early radiation
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Author(s):  
Apolline ALFSEN ◽  
Mark BOSSELAERS ◽  
Olivier LAMBERT

In spite of a continuously expanding physeteroid fossil record, our understanding of the origin and early radiation of the two modern sperm whale families Kogiidae Gill, 1871 (including the pygmy and dwarf sperm whales, Kogia spp.) and Physeteridae Gray, 1821 (including the great sperm whale, Physeter Linnaeus, 1758) remains limited, especially due to the poorly resolved phylogenetic relationships of a number of extinct species. Among those, based on fragmentary cranial material from the late early to middle Miocene of Antwerp (Belgium, North Sea basin), the small-sized Thalassocetus antwerpiensis Abel, 1905 has been recognized for some time as the earliest branching kogiid. The discovery of a new diminutive physeteroid cranium from the late Miocene (Tortonian) of Antwerp leads to the description and comparison of a close relative of T. antwerpiensis. Thanks to the relatively young ontogenetic stage of this new specimen, the highly modified plate-like bones making the floor of its supracranial basin could be individually removed, a fact that greatly helped deciphering their identity and geometry. Close morphological similarities with T. antwerpiensis allow for the reassessment of several facial structures in the latter; the most important reinterpretation is the one of a crest-like structure, previously identified as a sagittal facial crest, typical for kogiids, and here revised as the left posterolateral wall of the supracranial basin, comprised of the left nasal (lost in kogiids for which the postnarial region is known) and the left maxilla. Implemented in a phylogenetic analysis, the new anatomical interpretations result in the new Belgian specimen and T. antwerpiensis being recovered as sister-groups in the family Physeteridae. Consequently, the geologically oldest kogiids are now dated from the Tortonian, further extending the ghost lineage separating these early late Miocene kogiid records from the estimated latest Oligocene to earliest Miocene divergence of kogiids and physeterids.


2021 ◽  
pp. jnumed.121.262610
Author(s):  
Giulia Tamborino ◽  
Yann Perrot ◽  
Marijke De Saint-Hubert ◽  
Lara Struelens ◽  
Julie Nonnekens ◽  
...  

2021 ◽  
Vol 28 (5) ◽  
pp. 3474-3487
Author(s):  
Ioannis M. Koukourakis ◽  
Marianthi Panteliadou ◽  
Axiotis G. Giakzidis ◽  
Christos Nanos ◽  
Ioannis Abatzoglou ◽  
...  

We report long-term results (median follow-up 12 years) of hypofractionated accelerated radiotherapy (HypoAR) in patients treated with breast-conserving surgery. In total, 367 women were treated with HypoAR. Axillary and supraclavicular area (ASA) were treated in patients with involved nodes. In total, 290 patients (scheme A) received 3.5 Gy/day ×10 fractions (breast/ASA) followed by two 4 Gy fractions with electrons to the affected breast quadrant within 16 days. In total, 77 patients (Scheme B) received 2.7 Gy/day for 16 consecutive fractions (breast/ASA) within 22 days, while concurrently, the affected breast quadrant received an electron booster dose of 0.8 Gy for the first 13 fractions. Amifostine was offered to 252/367 patients. Early radiation toxicity was minimal. Regarding late toxicities, symptomatic breast edema was noted in 2.2%, asymptomatic breast fibrosis in 1.9%, and arm lymphedema in 3.7% of patients. Amifostine reduced early radiation dermatitis (p = 0.001). In total, 2.2% of patients developed contralateral breast and 1.6% other carcinomas. Locoregional recurrence (LR) occurred in 3.1% of patients (0% for in situ carcinomas). Positive margins after surgery, extracapsular node invasion, and HER2-enriched/triple-negative tumors were linked with significantly worse LR-free survival. The involvement of more than three nodes and luminal type other than A were independent prognostic variables of metastasis and death events. HypoAR delivering a biological dose of 50–52 Gy to the breast/ASA is a safe and effective therapy for patients treated with conservative surgery. The risk of carcinogenesis is low. Positive surgical margins, extracapsular node invasion, and HER2-enriched/triple-negative phenotypes appear as a cluster of features linked with a higher risk for locoregional relapse.


2021 ◽  
Vol 22 (11) ◽  
pp. 6023
Author(s):  
Hoang Ngoc Tran ◽  
Flore Chappuis ◽  
Sébastien Incerti ◽  
Francois Bochud ◽  
Laurent Desorgher

In this work, we use the next sub-volume method (NSM) to investigate the possibility of using the compartment-based (“on-lattice”) model to simulate water radiolysis. We, first, start with a brief description of the reaction-diffusion master equation (RDME) in a spatially discretized simulation volume (“mesh”), which is divided into sub-volumes (or “voxels”). We then discuss the choice of voxel size and merging technique of a given mesh, along with the evolution of the system using the hierarchical algorithm for the RDME (“hRDME”). Since the compartment-based model cannot describe high concentration species of early radiation-induced spurs, we propose a combination of the particle-based step-by-step (“SBS”) Brownian dynamics model and the compartment-based model (“SBS-RDME model”) for the simulation. We, finally, use the particle-based SBS Brownian dynamics model of Geant4-DNA as a reference to test the model implementation through several benchmarks. We find that the compartment-based model can efficiently simulate the system with a large number of species and for longer timescales, beyond the microsecond, with a reasonable computing time. Our aim in developing this model is to study the production and evolution of reactive oxygen species generated under irradiation with different dose rate conditions, such as in FLASH and conventional radiotherapy.


2021 ◽  
Vol 77 (1) ◽  
pp. 25-28
Author(s):  
N.V. Kovalenko ◽  
◽  
V.V. Zhavoronkova ◽  
A.I. Ivanov ◽  
E.B. Petrova ◽  
...  

The article represents the first experience of using stereotaxic radiation therapy in hypofractionational mode and radiosurgery for metastatic brain lesions in the radiotherapy department of the Volgograd Regional Clinical Oncological Dispensary. The study involved 15 patients with secondary metastatic brain lesions by tumors of various localizations. Complete tumor regression was recorded in 4 (27 %) patients. In 10 (67 %) cases, a positive response was noted in the form of a decrease in tumor size from 50 to 20 %. No early radiation complications and deaths were detected during radiation therapy.


2021 ◽  
Vol 9 ◽  
Author(s):  
Patrick Blomenkemper ◽  
Robert Bäumer ◽  
Malte Backer ◽  
Abdalla Abu Hamad ◽  
Jun Wang ◽  
...  

Bennettitaleans are an extinct group of gymnosperms that are among the most iconic plants of Earth’s vegetation during the Mesozoic Era. The sudden appearance and rise to dominance of the Bennettitales during the Triassic remains a mystery. Leaf fossils similar to typical bennettitalean foliage occur in late Paleozoic deposits worldwide, but bennettitalean foliage can be identified with certainty only in case the fossils are sufficiently well-preserved to show epidermal features. So far, the characteristic stomatal architecture of the group has never been systematically documented in these putative Paleozoic remains. Here, we present well-preserved bennettitalean leaves from Permian deposits in two widely separated regions of equatorial Pangea. Two species of cuticle-bearing leaf compressions from the late Permian Umm Irna Formation, Jordan, are here formally described as Pterophyllum pottii Bomfleur et Kerp sp. nov. and Nilssoniopteris jogiana Blomenkemper et Abu Hamad sp. nov. Moreover, bulk maceration of samples from the Umm Irna Formation yielded six additional types of dispersed bennettitalean cuticles that are here informally described. In addition, the Cisuralian (early Permian) uppermost part of the Upper Shihhotse Formation exposed at the Palougou section in Shanxi Province, China, has yielded the oldest unambiguous bennettitalean fossils known to date; they consist of fragments of entire-margined leaves with well-preserved cuticles that we assign to Nilssoniopteris shanxiensis Bäumer, Backer et Wang sp. nov. Unlike the characteristic puzzle-patterned cuticles typical of many Jurassic and Cretaceous bennettites, the cuticles of these Permian bennettitalean remains show non-sinuous anticlinal walls, greater variety in stomatal orientation, and rare occurrence of transversely divided subsidiary cells—features that have until now almost exclusively been documented from the hitherto oldest cuticle-bearing Triassic bennettitalean material. Finally, the taxonomic richness, disjunct distribution, and broad variety in macro- and micromorphological features in these Permian bennettitalean remains lead us to suspect that the origin of the group will date back still further in time, and might in fact coincide with very early occurrences of Bennettitales-like foliage from the Pennsylvanian and Cisuralian, such as Pterophyllum cottaeanum, P. eratum, or P. grandeuryi.


Author(s):  
Kremena Petrova ◽  
Lena Marinova ◽  
Zdravko Yankov ◽  
Dimka Nikolaeva

For the first time in the English medical literature we present two adulthood clinical cases with medulloblastoma leptomeningeal disease (LMD) in which we have performed second craniospinal irradiation (re-CSI) using bias volumetric-modulated arc therapy (VMAT) technique. In this article we present bias volumetric-modulated arc therapy (VMAT) technique for repeated CSI (re-CSI) in two patients with adulthood medulloblastoma leptomeningeal disease (LMD). In both clinical cases (case1/case2) with adulthood medulloblastoma LMD, re-CSI has been performed using the bias VMAT technique in the area of the spinal cord up to total dose (TD) - 24 Gy/32 Gy; cauda equina up to TD- 28 Gy/38 Gy; in the cerebellum up to TD- 24 Gy/28 Gy; both cerebral hemispheres up to TD- 26 Gy/32 Gy and the cerebral ventricles up to TD-30 Gy/38 Gy with daily dose (DD)-1.8 Gy (17/21fractions). We describe in detail the stages of dosimetry planning of this radiotherapy technique, presenting its advantages and disadvantages, the observed early radiation toxicity and the possible treatment outcome. Volumetric-modulated radiotherapy with bias dose VMAT technique in adulthood medulloblastoma patients achieves improved dose homogeneity at the junction of the fields, increased compliance with the target volume and minimized dose to the organs at risk (OARs).


Zootaxa ◽  
2021 ◽  
Vol 4920 (4) ◽  
pp. 451-494
Author(s):  
JAVIER E. COLMENARES-PINZÓN

Neacomys Thomas, 1900 is an oryzomyine genus comprising at least 17 lineages distributed from easternmost Panama to northern Bolivia. As is the case for other groups of the subfamily Sigmodontinae, Neacomys have experienced a substantial increase in the rate of species descriptions in the last two decades, prompted by the progressive generation of morphological, molecular and karyological data. Nevertheless, most of the studies related to the genus have focused on the assessment of Cis-Andean populations, so that the Trans-Andean ones have been relegated to the background. In more than a century, only two species have been described from that region, one of them present in Colombia (N. tenuipes Thomas, 1900). Here, a new species of Neacomys is named and described based on samples collected in montane ecosystems of the Serranía de los Yariguíes, an isolated massif in the Magdalena Valley (Trans-Andean Colombia). Its validity is supported by a unique combination of morphological and molecular characters: Neacomys sp. nov. can be distinguished from other congeners mainly by the presence of broad ochraceous-orange patches on the sides of the muzzle, a gray-based ochraceous buff ventral fur, a thick hamular process of the squamosal, an opened ectotympanic ring, and a narrow anterocone of M1. The species is recovered as a clearly divergent and well-supported monophyletic group in the phylogenies, which implies it is not closely related to any other species in the genus and probably represents an early radiation within it. The new species of Neacomys constitutes the only rodent described from Colombia in more than 50 years and brings the list of mammals of the country to 529 species. Its discovery evidences that Trans-Andean region could be an important source of hidden diversity for the genus, and in Colombia, for rodents in general. Thus, further inventories, especially into remote areas, are needed to unveil this diversity. The fact that the new species seems to be endemic to an isolated mountain range implies it merits attention in terms of conservation. 


2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Ning Bao ◽  
Yuta Kikuchi

Abstract In the Hayden-Preskill thought experiment, the Hawking radiation emitted before a quantum state is thrown into the black hole is used along with the radiation collected later for the purpose of decoding the quantum state. A natural question is how the recoverability is affected if the stored early radiation is damaged or subject to decoherence, and/or the decoding protocol is imperfectly performed. We study the recoverability in the thought experiment in the presence of decoherence or noise in the storage of early radiation.


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