• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2460-2464
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• 2014

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.

• Journal of Energy Engineering
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• v.23 no.1
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• pp.1-6
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• 2014

We have surveyed on microcalorimetry which we can treat with energy dispersive spectrometer(EDS) as wavelength dispersive spectrometer(WDS), to be developed in order to make higher energy resolution as to detect X-ray peak as high as wavelength dispersive spectrometer(WDS). When we take into consideration about energy resolution, Wavelength dispersive spectrometer is 2~20eV and energy dispersive spectrometer is 140~180eV.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1809-1816
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• 2014

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 temperature-dependent 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.

• BMB Reports
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• v.35 no.3
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• pp.302-305
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• 2002

Kinetic and thermodynamic studies have been made on the effect of the inosine product on the activity of adenosine deaminase in a 50 mM sodium phosphate buffer, pH 7.5, at $27^{\circ}C$ using UV spectrophotometry and isothermal titration calorimetry (ITC). A competitive inhibition was observed for inosine as a product of the enzymatic reaction. A graphical-fitting method was used for determination of the binding constant and enthalpy of inhibitor binding by using isothermal titration microcalorimetry data. The dissociation-binding constant is equal to $140\;{\mu}M$ by the microcalorimetry method, which agrees well with the value of $143\;{\mu}M$ for the inhibition constant that was obtained from the spectroscopy method.

• Bulletin of the Korean Chemical Society
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• v.24 no.5
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• pp.547-551
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• 2003

In the present work, the interaction of three water soluble porphyrins, tetra(p-trimethyle) ammonium phenyl porphyrin iodide (TAPP) as a cationic porphyrin, tetra sodium meso-tetrakis (p-sulphonato phenyle) porphyrin (TSPP) as an anionic porphyrin and manganese tetrakis (p-sulphonato phenyl) porphinato acetate (MnTSPP) as a metal porphyrin, with histone H₂B have been studied by isothermal titration microcalorimetry at 8 mM phosphate buffer, pH 6.8 and 27 °C. The values of binding constant, entropy, enthalpy and Gibbs free energy changes for binding of the first MnTSPP, and first and second TSPP and TAPP molecules were estimated from microcalorimetric data analysis. The results represent that the process is both entropy and enthalpy driven and histone induces self-aggregation of the porphyrins. The results indicate that both columbic and hydrophobic interactions act as self-aggregation driving forces for the formation of aggregates around histone.

• 한국연소학회:학술대회논문집
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• 2001.11a
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• pp.90-96
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• 2001

Catalytic ignition of $H_2/O_2/CO_2$ mixtures over platinum catalyst is experimentally investigated by using microcalorimetry. For comparison, $N_2$ and Ar is also used as diluent gas. The gas mixture flows toward platinum foil heated by electric current at atmosphere pressure and ambient temperature. The ignition temperature range 350-445K according to the fuel ratio, dilution ratio and diluent gas. It increases as the fuel ratio and dilution ratio increase. $H_2/O_2$ mixture with $CO_2$ ignites at higher temperature than with other diluents by 30-50K. Several experimental evidences show the inhibition effects of $CO_2$ in $H_2-O_2$ heterogeneous reaction is considerable

• Bulletin of the Korean Chemical Society
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• v.26 no.7
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• pp.1051-1056
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• 2005

The interaction of bovine carbonic anhydrase II with copper ions was studied by isothermal titration microcalorimetry, circular dichroism, UV spectrophotometry and temperature scanning spectrophotometry methods at 27 ${^{\circ}C}$ in Tris buffer solution at pH = 7.5. It was indicated that there are three non-identical different binding sites on carbonic anhydrase for $Cu^{2+}$. The binding of copper ions is exothermic and can induce some minor changes in the secondary and tertiary structure of the enzyme, which does not unfold it, but can result in a decrease in both activity and stability of the enzyme.

• Macromolecular Research
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• v.15 no.7
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• pp.623-632
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• 2007

Thermosensitive nanoparticles were prepared via the self-assembly of two different $poly({\varepsilon}-caprolactone)$-based block copolymers of poly(N-isopropylacrylamide)-b-$poly({\varepsilon}-caprolactone)$ (PNPCL) and poly(ethylene glycol)-b-$poly({\varepsilon}-caprolactone)$ (PEGCL). The self-aggregation and thermosensitive behaviors of the mixed nanoparticles were investigated using $^1H-NMR$, turbidimetry, differential scanning microcalorimetry (micro-DSC), dynamic light scattering (DLS), and fluorescence spectroscopy. The copolymer mixtures (mixed nanoparticles, M1-M5, with different PNPCL content) formed nano-sized self-aggregates in an aqueous environment via the intra- and/or intermolecular association of hydrophobic PCL chains. The microscopic investigation of the mixed nanoparticles showed that the critical aggregation concentration (cac), the partition equilibrium constants $(K_v)$ of pyrene, and the aggregation number of PCL chains per one hydrophobic microdomain varied in accordance with the compositions of the mixed nanoparticles. Furthermore, the PNPCL harboring mixed nanoparticles evidenced phase transition behavior, originated by coil to the globule transition of PNiPAAm block upon heating, thereby resulting in the turbidity change, endothermic heat exchange, and particle size reduction upon heating. The drug release tests showed that the formation of the thermosensitive hydrogel layer enhanced the sustained drug release patterns by functioning as an additional diffusion barrier.

• Biomaterials and Biomechanics in Bioengineering
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• v.2 no.1
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• pp.15-22
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• 2015

Poly(ethylene glycol) end-capped with pentafluorophenyl group(s) in ABA (FP-PEG-FP) and AB (mPEG-FP) types were prepared. Even though they were similar in composition, the lower critical solution temperature (LCST) of FP-PEG-FP was observed at $23^{\circ}C$, whereas that of mPEG-FP was observed at $65^{\circ}C$. To understand the large difference in solution behaviour of the two polymers, UV-VIS spectroscopy, microcalorimetry, 1H-NMR spectroscopy, and dynamic light scattering were used. FP-PEG-FP has two hydrophobic pentafluorophenyl groups at the ends of hydrophilic PEG (1000 Daltons), whereas mPEG-PF has a highly dynamic PEG (550 Daltons) block that are anchored to a hydrophobic pentafluorophenyl group. PF-PEG-PF not only has a smaller conformational degree of freedom than mPEG-PF but also can form extensive intermolecular aggregates, therefore, PF-PEG-PF exhibits a significantly lower LCST than mPEG-PF. This paper suggests that topological control is very important in designing a temperature-sensitive polymer.

• Textile Coloration and Finishing
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• v.33 no.4
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• pp.230-237
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• 2021

The flame-retardant (FR) treatments of wool fibers using Hexafluorozirconate/titanate salts and tetrabromophthalic anhydride can cause skin irritation and gas toxicity due to Zr and Br compounds respectively. A water-soluble polyfunctional cyclophosphazene derivative, synthesized through substitution reaction of Hexachloro cyclophosphazene and N-[3-(Dimethylamino)propyl] metacrylamide, was applied as a durable flame-retardant for wool fabrics. Also, a crosslinked structure was introduced to improve washing durability of the FR-wool, up to 10 laundering cycles, using Acrylamide(AAm) and Triacryloylhexahydrotriazine (TAHT) as a comonomer and a crosslinker respectively. The mole ratios of the TAHT and AAm concentrations compared to the Dichloro tetrakis{N-[3-(Dimethylamino)propyl]methacrylamido} cyclcophosphazene (DCTDCP) were optimized to 1.33 and 7.5 respectively. In addition, the pyrolysis and combustion properties of the FR wool were assessed using LOI, TGA and microcalorimetry suggesting a solid-phase FR mechanism.