聚左旋乳酸/聚消旋乳酸共混物的结晶行为

非晶态聚消旋乳酸(PDLLA)对PLLA的结晶行为有较大的影响。本文利用差示扫描量热仪(DSC)和偏光显微镜(POM)对不同分子量PLLA、PDLLA按不同比例制得的共混物结晶进行了系统研究。结果表明随PDLLA含量的增大PLLA冷结晶温度升高,且越接近熔融温度。PDLLA分子量较小时PLLA球晶特征被明显破坏,PDLLA分子量较大时PLLA更易形保持球晶特征且易形成环带球晶形貌,这与结晶速率与非晶组分的扩散速率匹配程度有关。低分子量的PDLLA使PLLA的最大生长速率对应的温度出现在较低温度。     

Redox-Guest-Induced Multimode Photoluminescence Switch for Sequential Logic Gates in a Photoactive Coordination Cage

Molecular or supramolecular level photoluminescence (PL) modulation combining chemical and photonic input/output signals together in an integrated system can provide potential high-density data memorizing and process functions intended for miniaturized devices and machines. Herein, a PL-responsive supramolecular coordination cage has been demonstrated for complex interactions with redox-active guests. PL signals of the cage can be switched and modulated by adding or retracting Fc derivatives or converting TTF into different oxidation states through chemical or photochemical pathways. As a result, reversible or stepwise PL responses are displayed by these host–guest systems because of the occurrence of photoinduced electron-transfer (PET) or fluorescence resonance energy transfer (FREnT) processes, providing unique nanodevice models bearing off/on logic gates or memristor-like sequential memory and Boolean operation functions.     

Self-Healable Polyelectrolytes with Mechanical Enhancement for Flexible and Durable Supercapacitors

The practical application of advanced personalized electronics is inseparable from flexible, durable, and even self-healable energy storage devices. However, the mechanical and self-healing performance of supercapacitors is still limited at present. Herein, highly transparent, stretchable, and self-healable poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA)/poly(vinyl alcohol) (PVA)/LiCl polyelectrolytes were facilely prepared by one-step radical polymerization. The cooperation of PAMPSA and PVA significantly increased the mechanical and self-healing capacity of the polyelectrolyte, which exhibited superior stretchability of 938 %, stress of 112.68 kPa, good electrical performance (ionic conductivity up to 20.6 mS cm⁻¹), and high healing efficiency of 92.68 % after 24 h. After assembly with polypyrrole-coated single-walled carbon nanotubes, the resulting as-prepared supercapacitor had excellent electrochemical properties with high areal capacitance of 297 mF cm⁻² at 0.5 mA cm⁻² and good rate capability (218 mF cm⁻² at 5 mA cm⁻²). Besides, after cutting in two the supercapacitor recovered 99.2 % of its original specific capacitance after healing for 24 h at room temperature. The results also showed negligible change in the interior contact resistance of the supercapacitor after ten cutting/healing cycles. The present work provides a possible solution for the development of smart and durable energy storage devices with low cost for next-generation intelligent electronics.     

Octacarbonyl Ion Complexes of Actinides [An(CO)8]+/− (An=Th,U) and the Role of f Orbitals in Metal–Ligand Bonding

The octacarbonyl cation and anion complexes of actinide metals [An(CO)₈]^+/− (An=Th, U) are prepared in the gas phase and are studied by mass-selected infrared photodissociation spectroscopy. Both the octacarbonyl cations and anions have been characterized to be saturated coordinated complexes. Quantum chemical calculations by using density functional theory show that the [Th(CO)₈]⁺ and [Th(CO)₈]⁻ complexes have a distorted octahedral (D_4h) equilibrium geometry and a doublet electronic ground state. Both the [U(CO)₈]⁺ cation and the [U(CO)₈]⁻ anion exhibit cubic structures (O_h) with a ⁶A_1g ground state for the cation and a ⁴A_1g ground state for the anion. The neutral species [Th(CO)₈] (O_h; ¹A_1g) and [U(CO)₈] (D_4h; ⁵B_1u) have also been calculated. Analysis of their electronic structures with the help on an energy decomposition method reveals that, along with the dominating 6d valence orbitals, there are significant 5f orbital participation in both the [An]←CO σ donation and [An]→CO π back donation interactions in the cations and anions, for which the electronic reference state of An has both occupied and vacant 5f AOs. The trend of the valence orbital contribution to the metal–CO bonds has the order of 6d≫5f>7s≈7p, with the 5f orbitals of uranium being more important than the 5f orbitals of thorium.     

5 nm Ordered Structures Self-Assembled by C2-Symmetric Hybrids with Polyhedral Oligomeric Silsesquioxane and Hexa-peri-Hexabenzocoronene.

Hybrids consisting of polyhedral oligomeric silsesquioxane (POSS) and hexa-peri-hexabenzocoronene (HBC) with a dumbbell topology and C₂ symmetry were designed and synthesized. They self-assemble into 5 nm ordered structures. In particular, the increased steric effect with increasing POSS units stabilizes a square columnar phase (Col_squ) which is important in nanotemplating. These hybrids containing discotic liquid crystal HBC and POSS units have an excellent etching contrast and present an approach to obtain 5 nm nanopatterns.     

Porous carbon nanospheres with moderately oriented domains for EDLC electrode

Porous carbon nanospheres with moderately oriented microcrystalline structures were prepared via a relatively simple synthetic route in this article. CTAB acted as a structure‐directing agent to induce small sulfonated pitch (SP) pieces to assemble orderly. By this means, the formation of carbon nanospheres was simultaneous with the moderate orientation of carbon microcrystalline without additional process. Owing to the moderately oriented microcrystalline structures, the resultant sample CNS3 possessed a high e‐conductivity of 62.5 S/m. When used as an electrode material for EDLCs, it showed excellent electrochemical properties even without any conductive agent. In an organic electrolyte, the resultant sample CNS3 possessed a high specific capacitance of 155 F/g at 20 A/g and outstanding cycle life with 94.2% capacity retention after 10,000 cycles. This work puts forward a novel design for carbon nanospheres with moderately oriented domains by a simple and energy‐efficient means.     

Synthesis and Antitumor Effect of Sophoridine Derivatives Bearing an Acyclic Aryloxy Phosphoramidate Mustard Functionality

To elevate the potency of sophoridine, phosphoramidate mustard motif was incorporated to D‐ring opened sophoridine scaffold. A series of acyclic aryloxy phosphoramidate mustard functionalized sophoridine derivatives were synthesized and screened for cytostatic activity in a range of different tumor cell lines (S180, H22, K562, MCF‐7, SMMC‐7721, and LoVo). All these compounds were shown to be more sensitive to S180 and H22 cells with IC₅₀ values ranging from 2.10 to 7.21 μM. In addition, all targeted derivatives distinctly are more cytotoxic to cancer cells than normal cell L929. Compounds 8b , 8c , 8d , and 8e displayed moderate tumor suppression without apparent organ toxicity in vivo against mice bearing H22 liver tumors. Their potential binding modes with DNA topoisomerase I complex have also been investigated.     

Separation and purification of lanosterol,dihydrolanosterol, and cholesterol from lanolin by high‐performance counter‐current chromatography dual‐mode elution method

Lanosterol is a potential drug for cataracts treatment, which can reverse the aggregation of intracrystalline proteins. The low concentration in lanolin calls for high‐performance separation methods. In this study, a counter‐current chromatography dual‐mode elution method was developed for the first time to separate and purify lanosterol from hexane extract of lanolin after saponification, in which the column was first eluted with the lower phase as mobile phase in head‐to‐tail mode, followed by the upper phase in the tail‐to‐head mode. High purity of lanosterol, dihydrolanosterol, and cholesterol can be obtained simultaneously. A solvent system composed of n‐heptane/acetonitrile/ethyl acetate (5:5:1, v/v/v) was selected and optimized via partition coefficient determination. Compounds such as 111 mg lanosterol, 84 mg dihydrolanosterol, and 183 mg cholesterol with high purity of 99.77, 95.71, and 91.43%, respectively, analyzed by high‐performance liquid chromatography were obtained within 80 min from 700 mg crude extract from 1.78 g lanolin. The method was also used to improve the purity of commercial lanosterol product from 66.97 to above 99%. Counter‐current chromatography could serve as a potential and powerful technique for commercial production of highly pure lanosterol.     

Metabolomic analysis of raw Pinelliae Rhizoma and its alum‐processed products via UPLC–MS and their cytotoxicity

Alum‐processing is a traditional method to attenuate the toxicity of Pinelliae Rhizoma (tubers of Pinellia ternate, PT). The present study aimed at investigating the chemical and cytotoxic changes during alum processing. Metabolomic profiles of raw and alum‐processed PT were studied based on ultra‐performance liquid chromatography coupled with Orbitrap mass spectrometry. More than 80 chemicals in positive MS mode and 40 chemicals in negative MS mode, such as organic acids, amino acids, glucosides and nucleosides, were identified after multivariate statistical analysis, including principal component analysis and orthogonal partial least‐square discriminant analysis. Almost all of the identified chemical markers were significantly decreased ~10‐ to 100‐fold after alum processing. Meanwhile, the correlations between the chemical markers were assimilated to a positive coefficient from disorderly distribution during the processing. Raw PT extracts could inhibit the proliferation of human carcinoma cells (HCT‐116, HepG2, and A549) at the rate of 40.5, 24.8 and 31.6% more strongly than processed PT. It was concluded that the alum processing of PT could decrease the number of actively water‐soluble principles at the same time as decreasing toxicity. Given the water‐insoluble property of toxic calcium oxalate raphides in PT, we suggest that a more scientific processing method should be sought.     

Qualitative and quantitative determination of Atractylodes rhizome using ultra‐performance liquid chromatography coupled with linear ion trap–Orbitrap mass spectrometry with data‐dependent processing

A quick and effective workflow based on ultra‐performance liquid chromatography coupled with electron spray ionization and LTQ‐Orbitrap mass spectrometry (UPLC‐LTQ‐Orbitrap MS) was established for compositional analysis and screening of the characteristic compounds of three species of Atractylodes rhizome for quality evaluation. This technique was employed to determine the seven main components in Atractylodes rhizome samples. Ultimately, 78 constituents were identified; of these, seven characteristic compounds were selected for species discrimination, comprising atractylodin (63), atractylenolide I (43), atractylenolide II (49), atractylenolide III (53), atractylon (69), methyl‐atractylenolide II (54) and (4E,6E,12E)‐tetradecadecatriene‐8,10‐diyne‐1,3‐diacetate (59). The seven main compounds, including six characteristic compounds, were simultaneously determined in 29 batches of Atractylodes rhizome samples. Thus, the method validation showed acceptable results. Quantitative analysis showed significantly different contents of the seven main components among the three species of Atractylodes rhizome, which indicates possible distinctions in the pharmacological effects. This established method can simultaneously provide qualitative and quantitative results for compositional characterization of Atractylodes rhizomes and for quality control.