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1.
Philos Trans A Math Phys Eng Sci ; 380(2224): 20210154, 2022 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-35400183

RESUMO

Motivated by recent successes in model-based pre-election polling, we propose a kinetic model for opinion formation which includes voter demographics and socio-economic factors like age, sex, ethnicity, education level, income and other measurable factors like behaviour in previous elections or referenda as a key driver in the opinion formation dynamics. The model is based on Toscani's kinetic opinion formation model (Toscani G. 2006 Kinetic models of opinion formation. Commun. Math. Sci. 4, 481-496.) and the leader-follower model of Düring et al. (Düring B. et al. 2009 Boltzmann and Fokker-Planck equations modelling opinion formation in the presence of strong leaders. Proc. R. Soc. A 465, 3687-3708.), and leads to a system of coupled Boltzmann-type equations and associated, approximate Fokker-Planck-type systems. Numerical examples using data from general elections in the UK show the effect different demographics have on the opinion formation process and the outcome of elections. This article is part of the theme issue 'Kinetic exchange models of societies and economies'.


Assuntos
Atitude , Cinética
2.
Health Expect ; 25(5): 2095-2106, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-34420254

RESUMO

OBJECTIVE: This study aimed to develop interpretive insights concerning Infection Prevention and Control (IPC) in care homes for older people. DESIGN: This study had a meta-ethnography design. DATA SOURCES: Six bibliographic databases were searched from inception to May 2020 to identify the relevant literature. REVIEW METHODS: A meta-ethnography was performed. RESULTS: Searches yielded 652 records; 15 were included. Findings were categorized into groups: The difficulties of enacting IPC measures in the care home environment; workload as an impediment to IPC practice; the tension between IPC and quality of life for care home residents; and problems dealing with medical services located outside the facility including diagnostics, general practice and pharmacy. Infection was revealed as something seen to lie 'outside' the control of the care home, whether according to origins or control measures. This could help explain the reported variability in IPC practice. Facilitators to IPC uptake involved repetitive training and professional development, although such opportunities can be constrained by the ways in which services are organized and delivered. CONCLUSIONS: Significant challenges were revealed in implementing IPC in care homes including staffing skills, education, workloads and work routines. These challenges cannot be properly addressed without resolving the tension between the objectives of maintaining resident quality of life while enacting IPC practice. Repetitive staff training and professional development with parallel organisational improvements have prospects to enhance IPC uptake in residential and nursing homes. PATIENT OR PUBLIC CONTRIBUTION: A carer of an older person joined study team meetings and was involved in writing a lay summary of the study findings.


Assuntos
Casas de Saúde , Qualidade de Vida , Humanos , Idoso , Pesquisa Qualitativa , Atenção à Saúde , Antropologia Cultural
3.
Nano Lett ; 21(14): 6261-6267, 2021 07 28.
Artigo em Inglês | MEDLINE | ID: mdl-34279964

RESUMO

High-frequency surface phonons have a myriad of applications in telecommunications and sensing, but their generation and detection have often been limited to transducers occupying micron-scale regions because of the use of two-dimensional transducer arrays. Here, by means of transient reflection spectroscopy we experimentally demonstrate optically coupled nanolocalized gigahertz surface phonon transduction based on a gold nanowire emitter arranged parallel to linear gold nanorod receiver arrays, that is, quasi-one-dimensional emitter-receivers. We investigate the response up to 10 GHz of these individual optoacoustic and acousto-optic transducers, respectively, by exploiting plasmon-polariton longitudinal resonances of the nanorods. We also demonstrate how the surface phonon detection efficiency is highly dependent on the nanorod orientation with respect to the phonon wave vector, which constrains the symmetry of the detectable modes, and on the nanorod acoustic resonance spectrum. Applications include nanosensing.


Assuntos
Nanoestruturas , Nanotubos , Ouro , Fônons , Transdutores
4.
Clin Otolaryngol ; 47(6): 650-655, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35899971

RESUMO

INTRODUCTION: Investigation of head and neck cancers places a significant burden on the National Health Service and effective resource allocation is of perpetual importance. Existing risk calculators are designed to stratify the likelihood of underlying malignancy according to symptoms, but are less relevant in secondary care as they do not integrate clinical examination findings (e.g. naso-endoscopy). We looked to evaluate the utility of magnetic resonance imaging (MRI) in investigating patients with unilateral odynophagia and a normal clinical examination. METHODS: A retrospective analysis was conducted over a 54-month period; 484 consecutively-recruited adult patients who underwent MRI of the neck for suspected malignancy were included. Imaging reports, case notes, and histopathology results were reviewed. Patients with previously diagnosed/treated malignancy, undergoing surveillance, or those with pathology of the salivary glands, oral cavity or thyroid gland, were excluded. A multivariate binary logistical regression model was performed to calculate the odds ratios and probabilities of malignancy for each presenting symptom, with and without negative nasoendoscopy findings. RESULTS: The overall incidence of malignancy within the cohort was 173/484 patients (35.7%; 95% CI 31.5%-40.2%) with no cases of malignancy in patients presenting with odynophagia and a normal nasoendoscopy (0/39). The presence of a neck lump was significantly associated with malignancy, (odds ratio [OR] 2.03, p = .001; 95% CI 1.59-2.58), as was dysphagia (OR 1.52, p = .009; 95% CI 1.11-2.11). Conversely, globus was found to have an inverse association (OR 0.41, p < .001; 95% CI 0.24-0.70). SUMMARY: New patients presenting with odynophagia alone and normal endoscopy or globus have a low likelihood of underlying malignancy, justifying reassurance and follow-up in the event of persistent symptoms. Contrariwise, patients with a neck lump, dysphagia, odynophagia and multiple concurrent aerodigestive tract symptoms, or an abnormal endoscopy have a high likelihood of underlying malignancy and should be investigated accordingly.


Assuntos
Transtornos de Deglutição , Neoplasias de Cabeça e Pescoço , Adulto , Transtornos de Deglutição/diagnóstico por imagem , Transtornos de Deglutição/etiologia , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Humanos , Modelos Logísticos , Imageamento por Ressonância Magnética , Estudos Retrospectivos , Medicina Estatal
5.
Br J Nurs ; 29(1): 50-54, 2020 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-31917945

RESUMO

INTRODUCTION: access to water at the bedside is a cornerstone of patient care. Among bedbound inpatients, water within reach at the bedside is a basic human dignity and one that ought not to be neglected. AIM: the authors sought to identify the extent to which accessible hydration facilities were provided to a bedbound inpatient population. METHODS: a cross-sectional, point-prevalent audit of hospitalised medical inpatients across five centres was conducted. Data were collected between meal times and noted baseline demographics and admission details, adequacy of oral hydration provision at the bedside and, where provision was inadequate, factors associated with this. RESULTS: across a total surveyed patient population of 559 we identified 138 patients who were bedbound. Among these bedbound patients, 6% (n=8) had no water provided at the bedside. However, 7 of these were deemed to be unable to swallow safely. In total, 44 (32%) of the 138 bedbound patients were unable to reach the water at their bedside; 18 of these patients would have been able to drink for themselves had the water been in reach. CONCLUSION: there is significant room for improvement in ensuring patients who are immobile are able to reach drinking apparatus at the bedside. In the five centres surveyed, approximately one in five bedbound patients with no contraindication are unable to reach an essential means of hydration.


Assuntos
Auditoria Clínica , Desidratação/prevenção & controle , Água Potável , Hospitalização , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Inglaterra , Feminino , Hospitais Gerais , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Medicina Estatal , Adulto Jovem
6.
Muscle Nerve ; 59(3): 370-379, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30414320

RESUMO

INTRODUCTION: The morphological characteristics of skeletal muscles innervated caudal to a spinal cord injury (SCI) undergo dramatic phenotypic and microvascular changes. METHOD: Female Sprague-Dawley rats received a severe contusion at thoracic level 9/10 and were randomly assigned to locomotor training, epidural stimulation, or a combination of the treatment groups (CB). Fiber type composition and capillary distribution were assessed in phenotypically distinct compartments of the tibialis anterior. RESULTS: Spinal cord injury induced a shift in type II fiber phenotype from oxidative to glycolytic (P < 0.05) as well as capillary loss within the oxidative core and glycolytic cortex; the CB treatment best maintained capillary supply within both compartments. DISCUSSION: The angiogenic response of CB training improved capillary distribution across the muscle; capillary distribution became spatially more homogeneous and mean capillary supply area decreased, potentially improving oxygenation. There is an important role for weight-bearing training in maintaining the oxidative phenotype of muscle after SCI. Muscle Nerve 59:370-379, 2019.


Assuntos
Capilares/patologia , Terapia por Exercício/métodos , Condicionamento Físico Animal/métodos , Traumatismos da Medula Espinal/patologia , Traumatismos da Medula Espinal/reabilitação , Animais , Atrofia , Estimulação Elétrica , Espaço Epidural , Feminino , Imuno-Histoquímica , Locomoção , Fibras Musculares de Contração Rápida/metabolismo , Fibras Musculares de Contração Rápida/patologia , Músculo Esquelético/irrigação sanguínea , Músculo Esquelético/patologia , Neovascularização Fisiológica , Projetos Piloto , Ratos , Ratos Sprague-Dawley , Recuperação de Função Fisiológica
7.
Phys Rev Lett ; 120(4): 044302, 2018 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-29437440

RESUMO

Effective transmission of sound from water to air is crucial for the enhancement of the detection sensitivity of underwater sound. However, only 0.1% of the acoustic energy is naturally transmitted at such a boundary. At audio frequencies, quarter-wave plates or multilayered antireflection coatings are too bulky for practical use for such enhancement. Here we present an acoustic metasurface of a thickness of only ∼λ/100, where λ is the wavelength in air, consisting of an array of meta-atoms that each contain a set of membranes and an air-filled cavity. We experimentally demonstrate that such a meta-atom increases the transmission of sound at ∼700 Hz by 2 orders of magnitude, allowing about 30% of the incident acoustic power from water to be transmitted into air. Applications include underwater sonic sensing and communication.

8.
Nano Lett ; 17(11): 6684-6689, 2017 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-28915056

RESUMO

Using polarization-resolved transient reflection spectroscopy, we investigate a metasurface consisting of coherently vibrating nanophotonic U-shaped split-ring meta-atoms that exhibit colocalized optical and mechanical resonances. With an array of these resonators formed of gold on glass, essentially miniature tuning forks, we monitor the visible-pump induced gigahertz oscillations in reflected infrared light intensity to probe the multimodal vibrational response. Numerical simulations of the associated transient deformations and strain fields elucidate the complex nanomechanical dynamics contributing to the ultrafast optical modulation and point to the role of acousto-plasmonic interactions through the opening and closing motion of the SRR gaps as the dominant effect. Applications include ultrafast acoustooptic modulator design and sensing.

9.
Lancet ; 385(9980): 1873-83, 2015 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-25882396

RESUMO

BACKGROUND: Treatment for patients with chronic lymphocytic leukaemia who are elderly or who have comorbidities is challenging because fludarabine-based chemoimmunotherapies are mostly not suitable. Chlorambucil remains the standard of care in many countries. We aimed to investigate whether the addition of ofatumumab to chlorambucil could lead to better clinical outcomes than does treatment with chlorambucil alone, while also being tolerable for patients who have few treatment options. METHODS: We carried out a randomised, open-label, phase 3 trial for treatment-naive patients with chronic lymphocytic leukaemia in 109 centres in 16 countries. We included patients who had active disease needing treatment, but in whom fludarabine-based treatment was not possible. We randomly assigned patients (1:1) to receive oral chlorambucil (10 mg/m(2)) on days 1-7 of a 28 day treatment course or to receive chlorambucil by this schedule plus intravenous ofatumumab (cycle 1: 300 mg on day 1 and 1000 mg on day 8; subsequent cycles: 1000 mg on day 1) for three to 12 cycles. Assignment was done with a randomisation list that was computer generated at GlaxoSmithKline, and was stratified, in a block size of two, by age, disease stage, and performance status. The primary endpoint was progression-free survival in the intention-to-treat population and assessment was done by an independent review committee that was masked to group assignment. The study is registered with ClinicalTrials.gov, number NCT00748189. FINDINGS: We enrolled 447 patients, median age 69 years (range 35-92). Between Dec 22, 2008, and May 26, 2011, we randomly assigned 221 patients to chlorambucil plus ofatumumab and 226 patients to chlorambucil alone. Median progression-free survival was 22·4 months (95% CI 19·0-25·2) in the group assigned to chlorambucil plus ofatumumab compared with 13·1 months (10·6-13·8) in the group assigned to chlorambucil only (hazard ratio 0·57, 95% CI 0·45-0·72; p<0·0001). Grade 3 or greater adverse events were more common in the chlorambucil plus ofatumumab group (109 [50%] patients; vs 98 [43%] given chlorambucil alone), with neutropenia being the most common event (56 [26%] vs 32 [14%]). Grade 3 or greater infections had similar frequency in both groups. Grade 3 or greater infusion-related adverse events were reported in 22 (10%) patients given chlorambucil plus ofatumumab. Five (2%) patients died during treatment in each group. INTERPRETATION: Addition of ofatumumab to chlorambucil led to clinically important improvements with a manageable side-effect profile in treatment-naive patients with chronic lymphocytic leukaemia who were elderly or had comorbidities. Chlorambucil plus ofatumumab is therefore an important treatment option for these patients who cannot tolerate more intensive therapy. FUNDING: GlaxoSmithKline, Genmab A/S.


Assuntos
Antineoplásicos Alquilantes/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Clorambucila/uso terapêutico , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Adulto , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/efeitos adversos , Anticorpos Monoclonais Humanizados , Antineoplásicos Alquilantes/administração & dosagem , Antineoplásicos Alquilantes/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Clorambucila/administração & dosagem , Clorambucila/efeitos adversos , Esquema de Medicação , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Distribuição por Sexo , Resultado do Tratamento
10.
Am J Hematol ; 91(9): 900-6, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27222473

RESUMO

The purpose of this study is to assess the safety and efficacy of the combination of ofatumumab and bendamustine in patients with previously untreated or relapsed chronic lymphocytic leukemia. Patients received IV ofatumumab (cycle 1: 300 mg day 1 and 1,000 mg day 8; cycles 2-6: 1,000 mg on day 1 every 28 days) and IV bendamustine 90 mg m(-2) (previously untreated) or 70 mg m(-2) (relapsed) on days 1 and 2 of each 28-day cycle, for up to 6 cycles. Forty-four previously untreated and 53 relapsed patients were enrolled. Median age was 62.5 years (previously untreated) and 68 years (relapsed); relapsed patients had received a median of 1 (range 1-11) prior therapy. The investigator-assessed overall response rate was 95% (43% complete response [CR]) for the previously untreated, and 74% (11% CR) for the relapsed patients. The regimen was well tolerated with 89% (previously untreated) and 85% (relapsed patients) receiving all 6 cycles. No unexpected toxicities were reported. Grade 3/4 events occurred in 57% of previously untreated, and 72% of relapsed patients. At ∼29 months' follow-up, the median progression-free survival (PFS) was not reached for the previously untreated population, and the 28-month PFS estimate was 72.3%. The median PFS for the relapsed population was 22.5 months (95% CI: 14.0-27.3 months). The combination of ofatumumab and bendamustine was well tolerated and effective in these previously untreated or relapsed populations. Am. J. Hematol. 91:900-906, 2016. © 2016 Wiley Periodicals, Inc.


Assuntos
Anticorpos Monoclonais/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Cloridrato de Bendamustina/administração & dosagem , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais Humanizados , Intervalo Livre de Doença , Esquema de Medicação , Feminino , Humanos , Leucemia Linfocítica Crônica de Células B/mortalidade , Masculino , Pessoa de Meia-Idade , Recidiva , Indução de Remissão/métodos , Resultado do Tratamento
11.
Opt Lett ; 40(10): 2157-60, 2015 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-26393688

RESUMO

Using an ultrafast optical technique with enhanced frequency control, we image surface-acoustic whispering-gallery-like modes in a microscopic disk at various frequencies up to 1 gigahertz (GHz), allowing experimental determination of their dispersion. This is made possible by intensity-modulated optical pumping and probing with a periodic femtosecond light source. Spatiotemporal Fourier transforms of the two-dimensional acoustic fields measured to micron resolution allow us to isolate individual whispering-gallery modes of first and second radial order as well as their mode patterns and Q factors to unprecedented frequency resolution. We thereby demonstrate arbitrary-frequency ultrafast control and imaging of a micro-acoustic system with an optical time-resolved technique. Applications include quality control of surface acoustic wave filters in telecommunications.

12.
Philos Trans A Math Phys Eng Sci ; 373(2049)2015 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-26217053

RESUMO

In this paper, we review results obtained by ultrafast imaging of gigahertz surface acoustic waves in surface phononic crystals with one- and two-dimensional periodicities. By use of quasi-point-source optical excitation, we show how, from a series of images that form a movie of the travelling waves, the dispersion relation of the acoustic modes, their corresponding mode patterns and the position and widths of phonon stop bands can be obtained by temporal and spatio-temporal Fourier analysis. We further demonstrate how one can follow the temporal evolution of phononic eigenstates in k-space using data from phononic-crystal waveguides as an example.

14.
PLoS One ; 19(1): e0296049, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38295034

RESUMO

Pandemics such as Covid-19 pose tremendous public health communication challenges in promoting protective behaviours, vaccination, and educating the public about risks. Segmenting audiences based on attitudes and behaviours is a means to increase the precision and potential effectiveness of such communication. The present study reports on such an audience segmentation effort for the population of England, sponsored by the United Kingdom Health Security Agency (UKHSA) and involving a collaboration of market research and academic experts. A cross-sectional online survey was conducted between 4 and 24 January 2022 with 5525 respondents (5178 used in our analyses) in England using market research opt-in panel. An additional 105 telephone interviews were conducted to sample persons without online or smartphone access. Respondents were quota sampled to be demographically representative. The primary analytic technique was k means cluster analysis, supplemented with other techniques including multi-dimensional scaling and use of respondent - as well as sample-standardized data when necessary to address differences in response set for some groups of respondents. Identified segments were profiled against demographic, behavioural self-report, attitudinal, and communication channel variables, with differences by segment tested for statistical significance. Seven segments were identified, including distinctly different groups of persons who tended toward a high level of compliance and several that were relatively low in compliance. The segments were characterized by distinctive patterns of demographics, attitudes, behaviours, trust in information sources, and communication channels preferred. Segments were further validated by comparing the segmentation variable versus a set of demographic variables as predictors of reported protective behaviours in the past two weeks and of vaccine refusal; the demographics together had about one-quarter the effect size of the single seven-level segment variable. With respect to managerial implications, different communication strategies for each segment are suggested for each segment, illustrating advantages of rich segmentation descriptions for understanding public health communication audiences. Strengths and weaknesses of the methods used are discussed, to help guide future efforts.


Assuntos
COVID-19 , Comunicação em Saúde , Humanos , COVID-19/epidemiologia , COVID-19/prevenção & controle , Pandemias/prevenção & controle , Estudos Transversais , Vacinação
15.
J Surg Case Rep ; 2024(1): rjae004, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38283413

RESUMO

Cranial suture diastases are an uncommon clinical entity, with post craniotomy diastases being a previously undescribed finding in literature to our best knowledge. Herein, we report a case of a 28-year-old adult who underwent a second-stage low-grade glioma surgery 7 months after initial surgery. This study presents coronal suture diastases adjacent to the previously performed craniotomy. After literature and pathophysiology review, we found it to be unique and that the craniotomy can resemble the mechanical stress of trauma.

16.
Microbiology (Reading) ; 159(Pt 7): 1221-1235, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23519158

RESUMO

As the field of synthetic biology develops, real-world applications are moving from the realms of ideas and laboratory-confined research towards implementation. A pressing concern, particularly with microbial systems, is that self-replicating re-engineered cells may produce undesired consequences if they escape or overwhelm their intended environment. To address this biosafety issue, multiple mechanisms for constraining microbial replication and horizontal gene transfer have been proposed. These include the use of host-construct dependencies such as toxin-antitoxin pairs, conditional plasmid replication or the requirement for a specific metabolite to be present for cellular function. While refactoring of the existing genetic code or tailoring of orthogonal systems, e.g. xeno nucleic acids, offers future promise of more stringent 'firewalls' between natural and synthetic cells, here we focus on what can be achieved using existing technology. The state-of-the-art in designing for biosafety is summarized and general recommendations are made (e.g. short environmental retention times) for current synthetic biology projects to better isolate themselves against potentially negative impacts.


Assuntos
Bactérias/genética , Engenharia Genética/efeitos adversos , Biologia Sintética/métodos , Engenharia Genética/métodos , Organismos Geneticamente Modificados/genética , Xenobióticos/efeitos adversos
17.
Phys Rev Lett ; 110(24): 244302, 2013 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-25165929

RESUMO

We demonstrate 97%, 89%, and 76% transmission of sound amplitude in air through walls perforated with subwavelength holes of areal coverage fractions 0.10, 0.03, and 0.01, respectively, producing 94-, 950-, and 5700-fold intensity enhancements therein. This remarkable level of extraordinary acoustic transmission is achieved with thin tensioned circular membranes, making the mass of the air in the holes effectively vanish. Imaging the pressure field confirms incident-angle independent transmission, thus realizing a bona fide invisible wall. Applications include high-resolution acoustic sensing.

18.
J Pept Sci ; 19(2): 74-83, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23255255

RESUMO

High-throughput screens that dispense with the need for expensive synthetic Aß peptide would be invaluable for identifying novel anti-aggregants as potential treatments for Alzheimer's disease. A biosynthetic in vivo approach, using a recombinant fluorescent green fluorescent protein (GFP) reporter for the aggregation state of Aß in Escherichia coli, has been reported by other workers. Here, inducible Aß-GFP expression in E. coli was coupled to the concurrent constitutive production of a quasi-random peptide library to screen for anti-aggregant activity. To attempt to introduce greater robustness, mCherry was also co-expressed as an internal fluorescence standard to allow ratiometric comparison between samples. However, fluctuations in mCherry expression levels, as well as a low dynamic range of GFP output between positive and negative anti-aggregant peptides, highlighted limitations with the approach. Despite this, two novel peptides were identified that showed an equivalent in vitro anti-aggregant activity to that of epigallocatechin-3-gallate. Thus, although biosynthetic in vivo strategies show promise as screens for novel activities, unforeseen problems can arise because of the variability inherent in any biological system.


Assuntos
Peptídeos beta-Amiloides/antagonistas & inibidores , Escherichia coli/metabolismo , Proteínas de Fluorescência Verde/análise , Ensaios de Triagem em Larga Escala/métodos , Medições Luminescentes/métodos , Fragmentos de Peptídeos/antagonistas & inibidores , Peptídeos/análise , Peptídeos/farmacologia , Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/metabolismo , Biologia Computacional , Escherichia coli/genética , Fluorescência , Proteínas de Fluorescência Verde/biossíntese , Proteínas de Fluorescência Verde/genética , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Biblioteca de Peptídeos , Ligação Proteica/efeitos dos fármacos
19.
Photoacoustics ; 30: 100459, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36852340

RESUMO

Time-domain Brillouin scattering (TDBS) is an all-optical experimental technique for investigating transparent materials based on laser picosecond ultrasonics. Its application ranges from imaging thin-films, polycrystalline materials and biological cells to physical properties such as residual stress, temperature gradients and nonlinear coherent nano-acoustic pulses. When the sample refractive index is spatially uniform and known in TDBS, analysis by windowed Fourier transforms allows one to depth-profile the sound velocity. Here, we present a new method in TDBS for extracting sound velocity without a knowledge of the refractive index, by use of probe light obliquely incident on a side face-as opposed to the usual top face-of the sample. We demonstrate this method using a fused silica sample with a titanium transducer film and map the sound velocity in the depth direction. In future, it should be possible to map the sound velocity distribution in three dimensions in inhomogeneous samples, with applications to the imaging of biological cells.

20.
Photoacoustics ; 31: 100486, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37113270

RESUMO

We present a picosecond optoacoustic technique for mapping both the longitudinal sound velocity v and the refractive index n in solids by automated measurement at multiple probe incidence angles in time-domain Brillouin scattering. Using a fused silica sample with a deposited titanium film as an optoacoustic transducer, we map v and n in the depth direction. Applications include the imaging of sound velocity and refractive index distributions in three dimensions in inhomogeneous samples such as biological cells.

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