| 1. |
- Feigin, Valery L., et al.
(författare)
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Global, regional, and national burden of neurological disorders, 1990–2016 : a systematic analysis for the Global Burden of Disease Study 2016
- 2019
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Ingår i: Lancet Neurology. - : Elsevier. - 1474-4422 .- 1474-4465. ; 18:5, s. 459-480
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Tidskriftsartikel (refereegranskat)abstract
- Background: Neurological disorders are increasingly recognised as major causes of death and disability worldwide. The aim of this analysis from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2016 is to provide the most comprehensive and up-to-date estimates of the global, regional, and national burden from neurological disorders.Methods: We estimated prevalence, incidence, deaths, and disability-adjusted life-years (DALYs; the sum of years of life lost [YLLs] and years lived with disability [YLDs]) by age and sex for 15 neurological disorder categories (tetanus, meningitis, encephalitis, stroke, brain and other CNS cancers, traumatic brain injury, spinal cord injury, Alzheimer's disease and other dementias, Parkinson's disease, multiple sclerosis, motor neuron diseases, idiopathic epilepsy, migraine, tension-type headache, and a residual category for other less common neurological disorders) in 195 countries from 1990 to 2016. DisMod-MR 2.1, a Bayesian meta-regression tool, was the main method of estimation of prevalence and incidence, and the Cause of Death Ensemble model (CODEm) was used for mortality estimation. We quantified the contribution of 84 risks and combinations of risk to the disease estimates for the 15 neurological disorder categories using the GBD comparative risk assessment approach.Findings: Globally, in 2016, neurological disorders were the leading cause of DALYs (276 million [95% UI 247–308]) and second leading cause of deaths (9·0 million [8·8–9·4]). The absolute number of deaths and DALYs from all neurological disorders combined increased (deaths by 39% [34–44] and DALYs by 15% [9–21]) whereas their age-standardised rates decreased (deaths by 28% [26–30] and DALYs by 27% [24–31]) between 1990 and 2016. The only neurological disorders that had a decrease in rates and absolute numbers of deaths and DALYs were tetanus, meningitis, and encephalitis. The four largest contributors of neurological DALYs were stroke (42·2% [38·6–46·1]), migraine (16·3% [11·7–20·8]), Alzheimer's and other dementias (10·4% [9·0–12·1]), and meningitis (7·9% [6·6–10·4]). For the combined neurological disorders, age-standardised DALY rates were significantly higher in males than in females (male-to-female ratio 1·12 [1·05–1·20]), but migraine, multiple sclerosis, and tension-type headache were more common and caused more burden in females, with male-to-female ratios of less than 0·7. The 84 risks quantified in GBD explain less than 10% of neurological disorder DALY burdens, except stroke, for which 88·8% (86·5–90·9) of DALYs are attributable to risk factors, and to a lesser extent Alzheimer's disease and other dementias (22·3% [11·8–35·1] of DALYs are risk attributable) and idiopathic epilepsy (14·1% [10·8–17·5] of DALYs are risk attributable).Interpretation: Globally, the burden of neurological disorders, as measured by the absolute number of DALYs, continues to increase. As populations are growing and ageing, and the prevalence of major disabling neurological disorders steeply increases with age, governments will face increasing demand for treatment, rehabilitation, and support services for neurological disorders. The scarcity of established modifiable risks for most of the neurological burden demonstrates that new knowledge is required to develop effective prevention and treatment strategies.Funding: Bill & Melinda Gates Foundation.
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| 2. |
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| 3. |
- Brännvall, Rickard, 1975-, et al.
(författare)
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Homomorphic encryption enables private data sharing for digital health : Winning entry to the Vinnova innovation competition Vinter 2021-22
- 2022
-
Ingår i: 34th Workshop of the Swedish Artificial Intelligence Society, SAIS 2022. - : Institute of Electrical and Electronics Engineers Inc.. - 9781665471268
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Konferensbidrag (refereegranskat)abstract
- People living with type 1 diabetes often use several apps and devices that help them collect and analyse data for a better monitoring and management of their disease. When such health related data is analysed in the cloud, one must always carefully consider privacy protection and adhere to laws regulating the use of personal data. In this paper we present our experience at the pilot Vinter competition 2021-22 organised by Vinnova. The competition focused on digital services that handle sensitive diabetes related data. The architecture that we proposed for the competition is discussed in the context of a hypothetical cloud-based service that calculates diabetes self-care metrics under strong privacy preservation. It is based on Fully Homomorphic Encryption (FHE)-a technology that makes computation on encrypted data possible. Our solution promotes safe key management and data life-cycle control. Our benchmarking experiment demonstrates execution times that scale well for the implementation of personalised health services. We argue that this technology has great potentials for AI-based health applications and opens up new markets for third-party providers of such services, and will ultimately promote patient health and a trustworthy digital society.
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| 4. |
- Hemmat, Zahra, et al.
(författare)
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Unprecedented Multifunctionality in 1D Nb1-xTaxS3 Transition Metal Trichalcogenide Alloy
- 2022
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Ingår i: Advanced Functional Materials. - : Wiley. - 1616-301X .- 1616-3028. ; 32:34
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Tidskriftsartikel (refereegranskat)abstract
- 1D materials, such as nanofibers or nanoribbons are considered as the future ultimate limit of downscaling for modern electrical and electrochemical devices. Here, for the first time, nanofibers of a solid solution transition metal trichalcogenide (TMTC), Nb1-xTaxS3, are successfully synthesized with outstanding electrical, thermal, and electrochemical characteristics rivaling the performance of the-state-of-the art materials for each application. This material shows nearly unchanged sheet resistance (≈740 Ω sq−1) versus bending cycles tested up to 90 cycles, stable sheet resistance in ambient conditions tested up to 60 days, remarkably high electrical breakdown current density of ≈30 MA cm−2, strong evidence of successive charge density wave transitions, and outstanding thermal stability up to ≈800 K. Additionally, this material demonstrates excellent activity and selectivity for CO2 conversion to CO reaching ≈350 mA cm−2 at −0.8 V versus RHE with a turnover frequency number of 25. It also exhibits an excellent performance in a high-rate Li–air battery with the specific capacity of 3000 mAh g−1 at a current density of 0.3 mA cm−2. This study uncovers the multifunctionality in 1D TMTC alloys for a wide range of applications and opens a new direction for the design of the next generation low-dimensional materials.
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| 5. |
- Jamali, Mohammad Vahid, et al.
(författare)
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Statistical studies of fading in underwater wireless optical channels in the presence of air bubble, temperature, and salinity random variations
- 2018
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Ingår i: IEEE Transactions on Communications. - 0090-6778 .- 1558-0857. ; 66:10, s. 4706-4723
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Tidskriftsartikel (refereegranskat)abstract
- Optical signal propagation through underwater channels is affected by three main degrading phenomena, namely, absorption, scattering, and fading. In this paper, we experimentally study the statistical distribution of intensity fluctuations in underwater wireless optical channels with random temperature and salinity variations, as well as the presence of air bubbles. In particular, we define different scenarios to produce random fluctuations on the water refractive index across the propagation path and, then, examine the accuracy of various statistical distributions in terms of their goodness of fit to the experimental data. We also obtain the channel coherence time to address the average period of fading temporal variations. The scenarios under consideration cover a wide range of scintillation index from weak to strong turbulence. Moreover, the effects of beam-expander-and-collimator (BEC) at the transmitter side and aperture averaging lens (AAL) at the receiver side are experimentally investigated. We show that the use of a transmitter BEC and/or a receiver AAL suits single-lobe distributions, such that the generalized Gamma and exponentiated Weibull distributions can excellently match the histograms of the acquired data. Our experimental results further reveal that the channel coherence time is on the order of 10-3 s and larger which implies to the slow fading turbulent channels.
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| 6. |
- Jaradat, Ahmad, et al.
(författare)
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A High-Rate Li–CO2 Battery Enabled by 2D Medium-Entropy Catalyst
- 2023
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Ingår i: Advanced Functional Materials. - 1616-301X .- 1616-3028. ; 33:21
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Tidskriftsartikel (refereegranskat)abstract
- Lithium-air batteries based on CO2 reactant (Li–CO2) have recently been of interest because it has been found that reversible Li/CO2 electrochemistry is feasible. In this study, a new medium-entropy cathode catalyst, (NbTa)0.5BiS3, that enables the reversible electrochemistry to operate at high rates is presented. This medium entropy cathode catalyst is combined with an ionic liquid-based electrolyte blend to give a Li–CO2 battery that operates at high current density of 5000 mA g−1 and capacity of 5000 mAh g−1 for up to 125 cycles, far exceeding reported values in the literature for this type of battery. The higher rate performance is believed to be due to the greater stability of the multi-element (NbTa)0.5BiS3 catalyst because of its higher entropy compared to previously used catalysts with a smaller number of elements with lower entropies. Evidence for this comes from computational studies giving very low surface energies (high surface stability) for (NbTa)0.5BiS3 and transmission electron microscopystudies showing the structure being retained after cycling. In addition, the calculations indicate that Nb-terminated surface promotes Li–CO2 electrochemistry resulting in Li2CO3 and carbon formation, consistent with the products found in the cell. These results open new direction to design and develop high-performance Li–CO2 batteries.
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| 7. |
- Majidi, Leily, et al.
(författare)
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Nanostructured Conductive Metal Organic Frameworks for Sustainable Low Charge Overpotentials in Li-Air Batteries
- 2022
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 18:4
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Tidskriftsartikel (refereegranskat)abstract
- Lithium–oxygen batteries are among the most attractive alternatives for future electrified transportation. However, their practical application is hindered by many obstacles. Due to the insulating nature of Li2O2 product and the slow kinetics of reactions, attaining sustainable low charge overpotentials at high rates becomes a challenge resulting in the battery's early failure and low round trip efficiency. Herein, outstanding characteristics are discovered of a conductive metal organic framework (c-MOF) that promotes the growth of nanocrystalline Li2O2 with amorphous regions. This provides a platform for the continuous growth of Li2O2 units away from framework, enabling a fast discharge at high current rates. Moreover, the Li2O2 structure works in synergy with the redox mediator (RM). The conductivity of the amorphous regions of the Li2O2 allows the RM to act directly on the Li2O2 surface instead of catalyst edges and then transport through the electrolyte to the Li2O2 surface. This direct charge transfer enables a small charge potential of <3.7 V under high current densities (1–2 A g−1) sustained for a long cycle life (100–300 cycles) for large capacities (1000–2000 mAh g−1). These results open a new direction for utilizing c-MOFs towards advanced energy storage systems.
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| 8. |
- Pagès, Guilhem, et al.
(författare)
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Vegetable oil reactions within wood studied by direct 13C excitation with 1H decoupling and magic-angle sample spinning (MAS) NMR
- 2012
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Ingår i: Progress in organic coatings. - : Elsevier BV. - 0300-9440 .- 1873-331X. ; 75:3, s. 259-263
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Forskningsöversikt (refereegranskat)abstract
- Despite having been used for ages to protect wood against the influence of outdoor elements, the chemistry of vegetable oils within wood is poorly known. We propose a method based on solid-state magic-angle sample spinning NMR to in situ characterize oil oxidation as well as its immobilization. To eliminate signal coming from wood molecules but to keep signal from the oil, direct 13C excitation is performed with low-power 1H decoupling during signal acquisition. To suppress the effect of anisotropic spin-interactions and magnetic field inhomogeneity, the sample is spun at the magic-angle. Mono- and polyunsaturated fatty acid derivatives show a difference in their oxidation process: the monounsaturated methyl oleate reacts with wood components and becomes immobilized while the polyunsaturated methyl linoleate becomes oxidized and form oligomers but does not seem to bind to wood. Linola ® oil behaves as would be expected on the basis of its composition by monounsaturated and polyunsaturated chains. This method can be generalized to all coating treatments to characterize chemical pathways and reactions. A better understanding of coating effects on wood is a crucial step to design more efficient protective mixtures.
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| 9. |
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| 10. |
- Salehi, Alireza, et al.
(författare)
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A Management Model for Persian Oak -- A Model for Management of Mixed Coppice Stands of Semiarid Forests of Persian Oak
- 2010
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Ingår i: Mathematical and Computational Forestry and Natural-Resource Sciences. - 1946-7664. ; 2, s. 20-29
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Tidskriftsartikel (refereegranskat)abstract
- This study aims to present a diameter class model to predict the effects of different forest management practices on growth and yield conditions of the mixed coppice stands of Persian oak (Quercus persica) in the semiarid forests in southern Zagros, Iran. Using inventory data in 2003, the model was applied to make management recommendations for a forested watershed. Some requested data for the model were extracted from available information on an adjacent forested area. The model was analyzed under a set of different management strategies considering uneven-aged forest management. Linear programming was used to solve the problems. The model yields results of importance for policy development. For instance, the present prohibition of harvests could be counterproductive as some 10–20 times more volume can be extracted when harvests are allowed. In addition, the effect of improved protection of natural regeneration from grazing seems only to be justified if it is combined with harvesting trees. These conclusions should however be considered with great caution as the calculated model parameters hinge on a number of critical assumptions. Sensitivity analyses with the model could show what parameters are critical and therefore motivate research with permanent field trials
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| 11. |
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| 12. |
- Salehi, Alireza M., et al.
(författare)
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Serum profiling of anorexia nervosa : A 1H NMR-based metabolomics study
- 2021
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Ingår i: European Neuropsychopharmacology. - : Elsevier. - 0924-977X .- 1873-7862. ; 49, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Our understanding of pathophysiological mechanisms underlying anorexia nervosa (AN) is incomplete. The aim was to conduct a metabolomics profiling of serum samples from women with AN (n = 65), women who have recovered from AN (AN-REC, n = 65), and age-matched healthy female controls (HC, n = 65). Serum concentrations of 21 metabolites were measured using proton nuclear magnetic resonance (1H NMR). We used orthogonal partial least-squares discriminant analysis (OPLS-DA) modeling to assign group classification based on the metabolites. Analysis of variance (ANOVA) was used to test for metabolite concentration differences across groups. The OPLS-DA model could distinguish between the AN and HC groups (p = 9.05 × 10–11 R2Y = 0.36, Q2 = 0.37) and between the AN-REC and HC groups (p = 8.47 × 10–6, R2Y = 0.36, Q2 = 0.24,), but not between the AN and AN-REC groups (p = 0.63). Lower methanol concentration in the AN and AN-REC group explained most of the variance. Likewise, the strongest finding in the univariate analyses was lower serum methanol concentration in both AN and AN-REC compared with HC, which withstood adjustment for body mass index (BMI). We report for the first time lower serum concentrations of methanol in AN. The fact that low methanol was also found in recovered AN suggests that low serum concentration of methanol could either be trait marker or a scar effect of AN.
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| 13. |
- Salehi M., Alireza
(författare)
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Chemical Interactions between Fatty Acids and Wood Components during Oxidation Processes
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Fatty acids auto-oxidation on wood is proposed to follow a complex free radical interaction mechanism. The aim of this study was to analyze the effect of wood constituents on oxidation of fatty acids and thereby the entire drying process, and to characterize the fatty acids-wood interaction by using analytical instruments such as RT-IR and NMR.The auto-oxidation process of polyunsaturated fatty acids was analyzed in combination with wood model compounds, softwood and hardwood. The results showed that the oxidative drying process of unsaturated fatty acids was indeed affected by wood constituents. Wood morphology is heterogeneous and porous. A problematic issue in fatty acid-wood system is its heterogeneity and complexity.The most hydrophobic polymer of the main constituents of wood is lignin and it interacted with the oxidation process and lignin structures inhibited or retarded the reaction. However, wood carbohydrates such as lactose and sucrose increased the rate of fatty acids oxidation, thus carbohydrates may function as catalysts.The fatty acids pattern affects not only the structure of the dried oil itself but also the surrounding wood materials. Not only the oil structures were affected but also the lignin was to some extent oxidized as a competing reaction with the oil oxidation. Further, a formation of chemical bonds between the oil and the lignin structures was not observed, i.e. the oils were not immobilized on lignin by covalent bond formation to any significant extent. The analysis on oils in wood using NMR and FTIR demonstrated that highly reactive linoleic acid interacted in wood significantly, while it was not immobilized to the same extent. Oleic acid on the other hand interacted more slowly but was immobilized in the wood structure.A number of wood species (hardwood and softwood) were tested for how they affected the drying process, where Norway spruce dried the fastest and hazelwood the slowest. Generally it appeared to be a connection between high density and slow drying. It can thus be concluded that different wood components affect the oil drying process in different ways. According to the results, it can also be concluded that the structure of the oil and different wood species are crucial in the overall protective performance of the system.
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| 14. |
- Salehi Movahed, Alireza, et al.
(författare)
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Effect of model lignin structures on the oxidation of unsaturated fatty acids
- 2010
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Ingår i: Polymers from Renewable Resources. - : SAGE Publications. - 2041-2479 .- 2045-1377. ; 1:2
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study is to better understand vegetable oils as raw materials in the application of wood protection in order to obtain improved durability of exterior wood materials in an environmentally friendly way. This was done by studying the effect of lignin model compounds on the auto-oxidation rate of methyl linoleate. The auto-oxidation process of methyl linoleate was measured by itself and in combination with 1 wt% phenolic and non-phenolic lignin model compounds at 70°C. The effect of lignin compounds on the methyl linoleate auto-oxidation process was monitored by 1H-NMR, size exclusion chromatography (SEC), and real-time infrared spectroscopy (RT-IR). It was observed that phenolic groups and radical conjugation are the main contributors to an antioxidant effect of lignin compounds on the oxidation rate of the methyl linoleate. Ferulic acid, which is phenolic and contains a carboxylic group, has the largest antioxidant effect on methyl linoleate. It was also found that the antioxidant effect existed, despite the low solubility of ferulic acid in methyl linoleate. This research demonstrates that it is possible to follow the auto-oxidation process in real time to uncover the effects of wood constituents on the fatty acid auto-oxidation process. Additionally, this knowledge that drying rate of oil can be tuned with the addition of lignin compounds can be used to predict drying times when this oil is applied to different species of wood.
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| 15. |
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| 16. |
- Salehi Movahed, Alireza, et al.
(författare)
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Effect of wood carbohydrates on the oxidation of unsaturated fatty acids
- 2013
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Ingår i: Progress in organic coatings. - : Elsevier BV. - 0300-9440 .- 1873-331X. ; 76:7/8, s. 1068-1074
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study is to better understand the oxidation mechanism of the fatty acids applied on wood surfaces. In the present study, model hemicellulose compounds were used to measure the effect of polysaccharides on auto-oxidation of methyl linoleate utilizing infrared spectroscopy (RT-IR). The auto-oxidation process of methyl linoleate was measured in combination with 1 wt% reducing and non-reducing hemicellulose model compounds (HMC) at 70 degrees C. The effect of HMC on the methyl linoleate auto-oxidation process was also compared with the effects of glycerol and glyceraldehyde, using same analytical method and reaction conditions. The IR-spectra of methyl linoleate with 1 wt% carbohydrates before and after oxidation were analyzed and peak intensity variations during oxidation in the region of 3010 cm(-1), 990 cm(-1), and 970 cm(-1) were calculated during oxidation process. It was observed that lactose and sucrose accelerated the radical reactions; however, glycerol has an anti-oxidative effect on the fatty acids oxidation. An interaction mechanism for these findings is proposed and discussed.
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| 17. |
- Salehi Movahed, Alireza
(författare)
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Effect of Wood Constituents Oxidation of Unsaturated Fatty Acids
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This work presents the mechanisms of free radicals in a model system between fatty acids oxidation process and wood components. The aim is to create a better understanding of new environmentally friendly materials for exterior wood protection. The drying mechanisms of the unsaturated fatty acids with wood model system in the real time were monitored by using RT-IR. This method together with SEC and NMR are enormously powerful spectroscopy techniques to determine the physical and chemical properties of fatty acids-wood during the oxidation process over time. In the first part of this study the focus was in a molecular level on oxidation of methyl linoleate mixed with lignin model compounds (1 and 20 wt%). The effect of lignin structures on unsaturation fatty acids oxidation was determined with 1 wt% lignin model compounds. The interaction, coupling reaction and new structure formations were analyzed through 20 wt% of same lignin compounds mixed with 80 wt% methyl linoleate. The oil oxidation interaction mechanisms were also evaluated by using methyl linoleate, methyl oleate and Linola® on real/natural wood (Norwegian Spruce). In the second part of this work, FT-IR and different NMR methods were used as characterization techniques. The results showed that the oxidative drying process of unsaturated fatty acids was indeed affected by wood constituents. The most hydrophobic part of the wood; lignin, interacted with the oxidation process and some lignin structures inhibited or retarded the reaction. Not only the oil structures were affected but also the lignins were to some extent oxidized as a competing reaction with the oil oxidation. However, a formation of chemicals bonds between the oil and the lignin structures was not observed, i.e. the oils were not immobilized on lignin by covalent bond formation to any significant extent. Further, the focus was on oils in wood using NMR and FTIR demonstrated that highly reactive linoleic acid did react in wood significantly, while it was not immobilized to the same extent. Oleic acid on the other hand reacted more sluggish but the reactive part was immobilized in the wood structure. According to the results, it can be concluded that the structure of the oil is crucial in the overall protective performance of the system. This study indicated that the oxidation pattern of fatty acids behaved differently on wood surface. The wood model compounds minimize the complexity of all elements that exist normally in the natural wood. It can also be concluded that different wood components e.g. end group structures, affect the oil drying process in different ways. The fatty acids pattern will affect not only the structure of the oil dried itself but also the surrounding wood materials.
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| 18. |
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| 19. |
- Salehi Muhaved, Alireza, et al.
(författare)
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Oxidation of methyl linoleate in the presence of lignin
- 2011
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Ingår i: Progress in organic coatings. - : Elsevier BV. - 0300-9440 .- 1873-331X. ; 72:3, s. 325-333
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Tidskriftsartikel (refereegranskat)abstract
- The overall aim of this study is to develop new wood modifications using vegetable oils to obtain improved durability of wood materials in an environmentally friendly way. Nuclear magnetic resonance (NMR) and Fourier-transform infrared (FT-IR) spectroscopies were used to study oxidation and possible chemical coupling reactions between polyunsaturated fatty acids and model lignin compounds in order to better understand the interactions between oxidatively drying systems such as vegetable oils or alkyds with the lignin part in wood. This was done by studying mixtures of different model lignin compounds and methyl linoleate. The oxidation process was analyzed at 70 °C both in methyl linoleate alone and in combination with 20 wt% of lignin model compounds. The effects of those compounds on the oil polymerization processes were monitored by NMR (both 13C and 1H experiments) and the domain specific reactivity and patterning were then combined with FT-IR data. No covalent bonds having formed between the oil and the model compounds were detected by combination of several 13C/1H 2D NMR methods. From the spectra, the oxidation degrees of model compounds were calculated, and for some lignin model compounds alcohols were oxidized to carbonyls during the process. Those results were in excellent agreement with FT-IR data and oxidation mechanisms were proposed. The combination of both analytical techniques was necessary to have a better understanding of these systems: NMR demonstrated the absence of chemical bond and quantified oxidation degree of model lignin molecules while FT-IR focused on oil oxidation.
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| 20. |
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| 21. |
- Sharifi-Yazdi, Masoud, et al.
(författare)
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Influence of the Late Quaternary climate on sedimentology of the Jazmurian Playa, SE Iran
- 2022
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Ingår i: Journal of Paleolimnology. - : SPRINGER. - 0921-2728 .- 1573-0417. ; 68, s. 169-187
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Tidskriftsartikel (refereegranskat)abstract
- The Jazmurian Playa in southeast Iran is a sediment archive that has preserved a record of climate and environmental changes since the late Pleistocene. The late Pleistocene was dominated by sub-arid to arid climate interspersed with short periods of warm and humid conditions that impacted the vegetation cover and landscape. This study used sedimentological variations in a sediment core, supported by geochemical and mineralogical characteristics, to reconstruct climate change impacts and water-level fluctuations in the playa. These changes were inferred using grain-size data, magnetic susceptibility, total organic matter content, carbonate content, elemental concentrations, and mineralogical composition in a C-14-dated sediment core. Based on the inferred water level fluctuations in the playa, the core was divided into two major units. Unit 2 belonged to the late Pleistocene, characterized by a cold and dry climate. In contrast, Unit 1 was deposited during the Holocene, a time marked by prevailing warm and humid conditions, with short periods of intense dust storms. Since the late Holocene, the IOSM (Indian Ocean Summer Monsoon) has played a dominant role in regional climate. Water-level fluctuations related to humidity significantly influenced the sedimentological variables, including grain-size distribution, sorting, skewness, and roundness. During cold and arid conditions, the water level was low, and coarse sediments were deposited in the playa, with low organic matter content, low concentrations of Cu, Mn, P, and V, and evaporite minerals. In contrast, high organic matter content, presence of illite, and high concentrations of Cu, Mn, P, and V and low values of ICV (Index of Compositional Variability) imply a warm and humid climate during the Holocene. The paleoclimate reconstruction in the playa provides evidence about ongoing changes that are closely related to the paleohydrological conditions in this region.
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| 22. |
- Smedler, Erik, et al.
(författare)
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Metabolomics analysis of cerebrospinal fluid suggests citric acid cycle aberrations in bipolar disorder
- 2022
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Ingår i: Neuroscience Applied. - : Elsevier BV. - 2772-4085. ; 1
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Tidskriftsartikel (refereegranskat)abstract
- Mounting evidence indicates mitochondrial dysfunction in bipolar disorder pathophysiology. Here, we employed Proton Nuclear Magnetic Resonance Spectroscopy (1H NMR) of cerebrospinal fluid (CSF) samples from well-characterized bipolar disorder patients (n = 67) and healthy controls (n = 55) in order to measure absolute concentrations of multiple metabolites. Focusing on four citric acid cycle metabolites — citrate, glucose, lactate, and pyruvate — we found higher concentrations of both citrate and glucose in patients compared with controls after correcting for age, sex and body mass index, but only the difference in CSF citrate survived correction for multiple comparisons. Within the patient group, CSF citrate concentrations were higher among lithium users than non-users. In conclusion, this report adds further evidence for a mitochondrial dysfunction in bipolar disorder.
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| 23. |
- Valijam, Shayan, et al.
(författare)
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Design of a low-voltage dielectrophoresis lab-on-the chip to separate tumor and blood cells
- 2023
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Ingår i: Microfluidics and Nanofluidics. - : Springer Berlin/Heidelberg. - 1613-4982 .- 1613-4990. ; 27:3
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we design and propose a compact label-free microfluidic lab-on-a-chip device to separate circulating tumor cells (CTCs) from red blood cells (RBCs) at low voltage to minimize cell damage. With the aim of developing a mm-long device to perform cell separation, we used 3D finite element simulation modeling and investigated separation efficiency for different electrode configurations, electrode shapes, and channel heights. Our results show that configuring the electrodes as two arrays, consisting of only five pairs of top and bottom planar electrodes shifted relative to each other and energized with ± 6 V at 70 kHz, generates sufficient non-uniform electric fields to separate CTCs and RBCs in a 2 mm long channel. The advantage of the proposed design is the simplicity of the electrode arrangement and that the electrodes do not cover the central part of the channel, thus allowing for brightfield imaging of the channel. In addition, the low voltage needed and the 50 µm high channel reduce the Joule heating effect and improve the device's separation and throughput efficiency. We suggest that the proposed design would be effective for separating CTCs and RBCs and, thus, used as a device for the early detection of CTCs.
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| 24. |
- Valijam, Shayan, et al.
(författare)
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Fabricating a dielectrophoretic microfluidic device using 3D-printed moulds and silver conductive paint
- 2023
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Dielectrophoresis is an electric field-based technique for moving neutral particles through a fluid. When used for particle separation, dielectrophoresis has many advantages compared to other methods, like providing label-free operation with greater control of the separation forces. In this paper, we design, build, and test a low-voltage dielectrophoretic device using a 3D printing approach. This lab-on-a-chip device fits on a microscope glass slide and incorporates microfluidic channels for particle separation. First, we use multiphysics simulations to evaluate the separation efficiency of the prospective device and guide the design process. Second, we fabricate the device in PDMS (polydimethylsiloxane) by using 3D-printed moulds that contain patterns of the channels and electrodes. The imprint of the electrodes is then filled with silver conductive paint, making a 9-pole comb electrode. Lastly, we evaluate the separation efficiency of our device by introducing a mixture of 3 μm and 10 μm polystyrene particles and tracking their progression. Our device is able to efficiently separate these particles when the electrodes are energized with ±12 V at 75 kHz. Overall, our method allows the fabrication of cheap and effective dielectrophoretic microfluidic devices using commercial off-the-shelf equipment.
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| 25. |
- Wang, Shuxi, et al.
(författare)
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Thermodynamics and Kinetics in Anisotropic Growth of One-Dimensional Midentropy Nanoribbons
- 2023
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Ingår i: ACS Nano. - 1936-0851 .- 1936-086X. ; 17:15, s. 15053-15064
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Tidskriftsartikel (refereegranskat)abstract
- One-dimensional (1D) materials demonstrate anisotropic in-plane physical properties that enable a wide range of functionalities in electronics, photonics, valleytronics, optoelectronics, and catalysis. Here, we undertake an in-depth study of the growth mechanism for equimolar midentropy alloy of (NbTaTi)0.33S3 nanoribbons as a model system for 1D transition metal trichalcogenide structures. To understand the thermodynamic and kinetic effects in the growth process, the energetically preferred phases at different synthesis temperatures and times are investigated, and the phase evolution is inspected at a sequence of growth steps. It is uncovered that the dynamics of the growth process occurs at four different stages via preferential incorporation of chemical species at high-surface-energy facets. Also, a sequence of temperature and time dependent nonuniform to uniform phase evolutions has emerged in the composition and structure of (NbTaTi)0.33S3 which is described based on an anisotropic vapor–solid (V–S) mechanism. Furthermore, direct evidence for the 3D structure of the charge density wave (CDW) phase (width less than 100 nm) is provided by three-dimensional electron diffraction (3DED) in individual nanoribbons at cryogenic temperature, and detailed comparisons are made between the phases obtained before and after CDW transformation. This study provides important fundamental information for the design and synthesis of future 1D alloy structures.
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