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The fluorescence signal levels produced by smart probes (SPs) largely depend on the type of fluorophore label used and the quenching efficiency of the quencher. However, there has been little emphasis on the effects of terminal location of the fluorophore and the modifications used to attach the fluorophore to the oligonucleotide chain. To this end, we have conducted a comparative study of the fluorescent signaling characteristics of six SPs consisting of three fluorophores: 6-FAM, ATTO488 and TAMRA, each of which was attached to either the 3′ end or the 5′ end of the oligonucleotide probe to make two SPs each. In each case, the fluorophore was paired with guanosine quenchers and we determined the fluorescence signaling characteristic of each SP by hybridizing it with the complementary target and measuring the fluorescence signal produced. Our results showed that the melting temperatures (Tm's) of each two SPs consisting of the same fluorophore were different before hybridization with targets but were similar once hybridized. We also found that each two SPs made of the same fluorophore gave different fluorescence signal levels. Our data also revealed a subtle correlation between Tm differences and fluorescence intensity differences for each pair of SPs consisting of the same fluorophore. We interpret the observed differences in Tm's and fluorescence signals in terms of possible structural differences in the linker moieties used for coupling the fluorophores to the 3′ and 5′ ends as well as possible differences in the efficiency of coupling the fluorophore during the probe synthesis. [ABSTRACT FROM AUTHOR]

T4 DNA ligase is a widely used ligase in many applications; yet in single nucleotide polymorphism analysis, it has been found generally lacking owing to its tendency to ligate mismatches quite efficiently. To address this lack of selectivity, we explored the effect of temperature on the selectivity of the ligase in discriminating single base pair mismatches at the 3′‐terminus of the ligating strand using short ligation probes (9‐mers). Remarkably, we observe outstanding selectivities when the assay temperature is increased to 7 °C to 13 °C above the dissociation temperature of the matched probe:target duplexes using commercially available enzyme at low concentration. Higher enzyme concentration shifts the temperature range to 13 °C to 19 °C above the probe:target dissociation temperatures. Finally, substituting the 5′‐phosphate terminus with an abasic nucleotide decreases the optimal temperature range to 7 °C to 10 °C above the matched probe:target duplex. We compare the temperature dependence of the T4 DNA ligase catalyzed ligation and a nonenzymatic ligation system to contrast the origin of their modes of selectivity. For the latter, temperatures above the probe:target duplex dissociation lead to lower ligation conversions even for the perfect matched system. This difference between the two ligation systems reveals the uniqueness of the T4 DNA ligase's ability to maintain excellent ligation yields for the matched system at elevated temperatures. Although our observations are consistent with previous mechanistic work on T4 DNA ligase, by mapping out the temperature dependence for different ligase concentrations and probe modifications, we identify simple strategies for introducing greater selectivity into SNP discrimination based on ligation yields. [ABSTRACT FROM AUTHOR]

Protein stability is a key factor in successful structural and biochemical research. However, the approaches for systematic comparison of protein stability are limited by sample consumption or compatibility with sample buffer components. Here we describe how miniaturized measurement of intrinsic tryptophan fluorescence (NanoDSF assay) in combination with a simplified description of protein unfolding can be used to interrogate the stability of a protein sample. We demonstrate that improved protein stability measures, such as apparent Gibbs free energy of unfolding, rather than melting temperature Tm, should be used to rank the results of thermostability screens. The assay is compatible with protein samples of any composition, including protein complexes and membrane proteins. Our data analysis software, MoltenProt, provides an easy and robust way to perform characterization of multiple samples. Potential applications of MoltenProt and NanoDSF include buffer and construct optimization for X‐ray crystallography and cryo‐electron microscopy, screening for small‐molecule binding partners and comparison of effects of point mutations. [ABSTRACT FROM AUTHOR]

Surface effect and crystal structure lead to formulating a theoretical model to study the influences of size on thermodynamic parameters, such as melting temperature, Debye temperature, melting entropy and specific heat capacity, of nanoparticles. The cohesive energy as a thermodynamic quantity was used to relate the ratio of surface area to volume of nanomaterial with thermodynamic properties which depend on size of the nanomaterial. In this contribution, Si and Au nanoparticles were considered to study due to their potential applications in science and technology. It was found that melting temperature, Debye temperature, melting entropy of nanoscale size material is decreased with decreasing the size up to their critical sizes. Whereas, the specific heat capacity tends to enhance with reduction in nanoparticle size. The present results for melting temperature, melting entropy and Debye temperature are compared with experimental and theoretical observations and adequate agreements are observed. [ABSTRACT FROM AUTHOR]

The stability of DNA molecules during viral or biotechnological encapsulation is a topic of active current research. We studied the thermal stability of double-stranded DNA molecules of different lengths in a confined space. Using a statistical model, we evaluate the melting profile of DNA molecules in two geometries: conical and cylindrical. Our results show that not only the confinement, but also the geometry of the confined space plays a prominent role in the stability and opening of the DNA duplex. We find that for more confined spaces, cylindrical confinement stabilizes the DNA, but for less confined spaces conical geometry stabilizes the DNA overall. We also analyse the interaction between DNA sequence and stability, and the evenness with which strand separation occurs. Cylindrical and conical geometries enable a better controlled tuning of the stability of DNA encapsulation and the efficiency of its eventual release, compared to spherical or quasi-spherical geometries. [ABSTRACT FROM AUTHOR]

Saturated fatty acid supplements commonly fed to dairy cows differ in their fatty acid (FA) profile. Some supplements with very high enrichments of palmitic acid (PA) or stearic acid (SA) have been reported to have low total-tract digestibility. Saturated FA have the potential to form crystalline structures at high purity that may affect digestibility. Differential scanning calorimetry (DSC) is a thermal technique commonly used in materials science to measure the change in heat flow as energy is absorbed or released from a sample during heating, and it was used to characterize a series of experimental and commercial fat supplements. Our hypothesis was that products with very high enrichment of either PA or SA would differ in thermal characteristics compared with those that include moderate levels of a second FA because of the formation of secondary crystalline structures, which may contribute to decreased digestibility. First, replicated runs demonstrated low variation in melting temperature (MT) and enthalpy (coefficient of variation <4%). The effect of physical form was evaluated by comparing an initial thermal cycle to a second, successive thermal cycle after samples had resolidified in the test pan. Melting temperature was slightly increased by 1.3°C by the second cycle compared with the first, but there was no change in enthalpy. Next, supplements with 98% SA, 98% PA, and an SA/PA (44%/55%) blend with undetectable levels of unsaturated FA were compared. Melting temperature of the SA/PA mixture was 61.2°C and similar to the expected MT of PA (62.9°C). However, the MT of the high-purity SA and PA were increased to 73.7°C and 67.8°C, respectively, and enthalpy increased by 12.5% compared with the SA/PA blend. An FA stock highly enriched in SA (>98%) had the highest MT, and one moderately enriched in PA (∼85%) that contained 10.1% unsaturated FA had the lowest enthalpy value of all FA supplements and experimental stocks that were characterized. Differential scanning calorimetry may be useful to screen and design supplements with improved physical properties that may be associated with digestibility. [ABSTRACT FROM AUTHOR]

This paper studies the effect of atoms number (N) of bulk Ag: N = 2 9 1 6 atoms (Ag 2 9 1 6 ), 4000 atoms (Ag 4 0 0 0 ), 5324 atoms (Ag 5 3 2 4) , 6912 atoms (Ag 6 9 1 2) at temperature T = 3 0 0 K, 400 K, 500 K, 600 K, 700 K, 800 K, 900 K, 1000 K on bulk Ag 5 3 2 4 and annealing time t = 200 ps on the structure and phase transition of Ag bulk by Molecular Dynamics (MD) method with Sutton–Chen (SC) pair interaction potential, periodic boundary conditions. The structural results are analyzed through the Radial Distribution Function (RDF), the total energy of the system ( E t o t) , the size (l) , the phase transition (determined by the relationship between E t o t and T), and combined with the Common Neighbors Analysis (CNA) method. The obtained results show that the first peak's position (r) of the RDF has negligible change value, r = 2. 7 8 Å, which is completely consistent with the experimental results. For bulk Ag, there are always four types of structure: FCC, HCP, BCC, Amor and glass transition temperature T g = 5 0 0 K. When decreasing the temperature, bulk Ag changes from liquid state to crystalline state, when increasing the annealing time at T g = 5 0 0 K, bulk Ag changes from amorphous phase to crystalline phase state, leading to the increase of FCC, HCP, BCC structures and the decrease of Amor structure. The obtained results will be used as guide for future experiments. [ABSTRACT FROM AUTHOR]

The Earth's core consists of iron as the major component. The melting point of iron at the inner core boundary constrains the thermal structure and solidification of the Earth's core. However, the current estimation of the melting temperature of iron under the core conditions has significant variations. Here, we measured the temperatures of iron shocked up to ~256 GPa using precise pyrometer and velocimeter diagnostics via a two‐stage light‐gas gun. Our results indicated that the melting temperatures of iron at the core‐mantle and inner core boundaries are 4300(250) and 5950(400) K, respectively. These temperatures are significantly lower than some previous shock experiments but are overall consistent with the recent results determined by fast X‐ray diffraction techniques, X‐ray absorption experiments in laser‐heated diamond anvil cells, and by ab initio computations. Our iron melting curve indicates a relatively small Clapeyron slope and supports thermal models for a young inner core. Plain Language Summary: Iron is the main constituent of the Earth's core, so its melting characteristics at high pressures are fundamentally crucial for understanding the thermal structure, solidification, and evolution of the core. We determined shock temperatures of melted iron up to ~256 GPa precisely by the use of a time‐resolved quasi‐spectral optical pyrometer. Our results are 1000–2000 K lower than those of some previous shock experiments. Our study reconciles the previous discrepancy in the melting temperatures of iron at pressures of 200–300 GPa and is consistent with theoretical calculations. We conclude that the melting temperature of iron at the Earth's inner core boundary is ~5950(400) K. The present study indicates a relatively gentle melting slope of iron and supports a young inner core age of ~0.565 Gyr inferred from paleomagnetic observations. Key Points: The melting temperatures of shocked iron are measured up to ~256 GPa by the time‐resolved pyrometerThe melting curves of iron at high pressures agree with each other in dynamic and static experiments and theoriesThe temperature at the inner core boundary is anchored to 5950(400) K based on the melting curve of iron [ABSTRACT FROM AUTHOR]

Global energy consumption is increasing every year, and, despite their many negative impacts, fossil fuels are a major source of energy, but their reserves are gradually depleting. One of the promising but underutilized resources is plant biomass (phytomass). The main problem of plant biomass combustion is the low melting temperature of ash, but there are also problems with corrosion of heat exchangers and clogging of heat-exchanging surfaces. This work is concerned with the production of straw pellets in order to increase the melting temperature of ash by adding an additive. The paper sludge contains substances that can increase the melting point of ash and was therefore added to the pellet samples. This additive was mixed with straw in ratios from 90:10, 80:20 and 70:30 (straw/paper sludge). The use of paper sludge showed positive effects on increasing the melting temperature of the ash samples. The deformation temperature of the ash has already risen from 1020 to 1260 °C after the addition of 10% sludge, which is comparable to wood pellets. [ABSTRACT FROM AUTHOR]

Zr-based bulk amorphous alloys which were heat-treated from 673 to 1073 K were investigated, and compressive fracture mechanisms related with improvement of mechanical properties were investigated by observing how the type, size and volume fraction of crystalline particles which is generated during the heat treatment affected the fracture mode. The Zr-based bulk amorphous alloys contained nano-sized crystalline particles showed excellent mechanical properties of compressive fracture strength over 2.0 GPa and compressive plastic strain of approximately 1%. The fracture modes of the alloys are changed depending on the heat treatment temperature and their microstructure. When the alloy is heat-treated at 673 K, the nano-sized Zr2Cu particles are generated in amorphous matrix. According to the observation of fractured specimens, in the alloy heat-treated at 673 K, the fine and elongated vein patterns were well developed. The heat treatment temperature increased above Tx, the Zr2Cu particles as well as complex crystalline particles are consist in the heat-treated alloy, which lead to the brittle fracture and the alloy show the low strength of 605 MPa. In the fractured surface of the alloy, large cleavage facets were evenly developed. When the heat treatment temperature up near Tm, the size of Zr2Cu and complex crystalline particles increased to approximately 1 μm and the volume fraction of complex crystalline particles increased up to 52.3%. As the size of crystalline particles change, the size of facet decreased similarly to the size of crystalline particles. Zr-based bulk amorphous alloys which were heat-treated from 673 to 1073 K were investigated, and compressive fracture mechanisms related with improvement of mechanical properties were investigated by observing how the type and size of crystalline particles which is generated during the heat treatment affected the fracture mode. The fracture modes of the alloys are changed depending on the heat treatment temperature and their microstructure. When the alloy is heattreated at 673 K, the nano-sized Zr2Cu particles are generated in amorphous matrix. According to the observation of fractured specimens, in the alloy heat-treated at 673 K, the fine and elongated vein patterns were well developed. The heat treatment temperature increased near Tg, the Zr2Cu particles as well as complex crystalline particles are consist in the heat-treated alloy, which lead to the brittle fracture and the alloy show the low strength of 605 MPa. In the fractured surface of the alloy, large cleavage facets were evenly developed. When the heat treatment temperature up near Tm, the size of Zr2Cu and complex crystalline particles increased to approximately 1 μm. [ABSTRACT FROM AUTHOR]

A fast and highly sensitive polymer nano-mechanical thermal analysis method for determining the melting temperature (Tm) of polymer microwires was proposed. In this method, a small-size, low-cost quartz tuning fork was used as a piezoelectric transducer to analyze the thermodynamics of polymer microwires at the nanogram level without changing its own properties. Due to the thin wire sample, which has a length of 1.2 mm and a diameter of ~5 µm, which is bridged across the prongs of the tuning fork, the nanogram-level sample greatly reduces the thermal equilibrium time for the measurement, resulting in a fast analysis for the melting temperature of the polymer sample. Compared with the traditional method, the analysis method based on the quartz enhanced conductivity spectrum (QECS) does not require annealing before measurement, which is an essential process for conventional thermal analysis to reduce the hardness, refine the grain, and eliminate the residual stress. In this work, the melting temperatures of three of the most commonly used polymers, namely polymers polymethyl methacrylate, high-density polyethylene, and disproportionated rosin, were obtained under the temperature from room temperature to >180 °C, proving the QECS method to be a useful tool for nano-mechanical thermal analysis. [ABSTRACT FROM AUTHOR]

The molecular dynamics (MD) simulations were applied to the melting transition of the BCC metal Fe using the modified embedded atom method (MEAM) potential proposed by Jin et al. [Appl. Phys. A120 (2015) 189], and the newly derived formulas were adopted to calculate the forces acting on atoms in the MD simulations. We first determined the structural and energetic properties of the effectively infinite solid with no boundaries, and then investigated the Fe samples with low-index surfaces, namely Fe(100), Fe(110), and Fe(111). The simulations show that as the temperature increases, the (111) surface firstly disorders, followed by the (100) surface, while the (110) surface remains stable up to the melting temperature. The disorder phenomenon diffuses from the surface to the entire block, and as the density of atoms on the surface decreases, the effect of the premelting phenomenon also increases, being most pronounced on Fe(111) which has the lowest surface density. This conclusion is in line with the behavior found for BCC metal V in the previous simulation study. [ABSTRACT FROM AUTHOR]

Several approaches to theoretical estimation of melting points for refractory metals and compounds by molecular dynamics calculations were analyzed and a new time-saving approach applicable to small two-phase ensembles and personal computers was suggested. The results of numerical calculations for melting points of refractory metals (Ta, W, Mo, V, Cr, Ti, Zr, Hf) and compounds (TiC, TiN, TiB2, TaC) well agree with respective tabulated values. [ABSTRACT FROM AUTHOR]

The results of a study of melting the commercial waxes in the composition of asphaltene-resin-paraffin deposits and for comparison of petroleum waxes in multicomponent solvents of various nature are presented. It was found that with an increase in the amount of the aliphatic component in the solvent, the content of the crystalline phase in paraffin wax rises. Patterns in the variation of paraffin melting temperatures depending on the content of the crystalline phase were revealed. Recommendations for choosing an effective solvent for removing deposits under conditions of permafrost influence are suggested. [ABSTRACT FROM AUTHOR]

The melting temperature of nanocrystals, an important property determining the thermal stability and catalytic activity of nanocatalysts, can be tailored by manipulating the size, dimensionality, interface, and composition. Although many studies have been performed on this topic, a comprehensive understanding of the melting temperature of nanocrystals remains deficient. To clarify the synergistic influences of the aforementioned parameters, a thermodynamic model is established from the perspective of the Gibbs free energy along with the size-dependent interface energy. The established model, containing no adjustable parameters, is valid for determining the melting temperature of nanocrystals (single-component nanocrystals or binary nanoalloys) of different sizes, dimensionalities, interface conditions, and compositions. Subsequently, the model calculations are compared with the corresponding experimental and simulation values. The observed consistency between the former and the latter confirms the validity and universality of the established model, which provides an opportunity to better understand the melting behaviors of nanocrystals. [ABSTRACT FROM AUTHOR]

In this work, a database containing thermochemical and structural information about 208 monotropic polymorphic forms has been created and analyzed. Most of the identified compounds (77 cases) have been found to have two polymorphs, 14 compounds have three forms and there are only three examples of systems with four polymorphs. The analysis of density distribution within the database has revealed that only 62 out of 114 metastable polymorphs (referred to as group I) obey the 'density rule' proposed by Burger and Ramberger [(1979), Mikrochim. Acta, 72, 259–271], while the remaining 45% of the monotropic systems (group II) violate the rule. A number of physicochemical, structural and molecular descriptors have been used to find and highlight the differences between group I and group II of the polymorphs. Group II is characterized (on average) by higher values of descriptors, which are responsible for conformational flexibility of molecules. An algorithm has been proposed for carrying out bivariate statistical analysis. It implies partitioning the database into structurally related clusters based on Tanimoto similarity coefficients and subsequent analysis of each cluster in terms of the number of hydrogen bonds per molecule. [ABSTRACT FROM AUTHOR]

Many genetic researches now relies on the study of variants in genetic material through different, diverse of universal Polymerase Chain Reaction (PCR) methods. In that context, we are putting a highlighted on the most important fundamental aspects of PCR technology, which help researchers to clarify and reduce the majority problems and difficulties may face them in the laboratory work of any kind of PCR technology in general. [ABSTRACT FROM AUTHOR]

In this study, the folding of G-quadruplex (G4) from the telomeric DNA sequences having loop nucleobases of different chemical natures, numbers, and arrangements in 10 mM and 100 mM KCl salt conditions mimicking the cancerous and normal KCl salt microenvironments have been investigated. The data suggest that the structure and stability of the G4 are highly dependent on the KCl salt concentration. In general, the conformational flexibility of the folded G4 is higher in KCl salt relevant to cancer than in the normal case for any loop arrangements with the same number of nucleobases. The stability of the G4 decreases with the increase in the number of loop nucleobases for both salt conditions. However, the decrease in the stability of G4 having adenine in the loop region is significantly higher than the case of thymine, particularly more prominent in the KCl salt relevant to the cancer. The topology of the folded G4 and its stability also depend delicately on the permutation of the nucleobases in the loop and the salt concentrations for a particular sequence. The findings indicate that the structure and stability of G4 are noticeably different in KCl salt relevant to physiological and cancer conditions. [ABSTRACT FROM AUTHOR]

Given that the decomposition temperature is close to the melting point, polyvinyl alcohol (PVA) fails thermoplastic processing. Developing a suitable plasticizer-enhancing system to reduce melting point or increase the decomposition temperature, resulting in generating a temperature window of thermoplastic processing is an urgent research topic in practical processing applications. In this work, triethyl citrate (TEC) (or tributyl citrate (TBC)), as a green plasticizer, was successfully introduced in the PVA matrix by rational and scientific means. To systematically explore the effects of plasticizers on melting point and mechanical properties of the PVA, distinguishing from traditional plasticizer-adding means, the optimized plasticizer was added to the PVA precursor (i.e., polyvinyl acetate (PVAc)), generating a highly effective blend at upon molecular level, which can achieve a uniform phase mixture of plasticizer molecules in PVA after alcoholysis. In this case, small molecular plasticizers participate in the formation of intermolecular hydrogen bonds between PVA molecules, thus forming abundant effective energy dissipation sites. As a result, thus-obtained A-PVA/TEC10 exhibited an elongation at break of 385.3% and toughness of 154.4 MPa, which are 2.87 times and 1.75 times than those of unplasticized PVA, respectively. Also, the elongation at break and toughness of A-PVA/TEC10 are far superior to those of PVA that are prepared by directly blending way. Most importantly, along with the augmentation of the TEC plasticizer in the PVA system, the melting temperature of plasticized PVA achieved after the alcoholysis reaction of PVAc/TEC10 decreased significantly, and slightly increased in decomposition temperature. This work offers a valuable and justified plasticizing strategy for the processability of PVA materials. [Display omitted] • PVA matrix with wide thermoplastic processing window was successfully synthesized by a novel plasticizer addition method. • Two efficient green plasticizers contributes to toughening and strengthening mechanical properties of PVA. • Optimized film prepared from PVA-plasticized with outstanding properties was developed. • Unprecedented tensile strain, excellent toughness and adequate tensile strength were favorably balanced. [ABSTRACT FROM AUTHOR]

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. [Display omitted] • 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. [ABSTRACT FROM AUTHOR]

In cavities differentially heated at the sides and subjected to mechanical vibration, the natural convection incoming from buoyancy effects is not the only factor affecting the flow dynamic and heat transfer. The current work aims to address vibrational convection in a square chamber filled with a Nano-Encapsulated Phase Change Material (NEPCM) suspension. The non-dimensional equations of fluid and heat flows in the cavity are developed and solved numerically. The gravity term in the momentum equation is modified to include the effect of vibration. It is shown that the vibrational Rayleigh number has the most effect on the convective heat transfer, followed by the conductivity of the NEPCM suspension. Increasing the vibrational Rayleigh number from 10 3 to 10 7 leads to up to 3 times rise in the time-averaged Nusselt number. The NEPCM concentration has a moderate influence, as around 12% increase in the time-averaged Nusselt number is found when a 5% volume fraction of particles is employed. An increase in the Stefan number from 0.2 to 0.8 is associated with a 6.1% reduction in the time-averaged Nusselt number. Additionally, the peak heat transfer is achieved at the melting point of 0.5, with a 6.5% increase compared to the melting temperature of 0.1. [ABSTRACT FROM AUTHOR]

• This work aims to provide a comprehensive comparison of the various melting methods in terms of their accuracy and efficiency. • The impact of the atomic numbers, heating and cooling rates, crystal defects, and nucleation processes for T m is discussed. • The driving degree of the different proportions of a solid and the number of solid–liquid interfaces on melting behaviors are explored. • To further enhance the accuracy of T m calculations, we propose a new approach termed the modified two–phase method. Machine learning approaches have been extensively applied to improve the accuracy and reliability of potentials, addressing inherent limitations in molecular dynamics (MD) simulations. Notably, the precise determination of the melting temperature (T m) relies on MD simulations, necessitating a comprehensive review of available melting models. This study aims to present a thorough comparison of various melting methods, including the single–phase method, hysteresis method, Z method, modified Z method, void method, modified void method, two–phase method, and sandwich method, considering both accuracy and efficiency. These melting models are systematically categorized into three groups: perfect crystals, crystal defects, and solid–liquid interfaces. The impact of factors such as atomic numbers, heating and cooling rates, crystal defects, and nucleation processes on T m is discussed. Additionally, the temperatures corresponding to the superheating limit and the amorphous transition induced by heating and cooling rates during melting and crystallization processes are analyzed. Furthermore, the study explores the impact of different proportions of solid and the number of solid–liquid interfaces on melting behaviors. To further enhance the accuracy of T m calculations, we propose a new approach termed the modified two–phase method, integrating the void method and two–phase method to account for crystal defects and solid–liquid coexistence, respectively. [ABSTRACT FROM AUTHOR]

The melting temperature, a crucial material property, is particularly challenging to measure accurately for inorganic crystals. The data-driven approach emerges as a potential solution, although its effectiveness is hindered by the limitation of available data. To counter this challenge, we implement transfer learning, leveraging a vast computational database of atomization energy. We first pre-train a geometric-information-enhanced crystal graph neural network (GeoCGNN) using atomization energies of approximately 36,000 materials that are computed by the density functional theory. Subsequently, the pre-trained model is fine-tuned using melting temperatures measured for 799 crystals, encompassing 83 elements, ranging from unary to quaternary systems. This transfer learning strategy decreases the root mean square error from 407 to 218 K, attesting to a marked improvement in prediction accuracy. Furthermore, transfer learning significantly mitigates error variability across unary, binary, and ternary (or higher-order) systems, thereby enhancing the reliability of predictions across a broader range of crystals. We also show that transfer learning allows effective task adaptation by leveraging representation learned from pre-training. Therefore, it can achieve better prediction performance even with a limited number of data for predicting melting points. [Display omitted] • Transfer learning is employed to predict melting points for inorganic crystals. • Crystal graph neural network is utilized to deal with a broad class of crystals. • By applying transfer learning, the accuracy of predictions is improved by 46%. • Improvements in each crystal class rely on physical relationship to pre-training set. • Effective task adaptation by transfer learning gives high accuracy for limited data. [ABSTRACT FROM AUTHOR]

The aim of this work was to develop a new, automated method for the detection of solid-liquid phase transitions in the presence of high-pressure carbon dioxide. This is allowed because of the dissolution of the medium in the sample during the solid-liquid-gas equilibrium measurement. The pressure of an empty reference cell and one containing a solid sample is compared by a differential pressure transmitter. A gradual heating program is conducted after their equal pressurization. The solid-liquid transition of the sample is marked by a sharp decrease in the pressure of the sample holder (compared to the reference cell). A processing algorithm for the recorded time – temperature – pressure-difference data was implemented, to determine the melting temperature range accurately and automatically. The apparatus was validated with racemic ibuprofen and benzoic acid, and provides a new, objective, and easy-to-automate alternative to determine the melting temperature in high-pressure carbon dioxide. [Display omitted] • A new device for investigating solid-liquid-gas equilibrium was constructed. • Pressure difference measurement offers sensitive detection of the phase transition. • A completely automated algorithm for the data evaluation was implemented. • The apparatus was validated with ibuprofen and benzoic acid under CO2 pressure. [ABSTRACT FROM AUTHOR]

The flame brazing of H62 brass using a novel, low-silver Cu-P brazing filler metal was investigated in this study. The effect of the addition of a trace amount of Sn on the microstructure and properties of Cu-7P-1Ag filler metals was analyzed by means of X-ray diffractometer, scanning electron microscopy and energy dispersive spectrometer. The addition of trace Sn led to a decrease in the solidus and liquidus temperatures of Cu-7P-1Ag filler metals. Meanwhile, the spreading performance of the filler metals on a H62 brass substrate was improved. The microstructure of the low-silver, Cu-P brazing filler metal was mainly composed of α-Ag solid solution, α-Cu solid solution and Cu3P; an increase of Sn content led to the transformation of the microstructure of the joints from a block to a lamellar structure. When the Sn content was 0.5 wt. %, the shear strength of the joint at room temperature reached 348 MPa, and the fracture morphologies changed from a cleavage to a quasi-cleavage structure.

The novel low-silver 12AgCuZnSn filler metals containing In and Pr were used for flame brazing of copper and 304 stainless steel in this study. The effects of In and Pr content on the melting temperature, wettability, mechanical properties and microstructure of 12AgCuZnSn filler metal were analyzed. The results indicate that the solidus and liquidus temperatures of filler metals decrease with the addition of In. Trace amounts of Pr have little impact on the melting temperature of the low-silver filler metals. In addition, the spreading area of filler metals on copper and 304 stainless steel is improved. The highest shear strength of brazed joint is 427 MPa when the content of In and Pr are 2 wt.% and 0.15 wt.%, respectively. Moreover, it is observed that the trace amount of Pr significantly refines the microstructure of brazed joint matrix. A bright Pr3Cu4Sn4 phase is found in filler metal and brazing seam when the contents of In and Pr are 5 wt.% and 0.5 wt.%, respectively.

The melting and crystallization temperatures of platinum nanoclusters have been found by using results of molecular dynamics modeling, obtained employing two different computer programs and different interatomic interaction potentials. The size dependences found in computer experiments are compared with molecular dynamics data of other authors and with estimations of the melting temperature using Thomson’s formula.

The melting of zigzag, armchair and chiral single walled boron nitride nanotubes (SWBNs) investigated using molecular dynamics (MD) simulation based on Tersoff-like many body potential. The MD simulation has been employed in the constant pressure, constant temperature (NPT) ensemble. The temperature and pressure of the system were controlled by Nose-Hoover thermostat and Berendsen barostat, respectively. We have computed the variation of the melting temperature with the radius of BN nanotube. The results show that the melting temperature of nanotubes increase with increasing in the size of radii, but this dependence is not the same for the various chiral angle of nanotubes. The relation of the melting point with radius for three types of nanotubes i.e. zigzag, armchair and chiral obtained. Moreover, our results show that the melting temperature of nanotubes approach a constant value at larger radii.

The effects of MgO content on the viscosity and melting behaviors of CaO-Al2O3-MgO-FexO-SiO2-K2O slags were studied. The slag samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) to identify precipitated phases during the cooling process. Meanwhile, theoretical calculations on the viscosities, solidus/liquidus temperatures as well as quantities of various precipitated phases from the slag system were also carried out by using the FactSage software, which were compared with the experimental results. The results indicate that the addition of MgO in slag could cause the increase of melting temperature. The relation between viscosities and temperature presents a breakpoint where the viscosity has a rapid rise, and above this transition temperature, MgO content has little effect on the viscosity. The transition temperature increases with the increasing of MgO content. In the process of slag cooling, the crystalline phases are mainly composed of olivine and spinel. From the calculation results, it could be found that the addition of MgO enhances the precipitates of olivine, which makes the viscosity increase suddenly.

The relevance of the discussed issue is caused by the need to advance thermal spray technology and the methods for determining the process best performance. The main aim of the study is to determine thermal fields and adhesion temperature conditions in the model «liquid-alloy droplet - substrate». The methods used in the study: the mathematical modeling for thermal fields and adhesion temperature conditions in the model «liquid - alloy droplet - substrate»; experimental validation of the results calculated with the proposed model. The results. The paper introduces the method for determining thermal fields in the model «liquid-alloy droplet - substrate» based on equalization of temperatures of fixed identical small size neighboring cubic volumes. The method is based on the concept that non-steady process of thermal heating approaches to steady-state process as time and dimensional gaps are reduced. The provided method is free from using differential equations. The calculation of non-steady thermal field is based on thermal transmission equation (algebraic equations). Adhesion temperature conditions for a droplet impacting on a solid surface are obtained. The thermal condition of adhesion is based on substrate melting. Partial adhesion corresponds to melting of the part of substrate surface, total adhesion corresponds to melting of the whole substrate surface. The proposed thermal adhesion condition is valid in case of lack of intermetallic compounds formation between spat and substrate materials. The calculated results are in accordance with the experimental data.

The thermal stability of DNA immobilized on a solid surface is one of the factors that affects the efficiency of solid-phase amplification (SP-PCR). Although variable temperature amplification ensures high specificity of the reaction by precisely controlling temperature changes, excessively high temperatures during denaturation can negatively affect DNA stability. Formamide (FA) enables DNA denaturation at lower temperatures, showing potential for SP-PCR. Research on FA's impacts on DNA microarrays is still limited, necessitating further optimization in exploring the characteristics of FA in SP-PCR according to particular application needs. We immobilized DNA on a chip using a crosslinker and generated DNA microarrays through bridge amplification based on FA denaturation on our automated reaction device. We optimized the denaturation and hybridization parameters of FA, achieving a maximum cluster density of 2.83 × 10 4 colonies/mm 2 . Compared to high-temperature denaturation, FA denaturation required a lower template concentration and milder reaction conditions and produced higher cluster density, demonstrating that FA effectively improves hybridization rates on surfaces. Regarding the immobilized DNA stability, the FA group exhibited a 45% loss of DNA, resulting in a 15% higher DNA retention rate compared to the high-temperature group, indicating that FA can better maintain DNA stability. Our study suggests that using FA improves the immobilized DNA stability and amplification efficiency in SP-PCR.

The Gd 2 O 3 - GdSrFeO 4 pseudo-binary phase diagram is presented for the first time. The liquidus and eutectic temperatures, metatectic points of the Gd 2 O 3 transformations in the Gd 2 O 3 - GdSrFeO 4 section were defined using the Schröder-Le Chatelier equation, neglecting the effect of the isobaric heat capacity. The calculations were based on experimental data on the melting points of the end-members and the eutectic composition. From the results of phase relationships studies (subsolidus and high temperature region including literature data as well) and the above approach the Gd2O3-GdSrFeO4 pseudo-binary phase diagram in the temperature range 1400-2410 °C in air was constructed. It was shown that GdSrFeO 4 of the K 2 NiF 4 - type is stable from 1100°С to a congruent melting temperature of 1560°С in air. The Gd 2 O 3 - GdSrFeO 4 system is eutectic with no intermediate compounds., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

In this study, we establish an efficient enzymatic approach for producing novel inotodiyl-oleates (IOs) from pure inotodiol and oleic acid to improve the properties of inotodiol. For the esterification between inotodiol and oleic acid, CALA and n-hexane were the optimal biocatalyst and solvents for forming IOs with 80.17% conversion yield. These IOs comprised two distinct monoesters, the C3 or C22 ester forms of inotodiol. Intriguingly, no diesters were detected. The IOs had a melting point of 53.48 °C, much lower than that of inotodiol (192.06 °C). The in vitro digestion rate of IOs (25-28%) was significantly (p < 0.05) lower than that of cholesteryl-oleate (60%). Additionally, IOs exhibited much lower in vivo absorption than inotodiol when orally administered using different formulations (p < 0.05). The results indicated that IOs were resistant to enzymatic digestion in the small intestine, which could be advantageous in targeting the large intestine for disease treatments., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

An increasing number of antisense oligonucleotides (ASOs) have been approved for clinical use. However, improvements of both efficacy and safety in the central nervous system (CNS) are crucial for the treatment with CNS diseases. We aimed to overcome the crucial issues by our development of various gapmer ASOs with a novel nucleoside derivative including a 2',4'-BNA/LNA with 9-(aminoethoxy)phenoxazine (BNAP-AEO). The various gapmer ASOs with BNAP-AEO were evaluated for thermal stability, in vitro and in vivo efficacy, and acute CNS toxicity. Thermal stability analysis of the duplexes with their complementary RNAs showed that ASOs with BNAP-AEO had a higher binding affinity than those without BNAP-AEO. In vitro assays, when transfected into neuroblastoma cell lines, demonstrated that ASOs with BNAP-AEO, had a more efficient gene silencing effect than those without BNAP-AEO. In vivo assays, involving intracerebroventricular injections into mice, revealed ASOs with BNAP-AEO potently suppressed gene expression in the brain. Surprisingly, the acute CNS toxicity in mice, as assessed through open field tests and scoring systems, was significantly lower for ASOs with BNAP-AEO than for those without BNAP-AEO. This study underscores the efficient gene-silencing effect and low acute CNS toxicity of ASOs incorporating BNAP-AEO, indicating the potential for future therapeutic applications., Competing Interests: T.Yokota collaborates with Takeda Pharmaceuticals Co., Ltd., Daiichi Sankyo Co., Ltd., Rena Therapeutics Co., Ltd., Toray Industries Co., Ltd., Eisai Co., Ltd., and Sumitomo Pharma Co., Ltd., and serves as the academic adviser for Rena Therapeutics, Inc., and Braizon Therapeutics, Inc. A provisional patent application (PCT/JP2023/024244) describing the work and chemistry used in this study has been submitted (authors: T.Yokota, K.Y., T.M., S.O., and O.N.)., (© 2024 The Authors.)

Mastering selective molecule trafficking across human cell membranes poses a formidable challenge in healthcare biotechnology while offering the prospect of breakthroughs in drug delivery, gene therapy, and diagnostic imaging. The cholera toxin B-subunit (CTB) has the potential to be a useful cargo transporter for these applications. CTB is a robust protein that is amenable to reengineering for diverse applications; however, protein redesign has mostly focused on modifications of the N- and C-termini of the protein. Exploiting the full power of rational redesign requires a detailed understanding of the contributions of the surface residues to protein stability and binding activity. Here, we employed Rosetta-based computational saturation scans on 58 surface residues of CTB, including the GM1 binding site, to analyze both ligand-bound and ligand-free structures to decipher mutational effects on protein stability and GM1 affinity. Complimentary experimental results from differential scanning fluorimetry and isothermal titration calorimetry provided melting temperatures and GM1 binding affinities for 40 alanine mutants among these positions. The results showed that CTB can accommodate diverse mutations while maintaining its stability and ligand binding affinity. These mutations could potentially allow modification of the oligosaccharide binding specificity to change its cellular targeting, alter the B-subunit intracellular routing, or impact its shelf-life and in vivo half-life through changes to protein stability. We anticipate that the mutational space maps presented here will serve as a cornerstone for future CTB redesigns, paving the way for the development of innovative biotechnological tools.

Background: The accurate and expeditious detection of SARS-CoV-2 mutations is critical for monitoring viral evolution, assessing its impact on transmission, virulence, and vaccine efficacy, and formulating public health interventions. In this study, a detection system utilizing micro temperature gradient gel electrophoresis (μTGGE) was developed for the identification of the D614 and G614 variants of the SARS-CoV-2 spike protein., Methods: The in vitro synthesized D614 and G614 gene fragments of the SARS-CoV-2 spike protein were amplified via polymerase chain reaction and subjected to μTGGE analysis., Results: The migration patterns exhibited by the D614 and G614 variants on the polyacrylamide gel were distinctly dissimilar and readily discernible by μTGGE. In particular, the mid-melting pattern of D614 was shorter than that of G614., Conclusions: Our results demonstrate the capability of μTGGE for the rapid, precise, and cost-effective detection of SARS-CoV-2 spike protein D614 and G614 variants without the need for sequencing. Therefore, this approach holds considerable potential for use in point-of-care mutation assays for SARS-CoV-2 and other pathogens., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

The effect of different In contents on the melting characteristics, mechanical properties, and microstructure of 12Ag–Cu–Zn–Sn filler metal was investigated in this paper, and flame brazing of 304 stainless steel and copper plates was done using the 12Ag–Cu–Zn–Sn–xIn filler metal. The results indicate that adding appropriate amount of In can evidently decrease the solidus and liquidus temperatures and improve the wettability of the low silver based filler metals. In addition, the shear strength of 304 stainless steel and copper plates joint brazed by 12Ag–Cu–Zn–Sn–1In are satisfactory due to the solution strength effect, and scanning electron microscopy examination of the braze-zone revealed that more relatively sound joints were obtained when brazing was done with 12Ag–Cu–Zn–Sn–xIn filler metal than with Indium free one; its performance is comparable to that of the joint brazed with the 20Ag–Cu–Zn–Sn filler metal, having a remarkable silver-saving effect.

Magnetic pulse welding (MPW) is a promising joining technology for the large-scale production of dissimilar metallic joints. Although the heat input is comparatively low, the temporary occurrence of high temperatures in the joining gap was found to play an important role during the joint formation. It is possible that the melting or even the boiling temperature of the involved materials will be exceeded, and fusion welding will occur. The purpose of this study is to investigate the influence of target materials with different thermal properties on the joint formation and weld seam characteristic. Therefore, MPW between steel targets and aluminum flyers was performed with and without copper coatings on steel. The lower melting temperature of copper compared to steel had no significant effect on the appearance of the mixed zones in the interface and the amount of molten target material or aluminum, respectively. Nevertheless, the comparison of the higher impact energies showed, that the copper interlayer can lead to a decrease in the weld length or a degradation of the weld quality due to an extended intermetallic phase formation or cracks. This result is important for the parameter adjustment of magnetic pulse welding processes.

Al2O3 is one of the main component in blast furnace (BF) slag, which the reaction mechanism influence on the metallurgical performance directly in the process of the slag forming. In the paper, ΔGf θ was used to analyzed the slag formation reaction process of the Al2O3,at the same time, the phase diagram and activity were calculated by Fact- Sage with CaO - MgO - SiO2 - Al2O3 slag system, it can be found that the complete liquid phase region temperature is about 1 500 °C and the content of the Al2O3 is 11%. Activity of CaO is stronger than the others, from which the liquid phase can be formed easily in the high temperature, meantime the reaction energy barrier between CaO and SiO2 is lower and stabilization of the product is better. By the high temperature experiment, a lot of Ca2Al2SiO7 was separated out with the high content of Al2O3 and slag basicity, as a result, the transformation of the solid phase to the liquid phase was effected by the constantly increasing the content of Al2O3. [ABSTRACT FROM AUTHOR]

Recombinant adeno-associated virus (AAV) vectors have evolved as the most promising technology for gene therapy due to their good safety profile, high transduction efficacy, and long-term gene expression in non-dividing cells. AAV-based gene therapy holds great promise for treating genetic disorders like inherited blindness, muscular atrophy, or bleeding disorders. Multiple naturally occurring and engineered AAV serotypes exist, which differ in capsid sequence and as a consequence in cellular tropism. Individual AAV capsids differ in thermal stability and have a characteristic melting temperature (T m), which enables serotype-specific discrimination of AAV vectors. Differential scanning fluorimetry (DSF) combined with a dye-like SYPRO Orange (SO-DSF), which binds to hydrophobic regions of unfolded proteins, has been successfully applied to determine the T m of AAV capsids. Here, we present DSF measurement of intrinsic fluorescence signal (iDSF) as a simple alternative method for determination of AAV capsid T m. The study demonstrates that DSF measurement of intrinsic fluorescence signal is a simple, accurate, and rapid alternative to SO-DSF, which enables characterization of AAV capsid stability with excellent precision and without the need of SO or any other dye. [ABSTRACT FROM AUTHOR]