排序方式： 共有4条查询结果，搜索用时 15 毫秒
1
1.
Annamária Kiss Typhaine Moreau Vincent Mirabet Cerasela Iliana Calugaru Arezki Boudaoud Pradeep Das 《Plant methods》2017,13(1):114
Background
Developmental biology has made great strides in recent years towards the quantification of cellular properties during development. This requires tissues to be imaged and segmented to generate computerised versions that can be easily analysed. In this context, one of the principal technical challenges remains the faithful detection of cellular contours, principally due to variations in image intensity throughout the tissue. Watershed segmentation methods are especially vulnerable to these variations, generating multiple errors due notably to the incorrect detection of the outer surface of the tissue.Results
We use the level set method (LSM) to improve the accuracy of the watershed segmentation in different ways. First, we detect the outer surface of the tissue, reducing the impact of low and variable contrast at the surface during imaging. Second, we demonstrate a new edge function for a level set, based on second order derivatives of the image, to segment individual cells. Finally, we also show that the LSM can be used to segment nuclei within the tissue.Conclusion
The watershed segmentation of the outer cell layer is demonstrably improved when coupled with the LSM-based surface detection step. The tool can also be used to improve watershed segmentation at cell-scale, as well as to segment nuclei within a tissue. The improved segmentation increases the quality of analysis, and the surface detected by our algorithm may be used to calculate local curvature or adapted for other uses, such as mathematical simulations.2.
Bouvresse S Socolovshi C Berdjane Z Durand R Izri A Raoult D Chosidow O Brouqui P 《Comparative immunology, microbiology and infectious diseases》2011,34(6):475-477
The human body louse is the only known vector of Bartonella quintana. However, the presence of this bacterium has recently been detected in the head lice of homeless individuals and Nepalese slum children. Previous studies have reported the isolation of Acinetobacter baumannii from the body lice of homeless individuals. An epidemiological survey including 74 schools was conducted between 2008 and 2009 in Paris. After a first visual examination, the hair of children with suspected pediculosis was combed with a fine-tooth comb to collect live adult head lice. Molecular studies were performed on randomly selected DNA samples to detect B. quintana and A. baumannii by specific quantitative real-time PCR. Among a collection of 288 DNA samples, B. quintana was not detected, but A. baumannii was detected in 95 DNA samples (33%). Further study is needed to determine the significance of the finding of A. baumannii in head lice. 相似文献
3.
Physicochemical characterization of 82 Algerian honeys, collected between 2005 and 2010, from different botanical and geographical origins were analyzed. The studied parameters were： water content, pH, free acidity （FA）, electrical conductivity （EC）, ash content, hydroxymethylfurfuraldehyde （HMF）, proline content, specific rotatory power and color. Most of the measured parameters had showed values in the range of the international standards, with a particular richness in proline and ash content. Chemometrics-based approach reveals that the discriminated groups were Citrus, Ziziphus and forest even with over represented groups like Eucalyptus. Principle component analysis （PCA） enabled to extract three principal components explaining nearly 65% of total variance, PCj and PC2 were related to botanical origin whereas PC3 to honey age. Analysis of variance showed that the studied variables were almost different depending on botanical, geographical origin and season. The current study also shows the presence of diverse honey varieties in Algeria. The collected data will contribute to the creation of products with protected geographical or/and botanical origins. 相似文献
4.
Ilhem Selmi Davide Pacifico Arezki Lehad Egidio Stigliano Dalila Crucitti Francesco Carimi Naima Mahfoudhi 《Plant pathology》2020,69(6):1051-1059
Grapevine rupestris stem pitting-associated virus (GRSPaV) is one of the most widespread grapevine viruses and is transmitted mainly by grafting. GRSPaV presence was tested in 487 samples representative of the Tunisian grapevine germplasm (including autochthonous, table, wine, wild grape, and rootstock varieties) from different Tunisian regions. GRSPaV infection was detected in 51.3% of samples from different Tunisian regions, among which the table grapevine cultivars were the most commonly infected (68.7%). Genetic variability of GRSPaV isolates from wild and cultivated grapevines was assessed by sequencing the partial capsid protein (CP) gene of 19 Tunisian isolates and 1 Italian GRSPaV isolate from Sicily, and the partial RNA-dependent RNA polymerase (RdRp) gene of 13 Tunisian GRSPaV isolates. According to phylogenetic analysis of CP nucleotide sequences obtained in this study and sequences retrieved from GenBank, Tunisian isolates fell into four phylogenetic groups already described (I, II, III, and IV) and two new phylogenetic groups (VI and VIII). Phylogenetic analysis of the partial RdRp gene revealed that Tunisian isolates of GRSPaV are distributed into four phylogroups. This study highlights the importance of regular monitoring of GRSPaV infections in Tunisia, with special regard to those grapevine accessions employed in conservation and selection programmes. In particular, the presence of new GRSPaV genetic variants and infection of wild grapevines must be taken into account in order to choose a correct control strategy. 相似文献
1