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| 2. |
- Almstrand, Robert, et al.
(författare)
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Three-dimensional stratification of bacterial biofilm populations in a moving bed biofilm reactor for nitritation-anammox.
- 2014
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 15:2, s. 2191-206
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Tidskriftsartikel (refereegranskat)abstract
- Moving bed biofilm reactors (MBBRs) are increasingly used for nitrogen removal with nitritation-anaerobic ammonium oxidation (anammox) processes in wastewater treatment. Carriers provide protected surfaces where ammonia oxidizing bacteria (AOB) and anammox bacteria form complex biofilms. However, the knowledge about the organization of microbial communities in MBBR biofilms is sparse. We used new cryosectioning and imaging methods for fluorescence in situ hybridization (FISH) to study the structure of biofilms retrieved from carriers in a nitritation-anammox MBBR. The dimensions of the carrier compartments and the biofilm cryosections after FISH showed good correlation, indicating little disturbance of biofilm samples by the treatment. FISH showed that Nitrosomonas europaea/eutropha-related cells dominated the AOB and Candidatus Brocadia fulgida-related cells dominated the anammox guild. New carriers were initially colonized by AOB, followed by anammox bacteria proliferating in the deeper biofilm layers, probably in anaerobic microhabitats created by AOB activity. Mature biofilms showed a pronounced three-dimensional stratification where AOB dominated closer to the biofilm-water interface, whereas anammox were dominant deeper into the carrier space and towards the walls. Our results suggest that current mathematical models may be oversimplifying these three-dimensional systems and unless the multidimensionality of these systems is considered, models may result in suboptimal design of MBBR carriers.
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| 3. |
- Andersson, Felicia, et al.
(författare)
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Resedagbok England/Wales - Arkitektur & teknik 2018
- 2018
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Denna resedagbok är en del av Arkitektur och teknik- studenternas förberedelse för årskurs 3 och särskilt en träning i att söka, upptäcka och iakkta arkitekturens komplexa sammanhang och de värden som kan skapas genom arkitektur. Under studieresan byggs ett grundmaterial till dagboken upp genom förberedda presentationer, gemensamma analyser, undersökande skisser och konstnärliga övningar. Studieresan följs upp och bearbetas vid seminarier och genom korsläsning av texter där studenterna uppmanas till ett personligt reflekterande hållningssätt. På så sätt blir dagboken ett levande dokument som visar vår glädje och nyfikenhet över de många broar och byggnader vi upplevt tillsammans, och ett dokument som vill locka oss och alla läsare till vidare upptäcktsfärder.
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| 4. |
- Cardona Gomez, Maria Eugenia, et al.
(författare)
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Specific properties of shRNA-mediated CCR5 downregulation that enhance the inhibition of HIV-1 infection in combination with shRNA targeting HIV-1 rev
- 2022
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Ingår i: Molecular Biology Reports. - : Springer. - 0301-4851 .- 1573-4978. ; 49, s. 11187-11192
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Tidskriftsartikel (refereegranskat)abstract
- Treatment with RNAi against HIV-1 transcripts efficiently inhibits viral replication but induces selection of escape mutants; therefore, the CCR5 coreceptor was suggested as an additional target. Blocking viral and host transcripts improved the antiviral effect. We have used short hairpin RNA (shRNA) targeting the human CCR5 (shCCR5) or the HIV-1 rev (shRev) transcripts to demonstrate distinctive properties of anti-CCR5 shRNA: shCCR5 induced more sustained protection than shRev; partial reduction in CCR5 expression substantially decreased HIV-1 infection, and shCCR5 performed better than shRev in the mixed shRNA-treated and untreated cultures. These observations indicate that CCR5 inhibitors should be conveniently included in HIV-1 gene silencing treatment schedules when only a certain cell fraction is protected to further reduce endogenous virus in a properly ART-treated HIV-1 infected individual.
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| 5. |
- Christensson, Anders, et al.
(författare)
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Family History of Myocardial Infarction Increases Risk of Renal Dysfunction in Middle Age.
- 2014
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Ingår i: American Journal of Nephrology. - : S. Karger AG. - 1421-9670 .- 0250-8095. ; 39:2, s. 85-91
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Tidskriftsartikel (refereegranskat)abstract
- Background/Aims: Chronic kidney disease (CKD) is common in the general population, may lead to end-stage renal disease, and is most frequently found among males. Familial clustering of kidney diseases has been observed. We aimed to study a potential association between the family history of myocardial infarction (MI) and renal dysfunction. Methods: 22,297 males and 10,828 females, aged 33-60 years, from a population-based cohort study were studied. Estimated glomerular filtration rate (eGFR) was assessed by the CKD-EPI creatinine equation. Every participant filled in a self-administered questionnaire including family history. Heredity for MI was defined as mother or father having had MI and/or died from MI, and/or brother or sister having had MI. Binary logistic regression and multiple linear regression were used in the analyses. Results: Multiple linear regression revealed a significantly increased risk of renal dysfunction in those with a positive heredity for MI (the whole cohort p = 0.01, males p = 0.000, females p = 0.169). Binary logistic regression showed that males with heredity for MI with a mean age of 43 years have a 2 times higher risk (p = 0.02) of belonging to the group with GFR <45 ml/min/1.73 m(2) compared to those without heredity. For the whole cohort the increased risk was 1.6 times (p = 0.07). There was no significant association for females (p = 0.88). Conclusion: These findings demonstrate that a familial burden of MI is associated with renal dysfunction, in men, already in middle age. Genetic variants may underlie predisposition to CKD in those with heredity for MI. © 2014 S. Karger AG, Basel.
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| 6. |
- Christensson, Kyllike, et al.
(författare)
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The Challenge of Improving Perinatal Care in settings with Limited Resources : Observations of Midwifery Practices in Mozambique
- 2006
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Ingår i: African Journal of Reproductive Health. - Benin City, Edo State, Nigeria : Women's Health and Action Research Centre. - 1118-4841. ; 10:1, s. 47-61
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to observe and analyze midwifery care routine related to asphyxia and hypothermia during the perinatal period and to investigate the effect of an in-service education program. A direct non-participant pre-and post intervention observation study of midwifery a performance during childbirth was conducted at a labour ward in Maputo. The observed groups consisted of 702 and 616 midwifery –attended deliveries. Examination was also conducted of the partographs (702 vs. 616). The quality of midwifery care related to prevention and early detection of asphyxia and hypothermia was found to be inadequate and the intervention had no significant effect upon the midwives' performances. This could be attributed to the quality of the intervention itself or to failure of implementing managerial decisions such as transfer to partograph documentation from obstetricians to midwives. Change in professional performance does not automatically follow awareness of evidence-based midwifery practices, but requires behavioural change, which may be more difficult to achieve.
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| 7. |
- Christensson, Maria, et al.
(författare)
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Ontogenesis of within-session locomotor habituation in the open field.
- 2005
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Ingår i: NeuroReport. - 1473-558X. ; 16:12, s. 1319-1323
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Tidskriftsartikel (refereegranskat)abstract
- Habituation signifies a decreased response to a constant or repeated stimulus or environment. Although habituation is a fundamental form of nonassociative learning, little is known about its ontogenesis. Here, locomotor activity of postnatal ferrets within individual open field sessions was quantitatively analysed. The patterns of activity revealed a gradual shift across developmental time between relative increment and decrement of activity within sessions. The increment-to-decrement turning point was around postnatal day 48. These novel findings indicate that systematic changes in the interplay between mechanisms that drive exploratory behaviour and those that inhibit it shape the ontogenesis of open field habituation. The remarkable robustness of the data underscores the suitability of the ferret as an experimental animal for investigating ontogenesis of habituation.
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| 8. |
- Christensson, Maria
(författare)
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Ontogenetic and comparative aspects of cerebellar and motor development
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During the course of development the motor repertoire of animals and humans alike go through dramatic changes. New motor patterns arise; movements become coordinated, improve in precision and are at the same time continuously calibrated to the changing body dimensions. The cerebellum is critical for movement coordination and adaptation in adults. Also, interfering with cerebellar development during early life causes behavioural deficits suggesting an important role of the cerebellum in the formation of motor synergies. Hence, to understand the dramatic change in motor competence that characterizes postnatal development it may be of particular interest to study processes underlying the formation and shaping of the cerebellar neuronal networks. Unfortunately, little is known about how the cerebellum actually contributes to motor development. In order to elucidate the relationships between cerebellar ontogenetic changes and postnatal motor development a suitable animal model for multiple levels of analysis is a prerequisite. In this thesis, we therefore sought to develop and evaluate an experimental model that is suitable for combined behavioural, structural and systems level electrophysiological investigations of cerebellar development. For a number of reasons, the postnatal ferret seemed to be a suitable candidate. Although the ferret is commonly used as an experimental model in developmental studies on sensory systems, the development of its motor systems and motor behaviour had not been previously investigated. As a first step, we characterized the postnatal motor development in ferret kits in daily sessions from postnatal day (P)2 to P63. A battery of motor tests spanning the entire developmental period was used to assess locomotor activity and ability and the maturation of postural dynamic reflexes. Secondly, we characterized the morphological development of the ferret cerebellum. Overall cerebellar size, foliation and thickness of cortical layers were quantified and Purkinje cell morphology was characterized from P1 to P63. Thirdly, we investigated the zonal organization of climbing fibre input to the cerebella of ferret kits; a fundamental and general physiological feature of cerebellar function in the adult animal. These studies provide the first investigations of motor behavioural and cerebellar morphological development in the ferret. The electrophysiological data obtained represent a first important step towards the understanding of cerebellar physiological processes in the course of motor development. We conclude that the ferret in many aspects is a particularly suitable animal model for the study of cerebellar mechanisms underlying motor development. In a parallel approach, we assessed how timescales of motor and cerebellar morphological development can be translated between species with differently long developmental time periods, such as the ferret and rat. Linear regression analyses were performed on time points defining the corresponding levels of motor development and cerebellar maturation in ferrets and rats (rat data from Altman and Bayer, 1997). The derived time-conversion equations describing cerebellar morphological development and motor development in ferret and rat were highly congruent. To extend the comparative analysis to also include humans a model was formulated that takes into consideration comparative time courses of neurogenesis and cerebellar morphogenesis and relative timing of birth. Using behavioural data from rats and ferrets as input, the model predicts corresponding motor developmental dates that fall within 10% of actual mean values for the human population. Such astonishing predictive accuracy indicates that motor development in animals and man is governed by very similar principles and that these principles are successfully captured by our model.
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| 9. |
- Christensson, Maria, et al.
(författare)
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Time course of cerebellar morphological development in postnatal ferrets: Ontogenetic and comparative perspectives.
- 2007
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Ingår i: Journal of Comparative Neurology. - : Wiley. - 1096-9861 .- 0021-9967. ; 501:6, s. 916-930
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Tidskriftsartikel (refereegranskat)abstract
- We provide the first systematic description of the morphological ontogenesis of the ferret cerebellum and compare its relative time-course to that of the rat cerebellum. Overall cerebellar size, foliation, and thickness of cortical layers were quantified and Purkinje cell morphology was characterized at 24 timepoints in ferrets from postnatal day (P)1 to P63. The ferret cerebellum was substantially larger than that of the rat and had a much longer developmental period. In ferrets, Purkinje cells were dispersed into a monolayer by P9, the formation of folia declined abruptly around P20, and the external granular layer peaked in thickness around P22 and disappeared by P56. Timepoints of corresponding relative developmental maturity of the quantified architectural features of rat and ferret cerebella were determined and their relationship was analyzed by linear regression. The time-conversion equation derived, describing the relationship between cerebellar morphogenesis in the two species, had a determination coefficient (r2) of 0.95. Conspicuously, the equation predicted with high accuracy the timing of structural changes in individual Purkinje cells in the ferret cerebellum. The conversion equation should be useful for precise quantitative translation of data between studies of ferret and rat cerebellum and for comparisons between development of motor and sensory structures and functions in ferrets. The degree of similarity in the time-courses of cerebellar development in two distantly related mammals makes explicit in quantitative terms how remarkably conserved the cerebellum is in phylogenesis. Therefore, the methodology should be applicable to precise quantitative conversions of cerebellar developmental time-courses also between other species.
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| 10. |
- Christensson, Maria, et al.
(författare)
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Time course of postnatal motor development in ferrets: ontogenetic and comparative perspectives.
- 2005
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Ingår i: Behavioural Brain Research. - : Elsevier BV. - 0166-4328. ; 158:2, s. 231-242
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Tidskriftsartikel (refereegranskat)abstract
- We assess relative time courses of motor development in ferrets and rats and evaluate ferrets as experimental animals for studies of motor development. Motor behaviour of ferret pups was characterized in daily sessions from postnatal day (P) 2 to P63. Observations concerning rotational locomotion ('pivoting'), crawling, walking, upright standing ('rearing') and walking on a narrow path; righting on a surface, in mid-air and on an inclined plane ('geotaxis') were quantified in detail and compared with published data on rat motor development. Besides providing a comprehensive characterization of ferret motor development, our results demonstrate that relative time courses of emergence of motor skills in ferrets and rats are highly similar despite substantially different duration of postnatal periods. The relationship between species was determined by linear regression analysis of an x-y-plot of postnatal ages (y: ferret days; x: rat days) corresponding to given levels of performance of specific skills. The model equation y = 2.46x-4.18 represents the conversion between time courses of rat and ferret motor development. Remarkably, the model explained 81% of data variance (r2 = 0.81) and should hence be useful for translation of motor developmental data between ferret and rat and for comparisons between motor and other functions in ferrets. The highly conserved relative time course also has more general implications for the understanding of comparative aspects of development. In addition, the high reproducibility of data within the present study underscores the suitability of the ferret as an experimental animal for studies of motor development.
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