A multi-layer monitoring system for clinical management of Congestive Heart Failure

BACKGROUND: Congestive Heart Failure (CHF) is a serious cardiac condition that brings high risks of urgent hospitalization and death. Remote monitoring systems are well-suited to managing patients suffering from CHF, and can reduce deaths and re-hospitalizations, as shown by the literature, including multiple systematic reviews. METHODS: The monitoring system proposed in this paper aims at helping CHF stakeholders make appropriate decisions in managing the disease and preventing cardiac events, such as decompensation, which can lead to hospitalization or death. Monitoring activities are stratified into three layers: scheduled visits to a hospital following up on a cardiac event, home monitoring visits by nurses, and patient's self-monitoring performed at home using specialized equipment. Appropriate hardware, desktop and mobile software applications were developed to enable a patient's monitoring by all stakeholders. For the first two layers, we designed and implemented a Decision Support System (DSS) using machine learning (Random Forest algorithm) to predict the number of decompensations per year and to assess the heart failure severity based on a variety of clinical data. For the third layer, custom-designed sensors (the Blue Scale system) for electrocardiogram (EKG), pulse transit times, bio-impedance and weight allowed frequent collection of CHF-related data in the comfort of the patient's home. We also performed a short-term Heart Rate Variability (HRV) analysis on electrocardiograms self-acquired by 15 healthy volunteers and compared the obtained parameters with those of 15 CHF patients from PhysioNet's PhysioBank archives. RESULTS: We report numerical performances of the DSS, calculated as multiclass accuracy, sensitivity and specificity in a 10-fold cross-validation. The obtained average accuracies are: 71.9% in predicting the number of decompensations and 81.3% in severity assessment. The most serious class in severity assessment is detected with good sensitivity and specificity (0.87 / 0.95), while, in predicting decompensation, high specificity combined with good sensitivity prevents false alarms. The HRV parameters extracted from the self-measured EKG using the Blue Scale system of sensors are comparable with those reported in the literature about healthy people. CONCLUSIONS: The performance of DSSs trained with new patients confirmed the results of previous work, and emphasizes the strong correlation between some CHF markers, such as brain natriuretic peptide (BNP) and ejection fraction (EF), with the outputs of interest. Comparing HRV parameters from healthy volunteers with HRV parameters obtained from PhysioBank archives, we confirm the literature that considers the HRV a promising method for distinguishing healthy from CHF patients

Model of thermo-optic nonlinear dynamics of photonic crystal cavities

The wavelength scale confinement of light offered by photonic crystal (PhC) cavities is one of the fundamental features on which many important on-chip photonic components are based, opening silicon photonics to a wide range of applications from telecommunications to sensing. This trapping of light in a small space also greatly enhances optical nonlinearities and many potential applications build on these enhanced light-matter interactions. In order to use PhCs effectively for this purpose it is necessary to fully understand the nonlinear dynamics underlying PhC resonators. In this work, we derive a first principles thermal model outlining the nonlinear dynamics of optically pumped silicon two-dimensional (2D) PhC cavities by calculating the temperature distribution in the system in both time and space. We demonstrate that our model matches experimental results well and use it to describe the behavior of different types of PhC cavity designs. Thus, we demonstrate the model's capability to predict thermal nonlinearities of arbitrary 2D PhC microcavities in any material, only by substituting the appropriate physical constants. This renders the model critical for the development of nonlinear optical devices prior to fabrication and characterization

Follow-Up of Coiled Cerebral Aneurysms at 3T: Comparison of 3D Time-of-Flight MR Angiography and Contrast-Enhanced MR Angiography

BACKGROUND AND PURPOSE: Our aim was to compare contrast-enhanced MR angiography (CE-MRA) and 3D time-of-flight (TOF) MRA at 3T for follow-up of coiled cerebral aneurysms. MATERIALS AND METHODS: Fifty-two patients treated with Guglielmi detachable coils for 54 cerebral aneurysms were evaluated at 3T MRA. 3D TOF MRA (TR/TE = 23/3.5; SENSE factor = 2.5) and CE-MRA by using a 3D ultrafast gradient-echo sequence (TR/TE = 5.9/1.8; SENSE factor = 3) enhanced with 0.1-mmol/kg gadobenate dimeglumine were performed in the same session. Source images, 3D maximum intensity projection, 3D shaded surface display, and/or 3D volume-rendered reconstructions were evaluated in terms of aneurysm occlusion/patency and artifact presence. RESULTS: In terms of clinical classification, the 2 MRA sequences were equivalent for 53 of the 54 treated aneurysms: 21 were considered fully occluded, whereas 16 were considered to have a residual neck and 16 were considered residually patent at follow-up MRA. The remaining aneurysm appeared fully occluded at TOF MRA but had a residual patent neck at CE-MRA. Visualization of residual aneurysm patency was significantly ( P = .001) better with CE-MRA compared with TOF MRA for 10 (31.3%) of the 32 treated aneurysms considered residually patent with both sequences. Coil artifacts were present in 5 cases at TOF MRA but in none at CE-MRA. No relationship was apparent between the visualization of patency and either the size of the aneurysm or the interval between embolization and follow-up. CONCLUSION: At follow-up MRA at 3T, unenhanced TOF and CE-MRA sequences are similarly effective at classifying coiled aneurysms as occluded or residually patent. However, CE-MRA is superior to TOF MRA for visualization of residual patency and is associated with fewer artifacts

The Impact of Sex and Arterial Stiffness Interactions on the Outcome after an Acute Ischemic Stroke: A Retrospective Cohort Study

Background/Objectives: Arterial stiffness (AS) is an independent predictor of cardiovascular events and is associated with a poor prognosis. While AS may represent a novel therapeutic target, recent evidence shows that it is sexually dimorphic. The aim of this study was to evaluate relative sex differences in arterial stiffness and their possible impact on the outcome of acute ischemic stroke. Methods: We retrospectively evaluated a cohort of adult patients with the following inclusion criteria: acute ischemic stroke, which occurred within 24 h from the onset of symptoms, confirmed through neuroimaging examinations, additional evaluations including extracranial and transcranial arterial ultrasound examinations, transthoracic echocardiography, a 12-lead resting ECG, and continuous 24 h in-hospital blood pressure monitoring. Based on the 24 h blood pressure monitoring, the following parameters were evaluated: systolic blood pressure, diastolic blood pressure, mean blood pressure, pulse pressure, and arterial stiffness index (ASI). The modified Rankin scale (mRS) was assessed at 90 days to evaluate the 3-month clinical outcome, defining an unfavorable outcome as an mRS score ≥ 3. To assess the factors associated with unfavorable outcomes, a stepwise logistic regression model was performed on the total sample size, and the analyses were replicated after stratifying by sex. Results: A total of 334 patients (176 males, 158 females) were included in the analysis. There was a significant sex-dependent impact of ASI on the 90-day unfavorable Rankin score (mRS score ≥ 3) as only men had a reduced likelihood of favorable outcomes with increasing arterial stiffness (OR:1.54, 95% CI: 1.06–2.23; P-interaction = 0.023). Conclusions: The influence of ASI on the 3-month functional outcome after acute ischemic stroke is at least in part sex-related, suggesting that, in males, higher ASI values are associated with a worse outcome

Development and characterization of passivation methods for microneedle-based biosensors

Microneedles (MN) are short, sharp structures that have the ability to painlessly pierce the stratum corneum, the outermost layer of the skin, and interface with the dermal interstitial fluid that lies beneath. Because the interstitial fluid is rich in biomarkers, microneedle-based biosensors have the potential to be used in a wide range of diagnostic applications. To act as an electrochemical sensor, the tip or the body of the MN must be functionalized, while the substrate areas are generally passivated to block any unwanted background interference that may occur outside of the skin. This work presents four different passivation techniques, based on the application of SiO2, polymethyl methacrylate (PMMA), an adhesive film, and varnish to the substrate areas. Optical, SEM and electrochemical measurements were performed to quantitatively assess the performance of each film. The data shows that whilst manual application of varnish provided the highest level of electrical isolation, the spin-coating of a 5 μm thick layer of PMMA is likely to provide the best combination of performance and manufacturability. Clinical Relevance— Substrate passivation techniques will improve the performance of microneedle-based non-invasive continuous monitoring systems

Comparing the safety and effectiveness of five leading new-generation devices for transcatheter aortic valve implantation: Twelve-month results from the RISPEVA study

Objectives. The management of severe aortic stenosis has been revolutionized by the introduction of transcatheter aortic valve implantation (TAVI), especially in patients at intermediate, high, or prohibitive surgical risk. There is uncertainty, however, regarding the comparative effectiveness and safety of contemporary TAVI devices. Methods. We queried detailed data from the ongoing national Italian TAVI registry and compared baseline features, procedural details, and 12-month outcomes of Acurate Neo (Boston Scientific), Evolut Pro/R (Medtronic), Lotus (Boston Scientific), Portico (Abbott Vascular), and Sapien/ Sapien S3 Ultra (Edward Lifesciences) transcatheter aortic valves. Several endpoints were collected and appraised, including the composite of death, stroke, myocardial infarction (MI), major bleeding, major vascular complication, surgical aortic valve replacement and transcatheter aortic valve reimplantation, which were deemed major adverse events (MAEs). Results. A total of 1976 patients were included, with 234 treated with Acurate, 703 with Evolut, 151 with Lotus, 347 with Portico, and 541 with Sapien. Twelve-month events were not significantly different among the 5 devices, including death (P=.29) and MAE (P=.21), with the notable exception of major vascular complications, which were more common with Acurate and Sapien (P<.001) and permanent pacemaker implantation, which was more frequent with Lotus and Evolut (P<.001). Differences in MAE were more pronounced in women and subjects with prior cardiac surgery, with the lowest event rates in the Evolut group. Propensity-score adjusted analysis suggested that Acurate, Evolut, Portico, and Sapien were all associated with similarly favorable results, whereas adverse events were more evident with Lotus (P<.05). Conclusion. Leading current-generation TAVI devices offer similarly favorable results at mid-term follow-up

Input Clinical Parameters for Cardiac Heart Failure Characterization Using Machine Learning

Congestive Heart Failure (CHF) is a serious chronic cardiac condition that brings high risk of urgent hospi- talization and could lead to death. In this work we show how all the input clinical parameters for classifying CHF using Machine Learning can be acquired. The requested input are Blood Pres- sure, Heart Rate, Brain Natriuretic Peptide, Electrocardio- gram, Blood Oxygen Saturation, Height, Weight and Ejection Fraction. The next step will be designing a novel device and con- necting it to our Machine Learning classifier. A particular at- tention will be put to the assessment of electromagnetic compat- ibility (EMC) with other devices, taking into account that this new device will be used in many different settings (home, out- door, etc.

Cryo-EM structures of an insecticidal Bt toxin reveal its mechanism of action on the membrane

Insect pests are a major cause of crop losses worldwide, with an estimated economic cost of $470 billion annually. Biotechnological tools have been introduced to control such insects without the need for chemical pesticides; for instance, the development of transgenic plants harbouring genes encoding insecticidal proteins. The Vip3 (vegetative insecticidal protein 3) family proteins from Bacillus thuringiensis convey toxicity to species within the Lepidoptera, and have wide potential applications in commercial agriculture. Vip3 proteins are proposed to exert their insecticidal activity through pore formation, though to date there is no mechanistic description of how this occurs on the membrane. Here we present cryo-EM structures of a Vip3 family toxin in both inactive and activated forms in conjunction with structural and functional data on toxin–membrane interactions. Together these data demonstrate that activated Vip3Bc1 complex is able to insert into membranes in a highly efficient manner, indicating that receptor binding is the likely driver of Vip3 specificity

Polarization Control in Integrated Graphene-Silicon Quantum Photonics Waveguides

We numerically investigated the use of graphene nanoribbons placed on top of silicon-on-insulator (SOI) strip waveguides for light polarization control in silicon photonic-integrated waveguides. We found that two factors mainly affected the polarization control: the graphene chemical potential and the geometrical parameters of the waveguide, such as the waveguide and nanoribbon widths and distance. We show that the graphene chemical potential influences both TE and TM polarizations almost in the same way, while the waveguide width tapering enables both TE-pass and TM-pass polarizing functionalities. Overall, by increasing the oxide spacer thickness between the silicon waveguide and the top graphene layer, the device insertion losses can be reduced, while preserving a high polarization extinction ratio