An investigation of the complexation of host <Emphasis Type="Italic">N,N′</Emphasis>-bis(9-phenyl-9-thioxanthenyl)ethylenediamine with dihaloalkane guests

In this study, the formation of supramolecular inclusion complex of doxorubicin (DOX), a high loading and pH-dependent delivery of DOX on β-CD dendrimer was studied. β-cyclodextrin (β-CD) dendrimer having β-CD in both periphery and core was prepared with entrapment efficiency using click reaction. The encapsulation property of the β-CD-dendrimer was investigated by DOX as model drug. The chemical construction of β-CD-dendrimer was described by ¹H NMR, ¹³C NMR and FTIR and its inclusion complex construction was studied by FTIR, DSC, SEM, and DLS techniques. It was confirmed that β-CD dendrimer able to encapsulate DOX in solution; as a result, the designed complex revealed pH-dependent sustained release of DOX, in vitro. Also, the in vitro outcomes on T47D cells displayed that complexation of DOX with β-CD dendrimer involved an improvement of in vitro cytotoxicity and anticancer activity and this data appeared to be as a result of the developed solubility of the DOX.     

Induced solvent chirality: A VCD study of camphor in CDCl3

It is shown how the presence of a chiral compound in solution induces chirality in the surrounding solvent molecules. Using Vibrational Circular Dichroism on camphor dissolved in deuterated chloroform, it is found that the C–D stretch in the latter indeed becomes VCD active. The experimental results agree with ab initio computed spectra for 1:1 associations between the solvent and solute.     

Neurovegetative symptoms and complaints before and after voice therapy for nonorganic habitual dysphonia

In a previous study, female patients in all age categories with a nonorganic dysphonia were found to report significantly more autonomic symptoms and complaints than healthy controls. This could not be confirmed for the male subgroup. The present study is to corroborate and nuance this observation by investigating larger groups, and to determine if, after voice therapy, the number of autonomic symptoms and complaints-particularly those ones that have no obvious relation to voice function-decreases. It is a prospective study with a matched control group; 184 patients with nonorganic dysphonia and 126 normal controls answered a questionnaire of 46 questions with 3 subsets and a consistency control. One hundred and one patients received functional voice therapy and completed the questionnaire before and after treatment. A matched control group of 42 normal subjects also filled in the questionnaire two times, with an interval of about 6 months. Neurovegetative symptoms and complaints-voice related and not related-are reported in highly significant excess by patients (especially but not exclusively females) with habitual nonorganic voice disorder. After therapy, there is a highly significant reduction in the number of autonomic symptoms and complaints (related or not related to voice), to such an extent that patients report on average no more general neurovegetative symptoms and complaints than healthy controls (even less). The number of neurovegetative symptoms and complaints connected with voice function is also strongly reduced in patients after therapy, but remains in significant excess when compared with controls.     

A comparison of the behaviour of two closely related xanthenyl-derived host compounds in the presence of vaporous dihaloalkanes

The behaviour of two closely related xanthone-derived host compounds, N,N’-bis(9-phenyl-9-xanthenyl)ethylenediamine and N,N′-bis(9-phenyl-9-thioxanthenyl)ethylenediamine, which formed complexes with CH₂Cl₂, CH₂Br₂ and CH₂I₂ after recrystallization from each of these solvents, was compared when subjected to these guest and guest mixtures in the vapour phase. Surprisingly, these hosts displayed entirely different behaviours under these conditions, with only the thioxanthenyl derivative possessing the ability to clathrate these guests (or guest mixtures) from the gas phase; this ability was entirely absent in the xanthenyl host. All novel complexes were subjected to single crystal diffraction analyses in order to investigate the interactions present, as well as thermal and Hirshfeld surface experiments. The host selectivity and host–guest interactions were correlated with the differences observed in the recrystallization and vapour experiments. Furthermore, data obtained for the novel complexes by employing various analytical techniques were related back to the observed selectivity order.     

Using CLEM to investigate the distribution of nano-sized antimicrobial agents within an EVOH matrix

Efficient characterization of the distribution of antimicrobial agents within a polymer matrix is of vital importance. Two antimicrobial agents, chitin nanowhiskers (ChNWs) and chitosan-based silver nanoparticles (CTSAgNPs), were produced and incorporated separately as well as combined into a poly(ethylene-co-vinyl alcohol) (EVOH) matrix by way of electrospinning. Correlative light and electron microscopy (CLEM) and energy dispersive X-ray mapping provided a holistic approach to visualize the distribution of the combinations of AgNPs and ChNWs within EVOH fibers. CLEM analysis revealed the tendency of the ChNWs to align themselves on the surface of the fibers, while the silver nanoparticles were localized inside the polymer matrix.     

Host proficiency of N,N′-bis(9-phenyl-9-thioxanthenyl)ethylenediamine for pyridine and the methylpyridine guests – a competition study

N,N′-Bis(9-phenyl-9-thioxanthenyl)ethylenediamine proved to be an extremely efficient host compound for pyridine and the isomeric methylpyridines. Furthermore, this host displayed selective behaviour during equimolar guest competitions, consistently favouring 3-methylpyridine in binary, ternary and quaternary experiments. Selectivity orders were 3-methylpyridine >> 4-methylpyridine > 2-methylpyridine, and 3-methylpyridine > pyridine > 4-methylpyridine > 2-methylpyridine, for equimolar ternary and quaternary solutions, respectively. When guest concentrations in binary competitions were varied, 3-methylpyridine remained the favoured guest, even at low 3-methylpyridine concentrations. Single crystal X-ray diffraction showed that all four complexes were isostructural (monoclinic, P2₁/n) while guests occupy discrete cavities in the crystal. Only 3-methylpyridine experiences (guest methyl)C–H???π(host) and (guest methyl)C–H???H–Ar(host) interactions, explaining the observed affinity of the host for this guest. DSC analyses provided further affirmation for the host preference: endotherm peak temperatures for the guest release processes correlated directly with the selectivity order for the three methylpyridine isomers.     

Potential facile separation strategy for mixtures of 3- and 4-methylpyridine by employing N,N′-bis(9-phenyl-9-xanthenyl)ethylenediamine as an alternative host compound

In the present work, a plausible host candidate is provided for the separation of 3-methylpyridine (3MP) from 4-methylpyridine (4MP), isomers that are extremely difficult to separate by conventional means. Host compound N,N′-bis(9-phenyl-9-xanthenyl)ethylenediamine (H2), when recrystallized from an equimolar mixture of 3MP and 4MP, contained 91.6% 3MP, a significantly improved outcome compared with the alternate host compound N,N′-bis(9-phenyl-9-thioxanthenyl)ethylenediamine (H1) which only enclathrated 70% of this isomer in the same experimental conditions. Single crystal diffraction and thermoanalytical experiments were conducted in order to investigate this preference for 3MP by considering both host?guest interactions and relative complex stabilities. Many of the guest components in 3(H2)·5(3MP)·0.268(O) experienced at least one other short contact measuring less than the sum of the van der Waals radii of the involved atoms, an observation that may explain the selectivity of H2 for this guest since this was not the case in complexes containing PYR and 4MP. Results from the thermal analyses were less informative.

     

高中化学新课程的校本化实施

高中化学新课程的校本化实施是指在遵照高中化学课程标准前提下,学校根据自身性质、特点和条件,将国家层面上规划的高中化学课程转变为适合本校学生学习需要的实践过程。高中化学新课程的校本化实施的外部条件有:国家要完善高中化学课程标准的修订;地方政府和师范院校要加大对高中化学新课程校本化实施的扶持。其内部运作可以从教学目标的校本化、教学内容的校本化、教学方式的校本化、教学评价的校本化等方面入手。     

Polyoxovanadate-Based Cyclomatrix Polyphosphazene Microspheres as Efficient Heterogeneous Catalysts for the Selective Oxidation and Desulfurization of Sulfides

The [V₆O₁₃]²⁻ cluster is successfully immobilized to the polymeric framework of cyclomatrix polyphosphazene via the facile precipitation polymerization between the phenol group symmetrically modified [V₆O₁₃]²⁻ and hexachlorocyclotriphosphazene. The structure of the as-prepared polyoxometalate-containing polyphosphazene (HCCP-V) was characterized by FT-IR, XPS, TGA, BET, as well as SEM and zeta potential. The presence of a rigid polyoxometalate cluster not only supports the porous structure of the polymeric framework but also provides an improved catalytic oxidation property. By using H₂O₂ as an oxidant, the as-prepared HCCP-V exhibited improved catalytic oxidation activity toward MPS, DBT, and CEES, which can achieve as high as 99% conversion. More importantly, the immobilization of POMs in the network of cyclomatrix polyphosphazene also provides better recyclability and stability of the heterogeneous catalyst.     

Bit-Oriented Quantum Public Key Probabilistic Encryption Schemes

Quantum public-key encryption system provides information confidentiality using quantum mechanics. In this paper, two bit-oriented public key probabilistic encryption schemes are constructed based on a new randomizing method combined with single-qubit rotation. They are strong enough to resist forward search attack and have private key secrecy. Moreover, the ciphertext expansion of the second scheme is low and the number of public key qubits used to encrypt is small under the condition that decryption error is negligible.