361 research outputs found

    Inverted and horizontal impacted third molars in an Early Modern skull from Wroclaw, Poland: a case report

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    Background: An impacted tooth is one of the most commonly occurring dental anomalies, although some types of impaction (i.e. inverted angulation) may be considered rare finding. There are many hypotheses regarding impaction aetiology. One of the most popular hypotheses suggested that this condition may result from insufficient space in retromolar space, other: improper angulation of tooth bud, malposition of the tooth germ or hereditary factors, insufficient interproximal attrition, ectopy or dysfunction of genes necessary for proper tooth eruption. This study aims to present the odontological and paleopathological assessment of the impacted molars observed within the skull excavated from an early modern cemetery in Wroclaw.  Materials and methods: The skull used in the study was complete and in a good state of preservation. It belonged to an adult individual whose body was buried at the former Salvator Cemetery (currently Czysty Square). The individual’s dentition was almost completely lost antemortem. Only second molars preserved within the maxillae (bilaterally) and the mandible was almost edentulous as well. The morphometric traits have been taken according to standards established by R. Martin. Macroscopic observations were supported by X-rays and computed tomography imaging.  Results: The age at death was estimated at 20–35 years. Comparison of the metric characteristics of skull with the reference material reveals that it is much smaller than the average female skull from this series. Morphometric indices calculated for both splanchocranium and neurocranium allow defining the skull and jaw as short, which could be an important factor involved in the teeth impaction.  Conclusions: Atypical impaction of the third molars could result from small size of skull and could have significantly deteriorated the quality of life of the individual.

    The response surface methodology for optimization of tyrosinase immobilization onto electrospun polycaprolactone-chitosan fibers for use in bisphenol A removal.

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    Composite polycaprolactone-chitosan material was produced by an electrospinning method and used as a support for immobilization of tyrosinase by mixed ionic interactions and hydrogen bonds formation. The morphology of the fibers and enzyme deposition were confirmed by SEM images. Further, multivariate polynomial regression was used to model the experimental data and to determine optimal conditions for immobilization process, which were found to be pH 7, temperature 25 °C and 16 h process duration. Under these conditions, novel type of biocatalytic system was produced with immobilization yield of 93% and expressed activity of 95%. Furthermore, as prepared system was applied in batch experiments related to biodegradation of bisphenol A under various remediation conditions. It was found that over 80% of the pollutant was removed after 120 min of the process, in the temperature range 15-45 °C and pH 6-9, using solutions at concentration up to 3 mg/L. Experimental data collected proved that the stability and reusability of the tyrosinase were significantly improved upon immobilization: the immobilized biomolecule retained around 90% of its initial activity after 30 days of storage, and was still capable to remove over 80% of bisphenol A even after 10 repeated uses. By contrast, free enzyme was able to remove over 80% of bisphenol A at pH 7-8 and temperature range 15-35 °C, and retained less than 60% of its initial activity after 30 days of storage

    Structural abnormalities of the optic nerve and retina in Huntington’s disease pre-clinical and clinical settings

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    Huntington’s disease (HD) is a fatal neurodegenerative disorder caused by a polyglutamine expansion in the huntingtin protein. HD-related pathological remodelling has been reported in HD mouse models and HD carriers. In this study, we studied structural abnormalities in the optic nerve by employing Spectral Domain Optical Coherence Tomography (SD-OCT) in pre-symptomatic HD carriers of Caucasian origin. Transmission Electron Microscopy (TEM) was used to investigate ultrastructural changes in the optic nerve of the well-established R6/2 mouse model at the symptomatic stage of the disease. We found that pre-symptomatic HD carriers displayed a significant reduction in the retinal nerve fibre layer (RNFL) thickness, including specific quadrants: superior, inferior and temporal, but not nasal. There were no other significant irregularities in the GCC layer, at the macula level and in the optic disc morphology. The ultrastructural analysis of the optic nerve in R6/2 mice revealed a significant thinning of the myelin sheaths, with a lamellar separation of the myelin, and a presence of myelonoid bodies. We also found a significant reduction in the thickness of myelin sheaths in peripheral nerves within the choroids area. Those ultrastructural abnormalities were also observed in HD photoreceptor cells that contained severely damaged membrane disks, with evident vacuolisation and swelling. Moreover, the outer segment of retinal layers showed a progressive disintegration. Our study explored structural changes of the optic nerve in pre- and clinical settings and opens new avenues for the potential development of biomarkers that would be of great interest in HD gene therapies

    Very-high-energy observations of the binaries V 404 Cyg and 4U 0115+634 during giant X-ray outbursts

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    Transient X-ray binaries produce major outbursts in which the X-ray flux can increase over the quiescent level by factors as large as 10710^7. The low-mass X-ray binary V 404 Cyg and the high-mass system 4U 0115+634 underwent such major outbursts in June and October 2015, respectively. We present here observations at energies above hundreds of GeV with the VERITAS observatory taken during some of the brightest X-ray activity ever observed from these systems. No gamma-ray emission has been detected by VERITAS in 2.5 hours of observations of the microquasar V 404 Cyg from 2015, June 20-21. The upper flux limits derived from these observations on the gamma-ray flux above 200 GeV of F <4.4×1012< 4.4\times 10^{-12} cm2^{-2} s1^{-1} correspond to a tiny fraction (about 10610^{-6}) of the Eddington luminosity of the system, in stark contrast to that seen in the X-ray band. No gamma rays have been detected during observations of 4U 0115+634 in the period of major X-ray activity in October 2015. The flux upper limit derived from our observations is F <2.1×1012< 2.1\times 10^{-12} cm2^{-2} s1^{-1} for gamma rays above 300 GeV, setting an upper limit on the ratio of gamma-ray to X-ray luminosity of less than 4%.Comment: Accepted for publication in the Astrophysical Journa

    Dark Matter Constraints from a Joint Analysis of Dwarf Spheroidal Galaxy Observations with VERITAS

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    We present constraints on the annihilation cross section of WIMP dark matter based on the joint statistical analysis of four dwarf galaxies with VERITAS. These results are derived from an optimized photon weighting statistical technique that improves on standard imaging atmospheric Cherenkov telescope (IACT) analyses by utilizing the spectral and spatial properties of individual photon events. We report on the results of \sim230 hours of observations of five dwarf galaxies and the joint statistical analysis of four of the dwarf galaxies. We find no evidence of gamma-ray emission from any individual dwarf nor in the joint analysis. The derived upper limit on the dark matter annihilation cross section from the joint analysis is 1.35×1023cm3s11.35\times 10^{-23} {\mathrm{ cm^3s^{-1}}} at 1 TeV for the bottom quark (bbˉb\bar{b}) final state, 2.85×1024cm3s12.85\times 10^{-24}{\mathrm{ cm^3s^{-1}}} at 1 TeV for the tau lepton (τ+τ\tau^{+}\tau^{-}) final state and 1.32×1025cm3s11.32\times 10^{-25}{\mathrm{ cm^3s^{-1}}} at 1 TeV for the gauge boson (γγ\gamma\gamma) final state.Comment: 14 pages, 9 figures, published in PRD, Ascii tables containing annihilation cross sections limits are available for download as ancillary files with readme.txt file description of limit

    Gamma-ray Observations Under Bright Moonlight with VERITAS

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    Imaging atmospheric Cherenkov telescopes (IACTs) are equipped with sensitive photomultiplier tube (PMT) cameras. Exposure to high levels of background illumination degrades the efficiency of and potentially destroys these photo-detectors over time, so IACTs cannot be operated in the same configuration in the presence of bright moonlight as under dark skies. Since September 2012, observations have been carried out with the VERITAS IACTs under bright moonlight (defined as about three times the night-sky-background (NSB) of a dark extragalactic field, typically occurring when Moon illumination > 35%) in two observing modes, firstly by reducing the voltage applied to the PMTs and, secondly, with the addition of ultra-violet (UV) bandpass filters to the cameras. This has allowed observations at up to about 30 times previous NSB levels (around 80% Moon illumination), resulting in 30% more observing time between the two modes over the course of a year. These additional observations have already allowed for the detection of a flare from the 1ES 1727+502 and for an observing program targeting a measurement of the cosmic-ray positron fraction. We provide details of these new observing modes and their performance relative to the standard VERITAS observations

    Investigating the TeV Morphology of MGRO J1908+06 with VERITAS

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    We report on deep observations of the extended TeV gamma-ray source MGRO J1908+06 made with the VERITAS very high energy (VHE) gamma-ray observatory. Previously, the TeV emission has been attributed to the pulsar wind nebula (PWN) of the Fermi-LAT pulsar PSR J1907+0602. We detect MGRO J1908+06 at a significance level of 14 standard deviations (14 sigma) and measure a photon index of 2.20 +/- 0.10_stat +/- 0.20_sys. The TeV emission is extended, covering the region near PSR J1907+0602 and also extending towards SNR G40.5--0.5. When fitted with a 2-dimensional Gaussian, the intrinsic extension has a standard deviation of sigma_src = 0.44 +/- 0.02 degrees. In contrast to other TeV PWNe of similar age in which the TeV spectrum softens with distance from the pulsar, the TeV spectrum measured near the pulsar location is consistent with that measured at a position near the rim of G40.5--0.5, 0.33 degrees away.Comment: To appear in ApJ, 8 page

    Discovery of Very High Energy Gamma Rays from 1ES 1440+122

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    The BL Lacertae object 1ES 1440+122 was observed in the energy range from 85 GeV to 30 TeV by the VERITAS array of imaging atmospheric Cherenkov telescopes. The observations, taken between 2008 May and 2010 June and totalling 53 hours, resulted in the discovery of γ\gamma-ray emission from the blazar, which has a redshift zz=0.163. 1ES 1440+122 is detected at a statistical significance of 5.5 standard deviations above the background with an integral flux of (2.8±0.7stat±0.8sys\pm0.7_{\mathrm{stat}}\pm0.8_{\mathrm{sys}}) ×\times 1012^{-12} cm2^{-2} s1^{-1} (1.2\% of the Crab Nebula's flux) above 200 GeV. The measured spectrum is described well by a power law from 0.2 TeV to 1.3 TeV with a photon index of 3.1 ±\pm 0.4stat_{\mathrm{stat}} ±\pm 0.2sys_{\mathrm{sys}}. Quasi-simultaneous multi-wavelength data from the Fermi Large Area Telescope (0.3--300 GeV) and the Swift X-ray Telescope (0.2--10 keV) are additionally used to model the properties of the emission region. A synchrotron self-Compton model produces a good representation of the multi-wavelength data. Adding an external-Compton or a hadronic component also adequately describes the data.Comment: 8 pages, 4 figures. Accepted for publication in MNRA

    A Search for Very High-Energy Gamma Rays from the Missing Link Binary Pulsar J1023+0038 with VERITAS

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    The binary millisecond radio pulsar PSR J1023+0038 exhibits many characteristics similar to the gamma-ray binary system PSR B1259--63/LS 2883, making it an ideal candidate for the study of high-energy non-thermal emission. It has been the subject of multi-wavelength campaigns following the disappearance of the pulsed radio emission in 2013 June, which revealed the appearance of an accretion disk around the neutron star. We present the results of very high-energy gamma-ray observations carried out by VERITAS before and after this change of state. Searches for steady and pulsed emission of both data sets yield no significant gamma-ray signal above 100 GeV, and upper limits are given for both a steady and pulsed gamma-ray flux. These upper limits are used to constrain the magnetic field strength in the shock region of the PSR J1023+0038 system. Assuming that very high-energy gamma rays are produced via an inverse-Compton mechanism in the shock region, we constrain the shock magnetic field to be greater than \sim2 G before the disappearance of the radio pulsar and greater than \sim10 G afterwards.Comment: 7 pages, 3 figures, accepted for publication in Ap
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