2,2′-(p-Phenyl­ene)bis­(1,4,5,6-tetra­hydro­pyrimidinium) bis­[dicyanidoargentate(I)]

The asymmetric unit of the title compound, (C14H20N4)[Ag(CN)2]2, contains one-half of a centrosymmetric 2,2′-(p-phenyl­ene)bis­(1,4,5,6-tetra­hydro­pyrimidinium) (H2btb) cation and one [Ag(CN)2]− anion. In the anions, the AgI atoms adopt near linear coordination modes with the two attached cyanide groups [C—Ag—C = 173.3 (2)°]. In the crystal structure, each H2btb cation links four [Ag(CN)2]− anions via N—H⋯N hydrogen bonds into a one-dimensional ribbon

Sympathetic feedback cooling in the optomechanical system consisting of two coupled cantilevers

We present sympathetic cooling in an optomechanical system consisting of two coupled cantilevers. The hybridization of the cantilevers creates a symmetric mode, which is feedback cooled, and an anti-symmetric mode not directly controllable by the feedback. The scheme of sympathetic cooling is adopted to cool the anti-symmetric mode indirectly by parametrically coupling to the feedback-cooled symmetric mode, from which the cooling power can be transferred. Experiment shows that the realization of coherent dynamics plays an essential role in sympathetic cooling, in which optimal cooling is achieved when the mechanical dissipation rate and the strength of coupling become comparable. The sympathetic cooling is improved by increasing the strength of mode coupling to enhance the transfer of cooling power. Also, the limit of sympathetic cooling imposed by the capacity of feedback cooling is reached as the effective temperatures of the two modes approach the strong coherent coupling condition. Our research provides the prospect of extending the cooling techniques to coupled mechanical resonators for a broad application in sensing and information processing

Constraints on peculiar velocity distribution of binary black holes using gravitational waves with GWTC-3

The peculiar velocity encodes rich information about the formation, dynamics, evolution, and merging history of binary black holes. In this work, we employ a hierarchical Bayesian model to infer the peculiar velocity distribution of binary black holes for the first time using GWTC-3 by assuming a Maxwell-Boltzmann distribution for the peculiar velocities. The constraint on the peculiar velocity distribution parameter is rather weak and uninformative with the current GWTC-3 data release. However, the measurement of the peculiar velocity distribution can be significantly improved with the next-generation ground-based gravitational wave detectors. For instance, the uncertainty on the peculiar velocity distribution parameter will be measured within $\sim$ 10\% with $10^3$ golden binary black hole events for the Einstein Telescope. We, therefore, conclude that our statistical approach provides a robust inference for the peculiar velocity distribution.Comment: 15 pages, 2 figures

Study of Periplaneta Americana Microbial Community Structure and Diversity by 16S rRNA High-Throughput Sequencing

Objective: The present study probes into the microbial community structure in Periplaneta americana under different breeding conditions, using 16S rRNA high-throughput sequencing technique, in the hope of finding the microbial community structure in Periplaneta americana and their diversity under different breeding conditions. Methods: In this study, we extract the microbial metagenomic DNA of 5 groups of Periplaneta americana which under different breeding conditions. Using lllumina Miseq sequencing platform, two-terminal sequencing of V3-V4 regions of 16S rRNA were sequenced; diversity of community structure was analyzed using the softwares such as fastqc, QIIME, PyNAST, fasttree and R language.Results: Shannon index of samples in SG group was lower than that of the other four groups, significantly lower than that of DB group (P<0.05), but not significantly different from other groups. This suggested that the intake of a mixed fodder with high sugar, high fat and high protein by Periplaneta americana can reduce the diversity of microbial communities. Our findings showed that breeding intervention with different fodders may cause differences in the contents of Bacteroidetes, Proteobacteria and Firmicutes in Periplaneta americana. Results showed that long-term intake of lots of sucrose and fat may increase the proportion of Bacteroidetes in Periplaneta americana; and long-term intake of lots of sucrose may reduce the proportion of Proteobacteria in Periplaneta americana; and long-term intake of lots of fat may reduce the proportion of Firmicutes in Periplaneta americana. Two major dominant bacterial genera in all samples were Blattabacterium and Rickettsiella. But different feeding interventions can change the proportions of Blattabacterium and Rickettsiella.Conclusion: Periplaneta americana has a complex microbial community structure. Different feeding conditions may change the microbial community structure of Periplaneta americana. An important bacterial genus in Periplaneta americana, Blattabacterium is positively correlated with the intake of sucrose- and fat-rich fodder. In the breeding process of Periplaneta americana, adding sucrose and fat to fodder may increase the content and proportion of Blattabacterium in microbial communities

Directional Enhanced Probe for Side-Illumination Tip Enhanced Spectroscopy

We demonstrate a high-performance apertureless near-field probe made of a tapered metal tip with a set of periodic shallow grooves near the apex. The spontaneous emission from a single emitter near the tip is investigated systematically for the side-illumination tip enhanced spectroscopy (TES). In contrast with the bare tapered metal tip in conventional side-illumination TES, the corrugated probe not only enhances strongly local excitation field but also concentrates the emission directivity, which leads to high collection efficiency and signal-to-noise ratio. In particular, we propose an asymmetric TES tip based on two coupling nanorods with different length at the apex to realize unidirectional enhanced emission rate from a single emitter. Interestingly, we find that the radiation pattern is sensitive to the emission wavelength and the emitter positions respective to the apex, which can result in an increase of signal-to-noise ratio by suppressing undesired signal. The proposed asymmetrical corrugated probe opens up a broad range of practical applications, e.g. increasing the detection efficiency of tip enhanced spectroscopy at the single-molecule level

Demonstration of Adiabatic Variational Quantum Computing with a Superconducting Quantum Coprocessor

Adiabatic quantum computing enables the preparation of many-body ground states. This is key for applications in chemistry, materials science, and beyond. Realisation poses major experimental challenges: Direct analog implementation requires complex Hamiltonian engineering, while the digitised version needs deep quantum gate circuits. To bypass these obstacles, we suggest an adiabatic variational hybrid algorithm, which employs short quantum circuits and provides a systematic quantum adiabatic optimisation of the circuit parameters. The quantum adiabatic theorem promises not only the ground state but also that the excited eigenstates can be found. We report the first experimental demonstration that many-body eigenstates can be efficiently prepared by an adiabatic variational algorithm assisted with a multi-qubit superconducting coprocessor. We track the real-time evolution of the ground and exited states of transverse-field Ising spins with a fidelity up that can reach about 99%.Comment: 12 pages, 4 figure

MicroRNA-203 inhibits cell proliferation by repressing ΔNp63 expression in human esophageal squamous cell carcinoma

<p>Abstract</p> <p>Background</p> <p>This study was performed to investigate the effect of microRNA-203 (miR-203) and ΔNp63 on cell proliferation and the functional connection between miR-203 and ΔNp63 in ESCC.</p> <p>Methods</p> <p>We employed 2 human ESCC cell lines, Eca109 and TE-1, as the model system. The effect of miR-203 and ΔNp63 on cell proliferation was determined in cells transfected with miR-203 mimic and ΔNp63 small interfering RNA (siRNA), respectively. The regulation of ΔNp63 expression in ESCC cells by miR-203 was studied by luciferase reporter assay, RT-PCR and western blot analysis in cells transfected with miR-203. The effect of ΔNp63 re-expression on miR-203 induced inhibition of cell proliferation was studied by cell proliferation assay in cells cotransfected with miR-203 and pcDNA-ΔNp63 plasmid (without the 3'-UTR of <it>ΔNp63</it>).</p> <p>Results</p> <p>We found that both miR-203 and ΔNp63 siRNA signicantly inhibited cell proliferation in ESCC. MiR-203 could down-regulate endogenous ΔNp63 expression at the posttranscriptional level. Moreover, re-expression of ΔNp63 in cells transfected with miR-203 significantly attenuated the miR-203 induced inhibition of cell proliferation.</p> <p>Conclusions</p> <p>Our data implied that miR-203 could inhibit cell proliferation in human ESCC through ΔNp63-mediated signal pathway. Therefore, we propose that miR-203 might be used as a therapeutic agent for human ESCC.</p