RESUMEN
In order to address labor shortages, starting April 2019 the Japanese government introduced two new visa categories, and it can be expected that the growing number of foreign residents living and working in Japan will be increasing further in the foreseeable future. Within this context, the notion of Yasashii Nihongo or Simplified Japanese has been gaining attention over recent years. Originally designed as a tool for transmitting information in disaster-related situations and proposed for disaster mitigation purposes, at present it is being advocated as a means of communication to be used in non-disaster situations as well. The authors argue that ultimately Yasashii Nihongo for non-disaster situations may be just a means to an end. Seen from the perspective of "reasonable accommodation", a concept prevalent in the domain of disability studies, they assert that by de facto creating a new linguistic category making it a tacit prerequisite to communicate in "Japanese only", Yasashii Nihongo is but a concept geared towards the language majority (speakers using Japanese as their first language) and is potentially serving no other purpose than to alleviate the psychological burden of having to speak in a language other than Japanese, thus potentially leading to a new form of discrimination towards language minorities. Offering an alternative approach for improving multicultural communication aimed at establishing a communicative space based on openness, equality, and mutual respect for each other's cultural, linguistic and ethnic identities, the authors propose the introduction of language education based on the notion of plurilingualism, as outlined in the Common European Framework of Reference for Languages (CEFR) by the Council of Europe.
Asunto(s)
Lenguaje , Lingüística , Comunicación , Europa (Continente) , JapónRESUMEN
The vast majority of light-emitting diode and liquid-crystal displays, solar panels, and windows in residential and industrial buildings use glass panels owing to their high mechanical stability, chemical resistance, and optical properties. Glass surfaces reflect about 4-5% of incident light if no antireflective coating is applied. In addition to energy losses in displays, surface reflections diminish picture quality. Engineering of antireflective coatings can be beneficial for all types of glass screens, specifically for large screens and touch-screen devices when scratch-resistance and self-cleaning properties of the glass surface are also desired. A scalable and robust approach to produce antireflective coatings for glass surfaces with desired optical and mechanical properties is introduced in this work. The developed coating mimics the structure of a moth-eye cornea. The coating is a subwavelength-microstructured thin layer on the glass surface made of a monolayer of hemispherical silica nanoparticles obtained by hydrothermal fusion of spherical particles to the glass substrate. The sequence of the particle deposition in the layer-by-layer process is adjusted to balance attractive-repulsive interactions among nanoparticles and between the nanoparticles and the glass surface to generate coatings with a high surface coverage of up to 70%, which exceeds the 54.7% limit of the random sequential addition model. This level of surface coverage allows for a combination of properties beneficial for the described applications: (i) an average reflectance of 0.5 ± 0.2% for a visible and near-infrared optical spectrum, (ii) an improved mechanical stability and scratch resistance, and (iii) non-wetting behavior.
RESUMEN
This work introduces a gravity fiber drawing (GFD) method of making single filament nanofibers from polymer solutions and precise alignment of the fibers in 3D scaffolds. This method is advantageous for nanofiber 3D alignment in contrast to other known methods. GFD provides a technology for the fabrication of freestanding filament nanofibers of well-controlled diameter, draw ratio, and 3D organization with controllable spacing and angular orientation between nanofibers. The GFD method is capable of fabricating complex 3D scaffolds combining fibers with different diameters, chemical compositions, mechanical properties, angular orientations, and multilayer structures in the same construct. The scaffold porosity can be as high as 99% to secure transport of nutrients and space for cell infiltration and differentiation in tissue engineering and 3D cell culture applications.
RESUMEN
We studied NE-4C neural cells differentiation on 2D polycaprolactone (PCL) nanofibrous scaffolds with systematically varied mechanical characteristics of nanofibers while retaining an unchanged fiber alignment, diameter, and chemical composition. Our experiments demonstrated that the nanofibers with enhanced mechanical properties are beneficial for the preferential development of neuronal cells vs. glial cells. Electrospun (ES) and touch-spun (TS) nanofibers were fabricated with Young's modulus in the range of 10 MPa to 230 MPa and a fraction of crystallinity from 30% to 80%. The TS fibers undergo a greater drawing ratio and thus approach a greater polymer chain stretching and alignment that resulted in an increased crystallinity. The TS scaffolds demonstrated improved stability in the aqueous cell culture environment, resisting misalignment and entanglement after a period of 2 weeks of swelling followed by 14 days of neural differentiation. The results confirmed that the neurites on the TS fibers have a preferred orientation even after swelling.
Asunto(s)
Nanofibras/química , Andamios del Tejido/química , Animales , Diferenciación Celular/fisiología , Humanos , Células-Madre Neurales/citología , Células-Madre Neurales/metabolismo , Poliésteres/química , Polímeros/química , Ingeniería de Tejidos/métodosRESUMEN
In the current study, we examined the potential for neural stem cell (NSCs) proliferation on novel aligned touch-spun polycaprolactone (PCL) nanofibers. Electrospun PCL nanofibers with similar diameter and alignment were used as a control. Confocal microscopy images showed that NSCs grew and differentiated all over the scaffolds up to 8 days. Neurite quantification analysis revealed that the NSCs cultured on the touch-spun fibers with incorporated bovine serum albumin promoted the expression of neuron-specific class III ß-tubulin after 8 days. More importantly, NSCs grown on the aligned touch-spun PCL fibers exhibited a bipolar elongation along the direction of the fiber, while NSCs cultured on the aligned electrospun PCL fibers expressed a multipolar elongation. The structural characteristics of the PCL nanofibers analyzed by X-ray diffraction indicated that the degree of crystallinity and elastic modulus of the touch-spun fiber are significantly higher than those of electrospun fibers. These findings indicate that the aligned and stiff touch-spun nanofibrous scaffolds show considerable potential for nerve injury repair.
Asunto(s)
Nanofibras/química , Regeneración Nerviosa/fisiología , Tacto , Animales , Materiales Biocompatibles/química , Diferenciación Celular , Humanos , Nanofibras/ultraestructura , Células-Madre Neurales/citología , Poliésteres/química , Propiedades de SuperficieRESUMEN
OBJECTIVE: The aim of this study was to assess the magnitude of changes in nutritional body composition components as a consequence of rheumatoid arthritis (RA) and the extent to which these components are associated with RA clinical characteristics, serologic markers, and osteoporosis-related phenotypes (OP-RPs). Early pathologic signs, if detected, could assist in future preventative techniques. METHODS: The study sample was comprised of 260 women with RA and 168 first-degree female relatives without RA who returned for body composition measurements using bioelectrical impedance analysis, from a previously established epidemiologic study conducted in Kazakhstan. RESULTS: In multivariate logistic regression, body composition components, the fat mass index (odds ratio [OR], 0.848; 95% confidence interval [CI], 0.786-0.913; P < 0.001) and the phase angle (PA; OR, 0.654; 95% CI, 0.467-0.826; Pâ¯=â¯0.001), were independently and significantly negatively associated with RA after disease development. In multilinear regression analysis, PA was consistently associated with OP-RP, specifically concerning the spongial bone mineral density (BMDSPN) and cortical index, where ageing, reduced PA and increased disease duration explained 31.5% of BMDSPN and 37.3% of cortical index variation. CONCLUSION: Data on RA in women in Kazakhstan consistently show that fat mass index and PA act as independent major covariates associated with RA affection status. These findings suggest exacerbated body composition deterioration when compared with healthy controls, potentially indicating the early appearance of sarcopenia and likely cachexic-like properties. The data also suggest that PA could serve as a potential predictor of RA prognosis, and the concomitant development of osteoporosis.
Asunto(s)
Artritis Reumatoide/complicaciones , Composición Corporal/fisiología , Caquexia/complicaciones , Osteoporosis/complicaciones , Sarcopenia/complicaciones , Adulto , Factores de Edad , Artritis Reumatoide/fisiopatología , Índice de Masa Corporal , Caquexia/fisiopatología , Estudios de Casos y Controles , Estudios Transversales , Femenino , Humanos , Persona de Mediana Edad , Osteoporosis/fisiopatología , Sarcopenia/fisiopatologíaRESUMEN
PURPOSE: We aimed to assess which of the major risk factors associated with rheumatoid arthritis (RA) severity are also associated with osteoporosis-related phenotypes (OP-RP) in the native population of Kazakhstan. METHODS: Four hundred six RA patients (90.6% females) with 397 controls-unaffected first-degree relatives were recruited. Biochemical factors were recorded, and OP-RP were assessed using QCT scans and ultrasound densitometry (US) of the forearm to estimate cortical indices (CI), spongial bone mineral density (BMDSPN), and US_T-scores. RESULTS: In the RA affected female population, ~ 80% suffered from osteopenia or osteoporosis. All OP-RP were negatively correlated with age and female's sex, as expected, and thus accordingly adjusted, resulting in consistent, significantly [p = 0.016 (CI), p < 0.0001 (both BMDSPN and US_T-scores)] lower OP-RP estimates in affected females. Using multiple regression analysis for OP-RP manifestations, only age and disease duration appeared consistently associated with all three studied phenotypes, while menopause status or years following the onset of menopause were also significant for BMDSPN and US_T-scores. However, when disease duration was examined, we found that it was significantly dependent on morning stiffness, ESR, total cholesterol levels, weight, and menopause status, which explains 38.6% of the disease duration. CONCLUSIONS: Approximately 80% of female RA patients suffer from osteoporosis or osteopenia in the study group, which appears from a young age. RA disease duration is the major risk factor for OP-RP deterioration, especially as assessed by BMDSPNG, and US_T-scores. As a result, all OP-RP demonstrate significantly lower levels in comparison to sex- and age-matched unaffected individuals.
Asunto(s)
Artritis Reumatoide/epidemiología , Enfermedades Óseas Metabólicas/epidemiología , Osteoporosis/epidemiología , Absorciometría de Fotón/métodos , Adulto , Anciano , Artritis Reumatoide/complicaciones , Artritis Reumatoide/diagnóstico por imagen , Densidad Ósea , Enfermedades Óseas Metabólicas/etiología , Femenino , Antebrazo/diagnóstico por imagen , Humanos , Kazajstán/epidemiología , Masculino , Menopausia , Persona de Mediana Edad , Osteoporosis/etiología , Factores de Riesgo , Índice de Severidad de la Enfermedad , Factores Sexuales , Factores de Tiempo , Adulto JovenRESUMEN
A growing body of empirical evidence now supports a negative association between dark traits in leaders and the psychological health of employees. To date, such investigations have mostly focused on psychopathy, nonspecific measures of psychological wellbeing, and have not considered the mechanisms through which these relationships might operate. In the current study (N = 508), we utilized other-ratings of personality (employees rated leaders' personality), psychometrically robust measures, and sophisticated modeling techniques, to examine whether the effects of leaders' levels of narcissism and psychopathy on employee depression are mediated by workplace bullying. Structural equation models provided clear evidence to suggest that employee perceptions of both leader narcissism and psychopathy are associated with increased workplace bullying (25.8% and 41.0% variance explained, respectively) and that workplace bullying fully mediates the effect of leader narcissism and psychopathy on employee depression (21.5% and 20.8% variance explained, respectively). However, when psychopathy and narcissism were modeled concurrently, narcissism did not explain any variance in bullying, suggesting that it is the overlap between psychopathy and narcissism, namely, the "dark core," which primarily accounts for the observed effects. We examined this assertion empirically and explored the unique effects of the subfactors of psychopathy. (PsycINFO Database Record
Asunto(s)
Trastorno de Personalidad Antisocial/psicología , Acoso Escolar , Depresión , Liderazgo , Adulto , Femenino , Humanos , Masculino , Modelos Psicológicos , Narcisismo , PersonalidadRESUMEN
Robust, simple, and scalable touch- and brush-spinning methods for the drawing of nanofibers, core-shell nanofibers, and their aligned 2D and 3D meshes using polymer solutions and melts are discussed.
Asunto(s)
Nanofibras/química , Animales , Materiales Biocompatibles/química , Materiales Biocompatibles/farmacología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Ratones , Microscopía Confocal , Microscopía Electrónica de Rastreo , Nanofibras/toxicidad , Polietilenglicoles/químicaRESUMEN
Reactive spinning of nano- and microfibers that involves very fast chemical reactions and ion exchange is a challenge for the common methods for nanofiber formation. Herein, we introduce the reactive magnetospinning method. This procedure is based on the magnetic-field-directed collision of ferrofluid droplets with liquid droplets that contain complementary reactants. The collision, start of the chemical reaction, and the fiber drawing are self-synchronized. The method is used to synthesize, cross-link, and chemically modify fiber-forming polymers in the stage of fiber formation. The method provides new opportunities for the fabrication of nanofibers for biomedical applications.
RESUMEN
Magnetospinning is a new method for spinning of continuous micro- and nano-fibers using a permanent revolving magnet. The method utilizes magnetic forces and the hydrodynamic features of stretched threads to produce highly loaded, fine magnetic nanofibers. The magnetospinning process is independent of the solution dielectric properties and requires no high voltages, in contrast to the more-traditional electrospinning technique.
RESUMEN
Magnetic field assisted assembly is used to fabricate aligned single nanowire mesh-like nanostructured films. Inhomogeneous magnetic field is applied to translocate high aspect ratio silver nanowires from suspensions to the surface of solid supports. The tangential component of the magnetic field vector is rotated in two consecutive steps to arrange the rectangular mesh-like structure of orthogonally oriented nanowires with minimal fractions of loops and bent structures. This work demonstrates highly ordered nanowire films with superior properties to randomly deposited structures- specifically one order of magnitude greater conductivity and more than ten percent higher transparency. This method is simple, scalable and can be used for the directed assembly of magnetic and nonmagnetic highly ordered, percolated structures.
RESUMEN
In a non-uniform magnetic field, the droplets of colloids of nickel nanorods and nanobeads aggregate to form a cusp at the droplet surface not deforming the entire droplet shape. When the field is removed, nanorods diffuse away and the cusp disappears. Spherical particles can form cusps in a similar way, but they stay aggregated after the release of the field; finally, the aggregates settle down to the bottom of the drop. The X-ray phase contrast imaging reveals that nanorods in the cusps stay parallel to each other without visible spatial order of their centers of mass. The formation of cusps can be explained with a model that includes magnetostatic and surface tension forces. The discovered possibility of controlled assembly and quenching of nanorod orientation under the cusped liquid surface offers vast opportunities for alignment of carbon nanotubes, nanowires and nanoscrolls, prior to spinning them into superstrong and multifunctional fibers. Magnetostatic and electrostatic analogies suggest that a similar ideal alignment can be achieved with the rod-like dipoles subject to a strong electric field.
Asunto(s)
Magnetismo , Nanotubos de Carbono/química , Nanotubos/química , Coloides/química , Oro/química , Fenómenos Magnéticos , Nanocables/química , Propiedades de SuperficieRESUMEN
The enzymogel nanoparticle made of a magnetic core and polymer brush shell demonstrates a novel type of remote controlled phase-boundary biocatalysis that involves remotely directed binding to and engulfing insoluble substrates, high mobility, and stability of the catalytic centers. The mobile enzymes reside in the polymer brush scaffold and shuttle between the enzymogel interior and surface of the engulfed substrate in the bioconversion process. Biocatalytic activity of the mobile enzymes is preserved in the enzymogel while the brush-like architecture favors the efficient interfacial interaction when the enzymogel spreads over the substrate and extends substantially the reaction area as compared with rigid particles.
Asunto(s)
Biocatálisis , Celulasa/química , Enzimas Inmovilizadas/química , Geles/química , Nanopartículas/química , Resinas Acrílicas/química , Colorantes Fluorescentes/química , Concentración de Iones de Hidrógeno , Campos Magnéticos , Microscopía de Fuerza Atómica , Concentración Osmolar , Tamaño de la Partícula , Dióxido de Silicio/química , Propiedades de SuperficieRESUMEN
The perception of faces is often considered to be unique in comparison with that of other objects in the world. The fact that faces are processed not by their constituent components but by the spatial configuration between those components (holistic face processing--HFP) is often used to support this. Despite two decades of research, however, there is no consensus as to whether or not HFP is a process that is subject to attentional modulation. Here, in two experiments, we used a method to direct spatial attention not previously used in studies of HFP--an exogenous spatial cue--as it offers a robust, rapid, and involuntary method of directing attention. In one experiment we demonstrate that the degree of HFP afforded to a face is not reduced when attention is directed away from that face. In a second experiment we replicate this finding even when the face is simultaneously flanked by other faces--a condition under which a face-specific processing module would, hypothetically, be more sensitive to attentional guidance. These results add to the argument that HFP is carried out independently of attention.
Asunto(s)
Atención , Cara , Reconocimiento Visual de Modelos , Procesamiento Espacial , Discriminación en Psicología , Femenino , Humanos , Masculino , Psicofísica , Reconocimiento en Psicología , Adulto JovenRESUMEN
A drug-mimicking release process was triggered by a glucose signal resulting in the formation of a negative potential on an electrode modified with PQQ-dependent glucose dehydrogenase. This electrode was coupled with another electrode coated with an Fe(+3)-crosslinked alginate polymer film, which was dissolved upon formation of the negative potential releasing entrapped species.
Asunto(s)
Alginatos/química , Glucosa/química , Hierro/química , Técnicas Biosensibles , Técnicas Electroquímicas , Electrodos , Glucosa 1-Deshidrogenasa/química , Oro/química , Peroxidasa de Rábano Silvestre/química , Nanopartículas del Metal/química , Cofactor PQQ/químicaRESUMEN
It has been recently reported that for some suspensions of magnetic nanoparticles the transverse proton relaxation rate, R(2), is dependent on the time that the sample is exposed to an applied magnetic field. This time dependence has been linked to the formation of linear aggregates or chains in an applied magnetic field via numerical modeling. It is widely known that chain formation occurs in more concentrated ferrofluids systems and that this has an affect on the ferrofluid properties. In this work we examine the relationships between colloidal stability, the formation of these linear structures, and changes observed in the proton transverse relaxation rate of aqueous suspensions of magnetic particles. A series of iron oxide nanoparticles with varying stabilizing ligand brush lengths were synthesized. These systems were characterized with dynamic light scattering, transmission electron microscopy, dark-field optical microscopy, and proton transverse relaxation rate measurements. The dark field optical microscopy and R(2) measurements were made in similar magnetic fields over the same time scale so as to correlate the reduction of the transverse relaxivity with the formation of linear aggregates. Our results indicate that varying the ligand length has a direct effect on the colloidal arrangement of the system in a magnetic field, producing differences in the rate and size of chain formation, and hence systematic changes in transverse relaxation rates over time. With increasing ligand brush length, attractive inter-particle interactions are reduced, which results in slower aggregate formation and shorter linear aggregate length. These results have implications for the stabilization, characterization and potentially the toxicity of magnetic nanoparticle systems used in biomedical applications.
Asunto(s)
Nanopartículas de Magnetita/química , Polietilenglicoles/química , Dihidroxifenilalanina/química , Compuestos Férricos/química , Luz , Magnetismo , Protones , Dispersión de Radiación , Suspensiones , Agua/químicaRESUMEN
We report on the development of a multifunctional magnetic rotator that has been built and used during the last five years by two groups from Clemson and Drexel Universities studying the rheological properties of microdroplets. This magnetic rotator allows one to generate rotating magnetic fields in a broad frequency band, from hertz to tens kilohertz. We illustrate its flexibility and robustness by conducting the rheological studies of simple and polymeric fluids at the nano and microscale. First we reproduce a temperature-dependent viscosity of a synthetic oil used as a viscosity standard. Magnetic rotational spectroscopy with suspended nickel nanorods was used in these studies. As a second example, we converted the magnetic rotator into a pump with precise controlled flow modulation. Using multiwalled carbon nanotubes, we were able to estimate the shear modulus of sickle hemoglobin polymer. We believe that this multifunctional magnetic system will be useful not only for micro and nanorheological studies, but it will find much broader applications requiring remote controlled manipulation of micro and nanoobjects.
Asunto(s)
Hemoglobina Falciforme/química , Campos Magnéticos , Nanotecnología , Nanotubos/química , Níquel/química , Reología , Humanos , Nanotecnología/instrumentación , Nanotecnología/métodos , Reología/instrumentación , Reología/métodosRESUMEN
In situ characterization of minute amounts of fluids that rapidly change their rheological properties is a challenge. In this paper, the rheological properties of fluids were evaluated by examining the behavior of magnetic nanorods in a rotating magnetic field. We proposed a theory describing the rotation of a magnetic nanorod in a fluid when its viscosity increases with time exponentially fast. To confirm the theory, we studied the time-dependent rheology of microdroplets of 2-hydroxyethyl-methacrylate (HEMA)/diethylene glycol dimethacylate (DEGDMA)-based hydrogel during photopolymerization synthesis. We demonstrated that magnetic rotational spectroscopy provides rich physicochemical information about the gelation process. The method allows one to completely specify the time-dependent viscosity by directly measuring characteristic viscosity and characteristic time. Remarkably, one can analyze not only the polymer solution, but also the suspension enriched with the gel domains being formed. Since the probing nanorods are measured in nanometers, this method can be used for the in vivo mapping of the rheological properties of biofluids and polymers on a microscopic level at short time intervals when other methods fall short.
Asunto(s)
Fenómenos Magnéticos , Nanotubos/química , Reología , Rotación , Análisis Espectral , Glicol de Etileno/química , Metacrilatos/química , Polimerizacion , Factores de Tiempo , ViscosidadRESUMEN
A reversible locking mechanism is established for the generation of anisotropic nanostructures by a magnetic field pulse in liquid matrices by balancing the thermal energy, short-range attractive and long-range repulsive forces, and dipole-dipole interactions using a specially tailored polymer shell of nanoparticles. The locking mechanism is used to precisely regulate the dimensions of self-assembled magnetic nanoparticle chains and to generate and disintegrate three-dimensional (3D) nanostructured materials in solvents and polymers.