Values Of ΔF Research Articles

In-vitro and in-vivo comparative studies of treatment effects on enamel demineralization during orthodontic therapy: implications for clinical early-intervention strategy

ObjectivesThis study aimed to investigate if CPP-ACP / infiltrating resin was superior in treating enamel demineralization during orthodontic therapy compared with fluoride varnish, in order to provide early-intervention implications for dental professionals.Materials and methodsIn the in-vitro study, premolars were grouped into four: remineralization with fluoride varnish / CPP-ACP, sealing with infiltrating resin, and negative control. Experimental demineralization of enamel surfaces was analyzed using techniques of QLF, SEM, EDS and micro-hardness testing. An in-vivo intervention study was conducted on patients randomly assigned into three groups. At the baseline and every-3-month follow-up, QLF parameters were compared temporally and parallelly to yield potential implications for promotion in clinical practice.ResultsThe in-vitro study performed on 48 experimental tooth surfaces demonstrated that sealing with infiltrating resin reduced enamel surface porosity and increased surface micro-hardness significantly. In the in-vivo intervention study on 163 tooth surfaces, it was suggested that for those who meet the criteria of -10 < ΔF < -6 and − 1000 < ΔQ < -20 at the baseline, all these treatment methods could achieve acceptable outcomes; with the rising of absolute values of ΔF and ΔQ, sealing with infiltrating resin showed more evident advantages.ConclusionFor enamel demineralization during orthodontic therapy, all the treatment methods involved in this study showed acceptable effectiveness but had respective characteristics in treatment effects. QLF parameters could be used as indicators for clinical early-intervention strategy with regards to this clinical issue.Clinical relevanceWith QLF parameters, clinical early-intervention strategy for enamel demineralization during orthodontic therapy could be optimized.

The Role of Lipid Intrinsic Curvature in the Droplet Interface Bilayer.

Model bilayers are constructed from lipids having different intrinsic curvatures using the droplet interface bilayer (DIB) method, and their static physicochemical properties are determined. Geometrical and tensiometric measurements are used to derive the free energy of formation (ΔF) of a two-droplet DIB relative to a pair of isolated aqueous droplets, each decorated with a phospholipid monolayer. The lipid molecules employed have different headgroup sizes but identical hydrophobic tail structure, and each is characterized by an intrinsic curvature value (c0) that increases in absolute value with decreasing size of headgroup. Mixtures of lipids at different ratios were also investigated. The role of curvature stress on the values of ΔF of the respective lipid bilayers in these model membranes is discussed and is illuminated by the observation of a decrement in ΔF that scales as a near linear function of c02. Overall, the results reveal an association that should prove useful in studies of ion channels and other membrane proteins embedded in model droplet bilayer systems that will impact the understanding of protein function in cellular membranes composed of lipids of high and low curvature.

Stiffness of Contacts between Adsorbed Particles and the Surface of a QCM‐D Inferred from the Adsorption Kinetics and a Frequency‐Domain Lattice Boltzmann Simulation

AbstractA simulation based on the frequency‐domain lattice Boltzmann method (FreqD‐LBM) is employed to predict the shifts of resonance frequency, Δf, and half bandwidth, ΔΓ, of a quartz crystal microbalance with dissipation monitoring (QCM‐D) induced by the adsorption of rigid spheres to the resonator surface. The comparison with the experimental values of Δf and ΔΓ allows to estimate the stiffness of the contacts between the spheres and the resonator surface. The contact stiffness is of interest in contact mechanics, but also in sensing because it depends on the properties of thin films situated between the resonator surface and the sphere. The simulation differs from previous implementations of FreqD‐LBM insofar, as the material inside the particles is not included in the FreqD‐LBM algorithm. Rather, the particle surface is configured to be an oscillating boundary. The amplitude of the particles' motions (displacement and rotation) is governed by the force balance at the surface of the particle. Because the contact stiffness enters this balance, it can be derived from experimental values of Δf and ΔΓ. The simulation reproduces experiments by the Krakow group. For sufficiently small spheres, a contact stiffness can be derived from the comparison of the simulation with the experiment.

Physical reasons for regular discrepancies in values of the PCN and PCS indices characterizing magnetic activity in the northern and southern polar caps

PC index characterizes magnetic activity generated in polar caps by R1 FAC system related to the solar wind electric field EKL. The PC index is calculated separately by data on magnetic disturbance values δF at stations Thule (PCN) and Vostok (PCS) with use of the “unified PC derivation method” taking into account statistically justified relationships between values of EKL and δF at these stations. Nevertheless, discrepancy between PCN and PCS indices is regularly observed: the value of difference ΔPC = PCN-PCS demonstrates the obvious seasonal variation and strongly increases in periods of high magnetic activity, the ΔPC values being the highest (>1 mV/m) in epochs of solar activity maximum and being the lowest (<0.5 mV/m) in the quiet periods. Analysis of discrepancies ΔPC, carried out by data on the 1-min definitive PCN and PCS indices for 22 year (1997–2022), showed that difference between the daily PCN and PCS values is caused by influence of the azimuthal BY IMF component, which generates the specific BY FAC system with reverse polarity of field-aligned currents in the northern and southern hemispheres. Effect of these currents, which is opposite in northern and southern polar caps, critically distorts the regular ionospheric current systems related to EKL field influence, resulting in discrepancy of corresponding PCN and PCS indices.

Biodegradable Lubricant with High-Temperature and Ionic-Contamination Resistance: Deep Eutectic Solvent ChCl-PEG.

Drilling fluid lubricants guarantee safe and fast drilling. When drilling high-temperature or NaCl/CaCl2-containing formations, there is an urgent need to develop environmentally friendly lubricants that are resistant to high temperature and ionic contamination. In this study, a deep eutectic solvent (DES) ChCl-PEG lubricant for a water-based drilling fluid was designed and prepared. ChCl-PEG is a kind of biodegradable material with high thermal stability formed by hydrogen bonding between choline chloride (ChCl) and polyethylene glycol (PEG). Within 240 °C, ChCl-PEG significantly improved the lubricating properties of drilling fluids and mud cakes. The lubrication coefficient (K) was controlled within 0.2, and the reduction rate of the adhesion coefficient (Δf) was higher than 40%. The salt and calcium resistances of ChCl-PEG at high temperature (150 °C) are as high as 36% NaCl and 20% CaCl2. Under these conditions, ChCl-PEG maintains a low value of K: 0.097-0.157 (5-36% NaCl) and 0.145-0.162 (5-20% CaCl2), respectively. Also, it maintains higher values of Δf, which can reach up to 51.6% and 80%. The lubricating mechanism of ChCl-PEG can be summarized as the adsorption of ChCl and the formation of a large number of hydrated molecules.

Multifractal approach to gully network interpretation of an alluvial badland terrain

Badlands are intensely gullied lands, undergoing heavy soil losses, bereft of sustainability and are degenerative to the verdant ecosystem. This paper aims at using multifractal and lacunarity analysis to badlands systems, with the objective of offering geomorphic correlation and interpretation of multifractal parameters to understand the nature of patterns and the operative processes in badlands. Interpretability of the parameters, namely generalised dimension (Dq) versus exponent (Q), multifractal function of the component (f(α)) versus Holder’s exponent (α), (Δα), Δf (α) and lacunarity (Ʌ or λ), provides an efficient approach to comprehend and resolve the dynamic problem of badlands patterns. Four badlands sites were selected in the study area and the analysis was done using ImageJ software. The analysis showed that the sigmoidal curves of Dq versus Q decreasing towards higher values of Q (Q > 0) and the high values of Dq indicate that the badlands are typical multifractal patterns and have been densely dissected. The graphs of f(α) versus (α) are hump-shaped and are right-skewed with negative values of Δf (α), which suggests that erosion processes are active on a finer scale in the area. The greater values (Δα) show greater complexity in the study area, while the decrease in (Δα) may be indicative of adjustment of forms. The lacunarity values are very low, suggesting high intensity of dissection and homogeneity of the pattern of the system. This study may provide a basis for priority ranking for land conservation measures and in monitoring thereof in the badland areas.

Hot spots of extreme precipitation change under 1.5 and 2 °C global warming scenarios

Climate change hot spots are the regions where the climate variables are particularly responsive to global warming. This study quantifies the hot spots of extreme precipitation based on the simultaneous changes in the intensity (ΔI), frequency (ΔF), and interannual variability (Δσ) of extreme precipitation index under the 1.5 and 2 °C warming levels with respect to the period of 1986–2015. To investigate whether the hot spots would change as extreme precipitation index alters, precipitation extremes are defined based on the 90th, 95th, 99th, and 99.9th percentiles over the distribution of all wet days during 1986–2005. Daily precipitation from 15 GCMs in the CMIP5 project and the corresponding statistically-downscaled 0.25 ° × 0.25 ° dataset (NEX-GDDP) are adopted and compared. A gauge-based global precipitation product is also used to validate the extreme precipitation statistics in both datasets. The result shows that the CMIP5 GCMs and the NEX-GDDP display similar spatial patterns for percentile thresholds, ΔI, ΔF, and Δσ at global scale. Then with utilizing the Standard Euclidean Distance method, four aggregated indices (R90, R95, R99, and R99.9) are constructed to represent the comprehensive changes in extreme precipitation indices in the 1.5 and 2 °C warming levels. It is found that Sahara emerges as a hot spot of extreme precipitation change in both warming levels for R90, R95, and R99. Model spread in R99.9 is very large indicating large uncertainty in CMIP5 GCMs in the tail of the precipitation distribution. Comparison of the results for the two warming levels indicates that a smaller warming of 0.5 °C would lead to a reduction in the magnitude of extreme precipitation by about 7%–8% over global land regions. In addition, the values of ΔI, ΔF, and Δσ of P90, P95, and P99 are comparable for both warming levels, while the interannual variability of P99.9 responds more obviously to global warming than the intensity and frequency.

Therapeutic effect of a novel bioactive glass-ceramics on early caries lesions: a single-center, randomized controlled clinical trial.

To investigate the therapeutic effect of a novel bioactive glass-ceramics (BGC) called Huaxi BGC (HX-BGC) on early caries lesions. A total of 195 patients who meeting inclusion criteria were recruited and randomized to three groups in a 1:1:1 ratio. The patients in the treatment group received fluoride varnish which contained 5% sodium fluoride (NaF) or distilled water which contained 7.5% HX-BGC once a month for 3 months, and the control group received placebos. Quantitative light-induced fluorescence (QLF) images were taken at baseline and at the 1-month and 3-month follow-ups. The three groups had similar baseline characteristics, including age, gender, and QLF parameters (ΔF, area, and ΔQ). Compared with baseline, the ΔQ values were significantly decreased in the HX-BGC and NaF groups at 1 and 3 months (p<0.005), while no statistically significant changes were found in that of the control group. After adjusting for baseline measurements, both of the 5% NaF and 7.5% HX-BGC showed a significant therapeutic effect in the treatment of initial enamel lesions at 1 month and 3 months, when compared to those receiving placebos (ΔQ, p<0.05). Moreover, the ΔQ value of the HX-BGC group decreased by a slightly more amount than that of the NaF group at 1 month (p=0.048). Similar trends were also found for the values of ΔF and area. Our results suggest that HX-BGC may serve as a promising bioactive material for the treatment of early caries lesions. HX-BGC holds a great promise to be used as a novel bioactive material for the treatment of early caries lesions.

Exploiting the properties of TiO2 thin films as a sensing layer on (MEMS)-based sensors for radiation dosimetry applications

In this work, we investigate the potential of exploiting TiO2 thin films as sensing layers on silicon micro-electromechanical systems for the detection of gamma radiations. All samples are exposed to gamma rays produced by 60Co, with different doses ranging from 0 kGy to 40 kGy. Properties of silicon coated with a 200-nm-thick layer of TiO2 grown at 200 °C by atomic layer deposition are studied before and after its gamma irradiation using x-ray diffraction (XRD), scanning electron microscopy, and spectroscopic ellipsometry. Atomic force microscopy (AFM) is carried out on functionalized microcantilevers to measure the resonance frequency shift (Δf 0) resulting from irradiation of the TiO2 thin film. XRD results show a change in the films from a mixture of rutile and anatase phases to an anatase phase upon irradiation. Spectroscopic ellipsometry results show a change with a fixed pattern in the film thickness, roughness, void, and optical constants with different irradiation doses. This pattern appears as Δf 0 in AFM, where the response of sensors to doses between 0 kGy and 20 kGy was linear. The values of Δf 0 are convenient to control parameters for the proposed dosimeter, which is characterized by the reproducibility and sensitivity of measurements. The maximum detectable linear effect of the proposed dosimeter was found at a dose of 20 kGy. This makes a 200-nm thin layer of TiO2 coated on a microcantilever surface, a possible candidate for dosimetry for the range lower than 20 kGy applications, such as in personal dosimeters.

Hydrodynamics in Acute Ischemic Stroke Catheters Under Static and Cyclic Aspiration Conditions.

Previous studies have suggested improved recanalization efficiency by using cyclic aspiration as opposed to static aspiration for mechanical thrombectomy in the treatment of acute ischemic stroke (AIS). However, there has not been an investigation into which parameters optimize this theoretical approach. Therefore, this study was designed to investigate the application of static and cyclic pressure in AIS aspiration catheters. An experimental flow system was designed to apply and measure both static and cyclic aspiration pressures in four commercial aspiration catheters. A medical aspirator and solenoid-valve were used to generate a range of applied pump pressures and cyclic valve frequencies. The measured mean and oscillatory pressure amplitudes were analyzed and compared across catheters and operating conditions. The greatest mean pressures and forces were achieved under contact-aspiration conditions using the largest diameter catheter, while the largest oscillating pressure (ΔP) and force (ΔF) values were generated in the least compliant catheter, determined to be proportional to both its inner radius and wall thickness. Furthermore, lower frequency cyclic aspiration was able to generate the largest values of ΔP and ΔF. For future investigations of cyclic aspiration AIS therapy, the best options are to use large inner diameter and low compliance catheters operating at lower cyclic frequencies to generate the greatest mean and oscillating forces on lodged thromboemboli.

Facile synthesis of polypyrrole decorated chitosan-based magsorbent: Characterizations, performance, and applications in removing cationic and anionic dyes from aqueous medium

The adsorption characteristic of polypyrrole decorated chitosan-based magsorbent (MChs/Ppy) for the elimination of cationic crystal violet and anionic methyl orange dye from wastewater were explored. The characteristics of MChs/Ppy were studied by TGA, SEM/EDAX, TEM, BET, FTIR, VSM, and XRD analyses. The performance of MChs/Ppy towards the adsorption of CV and MO was investigated by the batch method. Removal performance was obtained to be 88.11 and 92.89% for CV and MO at the optimum conditions. The adsorption of CV was well described by pseudo 2nd order, while that of MO was best followed by the pseudo 1st order kinetics. The adsorption equilibrium data for both the dyes were fitted well with Langmuir adsorption isotherm with the maximum monolayer sorption capacity of 62.89 and 89.29 mg/g for CV and MO, respectively. The negative values of ΔH and ΔF accompanying with the removal of both dyes specified the adsorption process to be exothermic and spontaneous. Regeneration study showed that MChs/Ppy could be reused efficaciously up to three consecutive ad−/de-sorption cycles. The combined benefits of facile synthesis, non-toxicity, and good adsorption potential towards cationic and anionic dyes along with easy magnetic separability make MChs/Ppy as a novel adsorbent.

Multi-fractal analysis for the AE energy dissipation of CO2 and CO2+ brine/water treated low-clay shales under uniaxial compressive tests

Carbon dioxide (CO2) is a promising fluid which can be used for shale gas recovery. In this study, uniaxial compressive strength tests were performed on low-clay shale samples soaked in sub-/or super- critical CO2 and its dissolved water/brine solutions for 10, 20 and 30 days. The deformation and crack evolution during the experiments were analyzed by the multi-fractal method based on the acoustic emission (AE) signals. The results show that the value of Δα (the width of the spectrum) increases with increasing soaking time, which is related to the alteration of shale’s internal structure during imbibition. Sub-or super- critical CO2+ water/brine solutions significantly decrease the strength and change the brittleness of shales, which decrease the frequencies of large and small AE signals and present low values of Δf (the relationship between small and large signal frequencies). The morphology analysis shows that samples with imbibition produce more large-scale cracks during the compression tests and tend to have right skewed distributions. From the crack closure stage to the stable/unstable crack propagation stage, the average value of Δα for soaked samples decreases, which means the structure of the AE signals becomes simpler. Super-critical conditions, which decreases the complexity of shale deformation and weakens the role of small/high signals in the AE energy release, yield a lower value of Δα than the corresponding sub-critical conditions. This study helps to understand the effect of CO2 and its saturated fluids on shales and the mechanism of cracks propagation during CO2 enhanced shale gas recovery and CO2 sequestration in shale reservoirs.

Hybrid density functional study on lattice vibration, thermodynamic properties, and chemical bonding of plutonium monocarbide**Project supported by the National Natural Science Foundation of China (Grant Nos. 21371160 and 21401173).

Hybrid density functional theory is employed to systematically investigate the structural, magnetic, vibrational, thermodynamic properties of plutonium monocarbide (PuC and PuC0.75). For comparison, the results obtained by DFT, DFT + U are also given. For PuC and PuC0.75, Fock-0.25 hybrid functional gives the best lattice constants and predicts the correct ground states of antiferromagnetic (AFM) structure. The calculated phonon spectra suggest that PuC and PuC0.75 are dynamically stable. Values of the Helmholtz free energy ΔF, internal energy ΔE, entropy S, and constant-volume specific heat Cv of PuC and PuC0.75 are given. The results are in good agreement with available experimental or theoretical data. As for the chemical bonding nature, the difference charge densities, the partial densities of states and the Bader charge analysis suggest that the Pu–C bonds of PuC and PuC0.75 have a mixture of covalent character and ionic character. The effect of carbon vacancy on the chemical bonding is also discussed in detail. We expect that our study can provide some useful reference for further experimental research on the phonon density of states, thermodynamic properties of the plutonium monocarbide.

Application of force-length curve for determination of leg stiffness during a vertical jump.

The aim of this study was to present the methodology for estimation of a leg stiffness during a countermovement jump. The question was asked whether leg stiffness in the countermovement and take-off phases are similar to each other as demonstrated in previous reports. It was also examined whether the stiffness in left lower limb is similar to the one in right lower limb. The research was conducted on 35 basketball players. Each participant performed three countermovement jumps with arm swing to the maximum height. Measurements employed a Kistlerforce plate and a BTS SMART system for motion analysis. Leg stiffness (understood as an inclination of the curve of ground reaction forces vs. length) was computed for these parts of countermovement and take-off phases where its value was relatively constant and F(Δl) relationship was similar to linear. Mean value (±SD) of total stiffness of both lower limbs in the countermovement phase was 7.1 ± 2.3 kN/m, whereas this value in the take-off phase was 7.5 ± 1 kN/m. No statistically significant differences were found between the leg stiffness in the countermovement and the take-off phases. No statistically significant differences were found during the comparison of the stiffness in the right and left lower limb. The calculation methodology allows us to estimate the value of leg stiffness based on the actual shape of F(Δl) curve rather than on extreme values of ΔF and Δl. Despite different tasks of the countermovement and the take-off phases, leg stiffness in these phases is very similar. Leg stiffness during a single vertical jump maintains a relatively constant value in the parts with a small value of acceleration.

Effects of near infrared laser radiation associated with photoabsorbing cream in preventing white spot lesions around orthodontic brackets: an in vitro study.

The present study aims to investigate the effect of a low-power infrared laser on the inhibition of bovine enamel demineralization around orthodontic brackets. Near infrared lasers have been suggested as alternative approaches because they may produce an increase in resistance to dental caries. Forty-eight blocks of enamel obtained from bovine incisor teeth were divided into six groups: Group 1 (control), without treatment; Group 2 (C), photoabsorbing cream; Group 3 (CF), photoabsorbing cream with fluoride; Group 4 (L), irradiation with low-level infrared laser (λ=830 nm) at an energy density of 4.47 J/cm2; Group 5 (L+C), photoabsorbing cream followed by low-level infrared laser irradiation; and Group 6 (L+CF), photoabsorbing cream with fluoride followed by low-level infrared laser irradiation. After these procedures, the enamel blocks received an assortment of orthodontic brackets and were then submitted to pH cycling to simulate a highly cariogenic challenge. The enamel surface demineralization around the orthodontic brackets, according to the different treatments, was quantified by fluorescence loss analysis by quantitative light-induced fluorescence (QLF). The fluorescence loss, expressed as ΔF (percentage of loss fluorescence), was statistically examined by analysis of variance and the Tukey test. The control group (-10.48±2.85) was statistically similar to Group C (-14.52±7.80), which presented the lowest values of ΔF when compared with Groups FC (-3.67±3.21), L (-2.79±1.68), CL (-1.05±0:50), and CFL (-0.60±0:43). However, Groups FC, L, CL, and CFL showed no statistically significant differences among them. It can be concluded that both the low-level infrared laser and photoabsorbing cream with fluoride were effective in inhibiting the development of caries in enamel around orthodontic brackets, even in situations of high cariogenic challenge.

Further tests of the local nonlinear interaction-based mechanism for simultaneous suppression of tone burst-evoked otoacoustic emissions

Tone burst-evoked otoacoustic emission (TBOAE) components measured in response to a 1 kHz tone burst (TB1) are suppressed by the simultaneous presence of an additional tone burst (TB2). This “simultaneous suppression of TBOAEs” has been explained in terms of a mechanism based on local nonlinear interactions between the basilar membrane (BM) travelling waves caused by TB1 and TB2. A test of this local nonlinear interaction (LNI)-based mechanism, as a function of the frequency separation (Δf, expressed in kHz) between TB1 and TB2, has previously been reported by Killan et al. (2012) using a simple mathematical model [Killan et al., Hear. Res. 285, 58–64 (2012)]. The two experiments described in this paper add additional data on the extent to which the LNI-based mechanism can account for simultaneous suppression, by testing two further hypotheses derived from the model predictions. Experiment I tested the hypothesis that TBOAE suppression is directly linked to TBOAE amplitude nonlinearity where ears that exhibit a higher degree of amplitude nonlinearity yield greater suppression than more linear ears, and this relationship varies systematically as a function of Δf. In order to test this hypothesis simultaneous suppression at a range of values of Δf at 60 dB peak-equivalent sound pressure level (p.e. SPL) and TBOAE amplitude nonlinearity from normal human ears was measured. In Experiment II the hypothesis that suppression will also increase progressively as a function of increasing tone burst level was tested by measuring suppression for a range of Δf and tone burst levels at 40, 50, 60 and 70 dB p.e. SPL. The majority of the findings from both experiments provide support for the LNI-based mechanism being primarily responsible for simultaneous suppression. However, some data were inconsistent with this view. Specifically, a breakdown in the relationship between suppression and TBOAE amplitude nonlinearity at Δf = 1 (i.e. when TB2 was reasonably well separated from, and had a higher frequency than TB1) and unexpected level-dependence, most notably at Δf = 1, but also where Δf = −0.5, was observed. Either the LNI model is too simple or an alternative explanation, involving response components generated at basal regions of the basilar membrane, is required to account for these findings.

High brightness InP micropillars grown on silicon with Fermi level splitting larger than 1 eV.

The growth of III-V nanowires on silicon is a promising approach for low-cost, large-scale III-V photovoltaics. However, performances of III-V nanowire solar cells have not yet been as good as their bulk counterparts, as nanostructured light absorbers are fundamentally challenged by enhanced minority carriers surface recombination rates. The resulting nonradiative losses lead to significant reductions in the external spontaneous emission quantum yield, which, in turn, manifest as penalties in the open-circuit voltage. In this work, calibrated photoluminescence measurements are utilized to construct equivalent voltage-current characteristics relating illumination intensities to Fermi level splitting ΔF inside InP microillars. Under 1 sun, we show that splitting can exceed ΔF ∼ 0.90 eV in undoped pillars. This value can be increased to values of ΔF ∼ 0.95 eV by cleaning pillar surfaces in acidic etchants. Pillars with nanotextured surfaces can yield splitting of ΔF ∼ 0.90 eV, even though they exhibit high densities of stacking faults. Finally, by introducing n-dopants, ΔF of 1.07 eV can be achieved due to a wider bandgap energy in n-doped wurzite InP, the higher brightness of doped materials, and the extraordinarily low surface recombination velocity of InP. This is the highest reported value for InP materials grown on a silicon substrate. These results provide further evidence that InP micropillars on silicon could be a promising material for low-cost, large-scale solar cells with high efficiency.

Thermodynamic investigation on MTe2O6 (M = Th, Ce)

The standard Gibbs energies of formation of MTe2O6 (s) (where M=Th, Ce) were derived from vapour pressure measurements by employing thermogravimetry (TG) based transpiration technique. The vapour pressures of TeO2 (g) over the mixtures MTe2O6 (s)+MO2 (s) generated by the incongruent vapourisation reaction, MTe2O6 (s)→MO2 (s)+2 TeO2 (g) were measured in the temperature range 1034–1167K and 986–1129K for ThTe2O6 (s) and CeTe2O6 (s) respectively. From the vapour pressure measurements the standard Gibbs energies of formation of MTe2O6 (s) were derived. The derived values of Δf G∘<ThTe2O6, s>and Δf G∘<CeTe2O6, s>were combined with free energy functions to obtain ΔfH298K∘ of ThTe2O6 (s) and CeTe2O6 (s).

Thermodynamic characteristics of the water weakly bound with the surface of layer silicates

The isochoric-isothermal potential ΔF of the interaction of weakly (osmotically) bound water with the kaolinite surface has been determined. In terms of magnitude this potential does not exceed 1.5% of free surface energy of kaolinite. The heat released during the interaction of boundary layers of water with kaolinite is evaluated. This heat is positive (enthalpy −ΔH = Q is negative) and does not exceed 1% of total integral heat of wetting. Entropy ΔS of weakly bound water is determined from the values of ΔF and ΔH.The entropy is compared with the excess entropy of surface layers of liquid water. The positive sign of the entropy indicates a larger disorder of the structure of boundary layers as compared with the bulk phase. Judging from the relationship between ΔH and TΔS the osmotic swelling of clays is determined just by the entropy component of the isochoric-isothermal potential.

Norovirus GII.4 virus-like particles recognize galactosylceramides in domains of planar supported lipid bilayers.

A sticky situation: Domain-dependent recognition of the glycosphingolipid galactosylceramide by norovirus-like particles (see picture; red/yellow) is shown using supported lipid bilayers (purple) as model membranes. Optimal ligand presentation is found to promote strong binding to GalCer. This presentation can be found at the edges of the glycosphingolipid-enriched domains (green) and binding is repressed in the absence of these domains.