Short-Range Structure of Amorphous Calcium Hydrogen Phosphate

Copyright © 2019 American Chemical Society. Calcium orthophosphates (CaPs) are the hard constituents of bones and teeth, and thus of ultimate importance to humankind, while amorphous CaPs (ACPs) may play crucial roles in CaP biomineralization. Among the various ACPs with Ca/P atomic ratios between 1.0-1.5, an established structural model exists for basic ACP (Ca/P = 1.5), while those of other ACPs remain unclear. Herein, the structure of amorphous calcium hydrogen phosphate (ACHP; Ca/P = 1.0) obtained via aqueous routes at near-neutral pH values, without stabilizers, was studied by experiments (mainly, TEM with ED, XRD, IR, and NMR spectroscopies, as well as XAS) and computer simulation. Our results globally show that ACHP has a distinct short-range structure, and we propose calcium hydrogen phosphate clusters (CHPCs) as its basic unit. This model is consistent with both computer simulations and the experimental results, where CHPCs are arranged together with water molecules to build up ACHP. We demonstrate that Posner's clusters, which are conventionally accepted to be the building unit of basic ACPs, do not represent the short-range structure of ACHP, as Posner's clusters and CHPCs are structurally distinct. This finding is important not only for the determination of the structures of diverse ACPs with varying Ca/P atomic ratios but also for fundamental understanding of a major mineral class that is central to biomineralization in vertebrates and, thus, humans, in particular.

Comparison of Structural Development and Biochemical Accumulation of Waxy and Non-waxy Wheat Caryopses

This study was conducted to compare structural development and biochemical accumulation of waxy and non-waxy wheat (NW) caryopses. The caryopses’ microstructure of the waxy wheat (WW) and NW cultivars at different developmental stages were observed under light, fluorescence, and scanning electron microscope. The results were as follows: Compared with NW,WWhad a shorter maturation duration, which was reflected in several following characteristics. Programmed cell death of the pericarp began earlier, and the chlorophyll-containing layer in the pericarp was smaller. Vacuoles in chalazal cells accumulated more tannins at different developmental stages. Starch granules and protein bodies in the endosperm showed a higher accumulation level in developing caryopses, and aleurone cells were larger in size with larger numbers of aleurone grains. An analysis of the element content indicated that the mineral elements Mg, P, K, and Ca exhibited a higher content, while the heavy elements Cr, Cd, and Pb exhibited a lower content in the aleurone layer

Revisión sobre métodos de preparación, mecanismos y aplicaciones de péptidos antioxidantes en aceites

Natural antioxidants, especially those used in edible oil, are safer compared to chemically synthesized antioxidants. Therefore, research on natural antioxidants has become prevelant. Antioxidant peptides derived from food protein can effectively prevent oil oxidation. Protein hydrolyzation is widely applied for the production of antioxidant peptides in industry, and bioinformatics is employed nowadays to generate the desired peptide sequence. Furthermore, the mechanism of antioxidant peptides in the oil system is still controversial, which limits the further development of antioxidant peptides as food antioxidants. This review introduces the preparation method of antioxidant peptides and their mechanisms as well as applications in the oil. It will help to comprehensively understand the function of antioxidant peptides and promote their development in the oil field.Los antioxidantes naturales, especialmente utilizados en aceites comestibles, son más seguros en comparación con los antioxidantes sintetizados químicamente. Por lo tanto, la investigación sobre antioxidantes naturales se convierte en un punto de interés. Los péptidos antioxidantes derivados de las proteínas alimentarias pueden prevenir eficazmente la oxidación del aceite. La hidrolización de proteínas se usa ampliamente en la industria para la producción de péptidos antioxidantes y la bioinformática se emplea hoy en día para generar la secuencia de péptidos deseada. Además, el mecanismo de los péptidos antioxidantes en el sistema oleoso sigue siendo controvertido, lo que limita el desarrollo posterior de péptidos antioxidantes como antioxidantes alimentarios. Esta revisión presenta el método de preparación de péptidos antioxidantes y su mecanismo, así como las aplicaciones en aceite, lo que ayudará a comprender de manera integral la función de los péptidos antioxidantes y promoverá su desarrollo en el campo petrolero

Analysis of the vector meson transitions among the heavy quarkonium states

In this article, we study the vector meson transitions among the charmonium and bottomonium states with the heavy quark effective theory in an systematic way, and make predictions for the ratios among the vector meson decay widths of a special multiplet to another multiplet. The predictions can be confronted with the experimental data in the future.Comment: 14 pages, published versio

Direct Measurements of the Branching Fractions for D0→K−e+νeD^0 \to K^-e^+\nu_e and D0→π−e+νeD^0 \to \pi^-e^+\nu_e and Determinations of the Form Factors f+K(0)f_{+}^{K}(0) and f+π(0)f^{\pi}_{+}(0)

The absolute branching fractions for the decays $D^0 \to K^-e ^+\nu_e$ and $D^0 \to \pi^-e^+\nu_e$ are determined using $7584\pm 198 \pm 341$ singly tagged $\bar D^0$ sample from the data collected around 3.773 GeV with the BES-II detector at the BEPC. In the system recoiling against the singly tagged $\bar D^0$ meson, $104.0\pm 10.9$ events for $D^0 \to K^-e ^+\nu_e$ and $9.0 \pm 3.6$ events for $D^0 \to \pi^-e^+\nu_e$ decays are observed. Those yield the absolute branching fractions to be $BF(D^0 \to K^-e^+\nu_e)=(3.82 \pm 0.40\pm 0.27)$ and $BF(D^0 \to \pi^-e^+\nu_e)=(0.33 \pm 0.13\pm 0.03)$. The vector form factors are determined to be $|f^K_+(0)| = 0.78 \pm 0.04 \pm 0.03$ and $|f^{\pi}_+(0)| = 0.73 \pm 0.14 \pm 0.06$. The ratio of the two form factors is measured to be $|f^{\pi}_+(0)/f^K_+(0)|= 0.93 \pm 0.19 \pm 0.07$.Comment: 6 pages, 5 figure

Search for the Lepton Flavor Violation Processes J/ψ→J/\psi \to μτ\mu\tau and eτe\tau

The lepton flavor violation processes $J/\psi \to \mu\tau$ and $e\tau$ are searched for using a sample of 5.8$\times 10^7$ $J/\psi$ events collected with the BESII detector. Zero and one candidate events, consistent with the estimated background, are observed in $J/\psi \to \mu\tau, \tau\to e\bar\nu_e\nu_{\tau}$ and $J/\psi\to e\tau, \tau\to\mu\bar\nu_{\mu}\nu_{\tau}$ decays, respectively. Upper limits on the branching ratios are determined to be $Br(J/\psi\to\mu\tau)<2.0 \times 10^{-6}$ and $Br(J/\psi \to e\tau) < 8.3 \times10^{-6}$ at the 90% confidence level (C.L.).Comment: 9 pages, 2 figure

Partial Wave Analysis of J/ψ→γ(K+K−π+π−)J/\psi \to \gamma (K^+K^-\pi^+\pi^-)

BES data on $J/\psi \to \gamma (K^+K^-\pi^+\pi^-)$ are presented. The $K^*\bar K^*$ contribution peaks strongly near threshold. It is fitted with a broad $0^{-+}$ resonance with mass $M = 1800 \pm 100$ MeV, width $\Gamma = 500 \pm 200$ MeV. A broad $2^{++}$ resonance peaking at 2020 MeV is also required with width $\sim 500$ MeV. There is further evidence for a $2^{-+}$ component peaking at 2.55 GeV. The non-$K^*\bar K^*$ contribution is close to phase space; it peaks at 2.6 GeV and is very different from $K^{*}\bar{K^{*}}$.Comment: 15 pages, 6 figures, 1 table, Submitted to PL

The σ\sigma pole in J/ψ→ωπ+π−J/\psi \to \omega \pi^+ \pi^-

Using a sample of 58 million $J/\psi$ events recorded in the BESII detector, the decay $J/\psi \to \omega \pi^+ \pi^-$ is studied. There are conspicuous $\omega f_2(1270)$ and $b_1(1235)\pi$ signals. At low $\pi \pi$ mass, a large broad peak due to the $\sigma$ is observed, and its pole position is determined to be $(541 \pm 39)$ - $i$ $(252 \pm 42)$ MeV from the mean of six analyses. The errors are dominated by the systematic errors.Comment: 15 pages, 6 figures, submitted to PL

Measurements of J/psi Decays into 2(pi+pi-)eta and 3(pi+pi-)eta

Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector, the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and (7.24+-0.96+-1.11)X10^{-4}, respectively.Comment: 11 pages, 6 figure