The Junggar‐Balkhash Ocean was a major branch of the southern Paleo‐Asian Ocean. The timing of its closure is important for understanding the history of the Central Asian Orogenic Belt. New ...sedimentological and geochronological data from the Late Paleozoic volcano‐sedimentary sequences in the Barleik Mountains of West Junggar, NW China, help to constrain the closure time of the Junggar‐Balkhash Ocean. Tielieketi Formation (Fm) is dominated by littoral sediments, but its upper glauconite‐bearing sandstone is interpreted to deposit rapidly in a shallow‐water shelf setting. By contrast, Heishantou Fm consists chiefly of volcanic rocks, conformably overlying or in fault contact with Tielieketi Fm. Molaoba Fm is composed of parallel‐stratified fine sandstone and sandy conglomerate with graded bedding, typical of nonmarine, fluvial deposition. This formation unconformably overlies the Tielieketi and Heishantou formations and is conformably covered by Kalagang Fm characterized by a continental bimodal volcanic association. The youngest U‐Pb ages of detrital zircons from sandstones and zircon U‐Pb ages from volcanic rocks suggest that the Tielieketi, Heishantou, Molaoba, and Kalagang formations were deposited during the Famennian‐Tournaisian, Tournaisian‐early Bashkirian, Gzhelian, and Asselian‐Sakmarian, respectively. The absence of upper Bashkirian to Kasimovian was likely caused by tectonic uplifting of the West Junggar terrane. This is compatible with the occurrence of coeval stitching plutons in the West Junggar and adjacent areas. The Junggar‐Balkhash Ocean should be finally closed before the Gzhelian, slightly later or concurrent with that of other ocean domains of the southern Paleo‐Asian Ocean.
Key Points
Sandstone and conglomerate of the Molaoba Formation were deposited in a fluvial environment during the Gzhelian (Pennsylvanian)
Absence of upper Bashkirian‐Kasimovian (Pennsylvanian) resulted from uplifting of the West Junggar terrane
Closure of Junggar‐Balkhash Ocean occurred before the Gzhelian, nearly coeval with that of other oceans in the southern Paleo‐Asian Ocean
In this study, a high‐performance photodetector comprised of formamidinium cesium lead iodide (FA1−xCsxPbI3) thin film is developed. The Cs‐doped FAPbI3 perovskite material is synthesized through a ...simple spin‐coating method, via which FA1−xCsxPbI3 with different Cs doping levels (x = 0.1, 0.15, 0.2, and 0.3) can be obtained. Further optoelectronic characterization reveals that the FA0.85Cs0.15PbI3 photodetector exhibits reproducible sensitivity to irradiation with wavelengths in the range from 240 to 750 nm, whereas it is weakly sensitive to wavelengths longer than 750 nm. The responsivity and specific detectivity are estimated to be around 5.7 A W−1 and 2.7 × 1013 cm Hz1/2 W–1, respectively. It is also worth noting that the present perovskite photodetector demonstrates an ultrafast response speed (tr/tf: 45 ns/91 ns) at zero bias voltage, which is probably related to the ultrafast lifetime and high quality of thin film according to the Hall effect study. Finally, this device shows a weak degradation in sensitivity to white light after storage at ambient condition for 45 days. The totality of the broadband sensitivity, high specific detectivity, ultrafast response speed, and self‐driven property renders the FA1−xCsxPbI3 an idea material for high‐performance photodetectors application.
A broadband photodetector is fabricated based on formamidinium cesium lead iodide (FA1−xCsxPbI3) thin film, which is synthesized through a simple spin‐coating strategy. The as‐fabricated device displays apparent sensitivity to irradiation ranging from 240 to 750 nm, with an ultrahigh specific detectivity of 2.7 × 1013 cm Hz1/2 W–1 and fast response speed (tr/tf: 45 ns/91 ns) at zero bias voltage.
Accurate and quantifiable detection of the specific wavelength is vital in different application scenarios. Herein, a novel self‐driven narrowband photodetector (NB‐PD) based on CH(NH2)2PbBr2.5I0.5 ...crystal film is employed for building a yellow light intensity meter. By taking advantage of the carrier collection narrowing mechanism, a sensitive NB‐PD with peak response at 580 nm and the full‐width at half‐maximum of 23 nm are successfully achieved. The asymmetric contact electrodes of Ag/Pt allow the device to work without bias. The optoelectronic analysis demonstrates that the NB‐PD achieves a maximum responsivity of 59.89 mA W−1, a fast response speed of 202/331 µs, and a high on/off ratio of 636 at zero bias. Then, through introducing the back‐end circuit, a yellow light intensity meter is constructed with the NB‐PD. The absolute error and relative error of the light meter are estimated to be lower than 0.08 mW cm−2 and 4.22%, respectively, indicating the good capability for the yellow light monitoring. Given the simple device geometry and good performance, the achieved yellow light intensity meter can also be extended to other narrowband light detection system.
This work presents a filter‐free CH(NH2)2PbBr2.5I0.5 single crystal narrow‐band photodetector through a simple solution method, which exhibits good performance in the yellow light band. A yellow light intensity meter is further built by combining with the back‐end circuit, capable of detecting a wide range of yellow light intensity in real‐time.
A large-scale global outbreak of coronavirus disease-19 (COVID-19) out of Wuhan, from China, occurred in January 2020. To examine the clinical characteristics of COVID-19 in infected patients out of ...Wuhan, from China.
Thirteen patients were confirmed to be infected with novel coronavirus-2019 (2019-nCoV) between January 27 and February 8, 2020, in Baoji city, Shannxi, northwestern China. Epidemiological and clinical information, and computed to morphology imaging data from all COVID-19 patients were collected; cases were divided into two groups according to the severity of infection (mild or severe).
Nine (9/13) COVID-19 patients exhibited mild disease severity, and defined as second-generation human-to-human transmission cases. Most patients (11/13) had a history of travel to or from Wuhan. There were no differences in sex and age between the mild and severe cases (all P > 0.05). A moderate degree of fever (11/13), cough (13/13), and fatigue (8/13) were common symptoms; however, there was no statistical difference between mild and severe cases in this regard (all P > 0.05). Oxyhemoglobin saturation and oxygenation index decreased, and C-reactive protein (CRP) and serum amyloid A (SAA) levels were elevated in all patients with COVID-19 infection, with statistically significant differences between those with severe disease and mild infection (all P < 0.05). Twelve of 13 COVID-19 patients exhibited changes in chest CT imaging features, and time course changes were different between mild and severe cases (all P < 0.05).
Most cases of COVID-19 infection were second-generation human-to-human transmissions from Wuhan and were mild in severity. The clinical characteristics of COVID-19 varied. Oxyhemoglobin saturation, oxygenation index, CRP and SAA levels, and CT features were reliable parameters to evaluate the severity of COVID-19 infection. However, a few patients with mild COVID-19 disease lacked typical characteristics such as fever and changes in CT imaging features.
Carnosic acid (CA), a natural catechol rosin diterpene, is used as an additive in animal feeds and human foods. However, the effects of CA on mammalian reproductive processes, especially early ...embryonic development, are unclear. In this study, we added CA to parthenogenetically activated porcine embryos in an in vitro culture medium to explore the influence of CA on apoptosis, proliferation, blastocyst formation, reactive oxygen species (ROS) levels, glutathione (GSH) levels, mitochondrial membrane potential, and embryonic development-related gene expression. The results showed that supplementation with 10 μM CA during in vitro culture significantly improved the cleavage rates, blastocyst formation rates, hatching rates, and total numbers of cells of parthenogenetically activated porcine embryos compared with no supplementation. More importantly, supplementation with CA also improved GSH levels and mitochondrial membrane potential, reduced natural ROS levels in blastomeres, upregulated Nanog, Sox2, Gata4, Cox2, Itga5, and Rictor expression, and downregulated Birc5 and Caspase3 expression. These results suggest that CA can improve early porcine embryonic development by regulating oxidative stress. This study elucidates the effects of CA on early embryonic development and their potential mechanisms, and provides new applications for improving the quality of in vitro-developed embryos.
Neritidae is one of the most diverse families of Neritimorpha and possesses euryhaline properties. Members of this family usually live on tropical and subtropical coasts and are mainly gregarious. ...The phylogenetic relationships between several subclasses of Gastropoda have been controversial for many years. With an increase in the number of described species of Neritidae, the knowledge of the evolutionary relationships in this family has improved. In the present study, we sequenced four complete mitochondrial genomes from two genera (Clithon and Nerita) and compared them with available complete mitochondrial genomes of Neritidae. Gene order exhibited a highly conserved pattern among three genera in the Neritidae family. Our results improved the phylogenetic resolution within Neritidae, and more comprehensive taxonomic sampling of subclass Neritimorpha was proposed. Furthermore, we reconstructed the divergence among the main lineages of 19 Neritimorpha taxa under an uncorrelated relaxed molecular clock.
In December 2019, a new type viral pneumonia cases occurred in Wuhan, Hubei Province; and then named "2019 novel coronavirus (2019-nCoV)" by the World Health Organization (WHO) on 12 January 2020. ...For it is a never been experienced respiratory disease before and with infection ability widely and quickly, it attracted the world's attention but without treatment and control manual. For the request from frontline clinicians and public health professionals of 2019-nCoV infected pneumonia management, an evidence-based guideline urgently needs to be developed. Therefore, we drafted this guideline according to the rapid advice guidelines methodology and general rules of WHO guideline development; we also added the first-hand management data of Zhongnan Hospital of Wuhan University. This guideline includes the guideline methodology, epidemiological characteristics, disease screening and population prevention, diagnosis, treatment and control (including traditional Chinese Medicine), nosocomial infection prevention and control, and disease nursing of the 2019-nCoV. Moreover, we also provide a whole process of a successful treatment case of the severe 2019-nCoV infected pneumonia and experience and lessons of hospital rescue for 2019-nCoV infections. This rapid advice guideline is suitable for the first frontline doctors and nurses, managers of hospitals and healthcare sections, community residents, public health persons, relevant researchers, and all person who are interested in the 2019-nCoV.
As a key component of batteries, the electrolyte determines the ion transport and interface chemistry of the cathode and anode. In this work, we develop a dual‐network structured hydrogel electrolyte ...composed of polyacrylamide (PAM), sodium alginate (SA) and potassium iodide (KI) for solid‐state zinc‐air/iodide hybrid batteries. The assembled hybrid battery shows excellent renewability and a long cycling life of 110 h with a high energy efficiency of 80 %. The ion‐crosslinked dual‐network structure endows the material with improved mechanical strength and increased ionic conductivity. More importantly, the introduction of iodine species not only offers more favorable cathodic kinetics of iodide/iodate redox than oxygen electrocatalysis but also regulates the solvation structure of zinc ions to ensure better interface stability. This work provides significant concepts for developing novel solid‐state electrolytes to realize high‐performance energy devices and technologies.
A novel dual‐network structured hydrogel realizes stable and rechargeable solid‐state zinc‐air/iodide hybrid batteries.
The electronic and chemical properties of graphene can be modulated by chemical doping foreign atoms and functional moieties. The general approach to the synthesis of nitrogen-doped graphene (NG), ...such as chemical vapor deposition (CVD) performed in gas phases, requires transitional metal catalysts which could contaminate the resultant products and thus affect their properties. In this paper, we propose a facile, catalyst-free thermal annealing approach for large-scale synthesis of NG using low-cost industrial material melamine as the nitrogen source. This approach can completely avoid the contamination of transition metal catalysts, and thus the intrinsic catalytic performance of pure NGs can be investigated. Detailed X-ray photoelectron spectrum analysis of the resultant products shows that the atomic percentage of nitrogen in doped graphene samples can be adjusted up to 10.1%. Such a high doping level has not been reported previously. High-resolution N1s spectra reveal that the as-made NG mainly contains pyridine-like nitrogen atoms. Electrochemical characterizations clearly demonstrate excellent electrocatalytic activity of NG toward the oxygen reduction reaction (ORR) in alkaline electrolytes, which is independent of nitrogen doping level. The present catalyst-free approach opens up the possibility for the synthesis of NG in gram-scale for electronic devices and cathodic materials for fuel cells and biosensors.
Ammonia is a vital intermediate in the hydrogen desorption process of Metal-N-H system. KH has strong reactivity with NH3 to form KNH2. We speculate that KNH2 is also an intermediate formed during ...hydrogen desorption of the potassium-doped M-N-H systems. In this research, the dehydrogenation performance of the KNH2-doped LiNH2 and LiH composition was first studied. Compared with the broad dehydrogenation curve of the composite material of LiNH2 and LiH without the catalyst, the dehydrogenation curve of 0.05 mol KNH2-doped composite material was significantly narrowed. The initial and peak dehydrogenation temperature of the composite to which 0.05 mol of KNH2 was added was lowered remarkably. Besides, the cyclic dehydrogenation properties of the LiNH2 and LiH system was also significantly enhanced by the introduction of KNH2. The cyclic conversion of KNH2 to KH is the main reason for the enhancement of the hydrogen evolution performance of the LiNH2–LiH system doped with KNH2. We found the KNH2-doped Li–N–H system exhibits similar dehydrogenation property with that of the KH-doped Li–N–H system. This work proves that KNH2 plays a key role in improving the hydrogen desorption performances of the potassium-doped M-N-H systems.
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•Hydrogen desorption properties of the KNH2-doped Li–N–H system was examined.•Hydrogen desorption kinetics are significantly enhanced by introducing KNH2.•The dehydrogenation temperature is lowered drastically.•The improved properties induce from the cyclic conversion from KNH2 to KH.•KNH2 may be formed during dehydrogenation of the potassium-doped M-N-H system.
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