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Sökning: WFRF:(Grey T.)

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  • 2019
  • Tidskriftsartikel (refereegranskat)
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5.
  • Pantazis, N, et al. (författare)
  • Determining the likely place of HIV acquisition for migrants in Europe combining subject-specific information and biomarkers data
  • 2019
  • Ingår i: Statistical methods in medical research. - : SAGE Publications. - 1477-0334 .- 0962-2802. ; 28:7, s. 1979-1997
  • 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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  • Drake, Thomas M., et al. (författare)
  • Outcomes following small bowel obstruction due to malignancy in the national audit of small bowel obstruction
  • 2019
  • Ingår i: European Journal of Surgical Oncology. - : Elsevier BV. - 0748-7983 .- 1532-2157. ; 45:12, s. 2319-2324
  • Tidskriftsartikel (refereegranskat)abstract
    • © 2019 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology Introduction: Patients with cancer who develop small bowel obstruction are at high risk of malnutrition and morbidity following compromise of gastrointestinal tract continuity. This study aimed to characterise current management and outcomes following malignant small bowel obstruction. Methods: A prospective, multicentre cohort study of patients with small bowel obstruction who presented to UK hospitals between 16th January and 13th March 2017. Patients who presented with small bowel obstruction due to primary tumours of the intestine (excluding left-sided colonic tumours) or disseminated intra-abdominal malignancy were included. Outcomes included 30-day mortality and in-hospital complications. Cox-proportional hazards models were used to generate adjusted effects estimates, which are presented as hazard ratios (HR) alongside the corresponding 95% confidence interval (95% CI). The threshold for statistical significance was set at the level of P ≤ 0.05 a-priori. Results: 205 patients with malignant small bowel obstruction presented to emergency surgery services during the study period. Of these patients, 50 had obstruction due to right sided colon cancer, 143 due to disseminated intraabdominal malignancy, 10 had primary tumours of the small bowel and 2 patients had gastrointestinal stromal tumours. In total 100 out of 205 patients underwent a surgical intervention for obstruction. 30-day in-hospital mortality rate was 11.3% for those with primary tumours and 19.6% for those with disseminated malignancy. Severe risk of malnutrition was an independent predictor for poor mortality in this cohort (adjusted HR 16.18, 95% CI 1.86 to 140.84, p = 0.012). Patients with right-sided colon cancer had high rates of morbidity. Conclusions: Mortality rates were high in patients with disseminated malignancy and in those with right sided colon cancer. Further research should identify optimal management strategy to reduce morbidity for these patient groups.
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  • Ehlers, Anke, et al. (författare)
  • A randomised controlled trial of therapist-assisted online psychological therapies for posttraumatic stress disorder (STOP-PTSD) : trial protocol
  • 2020
  • Ingår i: Trials. - : BioMed Central. - 1745-6215. ; 21:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Over the last few decades, effective psychological treatments for posttraumatic stress disorder (PTSD) have been developed, but many patients are currently unable to access these treatments. There is initial evidence that therapist-assisted internet-based psychological treatments are effective for PTSD and may help increase access, but it remains unclear which of these treatments work best and are most acceptable to patients. This randomised controlled trial will compare a trauma-focussed and a nontrauma-focussed therapist-assisted cognitive behavioural Internet treatment for PTSD: Internet-delivered cognitive therapy for PTSD (iCT-PTSD) and internet-delivered stress management therapy (iStress-PTSD). Methods/design The study is a single-blind, randomised controlled trial comparing iCT-PTSD, iStress-PTSD and a 13-week wait-list condition, with an embedded process study. Assessors of treatment outcome will be blinded to trial arm. Two hundred and seventeen participants who meet DSM-5 criteria for PTSD will be randomly allocated by a computer programme to iCT-PTSD, iStress-PTSD or wait-list at a 3:3:1 ratio. The primary assessment point is at 13 weeks, and further assessments are taken at 6, 26, 39 and 65 weeks. The primary outcome measure is the severity of PTSD symptoms as measured by the PTSD Checklist for DSM-5 (PCL-5). Secondary measures of PTSD symptoms are the Clinician Administered PTSD Scale for DSM-5 (CAPS-5) and the Impact of Event Scale-Revised (IES-R). Other symptoms and well-being will be assessed with the Patient Health Questionnaire (PHQ-9), Generalised Anxiety Disorder Scale (GAD-7), WHO (Five) Well-Being Index, Work and Social Adjustment Scale (WSAS), Endicott Quality of Life Scale (QoL), and Insomnia Sleep Index (ISI). Health economics analyses will consider quality of life, productivity, health resource utilisation, employment status and state benefits, and treatment delivery costs. Process analyses will investigate candidate mediators and moderators of outcome. Patient experience will be assessed by interview and questionnaire. Discussion This study will be the first to compare the efficacy of a trauma-focussed and nontrauma-focussed therapist-assisted online cognitive behavioural treatment for people with posttraumatic stress disorder.
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11.
  • Ehlers, Anke, et al. (författare)
  • Therapist-assisted online psychological therapies differing in trauma focus for post-traumatic stress disorder (STOP-PTSD) : a UK-based, single-blind, randomised controlled trial
  • 2023
  • Ingår i: The lancet. Psychiatry. - : ELSEVIER SCI LTD. - 2215-0374 .- 2215-0366. ; 10:8, s. 608-622
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Many patients are currently unable to access psychological treatments for post-traumatic stress disorder (PTSD), and it is unclear which types of therapist-assisted internet-based treatments work best. We aimed to investigate whether a novel internet-delivered cognitive therapy for PTSD (iCT-PTSD), which implements all procedures of a first-line, trauma-focused intervention recommended by the UK National Institute for Health and Care Excellence (NICE) for PTSD, is superior to internet-delivered stress management therapy for PTSD (iStress-PTSD), a comprehensive cognitive behavioural treatment programme focusing on a wide range of coping skills.METHODS: We did a single-blind, randomised controlled trial in three locations in the UK. Participants (≥18 years) were recruited from UK National Health Service (NHS) Improving Access to Psychological Therapies (IAPT) services or by self-referral and met DSM-5 criteria for PTSD to single or multiple events. Participants were randomly allocated by a computer programme (3:3:1) to iCT-PTSD, iStress-PTSD, or a 3-month waiting list with usual NHS care, after which patients who still met PTSD criteria were randomly allocated (1:1) to iCT-PTSD or iStress-PTSD. Randomisation was stratified by location, duration of PTSD (<18 months or ≥18 months), and severity of PTSD symptoms (high vs low). iCT-PTSD and iStress-PTSD were delivered online with therapist support by messages and short weekly phone calls over the first 12 weeks (weekly treatment phase), and three phone calls over the next 3 months (booster phase). The primary outcome was the severity of PTSD symptoms at 13 weeks after random assignment, measured by self-report on the PTSD Checklist for DSM-5 (PCL-5), and analysed by intention-to-treat. Safety was assessed in all participants who started treatment. Process analyses investigated acceptability and compliance with treatment, and candidate moderators and mediators of outcome. The trial was prospectively registered with the ISRCTN registry, ISRCTN16806208.FINDINGS: Of the 217 participants, 158 (73%) self-reported as female, 57 (26%) as male, and two (1%) as other; 170 (78%) were White British, 20 (9%) were other White, six (3%) were Asian, ten (5%) were Black, eight (4%) had a mixed ethnic background, and three (1%) had other ethnic backgrounds. Mean age was 36·36 years (SD 12·11; range 18-71 years). 52 (24%) participants met self-reported criteria for ICD-11 complex PTSD. Fewer than 10% of participants dropped out of each treatment group. iCT-PTSD was superior to iStress-PTSD in reducing PTSD symptoms, showing an adjusted difference on the PCL-5 of -4·92 (95% CI -8·92 to -0·92; p=0·016; standardised effect size d=0·38 [0·07 to 0·69]) for immediate allocations and -5·82 (-9·59 to -2·04; p=0·0027; d=0·44 [0·15 to 0·72]) for all treatment allocations. Both treatments were superior to the waiting list for PCL-5 at 13 weeks (d=1·67 [1·23 to 2·10] for iCT-PTSD and 1·29 [0·85 to 1·72] for iStress-PTSD). The advantages in outcome for iCT-PTSD were greater for participants with high dissociation or complex PTSD symptoms, and mediation analyses showed both treatments worked by changing negative meanings of the trauma, unhelpful coping, and flashback memories. No serious adverse events were reported.INTERPRETATION: Trauma-focused iCT-PTSD is effective and acceptable to patients with PTSD, and superior to a non-trauma-focused cognitive behavioural stress management therapy, suggesting that iCT-PTSD is an effective way of delivering the contents of CT-PTSD, one of the NICE-recommended first-line treatments for PTSD, while reducing therapist time compared with face-to-face therapy.FUNDING: Wellcome Trust, UK National Institute for Health and Care Research Oxford Health Biomedical Research Centre.
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12.
  • Gustafson, Grey T., et al. (författare)
  • The morphology and behavior of the endemic Malagasy whirligig beetle Heterogyrus milloti Legros, 1953 (Coleoptera: Gyrinidae: Heterogyrinae)
  • 2017
  • Ingår i: The Coleopterists bulletin. - 0010-065X .- 1938-4394. ; 71:2, s. 315-328
  • Tidskriftsartikel (refereegranskat)abstract
    • The Malagasy endemic whirligig beetle Heterogyrus milloti Legros, 1953 is redescribed. Jumping behavior of H. milloti is reported here for the first time with video recordings provided. Results of a behavioral experiment conducted in the field demonstrate H. milloti jumps in a targeted manner in a downstream direction. The unique habitat of H. milloti is described in detail with both image and video of the habitat included. Morphology of H. milloti is discussed in detail, revealing symplesiomorphies with Spanglerogyrus Folkerts, 1979, characters forming transitional series between Spanglerogyrus and the Gyrininae, and features unique to H. milloti. The potential adaptive significance of these peculiar morphological features in association with the habitat of H. milloti is discussed. Finally, an argument for the necessity of conservation of this species is made, and common names in English, French, Malagasy, and Swedish for H. milloti are proposed to aid conservation efforts.
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  • Gustafson, Grey T., et al. (författare)
  • Tip-dated phylogeny of whirligig beetles reveals ancient lineage surviving on Madagascar
  • 2017
  • Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7, s. 1-9
  • Tidskriftsartikel (refereegranskat)abstract
    • The temporal origin of Madagascar’s extraordinary endemic diversity is debated. A preference for Cenozoic dispersal origins has replaced the classical view of Mesozoic vicariance in the wake of molecular dating. However, evidence of ancient origins is mounting from arthropod groups. Using phylogenetic ‘tip-dating’ analysis with fossils, we show that a whirligig beetle species, Heterogyrus milloti, inhabiting forest streams in southeastern Madagascar is the last survivor of a once dominant and widespread Mesozoic group. With a Late Triassic to Early Jurassic origin (226–187 Ma) it is the hitherto oldest dated endemic lineage of animal or plant on Madagascar. Island biotas’ sensitivity to extinction is well known, but islands can also provide refuge from continental extinction. Heterogyrus milloti is an irreplaceable link to the freshwater biota of the Mesozoic and serves as a reminder of what may be lost without critical conservation e orts on Madagascar. 
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14.
  • Michat, Mariano (författare)
  • Larval description and chaetotaxic analysis of Dineutus sinuosipennis Laporte, 1840, with a key for the identification of larvae of the tribe Dineutini (Coleoptera, Gyrinidae).
  • 2017
  • Ingår i: ZooKeys. - : Pensoft Publishers. - 1313-2989 .- 1313-2970. ; 718, s. 95-114
  • Tidskriftsartikel (refereegranskat)abstract
    •  The larvae of the Malagasy whirligig beetle Dineutus sinuosipennis Laporte, 1840, identified using DNA sequence data, are described and illustrated for the first time, including detailed morphometric and chaetotaxic analyses of selected structures and a description of larval habitat. Larvae of the genus Dineutus Macleay, 1825 are diagnosed, and a key to identify the genera of the tribe Dineutini is presented. Larvae of Dineutus exhibit the characters traditionally recognized as autapomorphies of the Gyrinidae: body less sclerotized, egg bursters located on the parietal, one additional sensorial plate on the third antennomere, cardo and lacinia well developed, prementum completely divided, abdominal tracheal gills, and four terminal hooks on the pygopod. They also share with larvae of the other Dineutini genera these putative synapomorphies: numerous minute pore-like additional structures on the ultimate maxillary and labial palpomeres, coxal primary seta CO12 inserted submedially, and trochanteral primary seta TR2 absent. Larvae of Dineutus can be distinguished from those of other known genera of Dineutini by the posterior margin of the lacinia not dentate, tracheal gills plumose, parietal seta PA5 inserted relatively far from setae PA7–9, mandibular pores MNb and MNc inserted relatively far from each other, and tarsal seta TA1 inserted submedially.
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  • Monroe, J. Grey, et al. (författare)
  • Mutation bias reflects natural selection in Arabidopsis thaliana
  • 2022
  • Ingår i: Nature. - : Springer Nature. - 0028-0836 .- 1476-4687. ; 602:7895, s. 101-105
  • Tidskriftsartikel (refereegranskat)abstract
    • Since the first half of the twentieth century, evolutionary theory has been dominated by the idea that mutations occur randomly with respect to their consequences(1). Here we test this assumption with large surveys of de novo mutations in the plant Arabidopsis thaliana. In contrast to expectations, we find that mutations occur less often in functionally constrained regions of the genome-mutation frequency is reduced by half inside gene bodies and by two-thirds in essential genes. With independent genomic mutation datasets, including from the largest Arabidopsis mutation accumulation experiment conducted to date, we demonstrate that epigenomic and physical features explain over 90% of variance in the genome-wide pattern of mutation bias surrounding genes. Observed mutation frequencies around genes in turn accurately predict patterns of genetic polymorphisms in natural Arabidopsis accessions (r = 0.96). That mutation bias is the primary force behind patterns of sequence evolution around genes in natural accessions is supported by analyses of allele frequencies. Finally, we find that genes subject to stronger purifying selection have a lower mutation rate. We conclude that epigenome-associated mutation bias2 reduces the occurrence of deleterious mutations in Arabidopsis, challenging the prevailing paradigm that mutation is a directionless force in evolution.
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  • Myo Min, Kay K, et al. (författare)
  • Desmoglein-2 is important for islet function and β-cell survival
  • 2022
  • Ingår i: Cell Death & Disease. - : Springer Science and Business Media LLC. - 2041-4889. ; 13:10
  • Tidskriftsartikel (refereegranskat)abstract
    • Type 1 diabetes is a complex disease characterized by the lack of endogenous insulin secreted from the pancreatic β-cells. Although β-cell targeted autoimmune processes and β-cell dysfunction are known to occur in type 1 diabetes, a complete understanding of the cell-to-cell interactions that support pancreatic function is still lacking. To characterize the pancreatic endocrine compartment, we studied pancreata from healthy adult donors and investigated a single cell surface adhesion molecule, desmoglein-2 (DSG2). Genetically-modified mice lacking Dsg2 were examined for islet cell mass, insulin production, responses to glucose, susceptibility to a streptozotocin-induced mouse model of hyperglycaemia, and ability to cure diabetes in a syngeneic transplantation model. Herein, we have identified DSG2 as a previously unrecognized adhesion molecule that supports β-cells. Furthermore, we reveal that DSG2 is within the top 10 percent of all genes expressed by human pancreatic islets and is expressed by the insulin-producing β-cells but not the somatostatin-producing δ-cells. In a Dsg2 loss-of-function mice (Dsg2lo/lo), we observed a significant reduction in the number of pancreatic islets and islet size, and consequently, there was less total insulin content per islet cluster. Dsg2lo/lo mice also exhibited a reduction in blood vessel barrier integrity, an increased incidence of streptozotocin-induced diabetes, and islets isolated from Dsg2lo/lo mice were more susceptible to cytokine-induced β-cell apoptosis. Following transplantation into diabetic mice, islets isolated from Dsg2lo/lo mice were less effective than their wildtype counterparts at curing diabetes. In vitro assays using the Beta-TC-6 murine β-cell line suggest that DSG2 supports the actin cytoskeleton as well as the release of cytokines and chemokines. Taken together, our study suggests that DSG2 is an under-appreciated regulator of β-cell function in pancreatic islets and that a better understanding of this adhesion molecule may provide new opportunities to combat type 1 diabetes.
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18.
  • Ngo, Ngoc T.N., et al. (författare)
  • Efficient laccase/TEMPO oxidation of alkyl glycosides : Effects of carbohydrate group and alkyl chain length
  • 2020
  • Ingår i: Journal of Biotechnology: X. - : Elsevier BV. - 2590-1559 .- 0168-1656. ; 8
  • Tidskriftsartikel (refereegranskat)abstract
    • Alkyl glycosides with long hydrophobic chains have attractive surfactant properties, but their wider application is hampered by their low solubility in water. Here, a route to increased solubility by introduction of carboxyl groups via laccase/TEMPO oxidation is presented. The oxidation pathways for dodecyl β-maltoside and hexadecyl β-maltoside were studied in detail. Close to full conversion was achieved for both substrates and conditions were found under which the diacid products dominated, with only minor amounts of under-oxidized and over-oxidized products. Dodecyl β-maltoside oxidation was improved to give a yield of 85 % of the diacid derivative. Interestingly, in spite of low substrate solubility the oxidation of hexadecyl β-maltoside was very efficient in aqueous medium, due to the higher solubility of the products. Addition of organic cosolvents did not provide additional advantages. The method is promising for producing soluble anionic derivatives of alkyl glycosides in an environmentally friendly and efficient way.
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19.
  • Ngo, Ngoc T. N., et al. (författare)
  • Synthesis of novel oligomeric anionic alkyl glycosides using laccase/TEMPO oxidation and cyclodextrin glucanotransferase (CGTase)‐catalysed transglycosylation
  • 2021
  • Ingår i: Biotechnology and Bioengineering. - : Wiley. - 1097-0290 .- 0006-3592. ; 118:7, s. 2548-2558
  • Tidskriftsartikel (refereegranskat)abstract
    • Modification of alkyl glycosides, to alter their properties and widen the scope of potential applications, is of considerable interest. Here, we report the synthesis of new anionic alkyl glycosides with long carbohydrate chains, using two different approaches: laccase/TEMPO oxidation of a long‐carbohydrate‐chain alkyl glycoside, and cyclodextrin glucanotransferase (CGTase)‐catalysed elongation of anionic alkyl glycosides. The laccase/TEMPO oxidation of dodecyl β‐D‐maltooctaoside proceeded efficiently with the formation of aldehyde and acid products. However, depolymerization occurred to a large extent, limiting the product yield and purity. On the other hand, CGTase‐catalysed coupling/disproportionation reactions with α‐cyclodextrin and dodecyl β‐D‐maltoside diuronic acid (DDM‐2COOH) or octyl β‐D‐glucuronic acid (OG‐COOH) as substrates gave high conversions, especially when the CGTase Toruzyme was used. It was found that pH had a strong influence on both the enzyme activity and the acceptor specificity. With non‐ionic substrates (dodecyl β‐D‐maltoside and octyl β‐D‐glucoside), Toruzyme exhibited high catalytic activity at pH 5‐6, but for the acidic substrates (DDM‐2COOH and OG‐COOH) the activity was highest at pH 4. This is most likely due to the enzyme favoring the protonated forms of DDM‐2COOH and OG‐COOH, which exist at lower pH (pKa about 3).
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20.
  • Price, Nicholas, et al. (författare)
  • Combining population genomics and fitness QTLs to identify the genetics of local adaptation in Arabidopsis thaliana
  • 2018
  • Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : NATL ACAD SCIENCES. - 0027-8424 .- 1091-6490. ; 115:19, s. 5028-5033
  • Tidskriftsartikel (refereegranskat)abstract
    • Evidence for adaptation to different climates in the model species Arabidopsis thaliana is seen in reciprocal transplant experiments, but the genetic basis of this adaptation remains poorly understood. Field-based quantitative trait locus (QTL) studies provide direct but low-resolution evidence for the genetic basis of local adaptation. Using high-resolution population genomic approaches, we examine local adaptation along previously identified genetic trade-off (GT) and conditionally neutral (CN) QTLs for fitness between locally adapted Italian and Swedish A. thaliana populations [angstrom gren J, et al. (2013) Proc Natl Acad Sci USA 110: 21077-21082]. We find that genomic regions enriched in high F-ST SNPs colocalize with GT QTL peaks. Many of these high F-ST regions also colocalize with regions enriched for SNPs significantly correlated to climate in Eurasia and evidence of recent selective sweeps in Sweden. Examining unfolded site frequency spectra across genes containing high F-ST SNPs suggests GTs may be due to more recent adaptation in Sweden than Italy. Finally, we collapse a list of thousands of genes spanning GT QTLs to 42 genes that likely underlie the observed GTs and explore potential biological processes driving these trade-offs, from protein phosphorylation, to seed dormancy and longevity. Our analyses link population genomic analyses and field-based QTL studies of local adaptation, and emphasize that GTs play an important role in the process of local adaptation.
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21.
  • Reeder, Brandon J, et al. (författare)
  • Tyrosine residues as redox cofactors in human hemoglobin : implications for engineering nontoxic blood substitutes
  • 2008
  • Ingår i: Journal of Biological Chemistry. - 0021-9258. ; 283:45, s. 30780-30787
  • Tidskriftsartikel (refereegranskat)abstract
    • Respiratory proteins such as myoglobin and hemoglobin can, under oxidative conditions, form ferryl heme iron and protein-based free radicals. Ferryl myoglobin can safely be returned to the ferric oxidation state by electron donation from exogenous reductants via a mechanism that involves two distinct pathways. In addition to direct transfer between the electron donor and ferryl heme edge, there is a second pathway that involves "through-protein" electron transfer via a tyrosine residue (tyrosine 103, sperm whale myoglobin). Here we show that the heterogeneous subunits of human hemoglobin, the alpha and beta chains, display significantly different kinetics for ferryl reduction by exogenous reductants. By using selected hemoglobin mutants, we show that the alpha chain possesses two electron transfer pathways, similar to myoglobin. Furthermore, tyrosine 42 is shown to be a critical component of the high affinity, through-protein electron transfer pathway. We also show that the beta chain of hemoglobin, lacking the homologous tyrosine, does not possess this through-protein electron transfer pathway. However, such a pathway can be engineered into the protein by mutation of a specific phenylalanine residue to a tyrosine. High affinity through-protein electron transfer pathways, whether native or engineered, enhance the kinetics of ferryl removal by reductants, particularly at low reductant concentrations. Ferryl iron has been suggested to be a major cause of the oxidative toxicity of hemoglobin-based blood substitutes. Engineering hemoglobin with enhanced rates of ferryl removal, as we show here, is therefore likely to result in molecules better suited for in vivo oxygen delivery.
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22.
  • Tanentzap, Andrew J., et al. (författare)
  • Terrestrial support of lake food webs : Synthesis reveals controls over cross-ecosystem resource use
  • 2017
  • Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 3:3
  • Tidskriftsartikel (refereegranskat)abstract
    • Widespread evidence that organic matter exported from terrestrial into aquatic ecosystems supports recipient food webs remains controversial. A pressing question is not only whether high terrestrial support is possible but also what the general conditions are under which it arises. We assemble the largest data set, to date, of the isotopic composition (delta H-2, delta C-13, and delta N-15) of lake zooplankton and the resources at the base of their associated food webs. In total, our data set spans 559 observations across 147 lakes from the boreal to subtropics. By predicting terrestrial resource support from within-lake and catchment-level characteristics, we found that half of all consumer observations that is, the median were composed of at least 42% terrestrially derived material. In general, terrestrial support of zooplankton was greatest in lakes with large physical and hydrological connections to catchments that were rich in aboveground and belowground organic matter. However, some consumers responded less strongly to terrestrial resources where within-lake production was elevated. Our study shows that multiple mechanisms drive widespread cross-ecosystem support of aquatic consumers across Northern Hemisphere lakes and suggests that changes in terrestrial landscapes will influence ecosystem processes well beyond their boundaries.
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23.
  • Tapia-Ruiz, Nuria, et al. (författare)
  • 2021 roadmap for sodium-ion batteries
  • 2021
  • Ingår i: Journal of Physics. - : Institute of Physics Publishing (IOPP). - 2515-7655. ; 3:3
  • Tidskriftsartikel (refereegranskat)abstract
    • Increasing concerns regarding the sustainability of lithium sources, due to their limited availability and consequent expected price increase, have raised awareness of the importance of developing alternative energy-storage candidates that can sustain the ever-growing energy demand. Furthermore, limitations on the availability of the transition metals used in the manufacturing of cathode materials, together with questionable mining practices, are driving development towards more sustainable elements. Given the uniformly high abundance and cost-effectiveness of sodium, as well as its very suitable redox potential (close to that of lithium), sodium-ion battery technology offers tremendous potential to be a counterpart to lithium-ion batteries (LIBs) in different application scenarios, such as stationary energy storage and low-cost vehicles. This potential is reflected by the major investments that are being made by industry in a wide variety of markets and in diverse material combinations. Despite the associated advantages of being a drop-in replacement for LIBs, there are remarkable differences in the physicochemical properties between sodium and lithium that give rise to different behaviours, for example, different coordination preferences in compounds, desolvation energies, or solubility of the solid-electrolyte interphase inorganic salt components. This demands a more detailed study of the underlying physical and chemical processes occurring in sodium-ion batteries and allows great scope for groundbreaking advances in the field, from lab-scale to scale-up. This roadmap provides an extensive review by experts in academia and industry of the current state of the art in 2021 and the different research directions and strategies currently underway to improve the performance of sodium-ion batteries. The aim is to provide an opinion with respect to the current challenges and opportunities, from the fundamental properties to the practical applications of this technology.
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