Late Quaternary aggradation and incision in the headwaters of the Yangtze River, eastern Tibetan Plateau, China

River aggradation or incision at different spatial-temporal scales are governed by tectonics, climate change, and surface processes which all adjust the ratio of sediment load to transport capacity of a channel. But how the river responds to differential tectonic and extreme climate events in a catchment is still poorly understood. Here, we address this issue by reconstructing the distribution, ages, and sedimentary process of fluvial terraces in a tectonically active area and monsoonal environment in the headwaters of the Yangtze River in the eastern Tibetan Plateau, China. Field observations, topographic analyses, and optically stimulated luminescence dating reveal a remarkable fluvial aggradation, followed by terrace formations at elevations of 55-62 m (T7), 42-46 m (T6), 38 m (T5), 22-36 m (T4), 18 m (T3), 12-16 m (T2), and 2-6 m (T1) above the present floodplain. Gravelly fluvial accumulation more than 62 m thick has been dated prior to 24-19 ka. It is regarded as a response to cold climate during the last glacial maximum. Subsequently, the strong monsoon precipitation contributed to cycles of rapid incision and lateral erosion, expressed as cut-in-fill terraces. The correlation of terraces suggests that specific tectonic activity controls the spatial scale and geomorphic characteristics of the terraces, while climate fluctuations determine the valley filling, river incision and terrace formation. Debris and colluvial sediments are frequently interbedded in fluvial sediment sequences, illustrating the episodic, short-timescale blocking of the channel ca. 20 ka. This indicates the potential impact of extreme events on geomorphic evolution in rugged terrain

Transport of Pacific water into the Canada Basin and the formation of the Chukchi Slope Current

Author Posting. © American Geophysical Union, 2018. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 123 (2018): 7453-7471, doi:10.1029/2018JC013825.A high‐resolution regional ocean model together with moored hydrographic and velocity measurements is used to identify the pathways and mechanisms by which Pacific water, modified over the Chukchi shelf, crosses the shelf break into the Canada Basin. Most of the Pacific water flowing into the Arctic Ocean through Bering Strait enters the Canada Basin through Barrow Canyon. Strong advection allows the water to cross the shelf break and exit the shelf. Wind forcing plays little role in this process. Some of the outflowing water from Barrow Canyon flows to the east into the Beaufort Sea; however, approximately 0.4 to 0.5 Sv turns to the west forming the newly identified Chukchi Slope Current. This transport occurs at all times of year, channeling both summer and winter waters from the shelf to the Canada Basin. The model indicates that approximately 75% of this water was exposed to the mixed layer within the Chukchi Sea, while the remaining 25% was able to cross the shelf during the stratified summer before convection commences in late fall. We view the Ό(0.5) Sv of the Chukchi Slope Current as replacing Beaufort Gyre water that would have come from the east in the absence of the cross-topography flow in Barrow Canyon. The weak eastward flow on the Beaufort slope is also consistent with the local disruption of the Beaufort Gyre by the Barrow Canyon outflow.Bureau of Ocean and Energy Management Grant Number: M12AC00008; DOC | National Oceanic and Atmospheric Administration (NOAA) Grant Number: NA16OAR4310248; National Science Foundation (NSF) Grant Numbers: PLR-1415489, OCE-15331702019-04-2

Human adenovirus type 7 subunit vaccine induces dendritic cell maturation through the TLR4/NF-κB pathway is highly immunogenic

IntroductionHuman adenovirus type 7 (HAdv-7) infection is the main cause of upper respiratory tract infection, bronchitis and pneumonia in children. At present, there are no anti- adenovirus drugs or preventive vaccines in the market. Therefore, it is necessary to develop a safe and effective anti-adenovirus type 7 vaccine.MethodsIn this study, In this study, we used the baculovirus-insect cell expression system to design a recombinant subunit vaccine expressing adenovirus type 7 hexon protein (rBV-hexon) to induce high-level humoral and cellular immune responses. To evaluate the effectiveness of the vaccine, we first detected the expression of molecular markers on the surface of antigen presenting cells and the secretion of proinflammatory cytokines in vitro. We then measured the levels of neutralizing antibodies and T cell activation in vivo.ResultsThe results showed that the rBV-hexon recombinant subunit vaccine could promote DC maturation and improve its antigen uptake capability, including the TLR4/NF-κB pathway which upregulated the expression of MHCI, CD80, CD86 and cytokines. The vaccine also triggered a strong neutralizing antibody and cellular immune response, and activated T lymphocytes.DiscussionTherefore, the recombinant subunit vaccine rBV-hexon promoted promotes humoral and cellular immune responses, thereby has the potential to become a vaccine against HAdv-7

Interplay between Lefty and Nodal signaling is essential for the organizer and axial formation in amphioxus embryos

Abstract(#br)The organizer is an essential signaling center required for axial formation during vertebrate embryonic development. In the basal chordate amphioxus, the dorsal blastopore lip of the gastrula has been proposed to be homologous to the vertebrate organizer. Lefty is one of the first genes to be expressed in the organizer. The present results show that Lefty overexpression abolishes the organizer; the embryos were severely ventralized and posteriorized, and failed to develop anterior and dorsal structures. In Lefty knockouts the organizer is enlarged, and anterior and dorsal structures are expanded. Different from Lefty morphants in vertebrates, amphioxus Lefty mutants also exhibited left-right defects. Inhibition of Nodal with SB505124 partially rescued the effects of Lefty loss-of-function on morphology. In addition, while SB505124 treatment blocked Lefty expression in the cleavage stages of amphioxus embryos, activation of Nodal signaling with Activin protein induced ectopic Lefty expression at these stages. These results show that the interplay between Lefty and Nodal signaling plays an essential role in the specification of the amphioxus organizer and axes

Effects of Boric Acid Gel on Vaginal Candida albicans Infections and the Local Immune System in Mice

The objective was to determine the effect of 5% boric acid gel on vaginal Candida albicans (CA) infections in mice and its effect on the local immune system (i.e., Th1, Th2, and Th17). Female mice were divided into four groups, with 10 mice in each group. Mycelial suspensions were administered into the vaginal lumen close to the cervix in groups B, F, and M. Mice in group B were given boric acid gel, and group F was treated with fluconazole gel for 30 min every 12 h. Group M was treated with sterile water, and group N was not given treatment. After the seventh day of treatment, each group was observed with the naked eye, and vaginal lavage fluid and vaginal tissue were collected. Expression levels of cytokines were measured using enzyme-linked immunosorbent assays (ELISA) and immunohistochemistry. Periodic acid Schiff (PAS) staining was used to measure the fungi in vaginal tissues. There were no significant changes in group M. In groups B and F, there was less vaginal injury and less exudate, with group B doing better than group F. The numbers of CA colonies were higher in groups B, F, and M than in group N (P < 0.01). There was less vaginal colonization of CA in group B than in group F (P < 0.01). After the seventh day of treatment, levels of IFN-γ, IL-17, IL-6, TGF-β, IL-4, and IL-10 were significantly greater in groups B, F, and M than in group N (P < 0.001); levels of IFN-γ, IL-17, IL-6, and TGF-β in groups B and F were higher than those of group M (P < 0.01), while IL-4 and IL-10 levels were significantly lower (P < 0.001). The trends of cytokine increases and decreases were more significant in group B than in group F (P < 0.05). Immunohistochemical results were similar to ELISA results. PAS staining revealed that boric acid inhibited hyphal reproduction. The boric acid significantly reduced the symptoms associated with CA vaginal infection. It inhibited the CA growth, prevented vaginal lesions, promoted the secretion of Th1 and Th17 cytokines, and reduced Th2 cytokines

Study on cutting performance of SiCp/Al composite using textured YG8 carbide tool

Precision machining of SiCp/Al composites is a challenge due to the existence of reinforcement phase in this material. This work focuses on the study of the textured tools’ cutting performance on SiCp/Al composite, as well as the comparison with non-textured tools. The results show that the micro-pit textured tool can reduce the cutting force by 5–13% and cutting length by 9–39%. Compared with non-textured tools, the cutting stability of the micro-pit textured tools is better. It is found that the surface roughness is the smallest (0.4 μm) when the texture spacing is 100 μm, and the residual stress can be minimized to around 15 MPa in the case of texture spacing 80 μm. In addition, the SiC particles with size of around 2–12 μm in the SiCp/Al composite may play a supporting role between the texture and the chips, which results in three-body friction, thereby reducing tool wear, sticking, and secondary cutting phenomenon. At the same time, some SiC particles enter into the micro-pit texture, so that the number of residual particles on the surface is reduced and the friction between the tool and the surface then decreases, which improves the surface roughness, and reduces the surface residual stress.TU Berlin, Open-Access-Mittel - 202

Research on the micro-hole texture forming of PCD tool surface

Based on the research on the forming mechanism of textured PCD tool surface, the nanosecond laser is used to study the influence of laser machining parameters on the size and topography of PCD tool surface micro texture. The micro-hole texture is prepared on the surface of the PCD tool, and a single factor experiment is designed to study the influence of laser power, pulse frequency and defocusing amount on the micro-hole texture. The results show that, the micro-hole diameter increases gradually with the laser power, but decreases with the pulse frequency; the overall micro-hole diameter tends to increase with the defocus. The pulse frequency has the greatest impact on the micro-hole diameter, followed by the defocus amount, and finally the laser power. The influence of different parameters on the surface recast layer is also completely different. As a result, the surface and laser power are the main factors that affect the surface recast layer

Epidemic clones, oceanic gene pools and eco-LD in the free living marine pathogen Vibrio parahaemolyticus

We investigated global patterns of variation in 157 whole genome sequences of Vibrio parahaemolyticus, a free-living and seafood associated marine bacterium. Pandemic clones, responsible for recent outbreaks of gastroenteritis in humans have spread globally. However, there are oceanic gene pools, one located in the oceans surrounding Asia and another in the Mexican Gulf. Frequent recombination means that most isolates have acquired the genetic profile of their current location. We investigated the genetic structure in the Asian gene pool by calculating the effective population size in two different ways. Under standard neutral models, the two estimates should give similar answers but we found a thirty fold difference. We propose that this discrepancy is caused by the subdivision of the species into a hundred or more ecotypes which are maintained stably in the population. To investigate the genetic factors involved, we used 51 unrelated isolates to conduct a genome-wide scan for epistatically interacting loci. We found a single example of strong epistasis between distant genome regions. A majority of strains had a type VI secretion system associated with bacterial killing. The remaining strains had genes associated with biofilm formation and regulated by c-di-GMP signaling. All strains had one or other of the two systems and none of isolate had complete complements of both systems, although several strains had remnants. Further top-down analysis of patterns of linkage disequilibrium within frequently recombining species will allow a detailed understanding of how selection acts to structure the pattern of variation within natural bacterial populations

Complete genome sequence and comparative analysis of a Vibrio vulnificus strain isolated from a clinical patient

Vibrio vulnificus is an opportunistic, global pathogen that naturally inhabits sea water and is responsible for most vibriosis-related deaths. We investigated the genetic characteristics of V. vulnificus isolated from the clinical blood culture specimen of a patient with hepatitis B virus cirrhosis in 2018 (named as V. vulnificus VV2018) by whole genome sequencing (WGS). VV2018 belonged to a novel sequencing type 620 (ST620) and comprised two circular chromosomes, containing 4,389 potential coding sequences (CDSs) and 152 RNA genes. The phylogenetic tree of single nucleotide polymorphisms (SNPs) using 26 representative genomes revealed that VV2108 grouped with two other V. vulnificus strains isolated from humans. The pan-genome of V. vulnificus was constructed using 26 representative genomes to elucidate their genetic diversity, evolutionary characteristics, and virulence and antibiotic resistance profiles. The pan-genome analysis revealed that VV2018 shared a total of 3,016 core genes (≥99% presence), including 115 core virulence factors (VFs) and 5 core antibiotic resistance-related genes, and 309 soft core genes (≥95 and <99% presence) with 25 other V. vulnificus strains. The varG gene might account for the cefazolin resistance, and comparative analysis of the genetic context of varG revealed that two genes upstream and downstream of varG were conserved. The glycosylation (pgl) like genes were found in VV2018 compared with Pgl-related proteins in Neisseria that might affect the adherence of the strain in hosts. The comparative analysis of VV2018 would contribute to a better understanding of the virulence and antibiotic resistance profiles of V. vulnificus. Meanwhile much work remains to be done to better understand the function of pgl-like genes in V. vulnificus

Metagenomic Sequencing From Mosquitoes in China Reveals a Variety of Insect and Human Viruses

We collected 8,700 mosquitoes in three sites in China, which belonged to seven species. Their viromes were tested using metagenomic sequencing and bioinformatic analysis. The abundant viral sequences were detected and annotated belonging to more than 50 viral taxonomic families. The results were verified by PCR, followed by phylogenetic analysis. In the present study, we identified partial viral genes of dengue virus (DENV), a novel circovirus (CCV), densovirus (DNV), Japanese encephalitis virus (JEV), and Wuhan mosquito virus (WMV) in mosquitoes. Metagenomic analysis and PCR amplification revealed three DENV sequences, which were as homologous to the NS3 gene of DENV from Singapore isolated in 2005, with at least 91% nucleotide (nt) identity. Seven fragments of JEV encoding structural proteins were identified belonging to genotype I. They all shared high homology with structural protein genes of JEV isolated from Laos in 2009. The production of infectious virus particles of the newly isolated virus YunnanJEV2017-4 increased after passage from the BHK-21 cell line to the Vero cell line. Novel circovirus-related genes were identified and as being related to an unnamed gene of a mosquito circovirus (MCCV) sequence from the USA isolated in 2011, with at least 41% nt identity: this distant relationship suggests that the parent virus might belong to a novel circovirus genus. Additionally, numerous known viruses and some unknown viruses were also detected in mosquitoes from Yunnan province, China, which will be tested for propagation