The response rates of online surveys were often examined in the literature by comparing to other modes of surveys. Questions regarding what constitutes a respectable response rate for online surveys ...in research remained unanswered. To fill in the knowledge gap, we conducted a comprehensive search, screened 8672 studies, and examined 1071 online survey response rates reported in education-related research. Our analyses showed the number of online surveys in published research grew steadily across the years. The average online survey response rate is 44.1%. Our results indicate that sending an online survey to more participants did not generate a higher response rate. Instead, sending surveys to a clearly defined and refined population positively impacts the online survey response rate. In addition, pre-contacting potential participants, using other types of surveys in conjunction with online surveys, and using phone calls to remind participants about the online survey could also yield a higher response rate. The use of incentives did not show a significant impact on the response rate of online surveys. Other factors that impacted the rates included the funding status of a project, and the age and occupation of the participants. Concrete suggestions for reviewing and improving the online survey response rates are provided.
We describe pLink 2, a search engine with higher speed and reliability for proteome-scale identification of cross-linked peptides. With a two-stage open search strategy facilitated by fragment ...indexing, pLink 2 is ~40 times faster than pLink 1 and 3~10 times faster than Kojak. Furthermore, using simulated datasets, synthetic datasets,
N metabolically labeled datasets, and entrapment databases, four analysis methods were designed to evaluate the credibility of ten state-of-the-art search engines. This systematic evaluation shows that pLink 2 outperforms these methods in precision and sensitivity, especially at proteome scales. Lastly, re-analysis of four published proteome-scale cross-linking datasets with pLink 2 required only a fraction of the time used by pLink 1, with up to 27% more cross-linked residue pairs identified. pLink 2 is therefore an efficient and reliable tool for cross-linking mass spectrometry analysis, and the systematic evaluation methods described here will be useful for future software development.
Dendrobium is known for its pharmacological actions including anti-cancer effect, anti-fatigue effect, gastric ulcer protective effect, and so on. At present, only studies on endophytic fungi of ...Dendrobium affecting the metabolites of host plants have been reported, very little research has been done on endophytic bacteria. In this study, we have demonstrated the great diversity of endophytic bacteria in 6 Dendrobium samples from different origins and cultivars. According to the results of the culture-independent method, the endophytic bacterial community in Dendrobium stems showed obvious different in the 6 samples and was influenced by origin and cultivar. Some bacteria including Ralstonia, Comamonas and Lelliottia were first detected in Dendrobium in this study. Based on the culture-dependent method, a total of 165 cultivable endophytic bacteria isolates were isolated from the sterilized Dendrobium stems, and were classified into 43 species according to the 16S rRNA gene sequence analysis. Moreover, 14 of the 43 strains showed antimicrobial activity against phytopathogen using the Kirby-Bauer method. Strain NA-HTong-7 (Bacillus megaterium, 99.12%) showed the highest antimicrobial activity. This study was the first comprehensive study on endophytic bacteria of Dendrobium from different origins and cultivars, which provides new insights into the endophytic bacteria from Dendrobium.
Heavy‐atom‐containing clusters, nanocrystals, and other semiconductors can sensitize the triplet states of their surface‐bonded chromophores, but the energy loss, such as nonradiative deactivation, ...often prevents the synergistic light emission in their solid‐state coassemblies. Cocrystallization allows new combinations of molecules with complementary properties for achieving functionalities not available in single components. Here, the cocrystal formation that employs platinum(II) acetylacetonate (Pt(acac)2) as a triplet sensitizer and electron‐deficient 1,4,5,8‐naphthalene diimides (NDIs) as organic phosphors is reported. The hybrid cocrystals exhibit room‐temperature phosphorescence confined in the low‐lying, long‐lived triplet state of NDIs with photoluminescence (PL) quantum yield (ΦPL) exceeding 25% and a phosphorescence lifetime (τPh) of 156 µs. This remarkable PL property benefits from the noncovalent electronic and spin–orbital coupling between the constituents.
A cocrystallization strategy is developed to enable efficient room‐temperature phosphorescence confined in the organic dye with a remarkable photoluminescence quantum yield of 25.1 ± 1%. This strategy to brighten the triplet state of organic chromophores may be quite general and open up a new avenue for designing innovative phosphorescent materials.
Abstract
Metal halide perovskites have emerged as promising candidates for solution-processed blue light-emitting diodes (LEDs). However, halide phase segregation – and the resultant spectral shift – ...at LED operating voltages hinders their application. Here we report true-blue LEDs employing quasi-two-dimensional cesium lead bromide with a narrow size distribution of quantum wells, achieved through the incorporation of a chelating additive. Ultrafast transient absorption spectroscopy measurements reveal that the chelating agent helps to control the quantum well thickness distribution. Density functional theory calculations show that the chelating molecule destabilizes the lead species on the quantum well surface and that this in turn suppresses the growth of thicker quantum wells. Treatment with γ-aminobutyric acid passivates electronic traps and enables films to withstand 100 °C for 24 h without changes to their emission spectrum. LEDs incorporating γ-aminobutyric acid-treated perovskites exhibit blue emission with Commission Internationale de l'Éclairage coordinates of (0.12, 0.14) at an external quantum efficiency of 6.3%.
Spectrum sensing, which aims at detecting spectrum holes, is the precondition for the implementation of cognitive radio (CR). Collaborative spectrum sensing among the cognitive radio nodes is ...expected to improve the ability of checking complete spectrum usage. Due to hardware limitations, each cognitive radio node can only sense a relatively narrow band of radio spectrum. Consequently, the available channel sensing information is far from being sufficient for precisely recognizing the wide range of unoccupied channels. Aiming at breaking this bottleneck, we propose to apply matrix completion and joint sparsity recovery to reduce sensing and transmission requirements and improve sensing results. Specifically, equipped with a frequency selective filter, each cognitive radio node senses linear combinations of multiple channel information and reports them to the fusion center, where occupied channels are then decoded from the reports by using novel matrix completion and joint sparsity recovery algorithms. As a result, the number of reports sent from the CRs to the fusion center is significantly reduced. We propose two decoding approaches, one based on matrix completion and the other based on joint sparsity recovery, both of which allow exact recovery from incomplete reports. The numerical results validate the effectiveness and robustness of our approaches. In particular, in small-scale networks, the matrix completion approach achieves exact channel detection with a number of samples no more than 50% of the number of channels in the network, while joint sparsity recovery achieves similar performance in large-scale networks.
Thermal‐responsive phosphorescent nanotubes have been fabricated from the co‐assembly of two neutral iridium complexes, which behave as the antenna chromophores and energy acceptors, respectively, in ...these highly ordered crystalline superstructures. By tuning the acceptor doping ratio in a range of 0 to 0.5 %, these tubes display color‐tunable phosphorescence from green to red at room temperature, and it is attributed to the highly efficient light‐harvesting and energy transfer within these materials. For the same reason, the acceptor emission in the nanotubes is amplified more than 800 times with respect to its pure non‐emissive solid sample. The doped tubes show reversible thermal‐responsiveness, in which the energy transfer was completely suppressed at 77 K and reactivated at room temperature. These processes were characterized by the in situ emission color (green, orange, and red) and spectral changes and lifetime measurements of isolated nanotubes. The temperature‐controlled exciton dynamics are responsible for the luminescent thermochromism in these crystalline materials.
With flying colors: The co‐assembly of two neutral iridium complexes gives rise to crystalline phosphorescent nanotubes with highly efficient light‐harvesting and energy‐transfer properties. They display color‐tunable and thermal‐responsive phosphorescence from green to red at a low acceptor doping ratio of less than 0.2 %. The acceptor emission in the crystalline nanotubes is amplified more than 800 times with respect to its non‐emissive pure solid sample.
Metal borides/borates have been considered promising as oxygen evolution reaction catalysts; however, to date, there is a dearth of evidence of long-term stability at practical current densities. ...Here we report a phase composition modulation approach to fabricate effective borides/borates-based catalysts. We find that metal borides in-situ formed metal borates are responsible for their high activity. This knowledge prompts us to synthesize NiFe-Boride, and to use it as a templating precursor to form an active NiFe-Borate catalyst. This boride-derived oxide catalyzes oxygen evolution with an overpotential of 167 mV at 10 mA/cm
in 1 M KOH electrolyte and requires a record-low overpotential of 460 mV to maintain water splitting performance for over 400 h at current density of 1 A/cm
. We couple the catalyst with CO reduction in an alkaline membrane electrode assembly electrolyser, reporting stable C
H
electrosynthesis at current density 200 mA/cm
for over 80 h.
In this paper, we put forward a novel approach for change detection in synthetic aperture radar (SAR) images. The approach classifies changed and unchanged regions by fuzzy c-means (FCM) clustering ...with a novel Markov random field (MRF) energy function. In order to reduce the effect of speckle noise, a novel form of the MRF energy function with an additional term is established to modify the membership of each pixel. In addition, the degree of modification is determined by the relationship of the neighborhood pixels. The specific form of the additional term is contingent upon different situations, and it is established ultimately by utilizing the least-square method. There are two aspects to our contributions. First, in order to reduce the effect of speckle noise, the proposed approach focuses on modifying the membership instead of modifying the objective function. It is computationally simple in all the steps involved. Its objective function can just return to the original form of FCM, which leads to its consuming less time than that of some obviously recently improved FCM algorithms. Second, the proposed approach modifies the membership of each pixel according to a novel form of the MRF energy function through which the neighbors of each pixel, as well as their relationship, are concerned. Theoretical analysis and experimental results on real SAR datasets show that the proposed approach can detect the real changes as well as mitigate the effect of speckle noises. Theoretical analysis and experiments also demonstrate its low time complexity.
Polymorphism and anisotropy are fundamental phenomena of crystalline materials. However, the structure-dependent photoluminescent (PL) anisotropy in polymorphic organic crystals has remained ...unexplored. Herein, two polymorphic nanocrystals, green-emitting nanorods (PtD-g) and yellow-emitting nanoplates (PtD-y), were obtained from a platinum(II)−β-diketonate complex. The PtD-y crystals display remarkable PL anisotropy with an anisotropy ratio of up to 0.87 whereas the emission of the PtD-g crystals is nearly unpolarized. The polarization properties are rationalized on the different molecular packing of these crystals. By light-harvesting energy transfer, the PtD-y crystals are successfully used to amplify the emission polarization of a red-emitting platinum acceptor (PtA) doped into the donor crystalline matrix, which is otherwise weakly polarized as pure crystals.
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