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https://www.readbyqxmd.com/read/28437081/silicon-induced-uv-transparency-in-phosphate-glasses-and-its-application-to-the-enhancement-of-the-uv-type-b-emission-of-gd-3
#1
José A Jiménez
The silicon route to improve the ultraviolet (UV) transparency in phosphate glasses is investigated, and further exploited to enhance the UV type B (280-320 nm) emission of gadolinium(III) relevant for biomedical applications. The glasses were synthesized with a barium-phosphate composition by melt-quenching in ambient atmosphere, and the optical properties investigated by optical absorption and photoluminescence (PL) spectroscopy including emission decay kinetics. An improvement in the UV transparency was gradually developed for the glasses melted merely with increasing amounts of Si powder...
April 24, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28435621/the-effect-of-plasma-on-shear-bond-strength-between-resin-cement-and-colored-zirconia
#2
Chan Park, Seung-Hwan Yoo, Sang-Won Park, Kwi-Dug Yun, Min-Kyung Ji, Jin-Ho Shin, Hyun-Pil Lim
PURPOSE: To investigate the effect of non-thermal atmospheric pressure plasma (NTAPP) treatment on shear bond strength (SBS) between resin cement and colored zirconia made with metal chlorides. MATERIALS AND METHODS: 60 zirconia specimens were divided into 3 groups using coloring liquid. Each group was divided again into 2 sub-groups using plasma treatment; the experimental group was treated with plasma, and the control group was untreated. The sub-groups were: N (non-colored), C (0...
April 2017: Journal of Advanced Prosthodontics
https://www.readbyqxmd.com/read/28433157/enhanced-mechanical-properties-of-chitosan-nanodiamond-composites-by-improving-interphase-using-thermal-oxidation-of-nanodiamond
#3
Zahra Delavar, Akbar Shojaei
Polymer composite films based on chitosan (CS) and nanodimaond (ND) were prepared using solution casting method. ND with variable contents of carboxylic functional group was prepared using thermal oxidation at temperature of 420°C under air atmosphere at various durations of 1.5 and 4.5h. The interfacial interaction between NDs and CS and morphological evolution of CS in presence of NDs were investigated by Fourier transform infrared (FTIR), differential scanning calorimeter (DSC) and X-ray diffraction (XRD) analyses...
July 1, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28429398/efficacy-of-passive-sampler-collection-for-atmospheric-no2-isotopes-under-simulated-environmental-conditions
#4
Justin G Coughlin, Zhongjie Yu, Emily M Elliott
RATIONALE: Nitrogen oxides or NOx (NOx  = NO + NO2 ) play an important role in air quality, atmospheric chemistry, and climate. The isotopic compositions of anthropogenic and natural NO2 sources are wide-ranging, and they can be used to constrain sources of ambient NO2 and associated atmospheric deposition of nitrogen compounds. While passive sample collection of NO2 isotopes has been used in field studies to determine NOx source influences on atmospheric deposition, this approach has not been evaluated for accuracy or precision under different environmental conditions...
April 20, 2017: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/28429066/atmospheric-pressure-maldi-for-the-noninvasive-characterization-of-carbonaceous-ink-from-renaissance-documents
#5
Giuseppe Grasso, Marzia Calcagno, Alessandro Rapisarda, Roberta D'Agata, Giuseppe Spoto
The analytical methods that are usually applied to determine the compositions of inks from ancient manuscripts usually focus on inorganic components, as in the case of iron gall ink. In this work, we describe the use of atmospheric pressure/matrix-assisted laser desorption ionization-mass spectrometry (AP/MALDI-MS) as a spatially resolved analytical technique for the study of the organic carbonaceous components of inks used in handwritten parts of ancient books for the first time. Large polycyclic aromatic hydrocarbons (L-PAH) were identified in situ in the ink of XVII century handwritten documents...
April 21, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28427738/assessment-of-a-combined-dry-anaerobic-digestion-and-post-composting-treatment-facility-for-source-separated-organic-household-waste-using-material-and-substance-flow-analysis-and-life-cycle-inventory
#6
Morten Bang Jensen, Jacob Møller, Charlotte Scheutz
The fate of total solids, volatile solids, total organic carbon, fossil carbon, biogenic carbon and 17 substances (As, Ca, CaCO3, Cd, Cl, Cr, Cu, H, Hg, K, Mg, N, Ni, O, P, Pb, S, Zn) in a combined dry anaerobic digestion and post-composting facility were assessed. Mass balances showed good results with low uncertainties for non-volatile substances, while balances for nitrogen, carbon, volatile solids and total organic carbon showed larger but reasonable uncertainties, due to volatilisation and emissions into the air...
April 17, 2017: Waste Management
https://www.readbyqxmd.com/read/28427624/ultrasound-assisted-biodiesel-production-by-a-novel-composite-of-fe-iii-based-mof-and-phosphotangestic-acid-as-efficient-and-reusable-catalyst
#7
Ahmad Nikseresht, Asra Daniyali, Mahdi Ali-Mohammadi, Ahmad Afzalinia, Abbas Mirzaie
In this work, esterification of oleic acid by various alcohols is achieved with high yields under ultrasonic irradiation. This reaction performed with a novel heterogeneous catalyst that fabricated by heteropoly acid and Fe(III)-based MOF, namely MIL-53 (Fe). Syntheses of MIL-53 and encapsulation process carry out by ultrasound irradiation at ambient temperature and atmospheric pressure. The prepared composite was characterized by various techniques such as XRD, FT-IR, SEM, BET and ICP that demonstrate excellent catalytic activities, while being highly convenient to synthesize...
July 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28426222/structural-and-dynamical-properties-of-tetra-alkyl-ammonium-bromide-aqueous-solutions-a-molecular-dynamics-simulation-study-using-a-polarizable-force-field
#8
Dengpan Dong, Justin B Hooper, Dmitry Bedrov
Understanding the behavior of aqueous solutions containing tetra-alkyl ammonium (TAA) cations is of great significance in a number of applications, including polymer membranes for fuel cells. In this work, a polarizable force field has been used to preform atomistic molecular dynamics (MD) simulations of aqueous solutions containing tetra-methyl ammonium (TMA) or tetra-butyl ammonium (TBA) cations and Br counterions. Extensive MD simulations of TMA-Br/water and TBA-Br/water systems were conducted as a function of solution composition (ion pair : water molar ratios of 1:10, 1:20, 1:30, 1:63, 1:500) at atmospheric pressure and 298K...
April 20, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28426003/a-temperate-rocky-super-earth-transiting-a-nearby-cool-star
#9
Jason A Dittmann, Jonathan M Irwin, David Charbonneau, Xavier Bonfils, Nicola Astudillo-Defru, Raphaëlle D Haywood, Zachory K Berta-Thompson, Elisabeth R Newton, Joseph E Rodriguez, Jennifer G Winters, Thiam-Guan Tan, Jose-Manuel Almenara, François Bouchy, Xavier Delfosse, Thierry Forveille, Christophe Lovis, Felipe Murgas, Francesco Pepe, Nuno C Santos, Stephane Udry, Anaël Wünsche, Gilbert A Esquerdo, David W Latham, Courtney D Dressing
M dwarf stars, which have masses less than 60 per cent that of the Sun, make up 75 per cent of the population of the stars in the Galaxy. The atmospheres of orbiting Earth-sized planets are observationally accessible via transmission spectroscopy when the planets pass in front of these stars. Statistical results suggest that the nearest transiting Earth-sized planet in the liquid-water, habitable zone of an M dwarf star is probably around 10.5 parsecs away. A temperate planet has been discovered orbiting Proxima Centauri, the closest M dwarf, but it probably does not transit and its true mass is unknown...
April 19, 2017: Nature
https://www.readbyqxmd.com/read/28422534/in-situ-sampling-of-relative-dust-devil-particle-loads-and-their-vertical-grain-size-distributions
#10
Jan Raack, Dennis Reiss, Matthew R Balme, Kamal Taj-Eddine, Gian Gabriele Ori
During a field campaign in the Sahara Desert in southern Morocco, spring 2012, we sampled the vertical grain size distribution of two active dust devils that exhibited different dimensions and intensities. With these in situ samples of grains in the vortices, it was possible to derive detailed vertical grain size distributions and measurements of the lifted relative particle load. Measurements of the two dust devils show that the majority of all lifted particles were only lifted within the first meter (∼46...
April 19, 2017: Astrobiology
https://www.readbyqxmd.com/read/28422480/chemical-characterization-of-gas-and-particle-phase-products-from-the-ozonolysis-of-%C3%AE-pinene-in-the-presence-of-dimethylamine
#11
Geoffroy Duporté, Matthieu Riva, Jevgeni Parshintsev, Enna Heikkinen, Luis M F Barreira, Nanna Myllys, Liine Heikkinen, Kari Mikael Hartonen, Markku Kulmala, Mikael Ehn, Marja-Liisa Riekkola
Amines are recognized as key compounds in new particle formation (NPF) and secondary organic aerosol (SOA) formation. In addition, ozonolysis of α-pinene contributes substantially to the formation of biogenic SOAs in the atmosphere. In the present study, ozonolysis of α-pinene in presence of dimethylamine (DMA) was investigated in a flow tube reactor. Effects of amines on SOA formation and chemical composition were examined. Enhancement of NPF and SOA formation was observed in presence of DMA. Chemical characterization of gas- and particle-phase products by high-resolution mass spectrometric techniques revealed the formation of nitrogen containing compounds...
April 19, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28418706/radiation-driven-formation-of-reactive-oxygen-species-in-oxychlorine-containing-mars-surface-analogues
#12
Christos D Georgiou, Dimitrios Zisimopoulos, Electra Kalaitzopoulou, Richard C Quinn
The present study demonstrates that γ-radiolyzed perchlorate-containing Mars soil salt analogues (in a CO2 atmosphere) generate upon H2O wetting the reactive oxygen species (ROS) superoxide radical (O2(•-)), hydrogen peroxide (H2O2), and hydroxyl radicals ((•)OH). This study also validates that analogue radiolysis forms oxychlorine species that, in turn, can UV-photolyze to (•)OH upon UV photolysis. This investigation was made possible by the development of a new assay for inorganic-origin O2(•-) and H2O2 determination and by the modification of a previous assay for soil (•)OH...
April 2017: Astrobiology
https://www.readbyqxmd.com/read/28418704/false-negatives-for-remote-life-detection-on-ocean-bearing-planets-lessons-from-the-early-earth
#13
Christopher T Reinhard, Stephanie L Olson, Edward W Schwieterman, Timothy W Lyons
Ocean-atmosphere chemistry on Earth has undergone dramatic evolutionary changes throughout its long history, with potentially significant ramifications for the emergence and long-term stability of atmospheric biosignatures. Though a great deal of work has centered on refining our understanding of false positives for remote life detection, much less attention has been paid to the possibility of false negatives, that is, cryptic biospheres that are widespread and active on a planet's surface but are ultimately undetectable or difficult to detect in the composition of a planet's atmosphere...
April 2017: Astrobiology
https://www.readbyqxmd.com/read/28416728/global-water-cycle-and-the-coevolution-of-the-earth-s-interior-and-surface-environment
#14
Jun Korenaga, Noah J Planavsky, David A D Evans
The bulk Earth composition contains probably less than 0.3% of water, but this trace amount of water can affect the long-term evolution of the Earth in a number of different ways. The foremost issue is the occurrence of plate tectonics, which governs almost all aspects of the Earth system, and the presence of water could either promote or hinder the operation of plate tectonics, depending on where water resides. The global water cycle, which circulates surface water into the deep mantle and back to the surface again, could thus have played a critical role in the Earth's history...
May 28, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/28415861/atmospheric-aerosols-clouds-chemistry-and-climate
#15
V Faye McNeill
Although too small to be seen with the human eye, atmospheric particulate matter has major impacts on the world around us, from our health to global climate. Understanding the sources, properties, and transformations of these particles in the atmosphere is among the major challenges in air quality and climate research today. Significant progress has been made over the past two decades in understanding atmospheric aerosol chemistry and its connections to climate. Advances in technology for characterizing aerosol chemical composition and physical properties have enabled rapid discovery in this area...
April 17, 2017: Annual Review of Chemical and Biomolecular Engineering
https://www.readbyqxmd.com/read/28409445/ion-mobility-spectrometry-high-resolution-ltq-orbitrap-mass-spectrometry-for-analysis-of-homemade-explosives
#16
Nathan Hagan, Ilana Goldberg, Adam Graichen, Amanda St Jean, Ching Wu, David Lawrence, Plamen Demirev
The detailed chemical characterization of homemade explosives (HMEs) and other chemicals that can mimic or mask the presence of explosives is important for understanding and improving the performance of commercial instrumentation used for explosive detection. To that end, an atmospheric-pressure drift tube ion mobility spectrometry (IMS) instrument has been successfully coupled to a commercial tandem mass spectrometry (MS) system. The tandem MS system is comprised of a linear ion trap and a high resolution Orbitrap analyzer...
April 13, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28408771/was-venus-the-first-habitable-world-of-our-solar-system
#17
M J Way, Anthony D Del Genio, Nancy Y Kiang, Linda E Sohl, David H Grinspoon, Igor Aleinov, Maxwell Kelley, Thomas Clune
Present-day Venus is an inhospitable place with surface temperatures approaching 750K and an atmosphere 90 times as thick as Earth's. Billions of years ago the picture may have been very different. We have created a suite of 3-D climate simulations using topographic data from the Magellan mission, solar spectral irradiance estimates for 2.9 and 0.715 Gya, present-day Venus orbital parameters, an ocean volume consistent with current theory, and an atmospheric composition estimated for early Venus. Using these parameters we find that such a world could have had moderate temperatures if Venus had a rotation period slower than ~16 Earth days, despite an incident solar flux 46-70% higher than Earth receives...
August 28, 2016: Geophysical Research Letters
https://www.readbyqxmd.com/read/28405217/bioprocessing-of-tea-oil-fruit-hull-with-acetic-acid-organosolv-pretreatment-in-combination-with-alkaline-h2o2
#18
Song Tang, Rukuan Liu, Fubao Fuelbiol Sun, Chunying Dong, Rui Wang, Zhongyuan Gao, Zhanying Zhang, Zhihong Xiao, Changzhu Li, Hui Li
BACKGROUND: As a natural renewable biomass, the tea oil fruit hull (TOFH) mainly consists of lignocellulose, together with some bioactive substances. Our earlier work constructed a two-stage solvent-based process, including one aqueous ethanol organosolv extraction and an atmospheric glycerol organosolv (AGO) pretreatment, for bioprocessing of the TOFH into diverse bioproducts. However, the AGO pretreatment is not as selective as expected in removing the lignin from TOFH, resulting in the limited delignification and simultaneously high cellulose loss...
2017: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/28403896/gas-fermentation-cellular-engineering-possibilities-and-scale-up
#19
REVIEW
Björn D Heijstra, Ching Leang, Alex Juminaga
Low carbon fuels and chemicals can be sourced from renewable materials such as biomass or from industrial and municipal waste streams. Gasification of these materials allows all of the carbon to become available for product generation, a clear advantage over partial biomass conversion into fermentable sugars. Gasification results into a synthesis stream (syngas) containing carbon monoxide (CO), carbon dioxide (CO2), hydrogen (H2) and nitrogen (N2). Autotrophy-the ability to fix carbon such as CO2 is present in all domains of life but photosynthesis alone is not keeping up with anthropogenic CO2 output...
April 12, 2017: Microbial Cell Factories
https://www.readbyqxmd.com/read/28401603/few-layer-black-phosphorus-carbide-field-effect-transistor-via-carbon-doping
#20
Wee Chong Tan, Yongqing Cai, Rui Jie Ng, Li Huang, Xuewei Feng, Gang Zhang, Yong-Wei Zhang, Christian A Nijhuis, Xinke Liu, Kah-Wee Ang
Black phosphorus carbide (b-PC) is a new family of layered semiconducting material that has recently been predicted to have the lightest electrons and holes among all known 2D semiconductors, yielding a p-type mobility (≈10(5) cm(2) V(-1) s(-1) ) at room temperature that is approximately five times larger than the maximum value in black phosphorus. Here, a high-performance composite few-layer b-PC field-effect transistor fabricated via a novel carbon doping technique which achieved a high hole mobility of 1995 cm(2) V(-1) s(-1) at room temperature is reported...
April 12, 2017: Advanced Materials
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