bluuebunny/crossref_metadata_2025 huggingface dataset:
FEM-Simulation of the electrode temperature distribution and crater formation. Part II: Arc and glow phases of an electrical discharge
Authors: Soldera F. , Mücklich F.
Published: July 2021

A FEM model was developed to simulate the temperature increase in the material due to the power input of a discharge, which is composed of three different phases: breakdown, arc and glow discharge. In this paper the results for the arc and the glow discharge are dealt with. The model is based on the heat diffusion equation and considers phase transformations. A molten and an evaporated region were simulated and their dimensions were compared with the dimensions of craters made on polished Pt-samples (in air at 1 and 9 bar, with electrode gap of 2 mm). The electrical energy was calculated with the voltage and current curves. Using results of calorimetric investigations published in literature, the fraction of energy absorbed by the electrodes was estimated. The best results of the simulated regions for the arc were obtained for the lower values of energy input. For the largest energies, the evaporated region is overestimated. The molten and evaporated regions are hemispherical and deeper than the craters, which present a flat shape. The glow discharge produces a temperature increase in the electrode of only 1.8 degree, because the energy is distributed in a large area of the cathode.
Simulations of heat transfers in an autoclave. Applications to the curing of composite material parts
Authors: Salagnac P. , Dutournie P. , Glouannec P.
Published: July 2021

In this work, a small diameter autoclave for curing of composite material parts is studied. The particularity of this study arises from the heat exchanges, which are mainly free convection and radiation. The part is set in the matrix and it must respect a thermal cycle. It is necessary to take into account the different constraints connected to the use of the autoclave and the thermal behaviour of the matrix (limitation of tubular steel and matrix temperatures, temperature gradient in the curing part). This work is devoted to determinate the temperature profile in a section of the autoclave by numerical simulations realised by using the software package Fluent©. The taking different heat exchanges into account and the reticulation reaction heat contribution allow know the material temperature repartition during the curing. The aim is to propose solutions for minimising thermal gradients in the part and obtaining good mechanical specifications. In the simulations, we can observe a non-thermal homogeneity in the matrix and the autoclave because of the complexity of heat transfers and the particular geometry. These tests show the necessity to control the tubular steel temperature and in other part to make a good conception of the matrix configuration.
Influence of transformation plasticity on residual stresses and distortions due to the heat treatment of steels with different carbon contents
Authors: Franz C. , Besserdich G. , Schulze V. , Müller H. , Löhe D.
Published: July 2021

The simulation of manufacturing processes is more and more becoming an important tool in simultaneous engineering. The aim is to cut the time necessary for development and to optimise processes by simulation of the complete manufacturing chain. The field of heat treatment offers a large variety of applications for the use of simulation tools. Heat treatment of steels always includes the development of residual stresses and distortions. The geometry of the part, the composition of the material, the heat treatment process as well as the initial state of the part interact with each other in complex ways and have an influence on the distortion of the part. Using simulation the temporal development of temperature, phases, stresses and distortions while quenching as well as the residual stress distribution and distortion after quenching can be calculated. Transformation plasticity has been proved to be very important for heat treatment simulation. Three steels with identical contents of alloying elements but different carbon contents of 0.2, 0.5 and 0.8 wt.-% were analysed. The transformation plasticity constants for the martensitic transformation under tensile as well as compressive stresses were determined by quenching hollow specimen with nitrogen. Distortions and residual stresses were examined experimentally with cylinders made out of the three steels. Additionally, simulations of the quenching process of the cylinders were taken into account in the analysis of the experimental findings.
A model for the run out table cooling in a compact rolling mill
Authors: Hernandez L. , Guerrero-Malta M. P. , Leduc L. A. , Colas R.
Published: July 2021

A fundamental part of hot rolling of steel strip processing takes place in the run out table of industrial mills. It is in this place that most of the material transforms from austenite to ferrite. Cooling of the steel strip is promoted by high and low pressure water jets coming from different types of headers. The efficiency of such headers depends on the type of header, their flow and position, as well as the speed at which the strip is delivered from the rolling mill. Computer simulation is carried out by means of a two-dimensional finite difference model that takes into account the number, flow, position and type of headers used along the run out table. It is found that the cooling capacity of the headers is affected by the velocity of the hot rolled steel strip.
Fluidized bed heat treatment of aluminum cast components
Authors: Apelian D. , Chaudhury S. K.
Published: July 2021

Heat Treatment and post casting treatments of cast components has always been an important step in the control of microstructure, and resultant properties. In the past, the solutionizing, quenching and ageing process steps may have “required” in total over 20 hours of processing time. With the advent of fluidized bed reactors (FB), processing time has been dramatically reduced. For example, instead of 8-10 hours solutionizing time in a conventional furnace, the time required in FB is less than an hour. Experiments with Al-Si-Mg alloy, (both modified with Sr, and unmodified) were performed, having different diffusion distances (different DAS), and for different reaction times and temperatures. Both the model and the experimental results are presented and discussed.
Experimental validation of a predictive model for numerical simulation of thermo-metallurgical phenomena during electron beam welding
Authors: Carin M. , Rogeon Ph. , Carron D. , Lemasson Ph. , Couedel D. , Dumons M. , Costa J. , Bertet R. , Parpillon J.-C. , Bocquet P. , Gauthier M.
Published: July 2021

In the present work, thermal cycles measured with thermocouples embedded in specimens are employed to validate a numerical thermometallurgical model of an Electron Beam welding process. The implemented instrumentation techniques aim at reducing the perturbations induced by the sensors in place. A comparison between simulations performed on finite element code SYSWELD and the experimental measurements carried out on 16MnNiMo5 steel in the case of a partial penetration is achieved. This comparison is based on thermal cycles and also on microstructural evolutions, shapes of fusion zone (FZ) and heat affected zone (HAZ).
Studies of the thermo-mechanical material response of a Boron steel by inverse modelling
Authors: Åkerström P. , Oldenburg M.
Published: July 2021

In numerical forming simulations of the hot stamping process, the lack of reliable material data, especially at higher temperatures gives quite rough estimations of the stamping forces, strains, residual stresses and achieved final product shape. Traditionally, the material is characterised by several isothermal compression or tension tests at elevated temperatures and strain rates. The present work have pointed out an alternative/complementary approach to reduce the number of experiments and to obtain good results by using Gleeble compression tests at continuous cooling with different compression start temperatures. The isothermal mechanical response was established by means of inverse modeling, with start values obtained from isothermal test results. Three different functions describing the flow stress as function of temperature and plastic strain have been tested and compared in usefulness for the steel grade used. The main object function consists of three parts, one from each compression start temperature. The object function in the inverse problem is based on the deviation in compression force-displacement data and radial displacement at the mid point of the specimen. Minimisation of the objective function with respect to the material parameters were performed using an in-house optimization software which is based on the subplex method. The established material response has been evaluated by comparison with data from a separate forming test. For the boron steel in the austenitic phase, the Nemat-Nasser model was found to describe the material response with acceptable agreement within the temperature and strain interval studied in the experimental validation.
Energy stable modeling of two-phase flow in porous media with fluid–fluid friction force using a Maxwell–Stefan–Darcy approach
Authors: Kou Jisheng , Du Shigui , Zhong Zhen
Published: July 2021

Two-phase incompressible flow in porous media plays an important role in various fields including subsurface flow and oil reservoir engineering. Due to the interaction between two phases flowing through the pores, the fluid–fluid friction force may have a significant effect on each phase velocity. In this paper, we propose an energy stable (thermodynamically consistent) Maxwell–Stefan–Darcy model for two-phase flow in porous media, which accounts for the fluid–fluid friction. Different from the classical models of two-phase flow in porous media, the proposed model uses the free energy to characterize the capillarity effect. This allows us to employ the Maxwell–Stefan model to describe the relationships between the driving forces and the friction forces. The driving forces include the pressure gradient and chemical potential gradients, while both fluid–solid and fluid–fluid friction forces are taken into consideration. Thermodynamical consistency is the other interesting merit of the proposed model; that is, it satisfies an energy dissipation law and also obeys the famous Onsager's reciprocal principle. A linear semi-implicit numerical method is also developed to simulate the model. Numerical simulation results are provided to show that the fluid–fluid friction force can improve the oil recovery substantially during the oil displacement process.
Numerical study of the shock wave and pressure induced by single bubble collapse near planar solid wall
Authors: Yang Xiaobin , Liu Cheng , Wan Decheng , Hu Changhong
Published: July 2021

Bubble collapse is one of the leading causes for the cavitation erosion of submerged structures. For better understanding of the destructive mechanism of cavitation, high-fidelity simulation is performed to simulate the complete process of single bubble collapse near a planar solid wall. The wave propagation method with the approximate Riemann solver Harten Lax and van Leer Contact is adopted to solve the compressible two-phase five-equation model. We implement fifth-order weighted essentially non-oscillatory scheme with the block-structured adaptive mesh method to resolve shock waves and moving interface with high-resolution. We simulate single bubble collapsing in free-field to validate the present numerical methods and solver. Our results (e.g., averaged bubble-interior pressure and the radius variation) are found in excellent agreement with the theoretical Keller–Miksis solutions. In this study, the shock wave transmitted inside the bubble and the water-hammer shock formed in the liquid are under quantitative investigation. Numerical results reveal that the interactions between the shock wave and bubble interface give rise to peak pressures of liquid phase, and the initial stand-off distances have important influence on shock wave pattern, wall peak pressure, and bubble dynamics.
A length scale approach to the highest standing water wave
Authors: Tyvand Peder A. , Nøland Jonas Kristiansen
Published: July 2021

The highest standing surface wave at infinite depth is a classical hydrodynamic problem, illuminated by Taylor's excellent experiments [G. I. Taylor, “An experimental study of standing waves,” Proc. R. Soc. London, Ser. A 218, 44–59 (1953)]. Based on length scale arguments, we present a compact analytical approach to the highest standing wave. Our physical postulate is that the highest deep-water wave has a single length scale, i.e., its wavelength. The single-scale postulate for standing periodic deep-water waves is confronted with two distinctly different cases where zero and two length scales are postulated as follows: (i) No physical length scale for an isolated rogue-wave peak at deep water suggests a similarity solution. (ii) Two length scales for the periodic peaked surface at constant depth suggest a one-parameter family of standing waves. Moreover, the two length scales are the wavelength and average fluid depth. The deep-water limit with its single-length scale postulate confirms Grant's theory [M. A. Grant, “Standing Stokes waves of maximum height,” J. Fluid Mech. 60, 593–604 (1973)], taking the highest standing wave as a state of zero kinetic energy. The reversible motion is irrotational according to Lord Kelvin's theorem. The acceleration field for the highest deep-water wave has a single Fourier component according to our single length scale postulate. The resulting free-surface shape follows from the exact nonlinear dynamic condition. Our analytical theory confirms the ratio 0.203 for maximal wave height to wavelength, found by Grant. We test its robustness by extending the theory to a moderate spatial quasi-periodicity. Appendix A provides a simple proof for the right-angle peak, representing a regular extremal point of a locally quadratic complex function. Appendix B presents a quadrupole solution for an isolated peak of stagnant deep-water rogue waves.
Divergence among rice cultivars reveals roles for transposition and epimutation in ongoing evolution of genomic imprinting
Authors: Rodrigues Jessica A. , Hsieh Ping-Hung , Ruan Deling , Nishimura Toshiro , Sharma Manoj K. , Sharma Rita , Ye XinYi , Nguyen Nicholas D. , Nijjar Sukhranjan , Ronald Pamela C. , Fischer Robert L. , Zilberman Daniel
Published: July 2021

Significance

Plant gene imprinting (allele-specific chromatin modification) results in parent-of-origin–dependent expression in endosperm, a nutritive tissue essential for embryo viability. Imprinted genes function in species reproductive isolation by causing embryo abortion in crosses. We analyzed the evolution of rice gene imprinting using four cultivars spanning domestication and the divergence of two subspecies 9,000 and 300,000 y ago, respectively. Most imprinted genes are imprinted across cultivars and enriched in regulatory functions. However, approximately 10% of imprinted genes have lost or gained imprinting, often associated with stably inherited epigenetic and genetic variation, suggesting a role in rice diversification. Our results highlight the role of transposable elements and epigenetic variation in shaping heritable changes in gene expression during rice evolution.
Beyond ‘fake news’?
Authors: Wright Scott
Published: July 2021

This article longitudinally analyses how Australian politicians engage with, and attack, journalists and the media more
generally on Twitter from 2011–2018. The article finds that attacks on journalists have increased significantly since 2016 when Trump came
to power, but this is largely the preserve of populist and far-right politicians. These politicians rarely call the media fake, instead
alleging bias or questioning the veracity or standards of reporting and production. Many politicians have a functional relationship with the
media, rarely criticising the media. Attacks are largely focused on the national public service broadcaster, the ABC, with limited attacks
on commercial media.
For family, for friends, for (true) love
Authors: Pak Vincent , Hiramoto Mie
Published: July 2021

We examine promotional materials produced by two organisations in Singapore, TrueLove.Is and Pink Dot, to investigate how
these two groups employ discourses of love to support their opposing views regarding the reconcilability of Christianity and same-sex desire.
TrueLove.Is is a Christian ministry that encourages LGB Christian Singaporeans to “come out, come home”, while Pink Dot is Singapore’s
largest and foremost LGBTQ movement. We identify similarities and differences in their persuasive discourse strategies regarding ideas of
love as discussed by lesbian Christian pastors. Although they position the idea of love similarly, their agendas are completely polarised.
TrueLove.Is takes the position that non-heteronormative activity is ungodly and sinful, while Pink Dot offers a reconciliation between Christianity
and same-sex desire. We employ Peterson’s (2016) approach to homophobic discourse analysis based on
Systemic Functional Linguistics and a comparative discourse analysis to investigate the ideologies that inform the two organisations’
materials about the treatment of LGBTQ Singaporeans.
A Small German Business Hotel on the Cutting Edge of Sustainability
Authors: Andre Julien , Duval Justine , Jeannon Marine , Yang Mo , Pi Marta Valls I
Published: July 2021

Creativhotel Luise, a business hotel of 93 rooms in the small town of Erlangen, Germany, operates on the principle that we are all responsible for the protection of the environment. The hotel puts this into practice through the concept of ‘creativity–sustainability’: creativity is used as a means of ensuring sustainability, whether in terms of economic viability, environmental responsibility, or social well-being.

Information

This case study is based on interviews with Ben Förtsch, owner & Managing Director of Creativhotel Luise. If a source is not provided for any data below, it will be from the information provided by Ben.

© CAB International 2021
Positioning public procurement as a procedural tool for innovation: an empirical study
Authors: Demircioglu Mehmet Akif , Vivona Roberto
Published: July 2021

Procurement has received scholarly attention as a valuable policy tool to reach desired outcomes in society, such as innovation. While interest has grown in analyzing the impact of the ‘substantive’ function of procurement (purchasing of goods and services), procurement is much more than purchases, and most public buyers’ activities are ‘procedural’, as they are aimed at improving the many internal stages of the procurement process. This study explains how procurement can be both a substantive and procedural tool, particularly in terms of innovation. Using the 2010 Innobarometer dataset that consist of 4,063 public organizations from 29 European countries, this study answers how public procurement, as a procedural policy tool, affects the implementation of public sector innovations. We find that procurement activities are positively related to innovation within public organizations. In particular, procurement as R&D for new technologies and services has an important and meaningful effect. We discuss implications for policy tools and public sector innovation literature, and we suggest that policy makers make use of more procedural tools such as procurement to increase innovation within public organizations.
Thermal axions with multi-eV masses are possible in low-reheating scenarios
Authors: Carenza Pierluca , Lattanzi Massimiliano , Mirizzi Alessandro , Forastieri Francesco
Published: July 2021

We revise cosmological mass bounds on hadronic axions in low-reheating cosmological scenarios, with a reheating temperature T
RH ≤ 100 MeV, in light of the latest cosmological observations. In this situation, the neutrino decoupling would be unaffected, while the thermal axion relic abundance is suppressed. Moreover, axions are colder in low-reheating temperature scenarios, so that bounds on their abundance are possibly loosened. As a consequence of these two facts, cosmological mass limits on axions are relaxed.
Using state-of-the-art cosmological data and characterizing axion-pion interactions at the leading order in chiral perturbation theory, we find in the standard case an axion mass bound m
a < 0.26 eV. However, axions with masses m
a ≃ 1 eV, or heavier, would be allowed for reheating temperatures T
RH ≲ 80 MeV. Multi-eV axions would be outside the mass sensitivity of current and planned solar axion helioscopes and would demand new experimental approaches to be detected.
Lost in Space? Relativistic Interstellar Navigation using an Astrometric Star Catalog
Authors: Bailer-Jones Coryn A. L.
Published: July 2021

The exploration of interstellar space will require autonomous navigation systems that do not rely on tracking from the Earth. Here I develop a method to determine the 3D position and 3D velocity of a spacecraft in deep space using a star catalog. As a spacecraft moves away from the Sun, the observed positions and velocities of the stars will change relative to those in a Earth-based catalog due to parallax and aberration. By measuring just the angular distances between pairs of stars, and comparing these to the catalog, we can infer the coordinates of the spacecraft via an iterative forward-modeling process. I perform simulations with existing star catalogs to demonstrate the method and to compute its performance. Using the 20 nearest stars and a modest angular distance measurement accuracy of 1″, the position and velocity of a spacecraft light years from the Sun moving at relativistic speeds can be determined to within 3

au

and 2

km

s

−
1

respectively. These accuracies improve linearly with the measurement accuracy, e.g., with angles measured to 1

mas

the navigation accuracy is 1000 times better. Performance can also be improved using more stars, or by including onboard measurements of the stars’ radial velocities, as these too are affected by the spacecraft’s position and motion.
An end-to-end heterogeneous graph attention network for Mycobacterium tuberculosis drug-resistance prediction
Authors: Yang Yang , Walker Timothy M , Kouchaki Samaneh , Wang Chenyang , Peto Timothy E A , Crook Derrick W ,   CRYPTIC Consortium, Clifton David A
Published: July 2021

Antimicrobial resistance (AMR) poses a threat to global public health. To mitigate the impacts of AMR, it is important to identify the molecular mechanisms of AMR and thereby determine optimal therapy as early as possible. Conventional machine learning-based drug-resistance analyses assume genetic variations to be homogeneous, thus not distinguishing between coding and intergenic sequences. In this study, we represent genetic data from Mycobacterium tuberculosis as a graph, and then adopt a deep graph learning method—heterogeneous graph attention network (‘HGAT–AMR’)—to predict anti-tuberculosis (TB) drug resistance. The HGAT–AMR model is able to accommodate incomplete phenotypic profiles, as well as provide ‘attention scores’ of genes and single nucleotide polymorphisms (SNPs) both at a population level and for individual samples. These scores encode the inputs, which the model is ‘paying attention to’ in making its drug resistance predictions. The results show that the proposed model generated the best area under the receiver operating characteristic (AUROC) for isoniazid and rifampicin (98.53 and 99.10%), the best sensitivity for three first-line drugs (94.91% for isoniazid, 96.60% for ethambutol and 90.63% for pyrazinamide), and maintained performance when the data were associated with incomplete phenotypes (i.e. for those isolates for which phenotypic data for some drugs were missing). We also demonstrate that the model successfully identifies genes and SNPs associated with drug resistance, mitigating the impact of resistance profile while considering particular drug resistance, which is consistent with domain knowledge.
Natriuretic peptide receptor B maintains heart rate and sinoatrial node function via cyclic GMP-mediated signalling
Authors: Dorey Tristan W , Mackasey Martin , Jansen Hailey J , McRae Megan D , Bohne Loryn J , Liu Yingjie , Belke Darrell D , Atkinson Logan , Rose Robert A
Published: July 2021

Aims

Heart rate (HR) is a critical indicator of cardiac performance that is determined by sinoatrial node (SAN) function and regulation. Natriuretic peptides, including C-type NP (CNP), have been shown to modulate ion channel function in the SAN when applied exogenously. CNP is the only NP that acts as a ligand for natriuretic peptide receptor-B (NPR-B). Despite these properties, the ability of CNP and NPR-B to regulate HR and intrinsic SAN automaticity in vivo, and the mechanisms by which it does so, are incompletely understood. Thus, the objective of this study was to determine the role of NPR-B signalling in regulating HR and SAN function.

Methods and results

We have used NPR-B deficient mice (NPR-B+/−) to study HR regulation and SAN function using telemetry in conscious mice, intracardiac electrophysiology in anaesthetized mice, high-resolution optical mapping in isolated SAN preparations, patch-clamping in isolated SAN myocytes, and molecular biology in isolated SAN tissue. These studies demonstrate that NPR-B+/− mice exhibit slow HR, increased corrected SAN recovery time, and slowed SAN conduction. Spontaneous AP firing frequency in isolated SAN myocytes was impaired in NPR-B+/− mice due to reductions in the hyperpolarization activated current (If) and L-type Ca2+ current (ICa,L). If and ICa,L were reduced due to lower cGMP levels and increased hydrolysis of cAMP by phosphodiesterase 3 (PDE3) in the SAN. Inhibiting PDE3 or restoring cGMP signalling via application of 8-Br-cGMP abolished the reductions in cAMP, AP firing, If, and ICa,L, and normalized SAN conduction, in the SAN in NPR-B+/− mice. NPR-B+/− mice did not exhibit changes in SAN fibrosis and showed no evidence of cardiac hypertrophy or changes in ventricular function.

Conclusions

NPR-B plays an essential physiological role in maintaining normal HR and SAN function by modulating ion channel function in SAN myocytes via a cGMP/PDE3/cAMP signalling mechanism.
Raphael’s ‘imperfect’ viol: a question of perspective
Authors: Hirsch Thilo , Haiduk Marina , Sayim Bilge
Published: July 2021

‘La viole parfaite’ is an article by Toon Moonen published in 1993, in which he describes his method of reconstructing an early viol on the basis of the instrument’s depiction in Raphael’s Saint Cecilia (c.1515–18). To date, the argument for using an iconographic source as a model for a Renaissance viol remains the same: all extant larger bowed stringed instruments dated to before the last quarter of the 16th century have been either so significantly modified that their original state is unrecognizable, or they are obvious counterfeits. This article examines Moonen’s reconstruction method in an interdisciplinary case study. Based on infrared reflectograms, for example, it was possible to show that the viol lying on the ground in Saint Cecilia was not subsequently altered. The reconstruction of the viol’s outline using 3d graphics yields completely new results, and perceptual psychology allows an analysis of the ‘reality effects’ possibly intended by the painter. In addition, this research also enables the examination of the general methodological requirements for reconstructing musical instruments from iconographic sources.
Long-term night shift work is associated with the risk of atrial fibrillation and coronary heart disease
Authors: Wang Ningjian , Sun Ying , Zhang Haojie , Wang Bin , Chen Chi , Wang Yuying , Chen Jie , Tan Xiao , Zhang Jihui , Xia Fangzhen , Qi Lu , Lu Yingli
Published: July 2021

Aims

The aim of this study was to test whether current and past night shift work was associated with incident atrial fibrillation (AF) and whether this association was modified by genetic vulnerability. Its associations with coronary heart disease (CHD), stroke, and heart failure (HF) were measured as a secondary aim.

Methods and results

This cohort study included 283 657 participants in paid employment or self-employed without AF and 276 009 participants free of CHD, stroke, and HF at baseline in the UK Biobank. Current and lifetime night shift work information was obtained. Cox proportional hazard models were used. Weighted genetic risk score for AF was calculated. During a median follow-up of 10.4 years, 5777 incident AF cases were documented. From ‘day workers’, ‘shift but never/rarely night shifts’, and ‘some night shifts’ to ‘usual/permanent night shifts’, there was a significant increasing trend in the risk of incident AF (P for trend 0.013). Usual or permanent night shifts were associated with the highest risk [hazard ratio (HR) 1.16, 95% confidence interval (CI) 1.02–1.32]. Considering a person’s lifetime work schedule and compared with shift workers never working nights, participants with a duration over 10 years and an average 3–8 nights/month frequency of night shift work exposure possessed higher AF risk (HR 1.18, 95% CI 0.99–1.40 and HR 1.22, 95% CI 1.02–1.45, respectively). These associations between current and lifetime night shifts and AF were not modified by genetic predisposition to AF. Usual/permanent current night shifts, ≥10 years and 3–8 nights/month of lifetime night shifts were significantly associated with a higher risk of incident CHD (HR 1.22, 95% CI 1.11–1.35, HR 1.37, 95% CI 1.20–1.58 and HR 1.35, 95% CI 1.18–1.55, respectively). These associations in stroke and HF were not significant.

Conclusion

Both current and lifetime night shift exposures were associated with increased AF risk, regardless of genetic AF risk. Night shift exposure also increased the risk of CHD but not stroke or HF. Whether decreasing night shift work frequency and duration might represent another avenue to improve heart health during working life and beyond warrants further study.
Prestack seismic inversion using a Rytov-WKBJ approximation
Authors: Huang Guangtan , Chen Xiaohong , Li Jingye , Luo Cong , Wang Hang , Chen Yangkang
Published: July 2021

Approaches to seismic modeling using integral methods, notably Born-WKBJ (Wentzel-Kramers-Brillouin-Jeffreys), have seen an increase in applications in geophysical prospecting and near-surface exploration. Moreover, due to its linearity characteristic, which can fast and efficiently simulate full-waveform information, the Born-WKBJ based method performs well in seismic inversion. However, the Born approximation is the linearized wavefield simulation by Taylor expansion of the wavefield and omitting the high-order term, which cannot simulate the wavefiled accurately, including the amplitude, phase, and waveform information. For the seismic inversion, especially the amplitude variation with angle/offset (AVA/AVO) inversion, the amplitude is the most important element for estimating the parameters. In this paper, a Rytov-WKBJ approximation-based method, which can simulate the seismic amplitude information more accurately, is introduced to prestack seismic inversion. Besides, in order to improve the resolution of the inversion results, the ℓ1 − 2-norm regularized basis pursuit inversion (BPI) is introduced to the inversion algorithm. Then, we demonstrate the superiority of the proposed method with the zero-offset and angle-dependent seismic data simulation. The model tests show that the proposed method performs better than the conventional method significantly both on amplitude and phase of the seismic data. Finally, the inversion tests of synthetic and field seismic data indicate that the proposed method can obtain more accurate results with a higher resolution.
Germline ERBB3 mutation in familial non-small-cell lung carcinoma: expanding ErbB’s role in oncogenesis
Authors: McInerney-Leo Aideen M , Chew Hui Yi , Inglis Po-Ling , Leo Paul J , Joseph Shannon R , Cooper Caroline L , Okano Satomi , Hassall Tim , Anderson Lisa K , Bowman Rayleen V , Gattas Michael , Harris Jessica E , Marshall Mhairi S , Shaw Janet G , Wheeler Lawrie , Yang Ian A , Brown Matthew A , Fong Kwun M , Simpson Fiona , Duncan Emma L
Published: July 2021

Lung cancer is the commonest cause of cancer deaths worldwide. Although strongly associated with smoking, predisposition to lung cancer is also heritable, with multiple common risk variants identified. Rarely, dominantly inherited non-small-cell lung cancer (NSCLC) has been reported due to somatic mutations in EGFR/ErbB1 and ERBB2. Germline exome sequencing was performed in a multi-generation family with autosomal dominant NSCLC, including an affected child. Tumour samples were also sequenced. Full-length wild-type (wtErbB3) and mutant ERBB3 (mutErbB3) constructs were transfected into HeLa cells. Protein expression, stability, and subcellular localization were assessed, and cellular proliferation, pAkt/Akt and pERK levels determined. A novel germline variant in ERBB3 (c.1946 T > G: p.Iso649Arg), coding for receptor tyrosine-protein kinase erbB-3 (ErbB3), was identified, with appropriate segregation. There was no loss-of-heterozygosity in tumour samples. Both wtErbB3 and mutErbB3 were stably expressed. MutErbB3-transfected cells demonstrated an increased ratio of the 80 kDa form (which enhances proliferation) compared with the full-length (180 kDa) form. MutErbB3 and wtErbB3 had similar punctate cytoplasmic localization pre- and post-epidermal growth factor stimulation; however, epidermal growth factor receptor (EGFR) levels decreased faster post-stimulation in mutErbB3-transfected cells, suggesting more rapid processing of the mutErbB3/EGFR heterodimer. Cellular proliferation was increased in mutErbB3-transfected cells compared with wtErbB3 transfection. MutErbB3-transfected cells also showed decreased pAkt/tAkt ratios and increased pERK/tERK 30 min post-stimulation compared with wtErbB3 transfection, demonstrating altered signalling pathway activation. Cumulatively, these results support this mutation as tumorogenic. This is the first reported family with a germline ERBB3 mutation causing heritable NSCLC, furthering understanding of the ErbB family pathway in oncogenesis.
Immortalized striatal precursor neurons from Huntington’s disease patient-derived iPS cells as a platform for target identification and screening for experimental therapeutics
Authors: Akimov Sergey S , Jiang Mali , Kedaigle Amanda J , Arbez Nicolas , Marque Leonard O , Eddings Chelsy R , Ranum Paul T , Whelan Emma , Tang Anthony , Wang Ronald , DeVine Lauren R , Talbot Conover C , Cole Robert N , Ratovitski Tamara , Davidson Beverly L , Fraenkel Ernest , Ross Christopher A
Published: July 2021

We have previously established induced pluripotent stem cell (iPSC) models of Huntington’s disease (HD), demonstrating CAG-repeat-expansion-dependent cell biological changes and toxicity. However, the current differentiation protocols are cumbersome and time consuming, making preparation of large quantities of cells for biochemical or screening assays difficult. Here, we report the generation of immortalized striatal precursor neurons (ISPNs) with normal (33) and expanded (180) CAG repeats from HD iPSCs, differentiated to a phenotype resembling medium spiny neurons (MSN), as a proof of principle for a more tractable patient-derived cell model. For immortalization, we used co-expression of the enzymatic component of telomerase hTERT and conditional expression of c-Myc. ISPNs can be propagated as stable adherent cell lines, and rapidly differentiated into highly homogeneous MSN-like cultures within 2 weeks, as demonstrated by immunocytochemical criteria. Differentiated ISPNs recapitulate major HD-related phenotypes of the parental iPSC model, including brain-derived neurotrophic factor (BDNF)-withdrawal-induced cell death that can be rescued by small molecules previously validated in the parental iPSC model. Proteome and RNA-seq analyses demonstrate separation of HD versus control samples by principal component analysis. We identified several networks, pathways, and upstream regulators, also found altered in HD iPSCs, other HD models, and HD patient samples. HD ISPN lines may be useful for studying HD-related cellular pathogenesis, and for use as a platform for HD target identification and screening experimental therapeutics. The described approach for generation of ISPNs from differentiated patient-derived iPSCs could be applied to a larger allelic series of HD cell lines, and to comparable modeling of other genetic disorders.
Geographically Weighted Regression Modeling of Spatial Clustering and Determinants of Focal Typhoid Fever Incidence
Authors: Mohan Venkata Raghava , Srinivasan Manikandan , Sinha Bireshwar , Shrivastava Ankita , Kanungo Suman , Natarajan Sindhu Kulandaipalayam , Ramanujam Karthikeyan , Ganesan Santhosh Kumar , Karthikeyan Arun S , Kumar Jaganathan Senthil , Gunasekaran Annai , Arya Alok , Bavdekar Ashish , Rongsen-Chandola Temsunaro , Dutta Shanta , John Jacob , Kang Gagandeep
Published: July 2021

Background

Typhoid is known to be heterogenous in time and space, with documented spatiotemporal clustering and hotspots associated with environmental factors. This analysis evaluated spatial clustering of typhoid and modeled incidence rates of typhoid from active surveillance at 4 sites with child cohorts in India.

Methods

Among approximately 24 000 children aged 0.5–15 years followed for 2 years, typhoid was confirmed by blood culture in all children with fever >3 days. Local hotspots for incident typhoid cases were assessed using SaTScan spatial cluster detection. Incidence of typhoid was modeled with sociodemographic and water, sanitation, and hygiene–related factors in smaller grids using nonspatial and spatial regression analyses.

Results

Hotspot households for typhoid were identified at Vellore and Kolkata. There were 4 significant SaTScan clusters (P < .05) for typhoid in Vellore. Mean incidence of typhoid was 0.004 per child-year with the highest incidence (0.526 per child-year) in Kolkata. Unsafe water and poor sanitation were positively associated with typhoid in Kolkata and Delhi, whereas drinking untreated water was significantly associated in Vellore (P = .0342) and Delhi (P = .0188).

Conclusions

Despite decades of efforts to improve water and sanitation by the Indian government, environmental factors continue to influence the incidence of typhoid. Hence, administration of the conjugate vaccine may be essential even as efforts to improve water and sanitation continue.
Adjuvant and neoadjuvant chemotherapy for osteosarcoma: JCOG Bone and Soft Tissue Tumor Study Group
Authors: Hiraga Hiroaki , Ozaki Toshifumi
Published: July 2021

The usefulness of adjuvant chemotherapy for high-grade osteosarcoma was established by two randomized, controlled trials conducted in the 1980s, which used six drugs, doxorubicin, cisplatin, high-dose methotrexate, bleomycin, cyclophosphamide and actinomycin D. Since then, development has been promoted in the direction of introducing preoperative chemotherapy, changing post-operative adjuvant chemotherapy according to histological effects, adding ifosfamide as a key drug and strengthening adjuvant chemotherapy. No clinical trials, however, have shown the effectiveness of study treatment, and the improvement of treatment results during that time has been slight, although the JCOG0905 study is now going to verify the effectiveness of introducing ifosfamide for patients who experienced limited preoperative therapeutic effects. We are desperately looking for a breakthrough.
Mendelssohn on the Edge: Memory, Agency, and National Belonging in Weimar Germany
Authors: Steer Martina
Published: July 2021

In times of great political unrest and disorientation, societies generally invent and reinvent myths. As unrest and disorientation were among the most striking characteristics of the Weimar era, it is not surprising that the bicentenary celebrations of Moses Mendelssohn’s birth, held in 1929, constituted the peak of the Enlightenment philosopher’s popularity as a German-Jewish patron saint. This article argues that the commemoration of Mendelssohn on the eve of catastrophe, four years before the Weimar Republic’s collapse, serves as a particularly precise indicator of ambivalent German-Jewish agency at the time, due to its political, social, and cultural implications. Whereas the bicentenary celebrations—featuring the Republic’s most prominent representatives, state-of-the-art exhibitions, cultural events in prestigious locations, and extensive media coverage—attest to the considerable leeway German Jewry had in shaping social reality, the continuing absence of Mendelssohn in the canon of German poets and thinkers illustrates the limits of German-Jewish agency in the cultural imaginary of the German nation.
The BACCO simulation project: exploiting the full power of large-scale structure for cosmology
Authors: Angulo Raul E , Zennaro Matteo , Contreras Sergio , Aricò Giovanni , Pellejero-Ibañez Marcos , Stücker Jens
Published: July 2021

We present the BACCO project, a simulation framework specially designed to provide highly-accurate predictions for the distribution of mass, galaxies, and gas as a function of cosmological parameters. In this paper, we describe our main suite of gravity-only simulations ($L\sim 2\,$ Gpc and 43203 particles) and present various validation tests. Using a cosmology-rescaling technique, we predict the non-linear mass power spectrum over the redshift range 0 < z < 1.5 and over scales $10^{-2} \lt k/(\, h\, {\rm Mpc}^{-1}) \lt 5$ for 800 points in an eight-dimensional cosmological parameter space. For an efficient interpolation of the results, we build an emulator and compare its predictions against several widely-used methods. Over the whole range of scales considered, we expect our predictions to be accurate at the $2{{\ \rm per\ cent}}$ level for parameters in the minimal Lambda cold dark matter model and to $3{{\ \rm per\ cent}}$ when extended to dynamical dark energy and massive neutrinos. We make our emulator publicly available under http://www.dipc.org/bacco
GRB jet structure and the jet break
Authors: Lamb Gavin P , Kann D Alexander , Fernández Joseph John , Mandel Ilya , Levan Andrew J , Tanvir Nial R
Published: July 2021

We investigate the shape of the jet break in within-beam gamma-ray burst (GRB) optical afterglows for various lateral jet structure profiles. We consider cases with and without lateral spreading and a range of inclinations within the jet core half-opening angle, θc. We fit model and observed afterglow light curves with a smoothly-broken power-law function with a free-parameter κ that describes the sharpness of the break. We find that the jet break is sharper (κ is greater) when lateral spreading is included than in the absence of lateral spreading. For profiles with a sharp-edged core, the sharpness parameter has a broad range of 0.1 ≲ κ ≲ 4.6, whereas profiles with a smooth-edged core have a narrower range of 0.1 ≲ κ ≲ 2.2 when models both with and without lateral spreading are included. For sharp-edged jets, the jet break sharpness depends strongly on the inclination of the system within θc, whereas for smooth-edged jets, κ is more strongly dependent on the size of θc. Using a sample of 20 GRBs, we find 9 candidate smooth-edged jet structures and 8 candidate sharp-edged jet structures, while the remaining 3 are consistent with either. The shape of the jet break, as measured by the sharpness parameter κ, can be used as an initial check for the presence of lateral structure in within-beam GRBs where the afterglow is well-sampled at and around the jet-break time.
SMILE: Search for MIlli-LEnses
Authors: Casadio C , Blinov D , Readhead A C S , Browne I W A , Wilkinson P N , Hovatta T , Mandarakas N , Pavlidou V , Tassis K , Vedantham H K , Zensus J A , Diamantopoulos V , Dolapsaki K E , Gkimisi K , Kalaitzidakis G , Mastorakis M , Nikolaou K , Ntormousi E , Pelgrims V , Psarras K
Published: July 2021

Dark matter (DM) haloes with masses below ∼108 M⊙, which would help to discriminate between DM models, may be detected through their gravitational effect on distant sources. The same applies to primordial black holes, considered as an alternative scenario to DM particle models. However, there is still no evidence for the existence of such objects. With the aim of finding compact objects in the mass range of ∼106–109 M⊙, we search for strong gravitational lenses on milliarcsec scales (<150 mas). For our search, we used the Astrogeo very long baseline interferometry (VLBI) fits image data base – the largest publicly available data base, containing multifrequency VLBI data of 13 828 individual sources. We used the citizen science approach to visually inspect all sources in all available frequencies in search for images with multiple compact components on mas scales. At the final stage, sources were excluded based on the surface brightness preservation criterion. We obtained a sample of 40 sources that passed all steps and therefore are judged to be mas lens candidates. These sources are currently followed up with ongoing European VLBI network observations at 5 and 22 GHz. Based on spectral index measurements, we suggest that two of our candidates have a higher probability to be associated with gravitational lenses.
Integration host factor bends and bridges DNA in a multiplicity of binding modes with varying specificity
Authors: Yoshua Samuel B , Watson George D , Howard Jamieson A L , Velasco-Berrelleza Victor , Leake Mark C , Noy Agnes
Published: July 2021

Nucleoid-associated proteins (NAPs) are crucial in organizing prokaryotic DNA and regulating genes. Vital to these activities are complex nucleoprotein structures, however, how these form remains unclear. Integration host factor (IHF) is an Escherichia coli NAP that creates very sharp bends in DNA at sequences relevant to several functions including transcription and recombination, and is also responsible for general DNA compaction when bound non-specifically. We show that IHF–DNA structural multimodality is more elaborate than previously thought, and provide insights into how this drives mechanical switching towards strongly bent DNA. Using single-molecule atomic force microscopy and atomic molecular dynamics simulations we find three binding modes in roughly equal proportions: ‘associated’ (73° of DNA bend), ‘half-wrapped’ (107°) and ‘fully-wrapped’ (147°), only the latter occurring with sequence specificity. We show IHF bridges two DNA double helices through non-specific recognition that gives IHF a stoichiometry greater than one and enables DNA mesh assembly. We observe that IHF-DNA structural multiplicity is driven through non-specific electrostatic interactions that we anticipate to be a general NAP feature for physical organization of chromosomes.