Development of a Disposable Gold Electrodes-Based Sensor for Electrochemical Measurements of cDNA Hybridization

AbstractThis work deals with the development of a disposable electrochemical biosensor for the specific detection of short DNA sequences. The sensor is an amperometric transducer with three planar electrodes, comprising a working, a counter and a pseudo-reference electrode, all made of a gold layer over a polycarbonate substrate. For the development of the genosensor, the working electrode was modified using thiol-tethered 33-mer DNA probe by chemisorptions, in a concentration range from 0.1 μM to 5 μM. Immobilization of ssDNA on gold surface was monitored with electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) in Fe(CN)64−/13− and Ruthenium(II)/(III) solutions. The time dependence of ssDNA probe immobilization was also studied. The hybridization detection is then compared with EIS and DPV measurements

Alignment transition in a nematic liquid crystal due to field-induced breaking of anchoring

We report on the alignment transition of a nematic liquid crystal from initially homeotropic to quasi-planar due to field-induced anchoring breaking. The initial homeotropic alignment is achieved by Langmuir-Blodgett monolayers. In this geometry the anchoring strength can be evaluated by the Frederiks transition technique. Applying an electric field above a certain threshold provokes turbulent states denoted DSM1 and DSM2. While DSM1 does not affect the anchoring, DSM2 breaks the coupling between the surface and the liquid crystal: switching off the field from a DSM2 state does not immediately restore the homeotropic alignment. Instead, we obtain a quasi-planar metastable alignment. The cell thickness dependence for the transition is related to theComment: 7 pages, LaTeX2e article, 4 figures, 7 EPS files, added references, accepted for publication in Europhysics Letter

Event-based, 6-DOF Camera Tracking from Photometric Depth Maps

Event cameras are bio-inspired vision sensors that output pixel-level brightness changes instead of standard intensity frames. These cameras do not suffer from motion blur and have a very high dynamic range, which enables them to provide reliable visual information during high-speed motions or in scenes characterized by high dynamic range. These features, along with a very low power consumption, make event cameras an ideal complement to standard cameras for VR/AR and video game applications. With these applications in mind, this paper tackles the problem of accurate, low-latency tracking of an event camera from an existing photometric depth map (i.e., intensity plus depth information) built via classic dense reconstruction pipelines. Our approach tracks the 6-DOF pose of the event camera upon the arrival of each event, thus virtually eliminating latency. We successfully evaluate the method in both indoor and outdoor scenes and show that—because of the technological advantages of the event camera—our pipeline works in scenes characterized by high-speed motion, which are still unaccessible to standard cameras

Precise Bearing Angle Measurement Based on Omnidirectional Conic Sensor and Defocusing

Recent studies on multi-robot localization have shown that the uncertainty of robot location may be considerably reduced by optimally fusing odometry and the relative angles of sight (bearing) among the team members. However, the latter requires the capability for each robot of detecting the other members up to large distances and wide field of view. Furthermore, robustness and precision in estimating the relative angle of sight is of high importance. In this paper we show how all of the these requirements may be achieved by employing an omnidirectional sensor made up of a conic mirror and a simple webcam. We use different colored lights to distinguish the robots and optical defocusing to identify the lights. We show that defocusing increases the detection range up to several meters, compensating the decay of resolution related to the omnidirectional view, without losing robustness and precision. To allow a real time implementation of light tracking, we use a recent tree-based union find technique for color segmentation and region merging. We also present a self-calibration technique based on an Extended Kalman Filter to derive the intrinsic parameters of the robot-sensor system. The performance of the approach is shown through experimental results

Sensitive methods for estimating the anchoring strength of nematic liquid crystals on Langmuir-Blodgett monolayers of fatty acids

The anchoring of the nematic liquid crystal N-(p-methoxybenzylidene)-p-butylaniline (MBBA) on Langmuir-Blodgett monolayers of fatty acids (COOHC$_{n}$H$_{2n+1}$) was studied as a function of the length of the fatty acid alkyl chains, $n$ ($n = 15, 17, 19, 21$). The monolayers were deposited onto ITO-coated glass plates which were used to assemble sandwich cells of various thickness that were filled with MBBA in the nematic phase. The mechanism of relaxation from the flow-induced quasi-planar to the surface-induced homeotropic alignment was studied for the four decreases linearly with increasing the length of the alkyl chains $n$ which suggests that the Langmuir-Blodgett film plays a role in the phenomenon. This fact was confirmed by a sensitive estimation of the anchoring strength of MBBA on the fatty acid monolayers after anchoring breaking which takes place at the transition between two electric-field--induced turbulent states, denoted as DSM1 and DSM2. It was found that the threshold electric field for the anchoring breaking, which can be considered as a measure of the anchoring strength, also decreases linearly as $n$ increases. Both methods thus possess a high sensitivity in resolving small differences in anchoring strength. In cells coated with mixed Langmuir-Blodgett monolayers of two fatty acids ($n=15$ and $n=17$) a maximum of the relaxation speed was observed when the two acids were present in equal amount. This observation homeotropic cells by changing the ratio between the components of the surfactant film.Comment: LaTeX article, 20 pages, 15 figures, 17 EPS files. 1 figure added, references moved. Submitted to Phys. Rev.

Has covid-19 delayed the diagnosis and worsened the presentation of type 1 diabetes in children?

OBJECTIVE To evaluate whether the diagnosis of pediatric type 1 diabetes or its acute complications changed during the early phase of the coronavirus disease 2019 (COVID-19) pandemic in Italy. RESEARCH DESIGN AND METHODS This was a cross-sectional, web-based survey of all Italian pediatric diabetes centers to collect diabetes, diabetic ketoacidosis (DKA), and COVID-19 data in patients presenting with new-onset or established type 1 diabetes between 20 February and 14 April in 2019 and 2020. RESULTS Fifty-three of 68 centers (77.9%) responded. There was a 23% reduction in new diabetes cases in 2020 compared with 2019. Among those newly diagnosed patients who presented in a state of DKA, the proportion with severe DKA was 44.3% in 2020 vs. 36.1% in 2019 (P 5 0.03). There were no differences in acute complications. Eight patients with asymptomatic or mild COVID-19 had laboratory-confirmed severe acute respiratory syndrome coronavirus 2. CONCLUSIONS The COVID-19 pandemic might have altered diabetes presentation and DKA severity. Preparing for any “second wave” requires strategies to educate and reassure parents about timely emergency department attendance for non–COVID-19 symptoms

Rethinking carbohydrate intake and time in range in children and adolescents with type 1 diabetes

none15The aim of this study was to evaluate the association between macronutrient intake and time in range (TIR) of 70–180 mg/dL in children and adolescents with type 1 diabetes (T1D). A multi-center study recruited patients with T1D using continuous glucose monitoring (CGM) between January 2019 and January 2020 from centers across Italy. Diet intake was recorded using three-day weighed food diaries. Nutrients were evaluated as percentages of total intake. TIR was considered at target if the percentage of readings was higher than 70%. Clinical and nutritional factors associated with TIR at target were analyzed using multiple correspondence analysis and multiple logistic regression. Data from 197 participants (53% male, median age 11.6 years, median HbA1c 55.2 mmol/mol, median TIR 60%) were analyzed. Macronutrient intake was 45.9% carbohydrates, 16.9% protein, 37.3% fat, and 13.1 g/day fiber (median values). TIR > 70% was observed in 28% of participants; their diet contained more protein (17.6%, p = 0.015) and fiber (14.4 g/day, p = 0.031) than those not at target. The probability of having a TIR > 70% was significantly higher with 40–44% consumption of carbohydrates compared with 45–50% consumption of carbohydrates and with the use of a carbohydrate counting system. Based on these results, a five percent reduction in the percentage of carbohydrate intake can help children and adolescents with T1D achieve the goal of a TIR > 70%. Both a lower and higher percentage of carbohydrate intake appears to reduce the probability of reaching the target TIR > 70%. These results require validation in other populations before being used in clinical practice.openCherubini V.; Marino M.; Marigliano M.; Maffeis C.; Zanfardino A.; Rabbone I.; Giorda S.; Schiaffini R.; Lorubbio A.; Rollato S.; Iannilli A.; Iafusco D.; Scaramuzza A.E.; Bowers R.; Gesuita R.Cherubini, V.; Marino, M.; Marigliano, M.; Maffeis, C.; Zanfardino, A.; Rabbone, I.; Giorda, S.; Schiaffini, R.; Lorubbio, A.; Rollato, S.; Iannilli, A.; Iafusco, D.; Scaramuzza, A. E.; Bowers, R.; Gesuita, R