IMPACT OF GEOLOCATION DATA ON AUGMENTED REALITY USABILITY: A COMPARATIVE USER TEST

While the use of location-based augmented reality (AR) for education has demonstrated benefits on participants’ motivation, engagement, and on their physical activity, geolocation data inaccuracy causes augmented objects to jitter or drift, which is a factor in downgrading user experience. We developed a free and open source web AR application and conducted a comparative user test (n = 54) in order to assess the impact of geolocation data on usability, exploration, and focus. A control group explored biodiversity in nature using the system in combination with embedded GNSS data, and an experimental group used an external module for RTK data. During the test, eye tracking data, geolocated traces, and in-app user-triggered events were recorded. Participants answered usability questionnaires (SUS, UEQ, HARUS).We found that the geolocation data the RTK group was exposed to was less accurate in average than that of the control group. The RTK group reported lower usability scores on all scales, of which 5 out of 9 were significant, indicating that inaccurate data negatively predicts usability. The GNSS group walked more than the RTK group, indicating a partial effect on exploration. We found no significant effect on interaction time with the screen, indicating no specific relation between data accuracy and focus. While RTK data did not allow us to better the usability of location-based AR interfaces, results allow us to assess our system’s overall usability as excellent, and to define optimal operating conditions for future use with pupils

CHARACTERIZATION AND VALORIZATION OF MAIZE LANDRACES FROM VALLE D'AOSTA

During 1949-1950 in Italy begun a formal investigation to characterize maize (Zea mays L.) cultivation. In 1954, started a project for the sampling of all Italian maize landraces; this work ended with the collection of 562 different accessions collected in all regions with the exception of Valle d’Aosta, even if historical cultivation of maize in this Region is well documented. In Italy maize landraces have been extensively grown until the mid of the XX century when the cultivation of hybrid took place due to their significant agronomic performances. Despite that, being Valle d’Aosta a mountain region where intensive maize cultivation never started, it was possible to preserve the presence of some landraces. These local materials, which are still cultivated, mainly at domestic level, have high importance from a genetic and historical point of view. Recently, 5 maize landraces from Valle d’Aosta and 2 landraces from the adjacent Canavese (Piedmont) have been collected and subjected to historic, morphologic and genetic characterization. These landraces were named after the sampling location as it follows: Arnad, Arnad-Crest, Chatillon, Entrebin, Perloz, Bianco Canavese, and Rostrato Canavese. Firstly, on these 6 varieties the historic characterization has been carried out. Information and photographs have been searched in local archives and this was crucial to prove their long presence in all the sampling sites under study. From this historic reconstruction, the variety Entrebin resulted as the one that is better historically characterized. To study the variability and differentiation of landraces from Valle d’Aosta, the genetic characterization was performed by the means of 10 SSR markers tested on 20 samples from each landrace. This study highlighted a significant genetic variability among the landraces and, especially, a good level of differentiation between the accessions under investigation. This last result may be explained by the long reproductive isolation experienced by these materials. Complete morphological characterization is actually ongoing. Preliminary morphological observations revealed that these landraces have, generally, flint kernels with the exception of Bianco Canavese (dent) whose color is variable from white (Bianco Canavese) to dark red (Chatillon). Arnad landrace showed 8 kernel rows, probably being an Eight-rowed Flint while the others presented more rows, like many Derived Races. Interestingly, Perloz and Rostrato Canavese showed kernels with an apical beak which was more pronounced in the latter. This suggest that these two landraces belong to the “Rostrata” group, which is common in mountain areas. The present work confirms the importance of mountain areas in conserving biodiversity and increases the rich Italian maize germplasm with materials well adapted to marginal areas. Such new genetic variability may be used to breed new materials for a more resilient agriculture

Metallostar Assemblies Based on Dithiocarbamates for Use as MRI Contrast Agents

Two different octadentate gadolinium chelates based on DO3A and DOTAGA chelates (hydration number q = 1) have been used to prepare a series of bi-, tri-, and tetrametallic d–f mixed-metal complexes. The piperazine-based dithiocarbamate linker ensures that rotation of the gadolinium chelates is restricted, leading to enhanced relaxivity (r1) values, which increase with the overall mass and number of gadolinium units. The r1 value (at 10 MHz, 25 °C) per gadolinium unit rises from 5.0 mM–1 s–1 for the Gd-DO3A-NH2 monogadolinium chelate to 9.2 mM–1 s–1 in a trigadolinium complex with a ruthenium(III) core. Using a 1.5 T clinical scanner operating at 63.87 MHz (25 °C), an 86% increase in the relaxivity per gadolinium unit is observed for this multimetallic compound compared to clinically approved Dotarem. The gadolinium complexes based on the DOTAGA chelate also performed well at 63.87 MHz, with a relaxivity value of 9.5 mM–1 s–1 per gadolinium unit being observed for the trigadolinium d–f mixed-metal complex with a ruthenium(III) core. The versatility of dithiocarbamate coordination chemistry thus provides access to a wide range of d–f hybrids with potential for use as high-performance MRI contrast agents

Combined Magnetic Resonance Imaging and Photodynamic Therapy Using Polyfunctionalised Nanoparticles Bearing Robust Gadolinium Surface Units

A robust dithiocarbamate tether allows novel gadolinium units based on DOTAGA (q = 1) to be attached to the surface of gold nanoparticles (2.6 ‐ 4.1 nm diameter) along with functional units offering biocompatibility, targeting and photodynamic therapy. A dramatic increase in relaxivity (r1) per Gd unit from 5.01 mM−1 s−1 in unbound form to 31.68 mM−1 s−1 (10 MHz, 37 °C) is observed when immobilised on the surface due to restricted rotation and enhanced rigidity of the Gd complex on the nanoparticle surface. The single‐step synthetic route provides a straightforward and versatile way of preparing multifunctional gold nanoparticles, including examples with conjugated zinc‐tetraphenylporphyrin photosensitizers. The lack of toxicity of these materials (MTT assays) is transformed on irradiation of HeLa cells for 30 minutes (PDT), leading to 75% cell death. In addition to passive targeting, the inclusion of units capable of actively targeting overexpressed folate receptors illustrates the potential of these assemblies as targeted theranostic agents

Crucial neuroprotective roles of the metabolite BH4 in dopaminergic neurons

Dopa-responsive dystonia (DRD) and Parkinson’s disease (PD) are movement disorders caused by the dysfunction of nigrostriatal dopaminergic neurons. Identifying druggable pathways and biomarkers for guiding therapies is crucial due to the debilitating nature of these disorders. Recent genetic studies have identified variants of GTP cyclohydrolase-1 (GCH1), the rate-limiting enzyme in tetrahydrobiopterin (BH4) synthesis, as causative for these movement disorders. Here, we show that genetic and pharmacological inhibition of BH4 synthesis in mice and human midbrain-like organoids accurately recapitulates motor, behavioral and biochemical characteristics of these human diseases, with severity of the phenotype correlating with extent of BH4 deficiency. We also show that BH4 deficiency increases sensitivities to several PD-related stressors in mice and PD human cells, resulting in worse behavioral and physiological outcomes. Conversely, genetic and pharmacological augmentation of BH4 protects mice from genetically- and chemically induced PD-related stressors. Importantly, increasing BH4 levels also protects primary cells from PD-affected individuals and human midbrain-like organoids (hMLOs) from these stressors. Mechanistically, BH4 not only serves as an essential cofactor for dopamine synthesis, but also independently regulates tyrosine hydroxylase levels, protects against ferroptosis, scavenges mitochondrial ROS, maintains neuronal excitability and promotes mitochondrial ATP production, thereby enhancing mitochondrial fitness and cellular respiration in multiple preclinical PD animal models, human dopaminergic midbrain-like organoids and primary cells from PD-affected individuals. Our findings pinpoint the BH4 pathway as a key metabolic program at the intersection of multiple protective mechanisms for the health and function of midbrain dopaminergic neurons, identifying it as a potential therapeutic target for PD

A Low-Power Programmable Dynamic Frequency Divider

In this paper, a solution to realize a low-power programmable frequency divider using dynamic logic is proposed. By cascading compact dual-modulus divider slice with recursive feedback mechanisms, any dividing ratio is easily implemented. A 5-stages 0.18 mum CMOS implementation demonstrates a power consumption factor as low as 235 nW/MHz under 1.2 V supply for high dividing ratios

A MEMS-based 2.4-GHz sub-sampling RF front-end for advanced healthcare applications

This work presents a Bulk Acoustic Wave (BAW) resonator based 2.4-GHz front-end compliant to the Bluetooth LE standard and targeting advanced biomedical applications. A new transceiver architecture is proposed that combines BAW resonators and a sub-sampling architecture. It takes advantage of the high-Q of BAW resonators to perform channel filtering directly at RF. At the same time it also carries-out the critical anti-alias filtering required by the subsequent sub-sampling down-conversion mixer generating quadrature samples of the selected channel at baseband. The high-Q resonator is also used in the frequency synthesis to provide a low phase noise reference clock. The front-end has been designed and integrated in a 0.18-μm standard CMOS process and the principle is validated with simulations and measurement results. © 2011 IEEE

Amorphous Silicon p-i-n Diodes, deposited by the VHF-GD Process: New Experimental Results

a-Si:H i-layers were deposited at different substrate temperatures and plasma excitation frequencies, while the other deposition parameters were kept constant. These layers were characterised by measuring the intrinsic mechanical stress and the defect density. At deposition temperatures of 200 to 250°C low stress and a low defect density were obtained for excitation frequencies between 60 and 70 MHz. A second part shows the spectral response of thick p-i-n diodes for different reverse bias voltages. The data reveal a better collection efficiency for the case where generation of carriers is uniform throughout the i-layer, as compared to non-uniform generation, where carriers concentrate near the p-i interface.PV-LABIMT-NE Number: 20