• Title/Summary/Keyword: Mixed Effects Models

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A Study on Acute Effects of Fine Particles on Pulmonary Function of Schoolchildren in Beijing, China

  • Kim, Dae-Seon;Yu, Seung-Do;Cha, Jung-Hoon;Ahn, Seung-Chul
    • Proceedings of the Korean Environmental Health Society Conference
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    • 2004.06a
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    • pp.193-196
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    • 2004
  • To evaluate the acute effects of fine particles on pulmonary function, a longitudinal study was conducted. This study was carried out for the schoolchildren (3rd and 6th grades) living in Beijing, China. Children were asked to record their daily levels of peak expiratory flow rate using portable peak flow meter (mini-Wright) for 40 days. The relationship between daily PEFR and fine particle levels was analyzed using a mixed linear regression models including gender, height, the presence of respiratory symptoms, and daily average temperature and relative humidity as extraneous variables. The total number of students participating in this longitudinal study was 87. Daily measured PEFR was in the range of $253{\sim}501L/min$. On the daily basis, a PEFR measured in the morning was shown to be lower than that measured in the evening (or afternoon). The daily mean concentrations of $PM_{10}$ and $PM_{2.5}$ over the study period were $180.2\;{\mu}g/m^3$ and $103.2\;{\mu}g/m^3$, respectively. The IQR (inter-quartile range) of $PM_{10}$ and $PM_{2.5}$ were $91.8\;{\mu}g/m^3$ and $58.0\;{\mu}g/m^3$. Daily mean PEFR was regressed with the 24-hour average $PM_{10}$ (or $PM_{2.5}$) levels, weather information such as air temperature and relative humidity, and individual characteristics including gender, height, and respiratory symptoms. The analysis showed that the increase of fine particle concentrations was negatively associated with the variability in PEFR. The IQR increments of $PM_{10}$ or $PM_{2.5}$ (at 1-day time lag) were also shown to be related with 1.54L/min (95% Confidence intervals -2.14, -0.94) and 1.56L/min (95% CI -2.16, -0.95) decline in PEFR.

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Effects of Fermented Milk with Mixed Strains as a Probiotic on the Inhibition of Loperamide-Induced Constipation

  • Kim, Byoung-Kook;Choi, In Suk;Kim, Jihee;Han, Sung Hee;Suh, Hyung Joo;Hwang, Jae-Kwan
    • Food Science of Animal Resources
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    • v.37 no.6
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    • pp.906-916
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    • 2017
  • To investigate the effects of a single bacterium and a mixture of bacteria as probiotics in loperamide-treated animal models, loperamide (3 mg/kg) was administered to SD rats to induce constipation. The individual lactic acid bacterial doses, Enterococcus faecium (EF), Lactobacillus acidophilus (LA), Streptococcus thermophilus (ST), Bifidobacterium bifidum (BB), Bifidobacterium lactis (BL), Pediococcus pentosaceus (PP), and a mixture of the bacteria were orally administered to loperamide-induced constipated rats at a concentration of $10^8CFU/kg$ for 14 days. The weights and water contents of their stools were found to be significantly higher in PP, CKDB (mixture of 5 strains except PP), and CKDBP (CKDB+PP) groups than in the normal (constipation not induced) and the control (constipation-induced) groups (p<0.05). The intestinal transit ratio was significantly higher in all probiotic-treated groups than in the control group, and was the highest in the CKDBP group (p<0.05). The mucosal length and mucus secretion were significantly improved in all probiotic-treated-groups, as compared to that in the control group, and the CKDBP group was found to be the most effective according to immunohistochemistry (IHC) staining and total short chain fatty acid content analysis (p<0.05). Lastly, PP, CKDB, and CKDBP showed relatively higher Lactobacillus sp. ratios of 61.94%, 60.31% and 51.94%, respectively, compared to the other groups, based on metagenomic analysis.

Analysis of cutting forces and roughness during hard turning of bearing steel

  • Bouziane, Abderrahim;Boulanouar, Lakhdar;Azizi, Mohamed Walid;Keblouti, Ouahid;Belhadi, Salim
    • Structural Engineering and Mechanics
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    • v.66 no.3
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    • pp.285-294
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    • 2018
  • An experimental study has been carried out to analyze the effect of cutting parameters (cutting speed, feed and depth of cut) and tool nose radius on the surface roughness and the cutting force components during hard turning of the AISI 52100 (50 HRC) steel with a ceramic cutting tool. The tests have been conducted according to the methodology of planning experiments, based on an orthogonal plan of Taguchi (L27). By using the response surface methodology (RSM), the components of the cutting force and the roughness of the machined surface were modeled and the effects of the input parameters were analyzed statistically by ANOVA and RSM. The results show that the feed (f), the tool nose radius (r), the cutting speed (Vc), the interaction between feed and tool nose radius ($f{\times}r$) as well as that of the quadratic effect ($f^2$) all have significant effects on the surface roughness (Ra). The feed is the most influencing factor with a contribution of 47.31%. The components of the cutting force were strongly influenced by the depth of cut, followed by the advance with a lower degree. By comparing the experimental values with those predicted by the models of the cutting force components and the surface roughness, it appears that they are in very good correlation.

Genotype by environment interaction for somatic cell score in Holstein cattle of southern Brazil via reaction norms

  • Mulim, Henrique Alberto;Pinto, Luis Fernando Batista;Valloto, Altair Antonio;Pedrosa, Victor Breno
    • Animal Bioscience
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    • v.34 no.4
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    • pp.499-505
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    • 2021
  • Objective: The objective of this study was to evaluate the genetic behavior of a population of Holstein cattle in response to the variation of environmental temperature by analyzing the effects of genotype by environment interaction (GEI) through reaction norms for the somatic cell score (SCS). Methods: Data was collected for 67,206 primiparous cows from the database of the Paraná Holstein Breeders Association in Brazil, with the aim of evaluating the temperature effect, considered as an environmental variable, distinguished under six gradients, with the variation range found being 17℃ to 19.5℃, over the region. A reaction norm model was adopted utilizing the fourth order under the Legendre polynomials, using the mixed models of analysis by the restricted maximum likelihood method by the WOMBAT software. Additionally, the genetic behavior of the 15 most representative bulls was assessed, in response to the changes in the temperature gradient. Results: A mean score of 2.66 and a heritability variation from 0.17 to 0.23 was found in the regional temperature increase. The correlation between the environmental gradients proved to be higher than 0.80. Distinctive genetic behaviors were observed according to the increase in regional temperature, with an observed increase of up to 0.258 in the breeding values of some animals, as well as a reduction in the breeding of up to 0.793, with occasional reclassifications being observed as the temperature increased. Conclusion: Non-relevant GEI for SCS were observed in Holstein cattle herds of southern Brazil. Thus, the inclusion of the temperature effect in the model of genetic evaluation of SCS for the southern Brazilian Holstein breed is not required.

Protective Effects of a Mixed Medicinal Herb Extract (NUC1) on Collagenase-Induced Osteoarthritis in Rabbits

  • Sung-Gyu Lee;Hyun Kang
    • Journal of Microbiology and Biotechnology
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    • v.33 no.11
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    • pp.1484-1494
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    • 2023
  • NUC1 (Nutraceutical compound 1) is an ethanol extract composed of a formulation based on medicinal herbs traditionally used for the treatment of arthritis in Korea and China. This study investigated the therapeutic effects of NUC1 on osteoarthritis (OA). The protective effect of NUC1 on OA was tested in a rabbit model of collagenase-induced arthritis (CIA) for 4 weeks. Results were compared among four groups (n = 9 per group): the normal group (untreated), the CIA group (vehicle control), the NUC1 group (CIA rabbits treated with 200 mg/kg NUC1), and the JOINS group (positive control, CIA rabbits treated with 200 mg/kg JOINS tablet). NUC1 significantly inhibited NO production (p < 0.05 at 125 ㎍/ml, p < 0.01 at 250 ㎍/ml, and p < 0.001 at 500 ㎍/ml) and iNOS expression in macrophages, in a concentration-dependent manner. NUC1 also inhibited the release and protein expression of MMP-1, 3, and 13, in TNF-α-induced chondrosarcoma cells in a concentration-dependent manner. In vivo, the MMP-1 and MMP-3 levels in synovial fluids were significantly (p < 0.05) lower in NUC1 group (77.50 ± 20.56 and 22.50 ± 7.39 pg/ml, respectively) than in the CIA group (148.33 ± 68.58 and 77.50 ± 20.46 pg/ml, respectively). Also, in histopathological, NUC1 ameliorated articular cartilage damage in OA by increasing the abundance of chondrocytes and proteoglycan in the articular cartilage. Thus, NUC1 showed promise as a potential therapeutic agent, and it can be generalized to a broader study population in different OA animal models.

Mode of Action of Water Soluble β-Glucan from Oat (Avena sativa) on Calorie Restriction Effect In-Vitro and In-Vivo Animal Models (In-Vitro, In-Vivo 동물모델에서 귀리 유래 수용성 베타-글루칸의 칼로리 제한 효과 작용기전 규명)

  • Kang, Hanna;Kim, Se-Chan;Kang, Yong Soo;Kwon, Young-In
    • The Korean Journal of Food And Nutrition
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    • v.30 no.6
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    • pp.1222-1228
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    • 2017
  • In the current study, we investigated the inhibitory activity of water soluble ${\beta}-glucan$ from oat (Avena sativa) against various digestive enzymes such as ${\alpha}-glucosidase$, sucrase, maltase and glucoamylase. Inhibition of these enzymes involved in the absorption of disaccharide can significantly decrease the post-prandial increase of blood glucose level after a mixed carbohydrate diet. The ${\beta}-glucan$ had the highest documented rate of small intestinal sucrase inhibitory activity (2.83 mg/mL, $IC_{50}$) relevant for potentially managing post-prandial hyperglycemia. Furthermore, we evaluated the effects of ${\beta}-glucan$ on the level of post-prandial blood glucose in animal model. The post-prandial blood glucose levels were tested two hours after sucrose/starch administration, with and without ${\beta}-glucan$ (100, and 500 mg/kg-body weight). The maximum blood glucose levels (Cmax) of ${\beta}-glucan$ administration group were decreased by about 23% (from $219.06{\pm}27.82$ to $190.44{\pm}13.18$, p<0.05) and 10% (from $182.44{\pm}13.77$ to $165.64{\pm}10.59$, p<0.01) in starch and sucrose loading test, respectively, when compared to control in pharmacodynamics study. The ${\beta}-Glucan$ administration significantly lowered the mean, maximum, and minimum level of post-prandial blood glucose at 30 min after meal. In view of the foregoing, it is felt that our findings suggest that ${\beta}-glucan$ from oat serves to reduce post-prandial blood glucose rise secondary to slower absorption of glucose in the small intestine, via carbohydrate hydrolyzing enzymes inhibition.

Investigation on the Turbulent Flow Characteristics of a Gun-Type Gas Burner with the Different Shape of Baffle Plate (배플판 형상이 다른 Gun식 가스버너의 난류유동 특성치 고찰)

  • Kim, Jang-Kweon;Jeong, Kyu-Jo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.4
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    • pp.475-485
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    • 2004
  • This paper was studied to investigate and compare the effects of inclined baffle plate on the turbulent flow characteristics of a gun-type gas burner through X-Y plane and Y-Z plane respectively by using X-probe from hot-wire anemometer system. For this purpose, two burner models with a cone-type baffle plate and a flat-type one respectively were used. The fast jet flow spurted from slits plays a role such as an air-curtain because it encircles rotational flow by swirl vanes and drives mixed main flow to axial direction regardless of the inclination of baffle plate. The inclined baffle plate causes axial mean velocity component and turbulent intensities etc. to be greatly concentrated towards the central part of a burner, and its effect especially appears in the range of about X/R=1.0-2.0. Also, it gives much larger size to axial mean velocity component and turbulent intensities etc formed near the slits in the range of X/R=1.4103. Especially the inclined baffle plate shifts more the Reynolds shear stress uw to the central region of a burner(Y/R=${\pm}$0.75) than the flat-type one, moreover it develops more strongly than uv.

Association of Leptin Polymorphism with Production, Reproduction and Plasma Glucose Level in Iranian Holstein Cows

  • Moussavi, A. Heravi;Ahouei, M.;Nassiry, M.R.;Javadmanesh, A.
    • Asian-Australasian Journal of Animal Sciences
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    • v.19 no.5
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    • pp.627-631
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    • 2006
  • The objective of this study was to evaluate the association of genetic differences in the bovine leptin gene and milk yield, reproduction, body condition score (BCS), and plasma glucose level in Iranian Holstein cows. In total, two hundred and thirty eight cows were used and genotyped for a restricted fragment length polymorphism at the leptin gene locus. Two genotypes, AA and AB, have been distinguished which have the frequencies of 0.89 and 0.11, respectively. The genotypes were distributed according to the Hardy - Weinberg equilibrium ($x^2$ = 0.733). During the first 12 wk of lactation, milk yield and composition, live weight, BCS and plasma glucose were measured in 50 cows. Data were analyzed based on a repeated measures ANOVA. During this period, milk yield and composition, live weight, BCS and plasma glucose level were similar among the genotypes. The first cumulative 60-d milk yield, 305-d milk yield, days to first breeding, days open and days from first breeding to conception using previous lactation records were also analyzed using Standard Least Square within mixed models. Fixed effects were year, season, parity and age at calving, and sire. For the reproductive traits the cumulative first 60-d milk yield was also added to the model. Animal was fitted as a random effect. A significant association was detected between the RFLP-AB genotype and 305-d milk yield (p<0.05). The first 60-d cumulative milk yield was similar for the two genotypes (p = 0.21) and tended to be higher in the heterozygous cows. The heterozygous genotypes at the above mentioned locus had a trend to better reproductive performance than the homozygous. The results demonstrate that the RFLP B-allele can yield a higher 305-d milk production with a trend to better reproductive performance.

A Study on Acute Effects of Ambient Air Particles on Pulmonary Function of Schoolchildren in Ulsan

  • Yu, Seung-Do;Kim, Dae-Seon;Cha, Jung-Hoon;Ahn, Seung-Chul;Lee, Jong-Tae
    • Proceedings of the Korean Environmental Health Society Conference
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    • 2003.06a
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    • pp.183-186
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    • 2003
  • To evaluate the effect of air pollution on respiratory health in children, we conducted a longitudinal study in which children were asked to record their daily levels of peak expiratory flow rate using potable peak flow meter (mini-Wright) far 4 weeks. The relationship between daily PEFR and ambient air particle levels was analyzed using a mixed linear regression models including gender, age in you, weight, the presence of respiratory symptoms, and relative humidity as an extraneous variable. The daily mean concentrations of PM$\_$10/ and PM$\_$2.5/ over the study period were 64.9$\mu\textrm{g}$/㎥ and 46. l$\mu\textrm{g}$/㎥, respectively. The range of daily measured PEFR in this study was 170-481 l/min. Daily mean PEFR was regressed with the 24-hour. average PM$\_$10/ (or PM$\_$2.5/) levels, weather information such as air temperature and relative humidity, and individual characteristics including sex, weight, and respiratory symptoms. The analysis showed that the increase of air particle concentrations was negatively associated with the variability in PEFR. We estimated that the IQR increment of PM$\_$10/ or PM$\_$2.5/ were associated with 1.5 l/min (95% Confidence intervals -3.1, 0.1) and 0.8 l/min (95% Cl -1.8, 0.1) decline in PEFR. Even though this study shows negative findings on the relationship between respiratory function and air particles, it is worth noting that the findings must be interpreted cautiously because exposure measurement based on monitoring of ambient air likely results in misclassification of true exposure levels and this is the first Korean study that PM$\_$2.5/ measurement is applied as an index of air particle quality.

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Disparity in opinions on lip protrusiveness in contemporary African American faces

  • Battle, Yvette;Schneider, Monica;Magder, Laurence;Pae, Eung-Kwon
    • The korean journal of orthodontics
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    • v.48 no.1
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    • pp.23-29
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    • 2018
  • Objective: In accordance with the changing demographics in the United States, orthodontists working on various ethnic populations should be more conscious when using the standardized profile analyses for the African American patient. The objective of this study was to examine whether the perception of lip protrusiveness in modern African American faces has changed. For this purpose, we investigated the most favorable African American lip profile using the opinions of 10 experienced and 10 newly trained younger orthodontists. Methods: Attractiveness was converted to a number on visualized analog scales. Comparative ranks on 16 African American profiles, with focus on lip protrusiveness and thickness, were made among the groups. Mixed-effects linear regression models were fit and group differences were estimated. Results: Younger orthodontists favored a more protrusive lip profile, and the variance in their perceptions was narrower than those of older orthodontists. Measurements related to upper lip protrusion showed the strongest correlation to attractiveness (r = -0.82). The association with attractiveness decreased linearly as the protrusiveness of the upper lip increased. Steiner's E-line was the most influential reference for determining the level of attractiveness for the older orthodontists, whereas upper lip protrusion was the most influential factor for the young orthodontists. Conclusions: An adequate level of lip protrusiveness and thickness should be essential for maintaining attractive esthetics in African American patients. Yet, a new set of standards for prominent lips in this population is necessary to reflect the current trend in the concept of a beautiful face in the modern world.