Search results for "Biomedical"

Radiation-engineered functionalized nanogels as platform for biomedical nanocarriers and bio-hybrid, hierarchically assembled nanostructures

2011

Radiation technologies can be considered as choice methodologies for the creation of new functional materials at the nanoscale, the challenge being now the integration of these and other novel nanomaterials into new materials and products. The possibility of generating nanoscalar PVP-based hydrogels particles, with reactive functional groups for subsequent bioconjugation, using industrial type accelerators has been demonstrated. These functional nanoparticles are under evaluation as nanocarriers for targeted release of drugs, but can also be considered as useful building blocks for the assembly of nanostructured materials with controlled architecture. In particular, molecular recognition st…

Biopolyester-based systems containing naturally occurring compounds suitable for biomedical devices

2016

Bivariate nonlinear prediction to quantify the strength of complex dynamical interactions in short-term cardiovascular variability.

2005

A nonlinear prediction method for investigating the dynamic interdependence between short length time series is presented. The method is a generalization to bivariate prediction of the univariate approach based on nearest neighbor local linear approximation. Given the input and output series x and y, the relationship between a pattern of samples of x and a synchronous sample of y was approximated with a linear polynomial whose coefficients were estimated from an equation system including the nearest neighbor patterns in x and the corresponding samples in y. To avoid overfitting and waste of data, the training and testing stages of the prediction were designed through a specific out-of-sampl…

Real-time estimation of plasma insulin concentration from continuous glucose monitor measurements

2015

Continuous glucose monitors can measure interstitial glucose concentration in real time for closed-loop glucose control systems, known as artificial pancreas. These control systems use an insulin feedback to maintain plasma glucose concentration within a narrow and safe range, and thus to avoid health complications. As it is not possible to measure plasma insulin concentration in real time, insulin models have been used in literature to estimate them. Nevertheless, the significant interand intra-patient variability of insulin absorption jeopardizes the accuracy of these estimations. In order to reduce these limitations, our objective is to perform a real-time estimation of plasma insulin co…

Extensive Assessment of Blood Glucose Monitoring During Postprandial Period and Its Impact on Closed-Loop Performance.

2017

[EN] Background: Closed-loop (CL) systems aims to outperform usual treatments in blood glucose control and continuous glucose monitors (CGM) are a key component in such systems. Meals represents one of the main disturbances in blood glucose control, and postprandial period (PP) is a challenging situation for both CL system and CGM accuracy. Methods: We performed an extensive analysis of sensor¿s performance by numerical accuracy and precision during PP, as well as its influence in blood glucose control under CL therapy. Results: During PP the mean absolute relative difference (MARD) for both sensors presented lower accuracy in the hypoglycemic range (19.4 ± 12.8%) than in other ranges (12.2…

Properties of erythrocyte light refraction in diabetic patients.

2001

Since hyperglycaemia changes the erythrocyte cell membrane fluidity and impairs cell deformity, our goal was to characterize hemoglobin and red blood cell (RBC) light refractive property changes in diabetic patients. Microscopic investigation was carried out on intact and fixed RBCs. To determine the refractive index (RI): smears of peripheral blood were air dried and fixed for 3 min in methanol. Mixtures of polyvinylpyrolidine and buffer of different pH (1:1) were used as embedding media. Intact RBCs were mixed with a buffered embedding medium, placed on a slide and overlaid with a coverslip. Interference microscopy was used for RI measurements at 18 different pH (pH=2-13). The results sho…

Noncontact speckle-based optical sensor for detection of glucose concentration using magneto-optic effect

2016

We experimentally verify a speckle-based technique for noncontact measurement of glucose concentration in the bloodstream. The final device is intended to be a single wristwatch-style device containing a laser, a camera, and an alternating current (ac) electromagnet generated by a solenoid. The experiments presented are performed in vitro as proof of the concept. When a glucose substance is inserted into a solenoid generating an ac magnetic field, it exhibits Faraday rotation, which affects the temporal changes of the secondary speckle pattern distributions. The temporal frequency resulting from the ac magnetic field was found to have a lock-in amplification role, which increased the observ…

PsychDT Working Group

2015

Background: Diabetes technology is a cornerstone of diabetes management in the 21st century, with advances in available devices over recent years playing a central role in the way that health care has progressed. Psychosocial interventions have been shown to have a positive impact on glycemic control, reduce psychological distress and reduce costs of health care. Addressing and improving psychosocial outcomes that complement biomedical improvements and looking to the future are crucial to enhance patient acceptance of artificial pancreas (AP) systems. Methods: To achieve closer collaboration and comparability across different AP research trials, a working group was established. Results: Exi…

A novel flash glucose monitoring system in patients with diabetes mellitus type 1 and 2: which are the pieces of evidence for payer decision-makers?

2018

A rigorous health technology assessment is necessary to evaluate a new technology. However, healthcare regulatory agencies have less restrictive rules about medical devices, despite some recent warnings about this relevant matter. The evaluation should have at least two key issues, which require attention. The first one is its effectiveness, and the second one is its economic sustainability. In this paper, we deal with a novel glucose-sensing technology as a case study to examine the matter in depth. An evidence-based point of view is used to highlight this important issue.

Intraportal transplantation of allogenic pancreatic islets encapsulated in barium alginate beads in diabetic rats.

2003

The survival of microencapsulated islets transplanted into the unmodified peritoneal cavity is limited, even if capsular overgrowth is restricted to a minimum, due to an insufficient oxygen supply to the islets. Therefore, research efforts should focus on finding or creating a transplantation site, which permits a closer contact between the encapsulated islets and the blood. For this reason, the liver could be an interesting candidate. The aim of the present study was to test the hypothesis that the intraportal transplantation of allogenic islets encapsulated in small-sized barium alginate beads is safe and succeeds to induce normoglycemia in diabetic rats. The intraportal transplantation o…