Mental health concerns during the COVID-19 pandemic as revealed by helpline calls.

Mental health is an important component of public health, especially in times of crisis. However, monitoring public mental health is difficult because data are often patchy and low-frequency1-3. Here we complement established approaches by using data from helplines, which offer a real-time measure of 'revealed' distress and mental health concerns across a range of topics4-9. We collected data on 8 million calls from 19 countries, focusing on the COVID-19 crisis. Call volumes peaked six weeks after the initial outbreak, at 35% above pre-pandemic levels. The increase was driven mainly by fear (including fear of infection), loneliness and, later in the pandemic, concerns about physical health. Relationship issues, economic problems, violence and suicidal ideation, however, were less prevalent than before the pandemic. This pattern was apparent both during the first wave and during subsequent COVID-19 waves. Issues linked directly to the pandemic therefore seem to have replaced rather than exacerbated underlying anxieties. Conditional on infection rates, suicide-related calls increased when containment policies became more stringent and decreased when income support was extended. This implies that financial relief can allay the distress triggered by lockdown measures and illustrates the insights that can be gleaned from the statistical analysis of helpline data.

Deep strong light-matter coupling in plasmonic nanoparticle crystals.

In the regime of deep strong light-matter coupling, the coupling strength exceeds the transition energies of the material1-3, fundamentally changing its properties4,5; for example, the ground state of the system contains virtual photons and the internal electromagnetic field gets redistributed by photon self-interaction1,6. So far, no electronic excitation of a material has shown such strong coupling to free-space photons. Here we show that three-dimensional crystals of plasmonic nanoparticles can realize deep strong coupling under ambient conditions, if the particles are ten times larger than the interparticle gaps. The experimental Rabi frequencies (1.9 to 3.3 electronvolts) of face-centred cubic crystals of gold nanoparticles with diameters between 25 and 60 nanometres exceed their plasmon energy by up to 180 per cent. We show that the continuum of photons and plasmons hybridizes into polaritons that violate the rotating-wave approximation. The coupling leads to a breakdown of the Purcell effect-the increase of radiative damping through light-matter coupling-and increases the radiative polariton lifetime. The results indicate that metallic and semiconducting nanoparticles can be used as building blocks for an entire class of materials with extreme light-matter interaction, which will find application in nonlinear optics, the search for cooperative effects and ground states, polariton chemistry and quantum technology4,5.

Dielectric Screening inside Carbon Nanotubes.

Dielectric screening plays a vital role in determining physical properties at the nanoscale and affects our ability to detect and characterize nanomaterials using optical techniques. We study how dielectric screening changes electromagnetic fields and many-body effects in nanostructures encapsulated inside carbon nanotubes. First, we show that metallic outer walls reduce the scattering intensity of the inner tube by 2 orders of magnitude compared to that of air-suspended inner tubes, in line with our local field calculations. Second, we find that the dielectric shift of the optical transition energies in the inner walls is greater when the outer tube is metallic than when it is semiconducting. The magnitude of the shift suggests that the excitons in small-diameter inner metallic tubes are thermally dissociated at room temperature if the outer tube is also metallic, and in essence, we observe band-to-band transitions in thin metallic double-walled nanotubes.

The Effect of Digital Mental Health Literacy Interventions on Mental Health: Systematic Review and Meta-Analysis.

BACKGROUND: Accelerated by technological advancements and the recent global pandemic, there is burgeoning interest in digital mental health literacy (DMHL) interventions that can positively affect mental health. However, existing work remains inconclusive regarding the effectiveness of DMHL interventions. OBJECTIVE: This systematic review and meta-analysis investigated the components and modes of DMHL interventions, their moderating factors, and their long-term impacts on mental health literacy and mental health. METHODS: We used a random-effects model to conduct meta-analyses and meta-regressions on moderating effects of DMHL interventions on mental health. RESULTS: Using 144 interventions with 206 effect sizes, we found a moderate effect of DMHL interventions in enhancing distal mental health outcomes (standardized mean difference=0.42, 95% CI -0.10 to 0.73; P<.001) and a large effect in increasing proximal mental health literacy outcomes (standardized mean difference=0.65, 95% CI 0.59-0.74; P<.001). Uptake of DMHL interventions was comparable with that of control conditions, and uptake of DMHL interventions did not moderate the effects on both proximal mental health literacy outcomes and distal mental health outcomes. DMHL interventions were as effective as face-to-face interventions and did not differ by platform type or dosage. DMHL plus interventions (DMHL psychoeducation coupled with other active treatment) produced large effects in bolstering mental health, were more effective than DMHL only interventions (self-help DMHL psychoeducation), and were comparable with non-DMHL interventions (treatment as usual). DMHL interventions demonstrated positive effects on mental health that were sustained over follow-up assessments and were most effective in enhancing the mental health of emerging and older adults. CONCLUSIONS: For theory building, our review and meta-analysis found that DMHL interventions are as effective as face-to-face interventions. DMHL interventions confer optimal effects on mental health when DMHL psychoeducation is combined with informal, nonprofessional active treatment components such as skills training and peer support, which demonstrate comparable effectiveness with that of treatment as usual (client-professional interactions and therapies). These effects, which did not differ by platform type or dosage, were sustained over time. Additionally, most DMHL interventions are found in Western cultural contexts, especially in high-income countries (Global North) such as Australia, the United States, and the United Kingdom, and limited research is conducted in low-income countries in Asia and in South American and African countries. Most of the DMHL studies did not report information on the racial or ethnic makeup of the samples. Future work on DMHL interventions that target racial or ethnic minority groups, particularly the design, adoption, and evaluation of the effects of culturally adaptive DMHL interventions on uptake and mental health functioning, is needed. Such evidence can drive the adoption and implementation of DMHL interventions at scale, which represents a key foundation for practice-changing impact in the provision of mental health resources for individuals and the community. TRIAL REGISTRATION: PROSPERO International Prospective Register of Systematic Reviews CRD42023363995; https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023363995.

Radial Alignment of Carbon Nanotubes via Dead-End Filtration.

Dead-end filtration is a facile method to globally align single wall carbon nanotubes (SWCNTs) in large area films with a 2D order parameter, S2D , approaching unity. Uniaxial alignment has been achieved using pristine and hot-embossed membranes but more sophisticated geometries have yet to be investigated. In this work, three different patterns with radial symmetry and an area of 3.8 cm2 are created. Two of these patterns are replicated by the filtered SWCNTs and S2D values of ≈0.85 are obtained. Each of the radially aligned SWCNT films is characterized by scanning cross-polarized microscopy in reflectance and laser imaging in transmittance with linear, radial, and azimuthal polarized light fields. The former is used to define a novel indicator akin to the 2D order parameter using Malu's law, yielding 0.82 for the respective film. The films are then transferred to a flexible printed circuit board and terminal two-probe electrical measurements are conducted to explore the potential of those new alignment geometries.

Synthesis of two-dimensional triazine covalent organic frameworks at ambient conditions to detect and remove water pollutants.

Synthesis of fully triazine frameworks (C3N3) by metal catalyzed reactions at high temperatures results in carbonized and less-defined structures. Moreover, metal impurities affect the physicochemical, optical and electrical properties of the synthesized frameworks, dramatically. In this work, two-dimensional C3N3 (2DC3N3) has been synthesized by in situ catalyst-free copolymerization of sodium cyanide and cyanuric chloride, as cheap and commercially available precursors, at ambient conditions on gram scale. Reaction between sodium cyanide and cyanuric chloride resulted in electron-poor polyfunctional intermediates, which converted to 2DC3N3 with several hundred micrometers lateral size at ambient conditions upon [2 + 2+2] cyclotrimerization. 2DC3N3 sheets, in bulk and individually, showed strong fluorescence with 63% quantum yield and sensitive to small objects such as dyes and metal ions. The sensitivity of 2DC3N3 emission to foreign objects was used to detect low concentration of water impurities. Due to the high negative surface charge (-37.7 mV) and dispersion in aqueous solutions, they demonstrated a high potential to remove positively charged dyes from water, exemplified by excellent removal efficiency (>99%) for methylene blue. Taking advantage of the straightforward production and strong interactions with dyes and metal ions, 2DC3N3 was integrated in filters and used for the fast detection and efficient removal of water impurities.

Nanomechanical Spectroscopy of 2D Materials.

We introduce a nanomechanical platform for fast and sensitive measurements of the spectrally resolved optical dielectric function of 2D materials. At the heart of our approach is a suspended 2D material integrated into a high Q silicon nitride nanomechanical resonator illuminated by a wavelength-tunable laser source. From the heating-related frequency shift of the resonator as well as its optical reflection measured as a function of photon energy, we obtain the real and imaginary parts of the dielectric function. Our measurements are unaffected by substrate-related screening and do not require any assumptions on the underling optical constants. This fast (τrise ∼ 135 ns), sensitive (noise-equivalent power = 90⁣pW√Hz), and broadband (1.2-3.1 eV, extendable to UV-THz) method provides an attractive alternative to spectroscopic or ellipsometric characterization techniques.

Caregivers' Experiences During the COVID-19 Pandemic and Their Children's Behavior.

The COVID-19 pandemic has financial and emotional impacts on families. We explored how caregivers' financial strain and mental health are associated with changes in their young children's behavior during the pandemic. We additionally considered whether having a sense of purpose moderated these associations. Caregivers (n = 300) in the emergency department of a children's hospital were surveyed anonymously about changes to their employment (e.g., reduced/increased hours and job loss), ability to pay for expenses and whether their child's behavior had changed. Aligned with the Family Stress Model, caregivers' financial strain was associated with poor mental health, inconsistent sleep routines, and changes in children's problematic and prosocial behaviors. A sense of purpose buffered some of these relationships. Families are differently affected by the pandemic and our findings underscore the need for supporting caregivers' mental health and connecting them with resources.

Plasmonic nanolaser based on a single oligomer.

We investigate the effect of manipulating the laser quality factor and the spectral properties of the gain medium on an oligomer-based plasmonic nanolaser. We develop different designs of the oligomer resonators, decreasing the lasing threshold and increasing the mode lifetime to improve the lasing efficiency. Based on the designs we are able to decrease the lasing threshold by a factor of ten. We discuss and show numerically the influence of the oligomer geometry, the lasing mode oscillation lifetime, and the photoluminescence peak linewidth of the gain medium on the lasing efficiency of the oligomer based plasmonic nanolaser.

Moiré-Induced Vibrational Coupling in Double-Walled Carbon Nanotubes.

Moiré patterns are additional, long-range periodicities in twisted crystalline bilayers. They are known to fundamentally change the electronic states of the layers, but similar effects on their mechanical and vibrational properties have not been discussed so far. Here we show that the moiré potential shifts the radial breathing mode in double-walled carbon nanotubes (DWCNTs). The change in frequency is expected to be proportional to the shift in optical transition energies, which are induced by the moiré patterns. To verify our model, we performed resonance Raman scattering on purified and sorted semiconducting DWCNTs. We find that the radial breathing mode shifts up to 14 cm-1 higher in energy followed by displacement of optical transition energies of up to 200 meV to lower energies, in comparison to the single-walled tubes. We show how to identify the strong coupling condition in DWCNTs from their phonon frequencies and construct a Kataura plot to aid their future experimental assignment.

Challenging Parenting Behaviors in Ethnically Diverse Two-Parent Families in the United States: Association with Infants' Social Competence and Behavior Problems.

We used data from a sample of ethnically diverse first-time parents (N = 186) in the United States to examine differences between mothers' and fathers' challenging parenting behaviors (CPB) when infants were 9 months old as well as covariates of CPB. We also examined associations between CPB and infants' social competence and behavior problems when they were 12 months old. Results showed no differences between mothers and fathers in the level of CPB with their infants. Mothers with more depressive symptoms engaged in more CPB. Over and above the contributions of infants' gender and temperament and parents' education, mothers' and fathers' CPB was not associated with infants' social competence and behavior problems. This study expands our understanding of the universality of CPB and whether it is associated with social competence in ethnically diverse families.

A Randomized Control Trial of Using Baby Books to Reduce New Mothers' Feelings of Stress and Depression.

OBJECTIVE: To determine whether embedding educational information about child development and optimal parenting practices from the Bright Futures Guidelines for Health Supervision into baby books can reduce women's depressive symptoms and parenting stress during the first 18 months of motherhood. METHODS: A sample of 167 low-income, primarily African-American, first-time mothers were randomized into three conditions while pregnant: an educational book group, a non-educational book group, or a no-book group. Depressive symptoms and parenting stress were assessed using two questionnaires during home visits when women were in their third trimester of pregnancy (baseline) and when their child was 2, 4, 6, 9, 12, and 18 months of age. RESULTS: Hierarchical Linear Models showed that women who received books with educational information shed depressive symptoms and parenting stress at a faster rate than women who received similar books without educational information and women who did not receive books. CONCLUSIONS: These findings indicate that providing women with child development and parenting information via baby books can be an effective strategy for promoting new mothers' emotional wellbeing. Since feelings of sadness and stress are risky for both mothers and their infants, this easy to implement intervention holds great promise.

Raman Scattering Cross Section of Confined Carbyne.

We experimentally quantify the Raman scattering from individual carbyne chains confined in double-walled carbon nanotubes. We find that the resonant differential Raman cross section of confined carbyne is on the order of 10-22 cm2 sr-1 per atom, making it the strongest Raman scatterer ever reported.

Few-Wall Carbon Nanotube Coils.

While various electronic components based on carbon nanotubes (CNTs) have already been demonstrated, the realization of miniature electromagnetic coils based on CNTs remains a challenge. Coils made of single-wall CNTs with accessible ends for contacting have been recently demonstrated but were found unsuitable to act as electromagnetic coils because of electrical shorting between their turns. Coils made of a few-wall CNT could in principle allow an insulated flow of current and thus be potential candidates for realizing CNT-based electromagnetic coils. However, no such CNT structure has been produced so far. Here, we demonstrate the formation of few-wall CNT coils and characterize their structural, optical, vibrational, and electrical properties using experimental and computational tools. The coils are made of CNTs with 2, 3, or 4 walls. They have accessible ends for electrical contacts and low defect densities. The coil diameters are on the order of one micron, like those of single-wall CNT coils, despite the higher rigidity of few-wall CNTs. Coils with as many as 163 turns were found, with their turns organized in a rippled raft configuration. These coils are promising candidates for a variety of miniature devices based on electromagnetic coils, such as electromagnets, inductors, transformers, and motors. Being chirally and enantiomerically pure few-wall CNT bundles, they are also ideal for fundamental studies of interwall coupling and superconductivity in CNTs.

Best friends, bad food, and bullying: How students' school perceptions relate to sense of school belonging.

A positive school climate and sense of school belonging can influence students' academic outcomes and wellbeing in desirable ways. However, not enough is known about the aspects of school climate that influence students' feelings of belonging and how gender, ethnicity, and grade may relate to those feelings. Via a self-administered survey, a diverse sample of middle school students (n = 1,226) reported what they perceived as the best parts of their school and the parts most in need of improvement, as well as their sense of belonging. Students' perceptions of their school were aligned with the major areas of school climate: safety, relationships, teaching and learning, and institutional environment. These four areas were found to be predictive of sense of belonging to different degrees, such as listing relationships as needing improvement at the school being associated with lower scores in sense of belonging. Gender and grade were also found to be salient predictors of feelings of belonging, with seventh and eighth graders feeling less belonging than their sixth grade peers and girls having lower sense of belonging than boys. These findings affirm the importance of the school environment in influencing students' feelings of being a part of their school.

Understanding the Electron-Doping Mechanism in Potassium-Intercalated Single-Walled Carbon Nanotubes.

Single-walled carbon nanotubes (SWCNTs) can be doped with potassium, similar to graphite, leading to intercalation compounds. These binary systems exhibit a clear metallic character. However, the entire picture of how electron doping (e-doping) modifies the SWCNTs' vibrational spectra as a function of their diameter, chirality, and metallicity is still elusive. Herein, we present a detailed study of the intercalation and solid state reduction of metallic and semiconducting enriched HiPco SWCNTs. We performed a combined experimental and theoretical study of the evolution of their Raman response with potassium exposure, focusing specifically on their radial breathing mode (RBM). We found the charge donated from the potassium atoms occupies antibonding π orbitals of the SWCNTs, weakening their C-C bonds, and reducing the RBM frequency. This RBM downshift with increasing doping level is quasi-linear with a steplike behavior when the Fermi level crosses a van Hove singularity for semiconducting species. Moreover, this weakening of the C-C bonds is greater with decreasing curvature, or increasing diameter. Overall, this suggests the RBM downshift with e-doping is proportional to both the SWCNT's integrated density of states (DOS) ϱ(ε) and diameter d. We have provided a precise and complete description of the complex electron doping mechanism in SWCNTs up to a charge density of -18 me/C, far beyond that achievable by standard gate voltage studies, not being the highest doping possible, but high enough to track the effects of doping in SWCNTs based on their excitation energy, diameter, band gap energy, chiral angle, and metallicity. This work is highly relevant to tuning the electronic properties of SWCNTs for applications in nanoelectronics, plasmonics, and thermoelectricity.

Selective excitation of localized surface plasmons by structured light.

We investigated the selective excitation of localized surface plasmons by structured light. We derive selection rules using group theory and propose a fitting integral to quantify the contribution of the eigenmodes to the absorption spectra. Based on the result we investigate three nano oligomers of different symmetry (trimer, quadrumer, and hexamer) in detail using finite-difference time-domain simulations. We show that by controlling the incident light polarization and phase pattern we are able to control the absorption and scattering spectra. Additionally, we demonstrate that the fitting between the incident light and the oligomer modes may favor a number of modes to oscillate. Dark modes produce strong changes in the absorption spectrum and bright modes in the scattering spectrum. The experimental precision (axial shift error) may be on the same order as the oligomer diameter making the orbital angular momentum selection rules robust enough for experimental observation.

Dark plasmon modes for efficient hot electron generation in multilayers of gold nanoparticles.

The excitation of dark plasmons, i.e., coupled plasmon modes with a vanishing net dipole, is expected to favor Landau damping over radiative damping. Dark plasmon excitation might, therefore, lead to an increased absorption of energy within gold nanoparticles, resulting in a strong generation of hot electrons compared to the generation via bright plasmons. We performed transient-absorption spectroscopy on gold nanoparticle films to assess the initial electronic temperature before thermalization. We observe a significant increase in the electron-phonon coupling time when dark plasmon modes are excited in these films. The results indicate an efficient energy absorption due to the suppressed radiative decay of dark plasmon modes and a subsequent energy transformation into hot electrons.

Direct optical excitation of dark plasmons for hot electron generation.

An ideal plasmonic system for hot-electron generation allows the optical excitation of plasmons, limits radiation losses, exhibits strong non-radiative electron damping, and is made from scalable and cost-effective materials. Here we demonstrate the optical excitation of dark interlayer plasmons in bilayers of colloidal gold nanoparticles. This excitation is created by an antiparallel orientation of the dipole moments in the nanoparticle layers; it is expected to exhibit strongly reduced radiative damping. Despite the vanishing dipole moment, an incoming electromagnetic wave that is propagating normal to the surface will excite the dark mode due to field retardation. We observe a strong peak in the absorption spectrum of a colloidal gold bilayer (nanoparticle diameter = 46 nm); this peak is absent for a nanoparticle monolayer. The full width at half maximum of the dark mode is 230 meV for an ideal nanoparticle crystal and 320 meV for the structure produced by self-assembly out of solution. The position and width of the dark plasmon are efficiently tailored by the interparticle distance within the layer, nanoparticle size and layer number. We present time-resolved pump and probe experiments of hot-electron generation by bright and dark bilayer nanoparticle modes.

"It's Just a Lot of Work": Adolescents' Self-Presentation Norms and Practices on Facebook and Instagram.

We explored adolescents' (12- to 18-year-olds; n = 51) awareness of their audience and subsequent self-presentation practices on Facebook and Instagram through focus group discussions. Findings suggest that teens, who are developmentally able to perceive a situation from the third-person perspective and who value peer approval, purposefully share content to appear interesting, well liked, and attractive. Some teens invested great effort into posting by these norms, even asking their friends to help; however, this was more common among girls. Older teens especially discussed taking the perspective of their audience when deciding what to post, which is consistent with the finding that perspective taking continues to develop throughout adolescence. These findings suggest that perspective taking skills and need for peer approval influence self-presentation online.