bluuebunny/crossref_metadata_2025 huggingface dataset:
Nondiffusive Pitch‐Angle Scattering of a Distribution of Energetic Particles by Coherent Whistler Waves
Authors: Yoon Young Dae , Bellan Paul M.
Published: June 2020

Whether or not coherent magnetospheric whistler waves play important roles in the pitch‐angle scattering of energetic particles is a crucial question in magnetospheric physics. The interaction of a thermal distribution of energetic particles with coherent whistler waves is thus investigated. The distribution is prescribed by the Maxwell‐Jüttner distribution, which is a relativistic generalization of the Maxwell‐Boltzmann distribution. Coherent whistler waves are modeled by circularly polarized waves propagating parallel to the background magnetic field. It is shown that for parameters relevant to magnetospheric chorus, a significant fraction (1–5%) of the energetic particle population undergoes drastic, nondiffusive pitch‐angle scattering by coherent chorus. The scaling of this fraction with the wave amplitude may also explain the association of relativistic microbursts to large‐amplitude chorus. A much improved condition for large pitch‐angle scattering is presented that is related to, but may or may not include the exact resonance condition depending on the particle's initial conditions. The theory reveals a critical mechanism not contained in the widely used second‐order trapping theory.
Three‐Dimensional Structure, Ground Rupture Hazards, and Static Stress Models for Complex Nonplanar Thrust Faults in the Ventura Basin, Southern California
Authors: Hughes A. , Bell R. E. , Mildon Z. K. , Rood D. H. , Whittaker A. C. , Rockwell T. K. , Levy Y. , DeVecchio D. E. , Marshall S. T. , Nicholson C.
Published: June 2020

To investigate the subsurface geometry of a recently discovered, seismically active fault in the Ventura basin, southern California, USA, we present a series of cross sections and a new three‐dimensional fault model across the Southern San Cayetano fault (SSCF) based on integration of surface data with petroleum industry well log data. Additionally, the fault model for the SSCF, along with models of other regional faults extracted from the Southern California Earthquake Center three‐dimensional Community Fault Model, are incorporated in static Coulomb stress modeling to investigate static Coulomb stress transfer between thrust faults with complex geometry and to further our understanding of stress transfer in the Ventura basin. The results of the subsurface well investigation provide evidence for a low‐angle SSCF that dips ~15° north and connects with the western section of the San Cayetano fault around 1.5–3.5 km depth. We interpret the results of static Coulomb stress models to partly explain contrasting geomorphic expression between different sections of the San Cayetano fault and a potential mismatch in timings between large‐magnitude uplift events suggested by paleoseismic studies on the Pitas Point, Ventura, and San Cayetano faults. In addition to new insights into the structure and potential rupture hazard of a recently discovered active reverse fault in a highly populated area of southern California, this study provides a simple method to model static Coulomb stress transfer on complex geometry faults in fold and thrust belts.
Surface Slip Distribution Along the West Helanshan Fault, Northern China, and Its Implications for Fault Behavior
Authors: Bi Haiyun , Zheng Wenjun , Lei Qiyun , Zeng Jiangyuan , Zhang Peizhen , Chen Gan
Published: June 2020

High‐resolution topographic data sets have now become increasingly available, which allows for remotely measuring and analyzing offset features and their associated slip distributions at a very high resolution along a fault, hence providing important insights into the fault behavior. The West Helanshan Fault is a Holocene active right‐lateral strike‐slip fault located at the junction of the Tibetan Plateau, Alashan, and Ordos blocks. In this study, a 2‐m‐resolution DEM of the West Helanshan Fault was built from the WorldView‐3 stereo satellite images (0.5 m). Combined with the high‐resolution topography acquired from the Unmanned Aerial Vehicle (UAV) images based on the Structure from Motion (SfM) method, a total of 180 lateral offsets and 201 vertical displacements were acquired along ~50 km of the fault. By statistical analysis of the offset observations and constructing the cumulative slip profiles, we conclude that large paleoearthquakes have produced characteristic slip accumulation along the fault with a right‐lateral slip of ~3 m and a vertical slip of ~1 m, rupturing at least two segments of the fault simultaneously, which corresponds to a moment magnitude ofMw7.1 ~ 7.5. The cumulative slip profiles suggest that the fault has likely propagated northward over its lifetime, and the south segment may be the most mature section of the fault where larger coseismic slip of earthquake ruptures may occur. The ratio of lateral to vertical displacement has remained constant (~3:1) through multiple successive events, indicating that the fault has maintained the same kinematic style over the last few thousands of years.
Improved Representation of Underwater Light Field and Its Impact on Ecosystem Dynamics: A Study in the North Sea
Authors: Skákala Jozef , Bruggeman Jorn , Brewin Robert J. W. , Ford David A. , Ciavatta Stefano
Published: June 2020

Understanding ecosystem state on the North‐West European (NWE) Shelf is of major importance for both economy and climate research. The purpose of this work is to advance our modeling of in‐water optics on the NWE Shelf, with important implications for how we model primary productivity, as well as for assimilation of water‐leaving radiances. We implement a stand‐alone bio‐optical module into the existing coupled physical‐biogeochemical model configuration. The advantage of the bio‐optical module, when compared to the preexisting light scheme is that it resolves the underwater light spectrally and distinguishes between direct and diffuse downwelling streams. The changed underwater light compares better with both satellite and in situ observations. The module lowered the underwater photosynthetically active radiation, decreasing the simulated primary productivity, but overall, the improved underwater light had relatively limited impact on the phytoplankton seasonal dynamics. We showed that the model skill in representing phytoplankton seasonal cycle (e.g., phytoplankton bloom) can be substantially improved either by assimilation of satellite phytoplankton functional type (PFT) chlorophyll, or by assimilating a novel PFT absorption product. Assimilation of the two PFT products yields similar results, with an important difference in the PFT community structure. Both assimilative runs lead to lower plankton biomass and increase the nutrient concentrations. We discuss some future directions on how to improve our model skill in biogeochemistry without using assimilation, for example, by improving nutrient forcing, retuning the model parameters, and using the bio‐optical module to provide a two‐way physical‐biogeochemical coupling, improving the consistency between model physical and biogeochemical components.
Time‐Lapse Seismic Imaging of Oceanic Fronts and Transient Lenses Within South Atlantic Ocean
Authors: Gunn Kathryn L. , White Nicky , Caulfield Colm‐cille P.
Published: June 2020

Oceanic fronts play a pivotal role in controlling water mass transfer, although little is known about deep frontal structure on appropriate temporal and spatial scales. Here, we present a sequence of calibrated time‐lapse images from a three‐dimensional seismic survey that straddles the Brazil‐Malvinas Confluence—a significant feature of the meridional overturning circulation. Eight vertical transects reveal the evolution of a major front. It is manifest as a discrete planar surface that dips at less than 2° and is traceable to 1.5–2 km depth. Its shape and surface expression are consistent with sloping isopycnal surfaces of the calculated potential density field and with coeval sea surface temperature measurements, respectively. Within the top ∼1 km, where cold fresh water subducts beneath warm salty water, a series of tilted lenses are banked up against the sharply defined front. The largest of these structures is centered at 700 m depth and is cored by cold fresh water. Time‐lapse imagery demonstrates that this tilted lens grows and decays over 9 days. It has a maximum diameter of <34±0.13 km and a maximum height of <750±10 m. Beneath 1 km, where horizontal density gradients are negligible, numerous deforming lenses and filaments on length scales of 10–100 km are being swept toward the advecting front.
Modified GIC Estimation Using 3‐D Earth Conductivity
Authors: Kelbert Anna , Lucas Greg M.
Published: June 2020

Geomagnetically induced currents (GICs) are quasi‐direct current (DC) electric currents that flow in technological conductors during geomagnetic storms. Extreme GICs are hazardous to man‐made infrastructure. GICs enter and exit the technological systems, such as the electric power grid, at grounding points, and their magnitudes depend on the currents that flow underground. They are, therefore, a function of the Earth's electrical conductivity, represented at ground level as Earth impedances, as well as the resistance parameters of the power network. Traditional GIC estimation practices are based on Earth impedances obtained from laterally homogeneous or piecewise layered‐Earth models. We refer to these methods, collectively, as the 1‐D approximation. However, GIC hazard mitigation can be improved with more accurate GIC modeling that takes the spatially heterogeneous Earth's conductivity into account. Here, we propose a modified approximation for GIC estimation that is very similar to the 1‐D approximation but is instead derived from empirical 3‐D Earth impedances. Our formulation sets up the computation of static, frequency‐dependent power line telluric response functions, which, once computed, may be considered part of the power grid system model. These response functions may then be used for historical scenario analysis of GIC hazards and for simplified real‐time, albeit approximate, GIC estimation in a power grid. This modest modification to the simpler local field formulation approach avoids real‐time integration of geoelectric fields along power lines while taking the realistic 3‐D Earth into account in a rigorous manner. Once implemented, the method provides a power grid operator with the benefits of convenience and computational speed for a first look real‐time operational GIC hazard assessment. We estimate that the proposed modified 3‐D GIC modeling approach produces GIC values that are well within 50% of those obtained with the full‐scale power line integration of spatially variable geoelectric fields, for storms comparable in scale to the 2003 Halloween storm, all geological structures, and power lines located in the contiguous United States and other low‐ to middle‐latitude regions.
Solar Wind Prediction Using Deep Learning
Authors: Upendran Vishal , Cheung Mark C. M. , Hanasoge Shravan , Krishnamurthi Ganapathy
Published: June 2020

Emanating from the base of the Sun's corona, the solar wind fills the interplanetary medium with a magnetized stream of charged particles whose interaction with the Earth's magnetosphere has space weather consequences such as geomagnetic storms. Accurately predicting the solar wind through measurements of the spatiotemporally evolving conditions in the solar atmosphere is important but remains an unsolved problem in heliophysics and space weather research. In this work, we use deep learning for prediction of solar wind (SW) properties. We use extreme ultraviolet images of the solar corona from space‐based observations to predict the SW speed from the National Aeronautics and Space Administration (NASA) OMNIWEB data set, measured at Lagragian Point 1. We evaluate our model against autoregressive and naive models and find that our model outperforms the benchmark models, obtaining a best fit correlation of 0.55 ± 0.03 with the observed data. Upon visualization and investigation of how the model uses data to make predictions, we find higher activation at the coronal holes for fast wind prediction (≈3 to 4 days prior to prediction), and at the active regions for slow wind prediction. These trends bear an uncanny similarity to the influence of regions potentially being the sources of fast and slow wind, as reported in literature. This suggests that our model was able to learn some of the salient associations between coronal and solar wind structure without built‐in physics knowledge. Such an approach may help us discover hitherto unknown relationships in heliophysics data sets.
miR-410 induces both epithelial–mesenchymal transition and radioresistance through activation of the PI3K/mTOR pathway in non-small cell lung cancer
Authors: Yuan Yue , Liao Hu , Pu Qiang , Ke Xixian , Hu Xueting , Ma Yongfang , Luo Xinmei , Jiang Qianqian , Gong Yi , Wu Min , Liu Lunxu , Zhu Wen
Published: June 2020

Radiotherapy remains one of the major treatments for non-small cell lung cancer (NSCLC) patients; whereas intrinsic or acquired radioresistance limits its efficacy. Nevertheless, most studies so far have only focused on acquired resistance. The exact mechanisms of intrinsic radioresistance in NSCLC are still unclear. A few studies have suggested that epithelial–mesenchymal transition (EMT) is associated with radioresistance in NSCLC. However, little is known about whether the abnormal expression of specific microRNAs induces both EMT and radioresistance. We previously found that miR-410 has multiple roles as an oncomiRNA in NSCLC. In this study, we revealed that miR-410 overexpression promoted EMT and radioresistance, accompanied by enhanced DNA damage repair both in vitro and in vivo. Conversely, knockdown of miR-410 showed the opposite effects. We further demonstrated that PTEN was a direct target of miR-410 by using bioinformatic tools and dual-luciferase reporter assays, and the miR-410-induced EMT and radioresistance were reversed by PI3K, Akt, and mTOR inhibitors or by restoring the expression of PTEN in NSCLC cells. In addition, we preliminarily found that the expression of miR-410 was positively correlated with EMT and negatively associated with the expression of PTEN in NSCLC specimens. In summary, these results demonstrated that miR-410 is an important regulator on enhancing both NSCLC EMT and radioresistance by targeting the PTEN/PI3K/mTOR axis. The findings suggest that miR-410-induced EMT might significantly contribute to the enhanced radioresistance. Therefore, miR-410 may serve as a potential biomarker or therapeutic target for NSCLC radiotherapy.
Synthesis of highly dispersed Pt nanoparticles into carbon supports by fluidized bed reactor atomic layer deposition to boost PEMFC performance
Authors: Lee Woo-Jae , Bera Susanta , Kim Chang Min , Koh Eun-Kyong , Hong Woong-Pyo , Oh Seung-Jeong , Cho EunAe , Kwon Se-Hun
Published: June 2020

The performance of proton exchange membrane fuel cells (PEMFCs) depends on the controlled size, dispersion and density of Pt nanoparticles (NPs) on carbon supports, which are strongly affected by the carbon characteristics and fabrication methods. Here, we demonstrated a high-performance Pt/carbon catalyst for PEMFCs using fluidized bed reactor atomic layer deposition (FBR-ALD) that was realized by an effective matching of the carbon supports for the FBR-ALD process and an optimization of the ionomer content during the preparation of the membrane electrode assembly (MEA). For this, the synthesis of Pt NPs was conducted on two porous supports (Vulcan XC-72R and functionalized carbon) by FBR-ALD. The functionalized carbon possessed a higher surface area with a large pore volume, abundant defects in a disordered structure and a large number of oxygen functional groups compared to those of the well-known Vulcan carbon. The favorable surface characteristics of the functionalized carbon for nucleation produced Pt particles with an increased uniformity and density and a narrow size range, which led to a higher electrochemical surface area (ECSA) than that of Pt/Vulcan carbon and commercial Pt/carbon. The PEMFC test of the respective Pt/carbon samples was investigated, and highly dense and uniform Pt/functionalized-carbon showed the highest performance through optimization of the higher ionomer content compared to that for the ALD Pt growth on Vulcan carbon and commercial Pt/carbon. In addition, the Pt catalyst using ALD demonstrated a significant long-term stability for the PEMFC. This finding demonstrates the remarkable advantages of FBR-ALD for the fabrication of Pt/carbon and the ability of functionalized carbon supports to achieve a high PEMFC efficiency and an enhanced durability.
Large-scale simulation of biomembranes incorporating realistic kinetics into coarse-grained models
Authors: Sadeghi Mohsen , Noé Frank
Published: June 2020

Biomembranes are two-dimensional assemblies of phospholipids that are only a few nanometres thick, but form micrometre-sized structures vital to cellular function. Explicit molecular modelling of biologically relevant membrane systems is computationally expensive due to the large number of solvent particles and slow membrane kinetics. Coarse-grained solvent-free membrane models offer efficient sampling but sacrifice realistic kinetics, thereby limiting the ability to predict pathways and mechanisms of membrane processes. Here, we present a framework for integrating coarse-grained membrane models with continuum-based hydrodynamics. This framework facilitates efficient simulation of large biomembrane systems with large timesteps, while achieving realistic equilibrium and non-equilibrium kinetics. It helps to bridge between the nanometer/nanosecond spatiotemporal resolutions of coarse-grained models and biologically relevant time- and lengthscales. As a demonstration, we investigate fluctuations of red blood cells, with varying cytoplasmic viscosities, in 150-milliseconds-long trajectories, and compare kinetic properties against single-cell experimental observations.
Bacterial symbionts support larval sap feeding and adult folivory in (semi-)aquatic reed beetles
Authors: Reis Frank , Kirsch Roy , Pauchet Yannick , Bauer Eugen , Bilz Lisa Carolin , Fukumori Kayoko , Fukatsu Takema , Kölsch Gregor , Kaltenpoth Martin
Published: June 2020

Symbiotic microbes can enable their host to access untapped nutritional resources but may also constrain niche space by promoting specialization. Here, we reconstruct functional changes in the evolutionary history of the symbiosis between a group of (semi-)aquatic herbivorous insects and mutualistic bacteria. Sequencing the symbiont genomes across 26 species of reed beetles (Chrysomelidae, Donaciinae) spanning four genera indicates that the genome-eroded mutualists provide life stage-specific benefits to larvae and adults, respectively. In the plant sap-feeding larvae, the symbionts are inferred to synthesize most of the essential amino acids as well as the B vitamin riboflavin. The adult reed beetles’ folivory is likely supported by symbiont-encoded pectinases that complement the host-encoded set of cellulases, as revealed by transcriptome sequencing. However, mapping the occurrence of the symbionts’ pectinase genes and the hosts’ food plant preferences onto the beetles’ phylogeny reveals multiple independent losses of pectinase genes in lineages that switched to feeding on pectin-poor plants, presumably constraining their hosts’ subsequent adaptive potential.
MCM8IP activates the MCM8-9 helicase to promote DNA synthesis and homologous recombination upon DNA damage
Authors: Huang Jen-Wei , Acharya Ananya , Taglialatela Angelo , Nambiar Tarun S. , Cuella-Martin Raquel , Leuzzi Giuseppe , Hayward Samuel B. , Joseph Sarah A. , Brunette Gregory J. , Anand Roopesh , Soni Rajesh K. , Clark Nathan L. , Bernstein Kara A. , Cejka Petr , Ciccia Alberto
Published: June 2020

Homologous recombination (HR) mediates the error-free repair of DNA double-strand breaks to maintain genomic stability. Here we characterize C17orf53/MCM8IP, an OB-fold containing protein that binds ssDNA, as a DNA repair factor involved in HR. MCM8IP-deficient cells exhibit HR defects, especially in long-tract gene conversion, occurring downstream of RAD51 loading, consistent with a role for MCM8IP in HR-dependent DNA synthesis. Moreover, loss of MCM8IP confers cellular sensitivity to crosslinking agents and PARP inhibition. Importantly, we report that MCM8IP directly associates with MCM8-9, a helicase complex mutated in primary ovarian insufficiency, and RPA1. We additionally show that the interactions of MCM8IP with MCM8-9 and RPA facilitate HR and promote replication fork progression and cellular viability in response to treatment with crosslinking agents. Mechanistically, MCM8IP stimulates the helicase activity of MCM8-9. Collectively, our work identifies MCM8IP as a key regulator of MCM8-9-dependent DNA synthesis during DNA recombination and replication.
Tunable resistivity exponents in the metallic phase of epitaxial nickelates
Authors: Guo Qikai , Farokhipoor Saeedeh , Magén César , Rivadulla Francisco , Noheda Beatriz
Published: June 2020

We report a detailed analysis of the electrical resistivity exponent of thin films of NdNiO3 as a function of epitaxial strain. Thin films under low strain conditions show a linear dependence of the resistivity versus temperature, consistent with a classical Fermi gas ruled by electron-phonon interactions. In addition, the apparent temperature exponent, n, can be tuned with the epitaxial strain between n = 1 and n = 3. We discuss the critical role played by quenched random disorder in the value of n. Our work shows that the assignment of Fermi/Non-Fermi liquid behaviour based on experimentally obtained resistivity exponents requires an in-depth analysis of the degree of disorder in the material.
Cell size sets the diameter of the budding yeast contractile ring
Authors: Kukhtevich I. V. , Lohrberg N. , Padovani F. , Schneider R. , Schmoller K. M.
Published: June 2020

The formation and maintenance of subcellular structures and organelles with a well-defined size is a key requirement for cell function, yet our understanding of the underlying size control mechanisms is limited. While budding yeast cell polarization and subsequent assembly of a septin ring at the site of bud formation has been successfully used as a model for biological self-assembly processes, the mechanisms that set the size of the septin ring at the bud neck are unknown. Here, we use live-cell imaging and genetic manipulation of cell volume to show that the septin ring diameter increases with cell volume. This cell-volume-dependence largely accounts for modulations of ring size due to changes in ploidy and genetic manipulation of cell polarization. Our findings suggest that the ring diameter is set through the dynamic interplay of septin recruitment and Cdc42 polarization, establishing it as a model for size homeostasis of self-assembling organelles.
Norovirus infection causes acute self-resolving diarrhea in wild-type neonatal mice
Authors: Roth Alexa N. , Helm Emily W. , Mirabelli Carmen , Kirsche Erin , Smith Jonathan C. , Eurell Laura B. , Ghosh Sourish , Altan-Bonnet Nihal , Wobus Christiane E. , Karst Stephanie M.
Published: June 2020

Human noroviruses are the leading cause of severe childhood diarrhea worldwide, yet we know little about their pathogenic mechanisms. Murine noroviruses cause diarrhea in interferon-deficient adult mice but these hosts also develop systemic pathology and lethality, reducing confidence in the translatability of findings to human norovirus disease. Herein we report that a murine norovirus causes self-resolving diarrhea in the absence of systemic disease in wild-type neonatal mice, thus mirroring the key features of human norovirus disease and representing a norovirus small animal disease model in wild-type mice. Intriguingly, lymphocytes are critical for controlling acute norovirus replication while simultaneously contributing to disease severity, likely reflecting their dual role as targets of viral infection and key components of the host response.
Local auxin competition explains fragmented differentiation patterns
Authors: Moret Bernard , Marhava Petra , Aliaga Fandino Ana Cecilia , Hardtke Christian S. , ten Tusscher Kirsten H. W.
Published: June 2020

Trajectories of cellular ontogeny are tightly controlled and often involve feedback-regulated molecular antagonism. For example, sieve element differentiation along developing protophloem cell files of Arabidopsis roots requires two antagonistic regulators of auxin efflux. Paradoxically, loss-of-function in either regulator triggers similar, seemingly stochastic differentiation failures of individual sieve element precursors. Here we show that these patterning defects are distinct and non-random. They can be explained by auxin-dependent bistability that emerges from competition for auxin between neighboring cells. This bistability depends on the presence of an auxin influx facilitator, and can be triggered by either flux enhancement or repression. Our results uncover a hitherto overlooked aspect of auxin uptake, and highlight the contributions of local auxin influx, efflux and biosynthesis to protophloem formation. Moreover, the combined experimental-modeling approach suggests that without auxin efflux homeostasis, auxin influx interferes with coordinated differentiation.
Objective Assessment of Cerebellar Ataxia: A Comprehensive and Refined Approach
Authors: Kashyap Bipasha , Phan Dung , Pathirana Pubudu N. , Horne Malcolm , Power Laura , Szmulewicz David
Published: June 2020

Parametric analysis of Cerebellar Ataxia (CA) could be of immense value compared to its subjective clinical assessments. This study focuses on a comprehensive scheme for objective assessment of CA through the instrumented versions of 9 commonly used neurological tests in 5 domains- speech, upper limb, lower limb, gait and balance. Twenty-three individuals diagnosed with CA to varying degrees and eleven age-matched healthy controls were recruited. Wearable inertial sensors and Kinect camera were utilised for data acquisition. Binary and multilabel discrimination power and intra-domain relationships of the features extracted from the sensor measures and the clinical scores were compared using Graph Theory, Centrality Measures, Random Forest binary and multilabel classification approaches. An optimal subset of 13 most important Principal Component (PC) features were selected for CA-control classification. This classification model resulted in an impressive performance accuracy of 97% (F1 score = 95.2%) with Holmesian dimensions distributed as 47.7% Stability, 6.3% Timing, 38.75% Accuracy and 7.24% Rhythmicity. Another optimal subset of 11 PC features demonstrated an F1 score of 84.2% in mapping the total 27 PC across 5 domains during CA multilabel discrimination. In both cases, the balance (Romberg) test contributed the most (31.1% and 42% respectively), followed by the peripheral tests whereas gait (Walking) test contributed the least. These findings paved the way for a better understanding of the feasibility of an instrumented system to assist informed clinical decision-making.
Photonic Readout of Superconducting Nanowire Single Photon Counting Detectors
Authors: de Cea Marc , Wollman Emma E. , Atabaki Amir H. , Gray Dodd J. , Shaw Matthew D. , Ram Rajeev J.
Published: June 2020

Scalable, low power, high speed data transfer between cryogenic (0.1–4 K) and room temperature environments is essential for the realization of practical, large-scale systems based on superconducting technologies. A promising approach to overcome the limitations of conventional wire-based readout is the use of optical fiber communication. Optical fiber presents a 100–1,000x lower heat load than conventional electrical wiring, relaxing the requirements for thermal anchoring, and is also immune to electromagnetic interference, which allows routing of sensitive signals with improved robustness to noise and crosstalk. Most importantly, optical fibers allow for very high bandwidth densities (in the Tbps/mm2 range) by carrying multiple signals through the same physical fiber (Wavelength Division Multiplexing, WDM). Here, we demonstrate for the first time optical readout of a superconducting nanowire single-photon detector (SNSPD) directly coupled to a CMOS photonic modulator, without the need for an interfacing device. By operating the modulator in the forward bias regime at a temperature of 3.6 K, we achieve very high modulation efficiency (1,000–10,000 pm/V) and a low input impedance of 500 Ω with a low power dissipation of 40 μW. This allows us to obtain optical modulation with the low, millivolt-level signal generated by the SNSPD.
Molecular and Histopathological Study on the Ameliorative Impacts of Petroselinum Crispum and Apium Graveolens against Experimental Hyperuricemia
Authors: Soliman Mohamed Mohamed , Nassan Mohamed Abdo , Aldhahrani Adil , Althobaiti Fayez , Mohamed Wafaa Abdou
Published: June 2020

Hyperuricemia is an abnormal metabolic condition characterized by an increase in uric acid levels in the blood. It is the cause of gout, manifested by inflammatory arthritis, pain and disability. This study examined the possible ameliorative impacts of parsley (PAR) and celery (CEL) as hypouricemic agents at biochemical, molecular and cellular levels. PAR and CEL alone or in combination were orally administered to hyperuricemic (HU) mice and control mice for 10 consecutive days. Serum levels of uric acid and blood urea nitrogen (BUN), xanthine oxidase activity, antioxidants, inflammatory (IL-1β and TNF-α) and anti-inflammatory cytokines (IL-10) were measured. mRNA expression of urate transporters and uric acid excretion genes in renal tissues were examined using qRT-PCR (quantitative real time PCR). Normal histology and immunoreactivity of transforming growth factor-beta 1 (TGF-β1) in kidneys was examined. Administration of PAR and CEL significantly reduced serum BUN and uric acids in HU mice, ameliorated changes in malondialdehyde, catalase, and reduced glutathione, glutathione peroxidase (GPX), IL-1β, TNF-α and IL-10 in hyperuricemic mice. Both effectively normalized the alterations in mURAT-1, mGLUT-9, mOAT-1 and mOAT-3 expression, as well as changes in TGF-β1 immunoreactivity. Interestingly, combined administration of PAR and CEL mitigated all examined measurements synergistically, and improved renal dysfunction in the hyperuricemic mice. The study concluded that PAR and CEL can potentially reduce damaging cellular, molecular and biochemical effects of hyperuricemia both individually and in combination.
Accelerating massively parallel hemodynamic models of coarctation of the aorta using neural networks
Authors: Feiger Bradley , Gounley John , Adler Dale , Leopold Jane A. , Draeger Erik W. , Chaudhury Rafeed , Ryan Justin , Pathangey Girish , Winarta Kevin , Frakes David , Michor Franziska , Randles Amanda
Published: June 2020

Comorbidities such as anemia or hypertension and physiological factors related to exertion can influence a patient’s hemodynamics and increase the severity of many cardiovascular diseases. Observing and quantifying associations between these factors and hemodynamics can be difficult due to the multitude of co-existing conditions and blood flow parameters in real patient data. Machine learning-driven, physics-based simulations provide a means to understand how potentially correlated conditions may affect a particular patient. Here, we use a combination of machine learning and massively parallel computing to predict the effects of physiological factors on hemodynamics in patients with coarctation of the aorta. We first validated blood flow simulations against in vitro measurements in 3D-printed phantoms representing the patient’s vasculature. We then investigated the effects of varying the degree of stenosis, blood flow rate, and viscosity on two diagnostic metrics – pressure gradient across the stenosis (ΔP) and wall shear stress (WSS) - by performing the largest simulation study to date of coarctation of the aorta (over 70 million compute hours). Using machine learning models trained on data from the simulations and validated on two independent datasets, we developed a framework to identify the minimal training set required to build a predictive model on a per-patient basis. We then used this model to accurately predict ΔP (mean absolute error within 1.18 mmHg) and WSS (mean absolute error within 0.99 Pa) for patients with this disease.
Termite’s Twisted Mandible Presents Fast, Powerful, and Precise Strikes
Authors: Kuan Kuan-Chih , Chiu Chun-I , Shih Ming-Chih , Chi Kai-Jung , Li Hou-Feng
Published: June 2020

The asymmetric mandibles of termites are hypothetically more efficient, rapid, and powerful than the symmetric mandibles of snap-jaw ants or termites. We investigated the velocity, force, precision, and defensive performance of the asymmetric mandibular snaps of a termite species, Pericapritermes nitobei. Ultrahigh-speed recordings of termites revealed a new record in biological movement, with a peak linear velocity of 89.7–132.4 m/s within 8.68 μs after snapping, which caused an impact force of 105.8–156.2 mN. High-speed video recordings of ball-strike experiments on termites were analysed using the principle of energy conservation; the left mandibles precisely hit metal balls at the left-to-front side with a maximum linear velocity of 80.3 ± 15.9 m/s (44.0–107.7 m/s) and an impact force of 94.7 ± 18.8 mN (51.9–127.1 mN). In experimental fights between termites and ant predators, Pe. nitobei killed 90–100% of the generalist ants with a single snap and was less likely to harm specialist ponerine ants. Compared with other forms, the asymmetric snapping mandibles of Pe. nitobei required less elastic energy to achieve high velocity. Moreover, the ability of P. nitobei to strike its target at the front side is advantageous for defence in tunnels.
Selective Induction of Human Autonomic Neurons Enables Precise Control of Cardiomyocyte Beating
Authors: Takayama Yuzo , Kushige Hiroko , Akagi Yuka , Suzuki Yutaka , Kumagai Yutaro , Kida Yasuyuki S.
Published: June 2020

The autonomic nervous system (ANS) regulates tissue homeostasis and remodelling through antagonistic effects of noradrenergic sympathetic and cholinergic parasympathetic signalling. Despite numerous reports on the induction of sympathetic neurons from human pluripotent stem cells (hPSCs), no induction methods have effectively derived cholinergic parasympathetic neurons from hPSCs. Considering the antagonistic effects of noradrenergic and cholinergic inputs on target organs, both sympathetic and parasympathetic neurons are expected to be induced. This study aimed to develop a stepwise chemical induction method to induce sympathetic-like and parasympathetic-like ANS neurons. Autonomic specification was achieved through restricting signals inducing sensory or enteric neurogenesis and activating bone morphogenetic protein (BMP) signals. Global mRNA expression analyses after stepwise induction, including single-cell RNA-seq analysis of induced neurons and functional assays revealed that each induced sympathetic-like or parasympathetic-like neuron acquired pharmacological and electrophysiological functional properties with distinct marker expression. Further, we identified selective induction methods using appropriate seeding cell densities and neurotrophic factor concentrations. Neurons were individually induced, facilitating the regulation of the beating rates of hiPSC-derived cardiomyocytes in an antagonistic manner. The induction methods yield specific neuron types, and their influence on various tissues can be studied by co-cultured assays.
N-terminal deletion of Swi3 created by the deletion of a dubious ORF YJL175W mitigates protein burden effect in S. cerevisiae
Authors: Saeki Nozomu , Eguchi Yuichi , Kintaka Reiko , Makanae Koji , Shichino Yuichi , Iwasaki Shintaro , Kanno Manabu , Kimura Nobutada , Moriya Hisao
Published: June 2020

Extreme overproduction of gratuitous proteins can overload cellular protein production resources, leading to growth defects, a phenomenon known as the protein burden/cost effect. Genetic screening in the budding yeast Saccharomyces cerevisiae has isolated several dubious ORFs whose deletions mitigated the protein burden effect, but individual characterization thereof has yet to be delineated. We found that deletion of the YJL175W ORF yielded an N-terminal deletion of Swi3, a subunit of the SWI/SNF chromatin remodeling complex, and partial loss of function of Swi3. The deletion mutant showed a reduction in transcription of genes encoding highly expressed, secreted proteins and an overall reduction in translation. Mutations in the chromatin remodeling complex could thus mitigate the protein burden effect, likely by reallocating residual cellular resources used to overproduce proteins. This cellular state might also be related to cancer cells, as they frequently harbor mutations in the SWI/SNF complex.
Probing the Structural Dynamics of the Catalytic Domain of Human Soluble Guanylate Cyclase
Authors: Khalid Rana Rehan , Maryam Arooma , Sezerman Osman Ugur , Mylonas Efstratios , Siddiqi Abdul Rauf , Kokkinidis Michael
Published: June 2020

In the nitric oxide (NO) signaling pathway, human soluble guanylate cyclase (hsGC) synthesizes cyclic guanosine monophosphate (cGMP); responsible for the regulation of cGMP-specific protein kinases (PKGs) and phosphodiesterases (PDEs). The crystal structure of the inactive hsGC cyclase dimer is known, but there is still a lack of information regarding the substrate-specific internal motions that are essential for the catalytic mechanism of the hsGC. In the current study, the hsGC cyclase heterodimer complexed with guanosine triphosphate (GTP) and cGMP was subjected to molecular dynamics simulations, to investigate the conformational dynamics that have functional implications on the catalytic activity of hsGC. Results revealed that in the GTP-bound complex of the hsGC heterodimer, helix 1 of subunit α (α:h1) moves slightly inwards and comes close to helix 4 of subunit β (β:h4). This conformational change brings loop 2 of subunit β (β:L2) closer to helix 2 of subunit α (α:h2). Likewise, loop 2 of subunit α (α:L2) comes closer to helix 2 of subunit β (β:h2). These structural events stabilize and lock GTP within the closed pocket for cyclization. In the cGMP-bound complex, α:L2 detaches from β:h2 and establishes interactions with β:L2, which results in the loss of global structure compactness. Furthermore, with the release of pyrophosphate, the interaction between α:h1 and β:L2 weakens, abolishing the tight packing of the binding pocket. This study discusses the conformational changes induced by the binding of GTP and cGMP to the hsGC catalytic domain, valuable in designing new therapeutic strategies for the treatment of cardiovascular diseases.
Time-of-Day Effects on Short-Duration Maximal Exercise Performance
Authors: Mirizio Gerardo Gabriel , Nunes Rodolfo Soares Mendes , Vargas Douglas Araujo , Foster Carl , Vieira Elaine
Published: June 2020

Time-of-day dependent fluctuations in exercise performance have been documented across different sports and seem to affect both endurance and resistance modes of exercise. Most of the studies published to date have shown that the performance in short-duration maximal exercises (i.e. less than 1 min - e.g. sprints, jumps, isometric contractions) exhibits diurnal fluctuations, peaking between 16:00 and 20:00 h. However, the time-of-day effects on short duration exercise performance may be minimized by the following factors: (1) short exposures to moderately warm and humid environments; (2) active warm-up protocols; (3) intermittent fasting conditions; (4) warming-up while listening to music; or (5) prolonged periods of training at a specific time of day. This suggests that short-duration maximal exercise performance throughout the day is controlled not only by body temperature, hormone levels, motivation and mood state but also by a versatile circadian system within skeletal muscle. The time of day at which short-duration maximal exercise is conducted represents an important variable for training prescription. However, the literature available to date lacks a specific review on this subject. Therefore, the present review aims to (1) elucidate time-of-day specific effects on short-duration maximal exercise performance and (2) discuss strategies to promote better performance in short-duration maximal exercises at different times of the day.
Screening and functional identification of lncRNAs in antler mesenchymal and cartilage tissues using high-throughput sequencing
Authors: Chen Dan-yang , Jiang Ren-feng , Li Yan-jun , Liu Ming-xiao , Wu Lei , Hu Wei
Published: June 2020

Long non-coding RNA (lncRNA) is a transcription product of the mammalian genome that regulates the development and growth in the body. The present study aimed to analyze the expression dynamics of lncRNA in sika antler mesenchymal and cartilage tissues by high-throughput sequencing. Bioinformatics was applied to predict differentially expressed lncRNAs and target genes and screen lncRNAs and mRNAs related to osteogenic differentiation, cell proliferation, and migration. Finally, the expression of the lncRNAs and target genes were analyzed by qRT-PCR. The results showed that compared to the cartilage tissue, the transcription levels of lncRNA and mRNA, 1212 lncRNAs and 518 mRNAs, in mesenchymal tissue were altered significantly. Thus, a complex interaction network was constructed, and the lncRNA-mRNA interaction network correlation related to osteogenic differentiation, cell proliferation, and migration was analyzed. Among these, the 26 lncRNAs and potential target genes were verified by qRT-PCR, and the results of qRT-PCR were consistent with high-throughput sequencing results. These data indicated that lncRNA promotes the differentiation of deer antler mesenchymal tissue into cartilage tissue by regulating the related osteogenic factors, cell proliferation, and migration-related genes and accelerating the process of deer antler regeneration and development.
High Pressure Quenched Glasses: unique structures and properties
Authors: Dmowski W. , Yoo G. H. , Gierlotka S. , Wang H. , Yokoyama Y. , Park E. S. , Stelmakh S. , Egami T.
Published: June 2020

Zr-based metallic glasses are prepared by quenching supercooled liquid under pressure. These glasses are stable in ambient conditions after decompression. The High Pressure Quenched glasses have a distinct structure and properties. The pair distribution function shows redistribution of the Zr-Zr interatomic distances and their shift towards smaller values. These glasses exhibit higher density, hardness, elastic modulus, and yield stress. Upon heating at ambient pressure, they show volume expansion and distinct relaxation behavior, reaching an equilibrated state above the glass transition. These experimental results are consistent with an idea of pressure-induced low to high density liquid transition in the supercooled melt.
Cold atmospheric pressure plasma: simple and efficient strategy for preparation of poly(2-oxazoline)-based coatings designed for biomedical applications
Authors: Šrámková Petra , Zahoranová Anna , Kelar Jakub , Kelar Tučeková Zlata , Stupavská Monika , Krumpolec Richard , Jurmanová Jana , Kováčik Dušan , Černák Mirko
Published: June 2020

Poly(2-oxazolines) (POx) are an attractive material of choice for biocompatible and bioactive coatings in medical applications. To prepare POx coatings, the plasma polymerization represents a fast and facile approach that is surface-independent. However, unfavorable factors of this method such as using the low-pressure regimes and noble gases, or poor control over the resulting surface chemistry limit its utilization. Here, we propose to overcome these drawbacks by using well-defined POx-based copolymers prepared by living cationic polymerization as a starting material. Chemically inert polytetrafluoroethylene (PTFE) is selected as a substrate due to its beneficial features for medical applications. The deposited POx layer is additionally post-treated by non-equilibrium plasma generated at atmospheric pressure. For this purpose, diffuse coplanar surface barrier discharge (DCSBD) is used as a source of “cold” homogeneous plasma, as it is operating at atmospheric pressure even in ambient air. Prepared POx coatings possess hydrophilic nature with an achieved water contact angle of 60°, which is noticeably lower in comparison to the initial value of 106° for raw PTFE. Moreover, the increased fibroblasts adhesion in comparison to raw PTFE is achieved, and the physical and biological properties of the POx-modified surfaces remain stable for 30 days.
Formation of gigahertz pulse train by chirped terahertz pulses interference
Authors: Liu Xinrui , Melnik Maksim , Zhukova Maria , Oparin Egor , Rodrigues Joel J. P. C. , Tcypkin Anton , Kozlov Sergei
Published: June 2020

The state-of-art broadband THz sources can contribute to the development of short-range 6G communications. This paper has demonstrated the feasibility of forming the controllable sequence of THz subpulses in the temporal domain and the corresponding quasidiscrete spectrum by the interference of two THz pulses with an exponential chirp. Moreover, due to small time delay between these pulses the temporal and spectral structures are similar to each other (so-called “linkage relation”). This will benefit information encoding in the THz range. The calculated metrics for the prototype communication channel based on the proposed method are competitive with existing short-range THz CW channels.
Effect of life stage and pesticide exposure on the gut microbiota of Aedes albopictus and Culex pipiens L
Authors: Juma Elijah O. , Allan Brian F. , Kim Chang-Hyun , Stone Christopher , Dunlap Christopher , Muturi Ephantus J.
Published: June 2020

Pesticides commonly contaminate the aquatic environments inhabited by mosquito juveniles. However, their role in shaping the mosquito microbiota is not well understood. We hypothesized that environmentally relevant concentrations of atrazine, permethrin and malathion will mediate a shift in the mosquito gut bacterial community structure due to their toxic effect on the aquatic bacterial communities, and reduce mosquito gut bacterial diversity by enriching pesticide-degrading bacterial communities over susceptible taxa. Illumina MiSeq sequencing of the V3-V4 hypervariable regions of the 16 S rRNA gene was used to characterize the microbial communities of larval and adult stages of the two mosquito species and the water samples from microcosms treated with each of the pesticides, separately. Bacterial community composition differed by sample type (larval stage vs. adult stage) and water sampling date (day 3 vs. day 7), but not by pesticide treatment. In larval stages, bacterial OTU richness was highest in samples exposed to malathion, intermediate in permethrin, and lowest in controls. Bacterial richness was significantly higher in larval stages compared to adult stages for all treatments. This study provides a primer for future studies evaluating mosquito microbial responses to exposures to chemical pesticides and the possible implications for mosquito ecology.
The kinetics and mechanism of the uranium hydride - water vapour system under ambient conditions
Authors: Banos A. , Scott T. B.
Published: June 2020

This work investigated the reaction of uranium hydride powder with saturated water vapour at 25 °C. Two corrosion experiments were conducted one with deionised water (H2O) and one with deuterated water (D2O). The kinetics of the reaction were measured through gas generation method while concurrent residual gas analysis (RGA) allowed better understanding of the oxidation mechanism governing the system. From the analysis, it was found that the kinetics of the reaction are robust initially, followed by quasi-linear decelerating regime indicative of a ‘shrinking core’ type oxidation behaviour. The extent of the reaction (conversion to UO2) was lower in comparison to other works. The reaction remained incomplete bolstering the case of UH3 persistence in legacy wastes. Through interpretation of the gas analysis data, a mechanism for the uranium hydride water reaction was suggested.