keyword
MENU ▼
Read by QxMD icon Read
search

crystalization

keyword
https://www.readbyqxmd.com/read/28728041/multi-structure-docking-analysis-of-bace1-crystal-structures-and-non-peptidic-ligands
#1
Zahra Haghighijoo, Bahram Hemmateenejad, Najmeh Edraki, Ramin Miri, Saeed Emami
In order to design novel non-peptidic inhibitors of BACE1, many research groups have attempted using computational studies including docking analyses. Since there are too many 3D structures for BACE1 in the protein database, the selection of suitable crystal structures is a key prerequisite for the successful application of molecular docking. We employed a multi-structure docking protocol. In which 615 ligands' structures were docked into 150 BACE1 structures. The large number of the resultant docking scores were post-processed by different data analysis methods including exploratory data analysis, regression analysis and discriminant analysis...
June 28, 2017: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/28727915/improving-accuracy-diversity-and-speed-with-prime-macrocycle-conformational-sampling
#2
Dan Sindhikara, Steven A Spronk, Tyler Day, Ken Borrelli, Daniel L Cheney, Shana L Posy
A novel method for exploring macrocycle conformational space, Prime Macrocycle Conformational Sampling (Prime-MCS), is introduced and evaluated in the context of other available algorithms (Molecular Dynamics, LowModeMD in MOE, and MacroModel Baseline Search). The algorithms were benchmarked on a dataset of 208 macrocycles which was curated for diversity from the Cambridge Structural Database, the Protein Databank, and the Biologically Interesting Molecule Reference Dictionary. The algorithms were evaluated in terms of accuracy (ability to reproduce the crystal structure), diversity (coverage of conformational space), and computational speed...
July 20, 2017: Journal of Chemical Information and Modeling
https://www.readbyqxmd.com/read/28727826/germline-and-reproductive-tract-effects-intensify-in-male-mice-with-successive-generations-of-estrogenic-exposure
#3
Tegan S Horan, Alyssa Marre, Terry Hassold, Crystal Lawson, Patricia A Hunt
The hypothesis that developmental estrogenic exposure induces a constellation of male reproductive tract abnormalities is supported by experimental and human evidence. Experimental data also suggest that some induced effects persist in descendants of exposed males. These multi- and transgenerational effects are assumed to result from epigenetic changes to the germline, but few studies have directly analyzed germ cells. Typically, studies of transgenerational effects have involved exposing one generation and monitoring effects in subsequent unexposed generations...
July 2017: PLoS Genetics
https://www.readbyqxmd.com/read/28727767/exploring-the-binding-pathways-of-the-14-3-3%C3%AE-protein-structural-and-free-energy-profiles-revealed-by-hamiltonian-replica-exchange-molecular-dynamics-with-distancefield-distance-restraints
#4
Gabor Nagy, Chris Oostenbrink, Jozef Hritz
The 14-3-3 protein family performs regulatory functions in eukaryotic organisms by binding to a large number of phosphorylated protein partners. Whilst the binding mode of the phosphopeptides within the primary 14-3-3 binding site is well established based on the crystal structures of their complexes, little is known about the binding process itself. We present a computational study of the process by which phosphopeptides bind to the 14-3-3ζ protein. Applying a novel scheme combining Hamiltonian replica exchange molecular dynamics and distancefield restraints allowed us to map and compare the most likely phosphopeptide-binding pathways to the 14-3-3ζ protein...
2017: PloS One
https://www.readbyqxmd.com/read/28727460/2d-organic-superlattice-promoted-via-combined-action-of-%C3%AF-%C3%AF-stacking-and-dipole-dipole-interaction-in-discotic-liquid-crystals
#5
Wanying Zhang, Shuai-Feng Zhang, Zhenhu Zhang, Huanzhi Yang, Ao Zhang, Xingtian Hao, Jianchuang Wang, Chunxiu Zhang, Jialing Pu
A series of discotic liquid crystals based on hexapentyloxytriphenylene (HAT5) have been investigated where one out of the six ether side chains of a triphenylene core was replaced by an ester side chain and named for 5a-5h. During the process of studying these compounds, the characteristic straight line defect of ordered columnar structure was identified by polarizing optical microscopy (POM) and liquid crystal state over a wide temperature range was obtained by differential scanning calorimetry (DSC). Basic phase structure and molecular arrangement were assigned by one-dimensional wide-angle X-ray diffraction (1D WAXD), small angle X-ray scattering (SAXS), two-dimensional wide-angle X-ray diffraction (2D WAXD) and transmission electron microscope (TEM)...
July 20, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28727450/carbon-nanotube-reinforced-polymer-stabilized-liquid-crystal-device-lowered-and-thermally-invariant-threshold-with-accelerated-dynamics
#6
Subbarao Krishna Prasad, Marlin Baral, Adhigan Murali, Sellamuthu N Jaisankar
Polymer stabilized liquid crystal (PSLC) devices comprise a polymer matrix in an otherwise continuous phase of liquid crystal. The fibrils of the polymer provide, even in the bulk, virtual surfaces with finite anchoring energy resulting in attractive electro-optic properties. Here we describe a novel variation of the PSLC device fabricated by reinforcing the polymer matrix with polymer-capped single-walled carbon nanotubes (CNTs). The most important outcome of this strengthening of the polymer strands is that the threshold voltage associated with the electro-optic switching becomes essentially temperature independent in marked contrast to the significant thermal variation seen in the absence of the nanotubes...
July 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28727444/fosfomycin-biosynthesis-via-transient-cytidylylation-of-2-hydroxyethylphosphonate-by-the-bifunctional-fom1-enzyme
#7
Su-Hee Cho, Seung-Young Kim, Takeo Tomita, Taro Shiraishi, Jin-Soo Park, Shusuke Sato, Fumitaka Kudo, Tadashi Eguchi, Nobutaka Funa, Makoto Nishiyama, Tomohisa Kuzuyama
Fosfomycin is a wide-spectrum phosphonate antibiotic that is used clinically to treat cystitis, tympanitis, etc. Its biosynthesis starts with the formation of a carbon-phosphorus bond catalyzed by the phosphoenolpyruvate phosphomutase Fom1. We identified an additional cytidylyltransferase (CyTase) domain at the Fom1 N-terminus in addition to the phosphoenolpyruvate phosphomutase domain at the Fom1 C-terminus. Here, we demonstrate that Fom1 is bifunctional and that the Fom1 CyTase domain catalyzes the cytidylylation of the 2-hydroxyethylphosphonate (HEP) intermediate to produce cytidylyl-HEP...
July 20, 2017: ACS Chemical Biology
https://www.readbyqxmd.com/read/28727442/manipulating-semicrystalline-polymers-in-confinement
#8
Nitin Shingne, Markus Geuss, Thomas Thurn-Albrecht, Hans-Werner Schmidt, Carmen Mijangos, Martin Steinhart, Jaime Martin
Because final properties of nanoscale polymeric structures are largely determined by the solid-state microstructure of the confined polymer, it is imperative not only to understand how the microstructure of polymers develops under nanoscale confinement but also to establish means to manipulate it. Here we present a series of processing strategies, adapted from methods used in bulk polymer processing, that allow to control the solidification of polymer materials confined in the nanopores of anodic aluminium oxide (AAO) templates...
July 20, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28727427/high-throughput-synthesis-and-structure-of-zeolite-zsm-43-with-two-directional-8-ring-channels
#9
Tom Willhammar, Jie Su, Yifeng Yun, Xiaodong Zou, Mobae Afeworki, Simon C Weston, Hilda B Vroman, William W Lonergan, Karl G Strohmaier
The aluminosilicate zeolite ZSM-43 (where ZSM = Zeolite Socony Mobil) was first synthesized more than 3 decades ago, but its chemical structure remained unsolved because of its poor crystallinity and small crystal size. Here we present optimization of the ZSM-43 synthesis using a high-throughput approach and subsequent structure determination by the combination of electron crystallographic methods and powder X-ray diffraction. The synthesis required the use of a combination of both inorganic (Cs(+) and K(+)) and organic (choline) structure-directing agents...
July 20, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28727415/hydrophobic-nanosized-all-silica-beta-zeolite-efficient-synthesis-and-adsorption-application
#10
Zhiguo Zhu, Hao Xu, Jingang Jiang, Hai-Hong Wu, Peng Wu
All-silica Beta zeolite, synthesized by conventional hydroxide route, usually possesses small crystal size of a few hundred nanometers but poor hydrophobicity, whereas the fluoride-mediated one exhibits to be highly hydrophobic but microsized. To obtain nanosized all-silica Beta zeolite with excellent hydrophobicity, an innovative and efficient hydrothermal route via interzeolite transformation for synthesizing all-silica Beta zeolite is proposed in present study. With the assistance of Beta seeds and tetraethylammonium hydroxide as the structure-directing agent, siliceous Beta zeolite is well crystallized at a high solid yield via dissolution-recrystallization of all-silica ITQ-1 crystals at an extremely low water content (H2O/SiO2 molar ratio of 1)...
July 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28727246/recognition-and-extraction-of-cesium-hydroxide-and-carbonate-using-a-neutral-multitopic-ion-pair-receptor
#11
Qing He, Gretchen Marie Peters, Vincent M Lynch, Jonathan L Sessler
Current approaches to lowering the pH of basic media rely on the addition of a proton source. An alternative approach is described here that involves the liquid-liquid extraction-based removal of cesium salts, specifically CsOH and Cs2CO3, from highly basic media. A multitopic ion-pair receptor (2) is used that can recognize and extract the hydroxide and carbonate anions as their cesium salts, as confirmed by 1H NMR spectroscopic titrations, ICP-MS, single-crystal structural analyses and theoretical calculations...
July 20, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28727236/structural-and-electronic-flexibility-in-hydrides-of-zintl-phases-with-tetrel-hydrogen-and-tetrel-tetrel-bonds
#12
Henry Auer, Holger Kohlmann
The hydrogenation of Zintl phases enables the formation of new structural entities with main group element-hydrogen bonds in the solid state. The hydrogenation of SrSi, BaSi and BaGe yields the hydrides SrSiH5/3-x, BaSiH5/3-x and BaGeH5/3-x, whose crystal structures were solved by a combination of X-ray, neutron and electron diffraction. Layers of connected HSr4 (HBa4) tetrahedra containing hydride ions alternate with layers of infinite single- and double-chain polyanions, where hydrogen atoms are covalently bound to silicon and germanium...
July 20, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28727219/fractal-crystals-hunting-the-hidden-dimension-in-nanoporous-materials
#13
Lei Wang, Shengcai Zhu, Meikun Shen, Haiwen Tian, Songhai Xie, Hongbin Zhang, Yahong Zhang, Yi Tang
Screw dislocation structure in crystal are origin of symmetry breaking in a wide range of dense phase crystals. Preparation of such analogous structure in framework phase crystals is of great importance in zeolites but still a challenge. On the basis of crystal structure-solving and model building, we found that the two specific intergrowths in MTW zeolite produce this complex fractal and spiral structure. With the structure determined parameters (spiral pitch h, screw angle θ and spatial angle ψ) of Burgers circuit, the screw dislocation structure can be constructed by two different dimensional intergrowth sections...
July 20, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28727129/potentialization-of-n-a-tosyl-l-phenylalanine-chloromethyl-ketone-tpck-cytotoxic-activity-by-2-1-adamantylamino-6-methylpyridine-adamp-in-human-ovarian-cancer-cells
#14
Jacek Sieńko, Witold Lasek, Justyna Teliga-Czajkowska, Roman Smolarczyk, Krzysztof Czajkowski
OBJECTIVES: TNF is one of the key cytokines involved in cancer development. TNF signaling can result in both stimulating and inhibitory signals that can result in opposite biological effects in cancerogenesis. 2-(1-adamantylamino)-6-methylpyridine (AdAMP) enhances TNF secretion whereas N-a-tosyl-L-phenylalanine chloromethyl ketone (TPCK) is a NF-κB inhibitor potentially stimulating proapoptotic TNF signals. The aim of the study was to assess the effect of TPCK in combination with AdAMP on human ovarian cells...
2017: Ginekologia Polska
https://www.readbyqxmd.com/read/28726970/a-homeotropic-main-chain-tolane-type-liquid-crystal-elastomer-film-exhibiting-high-anisotropic-thermal-conductivity
#15
Si-Jia Ge, Ti-Peng Zhao, Meng Wang, Lin-Lin Deng, Bao-Ping Lin, Xue-Qin Zhang, Ying Sun, Hong Yang, Er-Qiang Chen
The development of pure polymeric films with anisotropic thermal conductivities for electronic device packaging applications has attracted intense scientific attention. In order to enhance the polymeric film's normal-direction thermal conductivity, homeotropic alignment of macromolecular chains is the primary concern. One of the promising preparation strategies is to perform in situ photopolymerization of homeotropic-oriented liquid crystal monomers. In this work, we design and synthesize a novel tolane-core thiol-ene-tailed liquid crystal monomer...
July 20, 2017: Soft Matter
https://www.readbyqxmd.com/read/28726953/4-4-di-tert-butyl-6-1h-tetrazol-5-yl-2-2-bipyridine-modification-of-a-highly-selective-n-donor-ligand-for-the-separation-of-trivalent-actinides-from-lanthanides
#16
Martin M Maiwald, Anna T Wagner, Jochen Kratsch, Andrej Skerencak-Frech, Michael Trumm, Andreas Geist, Peter W Roesky, Petra J Panak
In the present work, the complexation and extraction behaviour of 4,4'di-tert-butyl-6-(1H-tetrazol-5-yl)-2,2'-bipyridine (HN4(t)bubipy) towards trivalent actinides (An(iii)) and lanthanides (Ln(iii)) is studied by spectroscopic methods, liquid-liquid extraction, and quantum chemical calculations. The ligand synthesis of HN4(t)bubipy as well as its application in coordination chemistry of the 4f elements is described. Reaction of HN4(t)bubipy with [Ln(NO3)3·6H2O] (Ln = Sm, Eu) results in [H2N4(t)bubipy](+)[Ln(N4(t)bubipy)(NO3)3(H2O)](-)...
July 20, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28726935/strength-character-and-directionality-of-halogen-bonds-involving-cationic-halogen-bond-donors
#17
Kevin E Riley, Khanh-An Tran
Halogen bonds involving cationic halogen bond donors and anionic halogen bond acceptors have recently been recognized as being important in stabilizing the crystal structures of many salts. Theoretical characterization of these types of interactions, most importantly in terms of their directionality, has been limited. Here we generate high-quality symmetry adapted perturbation theory potential energy curves of a H3N-C[triple bond, length as m-dash]C-Br(+)Cl(-) model system in order to characterize halogen bonds involving charged species, in terms of contributions from electrostatics, exchange, induction, and dispersion, with special emphasis on analyzing contributions that are most responsible for the directionality of these interactions...
July 20, 2017: Faraday Discussions
https://www.readbyqxmd.com/read/28726930/competition-and-selectivity-in-supramolecular-synthesis-structural-landscape-around-1-pyridylmethyl-2-2-biimidazoles
#18
C A Gunawardana, J Desper, A S Sinha, M Ðaković, C B Aakeröy
Three isomeric forms of 1-(pyridylmethyl)-2,2'-biimidazole, A1-A3, have been synthesized and subjected to systematic co-crystallizations with selected hydrogen- and halogen-bond donors in order to explore the impact of electrostatics and geometry on the resulting supramolecular architectures. The solid-state supramolecular behavior of A1-A3 is largely consistent in halogen-bonded co-crystals. Only two types of primary interactions, the N-HN/NH-N homomeric hydrogen-bond interactions responsible for the pairing of biimidazole moieties and the IN(pyridine) halogen bonds responsible for the co-crystal formation and structure extension, are present in these systems...
July 20, 2017: Faraday Discussions
https://www.readbyqxmd.com/read/28726887/standard-and-rapid-scan-infrared-spectroscopic-studies-of-o-xylene-transformations-in-terms-of-pore-arrangement-of-10-ring-zeolites-2d-cos-analysis
#19
Kinga Gołąbek, Karolina A Tarach, Kinga Góra-Marek
This study attempts to offer an insight into o-xylene isomerization process in terms of steric constraints of 10-ring zeolites. The zeolites under investigation, i.e. ZSM-5, IM-5 and TNU-9, have purely microporous structures and crystals with the same shape and offer comparable protonic functionality, both in manner of amount and strength of Si(OH)Al groups. Under these conditions, micropore topology is recognised to deliver differentiated catalytic performance of each zeolitic structure. Moreover, 10-ring zeolites of reduced dimensionality, i...
July 20, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28726864/bn-nanoflake-quantum-dot-arrays-structural-stability-and-electronic-and-half-metallic-properties
#20
R Hu, Z H Zhang, Z Q Fan
New one-dimensional (1D) crystals, 1D quantum-dot arrays(1D QDAs), are proposed and constructed by an ordered arrangement of zigzag-edged triangular h-BN nanoflakes. Their geometrical stability is confirmed by the calculated binding energy, phonon dispersion and molecular dynamics simulation. These 1D QDAs demonstrate different quantum confinement effects on electronic and half-metallic properties due to different linking modes. For example, in the nonmagnetic state, different 1D QDAs are predicted to be semiconductors or metals remarkably depending on their linking manner, whereas in the ferromagnetic state, they are found to be all prominent half-metals but with greatly different gaps from ∼0...
July 20, 2017: Physical Chemistry Chemical Physics: PCCP
keyword
keyword
98975
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"