Publications by authors named "Xuan Zhan"

Since Einstein's prediction regarding the existence of gravitational waves was directly verified by the ground-based detector Advanced LIGO, research on gravitational wave detection has garnered increasing attention. To overcome limitations imposed by ground vibrations and interference at arm's length, a space-based gravitational wave detection initiative was proposed, which focuses on analyzing a large number of waves within the frequency range below 1 Hz. Due to the weak signal intensity, the TMs must move along their geodesic orbit with a residual acceleration less than 10 m/s/Hz.

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Article Synopsis
  • The study explores how the structure of neural networks affects working memory (WM) function, focusing on differences in microcircuits within a WM gradient network.
  • A spiking neural network model was developed that accurately mimics WM characteristics, showing that activity during memory delays is linked to the association cortex rather than the sensory cortex.
  • Key findings include the importance of small-world structures, balance between excitation and inhibition, and circuit cycles in sustaining WM activity, highlighting the need for further research on structural gradients in the brain.
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The small molecule epiberberine (EPI) is a natural alkaloid with versatile bioactivities against several diseases including cancer and bacterial infection. EPI can induce the formation of a unique binding pocket at the 5' side of a human telomeric G-quadruplex (HTG) sequence with four telomeric repeats (Q4), resulting in a nanomolar binding affinity ( approximately 26 nM) with significant fluorescence enhancement upon binding. It is important to understand (1) how EPI binding affects HTG structural stability and (2) how enhanced EPI binding may be achieved through the engineering of the DNA binding pocket.

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Mercury (Hg) is known to affect aquatic, terrestrial ecosystems as well as human health, through biomagnification. Mangrove wetlands are potential Hg sinks because of their low tidal velocity, fast sedimentation rate, strong reducing condition and high organic matter content. The spatial and temporal distribution of Hg has been a hot topic of recent studies in mangrove wetlands.

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Over the past decade, dynamic schemes have been proposed for the use of bistable systems in the design of logic devices. A bistable system in a noisy background can operate as a reliable logic gate in a moderate noise level, which is called a logical stochastic resonance (LSR). In this paper, we theoretically explore the emergence of LSR in general bistable systems and identify the dynamical mechanisms of LSR.

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The direct coupling of aldehydes with petrochemical feedstock alkenes and alkynes would represent a practical and streamlined approach for allylation and allenylation chemistry. However, conventional approaches commonly require preactivated substrates or strong bases to generate allylic or propargylic carbanions and only afford branched allylation or propargylation products. Developing a mild and selective approach to access synthetically useful linear allylation and allenylation products is highly desirable, albeit with formidable challenges.

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There have been few reports on the substituent effect of main-group-element corrole complexes as ligand-centered homogeneous electrocatalysts for the hydrogen evolution reaction (HER). The key to comprehend the catalytic mechanism and develop efficient catalysts is the elucidation of the effects of electronic structure on the performance of energy-related small molecules. In this work, the "push-pull" electronic effect of the substituents on electrocatalytic HER of phosphorus corroles was investigated by using 5,10,15-tris(phenyl) corrole phosphorus (1P), 10-pentafluorophenyl-5,15-bis(phenyl) corrole phosphorus (2P), 10-phenyl-5,15-bis(pentafluorophenyl) corrole phosphorus (3P), 5,10,15-tris(pentafluorophenyl) corrole phosphorus (4P) complexes bearing hydroxyl axial ligands and different numbers of fluorine atoms on the meso-aryl substituents.

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With the evolution of the pandemic caused by the Coronavirus disease of 2019 (COVID-19), reverse transcriptase-polymerase chain reactions (RT-PCR) have invariably been a golden standard in clinical diagnosis. Nevertheless, the traditional polymerase chain reaction (PCR) is not feasible for field application due to its drawbacks, such as time-consuming and laboratory-based dependence. To overcome these challenges, a microchip-based ultrafast PCR system called SWM-02 was proposed to make PCR assay in a rapid, portable, and low-cost strategy.

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The economical consideration of using an electrocatalyst in energy-related field, composed of non-precious/sustainable elements is quite noteworthy. In this work, the phosphorus(V) complex of tris-(pentafluorophenyl)corrole [(TPFC)P (OH) ] was reported as electrocatalyst for the hydrogen evolution reaction (HER). The electrochemical studies revealed that the HER experienced a ECEC pathway (E: electron transfer step, C: chemical step), and the possible intermediate [P ]-H species was suggested.

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Background: Corona virus disease 2019 (COVID-19) is a severe acute respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Different pooling testing strategies have been applied for the detection of SARS-CoV-2. However, the discrepancies among different pooling strategies are still to be explored.

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RNAs form secondary structures containing double-stranded base paired regions and single-stranded regions. Probing, detecting and modulating RNA structures and dynamics requires the development of molecular sensors that can differentiate the sequence and structure of RNAs present in viruses and cells, as well as in extracellular space. In this review, we summarize the recent progress on the development of chemically modified peptide nucleic acids (PNAs) for the selective recognition of double-stranded RNA (dsRNA) sequences over both single-stranded RNA (ssRNA) and double-stranded DNA (dsDNA) sequences.

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A set of gold corrole complexes containing four different β-substituent groups (Br/I/CF), namely, , , and , were investigated; all showed room temperature phosphorescence. The phosphorescence quantum yields of the corroles were determined using tetraphenylporphyrin as a reference: Φ (, 0.75%) > Φ (, 0.

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Main group chemistry is often considered less "dynamic" than transition metal (TM) chemistry because of predictable VSEPR-based central atom geometries, relatively slower redox switching and lack of electronic d-d transitions. However, we delineate what has been made possible with main group chemistry to give it its proper due and up-to-date treatment. The huge untapped potential regarding photophysical properties and functioning hereby spurred us to review a range of corrole reports addressing primarily photophysical trends, synthetic aspects, and important guidelines regarding substitution and inorganic principles.

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Background: Liquid-phase concentrated growth factor (LPCGF), a new-generation platelet concentrate, may potently stimulate human periodontal ligament (PDL) cells. This study assessed the effectiveness of ethylenediaminetetraacetic acid (EDTA) and/or LPCGF on periodontally diseased root surfaces through their effects on PDL cells.

Methods: Dentin blocks prepared from periodontal teeth were divided into four groups and treated as follows: group I, scaling and root planning (SRP); group II, SRP + EDTA; group III, SRP + LPCGF; and group IV, SRP+EDTA + LPCGF.

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Toluene, p-xylene and mesitylene were cleanly converted to their corresponding monoaldehydes via mild photooxygenation utilizing transition metal and main group β-CF-substituted corroles. Aldehyde yield increased as more electron-donating CH groups are present on the substrate. 4-P was most efficient (TON ∼ 1072, mesitylene) via the singlet oxygen vis the superoxide mechanism.

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Objective: To examine the gender, age, and region of residence in the anthropometric and nutritional profiles of children and adolescents aged 6-18 in Henan Province, China's third most populous province.

Design: This cross-sectional study of the China National Nutrition and Health survey (2010-2013) used a multistage cluster sampling technique. The sample included Chinese schoolchildren and adolescents aged 6 to 18 years (1,660 boys and 1,561 girls).

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Article Synopsis
  • The study analyzed the height, weight, and BMI of children and adolescents aged 6-17 in Henan Province from 2010 to 2013, involving 3,221 participants through random sampling from various urban and rural areas.
  • Results showed that urban students generally exhibited better growth compared to rural students, though the BMI gap between these areas was decreasing.
  • The analysis highlighted significant malnutrition issues, particularly in rural students, with a noted prevalence of obesity in urban areas, especially among younger primary school children.
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Neuron shows distinct dependence of electrical activities on membrane patch temperature, and the mode transition of electrical activity is induced by the patch temperature through modulating the opening and closing rates of ion channels. In this paper, inspired by the physical effect of memristor, the potassium and sodium ion channels embedded in the membrane patch are updated by using memristor-based voltage gate variables, and an external stimulus is applied to detect the variety of mode selection in electrical activities under different patch temperatures. It is found that each ion channel can be regarded as a physical memristor, and the shape of pinched hysteresis loop of memristor is dependent on both input voltage and patch temperature.

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We successfully fabricated the long-period fiber gratings in few-mode fibers (FMF-LPFGs) with micro-tapered method, which are different from the traditional LPFGs that only couple the fundamental mode to different cladding modes to obtain multiple resonant dips. There are two resonant dips on the transmission spectrum of the FMF-LPFGs, which are induced by the coupling between the fundamental mode and the low-order cladding mode LP (dip 1) and the coupling between the fundamental mode and the high-order core mode LP (dip 2). Due to the difference of the coupling mechanism involved in two dips, the shift of resonant wavelengths has different characteristics with the variation of the external environment parameter.

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As the global population ages, searching for drugs and functional foods which can slow down the aging process has attracted a number of researchers. In this paper, the Lycium barbarum polysaccharides (LBP) extracted from Lycium barbarum was characterized and the effects of LBP on the aging and health of were studied. Results showed that LBP can prolong the lifespan, improve the abilities to withstand environmental stress, enhance reproductive potentials, and maintain muscle integrity of .

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  • Researchers synthesized new gallium and aluminum corrole compounds with multiple trifluoromethyl groups using a simple one-pot method, setting the stage for further studies in inorganic photocatalysis.
  • These compounds showed red shifts in their absorption and emission spectra due to the CF group substitution and demonstrated strong fluorescence, particularly 3CF-Al, which had the highest fluorescence quantum yield (0.71).
  • The photocatalytic performance of these complexes indicated that tris-trifluoromethylation significantly enhances catalytic activity, with 3CF-Ga outperforming others in producing bromophenol and benzylbromide, exhibiting high turn-over numbers in both reactions.
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Although the affinity of metallocorroles to axial ligands is quite low, this is not the case when the chelated element is phosphorus. This work is hence focused on the mechanism of ligand exchange of six-coordinate phosphorus corroles as a tool for affecting their chemical and physical properties. These fundamental investigations allowed for the development of facile methodologies for the synthesis of a large series of complexes and the establishment of several new structure/activity profiles that may be used to understand and predict spectroscopic features and for tailor-made modification of photophysical and electrochemical properties.

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In order to study the effect of -iodination of free-base corroles on their photophysical character, we designed and synthesized a series of free-base corrole derivatives F10-OH (iodine-free), F10-OH-I (mono-iodo) and F10-OH-2I (di-iodo), with different substitution patterns at the -position as candidates for photodynamic therapy (PDT). We employed several optical spectroscopic techniques, including time-resolved spectroscopy from a femtosecond to microsecond and singlet oxygen luminescence to study the properties of excited singlet and triplet states, as well as the singlet oxygen quantum yields. The sub-picosecond internal conversion, ∼1 ps intramolecular vibrational energy redistribution, tens of ps vibrational cooling, are similar across the three corroles.

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An eight-member series of CF-substituted difluorophosphorus corroles was prepared for establishing a structure-activity profile of these high-potential photosensitizers. It consisted of preparing all four possible isomers of the monosubstituted corrole and complexes with 2-, 3-, 4-, and 5-CF groups on the macrocycle's periphery. The synthetic pathway to these CF-substituted derivatives, beginning with (tpfc)PF, involves two different initial routes: (i) direct electrophilic CF incorporation using FSOCFCOMe and copper iodide, or (ii) bromination to achieve the 2,3,8,17,18-pentabrominated compound using excess bromine in methanol.

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Rhodium insertion into the new 5,10,15,20-tetrakis(trifluoromethyl)sapphyrin was found to be much more facile than for other analogues, owing to NH⋅⋅⋅F hydrogen-bonding interactions that stabilise the pyrrole-inverted structure characteristic of the metallated product. The thus-obtained rhodium(I) complexes have axial chirality, and the enantiomers were resolved. The latter were found to interconvert quite rapidly in a process that involves a tautomerisation-like movement of the metal fragment between the five N atoms.

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