Gastric cancer is one of the most frequent malignancies worldwide. Despite improvements in diagnosis and therapy, the overall prognosis remains poor. In the last decade, several anti-angiogenic drugs ...for cancer treatment have been approved and lately also introduced to gastric cancer treatment. While the initial trials focused only on unresectable or metastatic cancer, anti-angiogenic treatment is now also investigated in the perioperative and neoadjuvant setting. In this review, an overview of the role of angiogenesis and angiogenic factors in gastric cancer as well as anti-angiogenic treatment of gastric cancer is provided. Findings from in vitro and animal studies are summarized and put in a context with translational data on angiogenesis in gastric cancer. The most important angiogenic factors and their effect in gastric cancer are highlighted and clinical trials including anti-angiogenic drugs are discussed. Finally, an outlook of biomarkers for predicting response to anti-angiogenic treatment is presented, the ongoing trials on this topic are discussed and current challenges of anti-angiogenic therapy are outlined.
The gastrointestinal tract is abundantly colonized by microbes, yet the translocation of oral species to the intestine is considered a rare aberrant event, and a hallmark of disease. By studying ...salivary and fecal microbial strain populations of 310 species in 470 individuals from five countries, we found that transmission to, and subsequent colonization of, the large intestine by oral microbes is common and extensive among healthy individuals. We found evidence for a vast majority of oral species to be transferable, with increased levels of transmission in colorectal cancer and rheumatoid arthritis patients and, more generally, for species described as opportunistic pathogens. This establishes the oral cavity as an endogenous reservoir for gut microbial strains, and oral-fecal transmission as an important process that shapes the gastrointestinal microbiome in health and disease.
Ribosomal RNA profiling has become crucial to studying microbial communities, but meaningful taxonomic analysis and inter-comparison of such data are still hampered by technical limitations, ...between-study design variability and inconsistencies between taxonomies used.
Here we present MAPseq, a framework for reference-based rRNA sequence analysis that is up to 30% more accurate (F½ score) and up to one hundred times faster than existing solutions, providing in a single run multiple taxonomy classifications and hierarchical operational taxonomic unit mappings, for rRNA sequences in both amplicon and shotgun sequencing strategies, and for datasets of virtually any size.
Source code and binaries are freely available at https://github.com/jfmrod/mapseq.
mering@imls.uzh.ch.
Supplementary data are available at Bioinformatics online.
Water electrolysis is a key technology for future energy systems intended for the storage of fluctuating renewables and green industrial product upgrading. Under acidic electrolysis conditions, the ...oxygen evolution reaction (OER) predominantly causes the overpotential loss, which makes the elucidation of OER kinetics a task of key importance for future catalyst development. Herein, we design a methodology based on vapor-fed polymer electrolyte water electrolysis to fully characterize OER kinetics in the real environment of solid electrolytes and realize the controlled benchmarking of catalysts in the absence of gas passivation commonly observed in liquid-electrolyte half-cell configurations. Vapor-fed cells, allowing for distinct manipulation of water activity, sustain the essential degree of freedom to resolve and determine all four essential kinetic parameters. Thus, this work provides valuable insights into the OER mechanism, isolates the rate-determining step, and experimentally determines the reaction order of the state-of-the-art OER catalyst IrO
2
/TiO
2
with respect to water. Through the combination of gas and liquid fed kinetic analysis, we elucidate the important missing link for formulating the generic governing relation for the OER overpotential and thereby providing a method for benchmarking of catalyst activities under technically representative conditions.
The reaction order of water and the electro-kinetic parameters are determined for the oxygen evolution reaction on iridium oxide.
In recent years, the oxygen evolution reaction (OER) has attracted increased research interest due to its crucial role in electrochemical energy conversion devices for renewable energy applications. ...The vast majority of OER catalyst materials investigated are metal oxides of various compositions. The experimental results obtained on such materials strongly suggest the existence of a fundamental and universal correlation between the oxygen evolution activity and the corrosion of metal oxides. This corrosion manifests itself in structural changes and/or dissolution of the material. We prove from basic thermodynamic considerations that any metal oxide must become unstable under oxygen evolution conditions irrespective of the pH value. The reason is the thermodynamic instability of the oxygen anion in the metal oxide lattice. Our findings explain many of the experimentally observed corrosion phenomena on different metal oxide OER catalysts.
Biological soil crusts (BSCs) provide important ecosystem services in dryland regions, including erosion control and contribution to nitrogen and CO₂ fixation. As soil microorganisms are still rarely ...studied within the context of biodiversity planning, we describe, as a contribution to the Soil Crust International project, an approach that addresses this gap in biodiversity assessments. The purpose of the present study was a characterization of prokaryotic communities of BSCs formed by two species of lichenized fungi, Psora decipiens and Toninia sedifolia, in relation to surrounding BSCs and the below-crust soil layer from Tabernas basin (Almería, Spain). Microbial community profiles were determined using 454 pyrosequencing targeting the V4 hypervariable region of the bacterial and archaeal 16S rRNA gene. The majority of the 65,497 sequences obtained belonged to Proteobacteria (mainly Alphaproteobacteria), Actinobacteria, Bacteroidetes and Cyanobacteria. Cyanobacteria were more abundant at the soil surface but rare in below-crust soils, whilst below-crust soils harbored significantly more Acidobacteria, Verrucomicrobia, Gemmatimonadetes, Planctomycetes and Armatimonadetes. Additionally, terricolous lichens were investigated using fluorescence in situ hybridization in conjunction with confocal laser scanning microscopy, the objective being to illustrate bacterial niches in BSC-forming lichens. Bacteria were mainly present at the upper cortex of the squamules and attachment organs. Our findings indicate that the composition of soil prokaryotes varies at a small scale not only in adjacent soil layers but also in BSC-forming lichen species. Furthermore, bacteria were shown to be attached to fungal structures, probably representing a case of fungal-bacterial interaction.
A current challenge faced in water electrolysis is the development of structure–activity relationships for understanding and improving IrOx-based catalysts for the oxygen evolution reaction (OER). We ...report a simple and scalable modified Adams fusion method for preparing highly OER active, chlorine–free iridium oxide nanoparticles of various size and shape. The applied approach allows for the effects of particle size, morphology, and the nature of the surface species on the OER activity of IrO2 to be investigated. Iridium oxide synthesized at 350 °C from Ir(acac)3, consisting of 1.7 ± 0.4 nm particles with a specific surface area of 150 m2 g–1, shows the highest OER activity (E = 1.499 ± 0.003 V at 10 A gox –1). Operando X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS) studies indicate the presence of iridium hydroxo (Ir–OH) surface species, which are strongly linked to the OER activity. Preparation of larger IrO2 particles using higher temperatures results in a change of the particle morphology from spherical to rod-shaped particles. A decrease of the intrinsic OER activity was associated with the predominant termination of the rod-shape particles by highly ordered (110) facets in addition to limited diffusion within mesoporous features.
Operational Taxonomic Units (OTUs), usually defined as clusters of similar 16S/18S rRNA sequences, are the most widely used basic diversity units in large-scale characterizations of microbial ...communities. However, it remains unclear how well the various proposed OTU clustering algorithms approximate 'true' microbial taxa. Here, we explore the ecological consistency of OTUs--based on the assumption that, like true microbial taxa, they should show measurable habitat preferences (niche conservatism). In a global and comprehensive survey of available microbial sequence data, we systematically parse sequence annotations to obtain broad ecological descriptions of sampling sites. Based on these, we observe that sequence-based microbial OTUs generally show high levels of ecological consistency. However, different OTU clustering methods result in marked differences in the strength of this signal. Assuming that ecological consistency can serve as an objective external benchmark for cluster quality, we conclude that hierarchical complete linkage clustering, which provided the most ecologically consistent partitions, should be the default choice for OTU clustering. To our knowledge, this is the first approach to assess cluster quality using an external, biologically meaningful parameter as a benchmark, on a global scale.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Microorganisms play a role in the progression of various cancers. In this issue of Cancer Cell, Ghaddar et al. traced bacteria in pancreatic tumors at single-cell resolution and associated their ...intracellular presence with cell-type-specific transcriptional shifts, with links to clinical prognosis.
Microorganisms play a role in the progression of various cancers. In this issue of Cancer Cell, Ghaddar et al. traced bacteria in pancreatic tumors at single-cell resolution and associated their intracellular presence with cell-type-specific transcriptional shifts, with links to clinical prognosis.
We evaluate the low-temperature conductance of a weakly interacting one-dimensional helical liquid without axial spin symmetry. The lack of that symmetry allows for inelastic backscattering of a ...single electron, accompanied by forward scattering of another. This joint effect of weak interactions and potential scattering off impurities results in a temperature-dependent deviation from the quantized conductance, δG ∝ T4. In addition, δG is sensitive to the position of the Fermi level. We determine numerically the parameters entering our generic model for the Bernevig-Hughes-Zhang Hamiltonian of a HgTe/CdTe quantum well in the presence of Rashba spin-orbit coupling.
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