Pure annihilation decay of strange beauty meson into two charm heavy mesons

In this study, the heavy to heavy decay of \begin{document}$ B^0_s\rightarrow D^{*+}D^- $\end{document} is evaluated through the factorization approach by using the final state interaction as an effective correction. Under the factorization approach, this decay mode occurs only through the annihilation process, so a small amount is produced. Feynman's rules state that six meson pairs can be assumed for the intermediate states before the final meson pairs are produced. By taking into account the effects of twelve final state interaction diagrams in the calculations, a significant correction is obtained. These effects correct the value of the branching ratio obtained by the pure factorization approach from \begin{document}$ (2.41\pm1.37)\times10^{-5} $\end{document} to \begin{document}$ (8.27\pm2.23)\times10^{-5} $\end{document}. The value obtained for the branching ratio of the \begin{document}$ B^0_s\rightarrow D^{*+}D^- $\end{document} decay is consistent with the experimental results.     

Deciphering the Structure and Chemical Composition of Drug Nanocarriers: From Bulk Approaches to Individual Nanoparticle Characterization

Drug nanocarriers (NCs) with sizes usually below 200 nm are gaining increasing interest in the treatment of severe diseases such as cancer and infections. Characterization methods to investigate the morphology and physicochemical properties of multifunctional NCs are key in their optimization and in the study of their in vitro and in vivo fate. Whereas a variety of methods has been developed to characterize “bulk” NCs in suspension, the scope of this review is to describe the different approaches for the NC characterization on an individual basis, for which fewer techniques are available. The accent is put on methods devoid of labelling, which could lead to artefacts. For each characterization method, the principles and approaches to analyze the data are presented in an accessible manner. Aspects related to sample preparation to avoid artefacts are indicated, and emphasis is put on examples of applications. NC characterization on an individual basis allows gaining invaluable information in terms of quality control, on: i) NC localization and fate in biological samples; ii) NC morphology and crystallinity; iii) distribution of the NC components (drugs, shells), and iv) quantification of NCs’ chemical composition. The individual characterization approaches are expected to gain increasing interest in the near future.     

空化可压缩流动空穴溃灭激波特性研究

为深入研究空化可压缩流动中空泡/空泡团溃灭过程中激波产生、传播及其与空穴相互作用规律,本文采用数值模拟方法对空化可压缩流动空穴溃灭激波特性展开了研究.数值计算基于OpenFOAM开源程序,综合考虑蒸汽相和液相的压缩性,通过在原无相变两相可压缩求解器的控制方程中耦合模拟空化汽液相间质量交换的源项,实现了对空化流动的非定常可压缩计算.利用上述考虑汽/液相可压缩性的空化流动求解器,对周期性云状空化流动进行了数值模拟,并重点研究了空穴溃灭激波特性.结果表明:上述数值计算方法可以准确捕捉到空穴非定常演化过程及大尺度脱落空泡云团溃灭激波现象,大尺度脱落空泡云团溃灭过程分为3个阶段:(1) U型空泡团形成; (2) U型空泡团头部溃灭; (3) U型空泡团腿部溃灭.在U 型空泡团腿部溃灭瞬间,观察到激波产生,并向上游和下游传播,向上游传播的激波与空穴相互作用,导致水翼吸力面新生的附着型片状空穴回缩,直至完全溃灭.并且空穴溃灭激波存在回弹现象, 抑制了下一周期的空化发展.      

DNA interaction,cytotoxicity and molecular structure of cobalt complex of 4‐amino‐N‐(6‐chloropyridazin‐3‐yl)benzene sulfonamide in the presence of secondary ligand pyridine

Novel cobalt complex of 4‐amino‐N‐(6‐chloropyridazin‐3‐yl)benzene sulfonamide (sulfachloropyridazine) has been synthesized and characterized by elemental analysis, FT‐IR spectroscopy and magnetic susceptibility (VSM). Cobalt complex of Sulfachloropyridazine (Co‐SCP) crystallized in monoclinic space group P2₁/n with Z = 4. The structure is solved by direct method and refined to R = 0.099 for 4720 reflections with I ?4σ(I). The results of FT‐IR spectra suggest the binding of cobalt atom to the sulfonamide ligand which is in agreement with the crystal structure determination. In crystal structure, molecule is linked via, C‐H … π, C‐Cl … π and π … π intermolecular interactions. The computational studies like the optimization energy and root means square deviation compare with single crystal structure, frontier molecular orbital (Homo‐Lumo energy) and binding energy of the Co‐SCP has been carried out using DFT/B3LYP level of theory in gaseous phase. Hirshfeld surfaces and the 2D‐fingerprint analysis are performed to study the nature of interactions and their measurable contributions towards crystal packing. The interaction of the complex with DNA is investigated using viscosity measurement and absorption titration studies. The result shows the complex bind to DNA with intercalative mode with high DNA‐binding constant (K_b). Also, in vivo and in vitro cytotoxic studies are performed using S. pombe cells and brine shrimp lethality bioassay. DNA‐cleavage study shows better cleaving ability of the complex.     

Dinuclear cobalt and nickel complexes of a mercaptoacetic acid substituted 1,2,4‐triazole ligand: syntheses,structures and urease inhibitory studies

Because of its versatile coordination modes and strong coordination ability, the mercaptoacetic acid substituted 1,2,4‐triazole 2‐{[5‐(pyridin‐2‐yl)‐4H‐1,2,4‐triazol‐3‐yl]sulfanyl}acetic acid ( H₂L ) was synthesized and characterized. Treatment of H₂L with cobalt and nickel acetate afforded the dinuclear complexes {μ‐3‐[(carboxylatomethyl)sulfanyl]‐5‐(pyridin‐2‐yl)‐4H‐1,2,4‐triazol‐4‐ido‐κ²N¹,N⁵:N²,O}bis[aqua(methanol‐κO)cobalt(II)] methanol disolvate, [Co₂(C₉H₆N₄O₂S)₂(CH₃OH)₂(H₂O)₂]·2CH₃OH ( 1 ), and {μ‐3‐[(carboxylatomethyl)sulfanyl]‐5‐(pyridin‐2‐yl)‐4H‐1,2,4‐triazol‐4‐ido‐κ²N¹,N⁵:N²,O}bis[diaquanickel(II)] methanol disolvate dihydrate, [Ni₂(C₉H₆N₄O₂S)₂(H₂O)₄]·2CH₃OH·2H₂O ( 2 ), respectively. Complex 1 crystallized in the monoclinic space group P2₁/c, while 2 crystallized in the tetragonal space group I4₁/a. Single‐crystal X‐ray diffraction studies revealed that H₂L is doubly deprotonated and acts as a tetradentate bridging ligand in complexes 1 and 2 . For both of the obtained complexes, extensive hydrogen‐bond interactions contribute to the formation of their three‐dimensional supermolecular structures. Hirshfeld surface analysis was used to illustrate the intermolecular interactions. Additionally, the urease inhibitory activities of 1 , 2 and H₂L were investigated against jack bean urease, where the two complexes revealed strong urease inhibition activities.     

Voltammetric and Impedimetric Detection of Interaction Between Dacarbazine and Nucleic Acids

Dacarbazine (DTIC) is a chemotherapy drug that is used for the treatment of Hodgkin's lymphoma, malignant melanoma, childhood solid tumors and soft tissue sarcoma. The surface confined interaction between DTIC and nucleic acids was investigated for the first time in this study by using both differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) in combination with disposable pencil graphite electrodes. The oxidation signals of DTIC and guanine were measured before and after interaction process using DPV technique. The interaction of DTIC with nucleic acids; poly[A], poly[G], or double stranded of poly[A]‐poly[T] and poly[G]‐poly[C] was also examined using DPV. Furthermore, EIS technique was utilized for detection of the interaction between DTIC and nucleic acids; ssDNA/dsDNA, poly[A], poly[G], or double stranded poly[A]‐poly[T] and poly[G]‐poly[C].     

Synthesis and photophysical properties of dinaphtho[2,3-b:2′,3′-i]dihydrophenazine derivatives

A dinaphtho[2,3-b:2′,3′-i]dihydrophenazine (DNP) derivative was synthesized by Buchwald-Hartwig cross-coupling, and its electronic spectrum was compared with that of dinaphtho[b,i]dihydrophenazine-5,18-dione (DNP-dione) as an anthraquinone analog. An absorption band of DNP is attributed to extension of π-conjugation over the entire molecule via the N atom. DNP-dione showed a broad absorption band in the range 450–490?nm due to intramolecular charge-transfer interactions. Additionally, the absolute fluorescence quantum yield of DNP was larger than that of DNP-dione. DNP-dione exhibited reversible oxidation peaks and a similar oxidation potential to DNP, since there are very weak electronic interactions between the anthracene and anthraquinone units across the N atoms with the 4-octyloxyphenyl substituent.     

A New Planar Hexanuclear Dysprosium Cluster Exhibiting Slow Magnetic Relaxation Features

Reaction of the Schiff base ligand H₂L and dysprosium acetate result in a new planar Dy₆ cluster [Dy₆(μ₃‐OH)L₆(Ac)₆] · MeOH ( 1 ) [H₂L = N'‐(2‐hydroxybenzylidene)‐2‐(hydroxyimino)propanohydrazide, HAc = acetic acid], which was successfully structurally and magnetically characterized. Single‐crystal X‐ray diffraction analysis revealed that 1 contained a hexanuclear dysprosium cluster [Dy₆], which is composed of four Dy₃ triangular units. Magnetic measurements suggest that 1 displays single‐molecule magnet (SMM) behavior which is enhanced by applying a 4000 Oe direct‐current field. The effective anisotropic barrier U_eff/k_B = 14.9 K and the pre‐exponential factor τ₀ = 1.31 × 10^–6 s are also obtained. This work may provide more insights for the design and investigation of lanthanide‐based SMMs.     

Sequence‐Defined Introduction of Hydrophobic Motifs and Effects in Lectin Binding of Precision Glycomacromolecules

This study investigates the influence of an increasingly hydrophobic backbone of multivalent glycomimetics based on sequence‐defined oligo(amidoamines) on their resulting affinity toward bacterial lectins. Glycomacromolecules are obtained by stepwise assembly of tailor‐made building blocks on solid support, using both hydrophobic aliphatic and aromatic building blocks to enable a gradual change in hydrophobicity of the backbone. Their binding behavior toward model lectin Concanavalin A (ConA) is evaluated using isothermal titration calorimetry (ITC) and surface plasmon resonance (SPR) showing higher affinities for glycomacromolecules with higher content of hydrophobic and aromatic moieties in the backbone. Finally, glycomacromolecules are tested in a bacterial adhesion inhibition study against Escherichia coli where more hydrophobic backbones yield higher inhibitory potentials most likely due to additional secondary interactions with hydrophobic regions of the protein receptor as well as a change in conformation exposing carbohydrate ligands for increased binding. Overall, the results highlight the influence and thereby importance of the polymer backbone itself on the resulting properties of polymeric biomimetics.