Numerical and Experimental Validation of Active Vibration Control Logic Performance of a Hybrid Noise Control-Based Brick

The limitations of active noise control (ANC) in coping with low frequencies and of passive noise control (PNC) in coping with middle-high frequencies are objects of research that present the potentialities of hybrid noise control (HBC). It aims at combining both of the behaviours by broadening the range of absorbed frequencies. Among the several application fields, the AEC (architecture, engineering, and construction) market can take advantage for those applications in which the noise conditions are caused by sound sources that tune in a broad frequencies range. In this frame, the paper describes the numerical and experimental validation of the active behaviour of an under-development project of a hybrid noise control-based acoustic bricks. The latter intends to embed the potentialities of active vibrational noise control (AVC) and passive destructive interference (PDI) in a unique design of an easy-to-mount, 3D-printed, customisable smart acoustic blocks. Active vibration control, the object of this paper, is provided by a 5-mm thick aluminium circular plate with an attached piezoelectric patch. The vibration of the latter, depending on a specific control law, defines the vibration of the plate itself achieving an abatement of the reflection coefficient. Through mathematical modelling and tests in an impedance tube, the results show that the control logic can reach an average abatement of the reflection coefficient of 82% in the frequency range 144-1007 Hz

EphA3 Expressed in the Chicken Tectum Stimulates Nasal Retinal Ganglion Cell Axon Growth and Is Required for Retinotectal Topographic Map Formation

BACKGROUND: Retinotopic projection onto the tectum/colliculus constitutes the most studied model of topographic mapping and Eph receptors and their ligands, the ephrins, are the best characterized molecular system involved in this process. Ephrin-As, expressed in an increasing rostro-caudal gradient in the tectum/colliculus, repel temporal retinal ganglion cell (RGC) axons from the caudal tectum and inhibit their branching posterior to their termination zones. However, there are conflicting data regarding the nature of the second force that guides nasal axons to invade and branch only in the caudal tectum/colliculus. The predominant model postulates that this second force is produced by a decreasing rostro-caudal gradient of EphA7 which repels nasal optic fibers and prevents their branching in the rostral tectum/colliculus. However, as optic fibers invade the tectum/colliculus growing throughout this gradient, this model cannot explain how the axons grow throughout this repellent molecule. METHODOLOGY/PRINCIPAL FINDINGS: By using chicken retinal cultures we showed that EphA3 ectodomain stimulates nasal RGC axon growth in a concentration dependent way. Moreover, we showed that nasal axons choose growing on EphA3-expressing cells and that EphA3 diminishes the density of interstitial filopodia in nasal RGC axons. Accordingly, in vivo EphA3 ectodomain misexpression directs nasal optic fibers toward the caudal tectum preventing their branching in the rostral tectum. CONCLUSIONS: We demonstrated in vitro and in vivo that EphA3 ectodomain (which is expressed in a decreasing rostro-caudal gradient in the tectum) is necessary for topographic mapping by stimulating the nasal axon growth toward the caudal tectum and inhibiting their branching in the rostral tectum. Furthermore, the ability of EphA3 of stimulating axon growth allows understanding how optic fibers invade the tectum growing throughout this molecular gradient. Therefore, opposing tectal gradients of repellent ephrin-As and of axon growth stimulating EphA3 complement each other to map optic fibers along the rostro-caudal tectal axis

Photopatterned antibodies for selective cell attachment

We present a phototriggerable system that allows for the spatiotemporal controlled attachment of selected cell types to a biomaterial using immobilized antibodies that specifically target individual cell phenotypes.o-Nitrobenzyl caged biotin was used to functionalize chitosan membranes and mediate site-specific coupling of streptavidin and biotinylated antibodies after light activation. The ability of this system to capture and immobilize specific cells on a surface was tested using endothelial-specific biotinylated antibodies and nonspecific ones as controls. Homogeneous patterned monolayers of human umbilical vein endothelial cells were obtained on CD31-functionalized surfaces. This is a simple and generic approach that is applicable to other ligands, materials, and cell types and shows the flexibility of caged ligands to trigger and control the interaction between cells and biomaterials.We thank Martina Knecht (MPIP) for help with the synthesis of caged biotin and Dr. Ron Unger and Prof. C. J. Kirkpatrick (University Clinic Mainz, RepairLab) for providing HUVECs. C.A.C. acknowledges funding support from the Portuguese Foundation for Science and Technology (FCT) (fellowship SFRH/BD/61390/2009) and from the International Max-Planck Research School in Mainz. The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. REGPOT-CT2012-316331-POLARIS

Effect of the first wave of COVID-19 on Poison Control Centre activities in 21 European countries : an EAPCCT initiative

Peer reviewe

OPTIMIZING NOISE ABSORPTION THROUGH HYBRID ACOUSTIC BRICKS: NUMERICAL SENSITIVITY ANALYSIS OF THE ACTIVE VIBRATION CONTROL LOGIC

Hybrid acoustic absorber have been implemented in order to overcome the limitations of common acoustic panel used for the control of room acoustics parameters. Indeed, the hybrid system allows to enhance the acoustic absorption in a wider frequency range. In this research frame, a hybrid absorber block has been developed by combining active Structural Acoustic Control (ASAC) and high frequencies Passive Noise Control (PNC). This innovative smart structure, made of 3D-printed blocks, offers an easy-to- mount and customizable solution. It has potential applications in many fields, such as architecture, engineering and construction industry, where noise is generated by broadband sound sources. The passive destructive interference proved to be an effective solution for high frequencies, where the wavelengths of interest are quite small, but it is difficult to be implemented at low frequencies and where space is limited. This paper focuses on the sensitivity analysis of the parameters of the active contribution. It is here implemented through a 5mm thick aluminum plate actuated by a piezoelectric patch. Mathematical modeling and tests with the Kundt tube demonstrate that the proposed approach can increase the average absorption coefficient in normal incidence condition by more than 80%, in the 125-1000 Hz frequency range

TGF-β controls MIR-181/ERK regulatory network during retinal axon specification and growth

Retinal axon specification and growth are critically sensitive to the dosage of numerous signaling molecules and transcription factors. Subtle variations in the expression levels of key molecules may result in a variety of axonal growth anomalies. miR-181a and miR-181b are two eye-enriched microRNAs whose inactivation in medaka fish leads to alterations of the proper establishment of connectivity and function in the visual system. miR-181a/b are fundamental regulators of MAPK signaling and their role in retinal axon growth and specification is just beginning to be elucidated. Here we demonstrate that miR-181a/b are key nodes in the interplay between TGF-β and MAPK/ERK within the functional pathways that control retinal axon specification and growth. Using a variety of in vivo and in vitro approaches in medaka fish, we demonstrate that TGF-β signaling controls the miR-181/ERK regulatory network, which in turn strengthens the TGF-β-mediated regulation of RhoA degradation. Significantly, these data uncover the role of TGF-β signaling in vivo, for the first time, in defining the correct wiring and assembly of functional retina neural circuits and further highlight miR-181a/b as key factors in axon specification and growth

Biological risk among agriculture and construction workers in Molise Region, Central Italy

Background: Biological risk is a significant issue in workplaces due to continuous modification of work organization and condition. Objectives: In this pilot study, perception and knowledge of biological risk, as well as adoption of prevention measures were evaluated among construction and agriculture workers. Methods: A structured questionnaire was administered to workers to collect socio-demographic and employment information, in addition to data on risk perception and knowledge, and adoption of preventive measures, including those related to work activities. Results: Fifty-three workers aged 45.3 +/- 9.8 years participated in the study, 81% were male, and 70% were construction workers. Approximately 80% of participants declared that infectious diseases are neither frequent nor health-threatening in their occupational activity. The majority of workers considered some diseases, such as hepatitis A and B, leptospirosis and listeriosis, as posing a low risk to their health. Forty-seven % claimed to be unexposed to biohazards at their workplace, and 72% were not worried about them. Ninety-six % of the workers knew about vaccination for tetanus, but only 74% and 36% knew about the availability of vaccination for Hepatitis A and B, respectively. During lifetime, 94% of the workers received at least one vaccination. All workers had undergone tetanus vaccination, but only few received vaccine for influenza, hepatitis B and tuberculosis. Conclusions: This pilot study in occupational settings revealed a poor perception of biological risk and a limited awareness of the severity of infectious diseases. Major knowledge gaps existed about the available preventive measures. It is essential to promote safety culture at the workplace also with regard to biological hazards. This requires improving information and education, conducting appropriate studies, and prompting health and safety professional actors to focus on occupational infectious disease problems