Near-mid infrared spectroscopy of carbonaceous chondrites: Insights into spectral variation due to aqueous alteration and thermal metamorphism in asteroids

Carbonaceous chondrites (CCs) are windows into the early Solar system and the histories of their parent bodies. Their infrared spectral signatures are powerful proxies for deciphering their composition and evolution history, but still present formidable challenges. In our study, we delved into the infrared spectra spanning 1-25 micron of 17 CCs, with distinct petrological characteristics and varying degrees of alteration. As aqueous alteration intensifies, the 3 micron-region absorption feature associated with OH-bearing minerals and water, and the 6 micron band indicative of water molecules, both grow in intensity. Simultaneously, their band centers shift towards shorter wavelengths. Moreover, as alteration progresses, a distinctive absorption feature emerges near 2.72 micron, resembling the OH absorption feature found in serpentine and saponite minerals. Comparison of aqueous alteration to laboratory-heated CCs suggests that the 3 micron region OH/H2O absorption feature differs between CC heated to less than or more than ~300C. The 12.4 micron/11.4 micron reflectance ratio diminishes, and the reflectance peak in the 9-14 micron range shifts towards shorter wavelengths. These changes are attributed to the transformation of anhydrous silicates into phyllosilicates. In the 15-25 micron region, the influence of thermal metamorphism becomes evident and results in the appearance of more spectral features, the single reflectance peak at 22.1 micron undergoes a transformation into two distinct peaks at 19 micron and 25 micron, which is primarily attributed to the increased presence of anhydrous silicates and olivine recrystallization. These findings offer novel insights into the volatile-rich compositions of C-complex asteroids and the thermal evolution histories of their parent bodies.Comment: Accepted by Icarus, 7028 total words, 11 figures, 1 tabl

Characterization of DNA Methylation Associated Gene Regulatory Networks During Stomach Cancer Progression

DNA methylation plays a critical role in tumorigenesis through regulating oncogene activation and tumor suppressor gene silencing. Although extensively analyzed, the implication of DNA methylation in gene regulatory network is less characterized. To address this issue, in this study we performed an integrative analysis on the alteration of DNA methylation patterns and the dynamics of gene regulatory network topology across distinct stages of stomach cancer. We found the global DNA methylation patterns in different stages are generally conserved, whereas some significantly differentially methylated genes were exclusively observed in the early stage of stomach cancer. Integrative analysis of DNA methylation and network topology alteration yielded several genes which have been reported to be involved in the progression of stomach cancer, such as IGF2, ERBB2, GSTP1, MYH11, TMEM59, and SST. Finally, we demonstrated that inhibition of SST promotes cell proliferation, suggesting that DNA methylation-associated SST suppression possibly contributes to the gastric cancer progression. Taken together, our study suggests the DNA methylation-associated regulatory network analysis could be used for identifying cancer-related genes. This strategy can facilitate the understanding of gene regulatory network in cancer biology and provide a new insight into the study of DNA methylation at system level

Vegetative Ecological Characteristics of Restored Reed (Phragmites australis) Wetlands in the Yellow River Delta, China

In this study, we compared ecological characteristics of wetland vegetation in a series of restoration projects that were carried out in the wetlands of Yellow River Delta. The investigated characteristics include plant composition structure, species diversity and community similarity in three kinds of Phragmites australis wetlands, i.e. restored P. australis wetlands (R1, R2, R3 and R4: restored in 2002, 2005, 2007 and 2009, respectively), natural P. australis wetland (N) and degraded P. australis wetland (D) to assess the process of wetlands restoration. The coverage of the R1 was 99%, which was similar to natural wetland. Among all studied wetlands, the highest and lowest stem density was observed in R1 and R2, respectively, Plant height and stem diameter show the same trend as N > R2 > R1 > R3 > D > R4. Species diversity of restored P. australis wetlands became closed to natural wetland. Both species richness and Shannon–Wiener index had similar tendency: increased first and then decreased with restored time. The highest species richness and species diversity were observed in R2, while the lowest values of those parameters were found in natural P. australis wetland. Similarity indexes between restored wetlands and natural wetland increased with the restoration time, but they were still less than 50%. The results indicate that the vegetation of P. australis wetlands has experienced a great improvement after several years’ restoration, and it is feasible to restored degraded P. australis wetlands by pouring fresh water into those wetlands in the Yellow River Delta. However, it is notable that costal degraded P. australis wetland in this region may take years to decades to reach the status of natural wetland

The Double-Lumen Irrigation-Suction Tube in The Management of Incisional Surgical Site Infection After Enterocutaneous Fistula Excisions: An Observational Study

Background This study aimed to investigate the effect of double-lumen irrigation-suction tube (DLIST) in the management of surgical site infections (SSIs) after enterocutaneous fistula (ECF) excisions. Method From January 2016 to December 2017 medical records of patients with ECF excisions were reviewed. Patients with primary superficial SSI were divided into group a (treated with DLIST) and b (treated with delayed primary closures). Patients with primary deep SSI were divided into group A (treated with DLIST) and B (treated with vacuum-assisted closure [VAC]). The effect of the DLIST was evaluated. Results There were 32 in group a and 27 in group b. The therapeutic time and cost in group a were lower (13.13 ± 2.37 d vs. 24.89 ± 7.44 d; p < .001; $1456 ± 302 vs.$2784 ± 583; p < .001). There were 21 in group A and 23 in group B. While the therapeutic time of group A was longer, the cost was lower ($1717 ± 404 vs.$2636 ± 592; p < .001). Conclusions Placing DLIST is an effective and cheap method to treat superficial SSI after ECF excisions. The cost of DLIST in treatment of deep SSI is lower, while the effect of VAC is better

Global estimates of lunar iron and titanium contents from the Chang' E-1 IIM data

Until recently, global high spatial resolution maps of FeO and TiO2 of the Moon were only derived from Clementine data. In this study, we show global maps of FeO and TiO2 using Chang'E-1 Interference Imaging Spectrometer (IIM) at a spatial resolution of 200 m/pixel. With a newly developed calibration presented here, spectra obtained by IIM compare well with telescopic spectra. Spectral parameters previously shown to be sensitive to iron and titanium, derived from the calibrated IIM data are highly correlated with the measured elemental concentration with R-2 = 0.96 for FeO and 0.95 for TiO2. The maps were developed using this calibration. Histograms of basalt FeO estimates have a negatively skewed distribution, while TiO2 distributions are unimodal. They also revealed that the lunar highland crust is relatively uniform on the quadrant scale (several hundred to thousand kilometers scale) but inhomogenous on the global scale. The area of highest elevation of the Moon has very low FeO and TiO2 raising the question about South Pole-Aitken (SPA) (whether its ejecta deposits covered the highest elevation and when it was formed). Although the average FeO and TiO2 abundances for basalts are highly correlated, local areas of elevated iron can be associated with both high and low titanium