bluuebunny/crossref_metadata_2025 huggingface dataset:
Reliability of Temporal Vascular Anastomosis and Techniques for Better Outcomes
Authors: Tanaka Kentaro , Suesada Nobuko , Homma Tsutomu , Mori Hiroki , Okazaki Mutsumi
Published: June 2021

Background Although there are several potential recipient vessels in the neck, those in the temporal region are limited. In skull base reconstruction, there are difficulties associated with the anastomosing recipient vessels in the neck region since long nutrient vessels are needed in the flap. We evaluated the reliability of temporal vascular anastomosis by comparing surgical outcomes between reconstructive methods and examined which surgical procedures may achieve better results.

Methods We examined the medical records of free tissue transfer cases between April 2007 and March 2018. Seventy-three surgeries were performed in the temporal region, including skull base reconstruction in 48, head and neck reconstruction (without skull base) in 16, and secondary surgery for head deformities in nine cases. In total, 445 neck surgeries were performed. Postoperative complications were retrospectively analyzed.

Results The postoperative complication rates were 8.2 and 2.7% for all temporal and neck surgeries, respectively. There were no arterial complications in the temporal region and all of the six postoperative anastomotic complications were due to venous thrombosis. In contrast, there were 12 cases of vascular anastomotic complications, with six cases each of arterial and venous thrombosis in the neck. In the temporal region, the complication rate was 2.1% for skull base reconstruction, 11% for secondary revision, and 25% in head and neck reconstruction. The corresponding values for middle temporal vein (MTV) usage rates were 54, 22, and 25%. In skull base reconstruction, a coronal incision was made in all cases. A more frequent use of the MTV was associated with a reduced complication rate.

Conclusion The low complication rate in the temporal region was attributed to the wide surgical field and low tension of anastomotic vessels. Multiple venous anastomoses, including those of the MTV, are recommended to prevent complications.
Effect of compression in molecular spin-crossover chains
Authors: Gudyma A. , Gudyma Iu.
Published: June 2021

The thermodynamic properties of a one-dimensional spin-crossover molecular chain under constant external pressure are investigated. The effective compressible degenerate Ising model is used as a theoretical basis. Analytical results for the crossover from low to high spin are obtained using the transfer matrix formalism. Exact expressions are obtained for the fraction of molecules in the high-spin state, the correlation function, and the heat capacity. The analysis of the range of parameters in which the spin-crossover occurs is carried out, and it is shown how the pressure changes the position of the crossover.
Two-dimensional Berezinskii–Kosterlitz–Thouless topological phase transition in three-dimensional Bi2Sr2Ca2Cu3O10+x:(La,Sr)MnO3 nanocomposites
Authors: D’yachenko A. I. , Krivoruchko V. N. , Tarenkov V. Yu.
Published: June 2021

Electrical transport properties of random binary networks composed of high-Tc superconductor Bi2Sr2Ca2Cu3O10+x (Bi2223) microparticles and half-metal ferromagnet La2/3Sr1/3MnO3 (LSMO) nanoparticles have been investigated. The experimental current-voltage characteristics of bulk samples of nanocomposites with a volumetric content of 4:1 components are well described by the Berezinsky–Kosterlitz–Thouless (BKT) model for two-dimensional (2D) superconductors undergoing a superconducting transition. The observed 2D-like behavior of the three-dimensional transport properties of the nanocomposite is most likely associated with two different physical spatial scales involved in the formation of the properties of the nanocomposite: a significant difference between the geometric dimensions of the constituent components and the appearance of a triplet superconducting state induced by the proximity effect in semi-metallic manganite LSMO contacting Bi2223. Below the Bi2223 superconducting transition temperature, bulk resistive losses in the nanostructures are determined by the current flowing through ferromagnetic LSMO nanoparticles that cover Bi2223 microgranules. As temperature decreases, proximity-induced superconducting transition in the effectively 2D surface of LSMO nanoparticles covering Bi2223 microgranules reveals itself as the topological BKT-like superconducting transition in the bulk sample.
Interatomic interaction within a 4He−4He dimer with mobile nuclei
Authors: Chishko K. A.
Published: June 2021

Schrodinger equation for system of two mobile spinless nucleus with Z0 = 2 and four electrons (4He2-dimer) has been solved in the framework of exact diagonalization approach. The spectrum has been obtained with basis of 1134 functions built as direct product of one-particle hydrogen-like functions which are solutions of the exactly solved Sturm-Liouville problem. The asymptotic (Van der Waals) behavior of interaction between two 4He atoms in the limit R0→∞ has been analyzed and discussed. The contribution to the interaction energy from four electronic spins on the 4He–4He bond has been calculated the exact diagonalization procedure.
Pressure-tuned colossal magnetoresistance effect in n-type CdCr2Se4
Authors: Zhang Bowen , Gu Chuanchuan , An Chao , Chen Xuliang , Zhou Yonghui , Zhou Ying , Yang Zhaorong
Published: June 2021

The p-type CdCr2Se4 exhibits semiconducting conductivity while n-type CdCr2Se4 displays a semiconductor–metal transition and a concomitant colossal magnetoresistance near the Curie temperature. Here, we investigate the pressure effect on the conductivity for both types of compounds. We show that the resistance of p-type sample decreases continuously upon compression, while the semiconducting behavior dominates up to 27.9 GPa. For the n-type sample, the semiconductor-metal transition is suppressed gradually with the increase in pressure; meanwhile, the magnetoresistance becomes less and less pronounced and is negligible at 9.2 GPa. Combined with in situ high-pressure magnetization, x-ray diffraction, and Raman spectra investigations, a ferromagnetic ground state is deduced in the pressurized n-type CdCr2Se4 before the structural transition, which is in stark contrast to the pressure effect on n-type HgCr2Se4.
Perpendicular magnetic anisotropy in ultra-thin Cu2Sb-type (Mn–Cr)AlGe films fabricated onto thermally oxidized silicon substrates
Authors: Kubota Takahide , Ito Keita , Umetsu Rie Y. , Takanashi Koki
Published: June 2021

Perpendicularly magnetized films exhibiting small saturation magnetizations (Ms) are essential for spin-transfer-torque magnetoresistive random access memories (MRAMs). In this study, the intermetallic compound (Mn–Cr)AlGe with a Cu2Sb crystal structure was investigated as a material exhibiting low Ms (∼300 kA/m) and high-perpendicular magnetic anisotropy energy (Ku). The layer thickness dependence of Ku and effects of Mg-insertion layers at the top and bottom (Mn–Cr)AlGe|MgO interfaces were studied for film samples fabricated onto thermally oxidized silicon substrates to realize high Ku values in the thickness range of a few nanometers. The values of Ku were approximately 7×105 and 2×105 J/m3 at room temperature for 5 and 3 nm-thick (Mn–Cr)AlGe films, respectively, with an optimum annealing temperature of 400 °C and Mg-insertion thicknesses of 1.4 and 3.0 nm for the top and bottom interfaces, respectively. The Mg insertions were relatively thick compared with results of similar studies of the insertion effect on magnetic tunnel junctions. Cross-sectional transmission electron microscope images revealed that the Mg-insertion layers acted as barriers to the interdiffusion of Al atoms as well as oxidization from the MgO layers. The Ku at a few-nanometer thicknesses was comparable to or higher than those reported for perpendicularly magnetized CoFeB films, which are conventionally used in MRAMs, whereas the Ms value was one third or smaller than those of the CoFeB films. The developed (Mn–Cr)AlGe films are promising materials because of their magnetic properties and their compatibility to the silicon process in film fabrication.
Transition pathways for a class of high dimensional stochastic dynamical systems with Lévy noise
Authors: Hu Jianyu , Chen Jianyu
Published: June 2021

This work is devoted to deriving the Onsager–Machlup action functional for a class of stochastic differential equations with (non-Gaussian) Lévy process as well as Brownian motion in high dimensions. This is achieved by applying the Girsanov transformation for probability measures and then by a path representation. The Poincaré lemma is essential to handle such a path representation problem in high dimensions. We provide a sufficient condition on the vector field such that this path representation holds in high dimensions. Moreover, this Onsager–Machlup action functional may be considered as the integral of a Lagrangian. Finally, by a variational principle, we investigate the most probable transition pathways analytically and numerically.
Exchange bias and spin–orbit torque in the Fe3GeTe2-based heterostructures prepared by vacuum exfoliation approach
Authors: Zhang Yu , Xu Hongjun , Yi Changjiang , Wang Xiao , Huang Yuan , Tang Jian , Jiang Jialiang , He Congli , Zhao Mingkun , Ma Tianyi , Dong Jing , Guo Chenyang , Feng Jiafeng , Wan Caihua , Wei Hongxiang , Du Haifeng , Shi Youguo , Yu Guoqiang , Zhang Guangyu , Han Xiufeng
Published: June 2021

Magnetic two-dimensional (2D) van der Waals (vdWs) materials are receiving increased attention due to their exceptional properties and potential applications in spintronic devices. Because exchange bias and spin–orbit torque (SOT)-driven magnetization switching are basic ingredients for spintronic devices, it is of pivotal importance to demonstrate these effects in the 2D vdWs material-based magnetic heterostructures. In this work, we employ a vacuum exfoliation approach to fabricate Fe3GeTe2 (FGT)/Ir22Mn78 (IrMn) and FGT/Pt bilayers, which have high-quality interfaces. An out-of-plane exchange bias of up to 895 Oe is obtained in the former bilayer, which is larger than that of the previously studied bilayers. In the latter bilayer, the SOT switching of the perpendicularly magnetized FGT is realized, which exhibits higher SOT-driven switching performance compared to the previously studied FGT/Pt bilayer devices with interfacial oxidation. The minimum of SOT efficiency is further determined to be 0.18 ± 0.04, comparable to the previously reported values for the Pt/Co and Pt/CoFeB bilayers. This work highlights the importance of the high-quality interface for the exchange bias and SOT effect and may pave the way for implementing 2D vdWs in spintronic devices.
Strain-mediated tunability of spin-wave spectra in the adjacent magnonic crystal stripes with piezoelectric layer
Authors: Grachev A. A. , Matveev O. V. , Mruczkiewicz M. , Morozova M. A. , Beginin E. N. , Sheshukova S. E. , Sadovnikov A. V.
Published: June 2021

We demonstrate that properties of spin-wave propagation in the adjacent magnonic crystal stripes with one of them in contact with a piezoelectric layer can be controlled by an external electric field. We perform microwave spectroscopy and employ a theoretical approach based on the analysis of the set of coupled wave equations. By considering incident and reflected waves in the first Brillouin zone, we calculate the reflection coefficients of the magnonic structure. Two narrow magnon bands are observed in the experiment, and their behavior with the variation of the electric field applied to the piezoelectric layer was shown. The finite-element calculations of the self-consistent eigenvalue problem elucidate how the influence of the piezoelectric layer can be modeled as a localized strain-induced internal magnetic field and its variation affects the spin-wave dispersion. Both the frequency shift and closing of a magnon band are detected in our measurements and confirmed by the simulations and the analytical approach. Therefore, we demonstrate the electric field control of the magnonic bands. Our results reveal the mechanism of the spin-wave spectra control in the coupled magnonic crystals. The results pave the way for the implementation of frequency selective magnonic devices based on a straintronic approach.
Spin–charge conversion in transition metal oxides
Authors: Chen Hetian , Yi Di
Published: June 2021

The interaction between spin and charge degrees of freedom offers a powerful tool to manipulate magnetization in memories by the current induced spin–orbit torque. This novel phenomenon, conventionally existing in semiconductors and metallic systems, has recently been observed in transition metal oxides, exhibiting a surprising large spin-Hall angle. In this Perspective, we will review recent research progress in the spin–charge conversion in transition metal oxides, the remaining challenges, and new opportunities. We will first briefly summarize recent progress in the spin–charge conversion in representative transition metal oxides, including SrIrO3, SrRuO3, and IrO2, along with other materials predicted by calculations. Next, we will survey the possible candidate materials in the family of transition metal oxides. Recent advances in the growth of SrIrO3 films will be reviewed along with the implications on the study of the spin-Hall effect. We will also discuss other promising candidates that could serve as the spin source, including films of pyrochlore and delafossite oxides as well as oxide heterostructures.
Coalescence and splashing threshold for head-on collisions of liquid metal nanodroplets
Authors: Barclay Paul L. , Zhang Duan Z.
Published: June 2021

Head-on collisions of liquid metal nanodroplets in a vacuum are investigated through molecular dynamics simulations in order to determine the transition threshold between the coalescing and splashing regimes for six different materials (aluminum, calcium, cerium, gold, platinum, and tin). Droplets of various sizes and initial speeds are simulated, and it is found that the Reynolds and Ohnesorge numbers are able to predict the transition between the coalescing and splashing regimes. An energy balance for coalescing droplets shows that the initial energy is mainly converted to thermal energy increasing the temperature of the combined droplets by several hundred to several thousand kelvin depending on the material, and this result is confirmed in the simulations. When splashing occurs, the number of smaller droplets formed and the spreading rate are found to be dependent on the initial size and initial speed of the original droplets.
Semiconductor-to-metal transition in atomic layer deposition (ALD) of VO2 films using VCl4 and water
Authors: Ganesan Jeya Prakash , Dev Durjoy , Krishnaprasad Adithi , Feit Corbin , Moser Daniel , Kanjolia Ravindra K. , Roy Tania , Banerjee Parag
Published: June 2021

The semiconductor-to-metal transition of vanadium dioxide (VO2) films is studied using temperature-dependent Raman, optical, and electrical measurements. The VO2 films are deposited via an atomic layer deposition (ALD) process using alternate pulses of vanadium tetrachloride and H2O at 350 °C. A growth rate of 0.021 nm/cycle and a thickness of 33 nm of VO2 are obtained for all films studied. The phase of the film is determined using x-ray diffraction. The as-deposited films are amorphous and are transformed to the monoclinic phase with a post-deposition, forming gas anneal at temperatures ≥ 500 °C for 60 min. The purity of the films is determined using x-ray photoelectron spectroscopy and no evidence of residual chlorine is detected. The temperature-dependent Raman Ag mode of the monoclinic VO2 phase is observed to monotonically decrease from 25 °C to 78 °C; where no evidence of the Ag peak is observed in the film beyond 68 °C. The refractive index and extinction coefficient extracted from temperature-dependent ellipsometry confirm that, beyond 68 °C, free carriers are generated in the film. Electrical measurements performed on a fabricated p++Si/VO2/Ti/Au device show a semiconductor-to-metal transition behavior with a high resistance of 14701 ± 2284 Ω at 62 °C and a low resistance of 1064.1 ± 143 Ω at 67 °C. This work demonstrates that a halide-based ALD process provides a clean and robust approach to synthesizing high-quality VO2 films.
The relativistic effects on the methane activation by gold(I) cations
Authors: Santiago Régis T. , Vichietti Rafael M. , Machado Francisco B. C. , Haiduke Roberto L. A.
Published: June 2021

The reactivity of gold has been investigated for a long time. Here, we performed an in-depth analysis of relativistic effects over the chemical kinetic properties of elementary reactions associated with methane activation by gold(I) cations, CH4 + Au+ ↔ AuCH2+ + H2. The global reaction is modeled as a two-step process, CH4 + Au+ ↔ HAuCH3+ ↔ AuCH2+ + H2. Moreover, the barrierless dissociation of the initial adduct between reactants, AuCH4+, is discussed as well. Higher-order relativistic treatments are used to provide corrections beyond the commonly considered scalar effects of relativistic effective core potentials (RECPs). Although the scalar relativistic contributions predominate, lowering the forward barrier heights by 48.4 and 36.1 kcal mol−1, the spin–orbit coupling effect can still provide additional reductions of these forward barrier heights by as much as 9% (1.0 and 2.2 kcal mol−1). The global reaction proceeds rapidly at low temperatures to the intermediate attained after the first hydrogen transfer, HAuCH3+. The relativistic corrections beyond the ones from RECPs are still able to double the rate constant of the CH4 + Au+ → HAuCH3+ process at 300 K, while the reverse reaction becomes five times slower. The formation of global products from this intermediate only becomes significant at much higher temperatures (∼1500 K upward). The scalar relativistic contributions decrease the dissociation energy of the initial adduct, AuCH4+, into the global products by 105.8 kcal mol−1, while the spin–orbit effect provides an extra lowering of 1.8 kcal mol−1.
Temperature biosensor based on triangular lattice phononic crystals
Authors: Zaremanesh Mansour , Carpentier Laurent , Gharibi Hamed , Bahrami Ali , Mehaney Ahmed , Gueddida Abdellatif , Lucklum Ralf , Djafari-Rouhani Bahram , Pennec Yan
Published: June 2021

A two-dimensional triangular lattice solid/fluid phononic crystal (PnC) is proposed as a sensitive biosensor to detect the temperature of the Methyl Nonafluorobutyl Ether (MNE) in the range of 10–40 °C. Temperature changes in MNE represent an important issue for its various applications. Indeed, the MNE is widely used in cosmetic and beauty products for its non-toxic, non-flammable, and colorless chemical properties. For this purpose, a sensitive biosensor for temperature and physical properties of MNE appears necessary. The PnC biosensor consists of a triangular lattice of tungsten cylinders embedded in an epoxy background inside of which a line of hollow cylinders filled with MNE is introduced as a waveguide for guiding resonant modes with low group velocity. We show that the PnC biosensor provides sharp guided modes in the bandgap with high quality factors and frequencies depending on the MNE temperature with high sensitivity. The introduction of damping inside the liquid shows that the shear viscosity, compared to longitudinal, affects drastically the amplitude of the resonant peaks. However, the length of the waveguide can be adapted so as to recover the resonant peak in the presence of viscosities.
Modulations of interfacial magnetic properties using structurally inverted magnetic tri-layer systems: Toward skyrmion formation
Authors: Jung Jinyong , Cho Jaehun , Choi Hyeok-Cheol , Lee Kwanghyun , You Chun-Yeol , Choe Sug-Bong , Kim June-Seo
Published: June 2021

Various magnetic properties such as the interfacial Dzyaloshinskii–Moriya interaction (DMI) and the perpendicular magnetic anisotropy (PMA) in structurally inverted Pd/Co/Pt and Pt/Co/Pd tri-layer stacks are systematically investigated by performing an inelastic light scattering method. Two examined individual multilayer structures are identical, but the stacking order is inverted for each other. Here, we demonstrate that the interfacial DMI energy densities and the saturation magnetization values for both systems are almost similar. However, the surface magnetic anisotropy energy densities of Pd/Co/Pt systems are dramatically decreased up to 34% compared with Pt/Co/Pd system, while the interfacial DMI is kept. Since a large interfacial DMI and a small PMA (or domain wall energy) are required to form magnetic skyrmion phases, the Pd/Co/Pt system can be one of the promising candidates. According to the thickness dependent measurements, we show a possibility of the existence of skyrmion phases in the Pd/Co/Pt system within a certain range of Co layer thickness at room temperature without external magnetic fields.
Engineering the collapse of lifetime distribution of nitrogen-vacancy centers in nanodiamonds
Authors: Li H. , Ou J. Y. , Gholipour B. , So J. K. , Piccinotti D. , Fedotov V. A. , Papasimakis N.
Published: June 2021

We demonstrate experimentally that the distribution of the decay rates of nitrogen-vacancy centers in diamond becomes narrower by over five times for nanodiamonds embedded in thin chalcogenide films.
Measurement of third-order elastic constants using thermal modulation of ultrasonic waves
Authors: Zhong Bibo , Zhu Jinying
Published: June 2021

Third-order elastic constants (TOEC) play an important role in nonlinear material characterization, but measurements of TOEC are laborious with large error margins. This Letter presents the equations of wave velocity changes caused by homogeneous temperature variation and uniaxial stress in isotropic media and the expression of TOEC in terms of thermally induced velocity change and thermal strain. TOEC of an aluminum sample were experimentally determined by measuring ultrasonic wave velocity changes in the uniaxial loading test and the thermal modulation test. Experimental results showed good agreement between the two test methods. Owing to the simple test setup and high measurement sensitivity, the thermal modulation test is a potential experimental method to determine TOEC and absolute acoustic nonlinearity parameters.
Landing with confidence and accuracy in a big bore subsea gas producer – an integrated approach for setting a critical casing point in the Jansz-Io field development
Authors: Thomas Leigh , Waugh Matthew , Thornberry Matthew , Wang Hanming , Wang Haifeng , Hafezi Farshid , Dolan James , Ali Anis
Published: June 2021

As part of the Gorgon Stage 2 project, a total of four production wells were installed at a new manifold within the Jansz-Io gas field. A key well construction challenge was the placement of the 12 ¼″ section total depth (TD). Due to the presence of reservoir depletion, the mud weight required to drill the sandstone would be insufficient to prevent wellbore collapse in the Barrow Shale immediately above the reservoir. Hence, the casing design called to isolate the entire Barrow Shale interval by placing the 9 ⅝″ production liner shoe immediately inside the reservoir. To avoid damaging the high-quality sandstone in the upper reservoir, it was desired to limit the reservoir penetration to less than 1m true vertical depth (TVD) at 80° inclination. Chevron recognised several challenges in landing the wells, which included: seismic uncertainty of the reservoir top, poor resistivity contrast and the lack of significant markers in the overburden. Conventional methods such as near-bit gamma ray carried high risk because the sensor offset to bit is close to the penetration limit. Therefore, a new approach of integrating a deep directional resistivity (DDR) tool and an at-bit resistivity measurement to make the casing point decision was proposed. With this new approach, all four wells were landed, with actual reservoir penetration less than 1m TVD. The real-time data from the DDR tool allowed the operator to efficiently drill the section, only reducing the rate of penetration immediately prior to entering the reservoir. The at-bit resistivity tool, drilling parameter changes and cuttings identification were beneficial to confirm reservoir entry and call section TD.
Environmental considerations for decommissioning
Authors: Hughes Kayleigh , Hisne Fairul Izmal Jamal , Su Li Yuen
Published: June 2021

The acceleration of decommissioning activities in recent times has expedited the need to decommission responsibly and sustainably. Decommissioning activities are increasingly under public scrutiny, yet in many regions there remains a lack of legislation, regulatory guidance, and practical experience in implementing decommissioning activities. In general, the decommissioning process begins with the assessment stage, followed by planning and management, and lastly the actual decommissioning execution. The best practice approach for responsible decommissioning is to conduct a best practicable environmental option (BPEO) study, which is also known as a comparative assessment and/or decommissioning options assessment. The BPEO will identify the most beneficial or least damaging option to be selected for each decommissioning project by accounting for all relevant influencing aspects such as technical, environmental and social impacts, costs, stakeholder opinions, legal compliance as well as health and safety. Such documentation is important to demonstrate that potential impacts arising from decommissioning activities have either been removed or are reduced to as low as reasonably practicable (ALARP). The best decommissioning option will vary depending on local aspects such as environmental baseline conditions, key stakeholders, waste management and disposal facilities, available technologies and the viability of all options considered including reuse (e.g. rigs to reef). This paper outlines recommended approaches for successful decommissioning planning, highlighting key environmental considerations and other important influencing factors. The aim is to demonstrate the importance of holistic thinking for the development of decommissioning strategies to establish a robust decommissioning plan and successful execution.
Improved modelling of pressure-dependent permeability behaviour in coal based on a new workflow of petrophysics, hydraulic fracturing and reservoir simulation
Authors: Ramanandraibe Honja Miharisoa , Ribeiro Ayrton Soares , Johnson Raymond , You Zhenjiang
Published: June 2021

Many coal seam gas (CSG) reservoirs (also known as coalbed methane) can have low permeability, require stimulation to produce economic rates and often exhibit pressure-dependent permeability (PDP) behaviour. Defining PDP behaviour in coal using reservoir simulation is a non-unique problem based on the uncertainty in coal properties and input parameters. Recent research demonstrated that an integrated analysis coupling of a diagnostic fracture injection test analysis, hydraulic fracture modelling and reservoir simulation can better characterise PDP behaviour in order to evaluate stimulation effectiveness in coals (Johnson et al. 2020). The present work aims to improve the recently developed model by including multilayer and permeability anisotropy effects. A reservoir model with multiple coal layers is established in a pressure-dependent reservoir simulator, based on the image log interpretations. Permeability anisotropy in the formation is realised by introducing heterogeneous distribution of permeability in different directions. Modelling results indicate effects of aspect ratio between multilayers on the pressure distribution and production history. A lower permeability anisotropy ratio yields better well productivity, and higher stimulation is required to increase the stimulated reservoir volume to maximise gas recovery. The improved model and workflow are applicable to other CSG fields for defining key variables where hydraulic fracturing performance has been unable to overcome limitations based on pressure dependency, often accompanied by low-permeability behaviour. This workflow has applications in Australia and many areas (e.g. China and India) exhibiting low-permeability and PDP behaviour and where only typically collected field data is available.
Catch me if you can: personality drives technique-specific biases during live-capture trapping
Authors: Johnstone Kyla Chloe , McArthur Clare , Banks Peter Bruce
Published: June 2021

Abstract Context Wildlife surveys often rely on a single live-capture technique to sample animal populations. Yet, animal personality (e.g. bold vs shy) can drive heterogeneity in capture probability, leading to biased sampling during live-capture trapping surveys. Aims We tested whether a personality-related capture bias is similar between two live-capture techniques, or whether techniques with different capture mechanisms are biased towards certain spectrums of personality. Methods We compared two live-capture techniques commonly used for surveying lizards, namely, noosing and pitfall traps. Techniques were deployed several days apart to survey populations of a desert-dwelling agamid, the military dragon, and we used outdoor open-field arenas to test for personality traits relating to boldness, activity and exploration. Key results We found that noosing and pitfall traps sampled distinctly different spectrums of personality, with no individuals being captured by both techniques. Unexpectedly, noosing, which involved people approaching dragons to capture them, was biased towards shyer individuals that stayed close to shelter. In contrast, pitfall traps, which were generally set in open areas, were biased towards capturing individuals that moved further from shelter. Conclusions We demonstrated that different live-capture techniques can be biased towards different spectrums of personality. We attribute the relationship between personality and technique to an interaction between the capture mechanisms of each technique and individual perceptions of risk and microhabitat use. Implications To overcome biased and selective sampling and target individuals along a broad spectrum of personality, surveys should use complementary techniques that vary in their capture mechanisms.
Competing off-loading mechanisms of meropenem from an
l,d
-transpeptidase reduce antibiotic effectiveness
Authors: Zandi Trevor A. , Townsend Craig A.
Published: June 2021

Significance

Meropenem is a broad-spectrum carbapenem antibiotic widely used in the clinic. Its inhibition of
l,d
-transpeptidase cell-wall biosynthetic enzymes is increasingly recognized as a critical aspect of its broad-spectrum activity, particularly against mycobacterial species including
Mycobacterium tuberculosis
. We have demonstrated unexpected, reversible, and nonhydrolytic off-loading reactions of meropenem with one of its key targets, Ldt
Mt2
, representative of the
l,d
-transpeptidase superfamily. These findings belie the tacit assumption of irreversible inhibition with an exclusively hydrolytic off mechanism for carbapenems against their classical target, the penicillin-binding proteins. While modestly effective against tuberculosis, existing carbapenems have not been optimized for potency against
l,d
-transpeptidases. The knowledge gained here of two nonhydrolytic off-loading mechanisms provides important insights to help guide the design and synthesis of improved carbapenems.
Pan-African evolution of within- and between-country COVID-19 dynamics
Authors: Ssentongo Paddy , Fronterre Claudio , Geronimo Andrew , Greybush Steven J. , Mbabazi Pamela K. , Muvawala Joseph , Nahalamba Sarah B. , Omadi Philip O. , Opar Bernard T. , Sinnar Shamim A. , Wang Yan , Whalen Andrew J. , Held Leonhard , Jewell Christopher , Muwanguzi Abraham J. B. , Greatrex Helen , Norton Michael M. , Diggle Peter J. , Schiff Steven J.
Published: June 2021

Significance

We created a strategy for understanding the evolution of the COVID-19 pandemic throughout the African continent. Because high-quality mobility data are challenging to obtain across Africa, the approach provides the ability to distinguish cases arising from within a country or from its neighbors. The results further show how testing capacity and social and health policy contribute to the dynamics of cases, and generate short-term prediction of the evolution of the pandemic on a country-by-country basis. This framework improves the ability to interpret and act upon real-time complex COVID-19 data from the African continent. These findings emphasize that regional efforts to coordinate country-specific strategies in transmission suppression should be a continental priority to control the COVID-19 pandemic in Africa.
Multiscale mechanics and temporal evolution of vimentin intermediate filament networks
Authors: Schepers Anna V. , Lorenz Charlotta , Nietmann Peter , Janshoff Andreas , Klumpp Stefan , Köster Sarah
Published: June 2021

Significance

The mechanical integrity of cells and their ability to adapt—for example, during wound healing or in metastasizing tumors—is largely determined by the cytoskeleton. The cytoskeleton is an intricate network of biopolymers and cross-linkers. Intermediate filaments, the softest and most extensible of the three filamentous proteins of the cytoskeleton, take the role of a safety belt for cells under strain. The mechanical properties of a network depend on several factors, such as the length and mechanical properties of the single filaments and, importantly, the interactions between filaments. Here, we use a multiscale approach to disentangle these effects, which allows for direct quantification of interaction kinetics.
DOT1L complex regulates transcriptional initiation in human erythroleukemic cells
Authors: Wu Aiwei , Zhi Junhong , Tian Tian , Cihan Ali , Cevher Murat A. , Liu Ziling , David Yael , Muir Tom W. , Roeder Robert G. , Yu Ming
Published: June 2021

Significance

DOT1L, the only H3K79 methyltransferase in human cells, forms a complex with AF10/AF17 and ENL/AF9, is dysregulated in mixed-lineage leukemia (MLLr), and is believed to regulate transcriptional elongation without direct evidence. Here, functional genomic, proteomic, and biochemical studies aimed at an understanding of the role of DOT1L in erythroleukemic cells show no major role in elongation but, surprisingly, reveal that DOT1L evidently has a role in transcriptional initiation by recruiting initiation factor TFIID and enhancing H2B mono-ubiquitination by restricting deubiquitination by the Spt-Ada-Gcn5-acetyltransferase (SAGA) complex. The results thus implicate the DOT1L complex in transcriptional initiation and raise the intriguing possibility that MLLr leukemic fusion proteins may also promote transcriptional initiation through modified DOT1L complexes.
B cell residency but not T cell–independent IgA switching in the gut requires innate lymphoid cells
Authors: Zheng Mingzhu , Mao Kairui , Fang Difeng , Li Dan , Lyu Jun , Peng Dingkang , Chen Xi , Cannon Nikki , Hu Gangqing , Han Jiajia , Zhao Keji , Chen Wanjun , Zhu Jinfang
Published: June 2021

Significance

Immunoglobulin A (IgA)–producing plasma cells, important for maintaining the homeostasis of gut flora, can be generated in both T cell–dependent and independent pathways. In this study, by using unique animal models, we demonstrate that IgA class switching can occur in a T cell– and helper-like innate lymphoid cell (ILC)–independent manner, although NKp46
-
CCR6
+
lymphoid tissue inducers are critical for the formation of lymphoid structures and B cell residency in the gut. Therefore, while lymphoid structures are required for T cell–dependent IgA switching and B cell recruitment, they are not essential for T cell–independent generation of IgA-producing plasma cells from the remaining gut B cells, indicating a fundamental mechanistic difference between T cell–dependent and independent IgA class switching.
Phytochrome A elevates plant circadian-clock components to suppress shade avoidance in deep-canopy shade
Authors: Fraser Donald P. , Panter Paige E. , Sharma Ashutosh , Sharma Bhavana , Dodd Antony N. , Franklin Keara A.
Published: June 2021

Significance

Plants can detect the proximity and density of neighboring vegetation using phytochrome photoreceptors. In shade-sensitive species, canopy cover drives stem elongation, facilitating light foraging. In deep shade, where resources are severely limited, excessive elongation growth can be detrimental to plant survival. In these conditions, phytochrome-A signaling suppresses shade avoidance. Here, we provide a molecular mechanism controlling this response. We show that phytochrome A promotes early-evening increases in the expression of the circadian-clock components
TIMING OF CAB EXPRESSION 1
(
TOC1
),
PSEUDO RESPONSE REGULATOR 7 (PRR7)
,
EARLY FLOWERING 3
(
ELF3
), and
ELF4
, encoding proteins that collectively limit hypocotyl elongation. This indicates that light signals are integrated with the circadian clock to control plant development in stressful environments.
Community benefits from !Xaus Lodge in the Kgalagadi Transfrontier Park, South Africa
Authors: Spenceley Anna
Published: June 2021

This case describes how !Xaus Lodge, a 24-bed community owned lodge in the remote Kgalagadi Transfrontier Park, provides employment and other economic opportunities to ‡Khomani San and Mier communities in South Africa. By partnering with the private operator Transfrontier Parks Destinations, the lodge has been able to access markets and generate positive returns for the state and rural community members.

Information

Snyman, S. and Spenceley, A. (2019) Private Sector Tourism in Conservation Areas in Africa. Chapter 4.3.3, Case study 25: !Xaus Lodge, South Africa. CAB International, pp. 116–119.

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Good Practices for Managing a Safe Chemical Laboratory Part 3: Safety Administration and Facilities
Authors: Wedlich Richard
Published: June 2021

The Chemical Hygiene Officer must play an active role and have a strong presence in the lab, providing feedback and expertise and keeping lines of communication open between lab workers and management. The efficient facility run with good administration reflects a superior understanding of division of labor and conflict of interest. Although the operation may be seen from the outside as a large, well-lubricated machine, it is made up of many smaller parts and “safety” is one of the key lubricants.
Face Mask Controls and Duration of Wearing: What Medical Research Can Teach the Cleanroom Manager
Authors: Sandle Tim
Published: June 2021

No mask is 100% effective. Masks are a tradeoff between bacterial and particle efficiency and user comfort, with a 97.5% bacterial filter efficiency the typical rating. Achieving this is dependent upon the mask integrity and worn correctly. This paper covers cleanroom contamination control, more recent research within the medical field has been driven by responses to the coronavirus, and some recommendations for the control of surgical face masks worn in cleanrooms.
A Humidex For The Cleanroom: Why Temperature And Humidity Control Matters
Authors: Sandle Tim
Published: June 2021

Temperature and humidity control are important factors to control within the cleanroom. For pharmaceuticals and healthcare products, this relates to three areas. The first is to avoid extremes affecting the skin of the operator, and hence the ability of the cleanroom gown to contain contamination...
A Study Into the Use of Milliflex Quantum as Rapid Microbial Detection Method for Microorganisms in Pharmaceutical...
Authors: Sandle Tim
Published: June 2021

Control of pharmaceutical water systems represents an essential part of Good Manufacturing Practice and embedded within this is the quality control testing of water systems for viable microorganisms, and subjecting the data obtained to trend analysis. This has traditionally been achieved by membrane filtration and the use of a culture medium. While such test methodologies can recover a level of the bioburden present, the incubation times are lengthy. To address the problem of time-to-result, rapid microbiological methods offer an alternative approach. One such example is the Milliflex Quantum, which is the focus of this article.
Correct scaling of the correlation length from a theory for concentrated electrolytes
Authors: Ciach A , Patsahan O
Published: June 2021

Self-consistent theory for concentrated electrolytes is developed. Oscillatory decay of the charge–charge correlation function with the decay length that shows perfect agreement with the experimentally discovered and so far unexplained scaling is obtained. For the density–density correlations, monotonic asymptotic decay with the decay length comparable with the decay length of the charge correlations is found. We show that the correlation lengths in concentrated electrolytes depend crucially on the local variance of the charge density.
On a probabilistic model for martensitic avalanches incorporating mechanical compatibility
Authors: Della Porta Francesco , Rüland Angkana , Taylor Jamie M , Zillinger Christian
Published: June 2021

Building on the work by Ballet al(2015MATEC Web of Conf.3302008), Cesana and Hambly (2018 A probabilistic model for interfaces in a martensitic phase transition arXiv:1810.04380), Torrentset al(2017Phys. Rev. E95013001), in this article we propose and study a simple, geometrically constrained, probabilistic algorithm geared towards capturing some aspects of the nucleation in shape-memory alloys. As a main novelty with respect to the algorithms by Ballet al(2015MATEC Web of Conf.3302008), Cesana and Hambly (2018 A probabilistic model for interfaces in a martensitic phase transition arXiv:1810.04380), Torrentset al(2017Phys. Rev. E95013001) we includemechanical compatibility. The mechanical compatibility here is guaranteed by usingconvex integration building blocksin the nucleation steps. We analytically investigate the algorithm’s convergence and the solutions’ regularity, viewing the latter as a measure for the fractality of the resulting microstructure. We complement our analysis with a numerical implementation of the scheme and compare it to the numerical results by Ballet al(2015MATEC Web of Conf.3302008), Cesana and Hambly (2018 A probabilistic model for interfaces in a martensitic phase transition arXiv:1810.04380), Torrentset al(2017Phys. Rev. E95013001).
Microwave diagnostics damage by parametric decay instabilities during electron cyclotron resonance heating in ASDEX Upgrade
Authors: Hansen S K , Jacobsen A S , Willensdorfer M , Nielsen S K , Stober J , Höfler K , Maraschek M , Fischer R , Dunne M
Published: June 2021

We present observations of microwave diagnostics damage in three discharges employing third-harmonic X-mode electron cylcotron resonance heating (ECRH) at the ASDEX Upgrade tokamak. In all cases, the diagnostics damage is explainable in terms of a parametric decay instability (PDI), where an X-mode ECRH wave decays to two trapped upper hybrid (UH) waves near half the ECRH frequency, followed by secondary instabilities, which generate strong microwave signals near multiples of half the ECRH frequency that cause the damage. Trapping of the UH waves near half the ECRH frequency is necessary to reduce the ECRH power required for exciting the PDIs to a level attainable at ASDEX Upgrade, and may occur when the second-harmonic UH resonance of the ECRH waves is present in a region of non-monotonic electron density, e.g. near the O-point of a magnetohydrodynamic mode or the plasma center. The diagnostics damage in the three discharges may be attributed to PDIs occurring near the O-point of a rotating mode, near the plasma center, and near the O-point of a locked mode, respectively. In the rotating mode case, the strong signals are shown to be quasi-periodic, with spikes occurring when the O-point of the mode passes through an ECRH beam, as expected. In the locked mode case, Thomson scattering profiles demonstrate the possibility of the primary PDI occurring based on experimental data for the first time under fusion-relevant conditions. Applying the framework used for ASDEX Upgrade to the X-mode ECRH scenarios planned for the early operation phase of ITER, the PDIs are found to be likely in connection with 170 GHz ECRH of half field scenarios and 104 GHz (or 110 GHz) ECRH of one third field scenarios. Finally, several strategies for mitigating diagnostics damage are proposed.
Bimodal polarons as a function of morphology in high efficiency polymer/acceptor blends for organic photovoltaics
Authors: Guo Junjun , Marin-Beloqui Jose M , Clarke Tracey M
Published: June 2021

The polymer PffBT4T-C9C13 (poly[(5,6-difluoro-2,1,3-benzothiadiazole-4,7-diyl)[3,3'''-bis(2-decyltetradecyl)[2,2':5',2'':5'',2'' -quaterthiophene]-5,5'''-diyl]]) produces organic solar cells of >11% efficiency with both fullerenes and non-fullerenes. We present a comprehensive morphology and spectroscopy study of this polymer and its blends, focusing on atomic force microscopy, x-ray diffraction, and transient absorption spectroscopy on microsecond timescales. Unusually, fullerene-induced ordering is observed, with the polymer/fullerene blend displaying a greater crystallinity compared to the pristine polymer. This was correlated with the appearance of bimodal polarons: fast-decaying polarons in the pristine amorphous polymer domains and trapped polarons localised in the fullerene-induced ordering (crystallline) domains. The lifetime of the trapped polaron was significantly enhanced upon thermal annealing, and the complex relationship observed between lifetime and film crystallinity suggest a contribution from trap states at the interfaces between ordered and disordered domains that lead to inhibited recombination. In contrast, blends incorporating the well-known analogue PffBT4T-2OD (with a shorter alkyl chain length) exhibit neither fullerene-induced ordering nor bimodal polarons. However, both PffBT4T-C9C13 and PffBT4T-2OD polymer blends show clear evidence of polymer triplet formation, which is the first time triplets have been identified in PffBT4T-based blends. In this study, we remark upon the complex relationship between morphology and the photophysics. This relationship will open the door to the synthesis of new molecules to control the blend morphology and thus optimise organic photovoltaic performance.
Socio-economic disparities and COVID-19 in the USA
Authors: Paul Ayan , Englert Philipp , Varga Melinda
Published: June 2021

COVID-19 is not a universal killer. We study the spread of COVID-19 at the county level for the United States up until the 15th of August, 2020. We show that the prevalence of the disease and the death rate are correlated with the local socio-economic conditions often going beyond local population density distributions, especially in rural areas. We correlate the COVID-19 prevalence and death rate with data from the US Census Bureau and point out how the spreading patterns of the disease show asymmetries in urban and rural areas separately and are preferentially affecting the counties where a large fraction of the population is non-white. Our findings can be used for more targeted policy building and deployment of resources for future occurrence of a pandemic due to SARS-CoV-2. Our methodology, based on interpretable machine learning and game theory, can be extended to study the spread of other diseases.