• Clinical and Experimental Pediatrics
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• 제62권7호
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• pp.274-280
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• 2019

Purpose: To analyze the growth response to growth hormone (GH) therapy in prepubertal patients with Noonan syndrome (NS) harboring different genetic mutations. Methods: Twenty-three patients with prepubertal NS treated at Pusan National University Children's Hospital between March 2009 and July 2017 were enrolled. According to the disease-causing genes identified, the patients with NS were divided into 4 groups. Three groups were positive for mutations of the PTPN11, RAF1, and SOS1 genes. The five genes undetected (FGU) group was negative for PTPN11, RAF1, SOS1, KRAS, and BRAF gene mutations. The influence of genotype was retrospectively analyzed by comparing the growth parameters after GH therapy. Results: The mean chronological age at the start of GH treatment was $5.85{\pm}2.67years$. At the beginning of the GH treatment, the height standard deviation score (SDS), growth velocity (GV), and lower levels of insulin-like growth factor-1 (IGF)-1 levels were not statistically different among the groups. All the 23 NS patients had significantly increased height SDS and serum IGF-1 level during the 3 years of treatment. GV was highest during the first year of treatment. During the 3 years of GH therapy, the PTPN11, RAF1, and SOS1 groups showed less improvement in height SDS, IGF-1 SDS, and GV, and less increase in bone age-to-chronological age ratio than the FGU group. Conclusion: The 3-year GH therapy in the 23 prepubertal patients with NS was effective in improving height SDS, GV, and serum IGF-1 levels. The FGU group showed a better response to recombinant human GH therapy than the PTPN11, RAF1, and SOS1 groups.

• Wind and Structures
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• 제28권1호
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• pp.31-47
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• 2019

The accurate prediction of snow distributions under the wind action on roofs plays an important role in designing structures in civil engineering in regions with heavy snowfall. Affected by some factors such as building shapes, sizes and layouts, the snow drifting on roofs shows more three-dimensional characteristics. Thus, the research on three-dimensional snow distribution is needed. Firstly, four groups of stepped flat roofs are designed, of which the width-height ratio is 3, 4, 5 and 6. Silica sand with average radius of 0.1 mm is used to model the snow particles and then the wind tunnel test of snow drifting on stepped flat roofs is carried out. 3D scanning is used to obtain the snow distribution after the test is finished and the mean mass transport rate is calculated. Next, the wind velocity and duration is determined for numerical simulations based on similarity criteria. The adaptive-mesh method based on radial basis function (RBF) interpolation is used to simulate the dynamic change of snow phase boundary on lower roofs and then a time-marching analysis of steady snow drifting is conducted. The overall trend of numerical results are generally consistent with the wind tunnel tests and field measurements, which validate the accuracy of the numerical simulation. The combination between the wind tunnel test and CFD simulation for three-dimensional typical roofs can provide certain reference to the prediction of the distribution of snow loads on typical roofs.

• 한국물환경학회지
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• 제35권5호
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• pp.432-438
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• 2019

The purpose of this study is to predict Trophic Diatom Index (TDI) in tributaries of the Han River watershed using the random forest algorithm. The one year (2017) and supplied aquatic ecology health data were used. The data includes water quality(BOD, T-N, $NH_3-N$, T-P, $PO_4-P$, water temperature, DO, pH, conductivity, turbidity), hydraulic factors(water width, average water depth, average velocity of water), and TDI score. Seven factors including water temperature, BOD, T-N, $NH_3-N$, T-P, $PO_4-P$, and average water depth are selected by the Correlation Feature Selection. A TDI prediction model was generated by random forest using the seven factors. To evaluate this model, 2017 data set was used first. As a result of the evaluation, $R^2$, % Difference, NSE(Nash-Sutcliffe Efficiency), RMSE(Root Mean Square Error) and accuracy rate show that this model is compatible with predicting TDI. To be more concrete, $R^2$ is 0.93, % Difference is -0.37, NSE is 0.89, RMSE is 8.22 and accuracy rate is 70.4%. Also, additional evaluation using data set more than 17 times the measured point was performed. The results were similar when the 2017 data set were used. The Wilcoxon Signed Ranks Test shows there was no statistically significant difference between actual and predicted data for the 2017 data set. These results can specify the elements which probably affect aquatic ecology health. Also, these will provide direction relative to water quality management for a watershed that must be continuously preserved.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제24권4호
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• pp.392-402
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• 2021

Purpose: The present study assessed the role of an amino acid-based formula (AAF) in the growth of infants with cow's milk protein allergy (CMPA). Methods: Non-breastfed, term infants aged 0-6 months with symptoms suggestive of CMPA were recruited from 10 pediatric centers in China. After enrollment, infants were started on AAF for two weeks, followed by an open food challenge (OFC) with cow's milk-based formula (CMF). Infants with confirmed CMPA remained on AAF until 9 months of age, in conjunction with a cow's milk protein-free complementary diet. Body weight, length, and head circumference were measured at enrollment and 9 months of age. Measurements were converted to weight-for-age, length-for-age, and head circumference-for-age Z scores (WAZ, LAZ, HCAZ), based on the World Health Organization growth reference. Results: Of 254 infants (median age 16.1 weeks, 50.9% male), 218 (85.8%) were diagnosed with non-IgE-mediated CMPA, 33 (13.0%) tolerated CMF, and 3 (1.2%) did not complete the OFC. The mean WAZ decreased from 0.119 to -0.029 between birth and enrollment (p=0.067), with significant catch-up growth to 0.178 at 9 months of age (p=0.012) while being fed the AAF. There were no significant changes in LAZ (0.400 vs. 0.552; p=0.214) or HCAZ (-0.356 vs. -0.284; p=0.705) from the time of enrollment to age 9 months, suggesting normal linear and head growth velocity. Conclusion: The amino acid-based study formula, in conjunction with a cow's milk proteinfree complementary diet, supported normal growth till 9 months of age in a cohort of Chinese infants with challenge-confirmed non-IgE-mediated CMPA.

• Journal of Chest Surgery
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• 제54권2호
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• pp.81-87
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• 2021

Background: Artificial grafts such as polyethylene terephthalate (Dacron) and expanded polytetrafluoroethylene (ePTFE) are used for various cardiovascular surgical procedures. The compliance properties of prosthetic grafts could affect hemodynamic energy, which can be measured using the energy-equivalent pressure (EEP) and surplus hemodynamic energy (SHE). We investigated changes in the hemodynamic energy of prosthetic grafts. Methods: In a simulation test, the changes in EEP for these grafts were estimated using COMSOL MULTIPHYSICS. The Young modulus, Poisson ratio, and density were used to analyze the grafts' material properties, and pre- and post-graft EEP values were obtained by computing the product of the pressure and velocity. In an in vivo study, Dacron and ePTFE grafts were anastomosed in an end-to-side fashion on the descending thoracic aorta of swine. The pulsatile pump flow was fixed at 2 L/min. Real-time flow and pressure were measured at the distal part of each graft, while clamping the other graft and the descending thoracic aorta. EEP and SHE were calculated and compared. Results: In the simulation test, the mean arterial pressure decreased by 39% for all simulations. EEP decreased by 42% for both grafts, and by around 55% for the native blood vessels after grafting. The in vivo test showed no significant difference between both grafts in terms of EEP and SHE. Conclusion: The post-graft hemodynamic energy was not different between the Dacron and ePTFE grafts. Artificial grafts are less compliant than native blood vessels; however, they can deliver pulsatile blood flow and hemodynamic energy without any significant energy loss.

• 한국전문물리치료학회지
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• 제28권3호
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• pp.200-207
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• 2021

Background: Postural control deficit is a major characteristic in patients with chronic ankle instability (CAI). Elastic ankle tapings are commonly used to facilitate postural control in patients with CAI as well as prevent relapse of a lateral ankle sprain. However, equivocal evidence exists concerning the effect of elastic ankle taping on postural control. Objects: This study aimed to evaluate the effects of elastic ankle tapings using kinesio taping (KT) and dynamic taping (DT) on static and dynamic postural control in patients with CAI. Methods: Fifteen subjects with CAI were participated in this study. The participants performed tests under three conditions (barefoot, KT, and DT). Static postural control was evaluated using the one-leg standing test (OLST) and dynamic postural control using the modified Star Excursion Balance Test (mSEBT). One-way repeated-measures analysis of variance was used to compare center of pressure (CoP) data and normalized mSEBT reach distances among the three conditions (with α = 0.05). Results: The CoP parameters (path length, ellipse area, and mean velocity) of the OLST significantly decreased on applying KT and DT compared with those when barefoot. The normalized reach distances in the anteromedial (AM), medial (M), and posteromedial (PM) directions of the mSEBT significantly increased with DT compared to that in the control condition. Further, the higher reach distances with KT compared with those in the control condition were obtained in the M and PM directions of the mSEBT. No significant differences were identified in any of the OLST and SEBT parameters between the two different taping applications. Conclusion: KT and DT improved static postural control during the OLST compared with the control condition. Moreover, these tapes improved dynamic postural control during the mSEBT compared to the control. Therefore, elastic ankle tapings are useful prophylactic devices for the prevention and treatment of ankle sprain in people with CAI.

• 한국항공우주학회지
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• 제50권1호
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• pp.67-74
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• 2022

일반적으로 동역학 방정식을 이용하여 항공기의 거동을 분석하기 위해서는 공기 역학적 성분이 필요하고, 이를 위해서는 진 대기속도가 필수적이다. 대기속도는 피토관과 같은 항공기의 탑재 장비를 이용하여 계측할 수 있으나, 상업용 항공기의 계측 데이터는 항공사 내규 관련 보안성 데이터를 포함할 수 있으므로 확보하기 어렵다. 일반인들이 이용할 수 있는 항적 데이터 중 하나로 방송형자동종속감시 데이터가 있으며 항공기의 속도를 대지속도 형태로 제공한다. 대지속도는 진 대기속도와 바람 속도의 합으로 표현된다. 본 논문에서는 일반인들이 획득 가능한 항적, 기상, 지형 데이터를 결합하여 진 대기속도를 추정하는 방법을 제시한다. 각 데이터를 통합하기 위해 좌표계를 일치시킨 후 고도 기준을 평균 해수면 고도로 통일하였다. 또한, 해상도가 가장 낮은 기상 데이터의 격자를 기준으로 보간을 수행하여 항적 데이터의 모든 점에 대한 바람 벡터를 산출하였다. 이러한 과정을 여러 항적에 적용하여 기상, 지형 데이터의 통합을 통해 진 대기속도를 추정하였다.

• 대한조선학회논문집
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• 제59권3호
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• pp.183-191
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• 2022

A design method for a propeller type rim-driven axial-flow turbine for a micro-hydropower system is presented. The turbine consists of pre-stator, impeller and post-stator, where the pre-stator plays a role as a guide vane to provide circumferential velocity to the on-coming flow, and the impeller as a rotational power generator by absorbing angular momentum of the flow. BEM(Blade Element Method), which is based on the turbine Euler equation, is employed to design the pre-stator and impeller blades. NACA 66 thickness form and a=0.8 mean camber line, which is widely accepted as a marine propeller blade section, is used for the pre-stator and turbine blade section. A CFD method, derived from the discretization of the RANS equations, is applied for the analysis of the designed turbine system. The design conditions of the turbine is confirmed by the CFD calculation. Turbine characteristic curve is calculated by the CFD method, in order to provide the performance characteristics at off-design operation conditions. The proposed procedures for the design of a propeller type rim-driven axial-flow turbine are established and confirmed by the CFD analysis.

• 대한조선학회논문집
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• 제59권3호
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• pp.141-148
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• 2022

A hybrid turbulence model has developed by combining a sub-grid scale model using dynamic k equation in LES with k-𝜔 SST model of RANS equation. To ascertain potential applicability of the hybrid turbulence model, fully developed turbulent channel flows at Re_𝜏=180 have been simulated of which computational domain has a top wall with coarse cells and a bottom wall with fine cells. The streamwise mean velocity and turbulent intensity profiles showed a good agreement with DNS data when using the hybrid model rather than using a single model in k-𝜔 SST or dynamic k equation models. Computational simulations of turbulent flows around KVLCC2 with a pre-swirl duct have been mainly performed using the hybrid turbulence model. Compared to the results obtained from RANS simulation with k-𝜔 SST model as well as LES with dynamic k equation SGS model, turbulent wakes of the duct in the present simulation using the hybrid turbulence model were very similar to that of LES. Also, the resistances acting on hull, rudder and duct in hybrid turbulence model were similar to those in RANS simulation whereas the viscous forces acting on the hull in LES had a significant error due to coarse cells inappropriate to the sub-grid scale model.

• 한국수자원학회논문집
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• 제55권7호
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• pp.557-563
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• 2022

수위-유량관계곡선식은 측정된 수위를 유량으로 변환하는 데 필요하며 유량측정 성과를 이용하여 개발된다. 수위-유량관계곡선식 개발에서 구간분리 위치는 수리적 특성과 하천단면 형상 등을 고려하여 결정되며 이 과정에서 개발자의 주관적인 판단이 개입되는 경우가 있다. 구간분리 위치는 수위-유량관계곡선식의 전체적인 형태를 결정할 정도로 중요하고 잘못된 구간분리는 수위-유량관계곡선식의 오류를 유발하게 되며 특히 외삽구간에서 큰 오류가 발생할 가능성이 높다. 또한 예산, 인력 등의 문제로 많지 않은 유량측정성과로 정확한 수위-유량관계곡선식을 개발하려면 하천의 단면형상 및 흐름 특성 등 수리적인 요소를 고려하여 구간을 분할해야 한다. 본 연구에서는 기존의 수위-평균유속, 수위-단면적, 수위-${\sqrt{Q}}$ 등 수리적 검토 방법을 살펴보고 이를 보완하여 구간분리 위치 결정에 있어서 주관성을 배제하고자 하였다. 구간분리 위치에 대한 적절성을 수위-유량관계곡선식 지수 (c)의 물리적인 의미를 고려하여 이를 검토하였다.