The response of starches of different botanical origin to heating in 78% N-methyl morpholine N-oxide (NMMO) is compared with their behaviour in water. For all starches studied an exothermic transition is obtained in the NMMO system rather than the endothermic transition in water. In NMMO the transition temperatures are lower for A-type starches (wheat, rice and tapioca) than the C-type starches (sago and pea) and also potato which has a B-type polymorph. Observations using a hot stage microscope show two different types of initial behaviour in NMMO; erosion of the granule from the surface or disruption into fragments. In both cases the final outcome is dissolution but for the most resistant C-type starches (pea and sago) some intact granules could be seen following heating at 95 °C in 78% NMMO and subsequent precipitation in ethanol. The results are discussed in terms of what is known from previous structural studies on these six starches and the behaviour of maize starch in NMMO and ionic liquids. The work is relevant to the co-dissolution of starch and cellulose to form novel polysaccharide based materials.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.carbpol.2014.06.060 | DOI Listing |
J Inorg Biochem
March 2025
Department of Molecular and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 7-8, H-6720 Szeged, Hungary. Electronic address:
Schiff bases derived from aminoguanidine are extensively investigated for their structural versatility. The tridentate 2-formylpyridine guanylhydrazones act as analogues of 2-formyl or 2-acetylpyridine thiosemicarbazones, where the thioamide unit is replaced by the guanidyl group. Six derivatives of 2-formylpyridine guanylhydrazone were synthesized and their proton dissociation and complex formation processes with Cu(II), Fe(II) and Fe(III) ions were studied using pH-potentiometry, UV-visible, NMR and electron paramagnetic resonance spectroscopic methods.
View Article and Find Full Text PDFCNS Neurosci Ther
December 2024
Department of Anesthesiology, The Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, China.
Background: Esketamine (ESK), a noncompetitive antagonist of N-methyl-D-aspartate (NMDA) receptors, modulates neurotransmitter signaling in the central nervous system. However, the specific mechanisms and therapeutic potential of ESK for intracerebral hemorrhage (ICH) remain unclear. This study aimed to investigate whether ESK promotes nerve repair and improves neurological outcomes in an experimental model of ICH.
View Article and Find Full Text PDFCarbohydr Polym
January 2025
Polymer Science and Engineering Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, Maharashtra, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India. Electronic address:
Dissolution of cellulose without further derivatization has been an active area of research in recent years. There are still challenges in developing a commercially viable solvent system for the dissolution and regeneration of cellulose as films and fibres. We report here a process for making cellulose fibres through the dry-jet wet spinning method by utilizing aqueous zwitterionic liquid (ZIL), viz.
View Article and Find Full Text PDFNaunyn Schmiedebergs Arch Pharmacol
October 2024
Riphah Institute of Pharmaceutical Sciences, Riphah International University, Islamabad, 46000, Pakistan.
Periodic epileptic episodes are the hallmark of epilepsy, a prevalent neurological disorder. Research suggests a significant correlation between neuroinflammation and oxidative stress in a variety of neurological diseases, such as epilepsy. A substantial amount of evidence supports the role of N-methyl-D-aspartate receptors (NMDARs) in the progression of epilepsy.
View Article and Find Full Text PDFACS Omega
October 2024
Department of Fiber System Engineering, Yeungnam University, Gyeongsan 38541, South Korea.
Herein, cellulose pulp (CP), carboxymethyl cellulose (CMC), and thymol-based eco-friendly, transparent, and flexible composite films are prepared. These materials dissolved well in an environment-friendly process in -methyl morpholine -oxide (NMMO) ionic liquids using infrared heating. Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) analyses are used to study the structure, microstructure, and morphology of the composite films.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!