221 research outputs found
Statistical Tests for Replacing Human Decision Makers with Algorithms
This paper proposes a statistical framework with which artificial
intelligence can improve human decision making. The performance of each human
decision maker is first benchmarked against machine predictions; we then
replace the decisions made by a subset of the decision makers with the
recommendation from the proposed artificial intelligence algorithm. Using a
large nationwide dataset of pregnancy outcomes and doctor diagnoses from
prepregnancy checkups of reproductive age couples, we experimented with both a
heuristic frequentist approach and a Bayesian posterior loss function approach
with an application to abnormal birth detection. We find that our algorithm on
a test dataset results in a higher overall true positive rate and a lower false
positive rate than the diagnoses made by doctors only. We also find that the
diagnoses of doctors from rural areas are more frequently replaceable,
suggesting that artificial intelligence assisted decision making tends to
improve precision more in less developed regions.Comment: 65 pages, 19 figure
Distance measurements via the morphogen gradient of Bicoid in Drosophila embryos
<p>Abstract</p> <p>Background</p> <p>Patterning along the anterior-posterior (A-P) axis in <it>Drosophila </it>embryos is instructed by the morphogen gradient of Bicoid (Bcd). Despite extensive studies of this morphogen, how embryo geometry may affect gradient formation and target responses has not been investigated experimentally.</p> <p>Results</p> <p>In this report, we systematically compare the Bcd gradient profiles and its target expression patterns on the dorsal and ventral sides of the embryo. Our results support a hypothesis that proper distance measurement and the encoded positional information of the Bcd gradient are along the perimeter of the embryo. Our results also reveal that the dorsal and ventral sides of the embryo have a fundamentally similar relationship between Bcd and its target Hunchback (Hb), suggesting that Hb expression properties on the two sides of the embryo can be directly traced to Bcd gradient properties. Our 3-D simulation studies show that a curvature difference between the two sides of an embryo is sufficient to generate Bcd gradient properties that are consistent with experimental observations.</p> <p>Conclusions</p> <p>The findings described in this report provide a first quantitative, experimental evaluation of embryo geometry on Bcd gradient formation and target responses. They demonstrate that the physical features of an embryo, such as its shape, are integral to how pattern is formed.</p
Controllable Entanglement Distribution Network Based on Silicon Quantum Photonics
The entanglement distribution network connects remote users through sharing
entanglement resources, which is essential for realizing quantum internet. We
proposed a controllable entanglement distribution network (c-EDN) based on a
silicon quantum photonic chip. The entanglement resources were generated by a
quantum light source array based on spontaneous four-wave mixing (SFWM) in
silicon waveguides and distributed to different users through time-reversed
Hong-Ou-Mandel interferences in on-chip Mach-Zehnder interferometers with
thermal phase shifters. A chip sample was designed and fabricated, supporting a
c-EDN with 3 subnets and 24 users. The network topology of entanglement
distributions could be reconfigured in three network states by controlling the
quantum interferences through the phase shifters, which was demonstrated
experimentally. Furthermore, a reconfigurable entanglement-based QKD network
was realized as an application of the c-EDN. The reconfigurable network
topology makes the c-EDN suitable for future quantum networks requiring
complicated network control and management. Moreover, it is also shows that
silicon quantum photonic chips have great potential for large-scale c-EDN,
thanks to their capacities on generating and manipulating plenty of
entanglement resources
Endoplasmic Reticulum Targeting Ratiometric Fluorescent Probe for Carboxylesterase 2 Detection in Drug-Induced Acute Liver Injury
Carboxylesterase 2 (CES2), an endoplasmic reticulum (ER) located phase I enzyme, plays a vital role in the metabolism of various endogenous and exogenous substances, and is regarded as an important target for the design of prodrugs. Unfortunately, superior highly selective ER targeting fluorescent probes for monitoring of CES2 are not currently available. Herein, we report an ER targeting CES2 selective and sensitive ratiometric fluorescent probe ERNB based on the ER localizing group p-toluenesulfonamide. ERNB possessed high specificity, sensitivity, and exhibited excellent subcellular localization when compared to commercial ER tracker, and was used to image CES2 in the ER of living cells. Additionally, using ERNB we evaluated the CES2 regulation under d,l-dithiothreitol and tunicamycin-induced ER stress. Furthermore, we determined the down regulation of CES2 activity and expression in the acetaminophen-induced acute liver injury model. On the basis of these results, we conclude that ERNB is a promising tool for highlighting the role of CES2 in the ER and in exploring the role of CES2 in the development of diseases associated with ER stress.</p
Endoplasmic Reticulum Targeting Ratiometric Fluorescent Probe for Carboxylesterase 2 Detection in Drug-Induced Acute Liver Injury
Carboxylesterase 2 (CES2), an endoplasmic reticulum (ER) located phase I enzyme, plays a vital role in the metabolism of various endogenous and exogenous substances, and is regarded as an important target for the design of prodrugs. Unfortunately, superior highly selective ER targeting fluorescent probes for monitoring of CES2 are not currently available. Herein, we report an ER targeting CES2 selective and sensitive ratiometric fluorescent probe ERNB based on the ER localizing group p-toluenesulfonamide. ERNB possessed high specificity, sensitivity, and exhibited excellent subcellular localization when compared to commercial ER tracker, and was used to image CES2 in the ER of living cells. Additionally, using ERNB we evaluated the CES2 regulation under d,l-dithiothreitol and tunicamycin-induced ER stress. Furthermore, we determined the down regulation of CES2 activity and expression in the acetaminophen-induced acute liver injury model. On the basis of these results, we conclude that ERNB is a promising tool for highlighting the role of CES2 in the ER and in exploring the role of CES2 in the development of diseases associated with ER stress.</p
A photon counting reconstructive spectrometer combining metasurfaces and superconducting nanowire single-photon detectors
Faint light spectroscopy has many important applications such as fluorescence
spectroscopy, lidar and astronomical observations. However, long measurement
time limit its application on real-time measurement. In this work, a photon
counting reconstructive spectrometer combining metasurfaces and superconducting
nanowire single photon detectors (SNSPDs) was proposed. A prototype device was
fabricated on a silicon on isolator (SOI) substrate, and its performance was
characterized. Experiment results show that this device support spectral
reconstruction of mono-color lights with a resolution of 2 nm in the wavelength
region of 1500 nm ~ 1600 nm. The detection efficiency of this device is 1.4% ~
3.2% in this wavelength region. The measurement time required by this photon
counting reconstructive spectrometer was also investigated experimentally,
showing its potential to be applied in the scenarios requiring real-time
measurement
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