Changes of early post-traumatic osteoarthritis in an ovine model of simulated ACL reconstruction are associated with transient acute post-injury synovial inflammation and tissue catabolism

SummaryThe study described here tested the hypothesis that early intra-articular inflammation is associated with the development of post-traumatic osteoarthritis (PTOA) in a sheep model. We extended previously published work in which we investigated joint gross morphology and synovial mRNA expression of inflammatory and catabolic molecules 2 weeks after anatomic Anterior cruciate ligament (ACL) autograft reconstructive surgery (ACL-R). The same variables have been analyzed at 20 weeks post surgery together with new experimental variables at both time points. Animals were sacrificed at 20 weeks post ACL-R surgery and their joints graded for signs of PTOA. Synovial samples were harvested for histological grading plus mRNA and protein analysis for a panel of inflammatory and catabolic molecules. The mRNA expression levels for this panel plus connective tissue matrix turnover molecules were also investigated in cartilage samples. Results of gross morphological assessments at 20 weeks post surgery showed some changes consistent with early OA, but indicated little progression of damage from the 2 week time point. While significant alterations in mRNA levels for synovial inflammatory and catabolic molecules were detected at 2 weeks, values had normalized by 20 weeks. Similarly, all mRNA expression levels for inflammatory and catabolic molecules in articular cartilage had returned to normal levels by 20 weeks post ACL-R surgery. We conclude that synovial inflammatory processes are initiated very early after ACL-R surgery and may instigate events that lead to the gross cartilage and joint abnormalities observed as early as 2 weeks. However, the absence of sustained inflammation and joint instability may prevent OA progression

Expression of MUC5AC and MUC5B mucins in normal and cystic fibrosis lung

AbstractHypersecretion of airway mucus is a characteristic feature of chronic airway diseases like cystic fibrosis (CF) and leads via impairment of the muco-ciliary clearance and bacterial superinfection to respiratory failure. The major components of the mucus matrix forming family of mucins in the airways are MUC5AC and MUC5B. To investigate the expression of these glycoproteins in CF, immunohistochemistry was carried out on trachea, bronchi and peripheral lung obtained from CF patients and compared to normal lung tissues. MUC5AC immunohistochemistry demonstrated signals in goblet cells of the epithelial lining. Also, goblet cells inside glandular secretory ducts revealed MUC5AC-positive staining. In comparison to those from normal subjects, CF sections were characterized by inflammatory changes and goblet cell hyperplasia, resulting in increased numbers of MUC5AC-positive cells. Immunohistochemical staining for MUC5B showed abundant staining of submucosal glands and epithelial goblet cells. Inside the glands, the immunoreactivity was restricted to glandular mucous cells. MUC5AC and MUC5B are expressed in the same histological pattern in CF compared to normal tissues with an increase of MUC5AC-positive cells due to goblet cell hyper- and metaplasia

Absence of hole pairing in a simple t-J model on the Shastry-Sutherland lattice

The Shastry-Sutherland model is a two-dimensional frustrated spin model whose ground state is a spin gap state. We study this model doped with one and two holes on a 32-site lattice using exact diagonalization. When t'>0, we find that the diagonal dimer order that exists at half-filling are retained at these moderate doping levels. No other order is found to be favored on doping. The holes are strongly repulsive unless the hopping terms are unrealistically small. Therefore, the existence of a spin gap at half-filling does not guarantee hole-pairing in the present case

GPU-Accelerated Large-Eddy Simulation of Turbulent Channel Flows

High performance computing clusters that are augmented with cost and power efficient graphics processing unit (GPU) provide new opportunities to broaden the use of large-eddy simulation technique to study high Reynolds number turbulent flows in fluids engineering applications. In this paper, we extend our earlier work on multi-GPU acceleration of an incompressible Navier-Stokes solver to include a large-eddy simulation (LES) capability. In particular, we implement the Lagrangian dynamic subgrid scale model and compare our results against existing direct numerical simulation (DNS) data of a turbulent channel flow at Reτ = 180. Overall, our LES results match fairly well with the DNS data. Our results show that the Reτ = 180 case can be entirely simulated on a single GPU, whereas higher Reynolds cases can benefit from a GPU cluster

Visible Sector Supersymmetry Breaking Revisited

We revisit the possibility of "visible sector" SUSY models: models which are straightforward renormalizable extensions of the Minimal Supersymmetric Standard Model (MSSM), where SUSY is broken at tree level. Models of this type were abandoned twenty years ago due to phenomenological problems, which we review. We then demonstrate that it is possible to construct simple phenomenologically viable visible sector SUSY models. Such models are indeed very constrained, and have some inelegant features. They also have interesting and distinctive phenomenology. Our models predict light gauginos and very heavy squarks and sleptons. The squarks and sleptons may not be observable at the LHC. The LSP is a stable very light gravitino with a significant Higgsino admixture. The NLSP is mostly Bino. The Higgs boson is naturally heavy. Proton decay is sufficently and naturally suppressed, even for a cutoff scale as low as 10^8 GeV. The lightest particle of the O'Raifeartaigh sector (the LOP) is stable, and is an interesting cold dark matter candidate.Comment: 23 pages, 3 figures, LaTe

Terahertz emission by diffusion of carriers and metal-mask dipole inhibition of radiation

Terahertz (THz) radiation can be generated by ultrafast photo-excitation of carriers in a semiconductor partly masked by a gold surface. A simulation of the effect taking into account the diffusion of carriers and the electric field shows that the total net current is approximately zero and cannot account for the THz radiation. Finite element modelling and analytic calculations indicate that the THz emission arises because the metal inhibits the radiation from part of the dipole population, thus creating an asymmetry and therefore a net current. Experimental investigations confirm the simulations and show that metal-mask dipole inhibition can be used to create THz emitters.Comment: 9 pages, 5 figures; Fixed figure

Specific Missense Alleles of the Arabidopsis Jasmonic Acid Co-Receptor COI1 Regulate Innate Immune Receptor Accumulation and Function

[EN] Plants utilize proteins containing nucleotide binding site (NB) and leucine-rich repeat (LRR) domains as intracellular innate immune receptors to recognize pathogens and initiate defense responses. Since mis-activation of defense responses can lead to tissue damage and even developmental arrest, proper regulation of NB-LRR protein signaling is critical. RAR1, SGT1, and HSP90 act as regulatory chaperones of pre-activation NB-LRR steady-state proteins. We extended our analysis of mutants derived from a rar1 suppressor screen and present two allelic rar1 suppressor (rsp) mutations of Arabidopsis COI1. Like all other coi1 mutations, coi1(rsp) missense mutations impair Jasmonic Acid (JA) signaling resulting in JA-insensitivity. However, unlike previously identified coi1 alleles, both coi1(rsp) alleles lack a male sterile phenotype. The coi1(rsp) mutants express two sets of disease resistance phenotypes. The first, also observed in coi1-1 null allele, includes enhanced basal defense against the virulent bacterial pathogen Pto DC3000 and enhanced effector-triggered immunity (ETI) mediated by the NB-LRR RPM1 protein in both rar1 and wild-type backgrounds. These enhanced disease resistance phenotypes depend on the JA signaling function of COI1. Additionally, the coi1(rsp) mutants showed a unique inability to properly regulate RPM1 accumulation and HR, exhibited increased RPM1 levels in rar1, and weakened RPM1-mediated HR in RAR1. Importantly, there was no change in the steady-state levels or HR function of RPM1 in coi1-1. These results suggest that the coi1(rsp) proteins regulate NB-LRR protein accumulation independent of JA signaling. Based on the phenotypic similarities and genetic interactions among coi1(rsp), sgt1b, and hsp90.2(rsp) mutants, our data suggest that COI1 affects NB-LRR accumulation via two NB-LRR co-chaperones, SGT1b and HSP90. Together, our data demonstrate a role for COI1 in disease resistance independent of JA signaling and provide a molecular link between the JA and NB-LRR signaling pathways.JLD is a Howard Hughes Medical Institute-Gordon and Betty Moore Foundation Plant Science Investigator. This work was funded by the HHMI-GBMF and by the National Science Foundation (Arabidopsis 2010 Program Grant IOS-0929410 to JLD). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.He, Y.; Chung, E.; Hubert, D.; Tornero Feliciano, P.; Dangl, J. (2012). Specific Missense Alleles of the Arabidopsis Jasmonic Acid Co-Receptor COI1 Regulate Innate Immune Receptor Accumulation and Function. PLoS Genetics. 8:1003018-1003018. doi:10.1371/journal.pgen.1003018S10030181003018

Secondary education reform in Lesotho and Zimbabwe and the needs of rural girls: Pronouncements, policy and practice

Analysis of the educational needs of rural girls in Lesotho and Zimbabwe suggests a number of shortcomings in the current form of secondary education, and ways in which it might be modified so as to serve this sizeable group of students better. Several of the shortcomings, notably in relation to curricular irrelevance and excessive focus on examinations, have long been recognised, including by politicians. Yet political pronouncements are seldom translated into policy, and even where policy is formulated, reforms are seldom implemented in schools. This paper makes use of interviews with educational decision-makers in the two southern African countries and a range of documentary sources to explore why, despite the considerable differences between the two contexts, much needed educational reforms have been implemented in neither

In situ observations of coral spawning and spawn slick at Lankayan Island, Sabah, Malaysia

Sexual reproduction of corals is one of the most important processes for the persistence of coral populations. The Coral Triangle is recognised as a global hotspot of marine biodiversity, harbouring 75% of the world coral species. However, coral reproductive studies remain underrepresented in many reefs in the Coral Triangle. This study reports the coral spawning and spawn slicks occurrences from 2012 to 2019 at Lankayan Island, Malaysia, a small island located in the Sulu Sea at the westernmost boundary of the Coral Triangle. A total of 14 species belonging to three genera and two families were recorded to spawn on the reefs between March and May in 2012–2015 and 2019. Between one and eight species spawned on each observed spawning night. Acropora corals appear to dominate the spawning events based on direct observations on the reefs. Coral-spawn slicks were observed during March to May every year and in October 2019. We observed coral spawning between March and May in Lankayan Island, similar to other localities within the Coral Triangle. © 2021, Senckenberg Gesellschaft für Naturforschung