174 research outputs found
Joint T1 and brain fiber diffeomorphic registration using the demons
International audienceImage registration is undoubtedly one of the most active areas of research in medical imaging. Within inter-individual comparison, registration should align images as well as cortical and external structures such as sulcal lines and fibers. While using image-based registration[1], neural fibers appear uniformly white giving no information to the registration. Tensor-based registration was recently proposed to improve white-matter alignment[2,3], however misregistration may also persist in regions where the tensor field appears uniform[4]. We propose an hybrid approach by extending the Diffeomorphic Demons(D)[5] registration to incorporate geometric constrains. Combining the deformation field induce by the image and the geometry, we define a mathematically sound framework to jointly register images and geometric descriptors such as fibers or sulcal lines
Validation of 3D Registration Methods based on Points and Frames
Published in Int. J. of Comp. Vision 25(3), 1997, p. 203-229International audienceno abstrac
Exploring Fully Biobased Adhesives: Sustainable Kraft Lignin and 5-HMF Adhesive for Particleboards
Most adhesives used in the wood-based panel (WBP) industry are petroleum-based and are associated with environmental impact and price fluctuations. Furthermore, most have potential adverse health impacts, such as formaldehyde emissions. This has led to interest from the WBP industry in developing adhesives with bio-based and/or non-hazardous components. This research focuses on the replacement of phenol-formaldehyde resins by Kraft lignin for phenol substitution and 5-hydroxymethylfurfural (5-HMF) for formaldehyde substitution. Resin development and optimization was carried out regarding varying parameters such as molar ratio, temperature or pH. The adhesive properties were analyzed using a rheometer, gel timer and a differential scanning calorimeter (DSC). The bonding performances were evaluated using an Automated Bonding Evaluation System (ABES). Particleboards were produced using a hot press, and their internal bond strength (IB) was evaluated according to SN EN 319. Hardening of the adhesive could be achieved at low temperatures by increasing or decreasing the pH. The most promising results were obtained at pH 13.7. The adhesive performances were improved by adding filler and extender (up to 28.6% based on dry resin) and several boards were produced reaching P1 requirements. A particleboard achieved a mean IB of 0.29 N/mm2, almost reaching almost P2 requirements. However, adhesive reactivity and strength must be improved for industrial use
Individual patient data meta-analysis of neoadjuvant chemotherapy followed by surgery versus upfront surgery for carcinoma of the oesophagus or the gastro- oesophageal junction
Introduction
Which neoadjuvant treatment for locally advanced thoracic oesophagus (TE) or gastro-oesophageal junction carcinoma is best remains an open question. Randomised controlled trials variously accrued patients with adenocarcinoma and squamous cell carcinoma, making strong conclusions hard to obtain. The primary objective of this individual participant data meta-analysis was to investigate the effect of neoadjuvant chemotherapy on overall survival (OS).
Patients and methods
Eligible trials should have closed to accrual before 2016 and compared neoadjuvant chemotherapy and surgery (CS) to surgery alone. All relevant published and unpublished trials were identified via searches of electronic databases, conference proceedings and clinical trial registers. The main end-point was OS. Investigators were contacted to obtain the individual patient data, which was recorded, harmonised and checked. A random-effects Cox model, stratified by trial, was used for meta-analysis and subgroup analyses were preplanned.
Results
16 trials were identified as eligible. Individual patient data were obtained from 12 trial and 2478 patients. CS was associated with an improved OS versus surgery, hazard ratio (HR) = 0.83 [0.72–0.96], p < 0.0001, translating to an absolute benefit of 5.7% at 5-years from 16.8% to 22.5%. Treatment effects did not vary substantially between adenocarcinoma (HR = 0.73 [0.62–0.87]) and squamous cell carcinoma (HR = 0.91 [0.76–1.08], interaction p = 0.26). A somewhat more pronounced effect was observed in gastro-oesophageal junction (HR = 0.68 [0.50–0.93]) versus TE (HR = 0.87 [0.75–1.00], interaction p = 0.07). CS was also associated with a greater disease-free survival (HR = 0.74 [0.64–0.85], p < 0.001).
Conclusions
Neoadjuvant chemotherapy conferred a better OS than surgery alone and should be considered in all anatomical location and histological subtypes
RNA and DNA Bacteriophages as Molecular Diagnosis Controls in Clinical Virology: A Comprehensive Study of More than 45,000 Routine PCR Tests
Real-time PCR techniques are now commonly used for the detection of viral genomes in various human specimens and require for validation both external and internal controls (ECs and ICs). In particular, ICs added to clinical samples are necessary to monitor the extraction, reverse transcription, and amplification steps in order to detect false-negative results resulting from PCR-inhibition or errors in the technical procedure. Here, we performed a large scale evaluation of the use of bacteriophages as ICs in routine molecular diagnosis. This allowed to propose simple standardized procedures (i) to design specific ECs for both DNA and RNA viruses and (ii) to use T4 (DNA) or MS2 (RNA) phages as ICs in routine diagnosis. Various technical formats for using phages as ICs were optimised and validated. Subsequently, T4 and MS2 ICs were evaluated in routine real-time PCR or RT-PCR virological diagnostic tests, using a series of 8,950 clinical samples (representing 36 distinct specimen types) sent to our laboratory for the detection of a variety of DNA and RNA viruses. The frequency of inefficient detection of ICs was analyzed according to the nature of the sample. Inhibitors of enzymatic reactions were detected at high frequency in specific sample types such as heparinized blood and bone marrow (>70%), broncho-alveolar liquid (41%) and stools (36%). The use of T4 and MS2 phages as ICs proved to be cost-effective, flexible and adaptable to various technical procedures of real-time PCR detection in virology. It represents a valuable strategy for enhancing the quality of routine molecular diagnosis in laboratories that use in-house designed diagnostic systems, which can conveniently be associated to the use of specific synthetic ECs. The high rate of inhibitors observed in a variety of specimen types should stimulate the elaboration of improved technical protocols for the extraction and amplification of nucleic acids
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