HPLC is a powerful and popular method for analyzing and purifying biomolecules. Reversed-phase HPLC allows a high-capacity method for purification, and uses volatile buffer systems that simplify ...product recovery. Anion-exchange HPLC provides better resolution and a more predictable elution pattern. This unit presents protocols that are optimized for HPLC of oligonucleotides. Because of the resolution limits of both reversed-phase and anion-exchange HPLC, it can be used for oligonucleotides of up to approximately 50 nt in length.
In this protocol, nuclease digestion of an oligonucleotide is followed by dephosphorylation and HPLC analysis of the monomers on a reversed-phase C18 column. This method can be used to detect and ...quantitate a wide variety of nucleobase modifications in oligonucleotides. Integrated areas of the nucleoside chromatogram give precise quantitation of nucleoside composition when the relative extinction coefficient cofactors are applied to the sum of the areas of the four bases. The protocol is also useful for analysis of oligonucleotides containing conjugated moieties and carbohydrate modifications.
The Hermes experiment has investigated the tensor spin structure of the deuteron using the 27.6 GeV/c positron beam of DESY HERA. The use of a tensor-polarized deuteron gas target with only a ...negligible residual vector polarization enabled the first measurement of the tensor asymmetry A(d)zz and the tensor structure function b(d)1 for average values of the Bjorken variable 0.01< <0.45 and of the negative of the squared four-momentum transfer 0.5 GeV2 < <5 GeV2. The quantities A(d)zz and b(d)1 are found to be nonzero. The rise of b(d)1 for decreasing values of x can be interpreted to originate from the same mechanism that leads to nuclear shadowing in unpolarized scattering.
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Synthetic nucleic acids are produced routinely for a wide variety of applications, including biological and chemical research, and diagnostic or therapeutic applications. To ensure an adequate level ...of quality and purity, rapid and convenient analytical methods are necessary. This unit discusses basic principles to guide in the selection of appropriate purification and analysis protocols.
The purpose of this mixed-methods study was to explore the perceptions of secondary-school band teachers as they moved to virtual formats with their students. The study was designed to fill a gap in ...the literature, as little research has been done on the subject of distance learning and music. As teachers reflect on their pandemic-closed schools, what are their perspectives on the distance-learning process? What do they perceive to be the best practices for virtual instruction? To find answers, this study was guided by the following questions: Do secondary band teachers believe distanced music education can maintain institutional quality and validity? What factors do they believe improve the outcomes of distance applied-music lessons? A parallel mixed-model cross-sectional survey containing a researcher-designed questionnaire was anonymously administered online via Qualtrics to 80 Texas band directors. The data was quantitatively analyzed using Minitab statistical software and qualitatively coded for themes. It emerged that participants felt they were not given training, did not have defined responsibilities, and were not provided clear expectations about teaching band remotely. Feeling unsupported by their administration, they turned to their colleagues, collaborating to learn how to successfully teach music virtually. Participants had largely negative perceptions of distance learning in band, reporting that technical limitations and difficulty playing in ensemble were difficult challenges to meet; in addition, they saw the loss of contact with students as the most negative aspect of switching away from in-person teaching. This study suggests that in its present form, online band instruction is a contradiction in terms (Keegan, 1996).
Protocols are given for purification of oligonucleotides by dimethoxytrityl-sensitive and affinity desalting methods. The protocols are applicable for many of the convenient disposable products ...available for rapid oligonucleotide purification, clean-up by selective adsorption, and elution on solid-phase media. Many of these products are prepackaged, single-use cartridges or columns filled with affinity or size-exclusion media.
Recent large and severe outbreaks of native bark beetles have raised concern among the general public and land managers about potential for amplified fire activity in western North America. To date, ...the majority of studies examining bark beetle outbreaks and subsequent fire severity in the U.S. Rocky Mountains have focused on outbreaks of mountain pine beetle (MPB; Dendroctonus ponderosae) in lodgepole pine (Pinus contorta) forests, but few studies, particularly field studies, have addressed the effects of the severity of spruce beetle (Dendroctonus rufipennis Kirby) infestation on subsequent fire severity in subalpine Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) forests. In Colorado, the annual area infested by spruce beetle outbreaks is rapidly rising, while MPB outbreaks are subsiding; therefore understanding this relationship is of growing importance. We collected extensive field data in subalpine forests in the eastern San Juan Mountains, southwestern Colorado, USA, to investigate whether a grayâstage (<5Â yr from outbreak to time of fire) spruce beetle infestation affected fire severity. Contrary to the expectation that bark beetle infestation alters subsequent fire severity, correlation and multivariate generalized linear regression analysis revealed no influence of preâfire spruce beetle severity on nearly all field or remotely sensed measurements of fire severity. Findings were consistent across moderate and extreme burning conditions. In comparison to severity of the preâfire beetle outbreak, we found that topography, preâoutbreak basal area, and weather conditions exerted a stronger effect on fire severity. Our finding that beetle infestation did not alter fire severity is consistent with previous retrospective studies examining fire activity following other bark beetle outbreaks and reiterates the overriding influence of climate that creates conditions conducive to large, highâseverity fires in the subalpine zone of Colorado. Both bark beetle outbreaks and wildfires have increased autonomously due to recent climate variability, but this study does not support the expectation that postâbeetle outbreak forests will alter fire severity, a result that has important implications for management and policy decisions.
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