Mechanical properties of micro- and nanocapsules: Single-capsule measurements

AbstractCapsules of micron and sub-micron dimensions are abundant in nature in the form of bacterial or viral capsids and play an increasing role in modern technology for encapsulation and release of agents. The capsules' mechanical properties are of great importance in this context not only for stability but as well for transport properties in flow, rheology or adhesion. Thus, techniques that allow for single-capsule mechanical characterization have caught much attention recently and we summarize experimental developments in this field as well as theoretical background of capsule deformation with special attention to small deformation measurements. Deformation studies on polyelectrolyte multilayer capsules are introduced as a case study, since they can be tailored in their geometry and composition and are thus well-suited as a model system

INTERNALISASI AJARAN PANCA DHARMA TAMANSISWA, KEMAMPUAN SELF-REGULATED LEARNING, DAN PRESTASI AKADEMIK MAHASISWA

This study focuses on two factors that might correlate with the academic achievement of Sar-janawiyata Tamansiswa (UST) students. These two factors are the internalization of the teachings of the five Dharma Tamansiswa and the ability of self-regulated learning. Academic achievement is a benchmark of student success in each semester or at the end of the lecture period (graduation). Academic achievement is a result that can be fought for by all students in accordance with the tar-gets to be achieved respectively. The purpose of this study is to reveal whether the internalization of the teachings of the five Taman dharma Tamanasiswa and self-regulated leaning abilities corre-late with student academic achievement. The research process starts from curiosity and concern for UST students' academic achievement. Academic achievement is the result of evaluating whether the student is successful or not in each semester. This research is a Quantitative Regression Corre-lation research using a survey method for distributing attitudes and or behavioral scales. The scale is a psychological measurement tool to assess individuals in attitude and action. The scale is a de-scription of students on the variable internalization of the teaching of the five dharma and the abil-ity of self-regulated learning. While academic achievement can be seen from the results of student GPA.Keywords: Internalization of the teaching of the five dharma tamansiswa, self-regulated learning and Student Academic Achievement

The influence of plasma treatment on the elasticity of the in situ oxidized gradient layer in PDMS: towards crack-free wrinkling

Controlled surface wrinkling is widely applied for structuring surfaces in the micro- and nano-range. The formation of cracks in the wrinkling process is however limiting applications, and developing approaches towards crack-free wrinkles is therefore vital. To understand crack-formation, we systematically characterized the thickness and mechanics of thin layers formed by O2-plasma-oxidation of polydimethyl siloxane (PDMS) as a function of plasma power and pressure using Atomic Force Microscopy Quantitative Nano-mechanical Mapping (AFM-QNM). We found a nearly constant layer thickness with simultaneously changing Young's moduli for both power and pressure screenings. We determined the respective crack densities, revealing conditions for crack-free wrinkling. Thus we could identify correlations between the intensity of plasma treatment and the cracking behavior. The primary cause for crack-suppression is a continuous elasticity gradient starting within the soft bulk PDMS, and rising up to several hundred MPa at the oxidized layer's surface. With mechanical simulations via the Finite Elements Method (FEM) we were able to demonstrate a noticeable difference in maximal stress intensity σmax between a comparable, but theoretical single layer and a gradient interface. A threshold in tensile stress of σcrit = 14 MPa distinguishes between intact and cracked layers

Janus particles: from concepts to environmentally friendly materials and sustainable applications

Janus particles represent a unique group of patchy particles combining two or more different physical or chemical functionalities at their opposite sides. Especially, individual Janus particles (JPs) with both chemical and geometrical anisotropy as well as their assembled layers provide considerable advantages over the conventional monofunctional particles or surfactant molecules offering (a) a high surface-to-volume ratio; (b) high interfacial activity; (c) target controlling and manipulation of their interfacial activity by external signals such as temperature, light, pH, or ionic strength and achieving switching between stable emulsions and macro-phase separation; (d) recovery and recycling; (e) controlling the mass transport across the interface between the two phases; and finally (f) tunable several functionalities in one particle allowing their use either as carrier materials for immobilized catalytically active substances or, alternatively, their site-selective attachment to substrates keeping another functionality active for further reactions. All these advantages of JPs make them exclusive materials for application in (bio-)catalysis and (bio-)sensing. Considering “green chemistry” aspects covering biogenic materials based on either natural or fully synthetic biocompatible and biodegradable polymers for the design of JPs may solve the problem of toxicity of some existing materials and open new paths for the development of more environmentally friendly and sustainable materials in the very near future. Considering the number of contributions published each year on the topic of Janus particles in general, the number of contributions regarding their environmentally friendly and sustainable applications is by far smaller. This certainly pinpoints an important challenge and is addressed in this review article. The first part of the review focuses on the synthesis of sustainable biogenic or biocompatible Janus particles, as well as strategies for their recovery, recycling, and reusability. The second part addresses recent advances in applications of biogenic/biocompatible and non-biocompatible JPs in environmental and biotechnological fields such as sensing of hazardous pollutants, water decontamination, and hydrogen production. Finally, we provide implications for the rational design of environmentally friendly and sustainable materials based on Janus particles. [Figure not available: see fulltext.]. © 2020, The Author(s)

Plasmonic Properties of Colloidal Assemblies

The assembly of metal nanoparticles into supracolloidal structures unlocks optical features, which can go beyond synergistic combinations of the properties of their primary building units. This is due to inter-particle plasmonic coupling effects, which give rise to emergent properties. The motivation for this progress report is twofold: First, it is described how simulation approaches can be used to predict and understand the optical properties of supracolloidal metal clusters. These simulations may form the basis for the rational design of plasmonic assembly architectures, based on the desired functional cluster properties, and they may also spark novel material designs. Second, selected scalable state-of-the-art preparative strategies based on synthetic polymers to guide the supracolloidal assembly are discussed. These routes also allow for equipping the assembly structures with adaptive properties, which in turn enables (inter-)active control over the cluster optical properties. © 2021 The Authors. Advanced Optical Materials published by Wiley-VCH Gmb

The role of pH, metal ions and their hydroxides in charge reversal of protein-coated nanoparticles

In this study, we investigated charge inversion of protein-coated Au nanoparticles caused by the addition of metal ions. The addition of hydrolyzable metal ions (Lewis acids) can induce drastic pH changes and depending on this pH, the metal ions (e.g. M3+) are readily converted into the hydrolyzed species (MOH2+, M(OH)2+) or even into hydroxides (M(OH)3). Adsorbed metal hydroxides were identified to cause the charge inversion of the NPs by using a combination of cryo-TEM, EFTEM and ζ-potential measurements

From microfluidics to hierarchical hydrogel materials

Over the past two decades, microfluidics has made significant contributions to material and life sciences, particularly via the design of nano-, micro- and mesoscale materials such as nanoparticles, micelles, vesicles, emulsion droplets, and microgels. Unmatched in control over a multitude of material parameters, microfluidics has also shed light on fundamental aspects of material design such as the early stages of nucleation and growth processes as well as structure evolution. Exemplarily, polymer hydrogel particles can be formed via microfluidics with exact control over size, shape, functionalization, compartmentalization, and mechanics that is hardly found in any other processing method. Interestingly, the utilization of microfluidics for material design largely focuses on the fabrication of single entities that act as reaction volume for organic and cell-free biosynthesis, cell mimics, or local environment for cell culturing. In recent years, however, hydrogel design has shifted towards structures that integrate a large variety of functions, e.g., to address the demands for sensing tasks in a complex environment or more closely mimicking architecture and organization of tissue by multiparametric cultures. Hence, this review provides an overview of recent literature that explores microfluidics for fabricating hydrogel materials that go well beyond common length scales as well as the structural and functional complexity of microgels necessary to produce hierarchical hydrogel structures. We focus on examples that utilize microfluidics to design microgel-based assemblies, on microfluidically made polymer microgels for 3D bioprinting, on hydrogels fabricated by microfluidics in a continuous fashion, like fibers, and on hydrogel structures that are shaped by microchannels

SELF REGULATED LEARNING DITINJAU DARI EFIKASI DIRI SISWA: SELF REGULATED LEARNING REVIEWED FROM STUDENT SELF EFFICATION

Introduction: This is a study of improved quality of learning that comes to some of the factors called self-regulated learning and self-effication.Method: The research method was done with quantitative research methods with filling the Self Effication Scale and the Self-Learning Scale. The study participants were 120 around 11-15 year-old youths in three secondary schools in yogyakarta.Result: Results based on regression analysis showed that self-effication predicts the ability of self regulated learning. The two independent variables contribution amounts to 10,6% on dependent variables.Conclusion: Discussion of this study could be said that self-effication capabilities predict the abilities of self-regulated learning. Junior high school students realized their ability would make it easier to reform youth learning activities. Keyword: Self Efication, Self Regulated Learning ABSTRAK Pendahuluan Penelitian ini adalah penelitian mengenai tentang peningkatan kualitas belajar yang merujuk pada beberapa faktor yaitu self-regulated learning dan efikasi diri. Metode Penelitian ini dilakukan dengan metode penelitian kuantitatif dilakukan dengan pengisian skala efikasi diri dan Skala self regulated learning. Partisipan penelitian adalah 120 remaja berusia 11-15 tahun di tiga Sekolah Menengah Pertama di Yogyakarta. Hasil Berdasarkan analisis regresi menunjukan bahwa efikasi diri memprediksi kemampuan self-regulated learning. Kontribusi kedua variabel independen tersebut sebesar 10,6% pada variabel dependen. Kesimpulan dan Saran Pada penelitian ini dapat dikatakan bahwa kemampuan efikasi diri mampu memprediksi kemampuan self regulated learning. Remaja SMP menyadari akan kemampuan yang mereka miliki akan mempermudah dalam meregulasi kegiatan belajar remaja. Kata Kunci : Efikasi Diri, Self Regulated Learning

Efikasi Diri dan Keterlibatan Orangtua dalam Pendidikan dengan Self Regulated Learning

This study aimed at determining the improvement of the quality of students who refered to several factors, namely self-regulated learning, self-efficacy and parental involvement in Education using a quantitative research approach with the Self-Efficiency scale, the scale of parental involvement in education and the scale of self-regulated learning. In this study it could be said that the ability of self-efficacy and parent involvement in education were able to predict the ability of self-regulated learning. Junior high school students realized that their abilities were supported by parents who provided assistance in the learning process would make it easier to regulate teenage learning activities.Abstrak. Penelitian ini bertujuan untuk mengetahui peningkatan kualitas pebelajar yang merujuk pada beberapa faktor yaitu self-regulated learning, efikasi diri dan keterlibatan orangtua dalam Pendidikan dengan menggunakan pendekatan penelitian kuantitatif dengan skala Efikasi Diri, Skala keterlibatan orangtua dalam pendidikan dan Skala self regulated learning. Pada penelitian ini dapat dikatakan bahwa kemampuan efikasi diri dan Keterlibatan orangtua dalam pendidikan mampu memprediksi kemampuan self regulated learning. Remaja SMP menyadari akan kemampuan yang mereka miliki didukung oleh orangtua yang memberikan bantuan dalam proses belajar akan mempermudah dalam meregulasi kegiatan belajar remaja

Colloidal Self-Assembly Concepts for Plasmonic Metasurfaces

Metallic nanostructures exhibit strong interactions with electromagnetic radiation, known as the localized surface plasmon resonance. In recent years, there is significant interest and growth in the area of coupled metallic nanostructures. In such assemblies, short- and long-range coupling effects can be tailored and emergent properties, e.g., metamaterial effects, can be realized. The term “plasmonic metasurfaces” is used for this novel class of assemblies deposited on planar surfaces. Herein, the focus is on plasmonic metasurfaces formed from colloidal particles. These are formed by self-assembly and can meet the demands of low-cost manufacturing of large-area, flexible, and ultrathin devices. The advances in high optical quality of the colloidal building blocks and methods for controlling their self-assembly on surfaces will lead to novel functional devices for dynamic light modulators, pulse sharpening, subwavelength imaging, sensing, and quantum devices. This progress report focuses on predicting optical properties of single colloidal building blocks and their assemblies, wet-chemical synthesis, and directed self-assembly of colloidal particles. The report concludes with a discussion of the perspectives toward expanding the colloidal plasmonic metasurfaces concept by integrating them with quantum emitters (gain materials) or mechanically responsive structures. © 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei