Fluorenyl Based Macrocyclic Polyradicaloids

Lu, Xuefeng,Lee, Sangsu,Hong, Yongseok,Phan, Hoa,Gopalakrishna, Tullimilli Y.,Herng, Tun Seng,Tanaka, Takayuki,Sandoval-Salinas, Marí,a Eugenia,Zeng, Wangdong,Ding, Jun,Casanova, David,Osuka, At American Chemical Society 2017 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.139 No.37

<P>Synthesis of stable open-shell polyradicaloids including control of intramolecular spin-spin interactions is a challenging topic in organic chemistry and materials science. Herein, we report the synthesis and physical characterization of two series of fluorenyl based macrocyclic polyradicaloids. In one series (FR-MCn, n = 4-6), the fluorenyl radicals are directly linked at 3,6-positions; whereas in the other series (MC-FnAn, n = 3-5), an additional ethynylene moiety is inserted between the neighboring fluorenyl units. To access stable macrocyclic polyradicaloids, three synthetic methods were developed. All of these stable macrocycles can be purified by normal silica gel column chromatography under ambient conditions. In all cases, moderate polyradical characters were calculated by restricted active space spin-flip method due to the moderate intramolecular antiferromagnetic spin-spin interactions. The excitation energies from the low-spin ground state to the lowest high-spin excited state were evaluated by superconducting quantum interference device measurements. Their physical properties were also compared with the respective linear fluorenyl radical oligomers (FR-n, n = 3-6). It is found that the geometry, i.e., the distortional angle and spacer (w or w/o ethynylene) between the neighboring fluorenyl units, has significant effect on their polyradical character, excitation energy, one-photon absorption, two-photon absorption and electrochemical properties. In addition, the macrocyclic tetramers FR-MC4 and MC-F4A4 showed global antiaromatic character due to cyclic pi-conjugation with 36 and 44 pi-electrons, respectively.</P>

Electrochemical Pigment Coloring of Wool Fabrics

Genyang Cao,Xuefeng Lu,Weilin Xu,Xin Wang 한국섬유공학회 2018 Fibers and polymers Vol.19 No.1

Green processing technology has been examined extensively in the area of textile coloring, because it is usually highly efficient, environmentally friendly, and energy conserving. Herein, a novel pigment coloring technology by electrochemical modification of wool fabric surfaces is reported. This technology exhibits superior color properties with higher efficiency and lower energy and chemical consumption than the conventional cationic pretreatment coloring method. The pigment-colored wool fabric was characterized to investigate its surface morphology and roughness, K/S value, and rubbing fastness (dry and wet) under a variety of experimental conditions. The mechanism of electrochemical pigment coloring technology has been revealed, and the color properties of the fabrics have been fully investigated. Optimized technological parameters, including voltage, coloring time, and electrolyte concentration, have been determined for further application of this promising technology. Electrochemical pigment coloring has great potential for commercialization as it results in superior color performance with less pollution, higher efficiency, and lower input consumption compared with other methods.

Core–shell structure g-MnO2-PANI carbon fiber paper-based flexible electrode material for high-performance supercapacitors

Xuxia Ling,Guoliang Zhang,Zhu Long,Xuefeng Lu,Zhibin He,Jie Li,Yuheng Wang,Dan Zhang 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.99 No.-

Good conductivity is the key to ensuring high electrochemical performance, and the uniformity of theactive material directly affects the electrical conductivity. This paper proposes a novel modified stepwisein situ polymerization method to prepare composite materials, and then uses the K/S value method tocharacterize the uniformity of polyaniline distribution. Specifically, the study presents a papermakingwet-lay technique to prepare a carbonfiber paper substrate (CP) that is light-weight,flexible, andfoldable while also having low internal resistance and high porosity. The g-MnO2 is wrapped with PANI toform a core–shell structure, and a modified stepwise in situ polymerization method is adopted to depositthe core–shell structure uniformly on the CP substrate by physical adsorption. This process yields aflexible electrode material for supercapacitors, called g-MnO2-PANI-CP electrode. Results show thatthe g-MnO2-PANI-CP electrode has a high specific capacitance of 642.5 F g 1 at a current density of 1A g 1, and also has a high energy density of 114.2 Wh kg 1 at a power density of 798.6 W kg 1. In addition,the electrode retains 81.3% of the initial capacitance after 5000 cycles, demonstrating high cyclingperformance.

Circ_0000554 is identified as a cancer‑promoting circRNA in colorectal cancer by regulating the miR‑1205/LASP1 axis

Luo Jinlong,Yang Hua,Peng Xuefeng,Zhang Faqiang,Shu Shilong,Lan Ke,Tu Shengjin,Lu Kai,Cha Xiaoying 한국응용생명화학회 2022 Applied Biological Chemistry (Appl Biol Chem) Vol.65 No.5

Background: Colorectal cancer (CRC) is a prevalent malignant tumor with poor prognosis. Circular RNAs (circRNAs) are key regulators in the progression of CRC. Our study aimed to disclose the role of circ_0000554 in CRC. Methods: The expression of circ_0000554, miR-1205 and LIM and SH3 protein 1 (LASP1) was measured by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation, invasion and migration were monitored using cell counting kit-8 (CCK-8) assay, EdU assay, transwell assay and wound healing assay respectively. The protein levels of C-myc, matrix metallopeptidase 2 (MMP-2) and LASP1 were detected by western blot. Tumor formation assay in nude mice was conducted to explore the role of circ_0000554 in vivo. The association between miR-1205 and circ_0000554 or LASP1 was identified by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Results: circ_0000554 was upregulated in CRC tissues and cells, high circ_0000554 expression was significantly linked to shorter overall survival. Downregulation of circ_0000554 restrained cell growth and metastasis while promoted apoptosis in vitro, and suppressed tumorigenesis of CRC in vivo. Furthermore, mechanism study and rescue experiments confirmed miR-1205 could be sponged by circ_0000554 and its inhibitor reversed the inhibitory effect of circ_0000554 silencing on CRC progression. LASP1 was a target gene of miR-1205 and the upregulation of LASP1 overturned miR-1205-induced effects on CRC cells. Circ_0000554 could elevate LASP1 expression via interacting with miR-1205.

Shear-strain induced structural relaxation of Cu Σ3 [110](112) symmetric tilt grain boundary: The role of foreign atoms and temperature

Li Yang,Xue Hongtao,Zhou Xin,Tang Fuling,Li Xiuyan,Ren Junqiang,Lu Xuefeng 한국물리학회 2021 Current Applied Physics Vol.28 No.-

Grain boundaries (GBs) relaxation is a promising and effective strategy to improving GB stability or stabilizing nanocrystalline metals. However, previous studies mainly focused on nanocrystalline pure metals and GB behaviors therein, without considering the role of foreign atoms such as impurity or alloying atoms in GB relaxation. In this work, the shear-strain induced structural relaxation of pure Cu Σ3 [110](112) symmetric tilt GBs (STGBs), and the effects of foreign elements (Fe and Ni) and temperature on the GB relaxation were investigated in detail by molecular dynamics method. The results show that shear strain can trigger the structural relaxation of pure, Fe- and Ni-containing Cu GBs by the emission of Shockley partial dislocations from Cu GBs. Both Fe and Ni have impediment effects on the shear-strain induced GB relaxation, though the content of Fe or Ni atom (0.00165 at.%) is quite low in the GB model. The temperature cannot trigger GB relaxation independently within the considered temperature range, but play a positive role in the shear-strain induced structural relaxations of pure, Fe- and Ni-containing Cu Σ3 [110](112) STGBs. Our work might gain new insights into the mechanically induced GB relaxation in nanocrystalline copper and could be beneficial for improving the stability of Cu GBs.

Identification of DNA methylation and genetic alteration simultaneously from a single blood biopsy

Chen Xiaomin,Liu Jiahui,Li Jun,Xie Yinpeng,Yu Zichen,Shen Lu,Liu Qingfeng,Wu Wei,Zhao Qiang,Lin Haoxiang,Liu Gaotong,Luo Qiuping,Yang Ling,Huang Yi,Zhao Meiru,Yi Xin,Xia Xuefeng 한국유전학회 2023 Genes & Genomics Vol.45 No.5

Background High-throughput sequencing of blood cell-free DNA (cfDNA) techniques offer an opportunity to characterize and monitor cancer rapidly in a non-invasive and real-time manner. Nonetheless, there lacks a tool within therapeutic arsenal to identify multi-omics alterations simultaneously from a single biopsy. In current times, bisulfite-based sequencing detects 5mC and 5hmC at single-base resolution is the golden standard of DNA methylation, while the degradation of DNA and biased sequencing data are the problems of this method. Objective To identify the consistency analysis of methylation and genetic variation with single library, we presented a platform detecting multi-omics data simultaneously from a single blood biopsy using bisulfite-free method of genomic methylation sequencing (GM-seq) mediated by TET enzyme. Methods We detected methylomic and genetic changes simultaneously from a single blood biopsy in NA12878 and randomly chose ten blood biopsies from colorectal cancer or lung cancer patients to validate the ability of GM-seq. Results Similar cytosine methylation level between whole genome bisulfite sequencing (WGBS) and GM-seq were identified in NA12878. Moreover, longer insert size, CpGs coverage and GC distribution were outperformed than WGBS. In addition, the comparison of the single nucleotide polymorphism (SNP), insertion-deletion (Indel) and copy number variation (CNV) in NA12878 or ctDNA from liver cancer between GM-seq and whole genome sequencing (WGS) show a good consistency, indicating that this method is feasible for detecting genetic variation in blood. Conclusion In conclusion, our work demonstrated a method for identification of the methylated modification and genetic variations simultaneously from a single blood biopsy.

Effect of Annealing Temperature on the Microstructure and Tensile Properties of a Bimodal Nano/Micro Grained 1020 Carbon Steel Prepared by Aluminothermic Reaction Casting

Peiqing La,Xin Guo,Hongding Wang,Ting Shi,Xiaojuan Zhen,Fuan Wei,Xuefeng Lu 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.2

Bulk 1020 carbon steel was prepared by aluminothermic reaction casting. After casting, isothermal aging treatments at different temperatures are performed for different periods up to 8 h. Microstructure characterization was performed using many methods, including optical microscopy, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. It was found that the steel consisted of a nanocrystalline- ferrite matrix and a microcrystalline pearlite phase with a laminar structure. The average grain sizes of the ferrite were 23, 24, 28, and 37 nm for the cast steel and for samples annealed at 600, 800, and 1000 °C, respectively. As the annealing temperature increased, the volume fraction of the pearlite initially increased and then decreased, while the laminar spacing of pearlite increased from 240 to 900 nm. When annealed at 1000 °C, a spherical black micron pearlite particle was formed. The tensile and yield strength dramatically decreased, and the elongation varied slightly with the annealing temperature. A ductile phase was achieved by extending the holding time.

Single-Atom Switches and Single-Atom Gaps Using Stretched Metal Nanowires

Wang, Qingling,Liu, Ran,Xiang, Dong,Sun, Mingyu,Zhao, Zhikai,Sun, Lu,Mei, Tingting,Wu, Pengfei,Liu, Haitao,Guo, Xuefeng,Li, Zong-Liang,Lee, Takhee American Chemical Society 2016 ACS NANO Vol.10 No.10

<P>Utilizing individual atoms or molecules as functional units in electronic circuits meets the increasing technical demands for the miniaturization of traditional semiconductor devices. To be of technological interest, these functional devices should be high-yield, consume low amounts of energy, and operate at room temperature. In this study, we developed nanodevices called quantized conductance atomic switches (QCAS) that satisfy these requirements. The QCAS operates by applying a feedback-controlled voltage to a nanoconstriction within a stretched nanowire. We demonstrated that individual metal atoms could be removed from the nanoconstriction and that the removed metal atoms could be refilled into the nanoconstriction, thus yielding a reversible quantized conductance switch. We determined the key parameters for the QCAS between the 'on' and 'off' states at room temperature under a small operating voltage. By controlling the applied bias voltage, the atoms can be further completely removed from the constriction to break the nanowire, generating single-atom nanogaps. These atomic nanogaps are quite stable under a sweeping voltage and can be readjusted with subangstrom accuracy, thus fulfilling the requirement of both reliability and flexibility for the high-yield fabrication of molecular devices.</P>

Enhancing Performances of Polyamide 66 Short Fiber/Natural Rubber Composites via In Situ Vulcanization Reaction

Zhi Hao,Junqi Shen,Xiang Sheng,Zong Shen,Le Yang,Xuefeng Lu,Zhu Luo,Qiang Zheng 한국섬유공학회 2020 Fibers and polymers Vol.21 No.2

This paper details a new method for improving the interfacial bonding between PA66 short fiber (PSF) and natural rubber (NR) by reaction of the methacrylic acid (MAA)-grafting-modified PSF with rubber during vulcanization. Carboncarbon double bonds introduced to the SF surface by MAA grafting were opened, and a vulcanization reaction occurred between the modified PSF and rubber in the presence of sulfur. The chemical reactions were verified by FTIR and XPS. The processing rheological behaviors of the compounded composites were investigated by a rubber processing analyzer (RPA). The morphology of modified PSF was characterized by AFM and SEM. The improved interfacial bonding was confirmed by DMA, which enhanced deformational stress at definite elongation of the NR/PSF composites. The volume concentration of the MAA solution for grafting on the SF surface had a great influence on the interfacial bonding and mechanical properties of the composites; when the volume concentration was 30 %, the modified PSF-reinforced NR/CB had the best interfacial bonding and mechanical properties.

Stable 2D anti-ferromagnetically coupled fluorenyl radical dendrons

Wang, Jian,Kim, Gakhyun,Sandoval-Salinas, Marí,a Eugenia,Phan, Hoa,Gopalakrishna, Tullimilli Y.,Lu, Xuefeng,Casanova, David,Kim, Dongho,Wu, Jishan Royal Society of Chemistry 2018 Chemical Science Vol.9 No.13

<▼1><P>The first class of stable two-dimensional anti-ferromagnetically coupled dendritic polyradicaloids was synthesized, which show polyradical character and unique properties.</P></▼1><▼2><P>We report the first class of stable, two-dimensional (2D) anti-ferromagnetically coupled dendritic polyradicaloids. A kinetically blocked fluorenyl radical was used to build up the first and second generation dendrons <B>FR-G1</B> and <B>FR-G2</B> containing three and seven fluorenyl units, respectively. The neighboring fluorenyl radicals in <B>FR-G1</B> and <B>FR-G2</B> show moderate anti-ferromagnetic exchange interaction, resulting in a doublet and quartet ground state, respectively, with a small doublet–quartet energy gap. From <B>FR-G1</B> to <B>FR-G2</B>, the energy gap decreased and the two-photon absorption was enhanced owing to more extended 2D π-conjugation. Both compounds showed multiple redox waves due to their polyradical character.</P></▼2>