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https://www.readbyqxmd.com/read/29156157/continuous-gradient-temperature-raman-spectroscopy-from-100-to-40%C3%A2-c-yields-new-molecular-models-of-arachidonic-acid-and-2-arachidonoyl-1-stearoyl-sn-glycero-3-phosphocholine
#1
C Leigh Broadhurst, Walter F Schmidt, Julie K Nguyen, Jianwei Qin, Kuanglin Chao, Moon S Kim
Despite its biochemical importance, a complete Raman analysis of arachidonic acid (AA, 20:4n-6) has never been reported. Gradient temperature Raman spectroscopy (GTRS) applies the temperature gradients utilized in differential scanning calorimetry (DSC) to Raman spectroscopy, providing a straightforward technique to identify molecular rearrangements that occur near and at phase transitions. Herein we utilize the GTRS technique for AA and 1-18:0, 2-20:4n-6 phosphatidyl choline (AAPC) from cryogenic to mammalian body temperatures...
December 2017: Prostaglandins, Leukotrienes, and Essential Fatty Acids
https://www.readbyqxmd.com/read/29155822/heavy-atom-effect-on-optically-excited-triplet-state-kinetics
#2
Christian Hintze, Tobias O Morgen, Malte Drescher
In several fields of research, like e.g. photosensitization, photovoltaics, organic electroluminescent devices, dynamic nuclear polarization, or pulsed dipolar electron paramagnetic resonance spectroscopy, triplet state kinetics play an important role. It is therefore desirable to tailor the kinetics of photoexcited triplet states, e.g. by exploiting the intramolecular heavy-atom effect, and to determine the respective kinetic parameters. In this work, we set out to systematically investigate the photoexcited triplet state kinetics of a series of haloanthracenes by time-resolved electron paramagnetic resonance spectroscopy in combination with synchronized laser excitation...
2017: PloS One
https://www.readbyqxmd.com/read/29154221/effects-of-aging-treatment-and-freezing-thawing-methods-on-the-quality-attributes-of-beef-from-limousin%C3%A3-holstein-friesian-and-hereford%C3%A3-holstein-friesian-crossbreeds
#3
Julia Bogdanowicz, Marek Cierach, Tomasz Żmijewski
The objective was to investigate combined effects of aging-, freezing-, thawing- treatments on the water-holding capacity, Warner-Bratzler shear force (WBSF) and sensory properties of beef. Semitendinosus muscles from two crossbreeds were analysed. Carcasses were conventionally aged (4days post mortem), muscles were separated and divided into samples. Part of the samples were frozen without wet-aging and the others were wet-aged for 3 or 6days (and then also frozen). Two freezing methods (conventional and cryogenic) and two thawing methods (at 4°C and 20°C) were applied...
October 24, 2017: Meat Science
https://www.readbyqxmd.com/read/29147825/ice-squeezing-induced-multicolor-fluorescence-emissions-from-polyacrylamide-cryogels
#4
Chun Yang, Yan Zhang, Wei-Qin Cao, Ya-Nan Yan, Jian Wang, Xiao-Feng Ji, Tao-Lin Zhong, Yu Wang
Being short of conventional chromophores, polyacrylamide is generally not regarded as a fluorescent material. Exactly the polymerization of dilute solutions of acrylamide and N,N'-methylenebisacrylamide led to thick liquids at 60 °C, showing no fluorescence. Things changed when the phase transition of water was involved. The squeezing effect of ice crystals not only created polymeric solids (cryogels) at - 20 °C, but also endowed them unexpected fluorescence emissions. The macroporous cryogels are mainly blue fluorescent polymers...
November 16, 2017: Journal of Fluorescence
https://www.readbyqxmd.com/read/29147709/four-one-dimensional-lanthanide-phenylacetate-polymers-exhibiting-luminescence-and-magnetic-cooling-spin-glass-behavior
#5
Zhong-Yi Li, Ya-Lan Xu, Xiang-Fei Zhang, Bin Zhai, Fu-Li Zhang, Jian-Jun Zhang, Chi Zhang, Su-Zhi Li, Guang-Xiu Cao
Four isostructural lanthanide coordination polymers with a phenylacetate (PAA(-)) ligand, [Ln(PAA)3(H2O)]n (Ln = Eu (1); Gd (2); Tb (3); Dy (4)), were synthesized under hydrothermal conditions. Complexes 1-4 display a one-dimensional (1D) wave chain structure bridged by the carboxylate of the PAA(-) ligand, which was generated via the in situ decarboxylation of phenylmalonic acid. Magnetic studies suggest the presence of ferromagnetic LnLn coupling in the 1D chain of 1-4. Meanwhile, 2 has a significant cryogenic magnetocaloric effect with the maximum -ΔSm of 26...
November 17, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29145727/directly-observing-micelle-fusion-and-growth-in-solution-by-liquid-cell-transmission-electron-microscopy
#6
Lucas R Parent, Evangelos Bakalis, Abelardo Ramírez-Hernández, Jacquelin K Kammeyer, Chiwoo Park, Juan de Pablo, Francesco Zerbetto, Joseph P Patterson, Nathan C Gianneschi
Amphiphilic small molecules and polymers form commonplace nanoscale macromolecular compartments and bilayers, and as such are truly essential components in all cells and in many cellular processes. The nature of these architectures, including their formation, phase changes, and stimuli-response behaviors, is necessary for the most basic functions of life, and over the past half-century, these natural micellar structures have inspired a vast diversity of industrial products, from biomedicines to detergents, lubricants, and coatings...
November 17, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29144418/nmr-based-identification-of-metabolites-in-polar-and-non-polar-extracts-of-avian-liver
#7
Fariba Fathi, Antonio Brun, Katherine H Rott, Paulo Falco Cobra, Marco Tonelli, Hamid R Eghbalnia, Enrique Caviedes-Vidal, William H Karasov, John L Markley
Metabolites present in liver provide important clues regarding the physiological state of an organism. The aim of this work was to evaluate a protocol for high-throughput NMR-based analysis of polar and non-polar metabolites from a small quantity of liver tissue. We extracted the tissue with a methanol/chloroform/water mixture and isolated the polar metabolites from the methanol/water layer and the non-polar metabolites from the chloroform layer. Following drying, we re-solubilized the fractions for analysis with a 600 MHz NMR spectrometer equipped with a 1...
November 16, 2017: Metabolites
https://www.readbyqxmd.com/read/29142330/accurate-frequency-determination-of-vibration-rotation-and-rotational-transitions-of-sih
#8
José L Doménech, Stephan Schlemmer, Oskar Asvany
The fundamental (28)SiH(+) ion has been characterized in a collaborative work, utilizing a hollow-cathode-discharge laser-spectrometer and a cryogenic ion trap spectrometer. Twenty-three vibration-rotation transitions around 4.75 μm have been detected with high accuracy. This has facilitated the first direct measurement of the pure rotational transition J = 1 ← 0 at 453056.3632(4) MHz in the trap spectrometer. The measured and accurately predicted transitions enable the search for this ion in space with IR and sub-mm telescopes...
January 31, 2017: Astrophysical Journal
https://www.readbyqxmd.com/read/29141432/probing-cluster-surface-morphology-by-cryo-spectroscopy-of-n2-on-cationic-nickel-clusters
#9
Sebastian Dillinger, Jennifer Mohrbach, Gereon Niedner-Schatteburg
We present the cryogenic (26 K) IR spectra of selected [Nin(N2)m](+) (n = 5-20, m = 1 - mmax), which strongly reveal n- and m-dependent features in the N2 stretching region, in conjunction with density functional theory modeling of some of these findings. The observed spectral features allow us to refine the kinetic classification [cf. J. Mohrbach, S. Dillinger, and G. Niedner-Schatteburg, J. Chem. Phys. 147, 184304 (2017)] and to define four classes of structure related surface adsorption behavior: Class (1) of Ni6(+), Ni13(+), and Ni19(+) are highly symmetrical clusters with all smooth surfaces of equally coordinated Ni atoms that entertain stepwise N2 adsorption up to stoichiometric N2:Nisurface saturation...
November 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29137130/halogen-metal-exchange-on-bromoheterocyclics-with-substituents-containing-an-acidic-proton-via-formation-of-a-magnesium-intermediate
#10
Qingqiang Tian, Suqin Shang, Huajun Wang, Guoqiang Shi, Zhiyao Li, Jianyong Yuan
A selective and practical bromine-metal exchange on bromoheterocyclics bearing substituents with an acidic proton under non-cryogenic conditions was developed by a simple modification of an existing protocol. Our protocol of using a combination of i-PrMgCl and n-BuLi has not only solved the problem of intermolecular quenching that often occurred when using alkyl lithium alone as the reagent for halogen-lithium exchange, but also offered a highly selective method for performing bromo-metal exchange on dibrominated arene compounds through chelation effect...
November 11, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29136815/quantitative-study-of-zinc-and-metallothioneins-in-the-human-retina-and-rpe-cells-by-mass-spectrometry-based-methodologies
#11
Sara Rodríguez-Menéndez, Beatriz Fernández, Montserrat García, Lydia Álvarez, Maria Luisa Fernández, Alfredo Sanz-Medel, Miguel Coca-Prados, Rosario Pereiro, Héctor González-Iglesias
The retina contains the highest concentration of zinc in the human eye and it is primarily associated with the retinal pigment epithelium (RPE). Metallothioneins (MTs) are the main cytosolic zinc-ion-binding proteins, exerting a tight control in the number of atoms of Zn-bound to the MTs related with their antioxidant and neuroprotective functions. In order to study the Zn-MT system in retina and RPE, we have implemented mass spectrometry (MS)-based technologies: two complementary element detection methodologies (HPLC- and laser ablation (LA)-ICP-MS) have been successfully employed to study metal content in the human eye as well as to perform speciation studies of Zn-MTs...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136366/use-of-an-efficient-measurement-uncertainty-approach-to-compare-room-temperature-and-cryogenic-sample-processing-in-the-analysis-of-chemical-contaminants-in-foods
#12
Lijun Han, Steven J Lehotay, Yelena Sapozhnikova
In this study, analytical results were compared when using different approaches to bulk food sample comminution, consisting of a vertical chopper (Blixer(®)) at room temperature and at dry ice cryogenic conditions, followed by further subsample processing (20 g) using liquid nitrogen cryogenic conditions (cryomill). Analysis of the 43 targeted spiked and incurred contaminants in a food mixture consisting of equal parts orange, apple, kale, salmon, and croaker involved QuEChERS with automated mini-column solid-phase extraction (known as ITSP) cleanup followed by low pressure gas chromatography - tandem mass spectrometry (LPGC-MS/MS)...
November 14, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/29132829/the-lipolytic-degradation-of-highly-structured-cubic-micellar-nanoparticles-of-soy-phosphatidylcholine-and-glycerol-dioleate-by-phospholipase-a2-and-triacylglycerol-lipase
#13
Maria Wadsäter, Justas Barauskas, Fredrik Tiberg, Tommy Nylander
The effects of different lipolytic enzymes on the structure of lipid liquid crystalline nano-particles (LCNP) have been investigated by cryogenic transmission electron microscopy (cryo-TEM) and synchrotron small angle X-ray diffraction (SAXD). Here we used highly structured cubic micellar (Fd3m) nanoparticles of 50/50 (wt%/wt%) soy phosphatidyl choline (SPC)/glycerol dioleate (GDO) as substrate. Two types of lipolytic enzymes were used, phospholipase A2 (PLA2) that catalysis degradation of the phospholipid component, SPC, and porcine pancreatic triacylglycerol lipase (TGL) that facilitate the hydrolysis of the diglyceride, GDO...
November 10, 2017: Chemistry and Physics of Lipids
https://www.readbyqxmd.com/read/29131635/temperature-dependent-coercive-field-measured-by-a-quantum-dot-strain-gauge
#14
Yan Chen, Yang Zhang, Robert Keil, Michael Zopf, Fei Ding, Oliver G Schmidt
Coercive fields of piezoelectric materials can be strongly influenced by environmental temperature. We investigate this influence using a heterostructure consisting of a single crystal piezoelectric film and a quantum dots containing membrane. Applying electric field leads to a physical deformation of the piezoelectric film, thereby inducing strain in the quantum dots and thus modifying their optical properties. The wavelength of the quantum dot emission shows butterfly-like loops, from which the coercive fields are directly derived...
November 15, 2017: Nano Letters
https://www.readbyqxmd.com/read/29128698/seminal-plasma-antioxidants-are-directly-involved-in-boar-sperm-cryotolerance
#15
Junwei Li, Isabel Barranco, Asta Tvarijonaviciute, Manuel F Molina, Emilio A Martinez, Heriberto Rodriguez-Martinez, Inmaculada Parrilla, Jordi Roca
Boar ejaculates are ejected in fractions with a specific composition in terms of sperm numbers and seminal plasma (SP), which is reflected in the varying sperm cryotolerance observed among different fractions. As boar sperm are particularly sensitive to oxidative stress, this study evaluated the role of SP antioxidants in the observed differences in sperm cryotolerance among ejaculate fractions. Ten ejaculates from five boars were manually collected in fractions: the first 10 mL of the sperm-rich fraction (SRF), the rest of the SRF and the post-SRF...
October 31, 2017: Theriogenology
https://www.readbyqxmd.com/read/29127357/critical-switching-current-density-induced-by-spin-hall-effect-in-magnetic-structures-with-first-and-second-order-perpendicular-magnetic-anisotropy
#16
Seok Jin Yun, Kyung-Jin Lee, Sang Ho Lim
In this study, we derive analytical expressions for the critical switching current density induced by spin Hall effect in magnetic structures with the first- and second-order perpendicular magnetic anisotropy. We confirm the validity of the expressions by comparing the analytical results with those obtained from a macrospin simulation. Moreover, we find that for a particular thermal stability parameter, the switching current density can be minimized for a slightly positive second-order perpendicular magnetic anisotropy and the minimum switching current density can further be tuned using an external magnetic field...
November 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29125651/an-ideal-molecular-sieve-for-acetylene-removal-from-ethylene-with-record-selectivity-and-productivity
#17
Bin Li, Xili Cui, Daniel O'Nolan, Hui-Min Wen, Mengdie Jiang, Rajamani Krishna, Hui Wu, Rui-Biao Lin, Yu-Sheng Chen, Daqiang Yuan, Huabin Xing, Wei Zhou, Qilong Ren, Guodong Qian, Michael J Zaworotko, Banglin Chen
Realization of ideal molecular sieves, in which the larger gas molecules are completely blocked without sacrificing high adsorption capacities of the preferred smaller gas molecules, can significantly reduce energy costs for gas separation and purification and thus facilitate a possible technological transformation from the traditional energy-intensive cryogenic distillation to the energy-efficient, adsorbent-based separation and purification in the future. Although extensive research endeavors are pursued to target ideal molecular sieves among diverse porous materials, over the past several decades, ideal molecular sieves for the separation and purification of light hydrocarbons are rarely realized...
November 10, 2017: Advanced Materials
https://www.readbyqxmd.com/read/29125299/charge-driven-fluorescence-blinking-in-carbon-nanodots
#18
Syamantak Khan, Weixing Li, Narain Karedla, Jan Thiart, Ingo Gregor, Anna M Chizhik, Joerg Enderlein, Chayan Kanti Nandi, Alexey I Chizhik
This study focuses on the mechanism of fluorescence blinking of single carbon nanodots, which is one of their key but less understood properties. The results of our single particle fluorescence study show that the mechanism of carbon nanodots blinking has remarkable similarities with that of semiconductor quantum dots. In particular, the temporal behavior of carbon nanodot blinking follows a power law both at room and at cryogenic temperatures. Our experimental data suggests that static quenching via Dexter type electron transfer between surface groups of a nanoparticle plays a major role in the transition of carbon nanodots to off- or grey states, whereas the transition back to on-states is governed by an electron tunneling from the particle's core...
November 10, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/29124539/stably-fluorescent-cell-line-of-human-ovarian-epithelial-cancer-cells-sk-ov-3ip-red
#19
E V Konovalova, A A Shulga, S P Chumakov, Yu M Khodarovich, Eui-Jeon Woo, S M Deev
Stable red fluorescing line of human ovarian epithelial cancer cells SK-OV-3ip-red was generated expressing gene coding for protein TurboFP635 (Katushka) fluorescing in the far-red spectrum region with excitation and emission peaks at 588 and 635 nm, respectively. Fluorescence of SK-OV-3ip-red line remained high during long-term cell culturing and after cryogenic freezing. The obtained cell line SK-OV-3ip-red can serve a basis for a model of a scattered tumor with numerous/extended metastases and used both for testing anticancer drugs inhibiting metastasis growth and for non-invasive monitoring of the growth dynamics with high precision...
November 10, 2017: Bulletin of Experimental Biology and Medicine
https://www.readbyqxmd.com/read/29124100/data-on-conceptual-design-of-cryogenic-energy-storage-system-combined-with-liquefied-natural-gas-regasification-process
#20
Inkyu Lee, Jinwoo Park, Il Moon
This paper describes data of an integrated process, cryogenic energy storage system combined with liquefied natural gas (LNG) regasification process. The data in this paper is associated with the article entitled "Conceptual Design and Exergy Analysis of Combined Cryogenic Energy Storage and LNG Regasification Processes: Cold and Power Integration" (Lee et al., 2017) [1]. The data includes the sensitivity case study dataset of the air flow rate and the heat exchanging feasibility data by composite curves. The data is expected to be helpful to the cryogenic energy process development...
December 2017: Data in Brief
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