Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 54
Filtrar
Mais filtros

Bases de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Phys Rev Lett ; 132(2): 021001, 2024 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-38277596

RESUMO

We show, for the first time, radio measurements of the depth of shower maximum (X_{max}) of air showers induced by cosmic rays that are compared to measurements of the established fluorescence method at the same location. Using measurements at the Pierre Auger Observatory we show full compatibility between our radio and the previously published fluorescence dataset, and between a subset of air showers observed simultaneously with both radio and fluorescence techniques, a measurement setup unique to the Pierre Auger Observatory. Furthermore, we show radio X_{max} resolution as a function of energy and demonstrate the ability to make competitive high-resolution X_{max} measurements with even a sparse radio array. With this, we show that the radio technique is capable of cosmic-ray mass composition studies, both at Auger and at other experiments.

2.
Phys Rev Lett ; 131(1): 015102, 2023 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-37478441

RESUMO

In the dynamic-shell (DS) concept [V. N. Goncharov et al., Novel Hot-Spot Ignition Designs for Inertial Confinement Fusion with Liquid-Deuterium-Tritium Spheres, Phys. Rev. Lett. 125, 065001 (2020).PRLTAO0031-900710.1103/PhysRevLett.125.065001] for laser-driven inertial confinement fusion the deuterium-tritium fuel is initially in the form of a homogeneous liquid inside a wetted-foam spherical shell. This fuel is ignited using a conventional implosion, which is preceded by a initial compression of the fuel followed by its expansion and dynamic formation of a high-density fuel shell with a low-density interior. This Letter reports on a scaled-down, proof-of-principle experiment on the OMEGA laser demonstrating, for the first time, the feasibility of DS formation. A shell is formed by convergent shocks launched by laser pulses at the edge of a plasma sphere, with the plasma itself formed as a result of laser-driven compression and relaxation of a surrogate plastic-foam ball target. Three x-ray diagnostics, namely, 1D spatially resolved self-emission streaked imaging, 2D self-emission framed imaging, and backlighting radiography, have shown good agreement with the predicted evolution of the DS and its stability to low Legendre mode perturbations introduced by laser irradiation and target asymmetries.

3.
Phys Rev Lett ; 130(6): 061001, 2023 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-36827568

RESUMO

Instantons, which are nonperturbative solutions to Yang-Mills equations, provide a signal for the occurrence of quantum tunneling between distinct classes of vacua. They can give rise to decays of particles otherwise forbidden. Using data collected at the Pierre Auger Observatory, we search for signatures of such instanton-induced processes that would be suggestive of super-heavy particles decaying in the Galactic halo. These particles could have been produced during the post-inflationary epoch and match the relic abundance of dark matter inferred today. The nonobservation of the signatures searched for allows us to derive a bound on the reduced coupling constant of gauge interactions in the dark sector: α_{X}≲0.09, for 10^{9}≲M_{X}/GeV<10^{19}. Conversely, we obtain that, for instance, a reduced coupling constant α_{X}=0.09 excludes masses M_{X}≳3×10^{13} GeV. In the context of dark matter production from gravitational interactions alone, we illustrate how these bounds are complementary to those obtained on the Hubble rate at the end of inflation from the nonobservation of tensor modes in the cosmological microwave background.

4.
Phys Rev Lett ; 128(19): 195002, 2022 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-35622051

RESUMO

This Letter presents the first observation on how a strong, 500 kG, externally applied B field increases the mode-two asymmetry in shock-heated inertial fusion implosions. Using a direct-drive implosion with polar illumination and imposed field, we observed that magnetization produces a significant increase in the implosion oblateness (a 2.5× larger P2 amplitude in x-ray self-emission images) compared with reference experiments with identical drive but with no field applied. The implosions produce strongly magnetized electrons (ω_{e}τ_{e}≫1) and ions (ω_{i}τ_{i}>1) that, as shown using simulations, restrict the cross field heat flow necessary for lateral distribution of the laser and shock heating from the implosion pole to the waist, causing the enhanced mode-two shape.

5.
Opt Express ; 29(8): 12240-12251, 2021 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-33984988

RESUMO

In a recent experimental campaign, we used laser-accelerated relativistic hot electrons to ensure heating of thin titanium wire targets up to a warm dense matter (WDM) state [EPL114, 45002 (2016)10.1209/0295-5075/114/45002]. The WDM temperature profiles along several hundred microns of the wire were inferred by using spatially resolved X-ray emission spectroscopy looking at the Ti Kα characteristic lines. A maximum temperature of ∼30 eV was reached. Our study extends this work by discussing the influence of the laser parameters on temperature profiles and the optimisation of WDM wire-based generation. The depth of wire heating may reach several hundreds of microns and it is proven to be strictly dependent on the laser intensity. At the same time, it is quantitatively demonstrated that the maximum WDM temperature doesn't appear to be sensitive to the laser intensity and mainly depends on the deposited laser energy considering ranges of 6×1018-6×1020 W/cm2 and 50-200 J.

6.
Phys Rev Lett ; 126(15): 152002, 2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-33929235

RESUMO

We present the first measurement of the fluctuations in the number of muons in extensive air showers produced by ultrahigh energy cosmic rays. We find that the measured fluctuations are in good agreement with predictions from air shower simulations. This observation provides new insights into the origin of the previously reported deficit of muons in air shower simulations and constrains models of hadronic interactions at ultrahigh energies. Our measurement is compatible with the muon deficit originating from small deviations in the predictions from hadronic interaction models of particle production that accumulate as the showers develop.

7.
Phys Rev Lett ; 126(20): 201102, 2021 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-34110215

RESUMO

The measurement of the energy spectrum of cosmic ray helium nuclei from 70 GeV to 80 TeV using 4.5 years of data recorded by the Dark Matter Particle Explorer (DAMPE) is reported in this work. A hardening of the spectrum is observed at an energy of about 1.3 TeV, similar to previous observations. In addition, a spectral softening at about 34 TeV is revealed for the first time with large statistics and well controlled systematic uncertainties, with an overall significance of 4.3σ. The DAMPE spectral measurements of both cosmic protons and helium nuclei suggest a particle charge dependent softening energy, although with current uncertainties a dependence on the number of nucleons cannot be ruled out.

8.
J Endocrinol Invest ; 44(1): 165-171, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32385852

RESUMO

BACKGROUND: The familial nonmedullary thyroid cancer (FNMTC) is suspected to be a Mendelian condition in up to 3-8% of thyroid cancers. The susceptibility chromosomal loci and genes of 95% of FNMTC cases remain to be characterized. The inheritance of FNMTC appears to be autosomal dominant with incomplete penetrance and variable expressivity. The finding of the causative gene of FNMTC and the identification of patients at risk that need genetic testing were our aim. METHODS: We analyzed by whole-exome sequencing patients and non-affected relatives of five families with at least two family members affected by papillary thyroid cancer, selecting for new or extremely rare variants with predicted pathogenic value. RESULTS: A family showed, in all three affected members, a new loss-of-function variant (frameshift deletion) in BROX gene at 1q41 that was absent from all internal and external databases. In a second family with three affected relatives, we found an additional new BROX variant. The smaller families presented no variants in BROX or in the other causative genes studied. CONCLUSIONS: BROX could be a new causative gene for FNMTC. Variants in BROX may result in the haploinsufficiency of a key gene involved in the morphogenesis of MVBs, in the endosomal sorting of cargo proteins, and in EGFR. Functional studies are needed to support this result. The thorough genomic analysis by NGS in all families with three or more affected members should become a routine approach to obtain a comprehensive genetic view and find confirmative second cases.


Assuntos
Complexos Endossomais de Distribuição Requeridos para Transporte/genética , Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Haploinsuficiência , Câncer Papilífero da Tireoide/patologia , Neoplasias da Glândula Tireoide/patologia , Adulto , Feminino , Testes Genéticos , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Câncer Papilífero da Tireoide/etiologia , Câncer Papilífero da Tireoide/metabolismo , Neoplasias da Glândula Tireoide/etiologia , Neoplasias da Glândula Tireoide/metabolismo
9.
Phys Rev Lett ; 125(12): 121106, 2020 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-33016715

RESUMO

We report a measurement of the energy spectrum of cosmic rays above 2.5×10^{18} eV based on 215 030 events. New results are presented: at about 1.3×10^{19} eV, the spectral index changes from 2.51±0.03(stat)±0.05(syst) to 3.05±0.05(stat)±0.10(syst), evolving to 5.1±0.3(stat)±0.1(syst) beyond 5×10^{19} eV, while no significant dependence of spectral features on the declination is seen in the accessible range. These features of the spectrum can be reproduced in models with energy-dependent mass composition. The energy density in cosmic rays above 5×10^{18} eV is [5.66±0.03(stat)±1.40(syst)]×10^{53} erg Mpc^{-3}.

10.
J Endocrinol Invest ; 43(1): 109-116, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31327128

RESUMO

BACKGROUND: Whether differentiated thyroid cancer (DTC) occurring concomitantly with Graves' disease (GD) is more aggressive and bound to a less favorable outcome is controversial. OBJECTIVE: Aim of this multicenter retrospective study was to compare baseline features and outcome of DTC patients with GD (DTC/GD+) or without GD (DTC/GD-). PATIENTS: Enrolled in this study were 579 patients referred to five endocrine units (Cagliari, Pavia, Pisa, Siena, and Varese) between 2005 and 2014: 193 patients had DTC/GD+ , 386 DTC/GD-. Patients were matched for age, gender and tumor size. They underwent surgery because of malignancy, large goiter size, or relapse of hyperthyroidism in GD. RESULTS: Baseline DTC features (histology, lymph node metastases, extrathyroidal extension) did not differ in the two groups, except for multifocality which was significantly more frequent in DTC/GD+ (27.5% vs. 7.5%, p < 0.0001). At the end of follow-up (median 7.5 years), 86% of DTC/GD+ and 89.6% DTC/GD- patients were free of disease. Patients with persistent or recurrent disease (PRD) had "biochemical disease" in the majority of cases. Microcarcinomas were more frequent in the DTC/GD+ group (60% vs. 37%, p < 0.0001) and had an excellent outcome, with no difference in PRD between groups. However, in carcinomas ≥ 1 cm, PRD was significantly more common in DTC/GD+ (24.4% vs. 11.5%; p = 0.005). In the whole group, univariate and multivariate analyses showed that GD+ , lymph node involvement, extrathyroidal invasion, multifocality and tall cell histotype were associated with a worse outcome. Female gender and microcarcinomas were favorable features. No association was found between baseline TSH-receptor antibody levels and outcome. Graves' orbitopathy (GO) seemed to be associated with a better outcome of DTC, possibly because patients with GO may early undergo surgery for hyperthyroidism. CONCLUSIONS: GD may be associated with a worse outcome of coexisting DTC only if cancer is ≥ 1 cm, whereas clinical outcome of microcarcinomas is not related to the presence/absence of GD.


Assuntos
Adenocarcinoma/mortalidade , Diferenciação Celular , Doença de Graves/complicações , Neoplasias da Glândula Tireoide/mortalidade , Tireoidectomia/mortalidade , Adenocarcinoma/etiologia , Adenocarcinoma/patologia , Adenocarcinoma/cirurgia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida , Neoplasias da Glândula Tireoide/etiologia , Neoplasias da Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/cirurgia
11.
J Endocrinol Invest ; 41(9): 1029-1035, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29470826

RESUMO

PURPOSE: According to American Thyroid Association (ATA) guideline, papillary thyroid cancer (PTC) with minimal extrathyroidal extension (mETE) is classified at "intermediate risk" of persistent/recurrent disease. However, the impact of mETE per se on patients' outcome is not fully understood. The aim of our study was to evaluate the prognostic significance of mETE in patients with PTC not submitted to therapeutic or prophylactic lymph node dissection, according to tumor size and other prognostic factors. PATIENTS AND METHODS: We retrospectively evaluated a total of 514 PTC patients: 127 (24.7%) had mETE (pT3Nx) and 387 (75.3%) had negative margins (pT1-2Nx). At a median follow-up of 9.1 years, patients were divided in two groups: patients with "good outcome" (no evidence of disease) and patients with "poor outcome" (persistent structural disease or recurrent disease or tumor-related death). RESULTS: The rate of patients with "poor outcome" was significantly higher in patients with mETE compared with patients with negative margins (11.8 versus 5.1%; OR 2.4576, 95% CI 1.2178-4.9594, p = 0.01). However, mETE was significantly associated with poor outcome only in patients with tumors larger than 1.5 cm. CONCLUSIONS: mETE is an unfavorable prognostic factor in tumors larger than 1.5 cm, suggesting that, in the absence of other unfavorable characteristics, smaller tumors with mETE should be classified and managed as "low risk" tumors.


Assuntos
Gerenciamento Clínico , Guias de Prática Clínica como Assunto/normas , Câncer Papilífero da Tireoide/diagnóstico , Câncer Papilífero da Tireoide/cirurgia , Tireoidectomia/normas , Instituições Filantrópicas de Saúde/normas , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Feminino , Seguimentos , Humanos , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Câncer Papilífero da Tireoide/classificação , Tireoidectomia/métodos , Adulto Jovem
14.
Nutr Metab Cardiovasc Dis ; 24(9): 1043-9, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24929795

RESUMO

BACKGROUND AND AIMS: In patients with chronic kidney disease (CKD), alterations in gut microbiome are posited to be responsible for gastrointestinal symptoms and generation of p-cresol, a uremic toxin that has been associated with CKD progression and cardiovascular mortality. This pilot study investigated whether Probinul-neutro®, a synbiotic that normalizes intestinal microflora, may lower plasma p-cresol concentrations and reduce gastrointestinal symptoms in non-dialyzed CKD patients. METHODS AND RESULTS: This was a double-blind, randomized placebo-controlled trial. Thirty patients on 3-4 CKD stages were randomized to receive either Probinul neutro® or placebo for 4 weeks. Total plasma p-cresol concentration was assessed at baseline, and 15 and 30 days after treatment start. At the same study times, ease and frequency of defecation, upper and lower abdominal pain, stool shape, borborygmi, and flatus were quantified by subjective assessment questionnaires. Compared to baseline total plasma p-cresol median concentrations on 15th and 30th day were significantly lower in patients receiving Probinul-neutro® (2.31 and 0.78 vs. 3.05 µg/ml, p < 0.05; n = 18); no changes of plasma p-cresol concentrations were recorded in placebo-treated patients. No significant changes in gastrointestinal symptoms were observed during the study both in Probinul-neutro®-treated and placebo-treated patients. CONCLUSION: Probinul-neutro® lowered total plasma p-cresol concentrations but did not ameliorate gastrointestinal symptoms in non-dialyzed CKD patients. Because high plasma concentrations of p-cresol in early phases of CKD are predictive of progression to end-stage renal disease, the results of our study suggest that synbiotics deserve attention as possible tools to delay CKD progression towards end-stage renal disease (ESRD). CLINICALTRIALSGOV IDENTIFIER: NCT02008331.


Assuntos
Cresóis/sangue , Falência Renal Crônica/sangue , Falência Renal Crônica/terapia , Simbióticos , Idoso , Progressão da Doença , Método Duplo-Cego , Feminino , Taxa de Filtração Glomerular , Humanos , Intestinos/microbiologia , Masculino , Pessoa de Meia-Idade , Projetos Piloto
15.
J Endocrinol Invest ; 36(9): 729-33, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23580027

RESUMO

BACKGROUND: Few data exist on the prevalence of female sexual dysfunction (FSD) in thyroid disorders. AIM: We evaluated FSD in women with thyroid diseases and in control age-matched healthy women to investigate the relationship between sexual function and thyroid hormones. METHODS: One hundred and four women with thyroid diseases and 53 controls participated in the study. Eighteen with hyperthyroidism (Group 1), 22 hypothyroidism (Group 2), 45 Hashimoto's thyroiditis (Group 3), 19 nodular goiter (Group 4) underwent thyroid function evaluation and sonography. The Female Sexual Function Index (FSFI) assessed sexual function. RESULTS: The prevalence of FSD was 46.1% in thyroid diseases and 20.7% in controls. Only in Group 4, the prevalence (68.4%) was significantly higher than in controls (p<0.005). The mean total FSFI score was 20.1 ± 7.1 in women with thyroid diseases and 25.6 ± 4.7 in the controls (p<0.001). Compared with controls, there was a significant decrease of desire in Group 2; desire, arousal and lubrication in Group 3; desire, arousal, lubrication, orgasm and satisfaction in Group 4. In thyroid diseases the prevalence of FSD was 53% and 42%, while in the controls was 55% and 20%, in menopausal and pre-menopausal groups, respectively. We found a significant inverse correlation between TSH and FSFI (r=-0.7, p=0.01) in Group 4, which showed the lowest FSFI score (17.8 ± 5.7) and the highest body mass index (28.4 ± 7.1 kg/m(2)). CONCLUSIONS: Women with thyroid diseases present a higher prevalence of FSD than controls. Although our findings suggest a higher impairment of sexual function in Group 4 and a role for TSH in FSD, further researches are needed.


Assuntos
Disfunções Sexuais Fisiológicas/epidemiologia , Disfunções Sexuais Psicogênicas/epidemiologia , Doenças da Glândula Tireoide/epidemiologia , Adulto , Índice de Massa Corporal , Feminino , Bócio Nodular/complicações , Bócio Nodular/epidemiologia , Humanos , Itália/epidemiologia , Menopausa , Pessoa de Meia-Idade , Pré-Menopausa , Prevalência , Disfunções Sexuais Fisiológicas/etiologia , Disfunções Sexuais Psicogênicas/etiologia , Doenças da Glândula Tireoide/complicações , Tireotropina/sangue
16.
G Chir ; 33(11-12): 370-3, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23140918

RESUMO

Multiple endocrine neoplasia syndromes have since been classified as types 1 and 2, each with specific phenotypic patterns. MEN1 is usually associated with pituitary, parathyroid and paraneoplastic neuroendocrine tumours. The hallmark of MEN2 is a very high lifetime risk of developing medullary thyroid carcinoma (MTC) more than 95% in untreated patients. Three clinical subtypesdMEN2A, MEN2B, and familial MTC (FMTC) have been defined based on the risk of pheochromocytoma, hyperparathyroidism, and the presence or absence of characteristic physical features). MEN2 occurs as a result of germline activating missense mutations of the RET (REarranged during Transfection) proto-oncogene. MEN2-associated mutations are almost always located in exons 10, 11, or 13 through 16. Strong genotype-phenotype correlations exist with respect to clinical subtype, age at onset, and aggressiveness of MTC in MEN2. These are used to determine the age at which prophylactic thyroidectomy should occur and whether screening for pheochromocytoma or hyperparathyroidism is necessary. Specific RET mutations can also impact management in patients presenting with apparently sporadic MTC. Therefore, genetic testing should be performed before surgical intervention in all patients diagnosed with MTC. Recently, Pellegata et al. have reported that germline mutations in CDKN1B can predispose to the development of multiple endocrine tumours in both rats and humans and this new MEN syndrome is named MENX and MEN4, respectively. CDKN1B. A recent report showed that in sporadic MTC, CDKN1B V109G polymorphism correlates with a more favorable disease progression than the wild-type allele and might be considered a new promising prognostic marker. New insights on MEN syndrome pathogenesis and related inherited endocrine disorders are of particular interest for an adequate surgical and therapeutic approach.


Assuntos
Inibidor de Quinase Dependente de Ciclina p27/genética , Neoplasia Endócrina Múltipla/genética , Polimorfismo Genético , Inibidores de Proteínas Quinases/metabolismo , Neoplasias das Glândulas Suprarrenais/genética , Alelos , Animais , Biomarcadores/sangue , Progressão da Doença , Éxons , Genótipo , Humanos , Hiperparatireoidismo/genética , Neoplasia Endócrina Múltipla/diagnóstico , Neoplasia Endócrina Múltipla/cirurgia , Neoplasia Endócrina Múltipla Tipo 1/genética , Neoplasia Endócrina Múltipla Tipo 2a/genética , Neoplasia Endócrina Múltipla Tipo 2b/genética , Mutação de Sentido Incorreto , Fenótipo , Feocromocitoma/genética , Proto-Oncogene Mas , Medição de Risco , Fatores de Risco , Síndrome , Neoplasias da Glândula Tireoide/genética , Tireoidectomia , Resultado do Tratamento
17.
Nat Commun ; 12(1): 2679, 2021 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-33976145

RESUMO

Turbulence is ubiquitous in the universe and in fluid dynamics. It influences a wide range of high energy density systems, from inertial confinement fusion to astrophysical-object evolution. Understanding this phenomenon is crucial, however, due to limitations in experimental and numerical methods in plasma systems, a complete description of the turbulent spectrum is still lacking. Here, we present the measurement of a turbulent spectrum down to micron scale in a laser-plasma experiment. We use an experimental platform, which couples a high power optical laser, an x-ray free-electron laser and a lithium fluoride crystal, to study the dynamics of a plasma flow with micrometric resolution (~1µm) over a large field of view (>1 mm2). After the evolution of a Rayleigh-Taylor unstable system, we obtain spectra, which are overall consistent with existing turbulent theory, but present unexpected features. This work paves the way towards a better understanding of numerous systems, as it allows the direct comparison of experimental results, theory and numerical simulations.

18.
Sci Rep ; 10(1): 8100, 2020 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-32393805

RESUMO

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

20.
Sci Rep ; 9(1): 18805, 2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31827132

RESUMO

X-ray phase contrast imaging (XPCI) is more sensitive to density variations than X-ray absorption radiography, which is a crucial advantage when imaging weakly-absorbing, low-Z materials, or steep density gradients in matter under extreme conditions. Here, we describe the application of a polychromatic X-ray laser-plasma source (duration ~0.5 ps, photon energy >1 keV) to the study of a laser-driven shock travelling in plastic material. The XPCI technique allows for a clear identification of the shock front as well as of small-scale features present during the interaction. Quantitative analysis of the compressed object is achieved using a density map reconstructed from the experimental data.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA