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1.
Rev Sci Instrum ; 94(4)2023 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38081262

RESUMO

We describe the first implementation of a Josephson Traveling Wave Parametric Amplifier (JTWPA) in an axion dark matter search. The operation of the JTWPA for a period of about two weeks achieved sensitivity to axion-like particle dark matter with axion-photon couplings above 10-13 Ge V-1 over a narrow range of axion masses centered around 19.84 µeV by tuning the resonant frequency of the cavity over the frequency range of 4796.7-4799.5 MHz. The JTWPA was operated in the insert of the axion dark matter experiment as part of an independent receiver chain that was attached to a 0.56-l cavity. The ability of the JTWPA to deliver high gain over a wide (3 GHz) bandwidth has engendered interest from those aiming to perform broadband axion searches, a longstanding goal in this field.

2.
Phys Rev Lett ; 131(10): 101002, 2023 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-37739367

RESUMO

We report the first result of a direct search for a cosmic axion background (CaB)-a relativistic background of axions that is not dark matter-performed with the axion haloscope, the Axion Dark Matter eXperiment (ADMX). Conventional haloscope analyses search for a signal with a narrow bandwidth, as predicted for dark matter, whereas the CaB will be broad. We introduce a novel analysis strategy, which searches for a CaB induced daily modulation in the power measured by the haloscope. Using this, we repurpose data collected to search for dark matter to set a limit on the axion photon coupling of a CaB originating from dark matter cascade decay via a mediator in the 800-995 MHz frequency range. We find that the present sensitivity is limited by fluctuations in the cavity readout as the instrument scans across dark matter masses. Nevertheless, we suggest that these challenges can be surmounted using superconducting qubits as single photon counters, and allow ADMX to operate as a telescope searching for axions emerging from the decay of dark matter. The daily modulation analysis technique we introduce can be deployed for various broadband rf signals, such as other forms of a CaB or even high-frequency gravitational waves.

3.
Nat Commun ; 13(1): 3688, 2022 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-35760777

RESUMO

The immune-pathology in Crohn's disease is linked to dysregulated CD4+ T cell responses biased towards pathogenic TH17 cells. However, the role of CD8+ T cells able to produce IL-17 (Tc17 cells) remains unclear. Here we characterize the peripheral blood and intestinal tissue of Crohn's disease patients (n = 61) with flow and mass cytometry and reveal a strong increase of Tc17 cells in active disease, mainly due to induction of conventional T cells. Mass cytometry shows that Tc17 cells express a distinct immune signature (CD6high, CD39, CD69, PD-1, CD27low) which was validated in an independent patient cohort. This signature stratifies patients into groups with distinct flare-free survival associated with differential CD6 expression. Targeting of CD6 in vitro reduces IL-17, IFN-γ and TNF production. These results identify a distinct Tc17 cell population in Crohn's disease with proinflammatory features linked to disease activity. The Tc17 signature informs clinical outcomes and may guide personalized treatment decisions.


Assuntos
Doença de Crohn , Interleucina-17 , Linfócitos T CD8-Positivos , Doença de Crohn/metabolismo , Humanos , Interleucina-17/metabolismo , Contagem de Linfócitos , Células Th17
4.
Phys Rev Lett ; 127(26): 261803, 2021 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-35029490

RESUMO

We report the results from a haloscope search for axion dark matter in the 3.3-4.2 µeV mass range. This search excludes the axion-photon coupling predicted by one of the benchmark models of "invisible" axion dark matter, the Kim-Shifman-Vainshtein-Zakharov model. This sensitivity is achieved using a large-volume cavity, a superconducting magnet, an ultra low noise Josephson parametric amplifier, and sub-Kelvin temperatures. The validity of our detection procedure is ensured by injecting and detecting blind synthetic axion signals.

5.
J Xray Sci Technol ; 24(3): 379-88, 2016 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-27257876

RESUMO

Grating based X-ray differential phase contrast imaging (DPCI) allows for high contrast imaging of materials with similar absorption characteristics. In the last years' publications, small animals or parts of the human body like breast, hand, joints or blood vessels have been studied. Larger objects could not be investigated due to the restricted field of view limited by the available grating area. In this paper, we report on a new stitching method to increase the grating area significantly: individual gratings are merged on a carrier substrate. Whereas the grating fabrication process is based on the LIGA technology (X-ray lithography and electroplating) different cutting and joining methods have been evaluated. First imaging results using a 2×2 stitched analyzer grating in a Talbot-Lau interferometer have been generated using a conventional polychromatic X-ray source. The image quality and analysis confirm the high potential of the stitching method to increase the field of view considerably.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Interferometria/métodos , Radiografia/métodos , Animais , Anuros , Desenho de Equipamento , Interferometria/instrumentação , Radiografia/instrumentação
6.
Phys Med Biol ; 59(7): 1557-71, 2014 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-24614413

RESUMO

X-ray phase-contrast imaging has received growing interest in recent years due to its high capability in visualizing soft tissue. Breast imaging became the focus of particular attention as it is considered the most promising candidate for a first clinical application of this contrast modality. In this study, we investigate quantitative breast tissue characterization using grating-based phase-contrast computed tomography (CT) at conventional polychromatic x-ray sources. Different breast specimens have been scanned at a laboratory phase-contrast imaging setup and were correlated to histopathology. Ascertained tumor types include phylloides tumor, fibroadenoma and infiltrating lobular carcinoma. Identified tissue types comprising adipose, fibroglandular and tumor tissue have been analyzed in terms of phase-contrast Hounsfield units and are compared to high-quality, high-resolution data obtained with monochromatic synchrotron radiation, as well as calculated values based on tabulated tissue properties. The results give a good impression of the method's prospects and limitations for potential tumor detection and the associated demands on such a phase-contrast breast CT system. Furthermore, the evaluated quantitative tissue values serve as a reference for simulations and the design of dedicated phantoms for phase-contrast mammography.


Assuntos
Mama/citologia , Mamografia/métodos , Mama/patologia , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/patologia , Humanos , Síncrotrons
7.
Opt Express ; 22(25): 30394-409, 2014 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-25606986

RESUMO

Grating interferometry has been successfully adapted at standard X-ray tubes and is a promising candidate for a broad use of phase-contrast imaging in medical diagnostics or industrial testing. The achievable image quality using this technique is mainly dependent on the interferometer performance with the interferometric visibility as crucial parameter. The presented study deals with experimental investigations of the spectral dependence of the visibility in order to understand the interaction between the single contributing energies. Especially for the choice which type of setup has to be preferred using a polychromatic source, this knowledge is highly relevant. Our results affirm previous findings from theoretical investigations but also show that measurements of the spectral contributions to the visibility are necessary to fully characterize and optimize a grating interferometer and cannot be replaced by only relying on simulated data up to now.

8.
Opt Express ; 21(24): 29101-8, 2013 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-24514461

RESUMO

We present a spectral phase unwrapping approach for grating-based differential phase-contrast data where the unwrapped interferometer phase shift is estimated from energy discriminated measurements using maximum likelihood principles. We demonstrate the method on tomographic data sets of a test specimen taken at different x-ray energies using synchrotron radiation. The proposed unwrapping technique was demonstrated to successfully correct the data set for phase wrapping.


Assuntos
Algoritmos , Intensificação de Imagem Radiográfica/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/métodos , Difração de Raios X/métodos , Funções Verossimilhança , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
9.
Clin Obes ; 3(1-2): 51-5, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25586391

RESUMO

For an increasing number of obese patients, bariatric surgery is considered as the treatment of choice after the failure of conventional strategies. While numerous studies on bariatric surgery have shown substantial health benefits, there is a broad inter-individual variation in the long-term outcome, which is insufficiently understood. Here we show a favourable long-term outcome following multidisciplinary care in a super-super-obese patient. The patient suffered from numerous typically obesity-associated comorbidities and limitations. He underwent multidisciplinary care including two-step bariatric intervention. Endoscopic intragastric balloon positioning was followed by gastric sleeve surgery without Roux-en-Y gastric bypass. His body weight dropped from 260 kg (body mass index [BMI] 79.4 kg m(-2) ) to 85 kg (BMI 25.9 kg m(-2) ) within 16 months and continued to be stable at 90 kg (BMI 27.8 kg m(-2) ) at the end of the follow-up period of 48 months. The loss of excess body weight was associated with the remission of numerous obesity-related comorbidities and with a concomitant pronounced increase in the quality of life and in the socioeconomic status. Eventually, the patient was able to lead a normal life with a decreased risk of long-term complications. We attribute the positive long-term outcome to the following potential determinants: individualized bariatric surgery, multidisciplinary care, the patient's long-term compliance, adequate adherence to the aftercare, physical exercise after surgery, family support, the cooperation of the primary care physician and the financial coverage by the health insurance. Some of these factors remain to be evaluated as predictors of a favourable long-term outcome in prospective trials.

10.
Ther Umsch ; 64(3): 181-5, 2007 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-17323291

RESUMO

Performance food in sports is mainly represented by macronutrients and additional nutritional food components. Performance food is often used in sports as so-called ergogenic aids, which are believed to increase exercise capacity, delay fatigue, or enhance the response to training via different mechanisms. Nevertheless, beneficial effects of only a few of these substances is supported by clear scientific evidence. However, a sound scientific base is lacking for most ergogenic aids, and their intake cannot be recommended. This article focuses on some of the most popular macronutrients and nutritional food components which are consumed with the goal of enhancing performance. Some have been shown to exert a positive impact on exercise capacity under specific conditions, or in connection with an optimal timing of ingestion in context with training. Nevertheless, additional research is required to clarify the role of the different performance foods in increasing exercise capacity before more detailed recommendations are possible.


Assuntos
Dieta/métodos , Suplementos Nutricionais , Alimentos Formulados , Alimentos Fortificados , Fenômenos Fisiológicos da Nutrição , Resistência Física/fisiologia , Esportes/fisiologia , Alimentos Orgânicos , Humanos
11.
Ther Umsch ; 63(8): 509-14, 2006 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-16941394

RESUMO

In industrial nations, over the last five decades conditions concerning nutrition and physical exercise as well as socio-economic circumstances have changed radically. One of the consequences following from this development has been a rapid increase in the prevalence of obesity. Studies have shown that currently 20 percent of the German adult population suffer from obesity. Investigations into the etiology of obesity have to address complex interactions between genetic, socio-economic and psychosocial factors. A year ago, at the University Hospital Tübingen different departments joined to set up the "Plattform Adipositas". Endocrinologists, obesity surgeons, professionals in sports medicine and psychosomatic medicine as well as dieticians are collaborating to develop scientifically based therapy programs and treatment pathways for obese patients. The following article gives an account of this exemplary interdisciplinary cooperation.


Assuntos
Obesidade/diagnóstico , Obesidade/terapia , Equipe de Assistência ao Paciente/tendências , Alemanha , Humanos , Guias de Prática Clínica como Assunto , Padrões de Prática Médica/tendências
12.
Int J Sports Med ; 25(1): 20-6, 2004 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-14750008

RESUMO

Hypertrophic cardiomyopathy (HCM) is one of the primary causes of sudden cardiac death in athletes < 35 years of age. The highest risk of sudden cardiac death is associated with syncope, early age, extreme ventricular hypertrophy, ventricular tachycardia, and a family history of sudden death. The relative risk in competitive sports is unknown. Usually, sports eligibility is rejected. However, some athletes with HCM tolerate extreme athletic lifestyles without complications. Sports-related aspects of diagnosis, therapy, and sports eligibility are presented, and discussed. Two case reports are presented: a 20-year-old professional soccer player and a 66-year-old long-distance runner. Athletes with HCM should not participate in most competitive sports with the possible exception of those of low dynamic and low static intensity. Participation in low to moderate athletic activities may be allowed in selected patients without risk factors and > 35 years of age.


Assuntos
Cardiomiopatia Hipertrófica/diagnóstico , Cardiomiopatia Hipertrófica/terapia , Medicina Esportiva/métodos , Cardiomiopatia Hipertrófica/fisiopatologia , Morte Súbita Cardíaca/etiologia , Morte Súbita Cardíaca/prevenção & controle , Diagnóstico por Imagem , Teste de Esforço , Humanos , Guias de Prática Clínica como Assunto
13.
Herz ; 26(7): 447-53, 2001 Nov.
Artigo em Alemão | MEDLINE | ID: mdl-11765477

RESUMO

BACKGROUND: Training increases work capacity and concomitantly quality of life, and also, according to new data, the life expectancy of patients with coronary heart disease and heart failure. At the same time, the importance of adequate training intensity increases aiming at low complications and high efficacy. ASSESSMENT OF EXERCISE CAPACITY: The objective of the present work is to define objective training guidance parameters in cardiac rehabilitation. Maximal exercise capacity must be distinguished from the performance without symptoms of oxygen deficit. The latter used to be early surpassed in untreated stabile angina pectoris. Within the last decade optimized therapy often yields a cardiac performance limit above the anaerobic threshold derived from lactate measurements. The concepts of aerobic and anaerobic thresholds derived from the lactate performance curve are introduced and modified leaving the 4 mmol/l lactate threshold concept to meet the criteria for performance capacity and breaking point in cardiac patients. The relationship to threshold concepts derived from spirometric data is mentioned as well as from stress hormones. The heart rate at the anaerobic threshold measured at treadmill ergometry systematically lies above the one from bicycle ergometry. Lactate increases faster with advancing age and the anaerobic threshold is earlier reached and progressively so because of the reduced muscle mass and reduced endurance capacity of people of the industrialized countries. IMPORTANCE: The determination of the anaerobic threshold as an objective criteria independent of motivation leads to training control, as shown by an example. Ineffective training above the threshold giving rise to catecholamines can be avoided by lactate performance diagnostic. Additionally, the success of rehabilitation measures can objectively be quantified and documented much better from the threshold work capacity than from maximal exercise tolerance. Preliminary reports indicate the importance of lactate diagnostics for rehabilitation guidance in heart failure.


Assuntos
Doença das Coronárias/reabilitação , Exercício Físico/fisiologia , Insuficiência Cardíaca/reabilitação , Ácido Láctico/sangue , Adulto , Fatores Etários , Idoso , Limiar Anaeróbio/fisiologia , Doença das Coronárias/fisiopatologia , Insuficiência Cardíaca/fisiopatologia , Humanos , Pessoa de Meia-Idade , Músculo Esquelético/fisiopatologia , Resistência Física/fisiologia , Aptidão Física/fisiologia
14.
Int J Sports Med ; 17 Suppl 3: S132-9, 1996 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9119533

RESUMO

One- and two-dimensional echocardiography permits assessment of left ventricular size and muscle mass, whereas the validity and reliability differ. It is comparable to other methods, such as angiography, scintigraphy and magnetic resonance imaging, but has the advantage of being noninvasive and of lower cost. It therefore appears particularly well-suited for applications in sports medicine. However, changes of 10%-20%, depending on the parameter, are necessary in individual cases to permit assumption of a proven change. A further methodical improvement, especially in respect to reliability but also to validity may be expected in the future from three-dimensional, computer-supported examination techniques. Enlargement of the heart due to endurance sports is harmonic and affects all four cardiac chambers. Limits to the increase in left ventricular volume and muscle mass can be recognized in relation to body weight. They usually do not exceed 70% of the baseline value or the value obtained for untrained persons. Power training, even in extreme forms, results in no or only minimal dimensional changes.


Assuntos
Volume Cardíaco , Ecocardiografia , Coração/anatomia & histologia , Adaptação Fisiológica , Angiografia , Peso Corporal , Custos e Análise de Custo , Ecocardiografia/economia , Ecocardiografia/métodos , Ecocardiografia/estatística & dados numéricos , Coração/diagnóstico por imagem , Coração/fisiologia , Ventrículos do Coração/anatomia & histologia , Ventrículos do Coração/diagnóstico por imagem , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Resistência Física , Cintilografia , Reprodutibilidade dos Testes , Esportes/educação , Medicina Esportiva , Função Ventricular
15.
Int J Sports Med ; 15(5): 273-7, 1994 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-7960323

RESUMO

Hypertrophic non-obstructive cardiomyopathy (HNCM) is one of the most frequent causes of sudden cardiac death in young athletes. Since the clinical findings in HNCM patients may be inconspicuous and the ECG changes found in endurance athletes may be similar to those of HNCM patients, echocardiography, as a non-invasive procedure, seems to take on an important role in differential diagnostics. To prove this hypothesis, conventional echocardiographic parameters were compared in three groups with confirmed diagnosis: Group I: HNCM (n = 9) without sports activity; Group II: HNCM (n = 9) with regular, intensive endurance training (3-5 hours/week). The diagnosis was invasively confirmed in both groups. Group III: healthy subjects (n = 9) with physiological hypertrophy and regular endurance training (3-6 hours/week). In the presence of HNCM, endurance sports activity appears to offset the reduction in the left ventricle and enlargement of the left atrium. The wall thickness of the septum and posterior wall do not differ in the two HNCM groups, but show a significant difference to the healthy athletes. The enddiastolic diameter, the absolute septum and posterior wall thickness and the ratio of septum+posterior wall/enddiastolic diameter can be taken as the most important differential diagnostic criterium in physiological hypertrophy, but not the ratio between septum/posterior wall. It is concluded that conventional echocardiographic examination can be considered a valuable non-invasive method for differentiating HNCM from athlete's heart, even in patients with HNCM who participate in endurance sports. However, a reliable diagnosis may not be possible in individual cases.


Assuntos
Cardiomegalia/diagnóstico por imagem , Cardiomiopatia Hipertrófica/diagnóstico por imagem , Resistência Física/fisiologia , Esportes/fisiologia , Adolescente , Adulto , Cardiomegalia/fisiopatologia , Cardiomiopatia Hipertrófica/fisiopatologia , Ecocardiografia , Humanos , Masculino , Pessoa de Meia-Idade
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