Preparation and characterization of calcium phosphate cement with enhanced tissue adhesion for bone defect repair

Anti-washout and tissue adhesion properties are essential for the clinical application of injectable bone materials. In this study, we prepared calcium phosphate cement (CPC) with anti-washout and tissue adhesion properties and attempted to build covalent bonds between CPC and the amino groups in bone tissue under a self-regulating pH system in the CPC (acidic to basic). The results of push-out tests demonstrated that a significant enhancement (from 6.42 ± 0.76 N to 61.5 ± 4.09 N) in tissue adhesion was obtained with the addition of 6% (w/w) oxidized sodium alginate (OSA) in CPC. The FTIR, XRD, anti-washout test, XPS, pH test, and SEM results suggested that the synergistic effect of OSA-citric acid (CA) led to the formation of a three-dimensional gel network structure in the CPC, and the Schiff base reaction between aldehyde and amino groups induced adhesion between CPC and the bone tissue. Further, the addition of less OSA had no significant negative effect on the hydration properties of CPC. Our work aims to promote the development of injectable bone material in clinical applications.     

烃氧化产物皂化后活性组分在油、水相的分配

用强酸酸化后测定乙醚抽出物酸量和酯量、溴甲酚绿两相滴定测定羧酸盐等方法研究了烃氧化产物皂化后活性组分在油、水相的分配。结果表明,在现行的用NaOH皂化烃氧化产物以制备水溶性石油磺酸盐的过程中有相当多的活性组分分配到油相;在水相和油相中均有大量羧酸酯存在,羧酸酯量远远超过羧酸盐量。     

难选氧化锰矿的选别工艺特征

氧化锰矿的泥化现象一般较严重，有的矿石很容易在机械作用下碎裂泥化，并且锰在粗、细粒级中的含量差别较大，因此在选别过程中避免过碎、强搅拌、强擦洗，并利用合理的分级工序，往往能获得十分理想的选别指标。     

H2PO2-的氧化方式与化学镀Ni-P合金历程

硫酸镍-次亚磷酸钠体系中的化学镀反应,是一个在多相体系中进行的复杂物理-化学过程,因此,存在多种关于它的理论或看法.综合目前较为流行的几种理论认为,各种机理理论存在的最大差别在于H2PO2-被氧化方式上的差异.文中还结合自己的研究结果,认为化学沉积Ni-P合金的机理是一个"氢化物-电化学联合机理".     

氧化蜡接枝丙烯酸的改性研究

对丙烯酸接枝熔融氧化蜡进行了研究,分别探讨了反应温度、过硫酸铵质量分数、丙烯酸质量分数、反应时间等因素对熔融氧化蜡的接枝率的影响,确定了合适的丙烯酸接枝熔融氧化蜡的正交工艺条件为:反应温度为85℃,过硫酸铵质量分数为3.5%～4.5%,丙烯酸质量分数为40%,反应时间为3h,最终按照正交实验总结出的优化方案制备出了接枝率、酸值、贮存与离心稳定性等性质优异的改性氧化蜡。     

氧化蜡乳液的研制

采用自制氧化蜡研制氧化蜡乳液,考察了乳化剂的质量分数、乳化温度、搅拌速率、乳化时间等因素对乳液性能的影响,确定了制备氧化蜡乳液的复合乳化剂质量分数以及乳化工艺。实验结果表明,当氧化蜡质量分数15%、乳化剂质量分数3%、乳化剂的亲水亲油平衡值约为12.0、乳化温度85℃、搅拌速率800r/min、乳化时间35min时,可得到稳定性好、分散性为一级的乳白色的氧化蜡乳液。     

Microstructure and elastic modulus of mixed gels of gelatin + oxidized starch: Effect of pH

The microstructure and elastic shear modulus of cold-set gels formed from high-sugar aqueous mixtures of gelatin (7 wt%) + oxidized starch (0-6 wt%) were investigated as a function of pH. Samples prepared at 90 °C, with citric acid added to adjust the pH, were rapidly quenched to ∼1 °C, subjected to a standard thermal treatment (40 °C for 10 min), and then investigated by confocal microscopy and small-deformation rheology at 24 °C. Under ‘natural’ conditions of pH ≈ 5.2 (no citric acid addition), the samples exhibited phase separation with a characteristic spinodal-type morphology. The spatial extent of the structural heterogeneity, expressed by a single length-scale parameter, was found to increase with starch concentration. Gradual acidification led to a reduction in this length-scale parameter, leading to complete inhibition of phase separation below a certain characteristic pH value in the range 4.5-4.9 (depending on starch content). Over the investigated pH range, the effect of starch addition was to reduce the storage modulus of the resulting gel. This reduction was more pronounced for the phase-separated samples. The pH of maximum rigidity was found to decrease from pH_max ≈ 4.6 for 0 wt% starch to pH_max ≈ 4.2 for 6 wt% starch. Taken all together, these observations can be understood in terms of the effects of pH on the cross-linking behaviour of the gelatin and the nature of the gelatin-starch electrostatic interactions. The microscopy results are consistent with a transition in behaviour from thermodynamic incompatibility (segregative interactions) at high pH to soluble complexation (associative interactions) at low pH.     

金精矿超声波强化硝酸预氧化提金研究

本文提出了常压低温下对原生金矿预处量的一种新方法，对于含硫较高的原生矿，采用超声波强化硝酸预氧化处理工艺，处理后的氧化渣采用氰化浸出，金的浸出率同硝酸直接氧化后氰化浸出相比。有显著提高，该方法氧化时间短，对设备要求低，具有一定的生产价值。     

Acid Value,Polar Compounds and Polymers as Determinants of the Efficient Conversion of Waste Frying Oils to Biodiesel

The cost of starting materials for the production of biodiesel is typically 75 % of the final retail price. Oils previously used for frying, waste frying oils (WFO), are a very suitable resource. Repetitive use of oil for frying foods involves high temperature, moisture and aeration for extended periods. The most important deterioration processes triggered by these conditions are hydrolysis and oxidation. In this study, 24 WFO samples of different origins were analyzed and classified as potential starting materials for biodiesel production using three quality parameters representing the main factors that affect the conversion of WFO. These parameters were: acid value, content of polar compounds and content of polymers, which varied in the ranges from 0.2 to 7.6, 14.9 to 43.2 and 0.9 to 15.2 %, respectively. Ester content obtained using conventional transesterification (TE) for WFO conversion decreased with increased levels of WFO deterioration determined by any of the three parameters noted above. TE products obtained had ester content between 81.4 and 95.7 %. Total ester content of a WFO sample with relatively low %AV could be increased to 96.5 % using a two-stage base catalysis TE. Finally, conversion of WFO samples resulted in ester contents of 89.0 and 91.3 %, respectively, when transesterified by conventional TE. After blending up to 10 % with refined oil, the ester content achieved was near 96.5 %. Thus, the blending represents an alternative for obtaining a product with suitable ester content.     

Hydroxyoctadecadienoic Acids Regulate Apoptosis in Human THP‐1 Cells in a PPARγ‐Dependent Manner

Macrophage apoptosis, a key process in atherogenesis, is regulated by oxidation products, including hydroxyoctadecadienoic acids (HODEs). These stable oxidation products of linoleic acid (LA) are abundant in atherosclerotic plaque and activate PPARγ and GPR132. We investigated the mechanisms through which HODEs regulate apoptosis. The effect of HODEs on THP‐1 monocytes and adherent THP‐1 cells were compared with other C18 fatty acids, LA and α‐linolenic acid (ALA). The number of cells was reduced within 24 hours following treatment with 9‐HODE (p < 0.01, 30 μM) and 13 HODE (p < 0.01, 30 μM), and the equivalent cell viability was also decreased (p < 0.001). Both 9‐HODE and 13‐HODE (but not LA or ALA) markedly increased caspase‐3/7 activity (p < 0.001) in both monocytes and adherent THP‐1 cells, with 9‐HODE the more potent. In addition, 9‐HODE and 13‐HODE both increased Annexin‐V labelling of cells (p < 0.001). There was no effect of LA, ALA, or the PPARγ agonist rosiglitazone (1μM), but the effect of HODEs was replicated with apoptosis‐inducer camptothecin (10μM). Only 9‐HODE increased DNA fragmentation. The pro‐apoptotic effect of HODEs was blocked by the caspase inhibitor DEVD‐CHO. The PPARγ antagonist T0070907 further increased apoptosis, suggestive of the PPARγ‐regulated apoptotic effects induced by 9‐HODE. The use of siRNA for GPR132 showed no evidence that the effect of HODEs was mediated through this receptor. 9‐HODE and 13‐HODE are potent—and specific—regulators of apoptosis in THP‐1 cells. Their action is PPARγ‐dependent and independent of GPR132. Further studies to identify the signalling pathways through which HODEs increase apoptosis in macrophages may reveal novel therapeutic targets for atherosclerosis.