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Ionic contrast

Benjamin C Hudson, Alessia Battigelli, Michael D Connolly, John Edison, Ryan K Spencer, Stephen Whitelam, Ronald N Zuckermann, Anant K Paravastu
Peptoid nanosheets are supramolecular protein-mimetic materials that form from amphiphilic polypeptoids with aromatic and ionic sidechains. Nanosheets have been studied at the nanometer scale, but molecular structure has been difficult to probe. We report the use of 13 C-13 C dipolar recoupling solid-state NMR measurements to reveal the configuration of backbone amide bonds selected by 13 C isotopic labeling of adjacent α-carbons. Measurements on the same molecules in the amorphous state and in nanosheets revealed that amide bonds in the center of the amino block of peptoid (NaeNpe)7 -(NceNpe)7 (B28) favor the trans configuration in the amorphous state and the cis configuration in the nanosheet...
April 16, 2018: Journal of Physical Chemistry Letters
Takashi Hongo, Satoshi Nozaki, Midori Tsuchiya, Mototaka Inaba, Kenji Takahashi, Toshifumi Fujiwara
Case: Contrast medium-induced transient leukopenia is very rare. Here, we report a case of a 73-year-old man diagnosed with contrast media-induced transient leukopenia. The patient underwent abdominal contrast-enhanced computed tomography, where he was given non-ionic iodinated contrast medium i.v. His medical history included an allergic reaction to a different contrast medium. One hour later, the patient was admitted to the emergency department complaining of chest discomfort. He had leukopenia and a fever (temperature of 38...
April 2018: Acute Medicine & Surgery
Fei Yang, Michael Anderson, Shaoqiu He, Kimberly Stephens, Yu Zheng, Zhiyong Chen, Srinivasa N Raja, Felix Aplin, Yun Guan, Gene Fridman
The assertion that large-diameter nerve fibers have low thresholds and small-diameter fibers have high thresholds in response to electrical stimulation has been held in a nearly axiomatic regard in the field of neuromodulation and neuroprosthetics. In contrast to the short pulses used to evoke action potentials, long-duration ionic direct current has been shown to block neural activity. We propose that the main determinant of the neural sensitivity to direct current block is not the size of the axon but the types of voltage-gated sodium channels prevalent in its neural membrane...
April 2018: Science Advances
Vincent P Swamy, Hirekodathakallu V Thulasiram, Federico Rastrelli, Giacomo Saielli
We present the 1H, 13C and 15N NMR chemical shifts of bulk ionic liquids based on 1-butyl-3-methylimidazolium (the cation also known as 1-butyl-3-picolinium) halides (Cl-, Br- and I-) and tribromide (Br3-) salts. A characterization in solution of the analogous ICl2- and I3- salts is also reported. A series of DFT calculations has been run to predict the features of the NMR spectra of the pure ILs based on a few selected supramolecular ionic aggregates. To test the effect of temperature, and vibrational and conformational motions, only for the chloride salt, we also run first-principles molecular dynamics simulations of the ion pair in the gas phase, using the ADMP scheme (Atom Centered Density Matrix Propagation molecular dynamics model)...
April 12, 2018: Physical Chemistry Chemical Physics: PCCP
Jacob B Campbell, Mads Kuhlmann Andersen, Johannes Overgaard, Jon F Harrison
Oxygen limitation plays a key role in many pathologies; yet, we still lack a fundamental understanding of the mechanisms responsible for variation in anoxia tolerance. Most vertebrate studies suggest that anoxia tolerance involves the ability to maintain cellular ATP despite the loss of aerobic metabolism. However, insects such as adult D. melanogaster are able to survive long periods of anoxia (LT50: ∼8 h) in a hypo-energetic state characterized by low [ATP]. In this study, we tested for possible mechanisms that allow D...
April 3, 2018: Journal of Experimental Biology
Ewa Anna Oprzeska-Zingrebe, Jens Smiatek
Ionic liquids (ILs) are versatile solvents for a broad range of biotechnological applications. Recent experimental and simulation results highlight the potential benefits of dilute ILs in aqueous solution (aqueous ILs) in order to modify protein and DNA structures systematically. In contrast to a limited number of standard co-solutes like urea, ectoine, trimethylamine-N-oxide (TMAO), or guanidinium chloride, the large amount of possible cation and anion combinations in aqueous ILs can be used to develop tailor-made stabilizers or destabilizers for specific purposes...
April 2, 2018: Biophysical Reviews
Adil Baskiran, Aysegul Sagir Kahraman, Ipek Balikci Cicek, Tolga Sahin, Burak Isik, Sezai Yilmaz
OBJECTIVE: The aim of the present study was to retrospectively evaluate the difference between the preoperative estimated volume and the actual intraoperative graft volume determined in donor right hepatectomies and to evaluate the possible effect of age, gender, and body mass index on the difference. METHODS: A total of 225 donor hepatectomies performed at the center between 2016 and 2017 were evaluated for the study. Left hepatectomies and left lateral segmentectomies were excluded from the analysis...
2018: Northern Clinics of Istanbul
Fatma Beyazal Celiker, Levent Tumkaya, Adnan Yilmaz, Zerrin Ozergin Coskun, Metin Celiker, Fatih Oghan, Tolga Mercantepe, Suat Terzi, Engin Dursun
AIM: The aim of this prospective animal study is to investigate the influence of multiple administrations of macrocyclic ionic (gadoteric acid) and linear nonionic (gadodiamide) gadolinium-based contrast agents (GBCA) on submandibular gland tissue (SGT) of the rats. MATERIAL AND METHOD: Twenty-four Sprague Dawley female rats were included the study. Group 1 was determined as a control group (n = 6). Group 2 was determined as saline group (n = 6). Group 3 was determined as Omniscan group (n = 6) and received only intraperitoneal (IP) 0...
March 31, 2018: European Archives of Oto-rhino-laryngology
Yohei Nakanishi, Ryohei Ishige, Hiroki Ogawa, Keita Sakakibara, Kohji Ohno, Takashi Morinaga, Takaya Sato, Toshiji Kanaya, Yoshinobu Tsujii
Using ultra-small angle X-ray scattering (USAXS), we analyzed the higher-order structures of nanoparticles with a concentrated brush of an ionic liquid (IL)-type polymer (concentrated-polymer-brush-modified silica particle; PSiP) in an IL and the structure of the swollen shell layer of PSiP. Homogeneous mixtures of PSiP and IL were successfully prepared by the solvent-casting method involving the slow evaporation of a volatile solvent, which enabled a systematic study over an exceptionally wide range of compositions...
March 28, 2018: Journal of Chemical Physics
Sonja Schmid, Thorsten Hugel
Single molecule time traces reveal the time evolution of unsynchronized kinetic systems. Especially single molecule Förster resonance energy transfer (smFRET) provides access to enzymatically important time scales, combined with molecular distance resolution and minimal interference with the sample. Yet the kinetic analysis of smFRET time traces is complicated by experimental shortcomings-such as photo-bleaching and noise. Here we recapitulate the fundamental limits of single molecule fluorescence that render the classic, dwell-time based kinetic analysis unsuitable...
March 28, 2018: Journal of Chemical Physics
Daniele Preziosi, Laura Lopez-Mir, Xiaoyan Li, Tom Cornelissen, Jin Hong Lee, Felix Trier, Karim Bouzehouane, Sergio Valencia, Alexandre Gloter, Agnès Barthélémy, Manuel Bibes
Perovskite rare-earth nickelates RNiO3 are prototype correlated oxides displaying a metal-insulator transition (MIT) at a temperature tunable by the ionic radius of the rare-earth R. Although its precise origin remains a debated topic, the MIT can be exploited in various types of applications, notably for resistive switching and neuromorphic computation. So far, the MIT has been mostly studied by macroscopic techniques, and insights into its nanoscale mechanisms were only provided recently by X-ray photoemission electron microscopy through absorption line shifts, used as an indirect proxy to the resistive state...
March 28, 2018: Nano Letters
Jing Zhao, Victorine Josiane Frauenkron-Machedjou, Alexander Fulton, Leilei Zhu, Mehdi D Davari, Karl-Erich Jaeger, Ulrich Schwaneberg, Marco Bocola
Understanding of the structural and dynamic properties of enzymes in non-aqueous media (e.g., ionic liquids, ILs) is highly attractive for protein engineers and synthetic biochemists. Despite a growing number of molecular dynamics (MD) simulation studies on the influence of different ILs on wild-type enzymes, the effects of various amino acid substitutions on the stability and activity of enzymes in ILs remain to be unraveled at the molecular level. Herein, we selected fifty previously reported Bacillus subtilis lipase A (BSLA) variants with increased resistance towards an IL (15 vol% 1-butyl-3-methylimidazolium trifluoromethanesulfonate; [Bmim][TfO]), and also ten non-resistant BSLA variants for a MD simulation study to identify the underlying molecular principles...
March 26, 2018: Physical Chemistry Chemical Physics: PCCP
Lu Wang, Xiaojiang Xie, Tianchi Cao, Jérôme Bosset, Eric Bakker
Ion-selective optical microsensors based on surface modified polystyrene (PS) beads with positively charged lipophilic solvatochromic dye (SD) on the surface, with K+ as model ion, are studied here for the first time. Water soluble SDs are expelled to the aqueous phase by ion-exchange with the cationic analyte of interest, resulting in a detectable color change. In contrast, lipophilic SDs are more attractive as they appear to remain anchored onto the surface after expulsion from the sensing phase. This transfers just the ionic chromophore functionality into the aqueous phase and allows the system to act as a reversible, truly self-contained sensor...
March 25, 2018: Chemistry: a European Journal
Huayna Terraschke, Jacob Olchowka, Eugenie Geringer, Aline Varella Rodrigues, Claudia Wickleder
This work describes a novel ionic liquid (IL)-assisted synthesis strategy for a direct and easy production of Eu2+ -doped nanoparticles (NPs), where ILs are also used as fluoride sources to avoid the use of elemental fluorine or toxic hydrofluoric acid. Up to now, the direct synthesis of Eu2+ -doped nanophosphors consisted of an enormous challenge, due to the oxidation to Eu3+ observed in hydrous solution, which is commonly used for the preparation of NPs, generating lattice defects and undesired particle growth or agglomeration by additional reducing steps at high temperatures...
March 24, 2018: Small
Stefan C J Meskers
The reflection of infrared light by ionic crystals with cubic symmetry such as lithium fluoride, LiF, is analyzed in terms of phonon-polaritons. In contrast to the conventional view on phonon-polaritons that uses the Coulomb gauge and assumes a purely local dielectric response of the material, we here develop an alternative description making use of the Lorentz gauge. This involves retarded interactions between charges, implying a non-local response of the material to electromagnetic radiation. The resulting new phonon-polariton dispersion relation features polaritons with negative group velocity in the frequency range in between the transverse (ωT ) and longitudinal frequency (ωL )...
March 21, 2018: Journal of Chemical Physics
Ponarulselvam Sekar, Duen-Yi Huang, Shwu-Fen Chang, Wan-Wan Lin
Extracellular adenosine 5'-triphosphate (ATP) is a damage-associated molecular pattern and contributes to inflammation associated diseases including cancer. Extracellular acidosis is a novel danger signal in the inflammatory sites, where it can modulate inflammation, immunity and tumor growth. Extracellular acidification was shown to inhibit P2X7-mediated channel currents, while it remains unknown how acidification and P2X7 together affect cellular responses. Here, we treated BV-2 microglial cells with ATP in a short period (<15 min) or a sustained acidified condition...
February 27, 2018: Oncotarget
Elide Formentin, Cristina Sudiro, Giorgio Perin, Samantha Riccadonna, Elisabetta Barizza, Elena Baldoni, Enrico Lavezzo, Piergiorgio Stevanato, Gian Attilio Sacchi, Paolo Fontana, Stefano Toppo, Tomas Morosinotto, Michela Zottini, Fiorella Lo Schiavo
Salinity tolerance has been extensively investigated in recent years due to its agricultural importance. Several features, such as the regulation of ionic transporters and metabolic adjustments, have been identified as salt tolerance hallmarks. Nevertheless, due to the complexity of the trait, the results achieved to date have met with limited success in improving the salt tolerance of rice plants when tested in the field, thus suggesting that a better understanding of the tolerance mechanisms is still required...
2018: Frontiers in Plant Science
Linda K Bruetzel, Philipp Walker, Thomas Gerling, Hendrik Dietz, Jan Lipfert
Self-assembled DNA structures enable creation of specific shapes at the nm-µm scale with molecular resolution. The creation of functional DNA assemblies will likely require dynamic structures that can undergo controllable conformational changes. DNA devices based on shape complementary stacking interactions have been demonstrated to undergo reversible conformational changes triggered by changes in ionic environment or temperature. An experimentally unexplored aspect is how quickly conformational transitions of large synthetic DNA origami structures can actually occur...
March 20, 2018: Nano Letters
Chao Han, Paul N Williams, Jinghua Ren, Zhaode Wang, Xu Fang, Di Xu, Xianchuan Xie, Jinju Geng, Lena Q Ma, Jun Luo
Phosphite (P+III ) is of emerging chemical interest due to its importance within the global phosphorus cycle. Yet, to date, precise/accurate measurements of P+III are still lacking due to the inherent analytical challenges linked to its instability/ease of oxidation and ultra-trace concentration. Here, we present the first in-situ sampling and speciation analysis method, for dissolved P+III , using the diffusive-gradients-in-thin-films (DGT) technique, combined with capillary-column-configured-dual-ion-chromatography (CC-DIC)...
March 13, 2018: Water Research
Federico Davini, Sara Ricciardi, Carmelina Cristina Zirafa, Ilenia Cavaliere, Gaetano Romano, Franca Melfi
Background: The incidental detection of solitary pulmonary nodule (SPN) is currently increasing due to the widespread use of computed tomography (CT) during the follow up in oncological patients or in screening trials. A quick and definitive histological diagnosis of these nodes is mandatory as, in case of primitive lung cancer, an early detection could improve both surgical results and prognosis. The minimally invasive pulmonary resection (MIPR) is the gold standard procedure for diagnosis and treatment of small lung nodules, but it can be difficult to localize deep nonpalpable nodes that lie in the lung parenchyma...
2018: Journal of Visualized Surgery
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