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Swapan K Roy, Vincent T K Sauer, Jocelyn N Westwood-Bachman, Anandram Venkatasubramanian, Wayne K Hiebert
Mechanical resonances are used in a wide variety of devices, from smartphone accelerometers to computer clocks and from wireless filters to atomic force microscopes. Frequency stability, a critical performance metric, is generally assumed to be tantamount to resonance quality factor (the inverse of the linewidth and of the damping). We show that the frequency stability of resonant nanomechanical sensors can be improved by lowering the quality factor. At high bandwidths, quality-factor reduction is completely mitigated by increases in signal-to-noise ratio...
June 15, 2018: Science
Roger Krenger, Thomas Lehnert, Martin A M Gijs
Basal heat production is a key phenotype for assessing the metabolic activity of small living organisms. Here, we present a new nanocalorimetric system, based on thin film thermopile sensors combined with microfluidic chips for measuring metabolic heat signals generated by Caenorhabditis elegans larval populations (60 to 220 organisms). In addition to versatile on-chip fluidic manipulation, our microfluidic approach allows confining worm populations close to the sensor surface, thus increasing the sensitivity of the assays...
May 17, 2018: Lab on a Chip
M S Beasley, M Tylinski, Y Z Chua, C Schick, M D Ediger
In situ AC nanocalorimetry was used to characterize vapor-deposited glasses of three phosphates with increasing lengths of alkyl side chains: trimethyl phosphate, triethyl phosphate, and tributyl phosphate. The as-deposited glasses were assessed in terms of their reversing heat capacity, onset temperature, and isothermal transformation time. Glasses with a range of kinetic stabilities were prepared, including kinetically stable glasses, as indicated by high onset temperatures and long transformation times. Trimethyl phosphate forms kinetically stable glasses, similar to many other organic molecules, while triethyl phosphate and tributyl phosphate do not...
May 7, 2018: Journal of Chemical Physics
Alberto Robador, Douglas E LaRowe, Steven E Finkel, Jan P Amend, Kenneth H Nealson
Calorimetric measurements of the change in heat due to microbial metabolic activity convey information about the kinetics, as well as the thermodynamics, of all chemical reactions taking place in a cell. Calorimetric measurements of heat production made on bacterial cultures have recorded the energy yields of all co-occurring microbial metabolic reactions, but this is a complex, composite signal that is difficult to interpret. Here we show that nanocalorimetry can be used in combination with enumeration of viable cell counts, oxygen consumption rates, cellular protein content, and thermodynamic calculations to assess catabolic rates of an isolate of Shewanella oneidensis MR-1 and infer what fraction of the chemical energy is assimilated by the culture into biomass and what fraction is dissipated in the form of heat under different limiting conditions...
2018: Frontiers in Microbiology
K Willa, Z Diao, D Campanini, U Welp, R Divan, M Hudl, Z Islam, W-K Kwok, A Rydh
Recent advances in electronics and nanofabrication have enabled membrane-based nanocalorimetry for measurements of the specific heat of microgram-sized samples. We have integrated a nanocalorimeter platform into a 4.5 T split-pair vertical-field magnet to allow for the simultaneous measurement of the specific heat and x-ray scattering in magnetic fields and at temperatures as low as 4 K. This multi-modal approach empowers researchers to directly correlate scattering experiments with insights from thermodynamic properties including structural, electronic, orbital, and magnetic phase transitions...
December 2017: Review of Scientific Instruments
Feng Yi, Ana Stevanovic, William A Osborn, A Kolmakov, David A LaVan
We have developed a versatile nanocalorimeter sensor which allows imaging and electrical measurements of samples under different gaseous environments using the scanning electron microscope (SEM) and can simultaneously measure the sample temperature and associated heat of reaction. This new sensor consists of four independent heating/sensing elements for nanocalorimetry and eight electrodes for electrical measurements, all mounted on a 50 nm thick, 250 μm × 250 μm suspended silicon nitride membrane. This membrane is highly electron transparent and mechanically robust enabling in situ SEM observation under realistic temperatures, environmental conditions and pressures up to one atmosphere...
November 2017: Materials Horizons
Bingge Zhao, Bin Yang, Alexander S Abyzov, Jürn W P Schmelzer, Javier Rodriguez-Viejo, Qijie Zhai, Christoph Schick, Yulai Gao
In this paper, the amorphous Ce68Al10Cu20Co2 (at. %) alloy was in situ prepared by nanocalorimetry. The high cooling and heating rates accessible with this technique facilitate the suppression of crystallization on cooling and the identification of homogeneous nucleation. Different from the generally accepted notion that metallic glasses form just by avoiding crystallization, the role of nucleation and growth in the crystallization behavior of amorphous alloys is specified, allowing an access to the ideal metallic glass free of nuclei...
November 7, 2017: Nano Letters
Jozef Lengyel, Jakub Med, Petr Slavíček, Martin K Beyer
The reaction of HNO3 with hydrated electrons (H2O)n(-) (n = 35-65) in the gas phase was studied using Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry and ab initio molecular dynamics simulations. Kinetic analysis of the experimental data shows that OH(-)(H2O)m is formed primarily via a reaction of the hydrated electron with HNO3 inside the cluster, while proton transfer is not observed and NO3(-)(H2O)m is just a secondary product. The reaction enthalpy was determined using nanocalorimetry, revealing a quite exothermic charge transfer with -241 ± 69 kJ mol(-1)...
September 14, 2017: Journal of Chemical Physics
Natália Moreira Nunes, Ana Flávia Coelho Pacheco, Álvaro Javier Patiño Agudelo, Luis Henrique Mendes da Silva, Maximiliano Soares Pinto, Maria do Carmo Hespanhol, Ana Clarissa Dos Santos Pires
Cinnamic acid (CA) and methyl cinnamate (MC) have attracted interest of researchers because of their broad therapeutic functions. Here, we investigated the interaction of CA and MC with bovine serum albumin (BSA) at pH 3.5, 5.0, and 7.4 using fluorescence spectroscopy, differential scanning nanocalorimetry, and measurements of interfacial tension, size, and zeta potential. BSA formed a complex with the ligands with stoichiometry of approximately 1.0. At pH 7.4, CA-BSA complex formation was entropically driven...
December 15, 2017: Food Chemistry
Y Z Chua, A R Young-Gonzales, R Richert, M D Ediger, C Schick
Physical vapor deposition has been used to prepare glasses of ethanol. Upon heating, the glasses transformed into the supercooled liquid phase and then crystallized into the plastic crystal phase. The dynamic glass transition of the supercooled liquid is successfully measured by AC nanocalorimetry, and preliminary results for the plastic crystal are obtained. The frequency dependences of these dynamic glass transitions observed by AC nanocalorimetry are in disagreement with conclusions from previously published dielectric spectra of ethanol...
July 7, 2017: Journal of Chemical Physics
Joan Ràfols-Ribé, Marta Gonzalez-Silveira, Cristian Rodríguez-Tinoco, Javier Rodríguez-Viejo
Physical vapour deposition (PVD) has settled in as an alternative method to prepare glasses with significantly enhanced properties, providing new insights into the understanding of glass transition. One of the striking properties of some PVD glasses is their transformation into liquid via a heterogeneous mechanism that initiates at surfaces/interfaces. Here, we use membrane-based fast-scanning nanocalorimetry (104 K s-1 ) to analyse the variables that govern the transformation mechanism of vapour-deposited toluene glasses with different stabilities...
May 10, 2017: Physical Chemistry Chemical Physics: PCCP
M Tylinski, Y Z Chua, M S Beasley, C Schick, M D Ediger
In situ AC nanocalorimetry was used to characterize vapor-deposited glasses of six mono- and di-alcohol molecules. Benzyl alcohol glasses with high kinetic stability and decreased heat capacity were prepared. When annealed above the glass transition temperature Tg, transformation of these glasses into the supercooled liquid took 10(3.4) times longer than the supercooled liquid relaxation time (τα). This kinetic stability is similar to other highly stable organic glasses prepared by vapor deposition and is the first clear demonstration of an alcohol forming a stable glass...
November 7, 2016: Journal of Chemical Physics
Jozef Lengyel, Christian van der Linde, Michal Fárník, Martin K Beyer
The reaction of dichlorodifluoromethane (CF2Cl2) with hydrated electrons (H2O)n(-) (n = 30-86) in the gas phase was studied using Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. The hydrated electron reacts with CF2Cl2, forming (H2O)mCl(-) with a rate constant of (8.6 ± 2.2) × 10(-10) cm(3) s(-1), corresponding to an efficiency of 57 ± 15%. The reaction enthalpy was determined using nanocalorimetry, revealing a strongly exothermic reaction with ΔHr(CF2Cl2, 298 K) = -208 ± 41 kJ mol(-1)...
September 14, 2016: Physical Chemistry Chemical Physics: PCCP
Amou Akhgarnusch, Wai Kit Tang, Han Zhang, Chi-Kit Siu, Martin K Beyer
The recombination reactions of gas-phase hydrated electrons (H2O)n˙(-) with CO2 and O2, as well as the charge exchange reaction of CO2˙(-)(H2O)n with O2, were studied by Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry in the temperature range T = 80-300 K. Comparison of the rate constants with collision models shows that CO2 reacts with 50% collision efficiency, while O2 reacts considerably slower. Nanocalorimetry yields internally consistent results for the three reactions. Converted to room temperature condensed phase, this yields hydration enthalpies of CO2˙(-) and O2˙(-), ΔHhyd(CO2˙(-)) = -334 ± 44 kJ mol(-1) and ΔHhyd(O2˙(-)) = -404 ± 28 kJ mol(-1)...
September 14, 2016: Physical Chemistry Chemical Physics: PCCP
Y Z Chua, M Tylinski, S Tatsumi, M D Ediger, C Schick
Physical vapor deposition (PVD) has been used to prepare organic glasses with very high kinetic stability and it has been suggested that molecular anisotropy is a prerequisite for stable glass formation. Here we use PVD to prepare glasses of tetrachloromethane, a simple organic molecule with a nearly isotropic molecular structure. In situ AC nanocalorimetry was used to characterize the vapor-deposited glasses. Glasses of high kinetic stability were produced by deposition near 0.8 Tg. The isothermal transformation of the vapor-deposited glasses into the supercooled liquid state gave further evidence that tetrachloromethane forms glasses with high kinetic stability, with the transformation time exceeding the structural relaxation time of the supercooled liquid by a factor of 10(3)...
June 28, 2016: Journal of Chemical Physics
Michael I Recht, Vicki Nienaber, Francisco E Torres
Isothermal titration calorimetry (ITC) provides a sensitive and accurate means by which to study the thermodynamics of binding reactions. In addition, it enables label-free measurement of enzymatic reactions. The advent of extremely sensitive microcalorimeters have made it increasingly valuable as a tool for hit validation and characterization, but its use in primary screening is hampered by requiring large quantities of reagents and long measurement times. Nanocalorimeters can overcome these limitations of conventional ITC, particularly for screening libraries of 500-1000 compounds such as those encountered in fragment-based lead discovery...
2016: Methods in Enzymology
Cristian Rodríguez-Tinoco, Marta Gonzalez-Silveira, Joan Ràfols-Ribé, Aitor F Lopeandía, Javier Rodríguez-Viejo
While ordinary glasses transform into supercooled liquid via a homogeneous bulk mechanism, thin film glasses of higher stability transform heterogeneously by a front propagating from the surface and/or the interfaces. In this work, we use quasi-adiabatic fast scanning nanocalorimetry to determine the heat capacity of thin glassy layers of indomethacin vapor-deposited in a broad temperature range of 110 K below the glass transition temperature. Their variation in fictive temperature amounts to 40 K. We show that a propagating front is the initial transformation mechanism in all cases...
December 14, 2015: Physical Chemistry Chemical Physics: PCCP
Dongwoo Lee, Gi-dong Sim, Kejie Zhao, Joost J Vlassak
Reactive nanolaminates afford a promising route for the low-temperature synthesis of zirconium diboride, an ultrahigh-temperature ceramic with metallic properties. Although the addition of carbon is known to facilitate sintering of ZrB2, its effect on the kinetics of the formation reaction has not been elucidated. We have employed a combined approach of nanocalorimetry and first-principles theoretical studies to investigate the kinetic role of carbon in the synthesis of ZrB2 using B4C/Zr reactive nanolaminates...
December 9, 2015: Nano Letters
Feng Yi, Jeffery B DeLisio, Michael R Zachariah, David A LaVan
We report on measurements integrating a nanocalorimeter sensor into a time-of-flight mass spectrometer (TOFMS) for simultaneous thermal and speciation measurements at high heating rates. The nanocalorimeter sensor was incorporated into the extraction region of the TOFMS system to provide sample heating and thermal information essentially simultaneously with the evolved species identification. This approach can be used to measure chemical reactions and evolved species for a variety of materials. Furthermore, since the calorimetry is conducted within the same proximal volume as ionization and ion extraction, evolved species detected are in a collision-free environment, and thus, the possibility exists to interrogate intermediate and radical species...
October 6, 2015: Analytical Chemistry
Amou Akhgarnusch, Robert F Höckendorf, Martin K Beyer
The reaction of sulfur hexafluoride with gas-phase hydrated electrons (H2O)n(-), n ≈ 60-130, is investigated at temperatures T = 140-300 K by Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. SF6 reacts with a temperature-independent rate of 3.0 ± 1.0 × 10(-10) cm(3) s(-1) via exclusive formation of the hydrated F(-) anion and the SF5(•) radical, which evaporates from the cluster. Nanocalorimetry yields a reaction enthalpy of ΔHR,298K = 234 ± 24 kJ mol(-1). Combined with literature thermochemical data from bulk aqueous solution, these result in an F5S-F bond dissociation enthalpy of ΔH298K = 455 ± 24 kJ mol(-1), in excellent agreement with all high-level quantum chemical calculations in the literature...
October 1, 2015: Journal of Physical Chemistry. A
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