| 1. |
- Ahola, Virpi, et al.
(författare)
-
The Glanville fritillary genome retains an ancient karyotype and reveals selective chromosomal fusions in Lepidoptera
- 2014
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 5, s. 4737-
-
Tidskriftsartikel (refereegranskat)abstract
- Previous studies have reported that chromosome synteny in Lepidoptera has been well conserved, yet the number of haploid chromosomes varies widely from 5 to 223. Here we report the genome (393 Mb) of the Glanville fritillary butterfly (Melitaea cinxia; Nymphalidae), a widely recognized model species in metapopulation biology and eco-evolutionary research, which has the putative ancestral karyotype of n = 31. Using a phylogenetic analyses of Nymphalidae and of other Lepidoptera, combined with orthologue-level comparisons of chromosomes, we conclude that the ancestral lepidopteran karyotype has been n = 31 for at least 140 My. We show that fusion chromosomes have retained the ancestral chromosome segments and very few rearrangements have occurred across the fusion sites. The same, shortest ancestral chromosomes have independently participated in fusion events in species with smaller karyotypes. The short chromosomes have higher rearrangement rate than long ones. These characteristics highlight distinctive features of the evolutionary dynamics of butterflies and moths.
|
|
| 2. |
|
|
| 3. |
- Brihuega, Alberto, et al.
(författare)
-
On the Power and Beam Dependency of Load Modulation in mmWave Active Antenna Arrays
- 2020
-
Ingår i: 2020 50TH EUROPEAN MICROWAVE CONFERENCE (EUMC). - 2325-0305.
-
Konferensbidrag (refereegranskat)abstract
- Linearization of active antenna arrays is gaining increasing interest due to their wide applicability in 5G New Radio (NR) networks. As direct access to the output ports of the power amplifiers (PAs) in highly integrated millimeter-wave (mmW) active arrays is difficult, different over-the-air (OTA) digital predistortion (DPD) solutions have been recently proposed. Large majority of such solutions build on the assumption that the nonlinear behaviors of the parallel PA units are independent of the beam direction. However, in this paper, we show through comprehensive OTA measurements on a commercial 64-element active array operating at 28 GHz, that the nonlinear distortion characteristics and the involved load modulation phenomenon largely depend on the beam direction as well as on the considered transmit power, and also that the beam-dependence increases with increasing transmit power. The findings of the measurements are also connected to the state-of-the-art PA models, paving the way towards the development of more efficient DPD solutions and the associated parameter learning methods for mmW active antenna array transmitters.
|
|
| 4. |
- Brihuega, Alberto, et al.
(författare)
-
Piecewise Digital Predistortion for mmWave Active Antenna Arrays: Algorithms and Measurements
- 2020
-
Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 68:9, s. 4000-4017
-
Tidskriftsartikel (refereegranskat)abstract
- In this article, we describe a novel framework for digital predistortion (DPD)-based linearization of strongly nonlinear millimeter-wave active antenna arrays. Specifically, we formulate a piecewise (PW) closed-loop (CL) DPD solution and low-complexity gradient-adaptive parameter learning algorithms, together with a region partitioning method, which can efficiently handle deep compression of the PA units. The impact of beamsteering on the DPD performance is studied, showing strong beam-dependence, thus necessitating frequent updating of the DPD. In order to facilitate fast adaptation, an inexpensive, noniterative, pruning algorithm is introduced, which allows us to significantly reduce the number of model coefficients. The proposed methods are validated with extensive over-the-air RF measurements on a 64-element active antenna array transmitter operating at 28-GHz carrier frequency and transmitting a 400-MHz 5G new radio (NR) standard-compliant orthogonal frequency-division multiplexing waveform. The obtained results demonstrate the excellent linearization capabilities of the proposed solution, conforming to the new 5G NR requirements for frequency range 2 (FR2) in terms of both in-band waveform quality and out-of-band emissions. The proposed PW-CL DPD is shown to outperform the state-of-the-art PW DPD based on the indirect learning architecture, as well as the classical single-polynomial-based DPD solutions in terms of linearization performance and computational complexity by a clear margin.
|
|
| 5. |
- Finnilä, Mikko A J, et al.
(författare)
-
Mineral Crystal Thickness in Calcified Cartilage and Subchondral Bone in Healthy and Osteoarthritic Human Knees
- 2022
-
Ingår i: Journal of Bone and Mineral Research. - : Wiley. - 1523-4681 .- 0884-0431. ; 37:9, s. 1700-1710
-
Tidskriftsartikel (refereegranskat)abstract
- Osteoarthritis (OA) is the most common joint disease, where articular cartilage degradation is often accompanied with sclerosis of the subchondral bone. However, the association between OA and tissue mineralization at the nanostructural level is currently not understood. In particular, it is technically challenging to study calcified cartilage, where relevant but poorly understood pathological processes such as tidemark multiplication and advancement occur. Here, we used state-of-the-art microfocus small-angle X-ray scattering with a 5-μm spatial resolution to determine the size and organization of the mineral crystals at the nanostructural level in human subchondral bone and calcified cartilage. Specimens with a wide spectrum of OA severities were acquired from both medial and lateral compartments of medial compartment knee OA patients (n = 15) and cadaver knees (n = 10). Opposing the common notion, we found that calcified cartilage has thicker and more mutually aligned mineral crystals than adjoining bone. In addition, we, for the first time, identified a well-defined layer of calcified cartilage associated with pathological tidemark multiplication, containing 0.32 nm thicker crystals compared to the rest of calcified cartilage. Finally, we found 0.2 nm thicker mineral crystals in both tissues of the lateral compartment in OA compared with healthy knees, indicating a loading-related disease process because the lateral compartment is typically less loaded in medial compartment knee OA. In summary, we report novel changes in mineral crystal thickness during OA. Our data suggest that unloading in the knee might be involved with the growth of mineral crystals, which is especially evident in the calcified cartilage.
|
|
| 6. |
- Hautala, Lauri, et al.
(författare)
-
Probing RbBr solvation in freestanding sub-2 nm water clusters
- 2017
-
Ingår i: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 19:36, s. 25158-25167
-
Tidskriftsartikel (refereegranskat)abstract
- Concentration dependent solvation of RbBr in freestanding sub-2 nm water clusters was studied using core level photoelectron spectroscopy with synchrotron radiation. Spectral features recorded from dilute to saturated clusters indicate that either solvent shared or contact ion pairs are present in increasing amount when the concentration exceeds 2 mol kg-1. For comparison, spectra from anhydrous RbBr clusters are also presented.
|
|
| 7. |
- Huttu, Mari, et al.
(författare)
-
Effects of medium and temperature on cellular responses in the superficial zone of hypo-osmotically challenged articular cartilage.
- 2012
-
Ingår i: Journal of Functional Biomaterials. - Basel, Switzerland : MDPI AG. - 2079-4983. ; 3:3, s. 544-555
-
Tidskriftsartikel (refereegranskat)abstract
- Osmotic loading of articular cartilage has been used to study cell-tissue interactions and mechanisms in chondrocyte volume regulation in situ. Since cell volume changes are likely to affect cell's mechanotransduction, it is important to understand how environmental factors, such as composition of the immersion medium and temperature affect cell volume changes in situ in osmotically challenged articular cartilage. In this study, chondrocytes were imaged in situ with a confocal laser scanning microscope (CLSM) through cartilage surface before and 3 min and 120 min after a hypo-osmotic challenge. Samples were measured either in phosphate buffered saline (PBS, without glucose and Ca(2+)) or in Dulbecco's modified Eagle's medium (DMEM, with glucose and Ca(2+)), and at 21 °C or at 37 °C. In all groups, cell volumes increased shortly after the hypotonic challenge and then recovered back to the original volumes. At both observation time points, cell volume changes as a result of the osmotic challenge were similar in PBS and DMEM in both temperatures. Our results indicate that the initial chondrocyte swelling and volume recovery as a result of the hypo-osmotic challenge of cartilage are not dependent on commonly used immersion media or temperature.
|
|
| 8. |
- Linna, Petri, et al.
(författare)
-
Assessment of social media skills among vocational teachers in Finland
- 2015
-
Ingår i: EDULEARN 15. - Valencia, Spain : The International Academy of Technology, Education and Development. - 9788460682431 ; , s. 4574-4581
-
Konferensbidrag (refereegranskat)abstract
- Information technology penetration in the automotive industry has forced education in upper secondary vocational teaching to radically change. In car mechanic training this has an influence on traditional teaching methods as well as upon the substance of the education. At the same time education is generally changing to use social media (SOME) tools in various novel pedagogical settings. SOME may be seen as one solution to the challenges to the automotive sector. However, teachers need to be motivated to enter into a new era of education. In this case study we explore the upper secondary vocational teachers' ability to utilize SOME in teaching. We planned, tested and verified an assessment tool for evaluating SOME skills among vocational teachers. We also planned and provided training for vocational teachers in the use of SOME tools. Our findings were that the ability to utilize SOME tools among vocational teachers was not good and teachers were surprisingly conservative towards new educational technology. We discovered that utilizing an assessment survey questionnaire before and feedback questionnaire afterwards, greatly benefited a training course by plugging existing knowledge gaps and planning the training accordingly.
|
|
| 9. |
- Saari, Mika, et al.
(författare)
-
Explorative Study Of Teaching Programming To Vocational Teachers In Finland
- 2015
-
Ingår i: Edulearn 15. - Valencia, Spain : The International Academy of Technology, Education and Development. - 9788460682431 ; , s. 2860-2869
-
Konferensbidrag (refereegranskat)abstract
- In this study we explore the possibility of organizing and structuring an information technology training day for upper secondary vocational teacher training in automotive and transport engineering. The objective is to show the development process of the three training sessions in response to survey data completed by teachers. Information technology has widely penetrated into the car industry during the last few decades but some teachers have difficulty in adapting and teaching new technologies to their students. This paper presents one approach to break the ice between 'old school' teachers and information technology, through the use of an 8-hour training day consisting of programming, electronic technology and data bus technology.The aim of this study is to discover how to structure training of new technology for experienced vocational teachers. In this paper we describe how we developed, organized and assessed information technology training for vocational teachers within the case study. The training day was organized in three locations in Finland: Pori, Jyvaskyla and Vantaa. After the first surveys were completed by the vocational teachers, the arrangement of the next training day was adjusted in response to the outcome of the initial surveys. After the first lecture session, the training feedback indicated that there should be more 'learning-by-doing' type of action. The next sessions included Arduino board [1], electronic components and a laptop software development environment.In this study we found that the attitudes of the training attendees were different in three locations around Finland. This is an interesting finding. When comparing the results obtained from Jyvaskyla and Vantaa the outcomes were slightly more negative in Jyvaskyla than in Vantaa. However the training was identical in both cases. The results also showed a difference in attitude between teachers of different age groups.One of the biggest problems in this type of training was the limitation of time. Most of the teachers were familiar with the automotive based digital testing equipment, but they were also aware that their students were far more advanced in information technology than they were. This may have generated tensions and resistance from the older generation of teacher when adopting any new technology.The overall outcome was positive. Teachers were pleased with this training in an automotive context, because it was first time they had received generic technological training. The attendees felt it was important because the training sessions were targeted directly to them. The collected survey results provided information about what vocational teachers are actually missing in practice. In the conceptual part of this paper we discuss motivation to learn [2,3] and adult education. In the empirical part of this paper we introduce the training method utilized and finally discuss the presented outcomes and conclusions of the survey data.
|
|
| 10. |
- Turunen, Mikael, et al.
(författare)
-
Hyperosmolaric contrast agents in cartilage tomography may expose cartilage to overload-induced cell death.
- 2012
-
Ingår i: Journal of Biomechanics. - : Elsevier. - 0021-9290 .- 1873-2380. ; 45:3, s. 497-503
-
Tidskriftsartikel (refereegranskat)abstract
- In clinical arthrographic examination, strong hypertonic contrast agents are injected directly into the joint space. This may reduce the stiffness of articular cartilage, which is further hypothesized to lead to overload-induced cell death. We investigated the cell death in articular cartilage while the tissue was compressed in situ in physiological saline solution and in full strength hypertonic X-ray contrast agent Hexabrix(TM). Samples were prepared from bovine patellae and stored in Dulbecco's Modified Eagle's Medium overnight. Further, impact tests with or without creep were conducted for the samples with contact stresses and creep times changing from 1 MPa to 10 MPa and from 0 min to 15 min, respectively. Finally, depth-dependent cell viability was assessed with a confocal microscope. In order to characterize changes in the biomechanical properties of cartilage as a result of the use of Hexabrix™, stress-relaxation tests were conducted for the samples immersed in Hexabrix™ and phosphate buffered saline (PBS). Both dynamic and equilibrium modulus of the samples immersed in Hexabrix™ were significantly (p<0.05) lower than those of the samples immersed in PBS. Cartilage samples immersed in physiological saline solution showed load-induced cell death primarily in the superficial and middle zones. However, under high 8-10 MPa contact stresses, the samples immersed in full strength Hexabrix™ showed significantly (p<0.05) higher number of dead cells than the samples compressed in physiological saline, especially in the deep zone of cartilage. In conclusion, excessive loading stresses followed by tissue creep might increase the risk for chondrocyte death in articular cartilage when immersed in hypertonic X-ray contrast agent, especially in the deep zone of cartilage.
|
|
| 11. |
- Turunen, Siru, et al.
(författare)
-
Hypotonic challenge modulates cell volumes differently in the superficial zone of intact articular cartilage and cartilage explant.
- 2012
-
Ingår i: Biomechanics and Modeling in Mechanobiology. - : Springer. - 1617-7959 .- 1617-7940. ; 11:5, s. 665-75
-
Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to evaluate the effect of sample preparation on the biomechanical behaviour of chondrocytes. We compared the volumetric and dimensional changes of chondrocytes in the superficial zone (SZ) of intact articular cartilage and cartilage explant before and after a hypotonic challenge. Calcein-AM labelled SZ chondrocytes were imaged with confocal laser scanning microscopy through intact cartilage surfaces and through cut surfaces of cartilage explants. In order to clarify the effect of tissue composition on cell volume changes, Fourier Transform Infrared microspectroscopy was used for estimating the proteoglycan and collagen contents of the samples. In the isotonic medium (300 mOsm), there was a significant difference (p < 0.05) in the SZ cell volumes and aspect ratios between intact cartilage samples and cartilage explants. Changes in cell volumes at both short-term (2 min) and long-term (2 h) time points after the hypotonic challenge (180 mOsm) were significantly different (p < 0.05) between the groups. Further, proteoglycan content was found to correlate significantly (r(2) = 0.63, p < 0.05) with the cell volume changes in cartilage samples with intact surfaces. Collagen content did not correlate with cell volume changes. The results suggest that the biomechanical behaviour of chondrocytes following osmotic challenge is different in intact cartilage and in cartilage explant. This indicates that the mechanobiological responses of cartilage and cell signalling may be significantly dependent on the integrity of the mechanical environment of chondrocytes.
|
|
| 12. |
- Turunen, Siru, et al.
(författare)
-
The effect of collagen degradation on chondrocyte volume and morphology in bovine articular cartilage following a hypotonic challenge
- 2013
-
Ingår i: Biomechanics and Modeling in Mechanobiology. - : Springer. - 1617-7959 .- 1617-7940. ; 12:3, s. 417-429
-
Tidskriftsartikel (refereegranskat)abstract
- Collagen degradation is one of the early signs of osteoarthritis. It is not known how collagen degradation affects chondrocyte volume and morphology. Thus, the aim of this study was to investigate the effect of enzymatically induced collagen degradation on cell volume and shape changes in articular cartilage after a hypotonic challenge. Confocal laser scanning microscopy was used for imaging superficial zone chondrocytes in intact and degraded cartilage exposed to a hypotonic challenge. Fourier transform infrared microspectroscopy, polarized light microscopy, and mechanical testing were used to quantify differences in proteoglycan and collagen content, collagen orientation, and biomechanical properties, respectively, between the intact and degraded cartilage. Collagen content decreased and collagen orientation angle increased significantly (p < 0.05) in the superficial zone cartilage after collagenase treatment, and the instantaneous modulus of the samples was reduced significantly (p < 0.05). Normalized cell volume and height 20 min after the osmotic challenge (with respect to the original volume and height) were significantly (p < 0.001 and p < 0.01, respectively) larger in the intact compared to the degraded cartilage. These findings suggest that the mechanical environment of chondrocytes, specifically collagen content and orientation, affects cell volume and shape changes in the superficial zone articular cartilage when exposed to osmotic loading. This emphasizes the role of collagen in modulating cartilage mechanobiology in diseased tissue.
|
|
