Exposure to Non-tuberculous Mycobacteria (NTM) varies regionally and may partly explain the disparate outcomes of BCG vaccination and tuberculosis (TB) susceptibility.
We examined NTM sputum ...colonization, associations with clinical characteristics, and tuberculin skin test (TST) responses in an adolescent TB prevalence survey.
Among 5004 adolescents screened, 2281 (45.5 %) were evaluated further. TB and NTM prevalence rates were 0.3 % and 8.0 %, respectively. Among 418 NTM isolates, 103 were unidentifiable, and 315 (75 %) comprised 15 species, the most frequent being M. intracellulare (MAC) (108, 26 %), M. scrofulaceum (96, 23 %) and M. fortuitum (51, 12 %). “NTM colonized” adolescents had less frequent chronic cough and night sweats (adjusted odds ratio aOR 0.62, 95 % confidence interval CI 0.44-0.87and aOR 0.61, CI 0.42–0.89 respectively), and lower TST induration (median 11 mm (interquartile range IQR 0–16) vs 13 mm (IQR 6–17; p = 0.006)) when compared to “NTM not colonized” participants. MAC, but not M. scrofulaceum or M. fortuitum, was associated with decreased TST induration (median 7.5 mm (IQR 0–15) vs 13 mm (IQR 6–17) among “MAC colonized” vs “not colonized”, p = 0.001).
We observed high NTM prevalence rates with species-specific associations with TST induration, consistent with a model of species-dependent heterologous immunity among mycobacteria.
Objectifs La sclérose latérale amyotrophique (SLA) est une maladie dégénérative se traduit par une atteinte du neurone moteur périphérique dans plusieurs territoires et du neurone moteur central. ...L’électrophysiologie joue un rôle fondamental dans le diagnostic de la SLA notamment dans les formes périphériques pures (pseudo-polynévritique). L’électroneuromyogramme (ENMG) confirme l’atteinte du neurone moteur périphérique dans les régions cliniquement atteintes et montre aussi l’atteinte des régions non atteintes cliniquement ; les potentiels évoqués moteurs (PEM) et la triple stimulation (TST) permettent de mettre en évidence l’atteinte du moteur neurone central cliniquement indécelable. Méthodes Il s’agit d’une étude sur 10 patients présentant une atteinte périphérique motrice pure sans signes pyramidaux. Étaient analysées les données cliniques, les scores MRC, pente ASLFRS et les résultats électrophysiologiques de l’ENMG, TST, PEM avec période de silence. Résultats Notre série comprend 10 patients dont 7 hommes et 3 femmes avec un âge moyen de découverte de 58,4 (32–75) ; présentant un déficit moteur pur évoluant en moyenne depuis (14,8 mois). L’ENMG confirme l’atteinte du neurone moteur périphérique chez tous ses patients sur les territoires cliniquement atteints et sur des territoires cliniquement sains. Les PEM réalisés sur nos 10 patients et sur 17 nerfs ulnaires et 16 nerfs péroniers (TA) soit chez 8 de nos patients étaient pathologiques chez un seul malade sur un nerf ulnaire par contre une période de silence pathologique chez 60 % des patients et surtout pathologique sur les segments initialement atteints. Neuf de nos patients ont bénéficié de la TST réalisé sur 15 nerfs ulnaires, elle était pathologique sur 12 nerfs (80 %). Les PEM avec période de silence et la TST ont confirmé ainsi l’atteinte centrale cliniquement indécelable rajoutant ainsi au tableau moteur périphérique pour la pièce manquante du puzzle du diagnostic de la SLA écartant ainsi d’autres étiologies de la corne antérieur. Les résultats étaient aussi corrélés au score MRC et à la pente ALSFRS. Conclusion La forme périphérique pure de la SLA est de diagnostic clinique difficile. L’ENMG met en évidence l’atteinte du neurone moteur périphérique dans les territoires cliniquement atteints et montre des anomalies électriques évocatrices dans les territoires non atteints cliniquement. Les PEM et la TST complète l’ENMG confirme l’atteinte du neurone moteur central et permet ainsi d’établir un diagnostic précoce et de la différencier des autres affections qui peuvent la simuler.
•Thermo-kinetics aspects of isopropyl acetate (IPA) pyrolysis have been studied under combustion conditions of pressures and temperatures.•The accurate ab initio CBS-QB3 composite method and the DFT ...M06–2X and ωB97XD were used.•Rate coefficients were obtained by transition state theory (TST) and statistical Rice–Ramsperger–Kassel–Marcus (RRKM).•Branching ratios results show the domination of the complex bond fission R1 at low temperatures, while the simple bonds fission reactions R7 and R8 dominate at elevated temperatures.
In this work, a comprehensive theoretical study was performed on the pyrolysis mechanism of Isopropyl acetate (IPA) using density functional methods (M06–2X, ωB97XD) and ab initio complete basis set−quadratic Becke3 (CBS-QB3) methods under combustion conditions over temperature ranges 600−1700 K and pressure ranging from 0.001 to 100 atm. The enthalpies of formation (AE), bond dissociation energies (BDEs), ionization energies (IE), and electron affinities (EA) of IPA and its main dissociation were calculated at the CBS-QB3 method and compared with available experimental results. The IPA pyrolysis mechanism was extended to include fourteen channels, seven complex fission reactions, and seven simple bond fission reactions. Among the investigated reactions, the formation of acetic acid and propene can occur through two different pathways; six-membered ring transition state (TS1SMR) or four-membered ring transition state (TS1FMR), with TS1SMR being 17.40 kcal mol−1 more preferable. The effect of temperature and pressure change was investigated using the transition state theory (TST) in conjunction with Wigner (W) tunneling corrections and the Statistical Rice-Ramsperger-Kassel-Marcus (RRKM) theory, respectively. The branching ratios (BR) of all chemical reactions involved were estimated. The results indicate that acetic acid and propene dominate up to 1400 K, but at high temperatures, simple bond fission reactions lead IPA pyrolysis. The BR analysis results are excellent agreement with the obtained BDEs and previous literature on similar biodiesel esters.
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The reaction of O2 with butyl radicals is a key early step in the oxidation of n-butane, which is a prototypical alkane fuel with combustion properties that mimic those of many larger alkanes. ...Current combustion mechanisms employ kinetic descriptions for such radical oxidations that are based on fairly limited information. The present work employs a combination of experiment and theory to probe the kinetics of O2 reacting with both 1- and 2-butyl radicals. The experiments employ laser photolysis to generate butyl radicals and thereby initiate the reaction kinetics. Photoionization mass spectrometric observations of the time-dependent butyl radical concentration yield rate coefficients for the overall reaction. The experiments cover temperatures ranging from 200 to 500 K and He bath gas pressures ranging from 0.3 to 6 Torr. Ab initio transition state theory (TST) based master equation calculations are used to predict the kinetics over a broad range of conditions. The calculations consider both the barrierless R + O2 entrance channel, treated with direct CASPT2 variable reaction coordinate TST, and the decomposition of the RO2 complex to HO2 + alkenes, treated with CCSD(T)/CBS based TST. Theory and experiment are in good agreement, with maximum discrepancies of about 30%, suggesting the appropriateness of the theory based predictions for conditions of greater relevance to combustion. The kinetic description arising from this work should be of considerable utility to combustion modeling of n-butane, as well as of other related saturated hydrocarbons.
In 2000, a subanesthetic dose (0.5 mg/kg i.v.) of the dissociative anesthetic ketamine was reported to have both rapid and robust antidepressant effects in patients diagnosed with major depressive ...disorder and later, ketamine also was shown to be effective in treatment-resistant depressed patients. However, the mechanisms responsible for ketamine's antidepressant effects remain unclear. In 2018, a clinical study reported that pretreatment with the nonselective opioid antagonist naltrexone attenuated the rapid antidepressant effect of ketamine in depressed patients. The current study investigated the potential role of the opioid receptor system in the acute and sustained antidepressant-like and hyperactive effects of ketamine. Mice were tested in the tail suspension test (TST) and differential-reinforcement-of-low-rate responding (DRL) 72 s task which are behavioral screens for antidepressant-like properties. Additionally, open field locomotor activity also was measured. In all behavioral assays, mice were pretreated with the nonselective opioid receptor antagonist naltrexone or saline prior to ketamine administration. The current study found that ketamine (10 mg/kg) produced acute (30 min) and sustained (24 h) antidepressant-like effects in TST, which were attenuated by pretreatment of 2 mg/kg naltrexone. Ketamine (32 mg/kg) also produced an acute antidepressant-like effect in the DRL 72 s task that was attenuated by pretreatment of 2 mg/kg naltrexone. Finally, ketamine (10 and 32 mg/kg) produced hyperactivity in the open field; however, pretreatment with 2 mg/kg naltrexone failed to block the hyperactivity effects ketamine. These results, along with recent clinical findings, suggest that ketamine's antidepressant effects, but not its hyperactive effects, involve activation of the opioid system.
•Ketamine produced both acute and sustained antidepressant-like effects in TST in mice.•Ketamine produced acute antidepressant-like effects in DRL 72 s in mice.•Naltrexone blocked ketamine's acute and sustained antidepressant-like effects.•Ketamine produced hyperactivity in mice that was not blocked by naltrexone.•Ketamine's antidepressant effects may involve activation of the opioid system.
Ti2AlN powder with ∼97 wt% purity has been synthesized at 700 °C (far below all the previously reported temperatures) via molten salt shielded synthesis (MS3) in the air. The effects of sintering ...temperature, holding time, and salt content on its purity and particle size are investigated. The reaction mechanism from reactants to products is disclosed through density functional and transition state theories (DFT and TST). The regulation mechanism in morphology is illustrated by the spinodal decomposition (SD) and phase separation model. When the holding time or salt content improves, the purity increases. Ti2AlN powder synthesized at 700 °C for 2 h with a salt content of 80 wt% exhibits a purity of 97.7 wt%, an average particle size of 13.8 μm, and a uniform layer structure. Ti2AlN is reacted via Ti + Al + TiN→Ti2AlN, which occurs when the free energy of Ti–Al–TiN exceeds that of Ti2AlN by the energy barrier of 4.08 eV, and it is a necessary condition for achieving the result that the synthesis is completed at the critical temperature of 700 °C. Grain growth and the surface tension of molten salt regulate the morphology. The above mechanism has been revealed for the first time in this field to date.
The relationship between the coal nitrogen chemistry and the emission of NOx is a topic attracting wide-ranging interest due to its adverse impact on the environment. In this work, a comprehensive ...reaction network is proposed based on the DFT calculations to show the possible oxidation mechanisms of benzoquinoline that may result in the generation of NOx and/or other nitrogen-containing species. The kinetics of the reaction network is evaluated by Chemkin using the rate parameters computed from the transition state theory (TST). The first important contribution is the consideration of the role of O2 in the oxidation reaction, with the indication that the addition of O2 to N atom and neighboring CN bond that can activate the C(N) species will be more competitive than the addition of O2 to neighboring CC towards the benzoquinoline oxidation. Furthermore, benzoquinoline will be directly oxidated to NO and indirectly to HCN with the help of H radical. The H radical will promote the rupture of the CN bond, and thus accelerate the generation of HCN. The second important contribution is the obtained transition of the reaction mechanism over the temperature range of 1173–1273 K. The increase of the temperature will shift back the low-temperature formed NO to some important intermediates that can lead to the release of HCN. The mechanisms reported are capable of reproducing some general observations that previously did not have a fundamental explanation, and will be important for the future design of the low-NOx combustion technology.
Latent tuberculosis infection (LTBI) is a subclinical mycobacterial infection defined on the basis of cellular immune response to mycobacterial antigens. The tuberculin skin test (TST) and the ...interferon gamma release assay (IGRA) are currently used to establish the diagnosis of LTB. However, neither TST nor IGRA is useful to discriminate between active and latent tuberculosis. Moreover, these tests cannot be used to predict whether an individual with LTBI will develop active tuberculosis (TB) or whether therapy for LTBI could be effective to decrease the risk of developing active TB. Therefore, in this article, we review current approaches and some efforts to identify an immunological marker that could be useful in distinguishing LTBI from TB and in evaluating the effectiveness of treatment of LTB on the risk of progression to active TB.
•Tuberculosis (TB) infection accounts for 2 billion people worldwide•TB infection is defined by immune response detection without clinical active disease•Tests for TB infection diagnosis lack ...accuracy to identify progressors to disease•Preventive therapy is a strategy to control TB spread worldwide•A TB infection registry is crucial for public health issues of TB control
The World Health Organization estimated that a quarter of the global population is infected by Mycobacterium tuberculosis (Mtb). A better control of tuberculosis (TB) is based on the ability to detect Mtb infection, identifying the progressors to TB disease, undergoing to preventive therapy and implementing strategies to register the infections and treatment completion.
we reviewed the literature regarding the tests available for TB infection diagnosis, the preventive therapies options and the cascade of care for controlling TB at a public health level.
current tests for TB infection diagnosis as IFN-γ release assays or tuberculin skin tests are based on the detection of an immune response to Mtb in the absence of clinical disease. The main limit is their low accuracy to detect progressors to disease. New preventive treatments are available with short duration that are associated with better adherence. Options to register TB infections are presented.
Tests to diagnose TB infection are available but they lack accuracy to identify the progressors from infection to TB disease. Shorter preventive TB therapy are available but need to be implemented worldwide. A TB infection registry is crucial for improving the cascade of care leading to a better TB control.
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