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https://www.readbyqxmd.com/read/29793196/seasonal-cycles-of-secondary-organic-aerosol-tracers-in-rural-guangzhou-southern-china-the-importance-of-atmospheric-oxidants
#1
Qi Yuan, Senchao Lai, Junwei Song, Xiang Ding, Lishan Zheng, Xinming Wang, Yan Zhao, Junyu Zheng, Dingli Yue, Liuju Zhong, Xiaojun Niu, Yingyi Zhang
Thirteen secondary organic aerosol (SOA) tracers of isoprene (SOAI ), monoterpenes (SOAM ), sesquiterpenes (SOAS ) and aromatics (SOAA ) in fine particulate matter (PM2.5 ) were measured at a Pearl River Delta (PRD) regional site for one year. The characteristics including their seasonal cycles and the factors influencing their formation in this region were studied. The seasonal patterns of SOAI , SOAM and SOAS tracers were characterized over three enhancement periods in summer (I), autumn (II) and winter (III), while the elevations of SOAA tracer (i...
May 21, 2018: Environmental Pollution
https://www.readbyqxmd.com/read/29793109/17%C3%AE-estradiol-as-precursors-of-cl-br-dbps-in-the-disinfection-process-of-different-water-samples
#2
Yanan Shao, Zihan Pan, Chuan Rong, Yinghui Wang, Hongxiang Zhu, Yuanyuan Zhang, Kefu Yu
During chlorine disinfection process, reactions between the disinfectant and 17β-estradiol (E2) lead to the formation of halogenated disinfection byproducts (DBPs) which can be a risk to both ecosystem and human health. The degradation and transformation products of E2 in sodium hypochlorite (NaClO) disinfection processes of different water samples were investigated. The reaction kinetics research showed that the degradation rates of E2 were considerably dependent on the initial pH value and the types of water samples...
May 21, 2018: Environmental Pollution
https://www.readbyqxmd.com/read/29792960/hybrid-chitosan-tio-2-zns-prepared-under-mild-conditions-with-visible-light-driven-photocatalytic-activity
#3
A Jbeli, A M Ferraria, A M Botelho do Rego, S Boufi, S Bouattour
Thin films of chitosan (CS) coated on glass substrates were used as support for the immobilization of nanostructures TiO2 /ZnS via a mild chemical process followed by a hydrothermal treatment at 90 °C. The preparation route involved the coating of the CS film on the glass substrate followed by the deposition of a thin layer of Ti(OBu)4 precursor and immersion in a solution of Zn(O2 CCH3 )2 and Na2 S. After a hydrothermal treatment at 90 °C, an even layer of TiO2 anatase decorated by ZnS nanorods was generated...
May 21, 2018: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29792932/cystine-glutamate-transporter-system-x-c-is-involved-in-nitric-oxide-production-in-mouse-peritoneal-macrophages
#4
Sho Kobayashi, Shinji Hamashima, Takujiro Homma, Mami Sato, Ryosuke Kusumi, Shiro Bannai, Junich Fujii, Hideyo Sato
The amino acid transport system xc - is important for maintaining intracellular glutathione levels and extracellular redox balance. The main component of system xc - , xCT, is strongly induced by various stimuli, including oxidative stress and bacterial lipopolysaccharides (LPS) in macrophages. In the present study, we investigated the production of nitric oxide by LPS-stimulated mouse peritoneal macrophages isolated from both xCT-deficient and wild-type mice. After culturing macrophages in the presence of LPS for 24-48 h, nitrite levels in the medium of xCT-deficient macrophages were significantly decreased compared to that of wild-type cells...
May 21, 2018: Nitric Oxide: Biology and Chemistry
https://www.readbyqxmd.com/read/29792854/bergmann-glial-sonic-hedgehog-signaling-activity-is-required-for-proper-cerebellar-cortical-expansion-and-architecture
#5
Frances Y Cheng, Jonathan T Fleming, Chin Chiang
Neuronal-glial relationships play a critical role in the maintenance of central nervous system architecture and neuronal specification. A deeper understanding of these relationships can elucidate cellular cross-talk capable of sustaining proper development of neural tissues. In the cerebellum, cerebellar granule neuron precursors (CGNPs) proliferate in response to Purkinje neuron-derived Sonic hedgehog (Shh) before ultimately exiting the cell cycle and migrating radially along Bergmann glial fibers. However, the function of Bergmann glia in CGNP proliferation remains not well defined...
May 21, 2018: Developmental Biology
https://www.readbyqxmd.com/read/29792699/water-soluble-ruthenium-ii-carbonyls-with-1-3-5-triaza-7-phosphoadamantane
#6
Federica Battistin, Gabriele Balducci, Barbara Milani, Enzo Alessio
As a continuation of our strategy for preparing new Ru(II) precursors with improved water solubility through the introduction of highly water-soluble 1,3,5-triaza-7-phosphoadamantane (PTA) supporting ligands in the coordination sphere, in this work, we address the largely unexplored preparation of Ru(II)-PTA carbonyls. Two complementary synthetic approaches were used: (1) the treatment of a series of neutral Ru(II)-CO-dmso compounds of general formula RuCl2 (CO) n (dmso)4- n ( n = 1-3, 1-5) with PTA; (2) the reaction of Ru(II)-PTA complexes with CO...
May 24, 2018: Inorganic Chemistry
https://www.readbyqxmd.com/read/29792693/a-titanium-oxo-cluster-model-study-of-synergistic-effect-of-co-coordinated-dye-ligands-on-photocurrent-responses
#7
Jin-Le Hou, Peng Huo, Zheng-Zhen Tang, Li-Na Cui, Qin-Yu Zhu, Jie Dai
The use of multiple sensitizers in dye sensitized solar cells has been attractive as a promising way to achieve highly efficient photovoltaic performance. However, except for the complementary absorption, synergistic effects among the dye components have not been well understood. Herein, using ferrocene-1-carboxylate (FcCO2 ) and catechol (Cat) as dye ligands, two titanium oxo clusters (TOCs), [Ti3 O(Oi Pr)6 (Cat)(FcCO2 )2 ] (1) and [Ti7 O4 (Oi Pr)8 (Cat)5 (FcCO2 )2 ] (2), were synthesized and structurally characterized...
May 24, 2018: Inorganic Chemistry
https://www.readbyqxmd.com/read/29792692/small-molecule-targeted-recruitment-of-a-nuclease-to-rna
#8
Matthew G Costales, Yasumasa Matsumoto, Sai Pradeep Velagapudi, Matthew D Disney
The choreography between RNA synthesis and degradation is a key determinant in biology. Engineered systems such as CRISPR have been developed to rid a cell of RNAs. Here, we show that a small molecule can recruit a nuclease to a specific transcript, triggering its destruction. A small molecule that selectively binds the oncogenic microRNA(miR)-96 hairpin precursor was appended with a short 2'-5' poly(A) oligonucleotide. The conjugate locally activated endogenous, latent ribonuclease (RNase L), which selectively cleaved the miR-96 precursor in cancer cells in a catalytic and sub-stoichiometric fashion...
May 24, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29792683/top-down-deep-sequencing-of-ubiquitin-using-two-dimensional-mass-spectrometry
#9
Federico Floris, Lionel Chiron, Alice Lynch, Mark P Barrow, Marc-André Delsuc, Peter B O'Connor
Two-dimensional Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (2D FT-ICR MS or 2D MS) allows data independent fragmentation of all ions in a sample, and correlation of fragment ions to their precursors without isolation prior to fragmentation. Developments in computer capabilities and implementations in FTMS over of the last decade have allowed the technique to become a useful analytical tool for bottom-up proteomics (BUP), and more recently in top-down protein analysis (TDP). In this work, a new method of TDP is developed using two-dimensional mass spectrometry, called MS/2D FT-ICR MS or MS/2DMS...
May 24, 2018: Analytical Chemistry
https://www.readbyqxmd.com/read/29792422/toward-total-synthesis-of-thiolate-protected-metal-nanoclusters
#10
Qiaofeng Yao, Tiankai Chen, Xun Yuan, Jianping Xie
Total synthesis, where desired organic- and/or biomolecules could be produced from simple precursors at atomic precision and with known step-by-step reactions, has prompted centuries-lasting bloom of organic chemistry since its conceptualization in 1828 (Wöhler synthesis of urea). Such expressive science is also highly desirable in nanoscience, since it represents a decisive step toward atom-by-atom customization of nanomaterials for basic and applied research. Although total synthesis chemistry is less established in nanoscience, recent years have witnessed seminal advances and increasing research efforts devoted into this field...
May 24, 2018: Accounts of Chemical Research
https://www.readbyqxmd.com/read/29792344/direct-formylation-of-2-pyridone-core-of-3-n-methylcytisine-via-duff-reaction-synthesis-of-9-enyl-9-ynyl-and-9-imino-derivatives
#11
Polina R Petrova, Alena V Koval'skaya, Alexander N Lobov, Inna P Tsypysheva
The first direct synthesis of 3-N-methyl-9-formylcytisine via electrophylic formylation is described. It is established, that Vilsmeier-Haack and Gatterman variants of this reaction are unsuccessful in the case with 3-substituted (-)-cytisine derivatives, but Duff procedure (with hexamethylenetetramine in trifluoroacetic acid) gives a possibility to obtain the target pseudo aromatic aldehyde with the 69% yield. Convenient precursors for [4 + 2]- or [3 + 2]-cycloaddition reactions are obtained by means of condensation of synthesized 3-N-methyl-9-formylcytisine with acetone, nitromethane and phosphorous ylides with yields from 70 to 87%...
May 24, 2018: Natural Product Research
https://www.readbyqxmd.com/read/29792025/hierarchical-nanostructures-of-nitrogen-doped-porous-carbon-polyhedrons-confined-in-carbon-nanosheets-for-high-performance-supercapacitors
#12
Zhe Zhao, Siliang Liu, Jixin Zhu, Jingsan Xu, Le Li, Zhaoqi Huang, Chao Zhang, Tianxi Liu
Interconnected close-packed nitrogen-doped porous carbon polyhedrons (NCPs) confined in a two-dimensional carbon nanosheets (CNSs) have been prepared through a sustainable one-pot pyrolysis of a simple solid mixture of zeolitic imidazolate framework-8 (ZIF-8) crystals and organic potassium as the precursors. The hierarchically organized framework of the NCP-CNS composites enables NCPs and CNSs acting as well-defined electrolyte reservoirs and mechanical buffers accommodating large volume expansions of NCPs, respectively...
May 24, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29791856/activation-of-the-arterial-program-drives-development-of-definitive-hemogenic-endothelium-with-lymphoid-potential
#13
Mi Ae Park, Akhilesh Kumar, Ho Sun Jung, Gene Uenishi, Oleg V Moskvin, James A Thomson, Igor I Slukvin
Understanding the pathways guiding the development of definitive hematopoiesis with lymphoid potential is essential for advancing human pluripotent stem cell (hPSC) technologies for the treatment of blood diseases and immunotherapies. In the embryo, lymphoid progenitors and hematopoietic stem cells (HSCs) arise from hemogenic endothelium (HE) lining arteries but not veins. Here, we show that activation of the arterial program through ETS1 overexpression or by modulating MAPK/ERK signaling pathways at the mesodermal stage of development dramatically enhanced the formation of arterial-type HE expressing DLL4 and CXCR4...
May 22, 2018: Cell Reports
https://www.readbyqxmd.com/read/29791846/myosin-iia-promotes-antibody-responses-by-regulating-b-cell-activation-acquisition-of-antigen-and-proliferation
#14
Robbert Hoogeboom, Elizabeth M Natkanski, Carla R Nowosad, Dessislava Malinova, Rajesh P Menon, Antonio Casal, Pavel Tolar
B cell responses are regulated by antigen acquisition, processing, and presentation to helper T cells. These functions are thought to depend on contractile activity of non-muscle myosin IIa. Here, we show that B cell-specific deletion of the myosin IIa heavy chain reduced the numbers of bone marrow B cell precursors and splenic marginal zone, peritoneal B1b, and germinal center B cells. In addition, myosin IIa-deficient follicular B cells acquired an activated phenotype and were less efficient in chemokinesis and extraction of membrane-presented antigens...
May 22, 2018: Cell Reports
https://www.readbyqxmd.com/read/29791801/magnetically-controlled-liposome-aggregates-for-on-demand-release-of-reactive-payloads
#15
Jan Haša, Jaroslav Hanuš, Frantisek Stepanek
A colloidal system able to act as a miniature reactor for on-demand release of reactive payloads has been demonstrated. The system is based on sub-micrometers aggregates consisting of anionic liposomes that act as storage reservoirs for the reactants, superparamagnetic iron oxide nanoparticles (SPION) that enable magnetic positioning in space and controlled release of reactants from the liposomes by radiofrequency stimulation, and an oppositely charged polyelectrolyte (poly-L-lysine) that keeps the constituent elements within the aggregates at a defined ratio...
May 23, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29791673/development-of-a-clinical-protocol-for-detection-of-cervical-cancer-precursor-lesions
#16
Deise Maria Do Nascimento Sousa, Ana Carolina Maria Araújo Chagas, Camila Teixeira Moreira Vasconcelos, Airton Tetelbom Stein, Mônica Oliveira Batista Oriá
OBJECTIVE: to develop and validate the content of a clinical protocol aimed at prevention of cervical cancer in primary care. METHOD: technological research according to the steps: (1) submission of the project to the research ethics committee; (2) bibliographic survey; (3) elaboration of the clinical protocol; and (4) content validation. In the third step, the information was collected through bibliographic research and gynecology specialists were consulted. For the final step, four judges were selected to evaluate the clinical protocol according to AGREE 2...
2018: Revista Latino-americana de Enfermagem
https://www.readbyqxmd.com/read/29791179/-virilization-as-demonstration-of-hypertestosteronism-by-ovarian-tumor-case-report
#17
Michal Mokáň, František Nehaj, Juraj Sokol, Peter Vaňuga, Marián Mokáň
Hypertestosteronism as part of hyperandrogenic states in women is generally defined as abundance of male hormones (in this case abundance of testosterone). Spectrum of clinical symptoms include menstrual disorders, amenorrhoea, different range of hirsutism and virilization. Statistically, most androgen secreting tumors are ovarian aetiology (testosterone secreting tumors located in suprarenal gland are very rare). This rare tumor may produce excess amounts of testosterone, as well as its precursor androstenedione...
2018: Vnitr̆ní Lékar̆ství
https://www.readbyqxmd.com/read/29791145/slow-starter-enzymes-role-of-active-site-architecture-in-the-catalytic-control-in-the-biosynthesis-of-taxadiene-by-taxadiene-synthase
#18
Tamar Ansbacher, Yehoshua Freud, Dan Thomas Major
Taxadiene synthase (TXS) catalyzes the formation of the natural product Taxa-4(5),11(12)-diene (henceforth Taxadiene). Taxadiene is the precursor in the formation of Taxol, which is an important natural anti-cancer agent. In the current study, we present a detailed mechanistic view of the biosynthesis of Taxadiene by TXS, using a hybrid quantum mechanics-molecular mechanics potential in conjunction with free energy simulation methods. The obtained free energy landscape displays initial endergonic steps followed by a step-wise downhill profile, which is an emerging free energy fingerprint for type I terpene synthases...
May 23, 2018: Biochemistry
https://www.readbyqxmd.com/read/29791082/higher-acenes-by-on-surface-dehydrogenation-from-heptacene-to-undecacene
#19
Antonio M Echavarren, Rafal Zuzak, Ruth Dorel, Marek Kolmer, Marek Szymonski, Szymon Godlewski
A unified approach to the synthesis of the series of higher acenes up to previously unreported undecacene has been developed through the on-surface dehydrogenation of partially saturated precursors. These molecules could be converted into the parent acenes by atomic manipulation with the tip of a scanning tunneling and atomic force microscope (STM/AFM) as well as by on-surface annealing. The structure of the generated acenes has been visualized by high resolution non-contact AFM imaging and the evolution of the transport gap with the increase of the number of fused benzene rings has been determined on the basis of scanning tunneling spectroscopy (STS) measurements...
May 23, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29790987/structural-accommodations-accompanying-splicing-of-a-group-ii-intron-rnp
#20
Xiaolong Dong, Srivathsan Ranganathan, Guosheng Qu, Carol Lyn Piazza, Marlene Belfort
Group II introns, the putative progenitors of spliceosomal introns and retrotransposons, are ribozymes that are capable of self-splicing and DNA invasion. In the cell, group II introns form ribonucleoprotein (RNP) complexes with an intron-encoded protein, which is essential to folding, splicing and retromobility of the intron. To understand the structural accommodations underlying splicing, in preparation for retromobility, we probed the endogenously expressed Lactococcus lactis Ll.LtrB group II intron RNP using SHAPE...
May 22, 2018: Nucleic Acids Research
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