A Modulated Closed Form solution for Quantitative Susceptibility Mapping - A thorough evaluation and comparison to iterative methods based on edge prior knowledge.

The aim of this study is to perform a thorough comparison of quantitative susceptibility mapping (QSM) techniques and their dependence on the assumptions made. The compared methodologies were: two iterative single orientation methodologies minimizing the l2, l1TV norm of the prior knowledge of the edges of the object, one over-determined multiple orientation method (COSMOS) and anewly proposed modulated closed-form solution (MCF). The performance of these methods was compared using a numerical phantom and in-vivo high resolution (0.65mm isotropic) brain data acquired at 7T using a new coil combination method. For all QSM methods, the relevant regularization and prior-knowledge parameters were systematically changed in order to evaluate the optimal reconstruction in the presence and absence of a ground truth. Additionally, the QSM contrast was compared to conventional gradient recalled echo (GRE) magnitude and R2* maps obtained from the same dataset. The QSM reconstruction results of the single orientation methods show comparable performance. The MCF method has the highest correlation (corrMCF=0.95, r(2)MCF =0.97) with the state of the art method (COSMOS) with additional advantage of extreme fast computation time. The l-curve method gave the visually most satisfactory balance between reduction of streaking artifacts and over-regularization with the latter being overemphasized when the using the COSMOS susceptibility maps as ground-truth. R2* and susceptibility maps, when calculated from the same datasets, although based on distinct features of the data, have a comparable ability to distinguish deep gray matter structures

An illustrated comparison of processing methods for MR phase imaging and QSM: combining array coil signals and phase unwrapping

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Effect of Subtilisin-like Proteinase of Bacillus pumilus 3–19 on Pseudomonas aeruginosa Biofilms

© 2019, Springer Science+Business Media, LLC, part of Springer Nature. Pseudomonas aeruginosa is a common device-associated pathogen and also a model object in biofilm research. In this study biofilm growth dynamics of Pseudomonas aeruginosa RSC-2 strain on different culture media was described. It was shown that Mueller-Hinton broth is more suitable for biofilm growth than Lysogeny broth. In vitro biofilm surface was investigated using scanning electron microscopy. Staining with Congo red dye demonstrated that the observed strain can produce amyloid-like fibers that play important role in biofilms and are proposed to be a target for proteinase treatment. The effect of subtilisin-like proteinase of Bacillus pumilus 3–19, trypsin, and proteinase K on biofilm was studied. All of these proteinases can destroy biofilms depending on the time of incubation and enzyme activity. After 4 h of incubation, 18–47% of biofilms were destroyed, which can be linked to the resistance of amyloid proteins to proteolytic degradation. However, an increase in the incubation time (to 24 h) led to complete destruction of biofilm

Effect of Subtilisin-like Proteinase of Bacillus pumilus 3–19 on Pseudomonas aeruginosa Biofilms

© 2019, Springer Science+Business Media, LLC, part of Springer Nature. Pseudomonas aeruginosa is a common device-associated pathogen and also a model object in biofilm research. In this study biofilm growth dynamics of Pseudomonas aeruginosa RSC-2 strain on different culture media was described. It was shown that Mueller-Hinton broth is more suitable for biofilm growth than Lysogeny broth. In vitro biofilm surface was investigated using scanning electron microscopy. Staining with Congo red dye demonstrated that the observed strain can produce amyloid-like fibers that play important role in biofilms and are proposed to be a target for proteinase treatment. The effect of subtilisin-like proteinase of Bacillus pumilus 3–19, trypsin, and proteinase K on biofilm was studied. All of these proteinases can destroy biofilms depending on the time of incubation and enzyme activity. After 4 h of incubation, 18–47% of biofilms were destroyed, which can be linked to the resistance of amyloid proteins to proteolytic degradation. However, an increase in the incubation time (to 24 h) led to complete destruction of biofilm