bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Evaluation of Dielectric Losses of PPLP for Single Phase HTS Cable at Subcooled LN2
Temperatures
Authors: Sarkar Maalika , de Souza I , Sarkar A , Gour A S , Rao V V
Published: June 2022

For the operation of high-temperature superconducting (HTS) power cables in liquid nitrogen (LN2
) at high voltage levels, there is a need for reliable and cost-effective insulating materials. This article investigates the dielectric losses in poly-propylene laminated paper (PPLP- Sumitomo) which is used as a cold dielectric for HTS cables. To calculate the dielectric losses, an experimental setup was developed to measure the relative permittivity of PPLP at different temperatures from 65 to 300 K at various frequencies. Using an in-house developed experimental setup, the dielectric loss for different layers of PPLP, at various temperatures and operating frequencies was estimated to evaluate one of the criteria of cold dielectric material and the same was compared with the data at room temperature. The temperature was reduced to 65 K using a vacuum pump-assisted sub-cooling system. The effective relative permittivity increases marginally for subcooled LN2
impregnated PPLP, however there is reduction in tan delta loss which in turn reduces the dielectric loss and is useful for high voltage HTS based AC cables. This paper provides a comparative study on PPLP performance variation with respect to operating temperature and frequency.
Thermal conductivity of niobium and thermally sprayed copper at cryogenic temperature
Authors: Fouaidy M.
Published: June 2022

We have developed a test facility dedicated to thermal conductivity k(T) measurements at low temperature. These experimental devices allow the test of four samples simultaneously during each run. The measurements are performed using steady-state axial heat flow method with a careful control of heat leaks to the surrounding. The apparatus was successfully used for measuring k(T) (Temperature T in the range: 1.5 K - 10 K) of niobium and other materials used for the fabrication of Superconducting Radio Frequency (SRF) cavities. We have tested the following samples: 1) niobium samples from different supplier (as received or/and after various high temperature Heat Treatments (HT)), 2) thermally sprayed copper coatings. The resulting experimental data are presented and compared to the experimental results previously reported by other groups and theoretical values. As expected heat treatment have a strong impact on k(T) and in particular on the phonons peak at T∼2K. More precisely, HT @ 1200°C with Ti gettering improves the Nb Residual Resistance Ratio (RRR) by a factor of 3 and consequently k(T). Finally, the correlation between the niobium RRR and the thermal conductivity. at T=4.2 K is confirmed in good agreement with the Wiedemann-Franz law
Fatigue life characterization of hand folded and vacuum formed Kresling origami bellows at 77K
Authors: Dunne Francis , Westra Kjell , Mattox Caleb , Leachman Jacob
Published: June 2022

Propellant migration in microgravity is a critical challenge for in-space fuel storage and transfer. Origami fuel bladders are a new design solution to prevent cracking in polymeric materials within the cryogenic regime. This paper explores manufacturing techniques for producing origami bladders as well as the limits of possible thicknesses for origami bladders. Origami bladders are manufactured from polyvinylidene fluoride (PVDF) and polyethylene terephthalate glycol (PETG). Hand folded bladders follow a Kresling bellows origami pattern while the thermoformed samples are prepared using a mold of the Kresling bellows and an EZFORM LV 1827 thermoformer is used to shape the polymeric film. Compressive fatigue testing is carried out within liquid nitrogen to confirm the sample can survive deformation at cryogenic temperatures. Hand folded origami bellows specimens survived 3300+ cycles with minimal signs of degradation, while similar PVDF specimens cracked in fewer than 10 cycles.
Current sharing and stability in an extremely low AC-loss MgB2 conductor
Authors: Kovacs C J , Haugan T J , Sumption M D , Tomsic M , Rindfleisch M
Published: June 2022

In the push to develop high power electric aircraft, superconducting technology promises to significantly reduce mass and volume of motors and generators. However, challenges related to AC-loss and thermal management are a significant factor in preventing the proliferation of aerospace superconducting technologies. Increasing the resistance of the metal matrix stabilization has only gone so far in reducing coupling currents for higher frequency applications. In this research, Multiphysics simulations of a single composite filament were used to investigate stability decreases when using very high thermal conductivity electrical insulator (CsI) or metal-to-insulator transitioning material (V2O3) to replace the slightly resistive metal matrix typically used for a low AC loss MgB2 composite wire. The insulators separate the MgB2 filaments entirely, only allowing transient current sharing to occur with the high purity Nb diffusion barrier or with the metallic state V2O3. These simulations show that for these very low AC-loss composites at 20 K, instability will become a major issue due to reductions in current sharing. With higher electrical conductivity metal-to-insulator materials, higher thermal conductivity impregnation materials, and thicker metallic diffusion barriers it may be possible to find a reasonable balance between AC-loss and stability.
Mechanical stability of SIS100 Bypass Line busbars clamping system under AC current load
Authors: Iluk A , Chorowski M , Poliński J , Eisel T , Streicher B , Trockel R , Grzegory P
Published: June 2022

This paper presents the lessons learned from tests of first module of superconducting cryogenic bypass line (BPL), a part of the international Facility for Antiproton and Ion Research (FAIR) SIS100 cryogenic system, currently under construction in Darmstadt, Germany. Design, manufacturing, and installation of the superconducting cryogenic bypass line is a part of a Polish in-kind contribution to the FAIR project, realized by the Wroclaw University of Science and Technology. The main goal of the tests was to check the superconducting, Nuclotron type busbar system containing four pairs of busbars, transferring 13.2 kA pulsing current with the ramp rate of 28 kA/s. The mechanical stability of the busbars, especially at the connection region, was investigated with the use of vibration sensors and cameras located inside the vacuum space. The tests revealed insufficient mechanical stability of the busbars in the connection area due to pulsing Lorentz forces, and necessity of additional supports and clamps. Results of the tests were presented and discussed. The conclusions can be significant not only for the bypass line design, but also for design of the busbar connections in the superconducting magnets.
Development of Arduino Based Power Conditioning Unit for Superconducting Magnetic Energy Storage (SMES) System used as UPS for Load Leveling during Charging of Electric Vehicles
Authors: Sarkar A , Anand A , Datta T S , Gour A S , Rao V V
Published: June 2022

With the advancements in Electric Vehicle (EV) technology, more and more EVs are entering into service and simultaneously the number of charging stations are also increasing. These charging stations are connected to the EVs for a small duration of time. Hence, as the number of EVs increases, the simultaneous charging of multiple EVs generates a peak active power demand for this duration. The available peak load compensation technologies such as fywheel storage, pumped hydro storage or Battery Energy Storage System (BESS) take a long time to respond and are not very efcient. With an operational efciency exceeding 90 % and quick reaction time (< 1 second), a Superconducting Magnetic Energy Storage (SMES) system can be a viable solution for this scenario. A SMES system generally consists of a superconducting coil system being charged during the low load/no load period and discharged during the peak demand, with the help of a power conditioning unit (PCU). This paper describes the development of various sub-systems of the SMES-PCU, such as a three-phase rectifer, bidirectional chopper unit, three-phase inverter and the controllers with a description of various modes of operation and sizing of components. The paper also includes the simulation of overall SMES-PCU with suitable assumptions, to present the operational characteristics of the integrated system.
Comparative evaluation of different DC-AC converter topologies for cryogenic applications utilizing superconducting materials
Authors: Ul Hassan M , Emon A I , Azadeh Y , Luo F
Published: June 2022

Modern transportation applications including electric vehicles (EVs), more electric aircraft (MEA) and electric comprise of different power conversion systems. Reduced weight and improved semiconductor efficiency are the major challenges towards their improved overall performance. To overcome them, cryogenic operation of power electronics converters (CPEC), electric motors, cables, and energy storage components has been under research and evaluation. CPEC are being investigated to drive superconducting machines (SCM) because of their lightweight structure and improved efficiency. CPEC can offer improved switching performance, reduced conduction losses and therefore increased efficiency; because of reduced on-resistance and increased carrier mobility of active devices. This article will discuss how can the benefits of lower operating temperature (< 93 K) be utilized in determining the most suitable DC-AC converter configuration. The paper compares three basic converter topologies: (a) two level voltage source inverter (2L-VSI), (b) three level t-type neutral point clamped inverter (3L-TNPC) and (c) two-level current source inverter (2L-CSI). Analysis is provided based on volume of passive components, electromagnetic interference (EMI) spectra and number of active devices, where all components considered are compatible with low temperatures. It can be observed that utilization of cryogenic temperature affects the volume of passive components, and therefore the overall selection of converter.
Influence of magnetron sputtering process parameters on low-temperature electrical transport characteristics of zirconium oxynitride thin films
Authors: Sun X M , Bai X B , Chen F C , Huang R J , Yuan J , Jin K , Su H J , Li L F
Published: June 2022

In order to determine the influence of process parameters including nitrogen and oxygen flow rate on the structure and electrical transport characteristics of zirconium oxynitride(ZrOxNy) thin films, the ZrOxNy films were prepared on sapphire substrates by RF reactive magnetron sputtering deposition technology. The crystal orientation and morphology of ZrOxNy films prepared at different nitrogen and oxygen flow rate were characterized by XRD and SEM, respectively. The electric transport behavior of ZrOxNy films at 300K to 3K was measured by PPMS. The results show that the insulativity of ZrN films is enhanced with the increase of nitrogen flow rate in sputtering atmosphere. With the increase of oxygen flow rate in sputtering atmosphere, the insulativity of ZrOxNy film is enhanced.
Experimental and numerical simulation study of the effect for the anode positions on the discharge characteristics of 300 W class low power Hall thrusters
Authors: CHEN 陈 Xinwei 新伟 , GAO 高 Jun 俊 , YANG 杨 Sanxiang 三祥 , GENG 耿 Hai 海 , GUO 郭 Ning 宁 , GU 顾 Zuo 左 , YANG 杨 Juntai 俊泰 , ZHANG 张 Hong 宏
Published: June 2022

Low-power Hall thruster (LHT) generally has poor discharge efficiency characteristics due to the large surface-to-volume ratio. Aiming to further refine and improve the performance of 300 W class LHT in terms of thrust and efficiency, and to obtain the most optimal operating point, the experimental study of the discharge characteristics for three different anode positions was conducted under the operation of various discharge voltages (100–400 V) and anode mass flow rates (0.65 mg·s−1 and 0.95 mg·s−1). The experimental results indicated that the thruster has the most excellent performance in terms of thrust and efficiency etc at a channel length of 27 mm for identical operating conditions. In addition, particle in cell simulations, employed to reveal the underlying physical mechanisms, show that the ionization and acceleration zone is pushed downwards towards the channel exit as the anode moves towards the exit. At the identical operating point, when the channel length is reduced from 32 to 27 mm, the ionization and acceleration zone moves towards the exit, and the parameters such as thrust and efficiency increase due to the high ionization rate, ion number density, and axial electric field. When the channel length is further moved to 24 mm, the parameters in terms of thrust (F) and efficiency (

η

a

) are reduced as a result of the decreasing ionization efficiency (

η

m

) and the larger plume divergence angle (

α

). In this paper, the results indicated that an optimum anode position (

Δ
L
=
27

mm) exists for the optimum performance.
The curvature effect in Gaussian random fields
Authors: Levada Alexandre L M
Published: June 2022

Random field models are mathematical structures used in the study of stochastic complex systems. In this paper, we compute the shape operator of Gaussian random field manifolds using the first and second fundamental forms (Fisher information matrices). Using Markov chain Monte Carlo techniques, we simulate the dynamics of these random fields and compute the Gaussian, mean and principal curvatures of the parametric space, analyzing how these quantities change along dynamics exhibiting phase transitions. During the simulations, we have observed an unexpected phenomenon that we called the curvature effect, which indicates that a highly asymmetric geometric deformation happens in the underlying parametric space when there are significant increase/decrease in the system’s entropy. When the system undergoes a phase transition from randomness to clustered behavior the curvature is smaller than that observed in the reverse phase transition. This asymmetric pattern relates to the emergence of hysteresis phenomenon, leading to an intrinsic arrow of time along the random field dynamics.
Amplified graph C*-algebras II: Reconstruction
Authors: Eilers Søren , Ruiz Efren , Sims Aidan
Published: June 2022

Let

E
E

be a countable directed graph that is amplified in the sense that whenever there is an edge from

v
v

to

w
w

, there are infinitely many edges from

v
v

to

w
w

. We show that

E
E

can be recovered from

C
∗

(
E
)

C^*(E)

together with its canonical gauge-action, and also from

L

K

(
E
)

L_\mathbb {K}(E)

together with its canonical grading.
Dynamical behavior of almost periodically forced neutral delayed equation and its applications
Authors: Zhou Hui
Published: June 2022

In this paper, we consider a class of almost periodically forced neutral delayed equation, which arises from population model with delays. A threshold parameter in terms of basic reproduction ratio

R
0

R_0

is introduced into this neutral system. We derive the strongly subhomonogenous property of skew-product semiflow generated by the linearized neutral system under the assumptions of non-neutral case. We show that the positive almost periodic solution is globally stable by applying the approach of monotone skew-product semiflow. Finally, as a classical example, we illustrate the asymptotic behavior of Nicholson model with neutral type delays by using of the new theoretical results. The dynamical behaviors of neutral delayed equation forced by almost periods in this paper cover automatically some known ones of the non-neutral cases.
Reading Mozambique’s mega-project developmentalism through the workplace: evidence from Chinese
and Brazilian investments
Authors: Cezne Eric , Wethal Ulrikke
Published: June 2022

Propelled by a commodities boom and expanding South–South investment, mega-projects have reshaped the politics of labour in many African settings. Reflecting on such dynamics, this article critically engages with questions of employment, skills development, and contestation re-configuring capital–labour encounters in the ‘Chinese’ and ‘Brazilian’ workplace in Mozambique. We analyse two mega-projects: the Maputo Ring Road, implemented by the China Road and Bridge Corporation, and the Moatize Coal Project, led by the Brazilian mining company, Vale SA. Engaging with the complex realities at project ground level, the article unpacks how workplace regimes and outcomes reflect an intricate, multi-scalar array of spatial encounters, sector-specific characteristics, and national political economies. For both cases, this is associated with common promises of development and prosperity for Mozambique. While such promises take on different ideational guises, we show that the Chinese and Brazilian workplaces expose, nonetheless, overlapping patterns of inequality, contention, and hostility, reinforced by broader vulnerabilities and imbalances in global production networks and the Mozambican political economy. By providing a ground-level reading of the multi-scalar forces at play in the workplace, this article sheds light on the relationship between emerging South–South global encounters, national political realities, and labour geographies in African contexts shaped by mega-projects.
In vitro colonic fermentation characteristics of barley-koji differ from those of barley
Authors: Nagata Ryuji , Morioka Minami , Fukuma Naoki , Hayashi Kei , Iwami Akihiko , Han Kyu-Ho , Fukushima Michihiro
Published: June 2022

Barley-koji is prepared by inoculating barley, a beneficial prebiotic source, with the fungi Aspergillus luchuensis mut. kawachii. In this study, the prebiotic effects of barley-koji on human colonic microbiota were evaluated in vitro compared with barley, using pig feces. The enzyme-resistant fraction of the following sample groups each was added to respective fermenters: cellulose, barley (Commander and β104), and barley-koji (Commander-koji and β104-koji). Short-chain fatty acid and ammonia-nitrogen production increased and decreased, respectively, in barley-koji and barley groups. Furthermore, the propionate concentration increased in the barley group, showing a positive correlation with the abundance of the genus Dialister. In the barley-koji group, however, acetate and n-butyrate concentrations increased during the early stages of incubation, and the relative abundance of the genus Megasphaera was higher than those of the other genera. Therefore, this study demonstrated that barley-koji might possess beneficial physiological properties for colonic fermentation, which differ from those of barley.
Mapping developmental paths of monkey primordial germ-like cells differentiation from pluripotent stem cells by single cell ribonucleic acid sequencing analysis
Authors: Zhang Puyao , Xue Sengren , Guo Rongrong , Liu Jian , Bai Bing , Li Dexuan , Hyraht Ahjol , Sun Nianqin , Shao Honglian , Fan Yong , Ji Weizhi , Yang Shihua , Yu Yang , Tan Tao
Published: June 2022

The induction of primordial germ-like cells (PGCLCs) from pluripotent stem cells (PSCs) provides a powerful system to study the cellular and molecular mechanisms underlying germline specification, which are difficult to study in vivo. The studies reveal the existence of a species-specific mechanism underlying PGCLCs between humans and mice, highlighting the necessity to study regulatory networks in more species, especially in primates. Harnessing the power of single-cell RNA sequencing (scRNA-seq) analysis, the detailed trajectory of human PGCLCs specification in vitro has been achieved. However, the study of nonhuman primates is still needed. Here, we applied an embryoid body (EB) differentiation system to induce PGCLCs specification from cynomolgus monkey male and female PSCs, and then performed high throughput scRNA-seq analysis of approximately 40 000 PSCs and cells within EBs. We found that EBs provided a niche for PGCLCs differentiation by secreting growth factors critical for PGCLC specification, such as bone morphogenetic protein 2 (BMP2), BMP4, and Wnt Family Member 3. Moreover, the developmental trajectory of PGCLCs was reconstituted, and gene expression dynamics were revealed. Our study outlines the roadmap of PGCLC specification from PSCs and provides insights that will improve the differentiation efficiency of PGCLCs from PSCs.
‘Villagers in the City’: Resilience in migrant youth amidst urbanisation
Authors: Lu Shuang
Published: June 2022

Rapid urbanisation necessitates more research attention to the challenges and resources among families moving from rural to urban areas. Using a multisystemic resilience framework, this qualitative study explores how resilience is embodied in the intrapersonal, interpersonal and institutional levels of the daily lives of migrant children in China, an exemplar of contemporary fast-urbanising societies. I conducted semi-structured in-depth interviews with ten migrant children who live in Beijing, along with their parents, teachers and social service providers. The findings suggest that rural-to-urban migration is both an empowering and a depriving experience. On the intrapersonal level, migration increases children’s independence, personal growth, future aspirations, as well as academic stress. On the interpersonal level, migrant children receive substantial support from parents, siblings, extended family and peers; however, they are at risk of insufficient parental supervision and loss of meaningful relationships. On the institutional level, migration provides children with a better environment, better school experiences, greater material resources and social organisation services, but migrant children remain vulnerable to educational discrimination, economic deprivation and poor neighbourhood environments in the city.
The AHNAK induces increased IL-6 production in CD4+ T cells and serves as a potential diagnostic biomarker for recurrent pregnancy loss
Authors: Li Liman , Liu Yuan , Feng Ting , Zhou Wenjie , Wang Yanyun , Li Hong
Published: June 2022

Disorganized maternal–fetal immune tolerance contributes to the occurrence of unexplained recurrent pregnancy loss (RPL). AHNAK is a scaffolding protein participating in the regulation of Ca2+ entry into T cells and the pathophysiology of diverse diseases. We performed differential gene expression analysis in decidual immune cells (DICs) isolated from three patients with RPL and from three healthy controls via RNA-sequencing (RNA-seq), which revealed 407 differentially expressed genes (DEGs). Among these DEGs, we underscored the clinical significance of elevated AHNAK mRNA and protein levels in DICs, peripheral blood mononuclear cells (PBMCs), and decidua of the patients with RPL, suggesting its potential use as a biomarker for the diagnosis of RPL. Especially, the ratios of decidual and blood AHNAK+CD4+ T cells in the CD4+ T cell population were significantly increased in patients with RPL, and the loss of AHNAK was further shown to inhibit interleukin (IL)-6 secretion in the CD4+ Jurkat cell line. Similar patterns were also observed in the clinical decidual and blood specimens. We uncovered that the AHNAK+CD4+ T cells could secrete more IL-6 than that the corresponding AHNAK-CD4+ T cells. Moreover, the frequencies of decidual and blood IL-6+CD4+ T cells in the CD4+ T-cell population were also increased in patients with RPL and showed significant positive correlations with the frequencies of AHNAK+CD4+ T cells. Our findings suggest that the elevated AHNAK expressed by CD4+ T cells may be involved in the immune dysregulation of RPL by increasing IL-6 production, illustrating its potential as a novel intervention target for RPL.
Arrhythmic risk prediction in arrhythmogenic right ventricular cardiomyopathy: external validation of the arrhythmogenic right ventricular cardiomyopathy risk calculator
Authors: Jordà Paloma , Bosman Laurens P , Gasperetti Alessio , Mazzanti Andrea , Gourraud Jean Baptiste , Davies Brianna , Frederiksen Tanja Charlotte , Weidmann Zoraida Moreno , Di Marco Andrea , Roberts Jason D , MacIntyre Ciorsti , Seifer Colette , Delinière Antoine , Alqarawi Wael , Kukavica Deni , Minois Damien , Trancuccio Alessandro , Arnaud Marine , Targetti Mattia , Martino Annamaria , Oliviero Giada , Pipilas Daniel C , Carbucicchio Corrado , Compagnucci Paolo , Dello Russo Antonio , Olivotto Iacopo , Calò Leonardo , Lubitz Steven A , Cutler Michael J , Chevalier Philippe , Arbelo Elena , Priori Silvia Giuliana , Healey Jeffrey S , Calkins Hugh , Casella Michela , Jensen Henrik Kjærulf , Tondo Claudio , Tadros Rafik , James Cynthia A , Krahn Andrew D , Cadrin-Tourigny Julia
Published: June 2022

Aims

Arrhythmogenic right ventricular cardiomyopathy (ARVC) causes ventricular arrhythmias (VAs) and sudden cardiac death (SCD). In 2019, a risk prediction model that estimates the 5-year risk of incident VAs in ARVC was developed (ARVCrisk.com). This study aimed to externally validate this prediction model in a large international multicentre cohort and to compare its performance with the risk factor approach recommended for implantable cardioverter-defibrillator (ICD) use by published guidelines and expert consensus.

Methods and results

In a retrospective cohort of 429 individuals from 29 centres in North America and Europe, 103 (24%) experienced sustained VA during a median follow-up of 5.02 (2.05–7.90) years following diagnosis of ARVC. External validation yielded good discrimination [C-index of 0.70 (95% confidence interval-CI 0.65–0.75)] and calibration slope of 1.01 (95% CI 0.99–1.03). Compared with the three published consensus-based decision algorithms for ICD use in ARVC (Heart Rhythm Society consensus on arrhythmogenic cardiomyopathy, International Task Force consensus statement on the treatment of ARVC, and American Heart Association guidelines for VA and SCD), the risk calculator performed better with a superior net clinical benefit below risk threshold of 35%.

Conclusion

Using a large independent cohort of patients, this study shows that the ARVC risk model provides good prognostic information and outperforms other published decision algorithms for ICD use. These findings support the use of the model to facilitate shared decision making regarding ICD implantation in the primary prevention of SCD in ARVC.
Association between hypotension during 24 h ambulatory blood pressure monitoring and reflex syncope: the SynABPM 1 study
Authors: Rivasi Giulia , Groppelli Antonella , Brignole Michele , Soranna Davide , Zambon Antonella , Bilo Grzegorz , Pengo Martino , Sharad Bashaaer , Hamrefors Viktor , Rafanelli Martina , Testa Giuseppe Dario , Rice Ciara , Kenny Rose Anne , Sutton Richard , Ungar Andrea , Fedorowski Artur , Parati Gianfranco
Published: June 2022

Aims

Diagnostic criteria for ambulatory blood pressure monitoring (ABPM) in patients with suspected reflex syncope are lacking. The study hypothesis was that patients with reflex syncope have a higher prevalence of systolic blood pressure (SBP) drops on ABPM.

Methods and results

ABPM data from reflex syncope patients and controls, matched by average 24 h SBP, age, sex, and hypertension were compared. Patients with constitutional hypotension, orthostatic hypotension, and predominant cardioinhibition during carotid sinus massage or prolonged electrocardiogram monitoring or competing causes of syncope were excluded. Daytime and nighttime SBP drops (<110, 100, 90, 80 mmHg) were assessed. Findings were validated in an independent sample. In the derivation sample, daytime SBP drops were significantly more common in 158 syncope patients than 329 controls. One or more daytime drops <90 mmHg achieved 91% specificity and 32% sensitivity [odds ratio (OR) 4.6, P < 0.001]. Two or more daytime drops <100 mmHg achieved 84% specificity and 40% sensitivity (OR 3.5, P = 0.001). Results were confirmed in the validation sample of 164 syncope patients and 164 controls: one or more daytime SBP drops <90 mmHg achieved 94% specificity and 29% sensitivity (OR 6.2, P < 0.001), while two or more daytime SBP drops <100 mmHg achieved 83% specificity and 35% sensitivity (OR 2.6, P < 0.001)

Conclusion

SBP drops during ABPM are more common in reflex syncope patients than in controls. Cut-off values that may be applied in clinical practice are defined. This study expands the current indications for ABPM to patients with reflex syncope.
Divergent gut microbiota in two closely related house mouse subspecies under common garden conditions
Authors: Bendová Barbora , Mikula Ondřej , Vošlajerová Bímová Barbora , Čížková Dagmar , Daniszová Kristina , Ďureje Ľudovít , Hiadlovská Zuzana , Macholán Miloš , Martin Jean-Francois , Piálek Jaroslav , Schmiedová Lucie , Kreisinger Jakub
Published: June 2022

The gastrointestinal microbiota (GM) is considered an important component of the vertebrate holobiont. GM–host interactions influence the fitness of holobionts and are, therefore, an integral part of evolution. The house mouse is a prominent model for GM–host interactions, and evidence suggests a role for GM in mouse speciation. However, previous studies based on short 16S rRNA GM profiles of wild house mouse subspecies failed to detect GM divergence, which is a prerequisite for the inclusion of GM in Dobzhansky–Muller incompatibilities. Here, we used standard 16S rRNA GM profiling in two mouse subspecies, Mus musculus musculus and M. m. domesticus, including the intestinal mucosa and content of three gut sections (ileum, caecum, and colon). We reduced environmental variability by sampling GM in the offspring of wild mice bred under seminatural conditions. Although the breeding conditions allowed a contact between the subspecies, we found a clear differentiation of GM between them, in all three gut sections. Differentiation was mainly driven by several Helicobacters and two H. ganmani variants showed a signal of codivergence with their hosts. Helicobacters represent promising candidates for studying GM–host coadaptations and the fitness effects of their interactions.
A chromosome-level genome assembly and intestinal transcriptome of Trypoxylus dichotomus (Coleoptera: Scarabaeidae) to understand its lignocellulose digestion ability
Authors: Wang Qingyun , Liu Liwei , Zhang Sujiong , Wu Hong , Huang Junhao
Published: June 2022

Lignocellulose, as the key structural component of plant biomass, is a recalcitrant structure, difficult to degrade. The traditional management of plant waste, including landfill and incineration, usually causes serious environmental pollution and health problems. Interestingly, the xylophagous beetle, Trypoxylus dichotomus, can decompose lignocellulosic biomass. However, the genomics around the digestion mechanism of this beetle remain to be elucidated. Here, we assembled the genome of T. dichotomus, showing that the draft genome size of T. dichotomus is 636.27 Mb, with 95.37% scaffolds anchored onto 10 chromosomes. Phylogenetic results indicated that a divergent evolution between the ancestors of T. dichotomus and the closely related scarabaeid species Onthophagus taurus occurred in the early Cretaceous (120 million years ago). Through gene family evolution analysis, we found 67 rapidly evolving gene families, within which there were 2 digestive gene families (encoding Trypsin and Enoyl-(Acyl carrier protein) reductase) that have experienced significant expansion, indicating that they may contribute to the high degradation efficiency of lignocellulose in T. dichotomus. Additionally, events of chromosome breakage and rearrangement were observed by synteny analysis during the evolution of T. dichotomus due to chromosomes 6 and 8 of T. dichotomus being intersected with chromosomes 2 and 10 of Tribolium castaneum, respectively. Furthermore, the comparative transcriptome analyses of larval guts showed that the digestion-related genes were more commonly expressed in the midgut or mushroom residue group than the hindgut or sawdust group. This study reports the well-assembled and annotated genome of T. dichotomus, providing genomic and transcriptomic bases for further understanding the functional and evolutionary mechanisms of lignocellulose digestion in T. dichotomus.
Moho depths for Antarctica Region by the inversion of ground-based gravity data
Authors: Borghi Alessandra
Published: June 2022

In the last years the scientific literature has been enriched with new models of the Moho depth in the Antarctica Continent derived by the seismic reflection technique and refraction profiles, receiver functions and seismic surface waves, but also by gravimetric observations over the continent. In particular, the gravity satellite missions of the last two decades have provided data in this remote region of the Earth and have allowed the investigation of the crust properties. Meanwhile, other important contributions in this direction has been given by the fourth International Polar Year (IPY, 2007–2008) which started seismographic and geodetic networks of unprecedented duration and scale, including airborne gravimetry over largely unexplored Antarctic frontiers. In this study, a new model for the Antarctica Moho depths is proposed. This new estimation is based on no satellite gravity measures, thanks to the availability of the gravity database ANTGG2015, that collects gravity data from ground-base, airborne and shipborne campaigns. In this new estimate of the Moho depths the contribution of the gravity measures has been maximized reducing any correction of the gravity measures and avoiding constraints of the solution to seismological observations and to geological evidence. With this approach a pure gravimetric solution has been determined. The model obtained is pretty in agreement with other Moho models and thanks to the use of independent data it can be exploited also for cross-validating different Moho depths solutions.
Imprints of subducted Palaeo-Tethys oceanic lithosphere on upper-mantle discontinuities and the formation of the Emeishan large igneous province
Authors: He Chuansong
Published: June 2022

Generally, the upwelling of a mantle plume is suggested to have led to the formation of the Emeishan large igneous province (ELIP). However, this idea has been challenged by recent geological and seismological studies. In this investigation, three profiles of velocity perturbations crossing the ELIP are drawn following previous tomographic studies, and common conversion point (CCP) stacking of receiver functions in the ELIP is carried out. A slab-like high-velocity structure is revealed, which may be associated with the lithosphere of the Palaeo-Tethys Ocean (LPTO) subducting toward the northeast. CCP stacking of receiver functions shows that the LPTO generated imprints on the 410- and 660-km discontinuities. A comprehensive analysis suggests that the LPTO may have induced large-scale mantle upwelling, which contributed to the formation of the ELIP.
O-050 Vulnerability of human preimplantation embryos to SARS-CoV-2 infection
Authors: Viotti M
Published: June 2022

Presence of SARS-CoV-2, the virus responsible for COVID-19, has been reported in numerous organs and tissues of infected patients, including the reproductive system. The effects of COVID-19 on human reproduction remain poorly understood. While cases of intrauterine transmission between expectant mother and fetus have been documented, the impact of SARS-CoV-2 infection on early embryogenesis and establishment of a pregnancy are not known. This prompted us to ask if SARS-CoV-2 can infect embryos, since such an event could impact embryo viability and affect a subsequent pregnancy. We used a three-pronged approach to investigate this possibility: 1) Using RNA-seq and immunofluorescence, we learned that ACE2 and TMPRSS2, two factors required on target cells for SARS-CoV-2 entry, are co-expressed in cells of the trophectoderm in blastocyst-stage preimplantation embryos; 2) Using fluorescent reporter virions pseudotyped with Spike (S) glycoprotein from SARS-CoV-2, we observed robust infection of trophectoderm cells, and this permissiveness could be attenuated with blocking antibodies targeting S or ACE2; and 3) Exposing human blastocysts to live, fully infectious SARS-CoV-2, we detected cases of infection that compromised embryo health. Therefore, we identify a new human target tissue for SARS-CoV-2 with potential medical implications for reproductive health during the COVID-19 pandemic and its aftermath.
O-312 Does infertility relate to Human Leucocyte Antigen similarity? – a genetic analysis based on 609 couples
Authors: Goehring D , Goeckenjan M , Göhring I , Sauter J , Schmidt A , Kressner-Kiel D , Croy I
Published: June 2022

Study question

Do infertile couples differ from the average population in Human Leukocyte Antigen (HLA) similarity?

Summary answer

Infertile couples share a significantly higher number of genes than expected by chance in four out of six HLA loci.

What is known already

HLA genes encode the peptides for the formation of the innate immune system and are highly polymorphic. To allow increased variability of the innate immune system for the offspring, it is necessary that the parental alleles of the HLA complex are dissimilar. In animal studies, such mechanisms have been shown to play a role in mate choice. While some large studies show that humans in Western cultures do not engage in HLA-based mate choice, it has also long been hypothesized that a couple's fertility and pregnancy outcome is influenced by the degree of HLA similarity.

Study design, size, duration

A multicenter study including a total number of 609 couples was performed between May 2020 and November 2021 at a private fertility center and a department of reproductive medicine of a university clinic. All couples were diagnosed with primary infertility prior to assisted reproductive techniques. Buccal swab samples were provided by both partners to determine HLA profiles.

Participants/materials, setting, methods

Primary infertile couples (mean age women: 34.35 years, men: 37.59 years) were recruited before undergoing IVF or ICSI therapy. Couples with former pregnancies, tubal factor, azoospermia or donor therapies were excluded. Six different HLA genes (HLA-A, -B, -C, -DRB1, -DQB1 and -DPB1) were analysed using next-generation sequencing. Subsequently the number of HLA similarities was determined per couple. Comparison against chance level was performed using a random permutation approach with 100,000 repetitions.

Main results and the role of chance

Our analysis revealed a higher degree of HLA similarity in infertile couples, than expected by chance, for the loci HLA-C, -DPB1, -DRB1 and HLA-DQB1, but not for the loci HLA-A and HLA-B. A priori power analysis was performed to statistically ensure a small effect size at a �  = 0.05 ������������ 1 − �  = 0.95 and resulted in a number of 536 couples.

Limitations, reasons for caution

Conclusions are limited due to the inclusion of predominantly Caucasian couples.

Wider implications of the findings

This study adds new evidence to former publications with small study groups. HLA similarities may be a contributing factor to primary infertility. Further on, we will examine whether HLA similarities relate to success rates of infertility treatment and outcome of pregnancies.

Trial registration number

not applicable
P-740 Social disparities in pregnancy awareness among individuals in the general U.S. population
Authors: Zhang Y , Rosa G , Mustieles V , Sun Y , Bibi Z , Torres N , Hillcoat A , Wang Y.X , Messerlian C
Published: June 2022

Study question

What are socio-demographic and lifestyle characteristics of pregnant individuals who were aware versus those who were unaware of pregnancy status in the general U.S. population.

Summary answer

Women unaware of their pregnancy status were more likely to be Non-Hispanic Black, living below the poverty line, and unmarried.

What is known already

The early weeks of pregnancy are critical for fetal programming of organ systems and consequently long-term offspring health. Individuals who are unaware of pregnancy are at risk of poor nutrition, inadvertent environmental chemical exposures and risky behaviors/lifestyles that contribute to inadequate prenatal care. Lack of pregnancy awareness increases the risk of pregnancy complications and misses opportunities for early intervention.

Study design, size, duration

We included 842 individuals aged between 20 to 44 years who had a positive urine pregnancy test result at time of the cross-sectional National Health and Examination Survey (NHANES), 2003-2016 cycles.

Participants/materials, setting, methods

The urine pregnancy tests and reproductive health interviews were conducted concurrently in medical examination center. We defined participants with a positive urine pregnancy test result but who reported not being pregnant during the interview as being unaware of their pregnancy status. Information on demographic, socio-economic, and lifestyle characteristics were collected by questionnaires. We employed student t test and chi-square test to compare the characteristics between individuals who were aware vs. unaware of the pregnancy.

Main results and the role of chance

Among 842 pregnant individuals, 62 (7.36%) were unaware of their pregnancy status. The mean (SE) ages (years) were similar between individuals who were unaware vs. those aware of their pregnancy status (Unaware: 28.05 (0.96) vs. Aware: 28.48 (0.32)). Compared with aware individuals, a higher proportion of the unaware group were Non-Hispanic Black (Unaware: 36.31% vs. Aware: 13.06%; p < 0.001), living in poverty (Unaware: 30.03% vs. Aware: 18.95%; p = 0.09), and unmarried (Unaware: 68.12% vs. Aware: 30.45%; p < 0.001). No significant differences were found for education (College degree and above: Unaware: 60.73% vs. Aware: 67.73%; p = 0.33) and smoking behavior between the two groups (Current smoker: Unaware: 4.97% vs. Aware: 8.88%; p = 0.38).

Limitations, reasons for caution

The sample size of this study was relatively small. Findings may not be representative of population characteristics.

Wider implications of the findings

Our findings point to significant social disparities in pregnancy awareness and have important implications for clinical practice and early identification of high-risk pregnancies.

Trial registration number

not applicable
Sucker Shapes, Skeletons, and Bioinspiration: How Hard and Soft Tissue Morphology Generates Adhesive Performance in Waterfall Climbing Goby Fishes
Authors: Palecek A M , Schoenfuss H L , Blob R W
Published: June 2022

Synopsis

Many teleost fish, such as gobies, have fused their paired pelvic fins into an adhesive disc. Gobies can use their pelvic suckers to generate passive adhesive forces (as in engineered suction cups), and different species exhibit a range of adhesive performance, with some even able to climb waterfalls. Previous studies have documented that, in the Hawaiian Islands, species capable of climbing higher waterfalls produce the highest passive pull-off forces, and species found at higher elevation sites are likely to have more rounded suction discs than those found in the lowest stream segments. Morphology of the pelvic girdle also varies between species, with more robust skeletons in taxa with superior passive adhesion. To investigate what factors impact the passive adhesive performance of waterfall climbing gobies, we tested biomimetic suction cups designed with a range of shapes and embedded bioinspired “skeletons” based on micro-CT scans of goby pelvic girdles. We found that while the presence of an internal skeleton may provide some support against failure, the performance of suction cups may be more strongly affected by their external shape. Nonetheless, factors besides external shape and skeletal morphology may still have a stronger influence on sucker tenacity. Our results suggest that the relationship between suction disc morphology and adhesive performance may be influenced by a variety of physical factors, and live animal performance likely is further complicated by muscle activation and climbing behavior. These results have implications for the evolution of suction disc shape in adhesive fish and for improving the design of biomimetic suction cups.
The Comparative Approach to Bio-Inspired Design: Integrating Biodiversity and Biologists into the Design Process
Authors: Penick Clint A , Cope Grace , Morankar Swapnil , Mistry Yash , Grishin Alex , Chawla Nikhilesh , Bhate Dhruv
Published: June 2022

Biodiversity provides a massive library of ideas for bio-inspired design, but the sheer number of species to consider can be daunting. Current approaches for sifting through biodiversity to identify relevant biological models include searching for champion adapters that are particularly adept at solving a specific design challenge. While the champion adapter approach has benefits, it tends to focus on a narrow set of popular models while neglecting the majority of species. An alternative approach to bio-inspired design is the comparative method, which leverages biodiversity by drawing inspiration across a broad range of species. This approach uses methods in phylogenetics to map traits across evolutionary trees and compare trait variation to infer structure–function relationships. Although comparative methods have not been widely used in bio-inspired design, they have led to breakthroughs in studies on gecko-inspired adhesives and multifunctionality of butterfly wing scales. Here we outline how comparative methods can be used to complement existing approaches to bio-inspired design, and we provide an example focused on bio-inspired lattices, including honeycomb, and glass sponges. We demonstrate how comparative methods can lead to breakthroughs in bio-inspired applications as well as answer major questions in biology, which can strengthen collaborations with biologists and produce deeper insights into biological function.
The impact of electronic monitoring on fleet wide discarding of small cod in Scottish demersal fisheries
Authors: Holah Helen , Marshall C Tara , Needle Coby , Fryer Rob
Published: June 2022

In Europe, uptake of electronic monitoring (EM) has been hindered by a lack of potential cost savings, given low existing observer coverage, and resistance from industry to greater enforcement of the landing obligation. To assess why certain vessels volunteer for EM and what their subsequent changes in behaviour tell us about those of the wider fleet over time, this study investigates effects of EM on discarding of North Sea cod by Scottish demersal trawlers. As discard data were limited, weight of small cod (grade 5) landed per trip was selected as an indicator of discarding and modelled to describe discard patterns from 2006 to 2016 encompassing the EM-verified cod quota management scheme (2010–2016). Findings show that EM leads to reduced instances of discarding of small cod by participants. However, evidence suggests non-participant vessels were driven to greater levels of discarding due to quota acquisition by participants. Vessels volunteering for EM trials were not predisposed towards greater compliance. Landings data do not support the trial objective of incentivising avoidance of small cod being met. The influence of participants on non-participants has implications for how vessels are selected, and management of behavioural adaptions required to ensure participants remain representative of the wider fleet.
Adaptive tracking control for nonlinear system in pure-feedback form with prescribed performance and unknown hysteresis
Authors: Chang Yi , Niu Ben , Wang Huanqing , Zhang Liang , Ahmad Adil M , Alassafi Madini O
Published: June 2022

The finite-time tracking control issue for a class of nonlinear pure-feedback system with prescribed performance and unknown hysteresis is investigated in this work. To solve the Bouc-Wen hysteresis with unknown parameters and direction conditions, the Nussbaum function and auxiliary virtual control function are used. A finite-time performance function is applied in prescribed performance, which can make the tracking error is limited to a pre-given boundary in finite time. Moreover, the mean-value theorem is applied to solve the difficulty of pure-feedback form. Combined with backstepping technique, an adaptive tracking control scheme is designed to make sure that all the closed-loop signals are bounded and that the tracking error converges to pro-given boundary. Finally, a simulation example is presented to show the effectiveness of the proposed control scheme.