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Journal articles on the topic 'Microphases. eng'

Author: Grafiati
Published: 4 June 2021
Last updated: 10 February 2022

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1

Zhang, Tao, Guangtao Chang, and Qipeng Guo. "Thermoreversible Polymer Gels in DMF Formed from Charge- and Crystallization-Induced Assembly." Polymers 12, no. 9 (September 10, 2020): 2056. http://dx.doi.org/10.3390/polym12092056.

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Polymer organogels formed through dynamic interactions are interesting for various applications. The fabrication of polymer organogels in polar solvents through ionic interaction is rare, although such organogels in non-polar organic solvents have been well studied. Herein, polymer organogels in a polar solvent N,N-dimethyl formamide (DMF) were fabricated from a triblock copolymer, poly(4-vinyl pyridine)-block-poly(ethylene glycol)-block-poly(4-vinyl pyridine) (4VPm-EGn-4VPm), and a fluorinated surfactant, perfluorooctanoic acid (PFOA), and their microphase separation and properties were studied. Ordered microphase separation and the crystalline structures were revealed by small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS), respectively. All the 4VPm-EGn-4VPm/PFOA organogels are sensitive to temperature, and the ratio of PFOA to pyridine groups reversibly. The polymer organogels are also responsive to triethylamine and triethylammonium acetate.
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German, Ian, Franck D’Agosto, Christophe Boisson, Sylvie Tencé-Girault, and Corinne Soulié-Ziakovic. "Microphase Separation and Crystallization in H-Bonding End-Functionalized Polyethylenes." Macromolecules 48, no. 10 (May 7, 2015): 3257–68. http://dx.doi.org/10.1021/ma502304k.

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3

Masamoto, J. "Microphase separation in polyoxymethylene end-capped with a long-chain alkyl." Polymer 41, no. 19 (September 2000): 7283–87. http://dx.doi.org/10.1016/s0032-3861(00)00075-6.

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4

Gavrilov, Alexey A., and Alexander V. Chertovich. "Polymerization-Induced Microphase Separation with Long-Range Order in Melts of Gradient Copolymers." Polymers 12, no. 11 (November 10, 2020): 2637. http://dx.doi.org/10.3390/polym12112637.

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In this work, we studied the question of whether it is possible to develop a one-step approach for the creation of microphase-separated materials with long-range order with the help of spontaneous gradient copolymers, i.e., formed during controlled copolymerization solely due to the large difference in the reactivity ratios. To that end, we studied the polymerization-induced microphase separation in bulk on the example of a monomer pair with realistic parameters based on styrene (S) and vinylpirrolydone (VP) by means of computer simulation. We showed that for experimentally reasonable chain lengths, the structures with long-range order start to appear at the conversion degree as low as 76%; a full phase diagram in coordinates (fraction of VP—conversion degree) was constructed. Rather rich phase behavior was obtained; moreover, at some VP fractions, order–order transitions were observed. Finally, we studied how the conversion degree at which the order–disorder transition occurs changes upon varying the maximum average chain length in the system.
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McLeod, Kelly R., and Gregory N. Tew. "Microphase-Separated Thiol–Ene Conetworks from Telechelic Macromonomers with Asymmetric Molecular Weights." Macromolecules 50, no. 20 (October 9, 2017): 8042–47. http://dx.doi.org/10.1021/acs.macromol.7b01681.

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6

Nikishau, Pavel A., Evgenii A. Ksendzov, Dmitriy I. Shiman, Ludmila V. Gaponik, and Sergei V. Kostjuk. "Synthesis of functionalized polyisobutylene and its block copolymers with D,L-lactide." Journal of the Belarusian State University. Chemistry, no. 2 (August 30, 2019): 40–50. http://dx.doi.org/10.33581/2520-257x-2019-2-40-50.

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Method of reactive polyisobutylene modification by various alkoxybenzenes (anisole and 4-phenoxybutanol) was proposed to form functionalized polyisobutylenes. Polymerization of D,L-lactide was explored on the 4-phenoxybutanol/1,5,7-triazabicyclo[4.4.0]dec-5-ene system. It led to determination of optimal conditions for gaining of poly(isobutylene-b-D,L-lactide). Such copolymers (Mn = 14 300 g/mol and Mn = 36 600 g/mol, Mw / Mn ≤ 2.5) which were obtained by the polymerization of D,L-lactide on polyisobutylene macroinitiator shows microphase ordering. Formation of the block copolymers is confirmed by 1Н NMR spectroscopy, gel permeation chromatography, and scanning electron microscopy.
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7

Choi, Taeyi, Jadwiga Weksler, Ajay Padsalgikar, Rebeca Hernéndez, and James Runt. "Polydimethylsiloxane-Based Polyurethanes: Phase-Separated Morphology and In Vitro Oxidative Biostability." Australian Journal of Chemistry 62, no. 8 (2009): 794. http://dx.doi.org/10.1071/ch09096.

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Three series of segmented polyurethane block copolymers were synthesized using 4,4′-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BDO) or 1,3-bis(4-hydroxybutyl)tetramethyl disiloxane (BHTD) as the hard segments, and soft segments composed of poly(dimethyl siloxane) (PDMS)-based and poly(hexamethylene oxide) (PHMO) macrodiols. Copolymers synthesized with the PDMS macrodiol and PDMS and PHMO macrodiol mixtures consist of three microphases: a PDMS phase, hard domains, and a mixed phase of PHMO (when present), PDMS ether end-group segments and some dissolved hard segments. Degrees of phase separation were characterized using small-angle X-ray scattering by applying a pseudo two-phase model, and the morphology resulting from unlike segment demixing was found to be closely related to the in vitro oxidative biostability of these segmented polyurethanes.
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8

Chao, Ying-Chieh, Jhe-Han Chen, Yi-Jie Chiou, Po-lin Kao, Jhao-Lin Wu, Chin-Ti Chen, Li-Hsin Chan, and Ru-Jong Jeng. "Design of Thienothiophene-Based Copolymers with Various Side Chain-End Groups for Efficient Polymer Solar Cells." Polymers 12, no. 12 (December 11, 2020): 2964. http://dx.doi.org/10.3390/polym12122964.

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Three two-dimensional donor–acceptor conjugated copolymers consisting of a benzo[1,2-b:4,5-b′]dithiophene derivative and thieno[3,2-b]thiophene with a conjugated side chain were designed and synthesized for use in bulk heterojunction (BHJ) or nonfullerene polymer solar cells (PSCs). Through attaching various acceptor end groups to the conjugated side chain on the thieno[3,2-b]thiophene moiety, the electronic, photophysical, and morphological properties of these copolymers were significantly affected. It was found that the intermolecular charge transfer interactions were enhanced with the increase in the acceptor strength on the thieno[3,2-b]thiophene moiety. Moreover, a better microphase separation was obtained in the copolymer: PC71BM or ITIC blend films when a strong acceptor end group on the thieno[3,2-b]thiophene moiety was used. As a result, BHJ PSCs based on copolymer:PC71BM blend films as active layers exhibited power conversion efficiencies from 2.82% to 4.41%, while those of nonfullerene copolymer:ITIC-based inverted PSCs ranged from 6.09% to 7.25%. These results indicate the side-chain engineering on the end groups of thieno[3,2-b]thiophene unit through a vinyl bridge linkage is an effective way to adjust the photophysical properties of polymers and morphology of blend films, and also have a significant influence on devices performance.
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9

Russell, T. P., V. R. Deline, V. S. Wakharkar, and G. Coulon. "Behavior of Block Copolymers in Thin Films." MRS Bulletin 14, no. 10 (October 1989): 33–37. http://dx.doi.org/10.1557/s0883769400061479.

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The uses of polymeric materials in today's world are vast. Polymers are finding applications in the microelectronics industry as dielectric insulators and photoresists, in the aerospace and automobile industry as lightweight substitutes for metals, and in biotechnology as replacement components for bone, heart, and other organs. These are just a few of the many end uses of polymers.Often, a polymer may have a particular, desirable property but processing of the polymer is difficult or the polymer's surface characteristics are undesirable. To circumvent such shortcomings there are several options. The first is to synthesize a new material, which is quite costly and time consuming. Alternatively, two polymers with complimentary properties can be mixed. Unfortunately, most polymer pairs are immiscible unless there are specific interactions (e.g., hydrogen bonding) between the two components. Consequently, coarse phase separation is often observed, leading to an ill-defined material. Finally, two chemically distinct homopolymers can be joined together at one point, forming a block copolymer. While phase separation may occur, the scale of the domains is restricted to the sizes of the individual homopolymers, which is typically on the tens of nanometers scale. The added advantage of this approach is that the size of the different blocks can be altered, varying the concentration of the different components. For copolymers that “microphase” separate, this variation in composition leads to a variation of the morphology of the microdomains ranging from spherical to cylindrical to lamellar.
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10

Spontak, R. J. "Direct casting of SBS block copolymers on supported grids for TEM study." Proceedings, annual meeting, Electron Microscopy Society of America 44 (August 1986): 788–89. http://dx.doi.org/10.1017/s0424820100145285.

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Transmission electron microscopy (TEM) has been used successfully in studying the microstructures resulting from microphase-separated block copolymers consisting of polystyrene (S) and polybutadiene (B). Difficulty, however, arises in the sample preparation stage, in which specimens ranging 50-100 nm thick are required. Such specimens can be obtained by either cutting ultrathin sections from a bulk sample or by dissolving the polymer in a suitable solvent and casting the solution to form an ultrathin film. Many methods exist for preparing such films, and almost all share one common feature: the cast film is floated on a clean fluid (e.g., water) surface. In some cases, the film is first cast on a carboncoated glass slide and scored prior to the flotation step so that small sections may be picked up by TEM grids. To avoid (a) casting the copolymer onto a flotation medium, which may inadvertently affect the microstructure orientation, (b) excessive handling of the cast film, and (c) exposing a hygroscopic copolymer (e.g., siloxane polyimide polymers) to a water surface, a method of casting copolymer films directly onto supported TEM grids is presented here.
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11

Sekine, Ryojun, Hiroyuki Aoki, and Shinzaburo Ito. "Chain End Distribution of Block Copolymer in Two-Dimensional Microphase-Separated Structure Studied by Scanning Near-Field Optical Microscopy." Journal of Physical Chemistry B 113, no. 39 (October 2009): 12865–69. http://dx.doi.org/10.1021/jp903227y.

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12

Yoshida, Kohei, Shunma Tanaka, Takuya Yamamoto, Kenji Tajima, Redouane Borsali, Takuya Isono, and Toshifumi Satoh. "Chain-End Functionalization with a Saccharide for 10 nm Microphase Separation: “Classical” PS-b-PMMA versus PS-b-PMMA-Saccharide." Macromolecules 51, no. 21 (October 30, 2018): 8870–77. http://dx.doi.org/10.1021/acs.macromol.8b02069.

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13

Lee, Kyu Seong, Philgon Kim, Jaeyong Lee, Chungryong Choi, Yeseong Seo, So Yeong Park, Keonwoo Kim, et al. "End-on Chain Orientation of Poly(3-alkylthiophene)s on a Substrate by Microphase Separation of Lamellar Forming Amphiphilic Diblock Copolymer." Macromolecules 52, no. 17 (August 28, 2019): 6734–40. http://dx.doi.org/10.1021/acs.macromol.9b01266.

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14

Hermida-Merino, Daniel, Gemma E. Newby, Ian W. Hamley, Wayne Hayes, and Andrew Slark. "Microphase separation induced in the melt of Pluronic copolymers by blending with a hydrogen bonding urea–urethane end-capped supramolecular polymer." Soft Matter 11, no. 29 (2015): 5799–803. http://dx.doi.org/10.1039/c5sm01461a.

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15

Garces, Irina, Samira Aslanzadeh, Yaman Boluk, and Cagri Ayranci. "Effect of Moisture on Shape Memory Polyurethane Polymers for Extrusion-Based Additive Manufacturing." Materials 12, no. 2 (January 12, 2019): 244. http://dx.doi.org/10.3390/ma12020244.

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Extrusion-based additive manufacturing (EBAM) or 3D printing is used to produce customized prototyped parts. The majority of the polymers used with EBAM show moisture sensitivity. However, moisture effects become more pronounced in polymers used for critical applications, such as biomedical stents, sensors, and actuators. The effects of moisture on the manufacturing process and the long-term performance of Shape Memory Polyurethane (SMPU) have not been fully investigated in the literature. This study focuses primarily on block-copolymer SMPUs that have two different hard/soft (h/s) segment ratios. It investigates the effect of moisture on the various properties via studying: (i) the effect of moisture trapping within these polymers and the consequences when manufacturing; (ii) and the effect on end product performance of plasticization by moisture. Results indicate that higher h/s SMPU shows higher microphase separation, which leads to an increase of moisture trapping within the polymer. Understanding moisture trapping is critical for EBAM parts due to an increase in void content and a decrease in printing quality. The results also indicate a stronger plasticizing effect on polymers with lower h/s ratio but with a more forgiving printing behavior compared to the higher h/s ratio.
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16

Natori, Itaru, Shizue Natori, Anna Kanasashi, Kosuke Tsuchiya, and Kenji Ogino. "Thin film of a porphyrin-end-functionalized poly(cyclohexane)/fullerene-end-functionalized poly(4-diphenylaminostyrene) blend: Control of microphase separation in a light-harvesting system for polymer solar cells." Journal of Applied Polymer Science 128, no. 6 (October 18, 2012): 4212–16. http://dx.doi.org/10.1002/app.38647.

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17

Merino, Daniel Hermida, Antonio Feula, Kelly Melia, Andrew T. Slark, Ioannis Giannakopoulos, Clive R. Siviour, C. Paul Buckley, et al. "A systematic study of the effect of the hard end-group composition on the microphase separation, thermal and mechanical properties of supramolecular polyurethanes." Polymer 107 (December 2016): 368–78. http://dx.doi.org/10.1016/j.polymer.2016.07.029.

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18

Wlasow, Teresa, and Dorota Fopp-Bayat. "The effect of thermal shock on morphological characteristics of blood cells in Siberian sturgeon (Acipenser baerii) triploids." Acta Veterinaria Brno 80, no. 2 (2011): 215–18. http://dx.doi.org/10.2754/avb201180020215.

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The aim of the study was to evaluate the effect of thermal shock on morphotic blood elements in Siberian sturgeonAcipenser baeriitriploids. The thermal shock (37 °C for 2 min) was applied in the 18thmin after fertilization. Blood was sampled from parallel cultured ten triploids and ten diploids on day 70 after hatching. Ploidy was assessed with the cytogenetic method and measurements of cellular nuclei. In the blood of triploids, significant dominance of immature red blood cells, erythrocytes with a displaced nucleus, microcytes and erythroplastids were observed. The blood of triploids was also characterized by a reduced number of lymphocytes. The percentage of neutrophil and eosinophil granulocytes was elevated; increased share of neutrophil granulocytes with a 4-, 5- or 6-segmented nucleus and eosinophil granulocytes with a nucleus consisting of three and more segments was observed. Disturbances in the picture of red blood cells can be considered as an expression of intensification of end-stage changes in triploids. The response to these changes in the blood of triploid Siberian sturgeon is an increase in the share of polymorphonuclear PMN, cells counted as microphages. Frequent presence of immature red blood cells in triploid Siberian sturgeon is a process that aims at counterbalancing the loss among these blood cells. It is the first report on morphological changes and proportions among blood cells in triploid Siberian sturgeon.
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Gui, Qilin, Qi Ouyang, Chunrong Xu, Hongxue Ding, Shuxian Shi, and Xiaonong Chen. "Facile and Safe Synthesis of Novel Self-Pored Amine-Functionalized Polystyrene with Nanoscale Bicontinuous Morphology." International Journal of Molecular Sciences 21, no. 24 (December 10, 2020): 9404. http://dx.doi.org/10.3390/ijms21249404.

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The chloromethyl-functionalized polystyrene is the most commonly used ammonium cation precursor for making anion exchange resins (AER) and membranes (AEM). However, the chloromethylation of polystyrene or styrene involves highly toxic and carcinogenic raw materials (e.g., chloromethyl ether) and the resultant ammonium cation structural motif is not stable enough in alkaline media. Herein, we present a novel self-pored amine-functionalized polystyrene, which may provide a safe, convenient, and green process to make polystyrene-based AER and AEM. It is realized by hydrolysis of the copolymer obtained via random copolymerization of N-vinylformamide (NVF) with styrene (St). The composition and structure of the NVF-St copolymer could be controlled by monomeric ratio, and the copolymers with high NVF content could form bicontinuous morphology at sub-100 nm levels. Such bicontinuous morphology allows the copolymers to be swollen in water and self-pored by freeze-drying, yielding a large specific surface area. Thus, the copolymer exhibits high adsorption capacity (226 mg/g for bisphenol A). Further, the amine-functionalized polystyrene has all-carbon backbone and hydrophilic/hydrophobic microphase separation morphology. It can be quaternized to produce ammonium cations and would be an excellent precursor for making AEM and AER with good alkaline stability and smooth ion transport channels. Therefore, the present strategy may open a new pathway to develop porous alkaline stable AER and AEM without using metal catalysts, organic pore-forming agents, and carcinogenic raw materials.
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UMEDA, Hideo, Shinichi SAKURAI, Yuichi KITAGAWA, Yoshikazu SUDA, Junzo MASAMOTO, and Shunji NOMURA. "Engineering Plastics-Recent Developments in Synthesis and Applications. Changes in Morphology and Mechanical Properties with Composition for Microphase-Separated Polystyrene-block-Poly(ethylene-co-but-1-ene)-block-Polystyrene Triblock Copolymers." KOBUNSHI RONBUNSHU 54, no. 4 (1997): 236–43. http://dx.doi.org/10.1295/koron.54.236.

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21

Natori, Itaru, Shizue Natori, Anna Kanasashi, Kosuke Tsuchiya, and Kenji Ogino. "Formation of a porphyrin/fullerene light-harvesting system from self-assembly of porphyrin-end-functionalized polycyclohexane and [6,6]-phenyl-C61-butyric acid methyl ester: Effects of microphase separation and π-π interactions." Journal of Polymer Science Part B: Polymer Physics 51, no. 5 (November 27, 2012): 368–75. http://dx.doi.org/10.1002/polb.23222.

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22

Zhelavskyi, M. M., and O. Ya Dmytriv. "Immunobiological status of the body of cows during mastitis." Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies 20, no. 88 (August 25, 2018): 3–10. http://dx.doi.org/10.32718/nvlvet8801.

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The work reveals the immunobiological aspects of lactation of cows and changes in immunobiological reactivity in the development of mastitis.The authors present modern scientific data on the local immune protection of the mammary gland of cows. Main stages of ontogenetic development of cellular immunity of the mammary gland of cows were traced during clinical and experimental studies. The number of somatic cells in the secret of the mammary gland of the primates was dependent on the period of the functioning of the mammary gland. In the cytology of colostrum mostly (56.00 ± 1.90%) neutrophil granulocytes were predominant, in the middle period of lactation (3–5th month) the proportion of epithelial cells increased (from 29.51 ± 2.17 to 49.59 ± 1.94%), during the launch period, the population of polymorphonuclear neutrophil granulocytes was changing as well, which virtually recovered to the original level and increased during the dry period. However, at the end of lactation, during the onset and dry, with the development of involutionary processes in the mammary gland, a sharp decrease in cytochemical reactivity of intracellular lysozyme of phagocytic cells was observed. To conduct clinical and experimental studies, three groups of animals were formed. As a result, it was found out that subclinical mastitis of cows is accompanied by a change in the immunobiological reactivity. Purulent-catarrhal mastitis in cows was manifested by significant changes in the parameters of nonspecific immunological reactivity. In the peripheral blood of cows with subclinical mastitis, the number of reactive microphages increased sharply (P < 0.001). In parallel with this, the number of activated phagocytes with myeloperoxidase granules also increased in the peripheral blood (P < 0.01). Activation of intra-leukocyte lysozyme phagocytic cells was less intensive. Subclinical udder pathology was accompanied by an increase in the number of degranulated cells (P < 0.001), which is one of the specific properties of cytomorphological changes in programmed death (apoptosis). Subclinical inflammation of the mammary glands mastitis of cows was accompanied by a certain decrease in the number of T-lymphocytes (P < 0.001). Clinical and experimental studies have shown that subclinical and purulent-catarrhal mastitis of cows undergo significant changes in systemic immunity. In the pathophysiological model of subclinical and purulent-catarrhal mastitis, the functional state of the T-link of specific immunity was disturbed, the bactericidal activity of blood serum and phagocytosis were suppressed, which occurred against the background of changes in the cytochemical reactivity of phagocytic cells circulating immune complexes and molecules with an average molecular weigh.
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23

Rao, A. V. "Lycopene, Tomatoes, and the Prevention of Coronary Heart Disease." Experimental Biology and Medicine 227, no. 10 (November 2002): 908–13. http://dx.doi.org/10.1177/153537020222701011.

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Coronary heart disease (CHD) is one of the primary causes of death in the Western world. The emphasis so far has been on the relationship between serum cholesterol levels and the risk of CHD. More recently, oxidative stress induced by reactive oxygen species (ROS) is also considered to play an important part in the etiology of this disease. Oxidation of the circulating low-density lipoprotein (LDLox) is thought to play a key role in the pathogenesis of atherosclerosis and CHD. According to this hypothesis, macrophages inside the arterial wall take up the LDLox and initiate the process of plaque formation. Dietary antioxidants such as vitamin E and ß-carotene have been shown in In vitro studies to prevent the formation of LDLox and their uptake by microphages. In a recent study, healthy human subjects ingesting lycopene, a carotenoid antioxidant, in the form of tomato juice, tomato sauce, and oleoresin soft gel capsules for 1 week had significantly lower levels of LDLox compared with controls. The antioxidant effects of lycopene have also been shown in four other human trials, including one where lycopene consumption reduced the levels of breath pentane. However, in one recent study, dietary supplementation with ß-carotene but not with lycopene was shown to inhibit LDL oxidation. The sources of lycopene used in most of these studies were either tomato products or lycopene extracted from tomatoes containing other carotenoids in various proportions. Therefore, it is not possible to attribute the effects solely to lycopene. Mechanisms other than the antioxidant properties of lycopene have also been shown to reduce the risk of CHD. Lycopene was shown to inhibit the activity of an essential enzyme involved in cholesterol synthesis in an in vitro and a small clinical study suggesting a hypocholesterolemic effect. Other possible mechanisms include enhanced LDL degradation, LDL particle size and composition, plaque rupture, and altered endothelial functions. Recent epidemiological studies have also shown an inverse relationship between tissue and serum levels of lycopene and mortality from CHD, cerebrovascular disease, and myocardial infraction. However, the most impressive population-based evidence comes from a multicenter case-control study where subjects from 10 European countries were evaluated for relationship between antioxidant status and acute myocardial infarctions. After adjusting for a range of dietary variables, only lycopene levels but not ß-carotene were found to be protective. At present, the role of lycopene in the prevention of CHD is strongly suggestive. Although the antioxidant property of lycopene may be one of the principal mechanism for its effect, other mechanisms may also be responsible. Controlled clinical and dietary intervention studies using well-defined subject populations and disease end points must be undertaken in the future to provide definitive evidence for the role of lycopene in the prevention of CHD. Mechanistic studies must also be initiated to understand the mode of lycopene action.
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Zhang, Rui, Vincent Degos, Shuai Kang, Michael Wong, Lei Zhan, and Hua Su. "Abstract 191: Persistent Infiltration of Active Microglia in Brain Arteriovenous Malformation Causes Unresolved Inflammation and Lesion Progression." Stroke 46, suppl_1 (February 2015). http://dx.doi.org/10.1161/str.46.suppl_1.191.

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Background and Purpose: Monocytes are present in human brain arteriovenous malformation (bAVM), but their roles and origin are not clear. Endoglin (Eng, a bAVM causative gene) mutation extends CD68+ cell retention in the mouse stroke brain. Using 2 mouse bAVM models, we tested the hypothesis that CD68+ cells in bAVM are mostly active microglia, which cause unresolved inflammation and lesion progression. Methods: In Model 1, using Rosa-CreER;Eng-floxed mice, AVM was induced through global Eng deletion, and brain focal angiogenesis stimulated by an adeno-associated viral vector expressing vascular endothelial growth factor (AAV-VEGF). In Model 2, using CCR2RFP/+/CX3CR1GFP/+;Alk1 (another bAVM causative gene) floxed mice, AVM was induced through focal Alk1 deletion, and angiogenesis by intra-brain injection of Ad-Cre and AAV-VEGF. The RFP+ and GFP+ and CD68+ cells in the bAVM were quantified. Results: The mice in both models had bAVM 8 weeks after model induction. The bAVM lesions had more CD68+ cells than the normal angiogenic region of wild-type (WT) mouse brain (Model 1 vs. WT: 562±182/mm2 vs. 353±86, P=0.049; and Model 2 vs. WT: 890±289 vs. 549±72, P=0.058). Most (95%) CD68+ cells in Model 2 were GFP+ microglia. Model 2 mice also had more RFP+ bone marrow (BM)-derived macrophages than WT controls (P=0.065), suggesting that unmutated BM-derived macrophages also participate in bAVM pathogenesis. A similar number of CD68+ cells was detected in the brain angiogenic foci in Model 1 mice (P=0.29) 2 weeks after model induction. Conclusions: These data indicate a consistent infiltration of active microglia in bAVM that causes unresolved inflammation, which then promotes abnormal angiogenesis and lesion progression. Unmutated BM-derived microphages also participate in this process.
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Briber, R. M., J. S. Fodor, T. P. Russell, R. D. Miller, K. R. Carter, and J. L. Hedrick. "Characterization of thin Polymeric Nanofoam films by Transmission Electron Microscopy and Small Angle Neutron Scattering." MRS Proceedings 461 (1996). http://dx.doi.org/10.1557/proc-461-103.

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ABSTRACTThin film polymer nanofoams are produced from triblock copolymers of a fluorinated polyimide, 3F/PMDA (derived from pyromelletic dianhydride (PMDA) and 1,1-bis(4-aminophenyl)-1-phenyl-2,2,2-trifluoroethane (3F)) as the center block and polypropylene oxide (PO) as the end blocks. The nanofoam is produced using a three step process: 1.) spin casting the triblock copolymer onto a silicon substrate, 2.) thermal treatment in an Argon atmosphere to imidize the center block and 3.) thermal treatment in air to degrade the PO domains and form nanoscale voids. This process was characterized using both transmission electron microscopy (TEM) and small angle neutron scattering (SANS). For the TEM studies, Ruthenium tetroxide staining was used to enhance the contrast between the polyimide (PI) matrix and the PO microdomains or voids, which permitted a more detailed view of the microstructure of both the foamed and unfoamed materials. From the two dimensional Fourier transform of the micrographs the spatial correlation between the PO microdomains in the unfoamed material and between the voids in the foam were found. An interdomain separation distance of -37 nm was observed. SANS was performed to follow the imidization and foaming processes both in-situ and on a Si substrate. The SANS results indicated that the films are homogeneous when spun from solution and that the microphase separation of the PO domains occurs during the imidization step. The subsequent foaming step leaves the morphology generally intact with the PO domains converting to voids. A peak was found in the SANS curve with a spacing of about 26 nm, which is qualitative agreement with the TEM data.
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Parietti, M., M. J. Merlo, M. Natal, and M. A. Méndez Casariego. "Reproductive compensation in female Palaemonetes argentinus (Decapoda: Natantia) due to Microphallus szidati (Trematoda) infection." Journal of Helminthology 94 (2020). http://dx.doi.org/10.1017/s0022149x20000917.

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Abstract Parasites may affect host demographic characteristics because they can directly or indirectly cause the death of their hosts and/or influence their reproduction. Parasitism is therefore recognized as a factor that influences the composition and structure of populations and communities. One of these behaviours is the compensatory response: the host can compensate for the parasite losses effect, modifying the reproductive effort to enhance fitness. Ovigerus female Palaemonetes argentinus was collected and sorted into two groups according to the degree of development of their embryos: newly spawned embryos and embryos ready to hatch. The number of embryos and their dry weight for each female were determined. All parts of the female body were checked for parasites. The females of P. argentinus were parasitized by Microphalus szidati. We found that parasitized females produce more embryos but had more egg loss during development and the percentage of embryonic loss was higher in the parasitized females than in non-parasitized. Parasitized females produced lighter eggs than those from uninfected females. This supports the compensatory reproduction hypothesis suggested for this species. Parasitism can change life history traits in a way that fecundity can be compensated; this co-evolution between host and parasites will be population or context dependent. Parasites are a functional part of any ecosystem and as our results show, deleting parasites in life history traits and reproduction studies in free living organisms could lead to an incomplete picture of the true processes that happen in nature.
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