Relevant Temperature Conditions Research Articles

Comparative Inactivation of the RNA of the Delta and Omicron Variants of SARS-CoV-2 in Wastewater of Five Municipalities in Southeast Germany

During the COVID-19 pandemic, wastewater-based epidemiology has been extensively used as a helpful tool for evaluation of the epidemic situation in catchments of wastewater treatment plants. In this context, knowledge about the rate of virus inactivation in wastewater is important for characterization of the influence of retention times in sewers on virus concentrations, of the storage periods before analysis in the laboratory, on virus elimination during treatment and for modeling approaches. In the present study, we genotyped SARS-CoV-2 in the respiratory tract specimens of infected patients and spiked the raw wastewater of five treatment plants with aliquots of these samples. The test preparations were incubated under practically relevant temperature conditions (14 °C) over 31 days. The linear decay rates resulted in comparable T90 values (30.5 d) for the Delta and the Omicron BA1 variants of SARS-CoV-2 without differences in using the E or S gene of the virus as the target for amplification. In contrast, the origin of wastewater influenced the inactivation rate of both variants significantly, with the mean T90 values varying between 24.3 and 53.1 days in the wastewater from the five plants. The data suggest that the inactivation rate of SARS-CoV-2 in wastewater is more strongly determined by the composition of the water than by the virus variant.

Extending damage accumulation of commercial reactor irradiated 316 stainless steel with ion irradiation

Austenitic 316 stainless steel flux thimble tubes (FTTs) removed from a commercial pressurized water reactor (PWR) were re-irradiated using nickel ions to evolve the irradiated microstructure to higher damage levels than those achieved in reactor. The microstructures of the neutron-plus-ion irradiated samples were compared with those of neutron irradiated only samples at the same doses to evaluate the effectiveness of ion irradiation to extend the damage range and match that created in reactor. Ion irradiations effectively captured, both qualitatively and semi-quantitatively, the evolution of dislocation loops, nanocavities, nanocluster size and density, and radiation-induced segregation (RIS) with dose. Only Ni-Si clusters were observed in ion irradiated FTT samples while Ni-Si-Mn clusters that were frequently observed in reactor irradiated samples above ∼41 dpa were absent in ion irradiated samples probably due to ballistic mixing at the high ion irradiation damage rate. Two samples were ion irradiated to ∼160 dpa to predict the irradiated microstructure that may develop due to an increase of the damage accumulation by extending a PWR life from 40 years to 60 years. The extended ion irradiation results indicated that significant microstructure changes were unlikely to occur even to very high doses near common PWR relevant temperature conditions. Overall, the microstructure resulting from ion irradiation following neutron irradiation matched that of neutron to the same dose reasonably well in most cases.

Acetylene storage performance of [Ni(4,4′-bipyridine)2(NCS)2]n, a switching square lattice coordination network

The coordination network sql-1-Ni-NCS exhibits benchmark working capacity for acetylene storage at practically relevant conditions of temperature and pressure.

Analysis of ignition temperature range and surrogate fuel requirements for GCI engine

Gasoline compression ignition (GCI) technology aims to improve internal combustion engine (ICE) efficiency. However, much is still unknown about the detailed combustion behavior of fuels under this novel ICE technology, such as relevant ignition temperature regimes and surrogate requirements under various engine load and speed conditions as well as for different fuels. Engine and spray simulations require the use of carefully designed surrogate fuels that mimic the properties of real fuels. Generally, these surrogates range from simple primary reference fuels (PRFs) to complex multi-component mixtures. This study aims to identify the relevant temperature conditions and the surrogate requirements for GCI engines covering the entire engine speed-load map; engine loads between 1 and 22 bar indicated mean effective pressure (IMEP) and engine speeds between 800 and 2500 revolutions per minute (RPM). Simulations were performed using the constant volume zero-dimensional (0-D) and homogeneous charge compression ignition (HCCI) modules in Chemkin-Pro for two gasoline fuels with widely different sensitivities (11 and 0). Furthermore, homogeneous ignition delay times and Livengood-Wu integrals were used to analyze the fundamental characteristics of GCI combustion. It was found that, except at excessively high-load, the relevant ignition temperature in a GCI engine is in the 750–1000 K range. The low-temperature (less than700 K) reactivity exhibited negligible contribution to the ignition of the high-sensitivity fuel. Two stage ignition and cool flame formation were found to dominate mid-load kinetics of the low-sensitivity fuel. Simple PRF surrogate was found to be sufficient to mimic the ignition requirement of the low-sensitivity gasoline fuel at almost the entire GCI engine speed-load map. However, for the high-sensitivity gasoline fuel, TPRF and TPRFE surrogates were needed for a better representation of the auto-ignition behavior. The obtained knowledge of the surrogate requirement and the ignition temperature regimes inside GCI engine will aid in guiding GCI engine optimization and fuel design.

Asymmetric glycerophospholipids impart distinctive biophysical properties to lipid bilayers

Phospholipids are a diverse group of biomolecules consisting of a hydrophilic headgroup and two hydrophobic acyl tails. The nature of the head and length and saturation of the acyl tails are important for defining the biophysical properties of lipid bilayers. It has recently been shown that the membranes of certain yeast species contain high levels of unusual asymmetric phospholipids consisting of one long and one medium-chain acyl moiety, a configuration not common in mammalian cells or other well-studied model yeast species. This raises the possibility that structurally asymmetric glycerophospholipids impart distinctive biophysical properties to the yeast membranes. Previously, it has been shown that lipids with asymmetric length tails form a mixed interdigitated gel phase and exhibit unusual endotherm behavior upon heating and cooling. Here, however, we address physiologically relevant temperature conditions and, using atomistic molecular dynamics simulations and environmentally sensitive fluorescent membrane probes, characterize key biophysical parameters (such as lipid packing, diffusion coefficient, membrane thickness, and area per lipid) in membranes composed of both length-asymmetric glycerophospholipids and ergosterol. Interestingly, we show that saturated but asymmetric glycerophospholipids maintain membrane lipid order across a wide range of temperatures. We also show that these asymmetric lipids can substiture of unsaturated symmetric lipids in the phase behaviour of ternary lipid bilayers. This may allow cells to maintain membrane fluidity, even in environments that lack oxygen, which is required for the synthesis of unsaturated lipids and sterols.

Contribution of Temperature Increase to Restrain the Transmission of COVID-19

SummaryThe COVID-19 outbreak has already become a global pandemic and containing this rapid worldwide transmission is of great challenge. The impacts of temperature and humidity on the COVID-19 transmission rate are still under discussion. Here, we elucidated these relationships by utilizing two unique scenarios, repeated measurement and natural experiment, using the COVID-19 cases reported from January 23 – February 21, 2020, in China. The modeling results revealed that higher temperature was most strongly associated with decreased COVID-19 transmission at a lag time of 8 days. Relative humidity (RH) appeared to have only a slight effect. These findings were verified by assessing SARS-CoV-2 infectivity under the relevant conditions of temperature (4°C–37°C) and RH (> 40%). We concluded that temperature increase made an important, but not determined, contribution to restrain the COVID-19 outbreak in China. It suggests that the emphasis of other effective controlling polices should be strictly implemented to restrain COVID-19 transmission in cold seasons.

Polyacrylamide's function on increasing salinity in shale gas wastewater production

Large volumes of water containing friction-reducing additives are injected into target rock formations during hydraulic fracturing in shale gas production. The interactions between the fracking fluids and the reservoir rocks may increase the flowback and produced (FP) salinity, rendering the fluid ineffective for reuse and recycling. To explore the function of polyacrylamide (PAM; a widely applied friction-reducing additive) on the evolution of FP water salinity, three fluid-rock interaction experiments were conducted under relevant temperature conditions. Sr concentrations and 87Sr/86Sr were measured to identify mineral exchanges. Results showed that the dominant geochemical reactions were pyrite oxidation, carbonate, and silicate mineral dissolution, and halite dissolution; the hydrolysis of polyacrylamide facilitated mineral dissolution. Another one-tenth of carbonate was mobilized and the total oxidized pyrite mass was nearly 30 times greater on the function of PAM. These findings imply that the development of brine-tolerant polyacrylamide is necessary to effectively reuse and recycle FP water. This is beneficial for the environment as this minimizes the dependency on freshwater supplies. This study provides new information on the interactions between the fracturing fluid and the reservoir rocks and further elucidates the influence of polyacrylamide on wastewater salinity.

Autophagy and Heat Shock Responses in Human Peripheral Blood Mononuclear Cells During Physiologically Relevant Heat Stress Conditions

When exposed to stress caused by elevated internal body temperatures, proteins become denatured or misfolded, leading to toxic protein aggregation. To protect the cell under heat stress, misfolded proteins are tagged or refolded by heat shock proteins (HSP). Under conditions of extreme heat stress, the process of autophagy has previously been shown to protect human cells, but the exact temperatures at which autophagic activation occurs is largely unknown. Further, the interplay of HSP and autophagy responses as a function of increasing levels of hyperthermia have yet to be examined. Thus, the purpose of this study was to examine threshold changes in the autophagy and heat shock response to increasing levels of in vitro heat stress characteristic to physiologically relevant temperature conditions representative of normal (37°C), moderate (39°C), and severe (41°C) heat stress conditions in humans. We hypothesized that autophagy and HSP responses in human peripheral blood mononuclear cells (PBMCs) would increase in a dose‐dependent manner to heat stress in young adults. To test our hypothesis, whole blood was collected from 20 young (23±4 years; 10 women) participants. PBMCs were isolated immediately (baseline) and after 90‐min of whole‐blood heating in 37, 39, and 41°C water baths. Using western blot and qRT‐PCR techniques, the interplay of autophagy and HSP was characterized through measurements of microtubule associated protein 1 light chain 3 beta (LC3B), p62/sequesterome‐1 (p62), and heat shock protein 70 (HSP70) proteins and their associated genes. All values are reported as fold‐change relative to baseline values after being normalized to β‐actin. Statistical analysis was completed using a one‐way repeated measures ANOVA to asses fold change in proteins and genes between each heat condition. In the simulated thermoneutral conditions of 37°C, increased autophagic activity was demonstrated only through decreased levels of p62 protein (0.73±0.40, p<0.01) but no significant changes (p>0.05) in protein synthesis and gene expression in HSP70 (1.11±0.29) or LC3B (0.87±0.34) were observed. Subsequently, responses of HSP and autophagy increased at moderate heat stress (39°C) with increased p62 (2.31±2.02, p<0.01) and LC3B gene expression (1.86±1.21, p<0.01), an increased protein response in HSP70 (1.19±0.37, p=0.03), a decreased protein response in p62 (0.66±0.29, p<0.01), and no significant protein response in LC3B (1.04±0.24, p>0.05). At the highest level of heat stress (41°C), increases in protein synthesis and gene expression were observed in HSP70 (1.38±0.49, 2.77±2.15 respectively; all p<0.01) and LC3B (1.39±0.57, 2.32±1.80 respectively; all p<0.01) concomitant with decreased p62 protein synthesis (0.73±0.28, p<0.01) indicating an increase in the HSP response and autophagic flux. Taken together, our findings demonstrate that in human PBMCs, the HSP and autophagy systems work synergistically in responding to increases in the level of heat stress occurring within the human system.Support or Funding InformationCanadian Institutes of Health Research

The effect of curing temperature on autogenous deformation of fly ash concretes

For concrete subjected to restrained conditions, autogenous deformation (AD) and thermal dilation (TD) are the main driving forces behind stress development in the hardening phase. Generally, AD in concrete is modelled by model codes or measured in the laboratory under 20 °C isothermal conditions, and then used as basis for stress calculations under realistic temperature conditions. To evaluate this common simplification, the current study investigated the effect of curing temperature on the AD of a series of fly ash concretes. A comprehensive test program was performed for fly ash concretes subjected to various temperature curing conditions. The model codes and measurements under 20 °C isothermal conditions provided AD developments in the same order of magnitude. However, when subjected to a realistic temperature history during curing, major changes in the AD developments were observed, emphasising that AD must be determined under relevant temperature conditions.

Optimal efficiency of the Q-cycle mechanism around physiological temperatures from an open quantum systems approach

The Q-cycle mechanism entering the electron and proton transport chain in oxygenic photosynthesis is an example of how biological processes can be efficiently investigated with elementary microscopic models. Here we address the problem of energy transport across the cellular membrane from an open quantum system theoretical perspective. We model the cytochrome {b}_{6},f protein complex under cyclic electron flow conditions starting from a simplified kinetic model, which is hereby revisited in terms of a Markovian quantum master equation formulation and spin-boson Hamiltonian treatment. We apply this model to theoretically demonstrate an optimal thermodynamic efficiency of the Q-cycle around ambient and physiologically relevant temperature conditions. Furthermore, we determine the quantum yield of this complex biochemical process after setting the electrochemical potentials to values well established in the literature. The present work suggests that the theory of quantum open systems can successfully push forward our theoretical understanding of complex biological systems working close to the quantum/classical boundary.

Experimental Investigation of Bi-2223/Ag Superconducting Tape Joints

We have developed a manufacturing method for superconducting joints for Bi-2223/Ag tapes (DI-BSCCO Type-H, Sumitomo Electric Industries Ltd., Yokosuka, Japan). The tapes' superconducting joints were fabricated under pressure and heat treatment processes. The critical currents of these joints under relevant temperature conditions were measured to investigate their applicability to superconducting devices such as magnetic shields and superconducting magnets using current transport tests. In addition, the critical currents were investigated in a parallel magnetic field to the tape surface up to 5 T at 4 and 20 K. We will report the results of these experiments.

High-Throughput In-Use and Stress Size Stability Screening of Protein Therapeutics Using Algorithm-Driven Dynamic Light Scattering

Stability of therapeutic proteins (TPs) is a critical quality attribute that impacts both safety and efficacy of the drug. Size stability is routinely performed during and after biomanufacturing. Dynamic light scattering (DLS) is a commonly used technique to characterize hydrodynamic size of the TPs. Herein, we have developed a novel method to evaluate in-use and thermal stress stability of TPs using algorithm-driven high-throughput DLS. Five marketed TPs were tested under the guidance of customized algorithms. The TPs were evaluated at relevant temperature conditions as well as under dilution and thermal stress for size stability. We found that the TPs were stable under the in-use conditions tested; however, sample loss due to evaporation can lead to large protein aggregates. A combined assessment of autocorrelation function and photos of sample well could be useful in formulation screening. Dilution of TPs also has an impact on the hydrodynamic size. Thermal stress experiments showed the importance of using different data processing methods to access size distribution. Polydispersity index was useful in evaluating sample heterogeneity. Herein, we show that algorithm-driven high-throughput DLS can provide additional supportive information during and after biomanufacturing and the potential to be used in a quality control environment.

A numerical procedure enabling accurate descriptions of strain rate-sensitive flow of polycrystals within crystal visco-plasticity theory

The plastic deformation of polycrystalline metals is carried by the motion of dislocations on specific crystallographic glide planes. According to the thermodynamics theory of slip, in the regime of strain rates, roughly from 10−5/s to 105/s, dislocation motion is thermally activated. Dislocations must overcome barriers in order to move, and this concept defines critical activation stresses τcs on a slip system s that evolve as a function of strain rate and temperature. The fundamental flow rule in crystal visco-plasticity theory that involves τcs in order to activate slip has a power-law form: γ̇s=γ̇0(|τs|τcs)nsign(τs). This form is desirable because it provides uniqueness of solution for the active slip systems that accommodate an imposed strain rate; however, it also introduces a strain rate dependence, which in order to represent the actual behavior of polycrystalline materials deforming in relevant conditions of temperature and strain-rate usually needs to be described by a high value of the exponent n. However, since until now the highest value of n was limited by numerical tractability, the use of the power-law flow rule frequently introduced an artificially high rate-sensitivity. All prior efforts to correct this extraneous rate sensitivity have only lessened its effect and unfortunately also at the expense of substantial increases in computation time. To this day, a solution for the power-law exponent reflecting true material behavior is still sought. This article provides a novel method enabling the use of realistic material strain rate-sensitivity exponents to be used within the crystal visco-plasticity theory without increasing computation time involved in polycrystal simulations. Calculations are performed for polycrystalline pure Cu and excellent agreement with experimental measurement is demonstrated.

Ice nucleation activity of diesel soot particles at cirrus relevant temperature conditions: Effects of hydration, secondary organics coating, soot morphology, and coagulation

AbstractIce formation by diesel soot particles was investigated at temperatures ranging from −40 to −50°C. Size‐selected soot particles were physically and chemically aged in an environmental chamber, and their ice nucleating properties were determined using a continuous flow diffusion type ice nucleation chamber. Bare (freshly formed), hydrated, and compacted soot particles, as well as α‐pinene secondary organic aerosol (SOA)‐coated soot particles at high relative humidity conditions, showed ice formation activity at subsaturation conditions with respect to water but below the homogeneous freezing threshold conditions. However, SOA‐coated soot particles at dry conditions were observed to freeze at homogeneous freezing threshold conditions. Overall, our results suggest that heterogeneous ice nucleation activity of freshly emitted diesel soot particles are sensitive to some of the aging processes that soot can undergo in the atmosphere.

The Environmental Photochemistry of Oxide Surfaces and the Nature of Frozen Salt Solutions: A New in Situ XPS Approach

Recent years have witnessed fast advancements in near ambient pressure X-ray photoelectron (NAPP) spectroscopy, which is emerging as a powerful tool for the investigation of surfaces in presence of vapors and liquids. In this paper we present a new chamber for the investigation of solid/vapor interfaces relevant to environmental and atmospheric chemistry that fits to the NAPP endstation at the Swiss Light Source. The new chamber allows for performing X-ray photoelectron spectroscopy (XPS) and electron yield near-edge X-ray absorption fine structure spectroscopy (NEXAFS) using soft, tender and hard X-ray in vacuum and in near-ambient pressures up to 20 mbar at environmentally relevant conditions of temperature and relative humidity. In addition, the flow tube design of the chamber enables the dosing of sticky reactive gases with short pressure equilibration time. The accessible photoelectron kinetic energy ranges from 2 to 7000 eV. This range allows the determination of surface and bulk electronic properties of ice and other environmental materials, such as metal oxides and frozen solutions, which are relevant to understanding atmospheric chemistry. The design of this instrument and first results on systems of great interest to the environmental and atmospheric chemistry community are presented. In particular, near-ambient pressure XPS and NEXAFS, coupled to a UV-laser setup, were used to study the adsorption of water on a TiO2 powder sample. The results are in line with previously proposed adsorption models of water on TiO2, and, furthermore, indicate that the concentration of water molecules tends to increase upon UV irradiation. In a second example we illustrate how NEXAFS spectroscopy measurements at the chlorine K-edge can provide new insight on the structures of eutectic and sub-eutectic frozen NaCl solutions at high and low relative humidity, respectively, indicating the formation of solution and solid NaCl phases, respectively. Finally, we demonstrate the assets of this new chamber for the dosing of sticky acidic gases and, in particular, for the investigation of formic acid uptake on ice surfaces.

Promoter effect of hydration on the nucleation of nanoparticles: direct observation for gold and copper on rutile TiO2 (110).

Direct observation of the promoting effect of hydration on the nucleation of gold and copper nanoparticles supported on partially reduced rutile TiO2 (110) is achieved by combined scanning tunneling microscopy experiments and density functional theory calculations. The experiments show a clear difference between the two metals. Gold nanoparticles grow at the vicinity of the surface hydroxyl domains, whereas the nucleation of copper is not substantially affected by hydration. The nucleation of gold on surface oxygen vacancies is observed although this is not the only preferential site. Theoretical calculations of the coadsorbed phases of gold, copper and hydroxyl species on stoichiometric and reduced TiO2 (110) surfaces under relevant conditions of temperature and pressure support the experimental interpretation. Surface hydration tends to stabilize significantly gold adsorption on the stoichiometric support, while its influence on copper adsorption is not pronounced. The theoretical analysis shows that the early stages of the nucleation on hydrated stoichiometric surfaces correspond to mono-hydroxylated metallic species co-chemisorbed with hydroxyl species, whereas those on hydrated reduced surfaces are metallic atoms bound to oxygen vacancies and weakly perturbed by surface hydration.

Numerical analysis of modified Central Solenoid insert design

The United States ITER Project Office (USIPO) is responsible for fabrication of the Central Solenoid (CS) for ITER project. The ITER machine is currently under construction by seven parties in Cadarache, France. The CS Insert (CSI) project should provide a verification of the conductor performance in relevant conditions of temperature, field, currents and mechanical strain. The US IPO designed the CSI that will be tested at the Central Solenoid Model Coil (CSMC) Test Facility at JAEA, Naka. To validate the modified design three-dimensional numerical simulations were performed using coupled solver for simultaneous structural, thermal and electromagnetic analysis. Thermal and electromagnetic simulations supported structural calculations providing necessary loads and strains. According to current analysis design of the modified coil satisfies ITER magnet structural design criteria for the following conditions: (1) room temperature, no current, (2) temperature 4K, no current, (3) temperature 4K, current 60kA direct charge, and (4) temperature 4K, current 60kA reverse charge. Fatigue life assessment analysis is performed for the alternating conditions of: temperature 4K, no current, and temperature 4K, current 45kA direct charge. Results of fatigue analysis show that parts of the coil assembly can be qualified for up to 1 million cycles. Distributions of the Current Sharing Temperature (TCS) in the superconductor were obtained from numerical results using parameterization of the critical surface in the form similar to that proposed for ITER. Special ADPL scripts were developed for ANSYS allowing one-dimensional representation of TCS along the cable, as well as three-dimensional fields of TCS in superconductor material.

Optimization of ITER Central Solenoid Insert design

The United States ITER Project Office (USIPO) is responsible for fabrication of the Central Solenoid (CS) for International Thermonuclear Experimental Reactor (ITER). The CS Insert (CSI) project should provide a verification of the conductor performance in relevant conditions of temperature, field, currents and mechanical strain. The US IPO will build the CSI that will be tested at the Central Solenoid Model Coil (CSMC) Test Facility at JAEA, Naka. One of the design goals of the CSI is to assure that the properties of the conductor near the median plane are measured accurately. Since Nb3Sn is strain sensitive and electromagnetic forces generate a significant strain that increases the current sharing temperature (Tcs), we need to design the Insert in such a way that the most strained conductor near the median plane would still have the lowest Tcs of all the rest of the conductor in the Insert. The difference between thermal contraction of the jacket and spacer material allows controlling axial distribution of the coil radial deformation. Numerical analysis of the CSI was performed using stainless steel, titanium and invar spacer material variants. Distribution of the Tcs was obtained from numerical results in the form similar to one proposed for ITER.

Local temperatures inferred from plant communities suggest strong spatial buffering of climate warming across Northern Europe

Recent studies from mountainous areas of small spatial extent (<2500 km(2) ) suggest that fine-grained thermal variability over tens or hundreds of metres exceeds much of the climate warming expected for the coming decades. Such variability in temperature provides buffering to mitigate climate-change impacts. Is this local spatial buffering restricted to topographically complex terrains? To answer this, we here study fine-grained thermal variability across a 2500-km wide latitudinal gradient in Northern Europe encompassing a large array of topographic complexities. We first combined plant community data, Ellenberg temperature indicator values, locally measured temperatures (LmT) and globally interpolated temperatures (GiT) in a modelling framework to infer biologically relevant temperature conditions from plant assemblages within <1000-m(2) units (community-inferred temperatures: CiT). We then assessed: (1) CiT range (thermal variability) within 1-km(2) units; (2) the relationship between CiT range and topographically and geographically derived predictors at 1-km resolution; and (3) whether spatial turnover in CiT is greater than spatial turnover in GiT within 100-km(2) units. Ellenberg temperature indicator values in combination with plant assemblages explained 46-72% of variation in LmT and 92-96% of variation in GiT during the growing season (June, July, August). Growing-season CiT range within 1-km(2) units peaked at 60-65°N and increased with terrain roughness, averaging 1.97 °C (SD = 0.84 °C) and 2.68 °C (SD = 1.26 °C) within the flattest and roughest units respectively. Complex interactions between topography-related variables and latitude explained 35% of variation in growing-season CiT range when accounting for sampling effort and residual spatial autocorrelation. Spatial turnover in growing-season CiT within 100-km(2) units was, on average, 1.8 times greater (0.32 °C km(-1) ) than spatial turnover in growing-season GiT (0.18 °C km(-1) ). We conclude that thermal variability within 1-km(2) units strongly increases local spatial buffering of future climate warming across Northern Europe, even in the flattest terrains.

Resolving kinetics and dynamics of a catalytic reaction inside a fixed bed reactor by combined kinetic and spectroscopic profiling

The oxidative dehydrogenation of ethane to ethylene was studied using a MoO3 based catalyst supported on γ-alumina spheres. The measurement of species and temperature profiles through a fixed bed reactor shows for the first time the reaction pathways inside the catalyst bed directly. Oxidative dehydrogenation of ethane to ethylene and water occurs on the redox sites of MoO3 only in the presence of gas phase oxygen. Further oxidation of the product ethylene to carbon dioxide occurs as a subsequent reaction step by lattice oxygen of MoO3. Deep oxidation of ethylene to CO2 is the only existing reaction in the absence of gas phase oxygen reducing MoO3 to MoO2. Oxidation of CO and C2H6 by lattice oxygen does not occur. The reduction of the catalyst can be followed by in situ fiber Raman spectroscopy as a function of the oxygen partial pressure. The in situ Raman measurements are complemented by ex situ micro-Raman spectroscopy and X-ray diffraction. The combined measurement of kinetic and spectroscopic reactor profiles presents a novel approach in in situ catalysis research to establish catalyst structure–function relationships under technically relevant conditions of temperature and pressure.