15,082 research outputs found
Toward eradication of B-vitamin deficiencies : considerations for crop biofortification
'Hidden hunger' involves insufficient intake of micronutrients and is estimated to affect over two billion people on a global scale. Malnutrition of vitamins and minerals is known to cause an alarming number of casualties, even in the developed world. Many staple crops, although serving as the main dietary component for large population groups, deliver inadequate amounts of micronutrients. Biofortification, the augmentation of natural micronutrient levels in crop products through breeding or genetic engineering, is a pivotal tool in the fight against micronutrient malnutrition (MNM). Although these approaches have shown to be successful in several species, a more extensive knowledge of plant metabolism and function of these micronutrients is required to refine and improve biofortification strategies. This review focuses on the relevant B-vitamins (B1, B6, and B9). First, the role of these vitamins in plant physiology is elaborated, as well their biosynthesis. Second, the rationale behind vitamin biofortification is illustrated in view of pathophysiology and epidemiology of the deficiency. Furthermore, advances in biofortification, via metabolic engineering or breeding, are presented. Finally, considerations on B-vitamin multi-biofortified crops are raised, comprising the possible interplay of these vitamins in planta
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The Haptic Bracelets: Gait rehabilitation after Stroke
Restoring mobility and rehabilitation of gait are high priorities for rehabilitation of neurological conditions. Cueing using metronomic rhythmic sensory stimulation has been shown to improve gait, but most versions of this approach have used auditory and visual cues. In contrast, we propose the development of a prototype wearable system for rhythmic cueing based on haptics. The main aim of this research is to investigate how real-time gait monitoring and rhythmic haptic cueing can assist with gait rehabilitation for neurological conditions
Simulations of the tidal interaction and mass transfer of a star in an eccentric orbit around an intermediate-mass black hole: the case of HLX-1
The X-ray source HLX-1 near the spiral galaxy ESO 243-49 is currently the
best intermediate-mass black hole candidate. It has a peak bolometric
luminosity of erg s, which implies a mass inflow rate of
MSun yr, but the origin of this mass is unknown. It has
been proposed that there is a star on an eccentric orbit around the black hole
which transfers mass at pericentre. To investigate the orbital evolution of
this system, we perform stellar evolution simulations using mesa and SPH
simulations of a stellar orbit around an intermediate-mass black hole using fi.
We run and couple these simulations using the amuse framework. We find that
mass is lost through both the first and second Lagrange points and that there
is a delay of up to 10 days between the pericentre passage and the peak mass
loss event. The orbital evolution timescales we find in our simulations are
larger than what is predicted by analytical models, but these models fall
within the errors of our results. Despite the fast orbital evolution, we are
unable to reproduce the observed change in outburst period. We conclude that
the change in the stellar orbit with the system parameters investigated here is
unable to account for all observed features of HLX-1.Comment: accepted for publication in mnra
The first comprehensive LC–MS/MS method allowing dissection of the thiamine pathway in plants
Arabidopsis thaliana serves as a model plant for genetic research, including vitamin research. When aiming at engineering the thiamine (vitamin B1) pathway in plants, the availability of tools that allow the quantitative determination of different intermediates in the biosynthesis pathway is of pivotal importance. This is a challenge, given the nature of the compounds and the minute quantities of genetically engineered material that may be available for analysis. Here, we report on the first LC–MS/MS method for the simultaneous quantification of thiamine, its mono- and diphosphate derivatives and its precursors 4-methyl-5-(2-hydroxyethyl) thiazole (HET) and 4-amino-2-methyl-5-hydroxymethylpyrimidine (HMP). This method was optimized and validated for the quantitative determination of these analytes in Arabidopsis thaliana. All analytes were chromatographically separated within less than 2.5 min during an 8 min run. No unacceptable interferences were found. The method was fully validated based on international guidelines. Accuracy (%bias) and total imprecision (%CV) were within preset acceptance criteria for all analytes in both QC and real samples. All analytes were stable in extracted samples when stored for 48 h at 4 °C (autosampler stability) and when reanalyzed after storage at −80 °C and −20 °C for 2 weeks (freeze/thaw stability). We demonstrated the start material should be stored at −80 °C to ensure stability of all analytes during short- and long-term storage (up to 3 months). The validity and applicability of the developed procedure was demonstrated via its successful application on Arabidopsis lines, genetically engineered to enhance thiamine content
Simulating stellar winds in AMUSE
We present stellar_wind.py, a module that provides multiple methods of
simulating stellar winds using smoothed particle hydrodynamics codes (SPH)
within the astrophysical multipurpose software environment (AMUSE) framework.
With the simple wind mode, we create SPH wind particles in a spherically
symmetric shell. We inject the wind particles with a velocity equal to their
terminal velocity. The accelerating wind mode is similar, but with this method
particles can be injected with a lower initial velocity than the terminal
velocity and they are accelerated away from the star according to an
acceleration function. With the heating wind mode, SPH particles are created
with zero initial velocity with respect to the star, but instead wind particles
are given an internal energy based on the integrated mechanical luminosity of
the star. This mode is designed to be used on longer timescales and larger
spatial scales compared to the other two modes and assumes that the star is
embedded in a gas cloud. For fast winds, we find that both the simple and
accelerating mode can reproduce the desired velocity, density and temperature
profiles. For slow winds, the simple wind mode is insufficient due to dominant
hydrodynamical effects that change the wind velocities. The accelerating mode,
with additional options to account for these hydrodynamical effects, can still
reproduce the desired wind profiles. We test the heating mode by simulating
both a normal wind and a supernova explosion of a single star in a uniform
density medium. The stellar wind simulation results matches the analytical
solution for an expanding wind bubble. The supernova simulation gives
qualitatively correct results, but the simulated bubble expands faster than the
analytical solution predicts. We conclude with an example of a triple star
system which includes the colliding winds of all three stars.Comment: Accepted for publication in A&
Extragalactic H3O+: Some Consequences
We discuss some implications of our recent detection of extragalactic H3O+:
the location of the gas in M82, the origin of energetic radiation in M82, and
the possible feedback effects of star formation on the cosmic ray flux in
galaxies.Comment: Five pages, one figure; contribution to proceedings of conference
"Far-infrared observations of the interstellar medium", December 2007, Bad
Honne
Making Informed Decisions:the Value of Testing Strategies in Healthcare
In this thesis, I cover many aspects related to the economics of testing strategies in healthcare, from the organization of screening tests to the use of diagnostics to combat antimicrobial resistance. It is important to consider the testing infrastructure: where should testing take place, close to the patient or in specialized laboratories; who should perform the test and how are these health professionals organized; and what value do the test results have for public health and how are these data shared? These are some of the issues to be considered when deciding when to implement or reimburse tests. From a cost-effectiveness perspective, the underlying clinical data should be sufficient to compare the testing strategy to other health technologies, by using generalizable health outcomes, such as quality-adjusted life years, and by using sufficiently long time hori¬zons. In a cost-effectiveness analysis, the costs for society are related to the clinical benefits for patients, but for microbiological tests, the clinical value is broader than that, especially if tests can identify specific pathogens. The collected data can be used to make public health decisions, for example by updating treatment guidelines for infectious disease and by responding to antimicrobial resistance and potentially pandemic pathogens
The impacts of biofuel targets on land-use change and food supply : a global CGE assessment
This study analyzes the long-term impacts of large-scale expansion of biofuels on land-use change, food supply and prices, and the overall economy in various countries or regions using a global computable general equilibrium model, augmented by a land-use module and detailed representation of biofuel sectors. The study finds that an expansion of global biofuel production to meet currently articulated or even higher national targets in various countries for biofuel use would reduce gross domestic product at the global level; however, the gross domestic product impacts are mixed across countries or regions. The expansion of biofuels would cause significant land re-allocation with notable decreases in forest and pasture lands in a few countries. The results also suggest that the expansion of biofuels would cause a reduction in food supply. Although the magnitude of the impact on food supply at the global level is not as large as perceived earlier, it would be significant in developing countries like India and those in Sub-Saharan Africa. Agricultural commodities such as sugar, corn, and oil seeds, which serve as the main biofuel feedstocks, would experience significant increases in their prices in 2020 compared with the prices at baseline due to the expansion of biofuels to meet the existing targets.Agribusiness,Food&Beverage Industry,Wetlands,Crops&Crop Management Systems,Renewable Energy
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