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Novel switchable gemini imidazolium surfactants with different carbon atoms in hydrophobic group were successfully synthesized by condensation of fatty acid with triethylene tetramine, then the intermediates were reacted with CO2 to give the imidazolinium bicarbonates. The structures of intermediates and products were identified by IR and 1H-NMR spectra. As the results show, the structures of the products obtained correspond to the target compounds designed. By surface tension measurements, these Gemini surfactants have excellent surface activity with low cmc and surface tension. The conductivity and surface tension cycles show that these surfactants could be switched from imidazoline (neutral form) to imidazolium bicarbonate (charged form ) reversibly and repeatedly. [ABSTRACT FROM AUTHOR]

In this paper, an improved method for the preparation of erucyl dimethyl amidopropyl betaine (EDAB) was provided. The syn-thesis conditions were investigated. N,N-dimethyl-N'-erucyl-l,3-propylenediamine was synthesized by the reaction of erucic acid with N,N-dimethyl-l,3-propylenediamine at 170°C for 7 h, and then the intermediate was reacted with sodium chloroacetate in the mixture of methanol and water (3:7 v/v) at 60 °C. The product was obtained after 6 h. The compounds were con-firmed by IR and 'H-NMR. The properties of EDAB acid solution were also studied. The results indicated that viscosity of acid so-lution increased with decreasing hydrochloric acid concentration and was mainly controlled by surfactant concentration and tem-perature. The viscosity of an acid solution was maximum when the concentration of hydrochloric acid was at 15 wt%. [ABSTRACT FROM AUTHOR]

Epidermal growth factor receptor (EGFR) is frequently overexpressed in multiple malignancies. Icotinib (IH), a new EGFR tyrosine kinase inhibitor, enhances radiosensitivity in various types of cancer, but its effect on nasopharyngeal carcinoma (NPC) remains unclear. Total 115 NPC tissue sections and 30 nasopharyngitis tissue sections were enrolled. The correlation of EGFR expression and clinicopathologic features of NPC was analyzed. Survival analysis was calculated by using univariate and multivariate regression analysis. A radioresistant NPC cell line, CNE-2R, was established with a gradient irradiation schedule. Cell viability, colony formation and EGFR expression of CNE-2/2R cells were examined. Significant higher expression of EGFR was observed in NPC tissues than chronic nasopharyngitis lesions. EGFR expression was significantly correlated with both tumor stage (P < 0.001) and tumor-node-metastasis stage of NPC (P = 0.006). EGFR expression was an independent prognostic factor of disease-free survival (P = 0.047) and the overall survival of NPC (P = 0.016). Cell viability was higher in CNE-2R than CNE-2 on days 1, 2, 4, and 6 after radiation of 4 Gy. The colony number of CNE-2R was significantly higher than that of CNE-2 (P < 0.05), while IH enhanced the radiosensitizing effect of CNE-2R with lower survival fraction (P < 0.05). EGFR mRNA and protein expression levels were significantly higher in CNE-2R cells compared to CNE-2 cells, but significantly decreased after IH treatment (all P < 0.05). In conclusion, high EGFR expression is a poor prognostic factor for NPC patients. IH enhances the radiosensitivity of CNE-2R cells and reduce EGFR expression. [ABSTRACT FROM AUTHOR]

Polyacrylamide and its derivatives are widely used in oilfields due to their efficient viscosity building and drag-reducing properties. At present, the commonly used products of polyacrylamide include two types: polymer powder and polymer emulsions. However, the low dissolution rate of powdered products and the instability of polymer emulsions limit their application. Here, we constructed a pH-sensitive inverse polymer emulsion of poly(acrylamide-co-acrylic acid-co-2-acrylamide-2-methylpropyl sulfonic acid), showing a phase separation and phase inversion from W/O to O/W at pH o 6 and pH 4 8 due to a pHswitchable surfactant N,N-dimethylcyclohexylamine/Oleic acid complex (DM-OA). The demulsification or phase inversion of the W/O polymer emulsion can release the polymer that was originally in the aqueous phase, and the released polymer can quickly dissolve in water to perform its function of viscosity building and friction reduction. Therefore, this pH-sensitive modified-polyacrylamide polymer emulsion shows a fast dissolution rate with a dissolution time of about 1 min and a long storage stability. The utilization of stimuli-responsive surfactants to construct pH-responsive water-soluble polymer W/O emulsions provides a new approach to the preparation of water-soluble polymer emulsion additives that can be quickly dissolved and stored for long periods of time in water-treatment, papermaking and oil recovery fields. [ABSTRACT FROM AUTHOR]

Active waveband selective switches for the telecommunication wavebands are fabricated and demonstrated. This type of active waveband selective switch is composed of a guided-mode resonance filter, a twisted nematic liquid crystal (TNLC) layer, and a linear polariser. In voltage-off status, a fabricated active waveband selective switch with grating period of 893.86 nm exhibits high resonance peak with wavelength around 1311.2 nm. In voltage-on status, this switch exhibits a high resonance peak with wavelength around 1551.3 nm. The measured reflection peaks of another active waveband selective switch with grating period of 872.84 nm are located at 1309.1 and 1549.4 nm in voltage-on status and voltage-off status, respectively. Thus, light waveband can be tuned between O-band and C-band by electrically driving the TN-LC layer of this type of active waveband selective switch in real time. [ABSTRACT FROM AUTHOR]

Switchable hydrophilic solvent (SHS) has been developed as a green extractant for separate lipophilic substances. This article reported an efficient method to extract and recovery diesel in oil-based drill cuttings by using SHS. 1 H NMR spectroscopy and pH measurement provided the possibility of SHS can be applied to the recovery of diesel. The screenings of SHS were carried out by CO 2 absorption experiments and the solubility of SHS and diesel, which depended on the absorption rate and the solubility parameter model, respectively. The recovery process analyzed the reclaim performance of diesel and DMCHA. The dynamic analysis indicated that the process of DMCHA recovery was consistent with the first-order kinetic, and proved the conclusion of the influence of temperature and aeration rate on DMCHA recovery. Ultimately, the rate constant was used to obtain the DMCHA recovery activation energy of 30.37 kJ mol −1 , which provided a reference for the study of low energy consumption. All above studies provided guidance for the design of recycling diesel oil in oil-based drill cuttings by SHS, and therefore, it can achieve the safety and environmental protection of oil-based drill cuttings. [ABSTRACT FROM AUTHOR]

Microforming using a small machine (or so-called desktop machine) is an alternative new approach to those using full-size heavy equipment for manufacturing microparts. Microparts are commonly defined as parts or structures with at least two dimensions in the submillimeter range, which are used extensively in electronics and micromechanical products. However; when scaling down a conventional forming process to microscale, the influence of the so-called size effect needs to be considered. The individual micro structure (size, shape, and orientation of grains) and the interfacial conditions show a significant effect on the process characteristics. In this paper; the process of extrusion is investigated to establish it as a viable process for microforming. A forming assembly is fabricated and used in conjunction with a loading substage to extrude micropins with a final diameter of 1 mm. The effect of grain size is investigated by using workpieces heat treated to produce grain sizes varying from 32 µm up to 211 µm. Two extrusion dies with different roughness are used to study the effect of surface finish. While experiments lead to interesting questions and new discoveries, theoretical or numerical solutions are necessary tools for process optimization. Here, knowing the limits of the current widely used numerical simulation tools [i.e., the Finite Element Method (FEM)], a new method, the Reproducing Kernel Element Method (RKEM), has recently been developed to address the limitations of the FEM (for example, remeshing issue), while maintaining FEM's advantages, e.g., the polynomial reproducing property and function interpolation property. The new RKEM method is used to simulate the microextrusion problem. Its results are compared with that obtained from the FEM and the experiment result Satisfactory results were obtained. Future directions on the experimental and simulation work are addressed. [ABSTRACT FROM AUTHOR]