• Journal of Animal Science and Technology
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• v.44 no.2
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• pp.233-238
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• 2002

Meat quality of the domestic pork loins(n=537) classified by 3 groups(5.31-5.50, 5.51-5.70 and $\geq$5.71) according to pH at 24hr post-mortem(pH24) was investigated. In proximate chemical compositions, protein was highest and fat was lowest in the pork loins of pH24 5.31-5.50 group. Water holding capacity increased as pH24 increased, whereas purge loss and cooking loss decreased as pH24 increased. Meat color values(CIE L*, a*, b*, Chroma, Hue and $\Delta$E) decreased as $pH_{24}$ increased. In texture traits, hardness and chewiness were lowest and fat hardness was highest in the pork loins of $pH_{24}{\geq}$5.71 group when compared to the other $pH_{24}$ groups. However, Warner-Bratzler Shear force, springiness and cohesiveness were not significantly different among the pH24 groups(P>0.05). In sensory properties, juiciness and tenderness were highest in $pH_{24}{\geq}$5.71 group. From the results of this study, pork quality was highly related to $pH_{24}$. Therefore, the factors affecting the post-mortem pH, such as stress before slaughter, slaughtering methods, and cooling condition slaughter must be properly controlled and improved to produce high quality pork.

• Food Science of Animal Resources
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• v.36 no.1
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• pp.29-36
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• 2016

This study was performed to investigate the role of pH and temperature postmortem, and to demonstrate the importance of these factors in determining meat quality. Postmortem pH_45min (pH at 45 min postmortem or initial pH) via analysis of Pearson’s correlation showed high positive correlation with pH change pH_c24 (pH change from pH_45min to pH_24h postmortem). However, postmortem pH after 24 h (pH_24h or ultimate pH) had a high negative correlation with pH change, pH_c24, CIE L*, and protein content. Initial temperature postmortem (T_1h ) was positively associated with a change in temperature from 45 min to 24 h postmortem (T_c24) and cooking loss, but negatively correlated with water holding capacity. Temperature at 24 h postmortem (T_24h) was negatively associated with T_c24. Collectively, these results indicate that higher initial pH was associated with higher pH_c24, T_1h, and T_c24. However, higher initial pH was associated with a reduction in carcass weight, backfat thickness, CIE a* and b*, water holding capacity, collagen and fat content, drip loss, and cooking loss as well as decreased shear force. In contrast, CIE a* and b*, drip loss, cooking loss, and shear force in higher ultimate pH was showed by a similar pattern to higher initial pH, whereas pH_c24, carcass weight, backfat thickness, water holding capacity, fat content, moisture content, protein content, T_1h, T_24h, and T_c24 were exhibited by completely differential patterns (p<0.05). Therefore, we suggest that initial pH, ultimate pH, and temperatures postmortem are important factors in determining the meat quality of pork.

• Development and Reproduction
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• v.21 no.2
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• pp.151-156
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• 2017

High-fructose corn syrup (HFCS) is widely used as sweetener, and its overconsumption is become a major health problem. In the present study, we used adult female rats and applied a 28 days HFCS feeding model to monitor the estrous cycle and changes in tissue weights and histology. Adult female rats were divided into three groups. Animals were fed with ad libitum normal chow and (1) 24 hours tap water (Control group), (2) 12 hours HFCS access during dark period and 12 hours tap water (12H group), and (3) 24 hours HFCS only access (24H group). Total exposure period was 28 days. There is no significant change in body weight between control and HFCS-fed animals. Both absolute and relative weights of ovary in 24H animals were significantly heavier than those in control or 12H animals. The absolute and relative weights of the kidney and liver in 24H groups were significantly heavier than those in control or 12H animals. The estrous cycles of the 24H animals were significantly longer. Histological analyses revealed that 24H ovaries were relatively bigger and possessed more corpus lutea than control ovaries. Uterine sections of 12H and 24H animals showed a well-developed stratum vasculare between inner and outer myometrial layers. The number of endometrial glands were decreased in 12H uteri, and recovered in 24H uteri compared to control. Numbers of convoluted tubule in distal region increased in 12H and 24H kidney samples. Liver specimens of 12H and 24H showed the increased number of fat containing vacuoles. In conclusion, our study demonstrated that HFCS treatment for 28 days could induce (1) changes in length of estrous cycle with extended estrous and diestrous stages, (2) altered ovarian and uterine histology, and (3) liver and renal lipid accumulation. These findings reveal the adverse effects of HFCS drinking on the reproductive function and lipid metabolism of female rats.

• Korean Journal of Veterinary Research
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• v.49 no.3
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• pp.253-256
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• 2009

The aim of the present study was to determine the acute and subacute potential of trichlorfon in guppies (Poecilia reticulatus). We first defined the 24 h median tolerance limit ($TLm_{24h}$) of the fish to trichlorfon. Guppies were then treated with $TLm_{24h}$ and 1/10 $TLm_{24h}$ trichlorfon concentrations to evaluate if any histological alterations occurred. The $TLm_{24h}$ value of trichlorfon was 11 ppm. This concentration resulted in acute toxicity to the gills and kidneys with edema, hyperplasia of the gill lamellae, and vacuolated degeneration and necrosis of renal tubular cells. In the case of subacute toxicity using a 10-fold dilution of the $TLm_{24h}$ value (1.1 ppm), no behavioral changes, external lesions or histopathological changes were observed. Therefore, safe concentration of trichlorfon might be 1.1 ppm in guppy for controlling parasitic infections.

• Journal of Welding and Joining
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• v.30 no.5
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• pp.70-75
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• 2012

This study is related to the laser weldability of AZ31B magnesium alloy, an all-purpose wrought alloy with good strength and ductility. In general, AZ31B is classified into AZ31B-H24 and AZ31B-O depending on temper designation. Thus, in this study, the laser weldability of AZ31B-H24 and AZ31B-O was investigated and compared. CW Nd:YAG laser was used to produce bead and butt joints. And the effects of welding conditions on the weldability of these joints were examined in detail. As a result of this study, AZ31B-H24 was found to have thinner oxide film and smaller grain size compared with AZ31B-O. Due to such difference, in bead welding, AZ31B-H24 had more wide welding range for full penetration compared with AZ31B-O. Furthermore, it was also confirmed that AZ31B-H24 and AZ31B-O have different welding conditions to obtain stable keyhole in butt welding.

• Korean Journal of Food Science and Technology
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• v.34 no.1
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• pp.91-95
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• 2002

Effects of freeze-drying time on the microbiological, sensory, and other characteristics of freeze-dried kimchi were investigated to optimize freeze-drying time for kimchi. Quality attributes of freeze-dried kimchi, including number of lactic acid bacteria (LAB), pH, sensory properties, brittleness, rehydration property, moisture content, and microstructure of Chinese cabbage were observed for 24, 48 and 72 h, respectively. Number of LAB and pH of the kimchi freeze-dried for 24 h were significantly changed in comparison with those of the kimchi not freeze-dried. However, further freeze-drying did not change markedly number of LAB and pH. Overall acceptability of the sample freeze-dried for 48 of 72 h was better than that of the sample freeze-dried for 24 h. As freeze-drying time increased, brittleness of the dried sample increased, and rehydration property was improved while dried weight and moisture content of the sample decreased. In conclusion, the sample freeze-dried for 48 h was better than the sample freeze-dried for 24 or 72 h, based on sensory properties and other characteristics.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.8
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• pp.1174-1179
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• 2009

An experiment was conducted to study the effect of post-hatch feed deprivation on yolk sac utilization andsubsequent performance of young broiler chickens (280) up to 35 days of age. The experimental treatments included access to feed at 8 h intervals after hatch, up to 48 h (0, 8, 16, 24, 32, 40 or 48 h). Water was offered ad libitum to all the groups immediately after placement. Results indicated that chicks with access to feed immediately after hatch used up the residual yolk more quickly. Access to feed between 8-24 h post-hatch, supported faster utilization of residual yolk compared to those chicks that remained unfed for 40-48 h (p<0.05). Further, deprivation of feed up to 24 h did not alter the lipid and protein contents in residual yolk, but fasting of chicks beyond 24 h (32, 40 and 48 h) led to retention of higher lipid and lower protein content in the yolk sac (p<0.05). At 7 days of age, the weights of proventiculus and gizzard were not affected by feed deprivation up to 48 h. However, the liver, pancreas and jejunum recorded significantly (p<0.05) heavier weights in chicks that were fed during the initial 24 h period compared to delayed feeding (32-48 h). Chicks fed within 24 h after hatch gained significantly (p<0.05) higher weight at 5 weeks of age than those that received feed between 32 and 48 h. Feed deprivation for 48 h was more detrimental to growth than 24-40 h. This study revealed the significance of early posthatch feeding (<24 h) on faster utilization of yolk sac nutrients and optimum development of intestines and organs, culminating in improved weight gain (>10.5%) of broilers at 5 weeks of age.

• Journal of Food Hygiene and Safety
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• v.30 no.2
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• pp.210-216
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• 2015

This study was investigated about the antibacterial effects of aqueous garlic extract (AGE) against Escherichia coli O157:H7 (E. coli O157:H7), Salmonella typhimurium (S. typhimurium) and Staphylococcus aureus (S. aureus). The minimum inhibitory concentration (MIC) of AGE against E. coli O157:H7, S. typhimurium, and S. aureus was 24, 48 and 24 mg/mL, respectively. In addition, the minimum bactericidal concentration (MBC) of AGE against E. coli O157:H7, S. typhimurium, and S. aureus was all of 96 mg/mL. The growth of E. coli O157:H7 was significantly inhibited at the concentration of AGE 24 mg/mL at 24 hr post-incubation (p < 0.01), but that of S. aureus was not significantly inhibited at the same concentration. However, the growth of S. aureus at the concentration of AGE 96 mg/mL was significantly inhibited at 24 hr post-incubation compared to that of untreated bacteria (p < 0.01). At the concentration of AGE 48 (p < 0.05) and 96 mg/mL (p < 0.001), the growth of S. typhimurim was significantly inhibited at 24 hr after incubation compared to that of untreated bacteria. With the results of this study, AGE can be used as alternative to antibiotics and chemical food preservatives.

• Clinical and Experimental Pediatrics
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• v.46 no.12
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• pp.1242-1247
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• 2003

Purpose : Gastroesophageal reflux disease(GERD) is known as one of the most common causes of chronic cough, especially in children. The purpose of this study is to evaluate the efficacy of parameters from proximal esophageal 24-hr pH monitoring through its comparison with those of distal esophageal 24-hr pH monitoring that we generally use for diagnosis of GERD. Methods : We performed chest CT scans to find out the cause of chronic cough in infants with no clinical manifestation suggesting GERD. Then, in case that they had air space consolidation in posterior segment of both upper lobes and superior segment of both lower lobes(dependent position), we performed proximal and distal esophageal 24-hr pH monitoring. Results : The proximal and distal pH monitoring were performed in 17 infants(male 12; female five). The patients with positive pathologic reflux in proximal esophagus were 15 of 17(88.2%) and in distal esophagus were four of 17(23.5%). Reflux index and the total number of reflux episodes were statistically significantly lower in the proximal than in the distal esophagus(P<0.05). There was no correlation between each parameters of proximal and distal esophageal 24-hr pH monitoring. Conclusion : This study suggests that proximal esophageal 24-hr pH monitoring can be used as a very useful diagnostic tool in infants with chronic cough in which there are suspicions that it resulted from aspiration due to GERD.

• Proceedings of the Materials Research Society of Korea Conference
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• 1993.05a
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• pp.89-90
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• 1993