• 제목/요약/키워드: Single molecules

검색결과 495건 처리시간 0.035초

Secondary Structure for RNA Aptamers Binding to Guanine-Rich Sequence in the 5'-UTR RNA of N-Ras Oncogene

  • Cho, Bongrae
    • 대한화학회지
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    • 제65권2호
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    • pp.121-124
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    • 2021
  • RNA molecules which bind to the G-rich sequence in the 5'-UTR RNA which plays an important role in expression of N-ras, were selected. The secondary structures of five selected RNA aptamers including primer sequence were found by the CLC RNA workbench ver. 4.2 program (www.clcbio.com) and investigated with RNA structural probes such as RNase T1 which has specificity for a G in single-stranded region, RNase V1 specific for double strand and nuclease S1 specific for single strand. The generalized secondary structure model was proposed and characterized. It was composed of a central long double strand region flanked by single strand region at both end sides. The double strand region had an internal single-strand region and bulges. The single strand loop in the right side was composed of four or five nucleotides.

The Single-Cell Revelation of Thermogenic Adipose Tissue

  • Qi, Yue;Hui, Xiaoyan Hannah
    • Molecules and Cells
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    • 제45권10호
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    • pp.673-684
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    • 2022
  • The past two decades have witnessed an upsurge in the appreciation of adipose tissue (AT) as an immunometabolic hub harbouring heterogeneous cell populations that collectively fine-tune systemic metabolic homeostasis. Technological advancements, especially single-cell transcriptomics, have offered an unprecedented opportunity for dissecting the sophisticated cellular networks and compositional dynamics underpinning AT remodelling. The "re-discovery" of functional brown adipose tissue dissipating heat energy in human adults has aroused tremendous interest in exploiting the mechanisms underpinning the engagement of AT thermogenesis for combating human obesity. In this review, we aim to summarise and evaluate the use of single-cell transcriptomics that contribute to a better appreciation of the cellular plasticity and intercellular crosstalk in thermogenic AT.

Production of Biological Active Single Chain Bovine LH and FSH

  • Min, K.S.;Kang, M.H.;Yoon, J.T.;Jin, H.J.;Seong, H.H.;Chang, Y.M.;Chung, H.J.;Oh, S.J.;Yun, S.G.;Chang, W.K.
    • Asian-Australasian Journal of Animal Sciences
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    • 제16권4호
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    • pp.498-503
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    • 2003
  • Luteinizing hormone as other glycoprotein hormones is characterized by a heterodimeric structure composed a common $\alpha$-subunit noncovalently linked to a specific $\beta$-subunit. The correct conformation of the heterodimer is important for efficient secretion, hormonal-specific post-translational modifications, receptor binding and signal transduction. To determine whether $\alpha$- and $\beta$- subunits can be synthesized as a single polypeptide chain (tethered-bLH and -bFSH) and also display biological activities, the tetheredbLH and -bFSH molecules were constructed and transfected into chinese hamster ovary (CHO-K1) cells. LH and FSH activities were assayed by using the human embryonic kidney (HEK) 293 cells expressing rat LH and FSH receptor genes. The tethered-bLH and - bFSH proteins were efficiently secreted and showed a similar activity to the dimeric bovine LH and FSH $\alpha$/$\beta$ wild type and native purified from bovine pituitary. The tethered-molecules can be permit development of potent new analogues that stimulate ovarian development. Taken together, a single-chain analog can also be constructed to include additional hormone-specific bioactive generating potentially efficacious compounds. These data indicate the potentiality of the single chain approach to further investigate structurefunction relationships of LH and FSH.

사이크로덱스트린과 부탄산의 복합체 형성반응에 의한 초음파 완화 (Ultrasonic Relaxation for Complexation Reaction Between β-Cyclodextrin and Butanoic Acid in Aqueous Solution)

  • 배종림
    • 한국음향학회지
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    • 제31권2호
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    • pp.100-106
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    • 2012
  • The aim of this work was to reveal the effect of butanoic acid in its dissociated form and undissociated form as a guest molecule on the kinetic parameters in an inclusion reaction with ${\beta}$-cyclodextrin (${\beta}$-CD). Ultrasonic absorption measurements in the frequency range from 0.2 to 45 MHz were carried out for ${\beta}$-CD solutions with butanoic acid at $25^{\circ}C$ by ultrasonic relaxation method. The rate and the equilibrium constants were obtained from the guest concentration dependence of the relaxation frequency, and the standard volume change of the complexation reaction were obtained from the maximum absorption per wavelength. A single relaxational absorption was observed, and the cause of the relaxation was attributed to a perturbation of the chemical equilibrium associated with a complexation reaction between ${\beta}$-CD and butanoic acid. These results were compared with those in solutions containing both ${\beta}$-CD and different guest molecules. It was found that the hydrophobicity of guest molecules played an important role in the formation of the inclusion complex and also that the charge on the carboxylic group had a considerable effect on the kinetic characteristics of the complexation reaction.

Raman spectroscopy study on the reactions of UV-generated oxygen atoms with single-layer graphene on SiO2/Si substrates

  • Ahn, Gwang-Hyun;Kim, Hye-Ri;Hong, Byung-Hee;Ryu, Sun-Min
    • Carbon letters
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    • 제13권1호
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    • pp.34-38
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    • 2012
  • Successful application of graphene requires development of various tools for its chemical modification. In this paper, we present a Raman spectroscopic investigation of the effects of UV light on single layer graphene with and without the presence of $O_2$ molecules. The UV emission from a low pressure Hg lamp photolyzes $O_2$ molecules into O atoms, which are known to form epoxy on the basal plane of graphene. The resulting surface epoxy groups were identified by the disorder-related Raman D band. It was also found that adhesive residues present in the graphene samples prepared by micro-mechanical exfoliation using adhesive tape severely interfere with the O atom reaction with graphene. The UV-induced reaction was also successfully applied to chemical vapor deposition-grown graphene. Since the current method can be readily carried out in ambient air only with UV light, it will be useful in modifying the surfaces of graphene and related materials.

Enhancing Performance of 1-aminopyrene Light-Emitting Diodes via Hybridization with ZnO Quantum Dots

  • Choi, Jong Hyun;Kim, Hong Hee;Choi, Won Kook
    • 센서학회지
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    • 제31권4호
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    • pp.238-243
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    • 2022
  • In this study, a pyrene-core single molecule with amino (-NH2) functional group material was hybridized using ZnO quantum dots (QDs). The suppressed performance of the 1-aminopyrene (1-PyNH2) single molecule as an emissive layer (EML) in light-emitting diodes (LEDs) was exploited by adopting the ZnO@1-PyNH2 core-shell structure. Unlike pristine 1-PyNH2 molecules, the ZnO@1-PyNH2 hybrid QDs formed energy proximity levels that enabled charge transfer. This result can be interpreted as an improvement in surface roughness. The uniform and homogeneous EML alleviates dark-spot degradation. Moreover, LEDs with the ITO/PEDOT:PSS/TFB/EML/TPBi/LiF/Al configuration were fabricated to evaluate the performance of two emissive materials, where pristine-1-PyNH2 molecules and ZnO@1-PyNH2 QDs were used as the EML materials to verify the improvement in electrical characteristics. The ZnO@1-PyNH2 LEDs exhibited blue luminescence at 443 nm (FWHM = 49 nm), with a turn-on voltage of 4 V, maximum luminance of 1500 cd/m2, maximum luminous efficiency of 0.66 cd/A, and power efficiency of 0.41 lm/W.

A review on gold nanowire based SERS sensors for chemicals and biological molecules

  • Rashida Akter;Hyuck Jin Lee;Toeun Kim;Jin Woo Choi;Hongki Kim
    • 분석과학
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    • 제37권4호
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    • pp.201-210
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    • 2024
  • Surface-enhanced Raman scattering (SERS) has emerged as a powerful technique for detecting and analyzing chemical and biological molecules at ultra-low concentrations. The effectiveness of SERS largely depends on structures with sub-10 nm gaps, prompting the proposal of various nanostructures as efficient SERS-active platforms. Among these, single-crystalline gold nanowires (AuNWs) are particularly promising due to their large dielectric constants, well-defined geometries, atomically smooth surfaces, and surface plasmon resonance across the visible spectrum, which produce strong SERS enhancements. This review comprehensively explores the synthesis, functionalization, and application of Au NWs in SERS. We discuss various methods for synthesizing AuNWs, including the vapor transport method, which influences their morphological and optical properties. We also review practical applications in chemical and biosensing, showcasing the adaptability of Au NWs-based SERS platforms in detecting a range of analytes, from environmental pollutants to biological markers. The review concludes with a discussion on future perspectives that aim to enhance sensor performance and broaden application domains, highlighting the potential of these sensors to revolutionize diagnostics and environmental monitoring. This review underscores the transformative impact of AuNW-based SERS sensors in analytical chemistry, environmental science, and biomedical diagnostics, paving the way for next-generation sensing technologies.

Fabrication of a Single Molecule Detection System and Its Application: Connection between Ensemble and Single Molecule Measurements

  • Park, Mira;Lee, Heung Soon;Kim, DongHo;Song, Nam Woong
    • Journal of Photoscience
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    • 제11권2호
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    • pp.47-53
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    • 2004
  • A laser scanning fluorescence microscope system has been fabricated for single molecule detection (SMD). Problems associated with the system set-up have been discussed along with proper suggestions. Based on the SMD results obtained by using the apparatus, a statistical method has been suggested to determine the minimum number of required molecules to form a group of uniform average in a selected error range.

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