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Sarah Keller, Alessandro Prescimone, Edwin C Constable, Catherine E Housecroft
The heteroleptic complexes [Cu(tBu-xantphos)(bpy)][PF6 ] and [Ag(tBu-xantphos)(bpy)][PF6 ], where tBu-xantphos = 9,9-dimethyl-4,5-bis(di-tert-butylphosphino)xanthene and bpy = 2,2'-bipyridine have been synthesized and their photophysical properties investigated. Single crystal X-ray diffraction studies of the compounds under ambient and increased pressure are presented; increase in pressure results in little structural perturbation. For the copper(i) complexes, the effects of changing the N^N ligand from bpy to 6-methyl-2,2'-bipyridine (6-Mebpy), 6-bromo-2,2'-bipyridine (6-Brbpy), and 4,4'-di(tert-butyl)-2,2'-bipyridine (4,4'-tBu2 bpy) were also investigated...
February 19, 2018: Photochemical & Photobiological Sciences
Xiangdong Guo, Hai Hu, Baoxin Liao, Xing Zhu, Xiaoxia Yang, Qing Dai
Graphene plasmon with extremely strong light confinement and tunable resonance
 frequency represents a promising surface-enhanced infrared absorption (SEIRA) sensing platform.
 However, plasmonic absorption is relatively weak (approximately 1%~9%) in monolayer
 graphene nanostructures, which would limit it sensitivity. Here, we theoretically propose a hybrid
 plasmon-metamaterial structure that can realize perfect absorption in graphene with a low carrier
 mobility of 1000 cm<sup>2</sup>/Vs...
February 19, 2018: Nanotechnology
Mousumi Barik, Anjali Rawani, Subrata Laskar, Goutam Chandra
The larvicidal potentiality of crude and ethyl acetate extracts of fruits of Acacia auriculiformis was investigated against all the larval instars of JE vector Culex vishnui. The crude extracts showed good results against all the larval instars with highest mortality at 0.09%. Highest mortality was found at 300 ppm of ethyl acetate extract. Lowest LC50 value was obtained at 72 h for third instar larvae. Non target organisms tested, showed no to very less mortality to ethyl acetate solvent extract. Presence of N-H stretching, a C=O stretching, C=C and C-N stretching vibrations of secondary amide or amine group were confirmed from IR analysis...
February 19, 2018: Natural Product Research
Haixiang He, Weimin Zhu, Wenli Su, Lihui Dong, Bin Li
The H+ + H2 reaction and its isotopic variants as the simplest triatomic ion-molecule reactive system have been attracting much interests, however there are few studies on the titled reaction at state-to-state level until recent years. In this work, accurate state-to-state quantum dynamics studies of the titled reaction have been carried out by a reactant Jacobi coordinate-based time-dependent wave packet approach on diabatic potential energy surfaces constructed by Kamisaka et al. Product ro-vibrational state-resolved information has been calculated for collision energies up to 0...
February 19, 2018: Journal of Physical Chemistry. A
Agata Motyka, Anna Dzimitrowicz, Piotr Jamroz, Ewa Lojkowska, Wojciech Sledz, Pawel Pohl
Diseases caused by phytopathogenic bacteria are responsible for significant economic losses, and these bacteria spread through diverse pathways including waterways and industrial wastes. It is therefore of interest to develop potent methods for their eradication. Here, antibacterial properties of direct current atmospheric pressure glow discharge (dc-APGD) generated in contact with flowing bacterial suspensions were examined against five species of phytopathogens. Complete eradication of Clavibacter michiganensis subsp...
February 19, 2018: Biotechnology and Bioengineering
Binbin Zhou, Mei Mao, Xiaomin Cao, Meihong Ge, Xianghu Tang, Shaofei Li, Dongyue Lin, LiangBao Yang, Jinhuai Liu
Surface enhanced Raman spectroscopy (SERS) is a powerful spectroscopic technique with unique vibrational fingerprints, making it an ideal candidate for in situ multiphase detection. However, it is a great challenges that how to guide the SERS sensor to targets molecule of interest in multiphase heterogeneous samples with minimally disturbance. Here, we present a portable ultrasensitive and highly repeatable SERS sensor for in situ multiphase detection. The sensor is composed of com-mercial Ag acupuncture needle and PVP-Au nanoparticles (Au NPs)...
February 19, 2018: Analytical Chemistry
Hui Jiang, Peng Hu, Jun Ye, Apoorva Chaturvedi, Keke K Zhang, Yongxin Li, Yi Long, Denis Fichou, Christian Kloc, Wenping Hu
Four five fused-ring isomers were rationally designed and synthesized to investigate the isomeric influence of linear and angular shapes in affecting their molecular packing and resultant electronic properties. Single-crystal field-effect transistors showed mobility order of 5,7-ICZ (3.61 cm2 V-1 s-1) > 5,11-ICZ (0.55 cm2 V-1 s-1) > 5,12-ICZ (~10-5 cm2 V-1 s-1) and 11,12-ICZ (~10-6 cm2 V-1 s-1). Theoretical calculations based on density functional theory (DFT) and polaron transport model revealed that 5, 7-ICZ can reach higher mobilities than the others thanks to relatively higher hole transfer integral that links to stronger intermolecular interaction due to the presence of multiple NH···pi and CH···pi(py) interactions with energy close to common NH···N hydrogen bonds, as well as overall lower hole-vibrational coupling owing to the absence of coupling of holes to low frequency modes due to better pi conjugation...
February 18, 2018: Angewandte Chemie
Jiuchuang Yuan, Di He, Shufen Wang, Maodu Chen, Keli Han
The global diabatic potential energy surfaces (PESs) of the MgH2 + system, which can be used to study the dynamics of the Mg+ (3p2 P) + H2 (X1 Σ) → MgH+ (X1 Σ+ ) + H(2 S) reaction, are structured for the first time. The diabatic PESs are correlated with the ground state 12 A' and the first excited state 22 A'. The multi-reference configuration interaction method and the VQZ basis set are used in ab initio calculations, and diabatic potential energies are calculated based on the molecular properties of the dipole moment...
February 19, 2018: Physical Chemistry Chemical Physics: PCCP
María Mar Quesada-Moreno, Albert Virgili, Eva Monteagudo, Rosa M Claramunt, Juan Ramón Avilés-Moreno, Juan Jesús López-González, Ibon Alkorta, José Elguero
For the first time, the success of a methodology for the determination of enantiomeric excess (% ee) in chiral solid samples by vibrational circular dichroism (VCD) spectroscopy is reported. We have used camphor to determine the % ee in a blind sample constituted by a mixture of its two enantiomers as a test for the validity of our approach. IR and VCD spectra of different enantiomeric mixtures of R/S-camphor in Nujol mulls were recorded and linear regressions of VCD intensities (ΔAbs.) vs. % ee for selected bands were found...
February 19, 2018: Analyst
Xin Ning, Heling Wang, Xinge Yu, Julio A N T Soares, Zheng Yan, Kewang Nan, Gabriel Velarde, Yeguang Xue, Rujie Sun, Qiyi Dong, Haiwen Luan, Chan Mi Lee, Aditya Chempakasseril, Mengdi Han, Yiqi Wang, Luming Li, Yonggang Huang, Yihui Zhang, John Rogers
Microelectromechanical systems remain an area of significant interest in fundamental and applied research due to their wide ranging applications. Most device designs, however, are largely two-dimensional and constrained to only a few simple geometries. Achieving tunable resonant frequencies or broad operational bandwidths requires complex components and/or fabrication processes. The work presented here reports unusual classes of three-dimensional (3D) micromechanical systems in the form of vibratory platforms assembled by controlled compressive buckling...
April 11, 2017: Advanced Functional Materials
Dongkeun Park, Juan Bascuñán, Philip C Michael, Yukikazu Iwasa
In this paper we present two design options for a tabletop liquid-helium-free, persistent-mode 1.5-T/90-mm MgB2 "finger" MRI magnet for osteoporosis screening. Both designs, one with and the other without an iron yoke, satisfy the following criteria: 1) 1.5-T center field with a 90-mm room-temperature bore for a finger to be placed at the magnet center; 2) spatial field homogeneity of <5 ppm over a 20-mm diameter of spherical volume (DSV); 3) persistent-mode operation with temporal stability of <0...
April 2018: IEEE Transactions on Applied Superconductivity: a Publication of the IEEE Superconductivity Committee
Silvia Convento, Md Shoaibur Rahman, Jeffrey M Yau
Sensory cortical systems often activate in parallel, even when stimulation is experienced through a single sensory modality [1-3]. Co-activations may reflect the interactive coupling between information-linked cortical systems or merely parallel but independent sensory processing. We report causal evidence consistent with the hypothesis that human somatosensory cortex (S1), which co-activates with auditory cortex during the processing of vibrations and textures [4-9], interactively couples to cortical systems that support auditory perception...
February 1, 2018: Current Biology: CB
Subhojyoti Chatterjee, Seth Olsen, Ewan W Blanch, Feng Wang
Resveratrol (RSVL) is a stilbenoid phytoalexin with promised myriad health benefits predominantly attributed to the trans (E) diastereomeric form. A recent study has implicated the Z (cis) diastereomer in human health. This stereoisomer binds with high affinity to human tyrosyl-tRNA synthetase, initiating a downstream cascade that promotes the expression of genes associated with the cellular stress response. We discovered that the non-planar structure of cis-resveratrol conformer possesses certain chiral signals in its simulated vibrational circular dichroism (VCD) and Raman optical activity (ROA) spectra...
February 17, 2018: Journal of Physical Chemistry. B
Yan-Jie Gu, Min-Liang Zhu, Yan-Li Li, Chun-Hua Xiong
A new type of magnetic metal chelating carrier (PCMM-IDA-Cu2+ ) was prepared for the immobilization of papain, using chitosan as raw material, nano Fe3 O4 as magnetic material, SiO2 as porogen, iminodiacetic acid (IDA) as a chelating ligand, and binding with transition metal ion (Cu2+ ). The resulting products were well characterized by optical microscopy, scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA)...
February 15, 2018: International Journal of Biological Macromolecules
Ana Olivera, Michael A Beaven, Dean D Metcalfe
FcεRI is the primary receptor in mast cells that mediate allergic reactions by inducing rapid release of mediators, an adaptive immune response that may have evolved as a host defense against parasites and venoms. Yet, it is apparent that mast cells are also activated via non-IgE receptors whose significance is just beginning to be understood. This includes the Mas-related GPCRs (MRGPRX2) that may contribute to reactions to diverse antimicrobials and polybasic compounds, and ADGRE2, an adhesion GPCR which is activated by mechanical vibration and whose variants are associated with familial vibratory urticaria...
February 15, 2018: Journal of Allergy and Clinical Immunology
Margaret Aron, Thomas G Landry, Manohar Bance
BACKGROUND: Total ossicular replacement prostheses (TORP) are often used to re-establish ossicular coupling of sound in an ear lacking a stapes supra-structure. The use of TORPs, however, is associated with a 2/3 five year failure rate due to their anatomic instability over time in the middle ear. The use of autologous fat to try and stabilize TORPs may improve long-term results with this challenging ossicular reconstruction technique. METHODS: A cadaveric temporal bone model was developed and laser Doppler vibrometry was used to measure and record round window membrane vibration in response to sound stimulation under the following conditions: normal middle ear, middle ear filled with fat, normal middle ear with TORP prosthesis, TORP prosthesis with fat around its distal end and TORP prosthesis with fat filling the middle ear...
February 17, 2018: Journal of Otolaryngology—Head & Neck Surgery
Chih-Hao Chin, Meng-Yeh Lin, Tzu-Ping Huang, Yu-Jong Wu
Electron bombardment during deposition of an Ar matrix containing a small proportion of allene generated allene cations. Further irradiation of the matrix sample at 385 nm destroyed the allene cations and formed propyne cations in solid Ar. Both cations were identified according to previously reported IR absorption bands. Using a similar technique, we recorded the ultraviolet absorption spectrum of allene cations in solid Ar. The vibrationally resolved progression recorded in the range of 266-237 nm with intervals of about 800 cm -1 was assigned to the A 2 E ← X 2 E transition of allene cations, and the broad continuum absorption recorded in the region of 229-214 nm was assigned to their B 2 A 1 ← X 2 E transition...
February 8, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Arathi P J, Bhaskar Seemesh, Rajendra Kumar Reddy G, Suresh Kumar P, Ramanathan V
Different nano-structures of noble metals have been the conventional substrates for carrying out Surface Enhanced Raman Spectroscopy (SERS). In this paper we examine electrodeposited copper (Cu) nano-structures on pencil graphite as novel substrate to carry out SERS measurements by considering l-cystine (Cys-Cys) (dimer of the amino acid cysteine) as the probe. The formation of monolayer of the probe molecule on the substrates was confirmed using cyclic voltammetric measurements. Mode of adsorption of Cys-Cys was observed to be different on bulk Cu (taken in the wire form) and nano-structured Cu on pencil graphite...
February 5, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Sahadevan Neethu, Sebastian Jose Midhun, M A Sunil, Soman Soumya, E K Radhakrishnan, Mathew Jyothis
The green synthesis of silver nanoparticles (AgNPs) using biological systems such as fungi has evolved to become an important area of nanobiotechnology. Herein, we report for the first time the light-induced extracellular synthesis of silver nanoparticles using algicolous endophytic fungus Penicillium polonicum ARA 10, isolated from the marine green alga Chetomorpha antennina. Parametric optimization, including the concentration of AgNO 3 , fungal biomass, ratio of cell filtrate and AgNO 3 , pH, reaction time and presence of light, was done for rapid AgNPs production...
February 7, 2018: Journal of Photochemistry and Photobiology. B, Biology
Xiaowei Li, Hiro Minamimoto, Kei Murakoshi
The vibrational characteristics of ligand-capped lead sulfide (PbS) quantum dots (QDs) were clarified via electrochemical surface-enhanced Raman spectroscopy (EC-SERS) using a hybridized system of gold (Au) nanodimers and PbS QDs under electrochemical potential control. Enhanced electromagnetic field caused by the coupling of QDs with plasmonic Au nanodimers allowed the characteristic behavior of the ligand oleic acid (OA) on the PbS QD surface to be detected under electrochemical potential control. Binding modes between the QDs and OA molecules were characterized using synchronous two-dimensional correlation spectra at distinct electrochemical potentials, confirming that the bidentate bridging mode was probably the most stable mode even under relatively negative potential polarization...
February 7, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
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