The Role Of Reputation In Market Entry: Evidence From French Public Procurement

This article studies the impact of reputation on market entry in public procurement. Based on the observation of a French firm with a strong reputation, we demonstrate a significant effect of the difference in public contracts won between date t-1 and date t. Our model provides empirical proof that selection of a supplier with a strong reputation does not hinder entry in public procurement nor does it prevent free competition. This result thus questions the justification for the European Union regulation that limits the use of information on past performance to select suppliers in public markets. The findings also suggest that reputation mechanisms can help reduce uncertainty during contract execution.

Zr and Hf microalloying in an Al-Y-Fe amorphous alloy. Relation between local structure and glass-forming ability

International audienceThe effects of the addition of small amounts of Zr and Hf (0.5 - 3 %) on the atomic structure of Al88Y7Fe5 metallic glass were examined from extended x-ray absorption fine structure (EXAFS) experiments to better understand the influence of these microadditions on the glass forming ability of this alloy. Measurements at the Zr K and Hf LIII absorption edges have allowed the local structures around Zr and Hf atoms to be determined. The same Al environment was found for the different concentrations, consisting of a small cluster extending up to 4.5 Å around the Zr atoms and up to 6 Å around the Hf ones. Although the clustering effect is smaller in the Zr neighbourhood, a drastic shortening of the nearest Zr-Al distance is shown, providing evidence for some covalent character to the bonding, in line with the increased glass-forming ability found in the alloys made with the Zr microaddition

Preferential MGMT hypermethylation in SDH-deficient wild-type GIST

AIMS: Wild-type gastrointestinal stromal tumours (wtGIST) are frequently caused by inherited pathogenic variants, or somatic alterations in the succinate dehydrogenase subunit genes (SDHx). Succinate dehydrogenase is a key enzyme in the citric acid cycle. SDH deficiency caused by SDHx inactivation leads to an accumulation of succinate, which inhibits DNA and histone demethylase enzymes, resulting in global hypermethylation. Epigenetic silencing of the DNA repair gene MGMT has proven utility as a positive predictor of the therapeutic efficacy of the alklyating drug temozolomide (TMZ) in tumours such as glioblastoma multiforme. The aim of this study was to examine MGMT promoter methylation status in a large cohort of GIST. METHODS: MGMT methylation analysis was performed on 65 tumour samples including 47 wtGIST (33 SDH-deficient wtGIST and 11 SDH preserved wtGIST) and 21 tyrosine kinase (TK) mutant GIST. RESULTS: MGMT promoter methylation was detected in 8 cases of SDH-deficient (dSDH) GIST but in none of the 14 SDH preserved wild-type GIST or 21 TK mutant GIST samples analysed. Mean MGMT methylation was significantly higher (p 0.0449) and MGMT expression significantly lower (p<0.0001) in dSDH wtGIST compared with TK mutant or SDH preserved GIST. No correlation was identified between SDHx subunit gene mutations or SDHC epimutation status and mean MGMT methylation levels. CONCLUSION: MGMT promoter hypermethylation occurs exclusively in a subset of dSDH wtGIST. Data from this study support testing of tumour MGMT promoter methylation in patients with dSDH wtGIST to identify those patients who may benefit from most from TMZ therapy

A CMOS-compatible oscillation-based VO₂ Ising machine solver

Phase-encoded oscillating neural networks offer compelling advantages over metal-oxide-semiconductor-based technology for tackling complex optimization problems, with promising potential for ultralow power consumption and exceptionally rapid computational performance. In this work, we investigate the ability of these networks to solve optimization problems belonging to the nondeterministic polynomial time complexity class using nanoscale vanadium-dioxide-based oscillators integrated onto a Silicon platform. Specifically, we demonstrate how the dynamic behavior of coupled vanadium dioxide devices can effectively solve combinatorial optimization problems, including Graph Coloring, Max-cut, and Max-3SAT problems. The electrical mappings of these problems are derived from the equivalent Ising Hamiltonian formulation to design circuits with up to nine crossbar vanadium dioxide oscillators. Using sub-harmonic injection locking techniques, we binarize the solution space provided by the oscillators and demonstrate that graphs with high connection density (η &gt; 0.4) converge more easily towards the optimal solution due to the small spectral radius of the problem’s equivalent adjacency matrix. Our findings indicate that these systems achieve stability within 25 oscillation cycles and exhibit power efficiency and potential for scaling that surpasses available commercial options and other technologies under study. These results pave the way for accelerated parallel computing enabled by large-scale networks of interconnected oscillators.</p

Fast image deconvolution for enhancement of the resolution in the video rate terahertz imaging

International audienceA fast image deconvolution algorithm is used to demonstrate the resolution enhancement of video rate camera acquired Terahertz images. Our algorithm is based on variable splitting technique with the use of a family of sparsity inducing regularizers for the first time in an image deconvolution application, it is also suitable for practical applications in industry with computationally constrained conditions. The results of the proposed process provide substantial enhancement on the quality and resolution of THz images

Reducing model bias in a deep learning classifier using domain adversarial neural networks in the MINERvA experiment

We present a simulation-based study using deep convolutional neural networks (DCNNs) to identify neutrino interaction vertices in the MINERvA passive targets region, and illustrate the application of domain adversarial neural networks (DANNs) in this context. DANNs are designed to be trained in one domain (simulated data) but tested in a second domain (physics data) and utilize unlabeled data from the second domain so that during training only features which are unable to discriminate between the domains are promoted. MINERvA is a neutrino-nucleus scattering experiment using the NuMI beamline at Fermilab. $A$-dependent cross sections are an important part of the physics program, and these measurements require vertex finding in complicated events. To illustrate the impact of the DANN we used a modified set of simulation in place of physics data during the training of the DANN and then used the label of the modified simulation during the evaluation of the DANN. We find that deep learning based methods offer significant advantages over our prior track-based reconstruction for the task of vertex finding, and that DANNs are able to improve the performance of deep networks by leveraging available unlabeled data and by mitigating network performance degradation rooted in biases in the physics models used for training.Comment: 41 page

The role of [68 Ga]Ga-DOTATATE PET/CT in wild-type KIT/PDGFRA gastrointestinal stromal tumours (GIST).

BACKGROUND: [68 Ga]Ga-DOTATATE PET/CT is now recognised as the most sensitive functional imaging modality for the diagnosis of well-differentiated neuroendocrine tumours (NET) and can inform treatment with peptide receptor radionuclide therapy with [177Lu]Lu-DOTATATE. However, somatostatin receptor (SSTR) expression is not unique to NET, and therefore, [68 Ga]Ga-DOTATATE PET/CT may have oncological application in other tumours. Molecular profiling of gastrointestinal stromal tumours that lack activating somatic mutations in KIT or PDGFRA or so-called 'wild-type' GIST (wtGIST) has demonstrated that wtGIST and NET have overlapping molecular features and has encouraged exploration of shared therapeutic targets, due to a lack of effective therapies currently available for metastatic wtGIST. AIMS: To investigate (i) the diagnostic role of [68 Ga]Ga-DOTATATE PET/CT; and, (ii) to investigate the potential of this imaging modality to guide treatment with [177Lu]Lu-DOTATATE in patients with wtGIST. METHODS: [68 Ga]Ga-DOTATATE PET/CT was performed on 11 patients with confirmed or metastatic wtGIST and one patient with a history of wtGIST and a mediastinal mass suspicious for metastatic wtGIST, who was subsequently diagnosed with a metachronous mediastinal paraganglioma. Tumour expression of somatostatin receptor subtype 2 (SSTR2) using immunohistochemistry was performed on 54 tumour samples including samples from 8/12 (66.6%) patients who took part in the imaging study and 46 tumour samples from individuals not included in the imaging study. RESULTS: [68 Ga]Ga-DOTATATE PET/CT imaging was negative, demonstrating that liver metastases had lower uptake than background liver for nine cases (9/12 cases, 75%) and heterogeneous uptake of somatostatin tracer was noted for two cases (16.6%) of wtGIST. However, [68 Ga]Ga-DOTATATE PET/CT demonstrated intense tracer uptake in a synchronous paraganglioma in one case and a metachronous paraganglioma in another case with wtGIST. CONCLUSIONS: Our data suggest that SSTR2 is not a diagnostic or therapeutic target in wtGIST. [68 Ga]Ga-DOTATATE PET/CT may have specific diagnostic utility in differentiating wtGIST from other primary tumours such as paraganglioma in patients with sporadic and hereditary forms of wtGIST

Translating In Vivo Metabolomic Analysis of Succinate Dehydrogenase–Deficient Tumors Into Clinical Utility

Purpose Mutations in the mitochondrial enzyme succinate dehydrogenase (SDH) subunit genes are associated with a wide spectrum of tumors, including pheochromocytomas and paragangliomas, GI stromal tumors, renal cell carcinomas, and pituitary adenomas. SDH-related tumorigenesis is believed to be secondary to accumulation of the oncometabolite succinate. Our aim was to investigate the potential clinical applications of proton-1 magnetic resonance spectroscopy (1H-MRS) in a range of suspected SDH-related tumors. Patients and Methods Fifteen patients were recruited to this study. Respiratory-gated single-voxel 1H-MRS was performed at 3T to quantify the content of succinate at 2.4 ppm and choline at 3.22 ppm. Results A succinate peak was seen in six patients, all of whom had germ line SDHx mutations or loss of SDHB by immunohistochemistry. Succinate peaks were also detected in two patients with metastatic wild-type GI stromal tumors and no detectable germ line SDHx mutations but with somatic epimutations in SDHC. Three patients without tumor succinate peaks retained SDHB expression, consistent with SDH functionality. In six patients with borderline or absent peaks, technical difficulties such as motion artifact rendered 1H-MRS difficult to interpret. Sequential imaging in a patient with a metastatic abdominal paraganglioma demonstrated loss of the succinate peak after four cycles of [177Lu]DOTATATE, with a corresponding biochemical response in normetanephrine. Conclusion This study has demonstrated the translation into clinical practice of in vivo metabolomic analysis using 1H-MRS in patients with SDH-deficient tumors. Potential applications include noninvasive diagnosis and disease stratification, as well as monitoring of tumor response to targeted treatments. </jats:sec

SDHC epi-mutation testing in gastrointestinal stromal tumours and related tumours in clinical practice

Abstract: The enzyme succinate dehydrogenase (SDH) functions in the citric acid cycle and loss of function predisposes to the development of phaeochromocytoma/paraganglioma (PPGL), wild type gastrointestinal stromal tumour (wtGIST) and renal cell carcinoma. SDH-deficient tumours are most commonly associated with a germline SDH subunit gene (SDHA/B/C/D) mutation but can also be associated with epigenetic silencing of the SDHC gene. However, clinical diagnostic testing for an SDHC epimutation is not widely available. The objective of this study was to investigate the indications for and the optimum diagnostic pathways for the detection of SDHC epimutations in clinical practice. SDHC promoter methylation analysis of 32 paraffin embedded tumours (including 15 GIST and 17 PPGL) was performed using a pyrosequencing technique and correlated with SDHC gene expression. SDHC promoter methylation was identified in 6 (18.7%) tumours. All 6 SDHC epimutation cases presented with SDH deficient wtGIST and 3/6 cases had multiple primary tumours. No case of constitutional SDHC promoter hypermethylation was detected. Whole genome sequencing of germline DNA from three wtGIST cases with an SDHC epimutation, did not reveal any causative sequence anomalies. Herein, we recommend a diagnostic workflow for the detection of an SDHC epimutation in a service setting

Clinical and Molecular Features of Renal and Pheochromocytoma/Paraganglioma Tumor Association Syndrome (RAPTAS): Case Series and Literature Review.

CONTEXT: The co-occurrence of pheochromocytoma (PC) and renal tumors was linked to the inherited familial cancer syndrome von Hippel-Lindau (VHL) disease more than six decades ago. Subsequently, other shared genetic causes of predisposition to renal tumors and to PC, paraganglioma (PGL), or head and neck paraganglioma (HNPGL) have been described, but case series of non-VHL-related cases of renal tumor and pheochromocytoma/paraganglioma tumor association syndrome (RAPTAS) are rare. OBJECTIVE: To determine the clinical and molecular features of non-VHL RAPTAS by literature review and characterization of a case series. DESIGN: A review of the literature was performed and a retrospective study of referrals for investigation of genetic causes of RAPTAS. RESULTS: Literature review revealed evidence of an association, in addition to VHL disease, between germline mutations in SDHB, SDHC, SDHD, TMEM127, and MAX genes and RAPTAS [defined here as the co-occurrence of tumors from both classes (PC/PGL/HNPGL and renal tumors) in the same individual or in first-degree relatives]. In both the literature review and our case series of 22 probands with non-VHL RAPTAS, SDHB mutations were the most frequent cause of non-VHL RAPTAS. A genetic cause was identified in 36.3% (8/22) of kindreds. CONCLUSION: Renal tumors and PC/PGL/HNPGL tumors share common molecular features and their co-occurrence in an individual or family should prompt genetic investigations. We report a case of MAX-associated renal cell carcinoma and confirm the role of TMEM127 mutations with renal cell carcinoma predisposition