Spheroidal Shape Research Articles

Pillow Morphology of Bathani Volcano-sedimentary Sequence of Eastern Indian Shield: Inferences on the Geotectonic and Geo-Environments

Abstract The Palaeo-proterozoic Bathani volcano-sedimentary sequence (BVSs) at the northeastern fringe of the Central Indian Tectonic Zone (CITZ), comprises three distinct litho-domains: (i) intrusive granitoid, having xenoliths of basalt, pyroxenite-gabbro-anorthosite suits (Northern Domain), (ii) low-grade volcano-sedimentary sequence along with concordant mafic-ultramafic intrusion (Central Domain) and (iii) folded clastic metasedimentary rocks (Southern Domain). The granitoid is intruded into the Central Domain, where pillow basalt with primary structure is well exposed. The volcanological and morphometric study of the pillows of Central Domain is attempted to understand the physicochemical characteristics and tectonic setup of the magma emplacement. The pillows are small to medium normal-sized with spheroidal, lozenge, and tubular shapes and preserve the primary features like radial and concentric cracks, selvage, pipe vesicles, voids, drain away cavities, way-up features, etc. A low-viscosity magma outpouring over a steep to moderate depositional slope is being deciphered from the morphological study of pillows. The stretching and fast-spreading growth mechanisms with low effusion under a rapid cooling rate have been inferred for these pillows. The morphological features of the rock types and pillows of the BVSs suggest a shallow water (<1000m) divergent rift basin of the back-arc tectonic setting. The trace elemental discrimination plots support the basaltic composition of pillows with E-MORB and back-arc basin environment. The lithological setup, tectonic setting, and regional correlation of BVSs advocate it as an eastern continuation of the Palaeo-proterozoic Mahakoshal belt within the Son Narmada Lineament (SNL) zone of CITZ.

Tamoxifen Upregulates Collagenase Gene Expression in Human Dermal Fibroblasts.

Tamoxifen is a known inhibitor of fibroblast transforming growth factor beta biosynthesis and wound scar formation. Tamoxifen is also known to be an estrogen antagonist and protein kinase C (PKC) inhibitor. Cells treated with tamoxifen and other PKC/calmodulin inhibitors depolymerize their membrane focal adhesion complexes and cytoskeletal protein structures. These effects result in substrate detachment, cell shape rounding, and upregulation of collagenase synthesis and extracellular matrix degradation. The purpose of our study was to test the hypothesis that tamoxifen treatment of human foreskin fibroblasts results in alteration of cytoskeletal protein organization, cell detachment and rounding, and increased collagenase synthesis similar to known PKC/calmodulin inhibitors such as H-7. We characterized the effects of PKC/calmodulin inhibitors tamoxifen and H-7 on human dermal fibroblast morphology, cytoskeletal protein organization, and collagenase gene expression in monolayer culture and within collagen gels. We found that fibroblasts responded to tamoxifen by initiation of actin filament depolymerization followed by alteration from spindle to spheroidal shapes. This change in cell shape led to increased collagenase synthesis in cells treated with either tamoxifen or H-7 compared with controls. There was also a 23% increase of hydroxyproline release from tamoxifen-treated fibroblast-populated collagen matrices. Tamoxifen may reduce scarring by inhibiting fibroblast PKC/calmodulin activity, which down-regulates pro-fibrotic transforming growth factor beta signaling and upregulates collagenase production. These effects mimic those of the known PKC/calmodulin inhibitor H-7. Overall, these findings suggest that tamoxifen and its analogues are promising agents for clinical investigation as small molecule regulators of fibrosis and scarring disorders.

Fibroblast growth factor-induced lens fiber cell elongation is driven by the stepwise activity of Rho and Rac.

The spheroidal shape of the eye lens is crucial for precise light focusing onto the retina. This shape is determined by concentrically aligned, convexly elongated lens fiber cells along the anterior and posterior axis of the lens. Upon differentiation at the lens equator, the fiber cells increase in height as their apical and basal tips migrate towards the anterior and posterior poles, respectively. The forces driving this elongation and migration remain unclear. We found that, in the mouse lens, membrane protrusions or lamellipodia are observed only in the maturing fibers undergoing cell curve conversion, indicating that lamellipodium formation is not the primary driver of earlier fiber migration. We demonstrated that elevated levels of fibroblast growth factor (FGF) suppressed the extension of Rac-dependent protrusions, suggesting changes in the activity of FGF controlling Rac activity, switching to lamellipodium-driven migration. Inhibitors of ROCK, myosin and actin reduced the height of both early and later fibers, indicating that elongation of these fibers relies on actomyosin contractility. Consistent with this, active RhoA was detected throughout these fibers. Given that FGF promotes fiber elongation, we propose that it does so through regulation of Rho activity.

Real-time structural signatures of protein allostery by electrically- and mechanically-coupled sensing

Accurate detection and identification of conformational evolutions are essential to describe the micro-structural mechanisms of protein allostery. Here we establish an approach by integrating nanopore sensing technique with atomic force microscopy, based on molecular dynamics simulations. A theoretical method is further developed to real-time estimate the low-resolution structures of those evolved conformations. Tests for the forced allostery of αXβ2 integrin, a typical protein with multiple functional states, demonstrate that the spheroidal shape identifiers of those intermediate conformers present sufficient sensitivity to resolve two allosteric patterns of αXβ2 from bent-down to stand-up states under the nanopore confinement. The strong steric confinement from the nanopore restricts the geometric displacements of key domains in conformational extension dynamics, thereby increasing the intramolecular interaction energy barrier to be overcome for standing. Prolongation of the neck-shoulder region of αXβ2 and opening at the thigh-calf joint form a competitive compensation for the stretched height, resulting in two tendentious allosteric patterns under various confined diameters and steered speeds. Thus, this study proposes a new method to real-time visualize the conformational dynamics during protein allostery, favoring to depict structural characteristics for the conformations of those transient states and evaluate the impacts of the nanopore confinement on protein allostery.

Motion of microswimmers in cylindrical microchannels.

Biological and artificial microswimmers often have to propel through a variety of environments, ranging from heterogeneous suspending media to strong geometrical confinement. Under confinement, local flow fields generated by microswimmers, and steric and hydrodynamic interactions with their environment determine the locomotion. We propose a squirmer-like model to describe the motion of microswimmers in cylindrical microchannels, where propulsion is generated by a fixed surface slip velocity. The model is studied using an approximate analytical solution for cylindrical swimmer shapes, and by numerical hydrodynamics simulations for spherical and spheroidal shapes. For the numerical simulations, we employ the dissipative particle dynamics method for modelling fluid flow. Both the analytical model and simulations show that the propulsion force increases with increasing confinement. However, the swimming velocity under confinement remains lower than the swimmer speed without confinement for all investigated conditions. In simulations, different swimming modes (i.e. pusher, neutral, puller) are investigated, and found to play a significant role in the generation of propulsion force when a swimmer approaches a dead end of a capillary tube. Propulsion generation in confined systems is local, such that the generated flow field generally vanishes beyond the characteristic size of the swimmer. These results contribute to a better understanding of microswimmer force generation and propulsion under strong confinement, including the motion in porous media and in narrow channels.

Analyzing the early impact dynamics of single droplets impacting onto wetted surfaces

Single droplet impacts onto thin wall-films are a common phenomenon in many applications. For sufficiently high impact velocities, the droplet impact process consists of three phases, i.e., initial contact stage, droplet deformation with radial momentum transfer inducing an upward rising lamella, and crown propagation. Here, we present the results of a combined numerical and experimental study focusing on the early dynamics of the impact process. Specifically, the effects of the initial droplet shape, wall-film thickness, and contact line motion are analyzed. Prior to impact, an oblate spheroidal droplet shape was observed. Using direct numerical simulation, we show that the droplet shape affects the impact dynamics only during the first two phases, as it is one of the key parameter influencing the correct prediction of the impact zone. The contact line propagation is described by a square-root-time dependence R¯CL=ατ for both, dry and wetted surfaces. On dry surfaces, the advancement of the contact line is determined by the rolling motion of the truncated droplet. On wetted surfaces, the value of the α-parameter is controlled by two concurrent effects, namely, rolling motion and wall-film inertia. For impact onto thin films, the rolling motion prevails. With increasing wall-film height, the droplet penetrates into the soft substrates and wall-film inertia becomes the controlling factor. These insights into the early impact dynamics on wetted surface are important for the formulation of a unified modeling approach.

Evaluation of superficial xenograft volume estimation by ultrasound and caliper against MRI in a longitudinal pre-clinical radiotherapeutic setting.

Accurate tumor volume estimation is important for evaluating the response to radionuclide therapy and external beam radiotherapy as well as to other pharmaceuticals. A common method for monitoring the growth of subcutaneous tumors in pre-clinical models and assessing the treatment response is to measure the tumor length and width by external calipers to estimate its volume. This procedure relies on an assumption of a spheroidal tumor shape wherein the tumor depth equals the width and can yield considerably inaccuracies. Ultrasound imaging is a non-invasive technique that can measure all three axes of the tumor and might be an alternative to caliper measurement with potentially greater accuracy and comparable ease-of-use and throughput. Both 2D and 3D ultrasound imaging are possible, the former offering short scan times without the need for anesthesia and heating-valuable factors for longitudinal studies in large animal cohorts. Nevertheless, tumor volume estimation accuracy by 2D ultrasound imaging has seen limited investigation. In this study we have evaluated the accuracy of tumor volume estimation by caliper and 2D ultrasound with comparisons to reference measurements by magnetic resonance imaging (MRI) in a pre-clinical model of prostate cancer treated with either external beam radiotherapy, radionuclide therapy, or no treatment. Tumor volumes were measured longitudinally in 29 mice by caliper, ultrasound, and MRI before and after external beam radiotherapy, [177Lu]Lu-PSMA-617 radionuclide therapy, or no treatment. Caliper measurements had a marked bias, overestimating the tumor volumes by a median of 150% compared to MRI. Ultrasound measurements were markedly more accurate, with a median bias of -21% compared to MRI. Ultrasound imaging is a reliable and accurate method for tumor volume estimation in pre-clinical models of radiotherapy, whereas caliper measurements are prone to overestimation.

A taxonomic revision of Rhizophora L. (Rhizophoraceae) in Thailand.

A taxonomic revision of Rhizophora L. (Rhizophoraceae) in Thailand is presented. Two species, R. apiculata Blume and R. mucronata Poir., are enumerated with updated morphological descriptions, illustrations and a taxonomic identification key, together with notes on distributions, habitats and ecology, phenology, conservation assessments, etymology, vernacular names, uses, and specimens examined. Three names in Rhizophora, are lectotypified: R. apiculata and two associated synonyms of R. mucronata (i.e., R. latifolia Miq. and R. macrorrhiza Griff.). R. longissima Blanco, a synonym of R. mucronata, is neotypified. All two Rhizophora species have a conservation assessment of Least Concern (LC). Based on the morphological identification, these two species can be distinguished from one another by the shape and width of the leaf laminae and the length of a terminal stiff point of the leaf laminae; the type and position of the inflorescences and the number of flowers per inflorescence; the character and color of the bracteoles; the presence or absence of the flower pedicels; the shape of the mature flower buds; the shape, color, and texture of the sepals; the shape, character, and the presence or absence of hairs of the petals; the number of stamens per flower; the size of the fruits; the color and size of the hypocotyls; the color and diameter of the cotyledonous cylindrical tubes; and the color of the colleters and exudate. The thick cuticles, sunken stomata, large hypodermal cells, and cork warts are adaptive anatomical features of leaves in Rhizophora that live in the mangrove environments. The pollen grains of Thai Rhizophora species are tricolporate, prolate spheroidal or oblate spheroidal shapes, small-sized, and reticulate exine sculpturing.

Impact of 17β-Estradiol on the Shape, Survival, Osteogenic Transformation, and mRNA Expression of Gingiva-Derived Stem Cell Spheroids.

Background and Objectives: Mesenchymal stem cells hold promise for tissue regeneration, given their robust growth and versatile differentiation capabilities. An analysis of bone marrow-sourced mesenchymal stem cell proliferation showed that 17β-estradiol could enhance their growth. This study aims to investigate the influence of 17β-estradiol on the shape, survival, osteogenic differentiation, and mineralization of human mesenchymal stem cells. Materials and Methods: Spheroids made from human gingiva-derived stem cells were cultivated with varying concentrations of 17β-estradiol: 0, 0.01, 0.1, 1, and 10 nM. Morphology was assessed on days 1, 3, and 5. The live/dead kit assay was employed on day 3 for qualitative cell viability, while cell counting kit-8 was used for quantitative viability assessments on days 1, 3, and 5. To evaluate the osteogenic differentiation of the spheroids, a real-time polymerase chain reaction assessed the expressions of RUNX2 and COL1A1 on day 7. Results: The stem cells formed cohesive spheroids, and the inclusion of 17β-estradiol did not noticeably alter their shape. The spheroid diameter remained consistent across concentrations of 0, 0.01, 0.1, 1, and 10 nM of 17β-estradiol. However, cellular viability was boosted with the addition of 1 and 10 nM of 17β-estradiol. The highest expression levels for RUNX2 and COL1A1 were observed with the introduction of 17β-estradiol at 0.1 nM. Conclusions: In conclusion, from the results obtained, it can be inferred that 17β-estradiol can be utilized for differentiating stem cell spheroids. Furthermore, the localized and controlled use, potentially through localized delivery systems or biomaterials, can be an area of active research. While 17β-estradiol holds promise for enhancing stem cell applications, any clinical use requires a thorough understanding of its mechanisms, careful control of its dosage and delivery, and extensive testing to ensure safety and efficacy.

Evaluation of pore and fiber distribution characteristics of hybrid fiber reinforced lightweight aggregate concrete using X-ray computed tomography

The contribution of lightweight aggregate (LWA) and fibers to the mechanical performance of concrete is still controversial due to the unclear understanding of the enhancing mechanism. Clarifying pore structure and fiber orientation characteristics is the key to it. In this study, pore characteristics and fiber distribution properties as well as their correlations with concrete strengths were evaluated. To separate the effect of LWA's internal pores and LWA's internal curing, pore parameters were calculated in two ways, i.e., containing and excluding LWA. Results show that the internal pores of LWA are detrimental to the overall pore structure while the internal curing optimizes the pore distribution by decreasing porosity and pore size and increasing sphericity. Pore sphericity has a positive linear correlation with compressive strength only when LWA's internal pores are included. When the inner pores of LWA are excluded, sphericity is positively correlated with flexural strength. It indicates that LWA's internal pores have a more significant effect on compressive strength while LWA's internal curing effect has a more prominent impact on flexural strength. In addition, adding fibers benefits pore characteristics given that more pores are in the spheroid shape with higher sphericity. Furthermore, fibers are well distributed in this study with a mean orientation coefficient of 0.59, which exhibits a positive correlation with flexural strength but an insignificant correlation with compressive strength.

Mineralogy and Conditions of Formation Genesis of Aggregates of Natural and Sulfide Minerals of the Poldnevskoe Demantoid Deposit (Middle Urals)

Polymineral aggregates of rounded shapes (“nodules”) composed of native and sulfide minerals of Cu, Ni, Fe, Ag, and other elements from vein magnetite–calcite–chrysotile rocks with jewelry demantoid in the Korkodinskoe hypermafic massif are described. A common feature of the six identified types of native sulfide nodules, composed of native copper, heazlewoodite, pentlandite, cuprite, and other native sulfide minerals, is their spheroidal shape, which makes them similar to individual grains of other gangue minerals (calcite, magnetite, etc.). In heazlewoodite–pentlandite nodules, specific symplectites of mercuric silver and nickel copper in heazlewoodite, as well as awaruite in Co–pentlandite, were found. The matching set of ore minerals in the host serpentinite vein mass (native copper, mercuric silver, heazlewoodite, pentlandite, awaruite) and nodules from the vein material indicates their genetic connection and the conjugation of demantoid mineralization with the evolving processes of serpentinization. It was established that the nodules formed at temperatures below 380°C under reducing conditions at very low sulfur fugacity values (10–17–10–27 bar) and oxygen (10–30 bar at 200°C to 10–21 bar at 350°C). For heazlewoodite–pentlandite nodules, such conditions persisted throughout the entire time of their formation, while, for other nodules, the reducing conditions of early parageneses were replaced by oxidative conditions in late parageneses, which is recorded by the replacement of native copper with cuprite. It is assumed that the features of the morphology and structure of native sulfide nodules and the presence of symplectite intergrowths of ore minerals in them are associated with specific conditions created during the decompression of the crust-mantle mixture rising to the surface in the fault zone. The source of the metals was a deep, high-temperature fluid interacting with mafic and ultramafic rocks under reducing conditions at a low water-to-rock ratio.

Fabrication of a Three-Dimensional Spheroid Culture System for Oral Squamous Cell Carcinomas Using a Microfabricated Device.

Cancer stem cells (CSCs) are considered to be responsible for recurrence, metastasis, and resistance to treatment in many types of cancers; therefore, new treatment strategies targeting CSCs are attracting attention. In this study, we fabricated a polyethylene glycol-tagged microwell device that enabled spheroid formation from human oral squamous carcinoma cells. HSC-3 and Ca9-22 cells cultured in the microwell device aggregated and generated a single spheroid per well within 24-48 h. The circular shape and smooth surface of spheroids were maintained for up to five days, and most cells comprising the spheroids were Calcein AM-positive viable cells. Interestingly, the mRNA expression of CSC markers (Cd44, Oct4, Nanog, and Sox2) were significantly higher in the spheroids than in the monolayer cultures. CSC marker-positive cells were observed throughout the spheroids. Moreover, resistance to cisplatin was enhanced in spheroid-cultured cells compared to that in the monolayer-cultured cells. Furthermore, some CSC marker genes were upregulated in HSC-3 and Ca9-22 cells that were outgrown from spheroids. In xenograft model, the tumor growth in the spheroid implantation group was comparable to that in the monolayer culture group. These results suggest that our spheroid culture system may be a high-throughput tool for producing uniform CSCs in large numbers from oral cancer cells.

Non thermal plasma synthesis of ZnO nanoparticles and their corrosion inhibition activity on XC70 mild steel pipeline in 1 M HCl acidic medium

This paper investigates the inhibitory efficiency of zinc oxide nanoparticles (ZnO Nps) as an eco-friendly inhibitor against the corrosion of XC70 mild steel pipelines in a 1 M HCl acidic medium. The ZnO Nps were synthesized using non thermal plasma, in particular the gliding arc discharge-assisted (GAD) method, a chemical solvent free and safe approach that utilizes humid air as the vector gas and distilled water as the solvent. Characterization techniques such as DLS, EDX, SEM, and XRD confirmed the positive zeta potential, hexagonal wurtzite structure, spheroidal shape, and median particle size of 65.6 nm for the synthesized ZnO Nps, respectively. To evaluate the corrosion inhibition efficiency, investigations were conducted utilizing electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) techniques at varying temperature range (298–333K). Results showed that increasing the concentration of ZnO Nps improved their ability to inhibit corrosion, with an optimum concentration of 70 mg/L achieving a high effectiveness of 90.71 % at ambient temperature. SEM analysis confirmed the formation of a protective barrier film on the inhibited substrate, effectively hindering the diffusion of corrosive ions. Furthermore, the DFT method was employed to examine the corrosion mitigation mechanism. These results demonstrate the significant inhibiting properties of ZnO Nps in preventing corrosion of XC70 mild steel in a 1 M hydrochloric acid environment.

Study on the Electrochemical Properties of Mg1−xYxCO3@2MnCO3 Doped at Magnesium Site and the Effect of Manganese Carbonate and Magnesium Carbonate Composite Material Modified by Zn Doping

Mangan-based zinc ion batteries have received increasing attention due to their high theoretical capacity and environmental friendly properties. However, the capacity attenuation of manganese-based materials during the charge-discharge cycle seriously affects the improvement of electrochemical performance. In order to solve the problem of capacity attenuation, magnesium carbonate material was combined with manganese carbonate material, and the magnesium site was doped and modified. In this paper, the Mg0.98Zn0.02CO3@2MnCO3 material was selected out from all the synthesized materials due to its stable electrochemical performance, its capacity is as high as 283.65 mAh g−1 under the current density of 100 mA g−1. Subsequently, the characterization test was carried out to further discover the composition of the material. It can be observed from SEM that the material has two main structures: cube shape and spheroid shape, and nanowires grow on the surface of the cube structure. Moreover, the EDS and XPS tests were conducted which could prove the elements contained in Mg0.98Zn0.02CO3@2MnCO3 material were consistent with the valence states of the elements in manganese carbonate and magnesium carbonate. The further infrared and Raman tests showed that the functional groups in the material were also consistent with the molecular formula. According to the XRD test result, no obvious impurity peak can be oberved, indicating the electrochemical performance of Mg0.98Zn0.02CO3@2MnCO3 composite material synthesized by hydrothermal method is relatively stable.

Microswimmer trapping in surface waves with shear

Many species of phytoplankton migrate vertically near the surface of the ocean, in search of either light or nutrients. These motile organisms are affected by ocean surface waves. We derive a set of wave-averaged equations to describe the motion of microswimmers with spheroidal body shapes that includes several additional effects, such as gyrotaxis, settling and wind-driven shear. In addition to the well-known Stokes drift, the microswimmer trajectories depend on their orientation in a way that can lead to trapping at a particular depth; this in turn can affect transport of organisms, and may help explain observed phytoplankton layers in the ocean.

Physically-based simulation of elastic-plastic fusion of 3D bioprinted spheroids

Spheroids are microtissues containing cells organized in a spherical shape whose diameter is usually less than a millimetre. Depending on the properties of the environment they are placed in, some nearby spheroids spontaneously fuse and generate a tissue. Given their potential to mimic features typical of body parts and their ability to assemble by fusing in permissive hydrogels, they have been used as building blocks to 3D bioprint human tissue parts. Parameters controlling the shape and size of a bioprinted tissue using fusing spheroid cultures include cell composition, hydrogel properties, and their relative initial position. Hence, simulating, anticipating, and then controlling the spheroid fusion process is essential to control the shape and size of the bioprinted tissue. This study presents the first physically-based framework to simulate the fusion process of bioprinted spheroids. The simulation is based on elastic-plastic solid and fluid continuum mechanics models. Both models use the ‘smoothed particle hydrodynamics’ method, which is based on discretizing the continuous medium into a finite number of particles and solving the differential equations related to the physical properties (e.g. Navier–Stokes equation) using a smoothing kernel function. To further investigate the effects of such parameters on spheroid shape and geometry, we performed sensitivity and morphological analysis to validate our simulations with in-vitro spheroids. Through our in-silico simulations by changing the aforementioned parameters, we show that the proposed models appropriately simulate the range of the elastic-plastic behaviours of in-vitro fusing spheroids to generate tissues of desired shapes and sizes. Altogether, this study presented a physically-based simulation that can provide a framework for monitoring and controlling the geometrical shape of spheroids, directly impacting future research using spheroids for tissue bioprinting.

Detection of NO2- with a colorimetric sensor based on etching Au NBPs

Nitrite (NO2-) in water and food is a potential threat to the environment, human health, and other living organisms. Therefore, the detection of NO2- is highly essential. Herein, a simple and fast colorimetric method for NO2- detection is realized based on the etching of non-modified gold nanobipyramids (Au NBPs), which results in the blue-shift of longitude local surface plasmon resonance (LSPR) peak and obvious color changes. The NO2- was detected through this method with a linear response ranging from 2.0 to 20 μM, a limit of detection (LOD) of 0.17 μM and a naked eye LOD of 6.0 μM under the optimal conditions. The LOD is sufficiently for the detection of NO2- in food in real life applications. During the detection, the morphology of Au NBPs generally changes from the bipyramid shape to the rice shape, and then to the final spheroid shape with increasing NO2- concentration. The feasibility of this method was verified in real samples with good recovery. Compared with other methods, this colorimetric sensor has advantages such as its low cost, excellent sensitivity and selectivity, and the most importantly, it can be applied to visually detect NO2-.

Self-aggregation of cationic gemini surfactants with amide groups in the spacer and variable alkyl chain length

AbstractSynthesis, aggregation parameters and antimicrobial activity of novel cationic gemini surfactants with two amide groups in gemini spacer structure and a variable number of carbon atoms in alkyl tails ranging from 12 to 15 are reported. The critical micelle concentration of gemini surfactants was determined using surface tension and electrical conductivity methods. The cmc values were found in the range 0.83 to 0.06 mM. The interfacial area, micelle ionisation degree and the Gibbs free energy per molecule and alkyl chain were calculated from the surface tension and conductivity curves. Particle size analysis using the dynamic light scattering method confirmed the formation of small spherical micelles 6–7 nm large in size for gemini surfactants with 12 and 13 carbon atoms in the alkyl chain. A large size above 50 nm was found for the aggregates composed of long-chain gemini molecules with 14 and 15 carbon atoms. The zeta potential of gemini surfactants shows a continuous increase with the increasing alkyl chain length. Micelle aggregation number of gemini surfactants correlates well with the hydrodynamic size data. Small aggregation number values were found for short-chain gemini molecules with 12 and 13 carbon atoms in the alkyl chain. Long-chain gemini molecules with 14 and 15 carbon atoms exhibit aggregate growth represented by an increase in the aggregation number values while maintaining the spherical or spheroidal shape of micelles. The investigations of antimicrobial activity against Gram-positive bacteria, Gram-negative bacteria and yeast indicate the increasing antimicrobial efficiency towards the short-chain surfactant with 12 carbon atoms in the alkyl chain. A possible cut-off effect presence is proposed to explain the dependence of antimicrobial activity on the surfactant alkyl tail length.

Flexible Microcircuit of a Liquid Metal Deposit Layer

AbstractLiquid metal (LM) is of great use in many fields (e. g., sensors, biology, electronic circuits). With special mobility, high surface tension and excellent electrical conductivity, it can play a role in the field of flexible electronics. Due to its surface tension, it easily shrinks into a spheroid shape. Especially under the same current condition, the shrinkage of the volume will lead to open circuit, so it is very difficult to produce stable liquid metal ultrathin, ultrafine wire, which has become a barrier limiting the use of liquid metal. In this work, LM is mixed with polydimethylsiloxane to form a micrometer‐thick conductive layer by free deposition. The LM is located inside the polymer holes. Not only that, microcircuits are also mapped on the surface of LM deposits. It not only has excellent electrical conductivity, but also has good flexibility. This work explores a simple method to produce a ultrathin conductive film and reduce the size of electronic components, which has potential applications in integrated circuits.

Effect of duration and type of grinding on the particle size distribution and microstructure of natural pumice with low pozzolanic reactivity

Pumice, with low pozzolanic reactivity, was ground for 1, 3, and 6 h with a laboratory ball mill in dry conditions and it was ground for 1 h in wet conditions via an industrial-scale ball mill. Based on derivative particle distribution, grinding for longer periods led to the disappearance of bimodal distribution and the development of unimodal distribution. Furthermore, the phase characterization, assessed through XRD, demonstrated appreciable changes in intensities of the peaks of quartz and dachiardite. The extension of grinding time resulted in a significant uptake at the early-age lime consumption and evolution of hydration heat. According to SEM images, the number of particles between 10 and 20 μm was less in the powder ground for 3 and 6 h. Moreover, it was found that the prismatic shapes of raw pumice tended to transform to spheroid shapes after prolonged grinding, and the smooth surfaces of pumice particles became more rugged.