bluuebunny/crossref_metadata_2025 huggingface dataset:
An ab initio effective solid-state photoluminescence by frequency constraint of cluster calculation
Authors: Karim Akib , Lyskov Igor , Russo Salvy P. , Peruzzo Alberto
Published: December 2020

Measuring the photoluminescence of defects in crystals is a common experimental technique for analysis and identification. However, current theoretical simulations typically require the simulation of a large number of atoms to eliminate finite-size effects, which discourages computationally expensive excited state methods. We show how to extract the room-temperature photoluminescence spectra of defect centers in bulk from an ab initio simulation of a defect in small clusters. The finite-size effect of small clusters manifests as strong coupling to low frequency vibrational modes. We find that removing vibrations below a cutoff frequency determined by constrained optimization returns the main features of the solid-state photoluminescence spectrum. This strategy is illustrated for the negatively charged nitrogen vacancy defect in diamond (NV−) presenting a connection between defects in solid state and clusters; the first vibrationally resolved ab initio photoluminescence spectrum of an NV− defect in a nanodiamond; and an alternative technique for simulating photoluminescence for solid-state defects utilizing more accurate excited state methods.
Low-power wavelength modulation in size-controlled Si nanocrystals using quantum confined Stark effect
Authors: Yazicioglu Deniz , Gutsch Sebastian , Zacharias Margit
Published: December 2020

We report on the quantum confined Stark effect coupled with a permanent built-in electric dipole moment in size-controlled Si nanocrystals (SiNCs) investigated under steady state conditions by photoluminescence spectroscopy. The study was conducted on samples with SiNC layer thicknesses between 2 nm and 5 nm. The emission spectra of the samples subjected to electric field magnitudes of up to 5 × 108 V/m were analyzed in terms of the dependency of the spectral shift on field magnitude and SiNC size. A clear trend of red shift along with increasing dipole separation was observed with increasing SiNC size. Experimental results show a high degree of accuracy to the model based on the time independent perturbation theory approximation for a biased quantum well. We propose a potential application for size-controlled SiNCs in photon detection in the near infrared band based on the studied phenomena as well as the use of SiNCs as a model platform for further study of the Stark effect in quantum confined structures as a whole.
Redox flow batteries: role in modern electric power industry and comparative characteristics of the main types
Authors: Petrov Mikhail M. , Modestov Alexander D. , Konev Dmitriy V. , Antipov Anatoly E. , Loktionov Pavel A. , Pichugov Roman D. , Kartashova Natalya V. , Glazkov Artem T. , Abunaeva Lilia Z. , Andreev Vladimir N. , Vorotyntsev Mikhail A.
Published: December 2020

In recent years, the key principles of the electric power industry have radically changed and the number of studies on the development of devices for electrical energy storage in a different form such as mechanical or chemical energy has rapidly increased. This review gives a brief description of these devices. The attention is focused on redox flow batteries (RFBs), a promising type of energy storage devices capable of efficiently operating in distributed power grids, in order to eliminate the imbalance between the time-varying electricity production by ‘unconventional sources’ and electricity consumption. At the design level, RFBs combine the principles of fuel cells and chemical energy sources with solid electroactive materials: transitions between electrical and chemical forms of energy in these devices occur upon oxidation and reduction of redox-active electrolytes, which are stored in separate tanks and pumped into the electrode compartments of the membrane electrode assembly (MEA) separated by a semi-permeable membrane. This approach ensures an important advantage of these devices over other types of chemical energy sources, that is, the possibility of independent scaling of the energy storage capacity and power characteristics of the system. This review provides a systematic description of the main types of RFBs and analysis of their fundamental benefits and drawbacks, which determine the prospects for practical applications of RFBs.

The bibliography includes 149 references.
Global tree-ring analysis reveals rapid decrease in tropical tree longevity with temperature
Authors: Locosselli Giuliano Maselli , Brienen Roel J. W. , Leite Melina de Souza , Gloor Manuel , Krottenthaler Stefan , Oliveira Alexandre A. de , Barichivich Jonathan , Anhuf Dieter , Ceccantini Gregorio , Schöngart Jochen , Buckeridge Marcos
Published: December 2020

Significance

This study highlights previously unknown patterns of tree longevity and growth across the world. Tree-ring data reveal a large-scale trade-off between tree longevity and growth, following global patterns of increasing forest productivity and biomass turnover rate from temperate to tropical regions. The oldest known trees live under dry conditions in temperate and boreal zones, while in the dry tropical lowlands, trees only reach relatively short lifespans. Longevity of tropical trees also sharply decreases above mean annual temperatures of 25.4 °C. Thus, predicted future changes in moisture availability and increases in temperature have the potential to reduce tree longevity in tropical lowlands impacting carbon stocks.
Efficient photoactivatable Dre recombinase for cell type-specific spatiotemporal control of genome engineering in the mouse
Authors: Li Huiying , Zhang Qiansen , Gu Yiran , Wu Yingyin , Wang Yamei , Wang Liren , Feng Shijie , Hu Yaqiang , Zheng Yansen , Li Yongmei , Ye Haifeng , Zhou Bin , Lin Longnian , Liu Mingyao , Yang Huaiyu , Li Dali
Published: December 2020

Significance

Precisely defining specific cell types is critical but challenging for biological studies. Site-specific tyrosine-recombinase Cre and its inducible variants have been widely used in efficient genetic engineering. However, a single recombinase system has technical hurdles. Here, a photoactivatable Dre (PA-Dre) recombinase is developed by tethering split Dre fragments to the light-inducible Magnets system. PA-Dre is efficient and stringently controlled in vitro and in vivo. Moreover, with the creation of the Cre-activated light-inducible Dre system, it is able to achieve bulk or sparse labeling of specific neurons in a spatiotemporal manner. This flexible and tunable system could be adapted to a wide range of biological systems for the modulation of developmental and genetic complexity.
Identification of Z nucleotides as an ancient signal for two-component system activation in bacteria
Authors: Vázquez-Ciros Oscar J. , Alvarez Adrián F. , Georgellis Dimitris
Published: December 2020

Significance

Bacterial two-component system signaling circuits (TCSs), comprising sensor histidine kinase (HK) and response regulator (RR) proteins, regulate numerous cellular processes in response to environmental or metabolic cues. Phosphorylation, and thereby activation, of RRs is promoted by their cognate HKs but also by low molecular weight phosphodonors. Here, we report that the purine and histidine biosynthetic intermediates ZMP (AICAR) and/or ZTP act as direct phosphodonors to a wide range of RRs in vivo, thereby modulating the activity of many TCS pathways without the necessity of intervention of an HK. The attainment of this reaction confers an additional function for these ancient molecules to serve as global regulators for gene expression.
The ABL2 kinase regulates an HSF1-dependent transcriptional program required for lung adenocarcinoma brain metastasis
Authors: Hoj Jacob P. , Mayro Benjamin , Pendergast Ann Marie
Published: December 2020

Significance

Among all cancer types, lung cancer patients exhibit the highest prevalence of brain metastasis, often associated with cognitive impairment, seizures, decline in quality of life, and decreased survival. Limited therapeutic options are currently available to treat brain metastasis. A comprehensive understanding of the signaling pathways and transcriptional networks required for survival and growth of brain-metastatic cancer cells is needed to develop effective strategies to treat this disease. Here, we report that the Heat Shock Transcription Factor 1 (HSF1) is upregulated in brain-metastatic lung cancer cells and is required for brain metastasis in mice. Importantly, we show that the HSF1-dependent expression of E2F target genes implicated in cell cycle progression and survival is decreased by blood–brain barrier-penetrant ABL allosteric inhibitors.
Towards the molecular architecture of the peroxisomal receptor docking complex
Authors: Lill Pascal , Hansen Tobias , Wendscheck Daniel , Klink Bjoern Udo , Jeziorek Tomasz , Vismpas Dimitrios , Miehling Jonas , Bender Julian , Schummer Andreas , Drepper Friedel , Girzalsky Wolfgang , Warscheid Bettina , Erdmann Ralf , Gatsogiannis Christos
Published: December 2020

Significance

Peroxisomal matrix enzymes are synthesized in the cytosol and carry targeting signals. These are recognized and bound by an import receptor in the cytosol. The cargo-loaded receptor further binds to the “docking” complex at the peroxisomal membrane. The docking events are expected to trigger the formation of a transient pore allowing import of the cargo into the peroxisomal matrix. Here using cryoelectron microscopy complemented by native MS, cross-linking MS, SEC MALS, and immunogold labeling, we provide the structural characterization of the major components of the yeast peroxisomal docking complex. Pex14p/Pex17p assemble in a parallel 3:1 bundle arrangement to form intriguingly long flexible rods that emanate into the cytosol to recruit the cargo-loaded receptor for further translocation events.
An in vivo atlas of host–pathogen transcriptomes during
Streptococcus pneumoniae
colonization and disease
Authors: D’Mello Adonis , Riegler Ashleigh N. , Martínez Eriel , Beno Sarah M. , Ricketts Tiffany D. , Foxman Ellen F. , Orihuela Carlos J. , Tettelin Hervé
Published: December 2020

Significance

We detail host–pathogen interaction gene-expression profiles of
Streptococcus pneumoniae
(
Spn
) and its infected host at disease relevant anatomical sites using mice as experimental models. We identify the shared and organ-specific transcriptomes of
Spn
, show that bacterial and host gene-expression profiles are highly distinct during asymptomatic colonization versus disease-causing infection, and demonstrate that
Spn
and host genes with high levels of expression contribute to pathogenesis or host defense, respectively, making them optimal targets for intervention.
Fluorine assembly nanocluster breaks the shackles of immunosuppression to turn the cold tumor hot
Authors: Li Zhaoting , Zhu Lianghan , Sun Honghao , Shen Yuexin , Hu Dandan , Wu Wenhao , Wang Yixin , Qian Chenggen , Sun Minjie
Published: December 2020

Significance

“Cold” tumors are good at camouflaging themselves, thus making it difficult for the immune system to recognize and to construct a great barrier for cancer immunotherapies. New methods that could awaken the immune system, enhance T cells and antigen-presenting cells (APCs) trafficking, and relieve immunosuppression to treat cold tumors are urgently in need. Here, we first report a chemically ingenious nanocluster FS@PMPt assembly by fluorine–fluorine interaction to regulate the immune process. The nanocluster not only increased the infiltration of immunopositive cells from the outside but also decreased the immunosuppressive cells from the inside to break the shackles of immunosuppression, which provides a promising paradigm for improving the anti–cold tumor immunotherapy.
Human embryonic stem cell-derived organoid retinoblastoma reveals a cancerous origin
Authors: Liu Hui , Zhang Yan , Zhang You-You , Li Yan-Ping , Hua Zi-Qi , Zhang Chang-Jun , Wu Kun-Chao , Yu Fulong , Zhang Yaru , Su Jianzhong , Jin Zi-Bing
Published: December 2020

Significance

As a genetic malignancy, retinoblastoma (Rb) is caused by
RB1
mutations; however, its developmental origin and drug agents for human Rb remain largely unexplored. Here we describe an innovative Rb organoid model derived from human embryonic stem cells with a biallelic mutagenesis of the
RB1
gene. We identify tumorigenic growth in the Rb organoids, as well as properties consistent with human primary Rb. We confirm that the Rb cell of origin stemmed from ARR3
+
maturing cone precursor cells and SYK inhibitors displaying a significant therapeutic response. Our elegant in-dish Rb organoid model can be used to efficiently and effectively dissect the origin of Rb and mechanisms of Rb tumorigenesis, as well as screen novel therapies.
A general fragment-based approach to identify and optimize bioactive ligands targeting RNA
Authors: Suresh Blessy M. , Li Weichao , Zhang Peiyuan , Wang Kye Won , Yildirim Ilyas , Parker Christopher G. , Disney Matthew D.
Published: December 2020

Significance

The development of selective bioactive compounds that target RNA structures is difficult. Here we report an approach to identify low molecular weight fragments that bind to a cancer-causing RNA. By determining where the fragments bind within an RNA target, they can be assembled to provide a high-affinity and potent inhibitor. This approach could be a general way to develop bioactive small molecules that target RNA, which previously was considered “undruggable.” It was applied to provide a precision lead medicine against an RNA that contributes to cancer metastasis.
An isolated water droplet in the aqueous solution of a supramolecular tetrahedral cage
Authors: Sebastiani Federico , Bender Trandon A. , Pezzotti Simone , Li Wan-Lu , Schwaab Gerhard , Bergman Robert G. , Raymond Kenneth N. , Toste F. Dean , Head-Gordon Teresa , Havenith Martina
Published: December 2020

Significance

Using a supramolecular assembly that catalyzes substrates in water, we show that the nanocage encapsulates a water cluster that is structurally and dynamically distinct from any known phase of water. It plays an important role in the driving force for guest encapsulation: The release of the highly unusual encapsulated water droplet creates a strong thermodynamic drive for the high-affinity binding of guests in aqueous solution for the supramolecular construct.
Direct quantification of in vivo mutagenesis and carcinogenesis using duplex sequencing
Authors: Valentine Charles C. , Young Robert R. , Fielden Mark R. , Kulkarni Rohan , Williams Lindsey N. , Li Tan , Minocherhomji Sheroy , Salk Jesse J.
Published: December 2020

Significance

Error-corrected next-generation sequencing (ecNGS) can be used to rapidly detect and quantify the in vivo mutagenic impact of environmental exposures or endogenous processes in any tissue, from any species, at any genomic location. The greater speed, higher scalability, richer data outputs, and cross-species and cross-locus applicability of ecNGS compared to existing methods make it a powerful new tool for mutational research, regulatory safety testing, and emerging clinical applications.
Stem water cryogenic extraction biases estimation in deuterium isotope composition of plant source water
Authors: Chen Yongle , Helliker Brent R. , Tang Xianhui , Li Fang , Zhou Youping , Song Xin
Published: December 2020

Significance

Stem xylem uptake and transport of plant source water is widely considered a critical component of the global water cycle. The deuterium signature of cryogenically extracted plant stem water (δ
2
H
stem_CVD
) provides a useful means for studying water fluxes, but recent studies have shown uncertainty as to whether δ
2
H
stem_CVD
is a faithful reflection of true source water isotopic signal (δ
2
H
source
). Here we confirm the common presence of significant deviations in δ
2
H
stem_CVD
from δ
2
H
source
in various plant species and demonstrate that this phenomenon is not caused by deuterium fractionation during root water uptake as traditionally thought, but rather is rooted in a cryogenic extraction-associated methodological artifact. Our findings may have wide-ranging implications for isotope-based ecohydrological and climate change studies.
A 2020 view of tension-based cortical morphogenesis
Authors: Van Essen David C.
Published: December 2020

Significance

Brain structures change shape dramatically during development. Elucidating the mechanisms of morphogenesis provides insights relevant to understanding brain function in health and disease. The tension-based morphogenesis (TBM) hypothesis posits that mechanical tension along axons, dendrites, and glial processes contributes to many aspects of central nervous system morphogenesis. Since TBM was proposed in 1997, extensive evidence supports a role for tension in diverse cellular phenomena, but tension’s role in cortical folding has been controversial. An extensively revised version of the TBM model for cerebral cortex addresses limitations of the original model, incorporates new features, and can be tested by many experimental approaches. For cerebellar cortex, a revised model accounts for many aspects of its development and adult architecture.
Quinine copolymer reporters promote efficient intracellular DNA delivery and illuminate a protein-induced unpackaging mechanism
Authors: Van Bruggen Craig , Punihaole David , Keith Allison R. , Schmitz Andrew J. , Tolar Jakub , Frontiera Renee R. , Reineke Theresa M.
Published: December 2020

Significance

Polymer-based vehicles that controllably deliver therapeutic nucleic acids to cells show great potential to develop safe and effective gene therapies. Realizing this potential, however, is limited by the lack of understanding of how polymers unpackage their cargo. We developed a quinine-containing polymer that shows exceptional gene delivery activity. A key aspect of this platform is that the quinine serves as a reporter for DNA binding using Raman spectroscopy. This allows us to track cargo release inside the cell using Raman chemical imaging. We find that proteins dominate the unpackaging of DNA encapsulated by these quinine polymers inside cells. This trackable delivery system should be broadly applicable to study nucleic acid delivery mechanisms and to be used for clinical therapy applications.
Large-scale mapping of live corals to guide reef conservation
Authors: Asner Gregory P. , Vaughn Nicholas R. , Heckler Joseph , Knapp David E. , Balzotti Christopher , Shafron Ethan , Martin Roberta E. , Neilson Brian J. , Gove Jamison M.
Published: December 2020

Significance

Coral reefs are changing at unprecedented rates, and the majority of reefs are undergoing widespread losses in live coral cover. Management and policy development efforts focused on conserving and restoring coral reefs are hampered by a lack of geographically consistent and actionable high-resolution information on the specific location and extent of live coral. Based on an operational airborne technique, we developed and applied a live coral mapping capability across the main Hawaiian islands to identify potential coral refugia as well as reefs for potential coral restoration. Our findings inform current management actions across the archipelago and demonstrate the tactical role that live coral mapping can play to support decision-making at large ecological scales.
Robust identification of investor beliefs
Authors: Chen Xiaohong , Hansen Lars Peter , Hansen Peter G.
Published: December 2020

Significance

Prices in asset markets reflect a combination of investor beliefs and their risk preferences. Researchers, as well as policymakers, look to asset market data as a barometer of public beliefs. Such data are informative because investors must be compensated for exposure to macroeconomic shocks, and thus beliefs about future macroeconomic performance are encoded in asset prices. This paper develops a method informed by data and models to recover information about investor beliefs. Our approach uses information embedded in forward-looking asset prices in conjunction with asset pricing models. We entertain families of potential belief distortions bounded by a statistical measure of divergence. Additionally, our method allows for the direct use of sparse survey evidence to make these bounds more informative.
Rewiring the specificity of extracytoplasmic function sigma factors
Authors: Todor Horia , Osadnik Hendrik , Campbell Elizabeth A. , Myers Kevin S. , Li Hao , Donohue Timothy J. , Gross Carol A.
Published: December 2020

Significance

Bacterial phenotypes require the concerted expression of multiple genes, usually coordinated by a transcriptional regulator. Although the functions of many genes in sequenced bacterial genomes can be inferred, the regulatory networks that coordinate their expression are only known in a few model systems. Using a bioinformatic and experimental approach, we solve the DNA-specificity code of extracytoplasmic function sigma factors (ECF σs), a major class of bacterial regulators. We develop and use a high-stringency pipeline to predict the genes regulated by 67% of ECF σs in >10,000 species, providing a comprehensive look at the role of a broadly distributed family of gene regulatory proteins. This conceptual and computational framework is potentially applicable to other bacterial regulators.
FXR mediates T cell-intrinsic responses to reduced feeding during infection
Authors: Campbell Clarissa , Marchildon Francois , Michaels Anthony J. , Takemoto Naofumi , van der Veeken Joris , Schizas Michail , Pritykin Yuri , Leslie Christina S. , Intlekofer Andrew M. , Cohen Paul , Rudensky Alexander Y.
Published: December 2020

Significance

Anorexia or decreased appetite is a common feature of infection. The effects of acute nutritional stress on effector T cells, which are required for pathogen-specific responses and protective immunological memory, are not fully understood. We show that reduced food intake during infection decreases the numbers of effector T cells in a manner dependent on the Farnesoid X Receptor (FXR). FXR was previously implicated in controlling hepatic responses to fasting. Our findings suggest that FXR functions in effector T cells to promote coherent physiological responses to decreased feeding, allowing organisms to scale their immune responses according to food availability.
Subcellular localization of the J-protein Sis1 regulates the heat shock response
Authors: Feder Zoë A. , Ali Asif , Singh Abhyudai , Krakowiak Joanna , Zheng Xu , Bindokas Vytas P. , Wolfgeher Donald , Kron Stephen J. , Pincus David
Published: December 2020

Cells exposed to heat shock induce a conserved gene expression program, the heat shock response (HSR), encoding protein homeostasis (proteostasis) factors. Heat shock also triggers proteostasis factors to form subcellular quality control bodies, but the relationship between these spatial structures and the HSR is unclear. Here we show that localization of the J-protein Sis1, a cofactor for the chaperone Hsp70, controls HSR activation in yeast. Under nonstress conditions, Sis1 is concentrated in the nucleoplasm, where it promotes Hsp70 binding to the transcription factor Hsf1, repressing the HSR. Upon heat shock, Sis1 forms an interconnected network with other proteostasis factors that spans the nucleolus and the surface of the endoplasmic reticulum. We propose that localization of Sis1 to this network directs Hsp70 activity away from Hsf1 in the nucleoplasm, leaving Hsf1 free to induce the HSR. In this manner, Sis1 couples HSR activation to the spatial organization of the proteostasis network.
Making Confident Decisions with Model Ensembles
Authors: Roussos Joe , Bradley Richard , Frigg Roman
Published: December 2020

Many policy decisions take input from collections of scientific models. Such decisions face significant and often poorly understood uncertainty. We rework the so-called confidence approach to tackle decision-making under severe uncertainty with multiple models, and we illustrate the approach with a case study: insurance pricing using hurricane models. The confidence approach has important consequences for this case and offers a powerful framework for a wide class of problems. We end by discussing different ways in which model ensembles can feed information into the approach, appropriate to different collections of models.
The Role of Historical Science in Methodological Actualism
Authors: Page Meghan D.
Published: December 2020

This article examines the role of historical science in clarifying the causal structure of complex natural processes. I reject the pervasive view that historical science does not uncover natural regularities. To show why, I consider an important methodological distinction in geology between uniformitarianism and actualism; methodological actualism, the preferred method of geologists, often relies on historical reconstructions to test the stability of currently observed processes. I provide several case studies that illustrate this, including one that highlights how historical narratives can improve predictive models.
Formation of high-photoresponsivity BaSi2 films on glass substrate by radio-frequency sputtering for solar cell applications
Authors: Koitabashi Ryota , Nemoto Taira , Yamashita Yudai , Mesuda Masami , Toko Kaoru , Suemasu Takashi
Published: December 2020

The formation of high-photoresponsivity semiconducting films composed of earth-abundant elements on a SiO2 substrate is of particular importance for large-scale deployment of solar cells. We investigated the deposition of high-photoresponsivity BaSi2 films by radio-frequency sputtering on indium-tin-oxide (ITO), Ti, or TiN electrodes formed on a SiO2 substrate. Raman spectroscopy and x-ray diffraction measurements revealed the formation of randomly oriented polycrystalline BaSi2 films only on TiN/SiO2 substrates at 570 °C–650 °C. In contrast, impurity phases such as Ba oxides and TiSi2 were included when ITO and Ti layers were used, respectively. The photoresponsivity of the BaSi2 films on TiN electrodes reached 1.1 A W−1 at a wavelength of 790 nm under a bias voltage of 0.5 V applied between the front ITO and bottom TiN electrodes. This value is equivalent to the highest photoresponsivity ever achieved for BaSi2 epitaxial films on Si(111) substrates by molecular beam epitaxy.
Length-scale independent skyrmion and meron Hall angles
Authors: Bera Sandip , Mandal Sudhansu S
Published: December 2020

Motivated by the recent observation (Zeissler et al 2020 Nature Commun.
11 428) of enigmatic radius-independent skyrmion Hall angle in chiral magnets, we derive skyrmion Hall angle based on the recent solution of skyrmions characterized by the sole length scale determined with the Dzyaloshinskii–Moriya interaction strength and applied magnetic field. We find that the skyrmion Hall angle is independent of input current density and the length-scale which determines the radius of a skyrmion. This is corroborated with the single length-scale dependent skyrmion profile which is the solution of the Euler equation of polar angle representing magnetization. Although the magnitude of Hall angle may change with the change of profile (shape) of the skyrmion, it remains unchanged for a particular profile. With the application of tunable current along mutually perpendicular directions, this property enables us to propose an experimental setup by which the transverse motion of a skyrmion can be restricted so that the skyrmion can only traverse longitudinally. We further find the length-scale and input-current density independent Hall angles for merons where their transverse motion will be opposite depending on whether the spin at their centers are up or down, in agreement with an experiment.
Role of anharmonic strength and number of allowed three-phonon processes in lattice thermal conductivity of SnTe based compounds
Authors: Keshri Sonu Prasad , Medhi Amal
Published: December 2020

The lattice heat transport properties of the thermoelectric (TE) material SnTe and the doped Sn7SbTe8 and Sn7BiTe8 are examined using Boltzmann transport theory supplemented with first-principle calculations. We illustrate the microscopic origin of the lattice thermal conductivity, κ
l of the materials by calculating the mode Grüneisen parameters, phase space volume for three-phonon processes, the anharmonic scattering rates (SR), and the phonon group velocities. SnTe is found to be a low κ
l material with a value of ∼3 W mK−1 at room temperature in agreement with experiments. The phonon scatterings in pristine SnTe mainly originates in the strong anharmonicity of the material, as evidenced by the large values of its mode Grüneisen parameters. Doping with Sb or Bi reduces the anharmonic strength. For Sb doped Sn7SbTe8, it results in a drop in the SR and hence a higher κ
l value. However in the Bi doped Sn7BiTe8, the number of allowed three-phonon processes gets greatly enhanced which compensates for the reduction in anharmonicity. This coupled with lower phonon group velocities lowers the κ
l value for the Bi doped system below that of pristine SnTe. In nanowire structures, κ
l values for the doped systems get drastically reduced yielding an ultra-low value of 0.84 W mK−1 at 705 K for the Bi doped material for a nanowire of 10 nm diameter.
Energy and electron drift time measurements in a pixel CCI TlBr detector with 1.3 MeV prompt-gammas
Authors: Ariño-Estrada Gerard , Kim Hadong , Du Junwei , Cirignano Leonard J , Shah Kanai S , Cherry Simon R
Published: December 2020

Assessing the position of the Bragg peak (BP) in hadron radiotherapy utilizing prompt-gamma imaging (PGI) presents many challenges in terms of detector physics. Gamma detectors with the capability of extracting the best energy, timing, and spatial information from each gamma interaction, as well as with high detection efficiency and count rate performance, are needed for this application. In this work we present the characterization of a pixel Čerenkov charge induction (CCI) thallium bromide (TlBr) detector in terms of energy and and electron drift time for its potential use in PGI. The CCI TlBr detector had dimensions of 4 × 4 × 5 mm3 and one of its electrodes was segmented in pixels with 1.7 mm pitch. A silicon photomultiplier (SiPM) was optically coupled to one of the faces of the TlBr slab to read out the Čerenkov light promptly emitted after the interaction of a gamma ray. The detector was operated stand-alone and the 1.275 prompt gammas from a 22Na radioactive source were used for the study. The electron drift time was obtained by combining the Čerenkov and charge induction signals and then used as a measure of the depth of interaction. The electron mobility in TlBr was estimated as ∼27 cm2 V−1 s−1. Energy resolutions between 3.4% and 4.0% at 1.275 MeV were obtained after depth-correction. These values improved to 3.0%–3.3% when events with drift times of 3–6 μs were selected. These results show the potential of pixel CCI TlBr detectors to resolve gamma interactions in the detector with mm-like accuracy in 3D and with excellent energy resolution. Previous studies with CCI TlBr devices have shown a timing resolution of <400 ps full width at half maximum when detecting 511 keV gamma rays, therefore, the timing accuracy is expected to improve with the increased energy of the gamma rays in PGI. While other important detector characteristics such as count rate capability remain to be studied, results from this work combined with other preliminary data show pixel CCI detectors can simultaneously provide excellent energy, timing, and spatial resolution performance and are a very promising option for PGI in hadron therapy.
Iterative time-reversal for multi-frequency hyperthermia
Authors: Zanoli Massimiliano , Trefná Hana Dobšíček
Published: December 2020

Time-reversal (TR) is a known wideband array beam-forming technique that has been suggested as a treatment planning alternative in deep microwave hyperthermia for cancer treatment. While the aim in classic TR is to focus the energy at a specific point within the target, no assumptions are made on secondary lobes that might arise in the healthy tissues. These secondary lobes, together with tissue heterogeneity, may result in hot-spots (HSs), which are known to limit the efficiency of the thermal dose delivery to the tumor. This paper proposes a novel wideband TR focusing method that iteratively shifts the focus away from HSs and towards cold-spots from an initial TR solution, a procedure that improves tumor coverage and reduces HSs. We verify this method on two different applicator topologies and several target volume configurations. The algorithm is deterministic and runs within seconds, enabling its use for real-time applications. At the same time, it yields results comparable to those obtained with global stochastic optimizers such as Particle Swarm.
Magnetic confinement and instability in partially magnetized plasma
Authors: Kim June Young , Jang Jae Young , Choi Jaeyoung , Wang Jong-in , Jeong Won Ik , Elgarhy M A I , Go Geunwoo , Chung Kyoung-Jae , Hwang Y S
Published: December 2020

Discharge with an external magnetic field is promising for various applications of low-temperature plasmas from electric propulsion to semiconductor processes owing to high plasma density. It is essential to understand plasma transport across the magnetic field because plasma confinement under the field is based on strong magnetization of light electrons, maintaining quasi-neutrality through the inertial response of unmagnetized ions. In such a partially magnetized plasma, different degrees of magnetization between electrons and ions can create instability and make the confinement and transport mechanisms more complex. Theoretical studies have suggested a link between the instability of various frequency ranges and plasma confinement, whereas experimental work has not been done so far. Here, we experimentally study the magnetic confinement properties of a partially magnetized plasma considering instability. The plasma properties show non-uniform characteristics as the magnetic field increases, indicating enhanced magnetic confinement. However, the strengthened electric field at the edge of the plasma column gives rise to the Simon–Hoh instability, limiting the plasma confinement. The variation of the edge-to-center plasma density ratio (h-factor) with the magnetic field clearly reveals the transition of the transport regime through triggering of the instability. Eventually, the h-factor reaches an asymptotic value, indicating saturation of magnetic confinement.
Construction of propagators for divisible dynamical maps
Authors: Chakraborty Ujan , Chruściński Dariusz
Published: December 2020

Divisible dynamical maps play an important role in characterizing Markovianity on the level of quantum evolution. Divisible maps provide an important generalization of Markovian semigroups. Usually one analyzes either completely positive or just positive divisibility meaning that the corresponding propagators are defined in terms of completely positive or positive maps, respectively. For maps which are invertible at any moment of time the very existence of propagator is already guaranteed and hence the only issue is (complete) positivity and trace-preservation. However, for maps which are not invertible the problem is much more involved since even the existence of a propagator is not guaranteed. In this paper we propose a simple method to construct propagators of dynamical maps using the concept of generalized inverse. We analyze both time-continuous and time-discrete maps. Since the generalized inverse is not uniquely defined the same applies for the corresponding propagator. In simple examples of qubit evolution we analyze it turns out that the additional requirement of complete positivity possibly makes the propagator unique.
Moses, Noah and Joseph effects in Lévy walks
Authors: Aghion Erez , Meyer Philipp G , Adlakha Vidushi , Kantz Holger , Bassler Kevin E
Published: December 2020

We study a method for detecting the origins of anomalous diffusion, when it is observed in an ensemble of times-series, generated experimentally or numerically, without having knowledge about the exact underlying dynamics. The reasons for anomalous diffusive scaling of the mean-squared displacement are decomposed into three root causes: increment correlations are expressed by the ‘Joseph effect’ (Mandelbrot and Wallis 1968 Water Resour. Res.
4 909), fat-tails of the increment probability density lead to a ‘Noah effect’ (Mandelbrot and Wallis 1968 Water Resour. Res.
4 909), and non-stationarity, to the ‘Moses effect’ (Chen et al 2017 Phys. Rev. E
95 042141). After appropriate rescaling, based on the quantification of these effects, the increment distribution converges at increasing times to a time-invariant asymptotic shape. For different processes, this asymptotic limit can be an equilibrium state, an infinite-invariant, or an infinite-covariant density. We use numerical methods of time-series analysis to quantify the three effects in a model of a non-linearly coupled Lévy walk, compare our results to theoretical predictions, and discuss the generality of the method.
Carboplatin delivery system based on poly(ethylene glycol) methyl ether–cholesterol modified soy lecithin liposomes
Authors: Trang Le Ngoc Thuy , Nguyen Cuu Khoa , Nguyen Dai Hai
Published: December 2020

Liposomes are well studied and proved to have enormous potential for carboplatin delivery in cancer treatment. However, to achieve an ideal liposome system with less leakage and controlled release for an effective delivery of carboplatin (CPT) to tumor sites is still in progress. In this study, poly(ethylene glycol) methyl ether-cholesterol (mPEG-Chol) was prepared and used as a component, together with soy lecithin and cholesterol, to synthesize liposomes through thin film hydration method. The particle size distribution of obtained system of mPEG-Chol modified soy lecithin liposomes (mPEG-Chol-SLP) was then reduced by sonication, followed by extrusion. The properties of these nanoparticles including particle size, polydispersity index, zeta potential, and morphology were assessed by dynamic light scattering (DLS), zeta potential measurement, and transmission electron microscopy (TEM). Using dialysis method as the in vitro tests, the drug loading and releasing efficiency were calculated with pre-determined formulas. The cytotoxicity in the human breast cancer cell line (MCF-7) was evaluated through the cell proliferation assay WST-1. The results showed that CPT-loaded mPEG-Chol-SLP was spherical in shape with the average particle diameter and polydispersity index of 173.10 nm and 0.174, respectively. Moreover, the system was negatively charged, relatively colloidal stable, 70.49% for drug loading efficiency, and slowly released up to 48 h. In addition, the cytotoxicity data showed that mPEG-Chol-SLP was biocompatible nanocarrier and successfully reduced the toxicity of CPT. These results demonstrated that the obtained CPT-loaded mPEG-Chol-SLP reached one step closer to an ideal nanocarrier for CPT delivery.
Direct observation of layer-stacking and oriented wrinkles in multilayer hexagonal boron nitride
Authors: Chen Lingxiu , Elibol Kenan , Cai Haifang , Jiang Chengxin , Shi Wenhao , Chen Chen , Wang Hui Shan , Wang Xiujun , Mu Xiaojing , Li Chen , Watanabe Kenji , Taniguchi Takashi , Guo Yufeng , Meyer Jannik C , Wang Haomin
Published: December 2020

Hexagonal boron nitride (h-BN) has long been recognized as an ideal substrate for electronic devices due to its dangling-bond-free surface, insulating nature and thermal/chemical stability. These properties of the h-BN multilayer are mainly determined by its lattice structure. Therefore, to analyse the lattice structure and orientation of h-BN crystals becomes important. Here, the stacking order and wrinkles of h-BN are investigated by transmission electron microscopy. It is experimentally confirmed that the layers in the h-BN flakes are arranged in the AA′ stacking. The wrinkles in a form of threefold network throughout the h-BN crystal are oriented along the armchair direction, and their formation mechanism was further explored by molecular dynamics simulations. Our findings provide a deep insight about the microstructure of h-BN and shed light on the structural design/electronic modulations of two-dimensional crystals.
Effects of pre-creep on dislocation and tensile property of Cr-Ni steel
Authors: Pei Hai-Xiang , Yang Xiao-Min , Fang Xu-Dong , Zhao Yu-Hong , Huo Hua
Published: December 2020

Pre-creep experiments were performed on chromium-nickel (Cr-Ni) stainless steel in the early stage of creep. The temperature was held for 500–2000 h under high-temperature load conditions (873 K and 150 MPa), and various analysis methods, including optical microscopy, electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), and X-ray diffraction, were used to determine the pattern of dislocation evolution under different temperature-holding times. The results showed that the slip bands intersected at the initial stage of pre-creep, and a quadrilateral network structure was formed by the dislocation pinning. As the temperature-holding time increased, the dislocation network began to climb to form dislocation walls, dislocation cells, and other substructures. At 2000 h, the grain boundaries widened considerably; creep holes were found at the grain boundaries; and dislocation pairs with oscillating contrast occurred, which indicates nitrogen diffusion. The yield and tensile strengths of the Cr-Ni steel samples subjected to pre-creep at holding times of above 1000 h decreased after they were subjected to room-temperature tensile tests.
Whispering gallery and surface mode of electrons in lateral and corrugated quantum dots
Authors: Ramezanpour Shahab
Published: December 2020

Quantum dots (QDs) are fundamental elements in the applications related to light–matter interaction, such as solar cells, lasers and sensors. Moreover, some modes of electrons including whispering galley modes (WGMs) and surface modes can be incorporated in many electronic systems, in high Q-resonators, and quantized reflection/transmission. Therefore, controlling and manipulating their energy spectra is vital. Here, we investigate energy spectra as well as WGM and surface mode of electrons in lateral and corrugated QDs. Although, lateral QDs are usually modelled by a 2D harmonic oscillator (with zero thickness), we show that even very small thickness of dots can change their energy spectra, also they can contain surface mode of electrons. Moreover, we investigate WGM in deformed QDs, and the dots which contain corners in their outermost region, and show that some degenerated points would be created. Meanwhile, in the corrugated QDs, the wavefunction would be distributed in the specific teeth based on its energy level.
Recent progress and challenges based on two-dimensional material photodetectors
Authors: Zhang Kaixuan , Zhang Libo , Han Li , Wang Lin , Chen Zhiqingzi , Xing Huaizhong , Chen Xiaoshuang
Published: December 2020

Two-dimensional (2D) materials have excellent electronic and optoelectronic properties, such as ultrafast charge transport and tunable photon absorption. These 2D materials include topological semimetal graphene, semiconductor material black phosphorus, transition-metal dichalcogenides, etc. Studying the ultra-high optical response speed and sensitivity, broadband spectrum and other excellent performance photodetectors are the goals of continuous pursuit and challenge. 2D material photodetectors have become a research hotspot due to the special propert-ies of 2D materials including flexible tuning, no dangling bonds, high mobility, and many more. Herein, the electronic and optoelectronic properties of 2D materials and the quality factors of the photodetector are introduced. Then, the 2D material-based photodetectors with a detection wavelength from visible light to the terahertz band are summarized systematically. Finally, the prospects and challenges of 2D material-based photodetectors are discussed briefly.
The threshold for the square of a Hamilton cycle
Authors: Kahn Jeff , Narayanan Bhargav , Park Jinyoung
Published: December 2020

Resolving a conjecture of Kühn and Osthus from 2012, we show that

p
=
1

/

n

p= 1/\sqrt {n}

is the threshold for the random graph

G

n
,
p

G_{n,p}

to contain the square of a Hamilton cycle.
Transforming data into insight: Establishment of a pharmacy analytics and outcomes team
Authors: Vest Mary-Haston , Colmenares Evan W , Pappas Ashley L
Published: December 2020

Purpose

The importance of a data management strategy is increasingly necessary for demonstrating value and driving performance within pharmacy departments. Data analytics capabilities often do not match the pace of data accumulation. At our organization, the establishment of an embedded pharmacy analytics and outcomes (PAO) team has been instrumental to pharmacy services in generating and demonstrating value and proactively supporting a business intelligence strategy grounded in a data-driven culture.

The PAO team was established to support the operational and strategic needs of clinical, financial, and operational pharmacy services. The team is charged with implementing the vision of extending medication-use influence and data insight to drive value-based patient care outcomes while decreasing waste, optimizing therapeutic decisions, and achieving medication management standardization across the continuum of healthcare. The PAO team is composed of 3 pharmacist full-time equivalents (FTEs), 5 business analyst FTEs, 1 biostatistician FTE, 0.2 pharmacy intern FTE, and 1 pharmacy manager FTE. Pharmacy services leaders believe it is necessary to have a mix of both clinical and analytical skill sets, given the clinical nature of the data managed by team and complexities of the medication-use process.

Conclusion

Pharmacy reporting and analytics should require the same depth of scrutiny and overview as any other step in the medication-use process where pharmacists are held accountable. For our organization, it was critical to establish pharmacist-level oversight into every portion of the analytics process where medication data are involved. This structure has led to measurable improvements in patient outcomes, operational efficiency, and financial performance.
A non-linear regression method for estimation of gene–environment heritability
Authors: Kerin Matthew , Marchini Jonathan
Published: December 2020

Motivation

Gene–environment (GxE) interactions are one of the least studied aspects of the genetic architecture of human traits and diseases. The environment of an individual is inherently high dimensional, evolves through time and can be expensive and time consuming to measure. The UK Biobank study, with all 500 000 participants having undergone an extensive baseline questionnaire, represents a unique opportunity to assess GxE heritability for many traits and diseases in a well powered setting.

Results

We have developed a randomized Haseman–Elston non-linear regression method applicable when many environmental variables have been measured on each individual. The method (GPLEMMA) simultaneously estimates a linear environmental score (ES) and its GxE heritability. We compare the method via simulation to a whole-genome regression approach (LEMMA) for estimating GxE heritability. We show that GPLEMMA is more computationally efficient than LEMMA on large datasets, and produces results highly correlated with those from LEMMA when applied to simulated data and real data from the UK Biobank.

Availability and implementation

Software implementing the GPLEMMA method is available from https://jmarchini.org/gplemma/.

Supplementary information

Supplementary data are available at Bioinformatics online.