This review is devoted to the description of recent experimental results concerning the nonlinear optical properties of semiconductor-doped glasses SDGs with particular emphasis on the regime in which the energy of the incident photon is smaller than the energy gap. A considerable theoretical and experimental effort has been devoted in the last 10years to the fundamental aspects of quantumconfined structures, which have properties somewhat intermediate between the bulk crystals and atoms or molecules. From this point of view, SDGs represent an easily available test system, and optical techniques have been a major diagnostic tool. Luminescence and absorption spectroscopy were extensively used to characterize the electronic states. The experiments aimed at the measurement of the real and imaginary parts of the third-order optical susceptibility of SDGs below the bandgap are described in some detail, and the results obtained with different techniques are compared. Besides the intrinsic fast nonlinearity due to bound electrons, SDGs may present a larger but much slower nonlinearity due to the free carriers generated by two-photon absorption. This implies that experiments have to be properly designed for separation of the two effects. In this article we stress the importance of a detailed structural characterization of the samples. Knowledge of the volume fraction occupied by the nanocrystals is necessary in order to derive from the experimental data the intrinsic nonlinearity and to compare it with the bulk nonlinearity. We discuss recent experiments in which the dependence of the intrinsic nonlinearity on the crystal size is derived by performing, on the samples, measurements of the real part and imaginary part of the nonlinear optical susceptibility and measurements of crystal size and volume fraction. Structural characterization is of interest also for a better understanding of the physical processes underlying the growth of crystallites in SDGs. The average size of nanocrystals can be tailored by controlling the temperature or time of the treatment. The major problem is the size dispersion of the crystallites, which is intrinsic to the diffusion process. At present, this is the major source of the undesired inhomogeneous broadening of the optical transition lines of the SDGs. Efforts are at present being made to fabricate materials, SDGs included, which embed nanocrystals with a reduced spread of sizes. The interest in the nonlinear optical properties is due not only to fundamental reasons but also to possible applications for optical devices. Generally speaking, resonant nonlinearities are much larger than non-resonant nonlinearities, but they are not necessarily the most interesting for applications because materials at resonance absorb the incident radiation and also present long response times. The studies below the bandgap seem to indicate that the values of the intrinsic nonlinearities of nanocrystals in the structures which are at present available are similar to those of the bulk. New and better controlled structures are now under development and have to be tested from the viewpoint of optical nonlinearities. In several situations SDGs cannot be modelled as an ensemble of freely standing nanocrystals, with the glass matrix playing the role of an inert support. Phenomena such as trapping and darkening, which are very probably connected with electronic states at the glasssemiconductor interface, may play a role in determining the optical response. They might give rise to an extrinsic optical nonlinearity which can be even larger than the intrinsic nonlinearity. The physical processes which are involved in these extrinsic nonlinearities are poorly understood and at present being investigated.

We report on the generation of ultrashort tunable pulses with a cavityless traveling-wave scheme consisting of a parametric superfluorescence seed source and a parametric amplifier. We show that the traveling-wave approach, with its advantages of simplicity and direct generation of tunable energetic single pulses, can be used in the femtosecond regime, and to this end we discuss the performances that were obtained with pump pulses of ≈1-ps and 200-fs duration at wavelengths of 0.53 and 0.6 μm, respectively. Of particular interest is the β-barium borate-based traveling-wave parametric generator (type-II phase matching), since it offers the possibility of generating nearly transform-limited pulses that are continuously tunable within a wide spectral range to as high as 3 μm in the IR. With a diffraction-limited pump at 0.53 μm. we obtained tunable pulses in a 1.2× diffraction-limited beam, which could be focused, with an f/20 optics lens, to an intensity of 10¹³ GW/cm². A temperature-tuned lithium triborate-based femtosecond parametric generator, with its smaller group-velocity dispersion and absence of walk-off, can operate at a pump energy of as low as 30 μJ in a 200-fs pulse.

Due to the exponential growth of the number of subjects affected by coronavirus disease 2019 (COVID-19), the entire Italian health care system had to respond promptly and in a very short time with the need of semi-intensive and intensive care units. Moreover, trained dedicated COVID-19 teams consisting of physicians were coming from different specialties (intensivists or pneumologists and infectiologists), while respiratory therapists and nurses have been recruited to work on and on without rest. However, due to still limited and evolving knowledge of COVID-19, there are few recommendations concerning the need in respiratory rehabilitation and physiotherapy interventions. The presentation of this paper is the result of a consensus promoted by the Italian societies of respiratory health care professionals who contacted pulmonologists directly involved in the treatment and rehabilitation of COVID-19. The aim was to formulate the more proper and common suggestions to be applied in different hospital settings in offering rehabilitative programs and physiotherapy workforce planning for COVID-19 patients. Two main areas of intervention were identified: organization and treatment, which are described in this paper to face the emergency.

Amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurodegenerative disease caused by the degeneration of motor neurons. The burden for ALS caregivers is quite high. There are still few studies that have investigated the emotional impact of ALS care. We conducted a cross-sectional study among 40 ALS caregivers, assessing general worries, burden of care, depression, anxiety, perception of social support, and patients' severity of disease. Caregiver burden, depression, and anxiety were positively related with each other, and all these variables had a negative relation with social support. Patient's loss of physical functions was positively related with caregiver burden, anxiety, and somatic expression of depression. Caregivers expressed worries for their own health conditions. Given these results, we consider the hypothesis of an emotional-somatic impact of ALS care. The implications and limitations are discussed.

Background: Almost half of the people with chronic obstructive pulmonary disease (COPD) do not adhere to the prescribed treatments and report anxiety and depression as comorbidities, resulting in higher rates of exacerbations, hospitalizations, and worse clinical outcomes. Objective: This systematic review provided a synthesis of studies about the relationships between anxiety, depression, and adherence in people affected by COPD. Methods: English language publications were searched in the PUBMED, SCOPUS, PsycInfo, Web of Science, PsycArticles, and Cochrane Library databases from December 2020 to March 2021, following PRISMA guidelines. The reference lists of eligible studies and other relevant systematic reviews were also searched. Data extraction and critical appraisal were undertaken by two reviewers working independently. The reference lists of eligible studies and other relevant systematic reviews were also searched. Data extraction and critical appraisal were undertaken by two reviewers working independently. Results: A total of 34 studies (23 quantitative and 2 qualitative studies, 9 reviews) were included. The relationship between depression and treatment adherence was significant and negative. Adherence to both rehabilitation, psychological, and antidepressant pharmacological treatments in depressed patients was linked to a decreased risk of hospitalization. Moreover, depressed patients compliant with an antidepressant were more likely to adherent to COPD maintenance inhalers. On the other hand, the associations between anxiety and adherence were poorly investigated and high heterogeneity characterized the studies, leading to a weak and variable relationship as well as too few interventions. Conclusion: The systematic review highlights the variability in estimates of the relationship between depression, anxiety, and treatment adherence in COPD. It could be explained by methodological differences across the included studies. This suggests that standardization is critical to improving the precision of the estimates. Recommendations for future research include attention to causal inferences, an exploration of mechanisms to explain the relationships between both anxiety and depression and adherence in COPD, and a comprehensive, systematic approach.