778 research outputs found
Maintenance of head and neck tumor on-chip: gateway to personalized treatment?
Aim: Head and neck squamous cell carcinomas (HNSCC) are solid tumors with low overall survival (40–60%). In a move toward personalized medicine, maintenance of tumor biopsies in microfluidic tissue culture devices is being developed. Methodology/ results: HNSCC (n = 15) was dissected (5–10 mg) and either analyzed immediately or cultured in a microfluidic device (37°C) for 48 h. No difference was observed in morphology between pre- and postculture specimens. Dissociated samples were analyzed using trypan blue exclusion (viability), propidium iodide flow cytometry (death) and MTS assay (proliferation) with no significant difference observed highlighting tissue maintenance. Computational fluid dynamics showed laminar flow within the system. Conclusion: The microfluidic culture system successfully maintained HNSCC for 48 h, the culture system will allow testing of different treatment modalities with response monitoring. Lay abstract: Head and neck cancers often have a poor treatment outcome. In order to study the response of the tissue, a miniaturized culture system has been developed to keep a small piece of tumor alive. In the current study, we show that small pieces of cancer tissue can be maintained in the system, using tissue structure and viability of single cells as a guide. In future work, patient equivalent treatments can be applied to these microculture systems to investigate individual patient tumor responses, which could help to guide treatment selection
Dichotomous mechanistic behaviour in Narasaka-Heck cyclizations: electron rich Pd-catalysts generate iminyl radicals
Pd-catalyzed cyclizations of oxime esters with pendant alkenes undergo ligand controlled mechanistic divergence. Electron deficient phosphines promote aza-Heck cyclization; electron rich systems favour a SET pathway. Mechanistic experiments differentiate the two manifolds.</p
Is Same-Gender Mentorship Important for Division III Female College Athletes?: An Application of the Mentor Role Theory
In the last twenty years, opportunities for women in intercollegiate athletics have grown exponentially. Unfortunately, women still represent a small number of head coaches in intercollegiate athletics, creating a disparity in numbers between female college athletes and female head coaches. This disparity has led to an imbalance for female college athletes searching for female role models and mentors. This study investigated the mentoring experiences of NCAA Division III female college athletes based on their lived experiences with both male and female head coaches. Using Mentor Role Theory (MRT), a set of qualitative responses were collected and analyzed. The participants highlighted career and psychosocial functions of MRT, with responses emphasizing positive and negative experiences with their past and present head coaches. Overall, female college athletes noted the importance of both career and psychosocial functions in their experiences with both male and female coaches. However, the college athletes’ experiences with their female head coaches were predominately positive, whereas, the participants were found to hold mixed experiences (both positive and negative) with their male coaches. The authors discuss the implications of these findings for Division III athletics, mentor role theory, and the importance of the coach/athlete relationship
Enantioselective Narasaka-Heck Cyclizations:Synthesis of Tetrasubstituted Nitrogen-Bearing Stereocenters
A SPINOL-derived P,N-ligand system enables Pd-catalyzed 5-exo cyclization of oxime esters with trisubstituted alkenes to generate dihydropyrroles in up to 86% yield and 95 : 5 e.r.</p
Recent developments in the use of aza-Heck cyclizations for the synthesis of chiral N-heterocycles
The scope and mechanism of aza-Heck methodologies that provide chiral heterocyclic systems are outlined.</p
Copper catalyzed Heck-like cyclizations of oxime esters
Copper catalyzed Heck-like cyclizations of oxime esters are described. This new protocol is an effective alternative to Pd-based systems and highlights the value of replacing precious metal catalysts with cheaper and more sustainable variants.</p
The X-ray Properties of Optically-Selected Galaxy Clusters
We stacked the X-ray data from the ROSAT All Sky Survey for over 4,000
clusters selected from the 2MASS catalog and divided into five richness
classes. We detected excess X-ray emission over background at the center of the
stacked images in all five richness bins. The interrelationships between the
mass, X-ray temperature and X-ray luminosity of the stacked clusters agree well
with those derived from catalogs of X-ray clusters. Poisson variance in the
number of galaxies occupying halos of a given mass leads to significant
differences between the average richness at fixed mass and the average mass at
fixed richness that we can model relatively easily using a simple model of the
halo occupation distribution. These statistical effects probably explain recent
results in which optically-selected clusters lie on the same X-ray
luminosity-temperature relations as local clusters but have lower optical
richnesses than observed for local clusters with the same X-ray properties.
When we further binned the clusters by redshift, we did not find significant
redshift-dependent biases in the sense that the X-ray luminosities for massive
clusters of fixed optical richness show little dependence on redshift beyond
that expected from the effects of Poisson fluctuations. Our results demonstrate
that stacking of RASS data from optically selected clusters can be a powerful
test for biases in cluster selection algorithms.Comment: 35 pages, 14 figures, Accepted by ApJ, with updated Lx normalizatio
Web Archiving Democracy
Mary Haberle is a Web Archivist at Archive-It, which is the Internet Archive’s subscription web archiving service. She's part of a support team that provides training and direct support services to our partners, including the archivists on this panel who are all using Archive-It at their institutions.
Dory Bower has been an Archives Specialist at the U.S. Government Publishing Office since 2010, where she has worked on a number of projects to increase access to electronic U.S. government resources. Dory began working with web archiving in 2011 and has played a key role in all aspects of the Federal Depository Library Program Web Archive.
Megan Craynon has worked at the Maryland State Archives since 2011, and has spent the majority of that time as a team member on the web archiving project. She currently serves as the Deputy Director of Special Collections.
Ben Goldman is the Kalin Librarian for Technological Innovations at Penn State University Libraries, where he has overseen web archiving efforts since 2012.
Roger Christman is the Governors’ Records Archivist at the Library of Virginia. In his spare time, he also manages the Library’s web archiving program.
Nicholas Worby is the Government Information and Statistics Librarian as well as the Web Archives Program Coordinator at the University of Toronto.
Ian Milligan is an associate professor of digital and Canadian history at the University of Waterloo. He’s leading a Mellon-funded project to develop a cloud-based infrastructure for the analysis of web archives.As repositories of primary source materials, archives play a central role in supporting the democratic principles of transparency and accountability. Political discourse and many official records of government have shifted from analog to web-based delivery. Web archiving programs that collect content created by elected officials and governments are vital to a robust civil society, which is central to a healthy democracy.
This panel brings together information professionals and a digital historian engaged with related content. Professionals actively acquiring websites of elected officials and online government publications will discuss why and how their institutions are building web archives in these areas and what gaps, if any, exist. Panelists will offer their perspectives on the current state of researcher access and how archives can better support researcher engagement with web archives. Questions of professional and institutional responsibility as citizens and as employees of democratic institutions will be explored
TADPOL: A 1.3 mm Survey of Dust Polarization in Star-forming Cores and Regions
We present {\lambda}1.3 mm CARMA observations of dust polarization toward 30
star-forming cores and 8 star-forming regions from the TADPOL survey. We show
maps of all sources, and compare the ~2.5" resolution TADPOL maps with ~20"
resolution polarization maps from single-dish submillimeter telescopes. Here we
do not attempt to interpret the detailed B-field morphology of each object.
Rather, we use average B-field orientations to derive conclusions in a
statistical sense from the ensemble of sources, bearing in mind that these
average orientations can be quite uncertain. We discuss three main findings:
(1) A subset of the sources have consistent magnetic field (B-field)
orientations between large (~20") and small (~2.5") scales. Those same sources
also tend to have higher fractional polarizations than the sources with
inconsistent large-to-small-scale fields. We interpret this to mean that in at
least some cases B-fields play a role in regulating the infall of material all
the way down to the ~1000 AU scales of protostellar envelopes. (2) Outflows
appear to be randomly aligned with B-fields; although, in sources with low
polarization fractions there is a hint that outflows are preferentially
perpendicular to small-scale B-fields, which suggests that in these sources the
fields have been wrapped up by envelope rotation. (3) Finally, even at ~2.5"
resolution we see the so-called "polarization hole" effect, where the
fractional polarization drops significantly near the total intensity peak. All
data are publicly available in the electronic edition of this article.Comment: 53 pages, 37 figures -- main body (13 pp., 3 figures), source maps
(32 pp., 34 figures), source descriptions (8 pp.). Accepted by the
Astrophysical Journal Supplemen
Misalignment of magnetic fields and outflows in protostellar cores
We present results of λ1.3 mm dust-polarization observations toward 16 nearby, low-mass protostars, mapped with ∼2.″5 resolution at CARMA. The results show that magnetic fields in protostellar cores on scales of ∼1000 AU are not tightly aligned with outflows from the protostars. Rather, the data are consistent with scenarios where outflows and magnetic fields are preferentially misaligned (perpendicular), or where they are randomly aligned. If one assumes that outflows emerge along the rotation axes of circumstellar disks, and that the outflows have not disrupted the fields in the surrounding material, then our results imply that the disks are not aligned with the fields in the cores from which they forme
- …