Positive Volume Change Research Articles

Midface Projection Using Biostimulatory Poly- l -Lactic Acid Injectable Implant: A Subgroup Analysis of the Cheek Wrinkle Trial.

Correction of cheek wrinkles using poly- l -lactic acid (PLLA-SCA) was demonstrated in a 12-month study. This analysis assessed change from baseline in lifting effect of PLLA-SCA using a 3D camera to provide additional quantified data. Subjects received PLLA-SCA (reconstituted in 8 mL of sterile water + 1 mL of 2% lidocaine) in both cheeks or no treatment (control). Assessments included the Galderma Cheek Wrinkle Scale (GCWS), aesthetic improvement, and 3D photography. In subjects with severe GCWS at baseline, Canfield software analyzed 3D images for change from baseline in midface volume projection and volume change of both cheeks at Month 9. The primary study showed a statistically significant higher at-rest GCWS responder rate at Month 12 for PLLA-SCA, 71.6%, versus control, 26.1% ( p < .0001). In this Month 9 analysis, mean midface volume projection demonstrated a positive volume shift for PLLA-SCA (left: 0.45 mm; right: 0.34 mm; n = 46) versus control (left: 0.25 mm; right: -0.01 mm; n = 21). Midface volume and max projection changes for PLLA-SCA were +4.88 mL/+1.62 mm (left), +2.84 mL/+1.12 mm (right) versus +0.26 mL/+0.34 mm (left), +0.68 mL/+0.37 mm (right) for control. Poly- l -lactic acid-treatment of subjects with severe GCWS had a clinically meaningful lifting effect in both cheeks (positive volume shift, positive volume change, and max projection) in the midface. NCT04124692.

Degradation of the 2014–2015 Holuhraun vent-proximal edifice in Iceland

AbstractThe earliest stages of volcanic vent degradation are rarely measured, leaving a gap in the knowledge that informs landform degradation models of cinder cones and other monogenetic vent structures. We documented the initial degradation of a 500-m-long spatter rampart at the primary vent of the 2014–2015 Holuhraun eruption in northern Iceland with high-resolution topographic change maps derived from terrestrial laser scanning (TLS) and photogrammetric surveys using an unoccupied aircraft system (UAS). Topographic differencing shows a total negative volume change of 42,637 m3, and a total positive volume change (basal deposition) of 10,304 m3 (primarily as deposition at the base of steeply sloping surfaces). Two distinct styles of volume changes were observed on the interior and exterior of the spatter rampart. Material on the interior of the vent was removed from oversteepened slopes by discrete rockfalls, while diffusive processes were qualitatively evident on the exterior slopes. We propose a novel conceptual landform evolution model for spatter ramparts that combines rockfall processes on the interior walls, diffusive gravitational sliding on the exterior slopes, and incorporates cooling contraction and compaction over the entire edifice to describe the observed modes of topographic change during the onset of degradation. Potential hazards at fresh spatter ramparts are rockfalls at high slope areas of the vent interior walls where contacts between spatter clasts are prone to weakening by fumarolic activity, weathering, and settling. To capture such hazards, our data suggest a cadence for monitoring changes yearly for the first few years post-eruption, and at longer intervals thereafter.

Radiomic-Based Prediction of Lesion-Specific Systemic Treatment Response in Metastatic Disease.

Cancer is a heterogenous, dynamic target. Individual patients, lesions, and cell populations may present with different characteristics and varying sensitivities to anticancer therapies. The purpose of this study was to investigate the utility of image-derived (radiomic) biomarkers for prediction of lesion-specific treatment response. Using a database of serial imaging from a Phase III clinical trial (NCT01440088), all visible lung metastases were contoured on chest computed tomography performed at baseline and after 2 cycles of chemotherapy. Metastatic leiomyosarcoma patients received either doxorubicin monotherapy (DM) or doxorubicin plus evofosfamide (DE). Percent change in volume with respect to baseline was evaluated as a metric of treatment response. Lesions that experienced a positive volume change greater than 50% were labeled as 'progressors'; all other lesions were labeled as 'non-progressors'. Radiomic features were extracted at baseline from the whole lesion and three peritumoral regions using PyRadiomics (version 3.0.1). Features were compared using the Mann-Whitney U-test and further used to classify between response categories. Logistic classification models were evaluated with 10-fold cross-validation using Area Under the Curve for the Receiver Operating Characteristic (AUROC) and Precision-Recall (AUPRC) curves as measures of model performance. Significance was evaluated by permutation tests. All code used to derive features is open source and available for download. In total, 204 lung metastases from 80 patients were evaluated. The fraction of progressing lesions was 19% and 27% for the DM and DE regimes, respectively. Differences in individual lesion response were observed in 20% of patients with multiple lung metastases. Significant differences in entropy were observed between response categories (false discovery rate < 5% after multiple testing correction): interior regions for lesions receiving DM, and peripheral regions for lesions receiving DE. The best performing models for the DM and DE regimens had AUROC of 0.87 and 0.76 and AUPRC 0.60 and 0.50, respectively (p < 0.05). Predicting lesion-specific responses using radiomic features represents a paradigm shift. Lesion-specific radiomic models indicate a 2 to 3-fold increase in predictive capacity in comparison to a no-skill classifier. These models, although preliminary, achieved a strong predictive value and could be used to predict lesion-specific treatment response.

The volume changes of unfolding of dsDNA

High hydrostatic pressure can have profound effects on the stability of biomacromolecules. The magnitude and direction (stabilizing or destabilizing) of this effect is defined by the volume changes in the system, ΔV. Positive volume changes will stabilize the starting native state, whereas negative volume changes will lead to the stabilization of the final unfolded state. For the DNA double helix, experimental data suggested that when the thermostability of dsDNA is below 50°C, increase in hydrostatic pressure will lead to destabilization; i.e., helix-to-coil transition has negative ΔV. In contrast, the dsDNA sequences with the thermostability above 50°C showed positive ΔV values and were stabilized by hydrostatic pressure. In order to get insight into this switch in the response of dsDNA to hydrostatic pressure as a function of temperature, first we further validated this trend using experimental measurements of ΔV for 10 different dsDNA sequences using pressure perturbation calorimetry. We also developed a computational protocol to calculate the expected volume changes of dsDNA unfolding, which was benchmarked against the experimental set of 50 ΔV values that included, in addition to our data, the values from the literature. Computation predicts well the experimental values of ΔV. Such agreement between computation and experiment lends credibility to the computation protocol and provides molecular level rational for the observed temperature dependence of ΔV that can be traced to the hydration. Difference in the ΔV value for A/T versus G/C basepairs is also discussed.

The Underappreciated Role of the Platysma Muscle in the Perioral Expressions in Young Adults.

The platysma is involved in lower face movement, yet limited information on its functional role when making perioral expressions is available. The aim of this study was to use 3-dimensional (3D) photogrammetry to analyze platysma activity when making expressions. Standardized frontal-view 3D images were obtained from 54 volunteers. Three perioral expressions were analyzed: a full smile, mouth corner depression, and a grimace to show the lower teeth. Positive volume change in the "heat map" of the neck skin surface-determined by the superimposed image subtraction technique-served as a sensitive indicator of platysma contraction. When making the 3 expressions, the proportions of platysma contraction were 42.6%, 75.9%, and 92.6%, respectively. The platysma worked as a more critical dynamic force than expected. In most smiles involving the platysma, its upper portion contracted. With the laterally downward traction on the lower lip increasing, the upper and lower portions of the platysma contracted together and formed muscular bands. The platysma contracted extensively in the other 2 expressions. In some cases, platysma bands were observed to form due to vigorous contraction of muscle fibers. In addition, the platysma was found to be highly functionally active in young individuals. This study introduced a simple method that can sensitively identify the functional status of the platysma. The results showed the platysma's highly active function in perioral expressions in young adults. These findings may assist surgeons in personalized decision-making toward platysma muscle-weakening strategies and work as an objective tool for outcome evaluation.

The Role of Metamorphic Fluid in Tectonic Tremor Along the Alpine Fault, New Zealand

AbstractThe production of H2O during metamorphism along active plate boundaries is inferred to contribute to low‐frequency tectonic tremor. This study combines predictions from phase equilibria and mechanical modeling of coincident volume changes to investigate links of tremor with hydrofracturing and fluid migration under the actively forming Southern Alps, New Zealand. The posited location of metamorphic fluid production correlates with published geophysical images of inferred permeability enhancement, fluid accumulation and potential fluid flow. As the hanging‐wall rocks are translated toward the surface by motion along the Alpine Fault, they can undergo metamorphic reactions that involve positive volume changes. Production of metamorphic fluids leads to hydrofracturing and the development of tremor hypocenters in regions along, and above deep reflectors of the Alpine Fault. The capacity of metamorphic rocks to generate or consume fluid along portions of the pressure–temperature path exerts a fundamental control on the distribution of stresses in the crust.

The spatio-temporal relationship between white matter lesion volume changes and brain atrophy in clinically isolated syndrome and early multiple sclerosis

BackgroundWhite matter lesions and brain atrophy are both present early in multiple sclerosis. However, the spatio-temporal relationship between atrophy and lesion processes remains unclear. MethodsYearly magnetic resonance images were analyzed in 392 patients with clinically isolated syndrome from the 5-year REFLEX/REFLEXION studies. Patients received early treatment (from baseline; N = 262) or delayed treatment (from month-24; N = 130) with subcutaneous interferon beta-1a. Global and central atrophy were assessed using FSL-SIENA to provide yearly percentage volume change of brain and ventricles, respectively. Yearly total lesion volume change was calculated by subtracting the sum of the negative lesion volume change (disappearing + shrinking) from the positive lesion volume change (new + enlarging) for each yearly interval, as determined by an in-house developed semi-automated method. Using linear mixed models, during the period where patients had received ≥1 year of treatment, we investigated whether total lesion volume change was associated with percentage brain volume change or percentage ventricular volume change in the next year, and vice versa. ResultsHigher total lesion volume change was related to significantly faster global atrophy (percentage brain volume change) in the next year (B = − 0.113, SE = 0.022, p < 0.001). In patients receiving early treatment only, total lesion volume change was also associated with percentage ventricular volume change in the next year (B = 1.348, SE = 0.181, p < 0.001). Voxel-wise analyses showed that in patients receiving early treatment, higher total lesion volume change in years 2, 3, and 4 was related to faster atrophy in the next year, and in year 4 this relationship was stronger in patients receiving delayed treatment. Interestingly, faster atrophy was related to higher total lesion volume change in the next year (percentage brain volume change: B = − 0.136, SE = 0.062, p = 0.028; percentage ventricular volume change: B = 0.028, SE = 0.008, p < 0.001). ConclusionsHigher lesion volume changes were associated with faster atrophy in the next year. Interestingly, there was also an association between faster atrophy and higher lesion volume changes in the next year.

Crustal Melting Evidence in Migmatites of Higher Himalayan Crystallines (HHC) along Bhagirathi, Dhauliganga Valleys, and Sikkim Himalaya, India

Abstract An attempt has been made to evaluate crustal melting evidence through textural studies within a narrow zone of migmatite present in NW Himalaya along Bhagirathi and Dhauliganga valleys and two zones close to MCT and throughout within in the Sikkim Himalayas, NE Himalaya. It appears that partial melting was initiated by muscovite dehydration melting with a positive volume change driving melt segregation and discontinuous crystallization of peritectic biotite in the leucosome. Further, during retrogression due to cooling, a certain amount of melt was consumed. The occurrence of isolated pseudomorphosed melt pockets and lack of euhedral magmatic flow textured feldspar further indicates that the melt fraction was low for the alignment of crystals. The processes of melt segregation and migration could have been limited. The migmatite leucosomes and a small volume of in situ tourmaline-bearing leucogranite along extensional crenulation cleavages and melt pods indicate water-saturated melting of pelitic metasedimentary rocks. The formation of migmatites happened at around 46 Ma, corresponding to a peak metamorphic event due to collisional tectonics of the Himalayan orogeny. The presence of feeder dikes for main tourmaline-bearing leucogranite indicates that the source for the main body could be migmatite which is also supported by the similarity in REE patterns of the main body and in situ tourmaline-bearing leucogranite.

Monoclinic–Orthorhombic Phase Transition with a Positive Volume Change in the Siliceous Zeolite Mobil-Five Induced by the High-Pressure Insertion of Dense Fluid Helium

Synchrotron X-ray diffraction was used to investigate the insertion of helium in the archetypal siliceous zeolite Mobil-Five (MFI). Due to the very high degree of helium penetration into the pores ...

Investigation of Delamination-Induced Performance Decay at the Cathode/LLZO Interface

The growing interest in solid-state batteries has resulted in increased focus on the issue of delamination at the cathode/solid-state electrolyte (SSE) interface. The extent of delamination, and its impact on impedance rise and capacity fade, is determined by a number of material properties, including cathode molar volume change and state-of-charge dependence, mechanical properties of the cathode and SSE, SSE grain boundary microstructure, fracture threshold of the interface, and interfacial exchange current density. The goal of this paper is to develop multiscale mathematical models to link these material properties to performance and provide guidance on possible approaches to minimize delamination, impedance rise, and capacity fade. We examine two cathodes, namely, LiNi0.8Mn0.1Co0.1O2 with a positive molar volume change and LiCoO2 with a negative molar volume change against a Li7La3Zr2O12 (LLZO) SSE. Density functional theory (DFT) is used to determine fundamental material properties at the interface, while mesoscale models are used to link these properties to macroscopic performance. Model results suggest that SSEs with smaller grains and low Young’s modulus and cathodes with low molar volume changes provide opportunities for minimizing delamination.

Hydrogel-driven origami metamaterials for tunable swelling behavior

Origami metamaterial has gradually shown its potential in the fields of science and engineering due to its unique mechanical behaviors. Since hydrogel shows a positive volume change when absorbing water, it provides a new design strategy for actively deformed origami metamaterials composed of normal material framework and active hydrogel layer. In this paper, we proposed three synergistic mechanical designs with positive/negative/zero tunable swelling deformation by adjusting the opening direction of the circular holes. The deformation behaviors of the origami metamaterials manufactured by a multi-material 3D printer were qualitatively and quantitatively characterized and demonstrated, using finite element analysis, experimental test and theoretical method. The results indicate that the origami metamaterials present significant tunable swelling behaviors, which can be customized by adjusting the lattice microstructure geometry parameters. Utilizing the origami metamaterials, cylindrical shell and box structures with tunable swelling behavior were designed. Additionally, the hydrogel-driven actuator based on the origami metamaterials was manufactured to pull/drag an underwater object. Since the tunable swelling behaviors are not related to scale, these hydrogel-driven origami metamaterials can be applied to the design of reconfigurable and programmable devices on the macro and micro scale and possess promising potential for wide applications in bioelectronics and biological tissue engineering.

A review and synthesis of strain studies in the Egyptian Nubian Shield: materials, methods, problems and prospects

More than seventy strain studies in the Egyptian Nubian Shield (ENS) are reviewed in this contribution. For the Hammamat basin strain studies, Rf/ϕ and Fry methods have been applied to pebble sections, mudcracks and raindrop prints. Consideration of pebble fabrics in undeformed outcrops suggests that RXZ estimates of less than 1.7 based on pebble ellipse data are doubtful. Extracted pebbles are also popular strained objects for analysis. Average Wadell sphericity and percentage of blades assist recognition of pebble strains in the Kareim, Queih, Igla and Seleimat basins. Feiran gneissic complex strains, measured using boudins and folds are much higher (X/Z > 15) than the reported strains for the Hafafit gneissic complex (X/Z usually < 2.5) that used metamorphic grain shapes and centres. The low Hafafit strains may result from progressive resetting of grain shapes and relocation of grains by diffusional effects during HT metamorphism. The Barramiya-Mubarak thrust belt provides a good example of focused study on ENS shear zones strain, with variable correlations between Rf/ϕ and Fry results, but consistently low k values. South Eastern Desert (SED) shear zone prolate strain ellipsoids record the effects of multiple deformation. The extensional shear zone overlying the Meatiq complex shows extreme strain and strongly prolate strain ellipsoids. ENS vorticity studies, applying PAR and RGN methods, have yielded higher Wm (> 0.5) for transpressional shears (Barramiya-Mubarak belt and Atalla shear zone) than for transtensional shears (Wm < 0.5). Volume strains have rarely been considered in the ENS, though evidence exists for negative (due to pressure solution) and positive (due to microveining) volume change during deformation. The ENS strain database can be improved by better documentation of sampling methods; better knowledge of primary fabrics; and by testing strain results using a range of materials. AMS-strain studies may broaden the range of lithologies suitable for strain measurement.

Volume and compressibility changes on mixing solutions of alkali halides/sodium acetate with sodium salt of butyric acid at 298.15 K: Understanding like charge ionic (anion–anion) interactions in water

Excess molar volumes of mixing (ΔmVex) and excess adiabatic compression of mixing (Δm(βV)ex) have been calculated by measuring density and sound velocity data for aqueous binary and ternary solution involving sodium acetate-NaBr, sodium acetate-KBr, sodium acetate-KI, sodium butyrate-NaBr, sodium butyrate-KBr, sodium butyrate-KI (in the concentration region 0.0993–1.0929 mol·kg−1 and at ionic strength of 1.0 in ternary solutions) and sodium acetate‑sodium butyrate (in the concentration region 0.1022–1.8480 mol·kg−1 and at ionic strength of 0.5, 1.0 and 2.0 in ternary solutions) at 298.15 K. The density and sound velocity measurements are also reported for the aqueous binary solutions of studied electrolytes at 298.15 K and the data were utilized for the determinations of the apparent molar volume and apparent molar compressibility values at finite concentrations. Friedman's theory has been applied to the data for volume of mixing AX and BX as well for hetero combinations of ions to obtain the coefficients required to assess the contributions to volume changes on mixing due to the structural effects and ion-ion interactions (cation–cation, anion–anion and cation–anion–cation interactions in case of sodium acetate‑sodium butyrate solutions, common cation AX-AY and other heteroionic combinations. Similar calculations were made for adiabatic compressibility data and Δm(βV)ex are obtained. The studies reveal that the ΔmVex and Δm(βV)exvalues for all systems exhibit parabolic behaviours as a function of ‘y’ (fraction of ionic strength of an electrolyte (AX) in the mixture of two electrolytes (AX + BX or other combinations) in water at 298.15 K. The magnitudes of ΔmVex are in the order of CH3(CH2)2COONa + KI ≈ CH3(CH2)2COONa-CH3COONa > CH3(CH2)2COONa + KBr > CH3(CH2)2COONa + NaBr while the magnitudes of Δm(βV)ex are in the order of CH3(CH2)2COONa + KBr > CH3(CH2)2COONa + CH3COONa > CH3(CH2)2COONa + NaBr > CH3(CH2)2COONa + KI at ionic strength of 1.0. Similar trends were obtained for ternary solutions having compounds CH3COONa + NaBr/KBr/KI but having smaller magnitudes of ΔmVex and Δm(βV)ex at ionic strength of 1.0. The observed positive volume changes and negative compressibility changes have been interpreted in terms of hydrophobic interactions of anions, size and polarizability of anions as well the H-bonding with water molecules causing alteration in cosphere water contribution which may be of constructive type cosphere overlap due to anion–anion interactions.

Measurement of Volume Change and Mass Transfer During Serpentinization: Insights From the Oman Drilling Project

AbstractSerpentinization plays a key role on the evolution of the physicochemical properties of the mantle lithosphere. The rate of serpentinization reactions is controlled by the transport of fluid, which itself depends on volume change during reaction. Element transfer can strongly modify the magnitude and sign of volume change. Here, we measure solid volume change and element transport perpendicular to a serpentine vein in a serpentinized dunite collected at depth during the Oman Drilling Project. The sample is extensively replaced (extent of reaction &gt; 80%) by a serpentine/brucite mixture parallel to a main serpentine vein network. The Mg content of serpentine and brucite indicates reaction with a small amount of fluid at temperatures below 100°C. Concentrations of fluid‐mobile trace elements (Na, Ca, Sr, Rb, and Ba) decrease perpendicular to the main vein. Primary olivine contains parallel platelets of a clinopyroxene/magnetite symplectite. Tomography at the nanoscale reveals that these inclusions do not react during serpentinization but are cracked and displaced. We use these inert markers to measure a 59% to 74% positive volume change that is close to the 52% expected for reaction in a closed system. Chemical data indicate no change in major element composition during reaction except for the addition of water. The initial olivine zoning in Al, Ti, V, Sc, and Cr is still preserved in serpentine and brucite. Serpentinization can thus be a local replacement process during which the solid volume homogeneously increases at the micrometer scale and the transport of aqueous species is limited.

Volumetric studies of solvation of carboxylic acids in aqueous, carbon tetrachloride, methanolic and methanolic-urea binary solutions at 298.15 K

Abstract Experimental measurements of density property at 298.15 K for aqueous, carbon tetrachloride, methanolic, and 3.0004 mol·kg−1 urea in methanol as solvent systems for binary solutions of carboxylic acids (propionic acid, n-butyric acid, n-valeric acid and n-caproic acid) are reported. The data of density are used to obtain apparent molar volume of acids at the finite concentrations of solute (Vϕ) which were appropriately extrapolated to infinitely dilute concentration of acid to obtain the limiting apparent molar volumes (Vϕ0). The calculations of volume changes due to dimerization equilibria (in carbon tetrachloride and aqueous solutions) are made and used to study the volume changes due to dimerization of acid molecules. The results of Vϕ in methanol-urea solvent system are explained on the basis of channel-like structure-formation for the species (urea and acid molecules) in solution phase. The negative volume changes observed in case of aqueous solutions are explained on the basis of hydrophobic hydration while the same in carbon tetrachloride solutions occurring with positive volume changes are interpreted in terms of hydrogen-bonded dimer formation equilibria. The Vϕ variation with acid concentrations has been explained on the basis of solute-solvent interactions foe studied acids in methanol while in aqueous solutions, the same has been attributed to ionization (limiting concentration range), hydrogen bonding and hydrophobic interactions.

Estimation groundwater total recharge and discharge using GIS-integrated water level fluctuation method: a case study from the Alaşehir alluvial aquifer Western Anatolia, Turkey

The estimation of groundwater recharge is an essential process for hydrogeological study. Realistic determination approach is crucial for assessing groundwater potential in an aquifer system and estimating of groundwater levels and/or changes in dry periods. Based on these matters, we employ a GIS-integrated groundwater level fluctuation method to determine the groundwater recharge for a hydrological period in the Alasehir alluvial aquifer (W. Anatolia). The method basically takes into account both increasing and decreasing of the groundwater levels due to the recharge and discharge mechanisms in the aquifer. In this study, 16 pumping and monitoring wells were drilled with a total depth of 1300 m, and water level data loggers were installed into the monitoring wells to determine the groundwater level changes. The spatial distribution of the monthly groundwater level change map was multiplied by the aquifer storage distribution map and then the accurate water volume is calculated by using the 3-D spatial analysis. According to our evaluation in the aquifer, positive volume change of the groundwater is 187 hm3 in a year, which is considered as a recharge value of groundwater. It is concluded that the GIS-integrated water table fluctuation method gave rise to estimate the total recharge amount of the groundwater in the Alasehir aquifer. The total groundwater recharge indicates that total inflow in the aquifer from precipitation, leakage from surface water and irrigation waters. It can be stated that the recharge estimation of groundwater in a surficial aquifer, like the Alasehir aquifer, is fairly easy using the GIS-integrated water table fluctuation method.

DNA Hairpin Hybridization under Extreme Pressures: A Single-Molecule FRET Study.

Organisms have evolved to live in a variety of complex environments, which clearly has required cellular biology to accommodate to extreme conditions of hydraulic pressure and elevated temperature. In this work, we exploit single-molecule Forster resonance energy transfer (FRET) spectroscopy to probe structural changes in DNA hairpins as a function of pressure and temperature, which allows us to extract detailed thermodynamic information on changes in free energy (ΔG°), free volume (ΔV°), enthalpy (ΔH°), and entropy (ΔS°) associated with DNA loop formation and sequence-dependent stem hybridization. Specifically, time-correlated single-photon counting experiments on freely diffusing 40A DNA hairpin FRET constructs are performed in a 50 μm × 50 μm square quartz capillary cell pressurized from ambient pressure up to 3 kbar. By pressure-dependent van't Hoff analysis of the equilibrium constants, ΔV° for hybridization of the DNA hairpin can be determined as a function of stem length (nstem = 7-10) with single base-pair resolution, which further motivates a simple linear deconstruction into additive stem (ΔV°stem = ΔV°bp x nstem) and loop (ΔV°loop) contributions. We find that increasing pressure destabilizes the DNA hairpin stem region [ΔV°bp = +1.98(16) cm3/(mol bp)], with additional positive free volume changes [ΔV°loop = +7.0(14) cm3/mol] we ascribe to bending and base stacking disruption of the 40-dA loop. From a van't Hoff temperature-dependent analysis of the DNA 40A hairpin equilibria, the data support a similar additive loop/stem deconstruction of enthalpic (ΔH° = ΔH°loop + ΔH°stem) and entropic (ΔS° = ΔS°loop + ΔS°stem) contributions, which permits insightful comparison with predictions from nearest-neighbor thermodynamic models for DNA duplex formation. In particular, the stem thermodynamics is consistent with exothermically favored (ΔH°stem < 0) and entropically penalized (ΔS°stem < 0) hydrogen bonding but with additional enthalpic (ΔH°loop > 0) and entropic (ΔS°loop > 0) contributions due to loop bending effects consistent with distortion of dA base stacking in the 40-dA linker.

Phase equilibria in CaNaPO4-CaKPO4 system and their influence on formation of bioceramics based on mixed Ca-K-Na phosphates

An investigation of the two-component phase diagram of the CaNaPO4- CaKPO4system performed using various analysis techniques is reported. The continuous solid solution series of α-CaMPO4 existing above 700 °C undergoes eutectoid decomposition during cooling to β-CaMPO4-based solid solutions enriched with Na and K, and to an intermediate nonstoichiometric compound with an ideal composition of CaK0.6Na0.4PO4. All three compounds exhibit significant volumetric effects associated with first-order phase transitions, with positive volume changes under cooling for the intermediate compound. Increased K content in ceramics based on CaKyNa1-yPO4 compositions enhances the strength properties of those ceramics, including their fracture toughness, which is associated with increased density. Increased K content also has a smaller effect of inducing phase transformations accompanied by strong volume changes.

Have Stock Markets Become Less Volatile After the Great Recession?

This paper investigates volatility modeling in light of the 2008 global financial crisis. The study was motivated by the measures and regulations introduced by most of the countries following the shock to stabilize their financial markets. The theoretical proposition is that these measures should succeed in reducing volatility which would be modeled differently following the crisis. The adopted ARMA-GARCH process included positive and negative trading volume change to capture the asymmetric effect of trading volume on market volatility for seven international markets. The results indicate that the majority of these markets were not so successful in reducing volatility following the crisis. There is evidence of volatility persistence which dissipates very quickly. Although volatility is modeled differently before and after the crisis, each market is modeled uniquely. The effect of trading volume was found to be asymmetric. Only positive change was a valid predictor. Detailed discussions of the results, implications, and recommendations are provided.

Negative and positive thermal expansion-like volume changes due to intermetallic charge transfer based on an ionic crystal model of transition-metal oxides

Materials showing negative thermal expansion (NTE) are technologically important and a few transition-metal oxides with the perovskite structure show large NTE-like volume changes due to intermetallic charge transfer. Here we show that the observed volume changes are primarily caused by the size effect of the constituent ions in the oxides. Not only the NTE-like behaviors but also the positive volume change due to the intermetallic charge transfer can be qualitatively reproduced with a simple ionic crystal model by using the SPuDS software program. The results demonstrate that materials showing NTE-like behavior due to intermetallic charge transfer can be strategically designed.