A quantitative method was developed to characterize the short-range order in non-crystalline starch by Raman spectroscopy. The Raman spectra of three forms of non-crystalline starches (just-gelatinized starch, which was heated to the point of having just lost its long-range order but still retaining essentially all of its short-range order, gelatinized starch and amorphous starch) were resolved into subspectra to calculate the short-range ordered phases. By deducting the spectra of amorphous starch using a subtraction technique, the areas of subspectra for short-range ordered phases in just-gelatinized and gelatinized starches were obtained. The ratio of the area for short-range ordered phases in gelatinized starch relative to that in just-gelatinized starch was negatively correlated with water content for gelatinization. Based on this, we propose that this ratio of areas provides a quantitative measure for assessing the short-range order in non-crystalline starch. This study provides an alternative and simpler method to an X-ray diffraction protocol proposed previously.
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http://dx.doi.org/10.1016/j.carbpol.2024.121890 | DOI Listing |
Nat Commun
January 2025
Department of Polymer Science and Engineering, Key Laboratory of High-Performance Polymer Materials and Technology of MOE, State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering, Nanjing University, Nanjing, China.
Overheating remains a major barrier to chip miniaturization, leading to device malfunction. Addressing the urgent need for thermal management promotes the development of solid-state electrocaloric cooling. However, enhancing passive heat dissipation through two-dimensional materials in electrocaloric polymers typically compromises the electrocaloric effect.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
January 2025
Institute of Chemistry, Military University of Technology, Kaliskiego 2, PL-00908 Warsaw, Poland.
Molecular arrangement in the chiral smectic phases of the glassforming (S)-4'-(1-methylheptylcarbonyl)biphenyl-4-yl 4-[7-(2,2,3,3,4,4,4-heptafluorobutoxy) heptyl-1-oxy]benzoate is investigated by X-ray diffraction. An increased correlation length of the positional short-range order in the supercooled state agrees with the previous assumption of the hexatic smectic phase. However, the registered X-ray diffraction patterns are not typical for the hexatic phases.
View Article and Find Full Text PDFNat Mater
January 2025
2nd Physics Institute, University of Stuttgart, Stuttgart, Germany.
The shape of biological matter is central to cell function at different length scales and determines how cellular components recognize, interact and respond to one another. However, their shapes are often transient and hard to reprogramme. Here we construct a synthetic cell model composed of signal-responsive DNA nanorafts, biogenic pores and giant unilamellar vesicles (GUVs).
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Institute of Biomedical Chemistry, Pogodinskaya Str., 10, Moscow 119121, Russia.
Biomacromolecules generally exist and function in aqueous media. Is it possible to estimate the state and properties of molecules in an initial three-dimensional colloidal solution based on the structure properties of biomolecules adsorbed on the two-dimensional surface? Using atomic force microscopy to study nanosized objects requires their immobilization on a surface. Particles undergoing Brownian motion in a solution significantly reduce their velocity near the surface and become completely immobilized upon drying.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Department of Chemistry, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
The effect of solution pH on the formation and surface structure of 2-pyrazinethiolate (2-PyzS) self-assembled monolayers (SAMs) formed by the adsorption of 2-mercaptopyrazine (2-PyzSH) on Au(111) was investigated using scanning tunneling microscopy (STM) and X-ray photoelectron microscopy (XPS). Molecular-scale STM observations clearly revealed that 2-PyzS SAMs at pH 2 had a short-range ordered phase of (2√3 × √21)R30° structure with a standing-up adsorption structure. However, 2-PyzS SAMs at pH 8 had a very unique long-range ordered phase, showing a "ladder-like molecular arrangement" with bright repeating rows.
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