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Some fungi have demonstrated the ability to adapt rapidly to changing environments by exhibiting morphological plasticity, a trait influenced by species and environmental factors. Here, an anamorphic yeast strain IOJ-3 exhibited unique sectorization characteristics, naturally producing diverse filamentous sectors when cultivated on potato dextrose agar (PDA) medium or natural culture medium for durations exceeding 13 days. The strain IOJ-3 and its filamentous sectors were identified as Dothiora sorbi. The morphology of the sectors was consistent and heritable. The life cycle of strain IOJ-3 was investigated through microscopic observation, emphasizing the development of conidiogenous cells as a crucial stage, from which filamentous sectors originate. Some physiological characteristics of IOJ-3 and filamentous sectors are compared, and strain IOJ-3 has a higher antibiotic tolerance than two filamentous sectors, IOJ-3a expands faster on the culture medium, and IOJ-3b can penetrate cellophane. A transcriptomic analysis was conducted to investigate the differentially expressed genes between the yeast form IOJ-3 and its two filamentous sectors, revealing a total of 594 genes that exhibited consistent differential expression relative to IOJ-3, including 44 silencing genes in IOJ-3 that were activated. Gene Ontology analysis indicated that these differentially expressed genes were primarily associated with the cellular component category. Furthermore, adding 5-Azacytidine accelerated filamentous sectorization and increased the proportion of filamentous cells of strain IOJ-3 in PD liquid media, suggesting that the filamentous sectorization observed in strain IOJ-3 is linked to processes of DNA demethylation. In conclusion, this study sheds light on the biological characteristics of D. sorbi regarding morphological transitions and provides substantial direction for exploring genes related to fungal filamentous development. [ABSTRACT FROM AUTHOR]

• Investigations of results obtained by KMC simulations during heteroepitaxial growth. • EAM Method is used to compute the activation barriers of different diffusion processes. • All process diffusion is modeled by Anisotropic bond breaking model (ABBM). • Growth conditions effect the surface morphologies evolution for both systems Ag and Au on Cu(1 1 0). In this work, different coverages (1% ≤ coverage ≤ 20%) are studied during the growth of Ag and Au monolayers on the Cu (1 1 0) surface using kinetic Monte Carlo simulations (kMC). The results have shown that as coverage increases, the likelihood of an isolated adatom connecting to another adatom or island also increases. Thus, the phenomenon by which an adatom disintegrates from one island to another becomes significant. Molecular statics method is used to calculate the activation energy barriers of several diffusion processes in the framework of the Embedded-Atom method (EAM). These diffusion processes are implemented in the kinetic Monte Carlo (kMC) simulations under the Anisotropic Bond-Breaking Model (ABBM) model. The results show that as the coverage increases, 1D clusters are observed at 200 K. However, the transition from compact 1D (at 200 K) to 2D islands has been observed for relatively high temperatures (300 K and 400 K). [ABSTRACT FROM AUTHOR]

Candida albicans is a polymorphic opportunistic commensal that causes both superficial and systemic fungal infections especially in immunocompromised patients. Biologically synthesized silver nanoparticles (AgNPs) have emerged as potential antifungal agents. The present work evaluates the antifungal activity of Artemisia annua synthesized AgNPs against three Candida species (C. albicans ATCC 90028, C. tropicalis ATCC 750 and C. glabrata ATCC 90030). The in vitro effect of AgNPs was investigated for fungal growth, sterol content, secretion of hydrolytic enzymes and yeast-to-hyphal transition. The green synthesized AgNPs were effective against all the three species with minimum inhibitory concentration (MIC) in the range 80–120 μgml−1. Candida glabrata showed greater sensitivity for AgNPs followed by Candida tropicalis and C. albicans. AgNPs at 4MIC were as effective as fluconazole (FLC) and caused only 5% haemolysis while FLC caused 50% haemolysis at the same concentration. The secretion of hydrolytic enzymes was the lowest in case of AgNP exposed C. glabrata. Yeast-to-hyphal transition was significantly reduced in treated C. albicans cells and showed disfigured morphology in SEM images. The decrease in ergosterol content was slightly higher (94%) in both C. glabrata and C. tropicalis in comparison to C. albicans (69%). Green synthesized AgNPs thus have immense potential as an antifungal and can play a crucial role in the management of Candida infections especially those caused by C. glabrata. [ABSTRACT FROM AUTHOR]

Loureirin A is a major active component of Draconis sanguis , a traditional Chinese medicine. This work aimed to investigate the activity of loureirin A against Candida albicans biofilms. 2, 3-Bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT)reduction assay and scanning electron microscopy were used to investigate the anti-biofilm effect. Minimal inhibitory concentration testing and time-kill curve assay were used to evaluate fungicidal activity. Cell surface hydrophobicity (CSH) assay and hyphal formation experiment were respectively carried out to investigate adhesion and morphological transition, two virulence traits of C. albicans. Real-time RT-PCR was used to investigate gene expression. Galleria mellonella − C. albicans and Caenorhabditis elegans-C. albicans infection models were used to evaluate the in-vivo antifungal effect. Human umbilical vein endothelial cells and C. elegans nematodes were used to evaluate the toxicity ofloureirin A. Our data indicated that loureirin A had a significant effect on inhibiting C. albicans biofilms, decreasing CSH, and suppressing hyphal formation. Consistently, loureirin A down-regulated the expression of some adhesion-related genes and hypha/biofilm-related genes. Moreover, loureirin A prolonged the survival of Galleria mellonella and Caenorhabditis elegans in C. albicans infection models and exhibited low toxicity. Collectively, loureirin A inhibits fungal biofilms, and this effect may be associated with the suppression of pathogenic traits, adhesion and hyphal formation. [ABSTRACT FROM AUTHOR]

Pluronics have emerged as a potential agent for solubilizing a variety of lipophilic bioactive molecules, but how these solubilizates affect the morphology of Pluronic micelles still remains poorly understood. In this work, the morphological transition of Pluronic P123 micelles induced by three gallate homologs with different alkyl chain length, namely methyl gallate (MG), propyl gallate (PG) and octyl gallate (OG) has been comprehensively investigated by combination of dynamic light scattering (DLS), cryogenic transmission electron microscopy (Cryo-TEM), 1H NMR and atom-scale molecular dynamic simulations. It is found that addition of the three gallate significantly increases the micellar sizes and polydispersities. Cryo-TEM measurements reveal that spherical P123 micelles form micellar clusters in the presence of PG and short rod micelles with OG, while MG do not change the micellar morphology. Qualitative interactions between various gallate and P123 micelle are determined by NMR experiments. It is demonstrated that the different locations of various gallate in the micelles are governed by the balance of hydrophobic interaction and hydrogen bonding, which consequently leads to the varying micellar morphologies. The experimental results are further confirmed by dynamic molecular stimulation. We also show that the intensity of Pluronic-gallate interaction increases with the hydrophobicity of the gallate, indicating that hydrophobic interaction is more important on the morphological transition. Finally, the mechanism of morphological transition induced by various gallate are discussed and proposed, where the nature of formation of micellar cluster induced by PG is particularly emphasized. [ABSTRACT FROM AUTHOR]

Abstract The aqueous solutions of PEO-PPO-PEO type triblock copolymers (Pluronic® P123, P103 and P105) with variations in their total molecular weight and block contribution are investigated for encapsulation of drugs. Two drugs, namely Aspirin (AS) and 5-Methyl Salicylate (MS) having different partition coefficient was studied. The changes in size and micellar dynamics due to formation of drug-polymer complexes are investigated using dynamic light scattering (DLS), dynamic surface tension (DST), Nuclear Magnetic Resonance (NMR) and Small angle neutron scattering (SANS) measurements. Increase in apparent hydrodynamic diameter (D h) measured by DLS suggests the growth of micelles, which is equally supported by calculated micellar parameters from SANS measurements. The solubilization of drugs within micelles alters the diffusivity of the monomers due to stronger hydrophobic forces leading to highly stable aggregates as concluded by dynamic surface tension measurements. The significant increase in micellar size was noticed in presence of MS, while AS had less prominent effect on micellar growth. The preferential partitioning of drug into the hydrophobic micellar core is the driving force for the possible formation of higher morphologies. The hydrophobic interactions between MS and P123 are confirmed by 1H NMR. The differences in molecular interactions leading to distinct morphological behavior are explained by the localization of drug within nanocarriers. Graphical abstract Unlabelled Image Highlights • Salicylic acid analogues affect the micellar structures of Pluronics®. • 5-Methyl salicylate exert stronger alterations compared to Aspirin. • Molecularly dissolved drug decreases diffusivity of copolymer molecules in bulk. • The SANS reveals transformation of micellar aggregates to ellipsoidal structure. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Elucidation of the effect of electrolytes towards the morphology of OTAB micelles. • Monomeric salts induce monotonous micellar swelling. • Effect of the monomeric salts has been explained by the co-sphere overlap model. • Polymeric salt induce minute micellar growth followed by phase separation. • A novel two-step model has been invoked for the polymeric salt-induced changes. Abstract The discrete effects of a series of structurally divergent monomeric viz. Sodium Chloride (NaCl), Tetra-butyl Ammonium Chloride (TBAC) and Sodium Benzoate (NaBz) and polymeric viz. Sodium Polystyrene Sulfonate (NaPSS) electrolytes towards the morphological and/or aggregation properties of Octadecyl-trimethyl Ammonium Bromide (OTAB) micelles have been quantified spectroscopically by means of the modulations of the absorption and emission spectral properties of an extrinsic anthracene-based probe 9-methyl anthroate (9-MA) within the concerned media. Further corroboration of the spectroscopic results was acquired from the non-invasive dynamic light scattering technique. The qualitatively similar mode of action of all the monomeric salts has been explained on the basis of the archetypal Israelachvili model whereas the corresponding extent of the morphological transition of the micelles, which is found to follow the order NaBz > NaCl > TBAC, has been explained invoking the co-sphere overlap model. Conversely, to explain the aggregation behaviour of the micelles in the presence of the polymeric electrolyte, a two-step model has been formulated. According to this model, at the low concentration regime, the polymeric salt is found to only neutralize the surface charge of the micelles inducing micellar growth; whereas further increment in the concentration of the polymer assists the hydrophobic association between the micelles leading to the formation of larger aggregates, eventually causing a phase separation. [ABSTRACT FROM AUTHOR]

A novel low molecular weight organogelator (LMOG) containing an azobenzene group has been designed and synthesized. Stable gels could be formed in various organic solvents. UV–Vis spectroscopy indicated that the sol-gel transition of the organogels could be reversibly tuned by UV/visible light irradiations. Importantly, scanning electron microscopy (SEM) revealed that the characteristic gelation morphologies would vary from solvents of different polarities. FT-IR, XRD and rheological measurements demonstrated that the different nanostructures in polar and non-polar solvents might result from the differences in the intermolecular hydrogen bonding, π-π stacking driving forces as well as the different stacking models for the formation of the gels. Moreover, as an efficient phase-selective gelator, this photo-switchable gel could perform as an efficient absorbent and water cleaner to remove pollutants (e.g. rhodamine B). [ABSTRACT FROM AUTHOR]

We report experimental results of time-resolved 2d-SAXS measurements for a polystyrene- block -poly(ethylene- co -butylene)- block -polystyrene (SEBS) triblock copolymer as-cast film, which was subjected to a planar flow gradually imposed in the heating process of the specimen at a ramp-up rate of 2 °C/min. Before heating, non-equilibrium spheres were formed in the specimen. At 144 °C, the spheres were found to completely transform into cylinders. Some extent of cylinder orientation (0.5 in orientation factor) was already achieved, even at that temperature the strain of the specimen was as low as 0.5. From this fact, the directional coalescence of non-equilibrium spheres along with the planar flow direction (FD) was implied. As temperature increased, it was found the progress of the cylinder orientation parallel to FD as well as the orientation of the ( 1 0 1 ¯ 0 ) planes of hexagonal lattice parallel to the substrate surface. The fraction of the peak-top intensities of the ( 1 1 2 ¯ 0 ) reflections, I ( 11 2 ¯ 0 ) / ( I ( 10 1 ¯ 0 ) + I ( 11 2 ¯ 0 ) ) , was evaluated to examine the change in the orientational state of hexagonal lattice during application of the planar flow. The fraction was found to moderately increase with strain. However, the fraction of the grains, in which the ( 1 0 1 ¯ 0 ) planes are parallel to the specimen surface, is as low as 0.07 even at the highest strain state. [ABSTRACT FROM AUTHOR]

• A new criterion to govern faceted to non-faceted (f - nf) morphology presented. • A foreknowledge of the solidification velocity at which f - nf transition become eminent for pure materials. • The transition criterion rest on the Cahn theory of interface structure and the theory of liquid–solid transition by the maximum entropy production rate principle (MEPR). A criterion to explain the morphological growth transition from faceted to non-faceted (f - nf) morphology in the case of directional solidification is presented for pure materials. The criterion is based on the number of atomic layers at the solid–liquid interface and allows a foreknowledge of the solidification growth velocity at which f - nf transition becomes significant. The basis for the transition criterion hinges on the Cahn theory of interface structure and the theory of liquid–solid transition by the maximum entropy production rate (MEPR) principle. The criterion is tested with a number of pure materials and compared with experimental measurements for salol. The criterion fits quite well with available experimental data. [ABSTRACT FROM AUTHOR]

Structural characterization of polymeric micelles is important to understand the relation between micellar structure and properties for application in e.g. drug delivery, catalysis, and sensing. In this work we demonstrate the potential of iPAINT super-resolution microscopy for the imaging of complex coacervate core micelles (C3Ms). C3Ms are formed out of the flexible cationic diblock copolymer poly( N -methyl-2-vinyl pyridinium chloride)- b -poly(ethylene oxide) (P2MVP 29 - b -PEO 204 ) and a stiff anionic polyfluorene derivative (PF 22 ). We use iPAINT to ‘stain’ the C3Ms in a simple, non-covalent fashion to image the morphology of individual micelles. Spherical architectures are detected at low concentrations (< 0.07 mM), while more elongated, non-spherical structures with axial ratios υ ≤ 2.3 are adopted at higher concentrations (> 0.14 mM). The observed ellipsoid-like morphology is unusual and furthermore unexpected for C3Ms of copolymers with a considerably longer corona-forming hydrophilic block than the core-forming ionic block. We attribute the observed morphological transition from spherical to ellipsoidal micelles as concentration rises to the stiffness of the conjugated polyfluorene. [ABSTRACT FROM AUTHOR]

The easy-to-use method for detecting uric acid in human serum is of great importance because of its crucial role in physiological and pathological processes. Herein, a simple and effective strategy was designed for colorimetric sensing of uric acid using the morphological transition of Ag nanoprisms. In the presence of uricase, uric acid was oxidized to produce H 2 O 2 . Subsequently, the morphology of Ag nanoprisms changed from triangle to round by etching of H 2 O 2 , leading to a more than 120 nm blue shift of surface plasmon resonance spectral band. The color change from pale blue to purple related to concentration change of uric acid can be judged by naked eyes. A linear relationship between the blue shift of peak of Ag nanoprisms and uric acid concentration ranged from 1.0 to 40 μM. The detection limit of uric acid was 0.7 μM. Some potential interferents (e.g., ascorbic acid, glucose, dopamine, hypoxanthine and various amino acids) in human serum showed no interference. Serum samples could be directly added into Ag nanoprism–uricase sensing system, and the assay can be completed within one hour. The proposed sensor was successfully applied for detecting uric acid in human serum with the recoveries over 95%. The obtained results are in agreement with those measured by biochemistry analyzer with the average relative error of 5.1%. The Ag nanoprism–uricase sensor offers advantages of high selectivity and sensitivity, low-cost instruments, and rapid assay without sample pretreatment. Thus, the present uric acid sensor has great potential in applications for biochemical analysis and clinical diagnosis. [ABSTRACT FROM AUTHOR]

The unarmoured freshwater dinoflagellate Nusuttodinium (= Gymnodinium ) aeruginosum retains a cryptomonad-derived kleptochloroplast and nucleus, the former of which fills the bulk of its cell volume. The paucity of studies following morphological changes to the kleptochloroplast with time make it unclear how the kleptochloroplast enlarges and why the cell ultimately loses the cryptomonad nucleus. We observed, both at the light and electron microscope level, morphological changes to the kleptochloroplast incurred by the enlargement process under culture conditions. The distribution of the cryptomonad nucleus after host cell division was also investigated. The volume of the kleptochloroplast increased more than 20-fold, within 120 h of ingestion of the cryptomonad. Host cell division was not preceded by cryptomonad karyokinesis so that only one of the daughter cells inherited a cryptomonad nucleus. The fate of all daughter cells originating from a single cell through five generations was closely monitored, and this observation revealed that the cell that inherited the cryptomonad nucleus consistently possessed the largest kleptochloroplast for that generation. Therefore, this study suggests that some important cryptomonad nucleus division mechanism is lost during ingestion process, and that the cryptomonad nucleus carries important information for the enlargement of the kleptochloroplast. [ABSTRACT FROM AUTHOR]

Abstract: Candida albicans is an opportunistic human fungal pathogen which causes disease mainly in immunocompromised patients. Activity of hydrolytic enzymes is essential for virulence of C. albicans and so is the capacity of these cells to undergo transition from yeast to mycelial form of growth. Ocimum sanctum is cultivated worldwide for its essential oil which exhibits medicinal properties. This work evaluates the anti-virulence activity of O. sanctum essential oil (OSEO) on 22 strains of C. albicans (including a standard strain ATCC 90028) isolated from both HIV positive and HIV negative patients. Candida isolates were exposed to sub-MICs of OSEO. In vitro secretion of proteinases and phospholipases was evaluated by plate assay containing BSA and egg yolk respectively. Morphological transition from yeast to filamentous form was monitored microscopically in LSM. For genetic analysis, respective genes associated with morphological transition (HWP1), proteinase (SAP1) and phospholipase (PLB2) were also investigated by Real Time PCR (qRT-PCR). Results were analyzed using Student's t-test. OSEO inhibits morphological transition in C. albicans and had a significant inhibitory effect on extracellular secretion of proteinases and phospholipases. Expression profile of respective selected genes associated with C. albicans virulence by qRT-PCR showed a reduced expression of HWP1, SAP1 and PLB2 genes in cells treated with sub-inhibitory concentrations of OSEO. This work suggests that OSEO inhibits morphological transition in C. albicans and decreases the secretion of hydrolytic enzymes involved in the early stage of infection as well as down regulates the associated genes. Further studies will assess the clinical application of OSEO and its constituents in the treatment of fungal infections. [Copyright &y& Elsevier]

Abstract: The effect of addition of a bile salt, sodium deoxycholate (NaDC), on the morphological transition in aqueous cetyl trimethylammonium bromide (CTAB) has been studied by various macroscopic and microscopic techniques. Visual, optical density and zero-shear viscosity data of the aqueous mixtures provide some basic macroscopic information on phase behavior. Various phase transitions are observed as we increase the [NaDC] and system even passes through the precipitation region followed by an appearance of clear fluid again. Before and after precipitation region, systems show bluish appearance indicating the presence of vesicles, which was supported by rheological and dynamic light scattering data. It was interesting to note that vesicles were present in the solution when the mole fraction of one of the components was ~0.55. This suggests the requirement of the charge for vesicle formation and stabilization. NMR spectra show the peak broadening on increasing the [NaDC] in the system confirming the presence of a mixture of micelles and vesicles. The presence of vesicles in few samples of CTAB–NaDC aqueous mixture was further confirmed by polarizing and transmission electron microscopy. Bigger morphologies were observed at pH=9.2 (than in pure water). Such morphological transitions may have utility in range of areas, including viscosity enhancer, template for nanostructures and as models for biological assemblies. [Copyright &y& Elsevier]

Abstract: Paracoccidioides brasiliensis is a fungal pathogen with a broad distribution in Latin American countries. The mycelia-to-yeast morphological transition of P. brasiliensis is involved in the virulence of this pathogen, and this event is essential to the establishment of infection. Here, we report the first proteomic comparison between the mycelia, the mycelia-to-yeast transition and the yeast cells. Changes in the relative abundance of the components of the proteome during phase conversion of P. brasiliensis were analyzed by two-dimensional gel electrophoresis coupled to mass spectrometry. Using MALDI-TOF-MS, we identified 100 total proteins/isoforms. We show that 18, 30 and 33 proteins/isoforms in our map are overexpressed in the mycelia, the mycelia-to-yeast transition and in yeast cells, respectively. Nineteen proteins/isoforms did not present significant differences in the volume spots in the three analyzed conditions. The differential expression was confirmed for six different proteins by Western blot analysis. The quantitative differences observed by the proteomic analysis were correlated with the transcript levels, as determined by quantitative RT-PCR of the analyzed conditions, including conidial formation and the transition from conidia-to-yeast cells. The analysis of the functional categories to which these proteins belong provided an integrated view of the metabolic reorganization during the morphogenesis of P. brasiliensis. [Copyright &y& Elsevier]

Abstract: In this paper, a uniform calf thymus deoxyribonucleic acid (DNA) network has been constructed on a bare mica surface using a simple adsorption method. The effect of the immersion time in water on the characteristics of the morphological transitions of DNA molecules adsorbed on the mica surface was investigated by atomic force microscopy. It was found that the DNA molecules underwent conformational transitions from stretched wormlike coil to rod and to network by changing the immersion time in water and the formation mechanism was explained briefly. [Copyright &y& Elsevier]

Abstract: A lagrangian model has been developed to predict the evolution of a single equiaxed crystal moving into an infinite medium, and intended to be coupled with a macroscopic code devoted to the solidification of large cast products. A particular attention is paid to the transition from globular to dendritic crystals because both morphologies can be observed in cast products. First, the model has been compared with experiments of settling NH4Cl crystals in NH4Cl-H2O melts. Good agreements have been achieved provided that a suitable value is chosen for the stability constant of the dendrite tip growth model. The model is then applied to a multicomponent steel so as to outline the link between the morphology and the sign of the chemical segregation. Finally, the trends drawn from the model concerning the change in morphology are discussed so as to explain the concomitancy of the structural and chemical patterns observed in the equiaxed zone of heavy steel ingots. [Copyright &y& Elsevier]

Abstract: The poly(styrene)-block-poly(2-vinylpyridine)-block-poly(ethylene oxide) triblock copolymer, PS200-b-P2VP140-b-PEO590, where the subscripts refer to the average degrees of polymerisation of the constitutive blocks, has been dissolved in water/toluene mixtures with a large range of composition, i.e. in (i) toluene added with a small amount of water, (ii) water-in-toluene emulsion forming mixtures, (iii) toluene-in-water emulsion forming mixtures, and (iv) water added with a small amount of toluene. These solutions have been cast on a carbon-coated copper grid, and the morphology of the dried copolymer deposition has been observed by transmission electron microscopy. Rod-like aggregates with a core–shell–corona micellar structure are formed in cases (i) and (iv). Nevertheless, PEO is the core and PS is the corona in case (i), whereas the reverse situation prevails in case (iv). When an emulsion is the precursor of the dried copolymer aggregates, either onion-like structures (case ii) or vesicles mixed with more complex aggregates are formed (case iii). These structures are thought to reflect the self-organization of the PS200-b-P2VP140-b-PEO590 copolymer at the water/toluene interface of the water-in-toluene and toluene-in-water emulsions, respectively. [Copyright &y& Elsevier]

Abstract: Al–Bi alloys of exact monotectic composition were directionally solidified with solidification velocities from 0.3μm/s to 5μm/s and temperature gradients from 2K/mm to 6.5K/mm. At large gradients and low solidification velocities the monotectic reaction leads to Bismuth fibres in an Aluminium matrix. The Bi fibres are replaced by a string of pearls of Bi droplets at larger velocities or smaller gradients. The transition between both structures is discussed theoretically and compared with the experimental results. [Copyright &y& Elsevier]

Abstract: Morphological transition of the ABC-type triblock copolymer from lameller to tricontinuous Gyroid structure has been observed. The sample used is a symmetric poly(isoprene-block-styrene-block-2-vinylpyridine), whose volume fractions of three components are 0.26, 0.48 and 0.26, and the total molecular weight is 1.0×105. The solvent cast films were prepared and dried well, followed by annealing at 423K, the temperature well above the glass transition temperatures of three polymer components. The structural transition was investigated by varying the annealing time from 1h up to 7 days with two methods, transmission electron microscopy and small-angle X-ray scattering. It was confirmed that the as-cast film shows lamellar structure, however, the structure started to transform into Gyroid structure after annealing 14h and it took more than 2 days to accomplish the transition. Furthermore, it was also confirmed that Gyroid structure is oriented with its (110) normal to the film surface, the length of its repeating unit along with (110), 55nm, is similar to its original lamellar domain spacing, 58nm. [Copyright &y& Elsevier]

The morphology of a melt-quenched crystalline–crystalline diblock copolymer, poly(ε-caprolactone)-block-polyethylene (PCL-b-PE), was studied by small-angle X-ray scattering and transmission electron microscopy. The melting behavior of PCL-b-PE was also investigated by differential scanning calorimetry. The melting temperature of PCL blocks, Tm,PCL, was ca. 55°C and that of PE blocks was ca. 96°C. Therefore, the PE block always crystallized first during quenching from the microphase-separated melt into various temperatures Tc below Tm,PCL to yield an alternating structure composed of PE lamellae and amorphous layers (PE lamellar morphology), and subsequently the crystallization of PCL blocks started at Tc after some induction period. The PE lamellar morphology was preserved after the crystallization of PCL blocks at low crystallization temperatures (Tc<30°C), that is, the PCL block crystallized within the PE lamellar morphology. At high crystallization temperatures (45°C>Tc>30°C), on the other hand, the crystallization of PCL blocks destroyed the PE lamellar morphology to result in a new lamellar morphology mainly consisting of PCL lamellae and amorphous layers (PCL lamellar morphology). The PE crystals were fragmentarily dispersed in the PCL lamellar morphology. [Copyright &y& Elsevier]

We studied the phase separation of a polymer solution in thin slabs of thickness of micrometers. The material used was an asymmetrical binary system that consisted of 6 wt% semi-crystalline poly(ethylene butene) (or cEB) and 94 wt% of diisodecyl adipate (or DIDA) solvent. The de-mixing mechanism in the confined geometry is very different from that in bulk. Phase separation in bulk usually starts with formation of the solvent holes, and polymer-rich phase becomes a micro-reticulated network. While, in thin films the phase separation starts with formation of the polymer-rich droplets, that behave like Brownian particles. We have observed that there exists a critical thickness Lc below which the size of the droplets decreases drastically. Above the critical thickness, we have observed a phase morphological transformation from droplets to chains, branches, and then to networks, which follows a very similar pattern of a percolation process. There is correspondingly a second critical thickness Lc&ast; (>Lc) below which no bi-continuous phase separation takes place. [Copyright &y& Elsevier]

We report the morphological characterization of asymmetric miktoarm star block copolymers of the (PS- b -PI) n PS type where n =2,3 (denoted 2DB and 3DB miktoarm stars, respectively) and a symmetric super H-shaped block copolymer of the (PS- b -PI) 3 PS(PI- b -PS) 3 type (denoted SH) which were synthesized by anionic polymerization. The initial volume fraction of PS ( φ PS ) for each copolymer was 0.51–0.56, giving a lamellar morphology. Addition of homopolystyrene (hPS) with a molecular weight lower than the respective PS blocks in the neat materials lead to a transition from the lamellar structure to hexagonally packed cylinders. Addition of low molecular weight homopolyisoprene (hPI) on the other hand, only resulted in swollen lamellae even when the overall composition was highly asymmetric (80/20). Changes in the lamellar spacing as well as in the respective PS and PI layer thickness were measured by SAXS. The transition from lamellae to cylinders with increased PS content occurred without the observation of an intervening cubic morphology for the 2DB and 3DB miktoarm stars. However, blends with 30 and 35% hPS (( φ PS ) total =0.68–0.70) with the super H-shaped block copolymer lead to the observation of lamellar-catenoid structures. [ABSTRACT FROM AUTHOR]

Crystal morphologies are essential for deciphering the reaction history of igneous and metamorphic rocks because they often record the interplay between nucleation and growth rates controlled by the departure from equilibrium. Here, we report an exceptional record of the morphological transition of olivine formed during subduction metamorphism and high-pressure dehydration of antigorite-serpentinite to prograde chlorite-harzburgite in the Almirez ultramafic massif (Nevado–Filábride Complex, Betic Cordillera, SE Spain). In this massif, rare varied-textured chlorite-harzburgite (olivine+enstantite+chlorite+oxides) —formed after high–P dehydration of antigorite-serpentinite— exhibits large olivine porphyroblasts made up of rounded cores mantled by coronas of tabular olivine grains, similar to single tabular olivines occurring in the matrix. The correlative X-ray μ-CT and EBSD study of two varied-textured chlorite-harzburgite samples show that tabular olivine in coronas is tabular on (100) Ol with c > b >> a, and grew in nearly the same crystallographic orientation as the rounded olivine cores of the porphyroblast. Quantitative textural analysis and mass balance indicate that varied-textured chlorite-harzburgite is the result of a two-stage nucleation and growth of olivine during the progress of the high–P dehydration of antigorite-serpentinite to chlorite-harzburgite reaction. The first stage occurred under a low affinity (ΔG r) and affinity rate (ΔG r /dt) of the antigorite dehydration reaction that resulted in a low time-integrated nucleation rate and isotropic growth of olivine, forming rounded olivine porphyroblasts. With further progress of the dehydration reaction, a second stage of relatively higher affinity and affinity rate resulted in a higher time-integrated nucleation rate of olivine coeval with a shift from isotropic to anisotropic olivine growth, leading to tabular olivines. The two-stage evolution resulted in olivine porphyroblasts made up of rounded cores mantled by coronas of tabular olivine grains characteristic of varied-texture chlorite-harzburgite. Although a switch to anisotropic tabular olivine in the second stage is consistent with the relative increase in the affinity and affinity rate, these changes cannot solely account for the growth of Almirez olivine tabular on (100). Tabular olivines in komatiites and other igneous rocks are tabular on (010) Ol with either a > c >> b, or a ≈ c > > b, in agreement with experimentally determined growth rates of olivine phenocrysts under moderate to high undercooling and cooling rates. On the other hand, olivine tabular on (100) is expected in the presence of highly polymerized fluids where inhibited growth of the olivine (100) and (010) interfaces occurs, respectively, due to dissociative and molecular adsorption of water monolayers. Rounded and tabular olivines in Almirez varied-textured chlorite-harzburgite show differing trace element compositions that we interpret as due to the infiltration of external fluids during antigorite dehydration. Isothermal infiltration of highly polymerized fluids would explain the shift in the affinity and affinity rate of the antigorite dehydration reaction, as well as the olivine morphology tabular on (100) due to the inhibited growth on the (100) and, to a lesser extent, (010). Our study shows that surface-active molecules may play an essential role in shaping the morphology of growing crystals during fluid-present metamorphic crystallization. Unlabelled Image • Morphological transition of olivine during serpentinite dehydration to peridotite • Rounded olivine morphology records near-equilibrium slow crystallization • Tabular olivine morphology is a result of rapid growth at fast reaction kinetics. • Reported habit, tabular on (100) with c > b> > a, differs from common tabular olivine. • Surfactants in infiltrating fluids selectively inhibited growth on (100) and (010). [ABSTRACT FROM AUTHOR]

We conduct analogue experiments using starch and water mixture to understand the key factors controlling morphological transitions from colonnade to entablature of columnar joints. Columnar joints are formed by volume contraction during cooling. The isotherms are assumed to be perpendicular to the direction of the columns. However, observations of the morphological transition between colonnade and entablature and morphology in the entablature part are complex; it is expected that their formations are caused by a change in the distribution of the isotherms. Analogue experiments using starch and water mixtures have been conducted to reproduce the formation of colonnade (straight columns) but not for curved structures. We conduct experiments to reproduce the curved structures and investigate the process of crack propagation from two non-parallel drying surfaces and the relationship between the water distribution and crack development in the starch and water mixture by observing X-ray computed tomography (CT) images over time. In addition, the numbers of columns and cross-sectional areas are measured to interpret the column nucleation, which causes a decrease in the average column width. Based on analytical and numerical solutions of a simple diffusion equation, we examine the effect of critical temperature for crack initiation on curved structures, with a discussion comparing experimental results. The results and discussions suggest that 1) the curvature in crack development is likely controlled not only by the isotherm but also by the temperature at crack initiation and 2) an instantaneous increase in the cooling rate induces the column nucleation at the crack front. Finally, we propose a scenario of morphological transition from colonnade to entablature at Shakushiiwa, Aso-4 welded tuff, in Japan, which shows a threefold structure (upper colonnade – entablature – lower colonnade) based on our experimental results. We introduce two modes of heat transfers: vertical heat transfer Q d within intact rocks by thermal diffusion toward the upper cooling surface and horizontal heat transfer Q v through the cracks. The transition between the modes induces a drastic change in the shape of the isotherm at the crack front, resulting in the morphological transition from colonnade to entablature. • Analogue experiments for reproducing curved columnar joints are performed. • The curvature in crack development is controlled by the temperature for the formation of cracks. • Column nucleation occurs at the crack front by a sudden increase in cooling rate. • The morphological transition is caused by the drastic change of the thermal distribution at the crack front. [ABSTRACT FROM AUTHOR]

• Co-assembly of peptide AmpF with its two derivatives into nanomedicines with morphologies ultra-sensitive to medium pH. • Uptaking nanomedicines via an endo-/lysosome-mediated pathway renders their morphology adaptable to tissue/organelle pH. • The adaptable nanomedicines prolonged blood circulation and facilitated tumor penetration and accumulation. • The improved delivering efficiency led to enhanced combinatorial chemo-photodynamic therapy against breast tumors. The persistent morphology of conventional delivering systems limits their capability to further simultaneously optimize pharmokinetics and overcome the physiological delivering barriers. To address this challenge, here we report nanomedicines delivered by morphology-adaptable platforms for enhanced drug delivering and combinatorial chemo-photodynamic therapeutic efficacy. The nanomedicines were created by co-assembling a pentapeptide (AmpF) containing a 4-amino proline (Amp) with its two derivatives CPT-AmpF and IR820-AmpF, which are functionalized by drug camptothecin (CPT) and photosensitizer new indocyanine green IR820, respectively. The resulting nanomedicines formed superhelices and nanoparticles under neutral and mild acidic pH conditions. Cellular experiments revealed that the nanomedicines were up-taken by breast cancer cells via an endo-/lysosome-mediated mechanism, thus allowing the nanomedicines to undergo a reversible superhelice-nanoparticle morphological transition during the delivering pathway. Therefore, the superhelcial morphology of the nanomedicines prolonged blood circulation and tumor retention, whereas the transformed nanoparticles facilitated penetration and accumulation at tumor sites. Compared to the morphology-persistent counterparts, the improved delivering efficiency of the adaptable nanomedicines resulted in the enhanced combinatorial chemo-photodynamic therapy against breast tumors, thus potentially leading to a facile and versatile strategy for drug delivery and paving the way toward new-generation nanomedicines in the future. [ABSTRACT FROM AUTHOR]