bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical study of a desaturation process by air injection in sandy soil
Authors: Sepulveda-Cano Sebastian , Garcia-Aristizabal Edwin F. , Vega-Posada Carlos A.
Published: April 2021

This work aims to numerically study the desaturation process in a coarse-grained sandy deposit by means of air injection. It is well-known that the soil cyclic strength to liquefaction of a saturated, sandy deposit is positively affected by the presence of gas in the void space in either a dissolved or a free form. A numerical study is performed to investigate some of the factors affecting the desaturation advance and controlling the soil desaturation process by air injection. Among these factors are: a) soil-water characteristic curve and intrinsic permeability (hydraulic parameters), b) injection time, and c) standard approach to two injection wells placement. Only the standard mechanisms of biphasic flow are investigated (i.e., incompressible and isothermal biphasic flow in an isotropic homogeneous porous media with capillary effects).
Non-isothermal moisture migration in a GCL composite liner system
Authors: Tincopa Mayu , Carnero-Guzman Gonzalo
Published: April 2021

Geosynthetic Clay liners (GCLs) are used extensively in waste management facilities as part of hydraulic and gas barriers since the bentonite, active component of GCLs, possesses a low conductivity when well hydrated. GCL hydration occurs in the unsaturated regime following the water retention curve of the GCL and subsoil (wetting and drying path of the WRC of the GCL and subsoil, respectively). Moreover, the GCL hydration is controlled/governed by factors such as applied stress condition, subsoil characteristics, and weather condition (temperature). This paper numerically studied the influence of temperature in the GCL hydration. The models were conducted using Vadose/W and simulations were calibrated with experimental results and further practical scenarios were then predicted. Five temperature conditions that resemble average and extreme weather were used (5°C, 10°C, 20°C, 50°C, 70°C, respectively). Results indicate that temperature influence the GCL hydration rate and the final water content achievable, which affect the final performance of the GCL.
Plot test in a 50-year abandoned mine tailings dam
Authors: Libardi Lucas Garino , Oldecop Luciano Agustín
Published: April 2021

Knowing the evolution of water content in a tailings dam is essential when analysing its stability. The case study is a small tailings dam abandoned more than 50 years ago, located in the Andes region of San Juan province, Argentina, where the climate is arid. This paper presents the results obtained in a plot test to study the interaction of tailings with the atmosphere, and to explain the reasons that generate internal zones in the dams with surprisingly high degrees of saturation, despite the strong water deficit of the site. The plot was hydraulically isolated on the four lateral faces where ten capacitive sensors were installed at different depths (volumetric moisture, matrix suction and temperature). At the beginning of the test, a major rainfall event was simulated with a sprinkler irrigation system. The plot was then allowed to interact freely with the atmosphere for an additional period of one and a half years. The records obtained suggest that the stratigraphy of the hydraulically deposited tailings has a preponderant influence on the interaction with the atmosphere. Heterogeneous flow phenomena and multiple capillary barriers during the infiltration and evaporation processes, respectively, appear to control the long-term moisture state of the tailings dam.
Humanization of the Siberian prison and power: lessons from the imperial period of Russian history
Authors: Naumenko Olga , Naumenko Evgeny , Tkacheva Tatiana , Blashkova Lyudmila , Salmina Svetlana
Published: April 2021

In 2020, the implementation of the 10-year concept for the development of the penal system, aimed at the humanization of prisoner welfare, was ended. The article examines the political result of a closely related reform – the gradual humanization of the Siberian prison in the 19th - early 20th century. The authors believe that the outcome of the prison reform in Russia, in contrast to Europe, was characterized by a weakening of the state power. Given the poverty of the Russian people, their disenfranchisement and unemployment, the material conditions in the reformed prisons were often better than those of law-abiding citizens at liberty. On the one hand, this hindered the reduction of crime rates, but, on the other hand, caused misunderstanding in Russian society, exacerbated the sense of injustice and projected it onto the state authorities.
The role of a foreign accent in the social and personal identification of a speaker
Authors: Popova Marianna
Published: April 2021

The intensification of migration processes in Europe necessitates studying the foreign accent as a means of social and personal diagnostics within multicultural communities in the light of the increased number of cases of the “accent-based” discrimination, since the foreign accent is perceived negatively by native speakers and causes less confidence in a speaker. Studies carried out in recent decades suggest that external signs are gradually losing their leading role in social identification, giving way to more reliable and objective means – pronunciation characteristics, since they are practically impossible to control. For this reason, an experimental phonetic research was carried out on the material of the German language in order to identify the nature of the influence of accentedness on the social identification of Russian-speaking immigrants from the position of German native speakers, as well as to determine the acceptation limits of accentedness degree of Russian-speaking bilinguals. With regard to the results of the study, it was found that a strong accent negatively affects the overall assessment of an individual in terms of the educational level, income and success of a speaker, while in terms of personal characteristics there is no pronounced negative attitude towards people speaking with a Russian accent, regardless of the degree of accentedness.
Research of the factors and conditions for development of the digital economy in Russia
Authors: Ilchenko S.M.
Published: April 2021

The basis of the study is the compilation and analysis of works by domestic and foreign economists, study of the information from official websites of government bodies, methods of analysis, comparison and generalization, and mathematical modeling. Results and conclusions: in order to develop the effective approaches and directions for the research program for development and transformation of the digital economy in Russia, in addition to global processes and digitalization trends at the regional level, along with politics, economic environment, macro-processes, it is important to take into account the sum of factors of the ecosystem of the digital economy as a new economic order: economic, demographic, scientific and technical, geo-potential, state and legal factor. The scientific novelty of the study is reflected in the proposed understanding of the term “digital ecosystem” for solving the above set problem using interdisciplinary approach.
Transformation of the Ethics of Public Authority in the context of changing paradigms of public administration
Authors: Denisov Yuri , Nemtsova Natalia
Published: April 2021

The research is devoted to the identification and analysis of the vectors of the evolution of the modern system of ethics of public authority. The first of them arose within the framework of the Weber paradigm, which consists in the codification of the norms of ethics of public authorities, which is largely anti-corruption. The second vector is associated with the introduction of the New Public Management paradigm and consists in reorienting the ethics of public authority and the personality of a civil servant to the service-management concept of public administration. The third vector emerged in line with the "Good Governance" paradigm. It focuses the ethical system of public authority on cooperation with all participants of the socio-political field and inclusiveness. In the context of the digitalization of the socio-political space, the Good Governance paradigm has begun a rapid evolution into the Digital Era Governance paradigm. Under these conditions, the public authorities faced an urgent need to modernize their ethical system, the need for its dynamic adaptation to rapidly changing technological realities and faced the challenges of a new ethics.
Implementing the personnel potential of the public civil service of a constituent entity of the Russian Federation in the context of the introduction of a comprehensive assessment of personnel
Authors: Alekseeva Tatiana , Bezvikonnaya Elena , Bogdashin Aleksander , Portnyagina Elena
Published: April 2021

Under the conditions of administrative reform, implemented within the ideology of public management, the issues of assessing the effectiveness of the institution of public service turn out to be one of the systemic. The priority established by the state in favor of the introduction of key performance indicators (KPIs) in the professional evaluation of civil servants requires thinking about its impact on the formation of human resources capacity. The purpose of the article is to evaluate the mechanisms of implementation of a comprehensive assessment of the professional activities of civil servants in the constituent entity of the Russian Federation (based on the materials of the Omsk region). The methodological basis of the study is a systematic methodological approach and methods for assessing the personnel potential of public service. The novelty of the work lies in the involvement of the source base of the Omsk region as one of the typical regions of the Siberian Federal District. The results of the study are of particular value for the summarization of the practice of implementing the mechanism of comprehensive professional evaluation of civil servants in the constituent entities of the Russian Federation.
Innovative development of socio-technical systems
Authors: Moiseeva Tatiana , Myatishkin Yuri
Published: April 2021

Modern management of socio-technical systems is based on the principles of the classical ideal bureaucracy of Max Weber, formed many decades ago. Among the historically inherited problems of modern management, corresponding to the traditional development of socio-technical systems, the decisive factor is the bias towards the formalization of management. A person with untapped potential is pushed out of the management system. The subject is depersonalized and placed on a par with other elements of the model. This approach underlies the development of socio-technical systems, which can be called traditional. Innovative development requires the use of new management methods to unleash the potential of people. Among the subject-oriented approaches to management, we should underline the theory of intersubjective management, proposed by V.A. Vittikh. It could complement traditional management.
A model for commercializing the outcomes of innovation/research activity in universities
Authors: Bogovin Vladislav , Vidishcheva Evgeniya
Published: April 2021

Innovation activity is central to economic modernization. Despite the fact that Russia possesses serious scientific/technical potential, it has fallen significantly behind industrial countries in getting innovative solutions to an open commercial market. The nation has had difficulties in commercializing innovative output, which has kept it from achieving the economic returns that it deserves. The commercialization of R&D outcomes is indispensable to the strategic development of any organization. The insufficiently effective realization of innovation potential in Russia is largely due to the detachedness of innovation activity in higher education institutions from practice and a lack of interest from business – a key agent of innovation commercialization. The research reported in this paper focuses on the scientific/theoretical and practical/applied foundations of the process of commercializing the outcomes of innovation activity in higher education institutions. It has helped establish and gain an insight into some of the key issues in the area. The paper makes a case for the possibility of enhancing this process via a special model for commercializing the outcomes of innovation activity in higher education institutions.
Personnel imbalance and ways to overcome it in the healthcare sector
Authors: Chernenko Eleonora , Lebedeva Inna
Published: April 2021

The National Healthcare Project, which has been implemented in our country since 2019, includes eight federal projects aimed at developing individual elements of the industry. The federal project "Providing medical organizations of the healthcare system with qualified personnel" is the connecting link of all eight projects. It involves the elimination of the shortage of doctors and nurses in polyclinics, the staffing of medical workers by 95% and an increase in the number of doctors by 10% by the end of 2024. Without a sufficient number of specialists in the industry, its effective work is impossible. The surge in the incidence of coronavirus infection has become another challenge for the healthcare industry and exacerbated the problem of staff shortages. To solve the personnel problem, first of all, it is necessary to understand the reasons for the imbalance, to understand the incentives of young people who have just come to receive education and in the labor motives and doctors already working in the industry, to know the reasons that force them to leave the profession. The article presents the results of a study of factors-motivators of medical students, as well as medical workers.
An analysis of correspondence of a training of specialists in a sphere of standardization and certification to the requirements of RF regions
Authors: Vasilega Dmitriy , Zyryanova Alena
Published: April 2021

Nowadays standardization has a meaningful role for the modern society. But as all existing spheres, the standardization has a scope of problems. The most significant and important problem is a problem of the training of specialists in a sphere of standardization and metrology. This problem is expressed in discrepancy of quality and quantity of labor force to demands of the job market, consequently both population of a region and the state in general have great losses. We conducted a correlative analysis of a bonding force between a gross regional product of federal districts of RF and quantity of universities which train specialists in the field of study of 27.03.01 “Standardization and metrology” and also centres of standardization, metrology and tests (CSMT) and private test laboratories.
Anti-crisis mechanisms for solving the problems of agriculture development in the modern context
Authors: Kundius V.A. , Sergienko O.V.
Published: April 2021

The article concentrates on the problems of the formation and development of agriculture in Russia in the event of a crisis caused by the pandemic, and provides brief characteristics of the core business activities in this direction. The features of the agrarian crisis, as one of the forms of economic recession, which are provoked by economic crises, and are also associated with business cycle fluctuations, are revealed. Furthermore, the main threats to the agricultural sector, the level of development of Russian agriculture at the present time are considered. A SWOT analysis of the environment-related activities of agricultural producers is presented, and the prospects for the development of the agro-industrial complex in a shifting trajectory from subsidized financing and debt restructuring of the agricultural sector to high technologies are considered. The authors state that modern society is developing in a cyclical spiral, in search of new models and new approaches to the managerial economics in agricultural production. The need for strategic anti-crisis intervention in the agro-industrial complex is determined by predicted patterns inherent in critical phases in the evolution of the system.
Students' organism state in conditions of distance learning
Authors: Dragich O.A. , Sidorova K.A. , Yurina T.A. , Plotnikova E.V. , Akhshiyatova N.I.
Published: April 2021

In the course of distance learning, the student is located remotely from his teacher, as well as from the educational institutions themselves. Such education is carried out mostly with the use of technologies for studying. Online learning contributes to improving the education quality due to the active implementation of the worldwide educational resources and a large share of independent work. A manifestation of negative impact of such education is stress caused not only by worries about coronavirus situation, but also by changes in the education field. Distance learning implies strict self-control, independence and consciousness of the student, ability to restrain their emotional states.
Topical directions of didactics development in the XXI century
Authors: Ivanova Elena , Klarin Mikhail , Osmolovskaya Irina
Published: April 2021

The paper analyzes challenges of modern society affecting changes in education that determines the current directions of didactics development. The authors establish that in didactics there are: 1) expansion of the set of objects studied by didactics (the study of general secondary education is supplemented by the study of higher, corporate, family education, education of students with different educational needs), consideration of the learning process in the context of digitalization; 2) the development of methodological approaches to didactic research (activation of empirical research, an increase in the role of research methods of the humanities in didactics, setting the task of developing evidence-based learning research); 3) activation of interdisciplinary research in education (consideration of didactic objects from the standpoint of related sciences - didactics, psychology, cognitive science, sociology). The paper consideres conceptual provisions in the development of didactics of higher education.
Legal protection of employees of educational program service in the context of training using distance technologies
Authors: Sergeenko Yulia , Scherbakova Olga , Kombarova Elena , Rybkina Marina , Kolomeytseva Tatyana
Published: April 2021

The authors of the paper have developed and proposed the structure of the educational program service (hereinafter referred to as the “EPS”) during the transition of the educational process in 2019-2020 to a new level (training is currently taking place both offline and online). The use of this system implies an increase in labor protection for EPS employees, the quality of the educational process in educational institutions of higher education (hereinafter referred to as the “Educational organizations”), simplification of work for the teaching staff, which should be consolidated at the state level. The necessity of using this structure in educational institutions of higher education has been substantiated; the concepts and principles of EPS work have been proposed. The authors of the study propose to provide for this structure both at the federal and at the local levels, thereby carrying out labor and legal protection of EPS employees.
IT technology in the management of the modern educational organization: implementation strategies and development
Authors: Gorbunova Nataliya , Ponomareva Elena
Published: April 2021

The article discusses the specifics of the management of a modern educational organization through the application of various innovative technologies. Thus it concentrates on IT technology, which represent a special stage of technological progress. The organizational and management activities by applying such technologies in the implementation and development process of these technologies for the educational and morale building activities of the modern teacher are being considered. Strategies for introducing and developing IT technology into the modern educational process are defined. The research resulted in comprehensive analytical conclusion, based on a survey aimed at future teachers, managers in education as well as students of different fields of training. In the course of the research, there was a survey conducted on "The application of IT technology in the modern educational process: factors of influence and effect" among students and graduates of the Federal Autonomous Education Institution of Higher Education "Crimean Federal University named after V.I. Vernadskiy". Respondents were 265 students and 120 teachers.
Social and political processes in the context of contemporary communication technologies
Authors: Saryglar Artysh , Gonchar Oleg , Chirun Sergey
Published: April 2021

The article is devoted to the analysis of social and political processes in the aspect of modern technologies of political communication. In particular, the issue of stability of institutional development is touched upon in the context of innovative socio-political processes associated with the introduction of information digital technologies into public policy. The authors investigate current examples of the impact of these technologies on Russian political practices and suggest current areas of work with Internet communication technologies. The authors consider the information society as a global space for political communications, drawing their attention to new potential and real challenges and threats associated with the use of digital information arrays.
Operation nach Nuss – minimalinvasives Verfahren zur Korrektur der Trichterbrust
Authors: Mastorakis Avraam , Petrella Alessandro
Published: April 2021

Um eine Trichterbrust (Pectus Excavatum) zu behandeln, gibt es mehrere OP-Verfahren. Wir stellen Ihnen das vermutlich schonendste vor: die minimalinvasive Methode nach Nuss, die auch bei jüngeren Kindern angewendet werden kann.
Endoscopic resection using an over-the-scope clip for duodenal neuroendocrine tumors
Authors: Tashima Tomoaki , Ryozawa Shomei , Tanisaka Yuki , Fujita Akashi , Miyaguchi Kazuya , Ogawa Tomoya , Mizuide Masafumi , Mashimo Yumi , Kawasaki Tomonori , Yasuda Masami
Published: April 2021

Background and study aims Endoscopic resection of duodenal neuroendocrine tumors (DNETs) remains controversial, and its indications are still unclear. This study aimed to evaluate short-term outcomes of a newly developed endoscopic muscularis resection (EMR) method that utilizes an over-the-scope clip (OTSC), termed EMRO, for treating DNETs.

Patients and methods In total, 13 consecutive patients with 14 small (≤ 10 mm) DNETs who underwent EMRO from September 2017 to March 2020 were retrospectively enrolled. EMRO was performed by a single experienced endoscopist. Patients’ characteristics and treatment outcomes were assessed.

Results The En bloc and R0 resection rates were 100 % (14/14) and 92.9 % (13/14), respectively. The median pathological resected specimen size was 10 mm, with a median pathological resected tumor size of 6 mm. During the EMRO procedure, there was no occurrence of misplacement of the OTSC to the target lesion. With respect to the pathological resection depth, nine cases (64.3 %) and five cases (35.7 %) were categorized as deep submucosal resection and muscularis resection, respectively, whereas no case was categorized as full-thickness resection. There were no intraoperative or delayed perforations. However, delayed bleeding occurred in two cases. At a median follow-up of 12 months (range 7–36) after EMRO, there was no incidence of local recurrence. At the first follow-up endoscopy performed at 6 months after EMRO, the OTSC was retained in place in two of 14 DNETs (14.3 %).

Conclusions EMRO can be performed safely, by an experienced endoscopist, for small (≤ 10 mm) DNETs.
Radiofrequency ablation for intraductal extension of ampullary adenomatous lesions: proposal for a standardized protocol
Authors: Tringali Andrea , Matteo Maria Valeria , Orlandini Beatrice , Barbaro Federico , Perri Vincenzo , Zhang Qianqian , Ricci Riccardo , Costamagna Guido
Published: April 2021

Background and study aims Intraductal extension of ampullary adenoma represents a challenging endoscopic issue. Intraductal radiofrequency ablation (RFA) has been recently suggested, but evidence and standardization of this technique are still lacking. This study aimed to provide a long-term evaluation of clinical efficacy and safety of intraductal RFA ablation with a standardized algorithm of treatment.

Patients and methods Data were prospectively collected from consecutive patients with intraductal extension of adenomatous ampullary lesions from January 2016 to November 2018. Endpoints of the study were clinical success evaluated on histology results at the last follow-up, technical success, and adverse events assessment.

Results Nine patients with intraductal (biliary ± pancreatic) extension of ampullary adenomas were treated with RFA during the study period. Histology on the papillectomy specimen confirmed intraductal involvement with low-grade dysplasia (LGD) in five cases (56 %), high-grade dysplasia (HGD) in three (33 %), and HGD with intramucosal adenocarcinoma in one patient (11 %). Additional argon plasma coagulation to ablate the adenoma on the duodenal mucosa was applied in five patients (56 %). Technical success was 100 %. One patient (11 %) with failed pancreatic stenting, developing acute pancreatitis after RFA, recovered with medical therapy. After a median follow-up of 21 months (IQR 20–31), six patients (67 %) achieved clinical success being free of recurrence, whereas one was diagnosed with persistence of adenocarcinoma, one with recurrent HGD, and one with recurrent LGD.

Conclusions In our experience, intraductal RFA achieved acceptable results after a 2-year follow-up. Further studies are required to confirm our results and to select those patients most likely to respond.
Zwangsstörungen im Kindes- und Jugendalter
Authors: Roessner Veit , Uhlmann Anne
Published: April 2021

Zwangsstörungen sind durch Zwangsgedanken und/oder Zwangshandlungen charakterisiert. Als Zwangsgedanken werden wiederkehrende Gedanken, Ideen und Impulse bezeichnet, die auch aufgrund ihres Inhaltes unangenehme Emotionen verursachen. Zwangshandlungen sind wiederholte, beabsichtigte Verhaltensweisen, die meist auf einen Zwangsgedanken hin, oft in immer gleicher Weise ausgeführt werden, meist um scheinbares Unheil zu verhindern oder unangenehme Emotionen zu reduzieren. Zwangsstörungen weisen ein erhebliches Chronifizierungsrisiko auf. Häufig treten komorbide Angst-, Tic-, Ess-, Aufmerksamkeits-, depressive und Störungen der Impulskontrolle auf. An der Entstehung und Aufrechterhaltung einer Zwangsstörung sind biologische und psychosoziale Faktoren beteiligt. Als wirksame Behandlung von Zwangsstörungen im Kindes- und Jugendalter haben sich kognitiv-verhaltenstherapeutische Ansätze, wie Interventionen und Expositionsbehandlung mit Reaktionsmanagement ergänzt durch Psychoedukation etabliert. Erst nach deren Erfolglosigkeit bzw. in schweren Fällen ist eine pharmakologische Behandlung mit selektiven Serotonin-Wiederaufnahmehemmern (SSRI) indiziert.
Emotionale und depressive Störungen bei Kindern und Jugendlichen
Authors: Lincke Lena , Kölch Michael
Published: April 2021

Bei depressiven Störungen im Kindes- und Jugendalter handelt es sich um ernstzunehmende Erkrankungen. Sie treten häufig gemeinsam mit anderen psychischen Störungen auf, neigen zur Chronifizierung und können die Funktionsfähigkeit und Teilhabechancen der Betroffenen langfristig beeinträchtigen. Alterstypische Symptome, wie eine gereizte Stimmung oder anhaltende Lustlosigkeit werden häufig nicht erkannt, da sie sich von den aus dem Erwachsenenalter bekannten Symptomen unterscheiden. Gerade in der Pubertät können depressive Symptome zudem schwer von alterstypischem Verhalten abzugrenzen sein. Das Auftreten depressiver Störungen lässt sich nicht auf eine einzige Ursache zurückführen. Neben neurobiologischen Faktoren tragen insbesondere schwere, belastende Lebensereignisse zu einem erhöhten Risiko bei, im Kindes- und Jugendalter an einer Depression zu erkranken. Die Behandlung depressiver Störungen orientiert sich am Schweregrad der Erkrankung und umfasst zumeist verhaltenstherapeutische Interventionen, teils in Kombination mit einer Medikation. Ergänzende Behandlungsansätze, wie Lichttherapie oder spezifische Ernährungszusätze werden auf ihre Wirksamkeit überprüft.
Solvent-Free Conjugated Polymer Fluids with Optical Functions
Authors: Shinohara Akira , Guo Zhenfeng , Pan Chengjun , Nakanishi Takashi
Published: April 2021

Solvent-free fluidic materials possessing optoelectronic functions are expected to be major components in soft electronics applications. Conjugated polymers are promising targets for this purpose and their design approaches are classified into three types with respect to their structure: conjugation breaking (Type I), copolymerization with flexible polymers (Type II), and side chain engineering (Type III). In this short review, we highlight several early attempts to produce Type III conjugated polymers. We also present fully characterized Type III fluids recently developed by our group, with a brief summary of the structure–property relationship and fluidity-oriented functions.

Introduction

1 Polymer Design

1.1 Fluidity of Polymeric Materials

1.2 Type III CPs with T g < 25 °C

1.3 Fluidification of Polyfluorenes

1.4 Effect of Side Chain Length

2 Fluidity-Oriented Functions

2.1 Mechanofluorochromism

2.2 Consistent Luminescence in Wide Range of Elastic Moduli

2.3 Prediction of Viscoelasticity

Conclusions and Outlook
Yield degradation due to laser drive asymmetry in D3He backlit proton radiography experiments at OMEGA
Authors: Johnson T. M. , Birkel A. , Ramirez H. E. , Sutcliffe G. D. , Adrian P. J. , Glebov V. Yu. , Sio H. , Johnson M. Gatu , Frenje J. A. , Petrasso R. D. , Li C. K.
Published: April 2021

Mono-energetic proton radiography is a vital diagnostic for numerous high-energy-density-physics, inertial-confinement-fusion, and laboratory-astrophysics experiments at OMEGA. With a large number of campaigns executing hundreds of shots, general trends in D3He backlighter performance are statistically observed. Each experimental configuration uses a different number of beams and drive symmetry, causing the backlighter to perform differently. Here, we analyze the impact of these variables on the overall performance of the D3He backlighter for proton-radiography studies. This study finds that increasing laser drive asymmetry can degrade the performance of the D3He backlighter. The results of this study can be used to help experimental designs that use proton radiography.
A grid-free approach for simulating sweep and cyclic voltammetry
Authors: Coffman Alec J. , Lu Jianfeng , Subotnik Joseph E.
Published: April 2021

We present a computational approach to simulate linear sweep and cyclic voltammetry experiments that does not require a discretized grid in space to quantify diffusion. By using a Green’s function solution coupled to a standard implicit ordinary differential equation solver, we are able to simulate current and redox species concentrations using only a small grid in time. As a result, where benchmarking is possible, we find that the current method is faster than (and quantitatively identical to) established techniques. The present algorithm should help open the door for studying adsorption effects in inner sphere electrochemistry.
Repulsive and attractive depletion forces mediated by nonadsorbing polyelectrolytes in the Donnan limit
Authors: Landman Jasper , Schelling Max P. M. , Tuinier Remco , Vis Mark
Published: April 2021

In mixtures of colloids and nonadsorbing polyelectrolytes, a Donnan potential arises across the region between surfaces that are depleted of the polyelectrolyte and the rest of the system. This Donnan potential tends to shift the polyelectrolyte density profile toward the colloidal surface and leads to the local accumulation of polyelectrolytes. We derive a zero-field theory for the disjoining pressure between two parallel flat plates. The polyelectrolyte is allowed to enter the confined interplate region at the cost of a conformational free energy penalty. The resulting disjoining pressure shows a crossover to a repulsive regime when the interplate separation gets smaller than the size of the polyelectrolyte chain, followed by an attractive part. We find a quantitative match between the model and self-consistent field computations that take into account the full Poisson–Boltzmann electrostatics.
Optimization of connection architectures and mass distributions for metamaterials with multiple resonators
Authors: Wei Wenming , Ren Shuwei , Chronopoulos Dimitrios , Meng Han
Published: April 2021

Metamaterials with multiple resonators have been widely investigated for the purpose of generating multiple stop bands or broadening the attenuation bandwidth. The multiple resonators could be connected end to end in a line, namely, in-series connection, or connected individually to the host structures, namely, in-parallel connection. This paper investigates the influence of the resonator connection methodology on the frequency response functions of metamaterial beams with multiple resonators and exhibits an approach for optimizing their resonator distribution over the structure. The receptance functions of metamaterial beams with various resonator connection architectures are calculated by a transfer matrix model, which is verified through finite element model results. It is demonstrated that resonator interconnection architectures have a great impact on the global dynamic properties of metamaterials. An optimization strategy is subsequently proposed to find out the optimal resonator connection architectures and mass distributions that could minimize the maximal receptance functions in targeted single and multiple frequency ranges. The objective functions within single targeted frequency ranges are solved by the adoption of the genetic algorithm method. The weighted sum method is used to gain an optimal solution for multi-frequency range optimization. The metamaterial beams with optimal resonator connection methods and mass distributions demonstrate greatly enhanced vibration attenuation at frequencies of interest compared with other beams. The work is expected to provide the necessary theoretical basis and incentive for future researchers working on the design of metamaterials with extended, tuned, and optimized stop bands.
Confinement effects on the solvation structure of solvated alkaline metal cations in a single-digit 1T-MoS2 nanochannel: A first-principles study
Authors: Zhan Cheng , Sun Yangyunli , Aydin Fikret , Wang Y. Morris , Pham Tuan Anh
Published: April 2021

Confinement plays an important role in determining ion transport in porous materials, which, in turn, may influence the performance of many energy storage and desalination devices. In this work, we combined density functional theory (DFT) with an implicit solvation model and ab initio molecular dynamics (AIMD) to investigate the effects of nanoconfinement on several solvated alkaline metal cations in a single-digit 1T-MoS2 nanochannel. Our DFT calculations with a solvation model indicated that cations with stronger hydration energy introduce a higher number of co-intercalated water molecules into the channel, consistent with early experimental observation obtained for MXene (2D transition metal carbide) channels. The predicted optimal water numbers for the cations were then used for AIMD simulations that explicitly include the effects of the solvent. When compared with the cations in bulk solution, our simulations showed that the hydration structure and coordination number (CN) of the solvated cations confined in the MoS2 channel can be significantly altered. We found that larger cations with weaker hydration energy (K+, Rb+, and Cs+) exhibited a distinctive CN decrease under confinement, while smaller cations (Li+ and Na+) retained a similar hydration shell as in the bulk solution. More specifically, the hydration shell of large cations (K+, Rb+, and Cs+) in MoS2 showed similar features of the coordination angle to the bulk, which suggests the partially broken hydration shell with no geometry change under confinement. Our simulations provided insights into the change of the hydration structure of alkaline metal cations under confinement, which may have important implications on their transport in the 1T-MoS2 channel.
Lateral diffusion of single poly(ethylene oxide) chains on the surfaces of glassy and molten polymer films
Authors: Mears Matthew , Zhang Zhenyu J. , Jackson Ryan C. D. , Si Yuchen , Bradford Tigerlily J. B. , Torkelson John M. , Geoghegan Mark
Published: April 2021

Fluorescence correlation spectroscopy was used to show that the temperature-dependent diffusion coefficient of poly(ethylene oxide) (PEO) adsorbed on polystyrene and different poly(alkyl methacrylate) (PAMA) films in aqueous solution exhibited a maximum close to (but below) the surface glass transition temperature, Tgs, of the film. This elevated diffusion was observed over a small range of temperatures below Tgs for these surfaces, and at other temperatures, the diffusion was similar to that on silicon, although the diffusion coefficient for PEO on polystyrene at temperatures above Tgs did not completely decrease to that on silicon, in contrast to the PAMA surfaces. It is concluded that the enhanced surface mobility of the films near the surface glass transition temperature induces conformational changes in the adsorbed PEO. The origin of this narrow and dramatic increase in diffusion coefficient is not clear, but it is proposed that it is caused by a coupling of a dominant capillary mode in the liquid surface layer with the polymer. Friction force microscopy experiments also demonstrate an unexpected increase in friction at the same temperature as the increase in diffusion coefficient.
Machine learning meets chemical physics
Authors: Ceriotti Michele , Clementi Cecilia , Anatole von Lilienfeld O.
Published: April 2021

Over recent years, the use of statistical learning techniques applied to chemical problems has gained substantial momentum. This is particularly apparent in the realm of physical chemistry, where the balance between empiricism and physics-based theory has traditionally been rather in favor of the latter. In this guest Editorial for the special topic issue on “Machine Learning Meets Chemical Physics,” a brief rationale is provided, followed by an overview of the topics covered. We conclude by making some general remarks.
Growth and bacterial dynamics of beef calves during transition from milk/pasture to a high-concentrate diet added with tannins or medium-chain fatty acids
Authors: Yuste S. , Amanzougarene Z. , de la Fuente G. , Fondevila M. , de Vega A.
Published: April 2021

Context Rumen fermentation modulation with feed additives during the transition period to high-concentrate diets might help to avoid bacterial dysbiosis. Aims Assessing the effects of the addition of tannins and medium-chain fatty acids (MCFA) to the adaptation diet of beef calves to a high-concentrate ration on the rate of intake, animal performance and rumen bacterial composition. Methods Eighteen 7-month-old beef calves were abruptly weaned and transitioned over a 28-day period from a milk/grass regime to one of the following diets: a non-supplemented high-concentrate diet plus wheat straw, both given ad libitum (C); C plus 20 g/kg of a 65:35 chestnut and quebracho tannin extract; and C plus 6 g/kg of a commercial mixture of MCFA. Concentrate and straw rate of intake were recorded. Rumen fluid was collected on Days 0, 1, 7, 14, 21 and 28 at 0, 3, 6 and 9 h after feeding to characterise rumen fermentation. Samples from 0 h were analysed to assess the bacterial population using Ion Torrent sequencing. Key results The rate of intake of concentrates and straw, as well as daily gains and final weights, were similar (P > 0.05) among diets. The addition of tannins or MCFA did not modify (P = 0.98) the rumen bacterial population, which was affected by sampling day (P < 0.001). The additives inclusion did not affect relative abundances of the main bacterial taxa (P < 0.05), most of them differing across days (P < 0.001). Diversity indexes (Shannon and richness) declined over sampling days (P < 0.05), although some genera emerged after concentrate inclusion. Conclusions At the doses used in the present experiment, tannins and MCFA did not exert any effect on intake, animal performance and bacterial population. Abrupt transition to high-concentrate diets modified the rumen environment and bacterial community, indicating bacterial adaptation to new environmental conditions. Implications Abrupt transition of 7-month-old calves from milk/pasture to a high-concentrate diet did not impair rumen microbiota or performance; therefore, the use of feed additives seems unnecessary.
Distribution and foraging by non-breeding Caspian Terns on a large temperate estuary of south-western Australia – preliminary investigations
Authors: Stockwell Susie , Greenwell Claire N. , Dunlop James N. , Loneragan Neil R.
Published: April 2021

This study investigates the distribution, abundance, and foraging ecology of Caspian Terns, Hydroprogne caspia, during 5 months of their non-breeding season, in the Peel-Harvey Estuary, south-western Australia. Observations were carried out at 20 sites around the estuary and 6 main areas (13 sites) where terns were abundant. Terns were observed every hour over 5 h time-blocks in the morning, midday, and afternoon, and the number of birds, number of birds foraging and time spent foraging were recorded for 10 min on the hour. From the 760 h of observation, a single overnight roosting site was identified in November, where a maximum of 147 birds were counted in February, after which time the roosting site appeared to shift. The total number of terns, foragers and proportion of time foraging varied amongst the six areas and foraging activity differed amongst times of day. Two areas, both characterised by large, sandy spits adjacent to shallow water, one adjacent to a river mouth and one near an ocean channel, were particularly important for terns and their foraging. Foraging activity was higher in the morning than at other times of day. Although salinity, air temperature, water temperature and wind speed were correlated with the total terns, foragers and proportion of time foraging, the correlations accounted for <25% of the total variation explained. The results of this study provide information for evaluating the use of Caspian Terns as bio-indicators of the Peel-Harvey Estuary and highlights the importance of this system during the non-breeding period.
Automated, multiparametric monitoring of respiratory biomarkers and vital signs in clinical and home settings for COVID-19 patients
Authors: Ni Xiaoyue , Ouyang Wei , Jeong Hyoyoung , Kim Jin-Tae , Tzavelis Andreas , Mirzazadeh Ali , Wu Changsheng , Lee Jong Yoon , Keller Matthew , Mummidisetty Chaithanya K. , Patel Manish , Shawen Nicholas , Huang Joy , Chen Hope , Ravi Sowmya , Chang Jan-Kai , Lee KunHyuck , Wu Yixin , Lie Ferrona , Kang Youn J. , Kim Jong Uk , Chamorro Leonardo P. , Banks Anthony R. , Bharat Ankit , Jayaraman Arun , Xu Shuai , Rogers John A.
Published: April 2021

Significance

Continuous measurements of health status can be used to guide the care of patients and to manage the spread of infectious diseases. Conventional monitoring systems cannot be deployed outside of hospital settings, and existing wearables cannot capture key respiratory biomarkers. This paper describes an automated wireless device and a data analysis approach that overcome these limitations, tailored for COVID-19 patients, frontline health care workers, and others at high risk. Vital signs and respiratory activity such as cough can reveal early signs of infection and quantitate responses to therapeutics. Long-term trials on COVID-19 patients in clinical and home settings demonstrate the translational value of this technology.
Hamaspora hashiokai.
Authors:   USA, USDA-ARS
Published: April 2021

There is little published information on this plant pathogenic fungus, which has a limited geographic distribution. As hosts exist in other regions of the world with similar environmental conditions, this species may pose a threat to native or agricultural plants if introduced.
VPS13D promotes peroxisome biogenesis
Authors: Baldwin Heather A. , Wang Chunxin , Kanfer Gil , Shah Hetal V. , Velayos-Baeza Antonio , Dulovic-Mahlow Marija , Brüggemann Norbert , Anding Allyson , Baehrecke Eric H. , Maric Dragan , Prinz William A. , Youle Richard J.
Published: April 2021

The VPS13 gene family consists of VPS13A–D in mammals. Although all four genes have been linked to human diseases, their cellular functions are poorly understood, particularly those of VPS13D. We generated and characterized knockouts of each VPS13 gene in HeLa cells. Among the individual knockouts, only VPS13D-KO cells exhibit abnormal mitochondrial morphology. Additionally, VPS13D loss leads to either partial or complete peroxisome loss in several transformed cell lines and in fibroblasts derived from a VPS13D mutation–carrying patient with recessive spinocerebellar ataxia. Our data show that VPS13D regulates peroxisome biogenesis.
VPS13D bridges the ER to mitochondria and peroxisomes via Miro
Authors: Guillén-Samander Andrés , Leonzino Marianna , Hanna Michael G. , Tang Ni , Shen Hongying , De Camilli Pietro
Published: April 2021

Mitochondria, which are excluded from the secretory pathway, depend on lipid transport proteins for their lipid supply from the ER, where most lipids are synthesized. In yeast, the outer mitochondrial membrane GTPase Gem1 is an accessory factor of ERMES, an ER–mitochondria tethering complex that contains lipid transport domains and that functions, partially redundantly with Vps13, in lipid transfer between the two organelles. In metazoa, where VPS13, but not ERMES, is present, the Gem1 orthologue Miro was linked to mitochondrial dynamics but not to lipid transport. Here we show that Miro, including its peroxisome-enriched splice variant, recruits the lipid transport protein VPS13D, which in turn binds the ER in a VAP-dependent way and thus could provide a lipid conduit between the ER and mitochondria. These findings reveal a so far missing link between function(s) of Gem1/Miro in yeast and higher eukaryotes, where Miro is a Parkin substrate, with potential implications for Parkinson’s disease pathogenesis.