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| 2. |
- Wang, Siqi, et al.
(author)
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Adjusting Competitive Reaction to Control Nucleation and Growth of MnO2 for a High-Stress Output Electrochemical Actuator
- 2023
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In: ACS APPLIED ELECTRONIC MATERIALS. - : AMER CHEMICAL SOC. - 2637-6113. ; 5:9, s. 4836-4845
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Journal article (peer-reviewed)abstract
- Manganese dioxide (MnO2) with biocompatibility has promising applications in low-voltage electrochemical actuators of implantable medical devices, which can convert electrical energy to mechanical motion. However, the unsatisfactory actuation strain restricts the generation of a larger output stress of MnO2 for practical application. Herein, a competitive reaction-driven-MnO2 (CRD-MnO2) nanorod network was fabricated on a nickel (Ni) thin-film substrate by adjusting the component molar ratios. We find that the competitive reaction between 3,4-ethylene-dioxythiophene (EDOT) polymerization and oxidation of Mn2+ controls the nucleation and growth behavior of MnO2. The variation in the electron environment, newly generated oxygen vacancies, and a higher content of structural water effectively improve the electroactivity of MnO2 and simultaneously cause more serious Jahn-Teller (JT) distortion of the crystal octahedrons. Thus, an excellent output performance simultaneously having a much higher actuating strain of 8.3% and an actuation stress of 390.1 MPa is generated during a redox reaction between Mn4+ and Mn3+ under 0-1 V. Moreover, the CRD-MnO2/Ni composite actuating films assembled on a 3D-printed resin model of a human hand with separated finger joints can perform smooth grasping and releasing actions, demonstrating a huge potential for in vitro rehabilitation exercises and implantability for people with finger dyskinesia. This work provides a strategy for actuator material fabrication by controlling a nucleation and growth process by adjusting a competitive reaction.
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| 3. |
- Wang, Yong, et al.
(author)
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mRNA expression of minichromosome maintenance 2 in colonic adenoma and adenocarcinoma
- 2009
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In: EUROPEAN JOURNAL OF CANCER PREVENTION. - 0959-8278. ; 18:1, s. 40-45
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Journal article (peer-reviewed)abstract
- As proliferation is essential for Progression from normal cells to tumor, certain markers specific to proliferating cells may permit detection of premalignant lesions. Here, we aimed to evaluate the possible value of a proliferation marker, minichromosome maintenance 2 (MCM2), in the early diagnosis of colorectal cancer, by analyzing the difference in MCM2 expression among normal mucosa, adenoma, and adenocarcinoma, and investigating the relationship of MCM2 expression in adenomas with clinicopathologic variables. Using immunohistochemistry and real-time reverse transcription-PCR, we observed that the expression of MCM2 protein was present on basal third to half of colonic crypts in normal mucosa, whereas throughout the epithelium in adenomas and adenocarcinomas, the expression of MCM2 mRNA in adenocarcinomas was significantly higher than in adenomas (P=0.001), whereas the difference between adenoma and normal mucosa was not significant (P=0.184); we also found that the expression of MCM2 mRNA tended to be increased in the adenomas with high-grade dysplasia, or in older patients, respectively, compared with those with low-grade dysplasia, and younger patients. These results suggested the potential value of MCM2 in early diagnosis of colorectal cancer.
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| 5. |
- Meng, Wen-Jian, et al.
(author)
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Correlation of SATB1 overexpression with the progression of human rectal cancer
- 2012
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In: International Journal of Colorectal Disease. - : Springer Verlag (Germany). - 0179-1958 .- 1432-1262. ; 27:2, s. 143-150
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Journal article (peer-reviewed)abstract
- To date, the association between special AT-rich sequence-binding protein 1 (SATB1) and colorectal cancer (CRC) has not been reported. This study was aimed at investigating the expression and potential role of SATB1 in human rectal cancers. less thanbrgreater than less thanbrgreater thanNinety-three paired samples of rectal cancer and distant normal rectal tissue were analyzed by quantitative real-time PCR (qRT-PCR) and immunohistochemistry (IHC), and the correlations between SATB1 expression and clinicopathological parameters were evaluated. The expression profiles of SATB1 were also investigated in a panel of five human colon carcinoma cell lines. less thanbrgreater than less thanbrgreater thanThe general level of SATB1 mRNA in rectal cancer tissues was statistically significantly higher than that in normal mucosa (P = 0.043). The rate of positive SATB1 protein expression in rectal cancers (44.1%) was significantly higher than that in normal tissues (25.8%) by IHC analysis (P = 0.009). Overexpression of SATB1 mRNA was more predominant in patients with earlier onset of rectal cancer (P = 0.033). SATB1 expression correlated with invasive depth and tumor node metastasis (TNM) stage at both protein and mRNA levels (P andlt; 0.05). Furthermore, SATB1 expression in the poorly metastatic KM12C cells was significantly lower than the highly metastatic KM12SM and KM12L4A cells and higher than the HCT116 and SW480 cells (P = 0.001). These results were further confirmed by Western blotting. less thanbrgreater than less thanbrgreater thanOur results indicate that SATB1 may play an important role in the progression of human rectal cancer, which represents a possible new mechanism underlying CRC.
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| 6. |
- Neupane, Madhab, et al.
(author)
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Observation of quantum-tunnelling-modulated spin texture in ultrathin topological insulator Bi2Se3 films.
- 2014
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 5
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Journal article (peer-reviewed)abstract
- Understanding the spin-texture behaviour of boundary modes in ultrathin topological insulator films is critically essential for the design and fabrication of functional nanodevices. Here, by using spin-resolved photoemission spectroscopy with p-polarized light in topological insulator Bi2Se3 thin films, we report tunnelling-dependent evolution of spin configuration in topological insulator thin films across the metal-to-insulator transition. We report a systematic binding energy- and wavevector-dependent spin polarization for the topological surface electrons in the ultrathin gapped-Dirac-cone limit. The polarization decreases significantly with enhanced tunnelling realized systematically in thin insulating films, whereas magnitude of the polarization saturates to the bulk limit faster at larger wavevectors in thicker metallic films. We present a theoretical model that captures this delicate relationship between quantum tunnelling and Fermi surface spin polarization. Our high-resolution spin-based spectroscopic results suggest that the polarization current can be tuned to zero in thin insulating films forming the basis for a future spin-switch nanodevice.
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| 7. |
- Zhang, Rong guang, et al.
(author)
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Structure of Escherichia coli ribose-5-phosphate isomerase : a ubiquitous enzyme of the pentose phosphate pathway and the Calvin cycle
- 2003
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In: Structure. - 0969-2126 .- 1878-4186. ; 11:1, s. 31-42
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Journal article (peer-reviewed)abstract
- Ribose-5-phosphate isomerase A (RpiA; EC 5.3.1.6) interconverts ribose-5-phosphate and ribulose-5-phosphate. This enzyme plays essential roles in carbohydrate anabolism and catabolism; it is ubiquitous and highly conserved. The structure of RpiA from Escherichia coli was solved by multiwavelength anomalous diffraction (MAD) phasing, and refined to 1.5 A resolution (R factor 22.4%, R(free) 23.7%). RpiA exhibits an alpha/beta/(alpha/beta)/beta/alpha fold, some portions of which are similar to proteins of the alcohol dehydrogenase family. The two subunits of the dimer in the asymmetric unit have different conformations, representing the opening/closing of a cleft. Active site residues were identified in the cleft using sequence conservation, as well as the structure of a complex with the inhibitor arabinose-5-phosphate at 1.25 A resolution. A mechanism for acid-base catalysis is proposed.
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| 9. |
- Zhang, Rong-Guang, et al.
(author)
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The 2.2 A resolution structure of RpiB/AlsB from Escherichia coli illustrates a new approach to the ribose-5-phosphate isomerase reaction
- 2003
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In: Journal of Molecular Biology. - : Elsevier BV. - 0022-2836 .- 1089-8638. ; 332:5
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Journal article (peer-reviewed)abstract
- Ribose-5-phosphate isomerases (EC 5.3.1.6) interconvert ribose 5-phosphate and ribulose 5-phosphate. This reaction permits the synthesis of ribose from other sugars, as well as the recycling of sugars from nucleotide breakdown. Two unrelated types of enzyme can catalyze the reaction. The most common, RpiA, is present in almost all organisms (including Escherichia coli), and is highly conserved. The second type, RpiB, is present in some bacterial and eukaryotic species and is well conserved. In E.coli, RpiB is sometimes referred to as AlsB, because it can take part in the metabolism of the rare sugar, allose, as well as the much more common ribose sugars. We report here the structure of RpiB/AlsB from E.coli, solved by multi-wavelength anomalous diffraction (MAD) phasing, and refined to 2.2A resolution. RpiB is the first structure to be solved from pfam02502 (the RpiB/LacAB family). It exhibits a Rossmann-type alphabetaalpha-sandwich fold that is common to many nucleotide-binding proteins, as well as other proteins with different functions. This structure is quite distinct from that of the previously solved RpiA; although both are, to some extent, based on the Rossmann fold, their tertiary and quaternary structures are very different. The four molecules in the RpiB asymmetric unit represent a dimer of dimers. Active-site residues were identified at the interface between the subunits, such that each active site has contributions from both subunits. Kinetic studies indicate that RpiB is nearly as efficient as RpiA, despite its completely different catalytic machinery. The sequence and structural results further suggest that the two homologous components of LacAB (galactose-6-phosphate isomerase) will compose a bi-functional enzyme; the second activity is unknown.
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