6 research outputs found
Main Group Redox Catalysis: Reversible P<sup>III</sup>/P<sup>V</sup> Redox Cycling at a Phosphorus Platform
A planar, trivalent phosphorus compound is shown to undergo
reversible
two-electron redox cycling (PIII/PV) enabling
its use as catalyst for a transfer hydrogenation reaction. The trivalent
phosphorus compound activates ammonia-borane to furnish a 10-P-5 dihydridophosphorane,
which in turn is shown to transfer hydrogen cleanly to azobenzene,
yielding diphenylhydrazine and regenerating the initial trivalent
phosphorus species. This result constitutes a rare example of two-electron
redox catalysis at a main group compound and suggests broader potential
for this nonmetal platform to support bond-modifying redox catalysis
of the type dominated by transition metal catalysts
Main Group Redox Catalysis: Reversible P<sup>III</sup>/P<sup>V</sup> Redox Cycling at a Phosphorus Platform
A planar, trivalent phosphorus compound is shown to undergo
reversible
two-electron redox cycling (P<sup>III</sup>/P<sup>V</sup>) enabling
its use as catalyst for a transfer hydrogenation reaction. The trivalent
phosphorus compound activates ammonia-borane to furnish a 10-P-5 dihydridophosphorane,
which in turn is shown to transfer hydrogen cleanly to azobenzene,
yielding diphenylhydrazine and regenerating the initial trivalent
phosphorus species. This result constitutes a rare example of two-electron
redox catalysis at a main group compound and suggests broader potential
for this nonmetal platform to support bond-modifying redox catalysis
of the type dominated by transition metal catalysts
Polysorbate- and DNA-Mediated Synthesis and Strong, Stable, and Tunable Near-Infrared Photoluminescence of Plasmonic Long-Body Nanosnowmen
Direct
photoluminescence (PL) from metal nanoparticles (NPs) without
chemical dyes is promising for sensing and imaging applications since
this offers a highly tunable platform for controlling and enhancing
the signals in various conditions and does not suffer from photobleaching
or photoblinking. It is, however, difficult to synthesize metal NPs
with a high quantum yield (QY), particularly in the near-infrared
(NIR) region where deep penetration and reduced light scattering are
advantageous for bioimaging. Herein, we designed and synthesized Au–Ag
long-body nanosnowman structures (LNSs), facilitated by polysorbate
20 (Tween 20). The DNA-engineered conductive junction between the
head and body parts results in a charge transfer plasmon (CTP) mode
in the NIR region. The junction morphology can be controlled by the
DNA sequence on the Au core, and polythymine and polyadenine induced
thick and thin junctions, respectively. We found that the LNSs with
a thicker conductive junction generates the stronger CTP peak and
PL signal than the LNSs with a thinner junction. The Au–Ag
LNSs showed much higher intensities in both PL and QY than widely
studied Au nanorods with similar localized surface plasmon resonance
wavelengths, and notably, the LNSs displayed high photostability and
robust, sustainable PL signals under continuous laser exposure for
>15 h. Moreover, the PL emission from Au–Ag LNSs could be
imaged
in a deeper scattering medium than fluorescent silica NPs. Finally,
highly robust PL-based cell images can be obtained using Au–Ag
LNSs without significant signal change while repetitively imaging
cells. The results offer the insights in plasmonic NIR probe design,
and show that chemical dye-free LNSs can be a very promising candidate
with a high QY and a robust, reliable NIR PL signal for NIR sensing
and imaging applications
Additional file 1 of Evaluation of the meibomian glands using the tear interferometer wearing orthokeratology lenses
Additional file 1: Table S1. The median and range values for parameters measured by the LipiView® II Ocular Surface Interferometer without (Control group) and with (Ortho-K group) orthokeratologytreatment in Korean children
Immunogenic Extracellular Vesicles Derived from Endoplasmic Reticulum-Stressed Tumor Cells: Implications as the Therapeutic Cancer Vaccine
Tumor-derived
extracellular vesicles (TDEs) have potential for
therapeutic cancer vaccine applications since they innately possess
tumor-associated antigens, mediate antigen presentation, and can incorporate
immune adjuvants for enhanced vaccine efficacy. However, the original
TDEs also contain immune-suppressive proteins. To address this, we
proposed a simple yet powerful preconditioning method to improve the
overall immunogenicity of the TDEs. This approach involved inducing
endoplasmic reticulum (ER) stress on parental tumor cells via N-glycosylation
inhibition with tunicamycin. The generated immunogenic TDEs (iTDEs)
contained down-regulated immunosuppressive proteins and up-regulated
immune adjuvants, effectively activating dendritic cells (DCs) in vitro. Furthermore, in vivo evidence
from a tumor-bearing mouse model showed that iTDEs activated DCs,
enabling cytotoxic T lymphocytes (CTLs) to target tumors, and eventually
established a systemic antitumor immune response. Additionally, iTDEs
significantly delayed tumor recurrence in a postsurgery model compared
with control groups. These findings highlight the immense potential
of our strategy for utilizing TDEs to develop effective cancer vaccines
Bridging Big Data: Procedures for Combining Non-equivalent Cognitive Measures from the ENIGMA Consortium
AbstractInvestigators in the cognitive neurosciences have turned to Big Data to address persistent replication and reliability issues by increasing sample sizes, statistical power, and representativeness of data. While there is tremendous potential to advance science through open data sharing, these efforts unveil a host of new questions about how to integrate data arising from distinct sources and instruments. We focus on the most frequently assessed area of cognition - memory testing - and demonstrate a process for reliable data harmonization across three common measures. We aggregated raw data from 53 studies from around the world which measured at least one of three distinct verbal learning tasks, totaling N = 10,505 healthy and brain-injured individuals. A mega analysis was conducted using empirical bayes harmonization to isolate and remove site effects, followed by linear models which adjusted for common covariates. After corrections, a continuous item response theory (IRT) model estimated each individual subject’s latent verbal learning ability while accounting for item difficulties. Harmonization significantly reduced inter-site variance by 37% while preserving covariate effects. The effects of age, sex, and education on scores were found to be highly consistent across memory tests. IRT methods for equating scores across AVLTs agreed with held-out data of dually-administered tests, and these tools are made available for free online. This work demonstrates that large-scale data sharing and harmonization initiatives can offer opportunities to address reproducibility and integration challenges across the behavioral sciences.Significance StatementData sharing can increase the quality and rigor of scientific claims, but with large scale data sharing comes an increased need to combine non-equivalent measurements across studies. Auditory verbal learning tasks (AVLTs) are one of the most common research and clinical tools to evaluate memory constructs, but numerous distinct AVLTs are in common use, which creates challenges for data aggregation. We report methods to convert raw scores across common verbal learning instruments, constructed using harmonizing data from 53 studies from around the world. This approach can be replicated in other domains to address long standing data compatibility issues for researchers and clinicians
