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关键词： dewetting   patterns   nanoscale   thin film   physicochemical  

摘要： Pathways to fabricate self-organized nanostructures have been identified exploiting the instabilities of ultrathin (<100 nm) polystyrene (PS) film on the polydimethylsiloxane (PDMS) substrates loaded with discrete and closely packed gold nanoparticles (AuNPs). The AuNPs were deposited on the PDMS substrates by chemical treatment, and the size and periodicity of the AuNPs were varied before coating the PS films. The study unveils that the physicochemical heterogeneity created by the AuNPs on the PDMS surface could guide the hole-formation, influence the average spacing between the holes formed at the initial dewetting stage, and affects the spacing and periodicity of the droplets formed at the end of the dewetting phase. The size and spacing of the holes and the droplets could be tuned by varying the nanoparticle loading on the PDMS substrate. Interestingly, as compared to the dewetting of PS films on the homogeneous PDMS surfaces, the AuNP guided dewetted patterns show ten-fold miniaturization, leading to the formation of the micro-holes and nanodroplets. The spacing between the droplets could also see a ten-fold reduction resulting in high-density random patterns on the PDMS substrate. Further, the use of a physicochemical substrate with varying density of physicochemical heterogeneities could impose a long-range order to the dewetted patterns to develop a gradient surface. The reported results can be of significance in the fabrication of high-density nanostructures exploiting the self-organized instabilities of thin polymers films.

关键词： Insulin  

摘要： One polysaccharide, designated as WPEP-A, was isolated from Passiflora edulis Sims peel and its hypoglycemic effects on diabetic db/db mice were evaluated. Physicochemical characterization showed that WPEP-A was composed of galactose, glucose, xylose, rhamnose, galacturonic acid and glucuronic acid with a molecular weight of 9.51 x 10(4) Da. We observed an inhibition in weight gain and blood glucose levels. Glucose tolerance and insulin tolerance improved after the administration of WPEP-A. In addition, our data showed increased antioxidant enzyme activities. Furthermore, the levels of serum insulin and triglyceride decreased with the recovery of liver damage. Meanwhile, positive changes in short chain fatty acid content were observed, and the mRNA levels of glucagon-like peptide 1 receptor, glucagon and prohormone convertase 3 were up-regulated in the intestinal tract. In summary, our results showed that WPEP-A had hypoglycemic activity and improved intestinal function in diabetic mice, which may contribute to the attenuation of the hypoglycemia effects.

关键词： Crystals   Crystal structure   Molecules   Noncovalent interactions   Diffraction  

摘要： Brain tumors are still the deadliest among all types of cancer even after decades of extensive research. Glioblastoma is the most common and aggressive form of primary malignant brain tumors. As an efficient NF-kappa B inhibitor, dimethylaminomicheliolide fumarate has shown excellent therapeutic effect for glioblastoma in clinical trials. To date, no reports about the solid forms of dimethylaminomicheliolide fumarate have been disclosed. Dimethylaminomicheliolide fumarate was thus an interesting subject for polymorphism exploration. In this work, four solid forms (Forms B, C, D, and E) were successfully obtained. The crystal structures exhibit similarity in molecular conformation and packing arrangements between Form C and Form E. The PXRD patterns and phase transition behavior suggest that Form B and Form D are likely to have similarities. Hirshfeld surfaces were generated for a better understanding of the relationships of different crystal forms. They were also characterized and evaluated by thermal analysis, polarizing microscope, and dynamic vapor sorption as well as powder properties tests. The comprehensive exploration of the solid form landscape provided essential knowledge for product development and quality control of this potential drug.

关键词： Titanium dioxide   Microwave treatment   Mechanochemical treatment   Porous structure   Electronic structure   Photocatalysis  

摘要： The effects of the microwave (MWT), hydrothermal (HTT) and mechanochemical treatments (MChT) on the structure and physicochemical properties of TiO2 precipitated from titanium sulfate and chloride were investigated. The obtained materials were characterized using the N-2 adsorption/desorption, XRD and XRF analysis, FTIR and UV-vis spectroscopy. Photo- and mechanocatalytic properties of the samples were also studied as regards the rhodamine B (RhB) degradation in the aqueous solution. All types of treatment cause significant changes in the porous structure of the samples. The XRD results showed the improvement of crystalline structure during MWT and HIT. As follows from the investigations, each way of modification results in the shift of the absorption edge towards higher wavelength values and promotes an increase in the photocatalytic activity in the process of rhodamine B degradation under visible irradiation. For the mechanocatalytic degradation, the antibate dependence of the rate constant of RhB degradation on the specific surface area of catalysts was established. (C) 2020 Elsevier B.V. All rights reserved.

关键词： kinetics   stimuli‐   sensitive polymers   theory and modeling  

摘要： Self-healing capability offers great designability on mechanical properties of double-network (DN) hydrogel. However, the thermodynamics understanding behind such physicochemical transitions and self-healing behaviors are yet to be explored properly. This study describes a renormalized Flory-Huggins lattice model for DN hydrogels, of which the physicochemical kinetics and dynamic complexity are resulted from stress-induced bond scission and macromolecule rearrangement. Based on the Flory-Huggins lattice model and Gaussian distribution theory, an extended free-energy model was formulated by the steric repulsive free-energy function. Afterwards, the function was used to identify the working mechanisms and thermodynamics in self-healing DN hydrogels with ultra-high mechanical strength. Finally, the effectiveness of model was demonstrated by applying it to predict the mechanical behaviors of DN hydrogels, where the analytical results showed good agreements with experiment data.

摘要： Phenol is one of the most toxic pollutants found in industrial waste. This work focuses on the removal of phenol using clay from the Sale region. Adsorbent was characterized by X-ray fluorescence spectroscopy, X-ray diffraction, infrared spectroscopy, and scanning electron microscopy. The chemical analysis of this clay shows that the percentage of silicon and aluminium is quite high, and the percentage of calcium and iron is relatively high, so this material is rich in muscovite, quartz, and calcite. In addition to the presence of titanium dioxide (TiO2), which can give it a property of degradation of organic compounds under ultraviolet light, the pH(PZC) zero point of our material is 7.4. The results showed that the adsorption of phenol was well fitted by the pseudo-second-order kinetic model and the Langmuir and Freundlich isotherms and that the best retention is obtained at a pH between 3 and 8.

关键词： Density   viscosity   speed of sound   refractive index   1-butyl-3-methylimidazolium tetrafluoroborate   benzonitrile   PFP theory   intermolecular interaction  

摘要： The densities, rho, speeds of sound, u, viscosity, eta and refractive indices, n(D) of 1-butyl-3-methylimidazolium tetrafluoroborate [Bmim][BF4] and Benzonitrile (BN) binary mixture, including those of pure liquids have been measured over the entire composition range at temperatures (293.15, 298.15, 303.15, 308.15, 313.15 and 318.15 K) and at atmospheric pressure. From the experimental values, excess molar volumes, , excess isentropic compressibilities, , excess speeds of sound, , excess molar isentropic compressibilities, and deviations in viscosity, Delta eta, deviations in refractive index, and deviations in molar refraction, were calculated. The partial molar volumes and partial molar isentropic compressibilities along with their excess values over whole composition range and those of the components at infinite dilution were also calculated. The resultant positive or negative deviations of these parameters have been analysed in terms of molecular interactions prevailing in these mixtures. The applicability of Prigogine-Flory-Patterson (PFP) theory in predicting the values is checked.

关键词： aliphatic amines   charge transfer   logic gates   picric acid   sensors  

摘要： Picric acid (PA) at low concentration is a serious water pollutant. Alongside, aliphatic amines (AAs) add to the queue to pollute surface water. Plenty of reports are available to sense PA with an ultralow limit of detection (LOD). However, only a handful of works are testified to detect AAs. A new fluorescent donor-acceptor compound has been synthesized with inherent intramolecular charge transfer (ICT) character that enables selective and sensitive colorimetric quantitative detection of PA and AAs with low LODs in non-aqueous as well as aqueous solutions. The synthesized compound is based on a hemicyanine skeleton containing two pyridenylmethylamino groups at the donor and a benzothiazole moiety at the acceptor ends. The detailed mechanisms and reaction dynamics are explained spectroscopically along with computational support. The fluorescence property of the detecting compound changes due to protonation of its pyridinyl centers by PA leading to quenching of fluorescence and subsequently de-protonation by AAs to revive the signal. We have further designed logic circuits from the acquired optical responses by sequential interactions.

关键词： Bamboo   Heat treatment   Surface physicochemical properties   Sorption kinetic properties   Dimensional stability  

摘要： The bamboo heat treated at 180 degrees C attracts more and more attentions for bamboo modification in industries. The effects of 180 degrees C heat treatment on surface physicochemical properties and sorption kinetic properties of bamboo were studied systematically for optimizing application. The results showed that the heat treated (HT) bamboo had much lower moisture contents both in the fast and slow process, especially at high relative humidity (RH). Meanwhile, the surface wettability was decreased and the dimensional stability was improved after heat treatment. The reduced hydrophilic OH, C = O, and C-O groups of HT bamboo caused by the degradation of polysaccharides and thermal cross-linking of lignin led to the decreased hygroscopicity. Additionally, the changed hydrogen bonding types and amorphous region of cellulose in the HT bamboo also had an effect on the water sorption behavior of cellulose. The degradation of hemicellulose and more appearance of lignin on the cell wall surface were the main reasons for the decreased water sorption behavior and improved dimensional stability of HT bamboo, which made it more suitable for applying in building and construction materials. (C) 2021 Elsevier Ltd. All rights reserved.

关键词： compressive strength   dental nano-coatings   electrospinning   RSM optimization   Ti-MOFNFs  

摘要： In this work, Ti-metal-organic framework nonofiber (MOFNF) was prepared using electrospinning method and its thermodynamic, morphological and mechanical properties was considered using related analyses, based on the ideal features of MOF and NFs using fractional factorial design. While preparing nano-coatings with some capabilities such as environmental friendly, transparent, desirable mechanical and physicochemical properties are significant, the MOFNF was used as nano-coatings with surface area close to 3204 m(2)/g, thermal stability upto 368 degrees C and 559 Pa compressive strength in dentistry. This study could be a new strategy for making dental nano-coatings with desired properties.