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Nathália Soares Simões, Hanna Leijoto de Oliveira, Ricky Cássio Santos da Silva, Leila Suleimara Teixeira, Thaís Lorenna Souza Sales, Whocely Victor de Castro, Maria José Nunes de Paiva, Cristina Sanches, Keyller Bastos Borges
In this work a hollow mesoporous structured molecularly imprinted polymer was synthetized and used as adsorbent in pipette-tip solid-phase extraction for the determination of lamivudine (3TC), zidovudine (AZT) and efavirenz (EFZ) from plasma of human immunodeficiency virus (HIV) infected patients by high-performance liquid chromatography (HPLC). All parameters that influence the recovery of the pipette tip based on hollow mesoporous molecularly imprinted polymer solid-phase extraction (PT-HM-MIP-SPE) method were systematically studied and discussed in detail...
May 17, 2018: Electrophoresis
Yingna Zhang, Hui Tang, Peiyi Wu
The thermal-induced phase transition behavior of a LCST-type poly(ionic liquid) (PIL) aqueous solution with gemini-cationic structure, poly[(1,8-octanediyl-bis(tri-n-butylphosphonium)4-styrene sulfonate)] (P[SS-P2]), was investigated in this paper. Based on the calorimetric measurements, a unique dependence of transition points on concentration was found in P[SS-P2] aqueous solution compared to its mono-cationic PIL and [SS-P2] aqueous solution. Optical microscopy showed that globular microscopic droplets were formed during the phase transition, suggesting that gemini dications and the possible dynamic ionic bonds may facilitate the liquid-liquid phase separation (LLPS) in P[SS-P2] aqueous solution...
May 16, 2018: Soft Matter
Shubo Dong, Hanyue Yang, Deju Ye
A rapid and sensitive high-performance liquid chromatography-mass spectrometry method was developed and validated to determine 4-fluoroaniline concentration in ezetimibe. Chromatographic separation was achieved on a Phenomenex Gemini-NX C18 column (150 × 4.6 mm, 3 μm) maintained at 30°C. The liquid chromatography system was operated in gradient mode with an injection volume of 20 μL at a flow rate of 1 mL/min. Mobile phase A was water and mobile phase B consisted of acetonitrile with 0.05% acetic acid. The detection was performed using a single quadrupole mass spectrometer in single ion monitoring mode by using positive ionization...
May 14, 2018: Journal of Chromatographic Science
Sonali Mondal, Animesh Pan, Animesh Patra, Rajib Kumar Mitra, Soumen Ghosh
In this contribution, we have examined a composition dependent self aggregated structural modification of a catanionic mixture of the surface active ionic liquid (IL) 1-butyl-3-methylimidazolium octyl sulphate and a cationic gemini surfactant (14-5-14) in aqueous medium. We have observed that the hydrodynamic diameter of the aggregates increases with increasing IL concentration and microscopic evidence (HRTEM, FESEM, and LCSM) shows the formation of vesicle like aggregates (Dh ≈ 200 nm) at XIL = 0.5. The steady state fluorescence anisotropy of the membrane binding probe DPH shows a micelle to vesicle transition at this composition...
May 10, 2018: Soft Matter
Webber Chan, Nicole Lynch, Peter Bampton, Jeff Chang, Alvin Chung, Timothy Florin, David J Hetzel, Simon Jakobovits, Gregory Moore, Paul Pavli, Graham Radford-Smith, Lena Thin, Brandon Baraty, Craig Haifer, Yunki Yau, Rupert W L Leong
BACKGROUND: Vedolizumab (VDZ), an α4β7 anti-integrin antibody, is efficacious in the induction and maintenance of remission in ulcerative colitis (UC) and Crohn's disease (CD). In the GEMINI long-term safety study, enrolled patients received 4-weekly VDZ. Upon completion, patients were switched to 8-weekly VDZ in Australia. The clinical success rate of treatment de-escalation for patients in remission on VDZ has not been described previously. AIM: To determine the proportion of patients who relapsed after switching from 4 to 8-weekly VDZ, the mean time to relapse, and the recapture rate when switching back to 8-weekly dosing...
April 30, 2018: European Journal of Gastroenterology & Hepatology
Wanli Kang, Yilu Zhao, Pengxiang Wang, Zhe Li, Xiaoyu Hou, Zitong Huang, Hongbin Yang
Responsive wormlike micelles (WLMs) constructed by different carboxylic acids are fascinating. However, it is unknown how the position of the carboxylic groups alters the stimuli-response of wormlike micellar systems. Herein, three pH-responsive WLMs based on Gemini-like surfactants (named o-EAPA, m-EAPA, and p-EAPA) were formed and studied through the complexation of N-erucamidopropyl-N,N-dimethylamine (UC22AMPM) and o-phthalic acid (o-PA), m-phthalic acid (m-PA), or p-phthalic acid (p-PA) at the molar ratio of 2 : 1...
April 25, 2018: Soft Matter
Aoli Wu, Panpan Sun, Na Sun, Liqiang Zheng
Low-molecular-weight supramolecular hydrogel was fabricated based on host-guest interaction between β-cyclodextrin (β-CD) and asymmetric Gemini zwitterionic liquid (ZIL) which contains azobenzene (Azo) and bis(trifluoromethanesulfonyl)imide (TFSI-). Reversible sol-gel phase transition could be triggered by light and temperature. The binding stoichiometry, main non-covalent interactions in hydrogel, photo and thermal responsive mechanisms, and inclusion complex mode were studied deeply by NMR spectroscopy, UV-vis spectroscopy, isothermal titration calorimetry (ITC) and control experiments...
April 23, 2018: Chemistry: a European Journal
Dillip Kumar Sahu, Tapas Pal, Kalyanasis Sahu
A new phase transfer strategy has been introduced to convert aqueous phase protein-protected nanomaterials into fluorescent nanoclusters in the reverse micellar environment using bovine serum albumin (BSA)-protected silver nanoclusters (AgNCs) and nanoparticles (AgNPs) as an example. Thanks to the basic pH employed in the fabrication of protein-protected nanoclusters that induces negative charge of the protein capping and facilitates the transfer process of the nanomaterials from aqueous phase to a cationic gemini surfactant (16-2-16)/hexane/hexanol/water reverse micelle (RM) phase...
April 23, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Kai Zhang, Shaojuan Luo, Zewei Liu, Chao Li, Ke Zheng, Xin Yan, Ying Wu, Hongxia Xi
Amphiphilic surfactants are widely used as templates to synthesize hierarchically structured zeolites due to their multiple functions; however, piloting such new dual-functional templates is limited by its nature of time-consuming and high cost. Herein, a simple organic molecule, without a long hydrophobic alkyl chain, was tailored from a gemini-type, poly-quaternary ammonium surfactant and effectively used as a dual-porogenic template to synthesize hierarchical MTW zeolite. Upon a range of synthesis parameters optimization, our detailed characterizations suggested that the hierarchical MTW zeolite would completely crystallize within 36 hours from the surface to inside of quasi - spherical particles through in situ consumption of amorphous silicon and aluminum species, much faster than most of the hierarchical MTW zeolite generated by conventional methods...
April 12, 2018: Chemistry: a European Journal
Yaxun Fan, Yilin Wang
Oligomeric surfactant is comprised of three or more amphiphilic moieties that are covalently connected by spacer groups at the level of headgroups. It provides a possible route to bridge the gap from conventional single-chain surfactants and gemini surfactants to polymeric surfactants, and leads to many profound improvements in the performance of surfactants in aqueous solution and at the air/water and water/solid interfaces. Generally oligomeric surfactants can be classified as linear, ring-like and star-shaped according to the structures of their spacer groups, and their aggregation behavior strongly depends on the resultant topological structures...
April 4, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Lin Wang, Xuefeng Shi, Jinben Wang
In this study, a novel supramolecular hydrogel, abbreviated as AGC16/NTS, was designed and constructed by the molecular self-assembly of a cationic gemini surfactant, 1,3-bis(N,N-dimethyl-N-cetylammonium)-2-propylacrylatedibromide (AGC16), and an anionic aromatic gelator, trisodium 1,3,6-naphthalenetrisulfonate (NTS). The AGC16/NTS hydrogel was able to form in a mass ratio range of AGC16 and NTS from 20 : 1 to 10 : 1. It was interestingly found that AGC16/NTS exhibited two phase transitions (gel-to-gel and gel-to-sol) observed by visual and rheological measurements during the heating process, which is rarely reported in the previous literature reports of hydrogels prepared using low molecular weight gelators...
April 3, 2018: Soft Matter
Mahdiyeh Poorsargol, Beheshteh Sohrabi, Maryam Dehestani
Understanding the mechanism of adsorption and self-assembly of surfactants on graphene is highly important to perform better optimization of graphene dispersion process. Due to Gemini surfactants special structure, they have a high charge capacity, high hydrophobicity and unique self-assembly properties compared to single-chain surfactants. Therefore, the Gemini surfactants with their little concentrations are expected to disperse and stabilize graphene nanosheets in aqueous solutions more effectively. We conducted all-atomic molecular dynamics simulations to study adsorption and self-assembly of the single-chain cationic surfactant dodecyltrimethylammonium bromide (C12TAB) and its same family Gemini surfactant dimethylene-α,β-bis(dodecyldimethylammonium bromide) ([12-2-12]Br2) on graphene nanosheets in aqueous solution...
March 26, 2018: Journal of Physical Chemistry. A
Luc Brunsveld, Jurgen Schill, Sam van Dun, Maarten Pouderoijen, Henk Janssen, Lech-Gustav Milroy, Albert Schenning
Interest in bay-substituted perylene-3,4:9,10-tetracarboxylic diimides (PDIs) for solution-based applications is growing due to their improved solubility and altered optical and electronic properties with respect to unsubstituted PDIs. Synthetic routes to 1, 12 bay-substituted PDIs have been very demanding due to issues with steric hindrance and poor regioselectivity. Here we report a simple one-step regioselective and high yielding synthesis of a 1,12-dihydroxylated PDI derivative that can subsequently be alkylated in a straightforward fashion to produce nonplanar 1,12-dialkoxy PDIs...
March 22, 2018: Chemistry: a European Journal
Tadashi Sugahara, Yuichiro Takamatsu, Avinash Bhadani, Masaaki Akamatsu, Kenichi Sakai, Masahiko Abe, Hideki Sakai
In this study, we synthesize a novel oleic acid-based gemini surfactant with carboxylate headgroups, and study the effect of stereochemistry (anti- vs. syn-) on self-aggregation properties in water. We investigate these properties using phase diagrams, static surface tension, and one-dimensional and two-dimensional nuclear magnetic resonance (NMR) measurements. We find that a phase transition from a hexagonal liquid crystal (H1) phase to a lamellar liquid crystal (Lα) phase occurs at a lower surfactant concentration in the syn form, when compared with the anti form...
March 16, 2018: Physical Chemistry Chemical Physics: PCCP
Anna Koziróg, Bogumił Brycki, Katarzyna Pielech-Przybylska
This study investigates the biological activity of two cationic gemini surfactants, hexamethylene-1,6-bis-( N , N -dimethyl- N -dodecylammonium bromide) C6 and pentamethylene-1,5-bis-( N , N -dimethyl- N -dodecyla,.mmonium bromide) C5, and their two neutral analogs, hexamethylene-1,6-bis-( N -methyl- N -dodecylamine) (A6) and pentamethylene-1,5-bis-( N -methyl- N -dodecylamine) (A5). Experiments were performed with Aspergillus brasiliensis , which is used in the standard tests for biocides. The minimal inhibitory concentration (MIC) values for conidia and mycelium were determined using the dilution method...
March 15, 2018: International Journal of Molecular Sciences
Min Yang, Zhonghua Dong, Xiaoyan Jiang, Zhongxi Zhao, Jianqiang Zhang, Xinke Cao, Daizhou Zhang
In this work, a rapid, simple, sensitive and specific LC-MS/MS method was developed and validated for the quantification of S-Allylmercaptocysteine (SAMC) in plasma. After a simple sample procedure by one step protein precipitation with acetontrile, the samples were separated on Gemini-NX C18 column (2.1 mm i.d. 150 mm, 3 μm, Phenomenex). The mobile phase was composed of water-acetonitrile (20:80, v/v) at an isocratic flow rate of 0.3 mL/min. The developed method was validated based on the International Conference on Harmonization (ICH) guidelines...
March 7, 2018: Journal of Chromatographic Science
Romain Madelaine, James H Notwell, Gemini Skariah, Caroline Halluin, Charles C Chen, Gill Bejerano, Philippe Mourrain
Thousands of human disease-associated single nucleotide polymorphisms (SNPs) lie in the non-coding genome, but only a handful have been demonstrated to affect gene expression and human biology. We computationally identified risk-associated SNPs in deeply conserved non-exonic elements (CNEs) potentially contributing to 45 human diseases. We further demonstrated that human CNE1/rs17421627 associated with retinal vasculature defects showed transcriptional activity in the zebrafish retina, while introducing the risk-associated allele completely abolished CNE1 enhancer activity...
March 6, 2018: Nucleic Acids Research
Apensu Dey, Victoria Sandre, Daniel Gerrard Marangoni, Soumen Ghosh
Ibuprofen (IBF), 2-(4-isobutylphenyl) propionic acid, is a surface-active, common nonsteroidal anti-inflammatory drug (NSAID), and it possesses a high critical micelle concentration (cmc) compared to that of conventional surfactants. The interactions of this common NSAID with an anionic surfactant, sodium octyl sulfosuccinate, were studied by tensiometric, fluorimetric, and calorimetric measurements to investigate this system as a possible model drug-delivery system for an NSAID like IBF, particularly in a high-dose regime for IBF...
April 12, 2018: Journal of Physical Chemistry. B
Jing Sun, Chong Qiu, Yiping Diao, Wei Wei, Hongwei Jin, Yi Zheng, Jiancheng Wang, Lihe Zhang, Zhenjun Yang
Small interfering RNA (siRNA) has been continuously explored for clinical applications. However, neither nanocarriers nor conjugates have been able to remove the obstacles. In this study, we employed a combined nanochemistry strategy to optimize its delivery dilemma, where different interactions and assembly modes were cooperatively introduced into the forming process of siRNA/lipids nanoplexes. In the nanoplexes, the 3',3″-bis-peptide-siRNA conjugate (pp-siRNA) and gemini-like cationic lipids (CLDs) were employed as dual regulators to improve their bio-behavior...
March 2, 2018: Molecular Therapy. Nucleic Acids
Bappa Maiti, Mohini Kamra, Anjali A Karande, Santanu Bhattacharya
Herein, five new α-tocopheryl cationic gemini lipids with hydroxyethyl bearing headgroups (THnS, n = 4, 5, 6, 8, 12) have been synthesized for efficient plasmid DNA (pDNA) delivery into cancer cells. Among these gemini lipid formulations, the lipid with an octamethylene [-(CH2 )8 ] spacer (TH8S) showed the highest transfection efficiency (TE) that was comparable to that of the commercial standard lipofectamine 2000 (L2K) in terms of luciferase expression in HepG2 (liver hepatocellular carcinoma) cells. The addition of the helper lipid DOPE (1,2-dioleoyl phosphatidyl ethanolamine) with cationic lipids in mixed liposomes further enhanced the TE and the optimized molar ratio was 2 : 1 (DOPE : cationic lipid)...
March 14, 2018: Organic & Biomolecular Chemistry
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