Scaling Analysis Research Articles

Capillary Orientation and Morphology Dictated Oscillatory Electro-magneto-imbibition of Viscoelastic Electrolytes.

We explore the intricate dynamics of imbibition by a viscoelastic electrolyte within an arbitrarily oriented, nonuniform microcapillary, while under the stimulus of external electromagnetic fields and internal electroviscous forces stemming from streaming potential. The microcapillary walls are envisaged to be tapered relative to each other, with the entire system inclined with respect to the horizontal plane. The rheological behavior of the electrolyte is characterized using the Phan-Thien-Tanner (PTT) model. To manipulate the imbibition dynamics, external transverse magnetic and electric fields are imposed. Incorporating all contributing forces, we obtain semianalytical formulations for the velocity and shear stress distributions. We identify distinct stages during the imbibition process: (i) initial, (ii) filling, (iii) oscillatory, and (iv) stagnation stages. Moreover, we scrutinize the impact of four pivotal parameters, namely, the Weissenberg number (Wi), the Hartmann number (Ha), the transverse electric to viscous force (EVF) number (S), and the electric Reynolds number (Ree), on the imbibition dynamics across different inclinations and taper angles. We also delineate the parameter space for these four parameters, identifying where the onset of oscillations occurs. Finally, through scaling analysis, we establish the existence of four distinct regimes corresponding to the aforementioned stages: (i) the linear regime, (ii) the Washburn regime, (iii) the oscillatory regime, and (iv) the equilibrium regime. Our findings are anticipated to enhance the understanding of capillary imbibition under such complex flow conditions and contribute significantly to the advancement of capillarity-driven microfluidic devices.

Analysis of Scale of Business in mediating Financial Technology and Knowledge Management on Digital-Based Accounting of Micro, Small and Medium Enterprises in Medan City

Micro, small and medium enterprises are businesses that can help neraga in improving the community's economy, reducing unemployment so that the government is now very enthusiastic in supporting the development of MSMEs. It is inseparable from the local government of Medan City which motivates business actors in using digitalisation in every sector in running a business so that it can develop not only at the national level but even at the international level. This research was conducted in Medan City with the variables used were Scale of Business, Finalcial Technology with Knowledge Management as the mediating variable on digital-based accounting of MSMEs. The population in this study were MSMEs under the guidance of the Medan City UKM cooperative office which already had a Business Identification Number of 488 businesses with a sampling method using the Slovin formula with an error rate of 5%. The analysis model used to test the hypothesis in this study is multiple regression analysis using the Smart PLS application. multiple regression analysis is a statistical method used to determine the magnitude of the influence between independent variables. Indirectly Scale of Business Mediates Financial Technology, on Digital-Based Accounting, Indirectly Scale of Business does not Mediate Knowledge Management, on Digital-Based Accounting, Directly Scale of Business, Financial Technology, Knowledge Management, have a significant effect on Digital-Based Accounting, Directly, Financial Technology has a significant effect on Scale of Business, Directly, Knowledge Management does not have a significant effect on Scale of Business micro small and medium enterprises in Medan City.

Dorsal fin height is not an effective tool to distinguish hatchery and wild steelhead in the field

AbstractObjectiveTo maximize harvest of hatchery steelhead Oncorhynchus mykiss and Pacific salmon Oncorhynchus spp. while reducing impacts to wild conspecifics, fishery managers rely on the ability of anglers to distinguish between the two. Fin erosion, including dorsal fin erosion, is a common result of hatchery rearing of juvenile salmonids. Since the 1980s, managers in the Pacific Northwest have utilized adult steelhead dorsal fin height as a regulatory control rule, requiring anglers to release steelhead with dorsal fins over a height threshold. This approach assumes that all or most hatchery fish have shorter dorsal fins than their wild counterparts. This study was designed to test this assumption.MethodsWe compared steelhead origin (hatchery or wild) determined using scale analysis and adipose fin clipping (hatchery n = 127, wild n = 71) with origin estimated using dorsal fin height.ResultOverall, a static dorsal fin height threshold (2.25 in, 5.72 cm) correctly identified 90% of hatchery‐origin steelhead but misidentified nearly half (44%) of wild fish as hatchery. Dorsal fin height of known hatchery fish correlated with fish length, indicating a weakness of using a static dorsal height threshold as a management tool. The accuracy of distinguishing wild fish improved, but only marginally (56–76%), using a classification model where dorsal fin height of known origin fish from this study was a continuous predictor of origin. In comparison, adipose fin status correctly identified 97% of unmarked fish as wild.ConclusionThe low accuracy of the classification model and static dorsal fin height thresholds at distinguishing hatchery and wild steelhead due to a strong correlation between dorsal fin height and fork length and the high fork length variability of hatchery origin fish. Given the low cost and accuracy of adipose fin clipping and the potentially high conservation risk associated with misidentification, we recommend discontinuing the use of dorsal fin height as a harvest control rule for steelhead.

Factor structure and validation of the electronic form of the Oxford Happiness Questionnaire in patients with COVID-19

Background and Objectives: Background and Aim: Validity Scale Validation can help identify coronavirus disease patients; therefore, the aim of this study was to evaluate the validation of the electronic form of the Oxford Happiness Questionnaire in patients with COVID-19. Methods: This study is instrumental psychometrics that the statistical population includes all patients in 19 cases in Tehran. The number of samples was determined based on psychometric criteria to be 100 for the predictive validity section and 251 for the convergence validity section. Samples were selected by cluster sampling. Research data were collected electronically through two questionnaires of happiness (Oxford) and happiness of positive psychological characteristics by sending the questionnaire link to the participants' mobile phones. To evaluate the validity of the scale, content validity, convergence, and factor analysis methods were used. The reliability of the scale was assessed by internal consistency methods and class reliability. Results: The results of exploratory factor analysis showed that the researcher-made questionnaire consists of three factors and has good validity and reliability. The second-order confirmatory factor analysis also confirmed the three-factor model. This questionnaire was administered along with the short form of the Oxford Happiness Scale, which had 13 items of good reliability and validity. Conclusion: The Oxford Happiness Scale in COVID-19 patients can be used to assess happiness in COVID-19 patients.

Psychological predictors of incident subjective cognitive complaints in community dwelling older adults

Background Subjective cognitive complaint (SCC) is associated with future cognitive decline and may be a marker for clinical intervention in the progression to dementia. Among the viable predictors of SCC, psychological factors are clinically relevant, non-invasive early indicators of older adults at elevated risk. This aim of this study is to determine whether psychological symptoms: dysphoria and apathy precede incident SCC in the dementia pathway. Methods Participants (n = 592) enrolled in the Central Control of Mobility in Aging Study were includes in the analyses, with prevalent cases excluded. Apathy and dysphoria scale scores were derived using confirmatory factor analysis of the Geriatric Depressive Scale. Cox regression analyses was used to determine the association between apathy and dysphoria scores and incident SCC. Results Over a mean follow up of 1.90 years, 44 individuals (9.26%) developed incident SCC. Baseline apathy scale score was significantly associated with 4-fold increased risk of SCC (HR 4.39, 95%CI: 1.32–14.67), adjusted for cognition but not age and dysphoria scale score. Baseline dysphoria scale score was not associated with increased risk of SCC in adjusted analyses. Conclusion In this longitudinal analysis of community dwelling older adults, apathy was associated with an increased risk of SCC, when adjusting for cognition but not dysphoria. Finally, this study highlights apathy as an early risk factor, which may precede SCC in the progression to dementia and consequently, may identify a high risk group for clinical screening and intervention.

The Occurrence of Myxomycete Communities in Taxodium distichum Forests: Influence of Substrates and Seasons

Myxomycete communities in Taxodium distichum forests and the influence of substrates and seasons on myxomycete diversity were studied. In total, 80 substrates (40 living barks and 40 litters) were collected from the sample site in winter, spring, summer and autumn of 2023, followed by moist chamber cultures. A total of 733 records representing 34 myxomycete species in 21 genera were obtained. Arcyria cinerea and six other species were abundant (A). Six species were common (C), six species were occasional (O), and fifteen species were rare (R). Species diversity (H’ = 2.04 ± 0.20) of corticolous communities was significantly higher than that (H’ = 1.49 ± 0.31) of litter-inhabiting communities (p < 0.05). Nonmetric Multidimensional Scaling (NMDS) analyses showed significant differences between these two communities (p < 0.01). Species diversity was slightly higher in summer and autumn compared to winter and spring. NMDS analyses indicated no significant differences among seasonal communities. Redundancy Analysis showed that the corticolous species were closely related to wind speed (p < 0.05), while litter-inhabiting species were mainly determined by temperature (p < 0.05). The study revealed that substrates and seasons influenced myxomycete communities in T. distichum forests, with the communities being particularly affected by the substrates in which they live.

Integrated Scheduling of Handling Equipment in Automated Container Terminal Considering Quay Crane Faults

Quay cranes (QCs) play a vital role in automated container terminals (ACTs), and once a QC malfunctions, it will seriously affect the operation efficiency of ships being loaded and unloaded by the QC. In this study, we investigate an integrated scheduling problem of quay cranes (QCs), yard cranes (YCs), and automated guided vehicles (AGVs) under QC faults, which is aimed at minimizing the loading and unloading time by determining the range of adjacent operational QCs of the faulty QCs and reallocating unfinished container handling tasks of QCs. A mixed integer programming model is formulated to dispatch QCs, YCs, and AGVs in ACTs. To solve the model, an adaptive two-stage NSGA-II algorithm is proposed. Numerical experiments show that the proposed algorithm can significantly reduce the impact of faulty QCs on productivity while maintaining its synchronous loading and unloading efficiency. The sensitivity analysis of ship scale, location, and number of faulty QCs indicates that the number of faulty QCs has a greater influence on the loading and unloading efficiency than their locations, and the impact of faulty QCs on the efficiency of small-scale ships is greater than that of large-scale ships.

Nanozyme Hydrogels Promote Nerve Regeneration in Spinal Cord Injury by Reducing Oxidative Stress.

Inhibiting secondary cell death and promoting neuronal regeneration are critical for nerve repair after spinal cord injury (SCI). The excessive accumulation of reactive oxygen species (ROS) after SCI causes cell death and induces apoptosis. These reactions further increase the level of ROS production, leading to a vicious cycle of spinal cord tissue damage. Therefore, intervention targeting ROS is a potential therapeutic approach to improve the recovery of locomotor function after SCI. In this study, we designed and synthesized a nanozyme hydrogel delivery system loaded with multiple drugs, LA/Me/Se NPs-h. LA/Me/Se NPs-h exhibited a satisfactory size distribution and excellent stability, enhancing the bioavailability of therapeutic drugs. Moreover, we explored the antioxidant and protective effects of LA/Me/Se NPs-h against oxidative stress-induced cell damage caused by ROS production after SCI in vitro. In the mice SCI model, the Basso mouse scale and gait analysis showed that LA/Me/Se NPs-h significantly promoted the recovery of locomotor function after SCI. The histological and immunofluorescence results of the injury site revealed that LA/Me/Se NPs-h upregulated the expression of GFAP, NF-200, and superoxide dismutase in spinal cord lesion, reduced caspase-3 expression, improved spinal cord continuity, reduced lesion cavity, and inhibited the axonal demyelination. Consequently, LA/Me/Se NPs-h increased the activity of antioxidant enzymes and reduced neuronal apoptosis by reducing oxidative stress and ultimately promoted nerve regeneration. Taken together, this study demonstrated promising nanozyme hydrogels and provided an effective therapeutic strategy for SCI and other ROS-related diseases.

Summer evapotranspiration-cloud feedbacks in land-atmosphere interactions over Europe

AbstractLand-atmosphere (L-A) feedbacks are important for understanding regional climate functioning. However, the accurate quantification of feedback strength is challenging due to complex, nonlinear interactions and varying background atmospheric conditions. In particular, the role of cloud water in the terrestrial water cycle is often ignored or simplified in previous L-A feedback studies, which overlook the relationship between evapotranspiration (ET) and cloud water (TQC). This study diagnoses the interactions between $$\:ET$$, $$\:TQC$$ and its dynamics ($$\:\varDelta\:TQC/\varDelta\:t$$) under different atmospheric conditions by conducting correlation and a novel scaling analysis, based on a coupled regional climate model simulation. Contrasting correlation relationships between $$\:ET$$, $$\:TQC$$ and $$\:\varDelta\:TQC/\varDelta\:t$$ were identified, indicating the positive feedback between $$\:ET$$ and the dynamics in cloud water. Two types of positive scaling relationships between $$\:ET$$ and $$\:\varDelta\:TQC/\varDelta\:t$$ were identified by K-means clustering. The analysis shows a contrasting north-south distribution of the scaling relationship that is similar to the spatial distribution of energy-limited and water-limited $$\:ET$$ regimes, highlighting the role of ET regimes in modulating the $$\:ET$$ - $$\:\varDelta\:TQC/\varDelta\:t$$ scaling relationships. Moreover, the feedback strength and scaling relationship are affected by atmospheric moisture flux dynamics, providing remote moisture sources and altering dry/wet conditions. Our results highlight the role of cloud water in the atmospheric part of the L-A process chain and reveal the effect of different atmospheric conditions on L-A interactions based on the new analysis framework.

Studies of genetic diversity and genome-wide association for vitamin C content in lettuce (Lactuca sativa L.) using high-throughput SNP arrays.

Lettuce (Lactuca sativa L.) is a source of beneficial compounds though they are generally present in low quantities. We used 40K Axiom and 9K Infinium SNP (single nucleotide polymorphism) arrays to (i) explore the genetic variability in 21 varieties and (ii) carry out genome-wide association studies (GWAS) of vitamin C content in21 varieties and a population of 205 plants from the richest variety in vitamin C ('Lechuga del Pirineo'). Structure and phylogenetic analyses showed that the group formed mainly by traditional varieties was the most diverse, whereas the red commercial varieties clustered together and very distinguishably apart from the rest. GWAS consistently detected, in a region of chromosome 2, several SNPs related to dehydroascorbic acid (a form of vitamin C) content using three different methods to assess population structure, subpopulation membership coefficients, multidimensional scaling, and principal component analysis. The latter detected the highest number of SNPs (17) and the most significantly associated, 12 of them showing a high linkage disequilibrium with the lead SNP. Among the 84 genes in the region, some have been reported to be related to vitamin C content or antioxidant status in other crops either directly, like those encoding long non-coding RNA, several F-box proteins, and a pectinesterase/pectinesterase inhibitor, or indirectly, like extensin-1-like protein and endoglucanase 2 genes. The involvement of other genes identified within the region in vitamin C levels needs to be further studied. Understanding the genetic control of such an important quality trait in lettuce becomes very relevant from a breeding perspective.

A hovering bubble with a spontaneous horizontal oscillation

Active matters, characterized by multi-mode motions, have been emerging for both engineering and biological applications. Generally, active objects rely on the symmetry-broken structures, compositions, or interfacial activities through a physical or chemical approach. Here, we report an active bubble spontaneously hovering with a horizontal oscillation at the solid/liquid interface by impacting a stationary laser beam into a liquid through a transparent solid cover. This spontaneous oscillation mode of the bubble synchronizes with that of the interfacial temperature and hydrodynamical flow. A physical mechanism is proposed, and the scaling analysis of the oscillation frequency agrees well with experiments in various liquids under different laser powers. Additionally, the bubble trajectory rotates azimuthally, arising from the symmetry breaking of the vortex pair accompanying the oscillation. Moreover, the double pendulum of oscillation bubbles has been demonstrated, achieving a preferable oscillation direction in a controllable way. These findings would not only advance our understanding of active matters but also shed light on the bubble-mediated technological applications, such as microrobots and drug deliveries.

Multidimensional analysis of textiles coated with electroactive polymers for actuators

This paper presents a multidimensional analysis of textiles coated with conductive polymers for actuators. The purpose of using multidimensional scaling analysis is to compare similarities and dissimilarities between conductive textiles obtained through conductive polymeric film deposition to observe the optimal value for electrical resistance and to select an adequate method to achieve conductive fabric using different polymers (polyethylene glycol, polyvinyl alcohol or polyvinylidene fluoride) and metal microparticles (copper or nickel). The multidimensional analysis is based on mapping a series of material properties from a proximity matrix (similarities or dissimilarities) between these properties. Multidimensional scaling allows rebuilding the exact map of the values (within approximately a symmetry or rotation). To fit dissimilarity or similarity matrices for multiple variables into one common space estimating the weight parameters for each variable, the INDSCAL model (individual differences multidimensional scaling) was used.

Flowerlike Spreading of Micellar Films during Emulsion Drop Evaporation

We investigated the film spreading during the evaporation of submillimeter oil-in-water emulsion droplets on a solid surface, and observed a novel phenomenon where the film follows a two-layer spreading. In combination with the instability at the film front, the spreading front acquires a flowerlike pattern. The emergence of the two-layer structure is attributed to micelles within the oil film that yield an oscillating disjoining pressure. By considering both the slipping condition and the disjoining pressure, a scaling analysis is carried out that agrees well with the observed film spreading dynamics. The film spreading follows Tanner’s law initially, while it becomes faster at a later stage, where the film radius follows r∼t1/2 for weak slip and r∼t3/8 for strong slip conditions. Published by the American Physical Society 2024

Rasch analysis of the new general self efficacy scale: an evaluation of its psychometric properties in older adults with low vision

BackgroundWhile general self-efficacy is known to relate to achievement in many areas, it has rarely been evaluated in individuals with low vision. Here we explore the psychometric properties and targeting of the New General Self Efficacy Scale (NGSES) using Rasch analysis in data collected from older adult clinical trial participants with low vision.MethodsParticipants (n = 121) completed pre-intervention telephone questionnaires (i.e., NGSES, Activity Inventory (AI), Beck Depression Inventory (BDI), SF-36, and the Telephone Interview for Cognitive Status (TICS). Rasch analysis using the Method of Successive Dichotomizations (MSD) was applied to NGSES, AI, and BDI datasets to estimate person and item measures, and ordered rating category thresholds.NGSES infit mean square statistics and standard errors were analyzed to test whether data fit Rasch model requirements, and targeting was assessed by comparing distributions of person and item measures. Multiple linear regression evaluated the influence of participant characteristics on NGSES person measures.ResultsThere was a significant difference (p = 0.01) in the distributions of NGSES person measures (mean = 0.85, range -2.1-3.2) and item measures (mean = 0, range -1.0-0.72). Infit mean square statistics and standard errors for item and person measures conformed to expectations of the Rasch model.Greater NGSES person measure was related to lower BDI person measure (β = -0.48, p < 0.0005, 95% CI -0.67—-0.28) and higher AI person measure (β = 0.11, p = 0.047, 95% CI 0.0013 – 0.22) after controlling for cognitive status (TICS). Other variables including SF-36, visual acuity, and patient demographics were not related to NGSES person measure.ConclusionsWhile NGSES person measures estimated from a low vision patient population conformed to basic Rasch model requirements, the significant differences in the person and item measure distributions indicate poor NGSES targeting, specifically a ceiling effect. Therefore, there is limited discrimination between persons at the upper end of the scale. While further work can evaluate how self-efficacy may be associated with other factors in the low vision patient population, the ceiling effect found in this study cautions interpretation of NGSES results for those with high general self-efficacy.Trial registrationPre-registered on clinicaltrials.gov, identifier NCT04926974.

Revisiting a Drag Partition Model For Canopy-Like Roughness Elements

Turbulent flows over a large surface area (S) covered by n obstacles experience an overall drag due to the presence of the ground and the protruding obstacles into the flow. The drag partition between the roughness obstacles and the ground is analyzed using an analytical model proposed by Raupach (Boundary-Layer Meteorol 60:375-395, 1992) and is hereafter referred to as R92. The R92 is based on the premise that the wake behind an isolated roughness element can be described by a shelter area A and a shelter volume V. The individual sizes of A and V without any interference from other obstacles can be determined from scaling analysis for the spread of wakes. To upscale from an individual roughness element to n/S elements where wakes may interact, R92 adopted a background stress re-normalizing instead of reducing A or V with each element addition. This work demonstrates that R92’s approach results in a linear background stress reduction in A and V only when the ratio of n/S is small, due to a low probability of wake interactions. This probabilistic nature suggests that up-scaling from individual to multiple roughness elements can be re-formulated using stochastic averaging methods proposed here. The two approaches are shown to recover R92 under plausible conditions. An alternative scaling for the shelter volume is also proposed here using thermodynamic arguments of work and dissipation though the final outcome remains similar to R92. Comparisons between R92 and available data spanning more than two decades after R92 on blocks and vegetation-like roughness elements confirm the practical utility of R92. The agreement between R92 and this updated databases of experiments and simulations confirm the potential use of R92 in large-scale models provided that the relevant parameters accommodate certain features of the roughness element type (cube versus vegetation-like) and, to a lesser extent, their configuration throughout S. Last, a comparison between R92 and models based on first-order closure principles with constant mixing length suggests that R92 can outperform such models when evaluated across a wide range of roughness densities.

Evaluación de las relaciones humanas con otras especies animales

Few worksexplore the assessments that laypeople make about practices that involve animals. This study tests the multiple sorting tasks (MST) as a method to explore perceptions of animals. 115people of different genders, and age groups, and the condition of owning a pet or not, assessedpractices that make use of animals. Theinquiry was made throughan interview based on a conceptualisation ofthe freesortingsof18 cardswith text and18 images that contain practices involving animals, and whether the conditionof having a pet or notinfluenced their conceptualisations. A multidimensional scaling analysis(MSA), indicates that people classify the practices based on the function animals have for society, however are worriedaboutthe conditions in which animals are used. The results discuss the importance that laypeople giveto the ethics of animal uses, and therole ofhaving apet or not,showing that young people are more sensitive to the welfare of animals.The results concludethat the participants conceptualise imagesdifferently according to whether they are asked to evaluate the practice representedonly by text; using images induces more moral conceptualisations than text. This demonstrates the utility of the MST and provides theoretical and practical implications for exploring people’sperceptions and educating them on animal welfare.

Analysis of lipid uptake, storage, and fatty acid oxidation by group 2 innate lymphoid cells

Group 2 Innate Lymphoid Cells (ILC2) are critical drivers of both innate and adaptive type 2 immune responses, known to orchestrate processes involved in tissue restoration and wound healing. In addition, ILC2 have been implicated in chronic inflammatory barrier disorders in type 2 immunopathologies such as allergic rhinitis and asthma. ILC2 in the context of allergen-driven airway inflammation have recently been shown to influence local and systemic metabolism, as well as being rich in lipid-storing organelles called lipid droplets. However, mechanisms of ILC2 lipid anabolism and catabolism remain largely unknown and the impact of these metabolic processes in regulating ILC2 phenotypes and effector functions has not been extensively characterized. ILC2 phenotypes and effector functions are shaped by their metabolic status, and determining the metabolic requirements of ILC2 is critical in understanding their role in type 2 immune responses and their associated pathophysiology. We detail here a novel experimental method of implementing flow cytometry for large scale analysis of fatty acid uptake, storage of neutral lipids, and fatty acid oxidation in primary murine ILC2 with complementary morphological analysis of lipid storage using confocal microscopy. By combining flow cytometry and confocal microscopy, we can identify the metabolic lipid requirements for ILC2 functions as well as characterize the phenotype of lipid storage in ILC2. Linking lipid metabolism pathways to ILC2 phenotypes and effector functions is critical for the assessment of novel pharmaceutical strategies to regulate ILC2 functions in type 2 immunopathologies.

Reading and Writing Research Based on Surname Group

This study examines the influence of surname on academic performance in higher education. It includes an in-depth analysis of comprehensive book circulation data from the library of Nanjing Normal University, covering the period from 2012 to 2023. The study uses Kendall coefficients to assess the consistency in book circulation and renewal among the top 300 surnames of readers, employs multidimensional scaling analysis to identify differences or similarities between categorical variables through direct distance assessment, uses chi-square tests to measure the correlation between surnames above and below the mean line and various categorical variables, and conducts survival analysis to examine circulation activities related to the top 300 surnames. Results are interpreted in the context of female-dominated education and teacher preparation. The results reveal a consistent pattern in the 12-year borrowing and renewal habits of the top 300 surnames of readers. A hierachical mismatch between the reader, book category, and author reflects complex reading interests beyond academic authority. In the wake of the COVID-19 pandemic, readers with surnames above the average have shown less interest in using the book renewal service. The borrowing and renewal activity for the disappeared surnames changed within two years for foreign language books and six years for Chinese books.

Ligand presentation controls collective MSC response to matrix stress relaxation in hybrid PEG-HA hydrogels

Cell interactions with the extracellular matrix (ECM) influence intracellular signaling pathways related to proliferation, differentiation, and secretion, amongst other functions. Herein, bone-marrow derived mesenchymal stromal cells (MSCs) are encapsulated in a hydrazone crosslinked hyaluronic acid (HA) hydrogel, and the extent of stress relaxation is controlled by systemic introduction of irreversible triazole crosslinks. MSCs form elongated multicellular structures within hydrogels containing RGD peptide and formulated with elastic composition slightly higher than the hydrogel percolation threshold (12 % triazole, 88 % hydrazone). A scaling analysis is presented (<RgStructure2>12 ∼Nα) to quantify cell-material interactions within these structures with the scaling exponent (α) describing either elongated (0.66) or globular (0.33) structures. Cellular interactions with the material were controlled through peptides to present integrin binding ECM cues (RGD) or cadherin binding cell-cell cues (HAVDI) and MSCs were observed to form highly elongated structures in RGD containing hydrogels (α=0.56±0.05), whereases collapsed structures were observed within HAVDI containing hydrogels (α=0.39±0.04). Finally, cytokine secretion was investigated, and a global increase in secreted cytokines was observed for collapsed structures compared to elongated. Taken together, this study presents a novel method to characterize cellular interactions within a stress relaxing hydrogel where altered cluster morphology imparts changes to cluster secretory profiles.

Polymer Brushes Synthesized by the "Grafting-through" Approach: Characterization and Scaling Analysis.

In this study, a combined morphological and scaling analysis of brushes synthesized by the "grafting-through" method was performed, and the possibility of regulation of the thickness was revealed on an example of polyacrylamide brushes. The chemical composition of the surface in the proposed three-step approach was analyzed by photoelectron and infrared spectroscopy. It was shown that the thickness of the dried brush can be tuned in a controlled manner by varying the polymerization temperature. The scaling dependence of the thickness of the dried brushes d on the length of the polymer d ∼ Lv was obtained by comparing reflectometry and dynamic light scattering data. The value of the exponent v = 0.82 corresponds to a rather high grafting density, exceeding the density of mushroom-like (ν ∼ 1/3) brushes and approaching the value for stretched polymer brushes (ν ∼ 1). A 10-fold increase in the polymer molecular weight leads to a slight decrease in grafting density by a factor of 2, which suggests that the "grafting-through" approach allows obtaining brushes with a high grafting density independently of attached polymer chain length. Herein, the possibility of attachment of uniform polymer brush on large substrates with this approach was demonstrated, which means the scalability of the "grafting-through" technique. The considered approach opens up a simple way for surface modification with polymer nanolayers of controlled thickness.