12,033 research outputs found
Single-nucleotide polymorphisms: analysis by mass spectrometry
Matrix-assisted laser desorption-ionization (MALDI) mass spectrometry has evolved as a powerful method for analyzing nucleic acids. Here we provide protocols for genotyping single-nucleotide polymorphisms (SNPs) by MALDI based on PCR and primer extension to generate allele-specific products. Furthermore, we present three different approaches for sample preparation of primer-extension products before MALDI analysis and discuss their potential areas of application. The first approach, the 'GOOD' assay, is a purification-free procedure that uses DNA-modification chemistry, including alkylation of phosphorothioate linkages in the extension primers. The other two approaches use either solid-phase extraction or microarray purification for the purification of primer-extension products. Depending on the reaction steps of the various approaches, the protocols take about 6–8 hours
Energy transfer calculations for two C-phycocyanins based on refined x-ray crystal structure coordinates of chromophores
ASTP chemical and microbiological analysis of potable water
The Apollo-Soyuz Test Project procedures for potable water system servicing and the results of preflight and postflight chemical and microbiological analyses of the water are discussed. Tables show results of the analyses. The effectiveness of the water system is evaluated
Access, accountability, and advocacy: culturally and linguistically diverse families’ participation in IEP meetings
All parents of eligible students with disabilities have the right to collaborate as equal members of educational teams developing their children’s Individualized Education Programs (IEP). However, culturally and linguistically diverse families typically experience barriers to collaboration with school professionals. In this paper, we describe findings from four focus group interviews with Chinese, Vietnamese, and Haitian immigrants examining their participation and language access in their children’s IEP meetings, as well as their perspectives on what would improve their IEP meetings. Findings revealed that meaningful engagement was hampered by families’ limited access to information, educators’ lack of accountability, and limited opportunities for families to develop as advocates. Implications of the research addressing the within-meeting and between-meeting barriers are discussed.Accepted manuscrip
A Wireless Double Planar Coil Sensor Arrangement for Monitoring Capacitance Changes Due to Water Uptake Embedded in a Thin Fiber-reinforced Composite
AbstractA wireless, near-field coupled sensor based on two planar spiral coils embedded in a thin fiber-reinforced composite material is presented. The measurement effect exploits the fact that penetrating water changes the effective dielectric permittivity in the volume surrounding the planar coils. This leads to an increase of the sensor self-capacitance and to a decrease of the sensor self-resonant frequency. The sensor targets applications in which non tactile, in-situ monitoring of water uptake, within a confined volume of material, is of interest. In order to describe the general electric behavior a circuit model, considering the sensor and an inductively coupled detection coil, has been developed and verified. An analytic expression for the resonance frequency was deduced. Sensor prototypes were integrated in a glass fiber polypropylene composite. Applied measurements demonstrate the resonance frequency change due to water entering and leaving the material during immersion and drying tests
Vibrational branching ratios and hyperfine structure of BH and its suitability for laser cooling
The simple structure of the BH molecule makes it an excellent candidate for
direct laser cooling. We measure the branching ratios for the decay of the
state to vibrational levels of the ground state, , and find that they are exceedingly favourable for laser
cooling. We verify that the branching ratio for the spin-forbidden transition
to the intermediate state is inconsequentially small. We
measure the frequency of the lowest rotational transition of the X state, and
the hyperfine structure in the relevant levels of both the X and A states, and
determine the nuclear electric quadrupole and magnetic dipole coupling
constants. Our results show that, with a relatively simple laser cooling
scheme, a Zeeman slower and magneto-optical trap can be used to cool, slow and
trap BH molecules.Comment: 7 pages, 5 figures. Updated analysis of A state hyperfine structure
and other minor revision
Franck-Condon Factors and Radiative Lifetime of the A^{2}\Pi_{1/2} - X^{2}\Sigma^{+} Transition of Ytterbium Monoflouride, YbF
The fluorescence spectrum resulting from laser excitation of the
A^{2}\Pi_{1/2} - X^{2}\Sigma^{+} (0,0) band of ytterbium monofluoride, YbF, has
been recorded and analyzed to determine the Franck-Condon factors. The measured
values are compared with those predicted from Rydberg-Klein-Rees (RKR)
potential energy curves. From the fluorescence decay curve the radiative
lifetime of the A^{2}\Pi_{1/2} state is measured to be 28\pm2 ns, and the
corresponding transition dipole moment is 4.39\pm0.16 D. The implications for
laser cooling YbF are discussed.Comment: 5 pages, 5 figure
Quality requirements for reclaimed/recycled water
Water used during current and previous space missions has been either carried or made aloft. Future human space endeavors will require some form of water reclamation and recycling. There is little experience in the U.S. space program with this technology. Water reclamation and recycling constitute engineering challenges of the broadest nature that will require an intensive research and development effort if this technology is to mature in time for practical use on the proposed U.S. Space Station. In order for this to happen, reclaimed/recycled water specifications will need to be devised to guide engineering development. Present NASA Potable Water Specifications are not applicable to reclaimed or recycled water. Adequate specifications for ensuring the quality of the reclaimed or recycled potable water system is reviewed, limitations of present water specifications are examined, world experience with potable water reclamation/recycling systems and systems analogs is reviewed, and an approach to developing pertinent biomedical water specifications for spacecraft is presented. Space Station water specifications should be designed to ensure the health of all likely spacecraft inhabitants including man, animals, and plants
- …