Giant intradiploic epidermoid cyst with large osteolytic lesions of the skull: a case report

<p>Abstract</p> <p>Introduction</p> <p>We report a case of tumor growth over a period of four decades, presenting with large multicentric lytic lesions of the skull and a profound mass effect, without neurological deficits. Clinical and radiological features of a patient with a giant intradiploic epidermoid and its impact on the choice of treatments are discussed.</p> <p>Case presentation</p> <p>An 81-year-old Caucasian man, who had first noticed a painless subcutaneous swelling over the left frontal scalp about 40 years ago, presented after a short episode of dizziness, which he experienced after treatment of focal retinal detachment. Computed tomography (CT) and magnetic resonance imaging (MRI) examinations revealed an exceptionally large tumor involving major parts of the skull with extensive destruction of the bone and distinct deformation of the brain. Considering his age and the absence of neurological deficits or pain, the patient refused the option of tumor removal and cranioplasty, yet agreed to a biopsy, which confirmed the suspected diagnosis.</p> <p>Conclusions</p> <p>The course of the disease demonstrates that even patients with large tumors, inducing distinct pathomorphological changes, do not necessarily experience significant impairment of their quality of life without surgery. This is an impressive example of the chance to lead a long and satisfying life without specific medical treatment, avoiding the inherent risks of these procedures. Yet, there is a clear indication for surgery of intradiploic epidermoids in most cases described in the literature.</p

A chemical survey of exoplanets with ARIEL

Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planet’s birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25–7.8 μm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10–100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed – using conservative estimates of mission performance and a full model of all significant noise sources in the measurement – using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL – in line with the stated mission objectives – will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.Peer reviewedFinal Published versio

New ways for a faster alpha spectrometry

Alpha spectrometry is a key technology in many radioanalytical fields for nuclide- and activity determi­nation. Due to the very short range of a radiation in condensed matter, great care must be taken during sample preparation to avoid self-absorption of the a radiation by the measurement sample itself. However, extensive sample preparation and production efforts in conventional a spectrometric analysis are accepted, since it is often the only way to obtain information about the radionuclide(s) in question. In no other discipline is the problem of complex sample preparation as clear as in the investigation of the heaviest known elements, the transactinides (atomic number Z 2": 104), often also referred to as "superheavy el­ements" (SHE). Since these elements are only produced at accelerators with production rates of single atoms per hour or day, all steps from production to the actual chemical experiment to the detection of the characteristic a radiation must be kept as efficient as possible. A key aspect of making SHE studies efficient is the time that elapses from nuclide production until the start of the measurement to identify its nuclear decay. With the aid of automated systems, the chemical properties of the first three SHEs, namely rutherfordium, dubnium and seaborgium, could be studied in liquid phase chemistry experiments. Subsequent SHE could only be studied in the gas phase. In order to be able to investigate the chemical properties of the transseaborgium elements in the aqueous phase, new technologies for a more efficient investigation of the SHE in the aqueous phase were developed within this work. One approach was to combine various individual steps in a previous experimental setup into a single step. Here, the primary focus was on the chemical separation of a sample, followed by sample preparation and measurement with a silicon detector. These steps can be combined if the detector surface is simultaneously a stationary phase with functional groups that selectively accumulate radionuclides from the aqueous solution on the detector surface according to their chemical properties. If this extractive layer is thin enough, the emitted a radiation of the radionuclides can be measured without significant loss of kinetic energy. In the case of accelerator based experiments, the transport of produced radionuclides, the transfer of the SHE into the liquid phase and the separation of by-products of the fusion reaction are additional complex challenges with great optimization potential. To this end, a system was developed to stop recoil nuclei directly in an aqueous phase after they have passed through a physical pre-separator and are then transported along the shortest possible path to the chemical experiment, such as a Si-detector, coated with extractive functional groups. In order to be able to test such systems without access to particle accelerators, a system was also developed to continuously elute from a generator system 211Bi as an a-emitter with a 2 min half-life in a liquid phase. To better classify these new techniques for a fast a-spectrometry, the following sections give a short theoretical overview related to a-emitting radionuclides. In doing so, an overview of the origin of a-emitting radionuclides, the theory of this type of radiation, the currently most common measurement methods and the technical developments in the field of fast analysis of a-emitters will be given.XVI, 138 Seiten ; Illustrationen, Diagramm

On the Influence of Control Type and Strain Rate on the Lifetime of 50CrMo4

In this study, we investigate the influence of control type and strain rate on the lifetime of specimens manufactured from 50CrMo4. This influence is described by a strain rate dependent method that uses cyclic stress strain curves to correct displacement-controlled cyclic test results. The objective of this correction is to eliminate the stress related differences between displacement-controlled cyclic test results and force-controlled cyclic test results. The method is applied to the results of ultrasonic fatigue tests of six different combinations of heat treatment, specimen geometry (notch factor) and atmosphere. In a statistical analysis, the corrected results show an improved agreement with test results obtained on conventional fatigue testing equipment with similar specimens: the standard deviation in combined data sets is significantly reduced (p = 4.1%). We discuss the literature on intrinsic and extrinsic strain rate effects in carbon steels

On the Influence of Control Type and Strain Rate on the Lifetime of 50CrMo4

In this study, we investigate the influence of control type and strain rate on the lifetime of specimens manufactured from 50CrMo4. This influence is described by a strain rate dependent method that uses cyclic stress strain curves to correct displacement-controlled cyclic test results. The objective of this correction is to eliminate the stress related differences between displacement-controlled cyclic test results and force-controlled cyclic test results. The method is applied to the results of ultrasonic fatigue tests of six different combinations of heat treatment, specimen geometry (notch factor) and atmosphere. In a statistical analysis, the corrected results show an improved agreement with test results obtained on conventional fatigue testing equipment with similar specimens: the standard deviation in combined data sets is significantly reduced (p = 4.1%). We discuss the literature on intrinsic and extrinsic strain rate effects in carbon steels

Baeyer-Villiger oxidation tuned to chemoselective conversion of non-activated [18F]fluorobenzaldehydes to [18F]fluorophenols

A reaction pathway via oxidation of [18F]fluorobenzaldehydes offers a very useful tool for the no‐carrier‐added radiosynthesis of [18F]fluorophenols, a structural motive of several potential radiopharmaceuticals. A considerably improved chemoselectivity of the Baeyer‐Villiger oxidation (BVO) towards phenols was achieved, employing 2,2,2‐trifluoroethanol as reaction solvent in combination with Oxone or m‐CPBA as oxidation agent. The studies showed the necessity of H2SO4 addition, which appears to have a dual effect, acting as catalyst and desiccant. For example, 2‐[18F]fluorophenol was obtained with a RCY of 97% under optimised conditions of 80°C and 30‐minute reaction time. The changed performance of the BVO, which is in agreement with known reaction mechanisms via Criegee intermediates, provided the best results with regard to radiochemical yield (RCY) and chemoselectivity, i.e. formation of [18F]fluorophenols rather than [18F]fluorobenzoic acids. Thus, after a long history of the BVO, the new modification now allows an almost specific formation of phenols, even from electron‐deficient benzaldehydes. Further, the applicability of the tuned, chemoselective BVO to the n.c.a. level and to more complex compounds was demonstrated for the products n.c.a. 4‐[18F]fluorophenol (RCY 95%; relating to 4‐[18F]fluorobenzaldehyde) and 4‐[18F]fluoro‐m‐tyramine (RCY 32%; relating to [18F]fluoride), respectively