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A silylene-stabilized distannavinylidene with a highly labile substituent

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Science China Chemistry 2023年第12期66卷 3555-3561页

作者： Zihao qiao Ming chen Zhenbo Mo State Key Laboratory and Institute of Elemento-Organic Chemistry Frontiers Science Center for New Organic MatterCollege of ChemistryNankai UniversityTianjin 300071China

Vinylidene and its heavier analogues are fundamentally important in synthetic chemistry,but their stabilization and structural characterization remains extremely challenging.Herein we describe that the reduction of an NHSi-stabilized stannyl-stannylene(2)with one molar equivalent of[(^(Mes)Nacnac)Mg]_(2)affords an NHSi-stabilized distannavinylidene(3).Single-crystal X-ray crystallography and density functional theory(DFT)calculations show that compound 3 features a pronounced Sn=Sn double bond and one lone pair of electrons at the two-coordinate Sn atom.Most strikingly,3 undergoes an interconversion with distannyne(4)upon the addition and removal of one molar equivalent of N-heterocyclic carbene.Compound 3 readily reacts with Ph_(2)C=C=O,Ad C≡P and(Al Cp^(*))_(4)to give the structurally interesting stannacycles(5,6)and an aluminyl distannyne(7),demonstrating its unique reactivity derived from the high substituent lability.

关键词： distannavinylidene silylenes stannacycles distannyne carboranes

A pilot exploration with Posiphen to normalize amyloid precursor protein in Down syndrome

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Neural Regeneration Research 2021年第12期16卷 2420-2421页

作者： Xu-qiao Chen Department of Neurosciences University of California San DiegoLa JollaCAUSA

Down syndrome(DS)pathology:DS is the most common cause of Alzheimer’s disease(AD)and has a known AD-causing genetic variation which is trisomy of the whole or part of Homo sapiens chromosome 21(HSA21)(chen and Mobley,2019a).Compared with AD,DS usually present with various symptoms and manifestations which are related to dysfunction of multiple body systems;the extra copies of the many genes present in HSA21 in DS can cause various developmental problems including neurodevelopmental deficits,which underlie the physical features in DS and may also contribute to the ADrelated neurological symptoms of DS like cognition decline(Antonarakis et al.,2020).

关键词： al. amyloid pathology

Chloride-intercalated continuous chemical vapor deposited graphene film with discrete adlayers

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Nano Research 2018年第1期11卷 440-448页

作者： qiao Chen Li Zhang Hongwei Zhu State Key Lab of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing 100084 China Center for Nano and Micro Mechanics Tsinghua University Beijing 100084 China

Heteroatom doping can open the bandgap and increase the carrier density, thus extending the applications of graphene. Iron chloride （FeC13） intercalation has proven to be an efficient method for the heavy doping of graphene. In this study, we prepared continuous chemical vapor deposited graphene （CVD-G） consisting of hexagonal adlayer domains to study the FeC13 intercalation. The structure of the FeC13-treated CVD-G was easily characterized via atomic force microscopy because of the change in the interlayer distance. FeC13 crystals several nanometers thick were integrated with the graphene surface, and FeC13 layer flakes were intercalated between the CVD-G adlayers. The G-band position and two-dimensional band shape in the Raman spectra confirmed the intercalation of the FeC13 between the graphene layers. The FeCI~ intercalation increased the electrical conductivity of the CVD-G with a well-maintained transmittance, which could be beneficial for a sensitive photodetector.

关键词： intercalation,graphene,chemical vapor deposition,iron chloride

Involvement of T-complex protein 1-ring complex/chaperonin containing T-complex protein 1(TRiC/CCT) in retrograde axonal transport through tau phosphorylation

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Neural Regeneration Research 2019年第4期14卷 588-590页

作者： Xu-qiao Chen Department of Neurosciences University of California San Diego

The cytosolic chaperonin T-complex protein 1-ring complex(TRiC)or chaperonin containing T-complex protein 1(CCT)is essential in de novo folding of approximately 10%of the eukaryotic,newly translated polypeptides as well as misfolded proteins.There is a close link between the TRiC/CCT cytosolic chaperonin and neurodegenerative diseases(Lopez et al.,2015).A lot of research suggests that CCT plays neuroprotective roles in neurodegenerative diseases including Huntington’s disease(Lopez et al.,2015).Either overexpression of a single or all eight subunits(CCT1-8)or treatment of the substrate-binding apical domain of yeast CCT1(ApiCCT1)prevented mutant Huntingtin aggregation and improved cellular and neuronal functions(Zhao et al.,2016).Importantly,our recent study has demonstrated that both CCT and ApiCCT could reduce mutant Huntingtin level and enhance both anterograde and retrograde axonal transport of brain-derived neurotrophic factor.These results led to restoration of the trophic status of striatal neurons from a bacterial artificial chromosome transgenic mouse model of Huntington’s disease(Zhao et al.,2016).Axonal transport is regulated by many factors including microtubule-associated protein tau,which promotes tubulin polymerization and stabilizes microtubules.Impaired interaction between tau and microtubules plays a vital role in the pathogenesis of multiple neurodegenerative diseases(Wang and Mandelkow,2016).Interestingly,tau phosphorylation is also observed in brains of several Huntington’s disease mouse models and Huntington’s disease patients(Gratuze et al.,2016).In a recent study,we explored if CCT subunit has any effect on axonal transport in a tau-dependent pathway(chen et al.,2018b).We focused on the retrograde axonal transport of brain-derived neurotrophic factor,as neurotrophic factor-mediated signaling in the form of signaling endosome is essential in both the developing and the mature nervous system and dysregulation of trafficking of neurotrophic factors is tightly linked to disorders of the nervou

关键词： T-complex protein 1-ring complex(TRiC) chaperonin containing T-complex protein 1(CCT) Involvemen

Charge transfer complex enabled photoreduction of ether phosphonium salts for the selective oxyalkylation of enamides

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Chinese Chemical Letters 2024年第2期35卷 411-414页

作者： Sen qiao Kunquan chen Qiang Liu Zhixiang Wang Xiangyu chen School of Chemical Sciences University of the Chinese Academy of SciencesBeijing 100049China Binzhou Institute of Technology Weiqiao-UCAS Science and Technology ParkBinzhou 256606China

A charge transfer complex(CTC)-enabled photoreduction of ether phosphonium salts for the generation of oxyalkyl radicals was described.The photoreduction provides a convenient method to achieve selective oxyalkylation of enamides with broad substrate scope.The method features operational simplicity,mild and inherent green conditions.

关键词： Enamides Phosphonium salts Ethers Charge transfer complex Visible light

New insights into the effects of APP gene dose on synapse in Down syndrome

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Neural Regeneration Research 2024年第5期19卷 961-962页

作者： Xu-qiao Chen Xinxin Zuo Department of Neurosciences University of California San DiegoLa JollaCAUSA

Synaptic dysfunction:Alzheimer’s disease(AD)is a prevalent form of dementia,affecting over 35 million people worldwide(Tzioras et al.,2023).A synapse serves as the connection point between neurons,facilitating the transmission of information from one neuron to another.Dynamic alterations in synapses,known as synaptic plasticity,play a pivotal role in cognitive processes such as learning and memory.Synaptic loss has been identified as a key contributor to cognitive decline in AD patients.Studies have shown that the soluble forms of amyloid-beta(Aβ)and tau proteins are toxic to synapses,leading to cognitive impairment in animal models(Spires-Jones and Hyman,2014).Additionally,the formation of oligomers of tau and Aβcan spread pathology through synaptic connections in the brain,emphasizing the vital role of synapses in disease progression.

关键词： alterations Aβ tau

PhotoNs-GPU:A GPU accelerated cosmological simulation code

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Research in Astronomy and Astrophysics 2021年第11期21卷 98-104页

作者： qiao Wang chen Meng Key Laboratory for Computational Astrophysics National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China

We present a GPU-accelerated cosmological simulation code,PhotoNs-GPU,based on an algorithm of Particle Mesh Fast Multipole Method(PM-FMM),and focus on the GPU utilization and optimization.A proper interpolated method for truncated gravity is introduced to speed up the special functions in kernels.We verify the GPU code in mixed precision and different levels of the interpolated method on GPU.A run with single precision is roughly two times faster than double precision for current practical cosmological simulations.But it could induce an unbiased small noise in power spectrum.Compared with the CPU version of PhotoNs and Gadget-2,the efficiency of the new code is significantly improved.Activated all the optimizations on the memory access,kernel functions and concurrency management,the peak performance of our test runs achieves 48%of the theoretical speed and the average performance approaches to~35%on GPU.

关键词： methods:numerical cosmology:theory large-scale structure of universe

Luminescence of samarium doped hydroxyapatite containing strontium:Effects of doping concentration

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Journal of Rare Earths 2022年第3期40卷 398-405,I0002页

作者： Pu chen Fen Wang Yinpo qiao Zhen Zhang Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials School of Materials Science and EngineeringShaanxi University of Science and TechnologyXi'an 710021China

A series of samarium(Sm)doped hydroxyapatites containing strontium(Sr)with controllable and adjustable luminescence were designed and prepared via chemical hydrolysis co-precipitation method.The effects of doping concentration of Sm on the structure,composition,photoluminescence(PL),energy transfer,substitute site,fluoresce lifetime and luminescence color of samples were investigated.It is shown that the introduction of Sr ions induces the structure and composition change for Sm doped samples.The typical transitions of Sm^(3+) at 564,601,648 and 707 nm due to^(4)G_(5/2)→^(6)H_(J/2)(J=5,7,9 and 11)transition under the excitation of 404 nm were detected.The PL intensity is affected by the Sr/Ca ratio and Sm concentration,and the optimal concentration of Sm is 0.8 mol%when Sr/Ca ratio equals 7/3.The non-radiative transitions and energy transfer of Sm ions are the main reason for the quenching,and the interactions among ions are ascribed to dipole-dipole type by theoretical calculation.Besides,the ratio of PL intensity between 601 and 648 nm(r_(O/R)=I_(601nm)/I_(648nm))indicates the symmetry and substitution process of Sm ions to Ca/Sr ions.The fluorescence lifetime(τ)decreases with the concentration of Sm increasing,which is the result of the decrease of distance and the enhanced interaction between Sm ions.The CIE chromaticity coordinates and luminescence color of samples are in the orange-red region and have close relation with the concentration of Sm.Furthermore,the cytotoxicity evaluation and confocal laser scanning microscopy(CLSM)observation of samples via cells indicate the good biocompatibility and safe use of this kind of bio-based luminescent materials for their potential efficient fluorescence labeling and detection.

关键词： Samarium Strontium Hydroxyapatite Photo-luminescence Energy transfer Cytotoxicity evaluation

A biepitope,adjuvant-free,self-assembled influenza nanovaccine provides cross-protection against H3N2 and H1N1 viruses in mice

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Nano Research 2022年第9期15卷 8304-8314页

作者： Yongbo qiao YaXin Zhang Jie chen Shenghui Jin Yarning Shan National Engineering Laboratory for AIDS Vaccine School of Life SciencesJilin UniversityChangchun 130012Chin

Currently,the incorporation of multiple epitopes into vaccines is more desirable than the incorporation of a single antigen for universal influenza vaccine development.However,epitopes induce poor immune responses.Although the use of adjuvants can overcome this obstacle,it may raise new problems.Effective antigen delivery vehicles that can function as both antigen carriers and intrinsic adjuvants are highly desired for vaccine development.Here,we report a biepitope nanovaccine that provides complete protection in mice against H3N2 virus as well as partial protection against H1N1 virus.This vaccine(3MCD-f)consists of two conserved epitopes(matrix protein 2 ectodomain(M2e)and CDhelix),and these epitopes were presented on the surface of ferritin in a sequential tandem format.Subcutaneous immunization with 3MCD-f in the absence of adjuvant induces robust humoral and cellular immune responses.These results provide a proof of concept for the 3MCD-f nanovaccine that might be an ideal candidate for future influenza pandemics.

关键词： influenza universal vaccine multi-epitope nanovaccine