Reliable, autonomous, internally self-powered microfluidic pumps are in critical demand for rapid point-of-care (POC) devices, integrated molecular-diagnostic platforms, and drug delivery systems. ...Here we report on a Self-powered Imbibing Microfluidic Pump by Liquid Encapsulation (SIMPLE), which is disposable, autonomous, easy to use and fabricate, robust, and cost efficient, as a solution for self-powered microfluidic POC devices. The imbibition pump introduces the working liquid which is sucked into a porous material (paper) upon activation. The suction of the working liquid creates a reduced pressure in the analytical channel and induces the sequential sample flow into the microfluidic circuits. It requires no external power or control and can be simply activated by a fingertip press. The flow rate can be programmed by defining the shape of utilized porous material: by using three different paper shapes with circular section angles 20°, 40° and 60°, three different volume flow rates of 0.07 μL s(-1), 0.12 μL s(-1) and 0.17 μL s(-1) are demonstrated at 200 μm × 600 μm channel cross-section. We established the SIMPLE pumping of 17 μL of sample; however, the sample volume can be increased to several hundreds of μL. To demonstrate the design, fabrication, and characterization of SIMPLE, we used a simple, robust and cheap foil-laminating fabrication technique. The SIMPLE can be integrated into hydrophilic or hydrophobic materials-based microfluidic POC devices. Since it is also applicable to large-scale manufacturing processes, we anticipate that a new chapter of a cost effective, disposable, autonomous POC diagnostic chip is addressed with this technical innovation.
Small-scale facilities play a significant role in the landscape of nuclear physics research in Europe. They address a wide range of fundamental questions and are essential for teaching and training ...personnel in accelerator technology and science, providing them with diverse skill sets, complementary to large projects. The current status and perspectives of nuclear physics research at small-scale facilities in Europe will be given.
Human hair absorbs numerous biomolecules from the body during its growth. This can act as a fingerprint to determine substance intake of an individual, which can be useful in forensic studies. The ...cocaine concentration profile along the growth axis of hair indicates the time evolution of the metabolic incorporation of cocaine usage. It could be either assessed by chemical extraction and further analysis of hair bundels, or by direct single hair fibre analysis with mass spectroscopy imaging (MSI). Within this work, we analyzed the cocaine distribution in individual hair samples using MeV-SIMS. Unlike conventional surface analysis methods, we demonstrate high yields of nonfragmented molecular ions from the surface of biological materials, resulting in high chemical sensitivity and non-destructive characterisation. Hair samples were prepared by longitudinally cutting along the axis of growth, leaving half-cylindrical shape to access the interior structure of the hair by the probing ion beam, and attached to the silicon wafer. A focused 5.8 MeV 35Cl6+ beam was scanned across the intact, chemically pristine hair structure. A non-fragmented protonated M+ H+ cocaine molecular peak at m/z = 304 was detected and localized along the cross-section of the hair. Its intensity exhibits strong fluctuations along the direction of the hair's growth, with pronounced peaks as narrow as 50 micrometres, corresponding to a metabolic incorporation time of approx. three hours.
MeV-SIMS is an emerging mass spectrometry imaging method, which utilizes fast, heavy ions to desorb secondary molecules. High yields and low fragmentation rates of large molecules, associated with ...the electronic sputtering process, make it particularly useful in biomedical research, where insight into distribution of organic molecules is needed. Since the implementation of MeV-SIMS in to the micro-beam line at the tandem accelerator of Jožef Stefan Institute, MeV-SIMS provided some valuable observations on the distribution of biomolecules in plant tissue, as discussed by Jenčič et al. (Nucl. Inst. Methods Phys. Res. B.
371
, 205–210,
2016
; Nucl. Inst. Methods Phys. Res. B.
404
, 140–145, 2017). However, limited focusing ability of the chlorine ion beam only allowed imaging at the tissue level. In order to surpass shortcomings of the existing method, we introduced a new approach, where we employ a continuous, low-current primary beam. In this mode, we bombard thin samples with a steady chlorine ion flux of approx. 5000 ions/s. After desorbing molecules, chlorine ions penetrate through the thinly cut sample and trigger the time-of-flight “start” signal on a continuous electron multiplier detector, positioned behind the sample. Such bombardment is more effective than previously used pulsing-beam mode, which demanded several orders of magnitude higher primary ion beam currents. Sub-micrometer focusing of low-current primary ion beam allows imaging of biological tissue on a subcellular scale. Simultaneously, new time-of-flight acquisition approach also improves mass resolution by a factor of 5. Within the article, we compare the performance of both methods and demonstrate the application of continuous mode on biological tissue. We also describe the thin sample preparation protocol, necessary for measurements with low primary ion currents.
.
The cross section for the
2
H(p,
γ
)
3
He reaction was measured in the energy range
E
= 47–210 keV, relevant for primordial nucleosynthesis. A proton beam was incident on two deuterated titanium ...targets. The angular distribution of emitted
γ
-rays was determined using two HPGe detectors, placed at
90
∘
and
135
∘
with respect to the incident beam direction. Results were compared with the latest
ab initio
theoretical calculation, including one- and many-body contributions. The predicted cross section and astrophysical S-factor are found to be in a very good agreement with measured values.
Secondary ion mass spectrometry (SIMS), based on primary ions within the MeV energy domain, also known as MeV-SIMS, is a subject of increasing scientific interest. The main drive for the interest in ...the development of MeV-SIMS is the ability to desorb high yields of large non-fragmented organic molecular ions from the sample surface. This makes MeV-SIMS particulary useful in imaging of biological tissues.
Imaging methods based on scanning a focused primary ion beam are associated with demanding focusing of the heavy energetic ions. As an alternative, stigmatic imaging mode has been studied here, applying point-to-point imaging characteristics of secondary ions in the linear Time-Of-Flight mass spectrometer. In stigmatic imaging approaches, spatial resolution is independent of the focussed spot size of the ionising primary ion beam, but instead dependant on the ability of the ion optics to project an image of the ion distributions removed from the surface onto a position sensitive ion detector.
A compact portable aerosol sampling and measurement device was developed at Jožef Stefan Institute (JSI). A CeBr3 scintillation detector is positioned centrally within a concertinaed filter assembly. ...It provides continuous and via network communications on-line monitoring of low levels of airborne radioactive particulates. The evaluation of the response of the device to the natural background at controlled conditions with elevated radon concentrations, performed at the National Institute of Ionizing Radiation Metrology of ENEA, is presented.
•Portable monitoring air pump for radioactive aerosols (MARE) was developed at JSI.•MARE incorporates CeBr3 detector, concertinaed filter and high flow rate air pump.•Calibration of MARE device with filters, spiked with CRM, was performed at NPL.•Tests performed in the environment with elevated radon concentrations at ENEA.
For nucleosynthesis calculations, precise reaction rates should be known at energies within the Gamow window. At these energies, electron screening cannot be neglected. Despite the significance of ...the effect, a huge disagreement between experimental data and theoretical predictions is still not understood. In order to address to this problem, we investigated the dependence of the electron screening potential on the target host lattice structure by measuring the rate of the
2
H(
19
F,p)
20
F reaction in zirconium, titanium and palladium targets containing deuterium.
In the frame of the European metrological research project MetroERM, a compact portable aerosol sampling and measurement device was developed at Jožef Stefan Institute. The system incorporates a ...CeBr3 scintillation detector positioned centrally within a concertinaed filter assembly and an improved high flow rate air pump. It provides continuous on-line low level airborne radioactive particulate monitoring for field station use via 3G network communications. The calibration of the device was performed at National Physical Laboratory (NPL) with filters, spiked with a certified mixed nuclide solution. Additionally first tests were performed in an environment with an elevated radon concentration.
•A compact portable aerosol sampling device was developed at Jožef Stefan Institute.•The system incorporates a CeBr3 scintillation detector positioned centrally within a filter assembly and high flow rate air pump.•The calibration of the device with filters, contaminated with CRM was performed at National Physical Laboratory.•First tests were performed in the environment with elevated radon concentrations.
The pile-up rejection in nuclear spectroscopy has been confronted recently by several pile-up correction schemes that compensate for distortions of the signal and subsequent energy spectra artifacts ...as the counting rate increases. We study here a real-time capability of the event-by-event correction method, which at the core translates to solving many sets of linear equations. Tight time limits and constrained front-end electronics resources make well-known direct solvers inappropriate. We propose a novel approach based on the Gauss-Seidel iterative method, which turns out to be a stable and cost-efficient solution to improve spectroscopic resolution in the front-end electronics. We show the method convergence properties for a class of matrices that emerge in calorimetric processing of scintillation detector signals and demonstrate the ability of the method to support the relevant resolutions. The sole iteration-based error component can be brought below the sliding window induced errors in a reasonable number of iteration steps, thus allowing real-time operation. An area-efficient hardware implementation is proposed that fully utilizes the method's inherent parallelism.
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