Promoting Network Formation in Nanorod-filled Binary Blends

2012 ◽  
Vol 1411 ◽  
Author(s):  
Li-Tang Yan ◽  
Egor Maresov ◽  
Ryan C. Hayward ◽  
Todd Emrick ◽  
Thomas P. Russell ◽  
...  
Keyword(s):  
Network Formation ◽  
Early Stage ◽  
Continuous Phase ◽  
Domain Growth ◽  
Repulsive Interaction ◽  
Binary Blends ◽  
Growth Regime ◽  
The Matrix ◽  
Effective Attraction ◽  
Droplet Morphology

ABSTRACTUsing a hybrid computational approach, we introduce A-like nanorods into a phaseseparating AB blend, which has 45/55 composition. In the absence of the rods, the minority A phase forms droplets in the matrix of B. With the addition of N = 670 rods that interact solely through a short range repulsive interaction (mimicking the steric stabilization provided by a coating of A ligands), the mixture retains this droplet morphology. When, however, we add an effective attraction between the sterically stabilized rods, the nanoparticles form extensive networks in the A phase, which can form a continuous phase. In addition to altering the morphology of the mixture, the attractive interaction influences the rate of domain growth. In particular, at early times, the mutually attractive rods increase the growth rate of the domains in the early stage. At late times, the domain growth crosses over to a slow growth regime. Our findings demonstrate that the morphology and coarsening of a rod-filled blend can be controlled by varying the rod-rod interaction and hence, provides guidelines for tailoring the electrical and mechanical properties of the nanocomposites.

scholarly journals Exenatide Microspheres for Monthly Controlled-Release Aided by Magnesium Hydroxide

Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 816
Author(s):  
Yuxuan Ge ◽  
Zhenhua Hu ◽  
Jili Chen ◽  
Yujie Qin ◽  
Fei Wu ◽  
...  
Keyword(s):  
Controlled Release ◽  
Dosage Form ◽  
Continuous Phase ◽  
Plga Microspheres ◽  
Receptor Agonists ◽  
Monkey Model ◽  
The Matrix ◽  
Glass Membrane ◽  
The One ◽  
Long Acting

GLP-1 receptor agonists are a class of diabetes medicines offering self-regulating glycemic efficacy and may best be administrated in long-acting forms. Among GLP-1 receptor agonists, exenatide is the one requiring the least dose so that controlled-release poly(d, l-lactic-co-glycolic acid) (PLGA) microspheres may best achieve this purpose. Based on this consideration, the present study extended the injection interval of exenatide microspheres from one week of the current dosage form to four weeks by simply blending Mg(OH)2 powder within the matrix of PLGA microspheres. Mg(OH)2 served as the diffusion channel creator in the earlier stage of the controlled-release period and the decelerator of the self-catalyzed degradation of PLGA (by the formed lactic and glycolic acids) in the later stage due to its pH-responsive solubility. As a result, exenatide gradually diffused from the microspheres through Mg(OH)2-created diffusion channels before degradation of the PLGA matrix, followed by a mild release due to Mg(OH)2-buffered degradation of the polymer skeleton. In addition, an extruding–settling process comprising squeezing the PLGA solution through a porous glass membrane and sedimentation-aided solidification of the PLGA droplets was used to prepare the microspheres to ensure narrow size distribution and 95% encapsulation efficiency in an aqueous continuous phase. A pharmacokinetic study using rhesus monkey model confirmed the above formulation design by showing a steady blood concentration profile of exenatide with reduced CMAX and dosage form index. Mg·(OH)2

scholarly journals BslA-stabilized emulsion droplets with designed microstructure

2017 ◽  
Vol 7 (4) ◽  
pp. 20160124 ◽  
Author(s):  
Keith M. Bromley ◽  
Cait E. MacPhee
Keyword(s):  
Structural Integrity ◽  
Melting Process ◽  
Continuous Phase ◽  
Central Component ◽  
Emulsion Droplet ◽  
Emulsion Droplets ◽  
Elastic Film ◽  
Air Water Interface ◽  
Droplet Morphology ◽  
Spherical Droplets

Emulsions are a central component of many modern formulations in food, pharmaceuticals, agrichemicals and personal care products. The droplets in these formulations are limited to being spherical as a consequence of the interfacial tension between the dispersed phase and continuous phase. The ability to control emulsion droplet morphology and stabilize non-spherical droplets would enable the modification of emulsion properties such as stability, substrate binding, delivery rate and rheology. One way of controlling droplet microstructure is to apply an elastic film around the droplet to prevent it from relaxing into a sphere. We have previously shown that BslA, an interfacial protein produced by the bacterial genus Bacillus , forms an elastic film when exposed to an oil- or air–water interface. Here, we highlight BslA's ability to stabilize anisotropic emulsion droplets. First, we show that BslA is capable of arresting dynamic emulsification processes leading to emulsions with variable morphologies depending on the conditions and emulsification technique applied. We then show that frozen emulsion droplets can be manipulated to induce partial coalescence. The structure of the partially coalesced droplets is retained after melting, but only when there is sufficient free BslA in the continuous phase. That the fidelity of replication can be tuned by adjusting the amount of free BslA in solution suggests that freezing BslA-stabilized droplets disrupts the BslA film. Finally, we use BslA's ability to preserve emulsion droplet structural integrity throughout the melting process to design emulsion droplets with a chosen shape and size.

scholarly journals Squamous Cell Carcinoma in a Calyceal Diverticulum Detected by Percutaneous Nephroscopic Biopsy

2018 ◽  
Vol 2018 ◽  
pp. 1-4
Author(s):  
Taku Mitome ◽  
Tadashi Tabei ◽  
Yukio Tsuura ◽  
Kazuki Kobayashi
Keyword(s):  
Computed Tomography ◽  
Squamous Cell Carcinoma ◽  
Cell Carcinoma ◽  
Squamous Cell ◽  
Early Stage ◽  
High Grade ◽  
Curative Intent ◽  
The Matrix ◽  
Calyceal Diverticulum ◽  
Pathological Assessment

A 73-year-old woman was referred to our department with a complaint of asymptomatic gross hematuria. Dynamic computed tomography revealed a complicated (Bosniak type IIF) cyst in the upper pole of her right kidney, which was diagnosed as a calyceal diverticulum. The diagnosis was confirmed by ureteroscopy. The diverticulum was filled with a soft protein matrix that was difficult to completely remove from the inner surface of the calyceal diverticulum. Endoscopy combined with intrarenal surgery (ECIRS) was performed to completely remove the matrix. Percutaneous nephroscopy further revealed papillary lesions on the surface of the diverticulum, confirmed as squamous cell carcinoma on pathological assessment. A laparoscopic right radical nephroureterectomy was performed, with curative intent. Pathological assessment confirmed a high-grade squamous cell carcinoma with renal parenchymal invasion (pT3). Although carcinomas in a calyceal diverticulum are highly uncommon, when present, these tend to be high-grade neoplasms that deeply invade the parenchymal wall. As the effective management of these lesions is difficult, early-stage diagnosis is required for curative treatment. We report the case of squamous cell carcinoma in a calyceal diverticulum that was difficult to diagnose on preoperative computed tomography, urinal cytology examination, and ureteroscopy but was found during ECIRS.

scholarly journals Peroxisomal assembly: membrane proliferation precedes the induction of the abundant matrix proteins in the methylotrophic yeast Candida boidinii

1990 ◽  
Vol 96 (4) ◽  
pp. 583-590
Author(s):  
M. Veenhuis ◽  
J.M. Goodman
Keyword(s):  
Early Stage ◽  
Morphological Changes ◽  
Polyclonal Antibodies ◽  
Alcohol Oxidase ◽  
Methylotrophic Yeast ◽  
Candida Boidinii ◽  
Peroxisomal Membrane ◽  
Cell Induction ◽  
The Matrix ◽  
Dihydroxyacetone Synthase

Peroxisomes are massively induced when methylotrophic yeasts are cultured in medium containing methanol. These organelles contain enzymes that catalyze the initial steps of methanol assimilation. In Candida boidinii, a methylotrophic yeast, the peroxisomal matrix (internal compartment) is composed almost exclusively of two proteins, alcohol oxidase and dihydroxyacetone synthase; catalase is present in much lower abundance. Monoclonal and polyclonal antibodies are available against peroxisomal matrix and membrane proteins. These were utilized to correlate the induction of specific proteins with the morphological changes occurring during peroxisomal proliferation. Cells cultured in glucose-containing medium contain two to five small microbodies, which are identifiable by catalase staining and immunoreactivity with a monoclonal antibody against PMP47, an integral peroxisomal membrane protein. Three stages of proliferation can be distinguished when cells are switched to methanol as the carbon source. (1) There is an early stage (within 1 h) in which several peroxisomes develop from a preexisting organelle. This is accompanied by an increase in catalase activity and an induction of PMP47, but no detectable induction of alcohol oxidase or dihydroxyacetone synthase is observed. (2) From 1 to 2.5 h there is further division of these microbodies until up to 30 small peroxisomes generally are present in each of one or two clusters per cell. Induction of alcohol oxidase, dihydroxyacetone synthase and PMP20, a protein that is distributed in the matrix and membrane, is detectable during this time. Serial sections reveal that some peroxisomes remain uninduced while others undergo proliferation. Such sections also show no obvious connections between peroxisomes within clusters.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals INFLUENZA INFLAMMATION BIOMARKERS FEATURES

2019 ◽  
Vol 1 (3) ◽  
pp. 67-73
Author(s):  
T. P. Ospelnikova ◽  
O. V. Morozova ◽  
S. A. Andreeva ◽  
E. I. Isaeva ◽  
L. V. Kolodyazhnaya ◽  
...  
Keyword(s):  
Gene Expression ◽  
Immune Response ◽  
Influenza Virus ◽  
Magnetic Beads ◽  
Early Stage ◽  
Influenza Infection ◽  
Rt Pcr ◽  
The Matrix ◽  
Polarization Coefficient ◽  
Th1 Immune Response

Aim. Analysis of inflammation biomarkers using reverse transcription with real time PCR (RT-PCR-RT) and multiplex immunofluorescent analysis xMAP with magnetic beads for the influenza infection. Materials and methods. Analysis of nasopharyngeal swabs, lymphocytes and blood sera of 10 patients with influenza and 10 donors was performed during the first 2 days of the disease by means of RT-PCR-RT and xMAP using the kit «37-plex» (BioRad). Results.The influenza virus A was revealed in 4 samples, the influenza virus B — in 6 swabs without mixed infections with other respiratory viruses. Analysis of the interferons (IFN) showed IFNα gene expression activation in patients’ lymphocytes but both the detection rate and the concentrations of IFNβ, IFNγ and IFNλ RNA were similar for patients and healthy donors. Among 37 inflammation biomarkers the concentrations of 7 proteins were enhanced including IFNα2, cytokines of TNF family (APRIL and BAFF), their soluble receptors sTNF-R1 and sTNF-R2, protein osteopontin and IL10. The concentrations of the complex of glycoprotein gp130 with the soluble receptor IL6 gp130/sIL-6Rβ and the matrix metalloprotease ММР-1 were reduced in patients’ sera. The polarization coefficient PI=[IL10]/[IFNγ]=0.53 for influenza samples suggested Th1 immune response. Conclusion. At the early stage of the influenza infection IFNα gene expression activation along with the induction of TNF family cytokines (APRIL and BAFF), their receptors (sTNF-R1 and sTNF-R2) and osteopontin as well as the inhibition of the complex gp130/sIL-6Rβ and metalloprotease ММР-1 were shown. Th1 immune response regulated by IL10 resulted in the recovery of the patients without complications.

Euclidean path integrals and quantum mechanics (QM)

2021 ◽  
pp. 18-41
Author(s):  
Jean Zinn-Justin
Keyword(s):  
Quantum Mechanics ◽  
Path Integral ◽  
Correlation Functions ◽  
Path Integrals ◽  
Continuous Phase ◽  
Functional Integral ◽  
Smooth Transition ◽  
Path Integral Representation ◽  
The Matrix ◽  
Functional Measure

Functional integrals are basic tools to study first quantum mechanics (QM), and quantum field theory (QFT). The path integral formulation of QM is well suited to the study of systems with an arbitrary number of degrees of freedom. It makes a smooth transition between nonrelativistic QM and QFT possible. The Euclidean functional integral also emphasizes the deep connection between QFT and the statistical physics of systems with short-range interactions near a continuous phase transition. The path integral representation of the matrix elements of the quantum statistical operator e-β H for Hamiltonians of the simple separable form p2/2m +V(q) is derived. To the path integral corresponds a functional measure and expectation values called correlation functions, which are generalized moments, and related to quantum observables, after an analytic continuation in time. The path integral corresponding to the Euclidean action of a harmonic oscillator, to which is added a time-dependent external force, is calculated explicitly. The result is used to generate Gaussian correlation functions and also to reduce the evaluation of path integrals to perturbation theory. The path integral also provides a convenient tool to derive semi-classical approximations.

scholarly journals Hypoxia and matrix viscoelasticity sequentially regulate endothelial progenitor cluster-based vasculogenesis

2019 ◽  
Vol 5 (3) ◽  
pp. eaau7518 ◽  
Author(s):  
Michael R. Blatchley ◽  
Franklyn Hall ◽  
Songnan Wang ◽  
Hawley C. Pruitt ◽  
Sharon Gerecht
Keyword(s):  
Reactive Oxygen Species ◽  
Extracellular Matrix ◽  
Network Formation ◽  
Underlying Mechanism ◽  
Oxygen Species ◽  
Endothelial Progenitor ◽  
Vascular Morphogenesis ◽  
The Matrix ◽  
Surrounding Extracellular Matrix

Vascular morphogenesis is the formation of endothelial lumenized networks. Cluster-based vasculogenesis of endothelial progenitor cells (EPCs) has been observed in animal models, but the underlying mechanism is unknown. Here, using O2-controllabe hydrogels, we unveil the mechanism by which hypoxia, co-jointly with matrix viscoelasticity, induces EPC vasculogenesis. When EPCs are subjected to a 3D hypoxic gradient ranging from <2 to 5%, they rapidly produce reactive oxygen species that up-regulate proteases, most notably MMP-1, which degrade the surrounding extracellular matrix. EPC clusters form and expand as the matrix degrades. Cell-cell interactions, including those mediated by VE-cadherin, integrin-β2, and ICAM-1, stabilize the clusters. Subsequently, EPC sprouting into the stiffer, intact matrix leads to vascular network formation. In vivo examination further corroborated hypoxia-driven clustering of EPCs. Overall, this is the first description of how hypoxia mediates cluster-based vasculogenesis, advancing our understanding toward regulating vascular development as well as postnatal vasculogenesis in regeneration and tumorigenesis.

Temperature-Related Ultrastructural Changes in Early Stage Amelogenesis in Vascularly Perfused Rat Incisors

1987 ◽  
Vol 1 (2) ◽  
pp. 371-379 ◽  
Author(s):  
Y. Takano ◽  
M. Akai ◽  
S. Matsuo ◽  
S. Wakisaka ◽  
H. Ichikawa ◽  
...  
Keyword(s):  
Granular Material ◽  
Matrix Protein ◽  
Early Stage ◽  
Physiological Solution ◽  
Ultrastructural Changes ◽  
Vascular Perfusion ◽  
Coated Pits ◽  
The Matrix ◽  
Perfusion Fixation ◽  
Definition Of

Vascularly perfused rat incisors were investigated by electron microscopy in order to achieve further definition of the origin and nature of stippled material in developing enamel. A prolonged (20-minute) pre-wash perfusion of the rat with a physiological solution at 37°C prior to perfusion fixation retained good morphology of the secretory ameloblasts and adjacent enamel, showing virtually no extracellular accumulation of granular material. Granular material appeared throughout the developing enamel after pre-wash perfusion at low temperatures (0-2°C), and accumulated in the extensively dilated extracellular spaces between the proximal portions of Tomes' processes, where numerous coated pits and coated vesicles were located. Vascular perfusion at 37°C, preceded by a cold perfusion, abolished the granular material in the developing enamel, whereas the granular material in the extracellular spaces between Tomes' processes remained as huge droplets of dense material. These results indicate that at least a part of the matrix protein of rat incisor developing enamel has the physico-chemical property to dissociate at low temperature during pre-wash perfusion and move toward the enamel surface. Thus, in perfusion-fixed specimens, an intimate relationship between the artifactual formation of stippled material and the temperature of the pre-wash perfusate is suggested.

A giant pterosaur from the Lower Cretaceous of the eastern Paris Basin

2004 ◽  
Vol 175 (6) ◽  
pp. 573-577 ◽  
Author(s):  
Eric Buffetaut
Keyword(s):  
Natural History ◽  
Lower Cretaceous ◽  
Early Stage ◽  
Natural History Museum ◽  
Paris Basin ◽  
History Museum ◽  
Geographical Data ◽  
Wing Span ◽  
The Matrix

Abstract A large pterosaur bone, preserved as a natural cast of the interior cavity, was found in an old collection kept at the Natural History Museum of Troyes (France). Although no precise geographical data are available, the lithology of the matrix indicates that it comes from the Hauterivian Toxaster Limestone of the eastern Paris Basin. Despite its unusual preservation, the specimen shows various morphological details, and is identified as an ornithocheiroid pterosaur humerus. This specimen is among the largest known pterosaur humeri (length as preserved: 345 mm), indicating a wing span of more than 7 metres. It shows that giant pterosaurs had already appeared at a very early stage in the Cretaceous.

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