Meniscal Regeneration: A Cause of Persisting Pain following Total Knee Arthroplasty

Many patients have persisting knee pain following total knee arthroplasty. We report the unusual case of a patient whose chronic lateral and medial knee pain were caused by entrapped regenerated meniscal tissue. This was diagnosed and successfully treated by arthroscopic debridement

Molecular dynamics simulation of polyacrylamide adsorption on calcite

In poorly consolidated carbonate rock reservoirs, solids production risk, which can lead to increased environmental waste, can be mitigated by injecting formation-strengthening chemicals. Classical atomistic molecular dynamics (MD) simulation is employed to model the interaction of polyacrylamide-based polymer additives with a calcite structure, which is the main component of carbonate formations. Amongst the possible calcite crystal planes employed as surrogates of reservoir rocks, the (1 0 4) plane is shown to be the most suitable surrogate for assessing the interactions with chemicals due to its stability and more realistic representation of carbonate structure. The molecular conformation and binding energies of pure polyacrylamide (PAM), hydrolysed polyacrylamide in neutral form (HPAM), hydrolysed polyacrylamide with 33% charge density (HPAM 33%) and sulfonated polyacrylamide with 33% charge density (SPAM 33%) are assessed to determine the adsorption characteristics onto calcite surfaces. An adsorption-free energy analysis, using an enhanced umbrella sampling method, is applied to evaluate the chemical adsorption performance. The interaction energy analysis shows that the polyacrylamide-based polymers display favourable interactions with the calcite structure. This is attributed to the electrostatic attraction between the amide and carboxyl functional groups with the calcite. Simulations confirm that HPAM33% has a lower free energy than other polymers, presumably due to the presence of the acrylate monomer in ionised form. The superior chemical adsorption performance of HPAM33% agrees with Atomic Force Microscopy experiments reported herein

Frequency of conjugative transfer of plasmid-encoded ISEcp1 - blaCTX-M-15 and aac(6')-lb-cr genes in Enterobacteriaceae at a tertiary care center in Lebanon - role of transferases

<p>Abstract</p> <p>Background</p> <p>The frequency of transfer of genes encoding resistance to antimicrobial agents was determined by conjugation in ESBL-producing and/or fluoroquinolone or aminoglycoside resistant Enterobacteriaceae clinical isolates at a tertiary care center in Lebanon. In addition, the role of <it>tra </it>genes encoding transferases in mediating conjugation was assessed.</p> <p>Methods</p> <p>Conjugation experiments were done on 53 ESBL-producing and/or fluoroquinolone resistant <it>E. coli </it>and <it>K. pneumoniae </it>and ESBL-producing <it>S. sonnei </it>isolates. Antimicrobial susceptibility testing on parent and transconjugant isolates, and PCR amplifications on plasmid extracts of the resistance-encoding genes: <it>bla</it>_CTX-M-15with the <it>ISEcp1 </it>insertion sequence, the <it>aac(6')-lb-cr </it>and <it>qnr</it>S genes, as well as <it>tra </it>encoding transferases genes were done. Random amplified polymorphic DNA (RAPD) analysis was performed to demonstrate whether conjugative isolates are clonal and whether they are linked epidemiologically to a particular source.</p> <p>Results</p> <p>Antimicrobial susceptibility testing on transconjugants revealed that 26 out of 53 (49%) ESBL-producing <it>Enterobacteriaceae </it>were able to transfer antimicrobial resistance to the recipients. Transfer of high-level resistance to the transconjugants encoded by the <it>bla</it>_CTX-M-15gene downstream the <it>ISEcp1 </it>insertion sequence against 3rd generation cephalosporins, and of low-level resistance against ciprofloxacin, and variable levels of resistance against aminoglycosides encoded by <it>aac(6')-lb-cr </it>gene, were observed in transconjugants. <it>tra </it>encoding transferase genes were detected exclusively in conjugative isolates.</p> <p>Conclusion</p> <p>In conclusion, the frequency of transfer of antimicrobial resistance in non clonal <it>Enterobacteriaceae </it>at the tertiary care center by conjugation was 49%. Conjugation occurred in isolates expressing the <it>tra </it>encoding transferase genes. Multiple conjugative strains harboring the plasmid encoded antimicrobial resistant genes were circulating in the medical center. Molecular epidemiology analysis showed that conjugative isolates are neither clonal nor linked to a particular site and transfer of antimicrobial resistance is by horizontal transfer of plasmids.</p

Solving the discretised multiphase flow equations with interface capturing on structured grids using machine learning libraries

The authors would like to acknowledge the following EPSRC grants: the PREMIERE programme grant, “AI to enhance manufacturing, energy, and healthcare” (EP/T000414/1); ECO-AI, “Enabling CO capture and storage using AI” (EP/Y005732/1); MUFFINS, “MUltiphase Flow-induced Fluid-flexible structure InteractioN in Subsea” (EP/P033180/1); WavE-Suite, “New Generation Modelling Suite for the Survivability of Wave Energy Convertors in Marine Environments” (EP/V040235/1); INHALE, “Health assessment across biological length scales” (EP/T003189/1); AI-Respire, “AI for personalised respiratory health and pollution” (EP/Y018680/1); RELIANT, “Risk EvaLuatIon fAst iNtelligent Tool for COVID19” (EP/V036777/1); and CO-TRACE, “COvid-19 Transmission Risk Assessment Case Studies — education Establishments” (EP/W001411/1). Also, the authors acknowledge the Innovate UK grant D-XPERT, “AI-Powered Total Building Management System“ (TS/Y020324/1). Support from Imperial-X’s Eric and Wendy Schmidt Centre for AI in Science (a Schmidt Futures program) is gratefully acknowledged. The authors state that, for the purpose of open access, a Creative Commons Attribution (CC BY) license will be applied to any Author Accepted Manuscript version relating to this article.Peer reviewe

Laboratory evidence for the non-detection of excited nascent H2 in dark clouds

There has always been a great deal of interest in the formation of H2 as well as in the binding energy released upon its formation on the surface of dust grains. The present work aims at collecting experimental evidence for how the bond energy budget of H2 is distributed between the reaction site and the internal energy of the molecule. So far, the non-detection of excited nascent H2 in dense quiescent clouds could be a sign that either predictions of emission line intensities are not correct or the de-excitation of the newly formed molecules proceeds rapidly on the grain surface itself. In this letter we present experimental evidence that interstellar molecular hydrogen is formed and then rapidly de-excited on the surface of porous water ice mantles. In addition, although we detect ro-vibrationally excited nascent molecules desorbing from a bare non-porous (compact) water ice film, we demonstrate that the amount of excited nascent hydrogen molecules is significantly reduced no matter the morphology of the water ice substrate at 10 K (both on non-porous and on porous water ice) in a regime of high molecular coverage as is the case in dark molecular clouds.Comment: 15 pages, 3 figures, to be published in MNRA

Intrinsic synergistic-topological mechanism versus synergistic-topological matrix in microtubule self-organization

Background In this body of work we investigate the synergistic-topological relationship during self-organization of the microtubule fiber in vitro, which is composed of straight, axially shifted and non-shifted, acentrosomal microtubules under crowded conditions. Methods We used electron microscopy to observe morphological details of ordered straight microtubules. This included the observation of the differences in length distribution between microtubules in ordered and non-ordered phases followed by the observation of the formation of interface gaps between axially shifted and ordered microtubules. We performed calculations to confirm that the principle of summation of pairwise electrostatic forces act between neighboring microtubules all their entire length. Results We have shown that the self-organization of a microtubule fiber imposes a variety of topological restrictions onto its constituting components: (a) tips of axially shifted neighboring microtubules are not in direct contact but rather create an ‘interface gap’; (b) fibers are always composed of a restricted number of microtubules at given solution conditions; (c) the average length of microtubules that constitute a fiber is always shorter than that of microtubules outside a fiber; (d) the length distribution of microtubules that constitute a fiber is narrower than that of microtubules outside a fiber and this effect is more pronounced at higher GTP-tubulin concentrations; (e) a cooperative motion of fiber microtubules due to actualization of the summation principle of pairwise electrostatic forces; (f) appearance of local GTP-tubulin depletion immediately in front of the tips of fiber microtubules. Conclusion Overall our data indicate that under crowded conditions in vitro, the self-organization of a microtubule fiber is governed by an intrinsic synergistic-topological mechanism, which in conjunction with the topological changes, GTP-tubulin depletion, and cooperative motion of fiber constituting microtubules, may generate and maintain a ‘synergistic-topological matrix’. Failure of the mechanism to form biologically feasible microtubule synergistic-topological matrix may, per se, precondition tumorigenesis. © 2014 BioMed Central Lt

Water formation at low temperatures by surface O2 hydrogenation I: characterization of ice penetration

Water is the main component of interstellar ice mantles, is abundant in the solar system and is a crucial ingredient for life. The formation of this molecule in the interstellar medium cannot be explained by gas-phase chemistry only and its surface hydrogenation formation routes at low temperatures (O, O2, O3 channels) are still unclear and most likely incomplete. In a previous paper we discussed an unexpected zeroth-order H2O production behavior in O2 ice hydrogenation experiments compared to the first-order H2CO and CH3OH production behavior found in former studies on hydrogenation of CO ice. In this paper we experimentally investigate in detail how the structure of O2 ice leads to this rare behavior in reaction order and production yield. In our experiments H atoms are added to a thick O2 ice under fully controlled conditions, while the changes are followed by means of reflection absorption infrared spectroscopy (RAIRS). The H-atom penetration mechanism is systematically studied by varying the temperature, thickness and structure of the O2 ice. We conclude that the competition between reaction and diffusion of the H atoms into the O2 ice explains the unexpected H2O and H2O2 formation behavior. In addition, we show that the proposed O2 hydrogenation scheme is incomplete, suggesting that additional surface reactions should be considered. Indeed, the detection of newly formed O3 in the ice upon H-atom exposure proves that the O2 channel is not an isolated route. Furthermore, the addition of H2 molecules is found not to have a measurable effect on the O2 reaction channel.Comment: 1 page, 1 figur

Progression of Clinical Features in Lewy Body Dementia Can Be Detected Over 6 Months

Copyright \ua9 2021 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.OBJECTIVE: This study aimed to quantify the trajectory and magnitude of change of the key clinical features and corresponding symptom domains of dementia with Lewy bodies (DLB) and Parkinson disease dementia (PDD), including global cognition, parkinsonism, recurrent visual hallucinations, cognitive fluctuations, and sleep disturbance. METHODS: One hundred sixteen patients with Lewy body dementia (DLB = 72, PDD = 44) underwent assessment at baseline and 3 and 6 months as part of a prospective multicenter randomized controlled trial. Linear mixed models were constructed for core outcome measures using the Mini-Mental State Examination (MMSE), motor section of the Unified Parkinson\u27s Disease Rating Scale (UPDRS-III), Dementia Cognitive Fluctuations Scale (DCFS), and Neuropsychiatric Inventory (NPI). RESULTS: Within the time frame of our study (6 months), we were able to identify a significant cognitive decline of 1.3 points on the MMSE (p = 0.002) and significant worsening of motor parkinsonism with an increase in UPDRS-III score of 3.2 points (p = 0.018). Fluctuation severity also increased using the DCFS with a 6-month change in score of 1.3 points (p = 0.001). Uniquely, a signal for increased severity of sleep symptoms of 1.2 points (NPI-sleep) was also detectable (p = 0.04). Significant changes in neuropsychiatric symptoms were not detected. There was no difference in rates of change of scores between DLB and PDD. DISCUSSION: Clinically significant rates of change in core clinical features can be detected and quantified in Lewy body dementia over a relatively short period (6 months) using common clinical instruments and thus may be useful as clinical endpoints for therapeutic trials of disease-modifying and symptomatic agents