分子凝胶电解质的电导率研究

凝胶因子4,4'-二(硬脂酰胺基)二苯醚(BSDE)在水和非水介质(如二甲基甲酰胺、二甲基亚砜、碳酸丙烯酯等)中利用非共价键相互作用自组装成有序的三维纤维网络结构,使介质凝胶化.该凝胶被称之为分子凝胶.同样,BSDE也能使锂盐溶液凝胶化,制备一种新型分子凝胶电解质.水分子凝胶锂离子电解质的室温离子电导率达到10^-1～10^-2S·cm^-1,碳酸丙烯酯分子凝胶锂离子电解质的室温离子电导率也能达到10^-2～10^-3S·cm^-1.分子凝胶的离子电导率研究表明,锂盐在凝胶中的行为和其在溶液中的行为相似.在-35℃的低温下,分子凝胶的电导率与其溶液相比约低1～2个数量级.     

Supramolecular Chemistry in the Formation of Self‐Assembled Nanostructures from a High‐Molecular‐Weight Rod–Coil Block Copolymer

The self‐assembled nanostructures of a high‐molecular‐weight rod–coil block copolymer, poly(styrene‐block‐(2,5‐bis[4‐methoxyphenyl]oxycarbonyl)styrene) (PS‐b‐PMPCS), in p‐xylene are studied. The cylindrical micelles, long segmental cylindrical micelle associates, spherical micelles, and spherical micelle associates are observed with increased copolymer concentration. The high molecular weight of PS leads to the entanglement between PS chains from different micelles, which is the force for supramolecular interactions. Short cylindrical micelles are connected end‐to‐end via this supramolecular chemistry to form long segmental cylindrical micelle associates, analogue to the condensation polymerization process, with direction and saturation. On the other hand, spherical micelles assemble via supramolecular chemistry to form spherical micelle associates, yet without any direction due to their isotropic properties.

     

四(十二烷基)氯化铵基小分子凝胶电解质染料敏化太阳电池

采用小分子胶凝剂四（十二烷基）氯化铵胶凝3-甲氧基丙腈基液体电解质制备了凝胶电解质,并组装成准固态染料敏化太阳电池．差示扫描量热测试结果表明,凝胶电解质的溶液-凝胶转变温度（TSG）为74℃．分析了凝胶电解质中I3^-／I^-电对的表观扩散系数低于液体电解质的原因,同时结合电化学阻抗技术考察了电池内部二氧化钛多孔薄膜电极／电解质界面处的暗反应,分析了凝胶化对电池光伏性能的影响．老化实验结果表明,凝胶电池的稳定性明显优于液体电池．     

The Comparison of Electrochemical Assay and Agarose Gel Electrophoresis for the Determination of DNA Damage Induced by Kainic Acid

A possible DNA damage after interaction of kainic acid (KA) with calf thymus double stranded DNA and genomic DNA was herein determined in in vitro and in vivo conditions using; electrochemical assay and agarose gel electrophoresis. The changes in guanine signal were detected as an indicator of DNA damage in genomic DNA samples isolated from 1 or 10 mg/kg KA‐treated animals. The decreased levels of guanine signal were found as 29% and 33% by 1 and 10 mg/kg KA treatment when compared to controls, respectively. The results of gel electrophoresis confirmed DNA damage obtained in identical samples by electrochemical method.     

An Approach to Minimize Tumour Proliferation by Reducing the Formation of Components for Cell Membrane

Isoprenoids are natural compounds essential for a great number of cellular functions. One of them is farnesol (FOH), which can reduce cell proliferation, but its low solubility in aqueous solvents limits its possible clinical use as a pharmacological tool. One alternative is the use of cyclodextrins (CDs) which house hydrophobic molecules forming inclusion complexes. To assess FOH potential application in anticancer treatments, Sulfobutylated β-cyclodextrin Sodium Salt (SBE-β-CD) was selected, due to it has high solubility, approbation by the FDA, and numerous studies that ensure its safety to be administered parenterally or orally without nephrotoxicity associated. The therapeutic action of farnesol and complex were studied in different carcinoma cells, compared with a normal cell line. Farnesol showed selectivity, affecting the viability of colon and liver cancer cells more than in breast cancer cells and fibroblasts. All cells suffered apoptosis after being treated with 150 μM of free FOH, but the complex reduced their cell viability between 50 and 75%. Similar results were obtained for both types of isomers, and the addition of phosphatidylcholine reverses this effect. Finally, cell cycle analysis corroborates the action of FOH as inducer of a G0/G1 phase; when the cells were treated using the complex form, this viability was reduced, reaching 50% in the case of colon and liver, 60% in fibroblasts, and only 75% in breast cancer.     

A Mathematical Radiobiological Model (MRM) to Predict Complex DNA Damage and Cell Survival for Ionizing Particle Radiations of Varying Quality

Predicting radiobiological effects is important in different areas of basic or clinical applications using ionizing radiation (IR); for example, towards optimizing radiation protection or radiation therapy protocols. In this case, we utilized as a basis the ‘MultiScale Approach (MSA)’ model and developed an integrated mathematical radiobiological model (MRM) with several modifications and improvements. Based on this new adaptation of the MSA model, we have predicted cell-specific levels of initial complex DNA damage and cell survival for irradiation with ¹¹Β, ¹²C, ¹⁴Ν, ¹⁶Ο, ²⁰Νe, ⁴⁰Αr, ²⁸Si and ⁵⁶Fe ions by using only three input parameters (particle’s LET and two cell-specific parameters: the cross sectional area of each cell nucleus and its genome size). The model-predicted survival curves are in good agreement with the experimental ones. The particle Relative Biological Effectiveness (RBE) and Oxygen Enhancement Ratio (OER) are also calculated in a very satisfactory way. The proposed integrated MRM model (within current limitations) can be a useful tool for the assessment of radiation biological damage for ions used in hadron-beam radiation therapy or radiation protection purposes.     

Targeting Mechanisms of the DNA Damage Response (DDR) and DNA Repair by Natural Compounds to Improve cAT-Triggered Tumor Cell Death

Recently, we identified secalonic acid F (SA), 5-epi-nakijiquinone Q (NQ) and 5-epi-ilimaquinone (IQ) as natural compounds (NC) affecting mechanisms of the DNA damage response (DDR). Here, we further characterized their effects on DDR, DNA repair and cytotoxicity if used in mono- and co-treatment with conventional anticancer therapeutics (cAT) (cisplatin (Cis), doxorubicin (Doxo)) in vitro. All three NC influence the phosphorylation level of selected DDR-related factors (i.e., pCHK1, pKAP1, pP53, pRPA32) in mono- and/or co-treatment. Both SA and NQ attenuate the Cis- and Doxo-induced G2/M-phase arrest and effectively stimulate caspase-mediated apoptosis. Notably, SA impacts DNA repair as reflected by enhanced steady-state levels of Cis-(1,2-GpG)-DNA adducts and Doxo-induced DNA double-strand breaks (DSB). Moreover, SA decreased the mRNA and protein expression of the homologous recombination (HR)-related DSB repair factors RAD51 and BRCA1. Both SA and NQ promote Cis- and Doxo-induced cytotoxicity in an additive to synergistic manner (CI ≤ 1.0). Summarizing, we conclude that SA promotes cAT-driven caspase-dependent cell death by interfering with DSB repair and DDR-related checkpoint control mechanisms. Hence, SA is considered as the most promising lead compound to evaluate its therapeutic window in forthcoming pre-clinical in vivo studies.     

Characterization of Nano‐porous TiO2 Film Prepared by Sol‐gel Process and Its Application to Dye‐sensitized Solar Cell

In this paper, effects of ethylene glycol (EG) and indium tin oxide (ITO) solution on the morphology, porosity, and roughness of TiO₂ film prepared by sol‐gel process were investigated and discussed. Initially, the addition of EG were used to control the viscosity of the solution and it was found to increase the pore size of TiO₂ film. The various TiO₂ films were investigated and characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM) and then assembled to dye‐sensitized solar cell (DSSC) to measure the photoelectric conversion efficiency. The optimum efficiencies of 1.32% with J_sc and V_oc of 2.99 mA/cm² and 0.80 V, respectively, were obtained by the TiO₂ film prepared from a solution containing 20 wt% EG.     

A Combined NMR and Computational Approach to Determine the RGDechi‐hCit‐αvβ3 Integrin Recognition Mode in Isolated Cell Membranes

The critical role of integrins in tumor progression and metastasis has stimulated intense efforts to identify pharmacological agents that can modulate integrin function. In recent years, α_vβ₃ and α_vβ₅ integrin antagonists were demonstrated to be effective in blocking tumor progression. RGDechi‐hCit, a chimeric peptide containing a cyclic RGD motif linked to an echistatin C‐terminal fragment, is able to recognize selectively α_vβ₃ integrin both in vitro and in vivo. High‐resolution molecular details of the selective α_vβ₃ recognition of the peptide are certainly required, nonetheless RGDechi‐hCit internalization limited the use of classical in cell NMR experiments. To overcome such limitations, we used WM266 isolated cellular membranes to accomplish a detailed NMR interaction study that, combined with a computational analysis, provides significant structural insights into α_vβ₃ molecular recognition by RGDechi‐hCit. Remarkably, on the basis of the identified molecular determinants, we design a RGDechi‐hCit mutant that is selective for α_vβ₅ integrin.     

Unravelling the Polytoxicology of Chlorfenapyr on Non-Target HepG2 Cells: The Involvement of Mitochondria-Mediated Programmed Cell Death and DNA Damage

Chlorfenapyr (CHL) is a type of insecticide with a wide range of insecticidal activities and unique targets. The extensive use of pesticides has caused an increase in potential risks to the environment and human health. However, the potential toxicity of CHL and its mechanisms of action on humans remain unclear. Therefore, human liver cells (HepG2) were used to investigate the cytotoxic effect and mechanism of toxicity of CHL at the cellular level. The results showed that CHL induced cellular toxicity in HepG2 cells and induced mitochondrial damage associated with reactive oxygen species (ROS) accumulation and mitochondrial calcium overload, ultimately leading to apoptosis and autophagy in HepG2 cells. Typical apoptotic changes occurred, including a decline in the mitochondrial membrane potential, the promotion of Bax/Bcl-2 expression causing the release of cyt-c into the cytosol, the activation of cas-9/-3, and the cleavage of PARP. The autophagic effects included the formation of autophagic vacuoles, accumulation of Beclin-1, transformation of LC3-II, and downregulation of p62. Additionally, DNA damage and cell cycle arrest were detected in CHL-treated cells. These results show that CHL induced cytotoxicity associated with mitochondria-mediated programmed cell death (PCD) and DNA damage in HepG2 cells.     

Double Metal Ions Competitively Control the Guest‐Sensing Process: A Facile Approach to Stimuli‐Responsive Supramolecular Gels

A facile approach to the design of stimuli‐responsive supramolecular gels (SRSGs) termed double‐metal‐ion competitive coordination control is reported. By this means, the fluorescence signals and guest‐selective responsiveness of the SRSGs are controlled by the competitive coordination of two different metal ions with the gelators and the target guest. To demonstrate this approach, a gelator G2 based on multiple self‐assembly driving forces was synthesized. G2 could form Ca²⁺‐coordinated metallogel CaG with strong aggregation‐induced emission (AIE). Doping of CaG with Cu²⁺ results in AIE quenching of CaG and formation of Ca²⁺‐ and Cu²⁺‐based metallogel CaCuG. CaCuG could fluorescently detect CN^? with specific selectivity through the competitive coordination of CN^? with the Cu²⁺ and the coordination of Ca²⁺ with G2 again. This approach may open up routes to novel stimuli‐responsive supramolecular materials.     

Short Communication: A Geometrical Approach to the Structure of Noncrystalline Silica Precipitates

The structure of silica precipitates from solution may warrant examination from a viewpoint quite different from that applied to previous studies of silica glass from melt. An icosahedral model, instead of its conjugate form, a pentagonal dodecahedral type, is herewith proposed for the structure of a very basic particle 1–2 nm in diameter, which is larger than the size of a SiO₄ tetrahedron (about 0.5 nm in diameter). The model is regarded herein as a spherical, icosahedral cage composed of a fragmental sheet of polymerized SiO₄ tetrahedra oriented conforming to the surface structure of the icosahedron. The growth stage of the model "nucleus" is herein considered to comprise the formation of a concentric sheet structure that grows, however, to limited extents because of structural distortion. Beyond the size, further growth is in what may be called an essentially random array of the nucleus particles, which are found in places to be linked with each other to form varying shapes such as curved rod, ring, and concentric rings. The new perspective comes from the exploration of the basic structure of silica precipitates from solution.     

A simple algorithm to accelerate the computation of non-bonded interactions in cell-based molecular dynamics simulations

Cell lists are ubiquitous in molecular dynamics simulations--be it for the direct computation of short-range inter-atomic potentials, the short-range direct part of a long-range interaction or for the periodic construction of Verlet lists. The conventional approach to computing pairwise interactions using cell lists leads to a large number of unnecessary interparticle distance calculations. In this paper, an algorithm is presented which reduces the number of spurious distance calculations by first sorting the particles along the cell pair axis and then only interacting two particles if their distance along the axis is smaller than the cutoff distance of the interaction. This approach is shown to be more efficient than the conventional approach and similar approaches using smaller cells.     

Understanding Bacterial Bioluminescence: A Theoretical Study of the Entire Process,from Reduced Flavin to Light Emission

Bacterial bioluminescence (BL) has been successfully applied in water‐quality monitoring and in vivo imaging. The attention of researchers has been attracted for several decades, but the mechanism of bacterial BL is still largely unknown due to the complexity of the multistep reaction process. Debates mainly focus on three key questions: How is the bioluminophore produced? What is the exact chemical form of the bioluminophore? How does the protein environment affect the light emission? Using quantum mechanics (QM), combined QM and molecular mechanics (QM/MM) and molecular dynamic (MD) calculations in gas‐phase, solvent and protein environments, the entire process of bacterial BL was investigated, from flavin reduction to light emission. This investigation revealed that: 1) the chemiluminescent decomposition of flavin peroxyhemiacetal does not occur through the intramolecular chemical initiated electron exchange luminescence (CIEEL) or the “dioxirane” mechanism, as suggested in the literature. Instead, the decomposition occurs according to the charge‐transfer initiated luminescence (CTIL) mechanism for the thermolysis of dioxetanone. 2) The first excited state of 4a‐hydroxy‐4a,5‐dihydroFMN (HFOH) was affirmed to be the bioluminophore of bacterial BL. This study provides details regarding the mechanism by which bacterial BL is produced and is helpful in understanding bacterial BL in general.     

Flow Through Diffusion Cell Method: A Better Approach to Study Drug Release Behavior as Compared to Traditional Dissolution Test Method

Co‐polymeric hydrogels consisting of N‐vinyl‐2‐pyrrolidone (NVP) and acrylic acid (AAc) were synthesized and evaluated for release of a model drug, i.e., vitamin B₁₂. Release studies in simulated gastric fluid (pH 1.2) and intestinal fluid (pH 7.4), at 37°C, showed the hydrogels to be pH sensitive. An in vitro release study by ‘traditional dissolution test’ (TDT) showed that percent drug released from the hydrogel was nearly 8.6±2.1 and 83.2±4.8 in the media of pH 1.2 and 6.8, respectively. However, in order to incorporate in vivo GI conditions such as acidic pH and high water content in the stomach, low water content and the presence of a semi–solid mass in the large intestine, a new test model, called flow through diffusion cell (FTDC) was also used. The two approaches yielded almost different release profiles. The gels were characterized by thermogravimetric analysis and FTIR spectroscopy.     

A Strategy for Sample Preparation: Using Egg White Gel to Promote the Determination of Aflatoxin M1 Content in Milk Samples

The analysis of food samples is a challenging task. The high complexity of food matrices hinders the extraction and detection of analytes from them. Therefore, the correct preparation of food samples is a crucial step for their subsequent analysis, as it achieves the proper isolation and preconcentration of analytes and removes the interfering proportion of the food matrix before instrumental analysis. We aimed to develop a method that not only satisfies the requirement of detecting trace compounds in complex matrices but also achieves a “greener” approach by reducing the use of organic solvents and non-degradable materials to minimize the health hazards posed to the operators as well as pollution to the environment. In this study, we prepared egg white as a concentrated gel and used this material for the biological purification of milk samples. After the milk protein was removed by acidification and salting, the residual amount of aflatoxin M1 in milk samples was quantitatively determined by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The results showed that the novel egg white purification method possessed advantages over the immunoaffinity technique used as the reference method in extraction recovery, sensitivity, repeatability, and operability. The limit of detection (LOD) was 0.001 μg/kg. In spiked samples containing 0.01 μg/kg to 2 μg/kg of AFM1, the average recovery was 88.3–94.7%, with a precision of 6.1–11.0%. Improved repeatability was obtained by significantly reducing the operation time and resource requirements compared with the immunoaffinity technique currently used internationally. This study provides a reference for the further improvement of the relevant international standards in place for the detection of aflatoxin M1 in milk.     

Gel‐to‐Sol and Sol‐to‐Gel Transitions Utilizing the Interaction of α‐Cyclodextrin with Dodecyl Side Chains Attached to a Poly(acrylic acid) Backbone

Summary: By utilizing the interaction of α‐cyclodextrin (α‐CD) with dodecyl side chains in polymers of x mol‐% dodecyl‐modified poly(acrylic acid) (p(AA/C₁₂(x))), systems that undergo gel‐to‐sol and sol‐to‐gel transitions were successfully constructed. Rheological experiments indicated that addition of α‐CD to the hydrogel of p(AA/C₁₂(5)) caused a drastic decrease in the viscosity, while addition of oligo(α‐CD) to the solution of p(AA/C₁₂(2)) led to a remarkable increase in the viscosity.

Photographs for a gel‐to‐sol transition upon addition of α‐CD to 5.0 g · L⁻¹ p(AA/C₁₂(5)).     

A Computational Approach Applied to the Study of Potential Allosteric Inhibitors Protease NS2B/NS3 from Dengue Virus

Dengue virus (DENV) is a danger to more than 400 million people in the world, and there is no specific treatment. Thus, there is an urgent need to develop an effective method to combat this pathology. NS2B/NS3 protease is an important biological target due it being necessary for viral replication and the fact that it promotes the spread of the infection. Thus, this study aimed to design DENV NS2B/NS3pro allosteric inhibitors from a matrix compound. The search was conducted using the Swiss Similarity tool. The compounds were subjected to molecular docking calculations, molecular dynamics simulations (MD) and free energy calculations. The molecular docking results showed that two compounds, ZINC000001680989 and ZINC000001679427, were promising and performed important hydrogen interactions with the Asn152, Leu149 and Ala164 residues, showing the same interactions obtained in the literature. In the MD, the results indicated that five residues, Lys74, Leu76, Asn152, Leu149 and Ala166, contribute to the stability of the ligand at the allosteric site for all of the simulated systems. Hydrophobic, electrostatic and van der Waals interactions had significant effects on binding affinity. Physicochemical properties, lipophilicity, water solubility, pharmacokinetics, druglikeness and medicinal chemistry were evaluated for four compounds that were more promising, showed negative indices for the potential penetration of the Blood Brain Barrier and expressed high human intestinal absorption, indicating a low risk of central nervous system depression or drowsiness as the the side effects. The compound ZINC000006694490 exhibited an alert with a plausible level of toxicity for the purine base chemical moiety, indicating hepatotoxicity and chromosome damage in vivo in mouse, rat and human organisms. All of the compounds selected in this study showed a synthetic accessibility (SA) score lower than 4, suggesting the ease of new syntheses. The results corroborate with other studies in the literature, and the computational approach used here can contribute to the discovery of new and potent anti-dengue agents.     

A Practical Approach to the Development of Inkjet Printable Functional Ionogels—Bendable,Foldable, Transparent,and Conductive Electrode Materials

Ionic liquid gels, or ionogels, are semi‐conductive, flexible materials, offering a host of tunable physical properties, gaining an increasing level of scientific interest. One of the challenges of this emerging category of materials is that the structure–process–property relationships are still empirically driven. In this study, a simple, practical approach is laid out to prepare standardized libraries of these materials, for the purpose of selecting transparent, flexible conductive formulations that can be dispensed using inkjet printing. The net result of this was the optimization of a PEG‐DMA ionogel formulation exhibiting an optical transparency that was greater than 94% from near‐UV to near‐IR from a 150 µm thick films, and a resistivity of 12.4 Ω · m.