Histological analysis of the pulp tissue of rats with testosterone deficiency submitted to orthodontic tooth movement induced / Análise histológica do tecido pulpar de ratos com deficiência de testosterona submetidos à movimentação dentária ortodôntica induzida

Considering the increased demand for orthodontic treatments in adult and elderly patients, with possible hormonal changes caused by age, this study carried out a histological analysis of pulp alterations in the molars of testosterone-deficient rats submitted to induced tooth movement (ITM), aiming at a better understanding of the pulp’s biological aspects. Thirty-two Wistar rats were used in four experimental groups, with 8 animals in each: G1 –control group animals, without experimental manipulation; G2 – animals submitted to bilateral orchidectomy; G3 – animals submitted to ITM technique; G4 – castrated animals submitted to ITM. We used a nickel-titanium (NiTi) spring to induce tooth movement, exerting a force of 50cN magnitude on the first upper molar. Seven days after the installation of the ITM device, the animals were euthanized, the jaws were dissected and stored in 10% formaldehyde for 24 hours and processed with routine histological techniques. We evaluated the efficiency of the force and verified tooth movement by measuring the distance between the first and second molars, at the cementoenamel junction level. The groups were histologically evaluated in terms of cellularity pattern, presence of dystrophic and hemodynamic alterations in the dental pulp. The ITM device succeeded in inducing tooth movement in the animals of groups G3 and G4, which differed from each other, with a higher movement rate in the group submitted to castration associated with ITM (G4). In the comparative analysis of groups, the animals’ pulp in groups G1 and G2 (not submitted to ITM) presented histological characteristics typical of the pulp tissue. We found no dystrophic changes such as necrosis, fibrosis, nodules, or calcifications in the pulp of experimental animals that could be attributed to ITM. The animals with orthodontic movement, castrated or not, presented dilated and congested vessels, in addition to hyalinized vessels in the root and coronary pulp. However, we observed no histological changes that could be attributed to testosterone deficiency. Thus, in this experimental model, testosterone deficiency did not cause morphological and degenerative changes in the pulp during tooth movement. The vascular alterations observed in the animals resulted from the orthodontic process

Avaliação dos efeitos da castração associada ao traumatismo dentário na movimentação ortodôntica em ratos / Evaluation of the effects of castration associated with dental trauma on orthodontic movement in rats

O sucesso da movimentação dentária em dentes traumatizados depende da severidade da injuria, sendo a reabsorção radicular uma consequência indesejável e possível de ocorrer antes, durante e após o tratamento ortodôntico. Além disso o status hormonal do paciente tem um grande impacto na conduta do profissional, uma vez que pode influenciar diretamente o sucesso do tratamento ortodôntico. O objetivo deste estudo foi avaliar os efeitos  da movimentação dentária induzida e da deficiência de testosterona sobre a  taxa de movimentação dentária  e estrutura histológica de dentes traumatizados.  Foram utilizados 24 ratos machos Wistar, separados em 4 grupos experimentais (n=6 animais/grupo): MDI: composto por animais que foram submetidos a movimentação dentária induzida (MDI); MDI+CAST: composto por animais que foram submetidos à MDI e orquidectomia bilateral; MDI+TD:  composto por animais que foram submetidos à  MDI e ao traumatismo dentário e MDI+CAST+TD: composto por animais que foram submetidos à MDI, ao TD e a orquidectomia bilateral. Após o período experimental os animais foram eutanasiados, pesados e as maxilas foram retiradas, fixadas em formol a 10%, descalcificadas, cortadas a 5 µm e coradas com hematoxilina e eosina. Ao final do período experimental não foram observadas diferenças estatisticamente significativas no ganho de peso corporal dos animais. A orquidectomia aumentou a taxa de MDI nos animais dos grupos MDI+CAST e MDI+CAST+TD, quando comparado aos demais grupos experimentais, sendo que a maior taxa de movimentação foi observada nos animais do grupo MDI+CAST+TD. Histologicamente, em todos os animais submetidos a movimentação ortodôntica foi observada a presença de células inflamatórias no ligamento periodontal e  osteoclastos ao redor do osso alveolar. Em todos os  grupos foram experimentais foram observadas lacunas de reabsorção radicular. Nos animais controle (MDI) as reabsorções foram leves afetando apenas a estrutura do cemento. Nos grupos MDI+CAST e MDI+TD foram observadas reabsorções radiculares moderadas, com degradação do cemento e dentina. No grupo MDI+CAST+TD foram observada reabsorções radiculares mais severas com extensas lacunas e degradação de dentina radicular.  Conclui-se que a o déficit androgênico, induzido neste estudo pela castração dos animais,  aumentou a taxa de movimentação  dentária ortodôntica e a associação do traumatismo dentário com a orquidectomia potencializou os efeitos da movimentação dentária induzida sobre o processo de reabsorção radicular

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

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 \pm 0.7 (stat) \pm 6.7 (sys) 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-principle 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.Comment: Replaced with published version. Added journal reference and DOI. Supplemental material in the ancillary file

A search for ultra-high-energy photons at the Pierre Auger Observatory exploiting air-shower universality

The Pierre Auger Observatory is the most sensitive detector to primary photons with energies above ∼0.2 EeV. It measures extensive air showers using a hybrid technique that combines a fluorescence detector (FD) with a ground array of particle detectors (SD). The signatures of a photon-induced air shower are a larger atmospheric depth at the shower maximum (X$_{max}$) and a steeper lateral distribution function, along with a lower number of muons with respect to the bulk of hadron-induced background. Using observables measured by the FD and SD, three photon searches in different energy bands are performed. In particular, between threshold energies of 1-10 EeV, a new analysis technique has been developed by combining the FD-based measurement of X$_{max}$ with the SD signal through a parameter related to its muon content, derived from the universality of the air showers. This technique has led to a better photon/hadron separation and, consequently, to a higher search sensitivity, resulting in a tighter upper limit than before. The outcome of this new analysis is presented here, along with previous results in the energy ranges below 1 EeV and above 10 EeV. From the data collected by the Pierre Auger Observatory in about 15 years of operation, the most stringent constraints on the fraction of photons in the cosmic flux are set over almost three decades in energy

Study on multi-ELVES in the Pierre Auger Observatory

Since 2013, the four sites of the Fluorescence Detector (FD) of the Pierre Auger Observatory record ELVES with a dedicated trigger. These UV light emissions are correlated to distant lightning strikes. The length of recorded traces has been increased from 100 μs (2013), to 300 μs (2014-16), to 900 μs (2017-present), to progressively extend the observation of the light emission towards the vertical of the causative lightning and beyond. A large fraction of the observed events shows double ELVES within the time window, and, in some cases, even more complex structures are observed. The nature of the multi-ELVES is not completely understood but may be related to the different types of lightning in which they are originated. For example, it is known that Narrow Bipolar Events can produce double ELVES, and Energetic In-cloud Pulses, occurring between the main negative and upper positive charge layer of clouds, can induce double and even quadruple ELVES in the ionosphere. This report shows the seasonal and daily dependence of the time gap, amplitude ratio, and correlation between the pulse widths of the peaks in a sample of 1000+ multi-ELVES events recorded during the period 2014-20. The events have been compared with data from other satellite and ground-based sensing devices to study the correlation of their properties with lightning observables such as altitude and polarity