| 1. |
- Macias Garcia, B, et al.
(författare)
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Toxicity of glycerol for the stallion spermatozoa: Effects on membrane integrity and cytoskeleton, lipid peroxidation and mitochondrial membrane potential
- 2012
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Ingår i: Theriogenology. - : Elsevier. - 0093-691X .- 1879-3231. ; 77:7, s. 1280-1289
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Tidskriftsartikel (refereegranskat)abstract
- Glycerol is, to date, the most widely used cryoprotectant to freeze stallion spermatozoa at concentrations between 2% and 5%. Cryoprotectant toxicity has been claimed to be the single most limiting factor for the success of cryopreservation. In order to evaluate the toxic effects of the concentrations of glycerol used in practice, stallion spermatozoa were incubated in Biggers Whitten and Whittingham (BWW) media supplemented with 0%, 0.5%, 1.5%, 2.5%, 3.5%, and 5% glycerol. In two additional experiments, a hyposmotic (75 mOsm/kg) and a hyperosmotic (900 mOsm/kg) control media were included. Sperm parameters evaluated included cell volume, membrane integrity, lipid peroxidation, caspase 3, 7, and 8 activation, mitochondrial membrane potential, and integrity of the cytoskeleton. Glycerol exerted toxicity at concentrations 3.5% and the maximal toxicity was observed at 5%. The actin cytoskeleton was especially sensitive to glycerol presence, inducing rapid F actin depolymerization at concentrations over 1.5%. The sperm membrane and the mitochondria were other structures affected. The toxicity of glycerol is apparently related to osmotic and nonosmotic effects. In view of our results the concentration of glycerol in the freezing media for stallion spermatozoa should not surpass 2.5%.
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| 2. |
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| 3. |
- Bach, Dominik R., et al.
(författare)
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Human Hippocampus Arbitrates Approach-Avoidance Conflict
- 2014
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 24:5, s. 541-547
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Tidskriftsartikel (refereegranskat)abstract
- Animal models of human anxiety often invoke a conflict between approach and avoidance [1, 2]. In these, a key behavioral assay comprises passive avoidance of potential threat and inhibition, both thought to be controlled by ventral hippocampus [2-6]. Efforts to translate these approaches to clinical contexts [7, 8] are hampered by the fact that it is not known whether humans manifest analogous approach-avoidance dispositions and, if so, whether they share a homologous neurobiological substrate [9]. Here, we developed a paradigm to investigate the role of human hippocampus in arbitrating an approach-avoidance conflict under varying levels of potential threat. Across four experiments, subjects showed analogous behavior by adapting both passive avoidance behavior and behavioral inhibition to threat level. Using functional magnetic resonance imaging (fMRI), we observe that threat level engages the anterior hippocampus, the human homolog of rodent ventral hippocampus [10]. Testing patients with selective hippocampal lesions, we demonstrate a causal role for the hippocampus with patients showing reduced passive avoidance behavior and inhibition across all threat levels. Our data provide the first human assay for approach-avoidance conflict akin to that of animal anxiety models. The findings bridge rodent and human research on passive avoidance and behavioral inhibition and furnish a framework for addressing the neuronal underpinnings of human anxiety disorders, where our data indicate a major role for the hippocampus.
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| 4. |
- Boij, Mats, et al.
(författare)
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On the Weak Lefschetz Property for artinian Gorenstein algebras of codimension three
- 2014
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Ingår i: Journal of Algebra. - : Elsevier BV. - 0021-8693 .- 1090-266X. ; 403, s. 48-68
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Tidskriftsartikel (refereegranskat)abstract
- We study the problem of whether an arbitrary codimension three graded artinian Gorenstein algebra has the Weak Lefschetz Property. We reduce this problem to checking whether it holds for all compressed Gorenstein algebras of odd socle degree. In the first open case, namely Hilbert function (1, 3, 6, 6, 3, 1), we give a complete answer in every characteristic by translating the problem to one of studying geometric aspects of certain morphisms from P2 to P3, and Hesse configurations in P2.
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| 5. |
- Chirouze, C., et al.
(författare)
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Enterococcal endocarditis in the beginning of the 21st century: analysis from the International Collaboration on Endocarditis-Prospective Cohort Study
- 2013
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1198-743X. ; 19:12, s. 1140-1147
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Tidskriftsartikel (refereegranskat)abstract
- Enterococci are reportedly the third most common group of endocarditis-causing pathogens but data on enterococcal infective endocarditis (IE) are limited. The aim of this study was to analyse the characteristics and prognostic factors of enterococcal IE within the International Collaboration on Endocarditis. In this multicentre, prospective observational cohort study of 4974 adults with definite IE recorded from June 2000 to September 2006, 500 patients had enterococcal IE. Their characteristics were described and compared with those of oral and group D streptococcal IE. Prognostic factors for enterococcal IE were analysed using multivariable Cox regression models. The patients' mean age was 65years and 361/500 were male. Twenty-three per cent (117/500) of cases were healthcare related. Enterococcal IE were more frequent than oral and group D streptococcal IE in North America. The 1-year mortality rate was 28.9% (144/500). E.faecalis accounted for 90% (453/500) of enterococcal IE. Resistance to vancomycin was observed in 12 strains, eight of which were observed in North America, where they accounted for 10% (8/79) of enterococcal strains, and was more frequent in E.faecium than in E.faecalis (3/16 vs. 7/364 , p0.01). Variables significantly associated with 1-year mortality were heart failure (HR 2.4, 95% CI 1.73.5, p<0.0001), stroke (HR 1.9, 95% CI 1.32.8, p0.001) and age (HR 1.02 per 1-year increment, 95% CI 1.011.04, p0.002). Surgery was not associated with better outcome. Enterococci are an important cause of IE, with a high mortality rate. Healthcare association and vancomycin resistance are common in particular in North America.
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| 6. |
- Lipinski, Michael J., et al.
(författare)
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A Systematic Review and Collaborative Meta-Analysis to Determine the Incremental Value of Copeptin for Rapid Rule-Out of Acute Myocardial Infarction
- 2014
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Ingår i: American Journal of Cardiology. - : Elsevier BV. - 0002-9149 .- 1879-1913. ; 113:9, s. 1581-1591
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Tidskriftsartikel (refereegranskat)abstract
- Multiple studies have evaluated copeptin, a surrogate for arginine vasopressin, in the diagnosis of acute myocardial infarction (AMI) with mixed results. A systematic review and collaborative meta-analysis were performed for diagnosis of AMI and assessment of prognosis in patients presenting to the emergency department with chest pain. MEDLINE/PubMed, Cochrane CENTRAL, and EMBASE were searched for studies assessing copeptin in such patients. Study investigators were contacted, and many provided previously unpublished data. Random-effects methods were used to compare the data for copeptin, troponin, and their combination. There were a total of 9,244 patients from the 14 included studies. Mean age was 62 years; 64% were men; and 18.4% were ultimately diagnosed with AMI. Patients with AMI had a higher presentation copeptin level than those without AMI (22.8 vs 8.3 pmol/L, respectively, p <0.001). Although troponin had better diagnostic accuracy than copeptin for AMI, the combination of copeptin and troponin significantly improved the sensitivity (0.905 [0.888 to 0.921] vs 0.686 [0.661 to 0.710], respectively, p <0.001) and negative predictive value (0.97 [0.964 to 0.975] vs 0.93 [0.924 to 0.936], respectively, p <0.001) compared with troponin alone. Elevation in copeptin carried a similar risk of all-cause mortality to an elevation in troponin (odds ratio 5.84 vs 6.74, respectively, p = 0.67). In conclusion, copeptin not only identifies patients at risk of all-cause mortality, but its addition to troponin improved the sensitivity and negative likelihood ratio for diagnosis of AMI compared with troponin alone. Thus, copeptin may help identify patients who may be safely discharged early from the emergency department.
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| 7. |
- Macías García, Beatriz, et al.
(författare)
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The mitochondria of stallion spermatozoa are more sensitive than the plasmalemma to osmotic induced stress: role of c-Jun N-terminal Kinase (JNKs) pathway
- 2012
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Ingår i: Journal of Andrology. - Schaumburg, IL, United States : American Society of Andrology. - 0196-3635 .- 1939-4640. ; 33:1, s. 105-113
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Tidskriftsartikel (refereegranskat)abstract
- Cryopreservation introduces extreme temperature and osmolality changes that impart lethal and sublethal effects on spermatozoa. Additionally, there is evidence that the osmotic stress induced by cryopreservation causes oxidative stress to spermatozoa. The main sources of reactive oxygen species in mammalian sperm are the mitochondria. In view of this, the aim of our study was to test whether or not osmotic stress was able to induce mitochondrial damage and to explore the osmotic tolerance of the mitochondria of stallion spermatozoa. Ejaculates from 7 stallions were subjected to osmolalities ranging from 75 to 1500 mOsm/kg, and the effect on sperm membrane integrity and mitochondrial membrane potential was studied. Additionally, the effects of changes in osmolality from hyposmotic to isosmotic and from hyperosmotic to isosmotic solutions were studied (osmotic excursions). The cellular volume of stallion spermatozoa under isosmotic conditions was 20.4 ± 0.33 μm3. When exposed to low osmolality, the stallion spermatozoa behaved like a linear osmometer, whereas exposure to high osmolalities up to 900 mOsm/kg resulted in decreased sperm volume. Although sperm membranes were relatively resistant to changes in osmolality, mitochondrial membrane potential decreased when osmolalities were low or very high (10.7 ± 1.74 and 16.5 ± 1.70 at 75 and 150 mOsm/kg, respectively, and 13.1 ± 1.83 at 1500 mOsm/kg), whereas in isosmolar controls the percentage of stallion sperm mitochondria with a high membrane potential was 41.1 ± 1.69 (P < .01). Osmotic excursions induced greater damage than exposure of spermatozoa to a given nonphysiologic osmolality, and again the mitochondria were more prone to damage induced by osmotic excursions than was the sperm plasma membrane. In search of intracellular components that could mediate these changes, we have detected for the first time the c-Jun N-terminal kinase 1/2 in stallion spermatozoa, which are apparently involved in the regulation of the viability of these cells.
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| 8. |
- Patel, M., et al.
(författare)
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Language for learning complex human-object interactions
- 2013
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Ingår i: 2013 IEEE International Conference on Robotics and Automation (ICRA). - : IEEE Computer Society. - 9781467356411 ; , s. 4997-5002
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Konferensbidrag (refereegranskat)abstract
- In this paper we use a Hierarchical Hidden Markov Model (HHMM) to represent and learn complex activities/task performed by humans/robots in everyday life. Action primitives are used as a grammar to represent complex human behaviour and learn the interactions and behaviour of human/robots with different objects. The main contribution is the use of a probabilistic model capable of representing behaviours at multiple levels of abstraction to support the proposed hypothesis. The hierarchical nature of the model allows decomposition of the complex task into simple action primitives. The framework is evaluated with data collected for tasks of everyday importance performed by a human user.
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| 9. |
- Planas, Nora, et al.
(författare)
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Electronic Structure of Oxidized Complexes Derived from cis-Ru(II)(bpy)(2)(H(2)O)(2)](2+) and Its Photoisomerization Mechanism
- 2011
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Ingår i: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 50:21, s. 11134-11142
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Tidskriftsartikel (refereegranskat)abstract
- The geometry and electronic structure of cis-[Ru(II)(bpy)(2)(H(2)O)(2)](2+) and its higher oxidation state species up formally to Ru(VI) have been studied by means of UV-vis, EPR, XAS, and DFT and CASSCF/CASPT2 calculations. DFT calculations of the molecular structures of these species show that, as the oxidation state increases, the Ru-O bond distance decreases, indicating increased degrees of Ru-O multiple bonding. In addition, the O-Ru-O valence bond angle increases as the oxidation state increases. EPR spectroscopy and quantum chemical calculations indicate that low-spin configurations are favored for all oxidation states. Thus, cis-[Ru(IV)(bpy)(2)(OH)(0)](2+) (d(4)) has a singlet ground state and is EPR-silent at low temperatures, while cis-[Ru(V)(bpy)(2)(O)(OH)](2+) (d(3)) has a doublet ground state. XAS spectroscopy of higher oxidation state species and DFT calculations further illuminate the electronic structures of these complexes, particularly with respect to the covalent character of the O-Ru-O fragment. In addition, the photochemical isomerization of cis-[Ru(II)(bpy)(2)(H(2)O)(2)](2+) to its trans-[Ru(II)(bpy)(2)(H(2)O)(2)](2+) isomer has been fully characterized through quantum chemical calculations. The excited-state process is predicted to involve decoordination of one aqua ligand, which leads to a coordinatively unsaturated complex that undergoes structural rearrangement followed by recoordination of water to yield the trans isomer.
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