| 1. |
- Kaput, J, et al.
(författare)
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The case for strategic international alliances to harness nutritional genomics for public and personal health
- 2005
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Ingår i: The British journal of nutrition. - : Cambridge University Press (CUP). - 0007-1145 .- 1475-2662. ; 94:5, s. 623-632
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Tidskriftsartikel (refereegranskat)abstract
- Nutrigenomics is the study of how constituents of the diet interact with genes, and their products, to alter phenotype and, conversely, how genes and their products metabolise these constituents into nutrients, antinutrients, and bioactive compounds. Results from molecular and genetic epidemiological studies indicate that dietary unbalance can alter gene–nutrient interactions in ways that increase the risk of developing chronic disease. The interplay of human genetic variation and environmental factors will make identifying causative genes and nutrients a formidable, but not intractable, challenge. We provide specific recommendations for how to best meet this challenge and discuss the need for new methodologies and the use of comprehensive analyses of nutrient–genotype interactions involving large and diverse populations. The objective of the present paper is to stimulate discourse and collaboration among nutrigenomic researchers and stakeholders, a process that will lead to an increase in global health and wellness by reducing health disparities in developed and developing countries.
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| 2. |
- Stefansson, S. O., et al.
(författare)
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Molecular mechanisms of continuous light inhibition of Atlantic salmon parr–smolt transformation
- 2007
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486. ; 273:2-3, s. 235-245
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Tidskriftsartikel (refereegranskat)abstract
- Atlantic salmon (Salmo salar) rely on changes in photoperiod for the synchronization of the developmental events constituting the parr–smolt transformation. In the absence of photoperiod cues, parr–smolt transformation is incomplete, and such ‘pseudo-smolts’ normally fail to adapt to seawater. The present study addresses the endocrine and molecular mechanisms controlling the development of hypo-osmoregulatory ability and how artificial photoperiod can disrupt these changes. Juvenile Atlantic salmon reared under constant light (LL) from first feeding, were separated into two groups, and exposed to either LL or simulated natural photoperiod (LDN) from October, eight months prior to the expected completion of smoltification. Juveniles reared on LL grew well, but failed to show the smolt-related reduction in condition factor in spring. Gill mRNA levels of Na+, K+–ATPase (NKA) isoform α1a decreased in LDN fish through completion of parr–smolt transformation, while levels remained unchanged in the LL group. In contrast, α1b expression increased 6-fold in the LDN group between February and May, again with no change in the LL group. Further, Na+, K+, 2Cl− co-transporter (NKCC) showed a transient increase in expression in smolts on LDN between February and May, while no changes in mRNA levels were seen in juveniles under LL. Consequently, gill NKA activity and NKA α and NKCC protein abundance were significantly lower in juveniles on LL than in smolts on LDN. LL fish in spring had lower circulating levels of thyroid hormones (THs), growth hormone (GH) and cortisol. Gill GH-receptor mRNA levels, determined by quantitative PCR, were less than 50% of controls. In contrast, circulating levels of IGF-1 and gill IGF-1 receptor expression, were comparable to controls. Our findings show that continuous light prevents the completion of parr–smolt transformation at a very basic level, disrupting the natural up-regulation of key elements of the endocrine system involved in the regulation of the parr–smolt transformation, and consequently inhibiting the smoltification-related increase in expression, abundance and activity of gill ion transport proteins.
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| 3. |
- Stefansson, S. O., et al.
(författare)
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Growth, osmoregulation and endocrine changes in wild Atlantic salmon smolts and post-smolts during marine migration
- 2012
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486. ; 362, s. 127-136
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Tidskriftsartikel (refereegranskat)abstract
- We have examined physiological parameters associated with seawater adaptability, growth and energetics, as well as major endocrine regulators of these processes in wild migrating Atlantic salmon smolts and post-smolts from the river through the fjord, coastal areas and the open ocean. Muscle RNA/DNA ratio suggests that growth rate increases soon after entry into seawater and continues to increase after the post-smolts reach the offshore banks and the feeding grounds in the Norwegian Sea. Post-smolts prioritize rapid growth and protein deposition in spring and summer, and their energy intake during this period is so high that deposition of energy is possible in addition to muscle growth. An increase in thyroxine (T-4) and triiodothyronine (T-3) levels was observed, suggesting a major activation of hepatic conversion of T-4 to T-3 in post-smolts in seawater, probably related to the high metabolic activity and rapid growth and development of the post-smolts. Decreased plasma growth hormone (GH) levels were observed from the river through the fjord, with levels around 2 ng ml(-1) in rapidly growing post-smolts, concurrent with an increase in circulating insulin-like growth factor I (IGF-I). An increase in pituitary GH expression levels and hepatic GH receptor (GH-R) and local IGF-I mRNA levels suggest a physiological basis for the changes in circulating GH and IGF-I levels. Receptor expression in brain and pituitary suggests that both hormones are actively involved in the growth and differentiation of these tissues during the critical early marine phase. Gill Na+, K+-ATPase (NKA) activity increased to post-smolt levels above 20 mu mol ADP mg prot.(divided by 1) h(divided by 1), probably representing long-term NKA activity levels of Atlantic salmon in seawater. Concurrent with the changes in NKA activity the expression of the NKA alpha 1b isoform remained high in post-smolts, while the expression of the NKA alpha 1a decreased from smolts to post-smolts. Both cystic fibrosis transmembrane conductance regulator (CFTR) I and II showed a reduction in mRNA levels from smolts to post-smolts, and remained stable at low expression levels in seawater. (c) 2011 Elsevier B.V. All rights reserved.
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| 4. |
- Stefansson, S. O., et al.
(författare)
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Smoltification
- 2008
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Ingår i: In “Fish Larval Physiology” (Finn A and Kapoor B, eds). - Enfield : Sci Publ. - 9781578083886 ; , s. 639-681
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Vindas, Marco A., et al.
(författare)
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Early life stress induces long-term changes in limbic areas of a teleost fish: the role of catecholamine systems in stress coping
- 2018
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Early life stress (ELS) shapes the way individuals cope with future situations. Animals use cognitive flexibility to cope with their ever-changing environment and this is mainly processed in forebrain areas. We investigated the performance of juvenile gilthead seabream, previously subjected to an ELS regime. ELS fish showed overall higher brain catecholaminergic (CA) signalling and lower brain derived neurotrophic factor (bdnf) and higher cfos expression in region-specific areas. All fish showed a normal cortisol and serotonergic response to acute stress. Brain dopaminergic activity and the expression of the alpha(2A) adrenergic receptor were overall higher in the fish homologue to the lateral septum (Vv), suggesting that the Vv is important in CA system regulation. Interestingly, ELS prevented post-acute stress downregulation of the alpha(2A) receptor in the amygdala homologue (Dm3). There was a lack of post-stress response in the beta(2) adrenergic receptor expression and a downregulation in bdnf in the Dm3 of ELS fish, which together indicate an allostatic overload in their stress coping ability. ELS fish showed higher neuronal activity (cfos) post-acute stress in the hippocampus homologue (Dlv) and the Dm3. Our results show clear long-term effects on limbic systems of seabream that may compromise their future coping ability to environmental challenges.
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| 6. |
- Ebbesson, L. O.E., et al.
(författare)
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Propylthiouracil-induced hypothyroidism in coho salmon, Oncorhynchus kisutch : Effects on plasma total thyroxine, total triiodothyronine, free thyroxine, and growth hormone
- 1998
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Ingår i: Fish Physiology and Biochemistry. - 0920-1742. ; 19:4, s. 305-313
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Tidskriftsartikel (refereegranskat)abstract
- Thyroid hormones transiently increase during parr-smolt transformation in coho salmon, Oncorhynchus kisutch, and are believed to trigger morphological, physiological, behavioural, and neural changes. The effectiveness of propylthiouracil (PTU) to induce hypothyroidism in smolting coho salmon was determined by immersing coho salmon, Oncorhynchus kisutch, in 30 mg 1-1 PTU from May 1, two weeks prior to the consistent annual total thyroxine (TT4) peak in mid-May, until the last sampling date. Plasma was obtained at two sampling dates from control and PTU -treated coho salmon: May 15, during the plasma TT4 peak; and May 26, after the TT4 peak. Radioimmunoassays were used to measure plasma TT4, total triiodothyronine (TT3), free thyroxine (FT4), and salmon growth hormone (sGH). The PTU -treatment inhibited the natural smoltification-related increases in plasma TT4, TT3 and GH levels compared with controls, but PTU-treatment did not affect these hormone levels when they were low. PTU -treatment increased FT4 and decreased TT3 and sGH levels in the May 26 sample. In the May 15 sample, FT4 levels were unaffected by PTU-treatment, whereas TT4 levels were decreased. These data demonstrate the ability of PTU to induce hypothyroidism in salmonids as shown by the decrease in TT4 and TT3. These data demonstrate that PTU treatment by immersion can induce hypothyroidism in salmonids as shown by: (1) the inhibition of the natural increases of TT4 and TT3; (2) the increase in FT4 levels corresponding to the lowered TT3 levels, suggesting an inhibition of thyroxine 5′-monodeiodinase activity. We also show for the first time that PTU treatment can lower plasma GH levels in salmonids. This lowering of plasma GH level is associated with the decrease in TT3 levels and the increase in FT4 levels. Lhe PLU induced lowering in GH levels may contribute to the observed changes in FT4 and TT3, since GH is known to increase thyroxine 5′-monodeiodinase activity.
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| 7. |
- Ekström, P., et al.
(författare)
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Distribution of serotonin-immunoreactive neurons in the brain of sockeye salmon fry
- 1989
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Ingår i: Journal of Chemical Neuroanatomy. - 0891-0618. ; 2:4, s. 201-213
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Tidskriftsartikel (refereegranskat)abstract
- The organization of the serotonergic cell groups in the brainstem of fishes and amphibians has received relatively little attention. It has been generally assumed that they are little differentiated and constitute a median cell column throughout the brainstem, and that laterally migrated serotonergic cell groups are largely lacking. In the present study we present evidence to the contrary. By the use of a sensitive immunocytochemical technique for the visualization of serotonin-immunoreactive (5HTir) neurons, we have been able to make a detailed delineation of the putatively serotonergic neuronal groups throughout the brain. In the epithalamus, 5HTir neurons were located in the left habenular nucleus in its dorsal subdivision. 5HTir neural elements, primarily photoreceptor cells, were present throughout the pineal organ and in some cases also in the parapineal organ. In the periventricular zones of the hypothalamus and posterior tuberculum, 5THir cerebrospinal fluid-contacting neurons were located in the paraventricular organ and in the dorsal, ventral and caudal zones of the periventricular hypothalamus. In the dorsal thalamus/synencephalon, 5THir neurons surround the tractus habenulo-interpeduncularis (fasciculus retroflexus). In the brainstem, several groups of 5HTir neurons could be discerned, that for reasons of topological similarity were named according to Lidov and Molliver a raphe pallidus/obscurus-complex (B1 and B2), raphe magnus (part of B3), median raphe (B8) possibly including raphe pontis (B5), raphe dorsalis (B4, B6 and B7), and B9. 5HTir neurons were observed in the central gray of the IVth ventricle, dorsal to the noradrenergic isthmal neurons and lateral to the brachium conjunctivum, in an area topologically equivalent with the dorsal subdivision of the locus coeruleus in mammals. In addition, small numbers of 5HTir neurons were located in the lobi faciales. Thus, the presence of well-differentiated groups of migrated serotonergic neurons is not an advanced trait of amniote brains, but may be a pattern common to all vertebrates.
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| 8. |
- Martin de la Fuente, L., et al.
(författare)
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Claudin-4 expression is associated with progression free survival in ovarian cancer, but not with chemotherapy response
- 2017
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Ingår i: International Journal of Gynecological Pathology. - 0277-1691. ; 37:2, s. 101-109
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Tidskriftsartikel (refereegranskat)abstract
- The tight junction protein claudin-4 has been reported to be overexpressed in advanced ovarian cancer. We investigated the prognostic significance of claudin-4 overexpression and whether claudin-4 expression could predict platinum response in primary ovarian carcinoma (OC). Claudin-4 expression was evaluated by immunohistochemistry in a tissue microarray of 140 OCs. Multivariable Cox-regression models were used to assess the effect of claudin-4 overexpression on progression-free survival and overall survival (OS). Kaplan-Meier survival analyses and the logrank test were performed comparing claudin-4 high and low groups. The association between claudin-4 expression and platinum resistance was assessed using risk ratios and the Pearson χ 2 test. A dataset of >1500 epithelial ovarian cancers was used to study the association between CLDN4 mRNA and survival. Of 140 evaluable cases, 71 (51%) displayed high claudin-4 expression. Claudin-4 overexpression predicted shorter 5-yr progression-free survival and OS in univariable analyses [hazard ratio (HR)=1.6 (1.1-2.5), P=0.020 and HR=1.6 (1.0-2.4), P=0.041, respectively]. Hazard of relapse was similar [HR=1.5 (1.0-2.4)] after adjustment for age, stage, type, and BRCA1/2 status in a multivariable analysis, but the evidence was slightly weaker (P=0.076). Validation in an external cohort confirmed the association between high expression of CLDN4 and poor 10-yr OS [HR=1.3 (1.1-1.5), P<0.001]. However, no confident association between claudin-4 and platinum sensitivity was found in our cohort [risk ratio=1.2 (0.7-2.0), P=0.3]. These findings suggest that high expression of claudin-4 may have a prognostic value in OC. The role of claudin-4 in the development of platinum resistance remains unclear.
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| 9. |
- Nilsen, Tom O, et al.
(författare)
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Differential expression of gill Na+,K+-ATPase alpha- and beta-subunits, Na+,K+,2Cl- cotransporter and CFTR anion channel in juvenile anadromous and landlocked Atlantic salmon Salmo salar.
- 2007
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Ingår i: The Journal of experimental biology. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 210:Pt 16, s. 2885-96
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Tidskriftsartikel (refereegranskat)abstract
- This study examines changes in gill Na(+),K(+)-ATPase (NKA) alpha- and beta-subunit isoforms, Na(+),K(+),2Cl(-) cotransporter (NKCC) and cystic fibrosis transmembrane conductance regulator (CFTR I and II) in anadromous and landlocked strains of Atlantic salmon during parr-smolt transformation, and after seawater (SW) transfer in May/June. Gill NKA activity increased from February through April, May and June among both strains in freshwater (FW), with peak enzyme activity in the landlocked salmon being 50% below that of the anadromous fish in May and June. Gill NKA-alpha1b, -alpha3, -beta(1) and NKCC mRNA levels in anadromous salmon increased transiently, reaching peak levels in smolts in April/May, whereas no similar smolt-related upregulation of these transcripts occurred in juvenile landlocked salmon. Gill NKA-alpha1a mRNA decreased significantly in anadromous salmon from February through June, whereas alpha1a levels in landlocked salmon, after an initial decrease in April, remained significantly higher than those of the anadromous smolts in May and June. Following SW transfer, gill NKA-alpha1b and NKCC mRNA increased in both strains, whereas NKA-alpha1a decreased. Both strains exhibited a transient increase in gill NKA alpha-protein abundance, with peak levels in May. Gill alpha-protein abundance was lower in SW than corresponding FW values in June. Gill NKCC protein abundance increased transiently in anadromous fish, with peak levels in May, whereas a slight increase was observed in landlocked salmon in May, increasing to peak levels in June. Gill CFTR I mRNA levels increased significantly from February to April in both strains, followed by a slight, though not significant increase in May and June. CFTR I mRNA levels were significantly lower in landlocked than anadromous salmon in April/June. Gill CFTR II mRNA levels did not change significantly in either strain. Our findings demonstrates that differential expression of gill NKA-alpha1a, -alpha1b and -alpha3 isoforms may be important for potential functional differences in NKA, both during preparatory development and during salinity adjustments in salmon. Furthermore, landlocked salmon have lost some of the unique preparatory upregulation of gill NKA, NKCC and, to some extent, CFTR anion channel associated with the development of hypo-osmoregulatory ability in anadromous salmon.
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| 10. |
- Nilsen, Tom O, et al.
(författare)
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Endocrine systems in juvenile anadromous and landlocked Atlantic salmon (Salmo salar): seasonal development and seawater acclimation.
- 2008
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Ingår i: General and comparative endocrinology. - : Elsevier BV. - 0016-6480. ; 155:3, s. 762-72
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Tidskriftsartikel (refereegranskat)abstract
- The present study compares developmental changes in plasma levels of growth hormone (GH), insulin-like growth factor I (IGF-I) and cortisol, and mRNA levels of their receptors and the prolactin receptor (PRLR) in the gill of anadromous and landlocked Atlantic salmon during the spring parr-smolt transformation (smoltification) period and following four days and one month seawater (SW) acclimation. Plasma GH and gill GH receptor (GHR) mRNA levels increased continuously during the spring smoltification period in the anadromous, but not in landlocked salmon. There were no differences in plasma IGF-I levels between strains, or any increase during smoltification. Gill IGF-I and IGF-I receptor (IGF-IR) mRNA levels increased in anadromous salmon during smoltification, with no changes observed in landlocked fish. Gill PRLR mRNA levels remained stable in both strains during spring. Plasma cortisol levels in anadromous salmon increased 5-fold in May and June, but not in landlocked salmon. Gill glucocorticoid receptor (GR) mRNA levels were elevated in both strains at the time of peak smoltification in anadromous salmon, while mineralocorticoid receptor (MR) mRNA levels remained stable. Only anadromous salmon showed an increase of gill 11beta-hydroxysteroid dehydrogenase type-2 (11beta-HSD2) mRNA levels in May. GH and gill GHR mRNA levels increased in both strains following four days of SW exposure in mid-May, whereas only the anadromous salmon displayed elevated plasma GH and GHR mRNA after one month in SW. Plasma IGF-I increased after four days in SW in both strains, decreasing in both strains after one month in SW. Gill IGF-I mRNA levels were only increased in landlocked salmon after 4days in SW. Gill IGF-IR mRNA levels in SW did not differ from FW levels in either strain. Gill PRLR mRNA did not change after four days of SW exposure, and decreased in both strains after one month in SW. Plasma cortisol levels did not change following SW exposure in either strain. Gill GR, 11beta-HSD2 and MR mRNA levels increased after four days in SW in both strains, whereas only the anadromous strain maintained elevated gill GR and 11beta-HSD2 mRNA levels after one month in SW. The results indicate that hormones and receptors of the GH and cortisol axes are present at significantly lower levels during spring development and SW acclimation in landlocked relative to anadromous salmon. These findings suggest that attenuation of GH and cortisol axes may, at least partially, result in reduced preparatory upregulation of key gill ion-secretory proteins, possibly a result of reduced selection pressure for marine adaptations in landlocked salmon.
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| 11. |
- Vult von Steyern, Per, et al.
(författare)
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Fracture strength of two oxide ceramic crown systems after cyclic pre-loading and thermocycling
- 2006
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Ingår i: Journal of Oral Rehabilitation. - : Wiley. - 1365-2842 .- 0305-182X. ; 33:9, s. 682-689
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to investigate the fracture resistance of zirconia crowns and to compare the results with crowns made of a material with known clinical performance (alumina) in away that reflects clinical aspects. Sixty crowns were made, 30 identical crowns of alumina and 30 of zirconia. Each group of 30 was randomly divided into three groups of 10 crowns that were to undergo different treatments: (i) water storage only, (ii) pre-loading (10 000 cycles, 30-300 N, 1 Hz), (iii) thermocycling (5-55 degrees , 5000 cycles) + pre-loading (10 000 cycles, 30-300 N, 1 Hz). Subsequently, all 60 crowns were subjected to load until fracture occurred. There were two types of fracture: total fracture and partial fracture. Fracture strengths (N) were: group 1, alumina 905/zirconia 975 (P = 0.38); group 2, alumina 904/zirconia 1108 (P < 0.007) and group 3, alumina 917/zirconia 910 (P > 0.05). Total fractures were more frequent in the alumina group (P < 0.01). Within the limitations of this in vitro study, it can be concluded that there is no difference in fracture strength between crowns made with zirconia cores compared with those made of alumina if they are subjected to load without any cyclic pre-load or thermocycling. There is, however, a significant difference (P = 0.01) in the fracture mode, suggesting that the zirconia core is stronger than the alumina core. Crowns made with zirconia cores have significantly higher fracture strengths after pre-loading.
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