868 research outputs found

    Dextral and sinistral Amphidromus inversus (Gastropoda: Pulmonata: Camaenidae) produce dextral sperm

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    Coiling direction in pulmonate gastropods is determined by a single gene via a maternal effect, which causes cytoskeletal dynamics in the early embryo of dextral gastropods to be the mirror image of the same in sinistral ones. We note that pulmonate gastropod spermatids also go through a helical twisting during their maturation. Moreover, we suspect that the coiling direction of the helical elements of the spermatozoa may affect their behaviour in the female reproductive tract, giving rise to the possibility that sperm chirality plays a role in the maintenance of whole-body chiral dimorphism in the tropical arboreal gastropod Amphidromus inversus (Müller, 1774). For these reasons, we investigated whether there is a relationship between a gastropod’s body chirality and the chirality of the spermatozoa it produces. We found that spermatozoa in A. inversus are always dextrally coiled, regardless of the coiling direction of the animal itself. However, a partial review of the literature on sperm morphology in the Pulmonata revealed that chiral dimorphism does exist in certain species, apparently without any relationship with the coiling direction of the body. Though our study shows that body and sperm chirality follows independent developmental pathways, it gives rise to several questions that may be relevant to the understanding of the chirality of spermatid ultrastructure and spermatozoan motility and sexual selection

    Technical Note: Latitude-time variations of atmospheric column-average dry air mole fractions of CO_2, CH_4 and N_2O

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    We present a comparison of an atmospheric general circulation model (AGCM)-based chemistry-transport model (ACTM) simulation with total column measurements of CO_2, CH_4 and N_2O from the Total Carbon Column Observing Network (TCCON). The model is able to capture observed trends, seasonal cycles and inter hemispheric gradients at most sampled locations for all three species. The model-observation agreements are best for CO_2, because the simulation uses fossil fuel inventories and an inverse model estimate of non-fossil fuel fluxes. The ACTM captures much of the observed seasonal variability in CO_2 and N_2O total columns (~81 % variance, R>0.9 between ACTM and TCCON for 19 out of 22 cases). These results suggest that the transport processes in troposphere and stratosphere are well represented in ACTM. Thus the poor correlation between simulated and observed CH4 total columns, particularly at tropical and extra-tropical sites, have been attributed to the uncertainties in surface emissions and loss by hydroxyl radicals. While the upward-looking total column measurements of CO_2 contains surface flux signals at various spatial and temporal scales, the N_2O measurements are strongly affected by the concentration variations in the upper troposphere and stratosphere

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Variations of tropospheric methane over Japan during 1988–2010

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    We present observations of CH4 concentrations from the lower to upper troposphere (LT and UT) over Japan during 1988–2010 based on aircraft measurements from the Tohoku University (TU). The analysis is aided by simulation results using an atmospheric chemistry transport model (i.e. ACTM). Tropospheric CH4 over Japan shows interannual and seasonal variations that are dependent on altitudes, primarily reflecting differences in air mass origins at different altitudes. The long-term trend and interannual variation of CH4 in the LT are consistent with previous reports of measurements at surface baseline stations in the northern hemisphere. However, those in the UT show slightly different features from those in the LT. In the UT, CH4 concentrations show a seasonal maximum in August due to efficient transport of air masses influenced by continental CH4 sources, while LT CH4 reaches its seasonal minimum during summer due to enhanced chemical loss. Vertical profiles of the CH4 concentrations also vary with season, reflecting the seasonal cycles at the respective altitudes. In summer, transport of CH4-rich air from Asian regions elevates UT CH4 levels, forming a uniform vertical profile above the mid-troposphere. On the other hand, CH4 decreases nearly monotonically with altitude in winter–spring. The ACTM simulations with different emission scenarios reproduce general features of the tropospheric CH4 variations over Japan. Tagged tracer simulations using the ACTM indicate substantial contributions of CH4 sources in South Asia and East Asia to the summertime high CH4 values observed in the UT. This suggests that our observations over Japan are highly sensitive to CH4 emission signals particularly from Asia

    Hepatocyte Growth Factor Increases Osteopontin Expression in Human Osteoblasts through PI3K, Akt, c-Src, and AP-1 Signaling Pathway

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    BACKGROUND: Hepatocyte growth factor (HGF) has been demonstrated to stimulate osteoblast proliferation and participated bone remodeling. Osteopontin (OPN) is a secreted phosphoglycoprotein that belongs to the SIBLING family and is present during bone mineralization. However, the effects of HGF on OPN expression in human osteoblasts are large unknown. METHODOLOGY/PRINCIPAL FINDINGS: Here we found that HGF induced OPN expression in human osteoblasts dose-dependently. HGF-mediated OPN production was attenuated by c-Met inhibitor and siRNA. Pretreatment of osteoblasts with PI3K inhibitor (Ly294002), Akt inhibitor, c-Src inhibitor (PP2), or AP-1 inhibitor (curcumin) blocked the potentiating action of HGF. Stimulation of osteoblasts with HGF enhanced PI3K, Akt, and c-Src activation. In addition, incubation of cells with HGF also increased c-Jun phosphorylation, AP-1-luciferase activity, and c-Jun binding to the AP-1 element on the OPN promoter. HGF-mediated AP-1-luciferase activity and c-Jun binding to the AP-1 element was reduced by c-Met inhibitor, Ly294002, Akt inhibitor, and PP2. CONCLUSIONS/SIGNIFICANCE: Our results suggest that the interaction between HGF and c-Met increases OPN expression in human osteoblasts via the PI3K, Akt, c-Src, c-Jun, and AP-1 signaling pathway

    Ethanolic extract of the natural product of Daun sirih (Piper betle) leaves may impede the effectiveness of the plasma jet contact style for acute wounds

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    Purpose: An investigation was carried out to determine the effect of an ethanolic extract of the natural product of Daun sirih or Piper betle leaves on the effectiveness of plasma jet treatment for cutaneous acute wound healing in a small animal model mimicking a clinical setting. Method: An atmospheric plasma jet using medical grade argon gas as a carrier gas was developed. The ethanolic extract of Piper betle leaf (EPB) was formulated. Optical emission spectroscopy and chemical methods were applied to evaluate the presence of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the gas phase and in aqueous and ethanolic media. Small animals were classified into 5 groups, namely, Control (C), Plasma jet (P), Ethanolic extract of Piper betle leaf (EPB), Plasma jet followed by EPB (P-EPB) and EPB followed by plasma jet (EPB-P). The contact and meander styles of plasma jet treatment for wounds were applied daily on acute wounds for 1 min, either alone or before or after EPB treatments. Visual evaluation of wounds was conducted for 14 days. Microscopic evaluation was conducted on days 7, 11 and 14. General staining, namely, haematoxylin-eosin and Azan staining, was conducted to evaluate neoepithelialisation and new collagen formation. Results: This research showed that wound healing in the P group was faster than that in the other groups, while that in groups containing EPB was the same as that in C. In the P group, the number of days to reach peak inflammation was the fewest. On day 7, neoepithelialisation and new collagen formation in P were significantly higher than those in other groups. Conclusion: Plasma jet treatment alone is able to promote inflammation, neoepithelialisation and new collagen formation to accelerate acute wound healing; however, its admixture with EPB may impede such effectiveness. Based on the characterization of the ROS and RNS results, the ethanol solvent may play a primary role in impeding its effectiveness

    Human Gastric Mucins Differently Regulate Helicobacter pylori Proliferation, Gene Expression and Interactions with Host Cells

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    Helicobacter pylori colonizes the mucus niche of the gastric mucosa and is a risk factor for gastritis, ulcers and cancer. The main components of the mucus layer are heavily glycosylated mucins, to which H. pylori can adhere. Mucin glycosylation differs between individuals and changes during disease. Here we have examined the H. pylori response to purified mucins from a range of tumor and normal human gastric tissue samples. Our results demonstrate that mucins from different individuals differ in how they modulate both proliferation and gene expression of H. pylori. The mucin effect on proliferation varied significantly between samples, and ranged from stimulatory to inhibitory, depending on the type of mucins and the ability of the mucins to bind to H. pylori. Tumor-derived mucins and mucins from the surface mucosa had potential to stimulate proliferation, while gland-derived mucins tended to inhibit proliferation and mucins from healthy uninfected individuals showed little effect. Artificial glycoconjugates containing H. pylori ligands also modulated H. pylori proliferation, albeit to a lesser degree than human mucins. Expression of genes important for the pathogenicity of H. pylori (babA, sabA, cagA, flaA and ureA) appeared co-regulated in response to mucins. The addition of mucins to co-cultures of H. pylori and gastric epithelial cells protected the viability of the cells and modulated the cytokine production in a manner that differed between individuals, was partially dependent of adhesion of H. pylori to the gastric cells, but also revealed that other mucin factors in addition to adhesion are important for H. pylori-induced host signaling. The combined data reveal host-specific effects on proliferation, gene expression and virulence of H. pylori due to the gastric mucin environment, demonstrating a dynamic interplay between the bacterium and its host

    When plasma jet is effective for chronic wound bacteria inactivation, is it also effective for wound healing?

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    Purpose: This investigation aimed to compare the effectiveness of two styles of plasma jet treatment (i.e., contact and non-contact styles) for two biological materials, namely, wound related bacteria and acute wounds. Method: An atmospheric plasma jet operated at a frequency of 18.32 kHz and high AC voltage with a peak-topeak voltage of 9.58 kV and a current of 55.2 mA was applied. Argon gas was used as the carries gas of plasma jet generation and was fixed at a flow rate of 1 standard liters per minute (slm).Two biological materials (i.e., wound related bacteria and acute wound) were applied as experimental objects. The sample groups were based on the two styles of plasma jet treatment: contact and non-contact styles. Microbial inhibition zone calculation and macroscopic and histological observations were also performed. Results: This investigation emphasized that the contact and non-contact styles of plasma jet treatment had significantly different effects for wounds and wound-related chronic bacteria. On the one hand, the contact style was visually attractive and more effective for inactivate bacteria. On the other hand, it caused negative effects, such as damaging normal tissue, significantly impeding wound healing and impeding the growing of new epithelial tissue. The non-contact style, however, was less effective at inactivating bacteria; however, it could accelerate wound healing. Conclusion: In the context of wound healing, the non-contact style of plasma jet treatment may be better than the contact style of plasma jet treatment
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