The Aquilaria sinensis (Lour.) Gilg (CX)–Aucklandia costus Falc. (MX) herbal pair is frequently used in traditional Chinese medicine prescriptions for treating depression. The volatile oil from CX and MX has been shown to have good pharmacological activities on the central nervous system, but its curative effect and mechanism in the treatment of depression are unclear. Therefore, the antidepressant effect of the volatile oil from CX–MX (CMVO) was studied in chronic unpredictable mild stress (CUMS) rats. The suppressive effects of CMVO (25, 50, 100 μL/kg) against CUMS-induced depression-like behavior were evaluated using the forced swimming test (FST), open field test (OFT) and sucrose preference test (SPT). The results showed that CMVO exhibited an antidepressant effect, reversed the decreased sugar preference in the SPT and prolongation of immobility time in the FST induced by CUMS, increased the average speed, time to enter the central area, total moving distance, and enhanced the willingness of rats to explore the environment in the OFT. Inhalational administration of CMVO decreased levels of adrenocorticotropic hormone and corticosterone in serum and the expression of corticotropin-releasing hormone mRNA in the hypothalamus, which indicated regulation of over-activation of the hypothalamic–pituitary–adrenal (HPA) axis. In addition, CMVO restored levels of 5-hydroxytryptamine (5-HT), dopamine, norepinephrine and acetylcholine in the hippocampus. The RT-PCR and immunohistochemistry results showed that CMVO up-regulated the expression of 5-HT1A mRNA. This study demonstrated the antidepressant effect of CMVO in CUMS rats, which was possibly mediated via modulation of monoamine and cholinergic neurotransmitters and regulation of the HPA axis.

Large eddy simulation and FW-H acoustic analogy method are performed to investigate the effect of serrated leading edge on rod-airfoil interaction (RAI) noise. A NACA 0012 airfoil with straight and serrated leading edge at zero angle of attack is located one chord length behind a cylinder rod. The leading edge serrations are in the form of sinusoidal profiles .The free stream Mach number is 0.2 and the Reynolds number based on the rod diameter is 48,000. Firstly, the numerical results of straight leading edge airfoil are compared with experimental data, both the flow field predictions and the acoustic results are in good agreement with experiment. Secondly, the numerical results are compared between straight and serrated airfoils. The wake of the serrated airfoil is a little bit narrower and weaker and the leading edge serrations efficiently reduce the span-wise correlation coefficient. There is almost no noise reduction effect below the Karman vortex shedding frequency. The reduction of SPL at the Karman vortex shedding frequency is about 2.4 dB. A significant noise reduction is achieved by the serrations over a quite wide frequency range between 2 KHz and 6.5 KHz. It can be noted that the OASPL directivities at different azimuth angles all reduced 2-5.5 dB due to the serrations, which means than the leading serrations are an effective passive flow control method to reduce RAI noise. NomenclatureA = amplitude of the leading edge serration W = wavelength of the leading edge serration c = baseline airfoil chord lenght c(z) = serrated airfoil chord length c = serrated airfoil mean chord length d = cylinder rod diameter L span = span-wise length of the experiment L sim = span-wise length of the simulation R = radius of the observer points around the airfoil a 0 = free stream speed of sound 0  = free stream dendity U 0 = free stream velocity 2 u mean = stream-wise mean velocity RMS = root mean square rms u = root mean square of stream-wise velocity fluctuation rms p = root mean square of pressure fluctuation f 0 = Karman vortex shedding frequency St = Strouhal number C L = lift coefficient of the airfoil C D = drag coefficient of the airfoil C P = pressure coefficient SPL = sound pressure level PWL = sound power level PSD = power spectral density OASPL = overall sound pressure level FFT = fast Fourier transform

Background. The Citrus aurantium- (ZhiShi, ZS-) Rhizoma Atractylodis Macrocephalae (BaiZhu, BZ) pairs are often found in herbal formulas for constipation. The volatile oils of ZS and BZ (ZBVO) have good pharmacological activity against constipation, but the mechanism for treatment of slow transit constipation (STC) remains unclear. Method. A rat model using diphenoxylate tablets was constructed to investigate if transdermal administration of ZBVO would mediate intestinal microorganisms and fecal metabolites and improve STC symptoms. The regulatory effects of ZBVO at 0.15, 0.30, and 0.60 mL kg-1 d-1 on STC rats were assessed by measuring fecal water content, intestinal propulsion rate, histopathology, expression of gastrointestinal hormones, brain and intestinal peptides, and inflammatory factors. The changes in intestinal flora of STC rats were analyzed by 16S rRNA gene sequencing. Moreover, the untargeted fecal metabolomics analysis was performed by ultraperformance liquid chromatography quadrupole time-of-flight mass spectrometer (UPLC-Q-TOF-MS) technology. Results. The results showed that ZBVO had a modulating effect on STC by increasing the fecal water content and intestinal propulsion rate. Transdermal administration of ZBVO decreased serum levels of interleukin 6 (IL-6) and tumor necrosis factor-α (TNF-α) and increased the levels of gastrin (GAS) and substance P (SP). In addition, ZBVO increased 5-hydroxytryptamine (5-HT) levels and decreased vasoactive intestinal peptide (VIP) levels in colon and hippocampus tissues. The results of intestinal microbiota showed that ZBVO improved the diversity and abundance of intestinal microbiota and changed the community composition by decreasing Romboutsia and increasing Proteobacteria, Allobaculum, and Ruminococcaceae. And the feces metabolomics found that nicotinate and nicotinamide metabolism, purine metabolism, citrate cycle (TCA cycle), pyruvate metabolism, arachidonic acid metabolism, pyrimidine metabolism, and primary bile acid biosynthesis were modulated. Conclusion. These findings suggest that ZBVO can alleviate STC symptoms by promoting intestinal peristalsis, increasing fecal water content, regulating gastrointestinal hormone level, reducing the inflammatory response, and regulating brain and intestinal peptides after transdermal administration. And structural changes in the intestinal microbiota are closely related to host metabolism and intestinal microbiota destroyed in STC modeling could be significantly improved by the ZBVO, which provides a reference for the development of aromatic drug macrohealth products.

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