Nanofriction mechanisms derived from the dependence of friction on load and sliding velocity from air to UHV on hydrophilic silicon

This paper examines friction as a function of the sliding velocity and applied normal load from air to UHV in a scanning force microscope (SFM) experiment in which a sharp silicon tip slides against a flat Si(100) sample. Under ambient conditions, both surfaces are covered by a native oxide, which is hydrophilic. During pump-down in the vacuum chamber housing the SFM, the behavior of friction as a function of the applied normal load and the sliding velocity undergoes a change. By analyzing these changes it is possible to identify three distinct friction regimes with corresponding contact properties: (a) friction dominated by the additional normal forces induced by capillarity due to the presence of thick water films, (b) higher drag force from ordering effects present in thin water layers and (c) low friction due to direct solid-solid contact for the sample with the counterbody. Depending on environmental conditions and the applied normal load, all three mechanisms may be present at one time. Their individual contributions can be identified by investigating the dependence of friction on the applied normal load as well as on the sliding velocity in different pressure regimes, thus providing information about nanoscale friction mechanisms

Violent Behavior During Psychiatric Inpatient Treatment in a German Prison Hospital

Violent behavior in correctional facilities is common and differs substantially in type, target, implication, and trigger. Research on frequency and characteristics of violent behavior in correctional facilities and psychiatric hospitals is limited. Results from recent research suggest that comorbidity of severe mental disorder, personality disorder, and diagnosis of substance abuse is related to a higher risk of violent behavior. In the Berlin prison hospital, a database was created to collect data from all violent incidences (n=210) between 1997 and 2006 and between 2010 and 2016. In a retrospective, case-control study, we analyzed specific socioeconomic data and psychiatric diagnosis and compared the group of prisoners with violent behavior with randomly selected prisoners of the same department without violent behavior (n = 210). Diagnosis of schizophrenia, non-German nationality, no use of an interpreter, no children, and no previous sentence remained significantly associated with the dependent variable violent behavior. There were no significant differences regarding age and legal statuses. Practical implications for clinical work are discussed

Prognostic significance of epithelial-mesenchymal transition in malignant pleural mesothelioma

Background: Epithelial-to-mesenchymal transition (EMT) is a morphologic transdifferentiation of carcinomas, conferring increased tumour invasiveness, but may also be applied to the epithelioid versus sarcomatoid histotype of malignant pleural mesothelioma (MPM). Herein, we correlated proteins of a putative MPM-EMT axis, including periostin, epidermal growth factor receptor (EGFR), integrin beta1, phosphatase and tensin homologue (PTEN), integrin-linked kinase (ILK), p21 and p27, with clinico-pathologic parameters, in particular overall survival (OS). Patients and Methods: A retrospective cohort of 352 mostly untreated patients with MPM was investigated by immunohistochemistry of a tissue microarray. Protein expression intensities were semi-quantitatively scored from 0 to 3 in their respective compartments, including peritumoural stroma as well as tumour cell plasma membrane, cytoplasm or nucleus. Data were correlated with histotype and survival outcome. Results: A total of 32% of the tumours were diagnosed as epithelioid, 13% as sarcomatoid and 55% as biphasic histotype. High expression of membranous EGFR and integrin beta1 as well as nuclear p27 correlated with the epithelioid and high expression of cytoplasmic tumoural and stromal periostin with the sarcomatoid histotype. The median survival time of the 128 patients with complete follow-up data was 11.7 months. Univariate survival analysis revealed age, epithelioid histotype and any therapy as prognosticators for better OS. High expression of cytoplasmic PTEN or ILK as well as high expression of nuclear p21 or p27 correlated with increased, whereas high expression of cytoplasmic periostin with decreased OS (all p values <0.05). Multivariate Cox regression revealed any treatment, low cytoplasmic periostin and high cytoplasmic PTEN as independent prognosticators for better OS. Conclusion: Activation of periostin-triggered EMT is associated with the sarcomatoid histotype and has an impact on shorter survival of MPM patients. Finally, only the high expression of PTEN and the low expression of cytosolic periostin could be shown to be independent prognostic factors for longer O

Smoking prevention intervention with school classes in university hospital by thoracic surgeon und pulmonologist. The Zurich prevention project

Smoking prevention in schoolchildren to inform and prevent smoking initiation has been widely studied; however, the potential effect of interventions provided in a hospital setting is unknown. An intervention program named "Schoolchildren smoking prevention in the hospital" was developed in which the health aspects of smoking and its individual consequences were presented in an interactive informational event provided by a thoracic surgeon and a pulmonologist. We aimed to assess the feasibility and the short-term effect of smoking-related knowledge improvement in schoolchildren in a hospital setting. Scholars of 45 classes in Canton of Zurich in Switzerland filled in an anonymous 5-item questionnaire with questions on general knowledge about smoking. The answers were evaluated in this prospective observational cohort study. The primary endpoint was to compare the knowledge improvement by interpretation of answers before-and-after the smoking prevention intervention. Additionally, the performance of children was compared after setting up an overall score and specific subgroups according to gender and school-level. Between Jan 2010, and Oct 2019, schoolchildren aged 10 to 16 years participated in this intervention program and completed the questionnaire before (N = 1270) and after (N = 1264) the intervention. The amount of correctly answered questions increased from 40% (±20) before to 81% (±17), p < 0·0001 after the educational session. An intervention program on health effects of smoking provided by lung specialists in the hospital is feasible, well received, leads to a substantial increase of knowledge, and hopefully can be further explored in the development of smoking prevention programs for schoolchildren. Keywords: Adolescent; BASEC, Business Administration System for Ethics Committees; CI, Confidence interval; IQR, Interquartile range; OR, Odds radio; RCT, Randomized control trial; SD, Standard deviation; Schoolchildren; Smoking adverse effects; Smoking cessation interventions; Tobacco smoking prevention; i.e, Id est

Searching for targets for the systemic therapy of mesothelioma

Increasing knowledge about the molecular characteristics of mesothelioma had led to the identification of novel potential targets for systemic therapy. This review elaborates on the rationale behind targeted approaches that have been and are undergoing exploration in mesothelioma and summarizes available clinical results and ongoing efforts to improve the systemic therapy of mesotheliom

Cognitive enhancement with Salience Network electrical stimulation is influenced by network structural connectivity

The Salience Network (SN) and its interactions are important for cognitive control. We have previously shown that structural damage to the SN is associated with abnormal functional connectivity between the SN and Default Mode Network (DMN), abnormal DMN deactivation, and impaired response inhibition, which is an important aspect of cognitive control. This suggests that stimulating the SN might enhance cognitive control. Here, we tested whether non-invasive transcranial direct current stimulation (TDCS) could be used to modulate activity within the SN and enhance cognitive control. TDCS was applied to the right inferior frontal gyrus/anterior insula cortex during performance of the Stop Signal Task (SST) and concurrent functional (f)MRI. Anodal TDCS improved response inhibition. Furthermore, stratification of participants based on SN structural connectivity showed that it was an important influence on both behavioural and physiological responses to anodal TDCS. Participants with high fractional anisotropy within the SN showed improved SST performance and increased activation of the SN with anodal TDCS, whilst those with low fractional anisotropy within the SN did not. Cathodal stimulation of the SN produced activation of the right caudate, an effect which was not modulated by SN structural connectivity. Our results show that stimulation targeted to the SN can improve response inhibition, supporting the causal influence of this network on cognitive control and confirming it as a target to produce cognitive enhancement. Our results also highlight the importance of structural connectivity as a modulator of network to TDCS, which should guide the design and interpretation of future stimulation studies

Brain state and polarity dependent modulation of brain networks by transcranial direct current stimulation

Despite its widespread use in cognitive studies, there is still limited understanding of whether and how transcranial direct current stimulation (tDCS) modulates brain network function. To clarify its physiological effects, we assessed brain network function using functional magnetic resonance imaging (fMRI) simultaneously acquired during tDCS stimulation. Cognitive state was manipulated by having subjects perform a Choice Reaction Task or being at “rest.” A novel factorial design was used to assess the effects of brain state and polarity. Anodal and cathodal tDCS were applied to the right inferior frontal gyrus (rIFG), a region involved in controlling activity large‐scale intrinsic connectivity networks during switches of cognitive state. tDCS produced widespread modulation of brain activity in a polarity and brain state dependent manner. In the absence of task, the main effect of tDCS was to accentuate default mode network (DMN) activation and salience network (SN) deactivation. In contrast, during task performance, tDCS increased SN activation. In the absence of task, the main effect of anodal tDCS was more pronounced, whereas cathodal tDCS had a greater effect during task performance. Cathodal tDCS also accentuated the within‐DMN connectivity associated with task performance. There were minimal main effects of stimulation on network connectivity. These results demonstrate that rIFG tDCS can modulate the activity and functional connectivity of large‐scale brain networks involved in cognitive function, in a brain state and polarity dependent manner. This study provides an important insight into mechanisms by which tDCS may modulate cognitive function, and also has implications for the design of future stimulation studies

Statistics of counter-streaming solar wind suprathermal electrons at solar minimum : STEREO observations

Previous work has shown that solar wind suprathermal electrons can display a number of features in terms of their anisotropy. Of importance is the occurrence of counter-streaming electron patterns, i.e., with "beams" both parallel and anti-parallel to the local magnetic field, which is believed to shed light on the heliospheric magnetic field topology. In the present study, we use STEREO data to obtain the statistical properties of counter-streaming suprathermal electrons (CSEs) in the vicinity of corotating interaction regions (CIRs) during the period March–December 2007. Because this period corresponds to a minimum of solar activity, the results are unrelated to the sampling of large-scale coronal mass ejections, which can lead to CSE owing to their closed magnetic field topology. The present study statistically confirms that CSEs are primarily the result of suprathermal electron leakage from the compressed CIR into the upstream regions with the combined occurrence of halo depletion at 90° pitch angle. The occurrence rate of CSE is found to be about 15–20% on average during the period analyzed (depending on the criteria used), but superposed epoch analysis demonstrates that CSEs are preferentially observed both before and after the passage of the stream interface (with peak occurrence rate >35% in the trailing high speed stream), as well as both inside and outside CIRs. The results quantitatively show that CSEs are common in the solar wind during solar minimum, but yet they suggest that such distributions would be much more common if pitch angle scattering were absent. We further argue that (1) the formation of shocks contributes to the occurrence of enhanced counter-streaming sunward-directed fluxes, but does not appear to be a necessary condition, and (2) that the presence of small-scale transients with closed-field topologies likely also contributes to the occurrence of counter-streaming patterns, but only in the slow solar wind prior to CIRs

A comparative investigation of thickness measurements of ultra-thin water films by scanning probe techniques

The reliable operation of micro and nanomechanical devices necessitates a thorough knowledge of the water film thickness present on the surfaces of these devices with an accuracy in the nm range. In this work, the thickness of an ultra-thin water layer was measured by distance tunnelling spectroscopy and distance dynamic force spectroscopy during desorption in an ultra-high vacuum system, from about 2.5 nm up to complete desorption at 1E-8 mbar. The tunnelling current as well as the amplitude of vibration and the normal force were detected as a function of the probe-sample distance. In these experiments, a direct conversion of the results of both methods is possible. From the standpoint of surface science, taking the state-of-the-art concerning adsorbates on surfaces into consideration, dynamic force spectroscopy provides the most accurate values. The previously reported tunnelling spectroscopy, requiring the application of significantly high voltages, generally leads to values that are 25 times higher than values determined by dynamic force spectroscopy