Preparation of azafullerene derivatives from fullerene-mixed peroxides and single crystal X-ray structures of azafulleroid and azafullerene

Azafullerene was prepared by addition of hydroxylamine to a cage-opened fullerendione derivative and subsequent PCl5 induced rearrangement processes. X-ray structures were obtained for the azafullerene and its azafulleroid precursor.     

Characterization of Column Hold-Up Volume with Static and Dynamic Methods on an Immobilized Polysaccharide-Based Chiral Stationary Phase

Polysaccharide-based chiral stationary phases (CSPs) are efficient for enantioseparation of many chiral compounds. Immobilized polysaccharide CSP, as used in the Chiralpak IA column, is a new configuration that was recently introduced for application in chiral separation. As shown in several previous studies, the characteristics of Chiralpak IA columns cannot be simply extrapolated from the coated version. In this study, hold-up volume of a Chiralpak IA column was evaluated by static and dynamic methods. The static pyconometry method gave similar hold-up volumes either as an average value from a range of solvents or a direct measurement from the carbon tetrachloride-isopropanol (IPA) solvent pair. The dynamic method with 1,3,5-tri-tert-butylbenzene (TTBB) was influenced by the ratio of n-hexane and 2-propanol in the mobile phase but not by the dissolving solvent of TTBB. The two methods resulted in the same hold-up volume of ∼3.0 mL. TTBB showed weaker retention on the IA column after correction of isobaric thermal expansion of the mobile phase. During temperature variations in the range of 15–50 °C, the hold-up volume of TTBB was highly reproducible. Results of this study improve our understanding of the chromatographic features of the immobilized polysaccharide IA column.     

Constituents from Leaves of Scolopia chinensis

Two new phenolic glycosides, scolochinenosides A and B ( 1 and 2 ), and a new flavonoid glycoside, scoloside A ( 3 ), were isolated from the leaves of Scolopia chinensis (Lour .) Clos , together with eight known compounds. The structures of the new compounds were established on the basis of chemical and spectroscopic evidences.     

第34届环境分析化学国际会议 (Ⅱ)

2006年6月5日18时举行国际环境分析化学协会大会。Roland WFrei奖则由下述论文报告中评出:(1)B Docekal等,应用原于发射光谱技术监测大气气溶胶的元素组成用的电聚焦浓集器件;(2)NLuque等,在以带阴电荷胶束为基础的凝聚层中两亲(亲水与亲油)与疏水性污染物的稳定性;(3)KBadnarik等,聚氨酯泡沫材料的生态毒物学评估;(4)D C Cullen等,应用磁珠的、供污染物的化学发光光学检测用的微流体传感器;(5)V GMihucz等,应用扇区感耦等离子体-质谱技术测定人尿中铂;(6)E MCukrowska等,研究环境基质中重金属形态分析用的、有支撑的液膜萃取探针;(…     

An Effective Non-Enzymatic Glucose Biosensor Based on Nanostructured CuxO/Cu Electrodes Synthesized in Situ by Copper Anodization

Potentiostatic anodization was developed to synthesize copper oxide/copper (Cu_xO/Cu, x=1,2) electrode with nano structure for sensitive non-enzymatic glucose detection. At a catalytic potential of 0.55 V, the CuO/Cu electrode presented a high sensitivity of 2954.38 μA mM⁻¹ cm⁻² to glucose and a linear range of 0.1 mM to 1.3 mM. The response time is less than 3 s with addition of 0.1 mM glucose. The CuO/Cu electrode above was anodized in 1M KOH solution at −100 mV and the morphology was compact nanoparticles and sparsely dispersed nanosheets, which enlarged the surface area and provided abundant electrocatalytic active sites. Compared the sensing property of electrodes with different morphologies, it indicated that nanostructure was significant to the efficient glucose catalytic oxidation process and it could be regulated by changing the potential and electrolyte concentration during anodization.     

pH Responsive Poly(Amino Acid) Nanoparticles as Potent Carrier Adjuvants for Enhancing Cellular Immunity

Adjuvants are widely used in vaccine to improve the protection or treatment efficacy. However, so far they inevitably produce side effects and are hard to induce cellular immunity in practical application. Herein, two kinds of amphiphilic poly(glutamic acid) nanoparticles (α-PGA-F and γ-PGA-F NPs) as nanocarrier adjuvants are fabricated to induce an effective cellular immune response. Amphiphilic PGA are synthesized by grafting phenylalanine ethyl ester to form biodegradable self-assembly nanoadjuvants in a water solution. The model antigen, chicken ovalbumin (OVA), can be loaded into PGA-F NPs (OVA@PGA-F NPs) with the high loading ratio >12%. Moreover, compared with γ-PGA-F NPs, the acidic environment can induce the α-helical secondary structure of α-PGA NPs, promoting membrane fusion and more fast antigen lysosomal escape. Hence, the antigen presenting cells treated with OVA@α-PGA-F NPs show higher secretion of inflammatory cytokines, and higher expression of major biological histocompatibility complex class I and CD80 than those of OVA@γ-PGA-F NPs. Overall, this work indicates that pH responsive α-PGA-F NPs as a carrier adjuvant can effectively improve the ability of cellular immune responses, leading to it being a potent candidate for vaccine applications.     

Synthesis and liquid crystalline behaviour of substituted (E)-phenyl-4-(phenyldiazenyl) benzoate derivatives and their photo switching ability

Azobenzene derivatives containing phenyl/4-halogen-phenyl 4-{(E)-[4-(pent-4-en-1-yloxy)phenyl]diazenyl}benzoate group with different electronegative substituent (H, F, Cl, Br and I) at other end was synthesised. These azo-based benzoate derivatives have been characterised by FTIR, ¹H-NMR, ¹³C-NMR, elemental analyser, POM and UV-Vis spectroscopy. Photosaturation at 358 nm obtained after 82 s of UV irradiation and the longest thermal back relaxation time of 45 h recorded by UV-Vis. The azo derivative could be possible photolock under UV light, as observed by the improved thermal back relaxation time. The resulting photolockable chain of azobenzene might prove valuable in the development of optical device application. These azobenzene moieties also exhibit liquid crystalline behaviour with respect to the halogen substitution as an electron withdrawing group shows that strong structure property relationship exists among them.     

Enhanced β Crystalline Phase in Poly(vinylidene fluoride) via the Incorporation of Graphene Oxide Sheets assisted by Supercritical CO2 Treatment

Graphene oxide (GO) sheets were pre-modified with a typical piezoelectric polymer, poly(vinylidene fluoride) (PVDF), using a simple supercritical carbon dioxide (SC CO₂) method, and then the PVDF-decorated GO was added into a PVDF matrix by solution blending. Transmission electron microscopy (TEM) revealed that the decorating degree of PVDF on the surface of the GO increased significantly with increasing of SC CO₂ pressure and PVDF concentration. The mechanism of the polymer adsorption on the GO sheets through favorable interaction between the GO and PVDF chains was identified via Fourier transform infrared spectroscopy (FTIR). Further, the crystallization behavior of PVDF/GO composites was investigated by differential scanning calorimetry (DSC), FTIR and polarized optical microscopy (POM). Interestingly, the composite with PVDF-decorated GO as the filler showed higher β-phase content compared to the composite with pristine GO as the filler. The study showed that the supercritical fluid-induced epitaxial crystallization process has significant potential for fabricating functional GO-based nanocomposties containing piezoelectric or conducting materials.     

Mutually Unbiasedness between Maximally Entangled Bases and Unextendible Maximally Entangled Systems in $\mathbb {C}^{2}\otimes \mathbb {C}^{2^{k}}$

The mutually unbiasedness between a maximally entangled basis (MEB) and an unextendible maximally entangled system (UMES) in the bipartite system \(\mathbb {C}^{2}\otimes \mathbb {C}^{2^{k}} (k>1)\) are introduced and discussed first in this paper. Then two mutually unbiased pairs of a maximally entangled basis and an unextendible maximally entangled system are constructed; lastly, explicit constructions are obtained for mutually unbiased MEB and UMES in \(\mathbb {C}^{2}\otimes \mathbb {C}^{4}\) and \(\mathbb {C}^{2}\otimes \mathbb {C}^{8}\), respectively.     

Protein‐Affinitive Polydopamine Nanoparticles as an Efficient Surface Modification Strategy for Versatile Porous Scaffolds Enhancing Tissue Regeneration

Porous scaffolds for tissue regeneration are often functionalized with extracellular matrix proteins to enhance surface/cell interactions and tissue regeneration. However, continuous coatings produced by commonly used surface modification strategies may preclude cells from contacting and sensing the chemical and physical cues of the scaffold. Here, it is shown that polydopamine nanoparticles (PDA‐NPs) tightly adhere on various scaffolds to form nanostructures, and the coverage can be finely tuned. Furthermore, the PDA‐NPs have good affinity to a variety of proteins and peptides. Thus, the PDA‐NPs act as an anchor to immobilize signal biomolecules on scaffolds, and consequently promote cell activity and tissue regeneration. β‐Tricalcium phosphate (TCP) scaffolds decorated with PDA‐NPs demonstrate excellent osteoinductivity and bone‐regeneration performance due to the protein affinity of PDA‐NPs and the intrinsic bioactive characteristics of TCP scaffolds. In summary, PDA‐NPs with excellent affinity for protein adhesion represent a versatile platform to modify porous scaffolds while not compromising the biological functions of the scaffolds, and might have potential applications in tissue regeneration.