Mobile-PolypNet : Light-weight Colon Polyp Segmentation Network for Low Resources Settings

Colon polyps, small clump of cells on the lining of the colon can lead to Colorectal cancer (CRC), one of the leading types of cancer globally. Hence, early detection of these polyps is crucial in the prevention of CRC. This paper proposes a lightweight deep learning model for colorectal polyp segmentation that achieved state-of-the-art accuracy while significantly reducing the model size and complexity. The proposed deep learning autoencoder model employs a set of state-of-the-art architectural blocks and optimization objective functions to achieve the desired efficiency. The model is trained and tested on five publicly available colorectal polyp segmentation datasets (CVC-ClinicDB, CVC-ColonDB, EndoScene, Kvasir, and ETIS). We also performed ablation testing on the model to test various aspects of the autoencoder architecture. We performed the model evaluation using most of the common image segmentation metrics. The backbone model achieved a dice score of 0.935 on the Kvasir dataset and 0.945 on the CVC-ClinicDB dataset improving the accuracy by 4.12% and 5.12% respectively over the current state-of-the-art network, while using 88 times fewer parameters, 40 times less storage space, and being computationally 17 times more efficient. Our ablation study showed that the addition of ConvSkip in the autoencoder slightly improves the model’s performance but it was not significant (p-value=0.815).

CO J=2-1 observations toward the OH 1720 MHz maser in Kes 69

We present CO J=2-1 observations made with the 12 Meter Telescope of NRAO using the On-The-Fly technique, towards the OH 1720 MHz maser detected in direction to the supernova remnant (SNR) Kes 69. OH 1720 MHz masers associated to SNRs are strong evidence of shocked molecular gas, and are proposed to be tracers of SNRs kinematical distances. In our images, the most conspicuous feature positionally coincident with the maser is a cloud at ∼ +41 km s−1. The difference between the velocity of the OH 1720 MHz maser and this cloud is ∼ 30 km s−1. At the systemic velocity of the OH 1720 MHz maser, we detected a weak, small clump with the maser lying at its edge, in agreement with previous findings in other SNRs. We suggest that this small clump has been shocked by the expanding SNR, and the ∼ +41 km s−1 component probably corresponds to gas accelerated by the shock front. We do not discard, however, that the ∼ +41 km s−1 component be just a quiescent, foreground cloud unrelated to Kes 69.

Microscale Diversity of the GenusNitrobacter in Soil on the Basis of Analysis of Genes Encoding rRNA

ABSTRACT We looked at the diversity of NO2 −oxidizers at field scale by examining isolates at clump scale and in microsamples of soil (diameter, 50 μm). The genetic distances (as determined by amplified ribosomal DNA restriction analysis performed with Nitrobacter-specific primers) in a small clump of soil were as large as those between reference strains from large geographical areas. Diversity in individual microsamples was shown by serotyping.

Electron Microscopic Studies of Fibrinogen Degradation Products

Many of the details regarding the organization and tertiary structure of fibrinogen are still controversial. Regarding the disulfide bonds which link the two halves of fibrinogen, one group considers that such bonds link the amino terminal parts together and that plasmic degradation leads to the formation of two Fragment D derivatives. The alternate model considers the two halves of fibrinogen to be linked by disulfide bonds in two regions and that plasmin liberates a single dimeric Fragment D molecule. This question was approached by a study of the electron microscopic appearance of fibrinogen and its plasmic derivatives. Fragment X obtained from Stage 1 digests and fibrinogen were both globular, while Fragment X of Stage 2 digests appeared as a nodular filament. The Stage 1 and Stage 2 Fragment X preparations had approximately the same molecular weight, but could be differentiated by subtle differences in polypeptide chain structure. Fragments Y and D were also filamentous, although shorter than Fragment X (Stage 2), and Fragment E appeared as a small clump of nodules. These results agree with the concept that fibrinogen consists of a strand of nodules connected by thin filaments, folded into a compact, spherical shape. The molecule opens up when stabilizing bonds are disrupted or liberated by plasmin. The data are compatible with a fibrinogen molecule in which the two halves are linked by a single locus of disulfide bonds at the amino terminus and with the asymmetric hypothesis of plasmic degradation to Fragments X, Y, D and E.

An immuno-fluorescent study of lens regeneration in larval Xenopus laevis

It is well known that several species of amphibia, especially those of the genus Triturus, can regenerate a lens after removal of the original lens from the eye. In most of these species the regenerate develops from the iris (Reyer, 1954), but in larval Xenopus laevis (Overton &Freeman, 1960; Freeman & Overton, 1961, 1962; Freeman, 1963; Campbell, 1963) and possibly in early embryonic stages of Hynobius unnangso (Ikeda, 1936, 1939) the regenerating lens can be formed from corneal tissue. The morphological changes associated with regeneration of the lens from the cornea in X. laevis have been fully described by Freeman (1963), who has shown that the regenerate develops from the inner cell layer of the outer, or ectodermal, cornea, appearing initially as a small clump of cells in the midpupillary region. This aggregate organizes into a vesicle, from the posterior wall of which the primary lens fibres are formed.