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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 ; 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.

3.
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.

4.
Doc Ophthalmol ; 143(1): 33-38, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33469852

RESUMO

PURPOSE: To report electroretinographic (ERG) findings in advanced glaucoma treated with a single intravitreal injection of bone marrow-derived mesenchymal stem cells (MSCs). METHODS: Intravitreal injection of autologous MSCs (1 × 106 cells) was performed in 2 eyes from 2 patients with open-angle glaucoma in advanced stage of optic neuropathy (ClinicalTrials.gov, NCT02330978, 01.05.2015): cup/disk ratio worse than 0.9, visual field mean deviation index lower than - 15 dB, visual acuity of light perception, but controlled intraocular pressure. ERG tests were recorded at baseline and week 1, 4 and 48 after injection, using DTL electrodes following the ISCEV standard: After dark adaptation, ERG was elicited using white flashes of 0.01 cd.s/m2 and 3.0 cd.s/m2, followed by 10-min light adaptation (30 cd/m2) and stimuli of 3.0 cd.s/m2 and 30 Hz flicker. RESULTS: Patients did not show improvement on visual acuity or visual field after treatment. At baseline, ERG responses showed typical findings for advanced glaucoma, with a- and b-wave amplitude and latency within normative range, but reduced photopic negative responses. No noteworthy changes were observed on ERG responses for both cases up to 1 week after treatment, but at day 15, one patient showed retinal detachment with proliferative vitreoretinopathy and was removed from the trial. The other patient kept ERG responses stable throughout study period. CONCLUSION: Although no ERG response changes were observed after MSCs injection in one case, the complication observed on the second one, along with the lack of visual function improvement, warrants further studies involving modified MSCs to treat ocular disorders, including glaucoma. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02330978- missed in pdf.


Assuntos
Glaucoma de Ângulo Aberto , Glaucoma , Células-Tronco Mesenquimais , Medula Óssea , Eletrorretinografia , Humanos , Injeções Intravítreas
5.
J Dairy Sci ; 104(1): 179-197, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33131813

RESUMO

Cheeses are able to serve as suitable matrices for supplying probiotics to consumers, enabling appropriate conditions for bacteria to survive gastric transit and reach the gut, where they are assumed to promote beneficial processes. The present study aimed to evaluate the microbiological, immunological, and histological changes in the gut of Salmonella Enteritidis-challenged rats fed goat cheese supplemented with the probiotic strain Lactobacillus rhamnosus EM1107. Thirty male albino Wistar rats were randomly distributed into 5 experimental groups with 6 animals each: negative (NC) and positive (PtC) control groups, control goat cheese (CCh), goat cheese added with L. rhamnosus EM1107 (LrCh), and L. rhamnosus EM1107 only (EM1107). All animals, except NC group were challenged with Salmonella Enteritidis (109 cfu in 1 mL of saline through oral gavage). Microbial composition was assessed with high-throughput 16S rRNA sequencing by means of Illumina MiSeq (Illumina, San Diego, CA). Nuclear factor kappa B (NF-κB) from the animal cecum tissue was determined by real-time PCR and interleukins (TNF-α, IL-1ß, IL-10, and IFN-γ) by means of ELISA. Myeloperoxidase and malondialdehyde levels were determined biochemically. The administration of the L. rhamnosus EM1107 probiotic strain, either as a pure culture or added to a cheese matrix, was able to reduce Salmonella colonization in the intestinal lumen and lessen tissue damage compared with rats from PtC group. In addition, the use of cheese for the probiotic strain delivery (LrCh) was associated with a marked shift in the gut microbiota composition toward the increase of beneficial organisms such as Blautia and Lactobacillus and a reduction in NF-κB expression. These findings support our hypothesis that cheeses might be explored as functional matrices for the efficacious delivery of probiotic strains to consumers.


Assuntos
Queijo/microbiologia , Cabras , Intestinos/imunologia , Intestinos/microbiologia , Lacticaseibacillus rhamnosus/metabolismo , Probióticos , Salmonella enteritidis/imunologia , Animais , Ceco/metabolismo , Ceco/microbiologia , Microbioma Gastrointestinal , Masculino , RNA Ribossômico 16S , Ratos , Ratos Wistar
6.
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}.

7.
Phys Rev Lett ; 118(11): 117401, 2017 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-28368631

RESUMO

We introduce a nondestructive method to determine the position of randomly distributed semiconductor quantum dots (QDs) integrated in a solid photonic structure. By setting the structure in an oscillating motion, we generate a large stress gradient across the QDs plane. We then exploit the fact that the QDs emission frequency is highly sensitive to the local material stress to map the position of QDs deeply embedded in a photonic wire antenna with an accuracy ranging from ±35 nm down to ±1 nm. In the context of fast developing quantum technologies, this technique can be generalized to different photonic nanostructures embedding any stress-sensitive quantum emitters.

8.
Opt Express ; 24(26): 30149-30163, 2016 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-28059292

RESUMO

Qudits, d-level quantum systems, have been shown to provide a better resource for quantum key distribution and other Quantum Information protocols. It is customary to generate photonic qudits using more than one degree of freedom of the same photon. In much the same way, multi-qubit states are generated using only a pair of photons and ingenious ways to manipulate more than one degree of freedom independently. In contrast to such costly implementations in terms of quantum resources, we present the controlled generation of two copies of two-qudit states using four photons and a single degree of freedom, transverse momentum. The degree of entanglement within each pair was inferred by exploiting the availability of two copies of the same state, without the need of a full tomographic reconstruction of the states, and both highly-entangled and separable states were generated. We show theoretically that the set of states obtainable using our setup is very diverse, ranging from maximally entangled states of qudits to separable states.

9.
Phys Rev Lett ; 116(24): 241101, 2016 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-27367377

RESUMO

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8±0.7(stat)±6.7(syst) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principles calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.

10.
Phys Rev Lett ; 117(19): 192001, 2016 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-27858429

RESUMO

Ultrahigh energy cosmic ray air showers probe particle physics at energies beyond the reach of accelerators. Here we introduce a new method to test hadronic interaction models without relying on the absolute energy calibration, and apply it to events with primary energy 6-16 EeV (E_{CM}=110-170 TeV), whose longitudinal development and lateral distribution were simultaneously measured by the Pierre Auger Observatory. The average hadronic shower is 1.33±0.16 (1.61±0.21) times larger than predicted using the leading LHC-tuned models EPOS-LHC (QGSJetII-04), with a corresponding excess of muons.

11.
J Fluoresc ; 25(5): 1389-95, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26245454

RESUMO

We investigate the effects of the excitation power on the photoluminescence spectra of aqueous CdTe/CdS core-shell quantum dots. We have focused our efforts on nanoparticles that are drop-cast on a silicon nitride substrate and dried out. Under such conditions, the emission intensity of these nanocrystals decreases exponentially and the emission center wavelength shifts with the time under laser excitation, displaying a behavior that depends on the excitation power. In the low-power regime a blueshift occurs, which we attribute to photo-oxidation of the quantum dot core. The blueshift can be suppressed by performing the measurements in a nitrogen atmosphere. Under high-power excitation the nanoparticles thermally expand and aggregate, and a transition to a redshift regime is then observed in the photoluminescence spectra. No spectral changes are observed for nanocrystals dispersed in the solvent. Our results show a procedure that can be used to determine the optimal conditions for the use of a given set of colloidal quantum dots as light emitters for photonic crystal optical cavities.


Assuntos
Compostos de Cádmio/química , Luz , Pontos Quânticos/química , Sulfetos/química , Telúrio/química , Água/química , Medições Luminescentes
12.
Oper Dent ; 48(4): 373-390, 2023 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-37352462

RESUMO

OBJECTIVE: To evaluate the adhesion of universal adhesive systems to the dentin of noncarious cervical lesions (NCCLs) by comparing the etch-and-rinse and self-etch strategies through a systematic review and meta-analysis. METHODS: Systematic electronic searches were performed by two independent reviewers into the following databases: PubMed/MEDLINE, Scopus, Web of Science, and Cochrane Library until December of 2021. Only randomized clinical trials were selected, comparing etch-and-rinse and self-etch strategies and using universal adhesive systems in NCCLs. This systematic review was conducted according to the PRISMA guidelines and registered into PROSPERO. RESULTS: After the removal of duplicates, 170 articles were identified. In an initial screening of titles and abstracts, 146 records did not satisfy the inclusion criteria and were, therefore, excluded. Twenty-four studies were eligible for evaluation of the full text, and four were excluded after this step. Finally, 20 randomized clinical trials were included in this systematic review and meta-analysis. CONCLUSION: This systematic review and meta-analysis revealed that applying universal adhesive systems in the etch-and-rinse strategy could lead to better medium-term (>12 to 36 months) retention of NCCL restorations than the self-etch strategy, as well as resulting in lower percentages of marginal discoloration, marginal adaptation, and secondary caries. However, the use of a self-etching strategy can lead to lower postoperative sensitivity.


Assuntos
Cimentos Dentários , Adesivos Dentinários , Humanos , Cimentos Dentários/uso terapêutico , Adesivos Dentinários/uso terapêutico , Cimentos de Resina , Resinas Compostas/uso terapêutico , Colo do Dente , Restauração Dentária Permanente/métodos , Adaptação Marginal Dentária
13.
Phys Rev Lett ; 109(6): 062002, 2012 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-23006259

RESUMO

We report a measurement of the proton-air cross section for particle production at the center-of-mass energy per nucleon of 57 TeV. This is derived from the distribution of the depths of shower maxima observed with the Pierre Auger Observatory: systematic uncertainties are studied in detail. Analyzing the tail of the distribution of the shower maxima, a proton-air cross section of [505±22(stat)(-36)(+28)(syst)] mb is found.

14.
Aust Vet J ; 100(5): 201-204, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35080007

RESUMO

Bovine trichomoniasis, caused by the protozoal parasite Tritrichomonas foetus, is a highly contagious venereal disease characterised by early pregnancy loss, abortion and pyometra. Persistently infected bulls and cows are the primary reservoirs of infection in infected herds. This research investigated the prevalence of T. foetus infection in bulls from properties located across northern Australia and New South Wales. Preputial samples were collected from 606 bulls at slaughter and tested for T. foetus using the VetMAX-Gold Trich Detection Kit (Thermo Fisher Scientific). The apparent prevalence of T. foetus infection varied between regions, with northern regions in the Northern Territory, Queensland and Western Australia showing a prevalence of 15.4%, 13.8% and 11.4%, respectively. There was some evidence of an association between infection and postcode (P = 0.06) and increasing bull age (P = 0.054). This study confirms that T. foetus infection is likely to be present in many beef breeding herds and contributing to lower than expected reproductive performance, particularly across northern Australia.


Assuntos
Doenças dos Bovinos , Infecções Protozoárias em Animais , Tritrichomonas foetus , Matadouros , Aborto Animal/epidemiologia , Animais , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/parasitologia , Feminino , Masculino , Northern Territory , Gravidez , Prevalência , Infecções Protozoárias em Animais/epidemiologia , Infecções Protozoárias em Animais/parasitologia
15.
Opt Express ; 19(4): 3715-29, 2011 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-21369197

RESUMO

Control of spatial quantum correlations in bi-photons is one of the fundamental principles of Quantum Imaging. Up to now, experiments have been restricted to controlling the state of a single bi-photon, by using linear optical elements. In this work we demonstrate experimental control of quantum correlations in a four-photon state comprised of two pairs of photons. Our scheme is based on a high-efficiency parametric downconversion source coupled to a double slit by a variable linear optical setup, in order to obtain spatially encoded qubits. Both entangled and separable pairs have been obtained, by altering experimental parameters. We show how the correlations influence both the interference and diffraction on the double slit.

16.
Phys Rev Lett ; 104(9): 091101, 2010 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-20366976

RESUMO

We describe the measurement of the depth of maximum, X{max}, of the longitudinal development of air showers induced by cosmic rays. Almost 4000 events above 10;{18} eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106{-21}{+35}) g/cm{2}/decade below 10{18.24+/-0.05} eV, and (24+/-3) g/cm{2}/decade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm{2}. The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.

17.
Stem Cell Res Ther ; 9(1): 155, 2018 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-29895334

RESUMO

BACKGROUND: Bone marrow-derived mesenchymal stromal cell (MSC) therapy is a promising treatment for several degenerative ocular diseases; however, no reproducible method of monitoring these cells into the eye has been established. The aim of this study was to describe successful bioluminescence imaging (BLI) to detect viable luciferase-expressing MSC in the eye. METHODS: Human donor MSC in culture were transduced with 50 µl luciferase lentiviral vector (three viral particles/cell) prior to intraocular injection. Twenty-one right eyes of 21 rabbits were evaluated through BLI after receiving 1 × 106 luciferase-expressing MSC intravitreally. Contralateral eyes were injected with vehicle (phosphate-buffered saline (PBS)) and were used as controls. At seven different time points (1 h to 60 days), D-luciferin (40 mg/ml, 300 µl PBS) was injected in subsets of six enucleated eyes for evaluation of radiance decay through BLI analysis. CD90 and CD73 immunofluorescence was studied in selected eyes. RESULTS: Eyes injected with MSC showed high BLI radiance immediately after D-luciferin injection and progressive decay until 60 days. Mean BLI radiance measures from eyes with luciferase-expressing MSC were significantly higher than controls from 8 h to 30 days. At the thirtieth day, positive CD90- and CD73-expressing cells were observed only in the vitreous cavity of eyes injected with MSC. CONCLUSIONS: Viable MSC were identified in the vitreous cavity 1 month after a single injection. Our results confirmed BLI as a useful and reliable method to detect MSC injected into the eye globe.


Assuntos
Medições Luminescentes/métodos , Células-Tronco Mesenquimais/metabolismo , Animais , Humanos , Coelhos
18.
Phys Rev E Stat Nonlin Soft Matter Phys ; 73(3 Pt 1): 032101, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16605577

RESUMO

We investigate the solutions and first passage time distribution for an anomalous diffusion process governed by a generalized non-Markovian Fokker-Planck equation. In our analysis, we also consider the presence of external forces and absorbent (source) terms. In addition, we show that a rich class of diffusive processes, including normal and anomalous ones, can be obtained from the solutions found here.

19.
Eur Phys J C Part Fields ; 75(6): 269, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26120280

RESUMO

Energy-dependent patterns in the arrival directions of cosmic rays are searched for using data of the Pierre Auger Observatory. We investigate local regions around the highest-energy cosmic rays with [Formula: see text] eV by analyzing cosmic rays with energies above [Formula: see text] eV arriving within an angular separation of approximately 15[Formula: see text]. We characterize the energy distributions inside these regions by two independent methods, one searching for angular dependence of energy-energy correlations and one searching for collimation of energy along the local system of principal axes of the energy distribution. No significant patterns are found with this analysis. The comparison of these measurements with astrophysical scenarios can therefore be used to obtain constraints on related model parameters such as strength of cosmic-ray deflection and density of point sources.

20.
Acta Med Port ; 4(1): 9-12, 1991.
Artigo em Português | MEDLINE | ID: mdl-2048426

RESUMO

End-stage chronic renal failure (CRF) is often associated with platelet' disfunction and therefore with impaired hemostasis. Several investigators have reported that rHu Epo, used in the treatment of CRF anaemia, is able to activate a broad spectrum of hematopoietic stem cells, and therefore is able to increase the number of platelets and to induce correction of platelet disfunction. In order to investigate hemostasis changes associated with rHu Epo we studied 8 dialysis patients before and 12 weeks after rHu Epo. RHu Epo did not induce any change in the number of platelets (187710 +/- 52690 vs 204430 +/- 68710; p = NS), but seemed to improve its function (MI% of aggregation with ADP: 46.3 +/- 4.4% vs 49.1 +/- 5.3%; p less than 0.05). There was an improvement in PT (79.0 +/- 3.0% vs 87.5 +/- 8.9%; p less than 0.02) and aPTT (33.3 +/- 5.9" vs 29.3 +/- 2.1"; p less than 0.05) suggesting an improvement in platelet coagulant activities. These preliminary results indicate that rHu Epo does not increase the number of platelets but can induce a correction of platelet disfunction.


Assuntos
Eritropoetina/farmacologia , Ativação Plaquetária/efeitos dos fármacos , Adulto , Testes de Coagulação Sanguínea , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas Recombinantes/farmacologia
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