Identification of COVID-19 samples from chest X-Ray images using deep learning:a comparison of transfer learning approaches

Abstract Background: The novel coronavirus disease 2019 (COVID-19) constitutes a public health emergency globally. The number of infected people and deaths are proliferating every day, which is putting tremendous pressure on our social and healthcare system. Rapid detection of COVID-19 cases is a significant step to fight against this virus as well as release pressure off the healthcare system. Objective: One of the critical factors behind the rapid spread of COVID-19 pandemic is a lengthy clinical testing time. The imaging tool, such as Chest X-ray (CXR), can speed up the identification process. Therefore, our objective is to develop an automated CAD system for the detection of COVID-19 samples from healthy and pneumonia cases using CXR images. Methods: Due to the scarcity of the COVID-19 benchmark dataset, we have employed deep transfer learning techniques, where we examined 15 different pre-trained CNN models to find the most suitable one for this task. Results: A total of 860 images (260 COVID-19 cases, 300 healthy and 300 pneumonia cases) have been employed to investigate the performance of the proposed algorithm, where 70% images of each class are accepted for training, 15% is used for validation, and rest is for testing. It is observed that the VGG19 obtains the highest classification accuracy of 89.3% with an average precision, recall, and F1 score of 0.90, 0.89, 0.90, respectively. Conclusion: This study demonstrates the effectiveness of deep transfer learning techniques for the identification of COVID-19 cases using CXR images

Plastome phylogenomics of sugarcane and relatives confirms the segregation of the genus Tripidium (Poaceae: Andropogoneae)

Sugarcane (Saccharum officinarum) is one of the most important crops inthe world and a major source of sugar for human consumption. Despite this immense value, the circumscription of the genus Saccharum is complex, contentious, and largely unresolved. Saccharum is accepted in a broad sense by some authors or split into various genera such as Erianthus and Tripidium. A plastome phylogenomic analysis of sugarcane and relatives was performed in order to investigate generic delimitation, with emphasis on Tripidium (= Erianthus sect. Ripidium). Our plastome phylogenomics clearly demonstrates that Saccharum s.l. is polyphyletic and Tripidium (distributed in Old World) belongs to a distinct lineage from Saccharum s.s. (Old World) and Erianthus s.s. (= Erianthus sect. Erianthus, New World). Therefore, the present analysis confirms the recognition of Tripidium as a distinct genus from Saccharum and Erianthus, which is also supported by morphology and nuclear markers. The circumscription of Erianthus s.s. remains unclear since our plastome phylogenomics is consistent with either considering it as a distinct genus or including it in Saccharum. Better understanding of the evolutionary relationships of sugarcane and relatives may be useful for the selection of potential taxa for interspecific and intergeneric crosses in the genetic improvement of sugarcane. A taxonomic treatment of the six species of Tripidium is also presented, including descriptions, illustrations, data on geographical distribution, and three new nomenclatural combinations.Fil: Welker, Cassiano A. D.. Universidade Federal de Uberlândia; BrasilFil: McKain, Michael R.. University of Alabama at Birmingahm; Estados UnidosFil: Vorontsova, Maria S.. Royal Botanic Gardens; Reino UnidoFil: Peichoto, Myriam Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Kellogg, Elizabeth Anne. Donald Danforth Plant Science Center; Estados Unido

Vinblastine 20′ Amides: Synthetic Analogues That Maintain or Improve Potency and Simultaneously Overcome Pgp-Derived Efflux and Resistance

A series of 180 vinblastine 20′ amides were prepared in three steps from commercially available starting materials, systematically exploring a typically inaccessible site in the molecule enlisting a powerful functionalization strategy. Clear structure–activity relationships and a structural model were developed in the studies which provided many such 20′ amides that exhibit substantial and some even remarkable enhancements in potency, many that exhibit further improvements in activity against a Pgp overexpressing resistant cancer cell line, and an important subset of the vinblastine analogues that display little or no differential in activity against a matched pair of vinblastine sensitive and resistant (Pgp overexpressing) cell lines. The improvements in potency directly correlated with target tubulin binding affinity, and the reduction in differential functional activity against the sensitive and Pgp overexpressing resistant cell lines was found to correlate directly with an impact on Pgp-derived efflux

Vinblastine 20′ Amides: Synthetic Analogues That Maintain or Improve Potency and Simultaneously Overcome Pgp-Derived Efflux and Resistance

A series of 180 vinblastine 20′ amides were prepared in three steps from commercially available starting materials, systematically exploring a typically inaccessible site in the molecule enlisting a powerful functionalization strategy. Clear structure–activity relationships and a structural model were developed in the studies which provided many such 20′ amides that exhibit substantial and some even remarkable enhancements in potency, many that exhibit further improvements in activity against a Pgp overexpressing resistant cancer cell line, and an important subset of the vinblastine analogues that display little or no differential in activity against a matched pair of vinblastine sensitive and resistant (Pgp overexpressing) cell lines. The improvements in potency directly correlated with target tubulin binding affinity, and the reduction in differential functional activity against the sensitive and Pgp overexpressing resistant cell lines was found to correlate directly with an impact on Pgp-derived efflux