Polyethylene wear particles play a role in development of osteoarthritis via detrimental effects on cartilage, meniscus, and synovium

SummaryObjectiveWhile ultra-high molecular weight polyethylene (UHMWPE) wear particles are known to cause periprosthetic osteolysis, its interaction with other intra-articular tissues in the case of partial joint arthroplasties is not well understood. We hypothesized that UHMWPE particles per se would interact with intra-articular tissue, which by acting as inflammatory reservoirs, would subsequently induce osteoarthritic (OA) changes. Our goal was to assess the inflammatory response, phagocytic activity, as well as apoptosis of intra-articular cells in the presence of UHMWPE particles in vitro, and the in vivo response of those tissues after intra-articular injection of particles in a murine model.DesignThree cell types were used for the in vitro study; chondrocytes, meniscal fibrochondrocytes, and synoviocytes. Each cell type was cultured with two different concentrations of UHMWPE particles. Pro-inflammatory cytokine production, phagocytosis, and apoptosis were analyzed. In vivo experiments were done by injecting two concentrations of UHMWPE particles into normal and murine OA model knee joints.ResultsIn vitro experiments showed that UHMWPE particles increase pro-inflammatory cytokine and mediator (IL-1β, IL-6, TNF-α, Nitric Oxide, and Prostaglandin E2) production, phagocytosis of particles, and apoptosis in all cell types. In vivo experiment showed degeneration of cartilage and meniscus, as well as synovitis after particle injection.ConclusionsUHMWPE wear particles per se exert detrimental effects in cartilage, synovium, and meniscus of the knee joint resulting in pro-inflammatory cytokine release, phagocytosis of particles and apoptosis. Particles induced and exacerbated OA changes in a murine model

Boty-II, a novel LTR retrotransposon in Botrytis cinerea B05.10 revealed by genomic sequence

Botrytis cinerea is a necrotrophic pathogen causing pre- and post-harvest diseases in at least 235 plant species. It manifests extraordinary genotype and phenotype variation. One of the causes of this variation is transposable elements. Two transposable elements have been discovered in this fungus, the retrotransposon (Boty), and the transposon (Flipper). In this work, two complete (Boty-II-76 and Boty-II-103) and two partial (Boty-II-95 and Boty-II-141) long terminal repeat (LTR) retrotransposons were identified by an in silico genomic sequence analysis. Boty-II-76 and Boty-II-103 contain 6439 bp nucleotides with a pair of LTRs at both ends, and an internal deduced pol gene encoding a polyprotein with reverse transcriptase and DDE integrase domains. They are flanked by 5 bp direct repeats (ACCAT, CTTTC). In Boty-II-141, two LTRs at both ends, and a partial internal pol gene encoding a protein with a DDE integrase domain were identified. In Boty-II-95, a right LTR and a partial internal pol gene encoding a protein with no conserved domains were identified. Boty-II uses a self-priming mechanism to initiate synthesis of reverse transcripts. The sequence of the presumed primer binding site for first-strand reverse transcription is 5'-TTGTACCAT-3'. The polypurine-rich sequence for plus-strand DNA synthesis is 5'-GCCTTGAGCGGGGGGTAC-3'. Fourteen Boty-II LTRs that contain 125-158 bp nucleotides and share 69.1 ~ 100% identities with the short inverted terminal repeats of 5 bp (TGTCA\u2026TGACA) were discovered. Analysis of structural features and phylogeny revealed that Boty-II is a novel LTR retrotransposon. It could potentially be used as a novel molecular marker for the investigation of genetic variation in B. cinerea

Crystal Structures of the HslVU Peptidase–ATPase Complex Reveal an ATP-Dependent Proteolysis Mechanism

AbstractBackground: The bacterial heat shock locus HslU ATPase and HslV peptidase together form an ATP-dependent HslVU protease. Bacterial HslVU is a homolog of the eukaryotic 26S proteasome. Crystallographic studies of HslVU should provide an understanding of ATP-dependent protein unfolding, translocation, and proteolysis by this and other ATP-dependent proteases.Results: We present a 3.0 Å resolution crystal structure of HslVU with an HslU hexamer bound at one end of an HslV dodecamer. The structure shows that the central pores of the ATPase and peptidase are next to each other and aligned. The central pore of HslU consists of a GYVG motif, which is conserved among protease-associated ATPases. The binding of one HslU hexamer to one end of an HslV dodecamer in the 3.0 Å resolution structure opens both HslV central pores and induces asymmetric changes in HslV.Conclusions: Analysis of nucleotide binding induced conformational changes in the current and previous HslU structures suggests a protein unfolding–coupled translocation mechanism. In this mechanism, unfolded polypeptides are threaded through the aligned pores of the ATPase and peptidase and translocated into the peptidase central chamber

A Purcell-enabled monolayer semiconductor free-space optical modulator

Dephasing and non-radiative decay processes limit the performance of a wide variety of quantum devices at room temperature. Here we illustrate a general pathway to notably reduce the detrimental impact of these undesired effects through photonic design of the device electrodes. Our design facilitates a large Purcell enhancement that speeds up competing, desired radiative decay while also enabling convenient electrical gating and charge injection functions. We demonstrate the concept with a free-space optical modulator based on an atomically thin semiconductor. By engineering the plasmonic response of a nanopatterned silver gate pad, we successfully enhance the radiative decay rate of excitons in a tungsten disulfide monolayer by one order of magnitude to create record-high modulation efficiencies for this class of materials at room temperature. We experimentally observe a 10% reflectance change as well as 3 dB signal modulation, corresponding to a 20-fold enhancement compared with modulation using a suspended monolayer in vacuum. We also illustrate how dynamic control of light fields can be achieved with designer surface patterns. This research highlights the benefits of applying radiative decay engineering as a powerful tool in creating high-performance devices that complements substantial efforts to improve the quality of materials.</p

Another Two Dark Energy Models Motivated from Karolyhazy Uncertainty Relation

The K$\acute{\text{a}}$rolyh$\acute{\text{a}}$zy uncertainty relation indicates that there exists the minimal detectable cell $\delta t^{3}$ over the region $t^3$ in Minkowski spacetime. Due to the energy-time uncertainty relation, the energy of the cell $\delta t^3$ can not be less $\delta t^{-1}$. Then we get a new energy density of metric fluctuations of Minkowski spacetime as $\delta t^{-4}$. Motivated by the energy density, we propose two new dark energy models. One model is characterized by the age of the universe and the other is characterized by the conformal age of the universe. We find that in the two models, the dark energy mimics a cosmological constant in the late time.Comment: 10 pages, 5 figures, References are adde

Solidification of Al alloys under electromagnetic pulses and characterization of the 3D microstructures under synchrotron x-ray tomography

A novel programmable electromagnetic pulse device was developed and used to study the solidification of Al-15 pct Cu and Al-35 pct Cu alloys. The pulsed magnetic fluxes and Lorentz forces generated inside the solidifying melts were simulated using finite element methods, and their effects on the solidification microstructures were characterized using electron microscopy and synchrotron X-ray tomography. Using a discharging voltage of 120 V, a pulsed magnetic field with the peak Lorentz force of ~1.6 N was generated inside the solidifying Al-Cu melts which were showed sufficiently enough to disrupt the growth of the primary Al dendrites and the Al2Cu intermetallic phases. The microstructures exhibit a strong correlation to the characteristics of the applied pulse, forming a periodical pattern that resonates the frequency of the applied electromagnetic field

Modulated Entanglement Evolution Via Correlated Noises

We study entanglement dynamics in the presence of correlated environmental noises. Specifically, we investigate the quantum entanglement dynamics of two spins in the presence of correlated classical white noises, deriving Markov master equation and obtaining explicit solutions for several interesting classes of initial states including Bell states and X form density matrices. We show how entanglement can be enhanced or reduced by the correlation between the two participating noises.Comment: 9 pages, 4 figures. To be published in Quantum Information Processing, special issue on Quantum Decoherence and Entanglemen

The rms-flux relations in different branches in Cyg X-2

In this paper, the rms-flux (root mean square-flux) relation along the Z-track of the bright Z-Source Cyg X-2 is analyzed using the observational data of Rossi X-ray Timing Explorer (RXTE). Three types of rms-flux relations, i.e. positive, negative, and 'arch'-like correlations are found in different branches. The rms is positively correlated with flux in normal branch (NB), but anti-correlated in the vertical horizontal branch (VHB). The rms-flux relation shows an 'arch'-like shape in the horizontal branch (HB). We also try to explain this phenomenon using existing models.Comment: Accepted for publication in Astrophysics & Space Scienc

Thermostatistics of deformed bosons and fermions

Based on the q-deformed oscillator algebra, we study the behavior of the mean occupation number and its analogies with intermediate statistics and we obtain an expression in terms of an infinite continued fraction, thus clarifying successive approximations. In this framework, we study the thermostatistics of q-deformed bosons and fermions and show that thermodynamics can be built on the formalism of q-calculus. The entire structure of thermodynamics is preserved if ordinary derivatives are replaced by the use of an appropriate Jackson derivative and q-integral. Moreover, we derive the most important thermodynamic functions and we study the q-boson and q-fermion ideal gas in the thermodynamic limit.Comment: 14 pages, 2 figure