Visual Field Location of the Stimulus Modulates Time Perception

Master'sMASTER OF SOCIAL SCIENCE

Hydrophobic Silica Microcavities with Sustainable Nonlinear Photonic Performance

Ultrahigh quality factor (Q) microcavities have been emerging as an appealing compact photonic platform for various applications. The Q factor plays a critical role in determining the nonlinear optical performance of a microcavity. However, a silica microcavity suffers from severe degradation of its Q value over time during storage or use in air due to the accumulating surface absorption loss, which would deteriorate their nonlinear photonic performance. Here, we report a new type of ultrahigh Q silica microcavity that effectively prevents the Q degradation over time. The Q values of the devices remain unchanged over time under storage in air. Optical frequency combs are generated with sustainable ultralow threshold performance in the course of time from the devices in open air. This approach would greatly facilitate ultrahigh Q silica-based photonic devices for next generation photonic applications

Lasing- Encoded Microsensor Driven by Interfacial Cavity Resonance Energy Transfer

Microlasers are emerging tools for biomedical applications. In particular, whispering- gallery- mode (WGM) microlasers are promising candidates for sensing at the biointerface owing to their high quality- factor and potential in molecular assays, and intracellular and extracellular detection. However, lasing particles with sensing functionality remain challenging since the overlap between the WGM optical mode and external gain medium is much lower compared to internal gain inside the cavity. To overcome this problem, the concept of Förster resonant energy transfer (FRET) is exploited on WGM droplet microlaser by separating donor and acceptor molecules at the cavity- surface interface. It is first discovered that the interfacial FRET laser not only originates from conventional FRET but utilizes coherent radiative energy transfer (CRET) to excite acceptor molecules by inducing light- harvesting effect near the cavity interface. Simulations and experiments have revealed that the absorption spectrum of individual analyte plays a crucial role in interfacial FRET laser. Distinct lasing spectra can therefore distinguish molecules of different absorption properties upon binding. Finally, detection of small fluorescent molecules and photosynthetic protein is performed. The results presented here not only demonstrate the wide- ranging potential of microlaser external cavity implementation in molecular sensing applications, but also provide comprehensive insights into cavity energy transfer in laser physics.A novel concept is proposed to achieve active lasing- encoded biosensors by taking advantage of light- harvesting effect at the cavity interface, where interfacial molecular lasers based on cavity resonant energy transfer are demonstrated. This work marks a critical step of realizing whispering- gallery- mode (WGM) laser probes for biosensing, opening a new avenue in laser- based molecular sensing.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154969/1/adom201901596-sup-0001-SuppMat.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154969/2/adom201901596_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154969/3/adom201901596.pd

China–Africa Economic and Trade Cooperation from the Perspective of the Community with Shared Benefits: Achievements, Challenges, and Prospects

The China–Africa Community with Shared Benefits is the cornerstone of the China-Africa Community with Shared Future. Since the beginning of the twenty-first century, through economic and trade cooperation, China and Africa have promoted the common economic and social development of both sides, and consolidated the material foundation of the China–Africa Community with Shared Benefits. The economic and trade cooperation between China and Africa has developed rapidly with remarkable achievements and great influence. This article fully affirms and reviews the great achievements of China–Africa trade and economic cooperation, points out that the China–Africa economic and trade cooperation still faces some challenges, but overall, the China–Africa economic and trade cooperation has an absolutely bright future and will become a persistence engine to build the Community with Shared Benefits. China's investment will further promote economic and social development in Africa, and the China–Africa Community with Shared Benefits will have a huge demonstration effect internationally. </p

Identification of diagnostic biomarkers in Alzheimer’s disease by integrated bioinformatic analysis and machine learning strategies

BackgroundAlzheimer’s disease (AD) is the most prevalent form of dementia, and is becoming one of the most burdening and lethal diseases. More useful biomarkers for diagnosing AD and reflecting the disease progression are in need and of significance.MethodsThe integrated bioinformatic analysis combined with machine-learning strategies was applied for exploring crucial functional pathways and identifying diagnostic biomarkers of AD. Four datasets (GSE5281, GSE131617, GSE48350, and GSE84422) with samples of AD frontal cortex are integrated as experimental datasets, and another two datasets (GSE33000 and GSE44772) with samples of AD frontal cortex were used to perform validation analyses. Functional Correlation enrichment analyses were conducted based on Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and the Reactome database to reveal AD-associated biological functions and key pathways. Four models were employed to screen the potential diagnostic biomarkers, including one bioinformatic analysis of Weighted gene co-expression network analysis (WGCNA)and three machine-learning algorithms: Least absolute shrinkage and selection operator (LASSO), support vector machine-recursive feature elimination (SVM-RFE) and random forest (RF) analysis. The correlation analysis was performed to explore the correlation between the identified biomarkers with CDR scores and Braak staging.ResultsThe pathways of the immune response and oxidative stress were identified as playing a crucial role during AD. Thioredoxin interacting protein (TXNIP), early growth response 1 (EGR1), and insulin-like growth factor binding protein 5 (IGFBP5) were screened as diagnostic markers of AD. The diagnostic efficacy of TXNIP, EGR1, and IGFBP5 was validated with corresponding AUCs of 0.857, 0.888, and 0.856 in dataset GSE33000, 0.867, 0.909, and 0.841 in dataset GSE44770. And the AUCs of the combination of these three biomarkers as a diagnostic tool for AD were 0.954 and 0.938 in the two verification datasets.ConclusionThe pathways of immune response and oxidative stress can play a crucial role in the pathogenesis of AD. TXNIP, EGR1, and IGFBP5 are useful biomarkers for diagnosing AD and their mRNA level may reflect the development of the disease by correlation with the CDR scores and Breaking staging

Stimulated and spontaneous optical generation of electron spin coherence in charged GaAs quantum dots

We report on the coherent optical excitation of electron spin polarization in the ground state of charged GaAs quantum dots via an intermediate charged exciton (trion) state. Coherent optical fields are used for the creation and detection of the Raman spin coherence between the spin ground states of the charged quantum dot. The measured spin decoherence time, which is likely limited by the nature of the spin ensemble, approaches 10 ns at zero field. We also show that the Raman spin coherence in the quantum beats is caused not only by the usual stimulated Raman interaction but also by simultaneous spontaneous radiative decay of either excited trion state to a coherent combination of the two spin states.Comment: 4 pages, 3 figures. Minor modification