An experimental and theoretical study on the effect of sampling time delay on the stability of a PI position controller of a hydraulic cylinder

The stability properties of the feedback control of a hydraulic cylinder is analysed with an emphasis on the effect of the control delay due to the discrete sampling. A simple theoretical model is developed for low-load cases, i.e. if the forces acting of the piston are small compared to the pressure forces inside the cylinder. It is shown that in the case of a traditional PI controller, there is an upper and lower limit on the proportional gain corresponding to significantly different mechanisms of stability loss. It is shown that the frequency of the appearing oscillations at low proportional gains is one range smaller than that the sampling frequency. The theoretical results are confirmed by measurements

Wireless Multi-Sensor Networks for Smart Cities: A Prototype System with Statistical Data Analysis

As urbanization proceeds at an astonishing rate, cities have to continuously improve their solutions that affect the safety, health and overall wellbeing of their residents. Smart city projects worldwide build on advanced sensor, information and communication technologies to help dealing with issues like air pollution, waste management, traffic optimization, and energy efficiency. The paper reports about the prototype of a smart city initiative in Budapest which applies various sensors installed on the public lighting system and a cloud-based analytical module. While the installed wireless multi-sensor network gathers information about a number of stressors, the module integrates and statistically processes the data. The module can handle inconsistent, missing and noisy data and can extrapolate the measurements in time and space, namely, it can create short-term forecasts and smoothed maps, both accompanied by reliability estimates. The resulting database uses geometric representations and can serve as an information centre for public services.Comment: 9 pages, 8 figures, 3 tables, 27 reference

A krónikus kritikus végtagischaemia invazív kezelésének hosszú távú eredményei

INTRODUCTION AND AIM: Surgical tibial bypass for critical limb ischemia is associated with significant morbidity, mortality, and graft failure, whereas percutaneous angioplasty and stenting has promising results. The objective of this study was the investigation of the long term results of below-knee percutaneous angioplasty for restoring straight inline arterial flow in patients with critical limb ischemia. METHOD: The clinical and angiographic data of 281 consecutive patients with critical limb ischemia treated by PTA between 2008 and 2011 was evaluated in a prospective register. The aim of the revascularization was to achieve a straight inline flow to the wound with balloon angioplasty. Stent implantation was done in the case of recoil and flow limiting dissection. Primary end points were clinical success (relief of resting pain, healing of ulceration, limb survival) and major adverse events (death, myocardial infarction, major unplanned amputation, need for surgical revascularization, or major bleeding). Secondary end points were the angiographic result of the intervention, procedural data and consumption of angioplasty equipment. The impact of diabetic leg syndrome and the result of the angioplasty on the limb salvage was also investigated. We have analysed the impact of major amputation on long term mortality. RESULTS: Mean age of patients was 72.5 +/- 10.6 years and the follow-up period was 40.8 +/- 9.7 months. Technical success was reached in 255 (90.7%) of the patient's: 255 limbs straight inline flow with good angiographic result was restored to at least one tibial vessel. Balloon angioplasty, stent implantation and rotational atherectomy was performed in 278 (98.9%), 74 (26.3%) and 2 patients (0.7%). From clinical end points the rest pain was ceased in 56.6%, the ulcer and the gangrena was healed in 73.5% and 46.5%. The long term limb survival was 73.5%; 65.8% in diabetic and 89.6% in non-diabetic leg syndrome (p = 0.001). The major adverse events at long-term follow-up occured in 122 (43.8%) patients. Death occured in 57 (20.3%) of the patients during the long-term follow-up: 38 (13.5%) vs. 19 (6.8%) in diabetic vs. non-diabetic leg subgroup, respectively (p = 0.932). Long-term limb saving occured in 72.3% vs. 84.6% of the patients dependening the procedure was successful or unsuccessful (p = 0.225). CONCLUSION: Below-knee stent angioplasty for critical limb ischemia results in good clinical outcome, but the major adverse event rate is high. Diabetes mellitus is associated with a high rate of mortality and amputation. Orv. Hetil., 2017, 158(11), 418-425

The metabolic stress response: Adaptation to acute-, repeated- and chronic challenges in mice

There is a strong relationship between stress and metabolism. Because acute traumatic- and chronic stress events are often accompanied with metabolic pathophysiology, it is important to understand the details of the metabolic stress response. In this study we directly compared metabolic effects of acute stress with chronic repeated- and chronic unpredictable stress in mouse models. All types of adversities increased energy expenditure, chronic stress exposure decreased body weight gain, locomotor activity and differentially affected fuel utilization. During chronic exposure to variable stressors, carbohydrates were the predominant fuels, whereas fatty acids were catabolized in acutely and repeatedly restrained animals. Chronic exposure to variable stressors in unpredictable manner provoked anxiety. Our data highlight differences in metabolic responses to acute- repeated- and chronic stressors, which might affect coping behavior and underlie stress-induced metabolic and psychopathologies. © 202

Recruitment of Corticotropin-Releasing Hormone (CRH) Neurons in Categorically Distinct Stress Reactions in the Mouse Brain

Corticotropin-releasing hormone (CRH) neurons in the paraventricular hypothalamic nucleus (PVH) are in the position to integrate stress-related information and initiate adaptive neuroendocrine-, autonomic-, metabolic- and behavioral responses. In addition to hypophyseotropic cells, CRH is widely expressed in the CNS, however its involvement in the organization of the stress response is not fully understood. In these experiments, we took advantage of recently available Crh-IRES-Cre;Ai9 mouse line to study the recruitment of hypothalamic and extrahypothalamic CRH neurons in categorically distinct, acute stress reactions. A total of 95 brain regions in the adult male mouse brain have been identified as containing putative CRH neurons with significant expression of tdTomato marker gene. With comparison of CRH mRNA and tdTomato distribution, we found match and mismatch areas. Reporter mice were then exposed to restraint, ether, high salt, lipopolysaccha- ride and predator odor stress and neuronal activation was revealed by FOS immunocytochemistry. In addition to a core stress system, stressor-specific areas have been revealed to display activity marker FOS. Finally, activation of CRH neurons was detected by colocalization of FOS in tdTomato expressing cells. All stressors resulted in profound activation of CRH neurons in the hypothalamic paraventricular nucleus; however, a differential activation of pattern was observed in CRH neurons in extrahypothalamic regions. This comprehensive description of stress-related CRH neurons in the mouse brain provides a starting point for a systematic functional analysis of the brain stress system and its relation to stress-induced psychopathologies

Hypoglycemia-activated Hypothalamic Microglia Impairs Glucose Counterregulatory Responses

Abstract Glucose is a major fuel for the central nervous system and hypoglycemia is a significant homeostatic stressor, which elicits counterregulatory reactions. Hypothalamic metabolic- and stress-related neurons initiate these actions, however recruitment of glia in control such adaptive circuit remain unknown. Groups of fed- and fasted-, vehicle-injected, and fasted + insulin-injected male mice were compared in this study. Bolus insulin administration to fasted mice resulted in hypoglycemia, which increased hypothalamo-pituitary-adrenal (HPA) axis- and sympathetic activity, increased transcription of neuropeptide Y (Npy) and agouti-related peptide (Agrp) in the hypothalamic arcuate nucleus and activated IBA1+ microglia in the hypothalamus. Activated microglia were found in close apposition to hypoglycemia-responsive NPY neurons. Inhibition of microglia by minocycline increased counterregulatory sympathetic response to hypoglycemia. Fractalkine-CX3CR1 signaling plays a role in control of microglia during hypoglycemia, because density and solidity of IBA1-ir profiles was attenuated in fasted, insulin-treated, CX3CR1 KO mice, which was parallel with exaggerated neuropeptide responses and higher blood glucose levels following insulin administration. Hypoglycemia increased Il-1b expression in the arcuate nucleus, while IL-1a/b knockout mice display improved glycemic control to insulin administration. In conclusion, activated microglia in the arcuate nucleus interferes with central counterregulatory responses to hypoglycemia. These results underscore involvement of microglia in hypothalamic regulation of glucose homeostasis

Epidemiology and patients' self-reported knowledge of implantable medical devices: Results of a cross-sectional survey in Hungary.

BackgroundImplantable medical devices (IMDs) are medical instruments embedded inside the body. Well-informed and empowered patients living with IMDs are key players of improving IMD-related patient safety and health outcomes. However, little is known about IMD patients' epidemiology, characteristics, and current awareness levels. Our primary aim was to investigate the point and lifetime prevalence of patients living with IMDs. Patients' IMD-related knowledge and determinants of IMDs' impact on their life were also explored.MethodsAn online cross-sectional survey was conducted. Respondents' IMD history, whether they received instructions for use and IMD's overall impact on life were recorded by self-reports. Patients' knowledge about living with IMDs was assessed on visual analogue scales (VAS, 0-10). Shared decision-making was analyzed by the 9-item Shared Decision Making Questionnaire (SDM-Q-9). Descriptive statistics and subgroup comparisons between IMD wearers were performed for statistical differences. Significant determinants of IMD's overall impact on life were examined in linear regression analysis.ResultsIn the total sample (N = 1400, mean age 58.1 ±11.1; female 53.7%), nearly one third of respondents were living with IMD (30.9%; 433/1400). Among them, the most frequent IMDs were tooth implants (30.9%) and intraocular lens (26.8%). Mean knowledge VAS scores were similar (range: 5.5 ±3.8-6.5 ±3.2) but differences by IMD types were observed. Patients who received instructions for use or reported better impact on life indicated higher self-reported knowledge. Regression confirmed that patients' knowledge was significant predictor of IMD's impact on life, but this effect was overwritten by the SDM-Q-9.ConclusionsThis first comprehensive epidemiological study on IMDs provides basic data for public health strategy planning alongside the implementation of MDR. Improved self-perceived outcomes were associated with higher knowledge hence education of patients receiving IMD deserves consideration. We suggest to investigate further the role of shared decision-making on IMD's overall impact on patients' life in future prospective studies