Summary
We explored the association between gut microbiota composition and bone mineral loss in Chinese elderly people by high-throughput 16S ribosomal RNA (rRNA) gene sequencing. Compared with ...controls, a smaller number of operational taxonomic units (OTUs), several taxa with altered abundance, and specific functional pathways were found in individuals with low-bone mineral density (BMD).
Introduction
Gut microbiota plays important roles in human health and associates with a number of diseases. However, few studies explored its association with bone mineral loss in human.
Methods
We collected 102 fecal samples from each eligible individual belonging to low-BMD and control groups for high-throughput 16S rRNA gene sequencing.
Results
The low-BMD individuals had a smaller number of OTUs and bacterial taxa at each level. At the phylum level, Bacteroidetes were more abundant in the low-BMD group; Firmicutes were enriched in the control group; Firmicutes and Actinobacteria positively correlated and Bacteroidetes negatively correlated with the BMD and T-score in all subjects. At the family level, the abundance of Lachnospiraceae in low-BMD individuals reduced and positively correlated with BMD and T-score; meanwhile, BMD increased with increasing Bifidobacteriaceae. At the genus level, low-BMD individuals had decreased proportions of
Roseburia
compared with control ones (
P
< 0.05).
Roseburia
,
Bifidobacterium
, and
Lactobacillus
positively correlated with BMD and T-score. Furthermore, BMD increased with rising abundance of
Bifidobacterium
. Functional prediction revealed that 93 metabolic pathways significantly differed between the two groups (FDR-corrected
P
< 0.05). Most pathways, especially pathways related to LPS biosynthesis, were more abundant in low-BMD individuals than in control ones.
Conclusions
Several taxa with altered abundance and specific functional pathways were discovered in low-BMD individuals. Our findings provide novel epidemiologic evidence to elucidate the underlying microbiota-relevant mechanism in bone mineral loss and osteoporosis.
We quantify the bulk topographic characteristics of the Tibet‐Qinghai plateau with specific focus on three representative regions: northern, central, and southeastern Tibet. Quantitative landscape ...information is extracted from Shuttle Radar Topography Mission digital elevation models. We find that the morphology of the Tibetan plateau is nonuniform with systematic regional differences. The northern and central parts of the plateau are characterized by what we suggest to call “positive topography,” i.e., a topography in which elevation is positively correlated with relief and mean slope. A major change from the internally drained central part of Tibet to the externally drained part of eastern Tibet is accompanied by a transition from low to high relief and from positive to “negative topography,” i.e., a topography where there is an inverse or negative correlation between elevation and relief and between elevation and mean slope. Relief in eastern Tibet is largest along rivers as they cross an ancient, eroded plateau margin at high angle to the major strike‐slip faults, the Yalong‐Yulong thrust belt, implying strong structural control of regional topography. We propose that the evolution of river systems and drainage efficiency, the ability of rivers to transport sediments out of the orogen, coupled with tectonic uplift, is the simplest mechanism to explain systematic regional differences in Tibetan landscapes. Basin filling due to inefficient drainage played a major role in smoothing out the tectonically generated structural relief. This mode of smoothing started concurrently with tectonic construction of the relief, as most clearly illustrated today in the Qilian Shan‐Qaidam region of the northeastern plateau. In the interior of Tibet, further “passive” filling, due to internal drainage only, continued to smooth the local relief millions of years after the cessation of major phases of surface uplift due to crustal shortening. Thus, diachronous beveling at high elevation produced the low‐relief surface of the high plateau. In southeast Tibet, headward retreat of external drainages brought back “in” the global ocean base level, first disrupting then interrupting the relief‐reduction process. It produced a transitional topography by dissecting the “old” remnant plateau surface, which introduced younger and steeper incision of this hitherto preserved high base level. This provides a unifying mechanism for the formation of the low‐relief plateau interior, and for the origin of the high‐elevation, low‐relief relict surface in southeastern Tibet. Our analysis brings forth the importance of surface processes, in particular drainage efficiency, in shaping plateau morphology and landscape relief. Such key processes appear to have been mostly ignored in numerical models of plateau deformation. Our results also cast doubt on and provide a more realistic alternative to the fashionable contention that a continuous preuplift, low‐relief surface first formed at low elevation, extending all the way to the South China Sea shore, before being warped upward in the late Miocene‐Pliocene by lower crustal channel flow.
Antibiotic resistance genes (ARGs), as emerging environmental contaminants, have become a threat to human health. Recent studies have demonstrated that the effluent from wastewater treatment plants ...is a significant point source of ARGs released into the environment. In this study, we investigated the effectiveness of coagulation technology in the removal of ARGs from treated wastewater. Specifically, we measured the removal of five ARGs (two sulfonamide resistance genes, sulI and sulII, and three tetracycline resistance genes, tetO, tetW and tetQ) and the class 1 integron intI1 gene via the application of two coagulants: FeCl3 and polyferric chloride (PFC). Moreover, the removal of dissolved organic carbon (DOC), NH3N and total phosphorus (TP) in the coagulation process was investigated. The coagulation process effectively removed ARGs from the effluent with 0.5-log to 3.1-log reductions. Significant removal correlations were observed between dissolved NH3N and DOC, intI1 and sulI, sulII and tetO, sulII and tetW, and tetO and tetW, implying that the co-removal of DOC, dissolved NH3N, the intI1 gene and different ARGs played an important role in ARG loss during coagulation with Fe-based coagulants. These results indicate that coagulation may play a promising role in ARG reduction in wastewater treatment plants.
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•Coagulation effectively removed ARGs from effluent with 0.5-log to 3.1-log reduction.•Removal between sulI and intI1, sulII/tetO and tetW have significant correlations.•Fe species may influence ARG removal in coagulation process.•Coagulation is an effective technique for ARG removal from WWTP effluent.
Green upconversion emission from hexagonal‐phase NaYF4:Yb, Er3+ phosphors can be directly observed with the naked eye. Powders with controlled size and morphology can be synthesized in ethanol and ...show a minimal decrease in luminescence intensity after 24 h (see Figure). The intense upconversion emission suggests good crystallinity of the materials, which may be used in biological labeling.
In this work, the antibacterial activity and mechanism of chloroform fraction obtained from aqueous extract of mugwort leaves against Staphylococcus aureus were investigated. The extract showed ...obvious antibacterial activity against S. aureus which the minimum inhibitory concentration and minimum bactericidal concentration were determined to be 3·0 and 6·0 mg ml−1 respectively. The mechanism study suggested that the extract could destroy the integrity of the S. aureus cell walls and increase the permeability of cell membrane in a certain concentration, but it could not kill S. aureus in a short time. Instead, the extract could make bacteria in a state of apoptosis for a long time, interfere with the normal physiological metabolism of bacteria, and eventually make bacteria die, which was confirm by scanning electronic microscope.
Significance and Impact of the Study: Since ancient times, Mugwort (Artemisia argyi L.) has been widely used as a traditional medicine for many diseases including bacterial infectious diseases; therefore, it plays a very important role in protecting people’s health. Previous studies have proved that the essential oil of mugwort has antibacterial activity; however, the antibacterial activity of the non‐volatile components of it is still unknown. In this work, the antibacterial activity and mechanism of aqueous extract of mugwort leaves were investigated for the first time. The results obtained from this study provide a scientific basis for revealing the antibacterial activity of the non‐volatile components of mugwort, and lays a foundation for further development and utilization of mugwort.
β-Catenin is a potent oncogenic protein in colorectal cancer (CRC), but the targets and regulation of this important signalling molecule are not completely understood. Hypoxia is a prominent feature ...of solid tumours that contributes to cancer progression.
Here, we analysed the regulation between Nur77 and β-catenin under hypoxic conditions. Cell proliferation, migration, and invasion assays were performed to assess functional consequences.
We showed that hypoxia stimulated co-upregulation of β-catenin and Nur77 in a number of human CRC cell lines. Interestingly, expression of β-catenin and Nur77 by hypoxia formed a mutual feedback regulation circuits that conferred aggressive growth of CRC. Overexpression of β-catenin increased Nur77 transcription through hypoxia-inducible factor-1α rather than T-cell factor. Nur77-mediated activation of β-catenin by hypoxia was independent of both DNA binding and transactivation. Further, we showed that hypoxic activation of β-catenin was independent of the classical adenomatous polyposis coli and p53 pathways, but stimulated by phosphatidylinositol 3-kinase/Akt in a Nur77-dependent manner. Under hypoxic conditions, enhanced β-catenin and Nur77 expression synergistically stimulated CRC cell migration, invasion, and epithelial-mesenchymal transition.
These findings provide a novel molecular mechanism for hypoxic CRCs that may contribute to tumour progression, and its targeting may represent an effective therapeutic avenue.
Using first-principles transport calculations, we predict that the anisotropic magnetoresistance (AMR) of single-crystal CoxFe1−x alloys is strongly dependent on the current orientation and alloy ...concentration. An intrinsic mechanism for AMR is found to arise from the band crossing due to magnetization-dependent symmetry protection. These special k points can be shifted towards or away from the Fermi energy by varying the alloy composition and hence the exchange splitting, thus allowing AMR tunability. The prediction is confirmed by delicate transport measurements, which further reveal a reciprocal relationship of the longitudinal and transverse resistivities along different crystal axes.
One of the greatest challenges in the application of organic phase change materials (PCMs) is to increase their thermal conductivity while maintaining high phase change enthalpy. 1-Tetradecanol/Ag ...nanowires composite PCM containing 62.73 wt% (about 11.8 vol%) of Ag nanowires showed remarkably high thermal conductivity (1.46 W m
−1
K
−1
) and reasonably high phase change enthalpy (76.5 J g
−1
). This behavior was attributed to the high aspect ratio of Ag nanowires, few thermal conduct interfaces, and high interface thermal conductivity of Ag nanowires in the composite PCM. These results indicated that Ag nanowires might be strong candidates for thermal conductivity enhancement of organic PCMs.
With more Au alloying with Pd, hydrogen atoms adsorption on Pd-Au alloy surfaces would be gradually weakened. Due to this change in H adsorption strength, the dissociated hydrogen atoms from formic ...acid are easier to combine as hydrogen molecules on Pd-Au alloy nanoclusters than that on pure Pd clusters.
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•The formic acid molecule can be decomposed on both pure Pd and Pd-Au alloy catalysts.•Hydrogen atoms are difficult to combine as hydrogen molecules on pure Pd catalysts.•The hydrogen production becomes a reaction process with large probability on Pd-Au alloy catalysts.
Recently, it has been reported that the hydrogen production rate of formic acid decomposition can be significantly increased using Pd-Au binary alloy nano-catalysts Wang et al. J. Mater. Chem. A 1 (2013) 12721–12725. To explain the reaction mechanism of this alloy catalysis method, formic acid decomposition reactions on pure Pd and Pd-Au alloy nanoclusters are studied via density functional theory simulations. The simulation results indicate that the addition of inert element Au would not influence formic acid decomposition on Pd surface sites of Pd-Au alloy nanoclusters. On the other hand, the existence of Au surface sites brings relative weak hydrogen atom adsorption. On Pd-Au alloy nanoclusters, the dissociated hydrogen atoms from formic acid are easier to combine as hydrogen molecules than that on pure Pd clusters. Via the synergetic effect between Pd and Au, both formic acid decomposition and hydrogen production are events with large probability, which eventually results in high hydrogen production rate.
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