Nikolaj Rasmussen | Adler Graduate School (original) (raw)

Uploads

Papers by Nikolaj Rasmussen

Journal of Molecular Biology, 2008

The crystal structure of the first immunoglobulin (Ig1) domain of neural cell adhesion molecule 2... more The crystal structure of the first immunoglobulin (Ig1) domain of neural cell adhesion molecule 2 (NCAM2/OCAM/RNCAM) is presented at a resolution of 2.7 Å. NCAM2 is a member of the immunoglobulin superfamily of cell adhesion molecules (IgCAMs). In the structure, two Ig domains interact by domain swapping, as the two N-terminal β-strands are interchanged. β-Strand swapping at the terminal domain is the accepted mechanism of homophilic interactions amongst the cadherins, another class of CAMs, but it has not been observed within the IgCAM superfamily. Gel-filtration chromatography demonstrated the ability of NCAM2 Ig1 to form dimers in solution. Taken together, these observations suggest that β-strand swapping could have a role in the molecular mechanism of homophilic binding for NCAM2.

Journal of Hospital Infection, 2011

Objective: To compare 1-year potencies' of heparin-bonded PTFE [(Hb-PTFE) (Propaten Ò )] grafts w... more Objective: To compare 1-year potencies' of heparin-bonded PTFE [(Hb-PTFE) (Propaten Ò )] grafts with those of ordinary polytetraflouroethylene (PTFE) grafts in a blinded, randomised, clinically controlled, multi-centre study. Materials and methods: Eleven Scandinavian centres enrolled 569 patients with chronic functional or critical lower limb ischaemia who were scheduled to undergo femoroefemoral bypass or femoroepoplitaeal bypass. The patients were randomised 1:1 stratified by centre. Patency was assessed by duplex ultrasound scanning. A total of 546 patients (96%) completed the study with adequate follow-up.

Water Resources Research, 2008

1] A new model of phytotoxicity of salt and plant salt uptake is presented and is coupled to an e... more 1] A new model of phytotoxicity of salt and plant salt uptake is presented and is coupled to an existing three-dimensional groundwater simulation model. The implementation of phytotoxicity and salt uptake relationships is based on experimental findings from willow trees grown in hydroponic solution. The data confirm an s-shaped phytotoxicity relationship as found in previous studies. Uptake data were explained assuming steady state salt concentration in plant roots, passive salt transport into the roots, and active enzymatic removal of salt from plant roots. On the one hand, transpiration strongly depends on groundwater salinity (phytotoxicity); on the other hand, transpiration significantly changes the groundwater salinity (uptake). This feedback loop generates interesting dynamic phenomena in hydrological systems that are dominated by transpiration and are influenced by significant salinity gradients. Generic simulations are performed for the Okavango island system and are shown to reproduce essential phenomena observed in nature. Citation: Bauer-Gottwein, P., N. F. Rasmussen, D. Feificova, and S. Trapp (2008), Phytotoxicity of salt and plant salt uptake: Modeling ecohydrological feedback mechanisms, Water Resour. Res., 44, W04418,

Polymer Engineering and Science, 2006

Well-defined nano-topographies were prepared by electron-beam lithography and electroplated to fo... more Well-defined nano-topographies were prepared by electron-beam lithography and electroplated to form nickel-shims. The surface pattern consisted of square pillars repeated equidistantly within the plane of the surface in a perpendicular arrangement. The width and distance between the squares both ranged from 310 to 3100 nm. All the pillars were 220 nm high. The nickel-shim was used as a surface-template during injection molding of polycarbonate. Secondly, a nickel shim, with a surface pattern consisted of a squared sine with a period of 700 nm and amplitude of 450 nm, was mounted on, and it was in good thermal contact with the upper plate in a hot-press. Polycarbonate/polystyrene was melted on the lower plate while the temperature of the shim was kept below the glass transition temperature. The upper plate was lowered until the shim was in contact with the melt. Experiments were carried out with a clean shim and a shim coated with a monolayer of fluorocarbonsilane. As a result of the surface coating, the amplitude of the replicated grating decreased from about 350 nm in polycarbonate and 100 nm in polystyrene to less than 10 nm. The experiments strongly suggest that the possibility to injection mold sub-micrometer surface structures in polymers mainly relates to adhesive energy between polymer and shim. POLYM. ENG. SCI. 46:160–171, 2006. © 2005 Society of Plastics Engineers

International Journal of Hygiene and Environmental Health, 2010

Multiple chemical sensitivity (MCS) is characterised by adverse effects due to exposure to low le... more Multiple chemical sensitivity (MCS) is characterised by adverse effects due to exposure to low levels of chemical substances. Various genes, especially genes of importance to the metabolism of xenobiotic compounds, have been associated with MCS, but findings are inconsistent. The purpose of this study was to investigate genetic susceptibility factors for MCS and self-reported chemical sensitivity in a population sample. Ninety six MCS patients and 1,207 controls from a general population divided into four severity groups of chemical sensitivity were genotyped for variants in the genes encoding cytochrome P450 2D6, arylamine N-acetyltransferase 2, paraoxonase 1, methylene tetrahydrofolate reductase, and the cholecystokinin 2 receptor. No hypotheses were consistently confirmed. An apparent association between number of active cytochrome P450 2D6 alleles and MCS status was not statistically significant (OR= 1.2, p =0.28). Fast arylamine N-acetyltransferase 2 metaboliser status was associated with severity of chemical sensitivity only in the most severely affected group in the population sample (OR = 3.1, p =0.04). The cholecystokinin 2 receptor allele with 21 CT repeats was associated with MCS when compared in post hoc analyses with all individuals from the population sample (p =0.02). Genetic variants in paraoxonase 1 and methylene tetrahydrofolate reductase were not associated with MSC or with self-reported chemical sensitivity in the population sample. Our results suggest that variants in the genes examined are of less importance to MCS than previously reported or that gene-environment interactions or significant degrees of genetic heterogeneity in MCS underlie inconsistent findings in the literature.

Journal of Development Effectiveness, 2011

Recent advances in the use of randomised control trials to evaluate the effect of development int... more Recent advances in the use of randomised control trials to evaluate the effect of development interventions promise to enhance our knowledge of what works and why. A core argument supporting randomised studies is the claim that they have high internal validity. The authors argue that this claim is weak as long as a trial registry of development interventions is not in place. Without a trial registry, the possibilities for data mining, created by analyses of multiple outcomes and subgroups, undermine internal validity. Drawing on experience from evidence-based medicine and recent examples from microfinance, they argue that a trial registry would also enhance external validity and foster innovative research.

Journal of Molecular Biology, 2008

The crystal structure of the first immunoglobulin (Ig1) domain of neural cell adhesion molecule 2... more The crystal structure of the first immunoglobulin (Ig1) domain of neural cell adhesion molecule 2 (NCAM2/OCAM/RNCAM) is presented at a resolution of 2.7 Å. NCAM2 is a member of the immunoglobulin superfamily of cell adhesion molecules (IgCAMs). In the structure, two Ig domains interact by domain swapping, as the two N-terminal β-strands are interchanged. β-Strand swapping at the terminal domain is the accepted mechanism of homophilic interactions amongst the cadherins, another class of CAMs, but it has not been observed within the IgCAM superfamily. Gel-filtration chromatography demonstrated the ability of NCAM2 Ig1 to form dimers in solution. Taken together, these observations suggest that β-strand swapping could have a role in the molecular mechanism of homophilic binding for NCAM2.

Journal of Hospital Infection, 2011

Objective: To compare 1-year potencies' of heparin-bonded PTFE [(Hb-PTFE) (Propaten Ò )] grafts w... more Objective: To compare 1-year potencies' of heparin-bonded PTFE [(Hb-PTFE) (Propaten Ò )] grafts with those of ordinary polytetraflouroethylene (PTFE) grafts in a blinded, randomised, clinically controlled, multi-centre study. Materials and methods: Eleven Scandinavian centres enrolled 569 patients with chronic functional or critical lower limb ischaemia who were scheduled to undergo femoroefemoral bypass or femoroepoplitaeal bypass. The patients were randomised 1:1 stratified by centre. Patency was assessed by duplex ultrasound scanning. A total of 546 patients (96%) completed the study with adequate follow-up.

Water Resources Research, 2008

1] A new model of phytotoxicity of salt and plant salt uptake is presented and is coupled to an e... more 1] A new model of phytotoxicity of salt and plant salt uptake is presented and is coupled to an existing three-dimensional groundwater simulation model. The implementation of phytotoxicity and salt uptake relationships is based on experimental findings from willow trees grown in hydroponic solution. The data confirm an s-shaped phytotoxicity relationship as found in previous studies. Uptake data were explained assuming steady state salt concentration in plant roots, passive salt transport into the roots, and active enzymatic removal of salt from plant roots. On the one hand, transpiration strongly depends on groundwater salinity (phytotoxicity); on the other hand, transpiration significantly changes the groundwater salinity (uptake). This feedback loop generates interesting dynamic phenomena in hydrological systems that are dominated by transpiration and are influenced by significant salinity gradients. Generic simulations are performed for the Okavango island system and are shown to reproduce essential phenomena observed in nature. Citation: Bauer-Gottwein, P., N. F. Rasmussen, D. Feificova, and S. Trapp (2008), Phytotoxicity of salt and plant salt uptake: Modeling ecohydrological feedback mechanisms, Water Resour. Res., 44, W04418,

Polymer Engineering and Science, 2006

Well-defined nano-topographies were prepared by electron-beam lithography and electroplated to fo... more Well-defined nano-topographies were prepared by electron-beam lithography and electroplated to form nickel-shims. The surface pattern consisted of square pillars repeated equidistantly within the plane of the surface in a perpendicular arrangement. The width and distance between the squares both ranged from 310 to 3100 nm. All the pillars were 220 nm high. The nickel-shim was used as a surface-template during injection molding of polycarbonate. Secondly, a nickel shim, with a surface pattern consisted of a squared sine with a period of 700 nm and amplitude of 450 nm, was mounted on, and it was in good thermal contact with the upper plate in a hot-press. Polycarbonate/polystyrene was melted on the lower plate while the temperature of the shim was kept below the glass transition temperature. The upper plate was lowered until the shim was in contact with the melt. Experiments were carried out with a clean shim and a shim coated with a monolayer of fluorocarbonsilane. As a result of the surface coating, the amplitude of the replicated grating decreased from about 350 nm in polycarbonate and 100 nm in polystyrene to less than 10 nm. The experiments strongly suggest that the possibility to injection mold sub-micrometer surface structures in polymers mainly relates to adhesive energy between polymer and shim. POLYM. ENG. SCI. 46:160–171, 2006. © 2005 Society of Plastics Engineers

International Journal of Hygiene and Environmental Health, 2010

Multiple chemical sensitivity (MCS) is characterised by adverse effects due to exposure to low le... more Multiple chemical sensitivity (MCS) is characterised by adverse effects due to exposure to low levels of chemical substances. Various genes, especially genes of importance to the metabolism of xenobiotic compounds, have been associated with MCS, but findings are inconsistent. The purpose of this study was to investigate genetic susceptibility factors for MCS and self-reported chemical sensitivity in a population sample. Ninety six MCS patients and 1,207 controls from a general population divided into four severity groups of chemical sensitivity were genotyped for variants in the genes encoding cytochrome P450 2D6, arylamine N-acetyltransferase 2, paraoxonase 1, methylene tetrahydrofolate reductase, and the cholecystokinin 2 receptor. No hypotheses were consistently confirmed. An apparent association between number of active cytochrome P450 2D6 alleles and MCS status was not statistically significant (OR= 1.2, p =0.28). Fast arylamine N-acetyltransferase 2 metaboliser status was associated with severity of chemical sensitivity only in the most severely affected group in the population sample (OR = 3.1, p =0.04). The cholecystokinin 2 receptor allele with 21 CT repeats was associated with MCS when compared in post hoc analyses with all individuals from the population sample (p =0.02). Genetic variants in paraoxonase 1 and methylene tetrahydrofolate reductase were not associated with MSC or with self-reported chemical sensitivity in the population sample. Our results suggest that variants in the genes examined are of less importance to MCS than previously reported or that gene-environment interactions or significant degrees of genetic heterogeneity in MCS underlie inconsistent findings in the literature.

Journal of Development Effectiveness, 2011

Recent advances in the use of randomised control trials to evaluate the effect of development int... more Recent advances in the use of randomised control trials to evaluate the effect of development interventions promise to enhance our knowledge of what works and why. A core argument supporting randomised studies is the claim that they have high internal validity. The authors argue that this claim is weak as long as a trial registry of development interventions is not in place. Without a trial registry, the possibilities for data mining, created by analyses of multiple outcomes and subgroups, undermine internal validity. Drawing on experience from evidence-based medicine and recent examples from microfinance, they argue that a trial registry would also enhance external validity and foster innovative research.