In this work, we report a conceptual strategy for prolonging foliar pesticide retention by using an adhesive polydopamine (PDA) microcapsule to encapsulate avermectin, thereby minimizing its volatilization and improving its residence time on crop surfaces. Polydopamine coated avermectin (Av@PDA) microcapsules were prepared by emulsion interfacial-polymerization and characterized by Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy, field-emission scanning electron microscope, and transmission electron microscopy. The in situ synthesis route confers Av@PDA microcapsules with remarkable avermectin loading ability of up to 66.5% (w/w). Kinetic study of avermectin release demonstrated that Av@PDA microcapsules exhibit sustained- and controlled-release properties. The adhesive property of Av@PDA microcapsules on different surfaces was verified by a comparative study between Av@PDA and passivated Av@SiO2 and Av@PDA@SiO2 capsules with silica shell. Moreover, PDA shell could effectively shield UV irradiation and so protect avermectin from photodegradation, making it more applicable for foliar spraying. Meanwhile, it is determinated that Av@PDA microcapsules have good mechanical stability property.

Perovskite ferroelectric BiFeO has been extensively researched in many application fields, but has rarely been investigated for the energy conversion of tiny mechanical motions in electricity in spite of its large theoretical remnant polarization. Here we demonstrate the fabrication of a flexible piezoelectric nanogenerator based on BiFeO nanoparticles (NPs), which were synthesized using a sol-gel process. The BiFeO NPs-PDMS composite device exhibits an output open circuit voltage of ∼3 V and short circuit current of ∼250 nA under repeated hand pressing. The output generation mechanism from the PNG is discussed on the basis of the alignment of electric dipoles in the composite film. It is demonstrated that the output power from the PNG can directly drive the light-emitting diode (LED) and charge capacitor. These results demonstrate that BiFeO nanomaterials have the potential for large-scale lead-free piezoelectric nanogenerator applications.

High-density genetic linkage maps are necessary for precisely mapping quantitative trait loci (QTLs) controlling grain shape and size in wheat. By applying the Infinium iSelect 9K SNP assay, we have constructed a high-density genetic linkage map with 269 F 8 recombinant inbred lines (RILs) developed between a Chinese cornerstone wheat breeding parental line Yanda1817 and a high-yielding line Beinong6. The map contains 2431 SNPs and 128 SSR & EST-SSR markers in a total coverage of 3213.2 cM with an average interval of 1.26 cM per marker. Eighty-eight QTLs for thousand-grain weight (TGW), grain length (GL), grain width (GW) and grain thickness (GT) were detected in nine ecological environments (Beijing, Shijiazhuang and Kaifeng) during five years between 2010–2014 by inclusive composite interval mapping (ICIM) (LOD≥2.5). Among which, 17 QTLs for TGW were mapped on chromosomes 1A, 1B, 2A, 2B, 3A, 3B, 3D, 4A, 4D, 5A, 5B and 6B with phenotypic variations ranging from 2.62% to 12.08%. Four stable QTLs for TGW could be detected in five and seven environments, respectively. Thirty-two QTLs for GL were mapped on chromosomes 1B, 1D, 2A, 2B, 2D, 3B, 3D, 4A, 4B, 4D, 5A, 5B, 6B, 7A and 7B, with phenotypic variations ranging from 2.62% to 44.39%. QGl.cau-2A.2 can be detected in all the environments with the largest phenotypic variations, indicating that it is a major and stable QTL. For GW, 12 QTLs were identified with phenotypic variations range from 3.69% to 12.30%. We found 27 QTLs for GT with phenotypic variations ranged from 2.55% to 36.42%. In particular, QTL QGt.cau-5A.1 with phenotypic variations of 6.82–23.59% was detected in all the nine environments. Moreover, pleiotropic effects were detected for several QTL loci responsible for grain shape and size that could serve as target regions for fine mapping and marker assisted selection in wheat breeding programs.

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Recently, the recurrence of positive SARS-CoV-2 viral RNA in recovered COVID-19 patients is receiving more attention. Herein we report a cohort study on the follow-up of 182 recovered patients under medical isolation observation. Twenty (10.99%) patients out of the 182 were detected to be SARS-CoV-2 RNA positive (re-positives), although none showed any clinical symptomatic recurrence, indicating that COVID-19 responds well to treatment. Patients aged under 18 years had higher re-positive rates than average, and none of the severely ill patients re-tested positive. There were no significant differences in sex between re-positives and non-re-positives. Notably, most of the re-positives turned negative in the following tests, and all of them carried antibodies against SARS-CoV-2. This indicates that they might not be infectious, although it is still important to perform regular SARS-CoV-2 RNA testing and follow-up for assessment of infectivity. The findings of this study provide information for improving the management of recovered patients, and for differentiating the follow-up of recovered patients with different risk levels. The current pneumonia epidemic (COVID-19), caused by the SARS-CoV-2 coronavirus has spread to more than 200 countries. There have been more than 8 million confirmed cases and up to 440,000 deaths (as of June 18, 2020) 1 , raising a high level of concern all over the world. Previous studies have mainly focused on the clinical and epidemiological characteristics of patients infected with SARS-CoV-2 2-4. With the increase in the number of recovered patients, follow-up and detection are particularly important. Previous studies have found that patients who have recovered from COVID-19 are still testing positive for SARS-CoV-2 5-7. A single center study reported that 7.41% of COVID-19 patients re-tested positive for SARS-CoV-2 RNA by real-time reverse transcriptase polymerase chain reaction (RT-PCR) test after discharge 8 , and this finding has challenged the current hospital discharge criteria for containing the pandemic. The present study analyzed the SARS-CoV-2 viral RNA test results in all 182 recovered COVID-19 patients in Shenzhen before April 21st during a 14-day medical isolation observation period, to provide more reference for containing the pandemic more effectively. Results Patients under 18 years old, and mild and moderately patients have a higher risk of re-testing positive. Among all the recovered and isolated patients, 182 of them satisfied the inclusion criteria of this study. They were all re-tested at least once. Eighty-four (46.2%) were males and 98 (53.8%) were females, and the average age was 46.4 ± 17.1 years (median 49 years, range 1-81 years). Thirty-nine (21.4%) had severe symptoms, and 143 (78.6%) had mild and moderate symptoms (Table 1). A few of them showed different symptoms (mild flu, allergic rhinitis, smoking-induced sore throat) during medical isolation, although COVID-19 symptoms did not recur. Twenty patients out of the 182 re-tested positive (13 females, seven m...

Recently, the recurrence of positive SARS-CoV-2 viral RNA in recovered COVID-19 patients get more attention. Here we report a cohort study on the follow up of 182 recovered patients under medical isolation observation. There are 20 (10.99 %) patients out of the 182 were detected SARS-CoV-2 RNA turned positive, but none of them shows any clinical symptomatic recurrence indicating that COVID-19 has a good prognosis. Females and young patients aged under 15 have higher re-positive rate than the average, and none of the severe patients turned re-positive. Notably, most of the re-positive cases turn negative in the followed tests, suggesting that the importance of dynamic surveillance of SARS-CoV-2 RNA for infectivity assessment.

Pu isotopes and (137)Cs were analyzed using sector field ICP-MS and γ spectrometry, respectively, in surface sediment and core sediment samples from the Yangtze River estuary. (239+240)Pu activity and (240)Pu/(239)Pu atom ratios (>0.18) shows a generally increasing trend from land to sea and from north to south in the estuary. This spatial distribution pattern indicates that the Pacific Proving Grounds (PPG) source Pu transported by ocean currents was intensively scavenged into the suspended sediment under favorable conditions, and mixed with riverine sediment as the water circulated in the estuary. This process is the main control for the distribution of Pu in the estuary. Moreover, Pu is also an important indicator for monitoring the changes of environmental radioactivity in the estuary as the river basin is currently the site of extensive human activities and the sea level is rising because of global climate changes. For core sediment samples the maximum peak of (239+240)Pu activity was observed at a depth of 172 cm. The sedimentation rate was estimated on the basis of the Pu maximum deposition peak in 1963-1964 to be 4.1 cm/a. The contributions of the PPG close-in fallout Pu (44%) and the riverine Pu (45%) in Yangtze River estuary sediments are equally important for the total Pu deposition in the estuary, which challenges the current hypothesis that the riverine Pu input was the major source of Pu budget in this area.

in Wiley InterScience (www.interscience.wiley.com).On the analogy of the water-using networks with single contaminant, we will introduce new methodology concepts: the concentration potentials of the demand streams and those of the source streams in the water-using systems with multiple contaminants, based on the overall allocation possibility of the source streams to the demand streams. In the design procedure, the performing order of the processes is determined by the inlet concentration potentials of the processes. The processes with the lowest inlet concentration potential will be performed first. When satisfying the inlet stream of the process being performed, the source with the largest quasi-allocation amount, which is defined in this article, will be used first. A few literature examples are investigated to show the method proposed. The results show that the method proposed in this work is very simple and the freshwater consumptions of the designs obtained are very close to the minimum freshwater targets.