674 research outputs found
Evolution of Launch Concepts and Space Flight Operations
Space science - launching and space flight operation
Predominance of exotic and introduced species among sturgeons captured from the Baltic and North Seas and their watersheds, 1981-1999
Sturgeon catches (n = 256) from 1981-1999 reported mainly by commercial fishermen and anglers in German, Polish, and Dutch coastal waters and tributaries were analysed. During the study period, 20 % of catches were reported from coastal waters and 65 % from rivers and estuaries of large river systems, including the Odra, Elbe, Rhine and Weser. The data indicate that, from 1981- 1993, there was a major decline in the Atlantic sturgeon Acipenser sturio L., 1758, and an increase in the total catches of non-indigenous sturgeon species. The Siberian sturgeon Acipenser baerii Brandt, 1869, the Russian sturgeon Acipenser gueldenstaedtii Brandt & Ratzeberg, 1833, and various hybrids dominated. Occasional catches of the white sturgeon Acipenser transmontanus Richardson, 1836 and the sterlet Acipenser ruthenus L., 1758 were also reported. During the study period, significant changes in species composition and distribution of catches were observed. The predominance of non-indigenous sturgeon species is a result of the increasingly intensive sturgeon aquaculture activities in Germany, Poland, and the Netherlands. The most frequently reared species now dominate the catches. In addition to these escapees from fish farms, several intentional releases of sturgeons were reported. The results show that introduced exotic sturgeon species may thrive under certain natural conditions. Therefore, they may interfere with restoration efforts for the native A. sturio, competing for habitat and introducing diseases and hybridization.Se analizaron las capturas de esturiones (n = 256) entre 1981 y 1999 proporcionadas principalmente por pescadores profesionales y deportivos en las costas alemanas, polacas y holandesas, y en los sistemas fluviales que desembocan en ellas. En el periodo de estudio, el 20 % de las capturas correspondió a aguas litorales y el 65 % a ríos y estuarios de los grandes sistemas fluviales, incluidos los ríos Oder, Elba, Rin y Weser. Los datos indican que entre 1981 y 1993 tuvo lugar el mayor declive del esturión atlántico Acipenser sturio L., 1758 y un incremento en las capturas totales de las especies alóctonas de esturiones. Predominaron las capturas de esturión siberiano Acipenser baerii Brandt, 1869, esturión ruso Acipenser gueldenstaedtii Brandt & Ratzeberg, 1833 y varios híbridos. También se registraron capturas ocasionales de esturión blanco Acipenser transmontanus Richardson, 1836 y esterlete Acipenser ruthenus L., 1758. En el periodo de estudio se observaron cambios significativos en la composición de especies y en la distribución de las capturas. El predominio de las especies alóctonas de esturiones es el resultado de las crecientes actividades en la acuicultura intensiva de esturión en Alemania, Polonia y Países Bajos. Las especies cultivadas más frecuentemente dominan ahora las capturas. Además de estas fugas de las piscifactorías, se han registrado varias sueltas intencionadas. Los resultados muestran que las especies de esturiones exóticas introducidas pueden prosperar en ciertas condiciones naturales. Por esta razón, pueden interferir en los esfuerzos de restauración de la especie autóctona A. sturio, compitiendo por el hábitat e introduciendo enfermedades e hibridación.Instituto Español de Oceanografí
Biosensor Cell-Fit-HD4D for correlation of single-cell fate and microscale energy deposition in complex ion beams
We present a protocol for the biosensor Cell-Fit-HD4D. It enables long-term monitoring and correlation of single-cell fate with subcellular-deposited energy of ionizing radiation. Cell fate tracking using widefield time-lapse microscopy is uncoupled in time from confocal ion track imaging. Registration of both image acquisition steps allows precise ion track assignment to cells and correlation with cellular readouts. For complete details on the use and execution of this protocol, please refer to Niklas et al. (2022)
Excited States of Proton-bound DNA/RNA Base Homo-dimers: Pyrimidines
We are presenting the electronic photo fragment spectra of the protonated
pyrimidine DNA bases homo-dimers. Only the thymine dimer exhibits a well
structured vibrational progression, while protonated monomer shows broad
vibrational bands. This shows that proton bonding can block some non radiative
processes present in the monomer.Comment: We acknowledge the use of the computing facility cluster GMPCS of the
LUMAT federation (FR LUMAT 2764
Detailed analysis of the cell-inactivation mechanism by accelerated protons and light ions
Published survival data for V79 cells irradiated by monoenergetic protons,
helium-3, carbon, and oxygen ions and for CHO cells irradiated by carbon ions
have been analyzed using the probabilistic two-stage model of cell
inactivation. Three different classes of DNA damages formed by traversing
particles have been distinguished, namely severe single-track damages which
might lead to cell inactivation directly, less severe damages where cell
inactivation is caused by their combinations, and damages of negligible
severity that can be repaired easily. Probabilities of single ions to form
these damages have been assessed in dependence on their linear energy transfer
(LET) values.
Damage induction probabilities increase with atomic number and LET. While
combined damages play crucial role at lower LET values, single-track damages
dominate in high-LET regions. The yields of single-track lethal damages for
protons have been compared with the Monte Carlo estimates of complex DNA
lesions, indicating that lethal events correlate well with complex DNA
double-strand breaks. The decrease in the single-track damage probability for
protons of LET above approx. 30 keV/m, suggested by limited experimental
evidence, is discussed, together with the consequent differences in the
mechanisms of biological effects between protons and heavier ions. Applications
of the results in hadrontherapy treatment planning are outlined.Comment: submitted to Physics in Medicine and Biolog
Angioplasty in asymptomatic carotid artery stenosis vs. endarterectomy compared to best medical treatment: One-year interim results of SPACE-2
BACKGROUND Treatment of individuals with asymptomatic carotid artery stenosis is still handled controversially. Recommendations for treatment of asymptomatic carotid stenosis with carotid endarterectomy (CEA) are based on trials having recruited patients more than 15 years ago. Registry data indicate that advances in best medical treatment (BMT) may lead to a markedly decreasing risk of stroke in asymptomatic carotid stenosis. The aim of the SPACE-2 trial (ISRCTN78592017) was to compare the stroke preventive effects of BMT alone with that of BMT in combination with CEA or carotid artery stenting (CAS), respectively, in patients with asymptomatic carotid artery stenosis of \geq70% European Carotid Surgery Trial (ECST) criteria. METHODS SPACE-2 is a randomized, controlled, multicenter, open study. A major secondary endpoint was the cumulative rate of any stroke (ischemic or hemorrhagic) or death from any cause within 30 days plus an ipsilateral ischemic stroke within one year of follow-up. Safety was assessed as the rate of any stroke and death from any cause within 30 days after CEA or CAS. Protocol changes had to be implemented. The results on the one-year period after treatment are reported. FINDINGS It was planned to enroll 3550 patients. Due to low recruitment, the enrollment of patients was stopped prematurely after randomization of 513 patients in 36 centers to CEA (n = 203), CAS (n = 197), or BMT (n = 113). The one-year rate of the major secondary endpoint did not significantly differ between groups (CEA 2.5%, CAS 3.0%, BMT 0.9%; p = 0.530) as well as rates of any stroke (CEA 3.9%, CAS 4.1%, BMT 0.9%; p = 0.256) and all-cause mortality (CEA 2.5%, CAS 1.0%, BMT 3.5%; p = 0.304). About half of all strokes occurred in the peri-interventional period. Higher albeit statistically non-significant rates of restenosis occurred in the stenting group (CEA 2.0% vs. CAS 5.6%; p = 0.068) without evidence of increased stroke rates. INTERPRETATION The low sample size of this prematurely stopped trial of 513 patients implies that its power is not sufficient to show that CEA or CAS is superior to a modern medical therapy (BMT) in the primary prevention of ischemic stroke in patients with an asymptomatic carotid stenosis up to one year after treatment. Also, no evidence for differences in safety between CAS and CEA during the first year after treatment could be derived. Follow-up will be performed up to five years. Data may be used for pooled analysis with ongoing trials
Thyrotropin-releasing hormone (TRH) promotes wound re-epithelialisation in frog and human skin
There remains a critical need for new therapeutics that promote wound healing in patients suffering from chronic skin wounds. This is, in part, due to a shortage of simple, physiologically and clinically relevant test systems for investigating candidate agents. The skin of amphibians possesses a remarkable regenerative capacity, which remains insufficiently explored for clinical purposes. Combining comparative biology with a translational medicine approach, we report the development and application of a simple ex vivo frog (Xenopus tropicalis) skin organ culture system that permits exploration of the effects of amphibian skin-derived agents on re-epithelialisation in both frog and human skin. Using this amphibian model, we identify thyrotropin-releasing hormone (TRH) as a novel stimulant of epidermal regeneration. Moving to a complementary human ex vivo wounded skin assay, we demonstrate that the effects of TRH are conserved across the amphibian-mammalian divide: TRH stimulates wound closure and formation of neo-epidermis in organ-cultured human skin, accompanied by increased keratinocyte proliferation and wound healing-associated differentiation (cytokeratin 6 expression). Thus, TRH represents a novel, clinically relevant neuroendocrine wound repair promoter that deserves further exploration. These complementary frog and human skin ex vivo assays encourage a comparative biology approach in future wound healing research so as to facilitate the rapid identification and preclinical testing of novel, evolutionarily conserved, and clinically relevant wound healing promoters
Terahertz metamaterials on flexible polypropylene substrate
The final publication is available at Springer via http://dx.doi.org/10.1007/s11468-014-9724-1In this work, we present a metamaterial working at terahertz frequencies made over a flexible polypropylene sub-strate. The experimental measurements, in accordance with the numerical calculations, show the metamaterial reliance on the impinging electric field polarization. The structure s symmetry yields purely electrical resonant responses eliminating bianisotropy effects. The widely used bendable polypropylene polymer may promote the insertion of metamaterial-based structures with special electromagnetic response in a number of objects of our daily lives such as textiles, automotive components, and sensingThis work was supported by the Spanish MICINN under contracts CONSOLIDER EMET CSD2008-00066 and TEC2011-28664-C02-02 and by the Universitat Politecnica de Valencia under the program INNOVA 2011.Ortuño Molinero, R.; García Meca, C.; Martínez Abietar, AJ. (2014). 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