455 research outputs found
Neurosurgical Treatment of Breast Cancer Metastases to the Neurocranium
Breast cancer metastases to the neurocranium might involve the bone, the dura, or the brain parenchyma. The latter location is the far most common. The annual incidence of brain metastases in patients with breast cancer is in the range of 4–11 per 100.000 persons per year. Symptoms and findings mainly result from the location of the lesion. The diagnostic method of choice is magnetic resonance imaging before and after administration of contrast material. Breast cancer brain metastases present as solid, cystic, or partially cystic lesions with marked contrast enhancement and perilesional edema. The therapeutic option of choice is microsurgical resection whenever possible. Adjuvant treatment includes radiotherapy, radiosurgery, and/or chemotherapy
Ewing Sarcoma of the Posterior Fossa in an Adolescent Girl
Medulloblastoma, astrocytoma, and ependymoma represent the most common infratentorial tumors in childhood, while Ewing sarcomas in that localization are extremely rare. A large left infratentorial space-occupying lesion was diagnosed in a 12-year-old girl with signs of increased intracranial pressure. Following total tumor resection, histological and molecular examination revealed Ewing sarcoma with rearranged EWSR-1 gene. The patient achieved complete remission following adjuvant chemotherapy and radiotherapy according to Euro-EWING 2008 treatment protocol. Intracranial Ewing sarcoma, although rare, should be an important differential diagnosis of intracranial tumors in childhood which requires aggressive multimodal treatment
Papillary Ependymoma WHO Grade II of the Aqueduct Treated by Endoscopic Tumor Resection
Papillary ependymoma is a rare tumor that may be located along the ventricular walls or within the spinal cord. We report the case of a 54-year-old patient with a papillary ependymoma WHO grade II arising at the entrance of the aqueduct. The tumor caused hydrocephalus. The tumor was completely removed via a right-sided endoscopic approach with restoration of the aqueduct. The free cerebrospinal fluid passage through the aqueduct was not only visualized by endoscopy but also controlled by intraoperative high-field magnetic resonance imaging. Therefore, an additional endoscopic third ventriculostomy was unneccessary
Acute Hydrocephalus due to Secondary Leptomeningeal Dissemination of an Anaplastic Oligodendroglioma
Secondary leptomeningeal dissemination of oligodendroglioma is very rare. We report the case of a 38-year-old Caucasian male who presented with acute hydrocephalus. 8 months before, the patient had undergone craniotomy for right frontal anaplastic oligodendroglioma, WHO grade III. By that time, there was no evidence of tumor dissemination. MRI now ruled out local tumor progression but revealed meningeal contrast enhancement along the medulla, the myelon, and the cauda equina. Repeated lumbar puncture revealed increased cerebro-spinal fluid (CSF) pressure and protein content. Malignant cells were not detectable. Surgical treatment consisted in (1) placement of an ommaya reservoir for daily CSF puncture, (2) Spinal dural biopsy confirming leptomeningeal oligodendroglioma metastasis, and (3) ventriculo-peritoneal shunt placement after CSF protein has decreased to 1500–2000 mg/l
Gain in Three-Dimensional Metamaterials utilizing Semiconductor Quantum Structures
We demonstrate gain in a three-dimensional metal/semiconductor metamaterial
by the integration of optically active semiconductor quantum structures. The
rolling-up of a metallic structure on top of strained semiconductor layers
containing a quantum well allows us to achieve a three-dimensional superlattice
consisting of alternating layers of lossy metallic and amplifying gain
material. We show that the transmission through the superlattice can be
enhanced by exciting the quantum well optically under both pulsed or continuous
wave excitation. This points out that our structures can be used as a starting
point for arbitrary three-dimensional metamaterials including gain
Shifting new media: from content to consultancy, from heterarchy to hierarchy
This is a detailed case history of one of London’s iconic new media companies, AMX Studios. Some of the changes in this firm, we assume, are not untypical for other firms in this sector. Particularly we want to draw attention to two transformations. The first change in AMX and in London’s new media industry more generally refers to the field of industrial relations. What can be observed is a shift from a rather heterarchical towards a more hierarchical organized new media industry, a shift from short-term project networks to long-term client dependency. The second change refers to new media products and services. We want to argue for a shift from cool content production towards consultancy and interactive communications solutions
Coming down from the trees: is terrestrial activity in Bornean orangutans natural or disturbance driven?
The orangutan is the world's largest arboreal mammal, and images of the red ape moving through the tropical forest canopy symbolise its typical arboreal behaviour. Records of terrestrial behaviour are scarce and often associated with habitat disturbance. We conducted a large-scale species-level analysis of ground-based camera-trapping data to evaluate the extent to which Bornean orangutans Pongo pygmaeus come down from the trees to travel terrestrially, and whether they are indeed forced to the ground primarily by anthropogenic forest disturbances. Although the degree of forest disturbance and canopy gap size influenced terrestriality, orangutans were recorded on the ground as frequently in heavily degraded habitats as in primary forests. Furthermore, all age-sex classes were recorded on the ground (flanged males more often). This suggests that terrestrial locomotion is part of the Bornean orangutan's natural behavioural repertoire to a much greater extent than previously thought, and is only modified by habitat disturbance. The capacity of orangutans to come down from the trees may increase their ability to cope with at least smaller-scale forest fragmentation, and to cross moderately open spaces in mosaic landscapes, although the extent of this versatility remains to be investigated
The RESOLVE and ECO Gas in Galaxy Groups Initiative: The Group Finder and the Group HI–Halo Mass Relation
We present a four-step group-finding algorithm for the Gas in Galaxy Groups (G3) initiative, a spin-off of the z ∼ 0 REsolved Spectroscopy Of a Local VolumE (RESOLVE) and Environmental COntext (ECO) surveys. In preparation for future comparisons to intermediate redshift (e.g., the LADUMA survey), we design the group finder to adapt to incomplete, shallow, or nonuniform data. We use mock catalogs to optimize the group finder’s performance. Compared to friends-of-friends (with false-pair splitting), the G3 algorithm offers improved completeness and halo-mass recovery with minimal loss of purity. Combining it with the volume-limited H I census data for RESOLVE and ECO, we examine the H I content of galaxy groups as a function of group halo mass. Group-integrated H I mass M rises monotonically over halo masses M ∼ 10–10 M, pivoting in slope at M ∼ 10M, the gas-richness threshold scale. We present the first measurement of the scatter in this relation, which has a median of ∼0.3 dex and is asymmetric toward lower M I,grp. We discuss interesting tensions with theoretical predictions and prior measurements of the M–M relation. In an appendix, we release RESOLVE DR4 and ECO DR3, including updates to survey redshifts, photometry, and group catalogs, as well as a major expansion of the ECO H I inventory with value-added data products. © 2023. The Author(s). Published by the American Astronomical SocietyWe are grateful to the anonymous referee, whose feedback has improved the quality of this work. We also thank Adrienne Erickcek, Andrew Mann, Mugdha Polimera, Matthew Bershady, Joshua Oppor, Jeremy Darling, Hayley Roberts, and Amir Kazemi-Moridani for valuable feedback at varying stages of the project. Z.L.H., S.J.K., and E.R.C. acknowledge support for this research from National Science Foundation (NSF) grant AST-1814486. Z.L.H. and D.S.C. are also supported through a North Carolina Space Grant Graduate Research Fellowship. S.J.K. and D.S.C. acknowledge support from NSF grant AST-2007351. A.J.B. acknowledges support from NSF grant AST-1814421. K.M.H. acknowledges financial support from the State Agency for Research of the Spanish Ministry of Science, Innovation and Universities through the "Center of Excellence Severo Ocho" awarded to the Instituto de Astrofisica de Andalucia (SEV-2017-0709), via participation in SKA-SPAIN, funded by the Ministry of Science and Innovation (MCIN), and financial support from grant RTI2018-096228-B-C31 (MCIU/AEI/FEDER,UE)
Periodic and Quasiperiodic Motion of an Elongated Microswimmer in Poiseuille Flow
We study the dynamics of a prolate spheroidal microswimmer in Poiseuille flow
for different flow geometries. When moving between two parallel plates or in a
cylindrical microchannel, the swimmer performs either periodic swinging or
periodic tumbling motion. Although the trajectories of spherical and elongated
swimmers are qualitatively similar, the swinging and tumbling frequency
strongly depends on the aspect ratio of the swimmer. In channels with reduced
symmetry the swimmers perform quasiperiodic motion which we demonstrate
explicitely for swimming in a channel with elliptical cross section
Major Outbreak of Hepatitis A Associated with Orange Juice among Tourists, Egypt, 2004
In 2004, a major outbreak of hepatitis A among tourists returning from Egypt involved 351 case-patients from 9 European countries who were infected with a single strain (genotype 1b). The case-control study identified orange juice as the most likely infection vehicle. Vaccination against hepatitis A virus is strongly recommended before travel to disease-endemic areas
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