To understand decision-making behavior in simple, controlled environments, Bayesian models are often useful. First, optimal behavior is always Bayesian. Second, even when behavior deviates from ...optimality, the Bayesian approach offers candidate models to account for suboptimalities. Third, a realist interpretation of Bayesian models opens the door to studying the neural representation of uncertainty. In this tutorial, we review the principles of Bayesian models of decision making and then focus on five case studies with exercises. We conclude with reflections and future directions.
In this primer, Ma presents the basics of Bayesian models of decision making, with an emphasis on perception. The paper contains examples, exercises, and solutions to exercises.
The current outbreak of viral pneumonia in the city of Wuhan, China, was caused by a novel coronavirus designated 2019‐nCoV by the World Health Organization, as determined by sequencing the viral RNA ...genome. Many initial patients were exposed to wildlife animals at the Huanan seafood wholesale market, where poultry, snake, bats, and other farm animals were also sold. To investigate possible virus reservoir, we have carried out comprehensive sequence analysis and comparison in conjunction with relative synonymous codon usage (RSCU) bias among different animal species based on the 2019‐nCoV sequence. Results obtained from our analyses suggest that the 2019‐nCoV may appear to be a recombinant virus between the bat coronavirus and an origin‐unknown coronavirus. The recombination may occurred within the viral spike glycoprotein, which recognizes a cell surface receptor. Additionally, our findings suggest that 2019‐nCoV has most similar genetic information with bat coronovirus and most similar codon usage bias with snake. Taken together, our results suggest that homologous recombination may occur and contribute to the 2019‐nCoV cross‐species transmission.
Research Highlights
Taken together, our results suggest that homologous recombination may occur and contribute to the 2019‐nCoV cross‐species transmission.
Colorectal cancer (CRC) remains the most common gastrointestinal cancer and a leading cause of cancer deaths worldwide, with most showing pathologies indicating the malignant transformation of early ...stage intestinal stem cells. The long non-coding RNA Meg3, which functions as a tumor suppressor, has been reported to be abnormal in multiple tumorigenesis events; however, the underlying mechanism by which Meg3 contributes to the malignant proliferation of colonic stem cells remains unclear.
We analyzed the expression levels of Meg3, miR-708, and SOCS3 in samples from Apc loss-of-function (Apc
) mice and patients with CRC, particularly in colonic crypt cells. Apc
mice and AMO/DSS-induced mice model (in vivo) and organoid culture system (in vitro) were used to explore the effect of the Meg3/miR-708/SOCS3 axis on tumorigenesis in the colon. In vitro, we performed RNApull-down, RNA immunoprecipitation, and luciferase reporter assays using DLD1 and RKO cell lines.
The Meg3/miR-708/SOCS3 signaling axis plays a critical role in the early stage of CRC development. Our data showed Meg3 levels negatively correlate with miR-708 levels both in clinical samples and in the Apc
mouse model, which indicated that Meg3 acts as a competitive endogenous RNA (ceRNA) of miR-708. Then, miR-708 served as an oncogene, inducing neoplasia in both Apc
mice and cultured colonic organoids. Put together, miR-708 appears to promote malignant proliferation of colonic stem cells by targeting SOCS3/STAT3 signaling.
These data revealed that Meg3 sponges miR-708 to inhibit CRC development via SOCS3-mediated repression of the malignant proliferation of colonic stem cells. The Meg3/miR-708/SOCS3 signaling axis provides potential targets for the diagnosis and treatment of CRC, particularly early stage CRC.
A nickel‐catalyzed three‐component reaction for the synthesis of difluoroalkylated compounds through tandem difluoroalkylation‐arylation of enamides has been developed. The reaction tolerates a ...variety of arylboronic acids and widely available difluoroalkyl bromides, and even the relatively inert substrate chlorodifluoroacetate. The significant advantages of this protocol are the low‐cost nickel catalyst, synthetic convenience, excellent functional‐group compatibility and high reaction efficiency.
All about efficiency: The title reaction tolerates a variety of arylboronic acids and widely available difluoroalkyl bromides, and even the relatively inert substrate chlorodifluoroacetate. The protocol provides a highly efficient method for the catalytic synthesis of difluoroalkylated compounds.
Carbon dots (CDs) have tremendous potential applications in bioimaging, biomedicine, and optoelectronics. By far, it is still difficult to produce photoluminescence (PL) tunable CDs with high quantum ...yield (QY) across the entire visible spectrum and narrow the emission peak widths of CDs close to those of typical quantum dots. In this work, a series of CDs with tunable emission from 443 to 745 nm, quantum yield within 13–54%, and narrowed full width at half maximum (FWHM) from 108 to 55 nm, are obtained by only adjusting the reaction solvents in a one‐pot solvothermal route. The distinct optical features of these CDs are based on their differences in the particle size, and the content of graphitic nitrogen and oxygen‐containing functional groups, which can be modulated by controlling the dehydration and carbonization processes during solvothermal reactions. Blue, green, yellow, red, and even pure white light emitting films (Commission Internationale de L'Eclairage (CIE)= 0.33, 0.33, QY = 39%) are prepared by dispersing one or three kinds of CDs into polyvinyl alcohol with appropriate ratios. The near‐infrared emissive CDs are excellent fluorescent probes for both in vitro and in vivo bioimaging because of their high QY in water, long‐term stability, and low cytotoxicity.
A solvent‐engineered approach to obtain photoluminescent carbon dots (CDs) with tunable emission from 443 to 745 nm, quantum yield within 13–54%, and narrowed full width at half maximum from 108 to 55 nm is reported. The resulting CDs can be potentially applied in the fabrication of full‐color light‐emitting films and in bioimaging both in vitro and in vivo.
The copper‐catalyzed stereoselective defluorinative borylation and silylation of gem‐difluoroalkenes was developed. The protocol led to the exclusive formation of Z type monofluoroalkenyl borons and ...silanes in generally good efficiency with broad substrate scope. The products formed could be readily transformed to other F‐containing molecules by taking advantage of the versatile reactivities of C−B and C−Si bonds. Experimental and theoretical mechanistic studies were conducted which support an olefin insertion/syn‐planar β‐F elimination pathway.
Facile fabrication of advanced electrode material is highly desired for novel electrochemical sensor development. Herein, cerium oxide (CeO2) nanoparticles were successfully loaded on reduced ...graphene oxide (RGO) by one-step hydrothermal synthesis approach, and the as-prepared nanocomposite (CeO2/RGO) was used as novel electrode material for electrochemical detection of tryptophan. The structure and composition of CeO2/RGO nanocomposite were fully characterized by transmission electron microscope (TEM), X-ray powder diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The electrochemical properties were characterized by several techniques such as cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). It was found that the CeO2/RGO nanocomposite electrode exhibits an enhanced peak current response compared with individual CeO2 or RGO material. The electrochemical sensor based CeO2/RGO material showed a selective and sensitive response toward tryptophan determination, and a linear range of 0.2–25 μM with a detection limit of 80 nM (S/N = 3) was achieved. The present electrochemical sensor displayed an excellent stability and reproducibility, and was successfully applied in the determination of tryptophan in real food and biological samples.
CeO2 was loaded on reduced graphene oxide (CeO2-RGO) and used as active electrode material for electrochemical detection of tryptophan in food and biological samples. Display omitted
•CeO2 loaded on reduced graphene oxide (CeO2-RGO) composite was facilely fabricated by a hydrothermal reduction approach.•The CeO2-RGO was used as a novel electrode material for tryptophan detection.•The present electrochemical sensor exhibited improved analytical performance.•The CeO2-RGO electrode material has been successfully used for tryptophan detection in milk and bovine serum samples.
The Kepler mission has discovered thousands of exoplanets around various stars with different spectral types (M, K, G, and F) and thus different masses and effective temperatures. Previous studies ...have shown that the planet occurrence rate, in terms of the average number of planets per star, drops with increasing stellar effective temperature (Teff). In this paper, with the final Kepler Data Release (DR25) catalog, we revisit the relation between stellar effective temperature (as well as mass) and planet occurrence, but in terms of the fraction of stars with planets and the number of planets per planetary system (i.e., planet multiplicity). We find that both the fraction of stars with planets and planet multiplicity decrease with increasing stellar temperature and mass. Specifically, about 75% late-type stars (Teff < 5000 K) have Kepler-like planets with an average planet multiplicity of ∼2.8, while for early-type stars (Teff > 6500 K) this fraction and the average multiplicity fall down to ∼35% and ∼1.8, respectively. The decreasing trend in the fraction of stars with planets is very significant with ΔAIC > 30, though the trend in planet multiplicity is somewhat tentative with ΔAIC ∼ 5. Our results also allow us to derive the dispersion of planetary orbital inclinations in relationship with stellar effective temperature. Interestingly, it is found to be similar to the well-known trend between obliquity and stellar temperature, indicating that the two trends might have a common origin.
Carbon dots (CDs) with tunable photoluminescence (PL) and a quantum yield of up to 35% in water were hydrothermally synthesized in one pot and separated via silica column chromatography. These ...separated CDs emitted bright and stable luminescence in gradient colors from blue to red under a single-wavelength UV light. They exhibited high optical uniformity; that is, every sample showed only one peak in the PL excitation spectrum, only one peak in the excitation-independent PL emission spectrum, and similar monoexponential fluorescence lifetimes. Although these samples had similar distributions of particle size and graphite structure in their carbon cores, the surface state gradually varied among the samples, especially the degree of oxidation. Therefore, the observed red shift in their emission peaks from 440 to 625 nm was ascribed to a gradual reduction in their band gaps with the increasing incorporation of oxygen species into their surface structures. These energy bands were found to depend on the surface groups and structures but not on the particle size, not as in traditional semiconductor quantum dots. In addition, because of their excellent PL properties and low cytotoxicity, these CDs could be used to image cells in different colors under a single-wavelength light source, and the red-emitting CDs could be used to image live mice because of the strong penetration capability of their fluorescence.
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