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        검색결과 94

        1.
        2025.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To enhance the fixed carbon content and recovery rate of flotation concentrates from low-grade natural flake graphite (NFG), this study employed synchronous ultrasonic flotation in combination with inorganic salt ion (NaCl) enhancement. Flotation experiments were conducted to investigate the synergistic effects of these two methods. X-ray photoelectron spectroscopy, contact angle analysis, laser particle-size analysis, Raman spectroscopy, infrared spectroscopy, zeta potential measurements, electron microscopy, and Debye length calculations confirmed that ultrasonic cavitation disrupted particle agglomeration and cleaned the graphite surface. This process generated fine micro-/nanobubbles with enhanced hydrophobicity, significantly improving concentrate recovery rates. NaCl addition compressed the double electric layer on particle surfaces and suppressed bubble coalescence, stabilizing the froth and promoting graphite–bubble adhesion, which markedly increased the fixed carbon content of the concentrate. The results demonstrated that through the integrated approach, low-grade NFG with an initial fixed carbon content of 7.98% was upgraded after rough processing to a concentrate containing 79.24% fixed carbon, with a recovery rate of 65.76%. These findings demonstrate that combining ultrasonic flotation with NaCl addition substantially improved both fixed carbon content and recovery rate in the concentrate. Overall, this study provides a novel technical pathway for the efficient utilization of low-grade graphite ore resources.
        5,800원
        2.
        2025.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Cigarette smoke is a well-known reproductive toxicant that causes structural and functional damage to the testis through oxidative stress and apoptotic pathways. This study aimed to evaluate whether apple seed extract (ASE) can mitigate testicular damage induced by tobacco smoke extract (TSE) in a mouse model. Methods: Adult male mice were orally administered TSE to induce testicular injury. ASE was delivered intraperitoneally, either as a post-treatment or concurrently with TSE. Histological evaluation (H&E staining), immunohistochemistry (IGF-1 and VEGF), and immunofluorescence (TNF-α, Caspase-3, and BCL-2) were conducted to assess tissue morphology, growth factor expression, and apoptotic signaling. Results: TSE exposure led to degeneration of the seminiferous tubules, suppressed IGF-1 and VEGF expression, and increased pro-apoptotic markers (TNF-α, Caspase-3), along with reduced BCL-2 expression. ASE treatment restored seminiferous tubule architecture, enhanced the expression of growth and anti-apoptotic factors, and attenuated apoptotic signals. These restorative effects were particularly significant in the post-treatment groups. Conclusions: ASE demonstrated protective and reparative effects against TSE-induced testicular toxicity by modulating oxidative and apoptotic pathways. These findings highlight ASE as a promising natural therapeutic candidate for ameliorating smokerelated male reproductive dysfunction.
        4,300원
        3.
        2025.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Plant-derived natural products, recognized for their bioactive properties and minimal side effects, have been widely explored for their potential in obesity management. Identifying plant-based agents that can modulate adipocyte function with low cytotoxicity is essential for developing safe and effective anti-obesity interventions. In this study, Philadelphus schrenkii (Korean mock orange) was identified as a promising candidate following an initial screening for agents that exhibit minimal cytotoxicity and reduced adipocyte differentiation, as assessed by Oil Red O staining. The anti-obesity effects of P. schrenkii methanol extract (PSE) were evaluated by using in vitro and in vivo models. PSE treatment significantly reduced C3H10T1/2 preadipocyte differentiation and upregulated thermogenic markers, including Ucp1 and Dio2, in differentiated cells. Although PSE did not induce weight loss, alter food intake, or improve the serum metabolic profiles in a diet-induced obesity mouse model, it notably enhanced the thermogenic Ucp1 expression in inguinal white adipose tissue (iWAT) and brown adipose tissue. It also mitigated high-fat diet-induced adiposity in iWAT, accompanied by Protein Kinase A signaling activation. These findings suggest that PSE modulates adipose tissue function by suppressing adipogenesis and promoting thermogenic gene expression without weight reduction or metabolic improvement. Based on these effects, PSE may contribute as a supportive agent to plant-based therapeutic strategies against obesity
        4,600원
        4.
        2025.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The nutrient composition of feed plays a crucial role in regulating gene expression in animals, thereby affecting growth, metabolism, and immune functions. In poultry, the optimized use of feed additives such as crude protein and phytase can enhance nutrient absorption, improve feed efficiency, and reduce environmental waste. In this study, we investigated the transcriptomic changes in the blood of forty-eight one-week-old broiler chickens fed diets differing in crude protein and phytase content. Using RNA sequencing and bioinformatic analysis, a total of 44 differentially expressed genes were identified in response to dietary variation. These genes were primarily involved in immune response, regulation of cell morphology, glycolytic process, and glycerolipid metabolism. Functional enrichment analysis revealed significant associations with cytokine–cytokine receptor interaction pathways, which regulate lipid metabolism, cellular proliferation, differentiation, and inflammatory responses. Moreover, decreased levels of crude protein and phytase were linked to alterations in protein autophosphorylation, amino acid biosynthesis, and energy metabolism pathways. These findings indicate that dietary modulation of crude protein and phytase levels can significantly influence metabolic and immune regulatory mechanisms in early-stage broilers. The appropriate feeding of feed additives (such as crude protein and phytase) not only improves nutritional deficiencies and feed efficiency issues in livestock, but also contributes to sustainable meat production, including the reduction of nitrogen and ammonia emissions, thereby supporting environmentally responsible poultry production.
        4,300원
        5.
        2025.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Alternative substrate materials for mushroom cultivation must be developed due to the unstable supply of the currently used substrates. Threonine acts as a nitrogen source in the substrate used for cultivating mushrooms. Threonine influences food flavor and participates in lipid metabolism and protein synthesis as well as energy metabolism through the tricarboxylic acid cycle. In this study, mushroom cultivation substrate was supplemented with threonine to evaluate the effects of threonine on the growth characteristics of and secondary metabolites produced by Pleurotus ostreatus. Threonine supplementation induced substantial changes in the parameters indicating the quality of fruiting bodies. These findings provide a basis for further research on supplementing substrates with amino acids for cultivating mushrooms.
        4,000원
        7.
        2025.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The constituents of coal tar pitch (CTP) significantly impact the wettability of calcined coke (CC) and the performance of prebaked anodes (PA) used in aluminum electrolysis. However, balancing wettability and carbon residue within CTP remains a central challenge in material applications. In addition, limited pore permeability and structural stability in these composites hinder the effective utilization of PA. Enhancing CTP fluidity is crucial for overcoming these challenges. In this work, a novel method was developed to modify CTP utilizing various coal tar fractions, enabling controlled modulation of CTP composition and wettability. Incorporating different fractions allowed for substantial control over interfacial bonding and pore structure. The chemical composition, functional groups, and elemental content of the CTP were analyzed via X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and proton nuclear magnetic resonance (1H NMR). Subsequently, systematic comparisons of PA materials produced from different CTP formulations demonstrated improved wettability and enhanced mechanical properties. Moreover, DFT calculations were performed to compare the adsorption energies of small molecules from different coal tar fractions with coke, reflecting the interaction strength between the molecules and the solid surface. Using micro-computed tomography (μ-CT), the refined pore structure was examined, resulting in a PA composite with an optimized balance of high strength and toughness.
        4,900원
        8.
        2025.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the area of carbon-based thin films, graphene/polyimide conductive films display remarkable heat resistance and mechanical properties, making them a valuable resource for utilisation in a multitude of manufacturing and living contexts. Nevertheless, modulating the interfacial structure between graphene and polyimide represents a significant challenge in the pursuit of enhancing the conductivity of the composite films, due to the elevated initial temperature of polyimide pyrolysis (exceeding 600 °C). To develop it, this study found that polyimide could undergo chemical bond breaking and atomic rearrangement at around 500 °C, when subjected to an applied electric field in graphene/polyimide films. A series of characterisations showed that the graphene/polyimide film formed a new interfacial structure under electrothermal treatment, which enhanced the electron transport capacity and increased its conductivity from about 1497.01 s m− 1 to about 2688.17 s m− 1, with an increase of about 79.57%. This study would provide the possibility of modulating the structure of polyimide below the pyrolysis temperature, as well as a feasible idea for transferring the properties of graphene into the polyimide matrix.
        4,900원
        11.
        2024.04 구독 인증기관·개인회원 무료
        Behavioral modulation by genetic changes garners a special attention nowadays as an effective means of revealing genetic function on the one hand and broadening the scope of in situ monitoring on the other hand. The cGMP-dependent protein kinase was treated to the western flower thrips, Frankliniella occidentalis. Automatic recognition techniques and computational methods were utilized to investigate behavioral changes across photo- and scoto-phases. Movement behaviors are objectively expressed according to parameter extraction and data structure visualization in different light phases. By comapring with the individuals without treatment, activities of treated thrips were changed including decrease in circadian rhythm. Usefulness of automatic monitoring of insect movement in different genetic strains is further discussed for providing useful information on monitoring and diagnosing natural and unntatural genetic disturbances.
        12.
        2024.04 구독 인증기관·개인회원 무료
        동물의 종 유지에 있어서 교미행동은 매우 중요한 위치를 차지함. 교미과정에서 수컷의 경우 모든 암컷에 대해 성행동을 보이는반면, 암컷은 가장 적절한 교미의 시기를 정하며, 적절한 수컷을 선택하고 교미행동을 보이기 때문에 암컷의 교미행동을 유도하는 과정은 생물학에서 매우 중요한 의미를 지님. 본 연구에서는 초파리 (Drosophila melanogaster) 전자현미경자료와 총신경망분석 (Connectomics)을 이용하여 초파리 뇌에서 암컷의 교미행동을 조절하는 것으로 알려진 pC1신경의 하부신경 pC1b,c가 성적 성숙과정에서 교미를 하고자 하는 욕구 (sexual drive)를 증가시키는 기능을 하는 것을 처음으로 밝힘. 본 연구에서는 처음으로 pC1b,c 신경 내의 cAMP 수준이 교미의 욕구변화를 보여주는 중요한 물질이라는 것을 밝혔고 cAMP의 수준이 오르기 위해서는 신경펩티 드인 Dh44와 그 수용체 GPCR인 Dh44R1과 Dh44R2가 필요하다는 것을 확인함. 또한 cAMP의 변화는 신경내의 CREBB를 통하여 하위 유전자인 pyx (pyrexia)의 발현을 유도한다는 것을 밝힘. 본 연구로 종 유지 메커니즘을 좀 더 이해할 수 있음.
        13.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Lead-free perovskite ceramics, which have excellent energy storage capabilities, are attracting attention owing to their high power density and rapid charge-discharge speed. Given that the energy-storage properties of perovskite ceramic capacitors are significantly improved by doping with various elements, modifying their chemical compositions is a fundamental strategy. This study investigated the effect of Zn doping on the microstructure and energy storage performance of potassium sodium niobate (KNN)-based ceramics. Two types of powders and their corresponding ceramics with compositions of (1-x)(K,Na)NbO3-xBi(Ni2/3Ta1/3)O3 (KNN-BNT) and (1-x)(K,Na)NbO3-xBi(Ni1/3Zn1/3Ta1/3) O3 (KNN-BNZT) were prepared via solid-state reactions. The results indicate that Zn doping retards grain growth, resulting in smaller grain sizes in Zn-doped KNN-BNZT than in KNN-BNT ceramics. Moreover, the Zn-doped KNNBNZT ceramics exhibited superior energy storage density and efficiency across all x values. Notably, 0.9KNN-0.1BNZT ceramics demonstrate an energy storage density and efficiency of 0.24 J/cm3 and 96%, respectively. These ceramics also exhibited excellent temperature and frequency stability. This study provides valuable insights into the design of KNNbased ceramic capacitors with enhanced energy storage capabilities through doping strategies.
        4,000원
        14.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        플라스틱은 전세계적으로 사용량이 증가함에 따라 해양 환경으로 유입되는 플라스틱 쓰레기의 양도 꾸준히 증가하고 있으며, 미세플라스틱은 해양 생물에 의해 섭취되어 소화관에 축적됨에 따라 성장과 생식에 유해한 영향을 미친다. Cytochrome P450 (CYP)는 환경 오염물질을 대사하 는 해독효소로 알려져 있으나 지각류에서는 그 기능에 대해서는 잘 알려져 있지 않다. 본 연 구에서는 기수산 물벼룩 Diaphanosoma celebensis에서 clan 2, 3, 4에 각각 속하는 CYP 유전자 9종(clan 2: CYP370A4, CYP370C5; clan 3: CYP350A1, CYP350C5, CYP361A1; clan 4: CYP4AN-like, CYP4AP2, CYP4AP3, CYP4C33-like1)의 서열에 대해 진화적으로 보존된 서열의 유사도를 분석 하고 계통분석을 실시하였다. 또한 3종류의 서로 다른 크기의 polystyrene beads (0.05-, 0.5-, 6-μm PS beads; 0.1, 1, and 10 mg/L)에 48시간 노출된 기수산 물벼룩에서 이들 9종의 CYP 유 전자의 발현을 real time reverse transcription polymerase chain reaction (RT-PCR)로 분석하였 다. 결과적으로 기수산 물벼룩 CYP 유전자는 모두 진화적으로 보존된 motif를 가지고 있으며 계통분석 결과 각각 clan 2, 3, 4에 속하는 것으로 확인되었다. 이는 기능적으로 보존되어 있음 을 의미한다. CYP 유전자 중 clan 2에 속하는 CYP370C5와 clan 3에 속하는 CYP360A1, 그리고 clan 4에서는 CYP4C122 유전자의 발현이 0.05-μm PS beads에 노출되었을 때 유의하게 증가 하는 양상을 보였으며, 이는 이들 유전자가 PS 대사에 관여한다는 것을 의미한다. 본 연구는 미세플라스틱이 해양 무척추 동물에 미치는 생물 영향을 분자적 수준에서 이해하는데 도움이 될 것이다.
        4,200원
        18.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Reliable, inexpensive, environment-friendly, and durable properties of carbon materials with unique and outstanding photoelectric performance is highly desired for myriad of applications such as catalysis and energy storage. Since lattice modulation is a vital method of surface modification of materials, which form by an external force during the synthesis process, causing the internal compression and stretching, leading to lattice sliding event. In this review, we present a summary of different methods to tailor the lattice modulation in 2D carbon-based materials, including grain/twin boundary, lattice strain, lattice distortion, and lattice defects. This overview highlights the implication control of the diverse morphologies of nanocrystals and how to tailor the materials properties without adding any polymers. The improvement in the performance of 2D carbon materials ranges from the enhancement of charge transport and conductivity, structural stability, high-performance of light absorption capacity, and efficient selectivity promote the future prospect of 2D carbon materials broaden their applications in terms of energy conversion and storage. Finally, some perspectives are proposed on the future developments and challenges on 2D carbon materials towards energy storage applications.
        4,200원
        20.
        2023.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        A Forbush decrease (FD) is a depression of cosmic ray (CR) intensity observed by ground-based neutron monitors (NMs). The CR intensity is thought to be modulated by the heliospheric magnetic structures including the interplanetary coronal mass ejection (ICME) surrounding the Earth. The different magnitude of the decreasing in intensity at each NM was explained only by the geomagnetic cutoff rigidity of the NM station. However, sometimes NMs of almost the same cutoff rigidity in northern and southern hemispheres observe the asymmetric intensity depression magnitudes of FD events. Thus, in this study we intend to see the effects on CR intensity modulation of FD event recorded at different NMs due to different ICME propagation directions as an additional parameter in the model explaining the CR modulation. Fortunately, since 2006 the coronagraphs of twin spacecraft of the STEREO mission allow us to infer the propagation direction of ICME associated with the FD event in 3-dimension with respect to the Earth. We suggest the hypothesis that the asymmetric CR modulations of FD events are determined by the propagation directions of the associated ICMEs.
        4,000원
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