scholarly journals Hydration dependence of myoglobin dynamics studied with elastic neutron scattering, differential scanning calorimetry and broadband dielectric spectroscopy

2014 ◽  
Vol 185 ◽  
pp. 25-31 ◽  
Author(s):  
Margarita Fomina ◽  
Giorgio Schirò ◽  
Antonio Cupane
Keyword(s):  
Differential Scanning Calorimetry ◽  
Neutron Scattering ◽  
Dielectric Spectroscopy ◽  
Scanning Calorimetry ◽  
Elastic Neutron ◽  
Broadband Dielectric Spectroscopy ◽  
Elastic Neutron Scattering

Thermal behavior, structure, and dynamics of low-temperature water confined in mesoporous organosilica by differential scanning calorimetry, X-ray diffraction, and quasi-elastic neutron scattering

2012 ◽  
Vol 85 (1) ◽  
pp. 289-305 ◽  
Author(s):  
Mai Aso ◽  
Kanae Ito ◽  
Hiroaki Sugino ◽  
Koji Yoshida ◽  
Takeshi Yamada ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Water Molecule ◽  
Neutron Scattering ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Elastic Neutron ◽  
X Ray ◽  
Mesoporous Organosilica ◽  
Condensed Water ◽  
Elastic Neutron Scattering

Differential scanning calorimetry (DSC), X-ray diffraction (XRD), and quasi-elastic neutron scattering (QENS) measurements have been made at 200~330 K for capillary-condensed water confined in periodic mesoporous organosilica (PMO) materials with the phenyl groups embedded in silica matrix (Ph-PMO; pore diameter 30 Å). The DSC data showed that the capillary-condensed water in Ph-PMO freezes at 228 K. X-ray radial distribution functions (RDFs) showed that the tetrahedral-like hydrogen-bonded structure of water is distorted in Ph-PMO pores, compared with bulk water; however, with lowering temperature the tetrahedral moiety of water is gradually recovered in the pores. Below the freezing point, cubic ice Ic was formed in the Ph-PMO pores. The QENS data showed that the translational diffusion constant and the residence time and the rotational relaxation time of water molecule in Ph-PMO are comparable with those in bulk. The corresponding activation energies suggested that the more hydrophobic the nature of the wall is, the smaller the activation energy of diffusion and rotation of a water molecule; this implies that water molecules confined in the hydrophobic pores are present in the core of the pores, whereas those in the hydrophilic pores strongly interact with the silanol groups.

Molecular Dynamics and Kinetics of Isothermal Cold Crystallization in the Chiral Smectogenic 3F7HPhH6 Glassformer

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1487
Author(s):  
Aleksandra Deptuch ◽  
Małgorzata Jasiurkowska-Delaporte ◽  
Ewa Juszyńska-Gałązka ◽  
Anna Drzewicz ◽  
Wojciech Zając ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Optical Microscopy ◽  
Dielectric Spectroscopy ◽  
Cold Crystallization ◽  
Scanning Calorimetry ◽  
Broadband Dielectric Spectroscopy ◽  
Smectic C ◽  
Dimension Analysis ◽  
Fractal Dimension Analysis ◽  
Kinetics Of

An investigation of the glass transition of the antiferroelectric smectic C*A phase and cold crystallization of (S)-4’-(1-methylheptylcarbonyl)biphenyl-4-yl 4-[7-(2,2,3,3,4,4,4-heptafluoro- butoxy)heptyl-1-oxy]benzoate (denoted as 3F7HPhH6) by differential scanning calorimetry, polarizing optical microscopy and broadband dielectric spectroscopy is presented. The fragility index mf = 72, classifying 3F7HPhH6 as a glassformer with intermediate fragility, was obtained from the temperature dependence of the α-process relaxation time, measured upon cooling. Duplication of the α-process was observed exclusively upon heating, before the onset of cold crystallization, and is connected with the pre-transitional effect. The presence of two crystal phases likely influences the kinetics of cold crystallization; the idea stems from a comparison with previous results for the 3F7HPhF6 and 3F7HPhH7 compounds. Additionally, the presence of the smectic C*α; sub-phase in a narrow temperature range was proved based on the differential scanning calorimetry and broadband dielectric spectroscopy results, as well as the fractal dimension analysis of the textures obtained by polarizing optical microscopy.

scholarly journals Kinetics of Non-Isothermal and Isothermal Crystallization in a Liquid Crystal with Highly Ordered Smectic Phase as Reflected by Differential Scanning Calorimetry, Polarized Optical Microscopy and Broadband Dielectric Spectroscopy

Crystals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 205 ◽  
Author(s):  
Małgorzata Jasiurkowska-Delaporte ◽  
Tomasz Rozwadowski ◽  
Ewa Juszyńska-Gałązka
Keyword(s):  
Differential Scanning Calorimetry ◽  
Optical Microscopy ◽  
Dielectric Spectroscopy ◽  
Isothermal Crystallization ◽  
Glassy State ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Polarized Optical Microscopy ◽  
Broadband Dielectric Spectroscopy ◽  
Kinetics Of

The kinetics of the non-isothermal and isothermal crystallization of the crystalline smectic B phase (soft crystal B, SmBcr) in 4-n-butyloxybenzylidene-4′-n′-octylaniline (BBOA) was studied by a combination of differential scanning calorimetry (DSC), broadband dielectric spectroscopy (BDS) and polarized optical microscopy (POM). On cooling, part of the SmBcr phase undergoes conversion to a crystalline phase and the remainder forms a glassy state; after the glass softens, crystallization is completed during subsequent heating. By analyzing the area of the crystal growing in the texture of SmBcr as a function of time, the evolution of degree of crystallinity, D(t), was estimated. It was demonstrated that upon heating, D(t) follows the same Avrami curve as the crystallization during cooling. Non-isothermal crystallization observed during slow cooling rates (3K/min ≤ ϕ ≤ 5K/min) is a thermodynamically-controlled process with the energy barrier Ea ≈ 175 kJ/mol; however, the crystallization occurring during fast cooling (5 K/min > ϕ ≥ 30K/min) is driven by a diffusion mechanism, and is characterized by Ea ≈ 305 kJ/mol. The isothermal crystallization taking place in the temperature range 274 K and 281 K is determined by nucleus formation.

Membranes studied using neutron scattering and NMR

1995 ◽  
Vol 73 (11-12) ◽  
pp. 687-696 ◽  
Author(s):  
Myer Bloom ◽  
Thomas M. Bayerl
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Neutron Scattering ◽  
Spectral Characteristics ◽  
Nmr Relaxation ◽  
Elastic Neutron ◽  
Fluid Membranes ◽  
Dynamical Properties ◽  
Elastic Neutron Scattering ◽  
Complementary Techniques

After reviewing some of the basic measurements that characterize the study of physical properties of matter using neutron scattering and nuclear magnetic resonance (NMR), connections between information obtained in current research on fluid membranes using these two complementary techniques are explored in two major chapters. In the first, the type of information on the structure of fluid membranes obtained from coherent elastic neutron scattering is compared with that from NMR spectral characteristics. Then, the type of information obtained on dynamical properties from NMR relaxation (T1 and T2) measurements is compared with that from quasi-elastic neutron scattering. Examples of such connections are given with an emphasis on relationships between the time and distance scales intrinsic to neutron scattering and NMR.

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