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Nano- and micro-sized vesicular and colloidal structures mediate cell–cell communication. They are important players in the physiology of plants, animals, and humans, and are a subject of increasing interest. We investigated the effect of three surfactants, N-cetylpyridinium chloride (CPC), sodium dodecyl sulfate (SDS), and Triton X-100 (TX100), and two anionic polyelectrolytes, sodium polystyrene sulfonate (NaPSS) and sodium polymethacrylate (NaPMA), on nanoliposomes. In addition, the effect of SDS and TX100 on selected biological membranes (erythrocytes and microalgae) was investigated. The liposomes were produced by extrusion and evaluated by microcalorimetry and light scattering, based on the total intensity of the scattered light (Itot), hydrodynamic radius (Rh), radius of gyration (Rg), shape parameter p (=Rh/Rg,0), and polydispersity index. The EPs shed from erythrocytes and microalgae Dunaliella tertiolecta and Phaeodactylum tricornutum were visualized by scanning electron microscopy (SEM) and analyzed by flow cytometry (FCM). The Rh and Itot values in POPC liposome suspensions with added CPC, SDS, and TX100 were roughly constant up to the respective critical micelle concentrations (CMCs) of the surfactants. At higher compound concentrations, Itot dropped towards zero, whereas Rh increased to values higher than in pure POPC suspensions (Rh ≈ 60–70 nm), indicating the disintegration of liposomes and formation of larger particles, i.e., various POPC–S aggregates. Nanoliposomes were stable upon the addition of NaPSS and NaPMA, as indicated by the constant Rh and Itot values. The interaction of CPC, SDS, or TX100 with liposomes was exothermic, while there were no measurable heat effects with NaPSS or NaPMA. The SDS and TX100 increased the number density of EPs several-fold in erythrocyte suspensions and up to 30-fold in the conditioned media of Dunaliella tertiolecta at the expense of the number density of cells, which decreased to less than 5% in erythrocytes and several-fold in Dunaliella tertiolecta. The SDS and TX100 did not affect the number density of the microalgae Phaeodactylum tricornutum, while the number density of EPs was lower in the conditioned media than in the control, but increased several-fold in a concentration-dependent manner. Our results indicate that amphiphilic molecules need to be organized in nanosized particles to match the local curvature of the membrane for facilitated uptake. To pursue this hypothesis, other surfactants and biological membranes should be studied in the future for more general conclusions. [ABSTRACT FROM AUTHOR]

Spread of multidrug-resistant Pseudomonas aeruginosa strains threatens to render currently available antibiotics obsolete, with limited prospects for the development of new antibiotics. Lytic bacteriophages, the viruses of bacteria, represent a path to combat this threat. In vitro-directed evolution is traditionally applied to expand the bacteriophage host range or increase bacterial suppression in planktonic cultures. However, while up to 80% of human microbial infections are biofilm-associated, research towards targeted improvement of bacteriophages' ability to combat biofilms remains scarce. This study aims at an in vitro biofilm evolution assay to improve multiple bacteriophage parameters in parallel and the optimisation of bacteriophage cocktail design by exploiting a bacterial bacteriophage resistance trade-off. The evolved bacteriophages show an expanded host spectrum, improved antimicrobial efficacy and enhanced antibiofilm performance, as assessed by isothermal microcalorimetry and quantitative polymerase chain reaction, respectively. Our two-phage cocktail reveals further improved antimicrobial efficacy without incurring dual-bacteriophage-resistance in treated bacteria. We anticipate this assay will allow a better understanding of phenotypic-genomic relationships in bacteriophages and enable the training of bacteriophages against other desired pathogens. This, in turn, will strengthen bacteriophage therapy as a treatment adjunct to improve clinical outcomes of multidrug-resistant bacterial infections. Using a biofilm evolution assay, this study improves the antimicrobial and antibiofilm efficacy of Pseudomonas aeruginosa bacteriophages, while a two-phage cocktail shows further improved antimicrobial efficacy without incurring dual-bacteriophage-resistance. [ABSTRACT FROM AUTHOR]

Despite the appealing properties of random copolymers, the use of these biomaterials in association with phospholipids is still limited, as several aspects of their performance have not been investigated. The aim of this work is the formulation of lipid/random copolymer platforms and the comprehensive study of their features by multiple advanced characterization techniques. Both biomaterials are amphiphilic, including two phospholipids (1,2-dioctadecanoyl-sn-glycero-3-phosphocholine (DSPC), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)) and a statistical copolymer of oligo (ethylene glycol) methyl ether methacrylate (OEGMA) and 2-(diisopropylamino) ethyl methacrylate (DIPAEMA). We examined the design parameters, including the lipid composition, the % comonomer ratio, and the lipid-to-polymer ratio that could be critical for their behavior. The structures were also probed in different conditions. To the best of the authors' knowledge, this is the first time that P(OEGMA-co-DIPAEMA)/lipid hybrid colloidal dispersions have been investigated from a membrane mechanics, biophysical, and morphological perspective. Among other parameters, the copolymer architecture and the hydrophilic to hydrophobic balance are deemed fundamental parameters for the biomaterial co-assembly, having an impact on the membrane's fluidity, morphology, and thermodynamics. Exploiting their unique characteristics, the most promising candidates were utilized for methotrexate (MTX) loading to explore their encapsulation capability and potential antitumor efficacy in vitro in various cell lines. [ABSTRACT FROM AUTHOR]

• Metal(loid)s content and mobility were correlated to microbial activities. • Microbial activities are sensitive bioindicators for metal-contaminated sites. • Surface and 1 m deep layers reached alarming and serious pollution levels. • Cadmium and possibly arsenic were the main contributors to the environmental risk. • Modified combined pollution risk was based on chemical and toxicological indices. Abandoned chemical smelting sites containing toxic substances can seriously threaten and pose a risk to the surrounding ecological environment. Soil samples were collected from different depths (0 to 13 m) and analyzed for metal(loid)s content and fractionation, as well as microbial activities. The potential ecological risk indices for the different soil depths (ordered from high to low) were: 1 m (D-1) > surface (S-0) > 5 m (D-5) > 13 m (D-13) > 9 m (D-9), ranging between 1840.65–13,089.62, and representing extremely high environmental risks, of which Cd (and probably not arsenic) contributed to the highest environmental risk. A modified combined pollution risk index (MCR) combining total content and mobile proportion of metal(loid)s, and relative toxicities, was used to evaluate the degree of contamination and potential environmental risks. For the near-surface samples (S-0 and D-1 layers), the MCR considered that As, Cd, Pb, Sb, and Zn achieved high and alarming degrees of contamination, whereas Fe, Mn, and Ti were negligible or low to moderate pollution degrees. Combined microcalorimetry and enzymatic activity measurements of contaminated soil samples were used to assess the microbial metabolic activity characteristics. Correlation analysis elucidated the relationship between metal(loid)s exchangeable fraction or content and microbial activity characteristics (p < 0.05). The microbial metabolic activity in the D-1 layer was low presumably due to heavy metal stress. Enzyme activity indicators and microcalorimetric growth rate (k) measurements were considered sensitive indicators to reflect the soil microbial activities in abandoned chemical smelting sites. [Display omitted] [ABSTRACT FROM AUTHOR]

Introduction/purpose: Gunpowder is a type of explosive material (EM), a mixture of chemical compounds capable of releasing their potential energy in a very fast exothermic chemical reaction. This paper investigates the single base gunpowder samples. Methods: Microcalorimetry (MC), or heat flow calorimetry (HFC), is the only modern method that monitors the direct cause of autoignition - the rate of heat release, which is a key factor for gunpowder storage explosive safety. It is based on high-sensitivity calorimeters which allow monitoring of chemical reactions at low speeds. The microcalorimeter "TAM III" was used and the method given by the NATO standard STANAG 4582. A very reliable result was obtained on the chemical stability of the observed single base gunpowder samples, as well as an assessment of its behavior in the next 10 years. Results: The thermal activity of gunpowder depends on several factors, the most important of which are: chemical composition, size and shape of the gunpowder grain, the degree of decomposition of the gunpowder, storage conditions, etc. Namely, it is a much more exact and consistent indicator of the chemical stability of gunpowder compared to the critical diameter. Conclusion: The MC method should be used both for monitoring the chemical stability of gunpowder during storage and for the prediction of the service life of gunpowder.

Introduction/purpose: Gunpowder is a type of explosive material (EM), a mixture of chemical compounds capable of releasing their potential energy in a very fast exothermic chemical reaction. This paper investigates the single base gunpowder samples. Methods: Microcalorimetry (MC), or heat flow calorimetry (HFC), is the only modern method that monitors the direct cause of autoignition - the rate of heat release, which is a key factor for gunpowder storage explosive safety. It is based on high-sensitivity calorimeters which allow monitoring of chemical reactions at low speeds. The microcalorimeter "TAM III" was used and the method given by the NATO standard STANAG 4582. A very reliable result was obtained on the chemical stability of the observed single base gunpowder samples, as well as an assessment of its behavior in the next 10 years. Results: The thermal activity of gunpowder depends on several factors, the most important of which are: chemical composition, size and shape of the gunpowder grain, the degree of decomposition of the gunpowder, storage conditions, etc. Namely, it is a much more exact and consistent indicator of the chemical stability of gunpowder compared to the critical diameter. Conclusion: The MC method should be used both for monitoring the chemical stability of gunpowder during storage and for the prediction of the service life of gunpowder. [ABSTRACT FROM AUTHOR]

Isothermal microcalorimetry (IMC) is a potent analytical method for the realtime assessment of microbial metabolic activity, which serves as an indicator of microbial viability. This approach is highly relevant to the fields of probiotics and Live Biotherapeutic Products (LBPs), offering insights into microbial viability and growth kinetics. One important characteristic of IMC is its ability to measure microbial metabolic activity separately from cellular enumeration. This is particularly useful in situations where continuous tracking of bacterial activity is challenging. The focus on metabolic activity significantly benefits both probiotic research and industrial microbiology applications. IMC's versatility in handling different media matrices allows for the implementation of viability assessments under conditions that mirror those found in various industrial environments or biological models. In our study, we provide a proof of concept for the application of IMC in determining viability and growth dynamics and their correlation with bacterial count in probiotic organisms. Our findings reinforce the potential of IMC as a key method for process enhancement and accurate strain characterization within the probiotic sector. This supports the broader objective of refining the systematic approach and methods used during the development process, thereby providing detailed insights into probiotics and LBPs. [ABSTRACT FROM AUTHOR]

Solid–liquid interfacial phenomena play an essential role in our everyday lives and are often regarded as the outcome of interactions at the solid–liquid interface. However, the intricately intrinsic mechanism underlying interfacial interactions renders in situ simulations and direct measurements challenging. As an effective analytic method for studying solid–liquid interfacial interactions, microcalorimetry can provide the most basic thermodynamic information (including changes in enthalpy, entropy, and Gibbs free energy during solid–liquid binding/separation processes), which is extremely crucial for understanding interaction directionality and limitation. This review is dedicated to highlighting the pivotal role of microcalorimetry in studying solid–liquid immersion and adsorption processes. Specifically, we provide an overview of the commonly employed microcalorimetric methods, including differential scanning calorimetry (DSC), isothermal titration calorimetry (ITC), and immersion microcalorimetry (IM), and delve into the influence factors of enthalpy change, and finally discuss the specific applications of microcalorimetry in studying various solid–liquid binding processes. There remains a vast expanse of thermodynamic information regarding solid–liquid interactions that await exploration via calorimetry. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Dalian Polytechnic University is the property of Journal of Dalian Polytechnic University Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: The aim of this in-vitro study was to investigate the antimicrobial efficacy of identical experimental toothpastes with different stannous sources. Materials and Methods: Streptococcus mutans biofilms were grown on protein-coated glass disks in static conditions for 24 h and thereafter exposed to toothpaste slurries or physiological saline (negative control; n = 15) for 30 s. Four experimental toothpastes were applied in this study, containing either stannous chloride (SnCl2; B: 3500 ppm Sn2+, and D: 3600 ppm Sn2+) or stannous fluoride (SnF2; C: 3500 ppm Sn2+, and E: 3600 ppm Sn2+). Marketed toothpaste meridol® (A: 3300 ppm SnF2) served as control. All five toothpastes contained amine fluoride (AmF). The biofilms were placed on agar surface and their metabolic activity was assessed by isothermal microcalorimetry over 96 h. The heat flow data was analysed for growth rate and lag time using grofit package in software R. Additionally, reduction of active biofilm compared to untreated control was calculated. Results: All toothpastes significantly prolong the lag time of treated biofilms in comparison to negative control (p < 0.05). Toothpastes containing SnF2 (C and E) prolonged the lag time statistically significantly compared to toothpastes containing SnCl2 (B and D) (p < 0.05). The maximum growth rate was statistically significantly reduced by all tested toothpastes compared to the untreated control group (p < 0.05). Toothpastes containing SnF2 (A, C and E) reached 59.9 ± 7.8, 61.9 ± 7.7, and 55.6 ± 7.0% reduction of active biofilm, respectively. Thus, they exhibit statistically significantly better results than toothpastes B (52.9 ± 9.9%) and D (44.7 ± 7.6%). Toothpaste D, which contains a slightly higher concentration of Sn2+, was the least effective in reducing active biofilm. Conclusion: The toothpastes containing SnF2 combined with AmF had the highest antimicrobial efficacy in this study. [ABSTRACT FROM AUTHOR]

Solid–liquid interfacial phenomena play an essential role in our everyday lives and are often regarded as the outcome of interactions at the solid–liquid interface. However, the intricately intrinsic mechanism underlying interfacial interactions renders in situ simulations and direct measurements challenging. As an effective analytic method for studying solid–liquid interfacial interactions, microcalorimetry can provide the most basic thermodynamic information (including changes in enthalpy, entropy, and Gibbs free energy during solid–liquid binding/separation processes), which is extremely crucial for understanding interaction directionality and limitation. This review is dedicated to highlighting the pivotal role of microcalorimetry in studying solid–liquid immersion and adsorption processes. Specifically, we provide an overview of the commonly employed microcalorimetric methods, including differential scanning calorimetry (DSC), isothermal titration calorimetry (ITC), and immersion microcalorimetry (IM), and delve into the influence factors of enthalpy change, and finally discuss the specific applications of microcalorimetry in studying various solid–liquid binding processes. There remains a vast expanse of thermodynamic information regarding solid–liquid interactions that await exploration via calorimetry.

Copyright of Advances in Biochemistry / Postepy Biochemii is the property of Polish Biochemical Society / Acta Biochimica Polonica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A new experimental method for the estimation of kinetic parameters using the signal of the heat flow from a differential scanning calorimeter is presented. An isothermal gas solid reaction was carried out in a differential scanning calorimeter (DSC) in continuous flow on a fixed bed of catalyst in the crucible. An instantaneous energy balance in steady state was made for estimate the total heat flow produced by the reaction and deduce the kinetics parameters. Hydrogenation of CO2 on Ni/Al2O3 solid catalyst was used to produce methane as base reaction. This reaction was chosen because it is very exothermic, and also a well-known reaction in terms of kinetics. A large range of stochiometric and non-stochiometric operating conditions were studied with ratios of reactants H2/CO2 between 3 and 7, diluted with N2 at different isothermal conditions in an interval of temperature between 573 and 673 K for different flow rates of mixture of gases. CO2 methanation involves several reactions in parallel where the main ones are the Sabatier reaction and the reverse water gas shift (RWGS) reaction. To keep the isothermicity of the catalytic bed, a theorical analysis of heat and mass transfer limitations was carried out to determine the absence of the internal and external limitation in the kinetic data. [ABSTRACT FROM AUTHOR]

In order to improve the detonation characteristics of RDX, a RDX-based composite explosive with TiH2 powders was prepared. The effects of content and particle size of TiH2 powders on thermal safety, shock wave parameters and thermal damage effects of RDX-based composite explosive were studied with the C80 microcalorimeter, air blast experiment system and colorimetric thermometry method. Experimental results showed that TiH2 powders could enhance the thermal stability of RDX-based composite explosive and increase its ultimate decomposition heat. The content and particle size of TiH2 powders also had significant effects on the thermal safety, detonation velocity, shock wave parameters, fireball temperature and duration of RDX-based composite explosives. Furthermore, the differences of TiH2 and Ti powders on the detonation energy output rules of RDX-based composite explosives were also compared, showing that TiH2 powders had better influences on improving the explosion power and thermal damage effect of RDX-based composite explosives than Ti powders, for the participation of free H2 released by TiH2 powders in the detonation process. TiH2 powders have important research values as a novel energetic additive in the field of military composite explosives [ABSTRACT FROM AUTHOR]

Two compatibility test types based on gas generation obtained by vacuum stability test (VST) procedure and on heat generation obtained by heat flow microcalorimetry (HFMC) show that nitroguanidine (NGu), CAS‐No. [556‐88‐7], is compatible with ammonium nitrate (AN), CAS‐No. [6484‐52‐2], ammonium dinitramide (ADN), CAS‐No. [140456‐78‐6], 1,1‐diamino‐dinitroethylene (FOX‐7, DADNE), CAS‐No. [145250‐81‐3], N‐guanylurea dinitramide (FOX‐12, GUDN, carbamoylguanidinium dinitramide), CAS‐No. [217464‐38‐5], hexogen (RDX), CAS‐No. [121‐82‐4], octogen (HMX), CAS‐No. [2691‐41‐0], and trinitrotoluene (TNT), CAS‐No. [118‐96‐7]. The evaluations with gas generation and heat generation were done using the so‐called corresponding reactivity quantities RV and RQ, but the assessment criteria are in accordance with the present NATO standards. NGu and ADN show the rare case of reactivity with a negative assessment quantity, that is their inter‐component reactivity quantities show negative values in RV and RQ. The evolved gas volume and the produced heat generation of the 1 : 1 mixture have lower values than the formally calculated values of the mixture. The root cause of this cannot be deduced with mere compatibility testing. A negative assessment quantity RQ is also observed with NGu and TNT at 80 °C, but not at 70 °C. [ABSTRACT FROM AUTHOR]

Nano- and micro-sized vesicular and colloidal structures mediate cell–cell communication. They are important players in the physiology of plants, animals, and humans, and are a subject of increasing interest. We investigated the effect of three surfactants, N-cetylpyridinium chloride (CPC), sodium dodecyl sulfate (SDS), and Triton X-100 (TX100), and two anionic polyelectrolytes, sodium polystyrene sulfonate (NaPSS) and sodium polymethacrylate (NaPMA), on nanoliposomes. In addition, the effect of SDS and TX100 on selected biological membranes (erythrocytes and microalgae) was investigated. The liposomes were produced by extrusion and evaluated by microcalorimetry and light scattering, based on the total intensity of the scattered light (Itot), hydrodynamic radius (Rh), radius of gyration (Rg), shape parameter p (=Rh/Rg,0), and polydispersity index. The EPs shed from erythrocytes and microalgae Dunaliella tertiolecta and Phaeodactylum tricornutum were visualized by scanning electron microscopy (SEM) and analyzed by flow cytometry (FCM). The Rh and Itot values in POPC liposome suspensions with added CPC, SDS, and TX100 were roughly constant up to the respective critical micelle concentrations (CMCs) of the surfactants. At higher compound concentrations, Itot dropped towards zero, whereas Rh increased to values higher than in pure POPC suspensions (Rh ≈ 60–70 nm), indicating the disintegration of liposomes and formation of larger particles, i.e., various POPC–S aggregates. Nanoliposomes were stable upon the addition of NaPSS and NaPMA, as indicated by the constant Rh and Itot values. The interaction of CPC, SDS, or TX100 with liposomes was exothermic, while there were no measurable heat effects with NaPSS or NaPMA. The SDS and TX100 increased the number density of EPs several-fold in erythrocyte suspensions and up to 30-fold in the conditioned media of Dunaliella tertiolecta at the expense of the number density of cells, which decreased to less than 5% in erythrocytes and several-fold in Dunaliella tertiolecta. The SDS and TX100 did not affect the number density of the microalgae Phaeodactylum tricornutum, while the number density of EPs was lower in the conditioned media than in the control, but increased several-fold in a concentration-dependent manner. Our results indicate that amphiphilic molecules need to be organized in nanosized particles to match the local curvature of the membrane for facilitated uptake. To pursue this hypothesis, other surfactants and biological membranes should be studied in the future for more general conclusions.

Investigations on electrochemical kinetics usually rely on the measurement of current or potential as a function of time. Charge‐neutral process steps or side reactions are naturally disguised in the electrical signals and have only indirect impact. However, all processes will contribute to heat evolution. In this work, heat absorption/liberation is measured as a function of time for pulsed Na deposition/dissolution on a Na‐electrode in a 1 m NaPF6/diglyme solution, in addition to the standard electrochemical signals. While potential and current transients both exhibited sharp rectangular shapes, indicating instantaneous electrochemical Na deposition or dissolution on the time scale of the pulse (10 ms), heat absorption or liberation continued up to about 0.5 s after the pulse. Since heat evolution is to large extent reversible, this corresponded to entropy changes in the absence of external electric current flow, pointing to a reversible, charge‐neutral chemical process accompanying Na deposition or dissolution. From the observed entropy changes, it is suggested that upon Na deposition solvated Na+ ions are instantaneously transferred into the outer layers of the solid electrolyte interphase, followed by slow desolvation. [ABSTRACT FROM AUTHOR]

Background. Charcoal increases in reflectance with increased intensity and/or duration of heating, and this has been proposed as a potential quantitative metric for fire severity. Because fuel properties also influence reflectance, relationships between heat exposure and reflectance must currently be considered fuel-specific, limiting the application of the method. Aims. We assessed the effect of wood density on charcoal reflectance, to test whether it could be used as a proxy for overall variation in wood properties. Methods. Wood samples from 25 tree species were charred under constant conditions in a microcalorimeter, and reflectance measured by microphotometry. Key results. A positive linear relationship was found between wood density and charcoal reflectance (r = 0.53). Wood density was highly correlated with total heat release per unit volume (r = 0.94). Conclusions. Wood density accounts for a substantial component of the variation in charcoal reflectance under constant heat exposure. Implications. The relationship of density to reflectance shown here is relevant to the assessment of charcoals formed anaerobically, where endogenous heating (combustion of the sample itself) does not occur. In fire-produced chars, an additional increase in reflectance from endogenous heating should produce a stronger correlation, and density might account for a large component of the variation in reflectance under such conditions. [ABSTRACT FROM AUTHOR]

Increasing lithium‐ion batteries' (LIBs) electrode areal capacity can boost energy density and lower manufacturing costs, but faces challenges in manufacturing, rate performance, and cycling stability. A conductive framework made of commercial micro‐sized carbon fibers (Cfs) is presented that serves as a host for both the LiNi0.5Mn0.3Co0.2O2 (NMC 532) cathode and Cfs anode. The Cf framework has multiple functions that offer high electronic conductivity (270 mS cm−1), low tortuosity (1.7), low Li+ diffusion resistance (22 Ω), and high thermal conductivity (200 W mK−1). Additionally, the Cf‐integrated electrodes can have an extremely high mass loading of NMC 532 (70 mg cm−2) with a theoretical capacity of 14 mAh cm−2. Thus, the practical full cells assembled with the Cfs‐enabled electrodes exhibit an initial areal capacity of 4.1 mAh cm−2 and capacity retention of 90.4% at 500 cycles at a cycling rate of C/3, 1.5 mA cm−2. Data collected from the operando isothermal microcalorimetry suggest that full cells utilizing the Cf anode experience less heat release from side reactions compared to cells utilizing a conventional graphite anode. This present approach is scalable and cost‐effective and can fabricate practical LIBs that boast high areal capacity, rate performance, and a lengthy cycling lifetime. [ABSTRACT FROM AUTHOR]

The thermodynamic parameters of the complexes of Th with N-methylethylenediamine-N,N',N'-triacetic acid (MEDTA; denoted as H3L with three dissociable protons) were studied. Potentiometry and microcalorimetry were used to determine formation constants and enthalpies, respectively. Thermodynamic analysis revealed two successively formed complexes, namely, ThL+ and ThL22-(L3-denotes the totally deprotonated MEDTA). Results indicated that both complexation reactions were exothermic and driven by entropic force. The first stepwise reaction (Th4+ + L3- = ThL+) was mainly driven by entropy with minimal effect on enthalpy change. The second stepwise reaction (ThL+ + L3- = ThL22-) was more exothermic and showed less entropic change than the first stepwise reaction. The strong chelation of MEDTA would inhibit the hydrolysis of Th4+ and increase solubility. [ABSTRACT FROM AUTHOR]

Ganoderma P. Karst has species of pharmacological and commercial importance, whose bioactives are used against diseases such as cancer. In Sonora, Mexico, vineyard pruning is one of the most abundant agricultural residues whose chemical composition favors the growth and development of this fungus. The objective of this study was to evaluate the metabolism of Ganoderma species grown in liquid medium with and without elicitors derived from vineyard pruning extracts of different polarities using isothermal microcalorimetry. A commercial strain of G. lucidum (control strain) and five native strains of G. curtisii, G. oerstedii, G. sessiliforme, G. subincrustatum and G. weberianum were evaluated using an isothermal microcalorimeter to determine the growth rate (µMax), lag phase (λ), net heat generated (MaxQ) and peak heat production time (T). For each of the strains, control and two treatments with vineyard pruning extracts were used. The native strains had a higher metabolic yield versus the control strain. The treatments increased the growth rate of the strains, except for G. oerstedii and G. lucidum, while G. curtisii and G. weberianum exhibited the best behavior compared to the control. Ganoderma curtisii strain showed a shorter lag phase and a considerable increase in growth rate with vineyard pruning extracts. The technique showed potential to help determine the concentration and effect time of the elicitor that produces the liquid culture of Ganoderma species that have more metabolic activity. [ABSTRACT FROM AUTHOR]

Mechanistic studies of Geobacillus stearothermophilus tryptophanyl-tRNA synthetase (TrpRS) afford an unusually detailed description—the escapement mechanism—for the distinct steps coupling catalysis to domain motion, efficiently converting the free energy of ATP hydrolysis into biologically useful alternative forms of information and work. Further elucidation of the escapement mechanism requires understanding thermodynamic linkages between domain configuration and conformational stability. To that end, we compare experimental thermal melting of fully liganded and apo TrpRS with a computational simulation of the melting of its fully liganded form. The simulation also provides important structural cameos at successively higher temperatures, enabling more confident interpretation. Experimental and simulated melting both proceed through a succession of three transitions at successively higher temperature. The low-temperature transition occurs at approximately the growth temperature of the organism and so may be functionally relevant but remains too subtle to characterize structurally. Structural metrics from the simulation imply that the two higher-temperature transitions entail forming a molten globular state followed by unfolding of secondary structures. Ligands that stabilize the enzyme in a pre-transition (PreTS) state compress the temperature range over which these transitions occur and sharpen the transitions to the molten globule and fully denatured states, while broadening the low-temperature transition. The experimental enthalpy changes provide a key parameter necessary to convert changes in melting temperature of combinatorial mutants into mutationally induced conformational free energy changes. The TrpRS urzyme, an excerpted model representing an early ancestral form, containing virtually the entire catalytic apparatus, remains largely intact at the highest simulated temperatures. [ABSTRACT FROM AUTHOR]

The thermochemical and kinetic studies of the formation of iodine (I2) and 4-(dimethylamino) pyridine (DMAP) complexes in solution were investigated using microcalorimetry at 25 °C. First, a theoretical approach of the σ-hole bonding leading to these complexes based on the calculation of complexation energy values, Vsmin,max, localization of the molecular orbitals and the amount of charge transfer, was developed. The hexane was chosen as a solvent for both DMAP and I2 solids. The plots of the complexation heats as a function of r1 = [DMAP]/[I2] and r2 = [I2]/[DMAP] ratios (where [DMAP] and [I2] are the concentrations of DMAP and I2, respectively) show that mixing DMAP solution to I2 ones or vice versa has the same tendency but do not lead to the same enthalpies and is not a reciprocal phenomenon. For particular r1 and r2 values, we can suggest complex forms for the reaction between I2 and DMAP by taking into account the measured and calculated complexation energies. The kinetic mechanisms and theoretical heat flow equations have been proposed for the lowest and highest r1 and r2 ratios. Iterating the heat flow equations while considering the deconvoluted curves allows to deduce the kinetic and thermodynamic parameters as: global order, partial order, rate constant, apparent rate constant and complexation enthalpies: for each mechanism, the latter parameter agrees with both the measured and theoretical ones. [ABSTRACT FROM AUTHOR]

In an effort to measure electron-impact ionization (EII) cross-sections of He-like F e 24 + at the electron beam ion trap (EBIT) facility of the National Institute of Standards and Technology (NIST), we have experimentally determined the corrections to the nominal beam energy determined by the voltages applied to the EBIT. High-resolution X-ray spectra were recorded at nominal electron beam energies between 6660 eV and 6750 eV using X-ray microcalorimetry based upon an array of 192 transition-edge sensors (TES). A large-scale collisional-radiative simulation of the non-Maxwellian EBIT plasma using relevant atomic data calculated with Flexible Atomic Code allowed us to determine the space-charge correction due to the electron beam including the neutralization factor by the ion cloud of the EBIT. [ABSTRACT FROM AUTHOR]

This study aimed to use microcalorimetry to analyze the real-time effect that silver nitrate has on one of the most common bacteria involved in severe infections in current medical practice. Using a Calvet microcalorimeter, the heat output produced by Pseudomonas aeruginosa was determined when exposed to concentrations of silver nitrate from 0 to 3 mol⋅m−3, and a saturated solution. Under physiological human body temperature, for 46 h, thermographic curves were obtained. The maximum voltage peaks (Vmax) and the total amount of heat exchanged (Q) were determined. The results showed a bactericidal effect, with a minimum inhibitory concentration (MIC) of silver nitrate of 0.75 mol⋅m−3, showing a Vmax of 93 μV and Q of 193 kJ. With higher concentrations of this metallic solution, the results highlighted the proportional negative effect that silver nitrate has in Pseudomonas aeruginosa growth. [ABSTRACT FROM AUTHOR]

This work assessed the properties of the hydration processes and the strength development of synthesised belite cement samples. The belite clinker was synthesized in the high-temperature furnace by calcining the mixture of industrial waste (~ 18%) (granite cutting waste and silica-gel waste from AlF3 production) and natural raw materials (~ 82%) at 1150 °C temperature for 2 h. It was obtained that the produced binder was composed mainly of larnite, mayenite, srebrodolskite, ye'elimite, and gehlenite. Furthermore, the synthesized clinker was blended with gypsum (5–20%) to determine the required amount of gypsum additive for the hydration process. The results of microcalorimetry analysis showed that the amount of gypsum plays an important role in the hydration process because, in the samples with 5% or 7.5% of additive, two exothermic reactions were identified, while in the samples with a higher amount of additive 3–4 exothermic reactions were identified. The mechanical properties of prepared concrete were determined by curing the standard prisms (according to the standard of EN 196–1, cement/sand = 1:3, w/c = 0.67) in an aqueous (25 °C, for 3–90 days) or hydrothermal (90 °C, 125 °C, or 175 °C, for 24 h) environment. The results of a compressive test demonstrated that the curing method significantly affects the compressive strength development of produced belite concrete, and the highest value (> 18 MPa) was obtained after hydrothermal curing at 175 °C. The mineralogical composition of formed hydrates was determined by X-ray diffraction analysis and simultaneous thermal analysis. [ABSTRACT FROM AUTHOR]

Traceability for power measurements at high millimeter-wave and terahertz frequencies presents significant challenges since traditional waveguide micro-calorimetry systems are only readily available at frequencies up to 110 GHz. There are, however, different types of commercially available power meters which operate at frequencies above 110 GHz, where a lack of traceability means the accuracy and associated uncertainty of measurements using these power meters is not well understood. This paper describes the characterisation and traceable calibration of a commercially available waveguide power meter (VDI Erickson PM5) which is designed to operate from 75 GHz to 3 THz, using appropriate waveguide tapers. This includes an assessment of the overall system performance along with an evaluation of the uncertainty in measurements made using the system. The assessment is carried out at W-band (75 to 110 GHz) by comparison with micro-calorimeter systems which are used as primary standard power measurement systems at these frequencies. [ABSTRACT FROM AUTHOR]

Accelerated thermal ageing (ATA) coupled to mechanical testing is widely used to predict the lifetime of polymeric products. ATA implies that the mechanisms of ageing are the same at accelerated and service conditions, which may often not be the case. Hence, ageing closer to service conditions is of high importance, but require very sensitive tools. Therefore, a high sensitivity microcalorimetry (MC) method was applied here to assess if it can be a possible tool for lifetime/ageing prediction closer to service conditions. We chose to focus on a complex, yet commonly used, ethylene-propylene-diene terpolymer (EPDM) rubber. Arrhenius extrapolation of the heat flow data indicated two regimes at low and high temperature, with the former having the lower activation energy. The heat flow values measured by the MC revealed contributions from processes such as the melting of the antioxidant, its consumption at low temperature and the breakdown of residual peroxide. MC tests on the EPDM indicated a very low degree of oxidation appearing above 100 °C, too low to be observed with infra-red spectroscopy (FTIR), but noticeable with MC. The high sensitivity of the MC techniques enabled detection of early signs of polymer degradation/ageing and other thermally activated processes that take place at or close to service temperatures (such as those in nuclear power plants). The MC tests were combined with other techniques, such as scanning electron microscopy/energy dispersive X-ray spectroscopy, gas chromatography techniques, differential scanning calorimetry and FTIR to further understand the degradation mechanisms.

Flavonoids are exogenous phytochemicals with high antioxidative potential. The present work provides the mechanism of the complexations of low water-soluble flavanone naringenin, its glycosylated form naringin, and water-soluble flavan-3-ol catechin with β-cyclodextrin (βCD) and hydroxypropyl-β-cyclodextrin (HPβCD). The flavonoids studied showed high affinity in the interactions with HPβCD (the association constants K and the stoichiometry N were equal to 8500 ± 950 М−1 and 0.85 ± 0.05, 9400 ± 1200 М−1 and 1.7 ± 0.10, 7550 ± 600 M−1 and 1.25 ± 0.05 in the case of naringenin, naringin and catechin, respectively). The formations of the complexes with β-cyclodextrins markedly increased the water solubility of naringenin and naringin. The flavonoid–HPβСD complexations were exothermic (ΔH ˂ 0) and spontaneous (ΔG ˂ 0). The naringenin and naringin complexations with HPβCD were entropy-driven, and the catechin complexation was enthalpy-driven. Flavonoid molecules dispersed in the HPβCD structure during complexations. The flavonoid–HPβCD associations demonstrated enthalpy–entropy compensation. Naringenin (5–50 μM) and, to a lesser extent, catechin inhibited the respiration of isolated rat liver mitochondria. Naringenin, naringin and catechin (5–25 μM) increased the rate of Ca2+-induced mitochondrial permeability transition. The complexations with HPβCD did not significantly influence the effects of the flavonoids on respiration and enhanced the effects on mitochondrial permeability transition. The naringenin and naringin complexations with 2-hydroxypropyl-β-cyclodextrin (HPβCD) are entropy-driven The catechin complexation with HPβCD is enthalpy-driven Flavonoid–HPβCD associations demonstrated enthalpy–entropy compensation The naringenin/naringenin–HPβCD complex inhibits mitochondrial respiration due to uncoupling The flavonoids/flavonoid–HPβCD complexes enhance mitochondrial pore formation [ABSTRACT FROM AUTHOR]

Infections involving antibiotic resistant Staphylococcus aureus (S. aureus) represent a major challenge to successful treatment. Further, although bacteriophages (phages) could be an alternative to antibiotics, there exists a lack of correlation in phage susceptibility results between conventional in vitro and in vivo assays. This discrepancy may hinder the potential implementation of bacteriophage therapy. In this study, the susceptibility of twelve S. aureus strains to three commercial phage cocktails and two single phages was assessed. These S. aureus strains (including ten clinical isolates, five of which were methicillin-resistant) were compared using four assays: the spot test, efficiency of plating (EOP), the optical density assay (all in culture media) and microcalorimetry in human serum. In the spot test, EOP and optical density assay, all cocktails and single phages lysed both methicillin susceptible and methicillin resistant S. aureus strains. However, there was an absence of phage-mediated lysis in high concentrations of human serum as measured using microcalorimetry. As this microcalorimetry-based assay more closely resembles in vivo conditions, we propose that microcalorimetry could be included as a useful addition to conventional assays, thereby facilitating more accurate predictions of the in vivo susceptibility of S. aureus to phages during phage selection for therapeutic purposes. [ABSTRACT FROM AUTHOR]

The interaction of DNA with different block copolymers, namely poly (trimethylammonium chloride methacryloyoxy)ethyl)-block-poly(acrylamide), i.e., (PTEA)-b-(PAm), and poly (trimethylammonium chloride methacryloyoxy)ethyl)-block-poly(ethylene oxide), i.e., (PTEA)-b-(PEO), was studied. The nature of the cationic block was maintained fixed (PTEA), whereas the neutral blocks contained varying amounts of acrylamide or (ethylene oxide) units. According to results from isothermal titration microcalorimetry measurements, the copolymers interaction with DNA is endothermic with an enthalpy around 4.0 kJ mol−1 of charges for (PTEA)-b-(PAm) and 5.5 kJ mol−1 of charges for (PTEA)-b-(PEO). The hydrodynamic diameters of (PTEA)-b-(PEO)/DNA and (PTEA)-b-(PAm)/DNA polyplexes prepared by titration were around 200 nm at charge ratio (Z+/−) < 1. At Z+/− close and above 1, the (PTEA)50-b-(PAm)50/DNA and (PTEA)50-b-(PAm)200/DNA polyplexes precipitated. Interestingly, (PTEA)50-b-(PAm)1000/DNA polyplexes remained with a size of around 300 nm even after charge neutralization, probably due to the size of the neutral block. Conversely, for (PTEA)96-b-(PEO)100/DNA polyplexes, the size distribution was broad, indicating a more heterogeneous system. Polyplexes were also prepared by direct mixture at Z+/− of 2.0, and they displayed diameters around 120–150 nm, remaining stable for more than 10 days. Direct and reverse titration experiments showed that the order of addition affects both the size and charge of the resulting polyplexes. [ABSTRACT FROM AUTHOR]

The high affinity and/or selectivity of oligonucleotide-mediated binding offers a myriad of therapeutical and analytical applications, whose rational design implies an accurate knowledge of the involved molecular mechanisms, concurring equilibrium processes and key affinity parameters. Oligonucleotide-functionalized gold surfaces or nanostructures are regularly employed analytical platforms for the development of label-free optical or electrochemical biosensors, and recently, novel detection platform designs have been increasingly considering the synergistic effect of polyvalent binding, involving the simultaneous interaction of two or several oligonucleotide strands. Considering the general lack of studies involving ternary single-stranded DNA (ssDNA) interactions, a complementary analytical workflow involving capillary gel electrophoretic (CGE) mobility shift assay, microcalorimetry and computational modeling has been deployed for the characterization of a series of free and surface-bound binary and ternary oligonucleotide interactions. As a proof of concept, the DNA analogue of MicroRNA 21 (miR21), a well-known oncogenic short MicroRNA (miRNA) sequence, has been chosen as a target molecule, simulating limiting-case scenarios involved in dual molecular recognition models exploited in affinity (bio)sensing. Novel data for the characterization of oligonucleotide interacting modules is revealed, offering a fast and complete mapping of the specific or non-specific, often competing, binary and ternary order interactions in dynamic equilibria, occurring between various free and metal surface-bound oligonucleotides. [ABSTRACT FROM AUTHOR]

This work reports on the production of acrolein by oxidative coupling of biosourced alcohols (methanol and ethanol). This reaction is performed in a two-step process using iron molybdate catalyst to produce formaldehyde and acetaldehyde and zinc and cobalt aluminate spinels, with or without vacancies, to perform the cross-aldolization of aldehydes. In this study, adsorption microcalorimetry of NH 3 and SO 2 was used to determine the acid-base properties of the catalysts. The catalytic activity was monitored and correlated to catalysts acid-base properties. Moreover, to enlighten the behavior of reactants over the surface and the mechanism of the reaction, an extensive adsorption microcalorimetric study using acetaldehyde and formaldehyde as probe molecules was performed to determine molar enthalpies, molar entropies, thermokinetic parameters but also energy spectra. This broad calorimetric study provided a better understanding of the reaction and allowed to confirm the preferential adsorption of formaldehyde compared to acetaldehyde thus justifying the absence of crotonaldehyde in the products of the catalytic reaction. [Display omitted] • Acrolein is produced from bio-alcohols using zinc or cobalt aluminate spinels. • Extensive adsorption calorimetry study was performed to enlighten reaction mechanism. • Acid-base properties were correlated to acrolein yield and COx production. • Adsorption calorimetry allowed to confirm preferential formaldehyde adsorption. • The preferential formaldehyde adsorption explained the absence of crotonaldehyde. [ABSTRACT FROM AUTHOR]

A thermodynamic and kinetic study of the dissolution properties of urea phosphate (UP) in water is performed using a Calvet type microcalorimeter. Calorimetric measurements reveal the dissolution is endothermic and the heat is perfectly proportional to the amount of UP dissolved, yielding an enthalpy of (33.755 ± 0.65) kJ/mol. By combining the enthalpy data of our measurements and literature, we derive the enthalpies of urea‐phosphoric acid adduct reaction, formation of solid UP and UP dissociation. Dissolution kinetics parameters are estimated using the collected dynamic calorimetric data that are well represented with quasi‐second‐order kinetic model, giving an activation energy of (16.7 ± 2.7) kJ/mol. Thermodynamic modeling of the pH difference between UP and phosphoric acid solutions shows the degree of UP dissociation decreases from 74% to 42% when UP molality increases from 0.02 to 1 mol/kg. Furthermore, the species molality distributions in UP solutions are calculated based on mass balance and the dissociation equilibrium relations considered. [ABSTRACT FROM AUTHOR]

The effect of the microencapsulation by spray drying of the biocontrol agent Meyerozyma guilliermondii was evaluated by isothermal microcalorimetry (IMC) and traditional microbiological methods. The concentration of wall materials (soy protein isolate and sodium alginate) and inlet air temperature of the spray dryer were evaluated on the yeast viability, release rate and inhibition of Colletotrichum gloeosporioides. The parameters obtained by IMC such as maximum growth rate, lag phase time, total heat produced and the time to peak obtained from the heat flow curves were also analysed. The results showed an effect of the inlet air temperature and SPI concentration on the patterns of the heat flow curves vs. time, as well as in the kinetic parameters obtained from them. An inversely proportional correlation was found between the lag phase time and the parameters of release rate and percentage of mycelial growth inhibition. The total heat produced and the maximum growth rate was correlated with the percentage of inhibition. Likewise, the total heat produced was also correlated with the release rate. In this study, we found that higher activity of the yeast (measured in terms of heat produced and maximum growth rate by IMC) indicates a higher antifungal activity against C. gloeosporioides. [ABSTRACT FROM AUTHOR]

A thermochemical study of 2-amino-1,3,4-thiadiazole, 2-amino-5-methyl-1,3,4-thiadiazole and 2-amino-5-ethyl-1,3,4-thiadiazole has been performed, aiming to establish possible correlations between energetic properties and structural characteristics of these compounds, as well as to assess to their thermodynamic stability. Calorimetric techniques (rotating bomb combustion calorimetry and Calvet microcalorimetry) complemented with a mass loss effusion method and computational calculations were used to determine the standard molar enthalpies of formation, in the gaseous phase, at T = 298.15 K, of the three thiadiazole derivatives. Theoretical calculations at the G3(MP2)//B3LYP level of theory were also performed to obtain the enthalpies of hypothetical reactions in the gaseous phase, as well as to calculate the gas-phase enthalpy of formation for the three thiadiazoles. From the two sets of results, it is possible to make a comparison between the experimental and computational values of the gas-phase enthalpy of formation. The standard Gibbs energies of formation in the crystalline and gaseous phases were also calculated, in order to evaluate the relative thermodynamic stability of the compounds. Additionally, a tautomeric analysis of the structure of each compound was performed, resulting in the establishment of a relationship between energy versus structure of the respective tautomeric forms. [ABSTRACT FROM AUTHOR]

• The growth of P. aeruginosa was analyzed under exposure to some TiCl 4 solutions. • The solutions of TiCl 4 ranged from 0 to 10 mM and a saturated solution. • The temperature and pH of each sample were measured. • The effect of bacterial inhibition was defined. • The results support the potential use of TiCl 4 in surgical implants. With the rising use of metallic implants worldwide, bacterial infection has become a major concern due to its significant impact on patient health and national healthcare budgets. This study aimed to evaluate the sensitivity of Pseudomonas aeruginosa , a common bacterium responsible for implant surgery infections, to different concentrations of titanium tetrachloride (TiCl 4) solutions. Microcalorimetry was used to analyze the heat output produced by bacteria metabolism when exposed to TiCl 4 at concentrations ranging from 0 to 10 mM, as well as a saturated solution. The inner chamber of the calorimeter was set to the physiological temperature of the human body (309.65 K), and the heat output produced by bacteria metabolism was collected at intervals of 22.2 s for 48 h using a data acquisition and processing system. The data was then represented as thermograms. The results showed that higher concentrations of TiCl 4 had a bactericidal effect on the growth of Pseudomonas aeruginosa. This study supports the potential use of higher concentrations of this compound in surgical implants to reduce the risk of infection development due to its bactericidal properties. [ABSTRACT FROM AUTHOR]

We present a methodology for absolute activity counting of long-lived isotopes based on cryogenic Decay Energy Spectroscopy. A 146Sm source was produced at the TRIUMF Laboratory and then processed and purified at Lawrence Livermore National Laboratory, yielding a pure sample. The source was embedded within a 4 π thermal absorber coupled to a magnetic microcalorimeter achieving nearly 100% counting efficiency. Experimental uncertainties were studied and modeled, including thermal coupling of the source to the absorber, pulse pile-up, trigger, and event selection efficiencies. The absolute activity of the pure 146Sm source was measured to better than 1% uncertainty. [ABSTRACT FROM AUTHOR]

A novel bacteriophage CUB19 specific to the bacterial species Stenotrophomonas maltophilia was isolated from hospital sewage and characterized as a new species belonging to a proposed new phage genus 'Cubvirus' (Caudoviricetes). Its genome contains a total of 48,301 bp and 79 predicted genes, among which some have been associated with packaging and lysis-associated proteins, structural proteins, or DNA- and metabolism-associated proteins. No lysogeny-associated proteins or known virulence proteins were identified on the phage genome. CUB19 showed stability over a wide range of temperatures (−20 °C–60 °C) and pH values (pH 3–pH 13). Despite its narrow host range, this phage has potent observed antimicrobial and antibiofilm activity. A time-killing curve assay showed significant biofilm reduction after 24 h exposure to CUP19. Isothermal microcalorimetry assays investigating phage-antibiotic combinations revealed the effectiveness of CUB19 during co-administration with increasing antibiotic doses, regardless of the administration approach (simultaneous or staggered). These are encouraging indications for its application as a targeted therapeutic agent against resilient biofilm-associated Stenotrophomonas infections. [ABSTRACT FROM AUTHOR]

Refining the energetic costs of cellular maintenance is essential for predicting microbial growth and survival in the environment. Here, we evaluate a simple batch culture method to quantify energy partitioning between growth and maintenance using microcalorimetry and thermodynamic modeling. The constants derived from the batch culture system were comparable to those that have been reported from meta‐analyses of data derived from chemostat studies. The model accurately predicted temperature‐dependent biomass yield and the upper temperature limit of growth for Desulfovibrio alaskensis G20, suggesting the method may have broad application. An Arrhenius temperature dependence for the specific energy consumption rate, inferred from substrate consumption and heat evolution, was observed over the entire viable temperature range. By combining this relationship for specific energy consumption rates and observed specific growth rates, the model describes an increase in nongrowth associated maintenance at higher temperatures and the corresponding decrease in energy available for growth. This analytical and thermodynamic formulation suggests that simply monitoring heat evolution in batch culture could be a useful complement to the recognized limitations of estimating maintenance using extrapolation to zero growth in chemostats. [ABSTRACT FROM AUTHOR]

Ionic liquids are playing an increasingly relevant role in green chemistry due to one of their main important characteristic, their negligible vapour pressure, which means they are non-contaminant (o harmless) to the atmosphere. Nevertheless, they could be toxic for terrestrial ecosystems and therefore research to assess its toxicity to aquatic and terrestrial environments should be performed to assess whether they are as innocuous as sometimes assumed. The 1,3 dimethylimidazolium dimethylphospate, [C1C1Im][DMP], is an imidazolium ionic liquid with potential use in several industrial applications. Thus estimating the toxicity of this compound to these terrestrial ecosystems is of priority. In this study, we investigated the impact of different amounts of 1,3-dimethylimidazolium dimethyl phosphate ([C1C1Im][DMP]) on soil microbial activity by using two different methods: isothermal microcalorimetry and the classical method for measuring basal soil respiration. The aims of the study were to estimate the toxicity of this compound to soil microorganisms, to assess whether both methods were equally sensitive to estimate the impact of this ionic liquid on soil microbial activity and to combine the information obtained by both methods to obtain a more insightful picture of the impact of this compound on soil microbial activity. [ABSTRACT FROM AUTHOR]

Based on the flotation test of copper zinc sulfide ore, the effect of sodium hexametaphosphate on chalcopyrite and sphalerite was investigated by combining microcalorimetry and adsorption amount test, aiming to explain the inhibition mechanism of sodium hexametaphosphate from the perspective of thermodynamics and provide a basis for the efficient flotation separation of copper zinc sulfide ore. The results showed that the concentration of 2X 10-4 mol/L sodium hexametaphosphate at pH = 9 had a good separation effect on chalcopyrite and Cu2+ activated sphalerite,and the flotation recovery of Cu2+ activated sphalerite was reduced from 85.13% to 28. 51 %, and the recovery of chalcopyrite was reduced from 95. 15% to 90. 77%. Before the action of sodium hexametaphosphate, the apparent activation energy Ea of sodium diethyldi thiocarbamate with chalcopyrite and Cu2+ activated sphalerite were 36. 95 kJ/mol and 57. 28 kJ/mol, respectively; after the action of sodium hexametaphosphate, the apparent activation energy Ea of sodium diethyldi thiocarbamate adsorbed on the surface of chalcopyrite and Cu2+ activated sphalerite increased by 13. 07% and 37. 08%,respectively? which increased the apparent activation energy of sodium diethyldi thiocarbamate on the surface of Cu2+ activated sphalerite and Cu2+ activated sphalerite. The adsorption difficulty of ethionite on Cu2+ activated sphalerite surface was increased by 13. 07% and 37. 08%, respectively, which increased the difficulty of ethionite adsorption on Cu2+ activated sphalerite surface, while it had less effect on ethionite adsorption on chalcopyrite surface. [ABSTRACT FROM AUTHOR]

Self-ignited fires at municipal solid waste (MSW) storage sites are relatively common. The minimization of the phenomenon of self-heating in the waste can reduce the risks for smouldering combustion. The purpose of this work was to develop a method that can be used to measure and characterize the heat production in MSW. The method is based on isothermal heat conduction microcalorimetry (IMC). The heat production in MSW was determined based on sampling from two sites in two different geographical locations in Sweden. Both the original waste and milled/homogenised waste were tested. The heat production was measured at different temperatures together with gas analysis using micro-gas chromatography. The activity in the waste, in terms of its heat flow, increased when the temperature increased up to 60 °C and decreased at higher temperatures, e.g., 70 and 80 °C. The consumption of oxygen and the production of carbon dioxide, together with the heat production, indicated that aerobic metabolism was responsible for the heat production. This is further strengthened by the marginal heat production observed for ultraviolet treated waste. The results showed that IMC is a valuable tool for characterising the self-heating in municipal and industrial waste. [ABSTRACT FROM AUTHOR]

Background: A consensus definition recently was formulated for fracture-related infection, which centered on confirmatory criteria including conventional cultures that take time to finalize and have a 10% to 20% false-negative rate. During this time, patients are often on broad-spectrum antibiotics and may remain hospitalized until cultures are finalized to adjust antibiotic regimens.Questions/purposes: (1) What is the diagnostic accuracy of isothermal microcalorimetry, and how does its accuracy compare with that of conventional cultures? (2) Does isothermal microcalorimetry decrease time to detection (or diagnosis) of fracture-related infection compared with conventional cultures? (3) Does isothermal microcalorimetry have a diagnostic accuracy or time advantage over conventional cultures in patients on chronic suppressive antibiotics?Methods: Between July 2020 and August 2021, we treated 310 patients with concerns for infection after prior fracture repair surgery. Of those, we considered all patients older than 18 years of age with fixation hardware in place at the time of presentation as potentially eligible. All included patients returned to the operating room with cultures obtained and assessed by both isothermal microcalorimetry and conventional cultures, and all were diagnosed using the consensus criteria for fracture-related infection. Based on that, 81% (250 of 310) of patients were eligible; a further 51% (157 of 310) were excluded because of the following reasons: the capacity of the isothermal microcalorimetry instrument limited the throughput on that day (34% [106 of 310]), they had only swab cultures obtained in surgery (15% [46 of 310]), or they had less than 3 months follow-up after surgery for infectious concerns (2% [5 of 310]), leaving 30% (93 of 310) of the originally identified patients for analysis. We obtained two to five cultures from each patient during surgery, which were sent to our clinical microbiology laboratory for standard processing (conventional cultures). This included homogenization of each tissue sample individually and culturing for aerobic, anaerobic, acid-fast bacilli, and fungal culturing. The remaining homogenate from each sample was then taken to our orthopaedic research laboratory, resuspended in growth media, and analyzed by isothermal microcalorimetry for a minimum of 24 hours. Aerobic and anaerobic cultures were maintained for 5 days and 14 days, respectively. Overall, there were 93 patients (59 males), with a mean age of 43 ± 14 years and a mean BMI of 28 ± 8 kg/m 2 , and 305 tissue samples (mean 3 ± 1 samples per patient) were obtained and assessed by conventional culturing and isothermal microcalorimetry. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of isothermal microcalorimetry to diagnose fracture-related infection were compared with conventional cultures using a McNemar test based on the consensus definition of fracture-related infection. This consensus criteria is comprised of two levels of certainty for the diagnostic variables. The first is confirmatory criteria, where infection is considered definitely present and includes the presence of fistula/sinus tract/wound breakdown, purulent drainage or the presence of pus, presence of microorganisms in deep tissue specimens on histopathologic examination, presence of more than five neutrophils/high-powered field by histopathologic examination (only for chronic/late onset cases), and identification of phenotypically indistinguishable pathogens by conventional culture from at least two separate deep tissue/implant specimens. The second is suggestive criteria in which further investigation is required to achieve confirmatory status. Fracture-related infection was diagnosed for this study to minimize subjectivity based on the presence of at least one of the confirmatory criteria as documented by the managing surgeon. When suggestive criteria were present without confirmatory criteria, patients were considered negative for fracture-related infection and followed further in clinic after surgical exploration (n = 25 patients). All 25 patients deemed not to have fracture-related infection were considered infection-free at latest follow-up (range 3 to 12 months). The time to detection or diagnosis was recorded and compared via the Mann-Whitney U test.Results: Using the consensus criteria for fracture-related infection, there were no differences with the numbers available between isothermal microcalorimetry and conventional cultures in terms of sensitivity (87% [95% confidence interval 77% to 94%] versus 81% [95% CI 69% to 89%]), specificity (100% [95% CI 87% to 100%] versus 96% [95% CI 79% to 99%]), PPV (100% [95% CI 90% to 100%] versus 98% [95% CI 89% to 99%]), NPV (74% [95% CI 60% to 84%] versus 65% [95% CI 52% to 75%]), or accuracy (90% [95% CI 83% to 96%] versus 85% [95% CI 76% to 91%]; p = 0.13). The concordance by sample between conventional cultures and isothermal microcalorimetry was 85%. Isothermal microcalorimetry had a shorter median (range) time to detection or diagnosis compared with conventional cultures (2 hours [0.5 to 66] versus 51 hours [18 to 147], difference of medians 49 hours; p < 0.001). Additionally, 32 patients used antibiotics for a median (range) duration of 28 days (7 to 1095) before presentation. In these unique patients, there were no differences with the numbers available between isothermal microcalorimetry and conventional cultures in terms of sensitivity (89% [95% CI 71% to 98%] versus 74% [95% CI 53% to 88%]), specificity (100% [95% CI 48% to 100%] versus 83% [95% CI 36% to 99%]), PPV (100% [95% CI 85% to 100%] versus 95% [95% CI 77% to 99%]), NPV (63% [95% CI 37% to 83%] versus 42% [95% CI 26% to 60%]), or accuracy (91% [95% CI 75% to 98%] versus 78% [95% CI 57% to 89%]; p = 0.17). Isothermal microcalorimetry again had a shorter median (range) time to detection or diagnosis compared with conventional cultures (1.5 hours [0.5 to 48] versus 51.5 hours [18 to 125], difference of medians 50 hours; p < 0.001).Conclusion: Given that isothermal microcalorimetry considerably decreases the time to the diagnosis of a fracture-related infection without compromising the accuracy of the diagnosis, managing teams may eventually use isothermal microcalorimetry-pending developmental improvements and regulatory approval-to rapidly detect infection and begin antibiotic management while awaiting speciation and susceptibility testing to modify the antibiotic regimen. Given the unique thermograms generated, further studies are already underway focusing on speciation based on heat curves alone. Additionally, increased study sizes are necessary for both overall fracture-related infection diagnostic accuracy and test performance on patients using long-term antibiotics given the promising results with regard to time to detection for this groups as well.Level Of Evidence: Level II, diagnostic study. [ABSTRACT FROM AUTHOR]

Isothermal microcalorimetry is used to study the heat flow of lithium-ion cells to provide insight into active material characteristics and to provide data required for a thermal optimization on the cell and system level. Recent research has shown the application of this technique to cells during high cycling rates, for example fast charging. However, the limitation of isothermal microcalorimetry is the low-pass characteristic of the measured heat flow, introduced by the thermal inertia of the setup and the calorimeter itself. To solve this problem, we introduce an optimized cell holder design and a novel data processing method for a time-resolved measurement of highly dynamic heat flow profiles. These are described in detail and validated using a synthetic power profile applied to a dummy cell. Experiments on a graphite-lithium half-cell illustrate the improvement of the method and the optimized cell holder when compared to the state-of-the-art setup, demonstrating the 3.6 times faster time response, which was further improved using a post-processing deconvolution technique. The thus improved time resolution provides the acquisition of more detailed features than currently shown in the literature and allows an accurate correlation of the thermal signals to electrochemical features like, e.g., the differential voltage of the cell. [ABSTRACT FROM AUTHOR]

Abstract In this communication, sulfate dodecyl sodium (SDS)-induced thermodynamics and conformational changes of collagen were studied. We used ultrasensitive differential scanning calorimetry (US-DSC) to directly monitor the thermal transition of collagen in the presence of SDS. The results show that SDS affects the conformation and thermal stability of collagen very differently depending on its concentrations. At CSDS ≤ 0.05 mM, the enhanced thermal stability of collagen indicates the stabilizing effect by SDS. However, a further increase of SDS leads to the denaturation of collagen, verifying the well-known ability of SDS to unfold proteins. This striking difference in thermodynamics and conformational changes of collagen caused by SDS concentrations can be explained in terms of their interactions. With increasing SDS, the binding of SDS to collagen can be dominated by electrostatic interaction shifting to hydrophobic interaction, and the latter plays a key role in loosening and unfolding the triple-helix structure of collagen. The important finding in the present study is the stabilizing effect of SDS on collagen molecules at extreme low concentration. Graphical abstract