Surface-induced charge state conversion of nitrogen-vacancy defects in nanodiamonds

We present a study of the charge state conversion of single nitrogen-vacancy (NV) defects hosted in nanodiamonds (NDs). We first show that the proportion of negatively-charged NV$^{-}$ defects, with respect to its neutral counterpart NV$^{0}$, decreases with the size of the ND. We then propose a simple model based on a layer of electron traps located at the ND surface which is in good agreement with the recorded statistics. By using thermal oxidation to remove the shell of amorphous carbon around the NDs, we demonstrate a significant increase of the proportion of NV$^{-}$ defects in 10-nm NDs. These results are invaluable for further understanding, control and use of the unique properties of negatively-charged NV defects in diamondComment: 6 pages, 4 figure

Treatment of liver fibrosis: Clinical aspects

SummaryThe main objective of antifibrotic treatment is to avoid the complications of chronic liver disease where its cause cannot be treated. Three main therapeutic endpoints can be targeted: cause; comorbidity; and fibrosis. Antifibrotic treatment is any intervention independent of cause that is intended to modify the course and/or level of fibrosis through direct action on the mechanisms of fibrosis. Several modalities are here considered: reduction of fibrosis course; reversion of fibrosis; and reversion of cirrhosis. Semiquantitative histological staging and morphometry are complementary techniques for monitoring fibrosis. The degree of fibrosis should preferentially be estimated by fibrosis progression based on measurements taken at baseline and during treatment, rather than by raw static measurements. Surrogate markers are the only tools for assessing drug efficacy in clinical practice, and are especially useful for checking compliance and identifying poor or non-responders. We propose to define non-response as no decrease in fibrosis progression. The renin–angiotensin system is a good candidate target for antifibrotic treatment, and angiotensin-II type-1 receptor blockers, such as sartans, are probably effective. Clinical trials are currently ongoing using marketed drugs, while new multitargeted drugs are likely to emerge from basic research

Non-invasive diagnosis of liver lesions by blood tests in NAFLD

Background and Aims: Non invasive tests are not well developedin NAFLD. This could be partly due to the pathological description of certain lesions that is hampered by semi-quantitative scorings. Our aim was to develop an accurate non-invasive measurement of main liver lesions in NAFLD by blood tests based on a thorough pathological and morphometric analysis. Methods: Steatosis, NASH and fibrosis were graded according to CRN-NASH (Kleiner, Hepatology 2005) and Metavir systems in 226 patients with NAFLD. A fully automated, in-house software measured the fractal dimension (reflecting architecture) and the area (reflecting amount) of steatosis or fibrosis on liver specimens. Independent predictors were selected by logistic or multiple regression repeated in 1000 random bootstrap samples. When models were determined, a second bootstrap resampling was performed to measure optimism bias (Steyerberg et al. 2001)

Light depolarization effects in tip enhanced Raman spectroscopy of silicon (001) and gallium arsenide (001)

We report on the effects of light depolarization induced by sharp metallic tips in Tip-Enhanced Raman Spectroscopy (TERS). Experiments on Si(001) and GaAs(001) crystals show that the excitation field depolarization induces a selective enhancement of specific Raman modes, depending on their Raman tensor symmetry. A complete polarization analysis of the light backscattered from the tip confirms the TERS findings. The spatial confinement of the depolarization field is studied and its dependence on the excitation wavelength and power are explored

Feature integration in natural language concepts

Two experiments measured the joint influence of three key sets of semantic features on the frequency with which artifacts (Experiment 1) or plants and creatures (Experiment 2) were categorized in familiar categories. For artifacts, current function outweighed both originally intended function and current appearance. For biological kinds, appearance and behavior, an inner biological function, and appearance and behavior of offspring all had similarly strong effects on categorization. The data were analyzed to determine whether an independent cue model or an interactive model best accounted for how the effects of the three feature sets combined. Feature integration was found to be additive for artifacts but interactive for biological kinds. In keeping with this, membership in contrasting artifact categories tended to be superadditive, indicating overlapping categories, whereas for biological kinds, it was subadditive, indicating conceptual gaps between categories. It is argued that the results underline a key domain difference between artifact and biological concepts

Survey data of public awareness on climate change and the value of marine and coastal ecosystems

The long-term provision of ocean ecosystem services depends on healthy ecosystems and effective sustainable management. Understanding public opinion about marine and coastal ecosystems is important to guide decision-making and inform specific actions. However, available data on public perceptions on the interlinked effects of climate change, human impacts and the value and management of marine and coastal ecosystems are rare. This dataset presents raw data from an online, self-administered, public awareness survey conducted between November 2021 and February 2022 which yielded 709 responses from 42 countries. The survey was released in four languages (English, French, Spanish and Italian) and consisted of four main parts: (1) perceptions about climate change; (2) perceptions about the value of, and threats to, coasts, oceans and their wildlife, (3) perceptions about climate change response; and (4) socio-demographic information. Participation in the survey was voluntary and all respondents provided informed consent after reading a participant information form at the beginning of the survey. Responses were anonymous unless respondents chose to provide contact information. All identifying information has been removed from the dataset. The dataset can be used to conduct quantitative analyses, especially in the area of public perceptions of the interlinkages between climate change, human impacts and options for sustainable management in the context of marine and coastal ecosystems. The dataset is provided with this article, including a copy of the survey and participant information forms in all four languages, data and the corresponding codebook.This study received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement MaCoBioS (No 869710). The funders had no role in any part of the research process.info:eu-repo/semantics/publishedVersio

Hydrostatic strain enhancement in laterally confined SiGe nanostripes

Strain-engineering in SiGe nanostructures is fundamental for the design of optoelectronic devices at the nanoscale. Here we explore a new strategy, where SiGe structures are laterally confined by the Si substrate, to obtain high tensile strain avoiding the use of external stressors, and thus improving the scalability. Spectro-microscopy techniques, finite element method simulations and ab initio calculations are used to investigate the strain state of laterally confined Ge-rich SiGe nano-stripes. Strain information is obtained by tip enhanced Raman spectroscopy with an unprecedented lateral resolution of ~ 30 nm. The nano-stripes exhibit a large tensile hydrostatic strain component, which is maximum at the center of the top free surface, and becomes very small at the edges. The maximum lattice deformation is larger than the typical values of thermally relaxed Ge/Si(001) layers. This strain enhancement originates from a frustrated relaxation in the out-of-plane direction, resulting from the combination of the lateral confinement induced by the substrate side walls and the plastic relaxation of the misfit strain in the (001) plane at the SiGe/Si interface. The effect of this tensile lattice deformation at the stripe surface is probed by work function mapping, performed with a spatial resolution better than 100 nm using X-ray photoelectron emission microscopy. The nano-stripes exhibit a positive work function shift with respect to a bulk SiGe alloy, quantitatively confirmed by electronic structure calculations of tensile strained configurations. The present results have a potential impact on the design of optoelectronic devices at a nanometer length scale.Comment: 40 pages, 11 figures, submitted to Physical Review

Quantification of portal–bridging fibrosis area more accurately reflects fibrosis stage and liver stiffness than whole fibrosis or perisinusoidal fibrosis areas in chronic hepatitis C

International audienceMorphometry provides an objective evaluation of fibrosis in liver diseases. We developed an image analysis algorithm using automated thresholding and segmentation to separately quantify the areas and the fractal dimensions of portal–bridging fibrosis and perisinusoidal fibrosis in chronic hepatitis C liver biopsies. We studied 427 digitized liver biopsies and compared the automated measures of the different fibrosis compartments with (1) the Metavir F (fibrosis) and A (activity) histological scores, (2) the digitally assessed area of steatosis, and (3) the liver stiffness measured by elastography (Fibroscan). The perisinusoidal fibrosis area was higher than that of portal fibrosis in stages ≤F2; it reached its highest value in F2 stage and stabilized thereafter. The F3 stage was characterized by equal proportions of portal–bridging and perisinusoidal fibrosis, whereas portal–bridging area was predominant in cirrhosis. Measurement of portal–bridging fibrosis showed highly significantly different values between contiguous F stages; the ratio of portal–bridging fibrosis/perisinusoidal fibrosis displayed less overlap between Metavir stages than did the whole fibrosis area values. Fractal dimension showed that portal–bridging fibrosis tended to display a homogeneous surface-like spatial organization, whereas perisinusoidal fibrosis appeared more heterogeneous according to stage and curvilinear. The portal–bridging fibrosis area was low in cases with low Metavir activity and little steatosis, and became predominant with increasing activity and steatosis. Using stepwise multiple linear regression analysis, the liver stiffness was independently correlated to the portal–bridging fibrosis area (first step, P<0.001), the steatosis area (second step, P<0.001), and the Metavir A grade (third step, P=0.001), but not to the perisinusoidal fibrosis area. Automated quantification in a large cohort of chronic hepatitis C showed that perisinusoidal fibrosis progressively grew in early fibrosis stages but did not increase in septal or cirrhotic stages and that the portal–bridging fibrosis area appeared as a more accurate tool to assess fibrosis progression than the whole fibrosis area

Fibrosis progression under maintenance interferon in hepatitis C is better detected by blood test than liver morphometry

Summary.  We evaluated whether quantitative measurements of liver fibrosis with recently developed diagnostics outperform histological staging in detecting natural or interferon-induced changes. We compared Metavir staging, morphometry (area and fractal dimension) and six blood tests in 157 patients with chronic hepatitis C from two trials testing maintenance interferon for 96 weeks. Paired liver biopsies and blood tests were available for 101 patients, and there was a significant improvement in Metavir activity and a significant increase in blood tests reflecting fibrosis quantity in patients treated with interferon when compared with controls – all per cent changes in histological fibrosis measures were significantly increased in F1 vs F2–4 stages only in the interferon group. For the whole population studied between weeks 0 and 96, there was significant progression only in the area of fibrosis (AOF) (P = 0.026), FibroMeter (P = 0.020) and CirrhoMeter (P = 0.003). With regards to dynamic reproducibility, agreement was good (ric ≥ 0.72) only for Metavir fibrosis score, FibroMeter and CirrhoMeter. The per cent change in AOF was significantly higher than that of fractal dimension (P = 0.003) or Metavir fibrosis score (P = 0.015). CirrhoMeter was the only blood test with a change significantly higher than that of AOF (P = 0.039). AOF and two blood tests, reflecting fibrosis quantity, have high sensitivity and/or reproducibility permitting the detection of a small progression in liver fibrosis over two years. A blood test reflecting fibrosis quantity is more sensitive and reproducible than morphometry. The study also shows that maintenance interferon does not improve fibrosis, whatever its stage