Cooper-pair distribution function $$D_{cp}(\omega ,T_c)$$ for superconducting $$\hbox {D}_3\hbox {S}$$ and $$\hbox {H}_3\hbox {S}$$

Cooper-pair distribution function, $$D_{cp}(\omega ,T_c)$$ D cp ( ω , T c ) , is a recent theoretical proposal that reveals information about the superconductor state through the determination of the spectral regions where Cooper pairs are formed. This is built from the well-established Eliashberg spectral function and phonon density of states, calculated by first-principles. From this function is possible to obtain the $$N_{cp}$$ N cp parameter, which is proportional to the total number of Cooper pairs formed at a critical temperature $$T_c$$ T c . Herein, we reported $$D_{cp}(\omega ,T_c)$$ D cp ( ω , T c ) function of the compressed $$D_3S$$ D 3 S and $$H_3S$$ H 3 S high-$$T_c$$ T c conventional superconductors, including the effect of stable sulfur isotopes in $$H_3S$$ H 3 S . $$D_{cp}(\omega ,T_c)$$ D cp ( ω , T c ) suggests that the vibration energy range of 10–70 meV is where the Cooper pairs are possible for these superconductors, pointing out the possible importance of the low-energy region on the electron–phonon superconductivity. This has been confirmed by the fact that a simple variation in the low-frequency region induced for the substitution of S atoms in $$H_3S$$ H 3 S by its stable isotopes can lead to important changes in $$T_c$$ T c . The results also show proportionality between $$N_{cp}$$ N cp parameter and experimental or theoretical $$T_c$$ T c values.

Superscattering for non-spherical objects

In this work we generalize the notion of superscattering and associate it with a symmetry group of a scattering object. Using the group theory approach we describe a way to spectrally overlap several eigenmodes of a resonator in order to achieve scattering enhancement. Importantly, this can be done by simple variation of geometric parameters of the system, implying that the symmetry is preserved. We also demonstarte that a scattering cross-section limit of a spherical object is not valid for the case of non-spherical geometries. As an example, we use finite-size ceramic cylinder and demonstrate that a dipolar scattering cross-section limit of a spherical object can be exceeded by more then 3 times. The obtained results may be promising for design of antennas and radio frequency identification systems.

Adapting to the New Normal During the COVID-19 Pandemic Through Creating a Children's Song With a Health Theme

Health promotion activities are crucial amid the COVID-19 pandemic. Health promotion can be carried out through various methods, one of which is through musical activities. Musical activities may trigger a community’s awareness of the government’s programs related to minimizing the spread of COVID-19. The spread of COVID-19 reminds us that healthy behavior should be internalized as early as possible. The use of children’s songs as a medium of health education serves to promote healthy and clean-living behavior. Song creation for school-aged children could be an educational model to maintain personal and environmental health. In this study, data were collected through a literature review and observations of health-related issues for children. The song was created by determining the listener (i.e. children), the theme for adaptation to the new normal era (healthy behaviors), and the structure (AA, AB with simple variation of ABA, AAB); making the lyrics, a simple melody, and the song title; and writing in notation and socializing. The result of the study was a children’s song with a health theme, specifically related to healthy behaviors for adapting to the new normal, which can serve as a medium of health education for children. Keywords: health education, song creation, children’s song, adaptation to new normal

N-heterocyclic carbene-metal complexes as bio-organometallic antimicrobial and anticancer drugs, an update (2015–2020)

N-heterocyclic carbenes (NHCs) are organic compounds that typically mimic the chemical properties of phosphines. NHCs have made a significant impact on the field of coordination and organometallic chemistry because they are easy to prepare and handle and because of their versatility and stability. Importantly, the physicochemical properties of NHCs can be easily fine-tuned by simple variation of substituents on the nitrogen atoms. Over the past few years, various NHC–metal complexes have been extensively used as metal-based drug candidates and catalysts (homogeneous or heterogeneous) for various applications. To help assist future work with these compounds, this review provides a thorough review on the latest information involving some biomedical applications of NHC–metal complexes. Specifically, this article focuses on recent advances in the design, synthesis, characterization and biomedical applications (e.g., antimicrobial and anticancer activity) of various NHC–metal complexes (metal: silver, gold, palladium, rhodium, ruthenium, iridium and platinum) covering work published from 2015 to 2020. It is hoped that the promising discoveries to date will help accelerate studies on the encouraging potential of NHC–metal complexes as a class of effective therapeutic agents.

New Quinoline-Based Heterocycles as Anticancer Agents Targeting Bcl-2

The Bcl-2 protein has been studied as an anticancer drug target in recent years, due to its gatekeeper role in resisting programmed cancer cell death (apoptosis), and the design of BH3 domain mimetics has led to the clinical approval of Venetoclax (ABT-199) for the treatment of chronic lymphocytic leukaemia. In this work we extend our previous studies on the discovery of indole-based heterocycles as Bcl-2 inhibitors, to the identification of quinolin-4-yl based oxadiazole and triazole analogues. Target compounds were readily synthesized via a common aryl-substituted quinolin-4-carbonyl-N-arylhydrazine-1-carbothioamide (5a–b) intermediate, through simple variation of the basic cyclisation conditions. Some of the quinoline-based oxadiazole analogues (e.g. compound 6i) were found to exhibit sub-micromolar anti-proliferative activity in Bcl-2-expressing cancer cell lines, and sub-micromolar IC50 activity within a Bcl2-Bim peptide ELISA assay. The Bcl-2 targeted anticancer activity of 6i was further rationalised via computational molecular modelling, offering possibilities to extend this work into the design of further potent and selective Bcl-2 inhibitory heteroaromatics with therapeutic potential.

Motile curved bacteria are Pareto-optimal

Curved-rods are a ubiquitous bacterial phenotype, but the fundamental question of why they are shaped this way remains unanswered. Throughin silicoexperiments, we assessed freely swimming straight- and curved-rod bacteria of a wide diversity of equal-volume shapes parameterized by elongation and curvature, and predicted their performances in tasks likely to strongly influence overall fitness. Performance tradeoffs between these tasks lead to a variety of shapes that are Pareto-optimal, including coccoids, all straight rods, and a range of curvatures. Comparison with an extensive morphological survey of motile curved-rod bacteria indicates that the vast majority of species fall within the Pareto-optimal region of morphospace. This result is consistent with evolutionary tradeoffs between just three tasks: efficient swimming, chemotaxis, and low cell construction cost. We thus reveal the underlying selective pressures driving morphological diversity in a wide-spread component of microbial ecosystems.Significance StatementBacteria exhibit a bewildering diversity of morphologies but despite their impact on nearly all aspects of life, they are frequently classified into a few general categories, usually just ‘spheres’ and ‘rods’. Curved-rod bacteria are one simple variation and are widespread, particularly in the ocean. However, why so many species have evolved this shape is unknown. We show that curvature can increase swimming efficiency, revealing a widely-applicable selective advantage. Furthermore, we show that the distribution of cell lengths and curvatures observed across bacteria in nature are predicted by evolutionary tradeoffs between three tasks influenced by shape: efficient swimming, the ability to detect chemical gradients, and reduced cost of cell construction. We therefore reveal shape as an important component of microbial fitness.

Clifford’s attempt to test his gravitation hypothesis

Almost half a century before Einstein expounded his general theory of relativity, the English mathematicianWilliam Kingdon Clifford argued that space might not be Euclidean and proposed that matter is nothing but a small distortion in that spatial curvature. He further proposed that matter in motion is not more than the simple variation in space of this distortion. In this work, we conjecture that Clifford went further than his aforementioned proposals, as he tried to show that matter effectively curves space. For this purpose he made an unsuccessful observation on the change of the plane of polarization of the skylight during the solar eclipse of December 22, 1870 in Sicily.

Cocconeis scutellum var. parva (Bacillariophyceae) re-examination and typification

Electron microscope (EM) is essential for the morphological description of small taxa, but also reveals taxa hitherto grouped under the same name although presenting marked ultrastructural differences: e.g., Cocconeis scutellum var. parva. The latter taxon has been interpreted differently by authors, while no type has been examined since the original description. A slide from the Grunow’s collection in W, annotated by Albert Grunow as containing C. scutellum var. parva was examined and detailed for the first time. This slide allowed for a more precise definition of C. scutellum var. parva and is here designated as lectotype. This paper analyzes the history of C. scutellum var. parva and attempts to exclude definitions that are too far from the original drawings and from the lectotype illustration. A tropical–population from Rodrigues Island (Indian Ocean) composed of small specimens with stria densities significantly denser than observed on the nominate variety, is here described as an epitype of C. scutellum var. parva and is illustrated with SEM. A small taxon from Tahiti Island (South Pacific Ocean), seemingly close to C. scutellum var. parva, has unique raphe valve valvocopula with cupuliform papillae. The latter specificity is considered a simple variation and may illustrate the range of morphological variability admitted for a taxon.