Substitutional impurities in monolayer hexagonal boron nitride as single-photon emitters

Single-photon emitters in hexagonal boron nitride have attracted great attention over the last few years due to their excellent optoelectronical properties. Despite the vast range of results reported in the literature, studies on substitutional impurities belonging to the 13th and 15th groups have not been reported yet. Here, through theoretical modeling, we provide direct evidence that hexagonal boron nitride can be opportunely modified by introducing impurity atoms such as aluminum or phosphorus that may work as color centers for single-photon emission. By means of density functional theory, we focus on determining the structural stability, induced strain, and charge states of such defects and discuss their electronic properties. Nitrogen substitutions with heteroatoms of group 15 are shown to provide attractive features (e.g. deep defect levels and localized defect states) for single-photon emission. These results may open up new possibilities for employing innovative quantum emitters based on hexagonal boron nitride for emerging applications in nanophotonics and nanoscale sensing devices

Phage-displayed peptides targeting specific tissues and organs

AbstractPhage display is a powerful and widely used technique to find novel peptide ligands. A massive amount of peptide sequences have been identified for all kinds of materials, and peptides that..

First-principles calculations of exciton radiative lifetimes in monolayer graphitic carbon nitride nanosheets: implications for photocatalysis

In this work, we report on the exciton radiative lifetimes of graphitic carbon nitride monolayers in the triazine-based (gC3N4-t) and heptazine-based (gC3N4-h) forms, as obtained by means of ground-state plus excited-state ab initio calculations. By analyzing the exciton fine structure, we highlight the presence of dark states and show that the photogenerated electron–hole (e-h) pairs in gC3N4-h are remarkably long-lived, with an effective radiative lifetime of 260 ns. This fosters the employment of gC3N4-h in photocatalysis and makes it attractive for the emerging field of exciton devices. Although very long intrinsic radiative lifetimes are an important prerequisite for several applications, pristine carbon nitride nanosheets show very low quantum photoconversion efficiency, mainly due to the lack of an efficient e-h separation mechanism. We then focus on a vertical heterostructure made of gC3N4-t and gC3N4-h layers, which shows a type-II band alignment and looks promising for achieving net charge separation

Copy Skills and Writing Abilities in Children With and Without Specific Learning Disabilities

Copying a text quickly and accurately is important both in school and in daily life. However, this skill has never been systematically studied, either in children with typical development (TD) or in children with specific learning disabilities (SLD). The aim of this research was to study the features of a copy task and its relationship with other writing tasks. For this purpose, 674 children with TD and 65 children with SLD from Grades 6 through 8 were tested with a copy task and other writing assessment tasks, measuring three aspects of writing: handwriting speed, spelling, and expressive writing. Children with SLD performed worse on the copy task, both in terms of speed and accuracy, than children with TD. Copy speed was predicted by grade level and by all three major writing skills for children with TD but only by handwriting speed and spelling for children with SLD. Copy accuracy was predicted by gender and the three major writing skills for children with TD but only by spelling for children with SLD. These results suggest that children with SLD also have difficulty copying a text and benefit less than children with TD from their other writing skills

Left ventricular geometry and diastolic function in the hypertensive heart : impact of age

Background and aim. The impact of aging on the relationship between left ventricular (LV) mass/geometry and diastolic function as assessed by updated echocardiographic methods, such as tissue Doppler, is poorly defined. We investigated this issue in a cohort of hypertensive patients. Methods. A total of 660 hypertensives (mean age 65±13 years, 48% men) with preserved LV systolic function underwent a comprehensive echo-Doppler examination for routine clinical indications. For the present analysis, the subjects have been divided in two age groups (<65 or ≥65 years). Results. Overall, 61% of subjects fulfilled the criteria for LVH, 18% for left atrial (LA) enlargement and 11% for altered LV filling index. Concentric LV geometry was 1.4-fold higher in older hypertensives than in younger counterparts; also the prevalence of LA enlargement and altered LV filling was 2.0- and 1.9-fold higher in the former group, respectively. In older hypertensives, at variance from younger ones, neither LV mass nor relative wall thickness (RWT), a continuous index of LV geometry, were independently correlated to conventional as well as tissue Doppler LV diastolic indexes. Conclusions. Our findings suggest the relationship between cardiac hypertrophy and diastolic function in hypertensive subjects is affected by aging-associated factors unrelated to the amount of LV mass as assessed by standard echocardiography. © 2013 Scandinavian Foundation for Cardiovascular Research

Circulating γδ T cells in young/adult and old patients with cutaneous primary melanoma

BACKGROUND: In a previous study we demonstrated the existence of numerical and functional alterations of γδ T cells in healthy elderly. Recently, we analysed the involvement of γδ T lymphocytes in malignant melanoma, describing a lower frequency of circulating γδ T cells, an altered pattern of cytokine production, and an impaired in vitro expansion of these cells in primary cutaneous melanoma patients. METHODS: In this study we investigated the existence of numerical and functional alterations of circulating γδ T cells in young/adult and old melanoma patients, comparing the data obtained with age-matched healthy subjects. RESULTS: We demonstrated that the number of circulating γδ(+ )T cells was significantly and similarly reduced in young/adult and old melanoma patients and in old healthy subjects in comparison with young healthy donors. The decrease was due to a reduction of Vδ2 T cells whereas the number of Vδ1 T cells was not affected. A higher percentage of γδ(+ )T cells producing TNF-α was found in old healthy donors, whereas a reduced number of TNF-α-producing γδ(+ )T cells was present in melanoma patients independently by age. No significant difference was observed in IFN-γ production. After a 10-day in vitro culture, both the percentage and the expansion index of γδ T cells, and in particular of Vδ2 subset, were significantly and similarly reduced both in young/adult and old melanoma patients, and in healthy aged people, in comparison with young/adult healthy subjects. CONCLUSIONS: Our study demonstrates that the numerical and functional impairment of γδ T cells found in melanoma patients is not correlated with age and that it has characteristics very similar to the alterations of γδ T cells found in old healthy subjects. We suggest that a similar impairment of γδ T cell population may be related to the increased susceptibility to tumors present in the elderly as well as in the pathogenesis of malignant melanoma

Stability and Bandgap Engineering of In1-{xGaxSe} Monolayer

Bandgap engineering of semiconductor materials represents a crucial step for their employment in optoelectronics and photonics. It offers the opportunity to tailor their electronic and optical properties, increasing the degree of freedom in designing new devices and widening the range of their possible applications. Here, we report the bandgap engineering of a layered InSe monolayer, a superior electronic and optical material, by substituting In atoms with Ga atoms. We developed a theoretical understanding of [Formula: see text] stability and electronic properties in its whole compositional range ([Formula: see text]) through first-principles density functional theory calculations, the cluster expansion method, and kinetic Monte Carlo simulations. Our findings highlight the possibility of modulating the InGaSe bandgap by ≈0.41 eV and reveal that this compound is an excellent candidate to be employed in many optoelectronic and photonic devices

Professional development of in-training museum educators: an experience of curriculum improvement in time of a pandemic

[EN] The present paper aims to illustrate the reorganization of two post-graduate courses, “Museum Education. Theoretical aspects” and “Advanced Studies in Museum Education” promoted by CDM (Center for Museum Studies) - Dept. of Education at Roma Tre University, carried out during the Covid-19 pandemic, and to analyze the education strategies adopted in terms of museum professionals development to face the Covid-19 museum and universities 2020 Italian lockdown.The results emerging from the quantitative evaluation of the module “Museum and Social Networks”, taking into consideration the activities and digital tools proposed, show the efficacy of the courses reorganization, in terms of transverse and professional skills development in university students, critical thinking and collaboration in particular. Moreover, the data analysis give useful indications in term of university online lectures, laboratory activities and practices in e-learning mode, evaluation tools and methodologies aimed at solliciting professional development of in-training museum educators in university learning context.Poce, A.; Valente, M.; Re, MR.; Amenduni, F.; De Medio, C. (2021). Professional development of in-training museum educators: an experience of curriculum improvement in time of a pandemic. En 7th International Conference on Higher Education Advances (HEAd'21). Editorial Universitat Politècnica de València. 1377-1384. https://doi.org/10.4995/HEAd21.2021.12881OCS1377138