| 1. |
- Moser, Markus, et al.
(författare)
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Ultrastructural cartilage abnormalities in MIA/CD-RAP-deficient mice
- 2002
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Ingår i: Molecular and Cellular Biology. - 0270-7306. ; 22:5, s. 1438-1445
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Tidskriftsartikel (refereegranskat)abstract
- MIA/CD-RAP is a small, soluble protein secreted from malignant melanoma cells and from chondrocytes. Recent evidence has identified MIA/CD-RAP as the prototype of a small family of extracellular proteins adopting an SH3 domain-like fold. It is thought that interaction between MIA/CD-RAP and specific epitopes in extracellular matrix proteins regulates the attachment of tumor cells and chondrocytes. In order to study the consequences of MIA/CD-RAP deficiency in vivo, we generated mice with a targeted gene disruption. The complete absence of MIA/CD-RAP mRNA and protein expression was demonstrated by reverse transcriptase, Western blot analysis, and enzyme-linked immunosorbent assay measurements of whole-embryo extracts. MIA-/- mice were viable and developed normally, and histological examination of the organs by means of light microscopy revealed no major abnormalities. In contrast, electron microscopic studies of cartilage composition revealed subtle defects in collagen fiber density, diameter, and arrangement, as well as changes in the number and morphology of chondrocytic microvilli. Taken together, our data indicate that MIA/CD-RAP is essentially required for formation of the highly ordered ultrastructural fiber architecture in cartilage and may have a role in regulating chondrocyte matrix interactions.
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| 2. |
- Zamora, Juan Carlos, et al.
(författare)
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Considerations and consequences of allowing DNA sequence data as types of fungal taxa
- 2018
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Ingår i: IMA Fungus. - : INT MYCOLOGICAL ASSOC. - 2210-6340 .- 2210-6359. ; 9:1, s. 167-185
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Tidskriftsartikel (refereegranskat)abstract
- Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11th International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.
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| 3. |
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| 4. |
- Nass, Karol, et al.
(författare)
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Indications of radiation damage in ferredoxin microcrystals using high-intensity X-FEL beams
- 2015
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Ingår i: Journal of Synchrotron Radiation. - 0909-0495 .- 1600-5775. ; 22:2, s. 225-238
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Tidskriftsartikel (refereegranskat)abstract
- Proteins that contain metal cofactors are expected to be highly radiation sensitive since the degree of X-ray absorption correlates with the presence of high-atomic-number elements and X-ray energy. To explore the effects of local damage in serial femtosecond crystallography (SFX), Clostridium ferredoxin was used as a model system. The protein contains two [4Fe–4S] clusters that serve as sensitive probes for radiation-induced electronic and structural changes. High-dose room-temperature SFX datasets were collected at the Linac Coherent Light Source of ferredoxin microcrystals. Difference electron density maps calculated from high-dose SFX and synchrotron data show peaks at the iron positions of the clusters, indicative of decrease of atomic scattering factors due to ionization. The electron density of the two [4Fe–4S] clusters differs in the FEL data, but not in the synchrotron data. Since the clusters differ in their detailed architecture, this observation is suggestive of an influence of the molecular bonding and geometry on the atomic displacement dynamics following initial photoionization. The experiments are complemented by plasma code calculations.
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| 5. |
- Nyblom, Maria, et al.
(författare)
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Crystal Structure of Na+, K+-ATPase in the Na+-Bound State
- 2013
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 342:6154, s. 123-127
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Tidskriftsartikel (refereegranskat)abstract
- The Na+, K+-adenosine triphosphatase (ATPase) maintains the electrochemical gradients of Na+ and K+ across the plasma membrane-a prerequisite for electrical excitability and secondary transport. Hitherto, structural information has been limited to K+-bound or ouabain-blocked forms. We present the crystal structure of a Na+-bound Na+, K+-ATPase as determined at 4.3 angstrom resolution. Compared with the K+-bound form, large conformational changes are observed in the a subunit whereas the beta and gamma subunit structures are maintained. The locations of the three Na+ sites are indicated with the unique site III at the recently suggested IIIb, as further supported by electrophysiological studies on leak currents. Extracellular release of the third Na+ from IIIb through IIIa, followed by exchange of Na+ for K+ at sites I and II, is suggested.
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| 6. |
- Sommerlade, Linda, et al.
(författare)
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GRADING OF DYNAMIC CEREBRAL AUTOREGULATION WITHOUT BLOOD PRESSURE RECORDINGS: A SIMPLE DOPPLER-BASED METHOD
- 2012
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Ingår i: Ultrasound in Medicine and Biology. - : Elsevier. - 0301-5629 .- 1879-291X. ; 38:9, s. 1546-1551
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Tidskriftsartikel (refereegranskat)abstract
- Transcranial Doppler sonography allows for noninvasive assessment of dynamic cerebral autoregulation. A wider clinical use of this approach has been hampered by the need for continuous arterial blood pressure (ABP) measurements. We describe a new method of a pure Doppler signal based estimation of dynamic autoregulation using heart rate (HR) and cerebral blood flow velocity (CBFV) information. The phase between these two signals was assessed from 0.1 Hz oscillations induced by regular breathing. We compared this new approach with the standard method (phase between ABP and CBFV oscillations) in 93 patients with unilateral severe carotid artery obstruction. On a group level, the phase HR-CBFV differed significantly between ipsi- and contralateral sides (p = 0.024) and correlated significantly with the standard phase ABP-CBFV (r = 0.369, p andlt; 0.001). The proposed method can, thus, detect impaired dynamic autoregulation in occlusive carotid artery disease using a single Doppler probe.
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| 7. |
- Squires, Allison, et al.
(författare)
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A systematic survey instrument translation process for multi-country, comparative health workforce studies.
- 2013
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Ingår i: International Journal of Nursing Studies. - : Elsevier BV. - 0020-7489 .- 1873-491X. ; 50:2, s. 264-273
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: As health services research (HSR) expands across the globe, researchers will adopt health services and health worker evaluation instruments developed in one country for use in another. This paper explores the cross-cultural methodological challenges involved in translating HSR in the language and context of different health systems. OBJECTIVES: To describe the pre-data collection systematic translation process used in a twelve country, eleven language nursing workforce survey. DESIGN AND SETTINGS: We illustrate the potential advantages of Content Validity Indexing (CVI) techniques to validate a nursing workforce survey developed for RN4CAST, a twelve country (Belgium, England, Finland, Germany, Greece, Ireland, Netherlands, Norway, Poland, Spain, Sweden, and Switzerland), eleven language (with modifications for regional dialects, including Dutch, English, Finnish, French, German, Greek, Italian, Norwegian, Polish, Spanish, and Swedish), comparative nursing workforce study in Europe. PARTICIPANTS: Expert review panels comprised of practicing nurses from twelve European countries who evaluated cross-cultural relevance, including translation, of a nursing workforce survey instrument developed by experts in the field. METHODS: The method described in this paper used Content Validity Indexing (CVI) techniques with chance correction and provides researchers with a systematic approach for standardizing language translation processes while simultaneously evaluating the cross-cultural applicability of a survey instrument in the new context. RESULTS: The cross-cultural evaluation process produced CVI scores for the instrument ranging from .61 to .95. The process successfully identified potentially problematic survey items and errors with translation. CONCLUSIONS: The translation approach described here may help researchers reduce threats to data validity and improve instrument reliability in multinational health services research studies involving comparisons across health systems and language translation.
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| 8. |
- Young, Amber V., et al.
(författare)
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Inferring chemical disequilibrium biosignatures for Proterozoic Earth-like exoplanets
- 2024
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Ingår i: Nature Astronomy. - : Springer Nature. - 2397-3366. ; 8, s. 101-110
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Tidskriftsartikel (refereegranskat)abstract
- Chemical disequilibrium quantified using the available free energy has previously been proposed as a potential biosignature. However, researchers remotely sensing exoplanet biosignatures have not yet investigated how observational uncertainties impact the ability to infer a life-generated available free energy. We pair an atmospheric retrieval tool to a thermodynamics model to assess the detectability of chemical disequilibrium signatures of Earth-like exoplanets, focusing on the Proterozoic eon when the atmospheric abundances of oxygen-methane disequilibrium pairs may have been relatively high. Retrieval model studies applied across a range of gas abundances revealed that order-of-magnitude constraints on the disequilibrium energy are achieved with simulated reflected-light observations for the high-abundance scenario and high signal-to-noise ratios (50), whereas weak constraints are found for moderate signal-to-noise ratios (20-30) and medium- to low-abundance cases. Furthermore, the disequilibrium-energy constraints are improved by using the modest thermal information encoded in water vapour opacities at optical and near-infrared wavelengths. These results highlight how remotely detecting chemical disequilibrium biosignatures can be a useful and metabolism-agnostic approach to biosignature detection. Chemical disequilibrium is a known biosignature, and it is important to determine the conditions for its remote detection. A thermodynamical model coupled with atmospheric retrieval shows that a disequilibrium can be inferred for a Proterozoic Earth-like exoplanet in reflected light at a high O2/CH4 abundance case and signal-to-noise ratio of 50.
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| 9. |
- Abbafati, Cristiana, et al.
(författare)
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- 2020
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Tidskriftsartikel (refereegranskat)
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