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Modified partial least squares method implementing mixed-effect model
Kyunga Kim,Shin-Jae Lee,Soo-Heang Eo,HyungJun Cho,Jae Won Lee 한국통계학회 2023 Communications for statistical applications and me Vol.30 No.1
Contemporary biomedical data often involve an ill-posed problem owing to small sample size and large number of multi-collinear variables. Partial least squares (PLS) method could be a plausible alternative to an ill-conditioned ordinary least squares. However, in the case of a PLS model that includes a random-effect, how to deal with a random-effect or mixed effects remains a widely open question worth further investigation. In the present study, we propose a modified multivariate PLS method implementing mixed-effect model (PLSM). The advantage of PLSM is its versatility in handling serial longitudinal data or its ability for taking a random-effect into account. We conduct simulations to investigate statistical properties of PLSM, and showcase its real clinical application to predict treatment outcome of esthetic surgical procedures of human faces. The proposed PLSM seemed to be particularly beneficial 1) when random-effect is conspicuous; 2) the number of predictors is relatively large compared to the sample size; 3) the multicollinearity is weak or moderate; and/or 4) the random error is considerable.
Kyungae Kim,MiRan Bang 한국간호과학회 2021 한국간호과학회 학술대회 Vol.2021 No.10
Aim(s): It is important to prevent the increase in the prevalence of diabetes mellitus (DM) worldwide by efficiently managing its controllable risk factors. This study aimed to identify factors associated with the 4-year estimated incidence of DM by gender and provide basic data for a gender-specific strategic approach to lifestyle modification. Method(s): In this study, we carried out a secondary data analysis using raw data from the seventh Korea National Health and Nutrition Examination Survey (KNHANES, 2016–2018). The KNHANES is a descriptive correlational survey designed to examine gender differences in the factors associated with the 4-year estimated incidence of DM. This study included 9,614 Korean adults (4,134 men and 5,480 women) aged 40-69 years without a diagnosis of DM. For statistical analysis, complex sample analysis was performed for gender comparison using χ2-test or one-way analysis of variance; multiple regression analysis was performed to analyze the gender-specific influencing variables of 4-year estimated DM incidence. Result(s): The waist-to-height ratio, an indicator of central obesity in adults, had the strongest association with the 4-year estimated incidence of DM in both groups (M: β=0.33, p≤0.001; F: β=0.38, p≤0.001). The influencing variables were monthly drinking rate (β=0.07, p≤0.001) and sleep time (β=-0.03, p<0.05) in men, and sedentary time in women (β=0.03, p<0.05). The overall explanatory power of these variables was 11.3% for men and 14.3% for women. Thus, significant gender differences were found in the 4-year estimated incidence of DM. Conclusion(s): Therefore, intervention programs need to be gender-specific to enhance the efficacy of the interventions in reducing the incidence of DM, and such intervention programs should be administered with a strategic approach differentiated by gender.
Non-invasive brain temperature monitoring using MR thermometry: in-vivo validation study
KyungA Kwak,Bitnarae Kwak,Taeim Kim,Kyung Sik Yi,ChulHyun Lee,Chi-Hoon Choi 한국실험동물학회 2021 한국실험동물학회 학술발표대회 논문집 Vol.2021 No.7
Purpose Non-invasive monitoring of brain temperature is essential for the assessment and optimization of therapeutic target temperature in acute ischemic brain. MR thermometry using 1-H MR spectroscopy (MRT) with Thulium-DOTMA (Tm-DOTMA) has the advantage of allowing absolute temperature measurements. We tried to validate MRT by comparing it with the actual brain temperature in rats. Materials and Methods Serial MRT was obtained in rats with mild systemic hypothermia (Group 1, n=5) and rats with local brain hypothermia with endovascular cooling (Group 2, n=5). Fiber optic thermometry (FOT) was inserted into the brain parenchyma to measure the actual temperature of the brain before MRT scans. For the local brain hypothermia models a 26G jelco catheter was inserted into the ICA and cold saline (4℃, 20ml) was infused in the MR bore for 20 minutes, followed by serial MRTs for 60 minutes. During MRT scans, body temperature was monitored using FOT. Tm-DOTMA was infused into the external jugular vein prior to an induced hypothermia. All the spectral data were semi-automatically processed by phasing and baseline correction using Philips software and JMRUI (URL http://www.mrui.uab.es/mrui/). Results The measured serial temperatures of FOT and MRT showed a similar linear decline in the systemic and local hypothermia groups. The differences of the measured temperatures between two methods were 0.05 ± 0.24 ℃ (mean±SD) in systemimc hypothermia group and 0.14 ± 0.34 in local brain hypothermia group. Conclusion In this study, we validated the MRT can monitor the selective brain hypothermia by confirming an accurate measurement of the actual brain temperature. Non-invasive brain temperature monitoring using the MRT is expected to be an important imaging biomarker for appropriate therapeutic hypothermia in the acute stroke patients.
Kyungae Jo,Ki-Bae Hong,Hyung Joo Suh 한국식품영양과학회 2020 Preventive Nutrition and Food Science Vol.25 No.1
In this study, we used various proteinases to investigate the effect of whey protein hydrolysates on proliferation and differentiation of MC3T3-E1 osteoblasts. To confirm hydrolysis of the whey protein hydrolysates, the yield and α-amino acid content were determined. Since osteogenic cell activity is an important factor in osteogenesis, we evaluated the proliferation of osteogenic cells by measuring 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and alkaline phosphatase (ALP) activity. To analyze bone matrix formation, we identified calcium deposition by staining with Alizaline red-S. The free amino acid content was significantly higher in the whey protein hydrolysates prepared using Protamex, Flavourzyme, and Alcalase than in the control. When cells were treated with 500㎍/mL of whey protein hydrolysates prepared using Protamex and Alcalase, cell proliferation increased by 120% and 130%, respectively, compared with the control group. In addition, ALP activity was significantly higher following treatment with 500㎍/mL of whey protein hydrolysates prepared using Protamex and Alcalase (142.61% and 135.06%, respectively; P<0.05). Furthermore, when treated with 125㎍/mL of the same hydrolysates, the rate of calcium deposition increased significantly to 157.56% compared with the control group (P<0.05). Therefore, our results suggest that whey protein hydrolysates prepared using Protamex and Alcalase may have more beneficial effects on osteoblast proliferation and bone health than those prepared using other proteolytic enzymes.