bluuebunny/crossref_metadata_2025 huggingface dataset:
Biotechnological preparation of sewage and livestock manure from livestock farms for the needs of horticulture
Authors: Bondarenko Anatoly , Kachanova Liudmila , Kolosov Yuri , Shakhmurzova Agnessa , Bittirov Anatoly
Published: May 2021

Ensuring food security of the state provides for obtaining high yields of agricultural crops and the development of livestock facilities. The aim of the investigation is to develop an accelerated biotechnological preparation of sewage and livestock manure from livestock farms for irrigation of pastures and fertilization of fields for forage crops. Closed-loop systems for products output on pig farms and cattle farms using biotechnology for the preparation of livestock manure for irrigation of fields in the production of forage crops have been developed. The biotechnology of accelerated preparation of sewage and liquid livestock manure is based on the principles of their mechanical separation into fractions with the subsequent preparation of liquid concentrated organic fertilizers using nutraceuticals, which speed up the processes of their preparation in a much shorter time than using traditional technologies. A closed-loop system for products output on sheep and pig farms and cattle farms using biotechnology is proposed. The basis of biotechnology in the processing of solid livestock manure is the principle of accelerated components composting using nutraceuticals. The implementation of accelerated preparation system of sewage and livestock manure for irrigation of pastures and fertilization of fields for forage crops contributed to an increase in their yield up to 20.54%. At the same time, the milk yield per forage cow increased by 8.47-14.20%; average daily weight gain - by 13.30–47.73%.
Biotical cycle in single-crop sowing and mixed agrophytocenosis of forage crops
Authors: Tamahina Aida , Turabov Urfa Turan Ogly
Published: May 2021

The biotic cycle is based on the assessment of chemical elements in the production, degradation processes, during the deposition and resynthesis of organic compounds. The biotic cycle of agrophytocenoses, in contrast to natural ecosystems, is characterized by a significant imbalance of macro- and microelements. One way of solving this problem is to approximate the composition and structure of agrophytocenoses to natural plant communities. The objective of the research was to investigate the biotic cycle of elements in single- and mixed-seeded crops of Galega orientalis Lam., Inula helenium L., Symphytum asperum Lepech., urtica dioica L. The research was conducted in the mountainous zone of the Kabardino-Balkarian Republic in 2015-2019 on grey forest soil. In mixed agrophytocenoses, the biotic balance becomes less negative compared to monoculture crops. The excess of consumption over the return of N, Ca, K, P to the soil averaged 3.96; 40.94; 334.02; 9.46 kg/ha, respectively, over 5 years. The inclusion of Galega orientalis in a mixture with nonlegurninous forage grasses increased the soil cultivation index from 0.87 to 0.90. The results show the high potential of a polyculture system based on the combined cultivation of legumes and non-legumes in increasing the sustainability of farming.
Comparative analysis of the stock quotes dynamics for IT-sector and the entertainment industry companies based on the characteristics of memory depth
Authors: Maksyshko Nataliia , Vasylieva Oksana
Published: May 2021

The article is devoted to the study and comparative analysis of the stock quotes dynamics for the world’s leading companies in the IT sector and the entertainment industry. Today, these areas are developing the fastest and most powerful, which attracts the attention of investors around the world. This is due to the rapid development of digital communication technologies, the growth of intellectualization and individualization of goods and services, and so on. These spheres have strong development potential, but the question to how their companies’ stock quotes respond to the impact of such a natural but crisis phenomenon as the COVID-19 pandemic remains open. Based on the nonlinear paradigm of the financial markets dynamics, the paper considers and conducts a comprehensive fractal analysis of the quotations dynamics for six leading companies (Apple Inc., Tesla Inc., Alphabet Inc., The Walt Disney Company, Sony Corporation, Netflix) in this area before and during the COVID-19 pandemic. As a result of the application of the rescaled range analysis (R/S analysis), the presence of the persistence property and long-term memory in the stock quotes dynamics for all companies and its absence in their time series of profitability was confirmed. The application of the method of sequential R/S analysis made it possible to construct fuzzy sets of memory depths for the considered time series and to deepen the analysis of the dynamics due to the quantitative characteristics calculated on their basis. Taking into account the characteristics of memory depth in the dynamics of quotations made it possible to conduct a comparative analysis of the dynamics, both under the influence of the natural crisis situation and in terms of investing in different terms. The peculiarities of the delayed profitability dynamics of quotations for each of the companies are also taken into consideration and compared. The developed recommendations can be used in investment activities in the stock market.
The lack of reversibility during financial crisis and its identification
Authors: Bielinskyi Andrii , Hushko Serhii , Matviychuk Andriy , Serdyuk Oleksandr , Semerikov Serhiy , Soloviev Vladimir
Published: May 2021

The focus of this study to measure the varying irreversibility of stock markets. A fundamental idea of this study is that financial systems are complex and nonlinear systems that are presented to be non-Gaussian fractal and chaotic. Their complexity and different aspects of nonlinear properties, such as time irreversibility, vary over time and for a long-range of scales. Therefore, our work presents approaches to measure the complexity and irreversibility of the time series. To the presented methods we include Guzik’s index, Porta’s index, Costa’s index, based on complex networks measures, Multiscale time irreversibility index and based on permutation patterns measures. Our study presents that the corresponding measures can be used as indicators or indicator-precursors of crisis states in stock markets.
Fuzzy arithmetic in economic research
Authors: Gorbatiuk Kateryna , Zavhorodnia Tetiana , Proskurovych Oksana , Mantalyuk Olha
Published: May 2021

Many tasks in economic research are based on arithmetic calculations of indicators that reflect the state of economic development. The general incompleteness of publicly available data, designed to solve such problems, has led to the emergence of numerous decision support systems based on fuzzy arithmetic. The article presents a study on the approach aimed at integrating fuzzy information about economic indicators into economic models. The definition of arithmetic operations on fuzzy values is given, and the methods of obtaining the resulting fuzzy indicators with the help of some software tools are considered. Analytical and numerical methods of obtaining the resulting indicators in the form of fuzzy numbers are described and analyzed. A direct calculation algorithm for all arithmetic operations is proposed, utilized, and used for the evaluation of resulting indicators. Also, analytical and numerical methods for obtaining fuzzy results are considered in the article, and some of them are proposed for utilization. On the example of economic indicators used in the labor rationing, the results of an evaluation of some indicators for a technological operation in the form of fuzzy numbers were obtained by different methods and compared. The practical recommendations, given in the article, on the use of fuzzy arithmetic in decision support systems outline the directions of further research.
Scientific approach to quantitative measurement and economic processes research in corporate management
Authors: Orlov Oliver , Ryasnykh Yevheniya , Dumanska Kathrin , Savchenko Olena
Published: May 2021

Theoretical and methodological studies of quantitative measurement problems of the outcome economic indicators in corporate management are examined in the article. The author’s vision of scientific exploration as one of the corporate management optimization directions is offered and the basis of such direction as profit margin calculation methodology is presented. It is also suggested to solve problems of quantitative measurement of basic economic processes by using allocation of fixed costs in proportion to profit margin. The methodological basis for evaluating cost-effectiveness with the help of profit margin ratio is developed by the authors. It was revealed that fixed costs are the conditions for doing business and the functional purpose of profit margin is the fixed costs coverage. It is proved that in case of multi-assortment production one of the most effective corporate management approaches to cost estimation and pricing is the profit margin concept provided in this article. One of the advantages of proposed profit margin concept is the availability of special tools revealing the resources that allow covering fixed costs and generating profit with a given level of cost-effectiveness. The obtained results of further adoption can be applied as element of corporate management of manufacturing companies and enterprises in conditions of multi-assortment production and changeable economic environment
Human potential and the system of its commercialization management
Authors: Shkoda Tetiana , Gernego Iuliia , Tepliuk Mariia , Stefanita Anastasia
Published: May 2021

The important factor of business sustainability is human capital. In this regard, there is need to estimate human potential, concerning the effectiveness of its management and commercialization probability. The current research problem lays upon the human potential management and the possibility of its commercialization. The paper aims to provide scientific support on human potential and human capital theories, concerning their connection within the system of a sustainable business development. The research methodology is based on theoretical and methodological approaches of Ukrainian and foreign experts from the last ten years, reflecting human capital and human potential concepts, taking into account business needs. The main part of research highlights the special status of human potential, based on its specific characteristics, including network effects, the ability to convert human potential benefits into significant social and economic effects, hybrid and multiplicative. The paper proposes a new methodological approach on technology for human potential commercialization and management. Human potential commercialization measurement is offered as a new model to assess the significance of human potential and its managerial effectiveness estimation. The study results can be used within programs for sustainable and social business development. More extensive study is required to prove the proposed methodological approach effectiveness within different sectors and branches.
Econometric modelling of bank activities: value-based approach to the problem loans terms’ rescheduling
Authors: Onikiienko Serhii , Dyba Mykhailo , Gernego Iuliia
Published: May 2021

The permanent state of the financial crisis has predictably brought to the forefront such traditional problem of banking as problem loans. This research aims to work out an econometric approach to the solution of the problem of loans terms’ rescheduling. For this purpose, we, firstly, treated credit as a bank’s investment project with cashflows’ chart including initial outflow (principal) and following inflows represented by loan payments. Secondly, we combined the schematic representation of loan’s cashflows with NPV formula accustomed to loan’s cashflows and it allowed to create the econometric models for three types of loan: classic, annuity, serial. Thirdly, for the case when borrower breaks a loan’s payment schedule and it leads to the reduction of loan’s NPV and loss of the wealth of bank’s shareholders, respectively, we outlined special compensative models of cashflows where default in payment is interpreted by the lender as an additional forced loan. We suggested modifying the loan terms (interest rate or effective period of the loan agreement) for the rest of payment periods. Fourthly, we laid the special compensative models of forced loans’ cashflows a top corresponded initial cashflows of loans and this has made it possible to get formulas calculating the modified interest rate and the additional number of loans’ payment periods with the aid of backward calculation. As a result, we developed the econometric models of the loan terms’ modifications based on the prolongation of the initial credit period and the increasing of the initial interest rate.
Economic-mathematical model for complex risk assessment of the enterprise investment project using fuzzy logic
Authors: Chaikovska Inna , Hryhoruk Pavlo , Chaikovskyi Maksym
Published: May 2021

The article proposes an economic-mathematical model for determining a comprehensive risk assessment of the investment project of the enterprise which are based on the approaches of A. Nedosekin. The model is built using fuzzy logic and takes into account the probability of occurrence of each of the identified risks and the level of impact of each of them on the project. The probability of risk is set by experts in the form of points and converted into linguistic terms, and the level of influence of each of them on the project – the ratio of benefits and is determined using Fishburne scales. The proposed Project Risk Model consists of the following stages: formation of initial data using expert opinions; construction of a hierarchical project risk tree; determination of weight coefficients (Fishburne weights) of project risks; selection and description of membership function and linguistic variables; conversion of input data provided by experts from a score scale into linguistic terms; recognition of qualitative input data on a linguistic scale; determination of a complex indicator of investment project risks; interpretation of a complex indicator. The developed model allows managing the risks of the project to maximize the probability of its successful implementation, to compare alternative projects and choose less risky, to minimize the level of unforeseen costs of the project.
Association Between Cardiometabolic Factors and Dizziness in African Americans: The Jackson Heart Study
Authors: Ray Amrita , Spankovich Christopher , Bishop Charles E. , Su Dan , Min Yuan-I , Schweinfurth John M.
Published: May 2021

Abstract Background Balance dysfunction is a complex, disabling health condition that can present with multiple phenotypes and etiologies. Data regarding prevalence, characterization of dizziness, or associated factors is limited, especially in an African American
population. Purpose The aim of the study is to characterize balance dysfunction presentation and prevalence in an African American cohort, and balance dysfunction relationship to cardiometabolic factors. Research Design The study design is descriptive, cross
sectional analysis. Study Sample The study sample consist of N = 1,314, participants in the Jackson Heart Study (JHS). Data Collection and Analysis JHS participants were presented an initial Hearing health screening questionnaire (N = 1,314).
Of these, 317 participants reported dizziness and completed a follow-up Dizziness History Questionnaire. Descriptive analysis was used to compare differences in the cohorts' social-demographic characteristics and cardiometabolic variables to the 997 participants who did not report dizziness
on the initial screening questionnaire. Based on questionnaire responses, participants were grouped into dizziness profiles (orthostatic, migraine, and vestibular) to further examine differences in cardiometabolic markers as related to different profiles of dizziness. Logistical regression
models were adjusted for age, sex, education, reported noise exposure, and hearing sensitivity. Results Participants that reported any dizziness were slightly older and predominantly women. Other significant complaints in the dizzy versus nondizzy cohort included hearing loss,
tinnitus, and a history of noise exposure (p < 0.001). Participants that reported any dizziness had significantly higher prevalence of hypertension, blood pressure medication use, and higher body mass index (BMI). Individuals with symptoms alluding to an orthostatic
or migraine etiology had significant differences in prevalence of hypertension, blood pressure medication use, and BMI (p < 0.001). Alternatively, cardiometabolic variables were not significantly related to the report of dizziness symptoms consistent with vestibular
profiles. Conclusion Dizziness among African Americans is comparable to the general population with regards to age and sex distribution, accordingly to previously published estimates. Participants with dizziness symptoms appear to have significant differences in BMI and blood
pressure regulation, especially with associated orthostatic or migraine type profiles; this relationship does not appear to be conserved in participants who present with vestibular etiology symptoms.
Case Study: Depersonalization and Vestibular Impairment
Authors: Sun Yini , Coltisor Allison , Jacobson Gary P. , Roberts Richard A.
Published: May 2021

Abstract Background We describe herein the case of a patient whose primary complaints were episodic vertigo and “depersonalization,” a sensation of detachment from his own body. Purpose This case study aims to further clinical knowledge
and insight into the clinical evaluation of vertiginous patients with complaints of depersonalization. Research Design This is a case study. Data Collection and Analysis A retrospective chart review of vestibular function testing done on a vertiginous patient
with complaints of depersonalization was performed. Results Vestibular function testing revealed absent cervical and ocular vestibular evoked myogenic potentials on the left side with normal vHIT or video Head Impulse Test, videonystagmography, and rotational chair results,
suggesting peripheral vestibular impairment isolated to the left saccule and utricle. Conclusion The otolith end organ impairment explains the patient's postural deviation to the left side during attempts to ambulate. We recommend that clinicians should be attentive to patient
complaints of depersonalization and perform vestibular evoked myogenic potential testing to determine whether evidence of at least a unilateral peripheral otolith end organ impairment exists.
Analgesic Effectiveness and Improvement in Quality of Life after Using Topical Sevoflurane for an Extremely Painful Anal Fissure
Authors: Cifuentes-Tébar Jesús , Rueda-Martínez Juan Luis , Selva-Sevilla Carmen , Gerónimo-Pardo Manuel
Published: May 2021

Painful anal fissures could be distressing conditions that severely impair the patients' quality of life. The analgesic effectiveness of topical drugs, such as calcium-antagonists and nitrates is quite variable. The inhalational anesthetic sevoflurane is being repurposed as a topical analgesic for painful chronic wounds. We report a pioneer experience treating a painful chronic anal fissure with topical sevoflurane. A young adult male was suffering from an extremely painful chronic anal fissure, which severely affected his quality of life. The topical treatment with nitroglycerine and diltiazem gels failed. The patient agreed to the treatement with topical sevoflurane as an off-label medication, and it produced an immediate, intense, and long-lasting analgesic effect. An intense but rapidly transient burning sensation, as well as persistent but well-tolerated flatulence were the only adverse effects. The quality of life was greatly improved, and the cost of the treatment was affordable. Therefore, the off-label use of topical sevoflurane appears to be an effective alternative for the symptomatic treatment of painful anal fissures.
Polymorphisms of the Vitamin D Receptor Gene in Crohn’s Disease
Authors: Lopes Bhettina Vieira , Ribeiro Vitor Linhares , Marques Larissa de Oliveira Rosa , Sousa Liliane Emilly dos Santos , Leão-Cordeiro Jacqueline Andréia Bernardes , Silva Antonio Márcio Teodoro Cordeiro
Published: May 2021

Introduction Crohn’s disease (CD) and ulcerative colitis (UC) are chronic inflammatory conditions of the gastrointestinal tract. Studies have shown that polymorphisms of the vitamin D receptor (VDR) gene may help elucidate the pathogenesis of CD.

Objectives To analyze the role of VDR gene polymorphisms (ApaI, BsmI, FokI, and TaqI) in the development of CD.

Methods The present study is a systematic review with meta-analysis. a total of 50 articles in English and Portuguese published from 2000 to 2020 were selected from 3 databases. The relationship between CD and the VDR gene was addressed in 16 articles.

Results The TaqI polymorphism was analyzed in 3,689 patients and 4,645 control subjects (odds ratio [OR] = 0.948; 95% confidence interval [95%CI] = 0.851–1.056; p = 0.3467). The ApaI polymorphism was studied in 3,406 patients and 4,415 control subjects (OR = 1,033; 95%CI = 0.854–1.250; p = 0.7356). For FokI polymorphism, there were 2,998 patients and 4,146 control subjects (OR = 0.965; 95%CI = 0.734–1.267; p = 0.7958). Lastly, the BsmI polymorphism was analyzed in 2,981 patients and 4,477 control subjects (OR = 1,272; 95%CI = 0.748–2.161; p = 0.3743).

Conclusion These four VDR gene polymorphisms were not associated with CD. Therefore, further studies with larger samples are required to corroborate or rectify the conclusions from the present meta-analysis.
The Effects of a Single Freeze-Thaw Cycle on Concentrations of Nutritional, Noncommunicable Disease, and Inflammatory Biomarkers in Serum Samples
Authors: Abraham Ransi Ann , Rana Garima , Agrawal Praween K. , Johnston Robert , Sarna Avina , Ramesh Sowmya , Acharya Rajib , Khan Nizamuddin , Porwal Akash , Kurundkar Sucheta Banerjee , Pandey Arvind , Pullakhandam Raghu , Nair Krishnapillai Madhavan , Kumar Geeta Trilok , Sachdev HPS , Kapil Umesh , Deb Sila , Wagt Arjan de , Khera Ajay , Ramakrishnan Lakshmy
Published: May 2021

Background The stability of biological samples is vital for reliable measurements of biomarkers in large-scale survey settings, which may be affected by freeze-thaw procedures. We examined the effect of a single freeze-thaw cycle on 13 nutritional, noncommunicable diseases (NCD), and inflammatory bioanalytes in serum samples.

Method Blood samples were collected from 70 subjects centrifuged after 30 minutes and aliquoted immediately. After a baseline analysis of the analytes, the samples were stored at − 70°C for 1 month and reanalyzed for all the parameters. Mean percentage differences between baseline (fresh blood) and freeze-thaw concentrations were calculated using paired sample t-tests and evaluated according to total allowable error (TEa) limits (desirable bias).

Results Freeze-thaw concentrations differed significantly (p < 0.05) from baseline concentrations for soluble transferrin receptor (sTfR) (− 5.49%), vitamin D (− 12.51%), vitamin B12 (− 3.74%), plasma glucose (1.93%), C-reactive protein (CRP) (3.45%), high-density lipoprotein (HDL) (7.98%), and cholesterol (9.76%), but they were within respective TEa limits. Low-density lipoprotein (LDL) (− 0.67%), creatinine (0.94%), albumin (0.87%), total protein (1.00%), ferritin (− 0.58%), and triglycerides (TAG) (2.82%) concentrations remained stable following the freeze-thaw cycle. In conclusion, single freeze-thaw cycle of the biomarkers in serum/plasma samples after storage at − 70°C for 1 month had minimal effect on stability of the studied analytes, and the changes in concentration were within acceptable limit for all analytes.
Antibody-Mediated Rejection and Lung Transplantation
Authors: Halverson Laura P. , Hachem Ramsey R.
Published: May 2021

Antibody-mediated rejection (AMR) is now a widely recognized form of lung allograft rejection, with mounting evidence for AMR as an important risk factor for the development of chronic lung allograft dysfunction and markedly decreased long-term survival. Despite the recent development of the consensus diagnostic criteria, it remains a challenging diagnosis of exclusion. Furthermore, even after diagnosis, treatment directed at pulmonary AMR has been nearly exclusively derived from practices with other solid-organ transplants and other areas of medicine, such that there is a significant lack of data regarding the efficacy for these in pulmonary AMR. Lastly, outcomes after AMR remain quite poor despite aggressive treatment. In this review, we revisit the history of AMR in lung transplantation, describe our current understanding of its pathophysiology, discuss the use and limitations of the consensus diagnostic criteria, review current treatment strategies, and summarize long-term outcomes. We conclude with a synopsis of our most pressing gaps in knowledge, introduce recommendations for future directions, and highlight promising areas of active research.
Stimuli-responsive twist actuators made from soft elastic composite materials—linking mesoscopic and macroscopic descriptions
Authors: Menzel Andreas M.
Published: May 2021

Very recently, the construction of twist actuators from magnetorheological gels and elastomers has been suggested. These materials consist of magnetizable colloidal particles embedded in a soft elastic polymeric environment. The twist actuation is enabled by a net chirality of the internal particle arrangement. Upon magnetization by a homogeneous external magnetic field, the systems feature an overall torsional deformation around the magnetization direction. Starting from a discrete minimal mesoscopic model setup, we work toward a macroscopic characterization. The two scales are linked by identifying expressions for the macroscopic system parameters as functions of the mesoscopic model parameters. In this way, the observed behavior of a macroscopic system can, in principle, be mapped to and illustratively be understood from an appropriate mesoscopic picture. Our results apply equally well to corresponding soft electrorheological gels and elastomers.
Single-hole couplings in GaAs/AlGaAs double dots probed with transport and EDSR spectroscopy
Authors: Ducatel J. , Padawer-Blatt A. , Bogan A. , Korkusinski M. , Zawadzki P. , Sachrajda A. , Studenikin S. , Tracy L. , Reno J. , Hargett T.
Published: May 2021

We report a detailed study of the tunnel barriers within a single-hole GaAs/AlGaAs double quantum dot device (DQD). For quantum information applications as well as fundamental studies, careful tuning and reliable measurements of the barriers are important requirements. In order to tune a DQD device adequately into the single-hole electric dipole spin resonance regime, one has to employ a variety of techniques to cover the extended range of tunnel couplings. In this work, we demonstrate four separate techniques, based upon charge sensing, quantum transport, time-resolved pulsing, and electron dipole spin resonance spectroscopy to determine the couplings as a function of relevant gate voltages and magnetic field. Measurements were performed under conditions of both symmetric and asymmetric tunnel couplings to the leads. Good agreement was observed between different techniques when measured under the same conditions. The results indicate that even in this relatively simple circuit, the requirement to tune multiple gates and the consequences of real potential profiles result in non-intuitive dependencies of the couplings as a function of the plunger gate voltage and the magnetic field.
Inverse spin-Hall effect in GeSn
Authors: Marchionni A. , Zucchetti C. , Ciccacci F. , Finazzi M. , Funk H. S. , Schwarz D. , Oehme M. , Schulze J. , Bottegoni F.
Published: May 2021

Due to the long spin lifetime and its optical and electrical properties, GeSn is a promising candidate for the integration of spintronics, photonics, and electronics. Here, we investigate the photoinduced inverse spin-Hall effect in a GeSn alloy with 5% Sn concentration. We generate a spin-polarized electron population at the Γ point of the GeSn conduction band by means of optical orientation, and we detect the inverse spin-Hall effect signal coming from the spin-to-charge conversion in GeSn. We study the dependence of the inverse spin-Hall signal on the kinetic energy of the spin-polarized carriers by varying the energy of the impinging photons in the 0.5–1.5 eV range. We rationalize the experimental data within a diffusion model which explicitly accounts for momentum, energy, and spin relaxation of the spin-polarized hot electrons. At high photon energies, when the spin relaxation is mainly driven by phonon scattering, we extract a spin-Hall angle in GeSn which is more than ten times larger than the one of pure Ge. Moreover, the spin–charge interconversion for electrons lying at the Δ valleys of GeSn results to be ≈4.3 times larger than the one for electrons at L valleys.
Numerical modeling of dynamic response and microcracking in shock-loaded polycrystalline transparent ceramic
Authors: Li Tong , Cao Xiuxia , Wang Qian , Li Yuanyuan , He Hongliang , Yu Yin , Li Yongqiang , Jin Xianlong
Published: May 2021

Transparent ceramics are promising materials in the fields of high pressure and high temperature. Based on a lattice-spring simulation method, a novel polycrystalline model for shock-wave compression is established to explore the dynamic response and damage evolution of yttrium aluminum garnet (YAG) under shock loading. The macro-response and micro-fracture process under impact loading can be obtained simultaneously, and a correlation between the macroscopic response and mesoscale damage is shown. The process of crack propagation along a grain boundary and through grain-boundary deflection is observed in the simulation. A change in deformation behavior from intergranular fracture to transgranular fracture in the vicinity of grain boundaries, associated with the transition from an elastic response to a plastic response, is observed, as the shock stress increases from below to above the Hugoniot elastic limit. Computational results demonstrate a clear, exponential attenuation of the elastic precursor wave with the propagation of shock waves. The reasons for the elastic precursor decay and the transition from an elastic response to a plastic response are the stress relaxation and energy dissipation caused by internal transgranular fracture. The polycrystalline model will aid in microstructure design and provide a reference for the development of polycrystalline transparent ceramics in the fields of engineering and scientific research.
Automated source of squeezed vacuum states driven by finite state machine based software
Authors: Nguyen C. , Bawaj M. , Sequino V. , Barsuglia M. , Bazzan M. , Calloni E. , Ciani G. , Conti L. , D’Angelo B. , De Rosa R. , Di Fiore L. , Di Pace S. , Fafone V. , Garaventa B. , Gennai A. , Giacoppo L. , Khan I. , Leonardi M. , Majorana E. , Naticchioni L. , Paoletti F. , Passuello D. , Pegoraro M. , Ricci F. , Rocchi A. , Vardaro M. , Vocca H. , Zendri J.-P. , De Laurentis M. , Sorrentino F.
Published: May 2021

In the last few decades, much effort has been made for the production of squeezed vacuum states in order to reduce quantum noise in the audio-frequency band. This technique has been implemented in all running gravitational-wave interferometric detectors and helped to improve their sensitivity. While the detectors are acquiring data for astrophysical observations, they must be kept in the operating condition, also called “science mode,” that is, a state that requires the highest possible duty-cycle for all the instrumental parts and controls. We report the development of a highly automated setup for the generation of optical squeezed states, where all the required control loops are supervised by a software based on finite state machines; we took special care to grant ease of use, stability of operation, and possibility of auto-recovery. Moreover, the setup has been designed to be compatible with the existing software and hardware infrastructure of the Virgo detector. In this paper, we discuss the optical properties of this squeezing setup, the locking techniques, and the automation algorithms.
Dynamic characterization of 3D printed mechanical metamaterials with tunable elastic properties
Authors: Naghavi Zadeh Mohammad , Alijani Farbod , Chen Xianfeng , Dayyani Iman , Yasaee Mehdi , Mirzaali Mohammad J. , Zadpoor Amir A.
Published: May 2021

Mechanical metamaterials are advanced engineering materials that exhibit unusual properties that cannot be found in nature. The elastic properties (i.e., elastic modulus and Poisson's ratio) of mechanical metamaterials can be tuned by changing the geometry of their fundamental unit cells. This allows for the design of metamaterial lattices with targeted quasi-static properties. However, it is not clear how these freedoms contribute to the dynamic properties of mechanical metamaterials. We, therefore, used experimental modal analysis, numerical simulations, and analytical models to study the dynamic response of meta-structures with different values of the Poisson's ratio. We show that Poisson's ratio strongly affects the damping properties of the considered mechanical metamaterials. In particular, we found an inverse relationship between the damping ratio and the absolute value of the Poisson's ratio of the meta-structures. Our results suggest that architected meta-structures similar to those studied could be tailor-made to improve the dissipative performance of mechanical systems. Geometrical design could play an important role in this regard by providing the possibility to tune the various types of quasi-static and dynamic properties of such mechanical metamaterials.
“Shadow effect” photodetector with linear output voltage vs light intensity
Authors: Hourdakis E. , Kaidatzis A. , Niarchos D.
Published: May 2021

A novel concept for a simple, cost effective, readily integrable with Si electronics and self-powered photodetector is presented. The device consists of a semitransparent Au film deposited on an n-type Si substrate with contacts on the Au layer. The operation of the device relies on the recently demonstrated “shadow effect.” The device is shown to consist of back-to-back Schottky diodes with a built-in parallel resistance caused by the Au layer. Shadowing half of the device area under illumination causes anisotropy in the diodes' behavior creating a measurable open circuit voltage and a short circuit current. The presence of the built-in parallel resistance, along with a large series resistance, causes the open circuit voltage to have a linear term with respect to illumination power, in addition to the logarithmic term normally present in Schottky solar cells. We demonstrate that under certain combinations of series and parallel resistances the open circuit voltage of the device is linear with respect to illumination power for a range between 50 mW/cm2 (0.5 sun) and 0.5 mW/cm2 (0.005 sun). This allows the device to be used as a photodetector operated as a self-powered voltage source, instead of a current source which is the case with most photodetectors operated in the photovoltaic mode.
Elastic and electronically inelastic electron collisions by the thiophene molecule
Authors: Moreira G. M. , Bettega M. H. F. , da Costa R. F.
Published: May 2021

Differential and integral cross sections for elastic and electronically inelastic scattering of electrons by the thiophene molecule were determined by means of the Schwinger multichannel method within the static-exchange plus polarization approximation in the energy range from 3.41 to 50 eV. We investigated the influence of multichannel coupling effects by calculating the cross sections according to different schemes of channel coupling that range from 1 to 61 open channels along with polarization effects, depending on the energy considered. The comparison of these results shows that the inclusion of more channels in the scattering calculations leads to a significant decrease in the magnitude of the cross sections. Present results corresponding to our best level of channel coupling at a given energy, both for elastic and electronically inelastic electron scattering by thiophene, display an overall good agreement with the data available in the literature.
Flow around a diamond-section cylinder at low Reynolds numbers
Authors: Yadav Pavan Kumar , Sourav Kumar , Kumar Deepak , Sen Subhankar
Published: May 2021

The steady separated flow past a diamond cylinder at low Reynolds numbers, Re, is associated with diverse separation topologies not resolved for a circular or square cylinder. The present study, conducted for Re≤150, also uncovers three unique separation topologies for the time-averaged flow. In this regard, the most striking observation is the formation of a small sub-wake around the base of the cylinder at certain Re between 80 and 90. While two of these structures were previously captured by some recent studies, these studies did not investigate their origin or kinematics. In the present study, conducted via stabilized finite-element computations in two-dimensions, these wake topologies are analyzed in detail. For secondary separation, the pressure at the reattachment point on the cylinder rear surface exceeds the pressure at the corresponding separation point located upstream. In a similar manner, for primary separation, the pressure at the wake stagnation point(s) surpasses the one at the separation points. Via direct steady and unsteady computations, the value of the critical Re indicating the onset of vortex-shedding is found to be 41, approximately. At this Re, the flow quantities, such as wake length, drag, and pressure coefficients, obtained from the steady and unsteady computations are found to diverge. The presentation of wake length and drag as a function of base suction establishes that the drag and wake length share an inverse relationship.
Anomalous layer-dependent electronic and piezoelectric properties of 2D GaInS3 nanosheets
Authors: Chen Weizhen , Yin Huabing , Jiang Shujuan , Liu Siyuan , Liu Chang , Wang Bing , Zheng Guang-Ping
Published: May 2021

Two-dimensional (2D) GaInS3 nanosheets are found to exhibit thermal and structural stabilities, good oxidation resistance, and tunable and layer-dependent electronic properties from first-principles calculations. Remarkably, the nanosheets with arbitrary thickness possess robust in-plane piezoelectricity without the odd-even effect commonly observed in other 2D piezoelectric materials, which is attributed to the retention of noncentrosymmetry resulting from their homogeneous and direct stacking patterns. The piezoelectric stress coefficient e113D of the nanosheets is about 0.23 C/m2, almost independent of the numbers of atomic layers of 2D GaInS3. The stability in piezoelectricity and the high carrier mobility of 2D GaInS3 nanosheets could endow them with promising application prospects in nanoelectronic and nanoelectromechanical devices.
Effect of the native oxide on the surface passivation of Si by Al2O3
Authors: Getz Michael N. , Povoli Marco , Monakhov Eduard
Published: May 2021

The effect of the native silicon oxide layer on the passivation properties of Al2O3 on p-type Si surfaces has been investigated. This was done by comparing effective carrier lifetime, surface saturation current density, fixed charge, and density of interface states of samples, where the native oxide was not removed prior to Al2O3 passivation, with samples subjected to a 3 min HF-dip. The sample with the native oxide exhibits excellent surface passivation post-annealing, with a surface saturation current density of 13 fA/cm2 and significantly longer effective lifetime compared to the sample, where the native oxide was removed. Capacitance–voltage measurements of a sample with the native oxide revealed a remarkably low density of interface states (1010 eV−1 cm−2), almost three times lower than a sample where the native oxide was removed prior to Al2O3 deposition. The results indicate that a thin layer of native oxide improves the Al2O3 surface passivation of silicon.
Enhancing the efficiency of semiconducting quantum dot photocatalyzed atom transfer radical polymerization by ligand shell engineering
Authors: Zhu Yifan , Jin Tao , Lian Tianquan , Egap Eilaf
Published: May 2021

Manipulating the ligand shell of semiconducting quantum dots (QDs) has proven to be a promising strategy to enhance their photocatalytic performance for small molecule transformations, such as H2 evolution and CO2 reduction. However, ligand-controlled catalysis for macromolecules, which differ from small molecules in penetrability and charge transfer behavior due to their bulky sizes, still remains undiscovered. Here, we systematically investigate the role of surface ligands in the photocatalytic performance of cadmium selenide (CdSe) QDs in light-induced atom transfer radical polymerization (ATRP) by using thiol-based ligands with various polarities and chain lengths. A highly enhanced polymerization efficiency was observed when 3-mercapto propionic acid (MPA), a short-chain and polar ligand, was used to modify the CdSe QDs’ surface, achieving high chain-end fidelity, good temporal control, and a dispersity of 1.18, while also tolerating a wide-range of functional monomers ranging from acrylates to methacrylates and fluorinated monomers. Transient absorption spectroscopy and time-resolved photoluminescence studies reveal interesting mechanistic details of electron and hole transfers from the excited QDs to the initiators and 3-MPA capping ligands, respectively, providing key mechanistic insight of these ligand controlled and QD photocatalyzed ATRP processes. The thiolate ligands were found to serve as an efficient hole acceptor for QDs, which facilitates the formation of a charge-separated state, followed by electron transfer from the conduction band edge to initiators and ultimately suppressing charge recombination within the QD.
Polar Kerr effect and perpendicular magnetic anisotropy in Fabry–Pérot cavity containing CoPt/AZO magneto-optical interference layer
Authors: Yamane H. , Yasukawa Y. , Kobayashi M.
Published: May 2021

We investigate the magneto-optical (MO) polar Kerr enhancement of Fabry–Pérot cavities with perpendicular magnetic anisotropy for chemical and biological sensing applications. The MO cavities consist of stacked films with a half-mirrored surface layer, a dielectric interference layer, a total-reflection mirror, and a magnetic metal layer. Co80Pt20 and Al-doped ZnO (AZO) thin films were utilized as the magnetic and interference layers, respectively. The cavities produce two types of MO enhancement depending on the thickness of the magnetic layer. The sample with a thick magnetic layer as a total-reflection mirror generates a single peak in the polar Kerr spectrum. Contrarily, inserting a several-nanometer-thick CoPt layer into the AZO layer produces a resonant-type spectrum. Although both samples generate large MO enhancement factors (>50), the magnetic properties significantly differ. The AZO/CoPt/AZO interference layer controls the crystalline and interface conditions and produces a square-shaped out-of-plane hysteresis loop with a large Kerr rotation angle. Moreover, the use of an ultrathin CoPt film significantly reduces the saturation magnetization field. Thus, Fabry–Pérot cavities with a CoPt/AZO interference layer may serve as high-sensitivity, low-energy-consumption sensor elements.
Enhanced light-matter interactions at photonic magic-angle topological transitions
Authors: Hu Guangwei , Zheng Chunqi , Ni Jincheng , Qiu Cheng-Wei , Alù Andrea
Published: May 2021

In analogy to Lifshitz transitions in electronic systems, topological transitions have recently attracted widespread attention in photonic metamaterials, metasurfaces, and two-dimensional materials, enabling exotic regimes for light-matter interactions. Here, we discuss and study enhanced photonic local density of states in twisted hyperbolic bilayers, enabled by topological transitions emerging at specific twist angles. Our results enhance the understanding of nanoscale light-matter interactions in stacked optical materials as they are rotated with respect to each other in the context of twistronics and suggest emerging applications of these concepts for photonics, including for the manipulation of radiative heat transfer and the control and harvesting of light at the nanoscale.
Molecular mechanism underlying transport and allosteric inhibition of bicarbonate transporter SbtA
Authors: Fang Sunzhenhe , Huang Xiaowei , Zhang Xue , Zhang Minhua , Hao Yahui , Guo Hui , Liu Lu-Ning , Yu Fang , Zhang Peng
Published: May 2021

Significance

SbtA is a sodium-dependent, high-affinity bicarbonate transporter in the cyanobacterial CO
2
-concentrating mechanism (CCM). The transport activity of SbtA is regulated by SbtB, which is additionally influenced by adenyl nucleotides. We determined the three-dimensional structures of SbtA in complex with SbtB in two different conformations: A model summarizing the molecular mechanism of transport and allosteric inhibition of SbtA was established based on structural and biochemical data. The transport and regulatory mechanism revealed by our study represents a valuable case to investigate allosteric regulation of membrane transporters and, more importantly, will benefit plant photosynthesis improvement using the CCM system.
Bactrocera cucurbitae (melon fly).
Authors: Bakri Abdeljelil
Published: May 2021

Considered native to India, B. cucurbitae, the melon fly, is now found in more than 40 countries. The potential risk of its introduction to a new area is facilitated by an increase in international tourism and trade, and is influenced by changes in climate and land use. After introduction, it can easily disperse due to its high reproductive potential, high biotic potential (short life cycle of 3-5 weeks, up to 10 generations of offspring per year), and a rapid dispersal ability. The economic impacts of this species result primarily from the loss of export markets and the costly requirement of quarantine restrictions and eradication measures. Furthermore, its establishment has a serious impact on the environment following the initiation of chemical and/or biological control programmes. B. cucurbitae is of quarantine significance to EPPO (European and Mediterranean Plant Protection Organization), APPPC (Asia and Pacific Plant Protection Commission), COSAV (Comité de Sanidad Vegetal del Cono Sur), CPPC (Caribbean Plant Protection Commission), and OIRSA (Organismo Internacional Regional de Sanidad Agropecuaria) countries.
Thermoacoustic assessment of hematocrit changes in human forearms*
Authors: Wang Xue , Zhao Rui , Peng Yi-Tong , Chi Zi-Hui , Zheng Zhu , Li En , Huang Lin , Jiang Hua-Bei
Published: May 2021

Abnormal hematocrit (Hct) is associated with an increased risk of pre-hypertension and all-cause death in general population, and people with a high Hct value are susceptible to arterial cardiovascular disease and venous thromboembolism. In this study, we report for the first time on the ability of thermoacoustic imaging (TAI) for in vivo evaluating Hct changes in human forearms. In vitro blood samples with different Hct values from healthy volunteers (n = 3) were prepared after centrifugation. TAI was performed using these samples in comparison with the direct measurements of conductivity. In vivo TAI was conducted in the forearm of healthy volunteers (n = 7) where Hct changes were produced through a vascular occlusion stimulation over a period of time. The results of in vitro blood samples obtained from the 3 healthy subjects show that the thermoacoustic (TA) signals changes due to the variation of blood conductivity are closely related to the changes in Hct. In addition, the in vivo TA signals obtained from the 7 healthy subjects consistently increase in the artery/muscle and decrease in the vein during venous or arterial occlusion because of the changed Hct value in their forearms. These findings suggest that TAI has the potential to become a new tool for monitoring Hct changes for a variety of pre-clinical and clinical applications.