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https://www.readbyqxmd.com/read/28929563/morphology-dependent-cell-imaging-by-a-self-assembled-diacetylene-peptide-amphiphile
#1
Carsten Schmuck, Hao Jiang, Xiao-Yu Hu, Stefanie Schlesiger, Mao Li, Elio Zellermann, Shirley Knauer
Herein, a novel cationic peptide gemini amphiphile containing diacetylene motifs (DA2P) is presented which self-assembles into novel tadpole- and bola-shaped nanostructures at low concentration and nanofibers at higher concentration, respectively. Interestingly, the DA2P assemblies can be polymerized to a fluorescent red phase but only during incubation with HeLa cells, most likely owing to the reorganization of the diacetylene chains of DA2P upon interaction with the cell membrane. The red-fluorescent polymerized DA2P assemblies can serve as a novel cell imaging probe...
September 20, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28905622/proton-diffusion-through-bilayer-pores
#2
Jesse Gatten McDaniel, Arun Yethiraj
The transport of protons through channels in complex environments is important in biology and materials science. In this work, we use multistate empirical valence bond simulations to study proton transport within a well-defined bilayer pore in a lamellar Lβ phase lyotropic liquid crystal (LLC). The LLC is formed from the self-assembly of dicarboxylate gemini surfactants in water, and a bilayer-spanning pore of ∼3-5 A radius results from the uneven partitioning of surfactants between the two leaflets of the lamella...
September 14, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28893789/gemini-cationic-amphiphiles-control-biofilm-formation-by-bacterial-vaginosis-pathogens
#3
Ammar Algburi, Yingyue Zhang, Richard Weeks, Nicole Comito, Saskia Zehm, Juanita Pinto, Kathryn E Uhrich, Michael L Chikindas
Antibiotic resistance and recurrence of bacterial vaginosis (BV), a polymicrobial infection, justify the need for novel antimicrobials to counteract microbial resistance to conventional antibiotics. Previously, two series of cationic amphiphiles (CAms), which self-assemble into supramolecular nanostructures with membrane-lytic properties, were designed with hydrophilic head groups and non-polar domains. The combination of CAms with commonly prescribed antibiotics is suggested as a promising strategy for targeting microorganisms that are resistant to conventional antibiotics...
September 11, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28873306/mixing-behavior-in-binary-anionic-gemini-surfactant-perfluorinated-fatty-acid-langmuir-monolayers
#4
Jeveria Rehman, David Sowah-Kuma, Amy L Stevens, Wei Bu, Matthew F Paige
The miscibility and film structure of mixed Langmuir monolayer films comprised of an anionic gemini N, N, N', N'dialkyl-N,N'-diacetate ethylenediamine surfactant (Ace(12)-2-Ace(12)) with perfluorotetradecanoic acid (C13F27COOH; PF) has been investigated using a variety of thermodynamic and structural characterization methods. The two film components were found to be miscible in monolayers at the air-water interface over a range of compositions and at all but the lowest surface pressures, with attractive interactions occurring between the two components...
September 5, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28866183/application-of-gemini-quaternary-ammonium-with-ester-groups-in-cationic-p-st-co-ba-nanolatex-and-study-on-its-antibacterial-properties
#5
Yue Xu, Hang Gao, Yan Shen, Shigan Chai, Jinzhi Zhang, Qichao Zou
Novel Gemini quaternary ammonium salts (GQASs) with ester groups were synthesized. Cationic poly(styrene-co-butyl acrylate) (P(St-co-BA)) nanolatex was synthesized in the presence of GQASs as emulsifier. The structures of GQASs were characterized with Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy; the property of P(St-co-BA) nanolatex was characterized with dynamic light scattering. The results indicated that GQASs and P(St-co-BA) nanolatex with GQASs were successfully synthesized...
November 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28865686/use-of-the-hyphenated-lc-ms-ms-technique-and-nmr-ir-spectroscopy-for-the-identification-of-exemestane-stress-degradation-products-during-the-drug-development
#6
Elżbieta U Stolarczyk, Anna Rosa, Marek Kubiszewski, Joanna Zagrodzka, Marcin Cybulski, Łukasz Kaczmarek
Exemestane (6-Methyleneandrosta-1,4-diene-3,17-dione) active pharmaceutical ingredient (EE-3) was subjected to thermal, photolytic, oxidative, acidic and base stress conditions prescribed by the ICH (International Conference on Harmonization) guideline Q1A(R2). EE-3 was found to degrade in base, acidic and oxidative conditions. Eleven new degradation products of EE-3 were characterized by the LC-MS/MS technique. One of these impurities was isolated and identified by the LC-MS/MS, NMR and IR techniques. The LC-MS/MS studies were carried out to establish fragmentation pathways of EE-3 and its new impurity...
September 1, 2017: European Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28863648/low-profile-self-sealing-sample-transfer-flexure-box
#7
Kevin Simon, Lukas Porz, Tushar Swamy, Yet-Ming Chiang, Alexander Slocum
A flexural bearing mechanism has enabled the development of a self-sealing box for protecting air sensitive samples during transfer between glove boxes, micro-machining equipment, and microscopy equipment. The simplicity and self-actuating feature of this design makes it applicable to many devices that operate under vacuum conditions. The models used to design the flexural mechanism are presented in detail. The device has been tested in a Zeiss Merlin GEMINI II scanning electron microscope with Li3PS4 samples, showing effective isolation from air and corrosion prevention...
August 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28831105/emotional-over-and-under-eating-in-early-childhood-are-learned-not-inherited
#8
Moritz Herle, Alison Fildes, Silje Steinsbekk, Fruhling Rijsdijk, Clare H Llewellyn
Emotional overeating (EOE) has been associated with increased obesity risk, while emotional undereating (EUE) may be protective. Interestingly, EOE and EUE tend to correlate positively, but it is unclear whether they reflect different aspects of the same underlying trait, or are distinct behaviours with different aetiologies. Data were from 2054 five-year-old children from the Gemini twin birth cohort, including parental ratings of child EOE and EUE using the Child Eating Behaviour Questionnaire. Genetic and environmental influences on variation and covariation in EUE and EOE were established using a bivariate Twin Model...
August 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28825837/self-assembly-in-aqueous-oppositely-charged-gemini-surfactants-a-correlation-between-morphology-and-solubilization-efficacy
#9
Sneha Singh, Arti Bhadoria, Kushan Parikh, Sanjay Kumar Yadav, Sugam Kumar, V K Aswal, Sanjeev Kumar
Micellization behavior of oppositely charged gemini surfactants (anionic surfactant; phosphoric acid, P,P'-1,4-butanedieyl, P,P'-didodecylester, disodium salt (12-4-12A), and cationic surfactant; butanediyl-1,4, bis (N,N-hexadecyl ammonium) dibromide (16-4-16) or (D-isosorbate-1,4-diyl bis(N,N-dimethyl-N-hexadecylammonium acetoxy) dichloride (16-Isb-16)) has been studied (individually or of a gemini mixture) by conductivity and surface tension measurements. Critical micelle concentration (CMC) data show both synergistic (for 12-4-12A + 16-Isb-16) and antagonistic (for 12-4-12A + 16-4-16) interactions between the two components...
September 8, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28813666/microrna-9-couples-brain-neurogenesis-and-angiogenesis
#10
Romain Madelaine, Steven A Sloan, Nina Huber, James H Notwell, Louis C Leung, Gemini Skariah, Caroline Halluin, Sergiu P Paşca, Gill Bejerano, Mark A Krasnow, Ben A Barres, Philippe Mourrain
In the developing brain, neurons expressing VEGF-A and blood vessels grow in close apposition, but many of the molecular pathways regulating neuronal VEGF-A and neurovascular system development remain to be deciphered. Here, we show that miR-9 links neurogenesis and angiogenesis through the formation of neurons expressing VEGF-A. We found that miR-9 directly targets the transcription factors TLX and ONECUTs to regulate VEGF-A expression. miR-9 inhibition leads to increased TLX and ONECUT expression, resulting in VEGF-A overexpression...
August 15, 2017: Cell Reports
https://www.readbyqxmd.com/read/28809098/interfacially-engineered-pyridinium-pseudogemini-surfactants-as-versatile-and-efficient-supramolecular-delivery-systems-for-dna-sirna-and-mrna
#11
Uttam Satyal, Bogdan Draghici, Lisa L Dragic, Qiangnan Zhang, Kyle W Norris, Muniswamy Madesh, Eugen Brailoiu, Marc A Ilies
This article presents the synthesis, self-assembly, and biological activity as transfection agents for pDNA, siRNA, and mRNA of novel pyridinium pseudogemini surfactants, interfacially engineered from the most efficient gemini surfactants and lipids generated in our amphiphile research program. Formulation of novel amphiphiles in water revealed supramolecular properties very similar to those of gemini surfactants, despite their lipidlike charge/mass ratio. This dual character was found also to enhance endosomal escape and significantly increase the transfection efficiency...
August 25, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28800974/advances-in-the-synthesis-molecular-architectures-and-potential-applications-of-gemini-surfactants
#12
REVIEW
Renu Sharma, Ajar Kamal, Maryam Abdinejad, Rakesh Kumar Mahajan, Heinz-Bernhard Kraatz
Gemini surfactants have been the subject of intensive scrutiny by virtue of their unique combination of physical and chemical properties and being used in ordinary household objects to multifarious industrial processes. In this review, we summarize the recent developments of gemini surfactants, highlighting the classification of gemini surfactants based on the variation in headgroup polarity, flexibility/rigidity of spacer, hydrophobic alkyl chain and counterion along with potential applications of gemini surfactants, depicting the truly remarkable journey of gemini surfactants that has just come of age...
July 29, 2017: Advances in Colloid and Interface Science
https://www.readbyqxmd.com/read/28763772/ph-responsive-chitosan-nanoparticles-from-a-novel-twin-chain-anionic-amphiphile-for-controlled-and-targeted-delivery-of-vancomycin
#13
Rahul S Kalhapure, Mahantesh Jadhav, Sanjeev Rambharose, Chunderika Mocktar, Sanil Singh, Jwala Renukuntla, Thirumala Govender
The design and synthesis of novel pH-responsive nanoantibiotics is an emerging research area to address the antibiotic resistance crisis. The purpose of this study was therefore to synthesize a new anionic gemini surfactant (AGS) that could result in the formulation of pH-responsive chitosan nanoparticles (CSNPs) to treat methicillin-resistant Staphylococcus aureus (MRSA) infections. The coupling of oleic acid with 2,2-dimethyl-5,5-bis(hydroxymethyl)-1,3-dioxane and subsequent deprotection followed by a reaction with succinic anhydride and sodium bicarbonate yielded AGS...
July 24, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28759721/microchip-circulation-drastically-accelerates-amyloid-aggregation-of-1-42-%C3%AE-amyloid-peptide-from-felis-catus
#14
Witold Gospodarczyk, Maciej Kozak
Amyloid aggregation process of amyloid beta 1-42 peptide is responsible for Alzheimer disease, concerning millions of elderly people worldwide. Although there has a great deal of attention made to tackle this disease, there still has not been found any medicine for this fatal disorder. In order to come against this challenge, it is vital to thoroughly understand the molecular mechanism underlying peptide amyloid aggregation process, as well as seek for substances which could hamper this aggregation. In order to shed light on mechanisms leading to amyloidogenesis, we employed a microfluidic system to determine the possible influence of in vivo-like flow in microchip channel itself on peptide amyloidogenesis...
July 31, 2017: ACS Chemical Neuroscience
https://www.readbyqxmd.com/read/28755557/amphiphilic-gemini-pyridinium-mediated-incorporation-of-zn-ii-meso-tetrakis-4-carboxyphenyl-porphyrin-into-water-soluble-gold-nanoparticles-for-photodynamic-therapy
#15
María E Alea-Reyes, Jorge Soriano, Inma Mora-Espí, Mafalda Rodrigues, David A Russell, Leonardo Barrios, Lluïsa Pérez-García
Zn-containing porphyrins are intensely investigated for their ability to form reactive oxygen species and thereby being potent photosensitizers for use in photodynamic therapy (PDT). Some of the drawbacks of the PDT approach, such as unspecific distribution, could be addressed by means of photosensitizer drug delivery systems. In this work, we synthesize and characterize new water-soluble gold nanoparticles (GNP) stabilized by a mixture of a polyethyleneglycol-containing thiol (to improve water solubility) and a new amphiphilic gemini-type pyridinium salt, which also acts as promotor of the incorporation of the anionic photosensitizer Na-ZnTCPP into the GNP...
July 18, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28737786/fluorescence-emission-originated-from-the-h-aggregated-cyanine-dye-with-chiral-gemini-surfactant-assemblies-having-a-narrow-absorption-band-and-a-remarkably-large-stokes-shift
#16
Naoya Ryu, Yutaka Okazaki, Emilie Pouget, Makoto Takafuji, Shoji Nagaoka, Hirotaka Ihara, Reiko Oda
We demonstrate that the fluorescence emission that originated from a cyanine dye forming H-aggregates with a narrow absorption band and a remarkably large Stokes shift can be induced by symmetry breaking. The H-aggregate formation was successfully induced using chirally assembled cationic gemini surfactants with enantiomeric tartrate counterions as templates in water.
July 24, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28731344/correction-to-rational-design-and-synthesis-of-carboxylate-gemini-surfactants-with-an-excellent-aggregate-behavior-for-nano-la2o3-morphology-controllable-preparation
#17
Xueming Liao, Zhinong Gao, Yan Xia, Fei Niu, Wenzhong Zhai
No abstract text is available yet for this article.
July 21, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28722057/janus-particles-self-assembled-from-a-small-organic-atypical-asymmetric-gemini-surfactant
#18
Lei Tang, Jun Yang, Qinqin Yin, Linghui Yang, Deying Gong, Feng Qin, Junyang Liu, Qin Fan, Jiahong Li, Wenling Zhao, Weiyi Zhang, Jiyu Wang, Tao Zhu, Wensheng Zhang, Jin Liu
A series of atypical asymmetric gemini surfactants with an amphiphilic carbonate group (-O-CO-O-) have been prepared. Some of these compounds could self-assemble in water into gourd-shaped Janus particles (JPs). Initial results suggested that the formation of JPs was highly likely to be related to their atypical gemini surfactant structure. To our knowledge, this is the first report on JPs that are self-assembled from a single kind of small organic molecule. We believe that our results will be utilized in many fields...
July 19, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28715030/a-chiral-binol-based-gemini-amphiphilic-gelator-and-its-specific-discrimination-of-native-arginine-by-gelation-in-water
#19
Lihua Jia, Jianxin Yin, Xiangfeng Guo, Guangzhou Cao, Xuhua Tian, Bo Zhu, Lin Pu
A novel axially chiral cationic Gemini amphiphile gelator (S1) derived from (S)-BINOL has been synthesized and characterized by (1)H NMR, (13)C NMR, ESI-MS and FT-IR analyses. The critical micelle concentration (CMC) of S1 was determined to be 0.21 mM in water at room temperature. A transparent hydrogel with S1 at 43 mM was obtained at room temperature and characterized using various methods including SEM, CD, fluorescence, (1)H NMR, FT-IR, and XRD. The results indicate that the hydrophobic effect of long alkyl chains, π-π stacking of naphthalene rings, and intermolecular hydrogen-bonding of the amide groups of S1 should be responsible for the hydrogel formation...
August 16, 2017: Soft Matter
https://www.readbyqxmd.com/read/28714228/polyladderane-constructed-from-a-gemini-monomer-through-photoreaction
#20
Zhihan Wang, Benjamin Miller, Jonathan Butz, Katelyn Randazzo, Zijun D Wang, Qianli R Chu
Polyladderane, the first polymer to contain the ladderane functional group, was synthesized from a gemini monomer through photoreaction in the solid state. The modular design of the gemini monomers used to create polyladderane allowed specific structural modification, resulting in the formation of two distinct polymer products. Monomers were synthesized by connecting two photoreactive units, either sorbic acids (monomer I) or 2-furanacrylic acids (monomer II), with a 1,4-butanediol linker. Single-crystal X-ray diffraction analysis of the monomers confirmed that they packed in the desired head-to-tail orientation and within a viable distance for photoreaction by electronically complementary interaction...
July 17, 2017: Angewandte Chemie
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