| 1. |
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| 2. |
- Wang, H. D., et al.
(författare)
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Global, regional, and national under-5 mortality, adult mortality, age-specific mortality, and life expectancy, 1970-2016: a systematic analysis for the Global Burden of Disease Study 2016
- 2017
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Ingår i: Lancet. - 0140-6736 .- 1474-547X. ; 390:10100, s. 1084-1150
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Tidskriftsartikel (refereegranskat)abstract
- Background Detailed assessments of mortality patterns, particularly age-specific mortality, represent a crucial input that enables health systems to target interventions to specific populations. Understanding how all-cause mortality has changed with respect to development status can identify exemplars for best practice. To accomplish this, the Global Burden of Diseases, Injuries, and Risk Factors Study 2016 (GBD 2016) estimated age-specific and sex-specific all-cause mortality between 1970 and 2016 for 195 countries and territories and at the subnational level for the five countries with a population greater than 200 million in 2016. Methods We have evaluated how well civil registration systems captured deaths using a set of demographic methods called death distribution methods for adults and from consideration of survey and census data for children younger than 5 years. We generated an overall assessment of completeness of registration of deaths by dividing registered deaths in each location-year by our estimate of all-age deaths generated from our overall estimation process. For 163 locations, including subnational units in countries with a population greater than 200 million with complete vital registration (VR) systems, our estimates were largely driven by the observed data, with corrections for small fluctuations in numbers and estimation for recent years where there were lags in data reporting (lags were variable by location, generally between 1 year and 6 years). For other locations, we took advantage of different data sources available to measure under-5 mortality rates (U5MR) using complete birth histories, summary birth histories, and incomplete VR with adjustments; we measured adult mortality rate (the probability of death in individuals aged 15-60 years) using adjusted incomplete VR, sibling histories, and household death recall. We used the U5MR and adult mortality rate, together with crude death rate due to HIV in the GBD model life table system, to estimate age-specific and sex-specific death rates for each location-year. Using various international databases, we identified fatal discontinuities, which we defined as increases in the death rate of more than one death per million, resulting from conflict and terrorism, natural disasters, major transport or technological accidents, and a subset of epidemic infectious diseases; these were added to estimates in the relevant years. In 47 countries with an identified peak adult prevalence for HIV/AIDS of more than 0.5% and where VR systems were less than 65% complete, we informed our estimates of age-sex-specific mortality using the Estimation and Projection Package (EPP)-Spectrum model fitted to national HIV/AIDS prevalence surveys and antenatal clinic serosurveillance systems. We estimated stillbirths, early neonatal, late neonatal, and childhood mortality using both survey and VR data in spatiotemporal Gaussian process regression models. We estimated abridged life tables for all location-years using age-specific death rates. We grouped locations into development quintiles based on the Sociodemographic Index (SDI) and analysed mortality trends by quintile. Using spline regression, we estimated the expected mortality rate for each age-sex group as a function of SDI. We identified countries with higher life expectancy than expected by comparing observed life expectancy to anticipated life expectancy on the basis of development status alone. Findings Completeness in the registration of deaths increased from 28% in 1970 to a peak of 45% in 2013; completeness was lower after 2013 because of lags in reporting. Total deaths in children younger than 5 years decreased from 1970 to 2016, and slower decreases occurred at ages 5-24 years. By contrast, numbers of adult deaths increased in each 5-year age bracket above the age of 25 years. The distribution of annualised rates of change in age-specific mortality rate differed over the period 2000 to 2016 compared with earlier decades: increasing annualised rates of change were less frequent, although rising annualised rates of change still occurred in some locations, particularly for adolescent and younger adult age groups. Rates of stillbirths and under-5 mortality both decreased globally from 1970. Evidence for global convergence of death rates was mixed; although the absolute difference between age-standardised death rates narrowed between countries at the lowest and highest levels of SDI, the ratio of these death rates-a measure of relative inequality-increased slightly. There was a strong shift between 1970 and 2016 toward higher life expectancy, most noticeably at higher levels of SDI. Among countries with populations greater than 1 million in 2016, life expectancy at birth was highest for women in Japan, at 86.9 years (95% UI 86.7-87.2), and for men in Singapore, at 81.3 years (78.8-83.7) in 2016. Male life expectancy was generally lower than female life expectancy between 1970 and 2016, and the gap between male and female life expectancy increased with progression to higher levels of SDI. Some countries with exceptional health performance in 1990 in terms of the difference in observed to expected life expectancy at birth had slower progress on the same measure in 2016. Interpretation Globally, mortality rates have decreased across all age groups over the past five decades, with the largest improvements occurring among children younger than 5 years. However, at the national level, considerable heterogeneity remains in terms of both level and rate of changes in age-specific mortality; increases in mortality for certain age groups occurred in some locations. We found evidence that the absolute gap between countries in age-specific death rates has declined, although the relative gap for some age-sex groups increased. Countries that now lead in terms of having higher observed life expectancy than that expected on the basis of development alone, or locations that have either increased this advantage or rapidly decreased the deficit from expected levels, could provide insight into the means to accelerate progress in nations where progress has stalled. Copyright (C) The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.
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| 3. |
- Hay, S. I., et al.
(författare)
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Global, regional, and national disability-adjusted life-years (DALYs) for 333 diseases and injuries and healthy life expectancy (HALE) for 195 countries and territories, 1990-2016 : A systematic analysis for the Global Burden of Disease Study 2016
- 2017
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Ingår i: The Lancet. - : Lancet Publishing Group. - 0140-6736 .- 1474-547X. ; 390:10100, s. 1260-1344
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Tidskriftsartikel (refereegranskat)abstract
- Background: Measurement of changes in health across locations is useful to compare and contrast changing epidemiological patterns against health system performance and identify specific needs for resource allocation in research, policy development, and programme decision making. Using the Global Burden of Diseases, Injuries, and Risk Factors Study 2016, we drew from two widely used summary measures to monitor such changes in population health: disability-adjusted life-years (DALYs) and healthy life expectancy (HALE). We used these measures to track trends and benchmark progress compared with expected trends on the basis of the Socio-demographic Index (SDI). Methods: We used results from the Global Burden of Diseases, Injuries, and Risk Factors Study 2016 for all-cause mortality, cause-specific mortality, and non-fatal disease burden to derive HALE and DALYs by sex for 195 countries and territories from 1990 to 2016. We calculated DALYs by summing years of life lost and years of life lived with disability for each location, age group, sex, and year. We estimated HALE using age-specific death rates and years of life lived with disability per capita. We explored how DALYs and HALE difered from expected trends when compared with the SDI: the geometric mean of income per person, educational attainment in the population older than age 15 years, and total fertility rate. Findings: The highest globally observed HALE at birth for both women and men was in Singapore, at 75·2 years (95% uncertainty interval 71·9-78·6) for females and 72·0 years (68·8-75·1) for males. The lowest for females was in the Central African Republic (45·6 years [42·0-49·5]) and for males was in Lesotho (41·5 years [39·0-44·0]). From 1990 to 2016, global HALE increased by an average of 6·24 years (5·97-6·48) for both sexes combined. Global HALE increased by 6·04 years (5·74-6·27) for males and 6·49 years (6·08-6·77) for females, whereas HALE at age 65 years increased by 1·78 years (1·61-1·93) for males and 1·96 years (1·69-2·13) for females. Total global DALYs remained largely unchanged from 1990 to 2016 (-2·3% [-5·9 to 0·9]), with decreases in communicable, maternal, neonatal, and nutritional (CMNN) disease DALYs ofset by increased DALYs due to non-communicable diseases (NCDs). The exemplars, calculated as the fve lowest ratios of observed to expected age-standardised DALY rates in 2016, were Nicaragua, Costa Rica, the Maldives, Peru, and Israel. The leading three causes of DALYs globally were ischaemic heart disease, cerebrovascular disease, and lower respiratory infections, comprising 16·1% of all DALYs. Total DALYs and age-standardised DALY rates due to most CMNN causes decreased from 1990 to 2016. Conversely, the total DALY burden rose for most NCDs; however, age-standardised DALY rates due to NCDs declined globally. Interpretation: At a global level, DALYs and HALE continue to show improvements. At the same time, we observe that many populations are facing growing functional health loss. Rising SDI was associated with increases in cumulative years of life lived with disability and decreases in CMNN DALYs ofset by increased NCD DALYs. Relative compression of morbidity highlights the importance of continued health interventions, which has changed in most locations in pace with the gross domestic product per person, education, and family planning. The analysis of DALYs and HALE and their relationship to SDI represents a robust framework with which to benchmark location-specific health performance. Country-specific drivers of disease burden, particularly for causes with higher-than-expected DALYs, should inform health policies, health system improvement initiatives, targeted prevention eforts, and development assistance for health, including fnancial and research investments for all countries, regardless of their level of sociodemographic development. The presence of countries that substantially outperform others suggests the need for increased scrutiny for proven examples of best practices, which can help to extend gains, whereas the presence of underperforming countries suggests the need for devotion of extra attention to health systems that need more robust support. © The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.
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| 4. |
- Abbafati, Cristiana, et al.
(författare)
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- 2020
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Tidskriftsartikel (refereegranskat)
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| 5. |
- Feigin, Valery L., et al.
(författare)
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Global, regional, and national burden of stroke and its risk factors, 1990-2019 : a systematic analysis for the Global Burden of Disease Study 2019
- 2021
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Ingår i: Lancet Neurology. - : Elsevier. - 1474-4422 .- 1474-4465. ; 20:10, s. 795-820
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Tidskriftsartikel (refereegranskat)abstract
- Background Regularly updated data on stroke and its pathological types, including data on their incidence, prevalence, mortality, disability, risk factors, and epidemiological trends, are important for evidence-based stroke care planning and resource allocation. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) aims to provide a standardised and comprehensive measurement of these metrics at global, regional, and national levels. Methods We applied GBD 2019 analytical tools to calculate stroke incidence, prevalence, mortality, disability-adjusted life-years (DALYs), and the population attributable fraction (PAF) of DALYs (with corresponding 95% uncertainty intervals [UIs]) associated with 19 risk factors, for 204 countries and territories from 1990 to 2019. These estimates were provided for ischaemic stroke, intracerebral haemorrhage, subarachnoid haemorrhage, and all strokes combined, and stratified by sex, age group, and World Bank country income level. Findings In 2019, there were 12.2 million (95% UI 11.0-13.6) incident cases of stroke, 101 million (93.2-111) prevalent cases of stroke, 143 million (133-153) DALYs due to stroke, and 6.55 million (6.00-7.02) deaths from stroke. Globally, stroke remained the second-leading cause of death (11.6% [10.8-12.2] of total deaths) and the third-leading cause of death and disability combined (5.7% [5.1-6.2] of total DALYs) in 2019. From 1990 to 2019, the absolute number of incident strokes increased by 70.0% (67.0-73.0), prevalent strokes increased by 85.0% (83.0-88.0), deaths from stroke increased by 43.0% (31.0-55.0), and DALYs due to stroke increased by 32.0% (22.0-42.0). During the same period, age-standardised rates of stroke incidence decreased by 17.0% (15.0-18.0), mortality decreased by 36.0% (31.0-42.0), prevalence decreased by 6.0% (5.0-7.0), and DALYs decreased by 36.0% (31.0-42.0). However, among people younger than 70 years, prevalence rates increased by 22.0% (21.0-24.0) and incidence rates increased by 15.0% (12.0-18.0). In 2019, the age-standardised stroke-related mortality rate was 3.6 (3.5-3.8) times higher in the World Bank low-income group than in the World Bank high-income group, and the age-standardised stroke-related DALY rate was 3.7 (3.5-3.9) times higher in the low-income group than the high-income group. Ischaemic stroke constituted 62.4% of all incident strokes in 2019 (7.63 million [6.57-8.96]), while intracerebral haemorrhage constituted 27.9% (3.41 million [2.97-3.91]) and subarachnoid haemorrhage constituted 9.7% (1.18 million [1.01-1.39]). In 2019, the five leading risk factors for stroke were high systolic blood pressure (contributing to 79.6 million [67.7-90.8] DALYs or 55.5% [48.2-62.0] of total stroke DALYs), high body-mass index (34.9 million [22.3-48.6] DALYs or 24.3% [15.7-33.2]), high fasting plasma glucose (28.9 million [19.8-41.5] DALYs or 20.2% [13.8-29.1]), ambient particulate matter pollution (28.7 million [23.4-33.4] DALYs or 20.1% [16.6-23.0]), and smoking (25.3 million [22.6-28.2] DALYs or 17.6% [16.4-19.0]). Interpretation The annual number of strokes and deaths due to stroke increased substantially from 1990 to 2019, despite substantial reductions in age-standardised rates, particularly among people older than 70 years. The highest age-standardised stroke-related mortality and DALY rates were in the World Bank low-income group. The fastest-growing risk factor for stroke between 1990 and 2019 was high body-mass index. Without urgent implementation of effective primary prevention strategies, the stroke burden will probably continue to grow across the world, particularly in low-income countries.
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| 6. |
- Lakens, Daniel, et al.
(författare)
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Justify your alpha
- 2018
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Ingår i: Nature Human Behaviour. - : Nature Publishing Group. - 2397-3374. ; 2:3, s. 168-171
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Tidskriftsartikel (refereegranskat)abstract
- In response to recommendations to redefine statistical significance to P ≤ 0.005, we propose that researchers should transparently report and justify all choices they make when designing a study, including the alpha level.
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| 7. |
- Farnocchia, Davide, et al.
(författare)
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International Asteroid Warning Network Timing Campaign: 2019 XS
- 2022
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Ingår i: The Planetary Science Journal. - : Institute of Physics Publishing (IOPP). - 2632-3338. ; 3:7
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Tidskriftsartikel (refereegranskat)abstract
- As part of the International Asteroid Warning Network's observational exercises, we conducted a campaign to observe near-Earth asteroid 2019 XS around its close approach to Earth on 2021 November 9. The goal of the campaign was to characterize errors in the observation times reported to the Minor Planet Center, which become an increasingly important consideration as astrometric accuracy improves and more fast-moving asteroids are observed. As part of the exercise, a total of 957 astrometric observations of 2019 XS during the encounter were reported and subsequently were analyzed to obtain the corresponding residuals. While the timing errors are typically smaller than 1 s, the reported times appear to be negatively biased, i.e., they are generally earlier than they should be. We also compared the observer-provided position uncertainty with the cross-track residuals, which are independent of timing errors. A large fraction of the estimated uncertainties appear to be optimistic, especially when <0 2. We compiled individual reports for each observer to help identify and remove the root cause of any possible timing error and improve the uncertainty quantification process. We suggest possible sources of timing errors and describe a simple procedure to derive reliable, conservative position uncertainties.
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| 8. |
- Caretta, Martina Angela, et al.
(författare)
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Water
- 2022
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Ingår i: Climate Change 2022: Impacts, Adaptation and Vulnerability : Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change - Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change.
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 9. |
- Farnocchia, Davide, et al.
(författare)
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The Second International Asteroid Warning Network Timing Campaign: 2005 LW3
- 2023
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Ingår i: The Planetary Science Journal. - : Institute of Physics (IOP). - 2632-3338. ; 4:11
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Tidskriftsartikel (refereegranskat)abstract
- The Earth close approach of near-Earth asteroid 2005 LW3 on 2022 November 23 represented a good opportunity for a second observing campaign to test the timing accuracy of astrometric observation. With 82 participating stations, the International Asteroid Warning Network collected 1046 observations of 2005 LW3 around the time of the close approach. Compared to the previous timing campaign targeting 2019 XS, some individual observers were able to significantly improve the accuracy of their reported observation times. In particular, U.S. surveys achieved good timing performance. However, no broad, systematic improvement was achieved compared to the previous campaign, with an overall negative bias persisting among the different observers. The calibration of observing times and the mitigation of timing errors should be important future considerations for observers and orbit computers, respectively.
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| 10. |
- Nizam, P. A., et al.
(författare)
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Mechanically Robust Antibacterial Nanopapers Through Mixed Dimensional Assembly for Anionic Dye Removal
- 2020
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Ingår i: Journal of Polymers and the Environment. - : Springer Science and Business Media LLC. - 1572-8919 .- 1566-2543. ; 28:4, s. 1279-1291
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Tidskriftsartikel (refereegranskat)abstract
- There is a piqued interest in development of biobased sorbents for water treatment. Here in we reported, the fabrication of mechanically strong nanopapers by mixed dimensional assembly of 1D Cellulose nanofibers and 2D amino functionalized graphene oxide for water treatment. The fabricated amino functionalized GO/ cellulose nanofiber (AMGO-CNF) nanopaper showed superior antibacterial resistance towards Escherichia coli MTCC 1610 and Klebsiella due to the enhanced surface roughness which was confirmed from SEM and AFM studies. The amino group present in the AMGO enhanced the adsorption efficiency of the nanopaper towards methyl orange dye. The fabricated nanopaper showed an adsorption of 11.05 mg/gm 30 mg/L concentration at pH 2. Maximum adsorption was observed at pH 2 which was due to protonation of amine group. Moreover, the fabricated membrane showed excellent hydrolytic stability which can be corroborated to the surface roughness and reduced hydrophilicity. The investigation into the surface chemistries of cellulose nanofibers beyond the adoption of toxic solvents can enhance the economic usefulness of the process and yield a new eco-friendly adsorbent material that is agreeable to adsorbing various toxic pollutants.
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| 11. |
- Unsalan, Ozan, et al.
(författare)
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The Sariçiçek howardite fall in Turkey : Source crater of HED meteorites on Vesta and impact risk of Vestoids
- 2019
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Ingår i: Meteoritics and Planetary Science. - Hoboken : John Wiley & Sons. - 1086-9379 .- 1945-5100. ; 54:5, s. 953-1008
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Tidskriftsartikel (refereegranskat)abstract
- The Sariçiçek howardite meteorite shower consisting of 343 documented stones occurred on September 2, 2015 in Turkey and is the first documented howardite fall. Cosmogenic isotopes show that Sariçiçek experienced a complex cosmic‐ray exposure history, exposed during ~12–14 Ma in a regolith near the surface of a parent asteroid, and that an ~1 m sized meteoroid was launched by an impact 22 ± 2 Ma ago to Earth (as did one‐third of all HED meteorites). SIMS dating of zircon and baddeleyite yielded 4550.4 ± 2.5 Ma and 4553 ± 8.8 Ma crystallization ages for the basaltic magma clasts. The apatite U‐Pb age of 4525 ± 17 Ma, K‐Ar age of ~3.9 Ga, and the U,Th‐He ages of 1.8 ± 0.7 and 2.6 ± 0.3 Ga are interpreted to represent thermal metamorphic and impact‐related resetting ages, respectively. Petrographic; geochemical; and O‐, Cr‐, and Ti‐isotopic studies confirm that Sariçiçek belongs to the normal clan of HED meteorites. Petrographic observations and analysis of organic material indicate a small portion of carbonaceous chondrite material in the Sariçiçek regolith and organic contamination of the meteorite after a few days on soil. Video observations of the fall show an atmospheric entry at 17.3 ± 0.8 km s−1 from NW; fragmentations at 37, 33, 31, and 27 km altitude; and provide a pre‐atmospheric orbit that is the first dynamical link between the normal HED meteorite clan and the inner Main Belt. Spectral data indicate the similarity of Sariçiçek with the Vesta asteroid family (V‐class) spectra, a group of asteroids stretching to delivery resonances, which includes (4) Vesta. Dynamical modeling of meteoroid delivery to Earth shows that the complete disruption of a ~1 km sized Vesta family asteroid or a ~10 km sized impact crater on Vesta is required to provide sufficient meteoroids ≤4 m in size to account for the influx of meteorites from this HED clan. The 16.7 km diameter Antionia impact crater on Vesta was formed on terrain of the same age as given by the 4He retention age of Sariçiçek. Lunar scaling for crater production to crater counts of its ejecta blanket show it was formed ~22 Ma ago.
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| 12. |
- Vishnu, N., et al.
(författare)
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Mitochondrial clearance of calcium facilitated by MICU2 controls insulin secretion
- 2021
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Ingår i: Molecular Metabolism. - : Elsevier. - 2212-8778. ; 51
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Transport of Ca2+ into pancreatic 13 cell mitochondria facilitates nutrient-mediated insulin secretion. However, the underlying mechanism is unclear. Recent establishment of the molecular identity of the mitochondrial Ca2+ uniporter (MCU) and associated proteins allows modification of mitochondrial Ca2+ transport in intact cells. We examined the consequences of deficiency of the accessory protein MICU2 in rat and human insulin-secreting cells and mouse islets. Methods: siRNA silencing of Micu2 in the INS-1 832/13 and EndoC-13H1 cell lines was performed; Micu2-/- mice were also studied. Insulin secretion and mechanistic analyses utilizing live confocal imaging to assess mitochondrial function and intracellular Ca2+ dynamics were performed. Results: Silencing of Micu2 abrogated GSIS in the INS-1 832/13 and EndoC-13H1 cells. The Micu2-/- mice also displayed attenuated GSIS. Mitochondrial Ca2+ uptake declined in MICU2-deficient INS-1 832/13 and EndoC-13H1 cells in response to high glucose and high K+. MICU2 silencing in INS-1 832/13 cells, presumably through its effects on mitochondrial Ca2+ uptake, perturbed mitochondrial function illustrated by absent mitochondrial membrane hyperpolarization and lowering of the ATP/ADP ratio in response to elevated glucose. Despite the loss of mitochondrial Ca2+ uptake, cytosolic Ca2+ was lower in siMICU2-treated INS-1 832/13 cells in response to high K+. It was hypothesized that Ca2+ accumulated in the submembrane compartment in MICU2-deficient cells, resulting in desensitization of voltage-dependent Ca2+ channels, lowering total cytosolic Ca2+. Upon high K+ stimulation, MICU2-silenced cells showed higher and prolonged increases in submembrane Ca2+ levels. Conclusions: MICU2 plays a critical role in 13 cell mitochondrial Ca2+ uptake. 13 cell mitochondria sequestered Ca2+ from the submembrane compartment, preventing desensitization of voltage-dependent Ca2+ channels and facilitating GSIS.
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| 13. |
- Huner, Norman P A, et al.
(författare)
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Photoprotection of Photosystem II: Reaction center quenching versus antenna quenching
- 2006
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Ingår i: Photoprotection, Photoinhibition, Gene Regulation and Environment. - : Springer. - 9781402035647 ; , s. 155-174
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Photoprotection, Photoinhibition, Gene Regulation, and Environment examines the processes whereby plants monitor environmental conditions and orchestrate their response to change, an ability paramount to the life of all plants. "Excess light", absorbed by the light-harvesting systems of photosynthetic organisms, is an integrative indicator of the environment, communicating the presence of intense light and any conditions unfavorable for growth and photosynthesis. Key plant responses are photoprotection and photoinhibition. In this volume, the dual role of photoprotective responses in the preservation of leaf integrity and in redox signaling networks modulating stress acclimation, growth, and development is addressed. In addition, the still unresolved impact of photoinhibition on plant survival and productivity is discussed. Specific topics include dissipation of excess energy via thermal and other pathways, scavenging of reactive oxygen by antioxidants, proteins key to photoprotection and photoinhibition, peroxidation of lipids, as well as signaling by reactive oxygen, lipid-derived messengers, and other messengers that modulate gene expression. Approaches include biochemical, physiological, genetic, molecular, and field studies, addressing intense visible and ultraviolet light, winter conditions, nutrient deficiency, drought, and salinity. This book is directed toward advanced undergraduate students, graduate students, and researchers interested in Plant Ecology, Stress Physiology, Plant Biochemistry, Integrative Biology, and Photobiology.
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| 14. |
- Ivanov, Alexander G, et al.
(författare)
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Acclimation to temperature and irradiance modulates PSII charge recombination.
- 2006
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Ingår i: FEBS Letters. - : Wiley. - 0014-5793. ; 580:11, s. 2797-802
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Tidskriftsartikel (refereegranskat)abstract
- Acclimation of wild type and the chlorina F2 mutant of barley to either high light or low temperature results in a 2- to 3-fold increase in non-photochemical quenching which occurred independently of either energy-dependent quenching (qE), xanthophyll cycle-mediated antenna quenching or state transitions. Results of in vivo thermoluminescence measurements used to address this conundrum indicated that excitation pressure regulates the temperature gap for Click to view the MathML source and Click to view the MathML source charge recombinations within photosystem II reaction centers. This is discussed in terms of photoprotection through non-radiative charge recombination.
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| 15. |
- Gopakumar, Deepu A., et al.
(författare)
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Carbon dioxide plasma treated PVDF electrospun membrane for the removal of crystal violet dyes and iron oxide nanoparticles from water
- 2019
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Ingår i: Nano-Structures and Nano-Objects. - : Elsevier BV. - 2352-507X. ; 18
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Tidskriftsartikel (refereegranskat)abstract
- Here we reported a reactive plasma treatment of polyvinylidene fluoride (PVDF) electrospun membrane by using carbon dioxide (CO 2 ) plasma in order to reduce the hydrophobicity of the PVDF membrane and thereby used to remove toxic crystal violet dye (CV) and iron oxide (Fe 2 O 3 ) nanoparticles from water. The demonstrated plasma treated PVDF electrospun membrane showed a decrement in the hydrophobicity after plasma treatment. Most of the microfiltration membranes based on PVDF were fabricated via phase inversion technique and solvent casting. The main drawback of these methods is that to obtain membranes with uniform pore size. Moreover, the membranes fabricated via phase inversion and solvent casting process have low surface area whereas in the membranes via electrospinning technique have interconnected pore structure with high surface area and uniform pore size. The contact angle of the neat PVDF electrospun membrane and plasma treated PVDF electrospun membrane were 141°and 102°respectively. FTIR studies revealed that, after CO 2 plasma treatment, highly negative carboxylate (COO-) groups were formed on the surface of the PVDF electrospun membrane. With the 10 mg/L of crystal violet (CV) aqueous solution, the dye adsorption capacity was 1.368 mg/g of the membrane for neat PVDF membrane and 3.84 mg/g of the membrane for plasma treated PVDF membrane. It was found that, the CO 2 plasma treated PVDF membrane had two- or three-times greater adsorption capacity then neat PVDF membrane against crystal violet dyes which was due to the strong electrostatic interaction between the highly negative carboxyl groups on the surface of plasma treated PVDF electrospun membrane and protonated CV dye. Both neat PVDF membrane and plasma treated PVDF membrane showed excellent filtration capacity against Fe 2 O 3 nanoparticles. The demonstrated plasma treated PVDF membrane could successfully remove iron oxide nanoparticles and crystal violet dyes from water via size exclusion and adsorption mechanism respectively.
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| 16. |
- Gopakumar, Deepu A., et al.
(författare)
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Nanocellulose-Based Membranes for Water Purification
- 2019
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Ingår i: Nanoscale Materials in Water Purification. - 9780128139271 ; , s. 59-85
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Scarcity and contamination of worldwide drinking water demand advanced, effective water purification methodologies. Eliminating numerous contaminants, such as heavy metals, toxic textile dyes, pesticides, oil, and other industrial, as well as agricultural, wastes, from water has become a serious concern because of their adverse effects on human health and the ecosystem. Recently, developments in nanoscience and nanotechnology propose that several of the present problems relating to water quality could be greatly reduced by using nanomaterials because of their good adsorption efficiency, higher surface area, and greater active sites for interaction with contaminants in water. In this context, nanocellulose is the most abundant and renewable polymer available globally and consists of repeating β-d-glucopyranose units covalently linked through acetal functions between the hydroxyl groups of C4 and C1 carbon atoms that provide it chirality and reactivity properties. Nanocellulose is a fascinating material for practical applications because it is cost-effective, is renewable, and can be handled at huge scale using conventional wood industry techniques. Nanocellulose is a valuable filtration material because it is affordable, sustainable, inert, and stable at a broad range of pH/ionic strength. Moreover, the abundant availability of the surface hydroxyl groups on the nanocellulose facilitates various surface chemistries that can be explored for targeting various contaminants in water. This chapter covers the recent developments and literature of nanocellulose in the field of water purification.
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| 17. |
- Hasan, M., et al.
(författare)
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Robust superhydrophobic cellulose nanofiber aerogel for multifunctional environmental applications
- 2019
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Ingår i: Polymers. - : MDPI AG. - 2073-4360. ; 11:3
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Tidskriftsartikel (refereegranskat)abstract
- The fabrication of superadsorbent for dye adsorption is a hot research area at present. However, the development of low-cost and highly efficient superadsorbents against toxic textile dyes is still a big challenge. Here, we fabricated hydrophobic cellulose nanofiber aerogels from cellulose nanofibers through an eco-friendly silanization reaction in liquid phase, which is an extremely efficient, rapid, cheap, and environmentally friendly procedure. Moreover, the demonstrated eco-friendly silanization technique is easy to commercialize at the industrial level. Most of the works that have reported on the hydrophobic cellulose nanofiber aerogels explored their use for the elimination of oil from water. The key novelty of the present work is that the demonstrated hydrophobic cellulose nanofibers aerogels could serve as superadsorbents against toxic textile dyes such as crystal violet dye from water and insulating materials for building applications. Here, we make use of the possible hydrophobic interactions between silane-modified cellulose nanofiber aerogel and crystal violet dye for the removal of the crystal violet dye from water. With a 10 mg/L of crystal violet (CV) aqueous solution, the silane-modified cellulose nanofiber aerogel showed a high adsorption capacity value of 150 mg/g of the aerogel. The reason for this adsorption value was due to the short-range hydrophobic interaction between the silane-modified cellulose nanofiber aerogel and the hydrophobic domains in crystal violet dye molecules. Additionally, the fabricated silane-modified cellulose nanofiber hydrophobic aerogels exhibited a lower thermal conductivity value of 0.037 W·m -1 K -1 , which was comparable to and lower than the commercial insulators such as mineral wools (0.040 W·m -1 K -1 ) and polystyrene foams (0.035 W·m -1 K -1 ). We firmly believe that the demonstrated silane-modified cellulose nanofiber aerogel could yield an eco-friendly adsorbent that is agreeable to adsorbing toxic crystal violet dyes from water as well as active building thermal insulators.
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| 18. |
- Ivanov, Alexander G, et al.
(författare)
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Reaction centre quenching of excess light energy and photoprotection of photosystem II
- 2008
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Ingår i: Journal of Plant Biology. ; 51:2, s. 85-96
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Tidskriftsartikel (refereegranskat)abstract
- In addition to the energy dissipation of excess light occurring in PSII antenna via the xanthophyll cycle, there is mounting evidence of a zeaxanthin-independent pathway for non-photochemical quenching based within the PSII reaction centre (reaction centre quenching) that may also play a significant role in photoprotection. It has been demonstrated that acclimation of higher plants, green algae and cyanobacteria to low temperature or high light conditions which potentially induce an imbalance between energy supply and energy utilization is accompanied by the development of higher reduction state of QA and higher resistance to photoinhibition (Huner et al., 1998). Although this is a fundamental feature of all photoautotrophs, and the acquisition of increased tolerance to photoinhibition has been ascribed to growth and development under high PSII excitation pressure, the precise mechanism controlling the redox state of QA and its physiological significance in developing higher resistance to photoinhibition has not been fully elucidated. In this review we summarize recent data indicating that the increased resistance to high light in a broad spectrum of photosynthetic organisms acclimated to high excitation pressure conditions is associated with an increase probability for alternative non-radiative P680+QA − radical pair recombination pathway for energy dissipation within the reaction centre of PSII. The various molecular mechanisms that could account for nonphotochemical quenching through PSII reaction centre are also discussed.
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| 19. |
- Ivanov, Alexander G, et al.
(författare)
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The induction of CP43' by iron-stress in Synechococcus sp. PCC 7942 is associated with carotenoid accumulation and enhanced fatty acid unsaturation.
- 2007
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Ingår i: Biochimica et Biophysica Acta. - : Elsevier BV. - 0006-3002 .- 0005-2728. ; 1767:6, s. 807-13
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Tidskriftsartikel (refereegranskat)abstract
- Comparative lipid analysis demonstrated reduced amount of PG (50%) and lower ratio of MGDG/DGDG in iron-stressed Synechococcus sp. PCC 7942 cells compared to cells grown under iron sufficient conditions. In parallel, the monoenoic (C:1) fatty acids in MGDG, DGDG and PG increased from 46.8%, 43.7% and 45.6%, respectively in control cells to 51.6%, 48.8% and 48.7%, respectively in iron-stressed cells. This suggests increased membrane dynamics, which may facilitate the diffusion of PQ and keep the PQ pool in relatively more oxidized state in iron-stressed compared to control cells. This was confirmed by chlorophyll fluorescence and thermoluminescence measurements. Analysis of carotenoid composition demonstrated that the induction of isiA (CP43′) protein in response to iron stress is accompanied by significant increase of the relative abundance of all carotenoids. The quantity of carotenoids calculated on a Chl basis increased differentially with nostoxanthin, cryptoxanthin, zeaxanthin and β-carotene showing 2.6-, 3.1-, 1.9- and 1.9-fold increases, respectively, while the relative amount of caloxanthin was increased only by 30%. HPLC analyses of the pigment composition of Chl–protein complexes separated by non-denaturating SDS-PAGE demonstrated even higher relative carotenoids content, especially of cryptoxanthin, in trimer and monomer PSI Chl–protein complexes co-migrating with CP43′ from iron-stressed cells than in PSI complexes from control cells where CP43′ is not present. This implies a carotenoid-binding role for the CP43′ protein which supports our previous suggestion for effective energy quenching and photoprotective role of CP43′ protein in cyanobacteria under iron stress.
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| 20. |
- Moon, Woosok, et al.
(författare)
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Physical length scales of wind-blown snow redistribution and accumulation on relatively smooth Arctic first-year sea ice
- 2019
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Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 14:10
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Tidskriftsartikel (refereegranskat)abstract
- Snow thickness measurements over relatively smooth Arctic first-year sea ice, obtained near Cambridge Bay in the Canadian Arctic (2014, 2016 and 2017) and near Elson Lagoon in the Alaskan Arctic (2003 and 2006), are analyzed to quantify physical length-scales and their relevant scaling behaviors. We use the multi-fractal temporally weighted detrended fluctuation analysis method to detect two major physical length-scales from the two independent study locations. Our results suggest that physical processes underlying the formation of snow dunes are consistent and that the wind is the main process shaping the snow thickness variability and redistribution. One scale, around 10 m, appears to be related to the formation of the snow 'dunes', while the other scale, between 30 and 100 m, is likely associated with the various interactions of the snow dunes such as merging, calving and lateral linking. Results imply that snow on level sea ice shows self-organized characteristics.
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| 21. |
- Nypelö, Tiina, 1982, et al.
(författare)
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N2O–Assisted Siphon Foaming of Modified Galactoglucomannans With Cellulose Nanofibers
- 2021
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Ingår i: Frontiers in Chemical Engineering. - : Frontiers Media SA. - 2673-2718. ; 3:11 November
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Tidskriftsartikel (refereegranskat)abstract
- Foaming of most bio-based polymers is challenged by low pore formation and foam stability. At the same time, the developing utilization of bio-based materials for the circular economy is placing new demands for easily processable, low-density materials from renewable raw materials. In this work, we investigate cellulose nanofiber (CNF) foams in which foaming is facilitated with wood-based hemicelluloses, galactoglucomannans (GGMs). Interfacial activity of the GGM is modulated via modification of the molecule’s amphiphilicity, where the surface tension is decreased from approximately 70 to 30 mN m−1 for unmodified and modified GGM, respectively. The chemical modification of GGMs by substitution with butyl glycidyl ether increased the molecule’s hydrophobicity and interaction with the nanocellulose component. The highest specific foam volume using 1 wt% CNF was achieved when modified GGM was added (3.1 ml g−1), compared to unmodified GGM with CNF (2.1 ml g−1). An amount of 96 and 98% of the GGM and GGM-BGE foams were lost after 15 min of foaming while the GGM and GGM-BGE with cellulose nanofibers lost only 33 and 28% of the foam respectively. In the case of GGM-BGE, the foam stability increased with increasing nanofiber concentration. This suggests that the altered hydrophobicity facilitated increased foam formation when the additive was incorporated in the CNF suspension and foamed with nitrous oxide (N2O). Thus, the hydrophobic character of the modified GGM was a necessity for foam formation and stability while the CNFs were needed for generating a self-standing foam structure.
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| 22. |
- Ofori, Jones K., et al.
(författare)
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Elevated miR-130a/miR130b/miR-152 expression reduces intracellular ATP levels in the pancreatic beta cell
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- MicroRNAs have emerged as important players of gene regulation with significant impact in diverse disease processes. In type-2 diabetes, in which impaired insulin secretion is a major factor in disease progression, dysregulated microRNA expression in the insulin-secreting pancreatic beta cell has been widely-implicated. Here, we show that miR-130a-3p, miR-130b-3p, and miR-152-3p levels are elevated in the pancreatic islets of hyperglycaemic donors, corroborating previous findings about their upregulation in the islets of type-2 diabetes model Goto-Kakizaki rats. We demonstrated negative regulatory effects of the three microRNAs on pyruvate dehydrogenase E1 alpha (PDHA1) and on glucokinase (GCK) proteins, which are both involved in ATP production. Consequently, we found both proteins to be downregulated in the Goto-Kakizaki rat islets, while GCK mRNA expression showed reduced trend in the islets of type-2 diabetes donors. Overexpression of any of the three microRNAs in the insulin-secreting INS-1 832/13 cell line resulted in altered dynamics of intracellular ATP/ADP ratio ultimately perturbing fundamental ATP-requiring beta cell processes such as glucose-stimulated insulin secretion, insulin biosynthesis and processing. The data further strengthen the wide-ranging influence of microRNAs in pancreatic beta cell function, and hence their potential as therapeutic targets in type-2 diabetes.
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| 23. |
- Sane, Prafullachandra Vishnu, et al.
(författare)
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Thermoluminescence
- 2012
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Ingår i: Photosynthesis. - Dordrecht : Springer Netherlands. - 9789400715783 - 9789400715790 ; , s. 445-474
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Bokkapitel (refereegranskat)abstract
- Thermo luminescence (TL) of photosynthetic membranes was discovered by William Arnold and Helen Sherwood in 1957. In the last half century, several studies have elucidated the mechanism of TL emission, which showed that the recombination of different charge pairs generated and trapped during pre-illumination are responsible for the observed light emission. Since most of the TL bands originate within Photosystem II (PS II), the technique of TL has become a useful complementary tool to chlorophyll a fluorescence to probe subtle changes in PS II photochemistry. The technique is simple and non-invasive; it has been successfully used to study leaf, cells, thylakoids and even reaction center preparations. The TL technique provides quick information about the redox potential changes of the bound primary quinone (Q(A)) and the secondary quinone (Q(B)) acceptors of PS II; TL has been extensively used to study the effects of photoinhibition, mutations, stresses and myriad responses of the photosynthetic apparatus during acclimation and adaptation. This chapter reviews crucial evidence for the identification of charge pairs responsible for the generation of different TL bands; the relationship of these bands to the components of delayed light emission; responses to excitation pressure arising out of environmental factors; methodology, and instrumentation. A model based on the detailed analysis of the redox shifts of the PS II electron acceptors Q(A) and Q(B), explaining the possibility of non-radiative dissipation of excess light energy within the reaction center of PS II (reaction center quenching) and its physiological significance in photoprotection of the photosynthetic membranes has been suggested. Developments in the analysis of biophysical parameters and the non-adherence of photosynthetic TL to the analysis by the 1945 theory of J.T. Randall and M.H.F. Wilkins have been briefly reviewed.
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| 24. |
- Willatt, Rosemary, et al.
(författare)
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Retrieval of Snow Depth on Arctic Sea Ice From Surface-Based, Polarimetric, Dual-Frequency Radar Altimetry
- 2023
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Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 50:20
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Tidskriftsartikel (refereegranskat)abstract
- Snow depth on sea ice is an Essential Climate Variable and a major source of uncertainty in satellite altimetry-derived sea ice thickness. During winter of the MOSAiC Expedition, the “KuKa” dual-frequency, fully polarized Ku- and Ka-band radar was deployed in “stare” nadir-looking mode to investigate the possibility of combining these two frequencies to retrieve snow depth. Three approaches were investigated: dual-frequency, dual-polarization and waveform shape, and compared to independent snow depth measurements. Novel dual-polarization approaches yielded r2 values up to 0.77. Mean snow depths agreed within 1cm, even for data sub-banded to CryoSat-2 SIRAL and SARAL AltiKa bandwidths. Snow depths from co-polarized dual-frequency approaches were at least a factor of four too small and had a r2 0.15 or lower. r2 for waveform shape techniques reached 0.72 but depths were underestimated. Snow depth retrievals using polarimetric information or waveform shape may therefore be possible from airborne/satellite radar altimeters.
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