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ACS Omega

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https://www.readbyqxmd.com/read/29978149/synthesis-affinity-for-complementary-rna-and-dna-and-enzymatic-stability-of-triazole-linked-locked-nucleic-acids-t-lnas
#1
Pawan Kumar, Lynda Truong, Ysobel Ruth Baker, Afaf Helmy El-Sagheer, Tom Brown
Dinucleoside phosphoramidites containing a triazole internucleotide linkage flanked by locked nucleic acid (LNA) were synthesized and incorporated into oligonucleotides (ONs). ONs bearing both LNA and triazole at multiple sites were obtained and their biophysical properties including enzymatic stability and binding affinity for RNA and DNA targets were studied. t-LNAs with four incorporations of a dinucleoside monomer having LNA on either side of the triazole linkage bind to their RNA target with significantly higher affinity and greater specificity than unmodified oligonucleotides, and are remarkably stable to nuclease degradation...
June 30, 2018: ACS Omega
https://www.readbyqxmd.com/read/29978148/nonprotecting-group-synthesis-of-a-phospholipase-c-activatable-probe-with-an-azo-free-quencher
#2
Benjamin K Liebov, Alejandro D Arroyo, Natalia I Rubtsova, Sofya A Osharovich, E James Delikatny, Anatoliy V Popov
The near-infrared fluorescent activatable smart probe Pyro-phosphatidylethanolamine (PtdEtn)-QSY was synthesized and observed to selectively fluoresce in the presence of phosphatidylcholine-specific phospholipase C (PC-PLC). PC-PLC is an important biological target as it is known to be upregulated in a variety of cancers, including triple negative breast cancer. Pyro-PtdEtn-QSY features a QSY21 quenching moiety instead of the Black Hole Quencher-3 (BHQ-3) used previously because the latter contains an azo bond, which could lead to biological instability...
June 30, 2018: ACS Omega
https://www.readbyqxmd.com/read/29978147/analysis-of-carbonyl-compounds-in-ambient-air-by-a-microreactor-approach
#3
Mingxiao Li, Qi Li, Michael H Nantz, Xiao-An Fu
Aldehydes including formaldehyde, acetaldehyde, and acrolein are toxic organic components of air pollution that cause lung cancer and cardiovascular disease with chronic exposure. The commonly used method for determining the levels of carbonyl compounds based on the derivatizing agent 2,4-dinitrophenylhydrazine is of limited use for ketones and unsaturated aldehydes because of issues such as low capture efficiencies, unstable derivatives, and long sample collection times. This work details the analysis of carbonyls in ambient air by a microreactor approach...
June 30, 2018: ACS Omega
https://www.readbyqxmd.com/read/29978146/synthesis-of-unsaturated-precursors-for-parahydrogen-induced-polarization-and-molecular-imaging-of-1-13-c-acetates-and-1-13-c-pyruvates-via-side-arm-hydrogenation
#4
Nikita V Chukanov, Oleg G Salnikov, Roman V Shchepin, Kirill V Kovtunov, Igor V Koptyug, Eduard Y Chekmenev
Hyperpolarized forms of 1-13 C-acetates and 1-13 C-pyruvates are used as diagnostic contrast agents for molecular imaging of many diseases and disorders. Here, we report the synthetic preparation of 1-13 C isotopically enriched and pure from solvent acetates and pyruvates derivatized with unsaturated ester moiety. The reported unsaturated precursors can be employed for NMR hyperpolarization of 1-13 C-acetates and 1-13 C-pyruvates via parahydrogen-induced polarization (PHIP). In this PHIP variant, Side arm hydrogenation (SAH) of unsaturated ester moiety is followed by the polarization transfer from nascent parahydrogen protons to 13 C nucleus via magnetic field cycling procedure to achieve hyperpolarization of 13 C nuclear spins...
June 30, 2018: ACS Omega
https://www.readbyqxmd.com/read/29978145/exposure-to-bisphenol-a-bisphenol-f-and-bisphenol-s-in-u-s-adults-and-children-the-national-health-and-nutrition-examination-survey-2013-2014
#5
Hans-Joachim Lehmler, Buyun Liu, Manuel Gadogbe, Wei Bao
Bisphenol F (BPF) and bisphenol S (BPS) are replacing bisphenol A (BPA) in the manufacturing of products containing polycarbonates and epoxy resins. Data on current human exposure levels of these substitutes are needed to aid in the assessment of their human health risks. This study analyzed urinary bisphenol levels in adults ( N = 1808) and children ( N = 868) participating in the National Health and Nutrition Examination Survey (NHANES) 2013-2014 and investigated demographic and lifestyle factors associated with urinary levels of bisphenols...
June 30, 2018: ACS Omega
https://www.readbyqxmd.com/read/29978144/dandelion-like-microspherical-mcm-22-zeolite-using-bp-2000-as-a-hard-template
#6
Anderson Schwanke, Jhonny Villarroel-Rocha, Karim Sapag, Urbano Díaz, Avelino Corma, Sibele Pergher
The chemistry between layered MWW zeolite and carbon black pearls (BP 2000) as an inexpensive hard template was investigated to develop a rational one-pot synthesis of MCM-22 microspheres. The characterization results showed that the insertion of BP 2000 in the gel synthesis did not substantially compromise the crystallinity and microporosity, and the microscopic analyses showed that BP 2000 played a key role in controlling the final morphology of the MCM-22 zeolite, creating beautiful dandelion-like microspherical particles...
June 30, 2018: ACS Omega
https://www.readbyqxmd.com/read/29978143/insights-into-membrane-translocation-of-protegrin-antimicrobial-peptides-by-multistep-molecular-dynamics-simulations
#7
Pin-Kuang Lai, Yiannis N Kaznessis
Protegrin-1 (PG-1) is a cationic arginine-rich antimicrobial peptide. It is widely accepted that PG-1 induces membrane disruption by forming pores that lead to cell death. However, the insertion mechanism for these highly cationic peptides into the hydrophobic membrane environment is still poorly understood at the molecular scale. It has previously been determined that the association of arginine guanidinium and lipid phosphate groups results in strong bidentate bonds that stabilize peptide-lipid complexes...
June 30, 2018: ACS Omega
https://www.readbyqxmd.com/read/29876540/spatial-and-temporal-confined-photothermolysis-of-cancer-cells-mediated-by-hollow-gold-nanospheres-targeted-to-epidermal-growth-factor-receptors
#8
Geng Ku, Qian Huang, Xiaoxia Wen, John Ye, David Piwnica-Worms, Chun Li
To date, a few studies have investigated the potential use of a short-pulsed laser in selective tumor cell destruction or its mechanism of cell killing. Computer simulation of the spatial and temporal profiles of temperature elevation after pulsed laser irradiation on an infinitesimal point source estimated that the temperature reached its highest point at ∼35 ns after a single 15 ns laser pulse. Moreover, temperature elevation was confined to a radius of sub-micrometer and returned to baseline within 100 ns...
May 31, 2018: ACS Omega
https://www.readbyqxmd.com/read/29876539/modulation-of-cellular-response-to-arsenic-trioxide-toxicity-by-resveratrol
#9
Bodhisattwa Mondal, Hongxia Chen, Weihua Wen, Ercole L Cavalieri, Eleanor G Rogan, Muhammad Zahid
Arsenic trioxide (As2 O3 ) is an environmental carcinogen and a putative endocrine disruptor. Resveratrol has been shown to reverse As2 O3 -induced oxidative damage. In immortalized but nontransformed estrogen receptor α-negative human breast cells (MCF10A), we observed that 25 μM resveratrol ameliorated As2 O3 -induced cytotoxicity. As2 O3 , in the presence or absence of 25 μM resveratrol, induced quinone reductase (NAD(P)H quinone dehydrogenase 1), via the induction of NFE2-related factor 2. As2 O3 caused a repression of cytochrome P450 (CYP)1B1, but the addition of 25 μM resveratrol rescued the expression of cytochrome P450 1B1 and kept it at a constant level...
May 31, 2018: ACS Omega
https://www.readbyqxmd.com/read/29876538/stability-of-a-series-of-bodipys-in-acidic-conditions-an-experimental-and-computational-study-into-the-role-of-the-substituents-at-boron
#10
Maodie Wang, M Graça H Vicente, Deanna Mason, Petia Bobadova-Parvanova
Boron-dipyrromethene (BODIPY) dyes have been extensively investigated in recent years for a variety of bioanalytical and bioimaging applications. The success of these applications relies on the stability of BODIPYs, particularly under acidic conditions. In this work, the stability of a series of 4,4'-disubstituted BODIPYs (-F, -CN, -Ph, -Me, -OMe) toward addition of excess trifluoroacetic acid (TFA) was studied systematically and comprehensively through 11 B and 1 H NMR, UV-vis, fluorescence, thin layer chromatography, mass spectrometry, and infrared...
May 31, 2018: ACS Omega
https://www.readbyqxmd.com/read/29876537/reaction-of-n-n-dimethyltryptamine-with-dichloromethane-under-common-experimental-conditions
#11
Lee E Dunlap, David E Olson
A large number of clinically used drugs and experimental pharmaceuticals possess the N , N -dimethyltryptamine (DMT) structural core. Previous reports have described the reaction of this motif with dichloromethane (DCM), a common laboratory solvent used during extraction and purification, leading to the formation of an undesired quaternary ammonium salt byproduct. However, the kinetics of this reaction under various conditions have not been thoroughly described. Here, we report a series of experiments designed to simulate the exposure of DMT to DCM that would take place during extraction from plant material, biphasic aqueous work-up, or column chromatography purification...
May 31, 2018: ACS Omega
https://www.readbyqxmd.com/read/29732454/chemically-treated-3d-printed-polymer-scaffolds-for-biomineral-formation
#12
Richard J Jackson, P Stephen Patrick, Kristopher Page, Michael J Powell, Mark F Lythgoe, Mark A Miodownik, Ivan P Parkin, Claire J Carmalt, Tammy L Kalber, Joseph C Bear
We present the synthesis of nylon-12 scaffolds by 3D printing and demonstrate their versatility as matrices for cell growth, differentiation, and biomineral formation. We demonstrate that the porous nature of the printed parts makes them ideal for the direct incorporation of preformed nanomaterials or material precursors, leading to nanocomposites with very different properties and environments for cell growth. Additives such as those derived from sources such as tetraethyl orthosilicate applied at a low temperature promote successful cell growth, due partly to the high surface area of the porous matrix...
April 30, 2018: ACS Omega
https://www.readbyqxmd.com/read/29732453/pyrimidine-nucleosides-with-a-reactive-%C3%AE-chlorovinyl-sulfone-or-%C3%AE-keto-sulfone-group-at-the-c5-position-their-reactions-with-nucleophiles-and-electrophiles-and-their-polymerase-catalyzed-incorporation-into-dna
#13
Sazzad H Suzol, A Hasan Howlader, Zhiwei Wen, Yaou Ren, Eduardo E Laverde, Carol Garcia, Yuan Liu, Stanislaw F Wnuk
Transition-metal-catalyzed chlorosulfonylation of 5-ethynylpyrimidine nucleosides provided ( E )-5-(β-chlorovinyl)sulfones A , which undergo nucleophilic substitution with amines or thiols affording B . The treatment of vinyl sulfones A with ammonia followed by acid-catalyzed hydrolysis of the intermediary β-sulfonylvinylamines gave 5-(β-keto)sulfones C . The latter reacts with electrophiles, yielding α-carbon-alkylated or -sulfanylated analogues D . The 5'-triphosphates of A and C were incorporated into double-stranded DNA, using open and one-nucleotide gap substrates, by human or Escherichia coli DNA-polymerase-catalyzed reactions...
April 30, 2018: ACS Omega
https://www.readbyqxmd.com/read/29732452/katg-mediated-oxidation-leading-to-reduced-susceptibility-of-bacteria-to-kanamycin
#14
Peter C Loewen, P Malaka De Silva, Lynda J Donald, Jacek Switala, Jacylyn Villanueva, Ignacio Fita, Ayush Kumar
Resistance to antibiotics has become a serious problem for society, and there are increasing efforts to understand the reasons for and sources of resistance. Bacterial-encoded enzymes and transport systems, both innate and acquired, are the most frequent culprits for the development of resistance, although in Mycobacterium tuberculosis , the catalase-peroxidase, KatG, has been linked to the activation of the antitubercular drug isoniazid. While investigating a possible link between aminoglycoside antibiotics and the induction of oxidative bursts, we observed that KatG reduces susceptibility to aminoglycosides...
April 30, 2018: ACS Omega
https://www.readbyqxmd.com/read/29732451/gold-i-complexes-of-the-geminal-phosphinoborane-t-bu-2-pch-2-bph-2
#15
Devin H A Boom, Andreas W Ehlers, Martin Nieger, Marc Devillard, Ghenwa Bouhadir, Didier Bourissou, J Chris Slootweg
In this work, we explored the coordination properties of the geminal phosphinoborane t Bu2 PCH2 BPh2 ( 2 ) toward different gold(I) precursors. The reaction of 2 with an equimolar amount of the sulfur-based complex (Me2 S)AuCl resulted in displacement of the SMe2 ligand and formation of linear phosphine gold(I) chloride 3 . Using an excess of ligand 2 , bisligated complex 4 was formed and showed dynamic behavior at room temperature. Changing the gold(I) metal precursor to the phosphorus-based complex, (Ph3 P)AuCl impacted the coordination behavior of ligand 2 ...
April 30, 2018: ACS Omega
https://www.readbyqxmd.com/read/29732450/mutations-alter-rna-mediated-conversion-of-human-prions
#16
Erik J Alred, Izra Lodangco, Jennifer Gallaher, Ulrich H E Hansmann
Prion diseases are connected with self-replication and self-propagation of misfolded proteins. The rate-limiting factor is the formation of the initial seed. We have recently studied the early stages in the conversion between functional PrPC and the infectious scrapie PrPSC form, triggered by the binding of RNA. Here, we study how this process is modulated by the prion sequence. We focus on residues 129 and 178, which are connected to the hereditary neurodegenerative disease fatal familial insomnia.
April 30, 2018: ACS Omega
https://www.readbyqxmd.com/read/29732449/integration-of-magnetic-bead-based-cell-selection-into-complex-isolations
#17
Hannah M Pezzi, David J Niles, Jennifer L Schehr, David J Beebe, Joshua M Lang
Magnetic bead-based analyte capture has emerged as a ubiquitous method in cell isolation, enabling the highly specific capture of target populations through simple magnetic manipulation. To date, no "one-size fits all" magnetic bead has been widely adopted leading to an overwhelming number of commercial beads. Ultimately, the ideal bead is one that not only facilitates cell isolation but also proves compatible with the widest range of downstream applications and analytic endpoints. Despite the diverse offering of sizes, coatings, and conjugation chemistries, few studies exist to benchmark the performance characteristics of different commercially available beads; importantly, these bead characteristics ultimately determine the ability of a bead to integrate into the user's assay...
April 30, 2018: ACS Omega
https://www.readbyqxmd.com/read/29732448/a-new-synthesis-approach-for-carbon-nitrides-poly-triazine-imide-and-its-photocatalytic-properties
#18
Leonard Heymann, Björn Schiller, Heshmat Noei, Andreas Stierle, Christian Klinke
Poly(triazine imide) (PTI) is a material belonging to the group of carbon nitrides and has shown to have competitive properties compared to melon or g-C3 N4 , especially in photocatalysis. As most of the carbon nitrides, PTI is usually synthesized by thermal or hydrothermal approaches. We present and discuss an alternative synthesis for PTI which exhibits a pH-dependent solubility in aqueous solutions. This synthesis is based on the formation of radicals during electrolysis of an aqueous melamine solution, coupling of resulting melamine radicals and the final formation of PTI...
April 30, 2018: ACS Omega
https://www.readbyqxmd.com/read/29732447/high-resolution-adhesion-kinetics-of-egcg-exposed-tumor-cells-on-biomimetic-interfaces-comparative-monitoring-of-cell-viability-using-label-free-biosensor-and-classic-end-point-assays
#19
Beatrix Peter, Rita Ungai-Salanki, Bálint Szabó, Agoston G Nagy, Inna Szekacs, Szilvia Bősze, Robert Horvath
A high-throughput label-free resonant waveguide grating biosensor, the Epic BenchTop, was utilized to in situ monitor the adhesion process of cancer cells on Arg-Gly-Asp tripeptide displaying biomimetic polymer surfaces. Using highly adherent human cervical adenocarcinoma (HeLa) cells as a model system, cell adhesion kinetic data with outstanding temporal resolution were obtained. We found that pre-exposing the cells to various concentrations of the main extract of green tea, the (-)-epigallocatechin gallate (EGCG), largely affected the temporal evolution of the adhesion process...
April 30, 2018: ACS Omega
https://www.readbyqxmd.com/read/29732446/design-synthesis-and-biological-evaluations-of-asymmetric-bow-tie-pamam-dendrimer-based-conjugates-for-tumor-targeted-drug-delivery
#20
Tao Wang, Yaozhong Zhang, Longfei Wei, Yuhan G Teng, Tadashi Honda, Iwao Ojima
A unique asymmetric bow-tie poly(amidoamine) (PAMAM) dendrimer (ABTD) scaffold was designed and developed as a well-defined macromolecular carrier for tumor-targeted drug delivery. The ABTD scaffold in this study consists of a G3-half-dendron (G3-HD) unit and a G1-half-dendron (G1-HD) unit, bearing thiol moiety in each unit and a bis(maleimide) linker unit, which undergo sequential thiol-maleimide coupling to assemble the scaffold. This assembly methodology is applicable to all other combinations of different generations of PAMAM dendrimers...
April 30, 2018: ACS Omega
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