758 research outputs found
Preclinical Applications of 3'-Deoxy-3'-[18F]Fluorothymidine in Oncology - A Systematic Review
The positron emission tomography (PET) tracer 3'-deoxy-3'-[18F]fluorothymidine ([18F]FLT) has been proposed to measure cell proliferation non-invasively in vivo. Hence, it should provide valuable information for response assessment to tumor therapies. To date, [18F]FLT uptake has found limited use as a response biomarker in clinical trials in part because a better understanding is needed of the determinants of [18F]FLT uptake and therapy-induced changes of its retention in the tumor. In this systematic review of preclinical [18F]FLT studies, comprising 174 reports, we identify the factors governing [18F]FLT uptake in tumors, among which thymidine kinase 1 plays a primary role. The majority of publications (83 %) report that decreased [18F]FLT uptake reflects the effects of anticancer therapies. 144 times [18F]FLT uptake was related to changes in proliferation as determined by ex vivo analyses. Of these approaches, 77 % describe a positive relation, implying a good concordance of tracer accumulation and tumor biology. These preclinical data indicate that [18F]FLT uptake holds promise as an imaging biomarker for response assessment in clinical studies. Understanding of the parameters which influence cellular [18F]FLT uptake and retention as well as the mechanism of changes induced by therapy is essential for successful implementation of this PET tracer. Hence, our systematic review provides the background for the use of [18F]FLT in future clinical studies
Measurement of proton electromagnetic form factors in in the energy region 2.00-3.08 GeV
The process of is studied at 22 center-of-mass
energy points () from 2.00 to 3.08 GeV, exploiting 688.5~pb of
data collected with the BESIII detector operating at the BEPCII collider. The
Born cross section~() of is
measured with the energy-scan technique and it is found to be consistent with
previously published data, but with much improved accuracy. In addition, the
electromagnetic form-factor ratio () and the value of the
effective (), electric () and magnetic () form
factors are measured by studying the helicity angle of the proton at 16
center-of-mass energy points. and are determined with
high accuracy, providing uncertainties comparable to data in the space-like
region, and is measured for the first time. We reach unprecedented
accuracy, and precision results in the time-like region provide information to
improve our understanding of the proton inner structure and to test theoretical
models which depend on non-perturbative Quantum Chromodynamics
Search for the decay
We search for radiative decays into a weakly interacting neutral
particle, namely an invisible particle, using the produced through the
process in a data sample of
decays collected by the BESIII detector
at BEPCII. No significant signal is observed. Using a modified frequentist
method, upper limits on the branching fractions are set under different
assumptions of invisible particle masses up to 1.2 . The upper limit corresponding to an invisible particle with zero mass
is 7.0 at the 90\% confidence level
First observations of hadrons
Based on events collected with
the BESIII detector, five hadronic decays are searched for via process
. Three of them, ,
, and are observed for the first
time, with statistical significances of 7.4, , and
9.1, and branching fractions of ,
, and ,
respectively, where the first uncertainties are statistical and the second
systematic. No significant signal is observed for the other two decay modes,
and the corresponding upper limits of the branching fractions are determined to
be and at 90% confidence level.Comment: 17 pages, 16 figure
Precise Measurements of Branching Fractions for Meson Decays to Two Pseudoscalar Mesons
We measure the branching fractions for seven two-body decays to
pseudo-scalar mesons, by analyzing data collected at
GeV with the BESIII detector at the BEPCII collider. The branching fractions
are determined to be ,
,
,
,
,
,
,
where the first uncertainties are statistical, the second are systematic, and
the third are from external input branching fraction of the normalization mode
. Precision of our measurements is significantly improved
compared with that of the current world average values
Meningeal lymphatic endothelial cells fulfill scavenger endothelial cell function and cooperate with microglia in waste removal from the brain
Brain lymphatic endothelial cells (BLECs) constitute a group of loosely connected endothelial cells that reside within the meningeal layer of the zebrafish brain without forming a vascular tubular system. BLECs have been shown to readily endocytose extracellular cargo molecules from the brain parenchyma, however, their functional relevance in relation to microglia remains enigmatic. We here compare their functional uptake efficiency for several macromolecules and bacterial components with microglia in a qualitative and quantitative manner in 5-day-old zebrafish embryos. We find BLECs to be significantly more effective in the uptake of proteins, polysaccharides and virus particles as compared to microglia, while larger particles like bacteria are only ingested by microglia but not by BLECs, implying a clear distribution of tasks between the two cell types in the brain area. In addition, we compare BLECs to the recently discovered scavenger endothelial cells (SECs) of the cardinal vein and find them to accept an identical set of substrate molecules. Our data identifies BLECs as the first brain-associated SEC population in vertebrates, and demonstrates that BLECs cooperate with microglia to remove particle waste from the brain.Thrombosis and Hemostasi
Improved measurements of the absolute branching fractions of the inclusive decays D+ (0) →φX
By analyzing 2.93 fb-1 of e+e- annihilation data taken at the center-of-mass energy s=3.773 GeV with the BESIII detector, we determine the branching fractions of the inclusive decays D+→φX and D0→φX to be (1.135±0.034±0.031)% and (1.091±0.027±0.035)%, respectively, where X denotes any possible particle combination. The first uncertainties are statistical, and the second are systematic. We also determine the branching fractions of the decays D→φX and their charge conjugate modes D→φX separately for the first time, and no significant CP asymmetry is observed
Search for an invisible muon philic scalar or vector via decay at BESIII
A light scalar or vector particles have been introduced as a
possible explanation for the anomaly and dark matter phenomena.
Using \jpsi events collected by the BESIII
detector, we search for a light muon philic scalar or vector in
the processes with invisible decays. No
obvious signal is found, and the upper limits on the coupling
between the muon and the particles are set to be between
and for the mass in the range
of ~MeV at 90 confidence level.Comment: 9 pages 7 figure
Study of the Decays and
Using an annihilation data sample corresponding to an integrated
luminosity of and collected at a center-of-mass energy
with the BESIII detector, we measure the
absolute branching fractions and . The branching fraction of is
compatible with the world average and that of is measured for the first time. We present the first
measurement of the - asymmetry in the decays , and . In addition,
we measure the direct asymmetries and
- …