Direct bandgap quantum wells in hexagonal Silicon Germanium.

Silicon is indisputably the most advanced material for scalable electronics, but it is a poor choice as a light source for photonic applications, due to its indirect band gap. The recently developed hexagonal Si1-xGex semiconductor features a direct bandgap at least for x > 0.65, and the realization of quantum heterostructures would unlock new opportunities for advanced optoelectronic devices based on the SiGe system. Here, we demonstrate the synthesis and characterization of direct bandgap quantum wells realized in the hexagonal Si1-xGex system. Photoluminescence experiments on hex-Ge/Si0.2Ge0.8 quantum wells demonstrate quantum confinement in the hex-Ge segment with type-I band alignment, showing light emission up to room temperature. Moreover, the tuning range of the quantum well emission energy can be extended using hexagonal Si1-xGex/Si1-yGey quantum wells with additional Si in the well. These experimental findings are supported with ab initio bandstructure calculations. A direct bandgap with type-I band alignment is pivotal for the development of novel low-dimensional light emitting devices based on hexagonal Si1-xGex alloys, which have been out of reach for this material system until now.

Low Surface Recombination in Hexagonal SiGe Alloy Nanowires: Implications for SiGe-Based Nanolasers.

Monolithic integration of silicon-based electronics and photonics could open the door toward many opportunities including on-chip optical data communication and large-scale application of light-based sensing devices in healthcare and automotive; by some, it is considered the Holy Grail of silicon photonics. The monolithic integration is, however, severely hampered by the inability of Si to efficiently emit light. Recently, important progress has been made by the demonstration of efficient light emission from direct-bandgap hexagonal SiGe (hex-SiGe) alloy nanowires. For this promising material, realized by employing a nanowire structure, many challenges and open questions remain before a large-scale application can be realized. Considering that for other direct-bandgap materials like GaAs, surface recombination can be a true bottleneck, one of the open questions is the importance of surface recombination for the photoluminescence efficiency of this new material. In this work, temperature-dependent photoluminescence measurements were performed on both hex-Ge and hex-SiGe nanowires with and without surface passivation schemes that have been well documented and proven effective on cubic silicon and germanium to elucidate whether and to what extent the internal quantum efficiency (IQE) of the wires can be improved. Additionally, time-resolved photoluminescence (TRPL) measurements were performed on unpassivated hex-SiGe nanowires as a function of their diameter. The dependence of the surface recombination on the SiGe composition could, however, not be yet addressed given the sample-to-sample variations of the state-of-the-art hex-SiGe nanowires. With the aforementioned experiments, we demonstrate that at room temperature, under high excitation conditions (a few kW cm-2), the hex-(Si)Ge surface is most likely not a bottleneck for efficient radiative emission under relatively high excitation conditions. This is an important asset for future hex(Si)Ge optoelectronic devices, specifically for nanolasers.

Digital Health Service for Identification of Frailty Risk Factors in Community-Dwelling Older Adults: The SUNFRAIL+ Study Protocol.

This article reports the study protocol of a nationwide multicentric study in seven Italian regions aimed at assessing the effectiveness of a digitally supported approach for the early screening of frailty risk factors in community-dwelling older adults. SUNFRAIL+ is a prospective observational cohort study aimed at carrying out a multidimensional assessment of community-dwelling older adults through an IT platform, which allows to connect the items of the SUNFRAIL frailty assessment tool with a cascading multidimensional in-depth assessment of the bio-psycho-social domains of frailty. Seven centers in seven Italian regions will administer the SUNFRAIL questionnaire to 100 older adults. According to the answers provided by older adults, they will be subjected to one or more validated in-depth scale tests in order to perform further diagnostic or dimensional evaluations. The study aims to contribute to the implementation and validation of a multiprofessional and multistakeholder service model for the screening of frailty in community-dwelling older adult population.

The Impact of COVID-19 Pandemic on Psychiatric Emergencies in Two Different Settings: Emergency Room and Community Mental Health Service.

Background: The SARS-CoV-2 pandemic caused a public health emergency with profound consequences on physical and mental health of individuals. Emergency Rooms (ER) and Community Mental Health Services (CMHS) played a key role in the management of psychiatric emergencies during the pandemic. The purpose of the study was to evaluate urgent psychiatric consultations (UPCs) in the ERs of the General Hospitals and in the CMHS of a Northern Italian town during the pandemic period. Methods: This monocentric observational study collected UPCs carried out in ER from 01/03/2020 to 28/02/2021 (the so called "COVID-19 period") and the demographic and clinical characteristics of patients who required UPCs in the 12-months period, comparing these data with those collected from 01/03/2019 to 29/02/2020 (the so called "pre-COVID-19 period"). The same variables were collected for UPCs carried out in CMHS from 01/03/2020 to 31/01/2021 and compared with those collected from 01/03/2019 to 31/01/2020. The data, were statistically analyzed through STATA 12-2011. Results: In ER, we reported a 24% reduction in UPCs during the COVID-19 period (n = 909) in comparison with the pre-COVID-19 period (n = 1,194). Differently, we observed an increase of 4% in UPCs carried out in CMHS during the COVID-19 period (n = 1,214) in comparison with the previous period (n = 1,162). We observed an increase of UPCs in ER required by people who lived in psychiatric facilities or with disability pension whereas more UPCs in CMHS were required by older people or those living in other institutions compared to the previous period. In the COVID-19 period, the most frequent reasons for UPCs in ER were aggressiveness, socio-environmental maladjustment and psychiatric symptoms in organic disorders whereas in CMHS we reported an increase of UPCs for control of psychopharmacology therapy and mixed state/mania. Conclusion: In light of our findings, we conclude that the most vulnerable people required more frequent attention and care in both ER and CMHS during pandemic, which disrupted individuals' ability to adapt and induced many stressful reactive symptoms. In order to reduce the impact of the COVID-19 pandemic on mental health, psychological support interventions for the general population should be implemented, having particular regard for more psychologically fragile people.

Psychiatric Emergencies During the Covid-19 Pandemic: A 6-Month Observational Study.

BACKGROUND: The new SARS-CoV-2 has caused an ongoing pandemic. Health prevention measures to contain the outbreak are profoundly affecting the physical and mental health as well as personal freedom of the population. AIM: To evaluate psychiatric emergencies in a 6-month period during the COVID-19 pandemic in 2020 compared to those of the corresponding period of the previous year. METHODS: This monocentric observational study preliminarily collected variables of the urgent psychiatric consultations (UPCs) carried out in emergency room (ER) from 1-3-2020 to 31-8-2020 and the socio-demographic and clinical characteristics of patients who required UPCs in the 6-month period, comparing these data with those collected from 1-3-2019 to 31-8-2019. The data, collected in alpha-numeric code, were statistically analyzed through STATA 12-2011. RESULTS: This research reported a reduction of both UPCs and hospital psychiatric admissions. Concomitantly, we observed an increase of UPCs required by people already being treated by psychiatric and other health services, residents in psychiatric facilities and non-Italians. In 2020, differently from 2019, the most frequent reasons for urgent psychiatric consultations were aggressive behavior and adjustment disorders with anxiety and depressive mood. CONCLUSION: This preliminary study suggests that, during the COVID-19 epidemic, urgent psychiatric consultations in ER were reduced, except for the most vulnerable people due to their clinical and/or social conditions.

"Shedding Light on Light": A Review on the Effects on Mental Health of Exposure to Optical Radiation.

In relation to human health and functioning, light, or more specifically optical radiation, plays many roles, beyond allowing vision. These may be summarized as: regulation of circadian rhythms; consequences of direct exposure to the skin; and more indirect effects on well-being and functioning, also related to lifestyle and contact with natural and urban environments. Impact on mental health is relevant for any of these specifications and supports a clinical use of this knowledge for the treatment of psychiatric conditions, such as depression or anxiety, somatic symptom disorder, and others, with reference to light therapy in particular. The scope of this narrative review is to provide a summary of recent findings and evidence on the regulating functions of light on human beings' biology, with a specific focus on mental health, its prevention and care.