961 research outputs found
Comparative Effects of Heating and Fasting in Mice, with Particular Reference to Development of Sarcoma 180
Effects of heating and fasting, both alone and associated, have been studied in normal and Sarcoma 180 bearing mice. Heating reduced body weight and tumour mass and increased body temperature. Fasting reduced body weight, while tumour mass and body temperature were slightly affected. By associating heating and fasting a more marked decrease of body weight was produced than by each of the two factors involved, while effects on body temperature and on tumour mass were unchanged with respect to heating alone. 6-mercaptopurine was similar to heating in reducing body weight and tumour mass
Photo-autotrophic Production of Poly(hydroxyalkanoates) in Cyanobacteria
In the last two decades, poly(hydroxyalkanoates) (PHA) were solely produced using heterotrophic bacteria in aerobic cultivation. With respect to the great potential (500 Mt yr–1) of raw industrial CO2 streams and even greater potential of flue gases, the focus on photo-autotrophic biotechnological processes is increasing steadily. Primarily, PHA-gene transfer from heterotrophic bacteria into algae and plant cells was attempted, with the intention to combine the known biosynthesis pathway with autotrophic cultivation. The natural occurrence of PHA in cyanobacteria is known at least since 1966. However, cyanobacteria were never considered for commercial production because the PHA amount based on cell mass and based on volumetric productivity is generally very low. Therefore, strain improvements were suggested, either by gene amplification or by suppression of biochemical pathways competing for the cell’s acetate pool. In the late 1990s, the success of genetic modification was confirmed experimentally, elevating the cyanobacteria cell’s PHA content. With additional optimization, PHB amounts up to 50 % w/w of biomass dry matter or up to about 2.4 g L–1 bioreactor volume could be produced within 11 days. Considering the land use for agriculture and the competition for plant biomass between food, feed, fuel and energy production, the binding of CO2 in a biotechnological process using photo-autotrophic microorganisms may become a promising option
Inhomogeneous Superconductivity in Comb-Shaped Josephson Junction Networks
We show that some of the Josephson couplings of junctions arranged to form an
inhomogeneous network undergo a non-perturbative renormalization provided that
the network's connectivity is pertinently chosen. As a result, the zero-voltage
Josephson critical currents turn out to be enhanced along directions
selected by the network's topology. This renormalization effect is possible
only on graphs whose adjacency matrix admits an hidden spectrum (i.e. a set of
localized states disappearing in the thermodynamic limit). We provide a
theoretical and experimental study of this effect by comparing the
superconducting behavior of a comb-shaped Josephson junction network and a
linear chain made with the same junctions: we show that the Josephson critical
currents of the junctions located on the comb's backbone are bigger than the
ones of the junctions located on the chain. Our theoretical analysis, based on
a discrete version of the Bogoliubov-de Gennes equation, leads to results which
are in good quantitative agreement with experimental results.Comment: 4 pages, 2 figures, revte
BLUFF-BODIES VORTEX SHEDDING SUPRESSION BY DIRECT NUMERICAL SIMULATION
Vortex shedding is responsible for harmful vibrations on immersed
structures and for increasing their drag coefficients. Thus vortex shedding
suppression is highly interesting in order of decrease maintenance costs of
standing structures and fuel costs on moving ones. Vortex shedding
suppression is here achieved with the use of splitter plates by means of
numerical simulations at a low Reynolds range, Re 100 and 160. For this
purpose it has been used a high order finite difference method in association
with a virtual boundary method, responsible for the obstacles
representation. The use of this novel numerical method showed a great
concordance with experimental results by means of low computational
costs
The impact of SuperB on flavour physics
This report provides a succinct summary of the physics programme of SuperB,
and describes that potential in the context of experiments making measurements
in flavour physics over the next 10 to 20 years. Detailed comparisons are made
with Belle II and LHCb, the other B physics experiments that will run in this
decade. SuperB will play a crucial role in defining the landscape of flavour
physics over the next 20 years.Comment: 20 pages, 6 figure
Investigation of current noise in underdamped Josephson devices by switching current measurements
AbstractExperimental measurements on critical current noise in underdamped niobium based Josephson devices by a technique based on the switching current measurements is reported. By sweeping the junction with a current ramp we measure the critical current switching as a function of the time using the standard time of flight technique. In such a way it is possible to obtain the critical current fluctuations ΔIc=Ic(t)-<Ic(t)> and the relative standard deviations which corresponds to the root square of the current fluctuation power. Pointing at the white noise fluctuations (above few Hz) and taking into account the physical frequency of the device, it is possible to evaluate the power spectral density of the critical current. The analysis has involved high quality underdamped Josephson junctions having an area ranging from (4x4) μm2 to (40x40) μm2 in the temperature range from 4.2K to few tenth of mK. These measurement provide very useful information about the intrinsic noise of Josephson devices involving SQUIDs and qubits
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