724 research outputs found
An Implementable and Stabilizing Model Predictive Control Strategy for Inverted Pendulum-Like Behaved Systems
In control theory, the inverted pendulum is a class of dynamic systems widely used as a benchmarking for evaluating several control strategies. Such a system is characterized by an underactuated behavior. It is also nonlinear and presents open-loop unstable and integrating modes. These dynamic features make the control more difficult, mainly when the controller synthesis seeks to include constraints and the guarantee of stability of the closed-loop system. This chapter presents a stabilizing model predictive control (MPC) strategy for inverted pendulum-like behaved systems. It has an offset-free control law based on an only optimization problem (one-layer control formulation), and the Lyapunov stability of the closed-loop system is achieved by adopting an infinite prediction horizon. The controller feasibility is also assured by imposing a suitable set of slacked terminal constraints associated with the unstable and integrating states of the system. The effectiveness of the implementable and stabilizing MPC controller is experimentally demonstrated in a commercial-didactic rotary inverted pendulum prototype, considering both cases of stabilization of the pendulum in the upright position and the output tracking of the rotary arm angle
Dietary Patterns Associated with Alzheimer?s Disease and Related Chronic Disease Risk: A Review
The world’s population is growing older due to improved healthcare and nutrition. As a result, Alzheimer’s disease (AD) prevalence is rapidly increasing. The focus of the current research climate is shifting from understanding AD pathology and diagnosis to primary prevention and intervention strategies. Diet represents one potential intervention strategy accessible to all. Accumulating evidence suggests diet plays a major role in risk and development of AD and AD-related chronic diseases of the periphery like cardiovascular disease (CVD) and diabetes. This paper reviews studies that have explored the relationship between “a priori” dietary patterns, AD and AD-related chronic disease risk. The dietary patterns we will review are the healthy eating index, healthy diet indicator, recommended food score, and the Mediterranean diet (MeDi). Our review of the literature suggests a generally positive association between healthy diet patterns, AD and AD-related chronic disease risk; however the magnitude of the protective effect is modest in many studies. Consequently, we can only confidently conclude that the MeDi is associated with reduced AD risk, and further studies on the remaining indices need to be carried out. It is our opinion that a combination of dietary scores could predict overall dietary quality and chronic disease risk to a greater extent than one score individually. Analysis in multi-ethnic cohorts, investigating combinations of scores must be completed before firm conclusions can be reached on the ideal combination of scores. Obtaining further insight into the association between dietary patterns, AD and AD-related chronic disease risk may help in prioritizing public health efforts and provide a stronger basis for recommendations to improve dietary patterns
Intake of products containing anthocyanins, flavanols, and flavanones, and cognitive function: A narrative review
The purpose of this review is to examine human research studies published within the past 6 years which evaluate the role of anthocyanin, flavanol, and flavanone consumption in cognitive function, and to discuss potential mechanisms of action underlying any observed benefits. Evidence to date suggests the consumption of flavonoid-rich foods, such as berries and cocoa, may have the potential to limit, or even reverse, age-related declines in cognition. Over the last 6 years, the flavonoid subgroups of anthocyanins, flavanols, and flavanones have been shown to be beneficial in terms of conferring neuroprotection. The mechanisms by which flavonoids positively modulate cognitive function are yet to be fully elucidated. Postulated mechanisms include both direct actions such as receptor activation, neurotrophin release and intracellular signaling pathway modulation, and indirect actions such as enhancement of cerebral blood flow. Further intervention studies conducted in diverse populations with sufficient sample sizes and long durations are required to examine the effect of consumption of flavonoid groups on clinically relevant cognitive outcomes. As populations continue to focus on adopting healthy aging strategies, dietary interventions with flavonoids remains a promising avenue for future research. However, many questions are still to be answered, including identifying appropriate dosage, timeframes for intake, as well as the best form of flavonoids, before definitive conclusions can be drawn about the extent to which their consumption can protect the aging brain
Pulmonary alveolar proteinosis: a rare pulmonary toxicity of sirolimus.
Transpl Int. 2007 Mar;20(3):291-6.
Pulmonary alveolar proteinosis: a rare pulmonary toxicity of sirolimus.
Pedroso SL, Martins LS, Sousa S, Reis A, Dias L, Henriques AC, Sarmento AM, Cabrita A.
Nephrology Department, Hospital Geral de Santo António, Porto, Portugal. [email protected]
Abstract
The aim of our paper is to describe an unusual pulmonary toxicity of sirolimus (SRL) in a kidney transplant recipient. We present a 34-year-old woman with a second renal transplantation, complicated with steroid-resistant acute rejection and chronic allograft dysfunction. Two years after initiating SRL, she presented complaints of progressive dyspnoea, nonproductive cough, chest pain and low-grade fever of 1 month duration. She had chronic allograft nephropathy and slight elevation of lactic dehydrogenase levels. After exclusion of common reasons of this condition, a computed tomography (CT) of the thorax and bronchoscopy was performed, revealing ground-glass opacification with polygonal shapes on CT and an opaque appearance with numerous macrophages on bronchoalveolar lavage. The alveolar macrophages stained positive by Periodic acid-Schiff. Diagnosis of pulmonary alveolar proteinosis (PAP) was made and drug-induced toxicity was suspected. SRL was withdrawn with marked improvement in the patients' clinical and radiological status. PAP resolved within 3 months without further therapy. PAP is a very rare complication of SRL therapy with only a few cases described. Withdrawal of SRL with conversion to another immunosuppressant seems to be an appropriate procedure in this condition.
PMID: 17291222 [PubMed - indexed for MEDLIN
Personality characteristics are independently associated with prospective memory in the laboratory, and in daily life, among older adults
Prospective memory (PM) can deteriorate with age and adversely influence health behaviours. Research suggests that personality is related to PM in healthy young adults, but we know little about the role of personality in the PM amongst older adults. Community-dwelling older adults (N=152) completed the NEO Five-Factor Inventory-3 and PM measures. After adjusting for demographics and general cognition, higher neuroticism and lower levels of openness were independently associated with lower objectively-measured time- and event-based PM. Lower conscientiousness was the only personality predictor of self-reported everyday PM failures. Findings indicate that personality plays a role in PM functioning in the laboratory and daily life
The association between Alzheimer's Disease-Related markers and physical activity in cognitively normal older adults
Previous studies have indicated that physical activity may be beneficial in reducing the risk for Alzheimer's disease (AD), although the underlying mechanisms are not fully understood. The goal of this study was to evaluate the relationship between habitual physical activity levels and brain amyloid deposition and AD-related blood biomarkers (i.e., measured using a novel high-performance mass spectrometry-based assay), in apolipoprotein E (APOE) ε4 carriers and noncarriers. We evaluated 143 cognitively normal older adults, all of whom had brain amyloid deposition assessed using positron emission tomography and had their physical activity levels measured using the International Physical Activity Questionnaire (IPAQ). We observed an inverse correlation between brain amyloidosis and plasma beta-amyloid (Aβ)1−42 but found no association between brain amyloid and plasma Aβ1−40 and amyloid precursor protein (APP)669−711. Additionally, higher levels of physical activity were associated with lower plasma Aβ1−40, Aβ1−42, and APP669−711 levels in APOE ε4 noncarriers. The ratios of Aβ1−40/Aβ1−42 and APP669−711/Aβ1−42, which have been associated with higher brain amyloidosis in previous studies, differed between APOE ε4 carriers and non-carriers. Taken together, these data indicate a complex relationship between physical activity and brain amyloid deposition and potential blood-based AD biomarkers in cognitively normal older adults. In addition, the role of APOE ε4 is still unclear, and more studies are necessary to bring further clarification
Robust model-based indicators of regional differences in food-web structure in the Southern Ocean
Efforts to model marine food-webs are generally undertaken by small teams working separately on specific regions (<106 km2) and making independent decisions about how to deal with data gaps and uncertainties. Differences in these largely arbitrary decisions (which we call ‘model personality’) can potentially obscure true differences between regional food-webs or lead to spurious differences. Here we explore the influence of model personality on a comparison of four Southern Ocean regional food-web models. We construct alternative model versions which sequentially remove aspects of personality (alternative model ‘currencies’, schemes for aggregating organisms into functional groups, and energetic parameter values). These alternative versions preserve regional differences in biomass and feeding relationships. Variation in a set of model metrics that are insensitive to absolute biomass and production identifies multiple regional contrasts, a subset of which are robust to differences in model personality. These contrasts imply real differences in ecosystem structure which, in conjunction with differences in primary production and consumer biomass (spanning two and four orders of magnitude respectively), underpin differences in function. Existing regional models are therefore a useful resource for comparing ecosystem structure, function and response to change if comparative studies assess and report the influence of model personality
Follow-up plasma apolipoprotein E levels in the Australian Imaging, Biomarkers and Lifestyle Flagship Study of Ageing (AIBL) cohort
Introduction: Alzheimer's disease (AD) is a growing socioeconomic problem worldwide. Early diagnosis and prevention of this devastating disease have become a research priority. Consequently, the identification of clinically significant and sensitive blood biomarkers for its early detection is very important. Apolipoprotein E (APOE) is a well-known and established genetic risk factor for late-onset AD; however, the impact of the protein level on AD risk is unclear. We assessed the utility of plasma ApoE protein as a potential biomarker of AD in the large, well-characterised Australian Imaging, Biomarkers and Lifestyle Study of Ageing (AIBL) cohort.
Methods: Total plasma ApoE levels were measured at 18-month follow-up using a commercial bead-based enzyme-linked immunosorbent assay: the Luminex xMAP human apolipoprotein kit. ApoE levels were then analysed between clinical classifications (healthy controls, mild cognitive impairment (MCI) and AD) and correlated with the data available from the AIBL cohort, including but not limited to APOE genotype and cerebral amyloid burden.
Results: A significant decrease in ApoE levels was found in the AD group compared with the healthy controls. These results validate previously published ApoE protein levels at baseline obtained using different methodology. ApoE protein levels were also significantly affected, depending on APOE genotypes, with ε2/ε2 having the highest protein levels and ε4/ε4 having the lowest. Plasma ApoE levels were significantly negatively correlated with cerebral amyloid burden as measured by neuroimaging.
Conclusions: ApoE is decreased in individuals with AD compared with healthy controls at 18-month follow-up, and this trend is consistent with our results published at baseline. The influence of APOE genotype and sex on the protein levels are also explored. It is clear that ApoE is a strong player in the aetiology of this disease at both the protein and genetic levels
Data acquisition process for an intelligent decision support in gynecology and obstetrics emergency triage
Manchester Triage System is a reliable system of triage in the emergency department of a hospital. This system when applied to a specific patients’ condition such the pregnancy has several limitations. To overcome those limitations an alternative triage IDSS was developed in the MJD. In this approach the knowledge was obtained directly from the doctors’ empirical and scientific experience to make the first version of decision models. Due to the particular gynecological and/or obstetrics requests other characteristics had been developed, namely a system that can increase patient safety for women in need of immediate care and help low-risk women avoid high-risk care, maximizing the use of resources. This paper presents the arrival flowchart, the associated decisions and the knowledge acquisition cycle. Results showed that this new approach enhances the efficiency and the safety through the appropriate use of resources and by assisting the right patient in the right place.The work of Filipe Portela was supported by the grant SFRH/BD/70156/2010 from FC
Follicular cystitis in a dog: First case report described in Brazil
ABSTRACT A 2-year-old English bulldog presented history of recurrent lower urinary tract disease, refractory to treatment. The Complete Blood Count revealed lymphopenia, hyperproteinemia, and hyperglobulinemia, while urinalysis indicated leukocyturia and bacteriuria. On the abdominal ultrasound, the bladder had a focal wall thickening in its cranial portion, as well as irregular echogenicity and internal margins. A bladder surgical biopsy was performed, indicating the presence of follicular cystitis. Clinical signs disappeared after treatment with a combination of amoxicillin and clavulanic acid, NSAIDs, supplementation with cranberry extract associated with cat's claw (Uncaria tomentosa). Clinical follow-up 12 months after surgery showed remission at all clinical signs. Follicular cystitis in dogs was reported only once worldwide, this case report is the first in Brazil; thus, it may be considered in the differential diagnosis for patients with refractory and recurrent lower urinary tract disease
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