A study of the accuracy of mobile technology for measuring urban noise pollution in large scale participatory sensing campaigns

The study reports on the relevancy and accuracy of using mobile phones in participatory noise pollution monitoring studies in an urban context. During one year, 60 participants used the same smartphone model to measure environmental noise at 28 different locations in Paris. All measurements were performed with the same calibrated application. The sound pressure level was recorded from the microphone every second during a 10-min period. The participants frequently measured the evolution of the sound level near two standard monitoring sound stations (in a square and near a boulevard), which enables the assessment of the accuracy and relevancy of collected acoustic measurements. The instantaneous A-weighting sound level, energy indicators such as L_A,eq, L_A10, L_A50 or L_A90 and event indicators such as the number of noise events exceeding a certain threshold L_α (NNEL ? L_α) were measured and compared with reference measurements. The results show that instantaneous sound levels measured with mobile phones correlate very well (r > 0.9, p < 0.05) with sound levels measured with a class 1 reference sound level meter with a root mean square error smaller than 3 dB(A). About 10% of the measurements for the boulevard location (respectively 20% for the square) were inaccurate (r < 0.3, p < 0.05). Nevertheless, mobile phone measurements are in agreement for the L_A50 and the L_A90 acoustic indicators with the fixed station (4-m high) measurements, with a median deviation smaller than 1.5 dB(A) for the boulevard (respectively 3 dB(A) for the square).     

A large‐solid‐angle X‐ray Raman scattering spectrometer at ID20 of the European Synchrotron Radiation Facility

An end‐station for X‐ray Raman scattering spectroscopy at beamline ID20 of the European Synchrotron Radiation Facility is described. This end‐station is dedicated to the study of shallow core electronic excitations using non‐resonant inelastic X‐ray scattering. The spectrometer has 72 spherically bent analyzer crystals arranged in six modular groups of 12 analyzer crystals each for a combined maximum flexibility and large solid angle of detection. Each of the six analyzer modules houses one pixelated area detector allowing for X‐ray Raman scattering based imaging and efficient separation of the desired signal from the sample and spurious scattering from the often used complicated sample environments. This new end‐station provides an unprecedented instrument for X‐ray Raman scattering, which is a spectroscopic tool of great interest for the study of low‐energy X‐ray absorption spectra in materials under in situ conditions, such as in operando batteries and fuel cells, in situ catalytic reactions, and extreme pressure and temperature conditions.     

Observational Aspects of Magnetic Reconnection at the Earth’s Magnetosphere

Magnetic field reconnection has shown to be the dominant process in the solar wind-Earth’s magnetosphere interaction. It enables mass, momentum, and energy exchange between different plasma regimes, and it is regarded as an efficient plasma acceleration and heating mechanism. Reconnection has been observed to occur in laboratory plasmas, at planetary magnetospheres in our Solar System, and the Sun. In this work, we focus on analyzing the characteristics of magnetic reconnection at the Earth’s magnetosphere according to spaceborne observations in the vicinity of our planet. Firstly, the locations where magnetic field reconnection are expected to occur within the vast magnetospheric region are addressed, and is shown how they are influenced by changes in the interplanetary magnetic field direction. The main magnetic field and plasma signatures of magnetic reconnection are discussed from both theoretical and observational points of view. Spacecraft observations of ion inertial length scale reconnection are also presented.     

Photolysis of polyphosphate ions in alkaline aqueous solution

Photolysis of pyrophosphate and tripolyphosphate ions in aqueous solution is proposed to produce electron detachment with formation of pyrophosphate and tripolyphosphate radicals (with quantum yields <0.1 at 266 nm), respectively. Formation of P₂O₇^·3− is observed after photolysis of both polyphosphate ions, because the decomposition of P₃O₁₀^·4− yields P₂O₇^·3−. The latter radicals further react with hydroxyl ions (k = 1.4 × 10⁶ M⁻¹s⁻¹) generating HO^· radicals. The reaction of the solvated electrons with molecular oxygen produces O₂^·−. The rate constants for the reaction of SO₄^·− radicals with P₂O₇⁴⁻ and P₃O₁₀⁵⁻ were also measured. © 2000 John Wiley & Sons, Inc. Int J Chem Kinet 32: 111–117, 2000     

Pressurized Hot Water Extraction and Bio-Hydrogels Formulation with Aristotelia chilensis [Mol.] Stuntz Leaves

Aristotelia chilensis is a plant rich in phenolics and other bioactive compounds. Their leaves are discarded as waste in the maqui berry industry. A new application of these wastes is intended by the recovery of bioactive compounds using pressurized hot water extraction with conventional or microwave heating. Both technologies have been selected for their green character regarding the type of solvent and the high efficiency in shorter operation times. Extractions were performed in the temperature range 140–200 °C with a solid/liquid ratio of 1:15 (w:w). The extracts’ total phenolic content, antioxidant capacity, and saccharides content obtained with both heating methods were measured. Additionally, the thermo-rheological properties of the gelling matrix enriched with these extracts were analyzed. Optimum conditions for lyophilized extracts were found with conventional heating, at 140 °C and 20 min extraction; 250.0 mg GAE/g dry extract and 1321.5 mg Trolox/g dry extract. Close to optimum performance was achieved with microwave heating in a fraction of the time (5 min) at 160 °C (extraction), yielding extracts with 231.9 mg GAE/g dry extract of total phenolics and antiradical capacity equivalent to 1176.3 mg Trolox/g dry extract. Slightly higher antioxidant values were identified for spray-dried extracts (between 5% for phenolic content and 2.5% for antioxidant capacity). The extracts obtained with both heating methods at 200 °C contained more than 20% oligosaccharides, primarily glucose. All the formulated gelling matrices enriched with the obtained extracts displayed intermediate gel strength properties. The tested technologies efficiently recovered highly active antioxidant extracts, rich in polyphenolics, and valuable for formulating gelling matrices with potential applicability in foods and other products.     

New Potential Pharmacological Targets of Plant-Derived Hydroxyanthraquinones from Rubia spp.

The increased use of polyphenols nowadays poses the need for identification of their new pharmacological targets. Recently, structure similarity-based virtual screening of DrugBank outlined pseudopurpurin, a hydroxyanthraquinone from Rubia cordifolia spp., as similar to gatifloxacin, a synthetic antibacterial agent. This suggested the bacterial DNA gyrase and DNA topoisomerase IV as potential pharmacological targets of pseudopurpurin. In this study, estimation of structural similarity to referent antibacterial agents and molecular docking in the DNA gyrase and DNA topoisomerase IV complexes were performed for a homologous series of four hydroxyanthraquinones. Estimation of shape- and chemical feature-based similarity with (S)-gatifloxacin, a DNA gyrase inhibitor, and (S)-levofloxacin, a DNA topoisomerase IV inhibitor, outlined pseudopurpurin and munjistin as the most similar structures. The docking simulations supported the hypothesis for a plausible antibacterial activity of hydroxyanthraquinones. The predicted docking poses were grouped into 13 binding modes based on spatial similarities in the active site. The simultaneous presence of 1-OH and 3-COOH substituents in the anthraquinone scaffold were emphasized as relevant features for the binding modes’ variability and ability of the compounds to strongly bind in the DNA-enzyme complexes. The results reveal new potential pharmacological targets of the studied polyphenols and help in their prioritization as drug candidates and dietary supplements.     

Disorder Effects in “Plastic” and Highly Conducting Compounds of Poly(aniline)

Numerical methods of molecular dynamics have been combined to measurements of X-ray and neutron scattering in order to obtain a realistic view of structural and dynamical disorder properties of conducting compounds of so called “plastdoped” poly(aniline)s. This combination allowed us to propose for the whole family of these compounds one generic model of a layered structure in which exist statistical fluctuations of the electronic density along the stacking direction of alternating molecular layers. The most part of the dynamics in the 10⁻¹³–10⁻⁹ s time range concerns the motions of protons borne by the flexible tails of doping counter-ions contained in the structure. We found that the molecular dynamics is characterized by both broad time and spatial distributions. These experimental facts coupled to those obtained with electrical conductivity measurements indicate that the high mobility of the counter-ion sublattice seems to be a prerequisite to promote a global metal like electronic behaviour of the polymer films.