Organ and tissue loss through disease and injury motivate the development of therapies that can regenerate tissues and decrease reliance on transplantations. Regenerative medicine, an ...interdisciplinary field that applies engineering and life science principles to promote regeneration, can potentially restore diseased and injured tissues and whole organs. Since the inception of the field several decades ago, a number of regenerative medicine therapies, including those designed for wound healing and orthopedics applications, have received Food and Drug Administration (FDA) approval and are now commercially available. These therapies and other regenerative medicine approaches currently being studied in preclinical and clinical settings will be covered in this review. Specifically, developments in fabricating sophisticated grafts and tissue mimics and technologies for integrating grafts with host vasculature will be discussed. Enhancing the intrinsic regenerative capacity of the host by altering its environment, whether with cell injections or immune modulation, will be addressed, as well as methods for exploiting recently developed cell sources. Finally, we propose directions for current and future regenerative medicine therapies.
The properties and synthesis of titanium oxide nanomaterials are discussed. Various methods for the creation of such materials, such as the direct oxidation, hydrothermal, and solvothermal method are ...presented.
Cosmic ray pressure gradients transfer energy and momentum to extraplanar gas in disk galaxies, potentially driving significant mass loss as galactic winds. This may be particularly important for ...launching high-velocity outflows of "cool" (T 104 K) gas. We study cosmic ray-driven disk winds using a simplified semi-analytic model assuming streamlines follow the large-scale gravitational potential gradient. We consider scaled Milky Way-like potentials including a disk, bulge, and halo with a range of halo velocities VH = 50-300 and streamline footpoints with radii in the disk R0 = 1-16 kpc at a height of 1 kpc. Our solutions cover a wide range of footpoint gas velocity u0, magnetic-to-cosmic ray pressure ratio, gas-to-cosmic ray pressure ratio, and angular momentum. Cosmic ray streaming at the Alfvén speed enables the effective sound speed Ceff to increase from the footpoint to a critical point where Ceff,c = uc ∼ VH; this differs from thermal winds, in which Ceff decreases outward. The critical point is typically at a height of 1-6 kpc from the disk, increasing with VH, and the asymptotic wind velocity exceeds the escape speed of the halo. Mass-loss rates are insensitive to the footpoint values of the magnetic field and angular momentum. In addition to numerical parameter space exploration, we develop and compare to analytic scaling relations. We show that winds have mass-loss rates per unit area up to , where 0 is the footpoint cosmic ray pressure and u0 is set by the upwelling of galactic fountains. The predicted wind mass-loss rate exceeds the star formation rate for VH 200 and u0 = 50 , a typical fountain velocity.
Multi-GeV electron beams with energy up to 4.2 GeV, 6% rms energy spread, 6 pC charge, and 0.3 mrad rms divergence have been produced from a 9-cm-long capillary discharge waveguide with a plasma ...density of ≈7×10¹⁷ cm⁻³, powered by laser pulses with peak power up to 0.3 PW. Preformed plasma waveguides allow the use of lower laser power compared to unguided plasma structures to achieve the same electron beam energy. A detailed comparison between experiment and simulation indicates the sensitivity in this regime of the guiding and acceleration in the plasma structure to input intensity, density, and near-field laser mode profile.
A look at the use of semiconductor-based photocatalytic hydrogen generation as an alternative energy source is presented. Issues that still need to be examined include chemical composition and ...electronic properties.
Abstract The mechanical properties of the microenvironment and direct contact-mediated cell-cell interactions are two variables known to be important in the determination of stem cell differentiation ...fate, but little is known about the interplay of these cues. Here, we use a micropatterning approach on polyacrylamide gels of tunable stiffnesses to study how homotypic cell-cell contacts and mechanical stiffness affect different stages of osteogenesis of mesenchymal stem cells (MSCs). Nuclear localization of transcription factors associated with osteogenesis depended on substrate stiffness and was independent of the degree of cell-cell contact. However, expression of alkaline phosphatase, an early protein marker for osteogenesis, increased only in cells with both direct contact with neighboring cells and adhesion to stiffer substrates. Finally, mature osteogenesis, as assessed by calcium deposition, was low in micropatterned cells, even on stiff substrates and in multicellular clusters. These results indicate that substrate stiffness and the presence of neighboring cells regulate osteogenesis in MSCs.
Virtual photons can mediate interaction between atoms, resulting in an energy shift known as a collective Lamb shift. Observing the collective Lamb shift is challenging, since it can be obscured by ...radiative decay and direct atom-atom interactions. Here, we place two superconducting qubits in a transmission line terminated by a mirror, which suppresses decay. We measure a collective Lamb shift reaching 0.8% of the qubit transition frequency and twice the transition linewidth. We also show that the qubits can interact via the transmission line even if one of them does not decay into it.
Stimuli-responsive materials activated by biological signals play an increasingly important role in biotechnology applications. We exploit the programmability of CRISPR-associated nucleases to ...actuate hydrogels containing DNA as a structural element or as an anchor for pendant groups. After activation by guide RNA-defined inputs, Cas12a cleaves DNA in the gels, thereby converting biological information into changes in material properties. We report four applications: (i) branched poly(ethylene glycol) hydrogels releasing DNA-anchored compounds, (ii) degradable polyacrylamide-DNA hydrogels encapsulating nanoparticles and live cells, (iii) conductive carbon-black-DNA hydrogels acting as degradable electrical fuses, and (iv) a polyacrylamide-DNA hydrogel operating as a fluidic valve with an electrical readout for remote signaling. These materials allow for a range of in vitro applications in tissue engineering, bioelectronics, and diagnostics.
The cell nucleus is a highly compartmentalized organelle harbouring a variety of dynamic membraneless nuclear bodies. How these subnuclear domains are established and maintained is not well ...understood. Here, we investigate the molecular mechanism of how one nuclear body, the paraspeckle, is assembled and organized. Paraspeckles are discrete ribonucleoprotein bodies found in mammalian cells and implicated in nuclear retention of hyperedited mRNAs. We developed a live-cell imaging system that allows for the inducible transcription of Men /β (also known as Neat1; ref. 12) noncoding RNAs (ncRNAs) and the direct visualization of the recruitment of paraspeckle proteins. Using this system, we demonstrate that Men /β ncRNAs are essential to initiate the de novo assembly of paraspeckles. These newly formed structures effectively harbour nuclear-retained mRNAs confirming that they are bona fide functional paraspeckles. By three independent approaches, we show that it is the act of Men /β transcription, but not ncRNAs alone, that regulates paraspeckle maintenance. Finally, fluorescence recovery after photobleaching (FRAP) analyses supported a critical structural role for Men /β ncRNAs in paraspeckle organization. This study establishes a model in which Men /β ncRNAs serve as a platform to recruit proteins to assemble paraspeckles.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The objective of this study was to investigate changes in the composition of mucosa-associated bacterial community, the morphology of the small intestinal epithelia, and the gene expressions of ...junction proteins and inflammatory cytokines in the small intestines of dairy cattle fed a high-grain (HG) diet. A total of 12 ruminally cannulated Holstein cows in mid-lactation were randomly fed either a conventional (CON) diet (40% concentrate, dry matter basis) or an HG diet (60% concentrate, dry matter basis) for 4 wk. At the end of the feeding trial, all the cows were slaughtered and then examined for changes in the small intestinal mucosa-associated bacterial communities using 16S full-length amplicon sequencing. Furthermore, the gene expression of tight junction proteins and inflammatory cytokines in the small intestinal epithelium were studied using real-time quantitative PCR. The results of nonmetric multidimensional scaling plots showed that an HG diet altered the composition of mucosa-associated bacterial communities in the jejunum and ileum. The HG feeding only increased the numbers of operational taxonomic units in the mucosa-associated bacterial community in the jejunum. At the genus level, the HG diet increased the abundance of uncultured Succinivibrionaceae and Lachnospiraceae incertae sedis in the duodenal mucosa, whereas the proportions of Veillonella and Selenomonas increased in the jejunal mucosa. Compared with the CON group, the proportions of Acetitomaculum in both the jejunal and the ileal mucosa were higher in the HG group. Analysis via PICRUSt2 (version 2.2.0-b) suggested that the HG diet increased the abundance of genes related to biodegradation of xenobiotics in the jejunal mucosa and the abundance of genes related to immune disease in the ileal mucosa. Additionally, the group fed an HG diet had higher concentrations of lipopolysaccharides in the jejunal and ileal digesta. The HG feeding caused a downregulation of the mRNA expression of occludin and ZO-1 in the jejunal epithelium, as well as of claudin-1, claudin-4, and ZO-1 in the ileal epithelium. Moreover, the HG diet caused an increase in the mRNA expression of IL-1β, IL-2, and IFN-γ in the jejunal epithelium, but a higher expression of IL-2 and IFN-γ in the ileal epithelium. Correlation analysis revealed that the alteration of lipopolysaccharide levels and mucosa-associated bacterial community might partly contribute to changes in the expression of the epithelial cytokines in the jejunum and ileum during HG feeding. These findings suggest that microbiota residing in the small intestine provide essential health benefits to host dairy cattle.
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