Silver chalcogenolate cluster assembled materials (SCAMs) are a category of promising light‐emitting materials the luminescence of which can be modulated by variation of their building blocks ...(cluster nodes and organic linkers). The transformation of a singly emissive Ag12(SBut)8(CF3COO)4(bpy)4n (Ag12bpy, bpy=4,4′‐bipyridine) into a dual‐emissive (Ag12(SBut)6(CF3COO)6(bpy)3)n (Ag12bpy‐2) via cluster‐node isomerization, the critical importance of which was highlighted in dictating the photoluminescence properties of SCAMs. Moreover, the newly obtained Ag12bpy‐2 served to construct visual thermochromic Ag12bpy‐2/NH2 by a mixed‐linker synthesis, together with dichromatic core–shell Ag12bpy‐2@Ag12bpy‐NH2‐2 via solvent‐assisted linker exchange. This work provides insight into the significance of metal arrangement on physical properties of nanoclusters.
Tandem varying of Ag cluster structure and tuning mixed linkers in a stepwise fashion are used to achieve dual‐emitting homogeneous and core–shell silver chalcogenolate cluster assembled materials. The arrangements of silver in the cluster are demonstrated to play a fundamentally important role in luminescence.
Silver(i) chalcogenide/chalcogenolate clusters are promising photofunctional materials for sensing, optoelectronics and solar energy harvesting applications. However, their instability and poor ...room-temperature luminescent quantum yields have hampered more extensive study. Here, we graft such clusters to adaptable bridging ligands, enabling their interconnection and the formation of rigid metal-organic frameworks. By controlling the spatial separation and orientation of the clusters, they then exhibit enhanced stability (over one year) and quantum yield (12.1%). Ultrafast dual-function fluorescence switching (<1 s) is also achieved, with turn-off triggered by O
and multicoloured turn-on by volatile organic compounds. Single-crystal X-ray diffraction of the inclusion materials, obtained by single-crystal-to-single-crystal transformation, enables precise determination of the position of the small molecules within the framework, elucidating the switching mechanism. The work enriches the cluster-based metal-organic framework portfolio, bridges the gap between silver chalcogenide/chalcogenolate clusters and metal-organic frameworks, and provides a foundation for further development of functional silver-cluster-based materials.
Lexical data augmentation for sentiment analysis Xiang, Rong; Chersoni, Emmanuele; Lu, Qin ...
Journal of the Association for Information Science and Technology,
November 2021, 2021-11-00, Letnik:
72, Številka:
11
Journal Article
Recenzirano
Odprti dostop
Machine learning methods, especially deep learning models, have achieved impressive performance in various natural language processing tasks including sentiment analysis. However, deep learning ...models are more demanding for training data. Data augmentation techniques are widely used to generate new instances based on modifications to existing data or relying on external knowledge bases to address annotated data scarcity, which hinders the full potential of machine learning techniques. This paper presents our work using part‐of‐speech (POS) focused lexical substitution for data augmentation (PLSDA) to enhance the performance of machine learning algorithms in sentiment analysis. We exploit POS information to identify words to be replaced and investigate different augmentation strategies to find semantically related substitutions when generating new instances. The choice of POS tags as well as a variety of strategies such as semantic‐based substitution methods and sampling methods are discussed in detail. Performance evaluation focuses on the comparison between PLSDA and two previous lexical substitution‐based data augmentation methods, one of which is thesaurus‐based, and the other is lexicon manipulation based. Our approach is tested on five English sentiment analysis benchmarks: SST‐2, MR, IMDB, Twitter, and AirRecord. Hyperparameters such as the candidate similarity threshold and number of newly generated instances are optimized. Results show that six classifiers (SVM, LSTM, BiLSTM‐AT, bidirectional encoder representations from transformers BERT, XLNet, and RoBERTa) trained with PLSDA achieve accuracy improvement of more than 0.6% comparing to two previous lexical substitution methods averaged on five benchmarks. Introducing POS constraint and well‐designed augmentation strategies can improve the reliability of lexical data augmentation methods. Consequently, PLSDA significantly improves the performance of sentiment analysis algorithms.
Elucidating single‐atom effects on the fundamental properties of nanoparticles is challenging because single‐atom modifications are typically accompanied by appreciable changes to the overall ...particle's structure. Herein, we report the synthesis of a Cu58H20PET36(PPh3)42+ (Cu58; PET: phenylethanethiolate; PPh3: triphenylphosphine) nanocluster—an atomically precise nanoparticle—that can be transformed into the surface‐defective analog Cu57H20PET36(PPh3)4+ (Cu57). Both nanoclusters are virtually identical, with five concentric metal shells, save for one missing surface copper atom in Cu57. Remarkably, the loss of this single surface atom drastically alters the reactivity of the nanocluster. In contrast to Cu58, Cu57 shows promising activity for click chemistry, particularly photoinduced 3+2 azide‐alkyne cycloaddition (AAC), which is attributed to the active catalytic site in Cu57 after the removal of one surface copper atom. Our study not only presents a unique system for uncovering the effect of a single‐surface atom modification on nanoparticle properties but also showcases single‐atom surface modification as a powerful means for designing nanoparticle catalysts.
Single‐atom modifications are typically accompanied by appreciable changes to the overall particle's structure. Herein, we demonstrate surface single‐atom manipulation based on Cu58H20PET36(PPh3)42+ (Cu58; PET: phenylethanethiolate; PPh3: triphenylphosphine), leading to the isostructural analogue Cu57H20PET36(PPh3)4+ (Cu57). Remarkably, this single surface atom drastically alters the catalytic reactivity of the nanoclusters.
Modality exclusivity norms have been developed in different languages for research on the relationship between perceptual and conceptual systems. This paper sets up the first modality exclusivity ...norms for Chinese, a Sino-Tibetan language with semantics as its orthographically relevant level. The norms are collected through two studies based on Chinese sensory words. The experimental designs take into consideration the morpho-lexical and orthographic structures of Chinese. Study 1 provides a set of norms for Mandarin Chinese single-morpheme words in mean ratings of the extent to which a word is experienced through the five sense modalities. The degrees of modality exclusivity are also provided. The collected norms are further analyzed to examine how sub-lexical orthographic representations of sense modalities in Chinese characters affect speakers' interpretation of the sensory words. In particular, we found higher modality exclusivity rating for the sense modality explicitly represented by a semantic radical component, as well as higher auditory dominant modality rating for characters with transparent phonetic symbol components. Study 2 presents the mean ratings and modality exclusivity of coordinate disyllabic compounds involving multiple sense modalities. These studies open new perspectives in the study of modality exclusivity. First, links between modality exclusivity and writing systems have been established which has strengthened previous accounts of the influence of orthography in the processing of visual information in reading. Second, a new set of modality exclusivity norms of compounds is proposed to show the competition of influence on modality exclusivity from different linguistic factors and potentially allow such norms to be linked to studies on synesthesia and semantic transparency.
Word embeddings are vectorial semantic representations built with either counting or predicting techniques aimed at capturing shades of meaning from word co-occurrences. Since their introduction, ...these representations have been criticized for lacking interpretable dimensions. This property of word embeddings limits our understanding of the semantic features they actually encode. Moreover, it contributes to the "black box" nature of the tasks in which they are used, since the reasons for word embedding performance often remain opaque to humans. In this contribution, we explore the semantic properties encoded in word embeddings by mapping them onto interpretable vectors, consisting of explicit and neurobiologically motivated semantic features (Binder et al. 2016). Our exploration takes into account different types of embeddings, including factorized count vectors and predict models (Skip-Gram, GloVe, etc.), as well as the most recent contextualized representations (i.e., ELMo and BERT).
In our analysis, we first evaluate the quality of the mapping in a retrieval task, then we shed light on the semantic features that are better encoded in each embedding type. A large number of probing tasks is finally set to assess how the original and the mapped embeddings perform in discriminating semantic categories. For each probing task, we identify the most relevant semantic features and we show that there is a correlation between the embedding performance and how they encode those features. This study sets itself as a step forward in understanding which aspects of meaning are captured by vector spaces, by proposing a new and simple method to carve human-interpretable semantic representations from distributional vectors.
The coronavirus disease 2019 (COVID-19) pandemic has had a considerable impact on US hospitalizations, affecting processes and patient population.
To evaluate the impact of COVID-19 pandemic on ...central-line-associated bloodstream infections (CLABSIs) and catheter associated urinary tract infections (CAUTIs) in hospitals.
We performed a retrospective study of CLABSIs and CAUTIs in 78 US 12 months before COVID-19 and 6 months during COVID-19 pandemic.
During the 2 study periods, there were 795,022 central-line days and 817,267 urinary catheter days. Compared to the period before the COVID-19 pandemic, CLABSI rates increased by 51.0% during the pandemic period from 0.56 to 0.85 per 1,000 line days (P < .001) and by 62.9% from 1.00 to 1.64 per 10,000 patient days (P < .001). Hospitals with monthly COVID-19 patients representing >10% of admissions had a National Health Safety Network (NHSN) device standardized infection ratio for CLABSI that was 2.38 times higher than hospitals with <5% prevalence during the pandemic period (P = .004). Coagulase-negative Staphylococcus CLABSIs increased by 130% from 0.07 to 0.17 events per 1,000 line days (P < .001), and Candida spp by 56.9% from 0.14 to 0.21 per 1,000 line days (P = .01). In contrast, no significant changes were identified for CAUTI (0.86 vs 0.77 per 1,000 catheter days; P = .19).
The COVID-19 pandemic was associated with substantial increases in CLABSIs but not CAUTIs. Our findings underscore the importance of hardwiring processes for optimal line care and regular feedback on performance to maintain a safe environment.
Background and Aim
Tumor progression and distant metastasis are the main causes of deaths in gastric cancer. Growing evidence revealed that circular RNAs (circRNAs) play critical role in the ...pathology of malignant disease, the role of circRNAs in gastric cancer progression and metastasis is still unknown.
Methods
Differentially expressed circRNAs was identified by circRNA microarray and validated by quantitative reverse transcription polymerase reaction. The biological function of circTNIK was evaluated by in vitro and in vivo experiments after ectopic expression or siRNA mediated knockdown of circTNIK. The interaction between circTNIK and miR‐138‐5p was determined by luciferase activity assay, RNA immunoprecipitation, and fluorescence in situ hybridization assays.
Results
circTNIK rather than linear TINK mRNA was significantly upregulated in gastric cancer tissues, cell lines compared with normal controls. Higher circTNIK expression was correlated with aggressive tumor phenotypes and poor overall survival in gastric cancer patients. Ectopic circTNIK expression promoted cell proliferation, invasion, tumorigenesis, and metastasis in gastric cancer cells whereas knockdown of circTNIK inhibited cell proliferation, invasion, tumorigenesis, and metastasis in gastric cancer cells. Importantly, circTNIK functions as a molecular sponge for miR‐138‐5p to regulate the expression of ZEB2.
Conclusions
Overall, our study demonstrates how circTNIK regulates gastric cancer progression and metastasis by sponging miR‐138‐5p to modulate the expression of ZEB2. CircTNIK might be used as a prognostic biomarker in gastric cancer patients.
Convenient generation of stable superatomic silver clusters and their systematic site-specific tailoring and directional assembly present an enduring and significant challenge. In this work, we ...prepared a face-centered cubic (fcc) array of Ag14 superatoms protected by face-capping 1,2-dithiolate-o-carborane (C2B10H10S2) ligands, each produced from 1-thiol-o-carborane in crystallization with simultaneous reduction of Ag+ to Ag0. We find that the corner N-donor ligands contribute predominately to the stability and luminescence of the Ag14 superatom. As the first-formed nanocluster Ag14(C2B10H10S2)6(CH3CN)8·4CH3CN (NC-1) with labile vertex-coordinated CH3CN ligands is highly unstable, monodendate pyridine ligands were used to replace these CH3CN species site-specifically, giving Ag14(C2B10H10S2)6(pyridine/p-methylpyridine)8 (NCs-2,3) in gram scale with its core structure intact, which features ultrastability up to 150 °C in air. Moreover, using bidentate N-containing ligands to bridge the superatomic Ag14 building blocks, we constructed an unprecedented hierarchical series of 1D-to-3D superatomic silver cluster-assembled materials (SCAM-1,2,3,4), and SCAM-4 is air-stable up to 220 °C. Furthermore, this series of stable solid-state superatomic-nanocluster materials exhibit tunable dual emission with wide-range thermochromism. The present study constitutes a major step toward the development of ligand-modulation of the structure, stability, assembly, and functionality of superatomic silver nanoclusters.
Self‐assembly of metavanadate and organosilver(I) salts leads to a novel dodecahedrane‐like Ag30(tBuS)2010+ silver(I) thiolate nanocage that tightly wraps an unusual C2h polyoxovanadate anion. The ...polyoxovanadate core undergoes transformation to a D3d configuration upon acidification, and reverts back to its original C2h structure upon addition of base. Chromism was observed for the silver(I) thiolate cluster during the configurational change of the central polyoxovanadate core; the color of the solution changes reversibly from green to dark yellow. This work represents the first reported example of chromic polyoxometalate‐templated silver(I) thiolate shells that respond to external acid–base stimuli. It also represents an important advance in providing crystallographic proof that structural transformations occur in a nanoscale core–shell cluster.
Silver cage: Self‐assembly of metavanadate and organosilver(I) salts generates a dodecahedrane‐like silver(I) thiolate Ag30(tBuS)2010+ nanocage that tightly wraps a polyoxovanadate core. Single‐crystal X‐ray crystallography was used to show that the core undergoes a reversible C2h to D3d configurational transformation in response to acid/base stimuli, which also result in a color change from green to dark yellow.
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