Structural characterizations of protonated homodimers of amino acids: Revealed by infrared multiple photon dissociation (IRMPD) spectroscopy and theoretical calculations

Photon affinity can serve as a probe for predicting the structures of protonated homodimers of amino acids.     

Effects of the Pulse Polarity on Helium Plasma Jets: Discharge Characteristics,Key Reactive Species,and Inactivation of Myeloma Cell

In this paper, we report the effects of the pulse polarity on the plasma jet’s discharge characteristics, particularly, on the production of the reactive oxygen and nitrogen species (RONS) and the inactivation efficiency of myeloma cells, for the purpose of identifying and elucidating the correlation between the dose of RONS and cell viability. Experimental results reveal that the positive plasma jet has a longer length than that for negative plasma jet with the equivalent pulse power. The positive pulse plasma jet would produce higher production of the excited reactive species (OH(A), N₂(C), N₂⁺(B), He(3s³S), O(3p⁵P)), the positive ions (N⁺, O⁺, N₂⁺, O₂⁺), and the aqueous species O₂^?, OH, and ONOO^?, while negative plasma jet would generate higher concentration of the negative ions (OH^?, O₂^?, NO₂^?, NO₂^?) and the aqueous species NO₂^? and NO₃^?. Additionally, the myeloma cells treated by positive plasma jet results in more cell apoptosis and more CD95 expression compared to negative plasma jet, indicating the impact for the cell apoptosis is more significant in the cellular response to the positive plasma jet. By comparing and analyzing the different doses of RONS to the responses of myeloma cells under positive and negative pulse plasma jet, our findings suggest the cell viability has a positive correlation with the concentration of the concentration of ONOO^? and the concentration ratio of H₂O₂ to NO₂^?, implying the high concentrations for ONOO^? and H₂O₂ might be responsible for the inactivation of myeloma cancer cells.     

Concise total synthesis of AB5046A and AB5046B

Two naturally occurring rare 5-oxo β-triketones, AB5046A and AB5046B, were efficiently synthesized in five linear steps with overall yields of 36% and 28%, respectively. The synthetic strategy highlighted the readily preparation of the key intermediate, 3-ethoxy-5-hydroxycyclohex-2-enone, from commercially available phloroglucinol.     

5-二乙胺基-2-(吡啶-2’-亚氨甲基)苯酚的合成及其对Zn2+的识别

本文利用2-氨基吡啶与4-二乙胺基水杨醛反应合成了5-二乙胺基-2-(吡啶-2’-亚氨甲基)苯酚(探针L),对其结构进行了表征。在DMSO/Tris(6:4, v/v, pH =7.4)溶液中,探针L高选择性荧光“关-开”识别Zn₂₊,在365 nm紫外灯照射下,由无荧光变成蓝色荧光。实验表明,探针L与Zn₂₊的结合比为1:1,结合常数为2.6×10₃ L. mol_-1,检测限为 9.39×10_-7mol/L,pH适用范围为7-11,并可检测水样中的Zn₂₊。     

润湿性表面强化冷凝传热的研究进展

固体表面的润湿特性对冷凝传热具有重要的影响。本文分析了冷凝传热的机理,介绍了现阶段对不同冷凝方式的判定方法,总结了不同润湿性表面的制备方法,概述了蒸汽在亲水表面、疏水表面和组合表面上的冷凝传热性能,总结了该领域目前存在的问题。本文为利用表面润湿性强化传热提供了较为系统的综述,为强化冷凝传热提供思路。     

Lymphatic targeting of hematoporphyrin monomethyl ether using poly (butyl-cyanoacrylate) based nanoparticle drug delivery system

The traditional treatment has inevitable drawbacks of nonspecific lymph targeting, poor therapeutic efficiency and residual metastatic for advanced cancer patients with lymph node metastases. To overcome these shortcomings, we prepare a nano-carrier drug delivery system. Photosensitizer hematoporphyrin monomethyl ether (HMME)-loaded poly (n-butylcyanoacrylate) nanoparticles (PBCA-NPs) was prepared successfully. The particle size was approximately 160 nm, the envelopment rate was 87.9%, and the drug loading rate was about 13.4%. The drug release study in vitro showed that the cumulative release rates of HMME-PBCA-NPs group was much less than free HMME group. The drug distribution in different tissues showed that the peak-reach time was 3 h in free HMME group and 6 h in nanoparticles group. All of these results confirmed the slow release characteristic of nanoparticles. In lymph node tissues, the HMME concentrations in HMME-PBCA-NPs group were much higher than those of the free HMME group at any time points we tested, in which the maximum difference concentration of HMME appeared at 6 h (1.2884?±?0.04695 vs. 0.0438?±?0.00558 µg/mg) after drug delivery. The mesenteric lymph nodes of rabbits were enlarged obviously in the NP group than in free HMME group at 6 h after drug delivery. All of these results confirmed the slow release characteristic and the lymphatic targeting characteristic of nanoparticles. In summary, we developed a lymphatic targeting nanoparticles drug delivery system successfully, which showed perfect lymph targeting and has the potential to be a new therapy strategy for advanced cancer patients with lymph node metastasis.     

An Unconventional Polymerization Route to Hydrophilic Fluorescent Organic Nanoparticles for Multicolor Cellular Bioimaging

We demonstrated an unconventional polymerization route to synthesize hydrophilic fluorescent organic nanoparticles (FONs) for multicolor cellular bioimaging in this contribution. The route benefits from our unexpected discovery of a rapid polymerization reaction between 1,6‐hexanediol dipropiolate and 2,4,6‐triazide‐1,3,5‐triazine under the catalysis of N,N,N′,N′′,N′′‐pentamethyldiethylenetriamine (PMDETA). Interestingly, the 2,4,6‐triazide‐1,3,5‐triazine and PMDETA system can also induce rapid free radical polymerization at room temperature. The as‐prepared FONs exhibited promising water solubility and stability with an average diameter of 20 nm. The excitation wavelength‐dependent fluorescent properties endow the FONs with blue, yellow, and red fluorescent emission under UV, blue, and green excitation, respectively. The cytotoxicity of FONs was investigated by using a Cell Counting Kit (CCK‐8) assay, which indicated good biocompatiblity. More importantly, the cell uptake experiment verified the FONs were excellent fluorescent nanoprobes for multicolor cellular bioimaging. Therefore, this unconventional route provides a novel fabrication strategy of highly hydrophilic FONs for biomedical applications.     

Alloying n‐Butylamine into CsPbBr3 To Give a Two‐Dimensional Bilayered Perovskite Ferroelectric Material

Cesium‐lead halide perovskites (e.g. CsPbBr₃) have gained attention because of their rich physical properties, but their bulk ferroelectricity remains unexplored. Herein, by alloying flexible organic cations into the cubic CsPbBr₃, we design the first cesium‐based two‐dimensional (2D) perovskite ferroelectric material with both inorganic alkali metal and organic cations, (C₄H₉NH₃)₂CsPb₂Br₇ ( 1 ). Strikingly, 1 shows a high Curie temperature (T_c=412 K) above that of BaTiO₃ (ca. 393 K) and notable spontaneous polarization (ca. 4.2 μC cm^?2), triggered by not only the ordering of organic cations but also atomic displacement of inorganic Cs⁺ ions. To our knowledge, such a 2D bilayered Cs⁺‐based metal–halide perovskite ferroelectric material with inorganic and organic cations is unprecedented. 1 also shows photoelectric semiconducting behavior with large “on/off” ratios of photoconductivity (>10³).     

Antimony‐Functionalized Phosphine‐Based Photopolymer Networks

The synthesis of phosphane‐ene photopolymer networks, where the networks are composed of crosslinked tertiary alkyl phosphines are reported. Taking advantage of the rich coordination chemistry of alkyl phosphines, stibino‐phosphonium and stibino‐bis(phosphonium) functionalized polymer networks could be generated. Small‐molecule stibino‐phosphonium and stibino‐bis(phosphonium) compounds have been well characterized previously and were used as models for spectroscopic comparison to the macromolecular analogues by NMR and XANES spectroscopy. This work reveals that the physical and electronic properties of the materials can be tuned depending on the type of coordination environment. These materials can be used as ceramic precursors, where the Sb‐functionalized polymers influence the composition of the resulting ceramic.     

Efficient difluoromethylation of isoflavonoids and flavonoid under mild conditions

A simple and efficient protocol for difluoromethylation of isoflavones, flavonoids, and coumarins has been developed. The protocol uses readily available, non-ozone-depleting and easy handling BrCF₂PO(OEt)₂ as difluorocarbene precursor. The reaction underwent the formation of difluorocarbene under mild reaction conditions with relatively weak base therefore demonstrates high selectivity. Application of the reaction led to difluoromethylated biologically relevant molecules.