10 research outputs found
Uso de los Conceptos Básicos de NXT-G 2.0 en la Construcción y Desarrollo de un Robot Seguidor de Línea
This paper shows the strategy of programming a line follower, from the application of basic mathematical formulas. Such formulas are translated into a basic graphic language, which enables testing of the strategy, a robot Lego Mindstorm NXT-G 2.0.En este artículo se muestra la estrategia de programación de un seguidor de línea, a partir de la aplicación de fórmulas matemáticas básicas. Las formulas son traducidas en un lenguaje gráfico elemental, que hace posible la experimentación de la estrategia, en un robot LEGO MINDSTOR
Endothelial Dysfunction: From Pathophysiology to Novel Therapeutic Approaches
Dear colleagues, This Special Issue, “Endothelial Dysfunction: From Pathophysiology to Novel Therapeutic Approaches”, focuses on the pathophysiology of endothelial dysfunction, new biomarkers for endothelial dysfunction related to cardiovascular disorders or tumors, and novel therapeutic approaches for endothelial dysfunctions. Vascular endothelium is an active tissue and plays a crucial role in the maintenance of vascular homeostasis. Chronic exposure to risk factors, such as hypertension, high cholesterolemia, or oxidative stress, induces endothelial dysfunctions and results in a loss of endothelial integrity, smooth muscle cell proliferation, and macrophage recruitment. The pathophysiology of endothelial dysfunction (ED) is complex and multi-factorial factors are involved, such as oxidative stress or chronic inflammation. The primary prevention of cardiovascular risk factors and endothelial dysfunctions, as well as the early detection of or molecular imaging techniques for endothelial dysfunction, helps to prevent the development of cardiovascular disorders. Novel therapeutic approaches or drug delivery systems for endothelial dysfunctions have had promising beneficial effects in preclinical or clinical levels by affecting the progression of atherosclerotic changes, tumor angiogenesis, and host–immune reactions near tumor environments
Right ventricular adaptation:in conditions of increased pressure load
Abnormal loading of the heart leads to the deterioration of heart function. For decades, clinical care and research focused on the left ventricle (LV), while knowledge about the right ventricle (RV) was left behind. This thesis describes (the regulation of) energy and remodeling processes of the abnormally loaded RV using studies in animal models and patients. We show that RV failure is associated with lack of relaxation of the heart muscle and reduced expression of genes involved in glycolysis (anaerobic metabolism of sugar), while meta-analysis shows that pressure load itself leads to increased RV sugar uptake and glycolysis. We were the first to identify that polyunsaturated fatty acids, especially cardiolipins, decrease in the pressure loaded RV. Cardiolipin is essential for adequate oxidative metabolism. However, oxidative metabolism was not yet affected at this point. Identifying the lipid profile may enable early identification of RV disease. This thesis also investigated whether previously identified regulatory processes in LV hypertrophy (enlarged heart muscle cells) also apply to the RV. This is not the case, which means that identified processes in the LV must also be investigated in the RV. Interestingly, in the LV itself these processes were affected in conditions of RV pressure load. Finally, we related biomarkers with type and degree of RV load, and RV remodeling and function in early stages of RV-disease. In conclusion, this thesis increases the knowledge of the abnormally loaded RV, which will support the development of tailored therapies
Separator fluid volume requirements in multi-infusion settings
INTRODUCTION. Intravenous (IV) therapy is a widely used method for the administration of medication in hospitals worldwide. ICU and surgical patients in particular often require multiple IV catheters due to incompatibility of certain drugs and the high complexity of medical therapy. This increases discomfort by painful invasive procedures, the risk of infections and costs of medication and disposable considerably. When different drugs are administered through the same lumen, it is common ICU practice to flush with a neutral fluid between the administration of two incompatible drugs in order to optimally use infusion lumens. An important constraint for delivering multiple incompatible drugs is the volume of separator fluid that is sufficient to safely separate them. OBJECTIVES. In this pilot study we investigated whether the choice of separator fluid, solvent, or administration rate affects the separator volume required in a typical ICU infusion setting. METHODS. A standard ICU IV line (2m, 2ml, 1mm internal diameter) was filled with methylene blue (40 mg/l) solution and flushed using an infusion pump with separator fluid. Independent variables were solvent for methylene blue (NaCl 0.9% vs. glucose 5%), separator fluid (NaCl 0.9% vs. glucose 5%), and administration rate (50, 100, or 200 ml/h). Samples were collected using a fraction collector until <2% of the original drug concentration remained and were analyzed using spectrophotometry. RESULTS. We did not find a significant effect of administration rate on separator fluid volume. However, NaCl/G5% (solvent/separator fluid) required significantly less separator fluid than NaCl/NaCl (3.6 ± 0.1 ml vs. 3.9 ± 0.1 ml, p <0.05). Also, G5%/G5% required significantly less separator fluid than NaCl/NaCl (3.6 ± 0.1 ml vs. 3.9 ± 0.1 ml, p <0.05). The significant decrease in required flushing volume might be due to differences in the viscosity of the solutions. However, mean differences were small and were most likely caused by human interactions with the fluid collection setup. The average required flushing volume is 3.7 ml. CONCLUSIONS. The choice of separator fluid, solvent or administration rate had no impact on the required flushing volume in the experiment. Future research should take IV line length, diameter, volume and also drug solution volumes into account in order to provide a full account of variables affecting the required separator fluid volume
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ESICM LIVES 2017 : 30th ESICM Annual Congress. September 23-27, 2017.
INTRODUCTION. Unplanned readmission to intensive care is highly
undesirable in that it contributes to increased variance in care,
disruption, difficulty in resource allocation and may increase length
of stay and mortality particularly if subject to delays. Unlike the ICU
admission from the ward, readmission prediction has received
relatively little attention, perhaps in part because at the point of ICU
discharge, full physiological information is systematically available to
the clinician and so it is expected that readmission should be largely
due to unpredictable factors. However it may be that there are
multidimensional trends that are difficult for the clinician to perceive
that may nevertheless be predictive of readmission.
OBJECTIVES. We investigated whether machine learning (ML)
techniques could be used to improve on the simple published SWIFT
score [1] for the prediction of unplanned readmission to ICU within
48 hours.
METHODS. We extracted systolic BP, pulse pressure, heart and
respiration rate, temperature, SpO2, bilirubin, creatinine, INR, lactate,
white cell count, platelet count, pH, FiO2, and total Glasgow Coma
Score from ICU stays of over 2000 adult patients from our hospital
electronic patient record system. We trained our own custom
multidimensional / time-sensitive algorithmic ML system to predict
failed discharges defined as either readmission or unexpected death
within 48 hours of discharge. We used 10-fold cross validation to assess performance. We also assessed the effect of augmenting our
system by transfer learning (TL) with 44,000 additional cases from
the MIMIC III database.
RESULTS. The SWIFT score performed relatively poorly with an
AUROC of around 0.6 which our ML system trained on local data was
also able to match. However when augmented with an additional
dataset by TL, the AUROC for the ML system improved statistically
and clinically significantly to over 0.7.
CONCLUSIONS. Machine learning is able to improve on predictors
based on simple multiple logistic regression. Thus there is likely to
be information in the trends and in combinations of variables. A
disadvantage with this technique is that ML approaches require large
amounts of data for training. However, ML approaches can be
improved by TL. Basing prediction models on locally derived data
augmented by TL is a potentially novel approach to generating tools
that customised to the institution yet can exploit the potential power
of ML algorithms.
REFERENCES
[1] Gajic O, Malinchoc M, Comfere TB, et al. The Stability and
Workload Index for Transfer score predicts unplanned intensive care
unit patient readmission: initial development and validation. Crit Care
Med. 2008;36(3):676–82.
Grant Acknowledgement
This work was internally funded
Smoking and Second Hand Smoking in Adolescents with Chronic Kidney Disease: A Report from the Chronic Kidney Disease in Children (CKiD) Cohort Study
The goal of this study was to determine the prevalence of smoking and second hand smoking [SHS] in adolescents with CKD and their relationship to baseline parameters at enrollment in the CKiD, observational cohort study of 600 children (aged 1-16 yrs) with Schwartz estimated GFR of 30-90 ml/min/1.73m2. 239 adolescents had self-report survey data on smoking and SHS exposure: 21 [9%] subjects had “ever” smoked a cigarette. Among them, 4 were current and 17 were former smokers. Hypertension was more prevalent in those that had “ever” smoked a cigarette (42%) compared to non-smokers (9%), p\u3c0.01. Among 218 non-smokers, 130 (59%) were male, 142 (65%) were Caucasian; 60 (28%) reported SHS exposure compared to 158 (72%) with no exposure. Non-smoker adolescents with SHS exposure were compared to those without SHS exposure. There was no racial, age, or gender differences between both groups. Baseline creatinine, diastolic hypertension, C reactive protein, lipid profile, GFR and hemoglobin were not statistically different. Significantly higher protein to creatinine ratio (0.90 vs. 0.53, p\u3c0.01) was observed in those exposed to SHS compared to those not exposed. Exposed adolescents were heavier than non-exposed adolescents (85th percentile vs. 55th percentile for BMI, p\u3c 0.01). Uncontrolled casual systolic hypertension was twice as prevalent among those exposed to SHS (16%) compared to those not exposed to SHS (7%), though the difference was not statistically significant (p= 0.07). Adjusted multivariate regression analysis [OR (95% CI)] showed that increased protein to creatinine ratio [1.34 (1.03, 1.75)] and higher BMI [1.14 (1.02, 1.29)] were independently associated with exposure to SHS among non-smoker adolescents. These results reveal that among adolescents with CKD, cigarette use is low and SHS is highly prevalent. The association of smoking with hypertension and SHS with increased proteinuria suggests a possible role of these factors in CKD progression and cardiovascular outcomes
Energy optimization for wireless sensor networks using hierarchical routing techniques
Philosophiae Doctor - PhDWireless sensor networks (WSNs) have become a popular research area that is widely
gaining the attraction from both the research and the practitioner communities due to their
wide area of applications. These applications include real-time sensing for audio delivery,
imaging, video streaming, and remote monitoring with positive impact in many fields such
as precision agriculture, ubiquitous healthcare, environment protection, smart cities and
many other fields. While WSNs are aimed to constantly handle more intricate functions
such as intelligent computation, automatic transmissions, and in-network processing, such
capabilities are constrained by their limited processing capability and memory footprint as
well as the need for the sensor batteries to be cautiously consumed in order to extend their
lifetime. This thesis revisits the issue of the energy efficiency in sensor networks by
proposing a novel clustering approach for routing the sensor readings in wireless sensor
networks. The main contribution of this dissertation is to 1) propose corrective measures to
the traditional energy model adopted in current sensor networks simulations that
erroneously discount both the role played by each node, the sensor node capability and
fabric and 2) apply these measures to a novel hierarchical routing architecture aiming at
maximizing sensor networks lifetime. We propose three energy models for sensor network:
a) a service-aware model that account for the specific role played by each node in a sensor
network b) a sensor-aware model and c) load-balancing energy model that accounts for the sensor node fabric and its energy footprint. These two models are complemented by a load balancing
model structured to balance energy consumption on the network of cluster heads
that forms the backbone for any cluster-based hierarchical sensor network. We present two
novel approaches for clustering the nodes of a hierarchical sensor network: a) a distanceaware
clustering where nodes are clustered based on their distance and the residual energy
and b) a service-aware clustering where the nodes of a sensor network are clustered
according to their service offered to the network and their residual energy. These
approaches are implemented into a family of routing protocols referred to as EOCIT
(Energy Optimization using Clustering Techniques) which combines sensor node energy
location and service awareness to achieve good network performance. Finally, building
upon the Ant Colony Optimization System (ACS), Multipath Routing protocol based on
Ant Colony Optimization approach for Wireless Sensor Networks (MRACO) is proposed
as a novel multipath routing protocol that finds energy efficient routing paths for sensor
readings dissemination from the cluster heads to the sink/base station of a hierarchical
sensor network. Our simulation results reveal the relative efficiency of the newly proposed
approaches compared to selected related routing protocols in terms of sensor network
lifetime maximization