| 1. |
- Benchoula, Khaled, et al.
(författare)
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Optimization of Hyperglycemic Induction in Zebrafish and Evaluation of Its Blood Glucose Level and Metabolite Fingerprint Treated with Psychotria malayana Jack Leaf Extract
- 2019
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Ingår i: Molecules. - : MDPI. - 1431-5157 .- 1420-3049. ; 24:8
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Tidskriftsartikel (refereegranskat)abstract
- A standard protocol to develop type 1 diabetes in zebrafish is still uncertain due to unpredictable factors. In this study, an optimized protocol was developed and used to evaluate the anti-diabetic activity of Psychotria malayana leaf. The aims of this study were to develop a type 1 diabetic adult zebrafish model and to evaluate the anti-diabetic activity of the plant extract on the developed model. The ability of streptozotocin and alloxan at a different dose to elevate the blood glucose levels in zebrafish was evaluated. While the anti-diabetic activity of P. malayana aqueous extract was evaluated through analysis of blood glucose and LC-MS analysis fingerprinting. The results indicated that a single intraperitoneal injection of 300 mg/kg alloxan was the optimal dose to elevate the fasting blood glucose in zebrafish. Furthermore, the plant extract at 1, 2, and 3 g/kg significantly reduced blood glucose levels in the diabetic zebrafish. In addition, LC-MS-based fingerprinting indicated that 3 g/kg plant extract more effective than other doses. Phytosterols, sugar alcohols, sugar acid, free fatty acids, cyclitols, phenolics, and alkaloid were detected in the extract using GC-MS. In conclusion, P. malayana leaf aqueous extract showed anti-diabetic activity on the developed type 1 diabetic zebrafish model.
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| 2. |
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| 3. |
- Danaei, Goodarz, et al.
(författare)
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Effects of diabetes definition on global surveillance of diabetes prevalence and diagnosis: a pooled analysis of 96 population-based studies with 331288 participants
- 2015
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Ingår i: The Lancet Diabetes & Endocrinology. - 2213-8595 .- 2213-8587. ; 3:8, s. 624-637
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Tidskriftsartikel (refereegranskat)abstract
- Background Diabetes has been defined on the basis of different biomarkers, including fasting plasma glucose (FPG), 2-h plasma glucose in an oral glucose tolerance test (2hOGTT), and HbA(1c). We assessed the effect of different diagnostic definitions on both the population prevalence of diabetes and the classification of previously undiagnosed individuals as having diabetes versus not having diabetes in a pooled analysis of data from population-based health examination surveys in different regions. Methods We used data from 96 population-based health examination surveys that had measured at least two of the biomarkers used for defining diabetes. Diabetes was defined using HbA(1c) (HbA(1c) >= 6 . 5% or history of diabetes diagnosis or using insulin or oral hypoglycaemic drugs) compared with either FPG only or FPG-or-2hOGTT definitions (FPG >= 7 . 0 mmol/L or 2hOGTT >= 11 . 1 mmol/L or history of diabetes or using insulin or oral hypoglycaemic drugs). We calculated diabetes prevalence, taking into account complex survey design and survey sample weights. We compared the prevalences of diabetes using different definitions graphically and by regression analyses. We calculated sensitivity and specificity of diabetes diagnosis based on HbA1c compared with diagnosis based on glucose among previously undiagnosed individuals (ie, excluding those with history of diabetes or using insulin or oral hypoglycaemic drugs). We calculated sensitivity and specificity in each survey, and then pooled results using a random-effects model. We assessed the sources of heterogeneity of sensitivity by meta-regressions for study characteristics selected a priori. Findings Population prevalence of diabetes based on FPG- or-2hOGTT was correlated with prevalence based on FPG alone (r= 0 . 98), but was higher by 2-6 percentage points at different prevalence levels. Prevalence based on HbA(1c) was lower than prevalence based on FPG in 42 . 8% of age-sex-survey groups and higher in another 41 . 6%; in the other 15 . 6%, the two definitions provided similar prevalence estimates. The variation across studies in the relation between glucose-based and HbA(1c)-based prevalences was partly related to participants' age, followed by natural logarithm of per person gross domestic product, the year of survey, mean BMI, and whether the survey population was national, subnational, or from specific communities. Diabetes defined as HbA(1c) 6 . 5% or more had a pooled sensitivity of 52 . 8% (95% CI 51 . 3-54 . 3%) and a pooled specificity of 99 . 74% (99 . 71-99 . 78%) compared with FPG 7 . 0 mmol/L or more for diagnosing previously undiagnosed participants; sensitivity compared with diabetes defined based on FPG-or-2hOGTT was 30 . 5% (28 . 7-32 . 3%). None of the preselected study-level characteristics explained the heterogeneity in the sensitivity of HbA(1c) versus FPG. Interpretation Different biomarkers and definitions for diabetes can provide different estimates of population prevalence of diabetes, and differentially identify people without previous diagnosis as having diabetes. Using an HbA(1c)-based definition alone in health surveys will not identify a substantial proportion of previously undiagnosed people who would be considered as having diabetes using a glucose-based test.
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| 4. |
- Saleem, Jawad, et al.
(författare)
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An efficient method of spot welding Aluminium alloys with induction preheating
- 2016
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Ingår i: Journal of Electrical Systems. - 1112-5209. ; 12:4, s. 817-825
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Tidskriftsartikel (refereegranskat)abstract
- Steel has been the material of choice for automobile manufacturers. In the recent years material such as aluminium and its alloys are taking over the market because of their light weight. The use of aluminium, in automobile manufacturing can result in overall fuel efficiency. Spot welding aluminium alloys require higher electric power and less welding time as compared to steel. Welding guns that can produce an electric current which is approximately 2 to 3 times higher, as compared to steel are required for spot welding aluminium. An efficient method of spot welding Aluminium alloys with the preheating process has been proposed in this paper. Preheating Aluminium sheet before spot welding reduces the thermal and electrical resistance which brings down the electric current requirement to spot weld Aluminium structures. Both spot welding and induction preheating process have been modelled in this paper. The test results of the preheating process have also been verified with practical heating trials. The preheating is performed on-the-fly in advance to spot welding process. The results show that spot welding Al 6082 after preheating up to 200 degrees C, the output current requirements to make the spot weld are reduced by 22%..
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| 5. |
- Zhou, Bin, et al.
(författare)
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Worldwide trends in diabetes since 1980: A pooled analysis of 751 population-based studies with 4.4 million participants
- 2016
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Ingår i: The Lancet. - : Elsevier B.V.. - 0140-6736 .- 1474-547X. ; 387:10027, s. 1513-1530
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Tidskriftsartikel (refereegranskat)abstract
- Background: One of the global targets for non-communicable diseases is to halt, by 2025, the rise in the age standardised adult prevalence of diabetes at its 2010 levels. We aimed to estimate worldwide trends in diabetes, how likely it is for countries to achieve the global target, and how changes in prevalence, together with population growth and ageing, are aff ecting the number of adults with diabetes.Methods: We pooled data from population-based studies that had collected data on diabetes through measurement of its biomarkers. We used a Bayesian hierarchical model to estimate trends in diabetes prevalence-defined as fasting plasma glucose of 7.0 mmol/L or higher, or history of diagnosis with diabetes, or use of insulin or oral hypoglycaemic drugs-in 200 countries and territories in 21 regions, by sex and from 1980 to 2014. We also calculated the posterior probability of meeting the global diabetes target if post-2000 trends continue.Findings: We used data from 751 studies including 4372000 adults from 146 of the 200 countries we make estimates for. Global age-standardised diabetes prevalence increased from 4.3% (95% credible interval 2.4-17.0) in 1980 to 9.0% (7.2-11.1) in 2014 in men, and from 5.0% (2.9-7.9) to 7.9% (6.4-9.7) in women. The number of adults with diabetes in the world increased from 108 million in 1980 to 422 million in 2014 (28.5% due to the rise in prevalence, 39.7% due to population growth and ageing, and 31.8% due to interaction of these two factors). Age-standardised adult diabetes prevalence in 2014 was lowest in northwestern Europe, and highest in Polynesia and Micronesia, at nearly 25%, followed by Melanesia and the Middle East and north Africa. Between 1980 and 2014 there was little change in age-standardised diabetes prevalence in adult women in continental western Europe, although crude prevalence rose because of ageing of the population. By contrast, age-standardised adult prevalence rose by 15 percentage points in men and women in Polynesia and Micronesia. In 2014, American Samoa had the highest national prevalence of diabetes (>30% in both sexes), with age-standardised adult prevalence also higher than 25% in some other islands in Polynesia and Micronesia. If post-2000 trends continue, the probability of meeting the global target of halting the rise in the prevalence of diabetes by 2025 at the 2010 level worldwide is lower than 1% for men and is 1% for women. Only nine countries for men and 29 countries for women, mostly in western Europe, have a 50% or higher probability of meeting the global target.Interpretation: Since 1980, age-standardised diabetes prevalence in adults has increased, or at best remained unchanged, in every country. Together with population growth and ageing, this rise has led to a near quadrupling of the number of adults with diabetes worldwide. The burden of diabetes, both in terms of prevalence and number of adults aff ected, has increased faster in low-income and middle-income countries than in high-income countries.
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| 6. |
- Abdul-Majid, Khairul-Bariah
(författare)
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Pathogenesis of myelin oligodendrocyte glycoprotein induced experimental autoimmune encephalomyelitis in DBA/1 mice
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Experimental autoimmune encephalomyelitis (EAE) is an animal model of the human autoimmune disease, multiple sclerosis (MS). MS is prevalent among the Caucasian population and linkage analysis studies have indicated that the presence of certain MHC class II genes can increase the risk of manifesting MS. Due to the limitations of MS patient materials, EAE has provided a tool for studying the mechanisms behind the initiation, progression and remission of MS and consequently providing information on how the immune system functions in MS. In this study, myelin oligodendrocyte glycoprotein (MOG) was used with adjuvant to induce EAE in the DBA/ 1 mouse strain. We established DBA/ 1 (H2q) mice as highly susceptible to MOG-induced EAE after screening several different MHC class II congenic mice. In additon, we also established the mildest immunization protocol to date using less or even omitting adjuvant components such as Mycobacterium tuberculosis (MT) and pertussis toxin (PT). Investigation of CD4 cell deficient mice (CD4-/-) and CD8 cell deficient mice (CD8-/-), as well as of wild type DBA/ 1 mice depleted of either CD4+ T cells or CD8+ T cells, highlighted the role of CD8+ T cells in MOG-induced EAE. Co-administration of PT appeared to alter EAE susceptibility by Increasing clinical severity when MOG peptide was used. Hence use of PT for the induction of EAE in mouse strains should be re-assessed as appropriate animal models of MS as the immunological mechanisms are skewed due to the action of PT. The role of B cells was investigated using µMT and xid (lacking a B cell subpopulation) mice immunized with MOG. Both µMT and xid mice developed MOG-EAE but with decreased clinical severity as well as less demyelination in the CNS. It can therefore be concluded that B cells do not have a primary role in disease initiation, but contribute to severity of pathogenesis. We next investigated the role of Fc receptors (FcRs), since FcRs link the cellular and the humoral branches of the immune system. FcR-gamma and Fc-gammaRII deficient mice were immunized with MOG. FcR-gamma deficient mice were protected from disease while Fc-gammaRII deficient mice had enhanced disease. Thus the role of FcRs in either enhancing or downregulating cell activation is an important mechanism in disease development. This thesis presents the DBA/ 1 mouse strain as a new animal model of EAE. Using different gene-deleted mice on the DBA/ 1 background has identified the different roles of T cell subsets, B cells and FcRs in the pathogenesis of EAE. Clearly to provide an entire picture of how EAE is initiated, an overall view of the interactions within the immune system is required. Comprehending the mechanisms involved in EAE may provide further insight into the human disease, MS.
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| 7. |
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| 8. |
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| 9. |
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| 10. |
- Abdullha, Khalid A., et al.
(författare)
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Mechanical properties, thermal and chemical effect of polymer cotton bars reinforced with carbon / glass fiber
- 2024
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Ingår i: Australian Journal of Mechanical Engineering. - : Taylor & Francis. - 1448-4846 .- 2204-2253. ; 22:3, s. 592-602
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Tidskriftsartikel (refereegranskat)abstract
- Many researchers are interested in using natural fibres to treat due to recent advancements in polymer characteristics. The mechanical properties of three types of bars are studied in this paper: Cotton Fibre-Reinforced Polymer bars, Cotton/Carbon Fibre-Reinforced Polymer bars, and Cotton/Glass Fibre-Reinforced Polymer bars. The goal of the paper was to create low-cost bars with comparable mechanical performance and corrosion resistance to steel reinforcement. The bars were made using two methods: fibres immersed in polymer and fibres coated with polymer by repeated tension and relaxation of fibres. The second method produced better results in terms of the tensile strength of Cot.CFRP, Cot.GFRP, and Cot.FRP bars, which were 688, 477, and 284 MPa, respectively, and the stress–strain curve revealed brittle behaviour for all bars and modulus of elasticity of 43, 31 and 22 GPa. When sand was put on the bar’s surface, the bars demonstrated a good connection with the concrete. It also showed good resistance to moisture, alkaline solutions and acids, as well as heat resistance at temperatures below 200°C.
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| 11. |
- Azeem, Muhammad, et al.
(författare)
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Combined Economic Emission Dispatch in Presence of Renewable Energy Resources Using CISSA in a Smart Grid Environment
- 2023
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Ingår i: Electronics. - : MDPI. - 2079-9292. ; 12:3
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Tidskriftsartikel (refereegranskat)abstract
- The geographically spatial and controlled distribution of fossil fuel resources, catastrophic global warming, and depletion of fossil fuel resources have forced us to integrate zero- or low-emissions energy resources, such as wind and solar, in the generation mix. These renewable energy resources are unexhausted, available around the globe, and free of cost. The advancement in wind and solar technologies has caused an appreciable decrease in installed the and global levelized costs of electricity via these sources. Therefore, the penetration of renewable energy resources in the generation mix can provide a promising solution to the above-mentioned problems. The aim of simultaneously reducing fuel consumption in terms of “Fuel Cost” and “Emission” in thermal power plants is called a combined economic emission dispatch problem. It is a combinatorial and multi-objective optimization problem. The solution of this problem is to allocate the load demand and losses on the committed units in such way that the overall costs of the generation and emission of thermal units are reduced, while the legal bounds (constraints) are met. It is a highly non-linear and complex optimization problem. The valve-point loading effect makes this problem non-convex. The addition of renewable energy resources (RERs) adds more complexities to this problem because they are intermittent. In this work, chaotic salp swarm algorithms (CISSA) are used to solve the combined economic emission dispatch problem. Chaos is used as an alternative to randomization for the tuning of the control variable to improve the trait of obtaining global extrema. Different test cases having different combinations of thermal, solar, and wind units are solved using the proposed algorithm. The results show the superiority of this study in comparison to the existent research results in terms of the cost of generation and emissions.
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| 12. |
- Bakar, Muhammad Abu, 1969-, et al.
(författare)
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Dual-mode stable performance Phase-Shifted Full-Bridge converter for wide-input and medium power applications
- 2021
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Ingår i: IEEE transactions on power electronics. - 0885-8993 .- 1941-0107. ; 36:6, s. 6375-6388
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Tidskriftsartikel (refereegranskat)abstract
- Power converters with an extended range of line voltage are the main requirement in today's industrial applications like photovoltaic and supercapacitors based energy systems. The variation in the line voltage severely degrades the performance of power converters, because of the extended freewheeling interval, more circulation current, narrow range of zero voltage switching and increased EMI. This work suggests a modified Phase-Shifted Full-Bridge converter that cuts the freewheeling interval and minimizes these problems. It extends the input voltage range by keeping the operational duty cycle of the converter high over the wide range of input voltage while maintaining the performance stable. The proposed converter consists of four low profile transformers having reconfigurable interconnection structure. There are two distinct reconfigurable modes, a series mode and a parallel mode, which can be configured with changes in the operational conditions. The operation of the proposed converter with high switching frequency improves power density. Additionally, the use of multiple transformers minimizes heat management efforts and reduces the overall volume of the converter. The proposed work is validated in hardware characterization for a wide range of input voltage 100-400Vdc and up to the load power of 1kW. The measured energy efficiency of the proposed converter remains stable over the complete range input voltage 100-400Vdc.
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| 13. |
- Bentham, James, et al.
(författare)
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A century of trends in adult human height
- 2016
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Ingår i: eLIFE. - 2050-084X. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.522.7) and 16.5 cm (13.319.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries.
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| 14. |
- Bentham, James, et al.
(författare)
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A century of trends in adult human height
- 2016
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Ingår i: eLIFE. - : eLife Sciences Publications Ltd. - 2050-084X. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5–22.7) and 16.5 cm (13.3– 19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8– 144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries.
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| 15. |
- de Erausquin, Gabriel A, et al.
(författare)
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Chronic neuropsychiatric sequelae of SARS-CoV-2: Protocol and methods from the Alzheimer's Association Global Consortium.
- 2022
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Ingår i: Alzheimer's & dementia (New York, N. Y.). - : Wiley. - 2352-8737. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Coronavirus disease 2019 (COVID-19) has caused >3.5 million deaths worldwide and affected >160 million people. At least twice as many have been infected but remained asymptomatic or minimally symptomatic. COVID-19 includes central nervous system manifestations mediated by inflammation and cerebrovascular, anoxic, and/or viral neurotoxicity mechanisms. More than one third of patients with COVID-19 develop neurologic problems during the acute phase of the illness, including loss of sense of smell or taste, seizures, and stroke. Damage or functional changes to the brain may result in chronic sequelae. The risk of incident cognitive and neuropsychiatric complications appears independent from the severity of the original pulmonary illness. It behooves the scientific and medical community to attempt to understand the molecular and/or systemic factors linking COVID-19 to neurologic illness, both short and long term.This article describes what is known so far in terms of links among COVID-19, the brain, neurological symptoms, and Alzheimer's disease (AD) and related dementias. We focus on risk factors and possible molecular, inflammatory, and viral mechanisms underlying neurological injury. We also provide a comprehensive description of the Alzheimer's Association Consortium on Chronic Neuropsychiatric Sequelae of SARS-CoV-2 infection (CNS SC2) harmonized methodology to address these questions using a worldwide network of researchers and institutions.Successful harmonization of designs and methods was achieved through a consensus process initially fragmented by specific interest groups (epidemiology, clinical assessments, cognitive evaluation, biomarkers, and neuroimaging). Conclusions from subcommittees were presented to the whole group and discussed extensively. Presently data collection is ongoing at 19 sites in 12 countries representing Asia, Africa, the Americas, and Europe.The Alzheimer's Association Global Consortium harmonized methodology is proposed as a model to study long-term neurocognitive sequelae of SARS-CoV-2 infection.The following review describes what is known so far in terms of molecular and epidemiological links among COVID-19, the brain, neurological symptoms, and AD and related dementias (ADRD)The primary objective of this large-scale collaboration is to clarify the pathogenesis of ADRD and to advance our understanding of the impact of a neurotropic virus on the long-term risk of cognitive decline and other CNS sequelae. No available evidence supports the notion that cognitive impairment after SARS-CoV-2 infection is a form of dementia (ADRD or otherwise). The longitudinal methodologies espoused by the consortium are intended to provide data to answer this question as clearly as possible controlling for possible confounders. Our specific hypothesis is that SARS-CoV-2 triggers ADRD-like pathology following the extended olfactory cortical network (EOCN) in older individuals with specific genetic susceptibility.The proposed harmonization strategies and flexible study designs offer the possibility to include large samples of under-represented racial and ethnic groups, creating a rich set of harmonized cohorts for future studies of the pathophysiology, determinants, long-term consequences, and trends in cognitive aging, ADRD, and vascular disease.We provide a framework for current and future studies to be carried out within the Consortium. and offers a "green paper" to the research community with a very broad, global base of support, on tools suitable for low- and middle-income countries aimed to compare and combine future longitudinal data on the topic.The Consortium proposes a combination of design and statistical methods as a means of approaching causal inference of the COVID-19 neuropsychiatric sequelae. We expect that deep phenotyping of neuropsychiatric sequelae may provide a series of candidate syndromes with phenomenological and biological characterization that can be further explored. By generating high-quality harmonized data across sites we aim to capture both descriptive and, where possible, causal associations.
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| 16. |
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| 17. |
- Drake, TM, et al.
(författare)
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Surgical site infection after gastrointestinal surgery in children: an international, multicentre, prospective cohort study
- 2020
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Ingår i: BMJ global health. - : BMJ. - 2059-7908. ; 5:12
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Tidskriftsartikel (refereegranskat)abstract
- Surgical site infection (SSI) is one of the most common healthcare-associated infections (HAIs). However, there is a lack of data available about SSI in children worldwide, especially from low-income and middle-income countries. This study aimed to estimate the incidence of SSI in children and associations between SSI and morbidity across human development settings.MethodsA multicentre, international, prospective, validated cohort study of children aged under 16 years undergoing clean-contaminated, contaminated or dirty gastrointestinal surgery. Any hospital in the world providing paediatric surgery was eligible to contribute data between January and July 2016. The primary outcome was the incidence of SSI by 30 days. Relationships between explanatory variables and SSI were examined using multilevel logistic regression. Countries were stratified into high development, middle development and low development groups using the United Nations Human Development Index (HDI).ResultsOf 1159 children across 181 hospitals in 51 countries, 523 (45·1%) children were from high HDI, 397 (34·2%) from middle HDI and 239 (20·6%) from low HDI countries. The 30-day SSI rate was 6.3% (33/523) in high HDI, 12·8% (51/397) in middle HDI and 24·7% (59/239) in low HDI countries. SSI was associated with higher incidence of 30-day mortality, intervention, organ-space infection and other HAIs, with the highest rates seen in low HDI countries. Median length of stay in patients who had an SSI was longer (7.0 days), compared with 3.0 days in patients who did not have an SSI. Use of laparoscopy was associated with significantly lower SSI rates, even after accounting for HDI.ConclusionThe odds of SSI in children is nearly four times greater in low HDI compared with high HDI countries. Policies to reduce SSI should be prioritised as part of the wider global agenda.
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| 18. |
- Hajrezaie, Maryam, et al.
(författare)
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Biochanin A Gastroprotective Effects in Ethanol-Induced Gastric Mucosal Ulceration in Rats
- 2015
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:3
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Tidskriftsartikel (refereegranskat)abstract
- Background Biochanin A notable bioactive compound which is found in so many traditional medicinal plant. In vivo study was conducted to assess the protective effect of biochanin A on the gastric wall of Spraguedawley rats' stomachs. Methodology The experimental set included different animal groups. Specifically, four groups with gastric mucosal lesions were receiving either a) Ulcer control group treated with absolute ethanol (5 ml/kg), b) 20 mg/kg of omeprazole as reference group, c) 25 of biochanin A, d) 50 mg/kg of biochanin A. Histopathological sectioning followed by immunohistochemistry staining were undertaken to evaluate the influence of the different treatments on gastric wall mucosal layer. The gastric secretions were collected in the form of homogenate and exposed to superoxide dismutase (SOD) and nitric oxide enzyme (NO) and the level of malondialdehyde (MDA) and protein content were measured. Ulceration and patchy haemorrhage were clearly observed by light microscopy. The morphology of the gastric wall as confirmed by immunohistochemistry and fluorescent microscopic observations, exhibited sever deformity with notable thickness, oedematous and complete loss of the mucosal coverage however the biochanin-pretreated animals, similar to the omeprazole-pretreated animals, showed less damage compared to the ulcer control group. Moreover, up-regulation of Hsp70 protein and down-regulation of Bax protein were detected in the biochanin A pre-treated groups and the gastric glandular mucosa was positively stained with Periodic Acid Schiff (PAS) staining and the Leucocytes infiltration was commonly seen. Biochanin A displayed a great increase in SOD and NO levels and decreased the release of MDA. Conclusions This gastroprotective effect of biochanin A could be attributed to the enhancement of cellular metabolic cycles perceived as an increase in the SOD, NO activity, and decrease in the level of MDA, and also decrease in level of Bax expression and increase the Hsp70 expression level.
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| 19. |
- Hamza, Nidal, et al.
(författare)
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SIM-PFED: A Simulation-Based Decision Making Model of Patient Flow for Improving Patient Throughput Time in Emergency Department
- 2021
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Ingår i: IEEE Access. - 2169-3536 .- 2169-3536. ; 9, s. 103419-103439
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Tidskriftsartikel (refereegranskat)abstract
- Healthcare sectors face multiple threats, and the hospital emergency department (ED) is one of the most crucial hospital areas. ED plays a key role in promoting hospitals' goals of enhancing service efficiency. ED is a complex system due to the stochastic behavior of patient arrivals, the unpredictability of the care required by patients, and the department's complex nature. Simulations are effective tools for analyzing and optimizing complex ED operations. Although existing ED simulation models have substantially improved ED performance in terms of ensuring patient satisfaction and effective treatment services, many deficiencies continue to exist in addressing the key challenge in ED, namely, long patient throughput time. The patient throughput time issue is affected by causative factors, such as waiting time, length of stay, and decision-making. This research aims to develop a new simulation model of patient flow for ED (SIM-PFED) to address the reported key challenge of the patient throughput time. SIM-PFED introduces a new process for patient flow in ED on the basis of the newly proposed operational patient flow by combining discrete event simulation and agent-based simulation and applying a multi-attribute decision-making method, namely, the technique for order preference by similarity to the ideal solution. Experiments were performed on three actual hospital ED datasets to assess the effectiveness of SIM-PFED. Experimental results revealed the superiority of SIM-PFED over other alternative models in reducing patient throughput time in ED by consuming less patient waiting time and having a shorter length of stay. The findings also demonstrated the effectiveness of SIM-PFED in helping ED decision-makers select the best scenarios to be implemented in ED for ensuring minimal throughput time while being cost effective.
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| 20. |
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| 21. |
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| 22. |
- Majid, Abdul, 1973-, et al.
(författare)
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Analysis of feedback in converter using coreless printed circuit board transformer
- 2013
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Ingår i: Electrical Machines and Power Electronics and 2011 Electromotion Joint Conference (ACEMP), 2011 International Aegean Conference on. - : IEEE conference proceedings. - 9781467350020 ; , s. 601-604
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Konferensbidrag (refereegranskat)abstract
- Power supply is an inevitable component for all electronic instruments as a constant DC source. Almost all power supplies use feedback loop to achieve constant DC output voltage. In a feedback loop, the galvanic isolation is required between input and output. It can be achieved either by implementation of opto-coupler feedback on the secondary side or magnetic feedback. In this paper both opto-coupler and auxiliary feed-back techniques are implemented and analyzed in a high frequency half bridge converter using coreless Printed Circuit Board (PCB) power transformer. The implementation of opto-coupler feedback is temperature sensitive and has relatively high cost. The auxiliary winding of transformer can also be used to provide feedback signals as alternate to opto-coupler. Auxiliary feedback implementation is cheaper, temperature stable and insensitive to temperature variations. In this paper, the feasibility of feedback using auxiliary winding of coreless PCB power transformer is investigated. It is observed that this technique can be used as an alternative to opto-coupler feedback.
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| 23. |
- Majid, Abdul, et al.
(författare)
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Analysis of radiated EMI for power converters switching in MHz frequency range
- 2013
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Ingår i: Proceedings - 2013 9th IEEE International Symposium on Diagnostics for Electric Machines, Power Electronics and Drives, SDEMPED 2013. - : IEEE conference proceedings. - 9781479900251 ; , s. 428-432
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Konferensbidrag (refereegranskat)abstract
- The higher switching frequency in combination with di/dt loops and dv/dt nodes in the power stages of high frequency power converters generates higher order harmonics which cause Electro Magnetic Interference (EMI). It is commonly perceived that high frequency converters are more vulnerable to radiated EMI, thus, it is very important to analyze the radiated emission of these converters. According to the author’s knowledge, the analysis of the radiated emission of power converters switching in the MHz frequency region has not been presented until now. Therefore, in this paper, the measurements, and analysis of the near field radiated emissions of these emerging power converters is presented. These measurements are beneficial in the early design stage of power converters. Both E-field and H-field and captured and analyzed for a half bridge converter switching at 3 MHz and at the output power level of 25 W. The effects of the magnetic and electric field emissions with the addition of a Y-capacitor and secondary side common mode choke are analyzed.
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| 24. |
- Majid, Abdul, 1973-, et al.
(författare)
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Design and implementation of EMI filter for high frequency (MHz) power converters
- 2012
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Ingår i: IEEE International Symposium on Electromagnetic Compatibility. - : IEEE conference proceedings. ; , s. Art. no. 6396738-
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Konferensbidrag (refereegranskat)abstract
- The fabrication of emerging power semiconductor devices and high frequency PCB power transformers has made it possible to design the power converters in MHz switching frequency range. However, the higher switching frequency, di/dt loops and dv/dt nodes in power stages of these converters generate higher order harmonics which causes Electro Magnetic Interference (EMI). It is commonly believed that the EMI has worst affect in the converters switching in MHz frequency range than the converters operating below 150 kHz. Thus, it is important research direction to investigate the consequences of implementing a line filter to suppress the conducted EMI in high frequency power converters. In this paper, the measurements, and analysis of the conducted EMI in emerging power converters, switching in MHz frequency range, and the design of the filter for its suppression is presented. The design of LISN and its PCB implementation for EMI measurements is presented. The measurement of conducted EMI of a half bridge DC-DC converter switching at 3.45 MHz and the analysis of the frequency spectrum is discussed. The design, PCB implementation and characterization of the EMI filter and the measurement of the suppressed conducted noise by applying the filter are also discussed.
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| 25. |
- Majid, Abdul, 1973-, et al.
(författare)
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EMI filter design for high frequency power converters
- 2012
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Ingår i: 2012 11th International Conference on Environment and Electrical Engineering, EEEIC 2012. - : IEEE conference proceedings. - 9781457718304 ; , s. 586-589
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Konferensbidrag (refereegranskat)abstract
- With the emerging power semiconductor devices in GaN and SiC technology and the development of high frequency multilayered PCB power transformers, power efficient DC-DC converters are designed in megahertz switching frequency range. The increased switching frequency in combination with sudden changes in current “di/dt” or voltage “dv/dt” levels generate higher order harmonics, which cause Electro Magnetic Interference (EMI). One of the major challenges, to design the power stage of these converters, is to minimize the EMI because it affects their Electro Magnetic Compatibility (EMC). There is a spread belief that the EMI becomes much worse in a MHz switching converter compared to the current ones operating below 150 kHz. This paper investigates the consequences on implementation of a line filter for suppressing conducted EMI in high frequency power converters. The results are based on electronic simulations, comparing EMI and filter design, for a 200 kHz and 2 MHz buck converter under similar conditions. By analyzing the noise frequency spectrum of both the converters it is observed that the size of filter components, such as capacitors and common mode chokes is greatly reduced in case of 2MHz Buck converter. The results show that the size reduction that can be accomplished by increasing the switching frequency to MHz range can be improved further by a smaller implementation of the line filter as well.
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| 26. |
- Majid, Abdul, et al.
(författare)
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EMI Suppression in High Frequency Half Bridge Converter
- 2013
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Ingår i: Elektronika ir Elektrotechnika. - Kauno Technologijos Universitetas Lithuania : Kaunas University of Technology (KTU). - 1392-1215. ; 19:9, s. 75-80
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Tidskriftsartikel (refereegranskat)abstract
- Electromagnetic effects influence the design of power converters switching in MHz frequency region. In these converters, the high switching frequency in combination with sudden changes in current and voltage levels generate higher order harmonics which causes Electro Magnetic Interference (EMI). To study the effects of increased switching frequency on conducted EMI, the harmonics amplitudes are analyzed by increasing the switching frequency of a two wire input half bridge power converter from 1.32 MHz to 3 MHz. In order to suppress the Common Mode (CM) conducted EMI, different possibilities of connecting the Y- capacitor in a two wire universal input half bridge converter are discussed and the conducted EMI is measured and analyzed by connecting the Y- capacitor at different points. The line filters are designed, characterized and implemented in order to suppress conducted EMI. The effects of increased switching frequency on the line filter design are studied by analysing the EMI spectrum of both the converters. The analysis of results indicates that the filter size is reduced by increasing the switching frequency of the power converter.
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| 27. |
- Majid, Abdul, 1973-, et al.
(författare)
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High Frequency Half-Bridge Converter using Multilayered Coreless PrintedCircuit Board Step-Down Power Transformer
- 2011
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Ingår i: 8th International Conference on Power Electronics - ECCE Asia: "Green World with Power Electronics", ICPE 2011-ECCE Asia. - : IEEE conference proceedings. - 9781612849560 - 9781612849584 ; , s. 1177-1181
-
Konferensbidrag (refereegranskat)abstract
- This paper introduces high frequencyhalf bridgeDC-DC converter, using multilayered coreless Printed Circuit Board (PCB) step down power transformer. The converter is simulated and then implemented on a PCB. Complementary Pulse Width Modulated (PWM) signals are generated to turn on high and low side Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) alternately by a micro-controller. The isolated gate drive signals are provided to the high side MOSFET by using high frequency coreless PCB isolation transformer. We tested the converter for switching frequency range of 2 to 3 MHz, and for maximum input voltage up-to 170 V. The maximum output power achieved is 40 W and the maximum energy efficiency is approximately 82 %. © 2011 IEEE.
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| 28. |
- Majid, Abbasi, et al.
(författare)
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miR-124-3p Suppresses the Invasiveness and Metastasis of Hepatocarcinoma Cells via Targeting CRKL
- 2020
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Ingår i: Frontiers in Molecular Biosciences. - : Frontiers Media SA. - 2296-889X .- 2296-889X. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Abnormal expressions of microRNAs are involved in growth and progression of human cancers including hepatocellular carcinoma (HCC). An adaptor protein CRKL plays a pivotal role in HCC growth, whereas miR-124-3p downregulation is associated with clinical stage and the poor survival of patients. However, the relationship between miR-124-3p and CRKL and the molecular mechanisms through which they regulate HCC metastasis remains unclear. In the current work, we explored miR-124-3p and its correlation with CRKL expression in HCC patient tissues. We found that miR-124-3p deficiency is inversely co-related with CRKL overexpression in tumorous tissues of HCC patients, which was also consistent in HCCLM3 and Huh7 HCC cell lines. Target validation data shows that miR-124-3p directly targets CRKL. The overexpression of miR-124-3p reverses the CRKL expression at both mRNA and protein levels and inhibits the cell development, migration, and invasion. Mechanistic investigations showed that CRKL downregulation suppresses the ERK pathway and EMT process, and concomitant decrease in invasion and metastasis of HCC cells. The expressions of key molecules in the ERK pathway such as RAF, MEK, ERK1/2, and pERK1/2 and key promoters of EMT such as N-cadherin and vimentin were downregulated, whereas E-cadherin, a key suppression indicator of EMT, was upregulated. MiR-124-3p-mediated CRKL suppression led to BAX/BCL-2 increase and C-JUN downregulation, which inhibited the cell proliferation and promoted the apoptosis in HCC cells. Collectively, our data illustrates that miR-124-3p acts as an important tumor-suppressive miRNA to suppress HCC carcinogenesis through targeting CRKL. The miR-124-3p-CRKL axial regulated pathway may offer valuable indications for cancer research, diagnosis, and treatment.
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| 29. |
- Owaid, Haider M., et al.
(författare)
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Utilization of nanoparticles and waste materials in cement mortars
- 2023
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Ingår i: Journal of the Mechanical Behavior of Materials. - : Walter de Gruyter. - 0334-8938 .- 2191-0243. ; 32:1
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Tidskriftsartikel (refereegranskat)abstract
- Cement has shaped the modern built environment, but its production generates substantial carbon dioxide emissions. Consequently, there is an urgent need to identify alternative cementitious building materials for sustainable construction. In this study, cement mortars (CMs) were produced by partially replacing cement with nanoclay (NC) and granite dust (GD). The replacement proportions (% by weight of cement) of these materials were 1.5, 3, and 4.5% for NC and 10, 20, and 30% for GD. For mortars containing NC but not GD, the strength was maximized when the NC replacement proportion was 3%. To evaluate the combined effect of partially replacing cement with both NC and GD on the fresh and hardening properties of cement-blended mortars, ternary binder mixtures containing 3% NC together with 10, 20, or 30% GD were prepared, and their workability, bulk density, compressive strength (at 7, 28, and 90 days), and flexural strength were measured. Increasing the content of NC and/or GD reduced the flowability of these mortars relative to that of the reference mortar mix because it increased the content of fine materials. CM containing 3% NC and 10% GD had the highest compressive strength at 7, 28, and 90 days while also having the greatest flexural strength when compared to the control mix. This is most likely due to the high silica and alumina content of NC and GD, as well as their high specific surface area, which would improve the maturity and density of the matrix when compared to cement alone.
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| 30. |
- Saleem, Jawad, et al.
(författare)
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3 Dimensional Finite Element Simulation of Seam Welding Process
- 2013
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Ingår i: Elektronika Ir Elektrotechnika. - : Kaunas University of Technology (KTU). - 1392-1215. ; 19:8, s. 73-78
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Tidskriftsartikel (refereegranskat)abstract
- The versatility, rich mathematical formulations and robustness of finite element methods make them attractive for simulations for a wide range of problems. Two dimensional models concerning the seam welding process do have some limitations. The longitudinal two dimensional models cannot be used to examine the effects of the electrode shape and thickness regarding heat generation during the seam welding process. The transversal two dimensional models are not helpful for examining the nugget growth during the seam welding process. The heat energy generated during the seam welding process mainly depends on the resistance between the electrodes, welding current, rotational speed and the geometry of the electrodes. The settings for appropriate parameters in relation to a seam welding machine, with regards to sheets of different thicknesses, depends on trial and error methods. These methods are expensive and time consuming. The three dimensional model developed in this paper is a step towards selecting the appropriate welding parameters so as to produce a good welding nugget.
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| 31. |
- Saleem, Jawad, et al.
(författare)
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A study of IGBT rupture phenomenon in medium frequency resistance welding machine
- 2013
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Ingår i: Electrical Machines and Power Electronics and 2011 Electromotion Joint Conference (ACEMP), 2011 International Aegean Conference on. - : IEEE conference proceedings. - 9781467350020 ; , s. 236-239
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Konferensbidrag (refereegranskat)abstract
- Inverter drive resistance spot welding machines are becoming a good choice of welding because of the increased machine efficiency and output power. The DC link capacitors in spot welding equipment store a large amount of energy. In case of any failure, the IGBT in the inverter has a risk of exhibiting a violent rupture. This rupture can damage the converter, drive down time and personal injury which may lead to the machinery certification problems. IGBT failure detection and solution for protection of these failures in resistance welding machines have not been reported in literature. Literature study of the IGBT failure, rupture, fault detection and protection has been carried out for inverter drives in power applications. On the basis of the findings some protection schemes and important measures in the design of the machine have been adopted which have resulted in the reduced risk of IGBT failure.
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| 32. |
- Saleem, Jawad, 1975-, et al.
(författare)
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High Frequency Full Bridge Converter using Multilayer Coreless Printed Circuit Board Step-up Power Transformer
- 2011
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Ingår i: 2011 20th European Conference on Circuit Theory and Design, ECCTD 2011. - : IEEE conference proceedings. - 9781457706189 ; , s. 805-808
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Konferensbidrag (refereegranskat)abstract
- In designing switch mode power supply (SMPS), thedesirable feature is to have an efficient and compact design. Themain idea is to increase the switching frequency and reduce thebulky magnetic parts of the converter. This leads to a compactsize, less weight, reduced cost and increased power density of theconverter. This paper presents a high frequency full bridge DC toDC converter, using a multilayer coreless printed circuit board(PCB) step-up power transformer. The converter was simulatedand also implemented on the PCB. The pulse width modulated(PWM) signals were generated, using a microcontroller, to switchthe Metal oxide semiconductor field effect transistor (MOSFET).The design of the converter is tested up to the power levels of 5Watts with the switching frequency in 2 to 3MHz range. Theenergy efficiency of the converter is 74.86% at 2.4 MHz.
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| 33. |
- Saleem, Jawad, 1975-, et al.
(författare)
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Nugget Formation During Resistance Spot Welding Using Finite Element Model
- 2012
-
Ingår i: World Academy of Science, Engineering and Technology: An International Journal of Science, Engineering and Technology. - 2010-376X .- 2070-3740. ; 67
-
Tidskriftsartikel (refereegranskat)abstract
- Resistance spot welding process comprises of electric, thermal and mechanical phenomenon, which makes this process complex and highly non-linear and thus, it becomes difficult to model it. In order to obtain good weld nugget during spot welding, hit and trial welds are usually done which is very costly. Therefore the numerical simulation research has been conducted to understand the whole process. In this paper three different cases were analyzed by varying the tip contact area and it was observed that, with the variation of tip contact area the nugget formation at the faying surface is affected. The tip contact area of the welding electrode becomes large with long welding cycles. Therefore in order to maintain consistency of nugget formation during the welding process, the current compensation in control feedback is required. If the contact area of the welding electrode tip is reduced, a large amount of current flows through the faying surface, as a result of which sputtering occurs.
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| 34. |
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| 35. |
- Saleem, Jawad, 1975-, et al.
(författare)
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Study the influence of the alignment and nearby metallic objects on the Hall sensor system for current measurement in Resistance Spot Welding Machine
- 2011
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Ingår i: 2011 10th International Conference on Environment and Electrical Engineering, EEEIC.EU 2011 - Conference Proceedings. - : IEEE conference proceedings. ; , s. Art. no. 5874717-
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Konferensbidrag (refereegranskat)abstract
- A technique for measuring the current of a stationaryspot welding unit using a Hall sensor system is implemented. HallEffect sensor is used to sense the strength of the magnetic fieldproduced by the current, flowing through the welding electrodes,on the secondary side of welding transformer. In contrast to acurrent transformer the Hall Effect sensor can read a DC currentand can thus be utilized in direct current welding equipments. Inthis paper the influence of the sensor position and presence of thetools or other materials in the proximity of the sensor that effectthe sensor reading is investigated. COMSOL Multiphysicssoftware is used to investigate these effects and a circuit design isimplemented according to the conclusion drawn from the simulations.
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| 36. |
- Shanmugam, Vigneshwaran, et al.
(författare)
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Experimental Investigation of Thrust Force, Delamination and Surface Roughness in Drilling Hybrid Structural Composites
- 2021
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Ingår i: Materials. - : MDPI. - 1996-1944. ; 14:16
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Tidskriftsartikel (refereegranskat)abstract
- Filled hybrid composites are widely used in various structural applications where machining is critical. Hence, it is essential to understand the performance of the fibre composites’ machining behaviour. As such, a new hybrid structural composite was fabricated with redmud as filler and sisal fibre as reinforcement in polyester matrix. The composite was then tested for its drilling performance. A comprehensive drilling experiment was conducted using Taguchi L27 orthogonal array. The effect of the drill tool point angle, the cutting speed, the feed rate on thrust force, delamination, and burr formation were analysed for producing quality holes. The significance of each parameter was analysed, and the experimental outcomes revealed some important findings in the context of the drilling behaviour of sisal fibre/polyester composites with redmud as a filler. Spindle speed contributed 39% in affecting the thrust force, while the feed rate had the maximum influence of ca. 38% in affecting delamination.
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| 37. |
- Svensson, Lars, et al.
(författare)
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A comparative analysis of B cell-mediated myelin oligodendrocyte glycoprotein-experimental autoimmune encephalomyelitis pathogenesis in B cell-deficient mice reveals an effect on demyelination.
- 2002
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Ingår i: European Journal of Immunology. - 1521-4141 .- 0014-2980. ; 32:7, s. 1939-1946
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Tidskriftsartikel (refereegranskat)abstract
- We have investigated the role of B cells in myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE) using B cell-deficient mice muMT) and mice bearing the X-linked immunodeficiency (xid). The mice were immunized with MOG(1-125 )in complete Freund's adjuvant but without use of pertussis toxin. B cell-deficient muMT mice on different genetic backgrounds (C57BL/10 and DBA/1 strains) developed EAE, although with a reduced clinical severity. Histological analyses revealed decreased demyelination in the central nervous system while the influx of inflammatory cells was similar or only slightly reduced as compared to B cell-sufficient control mice. Xid mice on the DBA/1 background also developed disease with a reduced disease severity. The anti-MOG antibody response in the xid mice was decreased, while the T cell response to MOG was unaffected. We thus demonstrate that B cells are not critical for the development of MOG-induced EAE but contribute to the severity. The contribution of B cells to pathogenesis appears to be mainly through demyelination rather than through inflammation.
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| 38. |
- Zahedifard, Maryam, et al.
(författare)
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Synthesis of Apoptotic New Quinazolinone-Based Compound and Identification of its Underlying Mitochondrial Signalling Pathway in Breast Cancer Cells
- 2015
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Ingår i: Current pharmaceutical design. - 1381-6128 .- 1873-4286. ; 21:23, s. 3417-3426
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Tidskriftsartikel (refereegranskat)abstract
- The anti-carcinogenic effect of the new quinazolinone compound, named MMD, was tested on MCF-7 human breast cancer cell line. The synthesis of quinazolinone-based compounds attracted strong attention over the past few decades as an alternative mean to produce analogues of natural products. Quinazolinone compounds sharing the main principal core structures are currently introduced in the clinical trials and pharmaceutical markets as anti-cancer agents. Thus, it is of high clinical interest to identify a new drug that could be used to control the growth and expansion of cancer cells. Quinazolinone is a metabolite derivative resulting from the conjugation of 2-aminobenzoyhydrazide and 5-methoxy-2-hydroxybenzaldehyde based on condensation reactions. In the present study, we analysed the influence of MMD on breast cancer adenoma cell morphology, cell cycle arrest, DNA fragmentation, cytochrome c release and caspases activity. MCF-7 is a type of cell line representing the breast cancer adenoma cells that can be expanded and differentiated in culture. Using different in vitro strategies and specific antibodies, we demonstrate a novel role for MMD in the inhibition of cell proliferation and initiation of the programmed cell death. MMD was found to increase cytochrome c release from the mitochondria to the cytosol and this effect was enhanced over time with effective IC50 value of 5.85 +/- 0.71 mu g/mL detected in a 72-hours treatment. Additionally, MMD induced cell cycle arrest at G0/G1 phase and caused DNA fragmentation with obvious activation of caspase-9 and caspases-3/7. Our results demonstrate a novel role of MMD as an anti-proliferative agent and imply the involvement of mitochondrial intrinsic pathway in the observed apoptosis.
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