bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel design of high performance and robust ultra-low power SRAM cell based on memcapacitor
Authors: Abbasi Alireza , Setoudeh Farbod , Tavakoli Mohammad Bagher , Horri Ashkan
Published: December 2021

The present paper proposes a six-FinFET two-memcapacitor (6T2MC) non-volatile static random-access memory (NVSRAM). In this design, the two memcapacitors are used as non-volatile memory elements. The proposed cell is flexible against data loss when turned off and offers significant improvement in read and write operations compared to previous NVSRAMs. The performance of the new NVSRAM design is evaluated in terms of read and write operation at particular nanometric feature sizes. Moreover, the proposed 6T2MC cell is compared with 8T2R, 8T1R, 7T1R, and 7T2R cells. The results show that 6T2MC has a 5.50% lower write delay and 98.35% lower read delay compared to 7T2R and 7T1R cells, respectively. The 6T2MC cell exhibits 38.86% lower power consumption and 23.80% lower leakage power than 7T2R and 7T1R cells. The proposed cell is significantly improved in terms of HSNM, RSNM, and WSNM compared to 8T2R, 8T1R, 7T2R, and 7T1R cells, respectively. Important cell parameters, such as power consumption, data read/write delay, and SNM, are significantly improved. The superior characteristics of FinFET over MOSFET and the combination of this technology with memcapacitors lead to significant improvement in the proposed design.
High-yield synthesis of CsPbBr3 nanoparticles: diphenylphosphine as a reducing agent and its effect in Pb-seeding nucleation and growth
Authors: Castillo-Ruiz Eder A , Garcia-Gutierrez Diana F , Garcia-Gutierrez Domingo I
Published: December 2021

Based on the reported nucleation mechanisms for CsPbX3 and II–VI/IV–VI quantum dots, CsPbBr3 nanoparticles with a higher reaction-yield (up to 393% mass-increment) were synthetized by the hot-injection method. The introduction of diphenylphosphine (DPP) as a reducing agent improved nanoparticle nucleation and growth, giving out evidence for Pb-seeding in CsPbBr3 nanoparticles formation. Additionally, a clear influence of the DPP in a CsPbBr3-Cs4PbBr6 incomplete phase transformation was observed, marked by the appearance of several PbBr2 nanoparticles. This indicated the need for an improved ratio between the stabilizing agents and the precursors, due to the increased number of nucleation sites produced by DPP. The resulting CsPbBr3 nanoparticles showed high quality, as they displayed 70%–90% photoluminescence quantum yield; narrow size distribution with an average nanoparticle size of ∼10 nm; and the characteristic cubic morphology reported in previous works. This increment in CsPbBr3 nanoparticles’ reaction yield will contribute to making them a more attractive option for different optoelectronic applications.
Interference and diffraction experiment using 3D printing and Arduino
Authors: Paixão P A , Remonatto V M C , Calheiro L B , Dos Reis D D , Goncalves A M B
Published: December 2021

Here, we present a 3D printed experimental apparatus that students can use to acquire interference and diffraction quantitative data from light passing through a single or double-slit experiment. We built a linear screw stage with a multiturn potentiometer connected to its leadscrew as a position sensor. Using an Arduino, we collected light intensity data (from a photodiode mounted in the linear stage) as a function of position. The apparatus is a low-cost and compact alternative with data acquisition to optics physics laboratories.
Development of laboratory devices for real-time measurement of object 3D position using stereo cameras
Authors: Ristanto Sigit , Nugroho Waskito , Sulistya Eko , Suparta Gede B
Published: December 2021

Measuring the 3D position at any time of a given object in real-time automatically and well documented to understand a physical phenomenon is essential. Exploring a stereo camera in developing 3D images is very intriguing since a 3D image perception generated by a stereo image may be reprojected back to generate a 3D object position at a specific time. This research aimed to develop a device and measure the 3D object position in real-time using a stereo camera. The device was constructed from a stereo camera, tripod, and a mini-PC. Calibration was carried out for position measurement in X, Y, and Z directions based on the disparity in the two images. Then, a simple 3D position measurement was carried out based on the calibration results. Also, whether the measurement was in real-time was justified. By applying template matching and triangulation algorithms on those two images, the object position in the 3D coordinate was calculated and recorded automatically. The disparity resolution characteristic of the stereo camera was obtained varied from 132 pixels to 58 pixels for an object distance to the camera from 30 cm to 70 cm. This setup could measure the 3D object position in real-time with an average delay time of less than 50 ms, using a notebook and a mini-PC. The 3D position measurement can be performed in real-time along with automatic documentation. Upon the stereo camera specifications used in this experiment, the maximum accuracy of the measurement in X, Y, and Z directions are ΔX = 0.6 cm, ΔY = 0.2 cm, and ΔZ = 0.8 cm at the measurement range of 30 cm–60 cm. This research is expected to provide new insights in the development of laboratory tools for learning physics, especially mechanics in schools and colleges.
Challenge on conservation of angular momentum
Authors: Espinosa J A , Ribas F , Lusquiños F
Published: December 2021

In order to fix some important concepts of Fundamental Physics, either because they are not usually discussed in depth in theoretical classes and much less at laboratories, or because they are not sufficiently developed in textbooks, it is more effective not to tackle them directly, but to propose a mental or practical experiment to attract the student’s attention by questioning their beliefs about it (erroneous preconceptions). We propose a new example about the conservation of angular momentum of a system of material points in this way previously explained.
How to make a multi-billion dollar thermometer
Authors: Baird William H
Published: December 2021

The United States’ Global Positioning System (GPS), and similar geolocation systems such as Galileo, GLONASS, and Beidou are used by people all over the globe. Modern receivers of these global navigation satellite systems can track multiple satellites from different constellations. Casual, non-technical users are probably aware that the positional information provided is typically accurate to within a few meters. We could expect physics students to infer that, because these systems rely on the travel time of radio signals, this implies time measurement accuracy on the scale of tens of nanoseconds. This feature has led to GPS-enabled Internet time servers providing stratum 1 accuracy for under $1000. In this paper, we will show that we can couple a GPS unit to a field programmable gate array (FPGA) to determine the temperature in a room. The more serious application of this GPS-FPGA pairing is to provide precise time-stamping of events, thereby synchronizing data collection between stations across a room or across the globe.
Theoretical aspects on the use of single-time-point dosimetry for radionuclide therapy
Authors: Gustafsson Johan , Taprogge Jan
Published: December 2021

Objective. This study considers the error distributions for time-integrated activity (TIA) of single-time-point (STP) methods for patient-specific dosimetry in radionuclide therapy. Approach. The general case with the same pharmaceutical labelled with different radionuclides for imaging and therapy are considered for a mono-exponential time-activity curve. Two methods for STP dosimetry, both based on the combination of one activity estimate with the population-mean effective decay constant, are investigated. The cumulative distribution functions (CDFs) and the probability density functions for the two methods are analytically derived for arbitrary distributions of the biological decay constant. The CDFs are used for determining 95% coverage intervals of the relative errors for different combinations of imaging time points, physical decay constants, and relative standard deviations of the biological decay constant. Two examples, in the form of kidney dosimetry in [177Lu]Lu-DOTA-TATE therapy and tumour dosimetry for Na[131I]I therapy for thyroid cancer with dosimetry based on imaging of Na[124I]I, are also studied in more detail with analysis of the sensitivity with respect to errors in the mean biological decay constant and to higher moments of the distribution. Main results. The distributions of the relative errors are negatively skewed, potentially leading to the situation that some TIA estimates are highly underestimated even if the majority of estimates are close to the true value. Significance. The main limitation of the studied STP dosimetry methods is the risk of large underestimations of the TIA.
Magnetic state switching in FeGa microstructures
Authors: Guevara De Jesus Michael , Xiao Zhuyun , Goiriena-Goikoetxea Maite , Chopdekar Rajesh V , Panduranga Mohanchandra K , Shirazi Paymon , Acosta Adrian , Chang Jane P , Bokor Jeffrey , Carman Gregory P , Candler Rob N , Lynch Christopher
Published: December 2021

This work demonstrates that magnetoelectric composite heterostructures can be designed at the length scale of 10µms that can be switched from a magnetized state to a vortex state, effectively switching the magnetization off, using electric field induced strain. This was accomplished using thin film magnetoelectric heterostructures of Fe81.4Ga18.6on a single crystal (011) [Pb(Mg1/3Nb2/3)O3]0.68-[PbTiO3]0.32(PMN-32PT) ferroelectric substrate. The heterostructures were tripped from a multi-domain magnetized state to a flux closure vortex state using voltage induced strain in a piezoelectric substrate. FeGa heterostructures were deposited on a Si-substrate for superconducting quantum interference device magnetometry characterization of the magnetic properties. The magnetoelectric coupling of a FeGa continuous film on PMN-32PT was characterized using a magneto optical Kerr effect magnetometer with bi-axial strain gauges, and magnetic multi-domain heterostructures were imaged using x-ray magnetic circular dichroism—photoemission electron microscopy during the transition to the vortex state. The domain structures were modelled using MuMax3, a micromagnetics code, and compared with observations. The results provide considerable insight into designing magnetoelectric heterostructures that can be switched from an ‘on’ state to an ‘off’ state using electric field induced strain.
Bath-induced decoherence in finite-size Majorana wires at non-zero temperature
Authors: Breckwoldt Niels , Posske Thore , Thorwart Michael
Published: December 2021

Braiding Majorana zero-modes around each other is a promising route toward topological quantum computing. Yet, two competing maxims emerge when implementing Majorana braiding in real systems: on the one hand, perfect braiding should be conducted adiabatically slowly to avoid non-topological errors. On the other hand, braiding must be conducted fast such that decoherence effects introduced by the environment are negligible, which are generally unavoidable in finite-size systems. This competition results in an intermediate time scale for Majorana braiding that is optimal, but generally not error-free. Here, we calculate this intermediate time scale for a T-junction of short one-dimensional topological superconductors coupled to a bosonic bath that generates fluctuations in the local electric potential, which stem from, e.g. environmental photons or phonons of the substrate. We thereby obtain boundaries for the speed of Majorana braiding with a predetermined gate fidelity. Our results emphasize the general susceptibility of Majorana-based information storage in finite-size systems and can serve as a guide for determining the optimal braiding times in future experiments.
Ab-initio study of mechanical and thermoelectric properties of topological semimetal: LaAuPb
Authors: Goyal Megha , Sinha M. M.
Published: December 2021

Heusler compounds are a tuneable class of material with a cubic crystal structure that can serve as a platform to study the topological phase of a material. These materials have numerous technological and scientific applications. So, in the present work, the mechanical, thermodynamical, and thermoelectric properties of LaAuPb in the topological phase have been reported by using density functional theory and Boltzmann transport theory. LaAuPb is mechanically stable, and the Poisson ratio reveals its ductile nature. The specific heat of the proposed compound at room temperature is 73.94 J K−1 mol−1 at constant volume. Debye’s temperature is estimated to be 188.64 K. Moreover, the lattice thermal conductivity of the compound is 14.64 W mK−1 and 3.66 W mK−1 at 300 K and 1200 K, respectively. The good thermoelectric response of LaAuPb can be confirmed by its high value of the figure of merit (0.46) at 1200 K. Hence, it is a potential material for thermoelectric applications. This work will help future researchers to better understand the stability, nature, and behavior of LaAuPb in material fabrication.
Quantitative simulations of ratchet potential in a dusty plasma ratchet
Authors: Wang Shuo , Zhang Ning , Zhang Shun-Xin , Tian Miao , Cai Ya-Wen , Fan Wei-Li , Liu Fu-Cheng , He Ya-Feng
Published: December 2021

Using a dusty plasma ratchet, one can realize the rectification of charged dust particle in a plasma. To obtain the ratchet potential dominating the rectification, here we perform quantitative simulations based on a two-dimensional fluid model of capacitively coupled plasma. Plasma parameters are firstly calculated in two typical cross sections of the dusty plasma ratchet which cut vertically the saw channel at different azimuthal positions. The balance positions of charged dust particle in the two cross sections then can be found exactly. The electric potentials at the two balance positions have different values. Using interpolation in term of a double-sine function from previous experimental measurement, an asymmetrical ratchet potential along the saw channel is finally obtained. The asymmetrical orientation of the ratchet potential depends on discharge conditions. Quantitative simulations further reproduce our previous experimental phenomena such as the rectification of dust particle in the dusty plasma ratchet.
Single-polarization single-mode hollow-core negative curvature fiber with nested U-type cladding elements
Authors: Wang Qi-Wei , Qiu Shi , Yuan Jin-Hui , Zhou Gui-Yao , Xia Chang-Ming , Qu Yu-Wei , Zhou Xian , Yan Bin-Bin , Wu Qiang , Wang Kui-Ru , Sang Xin-Zhu , Yu Chong-Xiu
Published: December 2021

Hollow-core negative curvature fibers (HC-NCFs) have become one of the research hotspots in the field of optical fiber because of their potential applications in the data and energy transmissions. In this work, a new kind of single-polarization single-mode HC-NCF with nested U-type cladding elements is proposed. To achieve the single-polarization single-mode transmission, we use two different silica tubes in thickness, which satisfy the resonance and anti-resonance conditions on the U-type cladding elements and the cladding tubes, respectively. Besides, the elliptical elements are introduced to achieve good single-mode performance. By studying the influences of the structure parameters on the propagation characteristics, the optimized structure parameters are obtained. The simulation results show that when the wavelength is fixed at 1550 nm, the single-polarization single-mode transmission is achieved, with the polarization extinction ratio of 25749 and minimum high-order mode extinction ratio of 174. Furthermore, the confinement loss is only 0.0015 dB/m.
Probing dark contents in globular clusters with timing effects of pulsar acceleration
Authors: Wang Li-Chun , Xie Yi
Published: December 2021

We investigate pulsar timing residuals due to the coupling effect of the pulsar transverse acceleration and the Römer delay. The effect is relatively small and usually negligible. Only for pulsars in globular clusters, it is possibly important. The maximum residual amplitude, which is from the pulsar near the surface of the core of the cluster, is about tens of nanoseconds, and may hardly be identified for most globular clusters currently. However, an intermediate-mass black hole in the center of a cluster can apparently increase the timing residual magnitudes. Particularly for pulsars in the innermost core region, their residual magnitudes may be significant. The high-magnitude residuals, which are above critical lines of each cluster, are strong evidence for the presence of a black hole or dark remnants of comparable total mass in the center of the cluster. We also explored the timing effects of line-of-sight accelerations for the pulsars. The distribution of measured line-of-sight accelerations are simulated with a Monte Carlo method. Two-dimensional Kolmogorov-Smirnov tests are performed to reexamine the consistency of distributions of the simulated and reported data for various values of parameters of the clusters. It is shown that the structure parameters of Terzan 5 can be constrained well by comparing the distribution of measured line-of-sight accelerations with the distributions from Monte Carlo simulations. We find that the cluster has an upper limit on the central black hole/dark remnant mass of ∼ 6000 M
⊙.
Influence of aspect ratio, plasma viscosity, and radial position of the resonant surfaces on the plasmoid formation in the low resistivity plasma in Tokamak
Authors: Zhang W. , Ma Z.W. , Zhang H.W. , Chen W.J. , Wang X.
Published: December 2021

In the present paper, we systematically investigate the nonlinear evolution of the resistive kink mode in the low resistivity plasma in Tokamak geometry. We find that the aspect ratio of the initial equilibrium can significantly influence the critical resistivity for plasmoid formation. With the aspect ratio of 3/1, the critical resistivity can be one magnitude larger than that in cylindrical geometry due to the strong mode–mode coupling. We also find that the critical resistivity for plasmoid formation η
crit decreases with increasing plasma viscosity in the moderately low resistivity regime. Due to the geometry of Tokamaks, the critical resistivity for plasmoid formation increases with the increasing radial location of the resonant surface.
Global land use extent and dispersion within natural land cover using Landsat data
Authors: Hansen Matthew C , Potapov Peter V , Pickens Amy H , Tyukavina Alexandra , Hernandez-Serna Andres , Zalles Viviana , Turubanova Svetlana , Kommareddy Indrani , Stehman Steve V , Song Xiao-Peng , Kommareddy Anil
Published: December 2021

The conversion of natural land cover into human-dominated land use systems has significant impacts on the environment. Global mapping and monitoring of human-dominated land use extent via satellites provides an empirical basis for assessing land use pressures. Here, we present a novel 2019 global land cover, land use, and ecozone map derived from Landsat satellite imagery and topographical data using derived image feature spaces and algorithms suited per theme. From the map, we estimate the spatial extent and dispersion of land use disaggregated by climate domain and ecozone, where dispersion is the mean distance of land use to all land within a subregion. We find that percent of area under land use and distance to land use follow a power law that depicts an increasingly random spatial distribution of land use as it extends across lands of comparable development potential. For highly developed climate/ecozones, such as temperate and sub-tropical terra firma vegetation on low slopes, area under land use is contiguous and remnant natural land cover have low areal extent and high fragmentation. The tropics generally have the greatest potential for land use expansion, particularly in South America. An exception is Asian humid tropical terra firma vegetated lowland, which has land use intensities comparable to that of temperate breadbaskets such as the United States’ corn belt. Wetland extent is inversely proportional to land use extent within climate domains, indicating historical wetland loss for temperate, sub-tropical, and dry tropical biomes. Results highlight the need for planning efforts to preserve natural systems and associated ecosystem services. The demonstrated methods will be implemented operationally in quantifying global land change, enabling a monitoring framework for systematic assessments of the appropriation and restoration of natural land cover.
Effect of interaction from the reaction of carboxyl/epoxy hyperbranched polyesters on properties of feedstocks for metal injection molding
Authors: Chen Guoming , Ma Haihong , Zhou Zhengfa , Ren Fengmei , Xu Weibing
Published: December 2021

The purpose of this study is to improve the properties of the feedstocks and shape retention of debinded parts by the reaction between 17-4PH stainless steel powders. Carboxyl-terminated hyperbranched polyester (CTHP) and epoxy-terminated hyperbranched polyester (ETHP) were used to treat the powders, and termed as CTHP-m and ETHP-m with carboxyl and epoxy group, respectively. Comparing with pristine, CTHP-m and ETHP-m, feedstock prepared from equal amount of CTHP-m and ETHP-m (CTHP-m/ETHP-m) possessed more excellent properties. The experimental results showed that the critical solids loading, flexural modulus, density and melt flow index of CTHP-m/ETHP-m feedstock were 63.8 vol.%, 2800 Mpa, 5.06 g cm−3 and 62 g/10 min, respectively, which were obviously higher than that of others. Also, the shape retention of CTHP-m/ETHP-m debinded parts was the best of all the samples. The improved properties of CTHP-m/ETHP-m feedstock were attributed to the powder interaction between CTHP-m and ETHP-m formed by the chemical reaction between epoxy and carboxyl group.
Unmanned aerial vehicles and deep learning for assessment of anthropogenic marine debris on beaches on an island in a semi-enclosed sea in Japan
Authors: Takaya Kosuke , Shibata Atsuki , Mizuno Yuji , Ise Takeshi
Published: December 2021

The increasing prevalence of marine debris is a global problem, and urgent action for amelioration is needed. Identifying hotspots where marine debris accumulates will enable effective control; however, knowledge on the location of accumulation hotspots remains incomplete. In particular, marine debris accumulation on beaches is a concern. Surveys of beaches require intensive human effort, and survey methods are not standardized. If marine debris monitoring is conducted using a standardized method, data from different regions can be compared. With an unmanned aerial vehicle (UAV) and deep learning computational methods, monitoring a wide area at a low cost in a standardized way may be possible. In this study, we aimed to identify marine debris on beaches through deep learning using high-resolution UAV images by conducting a survey on Narugashima Island in the Seto Inland Sea of Japan. The flight altitude relative to the ground was set to 5 m, and images of a 0.81-ha area were obtained. Flight was conducted twice: before and after the beach cleaning. The combination of UAVs equipped with a zoom lens and operation at a low altitude allows for the acquisition of high resolution images of 1.1 mm/pixel. The training dataset (2970 images) was annotated by using VoTT, categorizing them into two classes: ‘anthropogenic marine debris’ and ‘natural objects.’ Using RetinaNet, marine debris was identified with an average sensitivity of 51% and a precision of 76%. In addition, the abundance and area of marine debris coverage were estimated. In this study, it was revealed that the combination of UAVs and deep learning enables the effective identification of marine debris. The effects of cleanup activities by citizens were able to be quantified. This method can widely be used to evaluate the effectiveness of citizen efforts toward beach cleaning and low-cost long-term monitoring.
Adherence to Recommended Preventive Behaviors During the COVID-19 Pandemic: The Role of Empathy and Perceived Health Threat
Authors: Morstead Talia , Zheng Jason , Sin Nancy L , King David B , DeLongis Anita
Published: December 2021

Background

Coping via empathic responding may play a role in preventive behavior engagement during the COVID-19 pandemic, and unlike trait empathy, is a potentially alterable target for changing health behavior.

Purpose

Our goal was to examine the role of empathic responding in preventive behavior engagement during the COVID-19 pandemic, independent of trait empathy and perceived threat of COVID-19.

Methods

Participants (N = 2,841) completed a baseline survey early in the pandemic, and a follow-up survey approximately 2 weeks later (M = 13.50 days, SD = 5.61). Preventive health behaviors, including physical distancing and hygiene practices, were assessed at both timepoints. Hierarchical linear regression examined the contributions of trait empathy, perceived threat of COVID-19, and empathic responding at baseline to preventive behaviors at follow-up.

Results

Controlling for baseline levels of preventive behaviors and demographic covariates, trait empathy and threat of COVID-19 at baseline were each independently associated with preventive behaviors at follow-up. An interaction between perceived threat and empathic responding indicated that those perceiving high threat of COVID-19 at baseline tended to report engaging in preventive behaviors at follow-up regardless of their levels of empathic responding, whereas for those reporting low levels of perceived threat, higher levels of empathic responding were associated with higher engagement in preventive behavior.

Conclusions

When perceived threat of COVID-19 was low, higher empathic responding was associated with increased engagement in preventive behaviors regardless of trait empathy, suggesting that empathic responding can serve as an actionable target for intervention to promote preventive behavior during the pandemic.
Behavioral and Cognitive Outcomes of an Online Weight Loss Program for Men With Low Mood: A Randomized Controlled Trial
Authors: Drew Ryan J , Morgan Philip J , Collins Clare E , Callister Robin , Kay-Lambkin Frances , Kelly Brian J , Young Myles D
Published: December 2021

Background

Depression and obesity are major health concerns and commonly co-exist, but men rarely seek help for these conditions. SHED-IT: Recharge was a gender-tailored eHealth program for men that generated clinically meaningful improvements in weight and depressive symptoms.

Purpose

To evaluate behavioral and psychological outcomes from the SHED-IT: Recharge intervention designed for overweight/obese men with low mood.

Methods

Overall, 125 men (18–70 years) with a BMI between 25 and 42 kg/m2 and depressive symptoms (PHQ-9 ≥ 5) were randomly allocated to SHED-IT: Recharge (n = 62) or wait-list control (n = 63) groups. The self-directed program targeted key health behaviors combined with online mental fitness modules based on cognitive behavioral therapy. Behavioral (e.g., physical activity) and psychological outcomes (e.g., cognitive flexibility) were assessed with validated measures at baseline, 3 months (post-test) and 6 months (follow-up). Intention-to-treat linear mixed models examined treatment effects, which were adjusted for covariates, and effect size estimated (Cohen’s d).

Results

At post-test, intervention men achieved small-to-medium improvements in several health behavior outcomes including moderate-to-vigorous physical activity, light physical activity, sedentary behavior, sleep, energy intake, portion size, and risky alcohol consumption (range, d = 0.3–0.5), when compared with the control group. Intervention effects were also observed for perceived physical self-worth, perceived physical strength, cognitive flexibility, and behavioral activation (range, d = 0.3–0.8). No effects were found for fruit and vegetable intake, or mindful attention. Most effects were maintained at follow-up.

Conclusions

This gender-tailored, eHealth program with integrated mental fitness support elicited meaningful improvements in health behaviors and psychological outcomes for men with low mood.

Trial Registration: Australian New Zealand Clinical Trials Registry (ACTRN12619001209189).
Identification and characterization of a novel class of self-sufficient cytochrome P450 hydroxylase involved in cyclohexanecarboxylate degradation in Paraburkholderia terrae strain KU-64
Authors: Yamamoto Taisei , Hasegawa Yoshie , Iwaki Hiroaki
Published: December 2021

Cytochrome P450 monooxygenases play important roles in metabolism. Here, we report the identification and biochemical characterization of P450CHC, a novel self-sufficient cytochrome P450, from cyclohexanecarboxylate-degrading Paraburkholderia terrae KU-64. P450CHC was found to comprise a [2Fe-2S] ferredoxin domain, NAD(P)H-dependent FAD-containing reductase domain, FCD domain, and cytochrome P450 domain (in that order from the N terminus). Reverse transcription–polymerase chain reaction results indicated that the P450CHC-encoding chcA gene was inducible by cyclohexanecarboxylate. chcA overexpression in Escherichia coli and recombinant protein purification enabled functional characterization of P450CHC as a catalytically self-sufficient cytochrome P450 that hydroxylates cyclohexanecarboxylate. Kinetic analysis indicated that P450CHC largely preferred NADH (Km = 0.011 m m) over NADPH (Km = 0.21 m m). The Kd, Km, and kcat values for cyclohexanecarboxylate were 0.083 m m, 0.084 m m, and 15.9 s−1, respectively. The genetic and biochemical analyses indicated that the physiological role of P450CHC is initial hydroxylation in the cyclohexanecarboxylate degradation pathway.
Efficient gradient boosting for prognostic biomarker discovery
Authors: Li Kaiqiao , Yao Sijie , Zhang Zhenyu , Cao Biwei , Wilson Christopher M , Kalos Denise , Kuan Pei Fen , Zhu Ruoqing , Wang Xuefeng
Published: December 2021

Motivation

A gradient boosting decision tree (GBDT) is a powerful ensemble machine-learning method that has the potential to accelerate biomarker discovery from high-dimensional molecular data. Recent algorithmic advances, such as extreme gradient boosting (XGB) and light gradient boosting (LGB), have rendered the GBDT training more efficient, scalable and accurate. However, these modern techniques have not yet been widely adopted in discovering biomarkers for censored survival outcomes, which are key clinical outcomes or endpoints in cancer studies.

Results

In this paper, we present a new R package ‘Xsurv’ as an integrated solution that applies two modern GBDT training frameworks namely, XGB and LGB, for the modeling of right-censored survival outcomes. Based on our simulations, we benchmark the new approaches against traditional methods including the stepwise Cox regression model and the original gradient boosting function implemented in the package ‘gbm’. We also demonstrate the application of Xsurv in analyzing a melanoma methylation dataset. Together, these results suggest that Xsurv is a useful and computationally viable tool for screening a large number of prognostic candidate biomarkers, which may facilitate future translational and clinical research.

Availability and implementation

‘Xsurv’ is freely available as an R package at: https://github.com/topycyao/Xsurv.

Supplementary information

Supplementary data are available at Bioinformatics online.
Encoding contexts are incidentally reinstated during competitive retrieval and track the temporal dynamics of memory interference
Authors: Bramão Inês , Jiang Jiefeng , Wagner Anthony D , Johansson Mikael
Published: December 2021

The ability to remember an episode from our past is often hindered by competition from similar events. For example, if we want to remember the article a colleague recommended during the last lab meeting, we may need to resolve interference from other article recommendations from the same colleague. This study investigates if the contextual features specifying the encoding episodes are incidentally reinstated during competitive memory retrieval. Competition between memories was created through the AB/AC interference paradigm. Individual word-pairs were presented embedded in a slowly drifting real–word-like context. Multivariate pattern analysis (MVPA) of high temporal-resolution electroencephalographic (EEG) data was used to investigate context reactivation during memory retrieval. Behaviorally, we observed proactive (but not retroactive) interference; that is, performance for AC competitive retrieval was worse compared with a control DE noncompetitive retrieval, whereas AB retrieval did not suffer from competition. Neurally, proactive interference was accompanied by an early reinstatement of the competitor context and interference resolution was associated with the ensuing reinstatement of the target context. Together, these findings provide novel evidence showing that the encoding contexts of competing discrete events are incidentally reinstated during competitive retrieval and that such reinstatement tracks retrieval competition and subsequent interference resolution.
Task-specific network interactions across key cognitive domains
Authors: Williams Kathleen A , Numssen Ole , Hartwigsen Gesa
Published: December 2021

Human cognition is organized in distributed networks in the brain. Although distinct specialized networks have been identified for different cognitive functions, previous work also emphasizes the overlap of key cognitive domains in higher level association areas. The majority of previous studies focused on network overlap and dissociation during resting states whereas task-related network interactions across cognitive domains remain largely unexplored. A better understanding of network overlap and dissociation during different cognitive tasks may elucidate flexible (re-)distribution of resources during human cognition. The present study addresses this issue by providing a broad characterization of large-scale network dynamics in three key cognitive domains. Combining prototypical tasks of the larger domains of attention, language, and social cognition with whole-brain multivariate activity and connectivity approaches, we provide a spatiotemporal characterization of multiple large-scale, overlapping networks that differentially interact across cognitive domains. We show that network activity and interactions increase with increased cognitive complexity across domains. Interaction patterns reveal a common core structure across domains as well as dissociable domain-specific network activity. The observed patterns of activation and deactivation of overlapping and strongly coupled networks provide insight beyond region-specific activity within a particular cognitive domain toward a network perspective approach across diverse key cognitive functions.
Morphological development of the human fetal striatum during the second trimester
Authors: Tian Mimi , Xu Feifei , Xia Qing , Tang Yuchun , Zhang Zhonghe , Lin Xiangtao , Meng Haiwei , Feng Lei , Liu Shuwei
Published: December 2021

The morphological development of the fetal striatum during the second trimester has remained poorly described. We manually segmented the striatum using 7.0-T MR images of the fetal specimens ranging from 14 to 22 gestational weeks. The global development of the striatum was evaluated by volume measurement. The absolute volume (Vabs) of the caudate nucleus (CN) increased linearly with gestational age, while the relative volume (Vrel) showed a quadratic growth. Both Vabs and Vrel of putamen increased linearly. Through shape analysis, the changes of local structure in developing striatum were specifically demonstrated. Except for the CN tail, the lateral and medial parts of the CN grew faster than the middle regions, with a clear rostral–caudal growth gradient as well as a distinct “outside–in” growth gradient. For putamen, the dorsal and ventral regions grew obviously faster than the other regions, with a dorsal–ventral bidirectional developmental pattern. The right CN was larger than the left, whereas there was no significant hemispheric asymmetry in the putamen. By establishing the developmental trajectories, spatial heterochrony, and hemispheric dimorphism of human fetal striatum, these data bring new insight into the fetal striatum development and provide detailed anatomical references for future striatal studies.
Parent-Reported Stress and Child Behavior for 4-Year-Old Children with Unilateral or Mild Bilateral Hearing Loss
Authors: Fitzpatrick Elizabeth M , Jiawen Wu , Janet Olds , JoAnne Whittingham , Flora Nassrallah , Isabelle Gaboury , Andrée Durieux-Smith , Doug Coyle
Published: December 2021

Children with unilateral or mild bilateral hearing loss are increasingly identified in early childhood. Relatively little is known about how hearing loss affects their developmental trajectory or whether it contributes to parenting stress for these parents. This study aimed to examine child behavior and parenting stress in parents of children with unilateral/mild bilateral hearing loss compared to children with typical hearing. This prospective study involved 54 children with unilateral/mild bilateral hearing loss identified at a median age of 4.5 months (IQR 2.6, 6.5) and 42 children with typical hearing. At age 48 months, child behavior and parenting stress were measured. Auditory and language results were also analyzed in relation to child behavior and parenting stress. Parents of these children did not report significantly more parenting stress or behavior problems than parents of children with typical hearing. However, both parenting stress and child behavior were related to functional hearing in noise.
Variability in endoscopic assessment of Nissen fundoplication wrap integrity and hiatus herniation
Authors: Song Erin J , Yadlapati Rena , Chen Joan W , Parish Alice , Whitson Matthew J , Ravi Karthik , Patel Amit , Carlson Dustin A , Khan Abraham , Niedzwiecki Donna , Leiman David A
Published: December 2021

Background

Upper endoscopy (EGD) is frequently performed in patients with esophageal complaints following anti-reflux surgery such as fundoplication. Endoscopic evaluation of fundoplication wrap integrity can be challenging. Our primary aim in this pilot study was to evaluate the accuracy and confidence of assessing Nissen fundoplication integrity and hiatus herniation among gastroenterology (GI) fellows, subspecialists, and foregut surgeons.

Methods

Five variations of post-Nissen fundoplication anatomy were included in a survey of 20 sets of EGD images that was completed by GI fellows, general GI attendings, esophagologists, and foregut surgeons. Accuracy, diagnostic confidence, and inter-rater agreement across providers were evaluated.

Results

There were 31 respondents in the final cohort. Confidence in pre-survey diagnostics significantly differed by provider type (mean confidence out of 5 was 1.8 for GI fellows, 2.7 for general GI attendings, 3.6 for esophagologists, and 3.6 for foregut surgeons, P = 0.01). The mean overall accuracy was 45.9%, which significantly differed by provider type with the lowest rate among GI fellows (37%) and highest among esophagologists (53%; P = 0.01). The accuracy was highest among esophagologists across all wrap integrity variations. Inter-rater agreement was low across wrap integrity variations (Krippendorf’s alpha <0.30), indicating low to no agreement between providers.

Conclusion

In this multi-center survey study, GI fellows had the lowest accuracy and confidence in assessing EGD images after Nissen fundoplication, whereas esophagologists had the highest. Diagnostic confidence varied considerably and inter-rater agreement was poor. These findings suggest experience may improve confidence, but highlight the need to improve the evaluation of fundoplication wraps.
Do Options Matter? Settling Behavior, Stylet Sheath Counts, and Oviposition of Aster Leafhoppers (Hemiptera: Cicadellidae) in Two-Choice Bioassays
Authors: Romero Berenice , Olivier Chrystel , Wist Tyler , Prager Sean M
Published: December 2021

Polyphagous insects are characterized by a broad diet comprising plant species from different taxonomic groups. Within these insects, migratory species are of particular interest, given that they encounter unpredictable environments, with abrupt spatial and temporal changes in plant availability and density. Aster leafhoppers (Hemiptera: Cicadellidae: Macrosteles quadrilineatus Forbes) arrive in the Canadian Prairies in spring and early summer and are the main vector of a prokaryotic plant pathogen known as Aster Yellows Phytoplasma (AYp) (Candidatus Phytoplasma asteris). Host choice selection behavior of Aster leafhoppers was evaluated through two-choice bioassays, using domesticated and wild plants species commonly found in the Canadian Prairies. Leaf tissues from these plants were collected and stained to quantify the number of stylet sheaths and eggs. To assess possible effects due to insect infection, two-choice bioassays were repeated using leafhoppers infected with AYp and a subset of plant species. When two domesticated or wild plant species were presented together, similar numbers of uninfected Aster leafhoppers were observed on both plant species in most combinations. In domesticated–wild plant bioassays, uninfected Aster leafhoppers preferred to settle on the domesticated species. There was little to no association between settling preferences and stylet sheath and egg counts. These findings provide a better understanding of AY epidemiology and suggest that after domesticated species germination, leafhoppers could move from nearby wild plants into the preferred cereals (Poales: Poaceae) to settle on them, influencing the risk of AYp infection in some of these species.
COVID-19 and postural tachycardia syndrome: a case series
Authors: Parker William H , Moudgil Rohit , Wilson Robert G , Tonelli Adriano R , Mayuga Kenneth A , Singh Tamanna K
Published: December 2021

Background

Postural tachycardia syndrome (PTS) is a novel identified sequela of COVID-19 infection. This observational study describes clinical presentation, testing, and treatment response in seven patients diagnosed with PTS following COVID-19 infection.

Case summary

A total of seven active patients (three collegiate athletes, one recreational athlete, two registered nurses, one hospitality employee), age 24 ± 6 years, and six females were followed for a mean of 152 ± 105 days after contracting COVID-19. Tilt table was performed to establish the diagnosis. The most common presenting symptoms were palpitations (7/7), dyspnoea (6/7), and gastrointestinal complaints (5/7). One patient required hospitalization for symptom management. The mean latency of PTS onset following COVID-19 was 21 ± 15 days. Electrocardiograms (ECGs) demonstrated sinus rhythm in all patients, one with resting sinus tachycardia. Echocardiogram demonstrated normal systolic and diastolic left ventricular function in all patients. On tilt table testing, baseline heart rate (HR) was 72 ± 12 with maximum HR reaching 136 ± 13. Six of seven patients failed to respond to supportive therapy alone, and two patients failed medical management with ivabradine, midodrine, and/or metoprolol. Of three severely symptomatic patients, two demonstrated some degree of clinical recovery with intravenous immunoglobulin (IVIG).

Discussion

This novel case series describes the development of PTS in the context of COVID-19 infection. Severity of symptoms and response to treatment was heterogeneous. Interestingly, patients were poorly responsive to traditional PTS treatments, but IVIG showed potential as a possible therapeutic strategy for refractory PTS in two patients, particularly following COVID-19 infection.
Quantifying preload alterations using a sensitive chest-mounted accelerometer
Authors: Schmidt S E , Kristensen C B , Soerensen K , Soegaard P , Mogelvang R
Published: December 2021

Seismocardiography (SCG) is a technology where the chest wall vibrations from the beating heart are measured using a highly sensitive accelerometer. SCG offers continuous measurement of cardiac function and potential applications include remote monitoring, diagnostic assessments, prognostic health checks and biventricular pacemaker optimization.

Aim

In the current study we examined how changes in preload influence SCG time intervals, by acute saline infusion.

Methods

We included twenty-six subjects, sixteen subjects with cardiac disease such as hypertrophic cardiomyopathy, dilated cardiomyopathy, aortic valve disease or ischemic heart disease (age 45.8±17.7 years and 93% male) and ten subjects without known cardiac conditions (age 42.1±14.4 years and 70% male). SCG was recorded from the xiphoid process using a custom-made sensor before and after acute infusion saline (median 2.0 L). The SCG signals were sampled with 5000 samples per second in 60 seconds, the individual heartbeats were identified using a dedicated segmentation algorithm and an average SCG beat was computed and used for the data analysis. Using a recently proposed nomenclature the following SCG fiducial points was identified: Es which coinciding with mitral valve closure, Gs which to some degree coincides with aortic opening, Bd coinciding with aortic valve closure and Fd coinciding with mitral valve opening [1]. The Es-Gs time interval was used as a measure of isovolumetric contraction time (IVCT), the Gs-Bd time interval was used as an estimate of ejection time (ET) and the Bd-Fd time interval as an estimate of isovolumetric relaxation time (IVRT). Paired t-test was used to test for significant response after infusion, while a two sample t-test was used to test for a significant difference in the observed response in subjects with or with our cardiac disease.

Results

For two subjects SCG after infusion was not obtained thus, twenty-four subjects were included in the final data analysis. In the whole group, acute saline infusion shortened the IVRT (Bd-Fd) from 91.0±15.3 ms to 82.7±15.3 ms (p=0.004) and prolonged the ET (Gs-Bd) from 329.4±35 ms to 343.4±33 ms (p<0.001). There was no significant change in IVCT (Es-Gs) which was 39.5±15.1 ms at baseline and 38.1±14.9 ms post-infusion (p=0.88). There was no significant difference in response between subjects with or without cardiac disease.

Conclusion

Increase in preload shortened the SCG time intervals related to the isovolumetric relaxation period and prolonged the period related to ejection time. SCG time intervals capture changes in preload, which demonstrates that the SCG is a potential modality for quantification of cardiac dynamics.

Funding Acknowledgement

Type of funding sources: None.