Time filter

Source Type

Lund, Sweden

Andersson R.,Lund University | Cinthio M.,Lund University | Evertsson M.,Lund University | Toftevall H.,Geccodots AB | And 5 more authors.
2015 IEEE International Ultrasonics Symposium, IUS 2015 | Year: 2015

Magnetomotive ultrasound imaging is an emerging technique where superparamagnetic iron oxide nanoparticles can be used as an ultrasound contrast agent. A time-varying external magnetic field acts to move tissue embedded particles, and ultrasound is used to detect the resulting tissue movement. In experimental phantom studies we have observed a phase lag dispersion in the magnetomotive response in respect to applied time-varying magnetic field (B-field). We hypothesize that this dispersion is triggered by the strength of the applied B-field in combination with concentration of embedded nanoparticles in the region. The cohort response of the nanoparticles aligns as the magnetic field gets more energetic. Moreover, the tightening of the phase response indicate an asymptotic tapering towards a phase limit. © 2015 IEEE. Source

Shadnezhad A.,Lund University | Naegeli A.,Lund University | Sjogren J.,Lund University | Sjogren J.,Genovis AB | And 6 more authors.
Future Microbiology | Year: 2016

Aim: The aim of this study was to identify and characterize EndoS-like enzymes in Streptococcus dysgalactiae subspecies dysgalactiae (SDSD). Materials & methods: PCR, DNA sequencing, recombinant protein expression, lectin blot, ultra high performance liquid chromatography analysis and a chitinase assay were used to identify ndoS-like genes and characterize EndoSd. Results: EndoSd were found in four SDSD strains. EndoSd hydrolyzes the chitobiose core of the glycan on IgG. The amino acid sequence of EndoSd is 70% identical to EndoS in S. pyogenes, but it has a unique C-terminal sequence. EndoSd secretion is influenced by the carbohydrate composition of the growth medium. Conclusion: Our findings indicate that IgG glycan hydrolyzing activity is present in SDSD, and that the activity can be attributed to the here identified enzyme EndoSd. © 2016 Azadeh Shadnezhad. Source

The invention provides an endoglycosidase, referred to as EndoS49 and having the amino acid sequence of SEQ ID NO: 1. EndoS49 was isolated from

Evertsson M.,Lund University | Cinthio M.,Lund University | Fredriksson S.,Genovis AB | Olsson F.,Genovis AB | And 2 more authors.
IEEE International Ultrasonics Symposium, IUS | Year: 2011

In magnetomotive ultrasound (MMUS) imaging superparamagnetic iron oxide nanoparticles (NP) are used as contrast agents and a time-varying external magnetic field acts to move the particles and thereby the nanoparticle-laden tissue. Recently we proposed a frequency and phase sensitive algorithm to reduce motion artifacts. However, the method is not quantitative as the particle movement induced is dependent not only on the field strength, but also on the field gradient, plus material parameters. Here we assess the measured nanoparticle movement across the image plane in comparison with simulations of the magnetic force, to evaluate the potential for image normalization of magnetic field effects. We found that the movement decreased with distance to the iron core tip, from which the magnetic field was extending, and approaches zero at the transducer face. This finding did not coincide with the simulation and may make it difficult to enable quantification. The coefficient of variation between measurements on the homogeneous phantom was typically in the order of 15% for all frequencies, indicating the expected accuracy for quantitative measurements. © 2011 IEEE. Source

Evertsson M.,Lund University | Cinthio M.,Lund University | Fredriksson S.,Genovis AB | Olsson F.,Genovis AB | And 2 more authors.
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control | Year: 2013

It has recently been demonstrated that superparamagnetic iron oxide nanoparticles can be used as magnetomotive ultrasound contrast agents. A time-varying external magnetic field acts to move the particles and, thus, the nanoparticle-laden tissue. However, the difficulty of distinguishing this magnetomotive motion from undesired movement induced in regions without nanoparticles or other motion artifacts has not been well reported. Using a high-frequency linear-array system, we found that displacements outside nanoparticle-laden regions can be similar in magnitude to those in regions containing nanoparticles. We also found that the displacement outside the nanoparticle regions had a phase shift of approximately π radians relative to that in the nanoparticle regions. To suppress signals arising from undesirable movements, we developed an algorithm based on quadrature detection and phase gating at the precise frequency of nanoparticle displacement. Thus, clutter at other frequencies can be filtered out, and the processed signal can be color-coded and superimposed on the B-mode image. The median signal-to-clutter ratio improvement using the proposed algorithm was 36 dB compared with simply summing the movement energy at all frequencies. This clutter rejection is a crucial step to move magnetomotive ultrasound imaging of nanoparticles toward in vivo investigations. © 1986-2012 IEEE. Source

Discover hidden collaborations