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https://www.readbyqxmd.com/read/29667839/polyoxometalate-based-metal-organic-frameworks-as-visible-light-induced-photocatalysts
#1
Xiuxia Zhao, Shaowei Zhang, Junqing Yan, Landong Li, Guangjun Wu, Wei Shi, Guangming Yang, Naijia Guan, Peng Cheng
Two stable 3D polyoxometalate-based metal-organic frameworks (PMOFs), [CuI 12 (trz)8 (H2 O)2 ][α-SiW12 O40 ]·2H2 O (1) and [CuI 12 (trz)8 Cl][α-PW12 O40 ] (2) (Htrz = 1- H-1,2,4-triazole) based on Keggin-type POMs were successfully obtained and fully characterized. The basic building units of the two PMOFs are [CuI 12 (trz)8 ], but polyoxoanion (POA) template effect leads to different structures and properties: 1 represents an interesting example that [α-SiW12 O40 ]4- locate in the nine-membered Cu-trz rings through Cu···O weak interactions to form a 3D framework, whereas 2 shows a 3D structure constructed from 2D bilayer cationic network [CuI 12 (trz)8 Cl]3+ and [α-PW12 O40 ]3- lying in the adjacent layers via Cu···O weak interactions...
April 18, 2018: Inorganic Chemistry
https://www.readbyqxmd.com/read/29667833/total-synthesis-of-l-156-373-and-an-oxopiz-analogue-via-a-submonomer-approach
#2
Yassin M Elbatrawi, Chang Won Kang, Juan R Del Valle
The first chemical synthesis of L-156,373 (1), a potent oxytocin receptor antagonist isolated from Streptomyces silvensis, is reported. Assembly of the unusual d-Piz-l-Piz dipeptide subunit was achieved through a sequential electrophilic amination-acylation-deprotection strategy followed by late-stage Piz ring formation. Synthesis and incorporation of a novel N-hydroxy-l-isoleucine building block is also described. This submonomer approach was further applied to the expedient synthesis of a di-δ-oxopiperazic acid analogue of 1 starting from Fmoc-Glu( tBu)-OH building blocks...
April 18, 2018: Organic Letters
https://www.readbyqxmd.com/read/29667832/synthesis-crystal-structure-and-the-deep-near-infrared-absorption-emission-of-bright-azabodipy-based-organic-fluorophores
#3
Wanle Sheng, Yayang Wu, Changjiang Yu, Petia Bobadova-Parvanova, Erhong Hao, Lijuan Jiao
Annularly fused azaBODIPY-based organic fluorophores (HBPs 2) containing up to 13 aromatic ring fusions were synthesized by a Suzuki coupling reaction with bromoazadipyrromethenes and a subsequent regioselective oxidative ring-fusion reaction. X-ray analysis indicates almost planar dipyrrin cores for all crystals but overall curved or "wave" conformations for those HBP dyes. These molecules exhibit unique structural and physical properties including excellent spectral selectivity (negligible absorption between 300 and 700 nm), sharp near-infrared (NIR) absorption (up to 878 nm) and emission (up to 907 nm), large extinction coefficient (up to 4...
April 18, 2018: Organic Letters
https://www.readbyqxmd.com/read/29667828/a-photorearrangement-to-construct-the-abde-tetracyclic-core-of-palau-amine
#4
Samuel Aubert-Nicol, Jean Lessard, Claude Spino
A synthesis of the ABDE tetracyclic carbon core of palau'amine was achieved in 9 steps from commercial materials. The core's most notable feature, a highly strained trans cyclopenta[ c]pyrrolidine, was obtained in high yield using a ring contraction strategy starting from a much less strained trans bicyclic lactam derivative that is accessible in only 7 steps.
April 18, 2018: Organic Letters
https://www.readbyqxmd.com/read/29667826/ruthenium-catalyzed-ring-opening-addition-of-anilides-to-7-azabenzonorbornadienes-a-diastereoselective-route-to-hydronaphthylamines
#5
Qiangqiang Yan, Chunhua Xiong, Steven Chu, Zhanxiang Liu, Yuhong Zhang
Ruthenium(II)-catalyzed direct ring-opening reaction of 7-azabenzonorbornadienes with anilides via C-H activation to access hydronaphthylamines has been developed. The transformation proceeds with high stereoselectivity to give cis-configuration products under redox-neutral conditions.
April 18, 2018: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29667825/structure-based-design-of-inhibitors-targeting-prfa-the-master-virulence-regulator-of-listeria-monocytogenes
#6
Martina Kulén, Marie Lindgren, Sabine Hansen, Andrew Gerard Cairns, Christin Grundström, Afshan Begum, Ingeborg van der Lingen, Kristoffer Brännström, Michael Hall, Uwe H Sauer, Jörgen Johansson, A Elisabeth Sauer-Eriksson, Fredrik Almqvist
Listeria monocytogenes is a bacterial pathogen that controls much of its virulence through the transcriptional regulator PrfA. In this study, we describe structure-guided design and synthesis of a set of PrfA inhibitors based on ring-fused 2-pyridone heterocycles. Our most effective compound decreased virulence factor expression, reduced bacterial uptake into eukaryotic cells, and improved survival of chicken embryos infected with L. monocytogenes compared to previously identified compounds. Crystal structures identified an intra-protein "tunnel" as the main inhibitor binding site (AI), where the compounds participate in an extensive hydrophobic network that restricts the protein's ability to form functional DNA-binding helix-turn-helix (HTH) motifs...
April 18, 2018: Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/29667675/pre-programmed-self-assembly-of-polynuclear-clusters
#7
Takuya Shiga, Graham N Newton, Hiroki Oshio
This perspective reviews our recent efforts towards the self-assembly of polynuclear clusters with ditopic and tritopic multidentate ligands HL1 (2-phenyl-4,5-bis{6-(3,5-dimethylpyrazol-1-yl)pyrid-2-yl}-1H-imidazole) and H2L2 (2,6-bis-[5-(2-pyridinyl)-1H-pyrazole-3-yl]pyridine), both of which are planar and rigid molecules. HL1 was found to be an excellent support for tetranuclear [Fe4] complexes, [FeII4(L1)4](BF4)4 ([FeII4]) and [FeIII2FeII2(L1)4](BF4)6 ([FeIII2FeII2]). The homovalent system was found to exhibit multistep spin crossover (SCO), while the mixed-valence [FeIII2FeII2] complex shows wavelength-dependent tuneable light-induced excited spin state trapping (LIESST)...
April 18, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29667579/intracellular-antibody-signalling-is-regulated-by-phosphorylation-of-the-fc-receptor-trim21
#8
Claire Dickson, Adam J Fletcher, Marina Vaysburd, Ji-Chun Yang, Donna L Mallery, Jingwei Zeng, Christopher M Johnson, Stephen H McLaughlin, Mark Skehel, Sarah Maslen, James Cruickshank, Nicolas Huguenin-Dezot, Jason W Chin, David Neuhaus, Leo C James
Cell surface Fc receptors activate inflammation and are tightly controlled to prevent autoimmunity. Antibodies also simulate potent immune signalling from inside the cell via the cytosolic antibody receptor TRIM21, but how this is regulated is unknown. Here we show that TRIM21 signalling is constitutively repressed by its B-Box domain and activated by phosphorylation. The B-Box occupies an E2 binding site on the catalytic RING domain by mimicking E2-E3 interactions, inhibiting TRIM21 ubiquitination and preventing immune activation...
April 18, 2018: ELife
https://www.readbyqxmd.com/read/29667067/a-first-in-class-inhibitor-mln4924-pevonedistat-induces-cell-cycle-arrest-senescence-and-apoptosis-in-human-renal-cell-carcinoma-by-suppressing-ube2m-dependent-neddylation-modification
#9
Bo Xu, Yuyou Deng, Ran Bi, Haoran Guo, Chang Shu, Neelam Kumari Shah, Junliang Chang, Guanchen Liu, Yujun Du, Wei Wei, Chunxi Wang
PURPOSE: MLN4924 is a second-generation inhibitor that targets ubiquitin-proteasome system by inhibiting neddylation activation enzyme (NAE), and subsequently blocking the neddylation-dependent activation of Cullin-RING E3 ligases (CRLs), which leads to the accumulation of CRLs substrates and hence, suppressing diverse tumor development. In this study, we investigated the potential application of this first-in-class inhibitor MLN4924 in the treatment of human renal cell carcinoma both in vitro and in vivo...
April 17, 2018: Cancer Chemotherapy and Pharmacology
https://www.readbyqxmd.com/read/29666937/biomedical-approaches-to-hiv-prevention-in-women
#10
REVIEW
Christine L Heumann
PURPOSE OF REVIEW: Effective HIV prevention techniques for women are of critical importance, as nearly half of all HIV infections globally are in women. This article reviews the recent literature on biomedical approaches to HIV prevention in women. RECENT FINDINGS: In trials in which women were adherent to oral pre-exposure prophylaxis (PrEP), PrEP was equally efficacious in men and women. However, in studies of oral PrEP exclusively in women, adherence was low, and it was not efficacious...
April 17, 2018: Current Infectious Disease Reports
https://www.readbyqxmd.com/read/29666865/preparation-of-lactic-acid-and-glucose-responsive-poly-%C3%AE%C2%B5-caprolactone-b-poly-ethylene-oxide-block-copolymer-micelles-using-phenylboronic-ester-as-a-sensitive-block-linkage
#11
David Vrbata, Mariusz Uchman
The present study describes the synthesis, self-assembly and responsiveness to glucose and lactic acid of biocompatible and biodegradable block copolymer micelles using phenylboronic ester as the linkage between hydrophobic poly(ε-caprolactone) (PCL) and hydrophilic poly(ethylene oxide) (PEO). The PCL block with pendant phenylboronic acid (PCLBA) was synthesized by combining ε-caprolactone (ε-CL) ring-opening polymerisation (ROP), using 4-hydroxymethyl(phenylboronic) acid pinacolate as the initiator, and pinacol deprotection...
April 18, 2018: Nanoscale
https://www.readbyqxmd.com/read/29666548/inhibitory-effect-of-soy-saponins-on-the-activity-of-%C3%AE-lactamases-including-new-delhi-metallo-%C3%AE-lactamase-1
#12
Hitoshi Horie, Asuka Chiba, Shigeo Wada
β-Lactamase-producing bacteria encode enzymes that inactivate β-lactam antibiotics by catalyzing the hydrolysis of the β-lactam ring. Crude soy saponins were observed to have synergistic effects on the antimicrobial activity of β-lactam antibiotics against β-lactamase-producing Staphylococcus aureus strains. Furthermore, the activities of β-lactamases derived from Enterobacter cloacae , Escherichia coli , and S. aureus were decreased significantly in the presence of crude soy saponins. This inhibitory effect was also observed against the New Delhi metallo-β-lactamase 1 (NDM-1), an enzyme whose activity is not inhibited by the current β-lactamase inhibitors...
May 2018: Journal of Food Science and Technology
https://www.readbyqxmd.com/read/29666034/contraceptive-use-effectiveness-and-pregnancy-prevention-information-preferences-among-heterosexual-and-sexual-minority-college-women
#13
Heather D Blunt-Vinti, Erika L Thompson, Stacey B Griner
BACKGROUND: Previous research shows that sexual minority women have higher rates of unintended pregnancy than heterosexual women, but has not considered the wide range of contraceptive method effectiveness when exploring this disparity. We examine contraceptive use effectiveness and desire for pregnancy prevention information among college women across sexual orientation identity as a risk factor for unintended pregnancy. METHODS: Using the National College Health Assessment Fall-2015 dataset, restricted to women who reported engaging in vaginal sex and not wanting to be pregnant (N = 6,486), logistic regression models estimated the odds of contraceptive method effectiveness and desire for pregnancy prevention information by sexual orientation...
April 14, 2018: Women's Health Issues: Official Publication of the Jacobs Institute of Women's Health
https://www.readbyqxmd.com/read/29665962/the-degradation-of-three-ringed-polycyclic-aromatic-hydrocarbons-by-wood-inhabiting-fungus-pleurotus-ostreatus-and-soil-inhabiting-fungus-agaricus-bisporus
#14
Natalia Pozdnyakova, Ekaterina Dubrovskaya, Marina Chernyshova, Oleg Makarov, Sergey Golubev, Svetlana Balandina, Olga Turkovskaya
The degradation of two isomeric three-ringed polycyclic aromatic hydrocarbons by the white rot fungus Pleurotus ostreatus D1 and the litter-decomposing fungus Agaricus bisporus F-8 was studied. Despite some differences, the degradation of phenanthrene and anthracene followed the same scheme, forming quinone metabolites at the first stage. The further fate of these metabolites was determined by the composition of the ligninolytic enzyme complexes of the fungi. The quinone metabolites of phenanthrene and anthracene produced in the presence of only laccase were observed to accumulate, whereas those formed in presence of laccase and versatile peroxidase were metabolized further to form products that were further included in basal metabolism (e...
May 2018: Fungal Biology
https://www.readbyqxmd.com/read/29665556/preparation-of-wheat-straw-supported-nanoscale-zero-valent-iron-and-its-removal-performance-on-ciprofloxacin
#15
Yingying Shao, Pin Zhao, Qinyan Yue, Yuwei Wu, Baoyu Gao, Wenjia Kong
Wheat straw-supported Nanoscale Zero-Valent Iron particles (WS-NZVI) were successfully synthesized, which were used for Ciprofloxacin hydrochloride (CIP) removal in simulation wastewater. The structure, chemical composition and micro-morphology of WS-NZVI and Nanoscale Zero-Valent Iron (NZVI) were characterized by scanning electron microscopy analysis (SEM), X-ray diffraction (XRD), as well as the Fourier Transformed IR spectra (FT-IR). XRD results proved the existence of Fe°, and SEM images indicated that the agglomeration of NZVI was effectively inhibited when loaded on wheat straw...
April 14, 2018: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/29665476/bioactive-norditerpenoids-from-cephalotaxus-fortunei-var-alpina-and-c-lanceolata
#16
Ling Ni, Xiu-Hong Zhong, Xiao-Jiao Chen, Bing-Jie Zhang, Mei-Fen Bao, Xiang-Hai Cai
Twenty-eight naturally occurring Cephalotaxus tropone analogues, including 19 previously undescribed ones, were identified from Cephalotaxus fortunei Hook. var. alpina H. L. Li and C. lanceolata K. M. Feng. The presence of the C20 cephinoids A-E revealed that these tropones were assigned to the norditerpenoids and were perhaps derived from labdane-type diterpenoids. These norditerpenoids showed excellent cytotoxicity against human cancer cells (IC50 , 20-0.1 μM) in vitro. The SAR (structure-activity relationship) analysis disclosed that the tropone moiety and the lactone ring were crucial structural features for the observed activities...
April 14, 2018: Phytochemistry
https://www.readbyqxmd.com/read/29665440/mri-compatible-ms2-nanoparticles-designed-to-cross-the-blood-brain-barrier-providing-a-path-towards-tinnitus-treatment
#17
Aaron K Apawu, Stephanie M Curley, Angela R Dixon, Mirabela Hali, Moaz Sinan, Rod D Braun, James Castracane, Anthony T Cacace, Magnus Bergkvist, Avril Genene Holt
Fundamental challenges of targeting specific brain regions for treatment using pharmacotherapeutic nanoparticle (NP) carriers include circumventing the blood-brain-barrier (BBB) and tracking delivery. Angiopep-2 (AP2) has been shown to facilitate the transport of large macromolecules and synthetic nanoparticles across the BBB. Thus, conjugation of AP2 to an MS2 bacteriophage based NP should also permit transport across the BBB. We have fabricated and tested a novel MS2 capsid-based NP conjugated to the ligand AP2...
April 14, 2018: Nanomedicine: Nanotechnology, Biology, and Medicine
https://www.readbyqxmd.com/read/29665369/defective-rna-particles-derived-from-tomato-black-ring-virus-genome-interfere-with-the-replication-of-parental-virus
#18
Beata Hasiów-Jaroszewska, Julia Minicka, Aleksandra Zarzyńska-Nowak, Daria Budzyńska, Santiago F Elena
Tomato black ring virus (TBRV) is the only member of the Nepovirus genus that is known to form defective RNA particles (D RNAs) during replication. Here, de novo generation of D RNAs was observed during prolonged passages of TBRV isolates originated from Solanum lycopersicum and Lactuca sativa in Chenopodium quinoa plants. D RNAs of about 500 nt derived by a single deletion in the RNA1 molecule and contained a portion of the 5' untranslated region and viral replicase, and almost the entire 3' non-coding region...
April 14, 2018: Virus Research
https://www.readbyqxmd.com/read/29665353/tripartite-motif-31-promotes-resistance-to-anoikis-of-hepatocarcinoma-cells-through-regulation-of-p53-ampk-axis
#19
Pengbo Guo, Yumin Qiu, Xiaomin Ma, Tao Li, Xiaoxiao Ma, Lihui Zhu, Yueke Lin, Lihui Han
Anoikis-resistance is an essential feature of cancer cells to obtain successful metastasis, whereas the molecular mechanism involved in this process of hepatocellular carcinoma (HCC) cells is not fully understood. Here we demonstrated that tripartite motif-containing (TRIM) 31, a new member of the TRIM family, was significantly upregulated in the anchorage-deprived HCC cells compared with their attached counterpart. When we blocked TRIM31 expression by its specific interference RNAs, the anoikis-resistance of HCC cells was significantly reversed...
April 14, 2018: Experimental Cell Research
https://www.readbyqxmd.com/read/29665317/encapsulation-and-release-of-functional-nanodroplets-entrapped-in-nanofibers
#20
Kusuma Thongchaivetcharat, Ratchapol Jenjob, Daniel Crespy
A method is presented for preserving the structural integrity of nanodroplets produced by emulsification. Droplets of different hydrophobic liquids such as essential oils or monomers are produced by the miniemulsion process. The miniemulsions are then electrospun to yield dextran nanofibers entrapping the hydrophobic nanodroplets. The nanodroplets are then successfully redispersed by dissolving the nanofibers in water. Furthermore, it is shown that nanofibers can be used to store a monomer and a catalyst as healing agents for ring-opening metathesis polymerization...
April 17, 2018: Small
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