What regulates the velocity distribution of interstellar clouds?

Kinetic energy stored in ISM bulk/turbulent motions is a crucial ingredient to properly describe most properties of observed galaxies. By using Monte Carlo simulations, we investigate how this energy is injected by supernovae and dissipated via cloud collisions and derive the corresponding ISM velocity probability distribution function (PDF). The functional form of the PDF for the modulus of the velocity dispersion is $$p(v) \propto v^2 \exp[-(v/\sigma)^\beta].$$ The power-law index of the PDF depends only on the value of the average cloud collision elasticity as \beta = 2\exp( -1). If \beta and the gas velocity dispersion \sigma are known, the specific kinetic energy dissipated by collisions is found to be \propto \sigma^2 \ln (2 / \beta)/(\beta-0.947); in steady state, this is equal to the energy input from SNe. We predict that in a multiphase, low metallicity (Z \approx 5 \times 10^{-3} Z_\odot) ISM the PDF should be close to a Maxwellian (\beta = 2) with velocity dispersion \sigma \simgt 11$ km s\m; in more metal rich systems (Z \simgt 5 \times 10^{-2} Z_\odot), instead, we expect to observe almost exponential PDFs. This is in good agreement with a number of observations that we review and might explain the different star formation modes seen in dwarfs and spiral galaxies.Comment: Accepted for publication of MNRAS. 10 pages including 7 figure

Piezoelectric Nanomaterials Activated by Ultrasound: The Pathway from Discovery to Future Clinical Adoption

Electrical stimulation has shown great promise in biomedical applications, such as regenerative medicine, neuromodulation, and cancer treatment. Yet, the use of electrical end effectors such as electrodes requires connectors and batteries, which dramatically hamper the translation of electrical stimulation technologies in several scenarios. Piezoelectric nanomaterials can overcome the limitations of current electrical stimulation procedures as they can be wirelessly activated by external energy sources such as ultrasound. Wireless electrical stimulation mediated by piezoelectric nanoarchitectures constitutes an innovative paradigm enabling the induction of electrical cues within the body in a localized, wireless, and minimally invasive fashion. In this review, we highlight the fundamental mechanisms of acoustically mediated piezoelectric stimulation and its applications in the biomedical area. Yet, the adoption of this technology in a clinical practice is in its infancy, as several open issues, such as piezoelectric properties measurement, control of the ultrasound dose in vitro, modeling and measurement of the piezo effects, knowledge on the triggered bioeffects, therapy targeting, biocompatibility studies, and control of the ultrasound dose delivered in vivo, must be addressed. This article explores the current open challenges in piezoelectric stimulation and proposes strategies that may guide future research efforts in this field toward the translation of this technology to the clinical scene

Optimal low-intensity pulsed ultrasound stimulation for promoting anti-inflammatory effects in macrophages

: In this paper, we stimulated M1-like macrophages (obtained from U937 cells) with low-intensity pulsed ultrasound (LIPUS) to lower pro-inflammatory cytokine production. A systematic screening of different frequencies, intensities, duty cycles, and exposure times was performed. The optimal stimulation conditions leading to a marked decrease in the release of inflammatory cytokines were determined to be 38 kHz, 250 mW/cm2, 20%, and 90 min, respectively. Using these parameters, we verified that up to 72 h LIPUS did not affect cell viability, resulting in an increase in metabolic activity and in a reduction of reactive oxygen species (ROS) production. Moreover, we found that two mechanosensitive ion channels (PIEZO1 and TRPV1) were involved in the LIPUS-mediated cytokine release modulation. We also assessed the role of the nuclear factor κB (NF-κB) signaling pathway and observed an enhancement of actin polymerization. Finally, transcriptomic data suggested that the bioeffects of LIPUS treatment occur through the modulation of p38 MAPK signaling pathway

Energy Dissipation in Interstellar Cloud Collisions

We present a study of the kinetic energy dissipation in interstellar cloud collisions. The main aim is to understand the dependence of the elasticity (defined as the ratio of the final to the initial kinetic energy of the clouds) on the velocity and mass ratio of the colliding clouds, magnetic field strength, and gas metallicity for head-on collisions. The problem has been studied both analytically and via numerical simulations. We have derived handy analytical relationships that well approximate the analogous numerical results. The main findings of this work are: (i) the kinetic energy dissipation in cloud collisions is minimum (i.e. the collision elasticity is maximum) for a cloud relative velocity $v_r \simeq 30 km s^{-1}$; (ii) the above minimum value is proportional $Z L_c^2$, where $Z$ is the metallicity and $L_c$ is the cloud size: the larger is $Z L_c^2$ the more dissipative (i.e. inelastic) the collision will be; (iii) in general, we find that the energy dissipation decreases when the magnetic field strength, and mass ratio of the clouds are increased and the metallicity is decreased, respectively. We briefly discuss the relevance of this study to the global structure of the interstellar medium and to galaxy formation and evolution.Comment: 16 pages, aasms LaTeX, 7 figures. ApJ, accepte

Suicide spectrum among young people during the COVID-19 pandemic: A systematic review and meta-analysis

BACKGROUND: There are concerns that suicidal behaviors are arising among adolescents. The COVID-19 pandemic could have worsened the picture, however, studies on this topic reported contrasting results. This work aimed to summarise findings from the worldwide emerging literature on the rates of suicidality among young people during the COVID-19 pandemic. METHODS: A systematic review and meta-analysis were performed, searching five electronic databases for studies published from January 1, 2020 until July 27, 2022. Studies reporting rates for each of the three considered outcomes (suicide, suicidal behaviors, and suicidal ideation) among young people under 19 years old during the COVID-19 pandemic were included. Random-effects meta-analyses were conducted, and the intra-study risk of bias was assessed. When pre-COVID-19 data were available, incidence rate ratio (IRR) and prevalence ratio (PR) estimates were calculated between the two periods. All the analyses were performed according to the setting explored: general population, emergency department (ED), and psychiatric services. The review protocol was registered on PROSPERO (CRD42022308014). FINDINGS: Forty-seven observational studies were selected for more than 65 million subjects. The results of the meta-analysis showed a pooled annual incidence rate of suicides of 4.9 cases/100,000 during 2020, accounting for a non-statistically significant increase of 10% compared to 2019 (IRR 1.10, 95% CI: 0.94–1.29). The suicidal behaviors pooled prevalence during the COVID-19 pandemic was higher in the psychiatric setting (25%; 95% CI: 17–36%) than in the general population (3%; 1–13%) and ED (1%; 0–9%). The pooled rate of suicidal ideation was 17% in the general population (11–25%), 36% in psychiatric setting (20–56%) and 2% in ED (0–12%). The heterogeneity level was over 97% for both outcomes in all settings considered. The comparison between before and during COVID-19 periods highlighted a non-statistically significant upward trend in suicidal behaviors among the general population and in ED setting. The only significant increase was found for suicidal ideation in psychiatric setting among studies conducted in 2021 (PR 1.15; 95% CI: 1.04–1.27), not observed exploring 2020 alone. INTERPRETATION: During the pandemic, suicide spectrum issues seemed to follow the known pattern described in previous studies, with higher rates of suicidal ideation than of suicidal behaviors and suicide events. Governments and other stakeholders should be mindful that youth may have unique risks at the outset of large disasters like the COVID-19 pandemic and proactive steps are necessary to address the needs of youth to mitigate those risks. FUNDING: The present study was funded by the 10.13039/501100006692University of Torino (CHAL_RILO_21_01)

Population III stars: hidden or disappeared ?

A PopIII/Pop II transition from massive to normal stars is predicted to occur when the metallicity of the star forming gas crosses the critical range Z_cr = 10^(-5 +/- 1) Z_sun. To investigate the cosmic implications of such process we use numerical simulations which follow the evolution, metal enrichment and energy deposition of both Pop III and Pop II stars. We find that: (i) due to inefficient heavy element transport by outflows and slow "genetic" transmission during hierarchical growth, large fluctuations around the average metallicity arise; as a result Pop III star formation continues down to z=2.5, but at a low peak rate of 10^-5 M_sun yr^-1 Mpc^-3 occurring at z~6 (about 10^-4 of the PopII one); (ii) Pop III star formation proceeds in a "inside-out" mode in which formation sites are progressively confined at the periphery of collapsed structures, where the low gas density and correspondingly long free-fall timescales result in a very inefficient astration. These conclusions strongly encourage deep searches for pristine star formation sites at moderate (2<z<5) redshifts where metal free stars are likely to be hidden.Comment: to appear in MNRA

Key performance indicators for monitoring the integrated care pathway in breast cancer: the E.Pic.A. project

Introduction: Due to its high incidence, evaluating performance of care delivered to breast cancer patients is a crucial issue. The multidisciplinary panel E.Pic.A. (Economic Appropriateness of an Integrated Care Pathway) defined a set of key performance indexes (KPIs) to evaluate economic waste in breast cancer healthcare interventions. Methods: The E.Pic.A. panel identified the principal KPIs that are crucial within the breast cancer care pathway to evaluate the performance of care. KPIs were defined taking into account their reliability, validity, usability and feasibility of measurement through the linkage between multiple routine healthcare data sources. Results: 7 KPIs were identified: 3 on instrumental diagnostics, 2 on surgery and 2 on treatment. The 3 KPIs regarding instrumental diagnostics are aimed at assessing the inappropriateness of diagnostic tests performed before and after the index surgery. The 2 KPIs regarding surgery measure the inappropriateness of possible repeated interventions considering the time elapsed from the index surgery. The 2 KPIs regarding oncologic therapy measure the inappropriateness about the administration time of adjuvant therapy and radiotherapy considering the time elapsed from the index surgery. Conclusion: E.Pic.A methodology could help to evaluate economic waste in healthcare interventions with the objective of redirecting resources to interventions with greater value

Super-telomeres in transformed human fibroblasts

Telomere length maintenance is critical for organisms' long-term survival and cancer cell proliferation. Telomeres are kept within species-specific length ranges by the interplay between telomerase activity and telomeric chromatin organization. In this paper, we exploited telomerase immortalized human fibroblasts (cen3tel) that gradually underwent neoplastic transformation during culture propagation to study telomere composition and length regulation during the transformation process. Just after telomerase catalytic subunit (hTERT) expression, cen3tel telomeres shortened despite the presence of telomerase activity. At a later stage and concomitantly with transformation, cells started elongating telomeres, which reached a mean length greater than 100kb in about 900 population doublings. Super-telomeres were stable and compatible with cell growth and tumorigenesis. Telomere extension was associated with increasing levels of telomerase activity that were linked to the deregulation of endogenous telomerase RNA (hTERC) and exogenous telomerase reverse transcriptase (hTERT) expression. Notably, the increase in hTERC levels paralleled the increase in telomerase activity, suggesting that this subunit plays a role in regulating enzyme activity. Telomeres ranging in length between 10 and more than 100kb were maintained in an extendible state although TRF1 and TRF2 binding increased with telomere length. Super-telomeres neither influenced subtelomeric region global methylation nor the expression of the subtelomeric gene FRG1, attesting the lack of a clear-cut relationship between telomere length, subtelomeric DNA methylation and expression in human cells. The cellular levels of the telomeric proteins hTERT, TRF1, TRF2 and Hsp90 rose with transformation and were independent of telomere length, pointing to a role of these proteins in tumorigenesis

Ultra faint dwarfs: probing early cosmic star formation

We investigate the nature of the newly discovered Ultra Faint dwarf spheroidal galaxies (UF dSphs) in a general cosmological context simultaneously accounting for various ``classical`` dSphs and Milky Way properties including their Metallicity Distribution Function (MDF). To this aim we extend the merger tree approach previously developed to include the presence of star-forming minihaloes, and an heuristic prescription for radiative feedback. The model successfully reproduces both the observed [Fe/H]-Luminosity relation and the mean MDF of UFs. In this picture UFs are the oldest, most dark matter-dominated (M/L > 100) dSphs with a total mass M= 10^{7-8}Msun; they are leftovers of H_2-cooling minihaloes formed at z > 8.5, i.e. before reionization. Their MDF is broader (because of a more prolonged SF) and shifted towards lower [Fe/H] (as a result of a lower gas metallicity at the time of formation) than that of classical dSphs. These systems are very ineffectively star-forming, turning into stars by z=0 only <3% of the potentially available baryons. We provide a useful fit for the star formation efficiency of dSphs.Comment: 5 pages, 4 figures, accepted for publication in MNRAS http://saveitalianbrains.wordpress.co