Microwave dielectric heating of non-aqueous droplets in a microfluidic device for nanoparticle synthesis

We describe a microfluidic device with an integrated microwave heater specifically designed to dielectrically heat non-aqueous droplets using time-varying electrical fields with the frequency range between 700 and 900 MHz. The precise control of frequency, power, temperature and duration of the applied field opens up new vistas for experiments not attainable by conventional microwave heating. We use a non-contact temperature measurement system based on fluorescence to directly determine the temperature inside a single droplet. The maximum temperature achieved of the droplets is 50 °C in 15 ms which represents an increase of about 25 °C above the base temperature of the continuous phase. In addition we use an infrared camera to monitor the thermal characteristics of the device allowing us to ensure that heating is exclusively due to the dielectric heating and not due to other effects like non-dielectric losses due to electrode or contact imperfection. This is crucial for illustrating the potential of dielectric heating of benzyl alcohol droplets for the synthesis of metal oxides. We demonstrate the utility of this technology for metal oxide nanoparticle synthesis, achieving crystallization of tungsten oxide nanoparticles and remarkable microstructure, with a reaction time of 64 ms, a substantial improvement over conventional heating methods.Engineering and Applied SciencesPhysic

Scope of diagnosis of the state of patients with cardiovascular diseases for the needs of nursing care

Wstęp. Choroby sercowo-naczyniowe są głównym zagrożeniem zdrowia i życia dorosłych Polaków. Udział pielęgniarek w rozpoznawaniu i w rozwiązywaniu problemów opieki tej grupy pacjentów w ramach profilaktyki wtórnej jest istotnym ogniwem profesjonalnej strategii pomocy.Cel. Celem pracy było określenie stanów i problemów opiekuńczych pacjentów z chorobami układu krążenia stanowiących podstawę do postawienia diagnozy pielęgniarskiej.Materiał i metody. Badaniami objęto 120 pacjentów ze schorzeniami układu krążenia zgłaszających się do przychodni POZ. Zastosowano metodę sondażu diagnostycznego z autorsko opracowanym kwestionariuszem ankiety.Wyniki. Wśród badanych 51% stanowiły kobiety, a 49% mężczyźni. Według BMI u 47% ankietowanych wystąpiła nadwaga, a 39% osób miało otyłość. Najczęściej występującymi schorzeniami układu krążenia u badanych były: nadciśnienie tętnicze (87%), niewydolność serca (42%) oraz choroba wieńcowa (42%). Respondenci podali, że mierzą ciśnienie tętnicze kilka razy w tygodniu (36%). Prawie 3/4 pacjentów posiadało wiedzę, że czynniki ryzyka chorób sercowo-naczyniowych można zminimalizować, lecz nie podejmowało aktywnych działań w tym zakresie. Chęć zmiany swojego dotychczasowego stylu życia wyrażało 56% badanych.Wnioski. W grupie pacjentów z chorobami układu krążenia występowała nadwaga i otyłość, która istotnie częściej dotyczyła mężczyzn niż kobiet. Pacjenci deklarowali przeżywanie stresu w miejscu pracy i życiu rodzinnym głównie na poziomie średnim. Najczęstszymi problemami do postawienia diagnozy pielęgniarskiej były: nietolerancja aktywności fizycznej, duszność pochodzenia sercowego, omdlenia z utratą przytomności, bóle w klatce piersiowej.Introduction. Cardiovascular diseases create major risk for the health and life of adult Poles. The participation of nurses in diagnosing and solving problems of care in this group of patients within secondary prophylaxis is an important element of professional care strategy.Aim. Determination of states and care problems of patients with cardiovascular diseases as a basis for making nursing diagnosis.Material and methods. The study included 120 patients with cardiovascular diseases who reported to the PHC Outpatient Department, and was conducted by the method of a diagnostic survey with a questionnaire designed by the author.Results. As many as 51% of respondents were females, and 49% males. According to the BMI, 47% of respondents were overweight, and 39% obese. The most frequent cardiovascular disorders were: arterial hypertension (87%), followed by heart failure (42%), and coronary heart disease (42%). As many as 36% of respondents reported that they measured arterial blood pressure several times a week. Nearly 3/4 of patients possessed knowledge concerning the possibility to reduce cardiovascular risk factors; however, they did not undertake active actions in this respect, whereas 56% of patients wished to change their to-date life style.Conclusions. In the group of patients with cardiovascular diseases, overweight and obesity occurred frequently, more often in men than women. The patients declared that they experienced stress at their place of work and in family life, mainly on an average level. Intolerance of physical activity, cardiac dyspnea, syncope with loss of consciousness, chest pain, were the most often symptoms for making nursing diagnosis

Spectroscopy and scattering for chemistry:new possibilities and challenges with large scale facilities

Kirsten M. o. Jensen, Dorota Koziej and Serena DeBeer introduce theNanoscalethemed issue on spectroscopy and scattering for chemistry: new possibilities and challenges with large scale facilities

Hard X-ray Photon-in Photon-out Spectroscopy as a Probe of the Temperature-Induced Delocalization of Electrons in Nanoscale Semiconductors

Hard X-ray photon-in photon-out spectroscopy has so far mainly been applied to investigate fundamental physical phenomena in superconductors and chemical reactivity of bioinorganic, photocatalytic, and catalytic materials. Here, we show, with the example of Pr6O11 nanoparticles, an n-type semiconductor, how high-energy resolution fluorescence detected (HERFD) X-ray absorption near edge structure (XANES) can be used to track the changes of partially filled f-bands. We observe a reversible variation of the spectral features related to the tetravalent Pr ions upon heating and cooling, whereas structural and chemical transformations can be excluded. We assign these changes to the occupancy of the O 2p–Pr 4f band and show that they directly relate to changes in the electrical conductance. Our results demonstrate how HERFD-XANES can be used to particularly study in situ the electronic properties of f-electrons in a semiconductor and how this method can be further extended to other classes of semiconducting nanomaterials.ISSN:0897-475

Lightweight, Room-Temperature CO2 Gas Sensor Based on Rare-Earth Metal-Free Composites- An Impedance Study

We report a light, flexible, and low-power poly(ionic liquid)/alumina composite CO2 sensor. We monitor the direct-current resistance changes as a function of CO2 concentration and relative humidity and demonstrate fast and reversible sensing kinetics. Moreover, on the basis of the alternating-current impedance measurements we propose a sensing mechanism related to proton conduction and gas diffusion. The findings presented herein will promote the development of organic/ inorganic composite CO2 gas sensors. In the future, such sensors will be useful for numerous practical applications ranging from indoor air quality control to the monitoring of manufacturing processes

Selective magnetometry of superparamagnetic iron oxide nanoparticles in liquids

International audienceWe show that the properties of superparamagnetic iron oxide nanoparticles suspended in liquids can be effectively studied using Magnetic Circular Dichroism in Resonant Inelastic X-ray Scattering. Analysis of the spectral shape and magnetic contrast produced by this experiment enables an assessment of the site distribution and magnetic state of metal ions in the spinel phase. The selective magnetization profile of particles as derived from the field dependence of dichroism empowers an estimation of particle size distribution. Furthermore, the new proposed methodology discriminates sizes that are below the detection limits of X-ray and light scattering probes and that are difficult to spot in TEM