Search

Bone regeneration is a sophisticated, precisely controlled physiological process. In addition to bone metabolism balance under normal conditions, bone regeneration occurs also in bone repair process following bone damage or diseases. Clinically, treatment of critical bone defects typically requires the use of a series intervention technologies for bone regeneration, including transplantation, administration of growth factors, distraction osteogenesis and others. Exosome is a newly emerging research field, and has been used in many medical indications with notable therapeutic outcomes. However, due to the sophisticated chemical compositions of exosomes, composing of lipid bilayers encapsulating a number of protein and nucleic acid molecules, the mechanism of action studies, manufacturing process and clinical applications are largely impeded. Specifically, in the applications of exosome-mediated therapy for bone defects, many fundamental scientific questions remain to be elucidated, such as how exosomes enter acceptor cells and exert their functions. This review will introduce therapeutic approaches for bone defects and basic concepts of exosomes, discuss the molecular mechanisms of stem cell -derived exosome for treating bone defects, propose the roles of emerging biotechnologies such as CRISPR-Cas genome editing in studying the exosome treatment of bone defects and finally forecast the trend of stem cell-derived exosomes for treating bone defects.

We present the cosmological implications from final measurements of clustering using galaxies, quasars, and Lyα forests from the completed Sloan Digital Sky Survey (SDSS) lineage of experiments in large-scale structure. These experiments, composed of data from SDSS, SDSS-II, BOSS, and eBOSS, offer independent measurements of baryon acoustic oscillation (BAO) measurements of angular-diameter distances and Hubble distances relative to the sound horizon, rd, from eight different samples and six measurements of the growth rate parameter, fσ8, from redshift-space distortions (RSD). This composite sample is the most constraining of its kind and allows us to perform a comprehensive assessment of the cosmological model after two decades of dedicated spectroscopic observation. We show that the BAO data alone are able to rule out dark-energy-free models at more than eight standard deviations in an extension to the flat, ΛCDM model that allows for curvature. When combined with Planck Cosmic Microwave Background (CMB) measurements of temperature and polarization, under the same model, the BAO data provide nearly an order of magnitude improvement on curvature constraints relative to primary CMB constraints alone. Independent of distance measurements, the SDSS RSD data complement weak lensing measurements from the Dark Energy Survey (DES) in demonstrating a preference for a flat ΛCDM cosmological model when combined with Planck measurements. The combined BAO and RSD measurements indicate σ8=0.85±0.03, implying a growth rate that is consistent with predictions from Planck temperature and polarization data and with General Relativity. When combining the results of SDSS BAO and RSD, Planck, Pantheon Type Ia supernovae (SNe Ia), and DES weak lensing and clustering measurements, all multiple-parameter extensions remain consistent with a ΛCDM model. Regardless of cosmological model, the precision on each of the three parameters, ωΛ, H0, and σ8, remains at roughly 1%, showing changes of less than 0.6% in the central values between models. In a model that allows for free curvature and a time-evolving equation of state for dark energy, the combined samples produce a constraint ωk=-0.0022±0.0022. The dark energy constraints lead to w0=-0.909±0.081 and wa=-0.49-0.30+0.35, corresponding to an equation of state of wp=-1.018±0.032 at a pivot redshift zp=0.29 and a Dark Energy Task Force Figure of Merit of 94. The inverse distance ladder measurement under this model yields H0=68.18±0.79 km s-1 Mpc-1, remaining in tension with several direct determination methods; the BAO data allow Hubble constant estimates that are robust against the assumption of the cosmological model. In addition, the BAO data allow estimates of H0 that are independent of the CMB data, with similar central values and precision under a ΛCDM model. Our most constraining combination of data gives the upper limit on the sum of neutrino masses at mν

Abstract We analyse the large-scale clustering in Fourier space of emission line galaxies (ELG) from the Data Release 16 of the Sloan Digital Sky Survey IV extended Baryon Oscillation Spectroscopic Survey. The ELG sample contains 173,736 galaxies covering 1,170 square degrees in the redshift range 0.6 < z < 1.1. We perform a BAO measurement from the post-reconstruction power spectrum monopole, and study redshift space distortions (RSD) in the first three even multipoles. Photometric variations yield fluctuations of both the angular and radial survey selection functions. Those are directly inferred from data, imposing integral constraints which we model consistently. The full data set has only a weak preference for a BAO feature (1.4σ). At the effective redshift zeff = 0.845 we measure $D_{\rm V}(z_{\rm eff})/r_{\rm drag} = 18.33_{-0.62}^{+0.57}$, with DV the volume-averaged distance and rdrag the comoving sound horizon at the drag epoch. In combination with the RSD measurement, at zeff = 0.85 we find $f\sigma _8(z_{\rm eff}) = 0.289_{-0.096}^{+0.085}$, with f the growth rate of structure and σ8 the normalisation of the linear power spectrum, $D_{\rm H}(z_{\rm eff})/r_{\rm drag} = 20.0_{-2.2}^{+2.4}$ and DM(zeff)/rdrag = 19.17 ± 0.99 with DH and DM the Hubble and comoving angular distances, respectively. These results are in agreement with those obtained in configuration space, thus allowing a consensus measurement of fσ8(zeff) = 0.315 ± 0.095, $D_{\rm H}(z_{\rm eff})/r_{\rm drag} = 19.6_{-2.1}^{+2.2}$ and DM(zeff)/rdrag = 19.5 ± 1.0. This measurement is consistent with a flat ΛCDM model with Planck parameters.

How can powerful countries be made to comply with international law? This question has been widely discussed by scholars. This paper expounds from three aspects: theory, famous case analysis and proposed solutions. First, how this problem came into being, secondly, its impact, and finally, how the country should deal with this problem.

We present the measurements of the small-scale clustering for the emission-line galaxy (ELG) sample from the extended Baryon Oscillation Spectroscopic Survey (eBOSS) in the Sloan Digital Sky Survey IV (SDSS-IV). We use conditional abundance matching method to interpret the clustering measurements from 0.34 to |$70\, h^{-1}\, \textrm {Mpc}$|⁠. In order to account for the correlation between properties of ELGs and their environment, we add a secondary connection between star formation rate of ELGs and halo accretion rate. Three parameters are introduced to model the ELG [O  ii ] luminosity and to mimic the target selection of eBOSS ELGs. The parameters in our models are optimized using Markov Chain Monte Carlo (MCMC) method. We find that by conditionally matching star formation rate of galaxies and the halo accretion rate, we are able to reproduce the eBOSS ELG small-scale clustering within 1σ error level. Our best-fitting model shows that the eBOSS ELG sample only consists of |$\sim 12{{\ \rm per\ cent}}$| of all star-forming galaxies, and the satellite fraction of eBOSS ELG sample is 19.3 per cent. We show that the effect of assembly bias is |$\sim 20{{\ \rm per\ cent}}$| on the two-point correlation function and |$\sim 5{{\ \rm per\ cent}}$| on the void probability function at scale of |$r\sim 20 \, h^{-1}\, \rm Mpc$|⁠. [ABSTRACT FROM AUTHOR]

We present 2000 mock galaxy catalogues for the analysis of baryon acoustic oscillations (BAOs) in the Emission Line Galaxy (ELG) sample of the extended Baryon Oscillation Spectroscopic Survey Data Release 16 (eBOSS DR16). Each mock catalogue has a number density of |$6.7 \times 10^{-4} h^3 \rm Mpc^{-3}$|⁠ , covering a redshift range from 0.6 to 1.1. The mocks are calibrated to small-scale eBOSS ELG clustering measurements at scales of |$\lesssim 30\, h^{-1}$| Mpc. The mock catalogues are generated using a combination of GaLAxy Mocks (GLAM) simulations and the quick particle-mesh (QPM) method. GLAM simulations are used to generate the density field, which is then assigned dark matter haloes using the QPM method. Haloes are populated with galaxies using a halo occupation distribution. The resulting mocks match the survey geometry and selection function of the data, and have slightly higher number density that allows room for systematic analysis. The large-scale clustering of mocks at the BAO scale is consistent with data and we present the correlation matrix of the mocks. [ABSTRACT FROM AUTHOR]

Chlorella viruses produce N‐linked glycoproteins with carbohydrate moieties that differ in structure from all other N‐linked glycans. In addition, unlike most viruses, these organisms do not hijack the biosynthetic machinery of the host to make glycocoproteins; instead, they produce their own carbohydrate‐processing enzymes. A better understanding of the function and assembly of these fascinating and structurally‐unprecedented glycans requires access to probe molecules. This work describes the first synthesis of a chlorella virus N‐linked glycan, a highly branched hexasaccharide that contains the pentasaccharide present in all of the >15 structures reported to date. The target molecule includes a glucosyl‐asparagine linkage and a "hyperbranched" fucose residue in which all of the hydroxyl groups are glycosylated. Both convergent and linear approaches were investigated with the latter being successful in providing the target in 16 steps and 13 % overall yield. A linear approach yields the first total synthesis of an N‐linked glycan from chlorella virus glycoproteins. Probes of this type will be indispensable tools in understanding the function and biosynthesis of these structurally fascinating molecules. [ABSTRACT FROM AUTHOR]

Objectives: microRNAs (miRNAs) are small noncoding RNAs that regulate gene expression by mRNA cleavage or translational repression. The miR-200 family is involved in the regulation of various tumor biologic processes including apoptosis, proliferation, invasion, and metastasis. They function mainly as tumor suppressors. In this study, we aim to validate the prognostic significance of miR-200 family using large cohort of primary clear cell renal cell carcinoma (ccRCC) and matched normal tissue and to explore the role of miR-200 family in RCC pathogenesis and progression.Materials and Methods: We analyzed the expression of 3 members of the miR-200 family; miR-141, miR-200b, and miR-200c, between primary ccRCC, matched normal renal tissues, and nonmatched metastatic RCC. We compared clinicopathologic parameter including disease-free survival to miR-200 family expression. Additionally, we validated our results using The Cancer Genome Atlas dataset. We explored functional role of these miRNAs by bioinformatics analyses.Results and Conclusions: Expression of miR-200 family significantly decreased in cancer compared to non-neoplastic tissues. miR-141 and miR-200b were significantly down-regulated in metastatic than primary tumors. There was statistically significant negative association between all 3 miRNAs and tumor size and stage. As binary variables, univariate analyses revealed that miR-141, miR-200b, and miR-200c-positive ccRCC patients have a statistically significant lower chance of disease-recurrence or relapse and multivariate analyses showed miR-200b and miR-200c-positive patients have longer disease-free survival. We could predict disease-free survival better when 2 or more miRNAs were used as a combination. Overall survival analysis using The Cancer Genome Atlas data revealed that miR-200b-positive patients have significantly better survival. These results suggest that miR-141, miR-200b, and miR-200c are independent prognostic markers for ccRCC. Targets of these miRNAs are associated with pathways related to cancer invasion and metastasis, including TRAIL pathway, VEGF and VEGFR signaling network, and epithelial-mesenchymal transition. [ABSTRACT FROM AUTHOR]

The chlorovirus Paramecium bursaria chlorella virus 1 (PBCV-1) is a large dsDNA virus that infects the microalga Chlorella variabilis NC64A. Unlike most other viruses, PBCV-1 encodes most, if not all, of the machinery required to glycosylate its major capsid protein (MCP). The structures of the four N -linked glycans from the PBCV-1 MCP consist of nonasaccharides, and similar glycans are not found elsewhere in the three domains of life. Here, we identified the roles of three virus-encoded glycosyltransferases (GTs) that have four distinct GT activities in glycan synthesis. Two of the three GTs were previously annotated as GTs, but the third GT was identified in this study. We determined the GT functions by comparing the WT glycan structures from PBCV-1 with those from a set of PBCV-1 spontaneous GT gene mutants resulting in antigenic variants having truncated glycan structures. According to our working model, the virus gene a064r encodes a GT with three domains: domain 1 has a β-l-rhamnosyltransferase activity, domain 2 has an α-l-rhamnosyltransferase activity, and domain 3 is a methyltransferase that decorates two positions in the terminal α-l-rhamnose (Rha) unit. The a075l gene encodes a β-xylosyltransferase that attaches the distal d-xylose (Xyl) unit to the l-fucose (Fuc) that is part of the conserved N -glycan core region. Last, gene a071r encodes a GT that is involved in the attachment of a semiconserved element, α-d-Rha, to the same l-Fuc in the core region. Our results uncover GT activities that assemble four of the nine residues of the PBCV-1 MCP N -glycans., (© 2019 Speciale et al.)

Bacterial biofilms are precursors to biofouling by other microorganisms. Understanding their initiation may allow us to design better ways to inhibit them, and thus to inhibit subsequent biofouling. In this study, the ability of confocal Raman microscopy to follow the initiation of biofouling by a marine bacterium, Pseudoalteromonas sp. NCIMB 2021 (NCIMB 2021), in a flow cell, using optical and confocal Raman microscopy, was investigated. The base of the flow cell comprised a cover glass. The cell was inoculated and the bacteria attached to, and grew on, the cover glass. Bright field images and Raman spectra were collected directly from the hydrated biofilms over several days. Although macroscopically the laser had no effect on the biofilm, within the first 24 h cells migrated away from the position of the laser beam. In the absence of flow, a buildup of extracellular substances occurred at the base of the biofilm. When different coatings were applied to cover glasses before they were assembled into the flow cells, the growth rate, structure, and composition of the resulting biofilm was affected. In particular, the ratio of Resonance Raman peaks from cytochrome c (CC) in the extracellular polymeric substances, to the Raman phenylalanine (Phe) peak from protein in the bacteria, depended on both the nature of the surface and the age of the biofilm. The ratios were highest for 24 h colonies on a hydrophobic surface. Absorption of a surfactant with an ethyleneoxy chain into the hydrophobic coating created a surface similar to that given with a simple PEG coating, where bacteria grew in colonies away from the surface rather than along the surface, and CC:Phe ratios were initially low but increased at least fivefold in the first 48 h., (© The Author(s) 2015.)