3D seismic analysis of subsurface gas migration and the gas hydrate system offshore Mauritania

3D seismic data are used in this thesis to investigate fluid migration processes and the gas hydrate system offshore Mauritania. The studied interval was deposited during the Neogene, characterised by fine-grained hemipelagic sediments, polygonal faults, mass transport complexes (MTCs), high amplitude anomalies (HAAs), and a widespread bottom simulating reflection (BSR). In the study area, there are many localized HAAs above some MTCs. Their spatial relationship indicates that there was upward gas migration up the margins or local faults associated with the MTCs. One possible gas source could be dissociated hydrates due to the upward resetting of the BSR, but there may be other sources like in situ biogenic gas. At shallower depth, a gravity-driven fault below the BSR acted as a conduit for gas recycling after hydrate dissociation. There is a close spatial relationship among the fault location, a breached gas accumulation and a shallower free gas zone (FGZ), suggesting the process of gas recycling between hydrates and another gas trap. The BSR is investigated which is composed of alternating high and low amplitudes and characterized by amplitude bands on the BSR map. The high amplitude bands are interpreted to be caused by free gas trapped below the base of gas hydrates, potentially in spaced beds of coarser sediments. These amplitude bands provide evidence of lateral changes in the ambient conditions that control the depth of the BSR, including the variable water depth of the slope, impingement of salt diapir and mud volcano, and canyon cutting at the seabed. Generally this thesis exemplifies the potential of 3D seismic data in studying the gas hydrate system and related processes. For example, mapping the BSR on 3D seismic data can show lateral changes of the BSR at different depths from only one map, representing an effective method to study the base of gas hydrates

Gas venting that bypasses the feather edge of marine hydrate, offshore Mauritania

Methane can be released from the vast marine hydrate reservoirs that surround continents into oceans and perhaps the atmosphere. But how these pathways work within the global carbon cycle now and during a warmer world is only partially understood. Here we use 3-D seismic data to identify what we interpret to be a gas venting system that bypasses the hydrate stability zone (HSZ) offshore of Mauritania. This venting is manifested by the presence of the acoustic wipe-out (AWO) across a densely faulted succession above a salt diapir and a set of morphological features including a substantial, ∼260 m wide and ∼32 m deep, pockmark at the seabed. The base of the HSZ is marked by a bottom simulating reflector (BSR) which deflects upwards above the diapir, rather than mimicking the seabed. We use a numerical modelling to show that this deflection is caused by the underlying salt diapir. It creates a trapping geometry for gas sealed by hydrate-clogged sediment. After entering the HSZ, some methane accumulated as hydrate in the levees of a buried canyon. Venting in this locality probably reduces the flux of gas to the landward limit of feather edge of hydrate, reducing the volume of gas that would be susceptible for release during a warmer world

The Airlines’ Recent Experience Under the Railway Labor Act

Silky-feather has been selected and fixed in some breeds due to its unique appearance. This phenotype is caused by a single recessive gene (hookless, h). Here we map the silky-feather locus to chromosome 3 by linkage analysis and subsequently fine-map it to an 18.9 kb interval using the identical by descent (IBD) method. Further analysis reveals that a C to G transversion located upstream of the prenyl (decaprenyl) diphosphate synthase, subunit 2 (PDSS2) gene is causing silky-feather. All silky-feather birds are homozygous for the G allele. The silky-feather mutation significantly decreases the expression of PDSS2 during feather development in vivo. Consistent with the regulatory effect, the C to G transversion is shown to remarkably reduce PDSS2 promoter activity in vitro. We report a new example of feather structure variation associated with a spontaneous mutation and provide new insight into the PDSS2 function

Bioassay-guided isolation of three new alkaloids from Suillus bovinus and preliminary mechanism against ginseng root rot

In order to control the occurrence of ginseng root rot caused by Fusarium solani (Mart.) Sacc., the antifungal compounds of the mushroom Suillus bovinus were investigated. And three new alkaloids (1–3), named bovinalkaloid A–C, along with one known analog (4), were isolated and identified by bioassay-guided isolation and spectroscopic analyses. Compound 1 strongly inhibited the mycelial growth and spore germination of F. solani with minimum inhibitory concentration of 2.08 mM. Increases in electrical conductivity, nucleic acid, and protein contents, and decreases in lipid content showed that the membrane permeability and integrity were damaged by compound 1. Compound 1 also increased the contents of malondialdehyde and hydrogen peroxide and the activities of antioxidant enzymes, indicating that lipid peroxidation had taken place in F. solani. Compound 1 may serve as a natural alternative to synthetic fungicides for the control of ginseng root rot

Prognostic value of the ascites characteristics in pseudomyxoma peritonei originating from the appendix

BackgroundPseudomyxoma peritonei (PMP) is a rare disease, with the overall survival (OS) influenced by many factors. To date, no ascites characteristics have been reported to predict OS of patients with PMP. The present study therefore aims to describe the ascites characteristics for PMP and identify prognostic factors for survival.MethodsBetween June 2010 and June 2020, 473 PMP patients who underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy were included in a retrospective study. Survival analysis was performed with the Kaplan–Meier method by the log-rank test and a Cox proportional hazards model. Associations between categorical variables were analyzed using the chi-squared test.ResultsAmong all included patients, 61% were women. The median OS was 47 months (range, 4–124 months) at the last follow-up in December 2020. Ascites characteristics can be divided into light blood ascites, “Jelly” mucus ascites, and faint yellow and clear ascites. Multivariate Cox analysis showed that the degree of radical surgery, ascites characteristics, and pathological grade were independently associated with OS in PMP patients. The chi-squared test documented that faint yellow “Jelly” ascites were related to low-grade PMP and light blood ascites were associated with high-grade PMP (P < 0.01).ConclusionsLight blood ascites, incomplete cytoreduction surgery, and high-grade histopathology may predict poor OS in appendix-derived PMP

Records of East Asian monsoon activities in Northeastern China since 15.6 ka, based on grain size analysis of peaty sediments in the Changbai Mountains

Peatlands provide a widespread terrestrial archive for Holocene study. However, little is known about the grain-size characteristics of peaty sediments and their environmental significance. In order to study these phenomena in detail, two sections from the Hani and Gushantun peatlands in the Changbai Mountain Area were cored and sub-sampled. Based on reliable calibrated AMS 14C ages, we established grain size variations in the peat cores since 15.6 ka cal. BP. Our results showed that the peaty sediments in the Changbai Mountains are mainly composed of silt. Moreover, the grain size component, which is related to paleoclimate variables, can be classified into three groups based on the “Grain size class vs. standard deviation” method. These sensitive grain size components are <37.0 mm (Component 1 or C1), 37.0e497.8 mm (Component 2 or C2) and >497.8 mm (Component 3 or C3). C1 comprises the finest silt in the peaty sediment and is mainly conveyed by the East Asian winter monsoon (EAWM), whereas C2 is transported into the peatland by surface runoff related to the enhancement of the East Asian summer monsoon (EASM). C3 is conveyed in saltation and bed-load mode by strong surface runoff linked to highenergy flow caused by a strong EASM, and perhaps is an indicator of extreme rainfall events in the Changbai Mountains. Our results suggest that the study region was dominated by a cold/dry environment during the late-glacial period under a strong EAWM. However, there was a marked climatic shift from an EAWM-dominated cold/dry climate to an EASM-dominated more mesic environment during the early Holocene. Increased percentage of C2 in peat cores during the Holocene Optimum (9.0e4.5 ka) indicates abundant rainfall in the study region (even with extreme rainfall events) as a result of a significant enhancement of the EASM. Weak monsoon events occurred at 10.5 ka, 9.2 ka, 8.2 ka, 7.2 ka, 6.2ka, 5.5 ka and 4.2 ka shown by sharp decreases in C2, agreeing with the stalagmite d18O records in China. The results obtained from environmentally sensitive grain-size component records are largely consistent with other palaeoenvironmental records in the East Asian monsoon area, substantiating the regional climate patterns and monsoon evolution since late-glacial time. Because intensity of the East Asian monsoon is likely responsible for the grain-size change in the peat samples, the grain size components in peat samples may be used for reconstructions of past environmental conditions and of variability in the East Asian monsoon

Mechanism of Bazhen decoction in the treatment of colorectal cancer based on network pharmacology, molecular docking, and experimental validation

ObjectiveBazhen Decoction (BZD) is a common adjuvant therapy drug for colorectal cancer (CRC), although its anti-tumor mechanism is unknown. This study aims to explore the core components, key targets, and potential mechanisms of BZD treatment for CRC.MethodsThe Traditional Chinese Medicine Systems Pharmacology (TCMSP) was employed to acquire the BZD’s active ingredient and targets. Meanwhile, the Drugbank, Therapeutic Target Database (TTD), DisGeNET, and GeneCards databases were used to retrieve pertinent targets for CRC. The Venn plot was used to obtain intersection targets. Cytoscape software was used to construct an “herb-ingredient-target” network and identify core targets. GO and KEGG pathway enrichment analyses were conducted using R language software. Molecular docking of key ingredients and core targets of drugs was accomplished using PyMol and Autodock Vina software. Cell and animal research confirmed Bazhen Decoction efficacy and mechanism in treating colorectal cancer.ResultsBZD comprises 173 effective active ingredients. Using four databases, 761 targets related to CRC were identified. The intersection of BZD and CRC yielded 98 targets, which were utilized to construct the “herb-ingredient-target” network. The four key effector components with the most targets were quercetin, kaempferol, licochalcone A, and naringenin. Protein-protein interaction (PPI) analysis revealed that the core targets of BZD in treating CRC were AKT1, MYC, CASP3, ESR1, EGFR, HIF-1A, VEGFR, JUN, INS, and STAT3. The findings from molecular docking suggest that the core ingredient exhibits favorable binding potential with the core target. Furthermore, the GO and KEGG enrichment analysis demonstrates that BZD can modulate multiple signaling pathways related to CRC, like the T cell receptor, PI3K-Akt, apoptosis, P53, and VEGF signaling pathway. In vitro, studies have shown that BZD dose-dependently inhibits colon cancer cell growth and invasion and promotes apoptosis. Animal experiments have shown that BZD treatment can reverse abnormal expression of PI3K, AKT, MYC, EGFR, HIF-1A, VEGFR, JUN, STAT3, CASP3, and TP53 genes. BZD also increases the ratio of CD4+ T cells to CD8+ T cells in the spleen and tumor tissues, boosting IFN-γ expression, essential for anti-tumor immunity. Furthermore, BZD has the potential to downregulate the PD-1 expression on T cell surfaces, indicating its ability to effectively restore T cell function by inhibiting immune checkpoints. The results of HE staining suggest that BZD exhibits favorable safety profiles.ConclusionBZD treats CRC through multiple components, targets, and metabolic pathways. BZD can reverse the abnormal expression of genes such as PI3K, AKT, MYC, EGFR, HIF-1A, VEGFR, JUN, STAT3, CASP3, and TP53, and suppresses the progression of colorectal cancer by regulating signaling pathways such as PI3K-AKT, P53, and VEGF. Furthermore, BZD can increase the number of T cells and promote T cell activation in tumor-bearing mice, enhancing the immune function against colorectal cancer. Among them, quercetin, kaempferol, licochalcone A, naringenin, and formaronetin are more highly predictive components related to the T cell activation in colorectal cancer mice. This study is of great significance for the development of novel anti-cancer drugs. It highlights the importance of network pharmacology-based approaches in studying complex traditional Chinese medicine formulations