• Asian-Australasian Journal of Animal Sciences
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• v.15 no.2
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• pp.247-253
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• 2002

Two experiments were conducted to investigate the impact of high temperature and dietary tryptophan (Trp) on performance, selected organ weights and plasma free amino acid (AA) concentrations in broiler chickens. In Experiment 1, exposure to $27-33^{\circ}C$ of chickens for 2 weeks from 2 weeks of age did not affect growth and plasma free AA concentration except for a decrease in the concentration of plasma tyrosine (Tyr). In Experiment 2, 2-week-old birds were allocated to one of three temperature treatments; $24^{\circ}C$ (control), $36^{\circ}C$ (heat stress, HS) and $24^{\circ}C$ pair-fed (24PF) for 2 weeks and fed on diets containing 50, 100 and 300% of NRC requirement for Trp. Heat stress caused a reduction of weight gain and feed intake irrespective of dietary Trp levels compared with control counterparts, while feeding of 300% Trp diet did not attenuate the reduced performance by HS exposure. In groups fed the 100% Trp diets, plasma aromatic AA (AAA) and Tyr concentrations were decreased in the HS birds compared with the 24PF group. Plasma concentrations in most of AA groups were increased by HS in chickens fed the 50% Trp diet, while those were not changed by HS in chickens fed the 300% Trp diet, compared with 24PF counterparts. The plasma Trp/LNAA (LNAA=large neutral AAs, which are comprised of BCAA, AAA and Trp) ratio was increased by HS in chickens fed the 100% Trp diet, while it was decreased in chickens fed on 50% Trp diet as compared with 24PF group. From these results, it is suggested that performance and plasma amino acid profile deranged by heat stress are modulated, at least, to be relieved from the heat stress by feeding 50% Trp diet but not at all by feeding 300% Trp diet. The involvement of altered plasma AA profiles, in particular plasma Tyr concentrations and Trp/LNAA ratio, is discussed in association with the performance characteristics of HS chickens.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.2
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• pp.257-264
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• 2019

Objective: Dairy cattle nutrient requirement systems acknowledge amino acid (AAs) requirements in aggregate as metabolizable protein (MP) and assume fixed efficiencies of MP used for milk protein. Regulation of mammary protein synthesis may be associated with AA input and milk protein output. The aim of this study was to evaluate the effect of nanoemulsified methionine and cysteine on the in-vitro expression of milk protein (casein) in bovine mammary epithelial cells (MAC-T cells). Methods: Methionine and cysteine were nonionized using Lipoid S 75 by high-speed homogenizer. The nanoemulsified AA particle size and polydispersity index were determined by dynamic light scattering correlation spectroscopy using a high-performance particle sizer instrument. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to determine the cytotoxicity effect of AAs with and without nanoionization at various concentrations (100 to $500{\mu}g/mL$) in mammary epithelial cells. MAC-T cells were subjected to 100% of free AA and nanoemulsified AA concentration in Dulbecco's modified Eagle medium/nutrient mixture F-12 (DMEM/F12) for the analysis of milk protein (casein) expression by the quantitative reverse transcription polymerase chain reaction method. Results: The AA-treated cells showed that cell viability tended to decrease (80%) in proportion to the concentration before nanogenesis, but cell viability increased as much as 90% after nanogenesis. The analysis of the expression of genetic markers related to milk protein indicated that; ${\alpha}_{s2}$-casein increased 2-fold, ${\kappa}$-casein increased 5-fold, and the amount of unchanged ${\beta}$-casein expression was nearly doubled in the nanoemulsified methionine-treated group when compared with the free-nanoemulsified methionine-supplemented group. On the contrary, the non-emulsified cysteine-administered group showed higher expression of genetic markers related to milk protein ${\alpha}_{s2}$-casein, ${\kappa}$-casein, and ${\beta}$-casein, but all the genetic markers related to milk protein decreased significantly after nanoemulsification. Conclusion: Detailed knowledge of factors, such nanogenesis of methionine, associated with increasing cysteine and decreasing production of genetic markers related to milk protein (casein) will help guide future recommendations to producers for maximizing milk yield with a high level of milk protein casein.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.6
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• pp.52-60
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• 2005

Ultra-precision positioning systems basically require high natural frequency and sufficient workspace. To cope with this requirement, flexure hinge mechanisms have been developed. However, previous designs are difficult to satisfy the functional requirements of the system due to difficulty in modeling and optimization process applying fur the independent axiomatic design. Therefore, this paper suggests a new design and design procedure based on semi-coupled, axiomatic design. A spatial 3-DOF parallel type micro mechanism is chosen aa an exemplary device. Based on preliminary kinematic analysis and dynamic modeling of the system, an optimum design is conducted. To check the effectiveness of the optimal parameters obtained by theoretical approach, simulation has been performed by FEM.

• Polymer(Korea)
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• v.33 no.4
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• pp.326-332
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• 2009

New humidity-sensitive monomer, N-methacryloyl-N'-ethyl-N'-propyl piperazinium bromide (MANEPPB) was prepared by the quaternization reaction of N-methacryloyl-N'-ethyl piperazine (MANEP) with 1-bromopropane. Polyelectrolytes derived from the copolymers composed of MANEPPB/MMN/AA=60/35/5, 70/25/5, 80/15/5, 90/5/5 and 95/0/5 were prepared for the humidity-sensitive membranes, which were fabricated on the gold electrode by dipping method and were crosslinked by reacting copolymers with aziridine crosslinker, trimethylolpropane tris(2-methyl-1-aziridinopropionate) (TTAP). When the resistance dependences on the relative humidity of the sensors were measured, it was found that the resistance varied three orders of magnitude between 20 and 90%RH, which was satisfied with the requirement for the common humidity sensor operating at ambient humidity. Their hysteresis, temperature dependence, frequency dependence, response and recovery time and water durability were measured and evaluated as a humidity-sensing membrane.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.11
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• pp.1623-1628
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• 2011

The effects of dietary lysine (Lys) at a fixed ratio to crude protein (CP) and essential amino acids (EAA) on early growth response of broilers were studied. Four diets were formulated to contain similar metabolizable energy (ME, 2,950 kcal/kg) but contained graded levels of incremental Lys (1.1, 1.2, 1.3 and 1.4%) while also increasing the dietary CP and EAA (methionine, methionine+ cystine, threonine and tryptophan) to maintain a constant ratio with Lys. Each diet was fed at random to 10 replicates of 6 chicks each throughout the experimental period (1-21 d). At the lowest concentration of Lys of 1.1% (19.04% CP), body weight gain (BWG) was lowest and feed conversion ratio (FCR) was poorest. The BWG increased and FCR decreased linearly as dietary Lys increased upto 1.3% (22.5% CP). Lowest feed consumption was observed in the dietary group that contained 1.1% Lys (19.04% CP) in the diet. Increasing the concentration of Lys to 1.2% (20.77% CP), significantly increased the feed consumption. The concentrations of protein, calcium, phosphorus and cholesterol in serum were not influenced by the variation in Lys contents in the diet. The humoral immune response as measured by antibody titre in response to SRBC inoculation was significantly lower in the diets containing 1.1% Lys compared to 1.4%. It is concluded that the Lys requirement of broilers is 1.3% (22.5% CP) during 0 to 21 days of age for eliciting optimum performance when a fixed ratio of Lys to CP (1:17.31) and essential AA is maintained (1:0.47 Met; 1:0.56 Thr; 1:0.17 Try).

• Journal of Aquaculture
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• v.17 no.4
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• pp.275-281
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• 2004

The present study was conducted to evaluate dietary requirements for essential fatty acids (EFAs) such as linoleic acid (LA, l8:2n-6), -lenolenic acid (LNA, 18:3n-3), or docosahexaenoic acid (DHA, 22:6n-3), eicosapentaenoic acid (EPA, 20:5n-3) and arachidonic acid (ARA, 20:4n-6) in juvenile eel Anguilla japonica cultured in a recirculating system for 16 weeks. The experimental diets contained 50% crude protein, 10% crude lipid and 3800 kcal/kg energy.Brown fish meal and blood meal were used as the main protein sources, while coconut oil, com oil and linseed oil were used as the lipid source to yield target fatty acids ratios. At the end of the trial, the effects of essential fatty acids supplementation on weight gain (WG), specific growth rate (SGR), feeding efficiency (FE), proximate composition andwhole body fatty acids contents were examined. WG, SGR, and FEof eels fed diet D2, D3, was significantly higher (P<0.05) than those of fish fed the other diets. Whole body HUFA concentration of eels fed D 1 was significantly lower (P<0.05) than those fed the other diets. HUFA/SFA (saturated fatty acids) ratio of whole body in eels fed diets D2, D3 and D6 were significantly higher than that of eels fed diet D1 (P<0.05).DHA/EPA ratio of whole body in eels fed diet D7was significantly higher than those fed the other diets; and eels fed diet D5 showed the lowest DHA/EPA ratio among all the dietary treatments (P<0.05).Based on the experimental results, we concluded that LNA (n-3) and LA (n-6) were necessary for optimum growth of juvenile eel, and the dietary requirement of LNA and LA were 0.35∼0.5% and 0.5∼0.65%, respectively.

• Journal of Yeungnam Medical Science
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• v.18 no.2
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• pp.226-238
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• 2001

Background: Anemia in chronic renal failure plays an important role in increasing morbidity of dialysis patients. The causes of the anemia are multifactorial. With using of erythropoietin(EPO) most of uremia-induced anemia can be overcome. However, about 10% of renal failure patients shows EPO-resistant anemia. Hyporesponsiveness to EPO has been related to many factors: iron deficiency, aluminum intoxication, inflammations, malignancies and secondary hyperparathyroidism. So I evaluated the improvement of EPO responsiveness after correction of above several factors. Materials and Methods: Seventy-two patients on hemodialysis over 6 months were treated with intravenous ascorbic acid(IVAA, 300 mg t.i.w. for 12 weeks), After administration of IVAA for 12 weeks, patients were classified into several groups according to iron status, serum aluminum levels and i-PTH levels. Indivisualized treatments were performed: increased iron supplement for absolute iron deficiency, active vitamin D3 for secondary hyperparathyroidism and desferrioxamine(DFO, 5 mg/kg t.i.w.) for aluminum intoxication or hyperferritinemia. Results: 1) Result of IVAA therapy for 12 weeks on all patients(n=72). Hemoglobin levels at 2, 4, 6 week were significantly elevated compared to baseline, but those of hemoglobin at 8, 10, 12 week were not significantly different. 2) Result of IVAA therapy for 20 weeks on patients with 100 ${\mu}g/l$ ${\leq}$ ferritin < 500 ${\mu}g/l$ and transferrin saturation(Tsat) below 30%(n=30). After treatment of IV AA for 12 weeks, patients were evaluated the response of therapy according to iron status. Patients with 100 ${\mu}g/l$ ${\leq}$ ferritin < 500 ${\mu}g/l$ and Tsat below 30% showed the most effective response. These patients were treated further for 8 weeks. Hemoglobin levels at 2, 4 week were significantly increased compared to baseline with significantly reduced doses of EPO at 2, 4, 6, 10, 12, 16, 20 week. Concomitantly significantly improvement of Tsat at 2, 6, 16, 20 week compared to baseline were identified. 3) Result of IVAA therapy for 12 weeks followed by DFO therapy for 8 weeks on patients with serum aluminum above 4 ${\mu}g/l$(n=12) Hemoglobin levels were not significantly increased during IVAA therapy for 12 weeks but dosages of EPO were significantly decreased at 2, 4, 6, 8 week during DFO therapy compared to pre-treatment status. Conclusion: IVAA can be helpful for the treatment of the anemia caused by functional iron deficiency and can reduce the dosage of EPO for anemia correction. And administration of low dose DFO, in cases of increased serum aluminum level, can reduce the requirement of EPO.