bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding softening of amorphous materials for FFF applications
Authors: Colón Quintana José Luis , Osswald Tim
Published: February 2022

The work explores the fundamentals of the softening process for amorphous materials expanding on the work presented by Stammers and Beek (Stammers, E. and Beek, W.J. (1969). The melting of a polymer on a hot surface. Polym. Eng. Sci. 9). The pressure induced melt removal process was studied in detail. The process, although fundamental, allows for an understanding of the phase transition of materials during the fused filament fabrication (FFF) process. Experimental results were analyzed using state-of-the-art equipment. A total of four materials were tested. PVC and PC are amorphous materials, and PA6 and PP are semi-crystalline materials. A setup was built to allow the application of a constant force. The resulting melt film was analyzed using computed tomography technology. The experimental results were compared with numerical simulation results originating from COMSOL Multiphysics and the analytical solution derived by Stammers and Beek. Rheological and thermo-mechanical tests were used to find the softening temperature of amorphous materials. Results showed a straightforward transition for the melting temperature of semi-crystalline materials and softening temperature of amorphous materials. It is suggested that for amorphous materials, the glass transition temperature can be used as the softening temperature (T

s
 = T

g
). When comparing all three results (experimental, analytical, and numerical), values are within the same range and magnitude. A good approximation was achieved for PA6 and PVC, which have semi-crystalline and amorphous structures, respectively. Results provide insights into the phase transition process and phase change mechanisms during the extrusion of materials in the fused filament fabrication process.
Tensile, rheological and morphological characterizations of multi-walled carbon nanotube/polypropylene composites prepared by microinjection and compression molding
Authors: Ezat Gulstan S. , Kelly Adrian L. , Youseffi Mansour , Coates Phil D.
Published: February 2022

Polypropylene (PP) reinforced with 2 and 4 wt% of multi-walled carbon nanotubes (MWNT) were melt-blended in twin screw extruder and then molded by compression or micromolding process. The impact of injection speed on the surface morphology, rheological and tensile characteristics was investigated by using a scanning electron microscope, parallel plate rheometry, and tensiometry. Results showed that the tensile properties of micro-molded specimens were remarkably higher than those of the compression molded sheets. Compared to compression molded sheets, micromolded specimens demonstrated up to 40 and 244% higher tensile stiffness and yield strength, respectively, most likely due to the alignment of polymer chain segments in the flow direction induced during the micromolding process. It was observed that the fast filling speed caused a drop in the tensile properties of the nanocomposites and polymer. Rheological examination revealed that the presence of a rheological percolation network in the nanocomposites produced by micromolding and the fast injection speed was beneficial for establishing the percolated network. Morphological examination revealed that the size of nanotube agglomerations that appeared in micromolded specimens was up to five times smaller than in compression molded sheets and the agglomeration size decreased with the increase of the injection speed.
Antifouling improvement of a polyacrylonitrile membrane blended with an amphiphilic copolymer
Authors: Hu Jianlong , He Yingfang , Liu Peng , Shen Xiang
Published: February 2022

The amphiphilic copolymer polyacrylonitrile-co-poly(hydroxyethyl methacrylate) (PAN-co-PHEMA) was readily blended with polyacrylonitrile (PAN) to fabricate a flat-sheet blending membrane through non-solvent induced phase separation (NIPS). In the membrane-forming process, the hydrophilic PHEMA chains are uniformly distributed on the surface, as revealed by the energy-dispersive X-ray tests. The sponge-like sub-layer embedded with droplet-shaped structures is formed at the cross-sections of membranes, because of the high viscosity of the casting solution. With the increase of copolymer concentration, the mean pore size of the blending membranes increases from 26.9 to 99.8 nm, leading to the increase of membrane flux from 93.6 to 205.4 l/(m2h). The incorporation of PAN-co-PHEMA copolymer endows the blending membrane with a rough surface microstructure and enhanced hydrophilicity. The rejection ratio of membranes for emulsified pump oil reaches 99.9%, indicating a prominent separation performance. In the cycle permeation experiments, the flux recovery ratio of the blending membranes is as high as 99.6%, which is much higher than those of PAN membrane. The irreversible fouling of blending membranes induced by oil adsorption is alleviated, and converted into reversible fouling, owing to the reduction of the adhesion force between foulant and membrane surface. These results suggest that the anti-fouling property of PAN membranes has been dramatically strengthened via the addition of PAN-co-PHEMA copolymer.
Virtual and universal braid groups, their quotients and representations
Authors: Bardakov Valeriy , Emel’yanenkov Ivan , Ivanov Maxim , Kozlovskaya Tatyana , Nasybullov Timur , Vesnin Andrei
Published: February 2022

In the present paper, we study structural aspects of certain quotients of braid groups and virtual braid groups.
In particular, we construct and study linear representations

B
n

→

GL

n
⁢

(

n
-
1

)

/
2

⁢

(

Z
⁢

[

t

±
1

]

)

B_{n}\to\mathrm{GL}_{n(n-1)/2}(\mathbb{Z}[t^{\pm 1}])

,

VB
n

→

GL

n
⁢

(

n
-
1

)

/
2

⁢

(

Z
⁢

[

t

±
1

,

t
1

±
1

,

t
2

±
1

,
…
,

t

n
-
1

±
1

]

)

\mathrm{VB}_{n}\to\mathrm{GL}_{n(n-1)/2}(\mathbb{Z}[t^{\pm 1},t_{1}^{\pm 1},t_{2}^{\pm 1},\ldots,t_{n-1}^{\pm 1}])

which are connected with the famous Lawrence–Bigelow–Krammer representation.
It turns out that these representations induce faithful representations of the crystallographic groups

B
n

/

P
n
′

B_{n}/P_{n}^{\prime}

,

VB
n

/

VP
n
′

\mathrm{VB}_{n}/\mathrm{VP}_{n}^{\prime}

, respectively.
Using these representations we study certain properties of the groups

B
n

/

P
n
′

B_{n}/P_{n}^{\prime}

,

VB
n

/

VP
n
′

\mathrm{VB}_{n}/\mathrm{VP}_{n}^{\prime}

.
Moreover, we construct new representations and decompositions of the universal braid groups

UB
n

\mathrm{UB}_{n}

.
Mean-field formulation for mean-variance asset-liability management with cash flow under an uncertain exit time
Authors: Liu Wei , Sun Youfa , Chen Xu
Published: February 2022

The asset-liability management problem with cash flow under an uncertain exit time has been investigated in this article, which is based on the fundamental framework of the mean-variance model in the multi-period version. The liability and random cash flow will affect asset optimization, while the investor may be forced to withdraw from investments with a random probability at each period in our model. The closed-form expressions for the mean-variance optimal portfolio selection and its corresponding efficient frontier are obtained by employing the mean-field formulation and dynamic programming approach. Moreover, some numerical examples are provided to illustrate the validity and accuracy of the theoretical results.
A high order weak approximation for jump-diffusions using Malliavin calculus and operator splitting
Authors: Akiyama Naho , Yamada Toshihiro
Published: February 2022

The paper introduces a novel high order discretization scheme for expectation of jump-diffusion processes by using a Malliavin calculus approach and an operator splitting method. The test function of the target expectation is assumed to be only Lipschitz continuous in order to apply the method to financial problems. Then Kusuoka’s estimate is employed to justify the proposed discretization scheme. The algorithm with a numerical example is shown for implementation.
Smurf2 suppresses the metastasis of hepatocellular carcinoma via ubiquitin degradation of Smad2
Authors: Song Dongqiang , Li Shuyu , Ning Liuxin , Zhang Shuncai , Cai Yu
Published: February 2022

Purpose

Smurf2, one of C2-WW-HECT domain E3 ubiquitin ligases, is closely related to the development and progression in different cancer types, including hepatocellular carcinoma (HCC). This study aims to illustrate the expression and molecular mechanism of Smurf2 in regulating the progression of HCC.

Methods

The expression of Smurf2 in human HCC and adjacent non-tumor liver specimens was detected using tissue microarray studies from 220 HCC patients who underwent curative resection. The relationships of Smurf2 and HCC progression and survival were analyzed using the chi-square test, Kaplan–Meier analysis, and Cox proportional hazards model. For Smurf2 was low expression in HCC cell lines, Smurf2 overexpression cell lines were established. The effect of Smurf2 on cell proliferation and migration was detected by Cell Counting Kit-8 and colony formation assay, and the epithelial–mesenchymal transition (EMT) markers and its transcription factors were tested by immunoblotting. The interaction and ubiquitination of Smad2 by Smurf2 were detected by co-immunoprecipitation and immunoprecipitation assay. Finally, the effect of Smurf2 on HCC was verified using the mouse lung metastasis model.

Results

Smurf2 was downregulated in HCC tissues compared to that of corresponding non-tumor liver specimens. The low expression of Smurf2 in HCC was significantly associated with macrovascular or microvascular tumor thrombus and the impairment of overall survival and disease-free survival. In vitro and in vivo analysis showed that Smurf2 overexpression decreased the EMT potential of HCC cells by promoting the ubiquitination of Smad2 via the proteasome-dependent degradation pathway.

Conclusion

The expression of Smurf2 was downregulated in HCC specimens and affected the survival of patients. Smurf2 inhibited the EMT of HCC by enhancing Smad2 ubiquitin-dependent proteasome degradation.
Asymptomatic and pre-symptomatic infection in Coronavirus Disease 2019 pandemic
Authors: Wang Yutong , Zheng Ke , Gao Wenjing , Lv Jun , Yu Canqing , Wang Lan , Wang Zijun , Wang Bo , Liao Chunxiao , Li Liming
Published: February 2022

With the presence of Coronavirus Disease 2019 (COVID-19) asymptomatic infections detected, their proportion, transmission potential, and other aspects such as immunity and related emerging challenges have attracted people’s attention. We have found that based on high-quality research, asymptomatic infections account for at least one-third of the total cases, whereas based on systematic review and meta-analysis, the proportion is about one-fifth. Evaluating the true transmission potential of asymptomatic cases is difficult but critical, since it may affect national policies in response to COVID-19. We have summarized the current evidence and found, compared with symptomatic cases, the transmission capacity of asymptomatic individuals is weaker, even though they have similar viral load and relatively short virus shedding duration. As the outbreak progresses, asymptomatic infections have also been found to develop long COVID-19. In addition, the role of asymptomatic infection in COVID-19 remains to be further revealed as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants continue to emerge. Nevertheless, as asymptomatic infections transmit the SARS-CoV-2 virus silently, they still pose a substantial threat to public health. Therefore, it is essential to conduct screening to obtain more knowledge about the asymptomatic infections and to detect them as soon as possible; meanwhile, management of them is also a key point in the fight against COVID-19 community transmission. The different management of asymptomatic infections in various countries are compared and the experience in China is displayed in detail.
Design check of cyclically loaded weld seams
Authors: Rudolph Jürgen , Weiß Eckart
Published: February 2022

This paper discusses the design check of cyclically loaded weld seams with improved fatigue performance due to post weld treatment operations such as TIG dressing and grinding. The algorithm is mainly based on the local strain approach to design against fatigue. It accounts for the fundamentally different damage process and conceptual consequences of weld seams with post weld treatment compared to the usual approach based on nominal, structural or notch stresses.
Temperaturverteilung und temperaturbedingte Spannungen beim Warmwalzen
Authors: Goryany Vyacheslav , Beuke Thilo
Published: February 2022

Der vorliegende Beitrag gibt einen analytischen Überblick über die Hauptergebnisse der experimentellen und theoretischen Untersuchungen zu den Temperaturen und Spannungen, die in der Arbeitsschicht der Walzen beim Warmwalzen entstehen, und über die Ursachen der thermischen Beschädigung ihrer Oberfläche im Verlauf des Betriebes.
Topological optical parametric oscillation
Authors: Roy Arkadev , Parto Midya , Nehra Rajveer , Leefmans Christian , Marandi Alireza
Published: February 2022

Topological insulators possess protected boundary states which are robust against disorders and have immense implications in both fermionic and bosonic systems. Harnessing these topological effects in nonequilibrium scenarios is highly desirable and has led to the development of topological lasers. The topologically protected boundary states usually lie within the bulk bandgap, and selectively exciting them without inducing instability in the bulk modes of bosonic systems is challenging. Here, we consider topological parametrically driven nonlinear resonator arrays that possess complex eigenvalues only in the edge modes in spite of the uniform pumping. We show parametric oscillation occurs in the topological boundary modes of one and two dimensional systems as well as in the corner modes of a higher order topological insulator system. Furthermore, we demonstrate squeezing dynamics below the oscillation threshold, where the quantum properties of the topological edge modes are robust against certain disorders. Our work sheds light on the dynamics of weakly nonlinear topological systems driven out-of-equilibrium and reveals their intriguing behavior in the quantum regime.
The crystal structure of hexaquamagnesium(II) (2,4-bis(nitroimino)-6-oxo-1,3,5-triazinane-1,3-diide), C3H15MgN7O12
Authors: Tong Zhang , Guangyuan Zhang , Zishuai Xu , Jian Ruan , Lizhen Chen , Jianlong Wang
Published: February 2022

C3H15MgN7O12, triclinic, P

1
‾

$\overline{1}$

(no. 2), a = 6.7755(2) Å, b = 9.8181(3) Å, c = 11.0775(4) Å, α = 87.717(1)°, β = 78.297(1)°, γ = 70.804(1)°, V = 681.18(4) Å3, Z = 2, R

gt
(F) = 0.0382, wR

ref
(F
2) = 0.1083, T = 150 K.
Formulation of polymeric nanoparticles loaded sorafenib; evaluation of cytotoxicity, molecular evaluation, and gene expression studies in lung and breast cancer cell lines
Authors: Abdellatif Ahmed A. H. , Ali Asmaa T. , Bouazzaoui Abdellatif , Alsharidah Mansour , Al Rugaie Osamah , Tolba Nahla Sameh
Published: February 2022

Sorafenib (SFB) is an anticancer drug with sparingly water solubility and reduced bioavailability. Nanoformulation of SFB can increase its dissolution rate and solubility. The current study aimed to formulate SFB in nanoparticles to improve their solubility. The sorafenib nanoparticles (SFB-PNs) were synthesized using the solvent evaporation method, then evaluated for their particle size, polydispersity index (PDI), zeta-potential, morphological structure, and entrapment efficiency (EE%). Further, the anticancer efficacy in A549 and Michigan Cancer Foundation-7 (MCF-7) cancer cell lines was evaluated. The SFB-NPs were uniform in size, which have 389.7 ± 16.49 nm, PDI of 0.703 ± 0.12, and zeta-potential of −13.5 ± 12.1 mV, whereas transmission electron microscopy showed a well-identified spherical particle. The EE% was found to be 73.7 ± 0.8%. SFB-NPs inhibited the cell growth by 50% after 48 h incubation, with IC50 of 2.26 and 1.28 µg/mL in A549 and MCF-7, respectively. Additionally, SFB-NPs showed a significant decrease (P < 0.05) in p21, and stathmin-1 gene expression levels in both cell lines. Moreover, SFB-NPs showed a significant increase in DNA damage of 25.50 and 26.75% in A549 and MCF-7, respectively. The results indicate that SFB-NPs are a potential candidate with an effective anticancer agent compared with free drugs.
Naturally occurring, natural product inspired and synthetic heterocyclic anti-cancer drugs
Authors: Kaur Manmeet , Kaur Mandeep , Bandopadhyay Tania , Sharma Aditi , Priya Anu , Singh Arvind , Banerjee Bubun
Published: February 2022

This chapter describes the importance and activity of a huge number of commercially available naturally occurring, natural product derived or synthetic heterocyclic anti-cancer drugs.
Common fixed point results via simulation type functions in non-Archimedean modular metric spaces and applications
Authors: Öztürk Mahpeyker , Girgin Ekber
Published: February 2022

In this study, we demonstrate the existence and uniqueness of common fixed points of a generalized (α,β)− simulation contraction on a non-Archimedean modular metric space. We achieve some consequences in non-Archimedean modular metric spaces as an application, using the structure of a directed graph. Eventually, we contemplate the existence of solutions to a class of functional equations standing up dynamic programming with the help of our outcomes.
Ear cupping in EFL classroom interaction: an embodied means of pursuing students’ response
Authors: Amar Cheikhna
Published: February 2022

This paper describes one of the embodied resources language teachers use to pursue a response from students: placing one hand behind the ear in an Ear Cupping (EC) gesture. The data analyzed are taken from over 20 h of English as a Foreign Language (EFL) classroom interaction video-recorded at a Japanese university. The paper explores how teachers use EC to pursue a response in cases when a Second-Pair Part (SPP) contribution from the student(s) is sequentially and temporally delayed, missing or inapposite. The findings suggest that the use of the EC gesture to pursue a response demonstrates the teachers’ orientation toward a normative understanding that a question posed within the classroom should be answered, even when a specific respondent has not been nominated. The analysis therefore reveals that the gesture constitutes an embodied means of monitoring intersubjectivity and increasing engagement in large groups of language learners.
Exploration of an unconventional validation tool to investigate aero engine transonic fan flutter signature
Authors: Viswanatha Rao A.N. , Satish T.N. , Naidu V.P.S. , Jana Soumendu
Published: February 2022

Flutter, an aeroelastic blade vibration phenomena, experienced by the fan of an developmental aero gas turbine engine, result in blade failure. Hence, suitable flutter detection instrumentation is required during engine testing. Flutter signature capture from revolving blades is a challenging task that necessitates either a complicated strain gauge-based rotating instrumentation or a noncontact tip timing system. Authors investigated a unique way for identifying, measuring, and validating flutter signature by assessing wall static pressure pulsations produced during blade tip transit across a casing mounted high bandwidth sensor during this research. The authors devised a mathematical model to explain signal spectrum components that feature both amplitude and angle modulation properties at the same time. The theory was tested using first-stage fan rotor blades that were fluttering in the first flexural mode (1F) and forming the second nodal diameter (2ND). The approach’s estimated blade deflection was compared to measurements taken using a traditional tip timing method up to 7 mm and determined to be within 1% inaccuracy. This research provides a low-cost, easy alternative technique for measuring flutter during engine development testing.
RE
3Rh2Sn4 (RE = Y, Gd–Tm, Lu) – first stannides with Lu3Co2In4 type structure
Authors: Schumacher Lars , Engelbert Simon , Klenner Steffen , Matar Samir F. , Pöttgen Rainer
Published: February 2022

The stannides RE
3Rh2Sn4 (RE = Y, Gd–Tm, Lu) were synthesized from the elements by arc-melting and subsequent annealing (1220 K for RE = Y, Gd–Tm and 1170 K for RE = Lu) in sealed silica ampoules for 11 days. X-ray powder diffraction studies confirm the hexagonal Lu3Co2In4 type structure, space group

P

6
‾

$P\overline{6}$

. The structure of Gd3Rh2Sn4 was refined from single crystal X-ray diffractometer data for a twinned crystal: a = 744.04(6), c = 409.23(4) pm, wR2 = 0.0288, 567 F
2 values and 21 variables. The RE
3Rh2Sn4 stannides derive from the well-known equiatomic stannides RERhSn (≍RE
3Rh3Sn3) by Rh/Sn ordering within the RE
6 trigonal prisms. The striking structural motif is the trigonal planar tin coordination of the Sn2 atoms with 288 pm Sn2–Sn1 distances. The Sn2 atoms carry substantially more negative charge than the Sn1 atoms. This is underlined by 119Sn isomer shifts of δ = 1.86(1) mm s−1 for Sn1 and δ = 2.26(1) mm s−1 for Sn2 detected in the Mössbauer spectrum of Lu3Rh2Sn4. From atoms in molecules (AIM) analysis of the charge density obtained with calculation based on density functional theory (DFT) for Y3Rh2Sn4, the charge transfer proceeds from yttrium towards more electronegative rhodium. Little departure from neutrality is observed for tin whose itinerant s-like states are little involved with the bonding. The site projected density of states (DOS) and the crystal orbital overlap population (COOP) plots further illustrate these observations and reveal major Y–Rh and Rh–Sn bonding, while Y–Sn bonding is weaker.
Scopoletin: a review of its source, biosynthesis, methods of extraction, and pharmacological activities
Authors: Antika Lucia Dwi , Tasfiyati Aprilia Nur , Hikmat Hikmat , Septama Abdi Wira
Published: February 2022

Scopoletin, also known as 6-methoxy-7 hydroxycoumarin, is one of the naturally occurring coumarin commonly found in many edible plants and plays an important role in human health. Despite the various potential pharmacological properties, the biosynthesis process, method of extraction, and mechanism of action on this compound have not been documented well. In this current review, the biosynthesis pathway, distribution of scopoletin in the plant kingdom, and extraction techniques are elaborated. The in vitro, in vivo, and in silico pharmacological studies are also discussed on antioxidant, antimicrobial, anticancer, anti-inflammation, and neuroprotective aspects of scopoletin. This study may help to understand the benefit of scopoletin containing plants and would be beneficial for the prevention and treatment of diseases.
Green and eco-friendly synthesis of TiO2 nanoparticles and their application for removal of cadmium from wastewater: reaction kinetics study
Authors: Irshad Muhammad Atif , Shakoor Muhammad Bilal , Nawaz Rab , Yasmeen Tahira , Arif Muhammad Saleem , Rizwan Muhammad , Rehman Muhammad Zia ur , Ahmad Sajid Rashid , Latif Maria , Nasim Iqra , Ali Shafaqat
Published: February 2022

The heavy metal cadmium (Cd) is known to be a widespread environmental contaminant and a potential toxin that may adversely affect human health across the globe. Green nanotechnology has recently received a lot of attention for developing eco-friendly, low-cost renewable and sustainable materials for the efficient removal of persistent contaminants from wastewater, including heavy metals (HMs). The current study compared the ability of titanium dioxide nanoparticles (TiO2 NPs) synthesized from Trianthema portulacastrum (A) and Chenopodium quinoa (B) extracts to remove Cd from wastewater. The washed biomass of both the plants was dried under shade for a few days and was ground into the fine particles in a blender. The powdered biomass of T. portulacastrum and C. quinoa was soaked separately in distilled water (@ 10 g/100 ml) for 36 h. The stock solution of titanium (0.3 M) was prepared from concentrated titanium tetraisopropoxide (TTIP) and was mixed with the plant extracts at 1:2 ratio of extract to TTIP solution with continuous stirring at room temperature. A light brown scum like TiO2-NPs were obtained at the bottom of china dish and calcined at 450 °C for 4 h. Finally, after natural cooling, the TiO2-NPs were collected and used for the sorption of Cd through wastewater. Sorption attributes of both TiO2 NPs (A, B) were investigated over contact time, dosage of adsorbent, pH, and initial concentration of Cd. Maximum sorption was obtained (46 mgg−1) by TiO2 NPs (A), followed by 44 mg Cd g−1 with TiO2 NPs (B) at pH 4.2, an optimum adsorbent dosage 0.7 g L−1, Cd initial level 30 mg L−1, with contact time of 2 h. Pseudo-second-order kinetic model was suited for adsorption experimental data using both nanoparticles. These results validated the potential use of TiO2 NPs to remove liquified cadmium at high concentrations from the industrial wastewater.
Using Solution-Focused Brief Therapy and Animal-Assisted Therapy With Sexual Minorities: A Pilot Microanalysis Study
Authors: Handley Valerie , Jordan Sara , Fife Stephen , Turns Brie
Published: February 2022

Previous research reveals that sexual minorities have reported negative experiences with mental health professionals due to heteronormative practices (Platt et al., 2018). There is a need for mental health professionals to provide therapy that is more inclusive for sexual minorities. The core ideas and values of animal-assisted therapy (AAT) and solution-focused brief therapy (SFBT) suggest they could promote an inclusive environment. The purpose of this pilot study was to investigate the influence of SFBT and AAT on the content of therapist-client dialogue in simulated therapy sessions with sexual minorities. Findings of this study suggest both SFBT, and SFBT with AAT facilitate positive content in therapist-client dialogue. Additionally, results indicate that after the interaction with the dog in SFBT and AAT, there is significantly greater positive content and less negative content than in SFBT interviews.
Wspieranie uczenia się przez całe życie przez pracodawcę a satysfakcja z pracy na przykładzie pracowników administracji uczelni
Authors:   Szkoła Główna Handlowa w Warszawie, Gigol Tomasz , Pajewska-Kwaśny Renata ,   Szkoła Główna Handlowa w Warszawie
Published: February 2022

The opportunity to learn is one of the factors of the work environment that influences job satisfaction. This article aims at showing the impact of lifelong learning opportunities on job satisfaction. The quantitative research was carried out among employees of Dean’s offices in Polish public and private universities. The study used the MOAQ-JSS job satisfaction questionnaire, the satisfaction with remuneration questionnaire, and the proprietary lifelong learning questionnaire. The statistical effect of mediation was examined using the regression analysis method. The impact of learning opportunities offered by the employer on job satisfaction was noted. Satisfaction with remuneration turned out to be a partial mediator of this dependence. Satisfaction with remuneration, in turn, increases job satisfaction. These dependencies are independent of the age of the employees. The article contributes to a better understanding of the factors influencing job satisfaction and the motivational role of lifelong learning.
Analysis of the Oscillations of Stratified Liquid with Elastic Ice
Authors: Tsvetkov D.O.
Published: February 2022

We study the problem of small motions of an ideal stratified liquid with a free surface totally covered by an elastic ice. The elastic ice is modeled by an elastic plate. We reduce the original initial boundary value problem to an equivalent Cauchy problem for a second-order differential equation in a Hilbert space. We obtain conditions under which there exists a strong (with respect to time) solution of the initial boundary value problem describing the evolution of the hydrodynamic system under consideration. We also study the spectrum of normal oscillations, the basic properties of the eigenfunctions.
Rocking Response of the Rigid Block Under Rectangular Pulse Excitation: A Comparison between ODE and Optimization-Based Solvers
Authors: Gagliardo R. , Portioli F.P.A. , Cascini L. , Landolfo R.
Published: February 2022

In this paper, the response of the rigid block under rectangular pulse excitation is investigated using two different modeling approaches and solvers. The first approach relies on the numerical integration of the differential equation of motion. The second approach is based on the formulation of the dynamic problem in terms of a special class of mathematical programming problem that is the linear complementarity problem. A validation study is carried out comparing the solutions given by the proposed formulation with the ones given by the numerical integration of the differential equation of motion obtained from ODE solvers available in MATLAB®. Potentialities and limitations of the mathematical programming formulation are discussed in terms of energy dissipation and restitution coefficient at impacts and in terms of solution times.
Nonadherence to Medical Treatment
Authors: Everhart Robin S. , Fiese Barbara H.
Published: February 2022

Key Points

Nonadherence to recommended health-related treatment (eg, taking medications as prescribed; keeping appointments; following guidelines for seat belt use, exercise, sleep) in pediatrics occurs about 50% of the time and leads to significant morbidity and mortality.Barriers to adherence include parent and child mental health problems.Depressive symptoms or anxiety (child or parent); resultant lack of motivation, concentration, or desire to adhere to treatment regimensOppositional child behaviorsAdolescent risk-taking behaviorsFamily conflict or disengagementParents who are stressed, overwhelmed, and unable to set routines around treatment adherence or prioritize daily adherenceScreen children with chronic medical conditions for mental health concerns and incorporate a brief discussion of parent mental health and child mental health into each clinic session.Pediatric management of nonadherence includes using motivational interviewing and other "common factors" techniques toAddress barriers to adherence identified through history, screening, and clinical observations.Collaborate with patient and family to select strategies for improving adherence aligned with their intrinsic motivation.Provide referrals for adult or child psychological services and/or family-focused therapy, as needed.
El Programa de Fertilizantes para el Bienestar y el mercado de frijol en México
Authors: Borja-Bravo Mercedes , García-Salazar José Alberto
Published: February 2022

Introducción. El Programa de Fertilizantes para el Bienestar se implementó en México a partir de 2019 y busca aumentar la productividad de cultivos básicos, entre ellos el frijol. Objetivo. Medir los efectos del Programa de Fertilizantes para el Bienestar en el mercado de frijol en México, el beneficio económico que generará en la sociedad y su contribución a la autosuficiencia alimentaria del grano. Materiales y Métodos. Se formuló y validó un modelo de equilibrio espacial que consideró las regiones productoras y consumidoras de frijol en México, se usó información en el año promedio 2017-2019. Resultados. Los resultados indicaron que la producción y el consumo nacional de frijol aumentarían en 228 y 79 miles de t, si el Programa de Fertilizantes para el Bienestar beneficiara a todos los productores de frijol; lo anterior significaría un aumento de 22,1 % en la producción que permitiría bajar las importaciones a cero. El Programa de Fertilizantes para el Bienestar ha promovido una mayor producción de frijol y ha contibuido a la autosuficiencia alimentaria al eliminar las importaciones, además de que generaría beneficios económicos para la sociedad, ya que los excedentes al productor y al consumidor aumentarían en USD$ 429 millones y USD$ 226 millones. Conclusión. El Programa de Fertilizantes para el Bienestar favoreció el crecmimiento de la producción e incentivó el consumo de frijol en México y desincentivó las importaciones de grano; esta acción incrementó la productividad de frijol y contribuyó con la autosuficiencia alimentaria.
Historiografía sobre los enfrentamientos militares centroamericanos, 1808 a 1824
Authors: Arguedas Zamora Aarón
Published: February 2022

Este artículo recorre la historiografía sobre los enfrentamientos militares de Centro América entre 1808 a 1824. En un primer plano se repasaron aquellos escritos que los describieron de una manera general. En un segundo, los relatos sobre cada provincia. Además, se propuso un estudio del periodo en dos fases y la inclusión de nuevos actores en el desarrollo de la independencia. De hecho, el artículo sugiere que las pugnas militares y las fuerzas armadas de Centro América son parte de un proceso que debe examinarse.
Comparison of hamstring quadriceps strength ratios in different combat sports branches
Authors: Tatlıcı Ali , Löklüoğlu Berkay
Published: February 2022

Background and Study Aim. The hamstring and quadriceps muscles can have strength differences because of the sportive activities. It is known that sportive hamstring quadriceps strength imbalance can cause decreasing sportive performance and injuries. Also, each sports branch can have a specific effect on the hamstring quadriceps strength ratio. Therefore, the aim of this study was to examine the effects of different combat sports branches on the hamstring quadriceps ratio. 
Material and Methods. Wrestlers (N=10), boxers (N=10), wushu athletes (N=10) voluntarily participated in the study (also university students). Subjects were administered standard warm-up and then a strength measurement test was performed. Subjects performed knee extensor (quadriceps) and flexor (hamstring) isokinetic strength test (concentrically) with his dominant leg at 60° angular velocity with by Cybex device (Cybex NORM®. Humac. CA. USA). Peak and average strength were recorded automatically by the device. The SPSS package program was used in the analysis of the data. The isokinetic strength measurements of three groups were analyzed with one-way ANOVA.
Results. There were no significant differences between groups’ peak isokinetic strength ratio (wrestlers 0.58±0.09 boxers 0.56±0.07 and wushu athletes 0.57±0.12). Also, the average isokinetic strength ratio was not significantly different (wrestlers 0.56±0.08. boxers 0.60±0.08 and wushu athletes 0.53±0.11).
Conclusions. According to the results, it can be said that combat sports athletes' hamstring quadriceps ratio can be affected by their sports branches, also by characteristics and training levels.
An insight into Short-sprint coaches’ knowledge and use of periodisation models and training methods - Sri Lankan context
Authors: Sellathurai Jeganenthiran , Draper Nick
Published: February 2022

Background and Study Aim. Periodised training strategies, due to their demonstrated success in improving athletic performance, have become increasingly utilised by coaches, athletes, and strength and conditioning practitioners as a key training methodology. As a consequence, a coach’s knowledge of periodisation and training methods have become increasingly important for improvement of sport-sprint performance. Despite their importance of performance at the elite level, it was suspected that little is known about the Sri Lankan context. As a result, the purpose of this formative exploratory study was to examine knowledge about, and application of, periodisation and training methods by Sri Lankan elite-level coaches working with short-sprint athletes.

Material and Methods. With institutional ethics approval, ten (n=10) expert short-sprint coaches volunteered to participate in the study, with data collected via semi-structured interviews. Data were analysed inductively, to identify ‘patterns’, ‘themes’ and ‘categories’ using the NVivo 12 qualitative software.

Results. Four primary themes emerged from the interview data. These included “Periodisation models”, “Monitoring training”, “Strength development”, and “Speed development”. Findings revealed that coaches reported minimal or inadequate knowledge of periodised training and consequently, there did appear to be a gap between coach knowledge of periodised training, but additionally in regard to general training methodology; including aspect such as prescribing strength and speed training loads and, monitoring of training loads. The coaches believed that their knowledge was inadequate to support athletes with Olympic level potential.

Conclusions. The findings identified a potential knowledge gap in coach education and development for elite sprint coaches in Sri Lanka.
Machine learning as a tool to engineer microstructures: Morphological prediction of tannin-based colloids using Bayesian surrogate models
Authors: Jin Soo-Ah , Kämäräinen Tero , Rinke Patrick , Rojas Orlando J. , Todorović Milica
Published: February 2022

Oxidized tannic acid (OTA) is a useful biomolecule with a strong tendency to form complexes with metals and proteins. In this study we open the possibility to further the application of OTA when assembled as supramolecular systems, which typically exhibit functions that correlate with shape and associated morphological features. We used machine learning (ML) to selectively engineer OTA into particles encompassing one-dimensional to three-dimensional constructs. We employed Bayesian regression to correlate colloidal suspension conditions (pH and pKa) with the size and shape of the assembled colloidal particles. Fewer than 20 experiments were found to be sufficient to build surrogate model landscapes of OTA morphology in the experimental design space, which were chemically interpretable and endowed predictive power on data. We produced multiple property landscapes from the experimental data, helping us to infer solutions that would satisfy, simultaneously, multiple design objectives. The balance between data efficiency and the depth of information delivered by ML approaches testify to their potential to engineer particles, opening new prospects in the emerging field of particle morphogenesis, impacting bioactivity, adhesion, interfacial stabilization, and other functions inherent to OTA.

Impact statement

Tannic acid is a versatile bio-derived material employed in coatings, surface modifiers, and emulsion and growth stabilizers, which also imparts mild anti-viral health benefits. Our recent work on the crystallization of oxidized tannic acid (OTA) colloids opens the route toward further valuable applications, but here the functional properties tend to depend strongly on particle morphology. In this study, we eschew trial-and-error morphology exploration of OTA particles in favor of a data-driven approach. We digitalized the experimental observations and input them into a Gaussian process regression algorithm to generate morphology surrogate models. These help us to visualize particle morphology in the design space of material processing conditions, and thus determine how to selectively engineer one-dimensional or three-dimensional particles with targeted functionalities. We extend this approach to visualize other experimental outcomes, including particle yield and particle surface-to-volume ratio, which are useful for the design of products based on OTA particles. Our findings demonstrate the use of data-efficient surrogate models for general materials engineering purposes and facilitate the development of next-generation OTA-based applications.

Graphic abstract
Pemetaan dan Evaluasi Kesehatan Hutan Mangrove di Kabupaten Karawang Menggunakan Landsat Multitemporal
Authors: Muzakki Salman Ahmad , Mourniaty Acacia Zeny Araminta , Rahardjo Priyanto , Triyono Heri
Published: February 2022

Kabupaten Karawang memiliki panjang pantai 76,42 km dan luas pesisir lebih 2/3 dari luas wilayah seluruhnya atau sekitar 1.168,85 km2 atau 3,73% dari luas Provinsi Jawa Barat yang merupakan sumber daya perikanan tangkap dan ekosistem mangrove, akan tetapi bencana alam terjadi di beberapa pantai seperti abrasi, sedimentasi yang massif dan tumpahan minyak. Penelitian ini bertujuan mengetahui perubahan hutan mangrove setelah menjadi Kawasan wisata, perubahan hutan mangrove dalam 20 tahun, dan mengetahui tingkat Kesehatan hutan mangrove. Penelitian ini dilakukan dari tanggal 2–30 maret 2020 di kawasan wisata mangrove yaitu desa Pakis jaya, Sedari, Pasir putih, Tangkolak barat, Tangkolak timur. Penelitian dilakukan dengan meneliti hasil citra satelit tahun 2000-2020 (multitemporal) menggunakan citra Landsat 5 dan 8 dan diolah dengan metode NDVI (Normalized Difference Vegetation Index) untuk melihat tingkat Kesehatan vegetasi, kemudian untuk validasi data satelit menggunakan data lapangan dengan metode hemisperichal photography untuk melihat kepadatan hutan mangrove dilihat dari tutupan (cover) vegetasi. Hasil dari penelitian ini adalah setiap Kawasan setelah menjadi Kawasan wisata bertambah luas dan tingkat kesehatanya, pada tahun 2005-2010 terjadi penurunan tingkat Kesehatan di wilayah Pakis jaya disebabkan terjadinya abrasi pada tahun 2008, akan tetapi didaerah lain terjadi penambahan luas dan juga tingkat kesehatanya.
La relevancia moral de la estructuración del tiempo humano en la empresa
Authors: Mercado Juan-Andrés
Published: February 2022

Leonardo Polo impartió numerosos cursos y seminarios a gente de empresa a lo largo de su carrera académica, ilustrando las manifestaciones prácticas de su propuesta antropológica. Entre las nociones fundamentales que desarrolla están la relación entre el modo humano de proyectarse en el futuro, la esperanza y la apertura de la persona. En diferentes ocasiones alude a sus ideas sobre la razón práctica, la invención de instrumentos y la innovación, siempre vinculadas a la noción de pensamiento sistémico. Polo entiende las organizaciones como escenarios de crecimiento personal, con una concepción del liderazgo que evita las derivas narcisistas y conecta con las virtudes clásicas de la fortaleza y la templanza. Su concepción de la motivación está asociada a la verdad, la confianza y al mejoramiento continuo de la comunicación.
Diagnostic potential of non-invasive mapping in the treatment of ventricular tachycardia in a patient with postinfarction scar: a case report
Authors: Dedukh E. V. , Yashkov M. V. , Artyukhina E. A. , Revishvili A. Sh.
Published: February 2022

A case report of ventricular tachycardia (VT) treatment in a patient after myocardial infarction using non-invasive real-time electrophysiological mapping is presented. This clinical observation demonstrates the diagnostic possibilities of non-invasive mapping in the treatment of VT with hemodynamic instability. Non-invasive mapping can be used as a method for visualizing the early activation and slow conduction zones in hemodynamically instable VT, when effective endocardial mapping is not possible.
Upper gastrointestinal lesions in patients with lower extremity peripheral artery disease: data from a retrospective analysis
Authors: Seljanina A. A. , Dolgushina A. I. , Fokin A. A. , Kuznecova A. S. , Genkel' V. V.
Published: February 2022

Aim. To assess the prevalence and structure of upper gastrointestinal (GI) lesions, as well as the factors associated with their development, in patients with lower extremity peripheral artery disease (PAD).

Material and methods. This retrospective analysis of medical records with lower extremity PAD includes data from 258 patients. All patients underwent multislice computed tomography angiography of abdominal aortic visceral branches and lower limb arteries, as well as esophagogastroduodenoscopy.

Results. Endoscopic evidence of upper GI lesions was detected in 164 (63,6%) patients. In particular, gastroduodenal erosions and ulcers were observed in 57,8% of patients. All patients were divided into two groups: group I — 149 (57,8%) patients with gastroduodenal erosions and ulcers, group II  — 109 (42,2%) patients without it. In group I patients, a higher incidence of mesenteric artery disease was recorded  — 61,7 vs 43,1% (p=0,003). An independent factor associated with the development of gastroduodenal erosions and ulcers in patients with PAD is mesenteric artery disease (relative risk: 4,43; 95% confidence interval: 1,15-17,12 (p=0,031)).

Conclusion. In patients with lower extremity PAD, upper GI diseases (63,6%) occur with a high frequency, while gastroduodenal erosions and ulcers was observed in 90,9% of them. The factors associated with the development of erosions and ulcers in patients with lower extremity PAD include mesenteric artery atherosclerosis.
Effusive pericarditis in the pathogenesis of cardiac arrhythmias in COVID-19: a case series
Authors: Sukmarova Z. N. , Saidova M. A. , Ovchinnicov Yu. V.
Published: February 2022

A wide variety of non-pulmonary manifestations of a coronavirus disease 2019 (COVID-19) has enriched clinical performance of cardiac diseases with atypical symptoms. Two COVID-19 cases are presented, where sinus bradycardia and syncope, which are rare in COVID-19, were the leading ones after the infection. The patients had no prior cardiovascular diseases, while the examination did not detected neurological pathology and myocarditis. Echocardiography showed relatively small pericardial effusion, which is supposed to be a cause of the symptoms as the diagnosis to exclude. A local buildup of inflammatory fluid around the sinus node and extensive ganglion plexuses around the atria can possibly affect the automatism and chronotropic compensation in addition to the myocardial inflammation. As part of the treatment against the hydropericardium syndrome, the symptoms disappeared, without reoccurring within subsequent 6-month follow-up. The third clinical case regards the pandemic outbreak, when we could not even suspect that the systemic inflammation would persist for many months after COVID-19 and radiofrequency ablation can lead to sudden cardiac death.
Centrifuge modelling of lead retardation in soil–bentonite cut-off walls
Authors: Zhan Liang-Tong , You Yu-Qing , Zhao Rui , Chen Cheng , Chen Yun-min
Published: February 2022

Soil–bentonite (SB) walls are commonly used as barriers for in situ containments at landfills. SB walls are designed to control the movement of persistent pollutants such as heavy metals in the long term. This paper presents centrifuge and numerical modelling of 50 years of performance of a loess-amended SB (LSB) wall in comparison with a conventional SB wall. Both walls were 28 m high and subjected to a hydraulic head difference of 2 m in the prototype. A purposely designed apparatus was developed to impose the hydraulic head and a pollutant loading of 200 mg/l lead(II) on two barriers simultaneously. The apparatus was loaded on the ZJU400 geotechnical centrifuge and spun to 100g. Similitudes of dispersion and adsorption of lead(II) in a centrifuge are discussed. Stress redistribution was observed in small-scale walls due to the enhanced soil arching effect. The lead(II) migration distance in the LSB wall after 50 years was 44.3% shorter than that in the SB wall. The predicted breakthrough time for the LSB wall was 149.1% longer than that for the SB wall when the thickness was 0.6 m. Retardation effects could be attributed to the significant ability of loess to absorb lead(II).