107 research outputs found
Probing Time-Dependent Molecular Dipoles on the Attosecond Time Scale
Photoinduced molecular processes start with the interaction of the
instantaneous electric field of the incident light with the electronic degrees
of freedom. This early attosecond electronic motion impacts the fate of the
photoinduced reactions. We report the first observation of attosecond time
scale electron dynamics in a series of small- and medium-sized neutral
molecules (N2, CO2, and C2H4), monitoring time-dependent variations of the
parent molecular ion yield in the ionization by an attosecond pulse, and
thereby probing the time-dependent dipole induced by a moderately strong near-
infrared laser field. This approach can be generalized to other molecular
species and may be regarded as a first example of molecular attosecond Stark
spectroscopy
Temporal delay discounting in acutely ill and weight-recovered patients with anorexia nervosa
Background. Patients with anorexia nervosa (AN) are characterized by a very low body weight but readily give up immediate rewards (food) for long-term goals (slim figure), which might indicate an unusual level of self-control. This everyday clinical observation may be quantifiable in the framework of the anticipation-discounting dilemma. Method. Using a cross-sectional design, this study compared the capacity to delay reward in 34 patients suffering from acute AN (acAN), 33 weight-recovered AN patients (recAN) and 54 healthy controls. We also used a longitudinal study to reassess 21 acAN patients after short-term weight restoration. A validated intertemporal choice task and a hyperbolic model were used to estimate temporal discounting rates. Results. Confirming the validity of the task used, decreased delay discounting was associated with age and low selfreported impulsivity. However, no group differences in key measures of temporal discounting of monetary rewards were found. Conclusions. Increased cognitive control, which has been suggested as a key characteristic of AN, does not seem to extend the capacity to wait for delayed monetary rewards. Differences between our study and the only previous study reporting decreased delay discounting in adult AN patients may be explained by the different age range and chronicity of acute patients, but the fact that weight recovery was not associated with changes in discount rates suggests that discounting behavior is not a trait marker in AN. Future studies using paradigms with disorder-specific stimuli may help to clarify the role of delay discounting in AN
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The effect of trepanning speed of laser drilled acute angled cooling holes on the high temperature low cycle corrosion fatigue performance of CMSX-4 at 850 °C
The effect of laser trepanning speed and, as a result, recast layer thickness on the high temperature corrosion fatigue behaviour of CMSX-4 superalloy acute angled holes was investigated. The experimental test results show that an increasing laser drilling speed caused a reduction in corrosion fatigue life by 35–50% at 850 °C, under low cycle fatigue regime. This reduction was found to correlate directly with the recast layer thickness and surface anomalies within the recast layer produced during the laser drilling process. Corrosion had a smaller effect on the overall life of the laser drilled specimens under the conditions tested. The results presented show that laser trepanning speed is influential in limiting the life performance of laser drilled components in service
Effects of the magnetic moment interaction between nucleons on observables in the 3N continuum
The influence of the magnetic moment interaction of nucleons on
nucleon-deuteron elastic scattering and breakup cross sections and on elastic
scattering polarization observables has been studied. Among the numerous
elastic scattering observables only the vector analyzing powers were found to
show a significant effect, and of opposite sign for the proton-deuteron and
neutron-deuteron systems. This finding results in an even larger discrepancy
than the one previously established between neutron-deuteron data and
theoretical calculations. For the breakup reaction the largest effect was found
for the final-state-interaction cross sections. The consequences of this
observation on previous determinations of the ^1S_0 scattering lengths from
breakup data are discussed.Comment: 24 pages, 6 ps figures, 1 png figur
Validierung innerklinischer Sichtungsalgorithmen für den Massenanfall von Verletzten – eine simulationsbasierte Studie – deutsche Version
Hintergrund
Die situationsbedingte Verknappung medizinischer Ressourcen endet bei einem Massenanfall von Verletzen (MANV) lageabhängig nicht mit dem Abtransport der Patienten von der Einsatzstelle. Folglich ist in den aufnehmenden Kliniken eine Eingangssichtung erforderlich. Ziel dieser Studie war es im ersten Schritt einen Referenz‐Patientenvignettensatz mit definierten Sichtungskategorien zu erstellen. Dies erlaubte im zweiten Schritt, die rechnergestützte Evaluation der diagnostischen Güte klinischer Sichtungsalgorithmen für MANV-Lagen.
Methodik
In einen mehrstufigen Bewertungsprozess durch zunächst sechs, später 36 Sichtungsexperten gingen 250 in der Übungspraxis validierte Fallvignetten ein. Diese Algorithmen – unabhängige Expertenbewertung aller Vignetten – dienten als Goldstandard für die Analyse der diagnostischen Güte der folgenden innerklinischen Algorithmen: Manchester Triage System (MTS Modul MANV), Emergency severity Index (ESI), Berliner Sichtungsalgorithmus (BER), die prähospitalen Algorithmen PRIOR und mSTaRT, sowie zwei Projektalgorithmen aus einer Kooperation des Bundesamts für Bevölkerungsschutz und Katastrophenhilfe (BBK) mit dem Haschemitischen Königreich Jordanien – innerklinischer jordanisch-deutscher Projektalgorithmus (JorD) und prähospitaler Sichtungsalgorithmus (PETRA). Jede Patientenvignette durchlief computergestützt eine Sichtung durch alle angegeben Algorithmen, um vergleichend die Testgüte für alle Verfahren zu erheben.
Ergebnisse
Von den ursprünglich 250 Vignetten konnte eine Sichtungsreferenzdatenbank mit 210 Patientenvignetten algorithmenunabhängig validiert werden. Diese bildeten den Goldstandard für den Vergleich der analysierten Sichtungsalgorithmen. Die Sensitivitäten für die innerklinische Detektion von Patienten der Sichtungskategorie I lagen zwischen 1,0 (BER, JorD, PRIOR) und 0,57 (MANV-Modul MTS). Die Spezifitäten lagen zwischen 0,99 (MTS und PETRA) und 0,67 (PRIOR). Gemessen am Youden-Index ergab sich bei BER (0,89) und JorD (0,88) die beste Gesamtperformance für die Detektion von Patienten der Sichtungskategorie I. Eine Übertriage ist am ehesten bei PRIOR, eine Untertriage beim MANV-Modul von MTS zu erwarten. Bis zum Entscheid SK I benötigen die Algorithmen folgende Schrittanzahlen (Median [IQR]): ESI 1 [1–2]; JorD 1 [1–4]; PRIOR 3 [2–4]; BER 3 [2–6]; mSTaRT 3 [3–5]; MTS 4 [4–5]; PETRA 6 [6–8]. Für die SK II und III besteht ein positiver Zusammenhang zwischen der Schrittanzahl bis zum Entscheid und der Testgüte.
Schlussfolgerung
In der vorliegenden Studie konnte eine Übertragbarkeit prähospitaler algorithmenbasierter Vorsichtungsergebnisse auf die Ergebnisse klinischer Algorithmen gezeigt werden. Die höchste diagnostische Güte für die innerklinischen Sichtung lieferten BER und JorD, die allerdings auch die meisten Algorithmusschritte bis zum Entscheid benötigen
RA-specific expression profiles and new candidate genes
Objective:
To identify rheumatoid arthritis- (RA)-specific profiles of differentially expressed genes.
Methods:
Synovial tissues from RA and osteoarthritis (OA) patients and from normal joints were selected according to their disease-characteristic histology. Gene expression was analyzed using DNA microarrays (GeneChip; Unigene-array) and representational difference analysis (RDA). Data were validated on larger cohorts of patients by RT-PCR.
Results:
Nine hundred and eighty genes were significantly regulated in RA synovial tissue as compared with non-RA. Specialized cluster analysis identified a set of 312 genes as sufficient of unequivocally discriminating RA from non-RA patterns (class discovery). Genes of highest regulation were associated with leukocyte activation (chemokines, chemokine receptors, B- and T-cell genes), endothelial and angiogenic
activation, tissue destruction and remodelling [MMP-3, BMP-4, TIMPs]. Interestingly, a large set of genes was down-regulated in RA (TGF-β superfamily, apoptosis-related genes, transcription factors). Osteopontin-like genes (n=46) — up-regulated in RA — and glutathione peroxidase-3-like genes (n=85) — down-regulated in RA — yielded the highest correlation coefficients (>0.94). Megakaryocyte stimulating factor (MSF), down-regulated in a subset of RA, may hold the key to subclassification: a loss-of-function mutation in the MSF-encoding gene leads to synovial hyperplasia in camptodactyly–arthropathy–coxa vara–pericarditis syndrome, and, as in RA, also to pericardial involvement. A further candidate, vitamin-D3-up-regulated protein-1 (VDUP-1), is regulated like MSF and predisposes to premature coronary artery disease when mutated, again a feature of a subset of RA.
Conclusion:
RA specific gene profiles were identified and are useful to improve diagnostics of the disease. Novel gene candidates not yet in the focus of RA pathogenesis have been identified that are likely to further the understanding of RA
Covid-19 triage in the emergency department 2.0: how analytics and AI transform a human-made algorithm for the prediction of clinical pathways
The Covid-19 pandemic has pushed many hospitals to their capacity limits. Therefore, a triage of patients has been discussed controversially primarily through an ethical perspective. The term triage contains many aspects such as urgency of treatment, severity of the disease and pre-existing conditions, access to critical care, or the classification of patients regarding subsequent clinical pathways starting from the emergency department. The determination of the pathways is important not only for patient care, but also for capacity planning in hospitals. We examine the performance of a human-made triage algorithm for clinical pathways which is considered a guideline for emergency departments in Germany based on a large multicenter dataset with over 4,000 European Covid-19 patients from the LEOSS registry. We find an accuracy of 28 percent and approximately 15 percent sensitivity for the ward class. The results serve as a benchmark for our extensions including an additional category of palliative care as a new label, analytics, AI, XAI, and interactive techniques. We find significant potential of analytics and AI in Covid-19 triage regarding accuracy, sensitivity, and other performance metrics whilst our interactive human-AI algorithm shows superior performance with approximately 73 percent accuracy and up to 76 percent sensitivity. The results are independent of the data preparation process regarding the imputation of missing values or grouping of comorbidities. In addition, we find that the consideration of an additional label palliative care does not improve the results
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