[Potential Impact of Public Communication on Emergency Presentations due to Headache during the Covid-19 Pandemic]. / Epidemiologische Untersuchung zu möglichen Auswirkungen öffentlicher Kommunikation im Rahmen der COVID-19-Pandemie auf Notfallvorstellungen von Kopfschmerzpatient*innen.

Headache is a frequent presenting symptom in the emergency department. While most cases are of benign aetiology, it is crucially important to identify potentially dangerous underlying disorders. We hypothesized an increase in headache-related emergency presentations after venous thrombosis of cerebral sinuses had been identified as a rare side effect of vaccination with adenovirus vector-based Coronavirus-disease 2019 (COVID-19) vaccines and that information had been publicly communicated by the Paul Ehrlich Institute. Data from patients with the diagnosis of primary headache disorders or unspecified headache presenting to the Interdisciplinary Emergency Department of the University Medicine Mannheim were retrospectively analysed. Based on vaccination dashboard data published by the Federal Ministry of Health, calendar weeks 14-30 and 47-48, on the one hand, and 1-13 and 31-46, on the othe, were categorized into a variable "vaccination epoch" (14-30, 47-48: high vaccination activity if≥3 million weekly vaccinations in Germany; 1-13, 31-46: low vaccination activity if<3 million weekly vaccinations). The number of patients with headache was the dependent variable. A Poisson regression was performed to analyze whether the frequency of events, i. e., patient presentations, was a function of year (2019, 2021), epoch (high, low) and an interaction of year and epoch - the latter reflecting an impact of vaccination activity during the pandemic and expressed as incidence rate ratio. Compared to 2019, there was a more than 70% increase in presentations due to headache during periods of high vaccination activity in 2021 (p<0.001; 95% confidence interval 1.272-2.316), in 25% of presentations in 2021, patients considered their headache as vaccination-associated. Public communication and resulting nocebo effects may, among other factors, have contributed to our observation of increased numbers of emergency headache presentations, illustrating the impact of public distribution of medical information on practical aspects of emergency care during crises.

Central retinal artery occlusion as a neuro-ophthalmological emergency: the need to raise public awareness.

BACKGROUND AND PURPOSE: Central retinal artery occlusion (CRAO) is a neuro-ophthalmological emergency necessitating adequate and comprehensive diagnosis. Its optimal management and treatment, however, are still under debate. This study aimed at identifying respective areas for improvement. METHODS: We retrospectively analysed the medical records of patients with CRAO treated in our stroke unit between January 2016 and August 2020. RESULTS: During the observational period, 101 patients with CRAO were admitted. We observed an increase in the rate of patients primarily admitted to the stroke unit from 52.2% to 97.4%. In addition, the thrombolysis rate - with thrombolysis performed on an individual basis - rose from 0% to 14.1%, coinciding with the implementation of an in-hospital management guideline. Almost 60% of all patients presented outside of the 4.5-h time window for thrombolysis; by far the most common reason not to deliver intravenous thrombolysis in our cohort was a prehospital delay to presentation (58.8%), with 44.4% of patients having consulted a private-practice ophthalmologist first. A total of 25 (32.5%) of 77 patients who underwent magnetic resonance imaging (MRI) had accompanying acute ischaemic stroke lesions on diffusion-weighted MRI of the brain. A possible aetiology of CRAO was identified in 41.4% of patients. DISCUSSION: Public awareness of sudden unilateral visual loss as a presenting sign for stroke should be raised, increasing the chances for timely recognition in a hospital with ophthalmological expertise and a stroke centre. This is essential for ongoing and future prospective trials on this subject.

Decreased utilization of mental health emergency service during the COVID-19 pandemic.

During the rapid rise of the COVID-19 pandemic, a reduction of the numbers of patients presenting to emergency departments has been observed. We present an early study from a German psychiatric hospital to assess the dynamics of mental health emergency service utilization rates during the COVID-19 pandemic. Our results show that the numbers of emergency presentations decreased, and a positive correlation between these numbers and mobility of the general public suggests an impact of extended measures of social distancing. This finding underscores the necessity of raising and sustaining awareness regarding the threat to mental health in the context of the pandemic.

Acute Stroke in Times of the COVID-19 Pandemic: A Multicenter Study.

BACKGROUND AND PURPOSE: This study aims to assess the number of patients with acute ischemic cerebrovascular events seeking in-patient medical emergency care since the implementation of social distancing measures in the coronavirus disease 2019 (COVID-19) pandemic. METHODS: In this retrospective multicenter study, data on the number of hospital admissions due to acute ischemic stroke or transient ischemic attack and numbers of reperfusion therapies performed in weeks 1 to 15 of 2020 and 2019 were collected in 4 German academic stroke centers. Poisson regression was used to test for a change in admission rates before and after the implementation of extensive social distancing measures in week 12 of 2020. The analysis of anonymized regional mobility data allowed for correlations between changes in public mobility as measured by the number and length of trips taken and hospital admission for stroke/transient ischemic attack. RESULTS: Only little variation of admission rates was observed before and after week 11 in 2019 and between the weeks 1 and 11 of 2019 and 2020. However, reflecting the impact of the COVID-19 pandemic, a significant decrease in the number of admissions for transient ischemic attack was observed (-85%, -46%, -42%) in 3 of 4 centers, while in 2 of 4 centers, stroke admission rates decreased significantly by 40% and 46% after week 12 in 2020. A relevant effect on reperfusion therapies was found for 1 center only (thrombolysis, -60%; thrombectomy, -61%). Positive correlations between number of ischemic events and mobility measures in the corresponding cities were identified for 3 of 4 centers. CONCLUSIONS: These data demonstrate and quantify decreasing hospital admissions due to ischemic cerebrovascular events and suggest that this may be a consequence of social distancing measures, in particular because hospital resources for acute stroke care were not limited during this period. Hence, raising public awareness is necessary to avoid serious healthcare and economic consequences of undiagnosed and untreated strokes and transient ischemic attacks.

The novel seizure quality index for the antidepressant outcome prediction in electroconvulsive therapy: association with biomarkers in the cerebrospinal fluid.

For patients with depression treated with electroconvulsive therapy (ECT), the novel seizure quality index (SQI) can predict the risk of non-response (and non-remission)-as early as after the second ECT session-based the extent of several ictal parameters of the seizure. We aim to test several CSF markers on their ability to predict the degree of seizure quality, measured by the SQI to identify possible factors, that could explain some variability of the seizure quality. Baseline CSF levels of metabolites from the kynurenine pathway, markers of neurodegeneration (tau proteins, ß-amyloids and neurogranin), elements of the innate immune system, endocannabinoids, sphingolipids, neurotrophic factors (VEGF) and Klotho were measured before ECT in patients with depression (n = 12) to identify possible correlations with the SQI by Pearson's partial correlation. Negative, linear relationships with the SQI for response were observed for CSF levels of T-tau (rpartial = - 0.69, p = 0.019), phosphatidylcholines (rpartial = - 0.52, p = 0.038) and IL-8 (rpartial = - 0.67, p = 0.047). Regarding the SQI for remission, a negative, linear relationship was noted with CSF levels of the endocannabinoid AEA (rpartial = - 0.70, p = 0.024) and CD163 (rpartial = - 0.68, p = 0.029). In sum, CSF Markers for the innate immune system, for neurodegeneration and from lipids were found to be associated with the SQI for response and remission after adjusting for age. Consistently, higher CSF levels of the markers were always associated with lower seizure quality. Based on these results, further research regarding the mechanism of seizure quality in ECT is suggested.

Optimization of Insect Odorant Receptor Trafficking and Functional Expression Via Transient Transfection in HEK293 Cells.

Insect odorant receptors (ORs) show a limited functional expression in various heterologous expression systems including insect and mammalian cells. This may be in part due to the absence of key components driving the release of these proteins from the endoplasmic reticulum and directing them to the plasma membrane. In order to mitigate this problem, we took advantage of small export signals within the human HCN1 and Rhodopsin that have been shown to promote protein release from the endoplasmic reticulum and the trafficking of post-Golgi vesicles, respectively. Moreover, we designed a new vector based on a bidirectional expression cassette to drive the functional expression of the insect odorant receptor coreceptor (Orco) and an odor-binding OR, simultaneously. We show that this new method can be used to reliably express insect ORs in HEK293 cells via transient transfection and that is highly suitable for downstream applications using automated and high-throughput imaging platforms.

Peripheral levels of the anti-aging hormone Klotho in patients with depression.

Klotho is a humoral factor with pleiotropic effects. Most notably, Klotho deficiency is associated with a phenotype comprising organ manifestations accompanying aging including atherosclerosis and cognitive impairment. Research on the role of Klotho in affective disorder is scarce, which is surprising in light of the fact that depression is associated with accelerated cellular aging as well as aging-related phenotypes and comorbidity observed in Klotho deficiency. Soluble α-Klotho (sKlotho) serum levels in patients with a major depressive episode and either undergoing electroconvulsive therapy (n = 16) or a monotherapy with an antidepressant (n = 37) were investigated. We measured the sKlotho serum levels in those patients before and after treatment and compared the baseline levels with those of age-matched healthy controls (n = 39). No group differences were found between the baseline sKlotho levels of patients and controls (573.5 pg/ml vs. 563.8 pg/ml; p = 0.80) and between pre- and post-treatment in the patients with depression (563.8 pg/ml vs. 561.8 pg/ml; p = 0.15), when treated either with electroconvulsive therapy or antidepressant. The major limitation of our study might be that peripheral material such as serum might not reliably reflect processes in the central nervous system. In sum, this first study on peripheral sKlotho levels in a clinical sample cannot confirm a global Klotho dysregulation in depression as it has been already suggested by others. Nonetheless, further preclinical and clinical studies on the involvement of Klotho in affective disorders should be carried out.

Biomarkers for Antidepressant Efficacy of Electroconvulsive Therapy: An Exploratory Cerebrospinal Fluid Study.

BACKGROUND: No candidate biomarkers based on cerebrospinal fluid (CSF) have been identified as prognostic factors in patients with major depression treated with electroconvulsive therapy (ECT), yet. METHOD: Following different underlying hypotheses, we analysed baseline CSF levels of markers of neurodegeneration (tau proteins, ß-amyloids and neurogranin), elements of the innate immune system (interleukin [IL]-6, neopterin, soluble CD14, soluble CD163, migration inhibitory factor and monocyte chemotactic protein 1), endocannabinoids, sphingolipids and Klotho before ECT in patients with depression (n = 12) to identify possible correlations with the clinical antidepressant response to ECT. RESULTS: Correlation with the reduction of the depressive symptoms could be observed especially for markers of neurodegeneration and elements of the innate immune system. Differences for CSF levels of several markers were found between the groups of responders and non-responders at the trend level. LIMITATIONS: The sample size is small and the -distribution of responders and non-responders is uneven. CONCLUSIONS: It is this first study on CSF biomarkers for antidepressant efficacy of ECT warrants further research regarding the mechanism of ECT and personalized antidepressant therapy.

Isolable Cu(I) Complexes of Extremely Electron-Poor, Completely Unreduced o-Quinone and "Di- o-Quinone" Ligands Stabilized through π-π Interactions in the Secondary Coordination Sphere.

The copper-quinone interaction plays important roles in diverse fields such as biochemistry, catalysis, and optically/magnetically switchable materials. Despite this fact, the isolation and thorough characterization of copper(I)-quinone complexes remains a highly challenging task owing to their intrinsic instability. We herein present systems where the stability imparted by the extended π-system of a pyrene ring is used to synthesize, isolate, and crystallographically characterize the first example of a dinuclear metal complex that is bridged by a completely unreduced "di- o-quinone"-type ligand. Additionally, we present the monocopper counterpart with the o-quinone-pyrene type of ligand. The copper complexes are redox-rich and display intriguing electrochemical, optical, and electron paramagnetic resonance (EPR) spectroscopic properties. The line-rich EPR spectra of the one-electron reduced copper(I) complexes were simulated and analyzed via density functional theory calculations. The results presented here establish π-π stacking as a viable alternative to stabilize otherwise unstable redox-active compounds with possible consequences for sensing and redox catalysis.

Uncompleted emergency department care and discharge against medical advice in patients with neurological complaints: a chart review.

BACKGROUND: Uncompleted emergency department care and against-medical-advice discharge represent relevant medical problems with impact on patient safety and potential medicolegal and socioeconomic consequences. They may also indicate structural or procedural problems in the emergency department (ED) relating to patient management and flow. While patients with neurological complaints frequently leave the ED against medical advice or without being seen, no dedicated analysis of this group of patients aiming at the identification of characteristics associated with irregular ED discharge has been performed so far. METHODS: A chart review was performed of all patients with neurological complaints presenting to a German interdisciplinary emergency department between January and December 2017 for neurological evaluation. Demographics, mode of presentation, process times, presenting symptoms and diagnosis were recorded. Patients leaving against medical advice after an informed consent discussion and signing of documentation (DAMA) or leaving prematurely without notifying ED staff (PL) were compared to the total of patients who were admitted or discharged (non-DAMA/PL). RESULTS: Of all patients presenting with neurological symptoms or complaints, 3% left against medical advice and 2.2% left prematurely. DAMA/PL patients were younger (p < .001), and they were more frequently self-presenting (p < 0.001). Headaches, seizures and sensory deficits were the most frequent presenting symptoms in DAMA/PL patients, and 56.1% of those presenting with a seizure had a history of epilepsy. The most common documented reason for leaving was the duration of door-to-doctor time. CONCLUSIONS: Younger age, self-presenting mode of presentation and presentation with headache, seizures or sensory deficits are associated with premature leave or against-medical-advice discharge of patients with neurological complaints from the ED, and long waiting times were given as the major reason for leaving the ED. Increasing ED staff's awareness of these factors and the optimization of pre-hospital assessment and demand management, thereby positively impacting on patient flow and ED process times, may help to prevent irregular discharges from the ED.

A novel Seizure Quality Index based on ictal parameters for optimizing clinical decision making in electroconvulsive therapy. Part 1: development.

Early identification of patients at high risk for an unfavorable outcome to ECT during the course might be beneficial because it provides an opportunity for timely intensification or optimization of stimulus conditions. We aimed to develop a new Seizure Quality Index (SQI) that delivers a clinical relevant outcome prediction early in the treatment course and can be used within common clinical setting. An observational study was conducted. Patients (n = 86) with a depressive episode and the clinical decision for ECT (right unilateral, brief pulse) were included, and several ictal parameters derived from the second ECT session and the clinical outcome of the patients were documented. Optimal cut-off points for five different domains of ictal adequacy for younger and older patients for the prediction of "non-response" and "non-remission" based on seizure quality was determined by the Youden Index and a sum score was built. Logistic regression analyses tested the predictive power of derived models. For both outcome variables "non-response" and "non-remission", the logistic regression models were statistically significant, albeit for remission only for subjects below the age of 65 years (χ2 = 17.9, p = 0.001) and (χ2 = 6.4, p = 0.020), respectively. The models correctly classified 87.2% (non-response) and 50.0% (non-remission) of the cases. ROC curve analysis showed an AUC of 0.87 (non-response) and 0.70 (non-remission). In elderly patients (> 65), no such model could be established due to a response rate of 100%. Our data provide promising, clinically relevant results about the prediction of response to ECT at an early stage for patients with depression.

Impact of pre-admission treatment with non-vitamin K oral anticoagulants on stroke severity in patients with acute ischemic stroke.

BACKGROUND: Non-vitamin K antagonist oral anticoagulants (NOACs) have gained increasing importance for stroke prevention in patients with non-valvular atrial fibrillation (AF). With changing prescription practice, among other factors, clinicians can expect to see rising numbers of patients with ischemic stroke and pre-existing NOAC therapy. Few data exist regarding a potential impact of NOAC on stroke severity and outcome. AIMS: To evaluate the impact of pre-admission NOAC therapy on ischemic stroke severity. METHODS: Retrospective analysis of medical data of 376 patients with newly detected AF or known AF with either no pre-admission oral anticoagulation (n = 277) or existing NOAC therapy (n = 99; Apixaban, n = 33, Dabigatran, n = 16; Edoxaban, n = 1; Rivaroxaban, n = 49) consecutively admitted for acute ischemic stroke between January 2015 and December 2016. RESULTS: Patients with pre-admission NOAC had significantly more often experienced a prior stroke than patients not on NOAC therapy (45.5 vs. 18.4%, p < 0.001) and were significantly more frequently non-smokers (1.0 vs. 7.2%, p = 0.021). Significantly more patients without pre-admission NOAC received thrombolysis (33.8 vs. 8.1%, p < 0.001). Pre-admission NOAC therapy was associated with significantly lower NIHSS and mRS scores upon admission (median NIHSS score 6 vs. 10, p = 0.018, median mRS score 4 vs. 5, p = 0.035) and trend-level lower NIHSS scores at discharge (median NIHSS score 3 vs. 5, p = 0.057). There were no differences regarding the frequency of symptomatic intracerebral hemorrhage between NOAC and non-NOAC patients (p > 0.05). CONCLUSIONS: We report a positive impact of pre-admission NOAC on ischemic stroke severity, which is particularly remarkable in light of the increased prevalence of prior stroke and lower rates of thrombolysis in this patient population.

Heteromultimetallic Complexes with Redox-Active Mesoionic Carbenes: Control of Donor Properties and Redox-Induced Catalysis.

Mesoionic carbenes (MICs) are currently hugely popular as ligands, and triazolylidenes are arguably the most prominent classes of such MICs. Mesoionic carbenes with ferrocenyl substituents are presented that can act as metalloligands for the generation of heteromultimetallic iridium(I) and gold(I) complexes. The ferrocenyl substituents allow for reversible oxidation of these heteromultimetallic complexes, and these oxidation steps have a strong influence on the donor properties of the MICs. Tolman electronic parameters (TEP) determined from analysis of the iridium-carbonyl complexes show that the neutral ferrocenyl-MIC ligands are stronger donors than the imidazolylidene based carbenes, the one-electron oxidized ferrocenyl MICs are in the range of the tricyclohexyl phosphines and the two-electron oxidized forms, which are electron-poor, lie in the range of triphenyl phosphines. Taking advantage of the generation of these electron-poor MICs, we show their gold(I) complexes are potent catalysts for the synthesis of oxazolines, with complexes of the oxidized MIC ligands, without any additional additive, outperforming their neutral counterparts by almost a factor of ten. These results thus present the first examples of MIC ligands that are reversibly electronically tunable, and show the potential of the oxidized MIC ligands in types of catalysis where electron-poor ligands are necessary. The potential of MICs for molecular electroactive materials is also shown.

Electroconvulsive therapy enhances endocannabinoids in the cerebrospinal fluid of patients with major depression: a preliminary prospective study.

Despite the lack of clinical data about the role of the endocannabinoid system (ECS) in affective disorders, preclinical work suggests that the ECS is relevant in both with regard to the etiology of depression as well as the mediation of antidepressant effects. We measured the intraindividual levels of the endocannabinoids N-arachidonoylethanolamine (AEA) and 2-arachidonoylglycerol (2-AG) in the cerebrospinal fluid of 12 patients suffering from a major depressive episode before and after the antidepressant treatment by electroconvulsive therapy (ECT). AEA was significantly elevated after ECT as compared to baseline. The AEA increase positively correlated with the number of individually performed ECT sessions. Although the sample size was small and confounders were not rigorously controlled for, our finding corroborates preclinical work and should encourage further exploration of the involvement of the ECS in depressive disorder.

Electronic Structures and Chiroptical Properties of Post-functionalized Helicene Quinones.

The synthesis of redox-active p- and o-quinones 2-phenylamino-4-phenylimino[6]helicene-1-one 1, 2-phenylamino[6]-helicene-1,4-dione 2, and 4-phenyl[6]helicene-1,2-dione 3 in their enantiopure forms by post-functionalization of (P)- and (M)-1,2-dimethoxy[6]helicene is presented. Structural characterization in solution and in the solid state was accomplished by 2D NMR spectroscopy methods and X-ray diffraction analysis, respectively. Interpretation of electrochemical redox data was accompanied by a detailed orbital picture, derived from DFT calculations. The electronic structures of compounds 1-3 were investigated by UV/Vis and electronic circular dichroism (ECD) spectroscopy, complemented by TD-DFT calculations. Quinones 1-3 were chemically reduced to study the EPR signatures of their respective radical anions. DFT methods were used for the atom assignment of the hyperfine coupling constants. The results are discussed within the context of electrochromic chiral switches and molecular recognition.

Decompressive Hemicraniectomy in Malignant Middle Cerebral Artery Infarction: The 'Real World' Beyond Studies.

BACKGROUND: Decompressive hemicraniectomy (DHC) is life-saving in patients with malignant middle cerebral artery infarction (MMI), but outcome, perspectives and complications after DHC in daily practice are largely unknown. METHODS: From 2008 until 2014, we extracted patient's characteristics as well as complications from our database for patients with MMI who underwent DHC. Additionally, we analysed medical records from the different rehabilitation steps. RESULTS: We identified 48 consecutive patients (mean 57 years, 21 male, 41.7% >60 years) with MMI who underwent DHC. The decision for DHC was made on an individual basis, including patients without impaired consciousness or stroke onset >48 h. In-hospital patients achieved only marginal clinical improvement. Seventy-five percent attended an early-rehabilitation, 44% achieved post-stroke rehabilitation and 6% carried on late-stage rehabilitation. In all, 45.5% returned home after rehabilitation. In-hospital mortality was 14.6%, overall mortality was 16.7%. Surviving patients (78.9%) had a modified Rankin Scale of 4-5. Frequent neurologic complications were symptomatic epilepsy and delirium. Following DHC/bone-flap-reimplantation, wound-healing disorders, epidural hematoma and wound infections were major surgery-related complications. Pulmonary infections were frequent in the acute-phase and urinary tract infections were predominant in the late-phase. CONCLUSIONS: DHC is a life-saving technique in patients with MMI, but complications are frequent, were underestimated in randomized clinical trials and may worsen the functional outcome.

Advantages and challenges of small animal magnetic resonance imaging as a translational tool.

The utilization of magnetic resonance imaging (MRI) methods in rodent models of psychiatric disorders provides considerable benefits for the identification of disease-associated brain circuits and metabolic changes. In this review, we discuss advantages and challenges of animal MRI and provide an overview of the major structural (voxel-based morphometry and diffusion tensor imaging) and functional approaches [resting-state functional MRI (rs-fMRI), MR spectroscopy (MRS), regional cerebral blood volume measurement and arterial spin labelling] that are applied in animal MRI research. The review mainly focuses on rs-fMRI and MRS. Finally, we take a look at some recent developments and refinements in the field.

Impact of the anesthetic agents ketamine, etomidate, thiopental, and propofol on seizure parameters and seizure quality in electroconvulsive therapy: a retrospective study.

In electroconvulsive therapy (ECT), the use of anesthetics without relevant anticonvulsant properties such as ketamine and etomidate may be favorable for seizure quality. Since there is a relative paucity of studies devoted to this issue, our aim was to compare different anesthetics for ECT regarding their impact on seizure quality and different seizure parameters. We retrospectively compared ketamine (n = 912 anesthesias), etomidate (n = 227 anesthesias), thiopental (n = 2,751 anesthesias), and propofol (n = 42 anesthesias) on their influence on general seizure quality and different seizure parameters by multivariate repeated measurement regression analyses. The use of ketamine and etomidate as anesthetics led to seizures that were overall higher in quality and also longer in motor seizure activity when compared to anesthesia with thiopental and propofol. Ketamine was most favorable concerning central inhibitory potential that was indirectly quantified by concordance and postictal suppression. The worst seizure quality was observed with propofol anesthesia; further, this substance had a negative impact on autonomic activation and seizure duration. Based on the data of this retrospective study, the use of ketamine or etomidate as anesthetic in ECT might be advantageous due to the induction of high-quality seizures.

New evidence for seizure quality improvement by hyperoxia and mild hypocapnia.

INTRODUCTION: Preoxygenation and hyperventilation (with oxygen) in electroconvulsive therapy (ECT) may improve not only safety but also seizure quality. METHODS: We retrospectively examined transcutaneous tissue partial pressure of oxygen (tcpO2) and carbon dioxide (tcpCO2) in 441 ECT sessions of 37 consecutive patients. All patients received standard face mask airway management. In parallel, seizure quality markers such as seizure duration, seizure amplitude, central inhibition, interhemispheric coherence, and sympathetic activation were documented and used to build up a seizure quality sum score. RESULTS: Mean (SD) tcpO2 was 289 (123) mm Hg and for tcpCO2 41 (11) mm Hg. A multivariate repeated measurement regression analysis revealed that the ratio of tcpO2/tcpCO2 had a significant influence on the seizure quality sum score (P = 0.033). Furthermore, a corresponding regression analysis with charge ("stimulation energy") as a dependent variable showed a significant influence of tcpO2 (P = 0.019) and of tcpO2/tcpCO2 (P = 0.03), too. CONCLUSIONS: We observed, in our typical clinical ECT sample of 37 patients, a significant and synergistic influence of tcpO2/tcpCO2 on seizure quality. Partial pressure of oxygen covaried with lower stimulation energy. The ratio tcpO2/tcpCO2 was associated with lower stimulation energy and still better seizure quality.

Ultrafast photogeneration of a metal-organic nitrene from 1,1'-diazidoferrocene.

Ferrocene and its derivatives have fascinated chemists for more than 70 years, not least due to the analogies with the properties of benzene. Despite these similarities, the obvious difference between benzene and ferrocene is the presence of an iron ion and hence the availability of d-orbitals for properties and reactivity. Phenylnitrene with its rich photochemistry can be considered an analogue of nitrenoferrocene. As with most organic and inorganic nitrenes, nitrenoferrocene can be obtained by irradiating the azide precursor. We study the photophysical and photochemical processes of dinitrogen release from 1,1'-diazidoferrocene to form 1-azido-1'-nitrenoferrocene with UV-pump-mid-IR-probe transient absorption spectroscopy and time-dependent density functional theory calculations including spin-orbit coupling. An intermediate with a bent azide moiety is identified that is pre-organised for dinitrogen release via a low-lying transition state. The photochemical decay paths on the singlet and triplet surfaces including the importance of spin-orbit coupling are discussed. We compare our findings with the processes discussed for photochemical dinitrogen activation and highlight implications for the photochemistry of azides more generally.