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C M Nday, E Halevas, A Tsiaprazi-Stamou, D Eleftheriadou, A Hatzidimitriou, G Jackson, D Reid, A Salifoglou
Due to its physical and chemical properties, bismuth (Bi(III)) is widely used in the treatment of several gastrointestinal and skin diseases, and infections caused by bacteria. Herein, its known antimicrobial potential was taken into consideration in the synthesis of two new hybrid ternary materials of Bi(III) with the physiological α-hydroxycarboxylic glycolic acid and 1,10-phenanthroline (phen), [Bi2(C2H2O3)2(C2H3O3)(NO3)]n(.) nH2O (1) and [Bi(C12H8N2)(NO3)4](C10H8N4) (2), aiming at improving its antibacterial properties...
February 11, 2017: Journal of Inorganic Biochemistry
Zhenglu Li, Ting Cao, Meng Wu, Steven G Louie
Artificial lattices have been employed in a broad range of two-dimensional systems, including those with electrons, atoms and photons, in the quest for massless Dirac fermions with high flexibility and controllability. Establishing triangular or hexagonal symmetry, from periodically patterned molecule assembly or electrostatic gating as well as from moiré pattern induced by substrate, has produced electronic states with linear dispersions from two-dimensional electron gas (2DEG) residing in semiconductors, metals and graphene...
February 23, 2017: Nano Letters
Ziqi Tian, Shannon M Mahurin, Sheng Dai, De-En Jiang
Porous graphene holds great promise as a one-atom-thin, high-permeance membrane for gas separation, but to precisely control the pore size down to three to five angstroms proves challenging. Here we propose an ion-gated graphene membrane comprising a monolayer of ionic liquid coated porous graphene to dynamically modulate the pore size to achieve selective gas separation. This approach enables the otherwise non-selective large pores on the order of 1 nm in size to be selective for gases whose diameters range from three to four angstroms...
February 23, 2017: Nano Letters
Pierre Regenass, Damien Bosc, Stéphanie Riché, Patrick Gizzi, Marcel Hibert, Lydia Brelot, A Ganesan, Dominique Bonnet
Aza-diketopiperazines (Aza-DKP) represent an underprivileged motif obtained by scaffold hopping of 2,5-diketopiperazines (2,5-DKP). Herein, we compare the synthesis but also the structural and the physicochemical properties of aza-DKP 4 vs 2,5-DKP 7. Thus, X-ray and 1H NMR studies show that aza-DKP 4 is a rigid and non-flat scaffold like the 2,5-DKP 7. Moreover, the replacement of one Calpha-stereogenic center by a nitrogen atom results in a significant improvement of both the water solubility and the microsomal stability...
February 23, 2017: Journal of Organic Chemistry
Oriol Lamiel-Garcia, Kyoung Chul Ko, Jin Yong Lee, Stefan T Bromley, Francesc Illas
All electron relativistic density functional theory (DFT) based calculations using numerical atom-centered orbitals have been carried out to explore the relative stability, atomic and electronic structure of a series of stoichiometric TiO2 anatase nanoparticles explicitly containing up to 1365 atoms as a function of size and morphology. The nanoparticles under scrutiny exhibit octahedral or truncated octahedral structures and span the 1- 6 nm size range. Initial structures were obtained from a Wulff construction, thus exhibiting the most stable (101) and (001) anatase surfaces...
February 23, 2017: Journal of Chemical Theory and Computation
Jeffrey J Chalmers, Xiaoxia Jin, Andre Francis Palmer, Peter Amaya, Mark H Yazer, Lee R Moore, Kyoung-Joo Park, X Jeff Pan, Maciej Zborowski
The magnetic characteristics of hemoglobin (Hb) changes with the binding of dioxygen (O2) to the heme prosthetic groups of the globin chains: from paramagnetic ferrous Hb to diamagnetic ferrous oxyhemoglobin (oxyHb) with reversibly bound O2, or paramagnetic ferric methemoglobin (metHb). When multiplied over the number of Hb molecules in a red blood cell (RBC), the effect is detectable through motion analysis of RBCs in a high magnetic field and gradient. This motion is referred to as magnetophoretic mobility which can be conveniently expressed as a fraction of the cell sedimentation coefficient...
February 23, 2017: Analytical Chemistry
Lichao Sun, Qingfeng Zhang, Guangfang Grace Li, Esteban Villarreal, Xiaoqi Fu, Hui Wang
Kinetically controlled, seed-mediated coreduction provides a robust and versatile synthetic approach to multimetallic nanoparticles with precisely controlled geometries and compositions. Here we demonstrate that single-crystalline cylindrical Au nanorods selectively transform into a series of structurally distinct Au@Au-Pd alloy core-shell bimetallic nanorods with exotic multifaceted geometries enclosed by specific types of facets upon seed-mediated Au-Pd coreduction under diffusion controlled conditions. By adjusting several key synthetic parameters, such as the Pd/Au precursor ratio, the reducing agent concentration, the capping surfactant concentration, and foreign metal ion additives, we have been able to simultaneously fine-tailor the atomic-level surface structures and fine-tune the compositional stoichiometries of the multifaceted Au-Pd bimetallic nanorods...
February 23, 2017: ACS Nano
Meiling Xu, Sen Shao, Bo Gao, Jian Lv, Quan Li, Yanchao Wang, Hui Wang, Lijun Zhang, Yanming Ma
Titanium dioxide has been widely used as efficient transition metal oxide photocatalyst. However, its photocatalytic activity is limited to ultraviolet spectrum range due to the deficient large bandgap beyond 3 eV. Efforts towards to reduce the bandgap for achieving a broader spectrum range of light absorption are attempted with a success on the experimental synthesis of dopant-free metastable surface structure of rutile-type TiO2 (011) 21. This new surface phase possesses a much reduced bandgap of ~2.1 eV, showing a great potential for an excellent photocatalyst covering a wide range of visible light...
February 23, 2017: ACS Applied Materials & Interfaces
Maryam Yousaf, Huan Huang, Ping Li, Chen Wang, Yanlian Yang
Fibrillar deposits of the human islet amyloid polypeptide (hIAPP) is considered as a root of Type II diabetes mellitus. Fluorinated graphene quantum dots (FGQDs) are new carbon nanomaterials with unique physicochemical properties containing highly electronegative F atoms. Herein we report a single step synthesis method of FGQDs with an inhibitory effect on aggregation and cytotoxicity of hIAPP in vitro. Highly fluorescent and water dispersible FGQDs, less than 3 nm in size were synthesized by the microwave-assisted hydrothermal method...
February 23, 2017: ACS Chemical Neuroscience
Dehua Xiong, Qingqing Zhang, Wei Li, Junjie Li, Xiuli Fu, M F Cerqueira, Pedro Alpuim, Lifeng Liu
Ultrafine molybdenum sulfide (MoS2) nanocrystals are grown on a porous cobalt (Co) foam current collector by atomic layer deposition (ALD) using molybdenum hexacarbonyl and hydrogen sulfide as precursors. When used to catalyze the oxygen evolution reaction (OER), the optimal Co@MoS2 electrode, even with a MoS2 loading as small as 0.06 mg cm(-2), exhibits a large cathodic shift of ca. 200 mV in the onset potential (the potential at which the current density is 5 mA cm(-2)), a low overpotential of only 270 mV to attain an anodic current density of 10 mA cm(-2), much smaller charge transfer resistance and substantially improved long-term stability at both low and high current densities, with respect to the bare Co foam electrode, showing substantial promise for use as an efficient, low-cost and durable anode in water electrolyzers...
February 23, 2017: Nanoscale
Dejiong Zhang, Chuanhong Jin, He Tian, Yalin Xiong, Hui Zhang, Peisheng Qiao, Jie Fan, Ze Zhang, Z Y Li, Jixue Li
The surface oxidation of palladium nanocrystals plays an important role in changing the active sites and subsequently influencing the catalytic reactivity. Such a microscopy study on surface oxidation, down to the atomic scale, is essential for understanding the structure-property correlations of palladium nanocrystal based catalysts. Herein, we present an in situ atomic scale study on the surface oxidation behavior of palladium nanocrystals, which is induced by electron beam irradiation under low oxygen partial pressure and at room temperature inside an environmental transmission electron microscope...
February 23, 2017: Nanoscale
Sean R Tachibana, Longteng Tang, Yanli Wang, Liangdong Zhu, Weimin Liu, Chong Fang
Fluorescent protein biosensors are popular reporters for biological processes and life sciences, but their fundamental working mechanisms remain unclear. To characterize the functional fluorescence events on their native timescales, we implemented wavelength-tunable femtosecond stimulated Raman spectroscopy (FSRS) to shed light on a blue-green emission-ratiometric fluorescent protein based Ca(2+) biosensor with a single Pro377Arg mutation. The transient Raman modes of the embedded chromophore from ca. 1000-1650 cm(-1) exhibit characteristic intensity and frequency dynamics which infer the underlying atomic motions and photochemical reaction stages...
February 23, 2017: Physical Chemistry Chemical Physics: PCCP
S V Andreychenko, A V Klepko, L V Gorban, O A Motryna, L V Grubska, O V Trofimenko
AIM: The research was aimed on analysis of the remote consequences of Chornobyl accident on the reproductive function of men adult residing in Ukraine. MATERIALS AND METHODS: 232 male volunteers with mean age of 34 years (range 20-47) from 5 different regions of Ukraine (Zhytomyr, Ivano-Frankivsk, Kyiv, Poltava, and Kyiv city) were enrolled in cross-sectional studies of long term radiation effects on seminal plasma and sperm. All manipulations, analysis and classification of ejaculates were done accordingly to WHO recommendations...
December 2016: Experimental Oncology
Stephanie Oerum, Clément Dégut, Pierre Barraud, Carine Tisné
To date, about 90 post-transcriptional modifications have been reported in tRNA expanding their chemical and functional diversity. Methylation is the most frequent post-transcriptional tRNA modification that can occur on almost all nitrogen sites of the nucleobases, on the C5 atom of pyrimidines, on the C2 and C8 atoms of adenosine and, additionally, on the oxygen of the ribose 2'-OH. The methylation on the N1 atom of adenosine to form 1-methyladenosine (m1A) has been identified at nucleotide position 9, 14, 22, 57, and 58 in different tRNAs...
February 21, 2017: Biomolecules
Matija Uršič, Tanja Lipec, Anton Meden, Iztok Turel
Four novel ruthenium organometallic complexes: [(η⁶-p-cymene)Ru(4,4,4-trifluoro-1-(4-bromophenyl)-1,3-butanedione)Cl] (1), [(η⁶-p-cymene)Ru(4,4,4-trifluoro-1-(4-bromophenyl)-1,3-butanedione)pta]PF₆ (2), [(η⁶-p-cymene)Ru(4,4,4-trifluoro-1-(4-iodophenyl)-1,3-butanedione)Cl] (3) and [(η⁶-p-cymene)Ru(4,4,4-trifluoro-1-(4-iodophenyl)-1,3-butanedione)pta]PF₆ (4) were synthesized and characterized by elemental analysis, infrared (IR), UV-Vis, NMR and mass spectroscopy and single-crystal X-ray diffraction...
February 20, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Max Medina-Ramírez, Rogier W Sanders, Quentin J Sattentau
PURPOSE OF REVIEW: To provide an update on the latest developments in the field of HIV-1 antibody-based soluble envelope glycoprotein (Env) trimer design for vaccine use. RECENT FINDINGS: The development of soluble native-like HIV-1 Env trimer immunogens has moved the field of antibody-based vaccine design forward dramatically over the past few years with refinement of various stabilizing approaches. However, despite this progress, significant challenges remain...
February 21, 2017: Current Opinion in HIV and AIDS
Keka R Chakraborty, Barnita Paul, Rakesh Shukla, Psr Krishna, Amit Kumar, Mayuresh Mukadam, Balaji Mandal, Anushree Roy, Avesh Tyagi, S Yusuf
The structural and magnetic properties of the Y1-xTbxMnO3(0.1x0.3)compoundswere investigated.Neutron diffraction patterns for all three samples,recorded at room temperature (RT),were fitted to the nuclear structure confirming the paramagnetic nature of the compounds. At 2.8 K,for the x = 0.1 sample magnetic moments of the Tb3+ionic as well as Mn3+ionic were ordered.At 5 K for the x = 0.2 sample only the Mn3+ionic magnetic moments were ordered. Therewere six sites for Mn atoms. Three on the z = 0 plane and three on the z = 0...
February 23, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Wei Shi, Haitao Zhao, Bingan Lu
In this paper, ZnCo2O4 nanowall arrays were firstly obtained through self-assembly followed by calcination. Then atomic layer deposition was used to fabricate core-shell ZnCo2O4@TiO2 nanowall arrays (NWAs) as anode materials for lithium ion batteries (LIBs). The hierarchical nanowall array nanostructure with fast ion diffusion and electron transport at electrode/electrolyte interface, while the shell of TiO2 with excellent chemical stability can protect the ZnCo2O4 nanowall arrays from volume expansion during charge and discharge processes...
February 23, 2017: Nanotechnology
Soroosh Sharifi-Asl, Fernando A Soto, Anmin Nie, Yifei Yuan, Hasti Asayesh-Ardakani, Tara Foroozan, Vitaliy Yurkiv, Boao Song, Farzad Mashayek, Robert F Klie, Khalil Amine, Jun Lu, Perla B Balbuena, Reza Shahbazian-Yassar
Thermal runaways triggered by the oxygen release from oxide cathode materials pose a major safety concern for widespread application of lithium ion batteries. Utilizing in-situ aberration-corrected scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) at high temperatures, we show that oxygen release from LixCoO2 cathode crystals is occurring at the surface of particles. We correlated this local oxygen evolution from the LixCoO2 structure with local phase transitions spanning from layered to spinel and then to rock salt structure upon exposure to elevated temperatures...
February 23, 2017: Nano Letters
Thomas W Hayes, Iain H Moal
Many proteins can adopt multiple distinct conformational states which often play different functional roles. Previous studies have shown that the underlying global dynamics through which these states are accessed are, at least in part, encoded by the protein's topology. In this work we present a method for generating transition pathways between states by perturbing the protein towards a target conformational state along thermally accessible collective motions calculated from the starting conformation. Specifically, the least absolute shrinkage and selection operator (LASSO) is used to identify the most parsimonious route along soft modes calculated using the anisotropic network model...
February 23, 2017: Journal of Chemical Theory and Computation
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