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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]

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]

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]

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]

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]

Summary: The detection and quantification of Legionella pneumophila (responsible for legionnaire's disease) in water samples can be achieved by various methods. However, the culture‐based ISO 11731:2017, which is based on counts of colony‐forming units per ml (CFU·ml‐1) is still the gold standard for quantification of Legionella species (spp.). As a powerful alternative, we propose real‐time monitoring of the growth of L. pneumophila using an isothermal microcalorimeter (IMC). Our results demonstrate that, depending on the initial concentration of L. pneumophila, detection times of 24–48 h can be reliably achieved. IMC may, therefore, be used as an early warning system for L. pneumophila contamination. By replacing only visual detection of growth by a thermal sensor, but otherwise maintaining the standardized protocol of the ISO 11731:2017, the new procedure could easily be incorporated into existing standards. The exact determination of the beginning of metabolic heat is often very difficult because at the beginning of the calorimetric signal the thermal stabilization and the metabolic heat development overlap. Here, we propose a new data evaluation based on the first derivation of the heat flow signal. The improved evaluation method can further reduce detection times and significantly increase the reliability of the IMC approach. [ABSTRACT FROM AUTHOR]

The larvae of Hermetia illucens are known to successfully bio‐convert a vast range of organic substrates into high protein and fat biomass, but little is known about the larval instars. During this research, larval head capsules and biomass growth were measured daily and the specific metabolic rate of larger instars were considered. The head capsule measurements revealed that H. illucens pass through 6 actively feeding larval stadia before entering the last nonfeeding but migrating 7th stadium. Larval growth follows a sigmoid curve with slowly accelerating growth in the earlier stadia and decelerating growth in the latest stadia. In contrast, development was fast until reaching stadium 6 and then slowed down. Accordingly, the specific metabolic rate was high in instars 3, 4 and 5 and reduced in instars 6 and 7. [ABSTRACT FROM AUTHOR]

Understanding the determinants of metabolism is a core ecological topic since it permits to link individual energetic requirements to the ecology of communities and ecosystems. Yet, besides temperature, metabolic responses to environmental factors remain poorly understood. For example, it is commonly assumed that dietary stoichiometric constraints increase metabolism of small invertebrates despite scarce experimental support. Here, we used microcalorimetric measurements to determine the standard metabolic rate (SMR) of Daphnia magna fed stoichiometrically balanced (C/P: 166) or imbalanced (C/P: 1439). Daphnids fed imbalanced maintained their stoichiometric homeostasis within narrow boundaries. However, they consistently increased their SMR while decreasing their growth rate. Our measurements demonstrate that homeostatic regulation implies higher metabolic costs, thereby reducing available energy for growth. We demonstrate that microcalorimetry is a powerful and precise tool for measuring small‐sized organisms' metabolic rate, thus opening promising perspectives for understanding how environmental factors, such as nutritional constraints, affect organismal metabolism. [ABSTRACT FROM AUTHOR]

Primary aim of this in vitro study was to test the efficacy of daptomycin to eradicate staphylococcal biofilms on various orthopedic implant materials. Secondary aim was to quantitatively estimate the formation of staphylococcal biofilm. We tested six clinically important biomaterials: Cobalt chrome, pure titanium, grid‐blasted titanium, porous plasma‐coated titanium with/without hydroxyapatite, and polyethylene. Biofilms of S. aureus and S. epidermidis were formed on the samples and thereafter exposed to daptomycin. Samples were subsequently sonicated in order to detect dislodged biofilm bacteria and transferred to a microcalorimeter for real‐time measurement of growth‐related heat flow. Minimal biofilm eradication concentration (MBEC) was determined as the lowest concentration of daptomycin required to eradicate biofilm bacteria on the sample. Median MBEC of S. aureus biofilm on smooth metallic surfaces was lower than the rough metallic surfaces. In experiments with S. epidermidis, no pattern was seen in relation to the surface roughness. Regarding the quantitative estimation of staphylococcal biofilm formation on the sample, we found a significantly higher amount of biofilm growth on the rough surfaces than the smooth samples and polyethylene. In conclusion, the presented study showed that daptomycin could eradicate S. aureus biofilm at lower concentrations on the smooth surfaces compared to the rough surfaces, as well as polyethylene. In experiments with daptomycin against S. epidermidis biofilms, no pattern was seen in relation to the surface roughness. Furthermore, we demonstrated a faster detection of staphylococcal heat flow due to higher biofilm quantity on the rough surfaces compared to smooth samples and polyethylene. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2809–2816, 2018. This study of staphylococcal biofilm formation and eradication on various orthopedic implant materials showed that daptomycin could eradicate S. aureus biofilm at lower concentrations on the smooth surfaces compared to the rough surfaces, as well as polyethylene. In experiments with daptomycin against S. epidermidis biofilms, no pattern was seen in relation to the surface roughness. Furthermore, we demonstrated a faster detection of staphylococcal heat flow due to higher biofilm quantity on the rough surfaces compared to smooth samples and polyethylene. [ABSTRACT FROM AUTHOR]

ABSTRACT: A combination of microcalorimetry, the rotating sector method, and ESR at 323 K in the environment of 10 solvents of different polarities was used to measure rate constants of addition of hydroperoxide radicals ( HO 2 •) to π bonds of trans‐1,2‐diphenylethylene and trans,trans‐1,4‐diphenylbutadiene‐1,3 (k2) and disproportionation rate constants of these radicals (k3). With increasing dielectric constant of the medium, k2 values increase from 69 to 410 M−1 · s−1, and k3 values almost do not change and are in the range of (1.0 ± 0.2) × 108 M−1 · s−1. A linear dependence of logarithm values of rate constants from the dielectric constant of the medium in the coordinates of the Kirkwood–Onsager equation was found that allows to make a conclusion about the effect of nonspecific solvation in the studied systems. The quantum‐chemical analysis (NWChem, DFT B3LYP/6‐311G**) of the detailed mechanism for HO 2 • addition shows that the influence of the medium polarity reflects the superposition of the effects of nonspecific and specific solvation. The scale of the polar effect will depend on how different solvation energies of the transition and the initial reaction complexes. If a value of the solvation energy of the transition complex is larger than the solvation energy of the initial reaction complex, then the reaction rate should increase with an increase of the solvent's polarity and decrease otherwise. [ABSTRACT FROM AUTHOR]

Abstract: One of the most powerful techniques that are currently available to measure thermodynamic parameters such as enthalpy (ΔH), Gibbs free energy (ΔG), entropy changes (ΔS), and binding affinity in chemical reactions is isothermal titration calorimetry (ITC). Recent advances in instrumentation have facilitated the development of ITC as a very essential analytical tool in biology and chemistry. In this article, we will focus on a review of the literature on the application of ITC for the study of chiral systems and chiral interactions. We present studies in which the ITC technique is used to study chiral interactions, for instance in chiral solutions, chiral organometallic complexes, guest‐host chiral binding interactions, and biological macromolecules. Finally, we put strong emphasis on the most recent application of ITC for the study of chirality in nanosystems and at the nanoscale. [ABSTRACT FROM AUTHOR]

Abstract: Ammonium perchlorate(AP) and LiBH4 can form an oxidation‐fuel energetic system, which provides a new development direction in designing novel mixed explosive formula. The microcalorimetry and self‐designed slow cook‐off setup were used to study thermal performance of AP/LiBH4 energetic powders and grains respectively. Experimental results show that heat release in microcalorimetry method for the mixed system at low temperature was due to the reaction between LiBH4 and residual water vapour. The oxidant gases from AP decomposition participate in the oxidation of LiBH4 at high temperature. The ignition temperature for the AP/LiBH4 grain was 270 °C and the explosion reactions were violent in slow cook‐off test. [ABSTRACT FROM AUTHOR]

The self-assembly of short peptide offers versatile processes for adjusting the ordered stacking of organic functional materials to enhance photoinduced electron transfer. Herein, this study presents the first demonstration of the use of Aβ16-22 peptide to prepare polythiophene/Aβ16-22 assemblies for a photocatalytic water splitting system. Isothermal titration microcalorimetry results show that the driving forces for polythiophene/Aβ16-22 assembly formation are electrostatic interactions, as well as hydrogen bonds and hydrophobic interactions. The assemblies accelerate the photoinduced electrons transfer from polythiophene upon light excitation and eventually enhance the hydrogen evolution. This work opens a new way into the development of biohybrid materials as novel photocatalytic water splitting platform for hydrogen evolution. [ABSTRACT FROM AUTHOR]

Key points Heat associated with muscle shortening has been repeatedly demonstrated in skeletal muscle, but its existence in cardiac muscle remains contentious after five decades of study., By iterating between experiments and computational modelling, we show compelling evidence for the existence of shortening heat in cardiac muscle and reveal, mechanistically, the source of this excess heat., Our results clarify a long-standing uncertainty in the field of cardiac muscle energetics., We provide a revised partitioning of cardiac muscle energy expenditure to include this newly revealed thermal component., Abstract When a muscle shortens against an afterload, the heat that it liberates is greater than that produced by the same muscle contracting isometrically at the same level of force. This excess heat is defined as 'shortening heat', and has been repeatedly demonstrated in skeletal muscle but not in cardiac muscle. Given the micro-structural similarities between these two muscle types, and since we imagine that shortening heat is the thermal accompaniment of cross-bridge cycling, we have re-examined this issue. Using our flow-through microcalorimeter, we measured force and heat generated by isolated rat trabeculae undergoing isometric contractions at different muscle lengths and work-loop (shortening) contractions at different afterloads. We simulated these experimental protocols using a thermodynamically constrained model of cross-bridge cycling and probed the mechanisms underpinning shortening heat. Predictions generated by the model were subsequently validated by a further set of experiments. Both our experimental and modelling results show convincing evidence for the existence of shortening heat in cardiac muscle. Its magnitude is inversely related to the afterload or, equivalently, directly related to the extent of shortening. Computational simulations reveal that the heat of shortening arises from the cycling of cross-bridges, and that the rate of ATP hydrolysis is more sensitive to change of muscle length than to change of afterload. Our results clarify a long-standing uncertainty in the field of cardiac muscle energetics. [ABSTRACT FROM AUTHOR]

The impact of acid/base properties (determined by adsorption microcalorimetry) of various catalysts on the cross-aldolization of acetaldehyde and formaldehyde leading to acrolein was methodically studied in oxidizing conditions starting from a mixture of methanol and ethanol. The aldol condensation and further dehydration to acrolein were carried out on catalysts presenting various acid/base properties (MgO, Mg-Al oxides, Mg/SiO2, NbP, and heteropolyanions on silica, HPA/SiO2). Thermodynamic calculations revealed that cross-aldolization is always favored compared with self-aldolization of acetaldehyde, which leads to crotonaldehyde formation. The presence of strong basic sites is shown to be necessary, but a too high amount drastically increases CO x production. On strong acid sites, production of acrolein and carbon oxides (CO x) does not increase with temperature. The optimal catalyst for this process should be amphoteric with a balanced acid/base cooperation of medium strength sites and a small amount (<100 μmol g−1) of very strong basic sites ( Qdiff>150 kJ mol−1). [ABSTRACT FROM AUTHOR]

Food allergies are recognized as an increasing health concern. Proteins commonly identified as food allergens tend to have one of about 30 different biochemical activities. This leads to the assumption that food allergens must have specific structural features which causes their allergenicity. But these structural features are not completely understood. Uncovering the structural basis of allergenicity would allow improved diagnosis and therapy of allergies and would provide insights for safer food production. The availability of recombinant food allergens can accelerate their structural analysis and benefit specific studies in allergology. Plant chitinases are an example of food allergenic proteins for which structural analysis of allergenicity has only partially been reported. The recombinant maize chitinase, rChiA, was purified from Pichia pastoris extracellular medium by differential precipitation and cation exchange chromatography. Enzyme activity was evaluated by halo-assays and microcalorimetric procedures. rChiA modeling was performed by a two-step procedure, using the Swiss-Model server and Modeller software. Allergenicity of rChiA was verified by immunoblot assays with sera from allergic subjects. rChiA is active in the hydrolysis of glycol chitin and tetra-N-acetylchitotetraose and maintains its activity at high temperatures (70°C) and low pH ( pH 3). The molecule is also reactive with IgE from sera of maize-allergic subjects. rChiA is a valuable molecule for further studies on structure-allergenicity relationships and as a tool for diagnosing allergies. [ABSTRACT FROM AUTHOR]

This work reported the adsorption and reaction performance of FeOx supported subnanometer cluster and single-atom Ir catalysts for the oxidation of CO at low temperature. By varying the pretreatment temperature and Ir loading, the single-atom and subnanometer cluster Ir catalysts were obtained. The Ir subnanometer clusters exhibited higher activity for the oxidation of CO with or without the presence of H2 than the single-atom counterpart. By using adsorption microcalorimetry and in situ infrared spectroscopy measurements, it was found that the Ir subnanometer clusters not only promoted the adsorption and reaction of CO and O2 but also facilitated the formation of OH species from reaction between H2 and O2, thus opening a new reaction pathway between CO and OH species to produce CO2 compared with that between CO and O species on the single-atom counterpart. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4003-4012, 2017 [ABSTRACT FROM AUTHOR]

The energetic or adhesive interaction between binder matrix and solid fillers as well as plasticizers and fillers is a property determining mechanical properties as strain capacity and stress at maximum or stress at break. To know such interaction energies is therefore of interest. An isoperibolic solution calorimeter is used to measure such interaction energies or heats of immersion of the solid propellant components ammonium perchlorate (AP) and aluminium (AL) with the liquid plasticizers bis-(2-ethylhexyl) adipate (DEHA) and azido-terminated oligomeric glycidylazide (GAP−A). The determined heats indicate wettability and interaction energy in units of energy per surface area of the solid component. For AP, three different grain sizes with mean diameter about 200, 90, 42 μm were used. Results indicate dependence of AP wetting on mean particle diameter: Successful wetting occurs for AP at diameters from above 90 μm. The polar interactions between the ionic AP and GAP−A greatly enhance wetting as compared to DEHA. [ABSTRACT FROM AUTHOR]

Endospores of anaerobic thermophilic bacteria (thermospores) are ubiquitous in cold marine sediments. These misplaced thermophiles likely originate from warm environments and are delivered to the seafloor by passive dispersal through the water column. The few studies of the abundance of thermospores that exist have only quantified a subset of the anaerobic metabolic types possibly present and the data density has been too low to address patterns of dispersal. Here, we introduce isothermal microcalorimetry as a fast tool to quantify the abundance of thermospores in environmental samples. We developed and tested the method on samples from the water column and sediment of Aarhus Bay, Denmark. The thermospores were stimulated to germinate and grow by heating the samples to 50°C inside an isothermal microcalorimeter and the metabolic heat production was followed across the exponential growth phase. The number of germinated thermospores was then calculated by dividing the total heat production rate by the cell specific heat production rate, empirically determined in parallel experiments. The abundance of thermospores in the water column of Aarhus Bay was 1.2 × 103−3.6 × 103 cells × mL−1 seawater. The abundance of thermospores in sediment in Aarhus Bay was 1.1 × 106−6.1 × 106 cells × mL−1 sediment and their half-life was ∼70 yr. As application example we used isothermal microcalorimetry to test if thermospores were aggregated at a pockmark in Limfjorden (Denmark) with seepage of thermogenic gas and oil. [ABSTRACT FROM AUTHOR]

Oxidative coupling of methanol and ethanol represents a new route to produce acrolein. In this work, the overall reaction was decoupled in two steps, the oxidation and the aldolization, by using two consecutive reactors to investigate the role of the acid/base properties of silica-supported oxide catalysts. The oxidation of a mixture of methanol and ethanol to formaldehyde and acetaldehyde was performed over a FeMoO x catalyst, and then the product mixture was transferred without intermediate separation to a second reactor, in which the aldol condensation and dehydration to acrolein were performed over the supported oxides. The impact of the acid/base properties on the selectivity towards acrolein was investigated under oxidizing conditions for the first time. The acid/base properties of the catalysts were investigated by NH3-, SO2-, and methanol-adsorption microcalorimetry. A MgO/SiO2 catalyst was the most active in acrolein production owing to an appropriate ratio of basic to acidic sites. [ABSTRACT FROM AUTHOR]

The interaction of sodium dodecyl sulfate (SDS) with poly(4-vinylpyridine N-oxide) (PVPNO) at different pH values and ionic strengths has been studied by isothermal titration microcalorimetry, electrical conductivity and turbidity measurements. The solution pH significantly effects the formation of the PVPNO/SDS complex. At pH 1.5, the polymer PVPNO is a strong polycation, and the binding is dominated by electrostatic 1:1 charge neutralization with the anionic surfactant. At pH 6 and 8, the electrostatic attraction between SDS and PVPNO is weak, and the hydrophobic interaction becomes stronger. The effect of salt concentration on the interaction of SDS and PVPNO depends on the competition between the increase of interaction and the screening of interaction. This study based on the thermodynamic process gained deep insight into the effects of pH value and ionic strength on the interaction mechanism of surfactant with polyelectrolyte. We also constructed a simple model for the interaction of PVPNO and SDS system in different solution regions. [ABSTRACT FROM AUTHOR]

The human NAD(P)H:quinone oxidoreductase 1 ( NQO1; ) is an essential enzyme in the antioxidant defence system. Furthermore, NQO1 protects tumour suppressors like p53, p33 ING1b and p73 from proteasomal degradation. The activity of NQO1 is also exploited in chemotherapy for the activation of quinone-based treatments. Various single nucleotide polymorphisms are known, such as NQO1*2 and NQO1*3 yielding protein variants of NQO1 with single amino acid replacements, i.e. P187S and R139W, respectively. While the former NOQ1 variant is linked to a higher risk for specific kinds of cancer, the role, if any, of the arginine 139 to tryptophan exchange in disease development remains obscure. On the other hand, mitomycin C-resistant human colon cancer cells were shown to harbour the NQO1*3 variant resulting in substantially reduced enzymatic activity. However, the molecular cause for this decrease remains unclear. In order to resolve this issue, recombinant NQO1 R139W has been characterized biochemically and structurally. In this report, we show by X-ray crystallography and 2D- NMR spectroscopy that this variant adopts the same structure both in the crystal as well as in solution. Furthermore, the kinetic parameters obtained for the variant are similar to those reported for the wild-type protein. Similarly, thermostability of the variant was only slightly affected by the amino acid replacement. Therefore, we conclude that the previously reported effects in human cancer cells cannot be attributed to protein stability or enzyme activity. Instead, it appears that loss of exon 4 during maturation of a large fraction of pre- mRNA is the major reason of the observed lack of enzyme activity and hence reduced activation of quinone-based chemotherapeutics. [ABSTRACT FROM AUTHOR]

Managing trade-offs through gene regulation is believed to confer resilience to a microbial community in a fluctuating resource environment. To investigate this hypothesis, we imposed a fluctuating environment that required the sulfate-reducer Desulfovibrio vulgaris to undergo repeated ecologically relevant shifts between retaining metabolic independence (active capacity for sulfate respiration) and becoming metabolically specialized to a mutualistic association with the hydrogen-consuming Methanococcus maripaludis. Strikingly, the microbial community became progressively less proficient at restoring the environmentally relevant physiological state after each perturbation and most cultures collapsed within 3-7 shifts. Counterintuitively, the collapse phenomenon was prevented by a single regulatory mutation. We have characterized the mechanism for collapse by conducting RNA-seq analysis, proteomics, microcalorimetry, and single-cell transcriptome analysis. We demonstrate that the collapse was caused by conditional gene regulation, which drove precipitous decline in intracellular abundance of essential transcripts and proteins, imposing greater energetic burden of regulation to restore function in a fluctuating environment. [ABSTRACT FROM AUTHOR]

The catalytic performance of 1) crystalline MoVTeNb oxide that exhibits the electronic properties of a n-type semiconductor, 2) submonolayer vanadium oxide supported on meso-structured silica (SBA-15) as an insulating support, and 3) surface-functionalized carbon nanotubes that contain neither a redox active metal nor bulk oxygen, but only surface oxygen species have been compared in the oxidative dehydrogenation of ethane and propane under equal reaction conditions. The catalytic results indicate similarities in the reaction network over all three catalysts within the range of the studied reaction conditions implying that differences in selectivity are a consequence of differences in the rate constants. Higher activity and selectivity to acrylic acid over MoVTeNb oxide as compared to the other two catalysts are attributed to the higher density of potential alkane adsorption sites on M1 and the specific electronic structure of the semiconducting bulk catalyst. Microcalorimetry has been used to determine and quantify different adsorption sites revealing a low Vsurface/C3H8 ads ratio of 4 on M1 and a much higher ratio of 150 on silica-supported vanadium oxide. On the latter catalyst less than one per cent of the vanadium atoms adsorb propane. Barriers of propane activation increase in the order P/oCNT (139 kJ mol−1)≤M1 (143 kJ mol−1)<6V/SBA-15 (162 kJ mol−1), which is in agreement with trends predicted by theory. [ABSTRACT FROM AUTHOR]

N2O, as a green propellant alternative to N2H4, shows potential application in satellite propulsion system. The state of Ir species and the reaction behaviors on Ir/Al2O3 in the oxidative environment during N2O decomposition were identified here. Two types of Ir sites existed in this catalyst and affected the process of N2O decomposition. The strong Ir sites facilitated the dissociative adsorption of N2O to form N2 and adsorbed O atoms with adsorption heat of as high as 281 kJ/mol, which promoted the desorption of adsorbed O atoms and favored the self-sustaining decomposition of N2O by raising the catalyst bed temperature. The other Ir sites interacted weakly with O atoms but facilitated their combination to form O2. The Ir/Al2O3 catalyst then exhibited an excellent performance in initiating the decomposition of N2O at low temperature of 200°C and good stability in 0.1 N microthruster for orbit adjustment and attitude control of satellite. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3973-3981, 2016 [ABSTRACT FROM AUTHOR]

A series of four micro- or mesoporous metal-organic frameworks [UiO-66(Zr), UiO-66(Zr)_NH2, MIL-100(Fe), MIL-127(Fe)] were synthesized in powder form and pelletized in the form of spheres by using a polyvinyl-based binder. The effect of pelletization on the adsorption of a series of gasses (N2, CO, CO2, CH4, C2H6, C3H8, C3H6, C4H10) at 303 K was evidenced in the adsorption isotherms and the enthalpies of adsorption measured by using microcalorimetric analysis. As expected, uptakes of gas per gram of material were lower for the spheres than for the powder. However, taking into account the bulk density, this tendency was inverted, suggesting that the spherical materials are of distinct interest for gas-based applications. Nevertheless, other effects including partial pore restriction and active site 'protection' may equally be evidenced for some pelletized materials, suggesting that the polyvinyl binder may play a more complex role. [ABSTRACT FROM AUTHOR]

ABSTRACT In this work we have investigated the role of high molecular weight poly(ethylene-glycol) 8000 (PEG 8000) in modulating the interactions of the DNA molecule with two hydrophobic compounds: Ethidium Bromide (EtBr) and GelRed (GR). Both compounds are DNA intercalators and are used here to mimic the behavior of more complex DNA ligands such as chemotherapeutic drugs and proteins whose domains intercalate DNA. By means of single-molecule stretching experiments, we have been able to show that PEG 8000 strongly shifts the binding equilibrium between the intercalators and the DNA even at very low concentrations (1% in mass). Additionally, microcalorimetry experiments were performed to estimate the strength of the interaction between PEG and the DNA ligands. Our results suggest that PEG, depending on the system under study, may act as an 'inert polymer' with no enthalpic contribution in some processes but, on the other hand, it may as well be an active (non-neutral) osmolyte in the context of modulating the activity of the reactants and products involved in DNA-ligand interactions. © 2015 Wiley Periodicals, Inc. Biopolymers 105: 227-233, 2016. [ABSTRACT FROM AUTHOR]

The thermodynamic stability of nanocrystalline SnO2-TiO2 solid solutions was studied experimentally. Microcalorimetry of water adsorption revealed a systematic decrease in the surface energy with increasing Ti4+ content in the SnO2-rich compositions, consistent with previous reports of Ti4+ segregation on the surface. The surface energy change was accompanied by an increase in the magnitude of the heat of water adsorption, also indicating a modification of the SnO2 surface by Ti4+. Supporting the water adsorption data, calculations using high-temperature oxide melt solution calorimetry data also suggest a decrease in the interface energies. A thermodynamic analysis showed that the observed surface energy decrease is responsible for an increase in the stability of solid solutions in the nanophase regime. Although a miscibility gap is expected in this system from bulk phase diagrams, the surface energy contribution modifies the bulk trend and promotes extensive solid solutions when the surface area is above a critical value dependent on the surface energy and the bulk enthalpy of mixing. [ABSTRACT FROM AUTHOR]

The thermokinetics of the curing reactions between poly-(3-azidomethyl-3-methyloxetane) (PAMMO) and bispropargyl succinate (BPS) were studied using a microcalorimeter. On the basis of experimental and calculated results, three thermodynamics parameters (the activation enthalpies, the activation entropies, the activation free energies), the rate constant, three thermokinetic parameters (the activation energies, the pre-exponential constant, and the reaction order) and the enthalpies of the curing reactions between PAMMO and BPS in the temperature range of 50-65 °C were obtained, showing that the main reaction leading to a triazole structure easily took place in the studied temperature range. The linear relationship between ln k and the molar ratio of triple bonds to azide groups was found. Furthermore, the corresponding kinetic equation describing the curing reaction between PAMMO and BPS was d α/d t=10−4.48(1− α)0.962 at 333.15 K. [ABSTRACT FROM AUTHOR]

The surveillance of gun propellants is basically performed either by an investigation into the thermal behavior of the propellant or by the determination of its remaining effective stabilizer content. Over the years it is shown that the surveillance of NC based gun propellants is necessary. NC based materials are intrinsically unstable, and can cause many accidents. Some accidents were caused by old unstable material, other ones were initiated by the extreme conditions during storage, like during expeditionary operations of military forces. And in quite a few cases it was a combination of these. Surveillance tests have changed over the years, and the last philosophy is to test the propellants as close as possible in comparison to the way they are stored [1] for this way of testing the Heat Flow Calorimetry (or microcalorimetry) method is the optimum. Older methods like the Abel heat test, Methyl Violet Test, Bergman-Junk stability test, are test methods an analysis of the current status, without or very limited prediction behavior. Besides that the temperatures are relatively high, the measuring value is quite strongly dependent of the observer/operator. In general these tests are applied for propellants and sometimes explosives, although the general application worldwide (as far they are in use by countries) is propellants. [ABSTRACT FROM AUTHOR]

Signal transduction processes are typically initiated by the interaction of signal molecules with sensor domains. The current lack of information on the signal molecules that feed into regulatory circuits forms a major bottleneck that hampers the understanding of regulatory processes. Mc Kellar et al. report a high-throughput approach for the identification of signal molecules, which is based on thermal shift assays of recombinant sensor domains in the absence and presence of compounds from commercially available ligand collections. Initial binding studies with the sensor domain of the PctA chemoreceptor of P seudomonas aeruginosa showed a close match between thermal shift assay results and microcalorimetric studies reported previously. Using thermal shift assays the authors then identify signals that bind to three chemoreceptors of the kiwifruit pathogen P . syringae pv. Actinidiae NZ- V13. Microcalorimetric binding studies and chemotaxis assays have validated the relevance of these ligands. The power of this technique lies in the combination of a high-throughput analytical tool with commercially available compound collections. The approach reported is universal since it can be employed to identify signal molecules to any type of sensor domain. There is no doubt that this technique will facilitate the identification of many signal molecules in future years. [ABSTRACT FROM AUTHOR]

In this report, the interactions between fifteen selected ionic liquids (ILs) and cellobiose (CB) are examined by high-precision solution microcalorimetry. The heat of mixing (Δmix H) of CB and ILs, or CB and IL/molecular solvent (MS) solutions, provides the first ever-published measure of the affinity of CB with ILs. Most importantly, we found that there is a very good correlation between the nature of the results found for Δmix H(CB) and the solubility behavior of cellulose. This correlation suggests that Δmix H(CB) offers a good estimate of the enthalpy of dissolution of cellulose even in solvents in which cellulose is insoluble. Therefore, the current findings open up new horizons for unravelling the intricacies of the thermodynamic factors accounting for the spontaneity of cellulose dissolution in ILs or IL/MS solutions. [ABSTRACT FROM AUTHOR]

High-mannose-type glycans (HMTGs) decorating viral spike proteins are targets for virus neutralization. For carbohydrate-binding proteins, multivalency is important for high avidity binding and potent inhibition. To define the chemical determinants controlling multivalent interactions we designed glycopeptide HMTG mimetics with systematically varied mannose valency and spacing. Using the potent antiviral lectin griffithsin (GRFT) as a model, we identified by NMR spectroscopy, SPR, analytical ultracentrifugation, and microcalorimetry glycopeptides that fully recapitulate the specificity and kinetics of binding to Man9GlcNAc2Asn and a synthetic nonamannoside. We find that mannose spacing and valency dictate whether glycopeptides engage GRFT in a face-to-face or an intermolecular binding mode. Surprisingly, although face-to-face interactions are of higher affinity, intermolecular interactions are longer lived. These findings yield key insights into mechanisms involved in glycan-mediated viral inhibition. [ABSTRACT FROM AUTHOR]

Predicting the polymorphic stability of nanocrystals entails taking into account the thermodynamic effects from solid-vapor interfaces. With recent advances in microcalorimetry, it is finally possible to obtain reliable surface energy data which allow building of predictive diagrams, such as the usual phase diagrams for bulk crystals, for nanocrystals. Yttria doped zirconia (YZ) is currently utilized in a variety of applications; making it one of the most studied oxide systems to date. However, the polymorphism of nanocrystalline YZ (nYZ) is much less understood as compared to its bulk counterpart, and the stability conditions of cubic, tetragonal, monoclinic, and amorphous polymorphs at the nanoscale is so far only empirically defined. In this work, we present a new predictive nanoscale phase diagram for nYZ using unprecedented data on surface energies and bulk enthalpies acquired by microcalorimetry. The phase diagram shows the stable zirconia polymorph as a function of the composition and size. This is a useful tool and an important and novel advancement to relatively untouched bulk phase diagrams, which holds the key for reliable materials' design. [ABSTRACT FROM AUTHOR]

Fructose-1-phosphate (F1P) is the preferred effector of the catabolite repressor/activator (Cra) protein of the soil bacterium Pseudomonas putida but its ability to bind other metabolic intermediates in vivo is unclear. The Cra protein of this microorganism (Cra PP ) was submitted to mobility shift assays with target DNA sequences (the P fruB promoter) and candidate effectors fructose-1,6-bisphosphate (FBP), glucose 6-phosphate (G6P), and fructose-6-phosphate (F6P). 1 mM F1P was sufficient to release most of the Cra protein from its operators but more than 10 mM of FBP or G6P was required to free the same complex. However, isothermal titration microcalorimetry failed to expose any specific interaction between Cra PP and FBP or G6P. To solve this paradox, transcriptional activity of a P fruB -lacZ fusion was measured in wild-type and Δ fruB cells growing on substrates that change the intracellular concentrations of F1P and FBP. The data indicated that P fruB activity was stimulated by fructose but not by glucose or succinate. This suggested that Cra PP represses expression in vivo of the cognate fruBKA operon in a fashion dependent just on F1P, ruling out any other physiological effector. Molecular docking and dynamic simulations of the Cra-agonist interaction indicated that both metabolites can bind the repressor, but the breach in the relative affinity of Cra PP for F1P vs FBP is three orders of magnitude larger than the equivalent distance in the Escherichia coli protein. This assigns the Cra protein of P. putida the sole role of transducing the presence of fructose in the medium into a variety of direct and indirect physiological responses. [ABSTRACT FROM AUTHOR]

The interactions of Ca2+ and Mg2+ with [UO2(CO3)3]4− were studied by calcium ion selective electrode potentiometry and spectrophotometry. The stability constants of ternary Ca-UO2-CO3 and Mg-UO2-CO3 complexes were determined with calcium ion selective electrode potentiometry and optical absorption spectrophotometry, respectively. The enthalpies of complexation for two successive complexes, [CaUO2(CO3)3]2− and [Ca2UO2(CO3)3](aq), were determined for the first time by microcalorimetry. The data help to revise the speciation of uranium(VI) species under seawater conditions. In contrast to the previously accepted assumption that the highly negatively charged [UO2(CO3)3]4− is the dominant species, the revised speciation indicates that the dominant aqueous uranium(VI) species under seawater conditions is the neutral [Ca2UO2(CO3)3](aq). The results have a significant impact on the strategies for developing efficient sorption processes to extract uranium from seawater. [ABSTRACT FROM AUTHOR]

Recently studies indicate that the microcalorimetry is a suitable measurement for metabolic activities of organisms by recording the rate of heat outputs. In this work, we investigated the growth thermogenic curves of Escherichia coli (E. coli) affected by three kinds of Glycyrrhiza extracts by microcalorimetry. The power-time and exponential phase power-time curves of the E. coli growth at various concentrations of extracts were generated. The kinetic parameters such as the growth rate constants (C), maximum power outputs (Pm), peak times (Tm), and inhibition ratios were calculated and the relationships between Pm or Tm and C were established. Also, the clear correlations among the antimicrobial effects, Pm and C were obtained. The results revealed the Glycyrrhiza extracts had inhibitory activities towards E. coli while the Glycyrrhiza polysaccharides showed the most potent effects. [ABSTRACT FROM AUTHOR]

The adsorption of cationic polyelectrolytes (PEs) onto anionic silicone emulsion droplets, suspended in a sodium chloride solution is studied via electrophoretic mobility measurements and isothermal titration calorimetry. These model systems are studied to better understand the interactions governing PE adsorption-induced emulsion flocculation, which is relevant to many industrial applications. Electrophoretic mobility measurements provide critical information for rationalizing the effect of the PE charge density on the loss of stability of silicone emulsions. The interaction strength is calculated from a Langmuir adsorption isotherm determined by a ζ-potential titration measurement. Microcalorimetry measurements independently validate the adsorption free energy. Emulsion flocculation and coacervation are observed in the visual phase behavior as well as the ζ-potential titration measurements. The effect of PE charge density shows that PE-surfactant coacervation is the driving force in these PE-emulsion systems. [ABSTRACT FROM AUTHOR]

TiO2-, Al2O3-, and ZrO2-supported CeO2 catalysts with different Ce loadings were prepared by wet impregnation of the carriers with an acidified solution of cerium ammonium nitrate. The calcined catalysts were characterized by bulk and surface-sensitive techniques, which included microcalorimetry, and evaluated in the three-phase hydrogenation of alkynes under continuous-flow conditions at variable temperature (293-413 K) and pressure (1-90 bar). A number of acetylenic compounds, which contain terminal or internal triple bonds, conjugated unsaturations, and additional functionalities, were systematically assessed. The results revealed the full stereo- and chemoselective character of the ceria catalysts, which outperform the well-known Lindlar catalyst, and open promising perspectives for the revolutionary use of a cost-effective oxide for the production of olefinic compounds in the vitamin and fine chemical industries. [ABSTRACT FROM AUTHOR]

This study demonstrates gel-to-fluid transition temperatures of polydiacetylene bilayer vesicles could play important roles in their colorimetric transition temperatures. We prepared five types of polydiaceylene vesicles with 10,12-pentacosadiynoic acid (PCDA) and cholesterol (0-40 mol % of total content). From temperaturedependent observations of the optical signals (colors and UV-vis spectra), the blue-to-red colorimetric transition temperatures of polydiacetylene vesicles were decreased with the cholesterol contents. A further study with microcalorimetry and dynamic light scattering revealed that the polydiacetylene vesicles first underwent gel-to-fluid transitions, which were followed by event(s) responsible for the colorimetric transitions. Energies required for each event were quantified from analysis of the peaks in the microcalorimetry thermograms. The inclusion of cholesterol in the vesicles decreased both the gel-to-fluid and the colorimetric transition temperatures, suggesting that the colorimetric transition of the polydiacetylene vesicles was mediated by the former event although the event was not the direct reason for the color change. [ABSTRACT FROM AUTHOR]

Thermoplastic polyurethane (TPU) - calcium carbonate interactions were studied using flow micro-calorimetry (FMC) and diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS). FMC enabled the determination of adsorption and desorption energies; in this study a model compound approach was used to acquire insight in to the effect of calcium carbonate type and presence of stearate coating on polymer - filler interactions. It was anticipated that this data will assist in the understanding of differing responses obtained from parallel plate rheometry and viscoelastic measurements of the filled polyurethanes. Three calcium carbonates (coated and uncoated precipitated calcium carbonate, and natural ultramicronized uncoated calcium carbonate) were used. A stronger TPU-filler interaction was shown in the uncoated precipitated calcium carbonate due to the fact that more of the surface was available for interaction. [ABSTRACT FROM AUTHOR]

Background: The mechanism of action of adjuvant antibiotic therapy in the treatment of peri-implantitis is not well understood. The aim of this study is to investigate antibiotic susceptibility of an in vitro biofilm by isothermal microcalorimetry (IMC). Methods: Titanium disks containing a 72-hour three-species biofilm (Streptococcus sanguinis DSM20068, Fusobacterium nucleatum ATCC10953, and Porphyromonas gingivalis DSM20709) were placed in a series of IMC ampoules with nutrient agar supplemented with increasing concentrations of amoxicillin, metronidazole, or their combination and incubated anaerobically for 10 days. Lag time and maximum growth rate were determined from continuous heat-flow recordings of metabolic activity. To validate the IMC biofilm results, adherent S. sanguinis and P. gingiualis were incubated anaerobically in medium supplemented with antibiotics at 37°C for 24 hours, and their vitality was determined by live/dead staining, conventional culturing, and IMC. Results: In all biofilm samples incubated with antibiotics, a prolonged lag phase was observed compared with controls (P <0.05). Maximum growth rate was significantly lower for samples treated with either amoxicillin or metronidazole compared with controls (P <0.05). Combining the antibiotics did not improve this effect. Concentrations exceeding 10 times the minimum inhibitory concentration completely inhibited the growth of adherent S. sanguinis and P. gingivalis, whereas lower concentrations resulted in only a delay in the lag phase. A poor correlation was observed between live/dead staining and conventional culturing. Conclusions: IMC gives new evidence about antibiotic effects on oral biofilms and is more informative than conventional culture and live/dead assays. The combination of antibiotics was found to be more efficient than metronidazole alone; however, only minor differences in growth inhibition were detected compared with amoxicillin alone. [ABSTRACT FROM AUTHOR]

A microcalorimetric study on the inclusion of monovalent and divalent metal cations by p-sulfonatocalix[4]arene was performed. The thermodynamic parameters for the complexation of alkali metal cations and Ag+ were obtained for the first time at neutral pH. The Na+ cation is routinely present as counterion of the calixarene in neutral aqueous solution, and this must be taken into account in the determination of the thermodynamic parameters for the complexation of Na+ and the other cations by considering a sequential or a competitive binding scheme. The Δ H° and Δ S° values show that the inclusion process is entropically driven, although an influence of the temperature on the complexation reaction indicates that the enthalpic term is also an important contributor. The results also reveal that enthalpy/entropy compensation balances the gain in one contribution against a corresponding loss in the other. The obtained thermodynamic data are in contrast to the results from previous microcalorimetric studies, which showed binding constants that were orders of magnitude smaller and complexations, which were in part enthalpically driven but which neglected the influence of the alkali metal counterions. [ABSTRACT FROM AUTHOR]

The complexation of NpO22+ and PuO22+ with dipicolinic acid (DPA) has been investigated in 0.1 M NaClO4 by spectrophotometry, microcalorimetry, and single crystal diffractometry. Formation of 1:1 and 1:2 (metal/ligand molar ratio) complexes of DPA with NpO22+ and PuO22+ were identified and the thermodynamic parameters were determined and compared with those of UO22+. All three hexavalent actinyl cations form strong 1:1 DPA complexes with slightly decreasing but comparable stability constants from UO22+ to PuO22+, whereas the stability constants of the 1:2 complexes (log β2) decrease substantially along the series (16.3 for UO2L22−, 15.17 for NpO2L22−, and 14.17 for PuO2L22− at 25 °C). The enthalpies of complexation for the 1:2 complexes become less exothermic from UO2L22− (−28.9 kJ mol−1), through NpO2L22− (−27.2 kJ mol−1), and to PuO2L22− (−22.7 kJ mol−1). The trends in the thermodynamic parameters are discussed in terms of the effective charge of the cations and the steric constraints in the structures of the complexes. In addition, the features of the absorption spectra, including the wavelength and intensity of the absorption bands, are related to the perturbation of the ligand field and the symmetry of the actinyl complexes. [ABSTRACT FROM AUTHOR]

The complexation of NpO22+ and PuO22+ with dipicolinic acid (DPA) has been investigated in 0.1 M NaClO4 by spectrophotometry, microcalorimetry, and single crystal diffractometry. Formation of 1:1 and 1:2 (metal/ligand molar ratio) complexes of DPA with NpO22+ and PuO22+ were identified and the thermodynamic parameters were determined and compared with those of UO22+. All three hexavalent actinyl cations form strong 1:1 DPA complexes with slightly decreasing but comparable stability constants from UO22+ to PuO22+, whereas the stability constants of the 1:2 complexes (log β2) decrease substantially along the series (16.3 for UO2L22−, 15.17 for NpO2L22−, and 14.17 for PuO2L22− at 25 °C). The enthalpies of complexation for the 1:2 complexes become less exothermic from UO2L22− (−28.9 kJ mol−1), through NpO2L22− (−27.2 kJ mol−1), and to PuO2L22− (−22.7 kJ mol−1). The trends in the thermodynamic parameters are discussed in terms of the effective charge of the cations and the steric constraints in the structures of the complexes. In addition, the features of the absorption spectra, including the wavelength and intensity of the absorption bands, are related to the perturbation of the ligand field and the symmetry of the actinyl complexes. [ABSTRACT FROM AUTHOR]

Phosphorylation adjacent to nuclear localization signals (NLSs) is involved in the regulation of nucleocytoplasmic transport. The nuclear isoform of human dUTPase, an enzyme that is essential for genomic integrity, has been shown to be phosphorylated on a serine residue (Serll) in the vicinity of its nuclear localization signal; however, the effect of this phosphorylation is not yet known. To investigate this issue, an integrated set of structural, molecular and cell biological methods were employed. It is shown that NLS-adjacent phosphorylation of dUTPase occurs during the M phase of the cell cycle. Comparison of the cellular distribution of wild-type dUTPase with those of hyperphosphorylation- and hypophosphorylation- mimicking mutants suggests that phosphorylation at Serl 1 leads to the exclusion of dUTPase from the nucleus. Isothermal titration microcalorimetry and additional independent biophysical techniques show that the interaction between dUTPase and importin-a, the karyopherin molecule responsible for "classical' NLS binding, is weakened significantly in the case of the SHE hyperphosphorylation-mimicking mutant. The structures of the importin-a-wild-type and the importin-a-hyperphosphorylation-mimicking dUTPase NLS complexes provide structural insights into the molecular details of this regulation. The data indicate that the posttranslational modification of dUTPase during the cell cycle may modulate the nuclear availability of this enzyme. [ABSTRACT FROM AUTHOR]

Proper and rapid diagnosis of orthopedic device-related infection is important for successful treatment. Sonication has been shown to improve the diagnostic performance. We hypothesized that the combination of sonication with a novel method called microcalorimetry will further improve and accelerate the diagnosis of implant infection. We prospectively included 39 consecutive patients (mean age 59 years, 62% males) at our institution from whom 29 orthopedic prostheses and 10 osteosynthesis material were explanted. The explanted device was sonicated. The resulting sonication fluid was analyzed using microcalorimetry. Using standardized criteria to define orthopedic device-related infection, 12 cases (31%) were defined as infected. In all, positive periprosthetic tissue cultures were found. The sensitivity and specificity of microcalorimetry of sonication fluid were 100% and 97%, respectively. Mean time to detection, defined as time to reach a rising heat flow signal of 20 µW measured after equilibiration needed to get accurate measurement, was 10.9 h. In summary, microcalorimetry of sonication fluid is a reliable and a fast method in detecting the presence of microorganisms in orthopedic device-related infection. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1700-1703, 2013 [ABSTRACT FROM AUTHOR]

The grafting of HDPE and LLDPE with itaconic acid (AIt) was made by reactive extrusion using the peroxide 2,5-dimethyl-2,5-di(tert-butyli) peroxy hexane (trigonox 101) as initiator. The graft efficiency was evaluated using FTIR to identify bands of carbonyl groups in the polymer. It is influence on the addition of itaconic acid in the structure of the polymer chain was evaluated using CRYSTAF and microcalorimetry, where it was show that the incorporated acid causes a narrow crystallization profile and the decrease of the percentage of the soluble fraction at 30 °C. The polymers were fractionated by molecular weight and chemical composition to check the distribution of the AIt incorporation, the percentage of AIt was quantified in each fraction by FTIR, and it was show that the incorporation of AIt occurred homogeneously in all the chains. [ABSTRACT FROM AUTHOR]

Uniform CdMoO4 nanooctahedra with tunable sizes have been synthesised via a facile and mild microemulsion method at room temperature. The reaction between CdMoO4 nanooctahedra and dilute hydrochloric acid was in situ monitored using microcalorimetry at 298.15 K, and microcalorimetric heat flow curves from this reaction process were obtained. Combined with an inductively coupled plasma optical emission spectrometer technique, the size effect of CdMoO4 nanooctahedra on standard molar reaction enthalpy (ΔrHmƟ) was studied. The results indicate that the value of ΔrHmƟ decreased with decreased particle size. [ABSTRACT FROM AUTHOR]

The binding of representative alkali, alkaline earth, transition and heavy metal cations by 2-pyridylmethoxy derivatives (1b, in cone and partial cone conformations) of p-tert-butylhexahomotrioxacalix[3]arene was studied. Binding was assessed by extraction studies of the metal picrates from water into dichloromethane and by stability constant measurements in acetonitrile and methanol, using spectrophotometric and potentiometric techniques. Microcalorimetric studies of some selected complexes in acetonitrile were performed, as well as proton NMR titrations. Computational methods (density functional theory calculations) were also employed to complement the NMR data. The results are compared with those obtained with the dihomooxacalix[4]arene 2b and the calix[4]arene 3b derivative analogues. Partial cone-1b is the best extractant for transition and heavy metal cations. Both conformers of 1b exhibit very high stability constants for soft and intermediate cations Pb2+, Cd2+, Hg2+, Zn2+ and Ni2+, with cone-1b the strongest binder (ML, log β ≥ 7) and partial cone-1b the most selective. Both derivatives show a slight preference for Na+. Besides the formation of ML complexes, ML2 and M2L species were also observed. The former complexes were, in general, formed with the transition and heavy metal cations, whereas the latter were obtained with Ag+ and Hg2+ and partial cone-1b. In most cases, these species were corroborated by the proton NMR and density functional theory studies. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]