Atomic-scale structure of self-assembled In(Ga)As quantum rings in GaAs

We present an atomic-scale analysis of the indium distribution of self-assembled In(Ga)As quantum rings (QRs) which are formed from InAs quantum dots by capping with a thin layer of GaAs and subsequent annealing. We find that the size and shape of QRs as observed by cross-sectional scanning tunneling microscopy (X-STM) deviate substantially from the ring-shaped islands as observed by atomic force microscopy on the surface of uncapped QR structures. We show unambiguously that X-STM images the remaining quantum dot material whereas the AFM images the erupted quantum dot material. The remaining dot material shows an asymmetric indium-rich crater-like shape with a depression rather than an opening at the center and is responsible for the observed electronic properties of QR structures. These quantum craters have an indium concentration of about 55% and a diameter of about 20 nm which is consistent with the observed electronic radius of QR structures.This work was partially supported by the GOA BOF UA 2000, IUAP, FWO-V projects G.0274.01N, G.0435.03, the WOG WO.035.04N (Belgium), the Spanish MCYT under NANOSELF project TIC2002-04096-C03-03 (Spain), the European Commission GROWTH Programme, NANOMAT project, contract No. G5RD-CT-2001-00545, and the European Commission SANDiE Network of Excellence, contract No. NMP4-CT-2004-500101.Peer reviewe

Boosting the Figure Of Merit of LSPR-based refractive index sensing by phase-sensitive measurements

Localized surface plasmon resonances possess very interesting properties for a wide variety of sensing applications. In many of the existing applications only the intensity of the reflected or transmitted signals is taken into account, while the phase information is ignored. At the center frequency of a (localized) surface plasmon resonance, the electron cloud makes the transition between in- and out-of-phase oscillation with respect to the incident wave. Here we show that this information can experimentally be extracted by performing phase-sensitive measurements, which result in linewidths that are almost one order of magnitude smaller than those for intensity based measurements. As this phase transition is an intrinsic property of a plasmon resonance, this opens up many possibilities for boosting the figure of merit (FOM) of refractive index sensing by taking into account the phase of the plasmon resonance. We experimentally investigated this for two model systems: randomly distributed gold nanodisks and gold nanorings on top of a continuous gold layer and a dielectric spacer and observed FOM values up to 8.3 and 16.5 for the respective nanoparticles

Stomach cancer and occupational exposure to asbestos: a meta-analysis of occupational cohort studies

BACKGROUND: A recent Monographs Working Group of the International Agency for Research on Cancer concluded that there is limited evidence for a causal association between exposure to asbestos and stomach cancer. METHODS: We performed a meta-analysis to quantitatively evaluate this association. Random effects models were used to summarise the relative risks across studies. Sources of heterogeneity were explored through subgroup analyses and meta-regression. RESULTS: We identified 40 mortality cohort studies from 37 separate papers, and cancer incidence data were extracted for 15 separate cohorts from 14 papers. The overall meta-SMR for stomach cancer for total cohort was 1.15 (95% confidence interval 1.03–1.27), with heterogeneous results across studies. Statistically significant excesses were observed in North America and Australia but not in Europe, and for generic asbestos workers and insulators. Meta-SMRs were larger for cohorts reporting a SMR for lung cancer above 2 and cohort sizes below 1000. CONCLUSIONS: Our results support the conclusion by IARC that exposure to asbestos is associated with a moderate increased risk of stomach cancer

Harnessing Wicked Problems in Multi-stakeholder Partnerships

Despite the burgeoning literature on the governance and impact of cross-sector partnerships in the past two decades, the debate on how and when these collaborative arrangements address globally relevant problems and contribute to systemic change remains open. Building upon the notion of wicked problems and the literature on governing such wicked problems, this paper defines harnessing problems in multi-stakeholder partnerships (MSPs) as the approach of taking into account the nature of the problem and of organizing governance processes accordingly. The paper develops an innovative analytical framework that conceptualizes MSPs in terms of three governance processes (deliberation, decision-making and enforce-ment) harnessing three key dimensions of wicked problems (knowledge uncertainty, value conflict and dynamic complexity). The Roundtable on Sustainable Palm Oil provides an illustrative case study on how this analytical framework describes and explains organizational change in partnerships from a problem-based perspective. The framework can be used to better understand and predict the complex relationships between MSP governance processes, systemic change and societal problems, but also as a guiding tool in (re-)organizing governance processes to continuously re-assess the problems over time and address them accordingly

The Aharonov-Bohm effect in self-assembled InGaAs/GaAs quantum rings

Based on the structural information obtained from X-STM measurements, we calculate the electron energy spectra in quantum rings (QR)s and the electron orbital magnetization as a function of the applied magnetic field. Shape anisotropy of QRs results in a mixing of electron states with different magnetic quantum numbers and tends to suppress oscillations of the electron magnetization versus magnetic field. We show that the oscillatory behavior of the average magnetization survives for ensembles of QRs with radial dispersion as large as 10-20%

Effective alcohol policies and lifetime abstinence: An analysis of the International Alcohol Control policy index.

INTRODUCTION: Alcohol abstinence remains common among adults globally, although low and middle-income countries are experiencing declines in abstention. The effect of alcohol policies on lifetime abstinence is poorly understood. The International Alcohol Control (IAC) policy index was developed to benchmark and monitor the uptake of effective alcohol policies and has shown strong associations with alcohol per capita consumption and drinking patterns. Uniquely, the index incorporates both policy 'stringency' and 'impact', reflecting policy implementation and enforcement, across effective policies. Here we assessed the association of the IAC policy index with lifetime abstinence in a diverse sample of jurisdictions. METHODS: We conducted a cross-sectional analysis of the relationship between the IAC policy index score, and its components, and lifetime abstinence among adults (15+ years) in 13 high and middle-income jurisdictions. We examined the correlations for each component of the index and stringency and impact separately. RESULTS: Overall, the total IAC policy index scores were positively correlated with lifetime abstinence (r = 0.76), as were both the stringency (r = 0.62) and impact (r = 0.82) scores. Marketing restrictions showed higher correlations with lifetime abstinence than other policy domains (r = 0.80), including restrictions on physical availability, pricing policies and drink-driving prevention. DISCUSSION AND CONCLUSION: Our findings suggest that restricting alcohol marketing could be an important policy for the protection of alcohol abstention. The IAC policy index may be a useful tool to benchmark the performance of alcohol policy in supporting alcohol abstention in high and middle-income countries

Effective alcohol policies and lifetime abstinence: An analysis of the International Alcohol Control policy index

© 2022 The Authors.Introduction Alcohol abstinence remains common among adults globally, although low and middle-income countries are experiencing declines in abstention. The effect of alcohol policies on lifetime abstinence is poorly understood. The International Alcohol Control (IAC) policy index was developed to benchmark and monitor the uptake of effective alcohol policies and has shown strong associations with alcohol per capita consumption and drinking patterns. Uniquely, the index incorporates both policy ‘stringency’ and ‘impact’, reflecting policy implementation and enforcement, across effective policies. Here we assessed the association of the IAC policy index with lifetime abstinence in a diverse sample of jurisdictions. Methods We conducted a cross-sectional analysis of the relationship between the IAC policy index score, and its components, and lifetime abstinence among adults (15+ years) in 13 high and middle-income jurisdictions. We examined the correlations for each component of the index and stringency and impact separately. Results Overall, the total IAC policy index scores were positively correlated with lifetime abstinence (r = 0.76), as were both the stringency (r = 0.62) and impact (r = 0.82) scores. Marketing restrictions showed higher correlations with lifetime abstinence than other policy domains (r = 0.80), including restrictions on physical availability, pricing policies and drink-driving prevention. Discussion and Conclusion Our findings suggest that restricting alcohol marketing could be an important policy for the protection of alcohol abstention. The IAC policy index may be a useful tool to benchmark the performance of alcohol policy in supporting alcohol abstention in high and middle-income countries

Benchmarking alcohol policy based on stringency and impact: The International Alcohol Control (IAC) policy index.

This study developed a measurement tool to assess stringency and 'on-the-ground' impact of four key alcohol policy domains to create an alcohol policy index suitable for benchmarking alcohol policy and assessing change over time in middle- and high-income countries. It involved a collaboration between researchers in 12 diverse countries: New Zealand; Australia; England; Scotland; Netherlands; Vietnam; Thailand; South Africa; Turkey; Chile; Saint Kitts and Nevis and Mongolia. Data on the four most effective alcohol policy domains (availability, pricing policy, alcohol marketing, drink driving) were used to create an alcohol policy index based on their association with alcohol per capita consumption (APC) of commercial (recorded) alcohol. An innovation was the inclusion of measures of impact along with the stringency of the legislation or regulation. The resulting International Alcohol Control (IAC) Policy Index showed a very high negative correlation (-0.91) with recorded APC. Greater affordability of alcohol, an impact measure taking into account prices paid and countries' Gross Domestic Product, was predictive of higher APC (-0.80). Countries in which more modes of alcohol marketing are legally allowed and used had higher APC. Legislation on outlet density and drink driving predicted APC whereas trading hours did not. While stringency and impact measures varied between domains in terms of relationship with APC, overall, there was a strong correlation between impact and stringency (0.77). The IAC Policy Index, which includes measures of policy stringency and 'on-the-ground' impacts in relation to four key policy areas, was found to be strongly associated with commercial alcohol consumed in a number of diverse country settings. It showed a larger relationship than previous indices that include more policy dimensions. The index provides a relatively simple tool for benchmarking and communication with policy makers to encourage a strong focus on uptake of these four most effective alcohol policies.fals

Artificial intelligence for detection of microsatellite instability in colorectal cancer-a multicentric analysis of a pre-screening tool for clinical application.

BACKGROUND Microsatellite instability (MSI)/mismatch repair deficiency (dMMR) is a key genetic feature which should be tested in every patient with colorectal cancer (CRC) according to medical guidelines. Artificial intelligence (AI) methods can detect MSI/dMMR directly in routine pathology slides, but the test performance has not been systematically investigated with predefined test thresholds. METHOD We trained and validated AI-based MSI/dMMR detectors and evaluated predefined performance metrics using nine patient cohorts of 8343 patients across different countries and ethnicities. RESULTS Classifiers achieved clinical-grade performance, yielding an area under the receiver operating curve (AUROC) of up to 0.96 without using any manual annotations. Subsequently, we show that the AI system can be applied as a rule-out test: by using cohort-specific thresholds, on average 52.73% of tumors in each surgical cohort [total number of MSI/dMMR = 1020, microsatellite stable (MSS)/ proficient mismatch repair (pMMR) = 7323 patients] could be identified as MSS/pMMR with a fixed sensitivity at 95%. In an additional cohort of N = 1530 (MSI/dMMR = 211, MSS/pMMR = 1319) endoscopy biopsy samples, the system achieved an AUROC of 0.89, and the cohort-specific threshold ruled out 44.12% of tumors with a fixed sensitivity at 95%. As a more robust alternative to cohort-specific thresholds, we showed that with a fixed threshold of 0.25 for all the cohorts, we can rule-out 25.51% in surgical specimens and 6.10% in biopsies. INTERPRETATION When applied in a clinical setting, this means that the AI system can rule out MSI/dMMR in a quarter (with global thresholds) or half of all CRC patients (with local fine-tuning), thereby reducing cost and turnaround time for molecular profiling