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Urea detection in phosphate buffer and artificial urine
No full textA simplified kinetic model for the quantitative analysis of a potentiometric, pH-based
urea biosensor is presented. The device was an electrolyte–insulator–semiconductor ca-
pacitor (EISCAP) with a pH-sensitive Ta2O5 gate functionalized by a polyallylamine hy-
drochloride (PAH)/urease bilayer. Within the steady-state approximation, the kinetic
equations yielded an implicit algebraic relation linking the bulk urea concentration to the
local pH at the sensor surface. Numerical solution of this equation, combined with a fitting
routine, provides the apparent Michaelis–Menten constant (K ) and the normalized max-
imum reaction rate (k ). Validation against the literature data confirmed the reliability of
the approach. Experimental results were then analyzed in both phosphate buffer (PBS)
and artificial urine (AU), covering urea concentrations of 0.1–50 mM. The fitted parame-
ters showed comparable K values of 10.9 mM (PBS) and 32.4 mM (AU), but strongly
different k values: 2.2 10 (PBS) versus 8.6 10 (AU). The three-order reduc-
tion in AU was attributed to the inhibitory effects inherent to complex biological fluids.
These findings highlight the importance of the model-based quantitative analysis of
EISCAP biosensors, enabling the accurate characterization of immobilized enzyme layers
and guiding optimization for applications in realistic sample matrices
Ali ima trta rada vodo? Koliko in kdaj najbolj?
No full textWater is essential for life, but grapevines can survive under water stress conditions improving the quality of the wines. Water stress can be measured with simple tools, such as Scholander camera, and at pre-dawn we could estimate its availability in the soil, while at midday the evaporative demand of the atmosphere. During growing season, early water stress is particularly effective since adaptation mechanisms are adopted by grapevines increasing their resilience to drought. Among them, root growth can be significantly impacted by season course, but on the other hand complicates the assessment of vineyard water balance and thus irrigation requirements. The lecture will combine basic knowledge on water dynamics, physiological aspects, remote sensing tools, and the opportunity to adopt decision support systems to create different scenarios of water deficit together with their implications on grape and wine quality
Quasi-constant time gap in multiple rings of elves
No full textWe present evidence that the time delay between the multiple rings of elves is not caused by the ground reflection of the electromagnetic pulse produced by intracloud lightning. To investigate temporal differences of multi‐elves, we analyzed data from four storms occurring at various times and distances from the Pierre Auger Observatory in Malargüe, Argentina. The Auger fluorescence detector\u27s high temporal resolution of 100 ns enabled the frequent observation of multi‐elves, accounting for approximately 23% of the events. By examining the traces of 70 double and 24 triple elves, we demonstrate that the time delay between the rings remains relatively constant regardless of the arc distance to the lightning. These results deviate from the trend expected from the electromagnetic pulse (EMP) ground reflection model, which predicts a decreasing time delay with increasing arc distance from an intracloud lightning at a given height. The first emission ring is due to a direct path of the EMP to the ionosphere, with the reflected EMP creating the second ring. Simulations conducted with this model demonstrate that short energetic in‐cloud pulses can generate four‐peak elves, and a temporal resolution of at least 25 s is required to separate them. Therefore, temporal resolution is crucial in the study of multi‐elves. Our observations in the Córdoba province, central Argentina, indicate that the current understanding of the mechanism generating these phenomena may be incomplete, and further studies are needed to assess whether multi‐elves are more likely related to the waveform shape of the lightning than to its altitude
An integrative structural biology approach to identify the binding mode of a nanobody towards the pea ascorbate peroxidase
No full text
A multipurpose setup for ultrafast XUV spectroscopies
No full textA tabletop setup for ultrafast x-ray ultraviolet (XUV) magnetic scattering and molecular spectroscopy has been developed at the Laboratory of Quantum Optics at the University of Nova Gorica. This system provides XUV light in a spectral range allowing the study of M-absorption edges in pure transition metals and their alloys, with a pulse duration of 35 fs and a repetition rate of 5 kHz. The experimental setup is optimized for pump–probe XUV magneto-optics, with element selectivity. In addition, the chamber can operate to acquire harmonic spectra generated by selected molecular gases, enabling the investigation of strong-field photoinduced electron dynamics. This paper presents an overview of the setup, along with the results of demonstration experiments