This study investigated changes in heart rate variability (HRV) in elite Nordic-skiers to characterize different types of "fatigue" in 27 men and 30 women surveyed from 2004 to 2008. R-R intervals ...were recorded at rest during 8 min supine (SU) followed by 7 min standing (ST). HRV parameters analysed were powers of low (LF), high (HF) frequencies, (LF+HF) (ms(2)) and heart rate (HR, bpm). In the 1 063 HRV tests performed, 172 corresponded to a "fatigue" state and the first were considered for analysis. 4 types of "fatigue" (F) were identified: 1. F(HF(-)LF(-))SU_ST for 42 tests: decrease in LFSU (- 46%), HFSU (- 70%), LFST (- 43%), HFST (- 53%) and increase in HRSU (+ 15%), HRST (+ 14%). 2. F(LF(+) SULF(-) ST) for 8 tests: increase in LFSU (+ 190%) decrease in LFST (- 84%) and increase in HRST (+ 21%). 3. F(HF(-) SUHF(+) ST) for 6 tests: decrease in HFSU (- 72%) and increase in HFST (+ 501%). 4. F(HF(+) SU) for only 1 test with an increase in HFSU (+ 2161%) and decrease in HRSU (- 15%). Supine and standing HRV patterns were independently modified by "fatigue". 4 "fatigue"-shifted HRV patterns were statistically sorted according to differently paired changes in the 2 postures. This characterization might be useful for further understanding autonomic rearrangements in different "fatigue" conditions.
Optical confinement (OC) structures the optical field and amplifies light intensity inside atmospheric aerosol particles, with major consequences for sunlight-driven aerosol chemistry. Although ...theorized, the OC-induced spatial structuring has so far defied experimental observation. Here, x-ray spectromicroscopic imaging complemented by modeling provides direct evidence for OC-induced patterning inside photoactive particles. Single iron(III)-citrate particles were probed using the iron oxidation state as a photochemical marker. Based on these results, we predict an overall acceleration of photochemical reactions by a factor of two to three for most classes of atmospheric aerosol particles. Rotation of free aerosol particles and intraparticle molecular transport generally accelerate the photochemistry. Given the prevalence of OC effects, their influence on aerosol particle photochemistry should be considered by atmospheric models.
The partitioning of components between droplets and the gas phase in e-cigarette aerosols has a significant impact on deposition within the respiratory tract. However, exclusive detection of droplet ...composition has, so far, been elusive. Consequently, the dynamics of partitioning between droplets and the gas phase remains unknown. Here, we combine optical trapping of single droplets with in situ Raman scattering for destruction-free monitoring of e-cigarette droplet composition with a time resolution of seconds. We find that the initial droplet composition is very close to the composition of the e-liquid. Upon dilution with air, the droplet composition changes exponentially on a time scale of seconds, mainly because of evaporation of propylene glycol. The nicotine content in the droplet is controlled by the pH. Nicotine evaporates from the droplets under basic conditions, but remains in the liquid under acidic conditions. These results are crucial for advancing e-liquid research and manufacturing.
It has recently been reported that reactions can occur faster in microdroplets than in extended condensed matter. The electric charge of droplets has also been suggested as a possible cause of this ...phenomenon. Here, we investigate the influence of electric charges on the photodegradation of single, optically trapped oleic acid aerosol droplets in the absence of other reactive species. The temporal evolution of the chemical composition and the size of droplets with charge states ranging from 0 to 104 elementary charges were retrieved from Raman spectra and elastic light scattering, respectively. No influence of the droplet charge was observed, either on the chemical composition or on the kinetics. Based on a kinetic multilayer model, we propose a reaction mechanism with the photoexcitation of oleic acid into an excited state, subsequent decay into intermediates and further photoexcitation of intermediates and their decay into nonvolatile and volatile products.
Abstract
GRB 221009A is a long gamma-ray burst among the most energetic and nearest (
z
= 0.151) detected so far. The energy fluence of the burst was so large to cause ionization of the upper layers ...of Earth’s atmosphere and also observable signals in satellite-borne particle detectors. Electron signals, with the same GRB time development, can arise from the interaction of energetic photons with the particle detector and support structures. This effect was previously reported for the HEPP-L on board the China Seismo-Electromagnetic Satellite. We searched for the same effect on the particle detectors on board five POES and MetOp satellites. Electron signals in coincidence with the gamma-ray emission of the burst were found in three satellites, which were well illuminated by the GRB. The properties of the found electron signals are reported and discussed.
The High-energy Particle Detector (HEPD) on board the China Seismo-Electromagnetic Satellite (CSES-01)-launched on 2018 February 2-is a light and compact payload suitable for measuring electrons ...(3-100 MeV), protons (30-250 MeV), and light nuclei (up to a few hundreds of MeV). The Sun-synchronous orbit and large acceptance allow HEPD to measure cosmic-ray particles near the 65° latitude limit for a fair amount of time per day. In this work, three semiannual galactic hydrogen energy spectra between ∼40 and 250 MeV are presented, including a comparison with theoretical spectra from HelMod, a 2D Monte Carlo model developed to simulate the solar modulation of cosmic rays throughout the heliosphere. To our knowledge, these are the first hydrogen energy spectra below 250 MeV measured at 1 au between 2018 and 2020.
Cellulose‐based artefacts are highly prone to degradation, especially in the presence of acidic compounds, which trigger the depolymerization of cellulose chains and lead to a loss in the original ...mechanical resistance of the material. Calcium hydroxide nanoparticles dispersed in organic solvent have been recently proposed for the deacidification of cellulose‐based artworks. In this work, changes induced on paper by a deacidification treatment, following an acidification bath, were studied by nuclear magnetic resonance (NMR) relaxometry and by the so‐called NMR diffraction of water trapped in the cellulose network. The deacidification treatment modifies intrachain and interchain bonds in hydrolyzed and degraded cellulose, leading to a buffered cellulose network configuration, which is similar to that characterizing the untreated reference sample in terms of relaxation parameters. Overall, calcium hydroxide nanoparticles are demonstrated effective in hindering the degradation of cellulose induced by acids and ageing in strong environmental conditions, even from the standpoint of cellulose network arrangement. It is worth noting, too, that the unilateral NMR device used for the relaxation measurements may represent a powerful tool for the preservation of cellulose‐based artworks because it allows for the monitoring of the conservation status of cellulose in a completely non‐invasive manner.
Two‐dimensional NMR relaxation and NMR diffraction are effective in tracking bond modifications in acidic/deacidified cellulose, proving an ideal noninvasive tool to assess the preservation of cellulose‐based artworks from degradation and ageing, even under strong environmental conditions, by application of calcium hydroxide nanoparticles.
Management of spontaneous pneumothorax (SP) is still subject to debate. Although encouraging results of recent studies about outpatient management with chest drains fitted with a one-way valve, no ...data exist concerning application of this strategy in real life conditions. We assessed how SP are managed in Emergency departments (EDs), in particular the role of outpatient management, the types of interventions and the specialty of the physicians who perform these interventions.
From June 2009 to May 2013, all cases of spontaneous primary (PSP) and spontaneous secondary pneumothorax (SSP) from EDs of 14 hospitals in France were retrospectively included. First line treatment (observation, aspiration, thoracic drainage or surgery), type of management (admitted, discharged to home directly from the ED, outpatient management) and the specialty of the physicians were collected from the medical files of the ED.
Among 1868 SP included, an outpatient management strategy was chosen in 179 PSP (10%) and 38 SSP (2%), mostly when no intervention was performed. Only 25 PSP (1%) were treated by aspiration and discharged to home after ED admission. Observation was the chosen strategy for 985 patients (53%). In 883 patients with an intervention (47%), it was performed by emergency physicians in 71% of cases and thoracic drainage was the most frequent choice (670 patients, 76%).
Our study showed the low level of implementation of outpatient management for PS in France. Despite encouraging results of studies concerning outpatient management, chest tube drainage and hospitalization remain preponderant in the treatment of SP.
The translational and orientational dynamics of water in carbon nanotubes has been studied by quasi-elastic neutron scattering from 300 down to 10 K. Results show that, reducing temperature below 200 ...K, part of this water behaves as a quasi-free rotor, that is, the orientational energy of such molecules becomes comparable to the rotational energy of water in the gas phase. This novel and unique dynamic behavior is related to the appearance of water molecules characterized by a coordination number of about two, which is promoted by sub-nanometer axial confinement. This peculiar molecular arrangement allows water to show an active rotational dynamics even at temperatures as low as 10 K. The translational mobility shows a behavior compatible with the rotational one.
The prominent degradation mechanism of cellulose is the acid-catalyzed hydrolysis of glycosidic bonds, which results in the decrease of the degree of polymerization (DP) and, macroscopically, in the ...dramatic decay of the mechanical resistance of cellulose-based materials. Alkaline nanoparticles in organic solvents have been recently proposed for the deacidification of cellulose-based artworks. Their effectiveness has been demonstrated in previous studies, by pH and DP measurements, colorimetric and thermal analyses. Herein, the changes in the cellulosic network following an acidification bath and a consequent deacidification treatment using Ca(OH)
2
nanoparticles, have been investigated by NMR self-diffusion dynamics of water and related to the changes of samples’ DPs. The deacidification treatment modifies intra- and inter-chain interactions, leading to a buffered cellulose network configuration similar to that characterizing the untreated reference sample in terms of diffusive parameters and confining environment. Such results are plausibly due to a rearrangement in connectivity of the cellulosic network, even though with a different physical fingerprint with respect to the reference sample. The analysis of tortuosity of the cellulosic network in acidic and deacidified samples confirms this conclusion, further corroborating the idea that calcium hydroxide nanoparticles are an effective tool to hamper the degradation of cellulose induced by acids and aging in strong environmental conditions, even from the standpoint of cellulose network arrangement.
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