Stearic Acid Group Research Articles

Dietary 18-carbon fatty acid unsaturation improves the muscle fiber development and meat quality of Megalobrama amblycephala

The study aimed to investigate the effects of four fatty acids with the same carbon-chain length and different saturations, stearic acid (SA), oleic acid (OA), linoleic acid (LA), and linolenic acid (LNA), on the growth performance and muscle quality of Megalobrama amblycephala through in vivo and in vitro experiments. A total of 320 fish with similar initial weight (34.97 ± 0.14 g) were randomly fed 3% four kinds of 18-carbon fatty acids with different carbon saturation. Growth performance was assessed at the end of the feeding trial, and samples were collected for the corresponding indicators. Results showed that the weight gain rate (WGR) and specific growth rate (SGR) of unsaturated fatty acids groups were significantly increased (P < 0.05) than the SA group. Meanwhile, unsaturated fatty acids resulted in a significant increase in white muscle texture (hardness, adhesiveness, gumminess, and chewiness) (P < 0.05). With the increase of fatty acid unsaturation, the number of muscle fibers and density were significantly increased (P < 0.05), while the sarcomere length decreased. The gene expression of sirt1 and camk were significantly up-regulated in unsaturated fatty acids groups (P < 0.05), and the genes related to muscle fiber development were also increased significantly (P < 0.05). In vitro study, the primary muscle cells of Megalobrama amblycephala were treated for 24 h according to the references. The results showed that 250 μmol of unsaturated fatty acids OA, LA, and LNA significantly up-regulated the protein levels of p-Ampk, Camk, and Pax7 associated with muscle fiber development (P < 0.05). In conclusion, unsaturated fatty acids can promote muscle fiber development and meat quality because of the different saturations, which may be realized by activating AMPK and Ca2+-dependent signal pathways.

Rapid dipping preparation of robust Zn(OH)2@STA nanosheet coating on cotton fabric for multifunctional high efficient oil-water separation

A simple, cost-effective, eco-friendly and rapid dipping technique is developed to fabricate the robust superhydrophobic and superoleophilic Zn(OH)2@STA nanosheet coating on cotton fabric surface. When the precursor solution including solvent of anhydrous ethanol and the stearic acid (STA) is dipped onto the cotton fabric surface, with the solvent evaporation of anhydrous ethanol, the precipitated STA from solvent is directly modified on each Zn(OH)2 nanosheet which is formed through chemical reaction in precursor solution, and then the Zn(OH)2@STA nanosheets are closely packed cotton fabric surface, which endows the coating large porosity and is beneficial for the oil-water separation. Meantime, the strong adhesion between the nanosheet coating and fabric is achieved by the esterification reaction of the STA and hydroxyl groups on the cotton fabric surface, which has been verified by a series of mechanical stability test. In various harsh environments, the coating also exhibits the excellent thermal and light irradiation stability, corrosion resistances of acid/alkali and NaCl solution, self-cleaning ability in muddy water and the fire resistance. Finally, in the oil-water separation, the coating on cotton fabric can not only effectively realize the oil-water separation by adsorption oil both floating on water surface and in water, but also can be used for oil filtration in water with efficiency of about 99.8 % and the oil flux of 1515 L/(m2⋅h).

Effects of degree of substitution on stearic acid-modified Bletilla striata polysaccharides nanoparticles and interactions between nanoparticles and bovine serum albumin

Three kinds of stearic acid (SA)-modified Bletilla striata polysaccharides (BSPs-SA) conjugates with different degrees of substitution (DS) values of SA moiety were synthesized. The impacts of the DS values on the properties of BSPs-SA self-aggregated nanoparticles were determined. The interactions between bovine serum albumin (BSA) and the BSPs-SA nanoparticles were characterized using spectroscopic observations. The cytotoxicity was measured through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method. The critical aggregation concentration and the average particle sizes reduced from 16.81μg/mL to 3.09 μg/mL and 192.70 nm to 125.29 nm when the DS values of SA segment increased from 4.98% to 12.94%, respectively. The cumulative release percentage of docetaxel in BSPs-SA nanoparticles decreased whereas encapsulation efficiency and loading capacity increased along with the DS increase of SA moiety. The fluorescence and ultraviolet results demonstrated that the conformation of BSA did not show significant change after incubating with BSPs-SA nanoparticles. Besides, the mass ratio of BSA/BSPs-SA affected their affinity intensity. The inhibition capability of cell proliferation of docetaxel-loaded BSPs-SA nanoparticles against 4T1 was superior to that of Duopafei®. BSPs-SA nanoparticles may become a promising nanocarrier for anticancer drugs by adjusting the DS values of the hydrophobic SA groups.

Surface Modification Mechanism of Stearic Acid to Zirconia Powders Induced by Ball Milling for Water-Based Injection Molding

In conventional process of ceramic injection molding, wax-based binders could only be removed by thermal or organic solvent debinding. Recently, water solvent debinding has appeared as a good alternative owing to its high efficiency and environmental friendliness. In present work, we have demonstrated the surface modification mechanism of stearic acid (SA) to zirconia powders induced by a prior ball-milling treatment before the blending process. Layers of SA with various thicknesses coated around the zirconia powders have been achieved with different amount of SA after the treatment, agreeing well with the theoretically calculated values. The coating is disclosed to be an esterification occurring between the carboxyl group of SA and hydroxyl group of zirconia surface. It plays an important role in limiting agglomeration of ceramic powders and changing the nature of powder surface from hydrophilicity to hydrophobicity, which decreases the shear viscosity of the feedstock and makes the water-debound compact process-compatible with few phase separation. In addition, a significantly faster water-debinding rate was obtained.

Detrimental effects of post-treatment with fatty acids on brain injury in ischemic rats

Studies have illustrated that fatty acids, especially polyunsaturated fatty acids (PUFA), have a role in regulating oxidative stress via the enhancement of antioxidative defense capacity or the augmentation of oxidative burden. Elevated oxidative stress has been implicated in the pathogenesis of brain injury associated with cerebral ischemia/reperfusion (I/R). The objective of this study was to assess whether treatment with fatty acids after focal cerebral I/R induced by occlusion of the common carotid arteries and the middle cerebral artery has effects on brain injury in a rat model. PUFA, including arachidonic acid (AA) and docosahexaenoic acid (DHA), and the saturated fatty acid, stearic acid (SA), were administrated 60 min after reperfusion via intraperitoneal injection. AA and DHA aggravated cerebral ischemic injury, which manifested as enlargement of areas of cerebral infarction and increased impairment of motor activity, in a concentration-dependent manner. However, there were no remarkable differences in post-ischemic alterations between the SA and saline groups. The post-ischemic augmentation of injury in AA and DHA treatment groups was accompanied by increases in the permeability of the blood–brain barrier (BBB), brain edema, metalloproteinase (MMP) activity, inflammatory cell infiltration, cyclooxygenase 2 (COX-2) expression, caspase 3 activity, and malondialdehyde (MDA) production, and by a decrease in the brain glutathione (GSH) content. Furthermore, we found that either AA or DHA alone had little effect on free radical generation in neuroglia, but they greatly increased the hydrogen peroxide-induced oxidative burden. Taken together, these findings demonstrate the detrimental effect of PUFA such as AA and DHA in post-ischemic progression and brain injury after cerebral I/R is associated with augmentation of cerebral I/R-induced alterations, including oxidative changes.

Role of Stearic Acid in Preparing EPDM/Clay Nanocomposites by Melt Compounding

EPDM/organic clay (OC) nanocomposites were prepared by melt blending. XRD results showed that if OC mixed with EPDM matrix, macromolecule chains are difficult to intercalate into the layers while stearic acid (SA) could easily intercalate into the OC interlayers under pretreating conditions (S-OC) and expand the interlayer spacing 2.6 nm of OC to a wider distance of 3.9 nm; EPDM could not further expand the distance of S-OC during the followed mixing process and the structure SA intercalating into OC is kept. TEM observation showed S-OC improved the dispersion of OC in EPDM, and FT-IR results indicated the esterification reaction occurred between carboxyl groups of SA and hydroxyl groups of OC, which was believed to be the driving force of SA intercalation. The tensile strengths of the nanocomposites are improved with increasing amount of SA, and the stresses at low strain are almost the same, due to the physical interaction between OC and EPDM macromolecules.

Neoplastic and preneoplastic lesions induced by melamine in rat urothelium are modulated by dietary polyunsaturated fatty acids

The modulatory effects of polyunsaturated fatty acids (PUFA) on urinary tract tumorigenesis of 275 Wistar rats were evaluated by treating animals with the tumorigenic agent melamine. Rats were fed with formulae containing 6% of 4 varieties of fats: fish oil enriched in n-3 PUFA (FO), corn oil enriched in n-6 (CO), olein containing mainly n-9 oleic acid (O), and 98% stearic acid (SA), the latter two being essential (EFA)-deficient inducers. Two commercially fed control groups with (CM) and without (C) melamine were used. Animals were autopsied at 22–25 and at 36–40weeks. Hepatic fatty acids showed that O and SA groups were EFA-deficient. Simple well differentiated hyperplasias were significantly higher in the FO lot, whereas dysplasia was increased in the CO, O and SA lots. Most of the animals fed for 36–40weeks with the three latter formulae developed the more severe lesions. Increased urothelial proliferation was more frequent in EFA-deficient rats. The apoptosis/mitosis ratio was higher in O, SA and CO fed animals with respect to FO and chow ones. Results show that dietary PUFA modulate differentially both normal and pre-neoplastic urothelial proliferation induced by melamine. FO, rich in n-3 fatty acids, showed a strong protective effect.