Derivatives of 4‐(2‐hydro­xy­lphenyl)‐2‐phenyl‐2,3‐di­hydro‐1,5‐benzothiazepine

In the structures of 2‐(4‐chloro­phenyl)‐4‐(2‐hydroxyphenyl)‐2,3‐di­hydro‐1,5‐benzo­thia­zepine, C₂₁H₁₆ClNOS, 4‐(2‐hy­droxy­phenyl)‐2‐(4‐tolyl)‐2,3‐di­hydro‐1,5‐ben­zo­thia­zepine, C₂₂H₁₉NOS, and 4‐(2‐hydroxyphenyl)‐2‐(3‐methoxy­phenyl)‐2,3‐di­hydro‐1,5‐benzo­thia­zepine, C₂₂H₁₉NO₂S, the central seven‐membered heterocyclic rings adopt twist‐boat conformations in which the N atoms are involved in strong intramolecular hydrogen bonds with the hydroxyl H atoms, resulting in six‐membered rings.     

碳点的高性能化和功能化改性:方法、特性与展望

碳点作为一种新型碳纳米材料,由于其出色的光学性能、低毒性、良好的生物相容性和易修饰性而被广泛应用于各个领域。为了满足不同领域的需求,几种用以调控碳点光学性能的方法已被提出,例如杂原子掺杂、半导体量子点掺杂、聚合物钝化和改性以及主-客体构建。其中,杂原子掺杂是通过单原子或多原子引入电子给体或受体改变其相邻碳原子的电子密度来增加荧光强度;半导体量子点也可与碳点进行复合提升电子分离效率而起到荧光增强的效果;就聚合物改性而言,聚合物不仅可以对碳点表面实施钝化和功能化,而且其固态(或固化)薄膜可以提供紧密的空间促进碳点表面的辐射跃迁起到荧光增强的效果。此外,由碳点-染料和多孔材料-碳点构成的两种主要的主-客体结构中,前者不仅对碳点的荧光发射强度有着促进的作用,更使得碳点具备了显著的红/近红外荧光发射性能,后者对固态发光碳点不仅提供了可能性和设计的灵活性,且为打开碳点新的应用领域提供了机会。本文将围绕四种碳点功能化的方法逐步展开讨论,并介绍相应碳点的光学性能、发光机理和潜在应用;论述功能化碳点的研究现状,并展望功能化碳点的研究方向。     

Selection of possible marker peptides for the detection of major ruminant milk proteins in food by liquid chromatography-tandem mass spectrometry

The aim of this work was the determination of peptides, which can function as markers for identification of milk allergens in food samples. Emphasis was placed on two casein proteins (α- and β-casein) and two whey proteins (α-lactalbumin and β-lactoglobulin). In silico tryptic digestion provided preliminary information about the expected peptides. After tryptic digestion of four milk allergens, the analytical data obtained by combination of reversed-phase high performance liquid chromatography and quadrupole tandem mass spectrometry (LC-MS/MS) led to the identification of 26 peptides. Seven of these peptides were synthesized and used for calibration of the LC-MS/MS system. Species specificity of the selected peptides was sought by BLAST search. Among the selected peptides, only LIVTQTMK from β-lactoglobulin (m/z 467.6, charge 2+) was found to be cow milk specific and could function as a marker. Two other peptides, FFVAPFPEVFGK from α-casein (m/z 693.3, charge 2+) and GPFPIIV from β-casein (m/z 742.5, charge 1+), occur in water buffalo milk too. The other four peptides appear in the milk of other species also and can be used as markers for ruminant species milk. Using these seven peptides, a multianalyte MS-based method was developed. For the establishment of the method, it was applied at first to different dairy samples, and then to chocolate and blank samples, and the peptides could be determined down to 1 ng/mL in food samples. At the end, spiked samples were measured, where the target peptides could be detected with a high recovery (over 50%).     

GC–MS Analysis and In Vivo and Ex Vivo Antidiarrheal and Antispasmodic Effects of the Methanolic Extract of Acacia nilotica

This present study evaluated and rationalized the medicinal use of the fruit part of Acacia nilotica methanolic extract. The phytochemicals were detected using gas chromatography–mass spectrometry (GC–MS) while the in vivo antidiarrheal test was done using Swiss albino mice. To determine the details of the mechanism(s) involved in the antispasmodic effect, isolated rat ileum was chosen using different ex vivo assays by maintaining a physiological environment. GC–MS results showed that A. nilotica contained pyrogallol as the major polyphenol present (64.04%) in addition to polysaccharides, polyphenol, amino acid, steroids, fatty acid esters, and triterpenoids. In the antidiarrheal experiment, A. nilotica inhibited diarrheal episodes in mice significantly (p < 0.05) by 40% protection of mice at 200 mg/kg, while 80% protection was observed at 400 mg/kg by the orally administered extract. The highest antidiarrheal effect was observed with loperamide (p < 0.01), used as a control drug. In the ex vivo experiments, A. nilotica inhibited completely in increasing concentrations (0.3 to 10 mg/mL) the carbachol (CCh; 1 µM) and high K⁺ (80 mM)-evoked spasms in ileum tissues at equal potencies (p > 0.05), similar to papaverine, a dual inhibitor of the phosphodiesterase enzyme (PDE) and Ca⁺⁺ channels. The dual inhibitory-like effects of A. nilotica on PDE and Ca⁺⁺ were further validated when A. nilotica extract (1 and 3 mg/mL)-pre-incubated ileum tissues potentiated and shifted isoprenaline relaxation curves towards lower doses (leftward), similar to papaverine, thus confirming the PDE inhibitory-like mechanism whereas its CCB-like effect of the extract was confirmed at 3 and 5 mg/mL by non-specific inhibition of CaCl₂-mediated concentration response curves towards the right with suppression of the maximum peaks, similar to verapamil, used as standard CCB. Thus, this study characterized the chemical composition and provides mechanistic support for medicinal use of A. nilotica in diarrheal and hyperactive gut motility disorders.     

Molecular Simulations and Drug Discovery of Adenosine Receptors

G protein-coupled receptors (GPCRs) represent the largest family of human membrane proteins. Four subtypes of adenosine receptors (ARs), the A₁AR, A_2AAR, A_2BAR and A₃AR, each with a unique pharmacological profile and distribution within the tissues in the human body, mediate many physiological functions and serve as critical drug targets for treating numerous human diseases including cancer, neuropathic pain, cardiac ischemia, stroke and diabetes. The A₁AR and A₃AR preferentially couple to the G_i/o proteins, while the A_2AAR and A_2BAR prefer coupling to the G_s proteins. Adenosine receptors were the first subclass of GPCRs that had experimental structures determined in complex with distinct G proteins. Here, we will review recent studies in molecular simulations and computer-aided drug discovery of the adenosine receptors and also highlight their future research opportunities.     

Shape evolution in <Superscript>76,78</Superscript>Kr nuclei at high spins in tilted axis cranking Hartree-Fock-Bogoliubov approach

A two-dimensional tilted axis cranking Hartree-Fock-Bogoliubov (CHFB) calculation is performed for ⁷⁶Kr and ⁷⁸Kr nuclei up to high spins J = 30 employing a pairing-plus-quadrupole (PPQ) model interaction Hamiltonian. Intricate details of the evolution of single particle structures and shapes as a function of spin have been investigated. The results show the existence of energy levels with high K quantum numbers lying close to the yrast line in both the nuclei. Such high K states should exhibit isomeric characteristics due to the K-selection rules for the γ-decays. Moreover, in ⁷⁸Kr a new band with J = 20–30 lying below the observed ground band is predicted.      

Optical properties of pyridine funtionalized TbF<Subscript>3</Subscript> nanoparticles

The preparation of pyridine functionalized TbF₃ nanoparticles are described in this report. Synthesized nanoparticles were characterized using the TEM, UV/Vis, FTIR and photoluminescence spectroscopy. TEM micrograph reveals the nanorod shaped, uniform in size with a particles size in the range of 20–30 nm. FTIR spectrum shown characteristic absorption bands of pyridine and a small intensity band at 411 cm⁻¹ corresponding metal nitrogen ν(Tb–N) bonding. Uv-vis spectrum shown the characteristic absorption transitions of Tb³⁺ ion. A strong emission transition at 540 nm (⁵D₄ → ⁷F₅) was observed on excite by visible light at 414 nm.     

Convergence to the equilibrium for the Pauli equation without detailed balance condition

Let $A?B$ be an extension of commutative rings with identity, X an analytic indeterminate over B, and $R\text{:}=A+XB[[X]]$, the subring of the formal power series ring $B[[X]]$, consisting of the series with constant terms in A. In this Note we study when the ring R is Noetherian. We prove that R is Noetherian if and only if A is Noetherian and B is a finitely generated A-module. To cite this article: S. Hizem, A. Benhissi, C. R. Acad. Sci. Paris, Ser. I 340 (2005).