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        검색결과 3,061

        381.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Chinese cabbage or pakchoi (Brassica Rapa subsp. Chinensis) is one of the most popular vegetables in Korea. It is grown and consumed throughout the year because it has many benefits. This study reports on the growth performance of pakchoi grown in the hydroponic system using a Food Juke Box (FJB) under different light compositions. The chlorophyll content (CC), root fresh weight (RFW), and shoot fresh weight (SFW) were measured. Further, various vegetation indices (VIs), such as modified chlorophyll absorption in reflectance index (MCARI1), normalized difference vegetation index (NDVI), optimized soil-adjusted vegetation index (OSAVI), and structure insensitive pigment index (SIPI), were employed to predict SFW. The study results indicated a significant increase in the CC of pakchoi with different light treatments compared with the control. The CC was highest under treatment with 70% white light, 20% blue light, and 10% red light (T1) than under treatment with 50% white light, 30% blue light, and 20% red light (T2). All used VIs showed significant differences with different light combination treatments. There was no significant change in RFW and SFW between the control and T1. However, a significant reduction in RFW and SFW was observed in T2 compared with the control. A comparison between T1 and T2 demonstrated that RFW and SFW were increased by 23% and 25%, respectively, compared with those in T2. The correlation result showed that SFW had a significant positive correlation with RFW (0.76***). Further, a significant negative correlation was observed with OSAVI (−0.25*), MCARI1 (−0.54***), and CC (−0.19*). In conclusion, our findings implied that different light combinations in pakchoi affected the photosynthetic pigments although they did not improve SFW. This research will pave the way for pakchoi production in hydroponics using smart farming FJB. This will further promote plant development, especially for domestic consumption, and help fulfill the growing demand for leafy vegetables.
        4,000원
        382.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Extracellular vesicles (EVs) are nanovesicles that carry bioactive cargoes of proteins, lipids, mRNAs, and miRNAs between living cells. Their role in cellular communication has gained the attention of several research reports globally in the last decade. EVs are critically involved in sperm functions, oocyte functions, fertilization, embryonic development, and pregnancy. The review summarizes the state-of-theart of EVs research in the diagnostic and therapeutic (theranostic) potentials of the EVs during the pregnancy that might provide a solution for gestational disturbances such as implantation failure, maternal health problems, gestational diabetes, and preeclampsia. EVs can be found in all biological fluids of the fetus and the mother and would provide a non-invasive and excellent tool for diagnostic purposes. Moreover, we provide the current efforts in manufacturing and designing targeted therapeutics using synthetic and semi-synthetic nanovesicles mimicking the natural EVs for efficient drug delivery during pregnancy.
        4,200원
        383.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this work, the sulfonic acid group was introduced into the resorcinol–formaldehyde (RF) microspheres by the addition of p-phenolsulfonic acid during the polycondensation process of RF. The hydrophilicity of the sulfonated RF allowed KOH to infiltrate inside the microspheres, which enhanced the formation of mesopores in the carbon microspheres during the activation process by KOH. SEM and TEM observations and N2 adsorption measurements verified the formation of abundant mesopores in the porous carbon microspheres. The BET surface area of these mesoporous carbons exceeded 2000 m2/ g. In 17 m NaClO4 “water-in-salt” (WIS) electrolyte-based supercapacitor, the synthesized mesoporous carbon exhibited high specific capacitance of 170 F/g at current density of 0.5 A/g, comparable to those in regular KOH electrolyte. When graphite was used as current collectors, the symmetric cell could operate at 2.5 V, and the mesoporous carbon exhibited an energy density of 43 Wh/kg at power density of 0.25 kW/kg, and 25 Wh/kg at power density of 6.25 kW/kg, respectively, which were superior to those using Pt or stainless steel as current collectors. The mesoporous carbon/graphite was an excellent electrode in new-generation “WIS” electrolyte-based high-voltage supercapacitor due to their high energy and power density.
        4,000원
        384.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Sugarcane bagasse has been used as a substrate for the development of microporous nano-activated carbons for the treatment and elimination of dissolved materials from aquatic environment. The activated carbon was produced using chemical activation in one-step method with zinc chloride ( ZnCl2) as the activating agent at a carbonization temperatures range from 500 to 900 °C. The effects of temperature and time of carbonization on the activated carbon product properties were thoroughly studied. The activated carbons that resulted were characterized using the N2 adsorption/desorption isotherms, Brunauer–Emmett–Teller method (BET), pore property analysis, micropore (MP) surface area, t-plot surface area, TGA, FTIR, SEM, TEM, and EDX analyses. The prepared activated carbon’s point of zero charge, Boehm titration process, iodine removal percentage, and methylene blue number were also investigated. The prepared activated carbon’s maximum surface area was achieved using a 2/1 impregnation ratio (dried sugarcane bagasse/ZnCl2) at 600 °C temperature of carbonization and 60 min residence time. 1402.2 m2/ g, 0.6214 and 1.41 cm3/ g, respectively, were the largest surface area, total pore volume, and micropore volume. As the activation temperature increased, the total pore volume increased and the BET study measured a pore diameter of 0.7 nm and a mean pore diameter of 1.77 nm.
        5,700원
        385.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Diamond-like nanocomposite (DLN) has become a promising thin film for many fields of applications due to its unique and tunable properties. However, low optical bandgap and thermal stability limits its application in many fields particularly as antireflection coating on solar cell. In the present study, the DLN thin film has been deposited using a mixed liquid precursor by rf-PECVD process. Surprisingly the presence of nc-C60 in FCC structure in DLN matrix has been observed. The degree of crystallinity and diameter of C60 have been increased significantly after annealed at 850 °C. The film has been annealed at 850 °C to primarily investigate its feasibility as antireflection coating (ARC) in compatible with industrial solar cell fabrication process. The refractive index and optical bandgap of the film were around 1.80 and 4.10 eV, respectively. Moreover, the optical bandgap has decreased to some extent to 3.92 eV even after annealing at such high temperature. The high SiOx at% and embedded nc-C60 enhanced the optical transparency and thermal stability of the DLN film. The solar-weighted average reflection of DLN-coated textured silicon was reduced significantly to 1.91%. The C60 embedded DLN film has a great potential to apply in different optoelectronic devices especially in solar cell as ARC.
        4,000원
        386.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The production of macroalgae-derived adsorbent is of great importance to realize the idea of treating pollutants with invaluable renewable materials. Herein, a novel meso-micro porous nano-activated carbon was prepared from green alga Ulava lactuca in a facile way via chemical activation with zinc chloride. The resultant activated carbon possesses a significant specific surface area 1486.3 m2/ g. The resulting activated carbon was characterized and investigated for the adsorption of Direct Red 23 (DR23) dye from an aqueous environment. Batch method was conducted to study the effects of different adsorption processes on the DR23 dye adsorption from water. Isotherms and kinetics models were investigated for the adsorption process of DR23 dye. It was found that the adsorption data were well fitted by Langmuir model showing a monolayer adsorption capacity 149.26 mg/g. Kinetic experiments revealed that the adsorptions of DR23 dye can be described with pseudo-secondorder model showing a good correlation (R2 > 0.997). The prepared activated carbon from Ulava lactuca was exposed to a total of six regeneration experiments. The regeneration result proved that the fabricated activated carbon only loses 19% of its adsorption capacity after six cycles. These results clearly demonstrated the high ability of the obtained active carbon to absorb anionic dyes from the aqueous environment.
        4,900원
        387.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fluorescent nanostructures based on carbon, or carbon dots, are attracting much attention and interest because of their diverse properties which can be applied in several fields of knowledge, such as optics, biomedicine, environmental research, among others. Such properties are in part, derived from its intrinsic luminescence from tunable functional groups. In this work, we produced carbon nanodots (CND) using agro-industrial residues, such as Lolium perenne and malt bagasse. The methods used were conventional hydrothermal syntheses and microwave-assisted hydrothermal synthesis. To the best of our knowledge, this is the first time that carbon dots synthesized from this ryegrass type are reported. The synthesis methods were one step (no catalyst, base, or acid were added for passivation), and the functional groups responsible for the luminescence and high solubility in water were identified by infrared spectroscopy, being mainly C=O, C–OH, C–N, and N–H. According to our theoretical studies, the C=O group introduced a new energy level for electronic transitions that can affect the emission properties. Fluorescence images of osteoblasts using CNDs were acquired and their chelating property towards Pb2+ and Cr6+ detection was tested.
        4,200원
        388.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study examined the effects of hot deboning and the irradiation of raw pork on the physicochemical properties of pork sausages. Pigs were deboned with a carcass (loin surfaces) temperature of 5℃ (cold) or 15℃ (hot). Each deboned raw pork loins were then irradiated at 0 kGy or 4 kGy. Emulsion-type sausages were prepared from each treated meat with other ingredients including fat, ice, salt, phosphate, and seasoning powder. Then sausage products were analyzed for their physiochemical properties and microbial spoilage up to 10 days. Emulsion stability of sausage products with hot deboning was better than the cold carcass up to three days. Sausage products with irradiated hot carcasses showed less cooking loss than from non-irradiated carcasses on day 10. Hardness, gumminess, and chewiness of the sausages decreased significantly with increasing storage time for all sausage products (p<0.05), but the sausage products with irradiated hot carcasses showed a smaller reduction compared with non-irradiated. Lipid oxidation was not significantly different in the sausage products with hot or cold deboning (p>0.05), but the sausage products from non-irradiated meats showed changes from 0.43 to 1.59 (MDA mg/kg of meat) in 10 days (p<0.5). Total plate count and E. coli count were significantly lower in the sausage products from irradiated meat (p<0.05). Finally, irradiating hot deboned meat at 4 kGy can be an excellent alternative for producing raw meat for sausages with promising microbiological and physicochemical properties.
        4,000원
        389.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This work describes the facile synthesis of silver nanoparticle-decorated zinc oxide nanocomposite through a simple glycol reduction method. The silver nanoparticle-decorated zinc oxide nanocomposite-based pencil graphite electrode has been validated as a perceptive electrochemical sensing podium towards nitrite. The morphology of the prepared nanocomposite has been characterized via specific spectroscopic and electrochemical techniques. The sensor exhibits a notable enhancement in the cyclic voltammetric response to nitrite oxidation at an ideal peak potential of 0.76 V in pH 6.0 acetate buffer. Under optimum conditions of nitrite directly expanded with their concentration in the range from 30 to 1400 μM with a detection limit of 14 μM.
        4,600원
        390.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the present study, a novel electrochemical sensor for acetaminophen (AMP) which included quantum graphitic carbon nitride dots, g-C3N4QDs, was designed and conducted with molecular imprinted polymer (MIP). First, bulk g-C3N4 was generated with direct thermal polycondensation of melamine. After the treatment of the acidic solution containing H2SO4: HNO3 (1:1, v:v), the heating treatment at 200 °C on the dispersion provided g-C3N4QDs. In this respect, for nanomaterial characterization, some spectroscopic approaches were performed including Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) as well as electroanalytical methods such as electrochemical impedance (EIS) and cyclic voltammetry (CV). In accordance with the aims of the study, AMP imprinted electrode was formed after high electrocatalytic performance and linear range of 1.0 × 10– 11–2.0 × 10– 8 M and the LODs of 2.0 × 10– 12 was achieved. Eventually, an AMP-printed sensor was also used for AMP identification in pharmaceutical samples.
        4,300원
        391.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Green synthesis of graphene using leaf extracts as sustainable reducing and capping agents is a thrust area of research owing to its simplicity, eco-friendly nature and the ease of access to graphene. Moringa (Moringa oleifera Lam) plant is widely cultivated in India owing to its important medicinal and nutritional values. Inspired by these reports, herein we report a simple, green and economic synthesis of graphene, Moringa leaf extract employed reduced graphene oxide (MRGO) with excellent dye removal efficiencies. The MRGO is prepared by refluxing a mixture of aqueous dispersion of graphene oxide and Moringa leaf extract for 10 h. Further, we elucidated the role of synthesized MRGO in the removal of methylene blue (MB) and rhodamine B (RB) dyes through the sonochemical method. This as-synthesized material exhibited excellent dye removal efficiencies of about 93% and 87% against MB and RB dyes, respectively. Graphene with huge surface area expedited the better adsorption of dye molecules, thus, facilitated the better removal of the latter. Therefore, the superior dye removal efficiencies of MRGO were attributed to its adsorption capacity. This cost-effective synthetic approach of MRGO nanomaterial has a great potential for the innovative applications in water purification technology and find its place in further industrialization.
        4,200원
        392.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In view of the growing need for clean energy, supercapacitors (SC), especially those based on activated carbon (AC) and organic electrolyte are attracting great attention for their theoretically infinite life span. However, they still age much faster than expected due to certain mechanisms. Several researches is being conducted to understand these mechanisms, but so far, the chemical reactions at the phase boundary of the activated carbon electrodes and organic electrolyte have been very unclear. Some pathways have not yet been investigated; there is no research on the reactions that can take place between acetonitrile in the vapor phase and the oxides presented on the surface of activated carbons. For this reason, in this study, divided into two parts, the first based on a thermal simulation and the second based on an experimental study, we have systematically described the ageing mechanisms by determining the gas-phase reactions that can occur at the electrode–electrolyte interface. On the one hand, a thermal model of a supercapacitor cell using activated carbon and organic electrolyte technology has been developed. This model allowed us to study the temperature distribution of supercapacitors, and thus to determine the thermodynamic parameters related to the phenomena produced at the electrode–electrolyte interface. On the other hand, a thermo-gravimetric analysis coupled with gas phase infrared spectroscopy on the activated carbons of an aged supercapacitor of the same technology as that used in the simulation was carried out. The results obtained made it possible to identify the chemical groups produced by ageing.
        4,200원
        393.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, activated carbon derived from different agricultural by-products or bio-waste is receiving a great deal of attention due to its low or zero cost and environmental friendliness. In this work, flowers obtained from Borassus flabellifer (BFL) is used as a carbon source and potassium hydroxide (KOH) as activation precursor to produce activated carbon with high specific surface area and predominant micropore. The obtained carbon material was activated at 650 °C. The as-prepared sample had a specific surface area of 930.3 m2/ g and pore size distribution of 1.96 nm. The carbon material exhibited high electrochemical performance with a specific capacitance of 247 F/g at 0.5 A/g in 1 M H2SO4 electrolyte and an excellent cycling stability of 94% after 2500 cycles. A specific energy of 101.1 Wh/kg and a specific power of 4500 kW/kg were obtained. Based on the electrochemical properties exhibited by BFL, it could be used as an excellent electrode material for supercapacitor applications.
        4,000원
        394.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cost-effective and sustainable high-performance supercapacitor material was successfully prepared from cellulosic waste (Sapindus trifoliatus nut shells) biomass-derived activated carbon (CBAC) by physical activation method. The CBAC displays nanofiber morphology, high specific surface area (786 m2/ g), large pore volume (0.212 cm3 g− 1) which are evaluated using FESEM, BET and possessed excellent electrochemical behavior analyzed through various electrochemical methods. Moreover, the assembled symmetric CBAC//CBAC device exhibits high specific capacitance of 240.8 F g− 1 with current density of 0.2 A g− 1 and it is maintained to 65.6 F g− 1 at high current density of 2.0 A g− 1. In addition, the symmetric device delivers an excellent specific energy maximum of over 30 Wh kg− 1 at 400 W kg− 1 of specific power and excellent cycling stability in long term over 5000 cycles. The operation of the device was tested by light-emitting diode. Hence, CBAC-based materials pave way for developing large-scale, low-cost materials for energy storage device applications.
        4,200원
        395.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Vitrification methods are commonly used for mammalian reproduction through the long-term storage of blastocyst produced in vitro. However, the survival and quality of embryos following vitrification are significantly low compared with blastocyst from in vitro production (IVP). This study evaluates that the survival of frozen-thawed bovine embryos was relevant to mitochondrial superoxide derived mitochondrial activity. Here we present supplementation of the cryopreservation medium with Mito- TEMPO (0.1 μM) induced a significant (p < 0.001; non-treated group: 56.8 ± 8.7%, reexpanded at 24 h vs Mito-TEMPO treated group: 77.5 ± 8.9%, re-expanded at 24 h) improvement in survival rate of cryopreserved-thawed bovine blastocyst. To confirm the quality of vitrified blastocyst after thawing, DNA fragmentation of survived embryos was examined by TUNEL assay. As a result, TUNEL positive cells rates of frozenthawed embryos were lower in the Mito-TEMPO treated group (4.2 ± 1.4%) than the non-treated group (7.1 ± 3.5%). In addition, we investigated the intracellular ROS and mitochondrial specific superoxide production using DCF-DA and Mito-SOX staining in survived bovine embryos following vitrification depending on Mito-TEMPO treatment. As expected, intracellular ROS levels and superoxide production of vitrified blastocysts after cryopreservation were significantly reduced (p < 0.05) according to Mito-TEMPO supplement in freezing medium. Also, mitochondrial activity measured by MitoTracker Orange staining increased in the frozen-thawed embryos with Mito-TEMPO compared with non-treated group. These results indicate that the treatment of Mito-TEMPO during cryopreservation might induce reduction in DNA fragmentation and apoptosis-related ROS production, consequently increasing mitochondrial activation for developmental capacity of frozen-thawed embryos.
        4,000원
        396.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Because sows are industrially vital for swine production, monitoring for their health or disorder status is important to ensure high reproductive performance. Especially, ambient temperature changes in different season, especially during summer, are directly influenced to the reproductive performance of sows. Although the serum biochemical parameters are widely applied in the veterinary medicine with wide ranges for the physiological process, the values are also influenced by several factors such as age, breed, gender, and stress. In addition, domestic sows in Koreaspecific reference interval (RI) for serum biochemistry has not been established yet. Therefore, the present study was aimed to evaluate seasonal variation of RIs in the serum biochemistry in domestic sows in Korea at different seasons and to establish normal RIs using a RI finding program (Reference Value Advisor). Significant difference (p < 0.05) on the different seasons were identified in several serum biochemical parameters including BUN, CRE, GGT, GLU, ALB, TP, LDH and Na in sows. Therefore, we further established RIs, specific in domestic sows in Korea regardless of season. The established RIs based on the serum biochemical values provide a baseline for interpreting biochemical results in the domestic sows in Korea, regardless of seasonal effect. It may contribute to develop a strategy for better reproductive performance by improving breeding management practice and evaluating health of pig herds, which facilitate to avert the economic loss in summer infertility in sows.
        4,000원
        397.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study the effect of vitamin C administration on pregnancy rates during summer heat stress in dairy cows was examined. A total of 80 Holstein-Friesian cows were divided into control and treatment groups (n = 40 each). Control group animals were given 10 mL isotonic normal saline, and treatment group, Vitamin C (4 mg/kg) on artificial insemination day (day 0) and 4th, 8th and 12th day post insemination. Pregnancy diagnosis was performed on 30th day post insemination by ultrasonography. Blood samples were randomly taken from 11 animals from each group. Serum P4, GSH, MDA and plasma 8-OHdG levels were determined by using ELISA method. Results showed that 8-OHdG levels were lower in treatment group on day 4, 8 and 12 (p < 0.05) compared with the control group. Similarly, pregnancy rate was higher in treatment group (32.5%) than control (22.5%), respectively. However, MDA, P4 and GSH levels were similar in both groups at 4th, 8th and 12th day. A gradual increase in P4, and MDA levels, and a strong positive correlation between 0, 4th (r = 0.54), 4, 8th (r = 0.59) and 8, 12th (r = 0.51) day was found. Similarly, GSH levels also showed positive correlation at days 0, 4th (r = 0.47) and 4, 8th (r = 0.56). However, a strong negative correlation (r = -0.56) between MDA day 0, and GSH day 8 was found. In conclusion, vitamin C application during insemination period in postpartum cows increases pregnancy rate, and reduces oxidative stress metabolite 8-OHdG levels.
        4,000원
        398.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It is getting more intensified with the competition among participating companies for global market share in major industrial fields. The situation is accelerating especially within the top 5 market share, and these include electric vehicles, semiconductors, chemicals, and shipbuilding industries. The key to the advantage over the competition within a strategic group is which company leads the innovation in the field. On-the-ground innovation refers to job-based innovation. This paper aims to analyze job unit innovation in the structure of empowerment, LMX, and job crafting. Existing studies on job crafting have suggested a causal structure based on job design in the traditional sense, and there are not many scholars who study the causal structure using a job situational model. Therefore, this paper takes an approach from the perspective of the job situation. As a result of the study, LMX showed a moderating effect on the relationship between autonomy provision and job crafting. While, in the relationship between meaing-giving and cognitive crafting, there is no significant moderating effect shown on the relationship between autonomy provision and cognitive crafting. Therefore, the results of the analysis in this study suggest that the meaning of jobs and participation in decision-making should be managed in an integrated way in structural and design areas, not just qualitative factors such as empowerment and leadership.
        4,300원
        399.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Post-slaughtering storage of pork meat is important to improve the flavor and texture profile. Although irradiation of meat improves the keeping qualities of red meat, less work was done on the effect of quality in irradiated pork leg meat during post-slaughtering storage. Therefore, this study was done to compare low dosages of single beam irradiation treated pork leg meat on eating quality parameters over the nontreated meat stored at different storage temperatures. Freshly slaughter pig carcasses were brought to the irradiation unit for treatment. Pork leg meat was treated at 2 kGy with single beam. Treated (2 kGy) and non-treated pork leg meat were kept in three different temperatures as 2, 10 and 25°C for 1, 3 and 5 days and analyzed for cooking loss, shear force, color and nitrogenous flavor compounds. Cooking loss in day 5 in irradiated pork leg (30.29) was significantly lower than the control (33.27) (p<0.05). Shear force of treated (1.93) and non-treated (1.29) pork leg meat after day 5 had significant difference (p<0.05). “L*” and “b*” values of pork leg meat had significant difference at day 5 compared non treated leg meat (p<0.05) whereas the “a*” value was increased with storage time and temperature. Hypoxanthine level was significantly lower in pork leg meat at day 5 in treated (16.07) and non-treated (24.59) meats at 25°C (p<0.05) whereas the changes in AMP, IMP and Inosine was not significantly difference (p>0.05). As conclusion, post-slaughtering storage and irradiation with single beam of 2 kGy could ensure the meat quality of leg pork at even higher storage temperatures, with cooking loss, tenderness, flavor and the color which will be benefited in the processing industry.
        4,000원