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61.
Use of in‐situ atomic force microscopy to monitor the biodegradation of polyhydroxyalkanoates (PHAs)
Connie J. Rossini Justinn F. Arceo Evan R. McCarney Brian H. Augustine Douglas E. Dennis Michael D. Flythe Stephen F. Baron 《Macromolecular Symposia》2001,167(1):139-151
Thin films of a co‐polymer mixture of poly 3‐hydroxybutyrate and poly 3‐hydroxyvalerate P(3HB‐3HV) were spun‐cast onto glass slides resulting in 35 nm thick layers with a spherulitic microstructure. An untyped strain of Streptomyces sp. bacteria was isolated from soil samples, and it's PHA depolymerase was used to degrade the P(3HB‐3HV) thin films. Both ex‐situ and in‐situ atomic force microscopy (AFM) biodegradation studies were performed to determine the kinetics of the biodegradation over the course of three hours at room temperature. Ex‐situ AFM was performed in Tapping Mode and in‐situ AFM was performed in the PHA depolymerase using contact mode AFM in the liquid cell, allowing for the real‐time analysis of P(3HB‐3HV) biodegradation. Biodegradation is observed uniformly throughout the surface, and can be observed within 30 min. of depolymerase exposure. In‐situ AFM analysis yields a linear degradation rate as a function of time, while the ex‐situ study suggests a more complex kinetics. 相似文献
62.
High pressure assisted infusion of nutrients into food was in situ monitored with magnetic resonance imaging (MRI). Modification of an off-the-shelf pressure reactor with an MRI detection circuit provided a large enough volume to accommodate food. The model food used here was peeled apple flesh as it is considered as a good mimic for fibrous food. The nuclear spin relaxation properties of the water surrounding the apple flesh were enhanced by adding paramagnetic manganese cations. In this way, MRI relaxation contrast can be used to monitor the location of doped bulk water in and around the apple flesh during pressurization. This work tracked the efficiency of pressure induced nutrient infusion in situ, demonstrating that pressure gating and ramping offer no nutrient mass transport advantage over operation at constant pressure and that the presence of a peel expectedly disrupts solute transport into the fruit. High pressure assisted infusion, with all pressurization strategies shown here, yielded nearly 100-fold faster infusion times than at ambient pressure. 相似文献
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Sreeraj Gopi Augustine Amalraj Shintu Jude K.T. Benson Preetha Balakrishnan Józef T. Haponiuk 《高分子科学杂志,A辑:纯化学与应用化学》2019,56(4):327-340
Turmeric spent, a by-product of turmeric processing industries, was used as a source to prepare nanofibers (NF). The chemical treatments methods followed by acid hydrolysis accompanied with high pressure homogenization were used to prepare NF. The resulting turmeric nanofibers (TNF) were characterized by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA/DTA). The TNF presented needle like structure, high thermal stability, an average width of 38.5?nm, average length of 245.7?nm, and giving an aspect ratio (L/D) of 23.15. The prepared TNF showed pronounced antimicrobial activity against Bacillus cereus, Escherichia Coli, Salmonella typhimurium and Staphylococcus aureus and also registered good antioxidant activity. The results showed that TNF were successfully obtained from turmeric spent and might be potentially applied in different fields, such as pharmaceutical, biological active species, nutraceuticals, components for food industries and bionanocomposites. 相似文献
65.
Lellouche JP Perlman N Joseph A Govindaraji S Buzhansky L Yakir A Bruce I 《Chemical communications (Cambridge, England)》2004,(5):560-561
Magnetically responsive COOH-polydicarbazole-magnetite nanocomposites have been prepared by chemical oxidation of three COOH-dicarbazole monomers and - in the presence of magnetite nanoparticles. These functionalized nanoparticles have been tested for DNA hybridization experiments. 相似文献
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Dr. Guixiang Li Dr. Yalei Hu Prof. Dr. Meng Li Ying Tang Zuhong Zhang Dr. Artem Musiienko Qing Cao Fatima Akhundova Jinzhao Li Karunanantharajah Prashanthan Dr. Fengjiu Yang Patryk Janasik Augustine N. S. Appiah Sergei Trofimov Nikolaos Livakas Shengnan Zuo Luyan Wu Luyao Wang Dr. Yuqian Yang Dr. Benjamin Agyei-Tuffour Dr. Rowan W. MacQueen Dr. Boris Naydenov Dr. Thomas Unold Prof. Dr. Eva Unger Dr. Ece Aktas Prof. Dr. Siegfried Eigler Prof. Dr. Antonio Abate 《Angewandte Chemie (International ed. in English)》2023,62(39):e202307395
Stability issues could prevent lead halide perovskite solar cells (PSCs) from commercialization despite it having a comparable power conversion efficiency (PCE) to silicon solar cells. Overcoming drawbacks affecting their long-term stability is gaining incremental importance. Excess lead iodide (PbI2) causes perovskite degradation, although it aids in crystal growth and defect passivation. Herein, we synthesized functionalized oxo-graphene nanosheets (Dec-oxoG NSs) to effectively manage the excess PbI2. Dec-oxoG NSs provide anchoring sites to bind the excess PbI2 and passivate perovskite grain boundaries, thereby reducing charge recombination loss and significantly boosting the extraction of free electrons. The inclusion of Dec-oxoG NSs leads to a PCE of 23.7 % in inverted (p-i-n) PSCs. The devices retain 93.8 % of their initial efficiency after 1,000 hours of tracking at maximum power points under continuous one-sun illumination and exhibit high stability under thermal and ambient conditions. 相似文献
68.
Hydrolysis of gem-dibromomethylarenes bearing carboxylate or boronate group to corresponding aldehydes without affecting the ester group was successfully accomplished in high yields by subjecting them to refluxing pyridine. Both aromatic and heteroaromatic substrates gave the corresponding aldehydes in good yields. This method was efficiently adapted for the large scale synthesis of 2d and 2f. 相似文献
69.
Lellouche JP Govindaraji S Joseph A Jang J Lee KJ 《Chemical communications (Cambridge, England)》2005,(34):4357-4359
Novel functional polydipyrrole- and polydicarbazole nanorods have been AAO template-synthesized from COOH-dipyrrole/-dicarbazole monomers using Vapor Deposition and Liquid Phase Polymerizations (VDP and LPP). They were tested as insoluble supports for covalent DNA attachment and hybridization. 相似文献
70.
Kara Selvi Biermann Jennifer Lin Kuei Nuan O’Keefe Augustine 《Journal of Algebraic Combinatorics》2022,55(2):461-491
Journal of Algebraic Combinatorics - Let $$\mathcal {D}$$ be a weighted oriented graph and let $$I(\mathcal {D})$$ be its edge ideal in a polynomial ring R. We give the formula of... 相似文献