| 1. |
- Pantazis, N, et al.
(författare)
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Determining the likely place of HIV acquisition for migrants in Europe combining subject-specific information and biomarkers data
- 2019
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Ingår i: Statistical methods in medical research. - : SAGE Publications. - 1477-0334 .- 0962-2802. ; 28:7, s. 1979-1997
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Tidskriftsartikel (refereegranskat)abstract
- In most HIV-positive individuals, infection time is only known to lie between the time an individual started being at risk for HIV and diagnosis time. However, a more accurate estimate of infection time is very important in certain cases. For example, one of the objectives of the Advancing Migrant Access to Health Services in Europe (aMASE) study was to determine if HIV-positive migrants, diagnosed in Europe, were infected pre- or post-migration. We propose a method to derive subject-specific estimates of unknown infection times using information from HIV biomarkers’ measurements, demographic, clinical, and behavioral data. We assume that CD4 cell count (CD4) and HIV-RNA viral load trends after HIV infection follow a bivariate linear mixed model. Using post-diagnosis CD4 and viral load measurements and applying the Bayes’ rule, we derived the posterior distribution of the HIV infection time, whereas the prior distribution was informed by AIDS status at diagnosis and behavioral data. Parameters of the CD4–viral load and time-to-AIDS models were estimated using data from a large study of individuals with known HIV infection times (CASCADE). Simulations showed substantial predictive ability (e.g. 84% of the infections were correctly classified as pre- or post-migration). Application to the aMASE study ( n = 2009) showed that 47% of African migrants and 67% to 72% of migrants from other regions were most likely infected post-migration. Applying a Bayesian method based on bivariate modeling of CD4 and viral load, and subject-specific information, we found that the majority of HIV-positive migrants in aMASE were most likely infected after their migration to Europe.
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| 2. |
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| 3. |
- Bento, Celeste, et al.
(författare)
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Genetic Basis of Congenital Erythrocytosis : Mutation Update and Online Databases
- 2014
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Ingår i: Human Mutation. - : Wiley-Blackwell. - 1059-7794 .- 1098-1004. ; 35:1, s. 15-26
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Tidskriftsartikel (refereegranskat)abstract
- Congenital erythrocytosis (CE), or congenital polycythemia, represents a rare and heterogeneous clinical entity. It is caused by deregulated red blood cell production where erythrocyte overproduction results in elevated hemoglobin and hematocrit levels. Primary congenital familial erythrocytosis is associated with low erythropoietin (Epo) levels and results from mutations in the Epo receptor gene (EPOR). Secondary CE arises from conditions causing tissue hypoxia and results in increased Epo production. These include hemoglobin variants with increased affinity for oxygen (HBB, HBA mutations), decreased production of 2,3-bisphosphoglycerate due to BPGM mutations, or mutations in the genes involved in the hypoxia sensing pathway (VHL, EPAS1, and EGLN1). Depending on the affected gene, CE can be inherited either in an autosomal dominant or recessive mode, with sporadic cases arising de novo. Despite recent important discoveries in the molecular pathogenesis of CE, the molecular causes remain to be identified in about 70% of the patients. With the objective of collecting all the published and unpublished cases of CE the COST action MPN&MPNr-Euronet developed a comprehensive Internet-based database focusing on the registration of clinical history, hematological, biochemical, and molecular data (http://www.erythrocytosis.org/). In addition, unreported mutations are also curated in the corresponding Leiden Open Variation Database.
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| 4. |
- da Cruz Francisco, José, et al.
(författare)
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A Comparative Study of Gelatinization of Cassava and Potato Starch in an Aqueous Lipid Phase (L2) Compared to Water
- 1996
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Ingår i: Food Hydrocolloids. - 0268-005X. ; 10:3, s. 317-322
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Tidskriftsartikel (refereegranskat)abstract
- The competition for water between an aqueous lipid phase (L2) and gelatinizing starch was investigated. Differential scanning calorimetry and light microscopy, were used to study the gelatinization behaviour of cassava and potato starch in the thermodynamically stable water containing (i.e. 13% w/w water) oil-continuous L2-phase. This was compared to the gelatinization of the two starches in limited and excess water (i.e. 56 and 77% w/w eater). The heating of 10.0% w/w cassava and potato starch in the L2-phase resulted in a 20 degrees shift upwards in temperature for the onset temperature and the temperature of peak maximum of the starch gelatinization compared with the starch-water samples with limited or excess water. Results from the microscopy, study showed that heating a gradually increasing amount of starch in the L2-phase shifts the gelatinization interval to increasingly higher temperatures. The enthalpy of gelatinization was reduced with >50% when the 10.0% w/w cassava and potato starch were gelatinized in the L2-phase. This is due to that part of the water is associated to the lipids in the L2-phase in such a way that it is not available for the starch. X-ray diffraction examinations of the cassava starch showed that the diffraction pattern was of the A-type. When the water content was increased the pattern changed towards the C-type.
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| 5. |
- Malhi, Yadvinder, et al.
(författare)
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The linkages between photosynthesis, productivity, growth and biomass in lowland Amazonian forests
- 2015
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013. ; 21:6, s. 2283-2295
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the relationship between photosynthesis, net primary productivity and growth in forest ecosystems is key to understanding how these ecosystems will respond to global anthropogenic change, yet the linkages among these components are rarely explored in detail. We provide the first comprehensive description of the productivity, respiration and carbon allocation of contrasting lowland Amazonian forests spanning gradients in seasonal water deficit and soil fertility. Using the largest data set assembled to date, ten sites in three countries all studied with a standardized methodology, we find that (i) gross primary productivity (GPP) has a simple relationship with seasonal water deficit, but that (ii) site-to-site variations in GPP have little power in explaining site-to-site spatial variations in net primary productivity (NPP) or growth because of concomitant changes in carbon use efficiency (CUE), and conversely, the woody growth rate of a tropical forest is a very poor proxy for its productivity. Moreover, (iii) spatial patterns of biomass are much more driven by patterns of residence times (i.e. tree mortality rates) than by spatial variation in productivity or tree growth. Current theory and models of tropical forest carbon cycling under projected scenarios of global atmospheric change can benefit from advancing beyond a focus on GPP. By improving our understanding of poorly understood processes such as CUE, NPP allocation and biomass turnover times, we can provide more complete and mechanistic approaches to linking climate and tropical forest carbon cycling.
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