• 한국양식학회지
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• 제6권3호
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• pp.199-211
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• 1993

조피볼락을 절식시켰을 때 사료의 n-3HUFA 함량에 따른 체성분의 변화를 조사하기 위해 n-3HUFA 함량이 다를 6종의 사료 $(n-3HUFA\; 0\~1.5\%)$로 10주간 사육한 조피볼락을 9주간 절식시킨 결과, 9주 절식 후의 체중감소율은 $14.0\~l7.1\%$ 범위로서 n-3HUFA 함량이 높은 사료를 섭취한 실험구일수록 체중감소가 적었다. 절식기간 중 전어체의 일반성분에 있어서는 모든 실험구에서 수분함량이 증가하고 지질함량은 감소하는 경향을 보였으며, 특히 n-3HUFA 함량이 낮은 사료구$(n-3HUFA\;0\~0.3%)$에서 지질함량의 상대변화비율이 높았다 단백질함량은 n-3HUFA 첨가 사료구에서 모두 절식 5주째 까지는 감소하다가 그 이후에는 일정한 값을 유지한 반면, n-3HUFA 무첨가 사료구는 5주 이후에도 계속 감소하여 n-3HUFA 함량에 따른 차이를 나타내었다. 전어체의 극성지질은 절식기간 중 각실험구 모두 대체로 일정한 값을 유지하였으나, 비극성지질이 감소한 결과, 절식기간이 경과함에 따라 극성지질/비극성지질 비가 증가하여 비극성지질이 절식시의 주 에너지 원으로 사용되었다. 절식후 전어체 극성지질의 DHA 함량은 절식전에 비해 큰 폭으로 증가하였으나, 비극성지질의 지방산조성에는 특별한 변화가 없었다.

• ETRI Journal
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• 제34권3호
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• pp.330-340
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• 2012

In many applications of wireless sensor actor networks (WSANs) that often run in harsh environments, the reduction of completion times of tasks is highly desired. We present a new time-aware, energy-aware, and starvation-free algorithm called Scate for assigning tasks to actors while satisfying the scalability and distribution requirements of WSANs with semi-automated architecture. The proposed algorithm allows concurrent executions of any mix of small and large tasks and yet prevents probable starvation of tasks. To achieve this, it estimates the completion times of tasks on each available actor and then takes the remaining energies and the current workloads of these actors into account during task assignment to actors. The results of our experiments with a prototyped implementation of Scate show longer network lifetime, shorter makespan of resulting schedules, and more balanced loads on actors compared to when one of the three well-known task-scheduling algorithms, namely, the max-min, min-min, and opportunistic load balancing algorithms, is used.

• 신재생에너지
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• 제19권4호
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• pp.27-34
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• 2023

In this study, microalgal oil was extracted from Nannochloropsis oceanica cultured in an open raceway pond and converted into biodiesel using a solid acid catalyst. Microalgal oil was extracted from two types of microalgae with and without nitrogen starvation using the KOH-solvent extraction method and the fatty acid content and oil extraction yield from each microalgae were compared. The fatty acid content of N. oceanica was 184.8 mg/g cell under basic conditions, and the oil content increased to 340.1 mg/g under nitrogen starvation conditions. Oil extraction yields were 90.8 and 95.4% in the first extraction, and increased to 97.5 and 98.8% after the second extraction. Microalgal oil extracted by KOH-solvent extraction was yellow in color and had reduced viscosity due to chlorophyll removal. In biodiesel conversion using the catalyst SO₄^2-/HZSM-5, solvent-extracted oil showed a FAME content of 4.8%, while KOH-solvent-extracted oil showed a FAME content of 90.4%. Solid acid catalyst application has been made easier by removal of chlorophyll from microalgal oil. The FAME content increased to 96.6% upon distillation, and the oxidation stability increased to 11.07 h with addition of rapeseed biodiesel and 1,000 ppm butylated hydroxyanisole.

• Molecules and Cells
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• 제37권3호
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• pp.257-263
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• 2014

A mammalian cell renovates itself by autophagy, a process through which cellular components are recycled to produce energy and maintain homeostasis. Recently, the abundance of gap junction proteins was shown to be regulated by autophagy during starvation conditions, suggesting that transmembrane proteins are also regulated by autophagy. Transient receptor potential vanilloid type 1 (TRPV1), an ion channel localized to the plasma membrane and endoplasmic reticulum (ER), is a sensory transducer that is activated by a wide variety of exogenous and endogenous physical and chemical stimuli. Intriguingly, the abundance of cellular TRPV1 can change dynamically under pathological conditions. However, the mechanisms by which the protein levels of TRPV1 are regulated have not yet been explored. Therefore, we investigated the mechanisms of TRPV1 recycling using HeLa cells constitutively expressing TRPV1. Endogenous TRPV1 was degraded in starvation conditions; this degradation was blocked by chloroquine (CLQ), 3MA, or downregulation of Atg7. Interestingly, a glucocorticoid (cortisol) was capable of inducing autophagy in HeLa cells. Cortisol increased cellular conversion of LC3-I to LC-3II, leading autophagy and resulting in TRPV1 degradation, which was similarly inhibited by treatment with CLQ, 3MA, or downregulation of Atg7. Furthermore, cortisol treatment induced the colocalization of GFP-LC3 with endogenous TRPV1. Cumulatively, these observations provide evidence that degradation of TRPV1 is mediated by autophagy, and that this pathway can be enhanced by cortisol.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-1
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• pp.70-70
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• 2003

In mammalians, ketone bodies (acetoacetate, D(-)-3-hydroxybutyrate and acetone) are generated mainly in the liver via the 3-hydroxy-3-methylglutaryl-CoA pathway, carried to and utilized in extrahepatic tissues as an energy source during starvation and diabetes in particular due to their overproduction as the consequence of elevated fatty acid oxidation and lowered glucose metabolism. (omitted)

• ALGAE
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• 제32권2호
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• pp.161-170
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• 2017

Fourier Transform Infrared (FTIR) spectroscopy was used to study carbon allocation patterns in response to N-starvation in the nearly ubiquitous diatom Chaetoceros muellerii. The role of gene expression, protein synthesis and transamination on the organic composition of cells was tested by using specific inhibitors. The results show that inhibition of key processes in algal metabolism influence the macromolecular composition of cells and and prior cell nutritional state can influence a cell's response to changing nutrient availability. The allocation of C can thus lead to different organic composition depending on the nutritional context, with obvious repercussions for the trophic web. This also shows that C allocation in algal cells is highly flexible and that C (and the energy associated with its allocation) can be variably and rapidly partitioned in algal cells in response to relatively short term perturbations. Furthermore, the data confirm and extend the utility of infrared spectroscopy as a probe of the metabolic state of autotrophic cells.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권5호
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• pp.776-796
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• 2010

Integrated RFID-WSNs (wireless sensor networks) have recently been researched to provide object identities, sensing information, mobile service, and network functionalities. In integrated RFID-WSNs, the reader collision is one of the critical problems. Above all, due to the absence of universally applicable anti-collision protocols and the channel capture phenomenon, the medium access control protocols in integrated RFID-WSNs suffer from reader collision and starvation problems. In this paper, we propose an efficient MAC protocol, called EMP, to avoid the above problems in integrated RFID-WSNs. EMP is a CSMA-based MAC protocol which is compatible with sensor networks operating on integrated nodes which consist of an RFID reader and a senor node. EMP resolves not only the reader collision problem, but also the starvation problem using a power control mechanism. To verify the performance of EMP, we compared it with other anti-reader collision MAC protocols using simulations. As a result, the performance of EMP showed improvements in throughput, system efficiency, and energy consumption compared to the single data channel protocols (CSMA/CA, Pulse, and DiCa) in dense deployment environments.

• 한국수소및신에너지학회논문집
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• 제17권3호
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• pp.279-285
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• 2006

Recirculation for the unreacted fuel is necessary to improve the overall efficiency of the fuel cell system and to prevent fuel starvation since the fuel cell for a vehicle application is a closed system. In case of the automotive fuel cell, the ejector which does not require any parasitic power is good for the performance improvement and easy operation. It is essential to design the customized ejector due to the lack of the commercial ejector corresponding to the operating conditions of the fuel cell systems. In this study, the design methodology for the ejector customized to an automotive fuel cell is proposed. The model based sensitivity analysis prevents the time-consuming redesign and reduces the cost of developing ejector. As a result, the customized ejector to meet the desired performance within overall operating range has developed for the PEMFC automotive system.

• 생명과학회지
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• 제28권1호
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• pp.1-8
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• 2018

젖산탈수소효소(Lactate dehydrogenase, EC 1.1.1.27, LDH)의 기능을 확인하기 위해서 Ldh testis-specific C가 발현된 생쥐(Mus musculus)를 48 hr과 96 hr 기아상태로 유지시킨 후 조직들의 LDH 대사를 LDH 활성, 역학 및 동위효소를 분석하여 연구하였다. 골격근, 간 및 눈조직에서 LDH와 LDH $A_4$활성이 증가되어 혐기적 대사가 우세하였고, 심장과 신장조직의 LDH 활성은 감소되지만 LDH $B_4$ 활성이 증가되어 피루브산을 생성하는 호기적 대사가 우세하였다. 하지만 정소조직에서는 LDH $C_4$가 감소되었고, 뇌조직의 LDH 활성은 조직 중에서 가장 많이 증가되었지만 동위효소의 변화가 작고 피루브산의 양이 감소되었다. 신장조직을 제외한 조직들에서 $K{_m}^{PYR}$이 증가되어 피루브산에 대한 친화력이 감소된 것으로 확인되었다. 실험결과 Ldh-A, B가 발현된 조직에서는 상대 농도가 큰 동위효소의 활성이 증가되었으나 Ldh-A, B, C가 발현된 정소조직은 LDH $C_4$가 감소되어 기능이 저하되었으며 특히 뇌조직에서 LDH는 피루브산 환원효소로서 역할을 하는 것으로 확인되었다. 따라서 이 과정은 기아상태에서 에너지를 생성하는 기작이 될 수 있는 것으로 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제26권4호
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• pp.558-563
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• 2013

The present study was conducted to estimate energy requirements for maintenance in laying hens by using indirect calorimetry and energy balance. A total of 576 28-wk-old Nongda-3 laying hens with dwarf gene were randomly allocated into four ME intake levels (86.57, 124.45, 166.63 and 197.20 kcal/kg body weight $(BW)^{0.75}$ per d) with four replicates each. After a 4 d adaptation period, 36 hens from one replicate were maintained in one of the two respiration chambers to measure the heat production (HP) for 3 d during the feeding period and subsequent 3 d fast. Metabolizable energy (ME) intake was partitioned between heat increment (HI), HP associated with activity, fasting HP (FHP) and retained energy (RE). The equilibrium FHP may provide an estimate of NE requirements for maintenance (NEm). Results showed that HP, HI and RE in the fed state increased with ME intake level (p<0.05). Based on the regression of HP on ME intake, the estimated ME requirements for maintenance (MEm) was 113.09 kcal/kg $BW^{0.75}$ per d when ME intake equals HP. The FHP was decreased day by day with the lowest value on the third day of starvation. Except for lowest ME intake level, the FHP increased with ME intake level on the first day of starvation (p<0.05). The FHP at the two higher ME intake levels were greater than that at the two lower ME intake levels (p<0.05) but no difference was found between the two lower ME intake levels. Linear regression of HP from the fed state to zero ME intake yielded a value of 71.02 kcal/kg $BW^{0.75}$ per d, which is higher than the extrapolated FHP at zero ME intake (60.78, 65.23 and 62.14 kcal/kg $BW^{0.75}$ per d for the first, second and third day of fasting, respectively). Fasting time, lighting schedules, calculation methods and duration of adaptation of hens to changes in ME intake level should be properly established when using indirect calorimetry technique to estimate dietary NE content, MEm and NEm for laying hens.