42 research outputs found
Modeling of a Hybrid-Electric System and Design of Control Laws for Hybrid-Electric Urban Air Mobility Power Plants
Advanced Air Mobility (AAM) is an emerging market and technology in the aerospace industry. These systems are being developed to overcome traffic congestion. The current designs make use of Distributed Electric Propulsion (DEP): either fully electric or hybrid electric. The hybrid engine system consists of two power sources: prime movers, such as turbine engines, and batteries. The hybrid systems offer higher range and endurance compared with the existing fully electric systems. Hybrid-electric power generation systems for AAM have different mission requirements when compared to systems used in automobiles. Therefore, there is a particular need to model hybrid-electric systems and the development of control logic specifically for AAM aircraft. This thesis focusses on the modeling and design of control logic for hybrid-electric power plants for Advanced Air Mobility (AAM) applications. The developed model can assist in designing and optimizing the system as well as supporting the system architecture. These models can also help the testing and integration of hardware and software of systems and sub-systems, also known as software-in-the-loop and hardware-in-the-loop simulations. A state-space representation of the hybrid-electric system is created and validated with experimental results to facilitate the use of modern controls methods. A control law for the hybrid-electric system was also developed to meet the AAM aircraft mission requirement of generating the required electrical power and maintaining the State of Charge (SOC) of the batteries
Postmortem computed tomography for diagnosis of cause of death in male prisoners
Objective: To determine the utility of postmortem CT (PMCT) examination in establishing the cause of death among male prisoners dying in Karachi jails.Methods: A descriptive study was carried out from February 2006 to September 2007, CT Scan section, Civil Hospital Karachi and the Mortuary, Dow Medical College, Dow University of Health Sciences, Karachi. Adult male prisoners dying in the Karachi central prison and referred to the study setting for determining the cause of death for medico legal purpose were included. Female prisoners and those cases where the final report of cause of death was not available were excluded. CT scan of the vital body regions (head, neck, thorax, abdomen and pelvis) was carried out in all cases. The scan was read and reported by two radiologists. Anatomical dissection based autopsy was carried out by the forensic expert. Final report regarding the cause of death was issued by the forensic expert based on the combined findings, histopathology, toxicology results and circumstantial evidence. The CT scan and autopsy findings were compared and percentage agreement was determined using kappa statistics.Results: There were 14 cases in all with mean age of 41.2 +/- 17 years. The alleged mode of death was custodial torture in all cases. CT scan determined the cause of death to be natural cardio-respiratory failure in 10, strangulation in 01, pulmonary tuberculosis (TB) in 02 and trauma to spine in 01 case. The autopsy determined natural death in 11 and pulmonary TB in 02 and asphyxia in 01. The percentage agreement between CT and autopsy was 92% (k = 0.92) and between CT and finalized cause of death was 100% (k = 1.0).Conclusion: PMCT is as effective as dissection autopsy in identifying pulmonary infections and natural causes of death. It is more effective in identifying vertebral fractures which may exclude hanging and corroborate trauma to spine
Removing Digital Addiction: Through Digital Detoxication
Over-reliance on digital devices like cell phones, tablets, and iPad, has led to an individual using multiple digital devices the majority of the time when he or she is awake. Multiple device usage leads to an unconscious addictive use of a device that culminates in persistent information overload. This addictive use leads to information overload that continues even when the device is not being used or the individual is sleeping. We seek to explore if a digital detoxification app can remove digital addiction and create an impactful and healthy device usage, resulting in impactful device usage. Researchers have talked about the need for digital detoxification or digital cleansing. The popular remedies available include increased physical activities like yoga and meditation. We propose a digital detoxification model that can be used for mandatory service application of a device or the hedonistic use of an entertainment device. This model will allow individuals to use digital devices to the extent that it does not lead to addiction side effects like technostress, anxiety, insomnia, and information overload, thereby reducing digital addiction. This app will prevent an individual from unnecessarily utilizing the device while promoting optimal use, facilitating digital detoxication, and minimizing digital addiction. The digital detoxification apps will be available from all the publicly available app stores and allow the end-users to develop healthy habits and then detoxify from excessive use of the device. These apps will activate and prevent the end-user from excessively using the device. The individual will identify the safe usage time of the device. The app will activate features like airplane mode to ensure that excessive device usage is prevented and does not lead to digital toxification
Risk factors of Oral cancer- A hospital based case control study
Oral cancer is a highly prevalent malignancy in Pakistan. Among various risk factors associated with this neoplasm, habits such as smoked and smokeless tobacco usage, betel quid, and betel nut consumption are the major culprits in our society. In the present study, we aimed to ascertain prevalent risk factors for OC in our population and to compare our findings with healthy controls to establish their significance. A hospital-based case control study was conducted at Dow University of Health Sciences, Pakistan from January 2015 ? September 2016. Information pertaining to unhealthy oral habits was obtained from 62 oral cancer patients (cases) and 62 healthy controls on specifically designed proforma by the principal investigator. Smokeless tobacco is strong, independent risk factor for oral cancer development in our study population. Buccal mucosa is the predominantly affected site (71%) which corresponds with high smokeless tobacco use. All studied habits increase risk of oral cancer as demonstrated by high odds ratio. Despite advancement in our knowledge and understanding of carcinogenic potential of these hazardous substances not enough efforts have been put forth to effectively control their widespread sale and consumption, particularly by the youth in our society
Synthesis and evaluation of antioxidant and antimicrobial activities of Schiff base tin (II) complexes
Purpose: To synthesize and evaluate Schiff base Tin (II) complexes for antioxidant and antimicrobial activitiesMethods: The complexes of Tin (II) chloride with various Schiff base derivative of 2-Hydroxy-1- naphthaldehyde (HN) were synthesized and characterized by various physiochemical techniques, including elemental analysis, ultraviolet–visible (UV-Vis) spectrophotometry, Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H–NMR), carbon-13 nuclear magnetic resonance (13C-NMR), electron ionization mass spectrometry (EIMS) and conductance studies. Agarwell diffusion and agar-well dilution techniques were used for antimicrobial assessment. Evaluation of the antioxidant activity of the ligands and complexes was accomplished by DPPH radical scavenging assay.Results: The results indicate coordination of deprotonated phenolic oxygen and nitrogen of azomethine with Tin (II) chloride led to the formation of stable complexes. The Tin (II) complexes showed good antimicrobial and antioxidant activities. Compounds (HNPA and [Sn(HNPA)Cl2(H2O)2) were noteworthy (p < 0.05) in this regard with antibacterial activity against Staphylococcus aureus, while [Sn(HNCA)Cl2(H2O)2 and [Sn(HNPT)Cl2(H2O)2 were active against Klebsiella pneumoniae..Conclusion: All synthesized Schiff bases and their Tin (II) complexes showed high antimicrobial and antioxidant activities than their corresponding ligands.Keywords: Schiff base, Ligand, Tin (II) complexes, Antimicrobial, Antioxidant, Deprotonated phenolic oxyge
Hepatocellular carcinoma with extrahepatic blood supply from right renal artery
Extrahepatic blood supply is seen in around 17-27% of hepatocellular carcinoma lesions. Evidence suggests that this extrahepatic supply most commonly originates from a right intercostal artery (70-83%) followed by left intercostal, omental and right renal arteries. Thus a comprehensive knowledge of variations in standard vascular anatomy and cognisance of factors influencing or predicting extrahepatic blood supply in HCC is instrumental in ensuring the success of surgical and interventional procedures. We present the unusual case of a 66-year-old male with HCC in Segment I of the liver with aberrant blood supply from the right renal artery in the absence of any risk factors for extrahepatic circulation. He successfully underwent transarterial chemoembolization. There was no evidence of residual disease on repeat imaging
Measuring routine childhood vaccination coverage in 204 countries and territories, 1980-2019 : a systematic analysis for the Global Burden of Disease Study 2020, Release 1
Background Measuring routine childhood vaccination is crucial to inform global vaccine policies and programme implementation, and to track progress towards targets set by the Global Vaccine Action Plan (GVAP) and Immunization Agenda 2030. Robust estimates of routine vaccine coverage are needed to identify past successes and persistent vulnerabilities. Drawing from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2020, Release 1, we did a systematic analysis of global, regional, and national vaccine coverage trends using a statistical framework, by vaccine and over time. Methods For this analysis we collated 55 326 country-specific, cohort-specific, year-specific, vaccine-specific, and dosespecific observations of routine childhood vaccination coverage between 1980 and 2019. Using spatiotemporal Gaussian process regression, we produced location-specific and year-specific estimates of 11 routine childhood vaccine coverage indicators for 204 countries and territories from 1980 to 2019, adjusting for biases in countryreported data and reflecting reported stockouts and supply disruptions. We analysed global and regional trends in coverage and numbers of zero-dose children (defined as those who never received a diphtheria-tetanus-pertussis [DTP] vaccine dose), progress towards GVAP targets, and the relationship between vaccine coverage and sociodemographic development. Findings By 2019, global coverage of third-dose DTP (DTP3; 81.6% [95% uncertainty interval 80.4-82 .7]) more than doubled from levels estimated in 1980 (39.9% [37.5-42.1]), as did global coverage of the first-dose measles-containing vaccine (MCV1; from 38.5% [35.4-41.3] in 1980 to 83.6% [82.3-84.8] in 2019). Third- dose polio vaccine (Pol3) coverage also increased, from 42.6% (41.4-44.1) in 1980 to 79.8% (78.4-81.1) in 2019, and global coverage of newer vaccines increased rapidly between 2000 and 2019. The global number of zero-dose children fell by nearly 75% between 1980 and 2019, from 56.8 million (52.6-60. 9) to 14.5 million (13.4-15.9). However, over the past decade, global vaccine coverage broadly plateaued; 94 countries and territories recorded decreasing DTP3 coverage since 2010. Only 11 countries and territories were estimated to have reached the national GVAP target of at least 90% coverage for all assessed vaccines in 2019. Interpretation After achieving large gains in childhood vaccine coverage worldwide, in much of the world this progress was stalled or reversed from 2010 to 2019. These findings underscore the importance of revisiting routine immunisation strategies and programmatic approaches, recentring service delivery around equity and underserved populations. Strengthening vaccine data and monitoring systems is crucial to these pursuits, now and through to 2030, to ensure that all children have access to, and can benefit from, lifesaving vaccines. Copyright (C) 2021 The Author(s). Published by Elsevier Ltd.Peer reviewe
Accelerated surgery versus standard care in hip fracture (HIP ATTACK): an international, randomised, controlled trial
Population and fertility by age and sex for 195 countries and territories, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017
Background: Population estimates underpin demographic and epidemiological research and are used to track progress on numerous international indicators of health and development. To date, internationally available estimates of population and fertility, although useful, have not been produced with transparent and replicable methods and do not use standardised estimates of mortality. We present single-calendar year and single-year of age estimates of fertility and population by sex with standardised and replicable methods. Methods: We estimated population in 195 locations by single year of age and single calendar year from 1950 to 2017 with standardised and replicable methods. We based the estimates on the demographic balancing equation, with inputs of fertility, mortality, population, and migration data. Fertility data came from 7817 location-years of vital registration data, 429 surveys reporting complete birth histories, and 977 surveys and censuses reporting summary birth histories. We estimated age-specific fertility rates (ASFRs; the annual number of livebirths to women of a specified age group per 1000 women in that age group) by use of spatiotemporal Gaussian process regression and used the ASFRs to estimate total fertility rates (TFRs; the average number of children a woman would bear if she survived through the end of the reproductive age span [age 10–54 years] and experienced at each age a particular set of ASFRs observed in the year of interest). Because of sparse data, fertility at ages 10–14 years and 50–54 years was estimated from data on fertility in women aged 15–19 years and 45–49 years, through use of linear regression. Age-specific mortality data came from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 estimates. Data on population came from 1257 censuses and 761 population registry location-years and were adjusted for underenumeration and age misreporting with standard demographic methods. Migration was estimated with the GBD Bayesian demographic balancing model, after incorporating information about refugee migration into the model prior. Final population estimates used the cohort-component method of population projection, with inputs of fertility, mortality, and migration data. Population uncertainty was estimated by use of out-of-sample predictive validity testing. With these data, we estimated the trends in population by age and sex and in fertility by age between 1950 and 2017 in 195 countries and territories. Findings: From 1950 to 2017, TFRs decreased by 49\ub74% (95% uncertainty interval [UI] 46\ub74–52\ub70). The TFR decreased from 4\ub77 livebirths (4\ub75–4\ub79) to 2\ub74 livebirths (2\ub72–2\ub75), and the ASFR of mothers aged 10–19 years decreased from 37 livebirths (34–40) to 22 livebirths (19–24) per 1000 women. Despite reductions in the TFR, the global population has been increasing by an average of 83\ub78 million people per year since 1985. The global population increased by 197\ub72% (193\ub73–200\ub78) since 1950, from 2\ub76 billion (2\ub75–2\ub76) to 7\ub76 billion (7\ub74–7\ub79) people in 2017; much of this increase was in the proportion of the global population in south Asia and sub-Saharan Africa. The global annual rate of population growth increased between 1950 and 1964, when it peaked at 2\ub70%; this rate then remained nearly constant until 1970 and then decreased to 1\ub71% in 2017. Population growth rates in the southeast Asia, east Asia, and Oceania GBD super-region decreased from 2\ub75% in 1963 to 0\ub77% in 2017, whereas in sub-Saharan Africa, population growth rates were almost at the highest reported levels ever in 2017, when they were at 2\ub77%. The global average age increased from 26\ub76 years in 1950 to 32\ub71 years in 2017, and the proportion of the population that is of working age (age 15–64 years) increased from 59\ub79% to 65\ub73%. At the national level, the TFR decreased in all countries and territories between 1950 and 2017; in 2017, TFRs ranged from a low of 1\ub70 livebirths (95% UI 0\ub79–1\ub72) in Cyprus to a high of 7\ub71 livebirths (6\ub78–7\ub74) in Niger. The TFR under age 25 years (TFU25; number of livebirths expected by age 25 years for a hypothetical woman who survived the age group and was exposed to current ASFRs) in 2017 ranged from 0\ub708 livebirths (0\ub707–0\ub709) in South Korea to 2\ub74 livebirths (2\ub72–2\ub76) in Niger, and the TFR over age 30 years (TFO30; number of livebirths expected for a hypothetical woman ageing from 30 to 54 years who survived the age group and was exposed to current ASFRs) ranged from a low of 0\ub73 livebirths (0\ub73–0\ub74) in Puerto Rico to a high of 3\ub71 livebirths (3\ub70–3\ub72) in Niger. TFO30 was higher than TFU25 in 145 countries and territories in 2017. 33 countries had a negative population growth rate from 2010 to 2017, most of which were located in central, eastern, and western Europe, whereas population growth rates of more than 2\ub70% were seen in 33 of 46 countries in sub-Saharan Africa. In 2017, less than 65% of the national population was of working age in 12 of 34 high-income countries, and less than 50% of the national population was of working age in Mali, Chad, and Niger. Interpretation: Population trends create demographic dividends and headwinds (ie, economic benefits and detriments) that affect national economies and determine national planning needs. Although TFRs are decreasing, the global population continues to grow as mortality declines, with diverse patterns at the national level and across age groups. To our knowledge, this is the first study to provide transparent and replicable estimates of population and fertility, which can be used to inform decision making and to monitor progress. Funding: Bill & Melinda Gates Foundation