Controlled Release of Curcumin via Folic Acid Conjugated Magnetic Drug Delivery System

In the paper, folic acid(FA)-mediated and β-cyclodextrin(β-CD) derivatives functionalized magnetic Fe₃O₄ nanoparticles(MNPs) were successfully prepared as drug carriers for the targeted delivery and controlled release of water-insoluble anticancer drug. FA-sulfobutyl ether-β-CD-MNPs(FA-SBE-β-CD-MNPs), FA-hydroxypropyl-β-CD-MNPs(FA-HP-β-CD-MNPs) and FA-carboxymethyl-β-CD-MNPs(FA-CM-β-CD-MNPs) were fabricated, and the loading efficiency and relative entrapment rate of curcumin are 12.04 mg/g, 95.56% for FA-SBE-β-CD-MNPs, 9.6 mg/g, 81.63% for FA-HP-β-CD-MNPs and 7.88 mg/g, 85.28% for FA-CM-β-CD-MNPs, respectively. Meanwhile, at pH=5.0, the optimal release rate of curcumin is about 46.07% for FA-SBE-β-CD-MNPs in 5 h. Cellular uptake indicates that curcumin can be selectively transported to targeting site and released from the internalized carriers. The in vitro cytotoxicity reveals that non-toxic FA-SBE-β-CD-MNPs have excellent biocompatibility on HepG2 cells in the tested concentrations. Therefore, FA-SBE-β-CD-MNPs could provide a promising platform for the targeting delivery of water insoluble anti-cancer drugs for different treatment needs of cancer therapy.     

Finite-temperature scaling of quantum coherence near criticality in a spin chain

We explore quantum coherence, inherited from Wigner-Yanase skew information, to analyzequantum criticality in the anisotropic XY chain model at finite temperature. Based on theexact solutions of the Hamiltonian, the quantum coherence contained in a nearest-neighborspin pairs reduced density matrix ρ is obtained. The first-order derivative of thequantum coherence is non-analytic around the critical point at sufficient low temperature.The finite-temperature scaling behavior and the universality are verified numerically. Inparticular, the quantum coherence can also detect the factorization transition in such amodel at sufficient low temperature. We also show that quantum coherence contained indistant spin pairs can characterize quantum criticality and factorization phenomena atfinite temperature. Our results imply that quantum coherence can serve as an efficientindicator of quantum criticality in such a model and shed considerable light on therelationships between quantum phase transitions and quantum information theory at finitetemperature.     

Nano Si preparation by constant cell voltage electrolysis of FFC-Cambridge Process in molten CaCl₂

Using FFC-Cambridge Process to prepare Si from SiO2 is a promising method to prepare nanostructured and highly pure silicon for solar cells.However,the method still has many problems unsolved and the controlling effect of the cell voltage on silicon product is not clear.Here we report in this article that nano cluster-like silicon product with purity of 99.95%has been prepared by complete conversion of raw material SiO2,quartz glass plate,using constant cell voltage electrolysis FFC-Cambridge Process.By analysis of XRD,EDS,TEM,HRTEM and ICP-AES as well as the discussion from the thermodynamics calculation,the morphology and components of the product based on the change of cell voltage are clarified.It is clear that pure silicon could be prepared at the cell voltage of 1.7 2.1 V in this reaction system.The silicon material have cluster-like structure which are made of silicon nanoparticles in 20 100 nm size.Interestingly,the cluster-like nano structure of the silicon can be tuned by the used cell voltage.The purity,yield and the energy cost of silicon product prepared at the optimized cell voltage are discussed.The purity of the silicon product could be further improved,hence this method is promising for the preparation of solar grade silicon in future.     

C–C bridged Ni(II) complexes bearing β‐keto‐9‐fluorenyliminato ligands prepared by different in situ bonding mechanisms and their use in catalytic (co)polymerization of norbornene and styrene

Two C–C bridged Ni(II) complexes bearing β‐keto‐9‐fluorenyliminato ligands with electron‐withdrawing groups (─CF₃), Ni{PhC(O)CHC[N(9‐fluorenyl)]CF₂}₂ (Ni 1 ) and Ni{CF₃C(O)CHC[N(9‐fluorenyl)]Ph}₂ (Ni 2 ), were synthesized by metal coordination reaction and different in situ bonding mechanisms. The C–C bridged bonds of Ni 1 were formed by in situ intramolecular trifluoromethyl and 9‐fluorenyl carbon–carbon cross‐coupling reaction and those of Ni 2 were formed by in situ intramolecular 9‐fluorenyl carbon–carbon radical coupling reaction mechanism. The obtained complexes were characterized using ¹H NMR spectroscopy and elemental analyses. The crystal and molecular structures of Ni 1 and Ni 2 with C–C bridged configuration were determined using X‐ray diffraction. Ni 1 and Ni 2 were used as catalysts for norbornene (NB) polymerization after activation with B(C₆F₅)₃ and the catalytic activities reached 10⁶ g_polymer mol_Ni^?1 h^?1. The copolymerization of NB and styrene catalyzed by the Ni 1 /B(C₆F₅)₃ system showed high activity (10⁵ g_polymer mol_Ni^?1 h^?1) and the catalytic activities decreased with increasing feed content of styrene. All vinyl‐type copolymers exhibited high molecular weight (10⁴ g mol^?1), narrow molecular weight distribution (M_w/M_n = 1.71–2.80), high styrene insertion ratios (11.13–50.81%) and high thermal stability (T_d > 380°C) and could be made into thin films with high transparency in the visible region (400–800 nm).     

Nickel complexes bearing different electron groups on substituted salicylaldnaphthylmethyleneimine ligands: Syntheses and their catalytic performance for (co)polymerization of norbornene

Novel nickel complexes bearing different electron groups on substituted salicylaldnaphthylmethyleneimine ligands, bis-(salicylaldnaphthylmethyleneimino)Ni(II) (Ni{(3-R¹)(5-R²)C₆H₂(O)CH[N (naphthyl-CH₂)]}₂ Ni1 : R¹ = H, R² = H; Ni2 : R¹ = H, R² = CH₃; Ni3 : R¹ = H, R² = Br; Ni4 : R¹ = H, R² = OCH₃; Ni5 : R¹ = CH₃, R² = H; Ni6 : R¹ = Br, R² = H), were synthesized. Ni2 , Ni3 , Ni5 , and Ni6 are clearly characterized by single-crystal X-ray diffraction. Co-polymerization of norbornene (NB) with 5-norbornene-2-methylene butyl ether (BN) was carried out in toluene with the aforesaid complexes as catalyst precursors and B(C₆F₅)₃ as the co-catalyst. Catalyst activity, molecular weight, thermal stability, solubility, regularity, and optical transparency were investigated, and the mechanism of the electron groups changing catalyst performance is explained. All catalysts show high activity toward co-polymerization (up to 3.53 × 10⁵ g_polymer mol_Ni⁻¹ h⁻¹). Ni3 shows the highest activity and Ni5 shows the highest insertion rate (up to 37.6%). The obtained poly(NB-co-BN)s are confirmed to be vinyl-addition-type co-polymers, and they are noncrystalline. The co-polymers exhibited excellent thermal stability and processability (T_d ≥ 400 °C, T_g < 240 °C), optical transparency (up to 90%), and good solubility.     

Synthesis of cellulose benzoates under homogeneous conditions in an ionic liquid

The ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) as a reaction medium was studied for the synthesis of cellulose benzoates by homogeneous acylation of dissolved cellulose with benzoyl chlorides in the absence of any catalysts. Cellulose benzoates with a degree of substitution (DS) in the range from about 1 to 3.0 were accessible under mild conditions. The DS of cellulose derivatives increased with the increase of the molar ratio of benzoyl chloride/anhydroglucose unit (AGU) in cellulose, reaction time, and reaction temperature. Benzoylation of cellulose with some 4-substituted benzoyl chlorides including 4-toluoyl chloride, 4-chlorobenzoyl chloride and 4-nitrobenzoyl chloride was also readily carried out under mild conditions. Furthermore, regioselectively substituted mixed cellulose esters were synthesized in this work. All products were characterized by means of FT-IR, ¹H-NMR, and ¹³C-NMR spectroscopy. In addition, at the end of benzoylation of cellulose, the ionic liquid AmimCl was easily recycled. When the recycled AmimCl was used as the reaction media, the cellulose benzoate with a similar DS was obtained under comparable reaction conditions.     

中位取代苯硼酸的含稠合外环的硼-二吡咯亚甲基染料类单糖荧光探针的合成与性能

以环己烯为起始原料,首先经过两步改进的合成方法制备出2-乙氧羰基-3,4-四亚甲基吡咯,并用过量氢化铝锂将其高温还原得到2-甲基-3,4-四亚甲基吡咯,后者与被保护的4-甲醛基苯硼酸在三氟乙酸的催化作用下发生缩合反应,用2,3-二氯-5,6-二氰基-1,4-苯醌(DDQ)氧化并依次用三乙胺和三氟化硼-乙醚处理后,得到一种新型的中位取代苯硼酸的含稠合外环的硼-二吡咯亚甲基类(BDP)染料衍生物。 通过紫外-可见吸收光谱及荧光光谱滴定方法,研究了该染料在特定pH值下对D-果糖、D-半乳糖、D-葡萄糖等3种单糖的响应能力,上述3种单糖与BDP染料衍生物的键合既表现在吸收光谱上,也表现在荧光发射光谱上,并且通过对荧光滴定数据的非线性拟合分析,BDP染料衍生物1与D-果糖、D-半乳糖、D-葡萄糖的结合常数分别为1045、445和130 L/mol。 因此该染料衍生物作为单糖的荧光探针,具有灵敏度高、选择性较好等优点;另外,还初步探讨了该荧光探针的传感机理。     

含有手性BINAP基团的共轭微孔聚合材料应用于喹啉高效不对称氢化反应

喹啉不对称氢化反应是不对称氢化研究的重点之一。其氢化产物四氢喹啉不仅是重要的有机合成中间体,同时也是自然界中生物碱的结构单元和生物活性化合物。周永贵研究组首次报道了手性(R)-MeO-Biphep/Ir体系成功用于喹啉的不对称催化,取得了非常好的反应结果。随后他们对喹啉底物进行了拓展,包括拥有特殊取代基的喹啉衍生物,均取得了良好的反应结果。后来多个研究组对该反应进行了深入研究并开发出了多个不同手性膦配体的Ir催化体系。虽然喹啉不对称氢化反应取得了很大的发展,但是该均相反应体系只能在高的反应催化剂用量下才能实现好的结果。进一步研究发现手性配体与金属Ir络合后形成反应活性物种,但后者可发生二聚或三聚,生成的产物是不具有催化活性的,从而导致了反应体系需要高的催化剂的用量。为此人们做了大量研究。范青华研究组通过对BINAP基团上嫁接大空间位阻的枝状分子合成了一系列新的手性BINAP配体,在与Ir络合后,表现出远高于均相催化剂的反应活性,且可循环利用。在该体系中,大位阻的枝状分子起到了阻隔活性物种二聚、三聚的作用,因而提高了反应活性。后来周永贵研究组也尝试通过改变有机配体的方法来实现高的反应活性。他们选择改变手性双膦配体上P原子所连接有机配体的空间位阻来实现对活性物种多聚的控制。实验同样取得了很好的反应效果。对于均相反应体系,我们只能通过这种改变有机配体空间位阻的方式来降低活性物种多聚的可能性,那么如何彻底阻止这种多聚呢？非均相体系给我们提供了很好的研究思路,但如何将非均相体系引入到喹啉不对称氢化反应体系当中成为了难点。
　　共轭微孔聚合物(CMPs)的发展使得手性催化体系很容易从均相转变到非均相。这种材料具有较高的比表面积和固定的开放孔道结构,可应用于非均相催化中。且制备相对容易。我们可以将手性双膦配体作为材料制备配体嫁接到CMPs材料当中。在这种材料当中,手性配体会以有序、空间分离的方式分布,在与Ir配合后应用于喹啉不对称氢化反应中,从而从根本上避免了活性物种多聚的可能因此反应活性提高。我们曾首次成功合成了一系列含有手性(R)-Binap基团的共轭微孔聚合材料-BINAP-CMPs,并将其用于β-酮酸酯的不对称氢化反应当中,取得了很好的催化效果。手性BINAP基团均匀、有序地分散于该材料中。我们尝试利用BINAP-CMPs固有的空间隔离效应,将其应用于喹啉的不对称氢化反应中,结果表明,在相同条件下,非均相BINAP-CMPs/Ir催化体系的TOF值是340 h–1,是均相BINAP/Ir体系(100 h–1)3倍,反应的对映体选择性与均相相当;另外该催化体系多循环利用次后仍可以保持高的反应活性。我们还发现材料结构性质对反应结果的影响很大,材料的比表面积和孔容更大反应结果更好。     

两注THz折叠波导行波结构的增益与传输特性

为了提高太赫兹行波管的输出功率,提出了多个传输信号进行功率合成的方法。首先,对D波段多注慢波结构进行设计及功分器的优化;然后,通过微铣削工艺完成了两注THz折叠波导结构的加工,加工精度满足实际设计要求;最后,利用CST软件对该结构的冷测与互作用特性进行了分析。仿真结果表明：该结构的S11值小于-20 dB,实际测试值在-20 dB左右,两者较吻合。冷测分析表明该结构具有22 GHz（16%）的冷带宽,3 dB增益带宽为12.5 GHz。在各电子注的电压、电流、峰值输入功率大小分别为15.79 kV, 12 mA, 10 mW时,单注结构获得了1.58 W的输出功率及22 dB的增益;而两路信号在互作用完成后,获得了2.91 W的合成功率输出,合成效率不低于90%。通过合成的方法可以有效提高THz行波管的输出功率。.