A Hydrolytically Stable Vanadium(IV) Metal–Organic Framework with Photocatalytic Bacteriostatic Activity for Autonomous Indoor Humidity Control

Metal–organic frameworks (MOFs) with long-term stability and reversible high water uptake properties can be ideal candidates for water harvesting and indoor humidity control. Now, a mesoporous and highly stable MOF, BIT-66 is presented that has indoor humidity control capability and a photocatalytic bacteriostatic effect. BIT-66 (V₃(O)₃(H₂O)(BTB)₂), possesses prominent moisture tunability in the range of 45–60 % RH and a water uptake and working capacity of 71 and 55 wt %, respectively, showing good recyclability and excellent performance in water adsorption–desorption cycles. Importantly, this MOF demonstrates a unique photocatalytic bacteriostatic behavior under visible light, which can effectively ameliorate the bacteria and/or mold breeding problem in water adsorbing materials.     

新型丁烯内酯衍生物的设计合成及诱导胃癌细胞凋亡研究

开发了一条合成天然产物Uncinine的新方法,基于此设计合成了一系列新型的丁烯内酯衍生物.通过噻唑蓝(MTT)法评价了目标化合物对胃癌细胞的增殖抑制活性,分析了其构效关系.其中,3-吗啉甲基-4-(4-叔丁基苯基)亚基丁烯内酯(9l)对MGC803的IC50为2.9μmol/L,对胃癌细胞MGC803、HGC27以及SGC7901具有明显的选择性增殖抑制作用,而对正常的胃粘膜上皮细胞GES1具有较小的毒性.初步的作用机制研究表明,化合物9l诱导胃癌细胞MGC803凋亡依赖Caspase 9/3激活.     

Remote regioselective organocatalytic asymmetric [3+2] cycloaddition of N-2,2,2-trifluoroethyl isatin ketimines with cyclic 2,4-dienones

An organocatalytic asymmetric [3+2] cycloaddition of trifluoromethyl-containing azomethine ylides with cyclic 2,4-dienones was developed.The process enables efficient incorporation of CF3 groups into functionalized spiro [pyrro lid in-3,2'-oxindoles] in high yields with good to excellent enantio-and diastereoselectivities.     

Comparison of Two Rhodamine-Polyamine Polystyrene Solid-phase Fluorescence Sensors for Hg(II) Detection Based on Theoretical Calculation

Two novel rhodamine-based polystyrene solid-phase fluorescence sensors PS-PA-I and PS-PA-II with different lengths of polyamines were synthesized for Hg(II) determination. The detection mechanism involving the Hg(II) chelation-induced spirocycle open of rhodamine was proposed with the aid of theoretical calculation. The stronger N-Hg bond and the longer polyamine chain in PS-PA-II led to a better selectivity, much higher and more quickly fluorescence response to Hg(II).     

Sequence‐Dependent DNA Functionalization of Upconversion Nanoparticles and Their Programmable Assemblies

DNA‐modified lanthanide‐doped upconversion nanoparticles (DNA‐UCNPs) that combine the functions of DNA and the optical features of UCNPs have shown great promise in a wide range of fields. However, challenges remain in precisely tethering and orienting the DNA strands on the UCNP surface. Herein, we systematically investigate the sequence dependence of DNAs in their interactions with UCNPs, and reveal that poly‐cytosine (poly‐C) has high affinity for the UCNP surface. A general approach to synthesize monodispersed DNA‐UCNP conjugates is developed using poly‐C‐containing diblock DNA strands. The poly‐C segment of the DNA strand binds to the surfaces of UCNPs and the second segment is oriented perpendicularly on the UCNP surface, making the DNA‐UCNPs highly stable and monodispersed in aqueous solution. The dense layer of DNA on the UCNP surface enables the programmable assembly of UCNPs with other DNA‐functionalized nanoparticles or DNA origamis through hybridization, resulting in the formation of well‐organized complex structures.     

3‐O‐Sulfation of Heparan Sulfate Enhances Tau Interaction and Cellular Uptake

Prion‐like transcellular spreading of tau in Alzheimer's Disease (AD) is mediated by tau binding to cell surface heparan sulfate (HS). However, the structural determinants for tau–HS interaction are not well understood. Microarray and SPR assays of structurally defined HS oligosaccharides show that a rare 3‐O‐sulfation (3‐O‐S) of HS significantly enhances tau binding. In Hs3st1^?/? (HS 3‐O‐sulfotransferase‐1 knockout) cells, reduced 3‐O‐S levels of HS diminished both cell surface binding and internalization of tau. In a cell culture, the addition of a 3‐O‐S HS 12‐mer reduced both tau cell surface binding and cellular uptake. NMR titrations mapped 3‐O‐S binding sites to the microtubule binding repeat 2 (R2) and proline‐rich region 2 (PRR2) of tau. Tau is only the seventh protein currently known to recognize HS 3‐O‐sulfation. Our work demonstrates that this rare 3‐O‐sulfation enhances tau–HS binding and likely the transcellular spread of tau, providing a novel target for disease‐modifying treatment of AD and other tauopathies.     

Supramolecular self‐assembly modification of ammonium polyphosphate and its flame retardant application in polypropylene

In order to improve its water resistance and compatibility with polymer matrix, ammonium polyphosphate (APP) is modified with melamine‐trimesic acid (MEL‐TA) aggregates by supramolecular self‐assembly technology. Chemical structure and morphology of APP@MEL‐TA are investigated by Fourier transform infrared spectroscopy and scanning electron microscopy (SEM), respectively. Intumescent flame retardant system of APP@MEL‐TA and charring‐foaming agent is introduced into polypropylene (PP) matrix. The flammability and combustion behavior of PP composites are investigated by limiting oxygen index (LOI), UL‐94 vertical burning, and cone calorimetry tests. In terms of LOI values and cone combustion results, APP@MEL‐TA performs better than pristine APP. Char residue of PP composites is investigated by SEM and Raman spectra. Flame retardant mechanisms are proposed based on thermal decomposition, combustion results, and analysis on char residue.     

A Hydrolytically Stable Vanadium(IV) Metal–Organic Framework with Photocatalytic Bacteriostatic Activity for Autonomous Indoor Humidity Control

Metal–organic frameworks (MOFs) with long‐term stability and reversible high water uptake properties can be ideal candidates for water harvesting and indoor humidity control. Now, a mesoporous and highly stable MOF, BIT‐66 is presented that has indoor humidity control capability and a photocatalytic bacteriostatic effect. BIT‐66 (V₃(O)₃(H₂O)(BTB)₂), possesses prominent moisture tunability in the range of 45–60 % RH and a water uptake and working capacity of 71 and 55 wt %, respectively, showing good recyclability and excellent performance in water adsorption–desorption cycles. Importantly, this MOF demonstrates a unique photocatalytic bacteriostatic behavior under visible light, which can effectively ameliorate the bacteria and/or mold breeding problem in water adsorbing materials.     

A Phototheranostic Strategy to Continuously Deliver Singlet Oxygen in the Dark and Hypoxic Tumor Microenvironment

Continuous irradiation during photodynamic therapy (PDT) inevitably induces tumor hypoxia, thereby weakening the PDT effect. In PDT‐induced hypoxia, providing singlet oxygen from stored chemical energy may enhance the cell‐killing effect and boost the therapeutic effect. Herein, we present a phototheranostic (DPPTPE@PEG‐Py NPs) prepared by using a 2‐pyridone‐based diblock polymer (PEG‐Py) to encapsulate a semiconducting, heavy‐atom‐free pyrrolopyrrolidone‐tetraphenylethylene (DPPTPE) with high singlet‐oxygen‐generation ability both in dichloromethane and water. The PEG‐Py can trap the ¹O₂ generated from DPPTPE under laser irradiation and form a stable intermediate of endoperoxide, which can then release ¹O₂ in the dark, hypoxic tumor microenvironment. Furthermore, fluorescence‐imaging‐guided phototherapy demonstrates that this phototheranostic could completely inhibit tumor growth with the help of laser irradiation.     

Cell membrane chromatography coupled online with LC‐MS to screen anti‐anaphylactoid components from Magnolia biondii Pamp. targeting on Mas‐related G protein‐coupled receptor X2

Mas‐related G protein‐coupled receptor X2 was a mast cell–specific receptor mediating anaphylactoid reactions by activating mast cells degranulation, and it was also identified as a target for modulating mast cell–mediated anaphylactoid and inflammatory diseases. The anti‐anaphylactoid drugs used clinically disturb the partial effect of partial mediators released by mast cells. The small molecule of Mas‐related G protein‐coupled receptor X2 specific antagonists may provide therapeutic action for the anaphylactoid and inflammatory diseases in the early stage. In this study, the Mas‐related G protein‐coupled receptor X2 high expression cell membrane chromatography was coupled online with liquid chromatography and mass spectrometry and successfully used to screen anti‐anaphylactoid components from Magnolia biondii Pamp. Fargesin and pinoresinol dimethyl ether were identified as potential anti‐anaphylactoid components. Bioactivity of these two components were investigated by β hexosaminidase and histamine release assays on mast cells, and it was found that these two components could inhibit β hexosaminidase and histamine release in a concentration‐dependent manner. This Mas‐related G protein‐coupled receptor X2 high expression cell membrane chromatography coupled online with liquid chromatography and mass spectrometry system could be applied for screening potential anti‐anaphylactoid components from natural medicinal herbs. This study also provided a powerful system for drug discovery in natural medicinal herbs.