bluuebunny/crossref_metadata_2025 huggingface dataset:
Accurate predictions of chaotic motion of a free fall disk
Authors: Xu Tianzhuang , Li Jing , Li Zhihui , Liao Shijun
Published: March 2021

It is important to know the accurate trajectory of a free fall object in fluid (such as a spacecraft), whose motion might be chaotic in many cases. However, it is impossible to accurately predict its chaotic trajectory in a long enough duration by traditional numerical algorithms in double precision. In this paper, we give the accurate predictions of the same problem by a new strategy, namely, the Clean Numerical Simulation (CNS). Without loss of generality, a free-fall disk in water is considered, whose motion is governed by the Andersen–Pesavento–Wang model. We illustrate that convergent and reliable trajectories of a chaotic free-fall disk in a long enough interval of time can be obtained by means of the CNS, but different traditional algorithms in double precision give disparate trajectories. Besides, unlike the traditional algorithms in double precision, the CNS can predict the accurate posture of the free-fall disk near the vicinity of the bifurcation point of some physical parameters in a long duration. Therefore, the CNS can provide reliable prediction of chaotic systems in a long enough interval of time.
A hydrogen-bonded CHF⋯HF complex: IR spectra and unusual photochemistry
Authors: Sosulin Ilya S. , Tyurin Daniil A. , Feldman Vladimir I.
Published: March 2021

A hydrogen-bonded CHF⋯HF complex was characterized by FTIR matrix isolation spectroscopy and ab initio calculations. Three possible structures of this complex were found at the coupled-cluster with single, double, and perturbative triple excitations [CCSD(T)/L3a_3] level of theory. The comparison between the experiment and theory reveals that the most stable structure with the binding energy of 6.48 kcal/mol is formed upon x-ray irradiation of isolated CH2F2 molecules in noble gas matrices (Ne, Ar, Xe). This species appears to be the first known intermolecular complex of monofluorocarbene, and its identification was unambiguously proved by IR absorptions corresponding to HF deformation (libration), CF stretching, H–C–F bending, and CH and HF stretching modes. It is worth noting that the corresponding spectral features in an argon matrix were previously tentatively ascribed to CH2F2+· and HF⋯CHF−· [L. Andrews and F. T. Prochaska, J. Chem. Phys. 70, 4714 (1979)], but the calculations performed in the present study definitely support the re-assignment. The observed CHF⋯HF complex can be converted to the parent CH2F2 under the action of light with λ < 525 nm. The plausible mechanism of this conversion using the conical intersection concept is discussed.
Resonators made of a disk and a movable continuous-membrane
Authors: Abudi Tom Lenkiewicz , Douvidzon Mark , Bathish Baheej , Carmon Tal
Published: March 2021

Microcavities are used for resonantly enhanced interactions of light with matter or particles. Usually, the resonator’s sensitivity drops down with every particle attached to its interface due to the inherent scattering losses and the corresponding degradation of the optical quality factor. Here, we demonstrate, for the first time, a hybrid resonator made of a dielectric disk and a continuous membrane. The membrane is evanescently coupled to the disk while both membrane and disk are mechanically separated. Therefore, the optical mode is co-hosted by the disk and the membrane, while we use a nanopositioning system to control the disk motion. We experimentally demonstrate that spreading scatterers on the membrane and then moving the membrane parallel to the disk brings different scatterers into and out of the optical-mode region. We also show that the membrane’s motion toward the disk results in a 35 GHz drift in the optical resonance frequency. The membrane is continuous in two dimensions and can move a practically unlimited distance in these directions. Furthermore, the membrane can move from a state where it touches the disk to an unlimited distance from the disk. Our continuum-coupled resonator might impact sustainable sensors where the perpetual motion of analytes into and out of the optical-mode region is needed. Additionally, the membrane can carry quantum dots or point defects such as nitrogen-vacancy centers to overlap with the optical mode in a controllable manner. As for non-parallel motion, the membrane’s flexibility and its ability to drift resonance frequency might help in detecting weak forces.
Single-trap emission kinetics of vertical β-Ga2O3 Schottky diodes by deep-level transient spectroscopy
Authors: Chen Jiaxiang , Luo Haoxun , Qu HaoLan , Zhu Min , Guo Haowen , Chen Baile , Lv Yuanjie , Lu Xing , Zou Xinbo
Published: March 2021

We report the emission kinetics of a single-electron trap (E1, E
C–0.63 eV) in Sn-doped (

2
ˉ

01) β-Ga2O3 crystals studied using deeplevel transient spectroscopy (DLTS). The time constant (

τ

) of the electrons emitted from the trap level E1 was thoroughly investigated as a function of the temperature and the electric field (E-field) . The temperature-dependence

τ

of E1 was extracted by both the temperature-scanning and isothermal modes of DLTS. It was found that the emission process accelerated exponentially from 200 K to 350 K. The E-field dependence of the emission time constant could be divided into two regimes for all measurement steps (250–325 K). In the low-electric-field regime, the emission time constant of the trap decreased slightly with a strengthened E-field. With a further enhancement of the E-field (E > 1.76 MV cm−1), the field-enhanced emission rate was accurately modeled by the Poole–Frenkel effect; the accelerated emission process was attributed to a reduction of the Coulomb well barrier for the donor-like trap E1.
Cavity-enhanced magnetometer with a spinor Bose–Einstein condensate
Authors: Gietka Karol , Mivehvar Farokh , Busch Thomas
Published: March 2021

We propose a novel type of composite light–matter magnetometer based on a transversely driven multi-component Bose–Einstein condensate coupled to two distinct electromagnetic modes of a linear cavity. Above the critical pump strength, the change of the population imbalance of the condensate caused by an external magnetic field entails the change of relative photon number of the two cavity modes. Monitoring the cavity output fields thus allows for nondestructive measurement of the magnetic field in real time and we show that the sensitivity of the proposed magnetometer exhibits Heisenberg-like scaling with respect to the atom number. For state-of-the-art experimental parameters, we calculate the lower bound on the sensitivity of such a system to be of the order of fT

(

H
z

)

−
1

–pT

(

H
z

)

−
1

for a condensate of 104 atoms with coherence times on the order of several ms.
Predicting disease severity in children with combined attention deficit hyperactivity disorder using quantitative features from structural MRI of amygdaloid and hippocampal subfields
Authors: Song Shanghu , Qiu Jianfeng , Lu Weizhao
Published: March 2021

Objective. Volumetric changes in the amygdaloid and hippocampal subfields have been observed in children with combined attention deficit hyperactivity disorder (ADHD-C). The purpose of this study was to investigate whether volumetric changes in the amygdaloid and hippocampal subfields could be used to predict disease severity in children with ADHD-C. Approach. The data used in this study was from ADHD-200 datasets, a total of 76 ADHD-C patients were included in this study. T1 structural MRI data were used and 64 structural features from the amygdala and hippocampus were extracted. Three ADHD rating scales were used as indicators of ADHD severity. Sequential backward elimination (SBE) algorithm was used for feature selection. A linear support vector regression (SVR) was configured to predict disease severity in children with ADHD-C. Main results. The three ADHD rating scales could be accurately predicted with the use of SBE-SVR. SBE-SVR achieved the highest accuracy in predicting ADHD index with a correlation of 0.7164 (p < 0.001, tested with 1000-time permutation test). Mean squared error of the SVR was 43.6868, normalized mean squared error was 0.0086, mean absolute error was 3.2893. Several amygdaloid and hippocampal subregions were significantly related to ADHD severity, as revealed by the absolute weight from the SVR model. Significance. The proposed SBE-SVR could accurately predict the severity of patients with ADHD-C based on quantitative features extracted from the amygdaloid and hippocampal structures. The results also demonstrated that the two subcortical nuclei could be used as potential biomarkers in the progression and evaluation of ADHD.
Influence of magnesium and strontium substitutions in the structure of hydroxyapatite lattice on the deposition rate and properties of the CaP coatings formed via RF-sputtering of the powder targets
Authors: Fedotkin A Y , Kozelskaya A I , Korotchenko N M , Gigilev A S , Shesterikov E V , Tverdokhlebov S I
Published: March 2021

This work is dedicated to studying of the properties of the calcium phosphate (CaP) coatings deposited on Ti substrates by radio-frequency magnetron sputtering (RFMS) of three hydroxyapatite-based powder targets: pure hydroxyapatite (HA), Mg-substituted HA (Mg-HA, Mg = 0.93 ± 0.13 at.%) and Sr-substituted HA (Sr-HA, Sr ∼ 0.47 at.%). The influence of ionic substitutions in the structure of the sputtered targets on the surface morphology, physicochemical properties of the coatings and their wettability were studied. It is revealed that Mg and Sr ionic substitutions in the crystal lattice of HA at these concentrations don’t affect deposition rate, however, it influences morphology, wettability and elemental and phase composition of deposited coatings.
Immobilization of radioactive vacuum oil into open-porous glass-carbonic material
Authors: Kazakovsky N T , Korolev V A , Yu Vozleeva A
Published: March 2021

The paper discusses issues of ensuring safe operation of vacuum facilities in handling radioactive materials. A shaping material for effective immobilization of compound with consolidated organic radioactive waste is proposed.
Regularities of structure and properties modification of the steel surface layer as a result of high-cycle high-speed melting of the “film (Si + Nb) / (steel) substrate” system by an intense pulsed electron beam
Authors: Koval N N , Ivanov Yu F , Shugurov V V , Teresov A D , Petrikova E A , Rygina M E
Published: March 2021

Surface alloying is a promising method for improving the service characteristics of machine parts and mechanisms. The aim of this work is to analyze the patterns of evolution of the elemental and phase composition, the state of the defect substructure of the surface layer of carbon steel subjected to multi-cycle treatment (the number of cycles was varied from 1 to 5), which combines the formation of a film / substrate system and irradiation with an intense pulsed electron beam. Silicon and niobium are used as alloying elements. It has been established that irradiation of the system “film (Si + Nb) / (steel 5135) substrate” at an electron beam energy density of 20 J / cm2 leads to the formation of a multiphase high-speed cellular crystallization structure in the surface layer. The size of the crystallization cells varies from 180 nm to 520 nm, reaching the maximum size after 3 cycles of deposition-irradiation. The surface layer of steel is quenched during processing to form a martensitic structure. It was found that the Nb5Si3 is the hardening phase of the modified layer, the maximum amount of what (up to 9 wt%) was revealed after three processing cycles. It is shown that the maximum hardness of the surface layer of modified steel 5135, equal to 9300 MPa (3.2 times higher than the hardness of steel 5135 in the initial state), is achieved after 3 cycles of deposition / irradiation. The wear resistance of steel at this processing mode increases more than 90 times. It has been suggested that the hardening of steel surface layer is due to the formation of a quenched structure and the release of niobium silicide particles.
Metallic (CoFe)/Cu superlattices with record microwave giant magnetoresistive effect
Authors: Rinkevich A B , Milyaev M A
Published: March 2021

Technology of preparation of (CoFe)/Cu superlattices by magnetron sputtering is discussed. The parameters of growth have been obtained which allows to get superlattices with very high magnetoresistance. Methods of characterization of superlattices are described. Microwave magnetoresistance in millimeter waveband is measured by transmission method. The record value of microwave magnetoresistance exceeding 80% is obtained.
Structure and peculiarities of boundary friction of ta-C coatings obtained by pulse-plasma deposition
Authors: Samusenko V D , Zavidovskii I A , Streletskii O A , Buyanovskii I A , Khrushchov M M , Petrzhik M I , Shcherbakov Yu I
Published: March 2021

The results of an investigation of thin ta-C coatings obtained by the method of pulse-plasma deposition concerning the peculiarities of their structural state and tribological behavior in boundary lubrication conditions have been presented.
Thin-film bioinert vacuum ion-plasma coatings for medical implants
Authors: Shekhtman S R , Suhova N A , Migranov M Sh
Published: March 2021

The article discusses bioinert coatings used to protect the surface of implants from aggressive effects. Studies on adhesive strength, corrosion and wear resistance are presented, showing that the nanostructured coating obtained by the developed technology has enhanced performance properties. The studies were conducted using modern techniques for assessing the properties of coated materials. The main stages of the technology of vacuum ion-plasma deposition of coatings are described.
Thermal insulators based on abundant waste materials
Authors: Alhabeeb B A , Mohammed H N , Alhabeeb S A
Published: March 2021

Any airconditioned zone must be thermally insulated from its surroundings to maintain the desired temperature. Thermal insulators thus play a significant role in reducing heat transfer between airconditioned areas and their surroundings to save energy. Thermal insulators are usually made from materials with low thermal conductivity, and to reduce the cost of such insulators, this study investigated the use of waste organic materials as thermal insulators. This study is the second part of a project that aims to achieve an optimised insulator from both the thermal and economic perspectives. To achieve this, the heat conductivity of five different samples made from hair, grass, date seed, and date palm fibre were examined. The all samples were made with industrial white glue as a binder. The heat flow method was employed to determine their thermal conductivity, with results that showed that all samples offered thermal resistance to heat transfer in the range 0.0530 to 0.1068 W/mK. The best thermal resistance was provided by the sample made from hair and fibres. The current study supports sustainability by encouraging the use of waste organic materials in thermal insulators.
Synthesis and Characterisation of Bioactive Glass 13-93 Scaffolds for Bone Tissue Regeneration
Authors: Mehatlaf Auday A , Farid Saad B H , Atiyah Alaa A
Published: March 2021

A modified sol-gel method was used in the current work to prepare a 13-93 bioactive glass powder, which was selected for the therapeutic actions of its constituent parts. In particular bioactive glass 13-93 can chemically bond with host tissue and induce osteogenesis. The produced gel was calcined at a temperature of 600 °C, while particle size analysis and x-ray diffraction were performed after the preparation of the glass powder. Porous bioactive glass 13-93 scaffolds were synthesised using the polymer foam replication technique that uses polyurethane sponges as a template. Sintering at 700 °C was then performed for one hour to the produce the required structures. After sintering, the microstructure was examined by scanning electron microscope (SEM) and Fourier transform infrared analysis (FTIR). The x-ray diffraction (XRD) results were also examined. The average particle size of bioactive glass 13-93 thus produced was about 2.978 μm, and XRD pattern analysis showed that the porous scaffolds were amorphous. The microstructure of the 13 – 93 glass scaffolds contained interconnected cellular pores and a dense network of bioactive glass, allowing scaffolds with porosity between 80 and 83% to be obtained. An in vitro bioactivity test was performed on the scaffolds by soaking them in a solution of simulated body fluid (SBF). The subsequent SEM images confirmed the bioactivity of the prepared scaffolds based on the formation of obvious and dense hydroxyapatite particles on the surface after 7 days of immersion in SBF. It was thus concluded that bioactive glass scaffold prepared in this work via the polymer foam replication technique has the potential to be used in several future applications.
Quantitative assessing of crystal field, nephelauxetic, and Stokes shift effects on the blue luminescence of Eu2+ ions incorporated in ZnS films
Authors: López-Lugo Victor Hugo , Rivera-Medina Martha Judith , Alonso-Huitrón Juan Carlos
Published: March 2021

A quantitative study of the crystal field, nephelauxetic, and Stokes shift effects on the 5d → 4 f levels of Eu2+ ions incorporated in ZnS films is presented. The magnitude of the crystal effect was calculated using the simplest point charge model to express the crystal field splitting of Eu2+ 5d orbitals surrounded by four S2− ligands in tetrahedral coordination symmetry. The shift of the centroid of the 5d levels by nephelauxetic effect was analyzed using a model that involves the polarizability of the anion ligands, similar to that used to investigate this effect for Ce3+ in many inorganic compounds. The Stokes shift was evaluated according to the Frank-Condon principle, under the idealized situation where the Stokes shift and the emission bandwidth can be expressed in terms of the Huang-Rhys parameter. We found that the redshift

ϵ

c
f
s

=
0.32

eV

of the 5d → 4 f transition for the free Eu2+ ion, due to crystal field splitting was half of the redshift due to the nephelauxetic effect. This result is consistent with the large size, large polarizability, and low electronegativity of the sulfide ions. We also found a relatively large Stokes shift which can be attributed to the autoionization of the 5d electrons to the conduction band levels. The total redshift of the 5d and 4 f energy levels with respect to the 5d and 4 f energy gap for a free Eu2+ in vacuum fits quite well with the blue luminescence peaked at 2.73 eV for Eu2+ ions incorporated in the ZnS films. Based on the experimental results and the calculations for the crystal field splitting, nephelauxetic, and Stokes shift effects, we also propose a simplified energy band and levels diagram which helps to explain the excitation-emission mechanisms of the blue luminescence of the Eu2+ ions incorporated in the ZnS films.
Study of double-chamber air arc plasma torch and the application in solid-waste disposal
Authors: CAO Yawen , LI Bin , HAN Xianwei , TAN Chang , ZHANG Zhihao , ZHANG Xizhe , WEI Jianguo
Published: March 2021

Arc plasma can be applied in hazardous solid waste disposal for higher temperature than common heating methods, but some practical issues exist in practical engineering application. In this study, an air arc plasma torch with double chambers and magnetic controlling is designed to realize wide variable power and long electrode life. The detailed characteristics and laws of the air arc are studied. The condition parameters of arc current (I), air flow rate (G) and the structure parameters of inlet area ratios and electrode diameters influence both the arc voltage and arc root positions. The arc rotating driven by magnetic field effectively lengthens the electrode life. The gasification process and product of organic wastes by air plasma are influenced largely by the waste compositions and the air flow rate. A furnace structure with more even atmosphere and longer residence time should be considered for better gasification. Oxygen-deficient environment is important to suppress NO
x
formation during the application of air plasma. Inorganic solid wastes can be melt by the air plasma and cooled down to form compact vitreous structures in which heavy metals can be locked and the leaching rates significantly decrease down.
Structure of polymer-capped gold nanorods binding to model phospholipid monolayers
Authors: Quan Peiyu , Bu Wei , Wang Liming , Chen Chunying , Wu Xiaochun , Heffern Charlie , Lee Ka Yee C. , Meron Mati , Lin Binhua
Published: March 2021

We report an experimental study of the structure of polymer-capped gold nanorods (AuNRs) binding to model phospholipid monolayers to elucidate the mechanism that drives the insertion of the AuNRs into phospholipid membranes. The experimental system consists of four different cases of AuNRs interacting with lipid monolayers: cationic and anionic polymer-capped AuNRs suspended in the pure water subphase of Langmuir monolayers of zwitterionic and anionic phospholipids, separately. Liquid surface x-ray reflectivity was used to measure in situ the structure of the lipids and AuNRs at the air-water interface with sub-nanometer resolution, yielding quantitatively the amount, orientation, as well as depth of AuNR insertion into the monolayer. In the case of a zwitterionic monolayer composed of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine, cationic Poly-diallyldimethylammonium chloride (PDC) capped AuNRs (PDC-AuNRs) adsorbed peripherally at the water-lipid interface whereas the anionic Poly-sodium 4-styrenesulfonate (PSS) capped AuNRs (PSS-AuNRs) penetrated deeply into the lipid monolayer. In the case of an anionic monolayer composed of 1-stearoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (SOPG), PDC-AuNRs inserted into the monolayer whereas PSS-AuNRs were not even attracted to the monolayer. The results suggest that the adsorption process of AuNRs to model membranes may proceed through different mechanisms. In the presence of a charged membrane, electrostatic interactions drove the AuNRs to or away from the membrane depending on the nature of the charge of the lipid film and the AuNRs, while in the presence of a zwitterionic membrane, both electrostatic interactions and hydrophobic interactions mediated the insertion of the AuNRs into the membrane.
Exciton effects in perovskite nanocrystals
Authors: Ahumada-Lazo Ruben , Saran Rinku , Woolland Oliver , Jia Yunpeng , Kyriazi Maria-Eleni , Kanaras Antonios G , Binks David , Curry Richard J
Published: March 2021

Nanocrystals (NCs) of perovskite materials have recently attracted great research interest because of their outstanding properties for optoelectronic applications, as evidenced by the increasing number of publications on laboratory scale devices. However, in order to achieve the commercial realisation of these devices, an in-depth understanding of the charge dynamics and photo-physics in these novel materials is required. These dynamics are affected by material composition but also by their size and morphology due to quantum confinement effects. Advances in synthesis methods have allowed nanostructures to be produced with enhanced confinement and structural stability, enhancing the efficiency of energy funnelling and radiative recombination and so resulting in more efficient light emitting devices. In addition, photovoltaics could greatly benefit from the exploitation of these materials not only through their deployment in tandem cell architectures but from the use of multiple exciton generation in these NCs. These systems also offer the opportunity to study quantum effects relating to interactions of excited states within and between NCs. Properties and behaviour that includes an enhanced Rashba effect, superfluorescence, polariton lasing, Rydberg exciton polariton condensates, and antibunched single photon emission have been observed in a single metal halide perovskite NC. The further study of these in NC systems will shed new light on the fundamental nature of their excited states, their control and exploitation. In this perspective, we give an overview of these effects and provide an outlook for the future of perovskite NCs and their devices.
High-energy noise-like pulses generated by an erbium-doped fiber laser incorporating a PbS quantum-dot polystyrene composite film
Authors: Zhao Wei , Huang Qianqian , Li Kai , Gao Chenyu , Cheng Xi , Yan Yuyang , Guo Qiang , Sun Xiaolan , Mou Chengbo
Published: March 2021

We demonstrate a high-energy noise-like pulse (NLP) generated by an Er-doped fiber (EDF) laser incorporating a PbS quantum dot (QD) polystyrene (PS) composite film as a saturable absorber (SA). Benefitting from the intrinsic properties of NLPs and the high damage threshold of the PbS QD PS composite film, a stable NLP train can be obtained with an output power of 96.3 mW at a pump power of 660 mW, corresponding to a pulse energy of 9.68 nJ. This represents the highest pulse energy ever reported in an NLP EDF laser incorporating material-based SAs. The slope efficiency reached 17.37% and the steady NLP operation was able to be maintained for several hours under laboratory conditions. Our experimental results prove that the PbS QD PS composite film can serve as an effective SA to realize high-energy pulses in a mode-locked fiber laser.
Posture and Muscle Activity during Waste Collection Work
Authors: Netto Kevin , Francis-Pester Garry , Lewis Caleb , Dunnill Patrina , Darling Russell
Published: March 2021

The musculoskeletal load in waste collection has been examined through simulated assessment of pulling and pushing bins as well as lifting and throwing rubbish bags. With the onset of mechanization, many of these tasks do not exist and workers are faced with other loads not previously assessed. The purpose of this study was to quantify the postures and muscle activity during mechanized waste collection work. Three subtasks of mechanized waste collection were identified, namely driving, bin collection, and egress and access of the vehicle. Spinal, shoulder, and upper limb kinematics along with surface electromyography from three muscles were collected during these tasks in a typical work shift. During driving and bin collection, participants adopted a head-extended, torso forward-flexed posture with frequent rotations of the head and neck. Egress and access of the vehicle produced substantially larger ranges of movement compared with driving and bin collection. The forward-flex, sitting posture can increase the risk of low back pain if there are undulations in the terrain and if this posture is adopted for prolonged periods. The frequent head and neck rotations can increase the incidence and severity of neck pain. Prolonged driving has been linked with an increased cardiometabolic risk and egress and access has increased risk of trips and falls from a height. Managers of waste collection workers should consider implementing interventions to reduce the exposure of this important workforce to the deleterious demands of their work.
Update on Third Party Observers in Neuropsychological Evaluation: An Interorganizational Position Paper
Authors: Glen Tannahill , Barisa Mark , Ready Rebecca , Peck Edward , Spencer Tresa Roebuck
Published: March 2021

Objective

The National Academy of Neuropsychology (NAN), the American Academy of Clinical Neuropsychology (AACN), and the American College of Professional Neuropsychology (ACPN) collaborated to publish an update to their original position statements, confirming the organizations' opposition to third party observer (TPO).

Method

A review of literature addressing TPO effects, ethical standards, professional organization position statements, test publisher policies and new telemedicine developments was completed to obtain consensus on relevant issues in TPO and recording of neuropsychological evaluations.

Results

TPO has been shown to impact the cognitive functions most often assessed in forensic or medicolegal settings. Third party observation, whether in person, recorded or electronic, remains a potential threat to the validity and reliability of evaluation results, and violates test security guidelines, ethical principles and standards of conduct in the field. Demands for TPO in the context of medicolegal or forensic settings have become a tactic designed to limit the ability of the consulting neuropsychologist to perform assessment and provide information to the trier of fact.

Conclusion

The field of neuropsychology opposes the presence of TPO in the setting of medicolegal or forensic neuropsychological evaluations.
A Modified Approach to Transconjunctival Levator Advancement Offering Intraoperative Options
Authors: Deng Zhizhong , Zhou Xianyu , Lu Lin , Jin Rui , Qiu Yucheng , Yang Jun , Liu Fei
Published: March 2021

Background

The transconjunctival technique is an effective approach to mild to moderate blepharoptosis repair that does not involve skin incision. However, accurate surgical manipulation of this method is greatly restricted by poor intraoperative evaluation.

Objectives

The aim of this study was to introduce a modified transconjunctival approach with flexible intraoperative adjustments in order to achieve more accurate ptosis correction.

Methods

Taking a transconjunctival approach, the levator aponeurosis and Müller’s muscle were folded with a square-like mattress suture for flexible adjustment and accurate correction.

Results

In 18 mild ptosis eyelids, 94.5% (17 eyelids) achieved adequate or normal correction. In 9 eyelids with moderate ptosis, 88.9% (8 eyelids) achieved adequate or normal correction. Of 24 ptosis patients, 23 (95.8%) achieved a good or fair symmetry result.

Conclusions

This study presents a modified transconjunctival technique for repair of mild to moderate ptosis, which is characterized by flexible intraoperative adjustments that produce satisfying functional and aesthetic outcomes.

Level of Evidence: 4
How Does Wearing a Facecover Influence the Eye Movement Pattern in Times of COVID-19?
Authors: Frank Konstantin , Schuster Luca , Alfertshofer Michael , Baumbach Sebastian Felix , Herterich Viktoria , Giunta Riccardo E , Moellhoff Nicholas , Braig David , Ehrl Denis , Cotofana Sebastian
Published: March 2021

Background

Since the emergence of the COVID-19 pandemic facecovers have become a common sight. The effect of facecovers on the gaze when looking at faces has not yet been assessed.

Objectives

The aim of the present study was to investigate any potential differences in eye movement pattern in observers exposed to images showing a face without and with a facecover to identify if there is truly a change of gaze when identifying (masked) facial features.

Methods

The eye movement of 64 study participants (28 males and 36 females) with a mean [standard deviation] age of 31.84 [9.0] years was analyzed in this cross-sectional observational study. Eye movement analysis was conducted based on positional changes of eye features within an x- and y-coordinate system while two images (face without/with facecover) were displayed for 8 seconds.

Results

The results of this study revealed that the sequence of focusing on facial regions was not altered when wearing a facecover and followed the sequence: perioral, nose, periorbital. Wearing a facecover significantly increased the time spent focusing on the periorbital region and also increased the number of repeated eye fixations during the 8-second visual stimulus presentation. No statistically significant differences were observed between male and female participants in their eye movement pattern across all investigated variables (P > 0.433).

Conclusions

The altered eye movement pattern caused by wearing facecoverings that this study has revealed suggests that, during the COVID-19 pandemic, aesthetic practitioners might consider developing marketing and treatment strategies that principally target the periorbital area.
PRISM: recovering cell-type-specific expression profiles from individual composite RNA-seq samples
Authors: Häkkinen Antti , Zhang Kaiyang , Alkodsi Amjad , Andersson Noora , Erkan Erdogan Pekcan , Dai Jun , Kaipio Katja , Lamminen Tarja , Mansuri Naziha , Huhtinen Kaisa , Vähärautio Anna , Carpén Olli , Hynninen Johanna , Hietanen Sakari , Lehtonen Rainer , Hautaniemi Sampsa
Published: March 2021

Motivation

A major challenge in analyzing cancer patient transcriptomes is that the tumors are inherently heterogeneous and evolving. We analyzed 214 bulk RNA samples of a longitudinal, prospective ovarian cancer cohort and found that the sample composition changes systematically due to chemotherapy and between the anatomical sites, preventing direct comparison of treatment-naive and treated samples.

Results

To overcome this, we developed PRISM, a latent statistical framework to simultaneously extract the sample composition and cell-type-specific whole-transcriptome profiles adapted to each individual sample. Our results indicate that the PRISM-derived composition-free transcriptomic profiles and signatures derived from them predict the patient response better than the composite raw bulk data. We validated our findings in independent ovarian cancer and melanoma cohorts, and verified that PRISM accurately estimates the composition and cell-type-specific expression through whole-genome sequencing and RNA in situ hybridization experiments.

Availabilityand implementation

https://bitbucket.org/anthakki/prism.

Supplementary information

Supplementary data are available at Bioinformatics online.
Hacking for good: Leveraging HackerOne data to develop an economic model of Bug Bounties
Authors: Sridhar Kiran , Ng Ming
Published: March 2021

We ran a study of bug bounties, programs where gig economy security researchers are compensated for pinpointing and explaining vulnerabilities in company code bases. Bug bounty advocates have argued that they are a cost-effective means for companies of all types to shore up their security posture. Our research—which analyzes a large, proprietary dataset and which leverages instrumental variables to eliminate potential sources of endogeneity—provides empirical support for this assertion. Security researchers have a price elasticity of supply of between 0.1 and 0.2 at the median, indicating that they are largely motivated by non-pecuniary factors; a company is still able to derive utility from bug bounties even if they have a limited ability to pay security researchers. Moreover, a company’s revenue and brand profile do not have an economically significant impact on the number of valid security vulnerabilities reports its program receives. However, we found that companies in the finance, retail, and healthcare sectors are notified of fewer valid vulnerabilities, ceteris paribus, than companies in other sectors, though these estimates are not statistically significant at the 5% level. We also found no evidence that new companies joining the HackerOne platform dampen the number of reports that firms receive. Finally, we find that programs receive fewer valid reports as they grow older and bugs become harder to find. This negative age effect may be dampened if the program increases the code base available for hacking.
Restraint under conditions of uncertainty: Why the United States tolerates cyberattacks
Authors: Kaminska Monica
Published: March 2021

The United States struggles to impose meaningful costs for destructive or disruptive cyber operations. This article argues that the United States' restrained responses stem from a desire to avoid risk in an inherently uncertain operational environment. The societal desire for risk avoidance is the prism through which policymakers address the cyber domain and deliberate responses to attacks. The article shows that two particular operational characteristics of cyberspace—its complex adaptiveness and the ease of proliferation—combine to increase the risk of misattribution and the risk of unintended effects, including collateral damage, inadvertent escalation and blowback. These characteristics present a particular obstacle for risk societies such as the United States in the application of meaningful punishments. In addition to establishing the roots of US restraint, the article traces the application of risk management practices, including preventive action, increasing resilience and consequence management, from the Obama administration to the Trump administration. The analysis reveals that risk management has underpinned the overall US approach to the cyber domain.
The Effects of Vegetation Type on Oedaleus decorus asiaticus (Orthoptera: Acrididae) Oviposition and Hatching Success
Authors: Li Hongmei , Zhang Yan , Wang Guangjun , Lowry Alyssa , Huang Wenjiang , Dong Yingying , Shang Suqin , Luke Belinda
Published: March 2021

Oedaleus decorus asiaticus (Bei-Bienko, 1941) has been regarded as one of the most dominant locusts in the northern grassland, the adjacent area of agriculture and animal farmland, in China. The aims of this study were to investigate the effects of vegetation type on the oviposition behavior of this pest in an open field and the hatching success of the offspring in the following year. The results showed that vegetation type did have a significant effect on whether any egg pods were laid by O. d. asiaticus. Once the females laid eggs, vegetation type and cage number had a significant effect on the number of egg pods laid. The highest number of egg pods was found in the Cleistogenes squarrosa treatment, followed by Stipa krylovii and then Leymus chinensis, while the Artemisia frigida treatment contained the lowest number of egg pods. The O. d. asiaticus eggs laid in S. krylovii and C. squarrosa treatments had a significantly higher hatching success rate (over 53%) than the other two grasses (below 40%). In short, habitats with C. squarrosa and S. krylovii grasses are likely to be preferred by ovipositing females, thus population monitoring efforts of O. d. asiaticus should focus on these habitats.
Outbreak of SARS-CoV-2: challenge for diagnosis and medical management in patients with left ventricular assist device: a case series
Authors: Dan Pan , Birgit Frotscher , Matei Mathieu , Vuillemin Veronique , Ottenin Helene , Maureira Pablo-Juan , Vanhuyse Fabrice
Published: March 2021

Background

The outbreak of coronavirus disease 2019 (COVID-19) exposes vulnerable patients to high risk of mortality. Patients with left ventricular assist device (LVAD) usually have symptoms such as cough, fever, and shortness of breath because of their cardiac condition and comorbidity, therefore these related symptoms challenge the correct diagnosis in time within the COVID-19 pandemic.

Case summary

We report two case studies of patients with LVAD in whom COVID-19 related symptoms were overlapped by their cardiac status and comorbidities. In the first case, the patient was admitted for suspicion of COVID-19 due to cough and shortness of breath for 1 month. The blood test evocated a high index of suspicion of COVID-19. The nasopharyngeal test for COVID-19 performed on admission and at Day 2 was inconclusive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but the test obtained on Day 3 of admission was positive, whereas computed tomography confirmed the diagnosis of COVID-19. This patient developed acute respiratory distress syndrome (ARDS) and nasal epistaxis within 48 h during hospitalization. The ARDS was treated by non-invasive ventilation and probabilistic antibiotics for 3 days and resulted significant improvement. The nasal epistaxis due to international normalized ratio increase was treated by nasal packing and vitamin K antagonist was switched to parenteral heparin infusion. The patient was kept hospitalized for 1 month for further supportive treatment. In the second case, the patient was admitted for recurrent anaemia due to melaena, the patient was tested for COVID-19 because of new-onset symptoms of cough and rhinorrhoea. The first nasopharyngeal test was positive, and sudden increase of anticoagulation status was noted in the setting of gastrointestinal bleeding. The anticoagulation status was controlled by parenteral heparin infusion, and the melaena was disappeared at Day 3. The moderate dyspnoea of the patient was quickly improved with nasal oxygen delivery for 4 days. The patient was discharged at Day 5.

Discussion

COVID-19 specific symptoms are challenging to distinguish in patients with LVADs, although radiological evidence can be beneficial in the COVID-19 diagnosis. We also observed the need for precise anticoagulation control to avoid bleeding or thrombotic events in these patients.
Diagnostic approach to a cardiac mass: a case report of misdiagnosed cardiac synovial sarcoma
Authors: Ouarrak Safia , El Ouali Zakaria , Elkebir Asmaa , Moumna Kawthar , Karkouri Mehdi , Azzouzi Leila , Habbal Rachida
Published: March 2021

Background

Cardiac synovial sarcoma (CSS) is an extremely rare malignant tumour with a poor prognosis. We report the case of a 31-year-old woman who presented with a CSS in the right atrium and was initially misdiagnosed with a tuberculoma. The aim of this article is to focus on the importance of having broad differential diagnoses including rare entities.

Case summary

A 31-year-old White woman, with a close contact with a relative having pulmonary tuberculosis, presented to the emergency unit with severe dyspnoea. Chest radiography and echocardiography showed a large pericardial effusion with a mass in the right atrium. Pericardiocentesis removed bloody exudative fluid with adenosine desaminase at 17 UI/L and no malignant cells in the cytological study. Cardiac magnetic resonance revealed a tuberculoma of the right atrium. Intraoperatively, the mass was only biopsied because of the local invasion. Histological study concluded to a CSS. The patient died 3 days later.

Discussion

This case highlights the importance of having broad differential diagnoses including rare entities. Histology was the key investigation for the diagnosis of CSS which has no clinical nor laboratory or imaging pathognomonic signs.
Risk analysis for early mortality in emergency acute type A aortic dissection surgery: experience of Tokyo Acute Aortic Super-network
Authors: Yamasaki Manabu , Yoshino Hideaki , Kunihara Takashi , Akutsu Koichi , Shimokawa Tomoki , Ogino Hitoshi , Kawata Mitsuhiro , Takahashi Toshiyuki , Usui Michio , Watanabe Kazuhiro , Masuhara Hiroshi , Yamamoto Takeshi , Nagao Ken , Takayama Morimasa
Published: March 2021

OBJECTIVES

We investigated the various pre- and postoperative complications related to early (30-day) mortality after open surgery for acute type A aortic dissection.

METHODS

Data from the Tokyo Acute Aortic Super-network database spanning January 2015 to December 2017 were retrospectively reviewed. Pre- and postoperative factors related to early postoperative mortality were assessed in 1504 of 2058 (73.0%) consecutive patients [age: 66.6 (SD: 13.5) years, male: 52.9%] who underwent acute type A aortic dissection repair.

RESULTS

The early mortality rate following surgical repair was 8.9%. According to multivariable analysis, male sex [odds ratio (OR) 1.670, 95% confidence interval (CI) 1.063–2.624, P = 0.026], use of percutaneous circulatory assist devices (n = 116, 7.7%) including extracorporeal membrane oxygenators or intra-aortic balloon pumps (OR 4.857, 95% CI 2.867–8.228, P < 0.001), shock (n = 162, 10.8%) (OR 3.06, 95% CI 1.741–5.387, P < 0.001), cardiopulmonary arrest (n = 41, 2.7%) (OR 7.534, 95% CI 3.407–16.661, P < 0.001), coronary ischaemia (n = 36, 2.3%) (OR 2.583, 95% CI 1.042–6.404, P = 0.041) and cerebral ischaemia (n = 59, 3.9%) (OR 2.904, 95% CI 1.347–6.261, P = 0.007) were independent preoperative risk factors for early mortality, while cardiac tamponade (n = 34, 2.3%) (OR 10.282, 95% CI 4.640–22.785, P < 0.001), cerebral ischaemia (n = 80, 5.3%) (OR 2.409, 95% CI 1.179–4.923, P = 0.016) and mesenteric ischaemia (n = 15, 1.0%) (OR 44.763, 95% CI 13.027–153.808, P < 0.001) were independent postoperative risk factors.

CONCLUSIONS

Not only critical preoperative conditions but also postoperative cardiac tamponade and vital organ ischaemia are risk factors for early mortality after acute type A aortic dissection repair.
Drosophila MOV10 regulates the termination of midgut regeneration
Authors: Takemura Masahiko , Bowden Nanako , Lu Yi-Si , Nakato Eriko , O’Connor Michael B , Nakato Hiroshi
Published: March 2021

The molecular mechanisms by which stem cell proliferation is precisely controlled during the course of regeneration are poorly understood. Namely, how a damaged tissue senses when to terminate the regeneration process, inactivates stem cell mitotic activity, and organizes ECM integrity remain fundamental unanswered questions. The Drosophila midgut intestinal stem cell (ISC) offers an excellent model system to study the molecular basis for stem cell inactivation. Here, we show that a novel gene, CG6967 or dMOV10, is induced at the termination stage of midgut regeneration, and shows an inhibitory effect on ISC proliferation. dMOV10 encodes a putative component of the microRNA (miRNA) gene silencing complex (miRISC). Our data, along with previous studies on the mammalian MOV10, suggest that dMOV10 is not a core member of miRISC, but modulates miRISC activity as an additional component. Further analyses identified direct target mRNAs of dMOV10-containing miRISC, including Daughter against Dpp (Dad), a known inhibitor of BMP/TGF-β signaling. We show that RNAi knockdown of Dad significantly impaired ISC division during regeneration. We also identified six miRNAs that are induced at the termination stage and their potential target transcripts. One of these miRNAs, mir-1, is required for proper termination of ISC division at the end of regeneration. We propose that miRNA-mediated gene regulation contributes to the precise control of Drosophila midgut regeneration.
Bayesian modeling of skewed X inactivation in genetically diverse mice identifies a novel Xce allele associated with copy number changes
Authors: Sun Kathie Y , Oreper Daniel , Schoenrock Sarah A , McMullan Rachel , Giusti-Rodríguez Paola , Zhabotynsky Vasyl , Miller Darla R , Tarantino Lisa M , Pardo-Manuel de Villena Fernando , Valdar William
Published: March 2021

Female mammals are functional mosaics of their parental X-linked gene expression due to X chromosome inactivation (XCI). This process inactivates one copy of the X chromosome in each cell during embryogenesis and that state is maintained clonally through mitosis. In mice, the choice of which parental X chromosome remains active is determined by the X chromosome controlling element (Xce), which has been mapped to a 176-kb candidate interval. A series of functional Xce alleles has been characterized or inferred for classical inbred strains based on biased, or skewed, inactivation of the parental X chromosomes in crosses between strains. To further explore the function structure basis and location of the Xce, we measured allele-specific expression of X-linked genes in a large population of F1 females generated from Collaborative Cross (CC) strains. Using published sequence data and applying a Bayesian “Pólya urn” model of XCI skew, we report two major findings. First, inter-individual variability in XCI suggests mouse epiblasts contain on average 20–30 cells contributing to brain. Second, CC founder strain NOD/ShiLtJ has a novel and unique functional allele, Xceg, that is the weakest in the Xce allelic series. Despite phylogenetic analysis confirming that NOD/ShiLtJ carries a haplotype almost identical to the well-characterized C57BL/6J (Xceb), we observed unexpected patterns of XCI skewing in females carrying the NOD/ShiLtJ haplotype within the Xce. Copy number variation is common at the Xce locus and we conclude that the observed allelic series is a product of independent and recurring duplications shared between weak Xce alleles.