Using event-related brain potentials to evaluate motor-auditory latencies in virtual reality

Actions in the real world have immediate sensory consequences. Mimicking these in digital environments is within reach, but technical constraints usually impose a certain latency (delay) between user actions and system responses. It is important to assess the impact of this latency on the users, ideally with measurement techniques that do not interfere with their digital experience. One such unobtrusive technique is electroencephalography (EEG), which can capture the users' brain activity associated with motor responses and sensory events by extracting event-related potentials (ERPs) from the continuous EEG recording. Here we exploit the fact that the amplitude of sensory ERP components (specifically, N1 and P2) reflects the degree to which the sensory event was perceived as an expected consequence of an own action (self-generation effect). Participants (N = 24) elicit auditory events in a virtual-reality (VR) setting by entering codes on virtual keypads to open doors. In a within-participant design, the delay between user input and sound presentation is manipulated across blocks. Occasionally, the virtual keypad is operated by a simulated robot instead, yielding a control condition with externally generated sounds. Results show that N1 (but not P2) amplitude is reduced for self-generated relative to externally generated sounds, and P2 (but not N1) amplitude is modulated by delay of sound presentation in a graded manner. This dissociation between N1 and P2 effects maps back to basic research on self-generation of sounds. We suggest P2 amplitude as a candidate read-out to assess the quality and immersiveness of digital environments with respect to system latency

Das ILZNAWI-Modell: Inklusive Lernzugänge im naturwissenschaftlichen Unterricht. Zur Planbarkeit von Individualisierung und Kooperation am Gemeinsamen Gegenstand

Der Beitrag stellt das im Rahmen des Projekts „Reckahner Modelle zur inklusiven Unterrichtsplanung“ (REMI) entwickelte ILZNAWI-Modell („Inklusive Lernzugänge im naturwissenschaftlichen Unterricht“) vor. Es dient dazu, den Gemeinsamen Gegenstand im naturwissenschaftlichen Unterricht inklusionsförderlich und heterogenitätssensibel auszudifferenzieren und bildet auf Grundlage eines weiten Inklusionsverständnisses gestufte Lernzugänge und Abstraktionsgrade ab. Der Artikel gibt einen Überblick über diesbezüglich bestehende Forschungsprojekte und Unterrichtskonzepte, leitet hieraus die Notwendigkeit für das Modell ab und anschließend dessen Entwicklung theoretisch her. Anhand ausgewählter Stufenmodelle für die Fächer Biologie, Physik und Chemie wird die Planungsanwendung konkretisiert. In einer Unterrichtssequenz zur Evolution des Menschen werden Möglichkeiten zur Verbindung von Individualisierung und Kooperation aufgezeigt. Weitere Umsetzungsideen der Fächer Chemie und Physik verdeutlichen die Bandbreite an Nutzungsmöglichkeiten des Modells. (DIPF/Orig.

Post-mortem computed tomography is a useful tool for determining the pulmonary ventilation status in newborns

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Introduction</jats:title> <jats:p>Lung ventilation is a standard sign of life in newborns. Post-mortem computed tomography (PMCT) is highly sensitive to the presence of gas in the body including the lungs. Current standard examinations to determine the pulmonary ventilation status in newborns are the flotation test and histology. The purpose of this study was to compare the accuracy of PMCT with the flotation test for determining the lung ventilation status with histological control as reference standard. A cut-off value as CT number in Hounsfield Units (HU) determining lung ventilation of newborns in PMCT should be established.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>A total of 38 infant lungs were examined of which 21 lungs were from infants deceased shortly after live birth (control group) and 17 lungs belonged to infants where live birth was in question (study group). All lungs were examined using PMCT, flotation test, and histological examination.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>The control group showed an overall mean attenuation ± standard deviation of −219 HU ± 135; the study group of 45 ± 15 HU in histologically nonventilated lungs versus −192 ± 207 HU; (<jats:italic>p</jats:italic> < 0.001) in ventilated lungs. The best cut-off value for optimal discrimination of ventilated and nonventilated lungs in newborns was −35 mean HU.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusion</jats:title> <jats:p>PMCT is equally well suited to determine lung ventilation as the flotation test. It provides additional information regarding pulmonary infiltration, degree of putrefaction, or signs of trauma (fractures, pneumothorax). Histology remains mandatory in ambiguous cases.</jats:p> </jats:sec&gt

Severe Human Bocavirus 1 Respiratory Tract Infection in an Immunodeficient Child With Fatal Outcome

We report a case of lower respiratory tract infection with human bocavirus 1 (HboV1) in an immunodeficient 6-month-old boy leading to respiratory failure with fatal outcome. Polymerase chain reaction of serum/tracheal secretions revealed exceptionally high HboV1-DNA levels and immunoassays showed seroconversion indicating an acute primary HboV1 infection. All assays for other pathogens were negative, strongly suggesting that HboV1 was the causative agent in this case.Peer reviewe

Comparison of symptomatic and asymptomatic atherosclerotic carotid plaques using parallel imaging and 3 T black-blood in vivo CMR

Background: To determine if black-blood 3 T cardiovascular magnetic resonance (bb-CMR) can depict differences between symptomatic and asymptomatic carotid atherosclerotic plaques in acute ischemic stroke patients. Methods: In this prospective monocentric observational study 34 patients (24 males; 70 +/- 9.3 years) with symptomatic carotid disease defined as ischemic brain lesions in one internal carotid artery territory on diffusion weighted images underwent a carotid bb-CMR at 3 T with fat-saturated pre- and post-contrast T1w-, PDw-, T2w- and TOF images using surface coils and Parallel Imaging techniques (PAT factor = 2) within 10 days after symptom onset. All patients underwent extensive clinical workup (lab, brain MR, duplex sonography, 24-hour ECG, transesophageal echocardiography) to exclude other causes of ischemic stroke. Prevalence of American Heart Association lesion type VI (AHA-LT6), status of the fibrous cap, presence of hemorrhage/thrombus and area measurements of calcification, necrotic core and hemorrhage were determined in both carotid arteries in consensus by two reviewers who were blinded to clinical information. McNemar and Wilcoxon's signed rank tests were use for statistical comparison. A p-value <0.05 was considered statistically significant. Results: Symptomatic plaques showed a higher prevalence of AHA-LT6 (67.7% vs. 11.8%; p < 0.001; odds ratio = 12.5), ruptured fibrous caps (44.1% vs. 2.9%; p < 0.001; odds ratio = 15.0), juxtaluminal thrombus (26.5 vs. 0%; < 0.01; odds ratio = 7.3) and intraplaque hemorrhage (58.6% vs. 11.8%; p = 0.01; odds ratio = 3.8). Necrotic core and hemorrhage areas were greater in symptomatic plaques (14.1 mm(2) vs. 5.5 mm(2) and 13.6 mm(2) vs. 5.3 mm(2); p < 0.01, respectively). Conclusion: 3 T bb-CMR is able to differentiate between symptomatic and asymptomatic carotid plaques, demonstrating the potential of bb-CMR to differentiate between stable and vulnerable lesions and ultimately to identify patients with low versus high risk for cardiovascular complications. Best predictors of the symptomatic side were a ruptured fibrous cap, AHA-LT 6, juxtaluminal hemorrhage/thrombus, and intraplaque hemorrhage

Differentiation of heroin and cocaine using dual-energy CT—an experimental study

Objective: To evaluate if heroin and cocaine can be distinguished using dual-energy CT. Materials and methods: Twenty samples of heroin and cocaine at different concentrations and standardized compression (SC) were scanned in dual-energy mode on a newest generation Dual Energy 64-row MDCT scanner. CT number, spectral graphs, and dual-energy index (DEI) were evaluated. Results were prospectively tested on six original samples from a body packer. Wilcoxon's test was used for statistical evaluation. Results: Values are given as median and range. Under SC, the CT number of cocaine samples (−29.87 Hounsfield unit (HU) [−125.85; 16.16HU]) was higher than the CT number of heroin samples (−184.37HU [−199.81; −159.25HU]; p < 0.01). Slope of spectral curves for cocaine was −2.36HU/keV [−7.15; −0.67HU/keV], and for heroin, 1.75HU/keV [1.28; 2.5HU/keV] (p < 0.01). DEI was 0.0352 [0.0081; 0.0528] for cocaine and significantly higher than for heroin samples (−0.0127 [−0.0097; −0.0159]; p < 0.001). While CT number was inconclusive, all six original packs were correctly classified after evaluation of the spectral curve and DEI. In contrast to the CT number, slope of the spectral curve and DEI were independent of concentration and compression. Conclusion: The slope of the spectral curve and the DEI from dual-energy CT data can be used to distinguish heroin and cocaine in vitro; these results are independent of compression and concentration in the measured range

Erratum: Location of crossings in the Floquet spectrum of a driven two-level system (vol B 67, art no 165301, 2003)

Background: The purpose of this prospective study was to perform a head-to-head comparison of the two methods most frequently used for evaluation of carotid plaque characteristics: Multi-detector Computed Tomography Angiography (MDCTA) and black-blood 3 T-cardiovascular magnetic resonance (bb-CMR) with respect to their ability to identify symptomatic carotid plaques. Methods: 22 stroke unit patients with unilateral symptomatic carotid disease and > 50% stenosis by duplex ultrasound underwent MDCTA and bb-CMR (TOF, pre- and post-contrast fsT1w-, and fsT2w-sequences) within 15 days of symptom onset. Both symptomatic and contralateral asymptomatic sides were evaluated. By bb-CMR, plaque morphology, composition and prevalence of complicated AHA type VI lesions (AHA-LT6) were evaluated. By MDCTA, plaque type (non-calcified, mixed, calcified), plaque density in HU and presence of ulceration and/or thrombus were evaluated. Sensitivity (SE), specificity (SP), positive and negative predictive value (PPV, NPV) were calculated using a 2-by-2-table. Results: To distinguish between symptomatic and asymptomatic plaques AHA-LT6 was the best CMR variable and presence/absence of plaque ulceration was the best CT variable, resulting in a SE, SP, PPV and NPV of 80%, 80%, 80% and 80% for AHA-LT6 as assessed by bb-CMR and 40%, 95%, 89% and 61% for plaque ulceration as assessed by MDCTA. The combined SE, SP, PPV and NPV of bb-CMR and MDCTA was 85%, 75%, 77% and 83%, respectively. Conclusions: Bb-CMR is superior to MDCTA at identifying symptomatic carotid plaques, while MDCTA offers high specificity at the cost of low sensitivity. Results were only slightly improved over bb-CMR alone when combining both techniques

Sumoylation inhibits α-synuclein aggregation and toxicity

Sumoylation of α-synuclein decreases its rate of aggregation and its deleterious effects in vitro and in vivo