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Journal articles on the topic 'S-SNOM'

Author: Grafiati
Published: 4 June 2021
Last updated: 15 February 2022

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1

Freitas, Raul O., Adrian Cernescu, Anders Engdahl, Agnes Paulus, João E. Levandoski, Isak Martinsson, Elke Hebisch, et al. "Nano-Infrared Imaging of Primary Neurons." Cells 10, no. 10 (September 27, 2021): 2559. http://dx.doi.org/10.3390/cells10102559.

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Alzheimer’s disease (AD) accounts for about 70% of neurodegenerative diseases and is a cause of cognitive decline and death for one-third of seniors. AD is currently underdiagnosed, and it cannot be effectively prevented. Aggregation of amyloid-β (Aβ) proteins has been linked to the development of AD, and it has been established that, under pathological conditions, Aβ proteins undergo structural changes to form β-sheet structures that are considered neurotoxic. Numerous intensive in vitro studies have provided detailed information about amyloid polymorphs; however, little is known on how amyloid β-sheet-enriched aggregates can cause neurotoxicity in relevant settings. We used scattering-type scanning near-field optical microscopy (s-SNOM) to study amyloid structures at the nanoscale, in individual neurons. Specifically, we show that in well-validated systems, s-SNOM can detect amyloid β-sheet structures with nanometer spatial resolution in individual neurons. This is a proof-of-concept study to demonstrate that s-SNOM can be used to detect Aβ-sheet structures on cell surfaces at the nanoscale. Furthermore, this study is intended to raise neurobiologists’ awareness of the potential of s-SNOM as a tool for analyzing amyloid β-sheet structures at the nanoscale in neurons without the need for immunolabeling.
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2

Hegenbarth, R., A. Steinmann, S. Mastel, S. Amarie, A. J. Huber, R. Hillenbrand, S. Y. Sarkisov, and H. Giessen. "High-power femtosecond mid-IR sources for s-SNOM applications." Journal of Optics 16, no. 9 (September 1, 2014): 094003. http://dx.doi.org/10.1088/2040-8978/16/9/094003.

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3

Yao, Ziheng, Suheng Xu, Debo Hu, Xinzhong Chen, Qing Dai, and Mengkun Liu. "Nanoimaging and Nanospectroscopy of Polaritons with Time Resolved s ‐SNOM." Advanced Optical Materials 8, no. 5 (September 9, 2019): 1901042. http://dx.doi.org/10.1002/adom.201901042.

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4

Németh, Gergely, Dániel Datz, Áron Pekker, Takeshi Saito, Oleg Domanov, Hidetsugu Shiozawa, Sándor Lenk, Béla Pécz, Pál Koppa, and Katalin Kamarás. "Near-field infrared microscopy of nanometer-sized nickel clusters inside single-walled carbon nanotubes." RSC Advances 9, no. 59 (2019): 34120–24. http://dx.doi.org/10.1039/c9ra07089c.

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5

Zhu, Qianqian, Rui Zhou, Jun Liu, Jianzhong Sun, and Qianqian Wang. "Recent Progress on the Characterization of Cellulose Nanomaterials by Nanoscale Infrared Spectroscopy." Nanomaterials 11, no. 5 (May 20, 2021): 1353. http://dx.doi.org/10.3390/nano11051353.

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Researches of cellulose nanomaterials have seen nearly exponential growth over the past several decades for versatile applications. The characterization of nanostructural arrangement and local chemical distribution is critical to understand their role when developing cellulose materials. However, with the development of current characterization methods, the simultaneous morphological and chemical characterization of cellulose materials at nanoscale resolution is still challenging. Two fundamentally different nanoscale infrared spectroscopic techniques, namely atomic force microscope based infrared spectroscopy (AFM-IR) and infrared scattering scanning near field optical microscopy (IR s-SNOM), have been established by the integration of AFM with IR spectroscopy to realize nanoscale spatially resolved imaging for both morphological and chemical information. This review aims to summarize and highlight the recent developments in the applications of current state-of-the-art nanoscale IR spectroscopy and imaging to cellulose materials. It briefly outlines the basic principles of AFM-IR and IR s-SNOM, as well as their advantages and limitations to characterize cellulose materials. The uses of AFM-IR and IR s-SNOM for the understanding and development of cellulose materials, including cellulose nanomaterials, cellulose nanocomposites, and plant cell walls, are extensively summarized and discussed. The prospects of future developments in cellulose materials characterization are provided in the final part.
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6

Wiecha, Matthias M., Rohit Kapoor, Alexander V. Chernyadiev, Kęstutis Ikamas, Alvydas Lisauskas, and Hartmut G. Roskos. "Antenna-coupled field-effect transistors as detectors for terahertz near-field microscopy." Nanoscale Advances 3, no. 6 (2021): 1717–24. http://dx.doi.org/10.1039/d0na00928h.

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We report the successful implementation of antenna-coupled terahertz field-effect transistors (TeraFETs) as homodyne detectors in a scattering-type scanning near-field optical microscope (s-SNOM) operating with radiation at 246.5 GHz.
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7

Rose, M. A., J. Barnett, D. Wendland, F. V. E. Hensling, J. M. Boergers, M. Moors, R. Dittmann, T. Taubner, and F. Gunkel. "Local inhomogeneities resolved by scanning probe techniques and their impact on local 2DEG formation in oxide heterostructures." Nanoscale Advances 3, no. 14 (2021): 4145–55. http://dx.doi.org/10.1039/d1na00190f.

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Using c-AFM and s-SNOM, we show the influence of local inhomogeneities on the LAO/STO 2DEG formation by mapping its distribution. The nanoscopic arrangement of insulating regions alters the conductive behavior down to low temperatures.
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8

Walla, Frederik, Matthias M. Wiecha, Nicolas Mecklenbeck, Sabri Beldi, Fritz Keilmann, Mark D. Thomson, and Hartmut G. Roskos. "Anisotropic excitation of surface plasmon polaritons on a metal film by a scattering-type scanning near-field microscope with a non-rotationally-symmetric probe tip." Nanophotonics 7, no. 1 (January 1, 2018): 269–76. http://dx.doi.org/10.1515/nanoph-2017-0042.

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AbstractWe investigated the excitation of surface plasmon polaritons on gold films with the metallized probe tip of a scattering-type scanning near-field optical microscope (s-SNOM). The emission of the polaritons from the tip, illuminated by near-infrared laser radiation, was found to be anisotropic and not circularly symmetric as expected on the basis of literature data. We furthermore identified an additional excitation channel via light that was reflected off the tip and excited the plasmon polaritons at the edge of the metal film. Our results, while obtained for a non-rotationally-symmetric type of probe tip and thus specific for this situation, indicate that when an s-SNOM is employed for the investigation of plasmonic structures, the unintentional excitation of surface waves and anisotropic surface wave propagation must be considered in order to correctly interpret the signatures of plasmon polariton generation and propagation.
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9

Wirth, Konstantin G., Heiko Linnenbank, Tobias Steinle, Luca Banszerus, Eike Icking, Christoph Stampfer, Harald Giessen, and Thomas Taubner. "Tunable s-SNOM for Nanoscale Infrared Optical Measurement of Electronic Properties of Bilayer Graphene." ACS Photonics 8, no. 2 (January 28, 2021): 418–23. http://dx.doi.org/10.1021/acsphotonics.0c01442.

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10

Yao, Ziheng, Suheng Xu, Debo Hu, Xinzhong Chen, Qing Dai, and Mengkun Liu. "Polariton Spectroscopy: Nanoimaging and Nanospectroscopy of Polaritons with Time Resolved s ‐SNOM (Advanced Optical Materials 5/2020)." Advanced Optical Materials 8, no. 5 (March 2020): 2070019. http://dx.doi.org/10.1002/adom.202070019.

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11

Gigler, Alexander M., Andreas J. Huber, Michael Bauer, Alexander Ziegler, Rainer Hillenbrand, and Robert W. Stark. "Nanoscale residual stress-field mapping around nanoindents in SiC by IR s-SNOM and confocal Raman microscopy." Optics Express 17, no. 25 (November 23, 2009): 22351. http://dx.doi.org/10.1364/oe.17.022351.

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12

Vrečko, Janez. "Kons IKARUS, TIGER in fašizem." Keria: Studia Latina et Graeca 12, no. 2-3 (December 31, 2010): 345. http://dx.doi.org/10.4312/keria.12.2-3.345-360.

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Kosovelov postgravitacijski kons Ikarus in drugi konsi z ikarsko tematiko in načrtovana pesniška zbirkaIkarov senso ne le časovno, prostorsko, ampak tudi politično obarvani in dokazujejo pesnikovo intenzivno vmeščenost v osrčje konstruktivističnega avantgardizma, potrjujejo pa tudi, da je Kosovel v evropskem prostoru uspešno uveljavil literarni konstruktivizem. Z ikarsko tematiko sta dva izjemna ustvarjalca, Tatlin z Letatlinom in Kosovel z »Ikarovim snom«, sanjala »sanje, stare kot človeštvo«, da bi se z njihovo pomočjo osvobodila dveh strahotnih režimov tedanjega časa, fašizma in stalinizma. Kosovelu so bili pritem uporu zgled prav homunkuli, ki so se počlovečili tako, da so se dokopali do čustev in strasti in s tem presegli načrte svojega stvaritelja, fašistične diktature, ki jih je želela brez duše in čustev, v celoti podrejene mehaničnemu suženjskemu delu.
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13

Pollard, Benjamin, and Markus B. Raschke. "Correlative infrared nanospectroscopic and nanomechanical imaging of block copolymer microdomains." Beilstein Journal of Nanotechnology 7 (April 22, 2016): 605–12. http://dx.doi.org/10.3762/bjnano.7.53.

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Intermolecular interactions and nanoscale phase separation govern the properties of many molecular soft-matter systems. Here, we combine infrared vibrational scattering scanning near-field optical microscopy (IR s-SNOM) with force–distance spectroscopy for simultaneous characterization of both nanoscale optical and nanomechanical molecular properties through hybrid imaging. The resulting multichannel images and correlative analysis of chemical composition, spectral IR line shape, modulus, adhesion, deformation, and dissipation acquired for a thin film of a nanophase separated block copolymer (PS-b-PMMA) reveal complex structural variations, in particular at domain interfaces, not resolved in any individual signal channel alone. These variations suggest that regions of multicomponent chemical composition, such as the interfacial mixing regions between microdomains, are correlated with high spatial heterogeneity in nanoscale material properties.
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14

Amrania, H., L. Drummond, R. C. Coombes, S. Shousha, L. Woodley-Barker, K. Weir, W. Hart, I. Carter, and C. C. Phillips. "New IR imaging modalities for cancer detection and for intra-cell chemical mapping with a sub-diffraction mid-IR s-SNOM." Faraday Discussions 187 (2016): 539–53. http://dx.doi.org/10.1039/c5fd00150a.

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We present two new modalities for generating chemical maps. Both are mid-IR based and aimed at the biomedical community, but they differ substantially in their technological readiness. The first, so-called “Digistain”, is a technologically mature “locked down” way of acquiring diffraction-limited chemical images of human cancer biopsy tissue. Although it is less flexible than conventional methods of acquiring IR images, this is an intentional, and key, design feature. It allows it to be used, on a routine basis, by clinical personnel themselves. It is in the process of a full clinical evaluation and the philosophy behind the approach is discussed. The second modality is a very new, probe-based “s-SNOM”, which we are developing in conjunction with a new family of tunable “Quantum Cascade Laser” (QCL) diode lasers. Although in its infancy, this instrument can already deliver ultra-detailed chemical images whose spatial resolutions beat the normal diffraction limit by a factor of ∼1000. This is easily enough to generate chemical maps of the insides of single cells for the first time, and a range of new possible scientific applications are explored.
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15

Čačić, Marija. "45. obljetnica rada Društva knjižničara Slavonije, Baranje i Srijema." Vjesnik bibliotekara Hrvatske 64, no. 1 (May 24, 2021): 319. http://dx.doi.org/10.30754/vbh.64.1.856.

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Cilj. Cilj je rada prikazati osnivanje i razvoj Društva knjižničara Slavonije, Baranje i Srijema tijekom 45 godina, ponajviše u kontekstu razvoja hrvatskoga knjižničarstva i knjižničarskih društava te njegov doprinos knjižničarskoj struci i zajednici kako na regionalnoj tako i na nacionalnoj, ali i međunarodnoj razini. Pristup/metodologija/dizajn. Istraživanju se pristupilo iščitavanjem objavljenih publikacija i dostupnih dokumenata. Na temelju podataka prikupljenih iz arhivskog gra- diva Društva knjižničara Slavonije, Baranje i Srijema, Spomenice DKSBS-a, tiska te postojećih radova članova Društva, u radu se donose informacije o osnutku, načinima djelovanja i razvoja Društva te planovima za budući razvitak. Rezultati. Rad daje detaljan uvid u povijesni razvoj Društva knjižničara Slavonije, Baranje i Srijema te ukazuje na njegovu povezanost s društvenim i kulturnim zbivanji- ma. Kao i knjižnice, i knjižničarske su se udruge tijekom svoga razvoja suočavale s broj- nim poteškoćama poput nedostatka prostora i financijske potpore, ali su uvijek nastojala pravovaljano odgovoriti izazovima vremena i potrebama zajednice. Originalnost/vrijednost. Rad predstavlja značajan doprinos povijesti knjižničar- stva na području Republike Hrvatske na primjeru jedne lokalne knjižničarske udruge promatrane kroz društveni kontekst. Korišten je arhivski materijal, što radu daje dodatnu vrijednost. Kako je prvi put dan takav pregled rada Društva, može poslužiti i kao osnova za daljnja istraživanja, ali može biti inspirativnim i za pisanje pregleda o povije- snom razvoju drugih regionalnih knjižničarskih društava.
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16

Aguilar-Merino, Patricia, Gonzalo Álvarez-Pérez, Javier Taboada-Gutiérrez, Jiahua Duan, Iván Prieto, Luis Manuel Álvarez-Prado, Alexey Y. Nikitin, Javier Martín-Sánchez, and Pablo Alonso-González. "Extracting the Infrared Permittivity of SiO2 Substrates Locally by Near-Field Imaging of Phonon Polaritons in a van der Waals Crystal." Nanomaterials 11, no. 1 (January 7, 2021): 120. http://dx.doi.org/10.3390/nano11010120.

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Layered materials in which individual atomic layers are bonded by weak van der Waals forces (vdW materials) constitute one of the most prominent platforms for materials research. Particularly, polar vdW crystals, such as hexagonal boron nitride (h-BN), alpha-molybdenum trioxide (α-MoO3) or alpha-vanadium pentoxide (α-V2O5), have received significant attention in nano-optics, since they support phonon polaritons (PhPs)―light coupled to lattice vibrations― with strong electromagnetic confinement and low optical losses. Recently, correlative far- and near-field studies of α-MoO3 have been demonstrated as an effective strategy to accurately extract the permittivity of this material. Here, we use this accurately characterized and low-loss polaritonic material to sense its local dielectric environment, namely silica (SiO2), one of the most widespread substrates in nanotechnology. By studying the propagation of PhPs on α-MoO3 flakes with different thicknesses laying on SiO2 substrates via near-field microscopy (s-SNOM), we extract locally the infrared permittivity of SiO2. Our work reveals PhPs nanoimaging as a versatile method for the quantitative characterization of the local optical properties of dielectric substrates, crucial for understanding and predicting the response of nanomaterials and for the future scalability of integrated nanophotonic devices.
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17

Ungureanu, Simona, Branko Kolaric, Jianing Chen, Rainer Hillenbrand, and Renaud A. L. Vallée. "Far-field disentanglement of modes in hybrid plasmonic-photonic crystals by fluorescence nano-reporters." Nanophotonics 2, no. 3 (July 1, 2013): 173–85. http://dx.doi.org/10.1515/nanoph-2013-0004.

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AbstractIn this paper, the resonance modes exhibited by a hybrid nanostructure have been disentangled in the far-field owing to narrow-band fluorescence nano-reporters. Hybrid plasmonic-photonic crystals were fabricated using large (457 nm) monodisperse polystyrene spheres self-assembled into 2D photonic crystals and subsequently coated by a 30 nm thick silver layer. Such structures exhibit a complex resonance pattern, which has been elucidated owing to numerical simulations and electric near-field patterns obtained with a scattering type scanning near-field optical microscope (s-SNOM). For the sake of disentangling the resonance modes of the hybrid structure in the far-field, different types of semiconductor quantum dots (QDs), acting as nano-reporters of the local interactions, were dispersed on top of distinct structures. Depending on the relative overlap of the emission spectrum of a particular type of QDs with the resonance features of the hybrid structure, we affect their emission rate in a unique way, as a consequence of the complex interaction occurring between the plasmo-photonic modes and the excitons. Such plasmonic structures appear to be particularly relevant for fluorescence-based sensing devices.
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18

Muller, Eric A., Thomas P. Gray, Zhou Zhou, Xinbin Cheng, Omar Khatib, Hans A. Bechtel, and Markus B. Raschke. "Vibrational exciton nanoimaging of phases and domains in porphyrin nanocrystals." Proceedings of the National Academy of Sciences 117, no. 13 (March 13, 2020): 7030–37. http://dx.doi.org/10.1073/pnas.1914172117.

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Much of the electronic transport, photophysical, or biological functions of molecular materials emerge from intermolecular interactions and associated nanoscale structure and morphology. However, competing phases, defects, and disorder give rise to confinement and many-body localization of the associated wavefunction, disturbing the performance of the material. Here, we employ vibrational excitons as a sensitive local probe of intermolecular coupling in hyperspectral infrared scattering scanning near-field optical microscopy (IR s-SNOM) with complementary small-angle X-ray scattering to map multiscale structure from molecular coupling to long-range order. In the model organic electronic material octaethyl porphyrin ruthenium(II) carbonyl (RuOEP), we observe the evolution of competing ordered and disordered phases, in nucleation, growth, and ripening of porphyrin nanocrystals. From measurement of vibrational exciton delocalization, we identify coexistence of ordered and disordered phases in RuOEP that extend down to the molecular scale. Even when reaching a high degree of macroscopic crystallinity, identify significant local disorder with correlation lengths of only a few nanometers. This minimally invasive approach of vibrational exciton nanospectroscopy and -imaging is generally applicable to provide the molecular-level insight into photoresponse and energy transport in organic photovoltaics, electronics, or proteins.
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19

Mehdi Aghaei, Sadegh, Navid Yasrebi, and Bizhan Rashidian. "Characterization of Line Nanopatterns on Positive Photoresist Produced by Scanning Near-Field Optical Microscope." Journal of Nanomaterials 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/936876.

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Line nanopatterns are produced on the positive photoresist by scanning near-field optical microscope (SNOM). A laser diode with a wavelength of 450 nm and a power of 250 mW as the light source and an aluminum coated nanoprobe with a 70 nm aperture at the tip apex have been employed. A neutral density filter has been used to control the exposure power of the photoresist. It is found that the changes induced by light in the photoresist can be detected byin situshear force microscopy (ShFM), before the development of the photoresist. Scanning electron microscope (SEM) images of the developed photoresist have been used to optimize the scanning speed and the power required for exposure, in order to minimize the final line width. It is shown that nanometric lines with a minimum width of 33 nm can be achieved with a scanning speed of 75 µm/s and a laser power of 113 mW. It is also revealed that the overexposure of the photoresist by continuous wave laser generated heat can be prevented by means of proper photoresist selection. In addition, the effects of multiple exposures of nanopatterns on their width and depth are investigated.
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20

Stomberski, Colin T., Hua-Lin Zhou, Liwen Wang, Focco van den Akker, and Jonathan S. Stamler. "Molecular recognition of S-nitrosothiol substrate by its cognate protein denitrosylase." Journal of Biological Chemistry 294, no. 5 (December 11, 2018): 1568–78. http://dx.doi.org/10.1074/jbc.ra118.004947.

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Protein S-nitrosylation mediates a large part of nitric oxide's influence on cellular function by providing a fundamental mechanism to control protein function across different species and cell types. At steady state, cellular S-nitrosylation reflects dynamic equilibria between S-nitrosothiols (SNOs) in proteins and small molecules (low-molecular-weight SNOs) whose levels are regulated by dedicated S-nitrosylases and denitrosylases. S-Nitroso-CoA (SNO-CoA) and its cognate denitrosylases, SNO-CoA reductases (SCoRs), are newly identified determinants of protein S-nitrosylation in both yeast and mammals. Because SNO-CoA is a minority species among potentially thousands of cellular SNOs, SCoRs must preferentially recognize this SNO substrate. However, little is known about the molecular mechanism by which cellular SNOs are recognized by their cognate enzymes. Using mammalian cells, molecular modeling, substrate-capture assays, and mutagenic analyses, we identified a single conserved surface Lys (Lys-127) residue as well as active-site interactions of the SNO group that mediate recognition of SNO-CoA by SCoR. Comparing SCoRK127Aversus SCoRWT HEK293 cells, we identified a SNO-CoA–dependent nitrosoproteome, including numerous metabolic protein substrates. Finally, we discovered that the SNO-CoA/SCoR system has a role in mitochondrial metabolism. Collectively, our findings provide molecular insights into the basis of specificity in SNO-CoA–mediated metabolic signaling and suggest a role for SCoR-regulated S-nitrosylation in multiple metabolic processes.
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21

Sui, Tan, Jiří Dluhoš, Tao Li, Kaiyang Zeng, Adrian Cernescu, Gabriel Landini, and Alexander Korsunsky. "Structure-Function Correlative Microscopy of Peritubular and Intertubular Dentine." Materials 11, no. 9 (August 21, 2018): 1493. http://dx.doi.org/10.3390/ma11091493.

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Peritubular dentine (PTD) and intertubular dentine (ITD) were investigated by 3D correlative Focused Ion Beam (FIB)-Scanning Electron Microscopy (SEM)-Energy Dispersive Spectroscopy (EDS) tomography, tapping mode Atomic Force Microscopy (AFM) and scattering-type Scanning Near-Field Optical Microscopy (s-SNOM) mapping. The brighter appearance of PTD in 3D SEM-Backscattered-Electron (BSE) imaging mode and the corresponding higher grey value indicate a greater mineral concentration in PTD (~160) compared to ITD (~152). However, the 3D FIB-SEM-EDS reconstruction and high resolution, quantitative 2D map of the Ca/P ratio (~1.8) fail to distinguish between PTD and ITD. This has been further confirmed using nanoscale 2D AFM map, which clearly visualised biopolymers and hydroxyapatite (HAp) crystallites with larger mean crystallite size in ITD (32 ± 8 nm) than that in PTD (22 ± 3 nm). Correlative microscopy reveals that the principal difference between PTD and ITD arises primarily from the nanoscale packing density of the crystallites bonded together by thin biopolymer, with moderate contribution from the chemical composition difference. The structural difference results in the mechanical properties variation that is described by the parabolic stiffness-volume fraction correlation function introduced here. The obtained results benefit a microstructure-based mechano-chemical model to simulate the chemical etching process that can occur in human dental caries and some of its treatments.
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22

Bakir, Gorkem, Benoit E. Girouard, Richard Wiens, Stefan Mastel, Eoghan Dillon, Mustafa Kansiz, and Kathleen M. Gough. "Orientation Matters: Polarization Dependent IR Spectroscopy of Collagen from Intact Tendon Down to the Single Fibril Level." Molecules 25, no. 18 (September 19, 2020): 4295. http://dx.doi.org/10.3390/molecules25184295.

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Infrared (IR) spectroscopy has been used for decades to study collagen in mammalian tissues. While many changes in the spectral profiles appear under polarized IR light, the absorption bands are naturally broad because of tissue heterogeneity. A better understanding of the spectra of ordered collagen will aid in the evaluation of disorder in damaged collagen and in scar tissue. To that end, collagen spectra have been acquired with polarized far-field (FF) Fourier Transform Infrared (FTIR) imaging with a Focal Plane Array detector, with the relatively new method of FF optical photothermal IR (O-PTIR), and with nano-FTIR spectroscopy based on scattering-type scanning near-field optical microscopy (s-SNOM). The FF methods were applied to sections of intact tendon with fibers aligned parallel and perpendicular to the polarized light. The O-PTIR and nano-FTIR methods were applied to individual fibrils of 100–500 nm diameter, yielding the first confirmatory and complementary results on a biopolymer. We observed that the Amide I and II bands from the fibrils were narrower than those from the intact tendon, and that both relative intensities and band shapes were altered. These spectra represent reliable profiles for normal collagen type I fibrils of this dimension, under polarized IR light, and can serve as a benchmark for the study of collagenous tissues.
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23

Amarie, Sergiu, Paul Zaslansky, Yusuke Kajihara, Erika Griesshaber, Wolfgang W. Schmahl, and Fritz Keilmann. "Nano-FTIR chemical mapping of minerals in biological materials." Beilstein Journal of Nanotechnology 3 (April 5, 2012): 312–23. http://dx.doi.org/10.3762/bjnano.3.35.

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Methods for imaging of nanocomposites based on X-ray, electron, tunneling or force microscopy provide information about the shapes of nanoparticles; however, all of these methods fail on chemical recognition. Neither do they allow local identification of mineral type. We demonstrate that infrared near-field microscopy solves these requirements at 20 nm spatial resolution, highlighting, in its first application to natural nanostructures, the mineral particles in shell and bone. "Nano-FTIR" spectral images result from Fourier-transform infrared (FTIR) spectroscopy combined with scattering scanning near-field optical microscopy (s-SNOM). On polished sections of Mytilus edulis shells we observe a reproducible vibrational (phonon) resonance within all biocalcite microcrystals, and distinctly different spectra on bioaragonite. Surprisingly, we discover sparse, previously unknown, 20 nm thin nanoparticles with distinctly different spectra that are characteristic of crystalline phosphate. Multicomponent phosphate bands are observed on human tooth sections. These spectra vary characteristically near tubuli in dentin, proving a chemical or structural variation of the apatite nanocrystals. The infrared band strength correlates with the mineral density determined by electron microscopy. Since nano-FTIR sensitively responds to structural disorder it is well suited for the study of biomineral formation and aging. Generally, nano-FTIR is suitable for the analysis and identification of composite materials in any discipline, from testing during nanofabrication to even the clinical investigation of osteopathies.
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24

Wang, Yuhong, Kecheng Zhao, Fangjin Li, Qi Gao, and King Wai Chiu Lai. "Recent advances in characterizing the “bee” structures and asphaltene particles in asphalt binders." International Journal of Pavement Research and Technology 13, no. 6 (November 2020): 697–706. http://dx.doi.org/10.1007/s42947-020-6008-3.

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AbstractThe microscopic surface features of asphalt binders are extensively reported in existing literature, but relatively fewer studies are performed on the morphology of asphaltene microstructures and cross-examination between the surface features and asphaltenes. This paper reports the findings of investigating six types of asphalt binders at the nanoscale, assisted with atomic force microscopy (AFM) and scanning transmission electron microscopy (STEM). The surface features of the asphalt binders were examined by using AFM before and after being repetitively peeled by a tape. Variations in infrared (IR) absorbance at the wavenumber around 1700 cm−1, which corresponds to ketones, were examined by using an infrared s-SNOM instrument (scattering-type scanning near-field optical microscope). Thin films of asphalt binders were examined by using STEM, and separate asphaltene particles were cross-examined by using both STEM and AFM. In addition, connections between the microstructures and binder’s physicochemical properties were evaluated. The use of both microscopy techniques provide comprehensive and complementary information on the microscopic nature of asphalt binders. It was found that the dynamic viscosities of asphalt binders are predominantly determined by the zero shear viscosity of the corresponding maltenes and asphaltene content. Limited samples also suggest that the unique bee structures are likely related to the growth of asphaltene content during asphalt binder aging process, but more asphalt binders from different crude sources are needed to verify this finding.
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25

Yu, Y., H. J. Li, and L. Li. "Reduction behavior of Tin-containing phase in Tin-bearing iron concentrates under CO-CO2 mixed gases." Journal of Mining and Metallurgy, Section B: Metallurgy 55, no. 2 (2019): 177–85. http://dx.doi.org/10.2298/jmmb181121025y.

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The main purpose of this study was to ascertain the reduction behavior of tin phase (SnO2) in tin-bearing iron concentrates at the respective temperature of 1273 and 1373 K in diverse CO-CO2 mixed gases using chemical analysis, XRD, and SEMEDS analysis. The results show that the reduction behavior of SnO2 depends on the roasting temperature and CO content. At 1273 K, the SnO2 will be reduced to Sn (l) with the CO content being higher than 17.26 vol%, and there is no formation of SnO(s). With the temperature increased to 1373 K, the SnO2 is reduced stepwise in the order to form SnO2 ? SnO (l) ? Sn(l) with CO content over 15.75 vol%. The kinetic study shows that activation energy of the reaction SnO2(s)+CO(g)=Sn(l)+ CO2(g) is 144.75 kJ/mol at 1073-1223 K, being far lower than the one in the reduction of SnO2(s) into SnO(g) at 1273-1323 K, which leads to a conclusion that the tin in tin-bearing iron concentrates could be removed effectively after the Sn(l) sulfurated into SnS at relatively lower temperatures (1073-1223 K) using the sulfidation roasting method.
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26

Goodings, John M., and QingFeng Chen. "Chemical kinetics and thermodynamics of tin ionization in H2-O2-N2 flames and the proton affinity of SnO." Canadian Journal of Chemistry 76, no. 10 (October 1, 1998): 1437–46. http://dx.doi.org/10.1139/v98-172.

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A small amount (<10-6 mol fraction) of tin was introduced into five, fuel-rich, H2-O2-N2 flames in the temperature range 1820-2400 K at atmospheric pressure. Ions in a flame were observed by sampling the flame along its axis through a nozzle into a mass spectrometer. The major neutral tin species in these flames were SnO (>97%) and Sn (<3%). The principal tin ions observed were SnOH+ and Sn+. Thermodynamic functions for SnOH+, Sn+, SnO, and Sn were calculated by statistical mechanics using published data from ab initio calculations and spectroscopy. The SnOH+ ion was formed initially by proton transfer to SnO by H3O+, a natural flame ion, with which it is in equilibrium. It was also produced by chemi-ionization of SnO reacting with H; SnOH+ rapidly equilibrates with Sn+. Ion ratio measurements of SnOH+/H3O+ led to the proton affinity PA°298 (SnO) = 911 ± 21 kJ mol -1 (218 ± 5 kcal mol-1). A calculated equilibrium constant provided the SnOH+/Sn+ ion ratio. When electron-ion recombination of SnOH+ with free electrons was made dominant by the addition of CH4 and K, the measured recombination coefficient of SnOH+ was (0.116 ± 0.065)T-(1.66±0.16) cm3 molecule-1 s-1; the temperature dependence is in good agreement with the T-1.5 dependence predicted by simple theory. The rate constant for chemi-ionization could not be measured due to impurity ions from potassium and sodium, but the equilibrium constant for chemi-ionization/recombination was calculated to be 0.004 863 exp (-52 070/T). Assuming detailed balance and the experimental recombination coefficient, the relatively small rate constant for chemi-ionization was given by 3.27 × 10-10 exp (-48 630/T) cm3 molecule-1 s-1. Finally, calculated values were obtained for the bond energy D°0(HO-Sn+) = 408 ± 21 kJ mol-1, and the standard zero-point enthalpy of formation deltafH°0(SnOH+) = 637 ± 21 kJ mol-1.Key words: flame ionization, chemi-ionization, proton affinity, mass spectrometry, tin.
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27

Sonveaux, Pierre, Irina I. Lobysheva, Olivier Feron, and Timothy J. McMahon. "Transport and Peripheral Bioactivities of Nitrogen Oxides Carried by Red Blood Cell Hemoglobin: Role in Oxygen Delivery." Physiology 22, no. 2 (April 2007): 97–112. http://dx.doi.org/10.1152/physiol.00042.2006.

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The biology of NO (nitric oxide) is poorly explained by the activity of the free radical NO (·NO) itself. Although·NO acts in an autocrine and paracrine manner, it is also in chemical equilibrium with other NO species that constitute stable stores of NO bioactivity. Among these species, S-nitrosylated hemoglobin ( S-nitrosohemoglobin; SNO-Hb) is an evolved transducer of NO bioactivity that acts in a responsive and exquisitely regulated manner to control cardiopulmonary and vascular homeostasis. In SNO-Hb, O2sensing is dynamically coupled to formation and release of vasodilating SNOs, endowing the red blood cell (RBC) with the capacity to regulate its own principal function, O2delivery, via regulation of blood flow. Analogous, physiological actions of RBC SNO-Hb also contribute to central nervous responses to blood hypoxia, the uptake of O2from the lung to blood, and baroreceptor-mediated control of the systemic flow of blood. Dysregulation of the formation, export, or actions of RBC-derived SNOs has been implicated in human diseases including sepsis, sickle cell anemia, pulmonary arterial hypertension, and diabetes mellitus. Delivery of SNOs by the RBC can be harnessed for therapeutic gain, and early results support the logic of this approach in the treatment of diseases as varied as cancer and neonatal pulmonary hypertension.
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28

Premont, Richard T., and Jonathan S. Stamler. "Essential Role of Hemoglobin βCys93 in Cardiovascular Physiology." Physiology 35, no. 4 (July 1, 2020): 234–43. http://dx.doi.org/10.1152/physiol.00040.2019.

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The supply of oxygen to tissues is controlled by microcirculatory blood flow. One of the more surprising discoveries in cardiovascular physiology is the critical dependence of microcirculatory blood flow on a single conserved cysteine within the β-subunit (βCys93) of hemoglobin (Hb). βCys93 is the primary site of Hb S-nitrosylation [i.e., S-nitrosothiol (SNO) formation to produce S-nitrosohemoglobin (SNO-Hb)]. Notably, S-nitrosylation of βCys93 by NO is favored in the oxygenated conformation of Hb, and deoxygenated Hb releases SNO from βCys93. Since SNOs are vasodilatory, this mechanism provides a physiological basis for how tissue hypoxia increases microcirculatory blood flow (hypoxic autoregulation of blood flow). Mice expressing βCys93A mutant Hb (C93A) have been applied to understand the role of βCys93, and RBCs more generally, in cardiovascular physiology. Notably, C93A mice are unable to effect hypoxic autoregulation of blood flow and exhibit widespread tissue hypoxia. Moreover, reactive hyperemia (augmentation of blood flow following transient ischemia) is markedly impaired. C93A mice display multiple compensations to preserve RBC vasodilation and overcome tissue hypoxia, including shifting SNOs to other thiols on adult and fetal Hbs and elsewhere in RBCs, and growing new blood vessels. However, compensatory vasodilation in C93A mice is uncoupled from hypoxic control, both peripherally (e.g., predisposing to ischemic injury) and centrally (e.g., impairing hypoxic drive to breathe). Altogether, physiological studies utilizing C93A mice are confirming the allosterically controlled role of SNO-Hb in microvascular blood flow, uncovering essential roles for RBC-mediated vasodilation in cardiovascular physiology and revealing new roles for RBCs in cardiovascular disease.
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29

Dosier, Laura Beth Mann, Vikram J. Premkumar, Hongmei Zhu, Izzet Akosman, Michael F. Wempe, and Timothy J. McMahon. "Antagonists of the system L neutral amino acid transporter (LAT) promote endothelial adhesivity of human red blood cells." Thrombosis and Haemostasis 117, no. 07 (2017): 1402–11. http://dx.doi.org/10.1160/th16-05-0373.

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SummaryThe system L neutral amino acid transporter (LAT; LAT1, LAT2, LAT3, or LAT4) has multiple functions in human biology, including the cellular import of S-nitrosothiols (SNOs), biologically active derivatives of nitric oxide (NO). SNO formation by haemoglobin within red blood cells (RBC) has been studied, but the conduit whereby a SNO leaves the RBC remains unidentified. Here we hypothesised that SNO export by RBCs may also depend on LAT activity, and investigated the role of RBC LAT in modulating SNO-sensitive RBC-endothelial cell (EC) adhesion. We used multiple pharmacologic inhibitors of LAT in vitro and in vivo to test the role of LAT in SNO export from RBCs and in thereby modulating RBC-EC adhesion. Inhibition of human RBC LAT by type-1-specific or nonspecific LAT antagonists increased RBC-endothelial adhesivity in vitro, and LAT inhibitors tended to increase post-transfusion RBC sequestration in the lung and decreased oxygenation in vivo. A LAT1-specific inhibitor attenuated SNO export from RBCs, and we demonstrated LAT1 in RBC membranes and LAT1 mRNA in reticulocytes. The proadhesive effects of inhibiting LAT1 could be overcome by supplemental L-CSNO (S-nitroso-L-cysteine), but not D-CSNO or L-Cys, and suggest a basal anti-adhesive role for stereospecific intercellular SNO transport. This study reveals for the first time a novel role of LAT1 in the export of SNOs from RBCs to prevent their adhesion to ECs. The findings have implications for the mechanisms of intercellular SNO signalling, and for thrombosis, sickle cell disease, and post-storage RBC transfusion, when RBC adhesivity is increased.
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30

Jingqin, Wang, Liu Zhou, Chen Ling, Yu Shuangmiao, and Zhu Yancai. "Effect of Cu, S Co-Doping on Properties of AgSnO2 Contact Material." Science of Advanced Materials 12, no. 8 (August 1, 2020): 1242–51. http://dx.doi.org/10.1166/sam.2020.3757.

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The stability, elastic properties and conductive properties of Cu-doped SnO2, S-doped SnO2 and Cu, S-codoped SnO 2were studied by using the first-principles calculation method based on the density functional theory. The corresponding doped SnO2 powders were prepared by sol–gel method, while AgSnO2–Cu and AgSnO2–Cu–S contacts were obtained by powder metallurgy method for experimental verification. No diffraction peaks were associated with Cu and S in the XRD patterns of the doped SnO2 powders, indicating that the doped SnO2 retained the tetragonal crystal structure. The doping formation energy of Cu, S co-doped system was found to be lower than that of Cu single doping system and S single doping system. The bulk modulus, shear modulus and Young's modulus of the co-doped system became lower, the ability to resist compression deformation and shear deformation was also weakened, while its toughness was greatly improved. The hardness of the AgSnO2–Cu–S contact was 103.55 HV, which is less than the hardness of the AgSnO2–Cu contact (112.86 HV). The calculations indicated that Cu, S co-doping could narrow the band gap, reduce the hole effective mass and the acceptor ionization energy, improve the hole mobility, and enhance the conductivity of the material. The electrical contact simulation experiments showed that the conductive properties, arc corrosion resistance and welding resistance of AgSnO2–Cu–S contact were better than those of the AgSnO2–Cu contact. The conductivity of AgSnO2–Cu–S contact was 29.948 mS · m–1, the contact resistance was 1.109 Ωm ; the average arc duration and average arc energy were 1.480 ms and 171.65 mJ, respectively.
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31

Kay, Jackie. "Glasgow Snow (for S)." Callaloo 37, no. 2 (2014): 263–64. http://dx.doi.org/10.1353/cal.2014.0050.

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32

Nogueira, Leonardo, Cicero Figueiredo-Freitas, Gustavo Casimiro-Lopes, Margaret H. Magdesian, Jamil Assreuy, and Martha M. Sorenson. "Myosin is reversibly inhibited by S-nitrosylation." Biochemical Journal 424, no. 2 (November 11, 2009): 221–31. http://dx.doi.org/10.1042/bj20091144.

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Nitric oxide (NO•) is synthesized in skeletal muscle and its production increases during contractile activity. Although myosin is the most abundant protein in muscle, it is not known whether myosin is a target of NO• or NO• derivatives. In the present study, we have shown that exercise increases protein S-nitrosylation in muscle, and, among contractile proteins, myosin is the principal target of exogenous SNOs (S-nitrosothiols) in both skinned skeletal muscle fibres and differentiated myotubes. The reaction of isolated myosin with S-nitrosoglutathione results in S-nitrosylation at multiple cysteine thiols and produces two populations of protein-bound SNOs with different stabilities. The less-stable population inhibits the physiological ATPase activity, without affecting the affinity of myosin for actin. However, myosin is neither inhibited nor S-nitrosylated by the NO• donor diethylamine NONOate, indicating a requirement for transnitrosylation between low-mass SNO and myosin cysteine thiols rather than a direct reaction of myosin with NO• or its auto-oxidation products. Interestingly, alkylation of the most reactive thiols of myosin by N-ethylmaleimide does not inhibit formation of a stable population of protein-SNOs, suggesting that these sites are located in less accessible regions of the protein than those that affect activity. The present study reveals a new link between exercise and S-nitrosylation of skeletal muscle contractile proteins that may be important under (patho)physiological conditions.
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33

Kaupp, Gerd, Andreas Herrmann, and Michael Haak. "Artifacts in scanning near-field optical microscopy (SNOM) due to deficient tips." Journal of Physical Organic Chemistry 12, no. 11 (November 1999): 797–807. http://dx.doi.org/10.1002/(sici)1099-1395(199911)12:11<797::aid-poc204>3.0.co;2-s.

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34

Vrancken, Kurt, Hobe J. Schroeder, Lawrence D. Longo, Gordon G. Power, and Arlin B. Blood. "Role of ceruloplasmin in nitric oxide metabolism in plasma of humans and sheep: a comparison of adults and fetuses." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 305, no. 11 (December 1, 2013): R1401—R1410. http://dx.doi.org/10.1152/ajpregu.00266.2013.

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Nitric oxide (NO) is metabolized in plasma, in part by the ferroxidase ceruloplasmin (Cp), to form nitrite and nitrosothiols (SNOs), which are proposed to mediate protective responses to hypoxia and ischemia. We hypothesized that NO metabolism would be attenuated in fetal plasma due to low Cp activity. We measured Cp concentrations and activity in plasma samples collected from adults and fetuses of humans and sheep. We then added NO ([NO]: 1.5 or 100 μM) to plasma and aqueous buffer and measured rates of NO disappearance and the production of nitrite and SNO. Cp concentrations in fetal plasma were <15% of adult levels. In aqueous buffer, 1.5 μM NO disappeared with a half-life of 347 ± 64 s (means ± SE) but in plasma of humans the half-life was 19 ± 2 s (adult) and 11 ± 1 s (fetus, P = 0.004) and in sheep it was 31 ± 3 s (adult) and 43 ± 5 s (fetus, P = 0.04). Cp activity was not correlated with the overall elimination half-life of NO or with the amount of SNO ([NO]: 100 μM) or nitrite ([NO]: 1.5 or 100 μM) produced but correlated with SNO yields at 1.5 μM [NO] ( r = 0.92, P = 0.04). Our data demonstrate that Cp is not essential to the increased rate of metabolism of NO in plasma relative to aqueous buffers and that it is not essential to the production of nitrite from NO. Cp may be involved in the conversion of NO to SNO in plasma under near-physiological concentrations of NO.
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35

Zhao, Pei Tang, Zhi Ming Du, Li Dong Wang, and Wei Dong Fei. "Effect of SnO2 Coating on the Low Temperature Extrusion of 6061Al Matrix Composite Reinforced with Aluminum Borate Whisker." Advanced Materials Research 299-300 (July 2011): 692–95. http://dx.doi.org/10.4028/www.scientific.net/amr.299-300.692.

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The 6061Al matrix composites reinforced with SnO2-coated aluminum borate whisker were fabricated using squeeze casting method. The composites with different SnO2 coating contents were extruded successfully at 350°C with the extrusion rate of 18mm/s. The results show that the Sn particles at the interface as liquid state at extrusion temperature result in the reduction of the extrusion load and the decrease of the probability of whisker fracture during hot deformation process. Moreover, unlike many surface cracks can be seen in the extruded composite without whisker coating, the surface crack-free extruded rods can be obtained for composites with whisker coating. The ABOW/SnO/6061Al composites tensile properties increased obviously after extrusion.
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36

Jankov, Robert P., Kathrine L. Daniel, Shira Iny, Crystal Kantores, Julijana Ivanovska, Nadya Ben Fadel, and Amish Jain. "Sodium nitrite augments lung S-nitrosylation and reverses chronic hypoxic pulmonary hypertension in juvenile rats." American Journal of Physiology-Lung Cellular and Molecular Physiology 315, no. 5 (November 1, 2018): L742—L751. http://dx.doi.org/10.1152/ajplung.00184.2018.

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Deficient nitric oxide (NO) signaling plays a critical role in the pathogenesis of chronic neonatal pulmonary hypertension (PHT). Physiological NO signaling is regulated by S-nitrosothiols (SNOs), which act both as a reservoir for NO and as a reversible modulator of protein function. We have previously reported that therapy with inhaled NO (iNO) increased peroxynitrite-mediated nitration in the juvenile rat lung, although having minimal reversing effects on vascular remodeling. We hypothesized that sodium nitrite (NaNO2) would be superior to iNO in enhancing lung SNOs, thereby contributing to reversal of chronic hypoxic PHT. Rat pups were exposed to air or hypoxia (13% O2) from postnatal days 1 to 21. Dose-response prevention studies were conducted from days 1–21 to determine the optimal dose of NaNO2. Animals then received rescue therapy with daily subcutaneous NaNO2 (20 mg/kg), vehicle, or were continuously exposed to iNO (20 ppm) from days 14–21. Chronic PHT secondary to hypoxia was both prevented and reversed by treatment with NaNO2. Rescue NaNO2 increased lung NO and SNO contents to a greater extent than iNO, without causing nitration. Seven lung SNO proteins upregulated by treatment with NaNO2 were identified by multiplex tandem mass tag spectrometry, one of which was leukotriene A4 hydrolase (LTA4H). Rescue therapy with a LTA4H inhibitor, SC57461A (10 mg·kg−1·day−1 sc), partially reversed chronic hypoxic PHT. We conclude that NaNO2 was superior to iNO in increasing tissue NO and SNO generation and reversing chronic PHT, in part via upregulated SNO-LTA4H.
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37

Hu, Weidong, Jing Wu, Yunhong Jiao, Jixing Xie, Jinjie Chen, and Jianzhong Xu. "Synthesis of hollow tin dioxide and its improvement of flame retardancy and toughness on poly(vinyl chloride)." Journal of Fire Sciences 37, no. 1 (November 29, 2018): 67–80. http://dx.doi.org/10.1177/0734904118815056.

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Hollow tin dioxide (S-SnO2) and solid SnO2 (B-SnO2) were prepared by a hydrothermal-calcination method with and without carbon spheres as templates, respectively. The flame retardancy, mechanical and thermal degradation properties, and char residues of the poly(vinyl chloride) samples treated with S-SnO2 and B-SnO2 were contrastively investigated by a limiting oxygen index instrument, cone calorimeter (Cone), tensile properties tests, and thermogravimetric analyzer. When the loading level of SnO2 was 2 phr, the limiting oxygen index of the poly(vinyl chloride) sample treated with S-SnO2 (poly(vinyl chloride)/S-SnO2) increased by 5.3% and 2%, and its elongation is 27.3% and 29.9% higher than that of the blank poly(vinyl chloride) and the poly(vinyl chloride) sample treated with B-SnO2 (poly(vinyl chloride)/B-SnO2), respectively. Compared with the blank poly(vinyl chloride) and the poly(vinyl chloride)/B-SnO2, the total heat release of poly(vinyl chloride)/S-SnO2 decreased by 24.5% and 9.4%, and the peak of smoke production rate decreased by 56.7% and 11.7%, respectively.
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38

Shrestha, M., L. Wang, T. Koike, Y. Xue, and Y. Hirabayashi. "Improving the snow physics of WEB-DHM and its point evaluation at two SnowMIP alpine sites." Hydrology and Earth System Sciences Discussions 7, no. 3 (June 15, 2010): 3481–519. http://dx.doi.org/10.5194/hessd-7-3481-2010.

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Abstract. The snow physics of a distributed biosphere hydrological model, referred to as the Water and Energy Budget based Distributed Hydrological Model (WEB-DHM) is improved by incorporating the three-layer physically based energy balance snowmelt model of Simplified Simple Biosphere 3 (SSiB3) and the Biosphere-Atmosphere Transfer Scheme (BATS) albedo scheme. WEB-DHM with improved snow physics (WEB-DHM-S) can simulate the variability of snow density, snow depth and snow water equivalent, liquid water and ice content in each layer, prognostic snow albedo, diurnal variation in snow surface temperature, thermal heat due to conduction and liquid water retention. The performance of WEB-DHM-S is evaluated at two alpine sites of the Snow Model Intercomparison Project with different climate characteristics: Col de Porte in France and Weissfluhjoch in Switzerland. The simulation results of the snow depth, snow water equivalent, surface temperature, snow albedo and snowmelt runoff reveal that WEB-DHM-S is capable of simulating the internal snow process better than the original WEB-DHM, with the root mean square error and bias error being remarkably reduced. Although WEB-DHM-S is only evaluated at a point scale for the simulation of snow processes, this study provides a benchmark for the application of WEB-DHM-S in cold regions in the assessment of the basin-scale snow water equivalent and seasonal discharge simulation for water resources management.
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39

&NA;. "John Snow???s Practice of Obstetric Anesthesia." Survey of Anesthesiology 45, no. 1 (February 2001): 68. http://dx.doi.org/10.1097/00132586-200102000-00066.

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40

Gagné, Christina L., Thomas L. Spalding, Lauren Figueredo, and Allison C. Mullaly. "Does s now man prime plastic snow?" Mental Lexicon 4, no. 1 (April 24, 2009): 41–76. http://dx.doi.org/10.1075/ml.4.1.03gag.

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Three experiments were conducted to determine the extent to which relational and morphosyntactic information influence the processing of modifier-noun phrases. Processing of the target was faster when the shared constituent was in the same position in both the prime and the target, regardless of whether the relation was the same or different. In contrast, relation priming was contingent on the morphosyntactic role of the shared constituent; repeating the relation with the constituent in a different morphosyntactic role did not speed processing of the target (Experiments 1–3) whereas repeating the relation with the constituent in the same role did speed processing (Experiments 3). These results suggest that conceptual information is accessed in light of the constituent’s particular morphosyntactic role.
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41

McMahon, Timothy J., Siqing Shan, Daniel A. Riccio, Milena Batchvarova, Hongmei Zhu, Marilyn J. Telen, and Rahima Zennadi. "Nitric oxide loading reduces sickle red cell adhesion and vaso-occlusion in vivo." Blood Advances 3, no. 17 (September 4, 2019): 2586–97. http://dx.doi.org/10.1182/bloodadvances.2019031633.

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Abstract Sickle red blood cells (SSRBCs) are adherent to the endothelium, activate leukocyte adhesion, and are deficient in bioactive nitric oxide (NO) adducts such as S-nitrosothiols (SNOs), with reduced ability to induce vasodilation in response to hypoxia. All these pathophysiologic characteristics promote vascular occlusion, the hallmark of sickle cell disease (SCD). Loading hypoxic SSRBCs in vitro with NO followed by reoxygenation significantly decreased epinephrine-activated SSRBC adhesion to the endothelium, the ability of activated SSRBCs to mediate leukocyte adhesion in vitro, and vessel obstruction in vivo. Because transfusion is frequently used in SCD, we also determined the effects of banked (SNO-depleted) red blood cells (RBCs) on vaso-occlusion in vivo. Fresh or 14-day-old normal RBCs (AARBCs) reduced epinephrine-activated SSRBC adhesion to the vascular endothelium and prevented vaso-occlusion. In contrast, AARBCs stored for 30 days failed to decrease activated SSRBC adhesivity or vaso-occlusion, unless these RBCs were loaded with NO. Furthermore, NO loading of SSRBCs increased S-nitrosohemoglobin and modulated epinephrine’s effect by upregulating phosphorylation of membrane proteins, including pyruvate kinase, E3 ubiquitin ligase, and the cytoskeletal protein 4.1. Thus, abnormal SSRBC NO/SNO content both contributes to the vaso-occlusive pathophysiology of SCD, potentially by affecting at least protein phosphorylation, and is potentially amenable to correction by (S)NO repletion or by RBC transfusion.
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42

Bean, Laura E., William H. Dvorachek, Edward L. Braun, Allison Errett, Gregory S. Saenz, Mara D. Giles, Margaret Werner-Washburne, Mary Anne Nelson, and Donald O. Natvig. "Analysis of thepdx-1(snz-1/sno-1) Region of theNeurospora crassaGenome: Correlation of Pyridoxine-Requiring Phenotypes With Mutations in Two Structural Genes." Genetics 157, no. 3 (March 1, 2001): 1067–75. http://dx.doi.org/10.1093/genetics/157.3.1067.

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AbstractWe report the analysis of a 36-kbp region of the Neurospora crassa genome, which contains homologs of two closely linked stationary phase genes, SNZ1 and SNO1, from Saccharomyces cerevisiae. Homologs of SNZ1 encode extremely highly conserved proteins that have been implicated in pyridoxine (vitamin B6) metabolism in the filamentous fungi Cercospora nicotianae and in Aspergillus nidulans. In N. crassa, SNZ and SNO homologs map to the region occupied by pdx-1 (pyridoxine requiring), a gene that has been known for several decades, but which was not sequenced previously. In this study, pyridoxine-requiring mutants of N. crassa were found to possess mutations that disrupt conserved regions in either the SNZ or SNO homolog. Previously, nearly all of these mutants were classified as pdx-1. However, one mutant with a disrupted SNO homolog was at one time designated pdx-2. It now appears appropriate to reserve the pdx-1 designation for the N. crassa SNZ homolog and pdx-2 for the SNO homolog. We further report annotation of the entire 36,030-bp region, which contains at least 12 protein coding genes, supporting a previous conclusion of high gene densities (12,000-13,000 total genes) for N. crassa. Among genes in this region other than SNZ and SNO homologs, there was no evidence of shared function. Four of the genes in this region appear to have been lost from the S. cerevisiae lineage.
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43

McMahon, Timothy J. "Functional and Biochemical Changes in Stored Human Red Blood Cells." Blood 112, no. 11 (November 16, 2008): sci—49—sci—49. http://dx.doi.org/10.1182/blood.v112.11.sci-49.sci-49.

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Abstract Transfusion of red blood cells (RBCs) is associated with excess mortality and morbidity in some anemic patients with critical illness, and no benefit in others, but the underlying mechanisms are poorly understood. Specifically, little is known of how “storage lesions” of the RBC may contribute to adverse outcomes or lack of benefit from a transfusion. The recent discovery of an active role of the human RBC in regulating blood flow – a major determinant of its own function, O2 delivery – prompts a reexamination of storage-induced changes in this and related RBC functions, and motivates specific identification of the relevant mediators. RBCs release the vasodilators S-nitrosothiols (SNOs) and ATP upon physiological exposure to hypoxia, contributing to O2-dependent blood flow regulation. The result is hypoxic vasodilation peripherally and modulation of hypoxic vasoconstriction in the lung. We show that conventionally stored human RBCs become deficient in SNOs within three hours of acquisition and independent of exposure to storage solution or leukofiltration; both hemoglobin-bound SNO and membrane SNO are depressed. Early changes (hours) are also seen in the function of stored RBCs, namely in RBC regulation of vascular tone in vitro and in the lungs of intact mice in vivo, whereas declines in RBC deformability take place more gradually (from days to weeks). We also confirm storage-induced depletion of RBC ATP, a lesion which may contribute to the functional declines in both deformability and in RBC-dependent vasoactivity. Time courses, therefore, vary widely for several storage-induced functional and biochemical defects that may contribute to adverse clinical outcomes following RBC transfusion. Strategies that either prevent the loss of vasoactive mediators during RBC storage, or replete bioactive (S)NO after RBC storage, are reviewed and may inform the rational design of strategies to improve the risk-benefit balance associated with RBC transfusion in critically ill and other anemic patients.
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44

Price, Michael E., Jacqueline A. Pavlik, Miao Liu, Shi-Jian Ding, Todd A. Wyatt, and Joseph H. Sisson. "Alcohol drives S-nitrosylation and redox activation of protein phosphatase 1, causing bovine airway cilia dysfunction." American Journal of Physiology-Lung Cellular and Molecular Physiology 312, no. 3 (March 1, 2017): L432—L439. http://dx.doi.org/10.1152/ajplung.00513.2016.

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Individuals with alcohol (ethanol)-use disorders are at increased risk for lung infections, in part, due to defective mucociliary clearance driven by motile cilia in the airways. We recently reported that isolated, demembranated bovine cilia (axonemes) are capable of producing nitric oxide (∙NO) when exposed to biologically relevant concentrations of alcohol. This increased presence of ∙NO can lead to protein S-nitrosylation, a posttranslational modification signaling mechanism involving reversible adduction of nitrosonium cations or ∙NO to thiolate or thiyl radicals, respectively, of proteins forming S-nitrosothiols (SNOs). We quantified and compared SNO content between isolated, demembranated axonemes extracted from bovine tracheae, with or without in situ alcohol exposure (100 mM × 24 h). We demonstrate that relevant concentrations of alcohol exposure shift the S-nitrosylation status of key cilia regulatory proteins, including 20-fold increases in S-nitrosylation of proteins that include protein phosphatase 1 (PP1). With the use of an ATP-reactivated axoneme motility system, we demonstrate that alcohol-driven S-nitrosylation of PP1 is associated with PP1 activation and dysfunction of axoneme motility. These new data demonstrate that alcohol can shift the S-nitrothiol balance at the level of the cilia organelle and highlight S-nitrosylation as a novel signaling mechanism to regulate PP1 and cilia motility.
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45

Saavedra, Freddy A., Stephanie K. Kampf, Steven R. Fassnacht, and Jason S. Sibold. "Changes in Andes snow cover from MODIS data, 2000–2016." Cryosphere 12, no. 3 (March 23, 2018): 1027–46. http://dx.doi.org/10.5194/tc-12-1027-2018.

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Abstract. The Andes span a length of 7000 km and are important for sustaining regional water supplies. Snow variability across this region has not been studied in detail due to sparse and unevenly distributed instrumental climate data. We calculated snow persistence (SP) as the fraction of time with snow cover for each year between 2000 and 2016 from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite sensors (500 m, 8-day maximum snow cover extent). This analysis is conducted between 8 and 36∘ S due to high frequency of cloud (> 30 % of the time) south and north of this range. We ran Mann–Kendall and Theil–Sens analyses to identify areas with significant changes in SP and snowline (the line at lower elevation where SP = 20 %). We evaluated how these trends relate to temperature and precipitation from Modern-Era Retrospective Analysis for Research and Applications-2 (MERRA2) and University of Delaware datasets and climate indices as El Niño–Southern Oscillation (ENSO), Southern Annular Mode (SAM), and Pacific Decadal Oscillation (PDO). Areas north of 29∘ S have limited snow cover, and few trends in snow persistence were detected. A large area (34 370 km2) with persistent snow cover between 29 and 36∘ S experienced a significant loss of snow cover (2–5 fewer days of snow year−1). Snow loss was more pronounced (62 % of the area with significant trends) on the east side of the Andes. We also found a significant increase in the elevation of the snowline at 10–30 m year−1 south of 29–30∘ S. Decreasing SP correlates with decreasing precipitation and increasing temperature, and the magnitudes of these correlations vary with latitude and elevation. ENSO climate indices better predicted SP conditions north of 31∘ S, whereas the SAM better predicted SP south of 31∘ S.
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46

Kobayashi, Shun’Ichi, Nobuyoshi Ishikawa, and Tetsuo Ohata. "Katabatic Snow Storms in Stable Atmospheric Conditions at Mizuho Station, Antarctica." Annals of Glaciology 6 (1985): 229–31. http://dx.doi.org/10.3189/1985aog6-1-229-231.

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This paper describes the results of snow drift measurements made on a strong katabatic wind slope at Mizuho Station (70°42.6’S, 44°18.9’E; 2230 m above mean sea level) in East Antarctica. From the vertical profile of the mass flux of blowing snow up to 28 m above the snow surface under conditions of snow fall, the snow fall densitities have been estimated as asymptotes of the profile (Fohn 1980). Snow fall densities as asymptotes were estimated between 8x10-6 and 8xl0-5 kg/m3. Assuming a fall velocity of blowing snow particles as 0.5 m/s, above values correspond to values of the vertical flux of snow fall between 2x10-3 and 1.5xl0-1 mm/h.
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47

Kobayashi, Shun’Ichi, Nobuyoshi Ishikawa, and Tetsuo Ohata. "Katabatic Snow Storms in Stable Atmospheric Conditions at Mizuho Station, Antarctica." Annals of Glaciology 6 (1985): 229–31. http://dx.doi.org/10.1017/s0260305500010429.

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This paper describes the results of snow drift measurements made on a strong katabatic wind slope at Mizuho Station (70°42.6’S, 44°18.9’E; 2230 m above mean sea level) in East Antarctica. From the vertical profile of the mass flux of blowing snow up to 28 m above the snow surface under conditions of snow fall, the snow fall densitities have been estimated as asymptotes of the profile (Fohn 1980). Snow fall densities as asymptotes were estimated between 8x10-6and 8xl0-5kg/m3. Assuming a fall velocity of blowing snow particles as 0.5 m/s, above values correspond to values of the vertical flux of snow fall between 2x10-3and 1.5xl0-1mm/h.
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48

Yu, Jianyuan, Yingeng Wang, Yan Huang, Xiuwen Wang, Jing Guo, Jingkai Yang, and Hongli Zhao. "Structural and electronic properties of SnO2 doped with non-metal elements." Beilstein Journal of Nanotechnology 11 (September 3, 2020): 1321–28. http://dx.doi.org/10.3762/bjnano.11.116.

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Crystal structure and electronic properties of SnO2 doped with non-metal elements (F, S, C, B, and N) were studied using first-principles calculations. The theoretical results show that doping of non-metal elements cannot change the structure of SnO2 but result in a slight expansion of the lattice volume. The most obvious finding from the analysis is that F-doped SnO2 has the lowest defect binding energy. The doping with B and S introduced additional defect energy levels within the forbidden bandgap, which improved the crystal conductivity. The Fermi level shifts up due to the doping with B, F, and S, while the Fermi level of SnO2 doped with C or N has crossed the impurity level. The Fermi level of F-doped SnO2 is inside the conduction band, and the doped crystal possesses metallicity. The optical properties of SnO2 crystals doped with non-metal elements were analyzed and calculated. The SnO2 crystal doped with F had the highest reflectivity in the infrared region, and the reflectance of the crystals doped with N, C, S, and B decreased sequentially. Based on this theoretical calculations, F-doped SnO2 is found to be the best photoelectric material for preparing low-emissivity coatings.
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49

Gan, Sin Yee, K. K. Lim, M. A. A. Hamid, R. Shamsudin, and W. S. Chiu. "Synthesis and Characterization of SnO2 and Fe3O4 Composite Grown by Microwave Method." Advanced Materials Research 895 (February 2014): 291–97. http://dx.doi.org/10.4028/www.scientific.net/amr.895.291.

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In this research, SnO2 and Fe3O4 composite thin film were grown on glass slides by using commercial microwave oven. The obtained samples were characterized using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDX), Ultraviolet-Visible Spectroscopy (UV-Vis) and Photoluminescence (PL). The growth of SnO2 was carried out for the periods of 60 s, 50 s and 40 s with two 5-second time intervals. XRD pattern shows the presence of two phases: SnO2 and Fe3O4 in all samples of grown composites. It was found that the sample grown for 60 s having dominant SnO2 phase while for the durations of 40 s and 50 s, the phase of Fe3O4 are more dominant. The Fe3O4s phases are believed originated from chemical reaction involving the steel wool which was used to stimulate the oxidation of Sn into SnO2. SEM observations reveal heavily agglomerated spherical-like particles which size ranges from 80.6 nm to 113.6 nm. EDX analysis indicates that composites with the growth time of 60 s contain the highest weight percentage (13.52 %) of Sn, followed by those composites with the growth time of 50 s (5.47 %) and 40 s (4.31 %). UV-Vis spectroscopy shows the optical band gap energy for the 60-second growth times composite, is 3.9 eV, which is well-correlated with the value of bulk of SnO2.PL characterization shows that the peaks of the curve fall within the range between 490 nm and 900 nm. The presence of oxygen defects probably causes the deterioration of optical bandwidth. Keywords: Thin film, tin dioxide, domestic microwave
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50

Bukovčić, Petar, Alexander Ryzhkov, Dusan Zrnić, and Guifu Zhang. "Polarimetric Radar Relations for Quantification of Snow Based on Disdrometer Data." Journal of Applied Meteorology and Climatology 57, no. 1 (January 2018): 103–20. http://dx.doi.org/10.1175/jamc-d-17-0090.1.

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AbstractAccurate measurements of snow amounts by radar are very difficult to achieve. The inherent uncertainty in radar snow estimates that are based on the radar reflectivity factor Z is caused by the variability of snow particle size distributions and snow particle density as well as the large diversity among snow growth habits. In this study, a novel method for snow quantification that is based on the joint use of radar reflectivity Z and specific differential phase KDP is introduced. An extensive dataset of 2D-video-disdrometer measurements of snow in central Oklahoma is used to derive polarimetric relations for liquid-equivalent snowfall rate S and ice water content IWC in the forms of bivariate power-law relations S = and along with similar relations for the intercept N0s and slope Λs of the exponential snow size distribution. The physical basis of these relations is explained. Their multipliers are sensitive to variations in the width of the canting angle distribution and to a lesser extent the particles’ aspect ratios and densities, whereas the exponents are practically invariant. This novel approach is tested against the S(Z) relation using snow disdrometer measurements in three geographical regions (Oklahoma, Colorado, and Canada). Significant improvement in snow estimates relative to the traditional Z-based methods is demonstrated.
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