keyword
MENU ▼
Read by QxMD icon Read
search

Precursor

keyword
https://www.readbyqxmd.com/read/27911492/rolling-circle-amplification-with-chemically-modified-nucleoside-triphosphates
#1
Marcel Hollenstein, Masad J Damha
Modified nucleoside triphosphates (dN*TPs) represent facile and versatile precursors for the introduction of chemical diversity into nucleic acids. While dN*TPs have been utilized in a plethora of practical applications, very little attention has been devoted to the assessment of their compatibility with isothermal amplification strategies. In this context, rolling circle amplification (RCA) is a wide-spread enzymatic replication method in which small single-stranded DNA (ssDNA) circles serve as templates in primer extension reactions yielding very long, ssDNA products...
December 1, 2016: Current Protocols in Nucleic Acid Chemistry
https://www.readbyqxmd.com/read/27911484/platinum-complex-assemblies-as-luminescent-probes-and-tags-for-drugs-and-toxins-in-water
#2
Stephan Sinn, Frank Biedermann, Luisa De Cola
A reactive phosphorescent probe for aza-heterocyclic drugs and toxins was developed, affording a supramolecular emission-switch-on chemosensor in water. Complex formation of the heterocycles with a platinum(II) precursor proceeds readily at ambient conditions, allowing for facile analyte screening. 52 structurally diverse compounds were tested, out of which 23 pyridines, imidazole, and triazoles formed strongly emissive complex aggregates. Importantly, they all can be clearly distinguished from each other through a principal component analysis, but often already by simple visual inspection, e...
December 1, 2016: Chemistry: a European Journal
https://www.readbyqxmd.com/read/27911418/synthesis-and-characterization-of-fe-doped-aluminosilicate-nanotubes-with-enhanced-electron-conductive-properties
#3
Ehsan Shafia, Serena Esposito, Elnaz Bahadori, Marco Armandi, Maela Manzoli, Barbara Bonelli
The goal of the protocol is to synthesize Fe-doped aluminosilicate nanotubes of the imogolite type with the formula (OH)3Al2-xFexO3SiOH. Doping with Fe aims at lowering the band gap of imogolite, an insulator with the chemical formula (OH)3Al2O3SiOH, and at modifying its adsorption properties towards azo-dyes, an important class of organic pollutants of both wastewater and groundwater. Fe-doped nanotubes are obtained in two ways: by direct synthesis, where FeCl3 is added to an aqueous mixture of the Si and Al precursors, and by post-synthesis loading, where preformed nanotubes are put in contact with a FeCl3•6H2O aqueous solution...
November 15, 2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/27911403/preparation-and-reactivity-of-a-triphosphenium-bromide-salt-a-convenient-and-stable-source-of-phosphorus-i
#4
Stephanie C Kosnik, Justin F Binder, Maxemilian C Nascimento, Charles L B Macdonald
We present herein the optimized synthesis of a triphosphenium bromide salt. Apart from being a versatile metathesis reagent, this unusually stable low-valent-phosphorus-containing compound acts as a useful P(+) transfer agent. Unlike traditional methods employed to access low-coordinate phosphorus species which usually require pyrophoric phosphorus-containing precursors (white phosphorus, Tris(trimethylsilyl)phosphine, etc.), or harsh reducing agents (alkali metals, potassium graphite, etc.), the current approach does not involve pyrophoric or explosive reagents and can be done on large scales (>20 g) in excellent yields by undergraduates with basic air-free synthetic training...
November 22, 2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/27911326/localization-and-processing-of%C3%A2-the%C3%A2-amyloid-%C3%AE-protein-precursor-in%C3%A2-mitochondria-associated-membranes
#5
Dolores Del Prete, Jan M Suski, Bénédicte Oulès, Delphine Debayle, Anne Sophie Gay, Sandra Lacas-Gervais, Renaud Bussiere, Charlotte Bauer, Paolo Pinton, Patrizia Paterlini-Bréchot, Mariusz R Wieckowski, Frédéric Checler, Mounia Chami
Alteration of mitochondria-associated membranes (MAMs) has been proposed to contribute to the pathogenesis of Alzheimer's disease (AD). We studied herein the subcellular distribution, the processing, and the protein interactome of the amyloid-β protein precursor (AβPP) and its proteolytic products in MAMs. We reveal that AβPP and its catabolites are present in MAMs in cellular models overexpressing wild type AβPP or AβPP harboring the double Swedish or London familial AD mutations, and in brains of transgenic mice model of AD...
November 26, 2016: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/27911305/nitrosylation-of-vesicular-transporters-in-brain-of-amyloid-precursor-protein-presenilin-1-double-transgenic-mice
#6
Ying Wang, Zhu Zhou, Hua Tan, Shenghua Zhu, Yiran Wang, Yingxia Sun, Xin-Min Li, Jun-Feng Wang
Nitric oxide can attack thiol groups of cysteine residues in proteins and induce protein cysteine S-nitrosylation. Cholinergic and glutamatergic systems are dysregulated in Alzheimer's disease. Vesicular acetylcholine transporter (VAChT) and vesicular glutamate transporter 1 (VGLUT1) are important in packaging acetylcholine and glutamate into vesicles, which is an important step for neurotransmission. Previously we found that VAChT and VGLUT1 can be nitrosylated and that S-nitrosylation of these transporters inhibits vesicular uptake of acetylcholine and glutamate...
November 26, 2016: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/27911303/amylin-treatment-reduces-neuroinflammation-and-ameliorates-abnormal-patterns-of-gene-expression-in%C3%A2-the-cerebral-cortex-of-an-alzheimer-s-disease-mouse-model
#7
Erming Wang, Haihao Zhu, Xiaofan Wang, Adam Gower, Max Wallack, Jan Krzysztof Blusztajn, Neil Kowall, Wei Qiao Qiu
Our recent study has demonstrated that peripheral amylin treatment reduces the amyloid pathology in the brain of Alzheimer's disease (AD) mouse models, and improves their learning and memory. We hypothesized that the beneficial effects of amylin for AD was beyond reducing the amyloids in the brain, and have now directly tested the actions of amylin on other aspects of AD pathogenesis, especially neuroinflammation. A 10-week course of peripheral amylin treatment significantly reduced levels of cerebral inflammation markers, Cd68 and Iba1, in amyloid precursor protein (APP) transgenic mice...
November 28, 2016: Journal of Alzheimer's Disease: JAD
https://www.readbyqxmd.com/read/27911037/decoding-the-molecular-basis-for-the-population-mechanism-of-the-triplet-phototoxic-precursors-in-uva-light-activated-pyrimidine-anticancer-drugs
#8
Lara Martínez-Fernández, Giovanni Granucci, Marvin Pollum, Carlos Crespo-Hernández, Maurizio Persico, Ines Corral Perez
Photosensitization of DNA by thionucleosides is a promising photo-chemotherapeutic treatment option for a variety of malignancies. DNA metabolization of thiated prodrugs can lead to cell death upon exposure to a low dose of UVA light. The exact mechanisms of thionucleoside phototoxicity are still not fully understood. In this work, we have combined femtosecond broadband transient absorption experiments with state-of-the-art molecular simulations to provide mechanistic insights for the ultrafast and efficient population of the triplet-state in the UVA-activated pyrimidine anticancer drug: 4-thiothymine...
December 2, 2016: Chemistry: a European Journal
https://www.readbyqxmd.com/read/27911033/regioselective-synthesis-of-%C3%AE-fluorinated-cyclopentenones-via-organocatalytic-difluorocyclopropanation-and-fluorine-directed-and-activated-nazarov-cyclization
#9
Kohei Fuchibe, Ryo Takayama, Takaharu Yokoyama, Junji Ichikawa
Silyl dienol ethers, prepared from α,β-unsaturated ketones, underwent proton sponge-catalyzed difluorocyclopropanation with trimethylsilyl 2,2-difluoro-2-fluorosulfonylacetate (TFDA) in a regioselective manner, leading to 1,1-difluoro-2-siloxy-2-vinylcyclopropanes in good yields. The cyclopropanes thus obtained were in turn subjected to fluoride ion-catalyzed ring opening to afford 1-fluorovinyl vinyl ketones (i.e., Nazarov precursors). Treatment of the precursors with Me3Si+ B(OTf)4- regioselectively promoted the Nazarov cyclization, whose rate and regioselectivity were drastically enhanced by the fluorine substituent, thereby facilitating efficient synthesis of biologically promising α-fluorocyclopentenone derivatives...
December 2, 2016: Chemistry: a European Journal
https://www.readbyqxmd.com/read/27910979/efficient-synthesis-of-cysteine-rich-cyclic-peptides-through-intramolecular-native-chemical-ligation-of-n-hnb-cys-peptide-crypto-thioesters
#10
Victor P Terrier, Agnès F Delmas, Vincent Aucagne
We herein introduce a straightforward synthetic route to cysteine-containing cyclic peptides based on the intramolecular native chemical ligation of in situ generated thioesters. Key precursors are N-Hnb-Cys crypto-thioesters, easily synthesized by Fmoc-based SPPS. The strategy is applied to a representative range of naturally occurring cyclic disulfide-rich peptide sequences.
December 2, 2016: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/27910971/synthesis-engineering-of-iron-oxide-raspberry-shaped-nanostructures
#11
O Gerber, B P Pichon, D Ihiawakrim, I Florea, S Moldovan, O Ersen, D Begin, J-M Grenèche, S Lemonnier, E Barraud, S Begin-Colin
Magnetic porous nanostructures consisting of oriented aggregates of iron oxide nanocrystals display very interesting properties such as a lower oxidation state of magnetite, and enhanced saturation magnetization in comparison with individual nanoparticles of similar sizes and porosity. However, the formation mechanism of these promising nanostructures is not well understood, which hampers the fine tuning of their magnetic properties, for instance by doping them with other elements. Therefore the formation mechanism of porous raspberry shaped nanostructures (RSNs) synthesized by a one-pot polyol solvothermal method has been investigated in detail from the early stages by using a wide panel of characterization techniques, and especially by performing original in situ HR-TEM studies in temperature...
December 2, 2016: Nanoscale
https://www.readbyqxmd.com/read/27910345/heat-flux-estimates-of-power-balance-on-proto-mpex-with-ir-imaging
#12
M Showers, T M Biewer, J B O Caughman, D C Donovan, R H Goulding, J Rapp
The Prototype Material Plasma Exposure eXperiment (Proto-MPEX) at Oak Ridge National Laboratory (ORNL) is a precursor linear plasma device to the Material Plasma Exposure eXperiment (MPEX), which will study plasma material interactions (PMIs) for future fusion reactors. This paper will discuss the initial steps performed towards completing a power balance on Proto-MPEX to quantify where energy is lost from the plasma, including the relevant diagnostic package implemented. Machine operating parameters that will improve Proto-MPEX's performance may be identified, increasing its PMI research capabilities...
November 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27910233/a-genetically-encoded-allysine-for-the-synthesis-of-proteins-with-site-specific-lysine-dimethylation
#13
Zhipeng A Wang, Yu Zeng, Yadagiri Kurra, Xin Wang, Jeffery M Tharp, Erol C Vatansever, Willie W Hsu, Susie Dai, Xinqiang Fang, Wenshe R Liu
Using the amber suppression approach, N(ϵ) -(4-azidobenzoxycarbonyl)-δ,ϵ-dehydrolysine, an allysine precursor is genetically encoded in E. coli. Its genetic incorporation followed by two sequential biocompatible reactions allows convenient synthesis of proteins with site-specific lysine dimethylation. Using this approach, dimethyl-histone H3 and p53 proteins have been synthesized and used to probe functions of epigenetic enzymes including histone demethylase LSD1 and histone acetyltransferase Tip60. We confirmed that LSD1 is catalytically active toward H3K4me2 and H3K9me2 but inert toward H3K36me2, and methylation at p53 K372 directly activates Tip60 for its catalyzed acetylation at p53 K120...
December 2, 2016: Angewandte Chemie
https://www.readbyqxmd.com/read/27910132/a-simple-method-for-preparation-of-pure-68-ga-acetate-precursor-for-formulation-of-radiopharmaceuticals-physicochemical-characteristics-of-the-68-ga-eluate-of-the-sno2-based-68-ge-68-ga-column-generator
#14
Sankha Chattopadhyay, Md Neyar Alam, Madhu Smita, Umesh Kumar, Sujata Saha Das, Luna Barua
Gallium-68 radioisotope is an excellent source in clinical positron emission tomography application due to its ease of availability from germanium-68 ((68) Ge)/gallium-68 ((68) Ga) generator having a shelf life of 1 year. In this paper, a modified method for purification of the primary eluate of (68) Ge-(68) Ga generator by using a small cation exchange resin (Dowex-50) column has been described. The breakthrough of (68) Ge before and after purification of (68) Ga eluate was 0.014% and 0.00027%, respectively...
December 1, 2016: Journal of Labelled Compounds & Radiopharmaceuticals
https://www.readbyqxmd.com/read/27910065/pathology-of-endometrial-carcinoma
#15
Sigurd F Lax
On a clinicopathological and molecular level, two distinctive types of endometrial carcinoma, type I and type II, can be distinguished. Endometrioid carcinoma, the typical type I carcinoma, seems to develop through an estrogen-driven "adenoma carcinoma" pathway from atypical endometrial hyperplasia/endometrioid intraepithelial neoplasia (AEH/EIN). It is associated with elevated serum estrogen and high body mass index and expresses estrogen and progesterone receptors. They are mostly low grade and show a favorable prognosis...
2017: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/27910063/epidemiology-of-endometrial-carcinoma-etiologic-importance-of-hormonal-and-metabolic-influences
#16
Ashley S Felix, Hannah P Yang, Daphne W Bell, Mark E Sherman
Endometrial carcinoma is the most common gynecologic cancer in developed nations, and the annual incidence is projected to increase, secondary to the high prevalence of obesity, a strong endometrial carcinoma risk factor. Although endometrial carcinomas are etiologically, biologically, and clinically diverse, hormonal and metabolic mechanisms are particularly strongly implicated in the pathogenesis of endometrioid carcinoma, the numerically predominant subtype. The centrality of hormonal and metabolic disturbances in the pathogenesis of endometrial carcinoma, combined with its slow development from well-characterized precursors in most cases, offers a substantial opportunity to reduce endometrial carcinoma mortality through early detection, lifestyle modification, and chemoprevention...
2017: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/27910046/exosomes-based-gene-therapy-for-microrna-delivery
#17
Prabhu Mathiyalagan, Susmita Sahoo
Despite recent advances in scientific knowledge and clinical practice, cardiovascular disease management and treatment remain a major burden. While several treatment strategies using drugs and surgeries are being developed for cardiovascular manifestations, gene-based therapies hold significant promise. Recent findings from our laboratory unveiled a novel mechanism that exosomes, secreted nanovesicles from stem cells, mediate cardiac repair via transferring their unique repertoire of microRNAs (miRNA) to recipient cells in the heart...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/27909970/over-expression-of-mir158-causes-pollen-abortion-in-brassica-campestris-ssp-chinensis
#18
Zhiming Ma, Jianxia Jiang, Ziwei Hu, Tianqi Lyu, Yang Yang, Jingjing Jiang, Jiashu Cao
We identified and cloned the two precursors of miR158 and its target gene in Brassica campestris ssp. chinensis, which both had high relative expression in the inflorescences. Further study revealed that over-expression of miR158 caused reduced pollen varbility, which was caused by the degradation of pollen contents from the binucleate microspore stage. These results first suggest the role of miR158 in pollen development of Brassica campestris ssp. chinensis. MicroRNAs (miRNAs) play crucial roles in many important growth and development processes both in plants and animals by regulating the expression of their target genes via mRNA cleavage or translational repression...
December 1, 2016: Plant Molecular Biology
https://www.readbyqxmd.com/read/27909900/obesity-and-colorectal-cancer
#19
Carmen Jochem, Michael Leitzmann
There is strong evidence that modifiable lifestyle factors such as obesity play a key role in colorectal carcinogenesis. Epidemiologic data have consistently reported a positive association between obesity and colorectal cancer. The relative risk associated with general obesity (as assessed by BMI) is higher in men than in women and for cancer of the colon than for cancer of the rectum. Abdominal obesity (as assessed by waist circumference (WC) or waist-to-hip ratio) is associated with an increased risk of colorectal cancer in both sexes, with stronger associations for cancer of the colon than for cancer of the rectum...
2016: Recent Results in Cancer Research
https://www.readbyqxmd.com/read/27909808/clinical-validation-of-a-novel-urine-based-metabolomic-test-for-the-detection-of-colonic-polyps-on-chinese-population
#20
Lu Deng, Hong Fang, Victor K Tso, Yuanyuan Sun, Rae R Foshaug, Spencer C Krahn, Fen Zhang, Yujie Yan, Huilin Xu, David Chang, Yong Zhang, Richard N Fedorak
PURPOSE: Colorectal cancer is the fifth leading cause of cancer-related deaths in China. When detected early, with the removal of adenomatous polyps, precursors of colorectal cancer, it is preventable. The aim of this study was to evaluate a novel urine-based metabolomic diagnostic test for the detection of adenomatous polyps, PolypDx™, that was originally developed and validated using 1000 samples from Canadian Cohort, on Chinese population. METHODS: Prospective urine samples were collected from 1000 participants undergoing colonoscopy examination, from March 2013 to July 2014 at Minhang District, Shanghai Centre for Disease Control and Prevention...
December 1, 2016: International Journal of Colorectal Disease
keyword
keyword
112583
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"