1,119 research outputs found
A multipoint field ionization source Final report, 11 Nov. 1966 - 12 Apr. 1968
Experimental study on use of field ionization and electron emission as ion sources for mass spectrometer
Geographic and seasonal variation of flying squirrel vocalizations in California
Advancements in bioacoustics field studies have further elucidated spatial, temporal, and behavioral aspects of otherwise-cryptic species, as well as offering insights into species communication. The discovery of high-frequency vocalizations in North American flying squirrels in particular has allowed researchers to use ultrasonic acoustic recorders to detect these cryptic species in the wild. Investigations into vocalizations of northern flying squirrels (Glaucomys sabrinus) and southern flying squirrels (G. volans) have highlighted call type variation between species and the potential use of recorders as a tool to examine vocal activity patterns. However, high-frequency vocalizations had yet to be quantitatively analyzed for the recently discovered Humboldt’s flying squirrel (G. oregonensis). Using ultrasonic acoustic recorders, I recorded flying squirrels in Humboldt and San Bernardino counties, California to: 1) measure and compare call properties and call types of Humboldt’s flying squirrels and the San Bernardino subspecies (G. o. californicus) and test for geographic variation, 2) determine the extent of seasonal variation that exists between call type rates, and 3) test for seasonal differences in their nightly vocal activity patterns within and between counties. I hypothesized that variation in call properties may exist between Humboldt’s flying squirrel and the San Bernardino subspecies, and that nightly call rates and vocal activity patterns would differ between summer and winter. I collected over 27,000 calls from 2018-2021 from different areas in Humboldt and San Bernardino counties and identified four previously described call types in flying squirrels: arcs, upsweeps, chirps, and trills. I found significant geographic variation in arc and trill call types when comparing call properties between counties, but these call properties were not significantly different across areas within each county. Additionally, I found that vocal activity patterns were similar between seasons within each county as well as between counties, but I found significant differences in the timing of call types across seasons within both counties. I also demonstrate the usefulness of ultrasonic recorders as a minimally-invasive tool for surveying for flying squirrels and their potential for assisting in future investigations into the behavior, ecology, and conservation of these enigmatic, forest-dwelling species
1861-08-15 A.B. Farwell writes to Governor Washburn regarding open rebellion of the 2nd Regiment troops and urges more attention be paid to their wants
https://digitalmaine.com/cw_me_2nd_regiment_corr/1098/thumbnail.jp
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Preclinical translation of exosomes derived from mesenchymal stem/stromal cells.
Exosomes are nanovesicles secreted by virtually all cells. Exosomes mediate the horizontal transfer of various macromolecules previously believed to be cell-autonomous in nature, including nonsecretory proteins, various classes of RNA, metabolites, and lipid membrane-associated factors. Exosomes derived from mesenchymal stem/stromal cells (MSCs) appear to be particularly beneficial for enhancing recovery in various models of disease. To date, there have been more than 200 preclinical studies of exosome-based therapies in a number of different animal models. Despite a growing number of studies reporting the therapeutic properties of MSC-derived exosomes, their underlying mechanism of action, pharmacokinetics, and scalable manufacturing remain largely outstanding questions. Here, we review the global trends associated with preclinical development of MSC-derived exosome-based therapies, including immunogenicity, source of exosomes, isolation methods, biodistribution, and disease categories tested to date. Although the in vivo data assessing the therapeutic properties of MSC-exosomes published to date are promising, several outstanding questions remain to be answered that warrant further preclinical investigation
Expanding P450 catalytic reaction space through evolution and engineering
Advances in protein and metabolic engineering have led to wider use of enzymes to synthesize important molecules. However, many desirable transformations are not catalyzed by any known enzyme, driving interest in understanding how new enzymes can be created. The cytochrome P450 enzyme family, whose members participate in xenobiotic metabolism and natural products biosynthesis, catalyzes an impressive range of difficult chemical reactions that continues to grow as new enzymes are characterized. Recent work has revealed that P450-derived enzymes can also catalyze useful reactions previously accessible only to synthetic chemistry. The evolution and engineering of these enzymes provides an excellent case study for how to genetically encode new chemistry and expand biology's reaction space
Evaluation of tantalum for mercury containment in the SNAP-8 boiler
Corrosion testing of tantalum for mercury containment in SNAP 8 boile
1861-09-14 N.A. Farwell urges the exchange of muskets for rifles
https://digitalmaine.com/cw_me_4th_regiment_corr/1084/thumbnail.jp
1861-09-02 N.A. Farwell recommends the promotion of Hiram Berry to Brigadier General
https://digitalmaine.com/cw_me_4th_regiment_corr/1075/thumbnail.jp
1862-08-13 N.A. Farwell recommends Orpheus N. Blackington for appointment in a new regiment
https://digitalmaine.com/cw_me_4th_regiment_corr/1246/thumbnail.jp
1861-10-01 N.A. Farwell recommends Samuel C. Lovejoy for position as hospital steward
https://digitalmaine.com/cw_me_1st_cav/1100/thumbnail.jp
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