Diverse Micro Research Articles

Structural Functions of 3D-Printed Polymer Scaffolds in Regulating Cell Fates and Behaviors for Repairing Bone and Nerve Injuries.

Tissue repair and regeneration, such as bone and nerve restoration, face significant challenges due to strict regulations within the immune microenvironment, stem cell differentiation, and key cell behaviors. The development of 3D scaffolds is identified as a promising approach to address these issues via the efficiently structural regulations on cell fates and behaviors. In particular, 3D-printed polymer scaffolds with diverse micro-/nanostructures offer a great potential for mimicking the structures of tissue. Consequently, they are foreseen as promissing pathways for regulating cell fates, including cell phenotype, differentiation of stem cells, as well as the migration and the proliferation of key cells, thereby facilitating tissue repairs and regenerations. Herein, the roles of structural functions of 3D-printed polymer scaffolds in regulating the fates and behaviors of numerous cells related to tissue repair and regeneration, along with their specific influences are highlighted. Additionally, the challenges and outlooks associated with 3D-printed polymer scaffolds with various structures for modulating cell fates are also discussed.

A Survey of Recent Developments in Magnetic Microrobots for Micro-/Nano-Manipulation.

Magnetically actuated microrobots have become a research hotspot in recent years due to their tiny size, untethered control, and rapid response capability. Moreover, an increasing number of researchers are applying them for micro-/nano-manipulation in the biomedical field. This survey provides a comprehensive overview of the recent developments in magnetic microrobots, focusing on materials, propulsion mechanisms, design strategies, fabrication techniques, and diverse micro-/nano-manipulation applications. The exploration of magnetic materials, biosafety considerations, and propulsion methods serves as a foundation for the diverse designs discussed in this review. The paper delves into the design categories, encompassing helical, surface, ciliary, scaffold, and biohybrid microrobots, with each demonstrating unique capabilities. Furthermore, various fabrication techniques, including direct laser writing, glancing angle deposition, biotemplating synthesis, template-assisted electrochemical deposition, and magnetic self-assembly, are examined owing to their contributions to the realization of magnetic microrobots. The potential impact of magnetic microrobots across multidisciplinary domains is presented through various application areas, such as drug delivery, minimally invasive surgery, cell manipulation, and environmental remediation. This review highlights a comprehensive summary of the current challenges, hurdles to overcome, and future directions in magnetic microrobot research across different fields.

Kinetic analysis and numerical tests of an adaptive car-following model for real-time traffic in ITS

Abundant real-time vehicle trajectory information provides an important guarantee for the driving safety and drivers’ decision-making in the intelligent transportation system (ITS), which improves the transport efficiency of traffic flow at the micro level. In this paper, we propose an adaptive car-following model to study the influence of the preceding vehicles’ information on the motion state of the target and the kinetic characteristics of traffic flow in the ITS, where the space headway, the velocity difference and the acceleration of preceding vehicles are considered simultaneously. According to the generalized diagram structure of road traffic, we mainly consider the two vehicles ahead and introduce adaptive parameters to control the proportion of different influencing factors. The rationality of the extended model is verified via real-world vehicle trajectory fitting experiments with the collected empirical data. Theoretical derivations are then carried out to describe the evolution of traffic flow under different scenarios, where the linear stability conditions and nonlinear analysis on small disturbance are included. Numerical tests are made to simulate the driving conditions and verify the accuracy of theoretical results. Computing the engine power of vehicles, we summarize the impact of traffic congestions and stop-and-go behaviors on the energy consumption. Diverse micro motion states and traffic flow dynamics can be revealed based on our car-following model, which will serve as both theoretical basis and experimental examples for the real-world traffic.

Spatiotemporally controlled emergence of nanoparticle microvortices under electric field

AbstractControlled assembly of nanoparticles (NPs) has garnered much interest over the past two decades. Beyond established techniques, new methods utilizing local short‐range or large‐scale long‐range interactions remain to be explored to achieve diverse micro‐ and nanoscale structures. Here, we report the controlled emergence of vortex‐pair arrays within monodispersed gold nanorods by applying a direct current electric field across a pair of sawtooth electrodes. By employing in situ darkfield microscopy and particle collective analysis, we elucidate the mechanism behind the formation and stabilization of the NP vortices, attributing it to the combined effects of the electrode shape, high NP density, and high solution viscosity. We further explore the controllability of the vortex‐pair arrays and obtain multiple complex vortice patterns. Our findings will facilitate the investigation of efficient and controlled dynamic assembly of NPs under external fields and help manufacture next‐generation optoelectronic functional materials.

Thinking beyond Ecology: Can Reskilling Youth Lead to Sustainable Transitions in Agri-Food Systems?

Green and decent work in the Global South is inextricably linked to sustaining rural livelihoods especially in agriculture that has undergone significant deskilling under the top-down, technocentric assemblages of the Green Revolution. Additionally, agrarian communities are also seeing youth quitting farming occupations in search of better livelihood options. Scholarly attention to green transitions though has been largely limited to the ecological dimensions. Enacting futures with a focus on ecologically responsible livelihoods need to go beyond existing narratives of technocentric and economic change and foreground the diverse micro institutional innovations that offer newer framings of reskilling. The growing evidence of agroecological initiatives across India indicates less discussed stories of transformation and innovations. Recognising the processes and linkages that allow for, and hinder, transformations at multiple scales and organisational levels is crucial for designing transformative initiatives and policies. Using two illustrative case studies, this paper explores opportunities for green work and the newer skills that might be required to enable sustainable agri-food systems. The case of Natural Farming Fellows (NFFs), a unique programme to encourage young agri-graduates to pursue Natural Farming is presented to understand enabling processes at the grassroots level. The second study explores institutional initiatives to engage rural youth through discussing the pedagogy and curricular approach of a Gandhian university along with opportunities to intern with field organisations. Together, these cases illustrate possible pathways and complexities underlying the process of nurturing sustainable livelihoods, the conception of which needs a broader idea of skilling based on personal aspirations and institutional support.

Evolution of fungal and non-fungal eukaryotic communities in response to thermophilic co-composting of various nitrogen-rich green feedstocks.

Thermophilic composting is a promising soil and waste management approach involving diverse micro and macro-organisms, including eukaryotes. Due to sub-optimal amounts of nutrients in manure, supplemental feedstock materials such as Lantana camara, and Tithonia diversifolia twigs are used in composting. These materials have, however, been reported to have antimicrobial activity in in-vitro experiments. Furthermore, the phytochemical analysis has shown differences in their complexities, thus possibly requiring various periods to break down. Therefore, it is necessary to understand these materials' influence on the biological and physical-chemical stability of compost. Most compost microbiome studies have been bacterial-centric, leaving out eukaryotes despite their critical role in the environment. Here, the influence of different green feedstock on the fungal and non-fungal eukaryotic community structure in a thermophilic compost environment was examined. Total community fungal and non-fungal eukaryotic DNA was recovered from triplicate compost samples of four experimental regimes. Sequencing for fungal ITS and non-fungal eukaryotes; 18S rDNA was done under the Illumina Miseq platform, and bioinformatics analysis was done using Divisive Amplicon Denoising Algorithm version 2 workflow in R version 4.1. Samples of mixed compost and composting day 84 recorded significantly (P<0.05) higher overall fungal populations, while Lantana-based compost and composting day 84 revealed the highest fungal community diversity. Non-fungal eukaryotic richness was significantly (P< 0.05) more abundant in Tithonia-based compost and composting day 21. The most diverse non-fungal eukaryotic biome was in the Tithonia-based compost and composting day 84. Sordariomycetes and Holozoa were the most contributors to the fungal and non-fungal community interactions in the compost environment, respectively. The findings of this study unravel the inherent influence of diverse composting materials and days on the eukaryotic community structure and compost's biological and chemical stability.

The unexpected occurrence of enigmatic ‘percevalicrinids’ (Echinodermata, Crinoidea) in the Lower Jurassic strata of North Africa — Implications for their stratigraphic and palaeogeographic distribution and discussion on their belonging to the subfamily Balanocrininae

The marl and limestone alternations of the Lower Jurassic Ain Ouarka and Ain Rhezala formations (Pliensbachian–Toarcian) in the western Saharan Atlas, Northwest Algeria, yield a diverse micro- and macrofauna, including moderately numerous crinoids, which are represented by remains of isocrinids, i.e., Balanocrinus ticinensis Hess and columnals of the genus Percevalicrinus. So far, the latter genus has been observed from the Upper Jurassic–Lower Cretaceous strata of Eurasia, North America, and the African continent. Thus, the present find is the oldest record of this crinoid genus, and the second one from the southern Tethyan margin. In this paper, it is shown that Percevalicrinus, which is traditionally regarded as a representative of the subfamily Balanocrininae, displays several features of the subfamily Isocrininae. The crinoid assemblage and associated facies and invertebrate fauna are typical of a low-energy deep outer shelf/ramp (below the storm wave-base) setting.

Electrically Controlled Click‐Chemistry for Assembly of Bioactive Hydrogels on Diverse Micro‐ and Flexible Electrodes

Inside Cover: In article 2200557, Ivan Rusev Minev and co-workers use electrochemical method to assemble semi-synthetic hydrogels directly on electronically conductive surfaces by using an electrochemical-chemicalchemical (ECC) mechanism. Hydrogels consisting of poly (ethylene glycol) (PEG) and heparin building blocks (functional biomolecule) are crosslinked by spatially controlling the click reaction between their thiol and maleimide moieties using electro-assisted 3D printing method. The gels are grown as coatings or 2D patterns on ITO, gold, and PtIr microelectrode.

Electrically Controlled Click-Chemistry for Assembly of Bioactive Hydrogels on Diverse Micro- and Flexible Electrodes.

The seamless integration of electronics with living matter requires advanced materials with programmable biological and engineering properties. Here electrochemical methods to assemble semi-synthetic hydrogels directly on electronically conductive surfaces are explored. Hydrogels consisting of poly (ethylene glycol) (PEG) and heparin building blocks are polymerized by spatially controlling the click reaction between their thiol and maleimide moieties. The gels are grown as conformal coatings or 2D patterns on ITO, gold, and PtIr. This study demonstrates that such coatings significantly influence the electrochemical properties of the metal-electrolyte interface, likely due to space charge effects in the gels. Further a promising route toward engineering and electrically addressable extracellular matrices by printing arrays of gels with binary cell adhesiveness on flexible conductive surfaces is highlighted.

Towards the development of new generation spin-orbit photonic techniques

Spin–orbit interaction deals with the interaction and coupling of spin and orbital angular momentum degrees of freedom of spinning particles, which manifests in diverse fields of physics, ranging from atomic, condensed matter to optical systems. In classical light beams, this has led to a number of non-trivial optical phenomena like spin and orbital Hall effect of light, optical Rashba effect, photonic Aharonov–Bohm effect, rotational Doppler effect, transverse spin, Belinfante’s spin-momentum and spin-momentum locking etc. These have been observed in diverse micro- and nano-scale optical systems. These have generated a new area in photonics, namely, spin-orbit photonics that not only deals with fundamental light–matter interaction effects but also opened up the feasibility of a new generation of miniaturized and on-chip integrable multifunctional photonic devices based on the angular momentum and geometrical phase of light. This paper will introduce the emerging field of spin-orbit photonics and will cover the representative spin-orbit photonic effects in a variety of light-matter interactions with examples. In this regard, we also present proof-of-concept demonstrations of two interesting techniques based on the geometrical phase of light, namely, geometrical phase polarimeter and weak value polarimeter.

Morphologically Diverse Micro- and Macrostructures Created via Solvent Evaporation-Induced Assembly of Fluorescent Spherical Particles in the Presence of Polyethylene Glycol Derivatives.

The creation of fluorescent micro- and macrostructures with the desired morphologies and sizes is of considerable importance due to their intrinsic functions and performance. However, it is still challenging to modulate the morphology of fluorescent organic materials and to obtain insight into the factors governing the morphological evolution. We present a facile bottom-up approach to constructing diverse micro- and macrostructures by connecting fluorescent spherical particles (SPs), which are generated via the spherical assembly of photoisomerizable azobenzene-based propeller-shaped chromophores, only with the help of commercially available polyethylene glycol (PEG) derivatives. Without any extra additives, solvent evaporation created a slow morphological evolution of the SPs from short linear chains (with a length of a few micrometers) to larger, interconnected networks and sheet structures (ranging from tens to >100 µm) at the air–liquid interface. Their morphologies and sizes were significantly dependent on the fraction and length of the PEG. Our experimental results suggest that noncovalent interactions (such as hydrophobic forces and hydrogen bonding) between the amphiphilic PEG chains and the relatively hydrophobic SPs were weak in aqueous solutions, but play a crucial role in creating the morphologically diverse micro- and macrostructures. Moreover, short-term irradiation with visible light caused fast morphological crumpling and fluorescence switching of the obtained structures.

Bioerosion and fungal colonization of the invasive foraminiferan &amp;lt;i&amp;gt;Amphistegina lobifera&amp;lt;/i&amp;gt; in a Mediterranean seagrass meadow

Abstract. Foraminiferans are diverse micro- to macroscopic protists abundant especially in (sub)tropical seas, often forming characteristic benthic communities known as “living sands”. Numerous species have migrated through the Suez Canal to the Mediterranean and one of them, i.e., Amphistegina lobifera, turned invasive, gradually outcompeting the indigenous species. At some places, A. lobifera creates thick seabed sediments, thus becoming an important environmental engineer. However, little is known about the turnover of its shells in the invaded ecosystems. Using vital staining, stereomicroscopy, scanning electron microscopy, and cultivation and DNA fingerprinting, I investigated the vital status, destruction/decomposition and mycobiota of A. lobifera in the rhizosphere of the dominant Mediterranean seagrass Posidonia oceanica in an underwater Maltese meadow (average 284 shells g−1, representing 28.5 % of dry substrate weight), in comparison with epiphytic specimens and P. oceanica roots. While 78 % of the epiphytes were alive, nearly all substrate specimens were dead. On average, 80 % of the epiphytes were intact compared to 21 % of the substrate specimens. Abiotic dissolution and mechanical damage played only a minor role, but some bioerosion was detected in 18 % and &gt;70 % of the epiphytic and substrate specimens, respectively. Few bioerosion traces could be attributed to fungi, and the majority probably belonged to photoautotrophs. The seagrass roots displayed fungal colonization typical for this species and yielded 81 identified isolates, while the surface-sterilized substrate specimens surprisingly yielded no cultivable fungi compared to 16 other identified isolates obtained from the epiphytes. While the epiphytes' mycobiota was dominated by ascomycetous generalists also known from terrestrial ecosystems (alongside with, for example, a relative of the “rock-eating” extremophiles), the roots were dominated by the seagrass-specific dark septate endophyte Posidoniomyces atricolor and additionally contained a previously unreported lulworthioid mycobiont. In conclusion, at the investigated locality, dead A. lobifera shells seem to be regularly bioeroded by endolithic non-fungal organisms, which may counterbalance their accumulation in the seabed substrate.

A Desaturase-Like Enzyme Catalyzes Oxazole Formation in Pseudomonas Indolyloxazole Alkaloids.

Indolyloxazole alkaloids occur in diverse micro- and macroorganisms and exhibit a wide range of pharmacological activities. Despite their ubiquitous occurrence and simple structures, the biosynthetic pathway remained unknown. Here, we used transposon mutagenesis in the labradorin producer Pseudomonas entomophila to identify a cryptic biosynthetic locus encoding an N-acyltransferase and a non-heme diiron desaturase-like enzyme. Heterologous expression in E. coli demonstrates that both enzymes are sufficient to produce indolyloxazoles. Probing their function in stable-isotope feeding experiments, we provide evidence for an unusual desaturase mechanism that generates the oxazole by decarboxylative cyclization.

A Desaturase‐Like Enzyme Catalyzes Oxazole Formation in Pseudomonas Indolyloxazole Alkaloids

AbstractIndolyloxazole alkaloids occur in diverse micro‐ and macroorganisms and exhibit a wide range of pharmacological activities. Despite their ubiquitous occurrence and simple structures, the biosynthetic pathway remained unknown. Here, we used transposon mutagenesis in the labradorin producer Pseudomonas entomophila to identify a cryptic biosynthetic locus encoding an N‐acyltransferase and a non‐heme diiron desaturase‐like enzyme. Heterologous expression in E. coli demonstrates that both enzymes are sufficient to produce indolyloxazoles. Probing their function in stable‐isotope feeding experiments, we provide evidence for an unusual desaturase mechanism that generates the oxazole by decarboxylative cyclization.

ROLE OF MICROFINANCE INSTITUTIONS IN FINANCING MICRO AND SMALL ENTERPRISES IN ETHIOPIA

Micro and Small Enterprises (MSEs) understood as a means to attain the United Nations 2030 agenda particularly its contribution in reducing the massive unemployment and deep-rooted poverty. Hence, the main aim of this paper is to examine the role of Microfinance Institutions (MFIs) to the survival, value creation and growth of MSEs. For this study purpose, secondary data were collected from the National Bank of Ethiopia (NBE) and triangulated with systematic review of empirical evidences. Principal Component Analysis (PCA) was used to examine the relationships and significance in and between the data emerge. The empirical evidences result reveals that unlike banks, MFIs provide diverse micro credit services to address the diverse socio-economic needs of the poor who cannot afford collateral requirement and besides the result from PCA reveals that the economic growth and access to microcredit service by itself is not enough to create more jobs as they are uncorrelated. However, the empirical evidences shows that, the poorest and most vulnerable people are being left behind due to lack of access to finance, poor market linkage and inadequate skill training among many other factors. Therefore, policy-makers have to develop regulatory frameworks that build sound financial institutions and encourage competition among one another.

Effects of Two-Step Anodization on Surface Wettability in Surface Treatment of Aluminum Alloy

Industrial anodizing of aluminum alloys is widely employed for various products, to improve corrosion and contamination protection as well as aesthetic appearance. At the same time, nanostructure fabrication using highly ordered porous aluminum oxides has been increasingly investigated in academic research for diverse micro-/nano applications. This approach is based on two-step anodization with limited process conditions, such as extended process time and low temperature. In this study, two-step anodizing was employed to anodize hairline-finished Al 1050 with sulfuric acid considering industrial processing conditions. The method is particularly suited for anodized products that require post-processing such as printing, dyeing and/or bonding. Porous anodized layers that were fabricated using conventional single anodizing, and twostep anodizing under identical processing conditions were compared. Variations in porosity, pore diameter, and inter-pore distance were examined in relation to the anodizing parameters, such as temperature and voltage. The results showed that two-step anodizing caused an increase in all measured pore-related measurements, and produced a much more uniform porous layer than the conventional anodizing process. Water contact angles were evaluated on the anodized surface of the previously machined hairline specimen. It was found that the water contact angles clearly decreased on the surfaces treated by two-step anodization, compared to the conventional anodizing process.

Settling and rising velocities of environmentally weathered micro- and macroplastic particles

Microplastic is exposed to numerous weathering processes in the environment, which change particle properties and thus influence transport behaviors, including settling and rising velocities in aquatic environments. However, the extent to which particles in the environment differ from virgin particles in their transport behaviors has not yet been investigated. The settling and rising velocities of weathered fluvial microplastic and macroplastic particles collected from environmental samples are determined in this study and the transferability of theoretical approaches to predicting their transport behaviors is examined. The settling velocities of the environmental particles were between 0.16 and 3.52 cm/s and the rising velocities between 0.18 and 19.85 cm/s. Formulas were applied that were developed using experiments with virgin microplastic, but do not account for the effects of environmental impacts such as degradation, fragmentation and biofouling on the velocities. Accordingly, the transferability of the formulas to environmental particles must be verified. The formulas proved to be suitable for describing the settling and rising velocities of environmental microplastic particles in the shapes of pellets, fragments and foams, and were less suitable for describing the velocities of films and macroplastic particles. Further experiments will be necessary in the future to integrate effects from biofilm and particle deformation on the transport behaviors to adequately model the behavior of the highly diverse micro- and macroplastic particles in the aquatic environment.

Advanced Materials Prepared via Metallic Reduction Reactions for Electrochemical Energy Storage

AbstractAdvanced materials with various micro‐/nanostructures have attracted plenty of attention in energy storage field over the past decades. Metallic reduction reactions (MRRs) possess the merits of low energy consumption, flexibility, convenience, and scalability, which have been considered as potential methods to acquire diverse micro‐/nanostructured materials. In this review, the latest progress of MRRs is systematically summed up, featuring the usage of metallic reductants (e.g., magnesium, aluminum, zinc, lithium) on synthesizing of advanced micro‐/nanostructured materials and their applications in various energy storage systems. The as‐obtained materials (e.g., carbon‐, silicon‐, germanium‐, antimony‐, and titanium‐based materials) can deliver various architectures, including solid spherical structures, hollow porous structures, core–shell structures, yolk–shell structures, core–satellite structures, and many kinds of 1D, 2D, 3D micro‐/nanostructures. Besides, the defect properties of materials can be well tuned via MRRs. The application progress of these materials as active electrodes, host materials, or functional interlayers for lithium ion batteries, lithium sulfur batteries, sodium ion batteries, or supercapacitors is reviewed. In the end, the strengths and insufficiencies of MRRs are discussed and the probable future research directions of MRRs are proposed.

Communication and Household Adoption of Heating Products in Hungary

Existing studies of heating products have analyzed the adoption of energy-efficient heating technologies from diverse micro and macroeconomic aspects, such as diffusion of innovation, willingness to pay, business models, energy pricing, etc., but the analysis from a marketing management approach based on end customer insight is still lacking. Understanding the decision-making process of end customers, and the influence of social environment at the diverse stages of the purchase process leads to a focused market strategy, thereby contributes toward overcoming the multi-level segmentation challenge faced by the manufacturers of heating products. In this context, a two-step exploratory research was conducted in December 2013 with end customers of the residential heat market in Hungary. The end customers were found to be active decision-makers engaged in deliberate planning in the purchase of heating products. They start searching for information by turning mainly to online information sources and they actively integrate their social network in all stages of the decision-making process, which means that the role of the installer is relatively less influential along the whole purchasing process. Identified influencing communication channels at the diverse stages of the purchase process may support manufacturers to develop a user-centric marketing strategy by optimizing the communication instruments in their marketing mix by, for instance, including direct end customer communication via online channels and by de-emphasizing offline communication channels.

Probabilistic modelling of printed dots at the microscopic scale

Microscopic analysis of paper printing shows regularly spaced dots whose random shape depends on the printing technology, the configuration of the printer as well as the paper properties. The modelling and identification of paper and ink interactions are required for qualifying the printing quality, for controlling the printing process and for application in authentication as well. This paper proposes an approach to identify the authentic printer source using micro-tags consisting of microscopic printed dots embedded in the documents. These random shape features are modelled and extracted as a signature for a particular printer. In the paper, we propose a probabilistic model consisting of vector parameters using a spatial interaction binary model with inhomogeneous Markov chain. These parameters determine the location and describe the diverse micro random structures of microscopic printed dots. A Markov chain Monte Carlo (MCMC) algorithm is thus developed to approximate the Minimum Mean Squared Error estimator. The performance is assessed through numerical simulations. The real printed dots from the common printing technologies (conventional offset, waterless offset, inkjet, laser) are used to assess the effectiveness of the model.