Silicone antifoam performance enhancement by nonionic surfactants in potato medium

The ability of a silicone antifoam to retard foaming in a liquor prepared from potatoes is enhanced by the addition of ethoxylated nonionic surfactants. The enhancement is non-linear for surfactant concentration, with all 12 surfactants tested possessing a concentration at which foam heights strongly diminish, referred to as the surfactant critical antifoaming concentration (SCAFC). SCAFCs vary between surfactants, with lower values indicating better mass efficiency of antifoaming enhancement. SCAFCs decrease with degree of ethoxylation and decrease with the hydrophilic–lipophilic balance for ethoxylated nonionic surfactants. Surfactant addition produces a mixed water-surface layer containing surfactant and surface-active components in the potato medium. Surface tension reduction does not correlate well with antifoam performance enhancement. A model is proposed where surfactant adsorption promotes desorption of surface-active potato medium components from the water surface. At the SCAFC, desorption is not complete, yet the rate of bubble rupture is sufficiently enhanced to provide excellent foam control. Electronic Publication     

The identification of foam-forming soluble proteins from wheat (Triticum aestivum) dough

Proteomic methods have been used to identify foam-forming soluble proteins from dough that may play an important role in stabilising gas bubbles in dough, and hence influence the crumb structure of bread. Proteins from a soluble fraction of dough (dough liquor) or dough liquor foam have been separated by two-dimensional gel electrophoresis, and 42 identified using a combination of matrix-assisted laser desorption/ionization-time of flight and quadrupole-time of flight analyses. Major polypeptide components included beta-amylase, tritin and serpins, with members of the alpha-amylase/trypsin inhibitor family being particularly abundant. Neither prolamin seed storage proteins nor the surface-active protein puroindoline were found. Commonly used dough ingredients (NaCl, Na L-ascorbate) had only a minor effect on the 2-DE protein profiles of dough liquor, of which one of the more significant was the loss of 9 kDa nonspecific lipid transfer protein. Many proteins were lost in dough liquor foam, particularly tritin, whilst a number of alpha-amylase inhibitors were more dominant, suggesting that these are amongst the most strongly surface-active proteins in dough liquor. Such proteins may play a role determining the ability of the aqueous phase of doughs, as represented by dough liquor, to form an elastic interface lining the bubbles, and hence maintain their integrity during dough proving.     

Hyperlipidemia is a major determinant of neointimal formation in LDL receptor-deficient mice

LDL receptor-deficient (LDLR(-/-)) mice exhibit mild hyperlipidemia on a chow diet but develop severe hyperlipidemia on a high fat diet. In this study, we investigated neointimal formation after removal of the endothelium when LDLR(-/-) mice were fed chow or a Western diet containing 42% fat, 0.15% cholesterol, and 19.5% casein. At 10 weeks of age, female mice underwent endothelial denudation of the left common carotid artery. Two weeks after injury, neointimal formation was barely detectable in the injured vessel when mice developed mild hyperlipidemia on the chow diet. In contrast, neointimal lesions were obvious when mice developed severe hyperlipidemia on the Western diet. Immunohistochemical and histological analyses demonstrated the presence of macrophage foam cells and smooth muscle cells in neointimal lesions. The injured artery also exhibited a significant increase in medial area on the Western diet. Plasma levels of MCP-1 and soluble VCAM-1 were significantly elevated by feeding of the Western diet. These data indicate that hyperlipidemia aggravates neointimal growth in LDLR(-/-) mice by promoting foam cell formation and inflammation.     

A novel surrogate lung material for impact studies: Development and testing procedures

This work focuses on the development of a surrogate lung material (SLM) that reproduces the dynamic response of a human lung under various loading conditions and also allows for the analysis of the extent and distribution of damage. The SLM consists of polyurethane foam used to mimic the spongy lung tissue and fluid-filled gelatine microcapsules used to simulate the damage of alveoli.The bursting pressure of the microcapsules was investigated by conducting low and high rate compression tests on single microcapsules. A bursting pressure of around 5 bar was measured which is comparable to the reported lung overpressure at injury level.Low and high rate compression tests were conducted on the SLMs. From the measured mechanical properties and mass density, the stress wave speed was calculated and found to be well in the range of the reported values for human lungs (16–70 m/s).In order to study the extent and distribution of damage in the SLMs, as represented by burst microcapsules, a CT scan analysis was carried out before and after the impacts. The CT scan results clearly demonstrated the magnitude and distribution of damage within the specimen. The results are then compared to the Bowen curves, the most often used criteria for predicting blast injuries in humans. An excellent agreement was found between the observed damage in the surrogate lungs and the expected damage in real human lungs.In general, the SLM showed similar stress wave speed, bursting pressure and damage to that of the real lungs.     

Perilipin and adipophilin expression in lipid loaded macrophages

Lipid-filled macrophages (foam cells) are a defining feature of atherosclerotic plaques. Foam cells contain lipid droplet-associated proteins that in other cell types regulate lipid turnover. In foam cell such proteins may directly affect lipid droplet formation and lipid efflux. Differentiated primary human monocytes or THP-1 cells were lipid loaded by incubation with aggregated low density lipoproteins (AgLDL) or VLDL resulting in macrophage foam cells with predominantly cholesterol ester or triglyceride-rich lipid droplets, respectively. Lipid droplets were isolated and major proteins identified by mass spectrometry, among them the apolipoprotein B-48 receptor that has not previously been recognized in this context. Expression of two proteins, perilipin and adipophilin, was quantified by Western blots of cell lysates. Perilipin content decreased and adipophilin increased with lipoprotein lipid loading regardless of intracellular neutral lipid composition. This protein expression pattern may hinder lipid turnover in macrophage foam cells, thereby increasing lipid content of atherosclerotic plaques.     

Lipid reducing activity of novel cholic acid (CA) analogs: Design,synthesis and preliminary mechanism study

Bile acids, initially discovered as endogenous ligands of farnesoid X receptor (FXR), play a central role in the regulation of triglyceride and cholesterol metabolism and have recently emerged as a privileged structure for interacting with nuclear receptors relevant to a large array of metabolic processes. In this paper, phenoxy containing cholic acid derivatives with excellent drug-likeness have been designed, synthesized, and assayed as agents against cholesterol accumulation in Raw264.7 macrophages. The most active compound 14b reduced total cholesterol accumulation in Raw264.7 cells up to 30.5% at non-toxic 10 μM and dosage-dependently attenuated oxLDL-induced foam cell formation. Western blotting and qPCR results demonstrate that 14b reduced both cholesterol and lipid in Raw264.7 cells through (1) increasing the expression of cholesterol transporters ABCA1 and ABCG1, (2) accelerating ApoA1-mediated cholesterol efflux. Through a cell-based luciferase reporter assay and molecular docking analysis, LXR was identified as the potential target for 14b. Interestingly, unlike conventional LXR agonist, 14b did not increase lipogenesis gene SREBP-1c expression. Overall, these diverse properties disclosed herein highlight the potential of 14b as a promising lead for further development of multifunctional agents in the therapy of cardiovascular disease.     

应力对大段骨缺损修复影响的实验兔模型探讨

目的 建立用于研究应力对大段骨缺损修复作用的实验兔动物模型.方法 选用20只健康成年大耳白兔,随机分成两组,在右侧肱骨中下段制造13 mm的大段骨缺损后植入泡沫碳化硅人工骨,实验组选用具有固定和持续轴向加压双重作用的镍钛记忆合金接骨器,对照组选用同种材料和规格的仅有固定作用的接骨器,术后常规护理,待取材观察.结果 20只实验兔中,7只在苏醒后当天,10只术后1～3 d,3只术后4～7 d,出现植入体从植入部位脱出游离至皮下现象.结论 用于研究应力对大段骨缺损修复作用的实验兔动物模型未成功建立,镍钛记忆合金接骨器对兔肱骨大段骨缺损处人工骨的固定和持续加载,在实验兔肱骨难以实现.     

Structure and properties of starch-based foams prepared by microwave heating from extruded pellets

The physical properties of microwave-foamed starch-based pellets, including density, porosity, cell structure, water absorption characteristics and mechanical properties were characterized. It was found that the physical properties of these starch-based foams produced by microwave heating are highly dependent on the raw materials and additives. Foam density decreased significantly after addition of 5.5–10.5% w/w salts, while foams containing nucleation agent (talc) were denser than the control with reduced cell size. A proprietary blowing agent did not affect the foam density markedly. Addition of salts also increased the water sorption of foams and plasticized cell walls. Mechanical behaviour of foamed pellets can be adjusted effectively by controlling the cell structure through using different additives. Mechanical properties of the foamed pellets in the elastic region as well as under large deformation (up to 40% strain) all follow a power–law relationship with foam density.     

Evaluation of foam cell formation in cultured macrophages: an improved method with Oil Red O staining and DiI-oxLDL uptake

Macrophage-derived foam cell formation elicited by oxidized low-density lipoprotein (oxLDL) is the hallmark of early atherogenesis. Detection of foam cell formation is conventionally practiced by Oil Red O (ORO) staining of lipid-laden macrophages. Other methods include 1,1′-dioctadecyl-3,3,3′3′-tetra-methylindocyanide percholorate (DiI)-labeled oxLDL (DiI-oxLDL) uptake and Nile Red staining. The purpose of the present study is to report an optimized method for assessing foam cell formation in cultured macrophages by ORO staining and DiI-oxLDL uptake. After incubation with oxLDL (50 μg/ml) for 24 h, the macrophages were fixed, stained with ORO for just 1 min, pronounced lipid droplets were clearly observed in more than 90% of the macrophages. To test the in vivo applicability of this method, lesions (or foam cells) of cryosections of aortic sinus or primary mouse peritoneal macrophages from ApoE deficient mice fed a high cholesterol diet were successfully stained. In another set of experiments, treatment of macrophages with DiI-oxLDL (10 μg/ml) for 4 h resulted in significant increase in oxLDL uptake in macrophages as demonstrated by confocol microscopy and flow cytometry. We conclude that the optimized ORO staining and fluorescent labeled oxLDL uptake techniques are very useful for assessing intracellular lipid accumulation in macrophages that are simpler and more rapid than currently used methods.