41 research outputs found
Relationship between microscopic analysis and quantitative and qualitative indicators of moisture susceptibility evaluation of warm-mix asphalt mixtures containing modifiers
Given the defects of bitumen in asphalt mixtures particularly exposed to moisture, this study mainly aims to investigate the relationship between qualitative and quantitative results of moisture susceptibility tests on asphalt mixtures modified by ZycoTherm, nanoclay, nanosilica and SBS. The Marshall stability, modulus of resilience and indirect tensile strength tests are carried out. Boiling water and SEM qualitative tests are also used. Eventually, the qualitative tests results are digitalized through image processing by MATLAB and compared with the moisture susceptibility results of indirect tensile strength test.
For modulus of resilience testing, the results show that this modifier has the maximum impact on Marshall stability, improving it by about 23%. For moisture susceptibility testing, the nanosilica-modified mixture has the maximum effect among anti-stripping additives, with an improvement by about 20%. An investigation into the results of SEM images and boiling water test via MATLAB indicates the high accuracy of SEM images and their results show the most compatibility with the results of quantitative data
Engraftment of neural stem cells in the treatment of spinal cord injury
AbstractSpinal cord injury is one of the main causes of disability in the young population. Based on the underlying pathological changes, many modalities of treatments have been trialed. However, the most promising so far, has been the replacement of lost cellular elements, using stem cells and non-stem cells transplantation. The route of cellular administration and engraftment into the site of injury is an important determining factor for functional outcome, and should be chosen to be safe and efficacious in human patients. Herein, we will review the underlying changes following spinal cord injury, and the possible routes of cellular transplantation
The global burden of cancer attributable to risk factors, 2010-19 : a systematic analysis for the Global Burden of Disease Study 2019
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.Peer reviewe
Recommended from our members
Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021
BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation
Modeling and Fault Detection of Quadrotor with Rotor Thrust Deviation Fault
In this study, modeling and fault detection of a novel faulty quadrotor is presented. It is assumed that a quadrotor vehicle has encountered a fault during a flight accident, and as a result, one of the rotors does not operate vertically. Although the rotor's rotational axis has deviated from the vertical direction, the amount of produced thrust remains constant. Detecting this fault along with utilizing a proper controlling approach can reduce the risk of failure in the vehicle. Based on this statement, the procedure of this study has been developed in three main stages. First, the kinematic and dynamic equations governing the faulty system are driven using Newton's second law and Euler's principle. Then, equations governing the faulty system and the Thau observer are employed to calculate the residual value. This parameter is calculated based on the differences between states’ measurement and estimation. Eventually, by comparing the computed residual value with the assumed threshold, thrust deviation in the shortest possible time has been detected
How to maintain and transport equine adipose tissue for isolating mesenchymal stem cells?
Abstract Background Adipose tissue (AT) is one of the most important mesenchymal stem cell (MSC) sources because of its high quantities, availability and ease of collection. After being collected samples, they should be transported to a laboratory for stem cell (SC) isolation, culture and expansion for future clinical application. Usually, laboratories are distant from animal husbandry centers; therefore, it is necessary to provide suitable conditions for adipose tissue transportation, such that adipose-derived MSCs are minimally affected. In the current study, the impact of tissue maintenance under different conditions on MSCs derived from these tissues was evaluated. We aimed at finding suitable and practical transportation methods in which ASCs go through the slightest changes. Results In the current study, after being collected, equine AT was randomized into eight groups: four samples were maintained in stem cell culture media at 25 οC and 4 οC for 6 and 12 hrs. as transportation via SC media groups. Three samples were frozen at three different temperatures (− 20, − 75 and − 196 οC) as cryopreserved groups; these samples were defrosted 1 week after cryopreservation. Fresh and unfrozen AT was evaluated as a control group. The tissue samples were then initiated into enzymatic digestion, isolation and the culturing of SCs. Cells at passage three were used to evaluate the ability to form colonies, proliferation rate, plotting of the cell growth curve, and viability rate. All experiments were performed in triplicate. Stem cell isolation was successful in all groups, although purification of SCs from the first series of cryopreservation at − 196 οC and two series of − 20 οC was unsuccessful. There was no significant difference between the surface area of colonies in all groups except for − 20 οC. The growth rate of transportation via stem cell media at 25 οC for 6 hrs. was similar to that of the control group. MTT analysis revealed a significant difference between 25 οC 12 hrs. Group and other experimental groups except for control, 4 οC 12 hrs. and − 196 οC group. Conclusion Data have shown freezing at − 75 οC, transportation via stem cell media at 4 οC for 12 hrs. and 25 οC for 6 hrs. are acceptable tissue preservation and transportation methods due to minor effects on MSCs features
Stem cell therapy for spinal cord injury: The use of oligodendrocytes and motor neurons derived from human embryonic stem cells
Over the past few years, the understanding of stem cells as a potential therapeutic source has significantly evolved, and the previous concept of irreparable neural injury is being reconsidered. Stem cells are pluripotent cells with high differentiation potential. Induced proliferation and differentiation of these cells under optimal in vitro conditions has been used to generate different transplantable cells of various types and stages of development. For spinal cord injury recovery, the human embryonic stem cells and, recently, the human induced pluripotent stem cells are used as a main source, and two major types of cells are the target: the oligodendrocytes and motor neurons. The extensive experimental research efforts have focused on translating in vitro cellular regeneration of these cells to in vivo transplantation and survival of the transplants, in order to improve clinical outcomes. In this review, we will discuss the progressive development of the cellular generation protocols and the locomotor outcome of their transplantation at sites on spinal cord injury. Keywords: Stem cells, Spinal cord injury, Oligodendrocytes, Motor neurons, Embryonic stem cells, Induced pluripotent stem cell
Mouse models of spinal cord injury and stem cell transplantation
AbstractSpinal cord injury is one of the most devastating neurologic conditions that mostly affects young, and otherwise healthy, patients. Following the primary phase of injury, deleterious secondary inflammation and vascular disruption lead to a more sustained and permanent damage. Over the years, various animal models of spinal cord injury have been developed to help understand the mechanism and the pathophysiology of injury, and to develop reliable treatment strategies. These animal models, especially for the mouse, have also become the target of stem cell therapy, which aims to replace the lost cellular element at the site of injury. In this review, we will discuss the different types of mouse models of spinal cord injury, and elaborate on the therapeutic use of stem cells transplantation
Factors Associated With Neurological Manifestations in Patients With COVID-19
Background: The coronavirus disease 2019 (COVID-19) is the most terrible pandemic of a respiratory disease that we had in the past century. Most existing studies explore different manifestations in COVID-19. Few recent studies have described neurological manifestations of patients with COVID-19 but their associations with age, laboratory findings, and mortality rates have not been explored well. Methods: This case-control study includes 263 patients with COVID-19 without neurological symptoms (control group) and all patients with COVID-19 with the central nervous system symptoms (n=460, case group) hospitalized between February 2020 and April 2020. Data on demographic factors, medical history, symptoms, and laboratory tests, all are extracted from medical records. Results: Out of 723 patients with confirmed SARS-CoV-2 infection, 460 (63.6%) were identified to have at least one neurological manifestation. The mean ages of patients with and without neurological manifestation were 60.6±18.0 and 60.8±15.7 years, respectively. The most common symptoms were myalgia (41%), headache (20.3%), and loss of consciousness (LOC) (16.5%). Women were more likely to develop a neurological manifestation (P = 0.001). Moreover, smoking history was significantly more in patients with neurological manifestations (P=0.03). Also, we compared two groups in terms of tracheal intubation. The need for tracheal intubation was 19% and 12% in patients with and without neurological manifestations, respectively. Furthermore, the prevalence of intensive care unit (ICU) admission was 28% and 24% in patients with COVID-19, with and without neurological manifestations, respectively. Some of the neurological manifestations such as LOC, limbs weakness, and seizure might need more ICU admission and tracheal intubation. The frequency of comorbidities and the laboratory test results were almost similar between the two groups. Conclusion: Myalgia, headache, and LOC were the most common neurological manifestations and their distributions varied depending on age. Only a few neurological manifestations were related to mortality and morbidity rates, while some of them occurred in mild cases