Efficient regioselective addition of β-diketones to styrenes, norbornene, cyclic enol ether, and diene has been realized by means of copper(II) triflate as the catalyst. The solvent effect is ...prominent on the reactions, and the desired addition products were obtained in good to excellent yields only in dioxane or ionic liquid bmimPF6. The mechanism suggests that copper(II) triflate activates the enolic O−H bond of a β-diketone substrate to initiate the addition reaction.
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X-ray generation via synchrotron radiation and bremsstrahlung in the interaction of short laser pulses with a solid target is of much current interest owing to its numerous applications. The ...efficiency of laser to X-ray energy conversion is thus a crucial factor. We found that the energy conversion efficiency of synchrotron radiation and bremsstrahlung is mainly governed by the ratio of the laser pulse width to the preplasma width, which is in turn governed by the laser profile, intensity, and spot size. Synchrotron radiation dominates when the ratio is less than unity, otherwise bremsstrahlung dominates. The type of radiation can thus be controlled by tailoring the laser parameters.
In order to study the laser plasma instabilities (LPIs) in the context of some novel six-side laser-driven indirect designs like the six-cylinder-port hohlraum and the three-axis cylindrical ...hohlraum, where the laser beams inject in hohlraum with a large angle. LPI experiments in cylindrical hohlraum with only outer beams were designed and performed based on the current laser arrangement condition of SGIII laser facility for the first time. Stimulated Brillouin backscatter (SBS) was found to be the dominant instability with high instantaneous reflectivity in experiments. A typical feature was obtained in the time-resolved spectra of SBS, which maintained similar for different laser intensities of the interaction beam. The experimental data are analyzed by the hydrodynamic simulations combined with HLIP code, which is based on the ray-tracing model. By analysis of experimental data, it is argued that the mixture of gas and Au in the region of their interface is important to SBS, which indicates the need for the mixture model between the filled gas and the high Z plasma from hohlraum wall in the hydrodynamic simulations. Nonlinear saturation of SBS as well as the smoothed beam are also discussed here. Our effective considerations of the ions pervasion effect and the smoothed beam provide utilitarian ways for improvement of the current ray-tracing method.
Three-dimensional particle-in-cell simulations show that relativistic Gaussian laser light can be transformed into relativistic vortex laser light with axial orbital angular momentum (OAM) as it ...propagates through a homogeneous spiral-profiled low-density plasma slab. In the process, the plane equiphase surfaces of the Gaussian laser undergo azimuthal modulation and become a continuous helical surface. The intensity profile of the laser changes from maximum-on-axis to donut-shaped. Because of the azimuthally varying slab thickness, the laser ponderomotive and the charge-separation forces exert a torque on the plasma when it passes through it, resulting in the creation of oppositely directed OAM in the plasma ions and the laser light, with the electrons remaining nearly OAM free. The proposed scheme can be used to generate both single- and multi-mode relativistic vortex lasers propagating along the direction of the input laser, which is especially convenient for many applications.
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A newly developed relativistic Vlasov code is introduced. The governing Vlasov-Maxwell equation system is solved numerically in one-dimensional space and three-dimensional momentum space. Spherical ...coordinate system is adopted to characterize the momentum variables for its potential advantage on reducing computational cost. The resulting Vlasov equation is split into two advection equations with respect to position and momentum, respectively. They are solved with a conservative finite volume scheme, together with techniques suppressing numerical oscillations at sharp interfaces. Relativistic longitudinal plasma oscillations are investigated for different plasma temperatures and wave numbers. Results from code simulations are in good agreement with the existing theories.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
An efficient one-pot route to unsymmetrical diorganyl selenides has been developed by ruthenium(III) chloride catalyzed reactions of dibenzyl or diphenyl diselenides with alkyl halides in the ...presence of zinc. Organic iodides, bromides, and activated chlorides underwent the reactions efficiently. Unreactive organic chlorides also underwent the same type of selenation with sodium bromide as the additive.
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Nucleotide excision repair functions to protect genome integrity, and ongoing studies using excision repair sequencing (XR-seq) have contributed to our understanding of how cells prioritize repair ...across the genome. In this method, the products of excision repair bearing damaged DNA are captured, sequenced, and then mapped genome-wide at single-nucleotide resolution. However, reagent requirements and complex procedures have limited widespread usage of this technique. In addition to the expense of these reagents, it has been hypothesized that the immunoprecipitation step using antibodies directed against damaged DNA may introduce bias in different sequence contexts. Here, we describe a newly developed adaptation called dA-tailing and adaptor ligation (ATL)–XR-seq, a relatively simple XR-seq method that avoids the use of immunoprecipitation targeting damaged DNA. ATL-XR-seq captures repair products by 3′-dA-tailing and 5′-adapter ligation instead of the original 5′- and 3′-dual adapter ligation. This new approach avoids adapter dimer formation during subsequent PCR, omits inefficient and time-consuming purification steps, and is very sensitive. In addition, poly(dA) tail length heterogeneity can serve as a molecular identifier, allowing more repair hotspots to be mapped. Importantly, a comparison of both repair mapping methods showed that no major bias is introduced by the anti-UV damage antibodies used in the original XR-seq procedure. Finally, we also coupled the described dA-tailing approach with quantitative PCR in a new method to quantify repair products. These new methods provide powerful and user-friendly tools to qualitatively and quantitatively measure excision repair.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
8-Oxo-7,8-dihydro-2′-deoxyguanosine (OG), one of the most common oxidative DNA damages, causes genome instability and is associated with cancer, neurological diseases and aging. In addition, ...OG and its repair intermediates can regulate gene transcription, and thus play a role in sensing cellular oxidative stress. However, the lack of methods to precisely map OG has hindered the study of its biological roles. Here, we developed a single-nucleotide resolution OG-sequencing method, named CLAPS-seq (Chemical Labeling And Polymerase Stalling Sequencing), to measure the genome-wide distribution of both exogenous and endogenous OGs with high specificity. Our data identified decreased OG occurrence at G-quadruplexes (G4s), in association with underrepresentation of OGs in promoters which have high GC content. Furthermore, we discovered that potential quadruplex sequences (PQSs) were hotspots of OGs, implying a role of non-G4-PQSs in OG-mediated oxidative stress response.
In this study, we propose two full-optical-setup and single-shot measurable approaches for complete characterization of attosecond pulses from surface high harmonic generation (SHHG): SHHG-SPIDER ...(spectral phase interferometry for direct electric field reconstruction) and SHHG-SEA-SPIDER (spatially encoded arrangement for SPIDER). 1D- and 2D-EPOCH PIC (particle-in-cell) simulations were performed to generate the attosecond pulses from relativistic plasmas under different conditions. Pulse trains dominated by single isolated peak as well as complex pulse train structures are extensively discussed for both methods, which showed excellent accuracy in the complete reconstruction of the attosecond field with respect to the direct Fourier transformed result. Kirchhoff integral theorem has been used for the near-to-far-field transformation. This far-field propagation method allows us to relate these results to potential experimental implementations of the scheme. The impact of comprehensive experimental parameters for both apparatus, such as spectral shear, spatial shear, cross-angle, time delay, and intensity ratio between the two replicas has been investigated thoroughly. These methods are applicable to complete characterization for SHHG attosecond pulses driven by a few to hundreds of terawatts femtosecond laser systems.
Type I interferons (IFN-Is) play an important role in the antiviral immune response in teleost fishes. In this study, one type I interferon (bcIFNb) from black carp (Mylopharyngodon piceus) has been ...cloned and characterized. The full-length cDNA of bcIFNb gene consists of 806 nucleotides and the predicted bcIFNb protein contains 188 amino acids. Basing on the cysteine number and evolutionary position, bcIFNb was classified into group II type I IFN. q-PCR analysis demonstrated that bcIFNb mRNA level varied in vivo and ex vivo in response to different stimuli. bcIFNb was detected in both the whole cell lysate and the supernatant media of HEK293T cells or EPC cells transfected with bcIFNb through immunoblot assay. IFN stimulated genes (ISGs) were greatly upregulated when the host cells were treated with the bcIFNb-containing conditioned media. EPC cells showed greatly enhanced antiviral ability when the cells were transfected with bcIFNb or treated with the bcIFNb-containing conditioned media before GCRV or SVCV infection. Glycosidase digestion analysis determined that bcIFNb was modified with N-linked glycosylation, which occurred on the Asn (N) of 92 site of this cytokine. The un-glycosylated mutant bcIFNb-N92Q presented the similar antiviral ability as that of wild type bcIFNb, which demonstrated that N-linked glycosylation did not contribute directly to the antiviral property of this fish cytokine.
•bcIFNb was classified into group II type I IFN.•bcIFNb was an antiviral cytokine against GCRV and SVCV.•bcIFNb was modified with N-linked glycosylation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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