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https://www.readbyqxmd.com/read/28212595/preparation-and-characterization-of-gold-nanoparticles-in-the-presence-of-citrate-and-soybean-seed-extract-in-an-acidic-conditions
#1
Ebrahim Izadi, Ali Rasooli, Abolfazl Akbarzadeh, Soodabeh Davaran
Through the present study, an eco-friendly method was used to synthesize the gold nanoparticles (GNPs) by using the sodium citrate and extract of the soybean seed as reducing the agents at PH 3. X-Ray diffraction (XRD) method was used to evaluate the crystal structure of as-synthesized NPs and it's revealed that this method leads to well crystallized GNPs. In order to determine the particle size and their distribution, field emission scanning microscopy (FE-SEM) and dynamic light scattering (DLS) were used...
February 17, 2017: Drug Research
https://www.readbyqxmd.com/read/28212347/molecularly-imprinted-sol-gel-based-qcm-sensor-arrays-for-the-detection-and-recognition-of-volatile-aldehydes
#2
Chuanjun Liu, Bartosz Wyszynski, Rui Yatabe, Kenshi Hayashi, Kiyoshi Toko
The detection and recognition of metabolically derived aldehydes, which have been identified as important products of oxidative stress and biomarkers of cancers; are considered as an effective approach for early cancer detection as well as health status monitoring. Quartz crystal microbalance (QCM) sensor arrays based on molecularly imprinted sol-gel (MISG) materials were developed in this work for highly sensitive detection and highly selective recognition of typical aldehyde vapors including hexanal (HAL); nonanal (NAL) and bezaldehyde (BAL)...
February 16, 2017: Sensors
https://www.readbyqxmd.com/read/28212032/chrodrimanins-k-n-and-related-meroterpenoids-from-the-fungus-penicillium-sp-scs-kfd09-isolated-from-a-marine-worm-sipunculus-nudus
#3
Fan-Dong Kong, Qing-Yun Ma, Sheng-Zhuo Huang, Pei Wang, Jun-Feng Wang, Li-Man Zhou, Jing-Zhe Yuan, Hao-Fu Dai, You-Xing Zhao
Six new meroterpenoids, chrodrimanins K-N (1-4), including two uncommon chlorinated ones (1 and 2), and verruculides B2 (5) and B3 (6), as well as seven known ones (7-13), were isolated from the fermentation broth of Penicillium sp. SCS-KFD09 isolated from a marine worm, Sipunculus nudus, from Haikou Bay, China. The structures including the absolute configurations of the new compounds were unambiguously elucidated by spectroscopic data, X-ray diffraction analysis, and ECD spectra analysis along with quantum ECD calculations...
February 17, 2017: Journal of Natural Products
https://www.readbyqxmd.com/read/28212012/-meyeniins-a-c-novel-hexahydroimidazo-1-5-c-thiazole-derivatives-from-the-tubers-of-lepidium-meyenii-complete-structural-elucidation-by-biomimetic-synthesis-and-racemic-crystallization
#4
Min Zhou, Hang-Ying Ma, Zhi-Hua Liu, Guang-Yu Yang, Gang Du, Yan-Qing Ye, Gan-Peng Li, Qiu-Fen Hu
(+)-Meyeniins A-C (1-3), a novel class of sulfur-containing hexahydroimidazo[1,5-c]thiazole derivatives, were isolated from the tubers of Lepidium meyenii cultivated in Lijiang, Yunnan Province, China. Guided by their biosynthetic hypothesis, a stereocontrolled biomimetic synthesis of meyeniins A-C and their individual enantiomers was efficiently accomplished by a combination of a condensation reaction and Edman degradation. The formation of high-quality crystals for X-ray crystallography occurred much more readily from a racemic mixture of (±)-meyeniin A than with the single enantiomer alone in this case...
February 17, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28211934/a-computational-assessment-of-the-electronic-thermoelectric-and-defect-properties-of-bournonite-cupbsbs3-and-related-substitutions
#5
Alireza Faghaninia, Guodong Yu, Umut Aydemir, Max Wood, Wei Chen, Gian-Marco Rignanese, G Jeffrey Snyder, Geoffroy Hautier, Anubhav Jain
Bournonite (CuPbSbS3) is an earth-abundant mineral with potential thermoelectric applications. This material has a complex crystal structure (space group Pmn21 #31) and has previously been measured to exhibit a very low thermal conductivity (κ < 1 W m(-1) K(-1) at T ≥ 300 K). In this study, we employ high-throughput density functional theory calculations to investigate how the properties of the bournonite crystal structure change with elemental substitutions. Specifically, we compute the stability and electronic properties of 320 structures generated via substitutions {Na-K-Cu-Ag}{Si-Ge-Sn-Pb}{N-P-As-Sb-Bi}{O-S-Se-Te} in the ABCD3 formula...
February 17, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28211915/structure-of-the-shr-scr-heterodimer-bound-to-the-bird-idd-transcriptional-factor-jkd
#6
Yoshinori Hirano, Masahiro Nakagawa, Tomoe Suyama, Kohji Murase, Maya Shirakawa, Seiji Takayama, Tai-Ping Sun, Toshio Hakoshima
The plant-specific GAI, RGA and SCR (GRAS) family proteins play critical roles in plant development and signalling. Two GRAS proteins, SHORT-ROOT (SHR) and SCARECROW (SCR), cooperatively direct asymmetric cell division and the patterning of root cell types by transcriptional control in conjunction with BIRD/INDETERMINATE DOMAIN (IDD) transcription factors, although precise details of these specific interactions and actions remain unknown. Here, we present the crystal structures of the SHR-SCR binary and JACKDAW (JKD)/IDD10-SHR-SCR ternary complexes...
February 17, 2017: Nature Plants
https://www.readbyqxmd.com/read/28211904/structural-and-functional-characterization-of-deep-sea-thermophilic-bacteriophage-gve2-hnh-endonuclease
#7
Likui Zhang, Dandan Xu, Yanchao Huang, Xinyuan Zhu, Mianwen Rui, Ting Wan, Xin Zheng, Yulong Shen, Xiangdong Chen, Kesen Ma, Yong Gong
HNH endonucleases in bacteriophages play a variety of roles in the phage lifecycle as key components of phage DNA packaging machines. The deep-sea thermophilic bacteriophage Geobacillus virus E2 (GVE2) encodes an HNH endonuclease (GVE2 HNHE). Here, the crystal structure of GVE2 HNHE is reported. This is the first structural study of a thermostable HNH endonuclease from a thermophilic bacteriophage. Structural comparison reveals that GVE2 HNHE possesses a typical ββα-metal fold and Zn-finger motif similar to those of HNH endonucleases from other bacteriophages, apart from containing an extra α-helix, suggesting conservation of these enzymes among bacteriophages...
February 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28211741/enhanced-crystal-growth-in-binary-lennard-jones-mixtures
#8
M Radu, K Kremer
We study the crystal growth in binary Lennard-Jones mixtures by molecular dynamics simulations. Growth dynamics, the structure of the liquid-solid interfaces as well as droplet incorporation into the crystal vary with solution properties. For demixed systems we observe a strongly enhanced crystal growth at the cost of enclosed impurities. Furthermore, we find different interface morphologies depending on solubility. We relate our observations to growth mechanisms based on the Gibbs-Thomson effect as well as to predictions of the Kardar-Parisi-Zhang theory in 2+1 dimensions...
February 3, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28211675/synthesis-of-orthorhombic-perovskite-type-znsno3-single-crystal-nanoplates-and-their-application-in-energy-harvesting
#9
Runjiang Guo, Yiping Guo, Huanan Duan, Hua Li, Hezhou Liu
In recent years, the lead-free piezoelectric nanogenerators have attracted much attention, because of their great potential for harvesting energy from our environment. Here, we report on the first synthesis of two-dimensional (2D) single crystal ZnSnO3 hexagon nanoplates and fabrication of nanogenerators based on the single crystal ZnSnO3 nanoplates. The orthorhombic perovskite structured ZnSnO3 nanoplates with the (111) facets exposed at the surface of the plates are successfully synthesized via a one-step hydrothermal reaction...
February 17, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28211544/upper-critical-field-reaches-90%C3%A2-tesla-near-the-mott-transition-in-fulleride-superconductors
#10
Y Kasahara, Y Takeuchi, R H Zadik, Y Takabayashi, R H Colman, R D McDonald, M J Rosseinsky, K Prassides, Y Iwasa
Controlled access to the border of the Mott insulating state by variation of control parameters offers exotic electronic states such as anomalous and possibly high-transition-temperature (Tc) superconductivity. The alkali-doped fullerides show a transition from a Mott insulator to a superconductor for the first time in three-dimensional materials, but the impact of dimensionality and electron correlation on superconducting properties has remained unclear. Here we show that, near the Mott insulating phase, the upper critical field Hc2 of the fulleride superconductors reaches values as high as ∼90 T-the highest among cubic crystals...
February 17, 2017: Nature Communications
https://www.readbyqxmd.com/read/28211532/structure-of-a-lov-protein-in-apo-state-and-implications-for-construction-of-lov-based-optical-tools
#11
Vladimir Arinkin, Joachim Granzin, Katrin Röllen, Ulrich Krauss, Karl-Erich Jaeger, Dieter Willbold, Renu Batra-Safferling
Unique features of Light-Oxygen-Voltage (LOV) proteins like relatively small size (~12-19 kDa), inherent modularity, highly-tunable photocycle and oxygen-independent fluorescence have lately been exploited for the generation of optical tools. Structures of LOV domains reported so far contain a flavin chromophore per protein molecule. Here we report two new findings on the short LOV protein W619_1-LOV from Pseudomonas putida. First, the apo-state crystal structure of W619_1-LOV at 2.5 Å resolution reveals conformational rearrangements in the secondary structure elements lining the chromophore pocket including elongation of the Fα helix, shortening of the Eα-Fα loop and partial unfolding of the Eα helix...
February 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28211456/learning-from-data-to-design-functional-materials-without-inversion-symmetry
#12
Prasanna V Balachandran, Joshua Young, Turab Lookman, James M Rondinelli
Accelerating the search for functional materials is a challenging problem. Here we develop an informatics-guided ab initio approach to accelerate the design and discovery of noncentrosymmetric materials. The workflow integrates group theory, informatics and density-functional theory to uncover design guidelines for predicting noncentrosymmetric compounds, which we apply to layered Ruddlesden-Popper oxides. Group theory identifies how configurations of oxygen octahedral rotation patterns, ordered cation arrangements and their interplay break inversion symmetry, while informatics tools learn from available data to select candidate compositions that fulfil the group-theoretical postulates...
February 17, 2017: Nature Communications
https://www.readbyqxmd.com/read/28211453/mechanism-of-partial-agonism-in-ampa-type-glutamate-receptors
#13
Hector Salazar, Clarissa Eibl, Miriam Chebli, Andrew Plested
Neurotransmitters trigger synaptic currents by activating ligand-gated ion channel receptors. Whereas most neurotransmitters are efficacious agonists, molecules that activate receptors more weakly-partial agonists-also exist. Whether these partial agonists have weak activity because they stabilize less active forms, sustain active states for a lesser fraction of the time or both, remains an open question. Here we describe the crystal structure of an α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptor (AMPAR) ligand binding domain (LBD) tetramer in complex with the partial agonist 5-fluorowillardiine (FW)...
February 17, 2017: Nature Communications
https://www.readbyqxmd.com/read/28211270/uniform-patchy-platelets-by-seeded-heteroepitaxial-growth-of-crystallizable-polymer-blends-in-two-dimensions
#14
Ali Nazemi, Xiaoming He, Liam R MacFarlane, Robert L Harniman, Ming-Siao Hsiao, Mitchell A Winnik, Charl F J Faul, Ian Manners
Rectangular platelets formed by the self-assembly of block copolymers in selective solvents are of interest for a range of applications. Recently we showed that the seeded growth of crystallizable blends of a block copolymer and homopolymer yields well-defined, low dispersity examples of these two-dimensional (2D) structures. The key feature was the use of the same crystallizable polymer segment in the seed and blend components to enable an efficient homoepitaxial growth process. Herein we demonstrate that this 2D crystallization-driven self-assembly approach can be extended to heteropitaxial growth by the use of different crystallizable polymers with compatible crystal structures...
February 17, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28211267/efficient-and-selective-uptake-of-tco4-by-a-cationic-metal-organic-framework-material-with-open-ag-sites
#15
Daopeng Sheng, Lin Zhu, Chao Xu, Chengliang Xiao, Yanlong Wang, Yaxing Wang, Lanhua Chen, Juan Diwu, Jing Chen, Zhifang Chai, Thomas E Albrecht-Schmitt, Shuao Wang
99Tc is one of the most problematic radioisotopes in used nuclear fuel owing to its combined features of high fission yield, long half-life, and high environmental mobility. There are only a handful of functional materials that can remove TcO4- anion from aqueous solution and identifying for new, stable materials with high anion-exchange capacities, fast kinetics, and good selectivity remains a challenge. We report here an 8-fold interpenetrated three-dimensional cationic metal-organic framework material, SCU-100, which is assembled from a tetradentate neutral nitrogen-donor ligand and two-coordinate Ag+ cations as potential open metal sites...
February 17, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28210731/pressure-driven-phase-transition-mechanisms-revealed-by-quantum-chemistry-l-serine-polymorphs
#16
Denis A Rychkov, Jernej Stare, Elena V Boldyreva
The present study delivers a computational approach for the understanding of the mechanism of phase transitions between polymorphs of small organic molecules. By using state of the art periodic DFT calculations augmented with dispersion corrections and an external stress tensor together with gas-phase cluster calculations, we thoroughly explained the reversible phase transitions of three polymorphs of the model system, namely crystalline l-serine in the pressure range up to 8 GPa. This study has shown that at the macroscopic level the main driving force of the phase transitions is the decrease in the volume of the crystal unit cell, which contributes to the enthalpy difference between the two forms, but not to the difference in their internal crystal energies...
February 17, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28209973/structural-basis-for-fragmenting-the-exopolysaccharide-of-acinetobacter-baumannii-by-bacteriophage-%C3%AE-ab6-tailspike-protein
#17
I-Ming Lee, I-Fan Tu, Feng-Ling Yang, Tzu-Ping Ko, Jiahn-Haur Liao, Nien-Tsung Lin, Chung-Yi Wu, Chien-Tai Ren, Andrew H-J Wang, Ching-Ming Chang, Kai-Fa Huang, Shih-Hsiung Wu
With an increase in antibiotic-resistant strains, the nosocomial pathogen Acinetobacter baumannii has become a serious threat to global health. Glycoconjugate vaccines containing fragments of bacterial exopolysaccharide (EPS) are an emerging therapeutic to combat bacterial infection. Herein, we characterize the bacteriophage ΦAB6 tailspike protein (TSP), which specifically hydrolyzed the EPS of A. baumannii strain 54149 (Ab-54149). Ab-54149 EPS exhibited the same chemical structure as two antibiotic-resistant A...
February 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28209972/frustration-of-crystallisation-by-a-liquid-crystal-phase
#18
Christopher D Syme, Joanna Mosses, Mario González-Jiménez, Olga Shebanova, Finlay Walton, Klaas Wynne
Frustration of crystallisation by locally favoured structures is critically important in linking the phenomena of supercooling, glass formation, and liquid-liquid transitions. Here we show that the putative liquid-liquid transition in n-butanol is in fact caused by geometric frustration associated with an isotropic to rippled lamellar liquid-crystal transition. Liquid-crystal phases are generally regarded as being "in between" the liquid and the crystalline state. In contrast, the liquid-crystal phase in supercooled n-butanol is found to inhibit transformation to the crystal...
February 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28209025/cmos-compatible-fabrication-for-photonic-crystal-based-nanofluidic-structure
#19
Wang Peng, Youping Chen, Wu Ai, Dailin Zhang, Han Song, Hui Xiong, Pengcheng Huang
Photonic crystal (PC)-based devices have been widely used since 1990s, while PC has just stepped into the research area of nanofluidic. In this paper, photonic crystal had been used as a complementary metal oxide semiconductors (CMOS) compatible part to create a nanofluidic structure. A nanofluidic structure prototype had been fabricated with CMOS-compatible techniques. The nanofluidic channels were sealed by direct bonding polydimethylsiloxane (PDMS) and the periodic gratings on photonic crystal structure...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28208717/final-demonstration-of-the-co-identity-of-lipiarmycin-a3-and-tiacumicin-b-fidaxomicin-through-single-crystal-x-ray-analysis
#20
Stefano Serra, Luciana Malpezzi, Angelo Bedeschi, Claudio Fuganti, Piera Fonte
Lipiarmycin A3 and tiacumicin B possess the same chemical structure and have been considered identical till recently, when some authors have suggested the possibility of a minor difference between the chemical structures of the two antibiotics. In this work we performed a comparative X-ray analysis of lipiarmycin A3 and tiacumicin B. Although the commercial samples of the aforementioned compounds crystallize into two different crystal systems-evidently due to the different crystallization conditions-their chemical structures are identical...
February 8, 2017: Antibiotics
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