bluuebunny/crossref_metadata_2025 huggingface dataset:
Dehydration-induced earthquakes identified in a subducted oceanic slab beneath Vrancea, Romania
Authors: Ferrand Thomas P. , Manea Elena F.
Published: May 2021

Vrancea, Eastern Romania, presents a significant intermediate-depth seismicity, between 60 and 170 km depth, i.e. pressures from 2 to 6.5 GPa. A debate has been lasting for decades regarding the nature of the seismic volume, which could correspond to the remnant of a subducted slab of Tethyan lithosphere or a delamination of the Carpathians lithosphere. Here we compile the entire seismicity dataset (≈ 10,000 events with 2 ≤ Mw ≤ 7.9) beneath Vrancea for P > 0.55 GPa (> 20 km) since 1940 and estimate the pressure and temperature associated with each hypocenter. We infer the pressure and temperature, respectively, from a depth-pressure conversion and from the most recent tomography-based thermal model. Pressure–temperature diagrams show to what extent these hypocentral conditions match the thermodynamic stability limits for minerals typical of the uppermost mantle, oceanic crust and lower continental crust. The stability limits of lawsonite, chloritoid, serpentine and talc minerals show particularly good correlations. Overall, the destabilization of both mantle and crustal minerals could participate in explaining the observed seismicity, but mantle minerals appear more likely with more convincing correlations. Most hypocentral conditions match relatively well antigorite dehydration between 2 and 4.5 GPa; at higher pressures, the dehydration of the 10-Å phase provides the best fit. We demonstrate that the Vrancea intermediate-depth seismicity is evidence of the current dehydration of an oceanic slab beneath Romania. Our results are consistent with a recent rollback of a W-dipping oceanic slab, whose current location is explained by limited delamination of the continental Moesian lithosphere between the Tethyan suture zone and Vrancea.
Remarkable plasma-resistance performance by nanocrystalline Y2O3·MgO composite ceramics for semiconductor industry applications
Authors: Oh Hyeon-Myeong , Park Young-Jo , Kim Ha-Neul , Kumar Kundan , Ko Jae-Woong , Lee Chae-Eon , Lee Hyun-Kwuon
Published: May 2021

Motivated by recent finding of crystallographic-orientation-dependent etching behavior of sintered ceramics, the plasma resistance of nanocrystalline Y2O3-MgO composite ceramics (YM) was evaluated for the first time. We report a remarkably high plasma etching resistance of nanostructure YM surpassing the plasma resistance of commercially used transparent Y2O3 and MgAl2O4 ceramics. The pore-free YM ceramic with grain sizes of several hundred nm was fabricated by hot press sintering, enabling theoretical maximum densification at low temperature. The insoluble two components effectively suppressed the grain growth by mutual pinning. The engineering implication of the developed YM nanocomposite imparts enhanced mechanical reliability, better cost effectiveness with excellent plasma resistance property over their counterparts in plasma using semiconductor applications.
Transient fixation of L4 vertebra preserves lumbar motion and function in Lenke Type 5C and 6C scoliosis
Authors: Yang Jae-Ho , Shin Jae-Won , Park Sub-Ri , Kim Sun-Kyu , Park Sang-Jun , Min Ji-Hwan , Lee Byoung-Ho , Suk Kyung-Soo , Park Jin-Oh , Moon Seong-Hwan , Lee Hwan-Mo , Kim Hak-Sun
Published: May 2021

This study investigated the efficacy of a novel surgical method that relies on the transient fixation of L4 in Lenke Type 5C and 6C adolescent idiopathic scoliosis. Thirty-six transient surgically treated L4 fixation patients were retrospectively evaluated. The first surgery involved mechanical correction of scoliosis; the lowest instrumented vertebra (LIV) was L4. After an average of 1.3 years (range, 0.3–3.4), the second surgery to remove transient L4 pedicle screws was performed. Radiographic parameters and SRS-22 scores were measured. Cobb’s angle, coronal balance, LIV tilting angle, and LIV coronal disc angle clearly improved after the first surgery (p < 0.01). After the second surgery, the corrected Cobb angle (p = 0.446) and coronal balance were maintained (p = 0.271). Although L3/S1 lumbar lordosis decreased after the first surgery (p < 0.01), after removal of transient L4 pedicle screws, it recovered slightly (p = 0.03). Similarly, the preoperative L3/4 lateral disc mobility eventually recovered after transient L4 screw removal (p < 0.01). The function domain of the SRS-22 showed better scores after removal of transient L4 screws (p = 0.04). L4 transient fixation surgery is beneficial for Lenke Type 5C and 6C scolioses that do not fully satisfy LIV (L3) criteria. It preserves L3/4 disc motion, increases functional outcomes, and maintains spinal correction and coronal balance.
Admission C-reactive protein concentrations are associated with unfavourable neurological outcome after out-of-hospital cardiac arrest
Authors: Schriefl Christoph , Schoergenhofer Christian , Poppe Michael , Clodi Christian , Mueller Matthias , Ettl Florian , Jilma Bernd , Grafeneder Juergen , Schwameis Michael , Losert Heidrun , Holzer Michael , Sterz Fritz , Zeiner-Schatzl Andrea
Published: May 2021

Whether admission C-reactive protein (aCRP) concentrations are associated with neurological outcome after out-of-hospital cardiac arrest (OHCA) is controversial. Based on established kinetics of CRP, we hypothesized that aCRP may reflect the pre-arrest state of health and investigated associations with neurological outcome. Prospectively collected data from the Vienna Clinical Cardiac Arrest Registry of the Department of Emergency Medicine were analysed. Adults (≥ 18 years) who suffered a non-traumatic OHCA between January 2013 and December 2018 with return of spontaneous circulation, but without extracorporeal cardiopulmonary resuscitation therapy were eligible. The primary endpoint was a composite of unfavourable neurologic function or death (defined as Cerebral Performance Category 3–5) at 30 days. Associations of CRP levels drawn within 30 min of hospital admission were assessed using binary logistic regression. ACRP concentrations were overall low in our population (n = 832), but higher in the unfavourable outcome group [median: 0.44 (quartiles 0.15–1.44) mg/dL vs. 0.26 (0.11–0.62) mg/dL, p < 0.001]. The crude odds ratio for higher aCRP concentrations was 1.19 (95% CI 1.10–1.28, p < 0.001, per mg/dL) to have unfavourable neurological outcome. After multivariate adjustment for traditional prognostication markers the odds ratio of higher aCRP concentrations was 1.13 (95% CI 1.04–1.22, p = 0.002). Sensitivity of aCRP was low, but specificity for unfavourable neurological outcome was 90% for the cut-off at 1.5 mg/dL and 97.5% for 5 mg/dL CRP. In conclusion, high aCRP levels are associated with unfavourable neurological outcome at day 30 after OHCA.
Impact of aging on gene expression response to x-ray irradiation using mouse blood
Authors: Broustas Constantinos G. , Duval Axel J. , Amundson Sally A.
Published: May 2021

As a radiation biodosimetry tool, gene expression profiling is being developed using mouse and human peripheral blood models. The impact of dose, dose-rate, and radiation quality has been studied with the goal of predicting radiological tissue injury. In this study, we determined the impact of aging on the gene expression profile of blood from mice exposed to radiation. Young (2 mo) and old (21 mo) male mice were irradiated with 4 Gy x-rays, total RNA was isolated from whole blood 24 h later, and subjected to whole genome microarray analysis. Pathway analysis of differentially expressed genes revealed young mice responded to x-ray exposure by significantly upregulating pathways involved in apoptosis and phagocytosis, a process that eliminates apoptotic cells and preserves tissue homeostasis. In contrast, the functional annotation of senescence was overrepresented among differentially expressed genes from irradiated old mice without enrichment of phagocytosis pathways. Pathways associated with hematologic malignancies were enriched in irradiated old mice compared with irradiated young mice. The fibroblast growth factor signaling pathway was underrepresented in older mice under basal conditions. Similarly, brain-related functions were underrepresented in unirradiated old mice. Thus, age-dependent gene expression differences should be considered when developing gene signatures for use in radiation biodosimetry.
Low ventilatory responsiveness to transient hypoxia or breath-holding predicts fast marathon performance in healthy middle-aged and older men
Authors: Paleczny Bartłomiej , Seredyński Rafał , Wyciszkiewicz Małgorzata , Nowicka-Czudak Adrianna , Łopusiewicz Wojciech , Adamiec Dorota , Wiecha Szczepan , Mroczek Dariusz , Chmura Paweł , Konefał Marek , Maćkała Krzysztof , Chromik Krystyna , Pawlik Damian , Andrzejewski Marcin , Chmura Jan , Ponikowski Piotr , Ponikowska Beata
Published: May 2021

The aim of this study was to test the utility of haemodynamic and autonomic variables (e.g. peripheral chemoreflex sensitivity [PCheS], blood pressure variability [BPV]) for the prediction of individual performance (marathon time and VO2max) in older men. The post-competition vasodilation and sympathetic vasomotor tone predict the marathon performance in younger men, but their prognostic relevance in older men remains unknown. The peripheral chemoreflex restrains exercise-induced vasodilation via sympathetically-mediated mechanism, what makes it a plausible candidate for the individual performance marker. 23 men aged ≥ 50 year competing in the Wroclaw Marathon underwent an evaluation of: resting haemodynamic parameters, PCheS with two methods: transient hypoxia and breath-holding test (BHT), cardiac barosensitivity, heart rate variability (HRV) and BPV, plasma renin and aldosterone, VO2max in a cardiopulmonary exercise test (CPET). All tests were conducted twice: before and after the race, except for transient hypoxia and CPET which were performed once, before the race. Fast marathon performance and high VO2max were correlated with: low ventilatory responsiveness to hypoxia (r =  − 0.53, r = 0.67, respectively) and pre-race BHT (r =  − 0.47, r = 0.51, respectively), (1) greater SD of beat-to-beat SBP (all p < 0.05). Fast performance was related with an enhanced pre-race vascular response to BHT (r =  − 0.59, p = 0.005). The variables found by other studies to predict the marathon performance in younger men: post-competition vasodilation, sympathetic vasomotor tone (LF-BPV) and HRV were not associated with the individual performance in our population. The results suggest that PCheS (ventilatory response) predicts individual performance (marathon time and VO2max) in men aged ≥ 50 yeat. Although cause-effect relationship including the role of peripheral chemoreceptors in restraining the post-competition vasodilation via the sympathetic vasoconstrictor outflow may be hypothesized to underline these findings, the lack of correlation between individual performance and both, the post-competition vasodilation and the sympathetic vasomotor tone argues against such explanation. Vascular responsiveness to breath-holding appears to be of certain value for predicting individual performance in this population, however.
Compressive spectral image fusion via a single aperture high throughput imaging system
Authors: Rueda-Chacon Hoover , Rojas Fernando , Arguello Henry
Published: May 2021

Spectral image fusion techniques combine the detailed spatial information of a multispectral (MS) image and the rich spectral information of a hyperspectral (HS) image into a high-spatial and high-spectral resolution image. Due to the data deluge entailed by such images, new imaging modalities have exploited their intrinsic correlations in such a way that, a computational algorithm can fuse them from few multiplexed linear projections. The latter has been coined compressive spectral image fusion. State-of-the-art research work have focused mainly on the algorithmic part, simulating instrumentation characteristics and assuming independently registered sensors to conduct compressed MS and HS imaging. In this manuscript, we report on the construction of a unified computational imaging framework that includes a proof-of-concept optical testbed to simultaneously acquire MS and HS compressed projections, and an alternating direction method of multipliers algorithm to reconstruct high-spatial and high-spectral resolution images from the fused compressed measurements. The testbed employs a digital micro-mirror device (DMD) to encode and split the input light towards two compressive imaging arms, which collect MS and HS measurements, respectively. This strategy entails full light throughput sensing since no light is thrown away by the coding process. Further, different resolutions can be dynamically tested by binning the DMD and sensors pixels. Real spectral responses and optical characteristics of the employed equipment are obtained through a per-pixel point spread function calibration approach to enable accurate compressed image fusion performance. The proposed framework is demonstrated through real experiments within the visible spectral range using as few as 5% of the data.
Regulation of mammalian 3D genome organization and histone H3K9 dimethylation by H3K9 methyltransferases
Authors: Fukuda Kei , Shimura Chikako , Miura Hisashi , Tanigawa Akie , Suzuki Takehiro , Dohmae Naoshi , Hiratani Ichiro , Shinkai Yoichi
Published: May 2021

Histone H3 lysine 9 dimethylation (H3K9me2) is a highly conserved silencing epigenetic mark. Chromatin marked with H3K9me2 forms large domains in mammalian cells and overlaps well with lamina-associated domains and the B compartment defined by Hi-C. However, the role of H3K9me2 in 3-dimensional (3D) genome organization remains unclear. Here, we investigated genome-wide H3K9me2 distribution, transcriptome, and 3D genome organization in mouse embryonic stem cells following the inhibition or depletion of H3K9 methyltransferases (MTases): G9a, GLP, SETDB1, SUV39H1, and SUV39H2. We show that H3K9me2 is regulated by all five MTases; however, H3K9me2 and transcription in the A and B compartments are regulated by different MTases. H3K9me2 in the A compartments is primarily regulated by G9a/GLP and SETDB1, while H3K9me2 in the B compartments is regulated by all five MTases. Furthermore, decreased H3K9me2 correlates with changes to more active compartmental state that accompanied transcriptional activation. Thus, H3K9me2 contributes to inactive compartment setting.
Reduced resilience of terrestrial ecosystems locally is not reflected on a global scale
Authors: Feng Yuhao , Su Haojie , Tang Zhiyao , Wang Shaopeng , Zhao Xia , Zhang Heng , Ji Chengjun , Zhu Jiangling , Xie Ping , Fang Jingyun
Published: May 2021

Global climate change likely alters the structure and function of vegetation and the stability of terrestrial ecosystems. It is therefore important to assess the factors controlling ecosystem resilience from local to global scales. Here we assess terrestrial vegetation resilience over the past 35 years using early warning indicators calculated from normalized difference vegetation index data. On a local scale we find that climate change reduced the resilience of ecosystems in 64.5% of the global terrestrial vegetated area. Temperature had a greater influence on vegetation resilience than precipitation, while climate mean state had a greater influence than climate variability. However, there is no evidence for decreased ecological resilience on larger scales. Instead, climate warming increased spatial asynchrony of vegetation which buffered the global-scale impacts on resilience. We suggest that the response of terrestrial ecosystem resilience to global climate change is scale-dependent and influenced by spatial asynchrony on the global scale.
Emerging investigator series: aramid amphiphile nanoribbons for the remediation of lead from contaminated water
Authors: Christoff-Tempesta Ty , Ortony Julia H.
Published: May 2021

Aramid amphiphiles with chelating head groups spontaneously form robust nanoribbons in water with surfaces capable of heavy metal remediation.
Monitoring and quantitative evaluation of Faraday cup deterioration in a thermal ionization mass spectrometer using multidynamic analyses of laboratory standards
Authors: Di Yankun , Li Zefeng , Amelin Yuri
Published: May 2021

We develop a method to quantitatively monitor Faraday cup deterioration using multidynamic analyses of standards. The deposition of measured elements in cups can effectively alter Faraday cup efficiencies, but the response function is complex.
A highly transparent ionogel with strength enhancement ability for robust bonding in an aquatic environment
Authors: Yu Zhenchuan , Wu Peiyi
Published: May 2021

An ionogel with strength enhancement ability was developed for underwater adhesion. Taking advantage of the excellent interface adaptability and high mechanical strength of the ionogel, its underwater adhesion strength can reach 5.18 ± 0.27 MPa.
Correction: High performance blue quantum dot light-emitting diodes by attaching diffraction wrinkle patterns
Authors: Qi Hui , Wang Shujie , Li Chenguang , Zhao Yaolong , Xu Bo , Jiang Xiaohong , Fang Yan , Wang Aqiang , Shen Huaibin , Du Zuliang
Published: May 2021

Correction for ‘High performance blue quantum light-emitting diodes by attaching diffraction wrinkle patterns’ by Hui Qi et al., Nanoscale, 2021, DOI: 10.1039/D1NR00082A.
The fluorination-assisted dealloying synthesis of porous reduced graphene oxide-FeF2@carbon for high-performance lithium-ion battery and the exploration of its electrochemical mechanism
Authors: Li Jianming , Meng Yan , Wang Yujue , Li Xiaopeng , Lai Yingling , Guo Yong , Wen Xiaogang , Xiao Dan
Published: May 2021

Based on the dealloying conception, a porous rGO-FeF2@C is attained and shows a great electrochemical performance. An intriguing phenomenon has been that the decrease in charge cut-off voltage contributes to the higher discharge plateau.
Remote C(sp3)–H functionalizationviacatalytic cyclometallation: beyond five-membered ring metallacycle intermediates
Authors: Mingo Mario Martínez , Rodríguez Nuria , Arrayás Ramón Gómez , Carretero Juan C.
Published: May 2021

Despite impressive recent momentum gained in C(sp3)–H activation, achieving high regioselectivity in molecules containing different C–H bonds with similar high energy without abusing tailored substitution remains as one of the biggest challenges.
Regioselective synthesis of indenones via nickel-catalyzed Larock annulations
Authors: Liu Feipeng , Li Yongjie , Wang Xuchao , Qiang Qing , Yan Zijuan , Zhang Yao , Rong Zi-Qiang
Published: May 2021

A highly effective approach for the synthesis of indenones via nickel-catalyzed Larock annulations of substituted 2-formylphenyl trifluoromethanesulfonate with alkynes has been developed.
Correction: Integrated all-solid-state sulfite sensors modified with two different ion-to-electron transducers: rapid assessment of sulfite in beverages
Authors: Abd-Rabboh Hisham S. M. , El-Galil E. Amr Abd , Kamel Ayman H. , Al-Omar Mohamed A. , Sayed Ahmed Y. A.
Published: May 2021

Correction for ‘Integrated all-solid-state sulfite sensors modified with two different ion-to-electron transducers: rapid assessment of sulfite in beverages’ by Hisham S. M. Abd-Rabboh et al., RSC Adv., 2021, 11, 3783–3791, DOI: 10.1039/D0RA09903A.
Unklare Lymphadenopathie mit Panzytopenie bei einer Patientin mit rezidivierenden Hypoglykämien
Authors: Lindmeyer Anna M. , Nauck Michael A. , Meier Juris J.
Published: May 2021

Eine Patientin wurde aufgrund rezidivierender postprandialer Hypoglykämien nach Roux-en-Y-Magenbypass mit Diazoxid behandelt, nachdem eine Ernährungsumstellung keine Symptomlinderung erzielt hatte. Nach Eindosierung von Diazoxid mit guter Akutverträglichkeit wurde die Patientin entlassen. Eine Woche nach Therapieeinleitung kam es zu einer Lymphadenopathie und Panzytopenie. Es fanden sich keine Hinweise auf das Vorliegen eines Infekts. Nach Absetzen von Diazoxid sistierten die Beschwerden. Unser Fallbericht weist auf seltene unerwünschte hämatologische Arzneimittelwirkungen unter Diazoxid hin.
Using a Simple Prescription Gap to Determine Warfarin Discontinuation Can Lead to Substantial Misclassification
Authors: Lin Kueiyu Joshua , Schneeweiss Sebastian , Pawar Ajinkya , Singer Daniel E. , Liu Jun , Gagne Joshua J.
Published: May 2021

Background Warfarin remains widely used and a key comparator in studies of other direct oral anticoagulants. As longer-than-needed warfarin prescriptions are often provided to allow for dosing adjustments according to international normalized ratios (INRs), the common practice of using a short allowable gap between dispensings to define warfarin discontinuation may lead to substantial misclassification of warfarin exposure. We aimed to quantify such misclassification and determine the optimal algorithm to define warfarin discontinuation.

Methods We linked Medicare claims data from 2007 to 2014 with a multicenter electronic health records system. The study cohort comprised patients ≥65 years with atrial fibrillation and venous thromboembolism initiating warfarin. We compared results when defining warfarin discontinuation by (1) different gaps (3, 7, 14, 30, and 60 days) between dispensings and (2) having a gap ≤60 days or bridging larger gaps if there was INR ordering at least every 42 days (60_INR). Discontinuation was considered misclassified if there was an INR ≥2 within 7 days after the discontinuation date.

Results Among 3,229 patients, a shorter gap resulted in a shorter mean follow-up time (82, 95, 117, 159, 196, and 259 days for gaps of 3, 7, 14, 30, 60, and 60_INR, respectively; p < 0.001). Incorporating INR (60_INR) can reduce misclassification of warfarin discontinuation from 68 to 4% (p < 0.001). The on-treatment risk estimation of clinical endpoints varied significantly by discontinuation definitions.

Conclusion Using a short gap between warfarin dispensings to define discontinuation may lead to substantial misclassification, which can be improved by incorporating intervening INR codes.
Optimal Tests to Minimise Bleeding and Ischaemic Complications in Patients on Extracorporeal Membrane Oxygenation
Authors: Kanji Rahim , Vandenbriele Christophe , Arachchillage Deepa R. J. , Price Susanna , Gorog Diana Adrienne
Published: May 2021

Patients supported with extracorporeal membrane oxygenation (ECMO) experience a very high frequency of bleeding and ischaemic complications, including stroke and systemic embolism. These patients require systemic anticoagulation, mainly with unfractionated heparin (UFH) to prevent clotting of the circuit and reduce the risk of arterial or venous thrombosis. Monitoring of UFH can be very challenging. While most centres routinely monitor the activated clotting time and activated partial thromboplastin time (aPTT) to assess UFH, measurement of anti-factor Xa (anti-Xa) level best correlates with heparin dose, and appears to be predictive of circuit thrombosis, although aPTT may be a better predictor of bleeding. Although monitoring of prothrombin time, platelet count and fibrinogen is routinely undertaken to assess haemostasis, there is no clear guidance available regarding the optimal test.

Additional tests, including antithrombin level and thromboelastography, can be used for risk stratification of patients to try and predict the risks of thrombosis and bleeding. Each has their specific role, strengths and limitations. Increased thrombin generation may have a role in predicting thrombosis. Acquired von Willebrand syndrome is frequent with ECMO, contributing to bleeding risk and can be detected by assessing the von Willebrand factor activity-to-antigen ratio, while the platelet function analyser can be used in urgent situations to detect this, with a high negative predictive value. Tests of platelet aggregation can aid in the prediction of bleeding.

To personalise management, a selection of complementary tests to collectively assess heparin-effect, coagulation, platelet function and platelet aggregation is proposed, to optimise clinical outcomes in these high-risk patients.
A Step-by-step Sonographic Approach to Vascular Anomalies in the Pediatric Population: A Pictorial Essay
Authors: Mittal Anushka , Anand Rama , Gauba Richa , Choudhury Subhasis Roy , Abbey Pooja
Published: May 2021

Vascular anomalies are a common cause of soft-tissue masses in children and often referred for ultrasonographic (USG) evaluation. They are broadly classified as vascular tumors (hemangiomas, hemangioendotheliomas, and angiosarcomas) or vascular malformations (venous malformations, lymphatic malformations, and arteriovenous malformations). Findings on USG and Doppler imaging can be used to categorize vascular anomalies into high- or low-flow lesions, which forms the basis for further workup, diagnosis, and management. On careful evaluation of various sonographic features, in conjunction with clinical findings, an accurate clinicoradiological diagnosis can be made in most cases. Further imaging with magnetic resonance (MR) imaging or computed tomography (CT) helps in delineation of lesion extent, whereas MR or CT angiography is useful to map the vascular supply of high-flow lesions. We have illustrated and discussed a step-by-step approach to diagnose vascular anomalies using ultrasound and Doppler imaging.
Dynamics of coupled modified Rössler oscillators: The role of nonisochronicity parameter
Authors: Ramya C. , Gopal R. , Suresh R. , Chandrasekar V. K.
Published: May 2021

The amplitude-dependent frequency of the oscillations, termed nonisochronicity, is one of the essential characteristics of nonlinear oscillators. In this paper, the dynamics of the Rössler oscillator in the presence of nonisochronicity is examined. In particular, we explore the appearance of a new fixed point and the emergence of a coexisting limit-cycle and quasiperiodic attractors. We also describe the sequence of bifurcations leading to synchronized, desynchronized attractors and oscillation death states in the coupled Rössler oscillators as a function of the strength of nonisochronicity and coupling parameters. Furthermore, we characterize the multistability of the coexisting attractors by plotting the basins of attraction. Our results open up the possibilities of understanding the emergence of coexisting attractors and into a qualitative change of the collective states in coupled nonlinear oscillators in the presence of nonisochronicity.
Skyrmion logic clocked via voltage-controlled magnetic anisotropy
Authors: Walker Benjamin W. , Cui Can , Garcia-Sanchez Felipe , Incorvia Jean Anne C. , Hu Xuan , Friedman Joseph S.
Published: May 2021

Magnetic skyrmions are exciting candidates for energy-efficient computing due to their nonvolatility, detectability, and mobility. A recent proposal within the paradigm of reversible computing enables large-scale circuits composed of directly cascaded skyrmion logic gates, but it is limited by the manufacturing difficulty and energy costs associated with the use of notches for skyrmion synchronization. To overcome these challenges, we, therefore, propose a skyrmion logic synchronized via modulation of voltage-controlled magnetic anisotropy (VCMA). In addition to demonstrating the principle of VCMA synchronization through micromagnetic simulations, we also quantify the impacts of current density, skyrmion velocity, and anisotropy barrier height on skyrmion motion. Further micromagnetic results demonstrate the feasibility of cascaded logic circuits in which VCMA synchronizers enable clocking and pipelining, illustrating a feasible pathway toward energy-efficient large-scale computing systems based on magnetic skyrmions.
Central moment lattice Boltzmann method on a rectangular lattice
Authors: Yahia Eman , Premnath Kannan N.
Published: May 2021

Simulating inhomogeneous flows with different characteristic scales in different coordinate directions using the collide-and-stream based lattice Boltzmann methods (LBMs) can be accomplished efficiently using rectangular lattice grids. We develop and investigate a new rectangular central moment LBM based on a non-orthogonal moment basis and involving multiple relaxation times. The equilibria to which the central moments relax under collision in this approach are obtained from matching with those corresponding to the continuous Maxwell distribution. A Chapman–Enskog analysis is performed to derive the correction terms to the second order moment equilibria involving the grid aspect ratio and velocity gradients that restore the isotropy of the viscous stress tensor and eliminate the non-Galilean invariant cubic velocity terms in the resulting hydrodynamical equations. A special case of this rectangular formulation involving the raw moments is also constructed. The resulting schemes represent a considerable simplification, especially for the transformation matrices and isotropy corrections, and improvement over the existing lattice Boltzmann schemes based on raw moments on rectangular lattice grids that use orthogonal moment basis. Numerical validation study of both the proposed rectangular LBMs for a variety of benchmark flows is performed, which shows good accuracy at various grid aspect ratios. The ability of our proposed schemes to simulate flows at relatively low grid aspect ratios and higher Reynolds numbers than considered in prior approaches is demonstrated. Furthermore, simulations reveal the superior stability characteristics of the rectangular central moment LBM over that based on raw moments in handling shear flows at lower viscosities and/or higher characteristic velocities. In addition, computational advantages of using our rectangular LB formulation in lieu of that based on the square lattice are shown.
Design and operation of a portable micro-photoluminescence spectrometer for education on semiconductor quantum structures and graphene sheets
Authors: Heyn Christian
Published: May 2021

The design and operation of a portable micro-photoluminescence spectrometer for applications in education is described. Guidelines are a compact, robust, portable, and flexible design; operation without cryogenic media for sample cooling; and a limited budget. Targeted samples are semiconductor quantum structures emitting in a wavelength range of 600–1000 nm and graphene sheets. The portable spectrometer includes a reflected-light microscope with a motorized sample stage of 156 nm step size, a thermoelectric sample cooler allowing temperatures down to 196 K, a green and a blue laser for focused excitation, a monochromator with 0.18 nm spectral resolution, and a cooled camera as the image sensor. For demonstration of the capabilities of the spectrometer, measurements of the quantized energy levels of molecular beam epitaxy grown GaAs quantum dots (QDs) are shown. Here, different sample designs are used, the sample temperature as well as the laser excitation power and energy is varied, and the respective influence on the measurements is discussed. A clear QD shell structure with four states is shown for a sample, where approximately four QDs are directly excited by a focused laser. Limitations of the spectrometer for QD characterization mainly due to the waiver of cryogenic media for sample cooling are discussed. As a further example, which does not require sample cooling, local Raman spectroscopy of a graphene sheet is demonstrated where clear Raman signatures allow the identification of a single-layer thickness.
Study of charge density waves in suspended 2H-TaS2 and 2H-TaSe2 by nanomechanical resonance
Authors: Lee Martin , Šiškins Makars , Mañas-Valero Samuel , Coronado Eugenio , Steeneken Peter G. , van der Zant Herre S. J.
Published: May 2021

The charge density wave (CDW) state in van der Waals systems shows interesting scaling phenomena as the number of layers can significantly affect the CDW transition temperature, TCDW. However, it is often difficult to use conventional methods to study the phase transition in these systems due to their small size and sensitivity to degradation. Degradation is an important parameter, which has been shown to greatly influence the superconductivity in layered systems. Since the CDW state competes with the onset of superconductivity, it is expected that TCDW will also be affected by the degradation. Here, we probe the CDW phase transition by the mechanical resonances of suspended 2H-TaS2 and 2H-TaSe2 membranes and study the effect of disorder on the CDW state. Pristine flakes show the transition near the reported values of 75 K and 122 K, respectively. We then study the effect of degradation on 2H-TaS2, which displays an enhancement of TCDW up to 129 K after degradation in ambient air. Finally, we study a sample with local degradation and observe that multiple phase transitions occur at 87 K, 103 K, and 118 K with a hysteresis in temperature in the same membrane. The observed spatial variations in the Raman spectra suggest that variations in crystal structure cause domains with different transition temperatures, which could result in the hysteresis. This work shows the potential of using nanomechanical resonance to characterize the CDW in suspended 2D materials and demonstrates that the degradation can have a large effect on transition temperatures.
Estimating flying-fox mortality associated with abandonments of pups and extreme heat events during the austral summer of 2019–20
Authors: Mo Matthew , Roache Mike , Davies Janine , Hopper Judith , Pitty Hugh , Foster Natalie , Guy Sandra , Parry-Jones Kerryn , Francis Geoff , Koosmen Audrey , Colefax Leah , Costello Chelsea , Stokes Josie , Curran Sarah , Smith Michael , Daly Garry , Simmons Carla-Maree , Hansen Rhonda , Prophet Desley , Judge Sara , Major Fiona , Hogarth Tamsyn , McGarry Carole-Ann , Pope Lawrence , Brend Stephen , Coxon Drew , Baker Kimberly , Kaye Kylie , Collins Linda , Wallis Michelle , Brown Rachel , Roberts Lisa , Taylor Susan , Pearson Tim , Bishop Tania , Dunne Pauline , Coutts-McClelland Kylie , Oliver Lorraine , Dawe Chris , Welbergen Justin A.
Published: May 2021

Mass mortalities in flying-foxes occur in summers that reach extremely hot temperatures. In this study, we examine the spatiotemporal distributions of mortality from pup abandonments and extreme heat events in Australian flying-fox camps during the 2019–20 summer. We recorded data on flying-fox mortality in known affected camps and applied a standard method to estimate the number of deaths. Pup mortalities from abandonments were recorded in 10 camps in New South Wales. A minimum estimate of 2612 flying-foxes died in pup abandonments, the majority of which occurred in one camp in Bomaderry. Die-offs from extreme heat events were recorded in 40 camps associated with eight separate heat events in south-eastern Australia. A minimum estimate of 72 175 flying-foxes died during these heat events, which all occurred within the range of the threatened grey-headed flying-fox (Pteropus poliocephalus). Further, 409 and 2251 live flying-foxes were taken into care from pup abandonments and heat events respectively. The minimum mortality estimated represents the highest recorded mortality of Australian flying-foxes within a single summer. This highlights a need to restore vegetation in flying-fox foraging areas and camps, address anthropogenic climate change and gather more empirical data to inform heat stress interventions to minimise flying-fox mortalities.
Employing fluorescence analysis for real-time determination of the volume displacement of a pneumatically driven diaphragm micropump
Authors: Bott Hannah , Leonhardt Ronny , Laermer Franz , Hoffmann Jochen
Published: May 2021

In this work, we propose a new optical measurement method and setup to investigate the dynamic behavior of a pneumatically driven diaphragm micropump in a microfluidic system. The presented method allows a contact-free spatially and temporally resolved determination of the membrane displacement. Hence, it enables to derive the volume flow rate, generated by the micropump. The method is based on the Lambert–Beer law, which describes the intensity weakening of light traveling through a medium with an absorbing substance. The fluorescence emission of a medium can thus be related to the light traveling length. The measurement method is used to deduce the flow rate profile generated by the micropump of the Lab-on-Chip system Vivalytic from Bosch Healthcare Solutions. We further quantify effects of fluidic components and system parameters on the transient flow rates. This allows the determination of maximum flow rates and pumping cycle durations as a basis for the implementation of fluidic processes on the system. The presented method requires neither additional, integrated sensor components nor a complex measurement setup. It can be implemented in any microfluidic system with membrane-based, optically accessible micropumps without major hardware modifications.
Bistability of zigzag edge magnetism in graphene nanoribbons induced by electric field
Authors: Luo Ma
Published: May 2021

In the presence of the Hubbard interaction, graphene zigzag nanoribbons have spontaneous edge magnetism with anti-parallel configuration, whose amplitude can be tuned by a transversal electric field. As the electric field increases or decreases across a critical value, the edges are demagnetized or re-magnetized, respectively. A magnetic field at each edge determines the orientation of the re-magnetization. Thus, a combination of a slowly varying transversal electric field and magnetic field in monolayer graphene zigzag nanoribbons can drive the quantum system into a bistability loop. The same phenomenon can be induced in a bilayer/monolayer zigzag nanoribbon without the magnetic field, because the non-symmetry superexchange interaction controls the orientation of the re-magnetization. In this way, the quantum system is switched between ground state and quasi-stable excited state with different magnetism, band structures and conductance. This feature could be used to develop graphene-based spintronic nano-devices without magnetic field.
A mild molecular fusion route for the synthesis of polyhedral carbon nano-onions with high graphitization
Authors: Xie Siyu , Wang Jingyun , He Yongkai , Yan Hao , Wang Yu , Li Yage , Wang Sheng , Sun Xiaodan , Yao Youwei , Cai Qiang
Published: May 2021

Polyhedral carbon nano-onions (CNOs) compared with traditional quasi-spherical CNOs are more stable and have less defects, which will greatly broaden their potential applications. However, there still lacks of a suitable synthetic method. Here, we developed a simple molecular fusion route and templet growth method by which polyhedral CNOs can be successfully synthesized. Characterization of the polyhedral CNOs by transmission electron microscopy, x-ray diffraction and Raman spectroscopy indicates that they have an ultra-high degree of graphitization and a large cavity diameter of about 10 nm, which results in their low density of 1.42 g cm−3. In addition, the deeper reaction mechanism of polyhedral CNOs growth was also elucidated. It was found that the channel structure and the absorption of the templet play the crucial role during the formation of polyhedral CNOs.
Cr cation-anchored carbon nanosheets: synthesis, paramagnetism and ferromagnetism
Authors: Xia Baorui , Zhang Haiyi , Liao Zhongxin , Wu Jian-Feng , Hu Yongfeng , Shakouri Mohsen , Gao Daqiang , Xue Desheng
Published: May 2021

Since the successfully synthesis of monolayer graphene, carbon-based materials have attracted wide and extensive attentions from researches. Due to the excellent transport capacity and conductivity, they are promising to be applied in electronic devices, even substituting the silicon-based electronic devices, optoelectronics and spintronics. Nevertheless, due to the non magnetic feature, many efforts have been devoted to endow carbon materials magnetism to apply them in the spintronic devices fabrication. Herein, a strategy of Cr cation solely anchored on two-dimensional carbon nanosheets by Cr–N bonds is developed, which introduces magnetism in carbon nanosheets. By extended x-ray absorption fine structure characterization, Cr cations are demonstrated to be atomically dispersed with Cr–N3 coordination. And after Cr–N3 anchored, carbon nanosheets exhibit ferromagnetic features with paramagnetic background. The magnetization varies with Cr content and reaches the maximum (Cr: 2.0%, 0.86 emu g−1) under 3 T at 50 K. The x-ray magnetic circular dichroism and first-principle calculations indicate that the magnetism is caused by the Cr3+ component of the anchored Cr cations. This study sets a single cation anchoring carbon as a suitable candidate for future spintronics.
Analytic properties of the complete formal normal form for the Bogdanov–Takens singularity
*
Authors: Stróżyna Ewa , Żołądek Henryk
Published: May 2021

In Stróżyna E and Żołądek H (2015 Moscow Math. J.
15 141) a complete formal normal forms for germs of two-dimensional holomorphic vector fields with nilpotent singularity was obtained. That classification is quite nontrivial (7 cases), but it can be divided into general types like in the case of the elementary singularities. One could expect that also the analytic properties of the normal forms for the nilpotent singularities are analogous to the case of the elementary singularities. This is really true. In the cases analogous to the focus and the node the normal form is analytic. In the case analogous to the nonresonant saddle the normal form is often nonanalytic due to the small divisors phenomenon. In the cases analogous to the resonant saddles (including saddle-nodes) the normal form is nonanalytic due to bad properties of some homological operators associated with the first nontrivial term in the orbital normal form.
Multipartite entanglement purification using time-bin entanglement
Authors: Luo Cheng-Chen , Zhou Lan , Zhong Wei , Sheng Yu-Bo
Published: May 2021

Multipartite entanglement has been widely employed in quantum information processing. However, the unavoidable noise in quantum channels causes the maximally multipartite entangled state to degrade to the mixed state. In this paper, we propose a highly efficient multipartite entanglement purification protocol (MEPP) for the polarization Greenberger–Horne–Zeilinger state. Unlike conventional MEPPs, where two pairs of polluted entanglement are usually required, our protocol only requires one noisy copy of polarization-time-bin hyperentanglement and exploits the time-bin entanglement to purify the polarization entanglement. This feature increases the efficiency of our MEPP. Our MEPP may have potential applications in long-distance quantum communication.
Effect of the anionic center hydration on the activation barrier of intramolecular nucleophilic addition in αβ-unsaturated oximes
Authors: Pradedova A G , Kobychev V B
Published: May 2021

The mechanism of intramolecular nucleophilic addition in αβ-unsaturated oximes, as well as the effect of the anionic center hydration with one and two water molecules on the activation barriers of intramolecular cyclization, was studied using the B2PLYP-D2/6-311+G**//B3LYP(D)/6-31+G* method with the solvation effects included within the SMD model. The activation barrier for nucleophilic addition of the anionic center of the oxime group to the carbon skeleton of 3-ethyl-N-hydroxy-5-phenylpenten-3-imine-2 is about 21 kcal/mol. During the hydration of the anionic center with one water molecule, a strong complex is formed, which increases the activation barrier by ∼ 6 kcal / mol. The addition of a second water molecule leads to an even higher activation barrier (ΔG‡ = 28 kcal/mol), but promotes the binding of the leaving hydroxide ion.
Nanoscale Ni as a catalyst in MgH2 for hydrogen storage material
Authors: Rahwanto A , Ismail I , Nurmalita N , Mustanir  , Jalil Z
Published: May 2021

Supplying hydrogen to industrial users is now a major business around the world. One of the problems, before hydrogen can be implemented into today’s infrastructure is storing the hydrogen. In this report, we introduced a high-pressure milling method for preparing the MgH2 catalyzed with Ni nanoparticle. We have reactively milled the MgH2 + 2 mol % Ni, which has size ∼90 nm, under 100 bar of hydrogen. The structural changes during milling were characterized by XRD and high-resolution scanning electron microscopy. The hydrogen sorption properties were studied by gravimetric analysis. As the results, it was showed that the milling process reduced into 2 h. The sorption kinetics was proceeding 5.3 wt% of hydrogen around 5 min at 300°C, while desorption in 50 mbar was completed within 4 min. Preparing the Mg-based hydrides under high pressure with 2 mol% Ni in nanoscale as catalyst improved the hydrogen storage properties and decreased the milling time, as well.
Synthesis and characterization of nanoparticles Zn0.7Ni0.15Cu0.15Fe2O4 using the co-precipitation method
Authors: Sagala L P S , Humaidi S , Tarigan K , Soehada A M S , Sebayang P
Published: May 2021

This research was conducted to see the nanostructure and magnetic properties of nanoparticle Zn0.7Ni0.15Cu0.15Fe2O4. Zn0.7Ni0.15Cu0.15Fe2O4 has been successfully synthesized at 100°C using co-precipitation method. After synthesized, it was dried at 80°C. The second step, nanoparticle powder was characterised by X-Ray Diffraction (XRD) to determine the structure and phases formation of Zn0.7Ni0.15Cu0.15Fe2O4. FE-SEM was used to analyze the morphology of Zn0.7Ni0.15Cu0.15Fe2O4. To find out the elements contained in the sample, EDAX testing was conducted. X-Ray Diffraction (XRD) results showed that Zn0.7Ni0.15Cu0.15Fe2O4 in the shape of cubic spinel with the main peak at (311). There was a hematite phase (Fe2O3) with low intensity. Zn0.7Ni0.15Cu0.15Fe2O4 crystallizes well indicated by 2θ = 35.385°. The crystal size on the nano scale has been formed, which was 14.5087 nm. The FE-SEM results showed that the morphology of Zn0.7Ni0.15Cu0.15Fe2O4 was spherical and has agglomerated. The elements contained in these nanoparticles were Zn, Ni, Cu, Fe and O. There were no other impurities indicated from the EDAX test results.This indicated that the elements contained were already in accordance with the chemical formula. Magnetic hysteresis curves showed that Zn0.7Ni0.15Cu0.15Fe2O4 was softmagnetic.
Prediction of the height and period of sea waves in the coastal waters of Meulaboh, Aceh Province, Indonesia
Authors: Setiawan I , Yuni S M , Miftahuddin M , Ilhamsyah Y
Published: May 2021

This research examines the prediction of sea waves in the coastal waters of Meulaboh. The sea wave prediction are based on the 2015-2019 monsoons in the coastal waters of Meulaboh. The method used is an empirical equation that consist of wave parameters, i.e., significant wave height Hmo
and peak period Tp
. The sea wave prediction generate an average of the height and period of the sea waves of 0.7 m; 5 s in the Southwest direction. Based on the prediction, it shows that the sea waves in Meulaboh coastal waters are influenced by the Southwest wind that blows towards the coast from the Indian Ocean.
Extraction of kinetic energy in the part of Aceh Waters
Authors: Siregar A M , Ikhwan M , Haditiar Y , Wafdan R , Muhammad M , Ramli M , Muchlisin Z A , Rizal S
Published: May 2021

This research is a preliminary study regarding the extraction of kinetic energy from sea tides in Aceh’s waters. Aceh’s waters have a reasonably long coastline (> 2000 km), which has not been studied and utilized much. The extraction of kinetic energy from ocean tides is based on the speed of currents and turbines. Hydrodynamic verification is based on sea-level data from TPXO7.2 and Geospatial Indonesia Agency (GIA). The tidal data is sufficiently consistent with the verification data from TPXO7.2 and GIA. Based on the results, the model succeeded in accurately describing the hydrodynamics currents in the research domain based on comparative verification data. The velocity of M2 tidal flow in the waters of West Aceh is relatively low, particularly in the waters of Ulee Lheue is 0.018 m/s while in Calang waters, it is 0.025 m/s. The maximum tidal energy in Ulee Lheue waters is 9, 142 × 10−2 kW, with a daily power of 4.63 × 103 kW. In Calang waters, the maximum energy is 2, 449 × 10−1 kW, while the daily power is 1, 0167 × 104 kW. These results indicate that Calang Waters (Aceh Jaya district) had more significant potential for tidal currents and energy than Ulee Lheue Waters (Aceh Besar district).