| 1. |
- Thomas, HS, et al.
(författare)
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- 2019
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swepub:Mat__t
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| 2. |
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| 3. |
- Bravo, L, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 4. |
- Tabiri, S, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 5. |
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| 6. |
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| 7. |
- Tran, K. B., et al.
(författare)
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The global burden of cancer attributable to risk factors, 2010-19: a systematic analysis for the Global Burden of Disease Study 2019
- 2022
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Ingår i: Lancet. - 0140-6736. ; 400:10352, s. 563-591
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Tidskriftsartikel (refereegranskat)abstract
- Background Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. Methods The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk-outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. Findings Globally, in 2019, the risk factors included in this analysis accounted for 4.45 million (95% uncertainty interval 4.01-4.94) deaths and 105 million (95.0-116) DALYs for both sexes combined, representing 44.4% (41.3-48.4) of all cancer deaths and 42.0% (39.1-45.6) of all DALYs. There were 2.88 million (2.60-3.18) risk-attributable cancer deaths in males (50.6% [47.8-54.1] of all male cancer deaths) and 1.58 million (1.36-1.84) risk-attributable cancer deaths in females (36.3% [32.5-41.3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20.4% (12.6-28.4) and DALYs by 16.8% (8.8-25.0), with the greatest percentage increase in metabolic risks (34.7% [27.9-42.8] and 33.3% [25.8-42.0]). Interpretation The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.
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| 8. |
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| 9. |
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| 10. |
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| 11. |
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| 12. |
- Sheena, B. S., et al.
(författare)
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Global, regional, and national burden of hepatitis B, 1990-2019: a systematic analysis for the Global Burden of Disease Study 2019
- 2022
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Ingår i: Lancet Gastroenterology & Hepatology. - : Elsevier BV. - 2468-1253. ; 7:9, s. 796-829
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Tidskriftsartikel (refereegranskat)abstract
- Background Combating viral hepatitis is part of the UN Sustainable Development Goals (SDGs), and WHO has put forth hepatitis B elimination targets in its Global Health Sector Strategy on Viral Hepatitis (WHO-GHSS) and Interim Guidance for Country Validation of Viral Hepatitis Elimination (WHO Interim Guidance). We estimated the global, regional, and national prevalence of hepatitis B virus (HBV), as well as mortality and disability-adjusted life-years (DALYs) due to HBV, as part of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019. This included estimates for 194 WHO member states, for which we compared our estimates to WHO elimination targets. Methods The primary data sources were population-based serosurveys, claims and hospital discharges, cancer registries, vital registration systems, and published case series. We estimated chronic HBV infection and the burden of HBV-related diseases, defined as an aggregate of cirrhosis due to hepatitis B, liver cancer due to hepatitis B, and acute hepatitis B. We used DisMod-MR 2.1, a Bayesian mixed-effects meta-regression tool, to estimate the prevalence of chronic HBV infection, cirrhosis, and aetiological proportions of cirrhosis. We used mortality-to-incidence ratios modelled with spatiotemporal Gaussian process regression to estimate the incidence of liver cancer. We used the Cause of Death Ensemble modelling (CODEm) model, a tool that selects models and covariates on the basis of out-ofsample performance, to estimate mortality due to cirrhosis, liver cancer, and acute hepatitis B. Findings In 2019, the estimated global, all-age prevalence of chronic HBV infection was 4 center dot 1% (95% uncertainty interval [UI] 3 center dot 7 to 4 center dot 5), corresponding to 316 million (284 to 351) infected people. There was a 31 center dot 3% (29 center dot 0 to 33 center dot 9) decline in all-age prevalence between 1990 and 2019, with a more marked decline of 76 center dot 8% (76 center dot 2 to 77 center dot 5) in prevalence in children younger than 5 years. HBV-related diseases resulted in 555 000 global deaths (487 000 to 630 000) in 2019. The number of HBV-related deaths increased between 1990 and 2019 (by 5 center dot 9% [-5 center dot 6 to 19 center dot 2]) and between 2015 and 2019 (by 2 center dot 9% [-5 center dot 9 to 11 center dot 3]). By contrast, all-age and age-standardised death rates due to HBV-related diseases decreased during these periods. We compared estimates for 2019 in 194 WHO locations to WHO-GHSS 2020 targets, and found that four countries achieved a 10% reduction in deaths, 15 countries achieved a 30% reduction in new cases, and 147 countries achieved a 1% prevalence in children younger than 5 years. As of 2019, 68 of 194 countries had already achieved the 2030 target proposed in WHO Interim Guidance of an all-age HBV-related death rate of four per 100 000. Interpretation The prevalence of chronic HBV infection declined over time, particularly in children younger than 5 years, since the introduction of hepatitis B vaccination. HBV-related death rates also decreased, but HBV-related death counts increased as a result of population growth, ageing, and cohort effects. By 2019, many countries had met the interim seroprevalence target for children younger than 5 years, but few countries had met the WHO-GHSS interim targets for deaths and new cases. Progress according to all indicators must be accelerated to meet 2030 targets, and there are marked disparities in burden and progress across the world. HBV interventions, such as vaccination, testing, and treatment, must be strategically supported and scaled up to achieve elimination.
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| 13. |
- Ahmad, Naveed, et al.
(författare)
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The inter-relation of corporate social responsibility at employee level, servant leadership, and innovative work behavior in the time of crisis from the healthcare sector of pakistan
- 2021
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Ingår i: International Journal of Environmental Research and Public Health. - : MDPI AG. - 1661-7827 .- 1660-4601. ; 18:9
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Tidskriftsartikel (refereegranskat)abstract
- Organizational crisis can serve as a base to provide an opportunity to an organization for enhancing individuals, organizations, and communities. The healthcare sector is one of those sectors that remains under continuous pressure to provide high-quality service delivery to the patients. Hence, the requirement of innovation for this sector is huge when compared to other sectors. The majority of the previous studies have investigated the phenomenon of CSR at the employee’s level (CSR-E) to influence employee behavior positively. However, the importance of CSR-E to enhance the innovative capability of the employees at the workplace is not well-explored in extant literature. Moreover, it is not clear from previous studies how the concept of servant leadership can explain the employee’s engagement towards innovative work behavior (EIB). Thus, the current survey aims to test the relationship of CSR-E and EIB in the healthcare sector of Pakistan with the mediating effect of servant leadership. The data of the current study were obtained through a self-administered (paper-pencil) survey and they were analyzed through the structural equation modeling (SEM) technique. The empirical results of SEM analysis revealed that CSR-E and EIB are positively related and servant leadership partially mediates this relationship. The findings of the current study will be helpful for policymakers to improve their understanding towards CSR-E to induce EIB in the time of crisis. At the same time, the current study also highlights the importance of servant leadership to the policymakers in encouraging the employees to display their innovative capability at the workplace to serve their organization during the time of crisis.
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| 14. |
- Alvarez, E. M., et al.
(författare)
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The global burden of adolescent and young adult cancer in 2019: a systematic analysis for the Global Burden of Disease Study 2019
- 2022
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Ingår i: Lancet Oncology. - : Elsevier BV. - 1470-2045. ; 23:1, s. 27-52
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Tidskriftsartikel (refereegranskat)abstract
- Background In estimating the global burden of cancer, adolescents and young adults with cancer are often overlooked, despite being a distinct subgroup with unique epidemiology, clinical care needs, and societal impact. Comprehensive estimates of the global cancer burden in adolescents and young adults (aged 15-39 years) are lacking. To address this gap, we analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, with a focus on the outcome of disability-adjusted life-years (DALYs), to inform global cancer control measures in adolescents and young adults. Methods Using the GBD 2019 methodology, international mortality data were collected from vital registration systems, verbal autopsies, and population-based cancer registry inputs modelled with mortality-to-incidence ratios (MIRs). Incidence was computed with mortality estimates and corresponding MIRs. Prevalence estimates were calculated using modelled survival and multiplied by disability weights to obtain years lived with disability (YLDs). Years of life lost (YLLs) were calculated as age-specific cancer deaths multiplied by the standard life expectancy at the age of death. The main outcome was DALYs (the sum of YLLs and YLDs). Estimates were presented globally and by Socio-demographic Index (SDI) quintiles (countries ranked and divided into five equal SDI groups), and all estimates were presented with corresponding 95% uncertainty intervals (UIs). For this analysis, we used the age range of 15-39 years to define adolescents and young adults. Findings There were 1.19 million (95% UI 1.11-1.28) incident cancer cases and 396 000 (370 000-425 000) deaths due to cancer among people aged 15-39 years worldwide in 2019. The highest age-standardised incidence rates occurred in high SDI (59.6 [54.5-65.7] per 100 000 person-years) and high-middle SDI countries (53.2 [48.8-57.9] per 100 000 person-years), while the highest age-standardised mortality rates were in low-middle SDI (14.2 [12.9-15.6] per 100 000 person-years) and middle SDI (13.6 [12.6-14.8] per 100 000 person-years) countries. In 2019, adolescent and young adult cancers contributed 23.5 million (21.9-25.2) DALYs to the global burden of disease, of which 2.7% (1.9-3.6) came from YLDs and 97.3% (96.4-98.1) from YLLs. Cancer was the fourth leading cause of death and tenth leading cause of DALYs in adolescents and young adults globally. Interpretation Adolescent and young adult cancers contributed substantially to the overall adolescent and young adult disease burden globally in 2019. These results provide new insights into the distribution and magnitude of the adolescent and young adult cancer burden around the world. With notable differences observed across SDI settings, these estimates can inform global and country-level cancer control efforts. Copyright (C) 2021 The Author(s). Published by Elsevier Ltd.
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| 15. |
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| 16. |
- Arshad, Wajiha, et al.
(författare)
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A rare case of retropharyngeal liposarcoma : a rare location of a rare diagnosis
- 2023
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Ingår i: Journal of Surgical Case Reports. - : Oxford University Press (OUP). - 2042-8812. ; 2023:3
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Tidskriftsartikel (refereegranskat)abstract
- We report a case of retropharyngeal liposarcoma in a 53-year-old female, who had complaints of neck swelling accompanied with dysphagia, orthopnea and dysphonia. Clinical examination revealed huge multinodular swelling in front of neck with bilateral extension, more prominent on left side and moving with deglutition. The diagnosis of retropharyngeal liposarcoma was established following CT scan, MRI and incisional biopsy. Surgical excision of mass along with near total thyroidectomy was performed. Postoperative hospital stay was uneventful. She remained well in follow-up period of 1 year as well. In conclusion, retropharyngeal liposarcoma is a rare tumor. A review of the literature explores the reasons behind the late presentation as well as the difficulties in diagnosis and treatment of this rare tumor.
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| 17. |
- Shahzad, Danish, et al.
(författare)
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Novel C-2 Symmetric Molecules as -Glucosidase and -Amylase Inhibitors : Design, Synthesis, Kinetic Evaluation, Molecular Docking and Pharmacokinetics
- 2019
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Ingår i: Molecules. - : MDPI. - 1431-5157 .- 1420-3049. ; 24:8
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Tidskriftsartikel (refereegranskat)abstract
- A series of symmetrical salicylaldehyde-bishydrazine azo molecules, 5a-5h, have been synthesized, characterized by H-1-NMR and C-13-NMR, and evaluated for their in vitro -glucosidase and -amylase inhibitory activities. All the synthesized compounds efficiently inhibited both enzymes. Compound 5g was the most potent derivative in the series, and powerfully inhibited both -glucosidase and -amylase. The IC50 of 5g against -glucosidase was 0.35917 +/- 0.0189 mu M (standard acarbose IC50 = 6.109 +/- 0.329 mu M), and the IC50 value of 5g against -amylase was 0.4379 +/- 0.0423 mu M (standard acarbose IC50 = 33.178 +/- 2.392 mu M). The Lineweaver-Burk plot indicated that compound 5g is a competitive inhibitor of -glucosidase. The binding interactions of the most active analogues were confirmed through molecular docking studies. Docking studies showed that 5g interacts with the residues Trp690, Asp548, Arg425, and Glu426, which form hydrogen bonds to 5g with distances of 2.05, 2.20, 2.10 and 2.18 angstrom, respectively. All compounds showed high mutagenic and tumorigenic behaviors, and only 5e showed irritant properties. In addition, all the derivatives showed good antioxidant activities. The pharmacokinetic evaluation also revealed promising results
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| 18. |
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| 19. |
- Abbasi, Umar Aftab, et al.
(författare)
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Biological, structural and functional responses of tropical forests to environmental factors
- 2022
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Ingår i: Biological Conservation. - : Elsevier BV. - 0006-3207 .- 1873-2917. ; 276, s. 109792-109792
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Tidskriftsartikel (refereegranskat)abstract
- Here, we hypothesize that the biological, structural and functional attributes of tropical forests respond to water-related climatic and soil nutrient-related factors.Thus, we quantified 27 forest attributes and 20 environmental factors across 189 plots of Sri Lankan tropical forests. Our results suggest that environmental conditions were characterized by both water-related and temperature-related factors, and as such, both coarse-textured and compacted-structured soils determined soil conditions.Forest conditions were characterized by high species-functional diversity, structural complexity and aboveground biomass-related functions. We found strong positive effects of water-related climatic factors followed by temperature-related climatic factors but negligible positive to negative effects of textured-related and nutrient-related soil factors on most of the biological, structural and functional attributes.Overall the biodiversity and carbon stocks of Sri Lankan tropical forests are likely to increase with water-energy balance and improved soil conditions, and thus, studied forests could offset a substantial quantity of anthropogenic carbon emissions to achieve carbon neutrality which can have both regional and global significance if protected from anthropogenic disturbances.
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| 20. |
- Abbasi, Umar Aftab, et al.
(författare)
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Species α-diversity promotes but β-diversity restricts aboveground biomass in tropical forests, depending on stand structure and environmental factors
- 2022
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Ingår i: Journal of Forestry Research. - Göteborg : IVL Svenska Miljöinstitutet AB. - 1007-662X .- 1993-0607.
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Tidskriftsartikel (refereegranskat)abstract
- Forest plays a vital role in the global biogeochemical cycles through a high rate of carbon sequestration and harboring biodiversity. However, local species diversity is declining while also becoming increasingly homogenized across communities. Although effects of local biotic processes (e.g., species α-diversity and stand structural heterogeneity) and environmental factors on aboveground biomass (AGB) have been widely tested, there is a huge knowledge gap for the effect of regional biotic processes (i.e., taxonomic and functional β-diversity) in forests. Here, we hypothesized that regional and local environmental factors along with biotic processes jointly regulate AGB through species shifts in tropical forests.Using piecewise structural equation modeling (pSEM), we linked climatic water availability, soil fertility, stand structural heterogeneity (either tree DBH inequality, height inequality, or stand density), species α-diversity, taxonomic or functional β-diversity (and its two components; β-turnover and β-richness), and AGB across 189 inventory plots in tropical forests of Sri Lanka. Soil fertility and climatic water availability shaped local and regional biotic processes. Stand structural heterogeneity promoted species α-diversity but declined β-diversity (but increased β-taxonomic turnover). Species α-diversity and stand structural heterogeneity promoted AGB whereas taxonomic and functional β-diversity declined (but β-taxonomic turnover increased) AGB.The relationships of AGB with species α-diversity and β-diversity varied from significant to nonsignificant positive depending on the specific combinations of stand structural heterogeneity metrics used. This study shows that local biotic processes could increase AGB due to the local and regional niche complementarity effect whereas the regional biotic processes could restrict AGB due to the regional selection or functional redundancy effect under favorable environmental conditions. We argue that biotic homogenization, as well as drought conditions, may have strong divergent impacts on forest functions and that the impacts of tree diversity loss may greatly reduce carbon sequestration.
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| 21. |
- Ahmad, A, et al.
(författare)
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Requirements prioritization with respect to Geographically Distributed Stakeholders
- 2011
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Konferensbidrag (refereegranskat)abstract
- Requirements selection for software releases can play a vital role in the success of software product. This selection of requirements is done by different requirements prioritization techniques. This paper discusses limitations of these Requirements Prioritization Techniques (100$ Method and Binary Search Tree) with respect to Geographical Distribution of Stakeholders. We conducted two experiments, in this paper, in order to analyze the variations among the results of these Requirements Prioritization Techniques. This paper also discusses attributes that can affect the requirements prioritization when dealing with Geographically Distributed Stakeholders. We conducted first experiment with 100$ Dollar method and Binary Search Tree technique and second experiment has been conducted with modified 100$ Dollar method and Binary search tree technique. Results of these experiments have been discussed in this paper. This paper provides a framework that can be used to identify those requirements that can play an important role in a product success during distributed development.
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| 22. |
- Ahmad, Naveed, et al.
(författare)
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The nexus of csr and co-creation : A roadmap towards consumer loyalty
- 2021
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Ingår i: Sustainability (Switzerland). - : MDPI AG. - 2071-1050. ; 13:2
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Tidskriftsartikel (refereegranskat)abstract
- Corporate Social Responsibility (CSR) is regarded as an effort to be undertaken by the businesses to contribute towards society at large positively. The idea behind the concept of CSR is that businesses are required to pursue the notion of pro-social objectives along with economic objectives. Research has long established that corporate social responsibility, along with its philanthropic nature, can also produce extraordinary marketing results for businesses. The relationship between CSR and consumer loyalty is well acknowledged in extant literature. Likewise, involving consumers through co-creation in the product/service development process may provide an exciting experience to consumers, which is likely to influence their loyalty. With these arguments, the present research investigates the impact of CSR on consumer loyalty with the mediating role of co-creation in the banking sector of an emerging economy such as Pakistan. Structural equation modeling (SEM) is used for data analysis in the present study. The results validate that CSR improves consumer loyalty, and co-creation partially mediates this relationship. The results of the current survey will help banking institutions to identify how they can develop core strategic considerations based on CSR and co-creation.
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| 23. |
- Ali, Arshad, et al.
(författare)
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Big-sized trees and species-functional diversity pathways mediate divergent impacts of environmental factors on individual biomass variability in Sri Lankan tropical forests
- 2022
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Ingår i: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 315, s. 115177-115177
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we used the Partial Least Squares Structural Equation Models (PLS-SEMs), and other complementary analyses, on data from 189 tropical forest plots in Sri Lanka, to test the linkages amongst climate, soil, plot conditions, big-sized trees, species-functional diversity, and abiotic and biotic effects on individual biomass variability (BioVar). This study suggests that individual tree biomass variability (i.e., BioVar) should be considered for managing natural tropical forests in the context of the plant-plant interactions for species coexistence.
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| 24. |
- Ali, Arshad, et al.
(författare)
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Disentangling the effects of species diversity, and intraspecific and interspecific tree size variation on aboveground biomass in dry zone homegarden agroforestry systems
- 2017
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 598, s. 38-48
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Tidskriftsartikel (refereegranskat)abstract
- The biodiversity – aboveground biomass relationship has been intensively studied in recent decades. However, no consensus has been arrived to consider the interplay of species diversity, and intraspecific and interspecific tree size variation in driving aboveground biomass, after accounting for the effects of plot size heterogeneity, soil fertility and stand quality in natural forest including agroforests. We tested the full, partial and no mediations effects of species diversity, and intraspecific and interspecific tree size variation on aboveground biomass by employing structural equation models (SEMs) using data from 45 homegarden agroforestry systems in Sri Lanka. The full mediation effect of either species diversity or intraspecific and interspecific tree size variation was rejected, while the partial and no mediation effects were accepted. In the no mediation SEM, homegarden size had the strongest negative direct effect (? = ? 0.49) on aboveground biomass (R2 = 0.65), followed by strong positive direct effect of intraspecific tree size variation (? = 0.32), species diversity (? = 0.29) and interspecific tree size variation (? = 0.28). Soil fertility had a negative direct effect on interspecific tree size variation (? = ? 0.31). Stand quality had a significant positive total effect on aboveground biomass (? = 0.28), but homegarden size had a significant negative total effect (? = ? 0.62), while soil fertility had a non-significant total effect on aboveground biomass. Similar to the no mediation SEM, the partial mediation SEMs had explained almost similar variation in aboveground biomass because species diversity, and intraspecific and interspecific tree size variation had non-significant indirect effects on aboveground biomass via each other. Our results strongly suggest that a multilayered tree canopy structure, due to high intraspecific and interspecific tree size variation, increases light capture and efficient utilization of resources among component species, and hence, support the niche complementarity mechanism via plant-plant interactions.
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| 25. |
- Ali, Arshad, et al.
(författare)
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Individual tree size inequality enhances aboveground biomass in homegarden agroforestry systems in the dry zone of Sri Lanka
- 2017
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697. ; 575, s. 6-11
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Tidskriftsartikel (refereegranskat)abstract
- Individual tree size variation, which is generally quantified by variances in tree diameter at breast height (DBH) and height in isolation or conjunction, plays a central role in ecosystem functioning in both controlled and natural environments, including forests. However, none of the studies have been conducted in homegarden agroforestry systems. In this study, aboveground biomass, stand quality, cation exchange capacity (CEC), DBH variation, and species diversity were determined across 45 homegardens in the dry zone of Sri Lanka. We employed structural equation modeling (SEM) to test for the direct and indirect effects of stand quality and CEC, via tree size inequality and species diversity, on aboveground biomass. The SEM accounted for 26, 8, and 1% of the variation in aboveground biomass, species diversity and DBH variation, respectively. DBH variation had the strongest positive direct effect on aboveground biomass (β = 0.49), followed by the non-significant direct effect of species diversity (β = 0.17), stand quality (β = 0.17) and CEC (β = − 0.05). There were non-significant direct effects of CEC and stand quality on DBH variation and species diversity. Stand quality and CEC had also non-significant indirect effects, via DBH variation and species diversity, on aboveground biomass. Our study revealed that aboveground biomass substantially increased with individual tree size variation only, which supports the niche complementarity mechanism. However, aboveground biomass was not considerably increased with species diversity, stand quality and soil fertility, which might be attributable to the adaptation of certain productive species to the local site conditions. Stand structure shaped by few productive species or independent of species diversity is a main determinant for the variation in aboveground biomass in the studied homegardens. Maintaining stand structure through management practices could be an effective approach for enhancing aboveground biomass in these dry zone homegarden agroforestry systems.
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| 26. |
- Ali, Arshad, et al.
(författare)
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Individual tree size inequality enhances aboveground biomass in homegarden agroforestry systems in the dry zone of Sri Lanka
- 2016
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Ingår i: Science of the Total Environment. - 0048-9697 .- 1879-1026. ; 575, s. 6-11
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Tidskriftsartikel (refereegranskat)abstract
- Individual tree size variation, which is generally quantified by variances in tree diameter at breast height (DBH) and height in isolation or conjunction, plays a central role in ecosystem functioning in both controlled and natural environments, including forests. However, none of the studies have been conducted in homegarden agroforestry systems. In this study, aboveground biomass, stand quality, cation exchange capacity (CEC), DBH variation, and species diversity were determined across 45 homegardens in the dry zone of Sri Lanka. We employed structural equation modeling (SEM) to test for the direct and indirect effects of stand quality and CEC, via tree size inequality and species diversity, on aboveground biomass. The SEM accounted for 26, 8, and 1% of the variation in aboveground biomass, species diversity and DBH variation, respectively. DBH variation had the strongest positive direct effect on aboveground biomass (β = 0.49), followed by the non-significant direct effect of species diversity (β = 0.17), stand quality (β = 0.17) and CEC (β = − 0.05). There were non-significant direct effects of CEC and stand quality on DBH variation and species diversity. Stand quality and CEC had also non-significant indirect effects, via DBH variation and species diversity, on aboveground biomass. Our study revealed that aboveground biomass substantially increased with individual tree size variation only, which supports the niche complementarity mechanism. However, aboveground biomass was not considerably increased with species diversity, stand quality and soil fertility, which might be attributable to the adaptation of certain productive species to the local site conditions. Stand structure shaped by few productive species or independent of species diversity is a main determinant for the variation in aboveground biomass in the studied homegardens. Maintaining stand structure through management practices could be an effective approach for enhancing aboveground biomass in these dry zone homegarden agroforestry systems.
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| 27. |
- Ali, Arshad, et al.
(författare)
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Wood density is a sustainability indicator for the management of dry zone homegarden agroforests: Evidences from biodiversity–ecosystem function relationships
- 2019
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Ingår i: Ecological Indicators. - : Elsevier BV. - 1470-160X. ; 105, s. 474-482
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies have advanced our understanding regarding the niche complementarity and mass ratio effects on the ecosystem function, in both natural and experimental systems. However, biodiversity–ecosystem function (BEF) relationships may be fundamentally different across dense-wooded and light-wooded species, as they are clustered at two opposite extremes of the wood economics spectrum. Here we analyzed BEF relationships through mediations of functional dominance (i.e. community-weighted mean, CWM) and functional divergence (FDvar) of plant maximum height (H) while accounting for the effects of other characteristics of homegardens, across dense-wooded, light-wooded and all species, by using structural equation modelling (SEM) on 45 homegarden agroforestry systems in the dry zone of Sri Lanka. The dense-wooded SEM accounted for 69% variation in aboveground biomass through significant positive direct effects of CWM H (β = 0.51) and FDvar H (β = 0.20), and indirect effect of species diversity via FDvar H on aboveground biomass (β = 0.12). Although the light-wooded SEM accounted for 19% variation in aboveground biomass, the BEF relationships were non-significant. Regardless of SEMs, FDvar H but not CWM H was significantly positively related to species diversity. None of the BEF relationships was statistically significant when dense-wooded and light-wooded species were mixed. From a theoretical aspect, these positive BEF relationships are driven by both dominant and complementarity dense-wooded species. From a practical aspect, the positive BEF relationships support the feasibility of UN Reducing Emissions from Deforestation and Forest Degradation (REDD+) initiative in studied agroforests, which aims to enhance carbon storage in aboveground biomass while conserving biodiversity. Hence, this study suggests that wood density is a potential sustainability indicator for better management of agroforest-ecosystem while driving positive BEF relationships.
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| 28. |
- Arshad, F., et al.
(författare)
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Beam-width agile antenna for 5g mmw applications
- 2020
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Ingår i: Proceedings 2020 International Conference on UK-China Emerging Technologies, UCET 2020. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- In this communication, a beam width reconfigurable antenna with the parasitic elements is presented for 5G applications. The proposed antenna consists of an inset fed circular patch (driven element). To enhance the impedance matching a-35° rotated slot is inserted in the circular patch. Four parasitic arcs are placed in the close proximity of the driven element. In first case three pin-diodes are loaded among the arcs to tune the mutual coupling between arcs and driven element. In the second case pin-diodes are replaced with GeTe material based strips for reconfiguration purposes. This design can operate between 27.2-32 GHz with a peak realized gain of 9.1 dBi. In the first case, beamwidth can be enlarged from 58° to 121.3o. In the second case, beamwidth can be vary from 75° to 128.7°. In both cases beam is also steered.
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| 29. |
- Arshad, Farzana, et al.
(författare)
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Compact beam-switchable antenna for mm-wave 5G handheld devices
- 2021
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Ingår i: IET Microwaves, Antennas & Propagation. - : WILEY. - 1751-8725 .- 1751-8733. ; 15:7, s. 778-787
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Tidskriftsartikel (refereegranskat)abstract
- An electronically beam-steerable antenna (BSA) is envisioned. The presented BSA is a possible solution to overthrow the limitations inherent to phased antenna arrays. The design consists of a gap coupling inset feed rectangular patch (driven element) and 3 x 1 passive parasitic patches deployed on both sides of the driven patch. Prototype having 20 x 20 mm dimensions is printed on Rogers(R) RT/duroid(R)5870. Four switches are used to load the reactive impedance on parasitic patches, which in turn, change the phases of surface current on parasitic elements and the driven element. Based on the different ON and OFF configuration of switches in parasitic array elements, the main beam is steered along with different directions. The simulated results show that the design can operate between 26.8 and 30.3 GHz a wide impedance bandwidth |S-11|< -10 dB (12.5%) with a peak gain of 8.9 dBi and wide 3-dB scanning angle that is, -37 degrees to 156 degrees in the azimuth plane. The exhibited performance of BSA with favourable characteristics, such as wideband, adequate gain, wide-angle beam switching, and low profile renders the BSA a good candidate for 5G millimetre wave handheld devices. Moreover, to corroborate the performance, the design is fabricated, and experimental measurements were performed. Congruence is observed between the experimentally measured and computationally simulated results. The simulated results of spherical coverage analysis of BSA with the integration of smartphone form factor are also presented.
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| 30. |
- Arshad, F., et al.
(författare)
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Polorization Reconfigurable MIMO System for 5G MMW Applications
- 2020
-
Ingår i: Proceedings - 2020 23rd IEEE International Multi-Topic Conference, INMIC 2020. - : Institute of Electrical and Electronics Engineers Inc..
-
Konferensbidrag (refereegranskat)abstract
- This paper presents a novel electronically polarization reconfigurable 2 port multi input multi output (MIMO) for millimeter wave (MMW) fifth-generation (5G) wireless communications. The design consists of slotted circular patch. A semicircle and open-ended T-shaped arcs are inserted in circular patch to achieve the circular polarization. Furthermore in order to enhance the gain 2 element array is designed. Two pin-diodes are inserted in antenna array for polarization diversity. The design is extended to two ports MIMO. Port isolation is enhanced between the ports using defected ground structure (DGS). The vertical and horizontal slots are inserted in the ground to enhance the port isolation. The presented design covers dual frequency band that 24.0-25.3 and 27.3-28.7 GHz band. The 27.3-28.7 GHz band is considered for investigation of all parameters. The simulated peak gain is 9.99 dBi. The axial ratio (AR) below-3dB is achieved for whole operating band of proposed design. The MIMO performance parameters like transmission coefficient, Envelop correlation coefficient (ECC), and diversity gain (DG) are also investigated.
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| 31. |
- Arshad, Nasima, et al.
(författare)
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Synthesis, X-ray, Hirshfeld surface analysis, exploration of DNA binding, urease enzyme inhibition and anticancer activities of novel adamantane-naphthyl thiourea conjugate
- 2021
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Ingår i: Bioorganic chemistry (Print). - : Elsevier. - 0045-2068. ; 109
-
Tidskriftsartikel (refereegranskat)abstract
- 1-(adamantane-1-carbonyl-3-(1-naphthyl)) thiourea (C22H24N2OS (4), was synthesized by the reaction of freshly prepared adamantane-1-carbonyl chloride from corresponding acid (3) with ammonium thiocyanate in 1:1 M ratio in dry acetone to afford the adamantane-1-carbonyl isothiocyanate (2) in situ followed by treatment with 1-naphthyl amine (3). The structure was established by elemental analyses, FTIR, H-1, C-13 NMR and mass spectroscopy. The molecular and crystal structure were determined by single crystal X-ray analysis. It belongs to triclinic system P - 1 space group with a = 6.7832(5) angstrom, b = 11.1810(8) angstrom, c = 13.6660(10) angstrom, alpha = 105.941(6)degrees, beta = 103.730(6)degrees, gamma = 104.562(6)degrees, Z = 2, V = 910.82(11) angstrom(3). The naphthyl group is almost planar. In the crystal structure, intermolecular C-H center dot center dot center dot O hydrogen bonds link the molecules into centrosymmetric dimers, enclosing R-2(2)(14) ring motifs, while the intramolecular N-H center dot center dot center dot O hydrogen bonds enclose S(6) ring motifs, in which they may be effective in the stabilization of the structure. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H center dot center dot center dot H (59.3%), H center dot center dot center dot C/C center dot center dot center dot H (19.8%) and H center dot center dot center dot S/S center dot center dot center dot H (10.1%) interactions. Hydrogen bonding and van der Waals interactions are the dominant interactions in the crystal packing. DFT, molecular docking and urease inhibition studies revealed stability and electron withdrawing nature of 4 as compared to DNA base pairs and residues of urease. The DNA binding results from docking, UV-visible spectroscopy, and viscosity studies indicated significant binding of 4 with the DNA via intercalation and groove binding. Further investigation of the compound was done on hepatocellular carcinoma; Huh-7 cell line as well as normal human embryonic kidney; Hek-293 cell line. The compound showed significant cytotoxic activity against Huh-7 cells in comparison to normal Hek-293 cells indicating selective cytotoxicity towards cancer cells.
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| 32. |
- Biurrun, Idoia, et al.
(författare)
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Benchmarking plant diversity of Palaearctic grasslands and other open habitats
- 2021
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Ingår i: Journal of Vegetation Science. - Oxford : John Wiley & Sons. - 1100-9233 .- 1654-1103. ; 32:4
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Tidskriftsartikel (refereegranskat)abstract
- Journal of Vegetation Science published by John Wiley & Sons Ltd on behalf of International Association for Vegetation Science.Aims: Understanding fine-grain diversity patterns across large spatial extents is fundamental for macroecological research and biodiversity conservation. Using the GrassPlot database, we provide benchmarks of fine-grain richness values of Palaearctic open habitats for vascular plants, bryophytes, lichens and complete vegetation (i.e., the sum of the former three groups). Location: Palaearctic biogeographic realm. Methods: We used 126,524 plots of eight standard grain sizes from the GrassPlot database: 0.0001, 0.001, 0.01, 0.1, 1, 10, 100 and 1,000 m2 and calculated the mean richness and standard deviations, as well as maximum, minimum, median, and first and third quartiles for each combination of grain size, taxonomic group, biome, region, vegetation type and phytosociological class. Results: Patterns of plant diversity in vegetation types and biomes differ across grain sizes and taxonomic groups. Overall, secondary (mostly semi-natural) grasslands and natural grasslands are the richest vegetation type. The open-access file ”GrassPlot Diversity Benchmarks” and the web tool “GrassPlot Diversity Explorer” are now available online (https://edgg.org/databases/GrasslandDiversityExplorer) and provide more insights into species richness patterns in the Palaearctic open habitats. Conclusions: The GrassPlot Diversity Benchmarks provide high-quality data on species richness in open habitat types across the Palaearctic. These benchmark data can be used in vegetation ecology, macroecology, biodiversity conservation and data quality checking. While the amount of data in the underlying GrassPlot database and their spatial coverage are smaller than in other extensive vegetation-plot databases, species recordings in GrassPlot are on average more complete, making it a valuable complementary data source in macroecology. © 2021 The Authors.
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| 33. |
- Halle-Smith, James M., et al.
(författare)
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Perioperative interventions to reduce pancreatic fistula following pancreatoduodenectomy : meta-analysis
- 2022
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Ingår i: The British journal of surgery. - : Oxford University Press (OUP). - 1365-2168 .- 0007-1323. ; 109:9, s. 812-821
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Data on interventions to reduce postoperative pancreatic fistula (POPF) following pancreatoduodenectomy (PD) are conflicting. The aim of this study was to assimilate data from RCTs. METHODS: MEDLINE and Embase databases were searched systematically for RCTs evaluating interventions to reduce all grades of POPF or clinically relevant (CR) POPF after PD. Meta-analysis was undertaken for interventions investigated in multiple studies. A post hoc analysis of negative RCTs assessed whether these had appropriate statistical power. RESULTS: Among 22 interventions (7512 patients, 55 studies), 12 were assessed by multiple studies, and subjected to meta-analysis. Of these, external pancreatic duct drainage was the only intervention associated with reduced rates of both CR-POPF (odds ratio (OR) 0.40, 95 per cent c.i. 0.20 to 0.80) and all-POPF (OR 0.42, 0.25 to 0.70). Ulinastatin was associated with reduced rates of CR-POPF (OR 0.24, 0.06 to 0.93). Invagination (versus duct-to-mucosa) pancreatojejunostomy was associated with reduced rates of all-POPF (OR 0.60, 0.40 to 0.90). Most negative RCTs were found to be underpowered, with post hoc power calculations indicating that interventions would need to reduce the POPF rate to 1 per cent or less in order to achieve 80 per cent power in 16 of 34 (all-POPF) and 19 of 25 (CR-POPF) studies respectively. CONCLUSION: This meta-analysis supports a role for several interventions to reduce POPF after PD. RCTs in this field were often relatively small and underpowered, especially those evaluating CR-POPF.
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| 34. |
- Isikman, Arif Onder, 1988, et al.
(författare)
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Joint phase noise estimation and data detection in coded multi-input-multi-output systems
- 2014
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Ingår i: IET Communications. - : Institution of Engineering and Technology (IET). - 1751-8628 .- 1751-8636. ; 8:7, s. 981-989
-
Tidskriftsartikel (refereegranskat)abstract
- The problem of joint oscillator phase noise (PHN) estimation and data detection for multi-input multi-output (MIMO) systems using bit-interleaved-coded modulation is analysed. A new MIMO receiver that iterates between the estimator and the detector, based on the expectation-maximisation (EM) framework, is proposed. It is shown that at high signal-to-noise ratios, a maximum a posteriori (MAP) estimator can be used to carry out the maximisation step of the EM algorithm. Moreover, to reduce the computational complexity of the proposed EM algorithm, a soft decision-directed extended Kalman filter-smoother (EKFS) is applied instead of the MAP estimator to track the PHN parameters. The numerical results show that by combining the proposed EKFS-based approach with an iterative detector that employs low-density parity check codes, PHN can be accurately tracked. The simulations also demonstrate that compared to the existing algorithms, the proposed iterative receiver can significantly enhance the performance of MIMO systems in the presence of PHN.
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| 35. |
- Jucker, Tommaso, et al.
(författare)
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Tallo: A global tree allometry and crown architecture database
- 2022
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 28:17, s. 5254-5268
-
Tidskriftsartikel (refereegranskat)abstract
- Data capturing multiple axes of tree size and shape, such as a tree's stem diameter, height and crown size, underpin a wide range of ecological research—from developing and testing theory on forest structure and dynamics, to estimating forest carbon stocks and their uncertainties, and integrating remote sensing imagery into forest monitoring programmes. However, these data can be surprisingly hard to come by, particularly for certain regions of the world and for specific taxonomic groups, posing a real barrier to progress in these fields.To overcome this challenge, we developed the Tallo database, a collection of 498,838 georeferenced and taxonomically standardized records of individual trees for which stem diameter, height and/or crown radius have been measured. These data were collected at 61,856 globally distributed sites, spanning all major forested and non-forested biomes. The majority of trees in the database are identified to species (88%), and collectively Tallo includes data for 5163 species distributed across 1453 genera and 187 plant families. The database is publicly archived under a CC-BY 4.0 licence and can be access from: https://doi.org/10.5281/zenodo.6637599.To demonstrate its value, here we present three case studies that highlight how the Tallo database can be used to address a range of theoretical and applied questions in ecology—from testing the predictions of metabolic scaling theory, to exploring the limits of tree allometric plasticity along environmental gradients and modelling global variation in maximum attainable tree height. In doing so, we provide a key resource for field ecologists, remote sensing researchers and the modelling community working together to better understand the role that trees play in regulating the terrestrial carbon cycle.
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| 36. |
- Kalaria, Raj, et al.
(författare)
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The 2022 symposium on dementia and brain aging in low- and middle-income countries: Highlights on research, diagnosis, care, and impact.
- 2024
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Ingår i: Alzheimer's & dementia : the journal of the Alzheimer's Association. - 1552-5279.
-
Tidskriftsartikel (refereegranskat)abstract
- Two of every three persons living with dementia reside in low- and middle-income countries (LMICs). The projected increase in global dementia rates is expected to affect LMICs disproportionately. However, the majority of global dementia care costs occur in high-income countries (HICs), with dementia research predominantly focusing on HICs. This imbalance necessitates LMIC-focused research to ensure that characterization of dementia accurately reflects the involvement and specificities of diverse populations. Development of effective preventive, diagnostic, and therapeutic approaches for dementia in LMICs requires targeted, personalized, and harmonized efforts. Our article represents timely discussions at the 2022 Symposium on Dementia and Brain Aging in LMICs that identified the foremost opportunities to advance dementia research, differential diagnosis, use of neuropsychometric tools, awareness, and treatment options. We highlight key topics discussed at the meeting and provide future recommendations to foster a more equitable landscape for dementia prevention, diagnosis, care, policy, and management in LMICs. HIGHLIGHTS: Two-thirds of persons with dementia live in LMICs, yet research and costs are skewed toward HICs. LMICs expect dementia prevalence to more than double, accompanied by socioeconomic disparities. The 2022 Symposium on Dementia in LMICs addressed advances in research, diagnosis, prevention, and policy. The Nairobi Declaration urges global action to enhance dementia outcomes in LMICs.
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| 37. |
- Khan, Munema, et al.
(författare)
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Jejunal diverticulosis presenting as intestinal obstruction-A case report of a rare association
- 2023
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Ingår i: Clinical Case Reports. - : Wiley. - 2050-0904. ; 11:3
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Tidskriftsartikel (refereegranskat)abstract
- Jejunal diverticula are rare medical conditions with an incidence of 0.3%-2.5%, mostly discovered perioperatively. Our patient, 60 years old female, presented in an emergency with complaints of constipation, vomiting, abdominal pain, and distension. On examination, her abdomen was markedly distended with generalized tenderness. An erect abdominal X-ray revealed multiple air-fluid levels, which suggests small bowel obstruction. A diagnosis of jejunal diverticula was made on exploratory laparotomy. No evidence of granuloma or malignancy was seen on histopathological examination. Segmental resection of the affected jejunum was carried out, followed by end-to-end primary anastomosis. The patient was discharged on postoperative Day 6 with complete recovery at 2 weeks follow-up visit.
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| 38. |
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| 39. |
- Kocarnik, J. M., et al.
(författare)
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Cancer Incidence, Mortality, Years of Life Lost, Years Lived With Disability, and Disability-Adjusted Life Years for 29 Cancer Groups From 2010 to 2019 A Systematic Analysis for the Global Burden of Disease Study 2019
- 2022
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Ingår i: Jama Oncology. - : American Medical Association (AMA). - 2374-2437 .- 2374-2445. ; 8:3, s. 420-488
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Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE The Global Burden of Diseases, Injuries, and Risk Factors Study 2019 (GBD 2019) provided systematic estimates of incidence, morbidity, and mortality to inform local and international efforts toward reducing cancer burden. OBJECTIVE To estimate cancer burden and trends globally for 204 countries and territories and by Sociodemographic Index (SDI) quintiles from 2010 to 2019. EVIDENCE REVIEW The GBD 2019 estimation methods were used to describe cancer incidence, mortality, years lived with disability, years of life lost, and disability-adjusted life years (DALYs) in 2019 and over the past decade. Estimates are also provided by quintiles of the SDI, a composite measure of educational attainment, income per capita, and total fertility rate for those younger than 25 years. Estimates include 95% uncertainty intervals (UIs). FINDINGS In 2019, there were an estimated 23.6 million (95% UI, 22.2-24.9 million) new cancer cases (17.2 million when excluding nonmelanoma skin cancer) and 10.0 million (95% UI, 9.36-10.6 million) cancer deaths globally, with an estimated 250 million (235-264 million) DALYs due to cancer. Since 2010, these represented a 26.3%(95% UI, 20.3%-32.3%) increase in new cases, a 20.9%(95% UI, 14.2%-27.6%) increase in deaths, and a 16.0% (95% UI, 9.3%-22.8%) increase in DALYs. Among 22 groups of diseases and injuries in the GBD 2019 study, cancer was second only to cardiovascular diseases for the number of deaths, years of life lost, and DALYs globally in 2019. Cancer burden differed across SDI quintiles. The proportion of years lived with disability that contributed to DALYs increased with SDI, ranging from 1.4%(1.1%-1.8%) in the low SDI quintile to 5.7%(4.2%-7.1%) in the high SDI quintile. While the high SDI quintile had the highest number of new cases in 2019, the middle SDI quintile had the highest number of cancer deaths and YDALYs. From 2010 to 2019, the largest percentage increase in the numbers of cases and deaths occurred in the low and low-middle SDI quintiles. CONCLUSIONS AND RELEVANCE The results of this systematic analysis suggest that the global burden of cancer is substantial and growing, with burden differing by SDI. These results provide comprehensive and comparable estimates that can potentially inform efforts toward equitable cancer control around the world.
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| 40. |
- Mattsson, Eskil, et al.
(författare)
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Topmost trees and foremost species underlie tropical forest structure, diversity and biomass through opposing mechanisms
- 2020
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 473
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Tidskriftsartikel (refereegranskat)abstract
- Tropical forests play a main role in the global carbon cycle due to their higher exchange capacity of carbon dioxide with the atmosphere than any other forest type on the Earth. In this study, we aimed to explore the relative importance of foremost species and topmost trees in shaping forest structure, diversity and biomass in natural tropical forests. We hypothesized that topmost trees promote but foremost species decline tropical forest structure, diversity and biomass in a changing environment (i.e. the ‘tree overtopping hypothesis’). We formulated three questions to address the proposed hypothesis: (1) Are forest structure, diversity and biomass affected by both foremost species and topmost trees, and what is the magnitude and direction of each relative effect? (2) Are foremost species and topmost trees influenced similarly by multiple environmental factors? (3) How do foremost species and topmost trees mediate the feedbacks of forest structure, diversity and biomass to environmental factors? Using 189 plots data from Sri Lanka, we quantified 16 environmental (9 climate and 7 soil) factors, two indices of the topmost trees (i.e. top 1% large-diameter, and tall-stature) and their combination, four indices of foremost species (i.e. top 1% species' importance value index or each of its three components including either relative basal area, relative frequency or relative density), rarefied species richness, and stand density. We used structural equation modeling to test the proposed hypothesis. Strong positive effects of topmost trees whereas negative to negligible positive effects of foremost species shaped tropical forest structure, diversity and biomass through opposing mechanisms, i.e., the promoting part of big trees and suppressing part of dominant species, respectively. Moreover, forest structure promoted biomass directly and indirectly via forest diversity. Environmental factors (i.e. high climatic water and low soil fertility) increased forest structure, diversity and biomass indirectly via topmost trees but decreased via foremost species. The main novelty or contribution of this study determines that the adverse effects of few foremost (i.e. dominant or abundant) species shaped forest structure, diversity and biomass in tropical forests when simultaneously considered the positive effects of topmost trees. Hence, encouraging topmost trees while managing foremost species might necessarily increase complementarity resource-use within a forest community, leading to positive forest diversity – structure – biomass relationships. We argue that both topmost trees and foremost species might have important influences on forest carbon stock in the context of global climate change.
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| 41. |
- Mehrpouyan, Hani, 1981, et al.
(författare)
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Joint Estimation of Channel and Oscillator Phase Noise in MIMO Systems
- 2012
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Ingår i: IEEE Transactions on Signal Processing. - 1941-0476 .- 1053-587X. ; 60:9, s. 4790-4807
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Tidskriftsartikel (refereegranskat)abstract
- Oscillator phase noise limits the performance of high speed communication systems since it results in timevarying channels and rotation of the signal constellation from symbol to symbol. In this paper, joint estimation ofchannel gains and Wiener phase noise in multi-input multi-output (MIMO) systems is analyzed. The signal modelfor the estimation problem is outlined in detail and new expressions for the Cram´er-Rao lower bounds (CRLBs) forthe multi-parameter estimation problem are derived. A data-aided least-squares (LS) estimator for jointly obtainingthe channel gains and phase noise parameters is derived. Next, a decision-directed weighted least-squares (WLS)estimator is proposed, where pilots and estimated data symbols are employed to track the time-varying phase noiseparameters over a frame. In order to reduce the overhead and delay associated with the estimation process, anew decision-directed extended Kalman filter (EKF) is proposed for tracking the MIMO phase noise throughouta frame. Numerical results show that the proposed LS, WLS, and EKF estimators’ performances are close to theCRLB. Finally, simulation results demonstrate that by employing the proposed channel and time-varying phase noiseestimators the bit-error rate (BER) performance of a MIMO system can be significantly improved.
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| 42. |
- Mehrpouyan, Hani, 1981, et al.
(författare)
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Time-varying phase noise and channel estimation in MIMO systems
- 2012
-
Ingår i: IEEE Workshop on Signal Processing Advances in Wireless Communications, SPAWC. - 9781467309707 ; , s. 560-564
-
Konferensbidrag (refereegranskat)abstract
- Performance of high speed communication systems is negatively affected by oscillator phase noise (PN). In this paper joint estimation of channel gains and Wiener PN in multi-input multi-output (MIMO) systems is analyzed. The signal model for the estimation problem is outlined in detail. In order to reduce overhead, a low complexity data-aided least-squares (LS) estimator for jointly obtaining the channel gains and PN parameters is derived. In order to track PN processes over a frame, a new decision-directed extended Kalman filter (EKF) is proposed. Numerical results show that the proposed LS and EKF based PN estimator performances are close to the CRLB and simulation results indicate that by employing the proposed estimators the bit-error rate (BER) performance of a MIMO system can be significantly improved in the presence of PN.
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| 43. |
- Mushtaq, Iram, et al.
(författare)
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N-acetyl cysteine, selenium, and ascorbic acid rescue diabetic cardiac hypertrophy via mitochondrial-associated redox regulators
- 2021
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Ingår i: Molecules. - : MDPI AG. - 1420-3049. ; 26:23
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Tidskriftsartikel (refereegranskat)abstract
- Metabolic disorders often lead to cardiac complications. Metabolic deregulations during diabetic conditions are linked to mitochondrial dysfunctions, which are the key contributing factors in cardiac hypertrophy. However, the underlying mechanisms involved in diabetes-induced cardiac hypertrophy are poorly understood. In the current study, we initially established a diabetic rat model by alloxan-administration, which was validated by peripheral glucose measurement. Diabetic rats displayed myocardial stiffness and fibrosis, changes in heart weight/body weight, heart weight/tibia length ratios, and enhanced size of myocytes, which altogether demonstrated the establishment of diabetic cardiac hypertrophy (DCH). Furthermore, we examined the expression of genes associated with mitochondrial signaling impairment. Our data show that the expression of PGC-1α, cytochrome c, MFN-2, and Drp-1 was deregulated. Mitochondrial-signaling impairment was further validated by redox-system dysregulation, which showed a significant increase in ROS and thiobarbituric acid reactive substances, both in serum and heart tissue, whereas the superoxide dismutase, catalase, and glutathione levels were decreased. Additionally, the expression levels of pro-apoptotic gene PUMA and stress marker GATA-4 genes were elevated, whereas ARC, PPARα, and Bcl-2 expression levels were decreased in the heart tissues of diabetic rats. Importantly, these alloxan-induced impairments were rescued by N-acetyl cysteine, ascorbic acid, and selenium treatment. This was demonstrated by the amelioration of myocardial stiffness, fibrosis, mitochondrial gene expression, lipid profile, restoration of myocyte size, reduced oxidative stress, and the activation of enzymes associated with antioxidant activities. Altogether, these data indicate that the improvement of mitochondrial dysfunction by protective agents such as N-acetyl cysteine, selenium, and ascorbic acid could rescue diabetes-associated cardiac complications, including DCH.
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| 44. |
- Nasir, Ali Arshad, et al.
(författare)
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Estimation of Synchronization Parameters in AF Cooperative Networks
- 2012
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Ingår i: IEEE International Conference on Communications. - 1550-3607. - 9781457720529 ; , s. 3713-3717
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Konferensbidrag (refereegranskat)abstract
- In cooperative networks, multiple carrier frequencyoffsets (MCFOs) and multiple timing offsets (MTOs) originate due to multiple distributed nodes. In this paper, algorithms for joint estimation of these parameters and channels in amplify-and-forward (AF) relaying networks are proposed. A new training model and transceiver structure at the relays for achieving synchronization throughout the network is devised. New exact closed-form expressions for the Cram´er-Rao lower bounds (CRLBs) for the multi-parameter estimation problem are derived. An estimation method is proposed for jointly estimating MCFOs, MTOs, and channel gains at the destination based on space-alternating generalized expectation maximization (SAGE) and compared to a computationally-intensiveleast squares (LS) approach. The proposed estimator’s performance is shown to be close to the CRLB at mid-to-high signal-to-noise ratio (SNR) resulting in significant cooperative performance gains in the presence of practical impairments.
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| 45. |
- Nasir, Ali Arshad, et al.
(författare)
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Fractional Time Exploitation for Serving IoT Users with Guaranteed QoS by 5G Spectrum
- 2018
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Ingår i: IEEE Communications Magazine. - : Institute of Electrical and Electronics Engineers Inc.. - 0163-6804 .- 1558-1896. ; 56:10, s. 128-133
-
Tidskriftsartikel (refereegranskat)abstract
- It is generally understood that forthcoming 5G communication technologies such as full duplex (FD), massive multiple-input multiple-output (MIMO), non-orthogonal multiple access (NOMA), and simultaneous wireless information and power transfer (SWIPT) aim at the maximal use of communication spectrum to provide a new experience of service for users. FD provides simultaneous signal transmission and reception over the same frequency band. Massive MIMO uses massive numbers of antennas to provide high throughput connectivity for users. NOMA improves network throughput by allowing some users to access information intended for other users. SWIPT provides simultaneous information and power transfer. However, it is still very challenging to utilize these spectrum exploitation technologies to secure the needed quality of service for users in the age of the Internet of Things. In FD, the signal transmission interference to signal reception, even after analog and digital self-interference cancellation, is considerable, which downgrades both transmission and reception throughput. To maintain the favored channel characteristics, massive MIMO means to serve a few users per time unit only. In NOMA, the users' throughput is improved by compromising communication privacy. Information and power transmissions head to conflicting targets that are difficult to achieve simultaneously with SWIPT. This article introduces a new technique, called the fractional-time approach, which ensures guaranteed and better transmission and reception throughput without the need for complex FD, enables serving a massive number of users in a massive MIMO system, provides guaranteed users' throughput without security compromise as in NOMA, and delivers high volumes of both information and power transfer within a time unit. © 1979-2012 IEEE.
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| 46. |
- Nasir, Ali Arshad, et al.
(författare)
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Timing and Carrier Synchronization with Channel Estimation in Multi-Relay Cooperative Networks
- 2012
-
Ingår i: IEEE Transactions on Signal Processing. - 1941-0476 .- 1053-587X. ; 60:2, s. 793-811
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Tidskriftsartikel (refereegranskat)abstract
- Multiple distributed nodes in cooperative networksgenerally are subject to multiple carrier frequency offsets (MCFOs)and multiple timing offsets (MTOs), which result in time varying channels and erroneous decoding. This paper seeks to develop estimation and detection algorithms that enable cooperative communications for both decode-and-forward (DF) and amplify-and-forward (AF) relaying networks in the presence of MCFOs, MTOs, and unknown channel gains. A novel transceiver structure at the relays for achieving synchronization in AF-relaying networks is proposed. New exact closed-form expressions for the Cramér-Rao lower bounds (CRLBs) for the multi-parameter estimation problem are derived. Next, two iterative algorithms based on the expectation conditional maximization (ECM) and space-alternating generalized expectation-maximization (SAGE) algorithms are proposed for jointly estimating MCFOs, MTOs, and channel gains at the destination. Though the global convergence of the proposed ECM and SAGE estimators cannot be shown analytically, numerical simulations indicate that through appropriate initialization the proposed algorithms can estimate channel and synchronization impairments in a few iterations. Finally, a maximum likelihood (ML) decoder is devised for decoding the received signal at the destination in the presence of MCFOs and MTOs. Simulation results show that through the application of the proposed estimation and decoding methods, cooperative systems result in significant performance gains even in presence of impairments.
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| 47. |
- Pande, Rupaly, et al.
(författare)
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Can trainees safely perform pancreatoenteric anastomosis? A systematic review, meta-analysis, and risk-adjusted analysis of postoperative pancreatic fistula
- 2022
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Ingår i: Surgery (United States). - : Elsevier BV. - 0039-6060. ; 172:1, s. 319-328
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Forskningsöversikt (refereegranskat)abstract
- Background: The complexity of pancreaticoduodenectomy and fear of morbidity, particularly postoperative pancreatic fistula, can be a barrier to surgical trainees gaining operative experience. This meta-analysis sought to compare the postoperative pancreatic fistula rate after pancreatoenteric anastomosis by trainees or established surgeons. Methods: A systematic review of the literature was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, with differences in postoperative pancreatic fistula rates after pancreatoenteric anastomosis between trainee-led versus consultant/attending surgeons pooled using meta-analysis. Variation in rates of postoperative pancreatic fistula was further explored using risk-adjusted outcomes using published risk scores and cumulative sum control chart analysis in a retrospective cohort. Results: Across 14 cohorts included in the meta-analysis, trainees tended toward a lower but nonsignificant rate of all postoperative pancreatic fistula (odds ratio: 0.77, P =.45) and clinically relevant postoperative pancreatic fistula (odds ratio: 0.69, P =.37). However, there was evidence of case selection, with trainees being less likely to operate on patients with a pancreatic duct width <3 mm (odds ratio: 0.45, P =.05). Similarly, analysis of a retrospective cohort (N = 756 cases) found patients operated by trainees to have significantly lower predicted all postoperative pancreatic fistula (median: 20 vs 26%, P <.001) and clinically relevant postoperative pancreatic fistula (7 vs 9%, P =.020) rates than consultant/attending surgeons, based on preoperative risk scores. After adjusting for this on multivariable analysis, the risks of all postoperative pancreatic fistula (odds ratio: 1.18, P =.604) and clinically relevant postoperative pancreatic fistula (odds ratio: 0.85, P =.693) remained similar after pancreatoenteric anastomosis by trainees or consultant/attending surgeons. Conclusion: Pancreatoenteric anastomosis, when performed by trainees, is associated with acceptable outcomes. There is evidence of case selection among patients undergoing surgery by trainees; hence, risk adjustment provides a critical tool for the objective evaluation of performance.
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| 48. |
- Pande, Rupaly, et al.
(författare)
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External validation of postoperative pancreatic fistula prediction scores in pancreatoduodenectomy : a systematic review and meta-analysis
- 2022
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Ingår i: HPB. - : Elsevier BV. - 1365-182X. ; 24:3, s. 287-298
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Forskningsöversikt (refereegranskat)abstract
- Background: Multiple risk scores claim to predict the probability of postoperative pancreatic fistula (POPF) after pancreatoduodenectomy. It is unclear which scores have undergone external validation and are the most accurate. The aim of this study was to identify risk scores for POPF, and assess the clinical validity of these scores. Methods: Areas under receiving operator characteristic curve (AUROCs) were extracted from studies that performed external validation of POPF risk scores. These were pooled for each risk score, using intercept-only random-effects meta-regression models. Results: Systematic review identified 34 risk scores, of which six had been subjected to external validation, and so included in the meta-analysis, (Tokyo (N=2 validation studies), Birmingham (N=5), FRS (N=19), a-FRS (N=12), m-FRS (N=3) and ua-FRS (N=3) scores). Overall predictive accuracies were similar for all six scores, with pooled AUROCs of 0.61, 0.70, 0.71, 0.70, 0.70 and 0.72, respectively. Considerably heterogeneity was observed, with I2 statistics ranging from 52.1-88.6%. Conclusion: Most risk scores lack external validation; where this was performed, risk scores were found to have limited predictive accuracy. Consensus is needed for which score to use in clinical practice. Due to the limited predictive accuracy, future studies to derive a more accurate risk score are warranted.
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| 49. |
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| 50. |
- Raza, Rizwan, et al.
(författare)
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Low-temperature solid oxide fuel cells with bioalcohol fuels
- 2017
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Ingår i: Bioenergy Systems for the Future. - : Elsevier. - 9780081010266 - 9780081010310 ; , s. 521-539
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Bokkapitel (refereegranskat)abstract
- Energy and environmental issues become key factors for sustainable development of society and national economy. Sustainable energy targeting opportunities for economic friendly growth of a country are commonly recognized. The growing interest is focused on the renewable energy resources because of the global energy demands increasing day by day. To meet the demands, an extensive research is aimed to develop sustainable energy devices such as solar cells, rechargeable batteries, and fuel cells. In recent years, solid oxide fuel cell (SOFC) among fuel-cell types has got more attention especially due to its fuel flexibility (e.g., different hydrocarbons, alcohols, and gasoline/diesel), high efficiency, and low emission. Thus, LTSOFC fed by direct bioethanol is receiving considerable attention as a clean, highly efficient for the production of both electricity and high-grade waste heat. These multifuel advantages provide the opportunities to develop an advanced SOFC system especially bioalcohol SOFC systems. This is a very dynamic area for SOFC applications with a promising future. It may create great energy savings and pollution reductions, if the bioalcohol fuel-based-technologies in these applications come into practical use.This chapter is focused on the development of LTSOFC operated by direct bioalcohol (bioethanol and biomethanol) for sustainable development. The content of this chapter is divided into three parts: (i) development of materials, (ii) characterization and analysis, (iii) demonstration of the nanocomposite materials in a bioalcohol FC, and (iv) case studies. Such bioalcohol FC research and development can enhance the use of sustainable/renewable energy for the society, and results achieved for applications have great potential to revolutionize the energy technology in an environmentally friendly and sustainable way.
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