Detecting Iron Oxidation States in Liquids with the VOXES Bragg Spectrometer

Determining the oxidation states of metals assumes great importance in various applications because a variation in the oxidation number can drastically influence the material properties. As an example, this becomes evident in edible liquids like wine and oil, where a change in the oxidation states of the contained metals can significantly modify both the overall quality and taste. To this end, here we present the MITIQO project, which aims to identify oxidation states of metals in edible liquids utilizing X-ray emission with Bragg spectroscopy. This is achieved using the VOXES crystal spectrometer, developed at INFN National Laboratories of Frascati (LNF), employing mosaic crystal (HAPG) in the Von Hamos configuration. This combination allow us to work with effective source sizes of up to a few millimeters and improves the typical low efficiency of Bragg spectroscopy, a crucial aspect when studying liquids with low metal concentration. Here we showcase the concept behind MITIQO, for a liquid solution containing oxidized iron. We performed several high-resolution emission spectra measurements, for the liquid and for different powdered samples containing oxidized and pure iron. By looking at the spectral features of the iron's K$\beta$ emission lineshape, we were able to obtain, for a liquid, a result consistent with the oxidized iron powders and successfully quantifying the effect of oxidation

Hyperalgesia and laser evoked potentials alterations in hemiparkinson: Evidence for an abnormal nociceptive processing

a number of patients with parkinson's disease (PD) complain of painful sensations that might be related not only to peripheral factors (muscle spasms, postural abnormalities) but also to an abnormal processing of nociceptive inputs in the central nervous system (CNS).To test this hypothesis, we recorded scalp CO2 laser evoked potentials (LEPs) to foot skin stimulation in 11 pain-free treated PD patients affected by hemiparkinson (during the off state), in 6 pain-free drug-naive hemiparkinsonian patients and in 11 healthy subjects. after each LEP recording, both patients and controls were asked to rate pain due to laser stimuli.In all subjects, CO2 laser stimulation gave rise to a main negative N2 potential followed by a positive P2 response at vertex peaking at a latency of about 250 and 350 ms respectively which are thought to originate from several brain structures devoted to nociceptive input processing, including the cingulate gyrus and insula.ANOVA showed that the N2/P2 amplitude was significantly lower and pain rating significantly increased in treated PD patients than in controls in both the affected and unaffected sides, while in drug-naive PD patients the reduction of the N2/P2 amplitude and the increase in pain rating were observed only in the affected side. these results suggest that in pain-free PD patients there is an abnormal nociceptive input processing that may be independent of the clinical expression of parkinsonian motor signs

Seeing the pain of others while being in pain: A laser-evoked potentials study

Seeing actions, emotions and feelings of other individuals may activate resonant mechanisms that allow the empathic understanding of others' states. Being crucial for implementing pro-social behaviors, empathy is considered as inherently altruistic. Here we explored whether the personal experience of pain make individuals less inclined to share others' pain. We used laser-evoked potentials (LEPs) to explore whether observation of painful or non-noxious stimuli delivered to a stranger model induced any modulation in the pain system of onlookers who were suffering from pain induced by the laser stimuli. After LEPs recording, participants rated intensity and unpleasantness of the laser pain, and of the pain induced by the movie in themselves and in the model. Mere observation of needles penetrating the model's hand brought about a specific reduction of the N1/P1 LEP component, related to the activation of somatic nodes of the pain matrix. Such reduction is stronger in onlookers who rated the pain intensity induced by the pain movie as higher in themselves and lower in the model. Conversely, the N2a-P2 component, supposedly associated to affective pain qualities, did not show any specific modulation during observation of others' pain. Thus, viewing `flesh and bone' pain in others specifically modulates neural activity in the pain matrix sensory node. Moreover, this socially-derived inhibitory effect is correlated with the intensity of the pain attributed to self rather than to others suggesting that being in pain may bias the empathic relation with stranger models towards self-centred instead than other-related stances. (c) 2008 Elsevier Inc. All rights reserved

Distraction affects frontal alpha rhythms related to expectancy of pain:an EEG study

previous electroencephalographic (EEG) evidence has shown event-related desynchronization (ERD) of alpha rhythms before predictable painful stimuli, as a possible neural concomitant of attentional preparatory processes (babiloni, c., brancucci, a., babiloni, f., capotosto, p., carducci,f, cincotti, f., arendt-nielsen, l., chen, a.c., rossini, P.M., 2003. anticipatory cortical responses during the expectancy of a predictable painful stimulation. a high-resolution electroencephalography study. eur. j. neurosci. 18 (6) 1692-700). this study tested the hypothesis that alpha ERD before predictable painful stimuli is reduced as an effect of distraction. a visual warning stimulus preceded a laser painful stimulation, which was strictly followed by visual imperative stimuli. In the pain (control) condition, no task was required after the imperative stimuli. In the pain + movement condition, subjects had to perform a movement of the right index finger. In the pain + cognition condition, they had to mentally perform an arithmetical task. EEG data were recorded in 10 subjects from 30 electrodes. artifact-free recordings were spatially enhanced by surface Laplacian transformation. alpha ERD was computed at three alpha sub-bands according to subjects' individual alpha frequency peak (i.e., about 6-8 Hz, 8-10 Hz, 10-12 Hz). compared to the control condition, the subjects reported a significantly lower stimulus intensity perception and unpleasantness in the pain + movement and pain + cognition conditions. In addition, there was a cancellation of the alpha 3 ERD (i.e., about 10-12 Hz) in pain + cognition condition and even a generation of a statistically significant alpha 3 ERS in pain + movement condition. these effects were maximum over fronto-central midline. these results suggest that distraction during the expectancy of pain is related to a reduced neural desynchronization of fronto-central midline alpha rhythms (i.e., reduced cortical activation) towards an overt hyper-synchronization (cortical idling)

Habituation to pain in "Medication Overuse Headache":A CO(2) laser-evoked potential study

Objective.-Our aim was to investigate CO2 laser-evoked potential (LEP) habituation to experimental pain in a group of patients affected by medication-overuse headache, with a history of episodic migraine becoming chronic, before and after treatment, consisting in acute medication withdrawal and a preventive treatment cycle.Background.-One of the main features of LEPs in migraineurs is a lower habituation to repetitive noxious stimuli during the interictal phase.Methods.-LEPs were recorded to stimulation of both the right hand and the right perioral region in 14 patients and in 14 healthy subjects. The habituation of both the N1 and the vertex N2/P2 components was assessed by measuring the LEP amplitude changes across 3 consecutive repetitions of 30 trials each.Results.-In the 8 patients who had clinically improved after treatment, the N2/P2 amplitude habituation was significantly higher after treatment than before treatment following both hand (F = 43.2, P < .0001) and face stimulation (F = 6.9, P = .01). In these patients, the N2/P2 amplitude habituation after treatment was not different from that obtained in healthy controls (P = .18 and P = .73 for hand and face stimulation, respectively). On the contrary, in the patients who did not improve, the N2/P2 amplitude still showed reduced habituation after both hand (F = 3.1, P = .08) and face (F = 0.7, P = .4) stimulation.Conclusion.-The deficient habituation of the vertex N2/P2 complex was partly restored after successful treatment of medication-overuse headache, reflecting a modification in pain-processing pathways