116 research outputs found
Analytical testing
Analytical methods for combining flight acceleration and strain data with shake test mobility data to predict the effects of structural changes on flight vibrations and strains are presented. This integration of structural dynamic analysis with flight performance is referred to as analytical testing. The objective of this methodology is to analytically estimate the results of flight testing contemplated structural changes with minimum flying and change trials. The category of changes to the aircraft includes mass, stiffness, absorbers, isolators, and active suppressors. Examples of applying the analytical testing methodology using flight test and shake test data measured on an AH-1G helicopter are included. The techniques and procedures for vibration testing and modal analysis are also described
Control of helicopter rotorblade aerodynamics
The results of a feasibility study of a method for controlling the aerodynamics of helicopter rotorblades using stacks of piezoelectric ceramic plates are presented. A resonant mechanism is proposed for the amplification of the displacements produced by the stack. This motion is then converted into linear displacement for the actuation of the servoflap of the blades. A design which emulates the actuation of the servoflap on the Kaman SH-2F is used to demonstrate the fact that such a system can be designed to produce the necessary forces and velocities needed to control the aerodynamics of the rotorblades of such a helicopter. Estimates of the electrical power requirements are also presented. A Small Business Innovation Research (SBIR) Phase 2 Program is suggested, whereby a bench-top prototype of the device can be built and tested. A collaborative effort between AEDAR Corporation and Kaman Aerospace Corporation is anticipated for future effort on this project
Investigating cardiovascular risk in premenopausal women on oral contraceptives: Systematic review with meta-analysis
BackgroundThe use of oral contraceptives (OCs) is associated with an increased risk of cardiovascular events such as arterial and venous thrombosis (VTE). Cardiovascular diseases (CVDs) are the leading cause of death worldwide, with low- and middle-income nations accounting for over three-quarter of CVD deaths. The aim of this systematic review is to provide a comprehensive synthesis of the available evidence on the link between OC use and CVD risk in premenopausal women and to further assess the role of geographic disparities in the reported prevalence of CVD risk in women on OCs.MethodsA comprehensive search of databases such as MEDLINE, Academic Search Complete, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Health Source: Nursing/Academic Edition was conducted, right from the inception to the present, by using the EBSCOhost search engine. The Cochrane Central Register of Clinical trials (CENTRAL) was also searched to augment relevant sources of information. OpenGrey, which is a repository of information providing open access to bibliographical references, was searched and the reference list of the selected studies was also scanned. The potential risk of bias of the included studies was assessed using the modified Downs and Black checklist. Data analysis was performed using the Review Manager (RevMan) version 5.3.ResultsWe included 25 studies that comprised 3,245 participants, of which 1,605 (49.5%) are OC users, while 1,640 (50.5%) are non-OC users. A total of 15 studies were included for meta-analysis, and the overall pooled estimates suggested a significant increase in the traditional cardiovascular risk variables [standardized mean difference (SMD) = 0.73, (0.46, 0.99) (Z = 5.41, p < 0.001)] and little to no difference in endothelial activation among OC users when compared with non-OC users [SMD = −0.11, (−0.81, 0.60) (Z = 0.30, p = 0.76)]. Europe [SMD = 0.03, (−0.21, 0.27), (Z = 0.25 p = 0.88)] had the least effect size, while North America had the highest effect size [SMD = 1.86, (−0.31, 4.04), (Z = 1.68 p = 0.09)] for CVD risk in OC users when compared with non-OC users.ConclusionThe use of OCs suggests a significant increase in the prevalence of traditional cardiovascular risk variables with little to no difference in the risk of endothelial dysfunction when compared with non-OC users, and the magnitude of CVD risks varies across different geographical regions.Registration and protocolThis systematic review was registered in the international prospective register of systematic reviews (PROSPERO) under the registration number: CRD42020216169
Gender influence on balance performances in the elderly
This study was carried out to investigate gender influence on balance performance of apparently healthy elderly using the Sharpened Romberg Test (SRT) for static balance and the Functional Reach Test (FRT) for dynamic balance assessments. One hundred and three (103) apparently healthy male and 100 apparently healthy female elderly subjects of age ranging from 60 to 74 years participated in this study. They had no history of neurologicaldeficits, postural hypotension, orthopaedics conditions or injury to the back and / or upper and lower extremities within the past five years.Descriptive statistics of range, means and standard deviation were used to analyze the physical characteristics and each of the two tests. The independent t-test was used to compare the balance performances in elderly males and females. The results showed that males performed significantly higher than females in FRT: ( 31.46 ± 12.34) and (24.00 ± 10.73) respectively. Males performed significantly higher than females in SRT in eyes opened (58.51 ± 4.43)and (56.58 ± 6.03) and eyes closed: (46.98 ± 14.89) and (42.59 ± 14.70) performances respectively.
It was concluded that males performed significantly better than females in both static and dynamic balance performances
Effect of cropping system and age of plant at harvest on tuber rot and performance of elite cassava varieties in derived savannah
Nutrient Intakes and Nutritional Status of Mothers and their Under-Five Children in a Rural Community of Oyo State, Nigeria
Malnutrition in sub-Saharan Africa contributes to high rates of childhood morbidity and mortality which make it a public health concern in Africa. This study assessed the nutrient intakes and nutritional status of mothers and their under-five children in a rural community of Oyo State, Nigeria. A total of 500 households with a mother and child pair were sampled using a multi-stage sampling procedure. Information on household socio-economic status, hygiene practices, breastfeeding practices and clinical observation for signs of malnutrition were collected using pre-tested semi-structured questionnaires by trained interviewers. Weight for age (WAZ), weight for height (WHZ), and height for age (HAZ) for underweight, wasting and stunting, respectively were calculated and assessed by Epi Info software using the NCHS/WHO international reference values. BMI (weight/height2) of mothers were also constructed from the measurements of mothers’ weights and heights. The waist/hip ratio of mothers was also determined. An interactive 24 h recall repeated for three days was used to obtain data on food and nutrient intakes of the women. Information on foods consumed was converted into quantitative data of nutrients using Food Composition Table. The result showed a high proportion (81%) of mothers ate three times daily while 14% ate twice and 5% ate more than thrice daily. The mean daily intakes of calcium, vitamins A, B6, B12, niacin, and folate were found to be inadequate compared with the Recommended Intakes. The WHR of the mothers indicated that majority had low risk. Most of the mothers (69.2%) were normal, underweight 9.6%, overweight 15.8% and obese 5.4%. About 37% of the children were stunted, 18% were underweight and 14.3% were wasted. BMI correlated negatively with age (r = -0.41; p <0.05), and positively with education (r = 0.22; p<0.05) and income (r = 0.45; p <0.05). Clinical observation revealed PEM prevalence in 12% children while eyes pallor and palm pallor were present in 15% and 20% respectively. The nutritional status of mothers and their under-five children is poor with respect to the overall food consumption and micronutrient intake. Consequently, nutrition programmes in this area should include effective measures to promote nutritional status of mothers and children
TIMP3 Is Reduced in Atherosclerotic Plaques From Subjects With Type 2 Diabetes and Increased by SirT1
Atherosclerosis is accelerated in subjects with type 2 diabetes by unknown mechanisms. We identified tissue inhibitor of metalloproteinase 3 (TIMP3), the endogenous inhibitor of A disintegrin and metalloprotease domain 17 (ADAM17) and other matrix metalloproteinases (MMPs), as a gene modifier for insulin resistance and vascular inflammation in mice. We tested its association with atherosclerosis in subjects with type 2 diabetes and identified Sirtuin 1 (SirT1) as a major regulator of TIMP3 expression
Effect of cropping system and age of plant at harvest on tuber rot and performance of elite cassava varieties in derived savannah
Devastated tuber rot disease among farmers prompted the evaluation of the elite improved varieties in the intercrop and the practice of delaying harvesting when there is glut in the market necessitated this study. Trial was carried out at the Federal University of Agriculture, Abeokuta between 2011 and 2014 to evaluate yield performance of 21 elite cassava varieties planted as sole crop verse intercropped and harvested at different age. The 2 x 21 x 3 factorial experiment was laid out in randomized complete block design and replicated three times. The tuber yield obtained from sole plot in 2011/2012 cropping season was significantly higher than intercrop whereas those of 2012/2014 cropping season were similar. Land Equivalent Ratio was above one in both cropping seasons indicating that the performance of the improved varieties in intercrop was efficient. The pooled mean tuber yield showed that TMS 30572, 92/0326, 95/0211, 01/1371, 00/0338, 01/0046, 00/0098, 01/1097, 01/0085, 98/0581 and 98/510 were among the top eight varieties. Harvesting could be delayed up to 15 months after planting to reduce tuber rot
The Pathogenic Potential of Campylobacter concisus Strains Associated with Chronic Intestinal Diseases
Campylobacter concisus has garnered increasing attention due to its association with intestinal disease, thus, the pathogenic potential of strains isolated from different intestinal diseases was investigated. A method to isolate C. concisus was developed and the ability of eight strains from chronic and acute intestinal diseases to adhere to and invade intestinal epithelial cells was determined. Features associated with bacterial invasion were investigated using comparative genomic analyses and the effect of C. concisus on host protein expression was examined using proteomics. Our isolation method from intestinal biopsies resulted in the isolation of three C. concisus strains from children with Crohn's disease or chronic gastroenteritis. Four C. concisus strains from patients with chronic intestinal diseases can attach to and invade host cells using mechanisms such as chemoattraction to mucin, aggregation, flagellum-mediated attachment, “membrane ruffling”, cell penetration and damage. C. concisus strains isolated from patients with chronic intestinal diseases have significantly higher invasive potential than those from acute intestinal diseases. Investigation of the cause of this increased pathogenic potential revealed a plasmid to be responsible. 78 and 47 proteins were upregulated and downregulated in cells infected with C. concisus, respectively. Functional analysis of these proteins showed that C. concisus infection regulated processes related to interleukin-12 production, proteasome activation and NF-κB activation. Infection with all eight C. concisus strains resulted in host cells producing high levels of interleukin-12, however, only strains capable of invading host cells resulted in interferon-γ production as confirmed by ELISA. These findings considerably support the emergence of C. concisus as an intestinal pathogen, but more significantly, provide novel insights into the host immune response and an explanation for the heterogeneity observed in the outcome of C. concisus infection. Moreover, response to infection with invasive strains has substantial similarities to that observed in the inflamed mucosa of Crohn's disease patients
Evidence-Based Guidelines for Cardiovascular Disease Prevention in Women
Significant advances in our knowledge about interventions to prevent cardiovascular disease (CVD) have occurred since publication of the first female-specific recommendations for preventive cardiology in 1999.1 Despite research-based gains in the treatment of CVD, it remains the leading killer of women in the United States and in most developed areas of the world.2–3 In the United States alone, more than one half million women die of CVD each year, exceeding the number of deaths in men and the next 7 causes of death in women combined. This translates into approximately 1 death every minute.2 Coronary heart disease (CHD) accounts for the majority of CVD deaths in women, disproportionately afflicts racial and ethnic minorities, and is a prime target for prevention.1–2 Because CHD is often fatal, and because nearly two thirds of women who die suddenly have no previously recognized symptoms, it is essential to prevent CHD.2 Other forms of atherosclerotic/thrombotic CVD, such as cerebrovascular disease and peripheral arterial disease, are critically important in women. Strategies known to reduce the burden of CHD may have substantial benefits for the prevention of noncoronary atherosclerosis, although they have been studied less extensively in some of these settings
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