bluuebunny/crossref_metadata_2025 huggingface dataset:
Excess of Ca (and Sc) produced in globular cluster multiple populations: a first census in 77 Galactic globular clusters
Authors: Carretta Eugenio , Bragaglia Angela
Published: November 2020

Multiple stellar populations in globular clusters (GCs) are distinct by their different abundances of light elements. The abundance anti-correlations point towards a nucleosynthesis origin due to high-temperature H burning, but it remains to be assessed which type of stars altered primordial abundances in GCs. In particular, the regime at very high temperature that shapes the variations in potassium as well as calcium and scandium, which has been detected in a few notable cases such as NGC 2419 and NGC 2808, is still poorly explored. We started a systematic search for excess of Ca (and Sc) in GC stars with respect to the level of unmodified field stars. This method has recently been proven to be highly efficient in revealing the outcome of the proton-capture reactions at very high temperatures. Statistically robust evidence of such excess was found in a small number of GCs (NGC 4833, NGC 6715, NGC 6402, NGC 5296, NGC 5824, and NGC 5139/ωCentauri) that join the previously known two clusters. For the first time we show that NGC 4833 is likely to host anti-correlated K and Mg abundances. All these GCs are among the most massive ones in the Galaxy. We found that the fraction of stars with Ca enhancement at 3σabove the field star distribution is a multivariate function of the GC mass and metallicity, as in other manifestations of the multiple population phenomenon in GCs. We argue that these alterations in only a few GCs can be reproduced by two different channels: either a class of ordinary stars, that is common to all GCs, acts only in particular environments, or an on-off mechanism is generated by the occurrence of a peculiar type of stars (or lack of such stars). Hot bottom-burning in asymptotic giant branch stars in the low-metallicity regime is a good candidate for the first class. Alternatively, a metallicity dependence is also expected for supermassive stars, which are predicted to preferentially form in massive GCs.
Irradiation dose affects the composition of organic refractory materials in space
Authors: Urso R. G. , Vuitton V. , Danger G. , Le Sergeant d’Hendecourt L. , Flandinet L. , Djouadi Z. , Mivumbi O. , Orthous-Daunay F. R. , Ruf A. , Vinogradoff V. , Wolters C. , Brunetto R.
Published: November 2020

Context. Near- and mid-infrared observations have revealed the presence of organic refractory materials in the Solar System, in cometary nuclei and on the surface of centaurs, Kuiper-belt and trans-neptunian objects. In these astrophysical environments, organic materials can be formed because of the interaction of frozen volatile compounds with cosmic rays and solar particles, and favoured by thermal processing. The analysis of laboratory analogues of such materials gives information on their properties, complementary to observations.

Aims. We present new experiments to contribute to the understanding of the chemical composition of organic refractory materials in space.

Methods. We bombard frozen water, methanol and ammonia mixtures with 40 keV H+ and we warmed the by-products up to 300 K. The experiments enabled the production of organic residues that we analysed by means of infrared spectroscopy and by very high resolution mass spectrometry to study their chemical composition and their high molecular diversity, including the presence of hexamethylenetetramine and its derivatives.

Results. We find that the accumulated irradiation dose plays a role in determining the composition of the residue.

Conclusions. Based on the laboratory doses, we estimate the astrophysical timescales to be short enough to induce an efficient formation of organic refractory materials at the surface of icy bodies in the outer Solar System.
Collisional ionisation, recombination, and ionisation potential in two-fluid slow-mode shocks: Analytical and numerical results
Authors: Snow B. , Hillier A.
Published: November 2020

Context.Shocks are a universal feature of warm plasma environments, such as the lower solar atmosphere and molecular clouds, which consist of both ionised and neutral species. Including partial ionisation leads to the existence of a finite width for shocks, where the ionised and neutral species decouple and recouple. As such, drift velocities exist within the shock that lead to frictional heating between the two species, in addition to adiabatic temperature changes across the shock. The local temperature enhancements within the shock alter the recombination and ionisation rates and hence change the composition of the plasma.

Aims.We study the role of collisional ionisation and recombination in slow-mode partially ionised shocks. In particular, we incorporate the ionisation potential energy loss and analyse the consequences of having a non-conservative energy equation.

Methods.A semi-analytical approach is used to determine the possible equilibrium shock jumps for a two-fluid model with ionisation, recombination, ionisation potential, and arbitrary heating. Two-fluid numerical simulations are performed using the (PIP) code. Results are compared to the magnetohydrodynamic (MHD) model and the semi-analytic solution.

Results.Accounting for ionisation, recombination, and ionisation potential significantly alters the behaviour of shocks in both substructure and post-shock regions. In particular, for a given temperature, equilibrium can only exist for specific densities due to the radiative losses needing to be balanced by the heating function. A consequence of the ionisation potential is that a compressional shock will lead to a reduction in temperature in the post-shock region, rather than the increase seen for MHD. The numerical simulations pair well with the derived analytic model for shock velocities.

Conclusion.Multi-fluid effects can lead to a significant departure from MHD results. The results in this paper are applicable to a wide range of partially ionised plasmas, including the solar chromosphere and molecular clouds.
L0TP+: the Upgrade of the NA62 Level-0 Trigger Processor
Authors: Ammendola Roberto , Biagioni Andrea , Ciardiello Andrea , Cretaro Paolo , Frezza Ottorino , Lamanna Gianluca , Lo Cicero Francesca , Lonardo Alessandro , Piandani Roberto , Pontisso Luca , Salamon Andrea , Simula Francesco , Soldi Dario , Sozzi Marco , Vicini Piero
Published: November 2020

The L0TP+ initiative is aimed at the upgrade of the FPGA-based Level-0 Trigger Processor (L0TP) of the NA62 experiment at CERN for the post-LS2 data taking, which is expected to happen at 100% of design beam intensity, corresponding to about 3.3 × 1012 protons per pulse on the beryllium target used to produce the kaons beam. Although tests performed at the end of 2018 showed a substantial robustness of the L0TP system also at full beam intensity, there are several reasons to motivate such an upgrade: i) avoid FPGA platform obsolescence, ii) make room for improvements in the firmware design leveraging a more capable FPGA device, iii) add new functionalities, iv) support the 4 beam intensity increase foreseen in future experiment upgrades. We singled out the Xilinx Virtex UltraScale+ VCU118 development board as the ideal platform for the project. L0TP+ seamless integration into the current NA62 TDAQ system and exact matching of L0TP functionalities represent the main requirements and focus of the project; nevertheless, the final design will include additional features, such as a PCIe RDMA engine to enable processing on CPU and GPU accelerators, and the partial reconfiguration of trigger firmware starting from a high level language description (C/C++). The latter capability is enabled by modern High Level Synthesis (HLS) tools, but to what extent this methodology can be applied to perform complex tasks in the L0 trigger, with its stringent latency requirements and the limits imposed by single FPGA resources, is currently being investigated. As a test case for this scenario we considered the online reconstruction of the RICH detector rings on an HLS generated module, using a dedicated primitives data stream with PM hits IDs. Besides, the chosen platform supports the Virtex Ultrascale+ FPGA wide I/O capabilities, allowing for straightforward integration of primitive streams from additional sub-detectors in order to improve the performance of the trigger.
Viscoelastic flows of Maxwell fluids with conservation laws
Authors: Boyaval Sébastien
Published: November 2020

We consider multi-dimensional extensions of Maxwell’s seminal rheological equation for 1D viscoelastic flows. We aim at a causal model for compressible flows, defined by semi-group solutions given initial conditions, and such that perturbations propagate at finite speed. We propose a symmetric hyperbolic system of conservation laws that contains the Upper-Convected Maxwell (UCM) equation as causal model. The system is an extension of polyconvex elastodynamics, with an additional material metric variable that relaxes to model viscous effects. Interestingly, the framework could also cover other rheological equations, depending on the chosen relaxation limit for the material metric variable. We propose to apply the new system to incompressible free-surface gravity flows in the shallow-water regime, when causality is important. The system reduces to a viscoelastic extension of Saint-Venant 2D shallow-water system that is symmetric-hyperbolic and that encompasses our previous viscoelastic extensions of Saint-Venant proposed with F. Bouchut.
Forecasting based energy management of flywheel energy storage system connected to a wind power plant
Authors: Aasim  , Singh S. N. , Mohapatra Abheejeet
Published: November 2020

The active power output of a wind power system needs regulation due to the stochastic nature of wind speed. A flywheel energy storage system (FESS) is a viable option for active power regulation in a wind power plant. An efficient energy management system (EMS) for FESS is required for healthy operation of the overall connected system. A wind speed forecasting based EMS has been proposed in this paper. It utilizes the repeated wavelet transform based ARIMA model for very short-term wind speed forecasting, which has been proven to be better than the methods that exist in the literature. An artificial neural network based model is used to translate the forecasted wind speed to instantaneous wind power output. Considering the initial energy of FESS, an optimization technique has been used to calculate the speed command to be given to FESS for a given energy exchanged with the grid. The proposed control approach extends FESS usability as an energy exchange system for a period of large change in wind speed where the normal control approach saturates the FESS speed. The feasibility of the proposed EMS algorithm has been tested in MATLAB/Simulink.
Early-warning signals for disease activity in patients diagnosed with multiple sclerosis based on keystroke dynamics
Authors: Twose J. , Licitra G. , McConchie H. , Lam K. H. , Killestein J.
Published: November 2020

Within data gathered through passive monitoring of patients with Multiple Sclerosis (MS), there is a clear necessity for improved methodological approaches to match the emergence of continuous, objective, measuring technologies. As most gold standards measure infrequently and require clinician presence, fluctuations in the daily progression are not accounted for. Due to the underlying conditions of homogeneity and stationarity (the main tenets of ergodicity) not being met for the majority of the statistical methods employed in the clinical setting, alternative approaches should be investigated. A solution is to use a non-linear time series analysis approach. Here, Early-Warning Signals (EWS) in the form of critical fluctuations in Keystroke Dynamics (KD), collected using participant’s smartphones, are investigated as indicators for a clinical change in three groups. These are patients with MS and changes in Magnetic Resonance Imaging (MRI), patients with MS but without changes in MRI, and healthy controls (HCs). Here, we report examples of EWS and changes in KD coinciding with clinically relevant changes in outcome measures in both patients with and without differences in the amount of MRI enhancing lesions. We also report no clinically relevant changes in EWS in the HC population. This study is a first promising step toward using EWS to identify periods of instability as measured by a continuous objective measure as a proxy for outcome measures in the field of MS.
Enhanced electrical properties of Nb-doped a-HfO2 dielectric films for MIM capacitors
Authors: Bon Chris Yeajoon , Kim Dami , Lee Kanghyuk , Choi Sungjoon , Park Insung , Yoo Sang-Im
Published: November 2020

We report enhanced electrical properties of metal–insulator–metal (MIM) capacitors consisting of Al (100 nm)/Nb-doped a-HfO2 (∼30 nm)/Pt (100 nm) on a p-type silicon wafer, where Nb-doped amorphous HfO2 (a-HfO2) layers were deposited by radio frequency magnetron sputtering in various low oxygen partial pressures at room temperature. Polycrystalline HfO2 targets with three different Nb contents of 0 mol. %, 6 mol. %, and 10 mol. % were used in this study. Compared with the leakage current of the undoped a-HfO2 film (∼1.1 × 10−8 A cm−2 at 1 V), greatly reduced leakage currents (∼3.7 × 10−10 A cm−2 at 1 V) with no significant alteration in the dielectric constants (∼22) were obtainable from the MIM samples composed of Nb-doped a-HfO2 films, which is attributable to the suppression of oxygen vacancy formation based on the XPS analysis results. The Nb-doped a-HfO2 dielectric thin films also exhibited improved voltage nonlinearity compared to undoped HfO2. These results indicate that Nb-doped a-HfO2 has potential application as a high-κ dielectric material in MIM capacitors.
Magnetic skyrmionium diode with a magnetic anisotropy voltage gating
Authors: Wang Junlin , Xia Jing , Zhang Xichao , Zheng Xiangyu , Li Guanqi , Chen Li , Zhou Yan , Wu Jing , Yin Haihong , Chantrell Roy , Xu Yongbing
Published: November 2020

The magnetic skyrmionium can be seen as a coalition of two magnetic skyrmions with opposite topological charges and has potential applications in next-generation spintronic devices. Here, we report the current-driven dynamics of a skyrmionium in a ferromagnetic nanotrack with the voltage-controlled magnetic anisotropy. The pinning and depinning of a skyrmionium controlled by the voltage gate are investigated. The current-driven skyrmionium can be used to mimic the skyrmionium diode effect in the nanotrack with a voltage gate. We have further studied the skyrmionium dynamics in the nanotrack driven by a magnetic anisotropy gradient in the absence of spin current. The performance of a single wedge-shaped voltage gate at different temperatures is studied. Our results may provide useful guidelines for the design of voltage-controlled and skyrmionium-based spintronic devices.
A vapor–liquid equilibrium induced Lewis number effect in real-gas shear layers: A theoretical study
Authors: Tudisco P. , Menon S.
Published: November 2020

In this work, the relevance of the multi-phase thermodynamic model based on the vapor–liquid equilibrium (VLE) assumption over the single-phase model is discussed. An emphasis on the importance of the non-linear coupling between thermodynamic, transport, and governing equations is given from a macroscopic point of view by analyzing the mixing effects on a spatial mixing layer in real-gas (non-ideal) conditions. The goal is to prove the existence of an important difference between the two thermodynamic models and, therefore, establish the foundations on the effects that VLE induces in a fluid flow. The results indicate that differences in micro-mixing, ultimately changing the vortex dynamics, are directly related to the imbalance between the heat and mass transfer that occurs within the VLE mixing region of a shear layer.
Strain-magneto-optics in CoFe2O4: Magneto-absorption in Voight geometry
Authors: Sukhorukov Yu. P. , Telegin A. V. , Bebenin N. G. , Naumov S. V. , Nossov A. P.
Published: November 2020

The infrared optical, magneto-optical properties of CoFe2O4 single crystals are considered. The magneto-absorption of natural light in the infrared spectral range in CoFe2O4 spinel is studied in the Voight experimental geometry. This magneto-optical effect is very high and associates with a change in the fundamental absorption edge and impurity absorption bands under a magnetic field. The magneto-absorption strongly depending on both the magnitude and the orientation of the magnetic field relative to the crystallographic axes of the crystal is presented in this paper. The contribution of magnetostriction to the magnetic anisotropy constant of the CoFe2O4 crystal is shown to be abnormally large. The clear connection between magneto-absorption of light in the infrared spectral range and magnetostriction of the CoFe2O4 spinel is established.
Characterization of ferroelectric domain walls by scanning electron microscopy
Authors: Hunnestad K. A. , Roede E. D. , van Helvoort A. T. J. , Meier D.
Published: November 2020

Ferroelectric domain walls are a completely new type of functional interface, which have the potential to revolutionize nanotechnology. In addition to the emergent phenomena at domain walls, they are spatially mobile and can be injected, positioned, and deleted on demand, giving a new degree of flexibility that is not available at conventional interfaces. Progress in the field is closely linked to the development of modern microscopy methods, which are essential for studying their physical properties at the nanoscale. In this article, we discuss scanning electron microscopy (SEM) as a powerful and highly flexible imaging technique for scale-bridging studies on domain walls, continuously covering nano- to mesoscopic length scales. We review seminal SEM experiments on ferroelectric domains and domain walls, provide practical information on how to visualize them in modern SEMs, and provide a comprehensive overview of the models that have been proposed to explain the contrast formation in SEM. Going beyond basic imaging experiments, recent examples for nano-structuring and correlated microscopy work on ferroelectric domain walls are presented. Other techniques, such as 3D atom probe tomography, are particularly promising and may be combined with SEM in the future to investigate individual domain walls, providing new opportunities for tackling the complex nanoscale physics and defect chemistry at ferroelectric domain walls.
Correction and improvement of a widely used droplet–droplet collision outcome model
Authors: Suo Shaoyi , Jia Ming
Published: November 2020

The widely used droplet–droplet collision outcome model distinguishing stretching separation (SS) and fast coalescence (FC) (named SS/FC model) proposed by Jiang et al. [J. Fluid Mech. 234, 171 (1992)] is corrected and improved in this study. By re-deriving the momentum conservation, the correct mathematical expression of the tangential velocity along the sliding direction is obtained. Moreover, to reduce the uncertainties of model applications, the model is improved by expressing the constants as a function of the Ohnesorge number and droplet size ratio. The validation results demonstrate the effectiveness of the improved SS/FC model.
Asymptotic properties of mixing length closures for turbulent pipe flow
Authors: Kollmann W.
Published: November 2020

Turbulence is investigated as the Reynolds number approaches infinity for the flow of an incompressible fluid through straight pipes with a circular cross section under the assumptions that the continuum hypothesis holds, the pipe wall is smooth, and the mixing length closure constructed by Cantwell [“A universal velocity profile for smooth wall pipe flow,” J. Fluid Mech. 878, 834–874 (2019)] is sufficiently accurate to allow the extrapolation to Reynolds numbers beyond the range of the Princeton superpipe data used as a foundation for the closure model. Two sets of scales are introduced to set up two sets of dimensionless equations and two Reynolds numbers for the near wall region (Re, inner scaling) and the center part of the pipe flow (Rτ, outer scaling). It is shown analytically that the turbulent flow asymptotically approaches a two-layer structure: The core of the pipe flow becomes uniform with constant mean velocity and zero shear stress in the outer scaling and the near wall region (inner scaling) with the mean velocity satisfying the law of the wall and non-zero shear stress. The core part of the flow pushes, as Rτ → ∞, the near wall layer to the boundary restricting it to a cylindrical subdomain with zero volume.
Introduction
Authors: Li Mingheng
Published: November 2020

This chapter presents current status of desalination, reverse osmosis, spiral wound membrane, and general guidelines and procedures of reverse osmosis system design. An example of brackish groundwater desalting facility in Southern California - Chino I Desalter, is used to illustrate how a drinking water desalination plant is designed and operated. A brief overview is also given for the Carlsbad seawater desalination plant. Systematic methods for process analysis, design and optimization are introduced at the end of the chapter.
Systematic Analysis and Optimization of Pressure Retarded Osmosis for Power Generation
Authors: Li Mingheng
Published: November 2020

This chapter focuses on model-based analysis and optimization of pressure retarded osmosis (PRO) for power generation. The effects of membrane properties (hydraulic permeability, mass transfer characteristics), design conditions (inlet osmotic pressures, inlet flows and membrane area) and operating condition (applied pressure) on power density and efficiency are systematically investigated. A dimensionless design parameter = ALp_D0/Q0, originally developed in analysis and optimization of reverse osmosis, is used to quantify the effect of dilution in draw solution as water permeates through membrane. An optimization method is developed to maximize PRO performance. It is shown that dilution and concentration polarization significantly reduce the maximum power density, and the optimal _P shifts away from __0/2. Moreover, power density and efficiency follow opposite trends when varying process conditions including draw solution flow rate and membrane area. Enhancing membrane properties is crucial to improve the economic feasibility of PRO.
Transcriptome-based design of antisense inhibitors potentiates carbapenem efficacy in CRE
Escherichia coli
Authors: Aunins Thomas R. , Erickson Keesha E. , Chatterjee Anushree
Published: November 2020

Significance

Carbapenem resistance has become steadily more common in recent decades, and its prevalence in
Enterobacteriaceae
has been marked as an urgent antibiotic priority by both the World Health Organization and the US Centers for Disease Control and Prevention. In this paper, we use RNA sequencing to explore resistance development and engineer peptide nucleic acids (PNA) for bacterial growth inhibition. Our results mark the use of transcriptomics for the design of antibiotic PNA and demonstrate that this method of PNA design can be equally or more effective than standard genome-based design. Furthermore, we identify three genes that may point to antibiotic targets and two genes that offer clues about how
Enterobacteriaceae
acquire carbapenem resistance.
Solar geoengineering may not prevent strong warming from direct effects of CO
2
on stratocumulus cloud cover
Authors: Schneider Tapio , Kaul Colleen M. , Pressel Kyle G.
Published: November 2020

Significance

Solar geoengineering that manipulates the amount of sunlight Earth absorbs is increasingly discussed as an option to counter global warming. However, we demonstrate that solar geoengineering is not a fail-safe option to prevent global warming because it does not mitigate risks to the climate system that arise from direct effects of greenhouse gases on cloud cover. High-resolution simulations of stratocumulus clouds show that clouds thin as greenhouse gases build up, even when warming is modest. In a scenario of solar geoengineering that is sustained for more than a century, this can eventually lead to breakup of the clouds, triggering strong (5°C), and possibly difficult to reverse, global warming, despite the solar geoengineering.
Consequences of seafood mislabeling for marine populations and fisheries management
Authors: Kroetz Kailin , Luque Gloria M. , Gephart Jessica A. , Jardine Sunny L. , Lee Patrick , Chicojay Moore Katrina , Cole Cassandra , Steinkruger Andrew , Donlan C. Josh
Published: November 2020

Significance

The consumption of an important food source, seafood, has increased over the past half century. It is now the most globally traded food commodity and its supply chains are often complex and opaque. Contemporaneous with the growth of overall production, evidence of seafood product mislabeling has become ubiquitous. We show that enabling conditions exist for mislabeling to generate negative impacts on marine populations and to support consumption of products from poorly managed fisheries. More holistic approaches that include consumer and industry engagement, well-designed and targeted testing, and regulatory traceability programs could reduce seafood mislabeling and improve transparency related to impacts of seafood product consumption.
Hidden symmetries generate rigid folding mechanisms in periodic origami
Authors: McInerney James , Chen Bryan Gin-ge , Theran Louis , Santangelo Christian D. , Rocklin D. Zeb
Published: November 2020

Significance

The traditional approach to designing origami metamaterials uses particular, highly symmetric crease patterns to generate folding motions for reconfigurability. We instead consider origami sheets with periodic but otherwise generic, asymmetric triangular faces and show they exhibit nonlinear folding motions which transform sheets through two-dimensional families of cylindrical configurations, with the addition of quadrilateral faces restricting sheets to one-dimensional subsets of configurations. This leads to a topological class of mechanical modes, preventing origami from exhibiting exponentially localized floppy modes observed in other systems. These results do not depend on scale or material and hence have applications extending to architecture and robotics, but particularly to the nanoscale, where limited control over fold patterns can constrain traditional techniques.
Lack of adipocyte purinergic P2Y
6
receptor greatly improves whole body glucose homeostasis
Authors: Jain Shanu , Pydi Sai P. , Toti Kiran S. , Robaye Bernard , Idzko Marco , Gavrilova Oksana , Wess Jürgen , Jacobson Kenneth A.
Published: November 2020

Significance

The prevalence of obesity and type 2 diabetes (T2D) has increased worldwide. Obesity is correlated with unfavorable adipose tissue modifications that lead to metabolic dysregulation. Here, we show that P2Y
6
R deficiency in adipocytes protects from diet-induced obesity due to enhanced energy expenditure, reduced inflammation, and white adipose tissue browning. Further, adipocytes lacking P2Y
6
R show reduced JNK expression and activity, contributing to the improved phenotype. This proof-of-concept study strongly suggests that P2Y
6
R antagonists may be beneficial for the treatment of obesity and T2D.
Thymus-derived B cell clones persist in the circulation after thymectomy in myasthenia gravis
Authors: Jiang Ruoyi , Hoehn Kenneth B. , Lee Casey S. , Pham Minh C. , Homer Robert J. , Detterbeck Frank C. , Aban Inmaculada , Jacobson Leslie , Vincent Angela , Nowak Richard J. , Kaminski Henry J. , Kleinstein Steven H. , O’Connor Kevin C.
Published: November 2020

Significance

Myasthenia gravis is caused by autoantibodies, which target postsynaptic proteins, primarily the acetylcholine receptor, that inhibit neuromuscular signaling. The myasthenia gravis thymus can serve as a reservoir of acetylcholine receptor-specific autoantibody-producing B cells. Thus, thymectomy is provided as a treatment. However, many patients fail to improve; the causes of poor responses are not understood. This investigation demonstrated that disease-associated B cell clones mature in the thymus before emigrating to the circulation. These B cell clones are present in the circulation after thymectomy and their persistence correlated with less favorable changes in clinical symptoms after thymectomy. This investigation provides mechanistic insight into the immunopathology associated with a diminished clinical response to thymectomy.
FMRP links optimal codons to mRNA stability in neurons
Authors: Shu Huan , Donnard Elisa , Liu Botao , Jung Suna , Wang Ruijia , Richter Joel D.
Published: November 2020

Significance

Fragile X syndrome (FXS), the most prevalent monogenic form of autism, is caused by the loss of FMRP, an RNA binding protein. In the absence of FMRP, translation is dysregulated, but restoration of translational homeostasis rescues the syndrome and thus could suggest new treatments for the disorder. Using ribosome profiling and RNA metabolic profiling, we show that, in the FMRP-deficient mouse brain, there are few specific translational disturbances. Instead, there is widespread imbalance of RNA levels. This imbalance is caused by destabilization of the FMRP targets and other mRNAs based on codon optimality. Rebalancing the transcriptome may therefore be a key to correcting syndrome-related pathophysiologies. This study establishes a role for FMRP in linking codon optimality to RNA stability.
Hyperchromatic structural color for perceptually enhanced sensing by the naked eye
Authors: Talukdar Tahmid H. , McCoy Bria , Timmins Sarah K. , Khan Taufiquar , Ryckman Judson D.
Published: November 2020

Significance

Modern scientific instrumentation and sensors are often bulky, expensive, and/or cumbersome to operate. Colorimetric sensors on the other hand offer a promising solution to these problems, as they can be analyzed with high spatiotemporal resolution by digital cameras or the naked eye. However, the performance of colorimetric sensors is typically inferior to the bulky/expensive alternatives as it can be difficult to convert small input stimulus variations into a large color response. This work introduces a means to address and overcome this problem and opens the door to types of high-performance colorimetric sensors, which are competitive with and/or offer greater functionality than the bulky/expensive alternatives.
Swimming microorganisms acquire optimal efficiency with multiple cilia
Authors: Omori Toshihiro , Ito Hiroaki , Ishikawa Takuji
Published: November 2020

Significance

In this study, we clarified energetics of microbial locomotion by computing flow around a spherical swimmer covered with cilia. We showed a scaling law for microbial dynamics and revealed that microorganisms can swim optimally and enlarge their bodies by making multiple cilia. The optimal density of cilia was independent of the body size. Our estimated optimal density of cilia corresponded to those of actual microorganisms, including species of ciliates and microalgae. These results will help us to understand the mechanistic benefits of multiple cilia and open up an area of research that integrates fluid mechanics, biophysics, and microbiology.
Mercury isotopes identify near-surface marine mercury in deep-sea trench biota
Authors: Blum Joel D. , Drazen Jeffrey C. , Johnson Marcus W. , Popp Brian N. , Motta Laura C. , Jamieson Alan J.
Published: November 2020

Significance

Mercury is a globally distributed neurotoxic pollutant that can be biomagnified in marine fish to levels that are harmful for consumption by humans and other animals. The degree to which mercury has infiltrated the oceans yields important information on the biogeochemistry of mercury and its expected effects on fisheries during changing mercury emissions scenarios. Mercury isotope measurement of biota from deep-sea trenches was used to demonstrate that surface-ocean-derived mercury has infiltrated the deepest locations in the oceans. It was found that when fish living in the surface ocean die and their carcasses sink (along with marine particles), they transfer large amounts of mercury to the trench foodwebs leading to high concentrations of mercury in trench biota.
The effect of tethering on the clearance rate of suspension-feeding plankton
Authors: Andersen Anders , Kiørboe Thomas
Published: November 2020

Many planktonic suspension feeders are attached to particles or tethered by gravity when feeding. It is commonly accepted that the feeding flows of tethered suspension feeders are stronger than those of their freely swimming counterparts. However, recent flow simulations indicate the opposite, and the cause of the opposing conclusions is not clear. To explore the effect of tethering on suspension feeding, we use a low-Reynolds-number flow model. We find that it is favorable to be freely swimming instead of tethered since the resulting feeding flow past the cell body is stronger, leading to a higher clearance rate. Our result underscores the significance of the near-field flow in shaping planktonic feeding modes, and it suggests that organisms tether for reasons that are not directly fluid dynamical (e.g., to stay near surfaces where the concentration of bacterial prey is high).
Glutaric acid production by systems metabolic engineering of an
l
-lysine–overproducing
Corynebacterium glutamicum
Authors: Han Taehee , Kim Gi Bae , Lee Sang Yup
Published: November 2020

Significance

Glutaric acid is an important dicarboxylic acid used in the synthesis of commercial polymers. Here we report metabolic engineering of an
l
-lysine–overproducing
Corynebacterium glutamicum
strain for the high-level production of glutaric acid. The glutaric acid biosynthesis pathway was established in
C. glutamicum
by optimally expressing the genes encoding key enzymes from
Pseudomonas putida
and
C. glutamicum
for the efficient conversion of
l-
lysine to glutaric acid. Further metabolic engineering and overexpression of a newly discovered glutaric acid exporter gene resulted in the production of 105.3 g/L of glutaric acid without byproducts from glucose. The metabolic engineering strategies described here will be useful for developing microbial strains for the bio-based production of other chemicals in addition to glutaric acid.
A microbial metabolite synergizes with endogenous serotonin to triggerC. elegansreproductive behavior
Authors: Chen Yen-Chih , Seyedsayamdost Mohammad R. , Ringstad Niels
Published: November 2020

Significance

Neurochemical signaling pathways are important therapeutic targets for the treatment of brain disorders, including complex psychiatric disorders that affect poorly understood cognitive and affective mechanisms. Despite a pressing need for improved psychopharmacology, it has proved difficult to discover new types of small molecules that target neurochemical signaling. We have used a behavior-based screen to identify natural products that strongly and specifically interact with serotonin signaling in the nervous system of the nematodeCaenorhabditis elegans. This approach identified a microbial metabolite that is structurally unrelated to known activators of serotonin signaling. Our study suggests that microbe-derived small molecules can be a rich source of novel neuroactive compounds.
Biophysical analysis of the structural evolution of substrate specificity in RuBisCO
Authors: Poudel Saroj , Pike Douglas H. , Raanan Hagai , Mancini Joshua A. , Nanda Vikas , Rickaby Rosalind E. M. , Falkowski Paul G.
Published: November 2020

Significance

RuBisCO, the most abundant enzyme on Earth, catalyzes the fixation of CO
2
to form an organic acid. It does not clearly discriminate between CO
2
and O
2
. Reaction with the former leads to the productive formation of organic carbon; reaction with the latter leads to a metabolically futile, but energetically costly pathway. To elucidate how the enzyme discriminates between CO
2
and O
2
, we used computational approaches to identify regions around the active site that play key roles in differentiating the substrates. Our research reveals that the specificity of the enzyme is strongly correlated with the structure of the binding channel in the active site. This work poses a potential pathway to genetically engineer more efficient RuBisCOs.
Evidence accumulation for value computation in the prefrontal cortex during decision making
Authors: Lin Zhongqiao , Nie Chechang , Zhang Yuanfeng , Chen Yang , Yang Tianming
Published: November 2020

Significance

Decision making involves the evaluation of the options, and the current popular theory puts the orbitofrontal cortex (OFC) in a central role in this process. However, by using a sophisticated task design in which the decision making requires both evidence accumulation over time and a stimulus-to-action transformation, we found that the OFC neuronal activity reflected neither. Both processes were instead represented in the dorsolateral prefrontal cortex (DLPFC), and the stimulus-to-action transformation occurred before the evidence accumulation. Our study argued for a more limited role of the OFC in value-based decision making than previously proposed and indicated how the OFC and the DLPFC may work together to compute value during decision making.
Single-cell lineage mapping of a diverse virus-specific naive CD4 T cell repertoire
Authors: Khatun Achia , Kasmani Moujtaba Y. , Zander Ryan , Schauder David M. , Snook Jeremy P. , Shen Jian , Wu Xiaopeng , Burns Robert , Chen Yi-Guang , Lin Chien-Wei , Williams Matthew A. , Cui Weiguo
Published: November 2020

Tracking how individual naive T cells from a natural TCR repertoire clonally expand, differentiate, and make lineage choices in response to an infection has not previously been possible. Here, using single-cell sequencing technology to identify clones by their unique TCR sequences, we were able to trace the clonal expansion, differentiation trajectory, and lineage commitment of individual virus-specific CD4 T cells during an acute lymphocytic choriomeningitis virus (LCMV) infection. Notably, we found previously unappreciated clonal diversity and cellular heterogeneity among virus-specific helper T cells. Interestingly, although most naive CD4 T cells gave rise to multiple lineages at the clonal level, ∼28% of naive cells exhibited a preferred lineage choice toward either Th1 or TFH cells. Mechanistically, we found that TCR structure, in particular the CDR3 motif of the TCR α chain, skewed lineage decisions toward the TFH cell fate.
Fly-ash Enriched Earthen Un-Burnt Bricks for Low-cost Housing
Authors: Jena Joygopal , Sahoo Chinmayanada , Singh Kalyani S.
Published: November 2020

In spite of various major steps taken by the Governments, housing problem in rural India is becoming bad to worse due to population explosion and their low income. Various low-cost housing schemes has been floated through use of cheaper construction materials. Therefore, development of new cheaper materials has become need of the day. This can be possible by production of new materials produced from various by-products or wastes justifying the slogan converting ‘Wastes into Wealth’. Fly ash, a coal combustion by-product available in power plants is one such material available in plenty in our surroundings those are posing problem to the environment. Presently, these are utilised by mixing various cementitious materials in production of bricks, those are substituting conventional bricks, for their cost effectiveness. But, the extreme poor people of tribal areas are deprived of using these bricks in their houses due to non-availability and financial constraints. Most of tribal houses in KBK districts of Odisha, Eastern and Central rural of Chhattisgarh, some parts of Jharkhand, Bihar and West Bengal are made of walls with twigs plastered with mud and Nauria tiled roofing. To bridge the gap a new product ‘Fly ash Enriched Earthen Unburnt brick’ has been proposed. Necessary laboratory tests for the proposed product has been carried and their suitability is presented in this paper. Poor people who can’t afford for standard bricks for their houses, this can be an alternate cheaper solution for them.
A Review on the Bacterial Concrete Properties
Authors: Jena Shradha , Basa Bidyadhar , Chandra Panda Kishor
Published: November 2020

A very commonly used and widespread building material, concrete has various limits of using it, one of which is crack formation. Formation of larger cracks let water and CO2 enter into the building materials which in turn react along with other chemicals causing an eye catching reduction in strength and durability. If immediate remedies are not taken to heal the cracks, it might lead to more serious problems like bigger cracks, more leakage of water, reduced strength, costlier to repair. Hence the best way to deal with such situation and to heal concrete even before it starts spreading is self-healing concrete. Self-healing concrete is the most recent and most current cutting-edge technological development in the field of building materials. Self-healing bacteria has the capacity to heal itself. The underlying principle of this mechanism is forming calcium carbonate precipitate with the help of bacteria as a blocking material for cracks. This new and innovative introduction of bacteria into the building materials show new light on production of sustainable, durable, strong concrete having prolonged life period. Due to the introduction of bacteria in concrete, the name becomes bacterial concrete. Bacterial / microbial concrete is pollution free, economic and cost effective. This paper aims at defining bacterial concrete, mechanism and its effects on concrete properties.
Geosynthetic as Sustainable Materials for Earthquake resistant of Masonry Structures
Authors: Ali Khan Hasim , Behera Biplab , Prasad Nanda Radhikesh
Published: November 2020

When exposed to simultaneous in-plane and out-of-plane behaviour generated by earthquakes or high wind pressure, unreinforced masonry (URM) walls are vulnerable to failure. The paper presents the performance of brick masonry panels using non-woven geotextile in-plane shear and out-of-plane bending experimentally tested. The panels were reinforced with a diagonal geometric pattern on both sides. From the laboratory assessment, it was determined that geosynthetic enhancement significantly improved the capacity of load carrying, displacement capacity, bending moment, stiffness, diagonal shear, in-plane shear, and flexural strength with higher performance for both cases in the case of the cross pattern. In contrast to the un-strengthened panel, experimental findings have demonstrated a less fragile behaviour. Geosynthetics can therefore be preferably suited for strengthening the brick masonry panel in order to defend brick constructions in seismic populated places.
Thermal Power Plant Waste By-product and Its Utility in Concrete
Authors: Bhagat S. R. , Mahajan Lomesh
Published: November 2020

Nearly 117 coal based thermal power station has working conditions in India. About 71% (169 x 103 MW) electricity is generated from four Indian regions i.e. Western, Northern, Eastern, and Southern. All these thermal power plant has produces by-product after burning coal as an energy inputs. The by-product obtained in the form of fine ash which has been known as fly ash and bottom ash. These by-products directly dump on the nearby area or thrown into low lying areas. The utility of these finer materials has proven a feasible substance in the concrete constituents. The paper presents possible advantages to incorporate it into concrete. Fly ash, bottom ash and pond ash has potential to act as a binding and filler agent in concrete.
Mechanical Properties of Concrete with Sintered Fly Ash Aggregate as Substitute of Natural Fine Aggregate
Authors: Basa Bidyadhar , Pradhan Nibedita , Priyadarshini Parhi Lipsita
Published: November 2020

Attempts have been made from time long to develop construction materials which should be strong, durable and simultaneously of light weight. In an attempt to reduce the self-weight of the structural concrete, light weight aggregates are being used and implemented. Fly ash is a waste material of coal based thermal power plants. Presently, fly ash is being used in construction industries in different ways. Sintered fly ash aggregates when used as a substitute for natural aggregates benefits the preservation of natural aggregates as well as the utilization of fly ash which poses a great environmental problem for its disposal. Simultaneously, it also reduces the cost of concrete. In the present investigation, sintered fly ash light weight aggregates have been used as a partial replacement of natural sand as fine aggregate in concrete. Varying percentages of natural fine aggregate have been replaced by sintered fly ash light weight aggregates. Experimental investigations have been carried out to study the mechanical properties related to the strength of concrete, namely, compressive strength, split tensile strength and flexural strength with sintered fly ash aggregate as fine aggregate substitute in concrete. In all mixes, silica fume have been used in conjunction with the binder material consisting of ordinary Portland cement.
Comparative Mechanical Characterization of M30 Concrete Grade by Fractional Replacement of Portland Pozzolana Cement with Industrial Waste Using CoCoSo and CODAS Methods
Authors: Kumar Bagal Dilip , Naik Bibekananda , Parida Biswajit , Barua Abhishek , Jeet Siddharth , Kumar Singh Sangam , Kumar Pattanaik Ajit
Published: November 2020

Since last few years, marble has been deliberated as some of the utmost significant embellished constructing resources. Marble Powder (MP) and Fly Ash (FA) are nearly those materials, which creates health hazards and pollutes the environment. This present study targets to investigate the effect of marble powder and fly ash as fractional replacement of cement respectively in different concrete mixes. The M30 grade of concrete was chosen with a continual w/c ratio 0.43 where fractional replacement of Portland Pozzolana Cement with Marble Powder and Fly Ash is done in different proportion. After preparing the samples according to Taguchi’s method orthogonal array, the mechanical characterizations are performed. Hardened concrete tests such as compressive strength, split tensile strength and flexural strength test have been piloted to appraise the mechanical properties of concrete. Two current multi-response optimization techniques were used i.e. Combinative Distance-based Assessment (CODAS) and Combined Compromise Solution (CoCoSo) method for optimization of process parameters. In order to outline comparative consequence of measured criteria a pairwise comparison matrix was used. The results of all tests were analyzed, comparison has done among concrete mixes and the conclusion is drawn.
Mechanical Characterization of Hybrid Polymer SiC Nano Composite Using Hybrid RSM-MOORA-Whale Optimization Algorithm
Authors: Kumar Bagal Dilip , Parida Biswajit , Barua Abhishek , Naik Bibekananda , Jeet Siddharth , Kumar Singh Sangam , Kumar Pattanaik Ajit
Published: November 2020

Colossal materials do not provide a wide range of applications due to their mechanical property limitations. Fiber reinforced polymer composites are now considered as an important class of engineering materials. The processing and mechanical characterization of a new class of multi-phase composites consisting of polyester resin reinforced with jute-glass-silk fiber. This research investigation deals with mechanical properties of hybrid polymer composite. Woven palm fiber, teak wood dust and SiC Nano particles have been used for fabrication of the composites. Experiments have been planned as per Response Surface Method. After preparing the composite material by hand layup technique and then the mechanical characterizations are performed. Multi-response optimization has been carried out using Multi objective optimization on the basis of the ratio analysis method (MOORA) and Whale Optimization Algorithm. Optimal results have been verified through confirmatory experiments. Based on the experimental observations density, flexural and Ultimate Tensile Strength, it is concluded that teak wood powder influences the mechanical properties more than that of other two reinforcements but Nano particle filled composites shows better properties.