Space debris detection in optical image sequences.

We present a high-accuracy, low false-alarm rate, and low computational-cost methodology for removing stars and noise and detecting space debris with low signal-to-noise ratio (SNR) in optical image sequences. First, time-index filtering and bright star intensity enhancement are implemented to remove stars and noise effectively. Then, a multistage quasi-hypothesis-testing method is proposed to detect the pieces of space debris with continuous and discontinuous trajectories. For this purpose, a time-index image is defined and generated. Experimental results show that the proposed method can detect space debris effectively without any false alarms. When the SNR is higher than or equal to 1.5, the detection probability can reach 100%, and when the SNR is as low as 1.3, 1.2, and 1, it can still achieve 99%, 97%, and 85% detection probabilities, respectively. Additionally, two large sets of image sequences are tested to show that the proposed method performs stably and effectively.

Two new conjugated ketonic fatty acids from the stem bark of Juglans mandshurica.

The present study was designed to isolate and characterize novel chemical constituents of the stem bark of Juglans mandshurica Maxim. (Juglandaceae). The chemical constituents were isolated and purified by various chromatographic techniques. The structures of the compounds were elucidated on the basis of spectral data (1D and 2D NMR, HR-ESI-MS, CD, UV, and IR) and by the comparisons of spectroscopic data with the reported values in the literatures. Two long chain polyunsaturated fatty acids (1 and 2) were obtained and identified as (S)-(8E,10E)-12-hydroxy-7-oxo-8,10-octadecadienoic acid (1) and (S)-(8E, 10E)-12-hydroxy-7-oxo-8,10-octadecadienoic acid methyl ester (2). To the best of our knowledge, this is the first report on the isolation and structural elucidation of the two new conjugated ketonic fatty acids from this genus.

Chemical constituents from the aerial parts of Melandrium firmum.

Two new anthraquinones, melrubiellin C (1) and melrubiellin D (2), were isolated from the aerial parts of Melandrium firmum Rohrbach, together with eight known compounds (3-10). The structures of these compounds were elucidated using 1D and 2D NMR (COSY, HMQC, HMBC and NOESY) experiments. All isolated compounds were tested for their cytotoxicity against NCI-H460, Hep G2, MKN-28 and A-549 cells. Of these 10 compounds, 1 and 2 exhibited moderate cytotoxicity with IC50 values ranging from 9.54 to 32.41 µM.

Cytotoxic anthraquinone dimers from Melandrium firmum.

Two new anthraquinone dimers, melrubiellin A (1) and melrubiellin B (2), were isolated from the aerial part of Melandrium firmum Rohrbach, along with seven known compounds (3-9). The structures of these compounds were elucidated by spectral analyses, including 1D and 2D NMR (COSY, HMQC, HMBC and NOESY) experiments. Compound 1 and 2 exhibited significant cytotoxicity towards HeLa, NCI-H460, Hep G2, Hep 3B and MKN-28 cell lines with IC50 values ranging from 5.26 to 81.16 µM.

A new phenyl glycoside from the aerial parts of Equisetum hyemale.

A new phenyl glycoside, 2-(sophorosyl)-1-(4-hydroxyphenyl)ethanone (9), was isolated from the ethanolic extract of the aerial parts of Equisetum hyemale L., together with eight known compounds (1-8). The structures of these compounds were elucidated using a combination of spectroscopic analyses and chemical method. Of these nine compounds, 4 and 7 showed hepatoprotective effects towards tacrine-induced cytotoxicity in Hep 3B cells with EC50 values of 42.7 ± 1.5 and 132.6 ± 2.8 µM, respectively.

A new phenolic glycoside from Juglans mandshurica.

A new phenolic glycoside, 6-O-(4'-hydroxy-3',5'-dimethoxybenzoyl)-d-glucopyranose (4), and nine known compounds (1-3 and 5-10) were isolated from Juglans mandshurica Maxim. Compound structures were elucidated by NMR, HR-ESI-MS and acid hydrolysis. Compounds 5 and 6 are reported from this genus for the first time. Among compounds 1-10, only 1 exhibited cytotoxicity against MGC-803, A549, K562, JAR, HeLa, CaSKi and SiHa cell lines (IC50: 2.0, 5.3, 2.3, 6.9, 4.0, 6.6 and 2.7 µM, respectively).