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1.
J Acoust Soc Am ; 155(1): 420-435, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-38240669

RESUMO

The Perseverance rover is carrying out an original acoustic experiment on Mars: the SuperCam microphone records the spherical acoustic waves generated by laser sparks at distances from 2 m to more than 8 m. These N-shaped acoustic waves scatter from the multiple local heterogeneities of the turbulent atmosphere. Therefore, large and random fluctuations of sound travel time and intensity develop as the waves cross the medium. The variances of the travel times and the scintillation index (normalized variance of the sound intensity) are studied within the mathematical formalism of the propagation of spherical acoustic waves through thermal turbulence to infer statistical properties of the Mars atmospheric temperature fluctuation field. The comparison with the theory is made by simplifying assumptions that do not include wind fluctuations and diffraction effects. Two Earth years (about one Martian year) of observations acquired during the maximum convective period (10:00-14:00 Mars local time) show a good agreement between the dataset and the formalism: the travel time variance diverges from the linear Chernov solution exactly where the density of occurrence of the first caustic reaches its maximum. Moreover, on average, waves travel faster than the mean speed of sound due to a fast path effect, which is also observed on Earth. To account for the distribution of turbulent eddies, several power spectra are tested and the best match to observation is obtained with a generalized von Karman spectrum with a shallower slope than the Kolmogorov cascade, ϕ(k)∝(1+k2L2)-4/3. It is associated with an outer scale of turbulence, L, of 11 cm at 2 m above the surface and a standard deviation of 6 K over 9 s for the temperature. These near-surface atmospheric properties are consistent with a weak to moderate wave scattering regime around noon with little saturation. Overall, this study presents an innovative and promising methodology to probe the near-surface atmospheric turbulence on Mars.

2.
Cerebrovasc Dis ; 49(1): 110-118, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32097908

RESUMO

BACKGROUND: In patients with suspected stroke, brain imaging is recommended in the acute phase for appropriate management and treatment. Both computed tomography (CT) and magnetic resonance imaging (MRI) are considered reasonable choices for initial brain imaging. When both techniques are available, choosing one or the other might be associated with specific factors related either to patients, stroke symptoms, and severity or management organization. METHODS: The study was performed within the STROKE 69 database, a population-based cohort of all adult patients with suspected stroke admitted in one of the emergency departments (ED), primary stroke center, or stroke center of the Rhône County, from November 2015 to December 2016. Patients were included if they were admitted within 24 h following either symptom onset or last known normal. To identify factors potentially associated with the choice of initial brain imaging, a multivariate logistic regression was performed. RESULTS: Among the 3,244 patients with suspected stroke enrolled in the STROKE69 cohort, 3,107 (95.8%) underwent brain imaging within the first 24 h after admission. Among those 74.6% underwent CT as initial imaging while 25.4% had an MRI. In multivariate analyses, several factors were associated with a lower probability of having an MRI as initial brain imaging versus CT. These were either patient characteristics: older age (>80 years old, OR 0.39 [95% CI 0.28-0.54]), preexisting disability (OR 0.55 [95% CI 0.36-0.84]), use of anticoagulants (OR 0.52 [95% CI 0.33-0.81]), stroke characteristics: stroke of unknown onset (OR 0.42 [95% CI 0.31-0.58]) or factors associated with overall management: onset-to-door time (>6 h, OR 0.38 [95% CI 0.23-0.60]), initial admission to ED (OR 0.02 [95% CI 0.02-0.04]) or intensive care unit (OR 0.01 [95% CI 0.001-0.08]), personal transport (OR 0.66 [95% CI 0.45-0.96]), and admission during working hours (OR 0.65 [95% CI 0.51-0.84]). CONCLUSIONS: Besides CT or MRI availability, a number of other parameters could influence the choice of first imaging in case of stroke suspicion. These are related to patient characteristics, type of stroke symptoms, and type of organization.


Assuntos
Angiografia Cerebral , Comportamento de Escolha , Angiografia por Tomografia Computadorizada , Imageamento por Ressonância Magnética , Imagem de Perfusão , Padrões de Prática Médica , Acidente Vascular Cerebral/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Adulto , Idoso , Idoso de 80 Anos ou mais , Tomada de Decisão Clínica , Bases de Dados Factuais , Feminino , França/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Seleção de Pacientes , Valor Preditivo dos Testes , Acidente Vascular Cerebral/epidemiologia
3.
J Acoust Soc Am ; 135(6): 3390-7, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24907802

RESUMO

The effect of self-similarity on acoustic and elastic wave propagation at normal incidence is investigated using Classical Cantor and Fibonacci multilayered structures. They are made of two sorts of orthotropic plies having differently oriented orthotropic axes with respect to the propagation direction. The properties of their transmission coefficient are presented using a unidirectional numerical model based on a transfer matrix formalism. It was found that stack self-similarity influences the acoustic transmission properties. Transmission coefficients of self-similar stacks present a self-similar shape and behavior. A self-similar process, applied to layer orientation allows multilayered stacks to be created. A thickness-equivalent model was developed to compare these structures with standard self-similar multilayers which are finally compared to periodic and random stacks. The transmission coefficient of a deterministic self-similar Fibonacci structure is similar to that of an averaged transmission coefficient of random stacks.

5.
Oncotarget ; 12(19): 1920-1936, 2021 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-34548908

RESUMO

Triple-negative breast cancer (TNBC) constitutes a very aggressive type of breast cancer with few options of cytotoxic chemotherapy available for them. A chemotherapy regimen comprising of doxorubicin hydrochloride and cyclophosphamide, followed by paclitaxel, known as AC-T, is approved for usage as an adjuvant treatment for this type of breast cancer. In this study we aimed to elucidate the role of KIF11 in TNBC progression throughout its inhibition by two synthetic small molecules containing the DHPM core (dihydropyrimidin-2(1H)-ones or -thiones), with the hypothesis that these inhibitors could be an interesting option of antimitotic drug used alone or as adjuvant therapy in association with AC. For this purpose, we evaluated the efficacy of DHPMs used as monotherapy or in combination with doxorubicin and cyclophosphamide, in Balbc-nude mice bearing breast cancer induced by MDA-MB-231, having AC-T as positive control. Our data provide extensive evidence to demonstrate that KIF11 inhibitors showed pronounced antitumor activity, acting in key points of tumorigenesis and cancer progression in in vivo xenograft model of triple negative breast cancer, like down-regulation of KIF11 and ALDH1-A1. Moreover, they didn't show the classic peripheral neuropathy characterized by impaired mobility, as it is common with paclitaxel use. These results suggest that the use of a MAP inhibitor in breast cancer regimen treatment could be a promising strategy to keep antitumoral activity reducing the side effects.

6.
J Acoust Soc Am ; 122(4): 1917-26, 2007 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17902828

RESUMO

This paper describes nonlinear shear wave experiments conducted in soft solids with transient elastography technique. The nonlinear solutions that theoretically account for plane and nonplane shear wave propagation are compared with experimental results. It is observed that the cubic nonlinearity implied in high amplitude transverse waves at f(0)=100 Hz results in the generation of odd harmonics 3f(0), 5f(0). In the case of the nonlinear interaction between two transverse waves at frequencies f(1) and f(2), the resulting harmonics are f(i)+/-2f(j)(i,j=1,2). Experimental data are compared to numerical solutions of the modified Burgers equation, allowing an estimation of the nonlinear parameter relative to shear waves. The definition of this combination of elastic moduli (up to fourth order) can be obtained using an energy development adapted to soft solid. In the more complex situation of nonplane shear waves, the quadratic nonlinearity gives rise to more usual harmonics, at sum and difference frequencies, f(i)+/-f(j). All components of the field have to be taken into account.


Assuntos
Acústica , Dinâmica não Linear , Resistência ao Cisalhamento , Anisotropia , Fenômenos Biomecânicos , Elasticidade , Análise de Elementos Finitos , Humanos , Modelos Lineares , Modelos Teóricos , Imagens de Fantasmas , Reologia , Espectrografia do Som , Resistência à Tração , Viscosidade
7.
Drug Alcohol Depend ; 175: 92-98, 2017 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-28411560

RESUMO

BACKGROUND: Binge drinking (BD) consists of heavy episodic alcohol use. Whereas the World Health Organization (WHO) defines BD as 60g of alcohol or more per occasion, the National Institute on Alcoholism and Alcohol Abuse (NIAAA) conceives BD as drinking 70g (men) or 56g (women) in less than two hours. We compared the subjects delineated by each definition. METHODS: Eight-center cross-sectional study among 11,695 subjects hospitalized in emergency wards. Participants completed the Alcohol Use Disorders Identification Test - Consumption (AUDIT-C), CAGE and Rapid Alcohol Problem Screen 4 (RAPS4-QF) questionnaires. The WHO criteria were investigated using the RAPS4-QF. Independent questions assessed the NIAAA criteria. The main medical admission motive was noted. The characteristics of subjects meeting respectively: 1) the exclusive WHO criteria (BD1); 2) the NIAAA criteria (BD2); and 3) no BD criteria (noBD) were compared using multinomial regression analyses. Binary age- and gender-adjusted regression analyses directly compared BD1 and BD2. Subjects with at least four drinking occasions per week were excluded from the analyses, to withdrawn regular heavy drinking. RESULTS: Compared to BD1, BD2 subjects were more frequently males (OR=1.67 [1.39-2.0]), single (aOR=1.64 [1.36-1.98]) and unemployed (aOR=1.57 [1.27-1.90]). BD2 reported significantly more drinks per occasion, and higher heavy drinking frequencies. Previous alcohol-related remarks from family (aOR=3.00 [2.53-3.56]), ever drinking on waking-up (aOR=2.05 [1.37-2.72]), and admission for psychiatric motive (aOR=2.27 [1.68-3.07]) were more frequent among BD2 subjects. CONCLUSIONS: Compared to WHO criteria, NIAAA criteria for BD delineate subjects with more concerning drinking patterns and alcohol aftermaths.


Assuntos
Consumo de Bebidas Alcoólicas/epidemiologia , Consumo Excessivo de Bebidas Alcoólicas/classificação , Serviço Hospitalar de Emergência/estatística & dados numéricos , Adulto , Consumo de Bebidas Alcoólicas/efeitos adversos , Consumo Excessivo de Bebidas Alcoólicas/diagnóstico , Estudos Transversais , Feminino , França/epidemiologia , Humanos , Masculino , National Institute on Alcohol Abuse and Alcoholism (U.S.)/normas , Valores de Referência , Análise de Regressão , Inquéritos e Questionários , Estados Unidos , Organização Mundial da Saúde
8.
Intern Emerg Med ; 10(5): 607-12, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25808934

RESUMO

Pyelonephritides are frequently encountered diagnosis in Emergency Departments. Urinalyses have a central place in the management of this situation but the usefulness of blood cultures is not clear. We conducted a single-center retrospective study of 24 months to study the microbiological relevance of blood cultures in pyelonephritis. We included patients with blood cultures (BC) and urine cultures (UC) drawn at the same time, if they were not exposed to antibiotics prior to these tests. Of our 264 patients, 39 (15 %) had no bacteriological documentation. There were 83 (31 %) bacteremic patients. Seven patients had contaminated or sterile UC with positive BC. Four patients had positive UC and BC with the latter allowing identification of a pathogen absent from the UC (n = 1) or identifying the main pathogen in three cases. A total of 11 patients theoretically benefited from BC representing 4.2 % of our population. Excluding one patient who was known to be infected with multi-drug resistant bacteria, all empirical antibiotics regimens were effective against the identified pathogens. We did not reveal any significant therapeutic impact of blood cultures in the management of pyelonephritis, when BC and UC are performed before any antimicrobials treatment.


Assuntos
Bacteriemia/diagnóstico , Bacteriemia/microbiologia , Hemocultura , Pielonefrite/microbiologia , Doença Aguda , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pielonefrite/sangue , Pielonefrite/urina , Estudos Retrospectivos , Adulto Jovem
9.
Arch Cardiovasc Dis ; 106(11): 586-92, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24200926

RESUMO

BACKGROUND: Few recent studies have examined the characteristics of ST-segment elevation myocardial infarction (STEMI) among elderly patients managed in emergency departments (EDs). AIMS: To describe the clinical characteristics and management of elderly STEMI patients in EDs. METHODS: This retrospective, multicentre study involved STEMI patients aged ≥ 75 years admitted to four different EDs in the city of Lyon between 2004 and 2008. RESULTS: Among 255 patients, reasons for admission to the ED included chest pain (41.2%), faintness and/or fall (15.7%), dyspnoea (15.7%), digestive symptoms (9.8%), impaired general condition (6.7%) and delirium (5.0%). Compared with those who presented with chest pain, patients admitted for other reasons waited longer before going to the hospital (prehospital delay< 12 hours: 32.0% vs 73.3%; P<0.001), presented with more severe clinical symptoms (Killip score≥III: 28.0% vs 10.5%; P=0.001), waited longer to be examined in the hospital (waiting time > 1 hour: 36.0% vs 11.4%; P<0.001), were less likely to receive reperfusion therapy (40.7% vs 77.1%; P<0.001) and had a higher mortality rate at 1 month (42.7% vs 21.0%; P<0.001). Such atypical symptoms are more common among patients with cognitive impairment and/or communication difficulties. CONCLUSION: Atypical clinical symptoms of STEMI are common and severe among elderly patients in EDs. Thus, rapid provision of an electrocardiogram to all elderly patients admitted to the ED is essential, even in the absence of cardiovascular symptoms.


Assuntos
Serviço Hospitalar de Emergência , Infarto do Miocárdio/diagnóstico , Infarto do Miocárdio/terapia , Admissão do Paciente , Acidentes por Quedas , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Angina Pectoris/etiologia , Delírio/etiologia , Dispneia/etiologia , Eletrocardiografia , Feminino , França , Gastroenteropatias/etiologia , Avaliação Geriátrica , Humanos , Masculino , Infarto do Miocárdio/complicações , Infarto do Miocárdio/mortalidade , Reperfusão Miocárdica , Valor Preditivo dos Testes , Estudos Retrospectivos , Fatores de Risco , Síncope/etiologia , Fatores de Tempo , Tempo para o Tratamento , Resultado do Tratamento
10.
Ultrasonics ; 52(8): 1010-8, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22989947

RESUMO

Mathematical optimization methods based on the topological sensitivity analysis have been used to develop innovative ultrasonic imaging methods. With a single illumination of the medium, they have proved experimentally to yield a lateral resolution comparable to classical multiple-illumination techniques. As these methods are based on the numerical simulations of two wave fields, they require extensive computation. A time-domain finite-difference scheme is usually used for that purpose. This paper presents the development of an experimental imaging method based on the topological sensitivity. The numerical cost is reduced by replacing the numerical simulations by simple mathematical operations between the radiation patterns of the array's transducers and the frequency-domain signals to be emitted. These radiation patterns are preliminary computed once and for all. They were obtained with a finite element model for the anisotropic elastodynamic case and with semi-analytical integrations for the acoustic case. Experimental results are presented for a composite material sample and for a prefractal network immersed in water. A lateral resolution below 2.5 times the wavelength is obtained with a single plane wave illumination. The method is also applied with multiple illuminations, so that objects hidden in complex media can be investigated.

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