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Natalia D Andersen, Paula V Monje
Adult Schwann cell (SC) cultures are usually derived from nerves subjected to a lengthy step of pre-degeneration to facilitate enzymatic digestion and recovery of viable cells. To overcome the need for pre-degeneration, we developed a method that allows the isolation of adult rat sciatic nerve SCs immediately after tissue harvesting. This method combines the advantages of implementing a rapid enzymatic dissociation of the nerve fibers and a straightforward separation of cells versus myelin that improves both cell yield and viability...
2018: Methods in Molecular Biology
Takashi Kumagai, Janina N Ladenthin, Yair Litman, Mariana Rossi, Leonhard Grill, Sylwester Gawinkowski, Jacek Waluk, Mats Persson
Tautomerization in single porphycene molecules is investigated on Cu(111), Ag(111), and Au(111) surfaces by a combination of low-temperature scanning tunneling microscopy (STM) experiments and density functional theory (DFT) calculations. It is revealed that the trans configuration is the thermodynamically stable form of porphycene on Cu(111) and Ag(111), whereas the cis configuration occurs as a meta-stable form. The trans → cis or cis → trans conversion on Cu(111) can be induced in an unidirectional fashion by injecting tunneling electrons from the STM tip or heating the surface, respectively...
March 14, 2018: Journal of Chemical Physics
Yexin Feng, Zhichang Wang, Jing Guo, Ji Chen, En-Ge Wang, Ying Jiang, Xin-Zheng Li
Proton tunneling is an elementary process in the dynamics of hydrogen-bonded systems. Collective tunneling is known to exist for a long time. Atomistic investigations of this mechanism in realistic systems, however, are scarce. Using a combination of ab initio theoretical and high-resolution experimental methods, we investigate the role played by the protons on the chirality switching of a water tetramer on NaCl(001). Our scanning tunneling spectroscopies show that partial deuteration of the H2 O tetramer with only one D2 O leads to a significant suppression of the chirality switching rate at a cryogenic temperature (T), indicating that the chirality switches by tunneling in a concerted manner...
March 14, 2018: Journal of Chemical Physics
Neelam Khanal, Chiara Masellis, Michael Z Kamrath, David E Clemmer, Thomas R Rizzo
We report here our combination of cryogenic, messenger-tagging, infrared (IR) spectroscopy with ion mobility spectrometry (IMS) and mass spectrometry (MS) as a way to identify and analyze a set of human milk oligosaccharides (HMOs) ranging from trisaccharides to hexasaccharides. The added dimension of IR spectroscopy provides a diagnostic fingerprint in the OH and NH stretching region, which is crucial to identify these oligosaccharides, which are difficult to distinguish by IMS alone. These results extend our previous work in demonstrating the generality of this combined approach for distinguishing subtly different structural and regioisomers of glycans of biologically relevant size...
March 15, 2018: Analyst
Minae Watanabe, Jun Ueyama, Eiji Ueno, Yuko Ueda, Masaya Oda, Yuko Umemura, Takashi Tanahashi, Yoshitomo Ikai, Isao Saito
Dinotefuran is an insecticide belonging to the neonicotinoid class, which is frequently used to control pests in paddy rice owing to its permeability and effectiveness against sucking insects. Since 2002, this insecticide has been commercially available in Japan, and has become controversial due to its high detection frequency in brown rice for primary consumption. In this study, the effects of processing and cooking on the reduction of dinotefuran residues in commercially available brown rice were investigated...
March 13, 2018: Food Additives & Contaminants. Part A, Chemistry, Analysis, Control, Exposure & Risk Assessment
Josep Saurí, Wolfgang Bermel, Teodor Parella, R Thomas Williamson, Gary E Martin
1,n-ADEQUATE is a powerful NMR technique for elucidating the structure of proton-deficient small molecules that can help to establish the carbon skeleton of a given molecule by providing long-range three-bond13 C-13 C correlations. Care must be taken when using the experiment to identify the simultaneous presence of one-bond13 C-13 C correlations that are not filtered out, unlike the HMBC experiment that has a low-pass J-filter to filter1 JCH responses out. Dual-optimized, inverted1 JCC 1,n-ADEQUATE is an improved variant of the experiment that affords broadband inversion of direct responses, obviating the need to take additional steps to identify these correlations...
March 13, 2018: Magnetic Resonance in Chemistry: MRC
Han Chi, Kristian A Dehne, Cory M Baumgarten, Hanchen Wang, Liang Yin, Brendan A Reagan, Jorge J Rocca
Heat generation is a key obstacle to scaling high energy solid-state lasers to the multi-kilowatt average powers required for several key applications. We demonstrate an accurate, in situ, noninvasive optical technique to that makes three-dimensional (3-D) temperature maps within cryogenic amplifiers operating at high average power. The temperature is determined by analyzing the fluorescence spectra with a neural network function. The accuracy of the technique relies on a calibration that does not depend on simulations...
March 5, 2018: Optics Express
Trixi von Schlippenbach, Peter J Oefner, Wolfram Gronwald
Non-uniform sampling (NUS) allows the accelerated acquisition of multidimensional NMR spectra. The aim of this contribution was the systematic evaluation of the impact of various quantitative NUS parameters on the accuracy and precision of 2D NMR measurements of urinary metabolites. Urine aliquots spiked with varying concentrations (15.6-500.0 µM) of tryptophan, tyrosine, glutamine, glutamic acid, lactic acid, and threonine, which can only be resolved fully by 2D NMR, were used to assess the influence of the sampling scheme, reconstruction algorithm, amount of omitted data points, and seed value on the quantitative performance of NUS in1 H,1 H-TOCSY and1 H,1 H-COSY45 NMR spectroscopy...
March 9, 2018: Scientific Reports
Matthew A Zambrello, Adam D Schuyler, Mark W Maciejewski, Frank Delaglio, Irina Bezsonova, Jeffrey C Hoch
The development of multidimensional NMR spectroscopy enabled an explosion of structural and dynamical investigations on proteins and other biomacromolecules. Practical limitations on data sampling, based on the Jeener paradigm of parametric sampling of indirect time domains, have long placed limits on resolution in the corresponding frequency dimensions. The emergence of nonuniform sampling (NUS) in indirect time dimensions circumvents those limitations, affording high resolution spectra from short data records collected in practically realized measurement times...
March 6, 2018: Methods: a Companion to Methods in Enzymology
Hazuki Yonashiro, Kenjirou Higashi, Chikako Morikawa, Keisuke Ueda, Tsutomu Itoh, Masataka Ito, Hyuma Masu, Shuji Noguchi, Kunikazu Moribe
The morphology and stability of amorphous nanoparticles of glibenclamide (GLB) prepared by the antisolvent method using different methods of adding hypromellose (HPMC) were evaluated. Nano-A was prepared by the injection of a dimethyl sulfoxide (DMSO) solution of GLB into the HPMC solution, whereas nano-B was obtained by the injection of a DMSO solution of GLB and HPMC into water. Cryogenic transmission electron microscopy, field-emission scanning electron microscopy, and field-emission transmission electron microscopy including energy dispersive X-ray spectrometry revealed that the particles of the nano-A and nano-B samples are hollow spheres and non-spherical nanoparticles, respectively...
March 5, 2018: Molecular Pharmaceutics
Adam P Cismesia, Matthew R Bell, Larry F Tesler, Melanie Alves, Nicolas C Polfer
Vibrational ion spectroscopy techniques coupled with mass spectrometry are applied to standard metabolites as a proof-of-principle demonstration for the structural identification of unknown metabolites. The traditional room temperature infrared multiple photon dissociation (IRMPD) spectroscopy technique is shown to differentiate chemical moieties in isobaric and isomeric variants. These results are compared to infrared spectra of cryogenically cooled analyte ions, showing enhanced spectral resolution, and thus also improved differentiation between closely related molecules, such as isomers...
March 2, 2018: Analyst
V F Mitin, V V Kholevchuk, A V Semenov, A A Kozlovskii, N S Boltovets, V A Krivutsa, A S Slepova, S V Novitskii
We developed a heat-sensitive material based on nanocrystalline SiC films obtained by direct deposition of carbon and silicon ions onto sapphire substrates. These SiC films can be used for resistance thermometers operating in the 2 K-300 K temperature range. Having high heat sensitivity, they are relatively low sensitive to the magnetic field. The designs of the sensors are presented together with a discussion of their thermometric characteristics and sensitivity to magnetic fields.
February 2018: Review of Scientific Instruments
U Zastrau, C Rödel, M Nakatsutsumi, T Feigl, K Appel, B Chen, T Döppner, T Fennel, T Fiedler, L B Fletcher, E Förster, E Gamboa, D O Gericke, S Göde, C Grote-Fortmann, V Hilbert, L Kazak, T Laarmann, H J Lee, P Mabey, F Martinez, K-H Meiwes-Broer, H Pauer, M Perske, A Przystawik, S Roling, S Skruszewicz, M Shihab, J Tiggesbäumker, S Toleikis, M Wünsche, H Zacharias, S H Glenzer, G Gregori
We present an extreme ultraviolet (EUV) microscope using a Schwarzschild objective which is optimized for single-shot sub-micrometer imaging of laser-plasma targets. The microscope has been designed and constructed for imaging the scattering from an EUV-heated solid-density hydrogen jet. Imaging of a cryogenic hydrogen target was demonstrated using single pulses of the free-electron laser in Hamburg (FLASH) free-electron laser at a wavelength of 13.5 nm. In a single exposure, we observe a hydrogen jet with ice fragments with a spatial resolution in the sub-micrometer range...
February 2018: Review of Scientific Instruments
Daniel P Engelhart, James Patton, Elena Plis, Russell Cooper, Ryan Hoffmann, Dale Ferguson, Robert V Hilmer, John McGarity, Ernest Holeman
The Mumbo space environment simulation chamber discussed here comprises a set of tools to calibrate a variety of low flux, low energy electron and ion detectors used in satellite-mounted particle sensors. The chamber features electron and ion beam sources, a Lyman-alpha ultraviolet lamp, a gimbal table sensor mounting system, cryogenic sample mount and chamber shroud, and beam characterization hardware and software. The design of the electron and ion sources presented here offers a number of unique capabilities for space weather sensor calibration...
February 2018: Review of Scientific Instruments
Alexander Sheldrick, David Müller, Alan Günther, Pablo Nieto, Otto Dopfer
The optical properties of flavins strongly depend on the charge and oxidation states as well as the environment. Herein, the electronic spectrum of cold protonated lumichrome, the smallest flavin molecule, is recorded by means of photodissociation in the visible range (VISPD) in a cryogenic ion trap tandem mass spectrometer coupled to an electrospray ionization source. The vibronic spectrum is assigned to the S1 ← S0 (ππ*) transition of the most stable N5-protonated isomer by comparison with quantum chemical calculations at the PBE0/cc-pVDZ level in combination with multidimensional Franck-Condon simulations...
March 1, 2018: Physical Chemistry Chemical Physics: PCCP
Lorenzo I Finci, Xiaofeng Zhang, Xiuliang Huang, Qiang Zhou, Jennifer Tsai, Teng Teng, Anant Agrawal, Betty Chan, Sean Irwin, Craig Karr, Andrew Cook, Ping Zhu, Dominic Reynolds, Peter G Smith, Peter Fekkes, Silvia Buonamici, Nicholas A Larsen
Somatic mutations in spliceosome proteins lead to dysregulated RNA splicing and are observed in a variety of cancers. These genetic aberrations may offer a potential intervention point for targeted therapeutics. SF3B1, part of the U2 small nuclear RNP (snRNP), is targeted by splicing modulators, including E7107, the first to enter clinical trials, and, more recently, H3B-8800. Modulating splicing represents a first-in-class opportunity in drug discovery, and elucidating the structural basis for the mode of action opens up new possibilities for structure-based drug design...
February 1, 2018: Genes & Development
Timothy P Lodge, Amanda L Maxwell, Joseph R Lott, Peter W Schmidt, John W McAllister, Svetlana Morozova, Frank S Bates, Yongfu Li, Robert L Sammler
The thermoresponsive behavior of a hydroxypropylmethylcellulose (HPMC) sample in aqueous solutions has been studied by a powerful combination of characterization tools, including rheology, turbidimetry, cryogenic transmission electron microscopy (cryoTEM), light scattering, small-angle neutron scattering (SANS), and small-angle X-ray scattering (SAXS). Consistent with prior literature, solutions with concentrations ranging from 0.3 to 3 wt % exhibit a sharp drop in the dynamic viscoelastic moduli G' and G″ upon heating near 57 °C...
February 28, 2018: Biomacromolecules
Suk In Park, Oliver Joe Trojak, Eunhye Lee, Jin Dong Song, Jihoon Kyhm, Ilki Han, Jong Su Kim, Gyuchul Yi, Luca Sapienza
We report on the growth and optical characterisation of droplet GaAs quantum dots with extremely-thin (11 nm) capping layers. To achieve such result, an internal thermal heating step is introduced during the growth and its role in the morphological properties of the quantum dots obtained is investigated via scanning electron and atomic force microscopy. Photoluminescence measurements at cryogenic temperatures show optically stable, sharp and bright emission from single quantum dots, at near-infrared wavelengths...
February 28, 2018: Nanotechnology
Joanna Szafraniec, Agata Antosik, Justyna Knapik-Kowalczuk, Krzysztof Chmiel, Mateusz Kurek, Karolina Gawlak, Marian Paluch, Renata Jachowicz
The anticancer drug bicalutamide was co-milled with either Macrogol6000 or Poloxamer407, and the physicochemical parameters that drive the phase transition of binary systems and influence the dissolution modification of bicalutamide were studied. Milled binary systems with reduced particle size were assessed by scanning electron microscopy and laser diffraction measurements. The results of thermal analysis supported by X-ray diffractometry confirmed the reduction of the crystallinity of bicalutamide co-milled with Macrogol6000...
February 23, 2018: International Journal of Pharmaceutics
B E Louie, W Hofstetter, G Triadafilopoulos, B L Weusten
Current ablation devices for dysplastic Barrett's esophagus are effective but have significant limitations. This pilot study aims to evaluate the safety, feasibility, and dose response of a novel cryoballoon swipe ablation system (CbSAS) in three experimental in vitro and in vivo models. CbSAS is a through-the-scope compliant balloon that is simultaneously inflated and cooled by liquid nitrous oxide delivered from a disposable handheld unit. When the cryogen is applied through a special diffuser it covers a 90° section of the circumference of the esophagus for 3 cm length...
February 21, 2018: Diseases of the Esophagus: Official Journal of the International Society for Diseases of the Esophagus
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