Stability of sub-surface oxygen at Rh(111)

Using density-functional theory (DFT) we investigate the incorporation of oxygen directly below the Rh(111) surface. We show that oxygen incorporation will only commence after nearly completion of a dense O adlayer (\theta_tot = 1.0 monolayer) with O in the fcc on-surface sites. The experimentally suggested octahedral sub-surface site occupancy, inducing a site-switch of the on-surface species from fcc to hcp sites, is indeed found to be a rather low energy structure. Our results indicate that at even higher coverages oxygen incorporation is followed by oxygen agglomeration in two-dimensional sub-surface islands directly below the first metal layer. Inside these islands, the metastable hcp/octahedral (on-surface/sub-surface) site combination will undergo a barrierless displacement, introducing a stacking fault of the first metal layer with respect to the underlying substrate and leading to a stable fcc/tetrahedral site occupation. We suggest that these elementary steps, namely, oxygen incorporation, aggregation into sub-surface islands and destabilization of the metal surface may be more general and precede the formation of a surface oxide at close-packed late transition metal surfaces.Comment: 9 pages including 9 figure files. Submitted to Phys. Rev. B. Related publications can be found at http://www.fhi-berlin.mpg.de/th/paper.htm

Preconditioning triggered by carbon monoxide (CO) provides neuronal protection following perinatal hypoxia-ischemia

Perinatal hypoxia-ischemia is a major cause of acute mortality in newborns and cognitive and motor impairments in children. Cerebral hypoxia-ischemia leads to excitotoxicity and necrotic and apoptotic cell death, in which mitochondria play a major role. Increased resistance against major damage can be achieved by preconditioning triggered by subtle insults. CO, a toxic molecule that is also generated endogenously, may have a role in preconditioning as low doses can protect against inflammation and apoptosis. In this study, the role of CO-induced preconditioning on neurons was addressed in vitro and in vivo. The effect of 1 h of CO treatment on neuronal death (plasmatic membrane permeabilization and chromatin condensation) and bcl-2 expression was studied in cerebellar granule cells undergoing to glutamate-induced apoptosis. CO's role was studied in vivo in the Rice-Vannucci model of neonatal hypoxia-ischemia (common carotid artery ligature +75 min at 8% oxygen). Apoptotic cells, assessed by Nissl staining were counted with a stereological approach and cleaved caspase 3-positive profiles in the hippocampus were assessed. Apoptotic hallmarks were analyzed in hippocampal extracts by Western Blot. CO inhibited excitotoxicity-induced cell death and increased Bcl-2 mRNA in primary cultures of neurons. In vivo, CO prevented hypoxia-ischemia induced apoptosis in the hippocampus, limited cytochrome c released from mitochondria and reduced activation of caspase-3. Still, Bcl-2 protein levels were higher in hippocampus of CO pre-treated rat pups. Our results show that CO preconditioning elicits a molecular cascade that limits neuronal apoptosis. This could represent an innovative therapeutic strategy for high-risk cerebral hypoxia-ischemia patients, in particular neonates

Prevalence of late and long-term effects of cancer (treatment) and use of complementary and alternative medicine in Norway

Background The increasing number of patients surviving cancer leads to more people experiencing late and long term-effects from the disease and its treatment. Fatigue, sleep disorders, early menopause, pain, and nerve damage are commonly reported. Methods helping people to recover after cancer treatment are therefore essential. The aims of this study were threefold; (1) to determine the level of cancer patients suffering from late and long-term effects of cancer diagnosis and treatment in Norway, (2) explore complementary and alternative medicine (CAM) modalities used for managing these adversities, and (3) describe self-perceived benefits and harms of the CAM interventions. Methods The study was conducted in cooperation with the Norwegian Cancer Society (NCS) and consisted of an online cross-sectional study among members of the NCS user panel with present or previous cancer (n = 706). The study was carried out in September/October 2021 using a modified cancer-specific version of the International Questionnaire to Measure Use of Complementary and Alternative Medicine (I-CAM-Q). A total of 315 women and 153 men agreed to participate, resulting in a response rate of 67%. Results Most of the participants (83%) suffered from late and long-term effects of cancer treatment; mostly fatigue (59.2%), sleep disorder (41.5%), hot flashes (39.2%), nerve damage (polyneuropathy, 38.0%), and pain (36.6%) with a mean number of 5.1 different late and long-term effects. Late and long-term effects were positively associated with younger age and college/university education. Nearly half of the participants experiencing late and long-term effects (43%) reported having used CAM to treat these complaints. Most frequently used were self-help practices (26%) such as relaxation therapy (19%), yoga (14%) and meditation (13%), but also visits to CAM providers were reported by 22%. Herbal- and other natural remedies to treat late and long-term effects were used by 13%. A high percentage of CAM users reported self-perceived improvements of their symptoms (86% for self-help practices, 90% for visits to CAM providers). Few experienced adverse effects of the CAM treatment. Conclusion A large proportion of cancer patients suffered from a wide range of late and long-term effects of cancer diagnosis and treatment, and they use CAM to treat these complaints to a rather high degree. Relaxation therapy, yoga, meditation, massage, and acupuncture were the most frequently used therapies regardless of complaint. The therapies used are generally considered to be both safe and beneficial for the respective complaint, indicating that the participants seem to be well informed about the choices they make

Administration of Intranasal Insulin During Cardiopulmonary Resuscitation Improves Neurological Outcomes After Cardiac Arrest

INTRODUCTION: Over 325,000 people die from cardiac arrest each year. Prognosis is poor and survivors typically experience persistent neurologic deficits. Currently, neuroprotective treatments to reduce brain injury in cardiac arrest survivors are limited and ineffective. This study evaluates the potential neuroprotection induced by high dose intranasal insulin (HD-IN-I) in a rodent model of asphyxial cardiac arrest. METHODS: Male Long Evans rats were block randomized to sham-operated controls or 8-minute asphyxial cardiac arrest treated with placebo or HD-IN-I at the onset of CPR. To investigate mechanism of action, hippocampi were collected 30 minutes post-ROSC and analyzed by Western blot for phosphorylation of Akt. To assess long-term functional outcomes, neurobehavioral evaluation was conducted using neurologic function scores daily and Barnes maze, Rotarod, and passive avoidance on days 7-10 post-ROSC. Histologic quantification of surviving hippocampal CA1 pyramidal neurons was also conducted. RESULTS: Hippocampal phospho-Akt/total Akt ratio increased 2-fold in the placebo group and 5.7-fold in HD-IN-I group relative to shams (p \u3c 0.05). Rats treated with HD-IN-I had significantly improved performance on Rotarod, Barnes maze, and passive avoidance (p \u3c 0.05). HD-IN-I had no significant effect on ROSC rate, 10-day survival, systemic glycemic response, or on the number of surviving CA1 pyramidal neurons compared to placebo treatment. DISCUSSION: This study is the first to demonstrate that HD-IN-I administered at the onset of CPR, causes phosphorylation of brain Akt and results in significant neuroprotection. This primary work strongly suggests that intranasal insulin could be the first highly effective neuroprotective treatment for cardiac arrest patients

Differential Photoelectron Holography: A New Approach for Three-Dimensional Atomic Imaging

We propose differential holography as a method to overcome the long-standing forward-scattering problem in photoelectron holography and related techniques for the three-dimensional imaging of atoms. Atomic images reconstructed from experimental and theoretical Cu 3p holograms from Cu(001) demonstrate that this method suppresses strong forward-scattering effects so as to yield more accurate three-dimensional images of side- and back-scattering atoms.Comment: revtex, 4 pages, 2 figure

Longitudinal exchange: an alternative strategy towards quantification of dynamics parameters in ZZ exchange spectroscopy

Longitudinal exchange experiments facilitate the quantification of the rates of interconversion between the exchanging species, along with their longitudinal relaxation rates, by analyzing the time-dependence of direct correlation and exchange cross peaks. Here we present a simple and robust alternative to this strategy, which is based on the combination of two complementary experiments, one with and one without resolving exchange cross peaks. We show that by combining the two data sets systematic errors that are caused by differential line-broadening of the exchanging species are avoided and reliable quantification of kinetic and relaxation parameters in the presence of additional conformational exchange on the ms–μs time scale is possible. The strategy is applied to a bistable DNA oligomer that displays different line-broadening in the two exchanging species

PepShell : visualization of conformational proteomics data

Proteins are dynamic molecules; they undergo crucial conformational changes induced by post-translational modifications and by binding of cofactors or other molecules. The characterization of these conformational changes and their relation to protein function is a central goal of structural biology. Unfortunately, most conventional methods to obtain structural information do not provide information on protein dynamics. Therefore, mass spectrometry-based approaches, such as limited proteolysis, hydrogen-deuterium exchange, and stable-isotope labeling, are frequently used to characterize protein conformation and dynamics, yet the interpretation of these data can be cumbersome and time consuming. Here, we present PepShell, a tool that allows interactive data analysis of mass spectrometry-based conformational proteomics studies by visualization of the identified peptides both at the sequence and structure levels. Moreover, PepShell allows the comparison of experiments under different conditions, including different proteolysis times or binding of the protein to different substrates or inhibitors

NMR-Based Prostate Cancer Metabolomics

Author's accepted version (postprint).This is an Accepted Manuscript of an article published by Springer in Methods in Molecular Biology on 22 May 2018.Available online: https://doi.org/10.1007/978-1-4939-7845-8_14acceptedVersio