| 1. |
- Lundström, Johanna, et al.
(författare)
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Cost-effective age structure and geographical distribution of boreal forest reserves
- 2011
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Ingår i: Journal of Applied Ecology. - : Wiley. - 0021-8901 .- 1365-2664. ; 48, s. 133-142
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Tidskriftsartikel (refereegranskat)abstract
- P>1. Forest reserves are established to preserve biodiversity, and to maintain natural functions and processes. Today there is heightened focus on old-growth stages, with less attention given to early successional stages. The biodiversity potential of younger forests has been overlooked, and the cost-effectiveness of incorporating different age classes in reserve networks has not yet been studied.2. We performed a reserve selection analysis in boreal Sweden using the Swedish National Forest Inventory plots. Seventeen structural variables were used as biodiversity indicators, and the cost of protecting each plot as a reserve was assessed using the Heureka system. A goal programming approach was applied, which allowed inclusion of several objectives and avoided a situation in which common indicators affected the result more than rare ones. The model was limited either by budget or area.3. All biodiversity indicators were found in all age classes, with more than half having the highest values in ages >= 100 years. Several large-tree indicators and all deadwood indicators had higher values in forests 0-14 years than in forests 15-69 years.4. It was most cost-effective to protect a large proportion of young forests since they generally have a lower net present value compared to older forests, but still contain structures of importance for biodiversity. However, it was more area-effective to protect a large proportion of old forests since they have a higher biodiversity potential per area.5. The geographical distribution of reserves selected with the budget-constrained model was strongly biassed towards the north-western section of boreal Sweden, with a large proportion of young forest, whereas the area-constrained model focussed on the south-eastern section, with dominance by the oldest age class.6. Synthesis and applications. We show that young forests with large amounts of structures important to biodiversity such as dead wood and remnant trees are cheap and cost-efficient to protect. This suggests that reserve networks should incorporate sites with high habitat quality of different forest ages. Since young forests are generally neglected in conservation, our approach is of interest also to other forest biomes where biodiversity is adapted to disturbance regimes resulting in open, early successional stages.
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| 2. |
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| 3. |
- Ericsson, Emma, 1981-, et al.
(författare)
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Controlled Orientation and Covalent Attachment of Proteins on Biosensor Surfaces by Chelation Assisted Photoimmobilization
- 2013
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- This report presents a novel method for uniform orientation and covalent attachment of proteins to sensing surfaces, termed Chelation Assisted Photoimmobilization (CAP). Alkanethiols terminated with either nitrilotriacetic acid (NTA), benzophenone (BP) or oligo(ethylene glycol) were synthesized and mixed self-assembled monolayers (SAMs) were prepared on gold and thoroughly characterized by infrared reflection absorption spectroscopy (IRAS), ellipsometry and contact angle goniometry. In the process of CAP, NTA chelates Ni2+ and the complex coordinates a His-tagged ligand in an oriented assembly. The ligand is then photoimmobilized via BP, which forms covalent bonds upon UV light activation. The CAP concept was demonstrated using human IgG-Fc modified with C-terminal hexahistidine tags (His-IgGFc) as the ligand and protein A as the analyte.In the development of affinity biosensors, uniform orientation of ligand molecules where all analyte binding sites are accessible is often preferred to random orientation. In order to monitor the effect of ligand orientation on analyte response, the ligand-analyte interaction was quantified by surface plasmon resonance analysis, both in the case of CAP and when the ligand was attached by conventional amine coupling on surfaces presenting NTA. Responses were adjusted for differences in ligand immobilization level using IRAS. The normalized analyte response with randomly oriented ligand was 2.5 times higher than that with ligand immobilized by CAP, probably due to molecular crowding effects on the surface and the fact that His-IgGFc is bivalent for protein A. This is a reminder that many other factors than orientation alone may play a decisive role in analyte binding on biosensor surfaces.
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| 4. |
- Ericsson, Emma M, et al.
(författare)
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Controlled orientation and covalent attachment of proteins on biosensor surfaces by Chelation Assisted Photoimmobilization
- 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In the context of surface chemistry for affinity biosensor chips, it is widely accepted that uniform orientation of the immobilized recognition element (ligand) is preferred over random orientation. However, this assumption has often been based on studies where differences in ligand immobilization level have not been taken into account. In this contribution, we present a novel two-step method for homogenous orientation and covalent attachment of proteins to sensing surfaces, called Chelation Assisted Photoimmobilization (CAP). Careful quantification of the effect of ligand orientation on analyte responses was performed by comparing this strategy to immobilization by conventional amine coupling. In CAP, the chelation agent is nitrilotriacetic acid (NTA) which chelates Ni2+. A His-tagged ligand forms an oriented assembly when binding Ni2+-NTA and is then covalently bound to the surface via photolabile benzophenone (BP), which attacks C-H bonds upon UV light activation. We relied on a surface chemistry based on self-assembled monolayers (SAMs) of oligo(ethylene glycol) (OEG)-containing alkanethiolates on gold. Alkanethiols terminated with either NTA, BP or OEG were synthesized and mixed SAMs were characterized by infrared reflection absorption spectroscopy (IRAS), ellipsometry and contact angle goniometry. IRAS was also used to quantify ligand immobilization levels obtained either by CAP or by amine coupling via the carboxyl groups of an NTA-presenting surface. The model ligand was human IgG-Fc modified with a C-terminal 6xHis-tag and the analyte was Protein A. The ligand-analyte interaction was quantified by a surface plasmon resonance biosensor. Analyte responses were normalized with respect to the ligand amounts obtained by the two immobilization strategies. Interestingly, the normalized analyte response with randomly oriented ligand was >2 times higher than that with ligand immobilized by CAP. This shows that oriented ligand immobilization is not necessarily a means of increasing the sensitivity of a biosensor. Factors that may influence performance include the valency of the ligand and constraints related to the surface chemistry used for orientation.
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| 5. |
- Ericsson, Emma, et al.
(författare)
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Site-Specific and Covalent Attachment of His-Tagged Proteins by Chelation Assisted Photoimmobilization: A Strategy for Microarraying of Protein Ligands
- 2013
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Ingår i: Langmuir. - : American Chemical Society. - 0743-7463 .- 1520-5827. ; 29:37, s. 11687-11694
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Tidskriftsartikel (refereegranskat)abstract
- A novel strategy for site-specific and covalent attachment of proteins has been developed, intended for robust and controllable immobilization of histidine (His)-tagged ligands in protein microarrays. The method is termed chelation assisted photoimmobilization (CAP) and was demonstrated using human IgG-Fc modified with C-terminal hexahistidines (His-IgGFc) as the ligand and protein A as the analyte. Alkanethiols terminated with either nitrilotriacetic acid (NTA), benzophenone (BP); or oligo(ethylene glycol) were synthesized and mixed self-assembled monolayers (SAMs) were prepared on gold and thoroughly characterized by infrared reflection absorption spectroscopy (IRAS), ellipsometry, and contact angle goniometry. In the process of CAP, NTA chelates Ni2+ and the complex coordinates the His-tagged ligand in an oriented assembly. The ligand is then photoimmobilized via BP, which forms covalent bonds upon UV light activation. In the development of affinity biosensors and protein microarrays, site-specific attachment of ligands in a fashion where analyte binding sites are available is often preferred to random coupling. Analyte binding performance of ligands immobilized either by CAP or by standard amine coupling was characterized by surface plasmon resonance in combination with IRAS. The relative analyte response with randomly coupled ligand was 2.5 times higher than when site-specific attachment was used. This is a reminder that also when immobilizing ligands via residues far from the binding site, there are many other factors influencing availability and activity. Still, CAP provides a valuable expansion of protein immobilization techniques since it offers attractive microarraying possibilities amenable to applications within proteomics.
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| 6. |
- Jakobsson, Gunnar, et al.
(författare)
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Late dislocation of in-the-bag and out-of-the bag intraocular lenses: ocular and surgical characteristics and time to lens repositioning.
- 2010
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Ingår i: Journal of cataract and refractive surgery. - : Ovid Technologies (Wolters Kluwer Health). - 1873-4502 .- 0886-3350. ; 36:10, s. 1637-44
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To characterize patients with late intraocular lens (IOL) dislocation to evaluate possible risk factors, determine the time between cataract surgery and IOL repositioning, describe the surgical management, and estimate the incidence. SETTING: Department of Ophthalmology, Sahlgrenska University Hospital, Mölndal, Sweden. DESIGN: Case series. METHODS: Medical records from the cataract surgery and IOL repositioning were reviewed. RESULTS: The study enrolled 84 eyes, 63 with in-the-bag IOL dislocation and 21 with out-of-the-bag IOL dislocation. The prevalence of pseudoexfoliation (PXF) was 60% and of glaucoma, 36%. A high proportion of eyes with IOL dislocation (37%) had zonular dehiscence at cataract surgery. The median time from cataract surgery to IOL repositioning surgery was significantly shorter in eyes with out-of-the-bag IOL dislocation (3.2 years) than in eyes with in-the-bag IOL dislocation (6.7 years) (P = .029). The interval was also significantly shorter in eyes with zonular dehiscence. Using data from the National Cataract Register, the calculated incidence of IOL repositioning surgery per pseudophakic individuals in western Sweden was 0.050%. CONCLUSIONS: The possible major predisposing factors for late IOL dislocation were PXF, glaucoma, and cataract surgery complicated by zonular dehiscence. Primary placement of the IOL in the ciliary sulcus was associated with earlier IOL dislocation. Intraocular lens repositioning surgery using a posterior or anterior approach was successful in many cases. FINANCIAL
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| 7. |
- Ludvigsson, Johnny, et al.
(författare)
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GAD65 antigen therapy in recently diagnosed type 1 diabetes mellitus
- 2012
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Ingår i: New England Journal of Medicine. - : Massachusetts Medical Society. - 0028-4793 .- 1533-4406. ; 366:5, s. 433-442
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The 65-kD isoform of glutamic acid decarboxylase (GAD65) is a major autoantigen in type 1 diabetes. We hypothesized that alum-formulated GAD65 (GAD-alum) can preserve beta-cell function in patients with recent-onset type 1 diabetes.METHODS: We studied 334 patients, 10 to 20 years of age, with type 1 diabetes, fasting C-peptide levels of more than 0.3 ng per milliliter (0.1 nmol per liter), and detectable serum GAD65 autoantibodies. Within 3 months after diagnosis, patients were randomly assigned to receive one of three study treatments: four doses of GAD-alum, two doses of GAD-alum followed by two doses of placebo, or four doses of placebo. The primary outcome was the change in the stimulated serum C-peptide level (after a mixed-meal tolerance test) between the baseline visit and the 15-month visit. Secondary outcomes included the glycated hemoglobin level, mean daily insulin dose, rate of hypoglycemia, and fasting and maximum stimulated C-peptide levels.RESULTS: The stimulated C-peptide level declined to a similar degree in all study groups, and the primary outcome at 15 months did not differ significantly between the combined active-drug groups and the placebo group (P=0.10). The use of GAD-alum as compared with placebo did not affect the insulin dose, glycated hemoglobin level, or hypoglycemia rate. Adverse events were infrequent and mild in the three groups, with no significant differences.CONCLUSIONS: Treatment with GAD-alum did not significantly reduce the loss of stimulated C peptide or improve clinical outcomes over a 15-month period.
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| 8. |
- Lundström, Johanna, et al.
(författare)
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How reserve selection is affected by preferences in Swedish boreal forests
- 2014
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Ingår i: Forest Policy and Economics. - : Elsevier BV. - 1389-9341 .- 1872-7050. ; 41, s. 40-50
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Tidskriftsartikel (refereegranskat)abstract
- It is important to consider the preferences of the various stakeholders involved when evaluating effective reserve selection, since it is largely their preferences that determine which of a given set of potential reserve networks that actually is "the best". We interviewed eight conservation planners working at the county administrative boards in each of the eight administrative counties covering boreal Sweden to establish weightings for different structural biodiversity indicators by using the Analytic Hierarchy Process (AHP). The subjective weightings were applied in a reserve selection model based on a goal programming (GP) approach. The structural indicators were derived from the Swedish National Forest Inventory (NFI) and used as proxy for biodiversity potential. A biodiversity indicator score, based on the values of those indicators, was maximized. The model adjusted this score ensuring that all indicators were represented in the selection, and further also adjusted the influence of the indicators based on the subjective weightings. We evaluated the GP approach by comparing it to a simple linear programming (LP) formulation, only maximizing the indicator richness. In all cases the model was limited either by a budget or an area. The biodiversity potential in young forests are often neglected within present conservation policies, however, the proportion of selected forest under 15 years was relatively high in all our cost-effective cases, varying between 32% and 60% using the individual planners subjective weightings, compared to 80% when using a simple LP model. The proportion of selected forest over 100 years varied between 69% and 85% in the area-effective cases using the subjective weightings, compared to 80% when using a simple LP model. Middle-aged forest was not favored in any of the selections, although they make up a substantial part of the total area. We conclude that there are differences in how conservation planners prioritize the indicators, and depending on how specific biodiversity indicators are weighted the age distribution of the selected reserves differs. This demonstrates the importance of considering how to establish appropriate weightings. It is also important to consider the, at least in our case, substantial difference in how common the different indicators are to ensure that the weightings get their intended impact on the selections. (C) 2014 The Authors. Published by Elsevier B.V. All rights reserved.
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| 9. |
- Lundström, Johanna, et al.
(författare)
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Lichen species richness on retained aspens increases with time since clear-cutting
- 2013
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 293, s. 49-56
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Tidskriftsartikel (refereegranskat)abstract
- In modem forestry, attempts to mitigate negative effects on biodiversity include the integration of conservation actions into forestry activities, e.g. by leaving trees at harvesting. This practice has been used on a large scale for more than two decades without solid scientific support of whether desirable effects are achieved or not. To increase the knowledge of changes in the lichen flora on retained aspen trees (Populus tremula) with time since clear-cutting we made a study in boreal Sweden where 720 retained aspens in 24 stands were surveyed. Twelve stands were clear-felled 0-4 years and 12 where clear-felled 10-16 years prior to the inventory. Total lichen species richness increased with time since clear-cutting, as did richness of aspen-dependent lichens and lichens adapted to open environments. There was no difference between the age classes regarding the number of cyanolichens. We show that retained aspens function as lifeboats for old-forest lichens and as a new habitat for lichens adapted to open, sun-exposed habitats. Our results indicate that epiphytic species richness on retained trees is higher after the logging, due to coexistence of remaining species and colonizing species. We suggest that the retention of old aspen and the promotion of aspen generation in the production forest would benefit epiphytic lichens and are thus important conservation measures. (C) 2012 Elsevier B.V. All rights reserved.
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| 10. |
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