24 research outputs found
Nondestructive in-line sub-picomolar detection of magnetic nanoparticles in flowing complex fluids
Over the last decades, the use of magnetic nanoparticles in research and
commercial applications has increased dramatically. However, direct detection
of trace quantities remains a challenge in terms of equipment cost, operating
conditions and data acquisition times, especially in flowing conditions within
complex media. Here we present the in-line, non-destructive detection of
magnetic nanoparticles using high performance atomic magnetometers at ambient
conditions in flowing media. We achieve sub-picomolar sensitivities measuring
30 nm ferromagnetic iron and cobalt nanoparticles that are suitable for
biomedical and industrial applications, under flowing conditions in water and
whole blood. Additionally, we demonstrate real-time surveillance of the
magnetic separation of nanoparticles from water and whole blood. Overall our
system has the merit of inline direct measurement of trace quantities of
ferromagnetic nanoparticles with so far unreached sensitivities and could be
applied in the biomedical field (diagnostics and therapeutics) but also in the
industrial sector
Comparing the transcriptomes of embryos from domesticated and wild Atlantic salmon (Salmo salar L.) stocks and examining factors that influence heritability of gene expression
Background Due to selective breeding, domesticated and wild Atlantic salmon are genetically diverged, which raises concerns about farmed escapees having the potential to alter the genetic composition of wild populations and thereby disrupting local adaptation. Documenting transcriptional differences between wild and domesticated stocks under controlled conditions is one way to explore the consequences of domestication and selection. We compared the transcriptomes of wild and domesticated Atlantic salmon embryos, by using a custom 44k oligonucleotide microarray to identify perturbed gene pathways between the two stocks, and to document the inheritance patterns of differentially-expressed genes by examining gene expression in their reciprocal hybrids. Results Data from 24 array interrogations were analysed: four reciprocal cross types (W♀×W♂, D♀×W♂; W♀×D♂, D♀×D♂)×six biological replicates. A common set of 31,491 features on the microarrays passed quality control, of which about 62% were assigned a KEGG Orthology number. A total of 6037 distinct genes were identified for gene-set enrichment/pathway analysis. The most highly enriched functional groups that were perturbed between the two stocks were cellular signalling and immune system, ribosome and RNA transport, and focal adhesion and gap junction pathways, relating to cell communication and cell adhesion molecules. Most transcripts that were differentially expressed between the stocks were governed by additive gene interaction (33 to 42%). Maternal dominance and over-dominance were also prevalent modes of inheritance, with no convincing evidence for a stock effect. Conclusions Our data indicate that even at this relatively early developmental stage, transcriptional differences exist between the two stocks and affect pathways that are relevant to wild versus domesticated environments. Many of the identified differentially perturbed pathways are involved in organogenesis, which is expected to be an active process at the eyed egg stage. The dominant effects are more largely due to the maternal line than to the origin of the stock. This finding is particularly relevant in the context of potential introgression between farmed and wild fish, since female escapees tend to have a higher spawning success rate compared to males
Measuring molecular parity nonconservation using nuclear-magnetic-resonance spectroscopy
Scope
Scope, later retitled Centerscope, was published by the Boston University Medical Center to report on events at and around the Center
Measuring molecular parity nonconservation using nuclear-magnetic-resonance spectroscopy
The weak interaction does not conserve parity and therefore induces energy shifts in chiral enantiomers that should in principle be detectable in molecular spectra. Unfortunately, the magnitude of the expected shifts are small and in spectra of a mixture of enantiomers, the energy shifts are not resolvable. We propose a nuclear-magnetic-resonance (NMR) experiment in which we titrate the chirality (enantiomeric excess) of a solvent and measure the diasteriomeric splitting in the spectra of a chiral solute in order to search for an anomalous offset due to parity nonconservation (PNC). We present a proof-of-principle experiment in which we search for PNC in the 13C resonances of small molecules, and use the 1H resonances, which are insensitive to PNC, as an internal reference. We set a constraint on molecular PNC in 13C chemical shifts at a level of 10−5 ppm, and provide a discussion of important considerations in the search for molecular PNC using NMR spectroscopy