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Voltage loading-induced change in the electroluminescence (EL) wavelength of mixed halide perovskite light-emitting diodes (PeLEDs), so-called color-shift, has become an inevitable phenomenon, which is seriously unfavorable to their applications in lighting and display. Here, we achieve color-stable blue PeLEDs via a hydrogen-bonded amine-group doping strategy. Selecting guanidine (GA) or formamidinium (FA) as amine-group (−NH2) doping source for CsPbBrxCl3−x quantum dots (QDs), experimental and theoretical results reveal that the strong N−H⋯X (X = Br/Cl) bonding can be produced between −NH2 dopants and Pb−X lattices, thereby increasing the migration barrier of halide anions. Resultantly, color-stable sky-blue devices were realized with emission peaks fixed at 490.5 (GA) and 492.5 (FA) nm without any obvious shift as the voltage increases, in sharp contrast devices without N−H⋯X producing a 15 nm red-shift from 487 to 502 nm. Not only that, maximum external quantum efficiency is improved to 3.02% and 4.14% from the initial 1.3%. This finding offers a convenient boulevard to achieve color-stable PeLEDs with high efficiency.

We surveyed the practices and abilities of 103 students at 4 universities in China to write from sources in English, documenting in their first and second years of Bachelors’ and Masters’ programs (longitudinally and cross-sectionally): (a) students’ self-reported approaches to writing from sources and instruction that had helped them; (b) the frequency, accuracy, and functions of citations in samples of their course papers; and (c) their abilities to summarize a reading passage under test-like conditions. The students wrote with some proficiency in English and emerging competencies in writing from academic sources, confirming, in this context where English is a foreign language, tendencies such as nascent senses of authorial identities and patchwriting documented in prior case studies of Chinese and other students writing at English-dominant universities internationally. Limited evidence for development from the first to second year appeared in undergraduate students increasing the frequency, accuracy, and functions of their citations, moving toward the tendencies maintained by graduate students in both years’ course papers. In their second years, most students also reported greater success in acknowledging source materials and focus on formal aspects of writing course papers. Only half the students indicated they had taken courses that helped them to write from sources.

Understanding of mechanisms through which arbuscular mycorrhizal fungi (AMF) facilitate establishment and growth of exotic species is important in invasion ecology. We have poor understanding of mechanisms that mediate positive or negative impact of AMF to exotic or native species. We ask whether the quantitative and or qualitative differences in the AMF colonization to exotic Flaveria bidentis and native Setaria viridis provide competitive advantage to the invader over native species. Flaveria bidentis, a native of South America, is an aggressive invader in North China. Native S. viridis is widely distributed in farmlands, roadsides and wastelands, and also found in Flaveria bidentis invaded areas. We hypothesize that exotic species alter AMF composition, which facilitate the establishment and growth of exotic species and reduces the competitiveness of native species. Experiments were carried out to: (i) quantify AMF colonization in roots of field-grown F. bidentis or S. viridis, (ii) isolate DNA sequences of AMF species from roots and soils of exotic F. bidentis and native S. viridis to carry out phylogenetic studies, and (iii) study the effect of AMF Rhizophagus intraradices spores on the physiological performance traits of both exotic F. bidentis and native S. viridis. Our results suggest that certain AMF clones had higher colonization (85%) in roots of F. bidentis than S. viridis (21.1%). AMF-inoculation (130 spores per 100 g soil) enhanced the net photosynthetic rate in the native S. viridis when grown in monoculture but reduced its net photosynthetic rate when grown in competition with exotic F. bidentis. A lower corrected index of relative competition intensity in exotic F. bidentis, and higher levels of foliar nutrient accumulation was observed in response to AMF inoculation than native S. viridis. We show that higher AMF colonization in F. bidentis provides competitive advantage over native S. viridis. This study is important because it establishes the impact of AMF colonization on physiological and ecological performance of the invader.

Metal halide perovskites (MHPs) are received widespread attention due to their high photoluminescence quantum yield (PLQY), narrow emission linewidths, tunable emission colors, and low cost. However, the non-radiative recombination loss caused by defects is a bottleneck restricting the efficiency improvement of MHP-based light-emitting diodes (PeLEDs). In this review, initially, we summarize characteristics of typical defect types that cause PeLEDs efficiency degradation, and demonstrate the effect on the carrier recombination mechanism. Then, we highlight the recent progress of typical defect suppression strategies for obtaining highly efficient PeLEDs, including crystal growth regulation, composition engineering, passivation and dimensional regulation. Finally, we look forward to the future development direction and make suggestions for how to further improve device efficiency. This review is expected to promote the development of PeLEDs and provide a significance guidance for fabricating highly efficient devices.

Surface layers, referred simply as S-layers, are the two-dimensional crystalline arrays of protein or glycoprotein subunits on cell surface. They are one of the most common outermost envelope components observed in prokaryotic organisms (Archaea and Bacteria). Over the past decades, S-layers have become an issue of increasing interest due to their ubiquitousness, special features and functions. Substantial work in this field provides evidences of an enormous diversity in S-layers. This paper reviews and illustrates the diversity from several different aspects, involving the S-layer-carrying strains, the structure of S-layers, the S-layer proteins and genes, as well as the functions of S-layers.

Voice is an important topic in second language writing research and pedagogy, but there have been limited attempts to understand the voice of second language writers from diverse backgrounds. This article aims to achieve a thorough and up-to-date understanding of Chinese students’ voice in English academic writing by adopting a holistic and dynamic perspective to examine factors influencing Chinese students’ voice. The article first critiques previous claims about the negative, deterministic influence of traditional Chinese culture and language on students’ voice and adopts a more positive and agentive view of voice in relation to language and culture. Then it moves on to analyze the influence of various educational factors on Chinese students’ voice development, which has largely been overlooked in previous discussion on this topic. After examining how the dynamic changes in Chinese culture, language, and education in a globalized society may impact Chinese students’ voice development, the article further suggests that these broader contextual factors interact with the more immediate context of writing to shape the complexity of Chinese students’ voice in English. This work has implications for curriculum, pedagogy, and teacher development in various writing contexts.

The purpose of this study was to test an integrative model in which peer relations at different levels of social complexity (friendship quality, social preference, and proximity prestige) are associated with children's loneliness, with children's self-perceived social competence acting as a mediator of these associations. A middle childhood sample of 509 Chinese children (233 girls and 276 boys; 3rd to 6th grade) completed a battery of sociometric and self-report questionnaires. Bootstrap analysis showed that self-perceived social competence mediated the relations between each peer variable and loneliness. In the integrative model tested with SEM, the mediating effect of self-perceived social competence in the relation between friendship quality and loneliness and between social preference and loneliness remained significant. However, self-perceived social competence no longer mediated the association between proximity prestige and loneliness, when considering the simultaneous influences of the three peer variables (friendship quality, social preference, and proximity prestige). The whole model accounted for 56% of the variance in loneliness. These findings suggest that self-perceived social competence played an important role in children's loneliness, that the quality and the quantity of direct peer relations (friendship quality, social preference, and part of proximity prestige) were associated with loneliness, and that indirect friends had a relatively lower but significant influence on children's loneliness. The results are discussed in terms of their implications for preventing children's loneliness.

Detecting avian influenza virus (AIV) and Newcastle disease virus (NDV) at low concentrations from tracheal and cloacal swabs of avian influenza- and Newcastle disease-infected poultry was carried out using a highly sensitive immunological-polymerase chain reaction (immuno-PCR) method. Magnetic gold particles were pre-coated with a capture antibody, either a monoclonal anti-AIV/H5 or monoclonal anti-NDV/F and viruses serially diluted ten-fold from 102 to 10−5 EID50/ml. A biotinylated detection antibody bound to the viral antigen was then linked via a streptavidin bridge to biotinylated reporter DNA. After extensive washing, reporter DNA was released by denaturation, transferred to PCR tubes, amplified, electrophoresed and visualized. An optimized immuno-PCR method was able to detect as little as 10−4 EID50/ml AIV and NDV. To further evaluate the specificity and the clinical application of this IPCR assay for AIV H5N1 and NDV, the tracheal swab specimens, taken from chickens which were infected with H5N1/AIV, H9N2/AIV, H7N2/AIV, NDV, IBDV, IBV/H120, were detected by IPCR. Our data demonstrated that this monoclonal antibody-based immuno-PCR method provides a platform capable of rapid screening of clinical samples for trace levels of AIV H5 and NDV in one step.