Twist-3 light-cone distribution amplitudes of the scalar mesons within the QCD sum rules and their application to the B→SB \to S transition form factors

We investigate the twist-3 light-cone distribution amplitudes (LCDAs) of the scalar mesons $a_0$, $K^{\ast}_0$ and $f_0$ within the QCD sum rules. The QCD sum rules are improved by a consistent treatment of the sizable $s$-quark mass effects within the framework of the background field approach. Adopting the valence quark component $(\bar{q}_1 q_2)$ as the dominant structure of the scalar mesons, our estimation for their masses are close to the measured $a_0(1450)$, $K^{\ast}_0(1430)$ and $f_0(1710)$. From the sum rules, we obtain the first two non-zero moments of the twist-3 LCDAs $\phi^{s,\sigma}_{a_0}$: $\langle \xi_{s,a_0}^{2(4)} \rangle=0.369 \;(0.245)$ and $\langle \xi_{\sigma,a_0}^{2(4)} \rangle=0.203 \;(0.093)$; those of the twist-3 LCDAs $\phi_{K^*_0}^{s,\sigma}$: $\langle \xi_{s,K^{\ast}_0}^{1(2)} \rangle =0.004\;(0.355)$ and $\langle \xi_{\sigma,K^{\ast}_0}^{1(2)} \rangle =0.018\;(0.207)$; and those of the twist-3 LCDAs $\phi_{f_0}^{s,\sigma}$: $\langle \xi_{s,f_0}^{2(4)} \rangle=0.335 \;(0.212)$ and $\langle \xi_{\sigma,f_0}^{2(4)} \rangle=0.196 \; (0.088)$, respectively. As an application of those twist-3 LCDAs, we study the $B \to S$ transition form factors by introducing proper chiral currents into the correlator, which is constructed such that the twist-3 LCDAs give dominant contribution and the twist-2 LCDAs make negligible contribution. Our results of the $B \to S$ transition form factors at the large recoil region $q^2 \simeq 0$ are consistent with those obtained in the literature, which inversely shows the present twist-3 LCDAs are acceptable.Comment: 14 pages, 12 figures, 7 table

Crystal engineered acid–base complexes with 2D and 3D hydrogen bonding systems using p-hydroxybenzoic acid as the building block

p-Hydroxybenzoic acid (p-HOBA) was selected as the building block for self-assembly with five bases, i.e., diethylamine, tert-butylamine, cyclohexylamine, imidazole and piperazine, and generation of the corresponding acid–base complexes 1–5. Crystal structure analyses suggest that proton-transfer from the carboxyl hydrogen to the nitrogen atom of the bases can be observed in 1–4, while only in 5 does a solvent water molecule co-exist with p--HOBA and piperazine. With the presence of O–H···O hydrogen bonds in 1–4, the deprotonated p-hydroxybenzoate anions (p-HOBAA–) are simply connected each other in a head-to-tail motif to form one-dimensional (1D) arrays, which are further extended to distinct two-dimensional (2D) (for 1 and 4) and three-dimensional (3D) (for 2 and 3) networks via N–H···O interactions. While in 5, neutral acid and base are combined pair-wise by O–H···N and N–H···O bonds to form a 1D tape and then the 1D tapes are sequentially combined by water molecules to create a 3D network. Some interlayer or intralayer C–H···O, C–H···p and p×××p interactions help to stabilize the supramolecular buildings. Melting point determination analyses indicate that the five acid–base complexes are not the ordinary superposition of the reactants and they are more stable than the original reactants

4-(3-Carb­oxy­phen­yl)pyridinium nitrate

In the title salt, C12H10NO2 +·NO3 −, the dihedral angle between the pyridine ring and the benzene ring of the 4-(3-carb­oxy­phen­yl)pyridinium cation is 30.14 (2)°. Inversion-related pairs of cations are linked into dimers by pairs of O—H⋯O hydrogen bonds. Pairs of dimers are linked by N—H⋯O and C—H⋯O hydrogen bonds involving nitrate anions as acceptors, generating supra­molecular chains along the diagonal of the bc plane

Structural Characteristics and Driving Factors of the Planktonic Eukaryotic Community in the Danjiangkou Reservoir, China

Planktonic eukaryotes are widespread in aquatic ecosystems, and the study of their community composition and driving factors is of great significance to protecting and maintaining the balance of these ecosystems. This study evaluates five typical ecological sites in the Danjiangkou Reservoir—the water source for the project. This was done to comprehensively understand the composition of Danjiangkou Reservoir planktonic eukaryotes, and ensure the ecological balance of the water source for the South-to-North Water Diversion Project. The diversity of the planktonic eukaryotes in surface water and the factors driving changes in their abundance are analyzed with an 18S ribosomal DNA sequencing approach. Monitoring shows that the Danjiangkou Reservoir has good water quality. The Danjiangkou Reservoir planktonic eukaryote community is mainly composed of 11 phyla, of which Cryptomonadales is dominant, accounting for an average percentage of 65.19% of the community (47.2–84.90%). LEFSe analysis shows significant differences among samples in the abundances of 13 phyla, 20 classes, 23 orders, 26 families, and 27 genera, and there are also significant differences in the diversity of planktonic eukaryotes at different temporal and spatial scales. Redundancy analysis (RDA) show that water temperature, DO, SD, TN, and Chla are significant factors that affect the composition of the planktonic eukaryote community. Spearman rank correlation analysis combined with taxonomic difference analysis shows that Kathablepharidae and Choanoflagellida are not sensitive to environmental or physicochemical factors and that the interannual variations in their abundance are not significant. Network analysis shows that Protalveolata, Basidiomycota, P1-31, Bicosoecida, and Ochrophyta represent important nodes in the single-factor network, while Chytridiomycota, P1-31, Cryptomycota, Ochrophyta, Ichthyosporea, Bicosoecida, Protalveolata, and physicochemical factors (ORP, TN, WT, DO, SD, NH3-N, and NO3-N) represent important nodes in the two-factor network

Revisiting the quantum Szilard engine with fully quantum considerations

By considering level shifting during the insertion process we revisit the quantum Szilard engine (QSZE) with fully quantum consideration. We derive the general expressions of the heat absorbed from thermal bath and the total work done to the environment by the system in a cycle with two different cyclic strategies. We find that only the quantum information contributes to the absorbed heat, and the classical information acts like a feedback controller and has no direct effect on the absorbed heat. This is the first demonstration of the different effects of quantum information and classical information for extracting heat from the bath in the QSZE. Moreover, when the well width $L\rightarrow \infty$ or the temperature of the bath $T\rightarrow \infty$ the QSZE reduces to the classical Szilard engine (CSZE), and the total work satisfies the relation $W_{\mathtt{tot}}=k_{B}T \mathtt{ln}2$ as obtained by Sang Wook Kim et al. [Phys. Rev. Lett. 106, 070401 (2011)] for one particle case.Comment: 17 pages, 3 figures, to be published in Annals of Physics(NY

Vascularization of Nanohydroxyapatite/Collagen/Poly(L-lactic acid) Composites by Implanting Intramuscularly In Vivo

It still remains a major challenge to repair large bone defects in the orthopaedic surgery. In previous studies, a nanohydroxyapatite/collagen/poly(L-lactic acid) (nHAC/PLA) composite, similar to natural bone in both composition and structure, has been prepared. It could repair small sized bone defects, but they were restricted to repair a large defect due to the lack of oxygen and nutrition supply for cell survival without vascularization. The aim of the present study was to investigate whether nHAC/PLA composites could be vascularized in vivo. Composites were implanted intramuscularly in the groins of rabbits for 2, 6, or 10 weeks (n=5×3). After removing, the macroscopic results showed that there were lots of rich blood supply tissues embracing the composites, and the volumes of tissue were increasing as time goes on. In microscopic views, blood vessels and vascular sprouts could be observed, and microvessel density (MVD) of the composites trended to increase over time. It suggested that nHAC/PLA composites could be well vascularized by implanting in vivo. In the future, it would be possible to generate vascular pedicle bone substitutes with nHAC/PLA composites for grafting