• 한국토양비료학회지
• /
• 제44권4호
• /
• pp.625-636
• /
• 2011

Cold-adapted bacteria survive in extremely cold temperature conditions and exhibit various mechanisms of adaptation to sustain their regular metabolic functions. These adaptations include several physiological and metabolic changes that assist growth in a myriad of ways. Successfully sensing of the drop in temperature in these bacteria is followed by responses which include changes in the outer cell membrane to changes in the central nucleoid of the cell. Their survival is facilitated through many ways such as synthesis of cryoprotectants, cold acclimation proteins, cold shock proteins, RNA degradosomes, Antifreeze proteins and ice nucleators. Agricultural productivity in cereals and legumes under low temperature is influenced by several cold adopted bacteria including Pseudomonas, Acinetobacter, Burkholderia, Exiguobacterium, Pantoea, Rahnella, Rhodococcus and Serratia. They use plant growth promotion mechanisms including production of IAA, HCN, and ACC deaminase, phosphate solublization and biocontrol against plant pathogens such as Alternaria, Fusarium, Sclerotium, Rhizoctonia and Pythium.

• 대한기계학회논문집A
• /
• 제36권1호
• /
• pp.97-102
• /
• 2012

원자력발전소의 대체교류발전기는 소내정전에 대처하기 위하여 설치되고 있다. 국내 원자력발전소에서 사용되고 있는 대체교류발전기의 구동형식은 대부분 디젤발전기이다. 가스터빈은 디젤발전기보다 구조가 간단하고 유지정비주기가 길다는 장점이 있지만 국내 원자력발전소에 적용사례가 없다는 단점이 있다. 본 논문의 목적은 APR+ 대체교류발전기의 구동형식을 선정하기 위하여 디젤발전기와 가스터빈의 민감도 분석을 하는 데 있다. 이를 위하여 디젤발전기와 가스터빈의 물리적 특성과 국내의 대체교류발전기 적용현황, 그리고 US-APWR의 비상발전기 및 대체교류발전기의 가스터빈 적용사례를 조사하였다. 마지막으로 신뢰도 데이터에 대한 민감도 분석과 신형 노형인 APR+에 가스터빈 대체교류발전기를 적용하여 노심손상빈도의 민감도를 분석하였다.

• 한국축산식품학회지
• /
• 제30권3호
• /
• pp.403-409
• /
• 2010

Accurate methods for the identification of closely related species or breeds in raw and processed meats must be developed in order to protect both consumers and producers from mislabeling and fraud. This paper describes the development of DNA markers for the discrimination and improvement of Korean native pig (KNP) meat. The KIT gene is related to pig coat color and is often used as a candidate marker. A 538 bp fragment comprising intron 19 of the pig KIT gene was amplified by PCR using specific primers, after which the PCR amplicons of a number of meat samples from KNP and three major improved breeds (Landrace, Duroc and Yorkshire) were sequenced in order to find a nucleotide region suitable for PCR-RFLP analysis. Sequence data showed the presence of two nucleotide substitutions, g.276G>A and g.295A>C, between KNP and the improved pig breeds. Digestion of KIT amplicons with AccII enzyme generated characteristic PCR-RFLP profiles that allowed discrimination between meats from KNP and improved pig. KNP showed three visible DNA bands of 264/249, 199, and 75 bp, whereas DNA bands of 249, 199, and 90 bp were detected in the three improved pig breeds. Therefore, the 75 bp DNA fragment was specific only to KNP, whereas the 90 bp DNA fragment was specific to the improved breeds. The breed-specific DNA markers reported here that target the KIT gene could be useful for the identification of KNP meat from improved pig meats, thus contributing to the prevention of falsified breed labeling.

• Nutrition Research and Practice
• /
• 제7권4호
• /
• pp.287-293
• /
• 2013

This study determined the effects of fucoxanthin on gene expressions related to lipid metabolism in rats with a high-fat diet. Rats were fed with normal fat diet (NF, 7% fat) group, high fat diet group (HF, 20% fat), and high fat with 0.2% fucoxanthin diet group (HF+Fxn) for 4 weeks. Body weight changes and lipid profiles in plasma, liver, and feces were determined. The mRNA expressions of transcriptional factors such as sterol regulatory element binding protein (SREBP)-1c, Carnitine palmitoyltransferase-1 (CPT1), Cholesterol $7{\alpha}$-hydroxylase1 (CYP7A1) as well as mRNA expression of several lipogenic enzymes were determined. Fucoxanthin supplements significantly increased plasma high density lipoprotein (HDL) concentration (P < 0.05). The hepatic total lipids, total cholesterols, and triglycerides were significantly decreased while the fecal excretions of total lipids, cholesterol, and triglycerides were significantly increased in HF+Fxn group (P < 0.05). The mRNA expression of hepatic Acetyl-CoA carboxylase (ACC), Fatty acid synthase (FAS), and Glucose-6-phosphate dehydrogenase (G6PDH) as well as SREBP-1C were significantly lower in HF+Fxn group compared to the HF group (P < 0.05). The hepatic mRNA expression of Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) and Acyl-CoA cholesterol acyltransferase (ACAT) were significantly low while lecithin-cholesterol acyltransferase (LCAT) was significantly high in the HF+Fxn group (P < 0.05). There was significant increase in mRNA expression of CPT1 and CYP7A1 in the HF+Fxn group, compared to the HF group (P < 0.05). In conclusion, consumption of fucoxanthin is thought to be effective in improving lipid and cholesterol metabolism in rats with a high fat diet.

• 대한불안의학회지
• /
• 제4권1호
• /
• pp.3-10
• /
• 2008

The purpose of this review was to investigate the neurophysiological and neuroimaging characteristics of patients with depression and anxiety reported in previous studies. A literature search was conducted using Medline and psychiatric textbooks. "Electroencephalography (EEG)", "Event Related Potentials (ERP)", "functional neuroimaging", "heart rate variability (HRV)" and "depression or anxiety" were used as key words. A physiological finding indicated that there was a higher degree of relativity with regards to prefrontal dysfunction in patients with depression. Right prefrontal lobe hyperactivity and left prefrontal hypoactivity were consistently observed, and abnormalities were observed in other regions (ACC, hippocampus, amygdala, etc.). Therefore, dysfunctions in these areas are related to depressive symptoms. In patients with anxiety disorder, each emotional condition showed specific activation patterns in different brain regions, such as the prefrontal cortex, occipital lobe, temporal lobe, hippocampus, and limbic system, including the amygdala. However, in the majority of patients with anxiety disorder, the degree of activation was higher in the right hemisphere than in the left hemisphere. The current data supports that there is a difference in brain dysfunction characteristics between depression and anxiety and that the different activations of various brain regions would play a significant role in the pathophysiology of depression and anxiety disorder.

• Advances in concrete construction
• /
• 제8권3호
• /
• pp.207-215
• /
• 2019

Application of nanotechnology can be used to tailor made cementitious composites owing to small dimension and physical behaviour of resulting hydration products. Because of high aspect ratio and extremely high strength, carbon nanotubes (CNTs) are perfect reinforcing materials. Hence, there is a great prospect to use CNTs in developing new generation cementitious materials. In the present paper, a parametric study has been conducted on cementitious composites reinforced by two types of multi walled carbon nanotubes (MWCNTs) designated as Type I CNT (10-20 nm outer dia.) and Type II CNT (30-50 nm outer dia.) with various concentrations ranging from 0.1% to 0.5% by weight of cement. To evaluate important properties such as flexural strength, strain to failure, elastic modulus and modulus of toughness of the CNT admixed specimens at different curing periods, flexural bending tests were performed. Results show that composites with Type II CNTs gave more strength as compared to Type I CNTs. The highest increase in strength (flexural and compressive) is of the order of 22% and 33%, respectively, compared to control samples. Modulus of toughness at 28 days showed highest improvement of 265% for Type II 0.3% CNT composites. It is obvious that an optimum percentage of CNT could exists for composites to achieve suitable reinforcement behaviour and desired strength properties. Based on the parametric study, a tentative optimum CNT concentration (0.3% by weight of cement) has been proposed. Scanning electron microscope image shows perfect crack bridging mechanism; several of the CNTs were shown to act as crack arrestors across fine cracks along with some CNTs breakage.

• Advances in concrete construction
• /
• 제8권3호
• /
• pp.225-237
• /
• 2019

Although applying self-consolidating concrete (SCC) in many modern structures is an inevitable fact, the high consumption of cement in its mixing designs has led to increased production costs and adverse environmental effects. In order to find economically viable sources with environmentally friendly features, natural pozzolan pumice and blast furnace slag in 10-50% of replacement binary designs have been investigated for experiments on the properties of fresh concrete, mechanical properties, and durability. As a natural pozzolan, pumice does not require advanced equipment to prepare for consumption and only needs to be powdered. Pumice has been the main focus of this research because of simple preparation. Also to validate the results, in addition to the control specimens of each design, fly ash as a known powder has been evaluated. Moreover, ternary mixes of pumice and silica fume were investigated to enhance the obtained results of binary mixes. It was concluded that pumice and slag powders indicated favorable performance in the high percentage of replacement.

• Advances in concrete construction
• /
• 제8권3호
• /
• pp.239-246
• /
• 2019

Substitution of natural fine aggregates with industrial by-products like precious slag balls (PS Balls) offers various advantages like technical, economic and environmental which are very important in the present era of sustainability in construction industry. PS balls are manufactured by subjecting steel slag to slag atomizing Technology (SAT) which imparts them the desirable characteristics of fine aggregates. The main objective of this research paper is to assess the feasibility of producing good quality concrete by using PS balls, to identify the potential benefits by their incorporation and to provide solution for increasing their utilization in concrete applications. The study investigates the effect of PS balls as partial replacement of fine aggregates in various percentages (20%, 40%, 60%, 80% and 100%) on mechanical properties of concrete such as compressive strength, splitting tensile strength, and flexural strength. The optimum mix was found to be at 40% replacement of PS balls with maximum strength of 62.89 MPa at 28 days curing. Permeability of concrete was performed and it resulted in a more durable concrete with replacement of PS balls at 40% and 100% as fine aggregates. These two specific values were considered as optimum replacement is 40% and also the maximum possible replacement is 100%. Scanning electron microscope (SEM) analysis was done and it was found that the PS balls in concrete were unaffected and with optimum percentage of PS balls as fine aggregates in concrete resulted in good strength and less cracks. Hence, it is possible to produce good workable concrete with low water to cement ratio and higher strength concrete by incorporating PS balls.

• Advances in concrete construction
• /
• 제8권3호
• /
• pp.173-185
• /
• 2019

This article presents a comparative study of the effect of steel layouts on the seismic behavior of transition steel-concrete composite connections, both experimental and analytical investigations of concrete filled steel tube-reinforced concrete (CFST-RC) and steel reinforecd concrete-reinforced concrete (SRC-RC) structures were conducted. The steel-concrete composite connections were subjected to combined constant axial load and lateral cyclic displacements. Tests were carried out on four full-scale connections extracted from a real project engineering with different levels of axial force. The effect of steel layouts on the mechanical behavior of the transition connections was evaluated by failure modes, hysteretic behavior, backbone curves, displacement ductility, energy dissipation capacity and stiffness degradation. Test results showed that different steel layouts led to significantly different failure modes. For CFST-RC transition specimens, the circular cracks of the concrete at the RC column base was followed by steel yielding at the bottom of the CFST column. While uncoordinated deformation could be observed between SRC and RC columns in SRC-RC transition specimens, the crushing and peeling damage of unconfined concrete at the SRC column base was more serious. The existences of I-shape steel and steel tube avoided the pinching phenomenon on the hysteresis curve, which was different from the hysteresis curve of the general reinforced concrete column. The hysteresis loops were spindle-shaped, indicating excellent seismic performance for these transition composite connections. The average values of equivalent viscous damping coefficients of the four specimens are 0.123, 0.186 and 0.304 corresponding to the yielding point, peak point and ultimate point, respectively. Those values demonstrate that the transition steel-concrete composite connections have great energy dissipating capacity. Based on the experimental research, a high-fidelity ABAQUS model was established to further study the influence of concrete strength, steel grade and longitudinal reinforcement ratio on the mechanical behavior of transition composite connections.

• Advances in concrete construction
• /
• 제4권1호
• /
• pp.15-26
• /
• 2016

In Algeria, wastes are often stored in such conditions that do not meet standards. Today and more than ever, we really must implement an environmentally management of wastes. Recovery of waste in Algeria has a considerable delay due to the absence of a policy favorable to the development of waste management. But many researchers have shown the possibility to reuse dredged sediments in road construction. Through Europe, recent research works have been already performed on dam sediments. Present study fits into the context of the valorization of dredged sediments from Fergoug dam. They are found in considerable quantities and mainly composed of mineral phases, organic matters and water. The reservoir sedimentation poses problems for the environment and water storage, dredging becomes necessary. Civil engineering is a common way of recycling for such materials. Dredged sediments have not the required mechanical characteristics recommended by the standards as GTR guide (LCPC-SETRA 1992). So as to obtain mechanical performance, dredged sediment can be treated with cement, lime, or replaced materials like quarry sand. An experimental study has been conducted to determine physical and mechanical characteristics of sediments dredged from dam. Then different mixtures of sediment and/or quarry sand with hydraulic binders are proposed for improving the grain size distribution of the mixes. Finally, according these mixtures, different formulations have been tested as alternative materials with dredged sediments.