1,415 research outputs found

    Chelifer longimanus Kollar, 1848: a nomen nudum corresponding to Neobisium spelaeum (Schiödte, 1847) (Pseudoscorpiones: Chelonethi: Neobisiidae)

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    The manuscript name Chelifer longimanus Kollar, 1848, most often cited as Obisium longimanum Kollar, was first introduced in a note by Kollar (1848) that has been overlooked in the taxonomic literature on pseudoscorpions. No description or indication has been associated with this name, which is therefore a nomen nudum. It corresponds to the valid pseudoscorpion species Neobisium spelaeum (Schiödte, 1847), having been found at one of the type localities of the latter (Postojna Cave, Slovenia). Two specimens originally identified as O. longimanum (probably by V. Kollar) are present in the collections of the Naturhistorisches Museum Wien

    Direct Electrical Arc Ignition of Hybrid Rocket Motors

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    Hybrid rockets motors provide distinct safety advantages when compared to traditional liquid or solid propellant systems, due to the inherent stability and relative inertness of the propellants prior to established combustion. As a result of this inherent propellant stability, hybrid motors have historically proven difficult to ignite. State of the art hybrid igniter designs continue to require solid or liquid reactants distinct from the main propellants. These ignition methods however, reintroduce to the hybrid propulsion system the safety and complexity disadvantages associated with traditional liquid or solid propellants. The results of this study demonstrate the feasibility of a novel direct electrostatic arc ignition method for hybrid motors. A series of small prototype stand-alone thrusters demonstrating this technology were successfully designed and tested using Acrylonitrile Butadiene Styrene (ABS) plastic and Gaseous Oxygen (GOX) as propellants. Measurements of input voltage and current demonstrated that arc-ignition will occur using as little as 10 watts peak power and less than 5 joules total energy. The motor developed for the stand-alone small thruster was adapted as a gas generator to ignite a medium-scale hybrid rocket motor using nitrous oxide /and HTPB as propellants. Multiple consecutive ignitions were performed. A large data set as well as a collection of development \u27lessons learned\u27 were compiled to guide future development and research. Since the completion of this original groundwork research, the concept has been developed into a reliable, operational igniter system for a 75mm hybrid motor using both gaseous oxygen and liquid nitrous oxide as oxidizers. A development map of the direct spark ignition concept is presented showing the ow of key lessons learned between this original work and later follow on development

    A Mound Is In The Graveyard

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    https://digitalcommons.library.umaine.edu/mmb-vp/5113/thumbnail.jp

    Imaging of Skeletal Metastases in Myxoid Liposarcoma

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    Unlike other soft tissue sarcomas, myxoid/round cell liposarcoma (MRCL) has a tendency to spread to extrapulmonary sites but bone metastases are thought to be uncommon. In case reports, negative bone scintigraphy has been noted in patients with myxoid/round cell liposarcoma and bone metastases but the prevalence and optimal method of diagnosis of bone metastases in this common subtype of liposarcoma are unclear. In an attempt to answer these questions, data were obtained from a prospective database of patients with sarcoma, including MRCL, and the diagnostic imaging used was examined. A variety of imaging tools were used including plain X-rays, bone scintigraphy, computed tomography (CT), and magnetic resonance imaging (MRI). Eight patients (4.3%) developed skeletal metastases all of which were positive on MRI. Bone scintigraphy was negative in two out of four cases, CT was negative in six out of seven, and X-rays were negative in four. Radiography and CT measure mainly cortical bone involvement, whereas MRI examines bone marrow. When investigating patients with MRCL for bone pain, negative X-rays and bone scans do not rule out bone metastases. In our experience, MRI provides the most sensitive technique for the diagnosis of bone metastases in MRCL

    The value of computed tomographic (CT) scan surveillance in the detection and management of brain metastases in patients with small cell lung cancer.

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    One hundred and twenty-seven consecutive patients presenting with small cell lung cancer were entered into a whole-brain CT scan surveillance study, starting at presentation and repeating at 3-monthly intervals for 2 years as an alternative to prophylactic cranial irradiation (PCI). The aim of the study was to detect CNS metastases at an early asymptomatic stage in the hope that prompt CNS radiotherapy could achieve long-term control; at the same time unnecessary PCI with its potential long-term morbidity could be avoided. CNS metastases were found in 56 patients (44%) including 16 (13%) at diagnosis and 40 at a median of 4 months (range 1-27 months) after completing chemotherapy. No patient developed CNS disease while on chemotherapy. Thirty-six patients were asymptomatic at diagnosis (group A) but 20 developed clinical CNS relapse between scans (group B) (interval relapse). Despite prompt radiotherapy 56% of patients in group A and 60% of patients in group B died with active CNS disease. Likewise, there was no survival difference between patients in group A, group B or those who never developed CNS disease. Regular 3-month CT scan surveillance is therefore not an effective substitute for PCI

    UK guidelines for the management of soft tissue sarcomas

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    Soft tissue sarcomas (STS) are rare tumours arising in mesenchymal tissues, and can occur almost anywhere in the body. Their rarity, and the heterogeneity of subtype and location means that developing evidence-based guidelines is complicated by the limitations of the data available. However, this makes it more important that STS are managed by teams, expert in such cases, to ensure consistent and optimal treatment, as well as recruitment to clinical trials, and the ongoing accumulation of further data and knowledge. The development of appropriate guidance, by an experienced panel referring to the evidence available, is therefore a useful foundation on which to build progress in the field. These guidelines are an update of the previous version published in 2010 (Grimer et al. in Sarcoma 2010:506182, 2010). The original guidelines were drawn up following a consensus meeting of UK sarcoma specialists convened under the auspices of the British Sarcoma Group (BSG) and were intended to provide a framework for the multidisciplinary care of patients with soft tissue sarcomas. This current version has been updated and amended with reference to other European and US guidance. There are specific recommendations for the management of selected subtypes of disease including retroperitoneal and uterine sarcomas, as well as aggressive fibromatosis (desmoid tumours) and other borderline tumours commonly managed by sarcoma services. An important aim in sarcoma management is early diagnosis and prompt referral. In the UK, any patient with a suspected soft tissue sarcoma should be referred to one of the specialist regional soft tissues sarcoma services, to be managed by a specialist sarcoma multidisciplinary team. Once the diagnosis has been confirmed using appropriate imaging, plus a biopsy, the main modality of management is usually surgical excision performed by a specialist surgeon. In tumours at higher risk of recurrence or metastasis pre- or post-operative radiotherapy should be considered. Systemic anti-cancer therapy (SACT) may be utilized in some cases where the histological subtype is considered more sensitive to systemic treatment. Regular follow-up is recommended to assess local control, development of metastatic disease, and any late-effects of treatment. For local recurrence, and more rarely in selected cases of metastatic disease, surgical resection would be considered. Treatment for metastases may include radiotherapy, or systemic therapy guided by the sarcoma subtype. In some cases, symptom control and palliative care support alone will be appropriate

    Ground-Based Thermography of Fluvial Systems at Low and High Discharge Reveals Potential Complex Thermal Heterogeneity Driven by Flow Variation and Bioroughness

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    Temperature is a primary physical and biogeochemical variable in aquatic systems. Field-based measurement of temperature at discrete sampling points has revealed temperature variability in fluvial systems, but traditional techniques do not readily allow for synoptic sampling schemes that can address temperature-related questions with broad, yet detailed, coverage. We present results of thermal infrared imaging at different stream discharge (base flow and peak flood) conditions using a handheld IR camera. Remotely sensed temperatures compare well with those measured with a digital thermometer. The thermal images show that periphyton, wood, and sandbars induce significant thermal heterogeneity during low stages. Moreover, the images indicate temperature variability within the periphyton community and within the partially submerged bars. The thermal heterogeneity was diminished during flood inundation, when the areas of more slowly moving water to the side of the stream differed in their temperature. The results have consequences for thermally sensitive hydroecological processes and implications for models of those processes, especially those that assume an effective stream temperature
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