perovskite compounds of LaBa₂Cu₂O₉, LaBa2₂CaCu₃O₁₂ and LaBa₂Ca₂Cu₅O₁₅ synthesized using the solid state reaction method. The samples' compositions were assessed using X-ray fluorescence (XRF) analysis. The La: Ba: Ca: Cu ratios for samples LaBa₂Cu₂O₉, LaBa2₂CaCu₃O₁₂ and LaBa₂Ca₂Cu₅O₁₅ were found by XRF analysis to be around 1:2:0:2, 1:2:1:3, and 1:2:2:5, respectively. The samples' well-known structures were then analyzed using X-ray diffraction. The three samples largely consist of phases 1202, 1213, and 1225, with a trace quantity of an unknown secondary phase, based on the intensities and locations of the diffraction peaks. According to the measured parameters a, b, and c, every sample has a tetragonal symmetry structure. Each sample's mass density was observed to alter as the lead oxide content rose. Scanning electron microscope (SEM) images of the three phases revealed that different Ca-O and Cu-O layers can cause different grain sizes, characterized by elongated thin grains, without a preferred orientation.

• Computers and Concrete
• /
• v.33 no.1
• /
• pp.27-39
• /
• 2024

In this study, the authors investigate the free vibration behavior of three-phases functionally graded sandwich plates using a novel nth-order shear deformation theory. These plates are composed of a homogeneous core and two face-sheet layers made of different functionally graded materials. This is the novel type of the sandwich structures that can be applied in many fields of mechanical engineering and industrial. The proposed theory only requires four unknown displacement functions, and the transverse displacement does not need to be separated into bending and shear parts, simplifying the theory. One noteworthy feature of the proposed theory is its ability to capture the parabolic distribution of transverse shear strains and stresses throughout the plate's thickness while ensuring zero values on the two free surfaces. By eliminating the need for shear correction factors, the theory further enhances computational efficiency. Equations of motion are established using Hamilton's principle and solved via Navier's solution. The accuracy and efficiency of the proposed theory are verified by comparing results with available solutions. The authors then use the proposed theory to investigate the free vibration characteristics of three-phases functionally graded sandwich plates, considering the effects of parameters such as aspect ratio, side-to-thickness ratio, skin-core-skin thicknesses, and power-law indexes. Through careful analysis of the free vibration behavior of three-phases functionally graded sandwich plates, the work highlighted the significant roles played by individual material ingredients in influencing their frequencies.

• Journal of Dental Anesthesia and Pain Medicine
• /
• v.24 no.2
• /
• pp.119-128
• /
• 2024

Background: In pediatric dentistry, fear and anxiety are common among children. Local anesthetics (LA) are widely used to control pain and reduce discomfort in children during dental treatment. Topical anesthetics play a vital role in reducing pain and the unpleasant sensation of a needle puncture in children. Peppermint oil has been extensively used for various diseases. However, its anesthetic properties remain unknown. Peppermint oil, used in mouthwashes, toothpastes, and other topical preparations has analgesic, anesthetic, and antiseptic properties. This study aimed to compare and evaluate pain perception following the topical application of peppermint oil versus lignocaine spray before an intraoral injection in children, aged 8-13 years. Method: Fifty-two children, aged between 8-13 years, who required local anesthesia for dental treatment were divided into two groups of 26 each by simple random sampling (Group 1: 0.2% peppermint oil and Group 2: lignocaine spray). In both groups, physiological measurements (e.g., heart rate) were recorded using pulse oximetry before, during, and after the procedure. Objective pain measurement (Sound Eye Motor (SEM) scale) during administration and subjective measuremeant (Wong-Baker Faces Pain Rating Scale (WBFPRS)) after LA administration were recorded. This was followed by the required treatment of the child. Physiological parameters were compared between the two groups using an independent t-test for intergroup assessment and a paired t-test and repeated-measures ANOVA for intragroup comparisons. The Mann-Whitney U test was used to analyze the pain scores. Results: Intragroup mean heart rates, before, during, and after treatment were statistically significantly different (P < 0.05). However, the intergroup mean pulse rates did not differ significantly between the two groups. The mean WBFPS score in the lignocaine spray group was 4.133 ± 2.06 was statistically different from that of the peppermint oil group (0.933 ± 1.03; P < 0.001^*). The mean SEM score was significantly lower in the peppermint oil group than that in the lignocaine spray group (P = 0.006). No negative effects were observed in this study. Conclusion: 0.2% peppermint oil was effective in reducing pain perception.