On the challenges of detecting whole Staphylococcus aureus cells with biosensors

International audienc

On the mechanism of synthesis of PbTiO3 thin films by thermal annealing of Pb/Ti layers in air at atmospheric pressure

Single phase PbTiO3 thin films were synthesized by thermal treatment at temperatures 350–700 °C of Pb/Ti magnetron sputtered layered structures at atmospheric pressure in air. The film stoichiometry was accurately controlled by deposition of individual layers with the required thickness. Scanning electron microscopy views showed that initially smooth surfaces had porous and granular structure after thermal annealing. Surface morphology depends on the substrate material and the cooling rate. X-Ray diffraction patterns revealed the nanometric microstructure of synthesized films. The size of crystallites in oxidized films depends on the annealing temperature and does not depend on the annealing time. The atomic mixing and oxidation kinetics are discussed and applied to PbTiO3. The emphasis is made on the analysis of surface atom relocation and restructuring processes under reactive adsorption at elevated temperatures and their role in the formation of surface instabilities and initiation of transport of oxygen from the surface into the bulk directed to stabilize these instabilities. The experimental results support that the formation of PbTiO3 films homogeneous in structure and composition during the thermal oxidation is a result of intensive mixing of Pb/Ti layers with continuous supply of oxygen though the surface. Under non-equilibrium conditions on the surface, the oxygen atoms are driven into grain boundaries of crystallites, result in high compressive stress inducing fragmentation of grains and their oxidation by oxygen diffusion through boundaries into the nanograins. The oxidation kinetics and the size of crystallites is governed by the mass-transport processesGamtos mokslų fakultetasKauno technologijos universitetasLietuvos energetikos institutasVytauto Didžiojo universiteta

Biochips for Direct Detection and Identification of Bacteria in Blood Culture-Like Conditions

Abstract Bloodstream bacterial infections are life-threatening conditions necessitating prompt medical care. Rapid pathogen identification is essential for early setting of the best anti-infectious therapy. However, the bacterial load in blood samples from patients with bacteremia is too low and under the limit of detection of most methods for direct identification of bacteria. Therefore, a preliminary step enabling the bacterial multiplication is required. To do so, blood cultures still remain the gold standard before bacteremia diagnosis. Bacterial identification is then usually obtained within 24 to 48 hours -at least- after blood sampling. In the present work, the fast and direct identification of bacteria present in blood cultures is completed in less than 12 hours, during bacterial growth, using an antibody microarray coupled to a Surface Plasmon Resonance imager (SPRi). Less than one bacterium (Salmonella enterica serovar Enteritidis) per milliliter of blood sample is successfully detected and identified in blood volumes similar to blood tests collected in clinics (i.e. several milliliters). This proof of concept demonstrates the workability of our method for human samples, despite the highly complex intrinsic nature of unprocessed blood. Our label-free method then opens new perspectives for direct and faster bacterial identification in a larger range of clinical samples

Description of supportive care and feasibility of physical exercise program to improve quality of life in advanced melanoma patients.

Physical activity is the first-line treatment of cancer-related fatigue. It has shown benefits on patient's quality of life (QoL) when practiced during and after treatment. New treatments have drastically changed the prognosis of melanoma. Still, few data are available about research program of supportive care in advanced melanoma. The primary outcome was to assess the feasibility of setting up a prospective study evaluating the benefits of Adapted Physical Activity (APA) on the QoL of patients with advanced melanoma. Feasibility was defined with a combination of five criteria including completion of questionnaire, recruitment, participant retention, patient adhesion to supportive care, and absence of adverse event. Between September 2019 and March 2021, 271 melanoma patients were questioned. Around 60% of stage IV melanoma patients were interested in support care. Patient retention at 3 months was sufficient. Only one patient could not be evaluated after 3 months of enrolment because of deterioration of the general state. Adhesion to exercise and sessions was good. Supervised APA program appeared to be safe and well tolerated as no adverse events or discontinuations were reported. Setting up a prospective research program evaluating the benefits of physical activity in advanced melanoma patients seems feasible. With melanoma becoming a chronic disease, supportive care may reduce fatigue, improve QoL and help maintain a healthy lifestyle. Data supporting its benefits on this survivor population are needed

Ion beam amorphization of muscovite mica

The microstructure of a muscovite mica exposed to a rare gas ion beam has been studied by transmission electron microscopy. The investigation of damage without implantation was carried out using argon and helium ions of sufficient energy to traverse the 100–150 nm mica specimens. For 340 keV Ar++ irradiation, amorphization of mica occurred at a fluence as low as 3.5 × 1014 ions · cm−2, which corresponds to 0.29 dpa. Muscovite can be amorphized using 80 keV helium ions, but this requires a much higher fluence and damage production of 4.6 × 10−6 ions · cm−2 and 0.60 dpa, respectively. Since helium irradiation results principally in ionization energy loss, it indicates that amorphization of muscovite results mainly from nuclear interactions. Complete amorphization of muscovite mica is found to take place for all ions at approximately the same amount of nuclear energy transfer to energetic primary knock-on atoms, assuming a recoil energy greater than 500 eV. This suggests that amorphization occurs directly in dense displacement cascades. A significant amount of helium, 100 ppm, can be implanted into muscovite mica without destroying the crystal structure