49 research outputs found
The earlier identification of the seedless characteristic of the wampee [Clausena lansium (Lour.) Skeels] hybrid by a random amplified polymorphic DNA (RAPD) marker
Wampee as an important fruit is widely grown in South China and conventional breeding methods for the production of new seedless wampee cultivars in recent years were operated. Hybridization wasconducted using the seed as female parents and the seedless as male parents. However, the seeds could be gotten from cross combination. An efficient operation was that, non-woven fabrics bag could increase burliness rate in hybridization. In order to earlier identify seedless seedlings in hybrid progeny, the objective of this work is to identify molecular markers linked to seedless trait through bulked segregant analysis. Two bulks, seedless and seed, were prepared by pooling DNA of individual identified plants and used in polymerase chain reaction (PCR) analysis. Out of the 100 primers tested, only S06 primer could get a specific 930 bp restriction random amplified polymorphic DNA (RAPDamplicon to seedless bulk. As a result, a hybrid was tested with this primer in two cross combinations.Keywords: Earlier identification, seedless wampee, bulked segregant analysis, randomly amplified polymorphic DN
Studies of the genetic diversity of seven sweetsop (Annona squamosa L.) cultivars by amplified fragment length polymorphism analysis
Seven sweetsop germplasm resources were studied, and amplified fragment length polymorphism (AFLP) analysis system was established by detecting the results of several reactions, such as DNA extraction, enzyme restriction, ligation, preamplification and selective amplification in the reaction system of AFLP. The seven germplasm resources of sweetsop were studied by using AFLP technique, and UPGMA clustering results showed genetic distance of 0.572 ~ 0.818. Small genetic distance was 0.572 between âYuanhuaâ sweetsop and other sweetsop cultivars; high genetic distance was 0.818 between âAPâ and âFenglishijiaâ sweetsop. These results suggested that there was relative family relationship between them. This aims to study the family relationship in seven sweetsop germplasms resources, in order to select parents in sweetsop breeding and grafted rootstock.Key words: Sweetsop, DNA extraction, amplified fragment length polymorphism (AFLP), genetic diversity
Molecular Russian dolls
The host-guest recognition between two macrocycles to form hierarchical non-intertwined ring-in-ring assemblies remains an interesting and challenging target in noncovalent synthesis. Herein, we report the design and characterization of a box-in-box assembly on the basis of host-guest radical-pairing interactions between two rigid diradical dicationic cyclophanes. One striking feature of the box-in-box complex is its ability to host various 1,4-disubstituted benzene derivatives inside as a third component in the cavity of the smaller of the two diradical dicationic cyclophanes to produce hierarchical Russian doll like assemblies. These results highlight the utility of matching the dimensions of two different cyclophanes as an efficient approach for developing new hybrid supramolecular assemblies with radical-paired ring-in-ring complexes and smaller neutral guest molecules
Nuclear Reaction Network for Primordial Nucleosynthesis: a detailed analysis of rates, uncertainties and light nuclei yields
We analyze in details the standard Primordial Nucleosynthesis scenario. In
particular we discuss the key theoretical issues which are involved in a
detailed prediction of light nuclide abundances, as the weak reaction rates,
neutrino decoupling and nuclear rate modeling. We also perform a new analysis
of available data on the main nuclear processes entering the nucleosynthesis
reaction network, with particular stress on their uncertainties as well as on
their role in determining the corresponding uncertainties on light nuclide
theoretical estimates. The current status of theoretical versus experimental
results for 2H, 3He, 4He and 7Li is then discussed using the determination of
the baryon density as obtained from Cosmic Microwave Background anisotropies.Comment: LaTeX, 83 pages, 30 .pdf figures. Some typos in the units of
R-functions in appendix D and relative plots fixe
A Radically Configurable Six-State Compound
Most organic radicals possess short lifetimes and quickly undergo dimerization or oxidation.
Here, we report on the synthesis by radical templation of a class of air- and water-stable
organic radicals, trapped within a homo[2]catenane composed of two rigid and fixed cyclobis
(paraquat-p-phenylene) rings. The highly energetic octacationic homo[2]catenane, which is
capable of accepting up to eight electrons, can be configured reversibly, both chemically
and electrochemically, between each one of six experimentally accessible redox states
(0, 2+, 4+, 6+, 7+, and 8+) from within the total of nine states evaluated by quantum
mechanical methods. All six of the observable redox states have been identified by electrochemical
techniques, three (4+, 6+, and 7+) have been characterized by x-ray crystallography, four
(4+, 6+, 7+, and 8+) by electron paramagnetic resonance spectroscopy, one (7+) by
superconducting quantum interference device magnetometry, and one (8+) by nuclear
magnetic resonance spectroscopy
Molecular Russian dolls
The host-guest recognition between two macrocycles to form hierarchical non-intertwined ring-in-ring assemblies remains an interesting and challenging target in noncovalent synthesis. Herein, we report the design and characterization of a box-in-box assembly on the basis of host-guest radical-pairing interactions between two rigid diradical dicationic cyclophanes. One striking feature of the box-in-box complex is its ability to host various 1,4-disubstituted benzene derivatives inside as a third component in the cavity of the smaller of the two diradical dicationic cyclophanes to produce hierarchical Russian doll like assemblies. These results highlight the utility of matching the dimensions of two different cyclophanes as an efficient approach for developing new hybrid supramolecular assemblies with radical-paired ring-in-ring complexes and smaller neutral guest molecules
Primordial Nucleosynthesis for the New Cosmology: Determining Uncertainties and Examining Concordance
Big bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) have
a long history together in the standard cosmology. The general concordance
between the predicted and observed light element abundances provides a direct
probe of the universal baryon density. Recent CMB anisotropy measurements,
particularly the observations performed by the WMAP satellite, examine this
concordance by independently measuring the cosmic baryon density. Key to this
test of concordance is a quantitative understanding of the uncertainties in the
BBN light element abundance predictions. These uncertainties are dominated by
systematic errors in nuclear cross sections. We critically analyze the cross
section data, producing representations that describe this data and its
uncertainties, taking into account the correlations among data, and explicitly
treating the systematic errors between data sets. Using these updated nuclear
inputs, we compute the new BBN abundance predictions, and quantitatively
examine their concordance with observations. Depending on what deuterium
observations are adopted, one gets the following constraints on the baryon
density: OmegaBh^2=0.0229\pm0.0013 or OmegaBh^2 = 0.0216^{+0.0020}_{-0.0021} at
68% confidence, fixing N_{\nu,eff}=3.0. Concerns over systematics in helium and
lithium observations limit the confidence constraints based on this data
provide. With new nuclear cross section data, light element abundance
observations and the ever increasing resolution of the CMB anisotropy, tighter
constraints can be placed on nuclear and particle astrophysics. ABRIDGEDComment: 54 pages, 20 figures, 5 tables v2: reflects PRD version minor changes
to text and reference
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