•Machine learning-based viscosity and melting temperature models were developed.•Hyperparameters were optimized through combination of grid search and manual tuning.•Developed model shows far more ...accurate prediction than those widely used models.•Feature importance on prediction was explained and evaluated using SHAP analysis.•Prediction results were visualized through property distribution diagrams.
Viscosity and melting temperature are indispensable properties for mold flux design and evaluation, significant investment is required for measurement. In this paper, viscosity and melting temperature predictive model for mold fluxes were established and trained based on 3300 groups of data and four representative machine learning algorithms. The gradient boosting regression tree (GBRT) algorithm-based model performed best prediction with the determination coefficient R2 of 0.969 and 0.900 for viscosity and melting temperature. It also far outperforms the widely used viscosity and melting temperature prediction models, with a least mean deviation of 7.06% and 0.8%. SHapley Additive exPlanations (SHAP) analysis revealed that Al2O3, followed by SiO2 showed the strongest positive correlation with viscosity, Na2O has the greatest negative contribution to melting temperature. Ternary viscosity and melting temperature distribution diagrams were constructed to visualize the prediction results. Insights from this study will highly benefit computer-aided design of mold fluxes with desired properties.
Melting and crystallization temperatures of poly(ε-caprolactone)(PCL) exposed to CO2 and N2 have been evaluated at pressures up to 125 bar using High Pressure Torsional Braid Analysis. It is shown ...that in contrast to CO2, exposure to high pressure N2 does not lead to a significant depression of Tm or Tc. Instead, these transition temperatures tend to increase in nitrogen, reflecting more of a hydrostatic pressure rather than a solvent effect. Another factor that may play a role is the fluid-induced crystallization which tends to increase the melting temperature. By conducting foaming at properly selected temperatures along the rigidity reduction paths which are scaled with respect to the melting temperatures in CO2 or N2, foams with low bulk foam densities of about 0.2 g/cm3 could be generated in CO2 at 100 bar and in N2 at 200 bar.
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•Tm and Tc of PCL in CO2 and in N2 have been determined using high pressure torsional braid analysis.•While Tm and Tc of PCL decrease in compressed CO2, they tend to increase in N2.•Knowing Tm and Tc allows for rational selections of foaming conditions in CO2 or N2.•Foams of PCL with low bulk densities around 0.2 g/cm3 have been generated in both CO2 and N2.
One of the most distinguished quantities that describes lipid main phase transition, i.e. the transition from the gel (Lβ(′)) to the fluid (Lα) phase, is its melting temperature (Tm). Because melting ...is accompanied by a large change in enthalpy the, Lβ(′) → Lα transition can be monitored by various calorimetric, structural and spectroscopic techniques and Tm should be the same regardless of the metric monitored or the technique employed. However, in the case of DPPE multilamellar aggregates there is a small but systematic deviation of Tm values determined by DSC and FTIR spectroscopy. The aim of this paper is to explain this discrepancy by combined UV/Vis spectroscopic and MD computational approach. Multivariate analysis performed on temperature-dependent UV/Vis spectra of DPPE suspensions demonstrated that at 55 ± 1 °C certain phenomenon causes a small but detectable change in suspension turbidity, whereas a dominant change in the latter is registered at 63.2 ± 0.4 °C that coincides with Tm value determined from DSC curve. If this effect should be ignored, the overall data give Tm value the same as FTIR spectra data (61.0 ± 0.4 °C). As the classical MD simulations suggest that about 10° below Tm certain undulations appear at the surface of DPPE bilayers, we concluded that certain discontinuities in curvature fluctuations arise at reported temperature which are to some extent coupled with lipid melting. Ultimately, such events and the associated changes in curvature affect Tm value measured by different techniques.
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•Temperature-dependent UV/Vis spectra of DPPE suspensions were acquired.•Multivariate analyses revealed two sigmoid transitions of DPPE spectral projections.•Low-temperature sigmoid transition originates from DPPE surface undulations.•MD simulations support the existence of surface undulations 10 °C below Tm of DPPE.•The origin of Tm systematic deviation obtained by different techniques is resolved.
The melting point is a fundamental property that is time-consuming to measure or compute, thus hindering high-throughput analyses of melting relations and phase diagrams over large sets of candidate ...compounds. To address this, we build a machine learning model, trained on a database of ∼10,000 compounds, that can predict the melting temperature in a fraction of a second. The model, made publicly available online, features graph neural network and residual neural network architectures. We demonstrate the model's usefulness in diverse applications. For the purpose of materials design and discovery, we show that it can quickly discover novel multicomponent materials with high melting points. These predictions are confirmed by density functional theory calculations and experimentally validated. In an application to planetary science and geology, we employ the model to analyze the melting temperatures of ∼4,800 minerals to uncover correlations relevant to the study of mineral evolution.
Organic osmolytes are known to play important role in stress protection by stabilizing macromolecules and suppressing harmful effects on functional activity. There is existence of several reports in ...the literature regarding their effects on structural, functional and thermodynamic aspects of many enzymes and the interaction parameters with proteins have been explored. Osmolytes are compatible with enzyme function and therefore, can be accumulated up to several millimolar concentrations. From the thermodynamic point of view, osmolyte raises mid-point of thermal denaturation (Tm) of proteins while having no significant effect on ΔGD° (free energy change at physiological condition). Unfavorable interaction with the peptide backbone due to preferential hydration is the major driving force for folding of unfolded polypeptide in presence of osmolyte. However, the thermodynamic basis of stress protection and origin of compatibility paradigm has been a debatable issue. In the present manuscript, we attempt to elaborate the origin of stress protection and compatibility paradigm of osmolytes based on the effect on thermodynamic stability of proteins. We also infer that protective effects of osmolytes on ΔGD° (of proteins) could also indicate its potential involvement in unfolded protein response and overall stress biology on macromolecular level.
Sliding graft copolymer (SGC) is a polyrotaxane (PR) composed of a poly(ethyelene glycol) (PEG) axle and α-cyclodextrins (α-CDs) substituted with polymer graft-chains. We have previously reported a ...sharp-endothermic phase transition of SGCs, which was expected due to the high mobility of graft chains by the mechanical linkage of PRs. To examine this hypothesis, SGCs with well-defined structures were prepared. PRs consisting of monoazidated α-CD and PEG were grafted with monomethoxy poly(ethylene glycos)s (mPEGs) via click chemistry. The SGC bearing shortest graft chains (mPEG750) did not exhibit endotherm, whereas those with side chains of mPEG2000 and mPEG4000 underwent endothermic phase transition. However, values of the transition temperatures and those of melting enthalpies were lower than those of unmodified mPEGs. Unlike our previous report, the SGCs synthesized here contained densely-packed α-CDs, which were capable of rotational movement but not translational movement. The endothermic peak observed for the present SGC is relatively broader than that observed for our previous SGC, which suggests that the mobility of α-CDs were critical to induce sharp-endothermic phase transition.
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•Sliding graft copolymers with different side chain lengths were synthesized.•The copolymer endotherm temperatures were lower than those of side chain polymers.•The limited motion of side chain grafted rings lowered the copolymer endotherms.
The optimal use of phase change materials (PCMs) in multilayer constructions in hot climates is taken into account in this study. PCMs could reduce energy use and improve indoor thermal comfort by ...being added to the building envelope. To achieve this, an optimization-based numerical model is created to predict the thermal behavior of a multilayer wall of the building in a hot environment. The finite element model is coupled with design exploration tools based on design of experiments methodology and the response surface technique to analyze the relationships between the influencing PCM parameters and the response variable, which is represented by the heat flow into the internal space. Optimization analysis is carried out to identify a set of PCM thermophysical and geometrical parameters which minimize the output variable. The set of input parameters that includes the PCM thickness and location as well as melting temperature and melting zone is implemented in the computational model for a simulation period of 10 days. The achieved results show a decrease in the maximum temperature at the internal wall compared to the original wall without PCM, with <20% of the heat entering the occupant area. The analysis demonstrates the potential utilization of PCMs as an approach to enhance the thermal characteristics of the building and decrease energy use in regions with high temperatures.
The epigenetics of methylated and unmethylated DCR1 and DCR2 (decoy receptors 1 and 2) are genes encoding membrane receptors that can bind to TRAIL causing TRAIL inhibition in the apoptotic pathway. ...Epigenetic detection of DCR1 and DCR2 was developed as a biomarker of breast cancer. One of the detection methods is using PCR. The most important step in the PCR process is the determination of the annealing temperature. This research performs Tm analysis using the insilico program from Neb, insilico, Thermofisher, and Promega and in vitro optimization. Methylated DCR1 can be amplified at annealing temperatures of 51.4°C, 52.4°C, 53.6°C, 54.7°C measuring about 600bp according to Tm analysis of insilico and promega. DCR1 could also be amplified at annealing temperatures of 50,1, 49, and 48.8 but the primers were also amplified at non-specific sites. Methylated DCR2 could be amplified at annealing temperatures of 48.8°C, 49°C and 50.1°C and a specific size of about 500 bp according to the Tm analysis of promega. Unmethylated DCR1 and DCR2 genes could not be amplified at the annealing temperature which were analyzed using Neb, insilico, promega, and thermofisher.
•PCM for cooling applications (active and passive systems).•Factors affecting PCM effectiveness.•Topology diagram summarizing PCM application.
Cooling demand in the building sector is growing ...rapidly; thermal energy storage systems using phase change materials (PCM) can be a very useful way to improve the building thermal performance. The right use of PCM in the envelope can minimize peak cooling loads, allow the use of smaller HVAC technical equipment for cooling, and has the capability to keep the indoor temperature within the comfort range due to smaller indoor temperature fluctuations. This article presents an overview of different PCM applications in buildings for reducing cooling loads under different climate conditions, and the factors affecting the successful and the effective use of the PCM. Many drawbacks have been found in PCM applications, mainly the intense impact of summer weather conditions over the PCM performance, which prohibits its complete solidification during night, and thus, limiting its effectiveness during the day. Proposed solutions are reviewed in this article. Finally, a topology diagram is presented to summarize the steps leading to an effective use of PCM in building applications.
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The specific effects of salts (strong electrolytes) on biomolecular properties have been investigated for more than a century. By contrast, the specific role of pH buffers (weak ...electrolytes and their salts) has usually been ignored. Here, specific buffer effects on DNA thermal stability were evaluated by measuring the melting curve of calf thymus DNA through UV–vis spectroscopy. The study was carried out using phosphate, Tris, citrate and cacodylate buffers at fixed pH 7.4 at concentrations varying systematically in the range 1–600 mM. DNA stability increases with buffer concentration and is influenced specifically by buffer type. To interpret empirical data, a theoretical model was applied with parameters quantifying the impact of buffer on the DNA backbone charge. Comparing the buffer effects via buffer ionic strength rather than buffer concentration, we find that the buffers stabilize DNA in the order Tris > cacodylate > phosphate > citrate.
