Our understanding of the fate and distribution of micro- and nano- plastics in the marine environment is limited by the intrinsic difficulties of the techniques currently used for the detection, ...quantification, and chemical identification of small particles in liquid (light scattering, vibrational spectroscopies, and optical and electron microscopies). Here we introduce Raman Tweezers (RTs), namely optical tweezers combined with Raman spectroscopy, as an analytical tool for the study of micro- and nanoplastics in seawater. We show optical trapping and chemical identification of sub-20 μm plastics, down to the 50 nm range. Analysis at the single particle level allows us to unambiguously discriminate plastics from organic matter and mineral sediments, overcoming the capacities of standard Raman spectroscopy in liquid, intrinsically limited to ensemble measurements. Being a microscopy technique, RTs also permits one to assess the size and shapes of particles (beads, fragments, and fibers), with spatial resolution only limited by diffraction. Applications are shown on both model particles and naturally aged environmental samples, made of common plastic pollutants, including polyethylene, polypropylene, nylon, and polystyrene, also in the presence of a thin eco-corona. Coupled to suitable extraction and concentration protocols, RTs have the potential to strongly impact future research on micro and nanoplastics environmental pollution, and enable the understanding of the fragmentation processes on a multiscale level of aged polymers.
Postoperative hypocalcemia is the most frequent complication of total thyroidectomy. It may have a delayed onset, and therefore delays the discharge from the hospital, requiring calcium replacement ...therapy to alleviate clinical symptoms. During a 7-month period, 2,631 consecutive patients undergoing primary or completion thyroidectomy were prospectively followed up and underwent analysis regarding postoperative hypoparathyroidism. Data were prospectively collected by questionnaires from 39 Italian endocrine surgery units affiliated to the Italian Endocrine Surgery Units Association (Club delle Unità di EndocrinoChirurgia—UEC), where thyroid surgery is routinely performed. The incidence of hypoparathyroidism was 28.8 % (757 patients), including transient hypocalcemia (27.9 %—734 patients) and permanent hypocalcemia (0.9 %—23 patients). The rate of asymptomatic hypocalcemia was 70.80 %. The incidence of permanent hypocalcemia was higher in the symptomatic hypocalcemia group (7.5 %) than in asymptomatic one (1.5 %). Female patients experienced a transient postoperative hypocalcemia more frequently than male patients (29.7 and 21.2 %, respectively;
p
< 0.0001). The percentage developing hypocalcemia in patients in which parathyroid glands were intraoperatively identified and preserved was higher than in the patients in which the identification of parathyroid glands was not achieved (29.2 vs. 18.7 %,
p
< 0.01). This prospective study confirmed the main risk factors for postoperative hypocalcemia: thyroid cancer, nodal dissection, and female gender. It farther showed that identifying parathyroids has an important role to prevent permanent hypocalcemia though with a higher risk of transient hypocalcemia. A suitable informed consent should especially emphasize the importance of some primary factors in increasing the risk of hypocalcemia after thyroid surgery.
In this article we show that linear nanoantennas can be used as shared substrates for surface-enhanced Raman and infrared spectroscopy (SERS and SEIRS, respectively). This is done by engineering the ...plasmonic properties of the nanoantennas, so to make them resonant in both the visible (transversal resonance) and the infrared (longitudinal resonance), and by rotating the excitation field polarization to selectively take advantage of each resonance and achieve SERS and SEIRS on the same nanoantennas. As a proof of concept, we have fabricated gold nanoantennas by electron beam lithography on calcium difluoride (1–2 μm long, 60 nm wide, 60 nm high) that exhibit a transverse plasmonic resonance in the visible (640 nm) and a particularly strong longitudinal dipolar resonance in the infrared (tunable in the 1280–3100 cm–1 energy range as a function of the length). SERS and SEIRS detection of methylene blue molecules adsorbed on the nanoantenna’s surface is accomplished, with signal enhancement factors of 5 × 102 for SERS (electromagnetic enhancement) and up to 105 for SEIRS. Notably, we find that the field enhancement provided by the transverse resonance is sufficient to achieve SERS from single nanoantennas. Furthermore, we show that by properly tuning the nanoantenna length the signals of a multitude of vibrational modes can be enhanced with SEIRS. This simple concept of plasmonic nanosensor is highly suitable for integration on lab-on-a-chip schemes for label-free chemical and biomolecular identification with optimized performances.
Peripheral nerve injury is a serious problem affecting signiifcantly patients’ life. Autografts are the“gold standard” used to repair the injury gap, however, only 50% of patients fully recover from ...the trauma. Artiifcial conduits are a valid alternative to repairing peripheral nerve. They aim at conifning the nerve environment throughout the regeneration process, and providing guidance to axon outgrowth. Biocompatible materials have been carefully designed to reduce inlfamma-tion and scar tissue formation, but modiifcations of the inner lumen are still required in order to optimise the scaffolds. Biomicking the native neural tissue with extracellular matrix ifllers or coatings showed great promises in repairing longer gaps and extending cell survival. In addition, extracellular matrix molecules provide a platform to further bind growth factors that can be released in the system over time. Alternatively, conduit ifllers can be used for cell transplantation at the injury site, reducing the lag time required for endogenous Schwann cells to proliferate and take part in the regeneration process. This review provides an overview on the importance of ex-tracellular matrix molecules in peripheral nerve repair.
Optical forces are used to aggregate plasmonic nanoparticles and create SERS-active hot spots in liquid. When biomolecules are added to the nanoparticles, high sensitivity SERS detection can be ...accomplished. Here, we pursue studies on Bovine Serum Albumin (BSA) detection, investigating the BSA-nanorod aggregations in a range from 100 µM to 50 nM by combining light scattering, plasmon resonance and SERS, and correlating the SERS signal with the concentration. Experimental data are fitted with a simple model describing the optical aggregation process. We show that BSA-nanorod complexes can be optically printed on non-functionalized glass surfaces, designing custom patterns stable with time. Furthermore, we demonstrate that this methodology can be used to detect catalase and hemoglobin, two Raman resonant biomolecules, at concentrations of 10 nM and 1 pM, respectively, i.e., well beyond the limit of detection of BSA. Finally, we show that nanorods functionalized with specific aptamers can be used to capture and detect Ochratoxin A, a fungal toxin found in food commodities and wine. This experiment represents the first step towards the addition of molecular specificity to this novel biosensor strategy.
Classification is one of the most popular topics in healthcare and bioinformatics, especially in relation to arrhythmia detection. Arrhythmias are irregularities in the rate or rhythm of the ...heartbeat which, in some cases, may occur sporadically in a subject’s daily life. To capture these infrequent events, a Holter device is usually employed to record long-term ECG data. Therefore, the automatic recognition of abnormal heartbeats from a large amount of ECG data is an important and essential task. In the last two decades, a huge number of methods have been proposed to address the problem of ECG beat classification. At the same time, deep learning has advanced rapidly since the early 2000s and now demonstrates a state-of-the-art performance in various fields. In this paper, we propose a novel deep learning approach for ECG beat classification. We have conducted the experiments on the well-known MIT–BIH Arrhythmia Database, and compared our results with the scientific literature. The final results show that our model is not only more efficient than the state of the art in terms of accuracy, but also competitive in terms of sensitivity and specificity.
•We present a Deep Neural Network (DNN) for the heartbeat classification.•The DNN has been developed by using Tensor Flow and Google deep learning library.•The proposed DNN is composed of 7 hidden layers and has been built empirically.•Experiments have been carried out to test the proposed deep learning approach.•Numerical results have shown the effectiveness of the approach.
Background
We evaluated composite anterolateral thigh (ALT) flaps including vascularized fascia lata (FL), for stable soft tissue coverage and tendons restoration at various joint levels in a ...one‐stage procedure.
Methods
We performed a retrospective investigation including 21 “functional” ALT flaps between November 2006 and December 2016. In all patients included, FL was shaped to anatomical reproduce a tendon structure. Functional analysis included range of motion and force assessment. Functional scores were established according to Chen classification, DASH, and LEFS score. Defects resulted from tumor excision, trauma, burn, or infection‐debridement and were distributed in four main anatomical districts: knee (seven cases), ankle (six cases), forearm‐elbow (four cases), and hand‐wrist level (three cases).
Results
Nineteen flaps were raised as free flaps, while two as distally‐based propeller flaps. Average follow‐up was 38 months. Major complication requiring the harvest of a second flap was seen in two patients, whereas three flaps presented superficial necrosis and was treated in an outpatient regimen. We observed 81% of total ROM recovery compared to contralateral sides with 89% recovered articular stability. Best articulation outcomes were present in elbow reconstruction, while ankle reconstructions showed less articularity. Hospital stay was significantly reduced in hand and wrist functional reconstruction when compared with reconstruction at the ankle level (P < 0.05).
Conclusion
The ALT flap extended to vascularized FL provides a particularly effective and resistant tissue that can be folded to reconstruct and support tendinous structures. This can restore functional and structural integrity after complex defects in a single stage procedure.
•Our study compares the clinical usefulness of nerve ultrasound and nerve conduction study in patients with Bell’s palsy.•Nerve Ultrasound may show abnormally increased facial nerve diameter in the ...acute phase of Bell’s palsy.•The predictive value of facial nerve ultrasound for incomplete recovery is lower than that of the nerve conduction study.
This longitudinal study aims at assessing the predictive value of facial nerve high-resolution ultrasound (HRUS) for incomplete clinical recovery in patients with Bell’s palsy, the most common facial nerve disease.
We prospectively enrolled 34 consecutive patients with Bell’s palsy. All patients underwent neurophysiological testing (including facial nerve conduction study) and HRUS evaluations 10–15 days (T1), one month (T2), and three months (T3) after the onset of Bell’s palsy. Patients who did not experience complete recovery within three months were also evaluated after six months (T4). We have then compared the accuracy of HRUS with that of the facial nerve conduction study in predicting incomplete clinical recovery at three and six months.
At T1, the facial nerve diameter, as assessed with HRUS, was larger on the affected side than on the normal side, particularly in patients with incomplete recovery at T2, T3 and T4. ROC curve analysis, however, showed that the facial nerve diameter at T1 had a lower predictive value than the facial nerve conduction study for an incomplete clinical recovery at three (T3) and six (T4) months. Still, the facial nerve diameter asymmetry, as assessed with HRUS, had a relatively high negative predictive value (thus indicating a strong association between normal HRUS examination and a good prognosis).
Although HRUS shows abnormally increased facial nerve diameter in patients in the acute phase of Bell’s palsy, the predictive value of this technique for incomplete clinical recovery at three and six months is lower than that of the nerve conduction study.
Nerve ultrasound has a low predictive value for incomplete clinical recovery in patients with Bell’s Palsy.
•Nerve Ultrasound reveals enlarged nerves in Friedreich’s Ataxia.•Nerve abnormalities correlate with clinical disability scales.•Nerve ultrasound can provide useful information where nerve conduction ...study is no longer informative.
In Friedreich's ataxia research, the focus is on discovering treatments and biomarkers to assess disease severity and treatment effects. Our study examines high-resolution nerve ultrasound in these patients, seeking correlations with established clinical markers of disease severity.
Ten patients with Friedreich’s Ataxia underwent a comprehensive clinical assessment with established scales (SARA, FARS, mFARS, INCAT, ADL 0-36, IADL). Additionally, they underwent nerve conduction studies and high-resolution nerve ultrasound. Quantitative evaluation of nerve cross-sectional area, conducted at 24 nerve sites using high-resolution nerve ultrasound, was compared with data obtained from 20 healthy volunteers.
All the patients had a severe sensory axonal neuropathy. High-resolution nerve ultrasound showed significant increase, in cross sectional area, of median and ulnar nerves at the axilla and arm. The cumulative count of affected nerve sites was directly associated with clinical disability, as determined by SARA, FARS, mFARS, ADL 0-36, and INCAT score, while displaying an inverse correlation with IADL.
Our study shows that high-resolution ultrasound reveals notable nerve abnormalities, primarily in the upper limbs of patients diagnosed with Friedreich’s Ataxia. The observed correlation between these nerve abnormalities and clinical disability scales indicates the potential use of this technique as a biomarker for evaluating disease severity and treatment effects.
Nerve Ultrasound is a potential biomarker of disease severity in Friedreich’s Ataxia.
•A multi-scale beam model is derived by coupling CUF and ANM under the FE2 framework.•It benefits from both the efficiency of 1D CUF beam model and multi scale framework.•The introduction of CUF ...accelerates the resolution without compromising accuracy.
In this paper, a new paradigm for Carrera’s Unified Formulation (CUF) based on multiscale structural modelling is accomplished by bridging micromechanics and the advanced CUF one-dimensional/beam structural theories by means of the Multilevel Finite Element (also known as FE2) framework. Under the framework of the FE2 method, the analysis is divided into a macroscopic/structural problem and a microscopic/material problem. At the macroscopic level, several higher-order refined beam elements can be easily implemented via CUF by deriving a fundamental nucleus that is independent of the approximation order over the thickness and the number of nodes per element (they are free parameters of the formulation). The unknown macroscopic constitutive law is obtained by numerical homogenisation of a Representative Volume Element (RVE) at the microscopic level. Vice versa, the microscopic deformation gradient is calculated from the macroscopic model. Information is passed between the two scales in a FE2 sense. The resulting nonlinear problem is solved through the Asymptotic Numerical Method (ANM) that is more reliable and less Newton-Raphson’s one. The developed models are used as a first attempt to investigate the microstructure effect on the macrostructure geometrically nonlinear response. The proposed paradigm is used for investigating the effect of microscale imperfections (not straight carbon fibres) on the macroscale response (instability). Results are assessed in terms of accuracy and computational costs towards full FEM solutions. Three factors have been considered for an imperfection sensitivity parametric analysis: the defect wavelength as well as the amplitude and the size of RVE.
PDF
