Correction: Rheometry-on-a-chip: measuring the relaxation time of a viscoelastic liquid through particle migration in microchannel flows

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Instantaneous Assessment of Hedonic Olfactory Perception using Heartbeat Nonlinear Dynamics: A Preliminary Study

Emotional perception to hedonic olfactory stimuli is un- der direct control of the limbic system, whose dynam- ics is known to affect autonomic nervous system activity on cardiovascular control. Mainly due to methodologi- cal limitations, previous investigations failed to uncover specific trends in heartbeat dynamics between ultra short- time (i.e., lasting < 10s), pleasant and unpleasant olfac- tory stimuli. To this extent, in this study we computed in- stantaneous estimates from heartbeat series gathered from 32 healthy subjects (age: 26±2; 16M) undergoing hedo- nic olfactory elicitation. Each subject exhibited a simi- lar olfactory perception threshold, and scored five 5s stim- uli in terms of arousal and valence level using the self- assessment manikin test. We analyzed the heartbeat series using our recently proposed inhomogeneous point-process nonlinear framework, obtaining instantaneous estimates defined in the time (mean and standard deviation), fre- quency (power in the LF and HF bands, as well as LF/HF ratio), and nonlinear/complexity (bispectra, sample and approximate entropy, and Lyapunov exponent) domains. A feature set comprising average estimates within the 5s win- dows was taken as an input of a K-Nearest Neighborhood classification algorithm, whose cross-validation relied on a leave-one-subject-out procedure. Results demonstrate that our framework allows to finely characterize affective olfactory elicitation with an average recognition accuracy of 71.88%. Feature selection highlighted that the most dis- criminating power was contributed by instantaneous LF power, instantaneous Lyapunov exponents, and instanta- neous approximate entropy

Sweat analysis with a wearable sensing platform based on laser-induced graphene

The scientific community has shown increasing interest in laser scribing for the direct fabrication of conductive graphene-based tracks on different substrates. This can enable novel routes for the noninvasive analysis of biofluids (such as sweat or other noninvasive matrices), whose results can provide the rapid evaluation of a person's health status. Here, we present a wearable sensing platform based on laser induced graphene (LIG) porous electrodes scribed on a flexible polyimide sheet, which samples sweat through a paper sampler. The device is fully laser manufactured and features a two layer design with LIG-based vertical interconnect accesses. A detailed characterization of the LIG electrodes including pore size, surface groups, surface area in comparison to electroactive surface area, and the reduction behavior of different LIG types was performed. The bare LIG electrodes can detect the electrochemical oxidation of both uric acid and tyrosine. Further modification of the surface of the LIG working electrode with an indoaniline derivative [4-((4-aminophenyl)imino)-2,6-dimethoxycyclohexa-2,5-dien-1-one] enables the voltammetric measurement of pH with an almost ideal sensitivity and without interference from other analytes. Finally, electrochemical impedance spectroscopy was used to measure the concentrations of ions through the analysis of the sweat impedance. The device was successfully tested in a real case scenario, worn on the skin during a sports session. In vitro tests proved the non-cytotoxic effect of the device on the A549 cell line

Tribological behavior of shape-specific microplate-enriched synovial fluids on a linear two-axis tribometer

Nano- and micro-particles are being increasingly used to tune interfacial frictional properties in diverse applications, from friction modifiers in industrial lubrication to enhanced biological fluids in human osteoarthritic joints. Here, we assessed the tribological properties of a simulated synovial fluid enriched with non-spherical, poly lactic-co-glycolic acid (PLGA) microparticles (μPL) that have been previously demonstrated for the pharmacological management of osteoarthritis (OA). Three different μPL configurations were fabricated presenting a 20 μm 20 μm square base and a thickness of 5 μm (thin, 5H μPL), 10 μm (10H μPL), and 20 μm (cubical, 20H μPL). After extensive morphological and physicochemical characterizations, the apparent Young’s modulus of the μPL was quantified under compressive loading returning an average value of 6 kPa, independently of the particle morphology. Then, using a linear two-axis tribometer, the static (μs) and dynamic (μd) friction coefficients of the μPL-enriched simulated synovial fluid were determined in terms of particle configuration and concentration, varying from 0 (fluid only) to 6105 μPL/mL. The particle morphology had a modest influence on friction, possibly because the μPL were fully squeezed between two mating surfaces by a 5.8 N normal load realizing boundary-like lubrication conditions. Differently, friction was observed to depend on the dimensionless parameter , defined as the ratio between the total volume of the μPL enriching the simulated synovial fluid and the volume of the fluid itself. Both coefficients of friction were documented to grow with reaching a plateau of μs 0.4 and μd 0.15, already at&nbsp; 210-3. Future investigations will have to systematically analyze the effect of sliding velocity, normal load, and rigidity of the mating surfaces to elucidate in full the tribological behavior of μPL in the context of osteoarthritis

Longitudinal Bottom-Up Proteomics of Serum, Serum Extracellular Vesicles, and Cerebrospinal Fluid Reveals Candidate Biomarkers for Early Detection of Glioblastoma in a Murine Model

Glioblastoma Multiforme (GBM) is a brain tumor with a poor prognosis and low survival rates. GBM is diagnosed at an advanced stage, so little information is available on the early stage of the disease and few improvements have been made for earlier diagnosis. Longitudinal murine models are a promising platform for biomarker discovery as they allow access to the early stages of the disease. Nevertheless, their use in proteomics has been limited owing to the low sample amount that can be collected at each longitudinal time point. Here we used optimized microproteomics workflows to investigate longitudinal changes in the protein profile of serum, serum small extracellular vesicles (sEVs), and cerebrospinal fluid (CSF) in a GBM murine model. Baseline, pre-symptomatic, and symptomatic tumor stages were determined using non-invasive motor tests. Forty-four proteins displayed significant differences in signal intensities during GBM progression. Dysregulated proteins are involved in cell motility, cell growth, and angiogenesis. Most of the dysregulated proteins already exhibited a difference from baseline at the pre-symptomatic stage of the disease, suggesting that early effects of GBM might be detectable before symptom onset

On The Power of Tree Projections: Structural Tractability of Enumerating CSP Solutions

The problem of deciding whether CSP instances admit solutions has been deeply studied in the literature, and several structural tractability results have been derived so far. However, constraint satisfaction comes in practice as a computation problem where the focus is either on finding one solution, or on enumerating all solutions, possibly projected to some given set of output variables. The paper investigates the structural tractability of the problem of enumerating (possibly projected) solutions, where tractability means here computable with polynomial delay (WPD), since in general exponentially many solutions may be computed. A general framework based on the notion of tree projection of hypergraphs is considered, which generalizes all known decomposition methods. Tractability results have been obtained both for classes of structures where output variables are part of their specification, and for classes of structures where computability WPD must be ensured for any possible set of output variables. These results are shown to be tight, by exhibiting dichotomies for classes of structures having bounded arity and where the tree decomposition method is considered

Recovery of distal coronary flow reserve in LAD and LCx after Y-Graft intervention assessed by transthoracic echocardiography

<p>Abstract</p> <p>Background</p> <p>Y- graft (Y-G) is a graft formed by the Left Internal Mammary Artery (LIMA) connected to the Left Anterior Descending Artery (LAD) and by a free Right Internal Mammary Artery (RIMA) connected to LIMA and to a Marginal artery of Left Circumflex Artery (LCx). Aim of the work was to study the flow of this graft during a six months follow-up to assess whether the graft was able to meet the request of all the left coronary circulation, and to assess whether it could be done by evaluation of coronary flow reserve (CFR).</p> <p>Methods</p> <p>In 13 consecutive patients submitted to Y-G (13 men), CFR was measured in distal LAD and in distal LCx from 1 week after , every two months, up to six months after operation (a total of 8 tests for each patient) by means of transthoracic echocardiography (TTE) and Adenosine infusion (140 mcg/kg/min for 3-6 min). A Sequoia 256, Acuson-Siemens, was used. Contrast was used when necessary (Levovist 300 mg/ml solution at a rate of 0,5-1 ml/min). Max coronary flow diastolic velocity post-/pre-test ≥2 was considered normal CFR.</p> <p>Results</p> <p>Coronary arteriography revealed patency of both branches of Y-G after six months. Accuracy of TTE was 100% for LAD and 85% for LCx. Feasibility was 100% for LAD and 85% for LCx. CFR improved from baseline in LAD (2.21 ± 0.5 to 2.6 ± 0.5, p = 0.03) and in LCx (1.7 ± 1 to 2.12 ± 1, p = 0.05). CFR was under normal at baseline in 30% of patients <it>vs </it>8% after six months in LAD (p = 0.027), and in 69% of patients <it>vs </it>30% after six months in LCx (p = 0.066).</p> <p>Conclusion</p> <p>CFR in Y-G is sometimes reduced in both left territories postoperatively but it improves at six months follow-up. A follow-up can be done non-invasively by TTE and CFR evaluation.</p