bluuebunny/crossref_metadata_2025 huggingface dataset:
Symmetry aspects in the macroscopic dynamics of magnetorheological gels and general liquid crystalline magnetic elastomers
Authors: Pleiner Harald , Brand Helmut R.
Published: January 2021

We investigate theoretically the macroscopic dynamics of various types of ordered magnetic fluid, gel, and elastomeric phases. We take a symmetry point of view and emphasize its importance for a macroscopic description. The interactions and couplings among the relevant variables are based on their individual symmetry behavior, irrespective of the detailed nature of the microscopic interactions involved. Concerning the variables we discriminate between conserved variables related to a local conservation law, symmetry variables describing a (spontaneously) broken continuous symmetry (e.g., due to a preferred direction) and slowly relaxing ones that arise from special conditions of the system are considered. Among the relevant symmetries, we consider the behavior under spatial rotations (e.g., discriminating scalars, vectors or tensors), under spatial inversion (discriminating e.g., polar and axial vectors), and under time reversal symmetry (discriminating e.g., velocities from polarizations, or electric fields from magnetic ones). Those symmetries are crucial not only to find the possible cross-couplings correctly but also to get a description of the macroscopic dynamics that is compatible with thermodynamics. In particular, time reversal symmetry is decisive to get the second law of thermodynamics right. We discuss (conventional quadrupolar) nematic order, polar order, active polar order, as well as ferromagnetic order and tetrahedral (octupolar) order. In a second step, we show some of the consequences of the symmetry properties for the various systems that we have worked on within the SPP1681, including magnetic nematic (and cholesteric) elastomers, ferromagnetic nematics (also with tetrahedral order), ferromagnetic elastomers with tetrahedral order, gels and elastomers with polar or active polar order, and finally magnetorheological fluids and gels in a one- and two-fluid description.
Hybrid nanomaterials of biomolecule corona coated magnetic nanoparticles and their interaction with biological systems
Authors: Dutz Silvio , Weidner Andreas , von der Lühe Moritz , Gräfe Christine , Biehl Philip , Demut Johanna , Warncke Paul , Jungmann Sandra , Fischer Dagmar , Schacher Felix H. , Clement Joachim H.
Published: January 2021

Magnetic nanoparticles (MNPs) are interesting for various applications in medicine. If administered to a biological system like the human body, a so-called biomolecule corona is formed on the surface of the particles, which highly determines the biological fate of the particles. To elucidate whether a preconditioning of the MNPs by incubation with biomolecules influences biocompatibility and bioavailability, the formation of such a corona was investigated in more detail. For this, the influence of particle characteristics, e.g., surface charge, as well as various incubation parameters on the resulting corona was investigated. It was found that the biomolecule corona is formed immediately after bringing together the particles with the biomolecule source. By variation of the biomolecule content of the incubation medium, the size of the corona can be modulated. Regarding the interaction of the nanoparticles with cells, it was shown that the presence of a biomolecule corona reduces the interaction and that a more pronounced biomolecule corona leads to a reduced uptake of the magnetic nanohybrids into the cells. Cell viability tests confirmed biocompatibility of the biomolecule-coated particles. A more pronounced corona promotes a higher cell viability. By using a shell-less hen’s egg model, no or reduced adverse effects of all biomolecule-coated MNP for this in vivo test were found. Resulting from these investigations, we were able to demonstrate that our newly developed nanohybrids significantly reduce in vivo toxicity compared to uncoated MNPs.
Multifunctionality by dispersion of magnetic nanoparticles in anisotropic matrices
Authors: Eremin Alexey , Nádasi Hajnalka , Stannarius Ralf
Published: January 2021

Interactions between magnetic nanoparticles and an anisotropic environment give rise to a variety of new magneto-optical, rheological and mechanical phenomena. This opens new avenues for developing novel multifunctional materials. In the course of this project, we investigated three types of anisotropic systems: dispersions of shape-anisotropic nanocrystals, magnetically doped molecular and colloidal liquid crystals, and organoferrogels. They were investigated by means of magneto-optical observations and by a magneto-mechanical torsion pendulum method.
Rotational dynamics of magnetic nanoparticles in different matrix systems
Authors: Ludwig Frank , Remmer Hilke
Published: January 2021

Dynamic magnetic measurements on magnetic nanoparticle (MNP) samples have been widely used for the determination of structural MNP parameters as well as for the realization of bioassays. On the other hand, proposed that the MNPs are thermally blocked, i.e., that the dynamics are dominated by the Brownian rotation, and knowing the distribution of their hydrodynamic size, information on the matrix properties can be obtained. In contrast to conventional rheology, the local environment of the MNPs is sensed on the nanoscale so that important information on the embedding of MNPs in the matrix and thus the particle-matrix interaction is obtained. Depending on the characteristic length scales of the matrix and the size of the MNPs, rheological parameters, such as viscosity and shear modulus, derived from nanorheological measurements can differ from the values obtained from conventional rheology. To measure the MNP dynamics, different experimental techniques can be applied. In this contribution, the focus lies on ac susceptometry and fluxgate magnetorelaxometry. The analysis of the complex ACS spectra is generally carried out within a modified Debye model. Different approaches for the estimation of rheological parameters from the complex ACS spectra will be presented. Two model systems will exemplarily be discussed in detail. As a Newtonian matrix system, water-glycerol mixtures were studied. It is demonstrated that the dynamic viscosity can accurately be estimated from ACS measurements on well thermally blocked single-core as well as on multicore MNP systems, which include Brownian and Néel dynamics. As a viscoelastic matrix system, aqueous gelatin solutions were studied. Gelatin is known to be a Voigt-Kelvin model system, in which elastic and viscous forces are parallel. In particular, we studied the gelation dynamics by repetitive measurements of the complex ACS spectrum. Different approaches to derive viscosity and shear modulus are applied and compared. In order to identify magnetoviscous effects in dynamic magnetic measurements, the magnetic field dependence of the Brownian relaxation time has to be eliminated. ACS measurements on various sufficiently strongly diluted aqueous MNP suspensions were performed in dependence of ac field amplitude and superimposed dc field strength and compared to theory. Excellent agreement was found.
Functionalization of biopolymer fibers with magnetic nanoparticles
Authors: Strassburg Stephen , Mayer Kai , Scheibel Thomas
Published: January 2021

Hybrid fibers consisting of biopolymers and inorganic nanoparticles are receiving increasing attention due to their unique properties. Commonly, the nanoparticles are chosen for their intrinsic properties such as magnetic, thermal, or electrical conductivity. The biopolymer component of the hybrid fiber is chosen for its mechanical properties and ability to act as a scaffold or matrix for the nanoparticles. While there are many fiber-forming synthetic polymers, there has been a recent interest in replacing these systems with biopolymers due to their sustainability, biocompatibility, nontoxicity, and biodegradability. Fibers made from biopolymers have one additional benefit over synthetic polymers as they make good scaffolds for embedding nanoparticles without the need of any additional bonding agents. In particular, naturally occurring biopolymers such as proteins exhibit a myriad of interactions with nanoparticles, including ionic, H-bonding, covalent, Van der Waals, and electrostatic interactions. The diverse range of interactions between magnetic nanoparticles and biopolymers makes resulting hybrid fibers of particular interest as magnetic-responsive materials. Magnetically responsive hybrid biopolymer fibers have many features, including enhanced thermal stabilities, strong mechanical toughness, and perhaps most interestingly multifunctionality, allowing for a wide range of applications. These applications range from biosensing, filtration, UV shielding, antimicrobial, and medical applications, to name a few. Here, we review established hybrid fibers consisting of biopolymers and nanoparticles with a primary focus on biopolymers doped with magnetic nanoparticles and their various putative applications.
Studies about the design of magnetic bionanocomposite
Authors: Müller Robert , Kuchinka Janna , Heinze Thomas
Published: January 2021

Magnetic nanocomposites are a class of smart materials that have attracted recent interest as drug delivery systems or as medical implants. A new approach toward the biocompatible nanocomposites suitable for remote melting is presented. It is shown that magnetite nanoparticles (MNPs) can be embedded into a matrix of biocompatible thermoplastic dextran esters. For that purpose, fatty acid esters of dextran with adjustable melting points in the range of 30–140 °C were synthesized. Esterification of the polysaccharide by activation of the acid as iminium chlorides guaranteed mild reaction conditions leading to high-quality products as confirmed by Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy as well as by gel permeation chromatography (GPC). A method for the preparation of magnetically responsive bionanocomposites (BNCs) was developed consisting of combined dissolution/suspension of the dextran ester and hydrophobized MNPs in an organic solvent followed by homogenization with ultrasonication, casting of the solution, drying and melting of the composite for a defined shaping. This process leads to a uniform distribution of MNPs in BNC as revealed by scanning electron microscope (SEM). Samples of different geometries were exposed to high-frequency alternating magnetic field (AMF). It could be shown that defined remote melting of such biocompatible nanocomposites is possible for the first time. This may lead to a new class of magnetic remote-control systems, which are suitable for controlled release applications or self-healing materials. BNCs containing biocompatible dextran fatty acid ester melting close to human body temperature were prepared and loaded with Rhodamine B (RhB) or green fluorescent protein (GFP) as model drugs to evaluate their potential use as drug delivery system. The release of the model drugs from the magnetic BNC investigated under the influence of a high-frequency AMF (20 kA/m at 400 kHz) showed that on-demand release is realized by applying the external AMF. The BNC possessed a long-term stability (28 d) of the incorporated iron oxide particles after incubation in artificial body fluids. Temperature-dependent mobility investigations of MNP in the molten BNC were carried out by optical microscopy, magnetometry, alternating current (AC) susceptibility, and Mössbauer spectroscopy measurements. Optical microscopy shows a movement of agglomerates and texturing in the micrometer scale, whereas AC susceptometry and Mössbauer spectroscopy investigations reveal that the particles perform diffusive Brownian motion in the liquid polymer melt as separated particles rather than as large agglomerates. Furthermore, a texturing of MNP in the polymer matrix by a static magnetic field gradient was investigated. First results on the preparation of cross-linkable dextran esters are shown. Cross-linking after irradiation of the BNC prevents melting that can be used to influence texturing procedures.
Magneto-mechanical properties of elastic hybrid composites
Authors: Borin Dmitry , Stepanov Gennady
Published: January 2021

The paper gives an overview of tunable elastic magnetic composites based on silicon rubber matrix highly filled with a magnetic soft and hard filler. The magnetic soft phase, which is represented by iron microparticles, allows active control of the physical properties of the composites, while the magnetically hard phase (e.g. neodymium–iron–boron alloy microparticles) is mainly responsible for passive adjustment of the composite. The control is performed by the application of an external magnetic field in situ, and passive adjustment is performed by means of pre-magnetization in order to change material remanent magnetization, i.e. the initial state. The potential and limits of active control and passive tuning of these composites in terms of their magneto-mechanical behavior are presented and discussed.
Hybrid magnetic elastomers prepared on the basis of a SIEL-grade resin and their magnetic and rheological properties
Authors: Stepanov Gennady V. , Borin Dmitry Yu. , Bakhtiiarov Anton V. , Storozhenko Pavel A.
Published: January 2021

Hybrid magnetic elastomers (HMEs) belong to a novel type of magnetocontrollable elastic materials capable of demonstrating extensive variations of their parameters under the influence of magnetic fields. Like all cognate materials, HMEs are based on deformable polymer filled with a mixed or modified powder. The complex of properties possessed by the composite is a reflection of interactions occurring between the polymer matrix and the particles also participating in interactions among themselves. For example, introduction of magnetically hard components into the formula results in the origination of a number of significantly different behavioral features entirely unknown to magnetorheological composites of the classic type. Optical observation of samples based on magnetically hard filler gave the opportunity to establish that initial magnetization imparts magnetic moments to initially unmagnetized grains, as a result of which chain-like structures continue to be a feature of the material even after external field removal. In addition, applying a reverse field causes them to turn into the polymer as they rearrange into new ring-like structures. Exploration of the relationship between the rheological properties and magnetic field conducted on a rheometer using vibrational mechanical analysis showed an increase of the relative elastic modulus by more than two orders of magnitude or by 3.8 MPa, whereas the loss factor exhibited steady growth with the field up to a value of 0.7 being significantly higher than that demonstrated by elastomers with no magnetically hard particles. At the same time, measuring the electroconductivity of elastomers filled with a nickel-electroplated carbonyl iron powder made it possible to observe that such composites demonstrated an increase of variation of the resistivity of the composite influenced by magnetic field in comparison to elastomers containing untreated iron particles. The studies conducted indicate that this material exhibits both magnetorheological and magnetoresistive effect and does indeed have the potential for use in various types of devices.
Magnetostriction in elastomers with mixtures of magnetically hard and soft microparticles: effects of nonlinear magnetization and matrix rigidity
Authors: Stolbov Oleg V. , Sánchez Pedro A. , Kantorovich Sofia S. , Raikher Yuriy L.
Published: January 2021

In this contribution, a magnetoactive elastomer (MAE) of mixed content, i.e., a polymer matrix filled with a mixture of magnetically soft and magnetically hard spherical particles, is considered. The object we focus on is an elementary unit of this composite, for which we take a set consisting of a permanent spherical micromagnet surrounded by an elastomer layer filled with magnetically soft microparticles. We present a comparative treatment of this unit from two essentially different viewpoints. The first one is a coarse-grained molecular dynamics simulation model, which presents the composite as a bead-spring assembly and is able to deliver information of all the microstructural changes of the assembly. The second approach is entirely based on the continuum magnetomechanical description of the system, whose direct yield is the macroscopic field-induced response of the MAE to external field, as this model ignores all the microstructural details of the magnetization process. We find that, differing in certain details, both frameworks are coherent in predicting that a unit comprising magnetically soft and hard particles may display a nontrivial reentrant (prolate/oblate/prolate) axial deformation under variation of the applied field strength. The flexibility of the proposed combination of the two complementary frameworks enables us to look deeper into the manifestation of the magnetic response: with respect to the magnetically soft particles, we compare the linear regime of magnetization to that with saturation, which we describe by the Fröhlich–Kennelly approximation; with respect to the polymer matrix, we analyze the dependence of the reentrant deformation on its rigidity.
Electric degradation in PZT piezoelectric ceramics under a DC bias
Authors: Zhang Jing , Pan Pinghua , Jiang Ping , Qin Jie , Hu Jiansong
Published: January 2021

In order to accurately evaluate the service life and failure mechanism of the PZT piezoelectric ceramics, the electric degradation process of the PZT ceramics with and sans doping under a DC voltage of 380V, in a surrounding environment of 90∘C and 85% RH has been investigated using a self-made device. The experimental results show that the degradation rate of the pure PZT ceramic is lower than that of ceramics with doping in the same condition. Furthermore, the electrical properties of the ceramics tend to decrease during the electric degradation. The doping increases the defects of ceramics, resulting in that the silver ion transfer from the anode to the cathode under the continuous DC bias, which can further form a metal band, increasing the conductivity, but deteriorating the service life.
A New Portable Device to Reliably Measure Maximal Strength and Rate of Force Development of Hip Adduction and Abduction
Authors: Gonçalves Basílio A.M. , Mesquita Ricardo N.O. , Tavares Francisco , Brito João , Correia Paulo , Santos Paulo , Mil-Homens Pedro
Published: January 2021

Gonçalves, BM, Mesquita, RNO, Tavares, F, Brito, J, Correia, P, Santos, P, and Mil-Homens, P. A new portable device to reliably measure maximal strength and rate of force development of hip adduction and abduction. J Strength Cond Res 36(9): 2465–2471, 2022—Groin injuries are a major issue in sports involving kicking or quick changes of direction. Decreased hip adduction and abduction strength have been indicated as one of the main risk factors for groin injury. The methods currently available to measure hip adduction and abduction strength are reliable but highly dependent on the evaluator skills. Furthermore, several studies have reported the reliability of maximal strength (MVIC), but very few studies investigated the reliability of explosive strength (RFD), a parameter that has been previously shown to have a higher functional value. The aim of the current investigation was to assess the reliability of a user-independent portable dynamometer that concurrently measures MVIC and RFD. Twenty-five healthy young subjects performed maximal isometric hip adduction and abduction in both sitting and supine positions. Measurements occurred in 2 different days separated by 48–72 hours. Test-retest reliability was calculated for both MVIC and RFD. Both MVIC and RFD showed good relative reliability (intraclass correlation coefficient = 0.77–0.98) with no differences between positions or muscle actions. Measurement error was similar between positions for MVIC in both hip adduction and abduction. Measurements of RFD showed higher reliability using a time window of at least 0–100 milliseconds, and lower measurement error was observed in sitting for adduction and in supine for abduction. This study shows that portable dynamometry can be used to concurrently measure hip adduction and abduction maximal and explosive strength, with levels of reliability that are similar to previously described methods.
Effects of a Strength-Dominated Exercise Program on Physical Fitness and Cognitive Performance in Preschool Children
Authors: Wick Kristin , Kriemler Susi , Granacher Urs
Published: January 2021

Wick, K, Kriemler, S, and Granacher, U. Effects of a strength-dominated exercise program on physical fitness and cognitive performance in preschool children. J Strength Cond Res 35(4): 983–990, 2021—Childhood is characterized by high neuroplasticity that affords qualitative rather than quantitative components of physical activity to maximize the potential to sufficiently develop motor skills and foster long-term engagement in regular physical activity. This study examined the effects of an integrative strength-dominated exercise program on measures of physical fitness and cognitive performance in preschool children. Children aged 4–6 years from 3 kindergartens were randomized into an intervention (INT) group (n = 32) or a control group (n = 22). The 10-week intervention period was conducted 3 times per week (each session lasted 30 minutes) and included exercises for the promotion of muscle strength and power, coordination, and balance. Pre and post training, tests were conducted for the assessment of muscle strength (i.e., handgrip strength), muscle power (i.e., standing long jump), balance (i.e., timed single-leg stand), coordination (hopping on right/left leg), and attentional span (i.e., “Konzentrations-Handlungsverfahren für Vorschulkinder” [concentration-action procedure for preschoolers]). Results from 2 × 2 repeated-measures analysis of covariance revealed a significant (p ≤ 0.05) and near significant (p = 0.051) group × time interaction for the standing long jump test and the Konzentrations-Handlungsverfahren. Post hoc tests showed significant pre-post changes for the INT (p < 0.001; d = 1.53) but not the CON (p = 0.72; d = 0.83). Our results indicate that a 10-week strength-dominated exercise program increased jump performance with a concomitant trend toward improvements in attentional capacity of preschool children. Thus, we recommend implementing this type of exercise program for preschoolers.
Can Team-Sport Athletes Accurately Run at Submaximal Sprinting Speeds? Implications for Rehabilitation and Warm-Up Protocols
Authors: Darrall-Jones Joshua , Roe Gregory , Cremen Eoin , Jones Ben
Published: January 2021

Darrall-Jones, J, Roe, G, Cremen, E, and Jones, B. Can team-sport athletes accurately run at submaximal sprinting speeds? Implications for rehabilitation and warm-up protocols. J Strength Cond Res 36(8): 2218–2222, 2022—The aim of this study is to examine the ability of team-sport athletes to accurately run at a range of submaximal sprint velocities (60–90% maximal velocity; Vmax) under verbal instruction without any objective feedback. Twelve professional male rugby union players (age 19.7 ± 0.9 years, body mass 98.3 ± 13.9 kg, height 184.0 ± 7.5 cm) were verbally instructed to complete three 40-m sprints at each of 60, 70, 80, and 90% of Vmax in a randomized order. Percentage Vmax achieved during each sprint was compared with criterion velocities calculated from Vmax testing undertaken a week prior. Players underestimated (ran faster) their sprint velocity when asked to run at 60% (very large to extremely large mean bias, 23%; range, 57–88% Vmax), 70% (large to very large, 11%; 67–93% Vmax), and 80% (small, 2%; 71–91% Vmax) of their Vmax, whereas overestimated (ran slower) their sprint velocity when asked to run at 90% Vmax (moderate, −4%; 77–95% Vmax). Team sport players may require objective feedback when performing submaximal sprinting to ensure that velocities achieved are similar to those prescribed. This may be particularly important where graded exposure to maximum velocities is required, for example during rehabilitation or warm-ups.
Potential Predictors of Vertical Jump Performance: Lower Extremity Dimensions and Alignment, Relative Body Fat, and Kinetic Variables
Authors: Daugherty Hailey J. , Weiss Lawrence W. , Paquette Max R. , Powell Douglas W. , Allison Lindsey E.
Published: January 2021

Daugherty, HJ, Weiss, LW, Paquette, MR, Powell, DW, and Allison, LE. Potential predictors of vertical jump performance: Lower extremity dimensions and alignment, relative body fat, and kinetic variables. J Strength Cond Res 35(3): 616–625, 2021—The association of structural and kinetic variables with restricted vertical jump (RVJ) displacement without and with added mass was examined in 60 men and women. Added mass (weighted vest) simulated a 5% increase in body fat (BF%). Independent variables included BF%, thigh length, and static Q-angle (Q-angles), and while performing RVJ, different expressions of frontal-plane knee angle (FPKA), dynamic Q-angle (Q-angled), vertical ground reaction force (vGRF), concentric vertical impulse (Iz), concentric rate of force development (CRFD), and vertical power (Pz). Variables having significant (p ≤ 0.05) negative correlations with RVJ displacement included BF% (r = −0.76) and Q-angles (r = −0.55). Those having significant (p ≤ 0.05) positive correlations with RVJ displacement included peak and average concentric Pz (r range = 0.74–0.81), peak and average concentric vGRF (r range = 0.46–0.67), Iz (r range = 0.32–0.54), thigh length (r = 0.31), minimum Q-angled (r = 0.31), and maximum FPKA (r = 0.28). Variables not associated (p > 0.05) with RVJ displacement included minimum and excursion FPKA (r = 0.11 and 0.23), maximum, excursion, and average Q-angled (r = 0.24, 0.11, and 0.22), and CRFD (r range = 0.19–0.24). A simple regression model predicted RVJ displacement (p = 1.00) for the simulated 5% increase in body fat. To maximize jumping performance, (a) high levels of body fat should be avoided, (b) peak and average Pz, vGRF, and Iz should be maximized through training, and (c) having a lower Q-angles is associated with better jumping ability.
An Improvement of Chalet Management System
Authors: Lim Xue Ting , Lee Khai Loon
Published: January 2021

The constant growth of the tourism industry in Malaysia has led to the rise of the hospitality industry over recent years. The major tourism SMEs are usually providing the needs or demand of touristy to tourists such as food, accommodation, transportation and other necessities. This paper focuses on the issues of poor customer satisfaction and operational performance that occur in a small and medium scale hospitality company and the ways to solve the problem by developing a prototype of the Chalet Management System. The five whys analysis was used to identify the problems that occur in the hospitality company. The prototype of the Chalet Management System is developed by using Rapid Application Development (RAD) technique with Microsoft Access. This study showed that the Chalet Management System had improved customer satisfaction and operational performance by decreasing the registration process lead time and improving data accuracy and efficiency. The proposed system also received positive feedbacks with its functionalities from the company
A Linear Programming Model for Product Mix Profit Maximization in A Small Medium Enterprise Company
Authors: Mohd Baki Safwa , Cheng Jack Kie
Published: January 2021

Production planning is often challenging for small medium enterprises (SMEs) company. Most of the SMEs are having difficulty in determining the optimal level of the production output which can affect their business performance. Product mix optimization is one of the main key for production planning. Many company have used linear programming model in determining the optimal combination of various products that need to be produced in order to maximize profit. Thus, this study aims for profit maximization of a SME company in Malaysia by using linear programming model. The purposes of this study are to identify the current process in the production line and to formulate a linear programming model that would suggest a viable product mix to ensure optimum profitability for the company. ABC Sdn Bhd is selected as a case study company for product mix profit maximization study. Some conclusive observations have been drawn and recommendations have been suggested. This study will provide the company and other companies, particularly in Malaysia, an exposure of linear programming method in making decisions to determine the maximum profit for different product mix.
Effect of growth ring angle on lateral enlargement of compressed Cryptomeria japonica wood impregnated with polyethylene glycol
Authors: Mizoguchi Chikara , Sakagami Hiroki , Fujimoto Noboru , Nakao Tetsuya
Published: January 2021

The lateral enlargement perpendicular to the compressive direction for small thin boards of Cryptomeria japonica was investigated to evaluate the effects of density and compressive directions to the radial (plane-sawn board) and 45 degrees of tilt to the radial (45º sawn board). Samples were impregnated with 200 and 20,000 molecular weight polyethylene glycol (PEG). The enlargement perpendicular to the fiber direction with deformation was obtained for heartwood and sapwood specimens treated only with PEG20,000. The compression ratio of specimens treated with PEG 20,000 exceeded the void volumes regardless of the wood density. Enlarged specimens of both sapwood and heartwood showed the inflection points in the force-compression ratio curve and no correlation between the compressive directions and lateral enlargement of specimens. In the local area showing the largest deformation, however, a weak positive correlation from plane-sawn boards and weak negative correlation from 45º sawn boards between the angles of compressive direction to growth ring and lateral enlargement were derived. Microfocus X-ray computer tomography in these areas showed the different morphological compressive deformations. The cells in the 45º sawn board were forced out due to each cell moving, whereas the radially arranged ones in the plane sawn board buckled under compression.
Improving of the impregnability of refractory spruce wood by Bacillus licheniformis pretreatment
Authors: Yildiz Sibel , Canakci Sabriye , Yildiz Umit C. , Ozgenc Ozlem , Tomak Eylem D.
Published: January 2021

In this study it was aimed to improve impregnability of spruce (Picea orientalis L.) wood with bacteria (Bacillus licheniformis A1) pretreatment, using copper/chromium/arsenic Type C (CCA-C) andcopper azole Type A (CBA-A). The effects of Bacillus licheniformis A1 on weight loss, copper uptake, and compression strength of samples were determined. Weight loss was slightly changed by bacterial degradation in all test groups. The best copper uptake cases were 1466 ppm for CCA-C and 2730 ppm for CBA-A. Improvement on copper uptake with bacteria pretreatment was in a range of 18 to 103% compared to control samples. Compression strength was decreased by bacterial degradation. However strength losses might be acceptable for several construction applications. Bacillus licheniformis A1seems to havea good potential for increasing the permeability of spruce wood.
PENGARUH BAURAN PEMASARAN TERHADAP LOYALITAS KONSUMEN KECAP MANIS ABC DI JABODETABEK
Authors: Sa'adah Halimatus , Elpawati Elpawati , Puspita Sari Rizki Adi
Published: January 2021

Penelitian ini bertujuan untuk menganalisis efek dari bauran pemasaran terhadaployalitas konsumen. Sebanyak 100 responden diwawancarai terdiri dari konsumenyang pernah mengkonsumsi atau mengkonsumsi kecap ABC setidaknya sekaliselama setahun terakhir. Analisis deskriptif dan metode path digunakan untukmenganalisis hubungan antara variabel independen, yaitu produk, harga, tempat,dan promosi terhadap variabel dependen, loyalitas pelanggan (Y2) melaluimediasi variabel atau variabel perantara, perilaku konsumen (Y1). Hasil penelitianmenunjukkan bahwa variabel produk, harga, tempat, dan promosi bersama-samamemiliki pengaruh pada perilaku konsumen saat uji parsial menunjukkan bahwavariabel produk dan promosi memiliki efek langsung pada loyalitas konsumen,dan variabel harga dan tempat tidak memiliki pengaruh secara langsung tetapimelalui variabel perantara yaitu perilaku konsumen.
U.S. State Life Tables, 2018
Authors: Arias Elizabeth
Published: January 2021

National Vital Statistics Report; includes complete period life tables for each of the 50 states and the District of Columbia by sex based on age-specific death rates in 2018
DSTL: Solution to Limitation of Small Corpus in Speech Emotion Recognition
Authors: Chen Ying , Xiao Zhongzhe , Zhang Xiaojun , Tao Zhi
Published: January 2021

Traditional machine learning methods share a common hypothesis: training and testing datasets must be in a common feature space with the same distribution. However, in reality, the labeled target data may be rare, so that target space does not share the same feature space or distribution as an available training set (source domain). To address the mismatch of domains, we propose a Dual-Subspace Transfer Learning (DSTL) framework that considers both the common and specific information of the two domains. In DSTL, a latent common subspace is first learned to preserve the data properties and reduce the discrepancy of domains. Then, we propose a mapping strategy to transfer the sourcespecific information to the target subspace. The integration of the domain-common and specific information constructs the proposed DSTL framework. In comparison to the stateart-of works, the main contribution of our work is that the DSTL framework not only considers the commonalities, but also exploits the specific information. Experiments on three emotional speech corpora verify the effectiveness of our approach. The results show that the methods which include both domain-common and specific information perform better than the baseline methods which only exploit the domain commonalities.
Female Urethral Disease: A Contemporary Review of Presentation, Diagnosis and Current Management Strategies
Authors: Z : Cope , C Anglin , A Dryden , J Hawthorne , KBY Choi
Published: January 2021

Background: Female urethral diseases are sparsely discussed within the literature when compared to urethral diseases affecting men. While, the male urethra is impacted more frequently secondary to the comparative increase in average length, presence of the prostate and considerations of carrying genetic material-disease process of the female urethra impose significant distress to affected patients and also potential for malignancy. The clinical presentation and management strategies often differs from the male counterpart and therefore it is important to consider disease processes of the female urethra unto their own right for evaluation and successful management. It is to that end this publication is put forth.
Reconstruction of Nasal Subunits using a Nasolabial Flap: Case Report
Authors: C Montufar , VA Ugalde , CB Kushida
Published: January 2021

Nasal reconstruction is a broad and diverse topic that encompasses multiple scenarios as well as various repair techniques. The ala nasi is considered a cosmetic unit that represents a challenge for the surgeon, both in its functional and aesthetic reconstruction.
The Manufacturer’s Deliberate Modification of the Shell Structure of the BellaGel® SmoothFine in Violation of the Regulatory Requirement
Authors: JH Kim
Published: January 2021

The BellaGel® SmoothFine (HansBiomed Co. Ltd., Seoul, Korea) is the only fifth-generation of a silicone gel-filled breast implant from a Korean manufacturer. The BellaGel® SmoothFine with a 5-layered shell structure was approved for clinical use, but the manufacturer deliberately modified the shell structure in violation of the regulatory requirement of the Korean Ministry of Food and Drug Safety. This was hidden by both plastic surgeons and the manufacturer. With the use of high-resolution ultrasound, however, we confirmed that both 4-layered and 5-layered devices were circulated in the Korean market. Further investigations are warranted to disclose a relationship between plastic surgeons and the manufacturer.
¿Qué puedo esperar del futuro?
Authors: Aranda Fraga Fernando
Published: January 2021

Autoridades presentes, directivos, docentes, personal de apoyo y alumnos de la Universidad Adventista del Plata, padres y demás familiares de graduandos, y especialmente queridos graduandos de la actual promoción.

Hace poco más de un par de siglos, quien fuera el más relevante y revolucionario pensador de la edad moderna, Emanuel Kant, expresó mediante tres preguntas lo que para él condensaba el sentido de la vida humana: ¿qué debo hacer?, ¿qué puedo saber?, ¿qué me cabe esperar?, cuestiones fundamentales de la existencia que, según él, podían resumirse en una sola: ¿qué es el hombre? La ética, la epistemología y la religión son las disciplinas encargadas de responder esas tres primeras preguntas, en tanto que de la última se ocupa la antropología.

Les propongo situarnos en el marco de estas tres preguntas kantianas para analizar desde ese lugar lo que muy posiblemente han llegado a ser ustedes al cabo de su primera formación académica universitaria, mientras están en la antesala del mundo profesional. Para ello invertiré un tanto el orden de las preguntas de Kant, abordando primeramente el tema del conocimiento.

Sin lugar a dudas, durante estos años que has pasado en la Universidad has aprendido muchas cosas, y al mismo tiempo también serás consciente de que parte de esos conocimientos han de quedar obsoletos dentro de unos años. Esto es así, no porque hayas aprendido contenidos viejos, no te asustes, seguramente están muy actualizados, sino simplemente porque el ritmo vertiginoso en que se mueve actualmente la ciencia, y la transformación del mundo como efecto de ésta, no tienen tregua y es siempre exponencialmente superior al periodo que le precede. Habrás escuchado, no pocas veces, que mientras vas pasando por la universidad, como dijera Ortega y Gasset, “es mucho más importante el camino que la posada”. Esto es, importa más el aprendizaje de métodos y procedimientos con los cuales logres obtener tus conocimientos y sepas resolver problemas, pues ello te permitirá actualizarte permanentemente y desentenderte de ideas y conceptos que van perdiendo sentido y utilidad en la vida real. Pero esto, de ninguna manera significa que debamos evitar o rechazar los contenidos, no existe aprendizaje en el vacío, sino simplemente ser capaces de separarlos entre accesorios y fundamentales, transitorios, es decir, temporales, y perdurables, o hasta incluso eternos. Semejante incorporación de conceptos te capacita para darle sentido a tu vida, a tu profesión y a tu deambular por el mundo. Ahora bien, ¿hay ideas o conceptos que hoy puedas juzgar como fundamentales y perdurables en el tiempo? ¿Te habremos preparado en ésta, tu Universidad, para que, estando a minutos de egresar de ésta, hoy alcances a discernirlos con corrección y precisión, sin temor a equivocarte? Te propongo realizar un breve ejercicio con el fin de evaluarlos y revisarlos.
Burnout académico en estudiantes universitarios peruanos
Authors: Estrada Araoz Edwin Gustavo , Gallegos Ramos Néstor Antonio , Mamani Uchasara Helen Juddy
Published: January 2021

La presente investigación tuvo como objetivo describir el burnout académico de los estudiantes de la carrera profesional de Educación de una universidad pública de Madre de Dios (Perú). El enfoque de investigación fue cuantitativo, el diseño no experimental, y de tipo descriptivo-transeccional. La muestra fue conformada por 202 estudiantes a quienes se les aplicó un cuestionario de datos sociodemográficos y académicos así como el Cuestionario Maslach Burnout Inventory Student Survey (MBI-SS), instrumento con adecuados niveles de validez y confiabilidad. Los hallazgos indican que los estudiantes se caracterizan por presentar niveles moderados de burnout académico y se determinó que algunas variables como el sexo, el grupo etario, la situación laboral y el año de estudio se asocian significativamente con el burnout académico. Finalmente se concluyó que es necesario que se diseñen y ejecuten programas que desarrollen los factores protectores de los estudiantes para que puedan afrontar adecuadamente situaciones adversas y estresantes y se disminuya así la prevalencia del burnout académico.
Diseño y validez de contenido de una rúbrica analítica socioformativa para evaluar competencias investigativas en posgrado
Authors: Aliaga Pacora Alicia Agromelis , Juárez Hernández Luis Gibran , Herrera Meza Raúl
Published: January 2021

En la presente investigación, se diseñó y validó en contenido un instrumento para evaluar competencias investigativas en posgrado. Para su diseño se integraron aspectos evidenciados en el desarrollo del trabajo de tesis. El instrumento fue revisado por cuatro expertos para el análisis de validez de facie y para el análisis de validez de contenido se efectuó un juicio de expertos. Concluidas estas fases se realizó un pilotaje del instrumento con 38 asesores para evaluar el grado de comprensión de instrucciones e ítems, así como la confiabilidad del instrumento. El instrumento se diseñó como rúbrica analítica socioformativa integrando cinco aspectos del desarrollo del trabajo de tesis a través de 11 ítems y para cada uno de ellos cinco niveles de desempeño con un descriptor propio. Los expertos expresaron sugerencias de redacción para optimizar la rúbrica. Los jueces expertos validaron en contenido los ítems (V de Aiken>0.80; VI del IC al 95%>0.75). El pilotaje mostró un buen grado de comprensión de las instrucciones e ítems y relevancia de las preguntas y se determinó que el instrumento posee confiabilidad (Alfa de Cronbach: 0.832). Se presenta un instrumento válido en contenido, sin embargo, se requiere proseguir con el análisis de sus propiedades psicométricas (validez de constructo y confiabilidad).
Ética y TIC: Algunas reflexiones sobre el rol de los educadores
Authors: Bustos Canales Karla
Published: January 2021

El propósito de este trabajo es reflexionar sobre la implicancia de la Ética en las Tecnologías de la Información y de la Comunicación (TIC) en contextos de aprendizaje escolar. En primer lugar, se identifican algunos problemas relevantes en el uso de las herramientas tecnológicas, esto es, precisar aquellas dificultades que requieren de la supervisión y orientación de un educador. Luego, se enfatiza en la necesidad de actualizar los protocolos que regulan las conductas y los comportamientos de los usuarios en la red, especialmente, cuando participan comunidades educativas conformadas por niños y adolescentes. Finalmente, se entregan algunas orientaciones pertinentes a la redacción de protocolos que reglamenten las conductas del estudiantado en el espacio digital.
Esquemas desadaptativos tempranos y bienestar psicológico en pacientes que acuden a consulta externa en una Institución Prestadora de Servicios de Salud – IPRESS, Lima, 2020
Authors: Monteza Vásquez Segundo Alamiro , Yogui Takaesu Daniel Noboru
Published: January 2021

En el presente estudio se planteó como objetivo determinar la relación entre los esquemas desadaptativos tempranos y el bienestar psicológico de los pacientes que acuden a consulta externa en una Institución Prestadora de Servicios de Salud – IPRESS, Lima, 2020. La investigación se desarrolló bajo un enfoque cuantitativo, diseño no experimental y un alcance correlacional; en la cual participaron 120 pacientes (ambos sexos) que acudieron al servicio consulto externa de una Institución Prestadora de Servicios de Salud – IPRESS de la ciudad de Lima. La recolección de datos se realizó utilizando dos instrumentos: Escala de esquemas de Young (YSQ-SF) y la Escala de Bienestar psicológico Bieps-A. En el estudio se concluyó que los esquemas desadaptativos tempranos presentan una relación significativa (p=0,000) e inversa (r=-0,764) con el bienestar psicológico en pacientes que acuden a consulta externa en una IPRESS, Lima, 2020. Es decir a mayor presencia de esquemas desadaptativos, los pacientes tienden a experimentar menores niveles de bienestar psicológico.
El misterio del poder en el pensamiento de N.A. Berdyaev: Un estudio literario y filosófico
Authors: Usachev Aleksandr V
Published: January 2021

El propósito de este artículo es replantear la cuestión del poder y su esencia en el contexto de cómo lo ve la filosofía religiosa rusa, en este caso, N. A. Berdyaev. Sus reflexiones cobran relevancia porque plantea el problema en un sentido universal, vinculándolo con la esencia del hombre y los hechos históricos que lo rodean. La ontología histórica se revela en la filosofía del pensador ruso como un misterio infinito, cuyas definiciones racionales son muy difíciles. La metodología de este trabajo está tomada de los trabajos del programa sobre la historia de la filosofía rusa de V. V. Zenkovsky y N. O. Lossky y consiste en crear una base comparativa para comparar los principales conceptos de poder en la filosofía occidental y la filosofía rusa. Incluso un análisis aproximado muestra que el gobierno elude el discurso y evita las definiciones racionales, de lo contrario sería posible explicar la revolución en Rusia por su carácter fundamental. El material del artículo puede ser utilizado en estudios sociales y antropológicos del poder, lo que aumenta y extiende su influencia incluso a las relaciones más simples pero en lugar de reducirla. Los creadores de nuevas épocas siempre enfrentan un nuevo tipo de responsabilidad en el sentido de que son responsables ante las generaciones vivas de cómo usan el poder y si es para bien o para mal.
Nuevos escenarios para la estrategia de desarrollo universitario en el espacio educativo internacional
Authors: Mamedov Agamali K. , Lipatova Maria E. , Korkiya Eka D.
Published: January 2021

El objetivo de esta investigación fue mostrar cómo diversos enfoques para comprender el papel, el lugar y la misión de la universidad han sufrido cambios en el contexto de la retrospectiva histórica y la sociedad moderna. La base metodológica del estudio son los trabajos clásicos y modernos de científicos y especialistas rusos y extranjeros, los métodos de generalización y análisis teóricos, el método de sistematización, el análisis interdisciplinario y comparativo de trabajos sociológicos, filosóficos, culturales y económicos en el campo de la educación superior. educación, y evaluaciones de expertos y análisis de los datos secundarios. Como resultado, se identificaron las principales tendencias en el desarrollo de las universidades y los determinantes socioculturales de la transformación de las universidades. Se analizó la erosión de los formatos universitarios tradicionales y la transición a formas digitales de comunicación educativa y científica. A pesar de las transformaciones socioculturales actuales y la aparición de nuevos modelos de universidad, la universidad resuelve sus principales tareas de formar una persona pensante y formar especialistas de alto nivel. Sin embargo, estos procesos obligan a la universidad a revisar las estructuras y principios tradicionales de existencia, así como a estar más atenta al proceso de incremento de nuevos conocimientos e información, para no caer en los extremos de quedarse exclusivamente en la educación o la ciencia.