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1.
Cienc. act. fís. (Talca, En línea) ; 24(1): 1-12, jun. 2023. tab
Artigo em Espanhol | LILACS | ID: biblio-1513953

RESUMO

La inteligencia emocional se define como habilidades para conocer y dominar emociones propias y de otros/as. Los objetivos del presente estudio fueron validar un instrumento de inteligencia emocional en una muestra de estudiantes de Educación Física de Chile y describir las habilidades emocionales de la muestra. Se evaluaron 226 estudiantes de Educación Física de dos universidades de Santiago de Chile. Se aplicó la Escala rasgo de metaconocimiento emocional (TMMS-24). Los resultados revelan que el instrumento, reducido a 19 ítems, presenta tres factores que explican el 56,8% de la varianza total, con un alfa de Cronbach de 0,916. En relación con los niveles de inteligencia emocional, la muestra presenta valores altos, sin que existan diferencias significativas en las dimensiones claridad, atención y reparación del TMMS-24 entre damas y varones. Al comparar por años de carrera, sólo hay diferencias en la dimensión claridad, donde los/as estudiantes de 5º año poseen mayores puntajes que los/as de 2º. Se concluye que los/as estudiantes de Educación Física poseen altos índices de inteligencia emocional, sin diferencias entre damas y varones.


Emotional intelligence is defined as the ability to know and master one's and/or others' emotions. The objectives of this study were to validate an emotional intelligence instrument in a sample of physical education students from Chile, and to describe the emotional skills of the sample. 226 physical education students from two universities in Santiago de Chile were evaluated. The Emotional Metacognition Trait Scale (TMMS-24) was applied. The results reveal that the instrument, reduced to 19 items, presents three factors that explain 56,8% of the total variance, with a Cronbach alpha of 0,916. In relation to the levels of emotional intelligence, the sample presents high values, without there being significant differences in the dimension's clarity, attention, and repair of the TMMS-24 between women and men. When comparing years of career, there are only differences in the clarity dimension, where 5th year students had higher scores than/as 2nd years. It is concluded that physical education students have high rates of emotional intelligence, with no differences between women and men.


A inteligência emocional é definida como habilidades para conhecer e dominar emoções próprias e de outros/as. Os objetivos do presente estudo foram validar um instrumento de inteligência emocional em uma mostra de estudantes de Educação Física do Chile e descrever as habilidades emocionais da mostra. Foram avaliados 226 estudantes de Educação Física de duas universidades de Santiago do Chile. Foi aplicada a Escala característica de meta-conhecimento emocional (TMMS-24). Os resultados revelam que o instrumento, reduzido a 19 itens, apresenta três fatores que explicam 56,8% da variância total, com um alfa de Cronbach de 0,916. Em relação aos níveis de inteligência emocional, a amostra apresenta valores altos, sem que existam diferenças significativas nas dimensões clareza, atenção e reparação do TMMS-24 entre mulheres e homens. Ao comparar por anos de carreira, só há diferenças na dimensão clareza, onde os/as estudantes de 5º ano possuem maiores pontuações que os/as de 2º. Conclui-se que os/as estudantes de Educação Física possuem altos índices de inteligência emocional, sem diferenças entre mulheres e homens.


Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Adulto Jovem , Educação Física e Treinamento/tendências , Modelos Estatísticos , Estudantes/psicologia , Universidades , Chile , Compreensão , Análise de Sentimentos
2.
Nat Commun ; 14(1): 122, 2023 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-36653337

RESUMO

Large-scale events like the UEFA Euro 2020 football (soccer) championship offer a unique opportunity to quantify the impact of gatherings on the spread of COVID-19, as the number and dates of matches played by participating countries resembles a randomized study. Using Bayesian modeling and the gender imbalance in COVID-19 data, we attribute 840,000 (95% CI: [0.39M, 1.26M]) COVID-19 cases across 12 countries to the championship. The impact depends non-linearly on the initial incidence, the reproduction number R, and the number of matches played. The strongest effects are seen in Scotland and England, where as much as 10,000 primary cases per million inhabitants occur from championship-related gatherings. The average match-induced increase in R was 0.46 [0.18, 0.75] on match days, but important matches caused an increase as large as +3. Altogether, our results provide quantitative insights that help judge and mitigate the impact of large-scale events on pandemic spread.


Assuntos
COVID-19 , Futebol , Humanos , Teorema de Bayes , COVID-19/epidemiologia , Inglaterra , Escócia
3.
J Phys Chem B ; 127(3): 717-731, 2023 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-36629314

RESUMO

A vibration's transition frequency is partly determined by the first-order Stark effect, which accounts for the electric field experienced by the mode. Using ultrafast infrared pump-probe and FT-IR spectroscopies, we characterized both the 0 → 1 and 1 → 2 vibrational transitions' field-dependent peak positions and line widths of the CN stretching mode of benzonitrile (BZN) and phenyl selenocyanate (PhSeCN) in ten solvents. We present a theoretical model that decomposes the observed line width into a field-dependent Stark contribution and a field-independent non-Stark solvent coupling contribution (NSC). The model demonstrates that the field-dependent peak position is independent of the line width, even when the NSC dominates the latter. Experiments show that when the Stark tuning rate is large compared to the NSC (PhSeCN), the line width has a field dependence, albeit with major NSC-induced excursions from linearity. When the Stark tuning rate is small relative to the NSC (BZN), the line width is field-independent. BZN's line widths are substantially larger for the 1 → 2 transition, indicating a 1 → 2 transition enhancement of the NSC. Additionally, we examine, theoretically and experimentally, the difference in the 0 → 1 and 1 → 2 transitions' Stark tuning rates. Second-order perturbation theory combined with density functional theory explain the difference and show that the 1 → 2 transition's Stark tuning rate is ∼10% larger. The Stark tuning rate of PhSeCN is larger than BZN's for both transitions, consistent with the theoretical calculations. This study provides new insights into vibrational line shape components and a more general understanding of the vibrational response to external electric fields.

4.
Int J Surg Case Rep ; 100: 107770, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36334547

RESUMO

INTRODUCTION AND IMPORTANCE: Incisional hernias are among the most frequent complications of abdominal surgery, with an incidence of 4-10 % of patients [1]. The multidisciplinary approach according to the patient's needs and their comorbidities has been shown to improve postoperative outcomes. This case report highlights the importance of a multidisciplinary approach including cardiology, general surgery, plastic surgery anesthesiology and intensive care unit for abdominal wall reconstruction in a patient with heart failure and reduced ejection fraction. CLINICAL PRESENTATION: We present a case of a 61-year-old patient with long-standing incisional hernia, without surgical correction due to the patient's condition and multiple comorbidities, advanced heart failure with reduced left ejection fraction (10-15 %) who underwent a multidisciplinary approach by cardiology, plastic surgery, anesthesiology, intensive care unit, and general surgery. DISCUSSION: The patient underwent abdominal wall reconstruction without complications. Due to multiple comorbidities, the patient was admitted in the ICU in the immediate postoperative period. He was discharged 9 days after surgery. The patient did not report long-term complications. CONCLUSION: Heart failure is associated with an increased risk of cardiovascular complications during surgical hospitalization. In patients with multiple comorbidities, the multidisciplinary approach represents an essential strategy in order to improve the surgical outcome, reduce costs to the health care system, and improve the patient's quality of life.

5.
Front Mol Biosci ; 9: 898627, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35911960

RESUMO

Computational methods in protein engineering often require encoding amino acid sequences, i.e., converting them into numeric arrays. Physicochemical properties are a typical choice to define encoders, where we replace each amino acid by its value for a given property. However, what property (or group thereof) is best for a given predictive task remains an open problem. In this work, we generalize property-based encoding strategies to maximize the performance of predictive models in protein engineering. First, combining text mining and unsupervised learning, we partitioned the AAIndex database into eight semantically-consistent groups of properties. We then applied a non-linear PCA within each group to define a single encoder to represent it. Then, in several case studies, we assess the performance of predictive models for protein and peptide function, folding, and biological activity, trained using the proposed encoders and classical methods (One Hot Encoder and TAPE embeddings). Models trained on datasets encoded with our encoders and converted to signals through the Fast Fourier Transform (FFT) increased their precision and reduced their overfitting substantially, outperforming classical approaches in most cases. Finally, we propose a preliminary methodology to create de novo sequences with desired properties. All these results offer simple ways to increase the performance of general and complex predictive tasks in protein engineering without increasing their complexity.

6.
J Transl Med ; 20(1): 373, 2022 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-35982500

RESUMO

BACKGROUND: Recently, extensive cancer genomic studies have revealed mutational and clinical data of large cohorts of cancer patients. For example, the Pan-Lung Cancer 2016 dataset (part of The Cancer Genome Atlas project), summarises the mutational and clinical profiles of different subtypes of Lung Cancer (LC). Mutational and clinical signatures have been used independently for tumour typification and prediction of metastasis in LC patients. Is it then possible to achieve better typifications and predictions when combining both data streams? METHODS: In a cohort of 1144 Lung Adenocarcinoma (LUAD) and Lung Squamous Cell Carcinoma (LSCC) patients, we studied the number of missense mutations (hereafter, the Total Mutational Load TML) and distribution of clinical variables, for different classes of patients. Using the TML and different sets of clinical variables (tumour stage, age, sex, smoking status, and packs of cigarettes smoked per year), we built Random Forest classification models that calculate the likelihood of developing metastasis. RESULTS: We found that LC patients different in age, smoking status, and tumour type had significantly different mean TMLs. Although TML was an informative feature, its effect was secondary to the "tumour stage" feature. However, its contribution to the classification is not redundant with the latter; models trained using both TML and tumour stage performed better than models trained using only one of these variables. We found that models trained in the entire dataset (i.e., without using dimensionality reduction techniques) and without resampling achieved the highest performance, with an F1 score of 0.64 (95%CrI [0.62, 0.66]). CONCLUSIONS: Clinical variables and TML should be considered together when assessing the likelihood of LC patients progressing to metastatic states, as the information these encode is not redundant. Altogether, we provide new evidence of the need for comprehensive diagnostic tools for metastasis.


Assuntos
Adenocarcinoma de Pulmão , Carcinoma Pulmonar de Células não Pequenas , Carcinoma de Células Escamosas , Neoplasias Pulmonares , Adenocarcinoma de Pulmão/genética , Adenocarcinoma de Pulmão/patologia , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma de Células Escamosas/genética , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Mutação/genética
7.
Adv Stat Anal ; 106(3): 399-402, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35698579
8.
J. health med. sci. (Print) ; 8(2): 105-108, abr.-jun. 2022. ilus
Artigo em Espanhol | LILACS | ID: biblio-1391923

RESUMO

OBJETIVO: comparar la kinesioterapia tradicional con la técnica miofacial en pacientes con restricción articular interna glenohumeral. MÉTODO: estudio comparativo de 8 pacientes en un grupo de intervención (GI) y kinésico (GC), durante 8 semanas. Se comparó el pre y post test del ROM interno glenohumeral en ambos grupos mediante t de student. RESULTADOS: el grupo de la técnica miofascial demostró una amento significativo de ROM interno glenohumeral de 15,2º (p < 0,001), mientras que el grupo control no fue significativo (p > 0,05) sólo de de 6,4º. CONCLUSIONES:Un tratamiento de terapia con la Técnicas Liberación Miofascial en pacientes con déficit rotacional interno de hombro es más eficaz para aumentar el rango de movimiento articular de rotación interna glenohumeral que una técnica tradicional y conservadora.


OBJETIVE: to compare traditional kinesiotherapy with myofacial technique in patients with glenohumeral internal joint restriction. METHODS: comparative study of 8 patients in an intervention (IG) and kinesiotherapy (CG) group for 8 weeks. The pre- and post-test of glenohumeral internal ROM in both groups was compared using Student's t-test. RESULTS: the myofascial technique group showed a significant increase in glenohumeral internal ROM of 15.2º (p < 0.001), while the control group was not significant (p > 0.05) only 6.4º. CONCLUSIONS: A therapy treatment with Myofascial Release Techniques in patients with shoulder internal rotational deficit is more effective in increasing glenohumeral internal rotational joint range of motion than a traditional, conservative technique.


Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Pessoa de Meia-Idade , Adulto Jovem , Articulação do Ombro/fisiopatologia , Amplitude de Movimento Articular , Terapia de Liberação Miofascial , Artropatias/reabilitação , Rotação , Resultado do Tratamento
9.
Front Nutr ; 9: 831696, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35252308

RESUMO

A growing body of evidence indicates that dietary polyphenols could be used as an early intervention to treat glucose-insulin (G-I) dysregulation. However, studies report heterogeneous information, and the targets of the intervention remain largely elusive. In this work, we provide a general methodology to quantify the effects of any given polyphenol-rich food or formulae over glycemic regulation in a patient-wise manner using an Oral Glucose Tolerance Test (OGTT). We use a mathematical model to represent individual OGTT curves as the coordinated action of subsystems, each one described by a parameter with physiological interpretation. Using the parameter values calculated for a cohort of 1198 individuals, we propose a statistical model to calculate the risk of dysglycemia and the coordination among subsystems for each subject, thus providing a continuous and individual health assessment. This method allows identifying individuals at high risk of dysglycemia-which would have been missed with traditional binary diagnostic methods-enabling early nutritional intervention with a polyphenol-supplemented diet where it is most effective and desirable. Besides, the proposed methodology assesses the effectiveness of interventions over time when applied to the OGTT curves of a treated individual. We illustrate the use of this method in a case study to assess the dose-dependent effects of Delphinol® on reducing dysglycemia risk and improving the coordination between subsystems. Finally, this strategy enables, on the one hand, the use of low-cost, non-invasive methods in population-scale nutritional studies. On the other hand, it will help practitioners assess the effectiveness of an intervention based on individual vulnerabilities and adapt the treatment to manage dysglycemia and avoid its progression into disease.

12.
Rev. colomb. gastroenterol ; 36(4): 494-500, oct.-dic. 2021.
Artigo em Inglês, Espanhol | LILACS | ID: biblio-1360974

RESUMO

Resumen La coledocolitiasis secundaria es una entidad de alta prevalencia que involucra desafíos de diagnóstico y tratamiento; asimismo, genera un elevado uso de recursos y costo económico. Existen múltiples vacíos de conocimiento con respecto a los modelos de predicción clínica para el diagnóstico, estratificación en grupos de riesgo y manejo de pacientes con coledocolitiasis secundaria. Los principales vacíos recaen sobre su rendimiento diagnóstico, variables incluidas y umbrales de riesgo, así como sobre su costo-efectividad para el uso de recursos no invasivos e invasivos, y aplicación en grupos poblacionales especiales. Este artículo ahonda estos vacíos de conocimiento y propone una agenda que puede orientar la investigación futura.


Abstract Secondary choledocholithiasis is a disease of high prevalence that involves diagnostic and treatment challenges; it implies a high use of resources and economic costs. There are significant knowledge gaps related to clinical prediction models, risk group classification, and patient treatment in secondary choledocholithiasis cases. Those gaps include diagnostic performance, variables, and risk thresholds, as well as cost-effectiveness for the use of non-invasive and invasive resources, and their application in special population groups. This study analyzes those knowledge gaps and outlines a guideline that could lead future research.


Assuntos
Humanos , Risco , Coledocolitíase , Diagnóstico , Previsões , Pacientes , Efetividade , Grupos de Risco , Prevalência , Custos e Análise de Custo
13.
Sci Adv ; 7(41): eabg2243, 2021 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-34623913

RESUMO

The traditional long-term solutions for epidemic control involve eradication or population immunity. Here, we analytically derive the existence of a third viable solution: a stable equilibrium at low case numbers, where test-trace-and-isolate policies partially compensate for local spreading events and only moderate restrictions remain necessary. In this equilibrium, daily cases stabilize around ten or fewer new infections per million people. However, stability is endangered if restrictions are relaxed or case numbers grow too high. The latter destabilization marks a tipping point beyond which the spread self-accelerates. We show that a lockdown can reestablish control and that recurring lockdowns are not necessary given sustained, moderate contact reduction. We illustrate how this strategy profits from vaccination and helps mitigate variants of concern. This strategy reduces cumulative cases (and fatalities) four times more than strategies that only avoid hospital collapse. In the long term, immunization, large-scale testing, and international coordination will further facilitate control.

14.
PLoS Comput Biol ; 17(9): e1009288, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34473693

RESUMO

Mass vaccination offers a promising exit strategy for the COVID-19 pandemic. However, as vaccination progresses, demands to lift restrictions increase, despite most of the population remaining susceptible. Using our age-stratified SEIRD-ICU compartmental model and curated epidemiological and vaccination data, we quantified the rate (relative to vaccination progress) at which countries can lift non-pharmaceutical interventions without overwhelming their healthcare systems. We analyzed scenarios ranging from immediately lifting restrictions (accepting high mortality and morbidity) to reducing case numbers to a level where test-trace-and-isolate (TTI) programs efficiently compensate for local spreading events. In general, the age-dependent vaccination roll-out implies a transient decrease of more than ten years in the average age of ICU patients and deceased. The pace of vaccination determines the speed of lifting restrictions; Taking the European Union (EU) as an example case, all considered scenarios allow for steadily increasing contacts starting in May 2021 and relaxing most restrictions by autumn 2021. Throughout summer 2021, only mild contact restrictions will remain necessary. However, only high vaccine uptake can prevent further severe waves. Across EU countries, seroprevalence impacts the long-term success of vaccination campaigns more strongly than age demographics. In addition, we highlight the need for preventive measures to reduce contagion in school settings throughout the year 2021, where children might be drivers of contagion because of them remaining susceptible. Strategies that maintain low case numbers, instead of high ones, reduce infections and deaths by factors of eleven and five, respectively. In general, policies with low case numbers significantly benefit from vaccination, as the overall reduction in susceptibility will further diminish viral spread. Keeping case numbers low is the safest long-term strategy because it considerably reduces mortality and morbidity and offers better preparedness against emerging escape or more contagious virus variants while still allowing for higher contact numbers (freedom) with progressing vaccinations.


Assuntos
Vacinas contra COVID-19 , COVID-19 , Vacinação em Massa , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , COVID-19/epidemiologia , COVID-19/prevenção & controle , Criança , Pré-Escolar , União Europeia/estatística & dados numéricos , Humanos , Lactente , Recém-Nascido , Vacinação em Massa/legislação & jurisprudência , Vacinação em Massa/estatística & dados numéricos , Pessoa de Meia-Idade , Adulto Jovem
15.
J Phys Chem B ; 125(31): 8907-8918, 2021 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-34339200

RESUMO

Ultrafast infrared vibrational spectroscopy is widely used for the investigation of dynamics in systems from water to model membranes. Because the experimental observation window is limited to a few times the probe's vibrational lifetime, a frequent obstacle for the measurement of a broad time range is short molecular vibrational lifetimes (typically a few to tens of picoseconds). Five new long-lifetime aromatic selenocyanate vibrational probes have been synthesized and their vibrational properties characterized. These probes are compared to commercial phenyl selenocyanate. The vibrational lifetimes range between ∼400 and 500 ps in complex solvents, which are some of the longest room-temperature vibrational lifetimes reported to date. In contrast to vibrations that are long-lived in simple solvents such as CCl4, but become much shorter in complex solvents, the probes discussed here have ∼400 ps lifetimes in complex solvents and even longer in simple solvents. One of them has a remarkable lifetime of 1235 ps in CCl4. These probes have a range of molecular sizes and geometries that can make them useful for placement into different complex materials due to steric reasons, and some of them have functionalities that enable their synthetic incorporation into larger molecules, such as industrial polymers. We investigated the effect of a range of electron-donating and electron-withdrawing para-substituents on the vibrational properties of the CN stretch. The probes have a solvent-independent linear relationship to the Hammett substituent parameter when evaluated with respect to the CN vibrational frequency and the ipso 13C NMR chemical shift.


Assuntos
Compostos de Selênio , Vibração , Cianatos , Espectrofotometria Infravermelho
16.
J Chem Phys ; 154(24): 244104, 2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-34241361

RESUMO

The theoretical framework for reorientation-induced spectral diffusion (RISD) describes the polarization dependence of spectral diffusion dynamics as measured with two-dimensional (2D) correlation spectroscopy and related techniques. Generally, RISD relates to the orientational dynamics of the molecular chromophore relative to local electric fields of the medium. The predictions of RISD have been shown to be very sensitive to both restricted orientational dynamics (generally arising from steric hindrance) and the distribution of local electric fields relative to the probe (electrostatic ordering). Here, a theory that combines the two effects is developed analytically and supported with numerical calculations. The combined effects can smoothly vary the polarization dependence of spectral diffusion from the purely steric case (least polarization dependence) to the purely electrostatic case (greatest polarization dependence). Analytic approximations of the modified RISD equations were also developed using the orientational dynamics of the molecular probe and two order parameters describing the degree of electrostatic ordering. It was found that frequency-dependent orientational dynamics are a possible consequence of the combined electrostatic and steric effects, providing a test for the applicability of this model to experimental systems. The modified RISD equations were then used to successfully describe the anomalous polarization-dependent spectral diffusion seen in 2D infrared spectroscopy in a polystyrene oligomer system that exhibits frequency-dependent orientational dynamics. The degree of polarization-dependent spectral diffusion enables the extent of electrostatic ordering in a chemical system to be quantified and distinguished from steric ordering.

17.
18.
J Am Chem Soc ; 143(9): 3583-3594, 2021 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-33630576

RESUMO

The size, size distribution, dynamics, and electrostatic properties of free volume elements (FVEs) in polystyrene (PS) and poly(methyl methacrylate) (PMMA) were investigated using the Restricted Orientation Anisotropy Method (ROAM), an ultrafast infrared spectroscopic technique. The restricted orientational dynamics of a vibrational probe embedded in the polymer matrix provides detailed information on FVE sizes and their probability distribution. The probe's orientational dynamics vary as a function of its frequency within the inhomogeneously broadened vibrational absorption spectrum. By characterizing the degree of orientational restriction at different probe frequencies, FVE radii and their probability distribution were determined. PS has larger FVEs and a broader FVE size distribution than PMMA. The average FVE radii in PS and PMMA are 3.4 and 3.0 Å, respectively. The FVE radius probability distribution shows that the PS distribution is non-Gaussian, with a tail to larger radii, whereas in PMMA, the distribution is closer to Gaussian. FVE structural dynamics, previously unavailable through other techniques, occur on a ∼150 ps time scale in both polymers. The dynamics involve FVE shape fluctuations which, on average, conserve the FVE size. FVE radii were associated with corresponding electric field strengths through the first-order vibrational Stark effect of the CN stretch of the vibrational probe, phenyl selenocyanate (PhSeCN). PMMA displayed unique measured FVE radii for each electric field strength. By contrast, PS showed that, while larger radii correspond to unique and relatively weak electric fields, the smallest measured radii map onto a broad distribution of strong electric fields.

19.
Nat Commun ; 12(1): 378, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-33452267

RESUMO

Without a cure, vaccine, or proven long-term immunity against SARS-CoV-2, test-trace-and-isolate (TTI) strategies present a promising tool to contain its spread. For any TTI strategy, however, mitigation is challenged by pre- and asymptomatic transmission, TTI-avoiders, and undetected spreaders, which strongly contribute to "hidden" infection chains. Here, we study a semi-analytical model and identify two tipping points between controlled and uncontrolled spread: (1) the behavior-driven reproduction number [Formula: see text] of the hidden chains becomes too large to be compensated by the TTI capabilities, and (2) the number of new infections exceeds the tracing capacity. Both trigger a self-accelerating spread. We investigate how these tipping points depend on challenges like limited cooperation, missing contacts, and imperfect isolation. Our results suggest that TTI alone is insufficient to contain an otherwise unhindered spread of SARS-CoV-2, implying that complementary measures like social distancing and improved hygiene remain necessary.


Assuntos
Teste para COVID-19/métodos , COVID-19/prevenção & controle , Busca de Comunicante/métodos , Programas de Rastreamento/métodos , SARS-CoV-2/isolamento & purificação , Algoritmos , COVID-19/epidemiologia , COVID-19/virologia , Controle de Doenças Transmissíveis/métodos , Humanos , Modelos Teóricos , Pandemias , Reprodutibilidade dos Testes , SARS-CoV-2/fisiologia
20.
J Chem Phys ; 153(20): 204201, 2020 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-33261482

RESUMO

The infrared pulses used to generate nonlinear signals from a vibrational probe can cause heating via solvent absorption. Solvent absorption followed by rapid vibrational relaxation produces unwanted heat signals by creating spectral shifts of the solvent and probe absorptions. The signals are often isolated by "chopping," i.e., alternately blocking one of the incident pulses. This method is standard in pump-probe transient absorption experiments. As less heat is deposited into the sample when an incident pulse is blocked, the heat-induced spectral shifts give rise to artificial signals. Here, we demonstrate a new method that eliminates heat induced signals using pulse shaping to control pulse spectra. This method is useful if the absorption spectrum of the vibrational probe is narrow compared to the laser bandwidth. By using a pulse shaper to selectively eliminate only frequencies of light resonant with the probe absorption during the "off" shot, part of the pulse energy, and the resulting heat, is delivered to the solvent without generating the nonlinear signal. This partial heating reduces the difference heat signal between the on and off shots. The remaining solvent heat signal can be eliminated by reducing the wings of the on shot spectrum while still resonantly exciting the probe; the heat deposition from the on shot can be matched with that from the off shot, eliminating the solvent heat contribution to the signal. Modification of the pulse sequence makes it possible to measure only the heat signal, permitting the kinetics of heating to be studied.

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