CLINICAL AND MICROBIOLOGICAL SUBSTANTIATION OF TOPICAL APPLICATION OF SORPTION HYDROPHILIC/HYDROPHOBIC COMPOSITION BASED ON NANOSILICA IN THE TREATMENT OF PATIENTS WITH BURNS

Relevance.One of the promising methods of treatment of patients with burns is the local use of sorption agents with antimicrobial properties. Objective: experimental study of antimicrobial properties and clinical evaluation of the effectiveness of local use of a new sorption composition based on nanosilica in the complex treatment of patients with burns. Materials and methods. The suggested sorption nanocomposition included highly dispersed silicon dioxide, polymethylsiloxane, decamethoxine, metronidazole. The experimental study involved the study of the antimicrobial properties of the sorption nanocomposition and antimicrobial agents which are part of it. The clinical material consisted of the results of examination of 42 patients with IIab-III degree burns with an area of 10-30% of the body surface. Depending on the tactics of local treatment, patients were divided into 2 groups: after early necrectomy, xenodermoplasty, the wound surface of the patients in the main group (n = 20) was treated with a solution of decamethoxine in combination with the same sorption powder. Treatment in the comparison group (n = 22) was similar except the use of sorption drugs. The examination included visual inspection of the injured area in combination with microbiological monitoring of the wound contents on the 3rd,7th,14th day. Results. The obtained results confirmed the sufficient antimicrobial potential of the studied sorption nanocomposition, the properties of which are not inferior to the existing antiseptics for museum and clinical strains of microorganisms and fungi. Signs of a more favorable wound healing process of the patients in the main group were observed: faster wound cleaning, less inflammatory reactions and much shorter preparation of wounds for grafting. Conclusions. The obtained results convincingly indicate the effectiveness of a multicomponent composite based on nanosilica with antimicrobial components in a comprehensive treatment of patients with burns

Observation of the Second Triatomic Resonance in Efimov’s Scenario

We report the observation of a three-body recombination resonance in an ultracold gas of cesium atoms at a very large negative value of the s-wave scattering length. The resonance is identified as the second triatomic Efimov resonance, which corresponds to the situation where the first excited Efimov state appears at the threshold of three free atoms. This observation, together with a finite-temperature analysis and the known first resonance, allows the most accurate demonstration to date of the discrete scaling behavior at the heart of Efimov physics. For the system of three identical bosons, we obtain a scaling factor of 21.0(1.3), close to the ideal value of 22.7

Interleaved Atom Interferometry for High Sensitivity Inertial Measurements

Cold-atom inertial sensors target several applications in navigation, geoscience and tests of fundamental physics. Reaching high sampling rates and high inertial sensitivities, obtained with long interrogation times, represents a challenge for these applications. We report on the interleaved operation of a cold-atom gyroscope, where 3 atomic clouds are interrogated simultaneously in an atom interferometer featuring a 3.75 Hz sampling rate and an interrogation time of 801 ms. Interleaving improves the inertial sensitivity by efficiently averaging vibration noise, and allows us to perform dynamic rotation measurements in a so-far unexplored range. We demonstrate a stability of $3\times 10^{-10}$ rad.s$^{-1}$, which competes with the best stability levels obtained with fiber-optics gyroscopes. Our work validates interleaving as a key concept for future atom-interferometry sensors probing time-varying signals, as in on-board navigation and gravity-gradiometry, searches for dark matter, or gravitational wave detection

Accurate trajectory alignment in cold-atom interferometers with separated laser beams

International audienceCold-atom interferometers commonly face systematic effects originating from the coupling between the trajectory of the atomic wave packet and the wavefront of the laser beams driving the interferometer. Detrimental for the accuracy and the stability of such inertial sensors, these systematics are particularly enhanced in architectures based on spatially separated laser beams. Here we analyze the effect of a coupling between the relative alignment of two separated laser beams and the trajectory of the atomic wave packet in a four-light-pulse cold-atom gyroscope operated in fountain configuration. We present a method to align the two laser beams at the 0.2μrad level and to determine the optimal mean velocity of the atomic wave packet with an accuracy of 0.2mms−1. Such fine tuning constrains the associated gyroscope bias to a level of 1×10−10rads−1. In addition, we reveal this coupling using the point-source interferometry technique by analyzing single-shot time-of-flight fluorescence traces, which allows us to measure large angular misalignments between the interrogation beams. The alignment method which we present here can be employed in other sensor configurations and is particularly relevant to emerging gravitational wave detector concepts based on cold-atom interferometry

Testing the Sagnac effect with a two-axis cold atom gyroscope

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Atom Interferometry with Top-Hat Laser Beams

International audienceThe uniformity of the intensity and the phase of laser beams is crucial to high-performance atom interferometers. Inhomogeneities in the laser intensity profile cause contrast reductions and systematic effects in interferometers operated with atom sources at micro-Kelvin temperatures and detrimental diffraction phase shifts in interferometers using large momentum transfer beam splitters. We report on the implementation of a so-called top-hat laser beam in a long-interrogation-time cold-atom interferometer to overcome the issue of inhomogeneous laser intensity encountered when using Gaussian laser beams. We characterize the intensity and relative phase profiles of the top-hat beam and demonstrate its gain in atom-optic efficiency over a Gaussian beam, in agreement with numerical simulations. We discuss the application of top-hat beams to improve the performance of different architectures of atom interferometers