Results 101 to 110 of about 8,769 (263)

CO2 and N2O Emissions From Vehicles in Seoul Megacity, South Korea: Insights From Mixing Ratio and Stable Isotope Ratios

Rapid Communications in Mass Spectrometry, Volume 40, Issue 18, 30 September 2026.
ABSTRACT Rationale Vehicular traffic is a major source of anthropogenic greenhouse gases in megacities; however, real‐world constraints on vehicle‐derived N2O emissions and their isotopic characteristics remain limited. Methods Air samples were collected from three tunnels and urban background sites (a university campus and mountain) in Seoul, South ...
Jeongeun Kim, Jinho Ahn, Sambit Ghosh, Sakae Toyoda, Shinji Morimoto, Hyunsuk Choi, Jaehoen Jung, Hungyu Lee   +7 more
wiley   +1 more source

Cryogen‐Aided Chromatographic Purification of Millimole Quantities of Methane for Spectroscopic Clumped Isotope Analysis

Rapid Communications in Mass Spectrometry, Volume 40, Issue 18, 30 September 2026.
ABSTRACT Rationale Quantum cascade laser absorption spectroscopy (QCLAS) is a fast and reliable method for analyzing the bulk (𝛿13C‐CH4, 𝛿D‐CH4) and clumped isotopic (∆13CH3D and ∆12CH2D2) composition of methane. However, precise measurements of ∆12CH2D2 require 0.5 to 1.8 mmol of purified methane (equivalent to 15 to 40 mL at STP).
Nico Kueter, Jan G. C. Meissner, Naizhong Zhang, Léna Msonnereau, Lukas Emmenegger, Joachim Mohn, Stefano M. Bernasconi   +6 more
wiley   +1 more source

Reaffirming the Consistency of the Original Stock of NBS 19 Limestone and Its Byproduct With Finer Grain Size for δ13C and δ18O Calibrations—Both Distributed Internationally

Rapid Communications in Mass Spectrometry, Volume 40, Issue 18, 30 September 2026.
ABSTRACT Rationale Approximately 3–4 kg of NBS 19 limestone, prepared in 1982 by the U.S. Geological Survey (USGS), serves as a primary reference for the carbon isotope scales VPDB and VPDB‐LSVEC and the oxygen isotope scale VPDB. Its consensus values are +1.95‰ for δ13C and −2.2‰ for δ18O measurements.
Haiping Qi, Tyler B. Coplen, Lauren T. Reid, Stanley J. Mroczkowski   +3 more
wiley   +1 more source

Three New Calcium Formate Reference Materials for δ13C Measurements and a Redetermination of the R(13C/12C) Ratio for VPDB Based on Proton Nuclear Magnetic Resonance Measurements

Rapid Communications in Mass Spectrometry, Volume 40, Issue 18, 30 September 2026.
ABSTRACT Rationale Isotope ratio mass spectrometry (IRMS) and proton nuclear magnetic resonance (1H NMR) spectroscopy are independent techniques for determining the isotope ratio R(13C/12C) in organic compounds. However, the lack of suitable reference materials has limited intercalibration of results from these methods.
David W. Hoffman, Cornelia Rasmussen, Arndt Schimmelmann, Lauren T. Reid, Haiping Qi, Tyler B. Coplen   +5 more
wiley   +1 more source

Organic‐matter sources and stability in kettle‐hole sediments: A combined thermogravimetric and isotopic approach

Agrosystems, Geosciences &Environment, Volume 9, Issue 3, September 2026.
Abstract Kettle‐holes are small but biogeochemically active landscape elements that integrate terrestrial inputs and influence carbon and nitrogen cycling. However, the stability and sources of organic matter (OM) in kettle‐hole sediments remain poorly understood.
Safdar Bashir, Kai Nils Nitzsche, Zachary Kayler   +2 more
wiley   +1 more source

Radiographic Indications for Orbital Blowout Fracture Reconstruction: A Critical Review of 2 Decades of Literature. [PDF]

Plast Reconstr Surg Glob Open
Hashem AM, MacKenzie J, Flores A, Nikolli K, Rayham J, Chamma B, Papay F.   +6 more
europepmc   +1 more source

Multicontinuum Homogenization for Poroelasticity Model

International Journal for Numerical Methods in Fluids, Volume 98, Issue 9, Page 1035-1060, September 2026.
This work derives a generalized multicontinuum poroelasticity model using the multicontinuum homogenization method to enable accurate coarse‐grid simulations of coupled flow–mechanics processes in highly heterogeneous porous media. Coupled constraint cell problems are formulated, and the corresponding multicontinuum equations are rigorously derived ...
Dmitry Ammosov, Mohammed Al Kobaisi, Yalchin Efendiev   +2 more
wiley   +1 more source

A NIR-Ⅱ-Immunostimulatory nanoplatform rewires immunometabolism to unleash STING-driven antitumor immunity. [PDF]

J Nanobiotechnology
Yang X, Chen X, Chen M, Yang S, Wu Y, Liao H, Xia T, Shen G, Sun C, Liu L.   +9 more
europepmc   +1 more source

Evaluation of precision of hydrogen isotopic composition determinations by EA-IRMS, GC-IRMS and Py-GC-IRMS

Nafta-Gaz, 2020
Marek Janiga, Małgorzata Kania
openaire   +1 more source

Collisionless Shocks: Contemporary State After Three Quarters of a Century of Research

Reviews of Geophysics, Volume 64, Issue 3, September 2026.
Abstract The collisionless shock research started in the late 1950s. Since then, plenty of data have been accumulated due to the large number of missions in the heliosphere, providing in situ measurements of the fields and particles. The quality of these measurements has vastly improved, especially in the last two decades.
M. Gedalin, M. Balikhin, V. Krasnoselskikh   +2 more
wiley   +1 more source