bluuebunny/crossref_metadata_2025 huggingface dataset:
Red rot of sugarcane (Colletotrichum falcatumWent)
Authors: Viswanathan Rasappa
Published: August 2022

Red rot of sugarcane was recorded more than 100 years before in Java, India, Argentina, USA and other countries, and it is one of the most devastating diseases of sugarcane. Since the cultivated sugarcane (Saccharum officinarum) has failed across the countries, systematic inter-specific hybridization betweenS. officinarumand the wild speciesS. spontaneumreferred as ‘nobilization’ was done to develop resistant varieties and the disease was managed in most of the countries. However, in the countries especially in Asia, varietal breakdown to red rot caused severe epiphytotics, by which the resistant varieties failed in the field at regular intervals. New pathogenic strains ofColletotrichum falcatumwith higher virulence were found responsible for varietal breakdown in sugarcane. Extensive cultivation of a single variety over large areas led to extensive crop damages due to ‘vertifolia’ effect in different decades in India. The current epiphytotic on the ruling variety Co 0238 has caused loss of more than one billion US dollars in the current season in the country. Detailed studies were done on pathogenic variation, epidemiology, screening methods, disease resistance mechanism, identifying effectors, pathogenicity determinants, antifungal genes and transgenics. Recently, complete genome and transcriptomes ofC. falcatumwere sequenced and pathogenicity hot spots and candidate secreted effector proteins were identified and this will further help to identify the candidate genes for further genetic manipulation. In spite of poor understanding on inheritance of resistance toC. falcatumin sugarcane, new varieties with red rot resistance were developed and deployed after each of the epiphytotic to save the crop. Further, other management practices including bioagents, chemicals and inducers were attempted and improved efficacy by mechanized sett treatment showed promising results to manage the disease under field conditions.
PPE for pesticide operators and reentry workers: achievements in France through national and international collaborations
Authors: Shaw Anugrah , Briand Olivier , Urtizberea Michel , Durand-Réville Julien , Bois-Marchand Clotilde
Published: August 2022

Plant protection products (PPP) are regulated products that require authorization in the country where they are sold. Operator and reentry worker safety when handling pesticides is one of the safety considerations that must be addressed as part of the registration process. Personal protective equipment (PPE) is one of the options for reducing operator and reentry worker exposure. Quality, comfort, cost, and availability are common constraints in the use of PPE that need to be addressed for it to be used effectively to mitigate risk. This requires stakeholders from the PPP and PPE sectors working together; it cannot be accomplished by any one group or entity alone. This process, which begins with compliance with regulations and ends with the possibility of the farmer/operator/reentry worker to protect themselves, requires a concerted effort. This article shows how international standards and expertise, as well as coordination of PPP and PPE stakeholders in France, resulted in the development and implementation of risk-based PPE requirements, which are acceptable to farmer/operator/reentry worker. The French example could be used by other countries that are governed by EU regulations. Additionally, the development of consistent labels and partnerships to promote clear consistent message has broader implications.
Theory and experiments for disordered elastic manifolds, depinning, avalanches, and sandpiles
Authors: Wiese Kay Jörg
Published: August 2022

Domain walls in magnets, vortex lattices in superconductors, contact lines at depinning, and many other systems can be modeled as an elastic system subject to quenched disorder. The ensuing field theory possesses a well-controlled perturbative expansion around its upper critical dimension. Contrary to standard field theory, the renormalization group (RG) flow involves a function, the disorder correlator Δ(w), and is therefore termed the functional RG. Δ(w) is a physical observable, the auto-correlation function of the center of mass of the elastic manifold. In this review, we give a pedagogical introduction into its phenomenology and techniques. This allows us to treat both equilibrium (statics), and depinning (dynamics). Building on these techniques, avalanche observables are accessible: distributions of size, duration, and velocity, as well as the spatial and temporal shape. Various equivalences between disordered elastic manifolds, and sandpile models exist: an elastic string driven at a point and the Oslo model; disordered elastic manifolds and Manna sandpiles; charge density waves and Abelian sandpiles or loop-erased random walks. Each of the mappings between these systems requires specific techniques, which we develop, including modeling of discrete stochastic systems via coarse-grained stochastic equations of motion, super-symmetry techniques, and cellular automata. Stronger than quadratic nearest-neighbor interactions lead to directed percolation, and non-linear surface growth with additional Kardar–Parisi–Zhang (KPZ) terms. On the other hand, KPZ without disorder can be mapped back to disordered elastic manifolds, either on the directed polymer for its steady state, or a single particle for its decay. Other topics covered are the relation between functional RG and replica symmetry breaking, and random-field magnets. Emphasis is given to numerical and experimental tests of the theory.
First-principles insights into the spin-valley physics of strained transition metal dichalcogenides monolayers
Authors: Faria Junior Paulo E , Zollner Klaus , Woźniak Tomasz , Kurpas Marcin , Gmitra Martin , Fabian Jaroslav
Published: August 2022

Transition metal dichalcogenides (TMDCs) are ideal candidates to explore the manifestation of spin-valley physics under external stimuli. In this study, we investigate the influence of strain on the spin and orbital angular momenta, effective g-factors, and Berry curvatures of several monolayer TMDCs (Mo and W based) using a full ab initio approach. At the K-valleys, we find a surprising decrease of the conduction band spin expectation value for compressive strain, consequently increasing the dipole strength of the dark exciton by more than one order of magnitude (for

∼
1
%
–
2
%

strain variation). We also predict the behavior of direct excitons g-factors under strain: tensile (compressive) strain increases (decreases) the absolute value of g-factors. Strain variations of ∼1% modify the bright (A and B) excitons g-factors by ∼0.3 (0.2) for W (Mo) based compounds and the dark exciton g-factors by ∼0.5 (0.3) for W (Mo) compounds. Our predictions could be directly visualized in magneto-optical experiments in strained samples at low temperature. Additionally, our calculations strongly suggest that strain effects are one of the possible causes of g-factor fluctuations observed experimentally. By comparing the different TMDC compounds, we reveal the role of spin–orbit coupling (SOC): the stronger the SOC, the more sensitive are the spin-valley features under applied strain. Consequently, monolayer WSe2 is a formidable candidate to explore the role of strain on the spin-valley physics. We complete our analysis by considering the side valleys, Γ and Q points, and by investigating the influence of strain in the Berry curvature. In the broader context of valley- and strain-tronics, our study provides fundamental microscopic insights into the role of strain in the spin-valley physics of TMDCs, which are relevant to interpret experimental data in monolayer TMDCs as well as TMDC-based van der Waals heterostructures.
Modified gravitational wave propagation with higher modes and its degeneracies with lensing
Authors: Ezquiaga Jose Maria , Hu Wayne , Lagos Macarena , Lin Meng-Xiang , Xu Fei
Published: August 2022

Low-energy alternatives to General Relativity (GR) generically modify the phase of gravitational waves (GWs) during their propagation. As detector sensitivities increase, it becomes key to understand how these modifications affect the GW higher modes and to disentangle possible degeneracies with astrophysical phenomena. We apply a general formalism — the WKB approach — for solving analytically wave propagation in the spatial domain with a modified dispersion relation (MDR). We compare this WKB approach to applying a stationary phase approximation (SPA) in the temporal domain with time delays associated to the group or particle velocity. To this end, we extend the SPA to generic signals with higher modes, keeping careful track of reference phases and arrival times. We find that the WKB approach coincides with the SPA using the group velocity, in agreement with the principles of wave propagation. We then explore the degeneracies between a GW propagation with an MDR and a strongly-lensed GW in GR, since the latter can introduce a frequency-independent phase shift which is not degenerate with source parameters in the presence of higher modes. We find that for a particular MDR there is an exact degeneracy for wave propagation, unlike with the SPA for particle propagation. For the other cases, we search for the values of the MDR parameters that minimize the χ2and conclude that strongly-lensed GR GWs could be misinterpreted as GWs in modified gravity. Future MDR constraints with higher mode GWs should include the possibility of frequency-independent phase shifts, allowing for the identification of modified gravity and strong lensing distortions at the same time.
Interstellar Extinction and Polarization of Stars in the Open Cluster NGC 6709
Authors: Topasna G. A. , Gibson S. D. , Kaltcheva N. T.
Published: August 2022

We present BVRI polarimetric measurements of 23 stars in the direction of the open cluster NGC 6709. Fifteen stars display wavelength-dependence of polarization which is typically due to selective extinction in the interstellar medium and could be fitted to the Serkwoski equation. Based on these stars, we obtained an average maximum degree of polarization of 0.722 ± 0.022% and an average wavelength at a maximum polarization of 0.615 ± 0.011 μm. The observed low polarization may be due to the alignment of grains along a more longitudinally-directed magnetic field in this region which would cause the aspect ratio of the grains to be reduced. This would have the observational consequence of decreased polarization as well as shifting

λ

max

toward longer wavelengths. Using the expression proposed by Whittet & van Breda we calculated the ratio of total-to-selective extinction as

R

V

=
(
5.6
±
0.3
)

λ

max

=
3.44
±
0.06

, higher than the nominal value of 3.1 for the general ISM. The remaining eight sample stars display an unusual wavelength-dependence that is similar to some Be stars. However, there are only two Be stars currently listed in this cluster, yet, based on our data, they both present reliable fits within the Serkowski equation. The overall alignment of the V-band polarization vectors implies polarization by selective extinction due to foreground dust. Using the Planck 353 GHz channel we find there is an agreement between polarization by emission and selective extinction. Since the optical polarization traces a magnetic field, this suggests that the magnetic field in this region is inclined to the Galactic plane, with an overall average Galactic position angle of 104 ± 12 (st. dev.) degrees.
Sensitivity analysis of Johnson-Cook material constants and friction coefficient to the surface residual maximum principal stress in turning Inconel 718 simulations
Authors: Peng Huachen , Tang Wencheng , Zhou Xin
Published: August 2022

The residual maximum principal stress on the surface of components affects the service life and corrosion resistance of parts. The current study focuses on the sensitivities of the Johnson-Cook (JC) constitutive constants and the friction coefficient to the surface residual maximum principal stress during turning Inconel 718 with low-level and high-level cutting parameters. Two sets of three-dimensional (3D) turning simulations and experiments are carried out under low-level and high-level cutting parameters to verify the credibility of the simulation parameter settings. Then, the above sensitivities are analyzed based on eighteen sets of 3D turning simulations designed by the Taguchi approach. When the cutting parameters are low-level, the strain hardening coefficient B is highly sensitive to the residual maximum principal stress. Besides, under high-level cutting parameters, the strain hardening coefficient B, the strain hardening index n and the thermal softening coefficient m have high sensitivities, in which the thermal softening coefficient m is the most sensitive, followed by the strain hardening coefficient B. The present work provides a direction for studying the influence of surface residual maximum principal stress on the service life of components by adjusting the JC constitutive constants and the friction coefficient.
Statistical method of pore size distribution of disordered mesoporous materials based on electron microscope imaging
Authors: Mao Tan , Su Qiang , Cheng Youliang
Published: August 2022

Mesoporous materials can efficiently treat harmful substances in wastewater by virtue of the pore structure with a high specific surface area. Currently, the characterization of the pore structure of mesoporous materials is generally obtained by physical experiments. However, due to the limitation of experimental conditions, repeated measurement experiments will waste a lot of time and may damage the pore structure. In addition, for disordered mesoporous materials with a large pore size span and irregular pore positions, it is difficult to accurately analyze the pore size distribution law with the human eye observation through electron microscope images. Aiming at this problem, this paper proposes a method to rapidly calculate the pore size distribution of materials based on SEM imaging. Firstly, the image is preprocessed. Secondly, the pore distribution information is obtained by the filling ball method, and finally the probability density curve of the pore size distribution is obtained according to the statistical method. The results show that the pore size probability density curve obtained by this method is very similar to the actual pore size distribution curve and the error is less than 11%. The proposed method provides a new direction for the analysis of disordered mesoporous materials.
Effect of nonmagnetic substrate layer island growth on the magnetism of Ag/Fe/Ag thin films
Authors: Yongguo Wang , Zhijun Wang , Qin Xu
Published: August 2022

The Ag/Fe/Ag thin films were deposited by magnetron sputtering onto glass substrates at room temperature, and the effect of coverage layer on the magnetism of Ag/Fe/Ag thin films were investigated. The results of VSM show that sample coercivity is much higher in the direction vertical to the film surface than in the direction parallel with the surface, and the structural analyses indicate that the distribution of the sample particles is more uniform. The reasons for the high coercivity were discussed, and this study attributed the changes of coercivity mainly to the sample shape anisotropy.
Study of fullerenes C126 and C156 with seven heptagon rings
Authors: Sánchez-Bernabe Francisco J.
Published: August 2022

We consider fullerenes C126 and C156, both of them with seven heptagon rings. The first of them is C126 with 19 pentagons, and 39 hexagons. It is also considered C156 with 19 pentagons, and 54 hexagons. From previous work, a couple of fullerenes, C130 and C134, are mentioned for comparative reasons. These two fullerenes also contain seven heptagon rings. Fullerene C130 is constituted of 19 pentagons, and 41 hexagons. On the other hand, fullerene C134 has 19 pentagons, and 43 hexagons. Therefore, the four fullerenes considered, with seven heptagon rings, also share the property that, the number of pentagons in each of them, is 19. This fact is a consequence of a couple of equations that relates the number of pentagons, hexagons, and heptagons contained in a fullerene. Classical fullerenes contain only pentagons and hexagons, and the more familiar example is C60 with 20 hexagons, and 12 pentagons. Actually, all classical fullerenes have 12 pentagons, regardless of how many hexagons are involved. Besides this type of molecules, there exists nonclassical fullerenes, where another type of ring is presented, like squares, or heptagons. In this paper, fullerenes with 126, 130, 134, and 156 carbons are considered, with seven heptagons, and as a consequence, all them contain 19 pentagons, and they have 39, 41, 43, and 54 hexagons, respectively. Future work would focus on finding fullerenes with a different number of carbons, and hexagons, but with 7 heptagons, and 19 pentagons. Thus, fullerene C128 of this type, should contain 40 hexagons.
The Relationship of the Polymer Molecular Structure and the Dynamic Mechanical Property Under High Pressure
Authors: Wang Wenfei , Cheng Wei , Lin Guoxing , Zhang Chunqing
Published: August 2022

The dynamic mechanical properties of the viscoelastic polymer materials are usually considered to be the key parameters for the vibration damping or acoustic materials. The relationship between the molecular structures of the random copolymer butadiene styrene rubber (SBR) obtained through the anionic polymerization method and their dynamic mechanical parameters under high pressure is studied to explore the energy loss mechanism of the polymer materials applied in the special conditions such as high pressure. The dynamic mechanical parameters were tested though experimental methods with pressure chambers, which can supply high pressure to the polymer samples. The results show that the most important effect factor of the molecular structure is the ratio of the content of the stiffer segments composed of styrene in the SSBR molecular chain to the softer ones composed of 1, 4-butadiene. This can be attributed to the stiffer segments supplying bigger free volumes for the molecular motion and higher modulus to resist to the high pressure, and the softer segments endue the effective energy loss ability to the polymer chains. However, the mass ratio of the stiffer and softer segments should be in an appropriate range, which the content of the styrene must be less than 40%.
Using scientific-grade CCDs for the direct detection of dark matter with the DAMIC-M experiment
Authors: Papadopoulos Georgios
Published: August 2022

The DAMIC-M [1] project is devoted to the exploration of the hidden sector and the search for light dark matter particles using Charge-Coupled Devices (CCDs). It follows the DAMIC at SNOLAB [2] experiment which pioneered the detection of new particles through their interaction with the nucleus or the electrons of the bulk silicon of fully depleted CCDs. A kilogram-sized target mass will be installed at the Modane underground laboratory (LSM, France) which offers an excellent low background environment for rare-event search. DAMIC-M detectors demonstrate several technological advancements including the implementation of the skipper technique, and custom front-end control and read-out electronics. Skipper CCDs can perform multiple non-destructive measurements of the pixel charge which can lead to a read-out noise of a fraction of an electron. With a 15 μm × 15 μm pixel area, 675 μm thickness and the ability of 3D reconstruction using the diffusion of the particle track, the spatial resolution of our CCDs allows for the follow-up of radioactive chains, a powerful tool to discriminate genuine particle interaction from in situ radioactive decays. Together with an extremely careful fabrication procedure that controls the contaminant and the generation of bulk radioactive contamination by cosmic ray spallation, the single electron resolution will guarantee a detection energy threshold of only a few eVs, pushing the sensitivity of DAMIC-M by at least one order of magnitude better than previous experiments. I will present the current status of DAMIC-M describing our technological challenges and the solutions we have adopted. I will introduce our method to measure and mitigate the bulk radioactive contamination and discuss the ongoing assembly of a prototype detector, the Low Background Chamber (LBC), aiming at validating our design options.
The CMS Barrel Calorimeter Processor demonstrator (BCPv1) board evaluation
Authors: Loukas N. , Goadhouse S. , Anderson T. , Belloni A. , Gorski T. , Grassi T. , Hakala J. , Hirosky B. , Jessop C. , Lutton L. , Madorsky A. , Mariano J. , Marinelli N. , Moreno L. , Svetek A. , Tikalsky J. , Wa Ho K.
Published: August 2022

For the CERN LHC phase 2, the barrel region of the CMS electromagnetic (ECAL EB) and hadronic calorimeters (HCAL HB) require new back-end electronics for their readout. To this purpose, a first version of the ATCA-based blade, the Barrel Calorimeter Processor (BCPv1), has been developed. The performance of the optical links as well as clock distribution are also presented here. The BCPv1 has been tested together with front-end and trigger boards, as well as with the new DAQ and TCDS Hub (DTH) [1], to demonstrate that the BCPv1 meets the required specifications.
Measurement of energy differential spectrum of cosmic-ray muons below 400 MeV
Authors: Sato Hikaru , Kin Tadahiro , Giammanco Andrea
Published: August 2022

Recent applications of cosmic-ray muons require accurate
modeling of their flux at low energy. However, only a few
measurements have been reported below 400 MeV. Therefore, we
developed a full-absorption muon energy spectrometer (FAMES) to obtain
energy differential flux below 400 MeV. Because our main detector
can measure muon energies below 75 MeV, an energy degradation
method is adopted (using 5- and 20-cm thick lead blocks) to shift
the sensitive energy range. Three measurements were performed (in
the normal mode and the two energy degrading modes) for around two
weeks. The measurement results were compared with PARMA, an
analytical model for estimating terrestrial cosmic-ray fluxes nearly
anytime and anywhere in the world. As a result, we found that the
model can precisely predict the flux except its lower energy part.
Troubleshooting of the beam dump problem caused by helium vessel pressure fluctuation during the cryogenic adsorber regeneration process of a superconducting RF system for synchrotron user facilities
Authors: Joo Youngdo , Sohn Younguk , Park Sehwan , Lee Mujin , Kim Junghoon , Lee Yongseok , Lee Mooneon , Park Insoo
Published: August 2022

The Pohang Light Source-II (PLS-II) is a synchrotron
user-service facility that should provide a user-service period of
190 days per year with stable operation. A series of beam dump
problems related to the superconducting radio-frequency (SRF) system
but of unknown cause occurred twenty-five times from 2016 to 2018,
which severely degraded the stable operation of the PLS-II and the
SRF system. Intensive investigation has shown that the relevant beam
dumps occurred when the helium (He) flow control valves operated
momentarily during the adsorber regeneration process of the
cryogenic system. As the control valves operate momentarily, the He
vessel pressure of the cryomodule instantaneously fluctuates, and
the resonance frequency of the SRF cavity accordingly changes. If
the instantaneous change in the resonance frequency is larger than
the low-level RF (LLRF) control ability, then incorrect handling of
LLRF control occurs, resulting in a beam dump. The instantaneous
changes in the He vessel pressure occur via three different
mechanisms. Solutions for each beam dump mechanism were proposed and
implemented. After each solution was carried out, no beam dump
occurred during the adsorber regeneration process. The relation
between the He vessel pressure and the resonance frequency of the
SRF cavity was also studied to see how the solution works.
Fabrication, morphological, mechanical and biological performance of 3D printed poly(ϵ-caprolactone)/bioglass composite scaffolds for bone tissue engineering applications
Authors: Barbosa Talita V , Dernowsek Janaina A , Tobar Raul J R , Casali Bruna C , Fortulan Carlos A , Ferreira Eduardo B , Selistre-de-Araújo Heloisa S , Branciforti Marcia C
Published: August 2022

Several techniques, such as additive manufacturing, have been used for the manufacture of polymer-ceramic composite scaffolds for bone tissue engineering. A new extruder head recently developed for improving the manufacturing process is an experimental 3D printer Fab@CTI that enables the use of ceramic powders in the processing of composite materials or polymer blends. Still, the manufacturing process needs improvement to promote the dispersion of ceramic particles in the polymer matrix. This article addresses the manufacture of scaffolds by 3D printing from mixtures of poly(ϵ-caprolactone) (PCL) and a glass powder of same composition of 45S5Bioglass®, labeled as synthesized bioglass (SBG), according to two different methods that investigated the efficiency of the new extruder head. The first one is a single extrusion process in a Fab@CTI 3D printer, and the other consists in the pre-processing of the PCL-SBG mixture in a mono-screw extruder with a Maddock® element, followed by direct extrusion in the experimental Fab@CTI 3D printer. The morphological characterization of the extruded samples by scanning electron microscope showed an architecture of 0°/90° interconnected struts and suitable porosity for bone tissue engineering applications. Scaffolds fabricated by two methods shows compressive modulus ranging from 54.4 ± 14.2 to 155.9 ± 20.4 MPa, results that are compatible to use in bone tissue engineering. Cytotoxicity assays showed non-toxic effects and viability for in vitro MG-63 cell proliferation. Alizarin Red staining test showed calcium deposition in all scaffolds, which suggests PCL/SBG composites promising candidates for use in bone tissue engineering. Results of cell morphology suggest more cell growth and adhesion for scaffolds fabricated using the pre-processing in a mono-screw extruder.
Persistent effect of temperature on GDP identified from lower frequency temperature variability
Authors: Bastien-Olvera B A , Granella F , Moore F C
Published: August 2022

It is well established that temperature variability affects a range of outcomes relevant to human welfare, including health, emotion and mood, and productivity across a number of economic sectors. However, a critical and still unresolved empirical question is whether temperature variation has a long-lasting effect on economic productivity and, therefore, whether damages compound over time in response to long-lived changes in temperature expected with climate change. Several studies have identified a relationship between temperature and gross domestic product (GDP), but empirical evidence as to the persistence of these effects is still weak. This paper presents a novel approach to isolate the persistent component of temperature effects on output using lower frequency temperature variation. The effects are heterogeneous across countries but collectively, using three different GDP datasets, we find evidence of persistent effects, implying temperature affects the determinants of economic growth, not just economic productivity. This, in turn, means that the aggregate effects of climate change on GDP may be far larger and far more uncertain than currently represented in integrated assessment models used to calculate the social cost of carbon.
Uncertainty in land carbon budget simulated by terrestrial biosphere models: the role of atmospheric forcing
Authors: Hardouin Lucas , Delire Christine , Decharme Bertrand , Lawrence David M , Nabel Julia E M S , Brovkin Victor , Collier Nathan , Fisher Rosie , Hoffman Forrest M , Koven Charles D , Séférian Roland , Stacke Tobias
Published: August 2022

Global estimates of the land carbon sink are often based on simulations by terrestrial biosphere models (TBMs). The use of a large number of models that differ in their underlying hypotheses, structure and parameters is one way to assess the uncertainty in the historical land carbon sink. Here we show that the atmospheric forcing datasets used to drive these TBMs represent a significant source of uncertainty that is currently not systematically accounted for in land carbon cycle evaluations. We present results from three TBMs each forced with three different historical atmospheric forcing reconstructions over the period 1850–2015. We perform an analysis of variance to quantify the relative uncertainty in carbon fluxes arising from the models themselves, atmospheric forcing, and model-forcing interactions. We find that atmospheric forcing in this set of simulations plays a dominant role on uncertainties in global gross primary productivity (GPP) (75% of variability) and autotrophic respiration (90%), and a significant but reduced role on net primary productivity and heterotrophic respiration (30%). Atmospheric forcing is the dominant driver (52%) of variability for the net ecosystem exchange flux, defined as the difference between GPP and respiration (both autotrophic and heterotrophic respiration). In contrast, for wildfire-driven carbon emissions model uncertainties dominate and, as a result, model uncertainties dominate for net ecosystem productivity. At regional scales, the contribution of atmospheric forcing to uncertainty shows a very heterogeneous pattern and is smaller on average than at the global scale. We find that this difference in the relative importance of forcing uncertainty between global and regional scales is related to large differences in regional model flux estimates, which partially offset each other when integrated globally, while the flux differences driven by forcing are mainly consistent across the world and therefore add up to a larger fractional contribution to global uncertainty.
Extinction and hybridization in a neutral model of speciation
Authors: Botelho Larissa Lubiana , Darcie Marquitti Flavia Maria , de Aguiar Marcus A M
Published: August 2022

Evolution is usually pictured as a tree where ancient species branch into new ones and eventually disappear. In this simplified view, the balance between speciation and extinction fully determines the diversity of life. Hybridization, however, introduces another level of complexity, allowing neighboring branches of the tree to interact, mixing their genetic content. This generates further diversity leading to reticulated trees. In this paper we study processes of speciation, extinction and hybridization using a genetically and spatially explicit neutral model of diversification. The model is based on the Derrida–Higgs formulation, where the genome of haploid individuals is represented by binary strings and reproduction is constrained by genetic similarity. Tracking all events of speciation, extinction and hybridization throughout the evolutionary process allows us to compute complete and exact phylogenetic trees. We found that genome size played a key role in these processes, increasing the extinction rate and decreasing the hybridization rate. Only in the limit of large genomes the simplified picture of a branching tree is recovered. Most hybridization events occurred between relatively abundant species, discarding lack of sexual partners or small population sizes as potential causes. We found that hybridization occurred mostly because of opportunity (genetic similarity and spatial proximity) between recently branched species, when the number of accumulated mutations is not yet too large.
Stochasticity of infectious outbreaks and consequences for optimal interventions
Authors: Morán-Tovar Roberto , Gruell Henning , Klein Florian , Lässig Michael
Published: August 2022

Global strategies to contain a pandemic, such as social distancing and protective measures, are designed to reduce the overall transmission rate between individuals. Despite such measures, essential institutions, including hospitals, schools, and food producing plants, remain focal points of local outbreaks. Here we develop a model for the stochastic infection dynamics that predicts the statistics of local outbreaks from observables of the underlying global epidemics. Specifically, we predict two key outbreak characteristics: the probability of proliferation from a first infection in the local community, and the establishment size, which is the threshold size of local infection clusters where proliferation becomes likely. We derive these results using a contact network model of communities, and we show how the proliferation probability depends on the contact degree of the first infected individual. Based on this model, we suggest surveillance protocols by which individuals are tested proportionally to their degree in the contact network. We characterize the efficacy of contact-based protocols as a function of the epidemiological and the contact network parameters, and we show numerically that such protocols outperform random testing.
Impact of air pollution exposure on lung function and exhaled breath biomarkers in children and adolescents
Authors: Carraro Silvia , Ferraro Valentina Agnese , Zanconato Stefania
Published: August 2022

A growing number of scientific papers focus on the description and quantification of the detrimental effects of pollution exposure on human health. The respiratory system is one of the main targets of these effects and children are potentially a vulnerable population. Many studies analyzed the effects of short- and long-term exposure to air pollutants on children’s respiratory function. Aim of the present narrative review is to summarize the results of the available cohort studies which investigated how lung function of children and adolescents is affected by exposure to air pollution. In addition, an overview is provided on the association, in children, between pollution exposure and exhaled breath biomarkers, as possible indicators of the pathogenetic mechanisms involved in pollution-related lung damages. The identified cohort studies suggest that, beside the possible impact of recent exposure, early and lifetime exposure are the variables most consistently associated with a reduction in lung function parameters in both children and adolescents. As for the effect of air pollution exposure on exhaled breath biomarkers, the available studies show an association with increased exhaled nitric oxide, with increased concentrations of malondialdehyde and 8-isoprostane in exhaled breath condensate (EBC), and with EBC acidification. These studies, therefore, suggest lung inflammation and oxidative stress as possible pathogenetic mechanisms involved in pollution related lung damages. Taken together, the available data underscore the importance of the development and application of policies aimed at reducing air pollutant concentration, since the protection of children’s lung function can have a beneficial impact on adults’ respiratory health in the future.
Revisiting the phase transformations involving Cu6Sn5 intermetallic: resolving local domain structures induced by ordering
Authors: Martin S , Winkelmann A , Leineweber A
Published: August 2022

Cu6Sn5 is one of the most important intermetallics present in solder joints based on Cu and Sn. Due to still uncertain reasons for failure of these joints, detailed microstructural research can help to figure out the underlying mechanisms. For Cu- and as well for Sn-rich environments of the Cu6Sn5 the microstructural occurrence of the phase transformations are investigated. During the formation of stable η′ from the disordered high temperature η phase the formation of metastable modulated incommensurately ordered η′′ takes place. For the copper rich samples long-range ordering and twin-related domain formation within η′′ was observed. Although conventional Hough-based EBSD analysis was not able to identify the correct domain orientation, Kikuchi pattern matching using simulated patterns was able to resolve the correct microstructure. As ordered intermetallics tend to be brittle in nature, the current microstructure research provides a basis to investigate unresolved problems in the initiation of failure.
Simulated migration behavior of metastable Σ3 (11 8 5) incoherent twin grain boundaries
Authors: Homer Eric R , Verma Akarsh , Britton Darcey , Johnson Oliver K. , Thompson Gregory B.
Published: August 2022

Molecular dynamics simulations are used to examine the migration behavior of one incoherent twin, a Σ3 (11 8 5) / (8 11 5) grain boundary. The boundary is known to exhibit non-Arrhenius boundary migration that slows as temperature increases. This behavior is examined in 165 metastable structures of the same boundary and in a large simulation cell where smaller length scales can have less of an effect. The metastable boundaries show diverse migration behaviors from non-Arrhenius to Arrhenius, though the majority of them exhibit non-Arrhenius behavior. The large simulation cell sizes show no dependence on system size, eliminating concerns about the effect of facet nucleation on the migration in periodic simulation cells. However, facet structures play an important role in the migration of the metastable boundaries. Boundaries with larger facets typically migrate faster than those with smaller facets and with defects in the boundary structure.
Synthesis, characterization, and dealloying of Al-Cu alloys prepared using spark plasma sintering
Authors: Sun S , Zhang C F , Gao W Q , Godfrey A
Published: August 2022

A series of Al-Cu alloys were prepared using spark plasma sintering by adjusting the initial composition ratio and powder sizes. The resulting phase and microstructure in these samples were investigated by X-ray diffraction, as well as energy-dispersive spectroscopy and electron back-scatter diffraction of samples examined in the scanning electron microscope. Both the initial composition ratio and powder size affect the phase composition and phase distribution of the sintered samples. Smaller size powders lead to formation of near-equilibrium phase structures, while larger initial powders lead to metastable microstructures containing phases that deviate significantly from the phase diagram. Dealloying of a metastable microstructure was observed to result in the formation of hierarchical skeleton nanoporous Cu structure.
Heterogeneous lamellar-structured high manganese steel with excellent tensile properties
Authors: Xiong J C , Zhao J F , Kong L , Yang H K , Zhang X D , Wang Y H
Published: August 2022

A single-phase Fe-30Mn-0.11C steel with a heterogeneous lamellar structure composed of micron-sized recrystallized grains (MRGs) and deformation bands (DBs) was successfully produced by cold rolling to 90% in thickness reduction and annealing at 550 °C for 120 min. The tensile properties of samples cut out along the rolling direction (RD) and transverse direction (TD) were investigated. The results indicate that the samples along the RD and TD both exhibit excellent tensile properties, with a yield strength of approximately 600 MPa and a total elongation of more than 30%.
3D grain mapping by laboratory X-ray diffraction contrast tomography implemented on a conventional tomography setup
Authors: Fang H , Granger R , Ludwig W , Lhuissier P
Published: August 2022

Non-destructive 3D characterization of grain orientations, shapes and sizes, i.e. grain mapping, offers immense opportunities for studying microstructural evolution in polycrystalline materials. In addition to a number of well-established grain mapping techniques available at synchrotron facilities, a polychromatic variant - laboratory diffraction contrast tomography (LabDCT) - using lab-based x-rays, has been developed and commercialized. Yet, the product is bounded to a specific instrument and requires a commercial license, which limits the use on widely available laboratory instruments. To promote the availability of LabDCT, we have developed a grain reconstruction method and implemented it on a conventional X-ray tomography setup at the SIMaP laboratory for LabDCT grain mapping. First, we tested the grain reconstruction algorithm by comparing an input virtual grain structure and a reconstructed volume using the forward simulated diffraction projections from the input structure. Then, we experimentally characterized an AlCu alloy sample using LabDCT and validated the grain mapping result by a grain reconstruction from synchrotron DCT measurement. Last, perspectives on further development of generalizing LabDCT technique on conventional tomography setups are discussed.
Separation of XRD peak profiles in single-phase metals with bimodal grain structure to analyze stress partitioning
Authors: Sjögren-Levin E , Pantleon W , Ahadi A , Hegedüs Z , Lienert U , Tsuji N , Ameyama K , Orlov D
Published: August 2022

Materials with bimodal grain size distributions have an attractive combination of strength and ductility. Harmonic structure materials are a category of bimodal-structure materials with a specific microstructure design. The deformation mechanisms of such novel materials during the early stages of deformation are not well understood. Thus, we deformed nickel with harmonic structure in tension until a true strain of 0.04 while recording powder diffraction patterns with high-energy synchrotron X-rays. Line profile analysis based on such data enables quantification of stress states and lattice defect densities in different phases in multi-phase materials. Bimodal size distributions in single-phase materials add extra complexity due to the absence of differences in composition and crystal structure causing the diffraction peaks from fine and coarse grains to appear at the same diffraction angles. Therefore, prior to any meaningful line profile analysis, the respective diffraction profiles need to be separated. A general method for automatically separating profiles originating from different grain fractions in bimodal materials is presented in this work.
Stress relief during annealing of railway wheel steel characterized by synchrotron X-ray micro-diffraction
Authors: Zhang Yubin , Jessop Casey , Nikas Dimitrios , Yu Tianbo , Liu Wenjun , Ahlström Johan
Published: August 2022

Railway wheels in service experience rolling contact fatigue loading, but also need to resist frictional heating on braking, yielding temperatures up to 500 °C. The combination of mechanical and thermal loads leads to changes in the mechanical properties of the material. The focus of this study is to investigate the effect of annealing on local microstructure and residual stresses in railway wheel pearlitic steel (medium carbon steels, ~0.55 wt.% C) using synchroton X-ray Laue micro-diffraction. It is found that the local residual stress releases to a large extent after annealing at 500 °C. The stress formation and relief mechanisms and their relationship to the local microstructure are discussed.
Recovery of small orientation gradients in a recrystallized grain observed in 3D during ex-situ annealing
Authors: Hong Chuanshi , Zhang Yubin , Yu Tianbo , Liu Wenjun , Jensen Dorte Juul
Published: August 2022

We report the observation of a small orientation gradient (~0.5° over a few micrometers) in a recrystallized grain formed at the sample surface in pure Al and the elimination of this orientation gradient during subsequential ex-situ annealing. The observation is in 3D and done using synchrotron white-beam differential-aperture X-ray microscopy with high angular resolution of 0.01°. The elimination of the orientation gradient during subsequent annealing are analyzed and discussed.
A polarization-insensitive triple-band perfect metamaterial absorber incorporating ZnSe for terahertz sensing
Authors: Abdulkarim Yadgar I , Alkurt Fatih Özkan , Bakır Mehmet , Awl Halgurd N , Muhammadsharif Fahmi F , Karaaslan Muharrem , Appasani Bhargav , Al-Badri Khalid Saeed Lateef , Zhu Yuanyuan , Dong Jian
Published: August 2022

In this work, a triple-band polarization-insensitive metamaterial structure with perfect absorption is proposed by incorporating a zinc selenide (ZnSe) spacer. The structure was optimally designed by varying the type of the spacer and the unit cell dimensions. The structure was simulated using the finite integration technique, and the results showed that the proposed design achieved a near-perfect absorption of about 99%, 99%, and 100% at 22.50, 28.98, and 35.14 THz, respectively. Its absorption characteristics were insensitive to the polarization angle and a wide range of incidence angles, making it an ideal absorber. Further investigations of the electric field, magnetic field, and surface current distributions were carried out to elaborate on the absorption characteristics at various resonance frequencies. The proposed device can also be used as a sensor that can detect the depth of the surrounding analyte and its refractive index. The device could detect the depth of the analyte with a peak sensitivity of 2.76 THz μm−1 and its refractive index with a peak sensitivity of 1.55 THz RIU−1. Thus, the design could have interesting terahertz applications.
Chaperone requirements for de novo folding of Saccharomyces cerevisiae septins
Authors: Hassell Daniel , Denney Ashley , Singer Emily , Benson Aleyna , Roth Andrew , Ceglowski Julia , Steingesser Marc , McMurray Michael
Published: August 2022

Septin proteins evolved from GTPases and form cytoskeletal filaments. Other cytoskeletal NTPases (actin and tubulins) require molecular chaperones to fold. Many chaperones bind septins, but functional requirements were unknown. A combination of in vivo and in vitro analyses found roles for specific chaperones in efficient folding of yeast septins.
Acetyl-L-carnitine attenuates Poly I:C-induced sickness behavior in mice
Authors: Miura Suzuka , Oyanagi Eri , Watanabe Chihiro , Hamada Hiroki , Aoki Takafumi , Kremenik Michael J , Yano Hiromi
Published: August 2022

Fatigue is accompanied by a decrease in physical activity or malaise, and might be reduced by acetyl-L-carnitine (ALC) administration. The purpose of this study was to investigate the preventive effects of ALC on Poly I:C-induced sickness behavior in mice. For the experiment, male C3H/HeN mice were used and treated with ALC for 5 days before Poly I:C administration. ALC administration attenuated the decrease in wheel behavior activity of mice at 24 h after Poly I:C administration and ALC-treated mice quickly recovered from the sickness behavior. The gene expression of brain-derived neurotrophic factor (BDNF) in the cerebrum and hippocampus, which is associated with physical activity, was higher in the ALC-treated group. Translocator protein 18kDa (TSPO), which has cytoprotective effects, was up-regulated in the cerebrum and hippocampus, suggesting that ALC suppressed the decrease in activity induced by Poly I:C treatment through enhancement of cytoprotective effects in the brain.
Stability of hen egg-white lysozyme during embryonic development
Authors: Muroi Yukiko , Aburaya Izumi , Kiyokawa Yuki , Watanabe Keiichi , Wada Koji , Abe Yoshito , Sugimoto Yasushi
Published: August 2022

It is of interest to determine whether and how egg-white proteins are maintained in fertile eggs. We previously observed that egg-white ovalbumin attained high stability during embryogenesis. Herein, we observed that the total mass of egg white and that of its gross protein content showed a decrease according to the days of incubation. The total bacteriolytic activity also lowered, in accord with previous observations. We purified lysozyme from egg-white samples on several incubation days. These purified lysozyme proteins were observed to have enzymatic and bacteriolytic activities against Micrococcus lysodeikticus as well as growth-inhibition potency against Staphylococcus aureus. As the embryogenesis proceeded, the purified lysozyme showed changes in Km and Vmax, a small decrease in the denaturation temperature, and symptoms of an increase in surface hydrophobicity. These results indicate that the lysozyme protein maintained its enzymatic and antibacterial activities until the late period of incubation while undergoing slight conformational changes.