5,456 research outputs found
Regeneration ability and genetic transformation of root type chicory (Cichorium intybus var. sativum)
To develop an efficient protocol for shoot regeneration of root chicory (Cichorium intybus var. sativum), some factors, including different concentrations of plant growth regulators in Murashige and Skoog (MS) medium, type of explants and genotypes were evaluated. Initiation of callusing were best achieved in MS medium supplemented with 1-naphthaleneacetic acid (NAA) (0.1 mg l-1) plus 6-Benzylaminopurine (6-BAP) (1 mg l-1), indole-3-acetic acid (IAA) (0.01 mg l-1) plus 6-BAP (1.0 mg l-1), and IAA (0.5 mg l-1) plus (0.5 mg l-1) 6-BAP combinations on leaf and cotyledon explants. Explant-derived calli were able to produce multiple adventitious shoots in MS medium containing IAA (0.5 mg l-1) plus 6-BAP (0.5 mg l-1). MS medium containing indole-3-butylric acid IBA (1 mgl-1) efficiently induced rooting on elongated shoots. Various responses to the number of generated shoots were observed when regeneration abilities of different chicory cultivars were examined. Among root and âWitloofâ cultivars, âMelciâ and âHeraâ belong to the root cultivars and exhibited higher shoot regeneration ability. Using the optimized regeneration method, genetic transformation of âMelciâ with Agrobacterium tumefaciens strain C58C1 RifR (pGV2260) (pTJK136) was successfully carried out. Histochemical GUS assay, polymerase chain reaction (PCR) and reverse transcription-polymerase chain reaction (RT-PCR) analysis of putative transformed plants confirmed successful integration of the T-DNA into the chicory genome. Expression of the neomycine phosphotransferase (NPTII) in the regenerated plants was also shown by well-developed roots on root inducing medium containing 100 mg l-1 kanamycin. This simple, efficient and reproducible protocol could be useful for inducing somaclonal variation and genetic modification of root chicory cultivars to broaden genetic variation and transferring of important genes
What sets the magnetic field strength and cycle period in solar-type stars?
Two fundamental properties of stellar magnetic fields have been determined by
observations for solar-like stars with different Rossby numbers (Ro), namely,
the magnetic field strength and the magnetic cycle period. The field strength
exhibits two regimes: 1) for fast rotation it is independent of Ro, 2) for slow
rotation it decays with Ro following a power law. For the magnetic cycle period
two regimes of activity, the active and inactive branches, also have been
identified. For both of them, the longer the rotation period, the longer the
activity cycle. Using global dynamo simulations of solar like stars with Rossby
numbers between ~0.4 and ~2, this paper explores the relevance of rotational
shear layers in determining these observational properties. Our results,
consistent with non-linear alpha^2-Omega dynamos, show that the total magnetic
field strength is independent of the rotation period. Yet at surface levels,
the origin of the magnetic field is determined by Ro. While for Ro<1 it is
generated in the convection zone, for Ro>1 strong toroidal fields are generated
at the tachocline and rapidly emerge towards the surface. In agreement with the
observations, the magnetic cycle period increases with the rotational period.
However, a bifurcation is observed for Ro~1, separating a regime where
oscillatory dynamos operate mainly in the convection zone, from the regime
where the tachocline has a predominant role. In the latter the cycles are
believed to result from the periodic energy exchange between the dynamo and the
magneto-shear instabilities developing in the tachocline and the radiative
interior.Comment: 43 pages, 14 figures, accepted for publication in The Astrophysical
Journa
Antiferromagnetism and charged vortices in high-Tc superconductors
The effect of the long-range Coulomb interaction on charge accumulation in
antiferromagnetic vortices in high-Tc superconductors is studied within a
Bogoliubov-de Gennes mean-field model of competing antiferromagnetic and d-wave
superconducting orders. Antiferromagnetism is found to be associated with an
accumulation of charge in the vortex core, even in the presence of the
long-range Coulomb interaction. The manifestation of Pi-triplet pairing in the
presence of coexisting dSC and AFM order, and the intriguing appearance of
one-dimensional stripe-like ordering are discussed. The local density of states
(LDOS) in the vortex core is calculated and is found to be in excellent
qualitative agreement with experimental data.Comment: 14 pages, 8 figures, 2 column RevTex4 PRB forma
Regeneration ability and genetic transformation of root type chicory (Cichorium intybus var. sativum)
To develop an efficient protocol for shoot regeneration of root chicory (Cichorium intybus var. sativum), some factors, including different concentrations of plant growth regulators in Murashige and Skoog (MS) medium, type of explants and genotypes were evaluated. Initiation of callusing were best achieved in MS medium supplemented with 1-naphthaleneacetic acid (NAA) (0.1 mg l-1) plus 6-Benzylaminopurine (6-BAP) (1 mg l-1), indole-3-acetic acid (IAA) (0.01 mg l-1) plus 6-BAP (1.0 mg l-1), and IAA (0.5 mg l-1) plus (0.5 mg l-1) 6-BAP combinations on leaf and cotyledon explants. Explant-derived calli were able to produce multiple adventitious shoots in MS medium containing IAA (0.5 mg l-1) plus 6-BAP (0.5 mg l-1). MS medium containing indole-3-butylric acid IBA (1 mgl-1) efficiently induced rooting on elongated shoots. Various responses to the number of generated shoots were observed when regeneration abilities of different chicory cultivars were examined. Among root and âWitloofâ cultivars, âMelciâ and âHeraâ belong to the root cultivars and exhibited higher shoot regeneration ability. Using the optimized regeneration method, genetic transformation of âMelciâ with Agrobacterium tumefaciens strain C58C1 RifR (pGV2260) (pTJK136) was successfully carried out. Histochemical GUS assay, polymerase chain reaction (PCR) and reverse transcription-polymerase chain reaction (RT-PCR) analysis of putative transformed plants confirmed successful integration of the T-DNA into the chicory genome. Expression of the neomycine phosphotransferase (NPTII) in the regenerated plants was also shown by well-developed roots on root inducing medium containing 100 mg l-1 kanamycin. This simple, efficient and reproducible protocol could be useful for inducing somaclonal variation and genetic modification of root chicory cultivars to broaden genetic variation and transferring of important genes.Keywords: Chicory, regeneration, transformation, 1-Naphthaleneacetic acid (NAA), indole-3-acetic acid (IAA), 6-Benzylaminopurine (6-BAP
Fluctuations in fluids in thermal nonequilibrium states below the convective Rayleigh-Benard instability
Starting from the linearized fluctuating Boussinesq equations we derive an
expression for the structure factor of fluids in stationary convection-free
thermal nonequilibrium states, taking into account both gravity and finite-size
effects. It is demonstrated how the combined effects of gravity and finite size
causes the structure factor to go through a maximum value as a function of the
wave number . The appearance of this maximum is associated with a crossover
from a dependence for larger to a dependence for very small
. The relevance of this theoretical result for the interpretation of light
scattering and shadowgraph experiments is elucidated. The relationship with
studies on various aspects of the problem by other investigators is discussed.
The paper thus provides a unified treatment for dealing with fluctuations in
fluid layers subjected to a stationary temperature gradient regardless of the
sign of the Rayleigh number , provided that is smaller than the critical
value associated with the appearance of Rayleigh-B\'{e}nard
convection.Comment: 33 pages, 6 figures, accepted for publication: Physica
Anatomy of surgical exposure course: does it add to trainee experiences?
The Royal Australasian College of Surgeons lists 11 accredited postgraduate anatomy courses in Australia and New Zealand. These courses vary in their teaching syllabus, length and emphasis. The anatomy of surgical exposure (ASE) course held by James Cook University in conjunction with the Northern Clinical Training Network is unique among the anatomy courses in that it covers an entire operative surgical curriculum in open general surgery on cadavers. Understanding reasons, expectations and outcomes of participants can better inform the educational debate relating to anatomy teaching and help meet the training and educational needs of surgical trainees. An exploratory approach, using in depth phone interviews was used to understand the 2016 ASE course cohort ideas and perceptions on how surgical anatomy teaching improved their learning and careers Participantâs conceptions of learning anatomy in surgery and reïŹnement of basic surgical exposure skills were identiïŹed as a key learning outcome. The reasons for joining the course where multi-faceted and related to lack of open-surgical opportunities in training, improving basic tissue handling and advancing experience to make the individual competitive for training programmes
Distribution of \u3ci\u3eEscherichia coli\u3c/i\u3e Passaged through Processing Equipment during Ground Beef Production Using Inoculated Trimmings
The contamination of raw ground beef by Escherichia coli O157:H7 is not only a public health issue but also an economic concern to meat processors. When E. coli O157:H7 is detected in a ground beef sample, the product lots made immediately before and after the lot represented by the positive sample are discarded or diverted to lethality treatment. However, there is little data to base decisions on how much product must be diverted. Therefore, five 2,000-lb (907-kg) combo bins of beef trimmings were processed into 10-lb (4.54-kg) chubs of raw ground beef, wherein the second combo of meat was contaminated with a green fluorescent protein (GFP)âexpressing strain of E. coli. This was performed at two different commercial ground beef processing facilities, and at a third establishment where ground beef chubs from the second grinding establishment were mechanically split and repackaged into 3-lb (1.36-kg) loaves in trays. The GFP E. coli was tracked through the production of 10-lb (4.54-kg) chubs and the strain could not be detected after 26.5% more material (500 lb or 227 kg) and 87.8% more material (1,840 lb or 835 kg) followed the contaminated combo at each establishment, respectively. Three-pound (1.36-kg) loaves were no longer positive after just 8.6% more initially noncontaminated material (72 lb or 33 kg) was processed. The GFP strain could not be detected postprocessing in any residual meat or fat collected from the equipment used in the three trials. These results indicate that diversion to a safe end point (lethality or rendering) of the positive lot of ground beef, plus the lot before and lot after should remove contaminated ground beef, and as such provides support for the current industry practice. Further, the distribution and flow of E. coli on beef trimmings through various commercial equipment was different; thus, each establishment needs to consider this data when segregating lots of ground beef and establishing sampling protocols to monitor production
SARS-CoV-2 Breakthrough Infections: Incidence and Risk Factors in a Large European Multicentric Cohort of Health Workers
Impact de l'Hépatite Delta sur la fibrose hépatique mesurée par élastométrie impulsionnelle
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