Oxidation of cornstarch using oxygen as oxidant without catalyst

In the present work, oxygen was used as an environmentally friendly oxidant without catalyst, resulting in a waste free and simple method for starch oxidation. The oxidation was performed under the conditions of oxygen in sodium hydroxide at about 100 °C. It was found that the oxidation of the native cornstarch in this system depends upon the amount of sodium hydroxide, the temperature and the duration of the oxidation treatment. Twenty one gram NaOH, 100 °C and 3.0 h are the optimum conditions for getting the desirable water-soluble oxidized starch with carboxyl content of 3.6 g/100 g. The microstructure of oxidized cornstarch was characterized by scanning electron microscopy (SEM), Fourier transform-infrared (FT-IR), Carbon-13 nuclear magnetic resonance spectroscopy (¹³C NMR) and chemical analysis methods. The results showed that the oxidation reaction introducing carboxyl and carbonyl groups took place at OH groups of C2, C3 and C6 in the glucose units and did not cause the breakage of C-O-C linkages.     

The ether lipid inositol-C2-PAF is a potent inhibitor of cell proliferation in HaCaT cells

The search for specific anticancer drugs that do not interfere with DNA synthesis or influence the cytoskeleton has led to the development of modified phospholipids with antiproliferative properties. These compounds cause remodeling of the structure and function of plasma membranes. Recently, we described novel compounds, the glycosidated phospholipids, that surprisingly inhibit cell proliferation. These compounds contain alpha-D-glucose in the sn-2 position of the glycerol backbone of phosphatidylcholine (PC) and platelet-activating factor (PAF), which gives rise to 2-glucophosphatidylcholine (Glc-PC) and 1-O-octadecyl-2-O-alpha-d-glucopyranosyl-sn-2-glycero-3-phosphatidylcholine (Glc-PAF), respectively. Glc-PC and Glc-PAF inhibit the growth of HaCaT cells at nontoxic concentrations. Here we report the introduction of myo-inositol, in place of alpha-D-glucose, in the sn-2 position of the glycerol backbone; this leads to two diastereomeric 1-O-octadecyl-2-O-(2-(myo-inositolyl)-ethyl)-sn-glycero-3-(R/S)-phosphatidylcholines (Ino-C2-PAF). The inositol-containing PAF enhances the antiproliferative capacity (IC(50)=1.8 microM) and reduces the cytotoxicity relative to Glc-PAF (LC(50)=15 microM). Through biological assays, we showed that, in HaCaT cells, Ino-C2-PAF causes upregulation of the keratinocyte-specific differentiation marker involucrin, increases the activity of the differentiation marker transglutaminase, and induces apoptosis at nontoxic concentrations. Ino-C2-PAF therefore seems to be a promising candidate for development as an antiproliferative drug for the treatment of hyperproliferative diseases of the skin.     

A nanoscale qualitative study on the role of sodium hydrosulfide in oxidized carrollite flotation

The surface species transformation of oxidized carrollite processing with NaHS and KBX was investigated. Flotation and contact angle tests indicate that the combination of NaHS and KBX takes a better flotation performance than adding NaHS or KBX alone. Thermodynamic analysis, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) results confirm the stronger chemisorption of KBX occurs on the oxidized carrollite surface with NaHS, which is beneficial to remove the cobalt oxides, thus contributing to the superior floatability. Interestingly, less elemental sulfur was observed on the carrollite surface as the interaction of NaHS and KBX than adding NaHS alone. It suggests that elemental sulfur is not the main contributor to the restored floatability of oxidized carrollite through sulfidisation. This study provided a new perspective to correlate the surface species with xanthate adsorption and oxidized carrollite flotation through determining the various intermediate products.     

联合法制取大豆磷脂新工艺的研究

研究了溶剂萃取油脚制取大豆磷脂的新工艺,确定了较好的工艺条件,溶剂1的萃取次数:3～5次,溶剂2的萃取次数:4～6次,萃取时间:20～60min.大豆磷脂的收率达到了85%.     

一种铝合金压铸蜡乳液脱模剂的研制

研究了用氧化聚乙烯蜡、58#全炼蜡制备铝合金压铸蜡乳液脱模剂的方法。考查了乳化剂类型、乳化剂用量、乳化工艺对乳液稳定性的影响。实验结果表明,当复合乳化剂用量为复合蜡的30%,乳化温度为95℃,搅拌速度为500~700 r/min时,乳化时间为40~45 min,可以制取一种稳定的用于铝合金压铸蜡乳液脱模剂。     

Effects of ion-exchanged calcium, barium and magnesium on cross-linking reactions during direct liquefaction of oxidized lignite

In this work the influences of alkaline earth metals on cross-linking reactions (CLRs) during direct liquefaction of lignite were investigated. The oxidized lignite, which has been proved to be appropriate for quantitatively examine the extent of CLR during direct liquefaction, was used as a model coal to study the effects of ion-exchanged calcium, barium and magnesium on CLR during direct liquefaction of the oxidized lignite. The amounts of tetrahydrofuran (THF) insoluble solid products after liquefaction were used to quantitatively evaluate the CLR during liquefaction of the ion-exchanged coal. The results show that the oxidized coal is appropriate to quantitatively examine the extent of CLR and the targeted ions are exchanged to the oxidized coal in the form of highly-dispersed ion. The ion-exchanged Mg^2 + suppresses the CLR during direct liquefaction of coal at both low and high temperature. However, the exchanged Ca^2 + always promotes the CLR at the selected temperatures. While the exchanged Ba^2 + promotes the CLR at low temperature, but suppresses it at high temperature.     

Extraction of egg-yolk lecithin

In this research, the extraction of egg-yolk lecithin with ethanol was studied. Extraction was performed with deoiled and undeoiled yolks and with heated and unheated yolks. The yield of the extracted fraction relative to the initial material, phospholipid (PL) purity, and cholesterol content of both the PC-enriched fractions and the remaining PL fractions were determined. The yield and PL purity of the PC-enriched fractions obtained from the undeoiled yolks were 23.9 and 35.7%, and those obtained from deoiled yolks were 13.5 and 53.3%. The recovery of total PL in the two fractions was higher from the undeoiled (70%) than from the deoiled yolks (60%). However, heating had a negligible effect on PL extraction. Better enrichment of PC was observed by extraction from the undeoiled than from the deoiled yolks. The cholesterol content of the PC-enriched fraction obtained from the undeoiled yolks was much higher than that from the deoiled yolks.     

Nucleoside-based phospholipids and their liposomes formed in water

Phospholipids and liposomes have been the subjects of considerable attention because of their importance in biological systems. We have efficiently synthesized novel nucleoside-based phospholipids in six-step sequences starting from their corresponding nucleosides. These nucleoside-based phospholipids self-assemble into liposome-like structures in aqueous solutions. We have analyzed the structures of these liposomes by dynamic light scattering, transmission electron microscopy, and confocal microscopy.     

Fatty acid composition of melon seed oil lipids and phospholipids

Fatty acid compositions of crude melon seed oil from two different sources were compared. Melon seeds fromCitrullus vulgaris (syn.C. lanatus) contained phosphatidylcholine (PC), lysophosphatidylcholine (LPC) and phosphatidylserine (PS), whereas melon seeds fromCitrullus colocynthis contained only PC and LPC, but not PS. Analysis of the total lipids revealed that the major fatty acid of the oils was 18:2n-6.Citrullus vulgaris seed oil contained 71.3% andC. colocynthis contained 63.4% of 18:2n-6. The predominant fatty acids in theC. vulgaris PC were 18:2n-6 (32.2%), 18:1n-9 (26.4%) and 16:0 (22.2%), whereas theC. colocynthis PC contained 44.6% of 18:1n-9 as the major fatty acid. The level of monoenes in theC. colocynthis variety (46.2%) was different from theC. vulgaris (27.3%). The major fatty acid in the LPC was 18:1n-9 for both varieties. Notably, theC. colocynthis variety did not contain any PS. The major fatty acids in theC. vulgaris PS were 18:1n-9 (37.9%) and 18:2n-6 (33.7%). Of all the phospholipids, LPC contained the greatest amount of monoenes, 48.6–52.4%.