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In south China, warm-sector rainstorms are significantly different from the traditional frontal rainstorms due to complex mechanism, which brings great challenges to their forecast. In this study, based on ensemble forecasting, the high-resolution mesoscale numerical forecast model WRF was used to investigate the effect of initial errors on a warmsector rainstorm and a frontal rainstorm under the same circulation in south China, respectively. We analyzed the sensitivity of forecast errors to the initial errors and their evolution characteristics for the warm-sector and the frontal rainstorm. Additionally, the difference of the predictability was compared via adjusting the initial values of the GOOD member and the BAD member. Compared with the frontal rainstorm, the warm-sector rainstorm was more sensitive to initial error, which increased faster in the warm-sector. Furthermore, the magnitude of error in the warm-sector rainstorm was obviously larger than that of the frontal rainstorm, while the spatial scale of the error was smaller. Similarly, both types of the rainstorm were limited by practical predictability and inherent predictability, while the nonlinear increase characteristics occurred to be more distinct in the warm-sector rainstorm, resulting in the lower inherent predictability. The comparison between the warm-sector rainstorm and the frontal rainstorm revealed that the forecast field was closer to the real situation derived from more accurate initial errors, but only the increase rate in the frontal rainstorm was restrained evidently. [ABSTRACT FROM AUTHOR]

16-Isopropyl-5, 9-dimethyltetracyclo [10.2.2.01, 10.04, 9] hexadec-15-ene-5, 14-dicarboxylic acid (1b) was prepared from rosin through a Diels–Alder addition reaction. Then, a group of Schiff bases derived from 1b was synthesised. Their structures were characterised by IR,1H-NMR, MS and elemental analysis. The antibacterial activities of these newly synthesised Schiff bases were also investigated. The results show that these compounds possess antibacterial activities against Staphylococcus aureus and Escherichia coli. Among them, compounds 5a, 5b and 5c, exhibit remarkable antibacterial activity against E. coli. [ABSTRACT FROM AUTHOR]

This paper presents an optical method to determine the scattering characteristics of dielectric rough targets in the terahertz band. Based on the complex permittivity of alloy Al (Aluminum) and painted Al obtained from the reflectance spectra, the analytical bidirectional reflection distribution function (BRDF) spectra of rough surfaces are simulated using physical optics. The effects of surface roughness, complex permittivity, incident angle, and wavelength are analyzed. With the optimization of artificial immune network genetic algorithms, it is demonstrated that the optimized five-parameter BRDF empirical model fits the analytical BRDF spectra over a wide range of incidence angles. Then, the radar cross section (RCS) of electrically large targets can be simulated by the relationship between the differential scattering coefficient and BRDF. The obtained RCS of the rough sphere from optimized BRDF model is in good agreement with the numerical analysis that was obtained. The proposed method is suitable for obtaining the scattering properties of large dielectric targets with different surfaces compared with traditional high-frequency electromagnetic (EM) techniques. The backscattered and bistatic terahertz RCS of a cylinder, cone and NASA almond are simulated. The proposed method shows the potential for the application of BRDF in the areas of scattering analysis and remote sensing. [ABSTRACT FROM AUTHOR]

A new sterol, (23 R )-methoxycholest-5,24-dien-3β-ol ( 1 ), two new ceramides, (2 S ,3 R ,4 E ,8 E )-2-(tetradecanoylamino)-4,8-octadecadien-l,3-diol ( 6 ) and (2 S ,3 R ,2' R ,4 E ,8 E )-2-(tetradecanoylamino)-4,8-octadecadien-l,3,2'-triol ( 7 ), together with three known sterols ( 2 - 4 ), a lactone ( 5 ) and two ceramides ( 8 , 9 ), were isolated from the marine bryozoan Cryptosula pallasiana , collected at Huang Island of China. The structures of the new compounds were elucidated by extensive spectroscopic analyses, chemical methods and quantum electronic circular dichroism (ECD) calculations. Among the isolated compounds, sterol 1 possessed a rare side chain with a methoxy group at C-23, and a double bond between C-24 and C-25. Ceramides 6 and 7 possessed 14 carbons in their long-chain fatty acid base (FAB), which were different from the normal ceramides with 16 carbons in the FAB. Moreover, compounds 5 and 8 were isolated for the first time from marine bryozoans. Compounds 1 - 9 were evaluated for their cytotoxicity against human tumor cell lines HL-60, Hep-G2 and SGC-7901. The results showed that lactone 5 appears to have strong cytotoxicity against the test tumor cell lines, with IC 50 values from 4.12 μM to 7.32 μM, and sterol 1 displayed moderate cytotoxicity with IC 50 values between 12.34 μM and 18.37 μM, while ceramides 6 - 9 showed weak cytotoxicity with IC 50 ranging from 21.13 μM to 58.15 μM.

Two phosphoniobate-based 3D frameworks were firstly constructed using the hexa-capped Keggin polyoxoniobates [PNb12O40(VO)6](3-) and copper cations. Photocatalytic studies indicated that the hybrid materials exhibit photocatalytic hydrogen evolution activity.

16-isopropyl-5, 9-dimethyltetracyclo [10.2.2.0(1, 10).0(4, 9)] hexadec-15-ene-5, 14-dicarboxylic acid (1b) was prepared from rosin through a Diels-Alder addition reaction. Then, a group of Schiff bases derived from 1b was synthesised. Their structures were characterised by IR,(1)H-NMR, MS and elemental analysis. The antibacterial activities of these newly synthesised Schiff bases were also investigated. The results show that these compounds possess antibacterial activities against Staphylococcus aureus and Escherichia coli. Among them, compounds 5a, 5b and 5c, exhibit remarkable antibacterial activity against E. coli.

Skin lesions are often associated with human immunodeficiency virus (HIV) infection, reflecting the immunocompromised status of the individual. We investigated the relationship between skin lesions and immune function in a retrospective study of 796 Chinese HIV patients with and without highly active antiretroviral therapy (HAART). Of the 651 patients who had not received HAART, we found that 531 (81.6%) had apparent skin lesions. The incidence of infectious skin diseases (fungi, viruses, bacteria, spirochetes and parasites) and non-infectious skin diseases (excluding skin cancer) was 68.8% and 34.9%, respectively. Mean CD4(+) T-cell counts and CD4(+)/CD8(+) ratios were lower in patients with skin lesions than in patients without lesions (178 ± 96/µl vs. 306 ± 189/µl (p < 0.05) and 0.22 vs. 0.34 (p < 0.01), respectively). Candidiasis (25.8%), eczema (19.2%), nodular prurigo (13.8%), dermatophyte infections (10.6%) and herpes zoster (9.4%) were most common in Chinese patients with HIV. Among the 145 patients who had started HAART, there was a significantly lower prevalence of skin diseases (29.0%), although drug eruptions (12.4%) were more commonly observed. These findings indicate that HAART often reduces the incidence of infectious and non-infectious skin lesions in patients with HIV, but can itself be the cause of drug eruptions.

The title compound, C(24)H(40)O(3)·C(2)H(6)O, is a substituted tetra-cyclo-[10.2.2.0(1,10).0(4,9)]hexa-decane derivative obtained from the reduction of maleopimaric acid which was isolated from a maleic anhydride modified rosin. In the crystal, the triol mol-ecule and the ethanol solvent mol-ecule are linked by hydroxyl O-H⋯O hydrogen bonds, giving a two-dimensional network structure.

In the crystal structure of the title compound, C(16)H(19)NO, mol-ecules are linked through a pair of N-H⋯O hydrogen bonds, forming chains along the a axis.

The title compound, C(10)H(16)O(3), with a bicyclo-[3.1.1]heptane unit, was obtained by oxidation of β-pinene. The asymmetric unit contains two independent mol-ecules with similar geometry: the six-membered rings in both mol-ecules adopt envelope conformations. In the crystal, the independent mol-ecules exist as O-H⋯O hydrogen-bonded dimers. The dimers are linked into helical chains along the b axis by O-H⋯O hydrogen bonds.