50 results on '"Guo FS"'
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2. Macrocarpal B blocks the binding between the phospholipase A2 receptor and its antibodies.
- Author
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Feng Z, Guo FS, Wang Q, Wang M, Zhao MH, Cui Z, and Lei X
- Subjects
- Humans, Podocytes metabolism, Podocytes drug effects, Dose-Response Relationship, Drug, Molecular Structure, Structure-Activity Relationship, Glomerulonephritis, Membranous drug therapy, Glomerulonephritis, Membranous immunology, Glomerulonephritis, Membranous metabolism, Immunoglobulin G metabolism, Immunoglobulin G immunology, Immunoglobulin G chemistry, Protein Binding, Small Molecule Libraries chemistry, Small Molecule Libraries pharmacology, Receptors, Phospholipase A2 immunology, Receptors, Phospholipase A2 antagonists & inhibitors, Receptors, Phospholipase A2 metabolism, Receptors, Phospholipase A2 chemistry
- Abstract
The pathogenic role of anti-phospholipase A2 receptor (PLA2R) antibodies in primary membranous nephropathy (MN) has been well-established. This study aimed to identify potential small-molecule inhibitors against the PLA2R-antibody interaction, offering potential therapeutic benefits. A comprehensive screening of over 4000 small-molecule compounds was conducted by ELISA to assess their inhibitory effects on the binding between the immobilized full-length extracellular PLA2R and its antibodies. The affinity of anti-PLA2R IgG from MN patients and the inhibitory efficacy of each compound were evaluated via surface plasmon resonance (SPR). Human podocyte injuries were analyzed using CCK-8 assay, wound healing assay, western blot analysis, and immunofluorescence, after exposure to MN plasma +/- blocking compound. Fifteen compounds were identified as potential inhibitors, demonstrating inhibition rates >20 % for the PLA2R-antibody interaction. Anti-PLA2R IgG exhibited a consistent affinity among patients (K
D = 10-8 M). Macrocarpal B emerged as the most potent inhibitor, reducing the antigen-antibody interaction by nearly 30 % in a dose-dependent manner, comparable to the performance of the 31-mer peptide from the CysR domain. Macrocarpal B bound to the immobilized PLA2R with an affinity of 1.47 × 10-6 M, while showing no binding to anti-PLA2R IgG. Human podocytes exposed to MN plasma showed decreased podocin expression, impaired migration function, and reduced cell viability. Macrocarpal B inhibited the binding of anti-PLA2R IgG to podocytes and reduced the cellular injuries., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: The author is an Editorial Board Member/Editor-in-Chief/Associate Editor/Guest Editor for [Bioorganic & Medicinal Chemistry] and was not involved in the editorial review or the decision to publish this article., (Copyright © 2024 Elsevier Ltd. All rights reserved.)- Published
- 2024
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3. Impact of the COVID-19 pandemic on cardiovascular mortality and contrast analysis within subgroups.
- Author
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Song S, Guo C, Wu R, Zhao H, Li Q, Dou JH, Guo FS, and Wei J
- Abstract
Background: An increase in deaths has been perceived during the pandemic, which cannot be explained only by COVID-19. The actual number of deaths far exceeds the recorded data on deaths directly related to SARS-CoV-2 infection. Data from early and short-lived pandemic studies show a dramatic shift in cardiovascular mortality. Grounded in the post-pandemic era, macroscopic big data on cardiovascular mortality during the pandemic need to be further reviewed and studied, which is crucial for cardiovascular disease prevention and control., Methods: We retrieved and collected data associated with cardiovascular disease mortality from the National Vital Statistic System from the Center for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research (CDC WONDER) platform based on the ICD-10 codes. We applied regression analysis to characterize overall cardiovascular disease mortality trends from 2010 to 2023 and built a time series model to predict mortality for 2020-2023 based on mortality data from 2010 to 2019 in order to affirm the existence of the excess deaths by evaluating observed vs. predicted mortality. We also conducted subgroup analyses by sex, age and race/ethnicity for the purpose of obtaining more specific sociodemographic information., Results: All-cause age-standardised mortality rates (ASMRs) for CVD dramatically increased between 2019 and 2021[annual percentage change (APC) 11.27%, p < 0.01], and then decreased in the following 2021-2023(APC: -7.0%, p < 0.01). Subgroup analyses found that the ASMR change was most pronounced in Alaska Indians/Native American people (APC: 16.5% in 2019-2021, -12.5% in 2021-2023, both p < 0.01), Hispanics (APC: 12.1% in 2019-2021, -12.2% in 2021-2023, both p < 0.05) and non-Hispanic Black people (APC:11.8% in 2019-2021, -10.3% in 2021-2023, both p < 0.01)whether during the increasing or declining phase. Similarly, the ASMR change was particularly dramatic for the 25-44 age group (APC:19.8% in 2019-2021, -15.4% in 2021-2023, both p < 0.01) and males (APC: 11.5% in 2019-2021, -7.6% in 2021-2023, both p < 0.01). By the end of 2023, the proportion of COVID-related excess death remained high among the elderly (22.4%), males (42.8%) and Alaska Indians/Native American people(39.7%). In addition, we did not find the presence of excess deaths in the young (25-44) and middle-aged cohort (45-64) in 2023, while excess deaths remained persistent in the elderly., Conclusions: All-cause ASMRs for CVD increased notably during the initial two years of the COVID-19 pandemic and then witnessed a decline in 2021-2023. The cohorts (the young, males and minorities) with the steepest rise in mortality decreased at the fastest rate instead. Previous initiatives to promote cardiovascular health were effective, but further research on cardiovascular healthcare for the elderly and racial disparities should be attached to priority considering the presence of sociodemographic differences in CVD death., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2024 Song, Guo, Wu, Zhao, Li, Dou, Guo and Wei.)
- Published
- 2024
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4. Mitophagy-dependent cardioprotection of resistance training on heart failure.
- Author
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Guo C, Wu RY, Dou JH, Song SF, Sun XL, Hu YW, Guo FS, Wei J, Lin L, and Wei J
- Subjects
- Humans, Mice, Animals, Mitophagy, Myocytes, Cardiac metabolism, Ubiquitin-Protein Ligases metabolism, Resistance Training, Heart Failure
- Abstract
Resistance exercise is an indispensable mode of exercise rehabilitation for heart failure. Here we elucidate the cardiac effects of resistance training alone or combined with different aerobic trainings on heart failure and explore the critical regulation of mitophagy. The chronic heart failure model was constructed by transverse aortic constriction surgery, followed by 8 wk of resistance training (RT), moderate-intensity continuous training combined with resistance training (MRT), and high-intensity interval training combined with resistance training (HRT), and subsequently analyzed the changes of maximum load, cardiac structure and function, and myocardial mitophagic activity. The role and signaling of mitophagy in exercise protection of heart failure were investigated by knockdown of Hif1α and Parkin genes in primary neonatal cardiomyocytes. RT and especially MRT improved maximum load ( P < 0.0001), myocardial morphology and fibrosis ( P < 0.0001), reduced left ventricular diameter and enhanced left ventricular systolic function ( P < 0.01), and enhanced myocardial mitophagic activity and HIF1α expression ( P < 0.05) in heart failure mice. However, HRT had no obvious protective effect on ventricular diameter and function or mitophagy. The abilities of exercise stimulation to regulate reactive oxygen species, adenosine triphosphate, and brain natriuretic peptide were impaired after knockdown of Hif1α and Parkin genes inhibited mitophagy in failing cardiomyocytes ( P < 0.05). Different exercise modalities provide discrepant cardiovascular effects on heart failure, and MRT exhibits optimal protection. The HIF1α-Parkin-mitophagy pathway is involved in the protection and regulation of exercise on heart failure. NEW & NOTEWORTHY Impaired myocardial mitophagy is implicated in the pathogenesis of heart failure. Resistance training alone or combined with different aerobic trainings provide discrepant cardiovascular effects on heart failure, and the cardioprotective function depends on HIF1α-Parkin-mitophagy pathway.
- Published
- 2023
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5. Discovery of a Dysprosium Metallocene Single-Molecule Magnet with Two High-Temperature Orbach Processes.
- Author
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Guo FS, He M, Huang GZ, Giblin SR, Billington D, Heinemann FW, Tong ML, Mansikkamäki A, and Layfield RA
- Abstract
Magnetic bistability in single-molecule magnets (SMMs) is a potential basis for new types of nanoscale information storage material. The standard model for thermally activated relaxation of the magnetization in SMMs is based on the occurrence of a single Orbach process. Here, we show that incorporating a phosphorus atom into the framework of the dysprosium metallocene [(Cp
i Pr5 )Dy(CpPEt4 )]+ [B(C6 F5 )4 ]- (Cpi Pr5 is penta-isopropylcyclopentadienyl, CpPEt4 is tetraethylphospholyl) leads to the occurrence of two distinct high-temperature Orbach processes, with energy barriers of 1410(10) and 747(7) cm-1 , respectively. These barriers provide experimental evidence for two different spin-phonon coupling regimes, which we explain with the aid of ab initio calculations. The strong and highly axial crystal field in this SMM also allows magnetic hysteresis to be observed up to 70 K, using a scan rate of 25 Oe s-1 . In characterizing this SMM, we show that a conventional Debye model and consideration of rotational contributions to the spin-phonon interaction are insufficient to explain the observed phenomena.- Published
- 2022
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6. Synthesis and single-molecule magnet properties of a trimetallic dysprosium metallocene cation.
- Author
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He M, Guo FS, Tang J, Mansikkamäki A, and Layfield RA
- Abstract
The dimetallic fulvalene-bridged dysprosium complex [{Dy(Cp*)(μ-BH4)}2(Fvtttt)] (1, Cp* = C5Me5) is converted into the trimetallic borohydride-bridged species [{Dy(Cp*)(Fvtttt)}2Dy(μ-BH4)3] (2). In turn, 2 is reacted with a silylium electrophile to give [{Dy(Cp*)(μ-BH4)(Fvtttt)}2Dy][B(C6F5)4] ([3][B(C6F5)3]), the first trimetallic dysprosocenium cation. Compound [3][B(C6F5)3] can also be formed directly from 1 by adding two equivalents of the electrophile. A three-fold enhancement in the effective energy barrier from 2 to 3 is observed and interpreted with the aid of ab initio calculations.
- Published
- 2021
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7. Corrigendum: A Dysprosium Metallocene Single-Molecule Magnet Functioning at the Axial Limit.
- Author
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Guo FS, Day BM, Chen YC, Tong ML, Mansikkamäki A, and Layfield RA
- Published
- 2020
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8. Fulvalene as a platform for the synthesis of a dimetallic dysprosocenium single-molecule magnet.
- Author
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He M, Guo FS, Tang J, Mansikkamäki A, and Layfield RA
- Abstract
The dinucleating fulvalenyl ligand [1,1',3,3'-(C
5 t Bu2 H2 )2 ]2- (Fvtttt ) was used to synthesize the dimetallic dysprosocenium cation [{Dy(η5 -Cp*)}2 (μ-BH4 )(η5 :η5 -Fvtttt )]+ ( 3 ) as the salt of [B(C6 F5 )4 ]- (Cp* = C5 Me5 ). Compound [ 3 ][B(C6 F5 )4 ] was obtained using a method in which the double half-sandwich complex [{Dy(BH4 )2 (THF)}2 (Fvtttt )] ( 1 ) was reacted with KCp* to give the double metallocene [{Dy(Cp*)(μ-BH4 )}2 (Fvtttt )] ( 2 ), followed by removal of a bridging borohydride ligand upon addition of [(Et3 Si)2 (μ-H)][B(C6 F5 )4 ]. The dimetallic fulvalenyl complexes 1-3 give rise to single-molecule magnet (SMM) behaviour in zero applied field, with the effective energy barriers of 154(15) cm-1 , 252(4) cm-1 and 384(18) cm-1 , respectively, revealing a significant improvement in performance across the series. The magnetic properties are interpreted with the aid of ab initio calculations, which show substantial increases in the axiality of the crystal field from 1 to 2 to 3 as a consequence of the increasingly dominant role of the Fvtttt and Cp* ligands, with the barrier height and hysteresis properties being attenuated by the equatorial borohydride ligands. The experimental and theoretical results described in this study furnish a blueprint for the design and synthesis of poly-cationic dysprosocenium SMMs with properties that may surpass those of benchmark systems., (This journal is © The Royal Society of Chemistry 2020.)- Published
- 2020
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9. Isolation of a Perfectly Linear Uranium(II) Metallocene.
- Author
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Guo FS, Tsoureas N, Huang GZ, Tong ML, Mansikkamäki A, and Layfield RA
- Abstract
Reduction of the uranium(III) metallocene [(η
5 -C5 i Pr5 )2 UI] (1) with potassium graphite produces the "second-generation" uranocene [(η5 -C5 i Pr5 )2 U] (2), which contains uranium in the formal divalent oxidation state. The geometry of 2 is that of a perfectly linear bis(cyclopentadienyl) sandwich complex, with the ground-state valence electron configuration of uranium(II) revealed by electronic spectroscopy and density functional theory to be 5f3 6d1 . Appreciable covalent contributions to the metal-ligand bonds were determined from a computational study of 2, including participation from the uranium 5f and 6d orbitals. Whereas three unpaired electrons in 2 occupy orbitals with essentially pure 5f character, the fourth electron resides in an orbital defined by strong 7s-6d z 2 mixing., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)- Published
- 2020
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10. Main Group Chemistry at the Interface with Molecular Magnetism.
- Author
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Guo FS, Bar AK, and Layfield RA
- Abstract
Innovative synthetic coordination and, increasingly, organometallic chemistry are at the heart of advances in molecular magnetism. Smart ligand design is essential for implementing controlled modifications to the electronic structure and magnetic properties of transition metal and f-element compounds, and many important recent developments use nontraditional ligands based on low-coordinate main group elements to drive the field forward. This review charts progress in molecular magnetism from the perspective of ligands in which the donor atoms range from low-coordinate 2p elements-particularly carbon but also boron and nitrogen-to the heavier p-block elements such as phosphorus, arsenic, antimony, and even bismuth. Emphasis is placed on the role played by novel main group ligands in addressing magnetic anisotropy of transition metal and f-element compounds, which underpins the development of single-molecule magnets (SMMs), a family of magnetic materials that can retain magnetization in the absence of a magnetic field below a blocking temperature. Nontraditional p-block donor atoms, with their relatively diffuse valence orbitals and more diverse bonding characteristics, also introduce scope for tuning the spin-orbit coupling properties and metal-ligand covalency in molecular magnets, which has implications in areas such as magnetic exchange coupling and spin crossover phenomena. The chemistry encompasses transition metals, lanthanides, and actinides and describes recently discovered molecular magnets that can be regarded, currently, as defining the state of the art. This review identifies that main group chemistry at the interface molecular magnetism is an area with huge potential to deliver new types of molecular magnets with previously unseen properties and applications.
- Published
- 2019
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11. Uranocenium: Synthesis, Structure, and Chemical Bonding.
- Author
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Guo FS, Chen YC, Tong ML, Mansikkamäki A, and Layfield RA
- Abstract
Abstraction of iodide from [(η
5 -C5 i Pr5 )2 UI] (1) produced the cationic uranium(III) metallocene [(η5 -C5 i Pr5 )2 U]+ (2) as a salt of [B(C6 F5 )4 ]- . The structure of 2 consists of unsymmetrically bonded cyclopentadienyl ligands and a bending angle of 167.82° at uranium. Analysis of the bonding in 2 showed that the uranium 5f orbitals are strongly split and mixed with the ligand orbitals, thus leading to non-negligible covalent contributions to the bonding. Investigation of the dynamic magnetic properties of 2 revealed that the 5f covalency leads to partially quenched anisotropy and fast magnetic relaxation in zero applied magnetic field. Application of a magnetic field leads to dominant relaxation by a Raman process., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)- Published
- 2019
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12. Magnetic hysteresis up to 80 kelvin in a dysprosium metallocene single-molecule magnet.
- Author
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Guo FS, Day BM, Chen YC, Tong ML, Mansikkamäki A, and Layfield RA
- Abstract
Single-molecule magnets (SMMs) containing only one metal center may represent the lower size limit for molecule-based magnetic information storage materials. Their current drawback is that all SMMs require liquid-helium cooling to show magnetic memory effects. We now report a chemical strategy to access the dysprosium metallocene cation [(Cp
i Pr5 )Dy(Cp*)]+ (Cpi Pr5 , penta-iso-propylcyclopentadienyl; Cp *, pentamethylcyclopentadienyl), which displays magnetic hysteresis above liquid-nitrogen temperatures. An effective energy barrier to reversal of the magnetization of Ueff = 1541 wave number is also measured. The magnetic blocking temperature of TB = 80 kelvin for this cation overcomes an essential barrier toward the development of nanomagnet devices that function at practical temperatures., (Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)- Published
- 2018
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13. Rare-Earth Cyclobutadienyl Sandwich Complexes: Synthesis, Structure and Dynamic Magnetic Properties.
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Day BM, Guo FS, Giblin SR, Sekiguchi A, Mansikkamäki A, and Layfield RA
- Abstract
The potassium cyclobutadienyl [K
2 {η4 -C4 (SiMe3 )4 }] (1) reacts with MCl3 (THF)3.5 (M=Y, Dy) to give the first rare-earth cyclobutadienyl complexes, that is, the complex anions [M{η4 -C4 (SiMe3 )4 }{η4 -C4 (SiMe3 )3 -κ-(CH2 SiMe2 }]2- , (2M ), as their dipotassium salts. The tuck-in alkyl ligand in 2M is thought to form through deprotonation of the "squarocene" complexes [M{η4 -C4 (SiMe3 )4 }2 ]- by 1. Complex 2Dy is a single-molecule magnet, but with prominent quantum tunneling. An anisotropy barrier of 323(22) cm-1 was determined for 2Dy in an applied field of 1 kOe, and magnetic hysteresis loops were observed up to 7 K., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)- Published
- 2018
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14. Two isostructural Ln-MOFs showing luminescent sensing (Eu) and slow magnetic relaxation (Dy) properties.
- Author
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Yang C, Zheng JY, Cai WJ, Guo FS, and Wang YY
- Abstract
Two isostructural lanthanide-based MOFs [Ln(HL)L]·H2O (1-Ln, Ln = Eu, Dy, H2L = 5-((pyridin-4-ylthio)methyl)isophthalic acid) were successfully obtained via the solvothermal reaction. 1-Eu exhibits high fluorescence quenching efficiency for C2O72- and Fe3+, which can be potentially used as a luminescent probe; 1-Dy behaves as a typical single-molecule magnet with an energy barrier (ΔUeff) of 54(2) K.
- Published
- 2018
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15. Cyclopentadienyl Ligands in Lanthanide Single-Molecule Magnets: One Ring To Rule Them All?
- Author
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Day BM, Guo FS, and Layfield RA
- Abstract
The discovery of materials capable of storing magnetic information at the level of single molecules and even single atoms has fueled renewed interest in the slow magnetic relaxation properties of single-molecule magnets (SMMs). The lanthanide elements, especially dysprosium, continue to play a pivotal role in the development of potential nanoscale applications of SMMs, including, for example, in molecular spintronics and quantum computing. Aside from their fundamentally fascinating physics, the realization of functional materials based on SMMs requires significant scientific and technical challenges to be overcome. In particular, extremely low temperatures are needed to observe slow magnetic relaxation, and while many SMMs possess a measurable energy barrier to reversal of the magnetization ( U
eff ), very few such materials display the important properties of magnetic hysteresis with remanence and coercivity. Werner-type coordination chemistry has been the dominant method used in the synthesis of lanthanide SMMs, and most of our knowledge and understanding of these materials is built on the many important contributions based on this approach. In contrast, lanthanide organometallic chemistry and lanthanide magnetochemistry have effectively evolved along separate lines, hence our goal was to promote a new direction in single-molecule magnetism by uniting the nonclassical organometallic synthetic approach with the traditionally distinct field of molecular magnetism. Over the last several years, our work on SMMs has focused on obtaining a detailed understanding of why magnetic materials based on the dysprosium metallocene cation building block {Cp2 Dy}+ display slow magnetic relaxation. Specifically, we aspired to control the SMM properties using novel coordination chemistry in a way that hinges on key considerations, such as the strength and the symmetry of the crystal field. In establishing that the two cyclopentadienyl ligands combine to provide a strongly axial crystal field, we were able to propose a robust magneto-structural correlation for understanding the properties of dysprosium metallocene SMMs. In doing so, a blueprint was established that allows Ueff and the magnetic blocking temperature ( TB ) to be improved in a well-defined way. Although experimental discoveries with SMMs occur more rapidly than quantitative theory can (currently) process and explain, a clear message emanating from the literature is that a combination of the two approaches is most effective. In this Account, we summarize the main findings from our own work on dysprosium metallocene SMMs, and consider them in the light of related experimental studies and theoretical interpretations of related materials reported by other protagonists. In doing so, we aim to contribute to the nascent and healthy debate on the nature of spin dynamics in SMMs and allied molecular nanomagnets, which will be crucial for the further advancement of this vibrant research field.- Published
- 2018
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16. Single-molecule magnet properties of a monometallic dysprosium pentalene complex.
- Author
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Kilpatrick AFR, Guo FS, Day BM, Mansikkamäki A, Layfield RA, and Cloke FGN
- Abstract
The pentalene-ligated dysprosium complex [(η8-Pn†)Dy(Cp*)] (1Dy) (Pn† = [1,4-(iPr3Si)2C8H4]2-) and its magnetically dilute analogue are single-molecule magnets, with energy barriers of 245 cm-1. Whilst the [Cp*]- ligand in 1Dy provides a strong axial crystal field, the overall axiality of this system is attenuated by the unusual folded structure of the [Pn†]2- ligand.
- Published
- 2018
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17. [Variability of peripheral arterial peak velocity predicts fluid responsiveness in patients with septic shock].
- Author
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Lu N, Jiang L, Zhu B, Han W, Zhao Y, Shi Y, Guo F, and Xi X
- Subjects
- Central Venous Pressure, Fluid Therapy, Hemodynamics, Humans, Prospective Studies, ROC Curve, Respiration, Artificial, Stroke Volume, Shock, Septic
- Abstract
Objective: To explore the accuracy of fluid responsiveness assessment by variability of peripheral arterial peak velocity and variability of inferior vena cava diameter (ΔIVC) in patients with septic shock., Methods: A prospective study was conducted. The patients with septic shock undergoing mechanical ventilation (MV) admitted to intensive care unit (ICU) of Beijing Electric Power Hospital from January 2016 to December 2017 were enrolled. According to sepsis bundles of septic shock, volume expansion (VE) was conducted. The increase in cardiac index (ΔCI) after VE ≥ 10% was defined as liquid reaction positive (responsive group), ΔCI < 10% was defined as the liquid reaction negative (non-responsive group). The hemodynamic parameters [central venous pressure (CVP), intrathoracic blood volume index (ITBVI), stroke volume variation (SVV), ΔIVC, variability of carotid Doppler peak velocity (ΔCDPV), and variability of brachial artery peak velocity (ΔVpeak-BA)] before and after VE were monitored. The correlations between the hemodynamic parameters and ΔCI were explored by Pearson correlation analysis. Receiver operating characteristic (ROC) curve was plotted to analyze the predictive value of all hemodynamic parameters on fluid responsiveness., Results: During the study, 74 patients with septic shock were included, of whom 9 were excluded because of peripheral artery stenosis, recurrent arrhythmia or abdominal distension influencing the ultrasound examination, and 65 patients were finally enrolled in the analysis. There were 31 patients in the responsive group and 34 in the non-responsive group. SVV, ΔIVC, ΔCDPV and ΔVpeak-BA before VE in responsive group were significantly higher than those of the non-responsive group [SVV: (12.3±2.4)% vs. (9.2±2.1)%, ΔIVC: (22.3±5.3)% vs. (15.5±3.7)%, ΔCDPV: (15.3±3.3)% vs. (10.3±2.4)%, ΔVpeak-BA: (14.5±3.3)% vs. (9.6±2.3)%, all P < 0.05]. There was no significant difference in CVP [mmHg (1 mmHg = 0.133 kPa): 7.5±2.5 vs. 8.2±2.6] or ITBVI (mL/m
2 : 875.2±173.2 vs. 853.2±192.0) between the responsive group and non-responsive group (both P > 0.05). There was no significant difference in hemodynamic parameter after VE between the two groups. Correlation analysis showed that SVV, ΔIVC, ΔCDPV, and ΔVpeak-BA before VE showed significant linearity correlation with ΔCI (r value was 0.832, 0.813, 0.854, and 0.814, respectively, all P < 0.05), but no correlation was found between CVP and ΔCI (r = -0.342, P > 0.05) as well as ITBVI and ΔCI (r = -0.338, P > 0.05). ROC curve analysis showed that the area under ROC curve (AUC) of SVV, ΔIVC, ΔCDPV, and ΔVpeak-BA before VE for predicting fluid responsiveness was 0.857, 0.826, 0.906, and 0.866, respectively, which was significantly higher than that of CVP (AUC = 0.611) and ITBVI (AUC = 0.679). When the optimal cut-off value of SVV for predicting fluid responsiveness was 11.5%, the sensitivity was 70.4%, and the specificity was 94.7%. When the optimal cut-off value of ΔIVC was 20.5%, the sensitivity was 60.3%, and the specificity was 89.7%. When the optimal cut-off value of ΔCDPV was 13.0%, the sensitivity was 75.2%, and the specificity was 94.9%. When the optimal cut-off value of ΔVpeak-BA was 12.7%, the sensitivity was 64.8%, and the specificity was 89.7%., Conclusions: Ultrasound assessment of ΔIVC, ΔCDPV, and ΔVpeak-BA could predict fluid responsiveness in patients with septic shock receiving mechanical ventilation. ΔCDPV had the highest predictive value among these parameters.- Published
- 2018
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18. Sensing and Transmitting Intracellular Amino Acid Signals through Reversible Lysine Aminoacylations.
- Author
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He XD, Gong W, Zhang JN, Nie J, Yao CF, Guo FS, Lin Y, Wu XH, Li F, Li J, Sun WC, Wang ED, An YP, Tang HR, Yan GQ, Yang PY, Wei Y, Mao YZ, Lin PC, Zhao JY, Xu Y, Xu W, and Zhao SM
- Subjects
- Amino Acyl-tRNA Synthetases metabolism, Apoptosis, Biocatalysis, HEK293 Cells, Humans, Mechanistic Target of Rapamycin Complex 1 metabolism, Substrate Specificity, Aminoacylation, Intracellular Space metabolism, Lysine metabolism, Signal Transduction
- Abstract
Amino acids are known regulators of cellular signaling and physiology, but how they are sensed intracellularly is not fully understood. Herein, we report that each aminoacyl-tRNA synthetase (ARS) senses its cognate amino acid sufficiency through catalyzing the formation of lysine aminoacylation (K-AA) on its specific substrate proteins. At physiologic levels, amino acids promote ARSs bound to their substrates and form K-AAs on the ɛ-amine of lysines in their substrates by producing reactive aminoacyl adenylates. The K-AA marks can be removed by deacetylases, such as SIRT1 and SIRT3, employing the same mechanism as that involved in deacetylation. These dynamically regulated K-AAs transduce signals of their respective amino acids. Reversible leucylation on ras-related GTP-binding protein A/B regulates activity of the mammalian target of rapamycin complex 1. Glutaminylation on apoptosis signal-regulating kinase 1 suppresses apoptosis. We discovered non-canonical functions of ARSs and revealed systematic and functional amino acid sensing and signal transduction networks., (Copyright © 2017 Elsevier Inc. All rights reserved.)
- Published
- 2018
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19. A 45 nm Stacked CMOS Image Sensor Process Technology for Submicron Pixel.
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Takahashi S, Huang YM, Sze JJ, Wu TT, Guo FS, Hsu WC, Tseng TH, Liao K, Kuo CC, Chen TH, Chiang WC, Chuang CH, Chou KY, Chung CH, Chou KY, Tseng CH, Wang CJ, and Yaung DN
- Abstract
A submicron pixel's light and dark performance were studied by experiment and simulation. An advanced node technology incorporated with a stacked CMOS image sensor (CIS) is promising in that it may enhance performance. In this work, we demonstrated a low dark current of 3.2 e
- /s at 60 °C, an ultra-low read noise of 0.90 e- ·rms, a high full well capacity (FWC) of 4100 e- , and blooming of 0.5% in 0.9 μm pixels with a pixel supply voltage of 2.8 V. In addition, the simulation study result of 0.8 μm pixels is discussed., Competing Interests: The authors declare no conflict of interest.- Published
- 2017
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20. Thermal expansion and magnetic properties of benzoquinone-bridged dinuclear rare-earth complexes.
- Author
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Moilanen JO, Mansikkamäki A, Lahtinen M, Guo FS, Kalenius E, Layfield RA, and Chibotaru LF
- Abstract
The synthesis and structural characterization of two benzoquinone-bridged dinuclear rare-earth complexes [BQ(MCl
2 ·THF3 )2 ] (BQ = 2,5-bisoxide-1,4-benzoquinone; M = Y (1), Dy (2)) are described. Of these reported metal complexes, the dysprosium analogue 2 is the first discrete bridged dinuclear lanthanide complex in which both metal centres reside in pentagonal bipyramidal environments. Interestingly, both complexes undergo significant thermal expansion upon heating from 120 K to 293 K as illustrated by single-crystal X-ray and powder diffraction experiments. AC magnetic susceptibility measurements reveal that 2 does not show the slow relation of magnetization in zero dc field. The absent of single-molecule behaviour in 2 arises from the rotation of the principal magnetic axis as compared to the pseudo-C5 axis of the pentagonal bipyramidal environment as suggested by ab initio calculations. The cyclic voltammetry and chemical reduction experiments demonstrated that complexes 1 and 2 can be reduced to radical species containing [BQ3 ˙- ]. This study establishes efficient synthetic strategy to make bridged redox-active multinuclear lanthanide complexes with a pentagonal bipyramidal coordination environment that are potential precursors for single-molecule magnets.- Published
- 2017
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21. A Dysprosium Metallocene Single-Molecule Magnet Functioning at the Axial Limit.
- Author
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Guo FS, Day BM, Chen YC, Tong ML, Mansikkamäki A, and Layfield RA
- Abstract
Abstraction of a chloride ligand from the dysprosium metallocene [(Cp
ttt )2 DyCl] (1Dy Cpttt =1,2,4-tri(tert-butyl)cyclopentadienide) by the triethylsilylium cation produces the first base-free rare-earth metallocenium cation [(Cpttt )2 Dy]+ (2Dy ) as a salt of the non-coordinating [B(C6 F5 )4 ]- anion. Magnetic measurements reveal that [2Dy ][B(C6 F5 )4 ] is an SMM with a record anisotropy barrier up to 1277 cm-1 (1837 K) in zero field and a record magnetic blocking temperature of 60 K, including hysteresis with coercivity. The exceptional magnetic axiality of 2Dy is further highlighted by computational studies, which reveal this system to be the first lanthanide SMM in which all low-lying Kramers doublets correspond to a well-defined MJ value, with no significant mixing even in the higher doublets., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)- Published
- 2017
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22. Activation of C-H bonds by rare-earth metallocene-butyl complexes.
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Grindell R, Day BM, Guo FS, Pugh T, and Layfield RA
- Abstract
The stable metallocene-butyl complexes [(Cp
Me )2 M(n Bu)]2 (M = Y, Dy) were synthesized and their reactivity towards to ferrocene and bulky N-heterocyclic carbenes investigated. Selective mono-deprotonation of ferrocene and a benzylic methyl group of IMes were observed, whereas a control reaction of (CpMe )3 M with IMes resulted in a normal-to-abnormal NHC rearrangement.- Published
- 2017
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23. Strong direct exchange coupling and single-molecule magnetism in indigo-bridged lanthanide dimers.
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Guo FS and Layfield RA
- Abstract
The synthesis, structure and magnetic properties of the indigo-bridged dilanthanide complexes [{(η
5 -Cp*)2 Ln}2 (μ-ind)]n- with Ln = Gd or Dy and n = 0, 1 or 2 are described. The gadolinium complexes with n = 0 and 2 show typically weak exchange coupling, whereas the complex bridged by the radical [ind]3- ligand shows an unusually large coupling constant of J = -11 cm-1 (-2J formalism). The dysprosium complexes with n = 0 and 1 are single-molecule magnets in zero applied field, whereas the complex with n = 2 does not show slow magnetic relaxation.- Published
- 2017
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24. Two {Dy 2 } single-molecule magnets formed via an in situ reaction by capturing CO 2 from atmosphere under ambient conditions.
- Author
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Zhang K, Guo FS, and Wang YY
- Abstract
Under ambient conditions, CO
2 was captured from atmosphere and reduced for sequestering CO2 into two {Dy2 } single-molecule magnets through an in situ organic ligand reaction of hydrazine. A reasonable reaction mechanism is proposed, which provides a promising route towards the capturing and transforming CO2 into single-molecule magnets.- Published
- 2017
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25. Transitions of two magnetic interaction states in dinuclear Dy(iii) complexes via subtle structural variations.
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Zhang K, Liu D, Vieru V, Hou L, Cui B, Guo FS, Chibotaru LF, and Wang YY
- Abstract
Herein we explored the transitions of two magnetic interaction states (antiferromagnetic or ferromagnetic) upon structural variations in two dinuclear Dy(iii) complexes.
- Published
- 2017
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26. Fine-tuning terminal solvent ligands to rationally enhance the energy barrier in dinuclear dysprosium single-molecule magnets.
- Author
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Zhang K, Yuan C, Guo FS, Zhang YQ, and Wang YY
- Abstract
In search of simple approaches to rationally enhance the energy barriers in polynuclear dysprosium single-molecule magnets, a new system containing two structurally closely related dinuclear dysprosium complexes, namely [Dy
2 (L)2 (DBM)2 (DMF)2 ] (1) and [Dy2 (L)2 (DBM)2 (DMA)2 ]·2DMA (2) (HDBM = dibenzoylmethane, H2 L = 2-hydroxy-N'-(2-hydroxy-3-methoxybenzylidene)benzohydrazide), is introduced and the structure-dependent magnetic properties are investigated. The two complexes display only slight variations in the coordination geometries of the Dy(iii) ion but display remarkably different magnetic behaviors. By replacing the DMF (dimethylformamide) ligand in complex 1 with DMA (dimethylacetamide) in 2 while retaining the same coordination atoms, we were able to create a 3-fold enhancement in the energy barrier, from 24 K for complex 1 to 77 K for complex 2. Complete-active-space self-consistent field (CASSCF) calculations revealed that the charge distribution surrounding the Dy(iii) centers in 1 and 2 is the key factor in determining the relaxation properties of the SMMs. The introduction of an electron-donating CH3 group in DMA to replace the hydrogen in DMF resulted in a larger average charge along the magnetic axes of complex 2 compared to complex 1, which resulted in a stronger easy-axis ligand field, thus increasing the energy difference between the ground and the first excited states of complex 2. This work presents a simple method to rationally enhance the energy barrier in polynuclear lanthanide SMMs through fine-tuning of the electrostatic potential of the atoms along the magnetic axis.- Published
- 2016
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27. Two 3D Isostructural Ln(III)-MOFs: Displaying the Slow Magnetic Relaxation and Luminescence Properties in Detection of Nitrobenzene and Cr 2 O 7 2 .
- Author
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Gao RC, Guo FS, Bai NN, Wu YL, Yang F, Liang JY, Li ZJ, and Wang YY
- Abstract
Two new three-dimensional isostructural lanthanide metal-organic frameworks (Ln(III)-MOFs), [LnL(H
2 O)3 ]·3H2 O·0.75DMF (1-Ln; Ln = Dy(III) and Eu(III) ions, H3 L = biphenyl-3'-nitro-3,4',5-tricarboxylic acid, DMF = N,N'-dimethylformamide), were synthesized and characterized. The appearance of temperature-dependent out-of-phase (χ″M ) signal reveals that complex 1-Dy displays slow magnetic relaxation behavior with the energy barrier (ΔUeff ) of 57 K and a pre-exponential factor (τ0 ) of 3.89 × 10-8 s at 1200 Oe direct current field. The luminescence explorations demonstrated that 1-Eu exhibits high quenching efficiency and low detection limit for sensing nitrobenzene and Cr2 O7 2- . Meanwhile, the fluorescence intensity of the quenched 1-Eu samples will be resumed after washing with DMF or water, indicating that 1-Eu may be used as a highly selective and recyclable luminescence sensing material for sensing nitrobenzene and Cr2 O7 2- anion.- Published
- 2016
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28. The future of remote ECG monitoring systems.
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Guo SL, Han LN, Liu HW, Si QJ, Kong DF, and Guo FS
- Abstract
Remote ECG monitoring systems are becoming commonplace medical devices for remote heart monitoring. In recent years, remote ECG monitoring systems have been applied in the monitoring of various kinds of heart diseases, and the quality of the transmission and reception of the ECG signals during remote process kept advancing. However, there remains accompanying challenges. This report focuses on the three components of the remote ECG monitoring system: patient (the end user), the doctor workstation, and the remote server, reviewing and evaluating the imminent challenges on the wearable systems, packet loss in remote transmission, portable ECG monitoring system, patient ECG data collection system, and ECG signals transmission including real-time processing ST segment, R wave, RR interval and QRS wave, etc. This paper tries to clarify the future developmental strategies of the ECG remote monitoring, which can be helpful in guiding the research and development of remote ECG monitoring.
- Published
- 2016
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29. Two Isostructural Metal-Organic Frameworks Directed by the Different Center Metal Ions, Exhibiting the Ferrimagnetic Behavior and Slow Magnetic Relaxation.
- Author
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Wu YL, Guo FS, Yang GP, Wang L, Jin JC, Zhou X, Zhang WY, and Wang YY
- Abstract
Two 3D isostructural metal-organic frameworks with 1D ferrimagnetic chains, formulated as [M3(L)(μ3-OH)2(H2O)4] [H4L = (1,1':4',1″-terphenyl)-2',3,3″,5'-tetracarboxylic acid, where M = Mn for 1 and Co for 2], have been successfully synthesized by employing different center metal ions and a multicarboxylate ligand under identical reaction conditions in this work. The single-crystal X-ray diffraction data of 1 and 2 reveal that the complexes are two 3D isostructural frameworks based on 1D [M3(OH)2]n chains composed of triangular subunits as rod-shaped secondary building units, which are classified as binodal 4,6-connected fry nets with the point symbol (5(10)·6(3)·7(8))(5(4)·6(2)). The magnetic properties revealed that complexes 1 and 2 exhibit ferrimagnetic behavior. Also, the alternating-current susceptibility of 2 displays slow magnetic relaxation, showing interesting magnetic behavior of a single-chain magnet with an effective energy barrier of 32 K.
- Published
- 2016
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30. Structural diversity of five new bitriazole-based complexes: luminescence, sorption, and magnetic properties.
- Author
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Du LY, Wang H, Liu G, Xie D, Guo FS, Hou L, and Wang YY
- Abstract
Employing an uninvestigated eight N-donor bitriazole ligand, 5'-(pyrazin-2-yl)-2H,4'H-3,3'-bi(1,2,4-triazole) (H2pzbtz), five complexes, {[Zn2(pzbtz)(SO4)(H2O)2]·2H2O}n (), {[Cd(pzbtz)]·3H2O}n (), [Zn3(Hpzbtz)2(SO4)2(H2O)6] (), [Co(Hpzbtz)2(H2O)2] () and {[Co2(pzbtz)2(H2O)2]·4H2O}n (), have been solvothermally synthesised by altering the reaction solvents and temperatures. Complex shows a three-dimensional (3D) framework with a very rare (3,5)-connected fsc-3,5-Cmce-2 topology. Complex exhibits a (4,4)-connected 3D pts framework with 1D channels. Complexes and are discrete trinuclear and mononuclear molecules, respectively. Complex presents a chiral 3D framework based on a novel trinuclear Co3(tr)4 cluster and features an unusual six-connected lcy topology. In the five complexes, H2pzbtz show a very variety of geometrical configurations and coordination modes. Due to the planarity of H2pzbtz, complexes display strong photoluminescence; in particular, features highly selective luminescent sensing for the Cu(2+) ion and nitrobenzene molecule. In addition, shows highly selective adsorption for CO2 over CH4, and exhibits antiferromagnetic exchange interactions among the Co(2+) ions.
- Published
- 2015
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31. Enhanced spin-crossover behavior mediated by supramolecular cooperative interactions.
- Author
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Yan Z, Li JY, Liu T, Ni ZP, Chen YC, Guo FS, and Tong ML
- Abstract
Three one-dimensional (1D) hetereobimetallic coordination polymers [Fe(II)(L)2(AgCN)2]·Solv (L = bpt(-), 1; L = Mebpt(-), Solv = 1.75EtOH, 2; L = bpzt(-), 3) with in situ generated AgCN species were synthesized by solvothermal reactions of Fe(II) salt, K[Ag(CN)2], and the corresponding ligands [bptH = 3,5-bis(pyridin-2-yl)-1,2,4-triazole, MebptH = 3-(3-methyl-2-pyridyl)-5-(2-pyridyl)-1,2,4-triazole, and bpztH = 3,5-bis(pyrazin-2-yl)-1,2,4-triazole]. They were further characterized by X-ray crystallography, magnetic and photomagnetic measurements, and differential scanning calorimetry. Single-crystal X-ray analyses show that they are isostructural with 1D zigzag chain structures with rhombus {Fe2Ag2} units, in which the substituted bpt(-) ligand connects the Fe(II) ion and AgCN species in a cis bridging mode. Then the zigzag chains are packed into three-dimensional supramolecular structures by π···π interactions. Most importantly, weak Ag···N interactions (2.750 Å at 150 K) between the π-stacked neighboring chains present in complex 3. Magnetic susceptibility measurements exhibit that complex 1 displays characteristic paramagnetic behavior in the temperature range investigated. Complex 2 undergoes a gradual spin-crossover (SCO) with critical temperatures T(1/2)↓ = 232 K and T(1/2)↑ = 235 K, whereas 3 exhibits an abrupt SCO with critical temperatures T(1/2)↓ = 286 K and T(1/2)↑ = 292 K. The magnetostructural relationships suggest that the magnetic behaviors can be modulated from paramagnetic behavior to abrupt and hysteretic SCO near room temperature through adjustment of the electronic substituent effect and intermolecular interactions.
- Published
- 2014
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32. A chiral spin crossover metal-organic framework.
- Author
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Liu W, Bao X, Mao LL, Tucek J, Zboril R, Liu JL, Guo FS, Ni ZP, and Tong ML
- Abstract
A chiral metal-organic framework exhibiting spin crossover (SCO) property, [Fe(II)(mptpy)2]·EtOH·0.2DMF (·solv), has been solvothermally synthesized through spontaneous resolution. It displays remarkable stability and two-step SCO at (Tc1 = 200 K) and above (Tc2 = 357 K) room temperature.
- Published
- 2014
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33. Switching of the magnetocaloric effect of Mn(II) glycolate by water molecules.
- Author
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Chen YC, Guo FS, Liu JL, Leng JD, Vrábel P, Orendáč M, Prokleška J, Sechovský V, and Tong ML
- Abstract
The transformation of Mn(II) glycolates (glc) between the three-dimensional coordination polymer [Mn(glc)2]n (1) and discrete mononuclear phase [Mn(glc)2 (H2O)2] (2) can be reversibly switched by water molecules, which dramatically change the magnetocaloric effect (MCE) of Mn(II) glycolates from the maximum of 6.9 J kg(-1) K(-1) in 1 to 60.3 J kg(-1) K(-1) in 2. This case example reveals that the effect of magnetic coupling on MCE plays a dominant role over that of other factors such as magnetic density for 3d-type magnetic refrigerants., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2014
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34. Spin-crossover behavior in two new supramolecular isomers.
- Author
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Yan Z, Ni ZP, Guo FS, Li JY, Chen YC, Liu JL, Lin WQ, Aravena D, Ruiz E, and Tong ML
- Abstract
Two spin-crossover (SCO) supramolecular isomers formulated as [Fe(Mebpt){Au(CN)2}]n·xH2O (1, x = 0, and 2·H2O, x = n, MebptH = 3-(5-methyl-2-pyridyl)-5-(2-pyridyl)-1,2,4-triazole) have been successfully isolated and characterized by single-crystal X-ray crystallography, thermogravimetric analysis, differential scanning calorimetry, variable-temperature powder X-ray diffraction, and magnetic measurements. Structural analysis reveals that 1 is a two-dimensional coordination layer and 2·H2O is a one-dimensional coordination ladder structure, in which the Mebpt(-) ligands are coordinated in trans and cis bridging mode in 1 and 2·H2O, respectively. Dramatically, their SCO properties are further influenced by the octahedral coordination configuration of Fe(II). In 1, only the Fe(II) centers in trans configuration exhibit spin transition (Tc = 303 K), while in 2·H2O and the dehydrated 2, gradual two-step SCO (Tc1 = 235 K, Tc2 = 313 K) and one-step SCO behaviors (Tc = 315 K) occur, respectively.
- Published
- 2014
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35. [Study of relation between crushed lava spectrum and magnetic susceptibility in Xiangshan uranium orefield].
- Author
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Wu ZC, Guo FS, Liu LQ, and Jiang YB
- Abstract
Rock spectrum research is the base of the remote sensing geology. It's of great significance of exploring the relations between rock spectrum and other rock natures. In the present study, 36 fine crushed lava samples each measuring 5 cmX5 cmX 5 cm were tested for its spectrums by SVC HR-768 portable spectrometer. But before measuring each sample, white boards should be calibrated and after measuring the curves of spectrum of each sample should make a 5 nm smooth resample so that meteoric water and noise caused by external environment can be eliminated. After such smooth resample, at the spectrum scope of 1 112-1322 nm, taking band value as horizontal axis and reflectivity as vertical axis, linear equations of rock samples can be obtained. Taking the slopes as the horizontal axis and volume magnetic susceptibility as vertical axis, y= -0. 256 31n(x) + 0. 913 7 was thus obtained and its equation correlation coefficient is up to 0. 78. The result shows that volume magnetic susceptibility is mainly caused by Fe2+ , and that the amount of Fe2+ can be almost measured in the spectrum scope of 1112 approximately 1322 nm that has a good correlation with volume magnetic susceptibility.
- Published
- 2013
36. Anion-templated assembly and magnetocaloric properties of a nanoscale {Gd38} cage versus a {Gd48} barrel.
- Author
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Guo FS, Chen YC, Mao LL, Lin WQ, Leng JD, Tarasenko R, Orendáč M, Prokleška J, Sechovský V, and Tong ML
- Abstract
The comprehensive study reported herein provides compelling evidence that anion templates are the main driving force in the formation of two novel nanoscale lanthanide hydroxide clusters, {Gd38(ClO4)6} (1) and {Gd48Cl2(NO3)} (2), characterized by single-crystal X-ray crystallography, infrared spectroscopy, and magnetic measurements. {Gd38(ClO4)6}, encapsulating six ClO4(-) ions, features a cage core composed of twelve vertex-sharing {Gd4} tetrahedrons and one Gd⋅⋅⋅Gd pillar. When Cl(-) and NO3(-) were incorporated in the reaction instead of ClO4(-), {Gd48Cl2(NO3)} is obtained with a barrel shape constituted by twelve vertex-sharing {Gd4} tetrahedrons and six {Gd5} pyramids. What is more, the cage-like {Gd38} can be dynamically converted into the barrel-shaped {Gd48} upon Cl(-) and NO3(-) stimulus. To our knowledge, it is the first time that the linear M-O-M' fashion and the unique μ8-ClO4(-) mode have been crystallized in pure lanthanide complex, and complex 2 represents the largest gadolinium cluster. Both of the complexes display large magnetocaloric effect in units of J kg(-1) K(-1) and mJ cm(-3) K(-1) on account of the weak antiferromagnetic exchange, the high N(Gd)/M(W) ratio (magnetic density), and the relatively compact crystal lattice (mass density)., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2013
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37. Gadolinium(III)-hydroxy ladders trapped in succinate frameworks with optimized magnetocaloric effect.
- Author
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Chen YC, Guo FS, Zheng YZ, Liu JL, Leng JD, Tarasenko R, Orendáč M, Prokleška J, Sechovský V, and Tong ML
- Abstract
Two kinds of inorganic gadolinium(III)-hydroxy "ladders", [2×n] and [3×n], were successfully trapped in succinate (suc) coordination polymers, [Gd2(OH)2(suc)2(H2O)]n·2nH2O (1) and [Gd6(OH)8(suc)5(H2O)2 ]n·4n H2O (2), respectively. Such coordination polymers could be regarded as alternating inorganic-organic hybrid materials with relatively high density. Magnetic and heat capacity studies reveal a large cryogenic magnetocaloric effect (MCE) in both compounds, namely (ΔH=70 kG) 42.8 J kg(-1) K(-1) for complex 1 and 48.0 J kg(-1) K(-1) for complex 2. The effect of the high density is evident, which gives very large volumetric MCEs up to 120 and 144 mJ cm(-3) K(-1) for complexes 1 and 2, respectively., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2013
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38. Wheel-shaped nanoscale 3d-4f {Co(II)16Ln(III)24} clusters (Ln = Dy and Gd).
- Author
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Zhang ZM, Pan LY, Lin WQ, Leng JD, Guo FS, Chen YC, Liu JL, and Tong ML
- Abstract
Two unprecedented wheel-shaped nanoscale clusters {Co(II)16Ln(III)24} (Ln = Dy and Gd), with a diameter and a thickness of 3.0 nm and 2.0 nm, respectively, were obtained from the self-assembly of Co(NO3)2, Ln(NO3)3 and a pyridyl-functionalized β-diketone ligand. Notably, the gadolinium species exhibited a relatively large magnetocaloric effect.
- Published
- 2013
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39. Lanthanide oxide clusters: from tetrahedral [Dy4(μ4-O)](10+) to supertetrahedral [Ln20(μ4-O)11]38+ (Ln = Tb, Dy, Ho, Er).
- Author
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Lin WQ, Liao XF, Jia JH, Leng JD, Liu JL, Guo FS, and Tong ML
- Abstract
Supertetrahedral clusters: A family of lanthanide oxide supertetrahedral T3{Ln20} clusters (Ln = Tb, Dy, Ho, Er; see figure) were obtained from the solvothermal reaction of lanthanide(III) salts with polytriazolate ligands that could be methylated and oxidized in situ., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2013
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40. Multifunctional Dy(III)4 cluster exhibiting white-emitting, ferroelectric and single-molecule magnet behavior.
- Author
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Guo PH, Liu JL, Jia JH, Wang J, Guo FS, Chen YC, Lin WQ, Leng JD, Bao DH, Zhang XD, Luo JH, and Tong ML
- Published
- 2013
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41. Relaxations in heterolanthanide dinuclear single-molecule magnets.
- Author
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Leng JD, Liu JL, Zheng YZ, Ungur L, Chibotaru LF, Guo FS, and Tong ML
- Abstract
A heterospin dinuclear complex [Dy(0.87)Yb(1.13)(H(2)cht)(2)Cl(4)(H(2)O)(MeCN)]·MeCN shows shifts of the relaxation barriers with respect to the barriers observed in homospin Dy(2) and Yb(2) isostructural complexes. The origin of slow relaxation in the latter two compounds was elucidated by ab initio calculations.
- Published
- 2013
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42. Symmetry-related [Ln(III)6Mn(III)12] clusters toward single-molecule magnets and cryogenic magnetic refrigerants.
- Author
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Liu JL, Lin WQ, Chen YC, Leng JD, Guo FS, and Tong ML
- Abstract
A family of high-nuclearity [Ln(III)(6)Mn(III)(12)] (Ln = Gd, Tb) nanomagnets has been synthesized, of which two are in D(2) molecular symmetry and the other two are in C(1) symmetry. X-ray crystallography shows that each of them contains a similar {Mn(III)(8)O(13)} unit, four marginal Mn(III) ions, and two linear {Ln(III)(3)} units with parallel or perpendicular orientation for high- and low-symmetry cores, respectively. For [Gd(III)(6)Mn(III)(12)], the distinct spins of the {Mn(III)(8)O(13)} unit lead to different spin ground states (S(T) = 23 for the high-symmetry one and S(T) = 16 for the low-symmetry one), and significant magnetocaloric effects are observed in a wide temperature range [full width at half-maximum (FWHM) of -ΔS(m) > 18 K] that can maximizes the refrigerant capacity, which may be attributed to the ferromagnetic interactions. By replacement of isotropic Gd(III) with anisotropic Tb(III), they behave as single-molecule magnets, with the high-symmetry one possessing a larger effective barrier (36.6 K) than the low-symmetry one (19.6 K).
- Published
- 2013
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43. A large cryogenic magnetocaloric effect exhibited at low field by a 3D ferromagnetically coupled Mn(II)-Gd(III) framework material.
- Author
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Guo FS, Chen YC, Liu JL, Leng JD, Meng ZS, Vrábel P, Orendáč M, and Tong ML
- Abstract
The large cryogenic magnetocaloric effect of a 3D oxydiacetate-bridged gadolinium-manganese MOF material, [Mn(H(2)O)(6)][MnGd(oda)(3)](2)·6H(2)O (1), was evaluated by magnetization and heat capacity measurements. A maximum -ΔS(m) of 50.1 J kg(-1) K(-1) for ΔH = 70 kG along with significant entropy change at lower field was found on account of the weak Mn···Gd ferromagnetic interactions and the small molecular mass. This suggests that 1 could be considered as a potential coolant for liquid helium temperature applications.
- Published
- 2012
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44. A six-coordinate ytterbium complex exhibiting easy-plane anisotropy and field-induced single-ion magnet behavior.
- Author
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Liu JL, Yuan K, Leng JD, Ungur L, Wernsdorfer W, Guo FS, Chibotaru LF, and Tong ML
- Abstract
The field-induced blockage of magnetization behavior was first observed in an Yb(III)-based molecule with a trigonally distorted octahedral coordination environment. Ab initio calculations and micro-SQUID measurements were performed to demonstrate the exhibition of easy-plane anisotropy, suggesting the investigated complex is the first pure lanthanide field-induced single-ion magnet (field-induced SIM) of this type. Furthermore, we found the relaxation time obeys a power law instead of an exponential law, indicating that the relaxation process should be involved a direct process rather than an Orbach process.
- Published
- 2012
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45. Heterometallic cubane-like {M2Ln2} (M = Ni, Zn; Ln =, Gd, Dy) and {Ni2Y2} aggregates. Synthesis, structures and magnetic properties.
- Author
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Meng ZS, Guo FS, Liu JL, Leng JD, and Tong ML
- Abstract
The syntheses, structural determinations and magnetic studies of tetranuclear M(II)Ln(III) complexes (M = Ni, Zn; Ln = Y, Gd, Dy) involving an in situ compartmentalized schiff base ligand HL derived from the condensation of o-vanillin and 2-hydrazinopyridine as main ligand are described. Single-crystal X-ray diffraction reveals that all complexes are closely isostructural, with the central core composed of distorted {M(2)Ln(2)O(4)} cubes of the formulas [Ni(2)Ln(2)(μ(3)-OH)(2)(L)(2)(OAc)(4)(H(2)O)(3.5)](ClO(4))(2)·3H(2)O (Ln = Y 1 and Gd 2), [Ni(2)Dy(2)(μ(3)-OH)(2)(L)(2)(OAc)(5)(EtOH)(H(2)O)(1.5)](ClO(4))·EtOH·H(2)O (3) and [Zn(2)Ln(2)(μ(3)-OH)(2)(L)(2)(OAc)(5)(EtOH)(H(2)O)](ClO(4))·2EtOH·1.5H(2)O (Gd 4 and Dy 5). The Ln(III) ions are linked by two hydroxo bridges and each M(II) ion is also involved in a double phenoxo-hydroxo bridge with the two Ln(III) ions, so that each hydroxo group is triply linked to the two Ln(III) and one M(II) ions. The magnetic properties of all complexes have been investigated. Ni(2)Y(2) (1) has a ferromagnetic Ni(II)Ni(II) interaction. A weak ferromagnetic Ni(II)Ln(III) interaction is observed in the Ni(2)Ln(2) complexes (Ln = Gd 2, Dy 3), along with a weak antiferromagnetic Ln(III)Ln(III) interaction, a D zero-field splitting term for the nickel ion and a ferromagnetic Ni(II)Ni(II) interaction. The isomorphous Zn(2)Ln(2) (Ln = Gd 4, Dy 5) does confirm the presence of a weak antiferromagnetic Ln(III)Ln(III) interaction. The Ni(2)Dy(2) complex (3) does not behave as a SMM, which could result from a subtractive combination of the Dy and Ni anisotropies and an increased transverse anisotropy, leading to large tunnel splittings and quantum tunneling of magnetization. On the other hand, Zn(2)Dy(2) (5) exhibits a possible SMM behavior, where its slow relaxation of magnetization is probably attributed to the presence of the anisotropic Dy(III) ions.
- Published
- 2012
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46. The first {Dy4} single-molecule magnet with a toroidal magnetic moment in the ground state.
- Author
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Guo PH, Liu JL, Zhang ZM, Ungur L, Chibotaru LF, Leng JD, Guo FS, and Tong ML
- Abstract
A toroidal magnetic moment in the absence of a conventional total magnetic moment was first observed in a novel tetranuclear dysprosium cluster with nonmagnetic ground state. The toroidal state is quite robust with respect to variations of the exchange parameters.
- Published
- 2012
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47. Polynuclear and polymeric gadolinium acetate derivatives with large magnetocaloric effect.
- Author
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Guo FS, Leng JD, Liu JL, Meng ZS, and Tong ML
- Abstract
Two ferromagnetic μ-oxo(acetate)-bridged gadolinium complexes [Gd(2)(OAc)(2)(Ph(2)acac)(4)(MeOH)(2)] (1) and [Gd(4)(OAc)(4)(acac)(8)(H(2)O)(4)] (2) and two polymeric Gd(III) chains [Gd(OAc)(3)(MeOH)](n) (3) and [Gd(OAc)(3)(H(2)O)(0.5)](n) (4) (Ph(2)acacH = dibenzoylmethane; acacH = acetylacetone) are reported. The magnetic studies reveal that the tiny difference in the Gd-O-Gd angles (Gd···Gd distances) in these complexes cause different magnetic coupling. There exist ferromagnetic interactions in 1-3 due to the presence of the larger Gd-O-Gd angles (Gd···Gd distances), and antiferromagnetic interaction in 4 when the Gd-O-Gd angle is smaller. Four gadolinium acetate derivatives display large magnetocaloric effect (MCE). The higher magnetic density or the lower M(W)/N(Gd) ratio they have, the larger MCE they display. Complex 4 has the highest magnetic density and exhibits the largest MCE (47.7 J K(-1) kg(-1)). In addition, complex 3 has wider temperature and/or field scope of application in refrigeration due to the dominant ferromagnetic coupling. Moreover, the statistical thermodynamics on entropy was successfully applied to simulate the MCE values. The results are quite in agreement with those obtained from experimental data.
- Published
- 2012
- Full Text
- View/download PDF
48. Pure trinuclear 4f single-molecule magnets: synthesis, structures, magnetism and ab initio investigation.
- Author
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Guo FS, Liu JL, Leng JD, Meng ZS, Lin ZJ, Tong ML, Gao S, Ungur L, and Chibotaru LF
- Subjects
- Crystallography, X-Ray, Iron Compounds chemistry, Lanthanoid Series Elements chemistry, Models, Molecular, Molecular Conformation, Molecular Structure, Thermodynamics, Iron Compounds chemical synthesis, Lanthanoid Series Elements chemical synthesis, Magnetics
- Abstract
A family of linear Dy(3) and Tb(3) clusters have been facilely synthesized from the reactions of DyCl(3), the polydentate 3-methyloxysalicylaldoxime (MeOsaloxH(2) ) ligand with auxiliary monoanionic ligands, such as trichloroacetate, NO(3)(-), OH(-), and Cl(-). Complexes 1-5 contain a nearly linear Ln(3) core, with similar Ln···Ln distances (3.6901(4)-3.7304(3) Å for the Dy(3) species, and 3.7273(3)-3.7485(5) Å for the Tb(3) species) and Ln···Ln···Ln angles of 157.036(8)-159.026(15)° for the Dy(3) species and 157.156(8)-160.926(15)° for the Tb(3) species. All three Ln centers are bridged by the two doubly-deprotonated [MeOsalox](2-) ligands and two of the four [MeOsaloxH](-) ligands through the N,O-η(2)-oximato groups and the phenoxo oxygen atoms (Dy-O-Dy angles=102.28(16)-106.85(13)°; Tb-O-Tb angles=102.00(11)-106.62(11)°). The remaining two [MeOsaloxH](-) ligands each chelate an outer Ln(III) center through their phenoxo oxygen and oxime nitrogen atoms. Magnetic studies reveal that both Dy(3) and Tb(3) clusters exhibit significant ferromagnetic interactions and that the Dy(3) species behave as single-molecule magnets, expanding upon the recent reports of the pure 4f type SMMs., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2011
- Full Text
- View/download PDF
49. Chiral transition metal clusters from two enantiomeric schiff base ligands. Synthesis, structures, CD spectra and magnetic properties.
- Author
-
Fan LL, Guo FS, Yun L, Lin ZJ, Herchel R, Leng JD, Ou YC, and Tong ML
- Subjects
- Circular Dichroism, Crystallography, X-Ray, Ligands, Models, Molecular, Molecular Structure, Stereoisomerism, Magnetics, Schiff Bases chemical synthesis, Schiff Bases chemistry, Transition Elements chemistry
- Abstract
Two enantiomeric Schiff base ligands R-/S-H2L in situ generated from the condensation of o-vanillin with R- or S-2-phenylglycinol were applied to assemble chiral multinuclear transition metal magnetic clusters for the first time. Four new enantiomerically pure chiral clusters, [NaMn4(3-O)(N3)1.75Br0.25(R-L)3(MeOH)2(H2O)2][NaMn4(mu3-O)(N3)2(R-L)3(MeOH)2(H2O)2]Br4 (1R), [NaMn4(mu3-O)(N3)1.75Br0.25(S-L)3(MeOH)2(H2O)2][NaMn4(mu3-O)(N3)2(S-L)3(MeOH)2(H2O)2]Br4 (1S), [Cu6(R-L)2(R-HL)2(N3)5(MeOH)]NO3.2MeOH.H2O (2R) and [Cu6(S-L)2(S-HL)2(N3)5(MeOH)]NO3.2MeOH.H2O (2S), have been synthesized and characterized by single crystal X-ray crystallography and CD spectroscopy. Three Mn(III) in the MnIIMnIII3 clusters of 1R and 1S are joined together through the 3-O bridge to form an oxo-centered Mn3O unit. Three L2- link four manganese atoms via the mu2-O,N,O-bridging manner into a MnIIMnIII3 cluster in a distorted tetrahedral geometry. Enantiomeric 2S and 2R are hexanuclear copper(II) clusters composed of a cubane-like Cu4L4 part with a dinuclear Cu2(N3)2 unit capped on one of the faces of the Cu4L4 cubane via the mu1,1-azide and phenolate bridges from the chiral ligands. Magnetic analysis reveals intracluster antiferromagnetic interaction between adjacent manganese ions in chiral oxo-centered MnIIMnIII3 magnetic clusters for 1R and 1S, and dominating antiferromagnetic over weak ferromagnetic interactions in Cu6 clusters in 2R and 2S.
- Published
- 2010
- Full Text
- View/download PDF
50. Electron microscopic observation on a non-occluded baculo-like virus in shrimps.
- Author
-
Lu CP, Zhu S, Guo FS, and Wu SY
- Subjects
- Animals, Baculoviridae isolation & purification, Microscopy, Electron, Baculoviridae ultrastructure, Decapoda virology
- Abstract
A severe disease of farm-raised shrimp, Penaeus chinensis has spread throughout Chinese coasts since 1993. Recently, a baculo-like virus has been diagnosed as the causative agent for this epidemic disease. The electron microscopic observation of the virus is described. Thin sections of hepatopancreatic and hypodermic tissue of diseased P. chinensis showed many rod-shaped, enveloped, baculo-like virions in hypertrophied nuclei of infected cells. The virion was filled with a highly electron dense core. No occlusion bodies have been found. Negative stained intact virions, purified from infected tissues by centrifugation on sucrose discontinuous gradients, demonstrated that the viral envelops had been broken, but the cylindrical nucleocapside could be observed clearly. The nucleocapsid of average 62 nm x 314 nm was composed of a helix system of capsomers, giving rise to an open stacked ring structure and repeating approximately every third ring. The number of repeating unit was 13 to 15. We propose that the virus described here could be designated as Non-Occluded Shrimp Virus (NOSV) or Penaeus chinensis Baculo-Like Virus (PcBLV).
- Published
- 1997
- Full Text
- View/download PDF
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