bluuebunny/crossref_metadata_2025 huggingface dataset:
Machine learning-based prediction model using clinico-pathologic factors for papillary thyroid carcinoma recurrence
Authors: Park Young Min , Lee Byung-Joo
Published: March 2021

This study analyzed the prognostic significance of clinico-pathologic factors, including the number of metastatic lymph nodes (LNs) and lymph node ratio (LNR), in patients with papillary thyroid carcinoma (PTC), and attempted to construct a disease recurrence prediction model using machine learning techniques. We retrospectively analyzed clinico-pathologic data from 1040 patients diagnosed with PTC between 2003 and 2009. We analyzed clinico-pathologic factors related to recurrence through logistic regression analysis. Among the factors that we included, only sex and tumor size were significantly correlated with disease recurrence. Parameters such as age, sex, tumor size, tumor multiplicity, ETE, ENE, pT, pN, ipsilateral central LN metastasis, contralateral central LNs metastasis, number of metastatic LNs, and LNR were input for construction of a machine learning prediction model. The performance of five machine learning models related to recurrence prediction was compared based on accuracy. The Decision Tree model showed the best accuracy at 95%, and the lightGBM and stacking model together showed 93% accuracy. Among those factors mentioned above, LNR and contralateral LN metastasis were used as important features in all machine learning prediction models. We confirmed that all machine learning prediction models showed an accuracy of 90% or more for predicting disease recurrence in PTC. LNR and contralateral LN metastasis were used as important features for constructing a robust machine learning prediction model. In the future, we have a plan to perform large-scale multicenter clinical studies to improve the performance of our prediction models and verify their clinical effectiveness.
Computational fluid dynamics (CFD) simulation analysis on retinal gas cover rates using computational eye models
Authors: Gozawa Makoto , Takamura Yoshihiro , Aoki Tomoe , Iwasaki Kentaro , Inatani Masaru
Published: March 2021

We investigated the change in the retinal gas cover rates due to intraocular gas volume and positions using computational eye models and demonstrated the appropriate position after pars plana vitrectomy (PPV) with gas tamponade for rhegmatogenous retinal detachments (RRDs). Computational fluid dynamic (CFD) software was used to calculate the retinal wall wettability of a computational pseudophakic eye models using fluid analysis. The model utilized different gas volumes from 10 to 90%, in increments of 10% to the vitreous cavity in the supine, sitting, lateral, prone with closed eyes, and prone positions. Then, the gas cover rates of the retina were measured in each quadrant. When breaks are limited to the inferior retina anterior to the equator or multiple breaks are observed in two or more quadrants anterior to the equator, supine position maintained 100% gas cover rates in all breaks for the longest duration compared with other positions. When breaks are limited to either superior, nasal, or temporal retina, sitting, lower temporal, and lower nasal position were maintained at 100% gas cover rates for the longest duration, respectively. Our results may contribute to better surgical outcomes of RRDs and a reduction in the duration of the postoperative prone position.
Reduced serum levels of anti-Mullerian hormone is a putative biomarker of early knee osteoarthritis in middle-aged females at menopausal transition
Authors: Sasaki Eiji , Chiba Daisuke , Ota Seiya , Kimura Yuka , Sasaki Shizuka , Yamamoto Yuji , Oishi Maika , Iino Kaori , Ando Masataka , Tsuda Eiichi , Ishibashi Yasuyuki
Published: March 2021

A recent epidemiological study revealed that the highest prevalence of early knee osteoarthritis (OA) was observed in females aged ≥ 50 years. The major causal factor of early knee OA was sex. Despite the relevance of estrogen in evaluating chondral and bone metabolism in OA, it is not easily clinically monitored because irregular menstrual cycles induce unstable female hormone patterns during menopausal transitions. Anti-Mullerian hormone (AMH) has been found to be a new stable biomarker to predict menopause. This study aimed to investigate the association between menopausal transition and early knee OA by using serum biomarkers, with special focus on AMH. A total of 518 female volunteers who participated in the Iwaki cohort study were enrolled and divided into pre-menopause and post-menopause groups. Weight-bearing anterior–posterior knee radiographs were classified by Kellgren–Lawrence (KL) grade, and grade ≥ 2 was defined as radiographic knee OA. In participants with KL grades 0 and 1, early knee OA was defined by Luyten’s criteria. AMH, luteinizing hormone, follicle-stimulating hormone, estradiol (pg/ml), prolactin, and testosterone were measured on the female hormones. Bone mineral density at a distal radius was measured. The predictive power of female hormones for early knee OA was estimated by ROC analysis (comparison of area under curve, AUC) and regression analysis. Fifty-two participants (10.0%) were diagnosed with early knee OA and 204 (39.4%) with radiographic knee OA. In 393 (75.9%) females, menopause began. From the ROC analysis in pre-menopausal females, cutoff value of AMH for detecting early knee OA was 0.08 ng/ml (area under curve (AUC), 0.712; 95% CI, 0.527–0.897; p value, 0.025; odds ratio, 8.28). AUCs of other female hormones did not reach the level of AMH (range, 0.513 of prolactine to 0.636 of estradiol). Logistic regression analysis focusing on AMH reduction at menopausal transition showed that the related AMH below 0.08 ng/ml was significantly related to the presence of early knee OA (p = 0.035; odds ratio, 5.55). Reduced serum levels of AMH in middle-aged females were correlated with the presence of early knee OA, which might be a useful serum biomarker.
Author Correction: Evolution from adherent to suspension: systems biology of HEK293 cell line development
Authors: Malm Magdalena , Saghaleyni Rasool , Lundqvist Magnus , Giudici Marco , Chotteau Veronique , Field Ray , Varley Paul G. , Hatton Diane , Grassi Luigi , Svensson Thomas , Nielsen Jens , Rockberg Johan
Published: March 2021

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Assessment of transient changes in oxygen diffusion of single red blood cells using a microfluidic analytical platform
Authors: Chng Kevin Ziyang , Ng Yan Cheng , Namgung Bumseok , Tan Justin Kok Soon , Park Soyeon , Tien Sim Leng , Leo Hwa Liang , Kim Sangho
Published: March 2021

Red blood cells (RBCs) capability to deliver oxygen (O2) has been routinely measured by P50. Although this defines the ability of RBCs to carry O2 under equilibrium states, it cannot determine the efficacy of O2 delivery in dynamic blood flow. Here, we developed a microfluidic analytical platform (MAP) that isolates single RBCs for assessing transient changes in their O2 release rate. We found that in vivo (biological) and in vitro (blood storage) aging of RBC could lead to an increase in the O2 release rate, despite a decrease in P50. Rejuvenation of stored RBCs (Day 42), though increased the P50, failed to restore the O2 release rate to basal level (Day 0). The temporal dimension provided at the single-cell level by MAP could shed new insights into the dynamics of O2 delivery in both physiological and pathological conditions.
Author Correction: A generic approach to study the kinetics of liquid–liquid phase separation under near-native conditions
Authors: Van Lindt Joris , Bratek-Skicki Anna , Nguyen Phuong N. , Pakravan Donya , Durán-Armenta Luis F. , Tantos Agnes , Pancsa Rita , Van Den Bosch Ludo , Maes Dominique , Tompa Peter
Published: March 2021

A Correction to this paper has been published: https://doi.org/10.1038/s42003-021-01853-4.
Concluding remarks: Faraday Discussion on air quality in megacities
Authors: Gen Masao , Zhou Liyuan , Zhang Ruifeng , Chan Chak K.
Published: March 2021

This paper provides a brief summary of the virtual Faraday Discussion: Air Quality in Megacities.
Control of light–valley interactions in 2D transition metal dichalcogenides with nanophotonic structures
Authors: Li Shasha , Wang Hao , Wang Jing , Chen Huanjun , Shao Lei
Published: March 2021

Valley pseudospin of 2D transition-metal dichalcogenides is promising for information technologies, but its robust manipulation is challenging. This minireview highlights recent progress on using nanophotonic strategies to address this challenge.
Optically tunable ultra-fast resistive switching in lead-free methyl-ammonium bismuth iodide perovskite films
Authors: Poddar Swapnadeep , Zhang Yuting , Zhu Yiyi , Zhang Qianpeng , Fan Zhiyong
Published: March 2021

Optical switching with sub-threshold electrical stimulation was observed in lead-free methyl ammonium bismuth iodide perovskite films. The Re-RAM device also exhibited an ultra-fast electrical switching speed of 10 ns.
Controlling the crystallinity and solubility of functional PCL with efficient post-polymerisation modification
Authors: Clamor Cinzia , Cattoz Beatrice N. , Wright Peter M. , O'Reilly Rachel K. , Dove Andrew P.
Published: March 2021

Varying the size of an alkyl side-chain group, installed by thiol–ene addition of alkylthiols to poly(ε-allyl caprolactone), the semi-crystallinity and lipophilicity of functional PCLs could be modulated to achieve divergent physico-chemical properties.
Thermal-stability of the enhanced piezoelectric, energy storage and electrocaloric properties of a lead-free BCZT ceramic
Authors: Merselmiz Soukaina , Hanani Zouhair , Mezzane Daoud , Razumnaya Anna G. , Amjoud M'barek , Hajji Lahoucine , Terenchuk Svitlana , Rožič Brigita , Luk'yanchuk Igor A. , Kutnjak Zdravko
Published: March 2021

High-thermal stability of the recovered energy density and significant electrocaloric temperature change over a broad temperature span in a lead-free BCZT ceramic.
Ligand-based pharmacophore modeling, virtual screening and biological evaluation to identify novel TGR5 agonists
Authors: Zhao Shizhen , Li Xinping , Peng Wenjing , Wang Le , Ye Wenling , Zhao Yang , Yin Wenbo , Chen Wei-Dong , Li Weiguo , Wang Yan-Dong
Published: March 2021

The ligand-based virtual screening combined with pharmacophore mapping and molecular docking was performed to identify novel nonsteroidal TGR5 agonists.
MS-based proteomics for comprehensive investigation of proteinO-GlcNAcylation
Authors: Xu Senhan , Sun Fangxu , Tong Ming , Wu Ronghu
Published: March 2021

ProteinO-GlcNAcylation plays critical roles in mammalian cells, and here we review MS-based proteomics methods for comprehensive and site-specific analysis of proteinO-GlcNAcylation, ranging from enrichment, fragmentation, to quantification.
Benign synthesis of fused-thiazoles with enone-based natural products and drugs for lead discovery
Authors: Alnufaie Rawan , Ali Mohamad Akbar , Alkhaibari Ibrahim S. , Roy Subrata , Day Victor W. , Alam Mohammad A.
Published: March 2021

In an effort to synthesize a library of bioactive molecules, we present an efficient synthesis of fused-thiazole derivatives of natural products and approved drugs by using an environmentally usable solvent, acetic acid, and without any external reagent.
A novel method to detect mutation in DNA by utilizing exponential amplification reaction triggered by the CRISPR-Cas9 system
Authors: Song Jayeon , Kim Soohyun , Kim Hyo Yong , Hur Kyung Hoon , Kim Yoosik , Park Hyun Gyu
Published: March 2021

We, herein, describe a novel method to detect mutation in DNA by utilizing exponential amplification reaction (EXPAR) triggered by clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9, called CRISPR–EXPAR.
PtPd nanoframes derived from Pd@PdPt core–shell rhombic dodecahedrals with excellent catalytic performance toward methanol oxidation
Authors: Ren Yangyang , Li Chuanliang , Li Baosong , Gao Fan , Zhang Xinghua , Yang Xiaojing , Li Lanlan , Lu Zunming , Yu Xiaofei
Published: March 2021

PtPd nanoframes with excellent catalytic properties were obtained by etching Pd@PdPt core–shell RDs with Fe3+ in an acid environment.
Photoinduced triiodide-mediated [3 + 2] cycloaddition of N-tosyl aziridines and alkenes
Authors: Li Yuanbo , Chen Fan , Zhu Shengqing , Chu Lingling
Published: March 2021

A photoinduced triiodide-mediated [3 + 2] cycloaddition of N-Ts aziridines and alkenes is described herein. This operationally simple protocol enables regioselective access to a wide range of substituted pyrrolidines under mild-free conditions.
Amide-functionalised phosphonium-based ionic liquids as ligands for rhodium(iii) extraction
Authors: Yoshida Wataru , Goto Masahiro
Published: March 2021

Novel amide-functionalised phosphonium-based ionic liquid can extract rhodium(iii) efficiently.
A Longitudinal Comparison of Environmental Sound Recognition in Adults With Hearing Aids Before and After Cochlear Implantation
Authors: Harris Michael S. , Moberly Aaron C. , Hamel Ben L. , Vasil Kara , Runge Christina L. , Riggs William J. , Shafiro Valeriy
Published: March 2021

Purpose

The aims of this study were (a) to longitudinally assess environmental sound recognition (ESR) before and after cochlear implantation in a sample of postlingually deafened adults and (b) to assess the extent to which spectro-temporal processing abilities influence ESR with cochlear implants (CIs).

Method

In a longitudinal cohort study, 20 postlingually deafened adults were tested with hearing aids on the Familiar Environmental Sound Test–Identification and AzBio sentences in quiet pre-CI and 6 months post-CI. A subset of 11 participants were also tested 12 months post-CI. Pre-CI spectro-temporal processing was assessed using the Spectral-temporally Modulated Ripple Test.

Results

Average ESR accuracy pre-CI (
M
= 63.60%) was not significantly different from ESR accuracy at 6 months (
M
= 65.40%) or 12 months (
M
= 69.09%) post-CI. In 11 participants (55%), however, ESR improved following implantation by 10.91 percentage points, on average. Pre-CI ESR correlated moderately and significantly with pre-CI and 12-month post-CI AzBio scores, with a trend toward significance for AzBio performance at 6 months. Pre-CI spectro-temporal processing was moderately associated with ESR at 6 and 12 months post-CI but not with speech recognition post-CI.

Conclusions

The present findings failed to demonstrate an overall significant improvement in ESR following implantation. Nevertheless, more than half of our sample showed some degree of improvement in ESR. Several environmental sounds were poorly identified both before and after implantation. Spectro-temporal processing ability prior to implantation appears to predict postimplantation performance for ESR. These findings indicate the need for greater attention to ESR following cochlear implantation and for developing individualized targets for ESR rehabilitation.

Supplemental Material

https://doi.org/10.23641/asha.13876745
Low‐complexity neuron for fixed‐point artificial neural networks with ReLU activation function in energy‐constrained wireless applications
Authors: Chin Wen‐Long , Zhang Qinyu , Jiang Tao
Published: March 2021

This work introduces an efficient neuron design for fixed‐point artificial neural networks with the rectified linear unit (ReLU) activation function for energy‐constrained wireless applications. The fixed‐point binary numbers and ReLU activation function are used in most application‐specific integrated circuit designs and artificial neural networks (ANN), respectively. It is well known that, owing to involved computation intensive tasks, the computational burden of ANNs is ultra heavy. Consequently, many practitioners and researchers are discovering the ways to reduce implementation complexity of ANNs, particularly for battery‐powered wireless applications. For this, a low‐complexity neuron to predict the sign bit of the input of the non‐linear activation function, ReLU, by employing the saturation characteristics of the activation function is proposed. According to our simulation results based on random data, computation overhead of a neuron using the proposed technique can be saved by a ratio of 29.6% compared to the conventional neuron using a word length of 8 bits without apparently increasing the prediction error. A comparison of the proposed algorithm with the popular 16‐bit fixed‐point format of the convolutional network, AlexNet, indicates that the computation can be saved by 48.58% as well.
A switched‐capacitor battery equalization method for improving balancing speed
Authors: Sun Wenbin , Li Yanling , Liu Lizhou , Mai Ruikun
Published: March 2021

The switched‐capacitor equalizer (SCE) has a broad application prospect because of its small size, easy control, and implementation. However, the conventional SCE by shifting energy between two adjacent cells usually has a lower balancing speed the number of imbalanced battery cells increases. Therefore, an automatic SCE is proposed to improve the balancing speed for a long battery string. The main advantage of the proposed method is taking the highest‐voltage battery cell as the source for balancing. By controlling the MOSFETs alternately with one pair of complementary pulse width modulation signals, the energy can be directly delivered from the highest‐voltage battery cell to other lower‐voltage ones, to avoid the frequent energy inflow or outflow from the same battery cell. A prototype for four lithium battery cells is implemented, and the comparisons between the proposed SCE and other SCEs in simulation and experiment are presented. Results show that the proposed SCE topology exhibits an obvious improvement in balancing speed at different initial voltage mismatch distributions.
Modeling of supersonic jet behavior in the vacuum refining process
Authors: Sheng Zhonghua , Feng Lianghua , Liu Kun , Yang Bin , Kong Lingzhong
Published: March 2021

There are two problems to be solved in the numerical simulation of the top blown oxygen vacuum refining process. (1) The two-equation turbulence models underpredict the turbulence mixing shear process for high-temperature gradient jet flows. (2) The high compressibility of the jet in a low vacuum environment. In this study, the SST k-ω turbulence model is modified by the composite function of the compressibility factor and the total temperature gradient. Based on the experimental model of the Kotani vacuum jet, the modified turbulence model was used to simulate the supersonic jet behavior of oxygen lance at different ambient temperatures. The reliability of the model is verified by the semi-empirical formula of Ito and Muchi. The simulation results show that the entrainment rate is an important inducing factor. The potential core length and the supersonic core length at the temperature of 1800 K are 2.5 times and 2.0 times that at the temperature of 285 K, respectively. Besides, based on the ejection model established by Ricou and Spalding, the calculation formula of turbulence entrainment rate at different ambient temperatures is obtained. This research work will benefit greatly to the supersonic jet behavior in Vacuum Refining.
Diagnostik der Spondylodiszitis
Authors: Leiderer Miriam , Viezens Lennart , Henes Frank Oliver
Published: March 2021

Die Spondylodiszitis gilt in der westlichen Welt als ein häufig verzögert diagnostiziertes Krankheitsbild. Jedoch ist eine frühe Diagnosestellung entscheidend, um die Therapie zeitgerecht einzuleiten und so Komplikationen zu vermeiden. Die radiologische Bildgebung spielt dabei – besonders im Frühstadium – eine zentrale Rolle bei der Abgrenzung zu anderen Erkrankungen der Wirbelsäule.
Die Bedeutung der Ethik bei der Nutzung Künstlicher emotionaler Intelligenz in der Psychiatrie – ein ethischer Diskurs
Authors: Rüther Eckart , Hajak Göran , Huber Lukas , Zech Katharina , Trojan Andreas
Published: March 2021

Der ethische Diskurs spricht nachfolgende Aspekte an: Wofür brauchen wir Ethik? Disposition des Menschen zur Moral, Naturethik. Moral als gesellschaftliche Norm. Moral zum Erhalt einer un-, übermenschlichen Machtstruktur. Moral als Artefakt des Gehirns, als behindernd für neue Entwicklungen. Einheit von Ethik und Ästhetik. „Zoon politikon“, „Robinson Crusoe“. Benötigt eine Künstliche Intelligenz (KI) eine neue Ethik? Eigenschaften einer KI, entwickelt für die Einsamkeit, als Dienender oder mit christlicher Software, Gruppenfähigkeit, eigenen Emotionen, Bewusstsein und eigener Ethik, als Ergänzung. Soll KI zugemutet werden, menschliche Emotionen zu haben? Emotionale Intelligenz, Sprache als Vermittler von Emotionen und Empathie, Mentalisierungsfähigkeit, Künstliche (generale) emotionale Intelligenz, „Terminator“, „L’Eve future“.
Postoperative Hypokalzämie – die häufigste Komplikation der endokrinen Chirurgie der Halsregion: Akutes Management
Authors: Lammert Anne , Nowak Kai , Weber Roland , Rotter Nicole , Schölch Sebastian , Krämer Bernhard K. , Lammert Alexander
Published: March 2021

Hintergrund In Deutschland sind jährlich ca. 8000 Patienten nach Eingriffen an Schilddrüse, Nebenschilddrüse und Larynx von einem behandlungsbedürftigen postoperativen Hypoparathyreoidismus betroffen. Die Patienten leiden im Akutstadium der Hypokalzämie an Parästhesien und nicht selten auch über viele Jahre hinweg unter der Angst vor einem erneuten körperlichen Kontrollverlust bei schweren postoperativen Tetanien.

Fragestellung/Ziel Ziel dieser Arbeit ist es, für die Wichtigkeit des Managements des postoperativen Hypoparathyreoidismus in der endokrinen Chirurgie der Halsregion zu sensibilisieren, einen praktikablen Diagnostikpfad aufzuzeigen und so die effektive Therapie zu ermöglichen.

Material und Methode Narratives Review mit Auswertung und Diskussion von relevanten klinischen Originalarbeiten und Expertenempfehlungen.

Ergebnisse und Diskussion Die frühzeitige postoperative Diagnosestellung nach Eingriffen im Halsbereich mittels Bestimmung von Kalzium und Parathormon ermöglicht den rechtzeitigen Therapiebeginn. Aktives Vitamin D sichert dabei die Resorption von Kalzium, sodass nur eine kombinierte Gabe von Vitamin D und Kalzium in der Lage ist, den postoperativen Kalziumabfall zu mitigieren oder ganz zu verhindern.

Schlussfolgerung Eine Arbeitsanweisung (SOP) zur Diagnostik und Therapie der postoperativen Hypokalzämie sollte in jeder Klinik etabliert werden. Ein entsprechender Entwurf wurde in die Arbeit aufgenommen, damit Diagnose- und Therapiepfad effektiv an lokale Gegebenheiten angepasst werden können.
The phenomena of concentration and cavitation in the Riemann solution for the isentropic zero-pressure dusty gasdynamics
Authors: Chaturvedi Rahul Kumar , Singh L. P.
Published: March 2021

The aim of the present paper is to investigate the concentration and cavitation phenomenon in the solution of the Riemann problem (RP) to the pressureless isentropic Euler equations for the dusty gas flow by using the two parameter flux approximation. The similar solution of the RP for dusty gas flow is obtained. The formation of δ-shock and vacuum state in the flow field is discussed. Also, it is shown that the solution, containing two shock waves, of the RP to the isentropic Euler equations for dusty gas converges to the δ-shock wave solution of the transport equations and the solution, containing two rarefaction waves, of the RP converges to the vacuum state solution of the transport equations.
Deciphering osteoconductive surface charge effects in sintered hydroxyapatite via piezoresponse force microscopy
Authors: Han Youngjoon , Ryu Jeongjae , Oh Chungik , Kim Soyeon , Schiffer Andreas , Killgore Jason P. , Hong Seungbum
Published: March 2021

Hydroxyapatite (HAp), a main constituent of the cortical bone, retains a large surface charge that plays a critical role in the regeneration of bones, whose source remains an enigma. Here, we used multi-eigenmode piezoresponse force microscopy via Pearson correlation and conducted multiscale material analysis to independently measure the piezoelectric coefficient and the surface charge density of HAp. Quantitative comparison was conducted between the measured surface charge density and the conceptual values computed for all possible candidates of the surface charging such as piezoelectricity, chemically induced surface charging, flexoelectricity, and defect dipole moment. The results presented Ca2+ ions released during local calcium orthophosphate phase transition at the surface as the main source of the surface charging. Further analysis showed that the ion concentration was modulable using a charged conductive tip, implying that the interstitial ions are mobile within the HAp matrix. In this work, we developed a novel method to measure the effective surface charge density of arbitrary material systems, thereby facilitating the investigation of biophysical phenomena related to surface electromechanics. Most importantly, the research promotes a new understanding of the origin of osteoconduction observed in past works conducted on HAp.
A theoretical model for radiation heat conduction between deuterium–tritium fuel and a high-Z pusher in volume ignition in inertial confinement fusion
Authors: Xu Rui-Hua , Zhao Ying-Kui
Published: March 2021

Volume ignition, in which fuel is usually surrounded by pushers made from high-Z materials, is an approach to inertial confinement fusion. High-Z pushers have high albedos, which means that they can re-radiate most of the radiation coming from the hot fuel. Hence, it is beneficial to realize ignition at lower temperatures. We develop a theoretical model comprising a set of coupled equations to model the radiation heat conduction between the hot fuel and the high-Z pusher. We then investigate the dependence of the albedo of the high-Z pusher on the state of the hot fuel. The results of our model show good consistency with numerical simulations. Furthermore, the physics of the radiation heat conduction between the hot fuel and the high-Z pusher in volume ignition is elucidated, which is important for follow-up studies of the critical values for volume ignition and for obtaining a physical picture of fusion burning. The model can also provide some theoretical basis for the design of double-shell targets and energy targets.
Energy budget analysis and neutral curve characteristics for the linear instability of Couette–Poiseuille flow
Authors: K. Srinivas Kirthy , Diwan Sourabh S.
Published: March 2021

Here, we present some interesting new results on the linear modal stability of the Couette–Poiseuille flow (CPF), by numerically solving the Orr–Sommerfeld equation within the temporal framework. We provide a mechanistic explanation to the well-known result that the upper plate movement causes progressive stabilization of the CPF. The temporal energy budget reveals appearance of a region of negative energy production with plate movement, which is located near the plate that has a higher relative velocity in the direction of the bulk flow. This has a negative contribution to the integral production term, which, along with the expectation that energy dissipation is nominally constant (to leading order) at a given Reynolds number (Re), reduces the growth rate of kinetic energy, thereby causing flow stabilization with an increase in plate speed. Next, we compare the linear stability portrait of the CPF for positive and negative plate speeds and find that the upper and lower neutral branches in the frequency-Re plane cross over each other (to form a “loop”) for a certain range of negative plate speeds. Interestingly, this behavior is not seen for positive plate speeds. At high Re and small plate speeds (positive/negative), we observe that the CPF supports an additional unstable mode manifested in the neutral curves as a bifurcation of the unstable region into primary and secondary regions. The secondary unstable mode is found to be sufficiently distinct in character from the primary mode. These results contribute to the contemporary efforts to better understand the stability of the CPF.
Biofunctionalization of carbon nanotubes for reversible site-specific protein immobilization
Authors: Jorde Lara , Li Zehao , Pöppelwerth Adrian , Piehler Jacob , You Changjiang , Meyer Carola
Published: March 2021

Carbon nanotubes (CNTs) emerge as biosensors due to their extraordinary electrical transport properties. Such applications depend on interfacing proteins with CNTs in an oriented manner while maintaining their structural and functional integrity, opening versatile opportunities for one-dimensional alignment and high-sensitivity sensing of protein interactions and conformational dynamics. Here, we devised a novel surface architecture for reversible protein immobilization on CNTs via a short peptide tag for fabrication of reusable biosensors for multiple protein analysis. To this end, we conjugated pyrene-poly(ethylene glycol) with tris-nitrilotriacetic acid (Py-PEG-tris-NTA) for site-specific immobilization of oligohistidine(His)-tagged proteins. We demonstrate spontaneous self-assembly of Py-PEG-tris-NTA on CNTs and graphene, as well as specific capturing of His-tagged green fluorescent protein after loading the NTA chelators with Ni(II) ions. The protein binding capacity of tris-NTA-functionalized CNTs could be restored by an imidazole wash, allowing for repeated immobilization cycles. Reflectance interference spectroscopy and fluorescence lifetime analysis confirmed a specific and reversible binding of proteins on CNT-coated silica substrates as well as close interfacing to the CNT surface.
Spatial and temporal Taylor’s law in 1D chaotic maps
Authors: Kojima Hiroki , Mitsui Yuzuru , Ikegami Takashi
Published: March 2021

By using low-dimensional chaotic maps, the power-law relationship established between the sample mean and variance called Taylor’s Law (TL) is studied. In particular, we aim to clarify the relationship between TL from the spatial ensemble (STL) and the temporal ensemble (TTL). Since the spatial ensemble corresponds to independent sampling from a stationary distribution, we confirm that STL is explained by the skewness of the distribution. The difference between TTL and STL is shown to be originated in the temporal correlation of a dynamics. In case of logistic and tent maps, the quadratic relationship in the sample mean and variance, called Bartlett’s law, is found analytically. On the other hand, TTL in the Hassell model can be well explained by the chunk structure of the trajectory, whereas the TTL of the Ricker model has a different mechanism originated from the specific form of the map.
Acoustic imaging by three-dimensional acoustic Luneburg meta-lens with lattice columns
Authors: Kim Jung-Woo , Lee Seong-Jin , Jo Jun-Yeong , Wang Semyung , Kim Sang-Hoon
Published: March 2021

A three-dimensional acoustic Luneburg meta-lens has the advantage of refracting sound waves for all incident angles and focusing higher sound pressure compared to a two-dimensional lens. The lens made of plastic with a diameter of 120 mm was designed with thousands of lattice column-shaped meta-atoms to maintain its three-dimensional shape. The lens's three-dimensional focusing performance and acoustic imaging were simulated and measured in the frequency range of 5 kHz–20 kHz. The omnidirectional property was confirmed by rotating the lens to change the incident angle and measuring the sound pressure. The development of these spherical Luneburg meta-lenses is expected to improve the performance of devices that require acoustic focusing.
Enhancing positron production using front surface target structures
Authors: Jiang S. , Link A. , Canning D. , Fooks J. A. , Kempler P. A. , Kerr S. , Kim J. , Krieger M. , Lewis N. S. , Wallace R. , Williams G. J. , Yalamanchili S. , Chen Hui
Published: March 2021

We report a target design which produced a substantial gain in relativistic electron-positron pair production using high-intensity lasers and targets with large-scale micro-structures on their surface. Comparing to an unstructured target, a selected Si microwire array target yielded a near 100% increase in the laser-to-positron conversion efficiency and produced a 10 MeV increase in the average emitted positron energy under nominally the same experimental conditions. We had established a multi-scale particle-in-cell simulation scheme to simulate both the laser absorption and the subsequent pair productions in a thick metal target. The experimental results are supported by the simulations demonstrating the performance increase is due to a higher conversion efficiency of laser energy into electrons with kinetic energies greater than 10 MeV due to enhanced direct laser acceleration of electrons enabled by the microwire array.
Achieving criticality for reservoir computing using environment-induced explosive death
Authors: Mandal Swarnendu , Shrimali Manish Dev
Published: March 2021

The network of oscillators coupled via a common environment has been widely studied due to its great abundance in nature. We exploit the occurrence of explosive oscillation quenching in a network of non-identical oscillators coupled to each other indirectly via an environment for efficient reservoir computing. At the very edge of explosive transition, the reservoir achieves criticality maximizing its information processing capacity. The efficiency of the reservoir at different configurations is determined by the computational accuracy for different tasks performed by it. We analyze the dependence of accuracy on the dynamical behavior of the reservoir in terms of an order parameter symbolizing the desynchronization of the system. We found that the reservoir achieves the criticality in the steady-state region right at the edge of the hysteresis area. By computing the entropy of the reservoir for different tasks, we confirm that maximum accuracy corresponds to the edge of chaos or the edge of stability for this reservoir.
Single-parameter aging in a binary Lennard-Jones system
Authors: Mehri Saeed , Ingebrigtsen Trond S. , Dyre Jeppe C.
Published: March 2021

This paper studies physical aging by computer simulations of a 2:1 Kob–Andersen binary Lennard-Jones mixture, a system that is less prone to crystallization than the standard 4:1 composition. Starting from thermal-equilibrium states, the time evolution of the following four quantities is monitored by following up and down jumps in temperature: potential energy, virial, average squared force, and the Laplacian of the potential energy. Despite the fact that significantly larger temperature jumps are studied here than in typical similar experiments, to a good approximation, all four quantities conform to the single-parameter-aging scenario derived and validated for small jumps in experiments [T. Hecksher, N. B. Olsen, and J. C. Dyre, J. Chem. Phys. 142, 241103 (2015)]. As a further confirmation of single-parameter aging with a common material time for the four different quantities monitored, their relaxing parts are found to be almost identical for all temperature jumps.
Intermolecular interactions in optical cavities: An ab initio QED study
Authors: Haugland Tor S. , Schäfer Christian , Ronca Enrico , Rubio Angel , Koch Henrik
Published: March 2021

Intermolecular bonds are weak compared to covalent bonds, but they are strong enough to influence the properties of large molecular systems. In this work, we investigate how strong light–matter coupling inside an optical cavity can modify intermolecular forces and illustrate the varying necessity of correlation in their description. The electromagnetic field inside the cavity can modulate the ground state properties of weakly bound complexes. Tuning the field polarization and cavity frequency, the interactions can be stabilized or destabilized, and electron densities, dipole moments, and polarizabilities can be altered. We demonstrate that electron–photon correlation is fundamental to describe intermolecular interactions in strong light–matter coupling. This work proposes optical cavities as a novel tool to manipulate and control ground state properties, solvent effects, and intermolecular interactions for molecules and materials.
Supercooled liquid-like dynamics in water near a fully hydrated titania surface: Decoupling of rotational and translational diffusion
Authors: Agosta Lorenzo , Dzugutov Mikhail , Hermansson Kersti
Published: March 2021

We report an ab initio molecular dynamics (MD) simulation investigating the effect of a fully hydrated surface of TiO2 on the water dynamics. It is found that the universal relation between the rotational and translational diffusion characteristics of bulk water is broken in the water layers near the surface with the rotational diffusion demonstrating progressive retardation relative to the translational diffusion when approaching the surface. This kind of rotation–translation decoupling has so far only been observed in the supercooled liquids approaching glass transition, and its observation in water at a normal liquid temperature is of conceptual interest. This finding is also of interest for the application-significant studies of the water interaction with fully hydrated nanoparticles. We note that this is the first observation of rotation–translation decoupling in an ab initio MD simulation of water.
The response to external excitations in thermocapillary liquid layers
Authors: Hu Kai-Xin , Zheng Sheng , Chen Qi-Sheng
Published: March 2021

The responses to external excitations in thermocapillary liquid layers are investigated by non-modal stability theory. The maximum amplification of input signals is measured by a response function depending on the perturbation velocity and temperature. There can be rather large amplifications in subcritical flows at both small and large Prandtl numbers (Pr). For small Pr, the response increases significantly with both the Reynolds number (R) and the Biot number (Bi) but decreases with Pr. The optimal response is achieved when the perturbation is almost a spanwise wave. The response properties for the linear flow and the return flow are similar. The amplification is caused by a combination of the lift-up mechanism, Orr mechanism, and external forcing. However, for large Pr, large amplifications could only be found in the return flow, while the variations of response with Pr and Bi are opposite to those at small Pr. The optimal response propagates in the streamwise direction. The amplification is caused by the thermocapillary effect.
Aqueous films on pore surfaces mediate adsorption and transport of gases through crowded nanopores
Authors: Phan Anh , Striolo Alberto
Published: March 2021

Interactions of trapped reservoir gases within organic-rich and brine-bearing sedimentary rocks have direct relevance to many geoenergy applications. Extracting generalizable information from experimental campaigns is hindered by the fact that geological systems are extremely complex. However, modern computational tools offer the opportunity of studying systems with controlled complexity, in an effort to better understand the mechanisms at play. Employing molecular dynamics, we examine here adsorption and transport of gases containing CH4 and either CO2 or H2S within amorphous silica nanopores filled with benzene. We explicitly quantify the effect of small amounts of water/brines at geological temperature and pressure conditions. Because of wetting, the presence of brines lessens the adsorption capacity of the aromatic-filled pore. The simulation results show salt-specific effects on the transport properties of the gases when either KCl or CaCl2 brines are considered, although adsorption was not affected. The acid gases considered either facilitate or hinder CH4 transport depending on whether they are more or less preferentially adsorbed within the pore as compared to benzene, and this effect is mediated by the presence of water/brines. Our simulation results could be used to extract thermodynamic quantities that in the future will help to optimize transport of various gases through organic-rich and brine-bearing sedimentary rocks, which is likely to have a positive impact on both hydrocarbon production and carbon sequestration applications. As a first step, a phenomenological model is presented here, which allows one to predict permeability based on interatomic energies.
Vibronic interaction in trans-dichloroethene studied by vibration- and angle-resolved photoelectron spectroscopy using 19–90 eV photon energy
Authors: Duran Ayse T. , Powis Ivan , Holland David M. P. , Nicolas Christophe , Bozek John , Trofimov A. B. , Grigoricheva E. K. , Skitnevskaya A. D.
Published: March 2021

Valence photoelectron spectra and photoelectron angular distributions of trans-dichloroethene have been measured with vibrational resolution at photon energies between 19 eV and 90 eV. Calculations of photoelectron anisotropy parameters, β, and harmonic vibrational modes help provide initial insight into the molecular structure. The photon energy range encompasses the expected position of the atomic Cl 3p Cooper minimum. A corresponding dip observed here in the anisotropy of certain photoelectron bands permits the identification and characterization of those molecular orbitals that retain a localized atomic Cl character. The adiabatic approximation holds for the X 2Au state photoelectron band, but vibronic coupling was inferred within the A–B–C and the D–E states by noting various failures of the Franck–Condon model, including vibrationally dependent β-parameters. This is further explored using the linear vibronic coupling model with interaction parameters obtained from ab initio calculations. The A/B photoelectron band is appreciably affected by vibronic coupling, owing to the low-lying conical intersection of the A 2Ag and B 2Bu states. The C 2Bg band is also affected, but to a lesser extent. The adiabatic minima of the D 2Au and E 2Ag states are almost degenerate, and the vibronic interaction between these states is considerable. The potential energy surface of the D 2Au state is predicted to have a double-minimum shape with respect to the au deformations of the molecular structure. The irregular vibrational structure of the resulting single photoelectron band reflects the non-adiabatic nuclear dynamics occurring on the two coupled potential energy surfaces above the energy of their conical intersection.
Metamaterial-inspired multilayered structures optimized to enable wireless communications through a plasmasonic region
Authors: Webb Bruce A. , Ziolkowski Richard W.
Published: March 2021

Radio frequency blackout is a well-known phenomenon that happens when a plasma forms around a plasmasonic vehicle traveling through an atmosphere. This paper examines an electromagnetic metamaterial-based approach to mitigate the communication losses through the blackout plasma. A paired epsilon- and mu-negative layered meta-structure is developed that is matched to the epsilon-negative plasma, creating a low-loss passband window through it. Its ideal performance is first characterized analytically. Metamaterial inclusions are then developed to attain the required single-negative layers. Numerical simulations of the resulting realizable meta-structure verify its efficacy, confirming the analytical results and the viability of using it to achieve reasonable signal strengths through representative plasma thicknesses.
Flexible hematite (α-Fe2O3)-graphene nanoplatelet (GnP) hybrids with high thermal conductivity
Authors: Shayganpour Amirreza , Clausi Marialaura , Bayer Ilker S.
Published: March 2021

Hematite (α-Fe2O3) has several attractive properties such as corrosion resistance, catalytic activity, sensing properties, and magnetic features but also a room-temperature stable thermal conductivity of about 16 W/m K. Its use in polymer-matrix composites as a thermal performance enhancer is rather uncommon. In this study, hematite and graphene nanoplatelet (GnP) hybrids in a rubbery latex matrix were prepared and their thermal properties were characterized. The hybrids were mechanically stabilized into freestanding films by hot-pressing them into a porous cellulosic membrane. Optimization of the total filler concentration and the α-Fe2O3/GnP ratio yielded thermal interface material (TIM) films with a thermal conductivity of 8.0 W/mK. Infrared measurements showed that the TIMs significantly improved heat sink cooling and demonstrated rapid heat transfer in a system simulating stacked up electronic packing.
Acceleration of radiative recombination in quasi-2D perovskite films on hyperbolic metamaterials
Authors: Tonkaev Pavel , Anoshkin Sergey , Pushkarev Anatoly , Malureanu Radu , Masharin Mikhail , Belov Pavel , Lavrinenko Andrei , Makarov Sergey
Published: March 2021

Hyperbolic metamaterials are a family of nanophotonic architectures allowing for the unique control of photonic local density of states. Such a property makes metamaterials prospective to use them with light-emitting objects or to apply as meta-electrodes for optoelectronic devices, where the control of recombination properties plays a decisive role. On the other hand, layered quasi-2D halide perovskites (Ruddlesden–Popper phase) attract high attention due to their low cost, broadband spectral tunability, and outstanding optoelectronic properties. Here, we show how to accelerate photoluminescence with smart engineering of photonic density of states (i.e., via the Purcell effect) by depositing a perovskite film on a hyperbolic metamaterial. We experimentally confirm acceleration of radiative recombination by almost 3 times. This effect can be useful in light-emitting devices, where interplay between radiative and non-radiative channels of charge carrier recombination is crucial.
CENP-A chromatin prevents replication stress at centromeres to avoid structural aneuploidy
Authors: Giunta Simona , Hervé Solène , White Ryan R. , Wilhelm Therese , Dumont Marie , Scelfo Andrea , Gamba Riccardo , Wong Cheng Kit , Rancati Giulia , Smogorzewska Agata , Funabiki Hironori , Fachinetti Daniele
Published: March 2021

Significance

CENP-A, the histone H3 variant that forms a unique centromeric chromatin, is essential for faithful chromosome segregation during mitosis. Inability to connect the centromere to the mitotic spindle causes aneuploidy, a hallmark of many cancers. In addition to chromosome missegregation, chromosome fusions at (peri)centromeres are prevalent in cancers, but how such rearrangements arise remains unclear. Here, we identified a role for CENP-A in maintaining the integrity of centromere-associated repetitive sequences by ensuring their effective replication in human cells. In the absence of CENP-A, generation of DNA–RNA hybrids due to transcription–replication conflicts causes delayed DNA replication, centromere breakage, recombination, and chromosome translocations at centromeres. Centromeres thus possess a special mechanism to facilitate their replication and suppress chromosome translocations.
Machine learning active-nematic hydrodynamics
Authors: Colen Jonathan , Han Ming , Zhang Rui , Redford Steven A. , Lemma Linnea M. , Morgan Link , Ruijgrok Paul V. , Adkins Raymond , Bryant Zev , Dogic Zvonimir , Gardel Margaret L. , de Pablo Juan J. , Vitelli Vincenzo
Published: March 2021

Significance

Artificial intelligence holds considerable promise for transforming quantitative modeling in materials science. We illustrate this potential by developing machine-learning models of a paradigmatic class of biomaterials called active nematics. These hybrid materials can be viewed as artificial muscles composed of biological fibers and molecular motors. Here, the macroscopic coefficients characterizing energy injection by motors and material elasticity are not constant. They are unknown functions of space and time that we extract directly from experiments using neural networks. Our physics-inspired machine-learning algorithms can also forecast the evolution of these complex materials simply using image sequences from their past, without any knowledge of the governing dynamics.