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https://www.readbyqxmd.com/read/27931687/l-form-transformation-phenomenon-in-mycobacterium-tuberculosis-associated-with-drug-tolerance-to-ethambutol
#1
Georgi Slavchev, Lilia Michailova, Nadya Markova
OBJECTIVE/BACKGROUND: Cell wall-deficient bacterial forms (L-forms) may occur along with resistance to factors that trigger their appearance. It is of interest to study the relationship between the L-form transformation of Mycobacterium tuberculosis and the exhibition of drug tolerance to ethambutol (EMB), an inhibitor of cell wall synthesis. METHODS: L-form variant was produced from a sensitive EMB strain of M. tuberculosis through a cryogenic stress treatment protocol and was subsequently cultivated in Middlebrook 7H9 semisolid medium, containing EMB in a minimal inhibitory concentration of 2mg/L...
December 2016: International Journal of Mycobacteriology
https://www.readbyqxmd.com/read/27926829/caught-on-camera-intermediates-of-ribosome-recycling
#2
Clarence Ling, Dmitri N Ermolenko
Following termination of protein synthesis, bacterial ribosomes are split into subunits by the joint action of elongation factor G and ribosome recycling factor in the process called ribosome recycling. In this issue of Structure, Fu et al. (2016) describe visualization of transient intermediates of ribosome recycling using time-resolved cryogenic electron microscopy.
December 6, 2016: Structure
https://www.readbyqxmd.com/read/27925011/post-harvest-embryo-development-in-ginseng-seeds-increases-desiccation-sensitivity-and-narrows-the-hydration-window-for-cryopreservation
#3
E Han, E Popova, G Cho, S Park, S Lee, H W Pritchard, H H Kim
BACKGROUND: Despite its self-pollinating characteristics, Korean ginseng germplasm is mainly maintained in clonal gene banks as there is no defined approach to the long-term conservation of its seed, including the most appropriate stage of embryo development for storage. OBJECTIVE: The aim of this study was to reveal the effect of embryo development on desiccation tolerance and cryopreservation success in ginseng seeds. MATERIALS AND METHODS: Seeds of Korean ginseng (Panax ginseng C...
July 2016: Cryo Letters
https://www.readbyqxmd.com/read/27918493/boundary-layer-detection-at-cryogenic-conditions-using-temperature-sensitive-paint-coupled-with-a-carbon-nanotube-heating-layer
#4
Kyle Z Goodman, William E Lipford, Anthony Neal Watkins
Detection of flow transition on aircraft surfaces and models can be vital to the development of future vehicles and computational methods for evaluating vehicle concepts. In testing at ambient conditions, IR thermography is ideal for this measurement. However, for higher Reynolds number testing, cryogenic facilities are often used, in which IR thermography is difficult to employ. In these facilities, temperature sensitive paint is an alternative with a temperature step introduced to enhance the natural temperature change from transition...
December 3, 2016: Sensors
https://www.readbyqxmd.com/read/27918141/structure-and-fluxionality-of-b13-probed-by-infrared-photodissociation-spectroscopy
#5
Matias R Fagiani, Xiaowei Song, Petko Petkov, Sreekanta Debnath, Sandy Gewinner, Wieland Schöllkopf, Thomas Heine, André Fielicke, Knut R Asmis
We use cryogenic ion vibrational spectroscopy to characterize the structure and fluxionality of the magic number boron cluster B13(+) . The infrared photodissociation (IRPD) spectrum of the D2 -tagged all-(11) B isotopologue of B13(+) is reported in the spectral range from 435 to 1790 cm(-1) and unambiguously assigned to a planar boron double wheel structure based on a comparison to simulated IR spectra of low energy isomers from density-functional-theory (DFT) computations. Born-Oppenheimer DFT molecular dynamics simulations show that B13(+) exhibits internal quasi-rotation already at 100 K...
December 5, 2016: Angewandte Chemie
https://www.readbyqxmd.com/read/27917583/electronic-spectroscopy-of-methylcyanodiacetylene-ch3-c5-n
#6
Michał Turowski, Urszula Szczepaniak, Thomas Custer, Marcin Gronowski, Robert Kołos
The results of a study devoted to the electronic spectroscopy of gaseous, solid, and cryogenic matrix-isolated methylcyanodiacetylene (CH3 C5 N) are reported. UV absorption and optical phosphorescence spectra of the compound are described here for the first time, and the corresponding vibronic assignments are proposed. UV absorption, studied directly or through the excitation of phosphorescence, revealed the B˜  (1) E--X˜  (1) A1 system, very weak A˜  (1) A2 -X˜  (1) A1 bands, and a strong, broad absorption feature, tentatively identified as D˜  (1) E-X˜  (1) A1 ...
December 5, 2016: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/27915153/room-temperature-structure-of-human-igg4-fc-from-crystals-analysed-in-situ
#7
Anna M Davies, Theo Rispens, Pleuni Ooijevaar-de Heer, Rob C Aalberse, Brian J Sutton
The Fc region of IgG antibodies (Cγ2 and Cγ3 domains) is responsible for effector functions such as antibody-dependent cell-mediated cytotoxicity and phagocytosis, through engagement with Fcγ receptors, although the ability to elicit these functions differs between the four human IgG subclasses. A key determinant of Fcγ receptor interactions is the FG loop in the Cγ2 domain. High resolution cryogenic IgG4-Fc crystal structures have revealed a unique conformation for this loop, which could contribute to the particular biological properties of this subclass...
December 1, 2016: Molecular Immunology
https://www.readbyqxmd.com/read/27911765/optical-magnetic-detection-of-single-neuron-action-potentials-using-quantum-defects-in-diamond
#8
John F Barry, Matthew J Turner, Jennifer M Schloss, David R Glenn, Yuyu Song, Mikhail D Lukin, Hongkun Park, Ronald L Walsworth
Magnetic fields from neuronal action potentials (APs) pass largely unperturbed through biological tissue, allowing magnetic measurements of AP dynamics to be performed extracellularly or even outside intact organisms. To date, however, magnetic techniques for sensing neuronal activity have either operated at the macroscale with coarse spatial and/or temporal resolution-e.g., magnetic resonance imaging methods and magnetoencephalography-or been restricted to biophysics studies of excised neurons probed with cryogenic or bulky detectors that do not provide single-neuron spatial resolution and are not scalable to functional networks or intact organisms...
December 6, 2016: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/27910622/low-noise-correlation-measurements-based-on-software-defined-radio-receivers-and-cooled-microwave-amplifiers
#9
Teemu Nieminen, Pasi Lähteenmäki, Zhenbing Tan, Daniel Cox, Pertti J Hakonen
We present a microwave correlation measurement system based on two low-cost USB-connected software defined radio dongles modified to operate as coherent receivers by using a common local oscillator. Existing software is used to obtain I/Q samples from both dongles simultaneously at a software tunable frequency. To achieve low noise, we introduce an easy low-noise solution for cryogenic amplification at 600-900 MHz based on single discrete HEMT with 21 dB gain and 7 K noise temperature. In addition, we discuss the quantization effects in a digital correlation measurement and determination of optimal integration time by applying Allan deviation analysis...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910570/imaging-crystal-spectrometer-for-high-resolution-x-ray-measurements-on-electron-beam-ion-traps-and-tokamaks
#10
P Beiersdorfer, E W Magee, N Hell, G V Brown
We describe a crystal spectrometer implemented on the Livermore electron beam ion traps that employ two spherically bent quartz crystals and a cryogenically cooled back-illuminated charge-coupled device detector to measure x rays with a nominal resolving power of λ/Δλ ≥ 10 000. Its focusing properties allow us to record x rays either with the plane of dispersion perpendicular or parallel to the electron beam and, thus, to preferentially select one of the two linear x-ray polarization components. Moreover, by choice of dispersion plane and focussing conditions, we use the instrument either to image the distribution of the ions within the 2 cm long trap region, or to concentrate x rays of a given energy to a point on the detector, which optimizes the signal-to-noise ratio...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910564/high-resolution-x-ray-thomson-scattering-measurements-from-cryogenic-hydrogen-jets-using-the-linac-coherent-light-source
#11
L B Fletcher, U Zastrau, E Galtier, E J Gamboa, S Goede, W Schumaker, A Ravasio, M Gauthier, M J MacDonald, Z Chen, E Granados, H J Lee, A Fry, J B Kim, C Roedel, R Mishra, A Pelka, D Kraus, B Barbrel, T Döppner, S H Glenzer
We present the first spectrally resolved measurements of x-rays scattered from cryogenic hydrogen jets in the single photon counting limit. The 120 Hz capabilities of the LCLS, together with a novel hydrogen jet design [J. B. Kim et al., Rev. Sci. Instrum. (these proceedings)], allow for the ability to record a near background free spectrum. Such high-dynamic-range x-ray scattering measurements enable a platform to study ultra-fast, laser-driven, heating dynamics of hydrogen plasmas. This measurement has been achieved using two highly annealed pyrolytic graphite crystal spectrometers to spectrally resolve 5...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910537/highly-sensitive-superconducting-circuits-at-%C3%A2-700-khz-with-tunable-quality-factors-for-image-current-detection-of-single-trapped-antiprotons
#12
H Nagahama, G Schneider, A Mooser, C Smorra, S Sellner, J Harrington, T Higuchi, M Borchert, T Tanaka, M Besirli, K Blaum, Y Matsuda, C Ospelkaus, W Quint, J Walz, Y Yamazaki, S Ulmer
We developed highly sensitive image-current detection systems based on superconducting toroidal coils and ultra-low noise amplifiers for non-destructive measurements of the axial frequencies (550-800 kHz) of single antiprotons stored in a cryogenic multi-Penning-trap system. The unloaded superconducting tuned circuits show quality factors of up to 500 000, which corresponds to a factor of 10 improvement compared to our previously used solenoidal designs. Connected to ultra-low noise amplifiers and the trap system, signal-to-noise-ratios of 30 dB at quality factors of >20 000 are achieved...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910462/a-precision-cryostat-design-for-manual-and-semi-automated-cryo-plunge-instruments
#13
Christopher J Russo, Steve Scotcher, Martin Kyte
Here we describe a bench-top cryostat system to control the temperature of liquid ethane in a cryo-plunge apparatus designed for biological specimen preparation for electron cryomicroscopy. It comprises a foam insulated Dewar containing a copper cryostat cup, whose temperature is controlled via an active feedback system to within 0.1 K. The device can easily be incorporated into existing manual and semi-automatic cryo-plunge instruments that are not equipped with cryogenic temperature control. Over the course of normal use, we find that using a cryostat is convenient, fast, and does not require special mixtures of cryogens like ethane/propane...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910455/high-resolution-measurements-of-the-dt-neutron-spectrum-using-new-cd-foils-in-the-magnetic-recoil-neutron-spectrometer-mrs-on-the-national-ignition-facility
#14
M Gatu Johnson, J A Frenje, R M Bionta, D T Casey, M J Eckart, M P Farrell, G P Grim, E P Hartouni, R Hatarik, M Hoppe, J D Kilkenny, C K Li, R D Petrasso, H G Reynolds, D B Sayre, M E Schoff, F H Séguin, K Skulina, C B Yeamans
The Magnetic Recoil neutron Spectrometer (MRS) on the National Ignition Facility measures the DT neutron spectrum from cryogenically layered inertial confinement fusion implosions. Yield, areal density, apparent ion temperature, and directional fluid flow are inferred from the MRS data. This paper describes recent advances in MRS measurements of the primary peak using new, thinner, reduced-area deuterated plastic (CD) conversion foils. The new foils allow operation of MRS at yields 2 orders of magnitude higher than previously possible, at a resolution down to ∼200 keV FWHM...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910336/high-intensity-laser-accelerated-ion-beam-produced-from-cryogenic-micro-jet-target
#15
M Gauthier, J B Kim, C B Curry, B Aurand, E J Gamboa, S Göde, C Goyon, A Hazi, S Kerr, A Pak, A Propp, B Ramakrishna, J Ruby, O Willi, G J Williams, C Rödel, S H Glenzer
We report on the successful operation of a newly developed cryogenic jet target at high intensity laser-irradiation. Using the frequency-doubled Titan short pulse laser system at Jupiter Laser Facility, Lawrence Livermore National Laboratory, we demonstrate the generation of a pure proton beam a with maximum energy of 2 MeV. Furthermore, we record a quasi-monoenergetic peak at 1.1 MeV in the proton spectrum emitted in the laser forward direction suggesting an alternative acceleration mechanism. Using a solid-density mixed hydrogen-deuterium target, we are also able to produce pure proton-deuteron ion beams...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910332/tracer-encapsulated-solid-pellet-tespel-injection-system-for-the-tj-ii-stellarator
#16
N Tamura, K J McCarthy, H Hayashi, S K Combs, C Foust, R García, N Panadero, E Pawelec, J Hernández Sánchez, M Navarro, A Soleto
A tracer-encapsulated solid pellet (TESPEL) injection system for the TJ-II stellarator was recently developed. In order to reduce the time and cost for the development, we combined a TESPEL injector provided by National Institute for Fusion Science with an existing TJ-II cryogenic pellet injection system. Consequently, the TESPEL injection into the TJ-II plasma was successfully achieved, which was confirmed by several pellet diagnostics including a normal-incidence spectrometer for monitoring a tracer impurity behavior...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910321/development-of-a-cryogenic-hydrogen-microjet-for-high-intensity-high-repetition-rate-experiments
#17
J B Kim, S Göde, S H Glenzer
The advent of high-intensity, high-repetition-rate lasers has led to the need for replenishing targets of interest for high energy density sciences. We describe the design and characterization of a cryogenic microjet source, which can deliver a continuous stream of liquid hydrogen with a diameter of a few microns. The jet has been imaged at 1 μm resolution by shadowgraphy with a short pulse laser. The pointing stability has been measured at well below a mrad, for a stable free-standing filament of solid-density hydrogen...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910317/cryogenic-setup-for-trapped-ion-quantum-computing
#18
M F Brandl, M W van Mourik, L Postler, A Nolf, K Lakhmanskiy, R R Paiva, S Möller, N Daniilidis, H Häffner, V Kaushal, T Ruster, C Warschburger, H Kaufmann, U G Poschinger, F Schmidt-Kaler, P Schindler, T Monz, R Blatt
We report on the design of a cryogenic setup for trapped ion quantum computing containing a segmented surface electrode trap. The heat shield of our cryostat is designed to attenuate alternating magnetic field noise, resulting in 120 dB reduction of 50 Hz noise along the magnetic field axis. We combine this efficient magnetic shielding with high optical access required for single ion addressing as well as for efficient state detection by placing two lenses each with numerical aperture 0.23 inside the inner heat shield...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27908108/dual-hydrogen-bonding-motifs-in-complexes-formed-between-tropolone-and-formic-acid
#19
Deacon J Nemchick, Michael K Cohen, Patrick H Vaccaro
The near-ultraviolet π(*)←π absorption system of weakly bound complexes formed between tropolone (TrOH) and formic acid (FA) under cryogenic free-jet expansion conditions has been interrogated by exploiting a variety of fluorescence-based laser-spectroscopic probes, with synergistic quantum-chemical calculations built upon diverse model chemistries being enlisted to unravel the structural and dynamical properties of the pertinent ground [X̃(1)A(')] and excited [Ã(1)A(')π(*)π] electronic states. For binary TrOH ⋅ FA adducts, the presence of dual hydrogen-bond linkages gives rise to three low-lying isomers designated (in relative energy order) as INT, EXT1, and EXT2 depending on whether docking of the FA ligand to the TrOH substrate takes place internal or external to the five-membered reaction cleft of tropolone...
November 28, 2016: Journal of Chemical Physics
https://www.readbyqxmd.com/read/27906532/medical-gas-containers-and-closures-current-good-manufacturing-practice-requirements-final-rule
#20
(no author information available yet)
The Food and Drug Administration (FDA or the Agency) is amending its current good manufacturing practice (CGMP) and labeling regulations regarding medical gases. FDA is requiring that portable cryogenic medical gas containers not manufactured with permanent gas use outlet connections have gas-specific use outlet connections that cannot be readily removed or replaced except by the manufacturer. FDA is also requiring that portable cryogenic medical gas containers and high-pressure medical gas cylinders meet certain labeling, naming, and color requirements...
November 18, 2016: Federal Register
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