bluuebunny/crossref_metadata_2025 huggingface dataset:
New Frontiers of Body Composition in Sport
Authors: Lukaski Henry , Raymond-Pope Christiana J.
Published: February 2021

The body composition phenotype of an athlete displays the complex interaction among genotype, physiological and metabolic demands of a sport, diet, and physical training. Observational studies dominate the literature and describe the sport-specific physique characteristics (size, shape, and composition) of adult athletes by gender and levels of competition. Limited data reveal how body composition measurements can benefit an athlete. Thus, the objective is to identify purposeful measurements of body composition, notably fat and lean muscle masses, and determine their impact on the health and performance of athletes. Areas of interest include relationships among total and regional body composition measurements, muscle function, sport-specific performance, risk of injury, return to sport after injury, and identification of activity-induced fluid shifts. Discussion includes the application of specific uses of dual X-ray absorptiometry and bioelectrical impedance including an emphasis on the need to minimize measurement errors and standardize protocols, and highlights opportunities for future research. This focus on functional body composition can benefit the health and optimize the performance of an athlete.
Primary Lymphoma of Internal Acoustic Meatus Mimicking Vestibular Schwannoma—A Rare Diagnostic Dilemma
Authors: Jayashankar Narayan , Kodur Swati , Patkar Deepak , Verma Mitusha
Published: February 2021

Background/Setting A subject presenting with a unilateral sensorineural hearing loss and with vertigo/imbalance and a lesion of internal acoustic meatus (IAM) most often represents a vestibular schwannoma. Several alternative pathologies involving the region, with clinical and neuroradiological similarities, could lead to an error in judgement and management. Rare tumors of the IAM pose unique diagnostic difficulty. A rare case that we present here had a typical history and imaging findings suggestive of vestibular schwannoma. A primary central nervous system (CNS) lymphoma was diagnosed in later stages of brain involvement warranting a retrospective analysis of the entity.

Case Summary An 80-year-old male presented with unilateral sensorineural hearing loss, vertigo, and imbalance. On imaging, he was found to have a lesion in the left internal auditory meatus, reported as a vestibular schwannoma and operated upon. Subject's condition worsened with time and a repeat imaging was suggestive of a CNS lymphoma with lesions involving bilateral cerebellum and subcortical white matrix.

Conclusion To conclude, primary CNS lymphoma presenting an isolated lesion in the IAM with no other parenchymal lesions at presentation is a rare incidence; to our knowledge this is the first case of such unique presentation.
Implementation of a Physician-Based Stroke Unit in a Remote Hospital of North-East India-Tezpur Model
Authors: John Lydia , William Akanksha , Dawar Dimple , Khatter Himani , Singh Pratibha , Andrias Anjana , Mochahari Christina , Langhorne Peter , Pandian Jeyaraj
Published: February 2021

Objective The study aims to determine the effects of implementing stroke unit (SU) care in a remote hospital in North-East India.

Materials and Methods This before-and-after implementation study was performed at the Baptist Christian Mission Hospital, Tezpur, Assam between January 2015 and December 2017. Before the implementation of stroke unit care (pre-SU), we collected information on usual stroke care and 1-month outcome of 125 consecutive stroke admissions. Staff was then trained in the delivery of SU care for 1 month, and the same information was collected in a second (post-SU) cohort of 125 patients.

Statistical Analysis Chi-square and Mann–Whitney U test were used to compare group differences. The loss to follow-up was imputed by using multiple imputations using the Markov Chain Monto Carlo method. The sensitivity analysis was also performed by using propensity score matching of the groups for baseline stroke severity (National Institute of Health Stroke Scale) using the nearest neighbor approach to control for confounding, and missing values were imputed by using multiple imputations. The adjusted odds ratio was calculated in univariate and multivariate regression analysis after adjusting for baseline variables. All the analysis was done by using SPSS, version 21.0., IBM Corp and R version 4.0.0., Armonk, New York, United States.

Results The pre-SU and post-SU groups were age and gender matched. The post-SU group showed higher rates of swallow assessment (36.8 vs. 0%, p < 0.001), mobility assessment, and re-education (100 vs. 91.5%, p = 0.037). The post-SU group also showed reduced complications (28 vs. 45%, p = 0.006) and a shorter length of hospital stay (4 ± 2.16 vs. 5 ± 2.68 days, p = 0.026). The functional outcome (modified ranking scale) at 1-month showed no difference between the groups, good outcome in post-SU (39.6%) versus pre-SU (35.7%), p = 0.552.

Conclusion The implementation of this physician-based SU care model in a remote hospital in India shows improvements in quality measures, complications, and possibly patient outcomes.
Complicated Acute Appendicitis during COVID-19 Pandemic: The Hidden Epidemic in Children
Authors: Delgado-Miguel Carlos , Muñoz-Serrano Antonio J. , Miguel-Ferrero Miriam , De Ceano-Vivas María , Calvo Cristina , Martínez Leopoldo
Published: February 2021

Introduction Since home confinement for novel coronavirus disease 2019 (COVID-19) pandemic began, pediatric visits to the emergency department (ED) have decreased, including consultation for abdominal pain. Our aim is to investigate the incidence of complicated acute appendicitis (AA; peritonitis or appendicular mass) during confinement for COVID-19 pandemic and to compare it with the previous 5 years.

Materials and Methods A retrospective study was performed in children with AA who underwent surgery between March 9 and April 13 from 2015 to 2020; patients were divided into six groups according to the year of surgery. We analyzed demographic variables, time from onset of symptoms, mean hospital stay, cumulative incidence, and incidence rate of complicated appendicitis.

Results A total of 168 patients were included with no differences in the number of patients, gender, and age between groups. Patients in 2020 (COVID-19 group) presented longer symptom progression time (46.8 hours; p = 0.046), higher rate of complicated appendicitis (48.4%; p = 0.004), longer mean hospital stay (4.9 days; p < 0.001), increased cumulative incidence (8.27 cases per 100,000 children per 0.1 years; p < 0.001), and increased incidence rate of complicated appendicitis (83 cases per 100,000 children; p < 0.001) when compared with other groups.

Conclusion Delayed ED visit of children with AA during home confinement lead to an increased rate of complicated appendicitis. It is crucial to make parents aware of the importance of early diagnosis and treatment of abdominal pain.
Injury Patterns in Pediatric Facial Fractures Unique to an Urban Environment
Authors: Sclafani Anthony P. , Sclafani Matthew Scott , Long Sallie , Losenegger Tasher , Spielman Daniel , Obayemi Ade , Cosiano Michael F. , Neuner Romy , Kacker Ashutosh , Reeve Gwendolyn , Stewart Michael G.
Published: February 2021

This study aimed to define better the clinical presentation, fracture patterns, and features predictive of associated injuries and need for surgery in pediatric facial trauma patients in an urban setting. Charts of patients 18 years or younger with International Classification of Disease 9th and 10th revision (ICD-9/ICD-10) codes specific for facial fractures (excluding isolated nasal fractures) at NY-Presbyterian/Weill Cornell Medical Center between 2008 and 2017 were retrospectively reviewed. Of 204 patients, most were referred to the emergency department by a physician's office or self-presented. Children (age 0–6 years) were most likely to have been injured by falls, while more patients 7 to 12 years and 13 to 18 years were injured during sporting activities (p < 0.0001). Roughly half (50.5%) of the patients had a single fracture, and the likelihood of surgery increased with greater numbers of fractures. Older patients with either orbital or mandibular fractures were more likely to undergo surgery than younger ones (p = 0.0048 and p = 0.0053, respectively). Cranial bone fractures, CSF leaks, and intracranial injuries were more common in younger patients (p < 0.0001) than older patients and were more likely after high energy injuries; however, 16.2% of patients sustaining low energy injuries also sustained cranial bone, CSF leak, or intracranial injury. In an urban environment, significant pediatric facial fractures and associated injuries may occur after nonclassic low kinetic energy traumatic events. The age of the patient impacts both the injuries sustained and the treatment rendered. It is essential to maintain a high index of suspicion for associated injuries in all pediatric facial trauma patients.
Ultrahigh vacuum packaging and surface cleaning for quantum devices
Authors: Mergenthaler M. , Paredes S. , Müller P. , Müller C. , Filipp S. , Sandberg M. , Hertzberg J. B. , Adiga V. P. , Brink M. , Fuhrer A.
Published: February 2021

We describe design, implementation, and performance of an ultra-high vacuum (UHV) package for superconducting qubit chips or other surface sensitive quantum devices. The UHV loading procedure allows for annealing, ultra-violet light irradiation, ion milling, and surface passivation of quantum devices before sealing them into a measurement package. The package retains vacuum during the transfer to cryogenic temperatures by active pumping with a titanium getter layer. We characterize the treatment capabilities of the system and present measurements of flux tunable qubits with an average T1 = 84 µs and T2echo=134 μs after vacuum-loading these samples into a bottom loading dilution refrigerator in the UHV-package.
Carbon nanostructure containing plasma: Medium for efficient high-order harmonics of 1030 nm laser
Authors: Kim Vyacheslav V. , Ganeev Rashid A. , Boltaev Ganjaboy S. , Iqbal Mazhar , Alnaser Ali S.
Published: February 2021

We analyze the high-order harmonics generation from the plasmas produced on the carbon-containing targets (graphite, fullerenes, and carbon nanotubes) using near infrared laser radiation. This approach utilizes two synchronized laser sources: one (6 ns, 1064 nm) for creating optimal laser-induced plasma and the other (40 fs, 1030 nm) for generating high-order harmonics, which allowed for analyzing the evolution of different plasma plumes up to longer delays from the beginning of ablation. The role of different carbon-based nanostructures in the frequency conversion of laser pulses is studied at different conditions of plasma formation. We show that all carbon clusters and nanostructures acquire from the very beginning approximately the same kinetic energy and spread out of the surface with velocity that is similar to the one that is possessed by a single carbon atom ablated from bulk material.
Suppression of power losses during laser pulse propagation in underdense plasma slab
Authors: Lezhnin K. V. , Qu K. , Fisch N. J.
Published: February 2021

For current state-of-the-art terawatt lasers, the primary laser scattering mechanisms in plasma include forward Raman scattering (FRS), excitation of plasma waves, and the filamentation instability. Using 2D particle-in-cell (PIC) simulations, we demonstrate that FRS dominates in the regime with medium-to-low density plasma and non-relativistic laser fields. We numerically show that FRS can be suppressed using a two-color laser with frequency detuning exceeding the plasma frequency, Δω>ωpe, leading to a more efficient laser energy transmission. An optimal laser pulse energy redistribution ratio is predicted analytically and verified by PIC simulations.
Graphene-anode thermionic converter demonstrating total photon reflection
Authors: Hu Cong , Liang Tao , Chen Xiaohang , Su Shanhe , Chen Jincan
Published: February 2021

An updated thermionic converter was established through the introduction of a graphene anode and an optical reflector, significantly decreasing the irreversible losses inside the device and enhancing the device performances. At 1940 K, the maximum efficiency and power output density of the converter reached 76.6% and 95.1 W cm−2. The optimum performances of the proposed model were obviously better than those achieved using a graphene-anode thermionic converter without a reflector and a traditional thermionic converter with a metal anode. Importantly, the optimal regions of the key parameters were determined for the different temperatures of the heat source and the parametric selection criteria and design strategies for the proposed model are also provided. These are extremely important as they may facilitate the implementation of the device.
Accurate quantum dynamics simulation of the photodetachment spectrum of the nitrate anion (NO3−) based on an artificial neural network diabatic potential model
Authors: Viel Alexandra , Williams David M. G. , Eisfeld Wolfgang
Published: February 2021

The photodetachment spectrum of the nitrate anion (NO3−) is simulated from first principles using wavepacket quantum dynamics propagation and a newly developed accurate full-dimensional fully coupled five state diabatic potential model. This model utilizes the recently proposed complete nuclear permutation inversion invariant artificial neural network diabatization technique [D. M. G. Williams and W. Eisfeld, J. Phys. Chem. A 124, 7608 (2020)]. The quantum dynamics simulations are designed such that temperature effects and the impact of near threshold detachment are taken into account. Thus, the two available experiments at high temperature and at cryogenic temperature using the slow electron velocity-map imaging technique can be reproduced in very good agreement. These results clearly show the relevance of hot bands and vibronic coupling between the X̃ 2A2′ ground state and the B̃ 2E′ excited state of the neutral radical. This together with the recent experiment at low temperature gives further support for the proper assignment of the ν3 fundamental, which has been debated for many years. An assignment of a not yet discussed hot band line is also proposed.
Effect of side chain modifications in imidazolium ionic liquids on the properties of the electrical double layer at a molybdenum disulfide electrode
Authors: Gong Zheng , Padua Agilio A. H.
Published: February 2021

Knowledge of how the molecular structures of ionic liquids (ILs) affect their properties at electrified interfaces is key to the rational design of ILs for electric applications. Polarizable molecular dynamics simulations were performed to investigate the structural, electrical, and dynamic properties of electric double layers (EDLs) formed by imidazolium dicyanamide ([ImX1][DCA]) at the interface with the molybdenum disulfide electrode. The effect of side chain of imidazolium on the properties of EDLs was analyzed by using 1-ethyl-3-methylimidazolium ([Im21]), 1-octyl-3-methylimidazolium ([Im81]), 1-benzyl-3-methylimidazolium ([ImB1]), and 1-(2-hydroxyethyl)-3-methylimidazolium ([ImO1]) as cations. Using [Im21] as reference, we find that the introduction of octyl or benzyl groups significantly alters the interfacial structures near the cathode because of the reorientation of cations. For [Im81], the positive charge on the cathode induces pronounced polar and non-polar domain separation. In contrast, the hydroxyl group has a minor effect on the interfacial structures. [ImB1] is shown to deliver slightly larger capacitance than other ILs even though it has larger molecular volume than [Im21]. This is attributed to the limiting factor for capacitance being the strong association between counter-ions, instead of the free space available to ions at the interface. For [Im81], the charging mechanism is mainly the exchange between anions and octyl tails, while for the other ILs, the mechanism is mainly the exchange of counter-ions. Analysis on the charging process shows that the charging speed does not correlate strongly with macroscopic bulk dynamics like viscosity. Instead, it is dominated by local displacement and reorientation of ions.
Rapid Ca
2+
channel accumulation contributes to cAMP-mediated increase in transmission at hippocampal mossy fiber synapses
Authors: Fukaya Ryota , Maglione Marta , Sigrist Stephan J. , Sakaba Takeshi
Published: February 2021

Significance

Despite the importance of the activation of the cAMP/PKA signaling pathway for presynaptic modulation, its cellular and molecular mechanisms remain unclear. In this study, we tackled this issue at hippocampal mossy fiber-CA3 synapses by combining paired electrophysiological recordings, Ca
2+
uncaging, total internal reflection fluorescence (TIRF) microscopy for direct measurements of presynaptic active zone Ca
2+
influx, and superresolution time-gated STED microscopy for visualization of Ca
2+
channel clusters within active zones. Our results suggest that Ca
2+
channels near release sites might accumulate upon activation of the cAMP/PKA pathway in the time scale of only several minutes. Our findings may thus change the focus from release machinery to Ca
2+
channel clusters and their dynamics as a cell biological mechanism of cAMP-dependent synaptic modulation.
Samir Amin and Eastern Europe
Authors: Artner Annamária
Published: February 2021

This debate discusses four aspects of Samir Amin’s thoughts regarding Eastern Europe: Amin’s overall evaluation of the Soviet bloc; the relevance of his concepts on the centrality of the periphery; the ‘long transition to socialism’; and the role of nationalism and Eurocentrism in Eastern Europe. The author concludes that Eastern Europe does not fit into the historical role of the periphery as understood by Amin, and that the Eurocentric nationalism of the region serves to promote global capitalism instead of helping to further the anti-capitalist struggle.
Antiphospholipid antibodies in COVID-19-associated pneumonia patients in intensive care unit
Authors: Karahan Samet , Erol Kemal , Yuksel Recep Civan , Artan Cem , Celik Ilhami
Published: February 2021

Objectives

Antiphospholipid antibodies (APAs) increase the risk of excessive blood clotting, but their role in COVID-19 remains unclear. We aimed to investigate the presence of conventional APAs used in the classification of antiphospholipid antibody syndrome in patients with severe lung infection with SARS-CoV-2 and to compare these results with non-COVID-19 critically ill patients

Methods

Thirty-one COVID-19 patients (COVID group) and 28 non-COVID-19 critically ill patients (non-COVID group), were included in the study. Anti-cardiolipin (ACA) (IgG, IgM), anti-β2-glycoprotein 1 (Anti-β2GPI) (IgG, IgM, and IgA), and if the patient had not received any anti thrombotic agent before blood collection, lupus anticoagulant (LAC) tests were studied from the plasma of the patients. For testing ACA and Anti-β2GPI, ELISA method was used, while fully automated coagulometer device was used for LAC test.

Results

APAs were positive in 25.81% in the COVID group (8/31) and 25% in the non-COVID group (7/28). LAC was the most common APA present in 23.08% of the COVID-19 group, who underwent measurement (6/26), while 3.57% of the non-COVID group was LAC positive (1/28) (p = .047). In the COVID group, ACA IgM, and IgG were positive in 6.45% and 0%, respectively (2/31 vs 0/31). In the non-COVID group, ACA IgM was not positive in any patient, while ACA IgG was positive in 7.14% (2/28). Anti-β2GPI IgG and IgM tests were not positive in any patient in either the COVID or the non-COVID group. Anti-β2GPI IgA were positive in 6.45% and 14.29%, respectively (2/31 vs 4/28).

Conclusion

In this study, APAs were equally positive in critically ill patients among COVID-19 or non-COVID-19 patients. Only LAC was more observed in COVID-19 patients.

Key messages
Starting a lab during the COVID-19 pandemic
Authors: Casadio Melina , Simon Dan
Published: February 2021

JCB asks early career investigators to share their experience launching a lab during the COVID-19 pandemic.
Lange on Minimal Model Explanations: A Defense of Batterman and Rice
Authors: McKenna Travis
Published: February 2021

Marc Lange has recently raised three objections to the account of minimal model explanations offered by Robert Batterman and Collin Rice. In this article, I suggest that these objections are misguided. I suggest that the objections raised by Lange stem from a misunderstanding of the what it is that minimal model explanations seek to explain. This misunderstanding, I argue, consists in Lange’s seeing minimal model explanations as relating special types of models to particular target systems rather than seeing minimal model explanations as looking to explain robust patterns of behavior that are exhibited by a variety of physically diverse systems.
A Problem for Confirmation Measure Z
Authors: Fitelson Branden
Published: February 2021

In this article, I present a serious problem for confirmation measure Z.
Stability of the Hayward black hole under electromagnetic perturbations
Authors: Villani Mattia
Published: February 2021

It is known that the regular Hayward black hole is an exact solution of the Einstein equations which describes a non-rotating magnetic monopole governed by a non linear Lagrangian. We consider the problem of electromagnetic perturbations of such an object in order to study its stability.
Measuring the Earth’s albedo with simple instruments
Authors: Kraus Simon F
Published: February 2021

The Earth’s albedo, as the fraction of sunlight that is directly reflected back into space from the surface or clouds, is a key factor in modeling Earth’s climate. In tasks such as the simplified estimation of the mean temperature, it is usually given as a constant, without mentioning its determination and the associated difficulties. In fact, the albedo can be determined by a basically simple procedure based on the observation of a well-known phenomenon: Earth’s shine. A comparison of the intensities between the directly illuminated side of the Moon and the side illuminated by Earth’s shine provides the mean albedo for a large part of the Earth’s surface. In this paper, the procedure will be reproduced using simple instruments. Assuming the reflection properties of a Lambert sphere—an ideal diffuse reflecting body—for the Earth, and using measurements of the phase function—as a description for the angular distribution of the scattered light—of the Moon, the Earth’s albedo is determined from self-acquired data. Even with these simple conditions it is possible to come quite close to the value of the Earth’s albedo.
Pathway towards 24% efficiency for fully screen-printed passivated emitter and rear contact solar cells
Authors: Zhang Yuchao , Wang Li , Chen Daniel , Kim Moonyong , Hallam Brett
Published: February 2021

In this work, the efficiency potential of the fully screen-printed passivated emitter and rear contact (PERC) solar cell structure is investigated via numerical simulations. A series of improvements and optimizations are performed on bulk quality, emitter properties and metallization of screen-printed PERC solar cells based on experimental results obtained in both industry and laboratory environments. With significantly improved bulk and surface passivation quality, we find that carrier recombination losses at the metal/silicon interface will impose a substantial limitation on efficiencies, highlighting the need for developing new screen-printing technologies to overcome the limitation from contact recombination. By improving the effectiveness of the back-surface field, reducing coverage area of laser-doped selective emitters and the front metal/silicon interface contact area, a 15 mV improvement in open-circuit voltage (V
OC) was achieved in our modelled cells, due to greatly reduced contact recombination losses. With the further implementation of a multi-busbar and fine-line printing technologies, efficiency above 24% was obtained from simulations. Subsequently, a comprehensive pathway towards 24% efficiency for screen-printed PERC solar cells is proposed, without the need to implement passivated contacts or transition to a plated metallisation scheme. Key target requirements for future developments are also identified.
New insights into sub-barrier fusion of 28Si + 100Mo
Authors: Stefanini A M , Montagnoli G , D’Andrea M , Giacomin M , Dehman C , Somasundaram R , Vijayan V , Zago L , Colucci G , Galtarossa F , Goasduff A , Grebosz J
Published: February 2021

Fusion cross sections of the 28Si + 100Mo system have been measured near and below the Coulomb barrier by detecting the evaporation residues at forward angles. The excitation function has an overall smoother trend than what obtained in a previous experiment, and a large discrepancy is found for the lowest-energy region, where we observe a tendency of the S factor to develop a maximum, which would be a clear indication of hindrance. The results have been compared with the theoretical prediction of coupled-channels calculations using a Woods–Saxon nuclear potential, and including the low-energy excitation modes of both nuclei. Good agreement with data is found by including, in the coupling scheme, the three lowest members of the ground state rotational band of the oblate deformed 28Si, and two-phonons of the strong quadrupole vibration of 100Mo. The additional coupling, in a schematic way, of the two-neutron pick-up between ground states (Q-value = +4.86 MeV) has a minor effect on calculated cross sections, and does not essentially improve the data fit. The excitation function of 28Si + 100Mo has been compared with that of (1) the heavier system 60Ni + 100Mo having analogous features, and (2) several near-by 28Si, 32S + Zr, Mo systems with various nuclear structures and transfer Q-values. The role of quadrupole and octupole excitation modes, as well as of transfer channels, in affecting the fusion dynamics, are clarified to some extent. Systematic measurements of fusion barrier distributions and CC calculations properly including transfer couplings, are necessary, in order to shed full light on the influence of the various coupled channels on the fusion cross sections.
First-principles calculation of atomic structure, stability and electronic structure of TaB2/SiC interface
Authors: Cheng Gong , Xiong Yuqing , Zhou Hui , He Yanchun , Zhang Kaifeng , Cao Shengzhu , Wang Keliang
Published: February 2021

The atomic structure, interface stability and electronic interaction of TaB2(0001)/SiC(111) interfaces were investigated by first principles calculation. The study found that the termination atom and stacking position are the key factors affecting the bonding strength and stability of the interface. On the basis of considering work of adhesion (W
ad) and interfacial energy (γ
int), the Ta–TaB2/C–SiC center-site stacked (Ta–CS–C) and B–TaB2/C–SiC center-site stacked (B–CS–C) configurations are recognized as the most stable structures from ten TaB2/SiC interface models. Electronic interaction of the two most stable interfaces were revealed by analyzing the charge density distribution, charge density difference and partial density of states, and found that ionic and metallic bond coexisted in Ta–CS–C interface, while covalent bond played a dominant role in B–CS–C interface.
Rational design of π bridge to forecast photoelectric performance of dye
Authors: Ren Penghui , Liu Anmin , An Maozhong
Published: February 2021

The conjugate bridge plays an important role in the D–π–A sensitizers, which affects the optical properties, energy levels and electron transfer from donor to acceptor unit. The transfer and securing abilities of conjugate bridge is a necessary conditions to raise the red-shift absorption band, light harvesting ability. In this paper, the effect of conjugate bridge in the D–π–A sensitizers, such as benzene, thiophene, bithiophene, 4-(thiophen-2-yl)benzo[c] [1,2,5]thiadiazole, 4-(thiophen-2-yl)benzo[c] [1,2,5]thiadiazole, terthiophene and so on, which were studied to predict the photoelectric properties of molecules. The ground-state structure and excited-state properties of the dyes and dyes/TiO2 were calculated using density functional theory (DFT) and time-dependent density functional theory (TD-DFT). The short circuit density (J
sc), open-circuit voltage (V
oc), fill factor (FF), and photo-to-electric conversion efficiency (η) are critical factors for dye-sensitized solar cells (DSSCs). Then, this method not only considered the relationship between macroscopic phenomena and macroscopic properties but also reasonably selected the dye molecules suitable for dye batteries.
Lead halide perovskites with aggregation-induced emission feature coupled with gold nanoparticles for fluorescence detection of heparin
Authors: Qu Fei , Yin Tian , Fa Qianqian , Jiang Dafeng , Zhao Xian-en
Published: February 2021

Herein, a new kind of lead halide perovskite (LHP, (C12H25NH3)2PbI4) with aggregation-induced emission (AIE) feature is developed as a fluorescent probe for heparin (Hep). The LHPs exhibit high emission when they aggregate in water. Interestingly, a few picomoles of dispersed gold nanoparticles (AuNPs) can quench the emission of LHPs, but the aggregated AuNPs are invalid. When protamine (Pro) is mixed with AuNPs at first, the negatively charged AuNPs aggregate through electrostatic interaction, producing the AIE recovery. Nevertheless, Hep disturbs the interaction between AuNPs and Pro due to its strong electrostatic interaction with Pro. Therefore, the dispersed AuNPs quench the fluorescence of LHPs again. A response linear range of Hep of 0.8–4.2 ng ml−1 is obtained, and the detection limit is 0.29 ng ml−1. Compared with other probes for determination of Hep with AuNPs, this strategy exhibits better sensitivity due to the small quantity of AuNPs used. Finally, it is also successfully applied to detect Hep in human serum samples with satisfactory recoveries.
On the rotational–translational equilibrium in non-thermal argon plasmas at atmospheric pressure
Authors: Labelle Francis , Durocher-Jean Antoine , Stafford Luc
Published: February 2021

This work examines the rotational–translational equilibrium in non-thermal, argon-based plasmas at atmospheric pressure. In particular, rotational temperatures (T
rot) and neutral gas temperatures (T
g) are compared along the axis of plasma columns sustained by either radiofrequency (RF) or microwave (MW) electromagnetic fields. Water vapours or N2 admixtures are added to the high-purity argon plasmas to record the rotational temperatures from the emission spectra of either the OH(A2Σ
+
− X2Π
i
) or the N2
+(B2Σ
u

+
− X2Σ
g

+
) rovibrational systems. T
g values are also deduced from the line broadening of selected Ar emission lines using an hyperfine spectrometer. In the MW Ar/H2O plasma, T
g decreases from ∼2100 K close to the wave launcher to ∼1600 K near the end of the plasma column, while T
rot is mostly constant in the 1500 K range. In presence of N2 admixtures instead of water vapours, T
g is higher by about 300 K (from ∼2400 K to ∼1900 K), while T
rot decreases from ∼3200 K to ∼2750 K along the plasma column. A discrepancy between T
g and T
rot is also observed in the much colder RF plasmas with T
g ∼ 400 K and T
rot ∼ 515 K. Such departure from the rotational–translational equilibrium in both plasmas is ascribed to the influence of electrons competing with neutrals to impose their own temperature on the distribution of rotational levels of both ground and excited states.
Quantum blackbody thermometry
Authors: Norrgard Eric B , Eckel Stephen P , Holloway Christopher L , Shirley Eric L
Published: February 2021

Blackbody radiation sources are calculable radiation sources that are frequently used in radiometry, temperature dissemination, and remote sensing. Despite their ubiquity, blackbody sources and radiometers have a plethora of systematics. We envision a new, primary route to measuring blackbody radiation using ensembles of polarizable quantum systems, such as Rydberg atoms and diatomic molecules. Quantum measurements with these exquisite electric field sensors could enable active feedback, improved design, and, ultimately, lower radiometric and thermal uncertainties of blackbody standards. A portable, calibration-free Rydberg-atom physics package could also complement a variety of classical radiation detector and thermometers. The successful merger of quantum and blackbody-based measurements provides a new, fundamental paradigm for blackbody physics.
Insights into the physical properties of inverse-Heusler alloy Cr2CoGa via density functional theory
Authors: Hasan Md Zahid , Rayhan M A , Rahman Md Atikur , Rasheduzzaman Md , Modak Jibon Krishna , Hossain Khandaker Monower
Published: February 2021

First-principles analyses are accomplished on the structural, mechanical, thermal, electronic, and optical properties of inverse-Heusler alloy Cr2CoGa using density functional theory. Our determined lattice parameters agree very well with prior findings. The mechanical properties of both cubic and tetragonal phases of Cr2CoGa compound are thoroughly investigated. The elastic constants meet the Born criteria for mechanical stability of the studied compound. The ductile behavior is exhibited by the calculated Pugh’s ratio 2.66 and 2.91 as well as the Poisson’s ratio 0.33 and 0.35 for cubic and tetragonal phase, respectively, and the tetragonal phase is more ductile comparing this two phases. The universal elastic anisotropy of cubic and tetragonal Cr2CoGa is 0.25 and 0.28, respectively, revealing their anisotropic nature, which is also confirmed by the non-spherical 3D anisotropy contour plots. The estimated Debye temperature and minimum thermal conductivity suggest potential application of Cr2CoGa as a thermal barrier coating. The calculated electronic band structure and density of states suggest the metallic characteristics of Cr2CoGa. Moreover, the important optical parameters, namely, dielectric constants, refractive index, absorption coefficient, photoconductivity, reflectivity, and loss function are also investigated and discussed towards the efficient applications of Cr2CoGa.
Refractive index Mach–Zehnder interferometer sensor based on tapered no-core fiber
Authors: Zhao Yeming , Tong Zhengrong , Zhang Weihua , Zhang Jietong , Li Jiaxin , Wang Xue
Published: February 2021

A Mach–Zehnder interferometer sensor based on tapered no-core fiber (NCF) is proposed in this paper. Due to the multimode interference of the single-mode fiber (SMF)–NCF–SMF structure and the higher-order modes excited by the tapered structure, the sensor is more sensitive to the refractive index. The refractive index sensitivities are 130.5 nm RIU−1 from 1.340 to 1.380, 330.0 nm RIU−1 from 1.380 to 1.420, and 906.0 nm RIU−1 from 1.420 to 1.440, respectively. The temperature sensitivity is 0.0595 nm °C−1 from 30 °C to 90 °C. This proposed sensor has a simple structure and low cost, which can be widely used for biological sensing.
Simulation of neutron-tagged deep inelastic scattering at EicC *
Authors: Xie Gang , Li Meng-Yang , Han Cheng-Dong , Wang Rong , Chen Xurong
Published: February 2021

Measuring the pionic structure function is of high interest, as it provides a new area for understanding the strong interaction among quarks and testing QCD predictions. To this end, we investigate the feasibility and expected impact of a possible experiment at EicC (Electron-ion collider in China). We show the simulation results on the statistical precision of an EicC measurement, based on the model of leading neutron tagged DIS process and the parton distribution functions of the pion from JAM18 global analysis. The simulation shows that at EicC, the kinematics cover the

range from 0.01 to 1, and the

range from 1 to 50 GeV

, within the acceptable statistical uncertainty. Assuming an integrated luminosity of 50 fb

, in the low-

region (

GeV

), the Monte Carlo data show that the suggested measurement in the whole

range reaches very high precision (

%). To perform such an experiment, only the addition of a far-forward neutron calorimeter is needed.
The value of stable, comparable and standardised measurement: enabling confidence in decision making for societal challenges
Authors: Brown Richard J C , Janssen Jan-Theodoor
Published: February 2021

Making decisions that have broad societal and economic impact is extremely hard. This is especially true when the data upon which choices for future action are based are unstable or have uncertain provenance. This letter discusses the benefits of metrology, as the science of measurement, in providing data that is stable, comparable and produced using standardised methods, in enabling greater confidence in the decision-making process. A key part of this increased confidence is via providing input data with reduced uncertainty, thereby decreasing the uncertainty of future predictions. The application of these principles to the two biggest societal challenges currently, COVID-19 and climate change, is discussed, and similarities and differences of approaches highlighted. It is foreseen that the role of metrology in enabling evidence-based decision making will become increasingly more important in future. Formal agreements and memoranda of understanding between the metrology community and the relevant global technical bodies are the best way to improve data quality, reliability and comparability, and therefore the confidence with which decisions can be made. Whilst uncertainties in data may be driven down as technology and metrology improves, they can never be eliminated entirely, and we must accept some level of uncertainty in our decision making.
Traffic dynamics of uni- and bidirectional pedestrian flows including dyad social groups in a ring-shaped corridor
Authors: Ye Rui , Fang Zhiming , Lian Liping , Wang Qiao , Zeng Guang , Cao Shuchao , Zhang Jun , Song Weiguo
Published: February 2021

In this paper, we introduce dyad social groups into the experiment to mimic uni- and bidirectional pedestrian flows that are closer to real life. According to the experimental videos, different strategies of collision avoidance for dyads are observed and classified. Moreover, we observe an interesting lane-merging phenomenon in bidirectional scenarios. Fundamental diagrams are calculated based on two measurement methods, and further compared with previous individual experiments (without dyads), confirming the negative impact of social groups due to their inherent cohesion during the movement process. Then, group characteristics such as group distance and spatial alignment are analyzed under the influence of different global densities. It is interesting to note that the effect of density on spatial alignment distribution is opposite in uni- and bidirectional scenarios, i.e. the increasing density will make the distribution less scattered in the unidirectional flow, which is contrary to the phenomenon in the bidirectional flow. Finally, based on the time evolution of congestion level and crowd danger, they can be good indicators of transitions from disorder to order, especially in bidirectional scenarios. Furthermore, the differences between uni- and bidirectional flows can be well distinguished through the relations between density and congestion level, as well as crowd danger.
ITNT Proceedings Preface Proceedings of the VI International Conference on Information Technology and Nanotechnology (ITNT-2020); 26-29 May 2020, Samara, Russia
Authors: Kozlova E
Published: February 2021

The VI International Conference on Information Technology and Nanotechnology (ITNT-2020: http://itnt-conf.org/) was held in Samara, Russia, May 26-29, 2020, at Samara National Research University and Image Processing Systems Institute of RAS. Due to the COVID-19 pandemic, the Conference has to be moved to a virtual regime. Despite the new format, the ITNT-2020 gathered a large quorum of participants, who presented more than 500 talks in different actual topics of modern science. These proceedings of the VI International Conference on Information Technology and Nanotechnology contain 120 papers which have been peer-reviewed by special Committee of Editors to guarantee high quality and novelty of presented research. The topics discussed include computer optics, nanophotonics, mathematical modeling of physico-technical processes and systems.
Structural features of the near-surface layers of highly diluted aqueous solutions
Authors: Shostka V I , Shostka N V , Halilov S I , Vershitsky V I
Published: February 2021

Particular importance currently is given to highly diluted aqueous solutions due to the fact that not only the presence of clusters, but also more complex structures – associates, bastons, etc., have been found in them. However, the phenomenon of the appearance of new physicochemical, spectral, diffraction, refractometric and other effects related to heterogeneity in the changing inhomogeneous structure of the surface layers of aqueous solutions is not fully understood. The paper presents the results of vertical laser sensing of drops of hydrophilic substances highly diluted in water, which made it possible to detect clathrate nano-formations in various combinations, the nature of which is still insufficiently clear. We studied droplets of distilled micellar water, hydrogen peroxide, an aqueous solution of glycerol, ethanol, etc. At low concentrations of hydrophilic substances in aqueous solutions their molecules are embedded into the interstices of the water lattice without causing destruction of its structure. It is found that the dissolution mechanism continued only to a certain critical concentration after which “saturation” occurred. A further increase in the content of dissolved substances in aqueous solutions leads to the destruction of the ordered structure, and the excess molecules of the hydrophilic substance, combined together, form complex aggregates or their “islands”.
Development and investigation of micro- and nanostructures of metamaterials to form the necessary characteristics and coefficients of piezoelectric elements
Authors: But V S , Kobelev A A , Karlin E S , Karpeev S V
Published: February 2021

The development and research of micro and nanostructures for the manufacture of ultrasonic piezoacoustic elements has been carried out. The structures obtained in this work have practical applications for the manufacture of piezoelectric and piezoacoustic elements, in particular, for using in liquid flowmeters as receivers and emitters of an ultrasonic signal. A structure of nanocells was obtained that was different from standard piezoelectric elements (disk, cylinder), but with the same coefficients, characteristics, and radiation pattern.
Analysis focused image formation in double exposure speckle photography
Authors: Osipov M N , Sergeev R N
Published: February 2021

This paper presents the theoretical and experimental results of the analysis of the formation of the focused image in a double-exposure speckle photography. Theoretical analysis of the formation of the focused image in double-exposure speckle photography was carried out using the Vander Lugt method. It is shown that as a result of the summation of speckle structures displaced in the space of the photographic plates, moiré fringes are formed in double-exposure speckle photography. Experimental results confirming theoretical studies are presented.
Simulation of light focusing by a dielectric microcylinder with a metal film and gap on shadow side
Authors: Savelyeva A A , Kozlova E S
Published: February 2021

In this work, using the FullWAVE software package, numerical simulation of focusing of TM-wave with a wavelength of 633 nm was performed. It is shown that a dielectric microcylinder made of polyester with a radius of 2.1749 of wavelength coated on the shadow side with a silver film of 90 nm with a 100 nm hole, allows to get a focus with a maximum intensity of 1.37 times more (10.61 a. u), than a conventional dielectric cylinder (7.73 a. u).
The formation of an array of photonic nanojets by steps with square profile
Authors: Zaitsev V D , Stafeev S S
Published: February 2021

Modeling the finite-difference time-domain method (FDTD) using the software package FullWAVE focusing Gaussian beam width of 5.4 um and a wavelength of 0.633 um using a binary grating made of silica (refractive index 1.46) showed that the individual steps relief near its output surface form the focal spots - photonic nanojet. This photonic nanojet bent at the wavefront tilt.
Multifunctional fiber optic system for microwave signals transmitting in frequency range from 0.135 to 40 GHz
Authors: Pchelkin G A , Yu Rud V , Davydov V V
Published: February 2021

In article of the developed design of a fiber-optic system for transmitting microwave signals in radar is presented. The using the developed design of a fiber optic transmission system of microwave signal allows to increase the range of operating frequencies of the radar at least twice as well as its functional capabilities. The new method of realization design of a fiber optic transmission system of microwave signal is proposed. Its use allowed to reduce in the fiber optic system, the number of functional blocks in this frequency range of the radar work on the compared to previously used designs. The experimental research results are presented.
Modelling of temperature fields in DP1000 steel during laser treatment using diffractive optical elements
Authors: Bielak R , Murzin S P , Liedl G , Otto A , Kazanskiy N L
Published: February 2021

Diffractive optical elements (DOEs) with their unique properties allow to form a predetermined beam intensity profile in the focal plane. The use of DOEs in laser material processing technologies reveals new possibilities for controlling the properties and operational characteristics of processed parts. The beam intensity profile formed by DOE is presented in the form of an analytical expression that was used to set a surface heat source for modelling thermal processes in DP 1000 steel. Experimental studies of samples under laser heating were performed. Simulation output results correlate well with the experimental data. The proposed simulation model, based on a precise heat input definition, is an intermediate step to the final goal, which is the prediction of structural changes in the zone of laser beam irradiation.
Experimental study of spatial frequency transition of laser induced periodic surface structures
Authors: Fuerbacher R , Liedl G , Murzin S P
Published: February 2021

This study shows the influence of laser fluence and pulse number on the spatial frequency distribution of laser induced periodic surface structures (LIPSS) on a stainless steel surface. Also the transition of LIPSS to larger self organized, periodic, cone-like structures has been investigated. The experiments were carried out using a Ti:Sapphire femtosecond laser system with 800 nm centre wavelength, a pulse duration of 30 fs and a repetition rate of 1 kHz. Experiments have been carried out on flat, cold-rolled stainless steel surfaces (1.4301) by variation of the laser output power and feed rate. It could be shown, that the transition of low spatial frequency LIPSS (LSFL) to high spatial frequency LIPSS (HSFL) is a continuous process, strongly depending on the laser single pulse fluence and the pulse number. At higher accumulated fluences the transition of LIPSS to larger self organized structures could be observed. As a result, hierarchical structures were created with micrometer-sized cones at the bottom and nanometer-sized LIPSS on top. By further increasing the accumulated fluence, the grooves between the micro structures are widened until the ablation threshold of the alloy is reached. These hierarchical structures could be of considerable value in improving wetting properties of technical surfaces.
Silicon subwavelength axicons for terahertz beam polarization transformation
Authors: Pavelyev V S , Degtyarev S A , Tukmakov K N , Reshetnikov A S , Knyazev B A , Choporova Yu Yu
Published: February 2021

The diffractive optical element (DOE) for transforming of linearly polarized THz radiation beam into a cylindrically polarized beam is investigated. Optimal diffractive microrelief height is determined by numerical simulation.