bluuebunny/crossref_metadata_2025 huggingface dataset:
Electron transport with the McKelvey–Shockley flux method: The effect of electric field and electron–phonon scattering
Authors: Zhu Qinxin , Maassen Jesse
Published: August 2022

The McKelvey–Shockley (McK–S) flux method is a semi-classical transport theory that captures ballistic and non-equilibrium effects and can treat carrier flow from the nano-scale to the macro-scale. This work introduces a revised formulation of the McK–S flux equations for electron transport, in order to resolve the energy dependence of the fluxes, capture the effect of electric field, and include acoustic/optical phonon scattering. This updated McK–S formalism is validated by simulating electron transport across a finite-length semiconductor under the influence of a constant electric field under varying conditions, from ballistic to diffusive and from near-equilibrium to non-equilibrium, and benchmarked against solutions of the Boltzmann transport equation (BTE). The McK–S results display good agreement with those of the BTE, including the directed fluxes and heating profiles, with the electron density showing larger differences when far from equilibrium. Compared to other more rigorous techniques, the McK–S flux method is physically intuitive and computationally efficient and, thus, well suited to treat systems that are complex and/or span multiple length scales.
Perspective on radiation effects in nanoscale metal–oxide–semiconductor devices
Authors: Fleetwood D. M.
Published: August 2022

This article provides a brief overview and perspective on the radiation response of nanoscale metal–oxide–semiconductor (MOS) devices. MOS total-ionizing-dose (TID) response is affected strongly by size scaling and the migration from planar to three-dimensional architectures. Radiation-induced charge trapping in isolation oxides and/or charge transport from surrounding materials are critical to the TID response of nanoscale MOS devices. As transistor dimensions and operating voltages have decreased, single-event effects due to cosmic rays and high-energy protons in space and neutrons in terrestrial environments have become increasingly significant to the radiation response of MOS devices. However, nanoscale MOS transistors are essentially immune to ion-induced gate rupture at normal operating voltages. Single-particle interactions will become even more important for future, ultimately scaled MOS devices used in classical and quantum computing applications.
Effects of He-ion bombardment on the ferroelectric and dielectric properties of BaHf0.17Ti0.83O3 films
Authors: Lu Rui , Hu Guangliang , Zhao Wanli , Liu Tongyu , Fan Jiangqi , Ma Chunrui , Lu Lu , Liu Linyue , Liu Ming
Published: August 2022

Focused helium ion bombardment provides an effective means to modify the properties of ferroelectric materials. This work systematically investigates the effect of helium ion bombardment on the structural, ferroelectric, and dielectric properties of relaxor BaHf0.17Ti0.83O3 thin films at different bombardment doses in the range of 1 × 1012 to 7 × 1015 ions/cm2. The films show more defects and slightly expanded out-of-plane lattice parameters with an increase in dose. Despite helium ion bombardment introducing more defects and structural disorder in the system, the bombardment-induced dipole polarization leads to enhanced ferroelectricity. Our findings highlight energetic helium ion bombardment as an effective way to enhance the ferroelectricity of relaxor materials.
Effect of electrode geometry on the flow structure induced by plasma actuators
Authors: Sun Zhikun , Shi Zhiwei , Li Zheng , Geng Xi , Yin Zhenquan
Published: August 2022

Pulsed surface arc discharge (PSAD) is one of the essential techniques in flow control. In this paper, the effects of electrode configuration on heat transfer characteristics of PSAD and disturbance characteristics of PSAD on the flow field were investigated by thermal imaging technology and high-speed photography technology. By defining the curvature of curve (COC) of the electrode, we investigated the physical mechanism of the electrode configuration, affecting the PSAD disturbed flow field. The results show that the COC has the optimal solution COCopt. When COC ≤ COCopt, the smaller the COC, the more concentrated the PSAD disturbances to the flow field. When COC > COCopt, the electrode configuration will have an end point effect, resulting in a deviation between the theoretical COC and the real COC. The larger the COC, the stronger the end point effect, and the more concentrated the PSAD disturbances to the flow field. The COC affects the disturbance degree of PSAD to the flow field by distorting the electric field intensity distribution. The change in the electric field intensity causes the fluctuation frequency of the flow field to be inconsistent with the discharge frequency of the PSAD. The stronger the distortion degree of the electric field intensity, the stronger the high-frequency characteristics of the fluctuating frequency of the flow field, and the stronger the high-frequency characteristics of the flow mode of the flow field. In addition, we obtained the value range of COCopt within 0.5–0.7 through theoretical derivation and established a mathematical model of electrode structure's effect on the flow field's flow structure.
Enhancing search efficiency through diffusive echo
Authors: Antoine Charles , Talbot Julian
Published: August 2022

Despite having been studied for decades, first passage processes remain an active area of research. In this article, we examine a particle diffusing in an annulus with an inner absorbing boundary and an outer reflective boundary. We obtain analytic expressions for the joint distribution of the hitting time and the hitting angle in two and three dimensions. For certain configurations, we observe a “diffusive echo,” i.e., two well-defined maxima in the first passage time distribution to a targeted position on the absorbing boundary. This effect, which results from the interplay between the starting location and the environmental constraints, may help to significantly increase the efficiency of the random search by generating a high, sustained flux to the targeted position over a short period. Finally, we examine the corresponding one-dimensional system for which there is no well-defined echo. In a confined system, the flux integrated over all target positions always displays a shoulder. This does not, however, guarantee the presence of an echo in the joint distribution.
TGF-β regulates the stem-like state of PD-1+ TCF-1+ virus-specific CD8 T cells during chronic infection
Authors: Hu Yinghong , Hudson William H. , Kissick Haydn T. , Medina Christopher B. , Baptista Antonio P. , Ma Chaoyu , Liao Wei , Germain Ronald N. , Turley Shannon J. , Zhang Nu , Ahmed Rafi
Published: August 2022

Recent studies have defined a novel population of PD-1+ TCF-1+ stem-like CD8 T cells in chronic infections and cancer. These quiescent cells reside in lymphoid tissues, are critical for maintaining the CD8 T cell response under conditions of persistent antigen, and provide the proliferative burst after PD-1 blockade. Here we examined the role of TGF-β in regulating the differentiation of virus-specific CD8 T cells during chronic LCMV infection of mice. We found that TGF-β signaling was not essential for the generation of the stem-like CD8 T cells but was critical for maintaining the stem-like state and quiescence of these cells. TGF-β regulated the unique transcriptional program of the stem-like subset, including upregulation of inhibitory receptors specifically expressed on these cells. TGF-β also promoted the terminal differentiation of exhausted CD8 T cells by suppressing the effector-associated program. Together, the absence of TGF-β signaling resulted in significantly increased accumulation of effector-like CD8 T cells. These findings have implications for immunotherapies in general and especially for T cell therapy against chronic infections and cancer.
HER2 drives lung fibrosis by activating a metastatic cancer signature in invasive lung fibroblasts
Authors: Liu Xue , Geng Yan , Liang Jiurong , Coelho Ana Lucia , Yao Changfu , Deng Nan , Wang Yizhou , Dai Kristy , Huang Guanling , Xie Ting , Liu Ningshan , Rowan Simon C. , Taghavifar Forough , Kulur Vrishika , Liu Zhenqiu , Stripp Barry R. , Hogaboam Cory M. , Jiang Dianhua , Noble Paul W.
Published: August 2022

Progressive tissue fibrosis, including idiopathic pulmonary fibrosis (IPF), is characterized by excessive recruitment of fibroblasts to sites of tissue injury and unremitting extracellular matrix deposition associated with severe morbidity and mortality. However, the molecular mechanisms that control progressive IPF have yet to be fully determined. Previous studies suggested that invasive fibroblasts drive disease progression in IPF. Here, we report profiling of invasive and noninvasive fibroblasts from IPF patients and healthy donors. Pathway analysis revealed that the activated signatures of the invasive fibroblasts, the top of which was ERBB2 (HER2), showed great similarities to those of metastatic lung adenocarcinoma cancer cells. Activation of HER2 in normal lung fibroblasts led to a more invasive genetic program and worsened fibroblast invasion and lung fibrosis, while antagonizing HER2 signaling blunted fibroblast invasion and ameliorated lung fibrosis. These findings suggest that HER2 signaling may be a key driver of fibroblast invasion and serve as an attractive target for therapeutic intervention in IPF.
Mutations in proteins involved in E-C coupling and SOCE and congenital myopathies
Authors: Rossi Daniela , Catallo Maria Rosaria , Pierantozzi Enrico , Sorrentino Vincenzo
Published: August 2022

In skeletal muscle, Ca2+ necessary for muscle contraction is stored and released from the sarcoplasmic reticulum (SR), a specialized form of endoplasmic reticulum through the mechanism known as excitation–contraction (E-C) coupling. Following activation of skeletal muscle contraction by the E-C coupling mechanism, replenishment of intracellular stores requires reuptake of cytosolic Ca2+ into the SR by the activity of SR Ca2+-ATPases, but also Ca2+ entry from the extracellular space, through a mechanism called store-operated calcium entry (SOCE). The fine orchestration of these processes requires several proteins, including Ca2+ channels, Ca2+ sensors, and Ca2+ buffers, as well as the active involvement of mitochondria. Mutations in genes coding for proteins participating in E-C coupling and SOCE are causative of several myopathies characterized by a wide spectrum of clinical phenotypes, a variety of histological features, and alterations in intracellular Ca2+ balance. This review summarizes current knowledge on these myopathies and discusses available knowledge on the pathogenic mechanisms of disease.
Healing the cosmological constant problem during inflation through a unified quasi-quintessence matter field
Authors: D’Agostino Rocco , Luongo Orlando , Muccino Marco
Published: August 2022

We heal the cosmological constant problem by means of a cancellation mechanism that adopts a phase transition during which quantum fluctuations are eliminated. To this purpose, we propose that a generalized scalar (dark) matter field with a non-vanishing pressure term can remove the vacuum energy contribution, if its corresponding thermodynamics is written in terms of a quasi-quintessence representation. In such a picture, pressure differs from quintessence as it shows a zero kinetic contribution. Using this field, we investigate a metastable transition phase, in which the Universe naturally passes through an inflationary phase. To reach this target, we single out a double exponential potential, describing the metastable inflationary dynamics by considering suitable boundaries and thermodynamic conditions. We analyze stability investigating saddle, stable and unstable points and we thus predict a chaotic inflation that mimics the Starobinsky exponential potential. Consequently, the role of the proposed dark matter field is investigated throughout the overall Universe evolution. To do so, we provide a physical explanation on unifying the dark sector with inflation by healing the cosmological constant problem.
A dataset-free deep learning method for low-dose CT image reconstruction
Authors: Ding Qiaoqiao , Ji Hui , Quan Yuhui , Zhang Xiaoqun
Published: August 2022

Low-dose CT (LDCT) imaging attracted a considerable interest for the reduction of the object’s exposure to x-ray radiation. In recent years, supervised deep learning (DL) has been extensively studied for LDCT image reconstruction, which trains a network over a dataset containing many pairs of normal-dose and low-dose images. However, the challenge on collecting many such pairs in the clinical setup limits the application of supervised-learning-based methods for LDCT image reconstruction in practice. Aiming at addressing the challenges raised by the collection of a training dataset, this paper proposed an unsupervised DL method for LDCT image reconstruction, which does not require any external training data. The proposed method is built on a re-parametrization technique for Bayesian inference via a deep network with random weights, combined with additional total variational regularization. The experiments show that the proposed method noticeably outperforms existing dataset-free image reconstruction methods on the test data.
Fast inverse elastic scattering of multiple particles in three dimensions*
Authors: Lai Jun , Zhang Jinrui
Published: August 2022

Many applications require recovering the geometric information of multiple elastic particles based on the scattering information. In this paper, we consider the inverse time-harmonic elastic scattering of multiple rigid particles in three dimensions. We measure the far field information and apply the time reversal method to recover the unknown elastic particles. Two regimes are considered depending on the size and distance among particles. First, an asymptotic analysis for the imaging of small and distant particles is given based on the scattering property of a single particle, which can be used for selective focusing. Second, when particles are not small but well-separated, a fast algorithm, based on the combination of multiple scattering theory and fast multipole method, is proposed to efficiently simulate the forward multiple scattering problem and applied to the inverse elastic scattering. Numerical experiments demonstrate the proposed method can effectively recover the locations and shapes of multiple unknown particles.
Critical screening parameters of one-electron systems with screened Coulomb potentials: high Rydberg limit
Authors: Jiao Li Guang , Xu Lei , Zheng Ruo Yu , Liu Aihua , Zhang Yong Zhi , Montgomery H E , Ho Yew Kam
Published: August 2022

We develop an efficient numerical method to directly calculate the critical screening parameters for one-electron systems with Hulthén and Debye–Hückel screened Coulomb potentials (SCPs). Compared to indirect methods, which locate the critical screening parameters via searching the potential parameters with near-zero energy, the method developed in this work directly calculates the critical screening parameters as eigenvalues of a generalized eigenvalue problem. This feature allows us to simultaneously determine the critical parameters for bound states from low-lying excitation to high-lying Rydberg limit with high accuracy. The method is applied to SCPs to investigate the asymptotic behavior of critical screening parameters as the principal quantum number n approaches infinity. It has been shown that the critical screening parameters in Hulthén and Debye–Hückel potentials follow the 2n
−2 and 4n
−2/π asymptotic laws, respectively, and that the orbital angular momentum affects the higher-order coefficients linearly.
Ultrafast laser matter interactions: modeling approaches, challenges, and prospects
Authors: Miloshevsky Gennady
Published: August 2022

The irradiation of the target surface by an ultrafast femtosecond (fs) laser pulse produces the extreme non-equilibrium states of matter and subsequent phase transformations. Computational modeling and simulation is a very important tool for gaining insight into the physics processes that govern the laser–matter interactions, and, specifically, for quantitative understanding the laser light absorption, electron–ion energy exchange, spallation, melting, warm dense matter regime, vaporization, and expansion of plasma plume. High-fidelity predictive modeling of a variety of these multi-physics processes that take place at various time and length scales is extremely difficult, requiring the coupled multi-physics and multi-scale models. This topical review covers progress and advances in developing the modeling approaches and performing the state-of-the-art simulations of fs laser-pulse interactions with solids and plasmas. A complete kinetic description of a plasma based on the most accurate Vlasov–Maxwell set of equations is first presented and discussed in detail. After that an exact kinetic model that encompasses the microscopic motions of all the individual particles, their charge and current densities, generated electric and magnetic fields, and the effects of these fields on the motion of charged particles in a plasma is briefly reviewed. The methodology of kinetic particle-in-cell (PIC) approach that is well suitable for computational studies of the non-linear processes in laser–plasma interactions is then presented. The hydrodynamic models used for the description of plasmas under the assumption of a local thermodynamic equilibrium include the two-fluid and two-temperature model and its simplifications. The two-temperature model coupled with molecular dynamics (MD) method is finally discussed. Examples are illustrated from research areas such as applications of the fully kinetic, PIC, hydrodynamic, and MD models to studies of ultrafast laser–matter interactions. Challenges and prospects in the development of computational models and their applications to the modeling of ultrafast intense laser–solid and laser–plasma interactions are overviewed.
Effect of Ag nanoparticle size on triboelectric nanogenerator for mechanical energy harvesting
Authors: Zhang Ping , Li Peng-Fei , Zhang Hong-Hao , Deng Lu
Published: August 2022

Triboelectric nanogenerators (TENG) are generally utilized on the grounds that they can catch low-recurrence mechanical energy from various types of movement and convert it into electricity. It has been proved that the adulteration of conductive particles in the triboelectric layer can improve its output performance, but metal nanomaterials have different properties at different scales. In this paper, the triboelectric layer of TENG is a composite film made of silver nanoparticles (AgNPs) with different particle sizes (20 nm, 50 nm, 200 nm and 500 nm) that were dispersed and mixed with two-component liquid silica gel step by step. The open circuit voltage (Voc) and short circuit current (Isc) of the 20 nm component of the AgNPs-dispersed/two-component liquid silica gel TENG(At-TENG) are 102.8 V and 4.42 μA, which are higher than the result execution of the other components. Smaller size nanoparticles have more number of nanoparticles when the mass fraction is the same. AgNPs form micro-capacitance structures in the insulating polymer layer and enhance the dielectric properties of the composite films through an interfacial polarization mechanism. At-TENG can light up 53 commercial LEDs and power calculators or wristband electronic watches, proving its utility as a self-powered power source. An extensive experiment proves the advantage of small size using comparison and theoretical analysis and provides suggestions for the selection of TENG dopants.
Validating NEUTRO, a deterministic finite element neutron transport solver for fusion applications, with literature tests, experimental benchmarks and other neutronic codes
Authors: Goldberg E , Circuns i Duxans M , Ortega Gelabert O , Mantsinen M J , Soba A
Published: August 2022

Neutron reactions on fusion reactor materials are key phenomena to be understood to enable fusion as a feasible energy source for future reactors. We present significant improvements and validations of NEUTRO, a deterministic neutron transport code dedicated to solving the Boltzmann transport equation. The code is integrated as a module in the Alya system developed by the Barcelona Supercomputing Center and uses the discrete ordinates method over an angular portion, multigroup for energy discretization and the finite element method over unstructured meshes to treat special complex domains. Material anisotropy of the scattering medium is introduced into the scattering kernel using real base expressions for spherical harmonics. In order to build the total cross-section and the respective group matrix for the elastic cross-section, we use the NJOY code. We test the solver using different geometries and materials with varying levels of scattering properties. We compare our results on classic tests, benchmarks obtained from a Nuclear Energy Agency database and test cases using other neutron transport codes.
Thermal instabilities in micropinches under turbulent heating conditions
Authors: Oreshkin V I , Artyomov A P , Oreshkin E V
Published: August 2022

Anomalous thermal (AT) instabilities occurring in micropinches are analyzed based on the theory of small perturbations. Instabilities of this type develop in a high-temperature plasma under turbulent heating conditions in the presence of an anomalous resistance resulting from the scattering of electrons by lower hybrid drift oscillations. When turbulent heating occurs in the plasma of a micropinch, its resistivity increases with decreasing density; this may lead to the formation of plasma layers normal to the current flow (stratification). For the AT instability, a dispersion relation taking into account the effect of the plasma self-radiation has been derived, and the characteristic instability growth rates and wavelengths have been determined. A comparison of the development pattern has been performed between AT and sausage-type magnetohydrodynamic instabilities. It has been shown that for any pinch material, there is a threshold current below which AT instabilities prevail over magnetohydrodynamic instabilities. For the metals considered (aluminum, titanium, copper, molybdenum, and tungsten), the threshold currents are hundreds of kiloamperes. The threshold current increases with atomic number: for tungsten, it is approximately 3.5 times higher than for aluminum. The conclusions drawn from the analysis based on the linear small perturbation theory are compared with the results of experiments in which the parameters of ‘hot spots’ formed in X pinches were determined.
High-current-density Rutherford MgB2 cable sheathed by CuNi30 alloy
Authors: Kováč P , Kopera L , Berek D , Hain M , Melišek T , Hušek I , Kováč J , Búran M
Published: August 2022

A Rutherford-type MgB2 cable has been fabricated from 12 six-core strands prepared by an internal magnesium diffusion (IMD) process with a resistive CuNi30 outer sheath. The uniformity of individual strands of diameter 0.448 mm prior to and after additional densification by rolling was studied by x-ray micro-tomography. The engineering current densities of the cable samples were measured at 4.2 K and external magnetic fields between 4.0 T and 8.0 T and compared with available published data. The presented Rutherford cable has the highest engineering current density with J
e = 104 A cm2 measured in an external magnetic field of 5.73 T. The bending tolerance of the cable shows a critical diameter of 60 mm and less gradual critical current degradation in comparison to similar cables fabricated from single-core strands. The AC loss measurements of the present cable show lower coupling losses in comparison to monolithic multicore IMD conductors. The obtained results are promising for high-current-density and low-AC-loss MgB2 superconducting cables that are suitable especially for motors and generators.
Polarization-independent tunable terahertz slow light with electromagnetically induced transparency metasurface
Authors: Devi Koijam Monika , Jana Arun , Punjal Ajinkya , Acharyya Nityananda , Prabhu Shriganesh S , Roy Chowdhury Dibakar
Published: August 2022

Tunable slow light systems have gained much interests recently due to their efficient control of strong light–matter interactions as well as their huge potential for realizing tunable device applications. Here, a dynamically tunable polarization independent slow light system is experimentally demonstrated via electromagnetically induced transparency (EIT) in a terahertz (THz) metasurface constituted by plus and dimer-shaped resonators. Optical pump-power dependent THz transmissions through the metasurface samples are studied using the optical pump THz probe technique. Under various photoexcitations, the EIT spectra undergo significant modulations in terms of its resonance line shapes (amplitude and intensity contrast) leading to dynamic tailoring of the slow light characteristics. Group delay and delay bandwidth product values are modulated from 0.915 ps to 0.42 ps and 0.059 to 0.025 as the pump fluence increases from 0 to 62.5 nJ cm−2. This results in tunable slow THz light with group velocities ranging from 2.18 × 105 m s−1 to 4.76 × 105 m s−1, almost 54% change in group velocity. The observed tuning is attributed to the photo-induced modifications of the optoelectronic properties of the substrate layer. The demonstrated slow light scheme can provide opportunities for realizing dynamically tunable slow light devices, delay lines, and other ultrafast devices for THz domain.
Effect of dynamical screening on quantized longitudinal electrical conductivity in neutron star mergers
Authors: Sarkar S , Adhya S P
Published: August 2022

We present the calculation of longitudinal electrical conductivity in magnetized plasma considering dynamical screening in the context of binary neutron star mergers. We consider strongly quantizing domain for significant modification in the transport coefficient due to magnetic field. Boltzmann equation is solved to obtain dissipative component of the electrical conductivity tensor in presence of magnetic field. The longitudinal electrical conductivity is formulated considering dynamically screened medium with magnetically modified screening. Numerical evaluations show that the effect of screening on electrical conductivity is less whereas inclusion of dynamical screening results in profound modification. Dynamical screening reduces electrical conductivity leading to a reduction in relevant magnetic field decay time scale.
PVGAN: a generative adversarial network for object simplification in prosthetic vision
Authors: Elnabawy Reham H , Abdennadher Slim , Hellwich Olaf , Eldawlatly Seif
Published: August 2022

Objective. By means of electrical stimulation of the visual system, visual prostheses provide promising solution for blind patients through partial restoration of their vision. Despite the great success achieved so far in this field, the limited resolution of the perceived vision using these devices hinders the ability of visual prostheses users to correctly recognize viewed objects. Accordingly, we propose a deep learning approach based on generative adversarial networks (GANs), termed prosthetic vision GAN (PVGAN), to enhance object recognition for the implanted patients by representing objects in the field of view based on a corresponding simplified clip art version. Approach. To assess the performance, an axon map model was used to simulate prosthetic vision in experiments involving normally-sighted participants. In these experiments, four types of image representation were examined. The first and second types comprised presenting phosphene simulation of real images containing the actual high-resolution object, and presenting phosphene simulation of the real image followed by the clip art image, respectively. The other two types were utilized to evaluate the performance in the case of electrode dropout, where the third type comprised presenting phosphene simulation of only clip art images without electrode dropout, while the fourth type involved clip art images with electrode dropout. Main results. The performance was measured through three evaluation metrics which are the accuracy of the participants in recognizing the objects, the time taken by the participants to correctly recognize the object, and the confidence level of the participants in the recognition process. Results demonstrate that representing the objects using clip art images generated by the PVGAN model results in a significant enhancement in the speed and confidence of the subjects in recognizing the objects. Significance. These results demonstrate the utility of using GANs in enhancing the quality of images perceived using prosthetic vision.
Quantifying uncertainty about global and regional economic impacts of climate change
Authors: Bjordal Jenny , Storelvmo Trude , Smith Jr Anthony A
Published: August 2022

The economic impacts of climate change are highly uncertain. Two of the most important uncertainties are the sensitivity of the climate system and the so-called damage functions, which relate climate change to economic costs and benefits. Despite broad awareness of these uncertainties, it is unclear which of them is most important, especially at the regional level. Here we construct regional damage functions, based on two different global damage functions, and apply them to two climate models with vastly different climate sensitivities. We find that uncertainty in both climate sensitivity and aggregate economic damages per degree of warming are of similar importance for the global economic impact of climate change, with the decrease in global economic productivity ranging between 4% and 24% by the end of the century under a high-emission scenario. At the regional level, however, the effects of climate change can vary even more substantially, depending both on a region’s initial temperature and the amount of warming it experiences, with some regions gaining in productivity and others losing. The ranges of uncertainty are therefore potentially much larger at a regional level. For example, at the end of the century, under a high-emission scenario, we find that India’s productivity decreases between 13% and 57% and Russia’s increases between 24% and 74%, while Germany’s change in productivity ranges from an increase of 8% to a decrease of 4%. Our findings emphasise the importance of including these uncertainties in estimates of future economic impacts, as they are vital for the resulting impacts and thus policy implications.
How can blue carbon burial in seagrass meadows increase long-term, net sequestration of carbon? A critical review
Authors: Johannessen Sophia C
Published: August 2022

Blue carbon sequestration in seagrass meadows has been proposed as a low-risk, nature-based solution to offset carbon emissions and reduce the effects of climate change. Although the timescale of seagrass carbon burial is too short to offset emissions of ancient fossil fuel carbon, it has a role to play in reaching net zero within the modern carbon cycle. This review documents and discusses recent advances (from 2015 onwards) in the field of seagrass blue carbon. The net burial of carbon is affected by seagrass species, meadow connectivity, sediment bioturbation, grainsize, the energy of the local environment, and calcium carbonate formation. The burial rate of organic carbon can be calculated as the product of the sediment accumulation rate below the mixed layer and the burial concentration of organic carbon attributable to seagrass. A combination of biomarkers can identify seagrass material more precisely than bulk isotopes alone. The main threats related to climate change are sea-level rise, leading to a shoreline squeeze, and temperature rise, particularly during extreme events such as heat domes. In conclusion, some of the disagreement in the literature over methodology and the main controls on organic carbon burial likely results from real, regional differences in seagrasses and their habitat. Inter-regional collaboration could help to resolve the methodological differences and provide a more robust understanding of the global role of blue carbon sequestration in seagrass meadows.
Diffraction of an off-axis vector-beam by a tilted aperture
Authors: Remesh Ghanasyam , B S Athira , Gucchait Shyamal , Banerjee Ayan , Ghosh Nirmalya , Dutta Gupta Subhasish
Published: August 2022

Manifestations of orbital angular momentum induced effects in the diffraction of a radially polarized vector beam by an off-axis tilted aperture are studied both experimentally and theoretically. Experiments were carried out to extract the degree of circular polarization, which was shown to be proportional to the on-axis component of the spin angular momentum density. We report a clear separation of the regions of dominance of the right and left circular polarizations associated with positive and negative topological charges respectively, which is reminiscent of the standard vortex-induced transverse shift, albeit in the diffraction scenario. The experimental results are supported by model simulations and the agreement is quite satisfactory. The results are useful to appreciate the orbit-orbit related effects due to unavoidable misalignment problems (especially for vortex beams).
The integral geometric Satake equivalence in mixed characteristic
Authors: Yu Jize
Published: August 2022

Let

k
k

be an algebraically closed field of characteristic

p
p

. Denote by

W
(
k
)

W(k)

the ring of Witt vectors of

k
k

. Let

F
F

denote a totally ramified finite extension of

W
(
k
)
[
1

/

p
]

W(k)[1/p]

and

O

\mathcal {O}

its ring of integers. For a connected reductive group scheme

G
G

over

O

\mathcal {O}

, we study the category

P

L
+

G

(
G

r
G

,
Λ
)

\mathrm {P}_{L^+G}(Gr_G,\Lambda )

of

L
+

G

L^+G

-equivariant perverse sheaves in

Λ
\Lambda

-coefficient on the Witt vector affine Grassmannian

G

r
G

Gr_G

where

Λ
=

Z

ℓ

\Lambda =\mathbb {Z}_{\ell }

and

F

ℓ

 
(
ℓ
≠
p
)

\mathbb {F}_{\ell } \ (\ell \ne p)

, and prove that it is equivalent as a tensor category to the category of finitely generated

Λ
\Lambda

-representations of the Langlands dual group of

G
G

.
Preprint Highlight: Distinct regions of Helicobacter pylori's bactofilin CcmA regulate protein-protein interactions to control helical cell shape
Authors: Bisson-Filho Alexandre W.
Published: August 2022

Helicobacter pylori is a gram-negative bacterium commonly found in the human stomach. Its most famous feature is its helical shape, which is essential for invading the mucoid tissue and establishing infection that can cause gastrointestinal cancer. This study explored the regulatory role of a bactofilin, a cytoskeletal protein present in many bacteria and known to control cell shape and the assembly of subcellular structures. In vitro and in vivo experiments showed that the H. pylori bactofilin CcmA controls the curvature of cells by interacting with factors that build up or degrade the cell wall. The new mechanisms of CcmA self-inhibition and binding to specific cell shape factors represents a breakthrough in how we understand the role of bactofilins. It also suggests bactofilins as a possible therapeutic target against a broad range of pathogenic spiral-shaped bacteria.
Genome size and endoreplication in two pairs of cytogenetically contrasting species of Pulmonaria (Boraginaceae) in Central Europe
Authors: Koprivý Lukáš , Fráková Viera , Kolarčik Vladislav , Mártonfiová Lenka , Dudáš Matej , Mártonfi Pavol
Published: August 2022

Genome size is species-specific feature and commonly constant in an organism. In various plants, DNA content in cell nucleus is commonly increased in process of endoreplication, cellular-specific multiplication of DNA content without mitosis. This leads to the endopolyploidy, the presence of multiplied chromosome sets in a subset of cells. The relationship of endopolyploidy to species-specific genome size is rarely analysed and is not fully understood. While negative correlation between genome size and endopolyploidy level is supposed, this is species- and lineage-specific. In the present study, we shed light on this topic, exploring both genome size and endoreplication-induced DNA content variation in two pairs of morphologically similar species of Pulmonaria, P. obscura–P. officinalis and P. mollis–P. murinii. We aim (i) to characterize genome size and chromosome numbers in these species using cytogenetic, root-tip squashing and flow cytometry (FCM) techniques; (ii) to investigate the degree of endopolyploidy in various plant organs, including the root, stem, leaf, calyx and corolla using FCM; and (iii) to comprehensively characterize and compare the level of endopolyploidy and DNA content in various organs of all four species in relation to species systematic relationships and genome size variation. We have confirmed the diploid–dysploid nature of chromosome complements, and divergent genome sizes for Pulmonaria species: P. murinii with 2n = 2x = 14, 2.31 pg/2C, P. obscura 2n = 2x = 14, 2.69 pg/2C, P. officinalis 2n = 2x = 16, 2.96 pg/2C and P. mollis 2n = 2x = 18, 3.18 pg/2C. Endopolyploidy varies between species and organs, and we have documented 4C–8C in all four organs and up to 32C (64C) endopolyploid nuclei in stems at least in some species. Two species with lower genome sizes tend to have higher endopolyploidy levels than their closest relatives. Endoreplication-generated tissue-specific mean DNA content is increased and more balanced among species in all four organs compared to genome size. Our results argue for the narrow relationship between genome size and endopolyploidy in the present plant group within the genus Pulmonaria, and endopolyploidization seems to play a compensatory developmental role in organs of related morphologically similar species.
Kin do not always help: testing multiple hypotheses on nest feeding in a cooperatively breeding bird
Authors: Cousseau Laurence , Van de Loock Dries , Apfelbeck Beate , Githiru Mwangi , Matthysen Erik , Lens Luc
Published: August 2022

In cooperatively breeding species, group members may derive multiple benefits from helping to raise other individuals’ offspring, yet not all individuals do so. In this study, we tested predictions from the “kin selection”, “pay-to-stay”, “group augmentation” and “skills” hypotheses, to explain why group members feed nestlings of breeding placid greenbuls (Phyllastrephus placidus). In our study population, about 70% of the breeding pairs were accompanied by subordinates, and in 60% of these cases at least one subordinate helped in provisioning nestlings. In total, 80% of the subordinates were related to one or both breeders. In accordance with the “kin selection” hypothesis, and contrary to the “pay-to-stay” hypothesis, all the helpers were first-order kin of the breeding female (although relatedness to the breeding male did not explain variation in helping) and the presence of helpers was associated with increased survival of the breeding pair. However, the propensity to help varied among group members, as 46% of group members related to the breeding female did not feed nestlings. Younger helpers fed offspring more often than older ones, supporting the “skills” and “group augmentation” hypotheses. However, support for the “group augmentation” hypothesis was mixed since subordinate sex and group size did not explain additional variation in helping propensity and effort. We argue that in addition to indirect and direct benefits, also the costs of helping as well as other types of helping aside from provisioning must be considered to better understand variation in helping behavior.
CAPRIN1 haploinsufficiency causes a neurodevelopmental disorder with language impairment, ADHD and ASD
Authors: Pavinato Lisa , Delle Vedove Andrea , Carli Diana , Ferrero Marta , Carestiato Silvia , Howe Jennifer L , Agolini Emanuele , Coviello Domenico A , van de Laar Ingrid , Au Ping Yee Billie , Di Gregorio Eleonora , Fabbiani Alessandra , Croci Susanna , Mencarelli Maria Antonietta , Bruno Lucia P , Renieri Alessandra , Veltra Danai , Sofocleous Christalena , Faivre Laurence , Mazel Benoit , Safraou Hana , Denommé-Pichon Anne-Sophie , van Slegtenhorst Marjon A , Giesbertz Noor , van Jaarsveld Richard H , Childers Anna , Rogers R Curtis , Novelli Antonio , De Rubeis Silvia , Buxbaum Joseph D , Scherer Stephen W , Ferrero Giovanni Battista , Wirth Brunhilde , Brusco Alfredo
Published: August 2022

We describe an autosomal dominant disorder associated with loss-of-function variants in the Cell cycle associated protein 1 (CAPRIN1; MIM*601178). CAPRIN1 encodes a ubiquitous protein that regulates the transport and translation of neuronal mRNAs critical for synaptic plasticity, as well as mRNAs encoding proteins important for cell proliferation and migration in multiple cell types. We identified 12 cases with loss-of-function CAPRIN1 variants, and a neurodevelopmental phenotype characterized by language impairment/speech delay (100%), intellectual disability (83%), attention deficit hyperactivity disorder (82%) and autism spectrum disorder (67%). Affected individuals also had respiratory problems (50%), limb/skeletal anomalies (50%), developmental delay (42%) feeding difficulties (33%), seizures (33%) and ophthalmologic problems (33%).

In patient-derived lymphoblasts and fibroblasts, we showed a monoallelic expression of the wild-type allele, and a reduction of the transcript and protein compatible with a half dose. To further study pathogenic mechanisms, we generated sCAPRIN1+/− human induced pluripotent stem cells via CRISPR–Cas9 mutagenesis and differentiated them into neuronal progenitor cells and cortical neurons. CAPRIN1 loss caused reduced neuronal processes, overall disruption of the neuronal organization and an increased neuronal degeneration. We also observed an alteration of mRNA translation in CAPRIN1+/− neurons, compatible with its suggested function as translational inhibitor. CAPRIN1+/− neurons also showed an impaired calcium signalling and increased oxidative stress, two mechanisms that may directly affect neuronal networks development, maintenance and function. According to what was previously observed in the mouse model, measurements of activity in CAPRIN1+/− neurons via micro-electrode arrays indicated lower spike rates and bursts, with an overall reduced activity. In conclusion, we demonstrate that CAPRIN1 haploinsufficiency causes a novel autosomal dominant neurodevelopmental disorder and identify morphological and functional alterations associated with this disorder in human neuronal models.
‘Hippocampal innate inflammatory gliosis only’ in pharmacoresistant temporal lobe epilepsy
Authors: Grote Alexander , Heiland Dieter-Henrik , Taube Julia , Helmstaedter Christoph , Ravi Vidhya M , Will Paulina , Hattingen Elke , Schüre Jan-Rüdiger , Witt Juri-Alexander , Reimers Annika , Elger Christian , Schramm Johannes , Becker Albert J , Delev Daniel
Published: August 2022

Drug-resistant mesial-temporal lobe epilepsy is a devastating disease with seizure onset in the hippocampal formation. A fraction of hippocampi samples from epilepsy-surgical procedures reveals a peculiar histological pattern referred to as ‘gliosis only’ with unresolved pathogenesis and enigmatic sequelae. Here, we hypothesize that ‘gliosis only’ represents a particular syndrome defined by distinct clinical and molecular characteristics.

We curated an in-depth multiparameter integration of systematic clinical, neuropsychological as well as neuropathological analysis from a consecutive cohort of 627 patients, who underwent hippocampectomy for drug-resistant temporal lobe epilepsy. All patients underwent either classic anterior temporal lobectomy or selective amygdalohippocampectomy. On the basis of their neuropathological exam, patients with hippocampus sclerosis and ‘gliosis only’ were characterized and compared within the whole cohort and within a subset of matched pairs. Integrated transcriptional analysis was performed to address molecular differences between both groups.

‘Gliosis only’ revealed demographics, clinical and neuropsychological outcome fundamentally different from hippocampus sclerosis. ‘Gliosis only’ patients had a significantly later seizure onset (16.3 versus 12.2 years, P = 0.005) and worse neuropsychological outcome after surgery compared to patients with hippocampus sclerosis. Epilepsy was less amendable by surgery in ‘gliosis only’ patients, resulting in a significantly worse rate of seizure freedom after surgery in this subgroup (43% versus 68%, P = 0.0001, odds ratio = 2.8, confidence interval 1.7–4.7). This finding remained significant after multivariate and matched-pairs analysis. The ‘gliosis only’ group demonstrated pronounced astrogliosis and lack of significant neuronal degeneration in contrast to characteristic segmental neuron loss and fibrillary astrogliosis in hippocampus sclerosis. RNA-sequencing of gliosis only patients deciphered a distinct transcriptional programme that resembles an innate inflammatory response of reactive astrocytes.

Our data indicate a new temporal lobe epilepsy syndrome for which we suggest the term ‘Innate inflammatory gliosis only’. ‘Innate inflammatory gliosis only’ is characterized by a diffuse gliosis pattern lacking restricted hippocampal focality and is poorly controllable by surgery. Thus, ‘innate inflammatory gliosis only’ patients need to be clearly identified by presurgical examination paradigms of pharmacoresistant temporal lobe epilepsy patients; surgical treatment of this subgroup should be considered with great precaution. ‘Innate inflammatory gliosis only’ requires innovative pharmacotreatment strategies.
Astrogliosis in aging and Parkinson’s disease dementia: a new clinical study with 11C-BU99008 PET
Authors: Mohamed Mohamed A , Zeng Zhou , Gennaro Marta , Lao-Kaim Nicholas P , Myers Jim F M , Calsolaro Valeria , Femminella Grazia Daniela , Tyacke Robin J , Martin-Bastida Antonio , Gunn Roger N , Nutt David J , Edison Paul , Piccini Paola , Roussakis Andreas-Antonios
Published: August 2022

The role of astrogliosis in the pathology of brain aging and neurodegenerative diseases has recently drawn great attention. Imidazoline-2 binding sites represent a possible target to map the distribution of reactive astrocytes. In this study, we use 11C-BU99008, an imidazoline-2 binding sites-specific PET radioligand, to image reactive astrocytes in vivo in healthy controls and patients with established Parkinson’s disease dementia. Eighteen healthy controls (age: 45–78 years) and six patients with Parkinson’s disease dementia (age: 64–77 years) had one 11C-BU99008 PET-CT scan with arterial input function. All subjects underwent one 3 T MRI brain scan to facilitate the analysis of the PET data and to capture individual cerebral atrophy. Regional 11C-BU99008 volumes of distribution were calculated for each subject by the two-tissue compartmental modelling. Positive correlations between 11C-BU99008 volumes of distribution values and age were found for all tested regions across the brain within healthy controls (P < 0.05); furthermore, multiple regression indicated that aging affects 11C-BU99008 volumes of distribution values in a region-specific manner. Independent samples t-test indicated that there was no significant group difference in 11C-BU99008 volumes of distribution values between Parkinson’s disease dementia (n = 6; mean age = 71.97 ± 4.66 years) and older healthy controls (n = 9; mean age = 71.90 ± 5.51 years). Our data set shows that astrogliosis is common with aging in a region-specific manner. However, in this set-up, 11C-BU99008 PET cannot differentiate patients with Parkinson’s disease dementia from healthy controls of similar age.