Performance assessment of time-domain optical brain imagers, part 1: basic instrumental performance protocol

open21siAbstract.  Performance assessment of instruments devised for clinical applications is of key importance for validation and quality assurance. Two new protocols were developed and applied to facilitate the design and optimization of instruments for time-domain optical brain imaging within the European project nEUROPt. Here, we present the “Basic Instrumental Performance” protocol for direct measurement of relevant characteristics. Two tests are discussed in detail. First, the responsivity of the detection system is a measure of the overall efficiency to detect light emerging from tissue. For the related test, dedicated solid slab phantoms were developed and quantitatively spectrally characterized to provide sources of known radiance with nearly Lambertian angular characteristics. The responsivity of four time-domain optical brain imagers was found to be of the order of 0.1  m2 sr. The relevance of the responsivity measure is demonstrated by simulations of diffuse reflectance as a function of source-detector separation and optical properties. Second, the temporal instrument response function (IRF) is a critically important factor in determining the performance of time-domain systems. Measurements of the IRF for various instruments were combined with simulations to illustrate the impact of the width and shape of the IRF on contrast for a deep absorption change mimicking brain activation.H. Wabnitz; D. R. Taubert; M. Mazurenka; O. Steinkellner; A. Jelzow;R. Macdonald;D. Milej;P. Sawosz;M. Kacprzak;A. Liebert;R. Cooper;J. Hebden;A. Pifferi;A. Farina;I. Bargigia;D. Contini;M. Caffini;L. Zucchelli;L. Spinelli;R. Cubeddu;A. TorricelliH., Wabnitz; D. R., Taubert; M., Mazurenka; O., Steinkellner; A., Jelzow; R., Macdonald; D., Milej; P., Sawosz; M., Kacprzak; A., Liebert; R., Cooper; J., Hebden; Pifferi, ANTONIO GIOVANNI; Farina, Andrea; Bargigia, Ilaria; Contini, Davide; Caffini, Matteo; Zucchelli, LUCIA MARIA GRAZIA; Spinelli, Lorenzo; Cubeddu, Rinaldo; Torricelli, Alessandr

Performance assessment of time-domain optical brain imagers, part 2: nEUROPt protocol

The nEUROPt protocol is one of two new protocols developed within the European project nEUROPt to characterize the performances of time-domain systems for optical imaging of the brain. It was applied in joint measurement campaigns to compare the various instruments and to assess the impact of technical improvements. This protocol addresses the characteristic of optical brain imaging to detect, localize, and quantify absorption changes in the brain. It was implemented with two types of inhomogeneous liquid phantoms based on Intralipid and India ink with well-defined optical properties. First, small black inclusions were used to mimic localized changes of the absorption coefficient. The position of the inclusions was varied in depth and lateral direction to investigate contrast and spatial resolution. Second, two-layered liquid phantoms with variable absorption coefficients were employed to study the quantification of layer-wide changes and, in particular, to determine depth selectivity, i.e., the ratio of sensitivities for deep and superficial absorption changes. We introduce the tests of the nEUROPt protocol and present examples of results obtained with different instruments and methods of data analysis. This protocol could be a useful step toward performance tests for future standards in diffuse optical imaging

Ultrafast vibrational excitation and time resolved experiments on the dissociation of water in the gas phase

Titel, Abstract und Kurzfassung Inhalts-, Abbildungs- und Tabellenverzeichnis 1\. Einleitung 1 2\. Stand der Forschung 5 2.1 Einige Vorbemerkungen zur Dissoziation von Wasser 5 2.2 Vibrationsanregung und selektive Dissoziation von HDO 15 3\. Erzeugung und Vermessung ultrakurzer Lichtimpulse 23 3.1 Erzeugung ultrakurzer Lichtimpulse 23 3.2 Methoden der Frequenzkonversion 26 3.3 Vermessung der Laserparameter 30 3.4 Spezielle Erzeugungs- und Konversionstechniken 33 3.5 Beschreibung der Lasersysteme 47 4\. Nachweis und Analyse photoinduzierter Reaktionen 57 4.1 Nachweismethoden 57 4.2 Datenauswertung 62 5\. Messergebnisse und Interpretation 69 5.1 Zweifarben-Ionisationsexperimente 69 5.2 Dissoziation über den B-Zustand 83 5.3 Dissoziation über den C- und D-Zustand 110 6\. Zusammenfassung und Ausblick 123 Anhang 126 Literaturverzeichnis 131 DanksagungDiese Arbeit beschäftigt sich zum einen mit der zeitaufgelösten Untersuchung der Dissoziation von Wasser und seinen deuterierten Isotopomeren, zum anderen mit der Anregung von Vibrationszuständen im elektronischen Grundzustand durch ultrakurze Laserimpulse. Dazu werden ultrakurze Laserpulse im Vakuum-Ultravioletten bei 155 nm erzeugt und charakterisiert. Desweiteren finden Laserimpulse Anwendung, die auf bis zu 8 fs bei 400 nm und 15 fs bei 800 nm verkürzt sind, sowie intensive Laserimpulse im mittleren Infrarot bis 3.9 µm. Zum Nachweis dienen Pump- Abtast-Messungen in Verbindung mit Flugzeit-Massenspektrometrie und der Messung der spontanen Fluoreszenz von OH(A). Zur Dynamik der direkten Dissoziation von H2O, HDO und D2O über den A-Zustand wird eine zeitaufgelöste Ionisationsmessung mit Einphotonenanregung dargestellt, durch welche die Lebensdauer dieses Zustands auf unter 20 fs eingegrenzt werden kann. Der nächste Abschnitt zeigt die Möglichkeit der Voranregung der fundamentalen Biegeschwingung in HDO durch impulsive Ramanstreuung mit Hilfe eines Ionisationsexperiments. Die kohärente Kontrolle der Dissoziation durch Voranregung von Kombinationsschwingungen wird mit ultrakurzen Laserimpulsen bei 2.4 µm und 3.6 µm getestet, wobei die Dissoziation über den B-Zustand erfolgt. Dieser Zustand verdeutlicht den Einfluss nichtadiabatischer Kopplungsprozesse: Abhängig von der Dissoziationswellenlänge kann mit Hilfe eines zusätzlichen Photons im infraroten Spektralbereich die direkte Dissoziation bevorzugt angesteuert oder der Transit durch eine konische Durchschneidung stimuliert werden. Der letzte Abschnitt untersucht die Dissoziation über C- und D-Zustand. Während dem C-Zustand eine durch Rotation vermittelte heterogene Prädissoziation zugeordnet werden kann, zeigt der D-Zustand eine durch die starke Kopplung zum B-Zustand bedingte homogene Prädissoziation.This work presents time resolved investigations on the dissociation of water and its deuterated isotopomers and the excitation of vibrational states on the electronic ground state by ultrashort laser pulses. Ultrashort pulses in the vacuum ultraviolet at 155 nm are generated and characterized. In addition laser pulses shortened up to 8 fs at 400 nm and 15 fs at 800 nm are used, as well as intensive radiation in the mid infrared up to 3.9 µm. As experimental techniques pump-probe measurements connected with time-of-flight mass-spectrometry or the sampling of the spontaneous fluorescence of OH(A) are applied. First time-resolved ionization measurements on the dynamics of the dissociation of H2O, HDO and D2O via the A-state of these molecules are shown. Employing one-photon excitation an upper limit for the lifetime of this state of 20 fs can be estimated. In the next part the preexcitation of the fundamental bending vibration in HDO by impulsive Raman scattering is demonstrated in an ionization experiment. Further coherent control of the dissociation is tested by excitation of superpositions of vibrational modes with ultrashort laser pulses at 2.4 µm and 3.6 µm and subsequent dissociation on the B-state. This state shows influence of non-adiabatic coupling: Dependent on the dissociation wavelength and induced by an additional photon in the infrared spectral range the direct dissociation can be favored or the transit through a conical intersection can be stimulated. The last part examines the dissociation via C-state and D-state. A heterogeneous predissociation mediated by rotation can be assigned to the C-state, whereas the D-state shows a homogeneous predissociation caused by the strong coupling to the B-state

Identification and molecular characterisation of a homozygous missense mutation in the ADAMTS10 gene in a patient with Weill-Marchesani syndrome

Weill-Marchesani syndrome is a rare disorder of the connective tissue. Functional variants in ADAMTS10 are associated with Weill-Marchesani syndrome-1. We identified a homozygous missense mutation, c.41T>A, of the ADAMTS10 gene in a 19-year-old female with typical symptoms of WMS1: proportionate short stature, brachydactyly, joint stiffness, and microspherophakia. The ADAMTS10 missense mutation was analysed in silico, with conflicting results as to its effects on protein function, but it was predicted to affect the leader sequence. Molecular characterisation in HEK293 Ebna cells revealed an intracellular mis-targeting of the ADAMTS10 protein with a reduced concentration of the polypeptide in the endoplasmic reticulum. A large reduction in glycosylation of the cytoplasmic fraction of the mutant ADAMTS10 protein versus the wild-type protein and a lack of secretion of the mutant protein are also evident in our results.In conclusion, we identified a novel missense mutation of the ADAMTS10 gene and confirmed the functional consequences suggested by the in silico analysis by conducting molecular studies

GLM analysis of time resolved NIRS data of motor activation during different motor tasks

The hemodynamic response to motor activation was investigated by time-resolved NIRS in healthy subjects and patients with unilateral impairment in motor ability. Healthy subjects performed a simple and a complex finger movement task, patients a handgrip task. A General Linear Model approach (GLM) was applied during NIRS data processing. In general, compared to the integral (continuous wave signal), higher significance of activation was found for the variance signal that selectively represents changes in the deep compartment. A discussion of GLM results with respect to task complexity and difficulty is provided

Amphetamine action at the cocaine- and antidepressant-sensitive serotonin transporter is modulated by αCaMKII.

Serotonergic neurotransmission is terminated by reuptake of extracellular serotonin (5-HT) by the high-affinity serotonin transporter (SERT). Selective 5-HT reuptake inhibitors (SSRIs) such as fluoxetine or escitalopram inhibit SERT and are currently the principal treatment for depression and anxiety disorders. In addition, SERT is a major molecular target for psychostimulants such as cocaine and amphetamines. Amphetamine-induced transport reversal at the closely related dopamine transporter (DAT) has been shown previously to be contingent upon modulation by calmodulin kinase IIα (αCaMKII). Here, we show that not only DAT, but also SERT, is regulated by αCaMKII. Inhibition of αCaMKII activity markedly decreased amphetamine-triggered SERT-mediated substrate efflux in both cells coexpressing SERT and αCaMKII and brain tissue preparations. The interaction between SERT and αCaMKII was verified using biochemical assays and FRET analysis and colocalization of the two molecules was confirmed in primary serotonergic neurons in culture. Moreover, we found that genetic deletion of αCaMKII impaired the locomotor response of mice to 3,4-methylenedioxymethamphetamine (also known as "ecstasy") and blunted d-fenfluramine-induced prolactin release, substantiating the importance of αCaMKII modulation for amphetamine action at SERT in vivo as well. SERT-mediated substrate uptake was neither affected by inhibition of nor genetic deficiency in αCaMKII. This finding supports the concept that uptake and efflux at monoamine transporters are asymmetric processes that can be targeted separately. Ultimately, this may provide a molecular mechanism for putative drug developments to treat amphetamine addiction