An amphiphilic molecule with a single fluorophore exhibits multiple stimuli-responsive behavior

Fluorescent materials that respond to multiple stimuli have broad applications ranging from sensing and bioimaging to information encryption. Herein, we report the design and synthesis of a single-fluorophore-based amphiphile DCSO, which shows temperature-, solvent-, humidity-, and radiation-dependent fluorescence. DCSO consists of a dicyanostilbene (DCS) group as a rigid hydrophobic core with oligo(ethylene glycol) (OEG) chains at both ends as a flexible hydrophilic periphery. The DCS group acts as a highly efficient fluorophore, while the OEG chain endows the molecule with thermo-responsiveness. Fluorescent colors can vary from blue to green to yellow in response to external stimuli. On the basis of light radiation, we demonstrate that this system can be applied to time-dependent information encryption, in which the correct information can only be read at a specific time under irradiation. This work further demonstrates the usefulness and application of single-fluorophore-based luminescent materials with multiple stimuli-responsive functions.     

新型氮杂环卡宾催化剂的合成及其在烯烃的自由基氟烷基酰化反应中的应用研究

以环庚酮及环己（庚）胺为起始原料,经溴代、环化、脱硫等反应,以良好的收率合成了环烷基取代的新型噻唑骨架的氮杂环卡宾催化剂。结果表明,在该催化剂催化下成功地实现了烯烃的自由基氟烷基酰化反应,以中等的收率完成了三种类型的γ-氟烷基取代酮的高效合成。所得化合物通过¹H NMR, ¹³C NMR, ¹⁹F NMR和HR-MS（ESI-TOF）进行表征。     

L-Arginine/nanofish bone nanocomplex enhances bone regeneration via antioxidant activities and osteoimmunomodulatory properties

In this study,a promising strategy has been developed to promote bone regeneration by combining antioxidant activities and osteoimmunomodulatory properties.Herein,an L-arginine/nanofish bone(Arg/NFB) nanocomplex has been prepared and evaluated in vitro and in vivo.The Arg/NFB nanocomplex possesses good antioxidant activities and could modulate the polarization of non-activated macrophage into different types and induce the secretion of pre-inflammato ry,anti-inflammatory,osteogenic as well as angiogenic cytokines.Additionally,the regulated immune microenvironment can enhance the osteogenic differentiation of mouse embryo osteoblast precursor cells(MC3 T3-E1) and angiogenic capacity of human umbilical vein endothelial cells(HUVECs),leading to the improved formation of mineralized nodules,alkaline phosphatase activity and angiogenic effects.In vivo results with cranial defect models reveal that the treatment of Arg/NFB nanocomplex exhibited significant improvement of new bone formation and angiogenesis.All the results demonstrate Arg/NFB nanocomplex with antioxidant activities and osteoimmunomodulatory properties could be a new idea for developing the next generation of bone regeneration biomaterials.     

Study on the reaction mechanism between Pb3O4 and Si in stored silicon delay composition

Journal of Thermal Analysis and Calorimetry - The thermogravimetric techniques and differential thermal analysis have been employed in this work to analyze the macro-reactions mechanism of the...     

The effect of high-power ultrasound on the rheological properties of strawberry pulp

This study investigated the effects of high-power ultrasound (HPU, 0–45 °C, 242–968 W/cm², 2–16 min) on the rheological properties of strawberry pulp. Following the HPU treatment, the strawberry pulp exhibited an increase in apparent viscosity, storage modulus (G′), and loss modulus (G″). The water-soluble pectin (WSP), pectin methylesterase (PME) activity, and free calcium ions (Ca²⁺) of the strawberry pulp after HPU treatment were investigated to determine a possible reason for this phenomenon. HPU caused a significant decrease in the degree of esterification (DE), molecular weight (Mw), and particle size of strawberry WSP, but no significant changes were evident in the galacturonic acid (GalA) content and the zeta (ζ)-potential (P > 0.05), resulting in decrease in the apparent viscosity. Moreover, the largest reduction of PME activity was 22.6% after HPU treatment at 605 W/cm² and 45 °C for 16 min, indicating that the PME was resistant to the HPU treatments. The free Ca²⁺ content in the strawberry pulp was significantly decreased after exposure to HPU (P < 0.05). The maximal reduction of 52.01% in the free Ca²⁺ was achieved at 605 W/cm² and 45 °C for 16 min. The overall results indicated that the high residual activity (RA) of PME after HPU might induce the low esterification of WSP, while HPU promoted the interaction of free Ca²⁺ and low-methylated pectin, to form the network structure of Ca²⁺-low-methylated pectin, resulting in an increase in viscosity in the complex strawberry system.     

CO电子基态P线系跃迁谱线的理论研究

基于微分的思想,结合经典的双原子分子跃迁谱线表达式,提出了预言双原子分子P线系高激发振-转跃迁谱线的新解析物理公式.对于某分子电子体系的某一P支跃迁带,利用实验上获得的一组(15条)精确的跃迁谱线和该跃迁带对应的上下振动态的转动常数(B_υ',B_υ″)的精确数据,该公式不仅可以精确地重复已知的实验跃迁谱线,而且还能预测出实验上难以获得的更高激发态的跃迁谱线数据.利用该公式,研究了CO分子电子基态的(2,0)振-转跃迁带的< 关键词： 双原子分子 发射光谱 P线系')" href="#">P线系 CO     

9,10-2H-9-氧杂-10-磷杂菲-10-氧化物基1,3-苯并噁嗪树脂的合成与表征

以水杨醛、对甲基苯胺(或对氟苯胺,对甲氧基苯胺)、9,10-2H-9-氧-10-磷杂菲-10-氧化物(DOPO)及甲醛为原料,通过三步反应合成了三个含DOPO基的1,3-苯并噁嗪化合物3a-3c.第一步,水杨醛与对位取代苯胺进行缩合反应生成亚胺(1a-1c);第二步,DOPO对亚胺进行加成反应得到仲胺(2a-2c);第三步,仲胺与甲醛在强酸性离子交换树脂催化下进行关环反应形成含DOPO的1,3-苯并噁嗪树脂.采用红外光谱、核磁共振谱和质谱等表征了化合物3a-3c,同时采用热失重分析技术测定了其热稳定性.结果表明,3a-3c由两对对映体组成,质谱条件下2a-2c和3a-3c均经裂解失去稳定的DOPO基团;3a-3c热降解反应包含两个热失重过程,分别在250和400℃下出现最大热释放速率.     

Preparation and characterization of modified graphite oxide/poly(propylene carbonate) composites by solution intercalation

Modified graphite oxide (MGO)/Poly (propylene carbonate) (PPC) composites with excellent thermal and mechanical properties have been prepared via a facile solution intercalation method. An intercalated structure of MGO/PPC composites was confirmed by X-ray diffraction and scanning electron microscope. The thermal and mechanical properties of MGO/PPC composites were investigated by thermal gravimetric analysis, differential scanning calorimetric, dynamic mechanical analysis, and electronic tensile tester. Due to the nanometer-sized dispersion of layered graphite in PPC matrix and the strong interfacial interaction between MGO and PPC, the prepared MGO/PPC composites exhibit improved thermal and mechanical properties in comparison with pure PPC. Compared with pure PPC, the MGO/PPC composites show the highest thermal stability and the T_g is 13.8 °C higher than that of pure PPC, while the tensile strength (29.51 MPa) shows about 2 times higher than that of pure PPC when only 3.0 wt.% MGO is incorporated. These results indicate that this approach is an efficient method to improve the properties of PPC.     

Synthesis and application of chiral N, N'-dialkylated cyclohexanedi- amine for asymmetric hydrogenation of aryl ketones

Chiral N, N'-dialkylated cyclohexanediamine derived ligands have been synthesized and used in the asymmetric hydrogenation of aryl ketones. Optically active alcohols with up to 90% enantiomeric excess were obtained in high yields.     

Largely enhanced ductility of immiscible high density polyethylene/polyamide 6 blends via nano‐bridge effect of functionalized multiwalled carbon nanotubes

Immiscible polymer blends usually exhibit negative deviation in mechanical properties compared with the corresponding pure polymers due to the weak interfacial bonding between the two polymers. Due to the bridge effect of the oriented carbon nanotubes (CNTs) on the craze and crack development at the load of stress, CNTs have been proved to be efficient toughening agent for polymers. In this work, functionalized multiwalled carbon nanotubes (FMWCNTs) have been introduced into immiscible high density polyethylene/polyamide 6 (HDPE/PA6) blends through different sample preparation methods. The mechanical measurements demonstrate that, when the nanocomposite is prepared from the HDPE master batch, the sample exhibits excellent tensile strength and toughness simultaneously. For all the nanocomposites, FMWCNTs tend to migrate and/or maintain in PA6 particles, leading to the variation of the crystallization behavior in PA6 phase. Further results based on morphologies characterization indicate that the intensified interfacial adhesion between HDPE and PA6, which is realized by the nano‐bridge effect of FMWCNTs in the interfaces, is the main reason for the largely improved ductility. Copyright © 2010 John Wiley & Sons, Ltd.