Swedish University of Agricultural Sciences

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    16577 research outputs found

    Withdrawal periods after treatment of pigs with oxytetracycline in- and outside the European Union

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    Withdrawal periods are used to avoid animals being delivered to slaughter before the concentration of the antimicrobial has declined to values below the maximum residue limit (MRL). This paper characterises the withdrawal periods in force for oxytetracycline 100 mg/ml for intramuscular use in pigs. We investigated the variation in duration of the withdrawal period between 68 oxytetracycline products from 29 countries in- and outside the European Union. More specifically, we tested whether there is a regional difference, a difference between major and minor pig meat exporting countries, whether the product is long-acting or not, and whether year of market authorisation correlated with the withdrawal period. The results showed a large variation in duration of the withdrawal periods, ranging from 5 to 40 days. Variation was observed both between and within countries. Moreover, major exporting countries were associated with a longer withdrawal period than minor exporting countries (P = 0.00099). There were no regional differences, and the year of market authorisation had no impact, but long-acting products had a shorter withdrawal period than short-acting products (P = 0.048). The variation in withdrawal periods observed questions the utility of using compliance with the withdrawal period as a means of assessing whether the meat is safe for consumption. This is particularly relevant when a pig producer unintentionally delivers pigs for slaughter before the withdrawal period has expired and, aware of this, informs the abattoir. The findings call for further harmonisation in determining the withdrawal periods for all veterinary medicinal products (VMP). Until this happens, if animals are prematurely sent to slaughter, we suggest that the concentration of the VMP at the time of slaughter is calculated and compared with the MRL to determine meat safety

    Future climate impacts of sodium-ion batteries

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    Sodium-ion batteries (SIBs) have emerged as an alternative to lithium-ion batteries (LIBs) due to their promising performance in terms of battery cycle lifetime, safety, operating in wider temperature range, as well as the abundant and low-cost of sodium resources. This study evaluated the climate impacts of three SIBs, and compared to two LIBs under four scenarios with considering potential changes in battery performance and background productions between 2020 and 2050. To ensure a fair comparison, all batteries were modeled in the 21,700 form, and a battery dimensioning model was developed to calculate the required amount of components for each battery. We found that equal to lower GHG emissions result from the use of SIBs compared to LIBs under optimal performance scenarios. From 2020 to 2050, the climate impacts of SIBs decreased by 43-57 %. The relative contribution of the battery manufacturing process decreases from 18-32 % to 2-4 % due to the increasingly share of clean energy in the electricity grid, while the relative contribution of key battery component materials increases over time, especially for cathode active materials. These results emphasize the significance of decarbonizing the electric grid, and suggest that future investment in SIBs is promising from an environmental point of view

    Quantitative and qualitative saccharide analysis of North Atlantic brown seaweed by gas chromatography/mass spectrometry and infrared spectroscopy

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    Brown seaweeds contain a variety of saccharides which have potential industrial uses. The most abundant polysaccharide in brown seaweed is typically alginate, consisting of mannuronic (M) and guluronic acid (G). The ratio of these residues fundamentally determines the physicochemical properties of alginate. In the present study, gas chromatography/mass spectrometry (GC/MS) was used to give a detailed breakdown of the monosaccharide species in North Atlantic brown seaweeds. The anthrone method was used for determination of crystalline cellulose. The experimental data was used to calibrate multivariate prediction models for estimation of total carbohydrates, crystalline cellulose, total alginate and alginate M/G ratio directly in dried, brown seaweed using three types of infrared spectroscopy, using relative error (RE) as a measure of predictive accuracy. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) performed well for the estimation of total alginate (RE = 0.12, R2 = 0.82), and attenuated total reflectance (ATR) showed good prediction of M/G ratio (RE = 0.14, R2 = 0.86). Both DRIFTS, ATR and near infrared (NIR) were unable to predict crystalline cellulose and only DRIFTS performed better in determining total carbohydrates. Multivariate spectral analysis is a promising method for easy and rapid characterization of alginate and M/G ratio in seaweed

    Immobilizing arsenic in contaminated anoxic aquifer sediment using sulfidated and uncoated zero-valent iron (ZVI)

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    Arsenic (As) is carcinogenic and of major concern in groundwater. We collected sediment material from a contaminated anoxic aquifer in Sweden and investigated the immobilization of As by four commercial zero-valent iron (ZVI) particles. Solid-phase As and Fe speciation was assessed using X-ray absorption spectroscopy (XAS) and solution-phase As speciation using chromatographic separation. Without ZVI addition, arsenite dominated in solution and As(V) species in the solid phase. Adding ZVI caused a sharp increase in solution pH (9.3-9.8), favoring As oxidation despite a lowered redox potential. ZVI greatly improved As retention by complex binding of arsenate to the Fe(III) (hydr)oxides formed by ZVI corrosion. Uncoated ZVI, both in nano-and microscale, performed better than their sulfidated counterparts, partly due to occlusion of As by the Fe(III) (hydr) oxides formed. The effect of particle size (micro vs. nano ZVI) on As immobilization was small, likely because immobilization was related to the corrosion products formed, rather than the initial size of the particles. Our results provide a strong geochemical background for the application of ZVI particles to remove As in contaminated aquifers under anoxic conditions and illustrate that immobilization mechanisms can differ between ZVI in As spiked solutions and sediment suspensions.Environmental implication: Arsenic ranks first on the list by the US ATSDR of substances posing a threat to human health and the WHO considers groundwater the riskiest source for human intake of As. However, dealing with As contamination remains a scientific challenge. We studied the immobilization of groundwater As by commercially available ZVI particles at field-realistic conditions. Arsenic immobilization was highly efficient in most cases, and the results suggest this is a promising in situ strategy with long-term performance. Our results provide a strong geochemical background for using ZVI to remove As in contaminated anoxic aquifers

    Fungal Communities Associated with Siricid Wood Wasps: Focus on Sirex juvencus, Urocerus gigas, and Tremex fuscicornis

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    We investigated the diversity and occurrence of wood wasps in Lithuania and determined communities of associated fungi. Trapping of wood wasps resulted in three different species, including Sirex juvencus, Urocerus gigas, and Tremex fuscicornis. Fungal culturing from adult females of T. fuscicornis mainly resulted in fungi from the genera Penicillium and Trichoderma. High-throughput sequencing of ITS2 rDNA resulted in 59,797 high-quality fungal sequences, representing 127 fungal OTUs. There were 93 fungal OTUs detected in U. gigas, 66 in S. juvencus, and 10 in T. fuscicornis. The most common fungi were Fusarium sporotrichioides (63.1% of all fungal sequences), Amylostereum chailletii (14.9%), Penicillium crustosum (7.8%), Microascus sp. 2261_4 (5.0%), and Pithoascus ater (2.1%). Among these, only A. chailletii was found in all three insect species with the highest relative abundance in U. gigas (15.2%), followed by S. juvencus (7.7%), and the lowest in T. fuscicornis (0.3%) (

    Soil structure and water functions in agricultural soils of the temperate-boreal zone in a changing climate

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    Climate change may affect the productivity of cropping systems in the temperateboreal zone by increasing the frequency of periods with water excess and shortage. Soils have the capacity to buffer such extreme weather events by regulating water storage and fluxes, which are mainly a function of soil structure. However, climate itself is linked to the evolution of soil structure through a multitude of processes (e.g., freezing and thawing, soil management). The main objective of this thesis was to improve our understanding of the effects of climate-driven processes on the porespace structure of agricultural soils in order to identify potential implications for soil water functions in the context of climate change. This was done using a wide range of approaches including a meta-analysis, a laboratory experiment, and the application of machine learning to a newly developed index of soil structure based on relative entropy. It was revealed that climate is an important driver of the structural pore space of arable soils in Sweden and Norway. Warmer and wetter regions showed a less developed structure compared to cooler and drier regions, in particular in the subsoil, although it remains unclear whether this was the result of direct or indirect climate-driven processes. With climate change, the number and intensity of freeze-thaw cycles is expected to increase in some parts of the temperateboreal zone. Results from this thesis show that this may lead to increased drainage rates in compacted soil layers under near-saturated conditions as well as improved pore connectivity, especially in fine-textured soils. Furthermore, most changes in pore-space structure induced by freezing and thawing were found for pores of diameter

    Comparison between IAD and other maturity indices in nine commercially grown apple cultivars

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    To maintain storage potential as long as possible, it is important to harvest fruit at optimal maturity. Different maturity indices have been developed, including flesh firmness, soluble solids content, starch degradation, ethylene production, and respiration rate. However, many of them are destructive, time consuming, and may be require some laboratory equipment to perform. The portable device DA-meter (measuring index of absorption difference; IAD) can monitor the chlorophyll decline non-destructively in the field, and could potentially save time. To evaluate the IAD in comparison with other maturity indices, nine common commercial cultivars of apple were investigated in a three-year trial. Correlations between IAD and other maturity indices, especially starch degradation and ripening index by Streif were strong in most cultivars, though variation between years lead to weaker correlations were found last year of the trial. The strongest correlations were found between IAD and harvest date showing that IAD decreased with time in all investigated cultivars. Comparison between IAD and ripening index by Streif showed in some cases that the two indices decreased at the same time, suggesting that IAD could be used to monitor maturity when it is rapid. The suitability to use IAD as a maturity index seems to be cultivar-dependent. For cultivars having a more consistent pattern between years in the decrease of IAD, combined with relatively low variation in IAD at any given time, it could be a good complement to other commonly used maturity indices

    Does Keeping Cows for More Lactations Affect the Composition and Technological Properties of the Milk?

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    Simple Summary Swedish dairy cows have an average life expectancy of 5 years, i.e., approximately 2.5 lactations during their lifespan. Increasing cow longevity is associated with better animal welfare and lower greenhouse gases per unit milk and cow. However, it is important that there are no negative effects on milk quality if cows are retained in production for longer periods. This study investigated the composition and technological properties of milk from older (>= 3 lactations) and young (1-2 lactations) cows. Apart from higher plasmin and lower plasminogen-derived activity in older cows, the results indicated no major differences in milk quality between the parity groups.Abstract This study investigated differences in the raw milk composition and technological properties between cows with different numbers of lactations. In total, 12 commercial herds were visited within a period of 12 weeks. On each farm, milk samples from five young cows (lactations 1-2) and five older cows (lactation >= 3) were collected. For each farm, milk samples from the young cows and the older cows, respectively, were pooled. The pooled milk samples were analyzed for gross composition and technological properties. Using principal component analysis (PCA) to assess the overall variation in milk quality attributes and the potential clustering of milk from young cows and older cows, respectively, an effect of breed, but no clear effect of lactation number, was observed. In contrast, one-way ANOVA showed higher plasmin activity (p = 0.002) in pooled milk from the older cows, whereas plasminogen-derived activity (p = 0.001) and total proteolysis (p = 0.029) were higher in milk from the young cows. Likewise, orthogonal projections to latent structure discriminant analysis (OPLS-DA) showed higher plasmin activity in milk from older cows, whereas younger cows had higher plasminogen-related activity and higher total proteolysis. To conclude, except for plasmin and plasminogen-related activities, there were no major differences in the composition and technological properties between milk from older cows and young cows

    Cultures of Human Skin Mast Cells, an Attractive In Vitro Model for Studies of Human Mast Cell Biology

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    Studies of mast cell biology are dependent on relevant and validated in vitro models. Here, we present detailed information concerning the phenotype of both freshly isolated human skin mast cells (MCs) and of in vitro cultures of these cells that were obtained by analyzing their total transcriptome. Transcript levels of MC-related granule proteins and transcription factors were found to be remarkably stable over a 3-week culture period. Relatively modest changes were also seen for important cell surface receptors including the high-affinity receptor for IgE, FCER1A, the low-affinity receptor for IgG, FCGR2A, and the receptor for stem cell factor, KIT. FCGR2A was the only Fc receptor for IgG expressed by these cells. The IgE receptor increased by 2-5-fold and an approximately 10-fold reduction in the expression of FCGR2A was observed most likely due to the cytokines, SCF and IL-4, used for expanding the cells. Comparisons of the present transcriptome against previously reported transcriptomes of mouse peritoneal MCs and mouse bone marrow-derived MCs (BMMCs) revealed both similarities and major differences. Strikingly, cathepsin G was the most highly expressed granule protease in human skin MCs, in contrast to the almost total absence of this protease in both mouse MCs. Transcript levels for the majority of cell surface receptors were also very low compared to the granule proteases in both mouse and human MCs, with a difference of almost two orders of magnitude. An almost total absence of T-cell granzymes was observed in human skin MCs, indicating that granzymes have no or only a minor role in human MC biology. Ex vivo skin MCs expressed high levels of selective immediate early genes and transcripts of heat shock proteins. In validation experiments, we determined that this expression was an inherent property of the cells and not the result of the isolation process. Three to four weeks in culture results in an induction of cell growth-related genes accompanying their expansion by 6-10-fold, which increases the number of cells for in vitro experiments. Collectively, we show that cultured human skin MCs resemble their ex vivo equivalents in many respects and are a more relevant in vitro model compared to mouse BMMCs for studies of MC biology, in particular human MC biology

    Drivers and resilience of methane-derived carbon contribution to chironomid biomass in boreal lakes

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    General mechanisms underlying the pathways of methane (CH4)-derived carbon in aquatic food webs are often associated with eutrophication-driven anoxia. Yet, the influence of changing nutrient availability on CH4 cycling has been mainly investigated during the increasing phase (i.e. onset of anthropogenic eutrophication), thus leaving unclear whether nutrient reduction can lead to a simple reversion of the observed effects on CH4 cycling. We combined stable isotopes of chironomid remains (delta 13CHC) and sedimentary ancient DNA of methanotrophic bacteria (MOB) to unravel the drivers of biogenic CH4 contribution to chironomid biomass in boreal lakes. Using a spatial dataset, our study shows that delta 13CHC values were more depleted in hypoxic lakes and were positively associated with methanotrophic bacteria belonging to the gamma-proteobacteria class (MOB type I), therefore supporting the view of higher utilization of CH4-derived carbon in anoxic environments. However, this space-for-time substitution approach failed to provide any reliable information on whether lake food webs follow the same pathway in forward and reverse directions. Using downcore reconstruction, our results show that despite a drastic mitigation-induced decrease in nutrient concentrations and strong evidence of biological recovery of algal and chironomid communities, chironomid biomass remained highly subsidized by methanotrophic bacteria throughout the study period. Results therefore suggest that mechanisms underlying the pathways of CH4-derived carbon in aquatic food webs are likely not the same during perturbation and recovery trajectories and that complex feedback mechanisms can stabilize lakes in this CH4-based food web state


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