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https://www.readbyqxmd.com/read/28549295/structural-characterization-of-astaxanthin-aggregates-as-revealed-by-analysis-and-simulation-of-optical-spectra
#1
Liping Lu, Taoping Hu, Zhigang Xu
Carotenoids can self-assemble in hydrated polar solvents to form J- or H-type aggregates, inducing dramatic changes in photophysical properties. Here, we measured absorption and emission spectra of astaxanthin in ethanol-water solution using ultraviolet-visible and fluorescence spectrometers. Two types of aggregates were distinguished in mixed solution at different water contents by absorption spectra. After addition of water, all probed samples immediately formed H-aggregates with maximum blue shift of 31nm...
May 15, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28548628/endothelial-progenitor-cells-for-the-vascularization-of-engineered-tissues
#2
Erica Brown Peters
Self-assembled microvasculature from cocultures of endothelial cells and stromal cells have significantly advanced efforts to vascularize engineered tissues by enhancing perfusion rates <i>in vivo</i> and producing investigative platforms for microvascular morphogenesis <i>in vitro</i>. However, in order to clinically translate prevascularized constructs, the issue of endothelial cell source must be resolved. Endothelial progenitor cells (EPCs) can be noninvasively supplied from the recipient through adult peripheral and umbilical cord blood, as well as derived from induced pluripotent stem cells, alleviating antigenicity issues...
May 26, 2017: Tissue Engineering. Part B, Reviews
https://www.readbyqxmd.com/read/28548488/a-fluorescent-split-aptamer-for-visualizing-rna-rna-assembly-in-vivo
#3
Khalid K Alam, Kwaku D Tawiah, Matthew F Lichte, David Porciani, Donald H Burke
RNA-RNA assembly governs key biological processes and is a powerful tool for engineering synthetic genetic circuits. Characterizing RNA assembly in living cells often involves monitoring fluorescent reporter proteins, which are at best indirect measures of underlying RNA-RNA hybridization events and are subject to additional temporal and load constraints associated with translation and activation of reporter proteins. In contrast, RNA aptamers that sequester small molecule dyes and activate their fluorescence are increasingly utilized in genetically encoded strategies to report on RNA-level events...
May 26, 2017: ACS Synthetic Biology
https://www.readbyqxmd.com/read/28548045/3d-liver-membrane-system-by-co-culturing-human-hepatocytes-sinusoidal-endothelial-and-stellate-cells
#4
Haysam Mohamed Magdy Ahmed, Simona Salerno, Sabrina Morelli, Lidetta Giorno, Loredana De Bartolo
In this study, a designed approach has been utilized for the development of a 3D liver system. This approach makes use of primary human sinusoidal endothelial cells, stellate cells and hepatocytes that are seeded sequentially on hollow fiber membranes (HF) in order to mimic the layers of cells found in vivo. To this purpose modified polyethersulfone (PES) HF membranes were used for the creation of a 3D human liver system in static and dynamic conditions. In order to verify the positive effect of non-parenchymal cells on the maintenance of hepatocyte viability and functions, homotypic cultures of hepatocytes alone on the HF membranes were further investigated...
May 26, 2017: Biofabrication
https://www.readbyqxmd.com/read/28547994/self-assembled-molecular-nanowires-for-high-performance-organic-transistors
#5
Luke R Fleet, James E Stott, Byron Villis, Salahud Din, Michele Serri, Gabriel Aeppli, Sandrine Heutz, Arokia Nathan
While organic semiconductors provide tantalising possibilities for low-cost, light-weight, flexible electronic devices, their current use in transistors - the fundamental building block - is rather limited as their speed and reliability is not competitive with their inorganic counterparts, and is simply too poor for many practical applications. Through self-assembly, highly ordered nanostructures can be prepared that have more competitive transport characteristics, but no simple, scalable method has been discovered that can produce devices based on such nanostructures...
May 26, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28547007/rapid-self-healing-and-anion-selectivity-in-metallosupramolecular-gels-assisted-by-fluorine-fluorine-interactions
#6
Leticia Arnedo-Sánchez, Nonappa, Sandip Bhowmik, Sami Hietala, Rakesh Puttreddy, Manu Lahtinen, Luisa De Cola, Kari Rissanen
Simple ML2 [M = Fe(ii), Co(ii), Ni(ii)] complexes obtained from a perfluoroalkylamide derivative of 4-aminophenyl-2,2',6,2'-terpyridine spontaneously, yet anion selectively, self-assemble into gels, which manifest an unprecedented rapid gel strength recovery, viz. self-healing, and thermal rearrangement in aqueous dimethyl sulfoxide. The key factor for gelation and rheological properties emerges from the fluorine-fluorine interactions between the perfluorinated chains, as the corresponding hydrocarbon derivative did not form metallogels...
May 26, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28546913/genetic-assembly-of-double-layered-fluorescent-protein-nanoparticles-for-cancer-targeting-and-imaging
#7
Seong-Eun Kim, Sung Duk Jo, Koo Chul Kwon, You-Yeon Won, Jeewon Lee
Hepatitis B virus capsid (HBVC), a self-assembled protein nanoparticle comprised of 180 or 240 subunit proteins, is used as a cage for genetic encapsulation of fluorescent proteins (FPs). The self-quenching of FPs is controlled by varying the spacing between FPs within the capsid structure. Double-layered FP nanoparticle possessing cancer cell-targeting capabilities is also produced by additionally attaching FPs and cancer cell receptor-binding peptides (affibodies) to the outer surface of the capsid. The generically modified HBVC with double layers of mCardinal FPs and affibodies (mC-DL-HBVC) exhibit a high fluorescence intensity and a strong photostability, and is efficiently internalized by cancer cells and significantly stable against intracellular degradation...
May 2017: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
https://www.readbyqxmd.com/read/28546071/poly-isoprenylated-ifosfamide-analogs-preactivated-antitumor-agents-as-free-formulation-or-nanoassemblies
#8
Charles Skarbek, Julia Delahousse, Catherine Pioche-Durieu, Sonia Baconnais, Alain Deroussent, Patrice Renevret, Michael Rivard, Didier Desmaele, Thierry Martens, Eric Le Cam, Patrick Couvreur, Angelo Paci
Oxazaphosphorines including cyclophosphamide, trofosfamide and ifosfamide (IFO) belong to the alkylating agent class and are indicated in the treatment of numerous cancers. However, IFO is subject to limiting side-effects in high-dose protocols. To circumvent IFO drawbacks in clinical practices, preactivated IFO analogs were designed to by-pass the toxic metabolic pathway. Among these IFO analogs, some of them showed the ability to self-assemble due to the use of a poly-isoprenyloxy chain as preactivating moiety...
May 22, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28545732/introduction-of-coiled-solid-phase-microextraction-fiber-coated-by-mesoporous-silica-cetyltrimethylammonium-bromide-for-ultra-trace-environmental-analysis
#9
Habib Razmi, Elnaz Marzi Khosrowshahi, Samaneh Farrokhzadeh
In this study, a tiny coiled cupper wire as a novel solid phase microextraction (SPME) fiber was coated with mesoporous silica/cetyltrimethylammonium bromide (MCM-41/CTAB) as an adsorbent by electrochemically assisted self-assembly method and used for the preconcentration of polycyclic aromatic hydrocarbons (PAHs) as model analytes prior to chromatographic determination. Deposition of MCM-41/CTAB on the coiled SPME (C-SPME) fiber resulted in easily controlled and reproducible SPME coatings. Non-calcined MCM-41/CTAB on C-SPME plays a key role in the adsorption of PAHs...
April 9, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28545300/a-large-gap-magnetic-topological-heterostructure-formed-by-subsurface-incorporation-of-a-ferromagnetic-layer
#10
Toru Hirahara, Sergey V Eremeev, Tetsuroh Shirasawa, Yuma Okuyama, Takayuki Kubo, Ryosuke Nakanishi, Ryota Akiyama, Akari Takayama, Tetsuya Hajiri, Shinichiro Ideta, Masaharu Matsunami, Kazuki Sumida, Koji Miyamoto, Yasumasa Takagi, Kiyohisa Tanaka, Taichi Okuda, Toshihiko Yokoyama, Shin-Ichi Kimura, Shuji Hasegawa, Evgueni V Chulkov
Inducing magnetism into topological insulators is intriguing for utilizing exotic phenomena such as the quantum anomalous Hall effect (QAHE) for technological applications. While most studies have focused on doping magnetic impurities to open a gap at the surface-state Dirac point, many undesirable effects have been reported to appear in some cases that makes it difficult to determine whether the gap opening is due to the time-reversal symmetry breaking or not. Furthermore, the realization of the QAHE has been limited to low temperatures...
May 26, 2017: Nano Letters
https://www.readbyqxmd.com/read/28544850/pcpp-adjuvanted-respiratory-syncytial-virus-rsv-sf-subunit-vaccine-self-assembled-supramolecular-complexes-enable-enhanced-immunogenicity-and-protection
#11
Corinne Cayatte, Alexander Marin, Gaurav Manohar Rajani, Kirsten Schneider-Ohrum, Angie Snell Bennett, Jason D Marshall, Alexander K Andrianov
PCPP, a well-defined polyphosphazene macromolecule, has been studied as an immunoadjuvant for a soluble form of the post-fusion glycoprotein (RSV sF) of RSV, which is an attractive vaccine candidate for inducing RSV-specific immunity in mice and humans. We demonstrate that RSV sF-PCPP formulations induce high neutralization titers to RSV comparable to Alum formulations even at a low PCPP dose and protect animals against viral challenge both in the lung and upper respiratory tract. PCPP formulations were also characterized by Th1-biased responses, compared to Th2-biased responses that are more typical for RSV sF alone or RSV sF-Alum formulations, suggesting an inherent immunostimulating activity of the polyphosphazene adjuvant...
May 25, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/28544846/genomic-dna-interactions-mechanize-peptidotoxin-mediated-anti-cancer-nanotherapy
#12
Santosh K Misra, Aaron S Schwartz-Duval, Dipanjan Pan
Host defense peptides (HDPs) are a class of evolutionarily conserved substances of the innate immune response that has been identified as major players in the defense system in many living organisms. Some of the HDPs are also referred as peptidotoxins which offer immense potential for anti-cancer therapy. However, their therapeutic potential is yet to be fully translated mainly due to their off-target toxicity. Here we show that their nano-enabled delivery may become beneficial in controlling their delivery in intra-cellular space...
May 25, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/28544845/self-assembling-zwitterionic-copolymers-as-membrane-selective-layers-with-excellent-fouling-resistance-effect-of-zwitterion-chemistry
#13
Prity Bengani-Lutz, Elisha Converse, Peggy Cebe, Ayse Asatekin
Membranes with high flux, ~1 nm pore size and unprecedented protein fouling resistance were prepared by forming selective layers of self-assembling zwitterionic amphiphilic random copolymers on porous supports by a simple coating method. Random copolymers were prepared from the hydrophobic monomer 2,2,2-trifluoroethyl methacrylate (TFEMA) and four zwitterionic monomers (sulfobetaine methacrylate, sulfobetaine 2-vinylpyridine, sulfobutylbetaine 2-vinylpyridine and 2-methacryloyloxyethyl phosphorylcholine) by free radical polymerization...
May 25, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28544657/a-strategy-to-enhance-the-efficiency-of-quantum-dot-sensitized-solar-cells-by-decreasing-the-electron-recombinations-with-polyoxometalate-tio2-as-the-electronic-interface-layer
#14
Li Chen, Wei-Lin Chen, Jian-Ping Li, Jia-Bo Wang, En-Bo Wang
The serious electron recombination occurring in TiO2/quantum dot sensitizer/electrolyte interface is the key reason for hindering the further efficiency improvement of QDSCs. Polyoxometalate(POM) can be as electron transfer media to decreasing electron recombination of photoelectric device, which is due to the excellent oxidation reduction properties and thermostability. So in this paper, POM/TiO2 electronic interface layer prepared by a simple layer-by-layer self-assembly method is added between FTO and mesoporous TiO2 in the photoanode of the QDSCs, and their effects on the photovoltaic performance are systematically investigated...
May 23, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28544634/hydrogen-bond-driven-self-assembly-between-amidinium-cations-and-carboxylate-anions-a-combined-molecular-dynamics-nmr-spectroscopy-and-single-crystal-x-ray-diffraction-study
#15
Michael Thomas, Thomas Anglim Lagones, Martyna Judd, Mahbod Morshedi, Megan L O'Mara, Nicholas G White
A combination of molecular dynamics (MD), NMR spectroscopy, and single crystal X-ray diffraction (SCXRD) techniques was used to probe the self-assembly of para- and meta-bis(amidinium) compounds with para-, meta-, and ortho-dicarboxylates. Good concordance was observed between the MD and experimental results. In DMSO solution, the systems form several rapidly exchanging assemblies, in part because a range of hydrogen bonding interactions is possible between the amidinium and carboxylate moieties. Upon crystallization, the majority of the systems form 1D supramolecular polymers, which are held together by short N-H⋅⋅⋅O hydrogen bonds...
May 23, 2017: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/28544447/modulation-of-wetting-gradients-by-tuning-the-interplay-between-surface-structuration-and-anisotropic-molecular-layers-with-bipolar-electrochemistry
#16
Laurent Bouffier, Stéphane Reculusa, Valérie Ravaine, Alexander Kuhn
A new simple and versatile method for the preparation of surface wetting gradients is proposed. It is based on the combination of electrode surface structuration introduced by a sacrificial template approach and the formation of a tuneable molecular gradient by bipolar electrochemistry. The gradient involves the formation of a self-assembled monolayer on gold surface by selecting an appropriate thiol molecule and the subsequent reductive desorption by means of bipolar electrochemistry. Under these conditions, the completion of the reductive desorption process evolves along the bipolar surface with a maximum strength localized at the cathodic edge and a decreasing driving force toward the middle of the surface...
May 22, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28544434/strain-stiffening-hydrogels-through-self-assembly-and-covalent-fixation-of-semi-flexible-fibers
#17
Rint P Sijbesma, Marcos Fernandez-Castano Romera, Clément Guibert, Ilja K Voets, Cornelis Storm
Biomimetic, strain-stiffening materials are reported, made through self-assembly and covalent fixation of small building blocks to form fibrous hydrogels able to stiffen by an order of magnitude in response to applied stress. The gels consist of semi-flexible rodlike micelles of bisurea bolaamphiphiles with oligo(ethylene oxide) (EO) outer blocks and a polydiacetylene (PDA) backbone. The micelles are fibers composed of 9-10 ribbons. A gelation method based on Cu-catalyzed azide-alkyne cycloaddition (CuAAC) was developed that leads to strain-stiffening hydrogels with unusual yet universal linear and nonlinear stress-strain response...
May 24, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28544383/self-assembled-biomimetic-chloroplast-coupled-photoenzymatic-reaction-for-sustainable-synthesis-of-fuel
#18
Xuehai Yan, Kai Liu, Chengqian Yuan, Qianli Zou, Zengchun Xie
Prototypes of biosystems provide good blueprints for the design and creation of biomimetic systems. However, mimicking both the sophisticated natural structures and their complex biological functions still remains a great challenge. Herein, biomimetic chloroplasts have been fabricated by one-step bio-inspired amino acid mineralization and simultaneous integration of catalytically active units. Hierarchically structured crystals are obtained by metal ion-directed self-assembly of cystine (the oxidized dimer form of the amino acid cysteine), with porous structure and stacking nanorods, which show similar architectural principles to chloroplasts...
May 22, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28544231/dual-responsive-molecular-switches-based-on-dithienylethene-ru-ii-organometallics-in-self-assembled-monolayers-operating-at-low-voltage
#19
Andrea Mulas, Xiaoyan He, Yves-Marie Hervault, Lucie Norel, Stéphane Rigaut, Corinne Lagrost
Two carbon-rich ruthenium complexes bearing a dithienylethene (DTE) unit and a hexylthiol spacer were designed to be attached on gold surfaces. Both compounds display photochemically-driven switching properties, allowing reversible conversion from open to closed forms of the DTE units upon irradiation in solution. In contrast, only the bimetallic complex undergoes an efficient electrochemical ring closure at low potential, (0.5 V vs SCE), whereas the monometallic complex show a simple one electron reversible redox event...
May 22, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28544167/molecular-graph-paper
#20
Marcin Lindner, Michal Valášek, Marcel Mayor, Timo Frauhammer, Wulf Wulfhekel, Lukas Gerhard
We present a self-assembled template of tetraphenylmethane-based variants on a Au(111) surface which feature a periodic lateral arrangement of acetyl groups sticking out of the molecular film. Using the tip of a scanning tunneling microscope, this acetyl group can be removed in a spatially controlled way without a significant effect on the remaining molecular assembly. The chemically modified molecule can readily be distinguished from the original ones such that information can be engraved in the molecular film...
May 24, 2017: Angewandte Chemie
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