The aim of this study was to evaluate the analytical performance of a curved capillary configurations on a U-tube structure used in a tabletop fully automated blood viscometer. Precision was assessed using normal and abnormal quality control materials measured repeatedly over 20 days across shear rates of 1–1000 s⁻1. Correlation between straight and curved capillary configurations was evaluated. Sample stability was also assessed at shear rates of 1 s⁻1 and 300 s⁻1 over three consecutive days. The curved capillary system demonstrated robust precision, with total coefficients of variation decreasing with increasing shear rate. Strong correlations were observed between straight and curved capillary measurements across all shear rates. Passing– Bablok regression showed slopes close to unity and intercepts near zero, while Bland–Altman analysis revealed minimal bias without shear-dependent trends. Whole blood viscosity remained stable over three days at both low and high shear rates (all p > 0.98). The curved capillary–based U-tube configuration provides analytically equivalent and stable whole blood viscosity measurements compared with conventional straight capillary systems, supporting its suitability for fully automated blood viscometer.

목적 : 본 연구의 목적은 HMD 기반 가상현실을 사용할 때 나타나는 사이버 멀미를 분석하기 위해 VR 사용 전후 안정뇌파의 정량적 분석 및 멀미 민감성(MSSQ)과 EEG 상대 파워가 상관관계를 보이는지 알아보고자 하였다. 방법 : 근거리 시력에 이상이 없는 성인 여성 11명을 대상으로 VR 사용 전후 안정상태 뇌파를 건식 전극 헤드 셋(DSI-24)을 사용하여 측정하였으며, 멀미 민감도는 MSSQ 설문을 통해 평가하였다. VR 사용 전후 비교는 Wilcoxon Signed-Rank Test를, 뇌파 변화량과 멀미 민감성 상관관계는 Spearman’s correlation analysis, 그 리고 뇌파 상대 파워 변화량(ΔEEG)이 멀미 민감도 집단 간 비교는 Mann-Whitney U Test를 실시하였다. 결과 : VR 사용 후 분석 결과 여러 부위에서 저주파 활동인 세타파(RT)는 일관되게 감소, 세타파 대비 베타파 비율(RMT, RSMT)과 같은 주의 집중 관련 지표는 증가하는 경향을 보였다. EEG 변화와 멀미 민감성 설문 점수 간의 상관분석 결과 측두엽(T6)과 두정엽(Pz) 영역에서 MSSQ와 유의한 상관관계를 확인하였다. 멀미 민감도가 높 은 그룹에서는 감각 통합을 담당하는 두정엽(Pz, P3, P4)영역의 베타파 대역 활성도가 유의하게 감소하였다. 결론 : VR 사용 후 후두엽 부위의 주의 집중 관련 비율 지표 증가는 정보처리과정 중 시각적 자극에 대한 자극 인지 등을 반영하는 것으로 볼 수 있으며, 두정엽과 상반된 결과가 나타난 것을 토대로 VR의 시각 자극과 신체 감 각의 불일치는 사이버 멀미를 유발한다는 근거를 제시한다.

목적: 한국 성인을 대상으로 세 가지 측정방법에 따른 평균 동공간거리를 제시하고 측정방식에 따른 차이를 평가하고 자 하였다 방법 : 숙련된 한명의 검사자가 세 가지 방법(PD 미터, PD 자, 자동안굴절력계)을 이용하여 단안 및 양안에서 원거리 동공간거리를 측정하였다. 정치는 평균±표준편차로 나타내었으며, Paired t-test를 이용하여 기기에 따른 측정값 평균의 차이를 비교하였다. Pearson correlation을 이용하여 측정방식 간 상관계수를 구하였으며, 두 기기 로 측정한 값의 일치도는 Bland-Altman plots 분석을 시행하여 95% 일치도 한계(일치도 하한, 일치도 상한)로 나타내었다. 결과 : 평균연령은 21±2.3세 이었으며, 성별은 남자가 47명(49.5%), 여자가 48명(50.5%)이었다. 세 가지 측 정 장비 모두 남자가 여자에 비하여 유의하게 컸다. 연구 대상자의 양안 평균 동공간거리는 PD 미터 62.53±3.22 mm, PD 자 63.16±3.29 mm, 자동안굴절력계 63.37±3.46 mm로 측정되었다. 대응표본 t검정을 이용하여 측정 방법에 따른 차이를 평가한 결과 PD 미터는 PD 자와 평균적으로 –0.64±2.84 mm의 차이를 보였고(p=0.031), 자 동안굴절력계와 평균적으로 -0.84±2.20 mm의 차이를 보였다(p<0.001). PD 자와 자동안굴절력계는 유의한 차이 를 보이지 않았다. 양안에서 95% 일치도 한계는 PD 미터와 PD 자가 –6.21∼4.93 mm, PD 미터와 자동안굴절력 계 –5.16∼3.47 mm, PD 자와 자동굴절력계 –6.49∼6.08 mm였다. 동공간 거리가 3.5 mm 이상 차이가 나는 경 우는 PD 미터와 PD 자가 18명(18.9%), PD 미터와 자동안굴절력계가 14명(14.7%), PD 자와 자동안굴절력계가 20명(21.1%)이었다. 결론 : 세 기기 간의 평균 차이는 모두 1 mm 이내로 임상적으로 유의한 수준의 불편을 유발하지 않는 범위로 판단되었으나 측정 방식에 따라 3.5 mm 이상 차이가 났던 14.7∼21.1%는 안경을 조제·가공하여 만들었을 때 측 정방식에 따른 오차로 인하여 시각적 불편 및 증상을 호소할 가능성이 있다.

This study investigated the influence of alloying elements on the elastic modulus variation of titanium alloys and conducted theoretical density calculations, yielding the following conclusions. In Ti-M (M=Zr, Ag, Au, and Cu) alloys, the Md value ranges from 2.89325 to 11.1530, and the Bo value ranges from 2.30180 to 3.22978. Ti-Zr alloys are most suitable as optimal dental implant materials in terms of electronic structural stability and strength. Ti–Au and Ti–Ag primarily contribute to biocompatibility, corrosion resistance, and antibacterial performance, while offering less benefit for mechanical strengthening. Ti-Cu, while having low structural stability, exhibits excellent antibacterial functionality and is therefore worthy of consideration as a supplementary alloying element. The physical properties of ‑titanium–based Ti–M binary alloys have been examined, and future research will focus on extending the study to ternary and quaternary titanium alloy systems.

The quality of various commercial silicon nitride raw powders was compared and evaluated. Various powder characteristics and sinterability of low-cost Chinese powders were compared with those of powders from advanced manufacturers. Powder characteristics such as particle size, agglomeration, impurity content, and β phase fraction, as well as bulk characteristics such as β phase fraction and sintered density were investigated. The Chinese powder showed characteristics that were inferior to the E10 powder from UBE, Japan in most evaluated characteristics, but were comparable to the powders from other advanced manufacturers. However, at high temperature sintering of 1,800 °C, the sintered density of the Chinese powder was noticeably lower than that of the other powders. The correlation between various powder characteristics and sintered density was also quantified using the Pearson correlation coefficient. In the 1,700 °C sintered specimens, the particle size and β phase fraction were found to have a strong negative correlation with the sintered density. In contrast, the 1,800 °C specimens did not show any powder properties with a strong correlation to the sintered density.

본 연구는 아마추어 러너에서 체성분이 폐 기능과 어떻게 연관되는 지를 검증하기 위해 수행한 단면 상관관계 연구이다. 만 20–45세의 아 마추어 러너 48명을 단일 방문으로 평가하였고, 생체전기저항분석기로 골격근량(skeletal muscle mass, SMM)과 체지방률(percent body fat, PBF)을 측정하였으며, 표준화된 폐 기능 지표로 노력성 폐활량 (forced vital capacity, FVC), 1초간 노력성 호기량(forced expiratory volume in 1 second, FEV1), 최대 자발적 환기량(maximal voluntary ventilation, MVV)을 평가하였다. 수집된 자료는 유의수준 .05에서 Pearson 상관분석과 단변량 선형회귀분석으로 검토하였다. 분석 결과, SMM은 FVC(r=.78, p<.01), FEV1(r=.74, p<.01), MVV(r=.55, p<.01) 와 유의한 양의 상관을 보였고, PBF는 FVC(r=−.5, p<.01)와 유의한 음의 상관, FEV1(r=−.35, p<.05)과 약한 음의 상관을 나타냈다. 회귀분석에 서는 SMM이 FVC(R²=.60), FEV1(R²=.54), MVV(R²=.31)를 각각 유의 하게 설명하였으며, PBF는 FVC(R²=.25)에 대해 유의한 음의 설명력을 보였다. 이러한 결과는 근육의 충분성이 환기 수행능력을 지지하고, 지 방의 과다 축적이 폐 용적 및 유량 지표에 불리하게 작용함을 시사한 다. 단면 설계와 BIA 기반 측정이라는 한계를 고려할 때 인과 해석은 신중해야 하나, 아마추어 러너의 호흡 수행능력 최적화를 위해 근력, 근 지구력 중심의 훈련과 체지방 관리가 유효한 표적이 될 수 있음을 제안 하며, 향후 종단, 중재 설계를 통한 인과성 검증과 이중에너지 X선 흡수 계측(dual-energy X-ray absorptiometry, DXA)/자기공명영상(magnetic resonance imaging, MRI) 및 중심성 지방 지표를 포함한 정밀 측정 이 요구된다.

Freshwater ecosystems support biodiversity and provide essential ecosystem services. In Korea, the Water Environment Information System monitors these ecosystems using separate biological and physicochemical indicators. Complex interactions occur among diverse biological taxa and physicochemical conditions. Thus, integrating heterogeneous monitoring data is crucial for accurately assessing ecosystem health. However, differences in data characteristics between the indicators present significant integration challenges. Given the scale and heterogeneity of the monitoring data, advanced analytical techniques are necessary to detect interactions among variables. This study aimed to identify key correlations among biological and physicochemical indicators by clustering similar variables and removing noise using the Hierarchical Density-Based Spatial Clustering of Applications with Noise (HDBSCAN) algorithm, followed by Spearman’s rank correlation coefficient and maximal information coefficient (MIC) analyses. HDBSCAN effectively eliminated noise indicators and grouped biological and physicochemical indicators into clusters based on shared characteristics, thereby enhancing the interpretability of the correlation analysis. Spearman analysis showed strong associations among biological indicators, particularly among species with similar ecological traits. MIC analysis further detected nonlinear associations between ecological assessment indices and specific biological species, which also reflected similar ecological characteristics. These findings are significant in that the comprehensive analysis of existing monitoring data revealed relationships within biological and physicochemical indicators while preserving the original purpose and function of each monitoring network. This study is expected to serve as a foundational resource for freshwater environmental monitoring and the development of effective management strategies.

본 연구는 최근 대중매체에서 언급되고 있는 한국인의 문해력 논란이 왜 한자어에 집중되고 있으며, 또 한자어가 왜 한국어의 문해력을 방해하는지를 고찰해 보고자 하였다. 비록 기존 연구의 주장이 있기는 하지만, 본문은 그 근원적 원인을 한국어에 서 한자어는 본래 외래어였다는 사실과 한국어와 인지구조가 다르다는 관점에서 출 발하였다. 그래서 본문에서는 먼저 한국어의 개념 논리와 언어습관이 시공간의 인식에서부터 중국어와 다르다는 각도에서 출발하여, 한국인의 한자 개념 이해와 한자어의 구조 방식, 더 나아가 의미의 이질화, 신조어의 변화 양상 또한 달라진다는 각도에서 다양 한 예를 통해 분석을 진행하였다.

This study aimed to elucidate the functional correlation between G-protein activation and Ca²⁺ signaling during hypotonic shock-induced cell swelling in human osteoblast-like cells. Calcium influx was investigated using fura-2 fluorescence imaging, specific channel blockers, and G-protein modulators such as cholera toxin (CTX) and pertussis toxin (PTX). The external solution contained hypotonic Na⁺, and 300 M Cd²⁺ was applied to assess the involvement of extracellular Ca²⁺ channels. Calcium influx was significantly inhibited by Cd²⁺, indicating an extracellular source of Ca²⁺ through specific channels. CTX prolonged the hypotonic Na⁺-induced elevation of intracellular Ca²⁺, while PTX completely abolished it. These results suggest the involvement of G-protein-mediated pathways in Ca²⁺ regulation. Furthermore, the CTX-induced potentiation implies regulation via the cAMP/protein kinase A signaling axis, indicating that stretch sensitivity may be modulated by hormone-activated adenylate cyclase. This study is the first to demonstrate a functional link between hypotonic stress-induced Ca²⁺ influx and G-protein activation in human osteoblast-like cells, potentially involving a novel Ca²⁺ channel regulated by the cAMP/PKA pathway.

Background: Obesity negatively affects balance and core muscles playing a crucial role in postural stability. However, little is known about the relationship between abdominal muscle thickness and balance in normal weight women. Objectives: This study aimed to investigate the relationship between abdominal muscle thickness and balance ability in normal-weight women in their 20s. Design: Cross-sectional observational study. Methods: Twenty-four healthy normal-weight women participated. Abdominal muscle thickness including the external oblique (EO), internal oblique (IO), and transverse abdominis (TrA) was measured by ultrasonography. Static balance was assessed during the One-leg standing test and Tetrax system, while dynamic balance was assessed using the Y-Balance and single leg triple hop tests. Pearson correlation analysis was conducted to examine the relationship between muscle thickness and balance performance. Results: IO thickness showed a negative correlation with static balance (r=- .42). EO thickness showed a positive correlation with single leg triple hop tests (r=.49-.58) and a negative correlation with posterolateral distance during YBalance test. Conclusion: Our findings suggested that abdominal muscles, specifically the IO and EO, are moderately related to balance performance in normal-weight young women. These findings demonstrated the potential benefit of targeted core strengthening interventions to improve postural stability and functional movement. Further studies involving additional muscles and diverse populations are recommended.

Myxomatous mitral valve disease (MMVD) is the most prevalent cardiac disease in dogs worldwide. Left atrial enlargement is a prominent feature associated with an increased risk of congestive heart failure in dogs with MMVD. Left atrial anteroposterior diameter (LAD) has been suggested as a supplementary parameter for evaluating LA size in various species. The purpose of our study was to establish a correlation between the left atrial anteroposterior diameter normalized to body weight (LADn) and N-terminal pro-brain natriuretic peptide (NT-proBNP) in dogs with MMVD and to assess the diagnostic potential of LADn for MMVD. We conducted this study on 35 dogs and categorized them into the control and MMVD groups. The control group consisted of 10 dogs, whereas the MMVD group included 25 dogs classified into stages B1, B2, and C according to the American College of Veterinary Internal Medicine (ACVIM) guidelines. LADn was measured using echocardiography, and NT-proBNP levels were assessed using a fluorescent immunoassay. In conclusion, LADn shows promise as a valuable diagnostic marker of MMVD in dogs. The strong positive correlation between LADn and NT-proBNP levels demonstrates the usefulness of LADn as a clinical index for evaluating cardiac function and disease progression in dogs with MMVD.

Board games are steadily growing, re-evaluating the value of analog communication in the digital age. This market growth has raised players' expectations for quality, leading to a growing demand for well-crafted, well-balanced games. Game balance is a crucial element in providing players with a fair and immersive experience. However, board game balancing has primarily relied on the designer's experience or intuition, or on small-scale testing, which is time-consuming, costly, and carries the risk of bias. Therefore, this study aimed to empirically analyze the core elements of balance perceived by players. Based on existing research, we derived four balance factors—fairness, variety, scalability, and ease of play—and three play experiences—immersion, aesthetics, and interactivity. We conducted a survey of 78 college students who played eight board games over an eight-week period, and performed correlation and multiple regression analyses. The results revealed that fairness and variety significantly influenced players' immersive experiences. Variety, ease of play, and scalability significantly influenced the aesthetic experience, while expandability and variety had the greatest impact on the interactivity experience. This study is significant in that it leads the discussion on board game balance to data-based empirical analysis and provides objective balance adjustment guidelines to game designers.

Polymeric materials are extensively utilized in various industrial applications, including as gas barriers, fuel cells, sensors, and in semiconductor processes, and are particularly critical to ensure sealing performance in high-pressure gas systems. The diffusivity and solubility of gases within polymers significantly influences their sealing efficacy and is closely related not only to polymer–gas interactions but also to the thermodynamic properties of the gases. Notably, gas solubility exhibits a quantitative correlation with critical temperature, attributed to the condensability of the gas molecules. In this study, the solubility of five pure gases (H2, He, N2, O2, Ar) with varying critical temperatures was quantitatively measured and analyzed under high-pressure conditions (1-10 MPa) in four polymers differing in structure and density. The experiments employed both volumetric and manometric methods to measure gas desorption concentration, with meticulous corrections for minor temperature and atmospheric pressure variations to ensure data accuracy. The results demonstrated that the logarithmic solubility of gases in polymers increases linearly with the gas critical temperature, consistent across all polymer samples. This finding aligns with predictions from the Non-Equilibrium Lattice Fluid (NE-LF) model, which has been shown to accurately describe gas solubility behavior in glassy polymers.