Since December 2019, an epidemic caused by novel coronavirus (2019-nCoV) infection has occurred unexpectedly in China. As of 8 pm, 31 January 2020, more than 20 pediatric cases have been reported in ...China. Of these cases, ten patients were identified in Zhejiang Province, with an age of onset ranging from 112 days to 17 years. Following the latest
National recommendations for diagnosis and treatment of pneumonia caused by 2019-nCoV
(the 4th edition) and current status of clinical practice in Zhejiang Province, recommendations for the diagnosis and treatment of respiratory infection caused by 2019-nCoV for children were drafted by the National Clinical Research Center for Child Health, the National Children’s Regional Medical Center, Children’s Hospital, Zhejiang University School of Medicine to further standardize the protocol for diagnosis and treatment of respiratory infection in children caused by 2019-nCoV.
Soft robots have the appealing advantages of being highly flexible and adaptive to complex environments. However, the low‐stiffness nature of the constituent materials makes soft robotic systems ...incompetent in tasks requiring relatively high load capacity. Despite recent attempts to develop stiffness‐tunable soft actuators by employing variable stiffness materials and structures, the reported stiffness‐tunable actuators generally suffer from limitations including slow responses, small deformations, and difficulties in fabrication with microfeatures. This work presents a paradigm to design and manufacture fast‐response, stiffness‐tunable (FRST) soft actuators via hybrid multimaterial 3D printing. The integration of a shape memory polymer layer into the fully printed actuator body enhances its stiffness by up to 120 times without sacrificing flexibility and adaptivity. The printed Joule‐heating circuit and fluidic cooling microchannel enable fast heating and cooling rates and allow the FRST actuator to complete a softening–stiffening cycle within 32 s. Numerical simulations are used to optimize the load capacity and thermal rates. The high load capacity and shape adaptivity of the FRST actuator are finally demonstrated by a robotic gripper with three FRST actuators that can grasp and lift objects with arbitrary shapes and various weights spanning from less than 10 g to up to 1.5 kg.
A fast‐response, stiffness‐tunable (FRST) soft actuator is fabricated by hybrid multimaterial 3D printing. Owing to the thermomechanical properties of an embedded shape memory polymer layer, the actuator exhibits flexibility when heated and high stiffness (120 times stiffer than its purely elastomeric counterpart) when cooled. Assisted by Joule‐heating and fluidic cooling, the heating–cooling cycle is completed within 32 s.
Wild apple (Malus sieversii) is under second-class national protection in China and one of the lineal ancestors of cultivated apples worldwide. In recent decades, the natural habitation area of wild ...apple trees has been seriously declining, resulting in a lack of saplings and difficulty in population regeneration. Artificial near-natural breeding is crucial for protecting and restoring wild apple populations, and adding nitrogen (N) and phosphorous (P) is one of the important measures to improve the growth performance of saplings. In this study, field experiments using N (CK, N1, N2, and N3: 0, 10, 20, and 40 g m
yr
, respectively), P (CK, P1, P2, and P3: 0, 2, 4, and 8 g m
yr
, respectively), N20Px (CK, N2P1, N2P2, and N2P3: N20P2, N20P4 and N20P8 g m
yr
, respectively), and NxP4 (CK, N1P2, N2P2, and N3P2: N10P4, N20P4, and N40P4 g m
yr
, respectively) treatments (totaling 12 levels, including one CK) were conducted in four consecutive years. The twig traits (including four current-year stem, 10 leaf, and three ratio traits) and comprehensive growth performance of wild apple saplings were analyzed under different nutrient treatments.
N addition had a significantly positive effect on stem length, basal diameter, leaf area, and leaf dry mass, whereas P addition had a significantly positive effect on stem length and basal diameter only. The combination of N and P (NxP4 and N20Px) treatments evidently promoted stem growth at moderate concentrations; however, the N20Px treatment showed a markedly negative effect at low concentrations and a positive effect at moderate and high concentrations. The ratio traits (leaf intensity, leaf area ratio, and leaf to stem mass ratio) decreased with the increase in nutrient concentration under each treatment. In the plant trait network, basal diameter, stem mass, and twig mass were tightly connected to other traits after nutrient treatments, indicating that stem traits play an important role in twig growth. The membership function revealed that the greatest comprehensive growth performance of saplings was achieved after N addition alone, followed by that under the NxP4 treatment (except for N40P4).
Consequently, artificial nutrient treatments for four years significantly but differentially altered the growth status of wild apple saplings, and the use of appropriate N fertilizer promoted sapling growth. These results can provide scientific basis for the conservation and management of wild apple populations.
Coronavirus disease 2019 (COVID‐19) is a novel type of highly contagious pneumonia caused by the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). Despite the strong efforts taken to ...control the epidemic, hundreds of thousands of people were infected worldwide by 11 March, and the situation was characterized as a pandemic by the World Health Organization. Pregnant women are more susceptible to viral infection due to immune and anatomic alteration, though hospital visits may increase the chance of infection, the lack of medical care during pregnancy may do more harm. Hence, a well‐managed system that allows pregnant women to access maternal health care with minimum exposure risk is desired during the outbreak. Here, we present the managing processes of three pregnant women who had fever during hospitalization in the gynecology or obstetrics department, and then, we further summarize and demonstrate our maternal health care management strategies including antenatal care planning, patient triage based on the risk level, admission control, and measures counteracting emergencies and newly discovered high‐risk cases at in‐patient department. In the meantime, we will explain the alterations we have done throughout different stages of the epidemic and also review relative articles in both Chinese and English to compare our strategies with those of other areas. Although tens of COVID‐19 cases were confirmed in our hospital, no nosocomial infection has occurred and none of the pregnant women registered in our hospital was reported to be infected.
Highlights
Demonstration of three cases of pregnant women who developed a fever during hospitalization.
Researchers have spared no effort to design new thermally activated delayed fluorescence (TADF) emitters for high‐efficiency organic light‐emitting diodes (OLEDs). However, efficient long‐wavelength ...TADF emitters are rarely reported. Herein, a red TADF emitter, TPA–PZCN, is reported, which possesses a high photoluminescence quantum yield (ΦPL) of 97% and a small singlet–triplet splitting (ΔEST) of 0.13 eV. Based on the superior properties of TPA–PZCN, red, deep‐red, and near‐infrared (NIR) OLEDs are fabricated by utilizing different device structure strategies. The red devices obtain a remarkable maximum external quantum efficiency (EQE) of 27.4% and an electroluminescence (EL) peak at 628 nm with Commission Internationale de L'Eclairage (CIE) coordinates of (0.65, 0.35), which represents the best result with a peak wavelength longer than 600 nm among those of the reported red TADF devices. Furthermore, an exciplex‐forming cohost strategy is adopted. The devices achieve a record EQE of 28.1% and a deep‐red EL peak at 648 nm with the CIE coordinates of (0.66, 0.34). Last, nondoped devices exhibit 5.3% EQE and an NIR EL peak at 680 nm with the CIE coordinates of (0.69, 0.30).
A novel red thermally activated delayed fluorescence (TADF) emitter, TPA–PZCN, is designed and synthesized. It simultaneously possesses a high ΦPL of 97% and a small ΔEST of 0.13 eV. Red, deep‐red, and near‐infrared organic light‐emitting diodes (LEDs) based on it achieve record external quantum efficiencies of 27.4%, 28.1%, and 5.3%, respectively, which are the best performances in comparison with LEDs having a similar device structure.
4D printing is an emerging fabrication technology that enables 3D printed structures to change configuration over “time” in response to an environmental stimulus. Compared with other soft active ...materials used for 4D printing, shape‐memory polymers (SMPs) have higher stiffness, and are compatible with various 3D printing technologies. Among them, ultraviolet (UV)‐curable SMPs are compatible with Digital Light Processing (DLP)‐based 3D printing to fabricate SMP‐based structures with complex geometry and high‐resolution. However, UV‐curable SMPs have limitations in terms of mechanical performance, which significantly constrains their application ranges. Here, a mechanically robust and UV‐curable SMP system is reported, which is highly deformable, fatigue resistant, and compatible with DLP‐based 3D printing, to fabricate high‐resolution (up to 2 µm), highly complex 3D structures that exhibit large shape change (up to 1240%) upon heating. More importantly, the developed SMP system exhibits excellent fatigue resistance and can be repeatedly loaded more than 10 000 times. The development of the mechanically robust and UV‐curable SMPs significantly improves the mechanical performance of the SMP‐based 4D printing structures, which allows them to be applied to engineering applications such as aerospace, smart furniture, and soft robots.
A mechanically robust and UV‐curable shape‐memory polymer (SMP) system can be stretched by up to 1240% of its original length and is compatible with Digital Light Processing (DLP)‐based high‐resolution 3D printing technology (up to 2 µm). The high deformability and fatigue resistance (more than 10 000 cycles loading–unloading) make the SMP an ideal 4D printing material for engineering applications.
Heritable variation in plant phenotypes, and thus potential for evolutionary change, can in principle not only be caused by variation in DNA sequence, but also by underlying epigenetic variation. ...However, the potential scope of such phenotypic effects and their evolutionary significance are largely unexplored.
Here, we conducted a glasshouse experiment in which we tested the response of a large number of epigenetic recombinant inbred lines (epiRILs) of Arabidopsis thaliana – lines that are nearly isogenic but highly variable at the level of DNA methylation – to drought and increased nutrient conditions.
We found significant heritable variation among epiRILs both in the means of several ecologically important plant traits and in their plasticities to drought and nutrients. Significant selection gradients, that is, fitness correlations, of several mean traits and plasticities suggest that selection could act on this epigenetically based phenotypic variation.
Our study provides evidence that variation in DNA methylation can cause substantial heritable variation of ecologically important plant traits, including root allocation, drought tolerance and nutrient plasticity, and that rapid evolution based on epigenetic variation alone should thus be possible.
Intelligent education is an intelligent education platform that integrates correct education concept and Internet of things, big data, cloud computing and other technologies. This paper hopes to use ...the construction of the composition scoring model to further construct a computer scoring system for college English translation, which can give students a translation score and give feedback evaluation based on the quality of the translation. In this paper, according to the knowledge of the existing automatic scoring system at home and abroad, the feature selection method (TF-IDF, IG, CHI) is discussed and analyzed. Moreover, this paper studies the impact of our composition automatic scoring from the perspective of linguistics. In addition, this paper uses the multiple regression method to evaluate the final score. The features considered in this paper mainly include simple linguistic features and complex linguistic features. Finally, performance analysis of the algorithm model is performed by setting up a control experiment. The research results show that the proposed algorithm model has certain effects. The future trend is to form adult auxiliary machines through various human-computer interaction technologies, which will reshape future learning and education and form a new teaching form.
Efficient emission of purely organic room‐temperature phosphorescence (RTP) is of great significant for potential application in optoelectronics and photobiology. Herein, we report an uncommon ...phosphorescent effect of organic single molecule enhanced by resulting supramolecular assembly of host–guest complexation. The chromophore bromophenyl‐methyl‐pyridinium (PY) with different counterions as guests display various phosphorescence quantum yields from 0.4 % to 24.1 %. Single crystal X‐ray diffraction results indicate that the chromophore with iodide counterion (PYI) exhibits the highest efficiency maybe due to the halogen‐bond interactions. Significantly, the nanosupramolecular assembly of PY chloride complexation with the cucurbit6uril gives a greatly enhanced phosphorescent quantum yield up to 81.2 % in ambient. Such great enhancement is because of the strict encapsulation of cucurbit6uril, which prevents the nonradiative relaxation and promotes intersystem crossing (ISC). This supramolecular assembly concept with counterions effect provides a novel approach for the improvement of RTP.
An uncommon phosphorescent effect of an organic single molecule enhanced by supramolecular assembly of host–guest complexation is reported. The chromophore bromophenyl‐methyl‐pyridinium (PY) gives an enhanced phosphorescent efficiency of 81.2 % under ambient conditions after complexation with cucurbit6uril. The strict encapsulation of cucurbit6uril suppresses the nonradiative relaxation and promotes intersystem crossing.
Flexible transparent electrodes (FTEs) with an embedded metal mesh are considered a promising alternative to traditional indium tin oxide (ITO) due to their excellent photoelectric performance, ...surface roughness, and mechanical and environmental stability. However, great challenges remain for achieving simple, cost‐effective, and environmentally friendly manufacturing of high‐performance FTEs with embedded metal mesh. Herein, a maskless, templateless, and plating‐free fabrication technique is proposed for FTEs with embedded silver mesh by combining an electric‐field‐driven (EFD) microscale 3D printing technique and a newly developed hybrid hot‐embossing process. The final fabricated FTE exhibits superior optoelectronic properties with a transmittance of 85.79%, a sheet resistance of 0.75 Ω sq−1, a smooth surface of silver mesh (Ra ≈ 18.8 nm) without any polishing treatment, and remarkable mechanical stability and environmental adaptability with a negligible increase in sheet resistance under diverse cyclic tests and harsh working conditions (1000 bending cycles, 80 adhesion tests, 120 scratch tests, 100 min ultrasonic test, and 72 h chemical attack). The practical viability of this FTE is successfully demonstrated with a flexible transparent heater applied to deicing. The technique proposed offers a promising fabrication strategy with a cost‐effective and environmentally friendly process for high‐performance FTE.
A maskless, templateless, and plating‐free fabrication method for high‐performance flexible transparent electrodes with embedded silver mesh is proposed by combining an electric‐field‐driven microscale 3D printing technique and a hybrid hot‐embossing process. The flexible transparent electrode with embedded silver mesh exhibits excellent photoelectric properties, remarkable mechanical stability, and environmental adaptability.
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