Study of the Effects of Different Ambient Gases and Buoyancy on Hydrogen Jet Characteristics.

Substituting nitrogen with inert gases in an inert gas cycle engine can not only effectively improve engine efficiency but also eliminate NOX emissions in the combustion products. Owing to the low density of hydrogen, jet development is affected by buoyancy. This study explored the effects of different ambient gases, such as Ar, N2, and He, as well as buoyancy, on the hydrogen jet and mixing characteristics based on Schlieren. The results indicated that as the pressure ratio increases, the penetration length and volume of the hydrogen jet increase, whereas the dispersion angle and entrainment ratio decrease. The penetration capacity of the hydrogen jet is strongest in He, followed by N2, and weakest in Ar. Additionally, in He, the hydrogen jet exhibits the smallest dispersion angle, fastest jet volume growth, and largest entrainment ratio. The entrainment ratio of the H2 jet in He is 2.75-3.84 times that of N2 and 4.72-8.3 times that of Ar. In N2 and Ar, the penetration length of the inverted jet after 2.5 ms is approximately 2-4 mm longer than that of the upright jet, indicating that buoyancy has a certain influence on jet development.

Interfacial Adhesion between Fatty Acid Collectors and Hydrophilic Surfaces: Implications for Low-Rank Coal Flotation.

Fatty acids, which are enriched in vegetable oil, have attracted much attention in low-rank coal flotation because of their unique chemical structure. In this study, density functional theory calculations, molecular dynamics simulations, and atomic force microscopy were employed to investigate the adsorption structure and forces between collectors and hydrophilic surfaces. The results show that fatty acids can be easily adsorbed onto surfaces through hydrogen bonds, and can cover the oxygen sites. The existence of hydration film on hydrophilic surfaces prevented nonpolar molecules from being able to adsorb, while polar fatty acids could adsorb and expel water molecules. The adhesion force between the RCOOH-terminated probe and the surface appeared in the retraction process, which differed significantly from that of the RCH3-terminated probe, indicating that polar fatty acids are more suitable as flotation collectors for low-rank coal than nonpolar hydrocarbon oil. The simulation and AFM test revealed the mechanisms of polar fatty acids, and can provide guidance for low-rank coal flotation applications.

Neuroprotective effects of alkaloids from Piper longum in a MPTP-induced mouse model of Parkinson's disease.

CONTEXT: Alkaloids of Piper longum L. (Piperaceae) (PLA) include piperine and piperlonguminine. Piper longum and piperine have multiple biological properties including antioxidant activity. OBJECTIVE: The present study investigated the neuroprotective effects of PLA in a MPTP-induced mouse model of Parkinson's disease. MATERIALS AND METHODS: PLA was prepared by extracting the dry seed of P. longum using 85% ethanol. Adult male C57BL/6 mice were divided into eight groups of 12 rats each. Experimental and control groups received an equivalent volume of saline, 0.5% CMC-Na, and 0.1% Tween 80, treated groups received oral PLA (30, 60, and 120 mg/kg), other groups treated with piperine (60 mg/kg) or Madopar (50 mg/kg). The PLA prevention group (PLA-Pr) administrated PLA (120 mg/kg) for 1 week before MPTP challenged. Except for the PLA-Pr group, others were treated for seven consecutive weeks. Parkinson's disease was induced by injecting MPTP intraperitoneally (25 mg/kg) twice weekly for five consecutive weeks. Dopaminerigic (DA) neurons and their metabolism were detected by UFLC-MS/MS. Tyrosine hydroxylase (TH)-immunohistochemistry assay and Western blotting were performed. The antioxidant enzymatic levels were determined by kit-based assays. RESULTS: The LD50 value of PLA was determined at 1509 mg/kg of body weight. PLA (60 mg/kg) can significantly increase total movement time and distance (p < 0.05), increase levels of DA (p < 0.05) and DOPAC (p < .05), increase glutathione (GSH) level and superoxide dismutase (SOD) activity (p < 0.05), and decrease the lipid peroxidation of malondiadehycle (MDA) (p < 0.05) in PLA-treated groups as compared with the control group. DISCUSSION AND CONCLUSION: Our results indicate that PLA possesses neuroprotective effects and has ameliorative properties in dopaminergic neurons.