| 1. |
- Björkholm, P., et al.
(författare)
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Navigation in vehicle crash test using MEMS-based IMU
- 2010
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Ingår i: IEEE PLANS, Position Location and Navigation Symposium. - 9781424450367 ; , s. 27-31
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Results from our experiments on inertial navigation in crash testing of vehicles are presented. A custom designed inertial measurement unit (IMU) has been developed, and several tests in dummy calibration rigs including full-scale Euro NCAP collisions have been performed at our partners' crash test laboratories. For reference, the IMU data is compared to camera data and traditional single-axis inertial sensors. ©2010 IEEE.
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| 2. |
- Kumaresan, A., et al.
(författare)
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Quantification of kinetic changes in protein tyrosine phosphorylation and cytosolic Ca2+ concentration in boar spermatozoa during cryopreservation
- 2012
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Ingår i: Reproduction, Fertility and Development. - 1031-3613 .- 1448-5990. ; 24:4, s. 531-542
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Tidskriftsartikel (refereegranskat)abstract
- Protein tyrosine phosphorylation in sperm is associated with capacitation in several mammalian species. Although tyrosine phosphorylated proteins have been demonstrated in cryopreserved sperm, indicating capacitation-like changes during cryopreservation, these changes have not yet been quantified objectively. We monitored tyrosine phosphorylation, intracellular calcium and sperm kinematics throughout the cryopreservation process, and studied the relationships among them in boar spermatozoa. Sperm kinetics changed significantly during cryopreservation: curvilinear velocity, average path velocity and straight line velocity all decreased significantly (P < 0.05). While the percentage of sperm with high intracellular calcium declined (P < 0.05), global phosphorylation increased significantly (P < 0.01). Specifically, cooling to 5 degrees C induced phosphorylation in the spermatozoa. After cooling, a 32-kDa protein not observed in fresh semen appeared and was consistently present throughout the cryopreservation process. While the level of expression of this phosphoprotein decreased after addition of the second extender, frozen-thawed spermatozoa showed an increased expression. The proportion of sperm cells with phosphorylation in the acrosomal area also increased significantly (P < 0.05) during cryopreservation, indicating that phosphorylation might be associated with capacitation-like changes. These results provide the first quantitative evidence of dynamic changes in the subpopulation of boar spermatozoa undergoing tyrosine phosphorylation during cryopreservation.
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| 3. |
- Siqueira, A P, et al.
(författare)
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Quality of boar spermatozoa from the sperm-peak portion of the ejaculate after simplified freezing in MiniFlatpacks compared to the remaining spermatozoa of the sperm-rich fraction
- 2011
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Ingår i: THERIOGENOLOGY. - : Elsevier Science B.V., Amsterdam.. - 0093-691X .- 1879-3231. ; 75:7, s. 1175-1184
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Tidskriftsartikel (refereegranskat)abstract
- Boar sperm viability post-thaw differs depending on the ejaculate fraction used, with spermatozoa present in the first 10 mL of the sperm-rich fraction (SRF) (portion 1, P1, sperm-peak portion) displaying the best cryosurvival in vitro compared with that of spermatozoa from the rest of the ejaculate (portion 2 of the SRF plus the post-spermatic fraction), even when using simplified freezing routines. This viability apparently relates to the specific profile of seminal plasma in P1 (i.e., glycoprotein and bicarbonate concentrations, and pH). However, spermatozoa from PI have not been compared with spermatozoa from the rest of the SRF (SRF P1, usually 30-40 mL of the SRF), which is routinely used for freezing. We compared P1 with SRF P I in terms of sperm kinematics (using the QualiSperm (TM) system), while membrane integrity (SYBR-14/PI), acrosome integrity (FITC PNA/PI), and sperm membrane stability (Annexin-V) were explored using flow cytomety. As well, total protein concentration and the proteomics of the seminal plasma (SP) of both portions of the SRF were studied using two-dimensional electrophoresis (2DE), mass fingerprinting (MALDI-TOF), and collision-induced dissociation tandem mass spectrometry (CID-MS/MS) on selected peptides. The SRF portions were collected weekly from four mature boars (4-5 replicates per boar, sperm concentration: P1, 1.86 +/- 0.20; SRF P1, 1.25 +/- 0.14 x 10(9) spz/mL) and processed using a quick freezing method in MiniFlatPacks. Post-thaw sperm motility reached 50%, without differences between SRF portions, but with clear inter-boar variation. Neither plasma membrane nor acrosome integrity differed (ns) between fractions. These results indicate that there are no differences in cryosurvival after quick freezing of boar spermatozoa derived from either of the two SRF portions. While P1 and SRF-P1 clearly differed in relative total protein contents, as expected, they displayed very similar protein profiles as assessed using 2DE and mass spectrometry (tryptic peptide mass fingerprint analysis and CID-MS/MS), indicating a similar emission of epididymal protein content.
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