Lateral Composition Research Articles

Regulating Composition and Structure of Coal-based Graphene and Its Electrochemical Characteristics

Abstract Coal, a carbon-rich mineral with plentiful reserves, serves not only as a fuel but also as a raw material, presenting lower pollution emissions in the latter use. From a materials chemistry standpoint, coal is a viable raw material for graphene production. This study develops a promising and sustainable method to convert coal into graphene, leveraging its unique macromolecular aromatic structure and high carbon content. The investigation includes an analysis of the lateral size, morphology, and chemical composition of coal-derived graphene using techniques such as X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and optical microscopy. Results confirm that coal can effectively replace natural graphite flakes in graphene production, with the derived graphene featuring 3-6 exfoliated layers and an oxygen content below 5.5%. While the graphene from coal shares a similar morphology to that derived from graphite, it exhibits more structural defects. Interestingly, the macroscopic size of the coal does not influence the microscopic composition and structure of the graphene. However, the thermal reduction method for oxidized graphene proves more effective at repairing structural defects than chemical reduction. Employing coal-derived graphene as a supercapacitor electrode demonstrates excellent cycling stability and ultra-high capacitance storage capacity. The H-CG-325 shows the highest discharge area-specific capacitance across various current densities. At an increased current density of 10 A/g, the H-CG-325 maintains 80.6% of its initial capacitance of 79 F/g observed at 1 A/g. Electrochemical tests reveal that coal-based graphene holds significant potential as a supercapacitor material, indicating promising applications in energy storage and conversion.

Self-organized composite morphologies and interface instability of immiscible alloy thin films during physical vapor deposition: Insights from phase-field simulations

In this paper, we carried out phase-field simulations for investigating self-organized composite morphologies formation and interface instability of two phase immiscible binary alloy thin-film growth during physical vapor deposition. Predicted results show that for lower the deposition rate the solid-gas interface keeps planar and the lateral composition modulation (LCM) configuration occurs. As the deposition rate increases, the self-organized composite morphology gradually transfers to vertical composition modulations (VCM) configuration and the random composition modulations (RCM) configuration with the decrease of the boundary layer of the incident vapor and the unsteady solid-gas interface. Results show that the nanoprecipitate concentration modulation (NCPM) depends strongly on the nominally phase fraction. Moreover, we found that the historical dependence of self-organized composite morphologies and solid-gas interface stability, i.e., the initial condition can strongly influence the microstructure of the thin film during physical vapor deposition. Finally, we provide an analysis method for interface instability based on fast Fourier transform (FFT), and the frequency characteristics of cellular and bump structures are identified.

Reference-free x-ray fluorescence analysis with a micrometer-sized incident beam

Spatially resolved x-ray fluorescence (XRF) based analysis employing incident beam sizes in the low micrometer range (μXRF) is widely used to study lateral composition changes of various types of microstructured samples. However, up to now the quantitative analysis of such experimental datasets could only be realized employing adequate calibration or reference specimen. In this work, we extent the applicability of the so-called reference-free XRF approach to enable reference-free μXRF analysis. Here, no calibration specimen are needed in order to derive a quantitative and position sensitive composition of the sample of interest. The necessary instrumental steps to realize reference-free μXRF are explained and a validation of ref.-free μXRF against ref.-free standard XRF is performed employing laterally homogeneous samples. Finally, an application example from semiconductor research is shown, where the lateral sample features require the usage of ref.-free μXRF for quantitative analysis.

Sedimentary evolutionary processes, architecture, and sedimentary model of a lobate shallow-water delta: insights from flume simulation experiments

By using equipment such as time-lapse cameras and 3D laser scanners, this study conducted flume simulation experiments to obtain topographic elevation, the amount of sediment increment, sedimentary cross sections, and other related data and diagrams. Quantitative software was then utilized for sedimentological analysis to clarify the depositional evolution, architecture, and depositional model of lobate shallow-water deltas. The research results show that under the influence of hydraulic conditions and main distributary channels, lobate shallow-water deltas primarily undergo three evolution stages: initial channel formation, distributary channel system formation, and continuous stable evolution stage. The architecture elements of lobate shallow-water deltas can be divided into distributary channels dominated by channel deposition, proximal river mouth bars, transitional bars, and distal bars. The lateral composition and downstream deposition of the river-bar combination are the main structural units of the shallow water delta. The proximal profile distributary channels exist in the form of thick channel sand bodies with multiple repetitive intercalation cycles, and thick proximal bar deposits form on both sides of the distributary channels. The bifurcation of distributary channels in the middle profile leads to a reduction in channel scale, while large-scale proximal bars still develop on both sides of the channel. In the distal profile, a substantial river mouth bar complex is formed at the break of the delta front slope, and with the gradual progradation of the delta, the river mouth bar deposition zone becomes flattened. Based on the insights of the flume simulation experiments, a sedimentary model for lobate shallow-water delta was established.

High-pressure single-crystal elasticity of corundum: Implication for multiple seismic structure of 660-km discontinuity

The complex multi-discontinuity structure at 660‐800 km depth is likely attributable to lateral mantle composition heterogeneities, which are closely related to the mid-ocean ridge basalts (MORB). To decipher the impact of varying composition on the seismic properties of MORB, detailed knowledge of the elasticity of candidate minerals is thus important. Here we employed Brillouin scattering coupled with diamond anvil cells to determine the single-crystal elasticity of corundum up to 14 GPa and 300 K. Using third-order finite strain equation of state, we calculate the pressure derivatives of adiabatic bulk modulus and shear modulus of corundum, which yields KS0’ = 3.8(1), G0’ = 1.8(1) with KS0 = 256(1) GPa and G0 = 163(1) GPa and ρ0 = 3.987(1) g/cm3. Combined with previous high-temperature data, the velocity and anisotropy of corundum have been calculated at 300 K or along normal geotherm. Our results are applied to model the density and velocity profiles of normal and alkali-depleted MORB. Our modeling demonstrates that varying the alkali content and temperature of MORB can significantly impact the discontinuity depth and velocity jump at 660–800 km depth. For normal MORB, reducing the temperature by 300 K from normal mantle geotherm results in a shift of the velocity jump from 670–710 to 650–710 km depth but hardly affects the magnitude of the velocity jump (5.8–6.8(3)% for VP and 10.0–10.8(5)% for VS). By contrast, in alkali-depleted MORB, the discontinuity will occur at a greater depth from 705–730 to 720–745 km depending on temperature with a VP jump of 3.8–4.6(2)% and VS jump of 6.3–7.4(4)%.

Abstract 15271: Modification of Cardiomyocyte Lateral Membrane Composition Promotes Cardiac Function by Regulating Connexome Organization

Introduction: Loss of contacts between adjacent cardiomyocytes is detrimental to proper electromechanical function. For instance, connexome remodeling is a common feature of both acquired and inherited cardiac arrhythmias. We have shown that the lateral membrane-specific scaffolding protein CASK regulates the trafficking and targeting of certain connexome components, notably the sodium channel. Question: Does compartmentalization of the cardiomyocyte membrane involves lateral membrane proteins? Our hypothesis is that CASK, due to its association with costamere and its developmental expression gradient, may be involved in a more global control of connexome organization. Aims: To demonstrate that CASK, a lateral membrane-specific protein, is crucial for the development and maintenance of connexome integrity. Method: Viral constructs were designed to inhibit the expression of CASK in vivo (AAV-shCASK) and in vitro (Ad-shCASK) both in murine and human cardiomyocytes. Results: In vivo, echocardiography phenotyping of CASK invalidated rats at the neonatal stage revealed, at the adult stage, eccentric ventricular remodeling associated with increased stroke volume and increased cardiac output suggestive of athlete’s heart phenotype. Hemodynamic measurements (pressure-volume loops) confirmed that CASK invalidation increases both myocardium contractility and compliance. Proteomic analysis showed that CASK invalidation in vitro strongly modify immature cardiomyocyte proteome, notably junction signaling. Immunostaining experiments on cultured neonatal rat cardiomyocytes and adult rat hearts confirmed that CASK is required for the correct organization of myofibrils and favors connexome organization. Remarkably, CASK invalidation in a human in vitro model of arrhythmogenic cardiomyopathy (hiPSC-CM PKP2 +/- ) rescues desmosome assembly. Conclusion: CASK regulates the organization of myofibrils and connexome, with major functional consequences for cardiac performance. Our results suggest for the first time the existence of a crosstalk between lateral membrane and connexome proteins. Therefore, targeting CASK to promote electromechanical coupling of cardiomyocytes could be promising in the context of cardiac remodeling.

Analysis of polycarbonate degradation at melt/FeCr-alloy interfaces as a function of the alloy composition by means of combinatorial thin film chemistry

Interfacial reactions at the polycarbonate (PC)/FeCr-alloy interface during melt contact were studied as function of the Fe:Cr ratio within the alloy. Thin Fe/Cr films with lateral composition gradients were deposited by magnetron sputtering; the analysis of the films was done with microscopy and X-ray photoelectron spectroscopy (XPS). The local interfacial polymeric film formation could be therefore directly correlated with the Fe:Cr ratio. The local thickness and structure of the formed polycarbonate residue was analyzed by means of imaging ellipsometry, atomic force microscopy as well as Fourier-transform infrared spectroscopy under grazing incidence and XPS. Moreover, confocal fluorescence microscopy of the PC melt/alloy interface could reveal the formation of minor degradation products in the interphase region. The results show that already an Fe:Cr ratio of 2 : 1 leads to a strong inhibition of the thermal degradation in comparison to the unalloyed iron, and that in general, the enrichment of chromium in the passive film leads to an effective suppression of interfacial PC degradation. The data contributes to improving the mechanistic understanding of the role of iron during this process. Additionally, a critical concentration of chromium in the alloys used for PC processing can be deduced.

Behaviour of the Peri-Implant Soft Tissue with Different Rehabilitation Materials on Implants.

(1) Background: Mucointegration seems to gain interest when talking about success in the maintenance of dental implants. As we well know, collagen fibres cannot be inserted due to the lack of root structure on the implant surface, so the structural integration of peri-implant tissues that provide a firm seal around implants seems to be of interest when it comes to ensuring the survival of dental implants. To achieve a good epithelial barrier, the physicochemical characteristics of the surfaces of the restorative materials are of vital importance; therefore, the objective of this study is to analyse the histological behaviour of the peri-implant soft tissues in three different restorative materials. (2) Methods: Histological analysis of biopsied peri-implant keratinised mucosa, inflammatory epithelium and connective tissue in contact with a reinforced composite (BRILLIANT Crios), a cross-linked polymethylmethacrylate (TELIO CAD), and a hybrid ceramic (Vita Enamic), restored on a customised Atlantis-type abutment (Dentsply Sirona) between 60 and 180 days after restoration. (3) Results: A greater number of cells per mm2 of keratinised epithelium is observed in the reinforced composite, which could indicate greater surface roughness with greater inflammatory response. In this way, the greater number of lymphocytes and the lateral cellular composition of the inflammatory cells confirm the greater inflammatory activity towards that material. The best material to rehabilitate was hybrid ceramic, as it shows a better cellular response. (4) Conclusions: Knowing the limitations of the proposed study, despite the fact that greater inflammation is observed in the reinforced composite relative to the other materials studied, no statistically significant differences were found.

Delayed cartilage oligomeric matrix protein response to loading is associated with femoral cartilage composition post-ACLR.

To determine associations between immediate and delayed response of serum cartilage oligomeric matrix protein (sCOMP) to loading (i.e., 3000 walking steps) and femoral cartilage interlimb T1ρ relaxation times in individual's post-anterior cruciate ligament reconstruction (ACLR). This cross-sectional study included 20 individuals 6-12months following primary ACLR (65% female, 20.5 ± 4.0years old, 24.9 ± 3.0kg/m2, 7.3 ± 1.5months post-ACLR). Serum samples were collected prior to, immediately following, and 3.5h following walking 3000 steps on a treadmill at habitual walking speed. sCOMP concentrations were processed using enzyme-linked immunosorbent assays. Immediate and delayed absolute sCOMP responses to loading were evaluated immediately and 3.5h post-walking, respectively. Participants underwent bilateral magnetic resonance imaging with T1ρ sequences to calculate resting femoral cartilage interlimb T1ρ relaxation time ratios between limbs (i.e., ACLR/Uninjured limb). Linear regression models were fitted to determine associations between sCOMP response to loading and femoral cartilage T1ρ outcomes controlling for pre-loading sCOMP concentrations. Greater increases in delayed sCOMP response to loading were associated with greater lateral (∆R2 = 0.29, p = 0.02) but not medial (∆R2 < 0.01, p = 0.99) femoral cartilage interlimb T1ρ ratios. Associations between immediate sCOMP response to loading with femoral cartilage interlimb T1ρ ratios were weak and non-significant (∆R2 range = 0.02-0.09, p range = 0.21-0.58). Greater delayed sCOMP response to loading, a biomarker of cartilage breakdown, is associated with worse lateral femoral cartilage composition in the ACLR limb compared to the uninjured limb. Delayed sCOMP response to loading may be a more indicative metabolic indicator linked to deleterious changes in composition than immediate sCOMP response.

Large redshift in photoluminescence of InAs/AlAs short-period superlattices due to highly ordered lateral composition modulation

Highly ordered lateral composition modulation (LCM) is obtained in InAs/AlAs short-period superlattices (SPS) grown by molecular beam epitaxy and its effect on photoluminescence (PL) is studied. The formation of LCM and modulation length can be resolved by x-ray diffraction. Furthermore, atomic-resolution scanning transmission electron microscopy results reveal both the composition and strain distribution in the modulated and unmodulated samples and demonstrate a clear transition of strain redistribution due to LCM formation, showing that LCM is a preferential route over dislocation formation for strain relief in these strain-compensated SPSs. The LCM leads to a large redshift in PL emissions up to 0.3 eV, which we attribute to the In-rich regions in the modulated InAs/AlAs SPS. This finding facilitates a deeper understanding of these modulated SPSs.

Optimization of process parameters and mechanism of strengthening and toughening of Nb-W alloy prepared by chemical vapor deposition based on orthogonal test

In this paper, the chemical vapor deposition (CVD) method was used to prepare Nb-W binary alloys on Mo substrates for the first time. The influences of the process parameters on the composition, average deposition rate, and average deposition efficiency of the Nb-W alloys were studied by orthogonal experiments. Nb-W alloys with W contents ranging from 0.33% to 50.48% were successfully prepared. The mechanical properties and fracture morphologies of the Nb-W alloys prepared by the CVD method (CVDNb-W alloys) were tested by metallographic microscopy, scanning electron microscopy, electron probe analysis, and in situ tensile tests. The results showed that the Nb-W alloy prepared by the CVD method had uneven macroscopic distributions of Nb and W.The substrate temperature had the greatest influence on the lateral composition gradient, and the H2 flow had the least influence. The influence of the Cl2 flow through the Nb and W on the average deposition rate was also examined. The chlorination temperature of W had the least effect on the average deposition rate, and the average deposition efficiency decreased with the increase in the gaseous chloride ratio of W. The effects of other factors on the average deposition efficiency showed different degrees of wave dynamics. The metallographic observation of 16 samples showed that except for samples 3# and 4# (in which the mass percentages of W were less than 1%), the microstructures of the other samples (in which the mass percentages of W were all more than 1%) showed similar microstructures with layered structural features. Comprehensive analysis of the sample and inverse pole figures revealed that the (101) textural component mainly existed in the CVDNb-W alloys.With the increase in the mass percentage of W, the tensile strength of the CVDNb-W alloy increased correspondingly. The maximum strength of the alloy containing 9.68% W by mass reached 475 MPa, which exceeds the room-temperature tensile strength of Nb521, but the elongation at break was related to the alloy composition. Thus, the relationship did not show a discernible trend.

Masked-assisted radial-segmented target pulsed-laser deposition: A novel method for area-selective deposition using pulsed-laser deposition

We introduce a novel technique, masked-assisted radial-segmented target pulsed-laser deposition (MARS-PLD) for unprecedented capabilities in area-selective physical vapor deposition. The MARS-PLD setup consists of a conventional PLD chamber with mechanical feedthrough for a laterally movable mask or mask set. By this means and, in principle, the arbitrary choice of a shadow mask layout, any desired area on a substrate can be masked in order to create multinary lateral and vertical material composition gradients using radially segmented targets already described in the literature [Kneiß et al., ACS Comb. Sci. 20, 643–652 (2018)]. To illustrate the capabilities of this method, we fabricated material gradients in (Mg,Zn)O thin films with a nearly linear spatial variation of the cation composition of 15at.%mm−1. Additionally, we fine-tuned our setup to fabricate a material gradient on a predefined two-dimensional lateral pattern to demonstrate the versatile capabilities of the MARS-PLD technique.

Interband transitions of InAs/AlAs Short-Period superlattices grown by molecular beam epitaxy

In this work, we use spectroscopic ellipsometry (SE) to study the optical properties of InAsn/AlAsn short-period superlattices (SPS) with different period thicknesses for a wide wavelength range of 250 nm − 1650 nm (about 0.75 eV – 5 eV). Additionally, the InAs2/AlAs2 samples grown at various temperatures (450, 475, 500, 525, 550 ℃) were investigated. We extract the dielectric functions and adapt Adachi’s model to obtain the interband transition energies of E0,E0+Δ0, E1,E1+Δ1 and E2. The quantum confinement effect and the strain effect lead to the decrease of E0,E0+Δ0, E1,E1+Δ1 with the increase of period thickness. It is also found that as the growth temperature rises from 450 ℃, all the transition energies decrease as a result of the increase in the amplitude of lateral composition modulation and the relaxation of the compressive strain in InAs layers.

Material properties of gradient copper‐nickel alloy fabricated by wire arc additive manufacturing based on bypass-current PAW

In this paper, the bypass-current plasma arc welding (BC-PAW) based on PAW was employed to fabricate copper-nickel (Cu-Ni) gradient thin-walled structures. The effect of forming accuracy and compositional homogeneity of the bypass current Cu-Ni structure was first verified by controlled experiments. The effect of Ni content on the microstructure and mechanical properties of Cu-Ni gradient structures fabricated using bypass current was then investigated, with a focus on grain orientation and texture analysis of the three intermediate Cu-Ni mixed gradient layers. The results showed that the use of bypass current in the additive manufacturing of Cu-Ni gradient structures can improve the forming accuracy and effectively eliminate lateral composition deviations within the gradient layers. In the Cu-Ni mixed gradient layers, the average grain size of the gradient layers decreased with increasing nickel content, and unusually large secondary grains appeared in different gradient layers. Due to the different Ni content, different degrees of amplitude modulation decomposition occurred in different gradient layers, resulting in changes of grain orientation and texture composition. Under the combined effects of solid solution strengthening, fine grain strengthening and amplitude modulation decomposition, the microhardness and tensile strength increased with increasing nickel content and then decreased, reaching a maximum near the side of the gradient composition biased toward nickel. The fracture analysis showed a transition from ductility to quasi-fracture.

Material-Balance Method With Static Modeling Helps Generate Reliable Forecasting

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 207933, “The Integration of Analytical P/Z Material-Balance Method With Static Modeling and Integrated Asset Model To Generate Reliable Forecasting for a Giant Onshore Gas Field in Abu Dhabi,” by Bondan Bernadi, Yuni Budi Pramudyo, and Fatima Omar Alawadhi, ADNOC, et al. The paper has not been peer reviewed. Reliable field gas initially in place (FGIIP) estimation is achieved by performing multiple reservoir-pressure/gas-compressibility (P/Z) calculations. Several scenarios are developed in the complete paper by defining key areas based on permeability variation, areal distribution, and pressure/volume/temperature (PVT) behavior. The best FGIIP estimation is then fed back into the static model to generate numerous realizations considering the static uncertainties to produce the same FGIIP. A giant onshore gas field is highly heterogeneous, with permeability, lateral composition variation, and dynamic interaction between wells. Incorporating the correct estimation of FGIIP into the integrated asset model (IAM) has helped yield reliable forecasting and has enabled more-efficient field development. Introduction Reservoir A produces onshore from a limestone formation in the lower cretaceous horizon. The structure is a simple dome that is somewhat steeper on the eastern flank, with two extended noses in the south and southeast directions. The total thickness of this zone decreases down the flanks but more rapidly in the northeast direction. Formation porosity is in the range of 10 to 25%, with a permeability range of 0.5 to 88 md. The original reservoir pressure is approximately 4,300 psia, with a reservoir temperature of 260°F. The field has been producing in depletion mode for more than 30 years, flowing into one common surface network with other depletion reservoirs. More than 100 wells had been drilled in the gas-cap zone, with an average gas-production rate of 15–20 MMscf/D per well. Because of the depletion scheme applied since the beginning of field life, gas-production decline is inevitable. The focus of the complete paper mainly relates to the gas-cap zone.

Miscibility tracking in reservoirs with lateral compositional variation

Miscible gas injection is a proven enhanced oil recovery method for medium-light oils. Miscibility is typically assessed with the slimtube experiment, which aims at identifying the minimum pressure (MMP) above which the displacement process is multi-contact miscible and leads to low microscopic residual oil saturation. During implementation of a miscible gas injection scheme, there will often be areas close to producing wells where the reservoir pressure is below the MMP and the question then arises whether the process can still be considered miscible. Another complicating factor occurs in reservoirs with significant lateral fluid composition and pressure variations, where it is not intuitively clear how the MMP varies aerially.We employ 1D compositional reservoir simulation to investigate the impact of flowing bottom-hole pressures below MMP on the development and propagation of a miscible front. For systems with lateral fluid variation, we find that MMP is controlled by the reservoir fluid composition near the injection well as the injection gas will never actually contact the original fluid near the producer. We also find that a miscible displacement can be maintained even if the average reservoir pressure is slightly below MMP, as long as the local pressure at the gas-oil front exceeds MMP. Lastly, we define the minimum density difference as the overall minimum over time of the difference between oil and gas density observed at a fixed point in the system and we demonstrate that it extrapolates towards zero linearly versus pressure for the fluid systems investigated thereby enabling determination of the dispersion-free MMP with a maximum of three pressure iterations only.

Electrodeposited Ni-Fe onto Glassy Carbon for the Detection of Methylene Blue

A composite electrode composed of electrodeposited, nickel-iron nanostructured clusters onto a glassy carbon (GC) disk electrode was used as a working electrode to detect methylene blue at concentrations below 10 μM. The Ni-Fe clusters were prepared by pulse electrodeposition and a lateral composition variation was observed reflective of a local pH change across the Ni-Fe feature. The applied potential for the detection of MB at a pH of 4 was determined through voltammetry, and demonstrated using chronoamperometry and electrochemical impedance spectroscopy (EIS). The adsorption of MB influenced both the capacitance, C, and ohmic resistance, R s . A peak present in vs t chronoamperometry plots decreased with lower MB bulk concentration, while in contrast, the RsC parameters determined from equivalent circuit models of EIS had the opposite behavior having a larger signal with lower MB concentration, and hence providing a way to increase the detection signal at lower MB concentration.

Analysis of Lateral Fluid Gradients From DFA Measurements and Simulation of Reservoir Fluid Mixing Processes Over Geologic Time

Downhole fluid analysis (DFA) is one pillar of reservoir fluid geodynamics (RFG). DFA measurements provide both vertical and lateral fluid gradient data. These gradients, especially the asphaltene gradient derived from accurate optical density (OD) measurements, are critical in thermodynamic analysis to assess equilibration level and identify RFG processes. Recently, an RFG study was conducted using DFA and laboratory data from an oil field in the Norwegian North Sea. Fluid OD gradients show equilibrated asphaltenes in most of the reservoir, with a lateral variation of 20%. This indicates connectivity, which is confirmed by three years of production data. Two outliers are off the asphaltene equilibrium curve implying isolated sections, one each on the extreme east and west flank. Their asphaltene fraction varies by a factor of six. Such a difference reveals that different charge fluids entered the reservoir, and the equilibrated asphaltenes are the result of an after-charge mixing process. Meanwhile, different gas-oil contacts (GOCs) exist in the reservoir, indicating a lateral solution-gas gradient. Geochemistry analysis shows the same level of mild biodegradation in all the fluid samples, including those from two isolated sections. This means that biodegraded oil spills into the whole reservoir with little or no in-reservoir biodegradation. Furthermore, lateral asphaltene gradients at different times after charge have been preserved; it was a factor of six in asphaltenes content initially and is now 20% in the present day. This unique data set provides a valuable constraint to simulate reservoir fluid after-charge mixing processes to present day, aiming to investigate the factors impacting the evolution of lateral composition gradients in geologic time in a connected reservoir. Numerical simulations were performed over geologic time in reservoirs filled by oil with a lateral density gradient, which imitates the lateral compositional gradients in the gas-oil ratio (GOR) and asphaltenes measured in the above oil field. Simulations show that this lateral gradient creates lateral differential pressures and causes a countercurrent fluid flow forming a convection cell. In reservoirs with realistic vertical-to-horizontal aspect ratios, such fluid flows are not rapid, and lateral gradients can be partially retained in moderate geologic times. Additionally, diffusion was included in the simulation. The reservoir model was initialized with two GOCs producing subtle lateral GOR and density gradients. The simulated mixing process transports gas from higher GOR regions to lower GOR regions and reduces the GOC difference. However, the flux of solution gas transport is small. Consequently, we conclude that lateral GOR and asphaltene gradients can persist for moderate geologic time, which is consistent with observation from the field.

Molecular and biophysical mechanisms behind the enhancement of lung surfactant function during controlled therapeutic hypothermia

Therapeutic hypothermia (TH) enhances pulmonary surfactant performance in vivo by molecular mechanisms still unknown. Here, the interfacial structure and the composition of lung surfactant films have been analysed in vitro under TH as well as the molecular basis of its improved performance both under physiological and inhibitory conditions. The biophysical activity of a purified porcine surfactant was tested under slow and breathing-like dynamics by constrained drop surfactometry (CDS) and in the captive bubble surfactometer (CBS) at both 33 and 37 °C. Additionally, the temperature-dependent surfactant activity was also analysed upon inhibition by plasma and subsequent restoration by further surfactant supplementation. Interfacial performance was correlated with lateral structure and lipid composition of films made of native surfactant. Lipid/protein mixtures designed as models to mimic different surfactant contexts were also studied. The capability of surfactant to drastically reduce surface tension was enhanced at 33 °C. Larger DPPC-enriched domains and lower percentages of less active lipids were detected in surfactant films exposed to TH-like conditions. Surfactant resistance to plasma inhibition was boosted and restoration therapies were more effective at 33 °C. This may explain the improved respiratory outcomes observed in cooled patients with acute respiratory distress syndrome and opens new opportunities in the treatment of acute lung injury.

Indium Gallium Oxide Alloys: Electronic Structure, Optical Gap, Surface Space Charge, and Chemical Trends within Common-Cation Semiconductors.

The electronic and optical properties of (InxGa1-x)2O3 alloys are highly tunable, giving rise to a myriad of applications including transparent conductors, transparent electronics, and solar-blind ultraviolet photodetectors. Here, we investigate these properties for a high quality pulsed laser deposited film which possesses a lateral cation composition gradient (0.01 ≤ x ≤ 0.82) and three crystallographic phases (monoclinic, hexagonal, and bixbyite). The optical gaps over this composition range are determined, and only a weak optical gap bowing is found (b = 0.36 eV). The valence band edge evolution along with the change in the fundamental band gap over the composition gradient enables the surface space-charge properties to be probed. This is an important property when considering metal contact formation and heterojunctions for devices. A transition from surface electron accumulation to depletion occurs at x ∼ 0.35 as the film goes from the bixbyite In2O3 phase to the monoclinic β-Ga2O3 phase. The electronic structure of the different phases is investigated by using density functional theory calculations and compared to the valence band X-ray photoemission spectra. Finally, the properties of these alloys, such as the n-type dopability of In2O3 and use of Ga2O3 as a solar-blind UV detector, are understood with respect to other common-cation compound semiconductors in terms of simple chemical trends of the band edge positions and the hydrostatic volume deformation potential.