Interactions Between Ultrashort Pulses and Laser-Produced Tin Plasmas

Inside commercial EUV nanolithography sources, micrometer-sized droplets of liquid tin are irradiated by a high-power CO2 laser, creating a plasma which emits the desired 13.5 nm light. However, small dense liquid spheres are an inefficient target shape for EUV production. To solve this, each droplet is irradiated by two laser pulses. Firstly, a low-energy pre-pulse irradiates the initially-spherical droplet, deforming it via hydrodynamic expansion into a shape more favourable for EUV production. Afterwards, a time-delayed high-energy main pulse irradiates this deformed droplet. Typically, pre-pulses with nanosecond durations are used to deform the target from a sphere into a thin disk. An alternative approach involves using pre-pulses with picosecond or femtosecond durations. These shorter pulses create an intense shock wave on the droplet surface, which propagates through the droplet focusing at its center, where a bubble is formed through a process called cavitation. This bubble rapidly expands, rupturing the droplet, which then breaks up into fine particles. These “cloud” targets have in some cases shown higher conversion efficiencies than disk targets, with the drawback of additional debris created by the violent transformation process. To study the dynamics of cloud targets, we designed and built a laser system capable of producing laser pulses with durations ranging from 220 fs to 100 ps. The system includes a 1064 nm source based on Nd:YVO4 and Nd:YAG, producing pulses with durations between 15 and 100 ps and energies of up to 180 mJ. This system can be used as a standalone source or as a pump for a 1.55 μm KTA-based optical parametric chirped pulse amplifier, producing pulses with durations from 220 fs to 10 ps, with energies up to 10.5 mJ. Ultrashort mJ-level pulses from the OPCPA were used to study the effects of pulse energy and duration on microdroplet deformation. The velocities of the cavitation expansion and of the ablated material are found to decrease for longer pulses, indicating shorter pulses lead to faster, more violent dynamics. Using linearly-polarized pulses, cylindrically-asymmetric shock waves were produced, leading to novel asymmetric target shapes which show good qualitative agreement with smoothed-particle hydrodynamics simulations, highlighting the role of shock waves in the laser-driven deformation dynamics. Charge-state-resolved ion energy spectra were recorded using an electrostatic analyzer to study the processes that shape the energy of the ions emitted by the plasma. For lower laser energies we observe a linear relation between the mean ion energy of each charge state and its ionization number, a trend consistent with the typical electrostatic-driven ion acceleration model. For higher laser energies this relation becomes nonlinear, hinting at effects beyond the simple electrostatic acceleration model. Using the 1064 nm amplifier to irradiate droplet targets with a pair of 50-ps laser pulses, comprising a weaker first pulse with variable energy in the μJ range followed by a more energetic 5 mJ pulse, we produced novel target shapes which were keenly dependent on the energy of the first pulse and the time delay between the pulses. Furthermore, the addition of a small first pulse led to a significant reduction in the kinetic energy of the ions emitted by the plasma, with a 30-fold reduction in the most extreme case. Charge-state-resolved measurements show a reduction of ion kinetic energy for every charge state and a pronounced reduction in the yield of higher-charge-state ions, which are the most energetic. In certain pulse-pair configurations, it becomes possible to completely suppress higher charge states above Sn2+. This suppression of faster ions holds practical significance in extending the lifetime of optical components inside EUV sources when paired with ion mitigation techniques which are most effective for lower-energy ions

Controlling ion kinetic energy distributions in laser produced plasma sources by means of a picosecond pulse pair

The next generation of lithography machines uses extreme ultraviolet (EUV) light originating from laser-produced plasma (LPP) sources, where a small tin droplet is ionized by an intense laser pulse to emit the requested light at 13.5 nm. Numerous irradiation schemes have been explored to increase conversion efficiency (CE), out of which a double-pulse approach comprising a weak picosecond Nd:YAG pre-pulse followed by a powerful pulse is considered to be very promising [1]. Nevertheless, even for such CE-optimized schemes, ion debris ejected from the plasma with kinetic energies up to several keV remain a factor that hampers the maximum performance of LPP sources. In this letter we propose a novel pre-pulse scheme consisting of a picosecond pulse pair at 1064 nm, which decreases the amount of undesirable fast ions, avoids back-reflections to the lasers and enables one to tailor the target shape.Comment: 12 pages, 3 figures, 45 reference

Expansion Dynamics After Laser-Induced Cavitation in Liquid Tin Microdroplets

The cavitation-driven expansion dynamics of liquid tin microdroplets is investigated, set in motion by the ablative impact of a 15-ps laser pulse. We combine high-resolution stroboscopic shadowgraphy with an intuitive fluid dynamic model that includes the onset of fragmentation, and find good agreement between model and experimental data for two different droplet sizes over a wide range of laser pulse energies. The dependence of the initial expansion velocity on these experimental parameters is heuristically captured in a single power law. Further, the obtained late-time mass distributions are shown to be governed by a single parameter. These studies are performed under conditions relevant for plasma light sources for extreme-ultraviolet nanolithography.Comment: 7 pages, 6 figure

COVID-19 infodemic and impacts on the mental health of older people : cross-sectional multicenter survey study

Background: The COVID-19 pandemic received widespread media coverage due to its novelty, an early lack of data, and the rapid rise in deaths and cases. This excessive coverage created a secondary “infodemic” that was considered to be a serious public and mental health problem by the World Health Organization and the international scientific community. The infodemic particularly affected older individuals, specifically those who are vulnerable to misinformation due to political positions, low interpretive and critical analysis capacity, and limited technical-scientific knowledge. Thus, it is important to understand older people’s reaction to COVID-19 information disseminated by the media and the effect on their lives and mental health. Objective: We aimed to describe the profile of exposure to COVID-19 information among older Brazilian individuals and the impact on their mental health, perceived stress, and the presence of generalized anxiety disorder (GAD). Methods: This cross-sectional, exploratory study surveyed 3307 older Brazilians via the web, social networks, and email between July 2020 and March 2021. Descriptive analysis and bivariate analysis were performed to estimate associations of interest. Results: Major proportions of the 3307 participants were aged 60 to 64 years (n=1285, 38.9%), female (n=2250, 68.4%), and married (n=1835, 55.5%) and self-identified as White (n=2364, 71.5%). Only 295 (8.9%) had never started or completed a basic education. COVID-19 information was mainly accessed on television (n=2680, 81.1%) and social networks (n=1943, 58.8%). Television exposure was ≥3 hours in 1301 (39.3%) participants, social network use was 2 to 5 hours in 1084 (32.8%) participants, and radio exposure was ≥1 hour in 1223 (37%) participants. Frequency of exposure to social networks was significantly associated with perceived stress (P=.04) and GAD (P=.01). A Bonferroni post hoc test revealed significantly different perceived stress in participants who were exposed to social networks for 1 hour (P=.04) and those who had no exposure (P=.04). A crude linear regression showed that “some” social media use (P=.02) and 1 hour of exposure to social media (P<.001) were associated with perceived stress. Adjusting for sociodemographic variables revealed no associations with this outcome variable. In a crude logistic regression, some social media use (P<.001) and 2 to 5 hours of exposure to social media (P=.03) were associated with GAD. Adjusting for the indicated variables showed that some social network use (P<.001) and 1 hour (P=.04) and 2 to 5 hours (P=.03) of exposure to social media were associated with GAD. Conclusions: Older people, especially women, were often exposed to COVID-19–related information through television and social networks; this affected their mental health, specifically GAD and stress. Thus, the impact of the infodemic should be considered during anamnesis for older people, so that they can share their feelings about it and receive appropriate psychosocial care

a randomized comparative effectiveness trial

Funding Information: The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was sponsored by CUF and Pingo Doce, as part of the Menos Sal Portugal project, and with support from the Centro de Medicina Laboratorial Germano de Sousa. The sponsors did not play a role in the study design or the interpretation of the results. The study was also promoted by the CINTESIS@RISE (UIDB/4255/2020 and UIDP/4255/2020), NOVA Medical School of Universidade NOVA de Lisboa and supported by national funds through FCT Fundação para a Ciência e a Tecnologia, I.P., within the scope of the project “RISE-LA/P/0053/2020”. Publisher Copyright: Copyright © 2023 Moreira-Rosário, Ismael, Barreiros-Mota, Morais, Rodrigues, Castela, Mendes, Soares, da Costa, Oliveira, Henriques, Pinto, Pita, de Oliveira, Maciel, Serafim, Araújo, Rocha, Pestana, Silvestre, Marques, Faria, Polonia and Calhau.Introduction: Empowerment lifestyle programs are needed to reduce the risk of hypertension. Our study compared the effectiveness of two empowerment-based approaches toward blood pressure (BP) reduction: salt reduction-specific program vs. healthy lifestyle general program. Methods: Three hundred and eleven adults (median age of 44 years, IQR 34–54 years) were randomly assigned to a salt reduction (n = 147) or a healthy lifestyle program (n = 164). The outcome measures were urinary sodium (Na+) and potassium (K+) excretion, systolic (SBP) and diastolic (DBP) blood pressure, weight, and waist circumference. Results: There were no significant differences in primary and secondary outcomes between the two program groups. When comparing each program to baseline, the program focused on salt reduction was effective in lowering BP following a 12-week intervention with a mean change of −2.5 mm Hg in SBP (95% CI, −4.1 to −0.8) and − 2.7 mm Hg in DBP (95% CI, −3.8 to −1.5) in the intention-to-treat (ITT) analysis. In the complete-case (CC) analysis, the mean change was −2.1 mm Hg in SBP (95% CI, −3.7 to −0.5) and − 2.3 mm Hg in DBP (95% CI, −3.4 to −1.1). This effect increases in subjects with high-normal BP or hypertension [SBP − 7.9 mm Hg (95% CI, −12.5 to −3.3); DBP − 7.3 mm Hg (95% CI, −10.2 to −4.4)]. The healthy lifestyle group also exhibited BP improvements after 12 weeks; however, the changes were less pronounced compared to the salt reduction group and were observed only for DBP [mean change of −1.5 mm Hg (95% CI, −2.6 to −0.4) in ITT analysis and − 1.4 mm Hg (95% CI, −2.4 to −0.3) in CC analysis, relative to baseline]. Overall, improvements in Na+/K+ ratio, weight, and Mediterranean diet adherence resulted in clinically significant SBP decreases. Importantly, BP reduction is attributed to improved dietary quality, rather than being solely linked to changes in the Na+/K+ ratio. Conclusion: Salt-focused programs are effective public health tools mainly in managing individuals at high risk of hypertension. Nevertheless, in general, empowerment-based approaches are important strategies for lowering BP, by promoting health literacy that culminates in adherence to the Mediterranean diet and weight reduction.publishersversionpublishe

DIAGNÓSTICO PRECOCE DA DOENÇA DE ALZHEIMER: IMPORTÂNCIA E DESAFIOS.

Alzheimer's disease is a neurodegenerative disorder common in older people and its pathophysiology is not yet well explained, but it is known that genetic factors are involved in its development.&nbsp; It is a chronic pathology that presents senile plaques and is characterized by a progressive decline in cognitive function, with damage mainly to short-term memory, language, reasoning and critical judgment. In view of the epidemiological impact of Alzheimer's disease, this paper aims to address the importance of early diagnosis of the disease, in order to highlight the challenges faced in its diagnosis. The study was based on a literature review. The articles were selected for the study after searching the SciELO, PubMed and VHL databases.&nbsp; The descriptors used to find the related studies were "Alzheimer's Disease" and "Early Diagnosis".&nbsp; As a result, it was observed that early diagnosis of Alzheimer's disease is of paramount importance for adequate access to treatment, planning and preparing the family for future challenges, seeking emotional support, safety and adequate care. However, challenges such as intra-laboratory variability, overlap with other forms of dementia and high cost mean that early diagnosis using biomarkers is limited.A Doença de Alzheimer é um acometimento neurodegenerativo comum em pessoas com mais idade e sua fisiopatologia ainda não é bem explicada, mas sabe-se da carga genética envolvida em seu desenvolvimento. &nbsp;Trata-se de uma patologia crônica, que apresenta placas senis e é caracterizada pelo declínio progressivo da função cognitiva, com prejuízo principalmente da memória a curto prazo, linguagem, raciocínio e juízo crítico. Tendo em vista o impacto epidemiológico da Doença de Alzheimer, o presente trabalho objetiva abordar a importância do diagnóstico precoce da doença, de modo a evidenciar os desafios enfrentados em seu diagnóstico. O estudo foi desenvolvido a partir da revisão de literatura. Os artigos foram selecionados para compor o estudo após buscas das bases de dado SciELO, PubMed e BVS.&nbsp; Os descritores utilizados para encontrar os estudos relacionados foram “Doença de Alzheimer” e “Diagnóstico Precoce”.&nbsp; Como resultado, observou-se que diagnóstico precoce da Doença de Alzheimer é de suma importância para acesso adequado ao tratamento, planejamento e preparação da família para desafios futuros, busca por suporte emocional, segurança e cuidados adequados. No entanto, desafios como variabilidade intralaboratorial, sobreposição com outras formas de demência e alto custo fazem com que o diagnóstico precoce a partir do uso de biomarcadores seja limitado

Empowerment-based nutrition interventions on blood pressure: a randomized comparative effectiveness trial

IntroductionEmpowerment lifestyle programs are needed to reduce the risk of hypertension. Our study compared the effectiveness of two empowerment-based approaches toward blood pressure (BP) reduction: salt reduction-specific program vs. healthy lifestyle general program.MethodsThree hundred and eleven adults (median age of 44 years, IQR 34–54 years) were randomly assigned to a salt reduction (n = 147) or a healthy lifestyle program (n = 164). The outcome measures were urinary sodium (Na+) and potassium (K+) excretion, systolic (SBP) and diastolic (DBP) blood pressure, weight, and waist circumference.ResultsThere were no significant differences in primary and secondary outcomes between the two program groups. When comparing each program to baseline, the program focused on salt reduction was effective in lowering BP following a 12-week intervention with a mean change of −2.5 mm Hg in SBP (95% CI, −4.1 to −0.8) and − 2.7 mm Hg in DBP (95% CI, −3.8 to −1.5) in the intention-to-treat (ITT) analysis. In the complete-case (CC) analysis, the mean change was −2.1 mm Hg in SBP (95% CI, −3.7 to −0.5) and − 2.3 mm Hg in DBP (95% CI, −3.4 to −1.1). This effect increases in subjects with high-normal BP or hypertension [SBP − 7.9 mm Hg (95% CI, −12.5 to −3.3); DBP − 7.3 mm Hg (95% CI, −10.2 to −4.4)]. The healthy lifestyle group also exhibited BP improvements after 12 weeks; however, the changes were less pronounced compared to the salt reduction group and were observed only for DBP [mean change of −1.5 mm Hg (95% CI, −2.6 to −0.4) in ITT analysis and − 1.4 mm Hg (95% CI, −2.4 to −0.3) in CC analysis, relative to baseline]. Overall, improvements in Na+/K+ ratio, weight, and Mediterranean diet adherence resulted in clinically significant SBP decreases. Importantly, BP reduction is attributed to improved dietary quality, rather than being solely linked to changes in the Na+/K+ ratio.ConclusionSalt-focused programs are effective public health tools mainly in managing individuals at high risk of hypertension. Nevertheless, in general, empowerment-based approaches are important strategies for lowering BP, by promoting health literacy that culminates in adherence to the Mediterranean diet and weight reduction

SARS-CoV-2 introductions and early dynamics of the epidemic in Portugal

Genomic surveillance of SARS-CoV-2 in Portugal was rapidly implemented by the National Institute of Health in the early stages of the COVID-19 epidemic, in collaboration with more than 50 laboratories distributed nationwide. Methods By applying recent phylodynamic models that allow integration of individual-based travel history, we reconstructed and characterized the spatio-temporal dynamics of SARSCoV-2 introductions and early dissemination in Portugal. Results We detected at least 277 independent SARS-CoV-2 introductions, mostly from European countries (namely the United Kingdom, Spain, France, Italy, and Switzerland), which were consistent with the countries with the highest connectivity with Portugal. Although most introductions were estimated to have occurred during early March 2020, it is likely that SARS-CoV-2 was silently circulating in Portugal throughout February, before the first cases were confirmed. Conclusions Here we conclude that the earlier implementation of measures could have minimized the number of introductions and subsequent virus expansion in Portugal. This study lays the foundation for genomic epidemiology of SARS-CoV-2 in Portugal, and highlights the need for systematic and geographically-representative genomic surveillance.We gratefully acknowledge to Sara Hill and Nuno Faria (University of Oxford) and Joshua Quick and Nick Loman (University of Birmingham) for kindly providing us with the initial sets of Artic Network primers for NGS; Rafael Mamede (MRamirez team, IMM, Lisbon) for developing and sharing a bioinformatics script for sequence curation (https://github.com/rfm-targa/BioinfUtils); Philippe Lemey (KU Leuven) for providing guidance on the implementation of the phylodynamic models; Joshua L. Cherry (National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health) for providing guidance with the subsampling strategies; and all authors, originating and submitting laboratories who have contributed genome data on GISAID (https://www.gisaid.org/) on which part of this research is based. The opinions expressed in this article are those of the authors and do not reflect the view of the National Institutes of Health, the Department of Health and Human Services, or the United States government. This study is co-funded by Fundação para a Ciência e Tecnologia and Agência de Investigação Clínica e Inovação Biomédica (234_596874175) on behalf of the Research 4 COVID-19 call. Some infrastructural resources used in this study come from the GenomePT project (POCI-01-0145-FEDER-022184), supported by COMPETE 2020 - Operational Programme for Competitiveness and Internationalisation (POCI), Lisboa Portugal Regional Operational Programme (Lisboa2020), Algarve Portugal Regional Operational Programme (CRESC Algarve2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF), and by Fundação para a Ciência e a Tecnologia (FCT).info:eu-repo/semantics/publishedVersio