Ferroelectric Solitons Crafted in Epitaxial Bismuth Ferrite Superlattices

In ferroelectrics, complex interactions among various degrees of freedom enable the condensation of topologically protected polarization textures. Known as ferroelectric solitons, these particle-like structures represent a new class of materials with promise for beyond CMOS technologies due to their ultrafine size and sensitivity to external stimuli. Such polarization textures have scarcely been reported in multiferroics. Here, we report a range of soliton topologies in bismuth ferrite strontium titanate superlattices. High-resolution piezoresponse force microscopy and Cs-corrected high-angle annular dark-field scanning transmission electron microscopy reveal a zoo of topologies, and polarization displacement mapping of planar specimens reveals center-convergent and divergent topological defects as small as 3 nm. Phase field simulations verify that some of these topologies can be classed as bimerons, with a topological charge of plus and minus one, and first-principles-based effective Hamiltonian computations show that the co-existence of such structures can lead to non-integer topological charges, a first observation in a BiFeO3-based system. Our results open new opportunities in multiferroic topotronics

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency–Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Molecular and bioactive profiling of selected Eugenia species from Mauritius Island

The <em>Eugenia</em> genus is comprised of about 1011 species which share similar features resulting in the complexity of its taxonomy and nomenclature. <em>E. crassipetala, E. kanakana, E. tinifolia</em> and two undescribed <em>Eugenia</em> <em>species</em> all medicinal and endemic to Mauritius Islands were characterized using their phytochemical, bioactive and molecular profile. Biological activity was assessed using the broth microdilution assay and the DPPH assay. Significant minimal inhibitory concentration values of <em>E. crassipetala</em> against <em>E. coli</em> (1.56 mg/mL), <em>E. kanakana</em> against <em>P. mirabilis</em> (0.55 mg/mL) and <em>E. spp</em> (small) against <em>S. aureus</em> (0.43 mg/mL) validates the antibacterial ability of these plant extracts and could be attributed to their high content of antioxidants (flavonoids and phenols). Genetic diversity among these five species was assessed by amplification of genomic DNA using 60 RAPD and 25 ISSR markers. Hierarchical cluster analysis validates the uniqueness of each <em>Eugenia</em> species with <em>E. crassipetala</em> and <em>E. tinifolia</em> forming a separate cluster. Comparative analysis of phytochemical composition and bioactivity correlate with the branching pattern of the species in the dendogram

Reading New Black Fiction of South East Asia: An ex-centric approach to transnational literary studies

Responding to critiques of the status quo in transnational literary studies, this essay models an alternative approach, particularly for the field of African–Asian studies. The transnational turn in literary studies has often been less global than we might desire: postcolonial texts are frequently read in terms of predetermined features or ideologies, and comparative studies often posit the USA as their locus for comparison. Following Ato Quayson’s call for attention to the “ex-centric” in postcolonial and transnational literature, this essay demonstrates how the figures of gui and Eshu emerge as interpretative keys in two recent African–Asian works, by Ken Kamoche and Biyi Bandele. The essay argues that these figures point up the complexities inherent in transnational relations, which the texts explore. The essay invites us to read with greater alertness to the “ex-centric” in transnational texts in order to unpack their full implications

Secreted transforming growth factor β2 activates NF-κB, blocks apoptosis, and is essential for the survival of some tumor cells

The basis of constitutive activation of NF-κB, essential for survival and resistance to apoptosis in many tumors, is not well understood. We find that transforming growth factor β2 (TGFβ2), predominantly in its latent form, is secreted by several different types of tumor cell lines that exhibit constitutively active NF-κB and that TGFβ2 potently stimulates the activation of NF-κB in reporter cells. Suppression of TGFβ2 expression by small interfering RNA kills prostate cancer PC3 cells, indicating that the TGFβ2–NF-κB pathway is important for their viability. These findings identify TGFβ2 as a potential target for therapeutic strategies to inhibit the growth of tumor cells that depend on constitutively active NF-κB, or to sensitize them to treatment with cytotoxic drugs