木薯淀粉磷酸单酯的性质及结构

木薯淀粉磷酸单酯的性质及结构;木薯淀粉磷酸单酯;理化性质;结构表征     

298.16 K Na＋, K＋, Mg2＋//Cl－, NO3－-H2O五元体系的相平衡研究

采用等温溶解平衡法研究了五元体系Na^＋, K^＋, Mg^2＋//Cl^－, NO₃^－-H₂O在298.16 K、氯化钠饱和时各盐的溶解度和饱和溶液的物化性质(密度, 电导率)以及四元体系Na^＋, Mg^2＋//Cl^－, NO₃^－-H₂O的相平衡关系. 研究表明: 在298.16 K, 氯化钠饱和时该五元体系溶解度相图由六个结晶区、九条单变量溶解度曲线和四个零变量点构成, 六个结晶区分别对应于NaNO₃＋NaCl, KNO₃＋NaCl, KCl＋NaCl, Mg(NO₃)₂•6H₂O＋NaCl, MgCl₂•6H₂O＋NaCl和复盐KCl•MgCl₂•6H₂O＋NaCl; 在298.16 K时, 该四元体系的相图由四个结晶区、五条单变量溶解度曲线和二个零变量点构成, 四个结晶区分别对应于NaNO₃, NaCl, Mg(NO₃)₂•6H₂O, MgCl₂•6H₂O.     

Lactic Acid-Based Natural Deep Eutectic Solvents to Extract Bioactives from Marine By-Products

Natural deep eutectic solvents (NaDES) were used to extract bioactive compounds from marine by-products: codfish bones, mussel meat, and tuna vitreous humor. NaDES were prepared using natural compounds, including lactic acid (Lac), fructose (Fru), and urea (Ur), and were characterized to define their physicochemical properties, including the viscosity, density, surface tension, and refractive index. FTIR and NMR analysis confirmed the presence of intermolecular hydrogen bonding in NaDES. The extracts obtained using these NaDES were characterized to define their composition. Results demonstrated that the extract’s composition differed highly, depending not only on the DES used, but also on the structure and composition of the raw material. Proteins and lipids were mainly present in extracts obtained from mussels, while ash content was highest in the extracts obtained from codfish bones. The biocompatibility of NaDES and the soluble fractions (SF) of the raw materials in NaDES was evaluated, and it was possible to conclude that the soluble ingredients obtained from the raw materials improved the biocompatibility of NaDES.     

Preparation and characterization of bioactive oils nanoemulsions: Effect of oil unsaturation degree,emulsifier type and concentration

The effect of formulation parameters namely oil type, emulsifier type and concentration was assessed on various properties of the nanoemulsions. All nanoemulsions yielded droplets with a desirable size ranged from 38.5 to 127.9?nm. The findings showed that emulsifier type had significant effects on the physicochemical properties of emulsions. Emulsifier concentration had a negative correlation with droplet diameter, turbidity and positive correlation with polydispersity index, viscosity and creaming stability. Nanoemulsions prepared from pomegranate seed oil were different from that of two other oils in droplet size, viscosity, creaming and turbidity because of its higher intrinsic viscosity and degree of unsaturation.     

Estimation of active conformations of drugs by a new molecular superposing procedure

We have developed a new program, SUPERPOSE, to superpose two molecules based on the physicochemical properties of functional atoms within individual molecules. SUPERPOSE treats a pseudo-molecule consisting of functional atoms instead of a real molecule. Four types of physicochemical properties – hydrophobicity, presence of a hydrogen-bonding donor, presence of a hydrogen-bonding acceptor and presence of a hydrogen-bonding donor/acceptor – were supposed and a score was given to each overlap. When functional atoms with the same physicochemical properties were overlapped, points were added to the score, and when the functional atoms with different physicochemical properties were overlapped, points were subtracted. We applied SUPERPOSE to 12 pairs of 24 enzyme inhibitors and found that the best scored overlay for each inhibitor pair could successfully reproduce the superposition obtained from X-ray crystallography. Next, we applied SUPERPOSE to estimate the active conformations of the thrombin inhibitors MQPA, 4-TAPAP and NAPAP. Superpositions of conformers sampled by the high-temperature molecular dynamics calculation with respect to the three inhibitors were performed, and 13 sets of conformers having the best common overlay to the three inhibitors were selected. One among 13 sets was consistent with the superposition of the active conformations derived from the X-ray crystallography of the thrombin–inhibitor complexes.     

Polyurethanes containing sulfur. I. New thermoplastic polyurethanes with benzophenone unit in their structure

New thermoplastic nonsegmented thiopolyurethanes were obtained from the low-melting aliphatic–aromatic thiodiols 4,4′-bis(2-hydroxyethylthiomethyl)benzophenone (BHEB), 4,4′-bis(3-hydroxypropylthiomethyl)benzophenone (BHPB), and 4,4′-bis(6-hydroxyhexylthiomethyl)benzenophenone(BHHB) as well as hexamethylene diisocyanate (HDI), both by melt and solution polymerization with dibutyltin dilaurate as the catalyst. The effect of various solvents on molecular-weight values was examined. The polymers with the highest reduced viscosities (0.63–0.88 dL/g) were obtained when the polymerization was carried out in a solution of tetrachloroethane, N,N-dimethylacetamide, and N,N-dimethylacetamide or N,N-dimethylformamide for BHEB-, BHPB-, and BHHB-derived polyurethanes, respectively. These polymers with a partially crystalline structure showed glass-transition temperatures (T_g) in the range of −1 to 39 °C, melting temperatures (T_m) in the range of 107 to 124 °C, and thermal stabilities up to 230 to 240 °C. The BHEB-derived polyurethane is a low-elasticity material with high tensile strength (ca. 50 MPa), whereas the BHPB- and BHHB-derived polyurethanes are more elastic, showing yield stress at approximately 16 MPa. We also obtained segmented polyurethanes by using BHHB, HDI, and 20 to 80 mol % poly(oxytetramethylene) glycol (PTMG) of M̄_n = 1000 as the soft segment. These are high-molecular thermoplastic elastomers that show a partially crystalline structure. Thermal properties were investigated by thermogravimetric analysis and differential scanning calorimetry. The increase in PTMG content decreases the definite T_g and increases the solubility of the polymers. These segmented polyurethanes exhibit the definite T_g (−67 to −62 °C) nearly independent of the hard-segment content up to approximately 50 wt %, indicating the existence of mainly phase-separated soft and hard segments. Shore A/D hardness and tensile properties were also determined. As the PTMG content increases, the hardness, modulus of elasticity, and tensile strength decrease, whereas elongation at break increases. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4140–4150, 1999     

NaVO3-Na3PO4-H2O三元体系的等温相图和平衡液相物化性质测定

钒和磷都是动植物体中的必需元素,在动植物体中起着十分重要而又非常复杂的生理作用。土壤中的钒、磷等元素可通过食物链进入生物体或植物体中,对动植物体都带来一定的影响。适量的钒能促进植物的生长发育,促进植物的固氮、固氯作用;钒累积达到一定程度时,则会对动植物体产生一定的毒理作用。影响动植物体内酶的活性调节、蛋白质的生物合成及遗传过程。     

Part I: NiMoO4 Nanostructures Synthesized by the Solution Combustion Method: A Parametric Study on the Influence of Synthesis Parameters on the Materials’ Physicochemical,Structural, and Morphological Properties

The impact of process conditions on the synthesis of NiMoO₄ nanostructures using a solution combustion synthesis (SCS) method, in which agar powder and Ni(NO₃)₂ were utilized as fuel and as the oxidant, respectively, was thoroughly studied. The results show that the calcination temperature had a significant implication on the specific surface area, phase composition, particle size, band gap, and crystallite size. The influence of calcination time on the resulting physicochemical/structural/morphological properties of NiMoO₄ nanostructures was found to be a major effect during the first 20 min, beyond which these properties varied to a lesser extent. The increase in the Ni/Mo atomic ratio in the oxide impacted the combustion dynamics of the system, which led to the formation of higher surface area materials, with the prevalence of the β-phase in Ni-rich samples. Likewise, the change in the pH of the precursor solution showed that the combustion reaction is more intense in the high-pH region, entailing major implications on the physicochemical properties and phase composition of the samples. The change in the fuel content showed that the presence of agar is important, as it endows the sample with a fluffy, porous texture and is also vital for the preponderance of the β-phase.