In this paper, we propose a novel contour-seed pairs learning-based framework for robust and automated cell/nucleus segmentation. Automated granular object segmentation in microscopy images has ...significant clinical importance for pathology grading of the cell carcinoma and gene expression. The focus of the past literature is dominated by either segmenting a certain type of cells/nuclei or simply splitting the clustered objects without contours inference of them. Our method addresses these issues by formulating the detection and segmentation tasks in terms of a unified regression problem, where a cascade sparse regression chain model is trained and then applied to return object locations and entire boundaries of clustered objects. In particular, we first learn a set of online convolutional features in each layer. Then, in the proposed cascade sparse regression chain, with the input from the learned features, we iteratively update the locations and clustered object boundaries until convergence. In this way, the boundary evidences of each individual object can be easily delineated and be further fed to a complete contour inference procedure optimized by the minimum description length principle. For any probe image, our method enables to analyze free-lying and overlapping cells with complex shapes. Experimental results show that the proposed method is very generic and performs well on contour inferences of various cell/nucleus types. Compared with the current segmentation techniques, our approach achieves state-of-the-art performances on four challenging datasets, i.e., the kidney renal cell carcinoma histopathology dataset, Drosophila Kc167 cellular dataset, differential interference contrast red blood cell dataset, and cervical cytology dataset.
A new palladium‐catalyzed reductive 5+1 cycloaddition of 3‐acetoxy‐1,4‐enynes with CO, enabled by hydrosilanes, has been developed for delivering valuable functionalized phenols. This methodology ...employs hydrosilanes as the external reagent to facilitate the 5+1 carbonylative benzannulation. The reaction is a conceptually and mechanistically novel carbonylative cycloaddition route for the construction of substituted phenols, through the formation of four new chemical bonds, with excellent functional‐group tolerance.
Pd & CO: Employing reductive palladium catalysis enables a new 5+1 carbonylative benzannulation of 3‐acetoxy‐1,4‐enynes with CO and hydrosilanes. This reaction is facilitated by hydrosilanes, and allows straightforward and practical access to functionalized phenols with excellent functional‐group tolerance and high selectivity.
The aim of this study was to characterize the molecular relationship, origin and historical biogeography of the species in important brown rot fungal genus Laetiporus from East Asia, Europe, ...Pan-America, Hawaii and South Africa. We used six genetic markers to estimate a genus-level phylogeny including (1) the internal transcribed spacer (ITS), (2) nuclear large subunit rDNA (nrLSU), (3) nuclear small subunit rDNA (nrSSU), (4) translation elongation factor 1-α (EF-1α), (5) DNA-directed RNA polymerase II subunit 2 (RPB2), and (6) mitochondrial small subunit rDNA (mtSSU).
Results of multi-locus phylogenetic analyses show clade support for at least seventeen species-level lineages including two new Laetiporus in China. Molecular dating using BEAST estimated the present crown group diverged approximately 20.16 million years ago (Mya) in the early Miocene. Biogeographic analyses using RASP indicated that Laetiporus most likely originated in temperate zones with East Asia and North America having the highest probability (48%) of being the ancestral area.
Four intercontinental dispersal routes and a possible concealed dispersal route were established for the first time.
•Bacterial community structure and diversity in Baiyangdian Lake were assessed.•Dominant bacteria in different habitats at different seasons were assessed.•Main functional groups were ...sulfur-oxidizing, sulfur-reducing, nitrifying and pollutant-degrading bacteria.•Main factors affecting bacterial community composition were pH, phosphorus and heavy metals.•Bacterial community composition, evenness and diversity varied more significantly with habitat.
Benthic bacteria are drivers of aquatic ecosystem material circulation and energy flow, and are sensitive to environmental changes. In this study, a total of 79 sediment samples were collected from four representative habitat types (duck farm, fish farm, lotus pond and residential area) and one reference site (conservation district) of Baiyangdian Lake, North China, in three seasons (winter, spring and summer). The physical and chemical properties and the levels of contaminants in sediment were determined. Bacterial communities were studied by 16S rRNA high-throughput sequencing techniques. The result showed that, Proteobacteria, Chloroflexi, Bacteroidetes, Firmicutes and Actinobacteria were the dominant species at the phylum level in Baiyangdian. Sulfuricurvum, Thiobacillus Dechloromonas, Sulfurovum, Nitrospira and Desulfatiglans were the dominant species at the genus level. The dominant genus was different among different habitats. Proteobacteria exhibited the highest relative abundance in all seasons, and the relative abundance of dominant bacteria was highest in winter. The main functional group from the sampling sites were contamination tolerance bacteria, such as sulfur-oxidizing, sulfate-reducing and nitrifying bacteria. Sulfur-oxidizing bacteria were found mainly in duck farms and residential areas, whereas sulfate-reducing bacteria and nitrifying bacteria occurred in lotus ponds. Habitat type was the most important factor influencing the bacterial community composition, evenness and diversity. Sediment pH and the amount of active phosphorus played the most important role in the composition of the bacterial community, and the heavy metals (Zn, Mn and Cr) and organic pollutants (polycyclic aromatic hydrocarbons, PAH) also had moderate influence. As Baiyangdian Lake is the central of Xiong’an New Area, the water quality management has become the hottest topic. Plenty of researches about environmental variables and aquatic species were taken, but lacking report of bacteria. This study provide basic information of bacterial community composition in this area, and help to understand the response of the bacterial community to habitat and seasonal change, which provide a scientific basis for the recovery and reconstruction of the degraded ecosystem.
Intrinsically low conductivity and poor reactivity restrict many semiconductors from electrochemical detection. Usually, metal- and carbon-based modifications of semiconductors are necessary, making ...them complex, expensive, and unstable. Here, for the first time, we present a surface-electronic-state-modulation-based concept applied to semiconductors. This concept enables pure semiconductors to be directly available for ultrasensitive electrochemical detection of heavy-metal ions without any modifications. As an example, a defective single-crystalline (001) TiO2 nanosheet exhibits high electrochemical performance toward Hg(II), including a sensitivity of 270.83 μA μM–1 cm–2 and a detection limit of 0.017 μM, which is lower than the safety standard (0.03 μM) of drinking water established by the World Health Organization (WHO). It has been confirmed that the surface oxygen vacancy adsorbs an O2 molecule while the Ti3+ donates an electron, forming the O2 •– species that facilitate adsorption of Hg(II) and serve as active sites for electron transfer. These findings not only extend the electrochemical sensing applications of pure semiconductors but also stimulate new opportunities for investigating atom-level electrochemical behaviors of semiconductors by surface electronic-state modulation.
Here we describe the one‐pot construction of the pyrrolo4,3,2‐dequinolinone scaffold by a cascade nitration/cyclization sequence of 1,7‐enynes with tBuONO and H2O. The cascade proceeds through alkene ...nitration, 1,7‐enyne 6‐exo‐trig cyclization, CH nitrations, and redox cyclization, and exhibits excellent functional group tolerance. The mechanism was investigated using in situ high‐resolution mass spectrometry (HR‐MS).
Nitration cascade: The pyrrolo4,3,2‐dequinolinone scaffold was synthesized by a metal‐free reaction of N‐(2‐(ethynyl)aryl)acrylamides, tert‐butyl nitrite and H2O. This cascade reaction is triggered by alkene nitration followed by 1,7‐enyne 6‐exo‐trig cyclization, CH nitrations, and redox cyclization and forms the product in good yields.
Sodium is globally available, which makes a sodium-ion rechargeable battery preferable to a lithium-ion battery for large-scale storage of electrical energy, provided a host cathode for Na can be ...found that provides the necessary capacity, voltage, and cycle life at the prescribed charge/discharge rate. Low-cost hexacyanometallates are promising cathodes because of their ease of synthesis and rigid open framework that enables fast Na+ insertion and extraction. Here we report an intriguing effect of interstitial H2O on the structure and electrochemical properties of sodium manganese(II) hexacyanoferrates(II) with the nominal composition Na2MnFe(CN)6·zH2O (Na2−δMnHFC). The newly discovered dehydrated Na2−δMnHFC phase exhibits superior electrochemical performance compared to other reported Na-ion cathode materials; it delivers at 3.5 V a reversible capacity of 150 mAh g–1 in a sodium half cell and 140 mAh g–1 in a full cell with a hard-carbon anode. At a charge/discharge rate of 20 C, the half-cell capacity is 120 mAh g–1, and at 0.7 C, the cell exhibits 75% capacity retention after 500 cycles.
The adsorption behavior and mechanism of amino-crosslinked hypromellose (AHM) adsorbent crosslinked with epichlorohydrin and modified with diethylenetriamine were studied. This material is ...unprecedented, and the modification method used to obtain it is relatively simple. The parameters affecting the adsorption of methyl orange (MO) dye by AHM such as pH, adsorbent dosage, contact time, initial concentration, and temperature were investigated. The experimental results show that the optimal adsorption time and dosage were 30 min and 3.6 g L
−1
, respectively. It was found that the pseudo-second-order kinetic model and the Langmuir isotherm adsorption model provide a good description of the adsorption process, indicating that the adsorption of MO by AHM is mainly controlled by the chemical bonding interactions. Analysis of the thermodynamic parameters showed that the process of MO adsorption on AHM is spontaneous and endothermic. The morphology, surface chemical bonding, crystal structure, specific surface area, and temperature stability of AHM were characterized by SEM, FTIR, XRD, BET, and TGA measurements. The results showed that the AHM materials had large pores, which is favorable for adsorption. AHM may also have an increased content of amino-functional groups that are beneficial for adsorption. The maximum MO adsorption capacities of AHM were 15.56 mg g
−1
, whereas the maximum adsorption capacity of the unmodified hypromellose was 2.12 mg g
−1
. It is important to note that the adsorption efficiency of AHM remained above 62% after five adsorption–desorption experiments. Therefore, AHM can be used as an efficient and environmentally friendly adsorbent material for the removal of MO from water.
This study presents a rigorous computational framework for visualizing uncertainty of tsunami hazard and risk assessment. The methodology consists of three modules: (i) earthquake source ...characterization and stochastic simulation of slip distribution, (ii) tsunami propagation and inundation, and (iii) tsunami damage assessment and loss estimation. It takes into account numerous stochastic tsunami scenarios to evaluate the uncertainty propagation of earthquake source characteristics in probabilistic tsunami risk analysis. An extensive Monte Carlo tsunami inundation simulation is implemented for the 2011 Tohoku tsunami (focusing upon on Rikuzentakata along the Tohoku coast of Japan) using 726 stochastic slip models derived from eleven inverted source models. By integrating the tsunami hazard results with empirical tsunami fragility functions, probabilistic tsunami risk analysis and loss estimation are carried out; outputs from the analyses are displayed using various visualization methods. The developed framework is comprehensive, and can provide valuable insights in promoting proactive tsunami risk management and in improving emergency response capability.
Difunctionalization: Inexpensive and environmentally benign FeCl3 catalyzes the oxidative 1,2‐alkylarylation of activated alkenes with an aryl C(sp2)H bond and a C(sp3)H bond adjacent to a ...heteroatom. This reaction is a new strategy for the synthesis of oxindoles and makes use of DBU as ligand and TBHP as oxidant (see scheme, TBHP=tert‐butyl hydrogenperoxide).
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