bluuebunny/crossref_metadata_2025 huggingface dataset:
Pattern preservation during the decay and growth of localized wave packet in two-dimensional channel flow
Authors: Zhang Linsen , Tao Jianjun
Published: June 2022

In this paper, the decay and growth of localized wave packet (LWP) in a two-dimensional plane-Poiseuille flow are studied numerically and theoretically. When the Reynolds number (Re) is less than a critical value Rec, the disturbance kinetic energy Ek of LWP decreases monotonically with time and experiences three decay periods, i.e., the initial and the final steep descent periods and the middle plateau period. Higher initial Ek of a decaying LWP corresponds to longer lifetime. According to the simulations, the lifetime scales as (Rec−Re)−1/2, indicating a divergence of lifetime as Re approaches Rec, a phenomenon known as “critical slowing-down.” By proposing a pattern preservation approximation, i.e., the integral kinematic properties (e.g., the disturbance enstrophy) of an evolving LWP are independent of Re and single valued functions of Ek, the disturbance kinetic energy equation can be transformed into the classical differential equation for saddle-node bifurcation, by which the lifetimes of decaying LWPs can be derived, supporting the −1/2 scaling law. Furthermore, by applying the pattern preservation approximation and the integral kinematic properties obtained as Re<Rec, the Reynolds number and the corresponding Ek of the whole lower branch, the turning point, and the upper-branch LWPs with Ek<0.15 are predicted successfully with the disturbance kinetic energy equation, indicating that the pattern preservation is an intrinsic feature of this localized transitional structure.
On loading fluctuations induced by energetic large-scale motions for horizontal axis wind turbines
Authors: Ahmadi Mohammad H. B. , Yang Zhiyin
Published: June 2022

The interaction of horizontal axis wind turbines (HAWTs) and large-scale energetic flows is not fully understood. The unsteady flow approaching turbines could result in highly unsteady blade forces and root bending moments (RBMs) which would have a strong influence on the turbine's operational life span, especially for large-scale wind turbines. To provide a better understanding of this interaction, numerical simulations of a three-bladed HAWT with a cylinder located at its upstream to produce energetic motions of varying scale relative to the turbine size have been carried out to examine the temporary variations of the turbine root bending moments. The predicted spectra reveal that the energetic large-scale motions produced by the cylinder strongly interact with the instantaneous blade forces and, thus, root bending moments. It specifically shows how dominant large-scale motions approaching the turbine significantly influence the spectral characteristics of flapwise and edgewise RBMs in terms of level and trend. The comparison shows that below about half of the blade passage frequency, RBMs spectra correlate well with those of upstream velocity, whereas above this frequency, RBMs spectra are mainly influenced by the turbine rotational frequency. This study also shows that the strong scale-to-scale interaction between the upstream flow and turbine loading reported previously does not appear at high Reynolds numbers in the present study.
Assessing soil quality and their indicators for long-term rice-based cropping systems in hot sub-humid eco-region of India
Authors: Kumar Uttam , Mishra V. N. , Kumar Nirmal , Srivastava L. K. , Tedia K. , Bajpai R. K. , Singh Muneshwar , Mohanty M.
Published: June 2022

Context Rice-based cropping system is a key for food security in the Indian subcontinent. However, the productivity of such systems has declined continuously due to deterioration in soil quality. The present study was carried out to identify key soil quality indicators and to develop indices of soil quality under long-term rice-based cropping systems in the hot sub-humid eco-region (HSE) of India. Methods Surface soil samples were collected from farmers’ field from two soil orders (Vertisols and Inceptisols) and with four long-term rice-based cropping systems: (1) rice-wheat (RW); (2) rice-chickpea (RC); (3) rice-lathyrus (RL); and (4) rice-fallow (RF). A minimum data set (MDS) of 24 soils attributes were screened to identify soil quality indicators using principal components analysis (PCA), and soil quality index (SQI) was determined. Key results The MDS indicators (in descending order of sensitivity) are field capacity (FC) (35.4%) followed by pH (30.5%) > porosity (13.6%) > potentially mineralisable carbon (PMC) (11.8%) > available boron (AB) (8.7%). Soil moisture content under FC was found as the most sensitive indicator affecting soil quality and rice equivalent yields (REY). The SQI of Vertisols (0.83) was significantly higher (P < 0.05) than Inceptisols (0.73). SQI under RC (0.86) cropping systems was significantly higher than RL (0.81), RW (0.76) and RF (0.78) (P < 0.05). Conclusions The inclusion of legumes (chickpea and lathyrus) into cropping systems sustained better soil quality and productivity. Implications SQI is not only useful for assessing soil health but also provides indicators of best-bet management practices for sustaining intensive cultivation.
Repeated‐sprint training in heat and hypoxia: Acute responses to manipulating exercise‐to‐rest ratio
Authors: Dennis Myles C. , Goods Paul S.R. , Binnie Martyn J. , Girard Olivier , Wallman Karen E. , Dawson Brian , Billaut Francois , Peeling Peter
Published: June 2022

The aim of this study was to investigate acute performance and physiological responses to the manipulation of exercise‐to‐rest ratio (E:R) during repeated‐sprint hypoxic training (RSH) in hot conditions. Twelve male team‐sport players completed two experimental sessions at a simulated altitude of ∼3000 m (FIO2 0.144), air temperature of 40°C and relative humidity of 50%. Exercise involved either 3 × 5 × 10‐s (E:R1:2) or 3 × 10 × 5‐s (E:R1:4) maximal cycling sprints interspersed with active recoveries at 120W (20‐s between sprints, 2.5 and 5‐min between sets for E:R1:2 and E:R1:4 respectively). Sessions were matched for overall sprint and total session duration (47.5‐min). Peak and mean power output, and total work were greater in E:R1:4 than E:R1:2 (p < 0.05). Peak core temperature was significantly higher in E:R1:4 than E:R1:2 (38.44 ± 0.33 vs. 38.20 ± 0.35°C, p = 0.028). Muscle deoxygenation magnitude during sprints was greater in E:R1:2 (28.2 ± 1.6 vs. 22.4 ± 4.6%, p < 0.001), while muscle reoxygenation did not differ between conditions (p > 0.05). These results indicate E:R1:4 increased mechanical power output and core temperature compared to E:R1:2. Both protocols had different effects on measures of muscle oxygenation, with E:R1:2 generating greater muscle oxygen extraction and E:R1:4 producing more muscle oxygenation flux, which are both important signals for peripheral adaptation. We conclude that the E:R manipulation during RSH in the heat might be used to target different physiological and performance outcomes, with these findings forming a strong base for future mechanistic investigation.
Novel and Self-Consistency Analysis of the QCD Running Coupling α
s(Q) in Both the Perturbative and Nonperturbative Domains
Authors: Yu Qing , Zhou Hua , Huang Xu-Dong , Shen Jian-Ming , Wu Xing-Gang
Published: June 2022

The quantum chromodynamics (QCD) coupling α
s is the most important parameter for achieving precise QCD predictions. By using the well measured effective coupling

α
s

g
1

(
Q
)

defined from the Bjorken sum rules as a basis, we suggest a novel self-consistency way to fix the α
s at all scales: The QCD light-front holographic model is adopted for its infrared behavior, and the fixed-order pQCD prediction under the principle of maximum conformality (PMC) is used for its high-energy behavior. Using the PMC scheme-and-scale independent perturbative series, and by transforming it into the one under the physical V scheme, we observe that a precise α
s running behavior in both the perturbative and nonperturbative domains with a smooth transition from small to large scales can be achieved.
Online learning mediated by social teaching platforms: an experience from a flipped undergraduate physics course in renewable energies
Authors: Tuveri Matteo , Zurru Alessia , Fadda Daniela , Saba Michele
Published: June 2022

Active learning strategies and information technology-based pedagogies are perceived as beneficial and their use and development in academic courses is fast increasing. Faculties can use them to design courses that are challenging and fresher, creative, and meaningful for students, to meet students’ needs and to promote the learning of contents in a social environment, fostering cooperation and the exchange of ideas among peers. Among the active learning strategies recently developed, the peer-instruction and the flipped classroom are prominent in this field. It has been shown that these practices help students in their understanding of contents and consequently in reaching better results in final exam scores. The Covid-19 pandemic in 2020 and 2021 has forced classes in many academic institutions to move to remote teaching under emergency conditions and has deprived students of much of their social interactions. We show here an experience on applying online learning mediated by social teaching platforms and flipped classroom concepts to an undergraduate course on renewable energies provided amid the Covid-19 pandemic at the Physics Department of the University of Cagliari (Italy) in 2020. The constraints of forced distance learning have been turned into an opportunity to test an alternate course format in a complete online environment. An analysis on students’ feedback about our learning method has been performed by a post-diagnostic satisfaction questionnaire, indicating an overall positive effects of active learning strategies in the students’ learning experience. The analysis of their achievements during the course provides confirmation for the positive outcome and shows that the flipped classroom architecture is as robust as the traditional methods when facing the constraints of remote learning.
The Feynman paradox and hidden momentum
Authors: Jiménez J L , Campos I , Roa-Neri J A E
Published: June 2022

Though it is generally accepted that electromagnetic radiation fields possess energy and linear and angular momentum, the adscription of these properties to static and quasi-static fields rises some doubts. Some authors consider that in electrostatics the concept of field is superfluous, or that action-at-a-distance and field are equivalent views. However, the interpretation of Poynting’s vector divided by c
2 as a momentum density is consistent and necessary for the conservation laws to hold, even in static conditions. The Feynman paradox exhibits the necessity of assigning linear and angular momentum to static and quasi-static fields, showing in this way that the points of view of action-at-a-distance and field are not equivalent. In the present work we do not intend to present a revision of the literature on this subject, but to show that the concept of hidden momentum is useful to solve the paradox, and we show that it is part of a momentum balance equation derived directly from the macroscopic Maxwell equations. Another consequence of this balance equation is that, in static conditions, the momentum associated to Poynting’s vector equals the hidden momentum and cancels it. Graduate students and researchers interested in conceptual problems of electromagnetism will find a firm foundation of the concept of hidden momentum and an alternative view of the paradox.
Measuring the refractive index of a transparent sphere from the primary and secondary rainbows
Authors: Ma Yao , Lin Hao-Chen , Shi Wen-Jia , Zhang Qin , Qu Guang-Hui , Pang Mi
Published: June 2022

We propose a method to obtain the refractive index of a transparent sphere from the fascinating phenomena of rainbows, which can be used as an interesting subject in the experimental courses of primary optics for undergraduate or high school students. The primary and secondary rainbows are reproduced on white walls and screens in the classroom with the sun and water drops replaced by the LED flashlight and K9 glass (one type of borosilicate glass) sphere respectively. The locations of the primary and secondary rainbows on the screen are measured, with the locations of the screen and sphere changed. By fitting the multiple measurements to the theoretical result using the least square method, the refractive index of the glass sphere, as an unknown parameter in the fitting process, is obtained. For both the primary and secondary rainbows, the locations of the red, yellow and purple bows are measured independently. Repetitive measurements give very stable and accurate output with the standard deviation ratio as low as 10−4 and the relative error all around 0.1% compared to the result obtained from special instruments in the literature. The fascinating phenomena and precise measurements enable this method to fully deepen the students’ understanding of the law of refraction and the application of the least square method.
Non-faradaic electrochemical impedance spectroscopy analysis of C-MEMS derived bio-modified glassy carbon electrode
Authors: Patel Rhea , Islam Md Saiful , Mandal Naresh , Pramanick Bidhan
Published: June 2022

In this work, we have developed a carbon-microelectromechanical systems derived glassy carbon electrode (GCE) for non-faradaic electrochemical impedance spectroscopy (nf-EIS) measurement to detect electrode interfacial changes upon biomodification. This is carried out using a three-electrode system configuration. The fabricated electrode was electrochemically characterized in phosphate-buffered solution, and then changes in impedance were observed upon bio-modification of the electrode surface. The absence of any labelling molecule and no redox indicators makes the measurement system more straightforward and precise. The investigations were done using a standard deoxyribonucleic acid (DNA) immobilization on the GCE. The surface modification was done using a two-step assembly protocol linking the probe to the carbon electrode and blocking the unwanted sites using a spacer chemical-mercaptohexanol. The results obtained help us to understand the electrical signatures upon bio-modification of electrodes in the presence of a probe and its complementary 50 ng μl−1 DNA target. nf-EIS relies on various microscopic interactions, which occur at the electrode–electrolyte interface system. We are currently working on extending this study to develop a precise, accurate and sensitive sensor to detect bio-molecular interactions occurring on the GCE to detect disease-causing microorganisms in contaminated water samples.
Temperature-dependent breakdown and pre-breakdown conduction of polyethylene terephthalate
Authors: Zhou Jierui , Sotzing Michael , Li Zongze , Wu Chao , Zhou Peinan , Wang Yifei , Cao Yang
Published: June 2022

In this paper, electrical conduction of polyethylene terephthalate (PET) films at ultrahigh fields up to breakdown was experimentally investigated using a specially designed circuitry with a dynamic gain-controlled capacitive current cancellation. The breakdown strength of PET is found stable in the temperature range from 25 °C to 100 °C, while the charge-to-breakdown exhibits a dramatic increase over the same temperature range. Furthermore, a turning point is observed around the glass transition temperature (T
g) of PET for the onset field of the nonlinear conduction. The impact of this secondary transition process in PET on the pre-breakdown conduction is revealed by the Arrhenius analysis, with distinctively different activation energies of 0.70 and 0.22 eV determined for above and below the glass transition temperature, respectively, indicating clearly an increased temperature-dependence of conduction above T
g. Explicit space-charge-limited-current features are extracted for the pre-breakdown conduction above T
g. With exponential trap distribution model, the characteristic temperature of PET films is extracted from the trap-filling region to be 665 K, and the total trap density is determined to be

1.66
×

10

17

 c

m

−
3

. This study unveils the important role that the physical long-chain topological disorder plays in the electronic and dielectric properties of polymeric dielectrics in association with the secondary transition process. Further study holds the promise for better understanding of underlying physics of breakdown in the design of new polymeric dielectrics.
Size- and temperature-dependent Young’s modulus of individual ZnS nanobelts
Authors: Ma Liang , Jiang Yijun , Dai Guozhang , Mead James L , Yibibulla Tursunay , Lu Mingyuan , Huang Han , Fatikow Sergej , Wang Shiliang
Published: June 2022

The Young’s modulus of individual ZnS nanobelts with thicknesses ranging from 30 to 110 nm is measured by a mechanical resonance method over a temperature range of 300–650 K. Nanobelts with thicknesses above ∼80 nm exhibit a Young’s modulus very close to their corresponding bulk value of 88 GPa, whilst thinner nanobelts with thicknesses down to 30 nm exhibit a Young’s modulus of ∼70 GPa. Incrementally heating a nanobelt of 110 nm thickness over a temperature range of 300–650 K presents a linearly decreasing Young’s modulus. The nanobelt is thus found to possess a temperature coefficient of Young’s modulus of −125.4 ± 2.8 ppm K−1, which is comparable to their bulk value of −147 ppm K−1. The temperature coefficient of Young’s modulus for nanobelts with thicknesses below 100 nm demonstrates a strong size effect, and is found to dramatically decrease to as low as −201.4 ± 10.2 ppm K−1 for the thickness of 30 nm. A nonlinear temperature dependence of Young’s modulus is experimentally identified for nanobelt with diameters below 100 nm, and the linear-nonlinear transition temperature decreases with the decrease of nanobelt thickness.
EMD-based time–frequency denoising algorithm for the self-sensing of vibration signals in ultrasonic-assisted grinding
Authors: Zhang Jiahao , Sang Hande , Zhao Su
Published: June 2022

An empirical mode decomposition (EMD)-based time–frequency denoising algorithm is derived in this paper to accomplish the extraction of active ingredients for multi-frequency mixed signals, and then the self-sensing of vibration signals is realized without additional sensors for an ultrasonic-assisted grinding device. EMD is employed to accomplish the signal decomposition, and multiple intrinsic mode function components and the residual are obtained. Then, the weighted factors used for signal reconstruction are obtained based on innovation statistical distance, which is selected as a criterion to evaluate the time–frequency domain correlation between decomposition results and the original signal. Next, the maximum correntropy criterion-based similarity detection method is designed to adaptively modify the weighted factors, and the signal is reconstructed on the foundation of the modified weighted factors. Finally, numerical simulations and a self-sensing experiment are conducted to verify the denoising performance of the proposed algorithm. The self-sensing of the 4.59 dB vibration signal is realized for an ultrasonic-assisted grinding device.
Efficient quantum state preparation using Stern–Gerlach effect on cold atoms
Authors: Singh Vivek , Tiwari V B , Mishra S R
Published: June 2022

The Zeeman hyperfine state dependent force in a Stern–Gerlach experiment has been exploited to separate and quantitatively detect atoms in different Zeeman hyperfine states in a cold atom cloud of

87

Rb

atoms. Using this atomic state detection technique, the quantum state of the atom cloud has been prepared with high efficiency for magnetic trapping application.
Attomolar detection of 4-aminothiophenol by SERS using silver nanodendrites decorated with gold nanoparticles
Authors: Ceballos Manuel , López Israel , Arizmendi-Morquecho Ana , Sánchez-Domínguez Margarita
Published: June 2022

In the present work we report a simple, fast, reproducible and cheap methodology for surface enhanced Raman spectroscopy (SERS) substrate fabrication of silver dendritic nanostructures (prepared by electrodeposition) decorated with gold nanospheres by electrophoretic deposition. This is the first report where a metal dendritic nanostructure has been decorated with another type of metal nanoparticles by this technique. The decorated nanostructures were used directly as SERS substrate using 4-aminothiophenol (4-ATP) as analyte. The objective of the decoration is to create more hot-spots in order to detect the analyte in a lower concentration. Decorated nanodendrites had a detection limit one million times lower than bare silver nanodendrites and all the substrates showed an increase in the Raman intensity at concentrations below 1 nM; because this concentration corresponds to the threshold for the formation of a monolayer resulting in a triple mechanism of intensity increase, namely electric field, chemical factor and hot-spots. 4-ATP was detected in attomolar concentration, which is below 1 ppq, corresponding to an analytical enhancement factor in the order of 1015.
Active targeting of CD4+ T lymphocytes by PEI-capped, peptide-functionalized gold nanoparticles
Authors: Ncobeni Nomfundo , de la Torre Beatriz G , Albericio Fernando , Kruger Hendrik G , Parboosing Raveen
Published: June 2022

Active targeting is a promising approach for the treatment of viral infections. In particular, site-specific formulations for the treatment of HIV infection may overcome challenges associated with current ARV regimens. In this study we explored active targeting by synthesizing a gold nanoparticle construct decorated with an anti-CD4 cyclic peptide. The aim was to demonstrate selectivity of the system for the CD4 receptor and to deliver the RNA payload into T-lymphocytes. Colloidal gold nanoparticles functionalized with N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP) were formed by a one-pot synthesis method where thiol modified polyethyleneimine (PEI) was mixed with chloroauric acid. PEI-SPDP AuNPs (gold nanoparticles) were conjugated to an anti-CD4 peptide and loaded with RNA. We measured toxicity and uptake using TZM-bl and HeLa cells. Our findings show that the nanoparticles bind selectively to CD4 + cells. UV–vis characterisation of the nanoparticles revealed a surface plasmon resonance (SPR) peak at 527 nm, corresponding to a 6 nm diameter. HRTEM of the complete nanoparticles visualised circular shaped particles with average diameter of ∼7 nm. The polydispersity index was calculated to be 0.08, indicating monodispersity of complete NPS in solution. Through the pyridine-2-thione assay each nanoparticle was calculated to carry 1.37 × 105 SPDP molecules available for peptide binding. Flow cytometry showed that 13.6% of TZM-bl cells, and 0.14% of HeLa cells retained fluorescence after an overnight incubation, an indication of system binding. No internal RNA delivery was demonstrated. Further work is required to improve internalization.
Superconducting properties of Nb, NbN, and MoN thin films grown on topological insulator Bi1.95Sb0.05Se3: a comparative study
Authors: S Abhirami , Amaladass Edward Prabu , K Vinod , A V Thanikai Arasu , R Baskaran , Mani Awadhesh
Published: June 2022

The superconducting properties of DC magnetron sputtered Nb, NbN, and MoN films deposited on Sb-doped bismuth selenide (BSS) topological insulator films have been studied. In this two-fold study, firstly, thick superconducting films of ∼100 nm have been studied to find the modifications in the superconducting properties of the films caused by the surface morphology of pulsed laser deposition-grown BSS substrates. A drastic suppression in the critical current density has been observed in the bilayers, which has been ascribed to the strong influence of the substrate on the morphology of the superconducting film and the consequent enhancement in the density of superconducting weak links. The temperature dependence of the critical magnetic field has been carefully analyzed within the purview of the Werthamer–Hohenberg–Helfand theory, taking into account the effects of spin paramagnetism and spin–orbit scattering. In the second part of the study, ultra-thin bilayers of NbN-BSS, with thickness of the order of the coherence length (∼5 nm), have been grown to study the superconducting properties within the proximity regime. A ∼3.5 K suppression in T
c is seen in the NbN(5 nm)-BSS bilayer, due to a combination of interface roughness and superconducting proximity, while a suppression of 0.6 K has been observed in the BSS(6 nm)-NbN(5 nm) bilayer, which is surmised to be solely due to the superconducting proximity effect.
Closed-loop transcranial ultrasound stimulation with a fuzzy controller for modulation of motor response and neural activity of mice
Authors: Yuan Yi , Long Ai , Wu Yongkang , Li Xiaoli
Published: June 2022

Objective. We propose a closed-loop transcranial ultrasound stimulation (TUS) with a fuzzy controller to realize real-time and precise control of the motor response and neural activity of mice. Approach. The mean absolute value (MAV) of the electromyogram (EMG) and peak value (PV) of the local field potential (LFP) were measured under different ultrasound intensities. A model comprising the characteristics of the MAV of the EMG, PV of the LFP, and ultrasound intensity was built using a neural network, and a fuzzy controller, proportional-integral-derivative (PID) controller, and immune feedback controller were proposed to adjust the ultrasound intensity using the feedback of the EMG MAV and the LFP PV. Main results. In simulation, the quantitative calculation indicated that the maximum relative errors between the simulated EMG MAV and the expected values were 17% (fuzzy controller), 110% (PID control), 66% (immune feedback control); furthermore, the corresponding values of the LFP PV were 12% (fuzzy controller), 53% (PID control), 55% (immune feedback control). The average relative errors of fuzzy controller, PID control, immune feedback control were 4.97%, 13.15%, 11.52%, in the EMG closed-loop experiment and 7.76%, 11.84%, 13.56%, in the LFP closed-loop experiment. Significance. The simulation and experimental results demonstrate that the closed-loop TUS with a fuzzy controller can realize the tracking control of the motor response and neural activity of mice.
Causal impact of tearing mode on zonal flows and local turbulence in the edge of HL-2A plasmas
Authors: Xu J.Q. , Qu Y.R. , Li J.C. , Lin Z. , Dong J.Q. , Peng X.D. , Jiang M. , Qu H.P. , Huang Z.H. , Wu N. , Wang W.C. , Hao G.Z. , Chen W. , Li J.Q. , Xu M.
Published: June 2022

Direct causality analysis of the multi-scale interactions among macro-scale tearing mode (TM), meso-scale geodesic acoustic mode (GAM) and small-scale turbulence in the edge plasma of the HL-2A tokamak utilizing transfer entropy (TE) method is reported. Experimental results have demonstrated that the (m/n) = (2/1) (with m and n being the poloidal and toroidal mode numbers, respectively) TM modulates the turbulence with the frequency range of f = 50–150 kHz and the GAM mainly modulates that with higher frequencies. The TM has both amplitude and phase modulation on turbulence energy while the GAM has only amplitude regulation effect. TE analyses have shown that both TM and GAM will modulate the turbulence energy during which the impact of the former is of about an order magnitude larger than the latter, whereas the causal effect of TM on particle transport is about twice that of the GAM, which is due to the different causal effects on density and electric field fluctuations caused by TM and GAM, respectively. It is suggested that the magnetic fluctuation strongly modulates the Reynolds stress which serves as a mediator, leading to a cooperative interaction between TM and GAM in the edge of tokamak plasmas.
A benchtop induction-based AC magnetometer for a fast characterization of magnetic nanoparticles
Authors: Saari Mohd Mawardi , Sulaiman Mohd Herwan , Ahmad Hamzah , Lah Nurul Akmal Che , Sakai Kenji , Kiwa Toshihiko , Tsukada Keiji
Published: June 2022

In this study, we report a development of a benchtop induction-based AC magnetometer to realize a simple, wideband, and sensitive AC magnetometer for bio-sensing applications and characterization of magnetic nanoparticles (MNPs). We investigate the inductance and parasitic capacitance of six different pickup coil geometries and compare their sensitivity and usable frequency range. In the pickup coil design, the number of turns and coil section separation are varied from 200 to 400 turns, and 1 to 4 sections, respectively. We find that the usable frequency range is greatly affected by the pickup coil’s inductance due to the self-resonance phenomena compared to their parasitic capacitance. A low noise instrument amplifier circuit (AD8429, Analog Devices, USA) was integrated and fabricated on a printed circuit board to amplify the weak signal from the pickup coil. We also implement a generalized Goertzel algorithm to achieve fast signal amplitude and phase extractions at a frequency. The developed magnetometer shows a sensitivity of 10−8 Am2/√Hz at 6 Hz and a frequency range of up to 158 kHz. Using the developed AC magnetometer, we demonstrate the viscosity effect on the frequency response of thermally blocked, single-core nanoparticles (SHP30, Ocean Nanotech, USA) in glycerol solutions. The excitation frequency is swept from 5 Hz to 158 kHz at a field amplitude of 0.55 mTpp within the acquisition time of 5 min (51 points). As a result, the viscosity change is confirmed by the peak shifting in the imaginary magnetization curve towards lower frequency values when the wt/V% of the glycerol solution is increased. The hydrodynamic size and the average anisotropy energy ratio σ are estimated to be 60.6 nm and 25, respectively, from the complex AC magnetization. It can be expected that the developed AC magnetometer can be a valuable tool in providing a fast and reliable assessment of MNPs for bio-sensing applications.
A recursive Lovász theta number for simplex-avoiding sets
Authors: Castro-Silva Davi , de Oliveira Filho Fernando , Slot Lucas , Vallentin Frank
Published: June 2022

We recursively extend the Lovász theta number to geometric hypergraphs on the unit sphere and on Euclidean space, obtaining an upper bound for the independence ratio of these hypergraphs. As an application we reprove a result in Euclidean Ramsey theory in the measurable setting, namely that every

k
k

-simplex is exponentially Ramsey, and we improve existing bounds for the base of the exponential.
The classification of multiplicity-free plethysms of Schur functions
Authors: Bessenrodt Christine , Bowman Chris , Paget Rowena
Published: June 2022

We classify and construct all multiplicity-free plethystic products of Schur functions. We also compute many new (infinite) families of plethysm coefficients, with particular emphasis on those near maximal in the dominance ordering and those of small Durfee size.
Linked-Read Sequencing of Eight Falcons Reveals a Unique Genomic Architecture in Flux
Authors: Wilcox Justin J S , Arca-Ruibal Barbara , Samour Jaime , Mateuta Victor , Idaghdour Youssef , Boissinot Stéphane
Published: June 2022

Falcons are diverse birds of cultural and economic importance. They have undergone major lineage-specific chromosomal rearrangements, resulting in greatly reduced chromosome counts relative to other birds. Here, we use 10X Genomics linked reads to provide new high-contiguity genomes for two gyrfalcons, a saker falcon, a lanner falcon, three subspecies of peregrine falcons, and the common kestrel. Assisted by a transcriptome sequenced from 22 gyrfalcon tissues, we annotate these genomes for a variety of genomic features, estimate historical demography, and then investigate genomic equilibrium in the context of falcon-specific chromosomal rearrangements. We find that falcon genomes are not in AT–GC equilibrium with a bias in substitutions toward higher AT content; this bias is predominantly but not exclusively driven by hypermutability of CpG sites. Small indels and large structural variants were also biased toward insertions rather than deletions. Patterns of disequilibrium were linked to chromosomal rearrangements: falcons have lost GC content in regions that have fused to larger chromosomes from microchromosomes and gained GC content in regions of macrochromosomes that have translocated to microchromosomes. Inserted bases have accumulated on regions ancestrally belonging to microchromosomes, consistent with insertion-biased gene conversion. We also find an excess of interspersed repeats on regions of microchromosomes that have fused to macrochromosomes. Our results reveal that falcon genomes are in a state of flux. They further suggest that many of the key differences between microchromosomes and macrochromosomes are driven by differences in chromosome size, and indicate a clear role for recombination and biased gene conversion in determining genomic equilibrium.
Pacific Healthy Islands Vision: success factors and challenges faced by health promotion programs
Authors: Martin Erik , Snowdon Wendy , Moadsiri Ada , Volavola Saula , Bell Colin
Published: June 2022

The World Health Organization’s (WHO) Western Pacific Regional Office developed the biennial Healthy Islands Recognition Awards (HIA) in 2009 to reinforce the Healthy Islands vision and encourage countries to continue to innovate and demonstrate effective and efficient ways of promoting and protecting population health. This research aimed to identify characteristics of and challenges for successful health promotion in the Pacific. The research was undertaken to develop practical guidance for other groups in the Pacific Islands interested in supporting Healthy Islands. We used a qualitative case study to review 2013 and 2015 HIA awardees from eight Pacific Island countries and territories using a set of questions drawn from the HIA application criteria. In 2015–2016, 35 key informant interviews and a review of program documents were undertaken. This was followed by a workshop with representatives from three HIA awardees to further develop recommendations. We reviewed eight programs targeting healthy eating, physical activity, healthy settings and sanitation. Using evidence, careful planning, building capacity, developing partnerships, strengthening and reorientating networks, ensuring accountability and conducting evaluation were keys to the success of healthy islands projects. Considering the local setting and community was perhaps the most crucial theme amongst the programs examined. Challenges included funding and capacity constraints, maintaining commitment and prioritisation, maintaining communication and coordination and technical challenges. Success factors, challenges and recommendations aligned well with mainstream health promotion literature, although some important distinctions exist. Further research is needed to guide successful health promotion practice in the Pacific.
How quickly does a wound heal? Bayesian calibration of a mathematical model of venous leg ulcer healing
Authors: Zanca Adriana , Osborne James M , Zaloumis Sophie G , Weller Carolina D , Flegg Jennifer A
Published: June 2022

Chronic wounds, such as venous leg ulcers, are difficult to treat and can reduce the quality of life for patients. Clinical trials have been conducted to identify the most effective venous leg ulcer treatments and the clinical factors that may indicate whether a wound will successfully heal. More recently, mathematical modelling has been used to gain insight into biological factors that may affect treatment success but are difficult to measure clinically, such as the rate of oxygen flow into wounded tissue. In this work, we calibrate an existing mathematical model using a Bayesian approach with clinical data for individual patients to explore which clinical factors may impact the rate of wound healing for individuals. Although the model describes group-level behaviour well, it is not able to capture individual-level responses in all cases. From the individual-level analysis, we propose distributions for coefficients of clinical factors in a linear regression model, but ultimately find that it is difficult to draw conclusions about which factors lead to faster wound healing based on the existing model and data. This work highlights the challenges of using Bayesian methods to calibrate partial differential equation models to individual patient clinical data. However, the methods used in this work may be modified and extended to calibrate spatiotemporal mathematical models to multiple data sets, such as clinical trials with several patients, to extract additional information from the model and answer outstanding biological questions.
#22 Does Cranial Ultrasound Differentiate Asymptomatic Congenital CMV (cCMV) Infection from cCMV with Central Nervous System Disease in Infants? Results from a Universal Screening Study in Minnesota, USA
Authors: Kruc Rebecca
Published: June 2022

Background

Congenital cytomegalovirus (cCMV) is the most common infectious cause of neurodevelopmental deficits, including sensorineural hearing loss (SNHL). With the passage of a universal cCMV screening bill by the Minnesota legislature in 2021, it is imperative to define the optimal diagnostic approach for identified cases, particularly for asymptomatic infants. Cerebral ultrasound (US) is a safe, non-invasive technique to examine neonatal brains, and has been advocated by an international consensus panel as a modality for cCMV disease classification. This analysis described clinical manifestations of cCMV in infants identified by universal screening and characterized cranial US findings obtained during diagnostic evaluation. We correlated viral load in the newborn CMV screening saliva samples with clinical and US findings.

Method

Newborns were screened for cCMV at six Twin Cities nurseries by PCR of dried blood spots (DBS) obtained for routine newborn screening, and saliva collected 1-2 days after birth. Screen-positive infants had a confirmatory urine PCR test within 3 weeks of birth, and clinical evaluation that included cranial US.

Results

Through September 1, 2021, 19,017 newborns were screened for cCMV. 76 cases were identified (prevalence of 0.4%) by saliva or DBS, confirmed by urine CMV PCR testing. 76% (58/76) had asymptomatic cCMV; the remaining 24% were infants with cCMV disease. Nine had congenital or delayed-onset SNHL, of which 7 had abnormal US; 1 had normal US, and 1 did not have US performed. Median saliva viral load differed between infants with cCMV disease (3.3×104 IU/ml) and asymptomatic infants (8.6×106 IU/ml; p< 0.05, Fig. 1). Cranial US exams were available for 68 infants (51 asymptomatic, 17 with cCMV disease). 50 (74%) infants had normal US; 18 infants had abnormal US (Table 1). Of the 17 infants with cCMV disease, 12 had abnormal US, of which 4 showed cCMV disease-defining lesions. Of 51 asymptomatic infants, 6 had abnormal, and 45 normal, cranial US. Saliva viral loads did not vary between infants with normal vs. abnormal US (p=0.7).

Conclusion

PCR of newborn DBS and/or saliva revealed a prevalence of 4.0 per 1000 in a universal cCMV screening study. Surprisingly, an inverse relationship was observed between saliva viral load at birth and cCMV disease classification. Among babies with cCMV, the majority had normal cranial US, and most abnormalities were not pathognomonic for cCMV disease. Clarification is needed regarding which cranial US findings require detailed follow-up, including MRI, as universal cCMV screening programs move forward in clinical practice.
#73 Single Cell RNA Sequencing of Zika Infection in Neural Tissues Reveals an Astrocyte-Driven Innate Immune Response Governed by Interferon Beta.
Authors: Stokes Caleb
Published: June 2022

Background

Congenital infection with Zika virus (ZIKV) has been linked to severe of fetal brain disruption and other developmental anomalies referred to collectively as congenital Zika syndrome (CZS). Long-term follow up of ZIKV-exposed infants has shown that even those without overt findings of CZS can have significant cognitive and developmental difficulties. However, the pathogenesis of ZIKV-related microcephaly and cognitive dysfunction remain poorly understood. To begin answering these questions, we sought to define the consequences of ZIKV infection on specific cell types in the developing brain.

Method

We have used primary human fetal brain cultures and human induced pluripotent stem cell-derived neural progenitor cell lines to probe innate immune signaling to ZIVK infection in vitro. We used single-cell RNA sequencing (10x Genomics) to identify the cell type-specific transcriptional changes induced by ZIKV infection.

Results

We found that neural progenitor cells (NPCs) support higher ZIKV RNA copy number than do differentiated neural cells. Moreover, while IFN-β is the predominant cytokine released by differentiated cells in response to ZIKV infection, NPCs do not produce IFN-β. By additionally characterizing the transcriptional response to IFN-β treatment, we have been able to distinguish virus-stimulated genes (VSGs) from interferon-stimulated genes (ISGs) across cell types. We find extensive heterogeneity in cell type-specific VSG and ISG profiles. Astrocytes undergo the largest transcriptional changes in response to infection and are the main producers of IFN-β. Our findings also identify genes whose expression is altered during viral infection specifically in NPCs and neurons, providing candidate pathways that may underlie neural dysfunction.

Conclusion

Across cell types, the response to Zika infection closely matches the response to IFN-β, arguing that astrocyte-derived IFN-β is the main driver of the innate immune response to ZIKV in the developing brain. Our findings provide insight into the pathogenesis of CZS and offer novel targets for improving developmental outcomes after fetal ZIKV infection.
#59 Efficacy of Oral Cryotherapy in the Prevention of Oral Mucositis during high dose chemotherapy infusion for children with autologous stem cell transplant
Authors: Hoa Nguyen Thi Kim
Published: June 2022

Background

Oral mucositis is one of the most common and distressing side effects of cancer therapy, especially high dose chemotherapy. This study aims to evaluate the effectiveness of oral cryotherapy in prevention oral mucositis in children with autologous stem cell transplant

Method

A prospective study was carried out in children receiving autologous stem cell transplant since December, 2019 to December, 2021 at Hue Central hospital in Vietnam. All patient were received oral cryotherapy during chemotherapeutic agents infusion. The way to measure oral mucositis with specific scale based on WHO grading system for oral mucositis. Data was abstracted from patient medical records and analyzed in SPSS v.18.0 (IBM Corp., Armonk, NY, USA).

Results

From December, 2019 to December, 2021, a total of 20 patients receiving autologous stem cell transplantation, with a median age of 3.75 years (range: 2.5 years to 8 years). Of these patients, 18 patients (90%) was diagnosed high risk neuroblastoma and treated with regimen conditioning: Busulfan and melphalan; 1 patient (5%) was diagnosed relapsed Burkitt lymphoma and used high dose chemotherapy with carmustine, etoposide, cytarabine and melphalan; 1 patient was diagnosed metastatic retinoblastoma and treated with carboplatin, etoposide and thiotepa. During oral cryotherapy, all the patients tolerated well and had no side effect. 15% patients did not have any signs of oral mucositis, 85% of patients had oral mucositis, in which grade I mucositis accounted for 70% and grade II mucositis accounted for 15%. The median time for oral mucositis recovery was 5 days (range: 4 days to 11 days).

Conclusion

Oral cryotherapy is effective in preventing oral mucositis in patients undergoing high dose chemotherapy for the autologous stem cell transplantation. However, we need to implement and evaluate in the larger number of patients.
#60 TWO MONTH FOLLOW-UP OF PATIENTS WITH ACUTE COVID-19 AND MULTISYSTEM INFLAMMATORY SYNDROME IN CHILDREN
Authors: Racko I
Published: June 2022

Background

Children infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are usually asymptomatic or have mild coronavirus disease (COVID) with low rates of hospitalization. Two long-term consequences have been described after SARS-CoV-2 infection. The first is multisystem inflammatory syndrome in children (MIS-C) and the second is “long COVID”. Data on long COVID in pediatric patients has increasingly been published, giving new insights into the ways this phenomenon affects children. This study aimed to describe the persistent symptom spectrum of patients with acute SARS-CoV-2 infection and MIS-C two months after the diagnosis.

Method

This was a prospective cohort study conducted at the Children's Clinical University Hospital in Latvia. The study population of pediatric COVID-19 and MIS-C patients were invited to participate between December 1, 2020, and December 31, 2021. The study included children with moderate and severe acute SARS-CoV-2 infection who required hospitalization and MIS-C. Overall, 53 acute Covid-19 and 22 MIS-C patients were enrolled in the study. All patients were evaluated by specially designed assessment protocols. The Ethics Committee of Riga Stradins University reviewed and approved the study protocol questionnaire and informed consent forms (approval No. 6-1/07/35). Descriptive statistics were used to present the data.

Results

Data showed that two months after acute SARS-CoV-2 infection 84% (n=45) of patients had at least one persistent symptom. In addition, 73% (n=16) of MIS-C patients reported at least one persistent symptom. Generally, the most commonly reported complaints among COVID-19 patients included rhinorrhea (41%), cognitive sequelae such as mood swings (38%) and irritability (36%), prolonged cough (30%), anxiety (19%), night sweats (15%), sore throat and shortness of breath (13%). In the MIS-C patient group - body weight changes and mood swings (36%), irritability (27%), poor attention (23%), fatigue (18%), and in 14% of cases were observed myalgia, night sweats, difficulties concentrating and anxiety. There were other similar but less common complaints in both groups, such as prolonged fever, nausea, shortness of breath, dizziness and memory impairment.

Conclusion

We found that at the time of interview more than half of COVID-19 and MIS-C patients reported at least one persistent symptom. Symptoms including rhinorrhea, mood swings, irritability, prolonged cough, poor attention and fatigue were the most frequently reported complaints of long COVID-19 after acute SARS-CoV-2 infection and MIS-C, representing the wide range of symptoms affecting children.
Comparison of PneumID real-time PCR assay with Amplex eazyplex LAMP assay for laboratory diagnosis of Pneumocystis jirovecii Pneumonia
Authors: Ng Willy W Y , Ho Yolanda I I , Wong Ann H , Leung Eddie C M , Lee Alfred L H , Chow Viola C Y
Published: June 2022

We compared PneumID PCR with Amplex eazyplex LAMP assay for the diagnosis of Pneumocystis jirovecii pneumonia (PJP). Both assays enable the accurate diagnosis of definite PJP. Cut-off cycle threshold of the PneumID assay was <26.68 while the cut-off time-to-positivity of the eazyplex assay was 16:02 (minutes:seconds). The positive and negative percentage agreement of eazyplex assay with PneumID assay was 75% and 100% respectively, while the overall agreement was substantial with kappa = 0.80. For both assays, the establishment of cut-off values to differentiate probable PJP from colonization was not feasible as results overlapped.

Lay Summary

Both PneumID PCR and Amplex eazyplex LAMP assay enable accurate diagnosis of definite Pneumocystis jirovecii pneumonia (PJP). PneumID assay was more sensitive than eazyplex assay for detection of P. jirovecii. However, differentiation between probable PJP from colonization was not feasible.