50 research outputs found
The Isgur-Wise function in a relativistic model for system
We use the Dirac equation with a ``(asymptotically free) Coulomb + (Lorentz
scalar) linear '' potential to estimate the light quark wavefunction for mesons in the limit . We use these wavefunctions to
calculate the Isgur-Wise function for orbital and radial
ground states in the phenomenologically interesting range . We find a simple expression for the zero-recoil slope, , where is the energy eigenvalue
of the light quark, which can be identified with the parameter
of the Heavy Quark Effective Theory. This result implies an upper bound of
for the slope . Also, because for a very light quark the size of the meson is determined mainly by the
``confining'' term in the potential , the shape of
is seen to be mostly sensitive to the dimensionless
ratio . We present results for the ranges of
parameters , and
light quark masses and compare to existing
experimental data and other theoretical estimates. Fits to the data give:
,
and [ARGUS
'93]; , and
[CLEO '93]; ${\bar\Lambda_{u,d}}^2/Comment: 22 pages, Latex, 4 figures (not included) available by fax or via
email upon reques
Long Distance Contribution to and Implications for and
We estimate the long distance (LD) contribution to the magnetic part of the
transition using the Vector Meson Dominance approximation
. We find that this contribution may be significantly
larger than the short distance (SD) contribution to and could
possibly saturate the present experimental upper bound on the decay rate, eV. For the decay , which is driven by as well, we obtain an upper bound on the branching ratio from . Barring the possibility that the Quantum Chromodynamics
coefficient be much smaller than 1, also implies the approximate relation .
This relation agrees quantitatively with a recent independent estimate of the
l.h.s. by Deshpande et al., confirming that the LD contributions to are small. We find that these amount to an increase of in
the magnitude of the transition amplitude, relative to the SD
contribution alone.Comment: 16 pages, LaTeX fil
Highly Efficient Gene Editing of Cystic Fibrosis Patient-Derived Airway Basal Cells Results in Functional CFTR Correction
There is a strong rationale to consider future cell therapeutic approaches for cystic fibrosis (CF) in which autologous proximal airway basal stem cells, corrected for CFTR mutations, are transplanted into the patient's lungs. We assessed the possibility of editing the CFTR locus in these cells using zinc-finger nucleases and have pursued two approaches. The first, mutation-specific correction, is a footprint-free method replacing the CFTR mutation with corrected sequences. We have applied this approach for correction of ÎF508, demonstrating restoration of mature CFTR protein and function in air-liquid interface cultures established from bulk edited basal cells. The second is targeting integration of a partial CFTR cDNA within an intron of the endogenous CFTR gene, providing correction for all CFTR mutations downstream of the integration and exploiting the native CFTR promoter and chromatin architecture for physiologically relevant expression. Without selection, we observed highly efficient, site-specific targeted integration in basal cells carrying various CFTR mutations and demonstrated restored CFTR function at therapeutically relevant levels. Significantly, Omni-ATAC-seq analysis revealed minimal impact on the positions of open chromatin within the native CFTR locus. These results demonstrate efficient functional correction of CFTR and provide a platform for further ex vivo and in vivo editing. © 2020 The American Society of Gene and Cell TherapySuzuki et al. report correction of the CFTR defect in cystic fibrosis airway basal stem cells. They utilized gene-editing strategies either specific for the ÎF508 CFTR mutation or applicable to most CFTR mutations. Both approaches yielded highly efficient correction without selection, restoring CFTR function to therapeutically relevant levels
Use of space by neotropical marsupial Didelphis albiventris (Didelphimorphia: Didelphidae) in an urban forest fragment
Long-term effects of medical management on growth and weight in individuals with urea cycle disorders
Low protein diet and sodium or glycerol phenylbutyrate, two pillars of recommended long-term therapy of individuals with urea cycle disorders (UCDs), involve the risk of iatrogenic growth failure. Limited evidence-based studies hamper our knowledge on the long-term effects of the proposed medical management in individuals with UCDs. We studied the impact of medical management on growth and weight development in 307 individuals longitudinally followed by the Urea Cycle Disorders Consortium (UCDC) and the European registry and network for Intoxication type Metabolic Diseases (E-IMD). Intrauterine growth of all investigated UCDs and postnatal linear growth of asymptomatic individuals remained unaffected. Symptomatic individuals were at risk of progressive growth retardation independent from the underlying disease and the degree of natural protein restriction. Growth impairment was determined by disease severity and associated with reduced or borderline plasma branched-chain amino acid (BCAA) concentrations. Liver transplantation appeared to have a beneficial effect on growth. Weight development remained unaffected both in asymptomatic and symptomatic individuals. Progressive growth impairment depends on disease severity and plasma BCAA concentrations, but cannot be predicted by the amount of natural protein intake alone. Future clinical trials are necessary to evaluate whether supplementation with BCAAs might improve growth in UCDs
A História da Alimentação: balizas historiogråficas
Os M. pretenderam traçar um quadro da HistĂłria da Alimentação, nĂŁo como um novo ramo epistemolĂłgico da disciplina, mas como um campo em desenvolvimento de prĂĄticas e atividades especializadas, incluindo pesquisa, formação, publicaçÔes, associaçÔes, encontros acadĂȘmicos, etc. Um breve relato das condiçÔes em que tal campo se assentou faz-se preceder de um panorama dos estudos de alimentação e temas correia tos, em geral, segundo cinco abardagens Ia biolĂłgica, a econĂŽmica, a social, a cultural e a filosĂłfica!, assim como da identificação das contribuiçÔes mais relevantes da Antropologia, Arqueologia, Sociologia e Geografia. A fim de comentar a multiforme e volumosa bibliografia histĂłrica, foi ela organizada segundo critĂ©rios morfolĂłgicos. A seguir, alguns tĂłpicos importantes mereceram tratamento Ă parte: a fome, o alimento e o domĂnio religioso, as descobertas europĂ©ias e a difusĂŁo mundial de alimentos, gosto e gastronomia. O artigo se encerra com um rĂĄpido balanço crĂtico da historiografia brasileira sobre o tema
SUMMARY REPORT ON ANALYSIS OF THE SEMI-FLUID CONDITION IN THE PG-6 PHOSPHATE GLASS SOLIDS CONTAINER.
Recommended from our members
High-level radioactive waste management research and development program at Battelle Pacific Northwest Laboratories
Recommended from our members
Research and development activities: high-level waste immobilization program. Quarterly progress report, January-March 1979
Liquid waste, made from zirconium-clad UO/sub 2/ power reactor fuel with an average burnup of 25,000 MWd/MT, was converted to glass by the in-can melting process. An intrinsic-gamma melt-level detection system was tested during the NWVP demonstrations; results showed that if a sufficient number of collimators are used the system will track the melt surface with a precision of 1 in. during the filling of cans with waste glass. The two canisters filled in the NWVP are both 8 in. in diameter and contain borosilicate glass of very similar compositions. One canister contains 116 kg of glass that generated 0.38 kW of self-heat when produced; the other contains 145 kg of glass, and generates 1.01 kW. Spray calcination of simulated Savannah River Plant liquid waste at a rate of 400 L/h was demonstrated in the 36-in.-dia. calciner. Five waste forms are being compared: concrete-containing waste calcine, sintered waste glass, glass-ceramic, Synroc B (a crystalline assemblage of titanates), and borosilicate waste glass (composition 76-68). Results of initial tests indicate that the reaction rate of carbon with water, previously found to be very low, may be increased in a radiation field