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Protein science 30(1), 201 - 217 (2021). doi:10.1002/pro.3986, 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 T$_m$, 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., Published by Protein Society, Bethesda, Md.

Improvements of melting resistance and quality by modification of pork‐skin jelly through enzymatic cross‐linking were studied, and the mechanism of quality improvement was discussed in this work. Gel strength, springiness and chewiness of modified gel increased significantly (P

Based on the review of the literature results the database of the fusion temperatures of two-component molecular crystals (1947 co-crystals) and individual components thereof was built up. To improve the design of co-crystals with predictable melting temperatures, the correlation equations connecting co-crystals and individual components melting points were deduced. These correlations were discovered for 18 co-crystals of different stoichiometric compositions. The correlation coefficients were analysed, and the conclusions about the main/determinative and slave components of a co-crystal were made. The comparative analysis of the melting points of co-crystals composed from the same components but with different stoichiometry showed a co-crystal melting temperature growth when increasing the content of a high-melting component. The differences in the melting temperatures were determined and discussed for the following: (a) monotropic polymorphic forms, (b) two-component crystals with the same composition and different stoichiometry, and (c) two-component crystals based on racemates and enantiomers. The database analysis revealed the active pharmaceutical ingredients (APIs) and co-formers (CFs) more particularly used for co-crystal design. The approach based on an efficacy parameter allowing the prediction of co-crystals with melting points lower than those of individual compounds was developed.

The combination of supramolecular aggregation of collagen model peptides with reversible covalent end‐capping of the formed triple helix in a single experimental set‐up yielded minicollagens, which were characterized by a single melting temperature. In spite of the numerous possible reaction intermediates, a specific synthetic collagen with a leading, middle and trailing strand is formed in a highly cooperative self‐assembly process., Supramolecular assembly of collagen model peptides was combined with reversible covalent end‐capping. The quantitative formation of a single‐capped triple helix was analysed via NMR spectroscopy. This leads to a novel class of end‐capped collagen model peptides with less effort.

Radiation cross-linked ultra-high-molecular-weight polyethylenes (UHMWPEs) are clinically used extensively in total joint arthroplasty due to their high wear resistance. Peroxide cross-linking of UHMWPE has been proposed to achieve this high level of wear resistance by simultaneously consolidating and cross-linking in the melt state. High temperature melting of uncross-linked and cross-linked UHMWPEs have further shown to improve the toughness. Here, we report on the wear and mechanical properties of a peroxide cross-linked and high-temperature melted UHMWPE as a function of vitamin E concentration for oxidative stabilization, peroxide concentration for cross-linking and high temperature melting temperature for toughness improvement. This method, combining consolidation and cross-linking in one step, presents an opportunity to manufacture highly wear and oxidation-resistant joint implant-bearing surfaces with much improved toughness. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2182-2188, 2019.

We present a theory of pressure-dependent melting temperature to describe the physical fact that both cooling and pressurization can cause the solidification of liquid metal. Based on the Force-Hea...

Irvingia gabonensis kernels are a promising oleiferous source. Their total lipid content was 72.3%. C14:0 and C12:0 represented the most abundant fatty acids. Triacylglycerols with ECN 32 and 46–48 were identified for the first time by HPLC‐DAD‐ESI‐MSⁿ. Comprehensive GC‐FID and GC‐MS analyses revealed novel insights into minor lipids like phytosterols and tocochromanols. Among the latter, γ‐tocopherol was found to be the major vitamer. β‐Sitosterol and stigmasterol were the prevailing phytosterols in the kernel fat. The high saturation level of the fat resulted in a sharp differential scanning calorimetry melting curve with a high melting temperature of 42.1 °C. The fat remained solid over a wide temperature range and still contained 66.6% solid fats at 35 °C. Consequently, kernels of the African mango provide a viable source for the recovery of solid fats applicable in the food industry as sustainable alternatives to replace palm‐based fats or hardened vegetable oils.

Embedding of tissue samples that maintains a desired orientation is critical for preparing sections suitable for diagnosis and study objectives. Methods to prepare tissue sections include: (i) paraffin embedding or snap-freezing followed by microtome or cryostat sectioning; and (ii) agarose embedding followed by cutting on a vibrating microslicer. Although these methods are useful for routine laboratory work, preparation of small and fragile tissues such as mouse organs, small human biopsy samples, and cultured floating spheres is difficult and requires special skills. In particular, tissue specimen orientation can be lost during embedding in molds and subsequent sectioning. Here, we developed a method using low melting temperature (LM) gelatin either alone or mixed with agarose to preliminarily embed collected tissues that are either prefixed or unfixed, followed by conventional fixation, paraffin embedding, freezing, and sectioning. The advantage of the method is that the LM gelatin and its mixture with agarose can be handled at room temperature but quickly hardens at 4°C, which allows embedding, trimming, and arranging of small and fragile tissues in a desired orientation and are compatible with traditional stainings. Thus, this method can have various laboratory applications and can be modified according to the needs of each laboratory.

Poly(cyclohexane-1,4-dimethylene cyclohexane-1,4-dicarboxylate) has been prepared by solid-state polymerization using 1,4-cyclohexanedicarboxylic acid or its di-methylester and 1,4-cyclohexanedimethanol as monomers. The process consists in a first step in which a prepolymer with high crystallinity is prepared by melt polycondensation and then submitted to solid-state polymerization (SSP) at a temperature below the melting temperature of the polymer. The use of the solid state process permits to minimize the isomerization from the trans to the cis form in the polymer chain and therefore a polyester with higher crystallinity and melting temperature, compared to those synthesized by the traditional polycondensation routes, can be obtained. For this reason, the SSP process allows to obtain materials with thermo-mechanical properties that cannot be achieved using the standard polycondensation method. Moreover, the process does not involve a complex multi-step temperature ramp as in the case of the polycondensation process.

A combination method of real-time PCR and high-resolution melting (HRM) analysis for the rapid detection and specific classification of six pathogenic Cronobacter species based on gene cgcA was developed. HRM profiles with distinct Tm (melting temperature) peaks were consistently obtained with each species, represented by a single peak ranging from 86.02 to 86.80 °C. The detection limit ranged from 0.1 to 1 pg per reaction. Desiccated Cronobacter sakazakii and Cronobacter muytjensii of 2 cfu/25 g were successfully detected after 4-week storage at room temperature. The newly developed method provided a molecular tool for direct detection and simultaneous identification of pathogenic Cronobacter species in powdered infant formulae.

Protein design advancements have led to biotechnological strategies based on more stable and more specific structures. Herein we present a 6-residue sequence (HPATGK) that acts as a stable structure-nucleating turn at physiological and higher pH but is notably unfavorable for chain direction reversal at low pH. When placed into the turn of a β-sheet, this leads to a pH switch of folding. Using a standard 3-stranded β-sheet model, the WW domain, it was found that the pH switch sequence insertion caused minimal change at pH 8 but a ca. 50 °C drop in the melting temperature (Tm) was observed at pH 2.5: ΔΔGF ≥11.3 kJ mol−1. Using the strategies demonstrated in this article, the redesign of β-sheets to contain a global, or local, pH-dependent conformational switch should be possible.

Monitoring the fluorescence of proteins, particularly the fluorescence of intrinsic tryptophan residues, is a popular method often used in the analysis of unfolding transitions (induced by temperature, chemical denaturant, and pH) in proteins. The tryptophan fluorescence provides several suitable parameters, such as steady-state fluorescence intensity, apparent quantum yield, mean fluorescence lifetime, position of emission maximum that are often utilized for the observation of the conformational/unfolding transitions of proteins. In addition, the fluorescence intensities ratio at different wavelengths (usually at 330 nm and 350 nm) is becoming an increasingly popular parameter for the evaluation of thermal transitions. We show that, under certain conditions, the use of this parameter for the analysis of unfolding transitions leads to the incorrect determination of thermodynamic parameters characterizing unfolding transitions in proteins (e.g., melting temperature) and, hence, can compromise the hit identification during high-throughput drug screening campaigns.

We used the molecular modeling program Rosetta to identify clusters of amino acid substitutions in antibody fragments (scFvs and scAbs) that improve global protein stability and resistance to thermal deactivation. Using this methodology, we increased the melting temperature (T(m)) and resistance to heat treatment of an antibody fragment that binds to the Clostridium botulinum hemagglutinin protein (anti-HA33). Two designed antibody fragment variants with two amino acid replacement clusters, designed to stabilize local regions, were shown to have both higher T(m) compared to the parental scFv and importantly, to retain full antigen binding activity after 2 hours of incubation at 70 °C. The crystal structure of one thermostabilized scFv variants was solved at 1.6 Å and shown to be in close agreement with the RosettaAntibody model prediction.

In this contribution, a new model to predict the thermodynamic properties, namely enthalpy of fusion (ΔHf) and melting temperature (Tm), of pure triglycerides (TAGs) is presented. Different contributions to these properties could be expressed by means of repetitive structural attributes deduced from molecular structures. Carefully formulated configurational and geometrical simplifications enabled to attribute physical meaning to most of the parameters. Overall, the number of adjustable parameters is successfully minimized to less than half compared to the well‐known model proposed by Wesdorp in “Liquid‐multiple solid phase equilibria in fats: theory and experiments” (1990). Comparing both models revealed that the new model surpasses the reference model considering desirable prediction quality, thermodynamical consistency, and the number of adjustable parameters. Practical application: The successful description of the phase behavior of TAG mixtures is crucial to understand complex phenomena in fat‐based products. This objective is based on reliable predictions of pure component properties and non‐ideal mixing in liquid‐ and solid‐phases. The newly formulated model gives reliable descriptions of experimental data and predictions of unknown data of TAGs — both thermodynamically consistent. Those are of benefit as prerequisite for any meaningful effort to predict the solid‐liquid phase behavior of TAG mixtures as well as crystallization kinetics.

Summary Agar extracted from Gracilaria tenuistipitata and commercial agars were incorporated into fish gelatin at various levels (0, 5, 10, 15 and 20% gelatin substitution). G. tenuistipitata agar (GA) had lower failure stress (~16 kPa) than commercial agar (CA) (~20 kPa). However, the former showed higher failure strain (~30%) with lower melting temperature (65.9 °C). The critical linear stress and failure stress of agar/gelatin mixed gels increased with increasing agar levels (P

Summary The personal protective equipment of workers exposed to heat can consist of materials with a relatively low melting point of approximately 250°C (membranes, zippers, and underwear). In particular, users of heat protective clothing (such as volunteer firefighters or industrial workers) are often consider using functional sports underwear for an optimized sweat transport and lower heat stress. However, in an emergency situation (flame engulfment), this kind of clothing can be potentially dangerous because of its low melting temperature. In this study, we investigated the critical heat transfer needed to melt synthetic underwear worn under heat protective clothing and developed a model to predict possible damage to material layers exposed to a flame engulfment condition. The fire protection properties of four clothing systems with varying layer structures were assessed. These combinations were tested on an instrumented manikin according to ISO 13506 (flame engulfment test). The thickness and thermal resistance of the individual garments were measured in order to examine the influence of each parameter on the performance of the complete clothing combination. The measurements showed that synthetic polyester underwear worn underneath heat protective clothing can withstand a 4s flame engulfment exposure without damage when the outer layer has an adequate thermal resistance. By using a simple heat transfer model, we could define a ‘critical thermal resistance’ as the thermal resistance of the outer layer required to prevent the melting of the underwear material. Copyright © 2016 John Wiley & Sons, Ltd.

Characterization of amorphous protein aggregates may offer insights into the process of aggregation. Eleven single amino acid mutants of lipase (LipA of Bacillus subtilis) were subjected to temperature‐induced aggregation, and the resultant aggregates were characterized for recovery of activity in the presence of guanidinium chloride (GdmCl). Based on activity recovery profiles of the aggregates, the mutants could be broadly assigned into four groups. By including at least one mutation from each group, a mutant was generated that showed an increase of ~ 10 °C in melting temperature (T m) compared to the wild‐type and did not aggregate even at 75 °C. This method explores characterization of amorphous protein aggregates in the presence of GdmCl and helps in identifying mutations involved in protein aggregation.

Summary We have investigated the effect of chain length on the thermal denaturation as well as on mechanical unzipping of double stranded DNA (ds-DNA) molecule. We use a simple nonlinear Peyrard Bishop and Dauxois (PBD) model and calculate the melting temperature as well as the critical force as a function of chain length for different heterogeneous chains. We found that in mechanical unzipping, when a force is applied on an end, there is a length up-to which the effect of applied force sustains. The base pairs beyond this length can not feel the force that is applied on the end. We have studied the chain with other end to be open and with the other end to be restricted. By comparing the force required to unzip the chain in these two cases, we found a critical length above which the entropy contribution from the end is not significant to change the duplex state of the chain. For shorter chain, we found that the entropic forces due to open end have significant contribution to change the duplex state of DNA to single strand state of DNA chain.

An efficient procedure was developed to prepare homo-C-nucleosides. The β-allyl C-glycoside of D-ribose was transformed into the thienopyrimidine nucleoside and the benzodiazepine nucleoside of 2-deoxy-D-ribose. For incorporation into oligonucleotides by solid-phase synthesis, both derivatives were transformed into the related 3′-phosphoramidite building blocks. These phosphoramidites were then site-specifically incorporated into DNA oligonucleotides. The modified DNA strands were hybridized with different DNA and RNA strands, and their melting temperatures and circular dichroism spectra were studied. Interestingly, although in the case of DNA–DNA hybrids the nonnatural nucleosides caused a marked decrease in melting temperature, to levels even lower than those for mismatched hybrids, in the case of DNA–RNA hybrids very similar melting temperatures were measured for the nonnatural nucleosides and the unmodified oligonucleotides.

Molecular compound formation between multicomponent triacylglyceride (TAG) mixtures was characterized using palm oil mid fraction enriched in sn-1,3-dipalmitoyl-2-oleoylglycerol (cPOP) and a commercial fraction enriched in sn-1,3-dioleyl-2-palmitoylglycerol containing a wide range of TAGs (cOPO). Compound formation occurred at a 1:1 (w/w) ratio of cPOP to cOPO corresponding to an equal parts ratio of two different families of TAGs. One family of TAGs consisted of a grouping of all TAGs composed of a saturated–oleic–saturated (StUSt) positioning of fatty acids. The second family consisted of a grouping of all TAGs composed of all oleic–saturated–oleic and saturated–saturated–oleic fatty acids (UStU, StStU). An increase in solid fat content, peak melting temperature, and crystalline domain size and a change in crystalline microstructure were observed at this ratio corresponding to an overall equality in the amount of cPOP to cOPO. This indicates that it is possible to achieve that same level of solid fat content and hardness as a mixture containing more saturates, simply by slightly decreasing the saturates and substituting an oleic monounsaturated fatty acid containing TAG mixture such that a molecular compound is formed. The increase in full-width at half-maximum indicated a decrease in crystalline order and/or decrease in crystal domain size. The characteristic spherulitic crystalline microstructure of OPO changed to small granular crystals upon addition of cPOP. This discovery may allow for the incorporation of a larger proportion of healthy monounsaturated fats into foods while decreasing the use of saturated and trans fats.

Upon being released from the N-terminal domain (NTD), the C-terminal domain (CTD) switches from α-helix conformation to β-barrel conformation, which converts RfaH from a transcription factor into an activator of translation. The α→β conformational change may be viewed as allosteric transition. We use molecular dynamics simulations of coarse-grained off-lattice model to study the thermal folding of NTD, CTD, RfaH and the allosteric transition in CTD. The melting temperatures from the specific heat profiles indicate that the β-barrel conformation is much more stable than the α-helix conformation. Two helices in α-helix conformation have similar thermodynamic stabilities and the melting temperatures for β sheets show slight dispersion. Under the interaction with NTD, CTD is greatly stabilized and the cooperativity for thermal folding is also significantly improved. The α→β allosteric transition can be approximately described by a two-state model and three parallel pathways are identified. The transition state ensemble, quantified by a Tanford β-like parameter, resembles the α-helix and β-barrel conformations almost to the same extent. Proteins 2015; 83:1582–1592. © 2015 Wiley Periodicals, Inc.

International audience; Melting experiments of calcite were performed on the join CaCO3-H2O at a pressure of 1000 bars. The system evolves to the ternary CaO-H2O-CO2 system during melting experiments. Our experiments show that partial melting of calcite begins at a low temperature, below 650 °C. Such a low partial melting temperature for carbonates revives the debate about the presence of carbonate melts in the upper crust. More specifically, the conditions for carbonate partial melting are present in carbonate host rocks undergoing contact metamorphism at high temperatures in the presence of water-rich fluid. The presence of carbonate melts influences physical parameters such as viscosity and permeability in contact aureoles, and, furthermore, decarbonation reactions release massive amounts of CO2.

It has been very difficult to detect and quantify multiple somatic mutations simultaneously in single-tube qPCR. Here, a novel method for simultaneous detection of multiple mutations and a melting curve analysis was developed by using clamping PNA and detection PNA probes. Each PNA probe was designed to have a specific melting temperature by the introduction of γ-PNA monomer. This technique was successfully applied to the detection of six genotypes in two different mutations of K-RAS at the same time. Such simultaneous analysis of an amplified curve and a melting curve in qPCR can be widely used for the early diagnosis of cancer and determining the prognosis of drug treatments.

Biaryl derivatives that consist of one DNA-intercalating unit and a sterically demanding component exhibit a specific behavior towards abasic site-containing DNA (AP-DNA) as determined by thermal DNA denaturation experiments, spectrometric titrations and CD spectroscopic analysis. Specifically, these ligands strongly stabilize AP-DNA towards dissociation, whereas they do not or only marginally affect the melting temperature of regular duplex DNA.

The main gelatinization parameters of starches from three maize varieties with wide variation in amylose content (53, 30, and 20%) were obtained using DSC analysis. All starches were characterized by high lipid levels. Gelatinization temperature decreased with increasing amylose content both for native and treated (defatted and annealed) starches. For all studied starches irrespective of amylose content, A-type crystalline packing in semi-crystalline starch granules was observed as judged by the characteristic shift of starch melting temperature in 1 M KCl. Observed shifts of amylopectin melting temperatures to higher values in defatted starches were ascribed to the elution of lipids and/or lipid-containing complexes from crystalline lamellae. Two types of amylose–lipid complexes with different thermostability were detected in aqueous starch gels with concentration equal/more than 10%. It was suggested that the high level of lipids strongly contributed to the gelatinization properties of studied starches.

Summary The effect of osmotic dehydration pretreatment on the quality attributes (e.g. colour, hardness, drip loss, vitamin C content and pH) of frozen mango cuboids in different osmotic solutions (sucrose, glucose and maltose) and concentrations (30, 45 and 60% (wt/wt)) was investigated. Results revealed that melting temperature of mango cuboids was affected by both solute type and solid mass fraction. In addition, the dehydrofrozen samples pretreated in maltose had higher quality in vitamin C content (increasing by 23.5–73.0%), colour (colour change reducing by 2.6–39.2%) and drip loss (reducing by 0.7–9.7%) than those pretreated in other osmotic solutions. The cuboids pretreated in glucose displayed higher hardness (increasing by 16.4–36.2%). Based on principal component analysis and group distance, osmotic dehydration in 45% maltose was proposed as the most favourable freezing conditions with the highest sensory score (6.8). The current work indicates osmotic dehydration significantly improves frozen mango quality.

The thermal history and permafrost evolution in the Urengoy area of the West Siberian basin and in the Kuyumbinskaya area of the Siberian platform during the Pliocene-Quaternary were reconstructed numerically in a forward model from 3.4 Ma using the software package FROST, part of the basin modelling system GALO. Calculations suggest that variations in rock composition with depth strongly influenced permafrost evolution. Rock temperatures decreased by 15–20°C within the upper 1500 m of the sedimentary sequence because of climate cooling in the Pliocene-Holocene. The effect of cooling is greater in the Kuyumbinskaya area, which has a thinner sedimentary cover, than in the more northern Urengoy area. The model estimates permafrost depth and the stability zone of methane gas hydrate. An increase in salt content in porewater from 1 to 30 g/l lowers the melting temperature of ice by 2°С and decreases permafrost thickness by almost 100 m. The change in shape of the unfrozen water curve W(T), dependent upon the lithological composition of sedimentary rocks, strongly influences the numerical estimations of permafrost depth. The modelling demonstrates that permafrost thickness and temperature and heat flow distributions with depth in the basins calculated with climate variations of the last 50 ka differ significantly from the more accurate values obtained with climate variations during the last 200 ka, 1 Ma or 3.4 Ma. Copyright © 2013 John Wiley & Sons, Ltd.

Based on the analysis of the existing evaluation methods and with the combination of the characteristic of cohesive zone characteristic in blast furnace (BF) and softening–melting and dropping experimental result of iron bearing burden, a new evaluation method of softening–melting and dropping characteristic of iron bearing burden was put forward, which can be used for evaluating various kinds of iron bearing burden. The softening–melting and dropping characteristics of the mixed burden and the high metalized burden are evaluated through the new method, which verified that the new method is reasonable and feasible. The results showed that the new method can judge not only the corresponding relation between the shrinking percentage and the unit charge column pressure drop, but also the influence of softening and melting temperature interval, melting temperature interval and dropping temperature interval on the softening–melting and dropping characteristic value of iron bearing burden. This new method is expected to provide technical guidance for BF smelting.

The evolution of the crystalline morphology of two poly(propylene) films deformed in the rubbery state using wide- and small-angle X-ray scattering and extensional rheology experiments is presented. The mechanical behavior can be either isotropic or anisotropic depending on the manufacturing process. The microstructure change of the polymer is linked to the thermomechanical behavior of PP films below and close to the melting temperature. The reorientation of the crystalline phase during the deformation is shown to occur quickly when the deformation temperature is largely lower than the melting temperature and for low strain rates. The formation of a fibrillar structure oriented along the stretching direction following the fragmentation of initial crystals is highlighted.

Electrospraying technique was used for the production of pectin films obtaining transparent and flexible products with thicknesses of 23.4 ± 3.04 µm and requiring a lower pectin solution volume (2.67 × 10−3 mL) than casting (5.97 × 10−3 mL) to produce films of the same area and thickness; the physical, structural, and thermal characteristics of these films were evaluated. Electrosprayed films were slightly more transparent, and with smoother surface than those obtained by casting, but with more and smaller internal pores, resulting in different film densities (0.7 g/cm3 electrospraying, 1.7 g/cm3 casting), that could be linked to the larger water vapor permeability value obtained. These changes could be related to a physical phenomenon, seeing as the percentage of crystallinity and melting temperature remained invariable for both films. These results show that the electrospraying technique has potential in areas such as wound dressings, tissue engineering, and the release of drugs. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43779.

Poly(L-2-hydroxybutyrate) [P(L-2HB)] and poly(D-lactide) (PDLA) in their blends were phase separated to form P(L-2HB)- and PDLA-enriched domains, and heterostereocomplex (HTSC) crystallization occurred at the interface between these domains. In the blends, HTSC crystallites were formed at crystallization temperature (Tc) = 80–160 °C, and their exclusive formation without the formation of other crystalline species was observed at Tc of 150 or 160 °C. The effects of polymer blend ratio on the types of formed crystalline species were very small due to the phase separation of the blends. The presence of a small amount of P(L-2HB) decreased the low limit of crystallizable Tc of PDLA homocrystallites from 80 to 60 °C. The equilibrium melting temperature of HTSC crystallites was 257.6 °C.

The effects of the molecular weight of poly(D-lactic acid) (PDLA), which forms stereocomplex (SC) crystallites with poly(L-lactic acid) (PLLA), and those of processing temperature Tp on the acceleration (or nucleation) of PLLA homocrystallization were investigated using PLLA films containing 10 wt% PDLA with number-average molecular weight (Mn) values of 5.47 × 105, 9.67 × 104 and 3.67 × 104 g mol–1 (PDLA-H, PDLA-M and PDLA-L, respectively). For the PLLA/PDLA-H and PLLA/PDLA-M films, the SC crystallites that were ‘non’-melted and those that were ‘completely’ melted at Tp values just above their endset melting temperature and recrystallized during cooling were found to act as effective accelerating (or nucleation) agents for PLLA homocrystallization. In contrast, SC crystallites formed from PDLA-L, having the lowest Mn, were effective accelerating agents without any restrictions on Tp. In this case, the accelerating effects can be attributed to the plasticizer effect of PDLA-L with the lowest Mn. The accelerating effects of SC crystallites in the PLLA/PDLA-H and PLLA/PDLA-M films was dependent on crystalline thickness for Tp values below the melting peak temperature of SC crystallites, whereas for Tp values above the melting peak temperature the accelerating effects are suggested to be affected by the interaction between the SC crystalline regions and PLLA amorphous regions.

The effects of varying concentrations of incorporated PDLA on the acceleration of PLLA homo-crystallization due to stereocomplex (SC) crystallite formation are investigated in PLLA films doped with PDLA over the wide concentration range of 1–10 wt%. PLLA homo-crystallization is accelerated for all the PDLA concentrations when the processing temperature Tp is just above the endset melting temperature of the SC crystallites (Tp = 226–238 °C), although the appropriate Tp range becomes narrow at low concentrations of PDLA. The accelerating effects of SC crystallites depend on the SC crystalline thickness and the interaction between the SC crystalline regions and PLLA amorphous regions for Tps below and above the melting peak temperature of the SC crystallites, respectively.

Bio-stereo nanocomposite polylactides are prepared by polymerization followed by stereocomplexation in scCO2/dichloromethane through in situ polymerization and master batch processes. The bio-stereo nanocomposite polylactides show intercalated-exfoliated and fully exfoliated nanoscale clay distribution in a perfect stereocomplex polylactide matrix. In situ polymerization proves better strategy to produce well-exfoliated silicate layers in the stereocomplex matrix compared to the MB route that increases the melting temperature by up to � 648C. The thermal properties of these materials maintain both stereocomplex and nanocomposite features simultaneously. The results open a new and versatile way to develop polylactide-based materials.

Although many anticancer drugs exert their biological activity by forming DNA interstrand crosslinks (ICLs), the thermodynamics of biologically relevant long crosslinked DNAs has not been intensively studied in contrast to short duplexes. Here, we carry out computer modeling of the shift of melting temperature of long DNAs caused by ICLs taking into account crosslinking effect in itself and concomitant local alterations in the free energy (δG) of the helix-coil transition at sites of ICLs. Depending on δG, DNA interstrand crosslinks at per nucleotide concentration r = 0.05 can change the melting temperature by value from -17 to +47°C, and the influence weakly depends on DNA sequence and GC content. A change in melting temperature caused by introduction of interstrand crosslinking in modified DNA at sites of modifications also depends on δG and varies from 0 to +12°C. Comparison with experiment for the three platinum crosslinking compounds demonstrates utility of the theoretical method for understanding how crosslinking compounds can influence the melting behavior. On the basis of the method, interdependence of local distortions and crosslinking in itself was studied for thermal effect of ICLs. A method for evaluating the nature of the structural alteration that produces a change in thermal stability for short crosslinked DNA is also proposed. The methods can be used for comparative thermodynamic characterization of various DNA crosslinking agents.

A continuing quest in science is the development of materials capable of operating structurally at ever-increasing temperatures. Indeed, the development of gas-turbine engines for aircraft/aerospace, which has had a seminal impact on our ability to travel, has been controlled by the availability of materials capable of withstanding the higher-temperature hostile environments encountered in these engines. Nickel-base superalloys, particularly as single crystals, represent a crowning achievement here as they can operate in the combustors at ~1100 °C, with hot spots of ~1200 °C. As this represents ~90% of their melting temperature, if higher-temperature engines are ever to be a reality, alternative materials must be utilized. One such class of materials is Mo-Si-B alloys; they have higher density but could operate several hundred degrees hotter. Here we describe the processing and structure versus mechanical properties of Mo-Si-B alloys and further document ways to optimize their nano/microstructures to achieve an appropriate balance of properties to realistically compete with Ni-alloys for elevated-temperature structural applications.

Pathogenic agents can be very hard to detect, and usually they do not cause illness for several hours or days. To improve the speed and the accuracy of detection tests and satisfy the needs of early diagnosis, molecular biology methods such as PCR are now used. However, selecting a proper target gene and designing good primers is often not easy. We present a dedicated website, http://patho-genes.org, where we provide every sequence, functional annotation, published primer and relevant article for every annotated gene of major pathogenic bacterial species listed as key agents to be used for a bioterrorism attack. Each published primer was analysed to determine its melting temperature, its specificity and its coverage (i.e. its sensitivity against every allele of its target gene). Data generated have been organized in the form of data sheet for each gene, which are available through multiple browser panels and query systems.