Sediment type unsupervised classification of the Molenplaat, Westerschelde estuary, The Netherlands

Sediment stability or erosion resistance of intertidal zones depend on sediment physical characteristics and on biological factors. Obtaining accurate data on the basic biological, chemical and physical processes in sediments is expensive and difficult. Remote sensing methods can produce detailed information on ecological functioning in a cost-effective manner. A hyperspectral image of the Molenplaat, an intertidal flat in the Westerschelde estuary, the Netherlands, was acquired with the HyMap sensor in June 2004. The goal of this research is to perform, analyse and evaluate unsupervised classification methods for sediment types on the imagery. The unsupervised methods are based on Principal Component Analysis (PCA) or Iterative Self-Organizing Data Analysis Technique (ISODATA), and consist of three steps: (a) classification into spectrally distinct clusters, (b) post-clustering treatment, and (c) assignment of labels to the clusters. The result consists of 13 clusters after the post-clustering treatment, and of 8 or 9 classes after labelling for either the PCA or ISODATA method. A supervised Spectral Angle Mapper (SAM) classification was performed using field data to evaluate the unsupervised classification results. The labelling of the unsupervised clusters was also partly based on the SAM results, due to limited field data.The comparison of the results reveals that 69% and 73% of the pixels of PCA and ISODATA classification respectively were identically labelled in the supervised classification. Moreover, the mismatches were mainly found in two classes, while the other classes showed high similarities, indicating the plausibility of using unsupervised classification methods for intertidal sediment types. Additional strengths of the unsupervised classification methods are (a) the distinction of classes that were not visited during field work and not classified in the supervised classification, (b) the identification of spectrally distinct areas that should be characterised during field campaigns, and (c) the user-friendliness thanks to limited required field knowledge and short calculation time

TideSed: intertidal sediment characterization using HyMap imagery

The Scheldt Estuary is internationally known for its nature and as an important commercial shipping route. Obtaining accurate data on the basic biological, chemical and physical processes in intertidal sediments is expensive and difficult: the accessibility to the site is limited, and estuaries are characterized by a wide spatial heterogeneity. Remote sensing methods can produce detailed information on intertidal sediments in a cost-effective manner. Hyperspectral HyMap imagery is combined with intensive ground truthing to quantify the most important biological and physical parameters. To achieve these goals a consortium consisting of five research institutes with complementary skills in remote sensing, marine (and coastal zone) ecology and sediment mechanics, joined forces in the TIDESED project

Ploidy of Cell-Sorted Trophic and Cystic Forms of Pneumocystis carinii

Once regarded as an AIDS-defining illness, Pneumocystis pneumonia (PcP) is nowadays prevailing in immunocompromised HIV-negative individuals such as patients receiving immunosuppressive therapies or affected by primary immunodeficiency. Moreover, Pneumocystis clinical spectrum is broadening to non-severely-immunocompromised subjects who could be colonized by the fungus while remaining asymptomatic for PcP, thus being able to transmit the infection by airborne route to susceptible hosts. Although the taxonomical position of the Pneumocystis genus has been clarified, several aspects of its life cycle remain elusive such as its mode of proliferation within the alveolus or its ploidy level. As no long-term culture model exists to grow Pneumocystis organisms in vitro, an option was to use a model of immunosuppressed rat infected with Pneumocystis carinii and sort life cycle stage fractions using a high-through-put cytometer. Subsequently, ploidy levels of the P. carinii trophic and cystic form fractions were measured by flow cytometry. In the cystic form, eight contents of DNA were measured thus strengthening the fact that each mature cyst contains eight haploid spores. Following release, each spore evolves into a trophic form. The majority of the trophic form fraction was haploid in our study. Some less abundant trophic forms displayed two contents of DNA indicating that they could undergo (i) mating/fusion leading to a diploid status or (ii) asexual mitotic division or (iii) both. Even less abundant trophic forms with four contents of DNA were suggestive of mitotic divisions occurring following mating in diploid trophic forms. Of interest, was the presence of trophic forms with three contents of DNA, an unusual finding that could be related to asymmetrical mitotic divisions occurring in other fungal species to create genetic diversity at lower energetic expenses than mating. Overall, ploidy data of P. carinii life cycle stages shed new light on the complexity of its modes of proliferation

Oblivious Pseudorandom Functions from Isogenies

An oblivious PRF, or OPRF, is a protocol between a client and a server, where the server has a key $k$ for a secure pseudorandom function $F$, and the client has an input $x$ for the function. At the end of the protocol the client learns $F(k,x)$, and nothing else, and the server learns nothing. An OPRF is verifiable if the client is convinced that the server has evaluated the PRF correctly with respect to a prior commitment to $k$. OPRFs and verifiable OPRFs have numerous applications, such as private-set-intersection protocols, password-based key-exchange protocols, and defense against denial-of-service attacks. Existing OPRF constructions use RSA-, Diffie-Hellman-, and lattice-type assumptions. The first two are not post-quantum secure. In this paper we construct OPRFs and verifiable OPRFs from isogenies. Our main construction uses isogenies of supersingular elliptic curves over $\mathbb{F}_{p^{2}}$ and tries to adapt the Diffie-Hellman OPRF to that setting. However, a recent attack on supersingular-isogeny systems due to Galbraith et al. [ASIACRYPT 2016] makes this approach difficult to secure. To overcome this attack, and to validate the server\u27s response, we develop two new zero-knowledge protocols that convince each party that its peer has sent valid messages. With these protocols in place, we obtain an OPRF in the SIDH setting and prove its security in the UC framework. Our second construction is an adaptation of the Naor-Reingold PRF to commutative group actions. Combining it with recent constructions of oblivious transfer from isogenies, we obtain an OPRF in the CSIDH setting

Le loxoscelisme cutané, à propos d’une observation exceptionnelle de 9 cas consécutifs

International audienceINTRODUCTION:Loxosceles spiders are ubiquitous and responsible for many cases of envenomation in the world. The kind rufescens is present in the Provence and Occitan regions in France. During the summer 2015, we faced many Loxosceles rufescens cases of bites having led to extensive integumental necrosis whose features and singular evolution seems important to report.MATERIAL AND METHODS:We report the cases of nine patients who experienced a spider bite in the summer of 2015 in the Languedoc Roussillon.RESULTS:Of nine patients, eight patients had skin necrosis and five required surgical care. Five patients had a fever and had five other general signs such as important asthenia, joint pain, nausea and dizziness. CRP was very low normal in all patients. Finally, five of the nine patients reported a residual pain.DISCUSSION:L. rufescens is a small spider (7 to 15mm in diameter) having a cytotoxic venom. Loxoscelism diagnosis is usually made by removing a front necrotic skin lesion. Of systemic loxoscelism that have been described, some American species had fatal outcomes. The treatment remains controversial with various options: surgery, antibiotics, antihistaminics, antivenom.CONCLUSION:The diagnosis must be made in endemic areas when confronted to a necrosic integumentary infectious rapidly progressive, unresponsive to antibiotic treatment associated with atypical general signs

Anti-Saccharomyces cerevisiae antibodies in twins with inflammatory bowel disease

Background and aims: An increased occurrence of anti-Saccharomyces cerevisiae antibodies (ASCA) is reported in unaffected members of families with Crohn’s disease. Whether ASCA is a familial trait due to genetic factors or is caused by exposure to environmental factors is unknown. To assess the genetic influence of ASCA we studied its occurrence in a twin population. Patients and methods: ASCA were analysed in 98 twin pairs with inflammatory bowel disease and were related to clinical phenotype and CARD15/NOD2 genotype. Results: ASCA were more common in Crohn’s disease than in ulcerative colitis (40/70 (57%) twins v 5/43 (12%) twins). Associations with ileal Crohn’s disease, stricturing/penetrating behaviour, and young age, but not CARD15/NOD2 were confirmed. ASCA were found in 1/20 (5%) healthy siblings in discordant monozygotic pairs with Crohn’s disease compared with 7/27 (26%) in discordant dizygotic pairs. Using the intraclass correlation coefficient (ICC), no agreement in ASCA titres was observed in discordant twin pairs with Crohn’s disease, in monozygotic (ICC = −0.02) or dizygotic (ICC = −0.26) pairs. In contrast, strong agreement was seen within concordant monozygotic twin pairs with Crohn’s disease (ICC = 0.76). Conclusions: These findings question the concept of ASCA as a marker of genetic susceptibility for Crohn’s disease. The agreement in ASCA titres within concordant monozygotic twin pairs with Crohn’s disease, suggests that the level of increase is genetically determined. We propose that ASCA are a marker of a response to an environmental antigen and that a specific gene(s) other than CARD15/NOD2 determines the level of response and perhaps also specific phenotypic characteristics

A phase I trial assessing the safety, pharmacokinetics, cerebrospinal fluid penetrance, and food effect of BTK inhibitor tolebrutinib in healthy volunteers

Abstract Tolebrutinib is an oral, brain‐penetrant, covalent Bruton's tyrosine kinase inhibitor in development to treat multiple sclerosis at 60 mg/day with food. A phase I trial was conducted in healthy volunteers to assess the safety and pharmacokinetics of tolebrutinib at oral doses higher than 60 mg with food and during fasting, and to determine cerebrospinal fluid (CSF) exposure after a single dose of 60 or 120 mg with food. The trial included double‐blind, placebo‐controlled single ascending dose (120, 240, and 300 mg; fed and fasted) and multiple ascending dose (120, 180, and 240 mg) arms. Additional open‐label cohorts received a single 60 mg dose with a high‐fat meal and during fasting using a crossover design or a single 60 or 120 mg dose with food and lumbar puncture to obtain CSF. Tolebrutinib was rapidly absorbed and converted to an active metabolite (designated “M2”), both of which had a terminal half‐life of ~5 h. Tolebrutinib and M2 exposures increased following administration with food versus fasting, and plasma levels were generally dose proportional. For up to 4 h (the last measurement timepoint) after a 60 mg dose, CSF concentrations of tolebrutinib exceeded its in vitro cellular potency (half‐maximal inhibitory concentration [IC50]) for microglia, and tolebrutinib and M2 surpassed their biochemical IC50. Tolebrutinib was well‐tolerated, and treatment‐emergent adverse events were generally mild. Concentration‐QTc modeling showed no effects on QT/QTc intervals for any tolebrutinib dose or fed status. In conclusion, tolebrutinib has an acceptable safety profile at supratherapeutic doses and achieved bioactive CSF exposures at the phase III dose