Filament L1482 in the California molecular cloud

Aims. The process of gravitational fragmentation in the L1482 molecular filament of the California molecular cloud is studied by combining several complementary observations and physical estimates. We investigate the kinematic and dynamical states of this molecular filament and physical properties of several dozens of dense molecular clumps embedded therein. Methods. We present and compare molecular line emission observations of the J=2--1 and J=3--2 transitions of 12CO in this molecular complex, using the KOSMA 3-meter telescope. These observations are complemented with archival data observations and analyses of the 13CO J=1--0 emission obtained at the Purple Mountain Observatory 13.7-meter radio telescope at Delingha Station in QingHai Province of west China, as well as infrared emission maps from the Herschel Space Telescope online archive, obtained with the SPIRE and PACS cameras. Comparison of these complementary datasets allow for a comprehensive multi-wavelength analysis of the L1482 molecular filament. Results. We have identified 23 clumps along the molecular filament L1482 in the California molecular cloud. All these molecular clumps show supersonic non-thermal gas motions. While surprisingly similar in mass and size to the much better known Orion molecular cloud, the formation rate of high-mass stars appears to be suppressed in the California molecular cloud relative to that in the Orion molecular cloud based on the mass-radius threshold derived from the static Bonnor Ebert sphere. Our analysis suggests that these molecular filaments are thermally supercritical and molecular clumps may form by gravitational fragmentation along the filament. Instead of being static, these molecular clumps are most likely in processes of dynamic evolution.Comment: 10 pages, 9 figures, 2 tables, accepted to Astronomy and Astrophysic

The relation of H2CO, 12CO, and 13CO in molecular clouds

Aims. We seek to understand how the 4.8 GHz formaldehyde absorption line is distributed in the MON R2, S156, DR17/L906, and M17/M18 regions. More specifically, we look for the relationship among the H2CO, 12CO, and 13CO spectral lines. Methods. The four regions of MON R2 (60'x90'), S156 (5'0x70'), DR17/L906 (40'x60'), and M17 /M18 (70'x80')were observed for H2CO (beam 10'), H110a recombination (beam 10'), 6 cm continuum (beam 10'), 12CO (beam 1'), and 13CO (beam 1'). We compared the H2CO,12CO,13CO, and continuum distributions, and also the spectra line parameters of H2CO,12CO, and 13CO. Column densities of H2CO,13CO, and H2 were also estimated. Results. We found out that the H2CO distribution is similar to the 12CO and the 13CO distributions on a large scale. The correlation between the 13 CO and the H2CO distributions is better than between the 12CO and H2CO distributions. The H2CO and the 13CO tracers systematically provide consistent views of the dense regions. T heir maps have similar shapes, sizes, peak positions, and molecular spectra and present similar centr al velocities and line widths. Such good agreement indicates that the H2CO and the 13CO arise from similar regions.Comment: 21 pages, 12 figures published, 201

Pharmacokinetics and pharmacodynamics of a novel Acetylcholinesterase Inhibitor, DMNG-3

DMNG-3 (3β-Methyl-[2-(4-nitrophenoxy)ethyl]-amino]con-5-enine), is a new and the potentially most potent acetylcholinesterase inhibitor recently obtained from conessine by N-demethylation and nucleophilic substitution reaction. In the present study, a step‑down passive avoidance test was used to investigate whether DMNG-3 could modulate impairment of learning and memory induced by scopolamine, and a high performance liquid chromatography (HPLC) method for the determination of DMNG-3 in biological samples was applied to study its pharmacokinetics and tissues distribution. Separation was achieved on C18 column using a mobile phase consisting methanol‑water (70:30, v/v) at a flow rate of 1.0 ml/min. The intra- and inter-day precisions were good and the RSD was all lower than 1.30%. The mean absolute recovery of DMNG-3 in plasma ranged from 88.55 to 96.45%. Our results showed oral administration of DMNG-3 (10, 25, 50 mg/kg/day) can significantly improve the latency and number of errors and had a positive effect of improvement of learning and memory in mice in passive avoidance tests. The elimination half-life (T1/2) was 14.07±1.29, 15.87±1.03 h, and the total clearance (CL) values were 0.70±0.11, 0.78±0.13 L/h/kg, respectively. The pharmacokinetic studies showed that DMNG-3 has a slowly clearance and large distribution volume in experimental animals, and its disposition is linear over the range of doses tested. The liver, small intestine, stomach, and large intestine were the major distribution tissues of DMNG-3 in mice. It was found that DMNG-3 could be detected in brain, suggesting that DMNG-3 can cross the blood-brain barrier. The present study shows that DMNG-3 can be possible developed as a new drug for the treatment of Alzheimer's disease in the future

Effect of 15 days −6° head-down bed rest on microbial communities of supragingival plaque in young men

IntroductionThe microgravity environment astronauts experience during spaceflight can lead to an increased risk of oral diseases and possible changes in oral microecology. In this study, we aimed to assess changes in the microbial community of supragingival plaques to explore the effects of spaceflight microgravity environment on oral microecology.MethodsSixteen healthy male volunteers were recruited, and supragingival plaque samples were collected under −6° head-down bed rest (HDBR) at five-time points: day 1 before HDBR; days 5, 10, and 15 of HDBR; and day 6 of recovery. Bacterial genomic DNA was sequenced using gene sequencing technology with 16S ribosomal ribonucleic acid V3–V4 hypervariable region amplification and the obtained data were analyzed bioinformatically.ResultsAlpha diversity analysis showed a significant increase in species richness in supragingival plaque samples on day 15 of HDBR compared with that at pre-HDBR. Beta diversity analysis revealed that the community composition differed among the groups. Species distribution showed that, compared with those at pre-HDBR, the relative abundances of Corynebacterium and Aggregatibacter increased significantly during HDBR, while those of Veillonella, Streptococcus, and Lautropia decreased significantly. Moreover, compared with those at pre-HDBR, the relative abundance of Leptotrichia increased significantly on day 6 of recovery, whereas the relative abundances of Porphyromonas and Streptococcus decreased significantly. Network analysis showed that the interaction relationship between the dominant genera became simpler during HDBR, and the positive and negative correlations between them showed dynamic changes. Phylogenetic investigation of communities by reconstruction of unobserved states analysis showed that the amino acid metabolism function of plaque microorganisms was more enriched during HDBR.DiscussionIn summary, in a 15-day simulated microgravity environment, the diversity, species distribution, interaction relationship, and metabolic function of the supragingival plaque microbial community changed, which suggests that microgravity may affect the oral microecosystem by changing the balance of supragingival plaque microbial communities and further leading to the occurrence and development of oral diseases