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https://www.readbyqxmd.com/read/29241298/etiology-of-salinity-and-water-origin-the-main-dilemma-of-badab-sourt-a-unique-travertine-spring
#1
Rahim Bagheri, Hadi Jafari, Fatemeh Bagheri
Badab Sourt travertine-depositing springs in the north of Iran, naturally create a unique surreal landscape containing a range of stepped travertine terraces, similarly found only in a few other places on earth. This site comprises of three travertine saline springs with different values of salinity and discharge (SP1 , SP2 , and SP3 ) and one non-travertine fresh karstic spring (SP4 ) within a distance of about 300 m. The etiology behind this salinity and the water origin are the main research's dilemma that were investigated using geological, hydrochemical, and stable isotopic techniques...
December 14, 2017: Ground Water
https://www.readbyqxmd.com/read/29241136/submillimeter-scale-heterogeneity-of-labile-phosphorus-in-sediments-characterized-by-diffusive-gradients-in-thin-films-and-spatial-analysis
#2
Yuting Meng, Shiming Ding, Mengdan Gong, Musong Chen, Yan Wang, Xianfang Fan, Lei Shi, Chaosheng Zhang
Sediments have a heterogeneous distribution of labile redox-sensitive elements due to a drastic downward transition from oxic to anoxic condition as a result of organic matter degradation. Characterization of the heterogeneous nature of sediments is vital for understanding of small-scale biogeochemical processes. However, there are limited reports on the related specialized methodology. In this study, the monthly distributions of labile phosphorus (P), a redox-sensitive limiting nutrient, were measured in the eutrophic Lake Taihu by Zr-oxide diffusive gradients in thin films (Zr-oxide DGT) on a two-dimensional (2D) submillimeter level...
December 5, 2017: Chemosphere
https://www.readbyqxmd.com/read/29241059/moxidectin-residues-in-lamb-tissues-development-and-validation-of-analytical-method-by-uhplc-ms-ms
#3
Michelle Del Bianchi A Cruz, Maria A M Fernandes, Patricia A de C Braga, Alda L G Monteiro, Daniela Daniel, Felix G R Reyes
The development and validation of a throughput method for the quantitation of moxidectin residues in lamb target tissues (muscle, kidney, liver and fat) was conducted using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). To achieve higher recovery of the analyte from the matrices, a modified QuEChERS method was used for sample preparation. The chromatographic separation was achieved using a Zorbax Eclipse Plus C18 RRHD column with a mobile phase comprising 5mM ammonium formate solution +0...
December 11, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/29240996/transfer-mechanism-uptake-kinetic-process-and-bioavailability-of-p-cu-cd-pb-and-zn-in-macrophyte-rhizosphere-using-dgt
#4
Shengrui Wang, Zhihao Wu, Jun Luo
The transfer-uptake-bioavailability of phosphorus (P), Cu, Cd, Zn and Pb in rhizosphere of Zizania latifolia (ZL) and Myriophyllum verticiilaturn (MV) cultivated in rhizoboxes in Lake Erhai (China) is investigated by DGT (diffusive gradients in thin films) technique. DGT induced fluxes in sediments (DIFS) model reveals that resupply ability (r), liable pool size in sediment solid (kd), kinetic parameter (k-1) or response time (Tc) control the diffusion-resupply characters of P and Cu (standing for four metals) in rhizosphere interface...
December 14, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/29240786/time-trend-analysis-2009-2016-of-antimicrobial-susceptibility-in-neisseria-gonorrhoeae-isolated-in-italy-following-the-introduction-of-the-combined-antimicrobial-therapy
#5
Paola Stefanelli, Maria Fenicia Vescio, Maria Paola Landini, Ivano Dal Conte, Alberto Matteelli, Antonio Cristaudo, Marina Gaino, Marco Cusini, Anna Maria Barbui, Antonella Mencacci, Rosella De Nittis, Valeria Ghisetti, Elena Stroppiana, Anna Carannante
INTRODUCTION: Neisseria gonorrhoeae (NG) antimicrobial susceptibility trends to azithromycin, cefixime and ceftriaxone were analyzed, from 2009 to 2016, to monitor changing antimicrobial susceptibility concomitant with the change in prescribing practice in 2012 from cefixime, or ceftriaxone, to ceftriaxone plus azithromycin. Patient characteristics predictive to be infected by antibiotic resistant N. gonorrhoeae were estimated. Finally, the protocol for the treatment of gonorrhoea, in comparison with the international guidelines, was also evaluated...
2017: PloS One
https://www.readbyqxmd.com/read/29240151/wavefront-sensing-with-a-thin-diffuser
#6
Pascal Berto, Hervé Rigneault, Marc Guillon
We propose and implement a broadband, compact, and low-cost wavefront sensing scheme by simply placing a thin diffuser in the close vicinity of a camera. The local wavefront gradient is determined from the local translation of the speckle pattern. The translation vector map is computed thanks to a fast diffeomorphic image registration algorithm and integrated to reconstruct the wavefront profile. The simple translation of speckle grains under local wavefront tip/tilt is ensured by the so-called "memory effect" of the diffuser...
December 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/29239354/an-electric-eel-inspired-soft-power-source-from-stacked-hydrogels
#7
Thomas B H Schroeder, Anirvan Guha, Aaron Lamoureux, Gloria VanRenterghem, David Sept, Max Shtein, Jerry Yang, Michael Mayer
Progress towards the integration of technology into living organisms requires electrical power sources that are biocompatible, mechanically flexible, and able to harness the chemical energy available inside biological systems. Conventional batteries were not designed with these criteria in mind. The electric organ of the knifefish Electrophorus electricus (commonly known as the electric eel) is, however, an example of an electrical power source that operates within biological constraints while featuring power characteristics that include peak potential differences of 600 volts and currents of 1 ampere...
December 13, 2017: Nature
https://www.readbyqxmd.com/read/29239094/controlling-the-polymer-microstructure-in-anionic-polymerization-by-compartmentalization
#8
Elisabeth Rieger, Jan Blankenburg, Eduard Grune, Manfred Wagner, Katharin Landfester, Frederik Roman Wurm
An ideal random anionic copolymerization is forced to gradient structures by physical separation of two monomers in emulsion compartments. One monomer (M) is preferably soluble in the droplets, while the other one (D) prefers the continuous phase of a DMSO-in-cyclohexane emulsion. The living anionic copolymerization of two activated aziridines is thus confined to the DMSO compartments as polymerization occurs selectively in the droplets. Dilution of the continuous phase adjusts the local concentration of monomer D in the droplets and thus the gradient of the resulting copolymer...
December 13, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/29239049/a-new-3d-printing-strategy-by-harnessing-deformation-instability-and-fracture-of-viscoelastic-inks
#9
Hyunwoo Yuk, Xuanhe Zhao
Direct ink writing (DIW) has demonstrated great potential as a multimaterial multifunctional fabrication method in areas as diverse as electronics, structural materials, tissue engineering, and soft robotics. During DIW, viscoelastic inks are extruded out of a 3D printer's nozzle as printed fibers, which are deposited into patterns when the nozzle moves. Hence, the resolution of printed fibers is commonly limited by the nozzle's diameter, and the printed pattern is limited by the motion paths. These limits have severely hampered innovations and applications of DIW 3D printing...
December 14, 2017: Advanced Materials
https://www.readbyqxmd.com/read/29238751/tree-leaf-bacterial-community-structure-and-diversity-differ-along-a-gradient-of-urban-intensity
#10
Isabelle Laforest-Lapointe, Christian Messier, Steven W Kembel
Tree leaf-associated microbiota have been studied in natural ecosystems but less so in urban settings, where anthropogenic pressures on trees could impact microbial communities and modify their interaction with their hosts. Additionally, trees act as vectors spreading bacterial cells in the air in urban environments due to the density of microbial cells on aerial plant surfaces. Characterizing tree leaf bacterial communities along an urban gradient is thus key to understand the impact of anthropogenic pressures on urban tree-bacterium interactions and on the overall urban microbiome...
November 2017: MSystems
https://www.readbyqxmd.com/read/29238550/plant-community-composition-and-species-richness-in-the-high-arctic-tundra-from-the-present-to-the-future
#11
Jacob Nabe-Nielsen, Signe Normand, Francis K C Hui, Lærke Stewart, Christian Bay, Louise I Nabe-Nielsen, Niels Martin Schmidt
Arctic plant communities are altered by climate changes. The magnitude of these alterations depends on whether species distributions are determined by macroclimatic conditions, by factors related to local topography, or by biotic interactions. Our current understanding of the relative importance of these conditions is limited due to the scarcity of studies, especially in the High Arctic. We investigated variations in vascular plant community composition and species richness based on 288 plots distributed on three sites along a coast-inland gradient in Northeast Greenland using a stratified random design...
December 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/29238529/elevational-diversity-gradients-of-tibetan-loaches-the-relative-roles-of-ecological-and-evolutionary-processes
#12
Chenguang Feng, Yongjie Wu, Fei Tian, Chao Tong, Yongtao Tang, Renyi Zhang, Guogang Li, Kai Zhao
It is widely believed that species richness patterns (SRPs) are shaped by both ecological and evolutionary processes. However, the relative roles of these processes remain unclear, especially for aquatic organisms. In this study, we integrated ecological and evolutionary measures to tease apart the relative influences of these factors on the SRP of Tibetan loaches along an extensive elevational gradient. We found that the Tibetan loaches displayed a richness pattern that peaked at midelevations. The mean annual temperature (MAT), mid-domain effect (MDE), and summed age of colonization (SAC, complex of colonization age and colonization frequency) were the main drivers, accounting for 85%, 51%, and 88% of the variations in the SRP, respectively...
December 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/29238527/ancestrality-and-evolution-of-trait-syndromes-in-finches-fringillidae
#13
Jean-François Ponge, Dario Zuccon, Marianne Elias, Sandrine Pavoine, Pierre-Yves Henry, Marc Théry, Éric Guilbert
Species traits have been hypothesized by one of us (Ponge, 2013) to evolve in a correlated manner as species colonize stable, undisturbed habitats, shifting from "ancestral" to "derived" strategies. We predicted that generalism, r-selection, sexual monomorphism, and migration/gregariousness are the ancestral states (collectively called strategy A) and evolved correlatively toward specialism, K-selection, sexual dimorphism, and residence/territoriality as habitat stabilized (collectively called B strategy). We analyzed the correlated evolution of four syndromes, summarizing the covariation between 53 traits, respectively, involved in ecological specialization, r-K gradient, sexual selection, and dispersal/social behaviors in 81 species representative of Fringillidae, a bird family with available natural history information and that shows variability for all these traits...
December 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/29238525/have-bird-distributions-shifted-along-an-elevational-gradient-on-a-tropical-mountain
#14
Marconi Campos-Cerqueira, Wayne J Arendt, Joseph M Wunderle, T Mitchell Aide
An upward shift in elevation is one of the most conspicuous species responses to climate change. Nevertheless, downward shifts and, apparently, the absences of response have also been recently reported. Given the growing evidence of multiple responses of species distributions due to climate change and the paucity of studies in the tropics, we evaluated the response of a montane bird community to climate change, without the confounding effects of land-use change. To test for elevational shifts, we compared the distribution of 21 avian species in 1998 and 2015 using occupancy models...
December 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/29237810/behavioural-tuning-in-a-tropical-amphibian-along-an-altitudinal-gradient
#15
Sebastiaan W F Meenderink, Patricia M Quiñones, Peter M Narins
Males of the coqui treefrog, Eleutherodactylus coqui, produce a distinct two-note 'co-qui' advertisement call from sunset to midnight throughout most of the year. Previous work established that both the spectrotemporal aspects of the call and the frequency of highest inner-ear sensitivity change with altitude above sea level. These variations are such that the frequency of the emitted co-note closely matches the frequency to which the inner ear is most sensitive. Given this parallel variation, we expected that the call-evoked behavioural response of male coqui treefrogs would also show an altitude dependence, and hypothesized that males would produce their most robust acoustical territorial response to advertisement calls that match calls from their own altitude...
December 2017: Biology Letters
https://www.readbyqxmd.com/read/29237756/the-prokaryotic-na-ca2-exchanger-ncx_mj-transports-na-and-ca2-in-a-3-1-stoichiometry
#16
Irina Shlosman, Fabrizio Marinelli, José D Faraldo-Gómez, Joseph A Mindell
Intracellular Ca2+ signals control a wide array of cellular processes. These signals require spatial and temporal regulation of the intracellular Ca2+ concentration, which is achieved in part by a class of ubiquitous membrane proteins known as sodium-calcium exchangers (NCXs). NCXs are secondary-active antiporters that power the translocation of Ca2+ across the cell membrane by coupling it to the flux of Na+ in the opposite direction, down an electrochemical gradient. Na+ and Ca2+ are translocated in separate steps of the antiport cycle, each of which is thought to entail a mechanism whereby ion-binding sites within the protein become alternately exposed to either side of the membrane...
December 13, 2017: Journal of General Physiology
https://www.readbyqxmd.com/read/29237738/ascending-vasa-recta-are-angiopoietin-tie2-dependent-lymphatic-like-vessels
#17
Yael Kenig-Kozlovsky, Rizaldy P Scott, Tuncer Onay, Isabel Anna Carota, Benjamin R Thomson, Hyea Jin Gil, Veronica Ramirez, Shinji Yamaguchi, Christine E Tanna, Stefan Heinen, Christine Wu, Radu V Stan, Janet D Klein, Jeff M Sands, Guillermo Oliver, Susan E Quaggin
Urinary concentrating ability is central to mammalian water balance and depends on a medullary osmotic gradient generated by a countercurrent multiplication mechanism. Medullary hyperosmolarity is protected from washout by countercurrent exchange and efficient removal of interstitial fluid resorbed from the loop of Henle and collecting ducts. In most tissues, lymphatic vessels drain excess interstitial fluid back to the venous circulation. However, the renal medulla is devoid of classic lymphatics. Studies have suggested that the fenestrated ascending vasa recta (AVRs) drain the interstitial fluid in this location, but this function has not been conclusively shown...
December 13, 2017: Journal of the American Society of Nephrology: JASN
https://www.readbyqxmd.com/read/29237465/mid-term-results-of-mitral-valve-repair-using-flexible-bands-versus-complete-rings-in-patients-with-degenerative-mitral-valve-disease-a-prospective-randomized-study
#18
Alexandr V Bogachev-Prokophiev, Alexandr V Afanasyev, Sergei I Zheleznev, Vladimir M Nazarov, Ravil M Sharifulin, Alexandr M Karaskov
BACKGROUND: We aimed to compare the outcomes of mitral valve repair with flexible band (FB) versus complete semirigid ring (SR) in degenerative mitral valve disease patients. METHODS: From September 2011 to 2014, 171 patients were randomized and underwent successful mitral valve repair using a SR (n = 85) or FB (n = 86). There were no significant between-group differences at baseline. RESULTS: There were no early mortalities. The mean follow up was 24...
December 13, 2017: Journal of Cardiothoracic Surgery
https://www.readbyqxmd.com/read/29237232/3d-printed-phantoms-mimicking-cortical-bone-for-the-assessment-of-ultrashort-echo-time-magnetic-resonance-imaging
#19
Robba Rai, David Manton, Michael G Jameson, Sonal Josan, Michael B Barton, Lois C Holloway, Gary P Liney
PURPOSE: Human cortical bone has a rapid T2 * decay, and it can be visualised using ultrashort echo time (UTE) techniques in magnetic resonance imaging (MRI). These sequences operate at the limits of gradient and transmit-receive signal performance. Development of multicompartment anthropomorphic phantoms that can mimic human cortical bone can assist with quality assurance and optimisation of UTE sequences. The aims of this study were to 1) characterise the MRI signal properties of a photopolymer resin that can be 3D printed, 2) develop multi-compartment phantoms based on the resin, and 3) demonstrate the feasibility of using these phantoms to mimic human anatomy in the assessment of UTE sequences...
December 13, 2017: Medical Physics
https://www.readbyqxmd.com/read/29237015/perceval-less-invasive-aortic-replacement-register-multicentric-spanish-experience-with-the-perceval-s-bioprosthesis-in-moderate-high-risk-aortic-surgery
#20
Elisabet Berastegui García, Maria Luisa Camara Rosell, Francisco Estevez Cid, Eladio Sanchez Dominguez, Remedios Rios Barrera, Fabrizio Sbraga, Julio Garcia Puente, Elena Rosello Diez, Gregorio Pablo Cuerpo Caballero, Juan Bustamante Munguira, Guillermo Reyes Copa, Marian Tena Pajuelo, Santiago Serrano Fiz, Jose Alfonso Buendía Miñano, Ivan García Martin, Jose Cuenca Castillo, Sergio Cánovas Lopez, Angel Gonzalez Pinto, Xavier Ruyra Baliarda
OBJECTIVES: The development of new percutaneous and surgical techniques has reduced the risk associated with aortic valve replacement procedures. We present the results of a Spanish register after initiating a programme for sutureless prostheses in moderate-high-risk patients. METHODS: This prospective multicentre study was carried out from November 2013 to November 2016. Data were obtained from 448 patients in whom a Perceval S prosthesis was implanted. RESULTS: The mean age was 79...
December 8, 2017: Interactive Cardiovascular and Thoracic Surgery
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