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Seyed Ramin Pajoumshariati, Morteza Azizi, Daniel Wesner, Paula G Miller, Michael Shuler, Alireza Abbaspourrad
Microfluidic-based cell encapsulation has promising potential in therapeutic applications. It also provides a unique approach for studying cellular dynamics and interactions, though this concept has not yet been fully explored. No in vitro model currently exists that allows us to study the interaction between crypt cells and Peyer's patch immune cells due to the difficulty in recreating with sufficient control the two different microenvironments in the intestine in which these cell types belong. However, we demonstrate that our microfluidic technique is able to provide such precise control and that these cells can proliferate inside the microgels...
February 23, 2018: ACS Applied Materials & Interfaces
Cesar Gonzalez, Andersson Sanchez, Jeffrey Collins, Ksenia Lisova, Jason T Lee, R Michael van Dam, M Alejandro Barbieri, Cheppail Ramachandran, Stanislaw F Wnuk
The coupling of gemcitabine with functionalized carboxylic acids using peptide coupling conditions afforded 4-N-alkanoyl analogues with a terminal alkyne or azido moiety. Reaction of 4-N-tosylgemcitabine with azidoalkyl amine provided 4-N-alkyl gemcitabine with a terminal azido group. Click reaction with silane building blocks afforded 4-N-alkanoyl or 4-N-alkyl gemcitabine analogues suitable for fluorination. RP-HPLC analysis indicated better chemical stability of 4-N-alkyl gemcitabine analogues versus 4-N-alkanoyl analogues in acidic aqueous conditions...
February 12, 2018: European Journal of Medicinal Chemistry
Carla Saunders, Mohammed B Khaled, Jimmie D Weaver, Dean J Tantillo
Scaling factors are reported for use in predicting 19F NMR chemical shifts for fluorinated (hetero)aromatic compounds with relatively low levels of theory. Our recommended scaling factors were developed using a curated data set of 52 compounds, with 100 individual 19F shifts spanning a range of 153 ppm. With a maximum deviation of 6.5 ppm between experimental and computed shifts, or 4% of the range tested, these scaling factors allow for the assignment of chemical shifts to specific fluorines in multifluorinated aromatics...
February 22, 2018: Journal of Organic Chemistry
Ahmed M Embaby, Sanne Schoffelen, Christian Kofoed, Meldal Morten, Frederik Diness
Fluorobenzene probes for protein profiling through selective cysteine labeling have been developed by rational reactivity tuning. Tuning was achieved by selecting an electron-withdrawing para-substituent combined with variation of the number of fluorine substituents. Optimized probes chemo-selectively arylated cysteine residues in proteins under aqueous conditions. Probes linked to azide, biotin or a fluorophore were applicable to labeling of eGFP and albumin. Selective inhibition of cysteine proteases was also demonstrated with the probes...
February 22, 2018: Angewandte Chemie
Kumiko Yamamoto, Jiakun Li, Jeffrey A O Garber, Julian D Rolfes, Gregory B Boursalian, Jannik C Borghs, Christophe Genicot, Jérôme Jacq, Maurice van Gastel, Frank Neese, Tobias Ritter
Aryl fluorides are widely used in the pharmaceutical and agrochemical industries, and recent advances have enabled their synthesis through the conversion of various functional groups. However, there is a lack of general methods for direct aromatic carbon-hydrogen (C-H) fluorination. Conventional methods require the use of either strong fluorinating reagents, which are often unselective and difficult to handle, such as elemental fluorine, or less reactive reagents that attack only the most activated arenes, which reduces the substrate scope...
February 21, 2018: Nature
Siddesh V Hartimath, Valeria Manuelli, Rolf Zijlma, Alberto Signore, Tapan K Nayak, Anne Freimoser-Grundschober, Christian Klein, Rudi A J O Dierckx, Erik F J de Vries
Interleukin-2 (IL2) is a cytokine that can stimulate cytotoxic immune cells to attack infected and malignant cells. Unfortunately, IL2 can also cause serious immune-related toxicity. Recently, a mutant of IL2 (IL2v) with abolished CD25 binding, increased plasma half-life and less toxicity was engineered. Unlike wild-type IL2 (wt-IL2), mutant IL2v does not bind to the α-subunit (CD25) of the high affinity IL2αβγ receptor, but only to its β and γ subunit. Here, we investigated the biological properties of IL2v and compared with the wt-IL2 using fluorine-18 and PET...
January 23, 2018: Oncotarget
Sven Stadlbauer, Carmen Steinborn, Amy Klemd, Fumihiko Hattori, Ken Ohmori, Keisuke Suzuki, Roman Huber, Philipp Wolf, Carsten Gründemann
Among the known or suspected risk factors, inflammation plays an important role in infectious and non-infectious pathways leading to cancer. Green tea polyphenols have been associated with reducing inflammation and protection against carcinogenesis, especially in prostate cancer. While most of the research in this field, so far, has focussed on epigallocatechin-3- O -gallate only, we studied epicatechin-3- O -gallate, the second most abundant green tea polyphenol with essential therapeutic potential, to obtain a more detailed understanding of its anti-tumor and anti-inflammatory action...
February 21, 2018: Planta Medica
Yu Li, Qiuyan Shi, Jiajia Shao, Yaping Yuan, Zhigang Yang, Shizhen Chen, Xin Zhou, Shijun Wen, Zhong-Xing Jiang
To improve the druggability of salinomycin, a 20-epi-amino-20-deoxysalinomycin derivatives library was synthesized with high efficacy from which a few salinomycin derivatives with high potency and selectivity were identified through comprehensive cytotoxicity assay, including a fluorine-19 magnetic resonance sensitive tool molecule. Using a K-ras cellular model, salinomycin and its derivatives showed different molecular mode of action from literature reports. These results would be valuable for developing salinomycin-based cancer therapy...
February 5, 2018: European Journal of Medicinal Chemistry
Matic Resnik, Rok Zaplotnik, Miran Mozetic, Alenka Vesel
The fluorination of the polymer polyethylene terephthalate in plasma created from SF₆ or CF₄ gas at various pressures was investigated. The surface was analysed by X-ray photoelectron spectroscopy and water contact angle measurements, whereas the plasma was characterized by optical emission spectroscopy. The extent of the polymer surface fluorination was dependent on the pressure. Up to a threshold pressure, the amount of fluorine on the polymer surface and the surface hydrophobicity were similar, which was explained by the full dissociation of the SF₆ and CF₄ gases, leading to high concentrations of fluorine radicals in the plasma and thus causing the saturation of the polymer surface with fluorine functional groups...
February 21, 2018: Materials
Stefan Breuer, Martin Wilkening
Crystalline ion conductors exhibiting fast ion dynamics are of utmost importance for the development of, e.g., sensors or rechargeable batteries. In some layer-structured or nanostructured compounds fluorine ions participate in remarkably fast self-diffusion processes. As has been shown earlier, F ion dynamics in nanocrystalline, defect-rich BaF2 is much higher than that in the coarse-grained counterpart BaF2 . The thermally metastable fluoride (Ba,Ca)F2 , which can be prepared by joint high-energy ball milling of the binary fluorides, exhibits even better ion transport properties...
February 21, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Julia Schacht, Johannes Horst Budau, Nicola Gaston, Beate Paulus
The introduction of the so called fluorolytic sol-gel synthesis in 2003 gave access to previously inaccessible aluminum oxo-fluorides, thus to nanoscopic materials and, more importantly, novel catalysts. The intermediate cluster structures synthesized and stabilized by Kemnitz and coworkers have mainly been protected by iso-propoxide groups. However, since catalytic reactions take place in a large variety of media, hydrophilic analogs of those clusters would be of interest. In this manuscript, we present a computational analysis for the fluorination reaction, which represents the second part of fluorolytic sol-gel synthesis, and a theoretical study of the synthesized Al4 F4 (μ4 -O)(μ-Oi Pr)5 [H(Oi Pr)2 ] nanostructure's conversion to its hydroxylated analog Al4 F4 (μ4 -O)(μ-OH)5 [H(OH)2 ] utilizing the nudged elastic band method...
February 21, 2018: Journal of Computational Chemistry
Boyi Zhang, Jonathon E Vandezande, Ryan D Reynolds, Henry F Schaefer
Within current electronic structure theory methods, fully relativistic four-component (4c) methods based on the Dirac Hamiltonian treat spin-orbit coupling with the most rigor. The spin treatment arises naturally from the formulation and does not need to be included ad hoc. Spin-orbit splittings can provide insightful benchmark criteria for the assessment of 4c methods. However, there have not been extensive studies in this respect due to the computationally demanding nature of relativistic methods and the absence of in publicly available codes...
February 20, 2018: Journal of Chemical Theory and Computation
Wenyi Xie, Paul C Lemaire, Gregory N Parsons
The semiconductor industry faces a tremendous challenge in the development of transistor device with sub-10nm complex features. Self-limiting atomic layer etching (ALE) is essential for enabling the manufacturing of complex transistor structures. In this study, we demonstrated a thermally driven ALE process for tungsten (W) using sequential exposures of O2 and WF6. Based on the insight gained from the previous study on TiO2 thermal ALE, we proposed that etching of W could proceed in two sequential reaction steps at 300 °C: 1) oxidation of metallic tungsten using O2 or O3 to form WO3(s), and 2) formation and removal of volatile WO2F2(g) during the reaction between WO3(s) and WF6(g)...
February 20, 2018: ACS Applied Materials & Interfaces
Shu Yu, Li Wei, Xiaojing Chi, Hui Xu, Fei Ding
2-(4-Methoxyphenyl)ethyl-2-acetamido-2-deoxyb-D-pyranoside (code-named SalA-4g), an analog of salidroside, has potent neuroprotective effects. In this study, the pharmacological properties of SalA-4g were evaluated in primary cortical neurons exposed to oxygen and glucose deprivation and in a rat model of transient middle cerebral artery occlusion. The results of pharmacokinetic and brain distribution studies indicated that SalA-4g could pass through the blood-brain barrier with a relatively short elimination time...
February 15, 2018: Neuroreport
Jonathan Dickerhoff, Klaus Weisz
A (3+1)-hybrid-type G-quadruplex was substituted within its central tetrad by a single 2'-fluoro-modified guanosine. Driven by the anti-favoring nucleoside analog, a novel quadruplex fold with an inversion of a single G-tract and the conversion of a propeller into a lateral loop emerges. In addition, scalar couplings across hydrogen bonds demonstrate the formation of intra- and interresidual F***H8-C8 pseudohydrogen bonds within the modified quadruplexes. Alternative folding can be rationalized by the impact of fluorine on intermediate species based on a kinetic partitioning mechanism...
February 20, 2018: Chembiochem: a European Journal of Chemical Biology
Pingping Wang, Faqin Dong, Mingxue Liu, Huichao He, Tingting Huo, Lei Zhou, Wei Zhang
Photoelectrochemical process is an environmentally friendly technology and has a wide application in the control of environmental pollutants. Efficient nanophotocatalysts responsive to visible light are still highly attractive. In this work, α-Fe2 O3 /TiO2 were grown on fluorine doped tin oxide (FTO) substrates by hydrothermal method for photoelectrochemical reduction of Cr(VI). Compared with the separate α-Fe2 O3 and TiO2 electrodes, the composite α-Fe2 O3 /TiO2 electrodes show higher photocurrent density...
February 19, 2018: Environmental Science and Pollution Research International
Hua Fan, Ting-Ting Wang, Gang Ren, Hong-Liang Fu, Xiang-Ru Wu, Cai-Ting Chu, Wen-Hua Li
0BJECTIVE: We compared the diagnostic accuracy of contrast-enhanced computed tomography (CT), fluorine 18-labeled-fludeoxyglucose (18 F-FDG) positron emission tomography (PET)/CT and conventional magnetic resonance imaging (MRI) without and with diffusion-weighted imaging (DWI) for characterization of tubo-ovarian abscesses (TOAs) that mimic adnexal tumors. MATERIALS AND METHODS: We evaluated (retrospectively) 43 patients who underwent contrast-enhanced CT, PET/CT, conventional MRI without and with DWI, and who were found to have TOAs and complex adnexal tumors...
February 2018: Taiwanese Journal of Obstetrics & Gynecology
Jingxin Jiang, Mamoru Furuta
This study investigated the effect of fluorine (F) diffusion from a fluorinated siliconnitride passivation layer (SiNX:F-Pa) into amorphous-InGaZnO-based thin-film transistors (a-IGZO TFTs). The results of thermal desorption spectroscopy and secondary ion mass spectrometry revealed that F was introduced into the SiOX etch-stopper layer (SiOX-ES) during the deposition of a SiNX:F-Pa, and did not originate from desorption of Si-F bonds; and that long annealing times enhanced F diffusion from the SiOX-ES layer to the a-IGZO channel...
August 1, 2018: Journal of Nanoscience and Nanotechnology
Leyre Marzo, Santhosh K Pagire, Oliver Reiser, Burkhard König
Visible light photocatalysis has evolved over the last decade into a widely used method in organic synthesis. For many important transformations, such as cross-coupling reactions, alpha-amino functionalizations, cycloadditions, ATRA reactions, or fluorinations, photocatalytic variants have been reported. In this review, we try to compare classical and photocatalytic procedures for selected classes of reactions and highlight their advantages and limitations. In many cases, the photocatalytic reactions proceed at milder reaction conditions, typically at room temperature, and stoichiometric reagents are replaced by simple oxidants or reductants, like air oxygen or amines...
February 19, 2018: Angewandte Chemie
Rohan R Merchant, Jacob T Edwards, Tian Qin, Monika M Kruszyk, Cheng Bi, Guanda Che, Deng-Hui Bao, Wenhua Qiao, Lijie Sun, Michael R Collins, Olugbeminiyi O Fadeyi, Gary M Gallego, James J Mousseau, Philippe Nuhant, Phil S Baran
Cross-coupling chemistry is widely applied to carbon-carbon bond formation in the synthesis of medicines, agrochemicals, and other functional materials. Recently single-electron-induced variants of this reaction class have proven particularly useful in the formation of C(sp2 )-C(sp3 ) linkages, though certain compound classes have remained a challenge. Here we report the use of sulfones to activate the alkyl coupling partner in nickel-catalyzed radical cross-coupling with aryl zinc reagents. This method's tolerance of fluoroalkyl substituents proved particularly advantageous for the streamlined preparation of pharmaceutically-oriented fluorinated scaffolds that previously required multiple steps, toxic reagents, and non-modular retrosynthetic blueprints...
February 18, 2018: Science
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