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Bi2Te3, as a topological insulator, is able to support plasmonic emission in the visible spectral range. Thin Bi2Te3 flakes can be exfoliated directly from a Bi2Te3 crystal, and the shape of Bi2Te3 flakes can be further modified by focused ion beam milling. Therefore, we have designed a Bi2Te3 triangular antenna with distinct tip angles for the application of plasmonic resonance. The plasmonic emission of the Bi2Te3 triangular antenna is excited and investigated by cathodoluminescence in the scanning electron microscope. Enhanced tip plasmons have been observed from distinct tips with angles of 20º, 36º, 54º, 70º, and 90º, respectively. Due to the confinement of geometric boundaries for oscillating charges, the resonant peak position of tip plasmon with a smaller angle has a blue shift. Moreover, the dependence of plasmonic behavior on the excitation position has been discovered as well. This research provides a unique approach to fabricate Bi2Te3 nanostructures and manipulate the corresponding plasmonic properties. [ABSTRACT FROM AUTHOR]

The ability to predict nucleic acid hybridization energies has been greatly enabling for many applications, but predictive models require painstaking experimentation, which may limit expansion to non-natural nucleic acid analogues and chemistries. We have assessed the utility of dye-based, high-resolution melting (HRM) as an alternative to UV-Vis determinations of hyperchromicity in order to more quickly acquire parameters for duplex stability prediction. The HRM-derived model for phosphodiester (PO) DNA can make comparable predictions to previously established models. Using HRM, it proved possible to develop predictive models for DNA duplexes containing phosphorothioate (PS) linkages, and we found that hybridization stability could be predicted as a function of sequence and backbone composition for a variety of duplexes, including PS:PS, PS:PO, and partially modified backbones. Individual phosphorothioate modifications destabilize helices by around 0.12 kcal/mol on average. Finally, we applied these models to the design of a catalytic hairpin assembly circuit, an enzyme-free amplification method used for nucleic acid-based molecular detection. Changes in PS circuit behavior were consistent with model predictions, further supporting the addition of HRM modeling and parameters for PS oligonucleotides to the rational design of nucleic acid hybridization. [ABSTRACT FROM AUTHOR]

Background: There remains uncertainty about the impact of the Coronavirus Disease 2019 (COVID-19) pandemic on mental health. This umbrella review provides a comprehensive overview of the association between the pandemic and common mental disorders. We qualitatively summarized evidence from reviews with meta-analyses of individual study-data in the general population, healthcare workers, and specific at-risk populations. Methods and findings: A systematic search was carried out in 5 databases for peer-reviewed systematic reviews with meta-analyses of prevalence of depression, anxiety, and post-traumatic stress disorder (PTSD) symptoms during the pandemic published between December 31, 2019 until August 12, 2022. We identified 123 reviews of which 7 provided standardized mean differences (SMDs) either from longitudinal pre- to during pandemic study-data or from cross-sectional study-data compared to matched pre-pandemic data. Methodological quality rated with the Assessment of Multiple Systematic Reviews checklist scores (AMSTAR 2) instrument was generally low to moderate. Small but significant increases of depression, anxiety, and/or general mental health symptoms were reported in the general population, in people with preexisting physical health conditions, and in children (3 reviews; SMDs ranged from 0.11 to 0.28). Mental health and depression symptoms significantly increased during periods of social restrictions (1 review; SMDs of 0.41 and 0.83, respectively) but anxiety symptoms did not (SMD: 0.26). Increases of depression symptoms were generally larger and longer-lasting during the pandemic (3 reviews; SMDs depression ranged from 0.16 to 0.23) than those of anxiety (2 reviews: SMDs 0.12 and 0.18). Females showed a significantly larger increase in anxiety symptoms than males (1 review: SMD 0.15). In healthcare workers, people with preexisting mental disorders, any patient group, children and adolescents, and in students, no significant differences from pre- to during pandemic were found (2 reviews; SMD's ranging from −0.16 to 0.48). In 116 reviews pooled cross-sectional prevalence rates of depression, anxiety, and PTSD symptoms ranged from 9% to 48% across populations. Although heterogeneity between studies was high and largely unexplained, assessment tools and cut-offs used, age, sex or gender, and COVID-19 exposure factors were found to be moderators in some reviews. The major limitations are the inability to quantify and explain the high heterogeneity across reviews included and the shortage of within-person data from multiple longitudinal studies. Conclusions: A small but consistent deterioration of mental health and particularly depression during early pandemic and during social restrictions has been found in the general population and in people with chronic somatic disorders. Also, associations between mental health and the pandemic were stronger in females and younger age groups than in others. Explanatory individual-level, COVID-19 exposure, and time-course factors were scarce and showed inconsistencies across reviews. For policy and research, repeated assessments of mental health in population panels including vulnerable individuals are recommended to respond to current and future health crises. Anke B Witteveen and colleagues synthesise evidence from 123 systematic reviews investigating mental health outcomes during the COVID-19 pandemic. Author summary: Why was this study done?: The Coronavirus Disease 2019 (COVID-19) pandemic has been one of the greatest global public health challenges of the last century and has impacted multiple aspects of health and public life. An adverse association between the pandemic and global mental health was expected and many research projects have been rapidly developed to assess this. There is uncertainty about the degree and extent of the associations between the pandemic and its associated measures and mental health. What do these findings mean?: This umbrella review could help clinicians, researchers, and policy makers to better understand the current evidence on the association between the COVID-19 pandemic and mental health, particularly in specific vulnerable subpopulations. The interpretability of the included systematic reviews was limited by the great variation in prevalence rates and associations between studies and because of the scarcity of longitudinal data. Policy makers and researchers should address common pitfalls of research designs prior to implementation of systematic mental health assessments in future population panels. What did the researchers do and find?: We synthesized evidence from 123 systematic reviews of individual studies on symptoms of common mental disorders, including depression, anxiety, and PTSD, in general and specific populations and in healthcare workers. Seven reviews compared differences in mental health outcomes during the COVID-19 pandemic or during implementation of public health and social measures to pre-pandemic periods or periods with minimal restrictions. Another 116 reviews provided combined data on during pandemic prevalence rates of mental health outcomes. Mental health and particularly mood of the general population slightly deteriorated in the first half year of the pandemic, and symptom increases were associated with periods of public health measures and social restrictions. Also, people with preexisting physical health conditions, females, and young people showed pandemic-associated increases in symptoms. Variation in pandemic-associated mental health prevalence rates between individual studies was large and often unexplained. In several reviews, methodological, individual-level, and COVID-19 exposure factors did explain some of the variation but in others this was not the case. Quality of the systematic reviews was poor to moderate. [ABSTRACT FROM AUTHOR]

Phosphorus (P) is an essential element for crop production and a key source of nonpoint pollution in agroecosystems. In this study, we sought to analyze P levels and the factors affecting soil P availability, via P adsorption, in a typical field system that is characterized by the year-round cultivation of vegetables. A total of 190 sites were sampled from vegetable fields in Guangdong Province, South China. Within the research area, average concentrations of 124.49 mg P kg-1 and 1.55 g P kg-1 were recorded for available P (AP) and total P (TP), respectively, which are 8.53- and 1.78-fold higher, respectively, than the corresponding values recorded in 1980. The determined P adsorption maximum (Qm) averaged at 488.38 mg kg-1, which represents a reduction of 16% compared to the values obtained four decades ago. Accumulations of both TP and AP were found to be negatively correlated with the soil's maximum adsorption buffering capacity (MBC), although no significant correlations with the soil binding energies (k) and Qm, were seen. However, soil pH was found to be significantly correlated with k and Qm. Furthermore, both free Mn oxides (Mnd) and silt concentrations in the soil were found to contribute to explaining the variations in Qm. Collectively, the findings of this study provide evidence to indicate that there has been an excessive accumulation of P in the perennial vegetable fields of Guangdong Province over the past four decades, which may have had negative effects on the P supply potential of the soil by reducing the maximum adsorption buffering capacity. [ABSTRACT FROM AUTHOR]